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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 Information Science and Technology,tsinghua university,beijing 100084,{3. 2 Department of Computer Science and Technology,tsinghua university,beijing 100084,{3. 3.network research Center,tsinghua university,beijing 100084,{3. 1. tsinghua National Laboratory for Information 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

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,{3.,china 2 Department of Computer Science and Technology,tsinghua university,{3.,china 3.tsinghua National Laboratory for Information Science and Technology(TNList) ,{3.,china 1. network research Center Tsinghua University Beijing 100084 China 3. tsinghua National Laboratory for Information 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)

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,beijing 100084,china 2 {3. 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 and Technology Tsinghua University Beijing 100084 China 3. ]tsinghua National Laboratory for Information 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

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 {3. National 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 Information 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

GHG emission reductions and costs to achieve Kyoto target

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Journal of Environmental Sciences 2003年第4期15卷 541-547页

作者： CHEN Wen\|ying (Energy, Environment and Economy research Institute, tsinghua university, beijing 100084, {3..) Energy Environment and Economy Research Institute Tsinghua University 北京 100084

Emission projection and marginal abatement cost curves(MACs) are the central components of any assessment of future carbon market, such as CDM (clean development mechanism) potentials, carbon quota price etc. However, they are products of very complex, dynamic systems driven by forces like population growth, economic development, resource endowments, technology progress and so on. The modeling approaches for emission projection and MACs evaluation were summarized, and some major models and their results were compared. Accordingly, reduction and cost requirements to achieve the Kyoto target were estimated. It is concluded that Annex I Parties' total reduction requirements range from 503.13.4 MtC with USA participation and decrease significantly to 140—612 MtC after USA's withdrawal. Total costs vary from 21—77 BUSD with USA and from 5—3. BUSD without USA if only domestic reduction actions are taken. The costs would sharply reduce while considering the three flexible mechanisms defined in the Kyoto Protocol with domestic actions' share in the all mitigation strategies drops to only 0—16%.

关键词： Kyoto Protocol emission reduction abatement cost flexible mechanisms

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 Information 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

A Middleware-based Distributed Management Framework for Next-generation network

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计算机工程 2002年第S1期28卷 62-66页

作者： ZHANG JinxiangWU JianpingWANG Jilong(network research Center of tsinghua university,{3.,china) network research Center of tsinghua university Beijing 100084China

As the basis for next-generation application middleware, distributed computing technique is increasingly used in the network management to fulfill the integration of diverse management systems. Furthermore Web technology is widely used in interaction friendly with user. This article puts forward a MNMI (Middleware-based network Management Integration) framework in the domain of the management of IPv6 test bed-NSFCNET (National Natural Science Foundation of china network). The framework uses a logically-layers method from user interface to managers and pseudo-agent, which uses distributed management and groups managed objects to retrieve, and thus it has assured the performance of network management by providing multiple object quick access.

关键词： network managementCORBAWebFramework

Reduced analysis and confirmatory research on co-adaptability theoretical solution to conflicting events in construction engineering projects

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Science china(Technological Sciences) 2010年第2期53卷 480-485页

作者： HOU XueLiang1 , LU Mei2 & WANG Kai3.1 School of Business Administration, North china Electric Power university, beijing 102206, china 2 Department of Construction Management, tsinghua university, beijing 100084, china 3.College of Management, beijing Jiaotong university, beijing 100084, china 1. School of Business Administration North China Electric Power University Beijing 102206 China2. Department of Construction Management Tsinghua University Beijing 100084 China3. College of Management Beijing Jiaotong University Beijing 100084 China

The co-adaptability theoretical solution to conflicting events in construction engineering projects has three problems. First, the transformation of constraint conditions of theoretical solution is very difficult in practical engineering applications; second, some coefficients are difficult to be determined; third, there are overfull circular arithmetic operations involved in it. To resolve these problems, a new method to reduce the theoretical solution complications is proposed. By analyzing the operating mechanism of theoretical solution model, redundancies in the theoretical solution can be eliminated, and the ISM mapping with the co-adaptability solution can be set up. Based on this approach, a procedure to solve practical conflicting events in construction projects is established by replacing characteristic variables with mathematic variables. The research results show that the procedure can replace the co-adaptability theoretical solution effectively and solve practical conflicting events in construction projects.

关键词： construction project conflict theoretical solution reduced analysis ISM confirmatory research

Extremal eigenvalues of measure differential equations with fixed variation

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Science china Mathematics 2010年第10期53卷 2573-2588页

作者： ZHANG MeiRong 1,2 1 Department of Mathematical Sciences,tsinghua university,beijing 100084,china 2 Zhou Pei-Yuan Center for Applied Mathematics,tsinghua university,beijing 100084,china 1. Department of Mathematical Sciences Tsinghua University Beijing 100084 China2. Zhou Pei-Yuan Center for Applied Mathematics Tsinghua University Beijing 100084 China

In this paper we will study eigenvalues of measure differential equations which are motivated by physical problems when physical quantities are not absolutely *** taking Neumann eigenvalues of measure differential equations as an example,we will show how the extremal problems can be completely solved by exploiting the continuity results of eigenvalues in weak* topology of measures and the Lagrange multiplier rule for nonsmooth *** results can give another explanation for extremal eigenvalues of SturmLiouville operators with integrable potentials.

关键词： measure differential equation eigenvalue extremal value weak* topology Frechét derivative sub-differential