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International Conference on Advances in P2P systems (AP2PS)

作者： Gang Zhou Jianjun Yu National Digital Switching System Engineering and Technological Research and Development Center China State Key Laboratory of Software Development Environment Beihang University China Computer Network Information Center Chinese Academy and Sciences China

We present the design of pService system for P2P Web services discovery supporting similarity search with its locality-preserving feature based on modified Skip Graph. In pService, the most important property (e.g. service name) of a service is viewed as the indexing key of a peer node. The other properties are extracted as multiattributes which would be mapped into one-dimensional indices using HSFC (Hilbert Space Filling Curve), and assigned to membership vector of the peer node. These two features help to support similarity search in two aspects: peer nodes with similar indexing keys would be distributed neighborly, peer nodes with similar indices will connect to each other through routing table. Our evaluation showed that the pService performs considerable Web services discovery efficiency.

关键词： Peer to peer computing Web services Indexing Routing Hilbert space Filling Search engines Data structures Switching systems Design engineering

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Tuning and monitoring of quantum dot growth by an in situ cantilever

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Physical Review B 2009年第4期79卷 045401-045401页

作者： Yan Wang Jörg Weissmüller Huiling Duan Department of Mechanics and Aerospace Engineering and State Key Laboratory for Turbulence and Complex System College of Engineering Peking University Beijing 100871 People’s Republic of China Institut für Nanotechnologie Forschungszentrum Karlsruhe Karlsruhe 76021 Germany Technische Physik Universität des Saarlandes Saarbrücken 66041 Germany

Self-organization of quantum dots (QDs) on an in situ cantilever setup is investigated using a continuum approach. In this QD growth system, the cantilever has two functions. The first function is as a substrate of QD growth and the second is to tune and detect the morphologies of QDs. We calculate the free energy, consisting of elastic energy, surface energy, island-substrate interaction energy, wetting-layer-substrate interaction energy, and island-island interaction energy, and we analyze their contributions to the total free energy in the QD growth system. Then, we calculate the critical quantity of the deposited material, above which the QD growth system will transfer from the planar film state to the island array state, and the curvature of the cantilever during QD growth. The curvatures of the cantilever are functions of island coverage, island size, facet orientation of island, thickness of the wetting layer, and thickness of the cantilever. It is shown that the in situ cantilever setup can not only tune the morphologies of QDs by properly choosing the thickness of the cantilever but can also monitor the QD growth state with a high sensitivity.

关键词： crystal growth free energy island structure nanostructured materials self-assembly semiconductor quantum dots surface energy surface morphology

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Steady state speed distribution analysis for a combined cellular automaton traffic model

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Chinese Physics B 2008年第8期17卷 2850-2858页

作者：王俊峰陈桂生刘进 College of Computer Science Sichuan University Institute of Electronic System Engineering State Key Laboratory of Software Engineering Wuhan University

Cellular Automaton （CA） based traffic flow models have been extensively studied due to their effectiveness and simplicity in recent years. This paper develops a discrete time Markov chain （DTMC） analytical framework for a Nagel-Schreckenberg and Fukui Ishibashi combined CA model （W^2H traffic flow model） from microscopic point of view to capture the macroscopic steady state speed distributions. The inter-vehicle spacing Maxkov chain and the steady state speed Markov chain are proved to be irreducible and ergodic. The theoretical speed probability distributions depending on the traffic density and stochastic delay probability are in good accordance with numerical simulations. The derived fundamental diagram of the average speed from theoretical speed distributions is equivalent to the results in the previous work.

关键词： cellular automaton traffic flow model speed distribution discrete time Markov chain

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Model Checking Needham-Schroeder Security Protocol Based on Temporal Logic of Knowledge

Model Checking Needham-Schroeder Security Protocol Based on ...

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International Conference on Networks Security, Wireless Communications and Trusted Computing, NSWCTC

作者： Xiangyu Luo Yan Chen Ming Gu Lijun Wu School of Software Key Laboratory of Security for Information System of Ministry of Education Tsinghua University Beijing China Department of Computer Science Guilin University of Electronic Technology Guilin China School of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu China

ISBN: (纸本)9781424442232

Formal verification approaches can guarantee the correctness of security protocols. In this paper we take the well-known Needham-Schroeder public-key authentication protocol as an example, to show how we can apply the symbolic model checker for multiagent systems MCTK, which is developed by us, to the verification of security protocols. One temporal epistemic property is checked successfully both in the original version and the Lowe's revised version of the Needham-Schroeder protocol. The experimental result shows that our method is an effective way to the verification of security protocol.

关键词： Logic Computer security Cryptographic protocols Communication system security Information security Electronic mail Authentication Multiagent systems Cryptography Computer networks

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DFTT4CWS: A Testing Tool for Composite Web Services Based on Data-Flow

DFTT4CWS: A Testing Tool for Composite Web Services Based on...

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Web Information systems and Applications Conference (WISA)

作者： Jun Hou Lei Xu School of Computer Science and Engineering South-East University Nanjing China China Telecom Jiangsu Hongxin System Integration Company Limited Nanjing China State Key Laboratory for Novel Software Technology Department of Computer Science and Technology Nanjing University Nanjing China

For large and complex composite Web services which are composed by BPEL and a set of WSDL and XSD documents, we urgently need the aid of the tools in designing and selecting test cases. However, most of mature testing tools which generate test data with the information of WSDL are used for single service while the research for composition remains in the realm of theory. So we apply the theory of data-flow testing and try to develop a testing tool for Web services composition which can automatically detects harmful data-flow anomalies and generate test paths according to all kinds of data flow coverage criteria.

