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Birefringence of (Al)GaAs/AlGaAs multiplequantum well optical waveguides

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Chinese Journal of Lasers 1994年第4期B3卷 331-337页

作者： MA Chunsheng(department of electronic engineering, National Integrated Optoelectronics Laboratory,Jinn University, Changchon 13.023. China) Jilin Univ Changchun China

Ｂｉｒｅｆｒｉｎｇｅｎｃｅｏｆ（Ａｌ）ＧａＡｓ／ＡｌＧａＡｓｍｕｌｔｉｐｌｅｑｕａｎｔｕｍｗｅｌｌｏｐｔｉｃａｌｗａｖｅｇｕｉｄｅｓ￥ＭＡＣｈｕｎｓｈｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｏｎｉｃＥｎｇｉｎｅｅ... 详细信息

Ｂｉｒｅｆｒｉｎｇｅｎｃｅｏｆ（Ａｌ）ＧａＡｓ／ＡｌＧａＡｓｍｕｌｔｉｐｌｅｑｕａｎｔｕｍｗｅｌｌｏｐｔｉｃａｌｗａｖｅｇｕｉｄｅｓ￥ＭＡＣｈｕｎｓｈｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｏｎｉｃＥｎｇｉｎｅｅｒｉｎｇ，ＮａｔｉｏｎａｌＩｎｔｅ...

关键词： multiple quantum well optical wavesuide birefringence

Mapping and overlapping based carrier frequency searching technique for rapid GNSS long PN-code acquisition

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Science China(Information Sciences) 2010年第12期53卷 2642-2652页

作者： LI Hong ,LU MingQuan & FENG ZhenMing department of electronic engineering,Tsinghua University,Beijing 100084,China department of electronic engineering Tsinghua University Beijing China

In global navigation satellite systems(GNSS),because of the long period and high chip rate of long pseudo-noise(PN) code,the rapid acquisition is hard to *** speed up search process,in the paper,a mapping and overlapping based carrier frequency searching technique is *** mapping incoming signals of the same interval to different carrier frequency cells and overlapping together the mapped incoming signals that correspond to the same code phase,the technique reduces the number of the cells to be *** effect of the technique on detection and mean acquisition time performance is *** is shown that the technique reduces the cells to be searched and shortens mean acquisition time at the expense of degrading detection *** technique is fit to the previously published acquisition methods and is capable of improving their mean acquisition time *** and simulation results validate the analysis.

关键词： carrier frequency cells mapping overlapping acquisition performance

The normal numbers of the fuzzy systems and their classes

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Science China(Information Sciences) 2010年第11期53卷 2215-2229页

作者： LI HongXing1,3. YUAN XueHai1, WANG JiaYin2 & LI YuCheng3.1Faculty of electronic Information and electrical engineering, Dalian University of Technology, Dalian 116024, China 2School of Mathematical Sciences, Beijing Normal University, Beijing 100875, China 3.3. of Automation, North China University of Technology, Beijing 100144, China Faculty of electronic Information and electrical engineering Dalian University of Technology Dalian China department of Automation North China University of Technology Beijing China School of Mathematical Sciences Beijing Normal University Beijing China

R-fuzzy set is defined in this paper, which is regarded as the generalization of the Zadeh fuzzy set. By means of CRI method, some fuzzy systems are constructed by suitably using several kinds of R-fuzzy sets as fuzzy inference antecedents, such as interpolation fuzzy system, Bernstein fuzzy system, Lagrange fuzzy system and Hermite fuzzy system. A notion of the normal number of the fuzzy system is defined here, we have shown that all fuzzy systems are able to be classified as three classes such as the normal fuzzy systems, the regular fuzzy systems and the singular fuzzy systems under the significance of the normal numbers of fuzzy systems. Finally, the generalized Bernstein polynomial is obtained by constructing Bernstein fuzzy system, it is proved that the generalized Bernstein polynomial is uniformly convergent in C[a,b] under a weaker condition, and it is pointed out that there exist generalized Bernstein polynomials to be not convergent in C[a,b] by use of constructing a counterexample.

