IFIP Advances in Information and Communication Technology
347
Editor-in-Chief A. Joe Turner, Seneca, SC, USA
Editorial Board Foundations of Computer Science Mike Hinchey, Lero, Limerick, Ireland Software: Theory and Practice Bertrand Meyer, ETH Zurich, Switzerland Education Arthur Tatnall, Victoria University, Melbourne, Australia Information Technology Applications Ronald Waxman, EDA Standards Consulting, Beachwood, OH, USA Communication Systems Guy Leduc, Université de Liège, Belgium System Modeling and Optimization Jacques Henry, Université de Bordeaux, France Information Systems Jan Pries-Heje, Roskilde University, Denmark Relationship between Computers and Society Jackie Phahlamohlaka, CSIR, Pretoria, South Africa Computer Systems Technology Paolo Prinetto, Politecnico di Torino, Italy Security and Privacy Protection in Information Processing Systems Kai Rannenberg, Goethe University Frankfurt, Germany Artificial Intelligence Tharam Dillon, Curtin University, Bentley, Australia Human-Computer Interaction Annelise Mark Pejtersen, Center of Cognitive Systems Engineering, Denmark Entertainment Computing Ryohei Nakatsu, National University of Singapore
IFIP – The International Federation for Information Processing IFIP was founded in 1960 under the auspices of UNESCO, following the First World Computer Congress held in Paris the previous year. An umbrella organization for societies working in information processing, IFIP’s aim is two-fold: to support information processing within its member countries and to encourage technology transfer to developing nations. As its mission statement clearly states, IFIP’s mission is to be the leading, truly international, apolitical organization which encourages and assists in the development, exploitation and application of information technology for the benefit of all people. IFIP is a non-profitmaking organization, run almost solely by 2500 volunteers. It operates through a number of technical committees, which organize events and publications. IFIP’s events range from an international congress to local seminars, but the most important are: • The IFIP World Computer Congress, held every second year; • Open conferences; • Working conferences. The flagship event is the IFIP World Computer Congress, at which both invited and contributed papers are presented. Contributed papers are rigorously refereed and the rejection rate is high. As with the Congress, participation in the open conferences is open to all and papers may be invited or submitted. Again, submitted papers are stringently refereed. The working conferences are structured differently. They are usually run by a working group and attendance is small and by invitation only. Their purpose is to create an atmosphere conducive to innovation and development. Refereeing is less rigorous and papers are subjected to extensive group discussion. Publications arising from IFIP events vary. The papers presented at the IFIP World Computer Congress and at open conferences are published as conference proceedings, while the results of the working conferences are often published as collections of selected and edited papers. Any national society whose primary activity is in information may apply to become a full member of IFIP, although full membership is restricted to one society per country. Full members are entitled to vote at the annual General Assembly, National societies preferring a less committed involvement may apply for associate or corresponding membership. Associate members enjoy the same benefits as full members, but without voting rights. Corresponding members are not represented in IFIP bodies. Affiliated membership is open to non-national societies, and individual and honorary membership schemes are also offered.
Daoliang Li Yande Liu Yingyi Chen (Eds.)
Computer and Computing Technologies in Agriculture IV 4th IFIP TC 12 Conference, CCTA 2010 Nanchang, China, October 22-25, 2010 Selected Papers, Part IV
13
Volume Editors Daoliang Li Yingyi Chen China Agricultural University EU-China Center for Information & Communication Technologies (CICTA) 17 Tsinghua East Road, Beijing, 100083, P.R. China E-mail: {dliangl, chenyingyi}@cau.edu.cn Yande Liu East China Jiaotong University College of Mechanical and Electronic Engineering Shuanggang Road, Nanchang, 330013 Jiangxi, China E-mail:
[email protected]
ISSN 1868-4238 e-ISSN 1868-422X ISBN 978-3-642-18368-3 e-ISBN 978-3-642-18369-0 DOI 10.1007/978-3-642-18369-0 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2010942867 CR Subject Classification (1998): I.2.11, H.4, C.3, C.2, D.2, K.4.4
© IFIP International Federation for Information Processing 2011 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer. Violations are liable to prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Typesetting: Camera-ready by author, data conversion by Scientific Publishing Services, Chennai, India Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)
Preface
I want to express my sincere thanks to all authors who submitted research papers to the 4th IFIP International Conference on Computer and Computing Technologies in Agriculture and the 4th Symposium on Development of Rural Information (CCTA 2010) that were held in Nanchang, China, 22–25 October 2010. This conference was hosted by CICTA (EU-China Centre for Information & Communication Technologies, China Agricultural University); China Agricultural University; China Society of Agricultural Engineering, China; International Federation for Information Processing (TC12); Beijing Society for Information Technology in Agriculture, China. It was organized by East China Jiaotong University. CICTA focuses on research and development of advanced and practical technologies applied in agriculture and aims at promoting international communication and cooperation. Sustainable agriculture is currently the focus of the whole world, and the application of information technology in agriculture has become more and more important. ‘Informatized agriculture’ has been the goal of many countries recently in order to scientifically manage agriculture to achieve low costs and high income. The topics of CCTA 2010 covered a wide range of interesting theories and applications of information technology in agriculture, including simulation models and decision-support systems for agricultural production, agricultural product quality testing, traceability and e-commerce technology, the application of information and communication technology in agriculture, and universal information service technology and service systems development in rural areas. We selected 352 best papers among those submitted to CCTA 2010 for these proceedings. It is always exciting to have experts, professionals and scholars getting together with creative contributions and sharing inspiring ideas which will hopefully lead to great developments in these technologies. Finally, I would like also to express my sincere thanks to all the authors, speakers, session chairs and attendees for their active participation and support of this conference.
October 2010
Daoliang Li
Conference Organization
Organizer East China Jiaotong University
Organizing Committee Chair Yande Liu
Academic Committee Chair Daoliang Li
Conference Secretariat Lingling Gao
Sponsors China Agricultural University China Society of Agricultural Engineering, China International Federation for Information Processing, Austria Beijing Society for Information Technology in Agriculture, China National Natural Science Foundation of China
Table of Contents – Part IV
A Compression Method of Decision Table Based on Matrix Computation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Laipeng Luo and Ergen Liu
1
A Laplacian of Gaussian-Based Approach for Spot Detection in Two-Dimensional Gel Electrophoresis Images . . . . . . . . . . . . . . . . . . . . . . . . Feng He, Bangshu Xiong, Chengli Sun, and Xiaobin Xia
8
A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chun-Hua Xiao, Shao-Kun Li, Ke-Ru Wang, Yan-Li Lu, Jun-Hua Bai, Rui-Zhi Xie, Shi-Ju Gao, Qiong Wang, and Fang-Yong Wang
16
A New Color Information Entropy Retrieval Method for Pathological Cell Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Xiangang Jiang, Qing Liang, and Tao Shen
30
A New Palm-Print Image Feature Extraction Method Based on Wavelet Transform and Principal Component Analysis . . . . . . . . . . . . . . . . . . . . . . . Jia wei Li and Ming Sun
39
A Non-linear Model of Nondestructive Estimation of Anthocyanin Content in Grapevine Leaves with Visible/Red-Infrared Hyperspectral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . JiangLin Qin, Donald Rundquist, Anatoly Gitelson, Zongkun Tan, and Mark Steele
47
Application of Improved BP Neural Network in Controlling the Constant-Force Grinding Feed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Zhaoxia Chen, Bailin He, and Xianfeng Xu
63
A Semantic Middleware of Grain Storage Internet . . . . . . . . . . . . . . . . . . . . Siquan Hu, Haiou Wang, Chundong She, and Junfeng Wang
71
AE Feature Analysis on Welding Crack Defects of HG70 Steel Used by Truck Crane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yantao Dou, Xiaoli Xu, Wei Wang, and Siqin Pang
78
An Equilateral Triangle Waveguide Beam Splitter . . . . . . . . . . . . . . . . . . . . Zhimin Liu, Fengqi Zhou, Hongjian Li, Bin Tang, Zhengfang Liu, Qingping Wu, Aixi Chen, and Kelin Huang
89
Analysis and Implementation of Embedded SNMP Agent . . . . . . . . . . . . . Hubin Deng, Guiyuan Liu, and Lei Zhang
96
VIII
Table of Contents – Part IV
Application of Computer Technology in Advanced Material Science and Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yajuan Liu
103
Application of Interferometry in Ultrasonic System for Vibration . . . . . . . Zhengping Liu, Shenghang Xu, and Juanjuan Liu
108
Automatic Control System for Highway Tunnel Lighting . . . . . . . . . . . . . . Shijuan Fan, Chao Yang, and Zhiwei Wang
116
Comparative Study of Distance Discriminant Analysis and Bp Neural Network for Identification of Rapeseed Cultivars Using Visible/Near Infrared Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Qiang Zou, Hui Fang, Fei Liu, Wenwen Kong, and Yong He Current Situation and Prospect of Grassland Management Decision Support Systems in China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Qingwei Duan, Xiaoping Xin, Guixia Yang, Baorui Chen, Hongbin Zhang, Yuchun Yan, Xu Wang, Baohui Zhang, and Gang Li
124
134
Design Method and Implementation of Ternary Logic Optical Calculator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chunzhi Li and Junyong Yan
147
Design of Automatic Cutting and Welding Machine for Brake Beam-Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leping Liu, Mingdong Zhong, and Qizheng Dong
167
Design of Multifunction Vehicle Bus Controller . . . . . . . . . . . . . . . . . . . . . . Zhongqi Li, Fengping Yang, and Qirong Xing
177
Detection of Soil Total Nitrogen by Vis-SWNIR Spectroscopy . . . . . . . . . Yaoze Feng, Xiaoyu Li, Wei Wang, and Changju Liu
184
Development and Application of Tennis Match Video Retrieval Technology in Multimedia Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shehua Cao
192
Fault Diagnosis of Roller Bearing Based on PCA and Multi-class Support Vector Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Guifeng Jia, Shengfa Yuan, and Chengwen Tang
198
Health Status Identification of Connecting Rod Bearing Based on Support Vector Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yongbin Liu, Qingbo He, Ping Zhang, Zhongkui Zhu, and Fanrang Kong Investigation of the Methods for Tool Wear On-Line Monitoring during the Cutting Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hongjiang Chen
206
215
Table of Contents – Part IV
IX
Magnetic-Field-Based 3D ETREE Modelling for Multi-Frequency Eddy Current Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yu Zhang and Yong Li
221
Measurement of Self-emitting Magnetic Signals from a Precut Notch of Q235 Steel during Tensile Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lihong Dong, Binshi Xu, and Shiyun Dong
231
Modeling and Performance Analysis of Giant Magnetostrictive Microgripper with Flexure Hinge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Qinghua Cao, Quanguo Lu, Junmei Xi, Jianwu Yan, and Changbao Chu Non-destructive Measurement of Sugar Content in Chestnuts Using Near-Infrared Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jie Liu, Xiaoyu Li, Peiwu Li, Wei Wang, Jun Zhang, Wei Zhou, and Zhu Zhou
237
246
Nondestructive Testing Technology and Optimization of On-Service Urea Reactor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Xiaoling Luo and Lei Deng
255
Parameters Turning of the Active-Disturbance Rejection Controller Based on RBF Neural Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Baifen Liu and Ying Gao
260
Research of Intelligent Gas Detecting System for Coal Mine . . . . . . . . . . . Hui Chen
268
Research of Subway’s Train Control System Based on TCN . . . . . . . . . . . Qingfeng Ding, Fengping Yang, and Qixin Zhu
279
Shape Detection for Impeller Blades by Non-contact Coordinate Measuring Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shimin Luo
286
Simulation of Road Surface Roughness Based on the Piecewise Fractal Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Zhixiong Lu, Lanying Zhao, Xiaoqin Li, and Jun Yuan
294
Stress Analysis near the Welding Interface Edges of a QFP Structure under Thermal Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Zhigang Huang, Xuecheng Ping, and Pingan Liu
306
Study of Intelligent Diagnosis System for Mechanism Wear Fault Based on Fuzzy-Neural Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sanmao Xie
314
X
Table of Contents – Part IV
Study on Autonomous Path Planning by Mobile Robot for Road Nondestructive Testing Based on GPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lunhui Xu, Fan Ye, and Yanguo Huang
321
Study on Imitating Grinding of Two-Dimensional Ultrasonic Vibration Turning System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leping Liu, Wen Zhao, and Yuan Ma
333
Study on Optimal Path Changing Tools in CNC Turret Typing Machine Based on Genetic Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Min Liu, XiaoLing Ding, YinFa Yan, and Xin Ci
345
Study on the Problem and Countermeasure of Fruit Production Quality and Safety in Yanshan Mountain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Haisheng Gao, Bin Du, and Fengmei Zhu
355
Calculation and Analysis of Double-Axis Elliptical-Parabolic Compond Flexure Hinge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ping’ an Liu, Jianqun Cheng, and Zhigang Lai
361
Surface Distresses Detection of Pavement Based on Digital Image Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Aiguo Ouyang, Chagen Luo, and Chao Zhou
368
The Application Research of Neural Network in Embedded Intelligent Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Xiaodong Liu, Dongzhou Ning, Hubin Deng, and Jinhua Wang
376
The Theoretical Analysis of Test Result’s Errors for the Roller Type Automobile Brake Tester . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jun Li, Xiaojing Zha, and Dongsheng Wu
382
A Type of Arithmetic Labels about Circulating Ring . . . . . . . . . . . . . . . . . Ergen Liu, Dan Wu, and Kewen Cai
390
Application of CPLD in Pulse Power for EDM . . . . . . . . . . . . . . . . . . . . . . . Yang Yang and Yanqing Zhao
398
Application of IDL and ENVI Redevelopment in Hyperspectral Image Preprocessing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Long Xue
403
Design of Integrated Error Compensating System for the Portable Flexible CMMs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Qing-Song Cao, Jie Zhu, Zhi-Fan Gao, and Guo-Liang Xiong
410
Detecting and Analyzing System for the Vibration Comfort of Car Seats Based on LabVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ying Qiu
420
Table of Contents – Part IV
XI
Determination of Pesticide Residues on the Surface of Fruits Using Micro-Raman Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yande Liu and Tao Liu
427
Development of the Meter for Measuring Pork Quality Based on the Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Zhen Xing, Wengang Zheng, Changjun Shen, and Xin Zhang
435
Experimental Investigation of Influence on Non-destructive Testing by Form of Eddy Current Sensor Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fengyun Xie and Jihui Zhou
443
Feasibility of Coordinate Measuring System Based on Wire Driven Robot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ji-Hui Zhou, Qing-Song Cao, Fa-Xiong Sun, and Lan Bi
450
HSFDONES: A Self-Leaning Ontology-Based Fault Diagnosis Expert System Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XiangBin Xu
460
Nondestructive Measurement of Sugar Content in Navel Orange Based on Vis-NIR Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chunsheng Luo, Long Xue, Muhua Liu, Jing Li, and Xiao Wang
467
Numerical Simulation of Temperature Field in Selective Laser Sintering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jian Zhang, Deying Li, Jianyun Li, and Longzhi Zhao
474
Numerical Simulations of Compression Properties of SiC/Al Co-continuous Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mingjuan Zhao, Na Li, Longzhi Zhao, and Xiaolan Zhang
480
Simulation and Optimization in Production Logistics Based on eM-Plant Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XinJian Zhou, XiangBin Xu, and Wei Zhu
486
Simulation of Transient Temperature Field in the Selective Laser Sintering Process of W/Ni Powder Mixture . . . . . . . . . . . . . . . . . . . . . . . . . . Jiwen Ren, Jianshu Liu, and Jinju Yin
494
Study on Plant Nutrition Indicator Using Leaf Spectral Transmittance for Nitrogen Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Juanxiu Hu, Dongxian He, and Po Yang
504
Study on the Influence of Non-electrical Parameters on Processing Quality of WEDM-HS and Improvement Measures . . . . . . . . . . . . . . . . . . . Guangyao Xiong, Meizhu Zheng, Deying Li, Longzhi Zhao, Yanlin Wang, and Minghui Li
514
XII
Table of Contents – Part IV
Test Analysis and Theoretical Calculation on Braking Distance of Automobile with ABS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dongsheng Wu, Jun Li, Xiaoping Shu, Xiaojing Zha, and Beili Xu The Detection of Early-Maturing Pear’s Effective Acidity Based on Hyperspectral Imaging Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pengbo Miao, Long Xue, Muhua Liu, Jing Li, Xiao Wang, and Chunsheng Luo The Effects of Internal and External Factors on the Mechanical Behavior of the Foam Copper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Longzhi Zhao, Xiaolan Zhang, Na Li, Mingjuan Zhao, and Jian Zhang
521
528
537
Optimum Design of Runner System for Router Cover Based on Mold Flow Analysis Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tangqing Kuang and Wenjuan Gu
543
Design of Tread Flange Injection Mold Based on Pro/E . . . . . . . . . . . . . . . Huilan Zhou
555
Study on the Online Control System to Prevent Drunk Driving Based on Photoelectric Detection Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lu Liming, Yang Yuchuan, and Lu Jinfu
563
The Design and Simulation of Electro-Hydraulic Velocity Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fengtao Lin
568
Application of Background Information Database in Trend Change of Agricultural Land Area of Guangxi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Xin Yang, Shiquan Zhong, Yuhong Li, Weiping Lu, and Chaohui Wu
575
Reasons of the Incremental Information in the Updating Spatial Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Huaji Zhu, Huarui Wu, and Xiang Sun
583
Research on Non-point Source Pollution Based on Spatial Information Technology: A Case Study in Qingdao . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tao Shen, Jinheng Zhang, and Junqiang Wang
592
The Regulation Analysis of Low-Carbon Orientation for China Land Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bikai Gong and Bing Chen
602
A CDMA-Based Soil-Quality Monitoring System for Mineland Reclamation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dongxian He, Daoliang Li, Jie Bao, and Shaokun Lu
610
Table of Contents – Part IV
Design and Implementation of a Low-Power ZigBee Wireless Temperature Humidity Sensor Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shuipeng Gong, Changli Zhang, Lili Ma, Junlong Fang, and Shuwen Wang Land Evaluation Supported by MDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fengchang Xue Design and Development of Water Quality Monitoring System Based on Wireless Sensor Network in Aquaculture . . . . . . . . . . . . . . . . . . . . . . . . . Mingfei Zhang, Daoliang Li, Lianzhi Wang, Daokun Ma, and Qisheng Ding
XIII
616
623
629
Design of an Intelligent PH Sensor for Aquaculture Industry . . . . . . . . . . . Haijiang Tai, Qisheng Ding, Daoliang Li, and Yaoguang Wei
642
A Simple Temperature Compensation Method for Turbidity Sensor . . . . . Haijiang Tai, Daoliang Li, Yaoguang Wei, Daokun Ma, and Qisheng Ding
650
A Wireless Intelligent Valve Controller for Agriculture Integrated Irrigation System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nannan Wen, Daoliang Li, Daokun Ma, and Qisheng Ding
659
Evaluation of the Rural Informatization Level in Central China Based on Catastrophe Progression Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lingxian Zhang, Xue Liu, Zetian Fu, and Daoliang Li
672
GIS-Based Evaluation on the Eco-Demonstration Construction in China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lingxian Zhang, Juncheng Ma, Daoliang Li, and Zetian Fu
680
Modeling and Analysis of Pollution-Free Agricultural Regulatory Based on Petri-Net . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fang Wang, Qingling Duan, Lingzi Zhang, and Guo Li
691
An Online Image Segmentation Method for Foreign Fiber Detection in Lint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Daohong Kan, Daoliang Li, Wenzhu Yang, and Xin Zhang
701
An Efficient Iterative Thresholding Algorithms for Color Images of Cotton Foreign Fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Xin Zhang, Daoliang Li, Wenzhu Yang, Jinxing Wang, and Shuangxi Liu Application of Grey Prediction Model in Rural Informatization Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jing Du, Daoliang Li, Hongwen Li, and Lifeng Shen
710
720
XIV
Table of Contents – Part IV
Study on Evaluation Method for Chinese Agricultural Informatization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Xiaoqing Yuan, Liyong Liu, and Daoliang Li
727
Research on Calculation Method for Agricultural Informatization Contribution Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Liyong Liu, Qilong Pan, and Daoliang Li
735
An Empirical Research on the Evaluation Index Regarding the Service Quality of Agricultural Information Websites in China . . . . . . . . . . . . . . . . Liyong Liu, Xiaoqing Yuan, and Daoliang Li
742
Hyperspectral Sensing Techniques Applied to Bio-masses Characterization: The Olive Husk Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Giuseppe Bonifazi and Silvia Serranti
751
Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
765
A Compression Method of Decision Table Based on Matrix Computation Laipeng Luo and Ergen Liu School of Basic Sciences, East China Jiaotong University, Nanchang, P.R. China
[email protected]
Abstract. A new algorithm of attribute reduction based on boolean matrix computation is proposed in this paper. The method compresses the valid information stored in table into a binary tree, at the same time deleting the invalid information and sharing a branch about the same prefix information. Some relative concepts such as local core attributes, local attribute reduction and global core attributes, global attribute reduction are introduced. The conclusions that the global core set is the union of all local core sets and the global attribute reduction sets are the union of respective local attribute reduction sets are proved. The attribute reduction steps of the algorithm are presented. At last, The correctness and effectiveness of the new algorithm are also shown in experiment and in an example. Keywords: Rough Set, equivalence matrix, attribute reduction, information compression.
1 Introduction Rough set theory, introduced by Zdzislaw Pawlak in the early 1980s[1,2], is a new mathematical tool to deal with vagueness and uncertainty. This approach seems to be of fundamental importance to artificial intelligence and cognitive sciences, especially in the areas of machine learning, knowledge acquisition, deci-sion analysis, knowledge discovery from databases, expert systems, decision support systems, inductive reasoning, and pattern recognition[3,4,5]. Attribute reduction is one of the main applications of Rough set. The general problem of finding all reductions are NP-hard, thus it is important for attribute reduction of Rough set to design algorithms with lower price and investigate new computation method. A matrix computation method of Rough set was proposed by the author in[6,7]for information system. A matrix was seen as an internal representation of equivalence relations. By defining the operation of the equivalence matrix, matrices are applied to define dependencies between two subsets of attributes, significance of an attribute ect. The approach presents a series of algorithms and their time complexity of attribute reduction. However, there are still several problems to be solved for the method: (1)The number of objects has great influence on time complexity of these algorithms; (2)These algorithms need too many computations of matrices; (3)The method only discusses matrix computation for information system; (4) How to apply the method to variable precision Rough set model. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 1–7, 2011. © IFIP International Federation for Information Processing 2011
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L. Luo and E. Liu
With the above-mentioned motivation, in another paper[8],aiming at the problem that how to apply the matrix computation to variable precision Rough set model,we have proposed a measure and computation approach based on matrix about studying Rough set theory. In this paper, we will provide a new insight into attributes reduction in decision table. A compression method of decision table based on matrix computation is proposed.We shall prove the feasibility of the compression method in theory and show its effectiveness in experiment and in an agriculture example.
2 Equivalence Matrix of Decision Table Definition 2.1. Let U be a non-empty finite set of objects and R be equivalence relation on U, We denote the partition gived by the R as follows: U/R= {X1, X 2 ,...X n} . Definition 2.2. Let R be equivalence relation on U, then R is expressed in terms of a binary n×n requivalence matrix MR=[mij]n×n where n= U , mij
⎧1 xi Rx j =⎨ . or ⎩0
Definition 2.3. Let P=(pij)n×n,Q=(qij)n×n be two binary n×n matrices. The intersection P∩Q of matrices P and Q is defined as follows:P∩Q=[tij]n×n,where tij=min{pij,qij}. m
Definition 2.4. Let R={r1,r2,…,rm},then M R = I M ri . i =1
Definition 2.5. LetC,D be equivalence relation and MC =(cij)n×n, MD =(dij)n×n be their matrices respectively. If for arbitrary positive integer i,j, cij≤dij,then M C ≤ M D .
∪
Definition 2.6. Let S=(U,R=C D,V,f) be a decision table, where C is condition attributes and D is decision attributes, Then S is consistent if and only if M C ≤ M D . Definition 2.7. Let S=(U,R=C
∈
∪ D,V,f, M ≤ M ) be a decision table, Given an C
D
attribute a C, then attribute a is nonsignificant in C if M{C−a} ≤ MD .
∪
Definition 2.8. Let S=(U,R=C D,V,f, MC ≤ MD ) be a decision table. The set of all attributes
C ′′ ⊆ C which are significant in S is called the core set of C.
Definition 2.9. Let S=(U,R=C
∪D,V,f, M ≤ M ) be a decision table. A subset T ′ of C C
D
is said to be a attribute reduction of C if and only if
T ′′ ⊂ T ′, then : MT′ > MD .
T ′ satisfies: (1) MT′ ≤ MD ; (2)if
3 Theory Analysis of Matrix Computation Put [R]ij express the element in row i and in column j of MR, where R={r1,r2,…,rm}. Obviously, [R]ij has the following properties:
A Compression Method of Decision Table Based on Matrix Computation
∧ ∧ ∧
3
(1) [R]ij =[r1]ij [r2]ij … [rm]ij(i=1,2…n,j=1,2…n);(2)if [R]ij =1,then for arbitrary rk R, [rk]ij =1;(3) if [R]ij =0,then there at least exist an attribute rk R,such that [rk]ij =0.Referring to properties,we immediately derive the following facts:
∈
Theorem 3.1. Let S=(U,R=C
∈
∪D,V,f, M ≤ M ) be a decision table. A subset T ′ of C C
D
is said to be a attribute reduction if and only if for any [D]ij=0 in MD, [ T ′ ]ij satisfies:(1) [ T ′ ]ij=0;(2)There no exist T ′′ ⊆ T ′, such that [ T ′′ ]ij=0.
∪ D,V,f,
MC ≤ MD ) be a decision table where C={c1,c2,…,cm}.c C is core attribute if and only if there at least exist positive integer i,j,( i=1,2…n,j=1,2…n) such that [D]ij=0, [c]ij=0,but for any b C-c, [b]ij=1. Theorem 3.2. Let S=(U,R=C
∈
∈
∈
∈
Proof. Let c C be core attribute.If there exist some attribute b C(c≠b),such that [b]ij=0,for any[D]ij=0 ,[C]ij=min {[c1]ij,[c2]ij,…[cm]ij}=0, then after deleting attribute b in C,we have M{C−c} ≤ MD .Thus there exist attribute set C ′ ⊆ {C-c},such that C ′ is attribute reduction of S which contradict that c is core attribute in S. Conversely, if there exist positive integer i,j,(i=1,2…n,j=1,2…n), such that [D]ij=0, [c]ij=0,and [b]ij=1 for every b C-c,then after deleting attribute b in C,we have [C]ij=0≠[C-c]ij=1.Thus c is core attribute in S by theorem 3.1.
∈
Definition 3.1. Let S=(U,R=C
∪D,V,f, M ≤ M ) be a decision table. If there exist C
D
positive integer i,j, such that attribute c satisfies [c]ij=0, [C-c]ij=1 when [D]ij=0, [C]ij=0,then attribute c is called local core attribute of decision table S.
∪
Theorem 3.3. If c1,c2…,ck be all local core attribute of S=(U,R=C D,V,f, M C ≤ M D ), then core attribute set C ′ of decision table S is
k
Uc
i =1
i
.That is, C ′ =
k
Uc . i =1
i
Definition 3.2. Core attribute set C ′ of decision table S is called global core attributes.
∪D,V,f, M ≤ M ) be a decision table and C′ be core
Definition 3.3. Let S=(U,R=C
∈
C
D
attribute set.If ak C- C ′ satisfies that there exist positive integer i,j,such that [ C ′ ]ij=1, [C]ij=0 and [ak]ij=0,then attribute set C ′ {ak} is called a local attribute reduction of decision table S. Obviously, local attribute reduction derived by [C]ij=0 can has not only one. All local attribute reduction derived by [C]ij=0 is called a local attribute reduction set.
∪
Definition 3.4. Attribute reduction set T ⊂C of decision table is called global attribute reduction. Theorem 3.4. Let B1,B2…,Bk be all local attribute reduction sets of decision table S=(U,R=C D,V,f, MC ≤MD ),where Bi ={Ai1, Ai2,L, Aiki }(1≤ i ≤ k) and Aij (1 ≤ j ≤ ik ) is
∪
a local reduction.If Tt is attribute reduction,then Tt satisfies:(1) If for arbitrary positive
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L. Luo and E. Liu k
integer i,j, Bi∩Bj=φ,then Bi∩Bjφ,then
Tt = UAip ,1 ≤ p ≤ ik ; (2) If there exist positive integer i,j, i=1
Tt = UAip ,1 ≤ p ≤ ik where for any Aim,Ajn
∈T , A t
im,Ajn
must satisfy
Aim ∉ B j ٛor Ajn ∉ Bi . k
Proof. (1) Put
Tt = UAip and let C ′ be core attribute set.There at least exist an i =1
b ∈ Tt for any [D]ij=0,[C]ij=0,such that [b]ij=0.That is [ Tt ]ij=0. On the other hand,for arbitrary B⊂Tt , Suppose B ∪ ck = Tt and C′ ∪ ck ∈ Bm By definition3.2 there exist positive integer p,q,such that [C′]pq =1,[ck ]pq =0 While for arbitrary i,j, if attribute
.
。
Bi∩Bj=φ, then [B]pq =[Tt −ck ] ≠0 By theorem 3.1,attribute set B is not attribute reduction of system S. k
(2) If there exist positive integer i,j,Bi∩Bj≠φ, then
Tt = UAip ,1 ≤ p ≤ ik is not the i=1
optimal attribute reduction of system S.It is fact that if Bi∩Bj = A′ and
′ A′ ≠ Ajm ∈ B j ,then A′ ∪Ajm ⊆Tt is not the optimal attribute reduction. Hence, by above (1), if for any
Aim ∈ Bi , A jn ∈ Bj and Aim, Ajn ∈Tt , Aim,Ajn satify
Aim ∉ Bj ٛor A jn ∉ B i then Tt = UAip,1≤ p ≤ ik is the optimal attribute reduction.
4 Compression of Decision Table Because equivalence matrices of attribute set are symmetric, in practical application, we pay attentin to the upper-triangle above the diagonal or the lower- triangle below the diagonal. Let C={c1, c2,…, cr} be condition attribute set and D be decision attribute set. For arbitrary positive integer i,j, we obtain: [C]ij =[c1]ij [c2]ij … [cr]ij.By theorem 3.1,in practical application, we only devote our attention to [D]ij = 0 and [C]ij = 0 in the upper-triangle above the diagonal or the lower- triangle below the diagonal. In this paper,we compress information of [D]ij = 0 and [C]ij = 0 in the equivalence matrix into a binary tree where [c1]ij,[c2]ij,… [cr]ij are orderly arranged and nodes of the tree. Please refer to below for details. First, create the root of the tree, labeled with “null”. Scan the elements of MD a time and find all positive integer i,j which satisfy [D]ij = 0.The corresponding elements of each equivalence relation matrix of condition attributes orderly sorted lead to the construction of the first branch of the tree with r nodes where [c1]ij is linked as a child of the root, [c2]ij is linked to [c1]ij. The rest may be deduced by analogy.
∧ ∧ ∧
∧
A Compression Method of Decision Table Based on Matrix Computation
5
∧
The second [c1]mn,[c2]mn,… [cr]mnwould result in a branch where [c1]mn is linked as a child of the root, [c2]mn is linked to [c1]mn.the rest may be deduced by analogy. Howeve, this branch would share an existing path with other branchs if along the root node, some branch has the common prefix. For example, if [c1]ij=[c1]mn, [c2]ij=[c2]mn, [c3]ij≠[c3]mn, then the first two nodes of the branch which contains [c1]ij, [c2]ij … [cr]ij is the same as the branch which contains[c1]mn, [c2]mn … [cr]mn.The rest branches may be constructed by analogy. By theorem 3.2, definition 3.2, all local core attributes and all local attribute reducion are derived from these branches. By theorem 3.3,3.4, we get global core attributes and global attribute reduction.
∧ ∧
∧ ∧
5 Description of Attribute Reduction Algorithm Let S=(U,R=C
∪D,V,f, M
C
≤ M D ) be a decision table.
Step1: Compute the equivalence matrices of decision attribute set and each of condition attributes ,and arrage the equivalence matrices of each of condition attributes in ordor; Step2: According to [D]ij = 0,compress [c1]ij,[c2]ij,… [cr]ij into a binary tree where [ck]ij,(k=1,2,…r)is node of the tree. Step3: Scan the tree and find the only zero value node in every branch.We get local core of every branch. Core set of system S is union of all local core. Step4: Prune the branch that includes local core and at the same time, retain shareable prefix part. Step5: Travel every branch of binary tree pruned and find local attribute reduction sets of all branchs
∧
Step6: Compute attribute reduction of system S according to {Tt Tt =
UA
ip
,1 ≤ p ≤ ik }
6 Algorithm Analysis The time complexity of algorithm in [7] for finding all core attributes is 2
2
C
2
o( C U ) ,and for finding all attribute reduction is o(2 C U ) . The time complexity of algorithm in this paper for finding all core attributes is at most C +1
C +1
o(2 ) ,and for finding all attribute reduction is at most o(2×2 ) . In general, U >> C ,hence,the method presented in this paper has an advantage over the method in [7]. Next, to compare the two methods, We made the relevant experiments on monks datasets in UCI database. The datasets have one decision attribute, six conditon attributes and 423 records. We did four experiments with the first 100,150,300,423 recordes of standard datasets monks datas. The experiment environment is Petium4 2.1GMHZ,RAM512M, windows XP. The results are as follows:
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L. Luo and E. Liu Table 1. Run time of two algorithms
5XQ WLPH
after com pression
beforer com pression
'DWD VHW
The chart shows that the method presented in this paper is efficient and scalable for finding core attributes set and attribute reduction sets, and is faser than the method in [7].
7 An Application Example in Agriculture The following is knowledge representation system of cotton diseases. The condition attributes are a-“diseased spot color”, b-“disease site”,c-“disease shape”,d-“feature” and the decision attribute is e-“the type of disease”. {1,2,3} represent the different value of each attribute. Table 2. Knowledge representation system
According to the method proposed in this paper,we can obtain that the core attribute is {a} and the attribute reduction set are {a,b} and {a,c,d}.The conclusion is the same as the other method.That is to say that diseased spot is chief factor to judge the type of disease and diseased spot color, disease site or diseased spot color, disease shape, feature may judge exactly the type of disease.
8 Conclusion In this paper, We further discuss the approach of matrix computation about Rough set and applied it to dicision table. In theory, we have proved the relation between the
A Compression Method of Decision Table Based on Matrix Computation
7
elements of equivalence matrice and core attributes,attribute reduction. At the same time, we suggest an attribute reduction algorithm based on a storage structure of binary tree which can compress the invalid and the same prefix information. The algorithm designed is lower price. We also find that by changing the order of condition attributes sorted, the algorithm is more efficient.
References [1] Pawlak, Z.: Rough Sets. International Jounal of Information and Computer Science 11(5), 341–356 (1982) [2] Pawlak, Z.: Rough Sets: Theoretical Aspects of Reasoning about data. Kluwer Academic Publishers, Dordrecht (1991) [3] Wang, G.Y., Hu, F., Huang, H., Wu, Y.: A granular computing model based on tolerance relation. The Journal of China Universities of Post s and Telecommunications 12(3), 86–90 (2005) [4] Greco, S., Wojna, A.G., Slowinski, R.: Fuzzy rough sets and multiple-premise gradualdecision rules. International Journal of Approximate Reasoning 41(2), 179–211 (2006) [5] Lin, T.Y., Yin, P.: Heuristically fast finding of the shortest reducts. In: Tsumoto, S., Słowiński, R., Komorowski, J., Grzymała-Busse, J.W. (eds.) RSCTC 2004. LNCS (LNAI), vol. 3066, pp. 465–470. Springer, Heidelberg (2004) [6] Guan, J.W., Bell, D.A.: Matrix computational method for information systems. Artificial Intelligence 105, 77–103 (1998) [7] Guan, J.W., Bell, D.A., Guan, Z.: Matrix computation for information systems. Information Sciences 131, 129–156 (2001) [8] Luo, L., Liu, E., Yi, C.: Matrix approach to the study of rough set theory. Systems Engineering and Electrionics 31(4), 859–862 (2009) (in chinese)
A Laplacian of Gaussian-Based Approach for Spot Detection in Two-Dimensional Gel Electrophoresis Images Feng He, Bangshu Xiong, Chengli Sun, and Xiaobin Xia Key Laboratory of Nondestructive Test of Ministry of Education, Nanchang Hangkong University, 330063 Nanchang, P.R. China
[email protected],
[email protected]
Abstract. Two-dimension gel electrophoresis (2-DE) is a proteomic technique that allows the analysis of protein profiles expressed in a given cell, tissue or biological system at a given time. The 2-DE images depict protein as spots of various intensities and sizes. Due to the presence of noise, the inhomogeneous background, and the overlap between the spots in 2-DE image, the protein spot detection is not a straightforward process. In this paper, we present an improved protein spot detection approach, which is based on Laplacian of Gaussian algorithm, and we extract the regional maxima by morphological grayscale reconstruction algorithm, which can reduce the impact of noisy and background in spot detection. Experiments on real 2-DE images show that the proposed approach is more reliable, precise and less sensitive to noise than the traditional Laplacian of Gaussian algorithm and it offers a good performance in our gel image analysis software. Keywords: Two-dimensional gel electrophoresis, Spot detection, Laplacian of Gaussian, Morphological grayscale reconstruction.
1 Introduction Proteomic research deals with the systematic analysis of protein profiles expressed in a given cell, tissue or biological system at a given time. In this field, two-dimensional gel electrophoresis (2-DE) is a well-established and widely used technique to separate proteins extracted from sample for identification and analysis of differential expression, according to their isoelectric points and molecular weight [1]. The result of that process is many dark spots on the gel, and each spot represents a protein or a group of proteins. The two-dimensional gel electrophoresis (2-DE) images show the expression levels of several hundreds of proteins where each protein is represented as a spot of grey level values [2]. In order to extract protein spots, image processing techniques can help us to analyze proteins further. Each spot can be characterized by its location and other information, such as area, volume, intensity, etc. Due to the presence of noise, the inhomogeneous background, and the overlap between the spots in 2-DE image, the protein spot detection is not a straightforward process. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 8–15, 2011. © IFIP International Federation for Information Processing 2011
A Laplacian of Gaussian-Based Approach for Spot Detection in 2-DE Images
9
A variety of software packages have been developed for protein spot detection [3]. Many of these packages implement image segmentation methods based on edge detection algorithms such as Laplacian filtering, in conjunction with smoothing operators. However, if a 2-DE image contains artifacts and noise, such as cracks in the gel surface, fingerprints, dust and other pollutions, they will lead to spurious spot detection [4]. The watershed transformation algorithm has also been a popular choice for 2-DE image segmentation [3] [5]. State of the art approaches to spot detection by image segmentation include geometric algorithms [6], parametric spot models [3] and the pixel value collection method [2] [7]. In this article, we introduce an improved protein spot detection approach that is based on Laplacian of Gaussian algorithm, in conjunction with morphological grayscale reconstruction to extract the regional maxima in 2-DE images. The proposed approach extracts the regional maxima of the Gaussian-smoothed gel image by morphological grayscale reconstruction algorithm [8], and uses the second derivative (laplacian) and direction of the gaussian-smoothed gel image as well as neighborhood connectivity properties in determining spot extents. Relative to the traditional Laplacian of Gaussian algorithm, our approach can reduce the impact of noise and avoid the spurious spot detection by using morphological grayscale reconstruction algorithm to restrict regional maxima, and the results are more reliable and precise. The rest of this paper is organized as follows: Section 2 describes the spot detection approach which has been applying in our soft, Section 3 presents the experimental results, and Section 4 presents conclusions and the future work.
(a)
(b)
Fig. 1. (a) Original Image, (b) Inverted Image
2 Algorithm In the following description it is assumed that the original image shows in Fig. 1a is inverted, that is, the image background is dark, and the spots appear as light peaks rising from the background in Fig. 1b. The proposed approach to protein spot detection consists of the following steps: a) Smooth the original gel image; b) Extract the regional maxima of the smoothed image by grayscale reconstruction algorithm;
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F. He et al.
c) Compute the Laplacian of the smoothed image and define central core regions where the Laplacian pixels are negative in both x and y directions; d) Extract all of spot regions; e) Estimate background density and normalize the valid spot quantifications. 2.1 Image Smoothing Operations During the detection process, the gel images are normally very noisy, so we must implement smoothing filter to reduce high frequency noise in 2-DE image at first. If the image is not sufficiently smoothed, it will find the edges of the spots incorrectly and generate spurious regional maxima. In the proposed approach, we use a Gaussian low-pass filter with a window (e.g. 3x3, 5x5, 7x7, etc) to smooth the inverted image. 2.2 Regional Maxima Extraction Grayscale reconstruction is a very useful operator provided by mathematical morphology. The regional maxima and minima are important features of images; they often represent the corresponding image goal: the regional maxima correspond to the light goal, and the region minima correspond to the dark goal. Grayscale reconstruction turns out to provide a very efficient method to extract regional maxima and minima from grayscale images. Furthermore, the technique extends to the determination of “maximal structures” called h-domes [8]. The h-dome transformation is illustrated on Fig. 2. The h-dome transformation extracts light structures without involving any size or shape criterion. The only parameter (h) is related to the height of these structures. This characteristic is of interest for complex segmentation problems. The h-dome image Dh(I) of the h-domes of a grayscale image I is given by Dh(I)=I-RIδ(I-H) . where
RIδ(I-H)
(1)
is the dilated reconstruction of I from I-h.
Fig. 2. Determination of the h-domes of grayscale image I
In the proposed approach, we can execute h-dome transformation to extract light maximal structures of the smoothed image. It can restrain all maxima, the depth of which are less than or equal to the parameter (h), and reduce the impact of noisy in spot detection.
A Laplacian of Gaussian-Based Approach for Spot Detection in 2-DE Images
11
2.3 Image Laplacian Operations 2-DE images show the expression levels of several hundreds of proteins where each protein is represented as a spot of grey level values. Under optimal density within the area of the spot appears as a monotonically increasing function as illustrated in Fig. 3a. The Laplacian or second derivative of this function is shown in Fig. 3b. We define the central core region of negative values for digital approximations to both partial second derivatives, with respect to x and y directions, as the central core region. The region on the outside of the central core is propagated until it reaches the extent of the positive peaks of the side lobes. This propagated central core region, computed in two dimensions, is then effectively used as a mask for quantitating that spot [5]. This is the reason we want to use the Laplacian for helping to analyze the image.
(a)
(b)
Fig. 3. (a) Cross section of the ideal spot, (b) Laplacian of this ideal spot cross section
After acquired the smoothed image, it is used when computing the digital approximation of the Laplacian of this image. We store the Laplacian direction and magnitude values in two additional images. All laplacian direction image pixels are set to 1, if the Laplacian values are negative in both x and y, otherwise they are set to 0. This directional image defines the initial central core regions of a gel. The central core regions are propagated to adjacent pixels until they reach the maximum value of the Laplacian magnitude image. These final regions are called the propagated central core region and, after some corrections, define the extent of the spot to be quantitated. The next step describes the extraction of each spot region in the proposed approach. 2.4 Spot Region Extraction After the image laplacian operations, the next step is to extract all of the spot regions in sequential raster search of the central core image. The central core regions are propagated to adjacent pixels until they reach the maximum value of the Laplacian magnitude image. These final regions are called the propagated central core region and, after some minor corrections, define the extent of the spot to be quantitated. The steps in finding the final propagated central core for the current spot are enumerated as follows. This algorithm is iterated for each spot as it traverses down the image in a raster pattern. Step1. Find the central core for the current spot in the Laplacian direction image, where the central core regions are set to 1 and the other set to 0. Given a new spot pixel to find all (x, y) pairs that are 4-neighbor connected to this spot with central core pixel, and save this pairs in a list.
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F. He et al.
Step2. If the central core size is less than the threshold which is the minimum of central core size, then delete the spot, and set that region to 0 in the central core image. Step3. There are situations where some spots are merged into single spots. If the central core size is greater than the threshold which is the minimum to split, then try to split the spot into several spots. Step4. Try to find saturated spots, if the (max Density of the spot)/ (max Density in the image) is greater than percent threshold of the darkest pixel, then try to fill holes in the saturated spot with central core pixels. Step5. Remove concavities which with 0 values between central core pixels with central core value in the current central core spot. Step6. Remove interior central core pixels to speed up the subsequent steps and obtain the edge of the central core. This is useful for segmenting very large spots when using very high pixel resolution. Step7. Propagate the central core to a propagated central core by looking for the maxima away from the center of the spot in all directions. This propagation is terminated by various conditions including running into another spot, noise, etc. If the image is not adequately smoothed, this step will not work very well. Step8. Optimize the propagated central core region. We can fill holes in the propagated central core such that central pixels with 0 values are filled with propagated central core value. Step9. Delete the spurious propagated central core. If the propagated central core region does not contain a regional maximum, so it is a spurious propagated central core, and we could delete it. Step10. Finally, compute the spot features using data from the original image and save the features for this spot in a list of all spots. The spot features include density weighted centroid, standard deviation and covariance spot size, density, area and volume. 2.5 Background Density Estimation and Spot Quantification After all spots are initially segmented, it then performs background correction and normalization on the quantifications. If the background appears relatively uniform, we have hound subtracting global minimum intensity for the gel works sufficiently well. However, the background appears to be spatially varying, we use a smoothing low pass filter to estimate the background [9]. First a rest of image is computed as the original image less the segmented spots with the spots having density value 0. Then the filter is computed over the entire image by moving an averaging window (e.g. 32x32) over the image in a raster, 1 pixel at a time where the mean density is computing in the averaging window at each point not including the 0 values. This background image is used to estimate the background for each spot and correct the spot density. To normalize, we divide each spot intensity on a given gel by the mean spot intensity for that gel, and save the spot features in a list, including location, area, volume, normalized intensity, etc. The researchers can use these spot features to do next analysis, such as spot matching.
A Laplacian of Gaussian-Based Approach for Spot Detection in 2-DE Images
13
3 Experimental Results In this section, the results for detection the protein spots in a gel image by those methods mentioned in Section 2 are presented. In our approach, we firstly inverted the original image, that is, the image background is dark, and the spots appear as light peaks rising from the background. We smoothed the inverted image by Gaussian low-pass filter, if the image is not sufficiently smoothed, it will find the edges of the spots incorrectly and generate spurious regional maxima. Fig. 4a shows the regional maxima labeled by red color. Fig. 4b and Fig. 4c show the Laplacian magnitude image and the directional image which defines the initial central core regions of a gel. The central core regions are propagated to adjacent pixels until they reach the maximum value of the Laplacian magnitude image. These final regions are called the propagated central core region and, after some minor corrections, we can get the optimized propagated central core region in Fig. 4d, is then effectively used as a mask for quantitating that spot, and the background image in Fig. 4e. Finally, we can get the final result as Fig. 4f, described the spot contour by red color.
(a)
(b)
(c)
(d)
(e)
(f)
Fig. 4. The process of the protein spots detection with the improved Laplacian of Gaussian approach: (a) regional maxima on original image, (b) central core regions, (c) laplacian magnitude image, (d) final propagated central core regions that are optimized, (e) background image, (f) final result.
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As shown in Fig. 4f, we detected 374 protein spots, almost protein spots can be detected and their contours are very clear based on the proposed approach. Fig. 5 shows the result of the Laplacian of Gaussian algorithm, which detected 506 protein spots without morphological grayscale reconstruction algorithm to restrict regional maxima, however, affected by the stripe noise and artifacts, some of them are the spurious spots. On the other hand, the proposed approach is less sensitive to noisy.
Fig. 5. The final result of traditional Laplacian of Gaussian algorithm
4 Conclusions We present an improved protein spot detection approach which can effective detects and quantifies the protein spots in 2-DE images. The spot detection approach applies morphological grayscale reconstruction algorithm to restrict regional maxima, and the Laplacian of Gaussian algorithm to detect spot regions. The 2-DE image often contains artifacts and noise, and they will lead to spurious spot detection. The morphological grayscale reconstruction algorithm can restrict those spurious regional maxima very well, and reduce the impact of noisy in spot detection. The experimental results show that the proposed approach is more reliable, precise and less sensitive to noise than the traditional Laplacian of Gaussian algorithm and it offers a good performance in our gel image analysis software. Future works include further experimentation, optimization and parallelization of the proposed approach, and its integration in a complete user-friendly software application. Also variation of the proposed approach will be used to detect all spots in heavily polluted 2-DE images. Acknowledgments. This work was supported by Postgraduate Innovation Fund of Jiangxi Province (YC09A112), Postgraduate Innovation Fund of Nanchang Hangkong University (YC2009008), Scientific Research Fund of Jiangxi Provincial Education Department (GJJ09183) and Jiangxi Nature Science Fund (No.2008GZS0032).
References 1. Safavi, H., Correa, N.: Independent Component Analysis of 2-D Electrophoresis Gels. Electrophoresis 29, 4017–4026 (2008) 2. Peer, P., Corzo, L.G.: Local Pixel Value Collection Algorithm for Spot Segmentation in Two-Dimensional Gel Electrophoresis Research. Comparative and Functional Genomics, 1–9 (2007)
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3. Berth, M., Moser, F.M.: The State of the Art in the Analysis of Two-Dimensional Gel Electrophoresis Images. Appl. Microbiol. Biotechnol. 76, 1223–1243 (2007) 4. Rye, M.B., Alsberg, B.k.: A Multivariate Spot Filtering Model for Two-Dimensional Gel Electrophoresis. Electrophoresis 29, 1369–1381 (2008) 5. Srinark, T., Kambhamettu, C.: An Image Analysis Suite for Spot Detection and Spot Matching in Two-Dimensional Electrophoresis Gels. Electrophoresis 29, 706–715 (2008) 6. Morris, J.S., Clark, B.N., Gutstein, H.B.: Pinnacle: a Fast, Automatic and Accurate Method for Detecting and Quantifying Protein Spots in 2-Dimensional Gel Electrophoresis Data. Bioinformatics 24, 529–536 (2008) 7. Rye, M.B., Færgestad, E.M., Martens, H.: An Improved Pixel-Based Approach for Analyzing Images in Two-Dimensional Gel Electrophoresis. Electrophoresis 29, 1382–1393 (2008) 8. Soille, P.: Morphological Image Analysis: Principles and Applications, 2nd edn. Springer, Heidelberg (2003) 9. Van Belle, W., Sjøholt, G., Anensen, N.: Adaptive Contrast Enhancement of TwoDimensional Electrophoretic Protein Gel Images Facilitates Visualization, Orientation and Alignment. Electrophoresis 27, 4086–4095 (2006)
A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains Chun-Hua Xiao1,2, Shao-Kun Li1,2,3,*, Ke-Ru Wang1,2, Yan-Li Lu2, Jun-Hua Bai2, Rui-Zhi Xie2, Shi-Ju Gao2, Qiong Wang2, and Fang-Yong Wang1 1
Key Laboratory of Oasis Ecology Agriculture of Xinjiang Construction Crop/ Center of Crop High-Yield Research, Shihezi 832003, Xinjiang, China 2 Institute of Crop Science, Chinese Academy of Agricultural Sciences / National Key Facility for Crop Gene Resources and Genetic Improvement, NFCRI, Beijing 100081, China 3 Department of Crop Culture, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China Tel.: +86-010-68918891
[email protected]
Abstract. The spectral signatures of crop canopies in the field provide much information relating morphological or quality characteristics of crops to their optical properties. This experiment was conducted using two winter-wheat (Triticum aestivum) cultivars, Jingdong8 (with erect leaves) and Zhongyou9507 (with horizontal leaves). We analysiced the relation between the direction spectral characteristics and the laeves nitrogen content(LNC). The result showed that the spectral information observed at the 0° angle mainly provided information on the upper canopy and the lower layer had little impact on their spectra. However, the spectral information observed at 30° and 60° angles reflected the whole canopy information and the status of the lower layer of the canopy had great effects on their spectra. Variance analysis indicated that the ear layer of canopy and the topmost leaf blade made greater contributions to CDS. The predicted grain protein content (GPC) model by leaf layers spectra using 0° view angle was the best with root mean squares (RMSE) of 0.7500 for Jingdong8 and 0.6461 for Zhongyou9507. The coefficients of determination, R2 between measured and estimated grain protein contents were 0.7467 and 0.7599. Thus, grain protein may be reliably predicted from the leaf layer spectral model. Keywords: wheat canopy, leaf distribution, direction spectra, view angle, model.
1 Introduction The spectral characteristics of a crop canopy are determined not only by biophysical and biochemical features and also plant structural attributes. Leaf optical properties are a main factor for canopy spectral. *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 16–29, 2011. © IFIP International Federation for Information Processing 2011
A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains
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Crop canopy spectral characteristics represent important information needed to guide crop management. Crop composition and structure are difficult to assess by traditional spectral measurement with vertical canopy direction. The direction spectrum includes a great deal of crop canopy information. Multiangle data significantly improved the accuracy of recovering forest parameters when inverting 3-D optical models (Kimes et al., 2002) but forest vertical structure can not be captured accurately using only the 4 spectral bands in the nadir view or all view angles with a single spectral band (Kimes et al.,2006). Directional radiances in or near the principal plane of the sun provides information that leads to more accurate prediction of canopy structure parameters than from other azimuth planes (Gobron et al., 2000). Canopy emissivity increased with increasing view angle due to the greater proportion of vegetation observed at off-nadir view angles; when the proportion of leaves was lower than that of soil, canopy emissivity grew with increasing view angle (Sobrino et al., 2005). It should be noted that these models assume a Lambertian behaviour for soil and vegetation surfaces. Although vegetation surfaces show a near Lambertian behaviour, bare soil surfaces do not and the angular variation on emissivity can not be neglected. Lidars, multiangle radiometers, radars and imaging spectrometers have been identified as systems that can capture information in the vertical dimension. This requires a capability to remotely measure the vertical and spatial distribution of forest structural parameters that are needed for more accurate models of energy, carbon, and water flux over regional, continental, and global scales. Thus, we examined the utility of hyperspectral data for the quantitative characterization of vertical wheat structure. Most remote sensing systems provided an image of the horizontal scope, but could not provide the vertical information on biochemical distribution in a crop canopy, thereby reducing the accuracy of measurement. Multi-angle data can increase the precision of forest parameters (Kimes,et al., 2006). The distribution of tissues in a crop canopy has certain characteristics - biochemical distribution is different because of transfer of matter during the growth stage. Leaves in a wheat canopy are composed of under, middle, upper layer and ear layers (Wang et al.,2004). The spectral characteristic differed among canopy leaves because of the different reflection and scatter, so their effect on canopy spectra was different (Wang et al., 2004). Various biochemical (foliar lignin and nitrogen) and biophysical factors influencing canopy reflectance signatures have been studied in previous works. Information on biochemical parameters is important and the multi-angle spectra which provide information on different directions can facilitate a more exact prediction of biochemical parameters. To date, there are no studies on the relative importance of vertical distribution of wheat leaves that determines canopy reflectance across the shortwave (350–2500nm) spectrum. The contribution of each leaf layer relative to all other factors has also not been adequately determined. Yet, it is the interaction of these factors, including their potential covariance or unique behavior, that must be understood if advances in remote sensing are to be achieved.
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In this study, the leaf slice method was used to characterize a wheat canopy, evaluate the spectral response of leaf vertical distribution in the canopy, determine the characteristics of spectral curve for different leaf layers and develop a methodology for predicting the biochemistry of the canopy.
2 Materials and Methods 2.1 Preliminary Experiment A field experiment was conducted in the Experimental Station of the Institute of Crop Science of the Chinese Academy of Agricultural Sciences, Beijing (39º57'55" N, 116º19'46" E) in the 2005-2006 growing season. The soil was a silt clay loam containing 1.16% organic matter, 42.6 mg kg-1alkali-hydrolysable N, 26.5 mg kg-1 available phosphorus and 139.4 mg kg-1 available potassium. Two winter wheat cultivars were used: Jingdong8, an erect leaf plant-type and Zhongyou9507, a lax leaf plant-type. Four N fertilizer (urea, 46%N ) treatments were set up with four randomized replications of each cultivar: N0, no N fertilization, N1, 150 kg hm-2 pure N fertilization, N2, 300 kg hm-2 (rationally fertilized), N3, 450 kg hm-2 (excessively fertilized). The N rates were applied in three splits at pre-sowing (50% of the total amount), reviving stage (25% of the total amount) and jointing stage (25% of the total amount). All the treatments were fertilized with the same amounts of P (P2O5, 144 kg hm-2) and K (K2O, 75 kg hm-2) at pre-sowing. The leaf slice method of wheat canopy: whole (plant) wheat samples 0.5m long and 0.8m wide were chosen; based on the vertical distribution of wheat canopy, the samples were measured off the whole wheat canopy (WWC), ear layer of canopy (ELC), inverse first leaves layer of canopy (ILLC-1), inverse second leaves layer of canopy(ILLC-2), inverse third leaves layers of canopy (ILLC-3) and inverse fourth leaves layer of canopy (ILLC-4). Canopy layers were severed with a scissors from the ear layer to lower layer (Fig. 3).
,
2.2 Measured Traits and Methods All canopy spectral measurements were taken from a height of 1.3 m above ground (the height of the wheat was 90 cm at maturity), under clear sky conditions between 10:00 and 14:00 (Beijing local time), using an ASD FieldSpec Pro spectrometer (Analytical Spectral Devices, Boulder, CO,USA) fitted with a 258 field of view fiber optics, operating in the 350–2500 nm spectral region with a sampling interval of 1.4 nm between 350 and 1050 nm and 2 nm between 1050 and 2500 nm and with spectral resolutions of 3 nm at 700 nm and10 nm at 1400 nm. A 40 cm ×40 cm BaSO4 calibration panel was used for calculation of reflectance. The spectra were measured with view angles of 0, 30,60,90,120, 150, and 180° to the line vertical to the wheat row using the Simple multi-angle spectral measurement equipment (Fig.1) after every layer was removed (N2 treatment). The model spectra were measured with a view angle of 0°
A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains
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using other treatments at ear layer (EL), upper leaves layer (ULL) and lower leaves layer(LLL)(Fig.2). Leaf samples from EL,ULL,LLL were taken almost synchronously with the spectral measurements. Measurements were conducted at jointing, heading, anthesis, milking and waxing stages. These samples were oven-dried at 70 and nitrogen content was determined by the Kjeldahl technique (Bremneretal.,1981) using a B-339 DistillationUnit (BUCHIAnalyticalLtd, Flawil, Switzerland). Wheat grain protein content estimated from the formula : Pro% =6.25 × Nitr (% ).
℃
sun
Ear layer
Upper layer
1/2H H
Lower layer
Fig. 1. Simple multi-angle spectral measurement equipment
1/2H
Fig. 2. Sketch of measured method by layer
2.3 Data Analysis The hyperspectral data were analyzed using the Matlab6.5 software and quantitative data were analyzed using an analysis of variance (ANOVA) procedure.
3 Results 3.1 The Spectral Curves Following Removal of Different Leaf Layers The lower leaves of the canopy changed the spectral reflectivity (Fig.3) with different view angles at 350-700nm, 800-1300nm and 1400-1800nm. This is important for pigment content within the visible wave band (350-700nm). The reflectivity of near infrared (800-1300nm) is influenced by canopy characteristics. The wavebands (1400-1800nm) provide information on the water content. In this paper, we analyzed the characteristics of visible (350-700nm) and near infrared (800-1300nm) wavebands.
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Jingdong8
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Fig. 3. Spectra of removing the forth leaf layer at different angles for Jingdong8 and Zhongyou9507 wheat
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Fig. 4. Spectra of removing different leaf layers at 60°angles for Jingdong8 and Zhongyou9507
Comparing the direction spectral characteristic of the two wheat canopies, the spectral response of Jingdong8 with different view angles was more significant than that of Zhongyou9507 at visible and near infrared wavebands; the max reflectivity of Jingdong8 was 31% higher than that of Zhongyou9507 at 350-700nm and 22.4% higher at 800-1300nm. The spectral curve of doing away with different leaves at the 60° view angle showed that the leaf influenced the curve of visible and near infrared wavebands (Fig.4). The change for Jingdong8 was more significant than for Zhongyou9507; the spectral reflectivity of Jingdong8 was 11.2% higher than that of Zhongyou9507 at 350-700nm and 26.8% higher at 800-1300nm. To further analyze the relation between canopy spectra and leaves, we selected six spectral reflectivities at 450, 550, 670, 980, 1090, 1200nm. 3.2 Analysis of Spectral Reflectivity of Leaf Layers at Different View Angles As shown in Fig.5, for Jingdong8, the spectral reflectivity of the whole canopy was similar with the leaf layer removal treatment, ILLC-4; doing away with ELC and ILLC-1 reduced the reflectivity. The changes in reflectivity at 550nm were more
A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains
WWC
21
ELC
ILLC-1
ILLC-2
Fig. 5. Spectral characteristics following removal of different leaf layers in Jingdong8
obvious than at 450 and 670nm. In visible wave bands, changes were evident for 980, 1090, 1200nm in near infrared wave bands. At different view angles, the reflectivity of the 90° view angle was the lowest and with increasing distance from the vertical measurement, the reflectivity increased, especially in visible wave bands than in near infrared. The reflectivity changes due to ILLC-1 and ELC were more obvious than those of other leaf layers. The reflectivity changes due to LLC-3 at 1090nm were 8.8% at 0° view angle and 48.6% for ILLC-1. At 90° view angle, the changes were 5.6 and 40.7%; at 30°, they were 12.9 and 27.7% and at 60° they were 12.2 and 34%, respectively. The change was less pronounced at the 180, 150 and 120° view angles. Compared to the 90° view angle, the reflectivity at 30 and 60° had more information on the lower leaves, which were
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important for reflectivity of the canopy. The reflectivity at 0° contained very important information on upper leaves. The canopy spectral reflectivity of Zhongyou9507 was lower than that of Jingdong8 (Fig.6) at1090nm; the reflectivity due to ILLC-3 at 0° view angle changed 4.4%, while that due to ILLC-1 changed14.7%; at 90° view angle, the changes were 5.9 and 46.8%; at 30°, they were 16.9 and 44.4% and at 60° they were 16.8 and 41.2%. Compared with the traditional 90° view angle, the lower leaves were important for canopy spectra at 30 and 60° view angles; the upper leaves were important at 0° view angle although the upper leaves of Zhongyou9507 had less influence on canopy spectra than those of Jingdong8.
WWC
ILLC-1
ILLC-3
ELC
ILLC-2
ILLC-4
Fig. 6. Spectral characteristics following removal of different leaf layers in Zhongyou9507
A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains
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3.3 Analysis of Variance (ANOVA) of Spectral Reflectivity for Different Leaf Layers The ANOVA of mean reflectivities across six wavelengths showed that the reflectivity of Jingdong8 was lower than that of Zhongyou9507 (Table 1). For Jingdong8, the response of canopy spectra due to ILLC-1 and ELC were significant at the 0° view angle; at 30° as for 60°, the effects of ELC, ILLC-1, ILLC-2 and ILLC-3 were significant; at 90°, the ELC and ILLC-1 were important and at 120, 150 and 180° view angles, the ELC and ILLC-1 were significant. The ELC and ILLC-1 were important for canopy spectra and the influence of lower leaves were less. For the view angles of 0°, 90°, 120°, 150°, 180°), the under leaves were less influential; at 30 and 60°, the response of lower leaves were significant. The canopy spectral responses of different leaves for Zhongyou9507 differed from that of Jingdong8; at 0 and 90° view angles, the ELC and ILLC-1 effects were significant at 30 and 60°, the ELC, ILLC-1, ILLC-2 effects were significant. At the same view angle, the ELC and ILLC-1 were more important than the lower leaves. The spectral response of lower leaves was related to the view angle. With vertical and horizontal measurements, the influence of lower leaves were less than that of other view angles. Table 1. Canopy spectral characteristic of different leaf layers of Jingdong8 and Zhongyou9507
Average value Angles°
Treatments
0
WWC ILLC-3 ILLC-4 ILLC-2 ILLC-1 ELC WWC ILLC-4 ILLC-3 ILLC-2 ILLC-1 ELC WWC ILLC-4 ILLC-3 ILLC-2 ILLC-1 ELC
30
60
0.2254 0.2110 0.2046 0.1974 0.1690 0.1508 0.2265 0.2196 0.1951 0.1886 0.1591 0.1487 0.2064 0.2021 0.1816 0.1645 0.1412 0.1225
Jingdong8 a A a A a AB ab AB bc BC c C a A ab A bc AB c AB d BC d C a A a A ab AB bc ABC bc BC c C
Zhongyou9507 0.1657 a 0.1643 a 0.1662 a 0.1573 a 0.1354 b 0.1308 b 0.1713 a 0.1646 a 0.1619 ab 0.1398 bc 0.1276 cd 0.1143 d 0.1784 a 0.1553 ab 0.1503 ab 0.1323 bc 0.1052 c 0.0974 c
A A A A B B A AB AB BC C C A A AB ABC BC C
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Table 1. (continued)
Average value Angles°
Treatments
90
WWC ILLC-4 ILLC-3 ILLC-2 ELC ILLC-1 WWC ILLC-4 ILLC-3 ILLC-2 ILLC-1 ELC ILLC-4 ILLC-3 ILLC-2 WWC ILLC-1 ELC WWC ILLC-4 ILLC-3 ILLC-2 ILLC-1 ELC
120
150
180
0.1588 0.1726 0.1451 0.1292 0.1081 0.1040 0.1645 0.1642 0.1511 0.1341 0.1139 0.1051 0.1734 0.1637 0.1547 0.1454 0.1325 0.1166 0.2254 0.1879 0.1883 0.1725 0.1388 0.1360
Jingdong8 a A a AB ab AB ab AB b B b B a A a A ab AB abc AB bc AB c B a A ab AB abc AB abc ABC cd BC d C a A ab AB ab ABC bc BC c BC c C
Zhongyou9507 0.1766 a 0.1657 a 0.1532 abc 0.1276 abcd 0.1137 bcd 0.1084 d 0.1765 a 0.1692 ab 0.1616 abc 0.1432 bcd 0.1255 d 0.1325 cd 0.1679 ab 0.1692 a 0.1568 bc 0.1672 ab 0.1515 c 0.1555 c 0.1678 a 0.1599 a 0.1555 a 0.1464 a 0.1461 b 0.1537 b
A AB AB AB B B A AB AB AB AB B A A A AB AB B A A A A B B
Note: Means followed by different lower case letters differ significantly at P< 0.05; those followed by different upper case letters differ significantly at P<0.01.
3.4 Correlation of Spectral Parameters of Leaf Layers with Leaf Nitrogen Content (LNC)
△
The correlation between canopy spectral parameters, spectral grads and corresponding nitrogen content in different leaf layers (Table 2) was significant between RVI[670, 890] and leaf layer grads at the flowering stage for Jingdong8 and milky stage for Zhongyou9507.
A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains
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Table 2. Correlation coefficients between nitrogen contents at different layers and spectral characteristics ( SC ) Growth stage
Cultivar
content
680nm
NDVI [857,1210]
PRI
PPR
(570,531)
(550,540)
OSAVI
RVI [670,890]
ULNC
-0.2058
0.6835*
0.1929
-0.4270
-0.6850*
LLNC
-0.2016
0.6437*
0.2082
-0.3300
-0.5669
0.5361
LNC
-0.2779
0.6431*
0.5443
-0.5240
-0.3256
0.7710**
Zhongyou
ULNC
0.0627
-0.2781
0.0508
-0.6561*
-0.0322
0.6171*
9507
LLNC
0.5923
-0.0223
0.2141
-0.5069
0.1373
0.5710
LNC
-0.2234
-0.4238
-0.6304*
-0.4990
-0.1748
-0.6335*
ULNC
0.3290
0.5788
0.6957*
-0.5719
0.4431
0.5831
LLNC
0.3656
0.5690
0.4514
-0.5913
0.4368
0.6097*
LNC
0.5610
0.3882
-0.4454
-0.3284
-0.5557
0.6627*
Zhongyou
ULNC
0.2041
0.1279
0.1432
-0.5355
0.2822
0.4570
9507
LLNC
0.4674
-0.4111
-0.5394
0.6751*
-0.2721
0.5118
LNC
-0.1453
-0.5269
-0.6252*
-0.4591
-0.1190
-0.7888**
Jingdong8 Anrhesis
Milky
LSCP
nitrogen
Jingdong8
ripe
0.6900*
* and ** : significant correlations at 0.05 and 0.01 probability levels, respectively. ULNC: upper layer nitrogen content; LLNC: lower layer nitrogen content;
△LNC: the difference between
ULNC and LLNC. LSCP: spectral characteristics of leaf layers. NDVI: normalized difference vegetation index; PRI: pigment ratio index; PPR: plant pigment ratio; OSAVI: optical soil adjusted index; RVI: ratio of vegetation index.
3.5 Model Relating Grads of Spectral Parameter and Those of Nitrogen Content across Leaf Layers The following models were developed from the siginificant correlations between grads of spectral parameter and those of nitrogen content in leaf layers: Flowering stage of Jingdong8:
△LNC (%) = 35.2842△RVI+0.3822 R2=0.8267**, n=24
(1)
Milking stage of Zhongyou9507:
△LNC (%) = -8.0692△RVI+1.5506 R2=0.8099**, n=24
(2)
3.6 Leaf Layer Spectral Model for Protein Content in Wheat Grains A prediction model for GPC based on spectra of leaf layers was developed as follows: a) Jingdong8 at the flowering stage:
△RVI + 15.6975
GPC (%) = 12.0168 2
R =0.7727**, n=24
(3)
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b) Zhongyou9507 at the milk stage: GPC (%)=-8.9028 2
△RVI+18.7397
R =0.7838**, n=24
(4)
The conventional spectral model using 90°view angle was also developed as follows: a) Jingdong8 at the flowering stage: GPC (%) = 11.98RVI +16.71 R2=0.6537**, n=24
(5)
b) Zhongyou9507 at the milk stage: GPC (%) = 19.21RVI +13.59 R2=0.6659**, n=24
(6)
The determinant coefficients, R2 of models (5) and (6) were 18 and 17% higher than those of models (3) and (4), hence, the predicted GPC model of leaf layer spectral was better. 3.7 Validation of the Predicted GPC Model of Leaf Layer Spectra
⌟ᅮؐ0HDVXUHGYDOXH
⌟ᅮؐ0HDVXUHGYDOXH
The root mean square error (RMSE) was used to test the reliability and estimation accuracy of these models for grain protein content. The RMSE of Jingdong8 was 0.7500 while that of Zhongyou9507 was 0.6461. The determinant coefficients, R2 between measured and estimated grain protein contents were 0.7467 and 0.7599, respectively (Fig. 7). These result indicated that prediction of grain protein using the leaf layer spectral model is reliable.
5
Jingdong 8
5
Zhongyou 9507
乘⌟ؐ(VWLPDWHGYDOXH
乘⌟ؐ(VWLPDWHGYDOXH
Fig. 7. Estimated and measured grain protein contents (GPC) in Jingdong 8 and Zhongyou 9507
4 Conclusions The crop canopy has a three-dimensional structure whose characteristics are determined by species composition and the three-dimensional distribution of leaves. The biochemical content has some regulatory role in the distribution of the canopy space. The horizontal
A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains
27
radiation balances are likely to occur if the internal variability of derived surface products, the typical distances that photons may travel horizontally within such 3-D media extend to spatial scales that are similar to or larger than those of the measuring sensor In order to maintain the energy balance of the overal forest domain, lacal canopy volumes with rather large positive net horizontal fluxes must also exist,thus underscoring the importance of properly locating local flux measurement equipment(Jean-Luc Widlowski, 2006). The more accurate modeling of energy are required for remotely measure the vertical and spatial distribution of forest structure. The potential of using a multi-angle spectral sensor to predict forest vertical structure were researched, the results showed the multi-angle spectral provided a relatively direct measure of vertical structure(D.S.Kimes 2006). The anisotropic scattering of both the vegetation canopy and the background is taken into consideration in a two-layer model of the bidirectional reflectance of homogeneous vegetation canopies(S.Liangrocapart, 2002). In this study, two wheat varieties differing in plant-type were studied using the leaf layer slice method by analyzing the spectral changes for different leaf layers at different view angles in the plane of vertical wheat line. We noted that: (1) The spectral characteristics varied in 300-700nm, 800-1300nm and 1400-1800nm wave bands because of removal of leaf layers and differences in view angle. The change in the visible wave bands was less than that in near infrared wave bands and that in Jingdong8 was less than that in Zhongyou9507. (2) Compared with the traditional 90° view angle, the spectral information of under leaves were more at 30 and 60° than other view angles; for upper leaves the information was more at 0° view angle. The spectral influence of upper leaves of Zhongyou9507 at 0° view angle was less than that of Jingdong8. The upper leaves of the lax-leafed wheat captured much radiation because of their horizontal orientation, the proportion of upward leaves was bigger than that of downwards leaves. In contrast, the radiation characteristics were complicated in the erect leaf plant-type. (3) The predicted GPC model by leaf layer spectra using 0° view angle were feasible, the RMSE was 0.7500 for Jingdong8 and 0.6461 for Zhongyou9507. The determinant coefficients, R2 between measured and estimated grain protein contents were 0.7467 and 0.7599. Thus, the leaf layer model would be reliable for predicting grain protein content. In precision agriculture, it is important to accurately measure the state of a crop’s growth using remote sensing techniques. In this study, we analyzed the canopy spectral characteristics of two wheat types and observed that canopy spectra were influenced by leaf layers and view angles; the spectral response of under leaves varied with different view angles. A quantitative study of different leaf layers and their spectra is needed for precise crop management. Since results were obtained only in Peking region, more experiments should done in other regions.
Acknowledgments This work was supported with grants (2006AA10Z207, 2006AA10A302) from the National High Tech R&D Program and (30760109) from the National Natural Science Fundation of China and (2007BAH12B02) National Key Technology R&D Program.
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References [1] Dorigo, W.A., Zurita-Milla, R., de Wit, A.J.W., Brazile, J., Singh, R., Schaepman, M.E.: A review on reflective remote sensing and data assimilation techniques for enhanced agroecosystem modeling. International Journal of Applied Earth Observation and Geoinformation 5, 1–29 (2006) [2] Kimes, D.S., Ranson, K.J., Sun, G., Blair, J.B.: Predicting lidar measured forest vertical structure from multi-angle spectral data. Remote Sensing of Environment 100, 503–511 (2006) [3] Sobrino, J.A., Jiménez-Muñoz, J.C., Verhoef, W.: Canopy directional emissivity: comparison between models. Remote Sensing of Environment 99, 304–314 (2005) [4] O’Neill, A.L., Kupiec, J.A., Curran, P.J.: Biochemical and reflectance variation throughout a sitka spruce canopy. Remote Sensing of Environment 80, 134–142 (2002) [5] Wang, Z.J., Wang, J.H., Huang, W.J., Ma, Z.H., Wang, B.H., Zhao, C.J., Zhao, M.: The properties of temporal and spatial distributions relationship between leaf nitrogen and grain quality leaf nitrogen and the winter wheat. Acta Agronomica Sinica 7, 700–707 (2004) (in Chinese) [6] Wang, J.H., Wang, Z.J., Huang, W.J., Ma, Z.H., Liu, L.Y., Zhao, C.J.: The vertical distribution characteristic and spectral response of canopy nitrogen in different layer of winter wheat. Journal of Remote Sensing 7, 309–315 (2004) (in Chinese) [7] Johnson, L.F.: Nitrogen influence on fresh-leaf NIR spectra. Remote Sensing of Environment 78, 314–320 (2001) [8] Serrano, L., Peñuelas, J., Ustin, S.L.: Remote sensing of nitrogen and lignin in mediterranean vegetation from AVIRIS data: decomposing biochemical from structural signals. Remote Sensing of Environment 81, 355–364 (2002) [9] Cho, M.A., Skidmore, A.K.: A new technique for extracting the red edge position from hyperspectral data: The linear extrapolation method. Remote Sensing of Environment 101, 181–193 (2006) [10] Li, Y.X., Zhu, Y., Tian, Y.C., Yao, X., Qin, X.D., Cao, W.X.: Quantitative relationship between leaf nitrogen accumulation and canopy reflectance spectra in wheat. Acta Agronomica Sinica 2, 203–209 (2006) (in Chinese) [11] Xue, L.H., Cao, W.X., Luo, W.H., Jiang, D., Meng, Y.L., Zhu, Y.: Diagnosis of nitrogen status in rice leaves with the canopy spectral reflectance. Scientia Agricultura Sinica 36(7), 807–812 (2003) (in Chinese) [12] Lu, Y.L., Wang, J.H., Li, S.K., Xie, R.Z., Gao, S.J., Ma, D.L.: Identification of wheat canopy structure using hyperspectral data. Scientia Agricultura Sinica 4(9), 668–672 (2005) [13] Bai, J.H., Li, S.K., Wang, K.R., Zhang, X.J., Xiao, C.H., Sui, X.Y.: The response of canopy reflectance spectrum for the cotton LAI and LAI inversion. Scientia Agricultura Sinica 40(1), 63–69 (2007) (in Chinese) [14] Liu, W.-d., Xiang, Y.-q., Zheng, L.-f., Tong, Q.-x., Wu, C.-s.: Relationships between rice LAI, CH.D and hyperspectra data. Journal of Remote Sensing 4(4), 279–283 (2000) (in Chinese) [15] Wu, C.-s., Xianh, Y.-q., Zheng, L.-f., Tong, Q.-x.: Estimating chlorophyll density of crop canopies by using hyperspectral data. Journal of Remote Sensing 4(3), 228–232 (2000) (in Chinese) [16] Zhang, X., Liu, L.-y., Zhao, C.-j., Zhang, B.: Estimating wheat nitrogen concentration with high spectral resolution image. Journal of Remote Sensing 7(3), 176–181 (2003)
A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains
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[17] Widlowski, J.-L., Pinty, B., Lavergne, T., Verstraete, M.M., Gobron, N.: Horizontal radiation transport in 3-D forest canopies at multiple spatial resolutions: Simulated impact on canopy absorption. Remote Sensing of Environment 103, 379–397 (2006) [18] Walter-Shea, E.A., Privette, J., Cornell, D., Mesarch, M.A., Hays, C.J.: Relations between directional spectral vegetation indices and leaf area and absorbed radiation in alfalfa1. Remote Sensing of Environment 61, 16–177 (1997) [19] Kuusk, A., Nilson, T.: A directional multispectral forest reflectance model. Remote Sensing of Environment 72, 244–252 (2000) [20] Gemmell, F., McDonald, A.J.: View zenith angle effects on the forest information content of three spectral indices. Remote Sensing of Environment 72, 139–158 (2000) [21] Bousquet, L., Lachérade, S., Jacquemoud, S., Moya, I.: Leaf BRDF measurements and model for specular and diffuse components differentiation. Remote Sensing of Environment 98, 201–211 (2005) [22] Gao, F., Zhu, Q.J.: The advance in multi-angle remote sensing of vegetation canopy. Scientia Geographica Sinica 11, 346–355 (1997) [23] Lu, Y.L., Li, S.K., Wang, K.R., Xie, R.Z., Gao, S.J., Wang, G.: Prediction of grain protein content using ear layer spectral reflectance data. Acta Agron Sinica 2(32), 232–236 (2006) [24] Lu, Y.L., Li, S.K., Wang, J.H.: Prediction of grain protein content of wheat based on the ear level spectrum. In: 25th Anniversay IGARSS (International Geoscience and Remote Sensing Symposium) 2005, Seoul Korea, July 25-29 (2005) [25] Xiao, C.H., Li, S.K., Wang, K.R., Lu, Y.L., Xie, R.Z., Gao, S.J.: Prediction canopy leaf nitrogen content of winter wheat based on reflectance spectra in different directions. Acta Agron Sinica 33(7), 1141–1145 (2007)
A New Color Information Entropy Retrieval Method for Pathological Cell Image Xiangang Jiang1, Qing Liang2, and Tao Shen2 1
Information Engineering School of East China, Jiaotong University, Nanchang, Jiangxi, China (330013)
[email protected] 2 Basic Science School of East China Jiaotong University, Nanchang, Jiangxi, China (330013)
[email protected]
Abstract. For the distribution characteristics in a slice of pathological cell image, the system transforms them into the characteristic vector by quantization and clustering in HSV color model, it promotes the concerned isolated pixel color description into the color feature of its neighborhood region color histogram. By choosing appropriate neighborhood window size, it uses color information entropy method to gain efficient primary classification of gastric slice image and the similar retrieval results from the sample library images. Experiments show that this method has a better image classification and retrieval result. Keywords: Mutual information, Histogram, Color moments, Information entropy, CBIR.
1 Introduction With the unceasing development of the modern imaging technology and information processing technology, the image numbers in medical scopes are more and more. By the submitting image, how to use the existing technical methods to retrieve and classify the comparative images from the qualitative sample library is crucial, which is used for clinical diagnosis and contrast, it is becoming one of the research task for efficient medical diagnosis. In allusion to the pathological cell images, this paper makes use of neighborhood color moment histogram to extract color information and utilizes the theory of information entropy to realize shortcut image retrieval.
2 Shannon Mutual Information Representation of mutual information derives from information theory, which is the measure of correlations of two variables. If use H to represent entropy, I represent an image, a represent the color values of an image, suppose the probability density D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 30–38, 2011. © IFIP International Federation for Information Processing 2011
A New Color Information Entropy Retrieval Method for Pathological Cell Image
function of
31
I is pi = p(a = i), i = 1, 2,..., m , then the Shannon Entropy of I is
H (I ) :
1 pi (i)
H ( I ) = ∑ pi (i) × log i∈I
Where as
(1)
pi (i) = 0 , supplementary definition: pi (i) × log
To two images
1 1 = 0 , as: lim+ p log = 0 . p → 0 p pi (i)
I1 and I 2 ,their color values are described by 256 kinds of vectors,
their joint entropy is defined as: H ( I1 , I 2 ) =
255 255
1
∑ ∑ P ( i , j ) log P ( i , j ) i=0 j=0
ij
(2)
ij
Where Pij (i, j ) is the representation of color joint probability density distribution. Their Shannon mutual information I ( I1 , I 2 ) =
I ( I1 , I 2 ) is defined as:
255 255
∑ ∑ P ( i , j ) log i=0 j=0
ij
Pij ( i , j )
(3)
p i (i ) p j ( j )
= H ( I1 ) + H ( I 2 ) − H ( I1 , I 2 ) Where
pi (i ), p j ( j ) is the color probability density distribution of I1 and I 2 , Pij (i, j ) is
color joint probability density distribution, H ( I1 , I 2 ) is Shannon joint entropy. In the image registration and retrieval, Shannon mutual information is a representation of information amount of interactivity implicated in two images. When I ( I1 , I 2 ) = 0 , it shows that
I1 and I 2 are independent mutually, if the value of I ( I1 , I 2 ) is bigger,
which means the similarity is higher in the color distribution of two images.
3 Color Space Conversions Among many color models, RGB models can be better matched with the fact that people can fiercely percept the tricolor such as R, G, and B, furthermore, it is easy to express in software developing language. However, RGB color model is not accorded to the human beings’ visual perception dealing with distinguishing color similarity. Therefore, many researchers put forward some other color models accorded to visual perception, such as HIS, HSV, Luv, Lab and so on. HSV is more commonly used, its three-component separately represent Hue, Saturation and Value. This paper uses the HSV color model to define color vector. Firstly the transfer formula between RGB and HSV is given as follows. Suppose a pixel values are r, g, and b in RGB color model, in
32
X. Jiang, Q. Liang, and T. Shen
which r , g , b ∈ [0...255] , then the transformed values (h,s and v) in HSV color model are calculated as follows follows: r' =
Then
: Suppose v' = max(r , g , b)
and define
r ' , g ' , b ' as
v'−r v'−g v'−b , g' = , b' = v'− min(r, g, b) v'− min(r, g, b) v'− min(r, g, b)
v = v ' 255 ,
s = (v ' − min(r , g , b)) v ' ⎧5 + b , r = max(r , g , b) ⎪ ' ⎪1 − g , r = max(r , g , b) ⎪1 + r ' , g = max(r , g , b) ⎪ h' = ⎨ ' ⎪3 − b , g = max( r, g , b) ⎪3 + g ' , b = max(r , g , b) ⎪ ⎪⎩5 − r ' , else '
(4)
and g = min( r , g , b) and b = min( r , g , b) and b = min( r , g , b) and g = min( r , g , b) and r = min(r , g , b)
h = 60 × h'
Where r ' , g ' , b ' ∈ [0,1] , h ∈ [0, 360] , s, v ∈ [0,1] . In allusion to Fig.1, make use of the transfer formula above firstly, in the HSV color model h component is mainly concentrated in range [0,100] and [300, 360] , but the distribution of s and v component are relative uniformity. According to the characteristics, it will use the method in reference [1] for quantization and clustering of colors. Suppose the color vectors of pixel (i , j ) are pij ∈ [0, 255] , which will be used for image retrieval features.
4 Neighborhood Color Moment Mutual Information 4.1 Description of Color Moment A. single pixel color moment Another method of expressing and analyzing color distribution is the calculation of color moment. The mathematical foundation of this method being reasonable is that any color distribution can be represented by its moments. In addition, as the color distribution information is mainly concentrated in lower-order-moments, so it is enough to express the color distribution of an image only by its first moment, second moment and third moment of colors. Comparing to color histogram, this method is good at the aspect that no needs to quantize the color characteristics. The lower-order-moments of color are expressed in mathematics as follows:
A New Color Information Entropy Retrieval Method for Pathological Cell Image
⎧ 1 N μ = ⎪ ∑ pj N A j =1 ⎪ 1 ⎪⎪ 1 N 2 2 p μ − ( ) ) ⎨σ = ( ∑ j N A j =1 ⎪ 1 ⎪ 1 N 3 3 ⎪s = ( p μ − ( ) ) ∑ j N A j =1 ⎪⎩ Where
33
(5)
p j is the definition of color value of pixel j , N A represents the whole number
of pixels in an image. B. Neighborhood color moment As the ability to distinguish based on lower-order-moments of single pixel color is suboptimal, it doesn’t make comprehensive consideration to its local color distribution of pixels. So in this paper, it considers the neighborhood of pixels as an analysis unit to calculate the corresponding color moments and it concerns the local color spatial distribution information reflected by pre-three lower-order-moments in a pixel’s around window. Suppose pij is the color value of concerned pixel (i, j ) , which is quantified and clustered in HSV color model, then its first, second and third order central moment are as follows: N −1 M −1 i+ j+ ⎧ 2 2 1 ⎪μ M = pmn ∑ ∑ ⎪ ij M × N m = i − N −1 n = j − M − 1 ⎪ 2 2 ⎪ N −1 M −1 i+ j+ 1 2 2 ⎪⎪ M 1 ( p m n −u ijM ) 2 ] 2 ⎨ σ ij = [ ∑ ∑ M × N m = i − N −1 n = j − M −1 ⎪ 2 2 ⎪ N −1 M −1 i + j + ⎪ 1 2 2 ⎪sM = [ 1 ( p m n −u ijM ) 3 ] 3 ∑ ∑ ij ⎪ M × N m = i − N −1 n = j − M −1 ⎪⎩ 2 2
(6)
The moving window is respectively selected as 3 × 3 , 5 × 5 , 7 × 7 , the range of numerical values in extraction of three lower-order-moments of all pixels (i, j ) is limited in [0, 255] . In allusion to each pixel in an image, it makes use of quantization and clustering color histogram of image referred above to obtain nine neighborhood color moments, (for a window 3 × 3 ), which are described in the region [0, 255] just by rounding all float numbers. It makes the global statistics and normalization to the entire image and gets normalization histograms of nine neighborhood lower-order central moments.Fig.2 shows as: the normalization histograms of the first, second and third order central moment in 3 × 3 neighborhood window, where the red curve represents H ( μ 3 ) , the green one represents H (σ 3 ) , the blue one represents
H ( s 3 ) and the black one represents the color histogram by quantified and clustered color vectors.
34
X. Jiang, Q. Liang, and T. Shen
Fig. 1. Pathological cell image
Fig. 2. The compared histograms of the first, second, third order moment and the entire image’s quantified and clustered color vectors in the 3 × 3 neighborhood window
To 256 colors in the picture, it can make a statistics separately for the frequency of the first, second and third order central moment in an image, suppose the probability distribution of the k order central moment is qik , then:
qik = N ik N A Where
(7)
N ik represents the occurrence times of the k order color central moment, N A
is the representation of all pixel numbers in an image. Define the color joint probability density distribution of the k order central moment of two images by the same methods, which is supposed as qijk , where i, j = 0,1,...255 , k = 1, 2,3 . 4.2 The Calculation of Mutual Information of Each Order Multi-neighborhood Color Moments In order to define the mutual information of multi-neighborhood color moments, instead qik , qijk of pi (i ) , Pij (i, j ) to obtain the definition of entropy and mutual information of multi-neighborhood color moments. Then the definition of entropy of each order multi-neighborhood color moments is: H(I ) = ∑qik (i) × log i∈I
1 qik (i)
(k = 1,2,3)
(8)
The mutual information of each order multi-neighborhood color moments between two images I1 , I 2 is defined as: 255 255
qijk (i, j)
i=0 j =0
qik (i)q jk ( j)
I ( I1, I2 ) = ∑∑qijk (i, j)log
= H ( I1 ) + H ( I 2 ) − H ( I1 , I 2 )
(k = 1,2,3)
(9)
A New Color Information Entropy Retrieval Method for Pathological Cell Image
35
In all, the classification and retrieval for the pathological cell images can be achieved not only by the mutual information of each order multi-neighborhood color moments, but also by the mutual information of synthesis vector normalized by each order neighborhood color moment. 4.3 Similarity Definition According to the theory of mutual information, the similarity of two images is defined as follows:
S ( I1, I 2 ) =
I ( I1 , I 2 ) H ( I1 ) + H ( I 2 )
(10)
Proof, 0 ≤ S ( I1 , I 2 ) ≤ 1 . First, because of nonnegativity of mutual information and the definition of information entropy referred, it shows that I ( I1 , I 2 ) ≥ 0 , H ( I1 ) ≥ 0 , H ( I 2 ) ≥ 0 ,each term of numerator and denominator in formula(10) is nonnegative, therefore, S ( I1 , I 2 ) ≥ 0 . Next prove S(I1, I2 ) ≤ 1, Because of the definition of color entropy, it shows H ( I1 , I 2 ) ≥ 0 and it can be easy to know I ( I1 , I 2 ) ≤ H ( I1 ) + H ( I1 ) according to formula(9), and then S ( I1 , I 2 ) ≤ 1 .So, on the basis of the analysis above, The function S ( I1 , I 2 ) satisfies the definition of similarity, it can be used to describe the color similarity measure of two images.
5 The Experimental Analysis and Conclusions In allusion to three hundred images downloaded from www.phoenixpeptide.com &www.microscopyu.com, sixty cancer images are included and the other ones are all normal. It clearly shows that the main distinctions between cancer images and normal ones are the differences of their color distribution by comparing and analyzing their information entropy of color moment. In the experiment, it employs a new color information entropy retrieval method which promotes the concerned isolated pixel color description into the color feature of its neighborhood region color histogram and makes use of the theory of information entropy to gain the retrieval and primary classification to a further compared classification between the key image and the qualitative sample library. There are three test patterns designed in this experiment the first one do an experiment of retrieval based on color mutual information of single pixel; the second one do an experiment of retrieval by making use of the isolated mutual information of the pre-three order color moment in window size of 3 × 3 , 5 × 5 , 7 × 7 separately; the third one: do an experiment of retrieval based on the mutual information of the normalized characteristics vector of the three order color moments. This system uses the method called “based on the key image” that it gives a submitting image and finds out the similar images from the sample image library, while
36
X. Jiang, Q. Liang, and T. Shen
a retrieval process finished, the system will return the most similar eight images from the qualitative sample image library to achieve the primary qualitative analysis between the submitting image and the qualitative images from the sample image library. This experiment adopts image shown in Fig.1 as the key image. This system implements the retrieval and classification of stomach cell images in a development environment of Windows XP by Delphi 7.0, precision is used for the estimation of the experimental efficiency and it is defined as:
Pr ecision =
a a+b
(11)
Where ' a ' represents the similar image numbers with the key image retrieved from the sample image library; ' b ' represents the image numbers of dissimilarity. In allusion to the image in Fig.1, it uses the method of the mutual information of the single pixel to achieve retrieval and obtain the most similar eight images are showed in Fig.3, Fig.4 shows the retrieval results by employing the method based on the mutual information of the first order color moment in the window size of 5 × 5 . Each color mutual information retrieval efficiency are showed as the table 1.
Fig. 3. The retrieval result by the method based on mutual information of a single pixel
Fig. 4. The retrieval result by the method based on mutual information of the first order color moment with a window size of 5 × 5
A New Color Information Entropy Retrieval Method for Pathological Cell Image
37
Table 1. The comparison of each method of color mutual information
Retrieval method Size of window
Types of color mutual information Single pixel color The first order color moment The second order color moment
3*3
5*5
Precision of Consuming time of using three Consuming using three order order color time(ms) color moment moment synthesis ms synthesis (%)
( )
80.65
6141
88.25
8828
90.19
8875 91.23
18012
The third order color moment
90.19
9234
The first order color moment
87.88
8625
The second order color moment The third order color moment The first order color moment
7*7
Precision (%)
The second order color moment The third order color moment
91.30
92.56
12375
92.65
13025
89.31
8968
92.45
92.86
93.17
16875
26412
36247
17400
From the above table, we know that the retrieval efficiencies of the methods of mutual information of each order color moment regarding neighborhood region are higher than the one based on the single pixel, meanwhile, the retrieval efficiencies relative to the color moment order trend to be positive growth, the way based on synthesis mutual information of each order neighborhood color moment has the best precision. At the point of consuming-time, the method of each color moment is longer relatively to the one based on the single pixel and it is in direct proportion to the order. In allusion to the retrieval method of mutual information of color moment in different
38
X. Jiang, Q. Liang, and T. Shen
neighborhood sizes, while the geometric size of each tissue in an image is small, it will be better to choose the smaller window neighborhood, which has a high retrieval efficiency and low consuming-time; otherwise select a bigger neighborhood window to the bigger tissue in an image, it would avoid the characteristic fuzzy of each tissue in an image by adopting a flexible window size.
References [1] Chen, Q., Tai, X., Ba, T.: Gastroscope image retrieval based on histogram of neighborhood color moments. J. Computer Engineering and Applications 44(11), 205–208 (2008) [2] Wang, Y.: Expression on the Basis of the Timber Surface Color Characteristic of the Histogram and Color Moment Method. J. Forestry Science & Technology 31(5), 56–58 (2006) [3] Dong, W., Zhou, M., Geng, G.: Image Retrieval Technique Based on combined features. J. Computer Applications and Software 22(10), 34–36 (2005) [4] Fan, Z., Liu, E., Xu, B.: Application of Mutual Information in Image Retrieval. J. Journal of University of Electronic Science and Technology of China 36(6), 1311–1314 (2007) [5] Huang, X., Chen, G.: Color image retrieval based on color and texture. J. Popular Science & Technology 126(2), 13–15 (2010)
A New Palm-Print Image Feature Extraction Method Based on Wavelet Transform and Principal Component Analysis Jia wei Li and Ming Sun* China Agriculture University, Beijing China
[email protected]
Abstract. In recent years, as one of the biometric identification technology, palm-print identification has received many reseachers’ attention. To solve the key problem of palm-print recognition -- feature extraction, we propose a new method, which based on wavelet transform and principal component analysis. In general, we use wavelet transform to deal with palm print images and extract high-dimensional wavelet energy features, then reduce the dimensionality of high-dimensional wavelet energy features through principal component analysis, and remain the original feature energy maximally. The features extracted by this method not only reflect palm-print images’ information maximally, but also achieve the goal of data dimensionality reduction. Experiments show, the correct recognition rates of new method are much higher than those traditional methods such as LDA [1], PCA [2], 2DPCA [3], ICA [4] and so on. Keywords: Palm-print Recognition, feature extraction, wavelet transform, Principal component analysis.
1 Introduction Recently, researchers have done much research on palm-print recognition technology, and proposed many methods of palm-print feature extractions. In these methods, there are mainly methods which based on the structure of feature extraction, such as pointfeature and line-feature; the time-frequency [5] analysis of feature extraction, such as fourier transform, wavelet transform [6,7]; the subspace method of feature extraction, such as PCA,ICA. However, the method effect of feature extraction which based on the point-feature and line-feature of palm-print will be unsatisfied in the situation of low resolution of palm-print images. Similarly, the feature extraction which based on Fourier transform gets high dimensional data which is not advantaged to the real time recognition algorithm. Therefore, we propose a new method which based on wavelet transform and PCA to extract features of palm-print more effective. *
Author for correspondence:
[email protected]
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 39–46, 2011. © IFIP International Federation for Information Processing 2011
40
J.w. Li and M. Sun
2 Two-Dimensional Wavelet Transform Firstly, we use edge detect algorithm and corner detect algorithm to locate the ROI (region of interest) of palm-print .Figure 1 shows the original image, the edge of palm, the corner of palm edge and ROI of palm-print. As we know, the palm-print image is a kind of image which is similar to the texture of cycle image, different regions of the ridge orientation and spatial frequency represent the inherent characteristics of palm-print, so we use 2-D wavelet transform to decompose the image which provide the spatial and frequency domain positioning properties and separate the energy characteristics of multi-resolution palm-print image. Let I ( x, y ) denote the ROI of palm-print, according to equation (1) [8], transform the
I ( x, y ) by using 2-D wavelet.
Fig. 1. An example of the preprocessing of palm-print (a) Original Palm-print (b) the edge and corners of palm-print(c) the chopped region of palm-print (d) Region of interest (128*128 pixels) w ( a , b1 , b2 ) =
Where
1 a
+∞ +∞
∫ ∫ I ( x , y )ψ (
−∞ −∞
x − b1 y − b2 , )dxdy a a
(1)
a is scale parameter, b1 , b2 are translation parameters, ψ ( x, y ) is 2-D
wavelet transform functions.
A New Palm-Print Image Feature Extraction Method
41
As the Haar wavelet have the characteristics of orthogonal, compactness and generalized linear phase, so in this paper, we use Haar wavelet to transform the ROI image, and decompose the image in three directions. Haar wavelet can be defined as: 1 ⎧ ⎫ ⎪1, 0 ≤ x < 2 , 0 ≤ y < 1; ⎪ ⎪ ⎪ 1 ⎪ ⎪ ψ H ( x, y ) = ⎨ − 1, ≤ x < 1, − 1 < y ≤ 0; ⎬ 2 ⎪ ⎪ ⎪ 0, else ⎪ ⎪ ⎪ ⎩ ⎭
(2)
Decomposition algorithm [7] is as follows: ⎧ d k0 ( l , i ) ⎪ ⎪ 1 ⎪ d k (l, i) ⎪ ⎨ 2 ⎪ d k (l, i) ⎪ ⎪ d 3 (l , i ) ⎪⎩ k
=
∑ ∑ y
x
=
∑ ∑
=
∑ ∑
y
x
y
=
x
∑ ∑ y
x
( x, y )h ( x − 2l)h ( y − 2i) ⎫ ⎪ ⎪ d k1 + 1 ( x , y ) g ( x − 2 l ) h ( y − 2 i ) ⎪ ⎪ ⎬ d k2 + 1 ( x , y ) h ( x − 2 l ) g ( y − 2 i ) ⎪ ⎪ d k3 + 1 ( x , y ) g ( x − 2 l ) g ( y − 2 i ) ⎪ ⎭⎪ d
0 k +1
(3)
The result of wavelet transformed palm-print image is shown in figure 2.
Fig. 2. An example of three level wavelet decomposition of palm-print image
Then we construct the wavelet energy feature of the decomposed image,
H i Vi and
Di are the i level wavelet decomposition in the horizontal direction, vertical and diagonal directions of the details of the image. The i level wavelet energy in the corresponding directions of the image can be defined as [9,10]: E ih = E iv =
E
d i
=
M
N
∑ ∑ [H x =1 y =1 M
N
x =1
y =1
∑ ∑ M
( x , y )] 2
[V i ( x , y ) ] 2
(4) (5)
N
∑ ∑ x =1
i
y =1
[ D i ( x , y )]2
(6)
42
J.w. Li and M. Sun
These energy features reflect the edge intensity of the i level decomposed wavelet image in horizontal, vertical and diagonal directions. The wavelet decomposition level coefficients on each component of the vector of energy are defined as follows:
vi = ( Eih , Eiv , Eid )i ,2,",M
(7)
Where M is the number of the whole level of wavelet decomposition. Obviously, the energy vectors vi reflect global feature of the palm-print image, and can not describe the information of different regions of the palm. To solve this problem, we divide each detailed image into S × S disjoint blocks, and calculate the wavelet energy of every sub-image. Finally, we use the energy vector of every block to construct multi-resolution texture information of palm-print. Palm-print texture feature vector can be defined as v :
1 1 1 M M M v = (v (1) , v (2) " , v (3×S ×S ) ," , v (1) , v (2) ," , v (3×S ×S ) )
(8)
i v ( j ) ( j = 1,", 3 × S × S ) describes the energy of every block of three detailed images ( H i Vi Di ), which
Where M is the largest level of wavelet decomposition,
, ,
is decomposed by wavelet. Finally, we normalize
v as follows:
1 M M V = (V(1)1 ,V(2) , ", V(1)M , V(2) , ", V(3* S *S ) )
V(ij ) =
i v ( j ) M 3* S * S
∑∑ k =1
v
k (1)
(i = 1, " , M ; j = 1, " , 3* S * S )
(9) (10)
l =1
According to equation (10), we define the i level wavelet energy feature as follows: i i V i = (V(1)i , V(2) , ", V(3* S *S ) )
(11)
The i level wavelet energy feature which reflects palm-print image in the different scale, location, and different texture features in different directions is calculated by the i level wavelet coefficients. Then we get energy vector by construct every level wavelet energy feature as follows:
V = (V 1 ,V 2 , ",V M )
(12)
The wavelet feature which composed by every level of energy wavelet reflects texture feature of palm-print image at different resolutions, different regions and different directions.
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3 Principal Component Analysis As wavelet feature vector V is high dimensional, so we use principal component analysis to deal with high dimensional features. The key is to find the PCA transform axis. And let’s introduce PCA briefly. Suppose the variable x has N n×1
samples, xk ∈ R (k = 1, 2, " , N ) , We define its mean vectors as covariance matrix can be defined as follows:
C=
1 N
u , then
T
N
∑ ( xk − u )( xk − u ) ∈ R n×n
(13)
k =1
Here we define
Z = [ x1 − u, x2 − u, " , xN − u ] ∈ R n×n
(14)
Then we can get
C= We assume
1 ZZ T N
(15)
Wpca = [ w1 , w2 , " , wn ] , w1 , w2 ,", wn as the eigenvector of C ,
then we can choose the number of dimensions of transformed data we want, if we set the dimension r ,then we get r eigenvectors ( w1 , w2 ," , wr )which correspond r eigenvalues. In this paper, we reduce the dimensions of the training samples’ feature vectors V by using PCA transform, and get Wvpca
= [ wv1 , wv 2 ," , wvr ] in PCA feature space.
The training samples’ feature vectors V are mapped to feature space, eigenvalues of Wvpca can be defined as follows:
avpca = [ av1 , av 2 ," avr ] .
(16)
We use PCA to deal with every level wavelet energy features, and get reduced dimensional
1 2 M V pca i = (V pca , V pca , ", V pca ) , we call V pca i as PWEF .
4 Experiments and Results Analysis We test this feature extraction method on Polyu-Online-Plam-print Database. In the experiment ,we use 200 persons palm-print images ,and choose 9 palm images of every person randomly .To every palm ,we use 6 images as training set ,other 3 images as testing set. We use Haar wavelet to deal with these images samples, and get 5 level wavelet decomposed energy blocks ,every block is divided into 4*4 subblocks, the vector V ’s dimension is 240 ,and then use PCA to deal with every block,
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finally ,we get every level’s PWEF ,the dimension of PWEF is 40. We use the mean value of every sample’s PWEF as the corresponding person’s template. In order to investigate the performance of the proposed approach, each sample in the database is matched against the other samples. The matching between palm-prints which are captured from the same palm is defined as a genuine matching. Otherwise, the matching is defined as an impostor matching. A total of 120,000 matching have been performed, in which 600 matching are genuine matching. We do this operation 5 times by using 5 levels PWEF . Figure 3 shows the genuine and impostor matching scores distribution. The scores of the genuine match of the first ,second ,third , forth, fifth level PWEF corresponding concentrates at 15,38,26,23,20, the scores of the impostor match of the first ,second ,third , forth, fifth level PWEF corresponding concentrates at 35,50,58,60,70. These two peaks are clearly separated and the distribution curve of the genuine matching scores intersects very little with that of impostor matching scores. Therefore, the proposed approach can very effectively discriminate between palm-prints.
Fig. 3. The Five Levels
PWEF
Distributions of Genuine and Impostor Matching Scores
In the processing of recognition, we use the nearest neighbor classifier to calculate the distance between testing sample and every training sample. The result of recognition is shown in table 1.
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Table 1. Correct Recognition Rate, Training and Recognition Time
Method
PCA 2DPCA LDA ICA PCA&LDA 1 level PWEF 2 level PWEF 3 level PWEF 4 level PWEF 5 level PWEF
correct recognition rate 93.2% 92.26% 96.7% 95.75% 97.8% 98.45% 95.35% 94.57% 97.67% 99.22%
Training time
recognition time
18.4313s 17.2537s 22.7625s 15.1397s 22.7625s 13.2356s 12.9683s 13.3987s 13.4735s 13.1848s
0.1094s 0.1503s 0.1950s 0.1538s 0.2210s 0.1235s 0.1300s 0.1247s 0.1267s 0.1295s
We use the same training set to test PCA, 2DPCA, LDA, ICA, PCA & LDA and find that recognition accuracy is improved by nearly three percentage points, the time of recognition improved 0.07s averagely. From the experiment of palm-print recognition, we get the ROC in figure 4 which reflects the performance of the proposed feature extraction algorithm.
Fig. 4. The ROC Curve of the Proposed Approach
From the ROC Curve, we can see equal error rate reach about 0.60%, so the recognition accuracy are able to meet our expected accuracy. And it fully illustrated PWEF feature extraction method in palm-print recognition system’s advantage.
5 Conclusion In this paper, we applied the combination of wavelet transform and PCA on palmprint image feature extraction. Firstly, we use edge detection algorithm and corner
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detection algorithm to locate the ROI of palm-print, secondly, we transform the ROI with Haar wavelet, thirdly, we use PCA to deal with the transformed ROI image and get the PWEF. Through the recognition experiment, the correct recognition rate increased nearly 3% and recognition time reduced about 0.07s.So the proposed method can describe palm-print texture features, and has a wide application in the field of biometric technology.
References [1] Connie, T.J., Andrew, T.B.: An automated palm-print recognition system; Image and Vision computing, 501–515 (2005) [2] Lu, G., Zhang, D., Wang, K.: Palm-print recognition using eigenpalms features. Pattern Recognition Letters 24(9210), 1463–1467 (2003) [3] Li, Q., Qiu, Z., Sun, D., et al.: Online palm-print identification based on improved 2DPCA. Acta Electronica Sinica 33(10), 1886–1889 (2005) [4] Wang, J., Zhang, Z., Zhang, Y., et al.: A guantitative analysis for complicated spectra based on independent component analysis. Journal of Optoelectronics ·Laser 18(6), 741– 745 (2007) [5] Wu, X., Wang, K., Zhang, D.: A novel approach of palmline extraction. In: Proceedings of Third International Conference on Image and Graphics, pp. 230–233 (2004) [6] Tico, M., Immonen, E., Ramo, P., et al.: Fingerprint recognition using wavelet features. In: Proceedings of 2001 IEEE International Symposium on Circuits and Systems, vol. 2, pp. 21–24 (2001) [7] Mallat, S.: A Wavelet Tour of Signal Processing, 2nd edn. Academic Press, New York (1999) [8] Mallet, S., Hwan, W.: Singularity detection and processing with wavelets. IEEE Transactions on Information Theory 38(2), 617–643 (1992) [9] Wu, X., Wang, K., Zhang, D.: Wavelet Energy Feature Extraction and Matching for Palm-print Recognition. Journal of Computer Science and Technology 20(5), 411–418 (2005) [10] Wu, X., Wang, K., Zhang, D.: Wavelet based Palm-print Recognition. In: Proceedings of the International Conference on Machine Learning Cybernetics, pp. 1253–1257. IEEE, USA (2002)
A Non-linear Model of Nondestructive Estimation of Anthocyanin Content in Grapevine Leaves with Visible/Red-Infrared Hyperspectral JiangLin Qin1,2,*, Donald Rundquist2, Anatoly Gitelson2, Zongkun Tan1, and Mark Steele2 1
Guangxi Institute of Meteorological Disaster-Reducing Research; No.81, Minzu Avenue, Nanning, Guangxi, P.R. China. 530022 2 Center for Advanced Land Management Information Technologies (CALMIT), University of Nebraska-Lincoln, Lincoln, NE 68583-0973
Abstract. The anthocyanin(Anth) content in leaves provides valuable information about the physiologocal status of plant. Thus, there is a need for accurate, efficient, practical methodologies to estimate this biochemical parameter. Hyperspectral measurement is a means of quickly and nondestructively assessing leaf Anth in situ. Wet chemical methods has traditionally been used for this purpose. Recently, NIR(near-infrared)/green, red/green, anthocyanin reflectance index(ARI), and a modified anthocyanin refelctance index(MARI) was been used to estimate the anthocyanin content. In this paper, a an artificial-intelligence technique model was introduced to establish the relationship between the anthocyanin content and reflectance of 400-750nm spectum, variation of species and growth stages. The objective of this study was to test the overall performance and accuracy of this new nondestructive techniques for estimating Anth content in grapevine leaves. Although Anth in validation data set was widely variable, the new methods were capable of accurate predicting Anth content in grapevine leaves with a root mean square error below 1.65 mg/m2, which is lower than that of MARI or ARI [20]. It documents the facts that such an approach is more suitable for developing simple hand-held field instrumentation for accurate nondestructive Anth estimation and for analyzing digital airborne or satellite imagery to assist in making informed decisions vineyard management. Keywords: Grapes, Hyperspectral, SVM (Support Vector Machine), Anthocyanin.
1 Introduction / Background Very often, in grapevine leaves, significant accumulation of anthocyanin is as a result of a number of environmental stresses such as strong light, UV-B irradiation, low temperature, drought, wounding, bacterial and fungal infections, nitrogen and phosphorus deficiencies, certain herbicides and pollutants. It may serves as indicators of grapevine leaf senescence and stress in grapevine, their detection and quantitative assessment can *
Corresponding author. Tel.: +86 771 5850120; Fax: +86 771 5865594. E-mail address:
[email protected]
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 47–62, 2011. © IFIP International Federation for Information Processing 2011
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provide important information about response and adaptation of grapevine to environmental stresses. Anthocyanins have traditionally been determined through wet-chemical methods, including pigment extraction in a solvent,spectrophotometric determination of absorbance to Anth solution, and conversion from measured absorbance to Anth content[5].However, laboratory procedures are laborious, time-consuming, and destructive to leaves. Anthocyanins, Chlorophylls , carotenoids, and other pigments participate in light absorption in particular bands and can readily be assessed with absorption and reflectance spectroscopy. During past few decades, considerable progress in development of nondestructive methods for estimating physiological state of vegetation has been achieved. But much attention was given to the estimation of Chl and Car content, not much is known about Anth estimation, and lots of them are Linear/or simple nonlinear model. Decades ago, multivariable approach[1] is developed by the USDA, but one of its assumption is the relationships between reflectance and chemical concentration are near-linear. Three bands model[6,7,4] is very popular recently year, but it is very simple non-linear model, and it can not cover the variation in species and in growth stages and even in environmental stresses, only Three bands is far from enough to be used. Very recently, NIR(near-infrared)/green, red/green, anthocyanin reflectance index(ARI, based on refelctances in bands within the green and the red-edge regions[5]), and a modified anthocyanin refelctance index(MARI, based on reflectances in green,red edge, and NIR[5,6]) was been used to estimate the anthocyanin content[20]. However, this research will propose a new approach which cover advantages in lots of methods, include Three bands model and multivariable approach, and e.g, it depends on your research on your problem. It can perfectly model the relationship between Anth content and reflectance of spectra, even environmental factors.
2 Purpose of the Paper The objectives of the current study was to investigate the performance of a reflectance-based nondestructive technique to estimate Anth in grape leaves that may contain anthocyanin , chlorophylls and carotenoids, and that may contain the scattering of leaf surface. And specifically to (1) identify the optimal position of spectral bands and their width as they relate to Anth content in grape;(2) identify the position of spectral bands as they relate to chlorophyll, carotenoids content so as to remove the afects of this two pigment in estimating Anth in grape leaves;(3)select near-infrared (NIR) band so as to remove the scattering of the grape leaf internal structure and leaf surface;(4) develop a quantitative model that accurately estimates Anth content in grapevine leaves fully employ hyperspectral reflectance at selected narrow portions of the visible spectrum (400-750 nm); (5) evaluate the performance of the new techniue.
3 Material and Methods 3.1 Selected Grape Cultivars Five grape cultivars were investigated as our research: DeChaunac, Edelweiss, Lacrosse, St.Croix, Stpepin. The red cultivars included DeChaunac and Saint Croix, while the whites were Edelweiss and Lacrosse. DeChaunac, a red French-American hybrid developed by Albert Seibel and introduced into Canada in 1946, is a hybrid of
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Seibel 5163 and Seibel 793. The vine is vigorous and more disease resistant than other French hybrids, and is cold hardy to temperatures of -26° C (-15° F). Saint Croix, a red Vitis riparia cross between ES-283 and ES-193, was introduced by Elmer Swenson in 1981. Saint Croix is a vigorous vine with known resistance to black rot and is cold hardy to temperatures of -35° C (-32° F). Edelweiss, a white Vitis labrusca cross between Minnesota 78 and Ontario cultivars, was introduced by Wisconsin grape breeder Elmer Swenson in 1980. It is known as a vigorous vine resistant to foliage diseases and is cold hardy to temperatures of -34° C (-30° F). Lacrosse is a white winegrape originated by by Elmer Swenson in Osceola, Wisconsin and introduced in 1983. It is a hybrid of (Minn 78 × Seibel 1000) × Seyval, with a medium sized berry, medium cluster and is very winter hardy. It produces a high quality, fruity, non-labrusca wine and the medium vigor vine has good tolerance to 2,4-D and resistance to disease. Stpepin. 3.2 Field Sampling of Leaves 144 leaves were sampled during seven fields campaigns undertaken on: June 26,2006 to June 28,2007. Individually leaves were selected based upon the variety they were and how healthy they looked. The selected leaves were cut from the canopy, immediately sealed in a plastic bag with a small amount of water, and paced in a cooler with ice. After fields sampling was completed, the leaves were transported to the lab, and areas of homogeneous pigmentation on each were identified and delineated with a permanent marker. In order to facilitate record-keeping, high resolution digital photographs were acquired for each group of sampled leaves using an olympus C-175 4.0 megapixel camera.
Fig. 1. Leaves, as photographed by means of the digital camera, were selected to provide samples of the various cultivars. Measurement areas were delineated on the leaves themselves. These Saint Croix leaves were sampled on July 10, 2007.
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3.3 Pigment Extraction Analytical extraction of anthocyanins is problematic since the pigment in solution absorbs at 525 nm, the same band used for analytical chlorophyll extraction. To separate absorption by the two pigments, a process of pheophytinization is conducted. The process is performed by acidifying the neutral solution to convert chlorophylls to pheophytins, which while in solution, will absorb at 654 nm and 648 nm. In a neutral solution, anthocyanins are colorless. The acidification causes the red anthocyanin absorption feature to develop. This, in addition to the conversion of chlorophylls to pheophytins, facilitates analytical extraction of anthocyanin. For each leaf sample, two to three 1-cm diameter discs were cut from the marked area. Pigments contents were calculated in a two step procedure. The punches were weighed and ground in 100% methanol using a mortar and pestle. The leaf tissue was ground until the pulp turned white in color and all pigments were suspended in the solution. The resulting homogenate was centrifuged in test tubes for 6 minutes. Absorption spectra of the solution were recorded using a cary spectrophotometer. The cary spectrophotometer was configured to measure absorption of the sample at 1 nm intervals between 400 nm and 800 nm. chlorophylls a and b and carotenoid contents were calculated from the spectra using coefficients described by Lichtenthaler [15]. Once chlorophyll absorption spectra were collected, chlorophylls were converted to pheophytins by adding HCL to each sample to produce a 99.9% methanol 0.1% HCL solution. Absorption spectra of the converted solution were recorded using the cary spectrophotometer and absorption by anthocyanins was calculated using coefficients described by Lichtenthaler [15]. Laboratory analytical anthocyanin of 144 leaves yielded an adequate range of pignment concentrations, ranging from 1.34 mg/m2 to 64.74 mg/ m2 with a mean of 11.71 mg/ m2. The range of Anthocyanin in this study was similar to that observed by Gamon and Surfus[3] . 3.4 Measuring Leaf Reflectance Spectral-reflectance measurements were collected, at leaf level, for each of the five grape cultivars noted above using “leaf clip” with 2.3 mm diameter bifurcated fiber optic attached to both an ocean optics UBS2000 radiometer and to an ocean optics LS-1 tungsten halogen light source. The ocean optics UBS2000 radiometer uses a charged coupled device(CCD) to measure radiance with a spectral resolution of 1.5 nm across 2024 individual spectral channels ranging from 350nm to 1010nm in wavelength. The instrument has a 12 bit radiometric resolution; thus it records levels of reflectance ranging from 0 to 4095. The an ocean optics LS-1 light source uses a regulated power supply and a tungsten halogen filament bulb burning at 3100K to output a steady beam of light with a spectral range between 260 and 2500nm. In this study, the light source was turned on at least 15 minutes prior to scanning to allow the bulb and filament to warm and stabilize. The plastic leaf clip, used to position the ocean optics fiber against individual grape leaves, consisted of a black polyvinyl chloride(PVC) attachment and a bifurcated glass fiber optic with a diameter of 2.3 mm. This fiber optic is transmissive between 400 and 1000 nm and was positioned at a 60° angle relative to the leaf surface in
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order to minimize the spectral range of the instrument, was held against the abaxial side of the leaf to reduce extraneous reflectance from the reflect light being transmitted through the leaf. The ocean optics radiometer was calibrated prior to each data-collection session using a Labsphere spectral reference panel(North Sutton, NH) with a nominal reflectance of 99% between 250 and 2500nm. First, the reflectance panel was held tightly against the optic, and a spetral scans were taken prior to each data-collection session. The sensor was operated using the CALMIT Data Acquistion Program, which uses a single calibration scan collected at the time nearest to the acquisition of target scans to compute reflectance. To insure that a calibration scan used for reflectance calculation was accurate, at least three additional reflectance-panel scans were recorded for each dataset. The fourth calibration scan was plotted and compared to the plots of the previous three, it was used in subsequent processing. The reflectance spectrum was calculated as a ratio of leaf radiance of the calibration standard at wavelength . A total of 6 reflectance measurements were acquired within the marked homogenous area of each leaf using the ocean optics UBS2000 radiometer. Care was taken to distribute the location of the spectral scans throughout the entire marked area superimposed on the leaf in order to acquire an accurate representation of greenness. No data were taken at leaf edges where stain was present due to ink from the darker. The average of the six scans per sample was calculated in order to establish a single representative reflectance spectrum per leaf. Each spectral profile was numbered to correspond with the leaf from which it was acquired.
4 The Procedure for Developing the Quantitative Model 4.1 To Create Variable Set for the New Model 4.1.1 Confirming Sensitive Spectrum and/or Factors The relationship between the measured anthocyanin content and spectral reflectance at visible wavelengths (400-750 nm) is a complex non-linear form. The first task in developing an appropriate quantitative model to summarize that relationship is to determine which specific wavelengths in the visible spectrum have the greatest sensitivity for detecting subtle changes in anthocyanin content. The sensitivity calculation first makes use of the standard error in the regression of two datasets. In our case, the first dataset was the anthocyanin content associated with the sampled leaves corresponding to each of the five cultivars at every one of 4 growth stages. Each datacollection campaign in the field was considered as a separate growth stage (5 total field campaigns during 2006 and 2007). For the year of 2006, the first stage represents May 26, 2006,19 samples for Edelweiss and 25 samples for StCroix; the second stage represents June 1 and 9,2006, 10 samples for StCroix, Edelweiss, stpepin; the fourth stage represents September 19,2006,22 samples for stcroix. For the year of 2007, the second stage represents June 5, 2007, the third stage represents June 28,2007, every stage includes 6 samples for DeChaunac, Edelweiss, Lacrosse, StCroixper.The anthocyanin content datasets for the five cultivars were regressed against visible spectral reflectance, with the latter interpreted for our study as the wavelength region between 400 and 750 nm. The purpose of the many regression
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calculations was to select the most useful portions of the visible range for estimating Anthocyanin content. As an illustration of the procedure, consider Fig.2 where the data collected on June 28, 2007 are shown. Notice that the x-axis is the visible spectrum as defined above. The y-axis represents the standard error of the respective calculations associated with all 5 field campaigns. The solid black line represents the result for all samples combined (4 grape cultivars times 6 scans per leaf) for one growth stage. The red-line represents the series of standard errors for the DeChaunac grape cultivar, green represents Edelweiss, turquoise represents Lacrosse, and purple represents Saint Croix. The lowest points along the respective lines indicate the spectral regions or wavelengths where the greatest sensitivity occurs.
Fig. 2. The graphic illustrates the variation in the sensitivity of the various spectral regions to changes in Anth content. The solid black line represents the result for all samples combined (4 grape cultivars 6 times scans per leaf) for one growth stage. The red-line represents the series of standard errors for the DeChaunac grape cultivar, green represents Edelweiss, turquoise represents Lacrosse, and purple represents Saint Croix. The data shown here are from leaves sampled on June 28, 2007.
The next step in the procedure was to calculate the correlations (R) and coefficients of determination (R2) between anthocyanin and reflectance for those locations along the lines with the lowest standard errors. This was done merely to confirm the selection of wavelengths that will be used in the final model. The result of this latter calculation was the selection of fifteen spectral regions for use in the modeling procedure. The fifteen selections include the following (wavelengths in nm): 400.3 to 404.8;450.22 to 453.19;494.61 to 499.38;533.65 to 536.18; 550.62 to 553.14;641.13
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to 643.55;676.2 to 679.95;682.33 to 686.07;689.8 to 692.51; 696.56 to 699.93; 716.71 to 719.71;724 to 726;721.04 to 722.71;739.94 to 742.57;748 to 750. Next, the reflectances for the individual spectral ranges noted above are integrated by means of averaging these reflectance over the wavelength ranges (e.g., 400.3 to 404.8 nm, which contains band centers at 400.3;400.68;401.06; 401.43; 401.81; 402.19; 402.57; 402.95; 403.32; 403.7; 404.08; i.e., eleven individual channels). The averages became input variables to the developing model, along with two other factors: 1) grapevine cultivar (each cultivar was labeled, and that label, expressed numerically); and 2) growth stage of the vine (i.e., each stage was labeled, and that label, expressed numerically). The procedure was repeated for the other 16 dataacquisition dates. The quantitative model was developed by using the seventeen factors to estimate anthocyanin content. The sensitive channel is also variation between grape species: From the Fig. 2, we find very apparent variation in sensitivity between grape species. St.Croix is much more variable, there are many lower points on its sensitive curve, they are about at 499, 554, 625, 661, 693,750 nm. Normally situation, DeChaunac and Edelweiss is much more sensitive, and Lacrosse is lower sensitive, but it is not always right, we still need to confirm by caculating coefficient r2-value. The lower points is also different between grape species, for example, there is a lower point at 693.52 nm for St.Croix, but that similar lower point for Lacrosse is changed to point 686.75 nm, and for DeChaunac and Edelweiss, there is similar lower point may be changed to 721.71 nm and 737.96 nm. Another example, there is a lower spectral fields about in 625661 nm for St.Croix; but it is changed to spectral fields 652.88 to 686.41 nm for DeChaunac; and it is changed to 532.9 to 640.43 nm for Lacrosse; and there is not apparent similar lower spectral fields for Edelweiss. Then, by detail analysis the datum and figures of every growth stage, we also find significantly different sensitivity between grape species. But unfortunately, if we only pay attention to the rough-black line, e.g if we ignore the situation of the difference between grape species , you shouldn’t get those findings, the result will became worse. The sensitivity of spectral channels is changed and/or shifted according to growthstage. From growth stage of June 5,2007 to that of June 28,2007, the shape of all the sensitive curve is changed a lot. Taken St.Croix and DeChaunac as example, the similar lower points at about 550 and 680 nm is still retained, but the exact point is changed and corresponding sensitivity is also changed. And the shape of all curve is changed. While in June 5,2007, the St.Croix is very sensitive at point 550nm, but DeChaunac is not very sensitive at 550 nm. However, while the growth stage move to June 28, 2007, the most sensitive channel of St.Croix and DeChaunac is changed to point at 693.86 and 506 nm separately. Normally, the sensitivity of separate species is much more high than that of no considering species difference situation: Detail analysis of the datum and graphs of all growth stage shows that in the most situation and/or growth stages, the sensitive curve of separate species is usually under the curve of the rough-black one. It indicates that modeling on separate species will be much more effective, or we should use some kind of non-linear technique and taking consider of species and growth stage difference to get more effective model.
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4.1.2 Interaction of Anthocyanin, Chlorophylls, Carotenoids and Other Foliar Chemistry in Absorption and Reflectnce Absorption feature are broadened by multiple scattering and often interfere with one another. Organic compounds also absorb in similar wavebands, so that a wavelength is never uniquely related to a chemical. For instance, both of Anth, Chl and Car is absorb at about 550,680 nm, it makes the problem very intractable. From Fig.3a&3b, we can see that in some cases, while the Anth content is very lower, but Chl and/or Car maybe very high. For example, Edelweiss in June 5, 2007, Ant content is 2.36 mg/m2, but Chl and/or Car content is 454.5 and 97.6 mg/ m2 separately. However, the same grape species Edelweiss in May 26, 2006, Ant content is the similar 2.364 mg/ m2, but Chl and/or Car content is 24.49 and 11.22 mg/m2 separately. So the similar Anth content, but Chl and Car content is variable a lot, from 454.5 and 24.49 mg/m2 for Chl and from 24.49 to 11.22 mg/m2 for Car. As for sensitive channel of at 550.62 to 553.14 and 676.2 to 679.95 nm, the reflectance is 11.78 and 3.2 for Edelweiss in June 5, 2007 individually, and is 23.57 and 5.19 for Edelweiss in May 26,2006 separately, it is drastically variable from 11.78 to 23.57 for band of 550.62 to 553.14 nm and from 3.2 to 5.19 for band of 676.2 to 679.95 nm. So, in case of Anth lower content, the reflectance of spectrum maybe drastically variable, and so as for the absorption. The relationship between them is a very complex non-linear form, non-linear adjustment is necessary.
Fig. 3. The graphic illustrates that the reflectance and absorption of the Anth content affects by Chl and Car content. Both of Figures illustrates that in lower Anth content, the Chl and Car variates sharply, especially for the Anth content ≤15mg/ m2.
After researching above in detail, we confirm following sensitive spectrum as part of our modeling factors. There are totally fifteen spectral fields (see above), each spectral field takes the average value of the nearest several channels. Some of them are Chl or Car sensitive spectrum. For instance, 550.62 to 553.14,641.13 to 643.55, 689.8 to 692.51,696.56 to 699.93.So that the affection of Chl and/or Car can be compensated in the new model.
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4.1.3 Introduce of the Secondary Index We introduce Secondary Index, such as MARI to improve accuracy of the model. Here is the format of MARI MARI λNIR = [1/ρλGreen – 1/ρλRe] ×ρλNIR
(1)
Here we select λGreen as 550.62 to 553.14 nm spectrum, λRe as 696.56 to 699.93 nm spetrum; and λNIR as 721.04 to722.71,739.94 to 742.57,748 to 750 nm separately. So we get three MARI indices, label as MARI721 , MARI739 , MARI750 separately. We found that there is variation on MARI between grapevine species and growth stage. We also select 1/ρλGreen and 1/ρλRe and NIR700/Visible676.2 as the secondary index, totally six factors [6,7,4]. Table 1. r 2-value between Anthocyanin content Vs part of Indices Index r
2
MARI750 0.658
550.62 to553.14 0.2506
696.56 to699.93 0.0155
748 to750 0.5275
1/ρ550.62 to 553.14 0.61
1/ρ696.56 to 699.93 0.0693
Fig. 4. The graphic illustrates that in some case, 3 band model/or MARI can improve the Linear feature between Anth content and original data space ℜm in local fields, e.g. sub- dimension. It can makes a asymptote form of Fig.4b to be a near linear form of Fig.4a. It also makes that the scattering points in Fig.4b shrinks closed to the curve in Fig.4a. Especially in lower Anth content points. The data shown here are from leaves sampled on June 9,2006 of Stpepin.
From Fig.4a&4b which the data is taken from June 9,2006 of Stpepin, we can see that by introducing 3 band model/or MARI as index, the Linear feature between Anth content and original data space ℜm in local fields has been improved; in lower value points of Anth content, the points become much more closed to the curve, e.g. shrunk to the curve(Fig.4a), which shows that Errors will become more little. Those MARI indices will make that the learning procedure converges much faster. By introducing six secondary indices, we have got improvement on Eri (See Eq.(5)) percentage Error, e.g. Eri divides by its measured Anth content. After introducing
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secondary Indices, the average value of top ten samples of most high Eri percentage Error has been decreased, from 221.77% to 80.73% in our learning and predict-testing procedure, and the sample number of the most high Eri Error percentage (here it is 7 samples which Eri Error percentage 100% in our learning and testing procedure) has also been decreased to 3 samples. Those improvements will be very important in lower value point of Anth content. We can infer that the new model cover advantages in many methods, include MARI, ARI,3 bands model, because we can introduce as many indices as possible into the new model. And by learning procedure, the new model optimizes its accuracy and ability of its generalization or ability of prediction. We can infer that the new model cover advantages in many methods, include MARI, ARI,3 bands model, because we can introduce as many indices as possible into the new model. And by learning procedure, the new model optimizes its accuracy and ability of its generalization or ability of prediction. 4.2 SVM Approach to Establishing Non-linear Model Support Vector Machine is a kind of high-degree non-linear method [25, 10,11], it also possesses good robustness and lots of another good feature, those characteristics make it become one of the most prominent machine learning technique for high dimension sparse data. The principle of the technique is summarized below. Taking measured Anthocyanin content Yi and its corresponding factors <xi1,xi2,…..,xim>T, or we can note factor vector as Xi , it is belong to ℜm, here m = 25 represents factors number, i≤n represents sample number, as a pair dataset, normally it is called as sample. The learning task is defined a fixed array X of n points(X1, X2,…., Xn). Each data point has a desired Yi. For training, the learner receives the labels Yi for a random subset Yl , Yl ⊂ [1, 2, …, n]
⎜ Yl ⎜ = l
(2)
Of l
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and ability of its generalization or ability of prediction as likelihood as possible. Finally we had gotten best fit model, the function between Yi and <xi1, xi2,…..,xim>T Y = ω·φ(X) + b
(3)
Here ω is Weigh Vectors, b is Deviation Vector. And φ(X) is project function from ℜm space to ℜ space and can be replaced by a kernel function, here we select Gauss kernel that is expressed by k(xik, xij) = exp(-
‖x
ik –
xij
‖ / (2δ ) ) 2
2
(4)
Hereδ is the parameter of rbf kernel. 4.3 Modeling Effect from Our Training Datasets The effect of the model that we get from training dataset is shown in the Fig. 5a&5b. By the procedure of the training, we have established a kind of project from ℜm space to ℜ space. While in ℜm space, the points of original datasets of factors are existed as a curve fields, now they are shown in a linear form, and existed in a narrow channel. The strength of SVM model for the measured Anth content and predicted Anth content was very significant, its r2-value of 0.97289 (calculated according format). Fig.5b shows Error distribution of the model, Average Error is 1.3823 mg/m2, e.g. 13.32%. From the Fig.5b, we also find that the Error is not apparently increased with the increasing of Ant content. This characteristic shows that the effect of the model is better than normally statistical method. Here is the format of calculating Error, it is recorded as Eri shortly. Eri = abs(Y_predicted i – Y_original i ).
(5)
Here i=1,2,…,n. From Fig.5b, we can find that almost all Eri is under about 1.69 mg/m2 line. r2-value of 0.252 shows that the Eri is not apparently relative to the Anth content increase. This phenomenon shows that almost all useful information is transformed into SVM model, the Noise is “pure Noise”. To estimate how sensitive is each of predicted Anth content evaluated in this study, to change in reality Anth content(e.g.,Measured Anth content in Fig.5a), the Noise Equivalent Anth content(NEΔAnth) was calculated[28]. NEΔAnth = RMSE(predicted Anth vs. Anth)/[d(predicted Anth)/d(Anth)].
(6)
Here RMSE (predicted Anth vs.Anth) is root mean square error(RMSE) of the relatioanship between predicted Anth and Anth content in reality, and d(predicted Anth) /d(Anth) is the first derivative of predicted Anth with respect to Anth. Here d(predicted Anth) /d(Anth) ≈1. Fig.5b shows that Average Error is 1.3823 mg/m2. From the format (6), we also find that the Noise Equivalent is 1.65 mg/m2, it is far lower than that of ARI and MARI([20] Mark R.Steele,2009, we use the same data), it is 2.93 and 2.23 mg/m2 separately. From Fig.5b, we can find that lots of Error is under about 1.7 mg/m2 line, and lots of it near zero line. r2 of 0.252 shows that the Error is not apparently relative to the Chl content increase. This phenomenon shows that almost all useful information is transformed into SVM model, the Noise is “pure Noise”.
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Fig. 5. The graphic illustrates that the effect of the new model. Fig. 5a shows that almost all(except one) point have shrunk into two parallel line. Fig.5b shows that the Noise is not apparently increased with the increasing of Ant content. And almost all points are below under 2 mg/m2, it illustrates that Eri of lots of points is lower than 2 mg/m2.
4.4 Predict-Testing Effect of Our Model by the Testing Datasets Fig.6a&6b also show the good performance of the SVM model. The strength of prediction for Anth content of the predict-testing datasets and Measured Anth content is also very significant, its r2-value of 0.96176 (calculated according format), it is similar as that of the modeling. The Error of the predict-testing datasets in Fig.5b also shows that the nice performance of SVM. Its Average Error is 3.618 mg/m2, e.g 25.99%, the Eri is increased a little with the increase of the Anth content. We can conclude that the performance of predicting ability of the SVM is very well.
Fig. 6. The graphic illustrates the predicting performance. Fig.6a shows that all scattering points are existed between two parallel narrow lines, and its r2 of 0.96176 (calculated according format) is similar as that of the modeling in Fig.5a. In Fig.6b, its Average Error is 3.618 mg/m2, e.g 25.99%, the Eri is increased a little with the increase of the Anth content.
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4.5 Comparison with the Existing Methods To further evaluate the accuracy of the new model, we calculated noise equivalent values(NEΔAnth) for SVM and plotted against measured Anth content(Fig.6). At very lower Anth content(while Anth≤5 mg/m2), the NEΔAnth was very low, then the NEΔAnth increased sharply to 1.44 mg/m2 ,but all NEΔAnth value is still lower than 1.44mg/m2, and with the average NEΔAnth 1.0 mg/m2 . From Anth =5 mg/m2 to 10 mg/m2, the NEΔAnth value increases very little, but there is a fastly increasing from Anth =10 mg/m2 to 12 mg/m2. And then the NEΔAnth value increases slowly with Anth content. and it is lower than 3.5 mg/m2. While Anth≤15 mg/m2, the whole average NEΔAnth is 1.0 mg/m2; While Anth≥45 mg/m2, the average NEΔAnth is 3.4mg/m2, the value is a higher than that of Anth≤15mg/m2. For the whole range from 1.34 mg/m2 to 64.74 mg/ m2, NEΔAnth of SVM has average NEΔAnth = 1.65 mg/m2, which is lower than that of MARI=2.23 mg/ m2 and ARI=2.93 mg/ m2 in [20].
Fig. 7. Noise equivalent of SVM model was plotted versus Anth content throughout the range of Anth from 1.34 mg/m2 to 64.74mg/m2
The poor performance of the normally statistics methods is due to that it cannot describe the complex relationship of the Anth content and its reflectance, and the variation in species and growth stage. They cannot fully employ the wealth information of the hyperspectral. 4.6 A Simple Description about the Theoretical Principle over Procedures The learning procedure of SVM guarantees structural risk minimization of the model, and optimizes its accuracy, so SVM usually exhibit good generalization performance and high accuracy. The procedure in 4.2 item can ensure evenly distributed samples, so that the learning subset of samples can cover the ℜm space much more perfectly, and finally to ensure ability of generalization is strong.
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5 Result and Discussion Red/green[3],Modified ACI(e.g.ρλNIR/ρλ530)[27],ARI[5],MARI[5,6] are some traditional methods to estimate pigment content in leaves nondestructively. The authors of [20] used those indices to estimate Anth content in grape leaves with the same data of this study. They found that Anth prediction by Red/green was poorest with determination coefficient(r2≈0.76) and highest RMSE (7.63 mg/ m2);Anth prediction by ARI was much more accurate that the Red/green(r2≈0.96,RMSE<2.93 mg/ m2); and MARI was the most accurate in Anth prediction(r2≈0.97,RMSE<2.23 mg/ m2). In this study, we found that both of SVM and MARI/ARI has a coefficient of determination r2≈0.96 for the whole Anth ranging.The Noise equivalents of Anth estimation by both the MARI and ARI has shown in [20]. This study uses the same data, but NE of SVM has average NE = 1.65 mg/m2 ,for the whole range from 1.34 mg/m2 to 64.74 mg/ m2, which is lower than that of MARI=2.23 mg/ m2 and ARI=2.93 mg/ m2 in [20],e.g. the result has been improved a lots. For the Anth≤15 mg/m2, the NE△ Anth of MARI or ARI was about 2.23 to 2.93 mg/m2 , but NE△ Anth of SVM was 1.00mg/m2,thus SVM was much more accurate (less noisy) than both MARI and ARI, it is very sensitive for early detection of plant environmental stress. From Fig.5b&Fig.6b, we can see that that the Average Error is not apparently relative to the Anth content increase,even if Anth content is beyond 45 mg/m2,it is great interest for detection of heavily plant environmental stress.
6 Conclusion By introducing SVM, we had developed a more accurate quantitative model to like leaf Anth content in grape with spectral reflectance in visible/Red-Infrared region. The fifteen important spectral regions in visible/Red-Infrared region were identified: 400.3 to 404.8;450.22 to 453.19;494.61 to 499.38;533.65 to 536.18; 550.62 to 553.14;641.13 to 643.55;676.2 to 679.95;682.33 to 686.07;689.8 to 692.51; 696.56 to 699.93; 716.71 to 719.71;724 to 726;721.04 to 722.71;739.94 to 742.57;748 to 750. are most responsive to changes in leaf Anth content in grape. We also found that the senisitive channel is variation between grape species and growth-stages. Outperformance of the new methods is partially due to that it removed the affect of anthocyanin, carotenoids and it removed the affect by the scattering of the grape leaf internal structure and leaf surface. The new methods was found to be capable of accurately estimating Anth contents across the whole Anth range , thus the new methods is likely to allow accurate Anth determination in Vitis vinifera vines, especially can used for quantitative assessment of the early stage of plant environmental stress.
Acknowledgements We are thankful that the study is supported by the International Cooperation and Exchange Division, Guangxi Education Department, to support Jianglin qin as a visiting
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scientist working with CALMIT Faculty, and acknowledge that this study has been funded by the Ministry of Science & Technology of China (No.2008BAD08B01). The first author is grateful to Donald Rundquist, Anatoly Gitelson, Mark Steele, Christopher Harkins, and Rebecca Briles of CALMIT for providing the essential raw data, and their constructive comments and suggestions.
References [1] Curran, P.J.: Remote Sensing of Foliar Chemistry. Remote Sens. Environ. 30, 271–278 (1989) [2] Dugald, C.C., Christopher, L.B.: The Ecophoysiology of Foliar Anthocyanin. The Botanical Review 69(2), 149–161 [3] Gamon, J., Surfus, J.: Assessing leaf pigment content and activity with a reflectometer. New Phytol. 143, 105–117 (1999) [4] Dall’Olmo, G., Anatoly, A.G., Donald, C.R.: Towards a unified approach for remote estimation of chlorophyll-a in both terrestrial vegetation and turbid productive waters. Geophsical Research Letters 30(18), 1938 (2003), doi:10.1029/2003GL018065. [5] Gitelson, A.A., Merzlyak, M.N., Chivkunova, O.B.: Optical Properties and Nondestrstructive Estimeation of Anthocyanin Content in Plant Leaves. Photochemistry and Photobiology 74(1), 38–45 (2001) [6] Gitelson, A.A., Keydan, G.P., Merzlyyak, M.N.: Three-band model for nonvasive estimation of chlorophyll, carotenoids, and anthocyyanin content in higher plant leaves. Geophsical Research Letters 33, L11402 (2006), doi:10.1029/2006 GL026457 [7] Gitelson, A.A., Viña, A., Ciganda, V., Donald, C.R., Timothy, J.A.: Remote estimation of canopy chlorophyll content in crops. Geophsical Research Letters 32, L10843 (2005), doi:10.1029/2005 GL022688 [8] Grant, L.: Review article, Diffuse and Specular Characteristics of Leaf Reflectance. Remote Sensing of Environment 22, 309–322 (1987) [9] Joachims, T.: Estimating the generalization performance of a SVM efficiently (LS VIIIReport 25). Universität Dortmund, Germany (1999a) [10] Joachims, T.: Making large-scale SVM learning practical. In: Schölkopf, B., Burges, C., Smola, A. (eds.) Advances in kernel methods - Support vector learning. MIT Press, Cambridge (1999b) [11] Joachims, T.: Learning to Classify Text using Support Vector Machines Methods, Theory, and Algorithms. Dissertation. Kluwer, Dordrecht (2002) [12] Kearns, M., Ron, D.: Algorithmic stability and sanity-check bounds for leave-one-out crossvalidation. In: Proceedings of the Tenth Conference on Computational Learning Theory, pp. 152–162. ACM Press, New York (1997) [13] Kevin, S.G., Kenneth, R.M., Richard, H.S., Jessica, J.G.: Functional role of anthocyanins in the leaves of Quintinia serrata A. Cunn. Journal of Experimental Botany 51(347), 1107–1115 (2000) [14] Klinkenberg, R., Joachims, T.: Detecting Concept Drift with Support Vector Machines. In: Proceedings of the Seventeenth International Conference on Machine Learning (ICML). Morgan Kaufmann, San Francisco (2000) [15] Lichtenthaler, H.K.: Chlorophyll and carotenoids: Pigments of photosynthetic biomembranes. Meth. Enzymol. 148, 331–382 (1987)
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[16] Pirie, A., Mullins, M.G.: Changes in Anthocyanin Phenolics Content of Grapevine Leaf and Fruit Treated with Sucrose, Nitrate, and Abscisc Acid. Plant Physiol. 58, 468–472 (1976) [17] Qin, J.L.: Preliminary Inquiry on Technical Support System for the Precision-Farming with Chinese Characteristics. Transaction of the Chinese Society of Agricultral Engineering 17(3), 1–6 (2001) [18] Joachims, T.: Optimizing Search Engines Using Clickthrough Data. In: Proceedings of the ACM Conference on Knowledge Discovery and Data Mining (KDD). ACM, New York (2002) [19] Steel, M.R., Gitelson, A.A., Rundquist, D.C.: Research Note Nodestructive Estimation of Leaf Cholorophyll Content in Grapes. American Journal of Enology and Viticulture 59(3), 299–305 (2008) [20] Steele, M.R., Gitelson, A.A., Donald, C.R.: Research note nondestructive estimation of anthocyanin content in grapevine leaves. American Journal of Enology and Viticulture 60, 87–92 (2009) [21] Samuel, O.N., Gould, K.S.: Anthocyanins in leaves: light attenuators or antioxidant. Functional Plant Biology 30, 865–873 (2003) [22] Feild, T.S., Lee, D.W., Michele Holbrook, N.: Why Leaves Turn Red in Autumn. The Role of Anthocyanins in Sensescing Leaves of Red-Osier Dogwood, Plant Physiology 127, 566–574 (2001) [23] Tsochantaridis, I., Hofmann, T., Joachims, T., Altun, Y.: Support vector machine learning for interdependent and structured output spaces. In: ICML (2004) [24] Tsochantaridis, I., Joachims, T., Hofmann, T., Altun, Y.: Large margin methods for structured and interdependent output variables. JMLR 6, 1453–1484 (2005) [25] Vapnik, V.: Statistical learning theory. Wiley, Chichester (1998) [26] Wahba, G.: Support vector machines, reproducing kernel hilbert spaces, and randomized gacv. In: Schölkopf, B., Burges, C., Smola, A. (eds.) Advances in kernel methods - Support vector learning. MIT Press, Cambridge (1999) [27] van den Berg, A.K., Perkins, T.D.: Nondestructive estimation of anthocyanin content in autumn sugar maple leaves. HortScience 40, 685–686 (2005) [28] Viña, A., Gitelson, A.A.: New developments in the remote estimation of the fraction of absorbed photosynthetically active radiation in crops. Geophys. Res. Lett. 32, L17403 (2005) [29] Wantanachaturaporn, P., Manoj, K.A., Varshney, P.K.: Multisource Classification Using Support Vector Machines: An Empirical Comparison with Decision Tree and Neural Network Classifiers. Photogrammetric Engineering& Remote Sensing 74(2), 239–246 (2008) [30] Yu, C.-N.J., Joachims, T., Elber, R., Pillardy, J.: Support vector training of protein alignment models. In: Speed, T., Huang, H. (eds.) RECOMB 2007. LNCS (LNBI), vol. 4453, pp. 253–267. Springer, Heidelberg (2007)
Application of Improved BP Neural Network in Controlling the Constant-Force Grinding Feed Zhaoxia Chen, Bailin He, and Xianfeng Xu Key Laboratory of Ministry of Education for Conveyance and Equipment, East China Jiaotong University, Nanchang, P.R. China
[email protected]
Abstract. BP neural network is applied to control the amount of feed, which is the key problem during the constant-force grinding. Firstly, BP neural network is constructed. Because its convergence is slow and local minimums often occur, the adaptive learning rate is used and certain momentums are added to improve BP neural network. Then the feature parameters in time and frequency domain are picked up in grinding vibration signals. With these feature parameters BP neural network is trained. As the result it makes the amount of grinding feed recognized precisely. Comparing the practical amount of feed with the set one, the system sends commands to increase or decrease the feed .So the amount of feed regains the set one. This method realizes the autocontrol of the grinding feed, and puts forward a new method for constant-force grinding. It combines the features in time domain with those in frequency domain, and overcomes the limitation of the method which picks up feature parameters only in time domain or in frequency domain. At the same time this method provides a new clue of integrating other feature parameters in the grinding. Practice proves its good effect. Keywords: BP neural network, Feature parameter, Constant-force grinding, Feed.
1 Introduction The grinding is a method of machining with high precision. As a kind of grinding, the constant-force grinding is advanced to form curve shapes, which controls the force in the grinding and makes the wheel contact the workpiece uniformly. The premise of realizing the constant-force grinding is to recognize the feed of the wheel. Great attention has been paid by the researchers to the ways of monitoring the grinding on line [1] [2]. Generally, several feature parameters which can reflect the state pattern of grinding are the main basis for this work. Thus whether the on-line monitoring can be done depends on the effectiveness of the feature parameters. In some references the feature parameters are picked up only in time domain or in frequency domain [3] [4], and by this method the grinding feed cannot be recognized precisely inevitably. As BP neural network has the distinctive advantage in merging various feature parameters, this paper presents the application of improved BP neural network on the basis of picking up the feature parameters of the vibration signals in the grinding. The D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 63–70, 2011. © IFIP International Federation for Information Processing 2011
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aim is to recognize the grinding feed, control the amount of feed automatically and realize the constant-force grinding.
2 Principle of BP Neural Network BP neural network defines the learning process consists of the forward propagation of the signal and backward propagation of error. In the forward propagation, the input sample is transmitted from the input layer, after processed by every hidden layer in sequence, then to the output layer. If the actual output cannot match the expected one (i.e. teaching signal), the backward propagation of error begins. This propagation means passing the output error through the hidden layers to the input layer reversely in some way. At the same time, the error is allocated to all units of each layer to obtain the error signal of each layer, which is the basis of correcting every unit weight. This adjustment of the weight for each layer is cycled, which is just the training process of the network. The process ends off when the output error is diminished to what is accepted or when the learning times is up to what is set in advance. The main structure of BP neural network is that, the network is composed of nodes at different levels and the outputs from the nodes at a certain level are passed to those at next level. These outputs are amplified, attenuated or inhibited for different connection weight. Except the input layer, the input to each node is the weighted sum of the output from the former node. The stimulation output of each node is determined by the input, the activation function and the threshold. Figure 1 shows the main structure of BP neural network.
y1
ym
y2
…
v11
vmL
…
1
L wLn
w11
… x1
x2
xn
Fig. 1. The main structure of BP neural network
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The learning algorithm of BP neural network is the gradient search rule to make the mean square deviation between the actual and expected outputs of the network least. As the error is propagated backward, it is corrected simultaneously. This is the learning process of the network, which contains two steps: forward calculation and backward adjustment. The activation function is S-typed:
1 . 1 + e− x
f (x) =
(1)
The input to node l in the hidden layer is expressed by n
netl ( x) = ∑ wlj x j + θ l .
(2)
j =1
The output from node l in the hidden layer is determined according to
hl = s( netl ( x)) .
(3)
The input to node k in the output layer is expressed by L
net k (h) = ∑ vkl hl + θ k .
(4)
l =1
The output from node k in the output layer is determined according to
yk = s (netk (h)) . L
n
l =1
j =1
y k = s(∑ vkl s(∑ wlj x j + θ l ) + θ k )
(5)
.
(6)
k = 1, 2,", m For a continuous mapping F : R → R , a sample is the data representing the n
input and output, which is
m
( x1 , x 2 , " x n ; o1 , o 2 , " , o m ) and
is fit for the
relationship:
F ( x1 , x2 ," xn ) = (o1 , o2 ,", om )
.
(7)
The error of network can be calculated by following equation:
1 m 2 1 m 2 E = ∑ ( yk − ok ) = ∑ ek . 2 k =1 2 k =1 ( here, ek output.)
(8)
= yk − ok that is the difference between network output and mapping
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To make the network master this sample, the error must be as little as possible. This can be realized by adjusting the weights vkl and wlj, the simplest method of which is gradient descent algorithm. m ∂E ∂e ∂yk ∂netk = ∑ ek k ∂ν st k =1 ∂yk ∂netk ∂ν st . = es s′(net s (h ))hl = δ s hl
(9)
m ∂E ∂e ∂yk ∂netk = ∑ ek k ∂wij k =1 ∂yk ∂netk ∂wij m
= ∑ ek s′(netk (h ))ν ki s′(neti (x ))x j .
(10)
k −1 m
= ∑ δ kν ki s′(neti ( x ))x j = δ i x j k −1
(11)
m
δ i = (∑ δ k vki ) s′(neti ( x))
.
k =1
The correction value
Δvkl and Δwlj is is proportional to error function and the
relationship can be expressed
Δvkl = ηδ s ht .
(12)
Δwlj = η δ i x j .
(13)
The threshold θ is variable and also need correcting, the principle of which is the same as the correction of weights. Because local minimums often occur in BP neural network, certain momentums should be added to avoid it. Meanwhile, the adaptive learning rate must be used to speed the training [5] [6].
3 Analysis of Grinding Experiment The grinding experiment is made on the CNC external cylindrical grinding to obtain constant-force grinding. In the experiment, the acceleration sensor is fixed on the side of grinding carriage and the samples are picked up with the high-speed A/D sampler, the frequency (fs) of which is 1MHz. The workpiece is cylindrical and made from GCY15.The wheel is made from red corundum the granularity of which is 80.First, the vibration signals are recorded when the feed is 1μm 2μm 3μm respectively.
、 、
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Then the feature parameters about different feed are picked up to train the network. Finally, the trained network is used to recognize the feed, ensuring it is 2μm. 3.1 Features Pick-Up of Signals
Some work must be done to fulfill real-time monitoring. That is to analyze appropriate data, judge the current feed, and give commands the grinding tool should go ahead or back. For instance, if the current feed is calculated to be 3μm and the expected is 2μm, the wheel is controlled to retreat for 1μm. If the quantity of data analyzed each time is too big, the processing time is long and the operation is not live. If the quantity of data analyzed each time is too little, the features picked up are representative. After a lot of tests, the quantity of data analyzed each time is 500. From the 500 data analyzed each time, some features should be picked up in time and frequency domains, to study the features of signals comprehensively. In time domain, they are mean and standard deviation. In frequency domain, they are maximum value of amplitude spectrum and frequency there. A part of feature parameters are showed in Table 1, 2 and 3.Tests show any one in the four kinds of features cannot recognize the feed individually, because they are overlapped in every feed. So it is necessary to integrate the four kinds of features to recognize the feed precisely. Table 1. Feature parameters for the 1μm feed mean
standard deviation
1.423 0.383 1.170 0.570
55.269 50.913 38.368 47.805
maximum value of amplitude spectrum 16.591 16.278 10.379 13.018
frequency (KHz) 87.890 83.984 76.171 87.890
Table 2. Feature parameters for the 2μm feed mean
standard deviation
1.092 0.566 0.403 0.266
38.570 39.267 50.029 49.210
maximum value of amplitude spectrum 10.649 10.842 13.463 20.331
frequency (KHz) 58.593 72.265 91.145 82.465
Table 3. Feature parameters for the 3μm feed mean
standard deviation
0.944 0.465 0.929 1.209
60.669 36.084 58.294 41.587
maximum value of amplitude spectrum 21.766 8.764 21.263 17.381
frequency (KHz) 58.593 42.968 68.359 58.593
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3.2 Construction and Training of Improved BP Neural Network
The first thing is to determine the structure of the network. According to Kolmogov theorem [7], an N× (2N+1) ×M three-layered network is designed as recognizer, whose structure is shown in Figure 2. Here, N is the number of components of input vectors and M is the number of output categories. In this paper, N is 4 and M is 3.So in the network there are 4 input nodes, 9 hidden-layer nodes and 3 output nodes. When the output node is expressed as (1,0,0), the feed is 1μm. Similarly, (0,1,0)means 2μm and (0,0,1)means 3μm. In BP network model, the activation function of hidden layers is tansig and the one of output layers is logsig. Because in the three elements of output vectors one is 1 and the other are 0, the outputs must be processed by competitive transferring function [8] [9].
Fig. 2. The structure of the actual BP Neural network
Performance is 0.0149951, Goal is 0.015
0
Training-Blue Goal-Black
10
-1
10
-2
10
0
50
100
150
200
250 300 526 Epochs
350
400
450
500
Fig. 3. The training error curve of the network
In order to train the network more fully, 40,000 sampling data are chosen, and from every 500 sampling data the features are picked up. The adaptive learning rate is used and certain momentums are added to improve BP neural network, because the velocity of its converge is very slow, and the network falls into the situation of local extrema easily. Figure 3 shows the training error curve of the network. From Figure 3, it can be seen that the network converges is very well.
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The program is compiled in MATLAB. The main code including interpretation is as following. %Read the training data from file which is made from sampling data. p=load('tezheng.txt'); %According to the feature of network, p must be transposed. p=p'; %Construct the network net=newff(minmax(p),[9 3], {'tansig','logsig'}, 'traingdx'); %Set the starting value of network net.LW{2,1}=net.LW{2,1}*0.01; net.b{2}=net.b{2}*0.01; %Set the parameter of the network net.performFcn='sse'; net.trainParam.goal=0.015; net.trainParam.show=100; net.trainParam.epochs=5000; net.trainParam.mc=0.97; %Read the target value of the network. t=load('target.txt'); %According to the feature of network, t must be transposed. t=t'; %Training the network. [net, tr]=train(net, p, t); 3.3 Verification of the Network
To verify the recognition ability of the improved BP network, the author collects corresponding data respectively when the feed is 1μ m, 2μ m and 3μm. After picked up, the feature parameters are inputted into the network. The network can recognize the feed quickly and precisely. The verification code in MATLAB is as following. %Read the data used to test the network from file which is made from sampling data. pp=load('test.txt'); %According to the feature of network, pp must be transposed. pp=pp'; %Test the network tt=sim(net, pp)• %The output should handled by competitive transferring function, so that the outcome can be 0 or 1 tt=compet(tt);
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4 Ending The feature parameters in time and frequency domain of grinding vibration signals are fused into the improved BP neural network successfully. The feed of grinding tool can be recognized precisely. This method provides a new clue of integrating feature parameters from different domains in the grinding .Also, this method makes it possible that constant-force grinding transforms from experience-control to autocontrol. Practice proves its good effect.
References 1. Zhang, X., Kuhlenkotter, B., Knueuper, K.: An Efficient Method for Solving the Signorini Problem in the Simulation of Free-form Surfaces Produced by Belt Grinding. International Journal of Machine Tools & Manufacture, 641–648 (2005) 2. Li, H.: Determination of Frequency Calculation Range of Feature Parameters in Grinding State Monitoring. Tool Engineering, 75–78 (2006) 3. Leea, D.E., Hwanga, I., Valenteb, C.M.O.: Precision Manufacturing Process Monitoring with Acoustic Emission. International Journal of Machine Tools &Manufacture, 176–188 (2006) 4. Karpuschewski, B., Wehmeier, M., Inasaki, I.: Grinding Monitoring System Based on Power and Acoustic Emission Sensors. Annals CIRP, 235–240 (2000) 5. Ferrari, S., Stengel, R.F.: Smooth function: Approximation Using Neural Networks. IEEE Trans. on Neural Networks, 24–38 (2005) 6. Hornik, K., Stinchcombe, M., White, H.: Universal Approximation of An Unknown Mapping and Its Derivatives Using Multilayer Feedforward Networks. Neural Networks, 551–560 (1990) 7. Yang, Y., Xie, G.-S.: Handwritten Digit Recognition Based on BP Neural Network. Journal of East China Geological Institute, 383–386 (2003) 8. Tang, D., Sun, H., Wang, H.: Milling Deformation Forecast with BP Neural Network. Manufacturing Technology & Machine Tool, 48–50 (2007) 9. Wu, J., Li, Y.: Intrusion detection model based on BP neural network and feature selection. Computer Engineering and Applications, 114–118 (2008)
A Semantic Middleware of Grain Storage Internet Siquan Hu1, Haiou Wang1, Chundong She2, and Junfeng Wang3 1
School of Information Engineering, University of Science and Technology Beijing, Beijing 100083, P.R. China 2 University of Electronic Science and Technology of China 3 College of Computer Science, Sichuan University
[email protected]
Abstract. The vision of Internet of Things (IOT) promises a prosperous future for grain storage quality control by integrating all sensors deployed in the individual grain bins into a global grain storage system. However, since the data format and the data semantic of the monitoring systems are not unified, heterogeneous systems equipped with sensor networks are pending integration and have difficulty in semantic interoperation. In this paper, we design a semantic middleware to promote the data interoperability of different grain storage systems. The proposed semantic middleware uses a multi-layer architecture and provides four basic services: semantic mapping service, query service, publish service and ontology management service. Raw sensor data are converted to RDF format by semantic annotation. Semantic data are stored in the knowledge base and can be queried and reasoned. The semantic interoperation middleware will promote data interoperability, information search and retrieval, automatic inference and extendibility in the global grain storage internet. Keywords: Semantics, Middleware, Grain Storage Internet.
1 Introduction Food supply security is a worldwide challenge nowadays; many countries have built grain storage basements distributed over the world. To ensure a healthy storage condition for grains, different IT infrastructures have been built to monitor the condition of temperature and humidity [1], [2]. The vision of IOT [3], [4], [5] gives us a prosperous future that the storage quality and quantity of the grain products in the same country or transnational can be recorded and integrated into a global grain storage system based on the technology of sensor networks, internet, distributed database and cloud computing etc. However, at least currently there are many challenges to achieve such vision. One of the challenges is that these systems are designed, operated and maintained by different organization, the data format and the data semantic of the IT system are not unified and lack well-accepted standards, thus causes difficulty in interoperation and integration even in the same country. The grains in storage are products of agriculture field, which requires the monitoring of soil condition, weather, water-flow, crop etc. For that purpose different D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 71–77, 2011. © IFIP International Federation for Information Processing 2011
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sensors are needed. Either wired or wireless, these sensors connect to form a sensor network to gather the context data of the grain. Therefore, heterogeneous systems equipped with sensor networks, with vastly different capabilities such as temperature, humidity, light, gas and biology metrics measurements are pending integration. In this paper, we design a semantic middleware to promote the interoperation ability of the different grain storage system. The envisioned goal is to provide semantic interoperation middleware to the global grain storage network that will promote data interoperability, information search and retrieval, automatic inference, and extendibility.
2 Related Work In agriculture domain, sensor network based solutions have been used for several years for monitoring or controlling purposes. W. Zhang et al. at Carnegie Mellon University developed a small wireless sensor network to monitor plant nursery [6]. Sensors were used to collect soil and air humidity, moister, temperature and light information. Yunseop Kim et al. [7] developed an electronically controlled sensor based irrigation system that provides the facility to monitor soil moister and temperature, weather information and sprinkler position remotely using the Bluetooth and GPS technologies. Tim Wark et al. created a pervasive, self configurable sensor based solution [8] to analyze the behavior of animals and their control as well as the pastures assessment. However, all these projects are close loop applications which have weak interoperation ability. To handle interoperation problem, Semantic Sensor Web [9] are proposed to integrate the Semantic Web with sensors networks [10], [11], which will bring benefits such as a more expressive graph based representation that models relationships as first class objects, the use of Uniform Resource Identifiers that allows all concepts to be independently accessible throughout the Web, and a triple-pattern encoding scheme that provides for simplified integration of heterogeneous datasets. Based on such mechanisms, the semantic middleware is proposed for different applications, such as E-Discovery, E-Government, Mobile computing [12], [13], [14].
3 Design of the Middleware The semantic middleware exploits ontology to support the semantic integration and functional collaborations between different information systems. Rather than assuming a specific technical architecture or environment such as Service Oriented Architecture (SOA), web services, the semantic middleware only assumes that collaborations are realized through the exchange of messages. This provides the flexibility of implementation when SOA or web services are not supported in many legend systems. To maximize the reusability, a service-based architecture is exploited in our middleware design showed in Fig. 1. From the aspects of the users, four services are provided: Publish Service, Query Service, Semantic Mapping Service, and Ontology Management Service.
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Both Publish service and Query Service interact with the data store through a unified Query Controller. Publish service will deliver the data set results to the web client under the default query configuration. The Query service allows users set flexible query conditions and makes various semantics related queries Semantic data exchange and query need a interface or no one knows how to connect to the semantic data store. The solutions are quite dependable, the popular solution is using reasoning server, but any kind of data exchange mechanisms is workable. In our design, the Query Controller is based on a reasoning server.
Fig. 1. The service architecture of the middleware
The Semantic Mapping service helps to make semantic annotation to raw sensor data. This service includes a optional syntax processing layer and a required layers are semantic annotation layer. The syntax processing layer transfers the raw sensor data into XML files or streams if the input is not in XML-format. The Semantic annotation layer abstracts the processed outputs from the heterogeneous, low-level data sources such as sensors. Context information is added here through application specific ontology which can be plugged and automatically initiated without any further human intervention. The Semantic Mapping service analyzes the incoming XML message and store it into the ontology model in the form of ontology class individuals. After semantic annotation, the data is stored into data stores as triple statements which form the underlying graph of the model. Both the syntax mapping rules and semantic mapping rules can be stored in the instance KB (knowledge base) and managed by the Ontology Management service. The Ontology Management service handles the ontology definitions and semantic rules. The ontology definition can be an owl file in the instance knowledge base, or mapping rules from XML to RDF stored in the KB. These mappings should include
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both the raw sensor data and the context of the data generation. The meta data of the sensor output are the necessary description about the raw data itself. Take raw data produced by a temperature sensor for example. We have to make it clear that the raw data is a temperature measurement, how accuracy it is, and in what conditions it is valid, which usually depends on the capability of sensing devices. Different sensing devices may have different kinds of meta data. The context information is about the context information in which the raw data was generated, for example, the location of sensor node, the ID of sensor node and the timestamp of data captured. The semantic rule is used to trigger the modification of ontology when some condition is met. For example, when the humidity is too high then fire an alert.
4 The Prototype Implementation To evaluate the proposed design, we have implemented a prototype of the semantic middleware for the grain storage internet. The semantic framework is based on the Jena [15] which is a Java framework for building Semantic Web applications. It provides a programmatic environment for RDF, RDFS and OWL, SPARQL and includes a rule-based inference engine. The backend database is PostgreSQL [16]. The reasoning server is the open source Pellet [17] which provides standard reasoning services for OWL ontologies. It supports both the essential OWL DL reasoning and OWL 2 EL reasoning. The query controller use Pellet to represent and reason about information using OWL. An ontology improved on OntoSensor [18] is used in the prototype as an experimental ontology. OntoSensor references and extends the IEEE Suggested Upper Merged Ontology, which defines general concepts and associations. In our implementation, the semantic mapping service will transfer the raw XML reading into RDF/OWL statements. For example, from a sensor node 1 equipped with a sensor board MTS310 (bordid=130), we get a xml packet in following format. <MotePacket> <ParsedDataElement>
amtype0 <ParsedDataElement>
nodeid1 <ParsedDataElement>
group11 8 <ParsedDataElement>
board_id130 <ParsedDataElement>
packet_id1 <ParsedDataElement>voltage 3.25 <ParsedDataElement>temp25. 4 <ParsedDataElement>light74 9
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After mapping, the data is stored into the ontology models as following format, which is the output after semantic annotation. 3.2525.4 25.4 749 From the output we can see the all sensor readings have been endowed formal semantics which provides the basis of semantic interoperability. To verify the integration effectiveness of different grain storages using the semantic middleware prototype, two senor networks are deployed as Fig. 2. Each sensor network has 100 sensor nodes distributed in 2 grain storage bins. Each network has a gateway running the proposed middleware.
Fig. 2. The sensor network deployment structure
Every 30 seconds, the server in Net 1 sends a query to retrieve the readings of a random one of the node 101- 200 which is in the Net 2, vice versa. The observed query results show the data can be access successfully cross the bounds of the subnets, thus the integration is seamless.
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5 Conclusion and Future Work The semantic integration of the global food storage system is an exciting vision that maximizes the utilization of the potential of data resources on existed food monitoring information systems. The semantic interoperability is a necessary prerequisite for automatic search, retrieval and processing of grain storage sensor data. This paper is a step further towards to unify the domain objects, sensor readings, time/space semantics, lifecycles of grains. The benefits of our work are to automatic the syntax and semantic annotation of sensor data and provide the semantic unification – a solid base for integration of heterogonous grain storage systems to form a global Internet of things on grain storage. As for future work, we are planning to perform more comprehensive performance analysis by integrating more sensor network of grain storage in China and considering more real life scenarios and extending the system to the storage information system of other kinds of food. This effort will be a further step in the direction towards enabling semantic web to access and process the global food storage system. Our paper demonstrates how semantic middleware can be applied to grain storage internet of things. There are at least two advantages of our approach towards building such a future internet. First, RDF as the common information representation enables the semi-structured data sources conveniently handled and additional sources added incrementally without need to modify a global schema. Second, a richer domain model can be provided by formal ontology definition with supporting inheritance hierarchies for classes and properties.
