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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,{2.,China 2.college of computer,beihang university,{2.,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

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 {2. 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

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

Radiance-based color calibration for image-based modeling with multiple cameras

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Science China(Information Sciences) 2012年第7期55卷 1509-1519页

作者： ZHAO Xu 1,2.,ZHOU Zhong 1,2.& WU Wei 1,2.1 State Key Laboratory of Virtual Reality Technology and Systems,beihang university,beijing 100191,China 2.School of {2. Science and Engineering,beihang university,beijing 100191,China 1. State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing 100191 China2. School of Computer Science and Engineering Beihang University Beijing 100191 China

Photo-consistency estimation is an important part for many image-based modeling *** paper presents a novel radiance-based color calibration method to reduce the uncertainty of photo-consistency estimation across multiple *** idea behind our method is to convert colors into a uniform radiometric color space in which multiple image data are *** results demonstrate that our method can achieve comparable color calibration effect without adjusting camera parameters and is more robust than other existing ***,we obtain an auto-determined threshold for photo-consistency check,which will lead to a better performance than existing photo-consistency based reconstruction algorithms.

关键词： color calibration photo-consistency estimation multi-camera system image-based modeling

Displacement residual based DDM matching algorithm

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Science China(Information Sciences) 2012年第9期55卷 2090-2101页

作者： ZHANG Lin 1,2.ZHOU Zhong 1,2.LIU Lin 1,2.& WU Wei 1,2.1 State Key Laboratory of Virtual Reality Technology and Systems,beihang university,beijing 100191,China 2.School of {2. Science and Engineering,beihang university,beijing 100191,China 1. State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing 100191 China2. School of Computer Science and Engineering Beihang University Beijing 100191 China

High level architecture(HLA) is the prevailing standard for modeling and *** data distribution management(DDM) service of HLA is defined for reducing the delivery of irrelevant *** key in DDM implementation is the region overlap computation,*** matching between update and subscription *** algorithms usually make a compromise between region fidelity and network *** paper takes both the matching algorithm efficiency and bandwidth cost into *** main contributions are:1) illustrating the relationship between region changes and overlap changes,as helps reduce the number of region matching and then improves the total matching efficiency;2. classifying region updates into two types of data expression,snapshot and *** network traffic will be reduced by transmitting only residual data instead of full region representations ***,a region matching algorithm called displacement residual-based DDM matching(DRBM) is proposed in the *** analysis,algorithm implementation and experiment evaluation are *** results show that DRBM provides better matching performance and significant network payload reductions especially when there is a large number of changing regions.

关键词： distributed simulation high level architecture data distribution management region snapshot region residual

Gray physical interference model based link scheduling algorithms

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Science China(Information Sciences) 2012年第6期55卷 1337-1350页

作者： SU JinZhao 1,2.CAO Jing 1,2.& WU Wei 1,2.1 State Key Laboratory of Virtual Reality and Systems,beijing 100191,China 2.School of computer Science and Engineering,{2.,beijing 100191,China 1. State Key Laboratory of Virtual Reality and Systems Beijing 100191 China2. School of Computer Science and Engineering Beihang University Beijing 100191 China

To improve the concurrent data transmission capability of wireless multi-hop networks,this paper proposes adopting a gray physical interference model instead of using the threshold physical interference *** model allows non-ideal links to be involved in scheduling,under the premise of not affecting the quality of existing transmission *** addition,we design two greedy algorithms to schedule more links with SINR values located in the transition *** results show that a gray physical interference model is more accurate than a threshold physical interference one,the concurrent transmission capability of a network based on the gray physical interference model is significantly increased,and network throughput is increased by 2.%.

关键词： gray physical interference model threshold physical interference model link scheduling concurrent transmission TDMA

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

AutoSyn:A new approach to automated synthesis of composite web services with correctness guarantee

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Science in China(Series F) 2009年第9期52卷 1534-1549页

作者： HUAI JinPeng1,2.DENG Ting1,2.LI XianXian1,2.DU ZongXia1,2.& GUO HuiPeng1,2.1 National Laboratory of Software Development Environment,beihang university,beijing 100191,China 2.School of {2. Science & Engineering,beihang university,beijing 100191,China National Laboratory of Software Development Environment Beihang University Beijing 100191 China School of computer Science & Engineering Beihang University Beijing 100191 China

How to compose existing web services automatically and to guarantee the correctness of the design （e.g. freeness of deadlock and unspecified reception, and temporal constraints） is an important and challenging problem in web services. Most existing approaches require a detailed specification of the desired behaviors of a composite service beforehand and then perform certain formal verification to guarantee the correctness of the design, which makes the composition process both complex and time-consuming. In this paper, we propose a novel approach, referred to as AutoSyn to compose web services, where the correctness is guaranteed in the synthesis process. For a given set of services, a composite service is automatically constructed based on L＊ algorithm, which guarantees that the composite service is the most general way of coordinating services so that the correctness is ensured. We show the soundness and completeness of our solution and give a set of optimization techniques for reducing the time consumption. We have implemented a prototype system of AutoSyn and evaluated the effectiveness and efficiency of AutoSyn through an experimental study.

关键词： business protocol synthesis composite service correctness constraints L* algorithm

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