关键词： R-fuzzy set fuzzy system the normal number of fuzzy system universal approximation property for fuzzy system

Research on resolution between multi-component LFM signals in the fractional Fourier domain

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Science China(Information Sciences) 2012年第6期55卷 1301-1312页

作者： LIU Feng 1,XU HuiFa 1,2,TAO Ran 3.& WANG Yue 3.1 department of electronic and Information engineering,Naval Aeronautical engineering Institute,Yantai 264001,China 2 The 943.2 th Unit of People's Liberation Army,Qingdao 266111,China 3.School of Information Science and Technology,Beijing Institute of Technology,Beijing 100081,China department of electronic and Information engineering Naval Aeronautical Engineering Institute Yantai China The 943.2th Unit of People’s Liberation Army Qingdao China School of Information Science and Technology Beijing Institute of Technology Beijing China

When the initial frequencies and chirp rates of multi-component linear frequency modulation (LFM or chirp) signals are close,the signals may not be distinguished in the fractional Fourier domain (FRFD).Consequently,some signals cannot be *** this paper,first,the spectral distribution characteristics of a continuous LFM signal in the FRFD are analyzed,and then the spectral distribution characteristics of a LFM signal in the discrete FRFD are ***,the critical resolution distance between the peaks of two LFM signals in the FRFD is deduced,and the relationship between the dimensional normalization parameter and the distance between two LFM signals in the FRFD is also *** is discovered that selecting a proper dimensional normalization parameter can increase the ***,a method to select the parameter is proposed,which can improve the resolution ability of the fractional Fourier transform (FRFT).Its effectiveness is verified by simulation results.

关键词： fractional Fourier transform LFM signal signal resolution

Effect of rare earths on phase transformation in as-cast ZA27 alloy dur-ing compressive creep

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Rare Metals 2003年第4期22卷 259-264页

作者： WEIXiaowei SHENBaoluo DepamnentofAppliedPhysics UniversityofElectronicScienceandTechnologyofChinaChengdu610045China DeparlanentofMetalScience SichuanUniversityChengdu610065China

The effect of the mixed rare earths of Ce on the phase transformation in ascast ZA 27 alloy during compressive was investigated under 3. MPa and at 160 deg C by X-raydiffraction technique and SEM. The results showed that the as cast microstructure of ZA 27-RE alloyconsisted of a dendritic Al-rich alpha' surrounded by Zn-rich beta' phase, interdendritic epsilonphase and Zn-rich eta phase together with a complex Z phase which was a complex constitute compound,(RE,Cu)Al_5Zn_(16), dispersed in crystal interfaces or branch crystal interfaces and stable duringcompressive creep test at 160 deg C. The phase transformations of ZA 27-RE alloy, decomposition ofbeta' phase arid four transformation, were delayed by the addition of rare earths, also the lamellarstructure and the spheroidized structure in ZA 27-RE alloy were finer than in ZA 27 alloy duringcompressive creep test at 160 deg C at the same creep time, and the compressive creep resistance ofZA 27-RE alloy was higher than that of ZA 27 alloy.

关键词： microstructure change compressive creep rare earths ZA 27 alloy

ROBUSTNESS ANALYSIS OF LEADER-FOLLOWER CONSENSUS

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Journal of Systems Science & Complexity 2009年第2期22卷 186-206页

作者： Jinzhi WANG Ying TAN · Iven MAREELS State Key Laboratory for Turbulence and Complex System and department of Mechanics and Aerospace Engi-neering College of Engineering Peking University Beijing 100871 China. Departmen~ of electrical and electronic engineering University of Melbourne Melbourne VIC. 3010 Aus-tralia.

In this paper,robustness properties of the leader-follower consensus are *** of presentation,the attention is focused on a group of continuous-time first-order dynamicagents with a time-invariant communication topology in the presence of communication *** orderto evaluate the robustness of leader-follower consensus,two robustness measures are proposed:the L_2gain of the error vector to the state of the network and the worst case L_2 gain at a *** L_2 gain of the error vector to the state of the network is widely used in robust control design andanalysis,the worst case L_2 gain at a node is less conservative with respect to the number of nodes inthe *** is thus suggested that the worst case L_2 gain at a node is used when the robustnessof consensus is *** analysis and simulation results show that these two measuresare sensitive to the communication *** general,the 'optimal' communication topology thatcan achieve most robust performance with respect to either of the proposed robustness measures isdifficult to characterize and/or *** the in-degree of each follower is one,it is shown thatboth measures reach a minimum when the leader can communicate to each node in the network.

