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A spatio-velocity model based semantic event detection algorithm for traffic surveillance video

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Science china(Technological Sciences) 2010年第S1期53卷 120-125页

作者： SHENG Hao 1,ZHAO HuiJie 1,HUANG Jian 2 & LI Na 1 1 school of Instrument Science and Opto-Electro Engineering,beihang university,beijing 100191,china 2.school of software,beihang university,beijing 100191,china 1. school of Instrument Science and Opto-Electro Engineering Beijing University Beijing 100191 China 2. school of software Beijing University Beijing 100191 China

Detection of vehicle events is a research hotspot in digital *** this paper,an approach is proposed to detect vehicle events with semantic analysis of traffic surveillance video using spatio-velocity statistic *** approach includes two successive phases:trajectory clustering and semantic events *** trajectory clustering,a statistic model of vehicle trajectories are presented,for which a spatio-velocity model is trained by analyzing the trajectories of moving vehicles in the *** on the trajectory,which represents both the position of the vehicle and its instantaneous velocity,a trajectory similarity measure is ***,an improved hierarchical clustering algorithm is adopted to cluster the trajectories according to different spatial and velocity *** each cluster,trajectories that are spatially close have similar velocities of motion and represent one type of activity *** the semantic events detection phase,statistic models of semantic regions in the scene are generated by estimating the probability density and velocity distributions of each type of activity ***,semantic events are detected by the proposed spatio-velocity statistic *** paper also presents experiments using real video sequence to verify the effectiveness of the proposed method.

关键词： trajectory clustering spatio-velocity statistic model event detection digital traffic

Adaptive control for autonomous rendezvous of spacecraft on elliptical orbit

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Acta Mechanica Sinica 2009年第4期25卷 539-545页

作者： Shan Lu Shijie Xu school of Astronautics, beihang university,100191 beijing, china school of Astronautics Beihang University 100191 Beijing China

A strategy for spacecraft autonomous rendezvous on an elliptical orbit in situation of no orbit information is developed. Lawden equation is used to describe relative motion of two spacecraft. Then an adaptive gain factor is introduced, and an adaptive control law for auton- omous rendezvous on the elliptical orbit is designed using Lyapunov approach. The relative motion is proved to be ultimately bounded under this control law, and the final relative position error can achieve the expected magnitude. Simulation results indicate that the adaptive control law can realize autonomous rendezvous on the elliptical orbit with relative state information only.

关键词： Autonomous rendezvous Elliptical orbit Lyapunov approach Adaptive control Gain factor

Simulation of three-dimensional nonideal MHD flow at high magnetic Reynolds number

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中国科学：技术科学英文版 2010年第1期53卷 206-212页

作者： LU HaoYu1 & Lee ChunHian2 1 school of Astronautics,beihang university,beijing 100191,china 2 National Laboratory for Computational Fluid Dynamics,beihang university,beijing 100191,china 1. school of Astronautics Beihang University Beijing 100191 China2. National Laboratory for Computational Fluid Dynamics Beihang University Beijing 100191 China

A conservative TVD scheme is adopted to solve the equations governing the three-dimensional flow of a nonideal compressible conducting fluid in a magnetic *** eight-wave equations for magnetohydrodynamics(MHD) are proved to be a non-strict hyperbolic system,therefore it is difficult to develop its *** developed a new set of equations which cannot be numerically simulated by conservative TVD scheme directly due to its non-conservative form.A conservative TVD scheme augmented with a new set of eigenvectors is proposed in the *** validate this scheme,1-D MHD shock tube,unsteady MHD Rayleigh problem and steady MHD Hartmann problem for different flow conditions are *** simulated results are in good agreement with the existing analytical *** this scheme can be used to effectively simulate high-conductivity fluids such as cosmic MHD problem and hypersonic MHD flow over a blunt body,etc.

