【作者】 卢锦运；

【导师】 张为群；

【作者基本信息】 西南大学 ， 计算机软件与理论， 2010， 硕士

【摘要】 随着Web服务技术的快速发展和应用,Web服务的数量与日俱增,提供的功能也越来越多样化。然而,单个Web服务提供的功能有限,很多时候都不能满足用户多样性的需求,这就需要将已有的Web服务进行组合,以创造出功能更为强大更能满足用户需求的复合服务。另一方面,Web服务的服务质量QoS对于服务的成功应用也非常关键,它是服务请求者能从众多具有相同功能的服务中选择出具有最好服务质量的服务的主要依据。因此如何快速、准确、高效地组合已有的分布在Internet中的各类服务,实现服务之间的无缝集成,同时提供具有QoS保证的Web服务以满足用户的需求已经成为一个迫切需要解决的问题。本文通过语义Web和Web服务组合技术的学习,在已有研究的基础上提出了一种基于与或图的语义Web服务自动组合方法SCBAO,主要从以下几个方面进行探讨和研究：(1)本文给出了一种语义Web服务描述方法,该方法对Web服务本体描述语言OWL-S进行QoS扩展,并将扩展后的OWL-S用来描述Web服务,使得Web服务同时具有语义信息和QoS信息。(2)本文给出了一种基于Web服务输出的倒排索引结构,并在此结构基础上通过为服务库中所有注册服务的语义输出建立倒排索引记录,即为每个服务的语义输出维护一个能够生成该输出的服务列表,以此来降低服务搜索空间,提高服务搜索的效率和准确性进而降低创建服务组合与或图的时间开销。(3)本文提出了一种基于与或图的语义Web服务自动组合方法SCBAO,该方法将基于图搜索的Web服务组合方法与语义Web服务自动组合方法相结合,同时能够将搜索空间受限于服务组合与或图中,提高了Web服务自动组合的成功率及效率。在对Web服务进行语义描述后,SCBAO分为2步实现服务组合的目标：1)服务组合与或图的自动生成；2)最佳组合图的选取。(4)本文通过实例来说明SCBAO方法的执行过程,并通过仿真实验验证了SCBAO的可行性和有效性。仿真实验表明SCBAO方法能够提高Web服务组合效率和成功率。更多还原

【Abstract】 With the rapid development and application of Web service technology, the number of Web service is increasing very fast and the functions of Web services are more and more diversified. However, the function of a single Web service is limited and it often fail to meet the diverse needs of customers. So in order to create a composite service which is more complex, more powerful and meeting users’demand better, we need compose the existing Web services. On the other hand, the quality of Web service is also critical to Web services, which is the main base for people to choose the best Web services from a number of Web services which have the same function. It has become a crucial problem to be solved that composing the existing Web services in the Internet to integrate these services seamlessly and to provide the Web services with QoS to meet customers’needs rapidly, accurately and efficiently.By studying the technology of Semantic Web services and Web services composition, based on the previous research results, we propose an approach based on AND/OR graph to compose semantic Web services automatically. The main focuses of this paper are as follows:Firstly, this paper proposes a description method of semantic Web services, this method extends OWL-S with QoS information. In order to let Web services have the semantic and QoS information, we describe the Web services with the extended OWL-S documents.Secondly, this paper proposes an inverted indexing structure based on the outputs of Web services. On the basis of this structure, we generate inverted indexing record for every semantic output to reduce the services search space and improve the efficiency and accuracy of services search and thus we reduce the cost of the SCAOG generation.Thirdly, this paper proposes a method of automatic semantic Web services composition based on AND/OR graph named SCBAO, SCBAO improves successful rate and efficiency of Web services composition through combining graph-based search methods and Semantic Web Service Composition methods and limiting the search space within SCAOG After being described by semantic info, Web services will be composed by our approach for a user through two steps:1)Automatically create services composition AND/OR graph;2)Searches for the optimal composition graph.Finally, we explain the implementation process of SCBAO approach by examples and we validate SCBAO approach’s feasibility and validity by a simulation experiment. Simulation experiment results shows SCBAO approach can improve both the effective and successful rate of Web services composition.更多还原