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A parallel and robust object tracking approach synthesizing adaptive Bayesian learning and improved incremental subspace learning

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Frontiers of Computer Science 2019年第5期13卷 1116-1135页

作者： kang LI Fazhi HE Haiping YU Xiao chen State Key Laboratory of Software Engineering School of Computer Science Wuhan University Wuhan 430072 China School of Computer Science and Information Engineering Hubei University Wuhan 430062 China

This paper presents a novel tracking algorithm which integrates two complementary trackers. Firstly, an improved Bayesian tracker(B-tracker) with adaptive learning rate is presented. The classification score of B-tracker reflects tracking reliability, and a low score usually results from large appearance change. Therefore, if the score is low, we decrease the learning rate to update the classifier fast so that B-tracker can adapt to the variation and vice versa. In this way, B-tracker is more suitable than its traditional version to solve appearance change problem. Secondly, we present an improved incremental subspace learning method tracker(Stracker). We propose to calculate projected coordinates using maximum posterior probability, which results in a more accurate reconstruction error than traditional subspace learning tracker. Instead of updating at every time, we present a stopstrategy to deal with occlusion problem. Finally, we present an integrated framework(BAST), in which the pair of trackers run in parallel and return two candidate target states separately. For each candidate state, we define a tracking reliability metrics to measure whether the candidate state is reliable or not, and the reliable candidate state will be chosen as the target state at the end of each frame. Experimental results on challenging sequences show that the proposed approach is very robust and effective in comparison to the state-of-the-art trackers.

关键词： object tracking Bayesian learning subspace learning particle filter principal component analysis

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Numerical Simulation of Peen Forming

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上海交通大学学报 2004年第z2期38卷 73-78页

作者： kang Xiaoming Ma Zeen Gu Lin chen ming School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030 China Department of Aircraft Manufacturing Engineering Northwestern Polytechnical UniversityXi''an710072China School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030 China School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030 China

Peen forming is the most important process for the manufacturing of integral wing skin panels. In order to determine peening parameters, an equivalent deformation theory was proposed in which peening parameters are transformed into equivalent nodal forces. In this study, a linear elastic shell finite element method is adopted. Other related problems such as wing skin panel modeling and peening scheme analysis were also outlined. The method has been applied to manufacturing panels of a certain Chinese aircraft and was proved to be effective in reducing peening experimental tests and improving products quality.

关键词： peen forming wing skin panel equivalent deformation theory numerical simulation

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中国有色金属学会会刊：英文版 2001年第6期11卷 843-846页

作者： Yan, HG chen, ZH kang, ZT chen, G Hunag, PY Hunan Univ Sch Mat Sci & Engn Changsha 410082 Peoples R China Cent S Univ Dept Mat Sci & Engn Changsha 410083 Peoples R China

The phase formation regularities in nanometer powders of ternary alloys prepared by gas evaporation process with induction current as the heating source were investigated. Al-Cu-Mn and Al-Cu-Cr were chosen as the samples in this study. The experimental results show that the necessary conditions for forming ternary compound phases in a ternary alloy nanometer powder are that they must be able to form in a conventional bulk alloy. To obtain a ternary compound phase in nanometer powders, composition of the master alloy must be in a certain range. Changing the composition of the master alloy and evaporation temperature can control the kinds of the phases and their relative amount in the alloy nanometer powders. In present study, AlMn, Al8Mn5 and AlCu2Mn phases formed in as-prepared nanometer powders of Al-Cu-Mn alloy, and the highest relative amount of AlCu2Mn phase is about 99%. In nanometer powders of Al-Cu-Cr alloy,Cu9Al4, Al2Cu3, AlCr2 and Al13Cr2 phases formed without any ternary compound phase.

关键词： nanometer powder gas evaporation alloy powder

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Modeling and Experimental Analysis of Roughness Effect on Ultrasonic Nondestructive Evaluation of Micro-crack

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Chinese Journal of Mechanical Engineering 2021年第6期34卷 126-137页

作者： Zhe Wang Zhichao Fan Xuedong chen Yihua kang Jingwei cheng Wei chen National Safety Engineering Technology Research Center for Pressure Vessels and Pipeline Hefei General Machinery Research Institute Co.LtdHefei230031China State Key Lab of Digital Manufacturing Equipment&Technology Huazhong University of Science and TechnologyWuhan430074China

