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FUZZY-BASED NETWORK BANDWIDTH DESIGN UNDER DEMAND UNCERTAINTY

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Journal of systems science & Complexity 2010年第1期23卷 61-70页

作者： Lean YU Wuyi YUE Shouyang WANG institute of systems science MADIS Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijiny 100190 China Department of Intelligence and Informatics Konan University Kobe 658-8501 Japan. institute of systems science MADIS Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China.

In communication networks （CNs）, the uncertainty is caused by the dynamic nature of the traffic demands. Therefore there is a need to incorporate the uncertainty into the network bandwidth capacity design. For this purpose, this paper developed a fuzzy methodology for network bandwidth design under demand uncertainty. This methodology is usually used for offiine traffic engineering optimization, which takes a centralized view of bandwidth design, resource utilization, and performance evaluation. In this proposed methodology, uncertain traffic demands are first handled into a fuzzy number via a fuzzification method. Then a fuzzy optimization model for the network bandwidth allocation problem is formulated with the consideration of the trade-off between resource utilization and network performance. Accordingly, the optimal network bandwidth capacity can be obtained by maximizing network revenue in CNs. Finally, an illustrative numerical example is presented for the purpose of verification.

关键词： Communication networks demand uncertainty fuzzy set theory network bandwidth design network optimization.

ROBUST CONSENSUS AND SOFT CONTROL OF MULTI-AGENT systems WITH NOISES

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Journal of systems science & Complexity 2008年第3期21卷 406-415页

作者： Lin WANG Lei GUO institute of systems science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

This paper considers the problem of robust consensus for a basic class of multi-agent systems with bounded disturbances and with directed information flow. A necessary and sufficient condition on the robust consensus is first presented, which is then applied to the analysis, control and decision making problems in the noise environments. In particular, the authors show how a soft control technique will synchronize a group of autonomous mobile agents without changing the existing local rule of interactions, and without assuming any kind of connectivity conditions on the system trajectories.

关键词： Directed graph robust consensus soft control time-varying systems

ON THE OBSERVABILITY AND DETECTABILITY OF LINEAR STOCHASTIC systems WITH MARKOV JUMPS AND MULTIPLICATIVE NOISE

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Journal of systems science & Complexity 2010年第1期23卷 102-115页

作者： Yuanhua NI Weihai ZHANG Haitao FANG Key Laboratory of systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China. College of Information and Electrical Engineering Shandong University of Science and Technology Qingdao China.

This paper presents the notions of exact observability and exact detectability for Markov jump linear stochastic systems of Ito type with multiplieative noise （for short, MJLSS）. Stochastic Popov-Belevith-Hautus （PBH） Criterions for exact observability and exact detectability are respectively obtained. As an application, stochastic H2/H∞ control for such MJLSS is discussed under exact detectability.

关键词： Exact detectability exact observability Markov jump systems multiplicative noise PBH Criterion stochastic H2/H∞ control.

FREQUENTIST MODEL AVERAGING ESTIMATION:A REVIEW

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Journal of systems science & Complexity 2009年第4期22卷 732-748页

作者： Haiying WANG Xinyu ZHANG Guohua ZOU academy of Mathematics and systems science,chinese academy of sciences,beijing 100190,china. academy of Mathematics and systems science Chinese Academy of Sciences Beijing 100190 China

In applications, the traditional estimation procedure generally begins with model *** a specific model is selected, subsequent estimation is conducted under the selected model withoutconsideration of the uncertainty from the selection process. This often leads to the underreportingof variability and too optimistic confidence sets. Model averaging estimation is an alternative to thisprocedure, which incorporates model uncertainty into the estimation process. In recent years, therehas been a rising interest in model averaging from the frequentist perspective, and some importantprogresses have been made. In this paper, the theory and methods on frequentist model averagingestimation are surveyed. Some future research topics are also discussed.

关键词： Adaptive regression asymptotic theory frequentist model averaging model selection,optimality.

