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A formal method to real-time protocol interoperability testing

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science in China(Series F) 2008年第11期51卷 1723-1744页

作者： WANG ZhiLiang1,3.YIN Xia2,3.& JING ChuanMing2,3.1 Network Research Center,tsinghua University,beijing 100084,China 2 Department of Computer science and {3.,tsinghua University,beijing 100084,China 3.tsinghua national laboratory for information science and {3.(TNList) ,beijing 100084,China 1. Network Research Center Tsinghua University Beijing 100084 China 3. tsinghua national laboratory for {3. science and technology (TNList) Beijing 100084 China 2. Department of Computer science and technology Tsinghua University Beijing 100084 China

Interoperability testing is an important technique to ensure the quality of implementations of network communication protocol. In the next generation Internet protocol, real-time applications should be supported effectively. However, time constraints were not considered in the related studies of protocol interoperability testing, so existing interoperability testing methods are difficult to be applied in real-time protocol interoperability testing. In this paper, a formal method to real-time protocol interoperability testing is proposed. Firstly, a formal model CMpTIOA （communicating multi-port timed input output automata） is defined to specify the system under test （SUT） in real-time protocol interoperability testing; based on this model, timed interoperability relation is then defined. In order to check this relation, a test generation method is presented to generate a parameterized test behavior tree from SUT model; a mechanism of executability pre-determination is also integrated in the test generation method to alleviate state space explosion problem to some extent. The proposed theory and method are then applied in interoperability testing of IPv6 neighbor discovery protocol to show the feasibility of this method.

关键词： protocol testing interoperability testing real-time testing test generation timed input output automata(TIOA)

RRM:An incentive reputation model for promoting good behaviors in distributed systems

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science in China(Series F) 2008年第11期51卷 1871-1882页

作者： ZHANG Hong1,2,DUAN HaiXin1,3.& LIU Wu1,3.1 tsinghua national laboratory for {3. science and technology,tsinghua University,beijing 100084,China 2 Department of Computer science and technology,tsinghua University,beijing 100084,China 3.Network Research Center,tsinghua University,beijing 100084,China 1. tsinghua national laboratory for {3. science and technology Tsinghua University Beijing 100084 China 2. Department of Computer science and technology Tsinghua University Beijing 100084 China 3. Network Research Center Tsinghua University Beijing 100084 China

Reputation systems represent soft security mechanisms that complement traditional information security mechanisms. They are now widely used in online e-commerce markets and communities in order to stimulate good behaviors as well as to restrain adverse behaviors. This paper analyzes the limitations of the conversational reputation models and proposes an incentive reputation model called the resilient reputation model （RRM） for the distributed reputation systems. The objective of this reputation model is not only to encourage the users to provide good services and, therefore, to maximize the probability of good transaction outcomes, but also to punish those adverse users who are trying to manipulate the application systems. The simulation results indicate that the proposed reputation model （RRM） could effectively resist against the common adverse behaviors, while protecting the profits of sincere users from being blemished by those adversaries.

关键词： reputation model distributed system trust soft security

Theoretical research progress in new-generation Internet architecture

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science in China(Series F) 2008年第11期51卷 1634-1660页

作者： WU JianPing1,2,3.LIU Ying2,3.& WU Qian2,3.1 Department of Computer science,tsinghua University,beijing 100084,China 2 Network Research Center,tsinghua University,beijing 100084,China 3.tsinghua national laboratory for information science and technology(TNList) ,beijing 100084,China 1. Department of Computer science Tsinghua University Beijing 100084 China 2. Network Research Center Tsinghua University Beijing 100084 China 3. tsinghua national laboratory for {3. science and technology (TNList) Beijing 100084 China

Internet has become the most important information infrastructure supporting modern socio-economic development, social progress and technological Innovation. Invented 3. years ago, today Internet is facing increasingly severe technical challenges. This paper introduces the progress of the major international newgeneration Internet research plans; analyzes its basic characteristics and the principal contradictions during the development; detsiledly introduces the research carried out by 973.Project ＂Research of Future Internet Architecture＂ on the key scientific issues of new-generation Internet architecture and its latest research results; and looks to the future of the research-focus faced with the new situations of the basic research of new-generation Internet architecture as well as the new demands of innovative applications on Internet architecture.

