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IEEE International Conference on Systems, Man and Cybernetics

作者： Huijun Gao Yan Zhao Tongwen Chen Space Control and Inertial Technology Research Center Harbin Institute of Technology Harbin China Department of Electrical and Computer Engineering University of Alberta Edmonton Canada

This paper investigates the problem of H infin fuzzy control of nonlinear systems under unreliable communication links. The nonlinear plant is represented by a Takagi-Sugeno fuzzy model, and the control strategy takes the form of parallel distributed compensation. The communication links, existing between the plant and controller, are assumed to be imperfect (that is, data-packet dropouts occur intermittently, which appear typically in a network environment), and stochastic variables satisfying the Bernoulli random binary distribution are utilized to model the unreliable communication links. Attention is focused on the design of H infin controllers such that the closed- loop system is stochastically stable and preserves a guaranteed H infin , performance. Two approaches are developed to solve this problem, based on quadratic Lyapunov function and basis- dependent Lyapunov function respectively. Several examples are provided to illustrate the usefulness and applicability of the developed theoretical results.

关键词： Communication system control Fuzzy systems Fuzzy control control systems Lyapunov method Stability analysis Nonlinear systems control system synthesis Space technology Stochastic processes

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Hybrid WT Based-DCT Based Face Recognition

Hybrid WT Based-DCT Based Face Recognition

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IEEE International Conference on Signal Processing and Communications, ICSPC

作者： P. Abouzar S. Yousefi S. K. Setarehdan Graduate student of Digital communications Chalmers University of Technology Sweden Graduate Student in Electrical Engineering Oregon State University Corvallis OR USA Control and intelligent processing center of Excellence Faculty of Electrical and computer Engineering University of Tehran Iran

In this paper a robust face recognition algorithm based on both WT (wavelet transform) and DCT (discrete cosine transform) is presented. The proposed algorithm takes the advantage of data reduction property of both WT and DCT, hence a large reduction in the data size, while saving most of the information. Initially, 2D WT is used to compress the data at various levels, which also removes the high frequency noise from the input image. Then 1D DCT is applied to each column of the resulting image from the previous step for more data reduction. Finally, PCA (principle component analysis) is applied to extract principle components of the data in the training set. SVM (support vector machine) is then used to separate different classes (picture of different persons obtained at various conditions). Comparison of the proposed algorithm with previously reported WT based algorithm shows a significant improvement in the classification results.

关键词： Face recognition Discrete cosine transforms Discrete wavelet transforms Support vector machines Support vector machine classification Robustness Image coding Frequency Noise level Principal component analysis

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Subtleties in Robust Stability of Discrete-time Piecewise Affine Systems

Subtleties in Robust Stability of Discrete-time Piecewise Af...

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American control Conference (ACC)

作者： M. Lazar W.P.M.H. Heemels A.R. Teel University of California Santa Barbara Santa Barbara CA US Department of Mechanical Engineering Eindhovan University of Technology Eindhoven Netherlands Center for Control Engineering and Computation Department of Electrical and Computer Engineering University of California Santa Barbara USA

In this paper we consider (inherent) robustness of discrete-time piecewise affine (PWA) systems. We demonstrate, via examples, that globally exponentially stable discrete-time PWA systems may have no robustness. More precisely, we show that the exponential stability property cannot prevent that arbitrarily small additive disturbances keep the state trajectory far from the origin. Mathematically speaking, this means that the system is not input-to-state stable with respect to arbitrarily small disturbances. The non-robustness property is related to the absence of a continuous Lyapunov function. These results indicate that one should be careful with existing stability analysis and synthesis methods for PWA systems that rely on discontinuous Lyapunov functions, as no robustness might be present. However, as the search for Lyapunov functions for discrete-time PWA systems often employs discontinuous Lyapunov functions (e.g. piecewise quadratic ones), robustness tests based on discontinuous Lyapunov functions are needed. Such tests are proposed in this article.

关键词： Robust stability Lyapunov method Robustness Asymptotic stability control system synthesis control systems Additives Stability analysis System testing Biological system modeling

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Complex Hybrid Systems: Stability Analysis for Omega Limit Sets

Complex Hybrid Systems: Stability Analysis for Omega Limit S...