Acknowledgement Project supported by the National High Technology Research and Development Program of China (2008AA01Z208 and 2009AA01Z405), the National Natural Science Foundation of China (60772150), and the Youth Foundation of Sichuan Province (2009-28-419) and the Applied Basic Research Program of Sichuan Province ( 2010JY0013).
References 1. Armstrong, P.: Wireless Data Transmission of Networked Sensors in Grain Storage. In: ASAE Annual International Meeting, Las Vegas, USA, p. 036157 (2003) 2. Rehman, A., Shaikh, Z.A.: Towards Design of Context-Aware Sensor Grid Framework for Agriculture. World Academy of Science, Engineering and Technology 38, 244–247 (2008) 3. Katasonov, A., Kaykova, O., Khriyenko, O., Nikitin, S., Terziyan, V.: Smart Semantic Middleware For The Internet Of Things. In: 5th International Conference on Informatics in Control Automation and Robotics, pp. 169–178. INSTICC, Madeira, Portugal (2008) 4. Yan, L., Zhang, Y., Yang, L.T.: The Internet of Things: From RFID to the NextGeneration Pervasive Networked Systems. Auerbach Publications, FL (2008) 5. Brock, D., Schuster, E.: On the Semantic Web of Things. In: Semantic Days 2006, Stavanger, Norway (2006)
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6. Zhang, W., Kantor, G., Singh, S.: Integrated Wireless Sensor/Actuator Networks in an Agricultural Application. In: SenSys 2004, p. 317. ACM Press, New York (2004) 7. Kim, Y., Evans, R.G., Iversen, W.: Remote Sensing and Control of Irrigation System using a Distributed Wireless Sensor Network. IEEE Trans. Instrumentation and Measurement 57(7), 1379–1387 (2008) 8. Wark, T., Corke, P., Sikka, P., Klingbeil, L., Guo, Y., Crossman, C., Valencia, P., Swain, D.: Transforming Agriculture through Pervasive Wireless Sensor Networks. IEEE Pervasive Computing 6(2), 50–57 (2007) 9. Sheth, A., Henson, C., Sahoo, S.: Semantic Sensor Web. IEEE Internet Computing 12(4), 78–83 (2008) 10. Thirunarayan, K., Pschorr, J.K.: Semantic Information and Sensor Networks. In: 24th Annual ACM Symposium on Applied Computing, pp. 1273–1274. ACM Press, New York (2009) 11. Brunner, J.S., Goudou, J.F., Gatellier, P., Beck, J., Laporte, C.E.: SEMbySEM: a Framework for Sensors Management. In: 1st International Workshop on the Semantic Sensor Web, Herkalion, Greece, pp. 19–34 (2009) 12. Butler, M., Reynolds, D., Dickinson, I., McBride, B., Grosvenor, D., Seaborne, A.: Semantic Middleware for E-Discovery. In: IEEE International Conference on Semantic Computing, pp. 275–280. IEEE Press, New York (2009) 13. Sanchezl, A., Ojo, A., Janowski, T., Estevez, E.: Semantic Interoperability Middleware – Cases and Applications in Electronic Government. In: 3rd International Conference on Digital Information Management, pp. 800–805. IEEE Press, New York (2008) 14. Corradi, A., Montanari, R., Toninelli, A.: Adaptive Semantic Middleware for Mobile Environments. Journal of networks 2(1), 36–47 (2007) 15. Jena, http://jena.sourceforge.net 16. PostgreSQL, http://www.postgresql.org 17. Pellet, http://clarkparsia.com/pellet/ 18. Russomanno, D.J., Kothari, C., Thomas, O.: Building a Sensor Ontology: A Practical Approach Leveraging ISO and OGC Models. In: The 2005 International Conference on Artificial Intelligence, Las Vegas, USA, pp. 637–643 (2005)
AE Feature Analysis on Welding Crack Defects of HG70 Steel Used by Truck Crane Yantao Dou1, Xiaoli Xu2, Wei Wang3,*, and Siqin Pang1 2
1 Beijing Institute of Technology, Beijing, P.R. China Beijing Information Science and Technology University, Beijing, P.R. China 3 College of Engineering, China Agricultural University, Beijing, P.R. China [email protected]
Abstract. In present paper, using Acoustic Emission (AE) as a ultrasonic technique, Welding crack has been investigated on the HG70 steel used by truck crane during three-point bending test was carried out. The study shows that the activity of AE increases greatly during the welding crack initiates and propagates, and the distributing range of AE characteristic parameters can be fixed. AE signals of welding crack initiation and expansion are typical sudden signals which have a different spectrum energy distribution range with that of unstable crack propagation. Keywords: HG70 steel, Welding crack, Acoustic Emission.
1 Introduction As an important loading and transporting machine, truck crane is widely used in various fields of national economy. To achieve high efficiency and large scale production, truck cranes are often overloaded, which result in accidents frequently. The main cause lies in the damage of structural parts, for example, boom fracture brought about by fatigue crack or weld defects. The current popular detecting technologies include macroscopic artificial inspection, ultrasonic testing, magnetic particle testing, radiographic testing, penetrant testing, stress-strain testing and so on, which often fail to have a complete and real-time detection of crane metal structures since they are often used as periodic testing or testing afterwards[4]. Acoustic Emission (AE) technology can just make up the deficiency of conventional detection methods. During the past 20 years, some research works have been carried out to the aerial personnel devices or crane structure[1-3]. The aim of this paper is to investigate the AE signals during three-point bending test of welding specimens made of HG70 steel. The typical characteristic parameters and waveform features of the AE signals are collected and extracted at the three development stages of welding crack, namely as crack initiation, growth and fracture[5], and the crack position was located by way of linear location. *
Corresponding author.
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2 Preparation 2.1 Specimen Preparation HG70 steel, commonly used in crane booms and legs, is chosen as the experimental material. Table 1 and Table 2 indicate its chemical composition and mechanics properties[6]. Table 1. Chemical composition of HG70
C 0.06
Si 0.29
Chemical Composition (weight fraction %) Mn P S Mo Cr 1.56 0.014 0.008 0.33 0.61
Nb 0.04
V 0.04
Table 2. Mechanics properties of HG70
σ s / MPa
σ b / MPa
σ 5 (%)
AKV / J
570
725
26
69
The structure of welding specimens is shown in Fig 1. The welding interface is located in the middle of the specimens. The specimens are loaded through three-point bending mode.
Welding area
Fig. 1. Structure of welding specimens
2.2 Test Equipment and the Placement of Sensors Computer controlled electro-hydraulic servo universal test machine of WDW4200 Series is adopted for the loading test, with its max. test force being 200kN, and the indicating accuracy: ±0.5%. Besides, AMSY-5 AE-System by Vallen and VSl50-M sensors are chosen for the test. The sensor’s main monitoring frequency ranges from 100 to 450kHz, and the acquired AE signals are amplified by a 34 dB fixed gain preamplifier (AEP4). The background noise under operation is found to be always below 35dB, which indicates that we can choose the voltage threshold as 40dB. With the test objects being small metal specimens, system timing parameters are specified as PDT: 300μs, HDT: 600μs and HLT: 1000μs. As shown in Fig 2, sensor 1 and sensor 2,
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placed on the same side of the specimens, provide linear location, which can obtain the AE characteristic parameters, waveform datas and AE locating features of the crack source during the loading time. 2.3 Loading Course and Process The loading test is shown in Fig 3. To eliminate the noise caused by the friction between the specimen and the support roller, a rubber pad is placed between them. At the beginning of the loading, the specimen is preloaded and unloaded three times to achieve a close contact between the specimen, rubber pad and the support roller. During the whole course, the specimens are always at the stage of elastic deformation. The speed of loading and unloading of the test machine is 1mm/min. The final testing aim is to bend the specimens at α ≤ 1300 when a macro crack can be seen by the eye. The AE signals during the whole course are collected and analyzed. F
S1
60 160
S2
Fig. 2. Placement of sensors
Fig. 3. The loading test
3 Analysis of AE Signals 3.1 Analysis of Hits and Counts versus Time As shown in Fig 4, a few AE hits are collected at the first preloading stage with rather low counts rates. When first preloaded (0 200s), the specimen undergoes elastic deformation (disturbance below 1mm) with little release of strain energy and the deformation within the material will vanish after unloading, so only a few AE signals are
~
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(a) Hits versus time
(b) Counts versus time Fig. 4. Hits and counts versus time
created which include those created by the deformation of the rubber pad and the friction as well as the agreement between the specimen and the support roller. At the 2nd and 3rd stage of loading, holding load and unloading (400 1100s), no obvious AE signals can be seen. This is partly due to Kaiser Effect, but on the other hand, it signifies there is an agreement between the specimen, rubber pad and support roller where no friction noise is produced. At the last loading (after 1100s), AE hits rates and counts rates increase rapidly, which is caused by the stress concentration in the defect area resulting from the increase of load. In part of the specimens, yield deformation occurs and tiny crack appears and propagates. With the gradual release of internal energy, a large number of AE signals are created.
~
3.2 Analysis of AE Characteristic Parameters versus Time Fig 5 shows the variation of AE characteristic parameters in the loading. At the elastic deformation stage, the value of AE characteristic parameters is rather low, with the amplitude below 60dB, energy below 103eu and the counts below 100. When the loading comes to the stage of plastic deformation and crack initiation and propagation,
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(a) Amplitude versus time
(b) Energy versus time
(c) Counts versus time Fig. 5. AE characteristic parameters versus time
AE hits gradually increase with fairly high amplitude, energy and counts. A number of high-amplitude and high-energy hits even occur simultaneously in some short-time periods, which is caused by the propagation of welding crack.
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4 Analysis of AE Signal Features at the Welding Crack Initiation and Propagation Stage 4.1 Analysis of Cumulative Hits and Counts Fig 6 exhibits its loading-time curve during the test, whereas Fig 7 & 8 respectively show the cumulative hits and counts of AE signals. A comparative study of the three Figs shows the findings: the curve indicates that the specimen enters the stage of part plastic deformation at around 1130s(I). A tiny crack occurs in the welding area and grows gradually due to the stress concentration, which dwindles the load-carrying cross section. When the loading comes to 1570s (II), the crack expands with a snap and the carry capacity falls instantly. The welding crack expands again at 1865s (III). Fig 7&8 show the two instant increases in the value which coincide with the time of the instant fracture of the metal. The findings prove that AE technology can accurately monitor the expansion of welding crack. 䋳㥋üᯊ䯈᳆㒓
Load(kN)
6
I
II
III
4.2
2.4
0
0
218
654
1090
t˄s˅ 2180
1526
Fig. 6. Loading-time Curve
I
Fig. 7. Cumulative hits versus time
II
III
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I
II
III
Fig. 8. Cumulative counts versus time
4.2 Analysis of AE Signal Location Since the initiation and propagation of welding crack is accompanied by rather active AE signals with high amplitude, the amplitude can be amplified to 45dB to filter waves and observe location events. As shown in Fig 9, location events take place mostly in the range of 25~35mm. AE signal location deviation being considered, this range accords with the welding crack location by and large, which sufficiently testify to the location accuracy of AE technology in monitoring welding crack. Fig 10 indicates that location events mainly take place at the time of crack initiation and propagation, which further proves the close relation between middle location events and welding crack.
Fig. 9. AE location
Fig. 10. Loc. Events―Time―X-Loc.
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Space filtering ( 25mm ≤ x ≤ 35mm ) and time filtering (t ≥ 1130s) are adopted to extract the typical AE signals of welding crack initiation and expansion. The distribution and range of characteristic parameters are respectively shown in Table 3. Table 3. Range of the AE characteristics of welding crack Characteristics Range Major Range
Amplitude (dB)
~100 45~70, 97~100 45
(eu)
Counts
~ 1~200
Energy
~10
1 2800
35
8
~80000
40
Duration-Time ( μs )
~2040
10
~1200
100
4.3 Analysis of Time Domain Waveform and Frequency Spectrum Features at the Stage of Tip Crack and Crack Propagation The welding crack develops through three stages: initiation of tiny crack, crack stable propagation and rapid fracture[5]. Fig 11 exhibit the waveform of AE signals at the first and second stage. The time domain waveform Fig shows that the AE signals are typical sudden ones. The frequency spectrum energy of the signals ranges from 80kHz to 380kHz with three major frequency bands: the 1st band centers on 100kHz, the 2nd from 150kHz to 200kHz and the 3rd on 300kHz. The 1st and 3rd band see rather high energy and obvious peak value.
(a) Waveform
(b) Frequency spectrum Fig. 11. Waveform and frequency spectrum of initiation of tiny crack
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At the moment of rapid fracture, a few signals of full amplitude (almost 100dB) and high energy (107 108eu) are created as shown in Fig 12. The time domain waveform shows that they are continuous signals formed by several sudden signals which are created by several crack sources. These crack sources are caused by the rapid propagation of the welding crack. As shown in the frequency spectrum Fig 12(b), the frequencies are of rich components and well-distributed between 85kHz and 330kHz. The peak frequencies occur at 100kHz and 200kHz. No obvious peak is shown in high frequency band.
~
(a) Waveform
(b) Frequency spectrum Fig. 12. Waveform and frequency spectrum of rapid fracture
5 Conclusion Acoustic emission during three-bending tests of welding specimens of HG70 steel were investigated and it was found that AE hits and counts can coincide with the
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bending and cracking of the specimens. Based on AE hits and counts as well as the loading-time curve of the specimens, welding crack can be dynamically monitored and evaluated. By way of linear location, the welding crack in the specimens can be accurately located, and the distribution ranges of various AE characteristic parameters at the stage of crack initiation and propagation are tentatively fixed. The AE signals at the stage of crack initiation and propagation are typical sudden signals whose frequency spectrum energy distributes between 80kHz and 380kHz. Obvious peak value is found at 100kHz and 300kHz. The AE signals at the stage of crack rapid propagation are continuous signals formed by several sudden signals with rich frequency components, but no obvious peak is shown in high frequency band.
Acknowledgments This study was funded by National High Technology Research and Development Program of China (2008AA042801, 2008AA042803).
References [1] Wu, Z., Shen, G., Wang, S.: Characteristics of Acoustic Emission Testing During the Propagating of External Crack on the Crane Box Beam. Nondestructive Testing 30(9), 635–639 (2008) [2] ASTM F9 14-03: Standard Test Method for Acoustic Emission for Insulated and Non Insulated Aerial Personnel Devices Without Supplemental Load Handling Attachments 9(10) (2003) [3] Drummond, G.R., Fraser, K.F., Little, J., et al.: Assessing the structure integrity of crane booms using acoustic emission. In: EWGAE: 25th European Conference on Acoustic Emission Testing Prague, Czech Republic (2002) [4] Wu, Z., Shen, G., Wang, S.: Application status of acoustic emission technology to crane’s nondestructive test. Hoisting and conveying machinary 10, 1–4 (2007) [5] Ennaceur, C., Laksimi, A., Herve, C., Cherfaoui, M.: Monitoring crack growth in pressure vessel steels by the acoustice mission technique and the method of potential difference. International Journal of Pressure Vessels and Piping 83, 197–204 (2006) [6] Sheng, G., Gao, C.: Weldability of HG70 steel Transactions of the china welding institution 25(3), 117–119 (2004) [7] Akbari, M., Ahmadi, M.: The application of acoustic emission technique to plastic deformation of low carbon steel International Congress on Ultrasonics, Universidad de Santiago de Chile (1), 795–801 (2009) [8] Xu, C., Liu, L., Chen, G.: Characteristics analysis of acoustic emission signals from steel specimens under tensile fracture and fatigue crack condition. Journal of China University of Petroleum 33(5), 95–99 (2009) [9] Carpenter, S.H., Gorman, M.R.: A Waveform Investigation of Acoustic Emission Generated during the Deformation and Cracking of 7075 Aluminum. In: Progress in Acoustic Emission VII, The Japanese Society for NDI, Japan, pp. 105–112 (1994)
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[10] Qin, G.-d., Liu, Z.-m., Wang, W.-j.: Study on Acoustic Emission Characteristics of 16Mn Steel in Fatigue Test. China Safety Science Journal 15(8), 105–109 (2005) [11] Zhou, J., Mao, H.-l., Huang, Z.-f.: Acoustic emission technique for the detecting of metal fatigue fracture. China Measurement Technology 33(3), 7–9 (2007) [12] Roberts, T.M., Talebzadeh, M.: Fatigue life prediction based on crack propagation and acoustic emission count rates. Journal of Constructional Steel Research 59(9), 681–693 (2003)
An Equilateral Triangle Waveguide Beam Splitter Zhimin Liu1,2,*, Fengqi Zhou1, Hongjian Li2, Bin Tang3, Zhengfang Liu1, Qingping Wu1, Aixi Chen1, and Kelin Huang1 1
School of Basic Sciences, East China Jiaotong University, Nanchang, Jiangxi, 330013, China 2 College of Physics Science and Technology, Central South University, Changsha, Hunan, 410083, China 3 Jiangsu Polytechnic University, Changzhuo, Jiangsu, 213164, China [email protected]
Abstract. In this paper an optical beam splitter based on an equilateral triangle waveguide (ETW) is studied theoretically and numerically. We show that an optical beam splitter bases on ETW formed only when the length of the waveguide and the location of incident light are appropriate. When the length of the ETW is one third of the self-imaging length, the incident light is divided into three identical and symmetrical beams; while the length of the ETW is one nine of the self-imaging length, the incident light is divided into twenty- seven identical and symmetrical beams, if the number is less than twenty-seven, that is because some of images overlap with each other. It is expected that the results obtained here will help to design a new splitter. Keywords: Self-imaging, Equilateral triangle waveguide, beam splitter.
1 Introduction The propagation of light along a waveguide is one of the fundamental and important questions of wave optics. In recent years the splitter and self-imaging of waveguide have been actively discussed. A theoretical and experimental investigation of the selfimaging properties of planar waveguide have been studied [1-3]. Self-images in a rectangular waveguide has been reported [4]. Similar studies [5-6] were performed on square fiber, and it mentioned that round fiber do not have the image transmission characteristics above, that is mainly because of the angular ambiguity and high symmetry. And optical power splitter(OPS) base on multimode interference waveguide has been studied [7-9]. OPS made of photonic crystal waveguide has been studied [10-11]. A few investigators have been discussed the equilateral triangle resonators [12-16] and ray optics model for triangular hollow waveguides [17], but few attentions are paid to investigate the properties of self-images in an ETW. So study on the behavior of light propagation through this waveguide would be of practical interest. In *
This work was funded by the National Natural Science Foundation of China (Grant No. 60708014), the Key Natural Science Foundation of Hunan Province (Grant No. 06JJ2034), the Natural Science Foundation of Jiangxi (2008GQW0017) and the Research Foundation of East China Jiaotong University (08JC04,09JC01).
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our previous paper [18], we showed that an image transmission through an ETW, in this paper, we study on the behavior of Gaussian beam propagation(GBP) through this waveguide. An optical beam splitter bases on ETW formed by the new study, the results may have convenience in beam splitter application.
2 Theory As shown in our previous paper [18], consider an ETW with side size a and length L (see Fig.1), and the cladding is a perfect reflector, the field vanish at the boundaries. The field inside the waveguide can be expressed by eigenfunction expansion of Helmholtz equation in the triangular section [19].
Fig. 1. Schematic diagram of an equilateral triangle waveguide ⎛ ∞ 4n 2 λ 2 ⎞⎟ E ( x, y, z ) = ∑ a((20n) , n)ψ ((20n) , n ) ( x, y ) exp⎜ − ikz 1 − ( ) ⎜ 3 a ⎟ n =1 ⎠ ⎝ ⎛ ∞ ∞ 4(m 2 + n 2 − mn) λ 2 ⎞⎟ + ∑ ∑ [a((m+ ), n )ψ ((m+ ),n ) ( x, y ) + a((m− ), n )ψ ((m− ),n ) ( x, y )] exp⎜ − ikz 1 − ( ) ⎜ a ⎟ 9 m 2 n n =1 ⎠ ⎝
(1) For integral values of m, n , with the restriction that m > 2n . For the case of m > 2n , there are two degenerate states with different symmetry properties, which can be written as follows [20] (the correct normalizations are included here): ψ ((m− ), n) ( x, y ) =
⎡ ⎛ 2π ( 2m − n) x ⎞ ⎛ 2πny ⎞ ⎛ 2π (2n − m) x ⎞ ⎛ 2πmy ⎞ ⎟⎟ ⎟⎟ − sin ⎜ ⎟ sin ⎜⎜ ⎟ sin ⎜⎜ ⎢sin ⎜ 3a 3a 3 3a ⎣⎢ ⎝ ⎠ ⎝ 3a ⎠ ⎝ ⎠ ⎝ 3a ⎠ 16
2
⎛ 2π (m + n)x ⎞ ⎛ 2π (m − n) y ⎞⎤ ⎟⎟⎥ - sin ⎜ ⎟ sin ⎜⎜ 3a 3a ⎠ ⎝ ⎝ ⎠⎥⎦
(2) ψ ((m+ ), n ) ( x, y ) =
16 ⎡ ⎛ 2π ( 2m − n) x ⎞ ⎛ 2πny ⎞ ⎛ 2π ( 2n − m) x ⎞ ⎛ 2πmy ⎞ ⎛ 2π (m + n)x ⎞ ⎛ 2π ( m − n) y ⎞ ⎟⎟ − cos⎜ ⎟⎟ + cos⎜ ⎟⎟ ⎟ sin ⎜⎜ ⎟ sin ⎜⎜ ⎟ sin ⎜⎜ ⎢cos⎜ 3a 3a 3a 3 3a 2 ⎢⎣ ⎝ 3a ⎠ ⎝ 3a ⎠ ⎝ ⎠ ⎝ 3a ⎠ ⎝ ⎠ ⎝ ⎠
(3)
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=
In the special case of m 2n there is a single nondegenerate state for each n , and the wavefunction is given by ψ ((20n) , n) ( x, y) =
⎡ ⎛ 4πny ⎞⎤ ⎛ 2πnx ⎞ ⎛ 2πny ⎞ ⎟⎟− sin ⎜⎜ ⎟⎟⎥ ⎟ sin ⎜⎜ ⎢ 2 cos⎜ a 3 3a ⎣⎢ ⎝ ⎠ ⎝ 3a ⎠ ⎝ 3a ⎠⎦⎥ 8
2
(4)
The coefficients a ((20n) , n) , a ((m+ ), n ) , a ((m− ), n) are determined by the projection of the initial
distribution onto the waveguide a((20n) , n ) ( x, y ) = ∫∫ dx1dy1ψ ((20n) , n ) ( x1 , y1 ) E1 ( x1 , y1 )
(5a)
a((m+ ), n ) ( x, y ) = ∫∫ dx1dy1ψ ((m+ ), n) ( x1 , y1 ) E1 ( x1 , y1 )
(5b)
a((m−), n ) ( x, y ) = ∫∫ dx1dy1ψ ((m− ), n ) ( x1 , y1 ) E1 ( x1 , y1 )
(5c)
In this paper, the initial light we consider a GBP E1 ( x1, y1 ) = exp[ −
x 2 + ( y − 3a 6)
ω02
(6)
]
(
Where ω 0 is beam waist size of the GBP, The GBP is launched at 0, 3a 6) , instead
(
of the center 0, 3a 3) , in order to avoid any overlap of the images. The coefficients can’t be get analytic solution, which are given by oscillatory numerical integral. L0 = 9a 2 2λ is the self-imaging length of the ETW, the detailed derivation as shown in[18], that is, at this distance (the self-imaging distance) the initial distribution repeats.
3 Numerical Results and Analysis The output field at the back face of the waveguide was numerically calculated according to Eq.(1) with the waveguide size a = 0.2mm ,the wavelength λ = 633nm and GBP with ω 0 = 10μm . Modes m, n should be taken on values for all the possible guided-wave modes, in other words, m max , n max are determined by 1−
4n 2 λ 2 4(m 2 + n 2 − mn) λ 2 ( ) ≥ 0 and 1 − ( ) ≥0 3 a 9 a
But normally, the coefficients decrease rapidly with increasing m, n , the actual number of modes which have to taken into account is much less than m max , n max [1], in this paper m, n = 100 are used in calculation. 3.1 The Field at the Face of z = 0
Firstly, at the incident face of the waveguide z = 0 , that is the incident wave. It is clear that the output field consists very well with the input field both in field intensity
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and position from Fig(2). From these we consider that the simulation procedure is correct and feasible.
Fig. 2. The field at the distance z = 0 (right is contour plot)
Fig. 3. The field at the distance z = L0
3.2 The Output Field at the Back Face of Self-imaging Length in ETW
From the theory educing we know L0 = 9a 2 2λ is the self-imaging length of the ETW, which means at this distance the initial distribution repeats. Fig(3) demonstrates the result, the field intensity and position of output field consist with the input field. Similar distributions are also observed at the distance z = nL0 ,where n is an integer. 3.3 The Output Field at the Back Face of Other Length
As shown in our previous paper [18], similar the results at the distance z = L0 3 are also simulated, obviously the initial distribution is splitted into three identical and symmetrical distributions at the back face of the waveguide, and the output fields have 3 fold rotational symmetry. Moreover, the total intensity of the three beams consists with the intensity of the input field, these are displayed in Fig(4). Fig.5(a) demonstrates the similar results when the input field is launched in the other location, for example the location of (0, 3a 4) .However, if the position of the input field is located in the center of the waveguide (0, 3a 3) , the only one output beam is still located the center, Fig.5(b) shows the result, which is because some of images overlap with each other.
Fig. 4. The field at the distance z = L0 3
Fig. 5. The incident wave launched at the
(0, 3a 4) and (0, 3a 3)
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Finally, the field distribution at the distance z = L0 9 are calculated and displayed in Fig(6). The incident light is splitted into nine identical and symmetrical distributions when the incident light is launched at (0, 3a 6) as shown in Fig.6(c); while the incident light is launched at (0, 3a 4) , the initial wave is splitted into twenty-seven identical and symmetrical distributions, Fig.6(d) shows the result. So the number of the output beams is decided by the location of the incident light. We consider the initial wave can split into twenty- seven at this distance, if the number is less than twenty-seven, that is because some of images overlap with each other. (Note that: Fig.6(d) takes GBP with a waist size of ω 0 = 6 μm to avoid superposition of the field).
Fig. 6. The field at the distance z = L0 9 : (c) the incident wave launched at the (0, 3a 6) ; (d) launched at the (0, 3a 4)
A splitting of the field distributions in waveguide is well known phenomenon, this phenomenon can be used for beam splitters. The main difference between the waveguide beam splitter and other beam splitter is that it can provide many output beams with the same intensity. Another nice property of the ETW beam splitter or the difference between the ETW beam splitter and the other waveguide beam splitter is that the ETW beam splitter can provide 3 n (n = 0,1,2 ") beams with the 3 fold rotational symmetry. So the interesting application of the results as demonstrated in this work is useful in designing a new beam splitters.
4 Conclusion Summarizing, from above discussed, an optical beam splitter bases on ETW formed when the length of the waveguide and the location of identical light are appropriate. When the length of the ETW is one third of the self-imaging length, the incident light is divided into three identical and symmetrical beams; while the length of the ETW is one nine of the self-imaging length, the incident light is divided into twenty- seven identical and symmetrical beams, if the number is less than twenty-seven, that is because some of images overlap with each other. It is expected that the results obtained here will help to design a new splitter.
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References [1] Ovchinnikov, Y.B.: Revivals of light in a planar metal waveguide. Optics. Communications 182, 35–43 (2000) [2] Ovchinnikov, Y.B., Pfau, T.: Revivals and oscillations of the momentum of light in a planar multimode waveguide. Physical. Review. Letters 87, 123901 (2001) [3] Ovchinnikov, Y.B.: A planar waveguide beam splitter. Optics.Communications 220, 229–235 (2003) [4] He, S.L., Ao, X.Y., Romanov, V.: General properties of NM self-images in a strongly confined rectangular waveguide. Applied. Optics 42, 4855–4857 (2003) [5] Wu, C.Y., Somervell, A.R.D., Barnes, T.H.: Direct image transmission through a multimode square optical fiber. Optics. Communications 157, 17–22 (1998) [6] Wu, C.Y., Somervell, A.R.D., Haskell, T.G.: Optical sine transformation and image transmission by using square optical waveguide. Optics. Communications 175, 27–32 (2000) [7] Sun, Y.L., Jiang, X.Q., Yang, J.Y., Tang, Y., Wang, M.H.: Experimental demonstration of two dimensional multimode-interference optical power splitter. Chinese Physics Letters 20, 2182–2184 (2003) [8] Han, Z.H., He, S.L.: Multimode interference effect in plasmonic subwavelength waveguides and an ultra-compact power splitter. Optics Communications 278, 199–203 (2007) [9] Zhang, Y.W., Liu, L.Y., Wu, X., Xu, L.: Splitting-on-demand optical power splitters using multimode interference waveguide with programmed modulations. Optics Communications 281, 426–432 (2008) [10] Ma, Z.T., Ogusu, K.: Power splitter based on cascaded multimode photonic crystal waveguides with triangular lattice of air holes. Optics Communications 282, 3473–3476 (2009) [11] Li, W., Xu, X.M.: An ultra-short double-wavelength optical power splitter for two waveguides operation based on photonic crystal multimode interference. Optics Communications 5, 69–73 (2010) [12] Huang, Y.Z.: Eigenmode confinement in semiconductor microcavity lasers with an equilateral triangle resonator. In: Proceedings-SPIE The international society for optical., vol. 239, p. 3899 (1999) [13] Guo, W.H., Huang, Y.Z., Wang, Q.M.: Resonant frequencies and quality factors for optical equilateral triangle resonators calculated by FDTD technique and the Padeapproximation. Photonics Technology Letters, IEEE 12, 813 (2000) [14] Huang, Y.Z., Guo, W.H., Wang, Q.M.: Analysis and numerical simulation of eigenmode characteristics forsemiconductor lasers with an equilateral triangle micro-resonator. Journal of Quantum Electronics, IEEE 37, 100 (2001) [15] Wysin, G.M.: Resonant mode lifetimes due to boundary wave emission in equilateral triangular dielectric cavities. Journal of optics A: Pure and Applied. Optics 7, 502–509 (2005) [16] Huang, Y.Z., Guo, W.H., Yu, L.J., Lei, H.B.: Analysis of semiconductor microlasers with an equilateral triangle resonator by rate equations. Journal of Quantum Electronics 37, 1259–1264 (2001) [17] Isaac, G., Khalil, D.: Ray optics model for triangular hollow silicon waveguides. Applied Optics 45, 7567 (2006)
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[18] Liu, Z.M., Zhu, K.C., Tan, B., Hao, Z.Q., Wen, W.: Image transmission through a mental equilateral triangle waveguide. Chinese Journal of Quantum Electronics 24, 253–256 (2007) (in chinese) [19] Doncheski, M.A., Robinett, R.W.: Quantum mechanical analysis of the equilateral triangle billiard: periodic orbit theory and wave packet revivals, 8 (2003), arXiv: quantph/0307063 [20] Lin, S.L., Gao, F., Hong, Z.P., Du, M.L.: Quantum spectra and classical orbits in twodimensional equilateral triangle billiards. Chinese. Physics. Letter 22, 9–11 (2005)
Analysis and Implementation of Embedded SNMP Agent Hubin Deng, Guiyuan Liu, and Lei Zhang College of Information Engineering, East China Jiaotong University, Nanchang, P.R. China [email protected]
Abstract. With the extensive application of network devices and the rapid development of embedded technology, network management of embedded devices becomes increasingly complicated. SNMP management is the most widely used network management system(NMS). Most of the network components used in enterprise network have built-in network agents that can respond to an SNMP network management system. By analyzing the SNMP (Simple Network Management Protocol) and base on NET-SNMP development kit, discuss the construction of MIB modules and code conversion and complete embedded SNMP Agent extension. Through network management tools to verify the SNMP agent on the network management functions of the embedded device. Keywords: Embedded technology, Network management, SNMP Agent, MIB modules, NET-SNMP development kit.
1 Introduction Along with the popularization of the network application and the network equipment, it is also gradually increasing to the network management demand. Because Simple Network Management Protocol(SNMP) has obtained the widespread application in the industrial world by its simplicity. The TCP/IP major part router and the switchboard all support SNMP in the protocol standard certain main management information database (MIB). In addition, in other private network equipment management domain, the SNMP network management has also obtained the widespread application. In the SNMP management model, the management station is carries on the management and the monitoring center to AGENT, Agent is managed to the equipment to carry on the monitoring and front end the operation network management. Therefore, in the network equipment, to increase SNMP the network management to act AGENT adapts the network supervising and managing development essential work. This article takes SNMP and the existing system resources as a foundation, analyzes the embedded SNMP proxy software with emphasis of the function module, with the aid of opens source tool development package NET-SNMP, has constructed the MIB storehouse module, and has developed the embedded equipment SNMP agent software. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 96–102, 2011. © IFIP International Federation for Information Processing 2011
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2 Simple Network Management Model Simple Network Management Protocol (SNMP) is a UDP-based network protocol. It is used mostly in network management systems to monitor network-attached devices for conditions that warrant administrative attention. SNMP management is also referred to as Internet management. It’s called SNMP management because it has matured to the level that it manages more than the Internet, for example, intranet and telecommunication networks. Any network that uses the TCP/IP protocol suite is an ideal candidate for SNMP management. SNMP network management system can manage even non-TCP/IP network elements through proxy agents. The SNMP management consist four elements: Network Management System (NMS), Agent, Management Information Base (MIB), and Simple Network Management Protocol (SNMP). It uses the concept of Client/Server application. A network management system (NMS) executes applications that monitor and control managed devices. On each manageable equipment, a SNMP Agent is running. This agent manages information relating to the equipment which is stored in a local database called the MIB.And the SNMP Protocol is used to connect the NMS and the Agents. SNMP is a protocol built on the top of UDP/IP: The architecture specifies the management messages between the management system and the management agents. 5 types of SNMP messages or SNMP requests can be exchanged (SNMPv1) between a SNMP agent and a SNMP manager: 1. Obtaining the current value of a MIB object managed by an agent: request getrequest (GET). 2. Obtaining the current value of the next MIB object managed by an agent: request get-next-request (GETNEXT). 3. Updating of the current value of a MIB object managed by an agent: request set-request (SET). 4. Sending back the value of a MIB object managed by an agent: request getresponse . It's the answer to a GET, GETNEXT or SET request. One can see that SNMP is a command/response protocol without state. 5. Signal/alarm emitted by an agent to a manager: message trap (TRAP). Agent
Management get-request
get-response 8'33257 get-next-request get-response set-request
8'33257 8'33257
get-response trap 8'33257
Fig. 1. Five types of SNMP Operation
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3 MIB Module Design and Code Conversion SNMP itself does not define which information a managed system should offer. Instead, SNMP uses an extensible design, where the available information is defined by management information baes(MIB). MIB describe the structure of the management data of a device subsystem; they use a hierarchical namespace containing object identifiers (OID). Each OID identifies a variable that can be read or set via SNMP. MIB use the notation defined by ASN.1.
Fig. 2. Definiton(skeletal) of SMI for SNMP v2
In telecommunications and computer networking, Abstract Syntax Notation One (ASN.1) is a standard and flexible notation that describes data structures for representing, encoding, transmitting, and decoding data. It provides a set of formal rules for describing the structure of objects that are independent of machine-specific encoding techniques and is a precise, formal notation that removes ambiguities. ASN.1 is defined as a set of rules used to specify data types and structures for storage of information. Basic Encoding Rules (BER) is defined for the transfer syntax by the ASN.1 syntax. The syntax to create a SMIB module is referred to the description section in SMI(Structure of Management Information). In this paper, MG-SOFT is used to define a MIB document in ASN.1. MG-SOFT's MIB tools are quite mature and widely used for SNMP development and testing. Its MIB Browser can not only read and write MIB, but also receive the Trap sent by SNMP agents; MIB Compiler can be used to check the legality of MIB, which is useful for the compose of MIB. This MIB document is then transformed into the C language source file by MIB2C.MIB2C is a useful software tool in NET-SNMP. Follow these steps to convert: First of all copy the MIB module definition files to the mibs directory: cp./modulename /usr/local/share/snmp/mibs; Then, run MIB2C command: /Usr/local/bin/mib2c modulename to translate; Finally, MIB2C generated in the current directory two C source files: modulename.h and modulename.c. These two documents are made under the MIB library
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module conversion, and also need to be added to the NET-SNMP SNMP Agent Software to extensions of the source code.
4 SNMP Entity and AGENT Extension The SNMP Agent consists of a dispatcher, a message processing subsystem, and a securtiy subsystem. The SNMP Agent consists of a dispatcher, a message processing subsystem, and a securtiy subsystem. The SNMP message processing subsystem of an SNMP engine interacts with the dispatcher to handle version-specific SNMP message. It contains one or more message processing models. The version is identified by the version field in the header. The security and access control subsystem provides authentication and privacy protection at he message level. The access control subsystem provides access authorization security. SNMP Entity
Fig. 3. SNMP Agent Entity
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There is only one dispatcher in an SNMP engine, but it can handle multiple versions of SNMP message. It performs three sets of functions. First, it sends message to and receives message from the network. Second, it determines the version of the message and the interacts with the corresponding message processing model. Third, if provides an abstract interface to SNMP applications to deliver an incoming PDU to the local application and to send a PDU from the local application to a remote entity. To complete the SNMP Agent to a embedded device takes the steps as follows: In the net-snmp-5.4.2.1 directory configure: ./ Configure - host = arm-linux target = arm --With-cc = /armv4l-unknowlinux-gcc - -with-ar = arm-linux-ar --disable-shared - with-endianness = little-With-mibmodules = "moudlename". In the net-snmp-5.4.2.1 directory, compile: make. In net-snmp-5.4.2.1/agent directory, you can see the generated snmpd process, as shown below: Copy the snmpd program to the development board "/ usr / bin" directory and start with the following command: /usr/bin/snmpd –V –c /etc/snmpd.conf.
Fig. 4. Run the snmpd programe
5 Conclusion The SNMP protocol was developed to facilitate the network management. In this paper the free software package, NET-SNMP is used to extend the NET-SNMP agent to an embedded system under the ARM-LINUX OS in order that the embedded can be controlled remotely by SNMP NMS.NET-SNMP makes it possible to integrate an embedded system into a network and to manage it with SNMP managers like MGSOFT. The Management station's IP is 192.168.2.4,and the embedded equipment's IP is 192.168.2.120.The testing result of verifying the embedded SNMP agent shows as in Figure 5.
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Fig. 5. Verify the SNMP agent
Acknowledement This work was sponsored by the technology proliferation plan item of Nanchang city (Caiqi[2008], NO.68), science and research foundation of East China Jiaotong University(09XX05).
References [1] Rose, M.T., McCloghrie, K.: RFC1155 Structure and identification of management information for TCP/IP-based internets (May 01, 1990) (for the complete set of data types) [2] Case, J.D., Fedor, M., Schoffstall, M.L., Davin, C.: RFC1157 Simple Network Management Protocol (SNMP) (May 01, 1990) (Obsoletes RFC1098) [3] McCloghrie, K., Rose, M.T.: RFC1213 Management Information Base for Network Management of TCP/IP-based internets: MIB-II (March 01, 1991) (Obsoletes RFC1158) (Updated by RFC2011 RFC2012, RFC2013) (Also STD0017) [4] Case, J., McCloghrie, K., Rose, M., Waldbusser, S.: RFC1905 Protocol Operations for Version 2 of the Simple Network Management Protocol (SNMPv2).SNMPv2 Working Group (January 1996) [5] Subramanian, M.: Network Management Principles and Practice. Higher Education Process Pearson Education, Beijing (2001) [6] Comer, D.E.: Automated Network Management Systems. Machinery Industry Press, Beijing (2008) [7] Wang, S., Li, T.: Application of SNMP on VxWorks Embedded Operation System. Micro Computer Information 21(5), 86–87 (2004)
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[8] Richardson, P.C., Xiang, W., Mohamad, S.: Performance Analysis of a Real·-time Control Network Test Bed in a Linux–based System with Sporadic Message Arrivals. IEEE Transactions Oil Industrial Informatics 2(4), 231–241 (2006) [9] Fu, G., Yang, W.: Research on scheme of intelligent network management. Journal of Xi’an University of Engineering Science and Technology 19(1), 89–92 (2005) [10] Stallings, W.: SNMP and SNMPv2.The infrastructure for network management. Communications Magazine, IERE 36(3), 110–115 (2008)
Application of Computer Technology in Advanced Material Science and Processing Yajuan Liu* SoftSchool, East China JiaoTong University, Nanchang, P.R. China Tel.: +86-791-7046184; Fax: +86-791-7046185 [email protected]
Abstract. Computer technology is an actual system model, which is largely unaffected by experimental conditions, time and space constraints, and is of great flexibility. Nowadays, computer technology has thoroughly penetrated in the various areas of material processing and research, which becomes one of the important frontiers in the field of material manufacturing industry. At the same time, material science and technology are also developing rapidly and constantly giving birth to the new industrial field, such as nanotechnology, optoelectronic, magnetic electronic technologies, which are inseparable of computer technology. Hence, in this article, the application of computer technology in advanced material science and processing, which includes material science database, computational material science, computer-aided design or processing etc are reviewed. Keywords: Computer Technology, Material Processing, Material Science.
1 Introduction With the continuously deepening research of material science, material science occupies an important position in the national economy; however, material science is still an immature interdisciplinary, which mainly depends on the facts and the experience of the current study. The systematic studies need a very long process[1]. Computer as a modern tool plays an increasingly significant role in various areas of the world, which has penetrated into many fields. With respect to the material science and engineering, the computer is also becoming a very important tool and becomes one of the reasons for the accumulation of the rapid development of material science. For example, computer technology has been widely used in the variety field of material forming technology, including application in liquid forming, plastic forming, polymer material forming, powder forming et al, which can basically provide a qualitative description toward to quantitative prediction for material processing[2-3]. Furthermore, computer application in material science is the trend of multi-scale simulation and integration[4-5]. In this *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 103–107, 2011. © IFIP International Federation for Information Processing 2011
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article, the application of computer technology in material science and processing including material science literature search practice, computational material science, computer-aided design and processing are mainly introduced.
2 Computer Technology in Material Science Databases A reasonable choice of material, accurate design and scientific processing are directly impacting on product cost and quality, which even affect the social development and progress. In recent years, with computer technology development, particularly in the development of database technology, material science databases in scientific research has become increasingly emphasized and get more and more widely used. A sample material database was illustrated in Figure 1.
Fig. 1. A sample of material database
Material science database can be divided into the data type, numeric type as well as the map database. Otherwise, it is also divided into the online and offline database type. The literature database is of mainly online services, while numerical databases were more used in off-line. Moreover, according to the point view of material, it can be classified into metallic and nonmetallic material databases. Public material databases have been constructed every year and the developed countries continue to make the information on this strategic. Numeric material database has been established in China since 1992 and has accumulated in recent years[6]. Though after several decades of development and accumulated, however, the following deficiencies still exist: (1) The lack of the data of mechanical properties. In the development of metallic material database, it focuses on the iron and steel materials,
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however, with respect to the light alloys such as aluminum, magnesium alloys, it was still lack of the mechanical properties' database.(2) The lack of the data of material processes performance. Cold and hot processing of material data is rarely found. (3) Although some scientific databases of materials have built at home and abroad, its research and development still lags far behind the actual rate of application requirements. Generally, network, standardization, intelligence and commercial trends will make the application material database, extended to broader areas of material research and development.
3 Computational Material Science Computational material science (CMS) is a typical interdisciplinary of material science and computer science, which is the material scientific research about the “computer design” and “computer experiment” in material composition, structure, performance, service performance[7]. According to the literatures[8], CMS could be mainly included into two aspects: one is calculation and simulation, which is starting from the experimental data, through the establishment of mathematical models and numerical calculations to simulate the actual process; the other is the computer added material design, which is directly through the theoretical model to calculate, predict or design the new structure and properties of material. Therefore, CMS is a bridge to connect theory and experimental material. It is well known that the material composition, structure, performance and service performance are the four elements of material research. The traditional research is based material experimental results in the laboratory, which is an experimental science. However, with the requirements of high material performance increasing, especially because the material sciences research object is constantly changing spatial scale into small, the micro-level studies do not reveal the nature of material properties, nano-structures and atoms scale and even electronic level become the studied content when the functional material are studied[9]. Therefore, material research is increasingly dependent on high-level testing technology, the research difficulty and costs are getting much higher. In addition, the service performance is increasing attention in material research, which is to study the interaction of material and service environment and its impact on material performance. As the material was serviced in an increasingly complex environment, laboratory studies of service performance have become more and more difficult. In short, it was difficult that the new and modern material research and development relying solely on laboratory experiments to conduct material research. Computer simulation technology, however, according to the basic theory, from the inclusive concept of a virtual environment, micro-, meso-, macro-scale, multi-level research on the material in the computer, but also can simulate the ultra-high temperature, high pressure material under extreme environments such as service performance to simulate material properties under service conditions, failure
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mechanism, so as to realize the performance of material in service improvements and material design. Thus, in the field of modern material science, the computer "experiment" has the same important position in research methods. It is necessary to point that CMS is closely related to computer development. In the past, even if the use of large computers is also very difficult to calculate a number of materials, such as material, quantum mechanic calculations, now it can complete this on PC. In addition, with the continuous progress of CMS and mature, material, computer simulation and design is no longer a hot research topic of just theoretical material physics and material scientists calculated, but also will become an important research tool of general-purpose material researchers.
4 Computer Aided Design and Manufacture The initial processing of computer used for complex engineering analysis and calculation is followed by the development process in the modern industrial product design, such as the aircraft surface flow field calculation, the stress analysis of the complex structure[10]. The system can do a lot of complex calculations in a very short period of time, and it is possible for many programs for rapid analysis and evaluation to choose the best design. Material processing CAD can be divided into casting CM, plastic forming CAD, welding forming CAD, injection molding CAD, as well as mold CAD[11]. The computer simulation of casting process was carried out earlier and the technically is more mature, which has been into the micro-macro simulation stage. From the early 90's in 20 centuries, it has launched the computer simulation of micro-morphology, in which it can simulate the nucleation, growth the process of casting solidification process of forecasting[12-14]. After years of research and development, a large number of casting process simulation software has been the commercialization, which is shown in Table 1[15]. Table 1. Overview of main foreign casting special software Software name Mavls software
Developer Alphacast software Ltd
Flow-3d
Flow science, Inc
ProCast
UES software,Inc
Cast CAE4
Finland
Function Predicted melt flow temperature, pressure, velocity distribution, macro-and micro-shrinkage, dendrite arm spacing, steady-state temperature distribution Automatically predicted solidification shrinkage, binary segregation and tracking of surface defects formation of micro-structure such as porosity, pore aggregation Calculated solidification shrinkage, formation of 3-D view
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5 Conclusion In summary, material science is a cross-emerging for the development of immature discipline. At present, its research is largely depended on the facts and the experience. The systematic studies need a very long process. The computer is becoming an extremely important tool, which is one of the important reasons for rapid development of material science. The use of computers for design of new material has gradually been recognized and used. However, this understanding and effort are still insufficient. Facing the future, computer simulation technology, material calculation and design will become an inevitable trend.
References 1. Flaszka, W.G., Paro, J.A., Kivivuori, S.O.J.: Computer-aided forging design using model material simulation. J. Mater. Process. Technol. 24, 403–409 (1990) 2. Joshi, K., Lauer, T.W.: Impact of information technology on users’ work environment: A case of computer aided design (CAD) system implementation. Inf. Manage. 34, 349–360 (1998) 3. Sapuan, S.M.: A knowledge-based system for material selection in mechanical engineering design. Mater. Des. 22, 687–695 (2001) 4. Gates, T.S., Odegard, G.M., Frankland, S.J.V., Clancy, T.C.: Computational materials: Multi-scale modeling and simulation of nanostructured materials. Compos. Sci. Technol. 65, 2416–2434 (2005) 5. Hao, S., Liu, W.K., Moran, B., Vernerey, F., Gregory, B.O.: Multi-scale constitutive model and computational framework for the design of ultra-high strength, high toughness steels. Compos. Methods in Appl. Mech. Eng. 193, 1865–1908 (2004) 6. http://www.csdb.cn/viewdb.jsp?uri=cn.csdb.material 7. Sokrates, T.P.: Frontiers in computational materials science. Compos. Mater. Sci. 2, 149–155 (1994) 8. Richard, P.M.: Computational materials science -a personal perspective of an industrial scientist. Compos. Mater. Sci. 2, 161–167 (1994) 9. Hafner, J.: Atomic-scale computational materials science. Acta Mater. 48, 71–92 (2000) 10. Wan, H.: Application of computers in materials science. Sci. Technol. of Aotou Steel Corp. 31, 6–9 (2005) 11. Bata, G.L., Salloum, G.: Computer integrated material processing (CIMP) -A generic application of CAD/CAM technology. Mater. Des. 8, 220–228 (1987) 12. Jerald, R.B., Sanjay, J., John, W.D., Srinivas, P.: Application of computer-aided engineering techniques to tooling for castings. J. Manuf. Syst. 11, 215–223 (1992) 13. Im, Y.T.: A computer-aided-design system for forming processes. J. Mater. Process. Technol., 89–90, 1–7 (1999) 14. Karima, M., Richardson, J.: A knowledge-based systems framework for computer-aided technologies in metal forming. J. Mechan. Work. Techn. 15, 253–273 (1987) 15. Cao, H.J., Song, Y.P., Wang, W.Y.: The application and development of Computer Simulation of Casting Process. J. Henan Univ. Sci. and Techn.: Nat. Sci. 27, 5–8 (2006)
Application of Interferometry in Ultrasonic System for Vibration Zhengping Liu, Shenghang Xu, and Juanjuan Liu School of Mechatronical Engineering, East China Jiaotong University, Nanchang, 330013, P.R. China [email protected]
Abstract. Vibration signals are important state parameters for mechanical equipments’ status monitoring and fault diagnosis. In this paper, in order to overcome the limitations of the traditional vibration measurement med1ods and instrument, a new non-contacting vibration method based on ultrasonic for vibration detection in special environment was presented. The mainly researched in this paper were the circuit for ultrasonic transmitting, receiving, algorithm and the module based on LabVIEW for signal analysis and processing. New algorithm was adopted in the system design. The measurement for vibration signals, which may have higher accuracy, was based on ultrasonic wave of different frequency. Experiments were carried on for proving the theory and the result was expected, verifying the reliability and feasibility of the system. Keywords: Vibration Signal, Ultrasonic, Signal Processing, Fault Diagnosis.
1 Introduction Vibration signals are important state parameters for mechanical equipments status monitoring and fault diagnosis. The method of vibration signals measurement is very limited. Such as displacement sensor, speed sensor and acceleration sensor, they are limited of itself. Most of the sensors are mounted to measure the objects. Testing vibration on Eddy current sensor is a noncontact system, but the distance is very limited. The traditional vibration measurement med1ods and instrument can not achieve effective measurement in HTHP industrial environment. A new non-contacting vibration method based on ultrasonic for vibration detection is completed high precision, long-distance measuring in special environment.[1] To overcome the limitations of the traditional vibration instruments, a noncontacting vibration method based on ultrasonic for vibration detection in HTHP environment was presented in this paper. The noncontact system of vibration measurement is based on optical interferometry. Ultrasonic has advantages such as high frequency, shorter wave-length, steady direction of propagation, and easily obtainment of directional and focused ultrasound beam. The principle of the vibration measurement system is based on Doppler. A continuous wave ultrasonic beam is transmitted toward the vibrating surface, and the ultrasound signal reflected by this moving surface is sensed by a second transducer. The received ultrasound signal is D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 108–115, 2011. © IFIP International Federation for Information Processing 2011
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phase modulated. Therefore, features can be extracted from the vibration signal by analyzing the factors that affect the variations of traffic load.
2 Method The method of the vibration measurement system is based on the phase. The schematic diagram of the ultrasonic system for vibration measurements is given in the Fig.1., y(t) and y(r) are respectively the transmit signal and the receive signal. In operation, the ultrasonic transmitter transmits y(t) continuously and the ultrasonic receiver will simultaneously receives y(r) reflected by the object. Besides, the w is the angular frequency of ultrasonic wave, the C is speed of ultrasonic wave, and the L(t) is distance between the ultrasonic transducers and the measured object.[1] The transmitted and the received wave forms are given by
y (r ) = sin( wt + φ )
(1)
y (t ) = sin wt
(2)
The distance that the signal spreads from transmitting transducer to receiving transducer is 2 L(t). The L(t) depends on effective vibration length d(t). The change of phase Φ(t) is determined by the formula,
φ (t ) =
2 L(t )
λ
∗ 2π
(3)
The effective vibration length is determined by the formula,
d (t ) = ΔL(t ) =
Δφ (t ) λ 2π 2
(4)
The λ is the wavelength of the ultrasonic wave used in this system; the Φ(t) is the change of phase and it is changed among 0 to 2π ; the Φ(t) depends on the effective vibration length d(t). The peak amplitude dmax is peak amplitude of the ultrasonic wave. The θ has some repeated and the d(t) is not judged when the d(t) exceeds the length of λ/2. So the d(t) is bounded by λ/2 and the D(t) that it .the d(t) is bounded by λ/2 that is defect. To overcome this limitation, an effective algorithm was selected and low frequency wave and high frequency wave was adopted in this paper. The low frequency wave has large wavelength, so that the measurement range was increased. The high frequency wave has high frequency, so that the measurement precision is improved. The total displacement D(t) is determined by the formula, D(t)=2 d (t ) = ΔL(t ) =
θ Δφ (t ) ∗λ =n∗λ + ∗λ 2π 2π
(5)
The θ1 is the phase shift and its value usually cycles between zero to 2π. As shown in the Fig.2., the D is the total displacement, the θ1 is the phase, the λ1 is the wavelength
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and the f1 is frequency of the low frequency wave. The total displacement D(t) is determined by the formula,
θ1 ∗ λ1 2π
D (t ) = D1(t) =
d
L
(6)
d
R
T D
Fig. 1. Schematic diagram of ultrasonic system for vibration measurements
The θ2 is the phase, the λ2 is the wavelength and the f2 is frequency of the low frequency wave. The θ2 is a greater phase shift than phase frequency of the f1 because the f2 is greater than the f1. The integer number N2 of wavelength of frequency f2 signal can be calculated from N2=Int[D1/λ2]. The total displacement D(t) is determined by the formula, D(t)=D2(t)= N 2 ∗ λ 2 +
θ2 ∗ λ2 2π
D
2π θ1
λ1 2π
n
θ2
λ2 Fig. 2. Schematic diagram of the method
(7)
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The final equation concluded from the above equations is shown as follows, D(t)= Int[D1/ λ 2 ]* λ 2 +
= Int[
θ2 θ θ 1 ∗ λ 2 = Int[ 1 ∗ λ1 ∗ ]* λ 2 + 2 ∗ λ 2 2π λ2 2π 2π
θ1 f 2 c c θ2 ∗ ]* + ∗ 2π f 1 f 2 2π f 2
(8)
where c is the speed of sound. The frequencies of 10 kHz and 40kHz are chosen in the experiment. So, the maximum distance is 1.70 cm.[1],[2],[3],[4]
3 The Hardware System Architecture The hardware of the vibration measurement system consists of two ultrasonic transducers, for transmitting and receiving the signals, and the circui for ultrasonic transmitting and receiving signal processing. The part completes signal acquisition and processing function automatically. 3.1 Design of Transmission Circuit The design of the circuit for ultrasonic transmitting adopted NE555 time-based circuit and also the peripheral circuits and the more harmonic oscillator circuit.The circuit of NE555 time-based worked for the setting and reset alternately repeatedly on without the steady-state operation mode. The 3 pin of output terminal is outputting utalternate with low level and high level, the output waveform approximated rectangular wave. There are many kinds of ultra harmonics of rectangular, therefore, the circuit without the steady-state operation mode can be called multi vibrator as self-excitation.[4],[5] As shown in the Fig.3., the circuit for ultrasonic transmitting consists of the circuit of NE555 time-based and the correlative circuit. The output of capacitor C1 is unchanged. The 2 pin of NE555 outputs low level, the 3 pin of NE555 outputs high level and inward transistors are in off condition. The 7 pin is impending and the capacitor C1 is charged by VDD. Then, the voltage of C1 is building up. The VC1 reaches the threshold level 2VDD/3 after a time of T1. So, now the circuit of NE555 time-based has overturned and reseted. Then the 3 pin outputs low level, and the inward transistors are in conducting state. The 7 pin outputs low level, the capacitor C1 is discharging. When the VC1 is droping to VDD/3 after T2, the circuit of NE555 time-based has overed and reseted, and the 3 pin outputs high level and the 7 pin is impending again, circulate down so. So the 3 pin can output a rectangular wave. The T1 of high-level outputs charging time is determined by the formula,
t1 = −(R1 + R2 )C1 ln[(VDD − 2VDD / 3) /(VDD −VDD / 3)] = ( R1 + R2 )C1 ln 2 = 0.693( R1 + R2 )C1
(9)
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VCC C3 100pF
8
R1 4
5K
7 R2
6
1.5K
NE555
3
2
C1 100pF
1
5
R 20K
C2 100pF
UCM40T
Fig. 3. The circuit for ultrasonic transmitting
The T2 of low-level outputs charging time is determined by the formula,
t 2 = 0.693R 2 C1
(10)
The cycle time of rectangular wave is determined by the formula,
T = t1 + t2 = 0.693( R1 + 2 R2 )C1
(11)
The oscillation frequency f ,
f = 1 / T ≈ 1.44 /( R1 + 2 R2 )C1
(12)
The dutyfactor D of output pulse is determined by the formula,
D = ( R1 + R2 ) /( R1 + 2 R2 )
(13)
The output is a square wave signals when the R2 is much greater than the R1 and the duty factor D equals to 50%. The oscillation frequency f is up to R1 and R2 to determine. Center-frequencys of the ultrasonic transmitter are respectively 40 kHz, 10 kHz. When the center-frequency is 40kHz, the C1 is 0.1μF, and the resistances of R1 and R2 are respectively 0.6k Ω and 1.5k Ω . When the center-frequency is 10kHz, the C1 is 0.1μF, Resistances of R1 and R2 are respectively 1k Ω and 72k Ω . 3.2 Design of Receiving Circuit As show in the Fig.4., the circuit for ultrasonic receiving, that in which signal amplification, filtering, DC signal eliminating are included, has function of signal processing, avoiding the shortcomings of feeble signal and noise. The 2 stage signal amplification
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system was adopted in this experiment. The signal that is processed is deduced to PC computer. The signal can be shown by the software system. The circuit for ultrasonic receiving can be used in combination with the circuit for ultrasonic transmitting. The circuit is composed of four parts: the amplifying circuits A1 and A2, the rectifying circuit R3, the filter circuit RC, and the comparator circuit A4. The filter circuit has frequency selectivity that it amplifies 40 kHz signal and the yield value equals to 5. Multistage filter circuit was adopted. The half-wave rectifying circuit consists of operational amplifiers. The cut-off frequency of the filter circuit is 40 kHz. The comparator circuit also consists of operational amplifiers.
4 Testing The system for experiment was composed of three parts: the hardware of the system, the interface circuit and the software of the system. +15
C D 5 C
R
6
R
R
R out2
+
R
5
7 R
C
R PR
6
out2 +
5
7 R
6
out2
5
7
+
D C+
6
out2
7
OUT
+
R PR GND
Fig. 4. The circuit for ultrasonic receiving
The experimental facility included a flexible manipulator, a vibration exciter, two ultrasonic transducers, various circuits and a data acquisition card. The vibration source consists of the flexible manipulator that was driven by vibration exciter. The vibration exciter was adjusted among 20 to 20 kHz.The date was gathered by the multifunction data acquisition card which is made in the NI Company. The system of software can realize the real-time signal ongoing acquisition and storage. The change of phase is transformed into the visualization function graphic of D(t). The software extracted effectively characteristic value of the vibration signal.4,5 The frequency of the excitation signal in the experiment was selected at 71.2Hz. The irregular original signal was provided in Fig.5. In addition, Fig.6. gives the changing law of phase-shifts. After the collection and analysis of the phase-shifts change, completed vibration signal will be obtained, as well as the characteristic value. However, when the amplitude of the flexible manipulator is too large, the changing signal of phase shift signals confusion and cannot be measured then, as show in Fig.7.
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Fig. 5. Original signal oscillogram
Fig. 6. Phase-shifts D(t) oscillogram
Fig. 7. Phase-shifts D(t) oscillogram when the amplitude is too large
5 Conclusion With the new system, which is based on vibration detection with ultrasonic wave, designed in this paper, remote objects can be detected on the vibration, overcoming the limitations that contact measurement has, such as piezoelectric sensors etc. The new system can also be applied to low frequency vibration measurements, with a much wider measurement range than the eddy current sensor. Here, no accessory is needed to be mounted on the vibrating object, avoiding the influence of vibration objects. The measurement technique based on the ultrasonic wave is a supplement for non-contact vibration measurements. It has many advantages such as low cost, convenient operation, high test speed, and so on. So that this measurement technique has much potential applicative value for condition monitoring of some industrial machinery equipments, especially for application in vibration measurement of fine structure or in some special working environment, such as high temperature, high pressure, dust, strong corruption,
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non-Contact and so on. Certainly, there are some shortcomings of this measurement technique. Great restrictions are still existed for the amplitude of vibration, not being solved completely. Continue study and further improvement are still needed in the future.
References 1. Meng-Hsiang, Y., Huang, K.N., Huang, C.F.: A Highly Accurate Ultrasonic Measurement System For Tremor Using Binary Ampltude-Shift-Keying And Phase-Shift Method. Biomedical Engineering-Applications 15(2), 15–21 (2003) 2. Ngoi, B.K.A., Venkatakrishnan, K.: An AcoustoOptic Vibrometer for Measurement of Vibration inUltraPrecision Machine Tools. Int. J. Adv. Manuf. Technol. 16, 830–834 (2000) 3. Soon, W.H., Ho, C.L., Yoon, Y.K.: Non-contact Damage Detection of a Rotating Shaft Using the Magnetostrictive Effect. Journal of Nondestructive Evaluation 22(4), 141–150 (2003) 4. Fernando, F., Enrique, B.: Member, An Ultrasonic Ranging System for Structural Vibration Measurements. IEEE Transactions on Instrumentation and Measurement 40(4), 1991–1997 (1991) 5. Matar, O.B., Remenieras, J.P., Bruneel, C., Roncin, A., Patat, F.: Noncontact Measurement of Vibration Using Airborne Ultrasound. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 45(3), 626–634 (1998)
Automatic Control System for Highway Tunnel Lighting Shijuan Fan, Chao Yang, and Zhiwei Wang School of Mechatronic Engineering, East China Jiaotong University, Nanchang, P.R. China
Abstract. To solve the problems such as driving safety and energy consumption existing in tunnel lighting control system, an automatic control system of tunnel lighting is designed based on stepless control method. The tunnel lighting control model is established based on “Specifications for Design of Ventilation and Lighting of Highway Tunnel (China)”. Simulation experiment of tunnel lighting control based on the established stepless control model is completed with Matlab. Compared with theoretical luminance data, simulation results show that the automatic control system can meet the luminance requirements of actual tunnel lighting, the error can be controlled less than 2%. Compared with HPS (high pressure sodium) lamps and LED (light-emitting diode) lamps with the consideration of maximum lighting value, the stepless controlled LED lamps can save more than 80% and 35% energy than HPS lamps and LED lamps respectively, and can save more than 20 % energy than 4-steps controlled LED lamps. Keywords: tunnel lighting, automatic control system, stepless control method, continuous light tuning, energy-saving.
1 Introduction China social economy and traffic undertaking are developing rapidly, tunnel traffic is becoming more and more necessary and important in mountainous areas of China, but the operating cost of tunnel traffic is huge, how to improve traffic safety performance and reduce operating cost of the tunnel traffic has become a focus issue that the China's transport department concerned. Tunnel lighting is an indispensable part to ensure driving safety and normal operation in tunnel traffic, and also is a key factor to reduce tunnel interior energy consumption [1]. Therefore, the corresponding design specifications about tunnel lighting are issued in various countries, such as CIE (Commission International d'Eclairage), BS (Britain lighting standards) and IES (Illuminating Engineering Society of North America), etc[2]-[4]. To establish a safe, economical and energy-saving tunnel lighting system has important significance for sustainable development of China’s highway engineering. Design quality of tunnel lighting control system determines whether tunnel lighting design is excellent or not. The existing control methods include manual control, sequential control and automatic control methods. Manual and sequential control methods are easy to implement and more stable and reliable in practice, but the tunnel interior luminance can be not adjusted along with the changes of weather, traffic volume and vehicle speed, the both methods hardly have any energy-saving effect, as a result, much electric energy is wasted [5]-[6]. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 116–123, 2011. © IFIP International Federation for Information Processing 2011
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Automatic control methods are widely used in modern tunnel lighting system, which can be divided into hierarchically control method and stepless control method according to adjustment continuity of tunnel light. At present, hierarchical control methods are often used in tunnel lighting control system in China before the application of LED lamps in tunnel lighting, but some problems exist in the methods, the main problems are: 1) the automatic control levels can be done are only from 2 to 3 because of the limited routing circuit, the parameters of environmental luminance, traffic volume and vehicle speed are only considered with maximum values at design stage, as a result, the lighting luminance of each section in tunnel is always in maximum state, lighting efficiency is evidently low, electric energy consumption is great; 2) the contradictions with driving safety and tunnel monitor arise during the operation course [7]-[8]. In the paper, an automatic control system for tunnel lighting is designed based on the characteristics of LED lamps, especially the characteristics of control easiness compared with other lamps, which made the luminance in tunnel be adjusted dynamically along with the changes of environmental luminance, traffic volume and vehicle speed, and thus continuous tuning of tunnel lighting is achieved. The control system not only ensures operation safety of the tunnel, but also realizes energy-saving.
2 Control System Structure In order to meet the demands of tunnel lighting and energy-saving better, stepless control method is adopted in the tunnel lighting control system. The control system is composed of vehicle detectors, luminance detectors, data converters, lighting control computer, dimming controllers and LED lamps. The structure block diagram is shown in Fig. 1. Environmental luminance, traffic volume and vehicle speed information are collected by vehicle detectors and luminance detectors. The data converted by data converters from collected information are sent to lighting control computer installed in tunnel control room. According to the predetermined dimming logic in lighting control computer, the luminance of each section in tunnel is calculated, the required
Vehicle detector
Data Converter Lighting Control Computer
Luminance detector
Data Converter
LED
LED
Dimming Controller
Dimming Controller
Data Converter
Fig. 1. Block diagram of tunnel lighting auto-control
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dimming values for dimming controllers of each node are calculated in the control computer in accordance with the preceding luminance calculated and power curve of LED lamps. The control computer sent control commands to dimming controllers, LED lamps power are adjusted by the commands received, and fed relevant information back to lighting control computer, and continuous light tuning of tunnel lighting is achieved.
3 Tunnel Lighting Control Strategy The control strategy of tunnel lighting system is designed based on “Specifications for Design of Ventilation and Lighting of Highway Tunnel” [9] (hereinafter referred to as the “Design Specifications”), the principle is that the mathematical models of each section in tunnel are established based on the adaptation curve of the luminance in tunnel (as shown in Fig. 2), tunnel exterior environmental luminance, traffic flow and vehicle speed information. In accordance with the established mathematical models, the dynamic dimming control of LED lamps is conducted, and the luminance in tunnel is very close to the adaptation curve, energy-saving is achieved with optimal control effect. Stepless control is not absolute continuous dimming, but a more refined hierarchical control method. Environmental parameters with maximum values are generally considered in hierarchical control at tunnel lighting design stage, the effect of the changes of environmental parameters is neglected. Sometimes automatic control is achieved whose control levels are only from 2 to 3 because of the limited routing circuit. Stepless control is closer to continuous dimming by adopting more refined levels [10]. When planning tunnel lighting, five sections have to be considered: access zone, entrance zone, transition zone, interior zone and exit zone. There are different lighting requirements for different zones. In order to meet requirements of human eyes adaptation to luminance, logarithm dimming method for LED lamps is adopted: single-lamp
/6 /$
adaptation curve
Luminance cd/m 2
/WK
/WU G
/WU /WU
6
$ Access zone
3
/LQ
(
P
Entrance zone Transition zone Interior zone
Fig. 2. Theory demand curve of tunnel lighting
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256-grade dimming, so that the whole tunnel lighting looks like a linear regulator dimming. Meanwhile, the threat of driving safety due to abrupt luminance change can be avoided by gradual control method. Triggering light dimming too often is not only conducive to the human eyes adaptability, and to some extent, service time of lamps is also reduced. Therefore time-triggered model is resorted during the control process: information of environmental luminance, traffic flow and vehicle speed is collected and required luminance is calculated at interval of 3~5 minutes. In this paper, the mathematical models of the luminance of each section in tunnel are established on the data from “Design Specification” by a linear regression. 1) The mathematical model of the entrance zone: one-rank linear regression is adopted in MATLAB to make statistics analysis of the data from “Design Specifications” and fitted regression equations of luminance discount coefficient of the entrance zone are obtained. The luminance discount coefficient of the entrance zone under different traffic volumes and vehicle speeds is calculated by formula (1).
⎧0.0004v − 0.0085 Q ≤ 700 ⎪ 0.54v + 0.0002Q(v − 1.1) − 12.91 ⎪ k=⎨ 1700 ⎪ ⎪⎩0.0006v − 0.0107 Q ≥ 2400
700 < Q < 2400 .
(1)
where v is vehicle speed, Q is traffic volume. The luminance of entrance zone is calculated by the formula (2).
Lth = k ⋅ L20 ( S ) .
(2)
where Lth is the entrance zone luminance (cd/m2); L20(S) is the tunnel exterior environmental luminance (cd/m2). The entrance zone luminance under different traffic volumes and vehicle speeds is calculated by formula (3). ⎧(0.0004v − 0.0085) × L20 ( S ) Q ≤ 700 ⎪ ⎪ 0.54v + 0.0002Q (v − 1.1) − 12.91 × L20 ( S ) Lth = ⎨ 1700 ⎪ ⎪⎩(0.0006v − 0.0107) × L20 ( S ) Q ≥ 2400
700 < Q < 2400 .
(3)
2) The mathematical model of the interior zone: the interior zone luminance is relevant to traffic volume and vehicle speed, the tunnel exterior environmental luminance has no effect on it. In order to reduce the luminance calculation error, the second-order linear regression is adopted to fit the interior zone luminance values. The interior zone luminance under different traffic volumes and vehicle speeds is calculated by formula (4). ⎧0.0013v 2 − 0.135v + 4.95 Q ≤ 700 ⎪ 2 2 ⎪158v + 0.09v Q − 19534v − 4.88vQ + 4.75Q + 808250 Lin = ⎨ 700 < Q < 2400 . 170000 ⎪ ⎪0.0022v 2 − 0.1838v + 5.425 Q ≥ 2400 ⎩
(4)
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3) The transition zone luminance depends on the entrance luminance. The transition zone is composed of three sections: Ltr1, Ltr2, Ltr3, and the corresponding luminance of each section is calculated by Ltr1=0.3Lth, Ltr2=0.1Lth, Ltr3=0.035Lth, respectively, according to the “Design Specifications”. 4) The exit luminance is 5 times of the interior zone luminance, Lout=5Lin.
4 Main Control Program Flow Chart The flow chart of the main tunnel lighting control program is shown in Fig. 3, the steps are: (1) Initializing sub-modules of the system, reading luminance information
Begin
Initialize Modules
Read Data
Manual Control Enable˛
<(6
12 Tunnel Status is Normal˛ Interval from 3-5min
<(6 Auto-dimming Control Program
(QG 12
Call Special Program
Alarm Control Instructions End Feedback Information
12
Stop Program˛ <(6 End
Fig. 3. Flow chart of tunnel lighting control system
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and vehicle information, and judging whether the manual control is enabled (the automatic control is implemented by default). (2) If the automatic control is implemented, judging whether the tunnel is in normal state, if in abnormal state, calling the special control procedures, alarming and ending the program; if in normal state, calling control procedures of automatic dimming directly and outputting control instructions, so one dimming course is completed. (3) Judging whether the program is stopped by instruction of external trigger, if not, collecting the new data at interval of 3~5 minutes, if yes, ending the program. The mathematical model and control flow are converted into the corresponding control program and embedded in the lighting control computer to realize automatic dimming control of tunnel lighting.
5 Simulation According to the mathematical model and control method, combining with the environmental data, a simulation experiment and analysis is done. Setting parameter values of environmental luminance, traffic volume and vehicle speed in different time range during sunny day, 20 sets of simulation luminance data of each section in tunnel are collected, part data are shown in Table 1 (only 5 sets of sample data are listed in the paper). The theoretical luminance data of each section in tunnel are calculated according to the established mathematical model and environmental parameters set, 5 sets of data are shown in Table 2. Comparing the data of Table 1 and Table 2, the simulation luminance data are very close to the theoretical luminance data, the error range can be controlled at 2%, even less. The power curves of tunnel lighting in sunny day are shown in Fig. 4, it can be seen from the graph that 40%~50% energy-saving is achieved by using LED lamps to replace HPS lamps. Energy-saving effect of stepless control to LED lamps is very obvious, compared with HPS lamps and LED lamps only considering maximum lighting value, the energy-saving is more than 80% and 35% respectively. Even compared with 4-steps controlled LED lamps, stepless controlled LED lamps can save more than 20 % energy.
Table 1. Simulation luminance data (partly) Exterior luminance (cd/m2) 4000 4000 3000 3000 2000 2000
Traffic volume (vehicles/h) 500 1000 1500 2500 1500 1000
Vehicle speed (km/h) 65 75 85 95 85 75
Lth
Ltr1
Ltr2
Ltr3
Lin
Lout
73 99 96 142 67 51
21.9 29.7 28.8 42.6 20.1 15.3
7.3 9.9 9.6 14.2 6.7 5.1
2.6 3.5 3.4 5.0 2.3 1.8
1.8 2.4 3.6 7.9 4.1 2.3
9.0 12.0 18.0 39.5 20.5 11.5
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Exterior luminance (cd/m2) 4000 4000 3000 3000 2000 2000
Traffic volume (vehicles/h) 500 1000 1500 2500 1500 1000
Vehicle speed (km/h) 65 75 85 95 85 75
Lth
Ltr1
Ltr2
Ltr3
Lin
Lout
70 95 97 139 65 48
21 28.5 29.1 41.7 19.5 14.4
7 9.5 9.7 13.9 6.5 4.8
2.5 3.3 3.4 4.9 2.3 1.7
1.7 2.2 3.8 7.8 3.8 2.2
8.5 11 19 39 19 11
3RZHU5DWLR 3RZHU&XUYHRI+36
3RZHU&XUYHRI 5DWLQJ'LPPLQJ
3RZHU&XUYHRI/('
3RZHU&XUYHRI 6WHSOHVVGLPPLQJ
WK
Fig. 4. Power curves of tunnel lighting in sunny day
6 Conclusion Tunnel lighting is an important component of highway traffic; its primary function is to ensure driving safety and comfort during both daytime and nighttime in tunnel. However, energy-saving is also great of importance and cannot be neglected. In this paper, an automatic control system of tunnel lighting is designed based on superior performance of LED lamps and stepless control. The designed control system can meet the lighting requirements very well and overcome the problem of large electricity waste caused by traditional lighting control methods. The impact of the changes of environmental luminance, traffic flow and vehicle speed is considered, continuous dimming of tunnel lighting is achieved, and energy-saving effect is remarkable.
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Acknowledgements. This work is supported by Key Laboratory of Ministry of Education for Conveyance and Equipment (East China Jiaotong University).
References 1. Schreuder, D.A.: Road Lighting for Safety. Thomas Telford Publishing, London (1998) 2. Commission Internationale de L’Eclairage: CIE No88-2 Guide for the Lighting of Road Tunnels and Underpasses. CIE Publication, Vienna (1999) 3. Illuminating Engineering Society of North America: ANSI/IESNA RP-22-96 American National Standard Practice for Tunnel Lighting. American National Standards Institute, Washington(1996) 4. British Technical Committee: BS 5489-2 Code of practice for the design of road lighting Lighting of tunnels. British Standards Institution, London (2003) 5. Huang, T.S., Luo, F.: Energy saving tunnel lighting system based on PLC. In: 2006 China International Conference on Electricity Distribution (CICED 2006), Beijing, China, pp. 527–533 (2006) (in Chinese) 6. Nagai, S., Ishida, S., Shinji, M., Nakagawa, K.: Energy-saving lighting system for road tunnel. In: Underground Space Use: Analysis of the Past and Lessons for the Future, Istanbul, Turkey, pp. 625–631 (2005) 7. Li, R., Fu, D., Chen, Z.Y.: Energy-saving & Control of Tunnel Illumination. Highway Engineering 32(5), 204–206 (2007) (in Chinese) 8. Zhi, H.: Research on illumination energy saving technique of highway tunnel. In: China International Conference on Operation Management and Safety of highway Tunnel, Chongqin, China, pp. 343–347 (2006) (in Chinese) 9. Ministry of Communications Highway Scientific Research Institute: JTJ 026.101999 Specifications for Design of Ventilation and Lighting of Highway Tunnel. China Communications Press, Beijing (2000) 10. Lv, X.F.: The Application of Stepless Intelligent Control System to LED Illuminating Brightness in Tunnel. China Lighting (10), 96–98 (2008) (in Chinese)
Comparative Study of Distance Discriminant Analysis and Bp Neural Network for Identification of Rapeseed Cultivars Using Visible/Near Infrared Spectra Qiang Zou, Hui Fang, Fei Liu, Wenwen Kong, and Yong He College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310029, China [email protected]
Abstract. The potential of visible/near infrared spectra as a method of nondestructive discrimination of various rapeseed cultivars was evaluated, discrimination ability of distance discriminant analysis (DDA) and BP neural network (BPNN) for identification of rapeseed cultivars was shown in this article. The spectral curves ranging from 350 to 2500 nm of rapeseed cultivars were obtained by VIS/NIR spectroscopy, and the principal component analysis (PCA) was applied to perform the clustering analysis. The first 6 principle components (PCs) extracted by PCA were employed as the inputs of DDA and BPNN, respectively, and then two different discrimination models for rapeseed cultivars were built. Forty-five samples from each species and a total of 225 samples from 5 categories rapeseed were extracted. One hundred fifty samples were elected randomly as training sets to set up the training model which was validated by the samples of prediction sets formed by the remaining 75 samples. The result error of BPNN model was set to be ±0.15, and the result indicated that no samples exceeded threshold value, therefore the distinguishing rate was 100%. The result of DDA model displayed that the recognition rate of 100% was achieved. Although the methods mentioned in the presented paper were good approaches for nondestructive discrimination of rapeseed cultivars, DDA model with prediction functions was more intuitive than BPNN and convenient to machine recognition. Keywords: comparative study, BP neural network, distance discriminant analysis, visible/near infrared spectra, rapeseed cultivars.
1 Introduction Oilseed rape, being one kind of major oil crops and nectar plants in China, is herbaceous cruciferous crops and is expanding rapidly as a rotation crop following rice [1]. In 2000, rapeseed was the third leading source of vegetable oil in the world, after soy and palm and is the world's second leading source of protein meal. Oil content of oilseed rape depends on rapeseed cultivars greatly, so discrimination of rapeseed cultivars is a very important part of detection for oilseed rape's quality. Randomly Amplified Polymorphic DNAs (RAPDs) were used to discriminate among 23 cultivars of oilseed rape (Brassica napus) in 1994 [2]. In 2007, Principles and advantages of particular D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 124–133, 2011. © IFIP International Federation for Information Processing 2011
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marker techniques and application of molecular markers in rapeseed cultivar identification were discussed by Curn V [3]. Because of operational complexity and difficulty for RAPDs and molecular markers, it is very inconvenient to use it. Thus, it is interested in the possibility of on-line non-destructive sorting process for identification of rapeseed cultivars. Nowadays, visible and near infrared (Vis/NIR) spectroscopy is widely employed as a method for measurement of quality in many fields, such as agriculture, pharmaceuticals, food, textiles, cosmetics, and polymer production industry [4]. Some reports are available on use of visible and near infrared (VIS/NIR) spectroscopy for identification of cultivar [5, 6]. Study of rapeseed using visible and infrared spectroscopy has been reported [7, 8, 9, 10]. However, these papers are just related to physical and chemical analysis, such as oil content, sinapic acid esters assessment. The performance of a classification or discrimination depends on the separability of the classes. This suggests that the centres of clusters within the measurement space should be sufficiently separated [11]. However, study of identification with linear identification model have shown that linear discriminator do not often yield satisfactory performances [12]. Thus, comparsion of non-linear model such as BP neural network (BPNN) and linear model such as distance discriminant analysis (DDA) for discrimination of rapeseed cultivar was studied. BPNN, one kind of neural network widely used by researchers, consisting of three elements including input layer, hide layer and output layer, are computationally robust with having the ability to learn and generalize from examples to produce meaningful solutions to problems even when the input data contain errors or are incomplete [13]. DDA, which can indentify samples species on the basis of distance between the samples and training set, is a supervised learning technique of statistical pattern recognition. The same as other math models, the critical step of establishing both analysis methods is to get appropriate input variables. Because of large amounts of data, raw spectra data can not to be as inputs of model directly. And excessive input spectra data can result in lager number of iterative training [14], also it leads to the over-regression between the prediction and the training samples [15]. Principal component analysis (PCA) provides a good solution dealing with these problems for us. The objective of this study was to investigate the potential utilization of VIS/NIR spectroscopy combined with chemometric or statistical methods to discriminat the rapeseed culvers with different attributes. PCA was used to extract principal components (PCs) from a large number of spectra data. Then, BPNN and DDA model were established, respectively. And the quality of two discriminant model was assessed in this paper.
2 Material and Methods 2.1 Instrument and System Set-Up In this research, the ASD FieldSpe Pro FRTM Spectrometer from ASD (Analytical Spectral Device) was applied. This spectrograph has high sensitivity range from 350 to 2500 nm. The interval of sampling is 1.4 nm and the sensitivity is 3.5 nm range from
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350 to 1000nm. From 1000 to 2500 nm, the interval of sampling is 2nm. The software of ASD View Spec Pro, Unscramble V9.6 (CAMO, PROCESS, AS, OSLO, Norway), DPS (data procession system for practical statistics) and SAS (Statistical Analysis System) were used in this study. 2.2 Samples and Measurements In this study, a total of 225 samples of five kinds of rapeseed, as showed in Table 1, were from farm of Zhejiang University, Hangzhou (30010'N, 120012'E). In order to reduce the error of operation and Environmental differences, the uniform petri dish (diamitor: d = 65 mm, height: h = 1.4 mm) was chosen to bloom rapeseed which covered the bottom of petri dish. 2.3 Pretreatment of Original Spectral Data The pretreatment methods, such as multiplicative scatter correction (MSC), SavitzkyGolay (SG) smoothing, Standard normal variate (SNV) and so on, usually are used to reduce the error which contains in original spectral data. Chu, Yuan and Lu [16] used the smoothing method of Savitzky Golay (SG) with segment size 3 and default polynomial order zero to decrease the noise. It had been proved that many high frequency could be eliminated [17]. The standard normal variate (SNV) was used to used to remove the multiplicative interferences of scatter, the change of light distance, and particle size [18]. Both pretreatment methods were used in this study. The pre-process and calculations were carried out using a statistical software package named Unscrambler V9.6 for multivariate calibration. To avoid the low signal-noise ratio, the first 100 wavelength values and the last 200 wavelength values were removed, only the wavelength ranging from 450 to 2300 nm was used in this investigation [19, 20]. Table 1. The varieties of the sample in the research Varieties
Class
From
Number of samples
Qingza2(QZ2)
Qing Za
Zhejiang University
45
Qingza3(QZ3)
Qing Za
Zhejiang University
45
Qingza5(QZ5)
Qing Za
Zhejiang University
45
Qingyou14(QY14)
Qing You
Zhejiang University
45
Qingyou241(QY241)
Qing You
Zhejiang University
45
2.4 Method Two kinds of methods for clustering, visualization of VIS/NIR spectra and classification the different varieties rapeseed, by PCA, BPNN and DDA model, were showed and compared with each other. The features of spectra data after pretreatment were visualized by principal component analysis in PCs space, then the PCs closely
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correlative with the categories of these samples, were used as the inputs of an BPNN model and DDA model, respectively, for classification of rapeseed cultivars.
3 Results and Discussion 3.1 The Reflectance Spectra Data of Rapeseed Cultivars All the achieved spectra data were averaged, and changed to the ASCII code, which was used for building the reflectivity matrix for later use. Fig.1 shows the typical curves of the reflectance spectra of each variety of rapeseed. The trend of all spectra curves was similar, but the differences of wavelength values ranging 450mm from 1000mm among the different rapeseed cultivars were existed after comparing in detail. The mainly reason might be differences in apparent color of different rapeseed cultivars in visible spectrum. At the same time, it can be found that there was not remarkable difference in the other spectral range, some tiny difference can be detected, which make it possible to discriminate the different varieties. 3.2 Data Visualization by PCA The spectra data matrix after pretreatment contained 1851×225 numbers, it was difficult to use it as input of model. Thus, PCA was used to extract PCs to enhance the features of spectra data and reduce dimensionality of matrix. 20 PCs were extracted from 225 spectra curves of rapeseed. Table 2 listed the accumulative reliabilities of PC1, PC2, PC3, …, PC10. It could be found that the accumulative reliabilities of the first 6 principal components was 99.817% and the rest of accumulative reliabilities just was 0.183%. It meant that, 6 PCs contained all the informations of variables, to some extent. Thus, 6 principal components could provide good discrimination of varieties. 0.8 0.7
Reflectance
0.6 0.5 0.4 0.3 0.2 0.1 0 350
850
1350 1850 Wavelength/nm
2350
Fig. 1. VIS/NIR reflectance spectra of five varieties of rapeseed
2850
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Table 2. PCs and accumulative reliabilities PC Ar(%)
PC1
PC2
PC3
PC4
PC5
PC6
PC7
PC8
PC9
PC10
91.213
97.224
98.905
99.658
99.758
99.817
99.838
99.854
99.865
99.871
PC: Principal components; Ar: accumulative reliabilities.
The PCA scores graph shown in Fig.2, which was organized according to the number of the rapeseed, was built using PC1 with PC2. It was easy to draw that the rapeseed was closely clustered and the differences among most kinds of rapeseed were displayed except the QZ3 and QZ5, which were mixed with each other. QZ varieties and QY varieties were separated by CP2-axis. The reason could be that the differences of their variety characteristics were apparent. Although the principal component analysis can qualitatively distinguish between different varieties of rapeseed, but could not give a quantitative identification model.
Fig. 2. Scatter plot (PC1 ×PC2) of 225 rapeseed samples
3.3 Classification by BPNN Model One hundred fifty samples from 225 samples were elected randomly as training sets to set up the training model which was validated by the samples of prediction sets formed by the remaining 75 samples. The first six PCs, which can explain the 99.817% of variables, were elected as inputs to build BP neural network model. The numbers from 1 to 5 stood for varieties of five kinds of rapeseed. So, the output value 1 was QZ2 rapeseed, 2 stood for QZ3 rapeseed, 3 was denoted as QZ5 rapeseed, QY14 rapeseed was stood for by 4 and 5 was denote as QY241 rapeseed. With errors comparison, the best 3-layer neural network structure was determined to build BPNN model after adjusting by many times [21, 22, 23]. The optimal nodes of the hidden layer of neural network were 8 and the maximum number of iterations was 2000. The parameter of sigmoid and the least training speed were set as default
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values of 0.9 and 0.1, respectively. The residual error was set as 0.00001. The threshold value of prediction error was ±0.15. If error exceeded the threshold, the prediction result was wrong. The prediction error of each sample was shown in Fig.3 for the training set and prediction set. The result showed that the errors were close to 0. Identification result for training set and the prediction set was shown in Table 3, and the recognition ratio of 100% was achieved.
Fig. 3. The result error value of prediction results of training set and prediction set by BPNN model Table 3. Classification and prediction rate of BPNN model Classification Class QZ2 QZ3 QZ5 QY14 QY241 Total
Prediction
NO.
False NO.
Accuracy rate(%)
30
0
100
15
0
100
30 30
0 0
100 100
15 15
0 0
100 100
30
0
100
15
0
100
30 150
0 0
100 100
15 75
0 0
100 100
NO.
False NO.
Accuracy rate(%)
3.4 Clustering with DDA Model DDA, a linear discriminant method, is a multivariate technique, which can allocate new objects to populations previously defined threshold error of recognition and separate objects from distinct populations [24]. In this study, there were five varieties of rapeseed that were classified through distance discriminant analysis. PCs, inputs of BP neural network model, were used as inputs of DDA model. SAS statistical software was used to calculate the spectra data. The discriminant functions of DDA model achieved by SAS were listed in Table 4.
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Table 4. Discriminant functions of DDA model Varieties QZ2 QZ3 QZ5 QY14 QY241
Functions Y1(x)=-201.44725-66.17473PC1+204.59991PC2-5.21388PC3+264.62153PC4 -109.86786PC5+314.48234PC6 Y2(x)=-290.19263-59.33282PC1+413.00733PC2-685.86068PC3+412.97573PC4 +71.88543PC5+257.70740PC6 Y3(x)=-119.06113+0.61504PC1-154.57826PC2-1.45941PC3-362.24558PC4 +737.24938PC5-76.96774PC6 Y4(x)=-267.17728-8.88928PC1+422.19211PC2-491.43925PC3+285.38541PC4 +93.56473PC5+427.92977PC6 Y5(x)=-918.38635+135.18458PC1-868.94013PC2+1112PC3-607.09393PC4 -59.34903PC5-931.26578PC6
The more information applied by functions. The greater the absolute value of coefficients was, the greater the contribution of this variable on the function was, and vice versa. For example, the absolute value of PC6 was maximum and the absolute value of PC3 was minimum in discriminant function for QZ2, so variable PC6 make the greatest contribution for function and PC3’s was the smallest. Table 5. Classification and prediction rate of DDA model
Class QZ2 QZ3 QZ5 QY14 QY241 Total
NO. 30 30 30 30 30 150
Classification False PP(%) NO. 0 0 0 0 0 0
100 100 100 100 100 —
Accuracy rate(%)
NO.
100 100 100 100 100 100
15 15 15 15 15 75
Prediction False PP(%) NO. 0 0 0 0 0 0
100 100 100 100 100 —
Accuracy rate(%) 100 100 100 100 100 100
PP: posterior probabilities.
The rule for discriminating the varieties of prediction samples is that: the probability for a sample with G possible varieties belonging to each category is pi (i = 1, 2,…, G). Assume that pS is maximum among pi (i = 1, 2,…, G), it means pS = max{p1, p2, …, pG}, ( 1•S•G). S•G). And then, it is concluded that this sample belongs to S variety. In this work, the posterior probability of prediction samples was calculated. Each sample was classified accurately and their posterior probabilities for correct cultivars were 1.00. The accuracy rate was 100% and result was displayed in Table 5. Thus, the stepwise discriminant analysis model was realistic, correct and valuable. 3.5 Methods Comparison There were two methods for discrimination of rapeseed cultivars using VIS/NIR spectroscopy, BPNN and DDA. Two methods are ordinary used in many fields, such
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as food, chemical industry, and so forth. BPNN could be used for prediction the content of a component of a substance, while DDA is generally applied for identification of category of unknown samples based on samples with known types. 225 samples from 5 rapeseed categories were analyzed for comparison of two analysis methods. Because of generalization ability and fault tolerance of BPNN model, a very few error data for samples has little effect on rules between inputs and outputs. But BPNN model for identification of rapeseed cultivars wasted a plenty of training time, this is its shortcoming. For obtaining the rules of inputs and outputs we wish, model parameters, such as residual error, least training speed and maximum number of iterations must be adjusted repeatedly, whereas for DDA model PCs can be finished using SAS statistical software without adjusting time. Although the recognition ratios of 100% for two methods were acquired, the result of DDA model with SAS was more credible. Recognition ratio of BPNN model depended largely on the threshold of error of prediction value. In this study, the threshold was set to be ±0.15, so recognition ratio of 100% was achieved. If the threshold was set to be ±0.1, the recognition ratio maybe reduces. The reliability of recognition rate without giving authentication probability using BPNN model should be analyzed again. While posterior probabilities, 1.00 for all samples including training set and prediction set, were got by discriminant analysis using SAS and it meant that its recognition ratio’s reliability was good. Finally, although the methods mentioned in this study were good approaches for non-destructive identification of rapeseed cultivars, DDA with prediction functions was more intuitive than BPNN and more convenient to machine recognition.
4 Conclusion A rapid and non-destructive approach for identification of rapeseed cultivars was presented. And rapeseed with different varieties was classified by two methods, chemometrics and statistical methods, using VIS/NIR spectroscopy. In this study, quantitative analysis for the varieties of rapeseed was made, by combining with SG smoothing, SNV, PCA, BPNN and DDA, relative between reflectance spectra and rapeseed cultivars was built. The BPNN and DDA model displayed an excellent data prediction performance, and the recognition rate of 100% was achieved using two methods. BPNN model should be adjusted repeatedly, compared with DDA, it was not convenient to analyze the spectra data for identification. So DDA was a better method for discrimination of varieties and discriminant analysis with prediction functions was more intuitive than BPNN for identification of rapeseed cultivars.
Acknowledgements Funding for this research was provided by Science and Technology Department of Zhejiang Province (Project No. 2009C12002), National Natural Science Foundation (Project No. 60802038), National High Technology Research and Development Program of China (863 Program, Project No. 2006AA10Z234).
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References 1. Fei, L., Fan, Z., Zonglai, J., et al.: Determination of acetolactate synthase activity and protein content of oilseed rape (Brassica napus L.) leaves using visible/near-infrared spectroscopy. Analytica Chimica Acta. 629(1,2), 56–65 (2008) 2. Mailer, R.J., Scarth, R., Fristensky, B.: Discrimination among cultivars of rapeseed (brassica-napus L.) using DNA polymorphisms amplified from arbitrary primers. Theoretical and Applied Genetics 87(6), 697–704 (1994) 3. Curn, V., Zaludova, J.: Fingerprinting of Oilseed Rape Cultivars. Advances in Botanical Research: Incorporating Advances in Plant Pathology 45, 155–179 (2007) 4. Yan, Y.L., Zhao, L.L., Han, D.H., et al.: The Foundation and Application of Near Infrared Spectroscopy Analysis. China Light Industry Press, Beijing (2005) 5. He, Y., Li, X.L., Shao, Y.N.: Discrimination of varieties of apple using near infrared spectra based on principal component analysis and artificial neural network model. Spectroscopy and Spectral Analysis 26(5), 850–853 (2006) 6. Romdhane, K., Éric, D., Laurent, P., et al.: The potential of combined infrared and fluorescence spectroscopies as a method of determination of the geographic origin of Emmental cheeses. International Dairy Journal 15(3), 287–298 (2005) 7. Huang, M., He, Y., Cen, H.Y., et al.: Rapeseed nitrogen status estimation of Vis-NIR spectra based on partial least square and BP neural network. In: 2007 IEEE International Conference on Control and Automation, vol. (1-7), pp. 2387–2391 (2007) 8. Gan, L., Sun, X.L., Jin, L., et al.: Establishment of math models of NIRS analysis for oil and protein contents in seed of Brassica napus. Scientia Agricultura Sinica 36(12), 1609–1613 (2003) 9. Ding, X.X., Li, P.W., Li, G.M., et al.: Analysis of erucic acid and glucosinolate in intact rapeseed by fourier transform near infrared diffuse reflectance spectroscopy. Chinese journal of oil crop sciences 26(3), 76–79 (2004) 10. Velasco, L., Matthaus, B., Mollers, C.: Nondestructive assessment of sinapic acid esters in Brassica species: I. Analysis by near infrared reflectance spectroscopy. Crop Science 38(6), 1645–1650 (1998) 11. Younes, C., Dominique, B., Yvette, D., et al.: Identification of Seeds by Colour Imaging: Comparison of Discriminant Analysis and Artificial Neural Network. Journal of the science of food and agriculture 71(4), 433–441 (1996) 12. Kim, J., Mowat, A., Poole, P.: Linear and non-linear pattern recognition models for classification of fruit from visible-near infrared spectra. Chemometrics and Intelligent Laboratory Systems 51(2), 201–216 (2000) 13. Nasseri, M., Asghari, K., Abedini, M.J.: Optimized scenario for rainfall forecasting using genetic algorithm coupled with artificial neural network. Expert Systems with Applications 35(3), 1415–1421 (2008) 14. Tang, Y.F., Zhang, Z.Y., Fan, G.Q., Zhu, H.J., et al.: Identification of official rhubarb samples based on IR spectra and neural networks. Spectroscopy and spectral analysis 25(5), 715–718 (2005) 15. Shao, Y.N., He, Y., Wang, Y.Y.: A new approach to discriminate varieties of tobacco using vis/near infrared spectra. Eur. Food Res. Technol. 224(5), 591–596 (2007) 16. Chu, X.L., Yuan, et al.: Progress and application of spectral data pretreatment and wavelength selection methods in NIR analytical technique. Progress in Chemistry 16(4), 528–542 (2004)
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Current Situation and Prospect of Grassland Management Decision Support Systems in China Qingwei Duan, Xiaoping Xin*, Guixia Yang, Baorui Chen, Hongbin Zhang, Yuchun Yan, Xu Wang, Baohui Zhang, and Gang Li 1
Hulunber GrassLand Ecosystem Observation and Research Station, Beijing 100081, P.R. China 2 Key Laboratory of Resource Remote Sensing and Digital Agriculture, Ministry of Agriculture, Beijing 100081, P.R. China 3 Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China [email protected], [email protected]
Abstract. China, with wide grassland areas of the second rank throughout the world, is faced with a severe challenge on how to manage its vast and degenerating/degenerated grassland. Computer and network technologies are more and more widely applied in grassland production, research and education, which is just a greatly encouraging field. Tremendous achievements have been made in grassland management decision support system (GMDSS) research in developed countries at present, but there is still a long way to obtain a great development for developing countries, such as China. This paper reviewed the research progress and current situation in the GMDSS research and application in China. Concept models and empirical models are still hugely focused on the corresponding research fields in China, but the integrated GMDSS has not been well developed. Therefore, Chinese scientists must develop the integrated models from the existing models, and accordingly sinicize the GMDSS of models used in the developed countries for availably application. In the other hand, there is a same direction of research and development about the GMDSS not only for developed countries but also for China, which is going to be combined with internet, 3S (GIS, RS and GPS) and virtual technology.
1 Introduction Information technology, digital agricultural technology and decision support systems (DSS) and other technologies have been put on a very important position in agriculture, but China is still relatively lagging behind in the field of grassland management DSS(GMDSS) especially when compared with the devoloped countries.In this serious international situation, we must catch up, otherwise we will not only lag behind in scientific research, but also prevents China to an inferior position in the international competition in the livestock industry. *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 134–146, 2011. © IFIP International Federation for Information Processing 2011
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The grazing system is a complex systems, including animals, plants, environment and peoples. About pasture growth, animal nutrition, the environment changes and the management of human behavior factors on grazing system interaction, a great deal of statistics models, mechanism models and simulation models have been set up in the past. Scientists established many computer DSS with the existing models, which improved the grassland management from a extensive management to a targeted intensive management. By simulating various production management strategy with the DSS, the simulation results can guide the production and management. Judging from the production level of GMDSS, it reducing the production management of blindness, reduce business risks; from the policy level, it helping the decision support for the government. With scientific and technological development and social needs increasing, grazing management simulation model have been made remarkable achievements in research and applications (Duan Qingwei, 2009). This paper reviews the recent studies of domestic progress about GMDSS, including the base model, small DSS, network technology, remote sensing, GIS technology, WebGIS technology and virtual reality technology in DSS applications, and highlighted several ongoing large-scale domestic DSS research, and to outlook China's future trends in DSS research for reference of China GMDSS research and applications.
2 Construction of Basic Model 2.1 Crop Growth Models Crop growth models can be used in pasture systems, hence the crop growth model would greatly facilitate pasture models study. Although the crop growth simulation research started very late, some basic researchs have been undertaken in China.Such as, “Rice population computer simulation model of material production” from Shanghai Institute of Plant Physiology of the CAS. “Rice growth calendar model (RICAM)” from Jiangxi Agricultural University; After 1990s, Institute of Agricultural Meteorology, Chinese Academy of Agricultural Sciences, finished CERES - Maize model Chinesization. In 1992, Jiangsu Academy of Agricultural Sciences finished “Rice cultivation Computer Simulation Optimization Decision System (RCSODS); Chinese Academy of Agricultural Sciences finished “Cotton Production Management Simulation System” (Zhang Wei, et al.). Liu Yilian, Chou Ziming (1994a) established populations of Leymus chinensis meadow Hulunbeier growth and yield simulation model based on the theory of crop growth simulation, combined with the growth characteristics of natural grass. The model consists of three sub-models: (1) photosynthesis and respiration; (2) assimilate distribution; (3) leaf area. The model can simulate aboveground biomass of Leymus chinensis populations with temporal dynamics by using the measured data validation of the model, and more objectively reflect the weather conditions on the grass growth and yield formation. Liu Yilian, Chou Ziming (1994b) carried on a certain numerical experimentation using the kinetic simulator model of Leymus chinensis.They discussed the influence of the meteorological factor-temperature, soil moisture, solar radiation not in the same year to change—to Leymus chinensis population output; The output calculates the dynamic
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“actual production”, Which shows the statistical model simulation potential and the limitation. Pu erciren, Liu Naizhuang(1994) took the crops growth analog theory as a foundation, considered the multi-populations character of the steppe community, established the population biomass time dynamic synthesis influence's whole pattern for the high and cold Kobresia humilis meadow ,Which can reflect effect of the meteorological factor and the biotic factor to biomass production, including random population physiological process-photosynthesis, respiration, assimilation products assignment- quantity simulations and the leaf area index dynamics, the community structure kinetic simulator et.al, 6 kinds of subschemata,which can quantify the grassland community ground biomass and the underground biomass seasonal variation, and that is a good attempt of prairie vegetation photosynthesis output simulator study. Wei Yurong (2004) used the Xilingol typical grassland animal husbandry meteorology data, from the environment factor to the forage and domestic animal influence's angle embarking, from qualitative to the quantitative analysis external environment condition to the grassland animal husbandry production's influence and the revelation lawn animal husbandry production rule, established a set decision-making service system to be possible to used in instructing the animal husbandry production. 2.2 Remote Sensing Model Grassland Production A large number of grassland productivity models for livestock balance in China have also been established. Most of these models are fitted empirical models, which fitted between vegetation indices (such as NDVI, EVI et.al) obtained through remote sensing technology and ground biomass data. Huang Jingfeng et.al (2000) established spectrum of natural pasture vegetation index and satellite remote sensing monitoring model, meteorological monitoring model, using spectral observations of natural pasture, forage production data, meteorological data and NOAA /AVHRR data, which can provide a timely and accurate scientific means to grasp the grassland production change.Xiong (2004) estimated global primary productivity (NPP)by using Application of Advanced Earth Observing Satellite II (Advanced Earth Observing satellite II, ADEOSII) of the global multi-spectral data. And he also produced a ground-NPP algorithm with temperate plants in Japan.Based on the algorithm, he estimated NPP pattern based on Mongolian Plateau decomposition vegetation index(VIPD). Liu Aihua, Xing Qi(2003) established a model with vegetation index and ground-based data using MODIS images, and monitored productivity of natural grasslands in Inner Mongolia.They estimated the natural grassland carrying capacity in the warm and cold season for the administrative departments at all levels grassland and livestock production based on macro-management decision-making. Li Bo, Shi Peijun, et.al. (1995) studied the principles and methods of grazing livestock balance dynamic monitoring system in the temperate grassland, designed the dynamic monitoring database,technology systems and remote sensing production dynamic monitoring model in order to establish wide range of dynamic monitoring system of grassland resources, and provide a basis for the grassland management decisions. Liu Xingyuan et.al (2010) established remote sensing monitoring model between the grass amount of biomass and edible forage in Gannan from 2005 to 2007 using daily MODIS surface reflectance product MOD09GA and
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fresh weight of aboveground biomass of the measured data and the actual stocking rate.and estabished a different season grazing pasture livestock balance of theoretical stocking rate models and monitoring model to analyze the productivity of natural grass and stocking density in space-time dynamic balance condition and regulation strategies. 2.3 The Model Construction and Application of Mathematical Methods in Grassland Management System dynamics theory, gray relational grade analysis theory and gray forecast technique have some applications in grassland management. Shan Baoyan, Xu Jianhua (1995) established the grassland ecological economic system optimal model of sustainable development, including pasture management and herd optimal control model of management optimization model,with which to explore the improvement of the capacity expansion of the system environment strategy.Yan Wenbin and Wang Xuemeng establish the dynamic model with the accumulated data of his grass-rabbit system.They put forward the optimization of artificial grassland ecosystem control strategy by using the gray system approach (Xu Jianhua, 2006). 2.4 Systems Dynamics Simulation of the Grassland Management System dynamics is a discipline about the analysis of information feedback system, and also an integrated cross-discipline which to be used to understand system problems and resolve system problems.It is an integrated natural and social sciences disciplines based on systems theory,control theory, information theory,. Lv Shengli use system dynamics to simulate grassland ecosystem very early 1990s in China. Lv Shengli, in Gansu Academy of Sciences, built a set of models in second production in micro and macro aspects of grassland.LvShengli (1991) studied“China grassland productivity simulation”. He simulated the productivity of grassland for macro-and long-term dynamics by using system dynamics approach, system dynamics modeling and computer simulation tools. And he also made a scientific prediction and verification for the grassland productivity and the development trend of China. Outstanding features of this study compared with similar studies abroad are: 1), According to existing problems of grazing management in China, highlighting the breed of livestocks and livestock structure adjustment; 2), Focus on solving the contradiction between supply and demand cool-season forage, so that Grasssland Seasonal Livestock Manegement theory can reach the stage of dynamic simulation; 3), Suitable for medium and long term macro-policy research. Lv Xiaoying, LvShengli (2003) established a dynamic model of grassland animal husbandry sustainable development using principles and methods of System Dynamics.This study simulated the livestock husbandry prospects for the future development on the 2000-2020 period in the northern temperate zone and alpine grassland steppe grassland.Dynamic model of sustainable agriculture development takes cold season and warm season forage needs satisfaction rate as bonds, which make primary pasture production and secondary livestock production process a organic whole coupled with the dynamic and complex feedback structure. With this model we
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can achieved analysis and comparison of a variety of sustainable agriculture development simulation programs, from which to reveal the barriers in the development process, seek strategies to improve the status of a favorable way, show various scenarios of possible development trends, provide a basis for policy-makers. Aim at Gannan grassland animal husbandry practical situation, one of the major pastoral areas in Gansu Province, Duan Shunshan, Lv Shengli et.al (1995) analyzed the Gannan grassland animal husbandry development of power and constraints; predicted 30 years of pastoral animal husbandry in Gannan (1990-2020) the dynamic process of development and change; established long-term development of grassland animal husbandry in Gannan dynamic model by using system dynamics simulation technology, system dynamics flow diagram and spreadsheet functions.
3 Construction of GMDSS 3.1 Grass-Livestock Digital Management DSS in Pastoral Area Lanzhou University preside over “the pastoral area grass livestock digitization to manage DSS” the topic (2007AA10Z232) from the People's Republic of China Department of Technical Science, Which was authorized in 2007. It is a special topic--modern agriculture area of technology digit agricultural technology-in the project the national high-tech research development plan (863 plans).This beginning and end age limit of the topic is August, 2007 to October, 2010, Beijing Raising livestock Research institute of Chinese Agriculture Academy of science is the cooperation unit. This topic sets an experiment area of the Gannan pastoral area, through the investigation and the monitoring to the grassland and the livestock husbandry, with the help of network techonology, 3S technology, system model and optimized decision-making, the exploration research based on MODIS. (Moderate Resolution Imaging Spectradiometer) grassland remote sensing monitoring and the evaluating indicator system, they established the grassland information fast gain model, the grass livestock dynamical equilibrium and the analysis diagnostic model and the pastoral area grassland animal husbandry integrated management decision model.They made a contrastive analysis for lately 30 year grass livestock spatial variation condition, optimized grass livestock production technology flow, constructed GMDSS based on the network technology. This project already applied for the pastoral area grass-livestock digitizatal management DSS1.0 software copyright (the registration number: 2009SR043117, copyright owner (nationality): Lanzhou University: China. For the first time publication date: 2009-04-20, registration authorization date: 2009-09-28). Following research work is still in advance. 3.2 Integrated Application of 3s Technology Yuan Qing et.al.(2006) take the multi- dimensional scientific data (spatial data, attribute data) and the expert knowledge as a foundation, take the modern 3S technology as the support, establishes the Chinese grassland ecological environment monitoring and the appraisal information system. This system based on Internet,
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remote sensing technique and WebGIS and so on, and designed the system structure (to see Figure.1) to plan and to design the following content: 1) Basic data collection and reorganization (including science, society, economy, expert knowledge etc) ; 2) Spatial analysis and operation strategy and method study with the support of expert knowledge library; 3) Establishment of various multi- dimensional mathematical models; 4) Special- purpose geographic information system's design, development; 5) Design and development of computer auxiliary decision-making subsystem. The completed system has following functions: 1) Present situation accessment of grassland ecological environment (health, stable, productive forces, grass livestock balanced and so on); 2) Grassland ecosystem's change trend analysis in space and time sequence; 3) Computer auxiliary decisions-making of ecological rotection, storation, construction etc. This system not only may provide the theory basis for the national macroscopic decision-making, simultaneously provide the government department and the production unit with scienctific, reliable, timely background data and the dynamic change data, moreover benefit the ecological construction and the livestock husbandry production, the maintenance or restores the natural pasture in the ecological equilibrium state and continues forever to be used, have an important directio value in enhancing our country grassland scientific style, modernization, the informationization management level.
Space Database
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Fig. 1. Grassland ecological environment monitoring &appraisal diagram under 3s technical support
3.3 Expert System of Prataculture Ecological Construction and Development Gansu grassland ecology research institute has developed “the Gansu Province Expert system of prataculture ecological construction and development” in October, 2001.
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This system take the 3S technology and the internet as the development foundation, which can carry on point inquiry dough and polygon inquiry, including-“in where”, “is what”,”plant what”,”how to grow”--four questions. While point inquiry dough and polygon inquiry take point (approximately 1km2), township or county as the unit, which is enormous convenient for users. Main deficiencies of this system are: 1) The forage compatible research is carried on in the foundation of the grassland synthesis order classification retrieval chart,which only involves the compatibility of forage grass, not solve the forage planting and the variety compatible problem; 2) 56 kind of fine forage grass cultivation compatible chart in the system are in the investigation foundation, which is connected to spatial databases's field name, not inference results(Sun Juan, 2004). Afterward, by Lanzhou University grass farm science and technology institute Professor Chen Quangong, Ren Jizhou and Wang Jiayi (Lanzhou Gaobo computer information system engineering company senior engineer) etc completes WEST special project of the Science and Technology Department of China“Expert system of Chinese prataculture development and ecological construction” (2003BA901A20).The compact disc version is published at January, 2006. The Chinese prataculture and ecology” website based on WebGIS also opens afterward. The compact disc and the website are developed in the scientific discipline knowledge system of geoscience, agronomy and prataculture science, with 3S technology, computer and information technology. They combinethe spatial databases, more than 2100 graph images, 2 million words, 2GB system capacity , and which have retrieval, inference,demonstration, printing function; contain 23 spatial databases of the national county level administration regionalization and the national various counties remote sensing images, grassland type, soil type, cultivation forage distribution,domestic animal distribution,agriculture and husbandry resources environment specifically and so on; Contains the Chinese prataculture and ecology,prataculture knowledge library, key area of cultivating forage, the grassland management and the ecological construction, plant disease diagnoses, the prataculture science and technology, the forage growth simulation, the prataculture information, various provinces prataculture and ecology etc 12 groups of 38 main modules. The household user with simple computer operation knowledge is possible to use this software and the website inquires.Both can reply accurately “in where”, demonstration space position and correlational dependence and so on; “is anything”, demonstration environment, agricultural resource, native vegetation and so on; “plants anything”, demonstrated that suitable cultivation the forage type and recommends the improved seed; “how to plant”, demonstration cultivation managerial technique and sickness, insect, rat damage and weed's prevention method; “raises what livestock breed”, demonstrated fine livestock and livestock and poultry type and historical evolution; “how to raise”, demonstrates the science raising method of various poultry variety. Several hundred agriculture colleges and universities and the Scientific research Unit in China, more than 2300 counties may obtain “Expert system of Chinese prataculture development and the ecological construction” the software compact disc (ISBN 7-89496-798-X) freely, users may also register “the Chinese grass industry and the ecology” the website (www.ecograss.com.cn) glance over (Lanzhou University news net, 2006).
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Digital grassland technique platform of China Data and Information level
Theory and technique level Theory and techniques of grassland monitoring management
Basic database system of grassland Data standard specification
Database management techniques
cultivated pasture design and management
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Ecological measurement System simulation
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Soft component techniques Mobile Storage techniques Software and hardware technique paltform of Grassland digital monitoring management
Network techniques
Grassland production data service and technique procucts Integration of data and techniques
Information service
Production monitoring
Optimization management
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Application and demonstration level
Practical software and hardware technique products and demonstratation application
Fig. 2. Framework for the digital prataculture technique platform of China
3.4 Chinese Digital Prataculture Theory Technology Platform The grassland management and the decision-making are a huge system, which need a great deal of data and technical support. Based on this reason, Institute of Agricultural resources and regional planning, Chinese Academy of Agricultural of Sciences (IARRP-CAAS) has constructed the huge digital pratacultural technology theory platform, which build the foundation for the Chinese prataculturae sustainable development. The establishment thinking of the "digital theory and technology platform of Prataculture" is using information technology and its latest research results, and prataculture management theory, and exploring critical technology issues and related to scientific assumptions of the prataculture digital monitoring and management, from which extracts China digital grassland theory and technology infrastructure, they are summed up as three levels :Prataculture data and information, the core theory and technology, application and demonstration (see Figure. 2).
4 Small Decision Support Systems Small DSS is relatively more than big one in the farm management,such as pig farm, cattle farm's small DSS.The small DSS can realize the industrialization and the automatic control, to be quite convenient with the market trail connection, compared
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with the huge grassland area livestock husbandry. And small DSS is manoeuvring, therefore develop rapidly. Xiong Benhai (2005) has constructed “the cow fine cultivation technology platform”using RFID, PDA and wireless local network technologies,which realized the comprehensive gathering cow's individual body situation information and through calculate gain cow's date nutrition required quantity using the nutrient forecast model and the cow secretes curve model,which directs the instruction date grain formula, achieves the cow individual the fine raising goal. Wang Zhonghua (2005) uses digital technique collecting cow milk production quantity, young ingredient, amount of exercise, body situation, body weight change information, as well as cow's foundation date grain picks the appetite, through the overall system automatically controls feed's supplement plan, which realized cow nutrition need, feed design, information acquisition, cow automatic diagnosis, automatic control et al various technological means. Expert system of the alfalfa planting management and pest control developed by Beijing Intelligence Valley Science and Technology Limited Company can be used to alfalfa planting management and pest control production. (National Copyright Administration registration number: 200210952; Software copyright registration number: 2002SR2425; Patent of invention number: 02121283.X) (Bai Fengshuang, 2003). Jiang Wenlan has set up a big sustainable production model of forage resources population protection using the biocybernetics method, and take the experiment as an example, she had determined the concrete protection target and the grazing management measures, studied the unicast artifiicial pasture optimum control model with herd the countermeasure; constructed the artifiicial pasture applying fertilizer model and the grazing system nutrient cycle mechanism model, and proposed “Integrated computer fertilizer recommendation expert system for artificial pasture”.
5 Calibration and Application of Broad Model Although the overseas software's chinization is not a long-term plan, but is also an important direction.Through taking example by the overseas advanced technology can also promote the domestic DSS research to a certain extent. Institute of Agricultural Resources and regional Planning,Chinese Acedamy of Agricultural Sciences (IARRP-CAAS) introduced and improves the Australian GMDSS-GRAZPLAN for North China grassland.They used long-term observation data of the temperate grassland, fitted and adjusted its first floor model parameter, based on which, they established a suite of domestic animal system's system simulation and the dynamic management system for Chinese temperate grassland, which could accurately simulate the ungrazing grassland production and the community structure dynamics and grassland production and the community structure under different stocking rates, defferent utilization pattern (rotational grazing or forbidden grazing)in grazing situation.which can provide references for the family pasture livestock production, ecology,economically optimized management and dynamically regulation (Tang Huajun, Xin Xiaoping, 2009).
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6 New Technology Application in Grassland Management 6.1 Application of GIS and WebGIS Technology The model and the network bond is a current international agriculture model study important tendency. Expert system (ES) or DSS combine with GIS, whicn may cause ES or DSS decision-making process integrated with the geography information. Through useging GIS analysis result, we can enhance ES and DSS decision-making level. At the same time, decision-making result issuing through GIS may strengthen intuitive, and builds the foundation for the further localization implementation (Chen Liping, Zhao Chunjiang, 2002). Sun Juan (2004) established forage adaptation and returning cropland back to grassland DSS based on GIS,which acilitated Gansu Province forage seed selection for Gansu returning cropland back to grassland,that is offering decision support and basis for forage adaptation problem. 6.2 Virtual Reality Technology The virtual reality technology is a technology of reflecting the biological growth process with graphs and dynamic images. Realizing the virtual reality in GMDSS will perform forage growing and animal development process clearly with the virtual plant and virtual animal, and visually manifest the influence of various factors to the forage growing and the animal development.But there is still no advance in virtual grassland in China. Liu Shengping, Zhu Yeping (2008) have established the wheat analog modeling based on the agent technology. The agent technology involves system science, artificial intelligence, software engineering and pattern layout knowledge, and it may provide the available agent of soil, weather, irrigation, applying fertilizers, nitrogen equilibrium and water balance of the crops growth model. These agent also provide the sharing codes for re-development of the other crops models. 6.3 PDA PDA is a Personal Digital Assistant,a Pocket PC.PDA Is as the name suggests that is auxiliary individual work as a digital tool, facilitates carrying, convenient for open country using. At present, domestic and foreign data acquisition software based on the PDA already carry on the practical application in forestry, crops applying fertilizer, cadastration, medical service and many other domains(Wu Shouzhong,2007), but PDA are quite few in related research of the grassland managerial data gathering aspect. Wu Shouzhong(2007) developed the PDA grassaland rat damage data acquisition system with C# as the development kit and with technical metasyntheses of PDA, GPS, XML.He also developed application tool softwares including the spatial collection law, the settled spot collection law, the settled area collection and the metal pliers date gathering law,which realized the grassland mouse data acquisition semiautomatically, and changed the tradition field datacollection way, and raised the working efficiency(See Figure.3)
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Module for data collection based on the space
Module for data collection based on the settled area
Data collection system for monitoring ordent pest on the grasland
Module for data collection based on settled spot
Module for data collection based on days
Fig. 3. Data collection system for monitoring rodent pest on the grassland based on PDA (Wu et al,2007)
7 Prospects of Grassland Decision-Making System in China Study of GMDSS has made some achievements, such as grassland productivity model and grassland system simulation, but there is still no practical GMDSS in China. In future research, we should firstly combine the existing resources, including the remote sensing monitoring data, the ground datum and the meteorological data etc,and full use of IT technology (for example,WebGIS technology).We should complete the forage adaption assessment and the ecology regional planning to direct macroscopic region forage production. Secondly, we must research and develop GMDSS of our own proprietary intellectual property rights and suit the Chinese grassland production management profitting from domestic and foreign research foundation;and strengthen mechanism model research.Moreover enhancing overseas cooperation with the developed countries, or adjusting overseas mature model is a convenient way.For example,the introduction of Australian GRAZPLAN system by IARRP-CAAS. Simultaneously we should realize combination between the remote sensing monitor data and DSS, and realize timeliness and effectiveness of GMDSS. China has approximately 4×108 hm2 grassland, the area is no 2 in the world, we should develop our own GMDSS adapt to China grassland geography, climate and special grazing tactics, which is requested from the extensive economy to the intensive economy trend of development. We must realize the grazing management mathematically quantification and controllable; we must develop comprehensive GMDSS, as well as small grazing management decision-making calculator. Along with developement of computer network technology, small calculators may provide the online use. In brief, our country's grazing management is still the family pasture-like extensive management, There is still a very big disparity compared with the developed country. Our grazing management DSS research also just begin.Because the DSS research is time and expends-consuming work, usually, we need model research foundation,
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simultaneously need the massive data foundation and computer application ability, and the multi-disciplinary cooperation. We hope in the near future, we might realize dynamic grassland process management based on the knowledge library, the model base and the remote sensing database, and realize the virtual reality--the grassland management process and the effect present by the visual picture form in front of us. Acknowledgment. Research was supported by the earmarked fund for Modern AgroIndustry Technology Research System, key scientific and technological project of Inner Mongolia(20091403), meteorology assessment technology of grassland ecology health from meteorology industry science and technology (GYHY200906029-2) and grassland carring capacity and livestock deploy in north China meadow grassland from industry science and technology of China Ministry of Agriculture (200903060).
References [1] Xiong, B., Qian, P., Luo, Q., Lv, J.: Meticulous solution on livestock husbandry based on individual dairy cattle body conditions. In: Digital Agriculture Research Progress,Edited by general experts group of digital agricultural specialization of 863 plan, and National Engineering Research Center for Information Technology in Agriculture (NERCITA), September 2005, pp. 435–441. Chinese agricultural sciences and technology press, Beijing (2005) [2] Wang, Z.: Function and system design of digital technology in the production of dairy cattle. In: Digital Agriculture Research Progress,Edited by general experts group of digital agricultural specialization of 863 plan, and Nationa l Engineering Research Center for Information Technology in Agriculture (NERCITA), September 2005, pp. 452–454. Chinese agricultural sciences and technology press, Beijing (2005) [3] Huang, J., Wang, X., Wang, R., Hu, X.: A Study on Monitoring and Predicting Models of Grass Yield in Natural Grassland. Journal of Remote Sensing 1(5), 69–74 (2001) [4] Yan, X.: Geospatial information science (Quarterly) 2(7),117–123 (2004) [5] Liu, S., Zhu, Y.: Establish Wheat model based on Agent technology. In: Agriculture Information Technology and Management, Edited by Agricultural Information Institute of Chinese [6] Zhang, W., Dong, Y., Zhang, Q., Yuan, J., Du, Q.: Trends Analysis of Domestic and international agricultural science and technology. Information Center Chinese Academy of Sciences, http://www.docin.com/p-31936733.html [7] Digital pastoral livestock management decision support system, http://www.chinadigitalgrass.com/ [8] Wu, S., Gao, L., Shi, D., Su, H., Liang, J.: Development Data Collection System of the Rodent Pest on the Grassland Based on the PDA with GPS. Acta Agrestia Sinica 6(15), 550–555 (2007) [9] Lv, S., Duan, S., Song, B.: Dynamics Model of Grassland Agricultural Ecosystem. Acta Prataculture Sinica 4 (1990) [10] Lv, S., Song, B.: Dynamics Model of Grassland Second Production. Gansu Social Sciences (1991) (supplementary issue) [11] Lv, S., Song, B.: Study on Micro Dynamics Model of Grassland Second Production. Forage and livestock, 4–10 (March 1992) [12] Lv, X., Lv, S.: Sustainable Development of Grassland Livestock Husbandry in Main Pasturing Areas of China. Gansu Social Sciences, 115–123 (February 2003)
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Design Method and Implementation of Ternary Logic Optical Calculator* Chunzhi Li1 and Junyong Yan2,** 1
School of Mechanical and Electronical Engineering, East China Jiaotong University, Nanchang, China 2 School of Software & Communication Engineering, Jiangxi University of Finance and Economics, Nanchang, China [email protected]
Abstract. Compared with the conventional electronic computer, the Ternary Optical Computer (TOC) is the better idea for next generation computing tools because it possesses numerous data bits, enough intercom bandwidth, and inter controller made of electronic computer, but when designing optical calculators in TOC, there is much randomness that bring the manufacture of the optical calculators on lots of difficulties. In order to clear up the randomness, we have analyzed various designs of the optical calculators. In this research, a new rule, named the Decrease-Radix Design, was founded. According to the rule we established a design criterion for multi-valued logic calculator which includes eight steps. According to the criterion, all ternary logic optical calculators can be designed by a few basic units and the calculators have clear structures. It is possible to reconstruct any ternary logic optical calculator with the same basic units group by virtue of the criterion. Followed the design criterion, a hundredsbit reconfigurable ternary logic optical calculator has been designed till June, 2007. In this paper we introduce the Decrease-Radix Design rule and the design criterion of multi-valued logic calculator in detail, and also introduce the design, manufacture and the experiment of the hundreds-bit reconfigurable ternary logic optical calculator. In the end, some photos of the optical calculator and its experiment will be shown. Keywords: Design Criterion, Ternary Logic, Reconfigurable, Ternary Optical Computer, Optical Calculator.
1 Introduction The Ternary Optical Computer(TOC) Principle [1][2][3][5][11], presented by Prof. Yi Jin in 2002, in which information was expressed with no light state and two perpendicular polarization directions light (such as the vertical polarization light and the horizontal polarization light) and the three optical states can be transformed each other *
Supported by the Science and technology projects of Jiangxi Provincial Education Department (Grant No.GJJ09560) and the Youth Foundation of Jiangxi University of Finance and Economics (2008). ** Corresponding author. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 147–166, 2011. © IFIP International Federation for Information Processing 2011
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using liquid crystal and polarizer, is a bran-new idea for next generation computing tools because that it possesses of numerous data bits, enough intercom bandwidth, and inter controller made of electronic computer. After that, lots of experiments on TOC were conducted. The researchers in this area have carried out a series of experiments on the design and the manufacture of some important components, i.e. the ternary optical encoder [8][9][10], ternary optical decoder [8][9], ternary logic optical calculator [7], ternary optical half-adder and full adder [4][6], and tried to develop the corresponding ternary optical computer prototype. But when designing optical calculators in TOC, there is much randomness. Commonly, the designs of optical calculators completely depend on inspiration of designers, so it is possible that different light diagrams are gained by different designers. All these not only make the design of light diagram of optical calculator slow but also make the design quality ensured difficultly; in addition, they also bring the manufacture of the optical calculators on lots of difficulties. These disadvantages are obvious in the development of the ternary logic optical calculators. In order to solve these problems, a design criterion of multi-valued logic calculator [15][16] was presented and was applied to the manufacture of ternary logic optical calculators in this paper. According to the criterion, all ternary logic optical calculators can be designed by a few basic units and the calculators have clear structures. It is possible to reconstruct any ternary logic optical calculator with the same basic units group by virtue of the criterion. Followed the design criterion, we have designed and set up a hundreds-bit reconfigurable ternary logic optical calculator in June, 2007. In this paper we introduce the design criterion of multi-valued logic calculator in detail, and also introduce the design, manufacture and the experiment of the hundreds-bit reconfigurable ternary logic optical calculator.
2 Decrease-Radix Design Rule [15][16] The operational capability of n-valued logic calculator with two inputs can be defined by the truth table of input and output. This truth table is n×n array in which the element lies in i row and j column is denoted by cij. And each n-valued calculator must have n different physical states to represent these n values. In order to discuss conveniently, some symbolic definitions are given as follows: (1) Use τi to represent information, and all τi assemble the set i.e. Ω={τ1, τ2, …, τi, …, τn |i=1,2,…,n }. (2) Use λi to represent physical state, and all λi assemble the set i.e. Φ={λ1, λ2,…, λi, …, λn|i=1,2,…,n }. (3) LTk(n)(k=1,2,…,n) represents a truth table of n-valued logic, in which all the elements cij belong to the set Ω. (4) PTk(n) (k=1,2,…,n) represents a truth table of n-valued logic, in which all the elements cij belong to the set Φ. Definition 1: If the result is still λi when one physical state in set Φ overlaps with λi( Φ), the physical state is called the state D. It is possible that there is no the state D in the set Φ, but it is also possible that there are several states D in the set Φ.
∈
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Definition 2: If only one element in the truth table PTk(n) is not the state D, then this truth table PTk(n) is called the basis-element table BTk(n) (k=1,2,…,n). Only one element in BTk(n) is not the state D and the other (n×n-1) elements are the state D, then the BTk(n) is a n×n two-value table. Due to there are (n-1) physical states in the set Φ which are not the state D, there are (n-1) basis-element tables which have one element that is not the state D at the same position; furthermore, there are n×n positions of element in the BTk(n), thus the number of basis-element table is n×n×(n-1) totally. 2.1 Select Physical States In principle, the steady physical state which can be transferred from one state to another by apparatus can be used to represent information. Therefore there are many optional schemes of the set Φ, in which those schemes that can generate such set Φ which contain the state D are the discussion object of this paper, and these schemes can be used to implement multi-valued computer system conveniently. For example, the wavelength, intensity and polarization direction of light signal can all be used to represent information, in which the no light state is the connatural state D because that when it overlaps with any light signal which have any wavelength, any intensity and any polarization direction, the no light state seems nonentity to the result of the overlap, so it accords with definition 1. If the no light state, vertical polarization light and horizontal polarization light are selected to represent information in one system i.e. Φ= {no light state, vertical polarization light, horizontal polarization light}, there lies the state D (no light state), so the design criterion presented in this paper can be used to complete corresponding design task easily and conveniently. And if only the vertical polarization light and horizontal polarization light are selected to represent information in a system i.e. Φ={vertical polarization light, horizontal polarization light}, there is not the state D for neither the vertical polarization light fall short of definition 1 nor the horizontal polarization light. This is not the domain of this paper. 2.2 Mapping between Physical States and Information Symbols Commonly, the operational capability of logic calculator is given by the corresponding truth table LTk(n) in which the element is a information symbol, but the implement of it must depend on the physical states transfer. So firstly, the element mapping relationship between physical state set Φ and information symbol set Ω must be defined. There are (n!) optional mapping relationships totally, but different mapping relationship corresponds with different complexity of logic calculator structure. In this paper, using the state D to represent the information symbol which is the most frequently appeared in LTk(n), in this way, the final structure of logic calculator is most simple. 2.3 Derive from PTk(n) The truth table PTk(n) can be derived as following steps: (1) Select an element cij which value is not the state D from PTk(n). (2) Construct an n×n array truth table in which all elements are the state D.
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(3) Replace the element of n×n array truth table in step (2) which lies in i row and j column with the element cij in step (1). According to definition 7, this truth table (n×n) replaced is a basis-element table BTk(n). (4) Repeat step (2) and step (3) for every element cij in PTk(n) which value is not the state D. After the above four steps, some different basis-element tables BTk(n) can be derived from the truth table PTk(n), and the number of basis-element table BTk(n) is the same as the number of the element in truth table PTk(n) which value is not the state D. Considering the invariability of physical states overlap with the state D and the rule of matrix addition, the PTk(n) can be obtained by the “addition”of all derived BTk(n). This “addition” is not pure addition operation of mathematical matrix for the base of the “addition” is the invariability of physical states overlap, so it is called DH operation. The another meaning of DH operation is that the PTk(n) can be divided into the seriate DH operation expression of all derived BTk(n). Definition 3: The device that can realize overlap processing of physical states is called overlapper. Each truth table corresponds to a calculator, and the calculator corresponding to basis-element table BTk(n) is called basis-element calculator. If overlap the output state of these basis-element calculators using overlapper, then a multiplex calculator can be obtained. It is obvious that the function truth table of the multiplex calculator is the PTk(n). A n-valued calculator has n-valued input and output. But because one basiselement calculator has a n-valued input and a two-value output, so the construction of basis-element calculator is simpler than that of n-valued calculator, and it can be realized easily. If the construction of overlapper is simple, then any n-valued logic calculator can be obtained by the combination of several simple basis-element calculators using simple overlapper. This design rule is called Decrease-Radix Design.
3 Design Criterion of Multi-valued Logic Calculator According to the above rule of Decrease-Radix Design, the design criterion of nvalued logic calculator is given as follows: (1) Give the truth table LTk(n) of n-valued logic calculator ready to design. (2) Select the state D and overlapper. (3) Using the state D to represent the information symbol which is the most frequently appeared in LTk(n). (4) Mapping between the other (n-1) physical states and the remainder (n-1) information symbols freely. (5) Write the truth table PTk(n) corresponding to the LTk(n) using the mapping relationship selected by step (3) and step (4). (6) Derive from the PTk(n) according to the steps in section 2.3, some BTk(n) will be obtained. (7) Design the basis-element calculators corresponding with the BTk(n) obtained in step (6). (8) Construct the n-valued logic calculator by overlap the output of every basiselement calculator designed in step (7) using overlapper.
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Table 1. Truth table LTk(3) of one ternary logic Output c 0 m 1
Input b
0 0 m m
Input a m m m m
1 m m 1
For example, the no light state, vertical polarization light and horizontal polarization light (Denoted by W, V and H in the following tables) are selected to represent the ternary information in the system of TOC, and the no light state is the state D. Supposing that the truth table of one ternary logic is shown in Table 1, then the corresponding ternary logic optical calculator can be designed according to the above design criterion, as follows: Step 1: Write the truth table LTk(3) of the ternary logic, shown in Table 1. Step 2: The no light state is the state D, and select the half-reflect and halftransmission mirror as the overlapper. Step 3: Use the no light state (state D) to represent m which is the most frequently appeared in Table 1. Step 4: Use the horizontal polarization light (H) to represent 0 and vertical polarization light (V) to represent 1. Step 5: Write the truth table PTk(3) corresponding to the LTk(3), shown in Table 2. Table 2. PTk(3) Output c
Input b
W V H
W W W W
Input a V H W W V W W H
Step 6: Derive from the PTk(3) according to the steps in section 2.3, as follows: (1) Select the element c22=V from Table 2. (2) Construct a truth table (shown in Table 3) in which all elements are W (the state D). Table 3. Truth table (3×3 ) Output c
Input b
W V H
Input a W V H W W W W W W W W W
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(3) The basis-element table BTm(3)(shown in Table 4) is derived by replace the corresponding element of Table 3 with the element c22 selected in step (1). As the input a1 and b1 in Table 4 are the beam splitting from the input optical path a and b in Table 3 respectively, so a1=a, b1=b. Table 4. BTm(3) Output c1
Input b1
W V H
W W W W
Input a1 V H W W V W W W
(4) Select the element c33= H from Table 2. (5) Construct a truth table (shown in Table 3) in which all elements are W (the state D). (6) The basis-element table BTn(3)(shown in Table 5) is derived by replace the corresponding element of Table 3 with the element c33 selected in step (4). As the input a2 and b2 in Table 4 are the beam splitting from the input optical path a and b in Table 3 respectively, so a2=a, b2=b. Table 5. BTn(3)
Output c2
Input b2
W V H
Input a2 W V H W W W W W W W W H
Step 7: Design basis-element calculators (shown in Figure 1 and Figure 2) corresponding with the BTm(3) and BTn(3) respectively. In Figure 1 and Figure 2, a1,a2,b1 and b2 are the input optical path, c1 and c2 are the output optical path, v1,v2 and v3 are the polarizer that only permit vertical polarization light pass(Denoted by vertical polarizer in following part), h1,h2 and h3 are the polarizer that only permit horizontal polarization light pass(Denoted by horizontal polarizer in following part), LC1 and LC2 represent the liquid crystal unit which disable the optical rotation when the input optical path of light controller is not the no light state, the broken line represents the input optical path of light controller. The working principle of Figure 1 is: a closed light valve consists of v2, v3 and LC1, when input a1 is the horizontal polarization light or no light state, no light can pass through v1, the LC1 rotates light, then the valve closed and output c1 is no light state whatever the input b1 is. When the input a1 is the vertical polarization light which can pass v1 and LC1 disable optical rotation, then the light valve can let the vertical polarization light pass. At the same time,
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v1
a1
v3
v2 b1
c1
LC1
Fig. 1. Basic operation unit corresponding to BT m(3) h1
a2
h2
b2
h3 c2 LC2
Fig. 2. Basic operation unit corresponding to BT n(3)
if the input b1 is also the vertical polarization light, then it can pass through light valve to output c1, so c1 outputs the vertical polarization light. If the input b1 is not the vertical polarization light, for b1 cannot pass through light valve, c1 outputs the no light state. The conclusion can be obtained here that it is only when a1 and b1 are the vertical polarization light at the same time c1 can output the vertical polarization light, otherwise c1 outputs the no light state. So light diagram in Figure 1 realizes the BTm(3). The workong principle of Figure 2 is similar to that of Figure 1, only when a2 and b2 are the horizontal polarization light at the same time, c2 can output the horizontal polarization light, otherwise the no light state. That is, light diagram in Figure 2 realizes the BTn(3). Step 8: The final structure of this ternary logic optical calculator shown in Figure 3 is the result of overlapping the outputs of c1 in Figure 1 and c2 in Figure 2 into one output light path c using the overlapper f(here is the half-reflect and half-transmission mirror). The symbols in Figure 3 are the same as those in Figure 1 and Figure 2. The working principle of Figure 3 is similar to that of Figure 1, when a1,a2,b1 and b2 are the vertical polarization light at the same time, c can output the vertical polarization light, when a1,a2,b1 and b2 are the horizontal polarization light at the same time, c can output the horizontal polarization light. Otherwise the output c is the no light state. So light diagram in Figure 3 realizes the PTk(3). To any ternary logic, so long as there is the corresponding truth table, the corresponding normative ternary logic optical calculator can be designed step by step according to the above method. a1
v1 v3
v2 b1 b2 a2
LC1 h1
f
c
h3 LC2
h2
c1
c2
Fig. 3. Final structure of optical calculator
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4 Implementation of Hundreds-Bit Reconfigurable Ternary Logic Optical Calculator Carrying out ternary logic operation directly is one of the characters of the tenary optical computer. And ternary optical half-adder, ternary optical full adder, ternary optical multiplier and other important components are all based on ternary logic operation. So the implementaion of a well-designed ternary logic optical calculator is the precondition of the ternary optical computer prototype, and its capability and bulk determine the future ternary optical computer’s capability and bulk directly. The advantage of above design criterion is using comparatively simple basiselement calculators to “assemble” various logic calculators. This character make the reconfiguration on the hardware of the ternary logic optical calculator is possible. A hundreds-bit reconfigurable ternary logic optical calculator is implemented using the apparatus which is current in market, such as liquid crystal display, polarizer, embeded system etc. and VC etc. developing eviroments in this paper. The following introduces the design, manufacture and the experiment of this reconfigurable calculator in detail. 4.1 Design of Basis-Element Calculator According to definition 2, it can be concluded that there are 3×3×(3-1)=18 basiselement tables BTk(3) in ternary logic optical calculator. These BTk(3) and corresponding basis-element calculators Ak(3) (k=1,2,…,n) designed are shown in Table 6. Table 6. 18 BTk(3) and 18 A k(3) No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
BTk(3)
A k(3)
Table 1 in Appendix 1
Figure 1 in Appendix 1
Table 2 in Appendix 1
Figure 2 in Appendix 1
Table 3 in Appendix 1
Figure 3 in Appendix 1
Table 4 in Appendix 1
Figure 4 in Appendix 1
Table 5 in Appendix 1
Figure 5 in Appendix 1
Table 6 in Appendix 1
Figure 6 in Appendix 1
Table 7 in Appendix 1
Figure 7 in Appendix 1
Table 8 in Appendix 1
Figure 8 in Appendix 1
Table 9 in Appendix 1
Figure 9 in Appendix 1
Table 10 in Appendix 1
Figure 10 in Appendix 1
Table 11 in Appendix 1
Figure 11 in Appendix 1
Table 12 in Appendix 1
Figure 12 in Appendix 1
Table 13 in Appendix 1
Figure 13 in Appendix 1
Table 14 in Appendix 1
Figure 14 in Appendix 1
Table 15 in Appendix 1
Figure 15 in Appendix 1
Table 16 in Appendix 1
Figure 16 in Appendix 1
Table 7
Figure 4
Table 8
Figure 5
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The basis-element table lies in No. 17 of Table 6, has an element which value is the vertical polarization light when two inputs are no light state. The corresponding calculator can not be realized by liquid crystal unit without lamp-houses. A method is presented to resolve the difficulty in this paper, as follows: change the physical states of inputs, that is, replace the no light state with the horizontal polarization light, and replace the horizontal polarization light with the no light state. The working principle of Figure 4 is similar to that of Figure 1, only when two inputs, a and b, are the no light state at the same time, and change to the horizontal polarization light, then c outputs the vertical polarization light, otherwise the no light state. Light diagram in Figure 4 with the above state changing method realizes the BT17(3) in Table 7. The basiselement table lies in No. 18 of Table 6 is similar to the above, it only need to replace the no light state with the vertical polarization light, and replace the vertical polarization light with the no light state. h1
a
v1
h2 b
c
LC
Fig. 4. A 17(3) corresponding to BT 17(3)
Table 7. BT 17(3) Output c
Input b
W V H
W V W W
Input a V H W W W W W W
Changing the physical stats of inputs means the encoding method on the two basiselement calculator is different with the others. Because the calculator and the corresponding encoder are determined before the beginning of data processing, the actual operation of encoder is choosing a corresponding coding method on these optical paths which are inputs of the two basis-element calculator. This will not add anything to the complexity of encoder. So this method is viable. v1
a v2 b
h1 c LC
Fig. 5. A 18(3) corresponding to BT 18(3)
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Input b
W V H
W H W W
Input a V W W W
H W W W
4.2 Design and Manufacture of the Hardware Part Analyzing the structure of light diagrams of the eighteen basis-element calculators in Table 6, the representative structure can be abstracted (shown in Figure 6), as follows: (1) There are two beam splittings: one is the main optical path y, the other is the control optical path x which disable or enable the optical rotation of liquid crystal unit LC. (2) There is a liquid crystal unit LC in the main optical path y, the front and back sides of which has a polarizer respectively: P1 and P2. (3) The liquid crystal unit LC is light controlled.
x
Optical Controller P1
y
LC
P2 1
c
Fig. 6. Representative structure of A k(3)
Nowadays, the technology of light controlled liquid crystal [12][13][14] is matured in the laboratory. But considering the process of TOC’s research at present and the market of light modulator, at the condition that the principle can be validated by experiment, the selection of apparatuses needed abides by the principle that is the least spending of time and money. So the electronic controlled liquid crystal unit which is current in market is selected to replace the light controlled liquid crysta unit LC. Correspondingly, the optical controller is replaced with the electric controller, and Figure 6 is changed to Figure 7. The defect of this design is the low efficiency of the opticalelectric-optical control used to realize the optical-optical control indirectly. For this detect will not effect the aim of the design and experiment, considering the advantages and the corresponding disadvantages, we choose this design. For the function of optical controller in Figure 6 is realized by the function simulation of electric controller in Figure 7, the optical hardware of this system is only the main optical path y.
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Electric Controller P1
y
LC
P2 1
c
Fig. 7. Representative structure of A k(3)
The electric controller in Figure 7 has an input which is ternary signals (the no light state, vertical polarization light and horizontal polarization light), and an out which is binary signals. The output signals are used to disable or enable the optical rotation of liquid crystal unit LC. In this paper, the symbol 0 represents the output signal which disables the optical rotation of LC, and the symbol 1 represents the output signal which enables the optical rotation of LC. The electric controller can realize 23=8 control logics, the corresponding truth table is C1, C2 … C7 and C8, as shown in Table 9. Table 9. 8 truth tables of electric control logic Output Input
W V H
Symbols of control logic C1 0 0 0
C2 0 0 1
C3 0 1 0
C4 0 1 1
C5 1 0 0
C6 1 0 1
C7 1 1 0
C8 1 1 1
There are two kinds of polarizer on the both sides of liquid crystal unit LC in the main optical path y: vertical polarizer and horizontal polarizer. Thus, the hardware unit consisting of P1, LC and P2 has 22=4 different structures, as shown in Table 10. Table 10. Types of optical hardware unit Types Name V-V V-H H-H H-V
P1
P2
vertical polarizer
vertical polarizer
vertical polarizer
horizontal polarizer
horizontal polarizer
horizontal polarizer
horizontal polarizer
vertical polarizer
Then, according to Table 6, Table 9 and Table 10, the type name of hardware unit and the symbol of control logic which the eighteen basis-element calculators Ak(3) of ternary logic optical calculator belongs to, can be listed in Table 11.
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Types name of hardware unit V-V V-V V-H V-H H-V H-V H-H H-H V-V V-H H-V H-V V-H V-H H-V H-H H-V V-H
Control logic name of electric controller C4 C4 C5 C5 C5 C5 C4 C4 C6 C3 C3 C3 C2 C2 C2 C7 C2 C3
According to Figure 8 in which black areas represent the vertical polarizer, gray areas represent the horizontal polarizer and the white gridding middle area represents liquid crystal, adding corresponding polarizers on two faces of a electronic controlled liquid crystal display array(type: YMSG-G12864P-12DYSWSN), then there are four separate areas in the liquid crystal array: area V-V, area V-H, area H-H and area H-V from left to right (shown in Figure 8). For the liquid crystal array has 64×128=8192 pixels, and each pixel can be used as one optical path, then there are 64×128=8192 optical paths totally and 64×128/4 2048 optical paths in each area. Considering the function stability of real system, it is necessary to use several pixels to represent one optical path redundantly. It is use 2×2=4 pixels as one optical path in this system, so there are 64×128/16 512 optical paths in each area, correspondingly the maximum data bits of the reconfigurable ternary logic optical calculator is 512 too. Thus the hardware part of the reconfigurable ternary logic optical calculator is completed, and the practicality photo is shown in Figure 1 of appendix 2. The system circuitry board made by ourselves is shown in Figure 2 of appendix 2, which supplies the hardware interface between liquid crystal module and embedded control chips, and realizes eight control logics in Table 9.
=
=
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9+
159
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++
Fig. 8. Allocation of polarizator
4.3 Architectures of Experiment System The whole architectures of experiment system is shown in Fighre 9, wherer R represents surface lamp-house, C represents coder, P represents the hundreds-bit reconfigurable ternary logic optical calculator completed in section 4.2, D represents decoder, L represents homogenized beam of light, and S represents data stream. The coder C realizes the data stream S represented with light state by modulating from homogenized beam of light L to ternary information beams. The working principle of C was introduced in Reference 11. The decoder D is a light-electron conversion device which can convert the ternary light information to binary electronic information. User Interface Position machine
S Monitor system USB Interface
Embedded Part
S
S
L S R
C
S P
D
Fig. 9. System whole architectures
The software of this system includes two parts: position machine and embedded part. The two parts can communicate with each other through USB interface. The position machine provides user interface, operation window, USB device driver and a simple monitor system which can realize the dynamic hardware reconfiguration of the hundreds-bit reconfigurable ternary logic optical calculator, simulation display and analysis of experiment result. The embedded part controls and synchronizes coder C, logic calculator P and decoder D. Partial figures of software interface are shown in appendix 2.
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4.4 Process and Result of Experiment There is a software module in this system, which can realize the simulation display and analysis of current experiment results. So users can find errors visually in the operation interfaces directly, and the process of experiment is convenient and instant. This system has carried out almost thousands of ternary logic operation during several months. The range of data bits used in operations is from severa to hundreds. The system is steady and reliable, and the operation results are acoup sur, which correspond with the expectant results totally. It can be concluded that the design criterion of multi-valuedlogic calculator presented in this paper is validity and efficient. At present, this hundreds-bit reconfigurable ternary logic optical calculator has become a special demo system for visited and investigated. In this demo system, visitors can define any ternary logic freely, and the result of logic operation can be seen with either decoder or naked eyes when inputting any two hundreds-bit datum. Welcome anyone anytime visits the department of Computer, Shanghai University to investigate this system. The simpleness and efficiency of this system can make you surprised.
5 Conclusions In this paper we present the design criterion of multi-valued logic calculators. The advantages of the design criterion are that any logic calculator can be formed with a few basic units which have simple structures. We have applied this method to the design of the ternary logic optical calculator and have set up a hundreds-bit reconfigurable ternary logic optical calculator successfully. All these promote an investigation on the key parts and the development of the Ternary Optical computer.
References [1] Jin, Y., He, H., Lü, Y.: Ternary Optical Computer Principle. Science in China (Series E) 33(1), 111–115 (2003) (in Chinese) [2] Jin, Y., He, H., Lü, Y.: Ternary Optical Computer Principle. Science in China (Series F) 46(2), 145–150 (2003) (in Chinese) [3] Jin, Y.: Ternary Optical Computer Principle and Architecture. PH D thesis, Northwestern Polytechnical University (2002) (in Chinese) [4] Jin, Y., He, H., Ai, L.: Lane of Parallel Through Carry in Ternary Optical Adder. Science in China (Series F) 48(1), 107–116 (2005) (in Chinese) [5] Jin, Y., He, H., Lü, Y.: Ternary Optical Computer Architecture. Physical Scripta T118, 98–101 (2005) [6] Jin, Y., He, H., AI, L.: Lane of Parallel Through Carry in Ternary Optical Adder. Science in China (Series E) 34(8), 930–938 (2004) (in Chinese) [7] Jin, Y.: Design and Experiment of Ternary Logic Optical Processor. Topical Meetings on Optoinformatics, St. Petersburg, Russia, 21–23, October 18-22 (2004) [8] Sun, H., Jin, Y., Yan, J.: Research on Principle of Coder and Decoder in Ternary Optical Computer by Experiment. Computer Engineering and Applications 40(16), 82–83 (2004) (in Chinese)
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[9] Yan, J., Jin, Y., Sun, H.: Study on the Feasibility of Coding and Decoding Multi-bit Ternary Optical Signal Used in Ternary Optical Computer. Computer Engineering 30(14), 175–177 (2004) (in Chinese) [10] Huang, W., Jin, Y., Al, L., et al.: Design and Implementation of the 100-Bit Coder for Ternary Optical Computers. Computer Engineering & Science Ptess 28(4), 139–142 (2006) (in Chinese) [11] Jin, Y., He, H.-c., Lü, Y.-t.: Ternary Optical Computer Architecture. In: First International Meeting on Applied Physics, Badajoz, Spain, October 14-18 (2003) [12] Khoo, I.C., Michael, R.R., Finn, G.M.: Self-phase modulation and optical limiting of a low-power CO2 laser with a nematic liquid-crystal film. Appl. Phys. Lett. 52(25), 2108– 2110 (1988) [13] Janassy, I., Lloyd, A.D.: Low-power optical reorientationin dyed nematics. Mol. Cryst. Liq. Cryst. 203(5), 77–84 (1991) [14] Janossy, I.: Molecular interpretation of the absorption-induced optical reorientation of nematic liquid crystals. Phys. Rev. E 49(4), 2957–2963 (1994) [15] Yan, J., Jin, Y., Zuo, K.: Decrease-Radix Design principle for carrying/borrowing free multi-valued calculator and application in Ternary Optical Computer. Sci. China Ser. FInf. Sci. 51(10), 1415–1426 (2008) [16] Yan, J.: Decrease-Radix Design Principle. PH D thesis, Shanghai University (2009) (in Chinese)
Appendix 1: 16 Basis-Element Tables BTk(3) and Corresponding Basis-Element Calculators Ak(3) in Ternary Logic Optical Calculators In the following figures and tables, a and b are the input optical path, c is the output optical path, v1,v2 and v3 are the polarizer that only permit vertical polarization light pass, h1,h2 and h3 are the polarizer that only permit horizontal polarization light pass, LC represents the liquid crystal unit which disable the optical rotation when the input optical path of light controller is the no light state, RLC represents the liquid crystal unit which disable the optical rotation when the input optical path of light controller is not the no light state, the broken line represents the input optical path of light controller, W is the no light state, V is the vertical polarization light, and H is the horizontal polarization light. The working principle of following figures is similar to that of figure 1 of the text.
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Appendix 2: Photos of Hardware Practicalities and Software Interface
Fig. 1. Photo of Hundreds-Bit reconfigurable optical calculator for ternary logic
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Fig. 2. Photo of system Circuitry board
Fig. 3. Window of user input
Fig. 4. Window of simulation display
Design of Automatic Cutting and Welding Machine for Brake Beam-Axle Leping Liu, Mingdong Zhong, and Qizheng Dong Key Laboratory of Ministry of Education for Conveyance and Equipment, East China Jiaotong University, Nanchang 330013, China [email protected], [email protected], [email protected]
Abstract. Brake beam is one of the important components working in railway vehicles braking process, which directly affects the security and stability of the high-speed running railway vehicles. Through the research of the cutting and welding technology for the 209T straight plate type brake beam, this paper presents an advanced maintenance method, and designs an automatic cutting and welding machine for the brake beam-axle, then studies the basic structure and working principle for the machine in detail. The automatic cutting and welding machine has been operating properly since been used in the maintenance workshop. What is more, the maintenance of each brake beam only spends about 15 minutes, so this advanced maintenance method can improve the efficiency of the maintenance appropriately, and ensure the reliability of maintenance quality. Keywords: Brake beam-axle, Maintenance, Automatic cutting, Automatic welding.
1 Introduction Brake beam is an important component of the foundation brake rigging in railway vehicle bogie. And it is the essential device to ensure the security of the high-speed running train [1]. The 209T type brake beam withstands braking force repeatedly, and its end axles are abraded seriously, which connect with the railway vehicle’s brake shoes [2]. Due to the 209T type brake beam’s being widely used in the raising speed passenger train in china, its maintenance quality is crucial to the security of passenger train. In the traditional process of brake beam maintenance, the brake beam-axle is replaced by manual cutting and welding [3]. In this case, the welding fume, dust and radiation endanger health of the workers severely [4]. What is more, the cutting gap is not smooth, and it is difficult for workers to control the welding seam track. Based on the theoretical calculations, J.N. Chen [5] has analyzed the brake beam by using finite element software, and the simulation result has accorded with the theory calculations. Other authors, such as Y.P. Tang [6] and his colleagues, have focused on designing the numerical control system for automatic welder, which is used for brake beam of railway vehicle. Over the past years, welding robots are employed as substitutes for workers even in some developed vehicle depots, but it means high cost for most vehicle depots in china [7]. So we design an automatic cutting and welding D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 167–176, 2011. © IFIP International Federation for Information Processing 2011
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machine for the brake beam-axle, which aims at solving the problem that the traditional maintenance method can not ensure the reliability of maintenance quality for break beam. Previous relevant researches [8, 9] have provided a certain reference for the design of automatic cutting and welding machine. The advanced machine improves the efficiency of the maintenance appropriately, and gives full play to the advantages of the computer numerical control system with high precision, good stability, and simple operation.
2 Maintenance Process Analysis for End Axle 2.1 Maintenance Process Requirements of Brake Beam The 209T type brake beam is composed of two end axles, two groups of pulling boards and a brake beam body. And the end axle consists of cylinder and cone. The cylinder’s diameter is
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tion, the cone is welded with the brake beam body, which thickness is 20+1 0 mm. The
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overall structure of 209T type brake beam is shown in Fig.1.
200+1
1 end axle; 2 pulling board; 3 brake beam body; 4 sleeve gasket working surface; 5 brake shoe working surface. Fig. 1. The structure diagram of 209T type brake beam
Due to sleeve gasket working surface of end axles being protected effectively by the sleeve gaskets, they are not abraded. However, the brake shoes working surface are abraded seriously. Then the maintenance process of 209T type brake beam must meet the following requirements: • •
Dimensional Precision (as shown in Fig. 1). Position Precision
The symmetry error of two end axles should be less than 0.5 mm in the direction of thickness of the brake beam body, and their perpendicularity error that takes for reference with plane A should also be less than 0.5 mm. In addition, the permissible error of coaxiality for two end axles should be less than 1mm. Finally, the two groups of pulling boards take center line L1 for their symmetrical line.
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• Tensile Strength The repaired brake beam must take repeated tensile stress test, and permanent deformation can not emerge. • Abrasive Hardness The carburized depth of end axle must reach 0.8 1.5 mm, and Rockwell hardness of the cylindrical surface should reach HRC40 55.
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2.2 Key Technology for Maintenance Process First, the maintenance process is not only the welding process, it must be in accordance with following technological process: “locating and clamping the worn brake beam → cutting the worn end axles → locating and clamping the new end axles → welding. ” As is shown in Fig. 2, the brake beam body should be welded with the new end axles in double-side; furthermore, their welding trace must follow the cutting trace appropriately. Therefore, it is significant to apply the numerical controlling method to control the welding trace.
welding seam
slag inclusion
brake beam body
cutting thickness Parts to be cut
the worn end axle
Parts being cut
the new end axle Parts to be welded
Fig. 2. The maintenance process of 209T type brake beam
In addition, there are many serious technological problems in traditional process, such as lack of fusion, incomplete penetration and slag inclusion. In this case, there will exist potential danger in the high-speed running passenger trains. Accordingly, reasonable cutting and welding process parameters must be adopted to reduce this sort of defects. Finally, serious welding heat deformation occurs frequently in the traditional maintenance process. And its coaxial error can not meet the process requirement. Thus, a locating and clamping device must be adopted to prevent the welding heat deformation efficiently.
3 Scheme Design of Automatic Cutting and Welding Machine 3.1 Technical Scheme of Automatic Locating and Clamping 3.1.1 Locating the Brake Beam Body As is shown in Fig. 1, the brake shoes’ working surface is abraded seriously. However, sleeve gasket working surface of end axles are unworn. In this case, sleeve gasket working surface and end-face of the cone can be used as automatic cutting and welding
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location datum. Therefore, the locating device of automatic cutting and welding machine can find the center line L1, L2 and center plane B rapidly, and locate the brake beam body accurately [10]. 3.1.2 Clamping the Brake Beam Body To cut the worn end axles and weld the new end axles accurately, the brake beam must be clamped stably. As is shown in Fig. 2, the worn end axles will be cut after locating the brake beam body accurately, so they can not be used as clamping parts. In contrast, the plane B exists as the center plane of the brake beam body in the direction of thickness during the whole maintenance process. Thus, the plane B can exist as datum plane for locating and clamping the brake beam body. And the automatic centering mechanism can achieve this function appropriately. 3.1.3 Locating, Clamping and Rotating Device The end axle can be located on the V-shape block by outside column surface accurately. What is more, the device can achieve several functions for the new end axle, such as locating, clamping and rotating. Accordingly, the welding process of new end axle is carried out with the following steps. First, the new end axles must be located and clamped by the device accurately. Then, the drive boxes take the new end axles to the accurate welding position, and the new end axles are welded with brake beam body in single-side. Finally, the rotational device turns the brake beam over by 180º, and the new end axles are welded with brake beam body on another side. And the mechanical structures of automatic cutting and welding machine are shown in Fig.3.
1,6 drive box; 2,5 bracket; 3 machine tool bed; 4 brake beam; 7,12 rotational device; 8,11 clamping device; 9 automatic cutting and welding device; 10 moving workbench. Fig. 3. The mechanical structures of automatic cutting and welding machine
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3.2 Technical Scheme of Automatic Cutting There are many kinds of thermal cutting methods for practical application, such as plasma cutting, oxyacetylene cutting and laser cutting. Unfortunately, due to the high cutting cost, laser cutting is not suitable to be adopted in domestic vehicle depots. In this case, the appropriate cutting method must be chosen between plasma cutting and oxyacetylene cutting. Plasma cutting is applied extremely widely in the steel plate cutting industry, such as cutting carbon steel, stainless steel, aluminum, copper and other metal materials [11]. The local melt of steel is carried out by the high temperature plasma arc, and molten metal is blown away by the high speed plasma jet. Oxyacetylene flame is suitable for cutting low-carbon steel materials. First, the oxyacetylene flame preheats the metal to its igniting temperature, and then the metal is burned violently in the high temperature oxygen stream. The molten slag is blown away by the high pressure oxygen stream. Afterwards, the metal is preheated under the combined action of the heat of oxyacetylene flame and combustion heat. Obviously, this process continues until the steel plate is cut down. As the material of brake beam and welding seam is low-carbon steel, in this case, both oxyacetylene flame and Plasma can be adopted to cutting the worn end axles. However, the thickness of brake beam body is 20 mm, and the single-side thickness of welding seam is about 5 10 mm. Accordingly, the actual cutting thickness is almost about 30 40 mm. As is shown in Fig. 4, when the cutting thickness is more than 30mm, the cost of plasma cutting will be increasing rapidly, especially compared with oxyacetylene cutting. This is because that the expensive dedusting system must be adopted during the plasma cutting. From the economic aspect, the oxyacetylene cutting takes priority over plasma cutting.
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As is shown in Fig. 5, when the cutting thickness is less than 30 mm, the speed of plasma cutting is significantly faster than that of oxyacetylene cutting, otherwise, it decreases dramatically. In contrast, the cutting speed curve of oxyacetylene is nearly level.
等plasma 离 子cutting 切 割 70A 70A 等plasma 离 子cutting 切 割 150A 150A plasma cutting 300A 等 离 子 切 割 300A 等plasma 离 子cutting 切 割 500A 500A 氧oxyacetylene 乙 炔 火 焰cutting 切割
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In view of the cutting efficiency and cutting cost, low-carbon steel thickness below 30 40mm is suitable for oxyacetylene cutting. Consequently, oxyacetylene flame cutting is adapted appropriately to cutting the worn end axles. 3.3 Technical Scheme of Automatic Welding The brake beam is located at the bottom of railway vehicle, although it is cleaned before maintenance, its surface is still covered with rust and dirt. However, the carbon dioxide arc welding is insensitive to rust. What is more, it is very suitable for automatic welding with the excellent welding process, including high welding speed and excellent weld appearance quality. In addition, the trapezoid slot of brake beam body has a low forming precision, because of the oxyacetylene flame cutting. And the preset welding gap between the brake beam body and the new end axle is almost about 3 4 mm. In this case, the welding trace must follow a short and tortuous path (as shown in Fig. 6) according to our experiment results.
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Fig. 6. The welding path of new end axles
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4 Main Cutting and Welding Parameters The cutting parameters have a great influence on cutting quality, such as heat affected zone, cutting width, cutting dross and roughness. And the optimal cutting parameters can be determined by orthogonal experimental design, and suitable for the balanced pressure cutting nozzles, as shown in Table 1. Similarly, the main welding parameters such as welding current, arc voltage and welding speed have been optimized by the orthogonal test. The inverter CO2 welding machine's type is NB-350K. And its optimal parameters are shown in Table 2.
Table 1. The optimal cutting parameters
Nozzles 1 2
Thickness ( mm ) 30 30
~40 ~40
Speed ( mm/min ) 320 280
Gas pressure Gas consumption ( Mpa ) ( m3/h ) Oxygen Acetylene Oxygen Acetylene 0.5 0.07 2.5 0.34 0.65 0.07 3 0.47
Table 2. The optimal welding parameters
Weld modes
Current (A)
Voltage (V)
Welding spot size ( mm )
Spot weld
190
21
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210
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continuous
400
Second weld layer
250
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continuous
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~20
15
Speed ( mm/min )
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5 System Design of Automatic Cutting and Welding Machine 5.1 System Design The automatic cutting and welding machine is shown in Fig. 7. It is composed of machine tool bed, drive boxes, cross-type moving workbench, automatic cutting and welding device, clamping devices, brackets, hydraulic system, numerical control system and welding controller. And the cutting gun and welding torch are installed on the automatic cutting and welding device, which is located at moving workbench.
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1 hydraulic system; 2 machine tool bed; 3,12 drive box; 4,11 bracket; 5,10 clamping device; 6 automatic cutting and welding device; 7 welding torch; 8 cutting gun; 9 moving workbench; 13 numerical control system; 14 welding controller. Fig. 7. The system design of automatic cutting and welding machine
5.2 Working Principle The whole technological processes have been identified as follows: To lift brackets to the locating position, and locate the brake beam roughly by center line L1 and L2 → To clamp the brake beam body and locate it precisely by center plane B → To retract the brackets → To cut the worn end axles → To clamp the new end axles →To spot-weld the new end axles with brake beam body (As shown in Fig. 8) → To weld the new end axles in single-side → To unclamp the clamping devices and turn the brake beam over by 180º → To weld the new end axles in another side → To unclamp all clamping devices and take down the repaired brake beam.
Fig. 8. Automatic welding device in operation
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5.3 Main Technical Parameters Main technical parameters of the automatic cutting and welding machine have been identified as follows: • Stroke of moving workbench In the direction of X axis: 300 mm; In the direction of Z axis: 1600 mm. • Stroke of drive box: 200 mm; Rotation angle: 180°. • Cutting speed: 280 mm/min. • Welding speed: 400 mm/min. • The total power: 24 KW. 5.4 Experimental Verification There is no permanent deformation after the repaired brake beam takes repeated tensile stress test. As is shown in Fig. 9, the pulling force acting at each group of pulling boards is 35 kN [12]. In addition, tensile stress tests show that the tensile strength of repaired brake beam has completely reached the process requirement.
Fig. 9. Repeated tensile stress test
The curves of coaxiality under different process conditions are shown in Fig. 10, and coaxiality of improved process is less than the permissible error. These results indicate that the advanced maintenance method is feasible to control the error of coaxiality, and the improved process takes obvious priority over original process. 旧 工艺同 轴度 同轴 度允差 新 工艺同 轴度
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6 Conclusions An automatic cutting and welding machine for the brake beam-axle, to be employed in a vehicle depot, was designed. This maintenance process has the advantages of convenient clamping and accurate locating. This designed machine was set up and tested, and experimental results show that the designed machine is appropriate for practical application. After refitting the clamping device and changing the control program, this automatic cutting and welding machine could be applied to the field of maintenance for the similar type brake beam. The application of such low-cost automatic cutting and welding machine, which is urgently needed in many vehicle depots in China, not only improves the efficiency and maintenance quality, but also protects the operators from hazardous circumstances.
References 1. Wang, H.Z., Wang, H., Shang, Y.J.: Strength character research on brake beam for type of 209 bogie. Journal of Lanzhou Jiaotong University 28, 121–123 (2009) 2. Song, H.L.: Technological measures to guarantee the coaxiality for brake beam. Railway Locomotive & Rolling Stock Workers (7), 10–13 (1998) 3. Wang, R.J., Wang, S.: Investigation and analysis on problems existing in inspection and repair of brake beams. Rolling Stock 39, 26–27 (2001) 4. Li, G.Y., Dong, M.D., Zhao, J.Y.: Design and practice of new type pneumatic control system for trunk brake beam electric welding workshop. In: Hydraulics Pneumatics & Seals, vol. (5), pp. 46–47 (2001) 5. Chen, J.N.: Finite Element Analysis for Brake Beams. Journal of Rolling Stock 1, 30–33 (2000) 6. Tang, Y.P., Wang, J.M., Feng, Q.X.: Automatic welder based on DSP motion control card for van brake beam. Manufacturing Technology & Machine Tool (2), 35–37 (2005) 7. Xin, H.B.: Application of Welding robot in Manufacture of Bogie frame. Journal of Machinist Metal Forming 24, 53–55 (2008) 8. Fu, P.X.: Application Research on Automatic Cutting and Welding process for Brake Beam-Axle. Shanghai Railway Science & Technology 1, 21–23 (2008) 9. Zhou, L.: Design and analysis of multi-function auto-welding machine tool control system. Machine Tool Electric Apparatus 3, 60–61 (2009) 10. Di, R.K., Fan, X.H., Fan, X.Y.: Mechanical Manufacture Engineering. Zhejiang University Press, Hang Zhou (2001) 11. Hang, Z.X., Ma, X.Z., Ma, Y.J.: Position of plasma cutting in thermal cutting methods. Journal of Shenyang University of Technology 21, 479–481 (1999) 12. Railway Ministry of the PRC, Load Test Methods for TB/T 1978-2007 Brake Beams. China Railway Press, Beijing (2007)
Design of Multifunction Vehicle Bus Controller Zhongqi Li, Fengping Yang, and Qirong Xing College of Electrical & Electronic Engineering, East China Jiaotong University, Nanchang, P.R.China [email protected]
Abstract. The Train Communication Network (TCN) is widely used in highspeed train. However, its core technology - Multifunction Vehicle Bus Controller (MVBC) is owned by foreign companies, which limits the development of high-speed railway in China. Based on the principle of Multifunction Vehicle Bus(MVB), and analysis of real-time protocol and functions of bus controller to be achieved, this paper describes the design of MVBC which is divided into seven modules, Encoder, Decoder, Telegram Analysis Unit(TAU), Configuration Memory, Traffic Memory Controller(TMC), Arbitrator and Microprocessor Control Unit(MCU). And then it designs each module with VHDL in the integrated development environment of Quartus developed by Altera Company. A new MVBC is developed with FPGA. The test shows that it can take place of MVBC Application Specific Integrated Circuits (ASIC).
