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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 {3. 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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Characteristics of fMRI BOLD signal and its neurophysiological mechanism

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Progress in Natural science:Materials International 2007年第6期17卷 630-638页

作者： Zhao Xiaohu1,2, Wu Yigen3.and Guo Shengli3.1. College of Life sciences, Zhejiang University, Hangzhou 3.0058, china 2. Imaging Department of Tongji Hospital of Tongji University, Shanghai 200065, china 3. College of Mathematics and Physics, Nanjing University of {3. science and technology, Nanjing 210044, china) College of Life sciences Zhejiang University Hangzhou 310058 China Imaging Department of Tongji Hospital of Tongji University Shanghai 200065 China College of Mathematics and Physics Nanjing University of Information Science and Technology Nanjing 210044 China

The functional magnetic resonance imaging (fMRI) based on blood oxygen level dependent (BOLD) contrast has emerged as one of the most potent noninvasive tools for mapping brain function and has been widely used to explore physiological, pathological changes and mental activity in the brain. Exploring the nature and property of BOLD signal has recently attracted more attentions. Despite that great progress has been made in investigation of the characteristics and neurophysiological basis, the exact nature of BOLD signal remains unclear. In this paper we discuss the characteristics of BOLD signals, the nonlinear BOLD response to external stimuli and the relation between BOLD signals and neural electrophysiological recordings. Furthermore, we develop our new opinions regarding nonlinear BOLD response and make some perspectives on future study.

关键词： functional magnetic resonance imaging blood oxygen level dependent nonlinear response neural electrophysiological activity.

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The crustal structure under Sanjiang and its dynamic implications:Revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan

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science china Earth sciences 2005年第9期48卷 1329-1336页

作者： ZHANG Zhongjie1, BAI Zhiming1, WANG Chunyong2, TENG Jiwen1, Lü Qingtian3. LI Jiliang1, LIU Yifeng1 & LIU Zhenkuan4 1. Institute of Geology and Geophysics, Chinese Academy of sciences, beijing 100029, china 2. Institute of Geophysics, china Seismological Bureau, beijing 100085, china 3. Institute of Deposition Resource, Chinese Academy of Geosciences, beijing 10003., china 4. School of Exploration and information, china University of Geosciences, beijing 100083. china Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Institute of Geophysics China Seismological Bureau Beijing China Institute of Deposition Resource Chinese Academy of Geosciences Beijing China School of Exploration and information China University of Geosciences Beijing China

The fault belts in Sanjiang mainly include Jinshajiang-Honghe fault, Lancangjiang fault and Nujiang fault (called Sanjiang faults) in western Yunnan Province, china. By interpreting the wide-angle seismic reflection/refraction profile between Zhefang and Binchuan, which crosses Tengchong and Baoshan blocks in Dianxi (western Yunnan) tectonic zone, we recon- struct the crustal structure with seismic traveltime tomography for crustal P-wave velocity and the seismic scattering image for crustal seismic reflection structure. In this paper, we firstly present the crustal structure images of P-wave velocity and seismic reflection under the wide-angle seismic profile. These results demonstrate that, the crustal velocity structure and seismic reflec- tion structure along the profile can be divided into 3.segments, and there is an obvious difference of crustal structure among the eastern, the western and the middle segment. Generally, crustal P-wave velocities in the Baoshan segment are 0.1―0.2 km/s slower and seismic reflection am- plitudes from Moho discontinuity are stronger than the other 2 segments. In the studied area, crustal thickness is about 40 km, and shows the thickening tendency from west to east along the profile. Additionally, it can be seen that there is one strong-amplitude seismic reflection event as bright points at the depths of 8―10 km, along the segment of 80―115 km of the profile (south- ward of Tengchong); and seismic reflection wave-field from Moho discontinuity varies obviously along the lateral direction. Finally, we make some discussions on the crustal thickening pattern in the Sanjiang fault belt, structural environment of earthquake development and the contact rela- tionship between the Tengchong block, Banshan block and Luxi trough.

关键词： Sanjiang area wide-angle seismic profile crustal structure.

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A Raw Signal Simulator for Bistatic SAR

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Chinese Journal of Aeronautics 2009年第4期22卷 434-443页

作者： Xia Weijie,Zhou Jianjiang College of information science and technology,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,{3. College of information science and technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

This article proposes a new efficient raw signal simulator for the bistatic synthetic aperture radar （SAR） based on 2D fast Fourier transform （FFT） to deal with cases of both ideal trajectory and trajectory deviation. It begins with analyzing the geometric configuration and the range history of the bistatic SAR in side-looking and squint modes of ideal trajectory as well as trajectory deviation. Then a detailed and mathematical study is conducted on the equivalence relation of bistatic-to-monostatic applications （BTMA） in the case of ideal trajectory and trajectory deviation. Also a set of formulas are derived for the equivalence relation between bistatic SAR and monostatic SAR on some reasonable assumptions. Therefore, the application of the simulation method based on the 2D FFT for the monostatic SAR can be extended to the case of bistatic SAR. Finally, the simulation results prove the validity of this method. By comparing the efficiency of the proposed method with that of the time domain method, it is shown that the former is a few orders of magnitude higher.

