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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 {3. of Automation, tsinghua university, Beijing {2., China 2.{3. National Laboratory for Information Science and Technology, tsinghua university, Beijing {2., China 3.Research Institute of Information Technology (RIIT), tsinghua university, Beijing {2., 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

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A low frequency piezoelectric power harvester using a spiral-shaped bimorph

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Science China(Physics,Mechanics & Astronomy) 2006年第6期49卷 649-659页

作者： HU Yuantai1,2.HU Hongping2.& YANG Jiashi3.1. Institute of Mechanics and Sensing Technology,Central South university,Changsha 410083.China 2. department of Mechanics,Huazhong university of Science and Technology,Wuhan 43.074,China 3. department of Engineering Mechanics,university of Nebraska,Lincoln,NE 68588-052.,USA 1. Institute of Mechanics and Sensing Technology Central South University Changsha 410083 China 2. department of Mechanics Huazhong University of Science and Technology Wuhan 430074 China 3. department of Engineering Mechanics University of Nebraska Lincoln NE 68588-0526 USA

We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources. A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size. It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

关键词： spiral-shaped bimorph,piezoelectric harvester,power density.

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Fusion tracking in color and infrared images using joint sparse representation

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Science China(Information Sciences) 2012年第3期55卷 590-599页

作者： LIU HuaPing1,2.3.& SUN FuChun1,2.3.1department of Computer Science and Technology,{3., Beijing {2., China 2.tate Key Laboratory of Intelligent Technology and Systems, Beijing {2., China 3.7} National Laboratory for Information Science and Technology, Beijing {2., China 1. department of Computer Science and Technology Tsinghua University Beijing 100084 China2. State Key Laboratory of Intelligent Technology and Systems Beijing 100084 China3. Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China

Currently sparse signal reconstruction gains considerable interest and is applied in many fields. In this paper, a similarity induced by joint sparse representation is designed to construct the likelihood function of particle filter tracker so that the color visual spectrum and thermal spectrum images can be fused for object tracking. The proposed fusion scheme performs joint sparse representation calculation on both modalities and the resultant tracking results are fused using min operation on the sparse representation coefficients. In addition, a co-learning approach is proposed to update the reference templates of both modality and enhance the tracking robustness. The proposed fusion scheme outperforms state-of-the-art approaches, and its effectiveness is verified using OTCBVS database.

关键词： joint sparse representation fusion tracking color image infrared image

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SrGa_2._4∶Ce blue TFEL in new structure

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Chinese Science Bulletin 1998年第7期43卷 603-605页

作者： XU Chunxiang+1, LOU Zhidong+2. XU Zheng+3.and XU Xurong+3.. National Laboratory of Molecular and Biomolecular Electronics, Southeast university, Nanjing 2.0096, China 2. department of Applied Physics, Tianjin university, Tianjin 3.003., China 3. Institu National Laboratory of Molecular and Biomolecular Electronics Southeast University Nanjina China department of Applied Physics Tianjin University Tianjin China Institute of Photoelectronic Technology Northern Jiaotong University Beijing China

SrGa-2.-4∶Ce blue TFEL device with a novel structure was prepared by electron beam evaporation. The dielectric constant of insulator layer in this structure is far less than that in the conventional structure, so the hot-electrons can be accelerated in SiO-2.layers. The stable TFEL with good chromaticity was achieved and the basic characteristics were investigated.

关键词： SrGa-2.-4∶Ce bule TFEL low dielectric constant insulator layer.

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Determination of tectonic background for sedimentary basin from sandstone geochemistry

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Chinese Science Bulletin 1998年第14期43卷 1191-1196页

作者： SHAO Lei 1, K. Stattegger 2.and LI Wenhou 3.1. Laboratory of Marine Geology, Tongji university, Shanghai 2.0092. China 2. Geological and Paleontological Institute, university of Kiel, 2.118 Kiel, Germany 3. {2. of Geology, Northwest Unive Laboratory of Marine Geology Tongji University Shanghai China Geological and Paleontological Institute University of Kiel Kiel Germany department of Geology Northwest University Xi’an China

The chemical composition of sedimentary rocks is mainly controlled by source rocks. Through examining chemical composition of terrigenous rocks, the tectonic evolution of a sedimentary basin can be modeled. The Turpan Basin belongs to a continental sedimentary basin and its source rocks are derived from the upper continental crust.

关键词： sedimentary rock geochemistry basin analysis Turpan Basin.