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Keywords: TCN, MVB, MVBC, FPGA.
1 Introduction The TCN bus was standardized in the Plenary Session of the IEC Technical Committee 9, Kyoto, Japan, October1999, which resulted to the IEC 61375 Standard. The IEEE Vehicular Society also standardized the TCN bus, which resulted to the IEEE 1473-T Standard. The main goal of the TCN is to set a single train equipment specification that is compliant with the requirements/needs of different railway service providers and to warrant the interconnection of any number of different vehicles/units from possibly different manufacturers in the same train. MVB is one component of TCN. The MVB is the Vehicle Bus specified to connect standard equipment, located in the same vehicle, or in different vehicles in the TCN. The MVB can address up to 4095 devices, of which 256 are stations capable of participating in message communication. In order to allow these devices to communicate with each other, a common communication interface card is designed which is independent of the chosen physical layer and functions associated with each device. The MVBC is an ASIC chip which realizes the physical and major parts of the link layer protocol of the MVB.
2 System Description and Architecture The MVB Controller contains the encoders/decoders and the logic to control the Traffic Memory, which decodes the incoming frames and addresses the Traffic Memory D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 177–183, 2011. © IFIP International Federation for Information Processing 2011
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accordingly. This paper describes the design of MVBC which is divided into seven modules that is Encoder, Decoder, Telegram Analysis Unit(TAU), Configuration Memory, Traffic Memory Controller(TMC), Arbitrator and Microprocessor Control Unit(MCU). Fig 1 is MVBC architecture. MVB BUS
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JTAG Interface Decoder
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Fig. 1. MVBC architecture
Implementation steps of the controller function as follows, chip power, reset, configure the device address, models and other services, start work. When sending data, MCU reading the corresponding data from Traffic Memory(TM). write to send buffer, then MCU send instructions of send data to the encoder. When accepting data, the Manchester decoder receiving signals from the bus controller, upon decoding, verification and data is written in receive buffer, and notifies the main control unit. MCU read data from the receiving buffer, writes corresponding area of TM. MVBC communicate with the microprocessor through TM which uses dual-port RAM. 2.1 Encoder Encoder engages in Manchester encoding of Master_Frame and Slave_Frame, and generation and sending CRC check sequence. Above-mentioned work is controlled by MCU. The specific tasks of the module are as follows: (1) The parallel data are extracted from the buffer, (2) The parallel input data transform into serial data suitable for MVB, (3) Add to delimiter for ready to send data, (4) According to the length of ready to send data, add one or more 8-bit CRC check_sequence. (5)Manchester encode for data to be send in order to improve communication quality. Structure of encoder according to the above design of the task is as follows, Digital control unit, Parallel Convert Serial Unit, Frame Delimiter Unit, FIFO unit, Multi-selector unit, CRC Generation Unit, Manchester encode unit. The structure is shown in Fig 2. Control signal from MCU Digital Control Unit
Frame Delimiter Unit Delimiter
Data_in[n:0] FIFO
Parallel Convert Serial Unit
CRC Generat -ion Unit
CRC check
Data
Mul t i selector Unit
Fig. 2. Encoder architecture
Manche s t e r Data_out encode Unit
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Digital control unit plays a controlling role of the operation of the other. First Input First Output(FIFO) unit is the input data buffer. Frame delimiter unit is the role as follows; add to Start_Bit for frame, Start Delimiter of Master_Frame, Start Delimiter of Slave_Frame. Parallel Convert Serial Unit read data from buffer and convert parallel data to the serial data. Manchester encode unit encodes data on the communication. Outgoing data CRC check sequence generated by CRC generation unit. When the data output, Multi-selector unit selects the starting delimiter, outgoing data and the CRC check code. 2.2 Decoder The main functions of the decoding module include Manchester decoding and error detection of received data, then decoded without error serial data convert to parallel data which stored in the buffer zone and supply of top applications. Decode is the anti-process of encode which will have decoded data encoded, it is also the original appearance of data. The task of error detection mainly includes the error detection of CRC check code, error of frame length and error of Manchester skipping, etc. Decoder includes decoding control unit, the detection of start bit unit, delimiter detection unit, Manchester decode unit, Serial Convert Parallel Unit, FIFO unit, CRC check unit and the length check unit. The structure is shown in Fig 3.
Fig. 3. Decoder architecture
2.3 Memory Configuration Memory Configuration module read and write configuration registers of MVBC and CPU which consists of 27 8-bit configuration registers and 4 8-bit registers buffer which composed of PCS. The following memory is used in MVB communication, TM, TxBuffer, RxBuffer and InterRegister whose access mode include internal and external access and internal and internal access. Internal and external access include CPU←→TM, CPU←→InterRegister, RXBuf→TM, TM→TXBuf, TM→MFR. Internal and internal access include RXBuf→MFR, MFR→TXBuf.,Two sets of configuration register access mode is designed to achieve these two access functions which includes internal access and external access, so you can guarantee that two access patterns at the same time, and without conflicts and impact.
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Internal access mode use a dedicated signal line to achieve an internal read-write access in which read access is through the direct connection method to achieve fast access, while the form of written interview by paragraph to visit it to each configuration register which is divided into paragraphs (up to 16), identify by paragraph address and data. So long as we know the corresponding data segment address and the segment can be achieved within the configuration register access. In the external access mode, then use a common bus address to visit. As the external access is targeted TM or CPU, on the TM and the CPU access is controlled by TMC and ARB. 2.4 Telegram Analysis Unit TAU is mainly responsible for the analysis of telegram. The received packet is passed to the control unit results MCU, then according to the feedback control unit to the corresponding treatment. There are eight kinds of situations. TAU is composed of timer and state machine. Fig 4 is TAU architecture.
Fig. 4. TAU architecture
State machine is responsible for the analysis of the telegram and the corresponding control. Timer with the state machines perform a variety of timing tasks, while ensure the successful completion of state machines to switch among various states and the corresponding operation. 2.5 Traffic Memory Controller TMC is composed of sink time manager、 master state machine、 word access state machine and selector. Master state machine controls all of TM and generates control sequences. Each word can be accessed by controlling word access state machine. When word being accessed completely, the word will automatically add an access counter, up access to all word. Word access state machine is formed by the five state, IDLE STATE, ACC_BEGIN STATE, WAIT STATE, W_TMRDY STATE and DATA_VALID STATE. Transition among states is shown in Fig 5.
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Fig. 5. Transition among states
2.6 Traffic Memory Controller Arbitrator is used to solve the conflict when CPU and MVBC access TM at the same time, arbitrator at the same time allows only one access TM. 2.7 Microprocessor Control Unit MCU is a core part of MVBC almost control all the other modules work, play a role in overall control. MCU is not directly involved in concrete action, but by controlling the other modules to complete the appropriate action treatment. MCU is composed of the distribution of Master frame, port pretreatment, port post-processing, Transport Data Unit, command processing unit. MCU architecture shown in Figure 6.
Fig. 6. MCU architecture
3 Simulation Fig 7 and Fig 8 shows the simulation result of Master Frame of process data and Slave Frame of process data simulated in Quartus . In Fig.7, F_code is 0000 which means 16 bit process data. The corresponding response frame is 16-bit. The last 12 bit of master frame is Logical address of process data. Data_out is main frame of process data which includes a frame header, frame end, and CRC checksum. Send_end is high that means sending master frame of process data is over. The delimiter and checkout value is successfully added. The simulation result of Salve Frame is shown in Fig.8.
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Fig. 7. Simulation of Master Frame of process data
Fig. 8. Simulation of Salve Frame of process data
Fig 9 shows the simulation result of Master Frame of message data simulated in Quartus . In Fig.9, a Master Frame contained data is encoded.
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Fig. 9. Simulation of Master Frame of message data
4 Conclusions The paper proposes a novel MVB design method using SOPC technology. The proposed MVB controller was successfully tested at a mixed MVB environment. It combines CPU and MVB controller into one single FPGA, so this method can save PCB space and reduce total power consumption. The availability of multi million-gate
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FPGA devices and SOPC technology has opened the possibility to create complex single chip systems and can accelerate system performance remarkably. With the SOPC technology, we have created a novel design and implementation method of the MVB controller. This method can great reduce the chip numbers and card size and power consumption relative to the traditional method. And the design is based on a soft IP core, so it can be easily integrated into other applications.
Acknowledgement The work described in this paper has been supported by Foundation of JiangXi Educational Committee (GJJ09203).
References [1] Electric Railway Equipment—Train bus—Part1: Train Communication Network, International Electro technical Commission (IEC), IEC 61375-1 Ed.01 (1999) [2] SIEMENS Transportation Systems, MVB_Controller ASIC, MVBCS1, Data Sheet (October 2001) [3] Zhang, S., Zhang, S., Huang, S.: CRC Check the FPGA to achieve parallel computation. Computer Technology and Development (2), 26–62 (2007) [4] Cai, Y.: Multifunctional compartment bus controller (MVBC) Research and Design, Master’s thesis. Southwest Jiaotong University, Chengdu (2005) [5] Jin, S., Wang, J.: FPGA-based realization of CRC encoder. Modern Electronic Technology (24), 18–22 (2005) [6] Jiang, W., et al.: Based on the VHDL language, multi-purpose vehicle bus encoder design and analysis. Railway Communications Signal Engineering (10), 9–12 (2008) [7] Lin, F., Ren, Z., Liu, C.: Manchester coding technology based on FPGA design. Modern Electronic Technology (17), 55–59 (2007)
Detection of Soil Total Nitrogen by Vis-SWNIR Spectroscopy Yaoze Feng1, Xiaoyu Li1,2,*, Wei Wang1, and Changju Liu1 1 College of Engineering, Huazhong Agricultural University, Wuhan, China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, China {yzfeng,lcj94007}@webmail.hzau.edu.cn, {lixiaoyu,wangwei}@mail.hzau.edu.cn
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Abstract. Measurement of soil total nitrogen (STN) is urgently important concerning requirement of precise and quantitative fertilizer application. To overcome the shortage of routine chemical detection, vis- short wavelength near infrared spectroscopy (Vis-SWNIRS) was employed as an accurate, cheap and timely alternative. Kennard-Stone algorithm was utilized for sample set partitioning, where 22 of the 32 samples were selected as calibration set, and the remaining 10 were included in validation set. No outliers were discovered under criterion based on spectral Mahalanobis distance and Dixon testing. Partial least squares regression (PLSR) was used to build STN detection model based on Vis-SWNIRS with cross validation by leave-one-out method. As a result, 5 principal components turned to be optimal considering model performance, where correlation coefficients for calibration and validation were 0.9724 and 0.8691, respectively, with PRESS (Prediction Residual Error Sum of Square) of 0.0684. It is feasible to detect STN by Vis-SWNIR spectroscopy. Keywords: Soil; Total Nitrogen, Vis- Short Wavelength Near Infrared Spectroscopy, Data Set Assignment, Outlier Detection.
1 Introduction Soil nitrogen content is one of the most important factors that affect modern agriculture, and it is attributing a lot to improvement of people’s living standard [1]. However, it is also among the plant nutrients which are extremely hard to manage effectively. If ill treated, its negative impacts towards environment, quality of agricultural products as well as human health will be tremendous. For example, if too much nitrogen is employed, there will appear either eutrophication of surface waters or underground water contamination to some extent. Adversely, we can easily find poor growth of the crops and eventually lower outputs if nitrogen is inadequately applied. As a result, it seems increasing urgent to determine soil total nitrogen especially under circumstances of global food shortage and safety problems. But current methods mainly rely on chemical test which is time-consuming and expensive although high accuracy is its privilege. A fast and cheap but meanwhile precise method is more promising and actually in great demand in practical application. *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 184–191, 2011. © IFIP International Federation for Information Processing 2011
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Near infrared spectroscopy has gained fast development in recent years and is applied successfully in many fields, such as agriculture, food, medicine, petrochemical industry, and so on [2-6]. The use of near infrared spectroscopy into detection of soil total nitrogen(STN) starts from Dalal and Henry’s research, whose results demonstrated the feasibility of this technology in calibrating spectra data with chemical reference of STN, and 1702nm, 1870nm, 2052nm were recognized as featured wavelengths[7]. Chang et al. [8] Employed independent spectra to determine STN other than previous methods that relied on the close relationship between levels of nitrogen and carbon content. Further, plenty of work was conducted to study different factors that may affect determination of STN by NIRS. For example, Reeve and McCarty[9] discovered that a wider range of soil types would lead to poorer performance of established calibration models, while Wu studied the influence from soil particle size and water moisture content[10, 11]. What is more, Bao et al. [12] optimized the illuminating angle and height. Several attempts were made to understand the feasibility of NIRS on determination of total nitrogen of undisturbed soil samples. For instance, Sun et al. [13] studied black soil in Northeast China, and found that the accuracy of prediction can be improved by enlarging variance of STN values. Besides, Michel reached satisfactory results in establishing NIRS-STN model by utilizing first and second derivative [14]. However, very rare research considered the significance of outlier detection and data set partitioning, which also have strong impact on model performance. The purpose of this work is to evaluate Vis-NIRS as a tool for sensing TN of paddy soil in Southern China, and to assess feasibility of establishing short wavelength calibrations for STN. Specifically, this research addressed the following objectives: (i) to assign the soil samples into two groups, that is, calibration set and validation set, by using Kennard-Stone algorithm; (ii) to detect potential outliers in the calibration set; (iii) to qualify STN content after establishment of STN-Vis-NIRS calibration model.
2 Materials and Methods 2.1 Soil Sample Collection and Preparation Soil samples used in this study were collected from paddy experimental plot in Huazhong Agricultural University. To ensure variance of levels of STN, an S-type sampling route was employed to collect the surface layer soil (0-20cm). Totally, 32 samples were gained. They were packed into plastic bags and put into a climate incubator for preservation at 4 . Then the soil samples were oven-dried at 105 for 24 hours following National Standards of China (GB7172-1987) before both spectral scanning and chemical experiment.
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2.2 Vis-Shortwave Near Infrared Spectroscopy Measurement Samples were placed into aluminum specimen boxes with diameter of 55mm and height of 33mm. A fiber-type spectrometer usb4000-uvvis/nir256 (Ocean Optics, USA) was employed to scan the soil spectra, where wavelength range was set as 400900nm, with an increment of 0.21nm. During spectral measurement, to cover the utmost area, vertical distance between the fiber-optics probe and sample surface was
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determined as 25nm, since the illuminating angle of the probe was 12.5º. Each spectrum was obtained by taking the average of two individual spectrum of the same sample measured at different rotation angles, while each of the individual spectrum was the outcome of 32 scanning to the sample. Fig.1 shows the soil spectra acquired.
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2.3 STN Determination by Laboratory Analysis Before chemical experiment, the dried samples were smashed and passed a 2mmdiameter sieve. An automatic nitrogen determination apparatus ATN-300 (Hongji, China) was utilized, and its principle abides with National Standards of China GB7173-1987. A detailed description of the STN values was given in Tab.1. Table 1. Statistics of soil total nitrogen content
Calibration set Validation set
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Min. (%) 0.07 0.14
Max. (%) 0.98 1.12
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3 Vis-NIR Spectroscopy Prediction 3.1 Data Set Partitioning Data set assignment was realized through employing Kennard-Stone algorithm [15], which was based on Euclidian distance between samples. Given each row reprents a sample and each column stands for reflectance values for all samples at one specific wavelength in the spectral matrix, to include a certain number of samples, say, Num, into calibration set, the following calculation can be performed: (i) To calculate spectral Euclidian distance between each two samples, where the distance between sample i and j is denoted as E(i, j). And the two samples that make the largest distance are picked out. For easy expression, the two selected samples are named after a and b, respectively;
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(ii) To determine the distance between each of the remaining samples with sample a and b, respectively, denoted as E (m,a) and E (m,b) where m≠a, b; (iii) For each sample not chosen, the minimum value among the distance between this sample and the selected samples is deemed to be a corresponding reference, that is Dm=min(E(m,a), E(m,b),…) while the Nth selected sample is the one whose reference is larger that that of other samples N=index(max(Dk)); (iv) To repeat step (iii) until the desired Num samples are chosen. In this study, 22 samples were categorized into calibration set while the other 10 were included in prediction set by performing Kennard-Stone algorithm. 3.2 Outlier Detection Spectral Mahalanobis distance (M-distance) of a sample is the distance between the spectrum of this sample and the average spectrum of the sample set, and it is a frequently used method for outlier detection [16, 17]. The definition of spectral Mahalanobis distance of the ith sample can be described as: Di2 = (ti − t )Cov−1 (t )(ti − t )′
(1)
Mahalanobis Distance
Where ti is the score vector of the ith sample, and t and Cov are the average score and covariance of all samples in calibration set, respectively. 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 19 31 3 21 13 17 12 4 24 6 22 18 1 5 28 32 14 25 7 9 16 29 Sample index
Fig. 2. M-distance of samples in calibration set
Dixon testing [18] was utilized to discriminate outliers. Firstly, according to the number of samples as well as the reference form given in National Standards (GB/T 4883-2008), statistical value of D22 and D’22 were calculated. Secondly, D’22 and max (D22, D’22) were compared with the threshold of low-end and high-end values at defined discrimination level, respectively. Specifically, if D’22 and max (D22, D’22) are smaller than their corresponding thresholds, the samples tested are not outliers, and vice versa. In this study, no outlier was found by employing this method.
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3.3 Partial Least Squares Regression and Prediction In particle least squares regression, concentration matrix of n components of m samples, Y= (yij) n×m, as well as absorbance matrix of n samples at p wavelengths, X= (xij) n×p, are decomposed into the form of eigenvectors, say,
Y=UQ+F
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Where U n×d and T n×d are characteristic factor matrix for component concentration and absorbance, respectively, and d is the number of representative components; Qn×m and Pd×p is loading matrix of concentration and absorbance, respectively; En×m and Fn×p are residual matrix of concentration and absorbance, respectively[19]. The regression model built can be expressed as:
U=TB+Ed
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Where Ed is composed of random error, while B is diagonal matrix of regression coefficient. Thus, for unknown samples, only with their spectral value, we can obtain the chemical concentration by calculating
y=x (UX)’BQ
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In this study, we employed “autoscale” as preprocessing method and leave-one-out cross validation was performed to test the stability of the established model. In this study, 5 principal components (PCs) were selected, because as Fig. 3 indicated, when the number of PCs were smaller than 5, there appeared sharper decreasing of RMSEC than that when more than 5 PCs were utilized. Finally correlation coefficients for calibration and validation were achieved as 0.9724 and 0.8691(refer to Fig. 4), respectively, with PRESS (Prediction Residual Error Sum of Square) of 0.0684. However, there seemed to be some difference between calibration result and validation output. This may probably due to sample acquisition method, because we collected the samples randomly and no adjustment was implemented to keep STN levels in great range. What is more, a small sample set (only 22 samples are included in calibration set) would also take the responsibility. However, a low PRESS indicated that the established model is acceptable.
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Fig. 3. Determination of optimal number of PCs
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Fig. 4. Predicted vs. measured STN
Additionally, as Fig. 5 illustrated, there was no sample that had too much influence on model performance, that is, no outlier was discovered, which is consistent with Mahalanobis distance-Dixon method.
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Fig. 5. Leverage vs. student residual plot
4 Conclusions Visible shortwave near infrared spectroscopy (Vis-SWNIRS) is promising in sensing soil total nitrogen. In this study, data set assignment method and outlier detection criterion were utilized to enhance both precision and stability of the calibration model. 5 PCs were chosen as optimal rank to establish the calibration model, and correlation coefficients for calibration and validation were gained of 0.9724 and 0.8691, respectively. Additionally, though based on small sample set, this model is stable since PRESS was as low as 0.0684.
Acknowledgment This research is funded by State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau of China, Chinese Academy of Sciences & Ministry of Water Resources (funding number: 10501-226). Also, many thanks are acknowledged to Dr Wang Shanqin and Mr Li Shuo from College of Resources and Environment for
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their kind shear of the spectrometer and patient guidance on its operation procedure. Also, we are grateful to Mr Wu Wenqing and Mr. Wang Anping for their assistance during chemical experiment.
References [1] Zhou, Q.X.: Healthy Soil: Soil Health Quality and Safety of Agricultural Products. Science Press, Beijing (2005) [2] Cozzolino, D., Kwiatkowski, M.J., Parker, M., et al.: Prediction of phenolic compounds in red wine fermentations by visible and near infrared spectroscopy. Analytica Chimica Acta, 73–80 (2004) [3] Kim, S., Lim, Y.T., Soltesz, E.G., et al.: Near-infrared fluorescent type II quantum dots for sentinel lymph node mapping. In: Nature Biotechnology, pp. 93–97. Nature Publishing Group, New York (2004) [4] Loo, C., Lowery, A., Halas, N.J., et al.: Immunotargeted nanoshells for integrated cancer imaging and therapy. Amer Chemical Soc., Washington, DC, USA, pp. 709–711 (2005) [5] Lee, Y., Chung, H., Kim, N.: Spectral Range Optimization for the Near-Infrared Quantitative Analysis of Petrochemical and Petroleum Products: Naphtha and Gasoline. Applied Spectroscopy, 892–897 (2006) [6] Sun, D.W.: Infrared Spectroscopy for Food Quality Analysis and Control. Elsevier, San Diego (2009) [7] Dalal, R.C., Henry, R.J.: Simultaneous determination of moisture, organic carbon and total nitrogen by near-infrared reflectance spectrophotometry. In: Soil Sci. Soc. Am. J., The Soil Science Society of America, pp. 120–123 (1986) [8] Chang, C.W., Laird, A.: Near-infrared reflectance spectroscopic analysis of soil C and N. Soil Science, 110–116 (2002) [9] Reeves, J., Maccarty, G.: The potential of NIRS as a tool of spatial mapping of soil compositions. Journal of Near Infrared Spectroscopy, 153–158 (1999) [10] Wu, C.Y., Jacobson, A.R., Laba, M., et al.: Accounting for surface roughness effects in the near-infrared reflectance sensing of soils. Geoderma, 171–180 (2009a) [11] Wu, C.Y., Jacobson, A.R., Laba, M., et al.: Alleviating moisture content effects on the visible near-Infrared diffuse-reflectance sensing of soils. Soil Science, 456–465 (2009b) [12] Bao, Y.D., He, Y., Fang, H., et al.: Spectral Characterization and N Content Prediction of Soil with Different Particle Size and Moisture Content. In: Spectroscopy and Spectral Analysis, pp. 62–65. Peking University Press, Beijing (2007) [13] Sun, J.Y., Li, M.Z., Tang, N., et al.: Spectral characteristics and their correlation with soil parameters of black soil in Northeast China. In: Spectroscopy and Spectral Analysis, pp. 1502–1505. Peking University Press, Beijing (2007) [14] Michel, K., Terhoeven-Urselmans, T., Nitschke, R., et al.: Use of near- and mid-infrared spectroscopy to distinguish carbon and nitrogen originating from char and forest-floor material in soils. Journal of Plant Nutrition and Soil Science-Zeitschrift Fur Pflanzenernahrung Und Bodenkunde, 63–70 (2009) [15] Kennard, R.W., Stone, L.: Computer aided design of experiments. In: Technometrics, American Statistical Association, Alexandria, USA, pp. 137–148 (1969) [16] Whitfield, R.G., Gerger, M.E., et al.: Near-Infrared Spectrum Qualification via Mahalanobis Distance Determination. Applied Spectroscopy, 1204–1213 (1987)
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[17] Min, S.G., Li, N., Zhang, M.X.: Outlier diagnosis and calibration model optimization for near infrared spectroscopy analysis. In: Spectroscopy and Spectral Analysis, pp. 1205– 1209. Peking University Press, Beijing (2004) [18] Dean, R.B., Dixon, W.J.: Simplified Statistics for Small Numbers of Observations. Anal. Chem., 636–638 (1951) [19] Yan, Y.L.: Near Infrared Spectroscopy Fundamentals and Applications. China Light Industry Press, Beijing (2005)
Development and Application of Tennis Match Video Retrieval Technology in Multimedia Education Shehua Cao* School of P.E., East China Jiaotong University Nanchang, Jiangxi, P.R. China Tel.: +86-13507918839 [email protected]
Abstract. In order to improve the application effect of tennis match video in multimedia education, this paper puts forward a kind of method for retrieving the spectacular Rally scenes in tennis match video and classified the shots into Global View Shots and Non-Global View Shots. The Support Vector Machine (SVM) is for identifying the important types of audio in shots, applying the audio information in shots and setting up corresponding rules for retrieval. The results show that applying the retrieved spectacular Rally scenes in tennis match video in tennis multimedia education is line with most students' psychological situation and greatly popular with students. Keywords: Tennis Match Video, Visual Features, Movement Features, Audio Features.
1 Introduction With the emergence of many tennis match videos, the tennis match video retrieval technology has become a study topic urgently and strongly needed in application. The tennis match is very long, the proportion of the Non-play Shots is large and generally, the audience are usually interested in the match scenes or the spectacular Rally scenes in match, therefore, automatically retrieving the spectacular scenes from the tennis match video which the audience is interested in can save the audience's time for appreciation of match and make the audience be able to enjoy the match's spectacular Rally scenes in limited time. In addition, the spectacular Rally scenes extracted can also be applied in tennis multimedia education, which is of great research significance and application value in development of the retrieval technology for the spectacular Rally scenes in tennis match video.
2 Structure of Tennis Match Video The Rally shots, the players' close-up shots, the audiences' shots, the playback shots, the shot cuts and other shots which the audiences are interested in tennis match video *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 192–197, 2011. © IFIP International Federation for Information Processing 2011
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are with the predicable sequential structure. For the Play Shots in tennis match video, the number of play targets is fixed and the size of play targets can hardly be changed; the color of court accounts for the overwhelming majority of the video and the main color ratio is relatively high. The majority of Play Shots are Global View Shots, however, the Non-play Shots including the players' close-up shots and the audiences' shots are generally regarded as the Non-Global View Shots. The video's major audio events include the sound of ball-striking, the hurrahs of audiences, the sound of applause and the sound of the commentators. These sounds sometimes mix with each other, which even mix with the noise from the auditorium. But the audio information and the match proceeding state are closely related, like the ball-striking sound shows the Play state and after the Rally shots, there often come the sound of applause. It is thus evident that the retrieval of some audio events can help us analyze the tennis match video in a better manner. Through the analysis on the structure of tennis match video, we can find that the shot boundary detection is more suitable for the retrieval of spectacular Rally scenes in tennis match than the audio segmentation. For this reason, in the retrieval, we should firstly measure the similarity of shots based on the features of movement and major colors and design a two-category classifier, which classified the shots into the Global View Shots and Non-Global View Shots; and then apply the SVM for indentifying the meaningful audio events (like the sound of ball-striking and applause); apply the visual and audio features to set up the rules for heuristic procedures, detect the issues which the audiences are interested in the match video; finally set the spectacular degree model of the Rally scenes and arrange the spectacular degree in the from-high-to-low order.
3 Classification of Tennis Match Video Shots Due to the fact that the majority of Play Shots in tennis match video are Global View Shots, generally regarding the Serve scene as the Rally scene is not suitable[1], however, when classifying the shots into the Global View Shots and the Non-Global View Shots, we are not required assuming the color of court in advance, which is thus more suitable for the tennis match video shots. Apart from that, the classification of shots is not only required considering the similarity of low-level visual features, but people's perception and attention on movement. It should suit the outdoor tennis match video with relatively apparent changes of bright. 3.1 Classification Based on Features of Major Colors The tennis match video mainly includes four typical types of shots, namely, the Global View Shots, the Medium View Shots, the Close-up View Shots and the Audience View Shots. All Global View Shots have some common features of colors. The color of court in the Global View Shots accounts for the majority of the picture frame, making the main color ratio relatively high; apart from that, when comparing with the Non-Global View Shots, the colors of Global View Shots also distribute evenly. Therefore, the tennis match video can define the features of colors in Global View Shots through the description of key frames and the spatial distribution of major colors. We adopt the HSV color solid as the color models and classify the shots through comparing the key frames of each shot and referring to the similarity of key frames[2].
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3.2 Classification Based on Features of Movement The tennis match video always follows the attention-focus area and places it in the central part of the picture. Generally speaking, the attention-focus movement area and the non-attention-focus movement area have two differences in the spatial and time domain; in addition, the more intensified movement events are usually more attractive to audiences than the slow movement events[3]. Therefore, the conclusion of movement features should be based on the attention-focus movement model and the number and size of attention-focus movement area in the picture frame should be extracted according to the features and rules of tennis match[4]. When watching the tennis match, people's attention is usually focused on the players and the ball in the match shots, while when appreciating the close-up shots of players, people are interested in the players' some interesting behaviors. Through careful analysis, we have concluded two movement features of tennis match video: namely, (1) there are two attention-focus movement areas in the match shots (the players and tennis' movement areas); the attention-focus movement areas in close-up shots are usually some player's behaviors; for the audience shots, the number of attention-focus areas is uncertain usually. (2) The sizes of players and balls are seldom changed; while the sizes of the attention-focus movement areas in other Non-play Shots are not fixed. After the color and movement features of key frames are ascertained, we measure the similarity of two shots according to each key frame's movement and main color features and classify the shots into the Global View Shots and the Non-Global View Shots. When comparing with the Non-Global View Shots, the color features of Global View Shots include more colors of play court. Upon defining the main color ratio as the percentage of the main color pixel to the corresponding picture frame's all pixels, we conclude the main color ratio of the Global View Shots is higher.
4 Audio Identification in Tennis Match Video 4.1 Audio Type Identification Based on SVM[5] [6] Although most Global View Shots in tennis match video are Play Shots and the majority of Non-Global View Shots are Non-play Shots, we can not only depend on the visual features to correctly identify the Play Shots in tennis match video. The typical tennis match video has the special audio features. Applying the audio information of shots into the classifications of shots can detect the Play Shots in a more satisfied manner. The SVM boasts many advantages which is easy for training, needs less samples in training and can give consideration to the inaccuracies in study and the capacity of generalization. Therefore, the SVM is suitable for identifying the types of audio in tennis match video shots. The tennis match video's audio events include the sound of ball-striking, the sound of applause, the hurrahs of audiences, the sound of the commentators, the sound of referee and other unpredictable sounds from the site. During the whole play process, the commentator is almost commenting the match with a placid sound, even the match becomes brilliant, the commentator seldom sounds emotionally. For this reason, in tennis match video, there are not so much detection information for the sound of the commentator's comment. Furthermore, in tennis match, after each Rally shot, there will
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usually come the sound of applause. Comparatively speaking, the ratio of hurrahs is relatively low. Therefore, the sound of ball-striking and applause are the most significant audio events in the Rally match video, which can be directly used in differentiating Play Shots and Non-play Shots. For the reason that the sound of ball-striking and applause will not come at the same time, when applying the SVM in indentifying the audio events of the sound of ball-striking and applause, we should separately train a SVM for each audio part, namely, we could train the SVM with two kinds of audio which are separately for identifying the sound of ball-striking and applause. 4.2 Detection of Interested Events in Tennis Match Video In tennis match, the players can get points from counter attacks. The audiences are often interested in Rally shots. Apart from that, serving a ball is also an important way for players to get points. Therefore, in addition to the Rally shots, the serve shots are the events which the audiences are further interested in. The RePlay Shots are often the repeatedly played brilliant scenes in the match, which can be used in retrieval for spectacular scenes. For this reason, the detection of interested events covers the Rally shots, the Ace, the Missed Serve and the RePlay Shots. We can detect the shots in tennis match video according to the visual and audio features of these typical shots and set some heuristic procedures for detection of interested events, for instance, apply the differences of the number of ball-strikes in the shots to differentiate the Rally shots and the Serve shots; differentiate the Ace and the Missed Serve in the serve shots through identifying whether there is he sound of applause at the end of the shots; and differentiate the Play Shots and the Break Shots through identifying whether there is the sound of ball-striking in shots. Four rules can be worked out for the detection of interested events in the tennis match video shots: Rule 1: IF there is no sound of ball striking in one Global View Shot and even there is no sound of applause at the end of such shot, THEN this shot belongs to a Break Shot, ELSE it is a Play Shot. Rule 2: IF there is not only the sound of ball striking in one Global View Shot and even there is the sound of applause at the end of such shot, THEN this shot belongs to a Play Shot, ELSE it is a Break Shot. Rule 3: IF there is no sound of ball striking in one Global View Shot and even there is no sound of applause at the end of such shot, THEN this shot belongs to a Missed Serve Shot, ELSE judge whether the number of ball-striking sound is 1; if the number of ball-striking sound is 1, THEN this shot belongs to an Ace Shot, ELSE it is an Rally Shot. Rule 4: IF there is gradual change before and after the Break Shot, THEN this shot belongs to a Replay Shot, ELSE it is not a Replay Shot. 4.3 Retrieval and Sorting of Spectacular Rally Scenes in Tennis Match Video The Rally shots in tennis match video are the Play Shots and are also the shots which the audiences are interested at. When there's no shot cut in the Rally scenes, the Rally
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scene is made up of one Rally shot; therefore, the spectacular Rally scene is actually one spectacular Rally shot. The retrieval for the spectacular Rally scene is retrieving the brilliant shots from the Rally shots detected from the above section. In order to comment on the spectacular degree of the Rally shots, we set the spectacular degree model for the Rally shots according to the features and rules of the tennis match and the judge on the spectacular degree of the Rally shots by most people. When watching the match in tennis education, the students are usually more eager to see the long-time counter attach scenes. Therefore, the lasting time of one brilliant Rally shot is one of the important factors for evaluating the spectacular degree of the shot. Moreover, after one great Rally shot, the audiences usually give more enthusiastic applause. We can define the Rally spectacular degree model based on this law. Generally, after one great Rally shot, the tennis match video will Replay the brilliant parts of this shot from different visual angles. Therefore, the Rally live broadcast shot which is just after the Replay scene is one spectacular Rally shot, and the Replayed Rally shots are usually the most brilliant shots in the whole match video, which should be arranged in the forefront according to the from-high-to-low order of spectacular degree. The retrieval methods for the spectacular Rally scenes are as follows: (1) Judge whether the current Rally shot in the set of Rally shots is Replayed. If the answer is positive, mark this shot as RRally shot; (2) Take all RRally shots marked as spectacular Rally shots; (3) Calculate the RH values of all RRally shots marked and the Rally shots unmarked; (4) Set the threshold value TRally, if the RH of some unmarked Rally shots meet the standard of RH TRally, then this shot should be marked as spectacular Rally shot; (5) Arrange all the marked RRally shots and Rally shots according to the from-high-to-low order of the RH values, and arrange all RRally shots before the Rally shots.
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5 Application Effect of Spectacular Rally Scenes in Tennis Match Video In order to test the performance of the retrieval method for the spectacular Rally scenes in the tennis match video, we applied the same in the tennis match multimedia education in East China Jiaotong University(ECJTU). All the students having the lesson are the 2007-grade public sports tennis optional course students, who generally expressed that the video effect is very good and beneficial for learning the skills of tennis during the lessons. We sampled 90 students from the total of 260 students watching the tested scenes as the test targets and required them scoring the spectacular degree for the great Rally scenes, with the total score of 100. They respectively scored for the said scenes, making us receive the average score of 84.35, which is relatively satisfied.
6 Conclusion (1) The computational complexity obtained only through applying the visual features and adopting the hierarchical clustering algorithm in classifying the video shots is
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fairly considerable, which is not suitable for the retrieval of tennis match video. Applying the SVM audio identification technology and integrating the movement and visual features in video retrieval is convenient for extracting the size and number of movement areas in picture frame which people are interested at, as well as helpful for classifying the shots in tennis match video and enhance the application effect of the same. (2) Automatically extracting the reference key frames of Global View Shots based on the color and movement features and applying the similarity of the key frames and reference key frames of shots in classifying shots do not require the prior knowledge of the color of court. Such classification of shots is especially suitable for the tennis match video with the color of court not ascertained and the changes of bright of video relatively obvious. (3) When applying the SVM in identifying the important types of audio, we worked out four heuristic procedures for detection the interested events, which can improve the detection precision. The high identification rate of Rally events is extremely important for the retrieval of spectacular Rally scenes in the tennis match video. (4) The visual retrieval technology integrating the visual, movement and audio features can set the model for the spectacular Rally scenes in tennis match video. We can retrieve the same which is in line with most people's thoughts through the spectacular degree model of the Replayed Rally scenes and the spectacular Rally scenes.
References 1. Xing, L.Y., Ye, Q.X., Zhang, W.G.: A scheme for racquet sports video analysis with the combination of audio-visual information. In: Proceedings of International Conference on Visual Communications and Image Processing, vol. 5960 (2005) 2. Lin, T., Zhang, H.J., Feng, J., et al.: Analysis on Contents of Shots and Application of Contents of Shots in Video Retrieval. Journal of Software 13(8), 1577–1585 (2002) (in Chinese) 3. Ngo, C.-W., Ma, Y.-F., Zhang, H.-J.: Video Summarization and Scene Detection by Graph Modeling. IEEE Transactions on Circuits and Systems for Video Technology 15(2), 296–305 (2005) 4. Ma, Y.F., Zhang, H.J.: A model of motion attention for video. In: Proceeding of IEEE International Conference on Image Processing, Rochester, New York, September 2002, pp. 129–132 (2002) 5. Wu, F., Zhuang, Y., Pan, Y., et al.: Identification and Retrieval of Audio Samples Based on Incremental Learning of SVM. Journal of Computer Research and Development 40(7), 950–955 (2003) (in Chinese) 6. Zhuang, Y., Liu, J., Wu, F., Pan, Y., Zhang, Y.: Automatic Caption Location and Extraction Based on Support Vector Machine. Journal of Tsinghua University 14(8), 750–753 (2002) (in Chinese)
Fault Diagnosis of Roller Bearing Based on PCA and Multi-class Support Vector Machine Guifeng Jia, Shengfa Yuan∗, and Chengwen Tang College of Engineering, Huazhong Agricultural University, Wuhan 430070, P.R. China
Abstract. This paper discusses the fault features selection using principal component analysis and using multi-class support vector machine (MSVM) for bearing faults classification. The bearings vibration signal is obtained from experiment in accordance with the following conditions: normal bearing, bearing with inner race fault, bearing with outer race fault and bearings with balls fault. Statistical parameters of vibration signal such as mean, standard deviation, sample variance, kurtosis, skewness, etc, are processed with principal component analysis (PCA) for extracting the optimal features and reducing the dimension of original features. The multi-class classification algorithm of support vector machine (SVM), one against one strategy, is used for bearing multi-class fault diagnosis. The performance of the method proposed was high accurate and efficient. Keywords: fault diagnosis, principal component analysis, features selection, multi-class support vector machine.
1 Introduction Rolling bearing is one of the most widely used machinery components. It directly influences the operation of the whole machinery. Unexpected bearing failures can interrupt the production, cause unscheduled downtime and economic losses. So development of proper conditional monitoring and fault diagnosis procedure to prevent malfunctioning and failure of rolling bearings during operation is necessary. As a result, the fault diagnosis of rolling element bearings has been the subject of extensive research in recent years. To identify the most probable faults leading to failure, many methods are used for data collection, including vibration monitoring, thermal imaging, oil particle analysis, etc. Vibration analysis has been proved as the most effective and reliable method in diagnose. This article will apply the vibration signal to diagnose roller bearing faults. Then, the next step is signal processing. Modern signal processing methods can be divided into two categories, one is the direct signal analysis or decomposition, such as short-time fast Fourier transform (STFT), wavelet transform, principal component analysis (PCA), blind source separation, which are mainly used on the signal basis processing or preprocessing, for instance, the time-frequency domain analysis, feature extraction, noise reduction and others. The other is the processing based on intelligence algorithms, such as artificial ∗
Corresponding author. Tel.: +86027 61268360. E-mail: [email protected]
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 198–205, 2011. © IFIP International Federation for Information Processing 2011
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nerve networks (ANN), support vector machines (SVM), Bayes classification, decision tree, etc. The second class algorithms, artificial intelligence, are classifiers for fault diagnosis and decision. Two types of signal processing methods combined with organic is now the development trend of fault diagnosis field. This paper presented principal component analysis and multi-class support vector machines methods for signal processing and fault recognition. The signal processing scheme as the follows; (1) Calculating the parameters which discussed above for each sample to obtained an observed X. (2) Selection principal features form the original parameters by principal component analysis method. (3) Fault recognition, optimized samples would be training and classify applied multi-class SVM. The procedure of experiment scheme was illustrated in fig.1.
Vibration data collection form
Design multi-class support
operating roller bearing
vector machine and training using the fault features
Parameters choose and calculation
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extract/optimum
utilizing principal component analysis
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2 The algorithm analysis
Fig. 1. Experiment scheme procedure
1.1 Signal Data Parameters The formula 1-3 illustrated that frequency is principal parameters used in bearing diagnose. 1 d D (1) f b = f [(1 − ) 2 cos 2 a ] 2 D d
fi =
1 d f [(1 − cos a )]Z 2 D
(2)
1 d (3) f [(1 + cos a )]Z 2 D fb, fi and fo are respectively outer race fault frequency, Inner race fault frequency, Balls spin frequency. Therefore, to accurately reflect the bearing fault type, it needs extract information form time domain and frequency domain. Consequently, the parameters fo =
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applied in experiment were mean, standard deviation, sample variance, kurtosis, and skewness, peak-peak value and frequency [1]. Some complicated parameters and formulas were explained as following. (1) Peak-peak value
Vp-p = max(yi )-min(y i )
(4)
(2) Mean
Vm =
1 N
1
∑y
(5)
i
i =1
(3) Standard deviation Standard deviation is a measure of the efficient energy or power content of the vibration signal and clearly indicates deterioration in the bearing condition. n
SD =
n
n ∑ yi 2 − (∑ yi )2 i =1
i =1
n(n − 1)
(6)
(4) Sample variance Sample variance is a measure of the amount of variation within the values of that variable, taking account of all possible values and their probabilities or weightings.
SV =
n
n
i =1
i =1
n∑ yi 2 − (∑ yi )2
(7)
n(n − 1)
(5) Kurtosis Kurtosis coefficient of the formation of substantial value that fault pulse the probability, kurtosis coefficient of the impulse response amplitude of the 4th power to determine the basis for improved signal to noise ratio, accuracy greatly enhanced when the bearing surface of the work of fatigue failure, The impact of face defect pulse, the greater the failure, the greater the impulse response amplitude, the more obvious faults. n
∑(y -μ) 4
Kurtosis =
i =1
i
Nσ 4
(8)
(6) Skewness Skewness is a measure of the degree of asymmetry of a distribution. If the left tail is more pronounced than the right tail, the function is said to have negative skewness. If the reverse is true, it has positive skewness. If the two are equal, it has zero skewness.
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Skewness =
1 n yi − μ 3 ∑( σ ) N i =1
201
(9)
(7) Frequency1 In the signal frequent domain, frequency is principal parameter for signal analysis, which contains the bearing fault frequent information. Frequency1 was the frequency which was corresponds with the maximum amplitudes in power spectrum. Consequently, the vibration signal needed Fast Fourier Transform (FFT) in the first to obtain power spectrum. 1.2 Principal Component Analysis Principal component analysis (PCA) involves a mathematical procedure that transforms a number of possibly correlated variables into a smaller number of uncorrelated variables called principal components. The first principal component accounts for as much of the variability in the data as possible, and each succeeding component accounts for as much of the remaining variability as possible. The performance of PCA is efficient for dimensionality reduction, which can reduce the complexity of signal processing [2] [3]. The article presented the PCA method for roll bearing vibration signal processing. The original statistical characteristics discussed in chapter 1.1. The steps of PCA as follows: (1) (2) (3) (4) (5)
Standardize the sample observed matrix X to get standardized X*. Calculate the covariance matrix R. Calculate the eigenvectors and eigenvalues of the covariance matrix R. Choosing components and forming a feature vector. Deriving the new data set.
1.3 Multi-class SVM Algorithms Support vector machine (SVM), an excellent algorithm used for classification and regression, was relatively new computational learning method based on the statistical learning theory, which developed by Vapnik. SVM classifier is better than ANN because of the principle of risk minimization. In ANN traditional empirical risk minimization was used on training data set to minimize the error. But in SVM, structural risk minimization (SRM) was used to minimize an upper bound on the expected risk. The SRM structure makes SVM good performance for reliable and accurate. Moreover, the algorithm sample requirement is small-scale. Therefore, SVM is very suitable for bearing fault diagnose. This article does not discuss the mathematical theory, it can be found in related books or papers conveniently. With the passage of time, SVM has been successfully applied to several filed such as detection, recognition, prediction, regression, fault diagnose, etc. The original SVM algorithm is a binary classification where the class labels can take only two values:1 and -1, but in fact, the classify problems usually have more than two classes, take the bearing fault diagnose for example, there are inner race fault, outer
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race fault, balls fault and retainer fault [4]. Consequently, the multi-class SVM classification strategy will be utilizing for bearing multi-fault diagnoses. There have three strategy of multi-class SVM: one against one (OAO), one against all (OAA) and direct acyclic graph (DAG). This article applied OAO binary SVM to diagnose the fault types. One-against-one classifiers structure has n*(n-1)/2 Classifiers and it employs the method of majority voting scheme to combine classifier and to evaluate classified result. Its principle was illustrated by formula 10-12 [5] [6] [7].
( )
Minimize:
1 ij T ij w w + C ∑ ξtij 2 t
(10)
Subject to:
(w ) Φ(x ) + b
≥ 1 − ξ tij
(11)
if
yt = i (wij ) Φ ( xt ) + bij ≤ 1 − ξtij ,
(12)
if
yt = j ξ tij ≥ 0
ij T
t
ij
T
2 Experiment Setup 2.1 Bearing Fault Data The time series vibration signals were obtained from the Case Western Reserve University Bearing Data Center for the following conditions: normal bearing, bearing with inner race fault, bearing with outer race fault and balls fault, and collected at 12,000 samples per second. The type of bearing used in experiment was 6205-2RS JEM SKF, deep groove ball bearing. The signal of each fault was displayed in fig. 2.
Fig. 2. Fault bearing signal
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2.2 Features Selection Using Principal Component Analysis The original statistical features presented in chapter 1.1 were peak-peak value, mean, standard deviation, sample variance, skewness, kurtosis, frequency1. Experiment’s scheme as follows: extract fifty samples from each fault signal and the length of each sample was 1,200 points, just 0.1 second. Consequently, it obtained 150 samples totally. Calculating the original parameters for each sample signal using the formula 4 to 9 achieve an observed matrix X. Then, processed observed matrix according to the steps of principal component analysis,
X* =
X-X p
(13)
S
X* stand for the standardized matrix, Xp was the mean of vibration signal and S was standard deviation. Firstly, the observed matrix X needs standardization according to formula 13.Then, calculated the correlation coefficient matrix R and its eigenvector, eigenvalues. The results of principal component analysis were presented in table 1. According to the table 1, it can learn that there were four principal components, named Prin1, Prin2, Prin3 and Prin4, selected from the original parameters. The Accumulative Contribution Ratio of principal components was 0.9883, practically contained the information of original features. Table 1. Principal component loading matrix L Principal component loading x1 x2 x3 x4 x5 x6 x7
Prin1
Prin2
Prin3 -0.4170 -0.0649 -0.0383 -0.3271 -0.5362 -0.2230 0.2402
Prin4
0.4838 -0.9329 -0.9315 0.8877 0.0548 -0.9214 0.9149
-0.7661 -0.3373 -0.3276 -0.3105 0.8350 -0.1459 -0.1680
0.0424 -0.0407 0.0883 0.0035 -0.0346 -0.2597 -0.2368
Contribution Ratio
0.6356
0.2359 0.0974 0.0194
Accumulative Contribution Ratio
0.6356
0.8715 0.9688 0.9883
The last step was calculating ultimate result, principal component matrix Z, which was contained 98.8 percentage information of original parameters. Based on formula 14, matrix Z was calculated by left multiplication loading matrix L.
Z = X* * L
(14)
Finally, principal component analysis was pre-processing stage for multi-class SVM.
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2.3 Data Process and Fault Diagnose Utilizing Multi-class SVM Based on the characteristics of three bearing faults types, OAO strategic multi-class SVM algorithm was developed in this identification experiment. In this part, four parameters, selected by principal component analysis, were used for multi-class SVM, and every type fault contained 60 samples. Therefore, there were 180 samples used in training stage. Z= [Prin1 Prin2 Prin3 Prin4] T
(15)
Matrix Z was 180×4, contain the train information. Table 2 presented the setting of SVM training. Table 2. Training parameters of MCSVM Type of kernel functions Number of features used Number of samples
Liner 4 180
Table 3 was the recognized result of multi-class SVM, which illustrated that the diagnostic correct accuracy of inner fault, outer fault and bolls fault separately were 85.7%, 98.9% and 96.9%. The number of predicted samples was 294 and 276 samples recognized exactly. Correct accuracy in total was 97.3%.The result showed that the OAO multi-class SVM was proper forbearing fault diagnose. Table 3. Diagnosed result of MCSVM Fault types
Number of correct classified samples
Number of incorrect classified samples
Predict Accuracy
Inner race fault
98
14
85.7%
Outer race fault
98
1
98.9%
Bolls fault
98
3
96.9%
3 Conclusions The paper presented the principal component analysis used in bearing fault features selection for reducing dimensions and the performance was efficient. As a result, obtained four principal components and its Accumulative Contribution Ratio nearly contain all original parameters information. Fault recognition using multi-class SVM, the correct ratio of classification totally is impressive. It is observed that the recognition performance of multi-class SVM technology is enhanced by PCA per-processing stage.
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References 1. Heng, R.B.W., Nor, M.J.M.: Statistical Analysis of Sound and Vibration Signals for Monitoring Rolling Element Bearing Condition. Applied Acrostics 53, 211–226 (1998) 2. Nimityongskul, S., Kammer, D.C.: Frequency domain model reduction based on principal component analysis. Mechanical Systems and Signal Processing 24, 41–51 (2010) 3. Serviere, C., Fabry, P.: Principal component analysis and blind source separation of modulated sources for electro-mechanical systems diagnostic. Mechanical Systems and Signal Processing 19, 1293–1311 (2005) 4. Sugumaran, V., Sabareesh, G.R., Ramachandran, K.I.: Fault diagnostics of roller bearing using kernel based neighborhood score multi-class support vector machine. Expert System With Application 34, 3090–3098 (2008) 5. Abbasiona, S., Rafsanjani, A., Farshidianfar, A., Irani, N.: Rolling element bearings multi-fault classification based on the wavelet denoising and support vector machine. Mechanical System and Signal Processing 21, 2933–2945 (2007) 6. Debnath, R., Takahidel, N., Takahashi, H.: A decision based one-against-one method for multi-class support vector machine. Pattern Analysis & Applications 7, 164–175 (2004) 7. Manikandan, J., Venkataramani, B.: Study and evaluation of a multi-class SVM classifier using diminishing learning technique. Neurocomputing 73, 1676–1685 (2010)
Health Status Identification of Connecting Rod Bearing Based on Support Vector Machine Yongbin Liu1, Qingbo He1, Ping Zhang1, Zhongkui Zhu2, and Fanrang Kong1 1 Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230027, China 2 School of Urban Rail Transportation, Soochow University, Suzhou, Jiangsu 215021, China [email protected]
Abstract. Connecting rod bearing (CRB) is an important component which joins the reciprocating and rotating movements together in the internal combustion engine (ICE). It is very difficult to identify health status of CRB because of variable working process, complicated excitation and distribution sources, and lack of fault samples. Support vector machine (SVM), which has excellent capability in small data case, was introduced to identify the health status of CRB. In this paper, faults of the CRB were simulated in an ICE with the type of EQ6100. Vibration features were extracted from vibration signals acquired from the shell of ICE. And a SVM multi-classifier was designed to identify health status of CRB by using the radial basis kernel function. Experimental results indicated that the presented fault diagnosis method could effectively recognize different conditions of CRB. Keywords: Support Vector Machine, Internal Combustion Engine, Connecting Rod Bearing, Fault Diagnosis.
1 Introduction Internal combustion engine (ICE), a complicated mechanical system, is composed of different parts, in which connecting rod bearing (CRB) is an important one joining the reciprocating and rotating movements together. It is difficult to identify the health status of CRB for several reasons, such as variable working process, complicated excitation and distribution sources, and lack of fault samples [1,2]. One crucial task in CRB fault diagnosis is the feature classification based on vibration signal. For this problem, methods based data learning have been investigated for fault diagnosis, such as neural network [3], Bayesian classification [4], etc. However, the vibration samples that represent the condition are difficult to collect in practice, which make the methods mentioned above are limited to being used. Therefore, it is critical to select an excellent classifier for reliable fault diagnosis. Support vector machine (SVM), a machine learning method based on the statistical learning theory, was presented by Vapnik et al. [5-7]. The SVM implements the structural risk minimization principle which leads to the preferable generalization capability. Kernel function is used to map a sample input space into a high-dimensional D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 206–214, 2011. © IFIP International Federation for Information Processing 2011
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feature space through some nonlinear mapping. With SVMs, nonlinear dependence between factors and objects can be described. Because of the excellent capability in small data case and in limiting over learning, SVM has been used in many applications, such as pattern recognition [8], regressive analysis [7], etc. Especially, it shows advantages in fault diagnosis as described by the referred studies [9-12]. In this paper, we address extraction vibration signal features of connecting rod bearing, and health status identification of connecting rod bearing using the SVM. The organization of this paper is arranged as follows. The theoretical background of the proposed method is introduced in Section 2. The fearture extraction method and feature analysis are described in Section 3. The application example is presented in Section 4. Finally, conclusions are drawn in Section 5.
2 Support Vector Machine SVM is a machine learning tool that is especially fit for classification in small-sample cases due to its good generalization capability. The basic idea of SVM for pattern recognition is to map data to a high-dimensional space by a nonlinear mapping, and find an optimum linear separating hyperplane with the maximal margin in this higherdimensional space [6,7]. However, the calculation complexity does not increase almost in the high-dimensional space as a kernel function is used. “one-against-one” and “oneagainst-all” are the most commonly used methods of SVM classifier [8]. Multiclassification can be obtained by combining several binary classifiers. Considering the need of recognizing multiple statuses in fault diagnosis of ICE, one-against-all multiclass classifier is constructed in this paper and described in detail as follows [5]. Given a training set ( xi , yi ) , i = 1, 2," , l , where l is the number of samples, xi ∈ Rn
is input data and yi = {−1, +1} is output class data. Finding an optimum separating hyperplane is equivalent to solving the following quadratic programming problem: min 1 wT w + C
w, b,ξ
2
(
l
∑ξ
i
(1)
i =1
)
⎧⎪ yi wT Φ( xi ) + b ≥ 1 − ξi , S.t. ⎨ ⎪⎩ ξi ≥ 0. where w ∈ R n and b ∈ R are the weighting factors, ξi is the slack variable, and C is the penalty parameter. Input vector
x = ( x1 , x2 ,", xl ) in original space can be
mapped to high-dimensional feature space using the function Φ ( ⋅) . In feature space, optimum separating hyperplane can be found by maximizing the margin 2/||w||. The decision function can be finally written as:
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⎛ sgn ⎜ ⎜ ⎝
⎞ Φ(x j ) + b ⎟ ⎟ ⎠
l
∑ y α Φ(x ) i
i
T
i
i =1
(2)
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∑
where the project function Φ ( x i ) could be conveniently replaced by a kernel function K ( xi , x j ) = Φ ( xi ) ⋅ Φ ( x j ) . Then the decision function can be rewritten as:
⎛ sgn ⎜ ⎝
l
∑ y α K (x , x i
i
i
i =1
j
⎞ )+b⎟ ⎠
(3)
There are several commonly used kernel functions: linear function, polynomial function, and radial basis function (RBF). The radial basis function was described as follows:
(
K ( x i , x j ) = exp -γ xi - x j
2
)
(4)
where γ > 0 , and γ is the kernel parameter. For classable k-class statuses of connecting rod bearing of internal combustion engine, a multi-class classifier can be constructed to identify health statuses of CRB using k classifiers, each of which is trained by binary-class data as above. To identify the health status of CRB, the feature vectors of a sample are firstly sent into the classifier 1. If the output of the decision function is 1, the sample will belong to class 1 and the process of classification is over. Otherwise, the feature vectors are secondly sent into the classifier 2. Then the following process does the same as above until the classification is finished. If the final output is -1, the sample will not be included in the k class statuses.
3 Signal Acquisition and Feature Analysis 3.1 Signal Acquisition
Experiments were conducted on an internal combustion engine with the EQ6100 type. Faults were set to simulate abnormal statuses of connecting rod bearing in advance. Four wear conditions including normal wear, slight wear, medium wear and severe wear were set on the fifth cylinder of the ICE which has total six cylinders. As listed in Table 1, the clearances between bearing and axle neck corresponding to four statuses were set using plug gauges except for normal condition. In the experiments, each time only one fault was set in order to make the simulated fault as real as possible and reduce disturbances as much as possible. Vibration signals were acquired by B&K4384 model accelerometer mounted on the shell of the fifth cylinder of the ICE. Then, the signals were amplified by B&K2635 model charge amplifier and saved in computer through the data acquisition card. The rotating speed of the engine was kept at 1000 rpm without loads, and the sampling frequency was set to be 10 kHz.
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Table 1. Faults setting Status
Clearance(mm)
Normal Wear
0.04-0.098
Slight Wear
0.15
Medium Wear
0.30
Severe Wear
0.50
3.2 Feature Analysis of Vibration Signals
Due to the complex and stochastic nature of internal combustion engine, there are many excitation sources and complex interferences in its working process, such as transformation between rotating and reciprocating movements, ignitions and explosions, some unbalance impacts, differences and interferences in different working cycles, etc. The connecting rod bearing is a critical component which joins the rotating and reciprocating movements. The vibration signals of CRB are modulated and attenuated by multiple parts before being transferred to the sensor. Therefore, the measured vibration signals include lots of disturbance noise. To make the signal analysis results equitable, the measured signal firstly needs to be preprocessed to minimize the noise caused by the sensor itself and machine working environment. This can be done based upon the mean-variance standardization method as described below. Given the measured vibration signal is one-dimensional data {x1 , x2 ," , xn } , where n is the length of sample. The mean of the sample can be written as follows: 1 n x = ∑ xi (5) n i =1 And the variance of the sample can be written as:
(
1 n ∑ xi − x n − 1 i =1 Then the sample is standardized as follows:
σ =
xi' =
xi − x
σ
)
2
(6)
(7)
After mean-variance standardized, vibration signals will have zero mean and unit variance. In general, it is difficult to classify the vibration signals of CRB into different statuses using time-domain features only. The features in frequency-domain can also reflect different statuses of CRB to a certain extent. For example, the energy distribution in some typical frequency band could reflect CRB condition. Therefore, vibration features in both time-domain and frequency-domain were extracted to identify the health status of CRB comprehensively. These features include: Time-Domain Features: absolute mean, maximum peak, the root mean square, the variance, peak-peak, the kurtosis, the skewness, the square root, the crest factor, the shape factor, the kurtosis factor, the impulse factor, and the tolerance factor; Frequency-Domain Features: average frequency, stabilization factor of spectrum peak, as well as five spectral energy values on five equally divided frequency bands.
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The total 20 features described above, which calculated according to the reference [13], were extracted from vibration signals of internal combustion engine. Thus, the health status of connecting rod bearing could be diagnosed comprehensively by a combination of these features. Features as illustrated in Fig.1 were extracted from vibration signals of connecting rod bearing with four conditions (normal wear, slight wear, medium wear and severe wear). As shown in Fig.1, the horizontal ordinate represents sample numbers, in which 50 samples for each type of signal are analyzed. It can be seen that these features are different from each other. The 20 features represent different physical signification respectively and the sensitivity and regularity of each feature is different. It is difficult to find which feature is more sensitive and stable intuitively than others in representing the status of CRB. In order to avoid the scale effect of the features and make all the features hold in a uniform scale, features were also preprocessed with the mean-variance standardization method.
4 SVM for Fault Diagnosis of CRB After being preprocessed by the mean-variance standardization method, typical vibration signals of the CRB are shown in Fig. 2 with four wear conditions including normal wear (denoted as C1), slight wear (denoted as C2), medium wear (denoted as C3) and severe wear (denoted as C4). As seen from Fig. 2, it is difficult to find the difference among the four conditions. The corresponding frequency spectra are illustrated in Fig.3, from which we can see that the maximum spectral energy all locate around 1400Hz on four conditions. The energy is distributed widely on the spectrum except
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the severe wear condition, the energy of which is concentrated at 1400 Hz. From the frequency-domain, it is also difficult to see intuitively the difference among the four conditions. A set of data which is comprised of fifty vibration signals were acquired from each condition and twenty vibration features are extracted from each signal. Therefore, we can construct a 50×20 vibration feature matrix for each condition. Fig. 1 illustrates the 20 vibration features on four conditions respectively. From Fig.1, it is difficult to find which feature is more sensitive and more stable than others in representing the status of connecting rod bearing. We selected the fore-half of the feature matrix of each condition, i.e., a 25×20 sub-matrix, to train the SVM classifier and used the left half of the matrix for testing. It is well known that the classification performance of the SVM depends on what kernel function is used to a certain degree. In the training, we compared linear kernel function, polynomial kernel function and radial basis kernel function. The training results using the three kernel functions are illustrated in Table 2, where the training time is denoted by TT, and the correct recognition rate is denoted by CRR. The parameters of the kernel functions are taken as: power index d=3 for the polynomial kernel function and γ = 2.17 for the radial basis function. It can be seen from Table 2 that recognition accuracy rates are almost the same when using all three kernel functions. But the training time of SVM classifier based on radial basis function is much less than that based on the other two functions. Meanwhile, the radial basis kernel function has a less parameter advantage over the polynomial one. The complexity of SVM would be affected directly by the numbers of parameter. Therefore, in this paper, we constructed the SVM classifier using radial basis kernel function to identify the status of connecting rod bearing. 10 C1
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The essential problem of machine condition monitoring and fault diagnosis is pattern recognition [9]. The correct feature recognition is the basis of identifying the status of machine. The performance of the classifier will directly affect the fault diagnosis of machine. Therefore, the three-layer back propagation neural network (BPNN) and k-nearest neighbor classification (KNN) were used to compare with one-against-all SVM multi-classifier. In the training process of the BPNN, the transfer functions were chosen as log-sigmoid function and tan-sigmoid function respectively. Training times was set to 200, and network performance object was set to 0.001. Euclidean distance and one nearest neighbor were used in the KNN classification. When training the SVM classifier, the least square SVM algorithm was used. Radial basis function was selected as the kernel function with the kernel parameter γ being equal to 2.17. Table 3 shows the training time and correct recognition rate of the four statuses by using 3-layer BPNN, KNN and SVM classifier respectively. As seen from table 3, the correct recognition rates are almost the same on normal wear condition using BP neural network and SVM classifier. However, on other three conditions, the correct recognition rate of SVM classifier is higher than the rate of BPNN in evidence. Moreover, the training time of BPNN is far greater than SVM classifier used. Although the computer time of KNN is similar to SVM, its correct recognition rate is much lower than that of the other two methods. The results illustrates that the SVM is effective to identify the health status of connecting rod bearing of ICE.
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Table 2. Diagnosis results by SVM with different kernel functions Linear Function TT CRR
Status of CRB
Polynomial Function TT CRR
Radial Basis Function TT CRR
C1
0.849s
100%
0.822s
99.4%
0.632s
99.3%
C2
0.799s
98.3%
0.843s
98.3%
0.527s
97.8%
C3
0.833s
99.5%
0.830s
99.1%
0.590s
98.5%
C4
1.486s
98.2%
0.849s
97.5%
0.591s
96.7%
Table 3. Comparision of BPNN, KNN and SVM results KNN
BPNN
SVM
Status of CRB
TT
CRR
TT
CRR
TT
CRR
C1
0.921s
71.1%
7.023s
98.5%
0.632s
99.3%
C2
0.824s
73.3%
7.316s
90.7%
0.527s
97.8%
C3
0.989s
77.3%
6.088s
90.8%
0.590s
98.5%
C4
0.709s
79.5%
8.487s
90.4%
0.591s
96.7%
5 Conclusions This paper addresses on identification of the CRB health status of the ICE by using limited samples. By comparing, the SVM multi-classifier based on radial basis kernel function is chosen for identifying the health status of CRB. Furthermore, considering the training time and correct recognition rate in comparison with the BP neural networks, the SVM classifier based on statistical learning theory is especially fit for fault diagnosis in small-sample cases. The results in this study validate the effectiveness of applying SVM multiclassifier to identifying the health status of connecting rod bearing. This illustrated that the SVM has great practical value and provide an efficient method for intelligent diagnosis of ICE.
Acknowledgements This work was partially supported by the National Natural Science Foundation of China (No.50905021) and by the Fundamental Research Funds for the Central Universities in China.
References 1. Wu, Z.-Y., Yuan, H.-Q.: Research on Fault Diagnosis of Engine by Ant Colony Support Vector Machine. Journal of Vibration and Shock 28(3), 83–86 (2009) 2. Jia, J., Kong, F., Liu, Y., et al.: Noise Diagnosis Research Based on Wavelet Packet and Fuzzy C-clusters about Connecting Rod Bearing Fault. Transactions of the Chinese Society for Agricultural Machinery 36(6), 87–91 (2005)
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3. Rao, K.S.R., Yahya, M.A.: Neural Networks Applied for Fault Diagnosis of AC Motors. In: Proceedings of International Symposium on Information Technology, vol. 1-4, pp. 2607–2612 (2008) 4. Sahin, F., Yavuz, M.C., et al.: Fault Diagnosis for Airplane Engines Using Bayesian Networks and Distributed Particle Swarm Optimization. Parallel Computing 33(2), 124–143 (2007) 5. Vapnik, V.N.: The Nature of Statistical Learning Theory. Springer, New York (1995) 6. Vapnik, V.N.: Statistical Learning Theory. Wiley, New York (1998) 7. Vapnik, V., Golowich, S., et al.: Support Vector Method for Function Approximation Regression, Estimation, and Signal Processing. In: Advances in Neural Information Processing Systems, vol. 9, pp. 281–287 (1996) 8. Liu, Y., You, Z., et al.: A Novel And Quick SVM-Based Multi-Class Classifier. Pattern Recognition 39, 2258–2264 (2006) 9. Hu, Q., He, Z., et al.: Fault Diagnosis of Rotating Machinery Based on Improved Wavelet Package Transform and SVMs Ensemble. Mechanical Systems and Signal Processing 21, 688–705 (2007) 10. Yuan, S.-F., Chu, F.-L.: Support Vector Machines and Its Applications in Machine Fault Diagnosis. Journal of Vibration and Shock 26, 29–35 (2007) 11. Yuan, S.-F., Chu, F.-L.: Support Vector Machines-Based Fault Diagnosis for Turbo-pump Rotor. In: Mechanical Systems and Signal Processing, vol. 20, pp. 939–952 (2006) 12. Yang, Y., Yu, D., et al.: A Fault Diagnosis Approach for Roller Bearing Based on IMF Envelope Spectrum and SVM. Measurement 40, 943–950 (2007) 13. Chen, K., Li, C.: Machine Condition Monitoring and Fault Diagnosis Technology. Beijing Science and Technology Press, Beijing (1991)
Investigation of the Methods for Tool Wear On-Line Monitoring during the Cutting Process Hongjiang Chen School of Mechanical and Electrical Engineering, Jiangxi Science & Technology Normal University
Abstract. This paper is well targeted in researching several researches of various tool wear monitoring methods in domestic and foreign. Five important tool wear methods are deeply investigated and described in detail. Through comparing the advantages and disadvantages of each monitoring method according to practical application, and draw a conclusion that the based on multi-sensors method is considered as the main direction of the development of tool wear monitoring in the near future, which would be a great significance for improving the utilization of machine and reducing the economic losses due to the tool wear. Keywords: tool wear, monitoring method, cutting process.
1 Introduction Tool wear is a common phenomenon in cutting process, which directly affects machine-finishing precision, the efficiency and the economic efficiency. Investigation of tool wear can greatly improve the machine-finishing efficiency, and reduce the processing cost, and have enormous economic effect. Industry statistics indicated that tool failure was the primary factor caused the machine breakdown, which accounted for the shutdown of the 1/5 to 1/3 during the total downtime of the CNC machine tool [1]. Studies showed that if CNC machine tool is equipped with monitoring and detection system, it can reduce 75% the downtime, and enhance productivity 10% ~ 60%, and even raise machine utilization above 50% [2]. American Kennamtal Corporation's research indicated that if the CNC system is equipped with tool monitoring system, it can save up to 30% processing fee [3]. Therefore, it is necessary to research the process in tool condition monitoring technology to prevent the work piece scrap caused by tool failure, and to ensure the CNC machine works with trouble-free operation as long as possible. Tool wear monitoring methods generally can be divided into direct measurement methods and indirect measurement methods [4-6]. The direct measurement methods include discharge current measurement, optical fiber measurement, micro-structure of coating method, resistance measurement method, ray measurement method, as well as computer image processing method. While the indirect measurement methods use the physical quantities, which are mainly related to the cutting process, such as cutting force, torque, cutting italics machine, work piece geometry, chip shape, noise or vibration intensity. The more popular methods acoustic emission monitoring method and multi-sensors are based on monitoring method [7]. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 215–220, 2011. © IFIP International Federation for Information Processing 2011
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The direct method of tool condition monitoring has two obvious shortcomings. On the one hand, it needs to stop CNC machine to detect the tool state that occupancies production time. On the other hand, it can not check the sudden damages during the cutting process, which is subject to a certain restrictions on its use [8]. Therefore, the indirect method has become the mainstream of academics who have studied in domestic and foreign.
2 The Indirect Method of the Tool Condition Monitoring Tool condition monitoring techniques are generally consist of the sensor signal acquisition, signal processing and feature extraction and pattern recognition device. The basic structure of the tool condition monitoring system was presented in Figure 1. Cutting process Singles input
Sensors send singles
Results recognition
Extraction signals and processing characteristic
State recognition
Fig. 1. The basic structure of the tool condition monitoring system
2.1 Cutting Force Monitoring Method of the Tool Status Extensive researches showed that the tool wear of cutting force has a direct inner contact during the cutting process, moreover, the cutting force signals can be accessed through the ordinary resistance strain gauges, or piezoelectric sensors. And the cutting force in general with the increase of tool wear. S. Jetly’s experiment results indicated that the feed force is more sensitive than the main cutting force to the tool wear in the turning process [9]. However, Shaohua’s [10] research concluded that the main cutting force can reflect the most cutting tool's attrition rate. North China Electric Power University, Kangshi li [11], who designed the system of LABVIEW-based cutting force data acquisition and storage, and its application procedure including the data acquisition and memory of the three cutting force, the cutting force profile demonstration and feedback, the experimental data analysis statistical analysis (error analysis, unusual data processing and so on), and the cutting temperature empirical formula foundation, etc. Due to the complexity of the cutting process, many factors affect the cutting force, so it is very difficult to establish a precise and perfect cutting force model. Even if has established a perfect cutting force model, it’s difficult to distinguish between the changes of cutting parameters caused by the changes of the cutting force component or by the tool breakage ,or by the wear of the cutting pitch changes. In addition, when install the measuring devices required for re-equipping the machine structure, which caused the adjustment and maintenance is inconvenience. Therefore, we can draw the
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conclusion that this method is not suitable for promotion in actual production, especially in some poor condition factories. 2.2 Cutting Noise Monitoring Method of the Tool Condition The measured sound signals contain much information about the state cutting in cutting process, and thus can monitor the tool's state by taking advantage of the sound signals. A. B. Sadat [11], who found that the friction noise’s sound level between the tool and the workpiece in the 0.73~3.5 kHz frequency domain through many experiments by his experimental staff. The blunt tool is approximately 15 dB higher than the new blade. In the initial wear, the noise sound level increases in an obvious rise, and then stabilized. When the cutting velocity increases, the noise sound level decreased, while the tool cantilever increases, the noise sound level enhanced. L. C. Lee [12] found that in most of the work piece material combinations and operating conditions, there is a cutting noise of the characteristic frequency near 4-6 kHz frequency, its sound pressure level has a very good correlation with the tool wear. Before the rapid wear and tear, the sound pressure level assumes the declining trend. At present, the cutting noise monitoring method is rarely used in monitoring system. One of the most important reasons is that the voice detection is hard to implement in actual processing workshop, because of the workshop ambient noise is usually about 90dB. In addition, the real-time signal processing technology, as well as feature extraction method has yet to be further studied. So, the method almost has no application in practice. 2.3 Acoustic Emission Monitoring Method of the Tool Status AE (acoustic emission) technology is a new method for tool wear monitoring in recent years. The AE signal has the transient state and randomness, belongs to the nonsteady random signal. We have done many experiments studies in laboratory, and have discovered that in the metal-cutting process has rich information of AE. The socalled AE phenomenon means that when the solid occurs in deformation or fracture, it emits elastic wave, therefore, AE signal is a mechanical wave in nature, with a wave of basic characteristics of volatility and decaying. In metal-cutting process, the following phenomena can generated AE signals, such as the tool flank of the friction and chip impact, breaking, as well as the plastic deformation of shear zone, the friction of the rake face’s second area and so on [14]. When the cutting tool occurs in wear and damage, the acoustic emission signals will be changed. During the monitoring and testing processes, generally use piezoelectric sensors to pick up signals and approach to the cutting tool as far as possible. At present, the characteristics of acoustic emission monitoring have the RMS value energy analysis, ring count, amplitude distribution and spectral analysis and so on. T. Blum studied the changes in cutting conditions affect the RMS of acoustic emission signals, the count rate, and discovered that the RMS value of acoustic emission signals are increased with the extent of the flank wear of cutting tool, and also increased with the cutting parameters enlarged, there exists a linearly increasing relationship between the count rate and the cutting speed, the total acoustic emission event rate is increased with the feed rate decreased [l5]. However, the overall incidence of acoustic emission is increased alone with the feed rate decreased.
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According to the above analyzed, we can draw the conclusion that the advantages of the acoustic emission monitoring tool wear states as follows: firstly, the acoustic emission frequency range is much higher than the mechanical vibration and environmental noise. So, the high-pass filter is very easy to obtain the non-disturbance signals. Secondly, the sensor of receiving acoustic emission piezoelectric crystal can be easily installed in the tools without affecting the process. Thirdly, AE signals can avoid the worst impact zone that the machine processing of low-frequency noise, affected by vibration and sound-frequency noise is very little, a higher signal to noise ratio in the high frequency area, to facilitate the signal processing, and there is little influence on vibration and sound frequency noise [16].Fourthly, the acoustic emission sensor responses quickly with high sensitivity in its working conditions. Therefore, this method has the good application prospects and is used widely compared with the former two methods nowadays. 2.4 The Current Monitoring Method of the Tool Status Currently, it is a new popular method to utilize the monitoring motor current signals to monitor the tool wear in foreign factories. During the cutting process, if the tool wear and breakage occur, the cutting force correspondingly changes, which would cause changes in motor's output torque, and the motor's power increases along with it, which leads to the corresponding changes in motor current [17]. The current monitoring method achieves an indirect on-line real-time to determine tool wear and breakage by monitoring the motor current change. Based on LABVIEW technology, Nanchang University, Feng Yan [l8] and others achieved a collection of the machine spindle motor current signals, storage and analysis. The online monitoring electric current's change situation reflected the status of tool wear, and proposed the mathematical model between the spindle current and cutting parameters. Besides, they applied experiments to verify the effectiveness and practicality of the system. Through the above investigated and Compared with the method of cutting force, we can get the results that the machine power method has the advantages as follows: On the one hand, the convenience of measuring signals, and can avoid disturbing from cutting chip environment, oil, smoke, vibration and so on, the monitoring device is easy to be installed. On the other hand, through monitoring the motor current to distinguish the changes in tool condition, which has the features of the convenience to extract current signals, and is convenient to install sensors, what is more, it could not be affected by processing environment. Therefore, it is convenient to be applied in production, and now many famous domestic factories are beginning utilize the method to monitoring tools cutting status. 2.5 Based on Multi-sensors Monitoring Method Although each sensor has its own characteristics, it can describe the measurement object only in a certain range from one hand. Due to the influence of external interference noise, and it will have a greater measurement errors sometimes. So there is no any other sensor can guarantee to provide comprehensive, accurate information at any time, this is the deadly fault to single sensor. In fact, single sensor can only provide partial and inaccurate information. In such condition, based on the multiple-sensors
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monitoring method was proposed by many scholars. YanShan University, ZhiYanLiu [19], who used the method of acoustic emission (AE) in combination with the motor current parameters of multi-feature detection, developed the tool breakage monitoring system with its own features. And established a mathematical model, achieved parameters measurement, and experimentally proved that the system on-line monitoring tool breakage is feasible. After many social investigation and statistics, we discovered a phenomenon that it is very popular to apply the multi-sensors monitoring method in many common domestic and foreign factories, and the main reason is that the multi-sensors data integration has some advantages that we discovered through a further research. And the advantages are as following: Firstly, it could acquire the tested object or environmental information more accurately. What’s more, it also could obtain information with higher accuracy and reliability than any other single sensor. Secondly, it could obtain the independent feature information that one single sensor could not through the sensors complement with each other. Thirdly, it could acquire the same information with less time and lower price to compare with the traditional single sensor. Finally, according to the priori knowledge of the system, it could complete tasks of classification, judgment, decisionmaking and so on through processing the integration information of multi-sensors. According to the above research, we can draw a conclusion that this method is considered as the main direction of the development of tool wear monitoring in the near future, which would be a great significance for improving the utilization of machine and reducing the economic losses due to the tool wear.
3 Conclusions The tool wear online monitoring is an important research direction in advanced manufacturing technology, which is of a great significance for improving production efficiency, reducing processing cost and guaranteeing the processing quality. According to investigate, analyze and comparison in this paper, we can conclude that the based on multi-sensors monitoring method system to monitor tool status can effectively improve the discriminate accuracy, and with higher reliability, and is more suitable for actual production. Therefore, this method would be the main direction of the development of tool wear monitoring in the near future.
References 1. Ji, Y.: Life Prediction of Tool Wear in FMS environment research. Shijiazhuang Vocational and Technical College 17(6), 35–37 (2005) 2. Adam, G., Jin, J., Oban, P.E.: State—of-the-art methodsand results in tool condition monitoring: a review. Int. J. Adv. Manuf. Technol. (26), 693–710 (2005) 3. Feng, Q.g.: Study of the Cutting tool condition online monitoring strategies. Shanghai Jiaotong University master’s degree paper (2004) 4. Li, Y.h.: Study of the tool condition with multi-sensors monitoring strategies. Shanghai jiaotong university, PHD paper (1999) 5. Li, Y.h.: Study of the tool condition with multi-sensors monitoring strategies. Shanghai jiaotong university, PHD paper (1999)
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6. Jemielniak, K.: Tool Wear Monitoring Based on a Non-Monotonic Signal Feature. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 220(2) (2006) 7. Silva, R.G., Wilcox, S.J., Reuben, R.L.: Development of a system for monitoring tool wear using artificial intelligence techniques. Proceedings of the Institution of Mechanical Engineers, 220(8) (2006) 8. Spirgeon, D., Slater, R.A.C.: In process indication of surface roughnessusing a fibre potics transducer. In: Proc. III. 15th Int. Machine Tool Design and Research Cone, pp. 339–347 (1974) 9. Kang, S.L., Yi, S.-M., Lu, Y.: LABVIEW-based cutting force monitoring system. Combination Machine Tool & Automation Engineering Technology (8) (2004) 10. Shao, H.: Study and development the system of Milling power monitoring tool monitoring system. Shanghai Jiaotong University, PHD paper (1994) 11. Sadat, A.B., Kidd, S.R., Hand, D.P.: Acoustic emission monitoring of tool wear during the face milling of steels and aluminium alloys using a fibre optic sensor Part 2: frequency analysis. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 211(4) (1997) 12. Lee, L.C., Karpovich, R.J.: A study of the relationship between remote thermocouple temperatures and tool wear in machining. Int. J. Prod. Res. 25, 129–141 (1977) 13. Chen, x.-q., Li, x.n., Deng, m.: Metal cutting process in the acoustic emission phenomenon and its research significance. Journal of Chang Sha University of Electric Power 16(1), 75–76 (2001) 14. Moriwaki, T., Tobito, M.: A new approach to automatic detection of life of coated tool based on acoustic emission measurement. Trans. ASME. J. Eng. Ind. 112, 212–218 (1990) 15. Blum, T.: Mill breakage of acoustic emission detection technology. Combination machine tool and automation processing technology (3) (1992) 16. Feng, Y., Luo, l., Xia l.: LABVIEW-based online monitoring system for tool wear. Sentinel surveillance (12) (2006) 17. Jun, z., Wang, x.: Monitoring.: Motor current to determine the tool wear and breakage. New Technologies (6) (1990) 18. Feng, Y., Luo l., Xia l.: LABVIEW-based online monitoring system for tool wear. Sentinel Surveillance (12) (2006) 19. Liu, Z.y., Wang, j.: Using acoustic emission and electric current gun detection technology to achieve the monitoring of tool wear, mechanical, May 2 (1999)
Magnetic-Field-Based 3D ETREE Modelling for Multi-Frequency Eddy Current Inspection Yu Zhang1 and Yong Li2 1
Engineering College, Air Force Engineering University, ShaanXi, Xi’an, 710038, P.R. China [email protected] 2 School of Aerospace, Xi’an Jiaotong University, ShaanXi, Xi’an, 710049, P.R. China [email protected]
Abstract. More and more solid-state magnetic field sensors such as Hall devices are used in eddy current inspection (EC) to acquire magnetic field signals. This work extends the previous analytical model, i.e. 2D Extended Truncated Region Eigenfunction Expansion (ETREE) of EC, and focuses on establishment of 3D ETREE of multi-frequency eddy current inspection (MFEC) on stratified conductors, while taking into account the solid-state magnetic field sensors for field quantification and rectangular coils for field excitation. 3D Finite Element Modelling (FEM) and a hybrid modelling are adopted for verification of the established model. It has been noticed that the 3D ETREE implements the fast and accurate computation of magnetic field signals of MFEC. Following that, the directional characteristics of EC with rectangular excitation coils are investigated, which reveals that the coil width contributes more to the measurement sensitivity than the coil length, and benefits the evaluation of defects and anisotropic conductivity profile of conductors in the follow-up study. Keywords: Eddy current inspection, Magnetic field, Extended Truncated Region Eigenfunction Expansion, Finite element modelling.
1 Introduction To evaluate the integrity and structural health of metallic structures such as stratified conductors, Electromagnetic Non-destructive Evaluation (ENDE) techniques, especially Eddy Current (EC) and transient eddy current, are preferred and used in realtime inspections [1]. Eddy-current testing traditionally relies on the detection of impedance changes in a pickup coil as it moves across the inspected specimen. Accordingly, the theoretical modelling for EC previously was implemented merely to predict: (1) the impedance signals from the stranded induction coils for time-harmonic field [2], [3]; and (2) the electromotive force (EMF) signals from coils for transient field [4]. However, it is formidable for traditional EC to detect deep flaws in conductive materials, because low frequency excitation is demanded to allow eddy currents to penetrate deeply into the conductors while the sensitivity of normal pickup coils, which is proportional to D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 221–230, 2011. © IFIP International Federation for Information Processing 2011
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the excitation frequency, is decreased. In light of this, it is more advantageous to measure the magnetic field using solid-state magnetic field sensors such as Hall sensors, giant magnetoresistive (GMR) sensors, or superconducting quantum interference devices (SQUIDs) [5], [6] are used. The theoretical modelling for EC in conjunction with solid-state magnetic field sensors has been conducted for years. Ward and Moulder proposed an expression for transient EC signals to layered conductive structures using Hall device based on the infinite integral formulation developed by Dodd and Deeds [7]. However, the sensing element in Hall devices was not taken into account. Li and Tian extended the Truncated Region Eigenfunction Expansion (TREE) modelling and made it capable of predicting the magnetic field signals while the dimension of the sensing element was considered [8], [9], [10]. Nevertheless, the model was only applicable to circular coils rather than rectangular coils. This paper elaborates the formulation of expressions of 3D magnetic field for Directional Eddy Current Inspection (DEC) with rectangular coils via 3D Extended Truncated Region Eigenfunction Expansion modelling (3D ETREE), which concerns the geometry of rectangular coils as well as the dimension of sensing elements. The rest of the paper is organised as follows: Section 2 presents the formulation of the closed-form expressions of magnetic field signals from solid-state magnetic field sensors; the verification of 3D ETREE by comparing with simulation results from 3D Finite Element Modelling (FEM) and a hybrid modelling is exhibited in Section 3; Section 4 elaborates the analysis of directional characteristics of DEC via investigation of the influence of the length and width of a rectangular coil on the measurement sensitivity of DEC to conductivity variation in a conductive halfspace.
2 Theoretical Background The 3D ETREE modelling using Second-order Vector Potential (SOVP) formulation is conducted with a rectangular coil (x1≠y1, x2≠y2) placed over the layered conductive sample which is shown in Figure 1. The rectangular coil, with N number of windings, is supposed to be supplied with a pulsed excitation current, each harmonic of which is written as I(ωi) at the angular frequency of ωi. z hx x2 x1
0.5hx
z2 y
z=0
x0 z1
L
c1 c2 σ1 μ1
z=-d1
x
σ2 μ2
z=-d2
σ3 μ3
z=-d3
...
z=-dL-2
σL-1 μL-1
z=-dL-1
σL μL
(a) Fig. 1. A rectangular coil and a magnetic field sensor placed over a multilayered conductor: (a) side view in y-direction; (b) side view in x-direction
Magnetic-Field-Based 3D ETREE Modelling for MFEC z
hy y2
0.5hy
y1
z2 x
223
y0 z1
z=0
W
c1 c2
y
σ 1 μ1
z=-d1
σ 2 μ2
z=-d2
σ 3 μ3
z=-d3
...
z=-dL-2
σL-1 μL-1
z=-dL-1
σL μL
(b) Fig. 1. (continued)
2.1 Magnetic Field at a Point of (x, y, z) Using SOVP formulation, the magnetic vector potential can be written as [1]:
A = ∇ × (Wa z 0 + z0 × ∇Wb ) .
(1)
Thus, magnetic field between the bottom of the rectangular coil and the upper surface of the conductor (0≤z≤z1) can be expressed as [2]: ⎛ ∂Wa ⎞ B = ∇⎜ ⎟ . ⎝ ∂z ⎠
(2)
Similar to 2D ETREE modelling, the infinite problem region in 3D is truncated and recast with finite lengths of hx and hy in x and y directions, respectively, which can be seen in Figure 1. The truncation results in the replacement of the infinite integrals with series Eigenfunction expansions. The Eigenvalues (kxn and kym) in two truncation directions are computed by applying the boundary condition B = 0 at z=0, x=hx and y=hy, which gives [2]: k xn =
nπ mπ , k ym = , hx ≠ h y . hx hy
(3)
The magnetic field for each harmonic in the pulsed excitation current is written as:
(
)
⎡sin (k xn x )sin k ym y ⎢ ∞ ∞ ⎞ V ⎢ ⎛ λmn z B (ωi ) = + e− λmn z mn,1 ⎟ ⎢× ⎜⎜ e U mn,1 ⎟⎠ m =1 n =1 ⎢ ⎝ ⎢× C k x + k y + z ym 0 0 ⎣ mn xn 0
∑∑
(
⎤ ⎥ ⎥ ⎥ . ⎥ ⎥ ⎦
)
(4)
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where, x0 , y0 and z0 are unit vectors. Cmn denotes the coil coefficient for rectangular coils, which is written as:
(
)
⎧ 8 μ 0 χ mn e − λmn z1 − e − λmn z 2 NI (ωi ) ⎛ k xn hx ⎞ ⎛ k ym h y ⎞ ⎟ sin ⎜ ⎟ sin ⎜ ⎪C mn = (z 2 − z1 )chx hy k xn k ym λmn ⎝ 2 ⎠ ⎜⎝ 2 ⎟⎠ ⎪ ⎪ ⎪ χ = sin k xn − k ym c + k xn x1 − k ym y1 − sin k xn x1 − k ym y1 ⎪ . 2( k xn − k ym ) ⎨ ⎪ sin k xn + k ym c + k xn x1 + k ym y1 − sin k xn x1 + k ym y1 ⎪ − ⎪ 2( k xn + k ym ) ⎪ ⎩⎪c = x2 − x1 = y 2 − y1
[(
]
)
[(
(
)
]
)
(
)
(5)
Vmn,1/Umn,1 is the conductor reflection coefficient in the region between the bottom of the coil and the upper surface of the conductor, which is computed by using the iterative equation:
⎧ ⎛ γ mn, j −1 γ mn, j ⎞ − 2γ mn , j ( d j − d j −1 ) ⎛ γ mn, j −1 γ mn, j ⎞ ⎟e ⎟U j +1 ⎪U mn, j = ⎜ − + V j +1 + ⎜ ⎜ ⎟ ⎜ ⎟ μ μ μ μ ⎪ j ⎠ j ⎠ ⎝ j −1 ⎝ j −1 ⎪ ⎛ γ mn, j −1 γ mn, j ⎞ − 2γ mn , j ( d j − d j −1 ) ⎛ γ mn, j −1 γ mn, j ⎞ ⎪ ⎟e ⎟U j +1 + − V j +1 +⎜ ⎪Vmn, j = ⎜⎜ ⎟ ⎜ μ j −1 ⎟ μ μ μ j j j − 1 ⎪ ⎝ ⎠ ⎝ ⎠ ⎪⎪ 2 2 2 . ⎨ γ mn, j = λmn + jωi μ jσ j ; λ mn = k xn + k ym ⎪ γ mn, L −1 γ mn , L γ mn, L −1 γ mn, L ⎪U = + − ; Vmn, L = ⎪ mn, L μ L −1 μL μ L −1 μL ⎪ ⎪ γ mn, j = λmn j =0 ⎪ ⎪d ⎪⎩ j j = 0 = 0
(6)
The subscript j iterates from L-1 to 1. 2.2 Integral of Magnetic Field over a Sensor Volume
Suppose the volume of the sensor element is 2L×2W×(c2-c1). The location of the sensor is at the point of (x0, y0, c0), c0=(c2+c1)/2. Magnetic field within the sensor element, which is placed between the bottom of the rectangular coil and the upper surface of the first layer of the conductor can be expressed in 3D as: Bv (ωi ) =
∫ B (ω )dv v
i
4 LW (c2 − c1 )
=
∫ ∫ ∫ B (ω )dxdydz x y z
i
4 LW (c2 − c1 )
.
(7)
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225
Two types of sensor dimensions are considered in the model: cubiod shape and cylindrical shape. For a cubiod-shaped sensor with dimension of 2L×2W×(c2-c1), Eq. (7) is rewritten as: ∞
Bv (ωi ) =
∞
(
∑∑
Cmn FmnGmn k xn x0 + k ym y0 + z0 k xnk ym m =1 n =1
)
LW (c2 − c1 )
.
(8)
where,
(
) (
)
⎧Fmn = sin (k xn L )sin (k xn x0 )sin k ymW sin k ym y0 ⎪⎪ . ⎡ Vmn,1 − λ (c − c ) ⎤ eλmn c2 − eλmn c1 ⎨ e mn 2 1 ⎥ ⋅ ⎪Gmn = ⎢1 + U λmn ⎪⎩ ⎥⎦ ⎢⎣ mn,1
(9)
For cylindrical-shaped sensor with dimension πR2×(c2-c1), R=L=W, Eq. (7) is modified as: ∞
Bv (ωi ) =
∞
(
∑∑
Cmn EmnGmn k xn x0 + k ym y0 + z0 k xn k ym m =1 n =1 R (c2 − c1 )
) .
(10)
where, ⎧[cos(k xn x0 )H 1 (k xn R ) + sin (k xn x0 )J 1 (k xn R )] ⎫ E mn = ⎨ ⎬ . ⎩× cos k ym y 0 H 1 k ym R + sin k ym y 0 J 1 k ym R ⎭
[ (
) (
)
(
) (
)]
(11)
It is noted that Emn, Fmn and Gmn are the sensor coefficients, which depend on the sensor dimensions. Eqs. (8)-(11) give the expressions of averaged magnetic field within a sensor volume, which can be used for predicting the magnetic field signals acquired from solidstate magnetic field sensors. Following the formulation of field in frequency domain, the discrete time-domain signal i.e. the transient EC response to stratified conductors can be recovered and expressed in the Fourier manner as [9]: Bv (ti ) =
1 M
M −1
∑
2πj
Bv (ωi )e M
ki
k = 0,1,2,..., M − 1 .
(12)
k =0
2πj
where, e M is a primitive M’th root of unity. It is noteworthy that Eq. (12) can be efficiently calculated by using MATLAB routine ‘ifft’ based on Inverse Fast Fourier Transform.
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3 Corroboration In an effort to verify the 3D ETREE modelling, Finite Element Modelling (FEM) is used to simulate the field signals from a cubiod-shaped sensor, when a rectangular coil is placed over a conductive plate. The sensor is placed at the centre of the rectangular coil and 1mm above the upper surface of the plate. The dimension of the sensor element is: L=W=0.9mm; c2-c1=0.5mm. The parameters of the coil are listed in Table 1. The conductivity and relative permeability of the conductive plate are 37MSm-1 and 1, respectively. Table 1. Parameters of the excitation coil Coil width 2y2 / mm 16 Number of turns N 500
Coil length 2x2 / mm 19 Design Lift-off c1 / mm 2
Coil height z2-z1 / mm 7 Excitation frequency 10Hz-10kHz
Winding thickness y2-y1 / mm 5 Current in the coil I / mA 500
The verification is conducted via simulations in frequency domain. The number of elements (NOE) used in FEM is 48608 and the number of degrees of freedom (NOD) is 207437. The z-component of magnetic field is acquired and compared. The real and imaginary parts of the field signals against frequency are compared between ETREE and FEM. The results are shown in Figure 2(a). The ETREE results with and without consideration of the dimension of sensor element are shown in Figure 2(b). The evaluation of agreement in the two comparison cases is realised by using Normalised Root Mean Square Deviation (NRMSD). The computed NRMSD values are listed in Table 2.
(a)
(b)
Fig. 2. Comparison of the magnetic field signal (z-component) predicted by ETREE and FEM: (a) Case 1: ETREE considering sensor dimension vs. FEM; (b) Case 2: ETREE considering sensor dimension vs. ETREE predicting field at sensor point
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Table 2. Computed NRMSD values for the two comparison cases Case 1: ETREE considering sensor dimension vs. FEM NRMSD
Real part 0.20%
Imaginary part 0.17%
Case 2: ETREE considering sensor dimension vs. ETREE predicting field at sensor point Real part Imaginary part 2.48% 0.57%
It can be seen in Figure 2(a) and Table 2 that the predicted signals from sensors by using 3D ETREE have good agreement with that acquired from FEM simulations, since the NRMSD values are much less than 1%, which indicates less residual variance between results from 3D ETREE and FEM. It is also note worthy that the computation time of 3D ETREE (less than 2s) is much less than that of FEM (4 hours) due to large number of NOE and high NOD. Therefore, 3D ETREE can be found advantageous over FEM in terms of high computation accuracy and less simulation time, which facilitates the forward modelling and inverse modelling of EC with rectangular coils. Figure 2(b) and Table 2 also presents the comparison results regarding 3D ETREE with and without consider the sensor dimension in the modelling. The discrepancy is up to 2.5%, which indicates that the sensor dimension should be taken into account if higher modelling accuracy is pursued, especially in the case where the dimension of sensor is comparable to that of the excitation coil.
4 Sensitivity Study for DEC Following the verification of 3D ETREE, the sensitivity is investigated for DEC with pulsed excitation. The maximum amplitude of the pulsed current is 500mA. The cycle and the rising time constant of the current are 5ms and 100μs, respectively. The peak value (PV) against different conductivities of an isotropic conductive half-space is simulated with reference to various dimension of the rectangular coil. Thanks to the high-efficiency 3D ETREE, the database depicting the relation of PV with different dimensions of rectangular coils can be readily established. In order to obtain PV, the conductivity of the half-space varies and is written as: σi= σ0(1+Δσi), where, σ0=37MSm-1; Δσi varies from -1% to 1%. The PVs are extracted in transient EC differential signals ΔBzi, after subtracting the individual signals Bzi (when Δσi≠0) into the reference signal Bz(σ0) (when Δσi=0). For a particular rectangular coil with the length y=19.5mm and the width x=6mm, the PV against Δσi is presented in Figure 3(a). Figure 3(b) shows the plot with errorbars indicating the variation in the curve when (1) the coil length is increased to 21.45mm; (2) the coil width is increase to 6.6mm. It can be seen in Figure 3(a) that the curve of PV exhibits good linearity when Δσi varies in the small region from -1% to 1%. The slope of the curve (kab=dPV/dΔσi), which is -0.1 in Figure 3(a) indicates the measurement sensitivity to the variation in the sample conductivity. High value of curve slope implies that high measurement sensitivity, which gives significant variation in PV due to the change in conductivity. The curve slope is found varying with the coil dimension, which can be seen in Figure 3(b).
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(a)
(b)
Fig. 3. PV against Δσi for (a) the coil (x=19.5mm and y=6mm) and (b) coils (x=19.5mm and y=6mm; x=21.45mm and y=6mm; x=19.5mm and y=6.6mm)
The measurement sensitivities against different combinations of x and y of the coil (6mm≤x≤y≤19.5mm) are modelled. In order to investigate the influences of x and y on the measurement sensitivity, surface fitting using a quadratic function is implemented after the database (kab vs. coil dimension) is built up. The results are presented in Figure 4.
Fig. 4. The measurement sensitivity vs. coil dimension
The quadratic fitting function is written as:
(
) (
)
k ab = y 8.455 × 10 −2 − 4.659 y + x 1.682 × 10 −1 − 8.662 x + 3.248 × 10 −4 .
(13)
The fitted curve has 98% agreement with the database, which is acceptable for the investigation. The influence of x and y on the sensitivity kab can subsequently be analysed via taking first-order derivative of kab with respect to x as well as y, which can be written as: κ x = ∂ (k ab ) ∂x and κ y = ∂ (k ab ) ∂y . Since the magnitudes of κx and κy are of interest, the absolute values of κx and κy are computed and shown in Figure 5.
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Fig. 5. Influence of x and y on the sensitivity kab: plots of κ x = ∂ (k ab ) ∂x and κ y = ∂ (k ab ) ∂y
It can be found in Figure 2 that the width (x) plays more important role than the length (y) regarding the contribution to the measurement sensitivity to conductivity variation. The reason lies in the fact that the distance between eddy currents flowing oppositely under the two lengths of the coil varies with the coil width. Small width results in more cancellation of eddy currents. Since eddy currents induce the secondary magnetic field, which is depends on the conductivity of the sample, the cancellation of eddy currents causes decrease of measurement sensitivity. As can be seen in Figure 5, when the width increases, the rate of enhancement of measurement sensitivity rises, which is because less eddy currents are cancelled out. Although the increase in coil length enhances the measurement sensitivity due to increased distance between eddy currents flowing oppositely under the two coil widths, the enhancement due to the coil length is less than that due to the coil width. This is because of the fact that the length is larger than the width, and thus the eddy current density under the coil width is higher than that under the coil length. Therefore, the dependency of measurement sensitivity on the coil length is less than that on the coil width. Compared with circular coils whose sensitivity is dependent on the coil diameter, the rectangular coils show the distinct characteristics of measurement sensitivity, which is mostly influenced by the coil width. The contribution to the sensitivity from the coil width is more than that from the coil length. As a result, EC with a rectangular coil shows the directional measurement sensitivity, which is along the width of the coil. In such case, DEC is realised, which is advantageous over traditional EC in terms of (1) high detectability of cracks with different orientations; (2) better characterisation of anisotropic distribution of conductivity due to applied stress or strain in particular directions.
5
Conclusion
This paper presents the 3D ETREE modelling for prediction of magnetic field signals from solid-state magnetic field sensors, which can be placed at an arbitrary location between bottom of the excitation and the upper surface of the conductor. The consideration of sensor dimension in the formulation results in the new coefficient in the
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expression. The so-called sensor coefficient is dependent on the sensor geometry, and indispensable when (1) EC with utilisation of magnetic field sensor arrays is simulated; (2) the sensor dimension is comparable to coil size. 3D ETREE facilitates the investigation of directional characteristics of measurement sensitivity i.e. change in PV due to conductivity variation in samples for DEC. The influences of the coil width and length on the DEC sensitivity is analysed by setting up a database depicting the relation between measurement sensitivity and coil dimension. It can be noticed that the contributions from the length (x) and the width (y) to the measurement sensitivity are not identical. The coil width is dominant in enhancement of measurement sensitivity. Therefore, compared with traditional EC with circular coils, which has the measurement sensitivity equally on the circumference of the probes, DEC is found having the dominant measurement sensitivity along the coil width, which benefits the evaluation and characterisation of natural cracks and anisotropic conductivity due to stress/strain. The experimental work on verification of 3D ETREE and the directional characteristics of DEC, which has been found in theoretical study, is currently underway. Further work would be focused on the identification, characterisation and reconstruction of natural defects and inhomogeneous conductivity profiles of conductors. Acknowledgement. The authors would like to thank Miss. Xinhua Li and Prof. Gui Yun Tian of Newcastle University, UK for 3D FEM simulation and valuable discussions.
References 1. Sundararaghavan, V., Balasubramaniam, K., Babu, N.R., Rajesh, N.: A multi-frequency eddy current inversion method for characterizing conductivity gradients on water jet peened components. NDT&E Int. 38, 541–547 (2005) 2. Theodoulidis, T.P., Kriezis, E.E.: Eddy Current Canonical Problems (with Applications to Nondestructive Evaluation). TechScience Press (2006) 3. Theodoulidis, T.P., Bowler, J.R.: Eddy current interaction with a right-angled conductive wedge. Proc. of the Royal Society of London A 461, 3123–3139 (2005) 4. Yang, H.C., Tai, C.C.: Pulsed eddy-current measurement of a conducting coating on a magnetic metal plate. Mea. Sci. & Tech. 13, 1259–1265 (2002) 5. Tian, G.Y., Sophian, A.: Study of magnetic sensors for pulsed eddy current techniques. Insight. 47, 277–280 (2005) 6. Tian, G.Y., Sophian, A., Taylor, D., Rudlin, J.: Multiple sensors on pulsed eddy-current detection for 3D subsurface crack assessment. IEEE Sensors Journal 5, 90–96 (2005) 7. Ward, W.W., Moulder, J.C.: Low frequency, pulsed eddy currents for deep penetration. Rev. of Prog. in QNDE 17, 291–298 (1998) 8. Li, Y., Theodoulidis, T.P., Tian, G.Y.: Magnetic field-based eddy current modelling for multilayered specimen characterization. IEEE Trans. on Mag. 43, 4010–4015 (2007) 9. Li, Y., Tian, G.Y., Simm, A.: Fast analytical modelling for pulsed eddy current evaluation. NDT & E Int. 41(6), 477–483 (2008) 10. Tian, G.Y., Li, Y., Mandache, C.: Study of lift-off invariance for pulsed eddy-current signals. IEEE Trans. on Mag. 45, 184–191 (2009)
Measurement of Self-emitting Magnetic Signals from a Precut Notch of Q235 Steel during Tensile Test Lihong Dong, Binshi Xu, and Shiyun Dong National Key Laboratory for Remanufacturing, Academy of Armored Forces Engineering, Beijing, 100072, P.R. China [email protected]
Abstract. In order to investigate the approach to characterize the damage behavior of ferromagnetic material components with flaw by metal magnetic memory testing, a sheet specimen with a precut notch of Q235 steel was chosen to measure the self-emitting magnetic signals on its surface during tensile test. The results showed that an abnormal magnetic signal appeared at the position of the precut notch after early loading and then transformed gradually to a clear magnetic abnormal peak with the tensile load increasing, which implied that the variations of self-emitting signals can reflect the influence of applied load on the specimen dynamically. The above-mentioned phenomenon was discussed from the point of view of magnetomechanical effect. Keywords: self-emitting signals, applied load, damage, magnetic abnormal peak, effective magnetic field.
1 Introduction Ferromagnetic parts are widely used in engineering fields [1-3]. During their manufacturing process or operation, various defects will unavoidably occur in the materials [4-6]. In most cases the ferromagnetic components have to work with these defects. Hence, monitoring the changes of the defects dynamically in service is very important to ensure the safety of the components. However, most of the available non-destructive testing methods, such as ultrasonic inspection, eddy current inspection, penetrant inspection, and magnetic particle inspection, can only examine macroscopic defect statically, which are not suitable for monitoring microscopic defect change dynamically[7]. At present acoustic emission testing is the only dynamic method for early damage diagnosis. However, the measured components must be loaded by using acoustic emission testing, and it is difficult to analyze the acoustic emission signals due to existing noise interference, which limits the method practical application[8,9]. Metal Magnetic Memory testing (MMMT) is a relatively new non-destructive testing method which was first put forward by Russian researchers[10-12]. The method is regarded as another non-destructive technique for early damage diagnosis, which can find the stress concentration zone of ferromagnetic materials. However, due to lack of fundamental investigation, it is still a problem how to characterize the damage behavior of ferromagnetic materials by using metal magnetic memory signals[13]. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 231–236, 2011. © IFIP International Federation for Information Processing 2011
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In this paper a sheet specimen of Q235 steel with a precut surface notch was chosen to find the mode of metal magnetic memory method characterizing damage behaviour by means of tensile test.
2 Experiment 2.1 Specimen Preparation The test material is Q235 steel which is widely used in different engineering fields. Its chemical composition and mechanical properties can be found in references [14]. The geometry and dimension of specimen are shown in Fig.1. A precut notch, which length is 10mm, width is 0.5mm, depth is 0.5mm, was machined on the center of the specimen surface by electric discharge machining technique. Three measured lines of 90mm length with an equal interval were arranged through the notch on the surface of the specimen.
Fig. 1. The precut notch and measured lines on the specimen
2.2 Experimental Set-Up The tensile test was carried out with a servo hydraulic MTS810 testing machine with static error ±0.5%. The metal magnetic memory signals, Hp(y) signals (i.e. the component of self-leakage field), were measured by an EMS-2003 Metal Magnetic Memory instrument. In the tensile test, the specimen was vertically held between the upper and lower grip holders of the testing machine. When loaded to a predetermined load and retained some time, the specimen was taken carefully from the machine and placed on a non-magnetic electrical scanning platform along the south–north axis. Then, the Hp(y) values of all three measured lines were collected. After measurement, the specimen was loaded again to a higher predetermined stress, and the above measuring procedure was repeated until the specimen failed.
3 Results and Discussion 3.1 Distributions of Hp(y) Signals during the Test During the test, only elastic deformation occurred in the specimen if the applied load was less than 40kN. The specimen yielded when the tensile load was up to 49kN, and at last it was failed at 68kN. The distributions of Hp(y) signals at initial state before loading, 1kN, 10kN, 40kN, 60kN and 65kN respectively were shown in Fig.2.
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Fig. 2. The distribution of Hp(y) signals on the three measured lines during tensile test
In Fig.2 the red circle indicated the position of the precut notch. Because the specimen was demagnetized before tensile test, the value of initial magnetic signals were very small, which were in the range of 20A/m. The initial Hp(y) curve of the specimen had a curly feature to some degree, no abnormal magnetic signals were observed on the position of the precut notch. After a tensile load of 1kN was applied to the specimen, the magnetic signal curves on the three measured lines presented a feature of magnetic ordering, which left signals were negative and right signals were positive. At that time a very weak abnormal signal was observed at the position of the precut notch, which was induced by the load of 1kN. If the position of the precut notch was not known beforehand, the abnormal signal might be ignored. The result showed that the applied load can excite the precut notch to generate self-emitting signals and change the magnetism of the specimen. However, the load of 1kN was too small to produce a strong feature of abnormal magnetic signals. When loaded up to 10kN, a rough abnormal magnetic peak appeared, indicating the existence of the precut notch. At 40kN, the shape of the abnormal magnetic peak became clearer continuously. When the applied load increased up to 60kN, the magnetic signal curve became an approximate sloping straight line, and the abnormal magnetic peak at the position of the precut notch showed a clear feature of crest and trough. The last figure indicated the magnetic state on the measured lines before failure. At that time the applied load is 65kN, and the specimen had a high elongation.
±
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Moreover, observed by a reading microscope, it was found that the width of the precut notch increased whereas the depth of the notch decreased, leading to the abnormal magnetic signals weakening. The above results showed that a applied load can change the magnetism of ferromagnetic materials. With the applied load increasing, the magnetism increased. Hence the precut notch emitted magnetic signals which presented a feature of abnormal magnetic peak. Moreover, the distributions of the abnormal magnetic peak changed with the applied load increasing. Hence it can be inferred that metal magnetic memory testing has the ability to monitor the variations of defect in ferromagnetic materials dynamically. During measurement ferromagnetic materials need not loaded. The feature signals of defect are clear enough to further analyze. 3.2 Load-Induced Magnetism Enhancement The above mentioned results showed that an applied load on the specimen, even if very small, could change the magnetism of the tested ferromagnetic material under the Earth magnetic field. Thus the applied load can be seen as a external excitation, which cause the abnormal magnetic signals occurring and enhancing at the precut notch. According to the magnetomechanical effect, when an axial tensile load is applied to ferromagnetic specimen, the specimen will deform, leading to the appearance of stress energy of Eσ[15]: 3 Eσ = − σλ (cos 2 θ − ν sin 2 θ ) 2
(1)
Consequently, the applied load alter the magnetism of the ferromagnetic specimen, causing an effect magnetic field Hσ on the specimen: Hσ =
1 ∂Eσ
μ 0 ∂M
=
3 σ ∂λ ( ) σ (cos 2 θ − ν sin 2 θ ) 2 μ 0 ∂M
(2)
Under the effect of Hσ, on the one hand, the magnetic charges will accumulate on both ends of the specimen, causing different polarities, N and S, appearing at the two ends. Hence the magnetic signal curve exhibited good linearity after loading, which the left signals were negative while the right signals were positive. With the axial load increasing the effect magnetic field Hσ increased, thus the magnetism of the specimen increased too, leading to the gradual disappear of the curl of the magnetic signal curve and the increase of the linearity and the slope coefficient of magnetic signal curve. On the other hand, when the specimen was magnetized by the effect magnetic field, the precut notch on the surface cut the path of magnetic lines of Hσ. Similarly, the magnetic charges with different polarities accumulated on both sides of the notch. Consequently, the abnormal magnetic peak gradually appeared with the load increasing. Consequently, the amplitude of load applied to ferromagnetic materials and their deformation can be inferred by measuring and analyzing the feature signals of defects, thus the damage degree of ferromagnetic components can be known in service. The schematic diagram was shown in Fig.3.
Measurement of Self-emitting Magnetic Signals from a Precut Notch of Q235 Steel
S
-
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Fig. 3. The generation of magnetic polarities induced by Hσ on the surface of the specimen
4 Conclusions When a axial tensile load was applied to the ferromagnetic specimen, an effective magnetic field was occurred, causing opposite magnetic charges accumulation on the both ends of the precut notch. Hence, the precut notch emitted abnormal magnetic signals spontaneously due to the excitation of the effective magnetic field. The abnormal magnetic peak gradually appeared with the applied load increasing, which indicated the position and amplitude of the precut defect. It is feasible to dynamically monitor the damage degree of ferromagnetic materials with defects by means of metal magnetic memory testing.
References 1. Pešička, J., Kužel, R., Dronhofer, A., Eggeler, G.: The evolution of dislocation density during heat treatment and creep of tempered martensite ferrite steels. Acta Materialia 51, 4847–4862 (2003) 2. Hu, J.-f., Yang, J.-g., Fang, H.-y., Li, G.-m., et al.: Temperature, stress and microstructure in 10Ni5CrMoV steel plate during air-arc cutting process. Computational Materials Science 38(4), 631–641 (2007) 3. Colombi, P., Poggi, C.: Strengthening of tensile steel members and bolted joints using adhesively bonded CFRP plates. Construction and Building Materials 20(1-2), 22–33 (2007) 4. Gao, N., Dwyer-Joyce, R.S., Beynon, J.H.: Effects of surface defects on rolling contact fatigue of 60/40 brass. Wear, 225–229, 983–994 (1999) 5. El-Batahgy, A., Zaghloul, B.: Fatigue failure of an offshore condensate recycle line in a natural gas production field. Materials Characterization 54(3), 246–253 (2005) 6. Kuźnicka, B., Stróżyk, P.: Failure analysis of disintegrator beaters. Engineering Failure Analysis 13(1), 155–162 (2006) 7. Li, J.-w., Chen, J.-m.: Non-destructive testing handbook. Mechanical Engineering Publisher, Beijing (2002) (in Chinese) 8. Ken, W., Junichiro, N., Mitsuyasu, I., Hiroshi, Y.: Localized failure of concrete in compression identified by AE method. Construction and Building Materials 18(3), 189–196 (2004) 9. Al-Ghamd, A.M., Mba, D.: A comparative experimental study on the use of acoustic emission and vibration analysis for bearing defect identification and estimation of defect size. Mechanical Systems and Signal Processing 20(7), 1537–1571 (2006) 10. Doubov, A.A.: A study of metal properties using the method of magnetic memory. Metal Science and Heat Treatment 39(9-10), 401–402 (1997) 11. Doubov, A.A.: Screening of weld quality using the magnetic metal memory effect. Welding in the world 41, 196–198 (1998)
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12. Doubov, A.A.: A Technique for Monitoring the Bends of Boiler and Steam-Line Tubes Using the Magnetic Memory of Metal. Thermal Engineering 48(4), 289–295 (2001) 13. Dong, L., Xu, B., Dong, S., et al.: Investigation of metal magnetic memory signals from the surface of low-carbon steel and low-carbon alloyed steel. J. Cent. South Univ. Technol. 14(1), 24–27 (2007) 14. Dong, L., Xu, B., Dong, S., et al.: Variation of stress-induced magnetic signals during tensile testing of ferromagnetic steels. NDT&E International 41, 184–189 (2008) 15. Naus, H.W.L.: Ferromagnetic Hysteresis and the Effective Field. IEEE Transactions on Magnetics 38(5), 3417–3419 (2002)
Modeling and Performance Analysis of Giant Magnetostrictive Microgripper with Flexure Hinge Qinghua Cao*, Quanguo Lu, Junmei Xi, Jianwu Yan, and Changbao Chu Institute of Micro/nano Actuation and Control, Nanchang Institute of Technology, Nanchang, P.R. China [email protected], [email protected]
Abstract. In order to improve the steady output of micrgripper, the giant magnetostrictive micrgripper with flexure hinge is taken as the research object. Its structure and working principle are presented .the static performance experiments are done and the better linear work domain is found. On the basis of that the dynamic model of the microgripper is established and the formula of the microgripper’s output displacement is deduced. the relationship between the microgripper’s parameters and responses are analyzed and open-loop simulation step is done, The simulation results show the giant magnetostrictive material(GMM) rod damp effects on the response time and its quality has little influence. Keywords: Giant magnetostrictive micrgripper, Flexure hinge, Dynamic model, Open-loop simulation step.
1 Introduction
,
Microgripper[1] fulfils the core role in fine handling micro- parts which can convert other power into mechanical energy. In recent years, the research of the micrgripper are concentrated in two respects with the rapid development of tiny technology : One is the drive mode, for example electrostatic microgripper , thermally driven microgripper [2], piezoelectric driven microgripper [3], shape memory alloy microgripper [4], and vacuum adsorption microgripper, etc. on the other hand, Many studies have been conducted to develop microgripper technology. In this study, the giant magnetostrictive micrgripper with flexure hinge is taken as the research object. The static performance experiments are done and the better linear work domain is found. On the basis of that the dynamic model of the microgripper is established and open-loop simulation step is done.
2 Structure and Static Performance Experiments 2.1 Structure Design of the Microgripper Magnetostrictive microgripper is a new microgripper[5], which is produced by GMM doing work through the stretching deformation of it in changed magnetic field. Fig. 1 shows a conceptual drawing of the microgripper proposed in this study. *
Corresponding author.
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1. palate 2. microgripper jaw 3. JAW 4. uppersuspensionarm 5. suspensionarm 6. linker arm 7. GMM 8. Electromagnetic coil 9. Circular hole 10. Slice 11. Flexure hinge Fig. 1. Conceptual drawing of microgripper
The principle of operation of the proposed microgripper is as follows: firstly, GMM is placed between the microgripper jaw and the suspensionarm, A magnetic circuit is formed through the microgripper jaw , uppersuspensionarm, linker arm, suspensionarm, GMM.When the controlled current is flowing into the electromagnetic coil to produce magnetic field, GMM produces stretching deformation. Secondly, Deformation can promote the microgripper jaw around the flexible hinge towards the direction of palate, so that the JAW produces microdisplacement to clamping objects. 2.2 Static Performance Experiments the PC machine is adopted in the measurement and control system, digital signals which PC generate converted into analog voltage signals by PCI-8333D/A, which input to the controllable constant current source. the coil is driven from current source so that the magnetic field strength around the rod is altered, the GMM rod produces magnetostrictive deformation in order to provide microgripper driving, accordingly,displacement and clamping force of JAW is generated.Experimental system is placed on vibration isolation platform in order to reduce effect of the ground vibration. At the same time, environmental humidity and temperature stability are to meet the requirement of experiment. Experimental In-kind photo is shown in Fig 2.
Fig. 2. Experimental In-kind photo
The controlled current began to increase from 0 to 4A, experimental curve is drawn, which are shows in Fig .3. There is the characteristic of large-time delay of the
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giant magnetostrictive material(GMM) , the linear degrees are relatively poor, to simplify the mathematics model, the better linear work domain for 0.6 ~ 1. 5A is found by the test and analysis.
Fig. 3. Static performance experiments
3 Displacement-Current Modle of the Microgripper 3.1 The Linear Model of GMM Under the environment of steady current, the GMM rod is elongated due to the magnetic field, which generate driving force fq and elastic restoring force fh, Supposed the rod as an ideal elastomer, x is the rod elongation, according to Hooker's theorem, elastic restoring force function fh can be expressed as:
f h = K GMM x
(1)
Where KGMM is the rod stiffness coefficient, From mechanics of materials, function KGMM is defined as:
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E1 A lm
(2)
Where E1 is Young's modulus of the length direction, A is cross-sectional area and lm is the rod length. Neglecting the other force, force diagram is described in Fig. 4.
Fig. 4. Force diagram of GMM
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In the light of d'Alembert's principle, function F can be written as: .
..
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(3)
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+ dH
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(5)
E1
,
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+ d ⋅ H ⋅ lm
(6)
According to Ampere's theorem, the magnetic field around rod is uniform magnetic field, and magnetic field strength at electromagnetic coil center is approximately equal to the average intensity of rod, one can get the following relations:
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(7)
Where Kcoil is the compensatory coefficient of the drived coil. Substituting (7) into (6) and rearranging gives:
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(8)
Substituting (1),(2),(6),(8)into(3), function F can be rewritten as follows:
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. .. E1 AdN i − K gmm x − C gmm x − M gmm x K coil l m
(9)
Where reference [6] is cited, driving force function fq is implemented as:
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E1 ⋅ A ⋅ d ⋅ N I lm
3.2 The Design of Flexure Hinge The structure of Flexible hinge is shown in Figure 5, where t is the minimum thickness of flexible hinge, a = t +2 R-2Rcosθ is infinitesimal thickness, du = d (Rsinθ) is the infinitesimal length, around the z-axis the moment of inertia function[7] Iz=ba3/12.
Modeling and Performance Analysis of Giant Magnetostrictive Microgripper
(a) Structure diagram
241
(b) Infinitesimal geometry
Fig. 5. Analysis of flexible hinge
Supposing deformation of flexible hinge isr pure bending, ignoring angular displacement except the flexible hinge, E2 is Young's modulus of the microgripper, the deflection angle function as follows:
M z (x)dx θm 12M z R cosθ dθ =∫ 3 −θ m z E I ( x) E2b(t + 2R − 2R cosθ ) 2 z
αz = ∫ Here s =
R , function α z can be rewritten as: t
=
∫ θ (t + 2 R − 2R cos θ ) dθ −
3
m
cos θ
θm
12 M z E 2 bR 2
cos θ
θm
12 M z E 2 bR 2
αz =
∫ θ (s + 2 − 2 cos θ ) −
3
m
dθ
Torsional stiffness of flexible hinge function k can be derived as follows:
k=
Mz
αz
=
θm
12∫
−θm
Where f =
=
E2bR2 cosθ
(s + 2 − 2 cosθ )3 cos θ
θm
∫ θ (s + 2 − 2 cos θ ) −
3
m
8 s 4 (2 s + 1 ) tan
dθ
=
E2 bR2 12 f
dθ
θm
2 2 ⎡ (4 s + 1 )2 ⎢1 + (4 s + 1 ) tan 2 θ m ⎤⎥ 2 ⎦ ⎣
(
)
4 s 3 6 s 2 + 3 s + 1 tan
θm
2 ⎡ 2 θ m ⎤ (4 s + 1 ) ⎢1 + (4 s + 1 ) tan 2 ⎥⎦ ⎣ θ ⎞ 12 s 4 (2 s + 1 ) ⎛ arctan ⎜ (4 s + 1 ) tan m ⎟ + 5 2 ⎠ ⎝ (4 s + 1 ) 2
+
2
(10)
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According to principles of Action and Reaction, force of the microgripper received from GMM is equal to the force of microgripper jaw acting on the GMM, F is external force of the flexible hinge, Leverage model simplified from flexible hinge is shown in Fig.6.
Fig. 6. Leverage model (b) simplified from flexible hinge (a)
x , m where m is distance from the rod to the hinge simplied. Stored elastic energy Aθ of 1 2 the flexible hinge can be expressed as: Aθ = kθ , elastic energy Aθ is equal to 2 work done from force F, work function A can be defined as: A = fx , force F can be Because the rod elongation x is very small, the angle of leverage rotation θ =
rewritten again:
F=
kx m2
(11)
Substituting (10),(11) into (9) and rearranging gives: ..
.
M gmm x+ Cgmm x+ (K gmm +
E AdN K )x = 1 i 2 Kcoillm m
(12)
3.3 Displacement of JAW According to leverage shown in Fig.4, one can get the following relations:
y x = h m
(13)
Where h is the distance from JAW to the hinge,y is the displacement of JAW. Substituting (12) into (14) and rearranging gives: .. m . m E AdN m K Mgmm y+ Cgmm y+ (Kgmm + 2 ) y = 1 i h h h m Kcoillm
(14)
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4 Experiments of the Microgripper Laplace transform of (14) is done and rearranging gives:
G(s) =
x(s) = I(s)
E1AdN Kcoillm
(15)
m m m K Mgmms2 + Cgmms+ (Kgmm+ 2 ) h h h m
The relevant parameters of (15) is given and function G (s ) can be rewritten as: G (s) = K
ω n*
*
= 2 . 71 × 10
Where K* is open-loop gain,
2
s 2 + 2 ξ * ω n* s + ω n* −4
×
2
51970 2 s + 2 × 0 . 39 × 51970 s + 51970 2
ξ * is the damp coefficient, ω n*
2
is angular frequency of
the undamped oscillation. The relationship between the microgripper’s parameters and responses are analyzed and open-loop simulation step is done, steps are as follows: firstly, the GMM damp is changed when the other parameters remain, the simulation result is shown in Fig.7. secondly, the GMM quality is changed when the other parameters remain, the simulation result is shown in Fig.8.
Fig. 7. Comparison of the simulation curves with the different damp
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Fig. 8. Comparison of the simulation curves with the different quality
The simulation results show the giant magnetostrictive material(GMM) rod damp effects on the response time and its quality has little influence, At the same time, the overshoot decrease due to the damp increase, while the overshoot iecrease due to the quality increase. Accordingly, the relationship between the microgripper’s designed parameters and responses are found, It is beneficial for the microgripper to optimize parameter.
5 Conclusion In this study, the giant magnetostrictive micrgripper with flexure hinge is taken as the research object. Firstly, due to the hysteresis and nonlinearity of GMM, the better linear work domain is found when the static performance experiments are finished. Secondly, a flexible hinge mechanism to magnify the displacement is prototyped and torsional stiffness are analyzed, with compact structure, small size, motion sensitivity. the dynamic model of the microgripper is established and the formula of the microgripper’s output displacement is deduced. Lastly, open-loop simulation step is finished, The simulation results show the giant magnetostrictive material(GMM) rod damp effects on the response time and its quality has little influence . there lie foundation for follow-up parameter optimized research.
Acknowledgment The authors would like to acknowledge the financial support by the National Natural Science Fund of China (Grant No. 50865008), China Postdoctoral Science Fund (Grant No. 20080431005) and Youth Science Fund of Jiangxi province office of education of China (Grant No.GJJ09611, Grant No. GJJ10633).
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References [1] Anis, Y.H., Mills, J.K., Cleghorn, W.L.: Active microgripper interface used in microassembly of MEMS. In: Canadian Conference on Electrical and Computer Engineering, CCECE 2006, May 2006, pp. 352–354 (2006) [2] Elbuken, C., Lin, G., Ren, C.L., Yavuz, M., Khamesee, M.B.: A monolithic polymeric microgripper with photo-thermal actuation for biomanipulation. In: IEEE International Conference on Mechatronics and Automation, ICMA 2008, pp. 707–711. [3] Nah, S.K., Zhong, Z.W.: A microgripper using piezoelectric actuation for micro-object manipulation. Sensors and Actuators: A 133, 218–224 (2007) [4] Chang, R.J., Lin, Y.C., Shiu, C.C., Hsieh, Y.T.: Development of SMA-actuated microgripper in micro assembly applications. In: 33rd Annual Conference of the IEEE Industrial Electronics Society, IECON 2007, pp. 2886–2891 (2007) [5] Jia, Z., Guo, D.: Theory and Applications of Giant Magnetostrictive Microdisplacement Actuator. Science and Technology Press, Beijing (2008) [6] Cao, Q., Lu, Q., Yan, J., Liu, D.: Design of New Microgripper Based on GMM. In: The 1st International Conference on Mechanic Automation and Control Engineering, June 25-27 (2010)
Non-destructive Measurement of Sugar Content in Chestnuts Using Near-Infrared Spectroscopy* Jie Liu1, Xiaoyu Li1,**, Peiwu Li2, Wei Wang1, Jun Zhang1, Wei Zhou1, and Zhu Zhou1 2
1 College of Engineering, Huazhong Agricultural University, Wuhan, P.R. China Oil Crops Research Institute, Chinese Academy of Agricultural Science, Wuhan, P.R. China [email protected]
Abstract. The chestnut (Castanea) is an important fruit in Europe and Asia. As a highly variable fruit, its quality is graded according to nutrition components, especially according to the sugar content, which are traditionally measured by using chemical methods. However, the traditional methods are time-consuming, laborious, and expensive. Here, we analyzed the sugar content of intact and peeled chestnuts by near-infrared spectroscopy. The spectra of intact and peeled chestnut samples were collected in the wavelength range from 833 nm to 2500 nm. The Sample Set Partitioning based on joint X–Y distances was used when the calibration and validation subsets were partitioned. The predictive models for intact and peeled chestnut samples respectively, were developed using partial least squares (PLS) regression based on the original spectra and the spectra derived from different pretreatments. The PLS models developed from the spectra of peeled samples gave accurate predictions. The correlation coefficient (R2) of the optimized model for calibration set and validation set were 0.90 and 0.86. Although the models established on the spectra of intact samples did not perform excellently, they were still qualified to measure sugar content of the chestnut kernel. The correlation coefficient (R2) of optimized model for calibration set and validation set were 0.89 and 0.59. These results suggested that NIR spectroscopy could be used as a fast and accurate alternative method for the nondestructive evaluation of sugar content in chestnuts during orchard and postharvest processes.
1 Introduction The chestnut is popular in Asia and Europe for its delicious flavor and abundant nutrition. Every year, more than 1,1Mt tons chestnuts were produced all over the world [1, 2]. However, the chestnut is a highly variable species. The nutrition components, flavor and taste are varied according the variety, origin area, cultivation and storage condition [3-5]. Therefore, evaluating the nutrition components accurately, especially the sugar content, plays an important role in determination of the price, the time for * **
This work is supported by Foundation of Ph.D Site in University (20090146110018). Corresponding author, Tel.: +86 027 87282120; Fax: +86 027 87282121. E-mail address: [email protected]
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 246–254, 2011. © IFIP International Federation for Information Processing 2011
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marketing and preservation, the processing methods and the product quality control [6-8]. Recently, the sugar content in chestnuts are determined by using chemical approach, which is destructive, time-consuming, laborious and expensive[4]. Therefore, developing a rapid nondestructive means to analyze the sugar content of chestnuts, especially for intact chestnuts, is critical to the chestnut industry. Near-infrared spectroscopy (NIR) is a fast, simple non-destructive, cost-efficient and environment-friendly measurement method that requires minimal sample preparation. It has been successfully used in the quantitative and qualitative analysis of horticultural crops. Because the near-infrared region related to vibration and combination overtones of the fundamental O–H, C–H and N–H bonds, which are the primary functional groups of sugar (glucose, fructose, sucrose, etc), this technology is powerful in quantitative analysis of this component [9, 10]. Numerous papers have demonstrated the usefulness of NIR in measurement of sugar content of cereal crops, vegetables and fruits [11-14]. Additionally, NIR spectra, with penetration more than 9 mm, can provide adequate information of the core part or the area covered by peel. Tian et al used this technology to predict the firmness of watermelon [15], Han et al applied it to determine the brown heart of pears [16], and Mexis et al obtained the internal properties in packages of walnuts by this means [17]. Recent research also showed that the NIR was employed for detection of moldy chestnuts [18] and for quantitative analysis of targets with peel such as oranges [19], avocados [20], peanuts [21] and intact asparaguses [22]. However, although it is beneficial and meaningful to apply NIR spectroscopy to the nut industry, NIR has not been popularly used for evaluating the quality of nuts, such as chestnuts, walnuts, and hazelnuts. In this investigation, we exploited the feasibility of NIR spectroscopy for evaluating the sugar content of intact and peeled chestnuts to provide an effective method for the chestnut industry. Also, the efficiency and influence of different preprocessing methods on calibration models were compared to identify the optimized model, as well as to provide reference for further research.
2 Materials and Methods 2.1 Fruit Samples 185 chestnut smaples, from MaCheng area (Hubei, China) were used in this study, and the weight of intact chestnuts ranged from 9.26 g to 27.74 g. Considering the chestnut growing property, the samples were representative enough for different growing conditions, maturation and weather at harvest time. The samples were stored under standard refrigeration conditions (0 °C 4 °C, 80% 90% relative humidity, SB/T 10192-1993) for three to four months before experiment tests. The samples were exposed to temperature 26 °C for 2 hours before experimental tests to allow for temperature equilibrium. The experiment was executed in 10 days with same time interval in order to provide models with wide applicability as the change process of chestnut fruit during storage is perplexing.
~
~
2.2 Spectra Collection and Reference Value Determination NIR spectra were acquired by using a VECTOR33 NIR spectrometer (Brucker Optics, Ettlingen, Germany) equipped with fiber optic accessories and were stored on a
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personal computer connected via an AQP card to the spectrometer. The instrument control, parameter setup, spectral acquisition and storage were carried out with the OPUS software (v. 4.0 Brucker Optics, Ettlingen, Germany). The environment temperature was kept at 26 °C and each sample was scanned 64 times, from which an average spectrum was calculated. Spectra were collected in reflectance mode in the range of 833nm~2500nm at 1.25×106 nm and stored as the absorbance mode. To stabilize the light sources, the spectrometer was warmed up for a period of 1 hour prior to measurement. Before the sample measurement, the spectrum of standard background was obtained as the basic reference. Firstly, every sample was scanned with an intact peel. To avoid differences caused by optical path and angle of incidence, the chestnut samples were scanned with their flat side facing the probe and covering the probe completely. Secondly, it was dissected parallel to the flat side and the hemispheric part was set into the sample container to be scanned. For the same reason, the probe was completely covered by the section. After spectra acquisition, the kernel of the sample was taken out for reference value determination according to the Chinese national standard methods. The sugar content was determined by using an enzymatic method and expressed as the percentage of the fresh weight (GB T 5009.7—2003, SAC). 2.3 Data Analysis The sample set partitioning based on joint X–Y distances (SPXY) was performed to partition the calibration and validation subsets at the rate of 3 to 1. Because of its consideration of the variability in both x and y- information, the SPXY was cited as a method that can cover the multidimensional space more effectively in comparison with the randomly sampling (RS) or partitioning schemes based only on x- or y- space alone (such as the Kennard–Stone (KS) algorithm or concentration gradient sampling)[23]. Consequently, this method can be potentially used to improve the performance of the predictive models. Before calibrating the models, four preprocessing methods, namely multiplicative scatter correction (MSC), standard normal variate transformation (SNV), first derivation (FD) and second derivation (SD) were applied to the spectra. These methods can effectively reduce or remove shifts of baseline and superposed peaks, or interferences due to scatter, particle size, and light distance changes [10, 24]. However, they also result in amplification of noises or loss of information. Therefore, the contribution of a preprocessing method to the predictive models depends on the characteristics of the spectra. The partial least square (PLS) regression method was used to establish the predictive models for sugar content. The optimal latent variables were determined by the lowest root mean square error of cross validation (RMSECV) among the calibration set and the models were validated with the independent validation set. The performance of models were evaluated by the correlation coefficient (R2) between predicted values and reference values of the parameters, the root mean square error of calibration (RMSEC) and the root mean and square error of prediction (RMSEP). The higher the R2 is, the better the model performed, while the lower the RMSEC and RMSEP are, the better the model is. All the data analyses were carried out with the aid of Matlab software (V.7.6, Mathworks, Natick, USA) and the PLS models were developed by using the PLS toolbox (V. 5.20, Eigenvector Research, Inc., Wenatchee, USA).
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3 Result and Discussion 3.1 Spectra Configuration, Reference Values, and Subsets Partition Raw spectra of intact and peeled samples are presented in figure 1. It was found that the absorbance spectra of intact samples were scatter over a wide range, while those of the peeled samples fell in a narrow range. The more prominent diversity of peel surface possibly contributed to these differences. However, the two kinds of spectra show similar features over the entire spectra range except for the bands between 833 nm ~ 1053 nm and 2000 nm 2040 nm. The former band mainly reflected the information of color or texture about the sample surface and the later band possibly revealed the features of peel component. Generally, from both the spectra of intact samples and the spectra of peeled samples, characteristic absorption bands associated with sugar can be observed. For example, the dominant peak at around 1450nm was influenced by the first –OH overtone. The weak bands at around 1780nm were mainly attributed to the first sugar-related overtone and the prominent peak around 1160nm was also associated with sugar [25, 26]. Figure 2 shows the raw spectra of a randomly selected sample with and without peel. The difference of reflectance between the two kinds of spectra is obvious, indicating the influence of the peel on the spectrum.
~
Fig. 1. Raw spectra of chestnut samples (Top: the spectra of intact samples; bottom: the spectra of peeled samples.)
Fig. 2. Different spectra of a randomly selected sample acquired with and without peel (1, the raw spectrum of the peeled sample; 2, the raw spectrum of the intact sample).
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The details of the reference data were shown in Table 1. The sugar content of samples was scattered from 6.6% to 14.6%. It is a wide range since approximately 10 % of the fresh weight is sugar normally. According to the SPXY algorithm, three quarters of the samples were chosen to be the calibration set while the rest served as independent validation. From the obvious difference between the spectra acquired in intact and peeled condition, even of a same sample, it is clear that the subset structure for intact and that for peeled chestnuts are different. The statistic descriptions of subsets were also summarized in Table 1. Table 1. Statistic descriptions of subsets partition and reference sugar content Subset
SN
Mean
SD
Max
Min
Intact Calibration
139
9.96
1.79
14.55
6.57
Intact Validation
46
9.32
1.38
12.92
6.58
Peeled Calibration
139
9.86
1.82
14.55
6.57
Peeled Validation
46
9.60
1.37
13.37
6.62
Total 185 9.80 1.72 14.55 6.57 SN : sample number; SD: standard deviation; Max: maximum; Min: minimum.
3.2 Calibration and Validation of Prediction Models for Intact Sample In the entire spectral range, the prediction models based on the raw and pretreated spectra of intact samples were established by PLS regression, respectively. Independent validation sets were used to evaluate the performance of models. Table 2 presents detailed information about the models. It can be found that, the FD model had the highest R2 value of calibration and validation and the lowest RMSEC and RMSEP (0.84, 0.59, 1.12 and 1.32, respectively). Although the SD model had great parameters for calibration, it appeared as an over-fitting one because of the poor result for validation, which indicated the effect of derivation preprocessing in extracting the useful Table 2. Statistics parameters of PLS models for sugar content in intact samples PM NP
Calibration
Validation
R2
RMSEC
R2
RMSEP
0.676
1.287
0.583
1.531
Factors 8
MSC
0.773
1.107
0.597
1.330
9
SNV
0.669
1.300
0.554
1.400
7
FD
0.838
1.116
0.589
1.320
4
SD
0.967
0.445
0.516
1.383
4
PM: Preprocessing method for models; NP: no preprocessing; MSC: multiplicative scatter correction; SNV: standard normal variate transformation; FD: first derivation; SD: second derivation; R2: correlation coefficient; RMSEC: root mean square error of calibration; RMSEP: root mean square error of prediction.
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information in spectra and the result of this method to noise amplification along with the order increasing. The SNV was not a good preprocessing method for intact samples since the model performed worse than the one based on the raw spectra. While the MSC model had same parameters with the model for peeled samples, its latent variables was 9. 3.3 Calibration and Validation of Prediction Models for Peeled Sample The PLS models for peeled samples were calculated in the same way and the results were presented in Table 3. Similar with the results of models for peeled samples, the FD model gave the best performance with 0.91, 0.87, 0.76 and 0.74 as the R2 of calibration, R2 of validation, RMSEC and RMSEP, respectively. The SD model would also be over-fitting because of the unacceptable difference of R2 of calibration and R2 of validation while it had less factor number. Compared with the model based on raw spectra, the MSC and SNV models shown their capability of obtain the relevant information in spectra. However, these two models were not reliable enough because the differences between the R2 of calibration and R2 of validation were unacceptable. It can be seen that, the models based on the spectra of peeled samples performed better than those based on the spectra of intact samples. The influence of peel in spectra acquisition might be the reason. However, their spectral characteristics were similar because the effects of different preprocessing methods followed the same order: the first deviation was the most powerful; the second deviation was the least effective, and the SNV and the MSC performed medium and their results were near to that of the non-preprocessing. The poor performances of MSC and SNV models both for intact and peeled samples shown that the influence of peel to predictive models came more from its obstruction to penetration instead of its surface diversity. Table 3. Statistics parameters of PLS models for sugar content in peeled samples PM
Calibration
Validation
2
2
R
RMSEC
R
RMSEP
Factors
NP
0.505
1.558
0.625
1.112
7
MSC
0.773
1.107
0.597
1.330
3
SNV
0.699
1.278
0.809
0.810
6
FD
0.907
0.761
0.865
0.739
4
SD
0.802
1.084
0.653
1.097
2
PM: Preprocessing method for models; NP: no preprocessing; MSC: multiplicative scatter correction; SNV: standard normal variate transformation; FD: first derivation; SD: second derivation; R2: correlation coefficient; RMSEC: root mean square error of calibration; RMSEP: root mean square error of prediction.
According to Shenk and Westerhaus [27], an R2 value of more than 0.9 indicates excellent quantitative information, a value of between 0.70 and 0.89 means good quantitative information, and a value of between 0.50 and 0.69 is qualified for good
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separation of samples into high, medium and low groups. Therefore, the FD models based on the spectra of samples peeled and intact, were reliable to test the sugar content of chestnuts.
4 Conclusion The present work addressed the assessment of chestnut quality by near-infrared spectroscopy. The presented results demonstrated the potential of NIR spectroscopy in evaluating the sugar content of intact and peeled chestnuts. The correlation coefficients of the optimized models for sugar were 0.90 for peeled samples and 0.83 for intact samples. These results proved that NIR can be used as a nondestructive and rapid means for determining the sugar content of chestnuts with reduced time and labor compared with traditional methods. Further work would be needed to develop more accurate and robust models by selecting sensitive bands, intensifying spectra energy or combining chemometrics methods. Portable or online devices could be developed based on these results to offer information for decisions on harvest, market or process, which will benefit the whole chestnut industry.
Acknowledgement The authors really appreciate the financial support provided by Foundation of Ph.D Site in University (20090146110018) and China Scholarship Council (2008104710). And, we gratefully acknowledges for Prof. Li Peiwu’s guidance and the help of Liu Pei during the spectra acquisition.
References [1] http://faostat.fao.org/site/336/ DesktopDefault.aspx?PageID=336 (2007) [2] Ozcimen, D., Ersoy-Mericboyu, A.: A study on the carbonization of grapeseed and chestnut shell. Fuel Process. Technol. 89(11), 1041–1046 (2008) [3] Feng, Y., Qin, L., Li, F.: Technique of chestnut cultivation. China agricultural University press, Beijing (2007) [4] Pereira-Lorenzo, S., Ramos-Cabrer, A.M., Diaz-Hernandez, M.B., Ciordia-Ara, M., RiosMesa, D.: Chemical composition of chestnut cultivars from Spain. Sci. Horticulturae 107(3), 306–314 (2006) [5] Freinkel, S.: American Chestnut: The Life, Death, and Rebirth of a Perfect Tree. University of California Press, Berkeley (2009) [6] Pena-Mendez, E.M., Hernandez-Suarez, M., Diaz-Romero, C., Rodriguez-Rodriguez, E.: Characterization of various chestnut cultivars by means of chemometrics approach. Food Chem. 107(1), 537–544 (2008) [7] Gao, H., Chang, X.: The storage and process of chestnuts. JinDun Publishing House, Beijing (2004) [8] Sacchetti, G., Pittia, P., Mastrocola, D., Pinnavaia, G.G.: Stability and quality of traditional and innovative chestnut based products, Book Stability and quality of traditional and innovative chestnut based products. Series Stability and quality of traditional and innovative chestnut based products, pp. 63–69 (2005)
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[9] Lu, W.Z., Yuan, H.F., Xu, G.T.: Morden Near Infrared Spectroscopy Analytical Technology. China Petrochemical Press, Beijing (2007) [10] Williams, P., Norris, K. (eds.): Near-Infrared Technology in the Agricultural and Food Industries. American Association of Cereal Chemist (2002) [11] Huang, H.B., Yu, H.Y., Xu, H.R., Ying, Y.B.: Near infrared spectroscopy for on/in-line monitoring of quality in foods and beverages: A review. J. Food Eng. 87(3), 303–313 (2008) [12] Yan, T., Zhao, L., Han, D.: Basement and Application of Near Infrared Spectroscopy Analysis. China Light Industry Press, Beijing (2005) [13] Nicolai, B.M., Beullens, K., Bobelyn, E., Peirs, A., Saeys, W., Theron, K.I., Lammertyn, J.: Nondestructive measurement of fruit and vegetable quality by means of NIR spectroscopy: A review. Postharvest Biol. Technol. 46(2), 99–118 (2007) [14] Ying, Y.B., Liu, Y.D., Fu, X.P.: Sugar content prediction of apple using near-infrared spectroscopy treated by wavelet transform. Spectroscopy and Spectral Analysis 26(1), 63–66 (2006) [15] Tian, H.Q., Ying, Y.B., Lu, H.S., Xu, H.R., Xie, L.J., Fu, X.P., Yu, H.Y.: Study on predicting firmness of watermelon by Vis/NIR diffuse transmittance technique. Spectroscopy and Spectral Analysis 27(6), 1113–1117 (2007) [16] Han, D.H., Tu, R.L., Lu, C., Liu, X.X., Wen, Z.H.: Nondestructive detection of brown core in the Chinese pear ’Yali’ by transmission visible-NIR spectroscopy. Food Control 17(8), 604–608 (2006) [17] Mexis, S.F., Badeka, A.V., Riganakos, K.A., Karakostas, K.X., Kontominas, M.G.: Effect of packaging and storage conditions on quality of shelled walnuts. Food Control 20(8), 743–751 (2009) [18] Liu, J., Li, X., Wang, W., Zhang, J., Zhou, Z., Xiao, W., Zhou, W.: Study of Discrimination of Moldy Chestnut Using Near- Infrared Spectroscopy, Book Study of Discrimination of Moldy Chestnut Using Near- Infrared Spectroscopy. Series Study of Discrimination of Moldy Chestnut Using Near- Infrared Spectroscopy. American Society of Agricultural and Biological Engineers, paper no. 095715 (2009) [19] Tewari, J.C., Dixit, V., Cho, B.K., Malik, K.A.: Determination of origin and sugars of citrus fruits using genetic algorithm, correspondence analysis and partial least square combined with fiber optic NIR spectroscopy. Spectrochim. Acta, Part A 71(3), 1119–1127 (2008) [20] Blakey, R.J., Bower, J.P., Bertling, I.: Influence of water and ABA supply on the ripening pattern of avocado (Persea americana Mill.) fruit and the prediction of water content using Near Infrared Spectroscopy. Postharvest Biol. Technol. 53(1-2), 72–76 (2009) [21] Sundaram, J., Kandala, C.V.K., Butts, C.L., Windham, W.R.: Application of NIR Reflectance Spectroscopy on Determination of Moisture Content of Peanuts: A Non Destructive Analysis Method, Book Application of NIR Reflectance Spectroscopy on Determination of Moisture Content of Peanuts: A Non Destructive Analysis Method, Series Application of NIR Reflectance Spectroscopy on Determination of Moisture Content of Peanuts: A Non Destructive Analysis Method. American Society of Agricultural and Biological Engineers, paper no. 095864 (2009) [22] Flores-Rojas, K., Sanchez, M.T., Perez-Marin, D., Guerrero, J.E., Garrido-Varo, A.: Quantitative assessment of intact green asparagus quality by near infrared spectroscopy. Postharvest Biol. Technol. 52(3), 300–306 (2009) [23] Galvao, R.K.H., Araujo, M.C.U., Jose, G.E., Pontes, M.J.C., Silva, E.C., Saldanha, T.C.B.: A method for calibration and validation subset partitioning. Talanta 67(4), 736– 740 (2005)
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[24] Isaksson, T., Naes, T.: The Effect of Multiplicative Scatter Correction (Msc) and Linearity Improvement in Nir Spectroscopy. Appl. Spectrosc. 42(7), 1273–1284 (1988) [25] Osborne, B.G., Fearn, T., Hindle, P.H.: Food and Beverage Analysis. Longman, Essex (1993) [26] Walsh, K.B., Golic, M., Greensill, C.V.: Sorting of fruit using near infrared spectroscopy: application to a range of fruit and vegetables for soluble solids and dry matter content. J. Near Infrared Spectrosc. 12(3), 141–148 (2004) [27] Shenk, J.S., Westerhaus, M.O.: Calibration the ISI way. In: Davies, A.M.C., Williams, P.C. (eds.) Near Infrared Spectroscopy: The Future Waves. NIR Publications, Chichester (1996)
Nondestructive Testing Technology and Optimization of On-Service Urea Reactor Xiaoling Luo1 and Lei Deng2 1 College of Electromechanical Engineering Qingdao University of Science and Technology Qingdao, P.R. China, 266061 [email protected] 2 College of Electromechanical Engineering Qingdao University of Science and Technology Qingdao, P.R. China, 266061 [email protected]
Abstract. The paper analyses possible types, shapes and locations of defects in a life cycle according to such factors of a urea reactor as material, structure, manufacture approach, work environment, operating medium and failure mode. Then suitable nondestructive testing methods are chosen to test a urea reactor on service on the basis of characteristics of various nondestructive testing methods. And test procedures are optimized which not only ensure urea reactor safety operation, but also reduce test time and minimize plant stand-by loss caused by a test. Keywords: Urea reactor, Defect, Nondestructive testing, Optimization.
1 Introduction A urea reactor is a key equipment in a urea production, it works under high temperature, high pressure and strong corrosion which may bring about defects such as stress corrosion crack and fatigue crack, and even worse, it may cause accidents such as cylinder crack, leakage, or even explosion [1]. Therefore, even if a urea reactor design, manufacture and installation quality totally meets all codes and standards, there can still be some potential safety hazards when process run for a period. It will bring about accidents if not eliminate the failures timely, the common practice to insure urea reactors safe operation is to have a complete detection and mending at regular intervals besides real-time monitor.
2 Urea Reactor Operating Conditions and Characteristics 2.1 Urea Reactor Operating Conditions and Characteristics Operating pressure ≤ 22MPa; Operating temperature ≤ 200 ; Working medium: liquid ammonia, CO2 and methylamine, etc.
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2.2 Working Characteristics High temperature, high pressure and strong corrosion. 2.3 Structural Characteristics Most on-service urea reactors are weld-shrunk multilayered cylinder consisting of liner layer, blankoff plate layer, inner cylinder and layer plate [2]. A urea reactor cylinder has 14 layers with a total thickness of 110mm. Generally liner material is 316L stainless steel with 8mm thickness and blankoff plate material is Q235-A carbon steel with 6mm thickness and inner cylinder material is 16MnR low alloy steel plate with 12mm thickness and layer plate material is 15MnVR with 6 to 8mm thickness.
3 Urea Reactor Regular Defect 3.1 Manufacture Defects There is merely design defect of urea reactor because it is a high pressure vessel and design organizations must have pressure vessel design qualification, besides, weldshrunk multilayered cylinder technology is a proven technique. Defects are mainly caused by a slipshod manufacture process. Manufacturing defects are as follows [3]: (1) That unreasonable structure and discontinuous shape size are easy to result in problems such as stress concentration. (2) Defects such as cracks inside weld joints, incomplete fusions, incomplete penetrations, slag inclusions and gas cavities, etc. (3) Defects such as cracks outside weld joints, incomplete fusions and undercuts, etc. (4) Defect that bead weld layers don’t joint with base materials. (5) Reheat cracks under bead weld layers. 3.2 Application Defects Affected by factors such as inside medium, outside ambient medium, leak detection medium, compressive load and temperature load, urea reactor working environment is severe bad, as a result, defects are brought about as follows: (1) Liner and weld bead corrosion thickness decrease, intercrystalline corrosion, selective corrosion, stress corrosion, crevice corrosion, pitting corrosion and cracks may be accompanied with corrosions mentioned above caused by methylamine. (2) Veneer sheet and weld bead corrosion crack caused by methylamine. (3) Veneer sheet and weld bead stress corrosion cracking caused by outside ambient medium and leak detection medium. (4) Fastener cracks. (5) Cracks in discontinuous shape size surface caused by stress concentration.
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4 NDT Application in a Urea Reactor Periodic Inspection Nondestructive Testing (NDT) detects various materials, components and structures subsurface and external defects, making a judgment and evaluation on defect type, quality, quantity, shape, location, size, distribution and changes according to textural anomaly insides material or changes of heat, sound, electricity and magnetism caused by defects, without damaging the equipment [4]. 4.1 Penetrant Testing Penetrant Testing (PT) is one of the earliest nondestructive testing methods and based on capillarity to reveal open defects on a non-porous material surface. Infiltrate the penetrant into open defects on a workpiece surface, remove the surplus penetrant, and then show defects with the help of developer. Main detect positions and requirements PT is in a urea reactor are as follows: (1) 100% PT on a lining layer soldered joint surfaces. (2) 100% PT on girth joint capping plate corner joint surfaces and connector capping plate corner joint surfaces. (3) 100% PT on joint surfaces between an adapter tube and a weld overlay, an adapter tube and a lining layer as well as internal parts and a lining layer. (4) 100% PT on joint surfaces between an adapter tube and an end plate, an adapter tube and a main body, an adapter tube and an adapter tube. (5) A random PT on a weld overlay focus on appearances where may have problems. Penetrant Testing is accepted according to JB/T 4730-2005 first class, and any surface blowhole is not allowed. 4.2 Magnetic Particle Testing Magnetic Particle Testing (MT) is a kind of NDT which shows defects on the surface of ferro-magnetic material and composition metal based on interaction of magnetic leakage field and magnetic power. MT is widely used to detect cracks, crease, interlining and cinder inclusion on or near ferro-magnetic material surfaces. Main detects position and requirements are as follows: (1) 100% MT on an external surface of a circular joint between a cylinder and an upper or a lower head. (2) No less than 50% MT on a cylindrical shell section longitudinal seam external surface and girth joint between sections. (3) Random inspection on veneer sheets, focus on appearances where may have problems. (4) Kingbolts should be cleaned one by one, damage and cracks should be checked, MT should be done when necessary. Bolt that there are circular cracks on thread and transition section should be replaced. MT is accepted according to JB/T 4730-2005 first class.
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4.3 Ultrasonic Testing Supersonic wave attenuates when travels through a medium, and is reflected back when comes to a interface. This is exactly the principle Ultrasonic Testing (UT) used to detects defects. UT has many advantages, such as high sensitivity, good directive property, good penetrability and fast. UT is widely used in urea reactor test because of an ultrasonic flaw detector has small cubage, light weight, conveniently portable and operate and harmless compared with ray. Main detects position and requirements are as follows: (1) Bead weld UT: no less than 50% UT on a bead weld; test methods and grade follow JB/T 4730-2005, accept with manufacture conditions. (2) Deep girth joint UT: a bead should be planished before a test. The planish bead can be test with different focus normal probes and K1 angle beam probes. UT is accepted according to JB/T 4730-2005 first class. 4.4 Radiographic Testing Radiographic Testing (RT) is a kind of NDT which is based on the difference absorptivity of ray breakthrough testing workpiece (no matter electromagnetic radiation or particle radiation) to show defects inside a workpiece. Main RT used in industry is Xray, γ-ray and neutron-ray, besides, X-ray is the most widely used. Deep girth joint RT can be taken when there are questions after UT or an inspector considers necessary. RT is accepted according to JB/T 4730-2005 second class. 4.5 Acoustic Emission Testing Acoustic Emission (AE) is a physical phenomenon which refers to that once an object suffers shape change or external affection, it will soon releases elastic energy and then generates stress wave. Acoustic Emission Testing (AET) is one of the methods that work through detection device to analysis acoustic emission signal and detect defects by the signal [5]. AET should be taken after agreement from testing unit and end user, AET is accepted following the standard which is made beforehand.
5 Detect Scheme Optimization Exploring Visual testing (VT) is a simplest urea reactor test method, which detects through sight, hear and tactile organs and experiences. It needs other non-destructive testing technologies as supplementary sometimes because VT can only be used in detecting external defects which can be distinguished by a sense organ. MT is used to test a surface and near a surface flaw and has a low requirement of surface finish quality, high defect discovery rate, high flaw detection reliability, low cost and fast working speed. However, it can only be used for a pressure vessel made of ferro-magnetic material. PT is used to test surface split defects and has a high surface finish quality requirement, and flaw detection sensitivity is strongly influenced by defect breadth-depth ratio, defect
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types and operating correct or not, therefore PT is usually used in case where MT cannot work (such as fillet weld). RT is more sensitive to capacity defects rather than to some small cracks, especially those crack defects with a transillumination angle of more than 30 degrees. Nowadays RT is considered to be the most suitable NonDestructive Testing Technology for harmless defects test, but it is of heavy defect detection workload, cost more, and it is harmful to health. UT is of high sensitivity and able to detect extremely harmful planar defects. A lightweight equipment is easy to be operated, so it can make a fast test with a low cost, what’s more, it is harmless to health. But there are certain difficulties about defect qualitative and quantitative; therefore it calls for carefulness and experience. Altogether, optimization non-destructive testing order based on a dangerous defect is VT, MT, PT, UT and RT, according to various non-destructive test applicable occasions and features as well as the theory that a surface defect is much more dangerous than a latent defect.
6 Conclusion In recent years, Non-Destructive Testing Technology has developed rapidly, and some new testing methods have been brought into use, such as metal magnetic memory test, infrared thermography testing, ultrasonic phased array inspection, laser-based non-destructive testing, etc. Non-Destructive Testing Technology has been extensively involved in the development of national economy, and will get faster development and be more widely used in the future.
References [1] Lin, L.H.: Nondestructive Testing Techniques for Pressure Vessels. General Machinery (05), 54–56 (2008) [2] Ding, M.Z.: The urea synthesizes the tower’s corrosion and counterplan. Small Nitrogenous Fertilizer Plant (11), 20–21 (2008) [3] Shi, H.B.: Non-destructive Inspection Technology in Urea Converter Periodic Inspection Application. Petro & Chemical Equipment (01), 23–24 (2009) [4] Wang, Z.M.: General Knowledge of Non-destructive Inspection. Mechanic industry Press, Beijing (2005) [5] GB/T 18182-2000: Acoustic emission examination and evaluation of metallic pressure vessels
Parameters Turning of the Active-Disturbance Rejection Controller Based on RBF Neural Network Baifen Liu1 and Ying Gao2 1
School of Electronic and Electrical Engineering East China Jiaotong University Nanchang, Jiangxi, China [email protected] 2 School of Basic Sciences East China Jiaotong University Nanchang, Jiangxi, China [email protected]
Abstract. The Active-disturbance rejection control (ADRC) has the advantage of strong robustness, anti-interference capability, and it does not rely on the accurate math model of controlled plant. But the parameter self-turning of ADRC isn’t as easy as PID controller because there are more parameters to turn in ADRC. In this paper the parameters are self-turning by the Radial Basis Function (RBF) Neural Network. The results of the simulation indicate that the controller has good anti-interference capability and fast response. The robustness of the system is improved. Keywords: Active-Disturbance Rejection Control (ADRC), Radial Basis Function (RBF), Robustness.
1 Introduction Proportional-integral-derivative (PID) controller, a technique that dates back to 1920s, is still the most widely used control technique in process control although the control hardware has already entered the digital era. To overcome the limitations of PID [1], model based control, such as model predictive control, has been successfully developed. Plenty of linear MPC [2] applications can be found in various industries. The differential geometry method, the inverse system method, the output-tracked method have also been developed in the past years. Though model based control techniques offer many advantages, there are several potential limitations. First, the performance of model based control techniques is heavily dependent on the availability of an accurate process model. The other issue of model based control comes from the state estimation. A highly accurate model often has a large number of state variables, which causes the difficulty in state estimation due to limited number of measurements. In addition, the newly developed moving D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 260–267, 2011. © IFIP International Federation for Information Processing 2011
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horizon estimation techniques just demand a lot of computational effort when using a complicated nonlinear model. Modeling the process and tuning of model based controller are non-trivial tasks. The theory of auto-disturbance rejection control proposed these years is a simple and practical method. It was invented by Professor Han Jingqing who served in Chinese Academy of Sciences. This method does not depend on a precise mathematical model of controlled object. It can estimate and compensate the influences of all internal and external disturbances in real time when system is activated. The control has the advantage of simple algorithm, strong robustness, fast system response and high anti-interference ability. At present, this method has been applied to a number of fields of top science and technology, such as robotics, satellite attitude control, missile flight control, the fire control of tank and the inertia navigation. However, the parameters of ADRC need to turn in these occasions. The study of the parameters self-turning is only at an exploratory stage at home and abroad. RBF Basis function (RBF) neural network has the ability of expressing arbitrary nonlinear mapping, learning and self-adapting, and also has an effective control to complex and uncertain system. This method becomes independent of model. Neural network is applied to fields of technology, and it gains a number of valuable research results. So in this paper, parts of the parameters in ADRC are turned by the RBF neural network. And the simulation results indicate the method is practical.
2 Active-Disturbance Rejection Control Many plants’ model can be simplified as follows:
x
(n)
= f ( x, x,
,x
( n −1)
, t ) + w( t ) + u
(1) ( n −1)
Where, w is external disturbance variable, u is control variable, f ( x , x, , x , t ) is an uncertain plant. For the two-order plant, its standard ADRC controller structure is usually illustrated as Figure 1[3].
Fig. 1. The structure of Active-Disturbance Rejection Controller
According to Figure 1, ADRC controller consists of three main parts: “Transition Process Arranged”, “Nonlinear Feedback” and “Extended-State Observer”.
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2.1 Transition Process Arranged
⎧e = v1 − v0 ⎪ fh = fhan(e, v , r , h ) ⎪ 2 0 ⎨ ⎪v1 = v1 + h ⋅ v2 ⎪⎩v2 = v2 + h ⋅ fh
(2)
Where, v 0 is the control objective, v1 is the track signal of v 0 , fhan(i) is a time optimal integrated function, which detailed expression is described as (3).
⎧ d = r ⋅ h, d 0 = r ⋅ d , y = x1 + h ⋅ x2 ⎪ 2 ⎪ a 0 = d + 8r ⋅ y ⎪ (a − d ) ⎪ ⎧ x2 + 0 sign ( y ), y > d 0 ⎪ 2 ⎪⎪ a = ⎪ ⎨ ⎨ y ⎪ ⎪⎪ x2 + , y ≤ d 0 h ⎪ ⎩ ⎪ ⎧ r ⋅ sign (a ), a > d ⎪ fhan = − ⎪ ⎨ a ⎪ ⎪⎩ r d , a ≤ d ⎪⎩
(3)
2.2 Extended-State Observer (ESO)
⎧e = z1 − y ⎪ z = z + h ⋅ ( z − β e) ⎪1 1 2 01 ⎨ ⎪ z2 = z2 + h ⋅ ( z3 − β 02 ⋅ fal ( e, 0.5, δ ) + b0 u ) ⎪⎩ z3 = z3 + h ⋅ ( − β 03 ⋅ fal (e, 0.25, δ ))
(4)
Where, h is the control cycle. 2.3 Output of Nonlinear Feedback (NF)
⎧e1 = v1 − z1 , e2 = v2 − z 2 , ⎨ ⎩u0 = β1 ⋅ fal (e1 , α1 , δ ) + β 2 ⋅ fal (e2 , α 2 , δ ) ⎧⎪ ε α ⋅ sgn(ε ), ε > δ
fal (ε , α , δ ) = ⎨
⎪⎩ε / δ 1−α , ε ≤ δ
(5)
(6)
Where, the sgn(ε ) is the symbolic function. And the other parameters can be found in [4-5].
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3 ADRC Optimized by RBF Neural Network The structure of ADRC based on RBF neural network control system is shown in Figure 2.
Fig. 2. Schematic of ADRC based on RBF Neural Network
3.1 RBF Neural Network
The RBF neural network is presented by J.Moody and C.Darken in the 1980s which is a feed-forward network with three layers [6-7]. It possesses the capability of local adjustment and can approximate any continuous function in any accuracy. The structure of a typical RBF neural network is shown as Figure 3.
Fig. 3. Schematic of a RBF neural network
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Radial vector of RBF network adopts multivariate Gau-ssian function as radial basis function in this paper.
h j = exp(−
Xi − Cj 2b 2j
) j = 1, 2, … m
(7)
Where h j is the output of hidden unit; b j is the width of hidden unit; C j is the center of hidden units; X i is the output vector; ⋅ is Euclid norm. For an input pattern X i , the output of single output networks are given by m
yout (k ) = ∑ ω j h j
(8)
j =1
Where
ωj
is the weight between the
jth node in the hidden layer and the output unit;
m is the number of hidden unit. 3.2 Control of RBF Neural Network 1) The input and output of controller. RBF neural network can get more information from speed regulating system to adapt the chances of condition with effective measures. The structure of neural network is determined by genetic algorithm. The vector of input is:
X (k ) = [r ( k ), e(k ), e(k ) − e(k −1) / T , ∑ e(k )]T Where r (k ) is the given input;
(9)
∑ e(k ) is the sum of error.
2) The parameters of neural network Array of parameter denotes all the parameters of the hidden unit connected with output layer in RBF network. Applications of RBF network have much difficulty in determining the array and the number of the hidden unit. The selection of hidden unit has a very huge influence on mapping ability and effectiveness of network. If there are too few hidden unit, the network can’t complete the mission of classification and mapping function; if there are too many hidden units, influence generalization ability and learning efficiency. In order to improve the performance of whole system, it is necessary to seek more suitable learning algorithm of RBF network to determine array of parameter; and the number of hidden unit. 3) Target function of neural network J=
1 ( y (k ) − yout (k )) 2 2
Where y (k ) is the output of the target; yout (k ) is the output of the network;
(10)
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4) Self-turning of the parameters in NF Use the gradient descent method to turn the parameters in NLESF: ∂y xc (1) ∂u ∂y Δβ 2 = η e( k ) xc (2) ∂u ∂y Δβ3 = η e( k ) xc(3) ∂u Δβ1 = η e(k )
η
(11)
is the learning rate.
4 Simulation and Analysis In this paper, the simulation model adopts a nonlinear discrete system, whose transfer function is described by rin( k ) = 0.5* sign(sin(0.2π * t )) + (12) 0.25* sign(sin(0.2π * t − π / 2)) Suppose input signal is rin(k ) = 0.5* sign(sin(0.2π * t )) + 0.25* sign(sin(0.2π * t − π / 2))
(13)
We adopt proposed algorithm and controller in the simulation. The outputs of ADRC controller based on RBF identification are shown in Figure 4 . The simulation results are shown the outputs of the identification network can match the output of the closed-loop controlled plant well. The adaptive turning of NF in ADRC controller parameters are shown in Figure 5. At the same time Jacobian information of identification is shown in Figure 6 in simulation. From Figure 7, we can see that the system output trace the reference information well while using ADRC based on BP neural network. And in Figure 8, we can clearly see that the method of PID control cannot trace the reference signal as well as the previous method.
Fig. 4. Output of the target and the network
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Fig. 5. Jacobian information of identification
Fig. 6. Adaptive turning curve of ADRC parameters
Fig. 7. Response of ADRC based on RBF Neural Network
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Fig. 8. Resonse of PID
5 Conclusion Conventional PID controller can hardly work well at different operating condition. A novel controlling method-ADRC based on Radial Basis Function (RBF) Neural Network (NN) is presented in this paper. The controller has advantages of both selflearning capability of neural network and simplicity of ADRC. During the practice, ADRC based on RBF neural network has the superiority such as strong robustness, simple theory. Simulation result shows that the proposed controller has adaptability, strong robustness and satisfactory control performance in the nonlinear and time variable system.