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第二十六届中国控制会议

作者： Goebel Rafal Sanfelice Ricardo G. Teel Andrew R. 3518 NE 42 St. SeattleWA 98105USA Center for Control Dynamical Systemsand ComputationDepartment of Electrical and Computer Engineering University of California

This paper focuses on the asymptotic stability properties of omega limit sets for complex hybrid dynamical systems,which are commonly found in systems and *** spells out specific stability results that follow when a hybrid dynamical system has certain structure,e.g.,when it admits a decomposition resembling a cascade of hybrid dynamical systems.

关键词： Hybrid systems Asymptotic stability Omega limit sets

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Filtering of discrete linear repetitive processes with ∞ and 2-∞ performance

Filtering of discrete linear repetitive processes with ∞ an...

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2007 IEEE International Symposium on Circuits and Systems, ISCAS 2007

作者： Ligang, Wu Lam, James Paszke, Wojciech Galkowski, Krzysztof Rogers, Eric Kummert, Anton Space Control and Inertial Technology Research Center Harbin Institute of Technology Harbin 150001 China Department of Mechanical Engineering University of Hong Kong Pokfulam Road Hong Kong Hong Kong Institute of Control and Computation Engineering University of Zielona Góra 65-246 Zielona Góra Poland School of Electronics and Computer Science University of Southampton Southampton SO17 IBJ United Kingdom University of Wuppertal Faculty of Electrical Information and Media Engineering Communication Theory

This paper considers the general filtering problem for a distinct class of two-dimensional (2-D) discrete linear systems, i.e. information propagation in two independent directions, known as discrete linear repetitive processes which are of both system-theoretic and applications interest. In particular, new results on the design of filters with guaranteed levels of performance are developed. These take the form of algorithms for the design of an ∞ and 2-∞ dynamic output feedback filter which guarantees that the resulting filtering error process is stable and has prescribed disturbance attenuation performance as measured by ∞ and 2- ∞ norms. © 2007 IEEE.

关键词： Signal filtering and prediction

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Relaxed characterizations of smooth patchy control Lyapunov functions

Relaxed characterizations of smooth patchy control Lyapunov ...

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作者： Goebel, Rafal Prieur, Christophe Teel, Andrew R. Department of Mathematics University of Washington Seattle WA 98195-4350 United States LAAS-CNRS 7 Avenue du Colonel Roche 31077 Toulouse Cedex 4 France Center for Control Dynamical Systems and Computation Department of Electrical and Computer Engineering University of California Santa Barbara CA 93106-9560 United States

ISBN: (纸本)9783902661289

A smooth patchy control Lyapunov function for a nonlinear control system consists of an ordered family of smooth local control Lyapunov functions, whose open domains form a locally finite cover of the state space of the system, and which satisfy a certain arrangement property. In contrast to (Goebel et al., IEEE CDC, 2006), on each intersection of the domains, we do not impose a decrease condition of the local control Lyapunov functions when the index increases. We show a construction, based on such a patchy control Lyapunov function, of a stabilizing hybrid feedback that is robust to measurement noise. Copyright © 2007 IFAC.

关键词： Hybrid systems

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Cooperative Graph-Based Model Predictive Search

Cooperative Graph-Based Model Predictive Search

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Proceedings of the 46th IEEE Conference on Decision and control, Pages 5971-6447

作者： James R. Riehl Gaemus E. Collins Joao P. Hespanha Center for Control Dynamical Systems and Computation Electrical and Computer Engineering Department University of California Santa Barbara CA USA Toyon Research Corporation Goleta CA USA

ISBN: (纸本)9781424414970;1424414970

We present a receding-horizon cooperative search algorithm that jointly optimizes routes and sensor orientations for a team of autonomous agents searching for a mobile target. By sampling the region of interest at locations with high target probability, we reduce the continuous search problem to an optimization on a finite graph. Paths are computed on this graph using a receding horizon approach, in which the horizon is a fixed number of waypoints. To facilitate a fair comparison between paths of varying length on a non-uniform graph, we use an optimization criterion corresponding to the probability of finding the target per unit time. Using this algorithm, we show that the team discovers the target in finite time with probability one. Simulations verify that this algorithm makes effective use of agents and performs significantly better than previously proposed search algorithms. We have also successfully tested this search algorithm on a physical system consisting of two UAVs with gimbal-mounted cameras.

