检索结果-南通市图书馆

Complex conforming Delaunay triangulation

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2010年第6期53卷 1130-1140页

作者： MENG XianHai 1, LI JiGang 1, YANG Qin 1, CAI Qiang 2.& CHEN QiMing 3 1 NLSDE, school of computer {2. and engineering, beihang university, beijing 100083, china 2.school of computer {2.s, beijing Technology and Business university, beijing 100037, china 3 school of Mechanical engineering and Automation, beihang university, beijing 100083, china 1. NLSDE School of Computer Science and Engineering BeiHang University Beijing 100083 China2. School of Computer Sciences Beijing Technology and Business University Beijing 100037 China3. School of Mechanical Engineering and Automation BeiHang University Beijing 100083 China

A novel algorithm of conforming Delaunay triangulation for curved geometry is presented in the paper.A progress has been made for the problem puzzled Delaunay refinement where curved constraints cannot be accepted as input *** algorithm is based on a new sufficient condition for the existence of constraints in *** requires computing only the intersection between constraints and Voronoi edges or faces instead of the circum-sphere of curved *** the termination of the algorithm when small input angles exist in constraints, a weighted method is applied to ensure that the algorithm can terminate under any *** two-dimensional and three-dimensional results are also *** is shown that the algorithm has the capability of dealing with both linear and nonlinear constraints in a consistent way, without the need of maintaining triangular meshes on face constraints.

关键词： mesh generation Delaunay triangulation conforming curved constraints tetrahedralization weight

Reliability-aware automatic composition approach for web services

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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,{2. 2.school of computer science and engineering,beihang university,beijing 100191,{2. 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

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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 {2.,beihang university,beijing 100191,china 2.school of Software,beihang university,beijing 100191,china 1. school of Instrument science and Opto-Electro {2. 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

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

在线全文

学校读者我要写书评

暂无评论

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,{2. 2.school of computer science and engineering,beihang university,beijing 100191,{2. 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

Distributed GIS oriented generalized image pyramid and its practice

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Technological sciences) 2010年第S1期53卷 99-104页

作者： XIA YuBin,PANG PeiYu & WENG JingNong school of computer {2. and engineering,beihang university,beijing 100191,china 1. school of computer {2. and engineering Beihang University Beijing 100191 China

Gaussian pyramid framework (GPF) and Laplacian pyramid framework (LPF) are the two main frameworks used for transmission and structure of spatial image and geometric *** is the main approach for progressive transmission of spatial image *** paper discusses the issues in structure,transmission and storage efficiency of spatial data in the current spatially distributed visualization *** in the paper a novel approach is introduced to structure and store spatial data based on the *** new approach builds (spatial) index for transformed frequency data within different ranges based on splitting high-frequency and low-frequency data by biorthogonal *** approach decreases the storage consumption and network data traffic for transmission while enables the progressive transmission of spatial image.

关键词： redundancy spatial index progressive transmission generalized pyramid structure Laplacian pyramid framework

Displacement residual based DDM matching algorithm

在线全文

学校读者我要写书评

暂无评论

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,{2. 2.school of computer science and engineering,beihang university,beijing 100191,{2. 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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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.,beihang university,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

Complexity of synthesis of composite service with correctness guarantee

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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, {2. 2.3} of Mathematics and System science, beihang university, beijing 100191, {2. 3school of computer science and engineering, beihang university, beijing 100191, {2. 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 2.XPTIME, 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 2.XPTIME for CTL and CTL*, respectively.

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

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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,{2. 2.school of computer science & engineering,beihang university,beijing 100191,{2. National Laboratory of Software Development Environment Beihang University Beijing 100191 China school of computer {2. & 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