关键词： magnetohydrodynamics(MHD) numerical simulation TVD MHD Rayleigh flow MHD Hartmann flow

Reliability-aware automatic composition approach for web services

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Science china(Information Sciences) 2012年第4期55卷 921-937页

作者： LI Mu 1,2,LI Bo 1,2 & HUAI JinPeng 1,2 1 State Key Laboratory of software Development Environment,beihang university,beijing 100191,china 2.school of Computer Science and Engineering,beihang university,beijing 100191,china 1. State Key Laboratory of software Development Environment Beihang University Beijing 100191 China2. School of Computer Science and Engineering Beihang University Beijing 100191 China

In this paper,we study the reliability-aware synthesis problem for composing available services automatically and guaranteeing that the composed result satisfies the specification,such as temporal constraints of functionality and reliability,centered on a synthesis model for mediator of web services composition (CSM).This approach focuses on handling attributes and state relations,and permitting users and services to operate over them,i.e.,read /write their data values and compare them according to a dense state *** show that the reliability-aware synthesis problem for the specification is EXPTIME-complete and we give an exponential-time algorithm (CSM-NSA) which for a given formula ψ and a synthesis model,synthesizes available services in the library satisfying ψ over the synthesis model (if they exist) or responds with "not satisfiable" (otherwise).The specification ψ is a fragment of PCTL (probabilistic computation tree logic),obtained from "ordinary" CTL (computation tree logic) by replacing the EX,AX,EU and AU operation with their quantitative counterparts X >p,X =1,U >p,and U =1,*** opposed to NSA,we provide a more effective algorithm to replace the NSA algorithm called CSM-HSA (heuristic synthesis algorithm).Though HSA is an incomplete algorithm,the answer is *** experiments show that the HSA algorithm solves the problem of reliability-aware service synthesis effectively and efficiently.

关键词： reliability web services synthesis problem synthesis model heuristic algorithm

An approach to detecting abnormal vehicle events in complex factors over highway surveillance video

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Science china(Technological Sciences) 2008年第S2期51卷 199-208页

作者： SHENG Hao1,XIONG Zhang1,WENG JingNong2 & WEI Qi1 1 College of Computer,beihang university,beijing 100191,china 2 College of software,beihang university,beijing 100191,china College of Computer Beihang University Beijing 100191 China College of software Beihang University Beijing 100191 China

The detection of abnormal vehicle events is a research hotspot in the analysis of highway surveillance *** of the complex factors,which include different conditions of weather,illumination,noise and so on,vehicle's feature extraction and abnormity detection become *** paper proposes a Fast Constrained Delaunay Triangulation(FCDT) algorithm to replace complicated segmentation algorithms for multi-feature *** on the video frames segmented by FCDT,an improved algorithm is presented to estimate background *** the estimation,a multi-feature eigenvector is generated by Principal Component Analysis(PCA) in accordance with the static and motional features extracted through locating and tracking each *** abnormity detection,adaptive detection modeling of vehicle events(ADMVE) is presented,for which a semi-supervised Mixture of Gaussian Hidden Markov Model(MGHMM) is trained with the multi-feature eigenvectors from each video *** normal model is developed by supervised mode with manual labeling,and becomes more accurate via iterated *** abnormal models are trained through the adapted Bayesian learning with unsupervised *** paper also presents experiments using real video sequence to verify the proposed method.

关键词： background estimation abnormity detection adaptive detection modeling a semi-supervised MGHMM

Adaptive neuro fuzzy inference system for classification of water quality status

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Journal of Environmental Sciences 2010年第12期22卷 1891-1896页

作者： Han Yan,Zhihong Zou,Huiwen Wang school of Economics and Management,beihang university,beijing 100191,china [a] school of Economics Management Beihang University Beijing 100191 China

An adaptive neuro fuzzy inference system was used for classifying water quality status of river. It applied several physical and inorganic chemical indicators including dissolved oxygen, chemical oxygen demand, and ammonia-nitrogen. A data set （nine weeks, total 845 observations） was collected from 100 monitoring stations in all major river basins in china and used for training and validating the model. Up to 89.59% of the data could be correctly classified using this model. Such performance was more competitive when compared with artificial neural networks. It is applicable in evaluation and classification of water quality status.

关键词： adaptive neuro fuzzy inference system artificial neural networks water quality status classification

Complexity of synthesis of composite service with correctness guarantee

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Science china(Information Sciences) 2012年第3期55卷 638-649页

作者： DENG Ting1,2 , HUAI JinPeng1,3 & WO TianYu1,3 1State Key Laboratory of software Development Environment, beihang university beijing 100191, china 2school of Mathematics and System Science, beihang university, beijing 100191, china 3school of Computer Science and Engineering, beihang university, beijing 100191, china 1. State Key Laboratory of software Development Environment Beihang University Beijing 100191 China2. School of Mathematics and System Science Beihang University Beijing 100191 China3. School of Computer Science and Engineering Beihang University Beijing 100191 China

