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Research On The System Framework, Service Architecture And Service Composition Technology Of Spatial Information Grid

Posted on:2005-02-09Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y TangFull Text:PDF
GTID:1118360155972207Subject:Information and Communication Engineering
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With the increasing requirements of spatial information application, problems such as huge amounts of distributed data, heterogeneous data format, complexity of data processing, and etc, have become obstacles for sharing and integration of spatial information. Traditional spatial information techniques can not solve all these application problems. It is imperative to introduce new techniques to manage, process, and integrate distributed heterogeneous spatial information. These new techniques should provide support to establish an integrated application environment for effective and efficient spatial information services. On this background, the National High Technology Research and Development Program of China (863 program) proposes a novel concept, i.e. Spatial information Grid (SIG), aiming at integrating some new techniques, including grid computing, OpenGIS specifications and Web services, to solve the existing application problems and satisfy multi-layer application requirements.Spatial Information Grid (SIG) is a spatial information infrastructure with the ability of providing services on demands and implementing sharing, integration, organizing, and collaboration of enormous distributed spatial information. At present time, the research on theories and key technologies of SIG is at the initial stage. This thesis investigates SIG from the viewpoint of spatial information application. Since SIG adopts services as its application model, our research focuses on system architecture, service framework and service composition. We built an experimental system to evaluate our research on SIG. Our work provides theoretical and technical bases for succeeding research and practical applications of SIG The main contributions of this thesis are as follows:(1) The system architecture of SIG is presented and described from three aspects, i.e. application architecture, technical architecture and constitution architecture. It provides holistic framework and top-level guidance for studying SIG technologies, designing SIG experimental system, and implementing SIG representative applications.(2) The SIG service framework is studied and built. We present an open seven-layer SIG service protocol stack, the taxonomy and application patterns of SIG services. Moreover, wepropose Spatial Information Elementary Service (SIES) as a novel concept to compartmentalize function granularity and application levels of SIG services <>(3) The application process and implementation methods of two types of SIG services are analyzed and presented, i.e. data service, analyzing and processing service. We design and implement nephogram service and space syntax analysis service as representative SIG service instances. As for space syntax analysis service, a new data model named Space Syntax Object-Oriented Data Model (SSOODM) is proposed, and the data index method of space syntax analysis is presented based on R tree as well.(4) The technical framework of SIG service composition is founded. And the ontology of SIG (SIGonto) is presented as a formal, explicit specification of shared SIG conceptualization. We define SIG service Semantic Description Language (SSDL) to describe the semantics of SIG services. Based on SSDL, a new concept, i.e. Matching Degree (MD) is introduced, and a new algorithm is proposed to compute the semantic MD between an application request and a SIG service, hence the semantic matching and selection of SIG services according to the application requests are implemented.(5) A novel workflow model for SIG service composition is proposed based on Petri net and graph theory to provide formal modeling method for SIG service composition process, i.e. Service/Resource Net (SRN). Furthermore, we introduce a novel algebraic structure of SIG service composition, and present its algebraic operators and properties. On the other side, some analysis and evaluating methods of SRN are presented to validate the correctness and practicability of the process model, including linear temporal inference rules, the algorithm of computing key paths of service composition process, and the matching algorithm of multiple requests and multiple SIG services.(6) The execution technic of SIG service composition is studied. We inteoduce two new concepts to implement dynamic selection of SIG service in composition process, i.e. Service Family (SF) and Service Dynamic Selection Model (SDSM). Hence, an innovative dynamic service selection algorithm is proposed based on Multiple Attribute Decision Making (MADM) method to select the optimum service as the service instance for composition process execution. On the other side, we study and define SIG Service Request Language (SSRL) and SIG Service Task Language (SSTL) to describe user requirements and SIGservice composition process. Based on SSRL and SSTL, the SIG service composition process can be executed expediently and purposefully.(7) Based on the research achievements presented above, we design and impement a SIG experimental system. The experiment results show that our research achievements are effective and practical.
Keywords/Search Tags:Spatial Information Grid(SIG), System Architecture, SIG Service, Space Syntax Analysis, SIG Service Composition, Service/Resource Net(SRN), Dynamic Service Selection, Geological Survey
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