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Second-order consensus in networks of dynamic agents with communication time-delays

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Journal of Systems engineering and Electronics 2010年第1期21卷 88-94页

作者： Bo Yang1,2, Huajing Fang3. and Hua Wang4 1. School of Navigation, wuhan university of technology, wuhan 43.063. P. R. china 2. wuhan Second Ship Design and Research Institute, wuhan 43.064, P. R. china 3. Department of Control Science and engineering, Huazhong university of Science and technology, wuhan 43.074, P. R. china 4. Department of Aerospace and {13. engineering, Boston university, Boston MA02215, USA School of Navigation Wuhan University of Technology Wuhan 430063 P. R. China wuhan Second Ship Design and Research Institute Wuhan 430064 P. R. China Department of Control Science and engineering Huazhong University of Science and Technology Wuhan 430074 P. R. China Department of Aerospace and mechanical engineering Boston University Boston MA02215 USA

This paper proposes second-order consensus protocols with time-delays and gives the measure of the robustness of the protocols to the time-delay existing in the network of agents with second-order dynamics. By employing a frequency domain method, it is proven that the information states and their time derivatives of all the agents in the network achieve consensus asymptotically, respectively, for appropriate communication timedelay if the topology of weighted network is connected. Particularly, a tight upper bound on the communication time-delay that can be tolerated in the dynamic network is found. The consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between neighboring agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results for second-order consensus in networks in the presence of communication time-delays.

关键词： second-order consensus protocols dynamic networks algebraic graph theory frequency domain analysis com-munication constraints.

Fuzzy Comprehensive Evaluation for Decision Making of Water Saving Irrigation System

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wuhan university Journal of Natural Sciences 2003年第3A期8卷 837-841页

作者： Luo Jin\|yao, Qiu Yuan\|feng college of Water Resources and Hydropower engineering , wuhan {3., wuhan 43.072, hubei, china college of Water Resources and Hydropower engineering Wuhan University Wuhan Hubei China

A model of fuzzy comprehensive evaluation for water saving irrigation system (WSIS) decision making is proposed based on establishing an index system affected by six kinds of basic factors including qualitative and quantitative indexes. The object function of WSIS is set up by using the concept of fuzzy membership degree, it is to transform characteristic vector matrix into unify membership matrix and extending the least square method to the least of weighted distance square. The optimum weighted membership degree and the inferior weighted membership degree are used to solve the object function. This method effective solves the problem of classify for fuzzy attributive indexes and the problem of optimum for the set of different attributive indexes. A case study shows that the fuzzy comprehensive evaluation model is reasonable and effective in decision making for water saving irrigation system planning.

关键词： water saving irrigation system (WSIS) decision making fuzzy comprehensive evaluation (FCE) index system fuzzy membership degree

APPROACH ON INTELLIGENT OPTIMIZATION DESIGN BASED ON COMPOUND KNOWLEDGE

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Chinese Journal of mechanical engineering 2003年第3期16卷 300-304页

作者： Yao Jianchu Zhou JiYu JunSchool of mechanical Scienceand engineering,Huazhong university of Scienceand {3.,wuhan 43.074, china School of mechanical Science and engineering Huazhong University of Science and Technology Wuhan 430074

A concept of an intelligent optimal design approach is proposed, which isorganized by a kind of compound knowledge model. The compound knowledge consists of modularizedquantitative knowledge, inclusive experience knowledge and case-based sample knowledge. By usingthis compound knowledge model, the abundant quantity information of mathematical programming and thesymbolic knowledge of artificial intelligence can be united together in this model. The intelligentoptimal design model based on such a compound knowledge and the automatically generateddecomposition principles based on it are also presented. Practically, it is applied to theproduction planning, process schedule and optimization of production process of a refining &chemical work and a great profit is achieved. Specially, the methods and principles are adaptablenot only to continuous process industry, but also to discrete manufacturing one.

关键词： Intelligent optimization Automatic modeling Compound knowledge Expertsystem

Robust H-infinity fuzzy control for uncertain Markovian jump nonlinear singular systems with wiener process

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控制理论与应用（英文版） 2010年第2期8卷 205-210页

作者： Aiqing ZHANG 1 , Huajing FANG 2 (1.college of Mathematics and Computer Science, Jianghan university, wuhan {3. 43.056, china 2.Department of Control Science and engineering, Huazhong university of Science and technology, wuhan {3. 43.074, china) college of Mathematics and Computer Science Jianghan University Wuhan Hubei China Department of Control Science and engineering Huazhong University of Science and Technology Wuhan Hubei China

This paper deals with the problems of robust stochastic stabilization and H-infinity control for Markovian jump nonlinear singular systems with Wiener process via a fuzzy-control approach. The Takagi-Sugeno (T-S) fuzzy model is employed to represent a nonlinear singular system. The purpose of the robust stochastic stabilization problem is to design a state feedback fuzzy controller such that the closed-loop fuzzy system is robustly stochastically stable for all admissible uncertainties. In the robust H-infinity control problem, in addition to the stochastic stability requirement, a prescribed performance is required to be achieved. Linear matrix inequality (LMI) sufficient conditions are developed to solve these problems, respectively. The expressions of desired state feedback fuzzy controllers are given. Finally, a numerical simulation is given to illustrate the effectiveness of the proposed method.

