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Communication network designing:Transmission capacity,cost and scalability

Science china(Information sciences) 2012年第11期55卷 2454-2465页

作者： zhang guoqiang1,2,3 & zhang guoqing1 1institute of computing technology,chinese academy of sciences,beijing 100190,china 2School of Computer Science and technology,Nanjing Normal University,Nanjing 210046,china 3Provincial Key Laboratory for Computer Information Processing technology,Soochow University,Suzhou 215000,china institute of computing technology Chinese Academy of Sciences Beijing China School of Computer Science and technology Nanjing Normal University Nanjing China Provincial Key Laboratory for Computer Information Processing technology Soochow University Suzhou China

Despite the growing number of works centering around the traffic dynamics on complex networks,these researches still have some common shortcomings,e.g.,too simple traffic flow model and lack of considerations for the designing cost and scalability *** paper builds on a more realistic traffic flow model,and offers a holistic view on the network designing *** addition to the extensively studied transmission capacity,this paper takes designing cost and scalability as two other designing objectives,and presents a quantitative study of how different designing choices independently and collectively influence these objectives by the introduction of a cartesian coordinate *** is shown that different kinds of network topologies display different shapes of achievable solution spaces and exhibit different abilities to achieve cost-effective and scalable *** particular,we find the philosophy underlying empirical network designing and engineering today fails to meet the cost-effective and scalable designing requirements,and propose a cost-effective and scalable designing scheme for BA-like networks,i.e.,the efficient routing combined with effective betweenness based link bandwidth *** addition,when designing a thoroughly new network from the beginning,we find that ER network is a good candidate to achieve cost-effective and scalable designing in most settings.

关键词： cost-effective communication network designing network transmission efficiency network topology traffic dynamics next generation network scalable network designing

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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 institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing China Graduate School of chinese academy of sciences Beijing 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

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Identifying heavy hitters in high-speed network monitoring

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Science china(Information sciences) 2010年第3期53卷 659-676页

作者： zhang Yu1, FANG BinXing1,2 & zhang YongZheng2 1Research Center of Computer Network and Information Security technology, Harbin institute of technology, Harbin 150001, china 2Research Center of Information Security, institute of computing technology, chinese academy of sciences, beijing 100190, china Research Center of Computer Network and Information Security technology Harbin Institute of Technology Harbin China Research Center of Information Security Institute of Computing Technology Chinese Academy of Sciences Beijing China

Identifying heavy hitters in a network traffic stream is important for a variety of network applications ranging from traffic engineering to anomaly detection such as detection of denial-of-service attacks. Existing methods generally examine newly arriving items in the stream, perform a small number of operations using a small amount of memory, and still provide guarantees on the identifying accuracy. In high-speed network monitoring, the update speed per item is extremely critical. However, so far as we know, there are no identifying algorithms which can provide constant update time (O(1)) in a weighted data stream. In this paper, we present an algorithm named Weighted Lossy Counting (WLC) which is able to identify heavy hitters in a high-speed weighted data stream with constant update time. WLC employs a novel efficient partially ordered data structure which is able to provide a fast per-item update speed while keeping the memory cost relatively low. We compare WLC with state-of-the-art algorithms for finding heavy hitters in real traffic traces. The experimental results show that WLC performs well in accuracy (recall, precision and average relative error) as other algorithms; moreover it has a much higher update speed at the cost of relatively larger memory space used. A theoretical worst-case memory bound of WLC is also derived in this paper; however, experiments with long real traffic traces show that WLC requires much less space than the theoretical bound in practice.

关键词： network traffic monitoring heavy hitter weighted data streams

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P2P traffic optimization

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Science china(Information sciences) 2012年第7期55卷 1475-1492页

作者： zhang guoqiang 1,2 ,TANG MingDong 3 ,CHENG SuQi 2,4 ,zhang guoqing 2 ,SONG HaiBin 5 ,CAO JiGuang 6 & YANG Jing 7 1 School of Computer Science and technology,Nanjing Normal University,Nanjing 210046,china 2 institute of computing technology,chinese academy of sciences,beijing 100190,china 3 School of Computer Science and Engineering,Hunan University of Science and technology,Xiangtan 411201,china 4 Graduate University of chinese academy of sciences,beijing 100190,china 5 Nanjing R&D Center,Huawei Technologies,Nanjing 210012,china 6 china academy of Telecommunication Research of MIIT,beijing 100191,china 7 china Mobile Research institute,beijing 100053,china School of Computer Science and technology Nanjing Normal University Nanjing China institute of computing technology Chinese Academy of Sciences Beijing China School of Computer Science and Engineering Hunan University of Science and Technology Xiangtan China Graduate University of chinese academy of sciences Beijing China Nanjing R&D Center Huawei Technologies Nanjing China china academy of Telecommunication Research of MIIT Beijing China china Mobile Research institute Beijing China

