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Model-based bridge recognition in high resolution SAR image

Model-based bridge recognition in high resolution SAR image

MIPPR 2009 - Automatic Target Recognition and Image Analysis: 6th International Symposium on Multispectral Image Processing and Pattern Recognition

作者： Pei, Deli Sun, Fuchun Wang, Hongqiao Chen, Ning Department of Computer Science and Technology Tsinghua University Beijing 100084 China State Key Lab. of Intelligent Technology and Systems Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing 100084 China Xi'an High Tech. Research Institute Xi'an Shanxi 710025 China

ISBN: (纸本)9780819478061

A new bridge recognition method in Synthetic Aperture Radar (SAR) image using bridge model and SVM is presented in this paper. Firstly, water region is extracted from original SAR image by self-adapt segmentation and mathematic morphological method. Then based on bridge model, the bridge candidates in water region can be found out and their texture feature can also be ***, with the usage of SVM, whether these objects are bridges or not can be identified and the real bridges can be mark ed in the SAR image, as well as the corresponding information such as position. Experiment results show that, with the help of water region segmentation and bridge model, the efficiency of the algorithm is greatly promoted, meanwhile, the recognition accuracy is guaranteed by high quality classifier of SVM. © 2009 Copyright SPIE - The International Society for Optical Engineering.

关键词： Synthetic aperture radar

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Multi-step Prediction Error Approach for MPC Performance Monitoring *

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IFAC Proceedings Volumes 2009年第11期42卷 482-487页

作者： Yu Zhao Jian Chu Hongye Su Biao Huang State Key Lab. of Industrial Control Technology Institute of Cyber Systems and Control Zhejiang University Hangzhou China Department of Chemical and Materials Engineering University of Alberta Edmonton AB Canada T6G 2G6

Abstract Performance monitoring of model predictive control systems (MPC) has received a great interest from both academia and industry. In recent years some novel approaches for multivariate control performance monitoring have been developed without the requirement of process models or interactor matrices. Among them the prediction error approach has been shown to be a promising one, but it is k-step prediction based and may not be fully comparable with the MPC objective that is multi-step prediction based. This paper develops a multi-step prediction error approach for performance monitoring of model predictive control systems, and demonstrates its application in an industrial MPC performance monitoring and diagnosis problem.

关键词： Multivariable control systems Model predictive control Performance evaluation Performance monitoring Prediction error methods

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Immersion and Invariance Adaptive control of Nonlinearly Parameterized Nonlinear systems

Immersion and Invariance Adaptive Control of Nonlinearly Par...

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2009 American control Conference (ACC 2009)

作者： Xiangbin Liu Romeo Ortega Hongye Su Jian Chu State Key Lab. of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University Hangzhou 310027 P. R. China Laboratoire des Signaux et Systemes Supelec 9112 Gif-sur-Yvette France

ISBN: (纸本)9781424445233

A new framework to design adaptive controllers for nonlinearly parameterized systems is proposed in this paper. The key step is the construction of a monotone function, which explicitly depends on some of the estimator tuning parameters. Monotonicity--or the related property of convexity--have already been explored by several authors with convexity being an a priori assumption that is valid only on some region of state space. In our approach monotonicity is enforced by the designer, effectively becoming a synthesis tool. One consequence of this fact is that the controller does not rely on state-dependent switching. In order to dispose of degrees of freedom to render the function monotone we depart from standard adaptive control and adopt instead the recently introduced Immersion and Invariance approach.

关键词： Adaptive control Nonlinear systems Programmable control control systems Nonlinear control systems Parameter estimation state-space methods Robust stability Switches Standards development

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Research on reconfigurable digital signal processor based on control dataflow graph

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Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology 2009年第SUPPL. 1期41卷 16-21页

作者： Duan, Ran Liang, Jie Wang, Yan-Ning State Key Lab. of National Defense for Aerospace Intelligent Control Beijing 100854 China Beijing Aerospace Automatic Control Institute Beijing 100854 China

The better computing structure matches with the application algorithm, the higher performance and efficiency can be got. Reconfigurable computing has the flexibility of software and the efficiency of ASIC. The combination of DSP processors and reconfigurable computing technology can improve the single DSP processor performance to higher level. The paper proposes a reconfigurable DSP processor model based on the characteristics of control data flow of DSP algorithms and the adaptability of reconfigurable architectures. The address generation units and data-path can be reconfigured according to the address and data calculation streams of the Data Flow Graph, making the processor more adaptable. Using several DSP kernel algorithms, the processor performance is evaluated. The simulation results indicate that reconfiguration can efficiently improve DSP processing performance.

关键词： Digital signal processors

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Lightning protection study of transmission line, Part I: Lightning parameters

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Gaodianya Jishu/High Voltage Engineering 2009年第12期35卷 2903-2909页

作者： Chen, Shui-Ming He, Jin-Liang Zeng, Rong State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

Obtaining actual lightning parameters is the fundament of lightning protection of transmission lines. Based on the comprehensive analysis on the methods to acquire lightning parameters, we analyzed the current research states and existed problems of lightning parameters, including annual lightning day, ground flash density, magnitude and waveform of lightning current. The lightning activities have obvious topographical feature, presently the lightning location system (LLS) should be fully applied to acquire the annual lightning day, ground flash density, magnitude of lightning current in different areas. Moreover, the monitoring devices of lightning current should be installed on typical transmission towers with different voltage grades in different areas to obtain the characteristics of real lightning current waveforms and magnitudes, and calibrate and check the lightning current magnitudes obtained from LLS. All these would make the lightning protection of power system focusing on the actual targets. Four sets of the developed monitoring devices of lightning current were installed, and the first lightning current waveform in China, which was similar to the standard waveform recommended by CIGRE, was recorded.