关键词： bistatic synthetic aperture radar raw signal simulation fast Fourier transform

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Sequence stratigraphy and depositional systems in the Paleogene,Liaodong Bay

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Petroleum science 2008年第2期5卷 110-118页

作者： Ji Hancheng School of Resources and information technology China University of Petroleum Beijing 102249 China

Based on drilling and seismic data, the Paleogene developed in Liaodong Bay can be divided into five third-order sequences bounded by six sequence boundaries. Through analyzing depositional systems in each sequence in detail, the Es-3.time was defined as fast rifting. During the deposition of the Es-3.member, the lake basin was continuous along the N-S direction but compartmentalized along the E-W direction by several N-S trending faults. Deposition was dominated by steep slope fans and fan deltas. The time of Es-2 and Es-1 was stable settling. The lake basin expanded substantially. The fan delta system and braided fluvial system were developed. Carbonate and clastic deposits were formed on the Liaoxi （west Liaohe） Rise. The time of Ed-3.time was again fast rifting. During this time, shale was deposited. In the time of Es-2, tectonic movement weakened. The basin was higher in the west and north, and lower in the east and south. A series of delta depositional systems were developed and smallscale slumping turbidite fans were present in semi-deep lake to deep lake. In the time of Ed-1, tectonic movement stopped. Flood plain deposition occurred. Finally the paper presents the characteristics of evolution and distribution of depositional systems both vertically and horizontally.

关键词： Liaodong Bay Paleogene sequence depositional system

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RST transforms resistant image watermarking based on centroid and sector-shaped partition

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science china(information sciences) 2012年第3期55卷 650-662页

作者： ZHAO Yao1,2*, NI RongRong1,2* & ZHU ZhenFeng1,2* 1Institute of information science, beijing Jiaotong University, beijing 100044, china 2beijing Key Laboratory of Advanced information science and Network technology, beijing 100044, china Institute of information science Beijing Jiaotong University Beijing China beijing Key Laboratory of Advanced information science and Network {3. Beijing China

A novel digital watermarking scheme featuring centroid-based sectoring is proposed in this paper. To get higher robustness against geometric attacks, such as rotation, scaling, and translation (RST), a delicate synchronization mechanism was developed and incorporated into the proposed approach. During the process of watermark embedding, the original image was partitioned into sectors based on the image centroid. Synchronization information as well as the message bits is then embedded into these sectors. With the help of the centroid-based sectoring and synchronization information, the proposed approach is capable of restoring the correct sectoring even if it has experienced severe geometric distortion. This attribute ensures the correct recovery of embedded watermarks and contributes to the robustness of the proposed scheme. A series of experiments have been conducted to verify the feasibility and effectiveness of the proposed approach. Experimental results show that the proposed scheme possesses good robustness against RST attacks and considerable robustness against other common image processing attacks.

关键词： digital watermarking geometrical transform attacks RST transforms

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Multiparty quantum secret sharing of classical and quantum messages

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Progress in Natural science:Materials International 2007年第1期17卷 26-31页

作者： CHEN Pan, DENG Fuguo and LONG Guilu ( Key Laboratory for Quantum information and Measurements, and Department of Physics, Tsinghua University, beijing 100084, china Key Laboratory of Beam {3. and Material Modification, MOE, Institute of Low Energy Nuclear Physics, and Department of Material science and Engineering, beijing Normal University, beijing 100875, china beijing Radiation center, beijing 100875, china Key Laboratory for Atomic and Molecular Nano-sciences, Tsinghua University, beijing 100084, china) Key Laboratory for Quantum information and Measurements and Department of Physics Tsinghua University Beijing 100084 China Key Laboratory of Beam technology and Material Modification MOE Institute of Low Energy Nuclear Physics and Department of Material Science and Engineering Beijing Normal University Beijing 100875 China beijing Radiation center Beijing 100875 China Key Laboratory for Atomic and Molecular Nano-sciences Tsinghua University Beijing 100084 China

A scheme for multiparty quantum secret sharing of classical and quantum messages is proposed by using entanglement swapping. This scheme can distribute not only the classical information but also the quantum informati... 详细信息

关键词： quantum secret sharing classical message quantum message EPR pair.