Peer-to-peer (P2P) based content distribution systems have emerged as the main form for content distribution on the Internet,which can greatly reduce the distribution cost of content providers and improve the overall system ***,the mismatch between the overlay and underlay networks causes large volume of redundant traffic,which intensifies the tension between P2P content providers and ***,how to efficiently use network resources to reduce the traffic burden on the ISPs is crucial for the sustainable development of P2P *** paper surveys the state-of-art P2P traffic optimization technologies from three perspectives:P2P cache,locality-awareness and data *** details,comparison between these technologies and their applicabilities are presented,followed by a discussion of the issues that remain to be addressed and the direction of future content distribution research.

关键词： P2P traffic localization P2P traffic optimization P2P cache locality-awareness network coding content-centric network

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Analysis of moment invariants under general linear transformation

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Science china(Information sciences) 2010年第7期53卷 1305-1311页

作者： DIAO LuHong1, LI Hua2, zhang Sen1 & LIU Lei1 1College of Applied sciences, beijing University of technology, beijing 100124, china 2National Center of Intelligent computing, institute of computing technology, chinese academy of Science, beijing 100080, china College of Applied sciences Beijing University of Technology Beijing China National Center of Intelligent computing Institute of Computing Technology Chinese Academy of Science Beijing China

This paper presents the necessary and sufficient condition of moment invariants under general linear transformation. Based on this condition, arbitrary order and dimensional moment invariant sets can be constructed. D... 详细信息

关键词： moment invariants independence linear transformation

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Multiparty simultaneous quantum identity authentication with secret sharing

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Science china(Physics,Mechanics & Astronomy) 2008年第3期51卷 321-327页

作者： YANG YuGuang1,2,WEN QiaoYan3 & zhang Xing4,5 1 College of Computer Science and technology,beijing University of technology,beijing 100022,china 2 State Key Laboratory of Information Security (Graduate University of the chinese academy of sciences),beijing 100049,china 3 School of Science,beijing University of Posts and Telecommunications,beijing 100876,china 4 institute of Electronic technology,Information Engineering University,Zhengzhou 450004,china 5 Trusted computing Laboratory,beijing University of technology,beijing 100022,china College of Computer Science and technology Beijing University of Technology Beijing China State Key Laboratory of Information Security (Graduate University of the chinese academy of sciences) Beijing China School of Science Beijing University of Posts and Telecommunications Beijing China institute of Electronic technology Information Engineering University Zhengzhou China Trusted computing Laboratory Beijing University of Technology Beijing China

Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented. All the users can be authenticated by a trusted third party (TTP) simultaneously. In the first protocol,the TTP shares a random key K with all the users using quantum secret sharing. The ith share acts as the authentication key of the ith user. When it is necessary to perform MSQIA,the TTP generates a random number R secretly and sends a sequence of single photons encoded with K and R to all the users. According to his share,each user performs the corresponding unitary operations on the single photon sequence sequentially. At last,the TTP can judge whether the impersonator exists. The sec-ond protocol is a modified version with a circular structure. The two protocols can be efficiently used for MSQIA in a network. They are feasible with current technol-ogy.

关键词： quantum identity authentication secret sharing quantum cryptography

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RADIAL BASIS FUNCTION INTERPOLATION IN SOBOLEV SPACES AND ITS APPLICATIONS

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Journal of Computational Mathematics 2007年第2期25卷 201-210页

作者： Manping zhang (School of Mathematical sciences,Fudan University,Shanghai 200433,china institute of Computational Mathematics,chinese academy of sciences,beijing 100080,china School of Mathematical sciences Fudan University Shanghai 200433

In this paper we study the method of interpolation by radial basis functions and give some error estimates in Sobolev space H^k（Ω）（k 〉 1）. With a special kind of radial basis function, we construct a basis in H^k（Ω） and derive a meshless method for solving elliptic partial differential equations. We also propose a method for computing the global data density.