关键词： Fuzzy control H-infinity control Singular systems Stochastic stability Linear matrix inequality (LMI)

Surface Nanocrystallization of Magnesium Alloy AZ91D by High-Energy Shot Peening

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Journal of wuhan university of technology(Materials Science) 2009年第4期24卷 515-519页

作者：张津 School of Materials Science & engineering University of Science and Technology Beijing college of Materials Science & engineering Chongqing University of Technology

High-energy shot peening （HESP）, a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The mi- crostructure evolution was conducted using X-ray diffraction （XRD） and field emission scanning electronic microscopy （FESEM）. The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100℃ for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400℃ for 1 h.

关键词： AZ91 D surface nanocrystallization HESP microhardnss corrosion resistance

GEAR CRACK EARLY DIAGNOSIS USING BISPECTRUM DIAGONAL SLICE

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Chinese Journal of mechanical engineering 2003年第2期16卷 193-196页

作者： Li WeihuaZhang GuicaiShi TielinYang ShuziSchool of mechanical Scienceand engineering,Huazhong university of Scienceand {3.,wuhan 43.074, china School of mechanical Science and engineering Huazhong University of Science and Technology Wuhan 430074

A study of bispectral analysis in gearbox condition monitoring is *** theory of bispectrum and quadratic phase coupling (QPC) is first introduced, and then equationsfor computing bispectrum slices are obtained. To meet the needs of online monitoring, a simplifiedmethod of computing bispectrum diagonal slice is adopted. Industrial gearbox vibration signalsmeasured from normal and tooth cracked conditions are analyzed using the above method. Experimentsresults indicate that bispectrum can effectively suppress the additive Gaussian noise andchracterize the QPC phenomenon. It is also shown that the 1-D bispectrum diagonal slice can capturethe non-Gaussian and nonlinear feature of gearbox vibration when crack occurred, hence, this methodcan be employed to gearbox real time monitoring and early diagnosis.

关键词： condition monitoring gear crack early diagnosis quadratic phase coupling bispectrum diagonal slice

COMPUTER VISION APPLIEDIN THE PRECISION CONTROL SYSTEM

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Chinese Journal of mechanical engineering 2002年第1期15卷 87-89页

作者： Zhang Qingying Logistics engineering Department，wuhan university of {3.，wuhan 43.063.china Logistics engineering Departiment Wuhan University of Technology Wuhan 430063

Computer vision and its application in the precision control system arediscussed. In the process of fabricating, the accuracy of the products should be controlledreasonably and completely. The precision should be kept and adjusted according to the information offeedback got from the measurement on-line or out-line in different procedures. Computer vision isone of the useful methods to do this. Computer vision and the image manipulation are presented, andbased on this, a n-dimensional vector to appraise on precision of machining is given.

关键词： Computer vision Measurement Precision Quality of products

Development and Physical Properties of Film of Wheat Gluten Cross-linked by Transglutaminase

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Journal of wuhan university of technology(Materials Science) 2005年第1期20卷 78-82页

作者：王金水 college of Food and Bioengineering South China University of TechnologyGuang zhou 510641China The Faculty of Food engineering Henan University of TechnologyZhengzhou 450052China

Films were developed from the modified wheat glutens by microbial transglutamina se(MTGase, [E/S]=10u/g,15u/g and 20u/g) in order to improve physical and barri er properties of the *** was used as a *** films prepared from the modified-glutens by MTGase show a lower elongation at break(E) and a water vapor permeability(WVP), and a higher tensile strength(TS) than the nati ve gluten *** the modified gluten films by different concentrations of MT Gase are immersed in water at 25℃,their weight losses decreased significantly, and their water resistance increases obviously as expected, compared with the c ontrol gluten films. Moreover, an addition of glycerol as plasticizer greatly mo dified water vapor barrier and mechanical properties of the films.

关键词： wheat gluten microbial transglutaminase barrier properties tensile strengt h elongation at break

Kinetics analysis of volume phase transition of intelligent neutral thermo-sensitive hydrogels

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Science china(Physics,Mechanics & Astronomy) 2008年第5期51卷 532-540页

作者： WANG XiaoGui1 & LI YiQuan2 1 college of mechanical engineering,Zhejiang {3. of technology,Hangzhou 3.003.,china 2 School of mechanical & Electronic engineering,Changchun {3. of Science and technology,Changchun 13.022,china college of mechanical engineering Zhejiang University of Technology Hangzhou China School of mechanical & Electronic engineering Changchun University of Science and Technology Changchun China

In this work,utilizing the first law of thermodynamics and the Flory mean-field theory,the kinetic deformation studies concerning the volume phase transition of the neutral thermo-sensitive hydrogels were performed *** hydrogel was assumed as a biphasic mixture medium in the framework of the continuum mixture *** the energy conservation of the thermodynamics system of the hydrogel,the governing equations for the kinetics of the nonlinear large deforma-tion were *** explicit analytical expressions of the effective stress tensor and the chemical potential of the fluid of the thermo-sensitive hydrogel PNIPA were also obtained from the Helmholtz free energy,which can model the steady-static volume phase transition quantitatively.

关键词： thermo-sensitive hydrogel volume phase transition effective stress energy conservation