Query languages for semantic web services

Abstract

Even though service discovery is one of the vital steps in Web service invocation, service requests are usually expressed by rather simple means. While syntax-based service descriptions are usually addressed using keyword-based queries, Semantic Web Services are queried using "perfect" service descriptions. Hence, a service requester is not able to control the outcome of the discovery process in-depth by specifying similarity ranges or to explicitly state which syntaxand semantic-based parts of a service description should be addressed. In this paper, we present an analysis of current approaches to service request formulation and identify requirements a query formalism for Semantic Web Services should fulfill. Furthermore, we give a brief preview on SWS2QL, a SPARQL-based query language for Semantic Web Services.