关键词： Electric lines

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Lightning protection study of transmission line, Part II: Analysis methods

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Gaodianya Jishu/High Voltage Engineering 2009年第12期35卷 2910-2916页

作者： Zeng, Rong He, Jin-Liang Chen, Shui-Ming State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

Design is the key of lightning protection of transmission lines, and lightning protection analysis is the base to estimate the lightning protection behaviors of transmission line and the effect of lightning protection measures for transmission line. We mainly discussed the development states and the existed problems in lightning protection analysis of transmission line in the world, presented the analysis methods on the lightning backflash and shielding failure of transmission line and their comprehensive applications, and proposed the suitable models and methods for lightning protection analysis of transmission line. The whole-wave- progress analysis model should be applied to calculate the lightning transient characteristics of transmission line when the lightning strikes the tower or the overhead ground wires of transmission line;different analysis methods, such as electrogeometric method, the leader propagating model and the fractal model, should be used to calculate the shielding failure behaviors of transmission line. The lightning protection analysis of transmission lines should consider the micro-typological characteristics and the area difference of lightning parameters along transmission line, and comprehensively estimate the lightning protection behaviors of transmission line sections.

关键词： Electric lines

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Lightning protection study of transmission line, Part III: Protection measures

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Gaodianya Jishu/High Voltage Engineering 2009年第12期35卷 2917-2923页

作者： He, Jin-Liang Zeng, Rong Chen, Shui-Ming State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

The lightning accidents threaten the safe operation of power system. We comprehensively analyzed the developing states, the existed problems in analysis methods and measures of transmission line lightning protection, and discussed the key issues of transmission line lightning protection in China that should be studied. The lightning protection measures are divided into back-up type and leading-type methods, so-called back-up type method is used in lightning protection of transmission line in China, which complicates lightning protection;but the so-called leading-type method is used in other countries, which simplifies lightning protection. The lightning protection measures for different sections of transmission lines should be comprehensively estimated and proposed by considering the micro-topographical feature and the regional performances of lightning parameters along transmission line. The lightning protection should be fully considered in transmission line design, reducing shielding angle of overhead wire, decreasing grounding resistances of tower footings, and suitably installing line surge arresters are fundamental methods of lightning protection of new transmission line.

关键词： Electric lines

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Transient stability assessment based on 2D combined attribute decision tree

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2009年第SUPPL. 1期29卷 17-24页

作者： Wang, Kang Sun, Hong-Bin Zhang, Bo-Ming Wu, Wen-Chuan Jiang, Wei-Yong State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

A method for the power system transient stability assessment based on 2D combined attribute decision tree was proposed. Different from single attribute decision trees, the 2D trees combine two attributes as one automatically to improve its classifying ability in case of multi-dimension and nonlinear border among classes. In the proposed 2D tree, Gini coefficient based 2D combined splitting criterions was adopted and search method for splitting line in an inverse direction was developed. Case study was carried out in one-machine infinite bus system, IEEE 39-bus system and a real provincial system. Results show that, 2D combined attribute decision trees generated by the proposed method are smaller in structure, have the higher accuracy and generalization ability than that generated by the single attribute decision trees. Meanwhile, some important relationship between physical variables in power systems can be mined by the proposed method. Advantages mentioned above make that the proposed method is potential for real-life power system applications. © 2009 Chin. Soc. for Elec. Eng.

关键词： Decision trees

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An automatic online news Topic keyphrase extraction system

An automatic online news Topic keyphrase extraction system

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2008 IEEE/WIC/ACM International Conference on Web Intelligence, WI 2008

作者： Wang, Canhui Zhang, Min Ru, Liyun Ma, Shaoping State Key Lab. of Intelligent Technology and Systems CS and T Department Tsinghua University Beijing 100084 China

ISBN: (纸本)9780769534961

News Topics are related to a set of keywords or keyphrases1. Topic keyphrases briefly describe the key content of topics and help users decide whether to do further reading about them. Moreover, keyphrases of a news topic can be considered as a cluster of related terms, which provides term relationship information that can be integrated into information retrieval models. In this paper, an automatic online news topic keyphrase extraction system is proposed. News stories are organized into topics. keyword candidates are firstly extracted from single news stories and filtered with topic information. Then a phrase identification process combines keywords into phrases using position information. Finally, the phrases are ranked and top ones are selected as topic keyphrases. Experiments performed on practical Web datasets show that the proposed system works effectively, with a performance of precision=70.61% andrecall=67.94%. © 2008 IEEE.

关键词： Extraction

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Dynamic features measurement and analysis for large-scale networks

Dynamic features measurement and analysis for large-scale ne...

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ICC 2008 - 2008 IEEE International Conference on Communications Workshops

作者： Qin, Tao Guan, Xiaohong Li, Wei Wang, Pinghui IEEE MOE Key Lab. for Intelligent Networks and Network Security State Key Lab. for Manufacturing Systems Xi'an Jiaotong University Xi'an China Department of Automation TNLIST Lab. Tsinghua University Beijing China

ISBN: (纸本)9781424420513

Detecting and measuring the changes of temporal traffic patterns in large scale networks are crucial for effective network management. This paper presents the concept of region flow to aggregate traffic packets. Regions are defined by the IP prefix, and a region flow is a group of packets with the same source and destination region during a time interval. In this way, the number of flows can be reduced significantly and a better extraction of pivotal traffic metrics is generated. Three traffic features: source connection degree, destination connection degree and packet distribution ratio are proposed to capture the dynamic change of the flow patterns between regions and the Renyi cross entropy are applied to measure and detect the changes. The experimental results show that the method proposed in this paper can capture the dynamic traffic features effectively for 10Gbps backbone networks, and can be used for detecting abnormal network behaviors. ©2008 IEEE.

关键词： Feature extraction

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