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A note on the crossed product R(A, α) associated with PSL_2(R)

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science china Mathematics 2008年第11期51卷 2081-2088页

作者： WU WenMing 1 school of Mathematical and Computer science, Chongqing normal university, Chongqing 400047, china 2 Department of Mathematical science, Tsinghua university, Beijing 100084, china school of Mathematical and Computer science Chongqing Normal University Chongqing China Department of Mathematical science Tsinghua University Beijing China

Given the hyperbolic measure dxdy/y2 on the upper half plane H, the rational actions of PSL2(R) on H induces a continuous unitary representation α of this group on the Hilbert space L2(H, dxdy/y2). Supposing that A = {Mf : f ∈ L∞(H, dxdy/y2)}, we show that the crossed product R(A,α) is of type I. In fact, the crossed product R(A,α) is *-isomorphic to the von Neumann algebra B(L2(P,ν))■LK, where LK is the abelian group von Neumann algebra generated by the left regular representation of K.

关键词： crossed product rational actions PSL2(R) von Neumann algebras

ENERGY FLOWS IN COMPLEX ECOLOGICAL SYSTEMS:A REVIEW

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Journal of Systems science & Complexity 2009年第3期22卷 345-359页

作者： Jiang ZHANG Department of Systems science,school of Management,Beijing normal university,Beijing 100875,china. Department of Systems science School of Management Beijing Normal University Beijing 100875 China

Energy flow drives the complex systems to *** allometric scaling as the universalenergy flow pattern has been found in different scales of ecological *** reflects the generalpower law relationship between flow and *** underlying mechanisms of energy flow patterns areexplained as the branching transportation networks which can be regarded as the result of systematicoptimization of a biological target under *** flows in the ecological system may bemodelled by the food web model and population dynamics on the *** paper reviews thelatest progress on the energy flow patterns,explanatory models for the allometric scaling and modellingapproach of flow and network evolution dynamics in ***,the possibility of generalizingthese flow patterns,modelling approaches to other complex systems is discussed.

关键词： Allometric scaling energy flow flows in complex systems food web.

H∞ control for uncertain Markovian jump systems with mode-dependent mixed delays

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Progress in Natural science:Materials International 2008年第3期18卷 309-314页

作者： Yingchun Wang, Huaguang Zhang school of information science and engineering, Northeastern university, Shenyang 110004, china school of information science and engineering Northeastern University Shenyang 110004 China

We study the problem of H∞control for a class of Markovian jump systems with norm-bounded parameter uncertainties and mode- dependent mixed delays including discrete delays and distributed delays in this paper. Our aim is to present a new delay-dependent con- trol approach such that the resulting closed-loop system is robust mean-square (MS) exponentially stable and satisfies a prescribed H∞performance level, irrespective of the parameter uncertainties. Such delay-dependent approach does not require system transformation or free-weighting matrix. A numerical example shows that the results are less conservative and more effective.

关键词： H1 control Markovian jump Mixed delays Delay-dependent criterion

Level Set interface treatment and its application in Euler method

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science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 227-236页

作者： WU KaiTeng1,2,HAO Li3,WANG Cheng4 & ZHANG Li1,2 1 Numerical Simulation Sichuan Higher school Key Laboratory,Neijiang normal university,Neijiang 641112,china 2 College of Mathematics and information science,Neijiang normal university,Neijiang 641112,china 3 College of science,Beijing university of Civil engineering and Architecture,Beijing 100044,china 4 State Key Laboratory of Explosion science and Technology,Beijing Institute of Technology,Beijing 100081,china 1. Numerical Simulation Sichuan Higher school Key Laboratory Neijiang Normal University Neijiang 641112 China2. College of Mathematics and Information Science Neijiang Normal University Neijiang 641112 China3. College of Science Beijing University of Civil Engineering and Architecture Beijing 100044 China4. State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China

Level Set interface treatment method is introduced into Euler method,which is employed for interface treatment method for multi-materials. Combined with the ghost fluid method,the moving interface is tracked. Fifth-order WENO spatial discretization and third-order TVD Runge-Kutta time discretization methods are used. Shock-wave action on bubble,implosion and velocity field Shock effect bubbles; implosion and velocity field are simulated by means of LS-MMIC3D programmed by C++. Nu-merical results show that the Level Set interface treatment method is effective and feasible for multi-material interface treatment in comparison with the WENO method.

关键词： Euler method Level Set method shock-wave action on bubble implosion numerical simulation

Synchronization of Digital Chaos in Secure Communication Systems

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Journal of university of science and Technology Beijing 2001年第4期8卷 299-305页

作者： Geng Zhao, Deling Zheng, ShaojunHuang 1)College of Electric science and Technology Beijing. Beijing 100070, china 2)information engineering school, university of science and Technology Beijing. Beijing 100083, china Coll Elect Sci & Technol Beijing Beijing 100070 Peoples R China Univ Sci & Technol Beijing Informat Engn Sch Beijing 100083 Peoples R China

The theories of synchronization based on secure communications using digital chaos are presented. A new synchronous method-cycles-interval Pulse drive is developed and realized. Experimental results show it is available, and in order to reduce synchronous noise, a method using model references solves the ratio of signal power to noise power, so the secure communication system can be realized.

