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Series-based approximate approach of optimal tracking control for nonlinear systems with time-delay

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Progress in Natural science:Materials International 2008年第12期18卷 1571-1576页

作者： Gongyou Tang~a Mingqu Fan~(a,b) a college of Information science and Engineering,Ocean University of China,Qingdao 266100,China b college of Information and Engineering,Shandong University of science and Technology,Jinan 250031,China [a]college of Information science and Engineering Ocean University of China Qingdao 266100 China [b]college of Information and Engineering Shandong University of Science and Technology Jinan 250031 China

The optimal output tracking control (OTC) problem for nonlinear systems with time-delay is *** a series-based approx- imate approach,the original OTC problem is transformed into iteration solving linear two-point boundary value problems without time- *** OTC law obtained consists of analytical linear feedback and feedforward terms and a nonlinear compensation term with an infinite series of the adjoint *** truncating a finite sum of the adjoint vector series,an approximate optimal tracking control law is obtained.A reduced-order reference input observer is constructed to make the feedforward term physically *** exam- ples are used to test the validity of the series-based approximate approach.

关键词： Nonlinear systems Time-delay Tracking control Optimal control Observer

A Raw Signal Simulator for Bistatic SAR

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Chinese Journal of Aeronautics 2009年第4期22卷 434-443页

作者： Xia Weijie,Zhou Jianjiang college of Information science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China [a]college of Information science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

This article proposes a new efficient raw signal simulator for the bistatic synthetic aperture radar （SAR） based on 2D fast Fourier transform （FFT） to deal with cases of both ideal trajectory and trajectory deviation. It begins with analyzing the geometric configuration and the range history of the bistatic SAR in side-looking and squint modes of ideal trajectory as well as trajectory deviation. Then a detailed and mathematical study is conducted on the equivalence relation of bistatic-to-monostatic applications （BTMA） in the case of ideal trajectory and trajectory deviation. Also a set of formulas are derived for the equivalence relation between bistatic SAR and monostatic SAR on some reasonable assumptions. Therefore, the application of the simulation method based on the 2D FFT for the monostatic SAR can be extended to the case of bistatic SAR. Finally, the simulation results prove the validity of this method. By comparing the efficiency of the proposed method with that of the time domain method, it is shown that the former is a few orders of magnitude higher.

关键词： bistatic synthetic aperture radar raw signal simulation fast Fourier transform

Finite automata based on quantum logic and monadic second-order quantum logic

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science China(Information sciences) 2010年第1期53卷 101-114页

作者： LI YongMing college of Computer science, Shaanxi Normal University, Xi’an 710062, China 1. college of Computer science Shaanxi Normal University Xi’an 710062 China

We introduce monadic second-order quantum logic and prove that the behaviors of finite automata based on quantum logic are precisely the quantum languages definable with sentences of our monadic secondorder quantum logic. This generalizes Büchi’s and Elgot’s fundamental theorems to quantum logic setting. We also consider first-order quantum logic and show that star-free quantum languages and aperiodic quantum languages introduced here coincide with the first-order quantum definable ones. This generalizes Schützenberger’s fundamental theorems to quantum logic setting. The determinazation of finite automata based on quantum logic is studied by introducing the generalized subset construction method. Then the Kleene theorem in the frame of quantum logic is presented here.

关键词： quantum logic finite automaton monadic second quantum logic quantum language quantum computation Kleene theorem

INFILTRATION KINETICS MODEL OF LIQUID METAL INTO A FIBROUS PREFORM IN CENTRIFUGAL ACCELERATING FIELD

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Chinese Journal of Mechanical Engineering 2001年第4期14卷 293-296页

作者： Zhang Xinping,Yu Sirong,He Zhenming (college of Materials science and Engineering,Jilin University) 吉林大学吉林

The infiltration kinetics of the metal melt into a fibrous preform in centrifugal accelerating field is analyzed on the basis of Darcy's law and the assumption that the fibrous preform is treated as 'bundle of capillaries' The critical rotating speed is analyzed with the established model The influences of the metal melt mass,the rotating speed of the equipment,the casting height, the original outer radius of the metal melt and the fibrous volume fraction in fibrous preform on infilatration are studied The results show that the critical rotating speed is dependent on critical pressure, casting height, metal melt mass and the character of fibrous preform With the increase in the metal melt mass, rotating speed of the equipment and original outer radius of the metal melt, or the decrease in casting height and fibrous volume fraction in fibrous of the metal melt,or the decrease in casting height and fibrous volume fraction in fibrous preform,infiltration of metal melt for fibrous preform becomes easier.

关键词： Centrifugal accelerating field Metal melt Fiber Infiltration kinetics Metal matrix composite

A new generation of plastic optical fibers and its functional exploiting

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science China(Technological sciences) 2008年第12期51卷 2197-2207页

作者： YU RongJin & ZHANG Bing college of Information science and Engineering,Yanshan University,Qinhuangdao 066004,China college of Information science and Engineering Yanshan University Qinhuangdao 066004 China

A major problem of plastic optical fibers(POFs) is large transmission loss in comparison with silica *** adopting a new optical fiber structure,hollow-core Bragg fiber with cobweb-structured cladding,which can suppress the absorption losses of constituent materials by a factor of about 104―106,the problem of POFs with large losses is solved *** the advantage of flexibility and easy bending,the POFs with this structure can guide light with low transmission loss for information and energy in the wavelength range of visible light to terahertz(THz) wave(0.4―1000 μm).This new generation of POFs will find many applications.