References [1] Suresh Kumar, A., Subba Rao, M., Babu, Y.S.K.: Model reference linear adaptive control of DC motor using fuzzy controller. In: IEEE Region 10th Conference on TENCON 20082008, TENCON 2008, November 19-21, pp. 1–5 (2008) [2] Buchnik, Y., Rabinovici, R.: Speed and position estimation of brushless DC motor in very low speeds. In: Proceedings of 23rd IEEE Convention on Electrical and Electronics Engineers in Israel 2004, pp.317–230 (2004) [3] Pan, Y., Furuta, K.: Variable Structure Control with Sliding Sector for Hybrid Systems. In: International Workshop on Variable Structure Systems, VSS 2006, June 5-7, pp. 286–291 (2006) [4] Ji, Z.-c.,Shen, Y.-x., Xue, H.: Study on the adaptive fuzzy control for brushless DC motor. In: Proceedings of the CSEE 2005, vol. 25(5), pp.104–109 (2005) [5] Ren, y., Zhou, L.-m.: PMSM Control Research Based on Particle Swarm Optimization BP Neural Network. In: International Conference on Cyberworlds 2008, September 22-24, pp. 832–836 (2008) [6] Han, J.: From PID to Active Disturbance Rejection Control. IEEE Transactions on Industrial Electronics 56(3), 900–906 (2009)
Research of Intelligent Gas Detecting System for Coal Mine Chen Hui School of Mechanical and Electrical Engineering, East China Jiaotong University, 330013, Nanchang, China Tel.: 0791-7046122 [email protected]
Abstract. According to statistic data of China in recent years, gas explosion accounted for above 70% in all coal mine accidents. Frequent gas explosion accidents have caused great losses of lives and property. Therefore gas detection and monitoring system is needed to serve as a safety device in coal production. In this paper, an intelligent gas detecting system is designed. This detection instrument adopts SCM AT89S52 as its control hardcore and uses catalytic combustion type gas sensor element MC112 as the sensor for gas (CH4) detecting. The main functions of this system are as follows: monitoring the real-time concentration of CH4 and displaying the concentration value; emitting sound and light alarm signals if the CH4 concentration value is beyond the alarm value inputted by keyboard panel; using serial communication port to transmit data to the host computer above ground. The software debugging and hardware simulating of the system above are also implemented at the same time. Keywords: Data collection, Sensor, Coal mine, Serial communication, SCM.
1 Introduction As the most important source of energy in China, Coal consumption is about 70% of all the energy consumption [1,2]. However, coal mine accident happened frequently in China, lots of people suffered from these disasters. Among all the accident, gas leakage lead to gas explosion is the main reason of these accidents [3,4]. So, it’s significantly important to develop gas monitoring safety system in coal production enterprises. In this paper, a gas detection and monitoring system is presented, its main functions including Real-time monitoring gas concentration, transmitting dynamic safety operation parameters underground coal mine, automatic warning about danger before accident happens and providing useful information on rescuing and evacuating people or equipment to decision makers.
:
2 Overall Design of Gas Detecting System Gas detecting system should meet some specific needs: it can monitoring combustible gas concentration underground coal mine, warning against over standard gas concentration and transmitting real time data to host computer above ground [5, 6]. The gas D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 268–278, 2011. © IFIP International Federation for Information Processing 2011
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detecting system in this paper adopts single-chip microcomputer as control computer; the overall schematic diagram of system is shown in Figure 1. The reason for selecting single-chip microcomputer as a control core is that it possesses advantages of small size, high reliability, low price which made it very suitable to be used in industries of intelligent instrument and real time control field [7].
Fig. 1. Schematic diagram of gas detection system
The operating interface of system is shown in Figure 2. Number at upper right corner shows the default or user-defined gas concentration value, number at upper left corner shows detected gas concentration value. One alarm lamp is equipped. All functions are controlled by keys arranged on the control panel, including POWER key, RESET key, DATA COLLECTION key. Other keys including ten number keys, ADJUST VALUE key and ENTER key are used to change threshold values.
Fig. 2. Operation interface diagram of system
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Basic operating procedures are as follows: Firstly press POWER key, the system initialized. Press DATA COLLECTION key, LED at upper right corner displays the threshold value 1.00; User can customized threshold value by press ADJUST VALUE key and ten number keys, then press ENTER to confirm the change. System starts to detect gas concentration and display these parameters on upper left LED area, at meantime transmit real-time data by RS-485 to host computer above ground.
3 Hardware System Design of Gas Detection System The Hardware architecture of system mainly including main control unit, sensors and signal amplifier circuit, A/D converter module, sound-light alarming circuit, keyboard and display module, serial-communication module. 3.1 Main Control Unit Featured by high integration level, small size and low prices, Single chip microcomputer has been widely used in a broad range of industrial applications including process controlling, data collection, electromechanical integration, intelligent instrument, household appliances and network technology, and significantly improved the degree of technology and automation. Two factors are taken into account here in chip selecting, first one is anti-interference ability, the poor working conditions and complex operating situations in mine tunnel increase the interferences in SCM application systems, so the SCM must have high
Fig. 3. Main control unit
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resistance to outside interference; second one is the performance-price ratio of the SCM. Considering the aforementioned factors, we adopted the AT89S52 developed by ATMEL as main control unit, and the final scheme of main control circuit consists of AT89S52, timer and reset circuit [8,9]. As shown in figure 3. 3.2 Sensors and Signal Amplifying Circuit 3.2.1 Sensor Selection A crucial issue in gas detecting system design is how to select gas sensors. Common gas sensors are metal oxide semiconductor such as tin oxide, zin coxide, titanium oxide and aluminum oxide. Problems encountered with these sensors are lack of flexibility, poor response times and operated at elevated temperature [10]. A new method of ch4 detecting based on infrared techniques was presented in recent years, but it is still in progress and much work should be done before it can be applied to solve the practice problems [11].
Fig. 4. Outside view and internal circuit of MC112
This system adopted catalytic combustion type gas sensor MC112 developed by SUNSTAR group to measure the gas (ch4) concentration. Figure 4 shows the outside view and internal circuit of MC112, table 1 lists the main technology parameters of MC112. MC112 gas detector exploits catalytic combustion principle; the two-arm bridge is comprised of measure and compensate components pairs. When it is exposed to combustible gases, measure components resistance RS increased and transmit output voltage parameter through measuring bridge, the voltage parameter is directly proportional to the gas concentration value. The compensate component works as temperature compensation and reference. Main features of MC112 include good repeatability, work stably, reliability, linear output voltage, and quick response. The mine safety rules stated that if methane gas concentration exceeds 1%, safety system should make an alert, if gas concentration exceeds 2%, all people must evacuate immediately. Since the detecting range of MC112 for low concentration methane is 0%-2%, it is suitable for measuring low concentration methane in the coal mine.
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Table 1. Main technical parameters of MC112
Rated voltage (V)
3.0
Rated current (mA)
@100
1%CH4 1%Butane 1%Hydrogen Linearity (%)
>14 >30 >24 0~5
Response time (90%)
Less than 10 sec.
Renewal time (90%) Application environment Storage environment Size
Less than 30 sec. -20℃~+60℃ <95%RH -30℃~+80℃ <95%RH 10 14 18
Sensitivity (mV)
0.1
3.2.2 Signal Amplifier Circuit It is necessary to amplify the weak electrical signal detected by MC112 (1% gas concentration fluctuation will result in 16mv voltage change). The system adopted AD623 developed by AD Company as the high performance instrumentation amplifier. It has many merits: (1) rail-to-rail voltage output with 3-12v single supply (2) easy to modify signal gain though an external resistor, it will be act as a unit gain without external resistor and signal gain can reach to 1000 with an external resistor; (3)low power consumption, large-scale operation voltage, good linearity, good thermal stability and high reliability. The schematic diagram of signal amplifier circuit is shown in figure 5.
Fig. 5. Signal amplifying circuit
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3.3 A/D Converter Module As shown in Figure 6, this module consists of multiplexer CD4051, sampling holder LF389, A/D converter AD574A[12] and parallel I/O chip 8255A. As a core part, AD574A is a 12-bit successive-approximation A/D converter chip with three-state buffer, its conversion time is about 25μs. AD574A can directly connected to AT89S52 without additional interface logic circuit, with internal high accuracy reference power supply and clock circuit, AD574A can operate normally without external clock source and reference power supply.
Fig. 6. A/D converter module
3.4 Other Modules 3.4.1 Digital Display Module Traditional LCD module is unsuitable in this system because the working environment mainly lies deep in dark coal mine tunnel. LED with soft light should be the alternative. It is suitable for the adverse circumstances under coal mine features by damp-proof, excellence temperature characteristics and long distance visual effects. In this system, a 6-bit LED is adopted to dynamically display the ch4 gas concentration value, with the segment port and bit port connected with PA port and PB port of 8155(1) separately. The schematic diagram of digital displaying circuit is shown in figure 7.
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Fig. 7. Digital displaying circuit
3.4.2 Keyboard Input Module In keyboard input module, we arranged 13 keys including 10 number keys and “Data collection” key, “Enter” key, “reset” key. Adopted opposite direction connect method, PB port and PC port of 8155(2) connected to keyboard’s row circuit and column circuit respectively. The keyboard input module circuit is shown in Figure 8.
Fig. 8. Keyboard Module Circuit
3.4.3 Serial Communications and Sound-Light Alarming Units The serial communications module is shown at the left part in Figure 9, signal of microcontroller is transmitted to host computer above ground by RS-485, and MAX485 is used to convert the voltage. RS-485 is a multi-point two-way half-duplex communication link based on single balanced-wire circuit featured by high noise suppression, high transfer rate, long distance transmission and Wide common-mode range, its
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maximum transfer rate reaches to 10Mbps, maximum cable distance reaches to 1200m[13,14]. The sound-light alarming unit is shown at the right part in Figure 9. As shown in this figure, P21 and P10 of AT89S52 will take control of sound-light alarming unit when the test value of CH4 gas concentration exceeds the preset value.
Fig. 9. Serial Communications and Sound-Light alarming units
4 Software Design of Control System The primary functions of the software control system including system initializing, threshold value setting, methane gas concentration data collecting and displaying, serial communications etc. To achieve the above functions, we developed serial programs using 51 serials microcontroller assemble program language including main program, keyboard scanning program, A/D converter program, alarming program, serial communications program, data display program, system alarming diagnosis program, double-byte multiply program, triple-byte to binary-coded-decimal program and watching dog program. The system is comprised of many modules, Owing to limited space we introduce main program only. The flowchart of main program is shown in Figure 10. Firstly, main program initializing single chip microcomputer’s registers and I/O ports, then scanning keyboard to see if the data collection key is pressed, if no, keep scanning keyboard until data collection key is pressed. When the collection key is pressed down, default threshold value 1.00 is shown on the panel, if user wants to reset threshold value, just press the ADJUST VALUE key to set a new value, and press ENTER key to finish this step. When ENTER key is pressed, system start the operating of data collection and A/D conversion, then transmit the converted data into binary format by calling a subprogram of double-byte multiply. We need three storage units to hold these data because they are 24 bits data in binary format. Next, system will transmit these binary format data into binary-coded-decimal format by calling a subprogram of triple-byte to binary-coded-decimal. In the last step, comparing the value with pre-set threshold value to decide if the system should send an alarm signal. In the meantime,
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Fig. 10. Flowchart of the main program
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these data will be sending to host computer above ground through RS-485 serial communications unit. Still, the system will send a positive pulse to reset the watchdog timer every 1.6 sec. the Crystal Oscillator frequency of the SCM adopted in this system is 12MHZ, with timer/counter TO, working in mode 1(16bit timer/counter), its maximal timing interval is about 66ms, so the system will send a feeding dog signal to watch dog circuit every 66ms.
5 Conclusions In this study, an intelligent gas detecting system is presented. It can be used to real-time monitoring the methane gas concentration underground coal mine. The measuring scope of this system range from zero to 2 percent, the sensitivity of the sensor reach to 0.01 percent. It is equipped with the quick speed and high performance 12-bit A/D converter, the operating environment temperature ranged from -20℃ +70℃. Still this system features with high reliability, easy to operate, high performance-price ratio. In this paper, the total plan and software and hardware design of a gas detecting system are presented, by using Proteus to test hardware circuit and using Keil to test assemble language source program, the simulation test result shows this system is of high accuracy, quick response and is feasible.
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References 1. Li, Y.H.: Analysis on relationship between economic growth and coal consumption. Economic Tribune 458, 52–53 (2009) 2. Luo, Z.: Optimum utilization of coal resources in western region of China. China Mining Magazine 10(1), 36–39 (2001) 3. Yu, B.F.: Handbook of Coal Mine Gas Disaster Prevention and Utilization. China Coal Industry Publishing House (2005) 4. Zhou, J.M.: Causes for 1.25 Extremely Large Methane Explosion in Gengcun Coal Mine and the Preventive Measures. Safety in Coal Mines 32(3), 32–33 (2001) 5. Wang, K., Hao, N.: Conception of Coal Mine Safety Comprehensive Early Warning System. Safety in Coal Mines 39(11), 103–105 (2008) 6. Yan, Y.G., Zhang, L.: Design of Portable Methane Detection Alarm. Alarm. Safety in Coal Mines 39(9), 32–33 (2008) 7. Yu, Y.Q.: Applications of Single-Chip Microcomputer used in the Control System. Publishing House of Electronics Industry (2003) 8. Sun, Y.C., et al.: New Type AT89S52 Serial Single-Chip Microcomputer and Its Application. Tshinghua University Press (2004) 9. Wang, X.Z.: Theory of AT89 serials Single Chip Microcomputer and Interface Technology. Publishing House of Beihang University (2004) 10. Faizah, M.Y.: Room temperature multi gas detection using carbon nanotubes. European Journal of Scientific Research 35(1), 142–149 (2009) 11. Li, W.J., Hu, Y., Li, T.: Detecting System of Methane Based on Infrared Technology. Safety in Coal Mines 39(11), 63–66 (2008)
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12. Zhang, Z.J.: Application of AD574 in Data Acquisition. International Electronic Elements (6), 55–56 (2003) 13. Xie, R.H.: Complete Collection of Serial Communication Technology. Tsinghua University Press (2003) 14. Castro, M., Sebastian, R., Yeves, F., et al.: Well-known serial buses for distributed control of backup power plants RS-485 versus controller area network(CAN)solutions. Industrial Electronics Society 3(5-8), 2381–2386 (2002)
Research of Subway’s Train Control System Based on TCN Qingfeng Ding, Fengping Yang, and Qixin Zhu College of Electrical & Electronic Engineering, East China Jiaotong University, Nanchang, P.R. China [email protected]
Abstract. Contraposing the subway car control equipment being scattered, the subway train controlnetwork system based on TCN RTP is designed. By constructing the virtual network environmentnetwork with simulation software NS2 and writing message data of transmission layer protocols.Through testing train control network communication efficiency, the influent factors of communication efficiency is known.Train control telecommunications devices based on TCN RTP communication function is developed. Using XML technology and JAVA language JDOM analytical mode, the compatible TCCL cross-platform configuration software of other train control communication equipments is designed.Through the train control communications equipment configuration of the basic functions and setting device configuration of network communication operation parameters to the purpose. Keywords: TCN, RTP, Event arbitration, Network simulator.
1 Introduction Train network control system is a set of distributed computer system,winch carries the information of control, test and fault diagnosis by the train’s bus, monitors all trains and cars of related functions [1].The railway signal has been changed. The traditional way is the ground signals to pass traffic command, rules of operation of drivers. At present ,the way is that the information be sending by the line under the ground automatically controls train speed and the car running by the control system in a controlled manner. In order to achieve the coordination of the dispersion trains of equipment in all vehicles,train communication network gradually is developed in the early stage on the basis of serial communication bus. But trains production companies around the world use different train communication network technology in their respective development manufacturers, and the signal system is different.The importing subway train of our country have also used various types of train communication network, such as the Shanghai Pearl Line Metro uses the D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 279–285, 2011. © IFIP International Federation for Information Processing 2011
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WORLDFIP bus and Guangzhou Metro Line 1 uses vehicle bus based a high-level data link control (HDLC) protocol[2-3]. The major cities are being connected the different train’s network. Network control is a way that control scattered train control equipments, so network controlling the control device of train control system is out of natural selection and necessary requirement, which has important theoretical significance and application value to actively promote the localization process of train control technology. This paper mainly reseach the following issues of subway train control system and communications network based on TCN. (1) RTP (Real-Time Protocol) packet transmission and verification.The data communication frequency and message priority between the Multifunction Vehicle Bus (MVB) and Wire Train Bus (WTB) are different, research transmission Methods of three types of real-time information:process data, message data and monitoring data in the TCN network. (2) Train control communications network performance. Setting up the TCN test environment to analyze factors of the network operation performance, such as loss rate of the network node information packet, delay and jitter rates. (3) Achieve train control device configuration capabilities.Select the structure and design of configuration file markup language to complete the basic functions of control equipment, network topology, to achieve device configuration.
2 RTP Communication Modeling RTP communication model uses the publisher / subscriber communication structures. IEC 61375-1 defines the statute of the corresponding abstract model RTP, which services in the train control system. MVB and WTB transmission three types important information of process data, message data and monitoring data, which is a cycle process of data communication mode compared with sporadic transmission message data. The transmission of RTP messages uses by the master scheduling mechanism. General Event uses by the polling way. When more than one device requests to respond, it will collide, then the bus master boots arbitration mechanism. Event arbitration is distinguished by event priority to achieve efficient incident response. Because the frequency of data communication and message priorities between MVB and WTB are different, the paper focuses on the methods to transmit of the three types of real-time information in the TCN network. (1) Messages transmission mapping of RTP model achieve more specific.The application layer protocol data unit is specifically defined as PDU (Protocol Data Unit),which is coded by the presentation layer, then directly map to the data link layer and physical layer.Namely the transport layer and network layer are empty. The purpose of this mapping is to avoid the propagation delay caused by communication stack, thus ensuring the rapid transfer of packets.
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The role of presentation layer is encoding the application layer PDU to fit transmission in the TCN network, RTP message transmission encoding selects using ASN.1 Basic Encoding Rules (BER).The flowchart of codec is shown in Figure 1. Application
ASN.1 Describing Documents
Encode/ Decode Information
ASN.1 Encoder/Decoder Main Funcation
Data Documents
ASN.1 Real-time library
Fig. 1. The flow chart of the ASN.1 Encoder/Decoder
(2) The transmission of RTP messages uses by the master scheduling mechanism. Bus master releases main frame to poll dispatch communication. When multiple devices respond to the message data request ,it will collide and then the bus master starts arbitration mechanism. This recursive algorithm is choosen to realize arbitration address and to complete the multi-device response. Figure 2 below shows for the arbitration process under device address [2].
Fig. 2. Event Arbitration
3 Study on Network Performances In the course of train control equipment, communications and news service in real-time agreements are more important. Though studing the Transport Layer message data,
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write message data layer protocol design,simulate in NS2 (Network Simulator, version2), build a virtual network environment to simulate the configuration of this agreement to make the nodes more freely communicate, and test efficiency of communication, research influencing factors of the communications efficiency. Figure 3 shows for the frame work of tesing bed based on NS2.
Fig. 3. The framework of testing bed based on NS2
This paper studies the following two elements. (1) According to contents of the TCN RTP, design news transport layer protocol by using C + +; use NS2 to build a virtual environment TCN network topology, and add the preparation of the agreement to a virtual network node,test communication of the nodes by using the protocol. (2) Test the running performance of agreement to run. Awk software is used to analyze data on the node, including loss rate of the message data packet, delay and jitter rate, and test the effectiveness of network operations.Comparative analysis is not clearly defined in TCN real-time protocol, including the initiative problem of implicit solution.
4 Train Control Equipment Configuration Function Design TCCL(the Train Control_equirement's Configuration Language) ,on one side, which can describe the basic functions of train control equipment and can access basic information for device plug and play, is the premise equipment interoperability; on the other side , through the configuration file ,can configure the basic functions of train control equipment and set equipment operating parameters to achieve device configuration. 4.1 Configuration Options TCCL file uses XML markup language and the object model involves three levels. The first-level is related with train control systems, describes device capabilities, network topology and the key data format, indicates parameter characteristics of the train control system device.The second level is related with train control equipment.The third related the object by the communication model. Implementing Configurator in TCCL XML parser has the following two common methods [5].
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(1) Using Microsoft's msxml4.dll components. There are usually two ways parsing XML documents. One is the DOM (Document Object Model) ,another method is SAX (Simple API for XML) approach. (2) Using JDOM based on JAVA language. JDOM is a open-source project, which is based on tree structure, using pure JAVA technology implementation on the XML document analysis, formation, and a variety of serialization operation. JDOM services directly JAVA programming. In view of openness and portability features, the research chooses Configurator JDOM as analytical tool. 4.2 Configuration Feature According to the requirements of TCN, the paper design flow chart of train control communications equipment configurator show in Figure 4. In accordance with the above analysis, train control equipment configuration features are included in the following parts [6]. (1) Type information into train control equipment, documents, check whether the configurator database with the corresponding device type information, and if not, suggest new types information into devices; If already have, then prompte whether the need compare between new and old files after import, or directly covering. (2) TCCL Configurator import information file ,then first verify the legitimacy of the file. Verify the legality including three main elements.First, XML syntax validation, whether the XML file configuration accord to file format. Second, TCCL syntax verification, testing whether the configuration information file TCN given specifications; third,verify the device type, testing configuration information file if they meet specified type of device capabilities. If the detect is inconsistent with some of the actual situation,then give warning. (3) Configurator pre-generate configuration information of a particular type of train control device according to device type information files, parse input information stratification into the corresponding information object according to the information model.In the configuration, each object is available separately edited by the configuration which check the necessary restrictions; configurator can create the configuration information file of entirety train control devices according to all the configuration information of each train control device, and can be exported as needed. TCN configuration tool parses the input configuration information into the corresponding information object based on TCN information model, then reflect in the configuration interface; which edits each object and realizes a wide variety response constraints.The final configuration complete and then export TCCL file.
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Fig. 4. Flow chart of configurator operation
5 Conclusion With the rapid development of high-speed railway in China, TCN in the electric multiple unit (EMU) also be applied gradually, train network control systems network architecture of China's CRH1, CRH3 developed and manufactured use the TCN standard.The widely using of TCN offers localization process of train control system a broad market prospect. At the first of the paper, design configuration files of the train control system; then ,establish communication characteristics of the object model according TCN RTP, using the NS2 construct test TCN network environment; finally, complete communications network transmission verification.
Acknowledgement The work described in this paper has been supported by National Natural Science Foundation of China (60964004) and Foundation of JiangXi Educational Committee (GJJ09203) and Foundation of East China Jiaotong University (09DQ03).
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References [1] Wang, L.: Analysis and Study on Train Network Control System. Xi’Nan Jiaotong University Master thesis (2008) (in Chinese) [2] IEC61357-1-1999, Part 1: Train Communication Network [3] Ye, H.: Research and Realization of Subway Train Communication Network. Beijing Jiaotong University Master thesis (2009) (in chinese) [4] Zeng, X.: Train control system with high autonomous property. In: The IAS_ TED International Conference on Intelligent Systems and Control (ISC 2005), pp. 204–210. ACTA Press, Cambrige (2005) [5] IEEE Standard for Communication Based Train Control system(CBTC) performance and Functional Requirements. IEEE Std1474.1-1999. [6] Lin, Z.-m., Jiang, S.-l.: Design and achievement of configuration tools based on SCL model. Power System Protection and Control 37(12), 82–85 (2009) (in Chinese) [7] Lu, F., Song, M.-m., Li, X.-l., et al.: Event-Based Control Technology and the Application in Subway Train Operation. China Railway Science 27(4), 106–112 (2006) (in Chinese) [8] Zeng, R., Lu, X.-y.: Control and TCN of the first domestic AC drive metro train. Electric Drive For Locomotives 3, 35–38 (2004) (in Chinese) [9] Lang, Z.-t., Zeng, X.-q.: Rail Traffic Signal Control. Tongji Unversity Press, Shanghai (2006) (in Chinese)
Shape Detection for Impeller Blades by Non-contact Coordinate Measuring Machine Shimin Luo School of Railway Tracks and Transportation, East China Jiaotong University, Nanchang, P.R. China
Abstract. The impeller blades are very important and precise parts in turbine, but they can be worn and deformed easily. In this paper, we present a novel approach to detect the shape of the impeller blades. The proposed approach is to compare the designed 3D model of the impeller blades with the virtual 3D model of the tested part which is reconstructed by non-contact coordinate measuring machine. The non-contact coordinate measuring machine measures an object with optical triangulation, and then we can reconstruct a virtual 3D model for the part. In contrast to previous approaches which detect the parts with complex surface, the proposed shape detection approach is scatheless and reliable. Experimental results also show that our approach gets the shape of the tested part precisely and describes the deformed condition clearly. Keywords: Impeller blade, Non-contact coordinate measuring machine, Shape detection, Optical triangulation, Complex surface, 3D reconstruction.
1 Introduction An impeller is a rotor inside a tube or conduit used to increase the pressure and flow of a fluid. It is the rotating component of a centrifugal pump, usually made of iron, steel, bronze, brass, aluminum or plastic, which transfers energy to the fluid. As an important part of the impeller, the impeller blade directly contacts the fluid and mixes up the fluid so that it might be worn and deformed easily. But how to detect an impeller blade with complex surface is a difficult problem to be addressed. In reverse engineering, the noncontact coordinate measuring approaches based on laser triangulation measurement principle use multiple views of cameras to get the depth information of the object [1-3]. The object to be tested can be measured rapidly and precisely without any damage. In recent years, this issues that how to measure object with complex surface becomes one of the hottest questions to be solved in computer vision fields and reverse engineering fields. In this paper, we exploit one of the noncontact coordinate measuring approaches, that is binocular vision measurement, to reconstruct the virtual 3D model for the impeller blade. By comparing the designed 3D model with the virtual 3D model of the impeller blades, we can detect the shape change of the part to be tested. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 286–293, 2011. © IFIP International Federation for Information Processing 2011
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The rest of the paper is organized as follows. Section 2 describes how to get the 3D points cloud of the tested object by the binocular vision measurement. Reconstructing the 3D model of the impeller blades from the point cloud data is introduced in Section 3. Section 4 presents the comparing process. Finally, Section 5 gives the conclusion.
2 Tested Part Digitalization The basic principle of binocular vision measurement is to use two cameras from different views to take pictures for the tested part, extract a series of central image pixels projected by the linear laser, and pair them in the corresponding images according to stereo matching, finally acquire the 3D coordinate values by pinhole model. 2.1 Camera Calibration Camera calibration is a process that obtains the internal and external parameters of the CCD cameras, which aim at establishing a mathematical relationship between the 3D world coordinate system with the 2D image coordinate system. According to the pinhole model, we can transform from the 3D world coordinate system to the 2D image coordinate system by the following four steps [4]: Transform from object space coordinate system to camera coordinate system; The pinhole perspective transformation of transforming from camera coordinate system to 2D image coordinate system; The distortion model that considered the first order distortion; Transform from the actual image coordinate system to the image coordinate system. Finally, we can map the spatial point P with 3D coordinate values x, y, z to the image pixel with 2D image coordinate values u, v by Formula (1):
ªu º s «« v »» «¬1 »¼
ª m11 m12 «m « 21 m22 «¬m31 m32
m13 m23 m33
m14 º ª x º m24 »» « y » « » m34 »¼ «¬ z »¼
(1)
where x, y, z is the coordinate values to be solved; u, v is the image values; and s, mi,j (i = 1, 2, 3; j = 1, 2, 3, 4) is the camera parameters that can be got by the two-step camera calibration approach proposed by Tsai R Y [5-6]. 2.2 Laser Stripe Images Processing Noise reduction: The variability of the ambient light and the inside and outside noises produced by cameras lead to the laser stripe images contain a great deal of random noises, so the target features become dimness, therefore the quality of the 2D laser stripe images become worse, which affect the image segmentation, image thinning and
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image matching. Thus we need filtering algorithm to improve the quality of the images, Gaussian filtering algorithm and median filtering algorithm both can remove the noise points of the laser stripe images effetely, here one of them can be exploited in this situation. Image segmentation: Image segmentation refers to the process that separate the target features from the background. In binocular vision measurement, the target parts of images are the laser stripe. Because the topology position of the laser strip is very important, and the gray information of the laser stripe is insignificant. So we can use image threshold segmentation algorithm to extract the image positions of the laser stripe. According to the intensity of the ambient light and light produced by the laser, the image threshold segmentation algorithm sets a threshold and describes the pixels that gray value is larger than the threshold with white pixel, also describes the pixels that gray value is smaller than the threshold with black pixel. After image segmentation, we can transform a gray image into a white-black image. Laser stripe thinning: Since the projection width of the laser stripe on the images is about 1mm, the target laser stripe at each image row after noise reduction and image segmentation occupies more than one pixel, so we need thin the laser stripe. The aim of laser stripe thinning is to transform the projection of the laser stripe to single pixel at each row. The thinning algorithm must guarantee the geometry and topology property of the laser stripe remain unchanged. The gravity central algorithm is often used to get the single pixel laser stripe. Stereo matching: In binocular vision measurement, in order to obtain the 3D coordinate values of the projection point on the laser stripe, we need to pair the pixel points on the two corresponding laser stripe in the left and right images which are taken by the two cameras at the same time, that is, match one pixel point on the laser stripe in the left image with one of the pixel points on the laser stripe in the right image. The matching algorithm must comply with the following principles: the unique constraint, the continuity constraint, the compatibility constraint, the epipolar constraint, and the order of consistency constraints. The epipolar constraint define the matching pixel points in the right image of a pixel point in left image must be on a specific lines called epipolar line. This constraint greatly reduces the number of pixel points to be verified, and the searching domains are transforming from 2D area to 1D area. After the above digital image processing, we can extract the information of the left and right images to series of paired matching pixel points (, ), which facilitate the subsequent calculations [7]. 2.3 Mathematical Model Establishment The Formula (2), and (3) are established after we push the coordinate values of the paired pixel points into the Formula (1) respectively and eliminate the unknown parameters. Actually Formula (2) represents a line that is start with the left camera center to the pixel point (uL, vL) on the left image, while Formula (3) represents a line that is start with the right camera center to the pixel point (uR, vR) on the right image.
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L L L − m12L ) y + (u Lm33 − m13L ) z = m14L − u Lm34 (u LmL − mL ) x + (u L m32 { L L31 11 L L L L L L L − m22 − m23 − u Lm34 (u m31 − m21 )x + (u Lm32 ) y + (u Lm33 )z = m24
(2)
R R R (u RmR − mR ) x + (u R m32 − m12R ) y + (u R m33 − m13R ) z = m14R − u Rm34 { R R31 11 R R R R R R R R R R (u m31 − m21) x + (u m32 − m22 ) y + (u m33 − m23 ) z = m24 − u m34
(3)
In order to get the coordinate values x, y, z of the 3D point, we solve the unified equation of Formula (2) and (3). If the two lines intersect, the intersection point of the two lines is exploited to calculate the 3D point. If the two lines may not intersect, we define the approximate intersection as the point which is closest to the two lines. More precisely, whether two lines intersect or not, we define the approximate intersection as the point P which minimizes the sum of the square distances to both lines [8], as shown in Figure 1.
Q1
P1
L1
P P2
Q2
L2
Fig. 1. The mathematical model of calculating the 3D points
2.4 The Precision of Reconstruction To measure the reconstruction precision of the binocular vision measurement, we design an experiment to get the center coordinates of the four tangent circles.
y
1
2
3
4
x
Fig. 2. The four circle centre is used to test the reconstructed precision
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We set the centre of the four circle centers as the world coordinate system centre, and make use of the above mathematical model to solve the coordinate values of the four circle centers. As the theoretical values of the coordinate values of the four circle centers is already known, we can get the measure precision by comparison the actual values with the theoretical values of the circle centers. The four circles are shown as Figure 2, and the measurement precision is given as Table I. From Table I, we conclude that the measurement accuracy is within 0.05mm; and this precision can satisfy with the need of industry. Table 1. The reconstruction precision for the four circle centre
x
y
z
-30.0
30.0
0.0
-30.023
30.003
0.040
30.0
30.0
0.0
29.966
30.009
0.067
-30.0
-30.0
0.0
-30.017
-30.004
-0.124
30.0
-30.0
0
30.001
-30.017
0.042
1
2
3
4
Paired image coordinate values ( <123.3, 132.0>, <184.4, 111.4>)
( <121.5, 194.3>, <184.3, 179.2>)
( <367.3, 131.5>, <377.3, 373.6>)
( <366.0, 197.8>, <437.0, 117.9>)
Distance
Distortion
42.426
0
42.445
0.019
42.426
0
42.409
-0.017
42.426
0
42.442
0.016
42.426
0
42.439
0.013
3 The Cloud Data Post-processing We get a lot of point cloud after digitizing the tested part of the impeller blades with the binocular vision measurement described in the previous section, which is a dense collection of surface samples of the impeller blades. We can deal the point cloud of the impeller blades with a dot-curve-surface-based surface reconstructed approach in order to get a visual CAD model [9-10]. First, we can obtain a full outline of the tested part through eliminating point cloud noise, merging the point cloud from different views. Secondarily, by sampling the point cloud to a certain percentage and cutting the section cross the cloud point, we can get a series of 3D-spline curse. After smoothing the 3D-spline curse, we make use of them to regenerate a satisfactory watertight surface by blending the surfaces. Finally, we materialize the surface model of the impeller blades and get the visual 3D model for the tested impeller blades. Notice that the above steps may have to do repeatedly. If we do not satisfied with the final reconstructed model, we must return to the previous step and redo it. The point cloud, curse model, and 3D model of the impeller blades are shown as Figure 3, 4, 5 respectively.
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Fig. 3. The point cloud for the impeller blades to be tested
Fig. 4. The 3D-spline curse of the impeller blades to be tested
Fig. 5. The visual CAD model for impeller blades to be tested
4 Comparisons After the 3D visual model of the tested part are reconstructed, we compare the 3D visual model with the designed 3D model that is already exist at the stage of part designing.
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The PRO/ENGINEERING commercial software can be exploited to compare the two 3D model of the part to be tested. Finally, we can get the surface deformation condition for the impeller blades, as shown in Figure 6, which describe different degrees of surface deformation with different colors.
Fig. 6. The surface deformation condition for the impeller blades
5 Conclusions In this paper, we propose a novel approach to detect the shape deformation condition for the impeller blades by comparing the designed 3D model with the virtual 3D model of the tested part that is reconstructed by non-contact coordinate measuring machine. In contrast to previous approaches which detect the parts with complex surface, the experimental results show our approach is scatheless and reliable.
References 1. Snavely, N., Seitz, S.M., Szeliski, R., Photo Tourism: Exploring image collections in 3D. ACM Transactions on Graphics (Proceedings of SIGGRAPH 2006) (2006) 2. Bradski, G., Kaehler, A.: Learning OpenCV: Computer Vision with the OpenCV Library, p. 32. O’Reilly Media, Inc., Sebastopol (2008) 3. Atcheson, B., Ihrke, I., Heidrich, W., Tevs, A., Bradley, D., Magnor, M., Seidel, H.-P.: Time-resolved 3d capture of non-stationary gas flows. ACM Transactions on Graphics (Proc.SIGGRAPH Asia) 27(5), article 132. 78 (2008) 4. Hirsch, M., Lanman, D., Holtzman, H., Raskar, R.: BiDi Screen: A Thin, Depth-Sensing LCD for 3D Interaction using Light Fields. In: ACM Transactions on Graphics (SIGGRAPH Asia 2009), Yokohama, Japan (December 2009) 5. Tsai, R.Y.: A Versatile Camera Calibration Technique for High-Accuracy 3D MachineVision Metrology Using Off-the-Shelf TV Cameras and Lenses. IEEE Journal of Robotics and Automation RA-3(4) (August 1987) 6. Zhang, Z.: Flexible camera calibration by viewing a plane from unknown orientations. In: International Conference on Computer Vision (ICCV), p. 40 (1999)
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7. Luo, S.-m., Li, M.-x.: Research on How to Get Object’s 3D Coordinate on Two CCD Camera Measure System. Computer Engineering and Design 27, 3622–3624 (2006) (in Chinese) 8. Shapiro, L.G., Stockman, G.C.: Computer Vision. Prentice Hall, Englewood Cliffs (2001) 9. Radeva, P., Toledo, R., Von Land, C., Villanueva, J.: 3-D Vessel Reconstruction from Biplane Angiograms Using Snakes. Comput. Cardiol. 25, 773–776 (1998) 10. Cañero, C., Radeva, P., Toledo, R., Villanueva, J., Mauri, J.: 3-D Curve Reconstruction by Biplane Snakes. In: Proc. ICPR, vol. 4, pp. 563–566 (2000)
Simulation of Road Surface Roughness Based on the Piecewise Fractal Function Zhixiong Lu1, Lanying Zhao2, Xiaoqin Li1, and Jun Yuan1 1
Engineering Collage, Nanjing Agricultural University. Nanjing, 210031, Nanjing, Chinese 2 Institute of mechanical engineering, Dalian Ocean University, 116023, Dalian, Chinese [email protected]
Abstract. The fractal interpolation theory was used to the research of road surface roughness, and its simulating method was proposed through the piecewise fractal model. The fractal interpolation model was established for the actual road surface roughness, its influential factors and their laws of influencing were also analyzed, and then the model accuracy was confirmed by the fractal parameters and the traditional parameters. The research indicated that the simulated parameters of road surface in different resolutions and the traditional parameters can keep better consistency with the actual road surface. The contraction factor and the road surface sampling resolution are main influential factors of the model. The contraction factor’s selection decided directly the fractal dimension of the simulated road and the simulated precision reduced with the decrease of sample resolution at the same time. In fact, this method is able to obtain a better simulation results, as long as the sample resolution was restrained on the scaleless range of road surface roughness.
,
Keywords: Road surface roughness, Piecewise Fractal model, Contraction factor, Scaleless range.
1 Introduction Road surface longitudinal elevation change is a non-stationary random process with multi-scale features. Therefore road roughness resolution, measured by instrument with a certain resolution, reflects the roughness in the limited level rather than completely and really, which manifests scale correlation of road roughness. Obviously, statistical characterization parameters have certain deviation, when the data was collected by road roughness testers with different resolution, and this deviation will affect the evaluation on road surface roughness and the accuracy of analysis on vehicle vibration response. But all these questions will be solved, if the limited test data can be used to simulate a more precise road vertical elevation. At present, roughness testers collect longitudinal elevation data of road surface along the vehicles travel direction, which is in certain sampling interval. So the resolution cannot be high enough to meet the require mends achieve of line survey, and D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 294–305, 2011. © IFIP International Federation for Information Processing 2011
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the smooth curves, fitted by data tested directly or obtained by the traditional interpolation methods (the Lagrange interpolation, transect interpolation and so on), have good fitting effect, but can not characterize self-similar surface roughness characteristics and fine structure. In this paper, fractal interpolating method was introduced to simulate road roughness with fractal characteristics, and simulative results were verified and analyzed in detail.
2 Paper Preparation 2.1 Self-affine Fractal Interpolation The basis of fractal interpolation theory is iteration function systems (IFS).IFS consists of a set of limited contraction mapping family on a complete metric space ( Wi X→X i= 1 2 … N) and the corresponding contraction factor Si [0,1]. Denoted {X Wi i= 1 2 … N}, the contraction factor S= max{Si, i= 1, 2, …, N}. Fractal interpolation actually constructed a iteration function system, the attractor is the graphical of interpolation function. To the two-dimensional discrete 2 data{ xi,yi i=0 1 … N} R , fractal interpolation function is a continuous function f(x),x [x0 xn]→R,which interpolated to { xi,yi i=0 1 … N}, and for each i, function f(x) meet with f(xi)= yi , the graph is attractors of a doublecurved iterated function system. 2 By constructed a iterated function system {R Wi i= 1 2 … N} which attractor is equal to the graph of interpolation f(x), its constructed method as follows: 2 2 suppose each of iterated function systems Wi is the affine transformation Wi R →R , then
:
, ,, , ; , ,, ,
∈
( ), , , , ∈ ∈ ,
( ), , , ,
: , ,, ,
⎛ x ⎞ ⎛ ai 0 ⎞ ⎛ x ⎞ ⎛ ei ⎞ Wi ⎜ ⎟ = ⎜ ⎟⎜ ⎟ + ⎜ ⎟ ⎝ y ⎠ ⎝ ci di ⎠ ⎝ y ⎠ ⎝ fi ⎠ , i= 1 2 … N
,, ,
:
(1)
And satisfy the conditions:
⎛ x0 ⎞ ⎛ xi −1 ⎞ Wi ⎜ ⎟ = ⎜ ⎟ ⎝ y0 ⎠ ⎝ yi −1 ⎠
,
⎛ xn ⎞ ⎛ xi ⎞ Wi ⎜ ⎟ = ⎜ ⎟ ⎝ yn ⎠ ⎝ yi ⎠
,i= 1,2,…,N
(2)
ai , ci , di , ei , f i is the real coefficients to determine an affine transformation, by (2) formula to determine the following four linear equations.
⎧ ai x0 + ei = xi −1 ⎪a x + e = x ⎪ i n i i ⎨ ⎪ci x0 + di y0 + f i = yi −1 ⎪⎩ci xn + di yn + fi = yi
(3)
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Under the constrained condition, here given only four equations, however, five variables, so there is a free variable, generally take di as the free variable and call it the
( ,, , )
vertical scale factor, limited 0≤| di |≤1 i=0 1 … N , which is determined by the property of the affine transform. Here let di=0,make the iteration function system Wi always map the line which parallel to the y-axis still to the line which parallel to the y-axis. Then di express the transform proportion. If di =0, gain the piecewise linear interpolation function. When
di is arbitrary, combination of the above formula,
the other factors of the iterated function system can be derived, as follows:
ai = ( xi − xi −1 ) /( xn − x0 )
(4)
ci = ( yi − yi −1 ) /( xn − x0 ) − di ( yn − y0 ) /( xn − x0 )
(5)
ei = ( xn xi −1 − x0 xi ) /( xn − x0 )
(6)
f i = ( xn yi −1 − x0 yi ) /( xn − x0 ) − di ( xn y0 − x0 yn ) /( xn − x0 )
(7)
Barnsley[1], etc, who have prove, IFS which constructed by this method always have displacement attractor, which must be a continuous function graphics, and also through the interpolation points, this continuous function is the fractal interpolation functions. 2.2 Recurrent Fractal Interpolation Piecewise linear fractal interpolation method is the promotion of linear fractal interpolation. The basic idea is :put the original curve into several paragraphs, which equal or sub-ranges coordinates along the x-axis direction, or several consecutive interpolation points can be put in a group, then each piece of curve according to above fractal interpolation methods get fitting curve[2]. Piecewise fractal interpolation is a new fitting method of data, change its parameters, can get the interpolation curve with different dimensions, generated curve in each segment have an independent self-similarity and fractal dimension.
3 The Algorithm of Vertical Scale Factor Based on constructed curve on fractal interpolation function, fractal dimension D is determined by vertical scale factor di . If known data { xi,yi ; i=0,1,…,n} isn’t
( ) n
collinear, then, D ‘s value is the only solution of equation
∑| d i =1
i
|ai D −1 = 1 ; if inter-
polation points collinear, D=1; under the conditions of 0≤| di |≤1, appropriately select
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di , make D arbitrarily close to 2. however, in the linear fractal interpolation computations, given random the vertical scale factor d i ’ values, it is difficult to make the fractal curve by interpolation more accurately approximate to the real curve or discrete points. According to the principles of above fractal interpolation, be given a set of d i ’values for each, an iterated function system can be completely determined, this iterated function system attractor image is the interpolation image through the known points, how to choose the optimal vertical scale factor to control the shape of the fractal curve, make it possible approximate to the original objective function or discrete data points, which is called the inverse problem of fractal interpolation[3]. Determination of the optimal di value is difficult, Mazel and Hayes[4] give the geometric and analytical methods by using fractal interpolation function to fit discrete data, The geometric and analytical methods is the classic algorithm to calculate vertical scale factor. This paper use particle swarm optimal algorithm to achieve the optimization of vertical scale factor.
4 Fractal Interpolation of Road Surface Roughness As to collected original elevation data of road roughness in the form of discrete points, usually record data by directly connect or traditional interpolation method, then calculate the corresponding deviation index, such as the root mean square, power spectral density and the international roughness index, because of road testing instrument resolution, the evaluation results only reflect the roughness of some cases. In the case of retention measured discrete data, it is the purpose of fractal interpolation of the road roughness original elevation discrete data which obtain the road roughness information between the sampling points, make the fractal interpolation curve far more approximation to the actual road longitudinal curve. According to preliminary studies, we know that road roughness has obvious fractal characteristics. Compared to several thousand kilometers road surface, the longitudinal elevation data to evaluate the road roughness be collected by surface detection equipment, which be limited by hard disk storage space of the detection equipment, usually only a small part of road data, therefore, on the research that the road roughness data may not have the self-affine properties or similar self-affine properties, fractal interpolation on the data may produce large errors[5,6]. Therefore, we simulated the road roughness elevation data adapting piecewise fractal interpolation method. 4.1 Fractal Interpolation Simulation of Road Roughness In this paper, vertical elevation data of asphalt concrete road surface roughness is the object of the study, experimental data collected is the sequence of discrete points:
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{(n,yn), n=0,1,…,N}, N is the sampling points, sampling interval of instrument is 0.16m (resolution), 1024 data points is obtained, then the sample length is 1024 * 0.16 = 163.84m. The measured data were displayed in figure 1. In this sample paragraph, points were taken in every 20 point and interval 3.2m, where low-resolution data (figure 2) is obtained.
Fig. 1. The measured road surface with high resolution
Fig. 2. The measured road surface with low resolution
According to the fractal interpolation theory and the vertical scale factor values estimated by analytic method, the result that high-resolution and low resolution data in Figure 2 is sub-fractal interpolated is shown in Figure 3, the algorithm procedure is implemented by MATLAB7.0.
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a)
b) Fig. 3. The fractal interpolation road surfaces: a) Interpolation of low-resolution data1, b) Interpolation of low-resolution data2
4.2 Validity of Fractal Interpolation In order to test the validity of the results of fractal interpolation, the curves of the characterization of road roughness parameters(root mean square deviation of profile, fractal dimension,) showed in Figure 1 and Figure 3 is calculated and the values is shown in Table 1, in which D is calculated by root mean square method. Fractal characteristics of curve of the original data and simulation of fractal interpolation were compared in Figure 4.
Table 1. The values of several characterizing parameters of measured and interpolated road surface
parameter Rq D
Measured road surface 1.6606 1.6298
data1 Simulated road surface 1.6048 1.6174
Measured road surface 3.1184 1.4732
data2 Simulated road surface 3.0877 1.4726
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Fig. 4. Comparison of primal data and interpolation curve
Comparison with fractal characteristics of curve of the original data and simulation of fractal interpolation in Figure 4 can be found: (1) scaling law relation between simulation curve obtained in the first interpolation interval scale in Figure 4 a) with the original data has crossover phenomenon. It is known by calculating the number of dimensions : the fractal dimensions are still relatively close, both of which fractal error is 0.76%; Scaling law relation between simulation curve obtained in the first interpolation interval scale in Figure 4 b) with the original data is very close. This could explain that the simulation of surface roughness by the fractal interpolation function can be appreciatively simulated with the original data, self-similarity. (2) Time-domain characterization (root mean square deviation of profile parameters) of fractal interpolation curve and the measured road roughness curve are very close, indicating the two have good statistical self-similarity. The above two points can determine that fractal characteristics simulation of road roughness by the fractal interpolation function is feasible. Compared with the measured surface and the interpolated surface graphics in Figure 1 and Figure 3 and the corresponding characterization parameters in table 1, it can be seen that representation parameter values of the measured fractal interpolation curve and surface roughness data graph is very close, both of which are very good Statistical self-similarity, indicating that sub-fractal interpolation function with the road roughness of fractal characteristics is a sound result.
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4.3 The Accuracy Factor Analyses Affecting the Fractal Interpolation of Road Surface Roughness Vertical scale factor is the key factor to control the accuracy of the fractal interpolation, which has been described in principle. At the same time, changes in the number of iterations, the size of the sampling point interval (resolution) and sampling length also affect the fractal interpolation results. 4.3.1 Vertical Scale Factor According to the requirements principles of fractal interpolation on the vertical scale factor, different di values is selected in the condition: 0 ≤| d i |≤ 1 , In order to analyze directly the vertical scale factor on the effect of the interpolation, this method of direct value is used, which are taken di = 0.05, di ∈ 0 0. 2 , d i =0.2, d i ∈ 0 1 the measured data (Figure 1 data1) Figure 20 points sampling interval) are fractal interpolated, interpolation process selects the same number of iterations (interpolation results Figure omitted). Root mean square method is used to analyze fractal characteristics of the interpolated curve of shown in Figure 5, the characterization parameter of fractal interpolation curve calculation is shown in table 2 below.
(, )
(,)
Fig. 5. Fractal plots of interpolation curves with different vertical scale factor Table 2. Comparison of parameters with different di
parameters root mean square fractal dimension
∈
∈
Measured data 1.6606
d i = 0.05
d i (0,0.2)
d i = 0.2
di (0,1)
1.5931
1.6299
1.6453
1.8443
1.6298
1.4081
1.6113
1.6093
1.5698
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From Figure 5, it can be found that the simulated curves obtained by interpolation in the first scale have good fractal characteristics, and the slopes are close, but with the selected vertical scale factor increasing, the scaling law curve in the double logarithmic coordinates of the intercept increases, therefore, the physical meaning of the root mean square method calculating fractal dimension can explain the vertical scale factor is directly related to the absolute measure of the value of road roughness size, which is the important factor to effect fractal interpolation. In the measured surface roughness simulation of fractal interpolation, it is needed to consider the vertical scale factor. From comparison characterization parameters between measured data and simulated curves under different vertical scale factor in Table 2, it shows that when di =0.2, di ∈ 0 0. 2 , root mean square deviation by the interpolation curve is
(, )
close to that by the measured curve, which is consistent with the Analysis of Fractal Interpolation scaling law curve in double logarithmic coordinates log S (τ ) and log τ in the size of the intercept in Figure 5 and the vertical scale factor values greater, RMS deviation of surface roughness greater and the road more rough. the fractal dimension of the first scale range calculated by RMS is also small difference with the measured data, therefore, when the measured surface roughness is simulated by the fractal interpolation, the vertical scale factor in its allowable range can be neither too large nor too small. 4.3.2 Sampling Interval To be Convenient for the comprehensive analysis, measured road roughness in Figure 1 a) is still as the interpolation object. Sampled low-resolution data on road roughness are based on interval 10, 20, 50 points, Resolution R were: R = 1.6m, R = 3.2m, R = 8m, then take the respective analytical method to calculate the value of the vertical scale factor and simulate discrete data points based on these low-resolution data by fractal interpolation, the result of fractal interpolation simulation of the road roughness is shown in Figure 6. Fractal plots of interpolation curves with different R were shown in figure 7. From the figure 7, we can see that the scaling law of the fractal interpolation curve is greater with the high-resolution than with the low-resolution. The meticulous structures of the simulated curve will reduction, when the resolution is too low according the figure 6. Theoretically the sampling interval is smaller is better. In fact, the sampling interval obtains is too small, does not have affects too greatly to increases the scaleless range and the computation fractal dimension value, because of the gathering system's precision or the resolution limit. According to the fractal interpolation theory, so long as the sampling interval in the non-scale sector, the good simulation effect can be obtained with the reasonable influence parameter. But because errors of measure, the vertical scale factor counting and the limit of times of the iterative, the sampling interval is smaller than the one third of scaleless range.
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a)
b)
c) Fig. 6. Effects of resolution of original data to interpolation result. a) R = 1.6m; b) R = 3.2m; c) R = 8m
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Fig. 7. Fractal plots of interpolation curves with different R
4.3.3 The Sampling Length and Number of Iterations Because the curve interpolated in too long curve segment does not have the same as fractal law of the actual road roughness, when the sample length of the original data curve is too large, piecewise interpolation should be needed, each should be less than the length of the largest scale of a fractal rough surface characteristic. According to the definition of fractal interpolation, with the number of iterations increasing, the number of interpolation points is increased to M times every time (M is the number of interpolation points) which is based on the rules of affine transformation. With the increase of the number of iterations, when the interpolation points are enough, the graph of the attractors of iterated function systems is established by the intensive interpolation points. Therefore, when the selected couples of original data interpolation points are less, which the sampling interval is large, it should increase the number of the iteration to generate more points so as to make a interpolation graph structure more precise. However, when the number of iterations increases, the computation also increases and the run time is too long. So when the calculation process, the sample length, sampling interval and vertical scale factor are confirmed, to adjust appropriately the number of iterations to get good simulation results is to avoid difficulties in the cost of computation taken place by the infinite number of iterations.
5 Conclusion Fractal interpolation, which is based on affine transformation iteration function system, can fully reflect the self-similarity structure. Based on vertical elevation discrete data of road surface roughness, continuous simulation curves are produced through fractal interpolation simulation, and these curves not only retain the information of original discrete points but also characterized more detailed information on road
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roughness between the discrete points, so instrumentations’ resolution of road roughness could been reduced. From the preparation of characterizations of fractal interpolation curve and the measured road roughness curve, we can see that the application of piecewise fractal function was feasible in self-similarity simulation of the measured road surface with low resolution. The accuracy of the road fractal interpolation is mainly decided by the computation of the vertical scale factor. At the same time, the iterative number of times and the primary data sampling interval (i.e. resolution) also affects the effect of road fractal interpolation.
References 1. Barnsley, M.: Fractals everywere, pp. 207–233. Academic Press, New York (1988) 2. Stamps, A.E.: Fractals, skylines, nature and beauty. Landscape and Urban Planning 60, 163–184 (2002) 3. Sha, Z.: A class of functional equation and fractal interpolation function. Appl. Math. – JCU 14B, 90–98 (1999) 4. Mazel, D.S., Hayes, M.H.: Using iterated function systems to model discrete sequences. IEEE Transactions on Signal Processing 40(7), 1724–1734 (1992) 5. Xie, H., Sun, H., Ju, Y., Feng, Z.: Study on Generation of Rock Fracture Surface by Using Fractal Interpolation. Int. J. of Solids & Structures 38, 5765–5787 (2001) 6. Ruan, H., Sha, Z., Su, W.: Parameter identification problem of the fractal interpolation functions. Numerical MathmaticsA. Journal of Chinese Universities 12(2), 205–213 (2003)
Stress Analysis Near the Welding Interface Edges of a QFP Structure under Thermal Loading Zhigang Huang, Xuecheng Ping, and Pingan Liu School of Mechatronics Engineering, East China Jiaotong University, Nanchang, Jiangxi Province, P.R. China, 330013 [email protected]
Abstract. The purpose of this paper was to investigate the reason why the interface delaminations occurred in the QFP structure. The stress concentration was the key factor responsible for the microcrack occurrence. In order to figure out which factors affect the stress distribution, the material’s attributes and the structure’s dimension were considered. The finite element program ABAQUS6.9 together with the analytical solutions of singular stress fields was used to calculate the stresses near the interface edges. In conclusion, it appeared that strong mismatches of the thermal expansion coefficients and material elastic constants of the chip and PCB would lead to serious singular stresses at the interface edges. Stress intensity factor K and stress singularity order λ were given, based on which failure criterions could be established to predict the potential interface delamination. It is suggested that the good design of packaging structure depends on proper material selection and dimension determination. Keywords: Electronic packaging, QFP structure, Interfacial thermal stresses, Stress concentration.
1 Introduction Nowadays, quad flat packages(QFPs) are widely used in electronics engineering. A QFP structure often consists of metal pins, solder and PCBs. This kind of structure has two common features such as interfaces and corners. The solder layer plays an important role in the mechanical and electric connections. The require-ments of highdensity,cost-effective performance for package have resulted in very high IO count in smaller dimensions in the chip design(A.Q. Xu et al.2000)[1]. Due to the mismatch of thermal and mechanical properties in the dissimilar material structures as well as the change in working or environment temperature, high stress singularity will appear at the interface edges. Since the solder interlayers tend to be weak mechanically, in which microcracking or delamination are more easy to occur, the strength and service life of the whole structure will be directly reduced (Yi lan Kang 1996)[2]. Therefore, the awareness of the stress state near the interface edges is very essential to the strength evaluation and life prediction. Many researchers have studied these problems and have brought some methods to relax singular stresses at the interface edges. Failure criterions have also been discussed by some scientists. The stress singularity problems at the free edges of bonded D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 306–313, 2011. © IFIP International Federation for Information Processing 2011
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dissimilar materials were analyzed previously(Shuir 1989 and Munz and Yang 1992)[3,4]. The stress singularity problems of the edge of bonded bimaterial beams were discussed by some scholars (Kang et al. 1995)[5]. The stress singularities in an anisotropic wedge was analyzed (Chue et al.2001)[6]. The failure models and strength criterions were studied experimentally (Basaran et al. 2005 and Park et al. 2002)[7,8]. Effects of geometrical structure and dimension on thermal stress distribution were analyzed based on the finite element method (Jiang et al.2006 and Cho et al. 2009)[9,10]. The failure usually initiates at the singular stress point, and the knowledge of interfacial fracture mechanics is important to understand the failure mechanisms and to achieve better structure design. Although some jobs have been done by some scholars in this area (Seiji Ioka,and Keiji Masuda, et al.1999)[13], there were relatively few papers to discuss the singular thermal stresses near the interface edges. It should be pointed out that, 1) the thermal stress is singular near the sharp corner of the electronic packages, it is difficult to calculate the singular stress fields by the conventional finite element method(J.M. Hu 1995)[11]; 2) the effects of solder thicknesses for a pin/PCB joint on the singular thermal stresses were not systematically studied. In this paper, the above two problems are going to be researched.
2 Theoretical Background If two materials with different elastic properties are bonded together, stress singularities often occur at free edges of the interface under mechanical or thermal loading. A general configuration of a joint between two rectangular plates is shown in Fig.1. The stress states near the free edge of the interface (point o) is given by the following equation: σ ij (r , θ ) =
K f ij (θ ) + σ ij 0 (θ ). (r / L ) λ
(1)
where r and θ are the polar coordinates of the specified point o and L is a characteristic length of the configuration. λ is the stress singularity order, f ij (θ ) is the angular variations of stresses, and K is the stress intensity factor. λ, f ij (θ ) and K are all dependent on the material constants and the wedge angles or shapes. σ ij 0 (θ ) is the
Fig. 1. A configuration of the interface edges
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constant stress term under the thermal loading. In order to determine its value, we can use the following formulas(Suga and Lancu 1989): σ (2) σ θ 0 = 0 (1 + cos 2θ ). 2
if with
θ = 0 , σ θ 0 = σ 0 .Where σ 0
is defined by:
σ 0 = Δα ∗ ΔE ∗ ΔT .
(3)
Δα = α1 (1 + v1 ) − α 2 (1 + v2 ).
(4)
⎡ 1 1 ⎤ ΔE = ⎢ ∗ − ∗ ⎥ E2 ⎦ ⎣ E1 E∗ =
−1
E . v(1 + v )
(5) (6)
where, ΔT =T-T0 is the temperature difference, T is the working temperature, and T0 is the initial temperature. E is the Young modulus, and E ∗ is the effective modulus.α is the thermal expansion coefficient.
Fig. 2. Section of the Package Components
3 Analysis of the QFP Welded Joints The welded pin joint in a QFP structure is shown in Fig.2. The upper layer is the pin, the bottom layer is the PCB, and the medium layer is the solder. The detailed dimension of these components is shown in Fig.2. The material properties for the pin, PCB and solder are listed in Table.1.The finite element model of the welded joint is given in Fig.3. In order to guarantee the calculation accuracy, the meshes near the interface edges are refined systematically. During the compu-tation and analysis, the finite element model must be based on the following assumptions(Jamil Wakil,and Paul S Ho 2007)[12]:
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1) Temperature for the thermal analysis dropped from 183°C to an ambient environmental temperature of 20°C, since the QFP package is in a stress free state over 183°C-the melting point temperature of the solder. Simplifications are made to facilitate prediction of junction temperatures and therm-mechanical stresses. 2) Thermal cycling was not considered, and the temperature dropped from 183°C to 20°C in 90 minutes. 3) The temperature condition was applied simul-taneously to the entire package. 4) A horizontal line on the bottom substrate surface was fixed along the Y-direction to constrain free body motion. The upper horizontal line of the pin was constrained using the same pattern. These were the boundary conditions of the analysis model. 5) All component interfaces were assumed to adhere perfectly and the material properties do not change with the temperature.
Fig. 3. Finite element model of the QFP Table 1. Thermodynamics parameters of the materials in the model Material Cu Pb40Sn60 FR4
E (Mpa) 120658 34590 22000
ν 0.345 0.38 0.28
ρ 8900 8400 1800
α 17e-5 21e-5 18e-5
c 385 176 930
Fig. 4. Distribution of the peeling stress along the interface
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4 Result and Discussion Fig.4 presented the peeling stress distribution along the interface of pin and PCB resulted from the cooling process. It was obvious that strong stress singularities existed at the point o, and the interface delamination may initiate from here. Once the peeling stress σ y and the constant stress term σ 0 are obtained, according to Eq. (1), the λ and K can be obtained from the following plots:
(
)
lg σθ FE − σ 0 = lg K − λ lg(r / L) .
where σ θ
FE
(7)
is the stress value calculated by the finite element method. Fig.5 shows an
example of these plots. It was found that the slope of the straight line through the data points in the range -4
Fig. 5. Relation between lg(σy-σ0) and lg(r/L)
Fig. 6. λ’s variation against different α2
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Fig. 7. K1/ΔT varied against different α2
Fig.8 showed the effect of changing α2 on the K1/σ0. The result was that larger α2 leads to larger K1/σ0. Fig.9 showed the effect of the poisson’s ratio on the term K1/ΔT including the stress intensity factor. In order to study the effect of the mismatch of thermal and mechanical properties of the bonded materials on the stress distribution, the FE plot of σy/ΔT versus k(=
E 1* − E 2 * ∗
E1 + E 2
∗
) was given in Fig.10. It can be
seen that σy/ΔT decreases with the decreasing of k. In some cases (e.g. k<0.2), the compressive stresses will appear.
Fig. 8. -K1/σ0 varied against different α2
Fig. 9. -K1/ΔT varied against different ν2
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Fig. 10. σY/ΔT varied against R/L with different K
In Fig.11, the effect of thickness of the solder layer on the peeling stress σy/ΔT was considered. In the analysis, the thermal and mechanical properties of the materials were constants. It was easy to see that the peeling stress σy/ΔT will increase with the increasing of the solder layer’s thickness. Therefore, thinner solder layer is recommended on the premise of enough bonding strength.
Fig. 11. σy/ΔT varied against different solder thickness
5 Conclusions The thermal stress distribution at the interface between the chip and PCB was affected by the material’s properties and the structure’s dimension. The peeling stress’s distribution is also dependent on the solder layer’s thickness. The effects of α2 on K1 and λ are different, and the stress intensity factor K1 is very important to predict the interface failure occurrence. The peeling stresses are directly proportional to the r-λ and the stress values near the free edges (when r approaches to zero) are very rigorous theoretically. It is in accordance with the results of the finite element analysis. The analysis of thermal stresses along the interface is very important for guiding the good design of packaging structures. Acknowledgements. The authors acknowledge the support of National Natural Science Foundation of China through grant No.10362002 and No.10662004, the Jiangxi
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Provincial Natural Science Foundation of China through grant No. 2007GZW0862 and the Scientific Research Project of Jiangxi Provincial Department of Education grant NO. GJJ10444.
References 1. Xu, A.Q., Nied, H.F.: Finite Element Analysis of Stress Singularities in Attached Flip Chip Packages. ASME. Journal of Electronic Packaging, 301–305 (2000) 2. Kang, Y.: The thermal stress analysis of the interfacial edge in dissimilar structure and the effects of geometric shape. Transactions of tianjin university 2(2) (1996) 3. Suhir, E.: Thermally induced interfacial stresses in elongated bimaterial plates. Appl. Mech. Rev. 42(11), s253 (1989) 4. Munz, D., Yang, Y.Y.: Stress singularities at the interface in bonded dissimilar materials under mechanical and thermal loading. Journal of Applied Mechanics 59(4), 857–861 (1992) 5. Kang, Y.L., Learmann, K.H., Jia, Y.Q.: Experimental analysis for bonded bimaterial beam under bending load. Measurement 15(2), 85–90 (1995) 6. Chue, C.-h., Liu, C.-I.: A general solution on stress singularities in an anisotropic wedge. International Journal of Solids and Structures 38, 6889–6906 (2001) 7. Basaran, C., Ye, H.: Failure Modes of Flip Chip Solder Joints Under High Electric Current Density. Journal of Electronic Packaging 127, 157–163 (2005) 8. Park, J.-W., Mendez, P.F., Eagar, T.W.: Strain energy distribution in ceramic-to-metal joints. Acta Materialia 50, 883–899 (2002) 9. Jiang, C-s, Xie, K-j.: Interfacial Thermal Stress Analysis in Packaging. Electronic & Packaging (2006) 10. Cho, S., Choi, J.: Study on the Behavior Characteristics of Solder Balls for FCBGA Package. Met. Mater. Int. 15(2), 299–305 (2009) 11. Hu, J.M.: Interfacial stress singularity analysis: A case study for plastic encapsulated IC packages. Application of Fracture Mechanics in Electronic Packaging and Materials, AS/VIE EEP-11/ MD-64, 13–21 (1995) 12. Wakil, J., Ho, P.S.: Effect of non-uniform temperature on thermal modeling and strain distribution in Interlayer. International Journal of Solids and Structures 44, 6232–6238 (2007) 13. Ioka, S., Masuda, K., et al.: Singular stress field near the edge of interface of bonded dissimilar materials with an electronic packaging. In: Electronic Components and Technology Conference, pp. 330–337 (1999)
Study of Intelligent Diagnosis System for Mechanism Wear Fault Based on Fuzzy-Neural Networks Sanmao Xie* School of Mechanical Engineering, East China Jiaotong university, Nanchang 330013, China Tel.: +86-791-7046135; Fax: +86-791-7046122 [email protected]
Abstract. According to fuzziness and complexity of mechanism wear fault, a kind of intelligent diagnosis system for mechanism wear fault based on fuzzyneural network is put forward. The structure and learning method of fuzzy-neural network are introduced. This paper analysises how to create the characteristic vector of wear particles and standard wear particles spectrum by combine the characteristics of mechanism wear fault, and the fuzzy-neural network of mechanism wear fault intelligent diagnosis is built. Mechanism wear faults can be diagnosed to apply the fuzzy-neural network and fault causes are determined. This system is developed by applying MATLAB software and the GUI functione of MATLAB for the simplicity and intuition of diagnosis. Keywords: wear, fault diagnosis, fuzzy-neural networks, study.
1 Introduction In mechanical faults, the wear faults occupy a large proportion of faults. For this type of fault diagnosis, common method is to use the oil sample analysis. However, oil sample analysis often can’nt obtained complete wear particles information, we required abundant experience to identify wear particles and wear. Therefore, the study on computer recognition of wear particle, that is intelligent diagnosis, has important significance. Common identification theory and diagnostic techniques of intelligent diagnosis have gray theory, fuzzy diagnosis, neural network diagnostic technology and so on[1]. Fuzzy-neural network is combined with fuzzy theory and neural networks. It not only can describe the problem with fuzzy concepts, but also has strong learning ability and processing capabilities of data. According to fuzziness and complexity of mechanism wear fault, this paper analysises how to create the characteristic vector of wear particles and standard wear particles spectrum by combine the characteristics of mechanism wear fault, a fuzzy-neural network is introduced and an intelligent particale recognition system is attained.
2 Structure of Fuzzy-Neural Network In general, the combination of fuzzy systems and neural networks has four modes: loose combination, parallel combination, Series combination and learning combination. *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 314–320, 2011. © IFIP International Federation for Information Processing 2011
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The Series combination is simple and easy to be achieved, so in this paper, Series combination is used. According to fuzzy logic and neural network features, fuzzy-neural network is built as Figure1. It is composed of three modules[3]: (1) Input fuzzy module: to complete the transformation form fault symptoms to input vector. (2) ANN inference module: to apply BP neural network to complete the reasoning diagnosis process. (3) Output clarity module: to complete the process from the output of BP neural network to the diagnosis result. In fuzzy-neural network ,first, the fault symptoms are quantified based on fuzzy theory, the input vector is attained, second, output vector is attained by the learning and reasoning of BP neural network, finally the results of fault diagnosis is attained by comparing output datda with each other.
Fig. 1. Structure chart of fuzzy-neural network
3 Establishment of Standard Particale Spectrum The priori knowledge of typical wear particls must be determined to recognize wear particles and classify wear, that is to establish standard particle spectrum. According to research, wear usually are divided into five basic types: normality, fatigue, abrasive, cutting and sliding. Relating to wear, wear particles are classified into ‘normality’,‘expanse slice’,‘stick’,‘sphere’,‘cutting’and ‘severe sliding’. Wear particle of normality is ‘normality’. Wear particle of fatigue is‘expanse slice’or‘stick’. Wear particle of abrasive is ‘sphere’. Wear particles of cutting is ‘cutting’. Wear particle of sliding is ‘severe sliding’.This six kinds of particles can be described with the feature vector of five parameters such as outline shape, edge detail, surface texture, size, ratio of length to thickness[2]. As follows:
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K1—outline shape,K2—edge details, K3—surface texture,K4—size,K5—ratio of long-thickness Based on the reference [1], [2] and linear principles, the following quantization values of particle features are obtained by combination of the particle characteristics and the typical morphology[1][2]: outline shape: K11- spherical shape(1.0), K12– flake shape (0.8), K13– circular shape (0.6), K14- elongated shape (0.4). edge details: K21- smooth edge(1.0), K22- straight edge (0.8), K23- irregular edge(0.6) surface texture: K31- smooth surface (1.0) , K32- rough surface (0.8), K33- striated surface (0.6), K34 – holed surface (0.4), K35- pitted surface (0.2) size: K41<15μm (1.0), K42: 15 ~ 25μm (0.8), K43:25 ~ 100μm (0.6), K44 > 100μm (0.4) ratio of length to thickness: K51<5:1 (1.0), K52:5:1 ~ 10:1 (0.8), K53> 10:1 (0.6) The data in brackets express the quantization values of particle features. According to expert experience and knowledge, the following typical particles feature vectors are obtained: ‘normality’particle feature vector: X1= (0.8,1.0,1.0,1.0,0.8) ‘expanse slice ’particle feature vector : X2= (0.8,0.6,0.4,0.6,0.6) ‘stick’particle feature vector : X3= (0.6,0.6,0.8,0.6,1.0) ‘sphere’particle feature vector: X4= (1.0,1.0,1.0,0.8,1.0) ‘cutting’particle feature vector: X5= (0.6,0.6,0.8,0.6,0.6) ‘severe sliding’particle feature vector: X6= (0.4,0.6,0.6,0.4,1.0) Thus the quantified standard particle spectrum is shown in table 1: Table 1. Standard particle spectrum
Xi X1 X2 X3 X4 X5 X6
K1 0.8 0.8 0.6 1.0 0.6 0.4
K2 1.0 0.6 0.6 1.0 0.6 0.6
Km K3 1.0 0.4 0.8 1.0 0.8 0.6
K4 1.0 0.6 0.6 0.8 0.6 0.4
K5 0.8 0.6 1.0 1.0 0.6 1.0
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4 Procedure of Wear Fault Diagnosis Based on Fuzzy-Neural Network Procedure of wear fault diagnosis based on fuzzy-neural network is shown in figure 2. Wear particle characteristic information are obtained from the oil sample analysis. After fuzzy processing, the feature vector of particles is provided to the diagnosis system by man-machine interaction. The diagnosis result of wear fault is shown by learning and reasoning of neural network.
Fuzzy processing of particle characteristics
Input feature vector of particle Learning and Reasoning
Diagnosis Result
Quantitative standard particle spectrum Fig. 2. Flow chart of wear fault diagnosis
5 Design of ANN Inference Module 5.1 Structure of ANN Inference Module In this module, a three-layer BP neural network with input-layer, hidden-layer and output-layer is used and hybrid algorithm of ‘BP-random’ is adopted to train the network. Parameters of BP neural network are selected as following: (1) the number of input-layer node: As the five particle morphology parameters are as input after fuzzy, so 5 nodes are selected in input-layer; (2) the number of outputlayer node: Since there are six kinds of wear particle, so 6 nodes are selected in output-layer; (3) the number of hidden-layer node: According to the reference [1], the following formula can be used to determine the number of hidden-layer node:
l = n + m + a , n is the number of input-layer node, m is the number of outputlayer node, α is a constant between 1 to 10. As a result, 10 nodes are selected in hidden-layer; (4) extraction of network training sample: According to the expert experience and knowledge, features spectrum of the typical wear particles has been shown in Table 1, so the features spectrum is used as the input training sample P of neural network. Table 2 shows the target output training samples T of the neural network, its output value is in the range [0,1], the greater the value, the greater the likelihood of that type of fault.
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Output node Particles type ‘normality’ ‘expanse slice’ ‘stick’ ‘sphere’ ‘cutting’ ‘severe sliding’
Node 1 1 0 0 0 0 0
Node 2 0 1 0 0 0 0
Node 3 0 0 1 0 0 0
Node 4 0 0 0 1 0 0
Node 5 0 0 0 0 1 0
Node 6 0 0 0 0 0 1
5.2 Implementation of BP Neural Network BP neural network's basic idea is that characterized vector of training sample is as input of neural network, an output is get after the forward propagation calculation of neural network, and then the output is compared with a expected sample output, if there is deviation, the deviation is propagated back from the output layer, the network connection weights and thresholds are adjusted, the network's desired output is consistent to the output of the sample[4]. MATLAB software has stronge function of mathematical calculation, image processing and computer simulation and has a very high programming efficiency. It is more important that MATLAB concentrated the wisdom of experts and scholars in many fields and successfully expanded the toolbox of more than 30 fields, in which neural network toolbox is based on the theory of neural network. Utility functions of typical neural network is constructed in MATLAB. It provides a powerful and convenience tool for the application of the BP neural network[5][6].Therefore, this system is developed by applying MATLAB software and the GUI functione of MATLAB for the simplicity and intuition of diagnosis. BP neural network is created as follows: net = newff (minmax (P), [5 10 6], ('pureline''logsig' 'logsig'), 'trainlm') Choose η = 0.2, α = 0.85, and the system error is 0.001, the corresponding network parameters: net.trainParam.mc = 0.85; net.trainParam.lr = 0.2; net.trainParam.goal = 0.001; The neural network is initialized and trained according to the samples of Table 1 and Table 2. As following: net = train (net, P, T).
6 The Main Function of This Intelligent Diagnosis System As MATLAB software has a powerful function of mathematical calculation and friendship GUI visual interface, so this system is developed by applying MATLAB software, the functions of system include:
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1) the system description; 2) neural network training; 3) wear particle recognition and wear fault diagnosis; 4) the help of system. Testing example of diagnostic system: According to the analysis of a particular ferrography, we obtained the characteristics information of wear particle tested. Feature vector X0 was attained through fuzzy processing, as follows: X0= [0.6,1.0,0.8,0.6,0.8] In fact, these data is the wear particle membership of characteristics. Feature vector X0 was as the input of diagnosis system, the network output value is: Y = [0.0025 0.0061 0.0016 0.9332 0.0064 0.0086] Obviously, the fourth is largest data of output nodes, the particle is ‘sphere’, the corresponding wear is abrasive wear. The diagnosis result is shown as Figure 3.
Fig. 3. Diagnosis result of wear fault
7 Conclusion In this paper, mechanical wear faults were diagnosed effectively after obtaining characteristics information of wear particles and processing them with fuzzy theory. The effective combination of fuzzy theory and neural networks can handle ambiguous and even erroneous information.
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References [1] Yu, H., Cheng, C.z., Zhang, s., Zhou, J.n.: Intelligent Diagnosis Based on Neural Networks. Metallurgy industry publishing house, Beijing (2002) [2] Huang, A., Chen, Z.n., Zhu, J.m.: The Application of Artificial Neural Networks to Wear Debris Recognition in Ferrography Technology. Drive System Technique (1), 42–46 (1997) [3] Li, G.-y., Yang, Q.-f.: FNN-based Intelligent Fault Diagnosis System for Vehicle Engine. Journal of System Simulation 19(5), 1033–1037 (2007) [4] Li, G., Zhang, Y.: Machinery fault diagnosis. Chemistry industry publishing house, Beijing (1999) [5] Zheng, A., Chao, y., Zhao, Y.: MATLAB Practical course. Electronic industry publishing house, Beijing (2004) [6] Cong, S.: Neural Network Theory and Applications Based on MATLAB Toolbox. China Science and Technology University publishing house, Hefei (1998)
Study on Autonomous Path Planning by Mobile Robot for Road Nondestructive Testing Based on GPS Lunhui Xu1, Fan Ye2, and Yanguo Huang1 1 Faculty of Mechanical and Electronic Engineering, Jiangxi University of Science and Technology, Ganzhou, P. R. China, 341000 2 South China University of Technology of Traffic Collage, Guangzhou, P. R. China, 510006 [email protected], [email protected], [email protected]
Abstract. This paper analyses the statements of video imaging, CT, infrared thermography and radiography applied in the road nondestructive testing, and design a path planning mobile robot with GPS positioning which can remarkably increase the efficient of road nondestructive testing. Besides, appropriate algorithm for nondestructive testing on the road autonomous mobile robot path planning is given. This method is simplicity, versatility, and efficiency. The mobile robot are selected for example and the simulation results represent the effectiveness of this method. Keywords: road nondestructive testing, GPS, path planning, mobile robot.
1 Introduction Because of the natural factor and long-term used, roads may be damaged. The damaged road is harmful to the safety of vehicles, so the regular road testing is necessary. While testing the road’s structure, the destructive testing may descend the traffic capacity and waste a lot of money and time. So, to meet the requirements of road development and ensure road traffic safety, nondestructive testing (NDT) is becoming more and more important. But the traditional method of road nondestructive testing is manual operation, which can only carry out a limited number of testing, and may not achieve long-term monitoring. In addition, traffic flow on major highways, testing personnel may be braved danger. Therefore, making the manual testing developed to automated testing technology, and low-speed, low accuracy developed to high-speed, high precision is critical important. So, a fast, accurate and nondestructive road testing method is needed urgently. The constant improvement of science and technology promotes the growth of mobile robot for road nondestructive testing. Instead of human beings, mobile robot for road nondestructive testing can suffer a large number of works with strong intensity, long time, high repeatability and terrible environment. These objective requirements propel the widely development in the study of mobile robot. Path planning is one of the important core problem and technique in the research area of mobile robot that not only develops fast but also contributes a lot [1]. Path planning by mobile robot refers that it can search for the best (or second-best) and reasonable moving strategy from the initial status (including position and angle) to the D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 321–332, 2011. © IFIP International Federation for Information Processing 2011
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final status by following the planed path. It is the foundation for the mobile robot to execute different kinds of tasks. In this paper, appropriate algorithm for nondestructive testing on the road autonomous mobile robot path planning is given .The feasibility of the scheme and algorithm proposed in this paper was verified by the experimental prototype test data.
2 Current Statements of Road NDT Currently, the major testing methods of nondestructive testing methods are including video imaging, CT, infrared thermography and radiography. The introductions of all of the methods are as follows: 2.1 Video Imaging Video imaging systems have become versatile data-gathering tools because of their high spatial resolution, near real-time image availability and computer compatibility. Current video imaging is widely used for non- Destructive testing. There are a lot of digital video imaging systems which can be used for the pavement broken testing such as PAVUE and WiseCrax [2]. These systems are widely used for Nondestructive testing; the steps of using these systems are as flows: 1. 2. 3.
Get the image of the pavement, and then input this digital images into computer; Change the consecutive images into still images, use the image processing technology to analyze and classify the still images. Evaluate the road damage level and parameter such as crack breadth, length and square and so on. Meanwhile, according to the GPS, passion the damage section.
2.2 Computed Tomography (CT) In highway construction, to ensure the quality of engineering, relative mass detection is needed in a wide range including tamping foundation, rolling sub grade and paving pavement. The traditional detection is to on-site observe the roads and sample from drilling for the laboratory analysis, so that the control parameter of engineering quality, such as thickness, depth, degree of compaction and strength, can be obtained. However, this routine method has some limitation. First, it can be omitted easily although the measured points are selected randomly so that they should be representative to some extent. Second, the problems about the damage of the pavement, such as crack and sag, can be easily found, while the inner problems of the roads are difficult to find out. Therefore, some nondestructive, fast and direct test equipment and technique that can show the inner status of the roads is necessary for the improvement of highway construction and maintenance level. CT was invented in 1972. In the early stage it was only applied in X-ray, then the application was widely extended, including emission computed tomography (ECT), ultrasound computed tomography, magnetic resonance imaging (MRI) and so on.
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This technique was at first applied in the field of biomedicine. The basic method of CT is image reconstruction, which refers to the reconstruction of the cross-section image obtained from projections of measured objects by the computer. Application of CT in road quality testing is like perspective diagnosis of the roads, which can help us to detect the diseases promptly and have a direct view. This technique has been used in the pavement detection by ground penetrating radar. The road radar, which is based on the use of transient electromagnetic waves, emits high-frequency spike pulse electromagnetic waves to the underground by wide time-domain transmitting antenna. When waves meet different interfaces of dielectric during the underground transmission, reflection happens. Then it is received by receiving antenna and handled by the computer, which can analyze the obtained digital signal, so that we can get three dimensional computed tomography imaging for the underground target. Accordingly, we are able to clearly observe the cavity of sub grade, thickness and deformation of the pavement structural layer, even the water under the surface. 2.3 Infrared Thermography (IRT) Infrared thermography (IRT) has established as a fast and reliable tool in many areas of non destructive testing. In recent years, IRT has emerged as a widely used method for road nondestructive testing. The IRT is bound up with thermal conductivity. With the influence of heat source, objects’ surface will have some thermal spread. The difference of the thermal distribution can be used to detect the material difference under the objects’ surface. IRT can image and orient horizontal plane and holes under the road efficiently. Compare with other NDT methods, IRT has following advantages: 1. 2.
3. 4. 5.
Fast inspection rate, which can up to a few m2 at a time; No contact. No couplant needed although in some cases a black painting step is required to perform the inspection so that strictly speaking, a contact is thus present in this case; Security of personnel. Since there is no harmful radiation involved, however high power external stimulation-such as powerful flashes-requires a shroud; Results are relatively easy to interpret; Unique inspection tool for some inspection tasks.
But on the other hand, there are some difficulties specific to IR thermography as follows: 1. 2. 3. 4. 5. 6.
Difficulty in obtaining a quick, uniform and highly energetic thermal stimulation over a large surface; Effects of thermal losses (convective, radiative) which induce spurious contrasts affecting the reliability of the interpretation; Cost of the equipment; Capability of detecting only defects resulting in a measurable change of the thermal properties; Ability to inspect a limited thickness of material under the surface; Emissivity problems.
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2.4 Radiography Radiography is a method that makes use of strong radiation, such as X-ray, to detect the inner situation of the object. Now this technique has been applied in the nondestructive test of the concrete. According to the sensitive photograph obtained from the steel bar and its defect inside the concrete, quantitative assessment is available by using the digital image analytical technique. Besides, other imaging technique, such as ultrasonic imaging, interference imaging, is widely used in the test of road material. The application of these technique remarkably increases the quality of the road nondestructive testing, thus has an important role in enhancement of the development of our highway and transportation.
3 The System and Mechanical Structure of the Mobile Robot 3.1 The System in Introduction The system structure of autonomous path planning mobile robot for road NDT shows in the Figure 1. The whole system using distributed control mode. First of all, used the GPS coordinate acquisition equipments to get the path information, then according to the coordinate information and the initial and final statement of the mobile robot, get robot motion curve function, and use the PC to figure out the kinematic parameter from the motion curve and kinematic model, send the parameter to the lower computer, which use AT89C51 single chip to control the step motors. Meanwhile, the NDT equipments on the robot sent the road information to the lower computer. After finish the whole route, the robot sent the road testing data back to the PC.
Fig. 1. The system structure of autonomous path planning mobile robot for road NDT
3.2 The Structure of the Mobile Robot The research object of this paper is based on the mobile robot which is researched and designed by SCUT. The mobile robot use differential drive method, there are three
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wheels on the robot, two wheels are controlled by two step motors at front of the robot, which are as the drive wheels, the other rear wheel using flexible wheel at back to support the body of the robot. The moving direction is controlled by speed differential of the front two wheels.
4 Fitting for the Path Moving Function Here, we use the regression equation to fit the moving function of the planed path. Regression equation is a statistical technique which can be used to predict the value of one variable using the value of one or a quantitative variable. According to the relationship between the two variables, regression equation can be divided into linear and nonlinear. According to the number of the variable, regression equation can be divided into unary and multiple. 4.1 Linear Multiple Regression Equation Supposing
y is a random scalar, which has linear relationship with independent va-
x1 , x2 ..., xn , and according to the value of n samples ( xi1, xi 2 ,...xin ; yi ) ˆ ˆ ˆ ˆ (i = 1, 2,...n ) , we can get the least squares estimation b0 , b1 , b2 ,...bm . A multiple regres-
riables
sion equation for predicting yˆ can be expressed as follows:
yˆ = bˆ0 + bˆ1 x1 + bˆ2 x2 + ... + bˆm xm
(1)
= ∑ ( y j − b0 − b1 x1 j − b2 x2 j − L − bm xmj ) 2
(2)
n
With Q = ∑ ( y j − yˆ j )2 j =1
n
j =1
Where Q is the function of b0 , b1 , b2 ,…, bm . According to the extreme value theory of multivariable function [7], when Q get the minimum value: n ⎧∂Q 1 1j −b2 x2 j −L−bmxmj ) = 0 ⎪∂b =−2∑(yj −b0 −bx j =1 ⎪ 0 ⎨ n ⎪∂Q =−2 x (y −b −bx −b x −L−b x ) = 0 ∑ ij j 0 1 1j 2 2j m mj ⎪⎩∂bi j =1
( i =1、2、…、 m )
(3)
With above, (1) can be rewritten as: ⎧ nb0 + b1Σxi1 + b2 Σxi 2 + L + bm Σxim = Σyi ⎪ 2 ⎪b0 Σxi1 + b1Σxi1 + L + bm Σxi1 xim = Σx1i yi ⎪ ⎨Σx2 b0 + b1Σxi 2 xi1 + L + bm Σxi 2 xim = Σxi 2 yi ⎪ .......................................... ⎪ ⎪⎩b0 Σxim + b1Σxim x1 + L + bm Σxim2 = Σxim yi
(4)
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From the first equation of (4), we can get the following expression: bˆ0 = y − bˆ1 x1 − bˆ2 x2 − L − bˆm xm
(5)
Substituting (5) into (4), we have ⎡bˆ1 ⎤ l −1 ⎡ 1 y ⎤ ⎢ ⎥ ⎡l11 l12 Ll1m ⎤ ⎢ ⎥ ⎢bˆ2 ⎥ ⎢ ⎥ ⎢ l2 y ⎥ ⎢ ⎥ = ⎢l21 l22 Ll2 m ⎥ ⎢ ⎥ ⎢ M ⎥ ⎢l l Ll ⎥ ⎢ M ⎥ ⎢bˆ ⎥ ⎣ m1 m 2 mm ⎦ ⎢lmy ⎥ ⎣ ⎦ ⎣ m⎦
(6)
Where: 1 ⎧ ⎪luv = ∑ ( xiu − xu )( xiv − xv ) ⎪ m i, u, v = [1, m] ⎨ 1 ⎪l = ( x − x )( y − y ) iu u i ⎪⎩ uy ∑ m
After this, the value of bˆ0 can be got when substituting bˆ1 , bˆ2 ,...bˆm into equation (5). So the linear multiple regression equation can be got as (1) shows. 4.2 Nonlinear Regression Equation
In statistics, nonlinear regression is a form of regression analysis in which observational data are modeled by a function which is a nonlinear combination of the model parameters and depends on one or more independent variables. The data are fitted by a method of successive approximations. Some nonlinear regression problems, such as hyperbola regression model, logarithmic regression model and polynomial regression model can be moved to a linear domain by a suitable transformation of the model formulation [8]. But others have to deal with nonlinear regression model such as exponential model and S curve model.
5 Kinematic Modeling for the Road NDT Mobile Robot Mobile robot kinematic modeling is the foundation of its motor system control. Accurate kinematic model plays a key role in the motion control system. 5.1 Curve Fitting of Moving Mobile Robot
It can be seen from Figure.2, when robot reached the point n, the track for robot moving from point n to point n+1 can be derived by fitting the robot moving function based on point n to point n + k . In this paper, we takes k=5, and only use 3 order polynomial regression models to fit the curve. So, the form of the moving function is as follow: y (n) = b0 n + b1n x + b2 n x 2 + b3n x 3
(7)
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At this time, we can calculate the mobile control mode according to (7). When the robot reached point n + 1 from point n , the new track for robot moving from point n+1 to point n+2 can be derived by fitting the robot moving function based on point n + 1 to n + k + 1 . The form of the moving function is as follow: y (n + 1) = b0( n +1) + b1( n +1) x + b2( n +1) x 2 + b3( n +1) x3
(8)
Fig. 2. Curve fitting of the mobile robot
Just like formula (7), we can calculate the mobile control mode according to formula (8), and so on. As above done, the mobile robot can move along the track which is planned beforehand by adjusting the robot curve. 5.2 Moving Modeling for the Mobile Robot
Figure.3 shows that the mobile robot’s moving curve is a circle with radius R.
Fig. 3. Mobile robot’s moving curve is a circle with radius R
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Suppose that at the moment n, the robot’s centroid is at the point O, the coordinate of O is ( xn , yn ) , and the angel of the robot and the horizontal plane is ϕ( n ) . In the ideal case, the direction of the moving velocity is the same as the moving curve tangent line. So: dxn sin ϕn − dy ( n) cos ϕ n = 0
(9)
from (9), we can get: tan ϕn =
sin ϕn dy (n) = dxn cos ϕn
(10)
At the moment of n + 1 , the mobile robot moves from O to O’, and the coordinate of O’ is ( xn +1 , yn +1 ) , and the angel between the robot and the horizontal plane is ϕ( n + 1) . As shown in Figure.3, θ is the turning angel of the mobile robot, according to the lane Analytic Geometry [9], we can get:
θ = ϕ n +1 − ϕ n = arctan
dy (n + 1) dy (n) − arctan dxn +1 dxn
(11)
Use the Pythagorean theorem, we can get:
θ
Δx 2 + Δy 2 = (2 R sin ) 2 2
(12)
⎧ Δx 2 + Δy 2 ⎪ θ ≠0 ⎪ R = ⎨ 2sin θ 2 ⎪ ⎪⎩+∞ θ =0
(13)
θ θ ⎧ ⎪⎪ Δx = xn +1 − xn = 2 R sin 2 cos( 2 + ϕ n ) ⎨ ⎪ Δy = y − y = 2 R sin θ sin(θ + ϕ ) n +1 n n ⎪⎩ 2 2
(14)
Then
Where
6 Method of Calculating the Kinematic Parameter for the Mobile Robot Kinematic system is one of the important core problems and technique in the research area of differential drive mobile robot control system, and the moving curve of the robot is decided by the robot moving system. Generally speaking, all the moving tracks of the robot are made up of straight lines and curves. So even if the robot moves in different route, the control method is the
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same. Just like above, the robot’s moving tracks can be control accuracy by controlling the ratio of the two driving wheels well. 6.1 The Kinematic Parameter of the Robot When Straight-Line Moving
As shown in Figure.4, in the case of straight-line moving, ϕ n +1 = ϕ n , θ = 0 , and the speed of the left wheel is the same as the right one. If taking the speed ratio of the left wheel and right wheel as k , then k =1 in this case.
Fig. 4. The robot is in the case of straight-line moving
At this time, the distance of the robot moved is: S=
S1 + S 2 = S1 = S 2 2
In (15), S1 is the distance the left wheel moved, and
(15)
S2 is the right one.
6.2 The Kinematic Parameter of the Robot When Curvilinear Moving
As shown in the Figure.3, in the case of curvilinear moving, when the robot is turning left, ϕ n +1 ≠ ϕ n ,θ ≠ 0 the speed of the left wheel is not the same as the right one. So, at this time, from the meaning of k , we can get: k=
v1 v1 ⋅ t S1 ( R − b)θ b = = = = 1− v2 v2 ⋅ t S2 Rθ R
v1 ——the speed of the left wheel; S1 ——the distance of the left wheel moved v2 ——the speed of the right wheel; S2 ——the distance of the right wheel moved; b ——the distance from the left wheel to the right one.
Where:
(16)
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Use (13) input (16) can get:
k = 1−
2b sin
θ
2 Δx 2 + Δy 2
(17)
Use (11) input (17) can get: 2b sin[arctan k = 1−
dy (n + 1) dy ( n) / 2 − arctan / 2] dxn +1 dxn
(18)
Δx 2 + Δ y 2
When the robot is turning right: θ
k=
2b sin v1 v1 ⋅ t S1 ( R + b)θ b 2 = = = = 1+ = 1+ v2 v2 ⋅ t S2 Rθ R Δx 2 + Δy 2
(19)
Use (11) input (19) can get: 2b sin[arctan k = 1+
dy ( n + 1) dy (n) / 2 − arctan / 2] dxn +1 dxn
(20)
Δx 2 + Δy 2
When the mobile robot is curvilinear moving, the distance of the robot moved is: S=
S1 + S2 ( R − b)θ + ( R + b)θ = = Rθ 2 2
(21)
7 Example In order to prove the accuracy of the model set above, we used the mobile robot and PC to simulate this kinematic model. Fist of all, got the information of the moving path, the sampling of the coordinate information is as shown in Figure.5.
Sampling of the coordinate information 2.50 2.00 1.50
samples
1.00 0.50 0.00 0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000
Fig. 5. Sampling of the coordinate information
Study on Autonomous Path Planning by Mobile Robot
Then
input
the
initial
statement
of
the
mobile
robot
π
( x0 , y0 , ϕ0 ) = (0, 0, 0) , and the final statement is
which
331
is
( xn , yn , ϕ n ) = (2π ,1, ) .we got the 2 distance from the left wheel to the right one is b = 0 .2 9 5 m , the radius of the drive
wheels is r = 0.0375m . First of all, use nonlinear multiple regression equation to fit out the next moving function according to the next 5 points’ coordinates, The least squares estimation parameters bˆ0 , bˆ1 , bˆ2 , bˆ3 , as shown in Tab 1: Table 1. Fitting out the moving function
Function
b0
b1
b2
b3
1 2 3 4 5 6 7 8 9 10 11 12 13
1 0.97 0.83 0.53 0.03 -0.52 -0.83 -0.4 1.34 4.91 10.47 17.63 25.32
1.02 1.15 1.48 2.04 2.75 3.43 3.75 3.35 1.92 -0.71 -4.44 -8.85 -13.2
-0.07 -0.22 -0.47 -0.8 -1.13 -1.4 -1.51 -1.39 -1 -0.36 0.47 1.37 2.2
-0.11 -0.06 0 0.06 0.11 0.15 0.16 0.15 0.11 0.06 0 -0.06 -0.11
After this, use the kinematic model to get the kinematic parameters; the PC simulates picture shows in the Figure.6.
The path of the robot moves 2.50 2.00 1.50 1.00 0.50 0.00 0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
-0.50
Fig. 6. The path of the robot moves
Function Function Function Function Function Function Function Function Function Function Function Function Function
1 2 3 4 5 6 7 8 9 10 11 12 13
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Because of the road friction, there is error exist during the testing. But the error is less than 0.2%. So, the model can be thought accuracy.
8 Conclusion This paper analyses the situation about the methods of video imaging, CT, infrared thermography and radiography applied in the road nondestructive testing. Besides, appropriate algorithm for nondestructive testing on the road autonomous mobile robot path planning is given .The feasibility of the scheme and algorithm proposed in this paper was verified by the experimental prototype test data.
References 1. Shi, P.F., Zhao, Y.G.: A Survey of Environment Modeling in Mobile Robot: Design and Research, China, pp.1–6 (January 2010) (in Chinese) 2. Zhang, J., Sha, A.M., Sun, Z.Y.: The Application of Digital Image Processing to Road Nondestructive Test. Shanxi Science and Technology of Communications, Shanxi, pp. 10– 12 (December 2002) (in Chinese) 3. Cheng, H.D., Miyojin, M.: Automatic pavement distress detection system: Information Sciences, pp. 219–240. Elsevier Science, Amsterdam (1998) (in Chinese) 4. Chang, Y., Ma, S.G., Wang, H.G.: Method of Kinematic Modeling of Wheeled Mobile Robot. Journal of Mechanical Engineering, 30–35 (March 2010) (in Chinese) 5. Kim, D.H., Jun-Hooh: Globally Asymptotically Stable Tracking Control of Mobile Robots. In: The 1998 IEEE International Conference on Control Applications, pp. 305–307 (1998) 6. Addison, D.: Introduction to Robotics Technology. Developer works, USA (2001) 7. Fiorini, P., Shiller, Z.: Time Optimal Trajectory Planning in Kinematic Environments. Journal of Applied Mathematics and Computer Science, USA (1997) 8. Zuang, C.Q., He, C.X.: Statistics Statistical. South China University of Technology Press, Guangzhou (2006) (in Chinese) 9. Zuang, C.Q., Yao, Y.X., Luo, J.H.: Higher Mathematics. South China University of Technology Press, Guangzhou (2007) (in Chinese)
Study on Imitating Grinding of Two-Dimensional Ultrasonic Vibration Turning System Leping Liu*, Wen Zhao, and Yuan Ma Key Laboratory of Ministry of Education for Conveyance and Equipment, East China Jiaotong University, 330013 Nanchang, China [email protected], [email protected], [email protected]
Abstract. According to turning instead of grinding process requirements and traditional working principle of ultrasonic vibration turning, a new idea of imitating grinding of two-dimensional ultrasonic vibration turning is brought firstly, and the mechanism of two-dimensional ultrasonic vibration turning is elaborated. Based on the MATLAB software, grinding trajectory simulation and honing trajectory simulation are carried out. Moreover, the design of ultrasonic transducer and ultrasonic horn is completed. Finally, the required mode shapes and resonance frequency are obtained by using the finite-element method, the results prove that the theoretical analysis is correct. Keywords: Two-dimensional, Ultrasonic vibration, Turning; Grinding, Finite element.
1 Introduction Ultrasonic vibration cutting appears in the early 20th century, because of good processing effect in difficult-to-machine materials and difficult processing procedures of common materials. It has aroused great concern to experts and scholars at home and abroad, and actively has carried out research and development. Currently, it has infiltrated into the automotive, aerospace, defense and other areas of the various processing [1]. The traditional ultrasonic vibration turning can reduce cutting force and cutting temperature. It also can improve the machining accuracy and surface quality. But in traditional ultrasonic vibration turning process, flank will rub and strike processed workpiece surface, when tool and workpiece are in the separated states, which seriously affectes the quality of the machined surface and tool life [2,3]. In order to solve the problem above, a new idea of imitating grinding of two-dimensional ultrasonic vibration turning is brought. This improves the quality of ultrasonic vibration turning and realizes turning instead of grinding.
2 Traditional Ultrasonic Vibration Turning Mechanism The traditional ultrasonic vibration turning is to apply a certain frequency and amplitude of vibration to the tool, which improves the effect of turning [4]. *
Corresponding author. Tel.: 13970086701.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 333–344, 2011. © IFIP International Federation for Information Processing 2011
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Tool’s displacement in the cutting direction:
x = a sin(ωt )
(1)
υυ = aω cos(ωt )
(2)
at = −aω 2 sin(ωt )
(3)
Tool’s vibration speed:
Tool’s vibration acceleration:
In formula (1) and formula (2), a is vibration amplitude for the tool, ω is vibration angular frequency. Workpiece cutting speed is υ . The tool separates from workpiece, when υ < aω . The tool and the workpiece touch, when υ > aω , so repeated cycles. For this reason, tip bears alternate pulling stress and compressive stress with the high-frequency ultrasonic vibration.
3 Two-Dimensional Ultrasonic Vibration Turning Structure and Working Principle Ultrasonic processing system consists of ultrasonic generator, ultrasonic transducer, horn, tools, technology devices and so on. Ultrasonic transducer is the core of the system components. Fig. 1 is a diagram of two-dimensional ultrasonic transducer. shroud of transducer, ceramic stack.
A' shows front
C ' shows back shroud of transducer, and B ' shows piezoelectric
A'
C'
B'
A
B
Fig. 1. The structure of two-dimensional ultrasonic transducer
Piezoelectric ceramic stack is composed of 4 piezoelectric ceramic disks, which is divided into group A and group B. Each group is composed of 2 axial polarized ring piezoelectric ceramic disks. In group B, each of piezoelectric ceramic disks is splited into a half circle, and the two semi-circular is polarized in the opposite direction. Two piezoelectric ceramic disks are stacked in reverse polarity, and the arrangement is shown in Fig. 2.
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Fig. 2. The arrangement of piezoelectric ceramics
Adding AC electric field to group A, piezoelectric ceramic disks produce vibration from top to bottom (Z-axis). And adding AC electric field to group B, Piezoelectric ceramic disks produce bending vibration from left to right. X-axis and Z-axis vibration displacement:
x = a sin(2π ft ) z = b sin(2π ft + ϕ )
(4) (5)
In formula (4) and formula (5), a is amplitude for the X-axis, b is amplitude for the Z-axis, and ϕ is phase difference between the two directions. According to formula (4) and formula (5), equation of motion can be written as follows:
2 cos ϕ z2 b2 x2 + − xz = 1 2 2 2 2 2 b sin ϕ a b sin ϕ ab sin 2 ϕ
(6)
Required ultrasonic turning track can be obtained by adjusting the phase differernce of the AC electric field which is added to Piezoelectric ceramic disks.
4 Two-Dimensional Ultrasonic Turning Simulates Grinding, Honing Track Grinding technology has extensive application in precision machining and ultra precision machining [5,6,7]. The movement of disseminated abrasive is at random. This paper mainly simulates the motion trace of sedentary abrasive. The trajectory of a single abrasive grit is shown by Fig.3.
Fig. 3. Grinding, honing motion trace
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Tool vibration displacement on the X-axis is shown in formula (4). With the velocity υ , tool along the Z-axis does uniform linear motion, which is also called the feed motion. Then simulative trajectory is gotten, as shown in Fig.4. This track is similar to swing straight grinding motion trace which is shown by Fig.3(a). The parameters are obtained as follows: a
υ = 20m / min .
= 12 μ m , f = 20kHz , ω = 2π f = 1.257 × 105 rad/s ,
Fig. 4. Simulation trajectory
The AC electric field is added to group A and group B at the same time, and the phase difference of electric field is ϕ = π 2 . According to formula (4) and formula (5), the simulative trajectory is shown in Fig.5. The parameters are obtained as follows: a = 12 μ m , b = 16 μ m , f = 20kHz ,
υ = 20m / min .
ω = 2π f = 1.257 × 105 rad/s ,
Fig. 5. X, Z composition motion
Fig.5 is X-axis and Z-axis composition motion, a is major axis and b is the short axis. When the tool does elliptical motion in the XZ plane, it does uniform motion in a straight line or the feed motion at the same time with velocity υ = 20 m min along the Z-axis. Simulative trajectory is shown in Fig.6. This track is similar to spiral grinding motion trace which is shown by Fig.3(b).
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Fig. 6. Synthesis of complex movement
The motion trail is synthesised when ϕ = 0 , ϕ = π . According to formula (4) and formula (5), simulative trajectory is shown by Fig.7 and Fig.8.
Fig. 7. Motion synthesis (φ = 0)
Fig. 8. Motion synthesis (φ=π)
The tool does linear motion in the XZ plane. With the velocity υ = 0.6 m min , tool along the Z-axis does uniform linear motion, which is also called the feed motion. Simulative trajectory is gotten and shown in Fig.9 and Fig.10. Fig.11 is motion
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synthesis of ϕ = 0 , and is shown in Fig.3(c).
ϕ =π
. This track is similar to honing motiton trace which
Fig. 9. Synthesis of complex movement(φ = 0)
Fig. 10. Synthesis of complex movement(φ=π)
Fig. 11. Synthesis of complex movement (φ = 0 and φ = π)
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5 Two-Dimensional Ultrasonic Vibration Turning System Design In this paper, ultrasonic transducer uses sandwich piezoelectric ceramic transducer, which is proposed by the French physicist Langevin. This transducer can reduce the problems which are caused by firing and polarization, while reducing the frequency of the piezoelectric ceramic transducer [8]. Fig.12 is diagram of two-dimensional sandwich transducer, which consists of front shroud, back shroud, and piezoelectric ceramic. A stress bolt connects these three parts closely.
Fig. 12. Diagram of two-dimensional sandwich transducer
Transducer is symmetrical structure, the resonant frequency is 20KHz, and back shroud’s material is 45# steel, outside diameter is Ф55mm, inside diameter is Ф17mm, ( ρ1 =7.8g/cm3, C1=5.2×105cm/s, E1=200GPa); The total of piezoelectric ceramics is 5 and its materials use PZT-8, outside diameter is Ф55mm, inside diameter is Ф17mm and thickness is 5mm, ( ρ 2 =7.5g/cm3, C2=3.1×105cm/s, E2=113GPa). Front shroud’s material is aluminum, outer diameter is Ф55mm and inside diameter is Ф17mm, ( ρ3 =2.7g/cm3, C3=5.1×105cm/s, E3=75GPa). ρ is materials density, C is sound velocity, E is elastic modulus. The total of copper electrode is 5 and its thickness is 0.4mm. The length of back shroud is l1 and the length of front shroud is
l3 . l1 = l3 = 27.3mm
Composite conical horn is shown in Fig.13, which is made of aluminum, outside diameter is D4=55mm, inside diameter is D5=17mm, ( ρ 4 = ρ5 =2.7g/cm3, C4=C5=5.1×105cm/s, E4=E5=75GPa).
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D
D
4
5
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l5
l4
Fig. 13. Diagram of composite conical horn
Frequency equation: Nα − tan ( kl 4 + α 2 ) k α N −1 1 D tan α 2 = , α = × ,N = 4 k N l4 D5 tan kl 5 =
Displacement node
C
(7)
;
x0 : π ⎧π ⎪⎪ 2 −α2 ,kl5 < 2 kx0 = ⎨ ⎪kl4 + ⎛⎜ kl5 − π ⎞⎟ , kl5 > π 2⎠ 2 ⎝ ⎩⎪
Amplification factor
k =
ω
(8)
M:
M = N (cos kl4 −
α k
sin kl4 )
1 cos kl5
(9)
N is area factor and k is wave number. According to formula (7) and formula (9), the simulative curve is shown in Fig.14.
Fig. 14. The curve about kl4 and
M
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kl4 = 2.8416 , M max = 10.72 , l4 = 0.115m , kl5 = 1.275 , l5 = 0.052m , kl5 < π 2 , kx0 = π 2 − α 2 , x0 = 0.052m . Nodal plane places l5 = 0.052m from the big end of the cone.
6 Two-Dimensional Ultrasonic Vibration System Dynamics Simulation Piezoelectric ceramic uses Solid5 in ANSYS element library to establish solid model [9]. Solid5 is used in thermal, magnetic, acoustic, piezoelectric and analysis of three-dimensional coupled field. This unit has eight nodes, and each node has six degrees of freedom. As for the piezoelectric coupling analysis, Solid5 has large deformability. For others used Solid95. Its unit has 20 nodes and each unit also has X,Y,Z freedom. Solid95 is higher than Solid45, and it doesn’t reduce the accuracy of the case. Piezoelectric ceramic disks are made of PZT-8, and they are thickness polarization. The polarized piezoelectric ceramic is anisotropic, so it is different from isotropic materials. The dielectric constant matrix, the piezoelectric constant matrix and elasticity matrix are given as follows. Dielectric constant matrix
[ε ] F m :
0 ⎤ ⎡904 0 ⎢ [ε ] = ⎢0 904 0 ⎥⎥ ⎢⎣0 0 576 ⎥⎦
Piezoelectric constant matrix
[ e]
c
m3
(10)
:
0 −4 ⎤ ⎡ 0 ⎢ 0 0 −4 ⎥⎥ ⎢ ⎢ 0 0 13.4 ⎥ [ e] = ⎢ ⎥ 0 0 ⎥ ⎢ 0 ⎢ 0 10.3 0 ⎥ ⎢ ⎥ 0 ⎦ ⎣10.3 0
(11)
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Elasticity matrix
[C ] N m 2 : ⎡13.7 6.8 7.3 0 0 0 ⎤ ⎢ 0 13.7 7.3 0 0 0 ⎥ ⎢ ⎥ ⎢ 0 0 12.1 0 0 0 ⎥ 10 [C] = ⎢ ⎥×10 ⎢ 0 0 0 3.1 0 0 ⎥ ⎢ 0 0 0 0 3.1 0 ⎥ ⎢ ⎥ ⎣ 0 0 0 0 0 3.4⎦
(12)
The horn is a axial symmetry revolving body, and uses bottom-up model. The points generate lines, and lines generate a axial plane. The model of the two-dimensional ultrasonic vibration system is obtained by the axial plane rotated 360°around the axis. Free mesh is used to generate finite element mesh, which is shown in Fig.15.
Fig. 15. Finite element mesh
Mode extraction method is subspace iteration method, and the modal number is 10. In modal analysis, side surface of all nodes between piezoelectric ceramic and front shroud constrain Y displacement, as shown in Fig.16. The electrode voltage (V = 0) is coupled on upper and lower surface, which is shown in Fig.17.
Fig. 16. Constrained Y displacement
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Fig. 17. Coupled the electrode voltage
Through the modal operation, the free resonance frequency is 22255Hz in the short-circuit state. This is close to the theoretical calculation of 20kHz. By modal expansion analysis, The relative displacement nephogram is shown in Fig.18.
Fig. 18. Relative displacement nephogram
7 Conclusion Traditional ultrasonic vibration turning mechanism and the pros and cons of the processing are analysed in this paper. On this basis, the imitating grinding of twodimensional ultrasonic vibration turning is proposed. The structure of two-dimensional ultrasonic vibration transducer is different from the structure of traditional longitudinal ultrasonic transducer. Necessary grinding track and honing track can be obtained by changing the voltages that apply to piezoelectric ceramic. Meanwhile, the design methods of transducer and horn are given, and which realize the transducer and horn modal analysis by using finite element software. The research improves the machining precision, and makes the application of this technology possibly in ultraprecision machining.
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Acknowledgement. The authors gratefully acknowledge the financial support provided by the University-Industry Cooperation Project of Jiangxi Education Department (Grant No. GJJ09005).
References 1. Cao, F.: Ultrasonic Machining Technology. Chemical Industry Press, Beijing (2005) 2. Yuan, J., Li, X., Chang, D.: Press Ultrasonic Elliptical Vibration Cutting. Aeronautical Manufacturing Technology 4, 92–93 (2005) 3. Shaomoto, E., Moriwaki, T.: Study on Elliptical Vibration Cutting. Manufacturing Technology 43(1), 35–36 (1994) 4. Lu, Z., Yang, L.: Analysis and Simulation of Mechanism in Ultrasonic-Vibration Cutting Based on Dynamic Fracture Mechanics. Journal of Harbin Institute of Technology 40(9), 1400–1401 (2008) 5. Wu, H., Cao, L., Liu, J.: Analysis of Kinematic Geometry on Face Grinding Process on Lapping Machines. Mechanical Engineering 38(6), 144–146 (2002) 6. Chang, Q., Liu, Y., Ye, S.: Computer Simulation Technology for Precision Lapping Process of Workpiece. Computer Simulation 24(5), 249–250 (2007) 7. Tian, Y.B., Zhou, L., Shimizu, J.: Elimination of Surface Scratch/Texture on The Surface of Single Crystal Si Substrate in Chemo-mechanical Grinding (cmg) Process. Applied Surface Science 255(7), 4205–4211 (2009) 8. Lin, S.: Ultrasonic Transducer Principle and Design. Science Press, Beijing (2004) 9. Qi, J., Li, Z., Zhao, C., Huang, W.: Linear Ultrasonic Motor with Two Degree of Freedom Using Longitudinal and Bending Vibration Modes. Maxon Motor. 12, 18–19 (2005)
Study on Optimal Path Changing Tools in CNC Turret Typing Machine Based on Genetic Algorithm Min Liu1, XiaoLing Ding1,*, YinFa Yan1, and Xin Ci2 1
College of Mechnical and Electronic Engineering, Shandong Agricultural University, DaiZong Street NO.61, Tai’an City, China [email protected], [email protected] 2 Tai'an Falcon CNC Machine Co., Ltd., Tai’an City, China
Abstract. This paper is aimed to find the optimum path of CNC turret typing system to reduce the changing tools times and optimize tool movement routes to make up for the deficiency of CNC Turret Typing machine production efficiency. An uncertainty polynomial model is raised based on the asymmetric traveling salesman problem. And genetic algorithm (GA) is used to solve the path optimization problem. The optimization of path can minimize the moving tools times. Furthermore, the optimization problem is simplified to shortest distance between points. Fitness function, selection operator, crossover operator, mutation operator and other genetic operations are studied in this paper. In addition, the greedy crossover operator, the elite preservation strategy and the self-adaption strategy are imported in GA, which enhance the ability of finding the optimum and speed the efficiency. Finally, MATLAB simulation testifies that the algorithm is valid. The experiment result shows that the GA can shorten processing time and can reduce the air travel effectively without changing the machine's hardware through reasonable arrangement of the changing and moving tools path. As a result, the efficiency and precision of CNC turret typing system was improved availably. Keywords: CNC turret, Genetic algorithm, Path optimization.
1 Introduction To meet the demands of tracking and controlling the product quality for steel structure producers and understanding the products information for users, steel structure information identification has been paid more and more attention. In our country, engraving, stylus printing and typing are three main ways of steel structure information identification. Among them, engraving mainly adopts NC milling cutter engraving, laser mark and EDM shaping technology. For NC milling cutter engraving, the words, fonts and stroke can be adjusted by NC. But there are still some problems, for example, huge investment, short tool life and high expense. Laser mark, this technology is widely used *
Corresponding author. Tel.: 0538-8249833.
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in marking the small workpieces. However, when the word depth call for larger, the technology is very difficult to achieve and high cost [1]. EDM shaping is a mature and high precision technology, which demands greater coordinate travel, high efficiency and larger cost for the large steel structure [2]. Another stylus printing using dotmatrix marking method has higher printing speed and lower cost, but the lower print recognition rates and poorer visual effects, which is prone to cause mark misunderstand [3]. Steel structure typing, which make stamping characters more clear, is a kind of technique using ramjet power to impact the characters. Besides, the typing depth is easy to control, the tool is long life and low cost. At present, CNC turret typing is an advanced typing technology. The meachine with CNC turret typing can achieve a two-way rotary and nearby change tools anywhere [4]. The generation and optimization of the tools path in stamping process plays an important role. Efficient tool path optimization algorithm can reduce the tool traveling distance and can improve production efficiency. In the process of generating numerical code, the point is optimized by shortening the changing and moving path to reduce idle travel time, then can improve processing efficiency. Therefore, it is worth studied to select the reasonable processing path. The CNC turret typing system is characterized by high speed, high precision and wide moving range. The specific location and methods of the relative motion between tool and workpiece were described via tools path, including the effective stamping locus and the auxiliary locus [5]. The auxiliary locus which cost some processing time is mainly used for turret rotating positions and tool orientation, although they are not directly involved in shaping the workpiece. So optimize the auxiliary locus is needed. Due to the large auxiliary locus, the arrangement sequence is closely related with the processing path. It is very difficult to use the traditional method to search optimal path. In this paper, the path optimization based on the evolutionary algorithm is used to plan the auxiliary locus. On the basis of the reduction of the changing tools amount and optimization tools locus, The problem of optimal path changing tools is discussed and solved from another perspective. This assumption, not considering the machine fault and tool wear, permit us to believe only one same specification tool in CNC turret machine.
2 Basic Principle of Optimal Path Changing Tool and Modeling The changing tools time is longer than fast moving tools in CNC Processing, so it is very important to reduce the tools changing times to improve the processing speed. For the above reasons, the combinatorial optimization system is called for the least tools changing times firstly. The steps are as follows. Firstly, each tool changing one time must process the same characters completely without repeat and miss. Secondly, the tools change through turret nearby rotating to process others characters. How to arrange the processing paths to assure the least spare travel bring on a problem, which can be come down to the asymmetric traveling salesman problem (TSP) with additional constraint (that is, the least tool changing times). For example, a businessman wants to sell goods in n cities. How to choose a shortest path make the businessman go through the whole cities only once and return starting point [6]. TSP is a typical NP complete
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problem, which is easy to describe but difficult to handle. The classical and improved GA is an effective method for solving TSP so the method has been widely used. GA is a global search capability algorithm and is derived from evolutionism based on genetic selection and nature elimination of Darwin ism and genetics. The algorithm is leaded in selection, crossover and mutation, etc. Genetic processing is repeatly application in the population which contains all possible solutions. In the process, offspring groups adapt to the environment more than previous. The optimal individual can be viewed as the near optimal solution by decoding [7]. In CNC turret typing system, processing code is analyzed firstly. Then the paths after the tool changing once are as a path group. After changing the correspondence tool, the tool moves along the shortest air travel paths begaining with a given character. The next character is processed until all the same characters are processed, so circulates. Here, tools play a TSP role in fact, and character points play the role of cities. Furthermore, the goal is the shortest of tool’s air travel in processing.
3 Optimal Path Changing Tools Based on GA 3.1 About GA GA is a predominant all-round optimizing method in species evolution processin nature. GA makes question’s solution into a certain amount of initial chromosomes (initial solution) firstly. Secondly, the chromosomes are put into the problem environment. The well-adjusted chromosomes will be selected by the “survival of the fittest ” principle. Then the above chromosomes take the selection, crossover and mutation operation. Thus a new generation and more adapt to the environment of chromosomes will appear. So following evolution, the optimal solution will converge to an individual which most adapts to the environment finally. GA searches from one group to another and the method does not easily fall into the local optimal solution. In addition, the search process only depends on individual fitness function, so the method is very good robustness and extensive adaptability. 3.2 Overall Design of Optimal Path Changing Tool In this paper, GA is used to optimize the CNC turret changing tools path. Path optimization was simplified as the optimization from point to point by an encoding method based on path. The greedy crossover operator is designed, which has advantage of inheriting good chromosome from parent individuals and improving search capability. Furthermore, this algorithm uses norm geometry selection method and the elite preservation strategy to protect the outstanding individual structures of group, and the algorithm adopts the adaptive strategy to adjust the mutation probability dynamically, so the efficiency of the algorithm is improved greatly. The path optimization program of CNC turret typing system includes coding module, selection, crossover and mutation module, GA controls parameter module, initialization module, decoding module, fitness calculation module and so on. The overall design flowchart is shown in Fig.1.
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processing code analysis motion command tool path muster population initialization
mutation fitness evaluation
termination or not ?
crossover N
selection
Y
similarly most optimal solution new processing code Fig. 1. Flow diagram of the program
3.3 Realization of GA The working process of the GA mainly includes three types of operation, such as the chromosome coding and structure primitive group, the fitness calculation method and the selection, crossover, mutation operation method. The maximum number of generations termination criterion is adopted in GA and selected the viable path with the best fitness. 3.3.1 Chromosome Coding and Structure Primitive Groups The path coding form includes binary representation, adjacency representation, ordinal representation, path representation, matrix representation, edge representation and so on. GA mostly use particular gene representation composed of binary code, but for TSP scheduling problem, path representation is used usually. This is the nature and simplest method in path coding and it is a real number coding. Changing tools serve as the processing technology routing according to the combinatorial optimization goal. Tool is changed one time as a process group which is expressed as a chromosome group. Grefenstette path representation is adopted in coding chromosome which can ensure that any individual has practical significance [8]. The path representation describes as follows. The Nth changing tool consists one process group W. The processing sequence in W is assumed in formula (1). o = (t1 , t 2 , t 3 ,..., t n ) .
(1)
The rule is that once the process completed must move away from the group. The corresponding operation sequence of the Ith process t i is mi (1 ≤ mi ≤ n − i + 1) in all
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unprocessed groups W − {t1 , t2 ..., ti −1} . The operation sequence is as for the process group coding in the chromosome. So a list M of chromosome is got after dealing with all steps in formula (2). M = (m1 , m2 , m3 ,..., mn ) .
(2)
3.3.2 Fitness Function The fitness is the only criterion to judge whether the individual is good or not in GA. Optimal path changing tools in CNC turret typing system uses minimum tool moving locus as target function on the premise of the least changing tools times. Therefore, the corresponding fitness is shown in formula (3) for any chromosome T. F (t ) = 1 / ∑ i
∑
d ij u ij .
(3)
j
In the above equation, d ij shows the distance between the character i and j. u i j shows whether the tool travels from the point i to j. If "yes", its value is 1, "no" is zero. 3.3.3 Design the GA Operator GA operator includes selection, crossover and mutation operator. Reasonably choosing operator can prevent premature convergence and can accelerate the search speed. In the operation of GA, these operators make the group ceaseless evolving and move towards the optimal solution gradually. 1 . Selection operator. The operator is used to perform the operation of selecting the ƻ superior and eliminating the inferior for the individuals in group. Then the operator can determine how to select some individuals to inherite from the father generations to child. Due to the best chromosome not always appear in the last generation, the best chromosome is preserved at the beginning. Once the new group finds a better chromosome which is used to replace the original. After completion of the evolution, the last chromosome can be regarded as the optimization result. Therefore, this algorithm uses norm geometry selection and elite preservation strategy which can protect the excellent individual structure in evolutionary process. The selection mathematical model is described in formula (4). Suppose the number of individuals is n, the fitness value of one individual i is F(i) , so the probability of i selected is Psi . n
Psi = F i / ∑ F j . j =1
(4)
Ps i reflects the fitness value of individual i occupying the proportion in the sum of fitness at the whole group. 2 . Crossover operator. Due to use Grefenstette path coding, genotype individual ƻ from GA is able to correspond a practical processing sequence. So we can use usually single point or multi-points crossover operator which determines the global search ability of GA. Many kinds of crossover operators are combined use in the algorithm. In
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particular, GA is characterized by poor convergence, so the greedy crossover operator is introduced to accelerate convergence speed. 3 . Mutation operator. The role of mutation operator is to maintain the population ƻ diversity and improve algorithm local searching ability. The mutation operation adopted in this algorithm random produces a character number as the first processing character. In this way, the typing path is changed according to the above method. Then the phenomena of premature convergence can be prevented by adaptively adjusting the mutation probability. 3.4 Operation Parameter The operation parameters selected in GA include group size, individual coding length, crossover probability, mutation probability, biggest evolutionary algebra, etc., which influence the GA performance greatly. For the specific problem, whether the parameter setting is fitting or not, is judged by multi-Processing convergence condition and the quality of solutions.
4 Application and Sample If one tool of the CNC turret center has 31 points, now we should optimize the process coding to make the path shortest after processing the same characters under the condition of not changing tool. The parameters of optimization path algorithm are as following. The group size is 40, maximum evolutionary algebra is 500, crossover probability is 0.6, mutation probability is 0.05, self-adapted mutation parameter k=1, the elite number is 2. At last, using GA optimization toolbox (GAOT) to simulate the whole trajectory. GAOT in MATLAB is used to verify the GA efficiency. GAOT’s genetic operations is very flexible and provide reliable, extensible exploration platform for application and research GA. Program is as following, then the optimized path is shown in Fig.3. clear all global distMatrix t=[1300 2302;3659 1415;4107 2144;2712 1799;3688 1635;3826 1156;2238 1229;5196 1044;2312 790;3386 570;3007 2970;2562 3756;2688 1991;2361 1776;1332 2695;3715 2678;3918 2179;4061 2370;3780 2212;3676 2578;4029 2838;4263 2931;3429 1908;3507 2376;3394 2643;3439 3201;2935 3240;3140 3550;2545 2357;2778 2826;2370 2975]; sz=size(t,1);distMatrix=dists(t,t); xFns ='cyclicXover uniformXover partmapXover'; xOpts=[2;2;2]; mFns ='inversionMutation adjswapMutation shiftMutation swapMutation threeswapMutation'; mOpts=[2;2;2;2;2];termFns='maxGenTerm'; termOps=[500];selectFn='normGeomSelect'; selectOps=[0.08];evalFn='tspEval'; evalOps=[ ];
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bounds=[sz];gaOpts=[1e-6 1 1]; startPop=initializeoga(80,bounds,'tspEval',[1e-6 1]); [x endPop bestPop trace]=ga(bounds,evalFn,evalOps,startPop,gaOpts,termFns ,termOps,selectFn,selectOps,xFns,xOpts,mFns,mOpts); bestPop trace plot(trace(:,1),trace(:,2)); hold on plot(trace(:,1), trace(:,3)); figure(2) clf A=ones(sz,sz); A=xor(triu(A),tril(A));[xg yg]=gplot(A,t); clf h=gca;hold on ap=x; plot(t(x(1:sz),1),t(x(1:sz),2),'r-'); plot(t([x(1),x(sz)],1),t([x(1),x(sz)],2),'g-'); plot(xg, yg,'b.','MarkerSize',24);
Fig. 2. Tool path chart after using standard GA to optimize
Fig. 3. Tool path chart after using improved GA to optimize
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Fig. 4. Tool path optimum and average value after using GA to optimize
The simulation result is shown in Fig.3 and Fig.4. Fig.2 shows tool path after using standard GA to optimize, the total distance is 18572.231687. The tool path after using improved GA is shown in Fig.3, the total distance is 16116.820139. The air travel distance shorten 13.22% compared with the standard GA. Obviously, the import of the greedy crossover operator, the elite preservation strategy and the self-adaption strategy improved the standard GA very successfully in this paper. Furthermore, the ability of finding optimum is improved and the improved GA obtains the optimum at the thirtieth generation first time. From Fig.3 it can be seen that tool path is improved obviously after optimization. CNC turret path is optimized on the premise of minimum changing times, because changing tools will waste more time than fast moving. As a result, the redundant tool locus is reduced and the processing time is saved greatly. Optimal path changing tool in CNC turret typing machine based on GA obtained a good optimize effect.
5 Conclusions In this paper, we describe the practical problems in CNC turret typing system and use the improved GA to find optimal tool path. According to give priority to change tools at the least number of path optimization, the problem is converted to TSP problem with constraint condition firstly. Then the selection, crossover and mutation operator and fitness value are studied separately. A view of the simulation results can be obtained from here. This method used GA succeeded in optimizing the CNC turret typing path. These operations can effectively solve the tools air travel problem in the multi-point processing. It can not only shorten the processing time but also make up for the deficiency of production efficiency of CNC Turret Typing machine. It can be seen that this method is effective, feasible on the path optimization problems and has laid a foundation for further research. But, by virtue of introducing special constraint, genetic algorithm generality is restricted which is the main emphasis of the future research. Acknowledgement. The authors would like to acknowledge ShanDong Provincial Education Department Scicence & Technology Project for their financial support (J09LD22). The authors also would like to acknowledge Tai'an Falcon CNC Machine Co. for providing the excellent environment and the experiment facility.
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References 1. Fang, Q., Cai, D., Qian, B.: Marking Path Optimization Algorithm for Laser Marking and Application. Applied Laser 8, 290–293 (2009) 2. Xie, Z., Xiao, Y., Han, Z.: EDM Lettering Technology of Large-scale Workpiece’s Surface. Journal of Chongqing University 5, 14–17 (2003) 3. Chen, x., Xu, w.: Design of Print Head of Steel Plate Pin-printer and Analysis on the Priciple of Its Print Sign Forming. Metallurgical Equipment 4, 53–56 (2003) 4. Luo, H., Dong, H.: GA-based Approach to Optimize Cutters Arrangement on the Turret Post of Turning Center. Agricultural Machinery 2, 172–175 (2007) 5. Erkan, Ü., Mehmet, E.T., Selçuk Halkaci, H.: An artificial immune system approach to CNC tool path generation. J. Intell. Manuf. 20, 67–77 (2009) 6. Zhou, Z., Ding, T.: Research on Holes Machining Path Planning Optimization with TSP and GA. Design and Research 7, 30–32 (2007) 7. Chen, J.C., Zhong, T.X.: A hybrid-coded genetic algrithm based optimisation of non-productive paths in CN machining. The International Journal of Advanced Manufacturing Technology 20, 163–168 (2002) 8. Yu, W., Fu, J., Chen, Z.: Approach optimizing tool paths arrangement based on genetic algorithm. Journal of Zhejiang University (Engineering science) 40, 2117–2121 (2006) 9. Zhang, L., Wu, T.: Path optimization on laser drilling based on genetic algorithm. Mechanical & Electrical Engineering Magazine 24, 77–79 (2007) 10. Qu, J., Xiao, S.: PCB drilling path optimization based on ant-coIony aIgorithm. Mechanical & Electrical Engineering Magazine 24, 56–58 (2007) 11. Ma, Z.M., Huang, L.: The Optimization Algorithm of Holes Machining Path With Datum Hole. Machine Tool & Hydraulics 36, 28–32 (2008) 12. Xuan, D., Li, Z.: Component Placement Process Optimization for Chip Shooter Machine Based on Genetic Algorithm. Journal of XI’AN JiaoTong University 42, 295–299 (2008) 13. Ramli, R., Abu Qudeiri, J., Yamamoto, H.: Tool Path of Lathe Machine in Flexible Transfer Lines by using Genetic Algorithms. In: IESM 2007, Beijing-China, May 30-June 2 (2007) 14. Ugur, A.: Path planning on a cuboid using genetic algorithms. Information Sciences 178, 3275–3287 (2008) 15. Xing, L.-N., Chen, Y.-W.: A hybrid approach combining an improved genetic algorithm and optimization strategies for the asymmetric traveling salesman problem. Engineering Applications of Artificial Intelligence 21, 1370–1380 (2008) 16. Singh, A., Baghel, A.S.: A new grouping genetic algorithm approach to the multiple traveling salesperson problem. Soft Compute 13, 95–101 (2009) 17. Makhanova, S.S., Batanovb, D., Bohezb, E., Sonthipaumpoonc, K., Anotaipaiboona, W., Tabucanond, M.: On the tool-path optimization of a milling robot. Computers & Industrial Engineering 43, 455–472 (2002) 18. Lee, S.-G., Yang, S.-H.: CNC Tool-Path Planning for High-Speed High-Resolution Machining Using a New Tool-Path Calculation Algorithm. Int. J. Adv. Manuf. Technol. 20, 326–333 (2002) 19. Castagnetti, C., Duc, E., Ray, P.: The Domain of Admissible Orientation concept: A new method for five-axis tool path optimisation. Computer-Aided Design 40, 938–950 (2008) 20. Oysu, C., Bingul, Z.: Application of heuristic and hybrid-GASA algorithms to tool-path optimization problem for minimizing airtime during machining. Engineering Applications of Artificial Intelligence 22, 389–396 (2009)
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21. Zhuaa, L., Gang, Z., Han, D., Xiongb, Y.: Global optimization of tool path for five-axis flank milling with a conical cutter. Computer-Aided Design 42, 903–910 (2010) 22. He, W., Lei, M., Bin, H.: Iso-parametric CNC tool path optimization based on adaptive grid generation. Int. J. Adv. Manuf. Technol. 41, 538–548 (2008) 23. Moriwaki, T., Tangjitsitcharoen, S., Shibasaka, T.: Development of intelligent monitoring and optimization of cutting process for CNC turning. International Journal of Computer Integrated Manufacturing 19, 473–480 (2006)
Study on the Problem and Countermeasure of Fruit Production Quality and Safety in Yanshan Mountain Haisheng Gao, Bin Du, and Fengmei Zhu School of Food Science and Technology, Hebei Normal University of Science and Technology, 066000 Qinhuangdao, P.R. China
Abstract. In this paper, the main problem and countermeasure of fruit production quality and safety were studied in Yanshan Mountain. The subjective factor was fruit farmer quality and safety consciousness faint, and the objective factors were: severe orchard environmental pollution, faint fruit post-harvest handling, lag in process technology, fruit quality determination and market inspection system is not yet perfect. The measures of improving fruit quality and safety production in Yanshan Mountain were proposed. On the premise that adjusting and optimizing regional distribution, building and improving quality and safety production management system, controlling post-harvest handling and circulation contamination, implementing organic strategy, establishing Green Silicon Valley. Keywords: Yanshan Mountain, Fruit quality, Fruit safety production, Problem, Countermeasure.
1 Introduction
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The center of Yanshan mountain is 39°45′ 41°N 115°40′ 119°50′E. Yanshan Mountains are a major mountain range north of the North China Plain, in northern Beijing, Tianjin and Hebei Province. The length of Yanshan Mountain is 330 Km from east to west, 120 Km from south to north. Yanshan Mountain has a marked continental monsoon climate. The average annual sunlight is 2600 2800 hours. The mean annual precipitation of this region is 607.5mm. It is suitable to plant fruit trees in the hilly region and the plain. The main fruits are: apple, pear, grape, hawthorn, chestnut, walnut, jujube, peach, apricot, plum, cherry and so on [1]. With the rapid development of science and technology and modern industry and the progress of human civilization, it is becoming increasingly clear of the awareness for the industrial pollutants and drug residue by food chain are harmful to human health and it is increasingly intensive for demand of fruit safety. What is more, the agricultural product quality and safety is the hot issue of government attention, social attention and global focus. The fruit product quality and safety is also the key problems of implementing the agriculture and rural economy structure adjustment and improving international competitiveness of fruits. So, it is significant for improving fruit production quality and promoting fruit industry development by carrying out fruit production quality and safety in Yanshan Mountain and strengthening environment control. This
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paper for the first time reports the problem and countermeasure of fruit production quality and safety in Yanshan Mountain.
2 The Problems of Fruit Production Quality and Safety in Yanshan Mountain 2.1 The Weak Quality and Safety Awareness of Most Fruit Farmers The fruits production makes the family as the basic unit in China nowadays. The decision subject of production management is farmer. They were lack of safety awareness and the legal system because they were restricted by the cultural level and technical condition, and stimulated by the economic interests. In orchard management, they fertilize more chemical fertilizer and less organic fertilizer, more nitrogen fertilizer and less phosphate and potash fertilizer. They rely mainly on chemical pesticides for pest control. And in the eradication of pests but also kill the natural enemies of pests by improper application. They have to use high toxic pesticide residues due to the increasing pest resistance. All of this leads to rapid deterioration of the orchard ecological environment and over standards of fruits pesticide residue. 2.2 The Growing Problems of Environmental Pollution in Orchard In recent years, with the development of modern industry, the dramatic increase of industrial wastewater, exhaust and residue emissions leads to deterioration of the orchard ecological environment and poor fruit growth and development and lower fruits production. Accumulation of toxic substances in fruits results in decreased safety and quality, even some fruits can not eat. In addition, the extensive use of agricultural chemicals, fertilizer and herbicide in some production areas causes the dramatic decrease of atmosphere, water and soil quality and the deterioration of ecological environment, and fruits serious pollution. 2.3 The Faint Treatment of Fruits Commercial Post-harvest The fresh fruits achieve fast development recently. The fresh fruits post-harvest would dehydrate and shrink, the flesh would brown. The fruits would be rot in preservation and transportation. Relatively, the cultivation before harvest was taken seriously in China fruits production, and the post-harvest treatment was neglected. The treatment of fruits commercial post-harvest and cold chain circulation seriously lag. The facilities condition of preservation and transportation is poor. There are some pollution problems in the treatment of fruits commercial post-harvest and preservation, transportation and sale. For instance, not strict fruits grade, simple and rough package, improper preservation and transportation management measures and unscientific disease control in preservation. All of this not only aggravate the fruits decay losses in post-harvest circulation, but also affect fruits quality and safety [2]. 2.4 The Relative Backward Processing Technology In addition to juice and wine production, other fruits production is based mainly on middle and small enterprises in China at present. These enterprises have poor processing
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facilities conditions, low processing capacity, defective fruit as raw material, low scientific and technological content in production, low added value and unstable quality. There are irregular operations and not complete cleaning and sterilization in some fruits production enterprises. These lead to microbiological contamination by yeast, lactic acid bacteria and mould, further lead to over standard of microorganism. At the same time, there are some problems such as irregular additive application, over standard in fruits production. The cleaner in fruit washing and the disinfectant in packaging sterilization also cause chemical hazards. 2.5 Imperfect Quality Determination and Market Inspection System The building of test organizations lags in China. Most provinces can not detect the pesticide residues. The building of fruit market test organizations is very weak. There are few instruments and inspectors in farmers market and fruits market. In addition, the detection methods were still lagging behind, the detection efforts are not enough, and the detection standard can not conform to international standard.
3 The Countermeasures of Fruit Production Quality and Safety in Yanshan Mountain 3.1 Adjusting and Optimizing Regional Distribution The regional culture is a basic condition achieving fruits safe production. Planting fruit trees in unsuitable areas is not only affecting species characteristics, but applying complicated fertilization and spraying because of pursuit of high quality. These increase pollution links and make fruits safety worse. The important mark of fruits trees production modernization is adjusting structure, optimizing fruits trees distribution, improving product composition and meeting market demand. The optimizing and adjusting fruits trees structure is adjusting species structure. On the one hand, the specific measures are: with the combination of mountain and plain green, selecting less pollution hilly and sandy beach land, developing adaptable ecology forest and forest net, fruit crop intercropping, controlling the development of large amount of fruits, developing famous dried fruits, adjusting early maturing, maturing, late maturing variety, supplying reasonable market. On the other hand, regional adjustment is the crucial measure. In accordance with the principles of tree species selected for suitable planting site, gradually realizing regional culture of fruits trees. 3.2 Building and Improving Quality and Safety Production Management System The actual situation of current fruits production is thousands of households decentralized management. Building the perfect safety production management system, regulating production activities and technical measures, reducing the infection of harmful substances and achieving safety production are important. The four measures are as follows:
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1. The key technologies are environmental technology system, production technology system and quality standards technology system. 2. The environmental quality monitoring system includes the non-pollution environmental monitoring system of water, soil, atmosphere and Living creature. 3. The regulations systems include building produce quality and safety detection and monitor system and produce quality regulations system. 4. The service system includes organizing or supporting the management system combined with farmers, firms, technology demonstration base and market, turning service for agricultural production into service for agricultural products, integrating the agricultural efficiency with economic benefits. 3.3 Controlling Post-harvest Treatment and Circulation Contamination The fruits post-harvest mechanization commercial treatment accounts for 5% at present, while the fruits post-harvest losses account for 20%. Post-harvest treatment is the bottleneck of restricting fruits into high ranking market [3]. Therefore it is very important for us to intensify fruits post-harvest treatment, formation production cooperatives, implement the measures—decentralized production, centralized grading and packaging and centralized sale, enhance the competitiveness of Chinese fruits in international market. The major measures are as follows: the first is pre-cooling. The pre-cooling is essential for fruits post-harvest in place of production. The role of precooling is dispersing heat of fruits, lowering metabolic intensity and maintaining the freshness of fruits. The second is grading. Excluding disease fruits and mechanical injury fruits, then reasonable grading was applied according to fruits shape, color, freshness for transportation, storage and sale. The third is washing and waxing. The steps are washing the dirt, pesticide, oil and germ by fruits detergent, then showering using water and drying in the air. The wax of fruits was destroyed by washing. The fruits would loss water in storage and transportation. So treating the fruit surface by wax, shellac, starch film and sucrose membrane. This treatment could maintain the freshness and nutrition of fruits and beautify fruits. The fourth is storage and preservation. The fruits would be rot by the germ infection, so using the preservative is essential before storage. The natural biological agents and herbal extracts, are selected as antiseptic, preservative and packaging. The fifth is package. The package is favorable to protect fruit, facilitate transportation and storage and facilitate the purchase. It is important for package to guarantee fruits safety transportation and sale. Especially export fruit, the package quality and tactics are crucial. The carton should be treated using disinfectant. The sixth is proposing food quality traceability system and food market access system to effectively protect the legitimate rights and interests of producers and consumers. In the circulation, the industrialization management should be paid attention to. Building industrialization mechanism is the important content of developing modern fruit production and also is the essential measure of reducing fruits pollution links, building fruits safety production system. Therefore, the first is to develop value added processing and market building, nurture leading enterprises. The second is to strengthen the connection of leading enterprises, base and farmers. The third is to build the matching management system and operation mechanism, realize scale operation, scientific management and social service, build the new pattern of forest
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industry development of production, supply and sale, maintain the sustainable development of fruits industry. 3.4 Implementing Organic Strategy There are two patterns of global agricultural development: On the one hand, the conventional agriculture is extensive use of fertilizers, pesticide. The pursuit of this pattern is economic objectives. Conventional agriculture is the main form of agriculture nowadays. On the other hand, Organic agriculture is the form that excluding or strictly limiting the use of chemical compounds. The pursuit of organic agriculture is combination of economic and ecological benefits. Organic agriculture is the development direction of modern agriculture [4,5]. The product of organic agriculture is organic food. Organic food is a kind of sustainable food. The goal is environmental protection, safety, health, quality. Organic strategies must be implemented and organic fruit production must be progressively developed. So the safety of fruits is ensured fundamentally. Implementing the organic strategies is a gradual process. On the basis of improve pollution-free fruit and green fruit, developing organic fruits step by step. The current main tasks are as follows: the first is improving environment and environmental protection; the second is reducing fertilizer application, promoting application of organic fertilizers and microbial Fertilizers; the third is promoting biological control technology, using biological pesticides or non-pollution pesticides, improving the credibility of the fruits in Yanshan Mountain. 3.5 Establishing Green Silicon Valley The development of fruits safety production should learn experience from “Silicon Valley”, and strengthen scientific and technological research and practical technical reserves. Building green fruits production base, and making it as fruits production test with high technology, the base of senior technical personnel, the place of practical technology, the model base of organic fruits and safety production. Depending on the example of green Silicon Valley, and promoting the development of national fruits safety production, ensuring the long-term development of fruits production in Yanshan Mountain.
4 Conclusions In a word, Yanshan Mountain has unique advantage of producing high quality fruits. However, there are low level of farmer organization and deep traditional business. Industrialization is the primary measure of activating fruits industry development. In accordance with the requirements—uniform production technology, uniform product standards, uniform monitoring method, uniform management measures and uniform pesticide regimen. Building a group of green fruits production export demonstration garden and promoting the development of national fruits safety production. Strengthening the construction of fruits pesticide residue monitoring network system and building regular fruits pesticide residue monitoring system are crucial. Putting Emphasis on fruits production base, fruits wholesale market and fruit operation
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market circulation, equipping with instruments and equipment in processing, enriching the test personnel, improving test level, expanding test project, implementing the market access system. The aim is implementing the measures such as emphasis on investment, building base, controlling heading enterprises, connecting farmers and developing market, and putting Yanshan fruits industry business into the development track of industrialization.
References 1. Science and Technology Department of Hebei Province: Characteristic industry science and technology development planning in rural areas in Yanshan mountain, Hebei Province. Development planning writing group. pp. 1–3 (2008) 2. Haisheng, G., Xiyan, Z., Runfeng, L.: Review of post-harvest treatment and preservation technologies of fruit and vegetable. Trans. CSAE 2, 273–278 (2007) 3. Haisheng, G., Runfeng, L., Xiufeng, L.: Advance in Past-havest Commoditization Processing Technologies of Horticultural Products. Food Sci. (in Chinese) 9, 627–631 (2008) 4. Xiaogui, S., Qingdang, G.: Discussion of Fruit Security in Shandong Province. Nonwood forest res. 1, 68–70 (2004) 5. Fengtian, Z., Yang, Z.: China Food Security: Problems and Policy Measures. China Soft Sci. 3, 16–20 (2003)
Calculation and Analysis of Double-Axis Elliptical-Parabolic Compond Flexure Hinge* Ping’ an Liu1, Jianqun Cheng1, and Zhigang Lai2 1
School of Mechanical and Electronic Engineering at East China Jiaotong University, Nanchang 330013, China [email protected] 2 Jiangxi Technical College of Manufacturing, Nanchang, Jiangxi, 330095, China
Abstract. A double-axis flexure hinges combined with elliptical and parabolic curve is presented in this paper. The design equations for its compliance computation have been deduced by application of Castigliano’s displacement theorem after the anlysis of the structure, which were analyzed by the use of the software MATLAB, and comfirm the validity of the model with finite element analysis software ANSYS. Keywords: flexure hinge, mixed flexure hinge, compliance, Castigliano’ theorem.
1 Introduction Flexible hinge eliminates its idling running and mechanical friction by using small angle elastic deformation and self-recovery characteristics in the transmission process, and can get highter resolution of displacement. It is been widely used in various occations, such as small angular displacement, high-precision rotation of occasions, especially in precision measurement, positioning and other fields because of its small-volume, gapless, no mechanical friction,no lubrication, in-gage and high sensitivity of the transmission structure [1-3]. People have been made a series of studies on the single-axis oval, chamfered, parabolic and hyperbolic flexure hinge [4-5] since 1965 Paros and Weisbord derived circular flexure hinge flexibility formul. However, they have done little reaserch about the compound flexure hinge in addition to Chengui Min’s [6] on the right circular and oval compound flexure hinge. Elliptical flexible hinge has a lager range of rotation but lower accuracy, and Parabolic with small range of rotation but high precise compared to the Circular incision hinge; for both accuracy and range of motion exercise, combining the elliptic and parabolic type flexure hinge will take the advantages of both flexible hinges, so this paper will present elliptic - parabolic compound flexible hinge. *
Supported by Natural Science Foundation of Jiangxi, China, NO. 2008GZC005.
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2 Elliptie-Parabolic Compound Flexible Hinge Elliptic and parabolic confound flexible hinge is composed of two half elliptical and parabolic form, as shown in figure1, oval-side as a fixed end and the Parabolic side as the rotation-side, and make the following assumptions: (1) (2) (3) (4)
Elliptic and parabolic incision have the same thickness,and both are t. Elliptic and parabolic are tangented at the intersection, or smooth over. Two incision length in the X direction are m. Ellipse major axis m is greater than the minor axis n, when m=n,that is circurlar and parabolic compound flexible hinge.
Fig. 1. Elliptic-parabolic hinge pro/e model
Fig. 2. The structure parameters of compound hinge
3 Flexibility Formulas Assumptions based on cantilever small deformation,bending deformation is generated by the force and moment. The impact of axial load has considered, while the impact of shear and torsion were not. The structure parameters of axial elliptic - parabolic compound flexure hinge were shown in Figure 2,and the force analysis as shown by
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Figure 3, the flexibility formulas of compound hinge were deduced based on mechanical card's second theorem:
Fig. 3. The force analysis of compound hinge
⎧θz1 ⎫ ⎧Cθ −M C12 0 ⎫⎧Mz1 ⎫ ⎪ ⎪ ⎪ ⎪⎪ ⎪ ⎨y1 ⎬ = ⎨ C12 CY 0 ⎬⎨Fy1 ⎬ ⎪x ⎪ ⎪ 0 0 CX ⎭⎪⎪⎩Fx1 ⎭⎪ ⎩1⎭ ⎩
(1)
According to reciprocal theorem known θz1 =C11Mz1 +C12Fy1,it can be obtained from the left of formula (1) with the use of cartesian displacement:
⎧ ∂u ⎪θz1 = ∂Mz1 ⎪ ⎪⎪ ∂u ⎨ y1 = ∂Fy1 ⎪ ⎪ ∂u ⎪ x1 = ∂Fx1 ⎪⎩
(2)
By the material mechanics, without considering the shear and torsion, the deformation energe of the compound flexible hinge is:
U=
⎤ 1 ⎡ FX 12 MZ2 dx + dx ⎥ ⎢∫ ∫ 2 ⎣ l EA( x) EI z ( x) ⎦ l
and F x = F x 1 , M z = M z1 + Fy1 x , A( x) = bt( x) , I ( x )
=
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(b t ( x ) ) / 1 2 3
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The coordinate system as shown in figure 2, variable thickness equations of dual-axis flexure hinge as follow:
⎧ ⎡ n 2⎤ ⎪⎪ t +2⎢n−m 2mx−x ⎥ ⎣ ⎦ 0≤x≤m t(x) =⎨ 2 ⎪t +2⎡2p( x−m) ⎤,m<x≤l ⎪⎩ ⎣ ⎦
(4)
To the type of substitution (1) (2) (3) can obtain the flexibility formulas: ⎧ ⎛ 2n + t ⎞ ⎫ ⎪ −π −t(4n + t) − (8n + 4t) Arc tan ⎜⎜ ⎟ Arc tan( 2m p ) ⎪ −t(4n + t) ⎟⎠ 1 ⎪ ⎪ t ⎝ CX = ⎨m* + ⎬ EB ⎪ 4n −t(4n + t) 2 pt ⎪ ⎪ ⎪ ⎭ ⎩
CY =
3 4 3 2 2 3 4 ⎛ −4nt −t2 ⎞ 12 ⎧⎪ 3 16c ( −80c + 24c t +8c (3+ 2π)t + 4c(1+ 2π)t +πt ) 3 (2n +t)3 (6n2 − 4nt −t2 ) +m Arc tan⎜ ⎟ ⎨m 2 5 3 2 ⎜ ⎟ EB ⎪ t 16c t ( 4c +t ) ⎝ ⎠ ⎩ 4n3 ( −t ( 4n +t ) ) 2
m (1 1 2 p 2 m 4 + 5 6 p m 2 t − t 2 ) + + 32 p 2t 2 (4 pm 2 + t)2
Cθ − M
(5)
(1 2 p m 2 + t ) A r c ta n ( 3 2
64 p t
(
2m
5 2
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2 ⎛ 2n + t ⎞ m 12 pm + 5t 6n ( 2n + t ) 12 ⎧⎪ 6n 2 + 4nt + t 2 = − m Arc tan + + ⎨m 2 5 2 ⎜ ⎟ EB ⎩⎪ t ( 2n + t )( 4n + t ) 2 ⎝ −4nt − t 2 ⎠ 8t 2 4 pm 2 + t −4nt − t 2 2
(
)
(
)
t
p ⎫ )⎪ ⎪ ⎬ ⎪ ⎪⎭
(6)
2m p ⎫ )⎪ ⎪ t ⎬ 5 ⎪ 2 16 pt ⎪⎭
3 Arc tan(
(7) From the formulas of elliptical-parabolic compound hinges which have deduced, it can easily see that the flexibility is inversely proportional to the thickness B and modulus of elasticity E. 3.1 The Verification of Closed-Loop Compliance Formula Design two dual-axis elliptical – parabolic compound hinges, its parameters as follows: thickness B is 5mm, length of oval long axle 5mm, the minor axises 3mm and 5mm, the thinnest thickness in the middle is 1mm, the total width 10mm. FEM experimental parameters are: modulus of elasticity: E = 110 ×109Nm- 2
,Poisson ratio: μ= 0. 3.
parabol parameters: p=1/16 Fx1 = Fy1 = 1 N Mz1 = 1 N.m.
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Fig. 4. The ansys geometric model of compound
Models with different parameters in the finite element software to verify compliance formulas, choose the shell63 finite element, making finite element analysis to compound flexure hinge( As shown in figure 4), analytical method(AM) and finite element results were shown in Table 1. Known from the data in the table, finite element method(FEM) and the exact formula is less than 10% deviation.
Table 1. Analytical and finite element calculation about flexibility
3.2 Performance Analysis From the formulases (5) to (7),it is easy to know that the formula of flexibility is inversely proportional to modulus E and thickness B; the relationship between the CX, CY, Cθ-M and the short axis length n incision thickness t were shown in figure 5-7.
、
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Fig. 5. The relationship between Cx and n
、t
Fig. 6. The relationship between Cy and n
、t
Fig. 7. The relationship between Cθ-M and n
、t
(1) We can see from figure 5, the relationships between the flexibility of x-axis direction Cx and t, n are in the overall smooth, keep the t unchanged, with the increase of n, Cx will decrease linearly; if the n unchanged, Cx decrease with t increases and changes in relatively fast as t in the range of 0.2-0.4, Cx changes in relatively fast ,in conclusion the stiffness of X axis is large relatively.
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,
(2) The relationship between flexibility Cy and t n as shown in Figure 6 Cy will reach maximum when t equals to 0.2,and Cy will change sharply as t in the range of 0.2-0.4 and decrease smoothly when t is greater than 0.4, Cy has no significant change with n. (3) From the figure 7,we can see that the Cθ-M obtains maximum when t equals to 0.2 and decreases as n increase,especiallly when t in the range of 0.2-04, it decreases sharply; when t is greater than 0.6,the Cθ-M decreases slowly and close to zero. From the anlysis above all,this conpound hinge has large rigidity in the direction of x –axis and good flexibility in y axis direction and rotate around Z axis,so it is very suitable as rotation flexibility hinge.
4 Conclusions This paper presents a new type of compound hinge oval - parabolic compound flexible hinge. And analized its structure, its flexibility formulas were deduced based on card's second law and vertified by the finite element software,find the errors are within 8%, which demonstrates the correctness of the flexibility formulas. Then analyzed the relationship between the flexibility and the thickness B and the short axis lengh n with matlab software,and got some conclusions, it could be a theoretical references in future industry and agriculture fields.
References 1. Li, J., Wang, J.-W., Chen, K., and so on: Based on generalized geometric error model of the micro-robot accuracy analysis. Tsinghua University (Natural Science) 4(5), 28–32 (2000) 2. Fu, P., Zhou, R.-K., Zhou, S.-Z., et al.: Synchrotron radiation beam line in the flexible hinge of [J]. Optics and Precision Engineering 9(1), 67–70 (2001) 3. Sun, L.-N., Li, M.: A kind of two-dimensional micro-nano positioning stage design and analysis. Optics and Precision Engineering 14 (2006) 4. Feng, C., Xia, J.: Biaxial elliptical flexure hinge design and calculation. Engineering Mechanics 24(4) (April 2007) 5. Chen, J., Liu, P.: Cosh flexible hinge stiffness is derived. Mechanical Design and Manufacturing (7) (July 2008) 6. Chen, G., Jia, J.-Y.: Straight round elliptical flexure hinge of compound. Machine Design and Research 21(4), August 2
Surface Distresses Detection of Pavement Based on Digital Image Processing Aiguo Ouyang1, Chagen Luo1, and Chao Zhou2 1
Key Laboratory of Conveyance and Equipment, Ministry of Education, East China Jiaotong University, Nanchang, China 2 Jiangxi Agricultural University, Nanchang, China
Abstract. Pavement crack is the main form of early diseases of pavement. The use of digital photography to record pavement images and subsequent crack detection and classification has undergone continuous improvements over the past decade. Digital image processing has been applied to detect the pavement crack for its advantages of large amount of information and automatic detection. The applications of digital image processing in pavement crack detection, distresses classification and evaluation were reviewed in the paper. The key problems were analyzed, such as image enhancement, image segmentation and edge detection. The experiment results of the commonly used algorithms forcefully supported following conclusion: the noise in pavement crack images is effectively removed by median filtering, the histogram modification technique is a useable segmentation approach, the canny edge detection is an ideal identification approach of pavement distresses. Keywords: Digital Image processing, Crack detection, Edge detection, Image segmentation.
1 Introduction Maintenance of pavements is an important aspect for the Departments of Transportation all over the world. The first step towards maintenance is the identification of pavement distresses and their documentation for further action. Pavement distresses are visible imperfections on the surface of the pavements. Accurate evaluations will result in a better chance that resources will be distributed normally. Thus, yield a better service condition [1]. Pavement could be evaluated through the different types of distress experienced, such as cracking, disintegration and surface deformation. At present, there were various methods for conducting distress surveys, recording and analysing distress survey data [2]. Pavement engineers had long recognized the importance of distress information in quantifying the quality of pavements. Traditionally, pavement condition data are gathered by human inspectors who walk or drive along the road to assess the distresses and subsequently produce report sheets, but it is high cost and time consuming. Worse still, work has to be done along fast moving traffic. Such condition would endanger the safety of the personnel involved. Finally, large differences will D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 368–375, 2011. © IFIP International Federation for Information Processing 2011
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exist between the actual condition and evaluation results because of the subjectivity of the evaluation process. In the wake of tedious manual measurements and safety issues, a variety of types of methods have been devised to identify the cracks on pavements apart from the crude process of manual inspection. Image processing, ultrasonic detection and infrared detection, the most widely reported of the automated methods is that known as WiseCrax. Wisecrax [3] is an example of a commercially available device that uses infrared imaging to detect cracks on pavements. A camera is mounted on a vehicle with that takes pictures of the pavements continuously. Images are processed off-line overnight at the office workstation by a unique open architecture process using advanced image recognition software. Typical survey vehicle configuration consists of one or more downward-facing video cameras, at least one forward facing camera for perspective, and any number of additional cameras for the capture of right-of-way, shoulder, signage, and other information depending on agency requirements (as shown in Figure 1). New methods are being devised to identify cracks more efficiently and get closer towards perfection as good as the human eye and are still in the process. Ye et al. [4] presented a crack width detection method to extract the crack image of pavement distresses and calculate the crack width. Li et al. [5] proposed a pavement crack image analysis approach based on the image dodging to improve the reliability of the pavement crack recognition. Existing automatic real-time detection systems focus on the low identification rate and classification difficulty [6]. First, a lot of noise brings in pavement images caused by the road environment itself. Second, it is lack of easy and effective identification and classification algorithm [7]. Although some auto-inspection Survey Vehicle In-Office
Data Acquisition By Image Sensor
Stotrage Devices
Image Interpretation
Output devices
Supplemental Devices
Digitizing Devices
In-office or On Board Computer
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Lengend:
Real-time Processing or On Board Computer Processing In-office Processing
Fig. 1. Elements of a pavement imaging system
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system is in application at present, the system with surface-scan camera has the problem of low distinguish, and the dynamic collecting image clarity is not very ideal [8]. No method has achieved completely satisfactory results [9].
2 Significance of Pavement Distress Information Pavement distresses are visible imperfections on the surface of pavements. They are symptoms of the deterioration of pavement structures. Agencies that have implemented a Pavement Management System (PMS) collect periodic surface distress in formation on their pavements through distress surveys [10]. Distress information takes a vital role in quantifying the quality of pavements. This information has been used to document present pavement condition, chart past performance history and predict future pavement performance [11]. Pavement distress information is also broadly used as the only quality measure of pavements in many PMS. This is particularly true for systems used by local governments and in urban areas where roughness measurements are not performed because of a lack of equipment availability, high cost or a lack of relative applicability.
3 Pavement Image Analysis The purpose of image processing is to extract the distress features from the pavement image. Preprocessing is done by removing extraneous features that have higher pixel intensities than the mean pixel intensity in the image. In this process, all the pixels representing paint striping and surface textures brighter than the average background gray level are surpassed to the background. The effect of pavement image processing is illustrated by the following example. This study utilised full programming language software MATLAB 7.10.0 (Mathwork, Natick, MA, USA) to enable a series of MATLAB statements to be written into a file and then execute them with a single command. 3.1 Image Enhancement Image enhancement is applied in an attempt to remove noise in pavement images. Noise reduction is one aspect of preprocessing phase of crack detection process. Filtering is the most common form of noise reduction. Median filtering is one of the most commonly used preprocessing techniques for crack detection today. Median filtering is therefore applied as pavement image enhancement technique as suggested by Jitprasithsiri [12]. The median is much less sensitive than the mean to extreme values. Median filtering is better able to remove these outliers without reducing the sharpness of the image. Such a property of median filtering was explained by a classic example of salt and pepper noise which was a random addition of black and white pixels into a gray scale image. The result of median filtering in figure 6 indicated that noise was removed aptly by the median filtering compared with other operators.
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Fig. 2. Original pavement grayscale image
Fig. 3. Grayscale image with salt and pepper
Fig. 4. Laplacian operator
Fig. 5. Gaussian operator
Fig. 6. Result of median filtering
Fig. 7. Log operator
Fig. 8. Sobel operator
Fig. 9. Prewitt operator
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3.2 Image Segmentation Image segmentation is the crucial step in automatic image distress detection and classification (e.g., types and severities) and has important applications for automatic crack sealing [13]. The segmentation approach chosen was based on a histogram modification technique. This histogram modification was achieved through iterative clipping. At each stage in iterative clipping, more pixels were assigned to the background. This process continues until only distress features were left. The end result as shown in Figure 12 was an image in which the distresses were distinct and easily separable from the background. At this point, a threshold value could be determined automatically in order to isolate the distress features from the background. Transformation function in Figure 11 presented that the threshold value was near 0.6.
1400 1200 1000 800 600 400 200 0 0
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Output intensity value
1 0.8 0.6 0.4 0.2 0 0
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Fig. 11. Transformation function
1
Fig. 12. Result of histogram modification
3.3 Canny Edge Detection The Canny edge detector is a good edge detector among traditional edge detection algorithms [14]. The gray scale pavement image was first smoothed using a Gaussian
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filter with a specified standard deviation to reduce noise (see figure 13), then gradients were calculated to determine edge points. Using two threshold values 0.5 and 0.4, different correlated edge points were linked together. The strength of the method is its ability to detect edges in the presence of noise and to detect weak edges. Preliminary results from canny edge detection in figure 14~16 showed that the optimum identification of distress was dependent on the parameters used in the algorithm and that the optimum parameters varied with each image. There was a problem of coming up with false distress boundaries when a very high standard deviation in Gaussian filtering was used. The distress may seem wider than it actually was resulting in false severity level detection.
Fig. 13. Grayscale image by gaussian filtering
Fig. 14. Threshold value=0.5
Fig. 15. Threshold value=0.4
Fig. 16. Result of canny edge detection
3.4 Pavement Distress Classification and Evaluation Many protocols and definitions exist for pavement distresses classification and evaluation. One of the most widely used protocols is Strategic Highway Research Program Long-Term Pavement Performance (SHRP-LTPP) protocol [15]. SHRP-LTPP first classifies the type of cracks according to their orientations, locations, and shapes and quantifies the severity and extent of the cracks according to their properties, such as width, length, and areas. Another important protocol is the World Bank’s universal cracking indicator (UCI) [16]. UCI defined a single number to indicate the severity of all the cracks in a pavement segment. For a single crack such as a longitudinal, transverse, or diagonal crack, its indicator was defined as the product of
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its width and length. For the block and alligator cracks, their indicators were defined by the area that contains the block or alligator cracks. The unified crack index (ASTM STP 1121) is a protocol similar to UCI. The standard crack density can be automatically determined by dividing the number of pixels for the cracks by the number of the total pixels of the pavement segment.
4 Conclusions and Perspectives As mentioned above, digital images lend themselves to automated analysis because of the ability to analyze variations in grayscale as those variations relate to pavement features. A major force behind the move toward digital imaging of pavements is the opportunity to reduce distress data from those images through automated methods. With the fast development of analog videotaping, using digital imaging to capture pavement surface is becoming the preferred method. With advances in image sensors and computer technologies, the automation of data collection and analysis is a major goal of contemporary pavement management. Several automated analysis algorithms for pavement distress are in use and others are under development.
Acknowledgements The authors gratefully acknowledge the financial support provided by National Science and Technology Support Program (2008BAD96B04), Key Laboratory of Ministry of Education for Conveyance and Equipment, East China Jiaotong University (Grant No. 09JD10).
References 1. Kim, J.: Development of a Low-Cost Video ImagingSystem for Pavement Evaluation. Oregon State University. Ph.D. Thesis (1998) 2. Cheng, H.D., Miyojim, M.: Automatic pavementdistress detection system. Journal of Information Sciences 108, 219–240 (1998) 3. T.R.B.E. NCHRP synthesis 334: Automated Pavement Distress Collection Techniques. Transportation Research Board of the National Academies, Washington, D.C. (2004) 4. Ye, G.R., Zhou, Q.S., Lin, X.W.: Measurement of Surface Crack Width Based on Digital Image Processing. Journal of Highway and Transportation Research and Development 27, 75–78 (2010) (in Chinese) 5. Li, Q.Q., Hu, Q.W.: A Pavement Crack Image Analysis Approach Based on Automatic Image Dodging 27, 1–5 (2010) (in Chinese) 6. Wang, R.B., Wang, C., Chu, X.M.: Developments of Research on Road Pavement Surface Distress Image Recognition. Journal of Jilin University (Engineering and Technology Edition) 32, 91–97 (2002) (in Chinese) 7. Zhang, J.: Study on Pavement Crack Identification and Evaluation Technology Based on digital Image Processing. Chang’an University. Ph.D. Thesis (2004) (in Chinese)
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8. Chu, X.M., Yan, X.P.: The Automatic Search of Pavement Surface Distress Image Based on on-line Learning. In: International Conference on Transportation Engineering 2007 (ICTE 2007), vol. 246, pp. 3282–3287 (2007) 9. Tsail, Y.C., Kaul, V., Russell, M.M.: Critical Assessment of Pavement Distress Segmentation Methods. Journal of Transportation Engineering 136, 11–19 (2010) 10. Haas, R., Hudson, W.R., Zaniewski, J.: Modem Pavement Management. Krieger Publishing Company, Malabar (1994) 11. Shahin, M.Y.: Pavement Management for Airport, Roads and Parking Lots. Chapman & Hall, New York (1994) 12. Jitprasithsiri: Development of a New Digital Pavement Image Processing Algorithm for Unified Crack Index Computation. University of Utah. Ph.D. Thesis (1997) 13. Mustaffara, M., Lingb, T.C., Puanb, O.C.: Automated Pavement Imaging Grogram (APIP) for Pavement Cracks Classification and Quantification-A Photogrammetric Approach. The International Archives of the Photogrammetry. Remote Sensing and Spatial Information Sciences 37, 362–372 (2008) 14. Canny, J.: A computational approach to edge detection. IEEE Transactions on Pattern Analysis and Machine Intelligence 8, 679–698 (1986) 15. Hawks, N.F., Teng, T.P., Bellinger, W.Y., Rogers, R.B., Baker, C., Brosseau, K.L., Humphrey, L.C.: Distress Identification Manual for the Long-Term Pavement Performance Project, SHRP-P-338. National Research Council, Washington, D.C. (1993) 16. Paterson, W.D.: Proposal of Universal Cracking Indicator for Pavements. Transportation Research Record 1455, TRB, National Research Council, Washington, D.C., pp.69–76 (1994)
The Application Research of Neural Network in Embedded Intelligent Detection Xiaodong Liu1, Dongzhou Ning1, Hubin Deng2, and Jinhua Wang1 1
Compute Center of Nanchang University, 330039, Nanchang, Jiangxi, China [email protected] 2 East China Jiaotong University, 330039, Nanchang, Jiangxi, China [email protected]
Abstract. Neural network which can adapt the sample data by training has good fault-tolerance and can be used in the field of intelligence widely. In the embedded system, restricted to the resources and the capacity of processor, the neural network application has a series of problems, such as losing timelines and the system could be collapsed easily. This article discusses how to use limited memory, processor and external equipment resources to achieve the neural network algorithm for improving the universality of detection system and adaptive ability in the embedded intelligent measuring system. Keywords: Neural Network, Embedded System, Intelligent Detection.
1 Introduction Most embedded detective devices are developed by using the fixed parameter method, that is, the mapping relationship between test data and test conclusion is fixed. However, in practical application, the input conditions of detection and the testing standards may need to be changed, which may make the existing detection system inadaptable. The neural network owns the ability of self-adaptation and self-learning, therefore, by studying on the sample data, it can determine the mapping relationship between the input and the output. And if the neural network is applied to the detection system, it may adjust the mapping relationship automatically by training samples, which can make the detection system more flexible and adaptable. Application of the algorithm is shown in the figure 1 [1].
Detection data acquisition
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Fig. 1. Application of neural network D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 376–381, 2011. © IFIP International Federation for Information Processing 2011
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Because of the constraints of the resources of embedded portable device and the capacity of processor, computational complexity should be minimized in the application of neural network algorithm, thus to improve the efficiency by centralizing resources to deal with necessary tasks.
