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

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 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 China tsinghua National Laboratory for information Science and technology Tsinghua University Beijing China research institute of information technology (RIIT) Tsinghua University Beijing 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

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Fault-Tolerant Design Techniques in A CMP Architecture

Fault-Tolerant Design Techniques in A CMP Architecture

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The 1st Chinese Conference on Trusted Computing and information Security

作者： YAO Wen-bin, WANG Dong-sheng Department of Computer Science and technology, tsinghua university. beijing 100084. China research institute of information technology. tsinghua university. beijing 100084. China

＜正＞ Single-chip multiprocessor （CMP） combined with the fault-tolerant （FT） techniques offers an ideal architecture to achieve high availability on the basis of sustaining high computing performance. FT design of a single-chip multiprocessor is described, including the techniques from hardware redundancy to software support and firmware strategy. The design aims at masking the influences of errors and automatically correcting the system states.

关键词： computer architecture fault-tolerant design single-chip multiprocessor

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Performance of Dynamic CoMP Cell Selection in 3GPP LTE System Level Simulation

Performance of Dynamic CoMP Cell Selection in 3GPP LTE Syste...

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2011 IEEE 3rd International Conference on Communication Software and Networks(ICCSN 2011)

作者： Yuan Gao Yi Li Wireless and Mobile Communication technology R&D Center research institute of information technology tsinghua university beijing China HongYi YU ShiHai Gao information Science and technology institute Zhengzhou China

With the rapid progress of 3GPP LTE/LTE-A’s standardization,research about coordinate multi point reception/transmission（CoMP）is very ***, topics about CoMP were freezed in around 2009 by 3GPP,so further research and performance analysis about key techniques in CoMP is very *** this paper,we studied the dynamic cell selection method which is presented in some proposals[1],and a performance analysis in system level is performed using our LTE system level simulator.A better algorithm of Dynamic coordinated multi-point Cell Selection is studied and suggested according to the simulation result.

关键词： dynamic cell selection LTE system level

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Hidden Markovian Chain Based Occurrence Time Prediction for GSM-R Down Fault

Hidden Markovian Chain Based Occurrence Time Prediction for ...

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2011 Chinese Control and Decision Conference（CCDC）

作者： Ming Chang is with Department of Automation,tsinghua university,beijing,P.R.China Yindong Ji,Wei Dong are with research institute of information technology,tsinghua university,beijing,P.R.China Zengke Zhang is with Department of Automation,tsinghua university,beijing,P.R.China

GSM for Railways （GSM-R） is a wireless mobile network used for train-ground *** is one of the main faults in the routine of train *** is a procedure inherently composed of several degradation levels,which was formulated as a Hidden Markovian Chain （HMC）.In the framework of HMC,a scheme based on viterbi algorithm and absorption probability was proposed to predict occurrence time of GSM-R down *** to its static version,there was a correction mechanism based on current GSM-R quality,which modified the prediction *** effectiveness of the scheme was testified by simulations,revealing that it possesses more accuracy than its static version and the defiection is restrained in a rational level.

关键词： Fault Prediction Hidden Markovian Chain Rayleigh Distribution Viterbi Algorithm Stochastic Discrete Event Systems

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H∞ Filtering for a Class of Networked Systems with Randomly Occurring Quantizations

H∞ Filtering for a Class of Networked Systems with Randomly...

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第三十届中国控制会议

作者： HE Xiao~1,WANG Zidong~(2,3),JI Yindong~1,ZHOU Donghua~2 1.research institute of information technology,tsinghua university,beijing 100084,P.R.China 2.Department of Automation,tsinghua university,beijing 100084,P.R.China 3.Department of information Systems and Computing,Brunei university,Uxbridge UB8 3PH,United Kingdom

In this paper,the H filtering problem is investigated for a class of discrete-time networked systems with random- ly occurring quantizations(ROQs).Logarithmic quantizers with different quantization laws are considered and a Bernoulli distributed stochastic sequence is utilized to determine which quantizer is used at a certain time *** converting the quantization effects into sector-bounded parameter uncertainties,a sufficient condition ensuring the existence of the desirable filters is proposed by using the Lyapunov function approach,and the parameters of the desired filters can further be obtained.A numerical example is employed to illustrate the applicability of the proposed technique.

关键词： H∞ Filtering Networked Systems(NSs) Randomly Occurring Quantizations(ROQs)

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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, China.) 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—1304 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—36 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

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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) information Engineering School University of Science and Technology Beijing 100083 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

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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,China 2 Department of Computer Science and technology,tsinghua university,beijing 100084,China 3 Network research Center,tsinghua university,beijing 100084,China tsinghua National Laboratory for information Science and technology Tsinghua University Beijing China Department of Computer Science and technology Tsinghua University Beijing China Network research Center Tsinghua University Beijing 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

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Kinetics study on the dissolution of UO_2 particles by microwave and conventional heating in 4 mol/L nitric acid

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Science China Chemistry 2008年第7期51卷 700-704页

作者： ZHAO YunFeng & CHEN Jing institute of Nuclear and New Energy technology, tsinghua university, beijing 102201, China institute of Nuclear and New Energy technology Tsinghua University Beijing China

The dissolution of UO2 particles in 4 mol·L-1 nitric acid medium at temperatures of 90-110℃ by mi- crowave heating and conventional heating has been investigated, respectively. It is found that the dissolution ratios of UO2 particles by microwave heating were 10%-40% higher than that by conven- tional heating. Kinetics research shows that the dissolution of UO2 particles in 4 mol·L-1 nitric acid is controlled by the diffusion control model for microwave heating and by the surface reaction control model for conventional heating. The diffusion control model for the dissolution of UO2 particles by mi- crowave heating could be explained by the diffuseness on the surface of UO2 particles.

关键词： uranium dioxide nitric acid dissolution microwave heating

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Application of intelligent control theory in AC servo system

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International Journal of Minerals,Metallurgy and Materials 1997年第3期11卷 43-45页

作者： WANG Zhiliang XIE Lun IJ Chongjian (information Engineering School, university of Science and technology beijing, beijing 100083, China) (Automation research institute of Metallurgical Industry, beijing 100071, China) Univ of Science and technology Beijing Beijing China

An AC servo system based on neuron control theory is presented. Experimental results show that the neuralcontrol mode doesn't need the Precise model of the system, therefore, it has many advantages, such as simple designand high response performance. The simulation research of the AC servo system which is non-linear, *** on neuro-fuzzy controller is done. The results of the simulation show that the performances of the system areconsiderably improved and it is one of the novel pathways to realize intelligent control of servo system.

关键词： servo system fuzzy control neural networks neuro-fuzzy networks

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