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International Conference on Neural Information Processing

作者： J. Bakus M.F. Hussin M. Kamel Department of Systems Design Engineering University of Waterloo Waterloo ONT Canada Department of Computer Science & Automatic Control Alexandria University Alexandria Egypt

ISBN: (纸本)9810475241

Most of the existing techniques for document clustering rely on a "bag of words" document representation. Each word in the document is considered as a separate feature, ignoring the word order. We investigate the use of phrases rather than words as document features for the document clustering. We present a phrase grammar extraction technique, and use the extracted phrases as the features in a self-organizing map based document clustering algorithm. We present clustering results using the REUTERS corpus and show an improvement in clustering performance using both entropy and F-measure evaluation measures.

关键词： Data mining Clustering algorithms Machine learning Merging computer science automatic control Entropy Internet Information retrieval Organizing

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Improving quality-of-control using flexible timing constraints: metric and scheduling

Improving quality-of-control using flexible timing constrain...

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Real-Time Systems Symposium (RTSS)

作者： P. Marti J.M. Fuertes G. Fohler K. Ramamritham Automatic Control Department Universitat Poliltècnica de Catalunya Barcelona Spain Department of Computer Engineering Mälardalen University Vasteras Sweden Computer Science and Engineering Department IIT Mumbai India

Closed-loop control systems are dynamic systems subject to perturbations. One of the main concerns of the control is to design controllers to correct or limit the deviation that transient perturbations cause in the controlled system response. The smaller and shorter the deviation, the better the achieved performance. However, such controllers have been traditionally implemented using fixed timing constraints (periods and deadlines). This precludes controllers to execute dynamically, accordingly to the system dynamics, which may lead to sub-optimal implementations: although higher execution rates may be preferable when reacting to perturbations in order to minimize the response deviations, they imply wastage of resources when the system is in equilibrium. In this paper we argue and demonstrate that the responsibility of maximizing the performance of closed-loop systems relies on both the controller designer and the scheduler. We show that the dynamic optimization of the quality of the controlled system response calls for (a) flexible control task timing constraints that deliver effective control performance; flexible constraints allow us to achieve faster reaction by adaptively choosing the controller sampling rate and completion time upon transient perturbations, (b) a quality-of-control (QoC) metric; it associates with each control task timing a quantitative value expressing control performance (in terms of the closed-loop system error), and (c) new scheduling approaches; their goal is to quickly react to perturbations by dynamically scheduling tasks based on the chosen control task execution parameters to maximize the QoC. This combination offers the possibility of taking scheduling decisions based on the control information for each control task invocation, rather than using fixed timing constraints with constant periods and deadlines.

关键词： Timing control systems Sampling methods Dynamic scheduling automatic control Constraint theory Delay effects Processor scheduling control theory Real time systems

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ROBUST CONGESTION control IN HIGH SPEED COMMUNICATION NETWORKS: A MODEL PREDICTIVE control APPROACH

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IFAC Proceedings Volumes 2002年第1期35卷 103-108页

作者： Hua O. Wang Yongru Gu Huajing Fang Laboratory for Intelligent and Nonlinear Control (LINC) Department of Electrical and Computer Engineering Duke University Durham NC 27708-0291 USA Center for Nonlinear and Complex Systems Department of Control Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

In this paper, the design of explicit rate-based congestion control in high speed communication networks is considered. At a bottleneck node, there are multiple best-effort sources competing with other high priority cross traffic sources. The goal of congestion control is to achieve high link utilization, low packet loss, low delay, and fairness among the best-effort sources. In this paper, the high priority traffic is described by an autoregressive integrated moving average (ARIMA) process. To deal with the propagation delays associated with the best-effort sources, model predictive control, particularly, generalized predictive control, techniques are proposed to solve the congestion problem here. It is demonstrated that the proposed controller performs well and is robust to delay uncertainties. In addition, in a multiple-nodes configuration, the controller provides max-min fairness.

