Mechanism And Application Of Mediators In WSMO Enabling Semantic Web Service

WSMO is the refinement and the extension of WSMF.As one of the most effective modeling frameworks,the aim of designing WSMO is to improve the semantics in the description of Web services and make Web services machine-processable.Mediator is one of the four top level elements of WSMO and used to resolve Web resources heterogeneity.Heterogeneity that hampers interoperability and automatic usages of Web services is an inherent characteristic of open and distributed environments.Developing semantic Web services technology has revealed the four types of heterogeneity, including terminology heterogeneity,representation format heterogeneity,functionality heterogeneity and process heterogeneity.Different types of mediation technology need to be used in order to address various types of heterogeneity.In allusion to the above issues,taking WSMO mediator and its implementation as the research object,the thesis mainly discusses the mediation techniques corresponding to each type of heterogeneity.Firstly,elaborates on WSMO mediator solution to heterogeneity.WSMO defines four types of mediators,which integrate different levels of heterogeneity resolving techniques into a single mediation framework,analyzes the definition,description, topology of WSMO mediator and gives some improvements.Secondly,discusses different levels of mediation technique to address the heterogeneities.The view-based ontology mapping technology has been used to address data heterogeneity problem,therefore the constructing process and the algorithms of ontology mapping are researched.The△-relations has been used to address functional heterogeneity problem,therefore the definition,formal description,construction and application of△-relations are discussed in detail.The choreography technology based on Abstract State Machine has been used to address process heterogeneity problems, therefore choreography concept model and formal expression are elaborated on.By analyzing the interaction of WSMX process mediator with other WSMX components, mediating process of WSMX process mediator is discussed. Finally,studies the practical application of WSMO mediators.Semantic Web services development process based on WSMO,WSML,WSMX is explained through an example of order processing system.Constructing process of ontology and its mapping rules,as well as constructing process of goal choreography and Web service choreography is the focus of the application development.