关键词： Communication errors leader-follower consensus robustness.

New method for computing unstable equilibrium points of power systems with induction motors

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Science China(Technological Sciences) 2010年第4期53卷 881-885页

作者： CHEN Lei,XU Fei & MIN Yong State Key Lab of Power Systems,department of electrical engineering,Tsinghua University,Beijing 100084,China State Key Lab of Power Systems Department of Electrical Engineering Tsinghua University Beijing China

The computation of the unstable equilibrium point(UEP) is a key step involved in stability region estimation of nonlinear dynamic systems.A new continuation-based method to compute the UEPs of a power system with induction motors is *** mechanical torques of motors are changed to form a parameterized equation *** the solution curve of the equation set is traced by the continuation method from the stable equilibrium point to a *** direction of mechanical torque change is varied to get multiple *** obtained UEPs are mostly *** fast assessment of induction motor stability is studied by approximating the stable manifolds of the *** method is tested in several systems and satisfactory results are obtained.

关键词： power system stability transient voltage stability unstable equilibrium point(UEP) stability boundary induction motor

Dynamic scheduling model of computing resource based on MAS cooperation mechanism

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Science in China(Series F) 2009年第8期52卷 1302-1320页

作者： JIANG WeiJin1,2, ZHANG LianMei3.& WANG Pu4 1 School of Computer and electronic engineering, Hunan University of Commerce, Changsha 410205, China 2 School of Information engineering, Xiangtan University, Xiangtan 411000, China 3.{3. engineering College, Wuhan University, Wuhan 43.072, China 4 School of Commerce, Central South University, Changsha 410083. China School of Computer and electronic engineering Hunan University of Commerce Changsha China School of Information engineering Xiangtan University Xiangtan China electrical engineering College Wuhan University Wuhan China School of Commerce Central South University Changsha China

Allocation of grid resources aims at improving resource utility and grid application performance. Currently, the algorithms proposed for this purpose do not fit well the autonomic, dynamic, distributive and heterogeneous features of the grid environment. According to MAS （multi-agent system） cooperation mechanism and market bidding game rules, a model of allocating allocation of grid resources based on market economy is introduced to reveal the relationship between supply and demand. This model can make good use of the studying and negotiating ability of consumers＇ agent and takes full consideration of the consumer＇s behavior, thus rendering the application and allocation of resource of the consumers rational and valid. In the meantime, the utility function of consumer is given; the existence and the uniqueness of Nash equilibrium point in the resource allocation game and the Nash equilibrium solution are discussed. A dynamic game algorithm of allocating grid resources is designed. Experimental results demonstrate that this algorithm diminishes effectively the unnecessary latency, improves significantly the smoothness of response time, the ratio of throughput and resource utility, thus rendering the supply and demand of the whole grid resource reasonable and the overall grid load balanceable.

关键词： multi-agent system (MAS) resource scheduling model evolutionary game cooperation mechanism utility function

A Method for Head-shoulder Segmentation and Human Facial Feature Positioning

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通信学报 1998年第5期 29-34页

作者： Hu Tianjian Cai Dejun department of electrical and Information engineering (Huazhong University of Science and Technology, Wuhan 43.074)

ＡＭｅｔｈｏｄｆｏｒＨｅａｄｓｈｏｕｌｄｅｒＳｅｇｍｅｎｔａｔｉｏｎａｎｄＨｕｍａｎＦａｃｉａｌＦｅａｔｕｒｅＰｏｓｉｔｉｏｎｉｎｇＨｕＴｉａｎｊｉａｎＣａｉＤｅｊｕｎＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｉｃａｌａ... 详细信息

ＡＭｅｔｈｏｄｆｏｒＨｅａｄｓｈｏｕｌｄｅｒＳｅｇｍｅｎｔａｔｉｏｎａｎｄＨｕｍａｎＦａｃｉａｌＦｅａｔｕｒｅＰｏｓｉｔｉｏｎｉｎｇＨｕＴｉａｎｊｉａｎＣａｉＤｅｊｕｎＤｅｐａｒｔｍｅｎｔｏｆＥｌｅｃｔｒｉｃａｌａｎｄＩｎｆｏｒｍａｔｉｏｎＥｎｇｉ...

关键词： model based image coding head shoulder segmentation facial feature extraction model adaptation edge detection.