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Absence of State Collapse and Revival in a Superconducting Charge Qubit

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Communications in Theoretical Physics 2007年第12期48卷 1029-1032页

作者： HUO Wen-Yi~1 and LONG Gui-Lu~(1,2,3.~1 Department of Physics amd Key Laboratory for Quantum information and Measurements,Tsinghua University,beijing100084,china~2 Key Laboratory for Atomic and Molecular Nano{3.s,Tsinghua University,beijing 100084,china~3.National Laboratory for information {3. and technology,Hsinghua University,beijing 100084,china Department of Physics amd Key Laboratory for Quantum information and Measurements Tsinghua University Key Laboratory for Atomic and Molecular Nanosciences Tsinghua University National Laboratory for information science and technology Hsinghua Univers

The Hamiltonian of a superconducting charge qubit with a configuration of dc SQUID contains an interac-tion between the LC oscillator part and charge *** interaction may leads to quantum state collapse and revivalwhich degrades the charge qubits and leads to serious *** analysis shows that the existing charge qubitparameters do not lead to this phenomenon,which is very good for the superconducting charge

关键词： quantum computer superconducting charge qubit absence and revival

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Possible mechanism of the effect of convection over Asian-Australian “land bridge” on the East Asian summer monsoon onset

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science china Earth sciences 2006年第11期49卷 1223-1232页

作者： HE Jinhai1, WEN Min2, DING Yihui3.& ZHANG Renhe2 1. Jiangsu Key Laboratory of Meteorological Disaster (KLME), Nanjing Institute of Meteorology, Nanjing University of Informa- tion science and technology, Nanjing 210044, china 2. State Key Laboratory of Severe Weather (LaSW), Chinese Academy of Meteorological sciences, beijing 100081, china 3. National Climate center, Chinese Meteorological Administration, beijing 100081, china Jiangsu Key Laboratory of Meteorological Disaster (KLME) Nanjing Institute of Meteorology Nanjing University of Information Science and Technology Nanjing China State Key Laboratory of Severe Weather (LaSW) Chinese Academy of Meteorological Sciences Beijing China National Climate center Chinese Meteorological Administration Beijing China

The Asian-Australian “land bridge” is an area with the most vigorous convection in Asian monsoon region in boreal spring, where the onset and march of convection are well associated with the onset of East Asian summer monsoon. The convection occurs over Indo-china Peninsula as early as mid-April, which exerts critical impact on the evolution of monsoon circulation. Before mid-April there are primarily sensible heatings to the atmosphere over Indo-china Peninsula and Indian Peninsula, so the apparent heating ratios over them decrease with height. However, after mid-April it changes into latent heating over Indo-china Peninsula due to the onset of convection, and the apparent heating ratio increases with height in mid- and lower troposphere. The vertical distribution of heating ratio and its differences between Indo-china Peninsula and Indian Peninsula are the key factors leading to the splitting of boreal subtropical high belt over the Bay of Bengal. Such mechanism is strongly supported by the fact that the evolution of the vertical heating ratio gradient above Indo-china Peninsula leads that of 850 hPa vorticity over the Bay of Bengal. Convections over Indo-china Peninsula and its surrounding areas further increase after the splitting. Since then, there is a positive feedback lying among the convective heating, the eastward retreat of the subtropical high and the march of monsoon, which is a possible mechanism of the advance of summer monsoon and convection from Indo-china Peninsula to South china Sea.

关键词： Asian-Australian 'land bridge', tropical convection, Indo-china Peninsula, the splitting of boreal subtropical high belt, East Asian summer monsoon onset.

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“S-R”模型的国防科技信息用户情报行为研究

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图书情报工作 2011年第16期55卷 55-58页

作者：雷帅中国国防科技信息中心研究生部北京100142

针对国防科技信息用户情报行为研究问题,借助行为心理学中的"S-R"理论,在对其基本模型进行扩展的基础上构建出用户情报行为研究的扩展模型,从中挖掘出用户情报行为影响三要素,然后依据"S-R"扩展模型对国防科技信息用户情报行为进行分析... 详细信息

针对国防科技信息用户情报行为研究问题,借助行为心理学中的"S-R"理论,在对其基本模型进行扩展的基础上构建出用户情报行为研究的扩展模型,从中挖掘出用户情报行为影响三要素,然后依据"S-R"扩展模型对国防科技信息用户情报行为进行分析。在分析的基础上,提出针对国防科技信息机构应对新形势挑战的三点启示。

关键词： “S-R”模型国防科技信息用户情报行为

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