A Method Of Automatic Semantic Web Services Composition Based On AND/OR Graph

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.