A high-precision evaluation of ultrasonic detection sensitivity for a micro-crack can be restricted by a corroded rough surface when the surface microtopography is of the same order of magnitude as the crack *** this study,a back-surface micro-crack is considered as a research target.A roughness-modified ultrasonic testing model for micro-cracks is established based on a multi-Gaussian beam model and the principle of phase-screen *** echo signals of micro-cracks and noises corresponding to different rough front surfaces and rough back surfaces are obtained based on a reference reflector signal acquired from a two-dimensional simulation *** compari-son between the analytical and numerical models shows that the responses of micro-cracks under the effects of dif-ferent corroded rough surfaces can be accurately *** numerical and analytical results show that the echo signal amplitude of the micro-crack decreases significantly with an increase in roughness,whereas the noise ampli-tude slightly ***,the effect of the rough front surface on the echo signal of the micro-crack is greater than that of the rough back *** the root-mean-square(RMS)height of the surface microtopography is less than 15μm,the two rough surfaces have less influence on the echo signals detected by a focused transducer with a frequency of 5 MHz and diameter of 6 mm.A method for predicting and evaluating the detection accuracy of micro-cracks under different rough surfaces is proposed by combining the theoretical model and a finite element ***,a series of rough surface samples containing different micro-cracks are fabricated to experimentally validate the evaluation method.

关键词： Surface roughness Micro-crack Ultrasonic testing model Detection accuracy Evaluation method

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Polyoxometalates for continuous power generation by atmospheric humidity

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Nano Research 2024年第3期17卷 1875-1885页

作者： Tuo Ji Weilin chen Zhenhui kang Liming Zhang Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education Northeast Normal UniversityChangchun 130024China Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices DepartmentSoochow UniversitySuzhou 215123China Macao Institute of Materials Science and Engineering Macao University of Science and TechnologyTaipaMacao 999078China Institute of Functional State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

Atmospheric humidity is a sustainable low-value energy widely existing in natural environment,which is a promising candidate to solve the noncontinuous and low efficiency of low-value energy power *** the mono-substituted Dawson-type polyoxometalates are constructed to be highly dispersed organic ammonium-polyoxoanion clusters and are assembled into thin films power generators with micropores,working in atmospheric *** optimal polyoxometalates generator with the thickness of 7.2μm and the area of 0.36 cm^(2) produces a voltage of 0.68 V and a current density of 19.5μA·cm^(-2) under simulated natural environment,and works continuously and stably under almost all-natural environments(humidity 10%–90%).The highly dispersed polyoxometalate nanoclusters can form microporous in polyoxometalate films to effectively absorb atmospheric humidity and spontaneously form distribution gradient of water,which is the structural basis of power *** continuous power generation may be maintained by the effective adsorption and utilization of H_(2)O,the huge electrostatic field of organic ammonium-polyoxoanion clusters,and the reasonably designed polyoxometalates containing inorganic small ions with high *** is the first humidity generator designed with polyoxometalates,which may provide a new research direction for polyoxometalates in sustainable utilization of low-value energy.

关键词： atmospheric humidity continuous power generations nanomaterials polyoxoanions polyoxometalates

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Event co-reference resolution via a multi-loss neural network without using argument information

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Science China(Information Sciences) 2019年第11期62卷 31-39页

作者： Xinyu ZUO Yubo chen kang LIU Jun ZHAO Institute of Automation Chinese Academy of Sciences University of Chinese Academy of Sciences

Event co-reference resolution is an important task in natural language processing, and nearly all the existing approaches for this task rely on event argument information. However, these methods tend to suffer from error propagation from event argument extraction. Additionally, not every event mention contains all arguments of an event, and the argument information may confuse the model where events contain arguments to detect an event co-reference in real text. Furthermore, the context information of an event is useful to infer the co-reference between events. Thus, to reduce the errors propagated from event argument extraction and use context information effectively, we propose a multi-loss neural network model that does not require any argument information relating to the within-document event co-reference resolution task; furthermore, it achieves a significantly better performance than the state-of-the-art methods.

关键词： event co-reference resolution neural network information extraction multi-loss function event extraction

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Lessons Learned from Optimizing the Sunway Storage System for Higher Application I/O Performance

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Journal of Computer Science & Technology 2020年第1期35卷 47-60页

作者： Qi chen kang chen Zuo-Ning chen Fellow CCF Wei Xue Xu Ji Bin Yang Department of Computer Science and Technology Beijing National Research Center for Information Science and Technology(BNRist)Tsinghua UniversityBeijing 100084China Chinese Academy of Engineering Beijing 100088China National Supercomputing Center in Wuxi Wuxi 214100China School of Software Shandong UniversityJinan 250101China

It is hard for applications to make full utilization of the peak bandwidth of the storage system in highperformance computers because of I/O interferences,storage resource misallocations and complex long I/O *** performed several studies to bridge this gap in the Sunway storage system,which serves the supercomputer Sunway *** locate these issues and connections between them,an end-to-end performance monitoring and diagnosis tool was developed to understand I/O behaviors of applications and the *** the help of the tool,we were about to find out the root causes of such performance barriers at the I/O forwarding layer and the parallel file system *** application-aware I/O forwarding allocation framework was used to address the I/O interferences and resource misallocations at the I/O forwarding layer.A performance-aware data placement mechanism was proposed to mitigate the impact of I/O interferences and performance variations of storage devices in the ***,applications obtained much better I/O *** the process,we also proposed a lightweight storage stack to shorten the I/O path of applications with N-N I/O *** paper summarizes these studies and presents the lessons learned from the process.