2 Neural Network Platform Design Great success has already been achieved in the research and application of neural network, however, there is no perfect theory as a guide in the aspect of network structure development and design, so network parameters are adjusted just only on the basis of former researchers’ designing experience and experiment analyses. The functions of neural network platform development are network parameter settings, network training, network training analysis, network testing, network prediction etc. In the network structure designing and the training algorithm, because of the resources constraints in embedded system, we should use as simple and effective methods as possible. The following is the description of issues needed to be considered in the design: 2.1 The Choice of Network Model 2-layer linear perceptron model and 3-layer BP network model are provided and the user can choose one of them in the network parameter settings in accordance with the complexity of the detection system. According to the Almighty Approaching Theorem, a 3-layer BP neural network with a hidden layer can approximate to any continuous function of bounded domain with arbitrary precision as long as there are enough hidden layer nodes[2]. Therefore in terms of the function, 3-layer BP neural network can meet most sophisticated detection systems’ requirements, while for some detection systems which are simple mapping, linear perceptron model with a small amount of calculation and fast speed can be chosen so as to maximize the efficiency of the systems. 2.2 The Choice of the Number of Input and Output Nodes The number of the input nodes is determined by testing item. The number of the output nodes is generally determined by the number of the testing conclusions. But if there are a lot of testing conclusions, the number of the output nodes could become great, then, the amount of calculation also increases. So when there are a lot of testing conclusions, the testing conclusions can be encoded to binary code, then output nodes take the number greater than or equal to log2N, where N is the number of conclusions. 2.3 The Choice of the Number of Hidden Layer Nodes If the network model is BP network, the number of the hidden layer nodes needs to be set. Generally speaking, if there are too few hidden layer nodes, the network can not study well, and much more training will be needed and, meantime the training will not be highly precise; while too many nodes will bring issues such as a large amount of calculation, long training time and reduced network fault-tolerance capacity. Because there is no corresponding theoretical guidance, most designs are determined by
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combining the experience and trial calculation. System uses the default settings as the empirical formula (1).
n1 = n + m + 2 .
(1)
In the formula (1), “n1” is the number of the hidden layer nodes; “n” is the number of the input nodes; “m” is the number of the output nodes. If the training effect of experience value is not good, you can re-set the number of the hidden layer nodes in the parameter settings and do many experiments in order to achieve faster convergence rate. In order to know the training efficiency, you should output the training number in training process, changes of the network errors, changes of network weights and the training time and so on, so as to a make a report for the network analyses. 2.4 The Choice of Transfer Function In the application of detection, most of the outputs are the field data and test conclusions. The field data are collected by the acquisition system; detection conclusions are obtained from the neural network algorithm. The detection conclusions are indicated with two-value, so the transfer function of output layer generally uses the sigmoid function or the hard limit function. The sigmoid function formula is shown as following.
f ( x ) =
1 1 +
e
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.
(2)
2.5 The Choice of Initial Weight Initial weight is generated randomly by the random function, and its value range is (-0.5, 0.5).
2.6 The Choice of the Learning Rules Because of the particularity of embedded systems, we should try to select the learning algorithm with simple calculation and low memory consumption. The perceptron network model structure is simple, and the overall amount of calculation is not large, so the weight correction algorithm of BP model is mainly considered. Conventional BP learning algorithm has large amount of calculation and long training time, and the slope of sigmoid function is close to 0 when the input is large, therefore the increase amplitude of gradient of learning algorithm is very small ,which may make the modification process of network weights almost at a standstill and the training very inefficient. To reduce the amount of calculation and to improve the efficiency, we may adopt a flexible BP learning algorithm. We only need to consider the symbol of gradient to the error function, rather than the increase amplitude of gradient. The symbol of gradient determines the direction of weight updating, and the weight size change is determined
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by an independent “update value” (based on the former “update value”)[2].The iterative process of weight correction example is shown below:
ω ( t + 1) = ω ( t ) + αΔω ( t ) × sgn(
∂E t ). ∂ω ( t )
(3)
In the formula (3)[2], Δω (t) is the previous update value, and the initial value Δω (0) is set by the actual application. α is the learning parameter, using variable step-size learning, that is, if it is in two successive iterations, the symbol of the partial derivative of error function to a weight remains unchangeable, then α is 1.2; otherwise α is 0.8[2]. It is faster to converge by using this algorithm, which can also be achieved effectively in embedded system.
2.7 The Preprocessing of Input and Output Data in Training Sample In the network learning process, because the transfer function of neuron is a bounded function, while in the detection, as the dimension and unit of input test item data may be different, some values are very large, while some values are very small, which has a great influence on the network.. To prevent some neurons from reaching saturation state, and meantime make the larger input fall in the region where gradient of neuron activation function is large, input and output vectors need to be normalized before the training. Namely:
x' i =
xi - xi min . xi max - xi min
(4)
In the formula (3): ximax, ximin are the maximum value and minimum value of each input component of number i neuron; xi, x'i are respectively the former and later input component after pretreatment of number i neuron. The input data values after normalization processing range between 0 and 1. Normalization processing requires a large number of mathematical operations. But if there is no huge difference among the input data values, the normalization is not required to reduce the computational complexity. Therefore, we may use whether to normalize the input data or not as the network training option parameter and make choice before the training. If the neural network training is unsuccessful, or if the training time is too long, we need to analyze the process of training and to train after readjusting the network parameters. If the training results are satisfactory, we may use the testing sample data to test the function of the network.. Successful testing demonstrates that the construction of the network is completed, and then the network parameters and the weights of each Layer of the network are saved as files, ready for testing procedures.
3 Input and Output Platform Design In the application of neural network, we need to input a large number of training data and output the training process and the training results, which requires a higher demand of input and output. To reduce the cost of portable detect device and the burden of
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volume, we may use two kinds of solution methods. One method is training on a host computer independently, and we download the network weights and network parameters of success training to the target computer in form of files for the detection program to recover the network; The other method is sharing the rich resources of input and output device of remote computer by using the remote training mode. In the above two methods, the training process of the former method is conducted on PC machine, which doesn’t take up resources of embedded device, and its advantage is that the high-speed PC-CPU and the large capacity memory can greatly enhance the training speed, while the disadvantage is that the neural network parameter settings and the training are independent of detection system, which is inconvenient for users to modify and update the system; the second method integrates network training and testing, completed by the target machine, with remote computer only serving as sharing input and output devices. Because of limitations of embedded CPU and memory, the training becomes slow, and even collapses when the network structure is complex, or the amount of calculation is huge. But the system is flexible, and more convenient to be maintained and updated. Because in neural network design, requirements of application have already been considered, and we have adopted more effective and simpler methods in the design of network structure and training algorithm; besides, the network training is the preliminary work of establishing detection system, and it will not be run after the network is built successfully, so its speed does not affect the work efficiency of the detection system. For these reasons, we use the second method to design. To reduce the development, maintenance and use costs, we use B / S structure in the system, embedding a small WEB server in device, all of the user interface using static or dynamic web pages and being viewed through remote browser, and the data interaction and generation of dynamic web pages being realized by using high efficient CGI programming. The overall structure of the system is shown in figure 2: ,QWHUQHW,QWUDQHW EURZVHU 1HWZRUN HTXLSPHQW 7&3,3 6LJQDO DFTXLVLWLRQ
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4 Conclusion In the detection system, using neural network algorithms can increase the system flexibility and self-adaptability. When testing standards or project data change, we can use new training data to train the network again and get the new network parameters for updating system rapidly. Besides, the system is based on remote detection technology, making the system updating more convenient. And that also reduces the requirements
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of input and output of portable detect device and the cost of hardware and software development; if the test site environment is poor, the remote detection could show more on its advantages. But the small embedded WEB server in the system may accordingly occupy more resources .Moreover, due to the inherent delay of network communication, the display of testing data and testing results have a certain delay relative to field data, so it is only suitable to the situation in which on-site environmental data are stable. If the on-site environment changes fast, you can add display components in the embedded device, which can have the devices test offline, and neural networks building and the system maintaining and updating could be conducted remotely.
References
应信号处理 经网络技术
1. Bernard, W., Samuel, D.S.: Adaptive Signal Processing( 自适 ). Machinery Industry Press, Beijing (2008) 2. Tian, Y.: Hybrid Neural Network Technology(混合神 ). Science Press, Beijing (2009)
The Theoretical Analysis of Test Result’s Errors for the Roller Type Automobile Brake Tester Jun Li, Xiaojing Zha, and Dongsheng Wu School of Mechanical and Electronic Engineering, East China Jiaotong University, Nanchang 330013, P.R. China
Abstract. The main testing parameter of the roller brake tester is the braking force. Actually, there are some differences in results even if the same vehicle is tested on the same tester. So it will bring trouble to evaluate the braking performance accurately. Based on force analysis, the mathematical model of the roller opposite force type automobile brake tester is built in this article. And then the factors of influencing braking force value will be analyzed by theoretical calculations Taking the instance of the Jianghuai light truck and using the mathematical model analyze influencing factors for testing results and calculate error value. The results showed that adhesion cofficients of between testing wheels and rollers and between non-testing wheels and floor, structure of the roller brake testor have an influece on testing results of braking force and structure of the roller brake testor is the least. The theoretical analysis provide references for comparison test among testing equipments of the braking performance. Keywords: Roller brake tester, Mathematical model, Adhesion coefficient, Braking force, Error.
1 Introduction Automobile braking performance is one of the most important factors in vehicle safety performances[1][2]. It is also a key indicator and an essential inspection item of vehicle safety performance test. Currently, the automobile braking performance is tested mostly through the roller opposite force type brake tester according to GB7258-2004 named “Safety specifications for power-driven vehicles operating on roads” However, the same car in different tester for the braking performance test, the results often not consistent, even contrary. So that, it can't evaluate the vehicle's braking performance whether reached the national standards. Based on the above situation, it is necessary to approach the influencing factors of testing results for the parameters of the testers, and establish its mathematical model of automobile testing on the roller brake tester. Thus, it can analyze the relationship of the vehicle testing results from different testers, and it can obtained more consistent evaluations of the vehicle's braking performance. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 382–389, 2011. © IFIP International Federation for Information Processing 2011
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2 Mathematical Model of Automobile Testing on the Roller Brake Tester According to the braking test of automobile on the roller tester, the force analysis is processed in two ways: force analysis of front wheels test and rears wheel test. So the mathematics theoretical models are built individually. When analyzing, it is assumed that the center of front and rear wheels is located in the same level. And the influences caused by rolling resistance and resilient wheels on force-measuring system are ignored. 2.1 Mathematical Model of Front Wheels Braking Test [3] When the automobile’s front wheels brake, the force analysis of the roller brake tester is as shown in Figure 1.
D----wheel diameter(mm); d----roller diameter(mm); α----formed angle; G1, G2----load of the front wheels and rear wheels(N);
、N ----normal force of the front and rear rollers to front wheels(N); 、F ----tangential force of the front and rear rollers to front wheels(N);
N1 Fb1
2
b2
φ1----adhesion coefficient between testing wheels and rollers;
φ2----adhesion coefficient between non-testing wheels and floor; Xb2----horizontal reaction force of floor to rear wheels(N) Fig. 1. The force analysis of front wheels braking test on the roller tester
According to the principle of mechanical equilibrium, relations can be built as below:
∑ FX = 0 Fb1 cos α + Fb 2 cos α + N1 sin α − N 2 sin α − F0 = 0
(1)
∑ FY = 0 − Fb1 sin α + Fb 2 sin α + N1 cos α + N 2 cos α − G1 = 0
(2)
With the increasing of Fb1 when the front wheels brake force is being tested, if the front wheels don’t slip backwards, the maximum value of Fb1 and Fb2 will be:
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Fb1max = N1 ⋅ ϕ1 and Fb 2 max = N 2 ⋅ ϕ1 . Meanwhile, F0 = X b 2max = G2 ⋅ ϕ 2 . So Eq.1 and Eq.2 can be written as:
N1 =
G2ϕ2 (ϕ1 sin α + cos α ) − G1 (ϕ1 cos α − sin α ) (1 + ϕ12 ) sin 2α
(3)
N2 =
G2ϕ2 (ϕ1 sin α − cos α ) + G1 (ϕ1 cos α + sin α ) (1 + ϕ12 ) sin 2α
(4)
Under the premise of no moving backwards, the vehicle’s front wheels maximum brake force should be:
Fbf max = Fb1max + Fb 2 max = ( N1 + N 2 )ϕ1 = According to Eq.3, if ϕ2 =
G2ϕ12ϕ 2 + G1ϕ1 (1 + ϕ12 ) cos α
(5)
G1 (ϕ1 cos α − sin α ) then N1 = 0 , the tested wheels G2 (ϕ1 sin α + cos α )
will leave the roller and move backwards. Meanwhile we can get:
N2 =
G1 ϕ1 sin α + cos α
(6)
If the tested wheels are locked after leaving the roller tester, the maximum brake force of the front wheels is:
Fbf′ max = N 2 ⋅ ϕ1 =
G1ϕ1 ϕ1 sin α + cos α
(7)
2.2 Mathematical Model of Rear Wheel Braking Test When the vehicle’s rear wheels brake force is tested, the force analysis of the roller brake tester is as shown in Fig.2.
Fig. 2. The force analysis of rear wheel braking test on the roller brake tester
The Theoretical Analysis of Test Result’s Errors
385
Similarly, according to the principle of mechanical equilibrium, relations can be built as below:
∑ FX = 0 N1 sin α + Fb1 cos α + Fb 2 cos α − F0 − N 2 sin α = 0
(8)
∑ FY = 0 N1 cos α + N 2 cos α + Fb 2 sin α − Fb1 sin α − G2 = 0
(9)
If the rear wheels don’t slip backwards, have Fb1 max = N1 ⋅ ϕ1 , Fb 2 max = N 2 ⋅ ϕ1 and F0 = X b max = G1 ⋅ ϕ 2 . So it can be gotten that:
N1 =
G1ϕ2 (ϕ1 sin α + cos α ) − G2 (ϕ1 cos α − sin α ) (1 + ϕ12 ) sin 2α
(10)
N2 =
G1ϕ 2 (ϕ1 sin α − cos α ) + G2 (ϕ1 cos α + sin α ) (1 + ϕ12 ) sin 2α
(11)
The maximum brake force of the rear wheels is
Fbr max =
G1ϕ12ϕ2 + G2ϕ1 (1 + ϕ12 ) cos α
According to Eq.10, it can be known that N1 = 0 when ϕ2 =
(12)
G2 (ϕ1 cos α − sin α ) , G1 (ϕ1 sin α + cos α )
then
N2 =
G2
ϕ1 sin α + cos α
(13)
If the tested wheels locked after leaving the roller tester, the maximum brake force of the rear wheels is:
Fbr′ max = N 2 ⋅ ϕ1 =
G2ϕ1 ϕ1 sin α + cos α
(14)
3 Analysis on Influencing Factors of Testing Results [4] [5] 3.1 The Adhesion Coefficient between Testing Wheels and Rollers According to GB/T13564-2005 “the roller opposite force type automobile brake tester”, if vehicle is lighter than 3 tons, the roller tester’s diameter should be 245 mm and the center distance should be 430 mm. Take a light truck HFC1061KS for example, its tires model type is 7.50-16, and the individual weight of front and rear axles are 1716 kg and 1412 kg. Considering the actual testing situation, let ϕ1 = 0.6 ~ 0.95 and ϕ 2 = 0.7 . Substituting them in Eq.5, the calculation results are shown in Fig.3 as below.
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J. Li, X. Zha, and D. Wu
4
1.6
x 10
The relationship between the value of φ1 and front and rear brake force
1.5
Fb(N)
1.4 1.3 1.2 front Fbf
1.1 1 0.6
rear F br
0.65
0.7
0.75 0.8 φ1
0.85
0.9
Fig. 3. The relation curves of the front and rear wheel braking forces with the increase of φ1
From Fig.3, it can obviously tell that the difference of braking force between ϕ1 = 0.6 and ϕ1 = 0.95 is up to about 4000 N, which reflects that the braking performance is affected by φ1. Because the rollers may be worn more or less after a long use, the value of φ1 will decrease. Regarding the front and rear brake force when ϕ1 = 0.75 as reference values, some comparisons are made as Tab.1 between
ϕ1 = 0.65 and ϕ1 = 0.75 . Table 1. The comparison of the front and rear brake force between ϕ1 = 0.65 and ϕ1 = 0.75
Front Fbf Rear Fbr
ϕ1 = 0.65
ϕ1 = 0.75
12324 N 11458 N
13488 N 12695 N
Relative error δ 8.63% 9.75%
It can be concluded that with the increase of adhesion coefficient between wheels and rollers, the braking force test capability of front and rear wheels will significantly increase as well. Hence, a good value of φ1 which must be ensured through a number of ways is a basic premise for braking force test. 3.2 The Adhesion Coefficient between Non-testing Wheels and Floor Similarly, taking the light truck and the same tester as an example, the front and rear braking force will be calculated. According to GB7258-2004, the value of φ1 should not be less than 0.75. So it is taken as 0.75 on the calculation. Considering the actual testing situation, φ2 is taken between 0.4 and 0.8. The results are calculated and shown in Fig.4.
The Theoretical Analysis of Test Result’s Errors
1.45
x 10
4
387
The relationship between the value of φ2 and front and rear brake force
1.4 1.35
b
F (N)
1.3 1.25 1.2 1.15 front F bf
1.1
rear F br
1.05 0.4
0.5
0.6
φ2
0.7
0.8
Fig. 4. The relation of the front and rear brake force with the increase of φ2
From Fig.4, we can tell that the test result differs when we take different values of the adhesion coefficient between non-testing wheels and floor. Furthermore there is a proportional relationship between the value of φ2 and braking force. The difference of braking forces between ϕ 2 = 0.4 and ϕ 2 = 0.8 is up to about 2000 N, which has a great impact on the evaluation of braking performance. In test stations, if the ground cannot be cleaned up or maintained in time, it will lead to the decrease of adhesion coefficient, and then affect the evaluation on braking performance. For example, the adhesion coefficient of terrazzo floor is less than 0.6. Regarding the front and rear brake force when ϕ 2 = 0.7 as reference values, some comparisons are given as Tab.2 between ϕ 2 = 0.7 and ϕ 2 = 0.6 . Table 2. The comparison of the front and rear brake force between ϕ 2 = 0.6 and ϕ 2 = 0.7
Front Fbf Rear Fbr
ϕ2 = 0.6
ϕ 2 = 0.7
12906 N 11988 N
13487 N 12694 N
Relative error δ 4.31% 5.56%
By the Eq.6, Eq.7, Eq.13 and Eq.14, it is known that when the φ2 takes a particular data ( N1 = 0 ) the testing braking force is minimum. It means the vehicle is slipping on the tester. That may be one reason why the vehicle with good brake performance cannot pass the test. So in the actual test, it is specified that the adhesion coefficient between non-test wheels and ground cannot be less than 0.7.
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3.3 Structural Factors of the Roller Brake Tester After investigation we found that the sizes of testers which are being used in different test institutions have differences, although GB/T13564-2005 has made provisions for the standard of tester. According to the force analysis in Fig.1 and Fig.2, it can be known that the formed angle α is related to the wheel diameter D, the roller diameter d and the roller center distance L. Supposing that D is a constant value (taking the light truck as an example), we can discuss the relationship between the formed angle α and braking force through combining with the actual parameters of different testers. The formed angle α is proportional to the front and rear braking force, as shown in Fig.5.
4
1.45
x 10
The relationship between the value of α and front and rear brake force
1.4
Fb(N)
1.35 1.3
1.25 1.2 29
front Fbf rear Fbr
30
31
32 Į
33
34
35
Fig. 5. The braking force of front and rear wheels with the change of the formed angle α
Also taking the light truck as an example, applying relevant parameters of three different testers and combining Eq.5 with Eq.12, the braking force of front and rear wheels are shown as below: Table 3. The front and rear brake force of JAC light truck on the different testers
Type
d(mm)
L(mm)
α(°)
Fbf(N)
Fbr(N)
1
200
390
29.6
13293.9
12512.7
2
240
470
34.5
14027.5
13203.2
3
245
430
31.0
13487.0
12694.4
In Tab.3 the data of Type 3 is the ruled data in GB/T13564-2005. If taking them as reference values, the relative errors are -1.43% in Type 1 and 4.01% in Type 2.
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389
From Fig.5 and Tab.3, the conclusion is made: when the same vehicle is tested in different testers, the formed angles are different due to the different structures. It causes the errors in test results. Therefore, the structure of the brake tester can be an impact for the braking force test as well.
4 Conclusions By taking a light truck as an example, the mathematical model is established through force analysis. Combining the specific parameters of tester, the test results of braking force can be theoretically analyzed and calculated by the model. The conclusions can be made as below: 1. The testing results are affected by the adhesion coefficient between the tested wheels and rollers, by the adhesion coefficient between non-tested wheels and ground, and by the structure of the brake roller tester. Among them, the structure of brake tester contributes relatively less affection to the braking force. 2. Due to the difference of the structure of testers in different places, it makes some differences in braking force test results. They belong to structural errors and are unavoidable in the testing process. From Tab.3 and Fig.5 we can see that the formed angle has less influence in test results. It indicates that doing comparative tests of different test devices is feasible and the test results are comparable. 3. To reduce the test errors resulting from the structure of the testing equipment, the formed angles α can be modified through the mathematical model if they are too large or too small.
Acknowledgement The work is supported by the Department of Transportation of Jiangxi Province (2009T0053).
References 1. Zhou, D., Tao, S., Li, W.: The Establishing and Analysis of Stress Model about the Roller Brake Tester and the Flat Brake Tester. Machinery Design & Manufacture (1), 50–52 (2005) 2. Lan, Y., Hao, D.: The analysis of advantage and disadvantage between the roller brake tester and the platform brake tester. Highways & Transportation in Inner Mongolia (3), 28–30 (1998) 3. Jiao, G., Kong, X., Liu, G.: Contrastive Analysis of Static Inspection and Dynamic Inspection of Automobile Brake Performance. Journal of Northeast Forestry University 34(5), 93–94 (2006) 4. Yu, Z.: Automobile Theory. China Machine Press, Beijing (2006) 5. Huang, X.: Analyze the Key Factors that Influence the Braking Force Test. Northeast Forestry University, Ha Erbin (2006)
A Type of Arithmetic Labels about Circulating Ring Ergen Liu, Dan Wu, and Kewen Cai School of Basic Sciences, East China Jiaotong University, Nanchang, P.R. China, 330013 [email protected]
Abstract. The graph composed with several rings is a kind of important and interesting graph, many scholars studied on the gracefulness of this kind of the graph, The reference [1] is given the gracefulness of
m
kinds
C 4 with one
common point. In this paper, we researched the arithmetic labels of four kinds graph:
C8,1,n , C8, 2, n , C8,3,n , C8, 4,n , and we proved they are all
(d ,2d ) --arithmetic graph. Keywords: Arithmetic graph, labeling of graph, C 8,i ,n .
1 Introduction The graph in this paper discussed are undirected, no multiple edges and simple graph, the unorganized state of definitions and terminology and the symbols in this graph referred to reference[2][3]. There are two kinds of labels of the graph: one is the reduced label, is to say that in order to get the label of one edge you should reduce the endpoints of the edge; the other is additive label, for the same you should acttive the endpoints of one edge to get the label of the edge. For example, the well-known of “Gracefulness” is reduced. the “Compatible labels” is additive. In 1990, B.D.Achaya and S.M.Hegde import the concept of “Arithmetic lables”(referred to reference[2]), which is a more extensive additive label, it have applied value on solution to question of the joint ventures in rights and obligations. Definition 1.1. For G = (V , E ) , if there is a mapping f ( called the vertices label ) from V (G ) to the set of nonnegative integer N 0 , meet:
(1) f (u ) ≠ f (v)
,which u ≠ v ,and u,v ∈ V (G) ;
, , ,k + (q − 1)d }.
( 2) {f (u ) + f (v) uv ∈ E (G )} = {k k + d
,
Then we call graph G is a ( k d ) --arithmetic graph. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 390–397, 2011. © IFIP International Federation for Information Processing 2011
v of the
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2 Main Results and Certification Theorem 2.1. C8,1,n is a ( d ,2d ) --arithmetic graph. Proof. As the graph shown on fig.1. v2(0)
v2(1)
v6(0)
v4(0)
v4(1)
v(2n−1)
v6(1)
v1(0) v1(1) v3(0)
v7(0)
v5(0)
v1(2) v3(1)
v1(n) v(3n−1)
Fig. 1. The Graf
v(6n−1)
v1( n−1)
v7(1)
v5(1)
v(4n−1)
v(7n−1)
v(5n−1)
C8,1,n
Label all vertices as follows:
f (v1(i ) ) = 8id (i = 0,1,2,
, n) ,
f (v 2( i ) ) = 8id + d (i = 0,1,2,
, n − 1) ,
f (v 3(i ) ) = 8id + 3d (i = 0,1,2,
, n − 1) ,
f (v 4( i ) ) = 8id + 6d (i = 0,1,2,
, n − 1) ,
f (v 5(i ) ) = 8id + 2d (i = 0,1,2,
, n − 1) ,
f (v 6( i ) ) = 8id + 5d (i = 0,1,2,
, n − 1) ,
f (v 7(i ) ) = 8id + 7d (i = 0,1,2,
, n − 1) .
Now we proof that the mapping We can see the mapping
{
f is arithmetic labeling of C8,1,n .
f meet f (u ) ≠ f (v) which u ≠ v and u, v ∈ V (C8,1,n ) .
Next we prove f (u ) + f (v ) uv ∈ E (C8,1, n )} is an arithmetic progression in the way of mathematical induction. When n = 1 Then f (v1( 0 ) ) = 0 , f (v 2( 0) ) = d , f (v 3( 0) ) = 3d , f (v 4( 0) ) = 6d , f (v 5( 0) ) = 2d ,
f (v 6( 0) ) = 5d , f (v 7( 0) ) = 7 d , f (v1(1) ) = 8d .
{
Therefore f (u ) + f (v) uv ∈ E (C8,1,1 )}
{
= f (v1( 0 ) ) + f (v 2( 0) ), f (v1( 0) ) + f (v3( 0 ) ), f (v3(0) ) + f (v5( 0) ),
f (v 2(0 ) ) + f (v 4( 0) ), f (v5( 0) ) + f (v7( 0) ), f (v 4(0 ) ) + f (v6( 0) ), f (v 6( 0) ) + f (v1(1) ), f (v 7( 0) ) + f (v1(1) )}
,,,,, , ,
= {d 3d 5d 7d 9d 11d 13d 15d } is an arithmetic progression, and the common difference is 2 d .
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E. Liu, D. Wu, and K. Cai
Suppose when n = k − 1 , we know
{f (u) + f (v) uv ∈ E (C
} = {d , d + 1 × 2d , d + 2 × 2d ,
, d + (8k − 9) × 2d }
8,1, k −1 )
is an arithmetic progression, and the common difference is 2 d . Then when n = k
{f (u) + f (v) uv ∈ E (C = {f (u ) + f (v) uv ∈ E (C
8,1, k
)}
} ∪ {f (v1( k −1) ) +
8,1, k −1 )
f (v 2( k −1) ), f (v1( k −1) ) + f (v3( k −1) ),
( k −1) ( k −1) f (v3( k −1) ) + f (v5( k −1) ), f (v 2 ) + f (v 4 ), f (v5( k −1) ) + f (v7( k −1) ), ( k −1) (k ) f (v 4( k −1) ) + f (v6( k −1) ), f (v6( k −1) ) + f (v1( k ) ), f (v 7 ) + f (v1 )}
= {d , d + 1 × 2d , d + 2 × 2d ,
, d + (8k − 9) × 2d } ∪ {d + (8k − 8) × 2d ,
d + (8k − 7) × 2d , d + (8k − 6) × 2d , d + (8k − 5) × 2d , d + (8k − 4) × 2d , d + (8k − 3) × 2d , d + (8k − 2) × 2d , d + (8k − 1) × 2d }
,
,
= {d d + 1 × 2d d + 2 × 2d
, ,d + (8k − 1) × 2d}
is an arithmetic progression, and the common difference is 2d . In sum for the arbitrary n ∈ N 0 , the mapping f : V (C 8,1,n ) → N 0 meet: (1) f (u ) ≠ f (v) when
{
u ≠ v and u, v ∈ V (C8,1,n ) ;
,
,
, ,d + (8n − 1) × 2d}.
(2) f (u ) + f (v) uv ∈ E (C8,1,n )} = {d d + 1 × 2d d + 2 × 2d Therefore C8,1, n is a ( d ,2d ) --arithmetic graph. Theorem 2.2. C8, 2,n is a ( d ,2d ) --arithmetic graph.
Proof. As the graph shown on fig.2. v 3( 0 )
v 5( 0)
v 3(1)
v1( 0)
v1(1 )
v2( 0)
v2(1 ) v4( 0 )
v 6( 0)
v (3n−1)
v 5(1)
v (2n−1)
v2( 2)
v (4n−1)
v 6(1)
Fig. 2. The Graf
v1( n )
v1( n−1)
v1( 2)
v4(1)
v (5n−1)
C 8, 2 , n
v2( n ) v (6n−1)
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393
Label all vertices as follows:
f (v1(i ) ) = 7id (i = 0,1,2, f
(v 2(i ) )
, n) ,
= 7id + d (i = 0,1,2,
, n) ,
f (v3(i ) ) = 7id + 3d (i = 0,1,2,
f (v 4(i ) ) = 7id + 6d (i = 0,1,2,
, n − 1) ,
= 7id + 2d (i = 0,1,2,
, n − 1) ,
f
, n − 1) ,
(v5(i ) )
f (v 6(i ) ) = 7id + 5d (i = 0,1,2,
, n − 1) .
Now we proof that the mapping f is arithmetic labeling of C8, 2 ,n We
can
see
u , v ∈ V (C 8 , 2 , n ) .
the
mapping
f
meet
f (u ) ≠ f (v) which u ≠ v and
{
Next we prove f (u ) + f (v) uv ∈ E (C8, 2, n )} is an arithmetic progression in the
way of mathematical induction. When n = 1 Then f (v1( 0) ) = 0 , f (v 2( 0 ) ) = d , f (v3( 0) ) = 3d , f (v 4( 0 ) ) = 6d , f (v 5( 0 ) ) = 2d ,
f (v 6( 0) ) = 5d , f (v1(1) ) = 7 d , f (v 2(1) ) = 8d .
{
Therefore f (u ) + f (v) uv ∈ E (C8, 2,1 )}
{
= f (v1( 0) ) + f (v 2( 0) ), f (v1(0) ) + f (v3( 0) ), f (v3(0 ) ) + f (v5( 0 ) ),
f
(v 2(0 ) )
+ f (v 4( 0) ), f (v5( 0) ) + f (v1(1) ), f (v 4(0 ) ) + f (v6( 0) ), f (v 6( 0) ) + f (v 2(1) ),
f (v1(1) ) + f (v 2(1) )}
,,,,, , ,
= {d 3d 5d 7 d 9d 11d 13d 15d }
is an arithmetic progression, and the common difference is 2d . Suppose when n = k − 1 , we know
{f (u) + f (v) uv ∈ E (C
} ={d , d + 1 × 2d , d + 2 × 2d ,
8, 2 ,k −1 )
, d + (7k − 7) × 2d }
is an arithmetic progression, and the common difference is 2d . Then when n = k
{f (u) + f (v) uv ∈ E (C = {f (u ) + f (v) uv ∈ E (C
8, 2 , k
)}
} ∪ { f (v1( k −1) ) +
8, 2 , k −1 )
f (v3( k −1) ),
f (v3( k −1) ) + f (v5( k −1) ), f (v 2( k −1) ) + f (v 4( k −1) ), f (v5( k −1) ) + f (v1( k ) ), f (v 4( k −1) ) + f (v 6( k −1) ), f (v 6( k −1) ) + f (v 2( k ) ), f (v1( k ) ) + f (v 2( k ) )}
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E. Liu, D. Wu, and K. Cai
d + (7k − 7) × 2d } ∪ {d + (7k − 6) × 2d ,
= {d , d + 1 × 2d , d + 2 × 2d ,
d + (7 k − 5) × 2d , d + (7k − 4) × 2d , d + (7k − 3) × 2d , d + (7k − 2) × 2d , d + (7 k − 1) × 2d , d + 7 k × 2d }
,
,
= {d d + 1 × 2d d + 2 × 2d
, ,d + 7k × 2d }
is an arithmetic progression, and the common difference is 2d . In sum for the arbitrary n ∈ N 0 , the mapping f : V (C8, 2,n ) → N 0 meet: (1) f (u ) ≠ f (v) when u ≠ v and u, v ∈ V (C8, 2 ,n ) ;
,
{
,
(2) f (u ) + f (v) uv ∈ E (C 8,2,n )} = {d d + 1 × 2d d + 2 × 2d
, ,d + 7n × 2d } .
Therefore C8, 2,n is a (d ,2d ) --arithmetic graph. Theorem 2.3. C8,3,n is a (d ,2d ) --arithmetic graph .
Proof. As the graph shown on fig.3. v1(0)
v2(0)
v 0( 0)
v1(1)
v2(1)
v 0(1)
v 3( 0)
v4(0)
v 3(1)
v1( n−1)
v1(2)
v1(n )
v (0n−1)
v 0( 2)
v4(1)
v (2n−1)
v (3n−1)
v 3( 2)
Fig. 3. The Graf
v 0( n )
v (4n−1)
v 3( n )
C 8, 3, n
Label all vertices as follows:
f (v0( i ) ) = 8id (i = 0,1,2,
, n) ,
f (v3( i ) ) = 4id + 3d (i = 0,1,2,
, n) ,
f (v 4(i ) ) = 8id + 2d (i = 0,1,2,
, n − 1) .
f (v1( i ) ) = 4id + d (i = 0,1,2,
, n) ,
f (v 2( i ) ) = 8id + 6d (i = 0,1,2,
, n − 1) ,
Proof in imitation of Theorem 2.1. For the arbitrary n ∈ N 0 , the mapping f : V (C8,3, n ) → N 0 meet: (1) f (u ) ≠ f (v) when u ≠ v and u, v ∈ V (C8,3,n ) ;
{
,
,
, ,d + (6n + 1) × 2d} .
(2) f (u ) + f (v) uv ∈ E (C8,3,n )} = {d d + 1 × 2d d + 2 × 2d
A Type of Arithmetic Labels about Circulating Ring
395
By (1), (2) we know the mapping f is arithmetic labeling of C 8,3, n . Therefore
C 8,3, n is a (d ,2d ) --arithmetic graph. Theorem 2.4. C8, 4, n is a (d ,2d ) --arithmetic graph.
Proof. As the graph shown on fig.4. v 2( 0 )
v 2(1 )
v (2 n − 1 )
v 2( 2 )
v 2( n )
v 1( 0 )
v 1(1 )
v 1( 2 )
v 1( n − 1 )
v 1( n )
v 3( 0 )
v 3( 1 )
v 3( 2 )
v
( n−1) 3
v 3( n )
v 4( 0 )
v 4(1 )
v (4 n − 1 )
v 4( 2 )
Fig. 4. The Graf
v 4( n )
C 8, 4 , n
Label all vertices as follows:
f (v1(i ) ) = 5id (i = 0,1,2,
f (v 2( i ) ) = 5id + d (i = 0,1,2,
, n) ,
f (v3(i ) ) = 5id + 3d (i = 0,1,2,
, n) ,
f (v 4(i ) ) = 5id + 2d (i = 0,1,2,
, n) , , n) .
Proof in imitation of Theorem 2.2. For the arbitrary n ∈ N 0 , the mapping f : V (C 8, 4,n ) → N 0 meet: (1) f (u ) ≠ f (v) when u ≠ v and u, v ∈ V (C8, 4,n ) ;
{
,
,
, ,d + (5n + 2) × 2d}.
(2) f (u ) + f (v ) uv ∈ E (C8, 4,n )} = = {d d + 1 × 2d d + 2 × 2d
By (1), (2) we know the mapping f is arithmetic labeling of C8, 4, n . Therefore
C 8, 4, n is a (d ,2d ) --arithmetic graph.
3 Labels of Some Special Graph In order to explan the correctness of the aforementioned labels, we give the arithmetic labeling of C8,1,3 C8, 2, 3 C8, 3,3 and C8, 4,3 .
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(1) The arithmetic labeling of C8,1,3 on fig.5.
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(2) The arithmetic labeling of C8, 2,3 on fig.6.
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(4) The arithmetic labeling of C8, 4,3 on fig.8.
d
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References [1] Ma, K.: Gracefulnss. The press of technology, Beijing (1991) [2] Chartrand, G., Lesniak, L.: Graphs and Digraphs. Wadsworth and Brooks/Cole, Monterey (1996) [3] Bondy, J.A., Murty, U.S.R.: Graph Theory with Applications. Elsevier North-Holland (1976) [4] Liu, E.-g., Wu, D., Cai, K.-w.: Two Graphs Arithmetic Labeling. Journal of East China Jiaotong University 26(5), 89–92 (2009) [5] Achaya, B.D., Hegde, S.M.: Arithmetic graphs. Journal of Graph Theory 18(3), 275–299 (1990)
Application of CPLD in Pulse Power for EDM Yang Yang and Yanqing Zhao School of Mechanical and Electronical Engineering, East China Jiaotong University, Nanchang 330013, China [email protected]
Abstract. In order to improve the precision and surface quality of Electrical Discharge Machining (EDM), the paper studies the application of complex programmable logic device (CPLD) used in pulse power for EDM, according to the characteristics of the device, using VHDL language input and schematic input method to design control circuit for EDM pulse power. Keywords: EDM, CPLD, VHDL language, pulse power.
1 Introduction EDM is a special processing method, which makes use of the continuous pulse spark discharge generated by two poles in working fluid, relying on each discharge generates partial and instantaneous high-temperature to ablate down metallic material gradually, cutting into necessary shapes, it is also called as discharge machining or electric erosion processing [1]. Pulse power supply as an important part of machine tools of EDM, provides the required breakdown voltage for processing media, and provides energy to ablate metal after breakdown, its performance is well or not will determine the stability of processing equipment and the height of production efficiency [2, 3]. With the development of EDM application technology, the research on technology of pulse power is more and more in-depth. In the 1980s, it advanced the high and low pressure complex pulse and combshaped pulse (pulse group). Subsequent, it advanced the controlled current rising edge pulse and equal energy pulse, and nowadays has proposed to a new technology which can achieve single discharge pulse detection. Now people study of the pulse power variable parameters more refined, parameter adjustment and digital level higher. In this case, if it continues to use discrete components or small and medium-scale integrated circuits as the basic original, obviously doesn’t meet the design requirements of power nowadays with high integrated, fast changing, good controllability. From 80 to 90 during the 20th century made the high and low pressure complex, comb-shaped pulse (pulse packet), the subsequent rising edge of control current, such as the energy pulse, and has proposed to achieve a single discharge pulse detection technology, people Pulse variable parameters of a more detailed, parameter adjustment and further quantify the number of higher degree. In this case, the EDM pulse power supply circuit such as to continue to use discrete components and small and mediumscale integrated circuits as the basic original, obviously does not meet today's power highly integrated, fast changing, good controllability of the design requirements. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 398–402, 2011. © IFIP International Federation for Information Processing 2011
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2 Characteristics of CPLD Devices The first programmable logic device - PLD was produced in the 1970s, and it’s output structure is programmable logic macrocell, because the design of hardware architecture was completed by the software, which like that workers designed the interior structure after the house completed, so its design is more flexible than pure software on digital circuits. But its structure is too simple so that they only can achieve smaller circuits. To make up for the flaw that PLD only can design smallscale circuit, in the middle of 1980s, the complex programmable logic device was invented– CPLD [4, 5]. With programming flexibility, high integration, design and development period is short, wide scope of application, development tools is advanced, low costs of design and manufacturing, the experience of the designers requirements low, standard products without testing, confidentiality, price moderate, etc, and it can realize largescale circuit design, so the complex programmable logic device – CPLD is widely used in prototype of product design and production (In general under 10,000 pieces). Almost all the situation where small scale general digital circuits were applied can applied CPLD device. In recent years, because advanced integration process was Adopted, CPLD device was produced in quantity and its costs continue to drop. Integrated density, velocity, and has been greatly improved. And its integrated density, velocity, capability has been greatly improved. Because it has a lot of advantages, such as high reliability, excellent electromagnetic compatibility (EMC) and micro-power consumption, CPLD has been widely used in the field of numerical control. What is particularly important is that CPLD has the function of online programming (ISP) (according to different requirements, just a software reprogramming, you can complete the online programming), which makes function update and system debugging more convenient and greatly shorten the product development cycle, also it is great convenience to design and modify.
3 EDM Pulse Power Circuit Structure This pulse power takes CPLD and MOSFET as the core component. Through the programming on the CPLD, it can realize the steering impulse adjustment. This pulse takes the driving of circuit applied to the MOSFET as the power switch, and provides pulse power for the processing circuit. The power schematic is shown in Figure 1. CPLD can construct digital logic integrated circuits for users’ own needs, and it is suitable to be used to realize each kind of operation and combinatory logic. Furthermore, it can achieve large-scale circuit design for its many kinds of characteristics, such as programming flexibility, high integration, advanced develop kit, low design cost and so on. ALTERA’s MAXII series chips are high speed and support for the global maximum input clock frequency up to 304 MHz. By using the chip to carry on the pulse control signal disposition, it can output the disposition information for the external instrumentation, simultaneously may receive the superior information.
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Fig. 1. Schematic diagram of pulse power
4 CPLD Devices of Control Circuit for Pulse Power Design Pulses control program principle framework is shown in Figure 2. It set the required time parameters for pulse high and low, mainly through the multiplexer time-sharing operation to the next level. The multiplexer selection is carried out by the output adjusting. When time parameters through the multiplexer, it immediately starts the counter to count, and loop checks whether the given parameters are equal. If they are equal, the program sends a corresponding pulse to the retainer, and triggers the inverter for inverting operation. Pulses are from the inverter output.
Fig. 2. Pulses control program principle framework
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Pulses control program flow chart is shown in Figure 3. Pulse parameters on-time and off-time represent the pulse width and pulse interval and set by the DIP switch, according to the value of signal sel, put the values of on-time and off-time to variables time-count. If time-count is 0, then signal sel is negated, and sel takes counter-action in the next clock, at the same time take anti-variable temp, and the value assigns to the output signal out-value. If time-count is not 0, then enter the next statement. Every clock cycle, the variable Counter plus one, and compared with the variable timecount. The role of variable Counter is allocating time as a counter with the given pulse parameters. When Counter equals time-count, input signal sel is negated, and initialize the Counter, then take anti-signal temp to output values.
Fig. 3. Pulses control program flow chart
In the VHDL design, two common objects are signal and variable [6], signal is a means of date exchange in the design entity, using signal objects can connect design entity to form module, representative of a hardware circuit in the hardware connection, sometimes the signal will be integrated into register, while variable mainly stores temporary data locally, it is a local variable. Within a process, signal processing is delayed, namely only after the arrival of the next clock for signal processing, but the variable processing is real-time. Therefore, after entering the process, the signal of On-time and Off-time need to be converted to variable form. Variable of Time-Count judging and variable of Count computing are real-time. When Time-Count equals 0, that is, the high pulse or low pulse is a clock cycle, and the program directly jumps out from process. The minimum output pulse increased to a clock cycle by the pulse entering output value .after using QUARTUSII simulation, waveform is shown in Figure 4.
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Fig. 4. Pulses width 10ns and inter-pulse 50ns simulation graph
CPLD uses the source crystal oscillator to provide clock pulses, taking into account the conduction ability of MOSFET .we choose 100M crystal which can provide minimum pulse period of 10ns.
5 Conclusions The designed control circuit has many advantages, such as stable performance, strong anti-interference ability, precise pulses, good scalability, fully embodies the characteristics of CPLD devices. The CPLD devices applied to the design of EDM pulse power, improved the flexibility of circuit design, reduced PCB area, increased power system reliability, shortened product development cycle, and reduced design costs and application costs, it can meet the increasingly complex electronic processing equipment control circuit applications.
References [1] Liu, J., Zhao, J., Zhao, W.: Special machining, 4th edn., pp. 7–61. Mechanical Industry Press (2004) [2] Gao, C., Song, X., Liu, Z.: Research on a Micro Energy Pulse Power Supply for MicroEDM. Aviation Precision Manufacturing Technology, 9–11 (1997) [3] Han, F., Yamada, Y., Kawakami, T., Kunieda, M.: Experimental Attempts of SubMicrometer Order Size Machining Using Micro-EDM. Precision Engineering 30(2), 123– 131 (2005) [4] Liao, Y., Lu, R.: CPLD digital circuit design. Tsinghua University Press, Beijing (2001) [5] Xue, Z.: Application of CPLD in pulse power of EDM. Electromachining & Mould (1), 20–21 (2003) [6] Zhao, S., Yang, F., Liu, J.: VHDL and computer interface design. Tsinghua University Press, Beijing (2004)
Application of IDL and ENVI Redevelopment in Hyperspectral Image Preprocessing Long Xue School of Mechanical and Electronical Engineering, East China JiaoTong University, Nanchang 330013, China [email protected] Abstract. In the last few years, hyperspectral imaging technique has had a bright future for application on nondestructive detection of agricultural products. However, in experiment, there are usually dozens or even hundreds of hyperspectral images. It needs to spend lots of time in preprocessing all the hyperspectral data. Software ENVI is a kind of image processing software, although the users can define their own algorithms and apply to the opened bands in ENVI or the bands and spectra operation of the images, it doesn’t provide program to batch process. In this paper, the custom function “normalized” of Interactive Data Language (IDL) is applied to achieve batch processing on multiple hyperspectral images. Keywords: ENVI, redevelopment, hyperspectral image.
1 Introduction Software ENVI (The Environment for Visualizing Images) is image processing software. It is developed by the sciences of remote sensing using Interactive Data Language (IDL). It combines the latest spectral image processing and image analysis technology with an intuitive, user-friendly interface to help you get meaningful information from imagery. It can fast, conveniently, correctly extract information from geography and special image data. Therefore, it has been widely used in science research, environment protection, meteorology, agriculture, mineral and petroleum exploration. Since hyperspectral image combines the character of image and spectrum, so it is applied in agricultural product quality, food safety and nondestructive detection. At home, Hong Tiansheng et al. built prediction model of Chinese pear quality based on hyperspectral imaging technique and artificial neural network [1]. Zhao Jiewen et al. detected the subtle bruises on apple using hyperspectral image [2]. Liu Muhua et al. nondestructively detected soluble solids content and contamination on navel orange surface by hyperspectral laser-induced fluorescence imaging [3-4]. At abroad, M. S. Kim et al. detected fecal contamination on apple, cantaloupes using hyperspectral fluorescence imagery [5-8]. Juan Xing et al. detected surface defects on tomatoes by a hyperspectral imaging system [9]. In experiment, there are usually tens to hundreds of acquired hyperspectral images, and the images need to be preprocessed. Although ENVI software offers interactive computing functions of spectral bands and spectrum, the same preprocessing of hundreds of images takes considerable time and is a very boring job. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 403–409, 2011. © IFIP International Federation for Information Processing 2011
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This article uses IDL to write a batch program module based on ENVI, which can achieve the normalization preprocessing of the spectral data.
2 IDL and ENVI Redevelopment 2.1 IDL Introduction IDL is the ideal, timesaving solution for data analysis, data visualization, and software application development. The users can quickly and easily use this software to convert the data to images. The converted images can be simple color, full color or threedimensional images. As ENVI software provides the function interface of IDL, so the users can use the built-in IDL functional components, IDL users function, or a custom program. However, these functions must be kept in a directory of ENVI path list to be automatically compiled. 2.2 Spectral Data Preprocessing Because the uneven distribution of light source intensity under the different wave bands and the presence of dark current noise of camera, so the images may contain more noises in some wave bands, therefore, the hyperspectral images must be normalized. Under the same experimental condition, the image of a stand white plate was acquired. The dark image was acquired by completely covering the lens with its cap. The normalization preprocessing is achieved according to equation (1):
I norm = Where:
I sample − I dark I reference − I dark
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I norm ——the pixel value of the image after normalized preprocessing; I sample ——the pixel value of a sample image; I reference ——the pixel value of standard white plate;
I dark ——the pixel value of the dark image. 2.3 ENVI Redevelopment The most common method of ENVI software redevelopment is using IDL to develop small application program modules, and call these modules. Meantime, these modules must be stored in the directory “X:\RSI\IDLXX\products\enviXX\save_add” to be compiled automatically. In this article, the hyperspectral files to be processed were saved in the directory “X:\original\”, and a total of n hyperspectral files were named according to numerical order (such as DH1.raw, DH2.raw, ..., DHn.raw). In the folder,The standard white plate hyperspectral image (white.raw) and the dark hyperspectral image (black.raw) were saved in the same folder. After preprocessing, the hyperspectral files were stored in the directory “x: \ normalized \ folder”, the program code is as follows:
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; Building the patch processing program module of hyperspectral images “normalized”. The function is to normalize the original images. pro normalized ; Setting the path of hyperspectral files to be processed. inpath=' X:\original\' ; Setting the path of hyperspectral files having been processed. outpath=' X:\normalized\' ; Defining the array “filename” which was used to store the file name of dark image and standard white plate image. filename = ['black.raw', 'white.raw'] ; read the hyperspectral files, L represents the data is numerical type. for j=1L,nL do begin ; Converting data from numerical type to character type num=string(format='(i0)',j) ; Saving the path and file name of a specific hyperspectral file with “in_name” in_name0=inpath+num+'.raw' ; Printing the file name in IDL screen to express the processing course print,in_name0 ; Opening the file, option “no_realize” represents that the file will not be opened in available band list, and “fid” is the number of the file. envi_open_file, in_name0,/no_realize, r_fid=fid ; Opening the dark and standard white plate images. in_name1=inpath+filename[0] in_name2=inpath+filename[1] envi_open_file, in_name1,/no_realize,r_fid=fid2 envi_open_file, in_name2,/no_realize,r_fid=fid3 ; Accessing file’s information, “ns” represents the sample number of the file, “nl” represents the number of lines, “nb” represent the number of bands, “xstart” and “ystart” represents the pixel
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coordinates of the top left corner in the image and the default value is (1,1). envi_file_query, fid, interleave=interleave,ns=ns, nl=nl, nb=nb,dims=dims, data_type=_datatype, xstart=_xstart, ystart=_ystart,SPEC_NAMES=SPEC_NAMES ; “dims” is the spectral range to be processed. “Ssn” represents the first file, and “esn” represents the last file. “sln” represents the first line of the file, and “eln” is the last line. pos=lindgen(nb) dims=[-1l,ssn,esn,sln,eln] envi_file_query, fid2, interleave=interleave2 envi_file_query, fid3, interleave=interleave3 ; Setting the command blocks. tile_id=envi_init_tile(fid,pos,num_tiles=num_tiles, interleave=interleave>1,xs=dims[1],xe=dims[2],ys=di ms[3],ye=dims[4]) tile_id2=envi_init_tile(fid2,pos,num_tiles=num_tiles, interleave=interleave>1,xs=dims[1],xe=dims[2],ys=di ms[3],ye=dims[4]) tile_id3=envi_init_tile(fid3,pos,num_tiles=num_tiles, interleave=interleave>1,xs=dims[1],xe=dims[2],ys=di ms[3],ye=dims[4]) ; Processing each block data, and saving the file in the directory “x:\normalized\” openw, _unit, outpath+num+'.raw', /get_lun for i=0L, num_tiles-1 do begin data = envi_get_tile(tile_id, i) data2 = envi_get_tile(tile_id2, i) data3 = envi_get_tile(tile_id3, i) data4=(float(data)-float(data2))/( float(data3)float(data2)) writeu, _unit,data4 endfor free_lun, _unit ; Building the head file.
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envi_setup_head, fname=outpath+aa, ns=dims[2]dims[1]+1,nl=dims[4]-dims[1]+1, nb=nb,data_type=4, offset=0, interleave=interleave,xstart=_xstart+dims[1], ystart=_ystart+dims[3],descrip=' Normalized file', /write ; Releasing the command block. envi_tile_done, tile_id envi_tile_done, tile_id2 envi_tile_done, tile_id3 envi_file_mng,id=fid,/remove envi_file_mng,id=fid2,/remove envi_file_mng,id=fid3,/remove ; Printing the number of a file which has been processed. print,num close,/all,/force endfor envi_batch_exit end The image of pear at 680nm before preprocessing is shown in Figure 1. From figure 1, the obvious strip in the image is found easily. Figure 2 show the image of pear at 680nm after preprocessing, the quality of image is improved greatly.
Fig. 1. Image of pear at 680nm before preprocessing
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Fig. 2. Image of pear at 680nm after preprocessing
Figure 3 show the average visible and near-infrared spectra in the 500 to 950nm region of the pear, (a) before preprocessing, (b) after preprocessing.
(a) Before preprocessing
(b) After preprocessing Fig. 3. The average visible and near-infrared spectra in the 500 to 950nm region of the pear
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3 Conclusion By using IDL language and ENVI redevelopment, an extensible remote sensing system with perfect functions can be developed. Nowadays, this system is further expansion because more and more research achievements are integrated in it by scientific researchers. The strong abilities of IDL language and ENV redevelopment make the scientific researchers can release from boring programming work to invest more time and effort to actual research.
References [1] Hong, T., Qiao, J., Wang, N., et al.: Non-destructive inspection of Chinese pear quality based on hyperspectral imaging technique. Transactions of the CSAE 23(2), 151–155 (2007) [2] Zhao, J., Liu, J., Chen, Q., Saritporn, V.: Detecting Subtle Bruises on Fruits with Hyperspectral Imaging. Transactions of the Chinese Society for Agricultural Machinery 1(31), 106–109 (2008) [3] Guo, E., Liu, M., Zhao, J., Chen, Q.: Nondestructive Detection of Sugar Content on Navel Orange with Hyperspectral Imaging. Transactions of the Chinese Society for Agricultural Machinery 39(05), 91–93, 103 (2008) [4] Xue, L., Li, J., Liu, M.: Detecting Pesticide Residue on Navel Orange Surface by Using Hyperspectral Imaging. Acta Optica Sinica 28(12), 2277–2280 (2008) [5] Kim Moon, S., Lefcourt, A.M., Chen, Y.-R.: Ns-scale time-resolved laser induced fluorescence imaging fordetection of fecal contamination on apples. In: SPIE 2004, vol. 5587, pp. 190–197 (2004) [6] Vargas, A.M., Kim, M.S., Tao, Y., Lefcourt, A., Chen, Y.-R.: Safety Inspection of Cantaloupes and Strawberries Using Multispectral Fluorescence Imaging Techniques. ASAE Paper, No. 043056. St. Joseph. ASAE, Mich. (2006) [7] Kim, M.S., Lefcourt, A.M., Chen, Y.-R.: Automated detection of fecal contamination of apples based on multispectral fluorescence image fusion. J. Food Engineering 71, 85–91 (2005) [8] Lee, K-J., Kang, S., Kim, M.S.: Hyperspectral imaging for detecting defect on apples. ASABE Paper No. 053075. St. Joseph. ASABE, Mich. (2005) [9] Xing, J., Ngadi, M., Wang, N.: Wavelength Selection for Surface Defects Detection on Tomatoes by Means of a Hyperspectral Imaging System. ASAE Paper, No. 063018 St. Joseph. ASAE, Mich. (2006)
Design of Integrated Error Compensating System for the Portable Flexible CMMs Qing-Song Cao, Jie Zhu, Zhi-Fan Gao, and Guo-Liang Xiong College of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang 330013, China
Abstract. During the working of portable flexible CMM, the mechanical arm’s gravity and operating load generate dynamic strain, the thermal distortion also results in its length change. The caused errors would severely deteriorate the measuring accuracy. An error compensating system of the mechanical arm is designed in this paper, based on the monitor of dynamic strain and environmental temperature. The mathematical model of portable flexible coordinate measuring machine (CMM) was established.For the dynamic strain, four resistance strain gauges are sticked symmetrically on the root of each mechanical arm to monitor the dynamic strain. Then length error caused by the measuring arm’s gravity or external operation load can be calculated through the analysis of stress. Strain compensation can be realized, when they are fed back to the measurement procedures. For thermal distortion, the temperature values acquired by the single-linear digital thermometer are substituted in the correction formula to calculate the relevant compensation dosage. Finally, these compensation dosages are feedbacked to the measuring program to have these errors compensated continually. The integrated error compensation system can improve the measurement accuracy of portable flexible CMM effectively. Keywords: flexible arm, coordinates measuring machine, strain, temperature, error compensation.
1 Introduction The traditional orthogonal coordinate measuring machines (CMMs) have the advantage of simple kinematical model and high measuring accuracy. However, with the development of the modernization of industry and manufacture, the limitations of traditional perpendicular CMMs also increasingly exposed to us, which can not meet the application requirements in many cases. The flexible CMMs connect arm through revolting joint by turn, which is a new type of multiple degree and non-Cartesian system. It has the advantage of smaller volume, lighter weight, larger measuring range, portable and barrier-free measure compared with the traditional orthogonal CMMs. It is particularly suitable for the on-site mobile measure and it has gradually become the developing trend of the measurement field. However, due to its totally new structure, the mathematical modeling procedure is no longer simple on the one hand. On the other hand, the error of each joint will be seriously magnified by the measuring arm, and it will seriously affect the measurement accuracy. Therefore detecting and compensating for this error is very necessary. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 410–419, 2011. © IFIP International Federation for Information Processing 2011
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For flexible CMMs, the rotation angle of each joint, along with the mechanical parameters including length of each measuring arms and offset of every two joints etc, are substituted the kinematical model built by D-H coordinate transform method. Then the measurement of 3-D coordinates can be realized. Therefore, the precision of 3-D coordinates is directly influenced by the angle error of each joint and the length error of every mechanical arm, to ensure the measuring accuracy error compensation system must be estblished. Ye et al. [1, 2] considered error of the structural parameters during the machining and assembling process as the largest error source, and correct ideal model of the CMMs to get its error model. In this way, the measurement accuracy is greatly improved. Wang et al. [3] analyzed various factors that affect measurement results in detail, and consider that the processing and assemble error, the environmental temperature and strain, etc. affect the measurement precision of the CMMs. Wang [4] analyzed the impacts on the measuring results caused by external environment such as temperature, humidity and external power, and presented several measures that should be taken to reduce them.
2 The Principle of Compensation for Integrated Error 2.1 Mathematical Model of the CMM Portable CMM adopts the whole serial revolted-joint structure, the relative position and posture between every two rods is the basis of coordinate measuring. And coordinate system of each rod should be built for the analysis of this relationship between them [5]. In 1955 Denavit and Hartenberg put forward the famous D-H homogeneous transformation method. By this method, 6 DOF coordinate system for structure schematic diagram of the CMM is built, as shown in Fig.1. Z3
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Fig. 1. Coordinates of the portable CMM
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The coordinate transformation matrix of coordinates from number i+1 to number i is signed asTi-1i. A CMM with n joints, the coordinate transformation matrixes of coordinate system are as below.
Tnn −1 , Tnn−−12 ,..., T21 , T10 If the position of one point in the final coordinate system is known, then coordinates of the measuring head in the base coordinate system can be obtained through continuous transformation of coordinate systems. On the basis of the coordinate systems built above and D-H coordinate transformation principle, the coordinate transformation matrix of the measuring head with respect to the base coordinate system can be expressed as
⎡1 ⎢0 A = T10T21T32T43T54T65T76 = ⎢ ⎢0 ⎢ ⎣0
⎡ cos θ1 0 sin θ1 ⎢ sin θ 1 − cos θ 1 1 ×⎢ ⎢ 0 0 0 ⎢ 0 0 ⎣ 0 ⎡ cos θ3 ⎢ sin θ 3 ×⎢ ⎢ 0 ⎢ ⎣ 0
0 sin θ 3 0 − cos θ 3 1 0 0 0
⎡ − sin θ5 ⎢ cos θ 5 ×⎢ ⎢ 0 ⎢ ⎣ 0
0 cos θ5 0 sin θ 5 1 0 0 0
L3 cos θ1 ⎤ ⎡ cos θ 2 L3 sin θ1 ⎥⎥ ⎢⎢ sin θ 2 × L2 ⎥ ⎢ 0 ⎥ ⎢ 1 ⎦ ⎣ 0
0⎤ 1 0 0 ⎥⎥ 0 1 L1 ⎥ ⎥ 0 0 1⎦ 0 0
L4 cos θ 2 ⎤ 0 − cos θ 2 L4 sin θ 2 ⎥⎥ ⎥ 1 0 0 ⎥ 0 0 1 ⎦ L6 cos θ 3 ⎤ ⎡ − sin θ 4 0 − cos θ 4 L7 cos θ 4 ⎤ L6 sin θ 3 ⎥⎥ ⎢⎢ cos θ 4 0 − sin θ 4 L7 sin θ 4 ⎥⎥ × ⎥ L5 ⎥ ⎢ 0 −1 0 0 ⎥ ⎢ ⎥ 1 0 0 1 ⎦ ⎣ 0 ⎦ L9 cos θ5 ⎤ ⎡ cos θ 6 0 si n θ 6 L10 sin θ 6 ⎤ L9 sin θ 5 ⎥⎥ ⎢⎢ sin θ 6 0 cos θ 6 L10 cos θ 6 ⎥⎥ × ⎥ L2 ⎥ ⎢ 0 1 0 0 ⎥ ⎢ ⎥ 1 0 0 1 ⎦ ⎣ 0 ⎦ 0
sin θ 2
(1)
As can be deduced from this mathematical model, the measurement result depend on the arms length Li and the joint’s rotating angle θi , the error of the arms length and the joint’s rotating angle affected measuring accuracy directly. 2.2 Principle of Compensation for Temperature Error
During the measurement procedure, the environmental temperature should be kept as constant as possible. If not, the deviation of the temperature from the reference of 20 will result in difference between real length and ideal length of each rod, which
℃
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should not be neglected. For this kind of difference, temperature element is sticked to the rod to monitor its temperature, and then get it processed to get the relevant compensation dosage. The formula of the compensation dosage is ΔLi = (T − 20 ) × α i
(2)
In this formula, T is the environmental temperature, αi is thermal expansion coefficient of the material. So when the affection of thermal variation on the measuring results is considered, and the compensation dosage is added to the ideal mathematical model, we can get the mathematical model with errors of temperature variation as follow ⎡1 ⎢0 A' = T10T21T32T43T54T65T76 = ⎢ ⎢0 ⎢ ⎣0 ⎡cos θ1 ⎢ sin θ 1 ×⎢ ⎢ 0 ⎢ ⎣ 0
0 sin θ1 1 − cos θ1 0 0 0 0
⎡ cos θ3 ⎢ sin θ 3 ×⎢ ⎢ 0 ⎢ ⎣ 0
0 sin θ3 0 − cos θ3 1 0 0 0
⎡ − sin θ5 ⎢ cos θ 5 ×⎢ ⎢ 0 ⎢ ⎣ 0
0 cos θ5 0 sin θ 5 1 0 0 0
0 1 0 0
( L3 + ΔL3 ) cos θ1 ⎤ ⎡cos θ 2 ( L3 + ΔL3 ) sin θ1 ⎥⎥ ⎢⎢ sin θ 2 × ⎥ ⎢ 0 L2 + ΔL2 ⎥ ⎢ 1 ⎦ ⎣ 0
0 0 ⎤ 0 0 ⎥⎥ 1 L1 + ΔL1 ⎥ ⎥ 0 1 ⎦ 0 sin θ 2 0 − cos θ 2 1 0 0 0
( L4 + ΔL4 ) cos θ 2 ⎤ ( L4 + ΔL4 )sin θ 2 ⎥⎥ ⎥ 0 ⎥ 1 ⎦ ( L6 + ΔL6 ) cos θ3 ⎤ ⎡ − sin θ 4 0 − cos θ 4 ( L7 + ΔL7 ) cos θ 4 ⎤ 0 − sin θ 4 ( L7 + ΔL7 ) sin θ 4 ⎥⎥ ( L6 + ΔL6 ) sin θ 3 ⎥⎥ ⎢⎢ cos θ 4 × ⎥ ⎢ 0 ⎥ −1 0 0 L5 + ΔL5 ⎥ ⎢ ⎥ 1 0 0 1 ⎦ ⎣ 0 ⎦ ( L9 + ΔL9 ) cos θ5 ⎤ ⎡ cos θ 6 0 si n θ6 ( L10 + ΔL10 ) sin θ 6 ⎤ ( L9 + ΔL9 ) sin θ 5 ⎥⎥ ⎢⎢ sin θ 6 0 cos θ 6 ( L10 + ΔL10 ) cos θ 6 ⎥⎥ × ⎥ ⎥ ⎢ 0 L2 + ΔL2 1 0 0 ⎥ ⎥ ⎢ 1 0 0 1 ⎦ ⎦ ⎣ 0 (3)
2.3 Principle of Compensation for Strain Error
In the measurement procedure, the bending deformation on measurement arm will result in the extra rotating angle of each joint. As the angle deviation would be seriously magnified through the arm, the impact caused must not be neglected. The bending deformation caused by the operation force can be detected by strain gages sticked symmetrically around the measuring arm. The bridge type is most frequently used, which can amplify signal effectively. The circuit diagram for strain measurement is shown in fig.2.
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strain B
strain A
R-ǻR R+ǻR
U0 Amplification
A/D conversion
MCU
R
R
E
Fig. 2. Block diagram of strain-measuring circuit
As is shown in the figure, the bridge is in state of equilibrium, and there are no signals output when the measuring arm is not forced. Two strains are sticked on the adjacent bridge arms. The resistance of strain A gets bigger and that of strain B decreases when the arm is exposed to stress, the bridge is no longer balanced, and there is voltage signal output in this situation. As resistance strain is used in this paper, this signal is very weak, and it must be amplified first so that it can be treated afterwards. According to the above shows that can block, amplified output voltage of bridge road can be expressed as U0 =
K 0 ⋅ K ⋅ E ⋅ ΔL 2⋅ L
(4)
Where, E is the input voltage, K is the sensitivity coefficient of the strain gauge selected, L is the length of the measuring arm. So the length variation of measuring arm can be obtained and expressed as ΔL =
2 ⋅U 0 ⋅ L E ⋅ K ⋅ K0
(5)
And the corresponding extra rotation angle of the joint is ⎞ L ⋅ E ⋅ K ⋅ K0 ⎛ L ⎞ −1 ⎛ Δθ = cos −1 ⎜ ⎟ ⎟ = cos ⎜ ⎝ L + ΔL ⎠ ⎝ 2 ⋅ L ⋅U 0 + L ⋅ E ⋅ K ⋅ K0 ⎠
△
(6)
Namely, this θ is the extra rotation angle of each joint caused by the measuring arm’s own gravity or external operation force. And it is used as the compensation
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value and is substitute to mathematical model of the CMMs. So mathematical model with strain error can be expressed as ⎡1 ⎢0 A'' = T10T21T32T43T54T65T76 = ⎢ ⎢0 ⎢ ⎣0
0 1 0 0
0 0⎤ 0 0 ⎥⎥ 1 L1 ⎥ ⎥ 0 1⎦
⎡cos(θ1 + Δθ1 ) ⎢ sin(θ + Δθ ) 1 1 ×⎢ ⎢ 0 ⎢ 0 ⎣
0 sin(θ1 + Δθ1 ) L3 cos(θ1 + Δθ1 ) ⎤ ⎡cos(θ2 + Δθ2 ) 0 sin(θ2 + Δθ2 ) L4 cos(θ2 + Δθ2 ) ⎤ 1 − cos(θ1 + Δθ1 ) L3 sin(θ1 + Δθ1 ) ⎥⎥ ⎢⎢ sin(θ2 + Δθ2 ) 0 − cos(θ2 + Δθ2 ) L4 sin(θ2 + Δθ2 ) ⎥⎥ × ⎥ ⎢ ⎥ 0 0 L2 0 1 0 0 ⎥ ⎢ ⎥ 0 0 1 0 0 0 1 ⎦ ⎣ ⎦ ⎡cos(θ3 + Δθ3 ) 0 sin(θ3 + Δθ3 ) L6 cos(θ3 + Δθ3 )⎤ ⎡− sin(θ4 + Δθ4 ) 0 − cos(θ4 + Δθ4 ) L7 cos(θ4 + Δθ4 )⎤ ⎢ sin(θ + Δθ ) 0 − cos(θ + Δθ ) L sin(θ + Δθ ) ⎥ ⎢ cos(θ + Δθ ) 0 − sin(θ + Δθ ) L sin(θ + Δθ ) ⎥ 3 3 3 3 6 3 3 ⎥ ⎢ 4 4 4 4 7 4 4 ⎥ ×⎢ × ⎢ ⎥ ⎢ ⎥ 0 1 0 L5 0 0 0 −1 ⎢ ⎥ ⎢ ⎥ 0 0 0 1 0 0 0 1 ⎣ ⎦ ⎣ ⎦ ⎡ − sin(θ5 + Δθ5 ) 0 cos(θ5 + Δθ5 ) L9 cos(θ5 + Δθ5 ) ⎤ ⎡cos(θ6 + Δθ6 ) 0 si n(θ6 + Δθ6 ) L10 sin(θ6 + Δθ6 ) ⎤ ⎢ cos(θ + Δθ ) 0 sin(θ + Δθ ) L sin(θ + Δθ ) ⎥ ⎢ sin(θ + Δθ ) 0 cos(θ + Δθ ) L cos(θ + Δθ ) ⎥ 5 5 5 5 9 5 5 ⎥ ⎢ 6 6 6 6 10 6 6 ⎥ × ×⎢ ⎢ ⎥ ⎢ ⎥ L2 0 1 0 0 1 0 0 ⎢ ⎥ ⎢ ⎥ 0 0 0 1 0 0 0 1 ⎣ ⎦ ⎣ ⎦
(7)
3 Design of the Compensation System for Integrated Errors 3.1 Overall Scheme
To achieve compensation for errors caused by thermal change and strain, a compensation system is designed in this paper, which consists of the acquisition of temperature and strain, the calculation of compensation dosage and the modification of corresponding mathematical model. The overall diagram is shown in Figure 3.
Temperature detector
Strain Gauge
Thermal value
Strain value
Processing program 1 on PC
Processing program 2 on PC
Compensation dosage 1
Compensation dosage 2
Mathematical model To achieve
Fig. 3. Overall diagram of the error compensation system
Modified mathematical model
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3.2 Design of the Error Compensation System of Temperature
As we know, most materials expand as the temperature increases and contract when they are cooled. The flexible arm CMMs are operated by people and are often used in workshop. The environmental temperature changes and the heat created by the electronic devices in the CMMs would result in length change of measuring arm. Therefore, measures have to be taken to modify these errors. A new single-wire enhanced digital thermometer DS18B20 [6], which is produced by the DALLAS Corporation, is used in this paper. The measuring rang of temperature of this sensor is -55 ~ 125 and the measurement accuracy is ± 0.5 among -10~ 85 . As the sensor adopts a single-wire structure, the information can be sent or output by a single-wire interface, and the PC can read, write and convert the temperature through an I/O line. In addition, the sensor can achieve multiple points of temperature measurement, thus it can reduce the amount of line for temperature measurement [7]. The temperature measurement circuit is shown in figure 4.
℃
℃
℃,
Fig. 4. Measurement circuit of temperature
The measuring circuit of thermal variation is very simple, and its function is mainly accomplished by software. The program diagram is shown in figure 5.
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Reset
Precision setting
Temperature value error CRC correct Temperature processing
Temperature display
Sending data
End
Fig. 5. Program diagram of thermal measurement
The temperature obtained from the single-wire digital thermometer DS18B20 is sent to computer through serial communication, and then it is compared with the ideal temperature of 20 to get the corresponding length change, using the thermal expansion coefficient of the selected material. On the PC, LabVIEW is used to obtain and calculate the compensation dosage of the corresponding temperature through serial communication. The program diagram is shown in figure 6.
℃
Fig. 6. Program diagram of thermal error compensation
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3.3 Design of the Error Compensation System of Strain
The arm of flexible CMM usually adopts long and thin circular pipe, so it is easy to bend and deform under its own gravity and the exterior operation power. Previous studies showed that it creates bending deformation of more than 10″at the two ends of the arm is very common. This is one of the most important factors limiting the measuring accuracy of this kind of CMMs. The bending and deformation of CMM’s each arm is not only in relation to the structural parameters of the arm, but also to the extension of the arm. It is difficult to calculate the amount of the bending and deformation of the arm precisely by theoretical calculation. So it is necessary to paste numbers of strain gauges to monitor deformation on each arm, and then make corresponding program to compensate for the errors immediately. The bending and deformation of measuring arm is equal to increase the rotation angle of each joint additionally. Strain gauges are pasted symmetrically on the arm to monitor the bending and deformation along the axis in this paper. The strain gauges are linked as form of half bridge, and circuit of strain measurement is shown in figure 7.
Fig. 7. Circuit of strain measurement
The amplified output voltage of the bridge is an analog quantity, and it must be converted to by A/D converting circuit as the MCU can only obtain and deal with the digital quantity. The A/D converting circuit is shown in figure 8. The programs compiled with LabVIEW on the PC for strain measurement is just like that of the temperature, we can replace the formula with the formulae 6 above. Take into account fully, the error of environmental thermal variation and dynamic strain was compiled with LabVIEW thus the Complete error compensation system was established. It is also the key technology to improve the measurement accuracy.
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Fig. 8. A/D convertion circuit
4 Conclusion Firstly, the ideal mathematical model of the portable CMM is established in this paper, and then the mathematical model with errors is established on the basis of analysis of parts of the error sources. At last an error compensation system based on environmental thermal variation and dynamic strain is designed from two aspects of hardware and software, the integrated error compensation system can improve the measurement accuracy of portable flexible CMM effectively.
References 1. Ye, D., Huang, Q. C., Che, R. S.: Error modeling for multi-joint coordinate measuring machine. J. Optics and Precision Engineering 7(2), 92–96 (1999) 2. Ye, D., Che, R.S.: Modeling and error analysis for Human-simulating multi-joint coordinate measuring machine. Journal of Harbin Institude of Technology 31(2), 28–32 (1999) 3. Wang, X.Y., Liu, S.G., Zhang, G.X.: Mathematical Model and error Analysis of the Articulated Arm Flexible CMM. J. Nanotechnology and Precission Engineering 3(4), 262–267 (2005) 4. Xu, J.X.: The develop of portable Articulated Arm CMM. D. Research institute of mechanical science, Beijing, (2007) 5. Li, Z.W., Wang, C.J., Zhou, X.H.: Mathematical Model and Parameter Calibration of the multi-joint coordinate measuring machine. J. Mechanical Processing Technology and Equipment (6), 35–36 (2006) 6. Denavit, J., Hartenberg, R.: A kinematic notation for lower pair mechanism based on matrices. J. ASME Journal of Applied Mechnics 22(6), 215–221 (1955) 7. Chen, T.: Application of Single Chip Processor and C language programming. China Machine Press, Beijing (2008)
Detecting and Analyzing System for the Vibration Comfort of Car Seats Based on LabVIEW Ying Qiu Key Laboratory of Conveyance and Equipment, Ministry of Education School of Mechanical and Electronical Engineering, East China Jiaotong University, Nanchang, P.R. China [email protected]
Abstract. In this research, LabVIEW 8.5 is taken as the software platform. Sensors, data acquisition cards are combined as its hardware. A detecting and analyzing system for the vibration comfort of car seats is developed, in which the functions as to the collecting and processing of vibrating signals, the access of data and the display of images are achieved. The system can also analyze the dynamic characteristics and the comfort of the occupant-seat system. By choosing different seat characteristics according to different vehicle environments, the best comfort can be obtained. In addition, it also provides some favorable references to the designing of safe and comfortable automobile seats. Keywords: Vehicle seat, LABVIEW, Dynamic characteristics, Vibration detection.
1 Introduction Car seat is an important part of the car. Its main function is to support the driver and the passenger's body, to reduce the impact on the body aroused by rough road surface and to attenuate the resulting vibrations. With the improvement of living standard and the rapid development of automobile technology, the demand for automotive comfort is higher and higher. Automotive comfort includes static and dynamic comfort. The former mainly involves size parameters, surface quality and the regulation characteristics; and the latter is largely related to vibration characteristics. In mechanical vibration test, because numerous complex test equipment are needed, a simple test may even require great manpower and large quantity of material resources, not to mention some complex work like the vibration test on car seats. With the development of computer and software technology, it is taking over the traditional method and is becoming the trend in the area of testing. In this article, a development platform based on LabVIEW software (a virtual instrument platform initiated by American National Instruments Company) is constructed. Necessary sensor, signal conditioners and data acquisition cards are taken as the main hardware to build a detecting and analyzing system for the seat vibration test. Results from experiments show that the suggested D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 420–426, 2011. © IFIP International Federation for Information Processing 2011
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system can effectively fulfill the work of acquiring and processing seat vibration signals, analyzing its dynamic characteristics and assessing its comfort rate.
2 Overall System Structure and Working Principle
,
Using virtual test instruments the Virtual vibration testing and analyzing system completes the work of measuring, data analysis and processing of mechanical vibration signals. Totally resorting to computer software, it successfully achieves the functions of vibration signal acquisition, display, access and processing. The system structure is illustrated in Figure1.
Fig. 1. Schematic diagram of system structure
Hardware for the system includes: acceleration sensor, signal amplifier suitable for transfer, data acquisition card and PC machines. Its software is realized through graphic-oriented software LabVIEW. The seat vibration test and analysis system first transforms the vibration signals detected by the sensor into analog signals, and then passed it to the signal conditioning. Next, the analog electronic signal is converted into digital signal by data acquisition card and finally is passed to the vibration test and analysis computer software for analysis. The system realizes the seat vibration signal testing and data analysis via computer, which can completely replace the conventional signal analyzer and many other hardware devices to complete a variety of signal analysis and processing.
3 Designing of System Functions Based on the needs of seat vibration comfort testing, the main functions of this system include vibration signal acquisition and display, signal analysis and processing, dynamic characteristics analysis and comfort-rating assessment on seat vibration. Block diagram of the system function is shown in Figure 2.
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seat vibration detecting and analyzing system
vibration signal acquisition
dynamic signal analyzing and processing characteristics analysis
comfort rating assessment
Fig. 2. Block diagram of the system function
4 Implementation and Testing of System Functions Front panel of the seat vibration test system is shown in Figure 3, the functional modules can be switched freely through the option cards to achieve the functions of signal acquisition, signal processing, dynamic analysis and evaluation of comfort. 4.1 Vibration Signal Acquisition Module The system completes the external circuit signal acquisition through the DAQ assistant acquisition module and NI ELVIS external board. The acquisition results are shown in Figure 3.
Fig. 3. Front panel of the seat vibration test system
4.2 Signal Analysis and Processing Module In order to eliminate the interference aroused by external signals on the vibration signals, the acquired signals must be pretreated. The system mainly makes some
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filtering and spectrum analysis on analog signals mixed with noise, in order to complete the module test. The mathematics algorithm for filtering is rather complicated, but LabVIEW has modularized the filtering function, so it is quite easy to complete the filtering program with these functions. Signals mixed with noise have been filtered and a comparison between the source signal and the filtered signals will clearly demonstrate the effect as shown in Figure 4.
Fig. 4. Effect of filtering
Besides filtering the signals, the module also has many other functions including frequency domain analysis, window processing, correlation analysis, FFT transform and etc. 4.3 Dynamics Analysis Module The main function of car seats is to support the driver and the passenger's body, to reduce the impact of uneven road surface and to attenuate the resulting vibrations passed to the people, so as to provide a comfortable and safe riding condition. The kinetic parameters --- natural frequency and the damping ratio of the car seat, have a major impact on the damping properties of the seat. Thus, take a representative 1-DOF and 3-DOF occupant-seat model for dynamic analysis. Suggestions on how to choose dynamic parameters are also presented. The structure of 1-DOF and 3-DOF occupant-seat model is shown in figure 5. In 1-DOF model, the human body is considered as a rigid body on the seat. Its frequency response function is: | H (ω ) |=
1 + (2ξγ ) 2 (1 − γ 2 ) 2 + (2ξγ ) 2
(1)
Where: ξ = C /( 2 KM ) is the damping ratio, γ = ω / K / M is the frequency ratio. The seat damping ratio and frequency ratio can be adjusted by changing the parameters of the car seat, so as to improve the frequency response of the seat.
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Fig. 5. Structure of 1-DOF and 3-DOF occupant-seat model
In 3-DOF model, the human body is considered as a 2-DOF dynamic model on the seat. Suppose: ω n = K /( M 1 + M 2 ) , ω n1 = K1 / M 1 , ω n 2 = K 2 / M 2 , γ = ω / ω n ,
γ 1 = ω / ω n1
,
γ 2 = ω / ω n 2 , ξ = C (2 K ( M1 + M 2 )) , ξ1 = C1 (2 K1M 1 ) ,
ξ 2 = C2 (2 K 2 M 2 ) , μ1 = M 1 ( M 1 + M 2 ) , μ2 = M 2 ( M 1 + M 2 ) , The frequency response function is: H (ω ) =
1 + j 2ξγ (1 + j 2ξγ ) − ( μ1 B1 + μ 2 B2 )
,
(2)
1 + j 2ξ 2 γ 2 1 + j 2ξ1γ 1 . B2 = 2 2 1 − γ 1 + j 2ξ1γ 1 1 − γ 2 + j 2ξ 2γ 2 When analyzing the simulation in LabVIEW, the parameters in the model are set on the following basis: 1) “Test Method of Car Seat Dynamic Comfort", in which the standard is M = 51kg ; 2) statistic results from domestic human body vibration test, in which M1 = 29.8kg, M2 = 5.5kg, K1 = 224.8N/cm, K2 = 133.1N/cm, C1 = 3.9N / (cm.s), C1 = 1.9N / (cm.s). The frequency response function of the two models is related not only to the parameters of the human body model but also to the natural frequency and damping ratio of the seat. Figure 6 shows the system frequency response curve under different natural frequency and damping ratio of 1-DOF model, by which reasonable parameters can be chosen. Where: B1 =
Fig. 6. Frequency response curve under different damping ratio and natural frequency
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The module can also analyze the displacement response curve of human body vibration by simulating different car environment and road condition. When different seat parameters are selected, the changes of human body vibration displacement can be directly observed, which will provide favorable reference for the design of safe and comfortable seats. 4.4 Seat Comfort Assessment Module The function of data analysis module is to analyze the collected and pretreated signals, so that the specific values of comfort can be obtained and car seat comfort can be measured. Data is processed using total RMS value of weighted acceleration comparison method by the data analysis module. Taking into account individual’s different sensitivity to the frequency of vibration, this method converts RMS acceleration which frequency ranges within 1 ~ 80Hz into RMS acceleration within sensitive frequency (4 ~ 8Hz, or 1 ~ 2Hz) by multiplying a different frequency weighting, then calculates the total acceleration RMS, and then sets the standard for evaluation: whether the corresponding limit exceeds ISO2631 sensitivity limit of the frequency or length of time. As for the composite vibration condition which human body withstand from X, Y, Z three directions, we can first obtain respective frequency weighted RMS by calculating the acceleration spectra in each vibration direction, and then calculate the combined weighted acceleration value Aω.
Aω = (1.4axω ) 2 + (1.4a yω ) 2 + (azω ) 2
(3)
Where: the factor of 1.4 is the most sensitive in the body within the same frequency range corresponding vertical and horizontal and vertical curve ratio. "Total Travel Value Method" has been introduced in the draft of ISO2631/CD1991, and the relationship between the acceleration value and the subjective feeling of the occupant has been given, as is shown in Table 1. Table 1. Relationship between Acceleration Value and Subjective Feeling of the Occupant
(m/s )
Weighted Acceleration Value <0.0315 0.315 0.63 0.5 1.0 0.8 1.6 1.25 2.5 >2.0
~ ~ ~ ~
2
Subjective Feeling of the Occupant Comfortable slightly uncomfortable somewhat uncomfortable Uncomfortable very uncomfortable Unbearably Uncomfortable
The vibration signals from X, Y and Z direction are measured by the sensor. Then they are converted into vehicle vibration comfort indicators Cω and combined weighted RMS Aω through the program operation. Finally, the comfort condition is displayed on the front panel.
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5 Conclusion This system is actualized through a powerful graphical programming language LabVIEW and the existing hardware devices. It can measure seat vibration, process data, analyze seat dynamics characteristic and evaluate the driving comfort. Compared with traditional method, this system has the following advantages: (1) Computer software program has replaced the traditional spectrum analyzers and other hardware devices. This system validates real-time analysis and processing, reduces test costs and shortens the test cycle. (2) Resorting to the existing signal processing modules of LabVIEW to deal with vibration signals, the process is quicker and more accurate, and thus complex mathematic calculation is avoided. (3) By making a dynamic simulation analysis on the human body - seat model, it provides a favorable reference to the designing of safe and comfortable seats. Based on ISO2631 standard, seat driving comfort is also evaluated. Acknowledgement. This work is supported by the Research Foundation of ECJTU (NO. 01308115), and Key Laboratory of Conveyance and Equipment.
References 1. Boileau, P. E.: A body Mass Dependent Mechanical Impendence Model for Application in vibration Seat Testing. J. Journal of Sound and Vibration 253(1), 243–264 (2002) 2. National Instruments Corp LabVIEW User Manual, Austin, Texas, USA, pp. 27–444 (1998) 3. National Instruments Corp BridgeVIEW and LabVIEW G Programming Reference Manual, Austin, Texas USA, pp. 27–566 (1998) 4. Dai, X., Sun, H., Ou, J.J.: Virtual instrument design for mechanical vibration measurement. In Chinese. China Measurement & Testing Technology 34(4), 92–95 (2008) 5. Meng, Y.M., Gao, F.W., Duan, J.L., Li, S.P., Huang, B.P.: The research of vibration measurement and analysis system based on LABVIEW. in Chinese. Journal of Guangxi University (Nat. Sci. Ed.) 32(2), 114–117 (2007) 6. Qian, Y., Zhou, Y.P., Chen, J.W.: Analytical System of Vibration Measurement Based on LabVIEW. In Chinese. Journal of Wenzhou University, 58–61 (2005) 7. Chen, X.W., Liu, Y.: Realization of test analysis for vibration signal based on LabVIEW. In Chinese. Electronic Measurement Technology, 108–120 (2008)
Determination of Pesticide Residues on the Surface of Fruits Using Micro-Raman Spectroscopy Yande Liu1,2 and Tao Liu1 1
School of Mechanical and Electronical Engineering, East China Jiaotong University, Nanchang, China 2 Institute of Optics-Mechanics-Electronics Technology and Application (OMETA), East China Jiaotong University, Nanchang, China
Abstract. A simple, rapid and environmentally friendly method was developed for micro-Raman spectroscopy determination of pesticide residues on the surface of fruits. Raman spectra of fruits, pesticides and pericarps sprayed by pesticide solutions were acquired using a laser power of 14 mW at excitation wavelength of 780 nm. From the Raman spectra, the residual pesticides could be distinguished and determined through the characteristic Raman peaks. The overall results indicted that micro-Raman spectroscopy is a potential tool to determine the pesticide residues on the surface of fruits for fruit quality and safety control. Keywords: micro-Raman spectroscopy, fruit, pesticide residue.
1 Introduction Pesticides are defined by the United Nations Food and Agricultural Organization (FAO) as substances or mixtures intended to prevent, destroy, repel or mitigate any pest, including insects, rodents and weeds [1]. Currently, pesticides play a critical role in protecting fruit crops. However, large amount of pesticides are used in fruits production making it unsafe and endangering humans and animals. One of the most common used pesticides are the organophosphates, which kill insects and mites by attacking the central nervous system, and consequently pose a threat to human beings and animal lives [2]. Nowadays, fruit safety and quality has been attracted more and more attention. In many countries, strict tolerance levels are set up to ensure public safety. The current analysis methods for determining the residual pesticides in fresh fruits are based on chemical analysis, such as liquid chromatography-mass spectrometry (LC-MS) [3], liquid chromatography-tandem mass spectrometry (LC-MS/MS) [4, 5], gas chromatography-mass spectrometry (GC-MS) [6], capillary electrophoresis-mass spectrometry (CE-MS) [7] and ultra-high-performance liquid chromatography (UHPLC) [8], etc. However, all of the methods mentioned above are time-consuming, not environmentally friendly and inconvenient enough for the process of sample preparation. Hence, it was very necessary to develop a simple, rapid and low cost method for the determination of pesticide residuals in fruits. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 427–434, 2011. © IFIP International Federation for Information Processing 2011
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Raman spectroscopy is a fast technique compared to classical chromatography. It is a powerful analytical tool that provides wonderful advantages including non-destructive, low cost and ultrasensitive characterization down to single molecular level [9]. Shende et al. [10] used surface-enhanced Raman spectroscopy (SERS) to analyze pesticides on fruit surfaces. Zhou et al. [11] recorded several spectra of fruits with pesticides using near infrared Fourier transform Raman spectroscopy (FT-Raman). Several Raman spectra of some fruits and pesticides on the surface of fruits were acquired and compared with at two excitation wavelengths of 514.5 and 1064 nm by Zhang et al. [12]. Micro-Raman has its unique characters compared to other Raman techniques, since it allows analysis of materials with a spatial resolution of several microns focused by an optical microscope. It has been developed for a rapid, environmentally friendly and low cost generation procedure, and has been applied in many fields, such as gems [13, 14], fibers [15, 16] and geology [17, 18], etc. In this paper, a new attempt to determine the residual pesticides on the surface of fruits using micro-Raman spectroscopy was reported. The objective was to record the Raman spectra of fruits and pesticides in order to study the feasibility of using micro-Raman spectroscopy to determine the residual pesticides on the surface of fruits.
2 Materials and Methods 2.1 Apparatus A Nicolet DXR Raman Microscope (Thermo Fisher Scientific Corp., Madison, WI, USA), equipped with a liquid nitrogen cooled CCD detector and a 14 mW maximum power diode laser, that emits at 780 nm, was employed for confocal micro-Raman spectra acquisition using 2 ml standard glass chromatographic vials (12 mm×32 mm) as sample cells. The laser was focused within the sample using an inverted microscope setup equipped with a 10× ultra long working distance objective. The scattered signal was then recorded at a 180° backscattering geometry and dispersed by a single monochromator using a 400 grooves/mm diffraction grating and a laser line filter used as a beam splitter to lead the laser beam into the microscope assembly and also to reject the Rayleigh scattered light on the returning path. Spectrometer was controlled with OMINIC software (Thermo Nicolet Corp., Madison, WI, USA). 2.2 Sample Preparation and Chemicals The samples, including apples, pears and oranges fruits in the experiment, were purchased directly from the Nanchang fruit market. The chemicals, dimethoate standard (O,O-dimethyl- S-(N-methylcarbomoylmethyl) phosphorodithioate) solid (99.1% w/v), chlorpyrifos standard (O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) solid (99.5% w/v) and malathion standard (S-(1,2-dicarbethoxyethyl)-O,O-dimethyl dithiophosphate) solution (99.1% w/v) were purchased from bzwz corporation (Beijing, China). Two emulsifiable concentrate commercial pesticide formulations, chlorpyrifos (40% w/w) and malathion (40% w/w) were obtained directly from the Nanchang pesticide market. Before recording the micro-Raman spectra, all the fruits were cleaned carefully. Firstly, fruits were flushed several times with fresh water to get rid of the dirt left on the
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surface, and then wiped with cotton and alcohol. After that, small pieces of pericarps from the cleaned fruits were taken off, and then sprayed by a little amount of pesticide formulations. At last, filter papers were used to wipe off any left over pesticides from the pericarps, and let the samples dry naturally. 2.3 Micro-Raman Procedure When it was time to record the micro-Raman spectra, the resolution and accumulating time were fixed at 1.93 cm-1 and 100 scans per spectrum. The micro-Raman spectra of clean pericarps of apples, pears, oranges and four standard pesticides were collected, firstly. These spectra were used as standards in the comparison database. Then the spectra of pericarps sprayed by the pesticide formulations were collected and compared with those in the database to identify the trace amount of pesticides on the surface of fruits. All the spectra mentioned above were carried out in chromatographic glass vials from 3390 to 110 cm-1 with the diode laser power employed fixed at 14 mW.
3 Results and Discussion 3.1 Raman Spectra of Fruits
1005
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From the three figures mentioned above, each of pesticides could be distinguished using their characteristic peaks shown in Table 1. These bands could be employed for determining pesticide residues on the surface of fruits. Table 1. Characteristic peaks of chlorpyrifos, dimethoate and malathion Pesticide Chlorpyrifos Dimethoate Malathion
Characteristic peaks (cm-1) 1569, 1276, 676, 630, 340 1640, 651, 494 1733, 1451, 652
3.3 Raman Spectra of Pesticide Residues on the Surface of Fruits Acquirements of Raman spectra of fruits with pesticides were performed with the same measuring conditions as before. Fig. 5 and Fig. 6 show the Raman spectra of chlorpyrifos and malathion formulations residues on the surface of oranges. From Fig. 5, it can be obviously seen that the spectrum of chlorpyrifos residue on the surface of orange not only contains the strong peaks of orange itself, but also contains the characteristic modes of chlorpyrifos which located at 676, 630 and 340 cm-1. Similarly, in Fig. 6, the characteristic modes of malathion at 1451, 859, 652 and 496 cm-1 can be seen in the spectrum of its residue on the surface of orange. Based on the results, it was concluded that the method of using micro-Raman spectroscopy could be utilized for automatic and intelligent determination of the pesticide residues on the surface of fruits.
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4 Conclusions The micro-Raman spectra of apples, pears, oranges, several pesticides and pesticide residues on the surface of oranges were successfully recorded using a micro-Raman spectrometer. The characteristic peaks of pesticides can be seen from the spectra of pesticides left on the surface of fruits. Micro-Raman spectroscopy is a potential tool to determine the pesticide residues for fruit quality and safety control with rapid, non-destructive, low cost and environmentally friendly advantages.
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Acknowledgements The authors gratefully acknowledge the financial support provided by National Science and Technology Support Program (2008BAD96B04), Natural Science Foundation of Jiangxi Province (2008GQN0029, 2007GZN0266), Special Science and Technology-Support Program for Foreign Science and Technology Cooperation Plan (2009BHB15200), Technological expertise and academic leaders training program of Jiangxi Province (2009DD00700).
References 1. UN Food and Agricultural Organization: International Code of Conduct on the Distribution and Use of Pesticides, Rome, Italy (2002) 2. Tuormaa, T.E.: Adverse Effects of Agrochemicals on Reproduction and Health: a Brief Review from the Literature. J. Nutritional Environ. Med. 5, 353–366 (1995) 3. Picó, Y., Font, G., Moltó, J.C., Mañes, J.: Pesticide Residue Determination in Fruit and Vegetables by Liquid Chromatography–mass Spectrometry. J. Chromatogr. A 882, 153–173 (2000) 4. Jansson, C., Pihlström, T., Österdahl, B., Markides, K.E.: A New Multi-residue Method for Analysis of Pesticide Residues in Fruit and Vegetables Using Liquid Chromatography with Tandem Mass Spectrometric Detection. J. Chromatogr. A 1023, 93–104 (2004) 5. Frenich, A.G., Vidal, J.L.M., López, T.L., Aguado, S.C., Salvador, I.M.: Monitoring Multi-class Pesticide Residues in Fresh Fruits and Vegetables by Liquid Chromatography with Tandem Mass Spectrometry. J. Chromatogr. A 1048, 199–206 (2004) 6. Guan, H.X., Brewer, W.E., Garris, S.T., Morgan, S.L.: Disposable Pipette Extraction for the Analysis of Pesticides in Fruit and Vegetables Using Gas Chromatography/Mass Spectrometry. J. Chromatogr. A 1217, 1867–1874 (2010) 7. Juan-García, A., Font, G., Juan, C., Picó, Y.: Pressurised Liquid Extraction and Capillary Electrophoresis–mass Spectrometry for the Analysis of Pesticide Residues in Fruits from Valencian Markets, Spain. Food Chem. 120, 1242–1249 (2010) 8. Lacina, O., Urbanova, J., Poustka, J., Hajslova, J.: Identification/Quantification of Multiple Pesticide Residues in Food Plants by Ultra-high-performance Liquid Chromatography-time-of-flight Mass Spectrometry. J. Chromatogr. A 1217, 648–659 (2010) 9. Armenta, S., Quintás, G., Garrigues, S., de la Guardia, M.: Mid-infrared and Raman Spectrometry for Quality Control of Pesticide Formulations. Trends Anal. Chem. 24, 772–781 (2005) 10. Shende, C.S., Inscore, F., Gift, A., Maksymiuk, P., Farquharson, S.: Analysis of Pesticides on or in Fruit by Surface-enhanced Raman Spectroscopy. In: Proc. SPIE, vol. 5587, pp. 170–176 (2004) 11. Zhou, X.F., Fang, Y., Zhang, P.X.: Raman Spectra of Pesticides on the Surface of Fruits. J. Light Scatt. 16, 11–14 (2004) 12. Zhang, P.X., Zhou, X.F., Cheng, A.Y.S., Fang, Y.: Raman Spectra from Pesticides on the Surface of Fruits. J. Phys. 28, 7–11 (2006) 13. Sudheer, S.K., Pillai, V.P.M., Nayar, V.U.: Characterization of Laser Processing of Single-crystal Natural Diamonds Using Micro-Raman Spectroscopic Investigations. J. of Raman Spectrosc. 38, 427–435 (2007)
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14. Palanza, V., Martino, D.D., Paleari, A., Spinolo, G., Prosperi, L.: Micro-Raman Spectroscopy Applied to the Study of Inclusions within Sapphire. J. Raman Spectrosc. 39, 1007–1011 (2008) 15. Doherty, B., Miliani, C., Berghe, I.V., Sgamellotti, A., Brunetti, B.G.: Micro-Raman Spectroscopic Study of Artificially Aged Natural and Dyed Wool. J. Raman Spectrosc. 39, 638–645 (2008) 16. Colomban, P., Dinh, H.M., Riand, J., Prinsloo, L.C., Mauchamp, B.: Nanomechanics of Single Silkworm and Spider Fibres: a Raman and Micro-mechanical in Situ Study of the Conformation Change with Stress. J. Raman Spectrosc. 39, 1749–1764 (2008) 17. Rull, F., Martinez-Frias, J., Sansano, A., Medina, J., Edwards, H.G.M.: Comparative Micro-Raman Study of the Nakhla and Vaca Muerta Meteorites. J. Raman Spectrosc. 35, 497–503 (2004) 18. Łodziński, M., Wrzalik, R., Sitarz, M.: Micro-Raman Spectroscopy Studies of Some Accessory Minerals from Pegmatites of the Sowie Mts and Strzegom-Sobótka Massif, Lower Silesia, Poland. J. Mol. Struct., 744–747, 1017–1026 (2005) 19. El-Abassy, R.M., Donfack, P., Materny, A.: Rapid Determination of Free Fatty Acid in Extra Virgin Olive Oil by Raman Spectroscopy and Multivariate Analysis. J. Am. Oil Chem. Soc. 86, 507–511 (2009) 20. Skoulika, S.G., Georgiou, C.A., Polissiou, M.G.: FT-Raman Spectroscopy—Analytical Tool for Routine Analysis of Diazinon Pesticide Formulations. Talanta 51, 599–604 (2000) 21. Quintás, G., Garrigues, S., de la Guardia, M.: FT–Raman Spectrometry Determination of Malathion in Pesticide Formulations. Talanta 63, 345–350 (2004)
Development of the Meter for Measuring Pork Quality Based on the Electrical Characteristics* Zhen Xing1, Wengang Zheng2, Changjun Shen1,2, and Xin Zhang1,2 1
Beijing Research Center for Intelligent Agricultural Equipment, 100097, Beijing, China 2 National Engineering Research Center for Information Technology in Agriculture, 100097, Beijing, China {xingz,zhengwg,shencj,zhangx}@nercita.org.cn
Abstract. The excitation frequency on the electrical characteristics of pork had been identified by the experiments of the electrical characteristics and the theory of electrical characteristics, the relationship between the evaluation of quality of pork and the impedance characteristics was established, and a nondestructive portable meter for measuring pork quality was developed. The functions of each hardware and software design of the meter were described in detail. The result shows that the conductivity of the pork increases with the level of corruption by the experiment of the measurement selected sample of pork. The pork quality meter based on the electrical characteristics provides the measurement method and apparatus of a low-cost, rapid, qualitative assessment of pork quality. Keywords: the electrical characteristics, pork quality, a portable meter, a lowcost.
1 Introduction Food safety become the focus of attention when people’s living standard have been rising, The meat is the main food in china; China is one of the biggest countries for the production of livestock and poultry meat and its products. According to The People's Republic of China Statistical Yearbook 2008, China's pork production in 2007 was 42.878 million tons, the amount of production and consumption all ranks the world. People are cautious about meat consumption when meat safety incidents, such as, the injection meat or the clenbuterol, are frequently exposed [1]. In order to eliminate consumer concern for meat product, some approaches should be taken, such as, improving the moral quality of the farmers and producers, and preventing non-healthy meat to target into the market. So the measuring meter for fast detection of meat quality is an important role in the quarantine before meat onto the market. *
The paper was supported by the National High Technology Research and Development Program("863"Program) of China (2007AA10 Z212).
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Currently, there are a lot of pork quality detection methods. For example, the fat of the pig ketene body and the lean meat were graded by using spectroscopy or ultrasonic detection in the abroad; the nutritional composition in meat and meat quality changes are studied by using the equipment of near-infrared spectroscopy or the chemo metrics in the domestic; the study group of Ding[2] had been studied the nondestructive optical detection methods for the fatty tissue, and measured the content of the Hemoglobin and the myoglobin in different depths of muscle; the study group of Huang [3,4] had been studied the optical parameter properties of agricultural products, the detection of fresh pork and deep water of the fresh pork. In addition, the meat quality of detection methods, based on dielectric properties or electrochemical properties, had been developed rapidly. For example, Zhang [5] had been studied temperature effect on the dielectric properties of the lunch pork roll; Kent [6] soaked the meat in water at different times, attained different the water content, and studied the water content effect on the dielectric properties of chicken, scallops and pork. Zhang [7] had been studied the salt effect on the permittivity and dielectric loss factor of the pork. Currently, the dielectric properties of the raw meat and meat products had been studied in abroad, especially the microwave dielectric properties, however, detecting the quality of pork by using the dielectric properties has only begun in the domestic. A new sensor based on the transmission line impedance theory was designed by using the coaxial transmission line technology, and the meter for the meter for measuring pork quality based on this new sensor was developed in this paper; it can be more convenient, fast and efficient measurement of pork quality, and ensure the safety of the pork quality.
2 Sensor Design The sensor consists of a power supply unit, a high-frequency signal source, a signal processing unit, a coaxial transmission line and measuring probes. The structure is as shown in Figure 1.
Power unit
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Output Fig. 1. The principle structure of the sensor
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2.1 Measuring Principle Coaxial transmission line measurement technique is that the electrical characteristics of biological tissue (such as conductivity, dielectric constant, etc.) was transferred into high-frequency electromagnetic wave reflection coefficient, the relationship between the electrical characteristics of biological tissue and high frequency electromagnetic wave reflection coefficient, the electrical characteristics of biological tissue can be obtained by measuring the radiation coefficient. When the power supply was at work, a fixed-and high-frequency signal, generated by the crystal oscillator, transmitted through the coaxial transmission line to the probe which was inserted into the testing material. Due to the impedance’s mismatching, parts of the signals would return and superpose with the latter input ones. Consequently, it set up a doable way of associating a stabilized amplitude voltage with the coaxial transmission line and the probe, which is available to the quality detecting. 2.2 Signal Processing Circuit According to signal detection theory, the signal processing circuit of accuracy, stability, sensitivity directly determines the overall system performance, therefore, the design of the signal processing circuit is crucial, it must eliminate noise and amplify useful signal. Aiming at catering to this need, the measurement circuit can be simplified as two-stage amplification. The signal processing circuit is shown in detail in Figure 2.
Fig. 2. Block diagram of signal processing circuit
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Observing that the first-stage used difference amplifier to perform differential operation, and the input sinusoidal signal was changed into DC signal, the function of the current-conveyor was to ensure the working probe is held at virtual ground when it was connected at the impedance. In addition, difference amplifier has the advantage of eliminating the Zero Drift. The second-stage amplifier was simply to give rise to the former-step’s output signal, which aimed at improving stability of the testing system. The parameters of every component are as follows.
3 System Architecture The system architecture is shown in the figure 3. The low-power MCU MSP430F149 is used as the core of the system acquisition and control, its power consumption and input leakage current (up to 50nA) is relatively low in the industry, the MSP430F149 is an industrial grade product, stable performance, high reliability. There are many work modes of the MSP430F149; the system power consumption is reduced by selecting a low power operating mode, so the MSP430F149 is especially suitable for handheld applications. It can reduce the number of external components and the cost of the instrument because of its 12-bit A / D converter. The keyboard and LCD modules for the operator provide a friendly human-machine interface; the real-time clock module can record the system running time; the memory module can save operating parameters and measurement data; the sensor interface is using a convenient PS / 2 interface.
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3.1 The Power Module The meter is using two 1.5V batteries or a rechargeable battery, but the number of external components and the MSP430F149 must work at 3.3V, so it must increase the value of the power module. The circuit of the increasing voltage is shown in the figure 4. The chip of MAX1724, which character is a low quiescent current and high efficiency, is used in the power module.
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Fig. 4. The schematic of power
3.2 The RTC Module The RTC module is designed for ensuring the system time synchronization, the schematic of the RTC is shown in the figure 5. The PCF8563 is a CMOS Real-Time Clock and calendar optimized for low power consumption. A programmable clock output, interrupt output, and voltage-low detector are also provided.
Fig. 5. The schematic of the RTC
3.3 The Memory Module The 24LC02B is organized as one block of 256 X 8-bit memory with a 2-wire serial interface. Low-voltage design permits operation down to 2.5V, with standby and active currents of only 1 μA and 1 mA, respectively. its feature is low power consumption, simple external circuit, and write protection. The principle circuit of the
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memory module is shown in the figure 6. The pins of A0, A1, and A2 connect to the ground, its address is 000, and the pin of the WP connects to the ground, so the chip can be all written. The pins of the SCL and the SDA connect respectively 10K resistor, and make the level of the SCL and the SDA high, so can conveniently read and write.
Fig. 6. The circuit of the memory module
4 System Software Design The system software is modular in design, and they include a data measurement and processing module, a data storage module, a serial interface module, a keyboard and a LCD module, and act. The events are handled at the before platform and backstage. When the system is power on, initializes kinds of parameters, and then enters into the waiting stage; when receiving the measurement command, the system begins to measure, process, and storage the data.
5 Experiment and Discussion 5.1 Experiment Analysis The test material was obtained from swine fillet and qualified by the quarantine system. The raw meat was fed to the meat grinder by inches to chop into fillet emulsion specimen, which were uniform in composition, within five times’ wring. Using the electronic balance divided the emulsion into 10g per portion by weight. Being intended to optimize the quality of test sample, delicately adding the demonized water into it until well-mixed was suggested. Afterwards, semi finished products were placed in the experimental beaker to prepare emulsion-aqueous solution of 10% and 20% respectively.
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Fig. 7. Sensor output voltages within distinguished water-addition samples
The curvilinear was shown in Figure 7, the points of each group fluctuated around a certain value. With different water content added, the output results varied from one sample to another. Apparently, the more water it contained, the higher output voltage it may afterward lead to, and vice versa. Taking the 10%-water-addition sample for an instance, we got the average of 3.10 and standard deviation of 0.01457 by calculating. The value was 0.47%, which indicated a low dispersion degree. Similarly, that of the 20%-water-addition sample was 0.49%. So we dare to say, with the same testing sample, different sensors independently applied have obtained tolerably similar results, whose service performance and effectiveness can meet the need of measuring. 5.2 Discussions Based on the research of the coaxial transmission line theory, the sensor and the meter for measuring pork quality were designed. The measurement results show that the stability and consistency of the sensor meet measurement requirements. The plan of a low-power, battery-powered portable meter is designed. The characters of the MSP430F149 are low power consumption and real-time wake-up function, so the power consumption of the measuring meter of pork quality is rather lower, and this feature is ideal for portable meter. A friendly human-machine interface and standard PS/2 interface are very convenient for users. In addition, the pork quality includes food quality, nutritional quality, technical quality, health quality and human quality, etc. At present, the quality of pork was inspected mainly through PH value, odor, color and the content of the water, the detection methods of using the PH value, odor, color were not in time in measuring the pork quality. The content of the water in the pork impacted on the pork quality was only considered in this paper; other parameters were ignored in this paper. If the pork quality was comprehensive responded, we must considered other factors, such as the PH value, odor, color, act. So the system of the pork quality evaluation is not put forward, and requires further study.
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References 1. Goldenberg, A.A., Lu, Z.: Automation of meat pork grading process. J. Computers and Electronics in Agriculture. 16(2), 125–135 (1997) 2. Ding, H., Duan, Y., He, T.: Spectral Research On The Effect of Optical Propa Gation in The Fat. J. Spectroscopy and Spectral Analysis 15(6), 19–24 (1995) 3. Ji, R., Wang, Z., Huang, L., et al.: Study of Measurement Methods for Detecting the Water Content in Deep Layer of Fresh Meat. J. Modern Scientific Instruments 1, 119–121 (2006) 4. Ding, Q., Wang, Z., Huang, L., et al.: Development of portable bio-impedance spectroscopy system for measuring porcine meat quality. J. Transactions of the CSAE 12(25), 138–144 (2009) 5. Zhang, L., Lyng, J.G., Brunton, N., et al.: Dielectric and thermo physical properties of meat batters over a temperature range of 5-85 . J. Meat Science 68(2), 173–184 (2004) 6. Kent, M., Peymann, A., Gabriel, C., et al.: Determination of added water in pork products using microwave dielectric spectroscopy. J. Food Control 13(3), 143–149 (2002) 7. Zhang, L., Lyng, J.G., Brunton, N.P.: The effect of fat, water and salt on the thermal and dielectric properties of meat batter and its temperature following microwave or radio frequency heating. J. Journal of Food Engineering 80, 142–151 (2007)
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Experimental Investigation of Influence on Non-destructive Testing by Form of Eddy Current Sensor Probe Fengyun Xie* and Jihui Zhou School of Mechanical and Electronical Engineering, East China Jiaotong University, Nanchang 330013, China [email protected]
Abstract. Eddy current testing is a kind of non-destructive testing (NDT) method based on the principle of electromagnetic induction. The probe is the key of eddy current non-destructive inspection and its design or combination of form will influence detectability. A complete set of eddy current testing system is designed for standard testing copper and defect copper. Under the same liftoff distance and the same high frequency excitation signal, designed three types of probe, which are single probe single coil, single probe double coil and double probe double coil, are used to carry out NDT experiment. Experimental results show that sensitivity and resolution of detection system are obvious difference among the different form of eddy current sensor probe. Probe shape and coil winding are improved according to the experimental results. Corresponding improved probe is adopted to carry out NDT experiment at the same condition. Experimental results show that detectability is enhanced significantly. Keywords: Eddy current testing, Probe, Non-destructive testing (NDT), Sensitivity.
1 Introduction Eddy current testing based on the principle of electromagnetic induction is a kind of NDT method for testing metal semi-finished and metal components. It has been more and more widely used for its no need touch, high-speed of testing, easy automation, suitable for online testing and high detection sensitivity of surface defect. For example, YANG1et al, considered identification of corrosion fringe in pulsed eddy current non-destructive testing, He2 et al, considered pulsed eddy current technique for defect detection in aircraft riveted structures. However, the form of sensor probe has a great influence on the detection performance. In recent years, it is a research focus of many scholars how to improve the sensitivity of eddy current probes. But the discussion only is in the influence of one aspect, rather than the system. For example, Ren3 et al, proposed to increase the probe diameter or adapt big pie-type probe to improve the detection sensitivity, but it will reduce detection sensitivity of small defects. Kim4 et al, considered a dual-electromagnetic sensor *
Corresponding author. Tel.: 0086-791-7046135; Fax: 0086-791-7046122.
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system for weld seam tracking of I-butt joints. Li5 et al, analyzed detection principle and influence factors of eddy current. Yu6 et al, designed a novel pulsed eddy current testing probe based on 3D magnetic field measurement. Gao7 et al, studied on structure optimization of eddy current probe, and obtained three influence factors on eddy current sensitivity: exciting coil of eddy current is stronger than slot width, and slot width is stronger than detection coil of eddy current. In this paper, we summarize the previous discussion, full unscramble measurement principle of eddy current. The procedure is: to design a placed device of eddy current testing; to use different forms of probe to carry out comparative test to the standard copper and defect copper. The specific objectives are: to get the relations between probe form and sensitivity of NDT; to put forward recommendations for improvement of the probe.
2 Testing Principle and Methods of Eddy Current Eddy current testing is a kind of NDT method based on the principle of electromagnetic induction, which is applied to conductive materials. Testing principle is the following: the signal generator provides high frequency alternating current to the probe in the detection coil, detection coil produces an alternating magnetic field, and the specimen produces eddy current. Eddy current is affected by the properties of the specimen, and in turn it changes impedance (voltage) of coil, then oscilloscope output impedance (voltage) of coil. Testing process includes picked up signal, signal amplification, signal processing, eliminated interference signal, and display and record test results. There are two kinds of detection methods. One is a double-coil high frequency reflection, whose schematic diagram is shown in Fig. 1.it has a high detection sensitivity of surface defect, but it is lower defect sensitivity with deeper below the surface; The other is double-coil low frequency transmission, whose schematic diagram is shown in Fig. 2.
Fig. 1. Schematic diagram of low frequency reflection
Fig. 2. Schematic diagram of high frequency transmission
Two methods have the same testing process. Signal generator produced alternating current flows through the coil, when the probe moves to the specimen, the eddy current will decrease. Impedance of the coil is displayed and recorded by the meter.
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Using auxiliary equipment to do comparative analysis of results from Standard specimens and defect specimens can obtain NDT results.
3 Theoretical Basis for Experimental Study The workpiece signal of detected is from impedance of the detection coil or the induced voltage changes of secondary coil in eddy current testing. We use long straight solenoid of cylindrical conductor as the object of research, suppose the radius of cylindrical conductor as a less than the solenoid inner radius b, and suppose turns of per unit length as n. In the cylindrical conductor (0
Φ = μ 0 μ r μ eff H 0 π a 2 + μ 0 H 0 π ( b 2 − a 2 ).
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.
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.
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4 Eddy Current Testing Scheme According the principle of eddy current testing, the scheme is shown in Fig. 3. Signal Generator issues high frequency alternating signal to the detection probe, taking Signal Generator into account impedance of the exciting coil and Detection probe detection coil may not be equal. We use a balanced circuit to eliminate the voltage differPreamplifier, Phase sensitive detection ence between the two coils in pre-test. In the detection, the detection coil to detect Balance filter defective parts will produce a slight and imbalDigital phase rotation ance signal. After amplification, phase sensitive detection, filter, and removed the interfeAdjustable gain amplifier rence signal will turn into the DC signal which A/D contains phase and amplitude characteristics of impedance (voltage) of coil, at last displayed Computer system and recorded by display device. According to records of the results, we draw Display the normalized sensitivity curves with the liftoff change, put forward recommendations for Fig. 3. Eddy current testing scheme improvement of probe the form and carry out improvement by analyzing the curves. At the same time, we draw the normalized sensitivity curves with the lift-off change, and draw final test conclusions.
5 NDT Experimental Study 5.1 Test Preparation In accordance with the testing program, preparing experimental apparatus, the main instruments include a high frequency signal generator, an oscilloscope, a standard copper, a defect copper whose depth of defect size is 2mm, and length of defect size is 12mm, multiple probes which have a single probe self-inductance coil (1000 turns), a single probe mutual inductance coil (500 turns each), two double probe transmission coils (500 turns).To make the coil diameter of probe is 8mm and 10mm, thickness is 4mm and 6mm. 5.2 Test Procedure Test procedure is to build test equipment in accordance with testing program. We regulate output frequency of high-frequency signal generator as 4KHz, adjust lift-off distance of excitation coil and detection coil respectively as 0mm, 1mm, 2mm, 3mm, 4mm, 5mm. Using different forms probe test standard copper and defect copper, output voltage peak – peak value by oscilloscope, we draw the normalized sensitivity curves of the different probe forms with the lift-off change, Abscissa for the lift-off distance and ordinate for the normalized signal amplitude of specimens. Curves are the results of different probe forms including single probe self-inductance, single
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probe mutual inductance, double probe transmission, double probe reflection, double probe in series and in parallel. Output voltage peak-peak value of can be obtained form the display device. 5.3 Influence of Detection Sensitivity by Different Probe Forms Fig. 4 and 5 are the normalized sensitivity curves with the lift-off change to initial test standard copper and defect copper. Curve 1 is the result of oscilloscope by directly connecting to signal generator, curve 2 is the detective result of the single probe, curve 3 is the result of the double probe in series, curve 4 is the no-load result of the double-probe, curve 5 is the result of double probe reflection, curve 6 is the detective result of the double probe transmission.
Fig. 4. Standard copper sensitivity curves with the lift-off
Fig. 5. Defect copper sensitivity curves with the lift-off
5.4 Influence of Impedance (Voltage) by Probe Diameter Under the 4KHz high-frequency alternating signal generator, we change the probe diameter. Fig. 6 shows the influence of probe diameter, with the probe diameter increasing, the impedance moves down along the curves, as the coil diameter increases, the detection sensitivity decreases. 1 1.0
2 4
Normalized impedance
0.9 0.8
8
0.7 0.6
L ift-off
D mm 16
0.5 0.4
32
0 N orm alized im pedance
Fig. 6. Influence of impedance by probe diameter
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5.5 Improved Probe Test Analyzing initial test results can obtain that probe size, coil thickness and coil turns closely related test results. Improved probe is the following : arranged the copper wire of probe as far as possible orderly, enhanced the magnetic flux density of the surface, increased the probe turns by 100 turns, changed the probe diameter for 8mm and thickness for 4mm. Using the improved appropriate probe include single probe selfinductance, single probe mutual inductance , double probe transmission, double-probe reflection , double-probe in series and in parallel to carry out NDT and experimental analysis, and draw sensitivity curves of Fig. 7 and 8.
Fig. 7. Standard copper sensitivity curves of improved probe with the lift-off
Fig. 8. Defect copper sensitivity curves of improved probe with the lift-off
5.6 Results and Discussion We contrast sensitivity curve of before and after Probe improved. 1) Sensitivity curve 1 to 3 almost has no change under small lift-off distance. Curve 1 is the result of oscilloscope by directly connecting to signal generator, curve 2 is the detective result of the single probe, curve 1 and curve 2 almost coincide, it shows little effect on the output changes by single probe self-inductance. Curve 3 is the result of the double probe in series, curve 1 and curve 3 almost coincide, it shows the probe in series with different the number of turns, if equal of turns add, the results have no change. 2) Sensitivity curve 4 to 6 changes significantly, sensitivity of double-probe transmission no specimen is higher than the existing specimen, minimum sensitivity is double-probe reflection. 3) Detective sensitivity of standard copper is higher than defect copper. With liftoff distance increasing, sensitivity decreases rapidly, for example, Fig. 5 shows the defect signal amplitude down to the 1/ 4 of the surface when curve 6 lift-off for the 1mm. 4) Comparing Fig. 4 and Fig. 7, Fig. 5 and Fig. 8, the sensitivity of improved probe is significantly higher than before improvement. 5) Probe diameter significant has influence on the detection sensitivity, with the coil diameter increasing, the detection sensitivity decreases. As diameter of the probe coil increases, the magnetic flux density of workpiece increases, the eddy current value increases, then the equivalent resistance decreases.
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6 Conclusion Eddy current NDT is high sensitivity for detecting defects of conductor surface and near surface, by comparison of the test, the following are concluding summaries: 1) The different probe forms have a significant influence on the ability of eddy current testing. Detectability of double probe transmission is greater than detectability of double probe reflection, detectability of double-probe is greater than detectability of single probe. The coil in series, detectability will be no change if equal of turns add. 2) Probe diameter has influence on the detection sensitivity, with the coil diameter increasing, the detection sensitivity decreases significantly. To increase detection sensitivity, the probe coil diameter must be equal to or less than the length of defects. 3) Probe placed has a great influence on the detection sensitivity, with lift-off distance increasing, detection sensitivity decreases rapidly. 4) Excitation coil has more influence than detection coils on detection sensitivity, increased excitation coils turns can help to improve the detection sensitivity, but increased detection coils turns will decrease the detection sensitivity. Acknowledgment. This work is supported by the carrying tools and equipment of Ministry of education key laboratory (09JD03).
References 1. Yang, B., Luo, F., PenN, M.: Identification of Corrosion Fringe in Pulsed Eddy Current Nondestructive testing. Chinese Journal of Mechanical Engineering 44(12), 75–79 (2008) 2. He, Y., Luo, F., et al.: Pulsed Eddy Current Technique for Defect Detection in Aircraft Riveted Structures. NDT & E International 43(2), 176–18 (2010) 3. Ren, J., Lin, J., Gao, C.: Electromagnetic Detection. Mechanical Industry Press (2000) 4. Kim, J.-W., Shin, J.-H.: A Study of a Dual-electromagnetic Sensor System for Weld Seam Tracking of I-butt Joints. Proc. Instn Mech. Engrs Part B: J. Engineering Manufacture 217, 1305–1313 (2003) 5. Li, G., Ma, H., Shen, J., He, F.: Analysis of Detection Principle and Influential Factors of Eddy Current. Chinese Journal of Sensors and Actuators 22(11), 1165–1169 (2009) 6. Zhang, Y., Sun, H., Luo, F., Yang, B.: Design of a Novel Pulsed Eddy Current Testing Probe Based on 3D Magnetic Field Measurement. Chinese Journal of Mechanical Engineering 45(8), 249–252 (2009) 7. Gao, X., Zhu, Z., Zhang, W.: Study on Structure Optimization of Eddy Current Probe. Chinese Journal of NDT 28(6), 28–30 (2004)
Feasibility of Coordinate Measuring System Based on Wire Driven Robot Ji-Hui Zhou, Qing-Song Cao, Fa-Xiong Sun, and Lan Bi College of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang 330013, China
Abstract. The coordinate measuring machine systems (CMMS) are widely used for part inspections in manufacturing plants, which mostly include bridge CMMS and horizontal CMMS driven by motor and portable CMMS operated manually. Wire-driven parallel kinematic manipulators (PKMs) have advantages of flexibility, accuracy and large workspace. This paper investigates the feasibility of the coordinate measuring system based on wire-driven PKM. The forward and inverse position solutions are obtained by MATLAB simulation through the kinematic analysis of the manipulator. The controllable workspace with tension conditions and stiffness conditions are obtained by means of the static analysis. Analysis results show that the manipulator have high precision, high speed and large workspace, these advantages just meet the measure requirements of coordinate measuring systems. Finally, a primary experiment is presented to show that the measuring platform of this manipulator can move smoothly and its measurement error is relatively low. The feasibility of taking the wire-driven PKM as coordinate measuring system has been validated by theoretical and experimental study. This research maybe lays a foundation for the further application of wire-driven PKM in the field of coordinate measuring. Keywords: Wire-driven parallel kinematic manipulators (PKMs), Coordinate measuring system, Feasibility.
1 Introduction As one of the most indispensable metrological instruments for inspections and quality control in manufacturing plants, coordinate measuring machine systems (CMMS) are widely used in many fields such as mechanical manufacturing, automotive industry, electronic industry, aerospace industry and national defense industry. The first CMM was developed by the Ferranti Company of Scotland in the 1950s, although this machine only had 2 axes. The first 3-axis models began appearing in the 1960s and computer control debuted in the early 1970s. After the 1970s, CMMS have made rapid development [1]. With the development of modern industry, fast and accurate measurement is an important research subject [2]. At the same time, novel type mechanisms need to be designed. Wire-driven parallel kinematic manipulators (PKMs) possess a number of promising advantages over the conventional rigid-link manipulators, such as simple and lightweight mechanical structure, high-loading capacity, large workspace, low moment D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 450–459, 2011. © IFIP International Federation for Information Processing 2011
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inertia and high speed motion. The early study on wire-driven PKMs is the application in cargo handling. Over the years, a number of different wire-driven PKMs designed for a wide variety of applications in large-scale manufacturing such as welding, cutting, grinding, assembly, fixturing, paint stripping, and machining. An example of wire driven robots that are currently in use is the NIST Robot Crane[3]. The NIST Robot Crane is a large-workspace robot for painting and maintaining aircraft which is also suitable for material handling in warehouses and storage facilities [4]. Recently, six degrees of freedom wire-driven PKMs in the application of a large radio telescope is presented [5]. The potential for cable robots are given to be used in a variety of applications, the studies on the wire-driven PKMs will be promoted. The novel three degrees of freedom (DOF) coordinate measuring machine driven by four wires is proposed in this paper. Based on the kinematic analysis of the manipulator, it is confirmed that this manipulator have large workspace, high moment precision and low moment error after the simulation of MATLAB. A primary experiment is presented to show that the moving platform of this manipulator can move smoothly, its measurement error is relatively low and measurement precision is relatively high. The feasibility of wire-driven PKM used as coordinate measuring system is verified by theoretical analysis and experiment. This study will play an important role in pushing forward the application of wire-driven PKM in coordinate measuring field.
2 Overal Design The basic function of CMMS is to gain the actual shape of a work piece. The actual shape of the work piece is obtained by probing the surface of the work piece at discrete measuring points which can then be analyzed via regression algorithms for the work piece of features. Every measuring point is expressed in terms of its measured coordinates. Based on this principle of measurement, the overall plan design of the measuring system is presented in figure 1.
Fig. 1. Block diagram of the system
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The measuring system includes four main components: the main structure, measuring system, touch trigger probe and electrical control system. The main structure is an 1160mm×550mm×1000mm PKMs driven by four wires. The accurate control of the measuring platform is obtained through using step motor to control the lengths of the wires. The step motor controlled by pulse-to-step is generated by a 51 microcontroller. As one of the most important part, the touch trigger probe greatly influences measurement accuracy and precision. The touch trigger probe named TP60 is used in this paper which has a spring loaded ruby ball stylus. The different functions can be realized by the electrical control system through the way of microcontroller programming. The control signal can be import from keyboard or from 51 microcontroller and PC serial communications. After receiving the signal, the microcontroller jump to the corresponding procedure to realize the different functions, such as display coordinates on the LED nixie tube, the measuring platform is programmed to moving up and right. As the probe touched the surface of the component, the stylus deflected and simultaneously the microcontroller sent information of coordinate (X.Y.Z) to the PC computer. Measuring element of the target such as the shape of the component, the shape of the component and position was obtained by fitting the information of coordinate (X.Y.Z).
3 Theories Analysis 3.1 Structure Analysis The schematic diagram of completely restrained wire-driven PKM is shown in figure 2.
Fig. 2. PKM driven of four wires
The measuring platform is connected to static platform through four driving cables, AA’, BB’, CC’, DD’. The length of each cable is denoted as Li (i = 1, 2, 3, 4). The cable is connected to the static platform at point A, B, C, and D. The cable is connected to the measuring platform at point A’, B’, C’ and D’. The center of ABCD and A’B’C’D’ expressed in O and P. Make coordinate system O-xyz become the static coordinate system. Let coordinate system O-xyz becomes the moving coordinate
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system. The unit vector in the direction of the cable is ei . The manipulator has only 3 Cartesian degrees-of-freedom(x, y, and z). In Figure 2, the design parameters for the PKM driven by 4 wires are 2a (static platform length), 2b (static platform width), 2c (measuring platform length), and 2d (measuring platform width). ti is the cable tension applied for the cable. ri is the position vector from the origin of P to the cable connection. For static equilibrium the sum of external forces and moments exerted on the measuring platform by the cables must equal to the resultant external wrench exerted on the environment.
F=AT
(1)
Where T= (t1 L t4 ) is the vector of scalar cable forces, F is the resultant external
wrench vector exerted on the environment by the measuring platform, A = [e1 L e4 ] is the statics jacobian matrix. L= ( L1 × e1 L L4 × e4 )T is the vector of cable length. Vi is the cable translational velocity applied for the cable, expressed in V. AT is the transpose matrix of A matrix. By means of the method of the vector analysis, the following matrix form can be obtained L= AT V
(2)
The analytical expression of cable forces is obtained via the first equation. In other words, to invert (1) we adapt the well-known particular and homogeneous solution T= A+ F + ( E − A+ A) q
(3)
Where A+ is the Moore–Penrose pseudo inverse of A, A+ F is the minimum norm solution of (1), q is an arbitrary 4-vector, E is the 4×4 identity matrix. 3.2 Position Analysis 3.2.1 Inverse Position Analysis In static coordinate system, A’B’C’D’ is expressed in K 5 K 6 K 7 K 8 , while in moving
coordinate system, it is expressed in K 5' K 6' K 7' K8' . The coordinates (Xp, Yp, Zp) is the position of P relating the static coordinate system. According to the closed vector approach, the following equation can be described K i = K i' + P
Therefore, the length of each cable can be calculated as follows
⎡c − a ⎤ ⎡ X p ⎤ ⎡c − a ⎤ ⎡ X p ⎤ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ L1 = K1 − K 5 = ⎢b − d ⎥ − ⎢ Yp ⎥ , L2 = K 2 − K 6 = ⎢ d − b ⎥⎥ − ⎢ Yp ⎥ ⎢⎣ 0 ⎥⎦ ⎢⎣ Z p ⎥⎦ ⎢⎣ 0 ⎥⎦ ⎢⎣ Z p ⎥⎦ ⎡a − c ⎤ ⎡ X p ⎤ ⎡a − c⎤ ⎡X p ⎤ ⎢ ⎥ ⎢ ⎥ ⎢ ⎥ L3 = K 3 − K 7 = ⎢ d − b ⎥ − ⎢ Yp ⎥ , L1 = K 4 − K8 = ⎢⎢b − d ⎥⎥ − ⎢ Yp ⎥ ⎢⎣ 0 ⎥⎦ ⎢⎣ Z p ⎥⎦ ⎢⎣ 0 ⎥⎦ ⎢⎣ Z p ⎥⎦
(4)
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The inverse position solutions can be expressed as
⎧L ⎪ 1 ⎪L ⎪ 2 ⎨ ⎪ L3 ⎪ ⎪ L4 ⎩
= L1 = (c − a − X p ) 2 + (b − d − Yp ) 2 + Z p 2 = L2 = (c − a − X p ) 2 + ( d − b − Yp ) 2 + Z p 2
(5)
= L3 = ( a − c − X p ) 2 + ( d − b − Yp ) 2 + Z p 2 = L4 = ( a − c − X p ) 2 + (b − d − Yp ) 2 + Z p 2
3.2.2 Forward Position Analysis The relationship between the length of each cable and ( X p ' Yp ' Z p ) can be obtained via
invert equation Li = Li , so the forward position solutions can be expressed as
⎧ L12 − L24 ⎪X p = 4 × ( a − c) ⎪ 2 2 ⎪ ⎪Y = L2 − L1 p ⎨ 4 × (b − d ) ⎪ ⎪ Z p = − L24 − ( a − c − X p ) 2 − (b − d − Yp ) 2 ⎪ ⎪⎩ L12 − L24 = L22 − L23
(6)
Whatever the position and pose of the mobile platform is, the length of each cable must meet the Eq. (6). The position and pose of the measuring platform corresponding to certain cable lengths thus are determined via the forward position analysis of parallel wire-driven robot. 3.3 Workspace Analysis 3.3.1 Controllable Workspace The controllable workspace is defined as a set of position and orientation for the platform, which meet equilibrium of force and torque, and the tension of each cable is required to be positive [6]. The controllable workspace of the manipulators can be determined by checking the tension of each cable on the basis of the principle of vector closure. Therefore, the manipulators to meet the principle of vector closure should be proved firstly. According to the principle of vector closure, in a 3-dimensional real space, the arbitrary vector v is closed only if vector v has at least 4 vectors (w1, w2, w3 and w4) satisfying the following two conditions. Condition 1 is that in the four vector (w1 ... w4),
any three vectors are linearly independent; Condition 2 is that ∑ i =1α i wi = 0 (for any 4
value of i should meet α i > 0 ). Let unit vector ei expressed in wi . Take the cable tension ti expressed in α i . Assume the resultant external wrench exerted on the environment is zero ( the gravity of each rope is ignored), the following matrix can be expressed: AT=0. Therefore,
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∑
4 i =1
α i wi = 0 can be obtained through the equation of
∑
4
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t e = 0 . Because the me-
i =1 i i
chanisms does not produce singular, in the four vector (w1 ... w4), any three vectors are linearly independent. The manipulators to meet the principle of vector closure can be proved through the above analysis. According to the equation of T= A+ F + ( E − A+ A) q, if the tension solution in the above equation can always be made positive for all positive homogeneous solutions regardless of the external disturbance F, the boundary of the workspace can therefore be generated by letting F=0. Therefore, the tension of each cable can be positive if each element of ( E − A+ A) q is positive. So the controllable workspace bound can be expressed as follow. ( E − A+ A) > 0
(7)
3.3.2 Workspace with Tension Conditions The workspace with tension conditions is defined as a set of position and orientation under the conditions of the controllable workspace in which the tensions ti in the cables must range between a pre-tension tmin and a maximum tension tmax and the gravity or elasticity of each rope is ignored. Therefore, the workspace with tension conditions can be determined by the tensions in each cable and the external forces and torques exerted on the environment. Assume the external forces and torques exerted on the environment is zero, in other words F=0. With k=tmax/tmin is defined as critical tension factor, the workspace with tension conditions can be calculated as follows
⎧ max i =1L4 Bi ≤K ⎪ min i =1L4 Bi ⎨ ⎪ B = ( E − A+ A) > 0 ⎩
(8)
Where B = ( E − A+ A) > 0 is the 4×4 matrix. 3.3.3 Workspace with Stiffiness Conditions The workspace with tension conditions for n DOF PKMs is defined as a set of position and orientation under the conditions of the controllable workspace in which the pose greater than n positive eigenvalues of stiffness matrix is not less than stiffness coefficients K’ [6]. Therefore, the stiffness matrix should be calculated firstly. The stiffness matrix of driven by m (m ≥ n+1) wires is obtained by Verhoeven [7].
K = K 0 AΛAT (9) Where K = ki × L is the per unit cable length stiffness, ki is the cable stiffness ap0
0 i
plied to the cable, L0i is the original cable length applied to the cable, matrix A must meet the condition of F = AT , with AT is the transposed matrix of matrix A, −1
Λ = diag ( Li (1 + K 0 ti )) is a diagonal matrix. The position and pose of the mobile
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platform can corresponding to certain cable lengths and tension, Li and ti are the certain cable lengths and tension. −1
Generally, K 0 ti ∞ is small enough which can be ignored [8]. The manipulators rigidity performance is determined by geometrical arrangement of wires and the position and orientation of measuring platform. According to formula (9) we can conclude that K is a symmetric positive semidefinite matrix which have n positive eigenvalues λKi ( i = 1 2L n ) definitely. Therefore, the workspace with tension conditions must satisfy the following constraints ⎧⎪ max i =1L4 λKi ≥ K ′ ⎨ + ⎪⎩( E − A A) > 0
(10)
3.4 Analysis of Kinematic Error 3.4.1 Analysis of Error Motion The kinematic error for measuring platform moving from one place to another can be obtained via plus the error in each coordinate direction respectively. This article scatters a specific space into different points, and uses the kinematics precision analysis in calculating the variation of the position and pose of measuring platform corresponding to allowable pulse-to-step in different point. Stepper motor can transform the digital input pulse revolving or the straight line increase activity electromagnetism functional element. When stepping drive to receive a pulse, it drives stepper motor rotate in the direction set by a fixed point of view, then the cable length can be changed in a definite value ΔL . The perimeter of the roller for step motor is 60 mm. So ΔL can be calculated as
ΔL =
1.8 0.3 × 60 = mm 360 × SN SN
(11)
Among them, SN is the subdivision number of stepper motor. So the minimum change of each cable length is ΔL. The measuring platform with moving left and right is X, moving forward and backward rd is Y and moving up and down is Z. When measuring platform moving up and down, 51 microcontrollers give synchronous control of all cable’s speed, the cable length can change ΔL every time. The kinematic error will not produced only in the condition of x=0 and y=0. When measuring platform moving left and right, 51 microcontrollers give synchronous control of the first cable and the second cable’s speed and synchronous control of the third cable and the fourth cable’s speed. Note ΔL1 = m ∗ ΔL is the change of the first and the second cable length, note ΔL2 = n ∗ ΔL is the change of the third and the fourth cable length. The kinematic error will produced in the condition of y≠0. In this paper, m and n are limited to the same ranges, m, n∈ [0, 20], and let them be the positive integer. The value of m and n can be obtained in the condition of the kinematic error in the Z ordinate direction is the
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minimum count. When measuring platform moving forward and backward, 51 microcontrollers give synchronous control of the first cable and the fourth cable’s speed and synchronous control of the second cable and the third cable’s speed. Note ΔL1 = m ∗ ΔL is the change of the first and the fourth cable length, note ΔL2 = n ∗ ΔL is the change of the second and the third cable length. The method of gain the value of m and n is similar with the analysis of moving left and right. With different position and pose of the measuring platform, the kinematic error and accuracy will change. So the relationship between the kinematic error, accuracy and some parameters should be analyzed by MATLAB simulation. Using computer simulation, we can conclude that 1) Littler the size of measuring platform, lower the error for all movement and the accuracy for moving up and down, higher the accuracy for moving right, left, forward and backward. Therefore, the size of measuring platform can be made as small as possible but it has a lower limit. 2) The position and pose in the direction of z is the critical element for the accuracy of moving up and down, and littler the count of z, higher the accuracy. 3) If the error of moving right, left, forward and backward remained to lower, the original position x, y should be positive and remain low around zero, the position z and moving distance h should be remain low. 3.4.2 The Best Workspace A best workspace B which covering x, y ∈ (-100,100) and z ∈ (-924, -724) is obtained by computer simulation. In this workspace, the kinematic accuracy in the direction of coordinate x range from 0.0167 mm to 0.4165 mm; the kinematic accuracy in the direction of coordinate y range from 0.0513 mm to 0.7244 mm; the kinematic accuracy in the direction of coordinate z range from 0.0105 mm to 0.0116 mm. Therefore, the kinematic accuracy of measuring platform is relatively high. If the moving distance is 100 mm, the kinematic error in the direction of coordinate x range from 0mm to 1.82955 mm; the kinematic error in the direction of coordinate y range from 0 mm to 1.85239 mm; the kinematic error in the direction of coordinate z range from 0.428648 mm to 7.17298 mm. Therefore, the kinematic error of measuring platform is relatively low. The above analyzed results show that the manipulators have high kinematics precision and low kinematics error in the workspace B, these advantages just meet the measure requirements of coordinate measuring systems.
4 Experiment This part attempts to verify the rationality and feasibility of adopting wire-driven PKM as coordinate measuring system through experiments. As some limitations, the designed probe is replaced by some parts in the following experiment. Therefore, checking the probe contacts with the work piece is determined by visual inspection. Besides, the kinematics error of the measuring platform is discussed, it includes the errors of the probe, the distortion of each rope, external conditions and so on. The material object photography of CMM is shown in figure 3.
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Fig. 3. The material object photography of the designed CMMS
In the experiment, the size of the two rectangular objects is measured in the best working space. The experimental data are in the following table, the error can be obtained via the comparison of measure and actual size. Table 1. The record of the experimental data (mm) Initial Coordinate Values Terminal Coordinate Values
735.85
788.33
10.81
80.86
2.48
44.98
788.33
735.97
80.86
9.95
44.98
3.34
Measure Size
52.48
52.36
70.05
70.91
42.50
41.64
Actual Size
49
49
64
64
49
49
Error
3.48
3.36
6.05
6.91
6.5
7.36
740.64
803.94
3.18
69.22
4.71
42.03
803.94
739.21
69.22
2.77
42.03
3.80
Measure Size
63.3
64.73
66.04
66.45
37.32
38.23
Actual Size
60
60
60
60
43
43
Error
3.3
4.73
6.04
6.45
5.68
4.77
Initial Coordinate Values Terminal Coordinate Values
Experimental data show that the measurement error of the designed CMMS is up to a few millimeters, which is somewhat of big. The main factors for the measurement error are human factors, such as the visual error in checking the probe contacts with the work piece and reaction time of human. If the designed probe is used in the experiment, the measurement error should be greatly reduced and it would meet the measure requirements of coordinate measuring systems. Through the observation of
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the experiment we can conclude that the measurement platform can moved smoothly even in the condition of fast moving. The feasibility of adopting wire-driven PKM as coordinate measuring system is verified once again.
5 Conclusion The forward and inverse position solutions are firstly obtained by means of the static analysis and the controllable workspace, workspace with tension and stiffness conditions are presented in this paper. Then the kinematics precision and error analysis of the wire-driven PKM is given by MATLAB simulation based on the kinematic analysis of the manipulator. The best workspace in which the manipulators have high kinematics precision and low kinematics error is obtained. These advantages meet the measure requirements of coordinate measuring systems exactly. Therefore, the theories analysis verifies the feasibility of adopting wire-driven PKM as coordinate measuring system. Furthermore, the overall scheme of CMMS based on wire-driven PKM is put forward in details. Finally, a primary experiment is presented to show that the measuring platform of this manipulator can move smoothly and its measurement error is relatively low. The feasibility of adopting wire-driven PKM as coordinate measuring system is verified both by theoretical and experimental study.
References 1. Liu, Z., Ni, X.: Present state and developing trend of three-coordinate measuring machines. Machinery 42(480), 32–34 (2004) 2. Zhang, G.: The development tendency of coordinate measuring machines. China Mechanical Engineering 11, 222–226 (2000) 3. Edward, A., Roger, B., Nicholas, D.: Summary of Modeling and Simulation for NIST RoboCrane Applications. In: Deneb Internation Simulation Conference and Technology Showcase, Detroit, MI (1997) 4. Goodwin, K.: RoboCrane Construction of Bridges. In: Transformation Research Record, Transformation Research Board, pp. 42–46 (1997) 5. Zheng, Y.Q., Liu, X.W.: Research survey and development tendency of wire-driven parallel manipulators. China Mechanical Engineering 14(9), 808–810 (2003) 6. Verhoeven, R., Hiller, M., Tadoroko, S.: Works-pace, stiffness, singularities and classification of tendon-driven Stewart platforms. In: Proceedings of the 6th International Symposium on Advances in Robot Kinematics, pp. 105–114 (1998) 7. Ming, A., Higuchi, T.: Study on Multiple Degree of Freedom Positioning Mechanisms Using Wires (Part I): Concept, Design and Control. International of the Japan Society for Precision Engineering 29(6), 131–138 (1994) 8. Liu, X.W., Zheng, Y.Q.: Kinematic analysis of a 6-dofwire-driven parallel kinematic manipulator. Chinese Journal of Mechanical Engineering 38(supplement), 16–20 (2002)
HSFDONES: A Self-Leaning Ontology-Based Fault Diagnosis Expert System Framework XiangBin Xu School of Mechatronics Engineering, East China Jiaotong University, 330013 Nanchang, P.R. China [email protected] Abstract. HSFDONES is an expert system fault diagnosis which makes the fault diagnosis working more intelligently, HSFDONES uses the ontologybased self-leaning theory and technology to build fault diagnosis expert system. The fault diagnosis knowledge structure is defined and the relevant structure ontology and core fault ontology is researched in HSFDONES; the fault diagnosis data warehouse is built, the decision tree and Apriori algorithm are used to acquire fault knowledge to realize HSFDONES’s ontology self-learning. HSFDONES offers system framework for building intelligent fault diagnosis system. Finally the agricultural machinery’s hydraulic fault diagnosis expert system was developed on the basis of the framework. Keywords: HSFDONES, Ontology, Fault Diagnosis, Self-learning, Data Mining.
1 Introduction HSFDONES (Hydraulic System Fault Diagnosis Ontology Expert System, hereinafter referred to as HSFDONES) is an ontology-based hydraulic system fault diagnosis expert system. The system architecture of HSFDONES is shown in Fig.1.
Fig. 1. The System Architecture of the HSFDONES D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 460–466, 2011. © IFIP International Federation for Information Processing 2011
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HSFDONES takes data warehouse technology to organize and manage heterogeneous system fault information, the ontology is used as HSFDONES’ knowledge backbone. In order to realize ontology self-leaning, HSFDONES takes learning algorithm in the field of machine learning to realize diagnosis ontology self intelligent learning, and finally HSFDONES uses Jena and Topic Maps as its reference and presentation engine respectively.
2 HSFDONES Data Warehouse 2.1 Data Warehouse Structure Hydraulic system fault information is stored in the media such as database, Excel, TXT and other file formats, the different format data can not offer knowledge efficiently. Data warehouse technology is an effective solution to solve this problem [1]; data warehouse technology can extract, handle and standardize large, varied data. The data in warehouse is organized in the form of the data cube, after data ‘s standardization and consistency, the data can be loaded and imported into the data warehouse’s cubes, the hydraulic system fault data warehouse’s structure is shown in Fig.2.
Fig. 2. HSFDONES Data Warehouse Structure
2.2 Data Warehouse Construction HSFDONES take Mondrian as its OLAP[2] engine to build the hydraulic system fault diagnosis data warehouse,Mondrian is java-based, open source data warehouse engine, the hydraulic system fault diagnosis data warehouse and data cube of each module built by Mondrian are presented in the form of XML and data tables. HSFDONES use the JDBC technology to realize data extraction, cleaning and transformation, after that the data can be loaded into Mondrian’s data warehouse. Once HSFDONES’ fault data warehouse is constructed, the knowledge-learning algorithm can extract knowledge from it efficiently.
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3 HSFDONES Knowledge Structure 3.1 Oontology-Based Knowledge HSFDONES core ontology includes two parts: the hydraulic structure ontology and the hydraulic fault ontology. Hydraulic structure ontology describes the structure of hydraulic system and assembly relations; Hydraulic fault diagnosis ontology describes the hydraulic system’s critical fault information, which means hydraulic system failure and their relationship. In order to design and build the HSFDONES core ontology, first we should define the domain area[3] of hydraulic system’s fault diagnosis, which can be done by consulting domain experts, filed researching and statistics of historical data. After that, we can make abstraction to identify and define the ontology classes, class hierarchy, class property, restrictions, characteristics (such as symmetric, transitive, etc), finally build individual instances of ontology classes to get HSFDONES diagnosis ontology model. 3.2 HSFDONES Fault Knowledge Definition The hydraulic system’s fault is described in three parts, which are fault phenomenon, fault causes and failure sources (the parts or component which causes the failure). Fault phenomenon is the presenting symptoms, fault source is parts or components where the fault raises, fault causes is information chain which can track from fault phenomena to fault source. HSFDONES fault knowledge can be described in fault triples: HSFDONES fault knowledge should figure out the connection which links the fault phenomenon to the fault source through some logical analysis. 3.3 HSFDONES Fault Ontology Construction HSFDONES hydraulic system fault ontology is built in the seven-step ontology way. After consulting domain experts, we get the following fault diagnosis knowledge: 1) IF “the fuel tank can not change direction” AND “the valve can not return to the center position” THEN “the electromagnetic iron is damaged”; 2) IF “the valve can not return to the center position” AND “the electromagnetic iron is good” THEN “the gap is too small” OR “the oil is polluted”; 3) IF the electromagnetic iron is good” THEN “the coil is aging” OR “the switch is circuited”. Let’s take the first diagnosis knowledge as an example to show the process of ontology constructing: The fault knowledge triples are: < Fuel tank can not change direction, Valve can not return to the center position, Electromagnetic iron is damaged>
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According to the fault knowledge, we can define related ontology knowledge in the ontology knowledge base, namely: Fuel tank’s changing direction: Can not change -> fault phenomenon Valve resetting position: Can not reset -> fault cause Electromagnetic iron Status: Is damaged -> fault source The fault phenomena, fault causes and fault source described in HSFDONES fault knowledge triple can modeled as ontology’s class, their status (such as: "can not change direction ", "can not reset position", etc.) are modeled as class properties associated the corresponding ontology class. Different from the hydraulic system structure ontology, we just build the fault diagnosis core ontology, and the fault diagnosis core ontology can self-learn new ontology once the hydraulic system new failure occurs, which means fault diagnosis core ontology can grow dynamically. The fault diagnosis should be formalized so as to be understood by machine, we build the fault diagnosis ontology model in Protégé IDE[4], after that we should transfer and formalize the fault diagnosis ontology model, HSFDONES use OWL as the ontology coding language to formalize and describe fault diagnosis ontology model[5], OWL-based ontology can be shared between systems.
4 HSFDONES’ Self-learning Algorithms 4.1 Self-learning Algorithms HSFDONES ontology self-learning algorithm can excavate fault knowledge from the hydraulic fault data warehouse, which can be transferred into ontology by referring to the hydraulic system structural ontology and core fault ontology, and the new-learned fault ontology are stored in the fault ontology library. Decision tree[6] algorithm is efficient classification algorithm in data mining, it can extract decision-making knowledge from the training data, decision tree’s knowledge is described in the tree-style, which includes internal nodes, fork and leaf nodes, the internal nodes in decision tree represent a test property, the fork in decision tree represent classification, the leaf in decision tree nodes represent a diagnosis result, the decision tree can display knowledge in a graphical way, the decision tree uses ID3 and the C4.5 as learning algorithm, ID3 is mainly applied to discrete attributes, C4.5 classification can leaning from both discrete and continuous attributes, C4.5 builds decision tree based on information entropy theory, which calculate the information gain for each attribute recursively, select the highest information gain attributes as the split attribute, the information gain is calculated as following: 1) Compute the entropy of dataset: k
Info( S ) = −∑ (( freq (Ci , S ) / S ) * log 2 ( freq(Ci , S ) / S )) i =1
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2) Compute the Weighted entropy sum of property:
Info x (T ) = −∑ (( Ti / T ) * Info(Ti )) 3) Compute the Info Gain of property:
Gain ( X ) = Info (T ) − Info x (T ) The freq (Ci, S) represents the sample size belongs to class Ci in training set S, Gain (X) represents information gain of the property X. C4.5 learning algorithm finds max information gain property as the root of decision tree, and then call the algorithm recursively in the split data set, until a whole decision tree is constructed; once the decision tree is built, we should prune it to get a refined, non-redundant decision tree. 4.2 Knowledge Extraction The knowledge leaned by decision tree is showed in a “IF ... ... Then ... ..." style, we can extract the knowledge rule from decision trees as follows: 1) The fault knowledge rule is paths which link the root to each leaf respectively; 2) The internal test nodes along the path represent the premise of the rule (IF) section and each leaf node at the end of the path represent conclusions (THEN).
5 HSFDONES Knowledge Inference and Presentation 5.1 Knowledge Inference HSFDONES take Jena as it’s of inference engine, Jena is Java-based open source semantic web toolkit developed by HP, it offers a programming environment for parsing RDF, RDFS and OWL ontology, and Jena provides a rule-based inference engine. Jena’s inference engine can be used in OWL-based ontology, its inference is based on direct graph, if can offer forward reasoning, backward reasoning and reasoning mixed. The rule sets Jena get are bound to the data model, which can form a new reasoning input, so the query results returned by the Jena inference engine include both original data triples and the new knowledge rules inferred from the ontology library. In HSFDONES system,once the hydraulic fault diagnosis ontology OWL ontology model is imported into Jena’s ModelFactory, the Jena inference engine can transform the OWL ontology into a an ontology inference graph, then the Jena inference engine can take the ModelFactory API to interact with the hydraulic fault diagnosis ontology, which means the end-user can query and get hydraulic fault diagnosis knowledge. In the HSFDONES system, the Jena API is embedded into the JSP code, the diagnosis knowledge inferred by the Jena is transformed in a XTM-formatted style, which finally is showed in the end-user’s web browser. 5.2 Knowledge Presentation HSFDONES take the Topic Maps to present the fault diagnosis knowledge, Topic Maps can organize and describe the ontology knowledge topics based on meta-data,
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and the ontology knowledge organized and described on the topic-based can be navigated and explored easily. The HSFDONES knowledge topic map includes three basic elements: topic, association and the occurrence. In the topic map, HSFDONES fault source organized can be located easily,and the fault correlation can be displayed directly, which means a easy way for the user to navigate, explore and trace the hydraulic fault, this is mostly helpful for the fault detection and prevention. HSFDONES take the TM4J as it’s topic map engine, TM4J offer a user-friendly interface and a powerful a secondary development environment, which make it flexible and extensible, TM4J take a XML-based specification language-XTM to describe the ontology knowledge and its relation, so HSFDONES needs a data adapter, which bridge the gap between the OWL and XTM, the working processes of the adapter is showed in Fig.3.
Fig. 3. HSFDONES Knowledge Representation
6 Conclusions Taking the fault diagnosis expert system as an example, this paper details in the theory and implementation of fault information organization, ontology knowledge definition, ontology self-leaning algorithm, ontology inference and representation. The open source solution is used here and the HSFDONES was successfully developed based the researching result. The successful research and application of HSFDONES offer useful guidance for the development of intelligent diagnosis expert system.
Acknowledgements This study was supported by JiangXi Natural Science Foundation(No.2009GZS0015), JiangXi Educational Committee Foundation(No.GJJ10467), National High-tech Research and Development Program of China(863 program) (No. 2009AA04Z106) and Jiangxi Key Laboratory of Ministry of Education for Conveyance and Equipment.
References 1. Yuan, H.: OLAP and Data Warehouse Modeling Techniques. Computer Application Research 12, 61 (1999) 2. Liu, Y., Chang, G.: OLAP-Based Relational Database Research. Computer Engineering and Applications 38, 127 (2001)
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3. Liu, J., Hu, L.: Skeleton of Boiler-Based Fault Detection System of the Domain Ontology Construction. Henan University of Science and Technology: Natural Science Edition 3, 36 (2008) 4. The Protégé project, http://protege.Stanford.Edu, 2009-04 5. Du, N., Huang, D.: Ontology-Based Fault Diagnosis for Chemical Process. Computer Integrated Manufacturing System 4, 587 (2004) 6. Wei, H., Kamber, M.: Data Mining Concepts and Techniques. Mechanical Industry Publishing, China (2002) 7. Lan, Y.: Excavator Hydraulic System Fault Diagnosis and Rule Out. Water Resources and Technology 2, 71 (2006)
Nondestructive Measurement of Sugar Content in Navel Orange Based on Vis-NIR Spectroscopy Chunsheng Luo1, Long Xue2, Muhua Liu1,*, Jing Li1, and Xiao Wang1 1
Engineering College, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, P. R. China 2 School of Mechanical and Electronical Engineering, East China JiaoTong University, Nanchang, Jiangxi 330013, P.R. China
Abstract. The Vis-NIR spectroscopy technology was studied on nondestructive measurement of sugar content in navel orange. Three different spectral ranges of 450-1000nm,1000-1800nm and 450-1800nm were selected, respectively and five different spectral pre-processing methods of Standard Normal Variate (SNV), first derivative (FD), second derivative (SD), multiplicative scatter correction (MSC) and smoothing were used for establishing the partial least squares(PLS)models, which was determined the sugar content in navel orange. The results showed that the model developed from 450-1800nm spectroscopy after SNV pre-processing achieved the optimal performance. The correlation coefficient (r2) of the calibration set and validation set were 0.9349 and 0.8514 respectively, and the root mean squared error of calibration and validation sets were 0.8017 and 1.1649, respectively. The research indicated that the Vis-NIR spectroscopy technique was feasible to nondestructive measurement of sugar content in navel orange. Keywords: Vis-NIR spectroscopy, nondestructive measurement, sugar content, navel orange.
1 Introduction Currently, the fresh fruit need to meet certain quality grade requirements before they are shipped to the marketplace. These requirements include fruit outward characteristics (i.e. size, color, and shape) and internal quality attributes (sugar, acid, firmness, etc.). With the continuous improvement of people's living standard, the quality requirements of fruit are more and more focus on internal quality attributes. As a quality attribute of fruits, sugar content will directly impacts on consumers’ purchase demand. Visible-Near infrared spectroscopy (Vis-NIRs) is one of the fastest growing analytical technologies in recent years. It has several advantages compared to traditional chemical methods: speed, non-destructed of sample, avoidance of the use of chemicals and simplicity of sample preparation. Researchers have shown for years that Vis-NIR spectroscopy is a suitable technique for sugar content measurement in various *
Corresponding Author. E-mail: [email protected]
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fruits: nectarine[1], apple[2-5], Nanfeng mandarin[6], and citrus[7]. Vis-NIR was also used for measurement the quality attributes of tea[8], Chlorophyll[9], pork[10], etc. The development of equipment with improved electronic and optical components and the advent of computers capable of effectively processing the information contained in Vis-NIR spectra has facilitated the expansion of this technique in an increasing number of fields. This paper focuses on the navel orange sugar content results obtained by using different spectral ranges and different spectral pre-processing methods to establish the validation models of partial least squares (PLS).
2 Materials and Methods 2.1 Navel Orange Samples Two hundred and seventy navel orange samples were used for the experiment. These navel oranges were harvested from an orchard at Ningdu county, Jiangxi province, China. The samples were placed at room temperature (10 ) and relative humidity (60%) for 168h before the experiment. Total of samples were divided into two groups: 185 samples were designed as calibration models set for model development and the remaining as validation set for validation. The selection of samples for calibration and validation was random and the samples’ sugar content of validation was among the region of calibration samples’ sugar content.
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2.2 Vis-NIR Imaging System Figure1 shows the Vis-NIRs imaging system. The system mainly consisted of an imaging spectrograph QualitySpec Pro (Analytical Spectral Devices, Inc., USA) with a
Fig. 1. Vis-NIRs system
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spectral range from 350nm to 1800nm, appropriate lighting sources, optical fiber and a computer. Spectra of the samples were obtained with 1nm interval and scan frequency was 10 times. Indico software (version 4.0, Analytical Spectral Devices, Inc., USA) was used for spectra data. Each navel orange was measured 6 times, rotating 60° was taken on the equatorial zone of the navel orange. The average of the 6 measurements was used later for date processing. In the measurement, note that to prevent light leakage and avoid scratches, scars and other surface defects as much as possible. 2.3 Experimental Procedure After the imaging, Extracted juice of each navel orange flesh was filtered and then taken for sugar content measurement by a digital refractometer (Model PR-101,Atago Co. Ltd, Tokyo, Japan). Each sample was measured 9 times with the squeezing juice. The average of the 9 measurements was used later for date processing. 2.4 Spectral Data Processing The raw Vis-NIR spectral profiles of navel oranges are shown in figure 2. It can be seen that the spectra contain a lot of noises from wavelengths between 350 to 449nm, and absorption peak due to water around 1000nm. Thus, the raw spectrum was divided into three different spectral ranges: 450-1000nm, 1000-1800nm and 450-1800nm, and then five different spectral pre-processing methods of standard orthogonal variable transformation (SNV), first derivative (FD), second derivative (SD), multiplicative scatter correction (MSC) and smoothing were used. Spectral pre-processing of raw spectra data were applied to all measured spectra to reduce the effects of high-frequency random noise, baseline drift, sample particle size and light scattering etc, which can effectively adjust near-infrared spectrum[11].
Fig. 2. Raw spectra of navel oranges
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Software Unscrambler (version 9.7, CAMO AS, Trondheim, Norway) and Matlab 7.1(Mathworks, Inc., USA) were used to analysis Vis-NIR spectroscopic data. Spectra from the Indico software were exported to suitable format.
3 Result and Discussion 3.1 Pre-processing Methods Partial least squares (PLS) is a very popular regression method in application of Vis-NIR spectroscopy. In this study, PLS regression combined with spectral pre-processing such as derivative, standard normal variate transformation (SNV), multiplicative scatter correction (MSC) and smoothing was used to develop calibration models. PLS analysis was carried out to determine the optimal set of wavelengths and to develop calibration models using the statistical software Unscrambler. Calibration models were compared using the root mean squared error of calibration (RMSEC), root mean squared error of prediction (RMSEP), and correlation coefficients (r2) for calibration and validation. A good model should have a low RMSEC, a low RMSEP and a high r2 value. The calculation of RMSEC indicated how well the model fits the calibration data, and the parameter of RMSEP was reported as an indication of the model validation capability. RMSEC and RMSEP were calculated based on the following formulas:
RMSEC =
2
1 IP ⎛ ∧ ⎞ ⎜ yi − yi − bias ⎟ ∑ I P − 1 i =1 ⎝ ⎠
RMSEP =
bias =
1 IC ⎛ ∧ ⎞ ⎜ yi − yi ⎟ ∑ I C − 1 i =1 ⎝ ⎠
1 IP
∑ ⎛⎜⎝ y − y ⎞⎟⎠ IP
i =1
(1)
2
(2)
∧
i
(3)
i
Where: IC--- number of samples in the calibration set; IP --- number of samples in the ∧
validation set; sample;
yi ----- measured value of the ith sample; yi ----- predicted value of the i th
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3.2 Calibration and Validation Models Table 1 shows the PLS models results of different pre-processing methods and spectral ranges. The best wavelength range was from 450 to 1800 nm, which was wider than the other two wavelength ranges (450~1000 nm and 1000~1800 nm). It covers the visible and NIR spectral regions. Comparing the results in table 1, it shows that the optimal PLS model is obtained in the range of 450-1800nm and by the spectral data preprocessing method of SNV. For calibration, the correlation coefficient r2 and the RMSEC is 0.8514 and 0.8017 respectively. For validation, the correlation coefficient r2 and the RMSEP is 0.8514, and 1.1649 respectively.
Table 1. PLS models results of different pre-processing methods and spectral ranges
Wavelength Range/nm 450~1800
450~1000
1000~1800
Spectral Pre-processing Factors Method SNV FD SD MSC Smoothing SNV FD SD MSC Smoothing SNV FD SD MSC Smoothing
17 7 6 18 19 13 5 6 14 13 14 7 5 14 15
Calibration
Validation
r2
RMSEC
r2
RMSEP
0.9349 0.8556 0.7885 0.9397 0.9315 0.8875 0.8044 0.7634 0.9020 0.8894 0.8857 0.8889 0.8854 0.8853 0.8728
0.8017 1.1941 1.4452 0.7718 0.8224 1.0587 1.3900 1.5287 0.9840 1.0451 1.0627 1.0475 1.0639 1.0644 1.1209
0.8514 0.8063 0.6972 0.8434 0.8305 0.7739 0.7924 0.7056 0.8000 0.7691 0.8471 0.7634 0.5272 0.8475 0.8505
1.1649 1.3302 1.6630 1.1960 1.2443 1.4372 1.3772 1.6340 1.3514 1.4524 1.1819 1.4700 2.0780 1.1804 1.1684
Figure 3 shows the calibration result using PLS and SNV spectral pre-processing in the wavelength range of 450-1800nm for 185 intact navel oranges with a calibration correlation coefficient r2 of 0.8514 , a RMSEC of 0.8017 and figure 4 shows the validation result for the left 85 samples with a validation correlation coefficient r2 of 0.8514, a RMSEP of 1.1649. As the error that happened in chemical test and instruments, the result of validation was not good enough, so the next step research is to change the method to improve the predict capability. It was concluded that Vis-NIR reflection method yields a satisfied estimate of sugar content value in intact navel orange.
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Fig. 3. The optimal model of the calibration set
Fig. 4. The optimal model of the validation set
4 Conclusions This research indicated that it is possible to develop a nondestructive method for measuring the navel orange sugar content by Vis-NIR spectroscopy. The results showed that the PLS model developed from 450-1800nm spectroscopy after SNV pre-processing method achieved the optimal performance. The correlation coefficient (r2)of the optimal model of the calibration set and validation set were 0.9349 and 0.8514 respectively and root mean squared error of calibration and root mean squared error of validation were 0.8017 and 1.1649 respectively. It can be concluded that
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VIS/NIR spectroscopy could be a reliable, accurate, and fast method for measurements sugar content of navel orange.
Acknowledgement This work was supported in part by the National Natural Science Foundation of China (No. 30760101), Jiangxi Provincial Department of Science and Technology (No. 2009BNB05705) and Jiangxi Provincial Department of Education (No.GGJ08513).
References 1. Yu, X., Liu, M., Cheng, R.: A Study on Non-destructive Measurement of Nectarine Sugar Content by Means of Spectral Imaging. Acta Agriculturae Universitatis Jiangxiensis 29(6), 1035–1038 (2007) 2. Qing, Z., Ji, B., Shi, B., et al.: Improving Apple Fruit Quality Predictions by Effective Correction of Vis—NIR Laser Diffuse Reflecting Images. Spectroscopy and Spectral Analysis 28(6), 1273–1277 (2008) 3. Zhao, J., Zhang, H., Liu, M.: Non-destructive determination of sugar contents of apples using near infrared diffuse reflectance. Transactions of the CSAE 21(3), 162–165 (2005) 4. Zhao, J., Zhang, H., Liu, M.: Preprocessing Methods of NearInfrared Spectra for Simplifying Prediction Model of Sugar Content of Apples. Acta Optica Sinica 26(1), 136–140 (2006) 5. Zhu, D., Yu, D., Zhang, D.: A Quick and Non-destructive Measurement of Soluble Solids Content of Apple Based on Visible/Near Infrared Spectroscopy. Jinghua College of Vocation and Technology 9(6), 37–41 (2009) 6. Liu, Y., Luo, J., Chen, X.: Analysis of Soluble Solid Content in Nanfeng mandarin fruit with Visible Near infrared spectroscopy. J. Infrared Millim. Waves 27(2), 119–122 (2008) 7. Lu, H., Fu, X., Xie, L., Ying, Y.: Estimation of Soluble Solids Content of Intact Citrus Fruit by Vis/NIR Spectroscopy. Spectroscopy and Spectral Analysis 27(9), 1727–1730 (2007) 8. Zhao, J., Guo, Z., Chen, Q., Lü, Q.: Feasibility Study on Use of Near-Infrared Spectroscopy in Quantitative Analys is of Catechins in Green Tea. Acta Optica Sinica 28(12), 2302–2306 (2008) 9. Li, Q., Huang, Y., Zhang, G., et al.: Chlorophyll Content Nondestructive Measurement Method Based on Vis/NIR Spectroscopy. Spectroscopy and Spectral Analysis 29(12), 3275–3278 (2009) 10. Liu, K., Cheng, F., Lan, H.: Visible/NIR Analysis of Fat, Protein and Water in Chilled Pork. Spectroscopy and Spectral Analysis 29(1), 102–105 (2009) 11. Lu, W., Yuan, H., Xu, G., et al.: Modern Near Infrared Spectroscopy Analytical Technology, pp. 35–37. China Petrochemical Press, Beijing (2007) 12. Peng, Y., Lu, R.: Analysis of spatially resolved hyperspectral scattering images for assessing apple fruit firmness and soluble solids content. Postharvest Biology and Technology 48, 52–62 (2008) 13. Sánchez, N.H., et al.: Robustness of models based on NIR spectra for sugar content prediction in apples. Near Infrared Spectrosc. 11, 97–107 (2003)
Numerical Simulation of Temperature Field in Selective Laser Sintering Jian Zhang, Deying Li*, Jianyun Li, and Longzhi Zhao Key Laboratory of Ministry of Education for Conveyance and Equipment, East China Jiaotong University, Nanchang 330013, China [email protected], [email protected], [email protected], [email protected]
Abstract. The laser sintering process of multi-component powder W/Cu is simulated by ANSYS software based on the factors of radiation, convection and thermal physical parameters on temperature. The laser power and scanning velocity which are the key process parameters to affect directly in sintering molding are studied in paper. The results show that when the scanning velocity is constant, the sintering depth is rising with the increase of laser power; In addition, when the laser power is constant, the sintering depth is decreasing with the increase of scanning velocity. To select reasonable processing parameters and meet the requirements of sintering quality on the sintering depth, the parameters of laser power and scanning velocity are optimized by analyzing the sintering depth. Keywords: Selective laser sintering, Numerical simulation, Temperature field, Sintering depth.