关键词： new-generation Internet network architecture multi-dimension scalability

A TTCN-3.based protocol testing system and its extension

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science in China(Series F) 2008年第11期51卷 1703-1722页

作者： YIN Xia1,3.WANG ZhiLiang2,3.JING ChuanMing1,3.& SHI XinGang2,3.1 Department of Computer science and technology,tsinghua University,{3.,China 2 Network Research Center,tsinghua University,{3.,China 3.tsinghua national laboratory for information science and technology(TNList) ,{3.,China 1. Department of Computer science and technology Tsinghua University Beijing 100084 China 3. ]tsinghua national laboratory for {3. science and technology (TNList) Beijing 100084 China 2. Network Research Center Tsinghua University Beijing 100084 China

The protocol testing technology used in the next generation Internet should satisfy some new challenges and requirements. This paper focuses on the test suite description and test implementation techniques. TTCN-3.is chosen as the test suite description language and extended in both syntax and semantics to satisfy the requirements of protocol robustness testing. PITSv3. a protocol integrated testing system based on TTCN-3. is developed, and the extensions for robustness testing are implemented. Finally, two practical test applications are presented.

关键词： protocol testing TTCN-3 PITSv3 robustness testing

Building a next generation Internet with source address validation architecture

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science in China(Series F) 2008年第11期51卷 1681-1691页

作者： WU JianPing1,3.REN Gang1,3.& LI Xing2,3.1 Department of Computer science,tsinghua University,beijing 100084,China 2 Department of Electronic Engineering,tsinghua University,beijing 100084,China 3.tsinghua national laboratory for information science and technology(TNList) ,beijing 100084,China Department of Computer science Tsinghua University Beijing 100084 China Department of Electronic Engineering Tsinghua University Beijing 100084 China tsinghua national laboratory for {3. science and technology (TNList) Beijing 100084 China

The IP packet forwarding of current Internet is mainly destination based. In the forwarding process, the source IP address is not checked in most *** causes serious security, management and accounting problems. Based on the drastically increased IPv6 address space, a ＂source address validation architecture＂（SAVA） is proposed in this paper, which can guarantee that every packet received and forwarded holds an authenticated source IP address. The design goals of the architecture are lightweight, loose coupling, ＂multi-fence support＂ and incremental deployment. This paper discusses the design and implementation for the architecture, including inter-AS, intra-AS and local subnet. The performance and scalability of SAVA are described. This architecture is deployed into the CNGI-CERNET2 infrastructure a large-scale native IPv6 backbone network of the China Next Generation Internet project. We believe that the SAVA will help the transition to a new, more secure and dependable Internet.

关键词： IP source address validation network architecture network security

Influence of magnetic current on the ground state entanglement in an isotropic transverse XY chain

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Progress in Natural science:Materials International 2007年第10期17卷 1147-1151页

作者： Liu Dan1,2 , Zhang Yong3.and Long Guilu1,2(1. Key laboratory for Atomic and Molecular Nanosciences, and Department of Physics, tsinghua University, {3., China 2. Center of Quantum information science and technology, tsinghua national laboratory for information science and technology, {3., China 3. Institute of Physics, School of sciences, beijing University of Posts and Telecommunications, beijing 100876, China) Key laboratory for Atomic and Molecular Nanosciences and Department of Physics Tsinghua University Beijing 100084 China Center of Quantum information science and technology Tsinghua National Laboratory for information Science and Technology Beijing 100084 China Institute of Physics School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 China

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ>3. namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.

关键词： Heisenberg-XY chain magnetic-current phase transition.