关键词： high performance computing I/O interference parallel file system performance optimization resource misallocation

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Methods to determine stress profile in ALT based on theoretical life models

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Chinese Journal of Aeronautics 2015年第3期28卷 729-736页

作者： chen Yunxia Jing Hailong Liao Xun kang Rui School of Reliability and Systems Engineering Beihang University

Abstract With the recent products being more reliable, engineers cannot obtain enough failure or degradation information through the design period and even the product lifetime, therefore, accel erated life test （ALT） ihas become the most popular way to quantify the life characteristics of prod ucts. Test design is the most essential topic, such as testing duration, stress profile, data inference, etc. In this paper, a method and procedure based on theoretical life models is proposed to determine the accelerated stress profile. Firstly, the method for theoretical life calculation is put forward based on the main failure mechanism analysis and the theoretical life models. Secondly, the method is pro vided to determine the accelerated stress profile, including the method to determine the accelerated stress types and the stress range on the basis of the main failure mechanism analysis, the method to determine the acceleration factor and the accelerated stress level based on life quantitative calcula tion models, and the collaborative analysis method of the accelerated test time while taking the mul tiple failure mechanisms into consideration. Lastly, the actuator is taken as an example to describe the procedure of the method and the engineering applicability and the validity are verified.

关键词： Acceleration factor Accelerated stress profileALT Failure mechanisms Main failure mechanismanalysis Theoretical life models

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Self-centering characteristics of a petal-shaped capsule robot

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Science China(Technological Sciences) 2019年第4期62卷 619-627页

作者： ZHANG YongShun chen Jun ZHANG Yu MENG kang Key Laboratory for Precision & Non-traditional Machining Technology of Ministry of Education Dalian University of Technology School of Computer Science and Technology Faculty of Electronic Information and Electrical Engineering Dalian University of Technology

Based on the multiple wedge effects, a petal-shaped capsule robot(PCR) is proposed, and the self-centering phenomenon of the PCR is discovered. For investigating the self-centering characteristics, an innovative concept of the instantaneous fluid membrane(FM) thickness, along with the dynamic FM thickness, is proposed; thus a dynamic FM thickness model and a hydrodynamic pressure(HP) model are derived when the PCR axis deviates from the pipe axis under the effect of gravity. A kinematics equation during suspending process in the vertical direction and a swimming kinematics equation in axial direction are derived respectively. Four capsule robots with different eccentricities of the tiles were manufactured and tested, the theoretical and experimental results show that the HP gradient is a fundamental reason for the self-centering phenomenon. The PCR with the self-centering ability can directly avoid the contact with the bottom of the gastrointestinal(GI) tract, achieving the excellent obstacle surmounting ability in the GI complex environment with the less twisted impact on the GI tract, which has a promising application prospect in the GI diagnosis.

关键词： petal-shaped capsule robot self-centering characteristics multiple wedge effects complete suspension phenomenon

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A compositional method to model dependent failure behavior based on PoF models

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Chinese Journal of Aeronautics 2017年第5期30卷 1729-1739页

作者： Zhiguo ZENG Yunxia chen Enrico ZIO Rui kang EDF Foundation Chair on Systems Science and Energetic Challenge CentraleSupelec Universite Paris-Saclay Grande Voie des Vignes 92290 Chatenay-Malabry France School of Reliability and Systems Engineering Beihang University Beijing 100083 China Energy Department Politecnieo di Milano Italy

In this paper, a new method is developed to model dependent failure behavior among failure mechanisms. Unlike the existing methods, the developed method models the root cause of the dependency explicitly, so that a deterministic model, rather than a probabilistic one, can be established. Three steps comprise the developed method. First, physics-of-failure（PoF） models are utilized to model each failure mechanism. Then, interactions among failure mechanisms are modeled as a combination of three basic relations, competition, superposition and coupling. This is the reason why the method is referred to as ＂compositional method＂. Finally, the PoF models and the interaction model are combined to develop a deterministic model of the dependent failure behavior. As a demonstration, the method is applied on an actual spool and the developed failure behavior model is validated by a wear test. The result demonstrates that the compositional method is an effective way to model dependent failure behavior.

关键词： Degradation Dependent failures Multiple dependent competing failure processes Reliability modeling Shock

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