1 Introduction W/Cu composite, a typical two-phase pseudo alloy, exhibits excellent electrical conductivity and thermal conductivity of Cu and high melting point and high hardness of W. It can be used as electrical contact and electrode material, military material for special purpose (such as rocket nozzle), and heat sink substrate with high air tightness packing of CPU and solid-state microwave tube, etc. So W/Cu composite has been widely used both in industry and military [1, 2]. Selective Laser Sintering (SLS), which becomes a research focus recently, can manufacture directly the metal mold or parts prototype with the complex shape from 3D CAD model, to obtain the functional parts meeting the requirements. For the advantages of short manufacturing cycle, wide range of materials and others, SLS is expected to obtain the W-Cu components with high density and complex shape that other process is difficult to do. In this paper, the temperature field distribution of W-Cu mixed powder is studied by ANSYS numerical simulation, and the effects of laser *
Corresponding author. Tel.: 13707096493.
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power and scanning velocity on sintering depth are analyzed. The reasonable processing parameters are selected by sintering depth, which has great significance for the sintering process of W-Cu mixed powder.
2 Establishment of Model 2.1 Establishment of Mathematic Model The molten pool has heat change with the surrounding air and powder bed in SLS, and the thermal conduction can be expressed by equation (1) [3].
∂T 2 ∂T 2 ∂T 2 ∂T ke ( 2 + 2 + 2 ) + qc + qg = ρC ∂x ∂y ∂z ∂t
(1)
Where k e is effective thermal conductivity of powder; ρ is compacted density of powder; C is heat capacity of material; qc is dispersed heat to air; q g is laser power density. Assume that the initial temperature T0 of powder bed is evenly distributed before sintering, and the initial condition is shown as follows:
T ( x, y, z, t ) t =0 = T0
(2)
In order to simplify calculation, assume that there is no heat loss on the bottom of substrate. In SLS, there is heat dissipation by convection and radiation, the boundary condition is shown as follows.
− ke
∂T ∂z
z=0
+ h(T − TE ) + σε(T 4 − TE4 ) = q
Where k e is effective thermal conductivity of powder; coefficient;
(3)
h is heat convection
T is temperature of metal powder at a certain moment; σ is
Stefan-Boltzmann constant; TE is initial temperature;
ε is heat radiation coefficient of
actual objects. 2.2 Establishment of Physical Model In order to simplify the sintering model and reduce the computing time, the finite element model is established in Fig. 1. The multi-component powder consist of W and Cu with a certain percentage, the size of which is 3.4mm×1.6mm×0.3mm. To ensure
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the enough mesh density in laser heating zone and heat affected region and reduce time, the different meshing sizes can be adopted to the substrate and sintered layers. The meshing of sintered layers is smaller (0.1mm), while the meshing of substrate is larger. The Gaussian energy distribution of laser is shown in Figure 2, the laser energy of center is the highest, and the laser energy is continuously reduced away from the spot center. The laser spot is divided into 4 × 4, as shown and the decay coefficients of 1, 2, 3 are 0.8359552, 0.5226424, 0.3267576[4].
Fig. 1. Finite element model
Fig. 2. Gaussian energy distribution of laser
In the sintering process, the laser energy obeys the Gaussian distribution.
q= Where q is laser power density;
2 AP
πϖ 2
exp( −2
r2
ϖ2
)
(4)
p is laser power; A is absorption rate of powder bed to
laser; r is distance between any point on the powder bed and laser spot center;
ω is
radius of laser spot.
3 Results and Analysis
℃
℃
The powder consists of W and Cu with a certain percentage, the melting points are 3380 and 1083 , and the other thermal physical properties on temperature are shown in Table 1 and Fig. 3. The process parameters to simulate that the spot diameter is 0.4mm, the scanning spacing is 0.3mm, the powder thickness is 0.1mm, the convection coefficient of air is 10, the effective radiation coefficient of powder bed is 0.8. Table 1. Thermal physical properties of Cu
℃
T/
-1
C/J(kg·k) K/W(m·k)-1
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100
200
400
500
600
800
1000
385 405
388 404
392 399
400 379
409 355
414 342
420 329
445 313
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(a) Specific heat capacity
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(b)Thermal coefficient
Fig. 3. Thermal physical properties of W
Fig. 4 shows the effects of scanning velocity on pool depth. As seen from it, when the laser power is constant, the sintering depth is decreasing with the increase of scanning velocity. The sintering depth is 0.29mm at v=0.12m/s, while only is the sintering depth 0.076mm at v=0.20m/s. The reason is that when the laser power is constant and the scanning velocity is increasing, the input laser energy decreases. Meanwhile, the time that energy on the powder particles is decreasing. Especially at high scanning speed, the contact time between energy and powder particle is very short, even the powder particles could not be melt for the energy transfer around the powder particles without enough time. But the temperature is rising quickly at low scanning speed, which leads easily to greater heat accumulation effect, and results in larger temperature gradient. The effects of laser power on pool depth are shown in Fig. 5. As seen from it, when the scanning velocity is constant, the sintering depth is rising with the increase of laser power. The sintering depth is only 0.08mm at p=195w, and the sintering depth is
Fig. 4. Effects of scanning velocity on pool depth Fig. 5. Effects of laser power on pool depth
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increasing to 0.21mm at p=235w. The reason is that when the scanning velocity is constant and the laser power is increasing, the output energy density is rising. But the excessive laser power makes the temperature so high that the powder layers have a greater contraction, and is easier to warping and cracking. The laser power and scanning velocity are the key process parameters to affect directly in sintering molding. The higher scanning velocity can not only effectively suppress the expansion of molten pool and the phenomenon of "splashing", but also improve the forming efficiency. The reasonable laser power can not only ensure the layers bond well, but also reduce the contraction and warping. The sintering depth must be greater than the powder thickness, to ensue the adjacent layers bond well by penetrating the current layer. Otherwise the adjacent layers will be separated, and the poor strength and accuracy of forming will be obtained, even the forming could not be completed. Fig.6 shows the temperature distribution of Z-direction at different time with a certain laser power and scanning velocity. As seen from it, the temperature of 0.1mm is obviously higher than the melting point of Cu (1356K) at t=0.05875s, it indicates that the sintering depth is greater than the powder thickness. Similarly, the sintering depth are about 0.14mm and 0.19mm at t=0.11125s and t=0.21125s, so the powder thickness is less than the sintering depth. At the current process parameters, the related joint between the first layer and substrate is strong, and the metallurgical bonding of layers is well. The 3D parts in SLS are completed by lines to surface and layer by layer overlapped, and the following two conditions should be met to form solid structure by sintering [5, 6]. 1) The degree coverage of energy should be required between scanning beams, that is, the scanning velocity could not be too high with a certain power density, ensure that the enough power input to make the powder in the current layer bond together and form the 2D surface structure without loose powder. 2) The powder thickness is less than the sintering depth, that is, the laser power should ensure the adjacent layers bond well by penetrating the current layer to form the 3D body structure.
Fig. 6. Temperature distribution of Z-direction at different time (1-t1=0.05875s, 2-t2=0.11125s, 3-t3=0.21125s)
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4 Conclusion 1) When the scanning velocity is constant, the sintering depth is rising with the increase of laser power; In addition, when the laser power is constant, the sintering depth is decreasing with the increase of scanning velocity. 2) To select reasonable processing parameters and meet the requirements of sintering quality on the sintering depth, the parameters of laser power and scanning velocity are optimized by analyzing the sintering depth. Acknowledgement. This work was sponsored by Science and Research Foundation of East China Jiaotong University (01308013), the Natural Science Foundation of Jiangxi Province (09497, 2009GQC0014, 2008GZC0037) and Graduate Innovation Foundation of East China Jiaotong University (YC09C002).
References 1. Liu, T., Fan, J.L., Tian, J.M.: Synthesis and Sintering of Ultra-fine/nanometer W-10%Cu Composite Powder. Journal of Central South University (Science and Technology) 40(5), 1235–1239 (2009) 2. Gu, D.D., Shen, Y.F.: Microstructures of Laser Sintered Micron/nano-sized Cu-W Powder. Acta Metallurgica Sinica 45(1), 113–118 (2009) 3. Zhang, W.X., Shi, Y.S., Li, J.G.: Simulation of Temperature Field for Optimization of Processing Parameters of Selective Laser Melting Metal Powders. Applied Laser 28(3), 185–189 (2008) 4. Ma, L., Huang, W.D., Yu, J.: Parametric Finite Element Model of Temperature/stress Field Evolution by Metal Laser Solid Forming. Chinese Journal of Laser 36(12), 3227–3232 (2009) 5. Kumar, S., Chatterjee, A.N., Saha, P.: An experimental design approach to selective laser sintering of low carbon steel. Journal of Materials Processing Technique 136(1/3), 151–157 (2003) 6. Tolochko, N.K., Mozzharov, S.E., Yadroitsev, I.A.: Selective laser sintering and cladding of single-component metal powders. Rapid Prototyping Journal 10(2), 88–97 (2004)
Numerical Simulations of Compression Properties of SiC/Al Co-continuous Composites Mingjuan Zhao, Na Li, Longzhi Zhao, and Xiaolan Zhang School of Mechanical and Electrical Engineering, East China Jiao tong University, NanChang 330013, China [email protected], [email protected], [email protected], [email protected]
Abstract. The numerical simulations of property of SiC/Al co-continuous composites under compression with ANSYS software were carried out. Based on the simulation results, deformational behavior and distribution of stress and strain fields were analyzed. The effects of compression speed for material property was studied. The results showed that Al matrix and SiC reinforcement exhibit different mechanical behavior, large deformation appears inside Al matrix; the configuration of SiC has relatively great influence on intensity and distribution of stress within composites, its ultimate stress occurs near the interface of composites; when an external force is exerted on the composites, Al matrix and SiC reinforcement restrict each other to prevent from producing the strain; With the increase of loading velocity, the stress of matrix and the strain of reinforcement increase rapidly. Keywords: Composites, Compression properties, ANSYS, Loading velocity.
1 Introduction With the fast development of research and applications technology of metallic matrix composite, the study on its macroscopical performance has to be paid increasing attention. The new composites have metal as a toughening phase and three dimension solid net framework structure as reinforcement, it has become the future trends of metallic matrix composites [1, 2]. The reinforcement of composites shows three-dimensional network structure, the distribution of holes is usually homogenized, and porosity is controllable [3]. The spatial topological structure has a number of special features, such as, light weight, high specific modulus and specific Strength, abrasion resistance, fatigue resistance, thermal shock resistance, and low coefficient of thermal expansion and so on. It has wide prospect to be applied in various industrial fields, such as aircrafts, automobile, electronics and machinery [4, 5]. In this article, the compression performance of SiC/Al Co-Continuous Composites was simulated by the finite element analysis software ANSYS.
2 Creating the Calculation Model of Composite Material When the compressive property of composites was simulated, we made some assumptions, an assumed equal division in the holes of SiC foam ceramics, ribs have D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 480–485, 2011. © IFIP International Federation for Information Processing 2011
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continuity and size is same; SiC is absolutely continuous distribution in the composite materials; The physical characteristics of the SiC and Al have the properties of isotropy; There is a suitable interfacial bonding between reinforcement and matrix, it belongs to mechanical bond, that is, it depends mainly on mechanical forces of rough surface of reinforcement and contractile force of matrix which wrap up reinforcement and create friction, the forces combine reinforcement and matrix, other impurities is nonexistent at the interface.
Fig. 1. Macro-appearance of SiC /Al Co-Continuous composites
Fig. 2. The simulated model of SiC/Al Co-Continuous composites
The model of SiC/Al Co-Continuous Composites should be preprocessed before numerical calculation. The primary attribute of SiC reinforcement is defined, elasticity modulus is 450Gpa, Poisson ratio is 0.17, density is 2.4 g/cm3, yield limit is 14 Mpa, shear modulus is 192.3 Mpa. Unit Type of reinforcement is defined as solid65. The primary attribute of Al matrix is defined, elasticity modulus is 24Gpa, Poisson ratio is 0.34, density is 0.6 g/cm3, yield limit is 7.6 Mpa, shear modulus is 80 Mpa. Unit Type of matrix is defined as solid45. In order to describe accurately the parameter changes, 16 stacked cells are adopted in numerical simulation. The macro-appearance and simulated model of SiC/Al Co-Continuous Composites are respectively showed in Fig.1and Fig.2.
3 Analysis of Simulation Result There is different Mechanical behavior between reinforcement and matrix to metal matrix composite materials. Simulation result of an intercepted cell was analyzed. The isopleths about displacement, stress and strain of the model are showed in Fig 3~8. This paper analyzes entire deformation, difference of elasticity modulus of two constituents cause difference of generated deflection. It can seems from Fig.3, Al matrix in the hole of SiC foam has taken place large deformation, SiC plays a supporting role, the stress mainly distributed in SiC foam. SiC has a clean and distinct outline in Fig.4 and Fig.5. Reinforcement has three-dimensional connected structural characteristic in the composite materials, and reinforcement and matrix have continuity. When an external force is exerted on the composites, Al matrix and SiC reinforcement restrict each other to
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prevent from producing the strain; Furthermore, stress distribution has relatively uniform in the center of the interface stress, essentially the stress value is constant; but stress go up tremendously in near the interface boundary, the maximum stress appear in the interfacial boundary or edge.
Fig. 3. Isopleths of Y-direction
Fig. 4. Isopleths of stress
Fig. 5. Isopleths of strain
Additionally, according to the Fig 7~8 which described the isopleths of stress and strain in the different working face, analysis of structure of SiC foam shows that the structure leads to the distribution of stresses has symmetry, so it has a very significant effect on the distribution and size of stresses. The maximum stress occurred at the interfacial boundary between SiC reinforcement and Al matrix. This is also caused by mechanical properties of the reinforcement and matrix, such as, elasticity modulus, yield stress, it is only normal for them to have differences. When an external force is exerted on the composites, the different deformation causes the uneven stress distribution in materials, and furthermore, the deformation behavior of material shows a great difference in near interface of two constituents. This is caused due to the three-dimensional connected structural characteristic, the force on each rib affects other adjacent rib, and stress intensity is related to ribbed-orientation, as well.
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Fig. 6. Diagrammatic sketch of working plane
(a)
(b)
Fig. 7. Isopleths of stress and strain (Working plane 1)
(a)
(b)
Fig. 8. Isopleths of stress and strain (Working plane 2)
To sum up, the three-dimensional connected structural characteristic has changed the distribution of stresses of composites, which can restrict the extraneous stretch or compression, and this structural has immensely heightened the tensile strength or compression strength. Moreover, the degree of stress concentration shows that a suitable interfacial bonding can improve the material performance.
4 Influence of Loading Velocity on Compression Deformation Behavior When temperature keep the constant, loading velocity is determined value, the deformation rate-time curve is shown in Fig.9. It can be seen from the graph that as the time is reduced the deformation rate increases, and the trend of deformation reducing slow down, material shows a higher deformability.
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Fig. 9. Deformation rate-Time curve
Fig. 10. 1-Stress-Speed curve of reinforcement 2-Strain-Speed curve of matrix
Based on the information provided by the Fig.10, with the fast loading velocity growth, the stress of reinforcement and the strain of matrix are all increase, the strength of composites is also increases. Strength has been mentioned is manifested by material in the static compression. It can be seen in Fig.10 that value of stress increases slowly with loading velocity raises, microcosmic principle is provided by engineering material can help to explain this, dislocation glide and plastic deformation need time, however, strain rate is too fast and there's not enough time to occur glide, so that materials exhibit rigid. Furthermore, loading velocity is too high, stress suddenly becomes more volatile causes the lower fracture toughness. In the paper perfect state is simulated, assumption has been made in previous paper, but it is difficult to obtain in the material fabrication processes, once the materials have microscopic imperfection, the fast pressure will exacerbate the breakdown speed of composites.
5 Conclusion 1) There is different Mechanical behavior between SiC and Al, difference of elasticity modulus of two constituents occasion difference of generated deflection, Al has taken place large deformation; 2) Due to structural characteristic of SiC, the force on each rib affects other adjacent rib; 3) When an external force is exerted on the composites, Al and SiC restrict each other to prevent from producing the strain; 4) With the fast loading velocity growth, the stress of reinforcement and the strain of matrix are all increase; the strength of composites is also increases.
References 1. Wang, S.H., Geng, H.R., Wang, Y.Z., Sun, B.: The Fabrication Method and Research Progress of the Reticulated Ceramic Reinforcement in Metal Matrix Composites. Materials of Mechanical Engineering 29(12), 1–3 (2005) 2. Zhang, Z.J., Wang, F.C., Yu, X.D., et al.: Research Status of Reticulated Ceramic/Metal Composite. Material Journal 23(1), 20–23 (2009)
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3. Wang, S.R., Geng, H.R., Wang, Y.W., Hui, H.: Model of Compressive Strength of 3DNSRMMCS. Acta Material Composite (23), 7–11 (2006) 4. Qin, S.S.: Metal-matrix Composites for Marine Applications: Development Status and Our Countermeasures. Material Journal 7(10), 68–70 (2003) 5. Yao, J.P., Wang, W.W., Ma, X.S., Yang, M.S.: Wear Behavior of Ceramics Network Composites Fabricated by Die Casting Method. Materials of Mechanical Engineering 39(1), 93–96 (2003)
Simulation and Optimization in Production Logistics Based on eM-Plant Platform XinJian Zhou, XiangBin Xu, and Wei Zhu School of Mechatronics Engineering, East China Jiaotong University, 330013 Nanchang, P.R. China [email protected]
Abstract. The optimization of production logistics system is an important way to improve enterprise’s productivity, cut down cost and improve equipment’s utilization. Production logistics system is highly randomized, complicated and discrete system, which can hardly be modeled and analyzed in the traditional way, so computer simulation technology and eM-Plant simulation platform were introduced in the paper to model and analyze production logistics system, more than modeling eM-Plant also can analyze production logistics system’s equipment’s utilization, working efficiency, production capacity statistics effectively, which can offer useful guideline for production logistics system optimization and scientific decision-making. Keywords: Production logistics, eM-Plant, Simulation, Optimization.
1 Introduction Production logistics should feature characteristics such as continuousness, smooth, parallel, proportionality, balance, flexibility, but many enterprises has production logistics problem including low productivity, more WIPs, long production cycle and waste of resources. The computer simulation technology is a effective way to find and solve these problems, the article takes eM-Plant simulation software to set up X4105BC diesel engine’s production logistics and optimize simulation models, the simulation and verification can offer great decision making support for the assembly line’s production logistics optimization, which ensure the scientific management decisions.
2 The Assembly Line’s Production Logistics 2.1 Process Route The X4105BC diesel engine is the main product of some manufacturing enterprises, the product mode of X4105BC diesel engine is in a multi-variety, small batch and D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 486–493, 2011. © IFIP International Federation for Information Processing 2011
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make-to-order way. The whole Diesel assembly process includes 22 procedures, which is listed in Table.1. Table 1. X4105BC diesel engine assembly route No
Procedure
No
Procedure Flywheel
No 15
Procedure Rocker
1
Crankshaft
8
2
Cylinder
9
Oil Pan
16
Gears Lid
3
Piston and Rod
10
Starter and Generator
17
4
Flywheel Cover
11
Cylinder Lid
18
Nozzle and Cylinder Cover Exhaust Pipe
5
Oil pipe
12
Water Pump and Pipe
19
Water Manifold
6
Oil Cooler
13
20
Pulley Wheel
7
Left Side Cover
14
High-Pressure Oil Pump and Air Filter Gears and Intake Manifold
21
Oil Filter
2.2 Production Lline Layout X4105BC diesel engine assembly line was built on a 108m-long non-power roller conveyor belt, the layout of the assembly line shown in Fig.1.
Fig. 1. The layout of the assembly line
3 Production Logistics Simulation Model 3.1 Assembly Line Simulation Bbased on eM-Plant Based on the X4105BC diesel engine process route and assembly line layout, the simulation model of the Assembly Line X4105BC build in eM-Plant is showed in Fig.2.
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Fig. 2. The eM-plant simulation model of X4105BC assembly line
In the simulation model, the assembly buffers are modeled in EM-plant’s Buffer component, the Capacity property of the EM-plant’s Buffer can specify buffer maximal number parts which can accommodate; the workstations are modeled in EMplant’s ParallelProc component, the set-up and processing time property of the EMplant’s ParallelProc can specify the workstation’s setting-up and processing time; EM-plant’s WorkerPool component is used to model worker dispatching,EM-plant’s Broker component can set worker dispatching rules, witch can route worker from the WorderPool to the right workstations. 3.2 The Simulation Results by eM-Plant Once the assembly line’s simulation model is completed, run the simulation model, eM-plant can offer many kinds of statistics table and chart for us to analyze and optimize. Here we take the workstation’s working balance histogram to analyze the workstation working load, which is show in Fig.3.The blue heap in the workstation’s working balance shows one worker’s total working time, the red heap in the workstation’s working balance mean balance lost of the assembly line. Fig 3. tells us than the there is huge balance loss in the assembly line, which results in waste of resources and time, and the assembly line must be optimized.
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7 6 5 4 3 2 1 0
489
Balance Lost Working Time1 Working Time1
1 4 1_ 1_
3
6
9
12
15 \19 18
Fig. 3. Assembly Line Balance Histogram
4 The Optimization and Simulation of Production Logistics 4.1 Assembly Line Process Route Optimization After field investigation based on the eM-plant simulation results, we decomposition working procedures1 and divide it into 5 sub-working procedures, namely working procedures1,2,3,4,5. since working procedures 18,19 and 20,21 are completed by a workers, so we combine working procedures 18,19 and 20,21 into one. The assembly process route after adjustment is shown in Table 2. Table 2. X4105BC diesel dngine assembly route after optimization No
Procedure
No
Procedure
1
Body Washed by Machine
9
Oil pipe
10
Cylinder Oil Cooler
11
Left Side Cover
2 3
Body Washed by Hand Camshaft Cushion
4
Camshaft Bush
12
Flywheel
5
Camshaft
13
Oil Pan
6
Cylinder
14
Starter and Generator
7
Piston and Rod
15
Cylinder Lid
8
Flywheel Cover
16
Water Pump and Pipe
No 17
18 19 20 21 22 23 24
Procedure High-Pressure Oil Pump and Air Filter Gears and Intake Manifold Rocker Gears Lid Exhaust pipe Nozzle and Cylinder Cover Exhaust pipe and Pulley Wheel Pulley Wheel and Oil Filter Return Oil Pipe
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And the assembly sequence after Optimized is shown in Fig.4.
Fig. 4. X4105BC’s assembly sequence diagram after optimization
4.2 Simulation Model After Optimization After adjustment and optimization the assembly route includes 24 working procedures, which are divided into four workstations, each workstation need only one operating workers to complete assembly tasks. The optimized simulation model shown in Figure 5, 6,7,8,9.
Fig. 5. X4105BC’s assembly eM-Plant simulation model after optimization
Here the “Source” means diesel engine supply; “Line” means powered conveyor which transfer diesel engine between workstations, Drain means the completion of the assembly line, gzz1, gzz2, gzz3 and gzz4, means the four workstation after optimization respectively. Workstation 1 include six working procedures, which are first wash, second wash, camshaft bushes, crank watts, crankshaft, cylinder. The Source1, Source2, Source3 mean the required component supply, the eM-plant simulation model of the Workstation 3 shown in Fig.6.
Fig. 6. eM-Plant simulation model of workstation1 after optimization
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Workstation2 include six working procedures, which are piston, flywheel, oil pipes, cooler, side cover, flywheel and other six processes, the eM-plant simulation model of the Workstation 3 shown in Fig.7.
Fig.7. eM-Plant simulation model of workstation2 after optimization
Workstation3 include six working procedures, which are oil pan, starter motor, cylinder head, water pump, high pressure oil pump diesel filter, how the gear into the trachea, the eM-plant simulation model of the Workstation 3 shown in Fig.8.
Fig. 8. eM-Plant simulation model of workstation3 after optimization
Workstation4 includes six working procedures, which are the arm rings, gear cover, injector cylinder covers, exhaust pipe, pulleys oil filter, oil pipes, the eM-plant simulation model of the Workstation 4 shown in Fig.9.
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Fig. 9. eM-Plant simulation model of workstation4 after optimization
4.3 Simulation Results After Optimization Once the optimization simulation model is completed, run the simulation model, we can get the interesting statistics after the simulation, hear we take the workstation’s working balance as an example. After the optimization, the workstation’s working balance histogram is shown in Fig.10. The blue heap in the workstation’s working balance histogram means all processing time for each workstations, the red heap means the total balance loss, it is clearly that after optimization,the assembly line’s balance lost is improved greatly and the working procedures processing is in a proportional way, which can lead a effective drop-down WIPs. 32 30 28 26 24 22 20 18 16 14 12 108 462 0
n1 n2 n3 n4 io io io io t t t t a a a a St St St St rk rk rk rk o o o o W W W W
Balance Working Working Working
Lost Time6 Time5 Time4
Working Time3 Working Time2 Working Time1
Fig. 10. Assembly line balance histogram after optimization
After optimization, the number of workers in the assembly line can be cut down largely, and the worker’s working efficiency has greatly improved from 65.41% to 96.19% on the average. And also, the WIP’s number and occupation rate in each buffer has greatly reduced from 65.834 to 9.024 on the average, which speeds up the enterprise’s logistics working efficiency greatly.
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5 Conclusions Many enterprise are facing production logistics problem such as WIP controlling, long production cycle ,low working efficiency and devilry delay etc, Handling these problem always means production mode adjustment which results in production line shutdown and assembly line re-balance, this may bring enormous loss if not handled carefully and rightly. With professional simulation software such as eM-Plant,we can build production logistics simulation model in a modular, hierarchical way, eM-Plant ‘s simulation mode and it’s statistics, data analysis and optimization capabilities can offer powerful support to for enterprise’s decision making.
Acknowledgements This study was supported by JiangXi Natural Science Foundation(No.2009GZS0015), JiangXi Educational Committee Foundation(No.GJJ10467), National High-tech Research and Development Program of China(863 program) (No. 2009AA04Z106) and Jiangxi Key Laboratory of Ministry of Education for Conveyance and Equipment.
References 1. Liu, G.-F., Ma, T.: EM-Plant-Based Washing Machine Assembly Line Balancing Analysis. Industrial Engineering and Management 3(200), 104–108 2. Ma, Y., Zhang, W.: Simulation Based Job Shop Scheduling Optimization. System Simulation 19(200), 4548–4552 3. Zhao, B., Cheng, Y.: Sedan Production Line Assembly Process Planning Simulation System. System Simulation 3, 198–203 (2003) 4. Cao, W., Zhu, Y.: Mixed model general assembly of dynamic programming and simulation. Computer Integrated Manufacturing Systems 4, 123–126 (2006) 5. Zheng, S.: Production Line Simulation Technology. Weapon Industry Automation (4), 22– 23 (2004)
Simulation of Transient Temperature Field in the Selective Laser Sintering Process of W/Ni Powder Mixture Jiwen Ren, Jianshu Liu, and Jinju Yin The School of Electromechanical Engineering, East China Jiaotong University, Nanchang, 330013, P.R. China [email protected]
Abstract. Selective laser sintering (SLS) is an attractive rapid prototyping and manufacturing (RP&M) technology as well as two-component metal powder has high melting pointer, high mechanical properties and high wear resistance. Hence, it’s meaningful to analyze its temperature field distribution and dynamical evolution rule in sintering process. A three-dimensional transient finite element model of SLS on the two-component metal powder W/Ni has been developed to predict the temperature field distribution in this paper. The dynamically loading of the moving Gaussian laser thermal resource was realized using the element “birth and death” technology and the ANSYS Parameter Design Language (APDL) in the model. Considering comprehensively thermal convection and the non-linear behavior of material properties etc., the temperature evolution of SLS process has been simulated effectively. The interrelation between the temperature field distribution and the processing parameters are analyzed. The sintering width and depth under certain selected sintering parameters are obtained so as to judge the metallurgical bonding performance between substrate and layers. The result of simulation can provide the theoretical basis for selecting reasonable processing parameters. Keywords: Selective laser sintering, Finite element simulation, Temperature field, Molten pool.
1 Introduction Selective laser sintering(SLS) is an attractive process in the new field of rapid prototyping (RP) which is such an advance manufacturing technology that integrates laser technology, precision machinery, computer-aided design, computer-aided manufacturing, computer numerical control, control technology, and material technology [1]. Direct metal laser sintering (DMLS) is a method of rapid prototyping and manufacturing (RP&M) which three-dimensional parts are formed directly from metal powders. It includes three major materials such as single-component metal powder, multicomponent metal powder and pre-alloyed powder. Multi-component powder can overcome the shortcomings of the single-component metal powder such as difficult forming, which consists of two metal materials with significantly different melting D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 494–503, 2011. © IFIP International Federation for Information Processing 2011
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points. The low melting metal powder acts as the bonding phase while the high melting metal powder acts as the framework phase [2]. Research shows that multicomponent metal could reduce plastic deformation in the high temperature and improve mechanical properties of the SLS parts [3]. Therefore, the research on direct laser sintering high melting metal powder has attracted more and more attention. Nowadays, many scholars at home and abroad work on SLS temperature field simulation [4-6], but there is little research on temperature field simulation of twocomponent metal powder with high melting point. Therefore, it’s necessary to systematically analyze the temperature field distribution and the dynamical evolution rules in sintering process of two-component metal powder and carries out accurate simulation and prediction, which can provide the theoretical basis and guidance to experiments of direct laser sintering high melting point metal powder. With the development of computer technology and finite element theory, it has becomes a reasonable way to study the laser sintering temperature field using finite element method (FEM). In this paper, a finite element model for laser sintering has been developed and the load of moving heat source at different times and locations is carried out by ANSYS Parametric Design Language (APDL). At the same time, the formation and evolution of transient temperature field sintering two-component metal powder during SLS and formation mechanism of two-component metal powder has been discussed.
2 Establishment of Model 2.1 Establishment of Finite Element Model The finite element model of sintering is shown in Fig. 1. The established finite element model is divided into two parts, namely substrate and powder. The Upper of model is two-component metal powder which is a mixture of W and Ni and its size is 3.4mm×1.6 mm×0.2 mm. The substrate material is 45 steel and its size is 4.4 mm×3mm×0.6 mm. In order to ensure the accuracy of the calculation, the sintering powder is meshed by Solid70 with hexahedral and eight-node and the grid size is 0.1mm×0.1 mm×0.1 mm while the substrate is meshed by Solid90. To save calculation time and improve efficiency, the larger grids are applied to the substrate.
Fig. 1. 3-D finite element model of laser sintering
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2.2 Initial Conditions and Boundary Conditions SLS is a very complex heat treatment process, which is accompanied by three ways of heat transfer including heat conduction, heat convection and heat radiation [7]. Before solving the heat balance equation, we should assume that powder bed has a uniform initial temperature T0 , which is at room temperature or reaches a certain uniform temperature through preheating, then the initial conditions as follows:
T ( x, y, z, t ) t =0 = T0 .
(1)
The convection and radiation between surrounding environment and substrate and the boundaries of powder bed belong to the third type boundary condition, which is expressed as follows.
− ke
∂T ∂z
z=0
+ h(T − TE ) + σε(T 4 − TE4 ) = q .
(2)
Where k e is the thermal conductivity of the material, h is convection heat transfer
coefficient, T is the temperature of metal powder at a certain moment, σ is the Stefan–Boltzmann constant, TE is initial temperature and ε is thermal emissivity of real object.
3 Load of Gauss Heat Source In the process of sintering, laser energy moving at a certain rate is input to powder bed in the form of heat flux. Generally speaking, the laser energy below 3kw obeys the Gaussian distribution [8].
q( x, y) = Where
2 AP
πω 2
exp(−2
r2
ω2
).
(3)
q( x, y ) is laser power density, ρ is laser power, A is absorption rate of
powder bed to laser,
r 2 = ( x − x0 ) 2 + ( y − y 0 ) 2 is distance between any point on
the powder bed and laser spot center and ω is radius of laser spot. In order to make this simulation close to reality, it needs to use the technique of “element birth/death” to exert the heat load at different times at different spots. First, all the element of powder bed is killed in the beginning. Then, the element which needs to be loaded is activated as the sintering goes on, which is used to simulate dynamic sintering process. Next, the heat flux is exerted on the activated element meantime in the meantime the heat flux of last load step should be removed and the
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previous solution results are used as the initial conditions for this solution to calculate thermal conductivity matrix and specific heat matrix. The circle is in turn until the whole sintering process completed.
4 Thermal Physical Properties of Material The sintering powder is obtained by mixing W powder and Ni powder according to the percentage of 55% Ni and 45% W. The material parameters of Ni ,W and the substrate material of 45 steel are shown [9,10]. The equivalent thermal physical parameters of mixture powder such as density and specific heat can be determined by the law of Kopp-Neumann. Among all the thermal physical parameters which have great influence on the performance of powder sintering, the effective thermal conductivity of powder bed is the most important. However, due to the heat transfer mechanism is complex, the precise value is difficult to determine. So the area without sintering cannot be directly defined with thermal physical properties of material, but could be estimated by the following equation [11].
⎡ ϕk ⎤ ke = (1 − 1 − ϕ ) ⎢1 + r ⎥ + 1 − ϕ × kg k g ⎥⎦ ⎢⎣ ⎡ ⎢ ⎢ 2 ⎢ kg ⎢1 − ⎣⎢ k s
⎤ ⎛ ⎞ ⎜ ⎟ ⎛ k s ⎞ ⎟ k r ⎥⎥ ⎜ 1 . ln⎜ ⎟ − 1 + ⎜ k g ⎜⎝ k g ⎟⎠ ⎟ k g ⎥ ⎜⎜ 1 − ⎟⎟ ⎥ ks ⎥⎦ ⎝ ⎠
Where k g is the thermal conductivity of environment,
(4)
k s is effective thermal con-
ductivity of solid, ϕ is initial porosity and k r is heat transfer coefficient of powder bed cased by radiation, which can be expressed by the following equation.
kr
σ
4F T 2 D p .
(5)
D p is average diameter of powder particles, T is temperature of powder particles and F is apparent coefficient approximately
Where
is Stefan-Boltzmann constant,
taken as 1/3.
5 Simulation Results and Discussion Fig. 2 shows the scanning pattern of simulation. It includes two layers. Each layer has five scanning paths and the scanning width is 0.3mm. The other simulation parameters
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include the laser power, the spot diameter, the scanning speed, the thermal absorptivity, the initial temperature and the coefficient of air convection under normal temperature. The values are 300W, 0.4mm, 80mm/s, 0.3, 298K and 10, respectively. In order to master the variation of temperature field in sintering process, some special points on scanning line are selected to analyze, as shown in Fig. 2. Among which point 1, point 2 and point 3 is the midpoint of line 1, line 2 and line 5, respectively. And the mid-point of the first scanning path of the second layer is marked as point 4.
Fig. 2. Scanning pattern of laser sintering
,
,
Fig. 3 shows the temperature distribution at time 0.0125S 0.025S 0.0375S. As seen from Fig. 3, With the moving of laser beam the temperature field distribution is different from distribution of rotundity temperature field of stationary laser beam. The concrete expression is that the isotherm of the sintered front-end is closer than that of the sintered area, namely, temperature gradient of the sintered front-end is greater than that of sintered area. The reason is that with the rapidly moving of the highenergy laser beam the heat of laser center spreads around during the sintering process. While the density and thermal conductivity of sintering area are higher than them of powder front-end, thus heat is more easily to spread backward and makes the distance of isotherm of the sintered area enlarge and the temperature distribution exhibit “comet” shape. The simulation results show that zone affected by heat expands constantly and the temperature of substrate and powder bed has increased to some extent as the sintering goes on. This is mainly due to the accumulation of heat during sintering process. Fig. 3 shows that the temperatures of molten pool have exceeded the melting point of Ni(1728K) while the maximum temperatures of molten pool fail to reach the melting point of W (3650K). Therefore, Ni powder has change into liquid while the W powder keeps on solid phase. It has ensured that the molten pool formed by solid-liquid mixture state. The solid particles of the molten pool dissolved in the liquid phase rearrange, move closer to each other and bond into the frame by the role of liquid surface tension. The remaining liquid evenly distributes in the gap of the skeleton, which avoids effectively the "balling" phenomenon of sintering in pure liquid phase.
Simulation of Transient Temperature Field in the SLS Process of W/Ni Powder Mixture
(a) at 0.0125S.
(b) at 0.025S.
(c) at 0.0375S. Fig. 3. Temperature distribution at different moment
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Fig. 4 is the temperatures of point 1, point 2 and point 3 vary with time. When point 1 is sintering, its temperature rises rapidly to 2628K and exceed the melting point of Ni, so the Ni powder melts. Its temperature gradually reduces when the spot’s far away and there’s a similar fluctuation with the increase of scanning lines. For sintering two layers and each layer with five scanning, temperature of every point has about 10 similar fluctuations. Moreover in each layer, with the distance between scanning path and point 1 increasing, fluctuation gradually decline, namely, the effect on the temperature of point 1 decrease gradually. In the meantime the highest temperature of subsequent scanning path is little higher than that of previous scanning path, and it has the similar regularity to other points. Fig. 4 shows that the temperatures of point 1, point 2 and point 3 show upward trends throughout all the sintering process, which is due to heat accumulation caused by sustained action of laser beam. Fig. 5 is the temperatures of point 1 and point 4 vary with time. Point 4 is the midpoint of the first sintering path of the second layer. While sintering the first layer, the element of point 4 has been killed, so the temperature of point 4 is still the initial temperature (298K) at the time 0.19375S. While sintering the second layer, the temperature of point 4 rises gradually. when the laser beam scans through point 4, the temperature of point 4 sharply rises to near 3000K and the temperature of point 1, under point 4, correspondingly rises, which is lower than point 4 because of separating a sintering layer and higher than melting point of Ni. The sintering depth is more than 0.1mm, which shows that these process parameters ensure the metallurgical bonding between layers as well as the bonding strength between layers of sintered parts.
Fig. 4. Temperatures of point 1, point 2 and point 3 varying with time
Fig. 5. Temperatures of point 1 and point 4 varying with time
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Fig. 6 is the temperature distribution of Y-direction and Z-direction of point 1 and point 2. From Fig. 6(a), we could see the width of point 2, above the melting point of Ni powder (1728K), is about 0.425mm,which is larger than sintering width(0.3mm) and ensures the metallurgical bonding between scan paths. Fig. 6(b) shows that the temperature has decreased with the increase of depth of sintering, the temperature at 0.1mm has reached the melting point of Ni powder, which shows that the powder of sintering layer could be melt completely and makes sintering layer and the substrate are bonding firmly. The temperature distribution of point 1 is similar to that of point 2, except for the temperature of point 2 is little higher than point 1 because of the heat accumulation. Compared Fig. 6(a) with Fig. 6(b), we can find that temperature gradient of Y-direction is larger than that of Z-direction, hence, the heat lose is mainly along Z-direction. So it is necessary to find out the influencing factors of the depth of molten pool, which are adjusted to stabilize the molten pool and improve the precision of parts.
(a) Temperature distribution of Y-direction.
(b) Temperature distribution of Z-direction. Fig. 6. Temperature distribution of point 1 and point 2
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6 Conclusion Considering comprehensively the influence of temperature-related thermal physical properties, Gaussian laser beam, thermal conduction and heat convection etc., a finite element model of SLS on the two-component metal powder has been developed using APDL and the temperature field has been simulated effectively using the element “birth and death” technology and the dynamical loading of the moving laser beam, which could dynamically reflect the form and change of temperature field during sintering process. The results show that the highest temperature during sintering process is higher than the melting point of Ni powder, but not reaches the melting point of W powder, so the sintering mechanism is an incomplete molten mechanism, Which is also consistent with forming mechanism of SLS powder mixture. The heat accumulation makes the area affected by heat expand and the whole temperature of substrate and powder bed rise as sintering goes on. It’s reasonable to select SLS process parameters according to the width and depth of the molten pool.
Acknowledgements We are thankful that the study is supported by Natural Science Foundation of Jiangxi Province of China(2008GZC0055) and Foundation of Jiangxi Educational Committee(GJJ09209).
References 1. Wang, R.J., Li, X.H., Wu, Q.D.: Optimizing process parameters for selective laser sintering based on neural network and genetic algorithm. Int. J. Adv. Manuf. Technol. 42, 1035– 1042 (2009) 2. Xiong, B.W., Xu, Z.F., Yan, Q.S., et al.: Progress on metal powder materials used for direct selective laser sintering. Hot Working Technology 33(9), 92–94 (2008) (in Chinese) 3. Cui, Y.J., Bai, P.K., Wang, J.H., et al.: The present application and materials for selective laser sintering. New Technology & New Process 4, 74–77 (2009) (in Chinese) 4. Kolossov, S., Boillat, E., Glardon, R., et al.: 3D FE simulation for temperature evolution in the selective laser sintering process. International Journal of Machine Tools & Manufacture 44, 117–123 (2004) 5. Guo, H.F., Zhou, J.Z., Zeng, Z.R.: 3D finite simulation for temperature field of direct metal laser sintering. Tool Engineering 40(1), 13–18 (2006) (in Chinese) 6. Zhou, J.Z., Guo, H.F., Xu, D.P., et al.: Finite element simulation for the temperature field in multi-layer thin-wall metal part formed by DMLS. China Mechanical Engineering 18(21), 2618–2623 (2007) (in Chinese) 7. Gu, D.D., Shen, Y.F., Liu, M.C., et al.: Numerical simulations of temperature field in direct metal laser sintering process. Transactions of Nanjing University of Aeronautics & Astronautics 21(3), 225–233 (2004) 8. Weng, M.C., Yang, Z.Q., Guo, H.F., et al.: Effect of process parameters on the temperature field evolution of Fe Powder laser sintering. Laser Journal 28(3), 70–72 (2007) (in Chinese)
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9. Yang, J., Wang, F.: 3D finite element temperature field modeling for direct laser fabrication. Int. J. Adv. Manuf. Technol. 43, 1060–1068 (2009) 10. Tan, Z., Guo, G.W.: Thermal physical properties of engineering alloys. Chinese Standards Press, Beijing (1988) (in Chinese) 11. Shen, Y.F., Gu, D.D., Li, S.W., et al.: Simulation of 3D transient temperature field during selective laser sintering of multi-component metal powder. Journal of Nanjing University of Aeronautics & Astronautics 40(5), 611–615 (2008) (in Chinese)
Study on Plant Nutrition Indicator Using Leaf Spectral Transmittance for Nitrogen Detection Juanxiu Hu1, Dongxian He1,*, and Po Yang2 1 Key Lab. of Agriculture Engineering in Structure and Environment, College of Water Conservation and Civil Engineering, China Agricultural University, Beijing, P.R. China [email protected] 2 Beijing Lighting valley Technology Company, Beijing, P.R. China
Abstract. The low fertilizer utilization at growing season and environment pollution coursed by unreasonable fertilization are becoming global outstanding problems in agricultural production. Scientific and reasonable fertilization based on rapid and nondestructive plant nutrient detection will be a valuable solution for solving above problems. In this study, spectral transmittance in wavelength ranged from 300 to 1100 nm, chlorophyll content and nitrogen content of rice and cucumber leaves treated with culture solution in five different nitrogen levels were measured. According to the correlation analysis between them, 560, 650, and 720 nm as feature wavelengths and 940 nm as reference wavelength were determined for nitrogen detection. Correlation analysis between 21 spectral feature parameters composed by the transmittance at above wavelength, the leaf chlorophyll content and nitrogen content, and combined with their regression examination indicated that spectral feature parameters of (T940 - T560) / (T940 + T560), log (T940/T560) and log (T940/T650) are useful to conduct plant nutrient diagnosis with less than 8% relative error in rice and cucumber leaves. Therefore, the above spectral feature parameters as plant nitrogen indicators can be used to estimate the chlorophyll content and nitrogen content, furthermore support for non-destructive plant nutrient detection and fertilizer recommendation based on testing soil. Keywords: Chlorophyll content, Nitrogen content, Spectral feature parameter, Spectral transmittance.
1 Introduction Nitrogen is an essential nutrient factor for growth and quality of plants. The applying of nitrogen fertilizer has been growing persistently in order to increase the crop yield. However, the environmental pollutions caused by low seasonal utilization of nitrogen fertilizer and the unreasonable applications of chemical fertilizer have become outstanding issues in agricultural production [1, 2]. The amount of nitrogen in soil is closely related to the nitrogen nutrition status of plant. The scientific nitrogen fertilization based on evaluating nitrogen nutrition status of plant is an effective approach to solve the problem above. *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 504–513, 2011. © IFIP International Federation for Information Processing 2011
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Chlorophyll content and nitrogen content are important indications for evaluating nitrogen nutrition status of plant. Estimating chlorophyll content and nitrogen content by methods of chemical analysis though presenting reliable results, cannot meet the requirement of guiding fertilizer promptly because of the vary complicated and time-consuming process [3]. The application of remote sensing technology in agriculture has provided a new means for rapid and non-destructive diagnosis of plant nitrogen nutrition [4]. There are lots of studies focusing on diagnosis of plant nitrogen nutrition based on the spectral properties of plant were carried out. Spectral reflectance of plant leaves in the vicinity of 550 and 670 nm were highly relevant to chlorophyll and nitrogen contents by measuring the reflectance of leaves or canopy [5, 6]. Reflectance in 550 nm and 710 nm could be used to better estimate the nitrogen content in corn and R(550~600) / R(800~900) could be sensitive to reflect the nitrogen stress in corn. The linear combinations of reflectance in 620 and 760 nm had good correlation with nitrogen contents in rice leaves [7]. As to studies on plant spectral transmittance and nitrogen nutrition, an in-vivo detection device was developed for estimation plant chlorophyll content based on the difference in leaf spectral transmittance between in 660-690 nm and in 760-1100 nm [8]. Spectral characteristic parameter log (I660-690/I760-1100) was adopted in the device to estimate leaf chlorophyll content, in which I660-690 and I760~1100 were the intensity of light within corresponding wavebands having transmitted through leaves. Minolta, a Japanese company, then improved the algorithm and developed a portable chlorophyll meter. The spectral feature parameter adopted in the meter was log (T940/T650), namely, SPAD (Soil and Plant Analysis Development) value, in which T940 and T650 were the transmittance in corresponding wavelengths. The portable chlorophyll meter has been widely applied in rapid and non-destructive diagnosis of nitrogen nutrition in rice, maize, wheat, cotton and other field corps [9-12]. It also had a good performance in application for horticultural plants and xylophyta such as sweet potato, rape, peach, and maple, etc [13-16]. Many studies have been conducted on nitrogen nutrition diagnosis with the plant reflection spectrum, while the research on plant spectral transmittance is mostly based on the application of the portable chlorophyll meter. In this study, the feature band in direct relation with nitrogen nutrition of plants was determined based on transmittance spectra of rice and cucumber leaves cultivated in nutrient solution of different levels of nitrogen fertilizer. The correlation analysis and regression estimation error analysis were carried out of established spectral feature parameters and chlorophyll content as well as nitrogen contents, so as to determine plant nutrition indicators for nitrogen detection through estimating chlorophyll content and nitrogen content in leaves.
2 Materials and Methods 2.1 Cultivation of Plants In this study, the cultivation of plants were performed in a environment controlled greenhouse using cucumber (Cucumis sativus L., cv., Zhongnong No.8 and Beijing 203) and rice (Oryza sativa L., cv., Wuyujing No. 3) as model plant during the period from 2008 to 2009. Cucumber and rice seedlings were transplanted to 5 cultivation
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beds of the same dimension (250 cm × 60 cm × 40 cm), and 16 plants in each bed. A homogenous mixture of vermiculite, grass peat and perlite at a proportion of 3:1:1 was used as the cultivation base. The temperature and light intensity in greenhouse were optimumly controlled through pad and fan cooling system and sunshade screen.
Fig. 1. The status of cucumber and rice cultivation
Cucumber and rice plants were treated with culture solution in 5 different nitrogen levels. With the nitrogen level of nutrient solution formulation for cucumbers from Yamazaki Japan as 100%, content of nitrogen in the nutrient solutions were increased or decreased by 50% and 100% respectively while content equality of other major nutrient elements was ensured as far as possible (Table 1). Then the growing areas, according to the different nitrogen levels, were marked as N0, N50, N100, N150 and N200. The pH of culture solution was adjusted to 6.5-7.5. Pumps and timers were applied in automatic timing irrigation of the nutrient solution. Table 1. Nutrient solution in different treatments for cucumber and rice cultivation
Ca(NO3)2·4H2O CaCl2·2H2O KNO3 KCl KH2PO4 NH4H2PO4 NH4NO3 MgSO4·7H2O
N P K Ca Mg
The content of chemical in nutrient solutions (Unit: mg L-1) N0 N50 N100 N150 N200 0 0 826 826 826 516 516 0 0 0 0 607 607 607 607 370 0 0 0 0 136 0 0 0 0 0 115 115 115 115 0 0 0 280 560 483 483 483 483 483 The content of major nutrient elements (Unit: mmol L-1) N0 N50 N100 N150 N200 0 7 14 21 28 1 1 1 1 1 6 6 6 6 6 3.5 3.5 3.5 3.5 3.5 2 2 2 2 2
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2.2 Measured Parameters and Measurement Methods During the tillering stage of rice and fast growth period of cucumber, five samples of plant leaves in each treatment area were selected respectively for parameters measurement of the spectral property and nitrogen nutrition indices, including the spectral transmittance of leaf within the wavelength range of 300-1100 nm, and the chlorophyll content and nitrogen content of leaf. (1) The determination of spectral transmittance Spectral transmittance of rice or cucumber leaves was determined using an integrating sphere measurement device in the large sample chamber of spectrophotometer (UV3150, Shimadzu Co., Japan). The measurement wavelength range was 300-1100 nm with the interval of 1nm. The light source switch point was set at 360 nm and the raster switch point at 820 nm while the slit width was 20 nm. The measurement position was basically in both sides of the main vein and middle of the leaf. For each leaf, 4 different positions were selected for determination of spectral transmittance, so each leaf was measured for 4 times. (2) The determination of chlorophyll content 0.05g rice leaves (0.20g cucumber leaves) were weighed, cut into filaments and put into test tubes. After adding 10mL mixture of 1:1 ethanol-acetone, the tubes were placed in refrigerator at 4oC for 16-18h in the dark for extracting chlorophyll of leaves. The extract was uniformly shaken and then transferred into a clean cell for determination of chlorophyll content. With the ethanol-acetone (1:1) mixture as the reference, absorbance values at 663 and 645nm of the extract were measured by a spectrometer (UV3150, Shimadzu Co., Japan).The chlorophyll content was calculated by the correction formula of Arnon method [17]. (3) The determination of nitrogen content 0.10g rice or cucumber leaves were weighed to a 100mL digestion tubes and wetted with a little water dripped in, and then 4mL of concentrated H2SO4 was added. The tubes were covered with small curved neck funnels to place overnight after shaken gently. The next day, the tubes were put into a digestion furnace to heat firstly at 180oC for an hour, and then at 300oC for 2 hours. When the solution became brown-red, the tubes were moved away and cooled for 3min. Then 15 drops of 30% H2O2 were added into the solution. The tube was put into the digestion furnace to heat at 300oC again for 15 min after shaken. Then 10 drops of 30% H2O2 was added after the tubes were moved away to cool for 3min again. The above procedures were repeated for times with the amount of 30% H2O2 gradually decreased until the solution became colorless or bright. Finally, the tubes were heated for 20min in order to remove residual H2O2. After thoroughly cooled, the digestion solution was arranged on a Kjeldahl type automatic azotometer (KDY-9830, Beijing Tongrunyuan Electromechanical Technology Co., Ltd., China) for distillation titration to determine the nitrogen content. 2.3 Processing and Analysis of Data The mean value of four measurements of each leaf sample’s spectral transmittance within 300-1100 nm was adopted. The correlation analysis of the leaf spectral
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transmittance, the chlorophyll content, and the nitrogen content was conducted with the SPSS software, so as to determine the feature wavelength and reference wavelength for nitrogen nutrition diagnosis in plants. With the correlation analysis of spectral feature parameters established by the spectral transmittance of characteristic wavelength and reference wavelength, the leaf chlorophyll content, and the leaf nitrogen contents, plant nitrogen nutrition indicators were determined and tested.
3 Results and Analysis 3.1 The Spectral Transmission of Plant Leaves Spectral transmittances of cucumber and rice leaves were changed basically with the same trend of the wavelengths in different nitrogen nutrition levels. In the range of photosynthetically active radiation wave band (400-700 nm), the leaf spectral transmittance formed wave crest at 550 nm and shaped up wave trough at 680 nm. At the same time, the leaf spectral transmittance reduced with the increasing nitrogen. Spectral transmittances of leaves were all between 40~50% in near-infrared wave band (800-1100 nm), in which the range of variation was little. 50
50
b) Cucumber
40 N0 30
N50 N100
20
N150 N200
Transmittance (%)
Transmittance (%)
a) Rice 40
N0 N50
30
N100 N150
20
N200 10
10
0
0 300
500
700
Wavelength (nm)
900
1100
300
500
700
900
1100
Wavelength (nm)
Fig. 2. Leaf spectral transmittances of cucumber and rice leaves treated with culture solution in different nitrogen levels
The spectral properties of plant leaves are mainly formed by absorption, reflection and transmission of light towards mesophyll cells, chlorophyll, moisture content and other biochemical components in the leaves. In the wave band of 400-700 nm, the spectral properties of leaves were mainly affected by chlorophyll. Due to strong absorption of red light and little absorption of green light by leaf chlorophyll, a wave crest was formed around 550 nm while a wave trough of low transmittances around 680 nm in leaf spectral transmittance. In fast growth period of plants, with the increasing of fertilizer nitrogen, the chlorophyll and nitrogen content also increased so that leaves could absorb more light at 400-700 nm for photosynthesis, therefore spectral transmittance of plant leaves in this wave band decreased with the increasing of
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fertilizer nitrogen. In the near-infrared wave band (800-1100 nm), the spectral properties of leaves were mainly influenced by the tissue structure in leaves, while the impact of chlorophyll could be negligible. The spectral transmittance of leaf in the near-infrared wave band was 40-50%, which is in line with the results of plant leaf spectrum by other researchers referring to that the absorptivity of leaf was generally less than 10% and reflectivity was about 50% [18-19]. 3.2 The Correlation between Spectral Transmittance of Leaves and Chlorophyll Contents as well as Nitrogen Contents The significant negative correlation between spectral transmittance in the waveband of 500-720 nm and leaf chlorophyll content as well as nitrogen content was found in rice and cucumber leaves with the correlation coefficients ranging from -0.8 to -0.9 (P=0.01). Within the waveband of 900-1100 nm, there was not a significant correlation between spectral transmittance and chlorophyll content as well as nitrogen content.
0.8 0.6
1.0
a) LST and CC Rice (n=78) Cucumber (n=110)
0.4 0.2 0.0 -0.2 300 -0.4 -0.6
940
500
700 560 650 720
900
-0.8 -1.0
1100
Correlation coefficient
Correlation coefficient
1.0
0.8 0.6
b) LST and NC Rice (n=78) Cucumber (n=110)
0.4 0.2 0.0 -0.2 300
500
700
900
1100
-0.4 -0.6 -0.8 -1.0
Wavelength (nm)
Wavelength (nm)
Fig. 3. Correlation coefficient between leaf spectral transmittance (LST), chlorophyll content (CC) and nitrogen content (NC)
Integrated spectral feature parameters, such as difference value and ratio of spectral parameters between feature waveband and reference waveband were adopted in order to minimize the impact of structure and thickness of plant leaves on the spectral data analysis thereby enhancing the accuracy of estimations of chlorophyll and nitrogen content[6, 7]. For instance, spectral feature parameter of log (T940/T650) was used in the portable chlorophyll meter (SPAD-502) produced by Japanese company Minolta to estimate leaf chlorophyll content. A portable meter developed by Fuchigami et al for plant nutrient detection adopts T940/T560 and T940/T720 [20]. Based on the correlation between spectral transmittance and chlorophyll content as well as nitrogen content and relevant studies, 560, 650, 720 nm were selected as typical feature wavelengths in the 500-720 nm waveband, and at the same time 940 nm was chosen within the wave band of 900-1100 nm as the reference wavelength to establish 21 spectral feature parameters (Table 2) for nitrogen nutrition diagnosis of plants.
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3.3 The Correlation between Spectral Feature Parameters of Leaves and Chlorophyll Contents as well as Nitrogen Contents The spectral feature parameters the correlation coefficient between which and chlorophyll content in rice was over 0.94 (P=0.01) were as follows: T940/T560, (T940 - T560) / (T940 + T560), (1/T560 - 1/T940) / (1/T940), (T940 - T560) / T940, log (T940/T560), T940/T650, (1/T650 - 1/T940) / (1/T940), log (T940/T650). Moreover, the correlation coefficient between all spectral feature parameters mentioned above and nitrogen contents in rice was over 0.91 (P=0.01) (Table 2). The spectral feature parameters the correlation coefficient between which and chlorophyll content in cucumber was over 0.91 (P=0.01) were as follows: (T940 - T560) / (T940 + T560), log (T940/T560), (T940 - T650) / (T940 + T650), log (T940/T650). The correlation coefficient between the two former spectral feature parameters and nitrogen content in cucumber was 0.87 and 0.88 respectively, while that of the latter two and nitrogen content was over 0.90 (P=0.01). It was indicated that the spectral feature parameters of (T940 - T560) / (T940 + T560), log (T940/T560), and log (T940/T650) had a high correlation with chlorophyll and nitrogen contents in cucumber and rice. Table 2. Correlation coefficient between spectral feature parameters and chlorophyll content as well as nitrogen content
T940/T560 (T940- T560) / (T940 + T560) (T940 - T560) / T940 T940 - T560 - T940 × T560 (1/T560 - 1/T940) / (1/T940) log (T940/T560) log (T940/T560) / log (T940) T940/T650 (T940 - T650) / (T940 + T650) (T940 - T650) / T940 T940 - T650 - T940 × T650 (1/T650 - 1/T940) / (1/T940) log (T940/T650) log (T940/T650) / log (T940) T940/T720 (T940 - T720) / (T940 + T720) (T940 - T720) / T940 T940 - T720 - T940 × T720 (1/T720 - 1/T940) / (1/T940) log (T940/T720) log (T940/T720) / log (T940)
spectral feature parameter and chlorophyll content rice cucumber 0.94 0.90 0.95 0.91 0.94 0.90 0.92 0.89 0.94 0.90 0.95 0.91 -0.92 -0.88 0.94 0.89 0.91 0.91 0.90 0.90 0.76 0.78 0.94 0.89 0.94 0.92 -0.88 -0.89 0.90 0.86 0.90 0.86 0.90 0.86 0.89 0.85 0.90 0.86 0.90 0.86 -0.92 -0.84
spectral feature parameter and nitrogen content rice cucumber 0.93 0.87 0.92 0.87 0.91 0.87 0.88 0.86 0.93 0.87 0.93 0.88 -0.87 -0.84 0.92 0.87 0.89 0.90 0.88 0.89 0.71 0.76 0.92 0.87 0.92 0.90 -0.84 -0.88 0.88 0.81 0.88 0.81 0.88 0.80 0.87 0.80 0.88 0.80 0.89 0.81 -0.88 -0.78
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3.4 The Experimental Examination of Spectral Feature Parameters Linear regression analysis was carried out of spectral feature parameters, namely (T940 - T560) / (T940 + T560), log (T940/T560) and log (T940/T650), and chlorophyll as well as nitrogen contents in rice and cucumber measured by chemical methods. Chlorophyll and nitrogen contents were estimated through the regression formula and compared with the values measured practically (Table 3). It was found that the relative errors of chlorophyll and nitrogen contents in rice estimated by (T940 - T560) / (T940 + T560), log (T940/T560), and log (T940/T650) were below 5.4%. As regards to chlorophyll contents in cucumber, the relative errors were below 4.5%, and the relative error of its nitrogen content was less than 7.7%. These results indicated that the relative errors of estimated leaf chlorophyll and nitrogen contents with spectral feature parameters of (T940 - T560) / (T940 + T560), log (T940/T560), and log (T940/T650), could meet the requirements of testing the plant nitrogen nutrition in vivo. Thus, they are suitable for use indicators of plant nitrogen nutrition. Among the spectral feature parameters mentioned above, (T940 - T560) / (T940 + T560) was the same as was adopted in the plant nutrition detector developed by Fuchigami et al (2007) while log (T940/T650) was the same as used in the portable chlorophyll meter (SPAD-502) produced by Minolta Corporation. Table 3. Relative error of estimated chlorophyll and nitrogen content using spectral feature parameter (n=30)
(T940- T560) / (T940 + T560) log (T940/T560) log (T940/T650)
Relative error of estimated chlorophyll content (%) Rice Cucumber 5.3±3.7 4.4±3.5 5.2±3.7 4.5±3.5 5.1±3.7 4.5±3.9
Relative error of estimated nitrogen content (%) Rice Cucumber 5.2±3.4 7.6±5.0 4.7±3.0 7.7±5.0 5.4±3.4 6.5±4.6
4 Conclusions Spectral transmittance in wavelength ranged from 300 to 1100 nm, chlorophyll content and nitrogen content of rice and cucumber leaves treated with culture solution in five different nitrogen levels were measured. According to the correlation analysis between them, 560, 650, and 720 nm as feature wavelengths and 940 nm as reference wavelength were determined for nitrogen detection. Correlation analysis between 21 spectral feature parameters composed by the transmittance at above wavelength, the leaf chlorophyll content and leaf nitrogen content, and combined with their regression examination indicated that spectral feature parameters of (T940 - T560) / (T940 + T560), log (T940/T560) and log (T940/T650) are useful to conduct the plant nutrient diagnosis with less than 8% relative error in rice and cucumber leaves. Therefore, the above spectral feature parameters as plant nitrogen indicators can be used to estimate the chlorophyll content and nitrogen content.
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Acknowledgments. This work has been supported by National High Technology Research and Development Program of China (2006AA10A302) and (2006AA10Z206).
References 1. Zeng, X.B., Li, J.M.: Fertilizer Application and its Effect on Grain Production in Different Counties of China (in Chinese). Scientia Agricultura Sinica 37, 387–392 (2004) 2. Ju, X.T., Xing, G.X., Chen, X.P., Zhang, S.L., Zhang, L.J., Liu, X.J., Cui, Z.L.: Reducing Environmental Risk by Improving N Management in Intensive Chinese Agricultural Systems. Proceedings of the National Academy of Science 106, 3041–3046 (2009) 3. Jiao, W.J., Min, Q.W., Lin, K., Zhu, Q.K., Zhang, J.J.: Progress and Perspective on Nutrition Diagnosis of Plant Nitrogen (in Chinese). Chinese Agricultural Science Bulletin 22, 351–355 (2006) 4. Tian, Y.C., Zhu, Y., Yao, X., Liu, X.J., Cao, W.X.: Non-destructive Monitoring of Crop Nitrogen Nutrition Based on Spectral Information (in Chinese). Chinese Journal of Ecology 26, 1454–1463 (2007) 5. Thomas, J.R., Oerther, G.F.: Estimating Nitrogen Content of Sweet Pepper Leaves by Reflectance Measurements. Agronomy Journal 64, 11–13 (1972) 6. Filella, L., Serra, L., Penuelas, J.: Evaluating Wheat Nitrogen Status with Canopy Reflectance Indices and Discriminant Analysis. Crop Science 35, 1400–1405 (1995) 7. Shibayama, M., Akiyama, T.: A Spectroradiometer for Field Use VII. Radiometric Estimation of Nitrogen Levels in Field Rice Canopy. Japanese Journal of Crop Science 55, 433–438 (1986) 8. Watanabe, S., Kuzunuki, T.: Method of and Device for Measuring Chlorophyll of Living Leaves. Patent, Japan (1981) 9. Turner, F.T., Jund, M.F.: Chlorophyll Meter to Predict Nitrogen Topdress Requirement for Semidwarf Rice. Agronomy Journal 83, 926–928 (1991) 10. Wu, L.H., Tao, Q.N.: Nitrogen Fertilizer Application Based on the Diagnosis of Nitrogen Nutrition of Rice Plants (Oryza sativa L.) Using Chlorophyll Meter (in Chinese). Journal of Zhejiang Agricultural University 25, 135–138 (1999) 11. Piekielek, W.P., Fox, R.H.: Use of a Chlorophyll Meter to Predict Side-dress Nitrogen Requirements for Maize. Agronomy Journal 84, 59–65 (1992) 12. Follett, R.H., Follett, R.F.: Use of a Chlorophyll Meter to Evaluate the Nitrogen Status of Dryland Winter Wheat. Communications in Soil Science and Plant Analysis 23, 687–697 (1992) 13. Shaahan, M.M., EI-Sayed, A.A., Abou EI-Nour, E.A.A.: Predicting Nitrogen, Magnesium and Iron Nutritional Status in some Perennial Crops Using a Portable Chlorophyll Meter. Scientia Horticulturae 82, 339–348 (1999) 14. Chang, S.X., Robison, D.J.: Nondestructive and Rapid Estimation of Hardwood Foliar Nitrogen Status Using the SPAD-502 Chlorophyll Meter. Forest Ecology and Management 181, 331–338 (2003) 15. Li, H.Y., Ren, Q.P., Sun, S., Ma, H.Y.: Study on Relation between SPAD Value and Chlorophyll Contents in 10 Kinds Horticulture Woody Plants (in Chinese). Forestry Science and Technology 34, 68–70 (2009) 16. Su, Y.S., Guo, H.C., Yang, X.L.: Study on Correlations between SPAD Readings and Chlorophyll Content in Leaves of Sweet Potato, Dioscorea and Konjaku (in Chinese). Southwest China Journal of Agricultural Sciencea 22, 64–66 (2009)
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17. Lichtenthaler, H.K., Wellbuen, A.R.: Determinations of Total Carotenoids and Chlorophyll a and b Leaf Extracts in Different Solvents. Biochemical Society Transactions 11, 591–592 (1983) 18. Schepers, J.S., Blackmer, T.M., Wilhelm, W., Resende, M.: Transmittance and Reflectance Measurements of Corn leaves from Plants with Different Nitrogen and Water Supply. Journal of Plant Physiology 148, 523–529 (1996) 19. Bauerle, W.L., Weston, D.J., Bowdena, J.D., Dudley, J.B., Toler, J.E.: Leaf Absorptance of Photosynthetically Active Radiation in Relation to Chlorophyll Meter Estimates Among Woody Plant Species. Scientia Horticulturae 101, 169–178 (2004) 20. Fuchigami, L.H., Ding, P.H., Barnes, G.E.: Portable Meter to Measure Chlorophyll, Nitrogen and Water and Methods. Patent, USA (2007)
Study on the Influence of Non-electrical Parameters on Processing Quality of WEDM-HS and Improvement Measures Guangyao Xiong1, Meizhu Zheng1, Deying Li1, Longzhi Zhao1, Yanlin Wang1, and Minghui Li2 1
School of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang, Jiangxi, 330013, China 2 Department of Plastic Forming, Shanghai Jiaotong University, Shanghai, 200030, China [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
Abstract. The high-speed wire electrical discharge machining (WEDM-HS) machine has been more and more favoured by customers for the low manufacturing cost, the degree of automation and the advantages over the WEDM-LS in price performance ratio. However, the processing quality (the precision of form and position and the surface quality) of WEDM-HS is poorer than that of WEDM-LS, and the processing quality is one of the main technical indicators of WEDM. There are many factors on the processing quality of WEDM-HS, the effects of non-electrical parameters, including the machine precision, the wire-moving system and wire-moving way of the wire electrode and the working solution, on the processing quality of WEDM-HS are discussed, and the corresponding measures of improving the processing quality are put forward, which provide the sufficient basis for further improving the processing quality of WEDM-HS. Keywords: WEDM-HS, Non-electrical parameters, Processing quality, Improvement measure.
1 Introduction The wire electrical discharge machining (WEDM) is the method of EDM that the metal wire is used as tool-electrode [1]. In the processing, the anode of pulse power connects with the workpiece and the cathode connects with the electrode wire, the high-temperature generated by impulsive discharge between the workpiece and the wire electrode will make the workpiece melted and gasified to achieve processing, and the relative trajectory and velocity between them are controlled to cut out the workpiece with a certain shape and size. WEDM could be used to solve the processing problems of materials with special mechanical properties, such as high melting point, high hardness and ductility, and the parts will be with special structure and requirements, which are difficult or unsolvable for the traditional process. Therefore, it has the D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 514–520, 2011. © IFIP International Federation for Information Processing 2011
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utmost importance in mold, forming tool, unmanageable materials and complex precision parts. According to the moving way of wire electrode, WEDM machine can be divided into high-speed and low-speed CNC ones, which have great difference in structure and processing property [2, 3]. Because the various schemes are taken in the high-speed and the low-speed WEDM, which leads to much difference in the structure of machines, the wire-moving systems and processing conditions, it may not be very appropriate to make a comparison between the processing performances of two machines one by one. Excluding the factor of cost, the accuracy, functionality, reliability, and processing stability of the domestic WEDM-HS machine have large gap comparing with foreign advanced WEDM-LS technology. In this paper, the ways of improving the processing surface quality of WEDM-HS will be discussed from the influence of main non-electric parameters on processing quality.
2 Main Non-electrical Parameters on Processing Quality of WEDM-HS and Improvement Measure 2.1 Influence of the Precision of WEDM-HS on Processing Quality The precision of WEDM-HS is the primary condition to ensure the processing quality, and the precision of worktable is primarily decided by the precision of transmission parts (screw mandrel, nut and gear), the fit clearance, the equipping precision, and the work environment of machine et al. The processing quality is poor for the poor transmission precision of worktable. Therefore, the manufacturing precision of WEDM-HS should be strictly controlled to improve processing precision. 2.2 Influence of the Stability of Wire-Moving System on Processing Quality and Control Measures The flexible metal wire is used as the electrode in WEDM, which is carried out by the role of impulsive discharge between the workpiece and wire electrode. The wire electrode will be pushed away from the discharge area, and bended backward with a certain flexivity when the wire electrode is discharging. As shown in Fig.1, line 1 is the actual track of wire electrode, the processing direction of which is L1; line 2 is the theoretical track of wire electrode, and line 3 is the actual track of wire electrode, the processing direction of which is L3. Under the condition of limiting flexivity, the dynamic WEDM-HS process is always simplified to the static variation, and the bending section of the wire electrode is approximated as an arc, so the actual discharge point has deviated y cm from the theoretical cutting point, and the flexivity could be expressed as the following Eq.1 [1, 4].
y=
2 fL − fH 4F
(1)
Where y is the flexivity (cm); L is the span length of wire electrode (cm); H is the thickness of work piece (cm); f is the discharge force and F is the tensile force of wire electrode.
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The traditional wire cutting drives the wire electrode in V-groove of guide wheel to move back and forth through the rotation of guide wheel, the schematic diagram of guide wheel positioning as shown in Fig.2. The bearing ball is easy to wear, and produce the radial traverse for the speed of guide wheel is 8000 n/s, which makes the vibration of wire electrode [5]. The wire electrode moves generally back and forth with the speed of 10 m/s, as a result, the bottom of V-groove will be abraded, so the accurate positioning of wire electrode can not be guaranteed. When the cutting directions are changed, the direction of L1, L2, L3 and L4 as shown in Fig.1, the position of tangent point and the tension between wire electrode and guiding wheel are variable, resulting in the change of flexivity between y1 and y3. It is obviously that y1 is larger than y3, and y2 equals with y4. As the form and position of wire electrode changes, it is difficult to improve precision.
Fig. 1. Variations of form and position of wire electrode (1-Processing track along L3; 2-Theoretical track; 3- Processing track along L1)
Fig. 2. The positioning of guide wheel (1-Bearing; 2-Guide wheel; 3-Wire electrode; 4-Tangent point processing along L1; 5-Tangent point of theoretical track; 6-Tangent point processing along L3)
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The flexivity of wire electrode cased by the discharge power has no influence on processing precision when the straight line is cut, and the flaw is produced called sunken corner for processing the corner to influence the processing precision, the formation of sunken corner as shown in Fig.3, in addition, the vibration of wire electrode will inevitably produce the deviation of cylindricity when the cylinder is cut. Therefore, the form of spacial variations and the position of wire electrode should be steadied in order to reduce the accuracy error of wire electrode.
Fig. 3. The formation of sunken corner (1-Theoreti-cal track; 2-Actual track; 3-Wire electrode)
In order to reduce the flexivity and steady on the variations of form and position of wire electrode, two guiders with wear properties are adopted to position the wire electrode up and down by Shanghai Mass Electronic Equipment Co., Ltd. The wire electrode passes through the guider as shown in Fig.4, which is blocked by the small holes of guider. The aperture and diameter of wire electrode match reasonably, and the deviation cased by wire electrode is blocked by the small holes when the processing directions are changed, which is the four directions. As the guide device is installed, the actual distance L between two fulcrums up and down of wire electrode is decreased. According to the Eq.1, the flexivity is actually reduced. So the variations of form and position of wire electrode are inhibited and steadied, in order to further improve the stability of processing precision.
Fig. 4. The positioning of guiders with wear properties (1-Guiders; 2-Spray nozzle plate)
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2.3 Influence of the Movement Back and Forth of Electrode Wire and Working Solution on Processing Quality and Control Measures The workpiece surface processed by WEDM-HS will generally produce obvious stripes, when there is almost no stripe for WEDM-LS, it is decided by the cooling method and wire-moving way of WEDM-HS [6]. In WEDM-LS, the workpiece is immersed in de-ionized water to cool, and the wire-moving way is wire-moving one-way with low speed, while the rushing fluid is adopted to cool in WEDM-HS, the working solution is emulsion, and the wire-moving is instability to produce stripes inevitably, for the wire-moving way is wire-moving back and forth with high speed. The stripes of workpiece surface processed by WEDM-HS can generally be divided into two kinds, the one is the stripes with color, whose black and white concentration in the entrance and exit of wire-moving are different, and sometimes the kerf of exit side is slightly wider. The basic reason is the detergency of working solution. It is generally acknowledged that the stripes are caused by the rushing fluid and the dirty degree of working solution in entrance and exit. The other is the convex-concave stripes. When the wire electrode moves from top to down, the working solution is taken from the top into kerf along the wire electrode, and the discharge products are taken out in the processing zone from the bottom along wire electrode to accumulate at the exit of kerf, blocking the new working solution to come into kerf. So the insulated state of working solution is not normal at the exit of wire electrode, resulting in the abnormal discharge, and the kerf width of exit is less than that of the entrance as shown in Fig.5. When the wire electrode moves back and forth, the height of entrance and exit of wire electrode are different in the same surface, which will affect the processing precision and surface roughness of wire-cutting.
(a) Moving from top to down
(b) Moving from down to up
Fig. 5. Wire-cutting back and forth
The measures to reduce strips as follows: (1) To remove the black and white stripes, the saponification solution with strong detergency should be used as the working solution of WEDM, and the detergent state of kerf should be improved by adding some detergency substance. The spiral nozzle is used to spray, and the guiders with high wear properties mentioned above have reasonable spraying structure, making the working solution even eject along the axis of wire electrode.
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(2) The wire electrode of general WEDM-HS does not reverse until the entire wire go to end, in order to form the convex-concave stripes. The processing zone that the wire electrode passes through is longer, the convex-concave stripes are more obvious, whereas the stripes are few. When the electrode wire is short to a certain extent, the convex-concave stripes could be removed. In order to remove the convex-concave stripes, the key is to control the length of wire electrode in each direction and the repeated addition of cutting traces of wire electrode in processing zone, it’s to remove the convex-concave stripes. The wire-moving method of ultra-short trip back and forth is adopted by Shanghai Mass Electronic Equipment Co., Ltd. In order to achieve the cutting without strip, the actual cutting distance of reversing direction each time is very short, it’s about a quarter of the wire diameter, and the irregularities formed during the movement of wire electrode up and down are stacked with each other, so the black and white and convex-concave stripes will be difficult to find out. If the cutting path in reversing each time is shorter, the effect will be better. The wire-cutting technology of ultra-short trip back and forth dose not use the short molybdenum wire, which will lead to the short section of wire electrode long-term concentrated to accelerate the loss of wire diameter and break of wire, and affect seriously the processing precision. Although the storing wire cylinder rotates and reverses frequently, the whole cutting process is still performed with the full-length molybdenum wire of storing wire cylinder, in order to avoid the loss of wire diameter after the concentrated discharge effectively. However, the high-frequency pulse power is cut off frequently to reverses frequently the storing wire cylinder, which will affect the average cutting speed. 2.4 Influence of Residual Stress Inside the Workpiece on Processing Quality When the roughcast after heat treatment is processed by WEDM, due to the removal of much metal and interrupted cutting, the relative balance of residual stress inside the workpiece will be destroyed to reduce the processing precision of parts. Even the material will be suddenly cracked in the process of cutting, and the wire electrode is caught and pulled apart by kerfs in severe cases. Therefore, materials with excellent harden ability and small deformation of heat treatment should be chosen. In addition, the heat processing methods should be chosen correctly and the standards of heat treatment should be performed strictly.
3 Processing Quality The TP-25 WEDM machine produced by Shanghai Mass Electronic Equipment Co., Ltd. is used to process. The processing material is Cr12, which size is 10 mm×10 mm×40 mm. The processing condition and processing quality are shown in Table 1. The research results show that compared to the guide wheel to position and adopting the wire-moving of whole trip back and forth, the surface roughness value can be reduced 0.8 μm m, the maximum error of sunken corner can be reduced 10 μm m, and there is no reversing stripe using the guider with high wearing resistance to position and the wire-moving of ultra-short trip back and forth. So the processing quality of workpiece is greatly improved in spite of the decline of cutting speed.
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Sample
Position mode
01
By guide wheel
02
By guider
Wire-moving way Whole trip back and forth Ultra-short trip back and forth
Exist reversing strips or not
Surface roughness (μm)
Maxsunken corner (μm)
Processing time (s)
exist
2.4
17
3062
not
1.6
7
2125
4 Conclusion 1) The manufacturing precision of WEDM has great influence on the processing quality, and should be strictly controlled to improve machining precision. 2) The variations of form and position of electrode wire, producing inevitably in the process of WEDM-HS, which could be effectively controlled by the guiding device with high wearing resistance to improve the processing quality, if the wire-moving cutting method of ultra-short trip back and forth is applied to cut with no strips, however, the cutting speed will decline. 3) The strips could be reduced to improve the surface quality by using the working solution with the strong detergency and the appropriate spray method. Acknowledgment. Work was supported by the National Natural Science Foundation of China (Grant No. 10972030).
References 1. Li, M.H.: Theoretical basis of EDM (In Chinese). National Defence Industry, Beijing (1989) 2. Li, M.H.: The Research Status and Development Trend of Electric Discharge Wire-cutting Technology. Die and Mould Technology (6), 49–52 (2002) 3. Guo, L.E., Liu, Z.X., Xing, X.F.: Study on dynamic stability of multiple cut on machine tool in HS WEDM. Electromachining (6), 22–25 (1999) 4. Li, M.Q., Li, M.H., Xiong, G.Y.: Study on the Variations of Form and Position of the Wire Electrode in WEDM-HS. International Journal of Advanced Manufacturing Technology 5(9), 929–934 (2005) 5. Xia, W.F.: Electric Sparkle Cutting Bad Reasons for Product Quality and Prevention. Equipment Manufacturing Technology (7), 178–182 (2009) 6. Liu, Z.D.: Technology Research of WEDM Using Composite Cooling Liquid. Electromachining & Mould (12), 24–30 (2008)
Test Analysis and Theoretical Calculation on Braking Distance of Automobile with ABS Dongsheng Wu, Jun Li, Xiaoping Shu, Xiaojing Zha, and Beili Xu School of Mechanical and Electronic Engineering, East China Jiaotong University, Nanchang 330013, P.R. China
Abstract. Braking performance test methods are compared and analyzed. ABS will not work if the speed is too low when the automobile is tested by tester and load testing. Since the braking performance can not be evaluated accurately in this case, the theoretical calculation of braking distance is given in this paper. The calculation result shown the potential of braking performance is mainly on high speed for the automobile with ABS. High-speed road test is designed, and the test results are close to calculation ones, so calculation model is of accuracy. It is less error and better precision than existing calculation way, this method is effective and accurate. Keywords: Automobile with ABS, Testing, Braking distance, Theoretical calculation.
1 Introduction The ABS automobile is a vehicle with anti-lock braking system. The Braking performance reflects the ability that the vehicle stops in a short time and keeps traveling stability. The braking distance is the distance required for a vehicle moving at a specified velocity to come to a complete stop after its brakes have been activated. It is an important indicator for braking performance evaluation, but the error is big for braking distance test of automobiles with ABS[1]. So its performance can’t be accurately shown from test results[2]. Therefore, the ABS braking distance is simulated through this theory method. Simulation results must be compared with the road test to verify the simulation accuracy. For the road test of ABS brake performance, the United States, Japan and the European Economic Community, Economic Commission for Europe have enacted stringent norms and regulations, and also put forward specific requirements from different perspectives. By theoretical calculation, initial speed in these norms and regulations has been discussed whether it can truly reflect potential braking performance in the line brake. It can be more targeted to amend road test so that the braking performance of vehicle with ABS can be comprehensive evaluated[3-4].
2 Braking Distance Test of Automobile with ABS There are two methods for testing braking performance of automobiles with ABS, one is by tester and the other is by road testing. The brake distance can be measured by road D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 521–527, 2011. © IFIP International Federation for Information Processing 2011
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testing. At present, towing method is mainly used on the road testing, that is to say, the press and drag mark is used to evaluate the braking performance when a vehicle moving at a specified speed brakes. This method is simple and visual, but the disadvantage is also obvious. This method is limited by many factors such as weather, road, driver[5]. Test data is easily impacted on human and test condition. Therefore, the value is different after many tests and evaluation of braking performance is not exact.
3 Calculation Method of Braking Distance of Automobile with ABS In order to get reference for road test results, calculation equation is derived through analysis of braking process. 3.1 Establishment of Calculation Model The reaction time t0 mainly depends on the driver, as well as the positions of accelerator pedal and brake pedal. Usually, it only takes 0.3~1.0 seconds so the distance that the vehicle moves during t0 at the speed of v0 can be ignored according to equation s1 = v0 ⋅ t0 .
F' F0 δM 2 F0 − δ M F0 −
Fig. 1. Braking process of automobile with ABS
The second step is the growth of braking force t1. The braking force keeps increasing with the driver moving the brake pedal until it is up to the maximum. Due to the gap between brake shoe and brake drum, braking force will work after a short period of
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time. To compare the results with the one in Reference 6, this period can also be ignored. So the brake reaction time can be regarded as t1. At this period, the automobile’s braking performance is the best because of ABS working. Supposed the maximum braking force just reaches the maximum ground braking force, according to the force analysis of wheels during braking, the maximum deceleration F0 is as followed:
F0 = ϕ p ⋅ g ⋅ M
(1)
Where, φp is peak adhesion coefficient, g is acceleration of gravity, which is 9.8m/s2. During the growing step of braking force, the growth is a linear function of time, whose average braking force F1 is: T1
F1 =
∫ 0
mgϕ p T1 T1
dT =
1 mgϕ p 2
(2)
In this step, according to Newton's second law, the average deceleration a1 and terminal velocity v1 can be expressed as followed:
a1 =
F1 1 = gϕ p m 2 t1
v1 = v0 − ∫ 0
gϕ p
1 tdt = v0 − gϕ pt1 t1 2
(3)
(4)
According to the functional relationship, the work of braking force on the car is equal to kinetic energy increase before and after braking, so F1 is:
F 1 ⋅ S1 =
1 1 1 mgϕ p S1 = mv02 − mv12 2 2 2
(5)
Then braking distance of second step s1 is:
v02 − v12 S1 = gϕ p
(6)
The third step is braking duration. So pressure regulation frequency ω and amplitude δ are considered as design parameters, and pressure regulation process of ABS is
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simulated by cosine function, then coordinate is transformed (shown in Fig.1). The equations can be gotten as below:
δM
⎫ ⎪ 2 ⎪ δM ⎪ F ' = F − ( F0 − )⎬ 2 ⎪ ⎪ ⎪ t ' = t − t1 ⎭
F'=
cos ωt '
(7)
Eq.7 is converted to original coordinate system, as shown below:
F=M
d 2 S2 δ δ ⋅M = (F0 − ) + cos [ω (t − t1 ) ] 2 dt 2 2
(8)
Solving Eq.8, then it can get the braking distance of second step, so the total value is:
S = S1 + S 2
(9)
3.2 Initial Conditions and Solution of Model Initial conditions of Eq.8 are shown in Eq.10:
⎫ d 2S = a0 = gϕ p ⎪ 2 dt t =t1 ⎪ 2 2⎬ V − V1 ⎪ S (t1 ) = S1 = 0 gϕ p ⎪⎭
(10)
Table 1. Design parameter values road
σ
ω
dry concrete road wet concrete road
0.2647 0.3333
50 100
To braking requirements of ECE13 on the high friction coefficient road, initial braking speed is 50 km/h , and ABS braking performance is not significant[4] because it is difficult to find a complete cycle in this moment. Therefore, in Eq.10, for the
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high-speed braking situation, the initial velocity is respectively taken 100km/h and 130km/h. Simulated calculation is happened on the dry and wet concrete road, and the peak friction coefficient is respectively 0.9 and 0.8. t1 is the time of the brake force growth which depends on the speed of the driver stepped on the brake pedal and the brake system structure, generally, t1 is from 0.15s to 0.2s in hydraulic brake system, and is 0.3s ~ 0.9s[7] in air pressure brake system and the vacuum servo brake. 0.4s is taken in this calculation. Substitute related values in Eq.8, Eq.9 and Eq.10 and solve it, and the results are shown in Tab.2. Table 2. The brake distance simulation results on the dry and wet concrete road with high-speed braking calculation conditions concrete road Initial velocity(km/h) dry 100 wet 100 dry 130 wet 130
calculation results brake distance(m) 51.382 58.129 84.946 95.317
4 Road Test and Error Analysis 4.1 Road Test Verification By comparing the brake distance values which are recorded for a Benz car with ABS in Doc.8 through test road with results of using the calculation methods in this paper, the brake performance reliability for this car can be evaluated. Table 3. The brake distance values of the Benz car on concrete road at high speed [8]
test test condition ABS working ABS not working program concrete road Initial speed(km/h) Brake distance(m) Brake distance(m) 1 dry 100 41.832 50.1284 2 wet 100 62.753 100.1651 3 dry 130 81.264 93.7321 4 wet 130 97.125 138.23541 From Tab.3, it can be told that the brake distance test values are almost the same as the calculated values in this paper except the ones in Program 1, which tested on dry concrete road at an initial speed 100km/h. Under the some conditions, the brake distance results were calculated by the method mentioned in Doc.6. Comparing the tested results, the calculated results with the method in Doc.6 and the calculated values in this paper, Fig.2 can be obtained as below.
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Fig. 2. Brake distance results comparison
The results in Doc.6 were calculated in the condition that the brake system obtained the biggest brake force during continuous brake process with ABS. So ideal ABS model is called and the results should be smaller than the actual ones. Fig.2 shows that the calculated results are bigger than the ones of the ideal model except Program 1. Consequently, the brake distance calculation method in this paper is reasonable. 4.2 Error Analysis The error between the calculation result with the method in Doc.6 and tested results is calculated, and is compared with the error between the results from this paper and actual vehicle test. As shown in Fig.3, the calculation result error with the method in this paper fluctuates around the horizontal axis and tends to be smaller, whereas, the result error of Doc.6 tends to be larger. With the increasing of vehicle’s speed, the error brake distance error(%)
error between ideal model calculation and road test error between calculation in this paper and road test
22.83
13.54 4.53
O
dry 100km/h -14.84
7.64
0.36 -1.83 Road/Initial speed dry wet -7.35 130km/h 130km/h wet 100km/h
Fig. 3. Brake distance error comparison
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of this paper is rather stationary, and the calculation result is fairly reliable. However, the calculation result error with the method in Doc.8 is a litter larger. So the calculation result with the method in this paper is reliable and stable.
5 Conclusions 1. A calculation model of brake distance is come up, which showed that brake distance for ABS vehicles during continuous brake process is relevant to brake initial speed, road condition, ABS control system’s regulating frequency and amplitude. This calculation method can be applied to brake distance calculating and analyzing for various kinds of vehicles. 2. Comparing the brake distance calculation results in this paper with the results from actual vehicle road test, it can be concluded that the calculation in this paper is effective and accurate, which also can evaluated properly on the brake distance results in the test. 3. Evaluation is made on one road test. According to the calculation results in this paper, it can be gotten that the brake distance results of Program 1 are doubtful and need further confirmation.
Acknowledgement The work is supported by the Department of Transportation of Jiangxi Province (2009T0053).
References 1. Alvarez, L., Yi, J., Clarys, X., Horowitz, R.: Emergency braking control with an observer-based dynamic tire/road friction model and wheel angular velocity measurement. Vehicle Syst. Dun 39(2), 81–97 (2003) 2. Schinkel, M., Hunt, K.: Anti-lockbraking control using a sliding mode like approach. In: Proc. American Conf., Anchorage, AK, USA, vol. 3, pp. 2386–2391 (May 2002) 3. Song, J., Kim, H., Boo, K.: A study on anti-lock braking system controller and rear-wheel controller to enhance vehicle lateral stability. In: Proc. IMechE. Part D: J. Automobile Engineering, vol. 221, pp. 777–778 (2007) 4. Sugai, M., Yamaguchi, H., Miyashita, N.N.: New Control Techniaue for Maximizing Braking Force on Antilock Braking System. Vehicle System Dynamics 32, 299–312 (1999) 5. Liu, S.: Research of Bed-testing Evaluation Method of ABS Performance(Master thesis). Wuhan University of Technology, Wuhan (2006) 6. Wang, R.-q., Jiang, k.-j.: Analysis and Calculation of Braking Distance of ABS Automobiles. Journal of Central South Forestry University 25(2), 12–14 (2005) 7. Chen, J.: The:Theory and Practice of ABS Automobile. Beijing Polytechnic University Press, Beijing (1999) 8. Yu, Z.: Automobile Theory. Mechanical Industry Press, Beijing (2006)
The Detection of Early-Maturing Pear’s Effective Acidity Based on Hyperspectral Imaging Technology Pengbo Miao1, Long Xue2, Muhua Liu1,* , Jing Li1, Xiao Wang1, and Chunsheng Luo1 1
Engineering College, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, P.R. China 2 School of Mechanical and Electronical Engineering, East China JiaoTong University, Nanchang, Jiangxi 330013, P.R. China [email protected]
Abstract. The hyperspectral imaging technology is used to detect early-maturing pear’s effective acidity nondestructively, and effective prediction model is established. 145 pears’ hyperspectral images are obtained in the wavelength range of 400nm-1000nm. Total 145 pears are separated into the calibration set (77 samples) and prediction set (68 samples). Early-maturing pear’s effective acidity partial least squares (PLS) prediction model is built in different range of spectrum band. By comparison, the range 498 nm - 971 nm was selected in using partial least squares (PLS) to build early-maturing pear’s effective acidity prediction model. The experimental results show that, PLS prediction model of early-maturing pear’s effective acidity has the best effect in this range of wavelength. The correlation coefficient R between early-maturing pear’s actual effective acidity and predicted effective acidity is 0.9944 and 0.9233 for calibration set and prediction set respectively, the root mean squared error of prediction samples (RMSEP) is 0.022 and 0.072 for calibration set and prediction set respectively. Keywords: early-maturing pear, hyperspectral image, effective acidity, partial least squares (PLS).
1 Introduction Hyperspectral imaging technology is applied in research of detecting agricultural products’ quality these years; it has much potential in nondestructive inspection area. Xuehua pear’s sugar content and water content’s sensitive moisture absorption spectrum was picked up by hyperspectral imaging system, artificial neural networks *
Corresponding Author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 528–536, 2011. © IFIP International Federation for Information Processing 2011
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is used to establish Xuehua pear’s sugar content and moisture content prediction model, in this study, the feasibility of nondestructive testing of Xuehua pear’s quality in using hyperspectral imaging technology was discussed [1]. Hyperspectral imaging technology was used to predict apple’s internal quality including firmness and soluble solid [2]. Spectral bands 640-750 nm had the best effect for detecting tomatoes’ damage; this result was based on the application of partial least-square method and genetic algorithm on hyperspectral data[3]. The prediction model was obtained based on BP neural network for detecting apples’ maturity and soluble solids content from wavelength 500nm to 1000nm by using hyperspectral imaging technology [4]. As people’s life quality improved, consumer choose fruit pay more attention in internal quality such as sugar content, acidity value etc. not only in the size, color and appearance these external quality. For the quality of fruit acidity, if there is too low, the fruit will lack of flavor [5]. The acidity which people in the taste mainly depends on the acid in the state of ions, which is effective acidity, usually use pH to express and not depend on the amount of acid [6]. So, this study selects one kind of early-maturing pears—Cuiguan pear as samples to inspect effective acidity. Early-maturing pears’ hyperspectral images are collected in wavelength 400-1000nm, and partial least squares (PLS) is used to establish Early-maturing pears’ effective acidity prediction model.
2 Methods and Procedure 2.1 Fruit Samples This study selected the common early-maturing pears in south – Cuiguan pear. Cuiguan pears are wide in northern area of Jiangxi province; it has the Characteristic of early maturity, adaptability, good quality and good harvest [7]. Cuiguan pears are round in general, and mature in early August. Its flesh is white and tender, its core is small, and has a good taste. Fresh early-maturing pears are purchased from local market for this experiment, samples are randomly selected in size and shape representatively in early August 2009. Then pears had been kept in cold storage at 4 . Samples had 145 pears in all which are separated into the calibration set (77 samples) and prediction set (68 samples).
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2.2 Instrument Setup
,
,
Early-maturing pears hyperspectral imaging experiment device is shown in fig.1, this platform mainly include hyperspectral camera(ImSpector V10E Finland), light source, manual lifting device, electronic mobile platform and computer with Spectralcube software. Two 500W tungsten halogen lamps are light source.
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Fig. 1. Hyperspectral imaging platform sketch, 1. Hyperspectral camera, 2. Light source, 3. Manual lifting device, 4. Electronic mobile platform, 5. Computer
2.3 Hyperspectral Image Collections The exposure time of hyperspectral camera should be predefined before acquiring hyperspectral data to ensure the image is clear and the speed of mobile platform should be set reasonably to avoid distortion of image size and the spatial resolution. Early-maturing pear samples are took from the refrigerator and put in the tray under temperature of 24 , after the water on surface evaporated, early-maturing pears samples are in accordance with experimental environment, then the numbers could be marked on samples respectively. Standard white hyperspectral image is collected by using standard white board in the same condition with collecting samples’ images. Then the standard black hyperspectral image is collected by covering the lens. The collection of pear samples’ hyperspectral reflection images is according to the numbers marked in advance. After collecting Every 10 samples’ images, the standard white and black images should be collected again.
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2.4 Effective Acidity Measurement PH=4 standard buffer solution is used in this experiment. Using potassium hydrogen phthalate 10.21 grams dissolved in distilled water of 1000mL and set aside. The instrument for inspecting effective acidity is PHS - 3B precise digital acidometer (HongYi Instrument Co., LTD Shanghai), which is sensitive and reliable and has accurate reading. Specific operating processes are as follows: (1)
(2)
The electrode on acidometer should be connected first, and turn on the power for 30 minutes for preheating. After adjusting the temperature compensation knob, electrode are immersed in the buffer solution. Digital display of pH value on electrode is 4 (pH value of buffer solution) by adjusting potential regulator. Pulp of early-maturing pear sample is peeled, and mashed with the mortar for pear fluids.
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Electrode is washed with distilled water and dried with filter paper firstly, and washed with sample’s some fluids once more, then inserted into the sample’s fluids that is prepare to be examined. When the reading on acidometer’s display screen stable, the corresponding sample’s effective acidity is acquired.
Early-maturing pears’ effective acidity statistics are acquired through effective acidity measurement method as shown in table 1. Table 1. Statistics of effective acidity measurements of Cuiguan pear samples (pH) Mean
SD
※
Min
Max
Samples
Calibration set
5.24
0.201
4.73
5.62
97
Predication set
5.267
0.180
4.96
5.52
68
D※: Standard deviation
S
3 Spectral Image Preprocessing 3.1 Image Preprocessing In the continuous working process, the luminous intensity of light source will gradually decrease. Hyperspectral camera’s stability and repeatability will be affected because of light attenuation in the study. The images obtained would contain much noise in the band which has weak light intensity because of the uneven distribution of light intensity under the band and dark current in sensor. So image calibration is needed [8]. The standard white board is used for light calibration and standard black board is used for eliminating dark current noise in equipment etc. Sample’s original hyperspectral images turn into the absolute images after preprocessing (as shown in fig.2) in using calibrated formula.1 [9].
I norm ( x , y ) =
I sample ( x , y ) − I black ( x , y ) I white ( x , y ) − I black ( x , y )
(1) (formula.1)
In formula.1, Isample is original image, Iblack is standard black board image, Iwhite is standard white board image, Inorm is the normalized data. Effective value from 0 to 1 could be obtained by calibrating the original image. And the image calibration can reduce distraction due to such as uneven light these factors for hyperspectral image.
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a. before preprocessing
b. after preprocessing using formula 1 Fig. 2. The Vis-NIR Spectrum of sample
Fig. 3. The hyperspectral image at 723nm
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Early-maturing pear samples’ images are processed for compression by using the nearest neighbor domain method in ENVI software, and make x and y directions scale down for 0.5. Data could be reduced for this method, so image reading and data processing could be quick and could save storage space in the same time. After the image processing, early-maturing pear’s hyperspectral image is as fig.3 shown. 3.2 Region of Interest (ROI) Selection Early-maturing pear’s effective acidity measuring area is the reflecting area in filming. So visible region on early-maturing pear sample’s image is selected as interested region when process the image. The region of interest has strong brightness, which could wipe out the effect from pear’s edge and provide better data relative with early-maturing pear’s quality highly [10].Region of interest of early-maturing pear sample is selected as shown in fig.4. Early-maturing pear sample’s reflected data could be generated from this area directly after the selection of region of interest (ROI), in order to analysis and process data later.
Fig. 4. Region of Interest at 723nm
4 Results and Discussion 4.1 Spectral Range Selection Seventy-seven early-maturing pear modeling samples are tried in different wave bands many times, and different models’ effect of spectral range are discussed through partial least squares (PLS) in software of Unscrambler. Compare with the models built in other spectral range, predicted model by PLS in spectral bands 498nm – 971nm has better effect by comparison, the accuracy is highest, and comparison result is shown in table.2.
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Table 2. The model comparison in different bands RMSEC
※
No.
Correlation
R-Square
1
0.7824
0.6136
0.6248
2
0.8203
0.6728
3
0.9561
4
SEC
※
Bias
Band
0.6286
1.724e-08
399.2nm-1000.1nm
0.5749
0.5784
-5.745e-09
447.5nm-917.6nm
0.9142
0.2944
0.2961
-1.281e-06
477.9nm-993.6nm
0.9695
0.9399
0.2462
0.2477
-1.55e-06
493.1nm-980.5nm
5
0.9372
0.8783
0.3506
0.3527
-3.441e-06
600.8nm-917.6nm
6
0.9944
0.9888
0.022
0.022
-8.670e-07
498.2nm-971.5nm
7
0.9491
0.9000
0.3164
0.3183
-1.476e-06
518.6nm-971.8nm
8
0.8873
0.7874
0.4635
0.4664
-5.429e-06
652.6nm-810.5nm
9
0.9068
0.8224
0.4237
0.4262
-2.172e-05
704.8nm-810.5nm
0.9371 0.8783 0.3506 0.3527 ※ RMSEC : Root means standard error of calibration. SEC※: Standard error of calibration.
-3.441e-06
704.8nm-917.6nm
10
From the table, predicted model established by PLS in spectral band 498nm – 971nm has better effect, and has better characteristic parameter compare with the models in other bands. Therefore, the spectral band 498nm – 971nm is selected as effective band for establishing early-maturing pear’s effective acidity predicted model. 4.2 Effective Acidity’s Calibration Model The quantity of early-maturing pear samples for building effective acidity predicted model is 77. Partial least squares (PLS) in software of Unscrambler is applied in excellent spectral band from 498nm to 971nm. Through the internal cross validation, relevance between predicted effective acidity value and actual of calibration set is shown in fig.5.
Fig. 5. The calibration model of Cuiguan pear’s effective acidity
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By analyzing the figure, the predicted model of early-maturing pear’s effective acidity is built under spectral band of 498nm-971nm. The correlation coefficient R between early-maturing pear’s actual effective acidity and predicted effective acidity is 0.9944, the decisive coefficients R2 is 0.989, standard error of calibration (SEC) is 0.022 and root means standard error of calibration (RMSEC) is 0.022 in calibration set. 4.3 Model Prediction Another 68 early-maturing pears are samples in prediction set for predicting the stability of the model and the accuracy of the predicted results. The predicted results obtained from Unscrambler analysis software shown in fig.6.
Fig. 6. The prediction model of Cuiguan pear’s effective acidity
68 early-maturing pears are samples in prediction set for detecting the accuracy of model (shown in fig.6). From the figure, the correlation coefficient R between early-maturing pear’s actual effective acidity and predicted effective acidity is 0.923, the decisive coefficients R2 is 0.835, standard error of calibration (SEC) is 0.022 and root means standard error of prediction (RMSEP) is 0.072 in prediction set.
5 Conclusion Hyperspectral imaging system is used for detecting early-maturing pear’s effective acidity which is based on hyperspectral imaging technology. Early-maturing pear’s hyperspectral images are processed, the data from that are calculated by partial least squares (PLS) in the software Unscrambler for the study of detecting early-maturing pear’s effective acidity.
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The study indicates that, the wavelength from 498 nm to 971 nm is the best band to build early-maturing pear’s effective acidity prediction model. The correlation coefficient R between early-maturing pear’s actual effective acidity and predicted effective acidity is 0.9233 for prediction set; the root mean squared error of prediction samples (RMSEP) is 0.072 for prediction set. So the early-maturing pears’ effective acidity prediction model has good prediction effect and good stability. Further studies are needed to evaluate the potential of using hyperspectral technology to detect more samples for improving the model’s accuracy.
Acknowledgement This work was supported in part by the National Natural Science Foundation of China (No. 30760101), Jiangxi Provincial Department of Science and Technology (No. 2009BNB05705) and Jiangxi Provincial Department of Education (No.GGJ08513).
References [1] Hong, S., Qiao, J., Zhao, Z., Li, Z.: Nondestructive Detection of Xuehua Pear’s Quality Based on Hyperspectral Imaging Technology. Journal of Agricultural Engineering 23(2), 151–155 (2007) [2] Qin, J., Lu, R.: Measurement of the Optical Properties of Apples Using Hyperspectral Diffuse Reflectance Imaging. ASAE Paper, No. 063037. St. Joseph. ASAE, Mich. (2006) [3] Xing, J., Ngadi, M., Wang, N., Baerdemaeker, J.D.: Wavelength Selection for Surface Defects Detection on Tomatoes by Means of a Hyperspectral Imaging System. ASAE Paper, No. 063018. St. Joseph. ASAE, Mich. (2006) [4] Lu, R.: Imaging Spectroscopy for Assessing Internal Quality of Apple Fruit. ASAE Paper, No. 036012. St. Joseph. ASAE, Mich.(2003) [5] Ying, Y.-b., Liu, Y.-d.: Chinese Journal of Zhejiang University 29(2), 125 (2003) [6] Wu, X.: Food inspection technology. Chemical industry press, p. 120 (2008) [7] Du, T.: Main techniques for forest cultivation, p. 158. Jiangxi science and technology publishing company, Nanchang (2005) [8] Lu, L., Li, M., Yang, X.: A Positioning Method of Calibrating Symbols Based on High Noise Background Image. Computer and modernization (10), 30–33 (2008) [9] Liu, T.: The Detection of Residues Fruit and Surface Contaminant Based on Laser and Hyperspectral Technology, p. 6. Jiangxi agricultural university, Nanchang (2008) [10] Li, L.: The No Divided Space Color Image Retrieval Method Based on Thumbnail and EMD. Journal of Liaoning petroleum chemical industry university 29(1), 73–75 (2009) [11] Lu, W., Yuan, H., Xu, G.: Modern technology of NIR analysis, pp. 129–192. China petroleum chemical industry press, Beijing (2000) [12] Fuller, M.P., Ritter, G.L., Draper, C.S.: Partial least squares quantitative analysis of infrared spectroscopic data. Part I: Algorithm implementation 42(2), 217–227 (1988)
The Effects of Internal and External Factors on the Mechanical Behavior of the Foam Copper Longzhi Zhao1, Xiaolan Zhang1, Na Li1, Mingjuan Zhao1, and Jian Zhang2 1
School of Mechanical and Electronical Enginering, East China Jiaotong University, Nanchang, Jiangxi, P.R. China [email protected], [email protected] [email protected], [email protected] 2 School of Mechanical Electronical Engineering, Nanchang University, Nanchang 330013, China [email protected]
Abstract. The study on the mechanical properties of foam copper has become increasingly important, for the potential market in the foam metal. The Kelvin model was supposed to be the suitable model to construct the ideal open-cell, continued and three-dimensional structure. The static tensile behavior on the foam copper was simulated by ANSYS and the effects of the porosity and strain rate on the foam copper were analyzed. The results show that there is a great influence of the porosity on the elastic modulus― the higher the porosity is, the smaller the elastic modulus, and though the larger the strain rate is, the smaller the elastic modulus, the effect on it is very small. The Kelvin model exhibit a characters of anisotropy, and the displacement and the stress of the node is different form its’ location. Keywords: ANSYS, foam copper, porosity, strain rate.
1 Introduction The porous metal is a continued grid body which forms of strings or walls. The cavities is constructed by the three –dimensional polyhedron, and then called this kind of three-dimensional materials “foam materials”. The composition of the foam solid is only by the cell edges (the cavities connected by the strings) called “open-cell”, and called “closed-cell” for the walls of polyhedron is solid, and then the cavities is closed between its adjacent cavities[1]. With the rapid development of the computer technology, more and more heating of the CPU make obviously the CPU heat sink more important. For the heat sink materials is not satisfied the increasingly need of the market [2], zhang had invented a new heat sink material which called foam copper. So the mechanical properties of it are very significant and necessary. Foam copper is a new functional material with three-dimensional pore structure, high porosity which can up to 60%~95%, light specific gravity-only 10%~50% of the D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 537–542, 2011. © IFIP International Federation for Information Processing 2011
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same volume metal, high specific surface area can up to 10~40 cm2, cm3 is widely used as heat exchangers and heat sinks. With three-dimensional copper foam pore structure, higher porosity, 60% ~ 95%; proportion of light, with the volume of metal is only 10% to 50%; the larger surface area, up to 10 ~ 40cm2, cm3, can be used for heat exchangers, and heat sinks[3]. In this paper, the static tensile behavior on the foam copper was simulated by ANSYS.
2 The Establishment of the Model The Kelvin model is the ideal model that is used to simulate the mechanical properties of the lower relative density foam materials which can more truly reflect the geometric features of foam materials, which can fully fill the entire space, and can better meet the some properties. The unit cell of the Kelvin model is shown in Figure 1. What can be from the figure: it consists of 8 regular hexagons and 6 squares, contains 24 vertices and 36 pillars of equal length. Three plane-symmetry axises pass through the center of figure and four line-symmetry axises pass through the pillars of 6 squares [4]. The pillars of foam materials are conceived as same cross-section beam [5]. Kelvin multi-cell model is shown in Figure 2.Circle cross-section beam was established in this paper, and the load is imposed parallel to the direction of the extension of the cell. The Y axis is opposed to the direction, and the origin is showed at the bottom of the multi-cell model.
Fig. 1. The Kelvin model
Fig. 2. The multi-cell model
3 Discussion 3.1 The Effects of the Volume Fraction The volume fraction of the foam copper is changed by the porosity in this paper, and this means that the volume fraction is equal to the porosity in this paper. The porosity is one of the main characteristic parameters of the porous materials, which is referred to the volume of the solid compared to all of the volume. The porosity of foam is arranged
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between 85% and 95% in this paper. The mechanical properties and physical properties in the elastic area were studied in this paper. The volume fraction of the Kelvin model is shown in Eq.1.
(
)
P = 4 3π ( Ra ) − 6 + 2 ( Ra ) 2
3
(1)
Where P is porosity, R is the radius of cross section, a length of the pillar. The materials parameters are shown in Table 1. Table 1. The materials parameters
Porosity 85% 87% 89% 91% 93% 95%
Section radius /mm 0.0550 0.0515 0.0480 0.0440 0.0375 0.0315
elasticity modulus /Gpa 16.50 14.00 12.00 9.90 7.70 5.50
Poisson's ratio 0.343 0.343 0.343 0.343 0.343 0.343
shear modulus /Gpa 6.00 5.50 5.00 4.14 3.20 2.30
yield strength /Mpa 1.60 1.40 1.22 1.00 0.78 0.56
The time-displacement curves of three nodes are selected to analyze the mechanical properties of the foam copper based on the Kelvin model in this paper. The node 1156 located on the top surface, the node 3027 located on the middle of the model, and the node 11149 is closed to the bottom surface. The Y-axis time-displacement curves of three nodes are shown in the Figure 3. The results show that the increment in displacement is very small before the time of 0.1 second, the increment become large and increase linearly with the extend of the time. After stretching the model, the displacement of the node 1156 is larger than the node 3027, which is larger than the node 11149. These conclude that the more closed of the location to the force, the larger of the displacement is. This can owed to the time and space for the transmission of the force.
Fig. 3. Y-axis displacement
Fig. 4. Time-displacement curves under different porosity
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Figure 4 shows the time-displacement curves of the node 1156 under different porosity. It shows that in the elastic area, the greater the porosity, the smaller the displacement, which indirectly indicates that the greater the porosity, the elastic modulus. This manly result from that the smaller the porosity, the bigger the volume of entity, and the bigger load area, then the smaller the load of average area. The time-displacement curves of X, Y, Z axes are shown in Figure 5. What can be from the figure is that the time-displacement curves of three axes trend differently. Y, Z axes exhibit increasing trend, while X axis exhibit opposite. The increment of the Z axis is small than Y axis, for the Y axis is the direction of the force. So the Kelvin model has anisotropy character. This is accord with the LU’s statement.
Fig. 5. Time-displacement curves of X, Y, Z-axes of the node 1156
Fig. 6. Time-displacement curves of X, Y, Z-axes of the node 3027
3.2 The Effects of the Strain Rate The porosity of the foam copper is set as 85%, and the model is the same to above. The effect of the strain rate on the elastic modulus is shown in Figure 7. It can be seen from the figure that the elastic modulus doesn’t exhibit linearly increase with the strain rate. The larger the strain rate, the smaller increment of the elastic modulus. The elastic modulus decrease, but it decreases small. Then can conclude that the effect of the strain rate on the elastic modulus is very small. It may be appearing a situation, the elastic modulus may be stable when the strain rate up to a limit. This is equal to the elastic modulus has a limit. This because that the strain rate would not neither change the internal structure and properties like the porosity and the aperture nor alter the external circumstance in order to change the internal properties like the temperature. The Y-axis strain rate-displacement curves of three nodes located differently are shown in Figure 8. It shows apparently that the curves of the node 1156, 3027, and 11149 don’t intersect, and different greatly. Especially in the situation of the small effect of the strain rate on the elastic modulus, the increment of the node’s displacement depend on the location very largely. This indicates that the node distance from the force affect directly the stress and the displacement. This is because that though in static model, the more far to the load, the longer the time of the transmission, for the time and the space is necessary for the transmission of the load. And in the process of
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transmission, it is inevitable for the loss of the force. Then the displacement and stress is small with distant location. The Equivalent stress nephograms of the different location of the node are shown in Figure 9. The stress is increased gradual from blue to red. The same conclusion can be from the figure. What can be seen from the figure is that the stress is the biggest in the intersection. Although the angles between the pillars are not right angle, it is not beneficial to transfer the force especially in the intersection which is easy to concentrate the stress.
Fig. 7. Elastic modulus-strain rate curve
Fig. 8. Displacement-strain rate curves of different location
Fig. 9. Equivalent stress nephograms of the different location
4 Conclusion (1) The elastic modulus varies largely under different porosity. The elastic is high increase with the decreases of the porosity. (2) The elastic modulus decrease with the strain rate increasing, but the range is very small. (3) The stress and displacement largely depend on the location from the load, and the stress and displacement is larger with closed distance. (4) The Kelvin model exhibits anisotropy character.
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References 1. Zhang, J.Y., Zhang, P., Gan, Q.L., Xiao, Y.X.: The Properties of Representative Units of Porous Materials. J. Engineering Mechanics 21(2), 124–129 (2004) 2. Hao, Y.G., Liu, L.: Thermal design of electronic equipment. J. Ordnance Industry Automation 29(2), 49–54 (2010) 3. Cao, G.Y., Wang, F., Wang, L.C.: The Mechanical Property and Progress of Metal Foams. J. Research Studies on Foundry Equipment 2, 51–54 (2008) 4. Shi, S.L., Lu, Z.X.: Finite Element Analysis for The Elastic Modulus of Open-cell Foams Based on a Tetrakaidecahedron Model. J. Journal of Mechanical Strength. Henan. 28, 108–112 (2006) 5. Xie, L.S., Chen, M.H., Tong, G.Q., Gao, L.: Anisotropic Elastic Properties of Foam Metal with Open Cells. J. Materials for Mechanical Engineering 27, 7–16 (2003) 6. Lu, Z.X., Huang, J.X., Chen, X.: Elastic Properties of Anisotropic Kelvin Model for Open-cell Oams. J. Acta Aeronautica Et Astronautica Sinaca 6, 1017–1022 (2009)
Optimum Design of Runner System for Router Cover Based on Mold Flow Analysis Technology Tangqing Kuang and Wenjuan Gu School of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang 330013, China [email protected]
Abstract. During the design of a two-cavity injection mould for router covers, two plans, single-gate plan and dual-gates plan, were setup based on the results of best gate location analysis combined with other aspects. Then fill analysis for the two plans were carried out. The dual-gates plan was selected as an optimal choice for its smaller clamping force, wall shear stress and injection pressure in comparison with the single-gate plan. Although weld lines and air trap exists between the two gates, but they can be eliminated or just have a little effect on the quality of parts. It indicated that the technology of mold flow analysis can be used to optimize the design of gate location and gates number and assist the engineers to improve the quality of their designs of mould. Keywords: Mold flow analysis, Gate location, optimum design.
1 Introduction The use of plastic has been spread to all walks of life, about 80% plastic production used injection molding method. Therefore, improving the design quality is the key to improve the products quality, productivity and reduce production cost. For a given part design, the runner system design is one of the key issues of its mold design. The complexity of mold structure and cost of mold are determined by the form of gating system directly [1]. Section size and length of the runner system affect the pressure loss of melt flow directly [2,3]. Gates location and its number affect the flow behavior of melt in the cavity and eventually affect the quality of product [4]. Using traditional methods which rely on the experience to design gating system can not gain a better runner system, and if we encounter a complex part or not covered before, the gate design can not success in once, we often have to go through a trial mode-modify-try mode-and the modify the phase, that is a great waste for time and cost. With the CAE technology for injection molding developing, mold flow analysis has been successfully used in injection mold design process [5]. By means of mold flow analysis, the optimized gating system becomes a reality. By the flow analysis for different proposals of gating system and comparison of the analysis results such as filling status, weld line location, air trap location, injection pressure, clamping force and other results, the optimal proposal achieved. That can aid the engineers to optimize their design. Take a router cover for an example, the procedure of optimization runner system of injection mold by mold flow analysis techniques was illuminated in this paper. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 543–554, 2011. © IFIP International Federation for Information Processing 2011
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2 Modeling and Meshing The router cove is 430 mm long, 81 mm wide and 28 mm height and shown in Figure 1. And the model was output in iges surface format for the convenient of meshing in Moldflow Plastic Insight (see Ref. 1), software of mold flow analysis for injection molding.
Fig. 1. Router cover model
Fig. 2. Meshed router cover model
The iges model was imported into MPI and meshed in fusion type with 3785 elements and 1869 nodes, which shown in figure 2.
3 Gate Location Analysis and Programming Gate location analysis was conducted for the model and the result shown in Figure 3. The blue area shows the suggested best gate location for the cover. The gate location analysis does not take into account some practical considerations for the gate location such as the type of tool, or limitations on the gate location due to part aesthetics etc. The router cover is limited to a 2-plate tool with a cold runner system. As a result of that tooling restriction, the suggested best gate location for the cover, in the middle of the part, is not possible. These results can only be used as a guide to place a gate on the parting line.
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Fig. 3. Best gate location result
For a long kind of part, two-cavity mold layout is a rather good choice. Considering parting location of the router cover, cavity layout of the mold, appearance requirements of the product, simplification and reliability of the mold structure and the best gate location result, single side gate was adopted and it locates at the middle of the part in length direction, close to the best gate location result. Considering the larger size of the part in length direction, another plan which dual side gates locate at the sides of the best gate location result is proposed. Single-gate and dual-gates runner system are shown in Figure 4 and 5 respectively.
Fig. 4. Single-gate plan
Fig. 5. Dual-gates plan
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4 Comparison and Analysis of Plans 4.1 Process Parameters Setting ABS material was used to meet the requirement of strength and hardness of the part. Lanxess ABS 1146 of Lanxess Corporation is selected here. For comparison, the two programs are used same process parameters, mold temperature 80 , material
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(b) Fig. 6. Fill time of single-gate plan (a) and dual-gates plan (b)
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temperature 260 , flow rate 200cm3/s; speed / pressure switch is set to 100% of the filling volume. The better program is chosen by comparing the analysis results of the two programs such as filling time, the pressure distribution at the end of filling time, the distributions of weld line and air trap, the maximum injection pressure and clamping force, the maximum wall shear stress and so on. 4.2 Comparison of the Analysis Results of the Two Programs The fill time result shows the progression of the flow front. Figure 6 (a) and (b) show the fill time results of single-gate plan and dual-gates plan respectively. They indicate that the filling time of the two plans are all about 1.45s and they all filling completely. The flow fronts meet at 0.59s in dual gates plan. Pressure at the end of fill will affect the residual stress in the molding parts, the greater the pressure, the greater the residual stress. If the pressure is uneven, the larger the difference, the more uneven the residual stress, the larger the warpage consequently. So the pressure at the end of fill needs to be uniform as far as possible. Pressure distribution at the end of filling time of single-gate plan and dual-gates plan are shown in figure 7 (a) and (b) respectively. The pressure difference is about 85MPa in single-gate plan while it’s 63MPa in dual-gates plan. Pressure distribution in dualgates plan is more uniform than that in single-gate plan.
(a) Fig. 7. Pressure distribution at the end of filling time of single-gate plan (a) and dual-gates plan (b)
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(b) Fig. 7. (continued)
Weld lines occur where two or more flow fronts converge. The presence of weld lines may indicate a structural weakness and/or a surface blemish. Weld line strength is influenced by the temperature at which the weld line is formed and the pressure exerted on the weld while the material is within its recommended processing temperature range. Weld line results with the flow front temperature highlightened of singlegate plan and dual-gates plan are shown in figure 8 (a) and (b) respectively. In the two plans, weld lines exist near the rectangular hole and small radial holes. But all the flow front temperature at weld lines are about 260 which is melt injected temperature. In comparison with single gate plan, an extra long weld line exists between the two gates in dual-gates plan, but the flow front temperature and the pressure exerted on them are high, so the weld line strength is ensured and it has less negative impact on part quality. Air trap occurs at the ends of flow paths or where the melt stops at a convergence of at least two flow fronts. The presence of weld lines may indicate a structural weakness and/or a surface blemish and should be avoid by taking some measures. Figure 9 (a) and (b) show the air trap distribution of single-gate plan and dual-gates plan respectively. In comparison with single gate plan, extra air traps exist between the two gates in dual-gates plan. The air trap existing where the melt stops at a convergence of several flow fronts can be eliminated by setting knockout pins or adopting the mosaic of core there. And the air trap existing at the ends of flow paths can be eliminated by the venting at the parting plane.
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(b) Fig. 8. Weld line distribution of single-gate plan (a) and dual-gates plan (b)
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(b) Fig. 9. Air trap distribution of single-gate plan (a) and dual-gates plan (b)
The selected injection molding machine must meet the requirements of the maximum injection pressure and clamping force. The higher the maximum injection pressure and clamping force are, the more the energy consumption is and the higher the injection molding machine specifications is. Pressure trace at the injection location of single-gate plan and dual-gates plan are shown in figure 10 (a) and (b) respectively. The maximum injection pressure in single-gate plan is 114MPa while it’s 106 MPa in
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dual-gates plan. Figure 11 (a) and (b) show the clamp force development of singlegate plan and dual-gates plan respectively. The maximum clamp fore in single-gate plan is 344 ton while it’s 259 ton in dual-gates plan.
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(b) Fig. 10. Pressure trace at the injection location of single-gate plan (a) and dual-gates plan (b)
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(b) Fig. 11. Clamp force of single-gate plan (a) and dual-gates plan (b)
Shear flow is the main flow behavior during the filling stage of injection molding and the maximum shear stress exist near the wall. The wall shear stress needs to be below the maximum allowable shear stress of the used material as far as possible to avoid material degradation for the excessive shear stress. The maximum allowable shear stress of selected material is 0.25MPa. The analysis log result shows that the maximum shear stress and average shear stress in single-gate plan are 0.922 MPa and 0.185 MPa respectively. The maximum
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shear stress and average shear stress in dual-gates plan are 0.816MPa and 0.173MPa respectively and they all less than the values of single-gate plan. Shear stress at wall of single-gate plan and dual-gates plan are shown in figure 12 (a) and (b). As we can see, most of the shear stress at wall of dual-gates plan are below the allowable shear stress 0.25 MPa while shear stress at wall at a large area of single-gate plan exceeds the allowable value.
(a)
(b) Fig. 12. Shear stress at wall of single-gate plan (a) and dual-gates plan (b)
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4.3 Choice In comparison with the single-gate plan, the dual-gates plan has smaller clamping force, wall shear stress and injection pressure. Although weld lines and air trap exists between the two gates, but they can be eliminated or just have a little effect on the quality of parts. So the dual-gates plan is selected as an optimal choice.
5 Conclusion In this paper, comparison and selection of different gate settings is conducted by mold flow analysis. Finally we get the best gate location and gate panel number for the router which is the author’s major work, The length and cross section size can be determined by the following choice of mold plate and the mold specifically designs. The runner section size can be optimized by runner balance analysis. And the gate section size can be optimized to ensure the full compensation by packing analysis and cooling analysis. The resulting optimum runner system can be used to improve product quality. From this example, we know that the successful application of mold flow analysis for injection mold design provides the scientific basis and reference for mold designers and aids designers to optimize the design programs, reduce testing time, and improve qualities of mold and products.
Acknowledgments This work forms part of a project supported by the Education Department of Jiangxi Province with grant GJJ10126.
References 1. Beaumont, J.P.: Runner and Gating Design Handbook: Tools for Successful Injection Molding. Hanser Gardner Publications (2004) 2. Lee, K.S., Lin, J.C.: Design of the runner and gating system parameters for a multi-cavity injection mould using FEM and neural network. The International Journal of Advanced Manufacturing Technology, Published by Elsevier Science Ltd, (2006) 3. Zhai, M., Lam, Y.C., Au, C.K.: Runner sizing and weld line positioning for plastics injection moulding with multiple gates. In: Engineering with Computers. Springer Publishing, Heidelberg (2006) 4. Lee, J., Lee, J.: Gate positioning design of injection mould using bi-objective micro genetic algorithm. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, Professional Engineering Publishing (2008) 5. Moldflow Corporation: Simulation Fundamentals-An Introduction for MPI 6.0. Moldflow Corporation, Boston, America (2006)
Design of Tread Flange Injection Mold Based on Pro/E Huilan Zhou Key Laboratory of Ministry of Education for Conveyance and Equipment, East China Jiaotong University, Nanchang, Jiangxi 330013 [email protected]
Abstract. In the paper, analyzing the tread flange structure characteristics, its injection mold is designed and the maneuvering tread demolding way is applied to get out flang tread .When designing demolding parts, hydraulic pressure motor and chain-gear mechanism are used. Besides, parting plane and the forming parts can be gained automatically in Pro/E(Pro/Engineer Wildfire3.0 and standard moldbase can be achieved by EMX4.1 including gating ,cooling, and guiding system, etc. The designing ways and structure is proved rational and can be taken as reference for the similar injection mold especially for those with longer tread.
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Keywords: tread flange, maneuvering tread demolding way, Pro/E; EMX4.1.
1 Introduction For plastic parts, many have thread with them, and it’s most critical how to design its automatric tread demolding as the tread demolding structure will effect the mold life and the plastic part quality directly . How to simplify the mold and prolong its life needs to be considered in designing. Besides, with wide application, rapid updating and high quality of plastic parts, digital designing ways such as CAD tools are used in the mold designing and manufacturing in many fields. Among those tools, Pro/E and UG are used most widely. These two softwares have become standard ones in the mold industry of many countries. In the paper, the tread flange injection mold design based on Pro/E is introduced.
2 Tread Flange Structure and Process Analysis The tread flange’s size is 60mm ×70mm×20mm with 12mm external tread, and it has five pleurotus around which can prevent part from rotating in tread demolding shown in Fig.1. Tread flange’s material is PP(Polypropylene)[1-3] with mass production. PP is a kind of material with following character: density 0.90 ~ 0.91g/cm3, melting point 164 ~ 170 . PP also has good heat resistance, fine flow performance, less shrinkage and smooth surface.
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(a) plastic part diagram
(b) 3D diagram
Fig. 1. Tread flange
3 The Mold Parting Plane Design The mold parting plane is generally utilized to separate workpiece or block into mold forming parts, which is composed of a surface or several surfaces. It’s important to create correct parting plane and use it to obtain mold forming parts such as cavity, core and pins in mold designing in Pro/E. For tread flange, after using Pro/E to create its parting plane and separating workpiece with it, the tread flange mold forming parts can be achieved following in Fig.2.
(a) fixed plate
(b) mobile plate
(c) mold core
(d) mold cavity
Fig. 2. The mold forming parts
4 The Injection Mold Design 4.1 The Mold Overall Structure The mold overall structure is shown in Fig.3. As the tread flange has greater total length and longer external tread, some difficulty will confront in its designing and manufacturing , among which separating mechanism according to distance and auto tread demolding must be resolved in designing.
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(a) main view
(b) left view 1- movable base plate 2- Screw3-supporting plate 4-chain5- Sprocket I6- hydraulic Motor7-pin8Screw2 9- Guide column10- guide sleeve11- fixed base plate 12- Determined distance pole13Screw314fixing plate15- Spring16-closing mold tool17-resisting plate18-seperating watar plate19-up mold core 20-water mouth21-fixed plate22-fixed mold plate 23-movable plate 24 screw core25-gear26-movable mold plate 27- Sleeve 28-bearing 29-bearing cover 30-seals31-Seal adhesive32- Sleeve2 33-Sprocket 34-Key 35-briquetting 36-screw4 37- Guide column38- guide sleeve 39-Gate sets 40-pulling pole41-screw4 Fig. 3. Overall structure of the mold
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4.2 Injection Machine Selection With calculating tools in Pro/E , the tread flange’s total volume including gating system and the plastic part itself can be calculated as 111.822 cm3.Apart from that, considering clamping force and opening stroke, the injecting machine G54-S200/400 is selected, whose Specifications is following:
㎝: ㎜: : ㎜: : ㎝: ㎜: ㎜: ㎜: ㎜: ㎜:
Rated injection volume/ 3 200-400 Screw diameter/ 55 Injection pressure/MPA 109 Injection stroke/ 160 Clamping force /KN 2540 Maximum molding area/ 2 645 Maximum die plate stroke/ 260 Maximum die thickness 406 Minimality die thickness/ 165 Sprue circle radius/ 18 Sprue diameter/ 4 4.3 The Maneuvering Tread Demolding Structure Design There are three common methods for tread demolding: manual tread demolding, forcing tread demolding and auto tread demolding. For those plastic parts of high quality with mass production, auto tread demolding ways which include maneuvering demolding, half- sliding demolding and combined mold demolding can be applied. In the tread frange mold, maneuvering tread demolding is selected. The maneuvering tread demolding has the advantage of high efficiency and steady, and in designing, its feasibility, stability and wearing property must be considered seriously and resolved successfully. AS the tread flange has greater total length and longer external tread, when maneuvering tread demolding, if the traditional rack and pinion is applied, problems must occur in designing and manufacturing as its opening distance is too long. So in the mold, hydraulic pressure motor and chain-gear mechanism are selected in demolding agency. Compared with electric motor, hydraulic pressure motor is more steady, lower noise, and stepless speed regulation. And compared with belt drive, chain drive has nonslipping with good transmitting ratio, small tension, and small load played on axis. Now hydraulic pressure motor and chain-gear mechanism have become a more popularizd thread demolding agency. 4.3.1 The Transmission Mechanism [4] Design The main chain-gear transmission diagram in the mold is in Fig.4.
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z1:tooth number of driving gear z3:tooth number of driving sprocket
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z2:tooth number of drived gear z4: tooth number of drivied sprocket
Fig. 4. Chain-gear transmission diagram
(1) The gear parameter design In the moldbase of tread flange, the center distance between two gearing shafts is 120mm, and the main gear parameters are following: Diametrical pitch/mm: 2.5 Tooth number: z1=28 z2=20 Pitch circle diameter/mm: D1=70, D2=50 Gear width/mm: B1 20, B2=30 (2) Bearing selection Axis with parts on it is located by bearing and bearing cover in axial and radial directions for the stability. According to the force loaded on the axis ,the deep groove ball bearing 61805 is selected in the design. 3 Chain transmission parameter According to reference [5], the plastic part enveloping force can be calculated as following: F=28.1KN. Considering the enveloping force on the core coming from the plastic part, the chain 16B in GB/T 1243-1997 is selected whose tensile load is 60KN and pitch 25.4mm with single row and short pitch. The parameters of the Sprocket in the mold is designed as: z3=54 ,z4=20. 4 The transmission ration calculation As the total thread’s length is 12mm, and thread pitch is 1.5mm, so the thread number can be calculated as 8. The formular of overall ratio is next:
, =
()
()
i=(z2/z1)(z4/z3)≈0.26
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In the formula, the meanings of z1,z2,z3 and z4 are shown in Fig.4.It can be illustrated from the formula 1 that in order to pull the thread out of the core thoroughly the gear must be drived by the hydraulic pressure motor to work at least 32 rounds.
()
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4.3.2 Hydraulic Pressure Motor Selection Considering the plastic part previous enveloping force , and after composite calculating, the hydraulic pressure motor Nmh1-163 is selected ,whose Specifications are next: Rating torque/ n.m: 225 Wept volume/ ml/r: 64 rated pressure/ mpa :25 rated torque/ n.m: 472 speed range/ r/min: 15-1500 weight/ kg: 20 Besides, in order to protect the thread from being breaked, it is better to run the hydraulic pressure motor slowly. 4.4 Separating Mechanism According to Distance and Mold Working Process Three plates mod is adopted shown in Fig.3, in which the hydraulic pressure motor and chain-gear mechanism are used to realize auto thread demolding. The mold primary working process is as following: at first, after mold being closed and cavity being filled fully, the parting plane I opens and the pin point gate separates from the plastic part under the action of spring 15 ; secondly, with the help of the die locker 16, the parting plane II can be ensured to be opened before the parting plane III, as a result cooling slag of the runner can be get out; finally, under the action of separating mechanism, movable mold can be separated totally from fixed one and then the cooled plastic part will be removed from core in movable side by motor-chain-gear mechanism.
5 The Moldbase Design Most of injection moldbase have already been standardized. From standardized moldbase loading, sliding-block creating to casting system designing, and from ejecting mechanism to cooling system, all of them could be achieved in standardized moldbase. EMX(Expert Moldbase Extension)4.1 is such a tool ,which is a plug-in belongs to Pro/E and can be used to design standard moldbase parts such as mold plate, sliding block, pin and cooling system and so on. Besides, emulation of mold opening and interference checking can also be realized in EMX 4.1[6,7]. The moldbase main designing steps in EMX4.1 are as following: (1) Assemble the forming parts such as mold core, cavity and sliding block into the moldbase so that EMX4.1 can identify them; (2) Definite mold subassembly including moldbase type selection, the mold plate dimension, mold layout, locating ring and sprue bush; (3) Design the gating system. The sprue runner, sub-runner and gate can be quickly achieved in EMX4.1 using standard runner tool; (4) Design sliding block mechanism including outside core-pulling and inner side core-drawing mechanism;
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(5) Design ejector mechanism. As the hydraulic pressure motor and chain-gear mechanism are used to realize auto thread demolding, ejector mechanism needn’t be designed in the tread frange mold; (6) Design cooling system. After cooling waterline has been drawn in the cooled parts, cooling system can be gained automatically using EMX’s gating tool. (7) Assemble moldbase. Assemble all the parts achieved previously to the moldbase, shown in Fig.5.
(a) overall moldbase
(b) moldbase without fixed mold Fig. 5. Moldbase
6 Conclusions (1) In the mold, the hydraulic pressure motor and chain-gear mechanism are applied to realize maneuvering thread demolding successfully. Compared with other mechanism, this kind of mechanism can work accurately and stable for demolding, with low noise, good quality and high efficiency. (2) The CAD technology has been used in the mold and moldbase design by means of Pro/E and EMX4.1, thus the cycle of developing a new part can be shorten rapidly and the mold costs in designing and manufacturing can be reduced greatly. The maneuvering thread demolding way and CAD technology in the mold designing can be considered as a successful example for other similar mold with tread structure.
References 1. Hong, S.-Z.: Practical Mold Design and Injection. Machinery Industry Press, Beijing (2006) 2. Qu, H.-C.: Injection Mold Design and Molding Process. Higher Education Press, Beijing (2001) 3. The writers of Manual Of Injection Mold: Manual of Injection Mold. Machinery Industry Press, Beijing (2000) 4. Hong, J.-D., Li, M., Huang, X.-Y.: Guide of Mechanical Design. Nanchang University Press, Jiangxi (2001)
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5. Dang, G.-M., Luo, Z.-B., Li, J.-R.: Mold Design and Manufacture. Xidian University Press, Xian (1995) 6. Xiao, Q., Zhou, H.-L.: Practical teaching of Mold Design and Manufacture in Chinese With Pro/Engineer Wildfire3.0. China Electric Power Press, Beijing (2008) 7. Hua, J.-h.: Quick Design of Injection Moldbased on Pro/E. Die & Mould Manufacture, 12–15 (2006)
Study on the Online Control System to Prevent Drunk Driving Based on Photoelectric Detection Technology Lu Liming1, Yang Yuchuan2, and Lu Jinfu1 1
East China jiaotong university, Nanchang, 330013, P.R. China [email protected]
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Yichun Vocational Technical College, Yichun, 336000, P.R. China
Abstract. A drink driving online control system based on photoelectric detection technology is introduced in the paper. The system can take the initiative to force motor vehicle drivers to test their drinking status, and reasonably control the driver’s behavior accordingly. The basic principle is to use the characteristic that 1185nm wavelength IR is absorbed by alcohol the most easily to detect the motor vehicle driver's alcohol concentration and to determine the extent of motor vehicle drivers drinking. The alcohol concentration detected is converted into photoelectric signal that is handled by 89C2051 MCU. The signal handled is exported to voice devices to get voice prompts and warning, and exported to the relay of ignition circuit system to cut off the ignition system to control the engine's starting and prevent the driver drunk driving, and exported to electro-hydraulic proportional flow valve to control the maximum speed of motor vehicle according to the driver’s alcohol content. The purpose of this study is to be able to effectively solve the problem of drink driving and avoid serious traffic accidents resulting from drunken driving. Keywords: Photoelectric Technology, Drunk Driving, Control System.
1 Introduction The danger of drink driving motor vehicle is known as we all. "Drivers shall not drive a motor vehicle after drinking" is clearly stated in Article 2 of "The People's Republic of China Road Traffic Safety Law.", but some motor vehicle drivers have luck idea in their brain, resulting in the provisions existing in name only, causing a number of serious accidents. To avoid this incident happening, a drink driving online control system based on photoelectric detection technology is introduced in the paper.
2 The Overall Program of Realizing the Online Detection Control System to Prevent Drunk Driving By a gas absorption device constituted by an airflow sensor and a temperature sensor, motor vehicle drivers are forced to detect their breath alcohol concentration before driving, to prevent them to avoid alcohol testing by ventilating through the windows and covering the test probes and other means. The test of alcohol concentration of D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 563–567, 2011. © IFIP International Federation for Information Processing 2011
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motor vehicle drivers is done by the equipment detecting breath alcohol concentration based on IR spectroscopy. The optical signal obtained by the test is turned into electric signal by photoelectric detector and magnified by amplifier. The output signal of the alcohol concentration testing device and the output signal of the gas absorption device are respectively inputted control circuit device and processed by the 89C2051 MCU. The new signal got is exported to voice devices to get voice prompts and warning messages, exported to the ignition circuit of the start system to control the motor vehicle start, exported to electro-hydraulic proportional flow valve to limit vehicle maximum speed. The specific procedure is shown in figure 1.
Fig. 1. The online detection and control system to prevent drunk driving
3 The Gas Absorption Device to Force Motor Vehicle Drivers to Detect Their Breath Alcohol Concentration Before Driving The gas absorption device accepting the motor vehicle driver’s breath gas mainly consists of a temperature sensor and an airflow sensor, to control the relay turning on and off the ignition system. The purpose of using the temperature sensor is to Identify whether the air is human body’s gas. The basic principle of the temperature sensor generating electrical signal is to compare gas flow temperature and ambient temperature, because the gas temperature of human body breathing is higher than ambient temperature, to determine whether the electrical signal is generated. The purpose of using the airflow sensors also is to Identify whether the air is human body’s gas. The basic principle of the airflow sensor generating electrical signal is to compare the gas flow rate of human body breathing and the flow rate of the environment air to determine whether the electrical signal is generated, because the gas flow of human body breath is faster than the gas flow of environment air in cab. When the two sensors generate signals at the same time, the motor vehicle driver’s breath can be regarded as being valid to prevent the driver to avoid detection.
4 The Alcohol Concentration Detector Based on Spectroscopy Technology It was found by experiment that the most IR wavelength absorbed by alcohol is 1185nm[1], and the most IR wavelength absorbed by carbon dioxide is 1575nm , and the most IR wavelength absorbed by water vapor is 1315nm . Under normal
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circumstances the gas of human body exhale mainly contains of carbon dioxide and water vapor. The extent of motor vehicle drivers drinking can be determined by observing the absorbed situation of wavelength
1185nm[1] IR when it passes through
the gas region of the driver exhale. Testing device is shown in Figure 2. Using hollow cathode lamp to generate wavelength 1185nm IR, when it passes through the gas region of drivers exhale, alcohol will absorb some of its spectral energy. Using wavelength selector further to filter out other wavelengths of the spectral, the remaining spectral energy is converted into electrical signals by the optical converter. The electrical signal is amplified by the amplifier and then is sent to the control circuit device.
Fig. 2. Alcohol concentration detector
5 Drunk Driving Control Circuit System The voltage of control circuit is +5V. The control system mainly consists of 89C2051 MCU[2], MTP337A temperature sensors, speed sensor, gas flow sensor, voice prompt module, voice warning module, on-off relay, electro-hydraulic proportional flow valve etc. The core is 89C2051 MCU. Their mutual relation is shown in Figure 3. If the alcohol content exceeded the standard, the alarm
Fig. 3. Drunk driving control circuit system
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module will issue a voice warning and the on-off relay control module will cut off the vehicle's ignition circuit so that the driver can not start the car. If the alcohol content was not exceeded the standard, the voice prompt module will prompt the driver to slow and the electro-hydraulic proportional flow valve will Limit vehicle maximum speed.
6 Drunk Driving Speed Control System The optical signal produced by the alcohol concentration detector is enlarged, then is processed by 89C2051 MCU, is compared with pre-set the alcohol maximum concentration signal. Final the vehicle is controlled accordingly. If the driver's alcohol concentration measured was higher than the pre-set the alcohol maximum concentration, the 89C2051 MCU will output signal, and supply power to the relay of ignition circuit system. The relay will cut off the ignition system to the engine not be start. If the driver's alcohol concentration measured was less than pre-set the alcohol maximum concentration and speed measured by speed sensor reached up to the speed needing to control under the alcohol concentration, the 89C2051 MCU will export signal to the drunk driving speed control system so that the vehicle speed can be controlled within the speed that the driver can safely travel under the alcohol concentration. The drunk driving speed control system mainly consists of accelerator pedal, Spring, hydraulic cylinder, hydraulic control valve, check valve, relief valve, oil tank and some tubing etc. The relationship between the various components is shown in Figure.
Fig. 4. Drunk driving speed control system
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Hydraulic cylinder is a special cylinder. It has some holes in different locations and is connected with the hydraulic control valve by some tubing. Hydraulic control valve is an electro-hydraulic proportional valve. At different currents, the spool of hydraulic control valve can move different distances to seal different the holes. Spring has the role to reset the automobile accelerator pedal. Check valve has a complementary role to oil. Relief valve has a role to set oil pressure. The control principle of the drunk driving speed control system is that 89C2051 MCU exports corresponding signal to the electro-hydraulic proportional flow valve according to the driver's the alcohol concentration measured, so that its the spool can produce different mobile to seal different holes which connect with hydraulic cylinder, to control the piston of hydraulic cylinder to move different distances, to control the opening size of the vehicle throttle. The size can control vehicle speed.
7 Summary Above the study shows that the online control system to prevent drunk driving can take the initiative to force motor vehicle drivers to test their drinking status, and reasonably control the driver's driving behavior accordingly. The basic principle is to use the characteristic that 1185nm wavelength IR is absorbed by alcohol the most easily to detect the motor vehicle driver's alcohol concentration and to determine the extent of motor vehicle drivers drinking. The alcohol concentration detected is converted into photoelectric signal that is handled by 89C2051 MCU. The signal handled is exported to voice devices to get voice prompts and warning, and exported to the relay of ignition circuit system to cut off the ignition system to control the engine's starting and prevent the driver drunk driving, and exported to electro-hydraulic proportional flow valve to control the maximum speed of motor vehicle according to the driver’s alcohol level. The study shows the system can effectively solve the problem to prevent drunk driving and avoid serious traffic accidents due to drunk.
Acknowledgements The research was supported by the National Natural Science Foundation of China “The Study of the Principle and tribological design basis of the roll and slide blend bearing in circle pound situation. ”(Grant No.51065009).
References [1] Feng, J., Zhou, Y., Liu, G., Wu, T.: The optical characteristics of alcohol and alcoholicity detection. Chinese Journal of Spectroscopy Laboratory (March 2006) [2] Li, Z., Xu, Z., Wang, J.: Active breath alcohol detector. Journal of North China Institute of Aerospace Engineering (October 2009)
The Design and Simulation of Electro-Hydraulic Velocity Control System Fengtao Lin* Key Laboratory of Ministry of Education for Conveyance and Equipment, East China Jiaotong University, Nanchang 330013, China [email protected]
Abstract. In this paper, the principle of electro-hydraulic proportional control system are introduced, electro-hydraulic velocity control system are designed and can realize volevity control with high accuracy. In the system, relative amplitude abundant degree and phasic abundant degree and corresponding frequency of passing of Body system is easily obtained under different open ring gain of K, thus it is simple and accurate to choose reasonable parameters, and then can carry on smulation to system by Matlab/Simulink to examine the design results. Keywords: Electro-hydraulic servo system, Matlab, Simulation.
1 Introduction Velocity control system[1,2]is widely used in practical projects need for velocity control, such as turrets, radar, turntable, etc; and the projects need for straight line motion velocity control, such as lifting platform, mail-sorting machine automatically conveyor, machine tool feeding device, etc. velocity control system with electro-hydraulic servo controller is a control circuit that output velocity variation feeds back to the input side via the sensor. In electro-hydraulic velocity control system[3,4] designing, the traditional approach is to identify the system composition and control mode based on the requirements, then to build the mathematical model and the system parameters, and adjust the open loop gain K of the system to ensure the system stability based on the bode diagram or nyquist diagram analysis of the open loop transfer function. In this paper, open-loop transfer function of a system was described use matlab language, the amplitude margin, phase margin, and the corresponding crossover frequency of the relatively stable system can be calculated after evaluating the K value. According to the critical condition of the system stability margin, the K value is adjusted and the new gain margin and phase margin were calculated repeatedly until at least one of the margins close to the critical condition steadily at the premise of all stability conditions are meet. and the parameters k value was decided. In this way, the open loop system amplitude and crossover frequency increased as much as possible, and also ensure the system stability. A rotating device velocity control system design of an equipment was presented as an example to illustrate the application of this method. *
Corresponding author. Tel.: 13970842969.
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2 Methods and Applications A device rotator system parameters are defined as follows[5]: Load rotational inertia
~
J = 0.4 kg·m, rotational velocity range n =35 200 r/min, Working Pressure p =8MPa, Maximum load torque M =50N·m, static gain of velocity Sensor is 20V /1000 r ⋅ min −1 , and performance index requirements are defined as follows: tracking precision is ±1 r /min, completing the tracking task accurately within 0.15 s. 2.1 Working Principle of the Contronl System As the control power is smaller, so valve- controlled electro-hydraulic system[6] is dominated directly by the servo valve. The working principle is shown by Fig. 1.
ui
+
×
ue
I
QL
− uf
θm
θm
Fig. 1. Diagram of system working principle
Where,
ui is velocity contronl singal; ue is deviations; I is input current; QL is servo
valve flow; θ m is output velocity; u f is feedback. '
2.2 Motor Discharge In this paper, maximum load value is two-thirds of supply oil pressure value and is found to be: PL =
2 2 P = × 8 ×106 = 5.3MPa 3 3
motor discharge is found to be: Dm =
(1)
2π M 50 = = 9.434 ×10 −6 m3 /rad 2π PL 5.3 × 106
The BM1210 type cycloid hydraulic motor was selected, and the discharge Dm is: 163 ×10−7 m3 /rad .
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2.3 Servo Valve Specifications Determination The servo valve flow is found to be: −3 3 QL = 2π Dm nmax = 2π ×163 ×10 −7 × 200 = 20.4 ×10 m /min ,
pressure drop is:
pV = p − p L = 80 × 105 − 53 × 105 = 27 × 105 Pa QDYI2C63 type servo valve can meet the parameters requirements, and it’s rated no-load flows QV is 1.05 ×10−3 m3 /s ,rated current IV is 0.03A, supply oil pressure is 137 ×105 Pa. 2.4 The Dynamic Characteristic Determination Control system diagram is shown as figure 2,where, K a is integral amplifier gain,
KV is servo valve gain, ξV is damping ratio of the servo vaulve, ωV is natural frequency of servo valva; Dm is the hydraulic motor displacement, ωh is natural frequency of hydraulic motor,
×
ui +
−
ue
ξh
Ka S
uf
is the damping ratio of hydraulic motor.
I
s2
ωV 2
+
KV 2ξV
ωV
QL s +1
s2
ωh 2
KT
1 Dm 2ξ + V s +1
θm
ωh
θm
Fig. 2. Control system diagram
1) the transfer function of electro-hydraulic servo valve the servo valve gain is defined as follows: KV =
3 −1 QV 1.05 × 10−3 = = 3.5 × 10−2 m /s ⋅ A IV 0.03
(2)
Dynamic parameters of servo valve are decided in accordance with sample values, and natural frequency ωV is 340 rad / s, damping ratio ξV is 0.70, so the transfer function expression can be prescripted as follows:
QL 3.5 × 10−2 = 2 s 2 × 0.7 I + s +1 2 340 340
(3)
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2) The transfer function of hydraulic motor By calculation, the total volume of motor oil cavity and the volume between servo −6 3 valve to the motor is Vt = 50 ×10 m , effective volume elasticity coefficients β e = 7000 × 105 Pa ,So natural frequency expression of motor can be defined as follows:
ωh =
4β e Dm2 = 193 JVt
(4)
and damping ratio ξ h = 0.2, then the transfer function of hydraulic motor can be shown as follows: 1 0.62 × 105 × 163 10 −7 = 2 = 2 2 × 0.2 2 × 0.2 s s QL + + s +1 s +1 1932 193 1932 193
θ m'
(5)
3) Transfer function of velocity sensor determination Static gain of velocity sensor is 20 V/r ⋅ min −1 ,
KT
= 0.02 V/r ⋅ min −1 = 0.19
V·s/rad transfer function of integral amplifier is defined as follows: I Ka = ue S
(6)
2.5 Integral Amplifier Gain Determination Transfer function of open loop system is defined as follows:
W (S ) =
Ka × 3.5 ×10−2 × 0.62 ×105 × 0.19 ⎛ s2 ⎞⎛ s 2 ⎞ 2 × 0.7 2 × 0.2 s⎜ s s + 1⎟ 1 + + + ⎟⎜ 2 2 340 193 ⎝ 340 ⎠⎝ 193 ⎠
(7)
K = K a × 3.5 × 10 −2 × 0.62 × 105 × 0.19 = 2170 Ka
Gm is the stable amplitude margin, Wcg is the crossover frequency of the corresponding phase; pm is phase margin, Wcp is the Based on Bode diagram of the system,
crossover frequency of the corresponding amplitude. For the control engineering practice, stability margin must be ensured, so the parameters of the system are prescribed as follows: Gm > 6dB, that is: Gm > 2; pm ≥ 30, The system is single input-output system, the program was designed as follows:
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F. Lin sum = [K]; den1 = [1/340^2 1.4 /340 1 0 ] ; den2 = [0 1 /193^2 0.4 /193 1 ] ; den = conv(den1,den2); sys =tf(sum,den);
[Gm , pm , Wcg ,Wcp ] =margin(sys) The results are shown as follows: Table 1. Results of the program operation
In this paper, K =36.9 based on the analysis of table 1,and so there be:
Ka =
36.9 = 0.089479 3.5 × 10 × 0.62 × 105 × 0.19 −2
(8)
Transfer function of open loop system was shown as follows:
W (S ) =
36.9 ⎛ s ⎞ ⎛ s2 ⎞ 2 × 0.7 2 × 0.2 + + s⎜ s + 1⎟ ⎜ s + 1⎟ 2 2 340 193 ⎝ 340 ⎠ ⎝ 193 ⎠
(9)
2
2.6 The Steady-State System Error
The open loop system is 1 type system because the introduction of an integral part. The error of system response to velocity instruction is zero, which can fully meet the tracking accuracy requirements of ± 1 r / min. 2.7 System Simulation and Results
System simulation diagram is shown by Fig. 3. and simulation results of system response to step signals is shown by Fig. 4.
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Fig. 3. System simulation diagram
Fig. 4. Simulation results of system response to step signal
The simulation results show that the existing system is stable and non-overshoot, the increasing process was not monotonous, with a few small oscillations. the transition process within 0.11 s, and quickly reach convergence. so the system can complete the tracking task accuratly within 0.5s, the volecity control system design is meet the requirements very well.
3 Conclusion 1) In the velocity control system designing, relatively stable amplitude margin, phase margin, the crossover frequency of the corresponding phase and reasonable system parameters can be easy to calculated accurately based on the simulation of open loop system use matlab language. 2) Simulation on the designed system using matlab/simulink can predict the results, verify correctness and provide a reference for designers. Availability of the simulation results depends on the correctness of the mathematical model, so rational model and parameters selection of the system are important. Acknowledgement. This work was sponsored by Supported by Foundation of Jiangxi Educational Committee(GJJ09210).
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References 1. Li, H.: Hydraulic control system. National Defence Industry Press, Beijing (February 1981) 2. Wang, C.: Hydraulic servo control system. China Machine Press, Beijing (1993) 3. Eryilmaz, B., Wilson, B.H.: Unified Modeling and Analysis of a Proportional Valve. Journal of the Franklin Institteu 343(1), 48–68 (2006) 4. Liu, J.-R., Jin, B., Xie, Y.-J., Chen, Y., Weng, Z.-T.: Research on the electro- hydraulic variable valve actuation system based on a three-way proportional reducing Automovalve. International Journal of tive Technology 10(1), 27–36 (2009) 5. Guan, J.T.: Electro hydraulic Control Technique. Tongji University Press, Shanghai (2003) 6. Wang, C.: Electro-Hydraulic Servo Control System. China Machine Press, Beijing
Application of Background Information Database in Trend Change of Agricultural Land Area of Guangxi Xin Yang1,*, Shiquan Zhong1,2, Yuhong Li1,2, Weiping Lu1,2, and Chaohui Wu1,2
1
Remote Sensing Application and Test Base of National Satellite Meteorology Centre, Nanning, China, 530022 2 GuangXi Institute of Meteorology, Nanning, 530022, P.R. China Tel.:+86-771-5875207; Fax: +86-771-5865594 [email protected]
Abstract. Guangxi Province is one of the regions more serious desertification. This paper using ENVI image processing system, according to remote sensing image interpretation target mark and image spectral characteristics, found remote sensing interpretation model of the background information of forest, shrub and grass, agricultural land, surface water, towns, roads from TM and ETM data from 1988 to 2008, using supervision, unsupervised, maximum classification of natural law to retrieve background information from simple to complex interpretation of each classification. Meanwhile, using human-computer interaction to refine the results. The output shp format data Vector file of disaggregated data edited in the GIS system, and get the background information on various types of remote sensing data each time. The result showed that agricultural land area showed a decreasing trend, but change is not very significant. Keywords: background information, agricultural land area, trend change.
1 Introduction China's natural resources, especially arable land resources is one of the major constraints facing severe shortage of long-term survival and development. The constant decrease of cultivated land resources arouses the extensive attentions of society at home and abroad. As the increasingly urgent problem of food security, urbanization and agricultural development and environmental pressure on the contradictions, land *
Corresponding author.
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resource protection to ensure national food security has become an important basic work. With the development of satellite remote sensing technology, remote sensing has become an important means of land access to information. Many studies on land use/cover changes had been carried out by researchers from all over the world since the first earth resource satellite was launched in 1970s in the United States. Land use/cover maps for the urban area of Boston were produced at level of Anderson et al. (1972) scheme using large format camera shuttle photographs and national high altitude photographs. The accuracy of them was 65% and 70% respectively (Lo & Noble, 1990). The potential of SPOT XS images were tested for automatically outlining agricultural near-urban interfaces for an area around Yogyakarta, Central Java, and satisfying results were gotten which were comparable to those obtained from visual interpretation of 1:100000 near-infrared aerial photographs (GastelluEtchegorry, 1990). Eight land covers were mapped at level of Anderson scheme on the urban fringe in England from Landsat MSS data (Curran & Pedley, 1990). 10 m resolution of the SPOT panchromatic band was used by registering it with the multispectral ones to obtain a classification of eight land covers at the urban- rural fringe of Toronto, Canada with an accuracy of 78% (Treitz et al., 1992). Five-category classification was obtained in the small urban area of Beaver Dam, Winsconsin (Harris & Entura, 1995). Detailed land cover maps were produced at the urban-rural periphery in southern Auckland using Spot XS data (Gao & Skillcorn, 1998). Using TM imagery residential areas were extracted with simple threshold of spectrum structure (Yang & Zhou, 2000). From TM imagery using normalized difference built-up index, the urban land-use map of Wuxi city was achieved (Zha, 2003). The present paper using ENVI image processing system, according to remote sensing image interpretation target mark and image spectral characteristics, found remote sensing interpretation model of the background information of forest, shrub and grass, agricultural land, surface water, towns, roads from TM and ETM data from 1988 to 2008, using supervision, unsupervised, maximum classification of natural law, from simple to complex interpretation of each classification. Meanwhile, using humancomputer interaction to refine the results. The output shp format data Vector file of disaggregated data edited in the GIS system, and get the background information on various types of remote sensing data each time.
Ⅲ
2 Materials and Methods 2.1 Study Area Guangxi (104°28′-112°03′E, 20°54′-26°23′N), a city in South China, has an area of about 236,700 km2 (Fig.1). It belongs to the Subtropical monsoon climate region, annual average temperate is 16.0 -22.0 , and annual mean precipitation is 1200-1800mm.
℃
℃
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Fig. 1. Location of study area
2.2 Data Acquisition In this study, Landsat ETM/TM images from 1986 to 2008 were required. List of the orbit data is in Table 1, and their spatial resolution is 30 m. Table 1. List of the orbit data
Orbit data Image Time(TM) 123/43 1988-12-07 123/44 1988-12-17 124/42 1986-11-01 124/43 1986-11-01 124/44 1986-11-01 124/45 1986-11-01 125/42 1987-10-26 125/43 1987-10-26 125/44 1986-11-24 125/45 1988-11-29 126/42 1988-09-17 126/43 1988-10-19 126/44 1986-10-30 126/45 1988-03-07 127/42 1988-11-11 127/43 1988-11-11 127/44 1988-11-11 128/43 1987-03-21
Image Time(TM) 1991-09-09 1994-05-08 1998-10-01 1998-10-01 1998-10-17 1998-10-17 1998-10-24 1998-10-24 1998-10-24 1998-10-24 1999-09-24 1998-10-15 1998-10-15 1998-10-15 1998-11-07 1998-11-07 1998-11-07 1997-11-27
Image Time(ETM) 2001-12-29 2001-12-29 2002-01-05 2002-01-05 2002-01-05 2001-11-18 2001-11-25 2002-10-11 2002-10-11 2002-10-11 2002-08-31 2002-08-31 2001-11-16 2001-09-29 2001-11-23 2001-11-23 2001-11-23 2002-04-07
Image Time(TM) 2006-12-19 2006-12-19 2008-11-13 2008-11-13 2008-11-13 2008-11-13 2008-05-12 2008-05-12 2008-11-20 2008-11-20 2008-11-27 2008-11-11 2008-11-11 2008-11-11 2008-12-20 2008-03-23 2008-03-23 2006-04-10
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2.3 Data Processing The basic idea of this research was to retrieve forest, shrub and grass, agricultural land, surface water, towns, Rocky Desertification, roads of different image phases using Landsat ETM/TM data, and then to map the agricultural land , finally to analyse the trend of agricultural land change (Fig. 2).
Fig. 2. The flow chart of background information of remote sensing classification
Detailed illustration of data processing was as follows: • Imagery pre-processing The pre-processing included atmospheric correction, geometric correction, and orthographic correction. The purpose of atmospheric correction was to obtain accurate reflective characteristics of ground surface, followed by geometric correction which ground control points were chosen referencing to a topographic map of 1:50,000. To efficiently reduce the topographic effect on solar radiation, DEM was employed to promote orthographic correction on remote sensing images. • Retrieval of background information In this research, supervision, unsupervised, maximum classification of natural law were used to retrieve background information. • Mapping background information of Guangxi Background information were mapped by using supervision, unsupervised, maximum classification of natural law. Then the change of agricultural land area from 1986 to 2008 can be acquired.
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3 Retrieval of Background Information Classes From the spectrum feature of ground, band 4 (0.76-0.90μm) of TM/ETM+ is the near infrared waveband which reflects vegetation information. Thus this band is very sensitive to detect vegetation, while reflectance of barren and residential areas in this band is low. ETM/TM5 (1.55-1.75μm), the shortwave infrared waveband, can reflect the information of moisture content in different land use types. For example, in band5 the reflectance of forest and farmland with high moisture content is low, but for residential and barren areas that have low moisture content, the reflectance is high. Researches indicated that on Landsat TM/ETM+ images, except urban and barren areas,the digital numbers of other landscape in band 4 are lower than that of band 5 (Yang, 2000, Zha, 2003).Supervised classification is the most common method in obtaining land use/cover information. In this research, after data pre-processing, training samples were selected according to the band spectral curves of target objects(Fig.3).
Fig. 3. Band spectral curves of target objects
Unlike conventional classification of land use/cover, in this paper, only six classifications of land cover were chosen, which were forest, shrub and grass, agricultural land, surface water, towns, roads . At the same time, we use human-computer interaction to refine the results. This could avoid the background information classes(Fig.4). Then maximum likelihood classification was used to map the agricultural land of Guangxi(Fig. 5).
Fig. 4. Background information classes
Fig. 5. Distribution of agricultural land
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It can be seen from the report provided by the software of ENVI, the overall accuracy of classification can be acquired (Table.2). Fig. 6 is the field survey itinerary. Table 2. Accuracy analysis of classification results
Classes forest Shrub and grass Agricultural land Surface water towns roads
Total survey Correctly classified 26 22
Accuracy (%) 84.62
106
94
88.68
42
37
88.09
28
26
92.86
50 46
43 38
86.00 82.60
Fig. 6. Field survey itinerary
Fig.7 is the area of agricultural land of Guangxi from 1988 to 2008.
Fig. 7. Area of agricultural land
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4 Discussion and Conclusion By analyzing the change of agricultural land area of Guangxi from 1986 and 2008 resulted from supervised classification, we can find that during the 20 years, agricultural land area has decrease 732.8km2 from 42767.3km2 to 42034.5km2, showed a decreasing trend, but the change is not very significant. This change was driven by many factors. however human activity was the most important one. Rapid economic development and fast urbanization was the fundamental reasons. A lot of farmland were used to build large scale constructions of infrastructures.
Acknowledgments This research was supported by Scientific Research and Technological Development projects of Guangxin Province (0816006-8) and National 11th Five-Year Plan major scientific and National Key Technologies R&D Program (2008BAD08B01), Sincerely thanks are also due to Guangxi Climate center and National Satellite Meteorology Center for providing the data for this study.
References 1. Bruzzone, L.: Detection of changes in remotely-sense images by the selective use of multispectral information. Int. J. Remote Sensing 18, 3883–3888 (1997) 2. Curran, P.J., Pedley, M.I.: Airborne MSS for land cover classification II. Geocarto International 5, 15–26 (1990) 3. Charbonneau, L., Morin, D., Royer, A.: Analysis of different methods for monitoring the urbanization process. Geocarto International 8, 17–25 (1993) 4. Chen, X.J., Zhang, H.Y., Liu, S.H.: A study on the macro mechanism of the conversion of land use in the urban fringe of Beijing. Progress in Geography 22, 149–157 (2003) (Chinese) 5. Dai, C., Lei, L.: The Information Characteristics of Thematic Mapper Data and the Optimal Band Combination. Remote Sensing of environment 4, 282–292 (1989) 6. Gao, B.C.: NDVI-a normalized difference water index for remote sensing of vegetation liquid water from space. Remote Sensing of Environment 58, 257–266 (1996) 7. Gao, J., Skillcorn, D.: Capability of SPOT XS data in producing detailed land cover maps at the urban-rural periphery. International Journal of Remote Sensing 19, 2877–2891 (1998) 8. Gastellu-Etchegorry, J.P.: An assessment of SPOT XS and Landsat MSS data for digital classification of near-urban land cover. International Journal of Remote Sensing 11, 225– 235 (1990) 9. Harris, P.M., Ventura, S.J.: The integration of geographic data with remotely sensed imagery to improve classification in an urban area. Photogrammetric Engineering and Remote Sensing 61, 993–998 (1995) 10. Lo, C.P., Noble Jr., E.: Detailed urban land-use and land-cover mapping using large format camera photographs: an evaluation. Photogrammetric Engineering and Remote Sensing 56, 197–206 (1990)
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11. Mcffters, S.K.: The use of the Normalized Difference Water Index (NDVI) in the delineation of open water features. International Journal of Remote Sensing 17, 1425–1432 (1996) 12. Sidjak, R.W., Wheate, R.D.: Glacier mapping of the Illecillewaet icefield, British Columbia, Canada, using Landsat TM and digital elevation data. International Journal of Remote Sensing 20, 273–284 (1999) 13. Treitz, P.M., Howarth, P.J., Gong, P.: Application of satellite and GIS technologies for land-cover and land-use mapping at the rural-urban fringe: a case study. Photogrammetric Engineering and Remote Sensing 58, 439–448 (1992) 14. Xu, H.Q.: Spatial expansion of urban/town in Fuqing and its driving force analysis. Remote Sensing Technology and Application 17, 86–92 (2002) 15. Yang, C.J., Zhou, C.H.: Extracting residential areas on the TM imagery. Journal of Remote Sensing 4, 146–150 (2000) 16. Yang, S.: On extraction and fractional of urban and rural residential spatial pattern in developed area. Acta Geographical Sinica 55, 671–678 (2000) 17. Zha, Y., Gao, J., Ni, S.: Use of normalized difference built-up index in automatically mapping urban areas from TM imagery. Int. J. Remote Sensing 24, 583–594 (2003) 18. Zha, Y., Ni, S., Yang, S.: An effective approach to automatically extract urban land-use from TM imagery. Journal of Remote Sensing 7, 37–40 (2003)
Reasons of the Incremental Information in the Updating Spatial Database Huaji Zhu, Huarui Wu*, and Xiang Sun National Engineering Research Center for Information Technology in Agriculture, Beijing, 100097, P.R. China [email protected]
Abstract. In order to quickly extract and distribute the incremental information of spatial database, this work analyses the reasons of incremental information of spatial database with the instance of residential feature. Firstly, a new concept of increment is proposed based on the spatio-temporal change type and data delta. The change type describes the semantics of increment information and data delta describes the content of increment information. Based on this concept, the types of residential change and relevant data deltas are put forward. There are two catalogs of change type, i.e. subjective change and objective change. The subjective change can be detailedly divided into 3 small change types and the objective change can be detailedly divided into 12 small change types. Additionally, the incremental information resulted from the objective change is formalized. Based on the above formalized changes, the automatic extraction of incremental information can be expediently programmed. The classifying result was applied to the incremental information automatic extracting system of 1.250,000 topographic databases. Keywords: Incremental Information, Spatio-temporal change, Subjective changes, Objective changes.
1 Introduction How to distribute the new data in the updated topological database is becoming a hot topic in GIS domain [1,3]. Currently, the new data of topological database is distributed by the batch method which has such problems as the data volume distributed is very big and users are difficult to integrate the distributed data in their database [2, 4, 6]. According to the Stat. by Raynal [3], the change rate every year of the geographical objects in a geographical database is about 10%. For instance, comparing to the 1998 version of the 1.250000 topographical database (a kind of special geographical database), the change rates of all kinds of topographical feature in 2002 version of the same database are respective 9.7% for water feature (2.4% every year), 27.9% for district boundary feature (7% every year), 20.9% for road feature (5.2% every year), 34.4% for point residential feature (8.6% every year) and 75.3% for area residential feature (18.8% every year). According to above percentages, we can find that most features’ change rates every year *
Corresponding author. Tel.: +86 10 51503594; Fax: +86 10 51503594.
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are less than 10% except for the area residential feature.If the batch method is used, about 90% distributed data are invalid. In practical, users only focus on the changed data in the updated database, i.e. the data delta between old version and new version of the same database. So providing data delta not the whole new updated database can overcome above mentioned problems in the batch method [8, 9, 10]. Data delta result from the change in real world. Different change results in different data delta, that is to say, every change type is corresponding to certain data delta. If only data delta is provided, the users sometimes don’t know how to integrate the data delta in their database without knowing the reasons (change type) of the data = -[OID, O.A.V, O.S.G] denotes a deleted residendelta. For instance, data delta tial feature O, OID denotes the ID of O, O.A.V denotes the attribute set of O, O.S.G denotes the graphics of O. Several reasons can result in the data delta . For instance, one reason is the disappearance of a residential feature in the real world. The second reason is that the area of a residential feature is less than the area threshold of certain scale because of shrinking. In the certain scale database, a feature can be collected in the database if its area is more than or equal to the area threshold, otherwise the feature should be abandoned[11, 12]. However, the problem will completely vanish if data delta and its change type are provided together. In this work, we call the combination of data delta and change type as increment.
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2 Relationship between Change and Increment The relationships among change, data delta and increment are showed in Fig.1.