How to compose existing web services automatically and to guarantee the correctness of the design (e.g. temporal constraints specified by temporal logic LTL, CTL or CTL*) is an important and challenging problem in web services. Most existing approaches use the process in conventional software development of design, verification, analysis and correction to guarantee the correctness of composite services, which makes the composition process both complex and time-consuming. In this paper, we focus on the synthesis problem of composite service; that is, for a given set of services and correctness constraint specified by CTL or CTL* formula, a composite service is automatically constructed which guarantees that the correctness is ensured. We prove that the synthesis problem for CTL and CTL* are complete for EXPTIME and 2EXPTIME, respectively. Moreover, for the case of synthesis failure, we discuss the problem of how to disable outputs of environment (i.e. users or services) reasonably to make synthesis successful, which are also proved complete for EXPTIME and 2EXPTIME for CTL and CTL*, respectively.

关键词： business protocol composite service synthesis environment branching temporal logic

3D building modeling,organization and application in digital city system

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中国科学：技术科学英文版 2010年第S1期53卷 134-142页

作者： YANG Xue 1,WENG JingNong 1,2,XIA YuBin 2,WU Lun 3 & SUI ZhengWei 3 1 College of software,beihang university,beijing 100191,china 2 College of Computer,beihang university,beijing 100191,china 3 Institute of Remote Sensing and GIS,Peking university,beijing 100871,china beihang Univ Coll Software Beijing 100191 Peoples R China beihang Univ Coll Comp Beijing 100191 Peoples R China Peking Univ Inst Remote Sensing & GIS Beijing 100871 Peoples R China

The real world is a three-dimensional(3D)space requiring that 3D geospatial information applications be developed in alignment with the observer’s visual and perceptive ***,3D building model data are required in a wide range of areas such as urban planning,environmental protection,real estate management and emergency *** the same time,the development of Web service[LU1]technologies allows the possibility of the widely distributed 3D geospatial data on the web.3D city building model with its related information is an important part in the construction of a digital city system,and has become a staple resource on the web *** view of the hierarchical representation of a 3D building model,an abstract of a 3D building model based on structure details is studied,and a novel representation approach named 3D transparent building hierarchical model is presented in this *** approach fully uses both the existing 3D modeling technologies and CAD constructing mapping *** the spatial relationship description,structural components inside a building can be represented and integrated as hierarchical models in a unified 3D *** addition,based on the characteristics of the 3D building model data,a service-oriented architecture and Web service technologies for 3D city building models are *** aim of the approach is that 3D city building models can be used as a kind of data resource service on the web,and can also exist independently in various different web applications.

关键词： 3D modeling 3D transparent building hierarchical models china Star web services

Large field of view computed laminography with the asymmetric rotational scanning geometry

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Science china(Technological Sciences) 2010年第8期53卷 2261-2271页

作者： FU Jian 1,2 ,JIANG BaiHong&LI Bin 1 school of Mechanical Engineering and Automation,beihang university,beijing 100191,china 2 Research Center of Digital Radiation Imaging and Biomedical Imaging,beihang university,beijing 100191,china 1. school of Mechanical Engineering and Automation Beihang University Beijing 100191 China2. Research Center of Digital Radiation Imaging and Biomedical Imaging Beihang University Beijing 100191 China

X-ray computed laminography(CL)is used in the fields of industrial inspection and medical *** can provide the internal structure three-dimensional(3D)information of a region of the objects *** is important to the clinical diagnosis and the quality control of flat objects like printed circuit boards,aircraft wings and satellite solar *** the restriction that the imaging region must be within the X-ray beam formed by the X-ray source and the detector,the imaging field of view of CL is limited by the size of detector.A new CL method with an asymmetric rotational cone-beam scanning geometry,called large field of view CL,is presented to overcome the existing *** can extend the imaging region when the imaging spatial resolution keeps the same as that of the conventional *** can also improve the imaging spatial resolution when the imaging region keeps the same as that of the conventional *** asymmetric configuration can be achieved by offsetting the detector from the conventional symmetric *** does not,however,require new detectors and X-ray source nor alter the scanning mechanical *** filtered back-projection(FBP)reconstruction algorithm and the data truncation smoothing functions have been deduced to reconstruct the images directly from the data acquired with this asymmetric *** performed numerical studies and experiments to demonstrate and validate the proposed approach. Results in these studies and experiments confirm that the proposed method can enlarge the imaging region and improve the spatial *** proposed approach may find applications in the CL system with the rotational scanning geometry.

关键词： computed laminography image reconstruction reconstruction algorithm imaging field of view imaging spatial resolution