关键词： digital chaotic synchronization cycles-interval pulses drive synchronous noise model reference

Performance Modeling and Approximate Analysis of Multiserver Multiqueue Systems with Poisson and Self-similar Arrivals

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Journal of university of science and Technology Beijing 2001年第2期8卷 145-151页

作者： Zhiguang Shan, Chuang Lin, Yang Yang, Yan Wang (information engineering school, university of science and Technology Beijing, Beijing 100083, china) (Department of Computer science and Technology, Tsinghua university, Beijing 100084, china) Univ Sci & Technol Beijing Informat Engn Sch Beijing 100083 Peoples R China Tsinghua Univ Dept Comp Sci & Technol Beijing 100084 Peoples R China

The problem of state space explosion is still ran outstanding challenge in Markovian performance analysis for multiserver multiqueue (MSMQ) systems. The system behavior of a MSMQ system is described using stochastic high-level Petri net (SHLPN) models, and an approximate performance analysis technique is proposed based on decomposition and refinement methods as well as iteration technique. A real MSMQ system, Web-server cluster, is investigated. The performance of an integrated scheme of request dispatching and scheduling is analyzed with both Poisson and self-similar request arrivals. The study shows that the approximate analysis technique significantly reduces the complexity of the model solution and is also efficient for accuracy of numerical results.

关键词： multiserver multiqueue (MSMQ) system Web-server cluster performance analysis stochastic high-level Petri net (SHLPN) request dispatching request scheduling

First photometric study of the eclipsing binary PS Persei

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Research in Astronomy and Astrophysics 2011年第2期11卷 191-197页

作者： Jin-Zhao Yuan Physics and information engineering Institute,Shanxi normal university,Linfen 041004,china Physics and information engineering Institute Shanxi Normal University Linfen 041004 China

CCD photometric observations of the eclipsing binary PS Persei （PS Per） were obtained on two consecutive days in *** 2003 version of the WilsonDevinney code was used to analyze the first complete light curves in the V and R *** is found that PS Per is a short-period Algol-type binary with the less massive component completely filling its inner critical Roche *** mass ratio of q=0.518 and the orbital inclination of i=89.86° are *** addition,based on all available times of primary light minima,including two new ones,the orbital period has been improved.

关键词： stars: binaries: close -- stars: binaries: eclipsing -- stars: individual:PS Per

D(β)-vertex-distinguishing total coloring of graphs

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science china Mathematics 2006年第10期49卷 1430-1440页

作者： ZHANG Zhongfu,LI Jingwen,CHEN Xiang’en,YAO Bing, WANG Wenjie & QIU Pengxiang Institute of Applied Mathematic, Lanzhou Jiaotong university, Lanzhou 730070, china College of Mathematics and information science, Northwest normal university, Lanzhou 730070, china College of information and Electrical engineering, Lanzhou Jiaotong university, Lanzhou 730070, china Institute of Applied Mathematic Lanzhou Jiaotong University Lanzhou 730070 China College of Mathematics information science Northwest Normal University Lanzhou 730070 China College of information Electrical engineering Lanzhou Jiaotong University Lanzhou 730070 China

A new concept of the D(β)-vertex-distinguishing total coloring of graphs, i.e., the proper total coloring such that any two vertices whose distance is not larger than β have different color sets, where the color set of a vertex is the set composed of all colors of the vertex and the edges incident to it, is proposed in this paper. The D(2)-vertex-distinguishing total colorings of some special graphs are discussed, meanwhile, a conjecture and an open problem are presented.

关键词： graph, total coloring, D(β)-vertex-distinguishing total coloring, D(β)-vertexdistinguishing total chromatic number.

Calculation of triaxial superdeformation in ^(174)Hf

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science china(Physics,Mechanics & Astronomy) 2007年第5期50卷 553-557页

作者： YU ShaoYing1,2,4, LI XiaoWei2, SHEN CaiWan1,5 & CHEN YongShou3,4 1 school of science, Huzhou Teachers College, Huzhou 313000, china 2 College of Mathematics, Physics and information engineering, zhejiang normal university, jinhua 321000, china 3 china Institute of Atomic Energy, Beijing 102413, china 4 Institute of Theoretical Physics, Chinese Academy of sciences, Beijing 100080, china 5 Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000, china 1. school of science Huzhou Teachers College Huzhou 313000 China 2. College of Mathematics Physics and Information Engineering Zhejiang Normal University Jinhua 321000 China 4. Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100080 China 5. Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China 3. china Institute of Atomic Energy Beijing 102413 China

A two-dimensional Total Routhian Surface (TRS) calculation with the fixed hexa- decapole deformation ε4 = 0.03 was carried out for several configurations of 174Hf. Results indicate that the shell corrections have an important contribution to the formation of triaxial superdeformation in 174Hf and some possible configuration assignments are made to the 4 TSD bands experimentally found in 174Hf.

关键词： Total Routhian Surface (TRS), triaxial superdeformation, configuration