关键词： Communication control applications Model-based control Predictive control Communication networks Time delay Robustness

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Enhancement of the DNA microarray chip images

Enhancement of the DNA microarray chip images

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International Conference on Digital Signal Processing (DSP)

作者： M.K. Szczepanski B. Smolka K.N. Plataniotis A.N. Venetsanopoulos Department of Automatic Control Silesian University of Technology Gliwice Poland Edward S. Rogers Sr. Department of Electrical and Computer Engineering University of Toronto Toronto Canada

In this paper a novel method of noise reduction in color images is presented. The new technique is capable of attenuating both impulsive and Gaussian noise, while preserving and even enhancing the sharpness of the image edges. Extensive simulations reveal that the new method outperforms significantly the standard techniques widely used in multivariate signal processing. In this work we apply the new noise reduction method for the enhancement of the images of gene chips. We demonstrate that the new technique is capable of reducing various kinds of noise present in microarray images and that it enables efficient spot location and estimation of the gene expression level, due to the smoothing effect and preservation of the spot edges. This paper contains the comparison of the new technique of noise reduction with the standard procedures used for the processing of vector valued images, as well as examples of the efficiency of the new algorithm when applied to typical microarray images.

关键词： DNA Probes Fluorescence Noise reduction Gene expression Sequences Surface emitting lasers Strontium Educational institutions Color

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New technique for the restoration of noisy color images

New technique for the restoration of noisy color images

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International Conference on Digital Signal Processing (DSP)

作者： B. Smolka M.K. Szczepanski K.N. Plataniotis A.N. Venetsanopoulos Department of Automatic Control Silesian University of Technology Gliwice Poland Edward S. Rogers Sr. Department of Electrical and Computer Engineering University of Toronto Toronto Canada

In this paper we propose a new efficient algorithm of noise suppression in color images. The new technique of multichannel image enhancement is capable of reducing impulsive and Gaussian noise and it outperforms the standard methods of noise reduction. In this paper a new smoothing operator, based on a random walk model and on a fuzzy similarity membership function of pixels connected by digital paths is introduced. The efficiency of the proposed method has been tested on the standard color images using the widely used objective image quality measures.

关键词： Image restoration Colored noise Color Image enhancement Gaussian noise Noise reduction Smoothing methods Testing Measurement standards Image quality

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Mobility analysis of planar mobile robots

Mobility analysis of planar mobile robots

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Wheekuk Kim Seung-Eun Lee Byung-Ju Yi Department of Control and Instrumentation Engineering Korea University South Korea School of Electrical Engineering and Computer Science Hanyang University South Korea

In this paper, the mobility analysis of various planar mobile robots are performed. Two different approaches are employed for that purpose. In the first approach, joint screws are used to find the size of a feasible joint motion space for each of independent loops of mobile mechanisms. Particularly, the concept of "representative screws" is introduced to represent the feasible motion spaces for subsets of joints belonging to either a loop or a sub-system consisting of several closed loops. In the second approach, imaginary joints are employed to compensate for the lack of geometric generality of mobile robots. It is confirmed that both approaches are useful in the mobility analysis for various type of planar mobile robots even in the case of lacking geometric generality.

关键词： Mobile robots Wheels Fasteners Performance analysis Image analysis Motion analysis Instruments computer science Orbital robotics Friction

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An algebraic approach to iterative learning control

An algebraic approach to iterative learning control

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IEEE International Symposium on Intelligent control (ISIC)

作者： J. Hatonen K.L. Moore D.H. Owens Automatic Control and Systems Engineering Department University of Sheffield Sheffield UK Systems Engineering Laboratory University of Oulu Linnanmaa Finland Department of Electrical and Computer Engineering College of Engineering Utah State University Logan UT USA

In this paper discrete-time iterative learning control (ILC) systems are analysed from an algebraic point of view. The algebraic analysis shows that an ILC synthesis problem can be considered as a tracking problem of a multi-channel step-function. Furthermore, the plant to be controlled is a static multivariable plant. Another major contribution of this paper is a general convergence theory of ILC systems in terms of their closed-loop poles. This convergence theory shows that time-variant ILC control laws should be typically used instead of time-invariant control laws in order to guarantee good transient tracking behaviour. Simulations high-light the different theoretical findings in this paper.