Real world
Data collection
Geographical
Representation
Data world K
…
entity K Change Update
Change
Geographical
Representation
K
Data delta
…
entity K
Fig. 1. The relationship among change, data delta and increment
Firstly, we explain the concept “geographical feature”. The concept commonly is called as geographical entity in the real world and as geographical object in the data
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world. The changes of geographical entities in the real world or the changes of data collection standards may result into update operations which modify the content of the database and produce the data delta. The data delta resulted from every update operation is exclusive and certain. However, different change types correspond to different update operations. So the different change produces different data delta. In this paper, we define 4 kinds of update operations and relative data delta. The 4 update operations are object deletion, object creation, graphics update and attribute update. The data delta of the object deletion is ={-[OID, O.A.V, O.S.G] }. The data delta of the object creation is ={+[OID, O.A.V, O.S.G] }. The data delta of the graphics update is ={O.S.G/+G’}, G is the value before change, G’ is the value of after change. The data delta of ={O.A.-V/+V’}, V is the value before change, V’ is the value the attribute update is of after change. By establishing the certain relationship between the change type and the set of update operations, the data delta of every change can be exclusively decided. So the increment which is composed of change type and data delta can be decided.
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△
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3 Reasons of Increment There are two reasons to generate the increment information, subjective reason and objective reason. The objective change is the changes of geographical features in the real world. The subjective changes result from the change of data model, the defined attribute set of every feature and so on. 3.1 Subjective Changes There are three kinds of subjective changes, the changes coming from the errors amendment, the changes coming from the change of correction rules and the change of database scheme. subjective changes of spatial data are ruleless and have no uniform expression. The errors amendment may generate the data delta. For example, the grade of a road is amended from the national road to provincial road. The data delta is 200542. Grade.-“national road”/+“provincial road”. The 200542 is the ID number of road. The increment information is [error amendment,update, 200542.Grade.-“national road”/+“provincial road”]. The change of correction rules may generate data delta. For example, the district feature has the attribute of district code. The rule of the district code is different between the old database and new database. For example, the old district code of the “Zhuo zhou city” is 121024, but the new district code is 132402. In fact, the “Zhuo zhou city” has no change. But because the change of the code rules, the feature generates some increment information. Another example, in the old data of the 1.250000 topological database, the database field ‘FName’ denotes the name of the feature. The values of ‘Fname’ don’t include the district grade. But in the new data of the 1.250000 database, the values of ‘Fname’ include the district grade. For instance, a village is called as “Chang Cao” in old data but is called as “Chang Cao Cun” in the new data.
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The change of database scheme also may generate increment information. The topological database is established based on a data scheme. The database can be established based many kinds of data scheme. In the scheme, the attribute set of every feature can be changes according to the real world. So, the scheme of a topological database often changed. For example, the residential feature has a field “PYNAME” in the old data of the 1.250000 topological database. But in the new data, the field “PYNAME” is deleted. 3.2 Objective Changes There are many kinds of objective change in the real world. [4, 5] defined the event types expressing the changes. In the real world, different geographical feature with the same event may generate different changes. So, we give a new change expression based on the event type and the data delta. In this work, we only consider the simple events, that is to say, the event which affects an attribute of the geographical feature. But in the real world, there are many complex events. We can compound the generated events based on the changes of the simple events. According to the alterant extent, the event affected the change is divided into the evolution event and the death/birth event. The death/birth event can cause the appearance of new feature or the disappearance of old feature. The evolution event may cause the change of the characteristics of feature. The evolution event can be future divided into spatial evolution event and theme evolution event. [4, 5] defined eight kinds of death/birth event, including appearance, disappearance, split, unite, reallocate, replace and produce. Based on the practical facts, we define six kinds of death/birth event, including appearance, disappearance, divide, split, unite, and merge into, as showed in Fig.2, the &n in figure is the identification ID.
&2
&1
&3 (a) disappearance
&6
(b) appearance
&2
&5
(c) divide
&7
(d)
&9
split
&8
&4
(e)
&10
&5 merge into
&12
&13
&11 (f)
unite
Fig. 2. The change process resulted from the birth or death events
Different death/birth processes correspond to different update operations. This means the different death/birth processes generate different increment information.
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The Fig.2 shows six kinds of increment information. In Table 1, the increment information and update operations resulted from the death/birth changes are given. For instance, Fig.2 (a) is the disappearance process, the update operation is “Delete” and the data delta is = -[&1, &1.A.V, &1.S.G]. The increment information is Increment=[disappearance,delete &1,-&1]. Fig.2 (b) is the appearance process, the update operation is “Create” and the data delta is = +[&6, &6.A.V, &6.S.G]. The increment information is Increment=[appearance,create &6,&6.A.V,&6.S.G]. Table 1 shows the increment information and update operation of death/birth evenets.
△
△
Table 1. The increment resulted from the birth or death evenets Change type
The instance of
Update operation
Increment information
change Appearance
&6 Appearance
{Create &6}
Appearance,Create &6,+[&6,&6.A.V,&6.S.G]
Disappearance
&1 Disappearance
Delete &1
Disappearance,Delete
&10 ǃ &11 ǃ &12
Create
Unite
&10,Delete &11,Delete
&12},{ ˉ &10, ˉ &11, ˉ &12,+[&13, &13.A.V,
&12
&13.S.G]}
Unite
Merge into
as &13
&4 Merge into &5
Split
&7Split into &8 and &9
&13,Delete
&1,ˉ&1
Unite,{ Create &13,Delete &10,Delete &11,Delete
Update the Graphics of
Merge into,{ Update the Graphics of &5,Delete
&5,Delete &4
&4},{ˉ&4,&5.S.ˉG/+G’}
{Create &8 and &9,
Split,{Create
Delete&7}
&8.A.V1, &8.S.G1],+[&9, &9.A.V2, &9.S.G2], ˉ
{Create &3,Update the
Divide,{Create
Graphics of &2}
&2},{+[&3, &3.A.V1, &3.S.G1],&2.S.ˉG/+G’}
&8,Create
&9,Delete
&7},{+[&8,
&7} Divide
&3 is divided form &2
&14
&15
&3,Update
the
Graphics
of
&15
&14 (a)
(b) expand
move
&16
&16
&17
&17
&18 (c) contraction
&18 (d)
incomplete merge into
Fig. 3. The change process resulted from the spatial evolution events
[4, 5] defined seven kinds of evolution event, including move, deformation, contraction, rotation, discoloration, density increase and texture change. Based on the
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practical facts, we define four kinds of evolution event, including move, contraction, expand and incomplete merge into, as showed in Fig.3, the &n in figure is the identification ID. Table 2 shows the increment information and update operation of evolution evenets. Table 2. The increment resulted from the evolution events Change
The instance of change
Update operation
Increment information
type expand
The area of Geographical
Create &15
Expand, Create
feature &15 increases. (&15
&15,+[&15, &15.A.V, &15.S.G]
doesn’t exist in the old database) expand
The area of Geographical
Update the graphics of
Expand, Update the graphics of &15, &15.S.ˉ
feature &15 increases. (&15
&15
G/+G’
The area of Geographical
Update the graphics of
contraction, Update the graphics of &16, &16.S.
feature &16 decreases. (&16
&16
ˉG/+G’
Delete &16
Contraction , Delete
Update the graphics of
move, Update the graphics of &14 ,&14.S.ˉ
&14
G/+G’
exists in the old database) contraction
exists in the new database) contraction
The area of Geographical
&16,-&16
feature &16 decreases. (&16 doesn’t exist in the new database) move
The
position
geographical
of
feature
a &14
moves east 600m. incomplete
&18 incomplete merge into
Update the graphics of
incomplete merge into, { Update the graphics of
merge into
&17
&17,
&17, Update the graphics of &18},{ O1.S.ˉ
Update
graphics of &18
the
G1/+G1’,O2.S.ˉG2/+G2’ }
Current researches can’t give the change type of attribute event. Based on the practical facts, we define two kinds of attribute change, i.e. the relative attribute change and the generic attribute change, as showed in Fig. 4. Table 3 gives the increment information of the attribute change.
Nanshiliju Town Liyuan &19 31080
grade change
Liyuan Cun &19 31091 (a)
&20
Dongfeng Town Name change
&20 (b)
Fig. 4. The change process resulted from the attribute evolution event
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Table 3. The increment resulted from the attribute evolution processes Change
The instance of
type
change
Update operation
Increment information
grade change
The grade of &19
Update the Grade and
The grade change, Update the Grade and Name Field
changed from town
Name Field of &19
of &19,{&19.Grade. ˉ 31080/+31091,&19.Name. ˉ
to village
Name change
Liyuang Town/+Liyuan Village}
The Name of &20
Update the Name Field
Name change, Update the Name Field of &20 ,
changed
of &20
O.Name.ˉNanshiliju Town /+ Dongfeng Town
from
‘Nanshiliju Town’ to ‘Dongfeng Town’
4 Application to the Case Study Based on the above method, we developed software to extract the increment information. The core component of the software is the rule database. The rules are established according to the change type and the corresponding increment information. Every change type can be expressed as one or more rules. For example, the “Expand” of the residential feature can be expressed two rules. Fig. 5 gives some instances of increment information. Rule 1. IF feature R has the change “Expand” And R exists in the old database Then increment information=[ Expand, Update the graphics of R, R.S. G/+G’].
-
Rule 2. IF feature R has the change “Expand” And R doesn’t exist in the old database Then increment information=[ Expand, Create R, +[R, R.A.V, R.S.G]] Old data
New data
Increment information
TN: 245781,GB:31090,
TN: 245781,GB:31090,
Expandˈ
Name: Dongfeng Town,
Name: Dongfeng Town,
Update the graphics of 245781
Change type: Expand TN: 240241,GB:31090,
Expandˈ
Name:Dali village,
Create 240241ˈ
Change type: Expand
[TN:240241,GB:31091, Name: Dali village,
]
Fig. 5. The instances of increment information
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The flow of the software is divided into 6 steps. 1) Load data. Load the old and new data of the same feature and same area. 2) Data pretreatment. check the invalid data and amend it. 3) Compute change types. based on the old and nssew data, extract the change types of every feature. 4) Correspond rules. find the rules from database based the change types. 5) Extract increment information
5 Conclusions The focus of this work was on how to help the exchange of updating information between a spatial data producer and a user. In order to more clearly distinguish the increment change of geographical object, we analyses the increment information of the geographical feature. A new model of increment information is proposed based on the spatio-temporal change type and data delta. The model not only clearly represents the semantics of change but also describes the data delta of change. Based on the model, we can get the reason of the change. In this work, we define 15 kinds of change type, including 3 kinds of subjective change and 12 kinds of objective change. And the increment information expressions of every change are given. The method can be used to extract the increment information. But the method proposed in this work can’t be used to express the increment information of subjective change.
Acknowledgment This paper is supported by a grant from Beijing Nova program (Grant No. 2009B26), a grant from Beijing Academy of Agriculture and Forestry Sciences for Young Scholars and the National Natural Science Foundation of China (Grant No. 60871042).
References [1] Badard, T., Richard, D.: Using XML for the exchange of updating information between geographical information systems. Computers, Environment and Urban Systems, 17–31 (2001) [2] Badard, T.: Towards a generic updating tool for geographic databases. In: Proceedings of GIS/LIS 1998, Annual Conference and Exposition, Fort Worth, TX (1998) [3] Raynal, L.: Some elements for modelling updates in topographic databases. In: Proceedings of GIS/LIS 1996, Annual Conference and Exposition, Denver, Colorado, USA (1996) [4] Claramunt, C., Thériault, M.: Toward Semantics For Modeling Spatio-Temporal Processes, Within GIS. In: Advances in GIS II(SDH 1996), The Netherlands. Taylor and Francis, Abington (1996) [5] Shu, H.: Principles of Conceptual, Formal and Logical Spatio-temporal Data Modeling, Wuhan, Docter Dissertation of Wuhan Technical University of Surveying and Mapping (1998) (in Chinese)
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[6] Zhou, X.G., Chen, J., Zhu, J.J.: Event-based Incremental Updating of Spatio-Temporal Database. Journal of Image and Graphics 11(10), 1431–1438 (2006) (in Chinese) [7] Xia, Y., Zhu, X.Y., Guo, W.: Research on spatial data version management based on ArcSDE. Computer Engineering and Applications 43(14), 14–16 (2007) (in Chinese) [8] Spéry, L., Claramunt, C., et al.: A Spatio-Temporal Model for the Manipulation of Lineage Metadata. Geoinformatica 5(1), 51–70 (2001) [9] Badard, T., Richard, D.: Using XML for the exchange of updating information between geographical information systems. Computers, Environment and Urban Systems 25, 17– 31 (2001) [10] Lin, Y., Liu, W.Z., Chen, J.: Modeling spatial database incremental updating based on base state with amendments. In: Proceedings of the International Conference on Mining Science & Technology (ICMST 2009), Xuzhou, China (2009) [11] Wang, N., Xu, H.B., Wang, N.B.: Incremental Maintenance of Global Templates in Heterogeneous Data Integration System. Journal of Software 10(4), 382–389 (1999) (in Chinese) [12] Claramunta, C., Parent, C.: Modelling concepts for the representation of evolution constraints. Computers, Environment and Urban Systems 27, 225–241 (2003)
Research on Non-point Source Pollution Based on Spatial Information Technology: A Case Study in Qingdao Tao Shen1, Jinheng Zhang2,*, and Junqiang Wang3 1 College of Surveying and Mapping & Urban Spatial Information, Beijing University of Civil Engineering and Architecture Beijing, China, 100044 2 Institute of Eco-environment & Agriculture Information, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China [email protected] 3 Qingdao Station for Popularizing Agricultural Techniques, Qingdao, Shandong 266000, China
Abstract. The paper discussed the research course of the non-point source pollution and the application of spatial information technology to the non-point source pollution. Then we collected some spatial information data such as terrain, soil, water system, land use and so on, used MUSLE equation supported by geographic information system to get the risk distributing map of the non-point source pollution in Qingdao. The study met with good results. The result showed that the spatial information technology is a powerful tool to research the non-point source pollution and it can powerfully provide the decision support for management and control of the non-point source pollution. Keywords: non-point source pollution, modified universal soil loss equation, spatial information technology.
1 Introduction Non-point source pollution refers to the atmosphere, surface and soil pollutants (municipal solid waste, rural livestock manure, chemical fertilizers in farmland, pesticides, heavy metals and other toxic substances or organic compounds) take the rain as the carrier and migrate to the surface runoff in the process of runoff generation and conflux under the action of eluviation and erosion of the rainfall runoff, thereby coming into receiving waters such as rivers, lakes, reservoirs, ocean waters and so on and causing pollution[1]. At present, the control and management of the point source pollution such as industrial and living pollution has gradually strengthened and achieved remarkable results as people deepened understanding of the importance of their hazards, and non-point source pollution impacting on the environment have become increasingly prominent[2]. Currently, many studies have confirmed that non-point source pollution *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 592–601, 2011. © IFIP International Federation for Information Processing 2011
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has become the major sources for the world-wide surface water and groundwater pollution, such as in the United States, there are approximately 60% pollution of the rivers and 50% pollution of the lakes related to the non-point source pollution[3]. In China, non-point source pollution is increasingly serious, the non-point source pollution in Taihu Lake and Dianchi Lake has become one of the important causation of the main lake water quality deterioration[4]. The study of the non-point source pollution in foreign started in the 50 to 60 years of the 20th century and the United States, Britain, Japan and other developed countries take the lead in this study. Particularly in the United States, there is a long research history, the United States is on of the few countries in the world carrying out the national system control study of the non-point source pollution[5]. The U.S. Department of Agriculture and other research institutions have developed a series of experience statistical model foe agricultural non-point source pollution, including SCS curve code and universal soil loss equation (USLE)[6]. In the late 90s of the 20th century, a number of very large and powerful watershed model has been developed. These models are all large professional software integrated spatial information processing, database technology, mathematical calculation and visualization. In these models, more well-known are the BASINS developed by the United States Environmental Protection Agency, the SWAT[7] developed by Arnold and the AnnAGNPS jointly developed by the U.S. Natural Resources Conservation Service and Agricultural Research Service. These models are widely used in the study of the continuous simulation to the regional rainfall - runoff, soil erosion and solute transport. They can be used to estimate the pollution load in order to identify the main pollution factors and critical source areas, and combined with the control and management measures. The study of the non-point source pollution in China began in the late 80s of the 20th century. In this period, the study mainly focus on the study in the macroscopic characteristics, the pilot study in quantitative model of the agricultural non-point source pollution load[8] and the investigation of the lake eutrophication. As our country is not enough aware of the harm of the non-point source pollution, moreover the study of the non-point source pollution disjoints with the total amount control programs of the pollutants from the non-point source pollution, research means of our country isolated, scattered and mainly in the field of artificial simulation study and experiment on spot[9], and the non-point source pollution control measures are very weak. Although some studies have dealt the content of non-point source pollution load assessment, modeling and GIS integration technology [10], there are very few participants, lack systematic research and do not extend deep into the management and policy research. In recent years, with the understanding of non-point source pollution, the level of our study is also rising. The research on urban runoff pollution in Beijing [11] and the following study in the Yuqiao reservoir, Dianchi Lake, Taihu Lake, Chaohu Lake, Jinjiang River, Suzhou River, the Miyun Reservoir achieved fruitful results and accumulated useful experience [12-16]. Spatial information technology is a new technology rising in the 60 years of this century and developed rapidly in China after mid-70s, which mainly includes the theories and technologies of the remote sensing (RS), geographic information systems (GIS), Global Positioning System (GPS), and combined with computer technology and
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communication technology. This technology puts up spatial data collection, measurement, analysis, storage, management, display, dissemination and application. With the development and wide application of spatial information technology, remote sensing and geographic information systems has become an important research technology of non-point source pollution. Remote sensing and geographic information systems can provide the accurate spatial information to monitor non-point source pollution and provide the surface characteristics of the the location of pollution. Remote sensing can also provides land use, vegetation cover DEM and other basic data to various non-point source pollution model, geographic information systems has strong spatial and temporal advantage in managing and analyzing geographic data, GPS data, soil data, weather data, environmental data, remote sensing data and agricultural management data. The study of non-point source pollution often requires large quantities of measured data, but nowadays the information available to both quantity and quality are still not satisfied, a lot of information to rely on field measurements is very difficult to study[17]. The emergence of remote sensing technology provides an effective means to solve these problems and creates favorable conditions for the development of these models because remote sensing is macroscopic, short-periodic and human, material, financial, and time savings. Geographic information system has powerful data processing capabilities, enabling people to analyze and process the geo-spatial data collected by the RS technology, and promote the development of the model. Non-point source pollution combined with RS and GIS technology has become a current focus of international research.
2 The Research Process It is an effective technique to use the spatial information model to analyze the spatial and temporal distribution of non-point source pollution. USLE, the widely applied empirical model since the 60 years of the 20th century, only requires a few parameters to effectively describe and evaluate the non-point source pollution distribution after integrated with GIS. Sivertun[18] developed a modified USLE model(MUSLE) to achieve the rapid identification of risk areas of the non-point source pollution on the GIS platform, and so extended the USLE applications. In this paper, we make Qingdao as the research object and use MUSLE model to study the non-point source pollution in this region. 2.1 Overview of the Study Area The study area, Qingdao is situated between 119°30'~121°00'E longitude and 35°35'~37°09'N latitude. Qingdao extends over a total area of10654 km2. Qingdao receives an average annual rainfall of 775.6 mm. Mountainous, plain regions, hilly region and lowland occupy the watershed the 15.5%, 37.7%, 25.1% and 21.7% of land area receptivity.
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2.2 Research Methods This research uses MUSLE equation, which improved on the basis of USLE (Universal Soil Loss Equation) developed by the United States Department of Agriculture (USDA)[18]. It will help to apply GIS to evaluate the non-point source pollution risk area. The expression is as follows:
P = K • S •W •U
(1)
In the formula (1): P is non-point source pollution risk, which expresses the risk of soil erosion and contaminants eluviations; K is the soil factor; S is the slope factor; W is the channel factor; U is the land-use factor. Compared to the original USLE and other non-point source pollution model, the risk map generated by MUSLE equation does not give the actual pollution load information, but it can be used to identify the high erosion risk or impact area to the surface water quality in the study area. MUSLE model can be based on normal commercial GIS platforms (such as ArcView and ArcGIS) to apply and analyze. It usually uses the grid data to compute and the model requires spatial data as input parameter, including DEM, land use maps, soil maps and water maps. The process is shown in Figure 1.
Fig. 1. The processing map of the non-point source pollution risk based on spatial information technology
2.3 Compute Using Model 2.3.1 Data Preparation This research requires some spatial data including DEM, land use map, soil map and river map. All input data are used Albers Equal-Area Conic projection. Due to land-use data is interpreted from the TM remote sensing image, which grid size is 30m × 30m, so other spatial data are all turned to the same size. USLE equation is recommended for small area and the grid size used in this study basically meets the need. (1) Soil map: the main soil classes in the study area are decided by the classification value given by McElroy et al [19], as shown in Table 1.
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Class Till Water Gravel Clay
Grid value 0.380 1.000 0.200 0.450
(2) Slope length map: in the ArcGIS 9.2, we load the Spatial Analyst module. The slope map is generated after filling depression for DEM and named slope, then we generate flow accumulation map in the Hydrology module. Before get slope length map, we must set the grid value of the rivers, lakes and other water bodies as 0 in order to avoid producing high values which do not meet the fact. The treated accumulation map is named Accumulation. Finally, run the following expression and get slope length map. Pow([Accumulation]*86.1794/22.1,0.6)*Pow(Sin([slope]*0.01745)/0.09,1.3)*1.6 (2) (3) Land use maps: the main land use classes in the study area are decided by the classification value given by McElroy et al [19], as shown in Table 2. Table 2. Land use class in the study area
Class Water Forest Pasture Urban Other open land Agriculture
Grid value 0.000 0.005 0.010 0.030 0.100 0.100
(4) River map: we apply the distance tool to calculate each grid distance from the nearest water bodies and then calculation on the resulting grid maps (named distance), the expression is: 0.6/(Exp(0.002*[distance])-0.4)
(3)
2.3.2 The Results In this study, the model calculation is based on ArcGIS 9.2 platform, the main application of the GIS includes conversion function between vector data and raster data, re-classification function, search distance function and grid data computing function. First of all, we convert all layers to 30m × 30m ESRI Grid format, then calculate in turn the slope length factor-S value (Figure 2), soil factor-K value (Figure 3), land-use factor-U value (Figure 4) and river factor-W value( Figure 5), which are the input parameters of the MUSLE model.
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Fig. 2. The map of slope length factor
Fig. 3. The map of soil factor
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Fig. 4. The map of land-use factor
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Fig. 5. The map of river factor
Then we run the ArcGIS 9.2 Spatial Analyst module to make the four factors mentioned above multiplicative and generate the non-point source pollution risk map. The values of the map range from 0.00 - 29.430. Finally, according to statistical rules, using the mean and 1 and 2 standard deviations, we make the result into four categories for statistical and mapping and get the non-point source pollution risk classification tables (Table 3) and distribution map (Figure 6).
Table 3. The non-point source pollution risk classification tables
Risk classification Safe region Low risk region Middle risk region High risk region
Grid value
Area proportion 0-0.005(below average) 69.08% 0.005-0.035(0-1 standard deviations above the mean) 18.42% 0.035-0.065(1-2 standard deviations above the mean) 4.38% 0.065-29.430(> 2 standard deviation) 8.11%
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Fig. 6. The non-point source pollution risk distribution map of the study area
3 Conclusion and Outlook This study describes the development process and the basic method of the study of the non-point source pollution and introduces the application of the spatial information technology in the non-point source pollution research. On this basis, we collect a variety of spatial data of the study area and use the MUSLE equation to divide the study area into safe region, low risk region, middle risk region and high risk region. The results show that the more serious regions of the non-point source pollution in the study area distribute in mountainous and hilly areas, where is steeper, has more developed river system and is prone to runoff, so these area has higher risk to bring non-point source pollution. In this study, we use the spatial model to study the non-point source pollution. It is showed that the spatial model requires few amount of data, saves time and labor, is simple and with full scientific. Although it can not calculate a specific non-point source pollution load, it gives the risk area of the non-point source pollution. So this study provide a strong basis to facilitate the non-point source pollution management and control for environmental managers and policy makers. We can see that the spatial information technology is a powerful tool to study the non-point source pollution and will be indispensable and play an important role in the future.
Acknowledgments Project supported by the Science and Technology Projects of Qingdao (09-1-1-53-nsh and 08-2-1-36- nsh).
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References [1] Wang, X.Y.: Theory and Methods of Quantitative Study on Non-Point Pollution. Journal of Capital Normal University (Natural Science Edition) 17, 91–95 (1996) [2] Vladimir, N., Gordon, C.: Handbook of Nonpoint Pollution Sources and Management, 1st edn. Van Nistrand Reubhold Company, New York (1981) [3] National Water Quality Inventory: Report to Congress Executive Summary, USEPA, Washington (1995) [4] Jin, X.C., Liu, S.K., Zhang, Z.S.: China Lake Environment, 1st edn. China Ocean Press, Beijing (1995) [5] Wang, X.Y.: Non-point source pollution and its management, 1st edn. China Ocean Press, Beijing (2003) [6] Wischmeier, W.H., Smith, D.D.: Predicting rainfall erosion losses. a guide to conservation planning. Agriculture Handbook No. 537, U.S. Department of Agriculture, USDA, Washington (1978) [7] Arnold, J.G., Allen, P.M., Bemhardt, G.A.: A comprehensive surface-groundwater flow model. Journal of Hydrology 14, 47–69 (1993) [8] Xia, Q.: Calculation of non-point source pollution load in the watershed mode. China Environmental Science 5, 23–30 (1985) [9] Shan, B.Q., Yin, C.Q., Bai, Y.: Study on phosphorus load from a watershed with rainfall simulation method. Acta Scientiae Circumstantiae 20, 33–37 (2000) [10] Cai, C.F., Ding, S.W., Shi, Z.H.: Prediction on soil nutrients losses at typical small wate rshed of three gorges area with gis. Journal Of Soil And Water Conservation 5, 9–12 (2001) [11] Bao, Q.S., Wang, H.D.: China’s non-point source pollution of water environment research and prospects. Scientia Geographica Sinica 16, 66–71 (1996) [12] Liu, F., Wang, H.D., Liu, P.T.: Watershed non-point source pollution identification and quantification in the Yuqiao Reservoir Basin. Acta Geographica Sinica, 329–339 (1988) [13] Liu, Y., Zhang, T.Z., Chen, J.I.: Discussion on charge policy for governance of agricultural non-point source pollution in dianchi watershed”. Journal of Xiamen University (Natural Science) 11, 787–790 (2003) [14] Pan, G.X., Jiao, S.J., Li, L.Q.: Effect of longterm fertilization practices on mobility of phosphorus in a huangnitu paddy soil receiving low P input in the Taihu lake region, Jiangsu province. Chinese Journal of Environmental Science 3, 91–95 (2003) [15] Yan, W.J., Bao, X.: Study on agricultural movement of Chaohu lake basin and non-point source pollution. Journal of Soil and Water Conservation 12, 128–132 (2001) [16] Wang, S.P., Yu, L.Z., Xu, S.Y.: Research of non-point sources pollution loading in suzhou creek. Research of Environmental Sciences 27, 20–23 (2002) [17] Zhen, Y., Wang, X.J.: Advances and prospects for nonpoint source pollution studies. Advances in Water Science 13, 105–110 (2002) [18] Sivertun, A., Reinelt, L.E., Castensson, R.: A GIS method to aid in non-point source critical area analysis. International Journal of Geographical Information Systems 2, 365–378 (1988) [19] McElroy, A.D., Chiu, S.Y., Negben, J.W.: Loading functions for assessment of water pollution from non-point sources, 1st edn. US Environmental Protection Agency, Washington, DC (1976)
The Regulation Analysis of Low-Carbon Orientation for China Land Use Bikai Gong and Bing Chen Institute of Land Reclamation and Ecological Restoration, China University of Mining and Technology (Beijing); Engineering Research Center of Mining Environment & Ecological Safety, Ministry of Education, 100083 Beijing, China [email protected]
Abstract. Greenhouse gas emission reduction has become the responsibility and consensus of all mankind’s development, the way of non-sustainable land use results in a lot of greenhouse gas emissions in the context of low-carbon economy. On the basis of revealing impact of land use on carbon emissions and status of carbon emissions, this paper proposes the regulation proposals of land use based on low-carbon emission: make carbon emission’s list of land use, optimize land use structure and layout, and strengthen land use control, intensive land use, soil and water conservation and ecological protection, management of agricultural land, woodland, grassland and wetland, control the scale of construction land and pace of expansion, establish compensation mechanism of land ecology. The research has great significance for China forming and further improving the policy system of land use of low-carbon emission. Keywords: land use; low-carbon economy; regulation; China.
1 Introduction “Our future energy – creating low-carbon economy” of the British Government in 2003 first proposed the concept of low-carbon economy, the core idea is to obtain more economic output with less energy consumption[1]. Then low-carbon economy attracted international attention, it advocates resource conservation, friendly environment and sustainable development, and reduces high-carbon energy consumption of coal, petroleum and others possibly, improve energy efficiency substantially, large-scale utilize renewable and low-carbon energy, large-scale develop emission reduction technology of greenhouse gas, build low-carbon society and maintain ecological balance. The development of low-carbon economy is global revolution involved in mode of production, lifestyle, values, national interests and human destiny, as well as an inevitable choice of the global economy being transferred from high-carbon energy into low-carbon energy[2, 3]. The development of low-carbon economy is not only a global effective way to climate warming, but also an inevitable choice of China saving energy, reducing emission and participating in international cooperation. China is in period of rapidly developing industrialization and urbanization, the coal –dominated energy structure D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 602–609, 2011. © IFIP International Federation for Information Processing 2011
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results in China’s emission of carbon dioxide in the forefront of the world. In 19992003, the emission of carbon dioxide increased by 170 million tons, and China has become the world’s second largest emission country[4]. On the research of lowcarbon economy, some China scholars proposed many useful ideas. Zhuang Guiyang showed that the essence of low-carbon economy is the problem of high-energy efficiency and clean energy structure, the core is the innovation of energy technology and system[5]. Zhang Kunmin analyzed the facing challenge of China developing low-carbon economy from the view of energy, and thought energy strategy of supporting sustainable economic and social development needs to be build[6, 7]. Xia Kunbao showed that low-carbon economy is the only way to achieve sustainable urban development; it needs to carry out mode of low-carbon production and consumption, and greatly develop circular economy and clean production[8]. Low-carbon economy seems to be the problem of environmental technology’s application and industrial structure’s optimization, but the problem of land use essentially. China has been concerned about impact of land use on global change for a long time, and proposed policy advice on the regulation of land use based on impact of land use on carbon emissions and status of carbon emissions. Conventional regulated policies of low-carbon, with the use of policies of land use structural optimization, and the introduction of regulated measures of land use, have a great significance of China performing and successfully achieving the promise of voluntary emission reduction.
2 Impact of Land Use on Carbon Emissions Glaeser and Kahn analyzed the relationship between carbon emissions and land use, and thought constrains on land use are more strict, carbon emissions’ level of the residents living are lower[9]. The change of land use is an important uncertainty factor in the estimates of carbon emission. On the one hand, the change of land use changes the types of ecosystem directly, and then changes the net primary productivity of ecosystem and their inputs of soil organic carbon; on the other hand, the change of land use changes soil physical and chemical properties potentially, and then changes soil respiration’s sensitivity coefficient to temperature changes. Land use plays an important role in increasing global atmospheric carbon dioxide, and China’s change of land use has great impacts on carbon emission of terrestrial ecosystem. The way of long-term non-sustainable land use (deforestation, reclamation of grassland, transformation of marshes, etc.) results in the release of carbon from terrestrial ecosystem, and becomes one of the main reason of atmospheric carbon dioxide rising, only second to fossil fuel burning. According to the calculations of the World Resource Organization and well-known experts on the carbon cycle, in the global carbon emissions from 1850 to 1998, land use change and its carbon emissions accounted for 1/3 of the total emissions of human activities affect; while the cumulative carbon emissions of the whole country’s land use change were 10.6PgC from 1950 to 2005, accounting for 30% of the total artificial carbon source emissions, as well as 12% of carbon emissions of global land use change at the same period[10]. There are direct and indirect carbon emissions from the classification of carbon emissions of land use. Direct carbon emissions can also be subdivided into carbon
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emissions of changed and maintained land use types. The former refers that the change of land use or cover type results in carbon emissions caused by the change of ecosystem type, such as deforestation, reclaiming land from lakes, construction land expansion and so on; the latter refers to carbon emissions driven by the change of land management and carbon sink of ecosystem, including farming, grassland degradation, nutrient input and changes of cropping systems. Indirect carbon emissions mainly refer to all man-made carbon source emissions carried on each type of land use, including the heating of neighborhood, exhaust from traffic land, and process emissions of mining land; they are spatial intensities and distributive effects of artificial carbon source emissions on the different land use types.
3 The Status of Carbon Emission Reduction of Land Use In 2006, China’s disposable energy consumption accounted for more than 16% of the world, and the emissions of carbon dioxide were more than 20% of the world, equal with per capita emissions in the world. This indicated that, in the process of industrialization and urbanization, the intensity of carbon emissions is a little high, while energy consumption will continue to grow, with not much room for carbon emissions. Describe the statue of carbon emissions of China’s land use based on direct and indirect carbon emissions of land use, carbon emissions effect of land use types, and regional carbon emissions. 3.1 Direct Carbon Emissions of Land Use From 1980 to 2005, terrestrial ecosystem has presented obvious carbon sinks, and the average annual level of carbon sinks were about 154 to 167 million tons of carbon. From the view of classification structure, vegetation and soil carbon pools both presented the functions of carbon sinks, the average annual carbon sinks of vegetation was 108 to 121 million tons, and the capacity of soil carbon sinks was weak with 1/3 of vegetation carbon sinks. From the view of ecosystem types, the function of forest carbon sinks had the obvious effect on the whole terrestrial ecosystem, about 2/3 of the whole terrestrial ecosystem. From the view of spatial pattern, the carbon sinks of land use had more significant effect in east, south and north China, and there was more significant effect of carbon emissions of land use in northeast and southwest China, while there was less effect in northwest China. 3.2 Indirect Carbon Emissions of Land Use Take the comprehensive level of carbon emissions of China’s four departments in 1995 for an example, the total emissions of carbon dioxide were 2.642 billion tons, methane was 32 million tons, and the carbon dioxide equivalent was about 3.3 billion tons. In 2005, the total emissions of carbon dioxide were 5.55 billion tons, methane was 38 million tons, and the carbon dioxide equivalent was about 6.34 billion tons. In the 80th of last century, artificial source emissions were as 3 times as the storage of terrestrial ecosystem, but 10 times in 2005. Therefore, the increase of artificial resource carbon emissions was much faster than the promotion of carbon’s absorptive capability of terrestrial ecosystem[10].
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3.3 Carbon Emission Effect of Land Use Types Without considering the situation of carbon’s absorption, the general carbon emission intensity of agricultural land is 0.37 tons per hectare, below the international average level. The main reason is that China traditional agriculture paid attention to the use of organic fertilizer and straw, so the effect of organic carbon storage of agricultural soil was remarkable. Forest is an important carbon sink, the carbon emission intensity is 0.06 tons per hectare and the carbon absorption intensity is 0.49 tons per hectare. Since the 70th or 80th of last century, the strong advocating of afforestation has resulted in forest volume rising, large young forest had obvious carbon absorption effect of growth, stronger than at the same period of timber harvesting, firewood collection, disaster interference and other effects. For construction land, there were the highest volume and intensity of carbon emissions. The emission intensity of construction land was 55.8 tons per hectare in all. That means that there will be 149.8 times of carbon emission when transforming one hectare of agricultural land into construction land; while transforming one hectare of forest land into construction land, it will increase 929 times of carbon emissions. From the view of different regions, there were the highest carbon emission intensity of construction land in north and east China, about 81.2 tons per hectare and 65.3 tons per hectare; the general level in northeast, middle south and southwest China, about 48.8 tons per hectare, 46.5 tons per hectare and 49.1 tons per hectare; lower level in northwest China about 33.9 tons per hectare. In a word, there are greater carbon emissions of per unit area of construction land in areas of high levels of heavy industrialization and big population density. From the view of the internal structure of construction land, there was highest carbon emission intensity in industrial and mining land, about 196 tons per hectare; followed by traffic land, about 43.7 tons per hectare; the smallest was urban and rural residential land, only about 8.3 tons per hectare[10]. 3.4 Carbon Emissions of Regional Land Use As the world’s major energy consumer, China’s carbon emissions are not only reflected on volume’s growth, but also spatial pattern change of carbon emissions. From the view of the change of large regional system, the carbon emissions in the east have dominated the country all the time; the proportion of central region’s carbon emissions in the country showed the trend of flatting to down; and the proportion in the western region was small but basically maintained an upward trend[11]. Specifically as follows: there were high carbon emissions in most regions of east and north China, as well as Pearl River Delta, Yangtze River Delta, middle-south cities of northeast China and Chengdu-Chongqing Urban Agglomeration. There were lowcarbon emissions or carbon balances in northwest China and most of Qinghai-Tibet Plateau. While the main areas of carbon sinks were in most of southwest, middlesouth, southeast China, part of northeast China, and Tianshan-Qingling zones. Besides, the afforestation areas in north and part of northwest China had a positive effect of carbon sinks.
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4 The Regulated Suggestions of Land Use on the Basis of Low-Carbon As the world’s largest developing country, China’s economic development rely on resources consumption of fossil energy greatly, that resulted in increased carbon emissions and heave environmental pollution, these issues have seriously affected the quality of economic growth and the sustainability of development. The economic and social development drove China’s carbon emissions, but the policy of increasing sinks such as commonly ecological protection and afforestation had no significant influence on containing carbon emissions increase. While the potential of carbon emission reduction after the optimization of land use structure in low-carbon economic development and macro-control is 1/3 of conventional low-carbon policy. China has been highly concerned about energy conservation and land use on the impact of global change, on the basis of revealing the effect mechanism of carbon emissions of land use, form land use structure and layout of low-carbon emissions though innovating techniques of land use planning. That had great significance for further improving the policies of carbon emission reduction, particularly forming China’s policy system of land use of low-carbon emissions. 4.1 Make the List of Carbon Emissions of Land Use At present, home and abroad related standard of calculating carbon emissions are mainly on the basis of “2006IPCC Guidelines for National Greenhouse gas inventories”, and “Initial National Communication on Climate Change” based on the domestic status in 1994, recently the new “Second Communications on Climate Change” has not yet to be introduced. The above files or standards have been difficult to meet the actual demand of the land department making decision, so carbon emission analysis of land use fitting the situations need to be made according to China’s unique classification system of land use, vegetation and soil. Overall China natural and social-economic carbon emissions of land use for nearly 20years, form carbon emission lists of fitting land use and its vegetation characteristics, on line with the current classification system of land use, and develop appropriate standards, in order to provide theoretical basis for macroscopic policymaking department to carry out low-carbon land use plan. 4.2 Establish Matchable System of Low-Carbon Land Use Policy Currently, developing low-carbon economy and taking the road of low-carbon ecology is an inevitable direction of transforming in many cities, especially resourcebased cities. In order to change the way of low-carbon land use and set up awareness of low-carbon land, China also needs to propose fitting matchable system of land use policy based on low carbon from two views of carbon emission reduction and increased carbon sinks. The policy of increased carbon sinks includes optimization of land use structure, water and soil conservation, ecological protection, and the management of forestland, farmland, grassland and wetland; the policy of carbon emission reduction includes optimization of land use structure, carbon emission reduction of agricultural land and construction land, mechanism’s construction of land ecological compensation and others.
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(1) Optimize the structure and layout of land use From the view of emission reduction of increased carbon sinks of various land management policy, there are greatest potential for carbon emission reduction of land use structure’s optimization. Innovating planning techniques of land use can further optimize the structure and layout of land use. Restricting non-sustainable way of land use, increasing the scale of forest area, controlling the reduction of cultivated land, grassland, marsh, beach and the expansion of construction land, and promoting the transformation from unused land into woodland, grassland and cultivated land, will produce more positive effects for carbon storage of China ecosystem. (2) Strengthen land use control China has been in period of rapid development of industrialization and urbanization, large scale infrastructure construction should be carried out by the way of low power, high efficiency and low-carbon emissions. Many cities are in the time of rapidly expanding, necessary controls and regulations need to be carried out for development of urban traffic and urban land at the same time[12]. Use urban dynamic emulation analysis, and fully stimulate traffic distance and carbon emissions of different granting schemes in the supply of urban land, in order to achieve balanced distributions of all kinds of land in the urban and scientifically plan to reduce urban carbon emissions. Besides, promote industrial low-carbon by the policy of supplying land. Through land participating in macro-control, strengthen land review, strictly control blind expansion of “three high” industries (high intensity of energy consumption, high carbon emissions, high pollution), and encourage the development of low-carbon industry. When increasing approvals of construction land, local government will give priority to protect industrial land of low-carbon economy, contain project sites of excess capacity and duplicate construction. Build cyclic economic parks and lowcarbon developed test areas of land use. Accelerate establishing demonstration industrial parks, industrial parks and economic development parks of energy-saving low-carbon. Overall urban and rural construction with the idea of low-carbon economy, and develop new characteristic industrialization and urbanization fitting local realities. (3) Strengthen the saving of intensive land use Strengthen the saving of intensive land use, reduce emission of architectures. The saving of intensive land use not only reduces the consumption of land resources directly, but also produces more advanced architecture models, more efficient operated ways and more scientific streaming configurations though being replaced by more abundant elements. These will reduce the output of energy consumption and carbon emission per unit. (4) Strengthen water and soil conservation and ecological protection In important areas, sensitive areas and ecologically fragile areas of affecting the national ecological security, strictly control land desertification and water and soil erosion, and strengthen water and soil conservation and ecological protection; in the desert and Gobi areas, speed up the greening process of land and afforestation, newly increase areas of planting forest and forest carbon sinks.
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(5) Strengthen management of agricultural land Develop new agriculture of organic, ecology, and efficiency; reduce the use of chemical fertilizers and pesticides. The potential for carbon emission reduction of agricultural land’s management can not be ignored. According to the study, the carbon sequestration capacity of agricultural soil has increased 0.014%per year in the last few years with the improvement of the quality of cultivated land. Deeply study the carbon sequestration of farmland ecosystem, mitigate climate changes through biological and ecological carbon sequestration. Optimize farming system, promote the use of organic fertilizers, and improve the content of organic matter in soil. Straw returning to field increase soil nutrients and reduce soil erosion by wind and water. With materials of livestock manure, crop straw and other agricultural organic wastes, relying on the technology of recycling economy, achieve the exchange of each agricultural by-products and recycling use of wastes, and turn organic wastes into resources. (6) Strengthen management of forestland, grassland and wetland The studies show that, forest vegetation is the most effective carbon sink in the earth, the annual net carbon uptake of the global average per hectare of forest vegetation is about 0.26~0.39t. Developing forestry is an important measure to develop low-carbon economy, plant trees and grasses, strengthen management of wetland, and expand carbon sinks. Since the 80s of the 20th century, due to the large scale of afforestation and returning farmland to forest, animal husbandry, and lakes, the level of carbon storage in terrestrial ecosystems has improved significantly, 1/4~1/3 of artificial carbon emissions at the same period were absorbed[10]. Deeply study the carbon sequestration of grassland and forest ecosystem, mitigate climate changes through biological and ecological sequestration. Since 1949, there have been great achievement of afforestation, but the existing level of forest’s maintenance and management should be improved, in order to reach the maximize of making oxygen from forest. For the main content of afforestation, speed up the construction of ecological barriers, continue to promote the construction of shelterbelts of upper and middle yangtze river and three-north area, increase forest coverage, and improve territory virescence. (7) Control the scale of construction land and the speed of expansion The requirements of coordinating urbanization and low-carbon are defining the scale of construction land, spatial scope and expanded pace of the overall urban planning in the level of urban planning. And the space of construction land are divided through the analysis of eco-environment capacity and development space in the level of urban planning, including the balanced mold of the whole shape of low-carbon, dynamic balance of low-carbon land use, green system’s design of low-carbon road and others[13]. (8) Establish the mechanism of land ecological compensation The total values of land resources include not only economic value, but also ecological value and social value[14]. Land ecological compensation includes that the state could expropriate tax of environmental resources, in order to ensure the government provide public service functions of ecological products of land resources. Besides, people who suffers the loss or pays the economic costs because of public
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interests (ecological protection) should be given fair compensation. Through accurately measuring and calculating areas of land for different use, combining with other empirical data, ecological value formed by the status of land use can be calculated.
References 1. Zhang, Q., Ye, X.-p., Chen, G.-w.: Low-carbon urban planning:a new vision. City Planning Review 34(2), 13–18 (2010) 2. Zhang, G.-f., Liu, Q.-w.: A study on low carbon economy policy based on equity theory. China Coal 36(1), 6–8, 12 (2010) 3. Huang, W.-s.: On the low-carbon tourism and the creation of low carbon tourist attractions. Ecological Economy (11), 100–102 (2009) 4. The carbon emission report of world-bank[EB/OL], http://i.cn.yahoo.com/billasx/blog/p22/ 5. Zhuang, G.-y.: The way and potential of China’s low-carbon economy development. Studies in International Technology and Economy 8(3), 8–12 (2005) 6. Zhang, K.-m.: China’s role,challenges and strategy for the low carbon world. China Population Resources and Environment 18(3), 1–7 (2008) 7. Zhang, K.-m.: Development of low-carbon economy is China’s internal demand. Theoretical Horizon (2), 26–28 (2010) 8. Xia, K.-b.: Development of low-carbon economy,urban sustainable development. Environmental Protection (3), 33–35 (2008) 9. Glaeser Edward, L., Kahn Matthew, E.: The greenness of cities:carbon dioxide emissions and urban development. Journal of Urban Economics 67(3), 404–418 (2010) 10. Carbon emissions: issues of land use regulation and control[EB/OL] (December 25, 2009), http://www.mlr.gov.cn/tdsc/lltt/200912/t20091228_131048.htm 11. Lei, Z., Huang, Y.-x., Li, Y.-m., et al.: An investigation on spatial changing pattern of co2 emissions in China. Resources Science 32(2), 211–217 (2010) 12. Pan, H.-x.: Urban spatial structure towards low carbon:new urban transport and land use model. Urban Studies 17(1), 40–45 (2010) 13. Han, Q., Liu, H.-l.: Low-carbon eco-towns planning and research. Development of Small Cities & Towns (12), 73–78 (2009) 14. Gong, B., Deng, L., Hu, Y., et al.: Study on ecosystem service and its value assessment of cultivated land of reservoir inundated—a case study of Huangjinping hydropower station. Resource Development & Market 23(12), 1085–1088 (2007)
A CDMA-Based Soil-Quality Monitoring System for Mineland Reclamation Dongxian He1, Daoliang Li2, Jie Bao3, and Shaokun Lu1 1 Key Lab. of Agriculture Engineering in Structure and Environment, College of Water Conservation and Civil Engineering, China Agricultural University, Beijing, P.R. China 2 College of Information & Electrical Engineering, China Agricultural University, Beijing, P.R. China 3 College of Engineering, China Agricultural University, Beijing, P.R. China [email protected]
Abstract. After the mining of mineral resource, mineland resources utilization became increasingly complicated. Soil and planting information can be used as the indicators to evaluate mineland reclamation level. In order to obtain the soil and planting information in real time, a CDMA-based soil-quality monitoring system was developed to wirelessly monitor air/soil environment and plant image in remote or local area. As a system test, a monitoring system equipping one network camera and four sensors including air temperature, relative humidity, soil temperature, and soil water content was deployed at a national mineland reclamation demonstration in Fuxin, Liaoning and communicated with a remote server in Beijing using CDMA service with IPsec-based VPN connection. Via a one-year testing, the CDMA-based soil-quality monitoring system as a dynamic infrastructure and available tool showed a good performance for mineland reclamation quality evaluate. Keywords: CDMA service, Mineland reclamation quality evaluate, Soil water content, VPN connection.
1 Introduction After the mining of mineral resource, mineland resources utilization became increasingly complicated. In order to obtain the mineland detail information in real time for the reclamation in land administrative department of mining enterprise concerned, soil and planting information changes of mineland area is very important and can be used as the indicators to evaluate mineland reclamation level. How to get the indicator information and how to sign the reclamation quality is concerned to sustainable development of mineland reclamation utilization. Therefore, efficiency and low cost way to get mineland reclamation quality change is essential and required for mining enterprise and land administrative department. Mining land reclamation by the quality indicator technology developed in recent decade is based on wireless network technology, GIS, and remote sensing technology D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 610–615, 2011. © IFIP International Federation for Information Processing 2011
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can be used as the integration charge of indicators of reclamation quality index. In the past 10 years, mineland reclamation in the quality indicator technology has carried out a significant development and has achieved remarkable achievements [1-8]. Therefore, development of a dynamic monitoring system of mineland reclamation for obtaining the soil and planting information in an efficiency and low cost way is becoming required and becoming more important.
2 Materials and Method 2.1 System Configuration The CDMA-based soil-quality monitoring system consists of a CDMA module with IPsec-based VPN function (InRouter210C, Beijing Inhand Co., China), a network bullet camera (IP7330, Vivotek Co., Taiwan), a web-server-embedded chip (PICNIC2.0, TriState Co., Japan), switching hub (TL-SF1005D, TP-Link Tech. Co., China), a sensor module, and a solar power supply module (SPV-DCRC-20W, Beijing Sangpu Co., China) (Fig. 1). The sensor module is including temperature (PT1000, Hayashi Elect. Co., Japan), relative humidity (CHS-UPS, TDK Co., Japan), soil temperature (PT1000, Hayashi Elect. Co., Japan) and soil water content (EC-5, Decagon Co., US). The power supply module consists of a power control device, two 20W monocrystalline silicon photovoltaic panels, a 75AH battery (LC-X1275ST 75AH, Panasonic Co. Japan), and a timer (ZN48T-12V, Symore Co. China). The realtime data and images collected by the sensors and network camera are dynamically and wirelessly transported to a remote server via TCP/IP. The CDMA-based soilquality monitoring system was operated between appointed duration by a timer.
Fig. 1. The CDMA-based soil-quality monitoring system
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2.2 Topological Architecture Each CDMA-based soil-quality monitoring system as an isolated local area network is connected to Internet via CDMA service by Telecom China (Fig. 1). That means the monitoring system as a sensing network node can be constructed to a large-scale wireless sensing network under CDMA signal covered areas. The monitoring system is also easy to increase sensor channels and network cameras as well as the CDMA bandwidth depending. In this monitoring system, four sensor channels were integrated into the webserver-embedded chip within one LAN IP and each camera has a LAN IP. All data and images are communicated by dynamic HTTP file and identified dynamically and storied by one to five remote servers. The CDMA module will be dynamically connected to the remote servers via IPsec-based VPN security technology. In order to identify the specified the remote servers, the remote VPN routers have to use a dynamic domain connection or a fixed global IP to support the remote VPN calling. The monitoring systems deployed anywhere will become to a local network connection because of the IPsec-based VPN tunnels connected. Therefore, all accredited users or clients can visit or manage the wireless sensing devices anywhere and anytime under Internet environment. 2.3 Testing Environment A CDMA-based soil-quality monitoring system was deployed in a national mineland reclamation demonstration zones in Fuxin, Liaoning province for obtaining air and soil environment, and plant images. In this testing, one remote server with IPsec-based VPN router (BV-601, Nesco Co., China) is deployed in China Agricultural University located in Beijing, China. The testing experiments were conducted for one year.
3 Results and Discussion 3.1 Dynamic Image Transportation A Java applet program was installed in the remote server to download image from the network camera via HTTP every minute and stored in the remote server. In order to monitor more areas, the network camera has setup in two benchmark level for measuring height of plants and leaf area index (Fig. 2). The image processing results
Fig. 2. The dynamic images obtained by the CDMA-based soil-quality monitoring system
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will be described by other papers and omitted in this paper. All accredited users can visit or manage the network camera modules and any clients can visit the real-time or historical images from website anywhere and anytime under Internet environment. Therefore, this network camera module with an enough-quality dynamic image requirement at low cost is suitable to the monitoring system. 3.2 Dynamic Environment Data Transportation The environmental data such as temperature, relative humidity, soil temperature, and soil water content were dynamically storied or issued in webpage or Extensible Markup Language (XML) file by a special JAVA applet program in the remote servers (Fig. 3). The 10-bit analog signals of the sensors were obtained by the webserver-embedded chip without any memory and firmware. Therefore, the legacy problem of the USB-based or RS232-based devices caused from the firmware update can be solved in this monitoring system. The environmental data were also used to combine with image processing results such as the shape and color features to construct an artificial neural network model based on back-propagation algorism for identifying the growth measurement and nutrition detection. The sensor module is easy to increase the sensor channels with a little influence in data communication, because the narrow CDMA bandwidth will strongly influence the image communication in this monitoring system.
Fig. 3. Environmental data measured by the CDMA-based soil-quality monitoring system
3.3 Network Communication and Electronic Consumption The monitoring system were communicated with the remote server in Beijing by a 20-30 Kbps access speed with over 25-27 signal quality level of CDMA services. The real-time image with 640*480 pixels resolution captured by the network camera and
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compressed to JPEG file were dynamically transported to remote server during the system operation. The all data and images obtained at same time were identified by IP which is transferred to take turns and with omitted disconnecting IP. In this case, less than 2% of packet loss rate was resulted. Local user can visit the remote server via LAN, remote users can visit the remote server through Internet. These two methods have nothing to do with the CDMA. Therefore, remote user access speed is limited by the bandwidth of Internet hotspot such as ADSL network in this case. The remote server can support simultaneous accesses of 20 remote users. However, the numbers of concurrent local users do not have measurements and no restrictions on. The monitoring system using 12V DC power supply and timed operation by solar supply system consisting of two 20W solar panels and a 75Ah battery were consumed about 22W capacity with 1.8A electric current. This power supply module can drive the monitoring system for about 10 hours in sunshine day and for about 5 hours in cloudy day. Therefore, four hours operation divided to two hours in morning or afternoon were connected in this system testing.
4 Conclusion The real-time environment data and images were dynamically collected in remote area by the CDMA-based soil-quality monitoring system. This CDMA-based soilquality monitoring system based on web-server-embedded technology and CDMA service with IPsec-based VPN function as a node infrastructure is useful to construct a ubiquitous wireless sensing network in high-security for mineland reclamation.
Acknowledgments This work has been supported by International Technology Cooperation Program (2007DFA91050).
References 1. Bradshaw, A.: The use of natural processes in reclamation — advantages and difficulties. Lands. Urb. Plan. 51, 89–100 (2000) 2. He, D.X., Hirafuji, M., Fukastu, H., Yang, Q.: An environmental measurement system using wireless networks and web-server-embedded technology. In: Progress of Information Technology in Agriculture, pp. 541–545. China Agriculture Press, Beijing (2003) 3. Chena, J.C., Changb, N.B., Shieh, W.K.: Assessing wastewater reclamation potential by neural network model. Eng. Appl. Artif. Intell. 16, 149–157 (2003) 4. Fukatsu, T., Hirafuji, M.: Field monitoring using sensor-nodes with a web server. J. Robot. Mechatron. 17, 164–172 (2005) 5. Sevkiye, S.T.: An analysis on the efficient applicability of the land readjustment (LR) method in Turkey. Habitat. Int. 31, 53–64 (2007)
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6. Anderson, J.D., Ingram, L.J., Stahl, P.D.: Influence of reclamation management practices on microbial biomass carbon and soil organic carbon accumulation in semiarid mined lands of Wyoming. Appl. Soil Ecol. 40, 387–397 (2008) 7. Philip, A.T., Helmers, D.P., Kingdon, C.C., McNeil, B.E., de Beurs, K.M., Eshleman, K.N.: Changes in the extent of surface mining and reclamation in the central appalachians detected using a 1976-2006 Landsat time series. Remote Sens. Environ. 113, 62–72 (2009) 8. Li, F.H., Keren, R.: Calcareous sodic soil reclamation as affected by corn stalk application and incubation: a laboratory study. Soil Sci. Soc. Chin. 19, 465–475 (2009)
Design and Implementation of a Low-Power ZigBee Wireless Temperature Humidity Sensor Network Shuipeng Gong1, Changli Zhang1,2, Lili Ma1, Junlong Fang1, and Shuwen Wang1 1
Northeast Agricultural University, Harbin, Heilongjiang Province, P.R. China, 150030, [email protected] 2 Northeast Agricultural University, Harbin, Heilongjiang Province, P.R. China, 150030, Tel.: +86-451-55190456, [email protected]
Abstract. The key technology of greenhouse facilities is the monitoring of environmental parameters. Now, monitoring system of greenhouse is based on wire transmission. It is complicated to route wire and difficult to maintain. Also its reliability and anti-interference performance will degrade because of heat, light and acid. This paper leads a low-power and short range ZigBee technique into greenhouse monitoring system. In order to compose intelligent network sensor system, the paper analyses the composition of network nodes power consumption, proposes low-power design method both in hardware and software. The paper selects CC2430 module which composed of transceiver and microprocessor, and use SHT15 temperature humidity sensor. After hardware and software debugging, this wireless network can acquire and transmit data of greenhouse temperature and humidity accurately and rapidly, and this system resistant to stable work, tight structure, large loads and low power consumption. Keywords: Greenhouse, CC2430, ZigBee, Low-power, Temperature humidity sensor, Wireless network.
1 Introduction Now, monitoring system of greenhouse is based on wire transmission. It is complicated to route wire and difficult to maintain. Also its reliability and antiinterference performance will degrade because of heat, light and acid. As wire transmission brings many disadvantages, more and more monitoring systems use wireless sensor networks. ZigBee plays an important role in wireless sensor networks. ZigBee as a priority in wireless sensor networks because its advantages, such as low power consumption, high tolerance, Ad Hoc Networks [1]. In normal ZigBee network nodes use portable power (battery). Its harsh environment and large quantities make it very difficult to replace. So reducing the power consumption and extending the reliable working hours of sensor nodes become one of the key considerations. To compose intelligent sensor network system, the paper analyzes the consumption of the network and proposed low-power consumption methods both form hardware and software. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 616–622, 2011. © IFIP International Federation for Information Processing 2011
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2 System Design The system uses a tree topology and consists of coordinator, router and terminal node. Each router and terminal node carries temperature humidity sensor. The coordinator connects PC by RS-232 serial ports. It collects all nodes’ information and sends them to PC so that the manager can monitor and manage the information. Figure 3 shows the framework of the monitor system.
Fig. 1. The system uses a tree topology. This shows the framework diagram of the monitor system.
3 Low-Power Hardware Designs The hardware of the entire network includes coordinator and sensor nodes. Coordinator is powered by USB as coordinator connects with PC. So the low power strategy of the system mainly use in ZigBee nodes. ZigBee nodes are composed of processor module, wireless communication module, temperature humidity sensor module and power module. Figure 2 shows the structure of node.
Fig. 2. The node is composed of CC2430, SHT15 and power modules
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3.1 Processor Module Microprocessor is the central processing unit of the node. As the data that the microprocessor handled is large, the microprocessor is one of the most energy consuming components of the node. In the low power design, the microprocessor that the node used should be low power consumption and support sleep mode. As wireless communication account for most of the power consumption, the selection of the wireless module is very important. The following advantages of CC2430 make it become the ideal solution to solve the problem. CC2430 SoC integrates the CC2420 RF transceiver and enhanced 8051MCU. Its current consumption is 0.9uA on sleep mode and can be waked up by external interrupt or RTC wake-up system. Its current consumption is 0.6uA on dormancy mode and can be waked up by external interrupt. CCC2430 requires a large voltage supply between 2.0V and 3.6V [2]. 3.2 Sensor Module Sensor module uses temperature humidity sensor module SHT15. SHT15 integrates temperature humidity sensor, the conditioning and amplifying, A/D converting and I2C bus in one chip. The serial interface of SHT15 has a definite advantage both on the reading of sensor signor and power consumption. Current consumption is 550uA in measuring, 28uA in average, 3uA during sleep.
Fig. 3. This circuit diagram shows the interface of SHT15 and CC2430
3.3 Power Module Power module is mainly for CC2430 and SHT15. Voltage range of CC2430 is 2.03.6V; the SHT15 is 2.4-5.5V.The power of the system uses 2 #5 battery (3V), we can get 3.3V for the system after using DC-DC L6920 step-up chip. The following advantages make L6920 become the best choice: output voltage is 3.3V or 5V, even when the input voltage as low as 0.7V the system still can work (This can make sure that after a period of time of battery usage and the input voltage is falling the output voltage is still 3.3V ). This can enhance the stability of the system. The power consumption of L6920 is low. The working current is 18uA and only 5uA on sleep mode. Figure 4 shows Power circuit.
Low-Power ZigBee Wireless Temperature Humidity Sensor Network
619
L1 VIN
LX 10uH SHDN LBI
47uF
C3 REF GND
7
8
5
1
2
3
4
6
VCC
OUT FB C2 LBO 10uF
C1 47pF
GND
L6920
GND
Fig. 4. Power circuit diagram shows that the 3.3V battery
3.4 Processing of Spare Pins The system uses the CMOS chips. The charges cumulated by spare pins make the potential between “0” and “1”. The current complementary consist of an enhanced NMOS and an enhanced PMOS, the jumping of the potential from “0” to “1” or “1” to “0” will make the two pins instant short [3]. The intermittent short will bring short consumption. So connecting spare pins to the ground can reduce power consumption.
4 Low-Power Consumption of Software With the integrated circuit technological progress, power consumption of processor module and sensor module become very low. Figure 5 can explain the sensor node energy consumption, most of the energy consumption on wireless communication module; communication module has four states: transmitting, receiving, leisure and sleep, and energy consumption on transmitting, receiving and idle state is large, but the energy consumption on sleeping state is small [4]. So how to reduce power consumption on wireless communication has become an important problem.
Fig. 5. This shows all the consumption of sensor node
4.1 Working Mode of CC2430 In general CC2430 has low power consumption, it offers four power modes to choose: PM0/ PM1 /PM2/ PM3.
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CC2430 works on full-function PM0 mode, the frequency is 32MHz and 32.768 kHz, and the power consumption is less than 1mW. When it works on sleep mode PM1/PM2, Only the 32.768 kHz low-speed crystal run, the power consumption is less than 0.9uA, when it works on Hibernate mode PM3, there is no crystal run, so the power consumption is less than 0.6uA. After sending information, the node will be run into PM2-sleep mode. Because in this mode, it can run into full-function mode through internal sleep clock wake-up, and it does not require manual operation to wake-up. When the system works on SET_POWER_MODE (2) mode, sleep time can be set. the frequency of PM2 mode is 32.768kHz,timer of sleep is a 24-bit counter, so the longest sleep time of system is: T=2*24/32768=512s,the shortest sleep time is: T=1/32768 and it is about 30.5us. The setting function of sleep time is Set_ST_Period (uint16 sec), where sec is set according to user needs. 4.2 Low-Power Software Design The system wakes up nodes at regular time. Temperature and humidity is a gradual process, so it is no need to monitor it all the time. Monitoring it at regular time not only can monitor the change of temp and humidity, but also can reduce the working time of nodes. it is not necessary for the sensor nodes to communicate with coordinator all the time, this can avoid data collision and can reduce the power consumption.
Fig. 6. This shows the flow chart of software design and the sleep mode of CC2430
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After the establishment of ZigBee networks all sensor nodes send temp and humidity information to the coordinator. After receiving the confirmed information of coordinator the node gets into sleep mode. The coordinator connects to PC through RS-232 serial port. The temp and humidity information will display in upper machine. When the wake-up time arrives, the node will rouse from sleep and continue sending messages to coordinator. This method can make all nodes in sleep state in most of the time, which will significantly reduce the power consumption of the entire network. Figure 6 shows the flow chart of software design.
5 Implement of ZigBee Sensor Network The system uses a tree topology. The advantages of tree topology are as follows: it can extend transmission distance between coordinator and sensor nodes advance the ability to carry the load and enhance the area of the network.
Fig. 7. This shows the results that the PC collects. The information is temperature and humidity of greenhouse.
The connection of ZigBee coordinator and sensor nodes is bonding. Bonding is a mechanism from one application layer to another [5]. 2, 7, 8 are the labels of source nodes in the network, which can be determined when the program is downloaded. Each network ID is the only one in the network and each network ID correspond one sensor node [6]. We can monitor the temperature and humidity of the greenhouse through network ID. The power consumption of the nodes is 32.5mA in average.
6 Conclusion ZigBee wireless sensor network overcome many shortcomings that wired media bring in. This paper implements a ZigBee wireless sensor network that can transmit and
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monitor temperature and humidity of the greenhouse. This wireless sensor network resistant to stable work, tight structure, large loads and low power consumption. After low-power design, the power consumption of the network reduces, the effective working time of the sensor nodes extend and the stability of the system enhance. Each node can carry many sensors and controlled equipment, so the node can be added more sensor such as light sensor and CO2 sensor to collect more information of greenhouse. This ZigBee wireless sensor network is part of Internet of Things, and can be used in precision agriculture and industry and many other fields. Acknowledgments. Funding for this research was provided by Harbin Special Funds for Research on Technological Innovation Projects (NO.2008RFXXN003).
References 1. Bogena, H.R., Huisman, J.A., OberdÊrster, C., et al.: Evaluation of a low cost soil water content sensor for wireless network applications. Journal of Hydrology, 32–42 (2007) 2. Zhang, X., Zhang, C., Fang, J.: Smart Sensor Nodes for Wireless Soil Temperature Monitoring Systems in Precision Agriculture, pp. 237–240 (2009) 3. Li, W., Duan, C.: ZigBee2007/PRO experiment and practice of stack. Press of Beihang University, Beijing (2007) 4. Gao, J.: Study of energy consumption of ZigBee wireless sensor network node. Electronic Test, 1–4 (2008) 5. Sun, Y., Liu, Z.C., Cai, C.: Design of Low-power wireless sensor networks nodes. Computer Applications, 21–26 (2009) 6. Li, J., Zhang, C., Fang, J.: Design On The Monitoring System Of Physical Characteristics Of Dairy Cattle Based On Zigbee Technology. In: IEEE Proceedings of the 2009 International Conference on Computer and Computing Technology Applications in Agriculture (2010)
Land Evaluation Supported by MDS* Fengchang Xue School of Remote Sensing, Nanjing University of Information Science & Technology, Nanjing, Jiang Su Province, China. 210044 [email protected]
Abstract. GIS-MCE is the main method in land evaluation,but it is a linear method and neglects multidimensional complexity of factors used in land evaluation, which leads to information loss. Multidimensional scaling (MDS) originates from psychoanalysis, which is used to describe multidimensional data in higher dimensions by transforming data in higher dimensions into geometry structure in Lower dimensions. In the Land evaluation model supported by MDS, the data is transformed into a similar space and land evaluation is completed according to the spatial clustering based on the data’s spatial similarity ,which is a method drived by data and not dependenting on others priori assumption. Taking expropriation division in Xuzhou city as an example, it shows that the land evaluation based on MDS meets the requirements of land classification. Keywords: Land Evaluation, MDS Spatial Cluster model.
1 Introduction Land evaluation involves factors of soil, climate, vegetation, topographic and hydrology, which is an analysis integrating spatial information. In analysis of integrating spatial information, spatial data of different types and different sources can be taken as attribute of spatial cells, which have different spatial resolution and different spatial scale. So land evaluation can be taken as integrating spatial information of different sources and different spatial scales in specific information space. GIS-MCE is the main method in land evaluation, but it is a linear method and neglects Multidimensional complexity of factors used in land evaluation, which leads to information loss. Multidimensional scaling(MDS) originated from psychoanalysis, and it is used to describe multidimensional data in higher dimensions by transforming data of higher dimensions into geometry structure in Lower Dimensions. Based on this,Land evaluation supported by MDS is a method drived by data and not dependenting on others priori assumption. *
Foundation: Science and Technology support project of Nanjing University of Information Science and Technology(Project Number: S8108232001, S8109008001).
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 623–628, 2011. © IFIP International Federation for Information Processing 2011
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2 The Principles of MDS
( )
Set the Attribute measurement matrix C(C= dij n×n) of n objects has been given in r-dimensional space,said C is the similarity matrix for the n objects. MDS using C to obtain p (p r)-dimensional vector Z = (z (1), z (2), ..., z (n)), and n objects can be exˆ is Attribute measpressed by vector Z, said that Z is a Mimetic Structure of C. Set D ˆ urement matrix Obtained from the Z,and said D is Mimetic distance matrix of C. MDS's target is both to make the n objects to achieve p (p r)-dimensional expression, ˆ as close as possible to C, and the process achieves the classificabut also to make D tion of n objects ,where only n-matrix C is available. Young- Household theorem approachs creating p-dimensional vector Z from the matrix C. For the matrix C = (dij) n × n, set B = (bij) n × n, where
≦
≦
(- + ∑ dij + ∑ dij - ∑∑ dij ) (1) Set λ ≧λ ≧…≧λ is positive characteristic roots of B, e ,e …,e is eigenvector corresponding to λ ≧λ ≧…≧λ take Z = (e , e , ..., e ) = (x ) , each row of Z matrix 1 bij= 2
1
2
dij2
n
1 n
n
1 n
2
j =1
2
i =1
r
1
2
r
1
2
r
n
n
1 n2
i =1 j =1
1
2
2
r
ij n × r
corresponds to a mimetic spatial coordinate of object. Take Z dimension p
3 Land Evaluation Model Based on MDS In the process of anglicizing land information for different types of factors, there is big difference in data preprocessing, such as data quality control, data registration, space unit and so forth, but through a certain mode after pretreatment different sources, different scales, different elements of the land factor in the sampling data can be integrated in an information space, which can study the characteristics of spatial information. Set Xi (i = 1 .... N) is the space evaluation unit of land, and the spatial coordinates is (xi, yj). land evaluation factors subordinate to Xi (i = 1 .... N) constitute a r-dimensional sampled data information space. C is the the spatial similarity matrix of Xi (i = 1 .... N) based on sampled data of land evaluation factors. Z is a Mimetic Structure of Xi (i = 1 .... N),in this mimetic Structure, Xi’s spatial coordinates is (ui , vi). The process of land evaluation based on MDS can be expressed as:
﹛X ﹜(i=1….n):t is the similarity measure matrix constructor; Z=H﹛C﹜:H is constructor to form Mimetic Structure; F =E{(u ,v )}:is spatial clustering for Xi Based on (u , v ) the, E is the analysis process; F=Q{ F }:F is cluster expression of the land evaluation space unit based on C=t
i
,
i
i
i
i
,
,
(xi, yi) , Q is the transformation process of F to F .
4 Realizing Model Taking expropriation division in Xuzhou city as an example, Realizing the Model of land evaluation based on MDS as follows.
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4.1 Establishing Multi-dimensional Information Space Taking village-level administrative areas as the basic spatial unit,and Taking Annual output value of unit land area (PV), affect degree of central city (CD), accessibility to roads (RD), external transport facilitation degree (TD) status of land use (LU), land supply and demand (LS), the local economic development (EL) as the information dimension,establish multi-dimensional information space:
(pv ,cd ,rd ,td ,lu ,ls ,el )
yi
i
i
i
i
i
i
i
Where pvi, cdi, rdi, tdi, lui, lsi, eli is the regular, standardized property value of annual output value per unit area (PV), center city degree (CD), accessibility to roads (RD), external transport facilities degrees (TD) land-use conditions (LU), land supply and demand (LS), the local economic development (EL). 4.2 The Similarity Structure of Spatial Cells Taking pvi, cdi, rdi, tdi, lui, lsi, eli as distance measure, establish Euclidean distance similarity measure between spatial unit i, j: s i = ( pv j − pv i ) 2 + (cd j − cd i ) 2 + (rd j − rd i ) 2 + (td j − td i ) 2 + (lu j − lu i ) 2 + (ls j − ls i ) 2 + (el j − el i ) 2
taking si as a similarity measure to establish spatial attribute similarity matrix of Expropriation Division as a table1 (Local). Table 1. Similarity Matrix of Spatial Cells’ Attribute Zhangxiaolou Zhangzhuang Xinjian Liumalu Pangzhuang Shixi Shidong Linhuang Chengzhuang Gushan Wangxinzhuang Zhoutun Yangxi Zhangxiaolou
0.000
Zhangzhuang
0.040
0.000
Xinjian
0.100
0.137
0.000
Liumalu
0.233
0.247
0.181
0.000
Pangzhuang
0.493
0.467
0.529
0.422
0.000
Shixi
1.515
1.477
1.591
1.535
1.127
0.000
Shidong
0.277
0.284
0.238
0.063
0.373
1.494
0.000
Linhuang
0.325
0.361
0.276
0.430
0.804
1.836
0.493
0.000
Chengzhuang
0.443
0.477
0.343
0.314
0.724
1.846
0.353
0.380
0.000
Gushan
0.779
0.774
0.755
0.577
0.456
1.383
0.516
1.001
0.737
0.000
Wangxinzhuang
0.555
0.556
0.520
0.340
0.374
1.455
0.282
0.759
0.508
0.242
0.000
Zhoutun
0.267
0.307
0.180
0.290
0.693
1.770
0.352
0.159
0.241
0.848
0.606
0.000
Yangdong
0.381
0.392
0.324
0.148
0.428
1.554
0.113
0.547
0.316
0.456
0.214
0.392
0.179
Wutun
0.439
0.464
0.352
0.235
0.594
1.721
0.244
0.495
0.171
0.566
0.339
0.337
0.215
Liwo
1.056
1.061
1.005
0.827
0.819
1.698
0.779
1.204
0.862
0.368
0.510
1.045
0.859
Liulou
0.927
0.938
0.863
0.693
0.781
1.766
0.654
1.037
0.680
0.384
0.422
0.879
0.714
Tianqi
0.753
0.771
0.675
0.525
0.738
1.815
0.502
0.815
0.445
0.471
0.368
0.660
0.529
Yangxi
4.3 Coordinates Calculation of Mimetic Structure Using ALSCAL in MATLAB to calculat the space coordinates (ui, vi) in mimetic structure for each spatial unit as shown in Table 2:
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TLDQSDQWDR
-0.072
0.741
Village Name ]KDRZX
-0.478
-0.184
Village Name [LDGLDQ
MLQJVKDQ
-0.23
-0.134
]KDQJWXQ
-0.223
-0.226
KXDQJVKDQ
0.63
-0.35
GDKXDQJVKDQ
-0.418
-0.029
GDKDQ
-0.384
-0.125
OXRWXRVKDQ
1.075
-0.145
NHOLDQ]KXDQJ
-0.54
-0.066
OL]KXDQJ
-0.564
-0.039
VKL]LVKDQ
0.858
0.046
ZDQJNHOH
-0.73
-0.144
PD]KXDQJ
-0.517
-0.044
[LDKHWRX
0.275
-0.054
Village Name
Coordinate
Coordinate
Coordinate 1.071
0.043
ODQJJXGXQ
-0.825
-0.265
GLQJ]KXDQJ
0.344
1.241
VDQJXDQPLDR
0.727
0.011
[LDRKXDQJVKDQ
-0.765
-0.294
VKDQJKHWRX
-0.097
-0.384
KRXVKDQZR
0.844
-0.224
[L]KXMLD
-0.739
-0.259
GDZDQJPLDR
0.108
0.555
MLDQVKDQ
0.46
0.102
TLDQZDQJMLD
-0.866
-0.083
FKHQJ]KXDQJ
-0.208
0.566
WDLVKDQ
0.617
0.125
SROL
-0.784
-0.138
OLXSX
-0.509
-0.254
FKDSHQJ
0.375
0.224
GDPLDR
-0.777
0.41
FKDDQ
-0.229
0.908
GDVKDQWRX
0.32
0.339
DQUDQ
-0.589
0.365
OLXML
-0.365
-0.752
KDQVKDQ
0.671
0.23
JXVKDQ
-0.474
0.443
]KDRGLDQ
-0.285
0.083
[LQJVKDQ]L
0.179
0.34
]KDQJ]KXDQJ
-0.653
-0.04
VXQGLDQ
-0.258
0.291
VKL]KXDQJ
-0.06
0.106
KRX\DR
-0.66
-0.161
SDQWDQJ
-0.518
-0.009
TXQ\LQJ
0.002
0.119
KRXML
-0.575
0.303
MLDQJORX
-0.557
-0.197
GLQJORX
-0.03
-0.104
TLDQ\DR
-0.562
0.169
WDQJIDQJ
0.078
0.147
VXVKDQ
0.399
0.193
KHWDR
-0.604
0.483
FXL]KXDQJ
0.535
0.922
KXRKXD
0.326
0.242
GRQJFXQ
-0.58
0.205
GXDQVKDQ
0.129
-0.108
GXDQ]KXDQJ
0.878
-0.464
KRXED
-0.688
-0.077
FDRVKDQ
-0.135
-0.229
VKDQJVKDQ
-0.354
0.487
TLDQED
-0.855
-0.001
IHQJ]KXDQJ
-0.3
-0.166
GRQJKH
-0.13
0.347
GDKX
-0.607
-0.021
\DR]KXDQJ
0.58
0.157
[LKH
-0.019
0.01
TLDRKX
-0.102
-0.137
VKLOL
0.505
-0.091
EDOL
0.976
-0.146
FKDQJVKDQ
-0.42
-0.322
ZDIDQJ
0.944
0.111
WXQOL
0.037
0.185
WXVKDQVKL
-0.041
-0.338
GLDQ]L
0.641
-0.074
*Coordinate value ois the relative value of 1 / 1000 as the basic unit
Fig. 1. Mimetic Structure of Spatial Cells
Fig. 2. Partitioning Mimetic Structure
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4.4 Spatial Clustering in Mimetic Structure Realizing spatial visualization of mimetic structure according to coordinates (ui, vi) as shown in Figure 1and realizing spatial cells aggregation according to spatial relations in mimetic structure as shown in Figure 2. 4.5 Implementation of Expropriation Division Transform the classification of spatial cells in mimetic structure into real space to achieve expropriation division, results of the division shown in Figure 3. Figure 4 is the map of actual expropriation distribution, in Xuzhou city. Comparison of Figures 3 and 4, Comparison of Figures 3 and 4, both the spatial distribution between the two is consistent. Indicating the land evaluation method based on MDS meets the requirements of land classification.
Fig. 3. Land Requisition Blocks Partitioned by Multidimensional Scaling
Fig. 4. Actual Land Requisition Blocks of Xuzhou city
5 Summary Land evaluation based on MDS does not rely on priori assumptions, the basic approach is to transform the data into a similar space and complete spatial clustering according to the spatial similarity of the data. The example of expropriation division in Xuzhou city shows that the land evaluation based on MDS meets the requirements of land classification.
References 1. Xue, F.-c., Bian, Z.-F.: GIS combined with MCE to Evaluate Land Quality. In: The First International Conference on Computer and Computing Technology Applications in Agriculture, pp. 365–368 (2007) 2. Páezl, A., Scott, D.M.: Spatial statistics for urban analysis: A review of techniques with examples. GeoJournal 61(1), 53–67 (2005)
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3. Patacchini, E.: Local analysis of economic disparities in Italy: a spatial statistics approach 17(1), 85–112 (2008) 4. Cox, T.F., Cox, M.A.A.: Multidimensional Scaling. Chapman&Hall, London (1994) 5. Young, F.W., Hamer, R.M.: Theory And Applications of Multidimensional Scaling. Eribaumassociates, Hillsdalenj (1994) 6. Borg, I., Groenen, P.J.F.: Modern Multidimensional Scaling:Theory and Applications. Springer, Newyork (1997) 7. Borg, I., Groenen, P.J.F.: Modern Multidimensional Scaling: Theory and Applications. Springer, Heidelberg (2005)
Design and Development of Water Quality Monitoring System Based on Wireless Sensor Network in Aquaculture Mingfei Zhang, Daoliang Li, Lianzhi Wang*, Daokun Ma, and Qisheng Ding College of Information and Electrical Engineering, China Agricultural University, Beijing, China [email protected], [email protected], [email protected]
Abstract. This paper presents a system framework taking the advantages of the WSN for the real-time monitoring on the water quality in aquaculture. We design the structure of the wireless sensor network to collect and continuously transmit data to the monitoring software. Then we accomplish the configuration model
in the software that enhances the reuse and facility of the monitoring project. Moreover, the monitoring software developed to represent the monitoring hardware and data visualization, and analyze the data with expert knowledge to implement the auto control. The monitoring system has been realization of the digital, intelligent, and effectively ensures the quality of aquaculture water. Practical deployment results are to show the system reliability and real-time characteristics, and to display good effect on environmental monitoring of water quality. Keywords: WSN, Water quality monitor, Zigbee, Control, System integration.
1 Introduction China as a huge fishery country produces a great quantity of aquaculture every year in the world. As all known, water quality is very important in aquaculture, so the real-time monitoring and early warning studies on the water environment have been an essential part of aquaculture. At present, most domestic water quality monitoring are still using manual methods. The detection process involved in sampling, sample transportation and preservation, laboratory data measured etc., is a complex but associated system. Any error of the steps will affect the results of the final data. The traditional artificial method as regular or irregular sampling and monitoring is waste of time, inefficient, and difficult to objectively reflect variation rules and facts. It has been unable to meet *
Corresponding author: WANG Lianzhi, master instructor. Research: Application of artificial intelligence.
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current water quality monitoring needs. Along with the quickly development in communication technology and sensor technology, it accelerates the remote monitoring and automatic water quality monitoring process. The real-time water quality monitoring system based on wireless sensor network due to its convenience, real-time, accurate characters, has been get researchers more and more attentions[6-12].
2 System Architecture Based on WSN (Wireless Sensor Network) The process to monitor water quality environment includes data acquisition, data transmission, data preservation and decision-making, which is involved with software and hardware comprehensive integration, so the excellent architecture becomes the top priority to the water quality monitoring system as a composite system. 2.1 Introduction to WSN WSN (Wireless sensor network) is composed of data acquisition node, wireless transmission network and information processing center. Data acquisition nodes integrate sensors, data processing module and communication module. Through the communication protocol, the nodes form a distributed network. Then the network transmits the optimization data to information processing center. The system adopts Zigbee based on IEEE 802.15.4 communication protocol. Zigbee is a wireless intercommunication technique that has low transmitting rate and low cost advantages. It can be embed in devices, is particularly suitable for industrial control, aquaculture water quality monitoring, wireless sensor networks and smart devices such as the widely distributed applications [1-4]. Wireless network monitoring system includes the major technologies:(1)Wireless communication technology—2.4GHz short range communication and GPRS communication, wireless signals cover 3km range; (2)Embed control technology—intelligent information acquisition and control; (3)Wireless network technology—network routing layer, communication caching, self-diagnosis and maintenance technology; (4)Energy manage technology—low power consumption and energy management. Wireless sensor networks are widely used throughout intelligent transportation, environmental protection, public safety, peace at home, smart fire alarm, industrial monitoring, elderly care, personal health, floriculture, food traceability, enemy detection and intelligence gathering, and other fields [5]. Particularly in the areas of agriculture and rural information, WSN can be more widely available, such as: precision agriculture-the precise application of sensor technology, intelligent expert management system, remote monitoring and remote sensing systems, bioinformatics and diagnostic systems, food safety traceability system. 2.2 Water Quality Monitoring System Architecture Applied WSN Based on WSN, the water quality monitoring system uses three-layer structure: data acquisition layer, data transport layer and application layer to establish its architecture. The architecture as figure 1 shows:
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Fig. 1. System architecture based on WSN
In the data acquisition layer, the water quality monitoring system uses WSN which is formed by a large number of tiny sensor nodes through wireless self-organizing way. The sensors obtain data in the network include PH, water level, water temperature, DO (dissolved oxygen) sensor. WSN integrates sensor, MEMS and wireless communication technologies, can real-time perception and handle object’s data information in network range, then send to the users. It has many excellent characters, such as large cover range, remote monitor, high monitoring precision, quick deployment and low cost. Through using WSN technology, the system can effectively monitor transport data and ensure the real-time data to be transported to the water quality monitoring software for analyzing and providing later control decisions. In the data transport layer, there are two types of transmission methods: long-distance and short-distance data transmission. The system uses the GPRS to transport long-distance data, and uses the Zigbee to obtain the sensors’ monitoring data, and then utilizes application software to manage the data and to make decisions to control devices. The real-time data through the sensors by Zigbee stored in the database to ensure users can query any time any sensor monitoring data information to analyze. In the application layer, the water quality monitoring software is the main part. Through the soft ware, users can monitor the quality of the water all the time from the real-time data to ensure the water quality of the aquaculture. Water quality monitoring software utilizes the expert knowledge stored in the data and knowledge database together with the pretreatment data transported from sensors to make the decisions. Then the system decides whether to open or close the valve on relation device to increase or decrease the oxygen, water with the decisions. On-site users can receive early warning information from smart handheld device and depend on the decisions to operate. In order to facilitate user management, and data on water quality issues can occur in time to respond, the software also uses SMS early warning function. Off-site users can receive early warning information from PDA and other smart phones, and can send
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commands by SMS to control the valve on device. The users can not only get the current water quality environmental data, but also analyze the data in period to get the water environment trends to overall manage water quality. The system collects temperature, PH, dissolved oxygen sensor signals by sensor module, via wireless transport module transmit data, and combines with system software to achieve real-time monitoring and control. The system based on users demand, can monitor the water quality data at any time. It provides scientific evidences to automatic monitoring of water quality information, automatic control and intelligent management.
Fig. 2. System structure in application
3 Water Quality Monitoring System Software Architecture and Function Models Water quality monitoring system software can pre-process, display and analyze the data from wireless sensor network, then make the corresponding decisions. Software system architecture and functional modules show as follows. 3.1 Software Architecture The functions of water quality monitoring software in application layer are mainly the water quality data analysis and decision-making. The software development tool is Visual studio 2005, and develops, compile, debug in Windows XP. The software architecture based on .NET framework, using MVC structure, implements the separation of logic layer, display layer and data layer, which improved application scalability and reusability. The software architecture shows as the figure3.
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Fig. 3. Software architecture
In this architecture, the software hierarchical structure has three-layers: display layer, logic layer and data layer. Data acquisition and device control layer is related to the wireless sensor network hardware of the system architecture. The whole workflow process of the software is: firstly each sensor node in the wireless sensor network sends the water quality monitoring data to the water quality monitoring software; secondly in the design project, the users can see the real-time data by double-click the corresponding graphical device, and get the network topology. The user also can get the trends of one sensor data in a period or compare several sensors data in one comparison chart; thirdly according to the water quality data and device status, the users can add/delete device information, change the parameters of the device channel and set the sleeping status to the device for saving the battery power through the device configure module; fourthly through data analysis module, the software calls the knowledge from the knowledge database in the data layer to analyze the water quality data and decides to whether send control commands to the associated devices. The users can real-time monitor and manage aquatic water quality conveniently and efficiently by the various monitoring and control functions that the entire software modules work together to achieve. 3.2 Software Function Modules The software main function modules include project design module, device configure module and data query/store/analyze module. Project design module through the user interface can display real-time data of water quality parameters in the monitoring region, over-limit alarm and historical data records; Device configure module uses communication protocol to communicate with the routing node, in order to achieve data
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transmission and device configuration aims, and in this module sensor network topology can be displayed to users; Data module uses database to implement the storage of the history monitoring data, and provides query and analysis operations to the users. Water quality monitoring software functions structure shows as figure 4.
Fig. 4. Software functions structure
Project design module. The functions in this module are mainly related to water quality monitoring on-site equipment graphical deployment and configuration. The user can present the equipment deployment in a project in a graphical method. It is easy for users to the project management, and users can design several projects for different demands. Each project can not only be reused, but also convenient and highly interactive to user operation. Friendly user interfaces provide the ability that the users can fully control the state of engineering equipment. Module functions include: 1) Drag the graphical devices to the project to implement the deployment; 2) Configure the graphical devices and associate with the actual physical devices address; 3)The graphical devices in the project allow users to drag and drop, double-click to configure properties, view real-time water quality data in the relation device. Current popular model of monitoring software is configuration software. The configuration software which has outstanding specialty such as rich user-defined properties, using flexible, and functions powerful, is a software platform tool for data acquisition and control. Its main contents include good man-machine graphical interface, real-time database, real-time control, communications and networking, open data interface, wide support to I/O devices. As a water quality monitoring software, the configuration of the used devices would help users design and management of the project, so the module uses configuration model on the graphical devices in the development. The graphical devices configuration in the water quality monitoring software include ponds, access node, routing node, collection node, control valves, switches. Users can design the project by dragging and dropping the graphical device from the graphical devices configuration toolbar. All
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graphical devices in the project can be moved, added relations, and viewed the real-time data by clicking in the main project interface. For the collection node and routing node, because they communicate with the software by protocol, the communication state maybe not stabilization in the project. The corresponding graphical device has two states, one green color expresses the good communication state, and the other red color expresses the bad state. Because the communication state refresh in time, the users can manage the device communication state from the project main interface. Also the control device has two state, green expresses the valve open, red expresses close. The control device can be set auto control to implement the operations depend on the monitoring data of the sensor. Users can re-design new projects, and user-designed project can be saved to reuse that implement different management in different projects for the user.
Fig. 5. Project configure interface
Device configure module. The module is mainly related to the physical device information properties, including the address and type of physical device, channel address and type. The functions include: 1) The device attributes configuration; 2) Device-channel attributes configuration; 3) Device parameters configuration, including reading the current configuration and reset the parameters of the device; 4) Device dormant state configuration, including reading the current configuration and reset the device parameters. Device configuration relates to device properties, channel properties, channel parameters, sub-device parameters, system parameters and sleep settings. The device configure main interface shown in Figure 6.
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Fig. 6. Device configure interface
Through this module, users can carry out the parameters of the corresponding device configuration management, and water quality monitoring data and device status data will be stored for use. The changes of hardware devices configuration in the wireless sensor network can be completed by the operations that the device properties add, delete, modify in the project. It makes water quality monitoring software to keep devices properties update and have accurate information in time. In the design project module, graphical device associated with the actual hardware device is through adding the device address to the graphical device. In the device configuration module, the device properties and device channel attributes are need to configure fields as shown in Table 1, 2. Table 1. Device attributes configure data sheet
Primary key PK
Field Name
Field Type
NULL
Description
DevAddr
int
N
Device Address
DevName
varchar
N
Device Name
DevType
int
N
Device Type
DevRole
int
N
Device Role
WorkGroup
int
N
Work Group
Design and Development of Water Quality Monitoring System Table 1. (continued)
DevComm Type ParentDev Addr SIM Area Longitude Latitude MemoryCell InsertTree View
varchar
N
int
N
varchar varchar int int int
N N N N N
int
N
Communication Type Parent Device Address SIM Number Area Longitude Latitude Memory Unit Treeview
Table 2. Channel attributes configure data sheet
Primary Key
Field Name
Field Type
NULL
Description
PK
ChlMark
int
N
Channel Mark
ChlName
varchar
N
Channel Name
ChlDev Addr
int
N
Relation Device Address
ChlDevNum
int
N
Relation Device Channel Number
ChlType
varchar
N
Channel Type
ChlUnit
varchar
N
Channel Unit
ChlAltitude
int
N
Channel Altitude
ChlDotNum
int
N
Decimal Digits
ChlLowerLimit
int
N
Channel Lower limit
ChlUpperLimit
int
N
Channel Upper limit
ChlFieldParaA
int
N
ChlFieldParaB
int
N
Calibration Parameters A Calibration Parameters B
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The software can configure the system parameter such as device storage parameters, including the storage of cycles, the begin record time and the end recorded time to adjust the device stored setting. Since sensor devices in the wireless sensor network rely mainly on battery power energy, in order to ensure the device continued work time, device configure module provides a sleep set. Through the sleep setting, users can control the sensor device periodically stop working, and can wake up when needed in a time. Through the setting, it greatly enhances the device working time. In this module, users can also understand the WSN topology of the network, and can get the current device CPU voltage and battery voltage by double-click the graphics device in the topology that facilitates the management of the current device. Data query/store/analysis module. The module is mainly related to query/store/analysis the monitoring data on the configured device. The functions include: 1) Query and preserve the basic properties of the devices; 2) Query and preserve the basic properties of the device-channel; 3) Query and preserve water quality sensor real-time data; 4)Analyze the graphical device real-time data and make the control command.
Fig. 7. History data analysis interface
Through the preservation of historical water quality data, the users can analyze the water quality monitoring data, view data trends, and grasp the overall trend of water quality. The data preservation include water quality monitoring data and device status data, and the corresponding data fields shown in Table 3,4.
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Table 3. Water quality data sheet
Primary key PK
Field Name
Field Type
NULL
Description
HisData_Index RecordTime HisData_ChlSum HisData_x_x
int Date int int
N N N N
Data Index Record Time Channel Sum Channel Date
Table 4. Device state data sheet
Primary key PK
Field Name
Field Type
NULL
Description
HisSts_Index RecordTime HisSts_ChlSum HisSts_x_x
int Date int int
N N N N
Data Index Record Time Channel Sum Channel Date
Through combined the knowledge in knowledge database with the sensor data in water quality database, the module judged the data whether below the lower limit or higher than the upper limit. If it’s true, the graphical device in the project will be twinkled to alarm the user. And the software if judged the device state was auto state, it will auto send commands to the control device. Analysis flow chart is shown in Figure 8.
Fig. 8. Analysis flow chart
4 Application The wireless sensor network hardware monitoring equipments deployed in the crab ponds of the local famers in Yixing Jiangsu province. Water quality monitoring software deployed in the control room of PengYao ecological park. The application has received good results in practice. Devices deployment shows as figure 9.
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Fig. 9. On-site devices deployment
The steps of monitoring process to the instance of the application are as follows: (1) Wireless acquisition nodes installed in local farmers’ crab ponds, and they are directly connected with the water quality sensors including temperature, water level, PH, DO (dissolved oxygen) sensor to implement the water quality data collection, storage and distribution. Each acquisition node has four sensor interface, can connect up to four sensors to detect five water quality parameters. Acquisition nodes and sensors connected by RS485 communication interface. (2) Routing nodes installed between the crab ponds and monitoring system center receive data from acquisition node and send to the monitoring system center. Use the routing node can extend the communication distance, and ensure the smooth communication. (3) The system using ZigBee protocol transmits data to the water quality monitoring system for the related decision-making. (4) The monitoring system receives the data including water quality data and the node voltage data. Through the water quality data, monitoring system can manage the water quality environment and decision-making. Through the node voltage data, water quality monitoring system can grasp the current energy situation and communication conditions, facilitate equipment maintenance and management. (5) Send control commands to the control device, and send messages to the user PDA to notify the user, the user can remote control valve by SMS.
5 Conclusions In this paper, a system capable of water quality monitoring based on WSN is presented. The system has made several achievements in: (1) Unlike some simulators, this system is a practical monitoring application where sensor nodes periodically send the information they got to the software for decision making and analysis. (2) Wireless sensor network ensures the real-time and reliability of the monitoring data, and sleeping
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setting make the sensor devices work longer. (3) Configuration software model enhances the reuse and facility of the monitoring project, and provides user-friendly management to the users. (4) The monitoring software can represent the monitoring hardware and data visualization, and analyze the data with expert knowledge to implement the auto control. Furthermore, it can send warning (Via SMS or graphical device twinkle) messages to relevant users when undesirable events are detected. Future work will deploy more nodes to provide long-term monitoring. Besides, as the water quality parameters correlation between each other, adding data fusion functions and fuzzy control model, which will greatly improve the accuracy of the system monitoring, it will be the next step in the direction of system development. Acknowledgements. This research was financially supported by the National High Technology Research and Development Program of China (2007AA10Z238), Beijing Natural Science Foundation (4092024), National Major Science and Technology Project of China (2010ZX03006-006) and 948 Project of China Agriculture Ministry (2010-Z13).
References [1] Cao, X., Chen, J., Zhang, Y., Sun, Y.: Development of an integrated wireless sensor network micro-environmental monitoring system. ISA Transactions 47(3), 247–255 (2008) [2] Mainwaring, A., Polastre, J., Szewczyk, R., et al.: Wireless sensor networks for habitat monitoring. In: ACM WSNA 2002, Atlanta, Georgia (2002) [3] Steere, D.C., Baptista, A., et al.: Research challenges in environmental observation and forecasting systems. In: Proc. 6th ACM/IEEE MobiCOM, pp. 292–299 (2000) [4] Chen, D., Zheng, Z., Li, J.: Survey on wireless sensor networks. Computer Measurement& Control (2004) [5] Ren, F., Huang, H., Lin, C.: Wireless sensor networks. Journal of software, 1282–1291 (2003) [6] Wang, P.: Introduction and developing trends of online water quality monitoring system in cultivation. Fishery Modernization (2006) [7] Du, Z., Xiao, D., Zhou, Y., Ou Yang, G.: Design of water quality monitoring wireless sensor network system based on wireless sensor. Computer Engineering and Design 29(17) (2008) [8] Wang, Z., Hao, X., Wei, D.: Remote water quality mentoring system based on WSN and GPRS. Instrument Technique and Sensor (2010) [9] Zhao, J., Song, G., Zhou, C., Wei, J.: Research and application of wireless sensor networks in water quality monitor. Communications Technology 41(04) (2008) [10] Ye, X., Chen, L., Hu, G.: Application of wireless sensor net works in environment monitor. Computer Measurement&Control, 155–157 (2004) [11] Song, D., Chen, Q., Xue, Z., Sun, H., Zhang, J.: Study on water quality monitoring system of multi-points online for seawater industrial fish culturing. Marine Fisheries Research 23(4) (2002) [12] Han, A., He, Y., Li, J., et al.: Design of acoustic signal acquisition system of stored grain pests based on wireless sensor networks. Transactions of the CSAE, 181–187 (2010)
Design of an Intelligent PH Sensor for Aquaculture Industry Haijiang Tai1, Qisheng Ding1,2,*, Daoliang Li1,**, and Yaoguang Wei1 1
,
College of Information and Electrical Engineering, China Agricultural University, Beijing 100083 P.R. China [email protected] 2 Xuzhou Normal University, Xuzhou, Jiangsu, P.R. China
Abstract. Automatic monitoring and controlling system is essential for improvement of aquaculture industry. This paper presents an intelligent PH sensor that applied to water quality monitoring. It involved signal processing, self-calibration. Using low power and high performance microcontroller MSP430F149, Smart Transducer Interface Module (STIM) based on IEEE1451standard was embedded. The design of software and hardware was described in detail, and an initial calibration experiment was carried out to establish a calibration parameter. The results indicate that the pH sensor is more accurate, reliable and easy to use, which is suitable to spread the application in aquaculture industry. Keywords: Intelligent sensor, IEEE1451, PH value.
1 Introduction Over the past decade, the development and applications of chemical sensors and biosensors have grown rapidly. Among all sensors, pH sensors have received the most attention because of the importance of pH measurement in various scientific research and practical applications. China’s water quality online automatic monitoring technology is laggard; a lot of monitoring methods are still traditional, testing data lags behind seriously. Monitoring instrument water quality auto-monitoring system mainly use 2-wire transducers, exist amount of problem, such as poor stability of signal, high cost, single function, can’t connect with field bus control system(Xu hao, 2007). Intelligent of water quality monitoring instrument is important to improve the level and production mode of aquiculture, as a result, amount of intelligent monitoring instruments were developed, more perfectly water quality monitoring instrument were sold by America, Japan, Italy, and so on (Fan Xiang-guo, 2005); at present, water quality monitoring instrument have rapid development in China, various PH * **
Qisheng Ding, contributed equality with Haijiang Tai, and they are co-first author. Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 642–649, 2011. © IFIP International Federation for Information Processing 2011
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monitoring instruments developed by Tsinghua University (Fu Xiao-shi et al., 2004; Gong Yuan-ming et al., 2003), Southeast University (Chen Ming-wei et al., 2005), Jiangsu University (Liu Xing-qiao et al., 2006), and so on. The above water quality PH monitoring instrument bases on MCU generally, monitor single or multiple water quality parameters, achieved electrode calibration and Temperature compensation by using software, but it is difficult to connect with field bus control system (Yang Su-ying et al., 2004). Some instruments can connect with field bus control system, but the problem of the interface and incompatibility are generally exist between multi-sensor and actuator (L.Camara, 2004; Institute of Electrical, 1997; Guangming Song et al., 2005; Antonio Pardo, 2006). In this paper, an intelligent PH sensor was developed according to IEEE145 standard, read sensor data and set actuator parameter by using Transducers Electronic Data Sheets (TEDS) so as to achieved “Plug and play” function (Miroslav S. and Radimir V, 2003). Water temperature and pH can be measured on-line by the intelligent pH sensor.
2 Hardware of the Sensor 2.1 Hardware Structure The sensor mainly contained signal conditioning model, A/D circuit, power source model, microprocessor and Transducers Electronic Data Sheets (TEDS), Hardware structure of the pH sensor is shown in Fig. 1.
pH probe Temperature sensor
Signal conditioning model
microprocessor A/D
MSP430F149
FRAM
TEDS
RS485 field bus
power source model
Fig. 1. Hardware structure of pH sensor
2.2 Hardware Circuit Microcontroller of the sensor is based on MSP430F149 manufactured by TI Company (U.S.A.). The sensor unite adopt an industrial on-line sensor HG990pH and digital temperature sensor DS18B20. Conversion of the current and amplification of the voltage is achieved by using three high impedance, low drift operational amplifiers TLC27L4; two of them make up differential amplifier, and its input resistance up to 3×1012ohm, to ensure the input
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signal not affected by resistance change. Moreover, differential circuit have high CMRR, can adapt to complex Industry-environment. In order to meet the market demand, and meet the requirement of remote transmission and networking, the sensor uses RS-485 field bus to make connection and achieve the communication between CPU and Remote I/O by using a SN75LBC184 RS-232/RS-485 convertor. Two resistors (20ohm in this work), R1 and R5, were series connected to the output terminal of SN75LBC184, avoid network failures of a single hardware device affect network. The electric circuit used to drive the sensor and to treat the signal is shown in Fig. 2.
Fig. 2. Electric circuit for the sensor signal treatment
3 Software of the Sensor 3.1 STIM Master Control Program STIM master control program include (1) finish the initialization of hardware; (2) loading TEDS information; (3) finish self-configuring of STIM Module; (4) setting various special register; (5) initialize working mode for UART; (6) setting working mode for timer and correlative variables; (7) definition of STIM channel. STIM master control program adopt circle inquire, initialize the system after power-on reset, then query data buffer to judge if the command is coming. The management of buffers is achieved by sensor address and function module. If data buffer have data coming, analyze it; if the data is addressing command, call address processing module; if the data is management command of TEDS, call TEDS module. Flow chart of STIM master control program is shown in Fig.3.
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Start System initialize Enter circle
Programming reset
Y
Reset
N Data transmission
Y
Write subprogram
N
Trigger
Read / Write
Y
Read subprogram
Trigger subprogram
N STIM service
Y
STIM service subprogram
N Essential backstage services Return circle
Fig. 3. Flowchart of software for STIM
3.2 Design of TEDS In order to realize the plug and play functionality and self-tuning functionality, Meta-TEDS and Channel-TEDS of TEDS is necessary, besides, Calibration-TEDS and Meta-ID TEDS are also be adopted. STIM module include one Meta-TEDS, two Channel-TEDS which used to store temperature data and input signal of PH sensor, one Calibration-TEDS and one Meta-ID TEDS. The basic design of TEDS is shown in Tab. 1. Table 1. The basic design of TEDS Meta-TEDS
Channel-TEDS
Calibration-TEDS
Data length Data style STIM Channel number Using time limit
Channel number Physics unit
Latest adjust date Adjust interval
Meta-ID TEDS Developer name Development date
Sensor serial number
Adjust parameter
Produce site
Sensor style
Adjust model
Version number
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3.3 Plug and Play Function and Automatic Recognition of STIM Plug and play function and automatic recognition are remarkable features of IEEE1451 intelligent sensor, its implementation principle lie in standard of TEDS was recommended. The table stores all the information about sensor style, physics unit, data style, adjust model and developer ID that corresponding sensor channel. By reading TEDS during use, all the information of STIM channel can be obtained, finish the plug and play functionality. Flow chart of plug and play functionality and automatic recognition is shown in Fig.4.
STIM be detected
Read and analytic Meat-TEDS
Sensor channel exist
N
Y Read and analytic Meat-TEDS of each channel
Adjust TEDS exist
N
Y Read adjust TEDS
set up and configure over Fig. 4. Flowchart of software for plug-and-play and self-identification
3.4 Self-correcting N different gauge point in the range of the PH sensor electronic scale were defined, and M different gauge point in the range of the temperature were defined, standard input
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value of each gauge point come from standard value generator of PH (Y) and temperature (T) respectively as follow: Y i: Y1, Y2…, YN T j: T1, T2…, TM Read the corresponding output values U i and U ii that corresponds to standard input value of each gauge point above mentioned. In this way, the PH sensor calibrating in static states was done at M different temperature states, M different corresponding input and output character cluster (Y-U) were obtained. At the same time, N different input and output character cluster (T-UT) of temperature sensor corresponds to different PH states were obtained too. Calculate the correction coefficient of the two character cluster above mentioned by the least square method; deduce the correction equation of intelligent PH sensor. The correction equation stored in Calibration-TEDS. PH value and temperature signal voltage converts into PH project value after colleted by the microcontroller by using the correction equation stored in Calibration-TEDS, finish the real-time self calibration of PH and temperature sensor signal measurement errors.
4 Experiment The sensor probe used in this work is based on composite glass electrode HG990 manufactured by Shanghai leici instrument Inc. The effect caused by temperature was measured by using PH standard buffer solutions at pH 4.00, 7.00 and 9.00 manufactured by American HACH Company under the range of 0~40 . Calibration experiment did by using PH standard buffer solutions at pH 4.00, 6.93 and 9.41 manufactured by American HACH Company. Experiments were carried out at room temperature, and the measured temperature of standard buffer solution at (26.7±0.1) .Six measurements at 5min intervals were recorded for each standard solution to test reproducibility of the sensor probe by immersing the probe in the solution and lasts 5 min, and then took the probe out after the sensor put out stable signal.
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5 Results and Discussion Fig.5 shows the results of temperature effect. As can be seen, no significant temperature effect in the three PH standard buffer solutions.
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10 9 8 7
eu 6 la V 5 Hp 4 3
pH=9 pH=7 pH=4
2 1 0 0
5
10
15
20
25
30
35
40
Temperature(℃)
Fig. 5. Temperature effect of an intelligent pH sensor
Fig.6 shows the results, voltage changed collected by the sensor for six times below 0.003, the results shows very high reproducibility of the probe and intelligent PH sensor designed in this paper. Calibration curve of the probe fitted according to the principle of least square is y = 4.6667x + 3.1084 , and the correlation coefficient is R 2 = 0.9999 , this result shows high Linearity of the probe. Store the calibration curve into Calibration-TEDS, the signal voltage collected by the microcontroller MSP430 converts into PH project value directly, and put out by RS-485 field bus, finish self-calibration, achieve convenience use.
10 y = 4.6667x + 3.1084 8
2
R = 0.9999
6 PH 4 2 0 0
0.2
0.4
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0.8
1
1.2
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Fig. 6. Calibration results of an intelligent pH sensor
6 Conclusion The intelligent PH sensor based on IEEE1451standard combined traditional sensor, microcontroller and TEDS technology, thus, the sensor was more intelligent. Concrete representations as following:
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(1) Transmit data by applying all- digital bus, easy to apply in monitoring network; (2) Intelligent sensor interface module based on IEEE1451 standard achieved plug and play functionality; (3) Simplified the hardware structures by combining MCU and electrochemistry test technology, expanded measurement function, reduced the cost, improved reliability and measurement precision; (4) Achieved low power consumption by using low power cost MCU (msp430). Acknowledgements. This work was supported by 863 programs “Research and Application of Digital Integrated System for Intensive Aquaculture” (2007AA10Z238), 948 Project of China Agriculture Ministry (2010-Z13). And the programs “Development and Applications of sensor network applied to monitor bloom of blue-green algae in Taihu Lake” (2010ZX03006-006).
References 1. Xu, H.: Development of fishery equipment and engineering science in China (2005-2006). J. Fishery Modernization 34, 1–8 (2007) (in Chinese) 2. Fan, X.-g.: Analysis of aquaculture development of 2004 and prospect of 2005. J. China Aquaculture 1, 3–5 (2005) (in Chinese) 3. Fu, X.-s., Zhang, P., Zhang, H.-y., Wu, J.-h.: Real-time Meter Measuring pH, Conductivity and Turbidity for Groundwater. J. Instrument Technique and Sensor 11, 14–19 (2004) (in Chinese) 4. Gong, Y.-m., Wang, J.-j., Xiao, D.-y.: The design of intelligent industrial acidity meter based on embedded PC. J. Process Automation Instrumentation 8, 25–28 (2003) (in Chinese) 5. Chen, M.-w., Zhou, X.-p., Liu, X.-n.: Design of ATmega16 based on-line measurement and control instrument for pH value. Journal of Southeast University (Natural Science Edition) 11, 77–78 (2005) (in Chinese) 6. Liu, X.-q., Sun, Y.-k., Zhao, D.-a., Cheng, L., Zhao, B.-h., Qin, Y., Xu, W.-z.: Research on intelligent supervising and control system about factors of aquiculture. J. Chinese Journal of Scientific Instrument 27, 527–530 (2006) (in Chinese) 7. Yang, S.-y., Yin, J.-p., Zhong, C.-q., Zhang, L.-y., Li, Z.-h.: Study and Implementation of pH Intelligent Measuring Technology. J. Instrument Technique and Sensor 10, 7–10 (2004) (in Chinese) 8. Camara, L.: Automatic generation of intelligent instruments for IEEE 1451. J. Measurement 35, 3–9 (2004) 9. Institute of Electrical, Electronics Engineers, Inc. IEEE Standards for a Smart Transducer Interface for Sensors and Actuators-Transducer to Microprocessor Protocols and Transducer Electronic Data Sheet (TEDS) Formats, New York, USA Institute of Electrical, Electronics Engineers, Inc. (1997) 10. Song, G., Song, A., Huang, W.: Distributed measurement system based on networked smart sensors with standardized interfaces. J. Sensors and Actuators A 120, 147–153 (2005) (in Chinese) 11. Pardo, A., Camara, L.: Gas measurement systems based on IEEE1451.2 standard. J. Sensors and Actuators B 116, 11–16 (2006) 12. Miroslav, S., Radimir, V.: Integrated Smart Sensor Networking Framework for Sensor-based Appliances. IEEE Sensor Journal 5, 579–586 (2003)
A Simple Temperature Compensation Method for Turbidity Sensor Haijiang Tai1, Daoliang Li1,*, Yaoguang Wei1, Daokun Ma1, and Qisheng Ding1,2 1
College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, P.R. China [email protected] 2 Xuzhou Normal University, Xuzhou, Jiangsu, P.R. China
Abstract. Turbidity sensor for water treatment applications are based on scattered light measurement. The electrooptical characteristic of light emitter and detector has a close relationship with the environmental temperature. Fluctuations in water temperature can potentially affect electronic components and cause output signal errors in turbidity sensor. Decrease or eliminate temperature error is necessary. With this background we have taken the temperature experiment of turbidity sensor developed by us. 11 different concentrations were measured, ranging from 0 to 100NTU. Each solution was cooled to 1 , and then gradually heated to 40 . The output signal of sensor increased according to the rise of temperature found from the experiment. In order to compensate the temperature errors, we developed a novel method to take temperature compensation by using software. The method carried by MCU which is used to compensate the measurement errors by soft programming is simple and effective; it can improve the error compensation precision on sensors greatly.
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Keywords: Turbidity Sensor; Temperature compensation; software compensation.
1 Introduction Along with the development of society, the effect of water is strengthening in people’s live and industrial production day after day. Turbidity is regard as a key technical parameter in the water quality measurement. As an instrument measuring turbidity, turbidity sensor is widely used in water analysis and treatment processes (e.g., Gong Dian-ting et al., 2008; Brasington, J. et al., 2000; Gippel, C.J., 1995; Jack Lewis, 1996). Turbidity sensor for water treatment applications are based on scattered light measurement. When a light beam from the light emitter (for example, light emitting diodes(LED)) passed through a water sample, particles in the light path change the direction of the light and scatter it, scattered light received by the detector (for example, photodiode, phototriode and photoresistance). But the electrooptical characteristic of *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 650–658, 2011. © IFIP International Federation for Information Processing 2011
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light emitter and detector has a close relationship with the temperature. Fluctuations in water temperature can potentially affect electronic components and cause output signal errors in turbidity sensor (Lawler and Brown, 1992). In the practical work, due to the sensor’s environment temperature changed greatly, more heat output caused by variation in temperature can bring about a big measurement error, static characteristic of the sensor will also be influenced. Consequently, temperature compensation must be adopted. Temperature compensation technologies include (1) parallel temperature compensation; (2) zero point temperature compensation; (3) temperature compensation based on software (Du Yong-ping and He Xiao-ying, 2009; J.A. Siqueira Dias et al., 2008). In theory it can be compensated completely by using parallel temperature compensation, but in practical it is only proximate compensation; zero point temperature compensation have high accuracy, but it is difficult to find the material; it is a simple, effective method to take temperature compensation by using software, and an approach to increase the accuracy of sensor measurement (Xu Jun, 2002; Matej Možek et al., 2008). As long as the mathematical model of measuring temperature error is established accurately, temperature compensation of sensor can realize well. In this work, the ambient-temperature influence on a turbidity sensor, which was maintained with a constant temperature difference from that of the solution, was analyzed and a simple temperature compensation method proposed.
2 Temperature Effect Mechanism The sensor is consist of many parts, electronic components (such as resistor, capacitor) of signal conditioning circuit are not effected by temperature change. But the electrooptical characteristic of light emitter and detector has a close relationship with the temperature. 2.1 Temperature Influence on LED LED will suffer high power dissipation and self-heating at work, and its luminous intensity has a close relationship with the environmental temperature. Along with the increase in environmental temperature, there is a decrease in radiation intensity of LED, and the peak wavelength shifts to longer wavelength (B.P.J. de Lacy Costello et al., 2008). Radiation intensity was proportional to the logarithm of environmental temperature. Compared with the environmental temperature at 25 , When the environmental temperature at 40 , relative light output will decreased to 70%~80%, the accuracy of turbidity sensor will be influenced directly (Sheng Qiang and He Xiao-gang, 2007). Under the constant input current, output optical power of LED decreased according to the rise of temperature, as Fig. 1 shows. Fig. 2 shows the peak wavelength shifts and relative light output of each color LED according to the rise of temperature shown in Fig. 3.
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output optical power (mw)
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T1
T2
input current (mA)
Fig. 1. Temperature characteristic of LED (T2
>T1)
Tamb = −20°C
+ 25°C + 85°C
Fig. 2. Peak wavelength under different temperature
200% 150% 100% 50% 0% -40
-20
0
20
40
60
℃)
80
100
120
Temperature(
Fig. 3. Relative light output of LED according to temperature change
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2.2 Temperature Influence on Silicon Photoelectric Generator Take the silicon photoelectric generator as detector. Along with the increase in environmental temperature, there is a rapid decrease in open-circuit voltage, and an increase in short-circuit current. Moreover, open-circuit voltage and short-circuit current both have a linear relation with temperature(Zhang Wei et al., 2009). Fig.4 shows the temperature characteristic of silicon photoelectric generator.
Voltage(mV)
,
Fig. 4. Temperature characteristic of silicon photoelectric generator
3 Materials and Methods 3.1 Chemical and Equipment All solutions were prepared with filtered water and analytical grade chemicals. A 400NTU Formazin stock suspension was prepared by mixing equal volumes of 100mg/mL hexamethylenetetramine; (CH2)6N4 and 10mg/mL hydrazine sulfate solution N2H4H2SO4, after that, the mixture was let to stand for 24 h at 25±2 in a topaz bottle before the measurements. Filtered water was used as a carrier. In this work, measuring cylinder and Bunsen beaker were used to dilute Formazin standard solutions, and prepared the water samples. A fridge to cool the water samples, and a constant water bath was used to change the temperature of water samples.
℃
3.2 Turbidity Sensor The turbidity sensor used in this work was developed by us. The sensor mainly contained signal conditioning model, power source model, optical measurement system, constant-current source, temperature sensor, RS485 field bus, microprocessor and Transducers Electronic Data Sheets (TEDS), Hardware structure of the turbidimeter is shown in Fig. 5.
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Fig. 5. Hardware structure of the turbidimeter
The sensor is based on a high-power infrared light emitting diode (LED). The reason for select IR LED as following: (1) Turbidity measurement affected by organic substance in water samples, the light wavelength below 500nm can be absorbed seriously; (2) According to ISO 7027 using light with λ>800 nm can minimize interferences caused by the presence of dissolved light-absorbing substances(Dag Hongve and Gunvor Åkesson, 1998); (3) Water samples colour absorbs light of certain wavelength, and affect measurement precision, near infrared light can minimize interferences caused by water samples colour. Consequently, the LED used in this work is designed for maximum emittance at 940 nm. The detector is a matching, high sensitivity Silicon Photoelectric Generator with peak sensitivity also at 940 nm. Both the emitter and detector provide a narrow and closely matched spectrum. The electric circuit used to drive the sensor and to treat the signal is shown in Fig. 6. Conversion of the Silicon Photoelectric Generator current and amplification of the voltage is achieved by using one wide range of input offset, low offset voltage drift, high input impedance, extremely low power, and high gain quad operational amplifiers (TLC27L4). Power requirements for the sensor are +3.3V for the operational amplifiers.
Fig. 6. Electric circuit for the Turbidity sensor signal treatment
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3.3 Methods To measure the response of the sensor to different temperature, Turbidity standard solutions of Formazin were adjusted with filtered water into water samples of 0-100NTU. 11 different concentrations were measured, ranging from 0 to 100NTU. Take Bunsen beaker filled with Formazin standard solution and cooling to 1 , then immerse the sensor in the solution. The Bunsen beaker and sensor were then placed in a water bath at room temperature. Solution in the Bunsen beaker was gradually heated to 40 and the output recorded at 5s intervals.
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4 Results and Discussion 4.1 Calibration of Sensor Table1 shows the relationship between the turbidity of water samples prepared by diluting turbidity standard solutions of Formazin and the values measured by the sensor under environment temperature 20 . As can be seen, the solutions measured gave nearly linear relations between the concentration of the standard solutions and the measured turbidity. Calibration equation of the sensor fitted according to the principle of least square is y = 1.0003 x − 0.0181 , and the correlation coefficient is R 2 = 0.9993 .
℃
Table 1. Relationship of measured turbidity and concentration of turbidity standard Water samples/NTU
measured values /NTU
5 10 20 30 40 50 60 70 80 90 100
5.50 10.55 19.42 29.39 39.37 49.35 59.88 71.52 80.38 90.92 98.68
correlation coefficient R2 0.9993
4.2 Temperature Effect Fig. 7 shows the relationship between temperature and the output signal of sensor. As the figure shows, the experimental curves seem to be similar in shape to each other, but had larger values as solution concentrations increased. The output signal of sensor
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increased according to the rise of temperature found from the experiment. But the output signal of sensor decreased according to the rise of temperature found from the experiment at initial stage, this result probably arose from the temperature between the sensor and solution failed to come up to equilibrium, the temperature of sensor is higher then solution.
550
2
y = 0.2131x - 6.3821x + 432.32 2
R = 0.9973
500
80NTU
2
y = 0.1303x - 0.5072x + 255.9
450 ) V m ( l400 a n g i s t350 u p t u O300
2
R = 0.9923
40NTU
2
y = 0.142x - 2.3413x + 254.9 2
R = 0.998
10NTU
2
y = 0.1478x - 2.5972x + 237.4 2
R = 0.993
0NTU
250 200 0
5
10
15
20
25
30
35
40
Temperature(℃)
Fig. 7. Relationship of temperature and output signal of sensor
5 Temperature Compensation As Fig. 7 shows, when the temperature was in the range of 1
~40℃, the relationship
between the output signal of sensor and temperature can be given by
y = mx2 + nx + p
(1)
Where y , is the output signal of turbidimeter, x is temperature, m , n and p is coefficient. Consequently, a general curve can be obtained as Fig. 8 shows. Three points A(x 0 , y 0 ) B(x1 , y1 ) and C(x 2 , y 2 ) on the curve in Fig.8 can be used
,
to solve the quadratic equation (1). But it is difficult to solve the quadratic equation (1) directly. Another form of the quadratic equation (1) as follow can be used.
y = a( x − x0 )( x − x1 ) + b( x − x2 ) + c Where
a
, b and c is coefficient.
(2)
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y
y2 y1 y0
C
B A
x0
x1
x2
20
Fig. 8. General curve of the relationship between temperature and output signal of sensor
Substitute the quantitative data of A(x0 , y 0 ) , B(x1 , y1 ) and C(x 2 , y 2 ) into equation (2), the three coefficients can be obtained, and the results as follow:
y2 − y0 y1 − y0 y 2 − y0 − −b x2 − x0 x1 − x0 x2 − x0 a= = x2 − x1 x2 − x1 b=
y1 − y0 x1 − x0
c = y0 + ( x2 − x0 ) When the temperature is 20
y1 − y0 = y0 + ( x2 − x0 )b x1 − x0
℃, output signal of sensor is given by
y = a(20 − x0 )(20 − x1 ) + b(20 − x2 ) + c
(3)
Then substitute the equation (3) into calibration equation of the sensor which obtained at temperature of 20 . Reference value of the solution can be acquired finally. The above-mentioned method is designed to program, and be carried by MCU which is used to compensate the measurement errors by soft programming.
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6 Conclusion In the detection system, the high measurement accuracy is required, and decrease or eliminate temperature error is very important. By the experiment, the following results were obtained:
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(1) The output signal of sensor increased according to the rise of temperature found from the experiment, and a quadratic equation give the best fit. (2) The method carried by MCU which is used to compensate the measurement errors by soft programming is simple and effective; it can improve the error compensation precision on sensors greatly. Acknowledgements. This work was supported by 863 programs “Research and Application of Digital Integrated System for Intensive Aquaculture” (2007AA10Z238), 948 Project of China Agriculture Ministry (2010-Z13). And the programs “Development and Applications of sensor network applied to monitor bloom of blue-green algae in Taihu Lake” (2010ZX03006-006).
References 1. Gong, D.-t., Li, F.-h., Fan, Z.-g., Tao, J., Liu, S.-l.: Measurement of CL− and SO42 − in boric acid by turbidimeter. J. Inorganic Chemicals Industry 40, 56–58 (2008) 2. Brasington, J., Richards, K.: Turbidity and suspended sediment dynamics in small catchments in the Nepal Middle Hills. Hydrol. Process. 14, 2559–2574 (2000) 3. Gippel, C.J.: Potential of turbidity monitoring for measuring the transport of suspended solids in streams. Hydrol. Process. 9, 83–97 (1995) 4. Lewis, J.: Turbidity-controlled suspended sediment sampling for runoff-event load estimation. J. Water Resource 32, 2299–2310 (1996) 5. Lawler, D.M., Brown, R.M.: A simple and inexpensive turbidity meter for the estimation of suspended sediment concentrations. Hydrol. Process. 6, 159–168 (1992) 6. de Lacy Costello, B.P.J., Ewen, R.J., Ratcliffe, N.M., Richards, M.: Highly sensitive room temperature sensors based on the UV-LED activation of zinc oxide nanoparticles. J. Sensors and Actuators B: Chemical 134, 945–952 (2008) 7. Sheng, Q., He, X.-g.: The Far-infrared LED and the Detection of Water’s Turbidity. J. Sci-Tech Information Development & Economy 17, 274–275 (2007) (in Chinese) 8. Zhang, W., Yang, J.-f., Yan, Q.-g.: Experiment research on the property of silicon solar cell. J. Experimental Technology and Management 26, 42–46 (2009) (in Chinese) 9. Siqueira Dias, J.A., Leite, R.L., Ferreira, E.C.: Electronic technique for temperature compensation of fibre Bragg gratings sensors. J. AEU - International Journal of Electronics and Communications 62, 72–76 (2008) 10. Du, Y.-p., He, X.-y.: Brief discussion on temperature compensation technology of sensor. J. Electronic Design Engineering 17, 63–64 (2009) (in Chinese) 11. Xu, J.: Using S-C Processor Software to Achieve the Sensor’s Temperature Error Compensation. J. Modern Electronic Technique 10, 97–99 (2002) (in Chinese) 12. Možek, M., Vrtačnik, D., Resnik, D., Aljančič, U., Penič, S., Amon, S.: Digital Self-Learning Calibration System for Smart Sensors. J. Sensors and Actuators A: Physical 141, 101–108 (2008) 13. Hongve, D., Åkesson, G.: Comparison of nephelometric turbidity measurements using wavelengths 400–600 and 860 nm. J. Water Research 32, 3143–3145 (1998)
A Wireless Intelligent Valve Controller for Agriculture Integrated Irrigation System Nannan Wen1, Daoliang Li1,*, Daokun Ma1, and Qisheng Ding1,2 1
College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, P.R. China [email protected] 2 Xuzhou Normal University, Xuzhou, Jiangsu, P.R. China
Abstract. Based on the problems caused by current automatic irrigation system with a large number of cables, such as installation, maintenance, and difficult expansion, this paper proposed a wireless integrated irrigation control system and developed a wireless intelligent valve controller which can satisfy the requirements for agricultural irrigation in our country. The controller consisted of the control unit, power unit, wireless communication unit, relay boost driver unit, state feedback switch, etc. It received the control command from the remote control center by the wireless communication unit, actuated the relay boost driver unit to turn on/off irrigation solenoid valves. The controller includes the functions of remote control, parameter setting, feedback status detecting, etc. Since the rational design, simple command, and low cost, the controllers have been pilot in Beijing and Xinjiang. The results indicate that the controller is effective in practice and can be used a normal irrigation season. Keywords: Wireless, Valve controller, Irrigation system.
1 Introduction With the popularization and improvement of water-saving irrigation technology, agricultural irrigation control technology is applied gradually. However, irrigation control equipments in application at this stage are from abroad and also very expensive, which are only for demonstration and lack of significance for promotion. Current automated irrigation system with a large number of cables brings many problems such as installation, maintenance, expansion and other issues. Therefore, it is hot to develop a low-cost irrigation valve controller independently for agriculture irrigation system. For example, a low cost solar-powered feedback controller for DIC of fixed irrigation systems was developed. The controller uses soil water potential (SWP) measurements to control the amount of water applied to each specific management area of a field, and measured system hydraulic pressure to communicate with other controllers. The results indicate that the controller was *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 659–671, 2011. © IFIP International Federation for Information Processing 2011
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effective in maintaining the SWP in the root zone close to a predetermined management allowed deficit (MAD). (F.R. Miranda et al, 2005) A wireless broadcast irrigation control system and a low power wireless DC solenoid valve based on OOK modulation and powered by battery were design and applied throughout the greenhouse irrigation in a plantation. (Shen Changjun et al, 2009) With advanced electronic computer control and wireless transmission technology, a precision irrigation control system was designed for water-saving irrigation. (Kuang Qiuming et al, 2007) A new automatic smart controller for irrigation based on GSM network has been developed, it can receive GSM message from PC and mobile, then control the valves by wireless radio communication. (Yang Genghuang et al, 2005) Many irrigation-scheduling methods have been developed over the years, but adoption by producers has been limited by cost, installation time, maintenance, and complexity of the decisions involved. (F.R. Miranda et al, 2005) The above-mentioned irrigation controllers which used OOK modulation, infrared, GSM and other means of communication bring with high price and high maintenance costs. Besides, most commercially available sensors and actuators assembled for irrigation system networks are too complex and/or costly to be feasible for site-specific management of integrated irrigation systems. A wireless intelligent valve controller for site-specific management and/or operation of a wireless integrated irrigation control system is easier to install and maintain as compared to cable irrigation control. As a result, a potential solution to these problems is a total wireless automation of irrigation control system. Wireless automation irrigation controllers can be implemented using spatially variable irrigation systems to optimize yields and maximize water use efficiency for fields with variation in water availability due to different soil characteristics or crop water needs. (Zhang Wei et al, 2009) The objectives of this research were to develop and test an autonomous, low cost, wireless intelligent irrigation valve controller for wireless integrated irrigation control system for the actual demands in agricultural irrigation.
2 Architecture of Wireless Integrated Irrigation Control System Integrated agricultural production demands and learning from foreign experience in research, the architecture of wireless integrated irrigation control system is shown in Fig. 1. The system was composed of two parts, wireless sensors monitoring network and remote control center. Wireless sensors monitoring network consists of wireless information acquisition nodes and irrigation control nodes distributed in the field, the remote control center sends the commands of data acquisition and valve control though the routing nodes. Wireless sensors monitoring network uses star topology, end nodes route by way of the routing nodes to the sink nodes, then the sink nodes transmit information to the wireless access point by GPRS and control computer receives
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information from the wireless access point by RS232. Information acquisition, remote control, parameter setting, intelligent alarm functions are achieved by the remote control center. The system passed soil information and meteorological parameters collected by sensors in real-time monitoring to the remote control center though wireless network. Then the remote control center automatic analysis and makes irrigation management decision to open or close valves. With timely scientific guidance amount of irrigation, the system achieved the sustainable use of water resources and automatic and intelligent irrigation. The remote control center can also share information across users through the Internet.
Fig. 1. Architecture of wireless integrated irrigation control system
3 Materials and Methods 3.1 Irrigation Valve Controller Description For irrigation implementation, a field is typically divided into irrigation management units based on soil characteristics, crop water requirements, and/or economic factors prior to the installation of the control system. A wireless integrated irrigation control system is installed in each irrigation management unit to monitor soil temperature, humidity and meteorological parameters and ensure water-saving irrigation. The valve controller developed in this study is designed to work autonomously without hard-wire connections between individual control units. Each controller is
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designed to operate on battery power. Soil moisture determinations and irrigation decisions occur at fixed regular intervals set by the remote control center. Real-time clocks for all controllers are synchronized for measurement and irrigation decisions. After measurements and irrigation decisions are made, remote control centre sends signal to valve controllers. Each controller installed in system is programmed to process the control commands received from remote control centre to autonomously open an irrigation solenoid valve, triggering relay boost driver unit. Finally, each controller stores the corresponding valve status feedback information from state feedback switch and transmits to remote control center. 3.2 Controller Hardware Wireless Intelligent Valve Controller shall be the core of the wireless irrigation control node, hardware modularization was adopted. It consisted of the control unit, power unit, wireless communication unit, relay boost driver unit, state feedback switch, etc. A block diagram of Wireless Intelligent Valve Controller hardware developed in this study is shown in Fig. 2. Electronic devices, chips, MCU were selected to meet the low power and low cost required for the controller. The sub-components of the control unit are a microcontroller, reset circuit, real-time clock, UART, IO expansion, analog-to-digital (A/D) acquisition, flash memory, and Interface circuit. Each irrigation controller controls four solenoid valves.
Fig. 2. Block diagram of Wireless Intelligent Valve Controller developed in this study
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3.2.1 Control Unit The microcontroller (MCU) consists of the Jennic5139, is the master device of control unit that is programmed to keep time and control the actuators. The device integrates a 32-bit RISC processor, with a fully compliant 2.4GHz IEEE802.15.4 transceiver, 192kB of ROM, 96kB of RAM, and a rich mixture of analogue and digital peripherals. The JN5139 is a low power, low cost wireless microcontroller suitable for IEEE802.15.4 and ZigBee applications. It has 96kB RAM for share program and 192kB ROM for program code. It’s peripherals include a 56-pin DIP package with 21 digital I/O pins, 4-input 12-bit ADC, 2 11-bit DACs, 2 comparators, 2 Application timer/counters, 3 system timers, 2 UARTs, SPI port with 5 selects, 2 wire serial interface, etc. These features all make for a highly efficient, low power, single chip wireless microcontroller for battery-powered applications. This MCU was selected based on low-cost, processor speed, low power requirements, rapid software development, and ease of system integration with custom circuits. The reset circuit and clock circuit ensure equipments work reliability and stability. The JN5139 has two independent Universal Asynchronous Receiver/Transmitter (UART) serial communication interfaces. The UART connected to a level shifter connector to provide the RS232/RS485 line voltage compatible with a PC. The software developer kit uses such an interface as the debugger interface between the JN5139 and a PC. The information can be observed directly in local with RS485/RS232 communication. There are 21 Digital I/O (DIO) pins, which can be configured as either an input or an output, and each has a selectable internal pull-up resistor. Most DIO pins are multiplexed with alternate peripheral features of the device. The Serial Peripheral Interface (SPI) allows high-speed synchronous data transfer between the JN5139 and peripheral devices. The JN5139 operates as a master on the SPI bus and all other devices connected to the SPI are expected to be slave devices under the control of the JN5139 CPU. The Intelligent Peripheral (IP) Interface is provided for systems that are more complex, where there is a processor that requires a wireless peripheral. The intelligent peripheral interface is a SPI slave interface and uses pins shared with other DIO signals. The interface is designed to allow message passing and data transfer. The controller with above DIO pins and interface circuitry can support 4-way analog inputs, 4-way control power output. A controller can support 2-way pulse solenoid valves and state switch, 2-way soil moisture sensor. Controller extends Flash memory. Data and program are stored in non-volatile memory to prevent loss if a power failure occurs. The user can download recorded data to analyze system performance.
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3.2.2 Power Unit Two 1.5V batteries as the input source through the power unit provide a stable output voltage for other units. Power unit contains polarity protection circuit and voltage regulator circuit. Polarity protection circuit includes Schottky diode and the decoupling capacitors. Voltage regulator circuit utilizes voltage regulator chip to ensure output voltage stably. After fully considering energy in application field, controller utilizes ordinary battery as power supply to ensure that the system works over an irrigation quarter. 3.2.3 Wireless Communication Unit ZigBee is a two-way wireless communications technology in short distance communication, with low complexity, low power consumption, low data rate. Its complete protocol stack is only 32 KB, can be embedded in a variety of devices, while support geographic targeting. It is a protocol specification developed for small device wireless network. It is a part of the family of IEEE wireless network protocol. It has a very complete hierarchy. Wireless communication unit supported by low-power radio frequency chip with the typical external circuitry, communicated with the control unit by MCU interface and completed the wireless transceiver function. It works in the global free public band (2.4GHz), reducing the traditional wireless operating cost. 3.2.4 Relay Boost Driver Unit In sleep mode, relay boost driver unit is off. Once the controller receives the valve-driven control signal, it enables relay boost driver unit. Low-power boost chips installed in the relay boost driver unit circuitry will boost the low input voltage to 5 ~ 24V working voltage suitable for solenoid valve, send the driver pulse to control valve. Finally, each controller stores the corresponding valve status feedback information from state feedback switch and transmits to remote control center. The valve controller uses 3V battery as power, based on ZigBee protocol, waiting for remote control command. It can actuate relay boost driver unit to control valve. The MCU collects the state feedback information in real-time and transmits to remote control center. The controller supports a number of pulse solenoid valves from various valve manufacturers and can be easy to installation and operation. 3.3 Controller Software There are 4 kinds of the operation states during the controller working: the initial state, the task query state, the task execution state, sleep state. Diagram of specific state transition is shown in Fig. 3. After the wireless valve controller was powered into the initial state, the microcontroller completed hardware initialization, including the port initialization, watchdog initialization, the system clock initialization, and variable initialization, etc. Then the
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Fig. 3. Diagram of specific state transition Star
Initialization No Register to routing node? Yes No
Receive the control order? Yes
valves control
status detecting
parameter setting
Task execution
Idle?
No
Yes Sleep
Wake up
Fig. 4. Flow diagram of controller program
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controller starts testing a higher-level control signal which drives it into the task query state. If the wireless communication unit detected execution signal, the microcontroller will further determine the type of tasks, for instance, valve control, status detecting, parameter setting, and then enter the task execution state. If no task is detected, the controller enters sleep state. It will be wake up automatically by software timing, then checks control signal again and enters into the task query state. The irrigation controller program was written in C. The program uses the memory capacity of the microcontroller (MCU). The program flow diagram is shown in Fig. 4. It contains a main loop and several subroutines such as valve control, status detecting, and parameter setting that enable the MCU to perform the following tasks: - initialize hardware, including the port initialization, watchdog initialization, the system clock initialization, variable initialization; - register to routing node in the same network, report device information; - request tasks from superior; - query tasks, receive remote control commands; - process the remote commands to determine the type of tasks, execute the task - store control information, time, and valve status in the controller memory; - receive control commands from remote control center to drive irrigation valve; 3.4 Irrigation Valve Controller Testing To measure the valve controller performance, a resistor circuit is used to series connect with the controller (Fig. 5). The circuit was powered by battery. Using a small resistor, resistance on the circuit can be neglected in the energy. Measured the voltage across the resistor by oscilloscope, circuit current value can be obtained in the series circuit to calculate the energy consumption of valve controller. battery
oscilloscope
small resistor valve controller
Fig. 5. Resistor circuit used to calculate the valve controller energy consumption
The valve controller during operation including the initial state, the task query state, the task execution state and sleep state. To facilitate the analysis, the above conditions are divided into the state of active and sleep. Active Consumption Pw can be calculated using the equation:
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Pw = I w × Tw
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(1)
I w is the Active Current, Tw is the Active Time for the valve controller. The Average active current I wa can be obtained by the following equation: Where
I wa =
∑ Iw × T ∑ T + Ts
w
(2)
w
Where Ts is the Sleep Time. Similarly, Average sleep current using the equation:
I sa =
I s × Ts
Isa can be calculated (3)
∑ Tw + Ts
Is is the Sleep Current. The relationship among the Average active current I wa , Average sleep current Isa and Average current Iav is as follows: Where
I av = I wa + I sa
(4)
Consequently, Consumption in one day Pwa is the average current consumption for each hour multiplied by 24 hours per day, the formula can be given by
Pwa = I av × 24
(5)
Through analysis of valve device energy consumption in different states on one day in laboratory, we estimate the actual duration in work as follows. Days:
D=
1200 I av
(6)
D 30
(7)
Months:
M=
4 Results and Discussion The controller performance was evaluated at demonstrations in Beijing and Xinjiang. To verify adequate operation of the hardware and software, and the controller in the root zone on a real-time basis, some controllers were tested to simulate a site-specific irrigation system in laboratory. We chose one of them to analyze its consumption.
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4.1 System Hardware and Software Performance
The controller hardware and software performed all tasks as designed. Data downloaded from the controllers showed that the irrigation control system continually measured apparatus parameters and status information, and opened or closed the solenoid valve when needed without failure. User interactions with the controllers using a notebook computer were also successful. 4.2 Consumption Current in Active and Sleep State
Using two ordinary batteries to power the valve controller, about 1200mAh, specific test results are as follows. Table 1. Valve controller power consumption current in active and sleep state
I w (mA)
Tw (ms)
pw (mAys)
I s (mA)
10.000
2.5
0.025
0.300
20.000
2.0
0.040
0.300
40.000
1.5
0.060
0.300
70.000
1.5
0.105
0.300
40.000
2.5
0.100
0.300
140.000
2.0
0.280
0.300
60.000
3.5
0.210
0.300
140.000
1.0
0.140
0.300
50.000
100.0
5.000
0.300
Valve controller power consumption current in active and sleep state is shown in Tab.1. The range of active current I w is between 20 ~ 140mA, the operating current is 50mA in most of the time and the sleep current is 0.3mA. Total active time is 114.0 ms. 4.3 Average Energy Consumption and the Working Duration
As the sleep time is set by software, furthermore the different sleep time preprogrammed will affect the energy consumption, we test the different average current under the different circumstance. According to the different average current, we can further compute the number of days that the irrigation controller could operate without external charging at the study.
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Table 2. Controller average energy consumption and the working duration
Ts (ms)
I wa (mA)
I sa (mA)
I av (mA)
10000
0.586810
0.297
0.883
20000
0.295068
0.298
30000
0.197084
40000
P
D(d)
M(m)
21.202
56.598
1.887
0.593
14.241
84.265
2.809
0.299
0.496
11.903
100.817
3.361
0.147953
0.299
0.447
10.730
111.832
3.728
50000
0.118430
0.299
0.418
10.026
119.690
3.990
60000
0.098729
0.299
0.398
9.556
125.578
4.186
120000
0.049411
0.300
0.349
8.379
143.214
4.774
180000
0.032951
0.300
0.333
7.986
150.258
5.009
600000
0.009890
0.300
0.310
7.436
161.377
5.379
av
Tab.2 shows controller average energy consumption and the working duration. The sleep time Ts was default in the program. The table lists 10s to 10 minutes of sleep time. The average energy consumption can be calculated by different time. Can be seen from Tab.2, the longer the sleep time, the longer controller can work. Moreover, the result showed that the 1200mAh battery was sufficient to maintain an irrigation quarter. The performance of the irrigation controller was analyzed in terms of satisfactory operation of the controller hardware and software. The irrigation controller performance was considered satisfactory and two batteries would be sufficient to power the irrigation controller during the normal irrigation season. If the sleep time was set at 10min or more, the controller proved to be effective for the actual application in the root zone.
5 Conclusion A Wireless Intelligent Valve Controller for wireless integrated irrigation control system was developed and tested. The controller proved to be reliable, affordable, and effective in practice without hard-wire connections. The wireless intelligent valve controller with control unit, combined with low-power microprocessor chip and a sound external circuit, powered by battery, received control command from remote control center, executed the tasks, such as information acquisition, remote control, parameter setting, state feedback, while the task of valve control must be driven though the relay boost driver unit. The wireless transceiver capabilities reflected in the wireless communication unit. The valve control can be widely used in different irrigation regions.
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Wireless intelligent valve controller fully considers the energy in application field, setting the collection/control frequency in accordance with the user demands. Increasing solar power charge unit to controller to ensure the power supply is the next research work. Wireless intelligent valve controller is simple construction, easy maintenance, low cost and has good application prospects. Acknowledgements. This research is supported by National Science and Technology Support Programmed (2008BAB38B03-03), Land Consolidation and Rehabilitation Center of Ministry of Land Resources and Beijing UNISM Technology Co., Ltd for their Technical Support. The authors would like to thank all the members of EU-China Center for Information and Communication Technologies for their assistance.
References 1. Miranda, F.R., Yoder, R.E., Wilkerson, J.B., Odhiambo, L.O.: An autonomous controller for site-specific management of fixed irrigation systems. Computers and Electronics in Agriculture 48, 183–197 (2005) 2. Mareels, I., Weyer, E., Ooi, S.K., Cantoni, M., Li, Y., Nair, G.: Systems engineering for irrigation systems successes and challenges. Annual Reviews in Control 29, 191–204 (2005) 3. Cardenas-Lailhacar, B., Dukes, M.D.: Precision of soil moisture sensor irrigation controllers under field conditions. Agricultural Water Management 97, 666–672 (2010) 4. Davis, S.L., Dukes, M.D., Miller, G.L.: Landscape irrigation by evapotranspiration-based irrigation controllers under dry conditions in Southwest Florida. Agricultural Water Management 96, 1828–1836 (2009) 5. McCready, M.S., Dukes, M.D., Miller, G.L.: Water conservation potential of smart irrigation controllers on St. Augustinegrass. Agricultural Water Management 96, 1623–1632 (2009) 6. Blonquist Jr., J.M., Jones, S.B., Robinson, D.A.: Precise irrigation scheduling for turf grass using a subsurface electromagnetic soil moisture sensor. Agricultural Water Management 84, 153–165 (2006) 7. Wei, Z., He, Y., Qiu, Z., et al.: Design of precision irrigation system based on wireless sensor network and fuzzy control. Transactions of the CSAE 25(Supp. 2), 7–12 (2009) (in Chinese) 8. Zhang, J., Chen, J., Hu, J., Zhao, Y.: Control system of urban green land precision irrigation based on GPRS / SMS and μC / OS embedded technology. Agricultural Engineering (09), 1–6 (2009) (in Chinese) 9. Gao, F., Yu, L., Zhang, W., Xu, Q., Yu, L.: Research and design of crop water status monitoring system based on wireless sensor networks. Agricultural Engineering (02), 107–112 (2009) (in Chinese) 10. Shen, C., Zheng, W., Sun, G., Yan, H., Xing, Z.: Development and Application of Low Power Wireless DC Solenoid Valve and Controlling Module. Agricultural Machinery 40(z1) (2009) (in Chinese) 11. Liu, H., Wang, M., Wang, Y., Ma, D., Li, H.: Development of farmland soil moisture and temperature monitoring system based on wireless sensor network. Jilin University (Engineering Science) (03), 604–608 (2008) (in Chinese)
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12. Kuang, Q., Zhao, Y., Bai, C.: Automatic monitor and control system of water saving irrigation. Agricultural Engineering (06), 136–139 (2007) (in Chinese) 13. Yang Genghuang, Guo Kairong, Ya-Weili, A new automation device for irrigation based on GSM network. Journal of Shenyang Agricultural University, 2005 - 12, 36 (6): 753 - 755, (in Chinese)
Evaluation of the Rural Informatization Level in Central China Based on Catastrophe Progression Method Lingxian Zhang, Xue Liu, Zetian Fu, and Daoliang Li* College of Information & Electrical Engineering, China Agricultural University, P.O. Box 209, 17 Qinghua East Road, Haidian District, Beijing, China [email protected], [email protected]
Abstract. This paper developed a methodology based on the catastrophe theory for estimating the rural informatization level in central China, and took evaluation of the rural informatization level among the six provinces of central China as an example to test the effectiveness of the method. Taking data from reference and constructing the hierarchy based on catastrophe progression method, it was calculated the scores of rural informatization level among the six provinces of central China using normalizing formula. The results are found to be coincident with practical situation, so it proves the catastrophe progression method works well. Keywords: rural informatization, level, evaluation, Catastrophe Progression Method, the central China.
1 Introduction As rural informatization is an important component of the national informatization development process, it is the basis for decision-making to make an objective assessment and analysis to national and regional level of development of rural informatization. There have many methods for multiple object comprehensive evaluation [1-4], such as factor analysis, RITE’s Index of Information, Information Society Index(ISI), UN’s Information Utilization Potentials, fuzzy evaluation, analytic hierarchy process [5] and so on. But some methods have defects with more subjectivity on weight decision or too complex processes in calculation. The paper introduces the main steps and idea of a method using catastrophe theory (CT), namely, called catastrophe progression method (CPM). Its characteristic is combining catastrophe theory with fuzzy mathematics, and only considers the relative importance of the indices, so the method avoids the subjectivity for weight decision. Catastrophe progression method also has advantages in solving problems of fuzzy multiple object decision because the catastrophe progression is a multidimensional fuzzy membership function. With these characteristics, the method is easier and the results are more precise [6]. *
Corresponding author. Tel.: +86 010 62736764; Fax: +86 010 62737741.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 672–679, 2011. © IFIP International Federation for Information Processing 2011
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2 The Evaluation Methodology for the Rural Informatization Level in Central China 2.1 Evaluation Index System of the Rural Informatization Level According as the composition project of national informatization index issued by Information & Industry Ministry of China on July 29th, 2001, taking the literature [7] from reference, this paper presents the evaluation index system for the rural informatization level in the central China, which includes the 5 categories (secondary indices) of the Economic strength, Information infrastructure, Information terminal equipment, Human resource and Information utilization, and 14 tertiary indices (Table 1). Table 1. Evaluation index system for the rural informatization level in the central China Evaluation objective
Category
Indices GDP per capita
Economic strength
informatization level of rural areas
Revenue per capita Per capita income of rural households Long-distance telephone exchange capacity Mobile switching capacity Information Length of long-distance optical infrastructure cable Internet broadband access ports Information terminal equipment
Index abbreviation GDP RP PI TC MC OC IB
Color television ownership
TO
Computer ownership
CO
Mobile telephone ownership Percentage of literate population to Human total aged 15 and over Number of rural information resource service employees Proportion of per capita information consumption Information expenditure of rural households utilization Proportion of Internet users in rural areas
MO LP IEm IEx IU
2.2 Assessment Model of the Rural Informatization Level Establishment of the hierarchical structural model. According to the regulation of indices grouping aforementioned, we constructed the catastrophe progression model for informatization level of rural areas in central China by four hierarchies, which was broken down in a manner as shown in Fig.1.
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GDP ( x11 ) Economic strength (B1)
RP ( x12 )
PI ( x13 )
Cusp
Information infrastructure (C1) Information terminal equipment (C2)
Information hardware (B2)
TC ( X21 )
MC ( X22 ) Butterfly OC ( X23 )
IB ( X24 ) TO ( X31 ) Swallowtail CO ( X32 )
Human resource (B4)
Membership degree of rural informatization level in central China
Butterfly
Swallowtail
MO ( X33 )
Cusp
LP ( X41 )
Information utilization (B5)
IEm ( X42 )
Cusp
IEx ( X51 )
IU ( X52 )
Fig. 1. Catastrophe progression model for rural informatization level in the central China
Confirming the catastrophe type in every catastrophe subordinate system. Catastrophe theory analyses critical degenerate points of the potential function, where not just the first derivative, but one or more higher derivatives of the potential function are
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also zero. There are seven fundamental types of Catastrophe models presented, three types of which, such as elliptic umbilic catastrophe, hyperbolic umbilic catastrophe, and parabolic umbilic catastrophe, are under behavior variation of two dimension. Among seven fundamental types only four common catastrophe types are cusp catastrophe, swallowtail catastrophe and butterfly catastrophe, respectively, which potential functions are as follows [8]:
,
Fold catastrophe: f ( x) = x3 + ax . Cusp catastrophe: f ( x) = x 4 + ax 2 + bx . Swallowtail catastrophe: f (x ) =
1 5 1 3 1 2 x + ax + bx + cx . 5 3 2
1 1 1 1 Butterfly catastrophe: f (x) = x 6 + ax4 + bx3 + cx2 + dx . 6 4 3 2 Where f(x) is the potential function of the state variable x, and a, b, c and d are control variables of the state variable. In the catastrophe progression model for informatization level assessment of rural areas, the catastrophe type was confirmed in every evaluation index layer (see Fig.1). There were three catastrophe type, such as cusp catastrophe (one index divided into two sub-indices), swallowtail catastrophe (into three sub-indices) and butterfly catastrophe (into four sub-indices). Normalizing the control variables of the catastrophe model Standardizing data. The standardized data are in the value range of from 0 to1. Equation (1) is adopted if the index is positive, equation (2) is applied if negative. a) For The-Larger-The-Better indices, let
yij =
xij − xmin ( j ) xmax ( j) − xmin ( j)
xmin ( j ) < xij < xmax ( j )
(1)
xmin ( j ) < xij < xmax ( j )
(2)
b) For The-Smaller-The-Better indices, let
yij =
xmax ( j ) − xij xmax ( j ) − xmin ( j )
Where j is a sequence number for catastrophe subordinate systems, i is a serial number of control variables in a catastrophe subordinate system;
xij is merely the values
of x corresponding to control variables in a hierarchy of i and j, respectively;
yij is
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only the standard transformation values of xij ; xmin ( j ) , xmax ( j ) are lower limit or upper limit values of x corresponding to control variables in a catastrophe subordinate system, respectively. Formulas for normalization of control variables. For the cusp, fold, swallowtail, and butterfly catastrophe system, the decomposition forms of the equation of the bifurcation point set and the normalization formulas are showed in Table 2. Table 2. Catastrophe models under behavior variation of one dimension Catastrophe type
Dimensions of control variation
Potential function
Bifurcation set
Fold
1
f x x 3 ax
a 3x 2
Cusp
2
f x x ax bx
a 6 x , b 8x
Swallowtail
Butterfly
4
f x
3
f x
4
2
2
1 5 1 x ax 3 5 3
1 bx 2 cx 2 1 6 1 1 x ax 4 bx 3 6 4 3
1 cx 2 dx 2
a
6 x , b
c
3x 4
2
Normalization formula
xa xa
3
3
8x ,
10 x 2 , b
20 x 3 ,
c
15 x , d
5
4
a , xb
xa
a , xb 4
xc
a
4x
xa xc
a
4
3
b 3
b,
c
a , xb
3
b,
c , xd
5
d
Principles of finding values of catastrophe subordinate functions. During the process of computation, we must follow two principles, i.e., a complementary and a non-complementary principle. The non-complementary principle means that the smallest of the state variable values corresponding to the control variables (xa, xb, xc and xd) is chosen as the state variable value of the whole system; However, the complementary principle implies x=(xa+xb+xc+xd)/4. Hierarchically doing the calculation in the same way, the value of the overall catastrophe subordinate function can be found [9].
3 Results and Discussion In the light of the evaluation methodology of rural informatization level aforementioned, the paper take evaluation of rural informatization level among the six provinces of central China as an example to test the effectiveness of the Catastrophe Progression Method and referred to interrelated data on Beijing and nationally average in the mainland of China. The central China is a central region, including six provinces, such as Shanxi, Anhui, Jiangxi, Henan, Hubei, and Hunan (see Fig.2), with total population of 360 million people in the end of 2008. It plays an important role on the pattern of economic and social development in China, which land area is 1.03 million square kilometers, Gross Regional Product of which reached 6.3188 trillion RMB Yuan in 2008, accounting for 19.3% of GDP in China.
,
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Fig. 2. Space diagram of the six provinces of central China
Taking data from reference [7], the region′s overall number of communication facilities was in place of four indices of information infrastructure in rural areas, telecommunications and other information transfer service employees in place of indices about the number of rural information service personnel, the proportion of local comprehensive internet users in place of the proportion of internet users in rural areas. Table 3 showed some practical index values of the rural informatization level among the six provinces of central in 2006, Table 4 showed the standardized data of practical index values for the rural informatization level from the six provinces of central China transformed by equations (1) and (2). At the same time, the scores of rural informatization level among the six provinces of central China were calculated using normalizing formula (see Table 5). Table 3. Collected data from the six provinces of central China [7] Region x11
x12
x13 X21 X22 X23 X24
X31
X32
X33
X41
X42
X51
X52
Beijing 4.98 7066.08275 365 129 1788 21
133.2 36.1 104.3 95.5
37.6 1542.2 30.4
Shanxi 1.41 1729 3181 86.2 43.2 1445 4.4
98.4 1.38 72.1 95.6
9.8
564
11.3
Anhui 1.01 701 2969 78.5 23.7 1873 2.2
91.8 1.16 79.2 83.7
4.4
527.9
5.5
Jiangxi 1.08 704 3460108.0 40.3 1052 2.8
90.0 1.10 64.7 90.8
5.9
538.4
6.6
Henan 1.33 723 3261 62.4 31.3 1764 2.5
88.8 1.02 53.4 91.4
4.3
419.4
5.5
Hubei 1.33 836 3419 82.1 44.7 1234 3.9
92.1 2.33 57.3 90.2
8.6
538.4
9.3
Hunan 1.19 754 3390 73.4 31.7 1393 3.3
80.9 0.95 60.2 93.5
5.3
591.4
6.4
89.4
7.4
593.9 10.5
Nationally average 1.79 1417 3587106.8 47.3 752 5.02
Data source: Huang, 2009.
2.7
62.5 90.69
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Region
x11
x12
x13
X21
X22
X23
X24
X31
X32
X33
X41
X42
X51
X52
Beijing 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 Shanxi
0.101 0.162 0.040 0.079 0.185 0.669 0.117 0.335 0.012 0.367 1.008 0.165 0.129 0.233
Anhui
0.000 0.000 0.000 0.053 0.000 1.082 0.000 0.208 0.006 0.507 0.000 0.003 0.097 0.000
Jiangxi 0.018 0.000 0.093 0.151 0.158 0.290 0.032 0.174 0.004 0.222 0.602 0.048 0.106 0.044 Henan
0.081 0.003 0.055 0.000 0.072 0.977 0.016 0.151 0.002 0.000 0.653 0.000 0.000 0.000
Hubei
0.081 0.021 0.085 0.065 0.199 0.465 0.090 0.214 0.039 0.077 0.551 0.129 0.106 0.153
Hunan 0.045 0.008 0.079 0.036 0.076 0.619 0.059 0.000 0.000 0.134 0.831 0.030 0.153 0.036 Nationally 0.196 0.112 0.116 0.147 0.224 0.000 0.150 0.163 0.050 0.179 0.592 0.093 0.155 0.201 average
Table 5 showed catastrophe progression values of the rural informatization level among the six provinces in central China. From Table 5, catastrophe progression values (CPV) of the rural informatization level averaged 0.793 in the mainland of China; CPV is bigger in only one province of the six provinces in the central China than nationally average in the mainland of China. CPV is larger in Beijing Municipality than in each region of the six provinces in the central China. Among the six provinces in the central China, CPV of Shanxi province is first with 0.800, Hubei province second with 0.773, Jiangxi province third with 0.722, Hunan province fourth with 0.714, Henan province and Anhui province least with 0.354 and 0.222, respectively. The results are found to be coincident with practical situation. Table 5. The evaluation result by CPM
Beijing
Catastrophe progression values 1.000
Shanxi Anhui
0.800 0.222
1 6
Jiangxi
0.722
3
Region
No.
Region Henan Hubei Hunan Nationally average
Catastrophe progression values 0.354 0.773 0.714
No. 5 2 4
0.793
4 Conclusion The paper take evaluation of rural informatization level among the six provinces of central China as an example to verify the effectiveness of the method. Based on catastrophe progression method, it calculated the scores of rural informatization level among the six provinces of central China using normalizing formula. The results are found to be coincident with practical situation, so it proves the catastrophe progression method works well.
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From the calculation process, it was found that catastrophe progression method works simply and quickly. So the method was proved feasible in practice and provides us a new way in solving the problems of multiple objects comprehensive evaluation [6]. Acknowledgments. Thanks are due to National Science & Technology Support Program (2008BAB38B06) and Project from the Ministry of Agriculture of China (The twelfth five-year plan of agriculture and rural informatization development in China (2011-2015)) for financial support.
References 1. Bazewicz, M.: Information systems paradigms for design, engineering and education, Cybernetics and Systems 1994. In: Proceedings of the Twelfth European Meeting on Cybernetics and Systems Research, vol. 1, pp. 391–398 (1994) 2. Yu, E.J., Leem, C.S., Park, S.-K., Kim, B.W.: An integrated evaluation system for personal informatization levels and their maturity measuement: Korean motors company case. In: Gervasi, O., Gavrilova, M.L., Kumar, V., Laganá, A., Lee, H.P., Mun, Y., Taniar, D., Tan, C.J.K. (eds.) ICCSA 2005. LNCS, vol. 3482, pp. 1306–1315. Springer, Heidelberg (2005) 3. Chang, M.S., Guo, W., Yang, L.: Research on integrated information system of regional enterprise informationization market. Computer Integrated Manufacturing Systems 9(1), 6– 10 (2003) 4. Hu, J., Yan, Y., Lu, J.P., Zhao, C.H.: A study on the informatization evaluation index system of manufacturing enterprises and evaluation standard. Modular Machine Tool & Automatic Manufacturing Technique 12, 97–99 (2005) 5. Zhang, L.X., Wen, H.J., Li, D.L., Fu, Z.T., Cui, S.: E-learning adoption intention and its key influence factors based on innovation adoption theory. Mathematical and Computer Modelling 51(11-12), 1428–1432 (2010) 6. Li, Y., Chen, X.H., Zhang, P.F.: Application of catastrophe progression method to evaluation of regional ecosystem health. China Population Resources and Environment 17(3), 50– 54 (2007) (in Chinese) 7. Huang, Z.W.: Study on analysis evaluation for China’s rural informatization in six provinces of the central. Modern Agricultural Science and Technology 15, 370–373 (2009) (in Chinese) 8. Huang, Y.L.: Application of catastrophe progression method to sustainable usage of water resource. Arid Environmental Monitoring 15(3), 167–170 (2001) (in Chinese) 9. Zhang, T.J., Ren, S.X., Li, S.G., Zhang, T.C., Xu, H.J.: Application of the catastrophe progression method in predicting coal and gas outburst. Mining Science and Technology 19(4), 430–434 (2009)
GIS-Based Evaluation on the Eco-Demonstration Construction in China Lingxian Zhang, Juncheng Ma, Daoliang Li, and Zetian Fu* College of Information & Electrical Engineering, China Agricultural University, P.O. Box 209, 17 Qinghua East Road, Haidian District, Beijing, China [email protected], [email protected]
Abstract. The ecological construction for demonstration area is an idealized model for the establishment of rural sustainable development in the county-scale. This paper presents a GIS-based evaluation system of ecological construction for demonstration area. It includes an index system with the 4 secondary indices and 24 factor indices, and a method of ecological construction for demonstration area utilizing multi-attribute decision models of AHPCI method for comprehensive performance assessment. Taking Xinyang city of Henan province in China as a case study, the comprehensive assessment result were found to be coincident with practical situation, so it proves that the GIS-based evaluation system was fit for county-level ecological construction assessment for demonstration area as a beneficial reference framework elsewhere. Keywords: Evaluation system, Eco-demonstration construction, AHPCI, Sustainable development.
1 Introduction Since United Nations Conference on Environment and Development (UNCED) in 1990s, the sustainable development concept has gradually been accepted all over the world with respect to almost all aspects of human development [1]. The ecodemonstration area is regarded as an important way to maintain regional sustainable development in many countries. The ecological construction for demonstration area is an idealized model for the establishment of rural sustainable development in the county-scale. Eco-demonstration area is a compound ecosystem of society, economy and nature, which is relatively independent and exoteric [2]. The eco-demonstration concept lies close to the UN Millennium Project [3] and aims at making a contribution to this programme. Eco-demonstration construction refers to the application of ecological principles to the development of human ecosystems in order to achieve sustainability. It consists of three components: ecological engineering, ecological institutional reestablishment and ecological cultural remolding. Since 1980, a vigorous campaign for the ecological construction for demonstration area has appeared in China, and many eco-polis, eco-counties, eco-villages as well as eco-families had sprung up all over the country [4]. In 1996, the Ministry of *
Corresponding author. Tel.: +86 010 62736323; Fax: +86 010 62737741.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 680–690, 2011. © IFIP International Federation for Information Processing 2011
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Environmental Protection of China(MEPC) carried out the activities of the national creation of eco-demonstration area, and a lot of eco-demonstration areas had been created in our country, as not only promoted coordination of economy, society and environmental protection in pilot region but also have positive effect on surrounding areas [5]. The evaluation of sustainable development for eco-demonstration area is the base of perfecting the sustainable development theory for eco-demonstration area and guiding its construction [6]. To promote the benign development of eco-demonstration area construction, this paper promoted an evaluation index system of eco-demonstration area construction based on criterion for eco-demonstration area construction issued by MEPC, and developed a GIS-based assessment model utilizing the Analytical Hierarchy Process (AHP) and Competitiveness Index (AHPCI) method.
2 Evaluation Methodology for Intra-county Eco-Demonstration Construction 2.1 Evaluation Index System of Intra-county Eco-Demonstration Construction Taking the criterion of the national creation of eco-demonstration area and goal of eco-demonstration construction into account, the paper presented a set of quantitative and hierarchical index system with the 4 secondary indices, and 24 factor indices by integrating the assessment goal and the standards of eco-demonstration construction announced by MEPC according to the design principles and requirements of the index system (Table 1). Table 1. Index systems and its standard for the intra-county eco-demonstration construction Primary Second index Third index index
Name
Comprehensive Level of sustainable development for Eco-demonstration
GDP per capita Disposable income of urban residents Per capita annual net income of peasantry Unit GDP energy consumption(ton/ten thousand) Unit GDP water consumption meter/ten Economic (cubic thousand) structure Proportion of investment in environment protection in GDP (%) Water productivity (kilogram/cubic meter) National income
Economic development
Fourth index
Reference value Code Upper Lower limit limit Q11 Q12 Q13
>4000
1600
Q21
1.3-1.4 1.5-1.6
Q22
<200
<600
Q23
1
1.2
Q24
>1.5
0.9
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Table 1. (continued)
Social progress
The natural population growth rate (%) Eligibility rate of urban drinking water (%) Life quality City gasification efficiency Coverage rate of sanitary toilets in rural areas (%) Harmony
Q31
Local criterion
Q32
≥90
≥60
Q33
>90
>35
Q34
>70
>35
Urbanization (%)
Q41
GDP per capita
Q42
Disposable income of urban residents
Q51 National criterion
Resource Per capita annual net utilization income of peasantry Unit GDP energy consumption(ton/ten thousand) Unit GDP water3 consumption(m /ten Ecological thousand) construction Proportion of investment in environment protection Environment in GDP (%) protection Water productivity (kg/m3) The natural population growth rate (%) Comprehensive utilization of straw Manure disposal rate (%) Environment protection Amount of fertilizer application (equivalent pure kg/ha) Amount of pesticide application (equivalent pure, kg/ha)
,
Q52
>10
>7
Q53
100
>80
Q61
>10
>10
Q62
>90
>80
Q63
>80
>60
Q64
>50
>30
Q71
>90
>70
Q72
100
80
Q73
<280
<280
Q74
<3.0
<3.0
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In the index system, the comprehensive level of sustainable development for ecodemonstration areas is regarded as the general goal. In order to realize the regional sustainable development, the basis of resource and environment that support the development of social and economy is needed. Therefore, this paper divided the general goal into 4 sub-goals of economic development, social progress, ecological construction and environmental protection, which were further divided into the third level indices of national income, economic structure, quality of life, harmony, resource utilization, environmental management and protection. According to the requirements and principles, the general goal was divided into 24 indices. 2.2 Assessment Model of the Intra-county Eco-Demonstration Construction Constructing the hierarchical structural model. Following AHP, the level of sustainable development for eco-demonstration area is divided into three hierarchical structural levels from the bottom to the top. In the top is the general goal of the hierarchical structure, namely the overall objective layer with only one key element for the comprehensive level of sustainable development for eco-demonstration. The intermediate level is the criterion layer with several intermediate elements, such as economic development, social progress, ecological construction and environmental protection. The bottom, namely influence factors layer, is composed of various kinds of factors in evaluation system. There exist specific logic relationships between neighbor layers. The hierarchical structural model for evaluating the ecodemonstration construction was showed in Fig.1. Presenting the comparison matrix by layers. The comparison matrix below provides a measure of the weight factors for decision making, which denotes the relative importance of the element of each layer shown in the hierarchical structural model. Often from top to bottom, the comparison matrix could be established with one element of the above layer pairing and comparing with all the elements of the neighboring below layer according to the relationship between the elements or the layers. Between layer A and B showed in Fig.1, the comparison matrix of A–B layer can be established (Table 2), whose elements are evaluated using a 9-point scale. The comparison matrix is a square matrix as A = (Bij ) n × n , and:
Bij >0;
Bij =1 Bji;
Bii = Bjj =1
(1)
Where Bij is the pairing comparison of element i with element j in the B layer of the A-B comparison matrix. Similarly, the comparison matrix of B–C and C–Q layers can be obtained in the same way used in forming the comparison matrix of A–B layers. Data on paired comparison matrices were collected from reviewers. Scores of Bij were estimated on the average by experts. The participating decision makers provided paired comparisons for each level of the hierarchy in order to obtain the weight factors of each element on that level, and with respect to one element in the next higher level [7].