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Truncation error calculation based on Richardson extrapolation for variable-step collaborative simulation

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Science China(Information Sciences) 2011年第6期54卷 1238-1250页

作者： ZHANG HeMing 1 , LIANG SiLu 2., SONG ShiJi 1 & WANG HongWei 3.1 department of Automation, TNList, tsinghua university, Beijing {2., China 2.Computer and Information Management Center, tsinghua university Beijing {2., China 3.Engineering Design Centre, Engineering department, Cambridge university, Cambridge CB2.1PZ, UK 1. department of Automation TNList Tsinghua University Beijing 100084 China2. Computer and Information Management Center Tsinghua University Beijing 100084 China3. Engineering Design Centre Engineering Department Cambridge University Cambridge CB2 1PZ UK

Collaborative simulation is an effective approach to performing simulation analysis for complex systems by integrating models developed for different engineering disciplines. Collaborative simulation issues include the modeling of coupled multidisciplinary systems, and the simulation running time integration of these models that are solved parallelly. Estimation of the local truncation error of coupling models is the key to solve multidisciplinary collaborative simulation problem, which is actually used to restrict the simulation step. This paper presents a variable-step method based on Richardson extrapolation for calculating the local truncation error to solve collaborative simulation problem of multidisciplinary coupling models. Formulas for estimating the local truncation error are derived through theoretical analysis by using integration methods and interpolation technologies, respectively. The simulation experiments are illustrated to validate the accuracy and efficiency of proposed collaborative simulation algorithm in comparison with the usual combinative algorithm.

关键词： multidisciplinary systems collaborative simulation variable-step algorithm error estimation

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Archean relic body at lower crust in Sulu area:Evidence from magnetic data

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Chinese Science Bulletin 2003年第6期48卷 589-593页

作者： WU Qifan1,2. LU Fengxiang3. LIU Qingsheng3. ZHENG Jianping3. WANG Maoji2.& WU Wenli4 1. department of Engineering Physics,{3., Beijing {2., China 2. Aero Geophysical Survey & Remote Sensing Center, Beijing 100083. China 3. China {3. of Geosciences, Wuhan 43.074, China 4. Institute of Geophysical & Geochemical Exploration, Langfang 065000, China Aero Geophysical Survey & Remote Sensing Center Beijing 100083 China China university of Geosciences Wuhan 430074 China Institute of Geophysical & Geochemical Exploration Langfang 065000 China department of Engineering Physics Tsinghua University Beijing 100084 China

After the new 1︰1000000 aero magnetic data were processed and the three-dimensional inversion work was carried out, a vast high magnetic body northwestward was discovered. The magnetic body is located at the depth of about 2. km on the west side of Tanlu fault and at about 2. km on the east side of Tanlu fault beneath the Sulu area. There is a difference of vertical distance of 3.5 km in depth between both sides. We think that the magnetic body is an Archean metamorphic plate and belongs to the North China block. The discovery of the magnetic body is significant for us to reconstruct the structure model of the Sulu orogenic belt, delineate the suture of collision between the North China block and the Yangtze block, and estimate the depth of slipping surface when the eastside of Tanlu fault moved northward.

关键词：苏鲁地区地壳下层太古代残余体地球物理调查区域性磁场三维反演苏鲁造山带郯鲁断裂带大别-苏鲁超高压变质带

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Luminescence of Eu^(2.) in Strontium Aluminum Oxide System with Long Decay Property

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Chinese Chemical Letters 1998年第4期9卷 401-402页

作者： Yong QIU and Hai Tao SUN(department of chemistry,{2., Beijing {3.) Tsing Hua Univ Dept Chem Beijing 100084 Peoples R China

A long decay luminescent powder based upon the strontium aluminum oxide system with Eu2. as the activator was produced. It was found that the variation of the molar ratio of Al to Sr leads to a change in emission colo... 详细信息

关键词： luminescence of Eu^(2.) strontium aluminum oxide emission

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Rank of loop, constraint degree of path, coupling degree of graph and their application

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Progress in Natural Science:Materials International 2005年第2期15卷 79-85页

作者： YANG Tingli1*, LUO Yufeng2. ZHANG Ce3.and YAO Fanghua1(1. SINOPIC Jinling Petrochemical Corp., Nanjing 2.003., China 2. {3. of Mechanical Engineering, Nanchang university, Nanchang 3.002., China 3. {3. of Mechanical Engineering, Tianjin university, Tianjin 3.0072. China) SINOPIC Jinling Petrochemical Corp. Nanjing 210037 China. department of Mechanical Engineering Nanchang University Nanchang 330029 China. department of Mechanical Engineering Tiánjin University Tianjin 300072 China

Some new concepts (rank of a loop, degree of freedom of a graph, path unit and ordered path arrangement, constraint degree of path, coupling degree of a graph, basic graph, etc.), formulas, and algorithms, are proposed in this paper. Based on these concepts, a new systematic theory and practical method for the design of topological structure, kinematics and dynamics of mechanical systems is established. Some conjectures and problems needed to be researched are also put forward. The concepts, formulae and algorithms presented in this paper will find wide potential applications.

关键词： rank of loop degree of freedom of graph constraint degree of path coupling degree of graph

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SIMULATION　CALCULATION　FOR　CHEMICAL　SPECIATION　OF　LEAD　BY　FEEDBACK　NEURAL　NETWORK

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Chinese Chemical Letters 1996年第3期7卷 265-266页

作者： Hua MO Bo DENG(department of chemistry,{2., Beijing, {3..) TSING HUA UNIV DEPT CHEMBEIJING 100084PEOPLES R CHINA

The chemical speciations of Ph2. in the aqueous solution can becalculated using a Feedback Neural Network. The effects of CO3.2.), random errorand temperature on the simulation results were discussed. The results show... 详细信息

关键词： LEAD OF SPECIATION FEEDBACK CALCULATION BY

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