关键词： SEARCHING ALGORITHM optimal criterion maneuvering target Horizon Intelligent agents Probability Line graph Targets algorithms region of interest Teams Paths continuous search Byways

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Robust fault detection for discrete-time Markovian jump systems with mode-dependent time-delays

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控制理论与应用（英文版） 2007年第2期5卷 139-144页

作者： Hongru WANG Changhong WANG Shaqshuai MOU Huijun GAO School of Information ＆ Communication Engineering Harbin Engineering University Harbin Heilongjiang 150001 China Space Control and Inertial Technology Research Center Harbin Institute of Technology Harbin Heilongjiang 150001 China Department of Electrical and Computer Engineering The University of Alberta Edmonton Alberta T6G 2V4 Canada

This paper investigates a fault detection problem for a class of discrete-time Markovian jump systems with norm-bounded uncertainties and mode-dependent time-delays. Attention is focused on constructing the residual generator based on the filter of which its parameters matrices are dependent on the system mode, that is, the fault detection filter is a Markovian jump system as well. The design of fault detection filter is reduced to H-infinity filtering problem by using H-infinity control theory, which can guarantee the difference between the residual and the fault （or, more generally weighted fault） as small as possible in the context of enhancing the robustness of residual to modeling errors, control inputs and unknown inputs. Sufficient condition for the existence of the above filters is established by means of linear matrix inequalities, which can be readily solved by using standard numerical software. A numerical example is given to illustrate the feasibility of the proposed method.

关键词： Markovian jump system Time-delay Fault detection H-infinity filtering Linear matrix inequality Residual

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AUTOMATIC BRAIN TUMOR SEGMENTATION USING TISSUE DIFFISIVITY CHARACTERISTICS

AUTOMATIC BRAIN TUMOR SEGMENTATION USING TISSUE DIFFISIVITY ...

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IEEE International Symposium on Biomedical Imaging

作者： Azadeh Yazdan-Shahmorad Hesamoddin Jahanian Suresh Patel Hamid Soltanian-Zadeh Radiology Department Henry Ford Health System Medical Image Analysis Laboratory Detroit MI USA Electrical and Computer Engineering Department Wayne State University Detroit MI USA Biomedical Engineering Department University of Michigan Ann Arbor MI USA Control and Intelligent Processing Center of Excellence Electrical and Computer Engineering Department Faculty of Engineering University of Tehran Tehran Iran

ISBN: (纸本)9781424406715;1424406714

Water diffusion measurements have been shown to be sensitive to tissue cellular size, extra cellular volume, and membrane permeability. Therefore, diffusion tensor imaging (DTI) by MRI can be used to characterize highly cellular regions of tumors versus acellular regions, distinguishing cystic regions from solid regions. An automatic segmentation method is proposed in this paper based on a multi-phase clustering algorithm to segment the brain tumors in a feature space extracted from DTI images. The algorithm is applied on images of a total of 20 patients with 4 different types of tumors. The tumor region segmentation was 92% accurate based on the segmentation results using anatomical images and 100% accurate based on biopsy results. In general, the segmentation results obtained by the proposed method revealed a strong agreement with the biopsy results and anatomical images, providing support for the accuracy and robustness of the proposed feature space and the segmentation procedure.

关键词： Neoplasms Image segmentation Diffusion tensor imaging Clustering algorithms Biopsy Permeability measurement Volume measurement Size measurement Biomembranes Magnetic resonance imaging

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UNITING LOCAL AND GLOBAL OUTPUT FEEDBACK controlLERS

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IFAC Proceedings Volumes 2007年第12期40卷 492-497页

作者： Christophe Prieur Andrew R. Teel LAAS–CNRS 7 Avenue du Colonel Roche 31077 Toulouse Cedex 4 France Center for Control Dynamical Systems & Computation Department of Electrical and Computer Engineering University of California Santa Barbara CA 93106-9560

We consider control systems for which we know two stabilizing output feedback controllers. One is globally asymptotically stabilizing, while the other one is only locally asymptotically stabilizing. We look for a composite output feedback control law that is equal to the local feedback on a neighborhood of the origin and that is globally asymptotically stabilizing. We insist on using only output feedback controllers to solve this uniting problem. Since we want some robustness with respect to measurement noise, actuator errors and external disturbances, we consider hybrid output feedback controllers, following recent developments in the literature on robustness in hybrid systems. Under an input-output-to-state stability assumption, we exhibit a solution of this uniting problem by means of a dynamic hybrid output feedback controller.

关键词： hybrid systems global stabilization local performance output feedback robustness

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