Bridging the Gap between Abstract and Concrete Services - A Semantic Approach for Grounding OWL-S

OWL-S [1] is one of the emerging standards for the semantic description of web services in order to enable their automatic discovery, execution and composition by software agents. An important task within automatic execution of an OWL-S service is the bi-directional mapping between semantically higher level OWL-S service parameter descriptions and primitive XML Schema types of its grounding. OWL-S proposes to utilize XSL Transformations (XSLTs) for the mapping between these representation levels. However, this approach has a substantial shortcoming due to the fact that one OWL model can have many different RDF serializations whereas each requires a specific XSL stylesheet in the worst case. This severely limits the practical applicability of OWL-S in general. In this paper we present a simple approach of OWL-S parameter type mappings on a semantical basis. We therefore define an RDFS ontology of RDF Mappings that enable bi-directional mappings between OWL and XML Schema types. We show how to integrate RDF Mappings into the OWL-S grounding ontology and prove their feasibility by describing our prototypical implementation.