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Constructing a core framework of visual engine for Digital Earth system

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Science China(Technological Sciences) 2010年第S1期53卷 38-43页

作者： weng jingnong,WANG YingJie & CAI Heng School of Computer,Beihang University,Beijing 100191,China Beihang Univ Sch Comp Beijing 100191 Peoples R China

A visual engine is the core of a Digital Earth *** is a wide variety of functional requirements in Digital Earth system and different requirements correspond to different *** on the development of the visual engine for ChinaStar,a 3D Digital China prototype software platform,and analysis of 3D Digital Earth platforms such as Google Earth,Virtual Earth,Skyline,etc,are discussed.A common core framework for a visual engine is proposed in this paper to construct a visual engine and then with this framework various Digital Earth application systems can be developed *** parametric model of the Earth,scheduling and optimization in visual field,choice of 3D graphics library,and designing component-based visual engine framework of Digital Earth are discussed in *** addition,the relationships among these four basic components and the construction of visualization applications of Digital Earth by this method are also discussed.

关键词： Digital Earth visual engine COMGIS core framework

Distributed GIS oriented generalized image pyramid and its practice

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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 Science and Engineering,Beihang University,Beijing 100191,China 1. School of Computer Science 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

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

Probabilistic composition of cone-based cardinal direction relations

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Science China(Technological Sciences) 2008年第S1期51卷 81-90页

作者： LIU Yu1,TIAN Yuan1 & weng jingnong2 1 Institute of Remote Sensing and Geographical Information Systems,Peking University,Beijing 100871,China 2 College of Software,Beihang University,Beijing 100083,China Peking Univ Inst Remote Sensing & Geog Informat Syst Beijing 100871 Peoples R China Beihang Univ Coll Software Beijing 100083 Peoples R China

Composition tables play a significant role in qualitative spatial reasoning (QSR). At present,a couple of composition tables focusing on various spatial relations have been developed in a qualitative approach. However,the spatial reasoning proc-esses are usually not purely qualitative in everyday life,where probability is one important issue that should be considered. In this paper,the probabilistic compo-sitions of cone-based cardinal direction relations (CDR) are discussed and esti-mated by making some assumptions. Consequently,the form of composition result turns to be {(R1,P1),(R2,P2),…,(Rn,Pn)},where Pi is the probability associated with relation Ri. Employing the area integral method,the probabilities in each composi-tion case can be computed with the assumption that the target object is uniformly distributed in the corresponding cone regions.

关键词： spatial reasoning cardinal direction relations probabilistic composition

Topological relations between directed lines and simple geometries

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Science China(Technological Sciences) 2008年第S1期51卷 91-101页

作者： GAO Yong1,ZHANG Yi1,TIAN Yuan1 & weng jingnong2 1 Institute of Remote Sensing and Geographic Information System,Peking University,Beijing 100871,China 2 Colledge of Software,Beihang University,Beijing 100083,China 1. Institute of Remote Sensing and Geographic Information System Peking University Beijing 100871 China2. Colledge of Software Beihang University Beijing 100083 China

Directed lines are fundamental geometric elements to represent directed linear en-tities. The representations of their topological relations are so different from those of simple lines that they cannot be solved exactly with normal methods. In this paper,a new model based on point-set topology is defined to represent the topo-logical relations between directed lines and simple geometries. Through the inter-sections between the start-points,end-points,and interiors of the directed lines and the interiors,boundaries,and exteriors of the simple geometries,this model identifies 5 cases of topological relations between directed lines and points,39 cases of simple lines,and 26 cases of simple polygons. Another 4 cases of simple lines and one case of simple polygons are distinguished if considering the exteri-ors of the directed lines. All possible cases are furthermore grouped into an exclu-sive and complete set containing 11 named predicts. And the conceptual neigh-borhood graph is set up to illustrate their relationship and similarity. This model can provide a basis for natural language description and spatial query language to present the dynamic semantics of directed lines relative to the background fea-tures.

关键词： topological relation directed line simple geometry intersection model

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

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Science China(Technological Sciences) 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

On 3D simulation of moving objects in a digital earth system

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Science China(Technological Sciences) 2008年第S2期51卷 123-132页

作者： weng jingnong1,WU Lun2,HUANG Jian1,WANG Yang1,YANG Xue1 & HU Bin1 1 College of Software,Beihang University,Beijing 100191,China 2 Institute of Geographical Information System and Remote Sensing,Peking University,Beijing 100871,China College of Software Beihang University Beijing 100191 China Institute of Geographical Information System and Remote Sensing Peking University Beijing 100871 China

"How do the rescue helicopters find out an optimized path to arrive at the site of a disaster as soon as possible?" or "How are the flight procedures over mountains and plateaus simulated?" and so *** this paper a script language on spatial moving objects is presented by abstracting 3D spatial moving objects' behavior when implementing moving objects simulation in 3D digital Earth scene,which is based on a platform of digital China named "ChinaStar".The definition of this script language,its morphology and syntax,its compiling and mediate language generating,and the behavior and state control of spatial moving objects are discussed *** addition,the language's applications and implementation are also discussed.

关键词： Digital Earth ChinaStar moving object script language

Methodologies and applications in Digital China

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Science Bulletin 2012年第Z2期 3761-3768页

作者： weng jingnong *,RAFIQUE Irfan & ABBASI Maissom Qanber School of Computer Science and Engineering,Beihang University,Beijing 100191,China

关键词： Digital China spatial information and technology new research advancement

Efficient visualization techniques for high resolution remotely sensed data in a network environment

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Science China(Technological Sciences) 2008年第S1期51卷 124-134页

作者： weng jingnong1,WU Lun2,HUANG Jian1,XIA YuBin3 & CAI Heng1 1 College of Software,Beihang University,Beijing 100083,China 2 Institute of Geographical Information System and Remote Sensing,Peking University,Beijing 100871,China 3 College of Computer,Beihang University,Beijing 100083,China 1. College of Software Beihang University Beijing 100083 China2. Institute of Geographical Information System and Remote Sensing Peking University Beijing 100871 China3. College of Computer Beihang University Beijing 100083 China

There are three major research hotspots in efficient visualization techniques of high resolution remotely sensed data in network environment: the data organiza-tion and access in disk storage,the image data stitching and fitting methods,and the network transfers and access. In this paper a new method of "Big File" organi-zation for improving the storage access efficiency of high resolution remote data is presented; a "virtual data source" concept is introduced to solve the stitching problem of remotely sensed data from different sources with different resolutions; a remotely sensed data access engine design based on ATL technique is discussed to process the network transfers and access of remotely sensed data. All these techniques have been adopted in a prototype of digital China named "ChinaStar".

关键词： high resolution remotely sensed data spatial index pyramid model LOD Big File