A semantic description framework for web services descriptions and matchmaking

Abstract

In the M.Sc thesis, the project focuses on the problems of semantic-based representing and retrieving Web services based on the capabilities of services. Service description is critical to application development in Web service environments. There are a number of motivated research developed for representing Web services by different research organisations such as WSDL and UDDI. Both of them are existing standards for Web services. WSDL is designed to provide descriptions of message transport and interface used by each service. UDDI provides a registration structure for businesses and services, and describes businesses and services using their physical attributes in terms of names, addresses, human-understandable business descriptions and service descriptions. Both WSDL and UDDI lack semantic-based description information and a number of essential factors of service capabilities are out of the current description frameworks such as the degrees of service capabilities, relationships between users and services. Moreover, the discovery mechanism provided by UDDI is "exact match” search on the business or service names and descriptions. Actually, service providers and service consumers may have very different background and knowledge, so they do not usually share the same description information for the same item in their minds. It is difficult to locate the proper Web services if users do not express their requirements exactly same with the service provider advertisements. With the consideration of above problems, the development of techniques to semantically represent Web services is necessary for the Web service description and matchmaking. To address the above problems, we identify several requirements and essential factors that a Web service description framework should have and propose a semantic rich modelling framework to integrate these factors to describe Web services capabilities in unambiguous and computer-understandable forms with ontology. The novel description framework is the Business-Service-User (BSU) framework which provides a semantic based description information for business, service and user. Another important goal for the BSU framework is to integrate with current Semantic Web markup languages so that the framework can be easily accessed and understood by the computer. In this thesis, we use the semantic web language OWL to represent the BSU framework and the new semantic description language is called OWL-BSU, which is a computer-interpretable description of the business, service and user. Moreover, a simple and effective matching algorithm is designed to calculate the semantic relationships between service consumers requirements and service descriptions. To make our approach work in the real world, we develop a semantic Web services search engine, which integrates OWL-BSU and the matching algorithm on the top of UDDI registry. The evaluation experimental results have shown that our approach can achieve a great improvement on retrieval performance in terms of recall and precision, comparable to the existing UDDI registry.