关键词： plastic optical fiber hollow-core Bragg fiber cobweb-structured cladding visible light infrared light terahertz wave circular-polarization single-mode

Approximately optimal tracking control for discrete time-delay systems with disturbances

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Progress in Natural science:Materials International 2008年第2期18卷 225-231页

作者： Gongyou Tang a,,Huiying Sun b,Haiping Pang c a college of Information science and Engineering,Ocean University of China,Qingdao 266100,China b college of Information and Electrical Engineering,Shandong University of science and Technology,Qingdao 266510,China c college of Automation and Electronic Engineering,Qingdao University of science and Technology,Qingdao 266042,China college of Information science and Engineering Ocean University of China Qingdao 266100 China college of Information and Electrical Engineering Shandong University of Science and Technology Qingdao 266510 China college of Automation and Electronic Engineering Qingdao University of Science and Technology Qingdao 266042 China

Optimal tracking control (OTC) for discrete time-delay systems affected by persistent disturbances with quadratic performance index is considered. By introducing a sensitivity parameter,the original OTC problem is transformed into a series of two-point boundary value (TPBV) problems without time-advance or time-delay terms. The obtained OTC law consists of analytic feedforward and feedback terms and a compensation term which is the sum of an infinite series of adjoint vectors. The analytic feedforward and feedback terms can be found by solving a Riccati matrix equation and two Stein matrix equations. The compensation term can be obtained by using an iteration formula of the adjoint vectors. Observers are constructed to make the approximate OTC law physically realizable. A simulation example shows that the approximate approach is effective in tracking the reference input and robust with respect to exogenous persistent disturbances.

关键词： Discrete systems Time-delay systems Disturbances Optimal control Tracking control

File Assignment Policy in Network Storage System

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Wuhan University Journal of Natural sciences 2003年第4A期8卷 1075-1080页

作者： Cao Qiang, Xie Chang-sheng college of Computer science and Technology, Huazhong University of science and Technology, Wuhan 430074, Hubei, China Huazhong University of science and Technology College of Computer Science and Technology Wuhan Hubei China (GRID:grid.33199.31) (ISNI:***)

Network storage increase capacity and scalability of storage system, data availability and enables the sharing of data among clients. When the developing network technology reduce performance gap between disk and network, however, mismatched policies and access pattern can significantly reduce network storage performance. So the strategy of data placement in system is an important factor that impacts the performance of overall system. In this paper, the two algorithms of file assignment are presented. One is Greed partition that aims at the load balance across all NADs (Network Attached Disk). The other is Sort partition that tries to minimize variance of service time in each NAD. Moreover, we also compare the performance of our two algorithms in practical environment. Our experimental results show that when the size distribution (load characters) of all assigning files is closer and larger, Sort partition provides consistently better response times than Greedy algorithm. However, when the range of all assigning files is wider, there are more small files and access rate is higher, the Greedy algorithm has superior performance in compared with the Sort partition in off-line.

关键词： file assignment network storage network attached disk

Immobilized chitosan as a selective absorbent for the nickel removal in water sample

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Journal of Environmental sciences 2003年第5期15卷 633-638页

作者： WU Jian min, WANG Yong yao (Department of Chemistry, college of science, Zhejiang University, Hangzhou 310027, China. ) Department of Chemistry College of Science Zhejiang University Hangzhou 310027 Chin

Method for preparation of chitosan immobilized on silica gel(CTS silica) was described. The CTS silica was used as absorbent for the absorption of nickel in water. The results showed that this absorbent had relatively high selectivity and strong affinity to nickel. The maximum absorption capacity for nickel can reach 667 mg/g of chitosan. Factors that affect the absorption capacity, such as pH, ion strength and the presence of calcium, EDTA and the mechanism of absorption were discussed in detail. The absorbent can be regenerated with acid and reused for several times. The recovery rate for nickel can reach 99 99%. This absorbent filled in a column can be used in nickel removal from wastewater and drinking water.

关键词： immobilized chitosan nickel wastewater treatment

Heteroclinic orbits and heteroclinic chains for a discrete Hamiltonian system

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science China Mathematics 2010年第6期53卷 1555-1564页

作者： ZHANG Hao & LI ZhiXiang Department of Mathematics and Systems science,college of science,National University of Defense Technology,Changsha 410073,China 1. Department of Mathematics and Systems science College of Science National University of Defense Technology Changsha 410073 China

In the present work we prove some existence results of heteroclinic orbits and heteroclinic chains for a second order discrete Hamiltonian system of the form Δ2q(t-1)+V(q(t))=0,t∈*** methods we use are variational in *** results show that under general conditions,for each maximum point β of V,the above system possesses multiple heteroclinic orbits joining β and some other maximum points of *** also prove that for any pair of distinct maximum points η and ξ of V,there exists at least one heteroclinic chain from η to ξ.

关键词： difference equation heteroclinic orbit heteroclinic chain variational method