关键词： Web services Automatic testing Application software system testing Computer science Sequential analysis Information systems Data engineering Design engineering Telecommunications

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Wave propagation in a magneto-electro- elastic plate

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Science China(Physics,Mechanics & Astronomy) 2008年第6期51卷 651-666页

作者： WEI JianPing SU XianYue State Key Laboratory for Turbulence and Complex System and Department of Mechanics and Aerospace Engineering Peking UniversityBeijing 100871China

The wave propagation in a magneto-electro-elastic plate was studied. Some new characteristics were discovered: the guided waves are classified in the forms of the Quasi-P, Quasi-SV and Quasi-SH waves and arranged by the standing wavenumber; there are many patterns for the physical property of the magneto-electro-elastic dielectric medium influencing the stress wave propagation. We proposed a self-adjoint method, by which the guided-wave restriction condition was derived. After the corresponding orthogonal sets were found, the analytic dispersion equa-tion was obtained. In the end, an example was presented. The dispersive spectrum, the group velocity curved face and the steady-state response curve of a mag-neto-electro-elastic plate were plotted. Then the wave propagations affected by the induced electric and magnetic fields were analyzed.

关键词： magneto-electro-elastic plate guided-wave restriction condition dispersive equation dispersive spectrum group velocity curved face steady-state response curve

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Numerical Simulation of Random Close Packing with Tetrahedra

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Chinese Physics Letters 2008年第5期25卷 1724-1726页

作者：李水乡赵健周璇 College of Engineering Peking University Beijing 100871 State Key Laboratory for Turbulence and Complex System Study Peking University Beijing 100871

The densest packing of tetrahedra is still an unsolved problem. Numerical simulations of random close packing of tetrahedra are carried out with a sphere assembly model and improved relaxation algorithm. The packing density and average contact number obtained for random close packing of regular tetrahedra is 0.6817 and 7.21 respectively, while the values of spheres are 0.6435 and 5.95. The simulation demonstrates that tetrahedra can be randomly packed denser than spheres. Random close packings of tetrahedra with a range of height are simulated as well. We find that the regular tetrahedron might be the optimal shape which gives the highest packing density of tetrahedra.

关键词： supernova explosion proto-neutron star shock wave

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Robust Controller Design for Networked Control systems with Nonlinear Uncertainties

Robust Controller Design for Networked Control Systems with ...

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2009 American Control Conference (ACC 2009)

作者： Junyan Yu Long Wang Mei Yu Jie Chen Yingmin Jia Intelligent Control Laboratory Center for Systems and Control College of Engineering and Key Laboratory of Machine Perception (Ministry of Education) Peking University Beijing 100871 P.R.China Department of Automation North China Electric Power University Zhuxinzhuang Dewai Beijing 102206 P.R.China Beijing Institute of Technology Key Laboratory of Complex System Intelligent Control and Decision Ministry of Education Beijing 100081 P.R.China Seventh Research Division Beihang University Beijing 100083 P.R. China

ISBN: (纸本)9781424445233

We address robust stabilization problem for networked control systems with nonlinear uncertainties and packet losses by modelling such systems as a class of uncertain switched systems. Based on theories on switched Lyapunov functions, we derive the robustly stabilizing conditions for state feedback stabilization and design packet-loss dependent controllers by solving some matrix inequalities. A numerical example and some simulations are worked out to demonstrate the effectiveness of the proposed design method.

关键词： Networked control systems robust controller design Packet loss control systems design approach Switched systems controller design State feedback Uncertainty nonlinearity

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Optimized modeling of signalized intersections coordination based on two-way bandwidth maximization

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Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University (engineering and Technology Edition) 2009年第SUPPL. 2期39卷 19-24页

作者： Ma, Nan Shao, Chun-Fu Zhao, Yi Key Laboratory of Urban Transportation Complex System Theory and Technology Ministry of Education Beijing Jiaotong University Beijing 100044 China Department of Civil and Environmental Engineering University of Nevada Reno Reno NV89557 United States

To reduce traffic delays, relieve congestion, and improve the operation of urban traffic network, a phase sequence optimization model was presented based on the idea of maximization of two-way green wave bandwidth. Under 15 difference groups of scenarios, VISSIM was used for testifying the effectiveness of the optimization model. The simulation results show that the optimized scheme reduces the intersection delay by 2%-29%, the number of stops by 14%-28% and travel time by 1%-9%, which greatly improves the operation condition of urban road network.

关键词： Bandwidth

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Analysis and improvement of ZG off-line TTP non-repudiation protocol

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Tongxin Xuebao/Journal on Communications 2009年第11 A期30卷 44-51页

作者： Liu, Dong-Mei Qing, Si-Han Li, Peng-Fei Li, Shang-Jie National Engineering Research Center for Fundamental Software Institute of Software Chinese Academy of Sciences Beijing 100080 China Engineering Research Center for Information Security Technology Institute of Software Chinese Academy of Sciences Beijing 100080 China Graduate School Chinese Academy of Sciences Beijing 100039 China National Key Laboratory of Integrated Information System Technology Chinese Academy of Sciences Beijing 100080 China

Based on the weakness of ZG off-line TTP(trusted third party) non-repudiation protocol because of using protocol deadline, the improvement of the ZG off-line TTP non-repudiation protocol was given, which eliminated the delaying resolve request attack and ensured non-repudiation and fairness. Therefore, two kinds of improvement of ZG off-line TTP non-repudiation protocol were given, which had different point of focus. Among them, the first one could eliminate delaying message attack in ZG protocol;the second one also had the property of preventing the abuse of sub-protocol besides eliminating delaying message attack. The first one is suitable for electronic payment and certified email, but the second one is suitable for digital contract signature.

关键词： Fair non-repudiation protocol Fairness Non-repudiation Timeliness

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