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Attributes (B, C)
Factor alternatives (Q) Q11
Objective (A)
Society Progress(B2) Ecologicalconstructione(B3) Environment Protection(B4)
Comprehensive level of sustainable development for Eco-demonstrationareas (A)
Economic Development(B1)
C1
Q12 Q13 Q21
C2
Q22 Q23 Q24 Q31
C3
Q32 Q33 Q34
C4
Q41 Q42 Q51
C5
Q52 Q53 Q61
C6
Q62 Q63 Q64 Q71 Q72 Q73 Q74
Fig. 1. Hierarchical structural model for evaluating the eco-demonstration construction
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Table 2. A-B comparison matrix
A
B1
B2
B3
B4
B1
B11
B12
B13
B14
B2
B21
B 22
B 23
B 24
B3
B31
B32
B33
B34
B4
B41
B42
B43
B 44
2.3 Calculation of Comprehensive Level of Sustainable Development for Eco-Demonstration In ecological evaluation for eco-demonstration construction based on rural sustainable development, we adopt the evaluation standard of the comprehensive level of sustainable development (Table 1). In order to better carry out analysis and comparison, this paper has adopted a methodology of the comprehensive evaluation index to calculate the weight of every index to comprehensive level of sustainable development for an eco-demonstration area. Each index is translated into a dimensionless index score such as GDP per capita, amount of fertilizer application etc.; then weighted in order produce a measure of the comprehensive level of sustainable development for the eco-demonstration area. The specific methods of evaluation are as follows: a) For the positive index, let x ij − x min ( j ) xmin ( j ) < xij < xmax( j ) (2) Q ij = x max ( j ) − x min ( j ) a) For the negative index, let Q ij =
x max ( j ) − x ij x max ( j ) − x min ( j )
xmin( j ) < xij < xmax( j )
(3)
Where j is a sequence number for evaluation subordinate systems, i is a serial number of indices in a subordinate system;
xij is the original values of indices in a hierarchy
of i and j, respectively; Qij is only the standard transformation values of xij ; xmin ( j ) , xmax ( j ) are lower limit or upper limit values of indices in a evaluation subordinate system, respectively. Calculating by weight in term and layer from the beginning of the specific index, we obtained the overall value of the comprehensive level of sustainable development. This can be expressed as follows: CI =
n
m
∑ W (∑ W i=1
i
j= 1
ij
Q ij )
(4)
Where CI is competitiveness index, representing the comprehensive level of sustainable development for eco-demonstration areas; n is the number the component factors of the comprehensive level of sustainable development for eco-demonstration
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areas, here n for 4; m represents sub-factor in number i component factor of the comprehensive level of sustainable development for eco-demonstration areas; Q ij is the standardized value of number j sub-factor of number i component factor; Wij is the weight of number j sub-factor of number i component factor. By taking various statistical yearbooks, bulletins and other relative data, and national and international corresponding index standards into account, we designed a four-stage classification standard with the critical value and values of upper and lower limit of the CI of the comprehensive level of sustainable development for ecodemonstration areas (Table 3). Table 3. Classification standard of the comprehensive level evaluation [8] Level
Qualitative evaluation of comprehensive level of sustainable development Very good
Critical value
Ⅰ Ⅱ Ⅲ Ⅳ
> 0.75 0.50-0.75
Better
0.25-0.49
General
< 0.25
Poor
2.4 Design of GIS-Based Evaluation System According to the evaluation algorithm of the comprehensive level of sustainable development for eco-demonstration areas aforementioned, this paper put forward a GIS-based evaluation system of ecological construction for demonstration area, which was designed three modules, including GIS operating, thematic evaluation and auxiliary module, in virtue of the geographic information system technology (Fig.2).
Auxiliary function
Evaluation system for eco-deminstration construction
Spatial database
Printout picture
File management
Thematic evaluation
Drawingofthematicpictur
Thematic evaluation
Data demonsionless
Weight calculation
Data association
Data query and modify
Attribute transforming
Attribute importing
Zoom in and zoom out
Roaming map and eagle
Spatial query
Attribute database
GIS operating
Attribute database
Fig. 2. Function frame of GIS-based evaluation system
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3 Results and Discussion 3.1 General Situation of Study Area This paper took evaluation of the sustainable development level for ecodemonstration area at Xinyang city of Henan province in China as an example to test the effectiveness of the AHPCI method. Xinyang city is located in south part of Henan province, P.R China. It consists of 8 counties and 2 districts, with the population of 7.8 million, the total area of 18000 2 km . Only one of Xinyang city, Luoshan county, was identified as the national ecodemonstration area in 2004. By comparing CI of the 9 counties at Xinyang city (two districts as one), we could conveniently analyze the construction performance of ecodemonstration area at Luoshan county, and provided a beneficial reference framework for the eco-demonstration construction elsewhere. 3.2 Weight Calculation and Consistency Test From Fig.1, the comparison matrix of A–B layer would be considered consistent (and accepted) with a CR (consistency ratio) lower than 0.1. Similarly, we could obtain the weight of the evaluation attribute layer C1–C2 to B1, C3–C4 to B2, C5–C6 to B3; and the weight of the evaluation index layer Q11–Q13 to C1, Q21–Q24 to C2, Q31–Q34 to C3, Q41–Q42 to C4, Q51–Q53 to C5, Q61–Q64 to C6, Q71–Q74 to B4 (wholly passed the consistency test, and accepted) (Tables 4 and 5). Table 4. Single ranking of the assessment factors Index
B1
B2
B3
B4
0.455
0.263
0.141
0.141
C1
0.200
C2
0.800
Single ranking 0.091 0.364
C3
0.750
C4
0.250
0.197 0.066
C5
0.250
0.035
C6
0.750
0.106
From Table 4, we could find that in the second layer, economic development had the maximum weight (0.455), while in the third layer, C2 (economic structure) had the maximum weight (0.364). Table 5 showed obviously the weight of 24 evaluation indices of the fourth layer to the general objective of the comprehensive level of sustainable development for ecodemonstration, of which unit GDP energy consumption (0.105) reached the largest influence and the second was the proportion of poor people (0.098), while the least influence was obtained by tourist district environmental compliance rate (0.004).
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C1
C2
C3
C4
C5
C6
B4
0.091 0.539 0.164 0.297
0.364
0.197
0.066
0.035
0.106
0.141
Total ranking
0.081 0.428 0.301 0.189
0.049 0.015 0.027 0.105 0.092 0.060 0.039 0.086 0.070 0.034 0.014 0.049 0.098 0.021 0.010 0.004 0.037 0.025 0.015 0.009 0.011 0.060 0.042 0.027
0.445 0.283 0.165 0.107 0.589 0.193 0.149 0.069 0.250 0.750 0.608 0.272 0.12 0.542 0.233 0.14 0.085
3.3 Intra-county Comprehensive Level of Sustainable Development for Eco-Demonstration Fig.3 and Fig.4 showed the intra-county comprehensive level of sustainable development for eco-demonstration at Xinyang. Xinyang district gets the maximum (0.8757), and 0.9 0.85 0.8 0.75 0.7 0.65 i an an an ng an an ng in sh sh xi hu he xi sh ya ib Gu ng Xi gc gc in uo in ua a n n X L X H a a Gu Hu Sh
Fig. 3. Intra-county comprehensive level at Xinyang
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Fig. 4. Thematic evaluation intra-county comprehensive level at Xinyang
Shangcheng ranks the second (0.8149) followed by Xinxian (0.8024), Huangchuan (0.7928), Gushi (0.7846), Luoshan (0.778), Guangshan (0.769), and Xixian (0.7388, minimum). The comprehensive level of Huangchuan, Shangcheng, Guangshan, Xinxian, Luoshan, Xinyang and Gushi are at the level I of the classification standard while Huaibin and Xixian reach at the level II, as is found to be coincident with practical situation.
4 Conclusion Analyzing the literature and combining with the reality, this paper sets 24 evaluation indices according to the principles of evaluation and conditions specified, and establishes the evaluation system of eco-demonstration construction by the AHPCI method as well as develops an evaluation system of intra-county eco-demonstration construction. The results show that the model of evaluation system of eco-demonstration area reflects the comprehensive level of the 9 counties in Xinyang city and corresponds with the reality, which offers the basis to construction of eco-demonstration sustainable development and contributes to the construction of national ecodemonstration. The evaluation system of eco-demonstration sustainable development is proved to be reliable, which presents a tool for the evaluation of eco-demonstration sustainable development. Acknowledgement. Thanks are due to National Science & Technology Support Program (2008BAB38B06) for financial support.
References 1. Liang, B.P., Huang, F., Chen, B., Li, H.J.: Comprehensive Evaluation of the Sustainable Development of an Ecological Demonstration District. Bulletin of Soil and Water Conservation 24(1), 74–78 (2004) (in Chinese)
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2. Yang, C.F.: Building High Quality Ecological Demonstration Areas. Environmental Protection 1, 16–19 (2000) (in Chinese) 3. UN Millennium Project: Investing in Development: A Practical Plan to Achieve the Millennium Development Goals. Earthscan, London (2005) 4. Hu, D., Wang, R.S.: Exploring eco-construction for local sustainability: An eco-village case study in China. Ecological Engineering 11, 167–176 (1998) (in Chinese) 5. Yan, H., Zhang, T., Li, D.C., Ma, X.F., Ren, F., Zhao, W.J.: Evaluation Index System and Development Sustainability of Nongan County Ecology Demonstration Zone in Jilin Province. Journal of Jilin University (Earth Science Edition) 36, 95–99 (2006) (in Chinese) 6. Chen, H., Kang, M.Y., Zhao, Y.L., Liang, X.Y., Fan, Y.D.: Degree and Its Application of Sustainable Development of Ecological Demonstration Areas. Bulletin of Soil and Water Conservation 23(4), 61–65 (2003) (in Chinese) 7. Saaty, T.L.: Theory and applications of the analytic network process. RWS Publications, Pittsburgh (2005) 8. Li, Z.W., Zeng, G.M., Zhang, H., Yang, B., Jiao, S.: The integrated eco-environment assessment of the red soil hilly region based on GIS—A case study in Changsha City, China. Ecological modelling 202, 540–546 (2007)
Modeling and Analysis of Pollution-Free Agricultural Regulatory Based on Petri-Net Fang Wang, Qingling Duan*, Lingzi Zhang, and Guo Li College of Information and Electrical Engineering, China Agricultural University, Beijing, P.R. China 100083 [email protected]
Abstract. To carry out pollution-free agricultural products certification work is the important issue of people's daily lives. It is of great significance to construct the pollution-free agricultural regulatory system (PFARS) and achieve the office automation of the certification business. However, the PFARS contains much more steps in dispersion areas that it is very complex for business processes of E-PFAPC. In this paper, we not only provide the method of modeling the PFARS with Petri Net, but also provide the improved method to analysis the Performance of the constructed workflow model. The model for the PFARS provides a more simply process management than original work method. The provided workflow model analysis method can effectively verify the performance of building model. The results show that the PFARS system constructed by the workflow model can implement the business run automatically and own prefect performance. Keywords: workflow, pollution-free agricultural products, Petri net, work flow model, equivalent simplification, model performance.
1 Introduction Pollution-free agricultural products is the production that area, production process and product quality meet the national requirements of the relevant standards, Obtain a certificate and allow use the sign of pollution-free agricultural products [1]. Currently, the pollution-free agricultural products certification used in turn by the county, Agency-level work, provincial, sub-centers, the center of Ministry, and all other working bodies for approval step by step. But the information and instruments which used during the Certification at all levels of agency transfer by Postal service. This manual method is not only cost a lot of manpower, financial resources but also time. And can not do government affairs. Therefore, the design and development of electronic control systems is the trend of pollution-free agricultural products. One of the *
Corresponding author.
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key technologies to achieve the system is how to achieve pollution-free agricultural systems certification information automatable transfer during at all level of work agencies. The workflow technology leaded into the PFARS can solve the problems. Workflow technology according to the system real operational rules can make certified information fully or partially run automatically, in order to make the documents, information or tasks in business processing can automatic transfer and implement [2]. Model is the most important elements to determine the quality of workflow system. In this paper, we use the Petri Net which has a strict mathematical basis for pollution-free agricultural products regulation system workflow model to described certification business behavior, and an improved model method to verify the performance of the model.
2 Pollution-Free Agricultural Regulatory System Modeling 2.1 Petri net Technology and Work Flow Model Petri net invented by Carl • A • Petri in the 1960s [3], is a parallel system of discrete mathematics, suitable for describing asynchronous, concurrent computer system model. Petri nets can be graphically described the workflow, and own standard, clear and rich analysis techniques, to avoid ambiguity, uncertainty and contradiction. This method is one of the most common methods to construct the workflow model. Petri net is a two-way map that consisted by Place, Transition and the relation between them. Definition 1: A Petri net is a necessary and sufficient conditions to satisfy the following triple N = (P, T, F) [3]. (1) P ∪ T ≠ ∅ (Net of non empty); (2) P ∩ T = ∅ (Duality); (3)
F ∈ ( P × T ) ∪ (T × P ) (Flow relation only between the Place and Transition);
(4)
dom( F ) ∪ cod ( F ) = P ∪ T (Not isolated elements). Where dom(F), cod(F),
respectively on behalf of the domain and range. The structure of a Petri net elements include: place, transition and the arc. Place used to describe the possible local state (condition or status). Transition describes the events which modified state of the system. Arc is the relationship between place and transitions.
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Workflow model is the basis for workflow management systems. Workflow model the abstract and refine of the actual business processes, is the idea of workflow and workflow terms of the business process description and modeling results [4]. Workflow model includes all information which can execute by workflow engine, the information contains the condition to start or end a business process, the flow relation of the control data, Participants, organization, data, the application may be invoked, and all definition data which relevant to workflow. Workflow model consisted by two basic elements there are nodes and connecting, which is defined as a directed graph W ∈ {N , L} , N is the node set, L is the set of arc connections between nodes. In workflow model node stands for all activities, which refers to the general work unit. Each activity is independence and has its own properties. Examples of activities are task, for different process instance, the same activities may have different tasks. In the design of pollution-free agricultural products certification business workflow model is not only to describe the workflow process model, but also describe the certification body of the organization model, resource model, and provide information related to the definition of workflow data to make it a complete, multi-view of the model [5]. Process models are referenced by organized model, workflow relevant data and resource model. Workflow relevant data to support process model, organization model and resource model. The relationship between system models as shown in Figure 1:
Fig. 1. Certified pollution control system model diagram
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2.2 The Pollution-Free Agricultural Products Certification Net Model In system, organizational model consists of five elements: "staff", "role", "post”, “department" and "working group." The relationship of the Organizational model shown in Figure 2:
Fig. 2. Organization Model Entity Relationship Diagram
(1) Staff: Staff is the basic elements of the model which directly attributable to a certain department or working group. Each officer can own different role according his responsibilities or positions, and each role also corresponds to one or more human. (2) Department: is set for functions. In general, department is a agency which has the same location, goal and task. In addition to personnel other than, the other entities in system is a sub-level tree structure layer by layer. (3) Position: according to different responsibility in the sector to division different positions. Positions have the relationship formed between the upper and lower levels, staff responsible for the responsibilities of the position. (4) Role: is process-oriented and established based by the division of tasks in the system. Only with the role of staff have the appropriate permissions to operate. (5) Working Group: In order to adapt change or other tempt need, human in different departments and different roles can be organized dynamically. The Working Group was established for the process, reflecting the traditional function-oriented organization. The work organizations of the Pollution-free agricultural regulatory system are all over the country. As shown in Figure 3:
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Fig. 3. System of work organization
In the pollution-free agricultural regulatory systems, according to certified business processes into the role of the Ministry Center, the role of sub-central, the role of three types of local certification. 1 Central role of the Department
()
Fig. 4. Ministry of Agriculture, Centre for quality and safety role model
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(2)
Sub-center role of the Accreditation
Fig. 5. Role model professional certification sub-centers
(3)
Local certification role
The role of local certification
Provincial certification role
Role-level authentication
The role of county-level certification
Fig. 6. Local certification role model
Pollution-free agricultural regulatory systems certification business lines include: the first certification, Extended Authentication, normal replacement and portable review replacement. Each certified business requires approval through their respective links, materials review, site inspection, product inspection, origin detection, environmental testing and other relevant certification steps. Petri net based workflow process model is the abstract representation of the actual business processes, that is, the abstract representation of the business process. Based on the analysis of pollution-free agricultural products certification based on business processes, were established the first certified pollution, widening the certification, the normal review replacement, portable replacement and certificate review workflow process model change, where " " stands for Place, " " on behalf of Transition. To pollution-free for the first time the following certification business, for example, use of Petri net technology to build a workflow process model. First certification workflow process model shown in Figure 7:
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Fig. 7. Petri net-based breadth-first number of the first successful business model certification
The figure shows the first pollution-free agricultural regulatory systems certification business workflow model, taking into account the requirements model that will change in the original image and the place are carried out in accordance with the breadth-first order number, which used place T1, T2 , ... ..., said that change with the P1, P2, ... ... said. Figure in the place are the following meanings: T1 representation review audit, T2 that do not pass a formal examination, T3 that do not fill in the form of review of information through the comments, T4 confirmed that compliance approval, T5 that approval be returned to confirm compliance, T6 that fill approval to return to confirm the views of compliance information, T7, said approval to appoint inspectors, T8, said approval to appoint inspectors to return processing, T9 complete approval to appoint inspectors to return views of information, T10, said a comprehensive inspection approval, T11 comprehensive examination that approval be returned, T12 that a comprehensive examination of information processing views of complete return, T13 found that approval of origin, T14 found that approval of origin return processing, T15 found that approval of origin information filled returned opinions, T16 preliminary approval of products, T17 preliminary approval that products be returned, T18 Product preliminary approval, said approval of the views of complete return information, T19 review for approval of products, T20 review for approval of products be returned, T21 complete return of products to review for approval the views of information processing, T22 that generate batch processing, T23 that approval be returned batch generation , T24 fill in return for approval, said approval of the batch generation views information, T25 Final review of products, T26 Final review that product be returned, T27 Final return products that fill in the information processing view, T28 review that certificate number generated by, T29 reported that approval document signed audit through.
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3 Model Performance Analysis Traditional network based on Petri workflow process model built performance analysis method has exponential time complexity, based on pollution-free agricultural products certification process certified business link in task completion time of uncertainty, assumptions in the certification process to prepare an adequate prerequisite for certification material condition cases, pollution-free agricultural products certification based on drift-nets, stochastic Petri net equivalent simplification approach can introduce random trigger Petri-Net, we propose a linear time complexity of the average running time of workflow approximate performance analysis method, to make the capabilities of the model more precise analysis of time performance. In the continuous-time stochastic Petri net, a change can be implemented from time t to the implementation of the delay between the time seen as a continuous random variable, subject to A as a parameter of exponential distribution. A t is the average implementation rate of change that can be implemented in the case of the implementation unit of time the average number. The reciprocal of the average implementation rate of 1/2 as changes t0, is the average implementation delay or average service time. Combined with pollution-free agricultural products certification nets in the certification business for the execution time of the exponential distribution, the model of relief activities Ti, where (1 ≤ i ≤ n) associated with a rise rate λt , which λt is greater than 0, the real parameter, and A certified business for T to become enabled from time to time between it being raised as a continuous random variable Xi(to take a positive real number), and subject to a distribution function Ft ( x ) = { X t ≤ x} , the n random variables Xi (1 ≤ i ≤ n) as independent random variables. The distribution function can −λx be defined as an exponential distribution function: Ft ( x) = 1 − e (∀t ∈ T ) that the random variable Xt parameters obey the λt exponential distribution. According to the equivalent Petri Net reduction rules, pollution-free certification model simplified model shown in Figure 8:
Fig. 8. The Simplified workflow model of the first time Pollution-free certification business
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Theorem 1
:t
1
699
→ t2 → ⋅⋅⋅ti ⋅⋅⋅ → tn that certification part of the business activ-
ities of changes in ti, order execution, time to change the equivalent rescue execution time t:
1
λ
n
=∑ i =1
1
λi
.
Certification activities in the above definition changes t1, t2, ... ..., tn cause of the time independent random variables λ1 , λ1 , λ2 , ⋅⋅⋅, λn and follows a command parameter of Exponential distribution, n translation the execute time were to
1 1 1 , , ⋅⋅⋅, ; Use a
λ1 λ2
λn
time change t stands for n missions composed of the same subnet, the average service time T (
1
λ
).
According to the actual certification of pollution combined with expert opinion, statistics Figure 8 the various certification business for the time
1 tα ( ) = 20m ,
λ1
county-level review by the time the work of institution-level audit time
tα (
1
λ2
) = 35m , the provincial work plan review time tα (
of sub-centers
tα (
1
λ5
tα (
1
λ4
1
λ3
) = 40m , review time
) = 35m , the Department of center when the audit
) = 56m .
After simplifying the workflow process model, mainly composed by the sequence structure. Change t1, t3, t5, t7, t9, t11, t13, t15, t17, t19, constitute the order structure ( t1 → t3 → ⋅⋅⋅ti ⋅⋅⋅ → t19 ). Change t1 which constitute part of county-level certification; change t3, t5, t7, constitute part of prefecture-level certification; change t9, t11, constitute part of the provincial certification; changes t13 certification form part of sub-centers; changes t15, t17, t19, constitute the Department of Center Certification link; know that normally the average processing time is: 405m, largely for the certification of agricultural products now save time and money.
4 Conclusion This paper proposes a method to construct the first pollution-free agricultural products certification through use of Petri-net by analysis the actual requirements of the pollution-free agricultural regulatory operations and study the techniques of the workflow modeling. The model can clearly describe the certification business processes, lay a good foundation for the stable operation of the system.
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Moreover, to prove the performance of the workflow model, proposed the model reduction and stochastic Petri nets combination of authentication methods. By study the model verify that it is applied to the feasibility of pollution-free agricultural regulatory system can improve efficiency, government affairs, information sharing. The system is currently in trial operation phase, the performance is steady; apply to the country of five pollution-free agricultural regulatory agencies to jointly monitor the actual business process management needs.
References 1. Maaiguo, J., Luobin, F.: Pollution-free agricultural management and technology. China Agriculture Press, Beijing (2007) 2. Wang, G.: Workflow-based-e-government system and implementation of [MS Thesis]. Beijing Jiaotong University, Beijing (2007) 3. Yuan, C.: Petri Net Theory and Applications. Electronic Industry Press, Beijing (2005) 4. Jiang, C.: The behavior of Petri net theory and its applications. Higher Education Press, Beijing (2003) 5. van der Aalst, W.M.P., van Hee, K.M., van der Toom, R.A.: Component-based software architectures:a framework based on inheritance of behavion BETA Working Paper Series,WP 45, Eindhoven University ofTeclmology,Eindhoven (2000) 6. Dong, M., Chen, F.F.: Process modeling and analysis ofmanufacturing supply chain networks using object-oriented Petri nets. Robotics and Computer Integrated Manufaentring 17, 121–129 (2001) 7. Browning, T.R., Eppinger, S.D.: Modeling impacts ofprocess architecture on cost and schedule risk in product development. IEEE Transactions on Engineering Management 49, 428–442 (2002) 8. van der Aalst, W.M.P., van Hee, K.M., van der Toom, R.A.: Component-based software architectures:a framework based on inheritance of behavion BETA Working Paper Series,WP 45,Eindhoven University ofTeclmology, Eindhoven (2000) 9. Morelli, M., D’Eppinger, S.D., Gulati, R.K.: Predicting technical communication in product development organizations. IEEE Transactions on Engineering Management 42, 215–222 (1995) 10. Karsten, A., Schulz Orlowsk, E.: Facilitating cross—organisational workflows with a workflow view approach. Data&Knowledge Engineering 51, 109–147 (2004) 11. Workflow Management Coalition.Terminology and Glossary,[EB/OL].WFMC-TC 1011, pp. 3–8 (1999) 12. Workflow Management Coalition. Workflow Management Coalition Terminology and Glossary.Technical Report. WFMC-TC—l 0l 1. Workflow Management Coaltion, Brussels, pp. 34–46 (1996) 13. Hollingsworth, D.: The Workflow Reference Model. WfMC-TC – 1003, Issue, Brussels, pp. 201–210. Workflow Management Coalition, Brussels (2004)
An Online Image Segmentation Method for Foreign Fiber Detection in Lint Daohong Kan*, Daoliang Li, Wenzhu Yang, and Xin Zhang College of Information & Electrical Engineering, China Agricultural University, Beijing 100083, P.R. China [email protected]
Abstract. The image of lint containing foreign fiber features that the background (cotton fiber) is homogeneous and has a normal gray-level distribution; the object (foreign fiber) is smaller, darker than the background but its gray-level distributes is a wide range. In this paper, a Background Estimation Thresholding(BET) method is presented to segment the objects from such kind of images. The segmented objects will be used to determine the existence and measure the quantity of foreign fiber. The experimental results show that the BET is effective and fast, and can be used in the online foreign fiber inspection in volumes of lints. Keywords: Image segmentation, Thresholding, Cotton, Foreign fiber.
1 Introduction Machine vision is a technology adopted newly in cotton trade and textile industry to evaluate the cotton quality[1, 2]. The foreign fiber in lint such as plastic film, fabric patch, hemp rope, hair, polypropylene twine, feather, and etc., will seriously affect the quality of final cotton textile product and can be detected and measured by machine vision technology. China Agricultural University, together with China Cotton Machinery & Equipment Corporation are developing a Foreign Fiber Inspection System(FFIS) to measure the content of foreign fibers in lint, according to which to grade and price, so that the cotton farmers and traders will be more willing to keep the foreign fibers away. FFIS is composed of hardware subsystem and software system, and the hardware system mainly includes lint feeder, opener, scanner, collector and computer, as shown in Fig.1. Lint is fed into the opener by the feeder to generate a 2mm thick, uniform lint slice, in which foreign fiber will be exposed sufficiently and can be detected easily by the scanner. The lint slice is pushed by rollers into an iamging alleyway, which is made of glass with high transparence, and 400mm in width, 4mm in thickness. The lint slice is *
Corresponding author.
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imaged continuously by 2 scanners which are sensitive to visible light and ultraviolet radiation respectively. The image lines are assembled into frames and then transferred to the computer. Finally, the frames are processed online by the software subsystem.
Fig. 1. Scheme of FFIS
Image segmentation is a key step towards the foreign fiber inspection using machine vision technology. Mostly, the cotton fiber has high gray-level (bright) and the foreign fiber has low (dark), and thresholding is a reasonable choice for the segmentation of such kind of images. The thresholding method selects a gray-level T as the threshold based upon histogram (an approximation of gray-level probability distribution). If the gray-level g of a pixel is less than or equal to the T, the pixel will be marked as foreign fiber (object), otherwise as cotton fiber (background). How to select a threshold appropriately is critical to thresholding. The commonly used technique is to select the optimal threshold according to a Criterion Function(CF). Between-class variance[3] proposed by Otsu is a widely used CF, which is based upon histogram. Otsu method met difficulties when applied to most foreign fiber images, in which the objects are thin and small, and the histograms are unimodal, or in which the gray-levels of objects vary largely, and the histograms extend to the low gray-level side just like a long tail. Hou’s research[4] shows that large differences in class variances or class probabilities will result in threshold bias towards the component with larger class variance or larger class probability. Fig. 2 shows a lint image example with one hair, and its segmentation result by Otsu method.
An Online Image Segmentation Method for Foreign Fiber Detection in Lint
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(c)
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Fig. 2. (a) Lint containing a hair, (b) Segmentation by Otsu method, (c)(d) Histogram and its details at the bottom
There are many attempts to overcome the threshold bias of Otsu CF in the past decades, including modifing the Otsu CF or suggesting a totally new one. Several important CFs are valley-emphasis Otsu CF[5], class variance CF[4], entropy CF[6, 7], fuzziness CF[8], minimum error CF[9], and etc.. When thresholding according to CF, the image segmentation is considered as a classificaion problem. All of the CFs above assume that the gray-level probability distributions of objects and background are both normal, and the number of classes is predictable (that is how many kinds of objects in the background should be known before thresholding). FFIS can generate uniform lint slice and the lighting is well controlled. The gray-level of cotton fiber, which is background, distributes normally. But the gray-level of foreign fiber, which is object, varies in a wide range and its distribution can not be considered as normal. The class number is also unpredictable in foreign fiber inspection because there may be or not be foreign fiber, and there may be one kind or many kinds of foreign fibers. So the two assumptions obstruct the application of such thresholding methods in foreign fiber inspection, which may occur in other similar situations. A segmentation method may be suitable to some kinds of images, but there is not yet an universal method for all kinds of images. In this paper, a Background Estimation
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Thresholding(BET) method is developed specially for foreign fiber inspection. The experimental results show that the BET is effective and fast, and can be used in the online foreign fiber inspection in volumes of lint. The paper is organized as follows. In Section 2, we describe the BET method and its implementation. Section 3 gives the experimental results and the analysis comparing with valley-emphasis Otsu method. Finally, the paper is concluded in Section 4.
2 BET Method and Its Implementation 2.1 Method FFIS scans the uniform lint slice under well controlled lighting and the gray-level of cotton fiber distributes normally. Foreign fiber is darker than cotton fiber and its gray-level is lower. The histogram of a lint image containing foreign fibers is close to normal but extends to the dark side like a tail. Given a lint image with 256 gray-levels, the proportions of cotton fiber and foreign fiber are denoted by Pb and Po respectively, where Pb+Po=1. The gray-level distribution of cotton fiber can be formulated as: pb ( g ) =
1 2π σ
exp(−
( x − μ )2 2σ
2
(1) )
where μ is mean and σ is standard deviation, g=0,1,2,…,255. The gray-level distribution of foreign fiber, denoted by po(g), is unknown, which may be any form. For a threshold T, the lint image is segmented as follows. For every pixel, if its gray-level g
g
(a )
(2) g ≥T
(b)
(2.a) gives the error ratio where the background is marked as object and (2.b) gives the error ratio where the object is marked as background. Decreasing T can decrease (2.a) while increase (2.b), and vice versa. Pb(g) is a normal distribution and its mean and standard deviation can be estimated (described below), so (2.a) can be estimated. po(g) is unknown and therefore (2.b) can not be estimated. (2.a) can be estimated and controlled, it is realistic to select T based only on (2.a), which is a partial error ratio, not the whole error ratio commonly used. (2.a) can be controlled under an acceptable level by choosing T. For example, if T = μ − 3σ , (2.a)
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will be under 0.2%Pb; if T = μ − 4σ , (2.a) will be under 0.005%Pb. Such threshold T locates near the darkest gray-level of background. Decreasing T further has little help to decrease (2.a) while increase (2.b) rapidly. If the background is separable by gray-level value from the object, or their histogram do not overlap or overlap little each other, a T near the darkest gray-level of background will keep the error ratios of (2.a) and (2.b) low both, and the segmentation succeeds. Otherwise if their histogram overlap each other, (2.a) will be low while (2.b) high, which means many object pixels are marked as background, and the segmentation fails. Actually, segmentation will fail for any threshold choice in the latter, which means thresholding is not suitable for such kind of images. Fortunately, most foreign fibers are separate from the cotton fiber in gray-level and can be segmented by thresholding. White polypropylene twine is one inseparable from cotton fiber and can not be ignored in foreign fiber inspection in China. The ultraviolet scanner in FFIS is equipped specially for the detection of foreign fibers like this, which is separable from cotton fiber in the ultraviolet image. Here we describe how to estimate the mean μ and standard deviation σ of Pb(g), which is called background estimation. The cutton fiber is dominant in lint image and its gray-level distribution is normal, it is reasonable to take the gray-level with maximal probabilty in histogram as the estimation of mean μ. Most foreign fibers are darker than cotton fiber and all pixels with gray-level between μ ~ 255 are considered as background. These pixels constitute one half of the background samples, and then the another half can be mirrored centering at means μ. The standard deviation σ can be evaluated finally by Bayersian Estimation based on the background samples. BET method first do background estimation, and then select a threshold T to control the error ration of (2.a) under a predefined level (acquired by experiments). The background of lint image is stable and its gray-level distribution can be estimated, BET actually extracts the background by a threshold T, which depends on Pb(g) and a predefined limitation of error ratio. 2.2 Implementation The steps of segmentation by BET are as follows: Step 1. Computing the histogram h(g), g=0, 1, …, 255; Step 2. Mean estimation: μ=m, where h( m) = max {h( g )} ; 0≤ g ≤ 255
Step 3. Standard deviation estimation: 255
Pb = 2 × ∑ h( g ) + h(μ ) g = μ +1 255
D = 2 × ∑ h( g )( g − μ )2 g = μ +1
σ = D / Pb ;
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Step 4. Computing T: T = kσ ,3 ≤ k ≤ 4 , where k is predefined; Step 5. Segmentation: For every pixel in lint image, if its gray-level g
3 Experiment Results The lint images in our experiment can be divided into three categories, they are cotton fibers only, cotton fibers mixed with foreign fibers whose gray-levels distribute narrowly, and cotton fibers mixed with foreign fibers whose gray-levels distribute widely, which correspond to one class (unimodal), two classes (bimodal) and multiple classes (multimodal) in classification, respectively. The BET method is evaluated against all three categories of lint images. This section gives one example and its comparison with the valley-emphasis Otsu (VEOtsu) thresholding for each category. At the end of this section, the execution speed of BET is also discussed. 3.1 Unimodal Fig. 3 shows a lint image containing cotton fibers only, whose histogram demonstrates a normal distribution (202.69 in mean, 6.88 in standard deviation). Otsu method will split it at the mean and half of the image will be considered as foreign fiber. It will cause the measurement results meaningless because most lint images do not conrain foreign fiber.
(a)
(b) Fig. 3. (a) Lint containing cotton fibers only, (b) Histogram
VEOtsu marks all pixels as object, where T=233. BET marks all pixels as background, where the estimated μ=203.00, σ=6.87, predefined k=3.5, and the final T=179. Both of VEOtsu and BET can segment the unimodal image correctly, but VEOtus sometimes does wrong marking and BET never.
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3.2 Bimodal Fig. 2 shows a lint image containing a black hair and a small patch of cotton leaf, whose gray-level distributions are similar by chance. It is bimodal and Fig. 4 shows its segmentations by VEOtsu and BET.
(a)
(b) Fig. 4. Segmentation of Fig. 2(a), (a) by VEOtsu, (b) by BET
Both of VEOtsu and BET can segment the bimodal image correctly and the BET is closer to human beings. Several black points, labeled in a circle in Fig. 4(b), are contton fibers but segmented as foreign fibers by BET wrongly, because the thickness of lint slice is not uniform fully. These points should be removed in the postprocessing. 3.3 Multimodal Fig. 5(a) shows a lint image containing a feather and a small patch of cotton leaf, whose gray-level distributions in a wide range. Fig. 5(b) shows that the histogram drags a long but thin tail, which is multimodal. Fig. 5(c, d) are the segmentations by VEOtsu and BET respectively. In multimodal case, VEOtsu selects multiple thresholds and the implementation is different from the bimodal. Whether the lint image is unimodal, bimodal, or multimodal is unpredictable, so the bimodal implementation is used commonly by VEOtsu. The feather, shown in Fig. 5(c) is lost excessively by the VEOtsu. The BET selects only one threshold and the implementation is same regardless of the image modality. Fig. 5(d) demonstrates that the BET can segment multimodal image better than the VEOtsu.
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(a)
(b)
(d)
(c)
Fig. 5. (a) Lint containing feather, (b) Histogram in detail at the bottom, (c) Segmentation by VEOtsu, (b) Segmentation by BET
3.4 Execution Speed To find out the optimal threshold, the VEOtsu needs compute the CF, which includes 2 means and 2 variances, each for every 256 gray-levels. The BET needs find out the gray-level with the maximal probability and compute variance one time. The computation of VEOtsu is more than the BET’s and Table 1 shows their execution time for 1 million threshold selections(Intel Mobile Pentium 4 CPU, 2.0 Ghz), where the BET reduces the computation of the VEOtsu to 35.8%. Table 1. Execution time of VEOtsu and BET
Method
Execution time (Sec.)
VEOtsu
8.46
BET
23.62
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4 Conclusions The lint image containing foreign fiber features that the background (cotton fiber) is homogeneous and has a normal gray-level distribution; the object (foreign fiber) is smaller, darker than the background but its gray-level distributes is a wide range. The BET method can extract the foreign fibers from lint image well, which makes the detection and measurement by machine vision technology possible. Comparing with other thresholding methods such as Otsu, the BET can segment image with higher performance where the existence or types of object are unpredictable, and is suitable for foreign fiber inspection and other similar applications. The BET method can applied in foreign fiber inspection online in volumes of lints, where the simplicity and fast speed are greatly concerned. The thickness of lint slice is not uniform fully and the BET segments some cotton fibers wrongly as foreign fibers. This problem is left unresolved and the related researches are going on. Acknowledgements. This research was funded by National Natural Science Foundation of China (30971693) and Ministry of Education of People’s Republic of China (NCET-09-0731).
References 1. Yang, W., Li, D., Zhu, L., Kang, Y., Li, F.: A new approach for image processing in foreign fiber detection. Computers and Electronics in Agriculture 68(1), 68–77 (2009) 2. Lieberman, M.A., Bragg, C.K., Brennan, S.N.: Determining gravimetric bark content in cotton with machine vision. Textile Research Journal 68(2), 94–104 (1998) 3. Otsu, N.: A threshold selection method from gray-level histograms. IEEE Trans. On Systems, Man, and Cybernetics SMC-9(1), 62–66 (1979) 4. Hou, Z., Hu, Q., Nowinski, W.L.: On minimum variance thresholding. Pattern Recognition Letters 27, 1732–1743 (2006) 5. Ng, H.-F.: Automatic thresholding for defect detection. Pattern Recognition Letters 27, 1644–1649 (2006) 6. Kapur, J.N., Sahoo, P.K., Wong, A.K.C.: A new method for gray-level picture thresholding using the entropy of histogram. Computer Vision, Graphics, and Image Processing 29, 273–285 (1985) 7. Pun, T.: A new method for grey-level picture thresholding using the entropy of the histogram. Signal Processing 2, 223–237 (1980) 8. Huang, L.-K., Wang, M.-J.J.: Image thrsholding by minimizing the measures of fuzziness. Pattern Recognition 28(1), 41–51 (1995) 9. Kittler, J., Illingworth, J.: Minium error thresholding. Pattern Recognition 19(1), 41–47 (1986)
An Efficient Iterative Thresholding Algorithms for Color Images of Cotton Foreign Fibers Xin Zhang1, Daoliang Li2,*, Wenzhu Yang2, Jinxing Wang1, and Shuangxi Liu1 1
College of Mechanical and Electronic Engineering, Shandong Agricultural University, Taian, Shandong 271018, China 2 College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, P.R. China
Abstract. The goal of color image segmentation is to divide the image into homogeneous regions. Thresholding is a commonly used technique for image segmentation. Thresholding assumes that image present a number of components, each of a nearly homogeneous value, and that one can separate the components by a proper choice of intensity threshold. In this paper, we present an efficient iterative algorithm for finding optimal thresholds. In the first step, color images were captured, and the edge of color images were detected by edge detection method. In the second step, color images were converted into a gradient map, and then the regular of experience values were analyzed, at last the best threshold of the gradient map was chosen by selecting the best experience value iteratively. The experiment results indicate that the best threshold selection of the gradient map can precisely segment the high-resolution color images of cotton foreign fibers.
1 Introduction The foreign fibers in cotton refer to those non-cotton fibers and dyed fibers, such as hairs, binding ropes, plastic films, candy wrappers, and polypropylene twines, etc. Foreign fibers mixed with cotton during picking, storing, drying, transporting, purchasing and processing, are difficult to remove in spinning process, and can cause yarn breakage, even reducing the efficiency. Every low content of foreign fibers in cotton, especially in lint, will seriously affect the quality of the final cotton textile products, as they may debase the strength of the yarn, and are not easy to be dyed (Yang, et al.,2009). Therefore, various techniques have been employed to implement automatic inspection and removal of foreign fibers in lint, including ultrasonic-based inspection, sensor-based inspection, and machine-vision-based inspection, etc. In recent years, machine vision systems have been applied to textile industries (Tantaswadi et al., 1999; Millman et al., 2001; Abouelela et al., 2005) for inspection and/or removal of foreign matters in cotton (Lieberman et al., 1998) or wool (Su et al., 2006). The recognition of foreign fibers of targets is the key machine vision technology, in which image segmentation is an important step. Thresholding is a simple and *
Corresponding author.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 710–719, 2011. © IFIP International Federation for Information Processing 2011
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commonly used technique for image segmentation (M. Fornasier et al., 2007). It aims to group the image pixels by checking the pixel intensities against a set of thresholds. Searching for optimal thresholds with respect to a particular objective function has always been one of the fundamental problems in image processing. Numerous methods have been proposed in the past (Sankur and Sezgin, 2004; Tancredi A. et al., 2006; Yin, 2002; Cheng et al., 2000). The methods mentioned above may work well in their specific context, but it’s not capable to segment images of cotton foreign fibers because of the low contrast. Due to the uneven thickness of the layers of cotton and foreign fibers of different colors and shapes, using the above conventional image segmentation methods may lead to significant variations of segmentation for foreign fibers. It is hard to attain a satisfying result by using one segmentation method. In this article, a novel method based on mathematical morphology and iterative thresholding method is proposed to segment such low-contrast images.
2 Materials and Methods The foreign fibers used in this research were collected from cotton mills which included feathers, hair, hemp rope, plastic films, polypropylene twine, colored thread, cloth piece etc. Adequate pure lint with no foreign fibers was also prepared for making the lint layer. The experiment selected a sufficient amount of lint cotton which does not include foreign fibers. 2.1 Materials Preparation The Image Acquisition System is the most important part in this experiment platform. It consist mainly of two cameras, two light sources, one shaft encoder, one synchronizing amplifier, two image acquisition boards and a computer, as shown in Figure 1.
Fig. 1. The image acquisition system
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By observing the images obtained, it was easy to find that the opened foreign fibers appears in three typical forms, as shown in Fig. 2a–c, (1) sheet, such as plastic films, papers, etc., (2) wirelike, such as hair, color thread, etc., and (3) villiform, such as hemp rope, chemical fibers, etc.
(a)
(b)
(c)
Fig. 2. Acquired color image examples: (a) opened plastic film, (b) opened hair, and (c) opened hemp rope
2.2 Iterative Method Principle The identification of cotton foreign fibers is done through real-time monitoring, however, when it is in different circumstances, it will have different light intensity. Therefore, the target segmentation for foreign fibers can not be through a fixed thresholding value to segment. In this case, the thresholding was automatically selected by iterative method in this paper. Thresholding is the most widely used image segmentation method. Thresholding algorithm has histogram bimodal method(also known as the mode method), Otsu method and the iterative threshold method, etc. Histogram bimodal method is used to some simple images, which appear two separate peaks in histograms, and then the troughs which correspond gray value between two peaks was selected as threshold value. Iterative threshold method is the improved method of histogram bimodal, and it is an automatic process of selecting threshold, which is described as follows: (1) The gradient map can be acquired through the edge detection method of mathematical morphology. To calculate the min gray value Z1 and max gray
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value Z k of this gradient map, defined thresholding to initial value:
Z1 + Z k 2
T0 =
(1)
(2) Gray gradient map is divided into two parts, object and background, through the
T k , and then calculating the target average gray value Z 0 and the background average gray value Z B ; thresholding
∑
z (i, j ) × N (i, j )
z ( i , j )
Z0 =
∑
N (i, j )
(2)
z ( i , j )
ZB =
∑
z (i, j ) × N (i, j )
z ( i , j ) >T k
∑
N (i, j )
(3)
z ( i , j ) >T k
z (i, j ) is (i, j ) point on gray value of gray gradient map, N (i, j ) is weight coefficient of (i, j ) point, N (i, j ) =1.0; In the above formulas,
(3) Obtaining a new adaptation thresholding of cotton foreign fibers:
T k +1 = n × ( Z 0 + Z B ) The value
(4)
n of conventional iterative threshold method is 0.5, but this value is not
suitable for images of cotton foreign fibers, hence, this paper presents the experienced value method for selecting value
n.
3 Results and Discussion Seven typical foreign fibers, namely, plastic film, feather, polypropylene twine, hair, color thread, hemp rope and cloth piece, were selected for the experiments. Ten samples were prepared for each type of foreign fibers. That is to say, there are totally 70 foreign-fiber samples. Matlab 7.0 was used to implement and validate the algorithm. An Intel Core 2 Duo CPU personal computer with 2GB SDRAM was chosen as the test environment and Windows XP was selected as the operation system.
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3.1 Analysis of the Improved Threshold Selection of Iterative Method In order to increase the range of differences as far as possible, the range is defined from 0.1 to 0.9. Table1 to Table3 are the final iteration threshold
Tnext and the previous
threshold comparison of the results between wirelike, villiform and sheet foreign fibers. Table 1. Comparison of experiment results of hair Experience 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 value 0.012128 0.13321 0.50269 0.50269 0.50269 0.50269 0.50269 0.50269 0.50269
T Tnext
0.066604 0.063806 0.19981 0.26641 0.33302 0.39962 0.46623 0.53283 0.59943
Table 2. Comparison of experiment results of feather Experience 0.1 value
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
T
0.066206 0.13241 0.51063 0.51063 0.51063 0.51063 0.51063 0.51063 0.51063
Tnext
0.020063 0.075758 0.19862 0.26482 0.33103 0.39724 0.46344 0.52965 0.59585
Table 3. Comparison of experiment results of plastic film Experience 0.1 value
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
T
0.065354 0.13071 0.48571 0.48571 0.48571 0.48571 0.48571 0.48571 0.48571
Tnext
0.013167 0.073519 0.19606 0.26142 0.32677 0.39212 0.45748 0.52283 0.58819
Table 1 to Table 3 show that when the value
n is between 0.3 to 0.9, no matter what
wirelike, villiform and sheet foreign fibers in the previous thresholds are equal, that is, only when n > 0.2, the value
T began to significantly change, therefore, n = 0.2 is the
mutation point of thresholding selection. The following images are intuitively verifying this experience value. The Fig. 3 are the typical images of wirelike, villiform and sheet form foreign fibers. The range of experience value is from 0.1 to 0.5, step is 0.1.The follows are the effected images.
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(a1)-(a3) Original color images (b1)-(b3) (e1)-(e3)
n =0.4
(f1)-(f3)
n =0.1
(c1)-(c3)
n =0.2
(d1)-(d3)
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n =0.3
n =0.5
Fig. 3. Original color images and its effected images
From the above Fig. 3 shows that, when n > 0.2, the clarity of target image decreased gradually, and when n = 0.6 ~ 0.9, the effected images for all kinds of foreign fibers become increasingly unobvious , so that wirelike form foreign fibers is difficult to see the target image, thus this paper doesn’t list this range images. When n = 0.1, as it is too small, the binary images are acquired almost black. From analysis above, it is concluded that , when n =0.2, the selected thresholding is fit for most gray gradient maps for foreign fibers, and then getting the most clearly binary object images, formula (13) can be written as:
T k +1 = 0.2 × ( Z 0 + Z B ) (4)If T = T k
k +1
, it is terminated, or letting K ← K + 1 , go to step (2).
3.2 Analysis of Optimal Threshold Selection Fig. 4 are color images of hair and the plastic film for cotton-fiber and its histogram. Histogram analysis in Fig.4 shows that almost all histograms are single peak. The main
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reason for the histogram being of single peak is that the content of the foreign fiber in lint is very low, and it leads to small number of pixels for foreign fibers in the image. Therefore, it can not be acquired thresholding according to double peaks method.
(a)
(b)
(c)(d) (a) original color image of blue polypropylene
(b) histogram of blue polypropylene image
(c) original color image of hemp rope
(d) histogram of hemp rope image
Fig. 4. Original color images and its histogram
The Otsu’s method (Otsu, 1979), which is also called maximum between-group variance method, is a kind of adaptive thresholding method which has the optimal threshold according to the statistics. The defect of Otsu’s method is when the target and background gray scale difference is not obvious; it will lead to error segmentation, even losing the whole image information. The segmentation of hemp rope for cotton foreign fibers belongs to this case. Fig.5 is color image of hemp rope and its segmented image by Otsu’s method for cotton foreign-fiber. Based on above analysis of experimental and theoretical, in order to solve a problem when object and background gray scale difference is not obvious leading to loss of
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(a)- (c) Original color images of hair, hemp rope and plastic film (d)- (f) gray gradient images of hair, hemp rope and plastic film (g)- (i) segmented images by iterative threshold method of hair, hemp rope and plastic film Fig. 5. Original color images and its segmented image by iterative threshold method
image information, this paper presents a new approach for image segmentation which includes several steps. In the first step, color images were captured, and the edge of color images were detected by edge detection method. In the second step, color images
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were converted into a gradient map, and then the regular of experience values were analyzed, at last the best threshold of the gradient map was chosen by selecting the best experience value iteratively.Fig.5 are original color images of three typical foreign fibers and their gray gradient maps, and segmented images by iterative thresholding method.
4 Conclusion In this paper, research and analysis of the relationship and regular of thresholding for final iteration and the previous iteration, which are after the iteration for wirelike, villiform and sheet foreign fibers. At last the experience value is determined, which is fit for the gray gradient map of most foreign fibers, thus the clear binary image is obtained. The segmentation results indicate that the method of this paper can content the premise accuracy for image segmentation of foreign-fiber. The mandate of speed is a key factor for the online visual inspection system. Hence, in addition to ensuring the segmentation accuracy, algorithms with faster speed is now being studied.
Acknowledgements The authors would like to thank The National Natural Science Foundation of the People’s Republic of China (30971693), and New Century Excellent Talents of Ministry Education (NCET-09-0731) for their financial support.
References Abouelela, A., Abbas, H.M., Eldeed, H., Wahdam, A.A., Nassar, S.M.: Automated vision system for localizing structural defects in textile fabrics. Pattern Recognition Letters 26(10), 1435–1443 (2005) Cheng, H.D., Chen, Y.H., Jiang, X.H.: Thresholding using twodimensional histogram and fuzzy entropy principle. IEEE Trans.Image Process. 9, 732–735 (2000) Lieberman, M.A., Bragg, C.K., Brennan, S.N.: Determining gravimetric bark content in cotton with machine vision. Textile Research Journal 68(2), 94–104 (1998) Millman, M.P., Acar, M., Jackson, M.R.: Computer vision for textured yarn interlace (nip) measurements at high speeds. Mechatronics 11(8), 1025–1038 (2001) Fornasier, M., Pitolli, F.: Adaptive iterative thresholding algorithms for magnetoenceophalography (MEG). J. Comput. Appl.Math. (2007) (in press), doi:10.1016/j.cam.2007.10.048 Sankur, B., Sezgin, M.: A survey over image thresholding techniques and quantitative performance evaluation. J. Electron. Imaging 13(1), 146–165 (2004) Su, Z.W., Tian, G.Y., Gao, C.H.: A machine vision system for on-line removal of contaminants in wool. Mechatronics 16(5), 243–247 (2006) Tantaswadi, P., Vilainatre, J., Tamaree, N., Viraivan, P.: Machine vision for automated visual inspection of cotton quality in textile industries using color isodiscrimination contour. Computers & Industrial Engineering 37(1–2), 347–350 (1999)
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Tancredi, A., Anderson, C., O’Hagan, A.: Accounting for threshold uncertainty in extreme value estimation. Extremes 9, 86–106 (2006) Yang, W., et al.: A new approach for image processing in foreign fiber detection. Comput. Electron. Agric. (2009), doi:10.1016/j.compag.2009.04.005 Yin, P.Y.: Maximum entropy-based optimal threshold selection using deterministic reinforcement learning with controlled randomization. Signal Process 82, 993–1006 (2002)
Application of Grey Prediction Model in Rural Informatization Construction Jing Du1,3, Daoliang Li2, Hongwen Li1,*, and Lifeng Shen2 1
College of Engineering, China Agricultural University, 17 Tsinghua East Road, P.O. Box 46, Beijing, 100083, P.R. China [email protected] 2 College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China 3 China Agricultural University Library, Beijing 100083, China
Abstract. Grey system theory has been widely applied to many domains such as economy, biology, agriculture, control and so on. Based on the theory of grey system, this paper established GM(1,1) grey predict modeI for the first time to forecast Chinese every hundred rural households owned computers and every hundred rural households owned mobile phone. The predicting results are almost close to the actual values, and this shows that the model is reliable. Finally, these models are used to forecast the two factors in the future years. The research provides a new seientific method for predicting rural informatization development. Keywords: Rural informatization, GM(1,1) model, grey theory.
1 Introduction Agriculture and rural informatization is an important component of the national economy informatization. Setting up prediction model is very significant for the social and economic systems. Because rural informatization is a society-economynature complex system, there are many kinds of factors afflecting rural informatization level, and it is difficult to confirm all influencing factors. Besides, some factors are indefinite, some are definite but difficult to be described quantitively and some are quantified but they may have randomness. Therefore, we can think that rural informatization is a gery system. Since grey system analysis method has fine adaptability to actua1 situation when information is incomplete, rural informatization system can be studied using grey theory, among which single sequence one order GM(1,1) model can be applied. The following work will introduce the principle of grey topologica1 forecast and a grey predicting model is set up. This model can be fully processed at a quantity level on the basis of history data to realize a scientific prediction [1]. *
Corresponding author. Tel.: +86-10-62737631, Fax: +86-10-62737300.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 720–726, 2011. © IFIP International Federation for Information Processing 2011
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2 The Basis of Grey Prediction Method 2.1 Grey System Theory The grey theory, developed originally by Deng (1987), is a multidisciplinary and generic theory that deals with systems that lack adequate information and/or have only poor information. The fields covered by the grey theory include systems analysis, data processing, modeling, prediction, decision making and contro1. The grey theory mainly conducts systems analysis with poor, inadequate or uncertain messages. Grey prediction models have been extensively used in many applications [2]. In contrast to statistical methods, the weight of the original series in the time series grey model, called GM(1,1), has been proven to be more than four. This model is a time series forecasting mode1, encompassing a group of differential equations adapted for parameter variance, rather than a first order differential equation. Its difference equations have structures that vary with time rather than being general difference equations. In addition assumptions regarding the statistical distribution of data are not necessary when the grey theory is applied. The accumulated generation operation (AGO) is one of the most important characteristics of the grey theory, and its main purpose is to reduce the randomness of data. In fact, functions derived from AGO formulations of the original series are always well fired to exponential functions [3-5]. 2.2 Grey GM (1,1 ) Prection Model The GM(1,1) model is one of the most frequently used grey forecasting models. This model is a time series forecasting model, encompassing a group of differential equations adapted to parameter variance, rather than a first-order differential equation. Its difference equations have structures that vary with time rather than being general difference equations. Although it is not necessary to employ all the data from the original series to construct the GM(1,1) model, the weight of the series must be more than four. In addition, the data must be taken at equal intervals and in aconsecutive order without by passing any data. The GM(1,1) model constructing process is described below [4]: Denote the original data sequence by X
(0)
= (X
The AGO formation of
( 0)
(1), X
(0)
(2), " , X
( 0)
( n ))
(1)
X (0) is defined as:
X (1 ) = ( X (1 ) (1), X (1 ) ( 2 )," , X (1 ) ( n ))
(2)
Where X
(1)
(1) = X
(0)
(1) and X
(1)
k ( k ) = ∑ X (0) ( m), k = 1, 2, " , n m=1
(3)
The GM(1,1) model can be constructed by establishing a first-order differential equation for
X (1) as:
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d X (1 ) + aX dt
=
(1 )
(4)
μ
Where, α is the grey coefficient, μ is the grey control parameter. If the estimating parameter vector 5 is defined as: (5)
α ˆ = ⎡⎢ aμ ⎤⎥ ⎣ ⎦
And it use the least square method,
αˆ
= ⎡⎣ B T B ⎤⎦
−1
T
B
(6)
Yn
Then, the solution of Eq.(4) can be obtained by using the least square method. That is, Xˆ
(1)
( k + 1) = ( X
(0)
(1) −
μˆ − αˆ k μˆ )e + , k = 1, 2, " , n αˆ αˆ
(7)
Where αˆ = ⎡⎣ αˆ , μˆ ⎤⎦
T
= ⎡⎣ B T B ⎤⎦
−1
B
T
(8)
Yn
And ⎡ ⎢− ⎢ B = ⎢− ⎢ ⎢ ⎢− ⎣⎢
1 2 1 2
⎡X ⎣ ⎡X ⎣
(1 )
(1 ) + X
( 2 )⎤ ⎦ (1 ) (1 ) (2 )+ X (3)⎤ ⎦ # #
1⎡ X 2⎣
(1 )
( n −1 ) + X
(1 )
(1 )
( n )⎤ ⎦
⎤ 1⎥ ⎥ 1⎥ ⎥ ⎥ 1⎥ ⎦⎥
(9)
And (10)
⎡ (0) ⎤ ⎢ X (0) (2)⎥ (3) ⎥ Yn = ⎢ X ⎢ ⎥ # ⎢ X ( 0 ) ( n )⎥ ⎣ ⎦
Xˆ (1) is obtained from Eq.(7). Let Xˆ (0) be the fitted and predicted series, Xˆ
(0)
= ( Xˆ
(0)
(1 ), Xˆ
(0)
( 2 ), " , Xˆ
(0)
( n ))
(11)
Where Xˆ
(0)
= X
(0)
(1 )
(12)
Application of Grey Prediction Model in Rural Informatization Construction
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Applying the inverse AGO, then have Xˆ
(0)
( k + 1 ) = ( Xˆ
α
(1 )
( k + 1 ) − Xˆ
(1 )
(13) (k )
−α k
) ⎡⎣ ( X
(0)
(1 ) − μ / α ) ⎤⎦ e
Where Xˆ ( 0 ) (1 ), Xˆ ( 0 ) ( 2 )," , Xˆ
(0)
( n ) are called the GM(1,1) fitted sequence,
= (1 − e
( n + 1 ), Xˆ ( n + 2 )," , are called the GM(1,1) prediction values. while Xˆ After the above model is generated and developed, further tests are necessary to underst and the error of forecasted value, as compared to the actual value. To demonstrate the efficiency of the proposed forecasting model, we adopted the residual error test method to compare the actual value and the forecasted value. Here, Equations (14) and (15) are used to compute the residual error of the Grey forecasting. (0)
(0)
Error =
(14)
X ( k ) − Xˆ ( k ) X (k )
1
n
Average error = k ∑ k =1
(15)
X ( k ) − Xˆ ( k ) X (k )
3 Grey Prediction of Rural Informatization Infrastructure Based on the characteristics of rural informatization, this paper choose two factors to be predicted, one is every hundred rural households owned computers, the other is every hundred rural households owned mobile phones [6]. Between 2000 and 2008, the every hundred rural households owned computers, the every hundred rural households owned mobile phones in China are listed in Table1.
Table 1. Annual values of the two rural informatization factor between 2000-2008
Time
Every hundred rural households owned computers
Every hundred rural households owned mobile phones
2000
0.5
4.3
2001
0.7
8.1
2002
1.1
13.7
724
J. Du et al. Table 1. (continued)
2003
1.4
23.7
2004
1.9
34.7
2005
2.1
50.2
2006
2.7
62
2007
3.68
77.84
2008
5.3578
96.13
Based on the data in Table1 and the above principle of grey forecasting, we can get the coefficients in the model through calculation. And then we get grey forecasting model GM(1,1) of every hundred rural households owned computers and every hundred rural households owned mobile phones. By using DPS9.05, The predicted values obtained by the proposed GM(1,1) model and their respective errors are shown in Table2 and Table3. Table 2. Model operation results of every hundred rural households owned computers
Model parameter
a=0.006531
b=0.156794
X(k+1)= -23.680009exp(-0.006531k)+24.006336 No.
Actual value
Predicted value
2001
0.7
0.792
-0.022
-3.3033
2002
1.1
1.2313
-0.0812
-7.5411
2003
1.4
1.5064
-0.1066
-8.4386
2004
1.9
1.8782
0.11
5.7485
2005
2.1
1.9008
0.2217
10.859
2006
2.7
2.7173
0.1202
4.6554
2007
3.68
3.989
-0.1551
-4.3817
2008
5.3578
5.8581
-0.0911
-1.7495
The evaluation of the model
C=0.0816
Very good
p=1.0000
Very good
Error
%
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Table 3. Model operation results of every hundred rural households owned mobile phones
Model parameter
a=0.152491
b=29.303635
X(k+1)=-160.819281exp(-0.152491k)+192.166756 No.
Actual value
Predicted value
Error
%
2001
8.1
7.4016
1.3424
16.7172
2002
13.7
17.1468
-2.2686
-16.3302
2003
23.7
28.3539
-2.4442
-10.3129
2004
34.7
36.5123
-0.6278
-1.7376
2005
50.2
48.8886
5.3954
10.6858
2006
62
56.7101
4.0001
6.5668
2007
77.84
78.187
1.9737
2.6764
2008
96.13
112.1695
-8.1425
-8.8905
The evaluation of the model C=0.1273
Very good
p=1.0000
Very good
We can test the grey model by using the second errors, the average values of absolute values of relative errors respectively are being 0.0816 and 0.1273, which show that the established grey model have a good accuracy. It can be seen that the simulation results from 2001 to 2008 have a good degree of fitting. This shows that the forecasting model possesses the better forecasting precision and the forecasting resu1ts are believable. Based on these forecasting values, we can ca1cu1ateted annual every hundred rural households owned computers and every hundred rural households owned mobile phones values in China between 2010 and 2013 which is listed in Table4. Table 4. Predicted values of the two rural informatization factor between 2009-2013
Time
Every hundred rural households owned computers
Every hundred rural households owned mobile phones
2009 2010 2011 2012
7.36 9.69 12.74 16.75
115.58 159.20 217.13 293.86
2013
22.01
395.29
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4 Conclusion and Recommendations Based on the grey system theory, two predicting model of rural informatization infrastructure factors have been set up. From the predicting results, its forecasting precision is higher. And the model needs fewer indexes, and thus is simple and convenient to calculate in practical application. The research results show that when the grey forecasting technology is used in the middle and short-term prediction, this method has higher confidence and can be as a quantitative forecasting method of rural informatization infrastructure factors. The study of this paper offers a new method and approach to predict for rural informatization development. But the establishment of grey predicts system is not once and for all. The accuracy of predict result is based on the amount and reliability of information we have had. We think it is essentially accurate and reliable for predicting the next period after a new grey prediction system has been estab1ished [7]. We should modify grey parameters in time and establish new prediction model based on the risk of new information we have got. Then the credibility of prediction result can be greatly improved with the new model.
References 1. Sun, J.: Forecasting model of coal requirement quantity based on grey system theory. Journal of China University of mining & Technology 11(2), 192–195 (2001) 2. Liu, J., Xue, H., Wu, D.J.: Application of improved grey model in the settlement prediction of roadbed foundation. Geography Technical Engineering 19(2), 59–63 (2005) 3. Deng, J.: Grey system essential method. Huazhong University of Science and Technology Press, Wuhan (1996) 4. Li, J., Wang, B., Zhang, B.: Application of Improved Grey Prediction Model to Petroleum Cost Forecasting Petroleum Science, vol. 3(2), pp. 89–92 (2006) 5. Ma, Q., Cao, J.: Grey forewarning and prediction for mine water inflowing catatrophe periods. Journal of Coal Science & Engineering(China) 13(4), 467–470 (2007) 6. Qin, X., Zhang, X., Zhang, X.: Study on assessment index system for rural informatization in Beijing. Journal of Beijing Agricultural Vocation College 22(1), 42–46 (2008) 7. Wu, M., Qiu, S., Liu, J., Zhao, L.: Prediction Model Based on the Grey Theory for Tackling wax deposition in oil Pipelines. Journal of Natural Gas Chemistry 14, 243–247 (2005)
Study on Evaluation Method for Chinese Agricultural Informatization Xiaoqing Yuan, Liyong Liu, and Daoliang Li* College of Information and Electrical Engineering, China Agricultural University, 17 Tsinghua East Road, P.O. Box 121, Beijing, 100083, P.R. China [email protected]
Abstract. According to China’s current situation in agricultural informatization development and the functions of the Ministry of Agriculture, and on a basis of the connotation of “agricultural informatization”, this paper initially establishes a quantitative agricultural informatization evaluation index system which could reflect the actual level of every province’s agricultural informatization. The index system consists of 12 indexes selected from 3 aspects, which are agricultural informatization foundational support level, agricultural production and operation informatization level, as well as agricultural management and service informatization level. At the same time, on the basis of summarizing the accomplishments of other researchers, a set of calculation methods/algorithms are proposed in the paper to evaluate the agricultural informatization level. Keywords: Agricultural informatization; Index system; Evaluation method.
1 Introduction Informalization is the general trend of current world economic and social development. The rapid development and overall permeation of information technology will provide agriculture production and rural social and economic development of our country with the new development opportunities. So it is a very important act to vigorously promote agricultural informalization, make full use of information technology to transform traditional agriculture for developing modern agriculture, train new peasants and accelerate the construction of new socialist countryside. Especially, it has strategic significance on promoting agriculture productivity great-leap-forward development in our country (The Ministry of Agriculture, Apr.,2010). In recent years, the Central Committee of the Party and the State Council put high values on the work of agricultural informalization, put forward series of policies, carried out a number of engineering projects. Driven by these engineering projects, the agricultural informalization infrastructure construction has been speeding up continuously, the agricultural informalization application level has kept improving, the construction of agricultural informalization has been enhanced obviously (Li.,Oct.,2009). *
Corresponding author. Tel.: +86-10-62736764; Fax: +86-10-62737741.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 727–734, 2011. © IFIP International Federation for Information Processing 2011
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Agricultural informatization is a systematic engineering project, it requires large amount of investment and long construction period (Yin.,Apr.,2004). If there is no scientific agricultural informatization evaluation system to guide it, it will inevitably cause a great waste of resources. Therefore, establishing a scientific agricultural informatization evaluation system to make quantitative analysis of the level of agricultural informatization has far-reaching strategic significance and important practical significance (Chen.,Oct.,2007). It will help each province not only know explicitly the stage of their agricultural informatization level, but also improve the management and decision-making level of their agricultural informatization level. Based on the above facts, this article will establish a quantitative evaluation index system that could reflect the actual agricultural informatization level of each province in China with the principles of integrity, operability, orientation and cohesion, according to China’s current situation of agricultural informatization development and the specific functions of the Ministry of Agriculture.
2 The Concept and Connotation of Agricultural Informatization 2.1 The Concept of Agricultural Informatization Agricultural informatization is a component of informatization, “2006-2020 National Informatization Developmental Strategy” has given the following definition to the informatization: informatization is a historic process that can make full use of information technology, develop and utilize information resources, promote information exchange and knowledge sharing, improve the quality of economic growth, promote economic and social development and transformation. Agricultural informatization put more emphasis on information technology applied to agriculture. Based on this judgment and the function scope of the Ministry of Agriculture, this research makes the following definition for agricultural informatization: agricultural informatization is the degree and process of the making full development and use of various information technology equipments and information resources to apply modern information technology to all aspects of agricultural production and operation, and agricultural management by promoting the construction of information infrastructural facilities such as rural broadcasting and television network, telecommunication network and computer network. 2.2 The Main Content of Agricultural Informatization Embarking from the definition of Agricultural Informatization and the current situation, the articles believes that the core content of Agricultural Informatization should include three closely interrelated aspects: agricultural informatization foundational support, agricultural production and operation informatization, agricultural management and service informatization.
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2.2.1 Agricultural Informatization Foundational Support Agricultural informatization foundational support is a very important foundation for Agricultural Informatization. Agricultural informatization foundational support mainly include three basic network systems, they are broadcasting and television network, telecommunication network, and computer network, which covers radio, television, telephone, mobile phone, computer and other information terminals. Meanwhile, agricultural informatization foundational support also includes the degree of attention each province pay to informalization. It is specifically embodied in investment on Agricultural Informatization. 2.2.2 Agricultural Production and Operation Informatization Agricultural production and operation informatization is among the important terms proposed in Third Plenary Session of the Seventeenth Central Committee of the Chinese Communist Party, which mainly contains crop farming informatization, animal husbandry informatization, fishery informatization and agricultural products electronic transaction. 2.2.3 Agricultural Management and Service Informatization Agricultural management and service informatization needs to be realized by information technology. It mainly contains the agricultural E-government management level,proportion of agricultural informatization administrators in agriculture department,coverage of administrative village information service station,and proportion of rural information staff in agricultural population.
3 Establishment of AgriculturaI Informatization Evaluation Index System 3.1 Principles of Index System Design The design of agricultural informatization evaluation index system is based on the following four principles.Integrity principle: The agricultural informatization evaluation index system covers 2 aspects, it could reflect not only the agricultural informatization foundational support level, but also the agricultural informatization application level.Operability principle: The design of the index system is based on current agricultural informatization development realities in China, values the index data availability. The data could be obtained from Statistics Bureau of every province or provided by marketing division of agriculture department of each province.Orientation principle: combined with the trends of agricultural informatization, some indexes are forward-looking ,which can guide each province’s development.Cohesion principle: The agricultural informatization evaluation index system is upward linked up with the national informatization evaluation index system and downward reflecting the agricultural informatization development characteristics.
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3.2 Composition of Index System China’s agricultural informatization evaluation index system refers to the national informatization evaluation index system, meanwhile it closely combined with China's current development situation of agricultural informatization and the function scope of the Ministry of Agriculture. The index system is aimed at reflecting the actual situations and characteristics of China’s agricultural informatization, and also promoting the agricultural informatization schedule gradually. Initial assumption of the index system contains the agricultural informatization foundational support level, the agricultural production and operation level, and the agricultural management and service level, it total, it is 12 specific indicators in 3 aspects, as shown in table 1. Table 1. Agricultural Informatization Evaluation Index System One-level index
Agricultural Informatization Foundational Support Level
Agricultural Production and Operation Informatization Application Level
Agricultural Management and Service Informatization Application Level
Two-level index
No.
Unit
Data origin
Average number of computers per 100 families
1
PCS/100 families
Provincial statistics bureau
Average number of mobiles per 100 persons
2
PCS/100 persons
Provincial statistics bureau
Proportion of cabletele vision users
3
%
Provincial statistics bureau
Government Investment proportion of the agricultural informatization
4
%
Provincial Agriculture Department Market Department or information ceter
Crop Farming Informatization Index
5
%
the same as above
Animal Husbandry Informatization Index
6
%
the same as above
Fishery Informatization Index
7
%
the same as above
Agricultural Products e-commerce Transaction Proportion
8
%
the same as above
E-Government Agriculture Management Level
9
%
the same as above
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Table 1. (continued) Proportion of Agricultural Informatization Administrators in Agriculture Department
10
%
the same as above
Coverage of Administrative Village Information Service Station
11
%
the same as above
Proportion of Rural Information Staff in agricultural population
12
%
the same as above
4 The Calculation Method of Agricultural Informatization Index System 4.1 The Determination of Index Standard Value Index standard value, also called target value every index needs to achieve, is a periodical target description for agricultural informatization development. The selection of the values refers to the current values of provinces that have got a good development in agricultural informatization. But the standard values are higher than the current values from those provinces. These necessary values for evaluation index system could be used to definite the direction of agricultural informatization development. According to related state statistics and the understanding of each province’s agricultural informatization, we tentatively definite standard values for 12 indexes, as shown in table 2. After more accurate understanding on each province’s agricultural informatization index values, the standard index values could be adjusted appropriately. 4.2 Non-dimensional Processing of the Index Values Due to the differences among the units of each index, the evaluation results could not be compared and calculated directly. In order to solve the problem with different units that cannot be calculated comprehensively, we make date dimensionless, compare the actual value with the standard value and convert the actual values dimensionless in range from 0 to 100. Converted dimensionless values could be directly used to compare provincial agricultural informatization differences, and also could be used to calculate the final result of agricultural informationization evaluation with weighting values. The formula (1) is the index values non-dimensional formula.
Ti =
, ,
,
Ri × 100 Pi
(1)
In this formula i =1 2…12 i is the number of the 12 indexes; Ti is the dimensionless value of the ith index; Ri is the actual value of the ith index, got from the statistics; Pi is the standard value of the ith index, determined by the discussion in above texts.
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4.3 The Calculation of the Agricultural Informatization Evaluation Result The final agricultural information evaluation result comes out from weighting the 12 dimensionless values, it ranges from 0 to 100. The total agricultural information evaluation result is also called agricultural informatization index, used in horizontal and vertical comparison. It is useful to thoroughly understand each province’s agricultural informatization development level and effectively develop each province’s agricultural informatization work. Formula 2 is to calculate the final agricultural informatization evaluation result, it comes out directly from weighting the 12 dimensionless values.
()
(2)
12
I = ∑ Ti ⋅ Wi
, ,
i =1
,
In this formula i =1 2…12 i is the number of 12 indexes;I is the agricultural informatization index;Ti is the dimensionless value of the ith index;Wi is weight of the ith index. 4.4 Demonstration of Calculation In order to examine the accuracy of the above calculation method, this section takes A province as a example to demonstrate the process of agricultural informatization index calculation method (as shown in table 2). Table 2. A province Agricultural Informatization Evaluation Index System Calculation Data Table
No.
Index Name
Weighting
Wi
Unit
Standard Value
Pi
Actual Value
Ri
Dimensionless Value
Ti
1
Rural Computer Ownership Numbers per 100 Families
15
PCS/100 Families
50
5
10.0
2
Rural Mobile Phone Ownership Numbers per 100 persons
9
PCS/100 Persons
70
35
50.0
3
Rural CATV Ownership Rate
6
%
100
60
60.0
4
Proportion of Agricultural Informatization Investment in Government Investment on Agriculture
5
%
100
60
60.0
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Table 2. (continued) 5
Crop Farming Informatization Index
10
%
5
2
40.0
6
Animal Husbandry Informatization Index
10
%
10
5
50.0
7
Fishery Informatization Index
10
%
10
5
50.0
8
Agricultural Products Electronic Transaction Proportion
10
%
100
90
90.0
9
E-Government Agriculture Management Level
5
%
100%
80
80.0
10
Proportion of Agricultural Informatization Administrators in the Ministry of Agriculture
5
%
1
0.6
60.0
11
Information Service Station Coverage in Administrative Villages
10
%
100
75
75.0
12
Proportion of Rural Messengers in Agricultural Stuffs
5
%
0.1
0.06
60.0
The final evaluation result of A province agricultural informatization index is: I =52.50.
5 Conclusions Embarking from the connotation of Agricultural Informatization, this article presents an agricultural informatization level evaluation index system, which includes 3 one-level indexes and 12 two-level indexes. Meanwhile, this article proposes the agricultural informatization evaluation method in detail. The established agricultural informatization evaluation index system has strong operability and orientation, each index is measurable and quantitative with data from statistics bureau, and provincial agriculture department market department or information ceter of each province. The index of agricultural informatization obtained from calculating could definite every province’s agricultural informatization development level clearly. And the standard value of each index can provide each province necessary reference data for the agricultural informatization construction.
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Acknowledgements The authors thank Ministry of Agriculture of People’s Republic of China for their financial support.
References [1] China Rural and Agricultural Informatization Development Report. The Ministry of Agriculture (2010) [2] Li, D.I.: China Rural Informatization Development Report. Publishing House of Electtonics Industry, Bejing (2009) [3] Chen, Z., Cao, D.I., Liang, B.S., Ma, X.M.: Study on agricultural informatization evaluation based on principal component analysis. Journal of Henan Agricultural University 41(5) (2007) [4] Liu, S.H.: Agricultural Information Technology and Rural Informatization. China Agricultural Science and Technology Press, Bejing (2005) [5] Yan, X.L.: Building Chinna characteristics,agricultural information. Technology andIndustry (4), 24–29 (2004) [6] Song, L.: Theory and Method for the Measurement of Informatization Level. The Economic Science Press, Beijing (2001) [7] Zhong, Y.X., Shu, H.J., Lv, T.J.: A New Method for Estimating Informatization Level (CIIC), pp. 179–189. The Economic Science Press, Beijing (2001) [8] National Informatization Evaluation Center. Measurement and Comparison of the Informatization Level in China, http://www.niec.org.cn [9] Zheng, T.R.: A preliminary analysis of‘ the framework of national informatization indices. Information Science (1), 100–102 (2003) [10] Grimán, A., Pérez, M., Mendoza, L., Losavio, F.: Feature analysis for architectural evaluation methods. Journal of Systems and Software 79(6), 871–888 (2006) [11] Bhagwat, S.A., Patterson, K.Y., Holden, J.M.: Validation study of the USDA’s Data Quality Evaluation System. Journal of Food Composition and Analysis 22(5), 366–372 (2009) [12] Brokl, H., Menou, M.J.: Index of information Utilization Potential. Final Report of Phase 2 of the IUP Pilot Porject. GSLIS/UCLA, LosAngeles (1982)
Research on Calculation Method for Agricultural Informatization Contribution Rate Liyong Liu1, Qilong Pan2, and Daoliang Li1,* 1
College of Information and Electrical Engineering, China Agricultural University, 17 Tsinghua East Road, P.O. Box 121, Beijing, 100083, P.R. China [email protected] 2 College of Agricultural Economics and Rural Development, Renmin University of China, P.R. China 100872
Abstract. Informationization is the development trend around the world. In terms of agriculture, it is informationization that the Chinese government takes as a significant strategy in order to solve the ‘agriculture, farmer and village’ problem. Focusing on how to measure the contribution of agricultural informationization to economic growth, this paper explores several key issues in current literatures and summarizes the latest debates in respects of the concept of agricultural informationization, the evaluation method of agricultural informatization, and the calculation method of contribution rate of agricultural informationization to economic growth. This paper finally argues that further research is urgently needed for the contribution rate of agricultural informationization to economic growth due to the existing literature gap regarding the research scope, calculation method, informationization’s impact on agriculture itself, and the practice. Keywords: agricultural informatization, contribution rate, index system, calculation.
1 Introduction Agricultural informatization contribution rate refers to the proportion of algebraic summation in agricultural informatization contributed to in various production elements, or refers to the proportion of role played by agricultural informatization to the agricultural economic growth, and total agricultural output or total value of farm out-put are often used to state agricultural economy level. Agricultural informatization contribution rate will be an important comprehensive index that reflected agricultural informatization’s function and role in agricultural production efficiency growth and agricultural economic development, and will also be an important index that reflected agricultural production mode and production level. Agricultural informatization contribution rate is still a new concept. Through consulting relevant literature in China and abroad, "informatization contribution rate ", Agricultural informatization contribution rate and their *
Corresponding author. Tel.: +86-10-62736764; Fax: +86-10-62737741.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 735–741, 2011. © IFIP International Federation for Information Processing 2011
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theoretical frontiers for calculation could be grasped well, and it is of great significance to understand scientifically agricultural informatization contribution rate and to further explore the calculation method which suits Chinese condition well. There are several key problems needing to be solved when researching calculation method of agricultural informationization contribution rate. The first one is the definition of the concept and category of informatization and agricultural informatization. The second is measurement method of informatization and agricultural informatization level. The third one is measurement methods of the contribution rate of informatization to economic growth. The last one is the application of all measurement methods in agricultural informatization contribution rate. There has been much research on the aspects mentioned above, which provides study foundation for further work. So this paper mainly focuses on the summary and analysis of relevant literature in China and abroad.
2 Research about the Concept and Connotation of Agricultural Informatization For the concept of the agricultural informatization, there has not been made an authoritative explanation in theory. Chunjiang Zhao (2007) pointed out that agricultural informatization is a process, which, in human agricultural production activities and social practice, promotes agricultural economy development and the rural social progress by way of high-tech such as communications technology and information technology to efficiently make use of information resources. Shihong Liu (2005) pointed out agricultural informatization is a rural and agricultural integrated system including agricultural resources and environment informatization, rural social and economic informatization, agricultural production informatization, agricultural science and technology informatization, rural education informatization and agricultural production material and production management informatization. Fangquan Mei (2007) thinked agricultural informatization is a generalized concept, which is the wide application of information technology and information management in rural areas and should be informatization of agricultural overall process, and at least six fields, those are the informatization of rural life and consumption, the informationization of agricultural production management, the informationization of rural science and technology, the informationization of rural operation and management, the informatization of rural market circulation, and the informatization of rural resources and environment, should be included. Based on former research and some relevant conclusion, Daoliang Li (2008) and his team, make agricultural informatization as following definition: Agricultual informationization refers to a degree and process which modern information technology can be applied in rural production and business operation, rural public service, government management and daily consumption and other aspects through enhancing rural information infrastructure construction, such as broadcast networks, telecommunication network and computer network, fully developing and utilizing of information resources, structuring information service system, promoting information communication and knowledge sharing.
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3 Research on Agricultural Informatization Level Measurement It is very different about the period, ways, speed and types of agricultural informatization around the world. In developed countries, study on agricultural informatization level measurement earlier was proceeded very early and have formed several mature development systems, which includs evaluation system. In the middle of 1980s, UNESCO proposed to use information utilization potential index method, and have done some practical measurement research (BroklH,Menou M.J. ,1982). In 1982, America's B.K. Eers used three-factors multiple-parameter model to analyze 87 underdeveloped countries’ correlation of information activities with the social and economic development (Eres B k. 1982). Vijay S and William R K (1994) started wiht obtaining the competitive advantage and proposed evaluation index system of the enterprise's informatization, which included seven factors, totally twenty-nine indices. Ravi 1999 et al. started with keeping the competitive position and proposed to use 15 2nd indices to subdivide 1st index (key competition point) and to evaluate the enterprise informatization. In order to evaluate enterprise informatization from the angle realizing the strategic objectives, Nagalingam 1997 used multiple-target comprehensive evaluation method and divided every strategic objective into several operational sub-objectives, which formed evaluation index system to be used in expert system. Under the condition of keeping China national informatization index system and Beijing informatization statistic index system identical and according to information basic elements and principles to establish evaluation index system, Anxiang Lu, Yunlong Zhao, Xiangyang Qin, Zhihong Ma 2006 et al. proposed six aspects, from information resources development, informatization talents, construction of information network, application of information technology, consumptive level of information, and development level of information industry, including 19 indices to evaluate of rural informatization ( Table 1) .
( )
( )
( )
Table 1. Agricultural informatization level evaluation index system (Anxiang Lu, et al. 2006) No. Index 1 Average hours radio and television broadcast per day 2 Internet users per ten thousands person
Unit Hours/day Families/ 10000 persons 3 bandwidth possession Per capita KB/ person 4 quantity of university students per ten thousands person Persons/ ten thousands person 5 Computer ownership rate per 100 Family Sets/100 Family 6 Lines of main toll route per 100 persons for fixed telephones Lines/100 Family 7 quantity of mobile phones per hundred person Sets/100 person 8 Rate of cable TV to premises % 9 The village owning cable rate (rate of the optical fibre cable to % village) 10 Broadband households rate(rate of broadband to premises) % 11 Information index %
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Table 1. (continued) 12 Quantity of computer per hundred students, including college, middle school student 13 Proportion of enterprises using internet enterprises to total enterprises 14 Cable's length per 100 square kilometers
Sets/100 person
% Core kilometers /100km2 G % % %
15 16 17 18
total capacity of network resource database E-commerce transaction rate Rate of Information industry added-value to GDP proportion of fixed investment in information industry to fixed investment in whole society 19 Proportion of the expenses for information industry research and development to the expenses for whole social research and development
%
4 The Study of Calculation Methods of Informatization Contribution Rate to Economic Growth The theory of informatization measurement was originally proposed by American economists Fritz Machlup in his American Knowledge Production and Distribution in 1962. This measureing method is very wide, all-embracing in range, involving in various fields of intellectual industry. On the basis of Machlup, M Poratm in 1977 put forward a new method system which is operative. The theory thinks that the development of information economy mainly depends on the development of two great information departments. The first department is that directly produces information and knowledge and then processes it. The second department is that consume information, namely all the the governments consuming information service and non-information enterprise. M Poratm thought that the second information department plays an important role in information economy. For information economic input-output analysis, M Poratm put forward a set of theories and methods of compiling information input-output table according to general input-output data, and used US national statistic data to concretely measure the employment and GNP value of information economy in US, which firstly makes people have a clear understanding to America's economic structure and nature. Japanese economists Komatsu Kiyoshi in 1965 put forward informatization index method. This informatization index model is composed of 4 second indices and 11 third indices, including information amount (indirectly to show information equipment level and development level of information services’ industry), information equipment rate, communication body level (personnel structure and the third industry development level), information coefficient (consumer’s input besides the basic living expenses) and so on. This method is simple and easy to operate and has been widely used in many countries including China.
.
.
.
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Compared with the developed countries, it is very late in China to study informationization. In the middle of 1980s China began to research on information theory and informatization level measure theory and methods. In 1997 Informationization Work Leading Group of the State Council put forward the definition of national informatization firstly. When measuring informatization level in China, combining with China's specific situation and fully absorbing foreign existing scientific evaluation methods, Chinese scholars put forward some Chinese characteristic calculation methods of information contribution rate to economic growth. Youping Zhu 1996 used C-D Function to carry out regression analysis with Chinese real GDP data from 1980 to 1992 and information, capital and labor elements. The results showed that the information elements’ contribution is the highest to the national economic growth (coefficient is 0.841597), the following one is labor elements (coefficient is 0.697838), and the last is the capital (coefficient is 0.255566). Based on output-growth production function, Dongqiang Guo, Zhijiang Wang (2000) put forward a mathematic model, which can measure contribution rate of informatization input to enterprise output growth, and provide theory basis for the quantitative evaluation of enterprise informatization’s construction. According to Cobb—Douglas production function, Hua Zhou (2009) constructed a production function model which based on the informatization input. He took 54 electrical manufacturing enterprises informationization data in Fujian province from 2004 to 2006 as sample, and applied panel data analysis method to measure the output contribution coefficient of informatization.
(
)
5 Research on Measuring Method of Agricultural Informatization Contribution Rate Although there is amount of research in the measurement of contribution rate of informatization to economic growth in China and abroad, which accumulated much theory and a number of methods, and provides important reference for further research, From literature retrieval there is no statement of Agricultural informatization contribution rate up to now and study on contribution of agricultural informatization to agricultural economic growth is also very little. Xinran Zhao (2006) did a preliminary discussion of agricultural informatization input and output by way of cobb-douglas production function method in her master thesis, And the evaluation index of contribution of information input to agricultural economic growth was calculated by using the result of regression analysis. Whether for the establishment of agricultural informatization evaluation system, or for construction of C-D production function, the argumentation for variable selection is still insufficient, leading to the lack of scientificity in conclusion and the vagueness of the concept of agricultural informatization. In addition, there is no directly relevant literature about agricultural informatization contribution rate. It is obviously a new research field to study the calculation method of agricultural informatization contribution rate.
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6 Conclusion To sum up, agricultural informatization contribution rate, as a comprehensive index reflecting the function of agricultural informatization in agricultural production efficiency and agricultural economic growth,, is still a new concept in academia. There is few direct research literature, and the research on theory and method is very short. But there is amount of research focusing on the informatization and measurement of agricultural informatization level, contribution rate of informatization to economic growth, which provide great foundation and many references to further study in theories and methods. Nonetheless, in those studies, there are still some problems needing to be solved. It is mainly in the following respects. (1) As for the definition and concept of informationization, many definitions are basically limited to country, region. There are almost no statements on agricultural informatization or rural informatization abroad and most research are about the application of information technology in agriculture. Agricultural and rural informationization is an unique vocabulary under existing situation in China. The research scope of agricultural informatization is broad with different versions. Therefore, the principal task of research on agricultural informatization contribution rate is to clear the concept, connotation and extension of agricultural informatization based on the theory and practice in China and abroad. (2) Although in the world there are dozens of methods of the informatization level measurement and analysis, the more common methods are Porat's method and the social informatization index model suggested by Japanese scholar, and both of them have their own advantages and disadvantages. Porat's method is a macro measure way, fitting for a national and social informatization, but it is not fit for agricultural informatization level measuring, because in China the concept of agricultural information industry is not clear. Japanese informatization index model neglectes the function of knowledge production department and information production department, which are very crucial in Porat's method. Informatization index method uses arithmetic average, which covers up some substantive difference. With the development of the times, the indices have seriously outdated, being hard to reflect the development trend and the latest achievements in informatization. In future, the research on index selection of agricultural informatization level measurement must fully consider the modern information technology development situation, such as the agricultural information technology application and promotion, etc. (3) In the impact of informatization on economic and social development, existing research mainly concentrated on the impact of informatization on national economy, the difference of informatization level and informatization contribution rate between different countries, enterprise informatization and its benefit, etc. The research of contribution of informatization on agricultural development is very pool. Especially there are few studies on contribution rate of different informatization indices to agricultural development, leading to the shortage of scientific guidance when evaluating the efficiency of agricultural informatization construction. (4) In the aspects of agricultural informatization level measurement and informatization contribution rate, most studies didn’t deeply analyze the relationship and
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reciprocal influence between the informationization level and the efficiency difference, and couldn’t provide feasible suggestions for national strategy and policies or measures. When trying to measure the contribution rate of agricultural informatization, it should pay much attention to the practical operation of informatization construction in future research.
Acknowledgements The authors thank Ministry of Agriculture of People’s Republic of China for it’s financial support.
References [1] Brokl,H., Menou, M.J., Index of information Utilization Potential. Final Report of Phase 2 of the IUP Pilot Porject. GSLIS/UCLA, LosAngeles (1982) [2] Eres, B.K.: Economic conditions report to informationactivity in less developed countries. [3] Nagalingam, S.V., Lin, G.C.I.: A unified approach towards CIM justification. Computer Integrated Manufac-turing Systems 2, 133–145 (1997) [4] Ravi, K., Murugan, A., Magid, I.: Selecting IT applications inmanufacturing: aKBS approach. Omega 27(2), 605–616 (1999) [5] Vijay, S., William, R.K.: Development of measures to as-sess the extent towhich an information technology appli-cation provides competitive advantage. Management Science (12), 1601–1627 (1994) [6] Guo, D.Q., Wang, Z.J.: Discussion of contribution in enterprise production growth of informatization construction input. Maragement infomoation system (10), 36–38 (2000) [7] Li, D.L.: China’s rural informatization development report 2008. China’s publishing house of electronics industry, Beijing (2008) [8] Liu, S.H.: Information technology in agriculture and rural informatization. China’s agricultural science and technology publishing house, Beijing (2005) [9] Lu, A.X., et al.: Research on rural informationization measuring index system. Agricultural information network (12) (2006) [10] Mei, F.Q.: Agriculture and rural information service: the diversification, the socialization and networking. China information times (4), 15–22 (2007) [11] Zhao, C.J.: Rural informationization technology. China’s agricultural science and technology publishing house, Beijing (2007) [12] Zhou, H.: A empirical research on contribution of manufacturing enterprise informatization to the output contribution. Hainan university journals (humanities and social science edition), (3) (2009) [13] Zhu, Y.P.: Discussion of informatization influence on economic growth. Informatics journal (5), 5–8 (1996)
An Empirical Research on the Evaluation Index Regarding the Service Quality of Agricultural Information Websites in China Liyong Liu, Xiaoqing Yuan, and Daoliang Li* College of Information and Electrical Engineering, China Agricultural University, 17 Tsinghua East Road, P.O. Box 121, Beijing, 100083, P.R. China [email protected]
Abstract. Agricultural information website, which takes the mission of providing valid information for the expansive agricultural information demanders, is an important carrier for the state to enact its strategy of agriculture informatization. This paper establishes a set of evaluation measures regarding the service quality of agricultural information websites by setting up the index system of agricultural information websites, evaluates comprehensively agricultural information websites in the following four respects: the range of content, the operation, the benefits and the costs, and finally conducts an empirical research on 13 agricultural information websites in China to test and justify these measures. Keywords: agricultural information website, information service, evaluation, index system.
1 Introduction According to Gu Shen and An Baojun (2005), an agricultural information website should have agriculture industry as its main content; or both its target client and its main content or service involve agriculture industry. The website itself should at least meet one of these three requirements: (1) a website with independent domain and host server; (2) an independent website using webhost if without independent domain; (3) a website with virtual directory and independent complete information system if without independent domain or host server (Hu Dehua, Wang Jinhua, 2007).
2 The Evaluation Index System 2.1 Constructing Evaluation Items Constructing evaluation items lays the basis for designing the evaluation index system of agricultural information websites. In accordance with the characteristics of agriculture websites, by breaking down the evaluation aims, four first-class evaluation *
Corresponding author. Tel.: +86-10-62736764; Fax: +86-10-62737741.
D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 742–750, 2011. © IFIP International Federation for Information Processing 2011
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indexes can be established: the range of content, the operation, the benefits and the costs (Jia and Zhao, 2003); then sixteen second-class indexes can be established, such as the practicability, comprehensiveness, the accuracy, etc.; and finally thirty third-class indexes, such as satisfying the real demand for agricultural information (Li, 2008), targeting recipients, click rate, etc. 2.2 Distributing the Weight of Indexes Among the first-class indexes, the range of content should be considered as the primary factor during the evaluation process, and the operation should be the second one. The benefits should be the third one due to the effectiveness and development consideration while evaluating the quality of websites. In addition, because of the development cost issue of websites, the cost should be regarded as the fourth factor. The weight of both the first-class indexes and the second-class indexes is decided through expert evaluating method and the results are shown in the table 1: Table 1. The content and weight of first-class and second-class indexes First-class
Second-class Practicability 0.3
Comprehensiveness 0.2 The range of content (0.4)
Accuracy 0.25 Authority 0.05 Timeliness 0.05 Specificity 0.05 Stability 0.1 Navigation design 0.3 Resources organization 0.2
The operation (0..3)
User interface 0.2
Search function 0.15 Connectivity 0.15
Third-class Satisfying the real demand for agricultural information Targeting recipients Effectiveness level Variety of agricultural information Depth of agricultural information Availability of original document Objectivity Information standards Reliability Reputation of information providers The longest update cycle distinctiveness Providing information stably Opening speed of the website Internal linkage Relativity of the linked resource Categories in terms of agricultural subjects Balance of all kinds of agricultural information resources Menu design User interface User guide and help information Search method Search speed Search range Response speed Download speed
Weight 0.5 0.3 0.2 0.5 0.35 0.15 0.6 0.4 0.6 0.4 1.0 1.0 0.6 0.4 0.55 0.45 0.5 0.5 0.4 0.35 0.25 0.4 0.25 0.35 0.5 0.5
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The benefits (0.2) The costs (0.1)
Interactivity 0.5 Effectiveness 0.5 Technical support 0.5 Connection cost 0.5
Registration, forum (global) click rate Software and hardware requirements Connection fee
1.0 1.0 1.0 1.0
2.3 Three Levels of Grading Standards Evaluation objects can be rated into four levels as A, B, C, and D, each level is given different score scale. Therefore the evaluation criteria of websites are refined greatly. As shown in table 2, such a method is simple and clear and easy to operate. Table 2. Three levels of grading standards
Three levels of grading
A
B
C
D
Score scale
90-99
70-89
60-69
40-59
2.4 Grading Criteria of Evaluation Objects (Agriculture Websites) Criteria of preparing index system refers to grading requirements for defining evaluation indexes. The evaluation system is divided into four levels: A (91.00 – 100.00), B (81.00 – 90.00), C (71.00 – 80.00), and D (40.00 – 70.00), the scale of each level will be determined, and the evaluation results will be calculated by corresponding mathematical formula.
3 Evaluation Method 3.1 Mathematical Modeling of Evaluation Indexes The overall objective of evaluation can be embodied in evaluation indexes which include sub-objectives (major evaluation respects) and factors (evaluation items). The series of index sets constitute the evaluation index system. The mathematical relation of the overall evaluation objective, sub-objectives and evaluation factors, namely the structure of the evaluation index system, is illustrated by the DirectionalTree Graph as shown in Chart 1 (Zhou, 2006). In Chart 1, Z refers to the evaluation object, which is the ultimate question solved by the evaluation system; F refers to the range of content in the first-class indexes; S is the operation in the second-class indexes (The benefits and costs are left out since this chart in this article is only for the purpose of brief explanation). DirectionalTree can be
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Chart 1. DirectionalTree Graph
mastered quickly and easily applied to concrete problems as it is a simple and manifest calculation model solving this kind of mathematical problems, its calculation process is easy to understand (Yang, Liu and Wang, 2009). Taking DirectionalTree’s advantages above, we analyzed and calculated agricultural information websites by this model, and got the final results. 3.2 Analyzing and Calculating Process 3.2.1 Parameters Description Z The overall index Zi first-class indexes(Z1,Z2,Z3) Zij second-class indexes(Z11—Z1n,Z21—Z2n,Z31—Z3n) Zijk third-class indexes(Zij1—Zijn,Zi1k—Zink,Z1ik—Znjk) α: Level correction factor(αA:0.0101,αB :0.0112,αC :0.0139,αD : 0.0145)
: : : :
NOTE: Considering the impact of the evaluator’s subjective factors, we magnify the evaluation results properly and determine α in the following way: the full score of each level is presumed as a, then α = a/(a-1)-1. β: weight of indexes on each level 3.2.2 Calculation Process Step 1: Zij = ∑Zijk•βijk Step 2: Zi= ∑Zij•βij =∑∑Zijk•βijkβij Step 3: Z=α∑Zi •βi =α∑∑∑Zijk•βijkβijβi
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4 The Empirical Calculation of the Model 13 agricultural information websites are selected for empirical research in this paper, which are: China Agriculture Web, Zhongshan Agricultural Information Web, China Livestock and Veterinary Web, China Forage Industry Information web, China Fruits web, China Agricultural Products Information Web, China Agricultural Products Information Window, Chengde Agricultural Information Web, China Plant Industry Information Web, Chinese Academy of Agricultural Sciences, Wanquan Agricultural Information Web, Zhengding Agricultural Information web and Shiji Rural Information Web. The scores and rank are listed in table 3, table 4 and table 5 as below. Table 3. Scores of agricultural information websites based on second-class indexes Website Index 1
2
3
4
5
6
7
8
9
10
11
12 13
Practicability
28.53 27.00 29.37 29.07 28.17 28.56 28.41 27.96 28.20 27.60 26.76 27.42
27.24
Comprehensiveness
18.84 14.80 19.24 18.61 14.43 19.26 17.71 18.82 16.60 18.23 17.51 17.68
17.90
Accuracy
24.10 21.25 24.05 24.30 21.25 26.65 22.75 22.80 23.75 23.45 24.45 22.95
21.30
Authority
4.70
4.15
4.86
4.55
4.06
4.75
4.12
4.480 4.50
4.83
4.57
4.30
4.56
Timeliness
4.90
4.45
4.95
4.95
2.95
4.95
4.90
4.950 4.25
4.25
4.75
4.75
4.70
Specificity
4.75
3.25
4.45
2.95
3.15
4.90
4.50
4.450 4.75
4.40
4.65
4.70
4.65
Stability
9.48
8.90
9.80
9.52
4.98
9.12
8.98
9.26
9.54
9.32
9.34
9.24
Navigation design
28.34 27.83 28.97 28.91 26.76 26.67 22.50 27.69 24.52 27.83 26.57 26.25
27.83
Resources organization
19.00 17.00 19.40 18.70 17.20 18.7
19.00 19.50 15.00 17.60 18.00 14.40
17.60
User interface
19.60 17.21 17.36 12.52 14.02 19.31 19.50 17.07 17.69 17.50 16.00 17.37
17.90
Search function
14.55 13.96 14.48 14.65 8.39
13.64 13.31 8.85
12.44 13.29
13.85
Connectivity
13.65 11.63 12.53 12.38 7.88
11.03 8.78
11.85 10.50 13.88 11.03 13.80
13.80
Interactivity
49.00 47.00 34.50 49.00 47.50 49.50 48.50 29.50 45.00 29.50 29.50 40.00
46.00
Effectiveness
48.00 44.50 49.00 48.50 42.50 44.50 41.00 32.50 48.00 46.00 45.00 34.50
42.50
Technical support
46.50 47.50 47.50 48.50 46.00 46.00 45.00 47.50 40.00 47.00 45.00 47.50
47.50
Connection cost
47.00 47.50 47.50 48.50 47.50 46.00 45.00 47.50 45.00 47.50 45.00 47.00
47.50
9.50
13.46 8.85
Note: 1 China Agriculture Web, 2 Zhongshan Agricultural Information Web, 3 China Livestock and Veterinary Web, 4 China Forage Industry Information web, 5 China Fruits Web, 6 China Agricultural Products Information Web, 7 China Agricultural Products Information Window, 8 Chengde Agricultural Information Web, 9 China Plant Industry Information Web, 10 Chinese Academy of Agricultural Sciences, 11 Wanquan Agricultural Information Web, 12 Zhengding Agricultural Information Web, 13 Shiji Rural Information Web.
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Table 4. Scores of agricultural information websites based on the first-class indexes The range of content 38.12
Index The operation 28.54
The benefits 19.4
The costs 9.35
Zhongshan Agricultural Information Web
33.52
26.29
18.3
9.5
China Livestock and Veterinary Web China Forage Industry Information Web
38.69
27.82
16.7
9.5
37.58
26.15
19.5
9.65
China Fruits Web
31.6
22.28
18
9.35
39.28
26.8
18.8
9.2
36.55
24.92
17.9
9
37.09
25.49
12.4
9.5
36.62
17.00
18.6
8.5
36.92
25.7
15.1
9.45
Website Chsina Agriculture Web
China Agricultural Products Information Web China Agricultural Products Information Window Chengde Agricultural Information Web China Plant Industry Information Web Chinese Academy of Agricultural Sciences Wanquan Agricultural Information Web
36.81
25.23
14.9
9
Zhengding Agricultural Information Web
36.46
25.53
14.9
9.45
Shiji rural Information Web
35.72
27.29
17.7
9.5
Table 5. Overall ranking of agricultural information websites Rank
Website
Score
Grade
1
China Agriculture Web China Agricultural Products Information Web
96.37
A
95.03
A
2 3
China Forage Industry Information Web
94.67
A
4
China Plant Industry Information Web
94.15
A
5
China Livestock and Veterinary Web
93.64
A
6
Shiji Rural Information Web China Agricultural Products Information Window Zhongshan Agricultural Information Web
91.12
A
89.36
B
88.59
B
88.14
B
7 8
10
Chinese Academy of Agricultural Sciences Zhengding Agricultural Information Web
87.31
B
11
Wanquan Agricultural Information Web
86.9
B
12
Chengde Agricultural Information Web
85.42
B
13
China Fruits Web
82.13
B
9
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It is demonstrated by Table 5 that six websites including China Agriculture Web, China Agricultural Products Information Web, China Forage Industry Information Web, China Plant Industry Web, China Livestock and Veterinary Web, and Shiji Rural Information Web all got high scores over 90. Hence they can be classified into A-class agricultural information websites. Particularly, these six websites all have an outstanding performance in terms of the range of content, the operation and can be viewed as the model of rural information websites. However the other seven websites such as China Agricultural Information Window, Zhongshan Agricultural Information Web and Chengde Agricultural Information Web score less. Some specific respects of these websites remain to be improved although they meet the basic needs of rural information demanders. In addition, scores and ranking based on each index are listed in table 6, table 7, table 8 and table 9 below. Table 6. Scores and ranking based on the range of content Ranking
Website
Score
1 2 3 4 5 6 7 8 9 10
China Agriculture Web China Plant Industry Information Web China Livestock and Veterinary Web Shiji Rural Information Web China Agricultural Products Information Web Zhongshan Agricultural Information Web China Forage Industry Information Web Chinese Academy of Agricultural Sciences Zhengding Agricultural Information Web Chengde Agricultural Information Web
28.54 27.84 27.82 27.29 26.80 26.29 26.15 25.70 25.53 25.49
11
Wanquan Agricultural Information Web
25.23
12
China Agricultural Products Information Web
24.92
13
China Fruits Web
22.28
Table 7. Scores and ranking based on the operation Ranking 1 2 3 4 5 6 7
Website China Agriculture Web China Plant Industry Information Web China Livestock and Veterinary Web Shiji Rural Information Web China Agricultural Products Information Web Zhongshan Agricultural Information Web China Forage Industry Information Web
Score 28.54 27.84 27.82 27.29 26.80 26.29 26.15
Evaluation Index Regarding the Service Quality of Agricultural Information Websites Table 7. (continued) 8 9 10
Chinese Academy of Agricultural Sciences Zhengding Agricultural Information Web Chengde Agricultural Information Web
25.70 25.53 25.49
11
Wanquan Agricultural Information Web
25.23
12
China Agricultural Products Information Window
24.92
13
China Fruits Web
22.28
Table 8. Scores and ranking based on the benefits Ranking 1 2 3 4 5 6 7 8 9 10 11 12 13
Website China Forage Industry Information Web China Agriculture Web China Agricultural Products Information Web China Plant Industry Information Web Zhongshan Agricultural Information Web China Fruits Web China Agricultural Products Information Web Shiji Rural Information Web China Livestock and Veterinary Web Chinese Academy of Agricultural Sciences engding Agricultural Information Web Wanquan Agricultural Information Web Chengde Agricultural Information Web
Score 19.50 19.40 18.80 18.60 18.30 18.00 17.90 17.70 16.70 15.10 14.90 14.90 12.40
Table 9. Scores and ranking based on the costs Ranking 1 2 3 4 5 6 7 8 9 10 11 12 13
Website China Forage Industry Information Web China Livestock and Veterinary Web Chengde Agricultural Information Web Shiji Agricultural Information Web Zhongshan Agricultural Information Web China Plant Industry Information Web Zhengding Agricultural Inforation Web Chinese Academy of Agricultural Sciences China Fruits Web China Agriculture Web China Agricultural Products Information Web China Agricultural Products Information Window Wanquan Agricultural Information Web
Score 9.65 9.50 9.50 9.50 9.50 9.45 9.45 9.45 9.35 9.35 9.2 9.00 9.00
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It can be interpreted from these tables that in terms of the range of content, all these websites score relatively equal and most of them is capable of providing real, accurate and comparatively extensive and deep agricultural information. This suggests that Chinese agricultural information websites’ amount and depth of information are increasing annually. In terms of the operation, each website performs well. For instance, China Agriculture Web, China Plant Industry Information Web and China Livestock and Veterinary Web have a reasonable navigation design, evenly distributed resources, friendly user interface and convenient function of search and download while China Livestock and Veterinary Web has a very good navigation design and users can retrieve information clearly as long as they login to the website. As far as the benefits are concerned, users can easily judge which website does well or not since this index has a strong objectivity. For example, Chinese Academy of Agricultural Sciences doesn’t score very due to its lacking of functions of registration, forum and etc. in spite of its favorable impression on users. As for the costs, all of these websites have lower requirements for users’ internet condition and the connection fee of each website is not high either. And these websites would benefit from these to expand their user scope.
5 Conclusion The evaluation method for the service quality of agricultural information websites constructed by this research is a relative scientific and impartial method by establishing the evaluation principles and method and applying to 13 agricultural information websites in random. It does not look at a website only from a single respect nor roughly evaluate a website from all respects. On the contrary, it evaluates the quality of a website based on the most important 30 respects and furthermore it is simple and clear, easy to learn and use, and can be used by anyone on any condition to evaluate a website scientifically and objectively.
References [1] Gu, S., An, B.J.: The Status Quo and Analysis of Agricultural Information Websites Construction in China. Agricultural Network Information (7) (2005) [2] Hu, D.H., Wang, J.H.: The Evaluation of University Library Websites Based on Information Construction Theory. Information Science (2) (2007) [3] Jia, S.G., Zhao, Y.J.: The Status Quo and Analysis of Agricultural Information Website Construction in China. Computer and Agriculture (9) (2003) [4] Wang, X.L.: The Evaluation System of Professional Websites. Information Magazine (10) (2002) [5] Zhou, H.: Constructing the Evaluation System on Information Resources of Medical Websites by Applying Mathematical Model. Medical Information Magazine (3) (2006) [6] Yang, H.Y., Liu, J., Wang, C.Q.: The Application of AHP in the Evaluation of Agricultural Information Websites. Anhui Agricultural Science 37(28), 13940–13942 (2009) [7] Li, D.L.: China’s rural informatization development report 2007. China’s agricultural science and technology publishing press (2007)
Hyperspectral Sensing Techniques Applied to Bio-masses Characterization: The Olive Husk Case Giuseppe Bonifazi and Silvia Serranti Dipartimento di Ingegneria Chimica Materiali Ambiente Sapienza – Università di Roma [email protected], [email protected]
Abstract. Olive husk (OH) quality, in respect of constituting particles characteristics (olive stones and pulp residues as result after pressing), represents an important issue. OH particles size class distribution and composition play, in fact, an important role for OH utilization as: organic amendment, bio-mass, food ingredient, plastic filler, abrasive, raw material in the cosmetic sector, dietary animal supplementation, etc. . OH is characterised by a strong variability according to olive characteristics and olive oil production process. Actually it does not exist any strategy able to quantify OH chemicalphysical attributes versus its correct utilisation adopting simple, efficient and low costs analytical tools. Furthermore the possibility to perform its continuous monitoring, without any samples collection and analysis at laboratory scale, could strongly enhance OH utilization, with a great economic and environmental benefits. In this paper an analytical approach, based on HyperSpectral Imaging (HSI) is presented. HSI allows to perform, also on-line, a full quantification of OH characteristics in order to qualify this product for its further re-use, with particular reference as bio-mass. HSI was applied to different samples of OH, characterized by different moisture, different residual pulp content and different size class distributions. Results are presented and critically evaluated.
1 Introduction Olives can be considered as the most cultivated fruit crop in the world. The Mediterranean region represent one of the most important and the olive production represents not only a source of income but also it plays an important role at environmental and heritage level [1]. The main producers are located in the Mediterranean and Middle East regions providing 98% of the total cultivated surface area and 99% of the total olive fruit production [2]. The world production of olives, for the year 2007, was 17.4 Mt, of which 12.6 Mt came from Europe [3]. Olive oil organoleptic properties, as well as its healthy-diet characteristics, strongly contributed to spread out the consumption all over the world and not only in the Mediterranean areas where it has been consumed for innumerable generations. Olive oil world output in 2007 approached 3 Mt, with the European Union (EU) being the leading producer and consumer, thanks to the substantial contribution of Spain, Italy, Greece and Portugal [3]. D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 751–764, 2011. © IFIP International Federation for Information Processing 2011
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Olives are not only utilized to produce oil, but they can be directly consumed as “table olives”. Table olives annual world production is about 2 Mt, one-third of which comes from the EU, followed by Egypt (20%), Turkey (12%) and a long list of progressively minor producers [4]. The manufacture of olive oil yields, in addition to the actual oil (20%), a semi-solid cake (30%) and an aqueous liquor (50%). The crude olive cake, composed of olive pulp and olive stone. This latter product is usually dried, at 60°C by rotary drums, and then processed, utilizing an extraction process by hexane to recover the residual oil. At the end of the process an olive stone rich material with low moisture content is obtained: the olive husk (OH) [2]. The process currently utilized to produce olive oil are mainly three, that is: i) the discontinuous traditional pressing system, ii) the three-phase continuous process and iii) the two-phase continuous process. The discontinuous process represents the oldest method. A pressure is applied to stacked filter mats, smeared with paste, that alternate with metal disks; a central spike allows the expressed oil and water (olive juice) to exit. The machinery, however, is cumbersome, the process requires more labour than other extraction methods, the cycle is not continuous, and the filter mats can easily become contaminated. In the three-phase continuous process large horizontal centrifuges (decanters) are utilized. The decanters spin at approximately 3.000 rpm. Centrifugal force moves the heavier solid materials to the outside. A lighter water layer is formed in the middle with the lightest oil layer on the inside. Decanters separate the paste into a relatively dry solid, fruit-water, and oil. Water is added to this system to get it to flow through the decanter. A minimum quantity of water is added to separate the solid material better and to retain water-soluble polyphenols as much as possible. The two-phase continuous process works following the same principle as 3-phase decanters except that the solid and fruit-water exit together. No water needs to be added to the 2-phase system. The discontinuous process is being progressively replaced, first by the continuous three-phase system and then by the two-phase system. The two-phase system practically almost doubles the amount of “solid” residue that further presents a limited storage life and high transportation costs. As a consequence, it is not a profitable feedstock for seed-oil extraction, posing a problem of waste disposal [5]. In order to overcome this constraint, some two-phase olive oil industries have implemented a stage for recovering the OH, which is subsequently used as a fuel in bakeries, ceramic plants, as well as in the olive oil and seed-oil mills themselves [6]. Because of its high heating power (heat of combustion of about 4.1 kcal/kg), OH finds application mostly in thermal processes being used for power generation in the electricity sector and for space calefaction in residential and commercial buildings [7]. Alternatively, it can be thermally degraded by pyrolysis and gasification to produce syngas, used as a fuel to produce electricity or steam or as a basic chemical feedstock in the petrochemical and refining industries [8] [9] [10] [11] . In this paper the possibility offered by a new technology, based on HyperSpectral Imaging (HSI) based sensors, and related detection architectures, to perform an evaluation of OH quality in respect of constituting particles characteristics (olive stones and pulp residues as result after processing). OH particles size class distribution and composition play, in fact, an important role for the use of such a kind of product as biomass: both for direct burning and/or for its utilization in digesters for
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the production of gas. The need to develop simple analytical tools able to perform a full quantification of olive husks characteristics addressed to their use as biomasses, not requiring a physical collections of the samples, and their further analysis at laboratory scale, it is quite important to set up handling strategies for a fast and reliable OH quality assessment. The possibility to develop such new marketacceptable characterization procedures could strongly enhance the optimal utilization of this waste product with great environmental advantages.
2 The HyperSpectral Imaging (HSI) HyperSpectral Imaging (HSI), known also as chemical or spectroscopic imaging, is an emerging technique that combines the imaging properties of a digital camera with the spectroscopic properties of a spectrometer able to detect the spectral attributes of each pixel in an image. Thus, a hyperspectral image, is a three dimensional dataset with two spatial dimensions and one spectral dimension. HSI was originally developed for remote sensing applications [12] but has found application in such diverse fields as astronomy [13] [15], agriculture [15] [16] [17], pharmaceuticals [18] [19] [20] and medicine [21] [22] [23]. Some advantages of HSI over conventional true color imaging (RGB), near infrared imaging (NIR) and multispectral imaging (MSI) are outlined in Table 1. HSI based architectures, in addition to spatial information, can provide spectral information in a wide wavelength range for each pixel of the image. Hyperspectral images are, in fact, made up of hundreds of contiguous wavebands for each spatial position of a target studied. Each pixel in a hyperspectral image contains the spectrum of that specific position. The resulting spectrum acts like a fingerprint which can be used to characterise the composition of that particular pixel. Hyperspectral images, known as hypercubes [24], are three-dimensional blocks of data, comprising two spatial and one wavelength dimension (Figure 1). The hypercube allows for the visualization of specific attributes (i.e. physical, chemical, biological, etc.) characteristics of a specific sample, separated into particular areas of the image, since regions of a sample with similar spectral properties have similar “chemical” composition. It is currently unfeasible to obtain information in all three-dimensions of a hypercube simultaneously; one is limited to obtaining two dimensions at a time, then creating a three-dimensional image by stacking the two dimensional “slices” in sequence. There are two conventional ways to construct a hypercube, the first one known as the “staring imager” configuration and the second known as “pushbroom” acquisition. The “staring imager” configuration involves keeping the image field of view fixed, and obtaining images one wavelength after another. Hypercubes obtained using this configuration thus consist of a three-dimensional stack of images (one image for each wavelength examined), stored in what is known as the Band Sequential (BSQ) format. Wavelength in the “staring imager” configuration is typically moderated using a tuneable filter, Acousto-optic Tuneable Filters (AOTFs) and Liquid Crystal Tuneable Filters (LCTFs) are the two most predominantly employed. AOTFs have been used in the construction of commercially available NIR-CI systems [15]. The main advantages of AOTFs are good transmission efficiency, fast scan times and large spectral range. On the other hand, LCTFs show greater promise for filtering of
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Raman images, due to superior spectral bandpass and image quality [16]. “Staring imager” instruments incorporating tuneable filters have found a number of applications in pharmaceutical quality control [9] [17], their lack of moving parts represents an advantage in many situations. Table 1. Comparison of RGB imaging, NIR spectroscopy (NIRS), multispectral imaging (MSI) and hyperspectral imaging (HSI) [13]
Feature Spatial information Spectral information Multi-constituent information Sensitivity to minor components
RGB imaging yes no low no
NIRS no yes yes no
MSI yes low low low
HSI yes yes yes yes
Fig. 1. Example of four land covers identified adopting hyperspectral measurement [http://www.sed.manchester.ac.uk/.../uperu/project4.htm]. On the left a hypercube of data with spatial location given by the x and y axes and spectral information contained along the z-axis is reported. The spectral distribution of the different components that make up that spectrum (along with their physical origin) are shown on the right hand side.
The “pushbroom” [18] configuration is based on the acquisition of simultaneous spectral measurements from a series of adjacent spatial positions, this requires relative movement between the object and the detector. Some devices produce hyperspectral images based on a point step and acquire mode: spectra are obtained at single points on a sample, then the sample is moved and another spectrum taken. Hypercubes obtained using this configuration are stored in what is known as the Band Interleaved by Pixel (BIP) format. Advances in detector technology have reduced the time
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required to acquire hypercubes. Line mapping instruments record the spectrum of each pixel in a line of sample which is simultaneously recorded by an array detector; the resultant hypercube is stored in the Band Interleaved by Line (BIL) format. This method is particularly well suited to conveyor belt systems, and may therefore be more practicable than the former for industry applications. The HSI detection architecture that has been utilized in the experimental tests reported in the following, belongs to this class of instruments. Table 2. Technical characteristics of the ImSpector™ V10E
Sensor Spectral range Spectral resolution Smile Keoneyst Entrance slit Image size Numerical aperture
Illuminant
- 2/3” CCD Array 780x580, - firewire digital output, - pixel resolution: 12 bit. 400 – 1000 nm 2.8 nm < 1.5 μm < 1 μm 30 μm x 14.2 μm 6.5 mm x 14.2 mm F/2.4 - anodised Aluminum cylinder, - Barium sulfate internal coating, - d/O illumination and viewing conditions, - adjustable height and distance, - 150 W cooled halogen lamp, - stabilised power source.
2.1 HSI Architecture, Equipment and Set Up Pushbroom HIS bases architecture is typically constituted by the following units: optics, spectrograph, camera, acquisition system, translation stage, energizing source (illumination) and computer (Figure 2). The characteristics of the camera, the spectrograph and the illumination conditions determine the spectral range of the detection architecture. A VIS-NIR system, on of the most utilized, typically ranges between 400 and 1000 nm, and utilize Charge Coupled Device (CCD) cameras or Complementary Metal Oxide Semiconductor (CMOS) sensors. Longer wavelength systems require more expensive IR focal-plane array detectors with appropriate spectrograph which operates in the IR region. The sample/target is usually diffusely illuminated by a tungsten-halogen or LED source. A line of light reflected from the sample enters the objective lens and is separated into its component wavelengths by diffraction optics contained in the spectrograph. A two dimensional image (spatial dimension-wavelength dimension) is then formed on the camera and saved on the computer. The sample is moved past the objective lens on a motorized stage and the process repeated. Two dimensional line images acquired at adjacent points on the object are stacked to form a threedimensional hypercube which may be stored on a PC for further analysis.
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The acquisition device utilised in this study is a ImSpector™ V10E operating in the spectral range of 400-1000 nm with a spectral resolution of 2.8 nm. The details of the acquisition architecture are reported in Table 2. The device is fully controlled by a PC unit equipped with the Spectral Scanner™ v.2.3 (SSOM, 2008) acquisition/preprocessing software. The spectrograph is constituted by optics based on volume type holographic transmission grating [20]. The grating is used in patented Prism-Grating-Prism construction (PGP element) characterized by high diffraction efficiency, good spectral linearity and it is nearly free of geometrical aberrations due to the on-axis operation principle. A collimated light beam is dispersed at the PGP so that the central wavelength passes symmetrically through the grating and prisms and the short and longer wavelengths are dispersed up and down compared to central wavelength (Figure 3).
Fig. 2. Architecture set-up utilized to perform a progressive and continuous surface spectra acquisition
A digital image is thus acquired: each column represents the discrete spectrum values of the corresponding element of the sensitive linear array. Such an architecture allows, with a “simple” arrangement of the detection device (“scan line” perpendicular to the moving direction of the objects) to realize a full and continuous control (Figure 2).
\ Fig. 3. Operating principle of ImSpector™
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A line lighting, as energizing source with uniform spatial distribution, was used. Calibration was performed in three steps: i) spectral axis calibration with spectral lamps; ii) dark image acquisition and iii) measurements of “white reference image”. After the calibration phase: i) the image spectra is acquired and ii) the reflectance (Rci) (at wavelengths i and spatial pixels c of interest) is computed:
R ci = [(sample)ci − (dark )ci ] [(white)ci − (dark )ci ]
(1)
such a procedure enables to compensate the offset due to CCD dark current and separates the sample reflectance from the system response.
3 Experimental 3.1 Sample Set Selection Different OH samples, coming from the same oil-waste mill products have been collected. Each sample was characterized according to OH utilization as bio-mass. Moisture content, as well as size class distribution, were thus determined for each sample. Playing both the attributes a preeminent role in the combustion process. HSI based investigations have been then carried out, on the same samples, to verify the possibility to utilize this technique to derive OH moisture and size class distribution characteristics, directly looking at OH flow streams as resulting from an oil mill and/or fed to a thermal process. Furthermore the hyperspectral approach was applied to perform a quality control of OH according to its composition, that is relative presence of olive stones, pulp, olive peel and leaves inside the OH. All the efforts have been thus addressed to develop and set up strategies able to reduce analytical costs improving the speed of the analytical controls and/or to simplify the procedures in terms of possible on-line implementation of fast and robust classification procedures oriented to develop innovative quality control strategies as well as innovative OH certification criteria. 3.2 Spectra Acquisition, Detection and Analytical Logics Implementation Spectra related to the different investigated samples were collected adopting the acquisition architecture previously described (Figure 2). Such a strategy was adopted because it mimics, at laboratory scale, the real behaviour of the control architecture at industrial scale, that is, the progressive and continuous horizontal translation of the sample and the “synchronized” acquisition of the spectra at a pre-established step, allowing this way a tuning of the detection/inspection frequency of the OH. Analyses have been performed to verify the fulfilments of different goals, that is: 1st goal: the possibility to identify specific spectral attributes for each of the OH according to their intrinsic chemical-physical characteristics. Starting from these information, analysis have been carried out performing a characterization of the “shape” of the entire detected spectra and/or identifying peaks or valley characterising the spectral firm.
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2nd goal: the definition of fast, reliable and robust recognition-classification procedures, based on different logics as: i) specific wavelengths intensity ratio analysis, ii) multiple single band intensity comparison at specific wavelengths and iii) spectral firms correlation, in order to built provisional models able to predict OH moisture content and/or OH size class attributes starting from the collected spectra, allowing this way the possibility to certificate OH in respect of the two previously mentioned characteristics. To reach this latter goal a Partial Least Squares (PLS) regression approach was followed [25] [26] [27] [28] [29]. PLS is a technique that generalizes and combines features from Principal Component Analysis (PCA) and MuLtiple Regression (MLR). It is particularly useful when it needs to predict a set of dependent variables starting from a (very) large set of independent variables.
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PLS regression is related to both Principal Component Regression (PCR) and MLR. PCR finds factors that capture the greatest amount of variance in the predictor (X) variables (e.g. OH detected spectra). MLR seeks to find a single factor that best correlates predictor (X) variables with predicted (Y) variables. PLS attempts to find factors which both capture variance and achieve correlation.
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There are several ways to calculate PLS model parameters. Perhaps the most intuitive method is known as Non-Iterative PArtial Least Squares (NIPALS). NIPALS calculates scores (T) and loadings (P) (similar to those used in PCR), and an additional set of vectors known as weights (W) (with the same dimensionality as the loadings P). Using NIPALS, the scores, weights, loadings and inner-coefficients are calculated sequentially. Before comparing the predictive ability of the models, it is useful to review several quality measures. In all of the measures considered, it was attempted to estimate the average deviation of the model from the data. The RootMean-Square Error of Calibration (RMSEC) tells us about the fit of the model to the calibration data. RMSEC is a measure of how well the model fits the data. The RootMean-Square Error of Cross-Validation (RMSECV) is a measure of a model’s ability to predict samples that were not used to build the model. The RMSECV is typically refer to cross-validation experiments, where the existing calibration data set is split into different training and test sets in an effort to assess how a model built using all of the calibration data would perform when applied to new data.
4 Results The analysis of the spectra demonstrates the high selectivity of the proposed approach to assess the presence of moisture in OH, to discriminate about OH product morphometrical characteristics and, finally, to detect the presence of the different constituting elements (olive stones, pulp, olive peel and leaves). 4.1 Olive Husk Moisture Detection The spectral plot clearly shows as the intensity of the spectral response of OH samples is influenced by moisture (Figure 4). Dry samples are characterized, in fact, by higher reflectance in the NIR region between 940 nm and 1000 nm. The opposite is detectable in the VIS region (400-700 nm) and in the NIR region between 700 nm and 940 nm. A multiple single band intensity comparison, at specific wavelengths, can thus be applied to perform the “simple” recognition of OH samples according to their moisture content. The results obtained applying the PLS modelling are reported in Figure 6. In the figure are also reported the trend of the root mean square error related to the calibration phase (RMSEC) (model generation) and the trend of the root mean square error for the validation (RMSECV) (Figure 6.1) performed in the entire investigated VIS-NIR spectra range. From the analysis of the plot (Figure 6.1) it is thus possible to see that after the first five latent variables the RMSECV slightly increases. Such a behavior being related to the “over-fitting” phenomena. Such a phenomenon usually occurs in multiple linear regression (MLR) when the number of factors gets too large, for example greater than the number of observations. In modelling terms it means that the greater is the increase of the RMSECV, the higher is the possibility that the obtained model, even if well fitting the sample data, fails when new data have to be predicted.
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Fig. 5. Olive husk (OH) size class samples average reflectance spectra in the VIS-NIR field (400-1000 nm), as detected by the HSI architecture
4.2 Olive Husk Morphometrical Characteristics The results show as the HSI approach is able to perform a good discrimination of OH morphometrical characterization. The spectral plot (Figure 5) clearly outline as the spectra intensity decreases, decreasing the investigated OH size classes. Such a behaviour is detectable in the entire investigated wavelength range (400-1000 nm), being more marked in the NIR range between 800 nm and 950 nm. As for the moisture a multiple single band intensity comparison, at specific wavelengths, can be carried out in order to perform a “simple” product morphological recognition. In Figure 7 the results obtained applying the PLS modelling are reported. Differently from the moisture case the RMSECV (Figure 7.1) practically remains constant for all the computed latent variables. Starting from OH collected spectra a good predictive model for OH morphometrical attributes can be thus built. 4.3 Olive Husk Composition The HSI allows to perform a full characterization of OH in terms of constituents. The approach is able to well discriminate among olive stones, pulp, olive peel and leaves (Figure 8). The spectra are characterized by different intensity and signature, allowing this way to perform a correct identification of the different constituents. Leaves. They are characterized, in spectral terms, by a signature that is completely different from olive stones, pulp and olive peel. The presence of a “valley” in the spectra in the VIS range (760 nm) allows to perform its detection/discrimination, from the other investigated constituents, just adopting a single band intensity comparison at specific wavelength (760 nm) (Figure 8).
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Fig. 6. Error plot (6.1) in function of the latent variables of the PLS modeling. RMSEC: root mean square error in calibration phase and RMSECV: root mean square error in validation. 6.2: prediction plot of both PLS model and its independent test as it results after olive husk (OH) moisture content spectrophotometric data processing as resulting from the analyses performed in the VIS-NIR (400-1000 nm) wavelengths interval on several OH samples (Ci).
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Fig. 7. Error plot (7.1) in function of the latent variables of the PLS modeling. RMSEC: root mean square error in calibration phase and RMSECV: root mean square error in validation. 7.2: prediction plot of both PLS model and its independent test as it results after olive husk (OH) size class distribution spectrophotometric data processing as resulting from the analyses performed in the VIS-NIR (400-1000 nm) wavelengths interval.
Olive peel. This product is characterized by a spectral response similar to pulp but of a lower intensity. Furthermore in comparison with pulp, and their other constituents, it also presents a lower intensity increase of the spectra in the wavelength range between 550 and 650 nm (Figure 8). Both these aspects can be successfully applied to perform olive peel recognition adopting a multiple single band intensity comparison, at specific wavelengths, or a specific wavelengths intensity ratio analysis. Pulp. Spectra are characterized by an average intensity value, in the wavelength range between 400 nm and 1000 nm, lower than leaves and olive stones and higher than olive peel. Discrimination can be thus performed, in the previous mentioned interval, following single and/or multiple band intensity comparison at specific wavelengths.
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Olive stones. They are characterized by the higher spectral response in the VIS range between 550 nm and 700 nm. In the NIR range their spectral response is quite similar to leaves. Between 830 nm and 840 nm, differently from leaves presenting a progressive increase of the intensity of the spectral response, olive stone spectral intensity practically remains constant (Figure 8). Such a behaviour can be utilized in recognition adopting an intensity-based-gradient-discrimination approach, applied to the described interval, together with a single band intensity comparison, at specific wavelengths (760 nm).
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5 Conclusions The possibility to apply an HyperSpectral Imaging (HIS) based approach to perform a full characterization of olive husk (OH) products addressed to maximize their optimal utilization as bio-masses was experimentally tested. Results showed as the HSI can be considered as an innovative, flexible and low cost tool that, combining imaging and reflectance spectroscopy, can be profitably utilized. More in details, the results obtained on different samples of olive husks (OH), characterized by a different moisture content and different size class composition, allow to well discriminate these attributes. Furthermore the study demonstrated as the procedure is particularly suitable to be utilized to recognize the different OH constituting materials. Such a result is particularly important for a wider utilization of the proposed technique, and the related recognition logics, in other industrial sectors (production of polyols, furfural, olive seed oil, phenol–formaldehyde resins), and/or other applications (utilization of olive-mill waste on degraded agricultural soils, as bio-sorbers activated
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carbon from olive stone, as a plastic filler, as an abrasive, as a metal bio-sorbent, as dietary animal supplementation, etc.) in order to perform a full recovery of olive-mill waste, following different strategies finalized to obtain different marketable products.
References [1] Matosa, M., Barreiro, M.F., Gandinia, A.: Olive Stone as a Renewable Source of Biopolyols. Industrial Crops and Products 32, 7–12 (2010) [2] Niaounakis, M., Halvadakis, C.P.: Olive Processing Waste Management: Literature Review and Patent Survey. Elsevier, Amsterdam (2006) [3] FAOSTAT, Website of Food and Agriculture organization of the United Nations (2009), http://faostat.fao.org/ [4] IOC, Web site of International Olive Council (2009), http://www.internationaloliveoil.org/ [5] Vlyssides, A.G., Loizides, M., Karlis, P.K.: Integrated Strategic Approach for Reusing Olive Oil Extraction by-Products. J. Cleaner Prod. 12, 603–611 (2004) [6] Vlyssides, A.G., Barampouti, E.M.P., Mai, S.T.: Physical Characteristics of Olive Stone Wooden Residues: Possible Bulking Material for Composting Process. Biodegradation 19, 209–214 (2008) [7] Durán, C.Y.: Propriedades Termoquímicas del Arujo de Aceitona. Poder calorífico. Grasas y Aceites 36, 45–47 (1985) [8] Caballero, J.A., Conesa, J.A., Font, R., Marcilla, A.: Pyrolysis Kinetics of Almond Shells and Olive Stones Considering Their Organic Fractions. J. Anal. Appl. Pyrol. 42, 159–175 (1997) [9] López, M.C.B., Blanco, C.G., Martínez-Alonso, A., Tascón, J.M.D.: Composition of Gases Released During Olive Stones Pyrolysis. J. Anal. Appl. Pyrol. 65, 313–322 (2002) [10] Rios, R.V.R.A., Martínez-Escandel, M., Molina-Sabio, M., Rodríguez-Reinoso, F.: Carbon Foam Prepared by Pyrolysis of Olive Stones Under Steam. Carbon 44, 1448– 1454 (2006) [11] Skoulou, V., Swiderski, A., Yang, W., Zabaniotou, A.: Process characteristics and products of olive kernel high temperature steam gasification (HTSG). Bioresour. Technol. 100, 2444–2451 (2009) [12] Goetz, A.F.H., Vane, G., Solomon, T.E., Rock, B.N.: Imaging Spectrometry for Earth Remote Sensing. Science 228, 1147–1153 (1985) [13] Hege, E., O’Connell, D., Johnson, W., Basty, S., Dereniak, E.: Hyperspectral Imaging for Astronomy and Space Surveillance. In: Proceedings of the SPIE, vol. 5159, pp. 380–391 (2003) [14] Wood, K.S., Gulian, A.M., Fritz, G.G., Van Vechten, D.: A QVD Detector for Focal Plane Hyperspectral Imaging. Astronomy. Bulletin of the American Astronomical Society 34, 1241 (2002) [15] Monteiro, S., Minekawa, Y., Kosugi, Y., Akazawa, T., Oda, K.: Prediction of Sweetness and Amino Acid Content in Soybean Crops from Hyperspectral Imagery. ISPRS Journal of Photogrammetry and Remote Sensing 62(1), 2–12 (2007) [16] Smail, V., Fritz, A., Wetzel, D.: Chemical Imaging of Intact Seeds with NIR Focal Plane Array Assists Plant Breeding. Vibrational Spectroscopy 42(2), 215–221 (2006) [17] Uno, Y., Prasher, S., Lacroix, R., Goel, P., Karimi, Y., Viau, A.: Artificial Neural Networks to Predict Corn Yield from Compact Airborne Spectrographic Imager Data. Computers and Electronics in Agriculture 47(2), 149–161 (2005)
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[18] Lyon, R.C., Lester, D.S., Lewis, E.N., Lee, E., Yu, L.X., Jefferson, E.H.: Near-infrared Spectral Imaging for Quality Assurance of Pharmaceutical Products: Analysis of Tablets to Assess Powder Blend Homogeneity. AAPS PharmSciTech. 3(3), 17 (2002) [19] Rodionova, O., Houmøller, L., Pomerantsev, A., Geladi, P., Burger, J., Dorofeyev, V.: NIR Spectrometry for Counterfeit Drug Detection: a Feasibility Study. Analytica Chimica Acta 549(1-2), 151–158 (2005) [20] Roggo, Y., Edmond, A., Chalus, P., Ulmschneider, M.: Infrared Hyperspectral Imaging for Qualitative Analysis of Pharmaceutical Solid Forms. Analytica Chimica Acta 535(12), 79–87 (2005) [21] Ferris, D., Lawhead, R., Dickman, E., Holtzapple, N., Miller, J., Grogan, S.: Multimodal Hyperspectral Imaging for the Non Invasive Diagnosis of Cervical Neoplasia. Journal of Lower Genital Tract Disease 5(2), 65–72 (2001) [22] Kellicut, D., Weiswasser, J., Arora, S., Freeman, J., Lew, R., Shuman, C.: Emerging Technology: Hyperspectral Imaging. Perspectives in Vascular Surgery and Endovascular Therapy 16(1), 53–57 (2004) [23] Zheng, G., Chen, Y., Intes, X., Chance, B., Glickson, J.D.: Contrast-enhanced Nearinfrared (NIR) Optical Imaging for Subsurface Cancer Detection. Journal of Porphyrins and Phthalocyanines 8(9), 1106–1117 (2004) [24] Lu, R.F., Chen, Y.R.: Hyperspectral Imaging for Safety Inspection of Food and Agricultural Products. In: SPIE Conference on Pathogen Detection and Remediation for Safe Eating, Boston, USA (1998) [25] Wold, S., Esbensen, K., Geladi, P.: Principal Components Analysis. Chemo. And Intell. Lab. Sys. 2, 37–52 (1987) [26] Geladi, P., Kowalski, B.R.: PLS Tutorial. Anal. Chim. Acta. 185(1) (1986) [27] Lorber, A.L., Wangen, E., Kowalski, B.R.: A Theoretical Foundation for the PLS Algorithm. J. Chemometrics 1(19) (1987) [28] Martens, H., Næs, T.: Multivariate Calibration. John Wiley & Sons, New York (1989) [29] Höskuldsson, A.: Prediction Methods in Science and Technology. Thor Publishing, Denmark (1996)
Author Index
Ai, Jumei III-721 An, Xiaoyu II-716 An, Zhengguang I-729, I-737 Bai, Jun-Hua II-90, IV-16 Bai, Wei III-92 Bai, Yichuan III-572 Bai, Zhongke III-173 Bao, Jie III-725, IV-610 Bao, Nisha III-173 Bao, Wenxing I-48, II-124, III-132, III-464, III-491 Bi, Chunguang I-312 Bi, Lan IV-450 Bonifazi, Giuseppe IV-751 Cai, Guoyin II-243 Cai, Hongzhen III-341 Cai, Kewen IV-390 Cai, Lecai I-539 Cai, Tijiu II-682 Cao, Hongxin II-441 Cao, Qinghua IV-237 Cao, Qing-Song IV-410, IV-450 Cao, Ran II-322 Cao, Shehua IV-192 Cao, Weixin III-186 Cao, Weixing I-446, II-479 Cao, Wenqin III-14 Cao, YongSheng II-110 Chang, Ruokui III-106 Chang, Zhongle I-590 Chao, Liu II-425 Che, Zhenhua I-569, II-198 Chen, Aixi IV-89 Chen, Baisong II-525 Chen, Baorui I-250, II-658, IV-134 Chen, Bin III-123 Chen, Bing IV-602 Chen, Di-yi II-205 Chen, Guifen I-312, II-408 Chen, Hong II-61 Chen, Hongjiang IV-215 Chen, Hui IV-268 Chen, Jianhua I-569, II-198
Chen, Jin II-607 Chen, Kelou II-139 Chen, Lairong III-532 Chen, Lidong I-359 Chen, Liming II-505 Chen, Ling I-178 Chen, Liping I-103 Chen, Tian’en I-103 Chen, Yaxiong I-390, III-357 Chen, Yongxing III-92 Chen, Zhaoxia IV-63 Cheng, Jianqun IV-361 Cheng, Jihong III-222 Cheng, Jilin II-283, III-554 Cheng, Youping I-149, I-353 Chu, Changbao IV-237 Ci, Xin IV-345 Cohen, Oded I-630 Cui, Hongguang I-267, I-428 Cui, Weiwei II-674 Cui, Yunpeng I-56, II-573, III-648 Dai, Lili I-267, I-428 Dai, Rong II-148 Dan, Nie III-732 Dang, Yv-mei II-726 Deng, Guang I-304 Deng, Hubin IV-96, IV-376 Deng, Jinfeng II-211 Deng, Lei IV-255 Deng, Li II-339, III-390 Deng, Shangmin I-674 Diao, Haiting III-57 Ding, Chao II-11 Ding, Jianjun III-36 Ding, Li I-437 Ding, Qingfeng IV-279 Ding, Qisheng IV-629, IV-642, IV-650, IV-659 Ding, Wenqin I-456 Ding, XiaoLing IV-345 Dong, Jing I-35, II-561 Dong, Jingui I-576 Dong, Lihong IV-231
766
Author Index
Dong, Qizheng IV-167 Dong, Shiyun IV-231 Dong, Sufen II-365 Dong, Yiwei III-92 Dou, Yantao IV-78 Du, Bin IV-355 Du, Huibin I-487 Du, Jing IV-720 Du, Jun I-155 Du, Mingyi I-681, II-243 Du, Shuyuan I-16 Duan, Qingling IV-691 Duan, Qingwei IV-134 E, Yue
II-110
Fan, Honggang I-35 Fan, Shijuan IV-116 Fan, Xinzhong I-576, I-590 Fang, Hui IV-124 Fang, Junlong IV-616 Feng, Shaoyuan II-473 Feng, Yaoze IV-184 Fu, Bing III-186 Fu, Qiang III-419 Fu, Xueliang I-487, I-526 Fu, Yu II-131 Fu, Zetian IV-672, IV-680 Fu, Zhuo II-525 Gan, Weihua II-400, II-579 Gao, Bingbo II-415 Gao, Gaili III-604 Gao, Haisheng IV-355 Gao, Hongyan II-53 Gao, Lingwang I-594 Gao, Miao I-282 Gao, Rui I-138 Gao, Shi-Ju IV-16 Gao, Xiaoliang III-732 Gao, Yang III-539 Gao, Ying IV-260 Gao, Yun I-600, II-61 Gao, Zhi-Fan IV-410 Ge, Daokuo II-441 Ge, Ningning I-594 Geng, Duanyang II-158 Geng, Duayang II-531 Geng, Xia III-1
Geng, Zhi III-710 Gitelson, Anatoly IV-47 Gong, Bikai IV-602 Gong, Shuipeng IV-616 Gong, Yi III-554 Gu, Jingqiu III-661 Gu, Wenjuan IV-543 Gu, Xiaohe I-296 Gui, Dongwei I-321 Guo, Huiling II-18, II-491 Guo, Mingming I-409, III-327 Guo, Qian I-374, III-222 Guo, Rui II-551, III-357 Guo, Wei II-322 Guo, Yuming I-691 Han, Jinyu III-539 Han, Ping I-282, I-290 Han, Qiang I-48 Han, Xiangbo I-16, I-472, I-717 Hannaway, David B. II-441 He, Bailin IV-63 He, Bei I-138 He, Bin II-18 He, Dongxian III-725, IV-504, IV-610 He, Fen II-102 He, Feng IV-8 He, Jianbin I-35, II-561 He, Junliang I-519 He, Lian II-283 He, Pengju II-573, III-648 He, Qingbo IV-206 He, Renwang II-517 He, Tian III-316, III-375 He, Wenying II-551, III-357 He, Yong IV-124 Hu, Chunxia I-238, II-41 Hu, Haiyan I-41, III-158 Hu, Jianping I-401, I-456, I-555, II-496, III-249 Hu, JinYou I-623, III-656 Hu, Juanxiu IV-504 Hu, Kaiqun III-304, III-483 Hu, Lin III-138 Hu, Ping II-30 Hu, Runwen II-667 Hu, Siquan I-131, IV-71 Hua, Yu II-650 Huang, Caojun II-309 Huang, Chong I-582
Author Index Huang, Huang, Huang, Huang, Huang, Huang, Huang, Huang, Huang, Huang, Huang, Huang, Huang, Huang, Huang, Huang,
Guanhua I-643, II-185 Han III-572 Kelin IV-89 Lan III-289 Qing I-250, II-658 Sheng II-351 Wen III-598 Wenjiang I-296, III-280 Xiaomao I-25 Yan II-682 Yanguo IV-321 Ying I-210 Yingsa I-401, I-456, II-496 Yinsa III-249 Yuxiang II-351 Zhigang IV-306
Ji, Baoping III-84 Ji, Ronghua III-304, III-483, III-532 Ji, Ying I-138 Jia, Chaojie I-390, III-357 Jia, Guifeng IV-198 Jia, Shaorong III-198 Jia, Song II-700, III-41 Jiang, Haiyan II-479, III-186 Jiang, Huanyu I-729, I-737 Jiang, Lihua I-149, I-353 Jiang, Na II-473 Jiang, Qiuxiang III-419 Jiang, Wencong II-381 Jiang, Xi II-706 Jiang, Xiangang IV-30 Jie, Dengfei II-118 Jin, Dan III-347, III-445 Jin, Tingxiang I-238, II-41 Jinbin, Li I-335 Jinfu, Lu IV-563 Jinlong, Lin I-608 Juanxiu, Hu III-725 Kai, Wang II-425 Kan, Daohong IV-701 Kong, Fanrang IV-206 Kong, Wenwen IV-124 Kuang, Tangqing IV-543 Lai, Zhigang I-508, IV-361 Lei, Jiaqiang I-321 Lei, Wen I-539 Lei, Xiaojun II-479
Li, Li, Li, Li, Li, Li, Li, Li,
767
Baojun II-30 Biao I-590 Changyou I-487, I-526 Chen III-549 Chengyun I-227, I-335 Chunzhi IV-147 Cunjun I-296, III-280 Daoliang III-725, IV-610, IV-629, IV-642, IV-650, IV-659, IV-672, IV-680, IV-701, IV-710, IV-720, IV-727, IV-735, IV-742 Li, Daoxi II-716 Li, Dapeng II-706 Li, Deying IV-474, IV-514 Li, Fanghua II-682 Li, Fengmin II-551 Li, Gailian I-238, II-41 Li, Gang I-250, II-658, IV-134 Li, Guo IV-691 Li, Guoqing III-241 Li, Haifeng I-321 Li, Hengbin III-379 Li, Honghui I-526 Li, Hongjian IV-89 Li, Hongwen IV-720 Li, Hongyi III-212 Li, Hui I-594, II-317, III-304, III-483 Li, Jia wei IV-39 Li, Jianyun IV-474 Li, Jin III-580 Li, Jing II-90, IV-467, IV-528 Li, Jun IV-382, IV-521 Li, Lin I-35, II-309, II-561 Li, Ling I-698 Li, Linyi II-587 Li, Lixin I-508 Li, Manman III-629 Li, Maogang III-20, III-29 Li, Meian I-487 Li, Minghui IV-514 Li, Mingyong I-576 Li, Na IV-480, IV-537 Li, Peiwu I-600, IV-246 Li, Qiaozhen III-92 Li, Qingji III-413, III-440 Li, Qingqing I-16 Li, Shao-Kun IV-16 Li, Shaokun II-90, II-691 Li, Shijuan I-219, I-261, I-476 Li, Shuqin II-351
768
Author Index
Li, Wei II-102 Li, Wenxin III-572 Li, Wenyue III-598 Li, Xianyue I-155 Li, Xiaoqin IV-294 Li, Xiaoyu I-600, II-61, IV-184, IV-246 Li, Xinlei I-409, III-327 Li, Xuemei II-18 Li, Yan II-185 Li, Yanling II-381, II-392 Li, Yaoming II-607 Li, Yi I-594 Li, Ying III-57 Li, Yong IV-221 Li, Yuan III-500, III-539 Li, Yuanzhang I-68 Li, Yuhong I-275, I-711, IV-575 Li, Yunkai I-155 Li, Yuzhong III-92 Li, Zengyuan I-304 Li, Zhigang III-500, III-539 Li, Zhihong II-465, III-563, III-572 Li, Zhimei III-563, III-572 Li, Zhizhong III-704 Li, Zhongqi IV-177 Liang, Jing II-633 Liang, Qing IV-30 Liang, Yong I-547, II-381, II-392, II-700, III-1, III-41, III-390, III-403, III-452 Liang, Yusheng III-57 Liao, Weichuan II-259 Liao, Xinglong I-1, I-532 Liming, Lu IV-563 Lin, Fengtao IV-568 Linker, Raphael I-630 Liu, Baifen IV-260 Liu, Changju IV-184 Liu, Chengliang II-23 Liu, Cuie III-8 Liu, Cuiling II-317 Liu, Ergen IV-1, IV-390 Liu, Fa I-401, I-456, II-496 Liu, Fei IV-124 Liu, Gang I-138, I-409, III-327, III-580 Liu, Guiyuan IV-96 Liu, Haijun II-185 Liu, Hailong II-290 Liu, Hua III-106
Liu, Jianshu IV-494 Liu, Jianting II-706 Liu, Jie I-600, IV-246 Liu, Jingbo II-415 Liu, Jingyu I-68 Liu, Jingyuan II-465 Liu, Jiping II-674 Liu, Juanjuan IV-108 Liu, Jun III-604 Liu, Junming III-629 Liu, Leping IV-167, IV-333 Liu, Li-Bo I-62 Liu, Lin I-227, I-335 Liu, Liyong IV-727, IV-735, IV-742 Liu, Lu I-623 Liu, Min IV-345 Liu, Mingzeng II-30 Liu, Muhua II-434, IV-467, IV-528 Liu, Ping’ an I-508, IV-361 Liu, Pingan IV-306 Liu, Shengping I-476 Liu, Shihong I-56, II-573, III-158, III-179, III-648 Liu, Shuangxi III-379, III-620, IV-710 Liu, Tao IV-427 Liu, Wei I-178, II-18 Liu, Xiaodong IV-376 Liu, Xiaojun I-446 Liu, Xiuping II-30 Liu, Xu III-289 Liu, Xue IV-672 Liu, Xuming III-704 Liu, Yajuan IV-103 Liu, Yan II-441 Liu, Yande II-1, III-613, IV-427 Liu, Yang I-681, II-243 Liu, Yanqi II-30 Liu, Yin III-327 Liu, Ying II-706 Liu, Yongbin IV-206 Liu, Yongxia II-441 Liu, Yu-xiao II-205 Liu, Zhanli I-472, I-717 Liu, Zheng II-177 Liu, Zhengfang IV-89 Liu, Zhengping IV-108 Liu, Zhifang I-87 Liu, Zhimin IV-89 Liu, Zhipeng I-721
Author Index Liu, Zhongqiang I-76, III-46, III-682, III-696 Long, Changjiang I-25, I-195 Long, Yan II-205 Lu, Anxiang I-282, I-563, II-83 Lu, Daoli III-123 Lu, Gang II-11, III-8 Lu, Huishan I-729, I-737 Lu, Jiahua I-569, II-198 Lu, Peng II-11, II-329, III-8 Lu, Quanguo IV-237 Lu, Shaokun III-725, IV-610 Lu, Weiping I-275, I-711, IV-575 Lu, Yan-Li IV-16 Lu, Zhixiong IV-294 Lu, Zhongmin II-357 Luan, RuPeng II-615 Luan, Xin I-590 Luan, Yunxia II-83, II-457 Luo, Chagen IV-368 Luo, Changshou III-638, III-672 Luo, Chunsheng IV-467, IV-528 Luo, Laipeng IV-1 Luo, Qingyao III-710 Luo, Shimin IV-286 Luo, Xiaoling IV-255 Lv, Jiake III-512 Lv, Xin II-290, II-726 Lv, Yongliang II-706 Ma, Daokun IV-629, IV-650, IV-659 Ma, Hailei I-526 Ma, Juncheng IV-680 Ma, Li II-408 Ma, Liang II-538 Ma, Lili IV-616 Ma, Liuyi II-597 Ma, Lizhen III-106 Ma, Xiaoguang II-465 Ma, Xiao-yi II-205 Ma, Xinming I-437, I-614, II-357, III-269 Ma, Xu I-1, I-532 Ma, Yuan IV-333 Ma, Zhihong I-282, II-83, II-234, III-592 Mao, Enrong III-257 Mao, Hanping II-53 Mao, Shuhua III-721 Mei, Weng II-650
769
Men, Weili I-674 Meng, Haili III-598 Meng, Hong III-158 Meng, Qingyi II-473 Meng, Xianxue III-179 Miao, Pengbo IV-528 Min, Shungeng III-592 Ming, Bo II-691 Mingyin, Yao I-608 Muhua, Liu I-608 Naor, Amos I-630 Ning, Dongzhou IV-376 Ouyang, Aiguo
IV-368
Pan, Fangting III-231 Pan, Guiying II-71 Pan, Jiayi III-710 Pan, Juan I-367 Pan, Ligang I-282, I-290, I-563, II-83, II-234, II-457 Pan, Qilong IV-735 Pan, Yuchun II-525 Pang, Siqin IV-78 Pei, Chunmei II-18, II-491 Peng, Bo I-119 Peng, Cheng II-641, III-661 Peng, Lin I-417 Ping, Hua I-290, II-234, II-457 Ping, Jia III-428 Ping, Xuecheng IV-306 Qi, Kun II-61 Qi, Lijun III-304, III-483 Qi, Limeng II-339 Qi, Long I-1 Qiao, Hongbo II-650 Qiao, Xiaojun III-66, III-75 Qiao, Xibo I-576, I-590 Qiao, Zhong III-473 Qin, JiangLin IV-47 Qin, Xiangyang I-563, III-580 Qing, Chang I-335 Qing, Zhaoshen III-84 Qiu, Wanying II-521 Qiu, Xiaobing III-473 Qiu, Ying IV-420 Qiu, Yun II-300, III-113, III-138 Qiulian, Li I-608
770
Author Index
Rao, Guisheng II-339 Rao, Honghui III-613 Ren, Jiwen IV-494 Ren, Rong III-132 Ren, Shumei I-155 Ren, Souhua II-309 Ren, Wentao I-267, I-428 Ren, Yanna II-357, III-269 Rundquist, Donald IV-47 Serranti, Silvia IV-751 Shang, Huaping II-227 Shao, Xiuping I-401, I-456, II-496 Shao-Wen, Li II-425 She, Chundong I-131, IV-71 Shen, Changjun IV-435 Shen, Lifeng IV-720 Shen, Tao IV-30, IV-592 Shen, Zuorui I-594 Shi, Guoqing III-231 Shi, Liang II-124 Shi, Xiaoxia II-264, II-641 Shi, Yan III-20, III-29 Shi, Yinxue III-367 Shi, Yuanyuan I-614 Shi, Yuling III-289 Shi, Zhou II-71 Shu, Xiaoping IV-521 Si, Yongsheng I-138 Song, Mingyu III-106 Song, Qin I-125 Song, Xiaoqiang III-322 Song, Xiaoyu I-296 Song, Yunliang III-123 Song, Zhenghe III-257 Steele, Mark IV-47 Su, Xiaolu I-41 Su, Yuan I-227, I-335 Sui, Xueyan II-691 Sun, Chao III-36 Sun, Chengli IV-8 Sun, Fa-Xiong IV-450 Sun, Guojun I-390, II-551, III-357 Sun, Jiang I-563 Sun, Jinping III-403, III-452 Sun, Jinying II-441 Sun, Kaimeng II-218 Sun, Li III-198 Sun, Ming IV-39 Sun, Nan II-465
Sun, Sun, Sun, Sun, Sun, Sun, Sun, Sun, Sun, Sun, Sun, Sun, Sun,
Ruizhi III-367 Sufen I-56, III-638, III-672 Suping I-576 Wenbin III-57 Wensheng III-165 Xia I-16 Xiang III-661, IV-583 Xiaoqing II-691 Xudong II-1 Yonghua I-96, I-464 Yongxiang I-547, III-1 Zhiguo I-9 Zhongwei II-329, II-374
Tai, Haijiang IV-642, IV-650 Tan, Feng II-479 Tan, Jinghe I-590 Tan, Jingying III-347, III-445 Tan, Yu-an I-68 Tan, Zongkun IV-47 Tang, Bin IV-89 Tang, Chengwen IV-198 Tang, Liang II-479 Teng, Guanghui III-704 Teng, Guifa II-365 Teng, Yun II-682 Wan, ChangZhao III-222 Wan, Peng I-25, I-195 Wan, Shubo III-146 Wan, ShuJing III-403 Wang, Bai II-682 Wang, Baoqing II-441 Wang, Buyu I-487, I-526 Wang, Changsheng II-30 Wang, Cheng III-66, III-84 Wang, Chun II-345, II-567 Wang, Dong III-592 Wang, Dongqing I-487 Wang, Fang IV-691 Wang, Fang-Yong IV-16 Wang, Fangzhou III-165 Wang, Fei III-198 Wang, Fengxin II-185 Wang, Fuxiang III-563 Wang, Haiguang I-582 Wang, Haiou I-131, III-231, IV-71 Wang, Hongbin I-35, II-561 Wang, Jian I-62, II-415, III-113 Wang, Jianqin I-119
Author Index Wang, Jihua I-282, I-290, I-563, II-83, II-525 Wang, Jing III-249 Wang, Jinhua IV-376 Wang, Jinxing III-379, III-620, IV-710 Wang, Junfeng I-131, IV-71 Wang, Junqiang II-706, IV-592 Wang, Kaili I-643 Wang, Kaiyi I-76, III-46, III-682, III-696 Wang, Ke-Ru IV-16 Wang, Lianzhi IV-629 Wang, Li-jun III-99 Wang, Ling II-290 Wang, Lingyan I-155 Wang, Pu III-491 Wang, Qiang III-269 Wang, Qing III-347, III-445 Wang, Qingchun III-532 Wang, Qiong IV-16 Wang, Ruijuan I-374 Wang, Sangen II-166 Wang, Shengfeng III-428 Wang, Shicong III-473 Wang, Shufeng I-76, III-696 Wang, Shushan III-123 Wang, Shuwen IV-616 Wang, Shuyan I-110 Wang, Susheng I-359 Wang, Wei I-96, I-464, I-600, IV-78, IV-184, IV-246 Wang, Wensheng I-9, I-149, I-203, I-353 Wang, Xi II-567 Wang, Xiangyou I-16, I-472, II-158, II-531 Wang, Xiao IV-467, IV-528 Wang, Xiaojun II-392 Wang, Xiaoli II-623 Wang, Xihua III-36 Wang, Xin I-381 Wang, Xingxing III-20 Wang, Xinzhong II-567 Wang, Xu IV-134 Wang, Xuan III-512 Wang, Yanan III-92 Wang, Yang II-329, II-374 Wang, Yangqiu II-491 Wang, Yanlin IV-514 Wang, Yuanhong III-106 Wang, Yunsheng I-374, II-434, III-222
Wang, Zhaopeng I-576 Wang, Zhenzhi III-46, III-682 Wang, Zhiwei IV-116 Wang, Zhongyi III-289 Wang, Zilong III-419 Wei, Chaofu III-512 Wei, Enzhu III-249 Wei, Lin III-563 Wei, Qingfeng III-638, III-672 Wei, Xinhua II-607 Wei, Xiufang II-441 Wei, Yaoguang IV-642, IV-650 Wei, Yong III-106 Wen, Nannan IV-659 Wu, Chaohui I-275, I-711, IV-575 Wu, Dake II-166 Wu, Dan IV-390 Wu, Ding-Feng I-62, III-113 Wu, Dongsheng IV-382, IV-521 Wu, Hongchao I-576, I-590 Wu, Honggan I-304 Wu, Huarui III-661, IV-583 Wu, Jiajiao III-563 Wu, Jingzhu II-317 Wu, Qingping IV-89 Wu, Qiulan I-547, III-1 Wu, Quan III-198 Wu, Wenbiao III-75 Wu, Xiaoying II-465 Wu, Yali I-691 Wu, Yongchang II-264 Wu, Zhigang III-572 Xi, Junmei IV-237 Xi, Lei I-437, III-269 Xia, Hui I-9 Xia, Junfang II-667 Xia, Lianming II-158, II-531 Xia, Xiaobin IV-8 Xiang, Ling I-290, II-234 Xiang, Quanli I-267, I-428 Xiang, Xinjian I-495 Xiao, Chun-Hua IV-16 Xie, Dandan II-517 Xie, Deti III-512 Xie, Fengyun IV-443 Xie, Nengfu I-149, I-203, I-353 Xie, Rui-Zhi IV-16 Xie, Sanmao IV-314 Xie, Zuqing I-555
771
772
Author Index
Xin, Xiaoping I-250, II-658, IV-134 Xing, Qirong IV-177 Xing, Yajuan I-487 Xing, Zhen IV-435 Xiong, Bangshu IV-8 Xiong, Benhai III-710 Xiong, Guangyao IV-514 Xiong, Guo-Liang IV-410 Xiong, Jinhui I-110 Xiong, Shuping I-614, III-269 Xu, Beili IV-521 Xu, Binshi IV-231 Xu, Chunying III-92 Xu, Fuhou II-597 Xu, Hongmei I-656, I-698 Xu, Jian I-367 Xu, Jianxin III-428 Xu, Li III-473 Xu, Liming II-505 Xu, Ling I-227 Xu, Lunhui IV-321 Xu, Shenghang IV-108 Xu, Shipu II-434, III-222 Xu, Xianfeng IV-63 Xu, XiangBin IV-460, IV-486 Xu, Xiaoli IV-78 Xu, Xin I-437, II-357 Xu, Xingang I-296, III-280 Xu, Yizong I-210 Xue, Fengchang IV-623 Xue, Heru I-502, II-252 Xue, Long IV-403, IV-467, IV-528 Xue, Yan I-219 Xue, Yandong I-155 Yan, Congcong I-472 Yan, Hua III-75 Yan, Jianwu IV-237 Yan, Junyong IV-147 Yan, Lin II-633 Yan, Manfu I-87, I-343 Yan, Qin III-452 Yan, Xiaomei III-620 Yan, YinFa IV-345 Yan, Yuchun IV-134 Yane, Duan II-274 Yang, Chao IV-116 Yang, Deyong I-555, II-496 Yang, Fei III-327 Yang, Feng I-76, III-46, III-682, III-696
Yang, Fengping IV-177, IV-279 Yang, Guixia I-250, II-658, IV-134 Yang, Hao III-280 Yang, Huiying II-185 Yang, Jianhua II-131 Yang, Jing I-227, I-335 Yang, Juan I-374, III-222, III-269 Yang, Le I-569, II-198 Yang, Liang III-710 Yang, Linnan I-417 Yang, Min III-123 Yang, Minghao III-367 Yang, Peiling I-155 Yang, Ping III-413 Yang, Po IV-504 Yang, Sen II-551, III-357 Yang, Shuqin III-428 Yang, Tao III-298, III-322, III-413, III-440 Yang, Wenzhu IV-701, IV-710 Yang, Xiaodong III-280 Yang, Xiaohui II-351 Yang, Xiaorong I-149, I-203, I-353 Yang, Xiaoxia II-700, III-1, III-41 Yang, Xin I-275, I-711, IV-575 Yang, Xiuqing II-18, II-491 Yang, Yafei II-650 Yang, Yang III-316, III-375, IV-398 Yang, Yi I-267, I-428 Yang, Yibo II-517 Yang, Ying I-119 Yang, Yong I-35, I-110, II-561, III-598 Yang, Yongsheng III-464 Yang, Yujian III-146 Yang, Yushu II-322 Yao, Jie II-365 Yao, Shan I-367 Yao, Zhenxuan II-706 Ye, Baoying III-173 Ye, Fan IV-321 Ye, Hairong II-491 Ye, Shengfeng III-592 Yin, Jinju IV-494 Yin, Zhongdong II-538 Ying, Yibin I-729, I-737 Yong, Wang II-650 You-Hua, Zhang II-425 Yu, Feng II-615 Yu, Ligen III-704
Author Index Yuan, Haibo III-20, III-29 Yuan, Jun IV-294 Yuan, Junjing III-341 Yuan, Shengfa I-656, IV-198 Yuan, Tao II-434, II-587 Yuan, Xiaoqing IV-727, IV-742 Yuan, Xue III-304, III-483 Yuchuan, Yang IV-563 Yue, E. I-476 Zang, Yu III-257 Zang, Zhiyuan I-594 Zejian, Lei I-608 Zeng, Fanjiang I-321 Zeng, Qingtian I-203 Zeng, Yanwei II-381, II-392 Zeng, Yi III-241 Zeng, Zhixuan II-525 Zha, Xiaojing IV-382, IV-521 Zhang, Baihua III-525 Zhang, Baohui IV-134 Zhang, Baojun II-441 Zhang, Benhua I-428 Zhang, Changli IV-616 Zhang, Chengming III-390, III-403, III-452 Zhang, Chi I-103 Zhang, Chunlei II-441 Zhang, Chunmei III-29 Zhang, Chunqing III-620 Zhang, Dalei III-403 Zhang, Dongxing III-604 Zhang, Fan II-365 Zhang, Feng III-413 Zhang, Guoliang I-594 Zhang, Haihong I-721, II-118 Zhang, Hailiang II-1 Zhang, Hao I-437, II-357 Zhang, Haokun I-502 Zhang, Hong I-96, I-464, I-539 Zhang, Hongbin I-250, II-658, IV-134 Zhang, Jian I-623, III-341, III-656, IV-474, IV-537 Zhang, Jianhang I-343 Zhang, Jianhua III-304, III-483 Zhang, Jing I-381, I-698 Zhang, Jingjing I-623, III-656 Zhang, Jinheng II-706, IV-592 Zhang, Jishuai II-650 Zhang, Juan II-357
773
Zhang, Jun IV-246 Zhang, Junfeng I-56, II-615, III-638, III-672 Zhang, Junxiong II-102 Zhang, Kai II-23 Zhang, Lei IV-96 Zhang, Li II-357 Zhang, Liang II-716 Zhang, Lihua III-554 Zhang, Limin I-417 Zhang, Lingxian IV-672, IV-680 Zhang, Lingzi IV-691 Zhang, Longlong III-269 Zhang, Mei III-186 Zhang, Min I-569, II-198 Zhang, Mingfei IV-629 Zhang, Na I-367 Zhang, Ping IV-206 Zhang, Qing I-343 Zhang, Qingfeng II-158, II-531 Zhang, Rentian III-554 Zhang, Runqing II-339 Zhang, Shujuan I-721, II-118 Zhang, Shuyuan I-519 Zhang, Tingting II-400, II-579 Zhang, Tongda II-597 Zhang, Wei II-615 Zhang, Xiandi I-76, III-46, III-682, III-696 Zhang, Xiaodong II-53, II-691 Zhang, Xiaojing II-491 Zhang, Xiaolan IV-480, IV-537 Zhang, Xiaoyan III-146 Zhang, Xin III-66, III-75, IV-435, IV-701, IV-710 Zhang, Xu I-304 Zhang, Xuelan I-68 Zhang, Yang III-316, III-375 Zhang, Yanrong II-139 Zhang, Yaoli II-641 Zhang, Yu IV-221 Zhang, Yue I-227 Zhang, Yunhe III-66 Zhang, Yuou I-446 Zhang, Yuxiang II-597 Zhang, Zhen I-359 Zhao, Chunjiang I-76, III-580 Zhao, Dongjie III-289 Zhao, Dongmei III-473 Zhao, Fukuan I-125
774
Author Index
Zhao, Hu II-166 Zhao, Huamin I-721 Zhao, Huizhong I-569, II-198 Zhao, Jianshe III-598 Zhao, JiChun II-615 Zhao, Jingyin I-374, II-434, II-587 Zhao, Jingying III-222 Zhao, Lanying IV-294 Zhao, Liu I-290, II-83, II-234 Zhao, Longzhi IV-474, IV-480, IV-514, IV-537 Zhao, Mingjuan IV-480, IV-537 Zhao, Peng I-614 Zhao, Suolao II-441 Zhao, Ting II-252 Zhao, Wei I-155 Zhao, Wen IV-333 Zhao, Wenlong I-390 Zhao, Wenping I-16 Zhao, Xiaoming I-669 Zhao, Yanqing IV-398 Zhao, Yanru I-721 Zhao, Yujun II-561 Zhao, Yuling II-517 Zhao, Zhiyong II-177 Zheng, Guang I-437 Zheng, Huaiguo I-56 Zheng, Huoguo III-158, III-179, III-648 Zheng, Lihua III-473 Zheng, Meizhu IV-514 Zheng, Wengang III-66, III-75, IV-435 Zheng, Wenxiu III-379 Zheng, Yanxia I-519, II-177, II-473 Zheng, Youfei I-381 Zheng, Yuelan II-607 Zheng, Yujun I-125 Zheng, Zhihong II-23 Zhong, Guangrong III-231 Zhong, Mingdong IV-167 Zhong, Shiquan I-275, I-711, IV-575 Zhong, Zhiyou I-569, II-198 Zhou, Chao III-613, IV-368 Zhou, Dongsheng III-298 Zhou, Ermin II-139 Zhou, Fengqi IV-89
Zhou, Guo-Min I-62, II-300, II-623, III-113, III-138 Zhou, Huamao III-613 Zhou, Huilan IV-555 Zhou, Ji-Hui IV-443, IV-450 Zhou, Lianqing II-71 Zhou, Liying III-672 Zhou, Mingyao I-359 Zhou, Nan III-473 Zhou, Wei IV-246 Zhou, Weihong III-357 Zhou, XinJian IV-486 Zhou, Zexiang I-68 Zhou, Zhisheng II-309 Zhou, Zhu I-600, IV-246 Zhu, Chuanbao II-441 Zhu, Dawei II-441 Zhu, Dazhou I-563, III-84, III-92 Zhu, Dongnan I-526 Zhu, Fengmei IV-355 Zhu, Haiyan III-14 Zhu, Huaji III-661, IV-583 Zhu, Jianhua III-146 Zhu, Jie IV-410 Zhu, Juanuan II-441 Zhu, Qixin IV-279 Zhu, Shiping II-633 Zhu, Wei IV-486 Zhu, Wenquan I-681 Zhu, Yan I-446, II-479, III-186 Zhu, YePing II-110 Zhu, Yeping I-219, I-261, I-476 Zhu, Youyong I-227, I-335 Zhu, Yuwei II-400, II-579 Zhu, Zhenlin II-691 Zhu, Zhongkui IV-206 Zhu, Zhongxiang III-257 Zhuang, Weidong II-345, II-567 Zong, Li I-656, I-698 Zong, Wangyuan I-96, I-464 Zou, Qiang IV-124 Zude, Manuela III-84 Zuo, Changqing II-538 Zuo, Tingting II-131 Zuo, Yanjun I-1, I-532