关键词： Sobolev space Radial basis function Global data density Meshless method

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Numerical simulation of Richtmyer-Meshkov instability

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Science china Mathematics 2004年第Z1期47卷 234-244页

作者： FU Dexun, MA Yanwen, zhang Linbo & TIAN BaolinState Key Laboratory of Nonlinear Mechanics, institute of Mechanics, chinese academy of sciences, beijing 100080, china State Key Laboratory of Scientific and Engineering computing, institute of Computational Mathematics, chinese academy of sciences, beijing 100080, china State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing China State Key Laboratory of Scientific and Engineering computing Institute of Computational Mathematics Chinese Academy of Sciences Beijing China

The compressible Navier-Stokes equations discretized with a fourth order accurate compact finite difference scheme with group velocity control are used to simulate the Richtmyer-Meshkov (R-M) instability problem produced by cylindrical shock-cylindrical material interface with shock Mach number Ms=1.2 and density ratio 1:20 (interior density/outer density). Effect of shock refraction, reflection, interaction of the reflected shock with the material interface, and effect of initial perturbation modes on R-M instability are investigated numerically. It is noted that the shock refraction is a main physical mechanism of the initial phase changing of the material surface. The multiple interactions of the reflected shock from the origin with the interface and the R-M instability near the material interface are the reason for formation of the spike-bubble structures. Different viscosities lead to different spike-bubble structure characteristics. The vortex pairing phenomenon is found in the initial double mode simulation. The mode interaction is the main factor of small structures production near the interface.

关键词： R-M instability, direct numerical simulation, shock-interface interaction.

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Observation constraints of the hard X-ray modulation telescope HXMT

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 31-35页

作者： LU Yu1,2,zhang WenZhao3,QU JinLu1,SONG LiMing1,GAO Jian3,zhang HongMei4 & OU Ge4 1 Key Laboratory of Particle Astrophysics,institute of High Energy Physics,chinese academy of sciences,beijing 100049,china 2 Graduate University of chinese academy of sciences,beijing 100049,china 3 Department of Astronomy,beijing Normal University,beijing 100875,china 4 computing Center,institute of High Energy Physics,chinese academy of sciences,beijing 100049,china Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Department of Astronomy Beijing Normal University Beijing China computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing China

The hard X-ray modulation telescope HXMT is a low orbit X-ray space telescope whose main science goals are to accomplish a hard X-ray all sky survey and to study timing and spectral characteristics of X-ray *** has three kinds of science instruments:the high energy X-ray detector(HE),the medium energy X-ray detector(ME) and the low energy X-ray detector(LE).The observation schedule of HXMT is a key to achieving the science goal of HXMT,and the analysis of the observation constraints is one of the first tasks in making the observation *** paper analyzes how the observation constraints influence the sky visibility and the visible time distribution of X-ray sources and discusses the schedule strategy with regard to the observation constraints.

关键词： HXMT observation constraints sky visibility

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The properties of halo structure for ^(17)B

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Science china(Physics,Mechanics & Astronomy) 2008年第7期51卷 781-787页

作者： HU ZhengGuo1, WANG Meng1, XU HuShan1, SUN ZhiYu1, WANG JianSong1, XIAO guoqing1, ZHAN WenLong1, XIAO ZhiGang1, MAO RuiShi1,2, LI Chen1, zhang XueYing1,2, zhang HongBin1, ZHAO TieCheng1, XU ZhiGuo1, WANG Yue1,2, CHEN RuoFu1,2, HUANG TianHeng1,2, FU Fen1,2, GAO Qi1,2, HAN JianLong1,2, zhang XueHeng1,2, ZHENG Chuan1,2, YU YuHong1,2 & GUO ZhongYan1 1 institute of Modern Physics, chinese academy of sciences, Lanzhou 730000, china 2 Graduate University of the chinese academy of sciences, beijing 100049, china institute of Modern Physics Chinese Academy of Sciences Lanzhou China Graduate University of the chinese academy of sciences Beijing China

The total reaction cross section (1724±93 mb) of 17B at the energy of 43.7 A MeV on C target has been measured by using the transmission method at the Radioactive Ion Beam Line in Lanzhou (RIBLL). Assuming 17B consists of a core 15B plus two halo neutrons,the total cross section of 17B on C target was calculated with the zero-range Glauber model,where double Gaussian density distributions and Gaussian plus HO density distributions were used. It can fit the experimental data very well. The characteristic of halo structure for 17B was found with a large diffusion of the neutrons density distribution.

关键词： total cross section density distribution Glauber model the characteristic of halo structure

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