Fuzzy tolerance quotient spaces and fuzzy subsets

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science China(information sciences) 2010年第4期53卷 704-714页

作者： ZHANG Ling1 & ZHANG Bo2,3.4* 1Computer science & technology College, Anhui University, Anhui 23.03., China 2State Key laboratory of Intelligent technology and Systems, beijing 100084, China 3.5} national laboratory of information science & technology, beijing 100084, China 4information science & technology College, Computer science & technology Department, tsinghua University, beijing 100084, China 1. Computer science & technology College Anhui University Anhui 230039 China2. State Key Laboratory of Intelligent Technology and Systems Beijing 100084 China3. Tsinghua National Laboratory of Information Science & Technology Beijing 100084 China4. Information Science & Technology College Computer Science & Technology Department Tsinghua University Beijing 100084 China

The structure and characteristic of fuzzy subsets are discussed by using the concepts of granulation and hierarchy in quotient space theory. First, the equivalence relation based quotient space theory is extended to the fuzzy tolerance relation. Second, the isomorphism and its discriminant of fuzzy tolerance relations are discussed. Finally, by using the fuzzy tolerance relation to define the fuzzy subset, its properties are addressed. The main results are given below: (1) several equivalent statements of fuzzy tolerance relations; (2) the definition of isomorphism of fuzzy tolerance relations; (3. the isomorphic discriminant of fuzzy tolerance relations; (4) the definition and properties of fuzzy subsets based on the fuzzy tolerance relations; and (5) the necessary and sufficient condition of the isomorphism of fuzzy subsets. These results will help us further comprehend the concepts of fuzzy tolerance relations and fuzzy subsets.

关键词： Fuzzy tolerance relation quotient space isomorphism fuzzy subset

Real-time reliability prediction for dynamic systems with both deteriorating and unreliable components

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science in China(Series F) 2009年第11期52卷 2234-2246页

作者： XU ZhengGuo1,2, JI YinDong2,3.& ZHOU DongHua1,2? 1 Department of Automation, tsinghua University, beijing 100084, China 2 tsinghua {3. laboratory for information science and technology, tsinghua University, beijing 100084, China 3.Research Institute of information technology (RIIT), tsinghua University, beijing 100084, China Department of Automation Tsinghua University Beijing 100084 China tsinghua national laboratory for {3. science and technology Tsinghua University Beijing 100084 China Research Institute of information technology (RIIT) Tsinghua University Beijing 100084 China

As an important technology for predictive maintenance, failure prognosis has attracted more and more attentions in recent years. Real-time reliability prediction is one effective solution to failure prognosis. Considering a dynamic system that is composed of normal, deteriorating and unreliable components, this paper proposes an integrated approach to perform real-time reliability prediction for such a class of systems. For a deteriorating component, the degradation is modeled by a time-varying fault process which is a linear or approximately linear function of time. The behavior of an unreliable component is described by a random variable which has two possible values corresponding to the operating and malfunction conditions of this component. The whole proposed approach contains three algorithms. A modified interacting multiple model particle filter is adopted to estimate the dynamic system＇s state variables and the unmeasurable time-varying fault. An exponential smoothing algorithm named the Holt＇s method is used to predict the fault process. In the end, the system＇s reliability is predicted in real time by use of the Monte Carlo strategy. The proposed approach can effectively predict the impending failure of a dynamic system, which is verified by computer simulations based on a three-vessel water tank system.

关键词： reliability failure prognostics dynamic systems fault prediction particle filtering interacting multiple model exponential smoothing,predictive maintenance

An introduction to tsinghua Cloud

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science China(information sciences) 2010年第7期53卷 1481-1486页

作者： ZHENG WeiMin1,2 1Department of Computer science and technology, tsinghua University, {3., China 2tsinghua national laboratory for information science and technology, {3., China 1. Department of Computer science and technology Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China

Cloud computing has become a trend that draws attention from both academia and industry all over the world. This paper unveils details of tsinghua Cloud, a comprehensive solution for cloud computing developed by Tsing... 详细信息

关键词： cloud computing distributed file system virtual computing environment data sharing