论文标题:GIS服务共享若干关键问题的研究与实现
The Research of Several Important Problems in GIS Service Sharing System
论文作者
论文导师 杨宜民,论文学位 博士,论文专业 控制理论与控制工程
论文单位 广东工业大学,点击次数 98,论文页数 160页File Size9580K
2007-04-01论文网 http://www.lw23.com/lunwen_92976347/
Agent; Web Service; Ontology; GIS; Service Sharing; Service Description; Service Matching; Service Combining
GIS系统把各种地理信息和有关视图结合起来，有着广泛的应用前景，被公认为是21世纪的支柱产业之一。但是，在GIS发展过程中出现的各种GIS系统存在着数据格式不一致、不能兼容及不能相互调用等问题，造成GIS的发展和应用受到了很大的制约。虽然OGC等组织提出采用Web服务作为GIS服务共享的手段，然而这些问题依然得不到很好地解决。 本文在综合、分析、说明GIS系统的产生、发展、研究意义及研究现状的基础上，对制约GIS系统的发展及应用的若干问题作了较深入的研究。本文的主要内容： 1．服务描述的研究。提出并采用具有能力、意图、信念、愿望等Agent特性的标志语言WAML(Web Agent Marked Language)作为GIS服务描述语言。描述了WAML的各个特性之间的关系，将OWL嵌入WAML实现WAML中概念的本体描述，并利用孩子-兄弟树结构的概念格树实现WAML中的等价类信息描述。采用WAML进行服务描述可以更好地描述服务的特点。 2．服务描述本体扩展的研究。本体扩展采用基于树结构的概念格树扩展方法。在扩展的过程中进行本体复杂度度量和本体冲突检测。本体复杂度度量采用孩子-兄弟树的深度-宽度与重要因子结合的方法。本体冲突检测针对WAML描述的孩子-兄弟树的特点，给出了常见冲突消解方法。本体扩展方法切实可靠，实验证明，经过本体扩展后的服务匹配查全率有较大提高。 3．服务匹配的研究。采用概念格与向量空间相结合的方法实现服务匹配。概念格法可用于计算同一个本体中概念之间的相似度，与向量空间法结合后可以实现不同本体之间概念的相似度计算。实验证明，采用此方法具有较高的查全率和查准率，且耗时较少，可以较好地完成服务匹配。 4．服务组合的研究。提出了用WAML语义生成Web服务组合链。首先给出基于WAML的服务组合的算法，并导出服务组合图，然后利用最短路径算法得到最佳服务调用路径，作为服务调用链。最后对算法的实现中出现图的环问题和图的修正问题进行了讨论。实验证明，服务组合算法可行，所得到的服务调用链符合用户的要求。 5．GIS服务共享系统的研究。利用多Agent技术将GIS服务共享系统的各部分有机地组合起来。首先研究了基于多Agent的GIS服务共享系统的体系结构，对各个Agent的模型、功能和合作机制作了说明，然后研究Agent之间的通信语言和通讯语义及基于SOAP的Agent通信方式。实验证明基于SOAP的通信系统效率满足系统的要求。采用多Agent技术使系统具有适应性强、效率高、并发性和容错性好等优点。 本文最后阐明基于多Agent的GIS服务共享系统的实现，并说明上述研究成果的正确性和有效性。首先给出了各个Agent详细的实现方法，然后介绍了GIS服务共享系统的各子系统及其开放的服务，最后给出了一个基于GIS服务共享的智能交通子系统实例。
GIS has combined the geography information and videotext. It is regarded as one of the most important businesses in 21 century. But in the development, there are many kinds of GIS. All of them have different data formats and they can"t make use of each other, it has restricted the development of GIS. Although OGC appeals to use web service to solve this problem, it is not solved completely. This paper firstly introduces the development history and research technology of GIS, then goes deep to the problems that have restricted the development of GIS. The main content of the paper is: 1. Research on web service description. The web agent marked language (WAML) is put forward as the GIS service describe language. The relation between each parts of the WAML is described. OWL in WAML is used to describe the ontology of WAML. Child-brother tree is used for describing sibling classes. WAML can describe service description better. 2. Research on extending service description ontology. Ontology extending is based on concept tree by the character of tree. During the extending, the complexity and conflict of the ontology are taken into account. The complexity of the ontology is calculated by the depth and width of the concept tree. Ordinary conflicts settle method is put forward. It is shown in experiment that ontology extending can increase the search results. 3. Research on service description matching. Concept tree and vector space are used in service matching. Concept tree is used in calculating the concept distance in the same tree. By combined with vector space, it can calculate the distance of different keywords in different trees. In experiment, more and better results are got in service description matching. 4. Research on service combination. The method of using the semantic WAML to generate a web service chain is put forward. Firstly the arithmetic of service combination is present, then the Dijstra arithmetic is used to get the best route, At last several problems such as loop and graph modifying are solved. It is proved the combination arithmetic can provide the user useful service chains. 5. Research on GIS service sharing system. Multi-agent is used to combine the parts of GIS service sharing system. Firstly the structure of GIS service sharing system is discussed. Model and cooperate method are introduced, and then the communication language and communication method based on SOAP are worked over. It is proved in experiment that communication method based on SOAP can satisfy the user. By using agent, the system can run more quickly and more strongly. A GIS service sharing system is realized in the last chapter of the paper. By this way, our research is proved to be correct. Firstly the method to implement every agents is put forward, then several GIS subsystems which will be used in GIS sharing system are realized, and the services of subsystems are introduced, at last an ITS subsystem based on service sharing is introduced.
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