Abstract

The recent growth of using agents in representing web services is causing difficulties in finding specific types of services. This problem usually arises because matchmaking techniques for services are often based on string comparison and service providers might neglect to provide enough or appropriate keywords for the matchmaking process. In this thesis, we report on an approach that makes use of formal ontologies and automated reasoning services in order to improve the matchmaking process. The suggested approach is based on the Ontology Web Language (OWL), the OWL reasoner RACER, and the agent framework DECAF. The use of OWL ontologies is twofold. First, ontologies were used in order to express the particular knowledge of agents. These ontologies are grounded by referring to a so-called common upper ontology providing the necessary glue between the different agent domains. Second, with the help of OWL-S, a standard OWL ontology designed for specifying service descriptions, agents describe formally their offered web services. Our approach depends on a middle-ware agent called matchmaker, which will be in charge of matching required services to proper provider agents. Due to the use of OWL ontologies, the matchmaking process can be reduced to query processing and ontology reasoning implemented by the RACER system. The suggested approach has been demonstrated using a bioinformatics scenario, where several agents will take care of representing several web services. These agents will be providing composite services that the biology scientists might need. The communication protocol is based on OWL-S and allows seeker agents to adapt smoothly to dynamically changed web service descriptions of provider agents.