IMPLICITIZATION USING UNIVARIATE RESULTANTS

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Journal of systems science & Complexity 2010年第4期23卷 804-814页

作者： Liyong SHEN Chunming YUAN School of Mathematical sciences Graduate University Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Mathematics Mechanization Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Among several implicitization methods, the method based on resultant computation is a simple and direct one, but it often brings extraneous factors which are difficult to remove. This paper studies a class of rational space curves and rational surfaces by implicitization with univaxiate resultant computations. This method is more efficient than the other algorithms in finding implicit equations for this class of rational curves and surfaces.

关键词： Implicitization rational space curves rational surfaces resultants.

Simulation of aerodynamic performance affected by vortex generators on blunt trailing-edge airfoils

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science china(Technological sciences) 2010年第1期53卷 1-7页

作者： YANG Ke1,2,ZHANG Lei1,3 & XU JianZhong1,2 1 institute of Engineering Thermophysics,chinese academy of sciences,beijing 100190,china 2 Key Laboratory of Wind Energy Utilization,chinese academy of sciences,beijing 100190,china 3 Graduate School of chinese academy of sciences,beijing 100190,china 1. institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China2. Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing 100190 China3. Graduate School of Chinese Academy of Sciences Beijing 100190 China

An investigation was carried out by numerical simulation on a wind turbine airfoil and a blunt trailing-edge airfoil with and without vortex generators (VGs), and the performance of the airfoils was analyzed. By the simulation of airfoil DU 91-W2-250 it was verified that the numerical method and model were credible. Based on this airfoil, a new one with a blunt trailing edge of 6% chord was blended by symmetrically adding thickness, and its characteristics curves were obtained through computing at key angles of attack. Additionally, the pressure distribution on blended airfoil was analyzed by comparing to the airfoil without blend. The interaction of streamwise vortices induced by VGs with trailing vortex or separation vortex was considered, followed by the uncovery of how VGs can suppress the boundary layer separation.

关键词： vortex generators airfoil blunt trailing-edge

On the contact width in generalized plain strain JKR model for isotropic solids

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Acta Mechanica Sinica 2009年第4期25卷 491-497页

作者： Cong Yan Shaohua Chen LNM, institute of Mechanics, chinese academy of sciences,100190 beijing. china LNM Institute of Mechanics Chinese Academy of Sciences 100190 Beijing China

Adhesive contact model between an elastic cylinder and an elastic half space is studied in the present paper, in which an external pulling force is acted on the above cylinder with an arbitrary direction and the contact width is assumed to be asymmetric with respect to the structure. Solutions to the asymmetric model are obtained and the effect of the asymmetric contact width on the whole pulling process is mainly discussed. It is found that the smaller the absolute value of Dundurs＇ parameter 13 or the larger the pulling angle O, the more reasonable the symmetric model would be to approximate the asymmetric one.

关键词： Contact mechanics Generalized JKRmodel Asymmetric contact width Oscillatory solution Non-oscillatory solution

A CRITERION FOR TESTING WHETHER A DIFFERENCE IDEAL IS PRIME

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Journal of systems science & Complexity 2009年第4期22卷 627-635页

作者： Chunming YUAN Xiao-Shan GAO Key Laboratory of Mathematics Mechanization,institute of systems science academy of Mathematics and systems science,chinese academy of sciences,beijing 100190,china. Key Laboratory of Mathematics Mechanization Institute of Systems Science Beijing China academy of Mathematics and systems science Chinese Academy of Sciences Beijing 100190 China

This paper presents a criterion for testing the irreducibility of a polynomial over an algebraicextension *** this criterion and the characteristic set method,the authors give a criterion fortesting whether certain difference ascending chains are strong irreducible,and as a consequence,whetherthe saturation ideals of these ascending chains are prime ideals.

关键词： Characteristic set difference prime ideal irreducibility strong irreducibility.

Local canonical correlation coefficients and canonical variables of groups of random variables

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chinese science Bulletin 1998年第10期43卷 815-817页

作者： XU Xingzhong institute of systems science, chinese academy of sciences, beijing 100080, china institute of systems science Chinese Academy of Sciences Beijing China

The concepts of local correlation coefficient, local canonical correlation coefficients and local canonical variables of groups of random variables are defined, which generalize the classical concepts in two groups of random *** concepts together with total corresponding concepts clarify the correlativity among groups of random variables.

关键词： groups of random variables covariance matrix local canonical correlation coefficients local canonical variables.