关键词： Iterative methods automatic control control systems Convergence Systems engineering and theory Intelligent systems Educational institutions Laboratories control system synthesis Modeling

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Robust exponential stabilization for a class of nonlinear dynamical systems with unmatched uncertainties

Robust exponential stabilization for a class of nonlinear dy...

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IEEE Conference on control Technology and Applications (CCTA)

作者： Kai Yu Chang-An Zhao Guang-Ren Duan Department of Control Science and Engineering Harbin Institute of Technology Harbin People's Republic of China Department Electrical and Computer Engineering Northeastern University USA

In this paper, the problem of robust exponential stabilization for a class of nonlinear dynamical systems with unmatched uncertainties is investigated. Based on the stability of the nominal system, a new approach to synthesizing a class of continuous state feedback controllers for uncertain nonlinear dynamical systems is proposed. By such a class of feedback controller, we can guarantee exponential stability of uncertain nonlinear dynamical systems. Our approach gives a clear insight into system analysis. Finally, an illustrative example is given to demonstrate the utilization of the approach developed.

关键词： Robustness Nonlinear dynamical systems Uncertainty Stability control system synthesis State feedback control systems Nonlinear control systems Adaptive control Mathematical model

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A Virtual Laboratory for Macro Universities Using Mobile Agent Techniques

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International Journal of computer Processing of Languages 2002年第1期15卷 1-18页

作者： C. R. DOW C. C. SHEN J. H. LIN S. C. CHEN C. Y. LIN Department of Information Engineering and Computer Science Feng Chia University Taichung Taiwan R. O. C. Department of Automatic Control Engineering Feng Chia University Taichung Taiwan R. O. C.

This work designs, develops and implements a virtual laboratory for digital circuit design in Macro Universities that can create a rich learning environment for students from all over the world. Our system consists of four parts: agent execution environments, mobile agents, wrapper agents and experimental platforms. Mobile agents are received and executed in the agent execution environment, which provides locations and other resources for the mobile agents. The wrapper agent acts as a middleware for the mobile agent and the experimental platform. The experimental platform is an existing application program that could be a learning program, such as a CAI tool or a design tool, such as a CAD system. The major merit of our system is that it enables network capability for a standalone program without the need for the source code of the original program. The prototype of our virtual laboratory is targeted at a digital circuit laboratory. Experimental results demonstrate the feasibility of our approach.

关键词： Virtual Laboratory Macro University Mobile Agent Aglet Wrapper

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Model reference parametric adaptive iterative learning control 15th

Model reference parametric adaptive iterative learning contr...

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15th World Congress of the International Federation of automatic control, 2002

作者： Yu, H. Deng, M. Yang, T.C. Owens, D.H. School of Engineering and Computer Science Exeter University ExeterEX4 4QF United Kingdom School of Engineering and Information Technology Sussex University BrightonBN1 9QT United Kingdom Department of Automatic Control and Systems Sheffield University SheffieldS1 3JD United Kingdom

ISBN: (纸本)9783902661746

Most of iterative learning control (ILC) methods requires that the relative degree of the plant is less than 2 for a linear system or the plant is passive for a non-linear system. A new model reference parametric adaptive iterative learning control using the command generator tracker (CGT) theory is proposed in this paper. The method can be applied to control a plant with a higher relative degree and it only requires to iteratively adjust nm + 2 parameters for an SISO plant. Therefore, the ILC control system is very simple. The proposed method is in the spirit of simple adaptive control which has received intensive researches during past two decades. Simulation results show the effectiveness and usefulness of the proposed method. Copyright © 2002 IFAC.

关键词： Model reference adaptive control

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