Modeling Semantic Web Services with OPM/S - A Human and Machine-Interpretable Language

The World-Wide-Web is now a ubiquitous, global tool, used for finding information, communicating ideas, carry- ing out distributed computation, and conducting business, learning and science. Web services and the Semantic Web are emerging as a powerful infrastructure for distributed computing. However, even though standard methods that define semantics of Web services, such as OWL-S, may aid in the development and deployment of these services, they are hardly designed to be easily understandable and usable by developers. Complexity and lack of accessibility of Web services and the Semantic Web hinders their usage by the information industry. OPM/S, which is based on Object- Process Methodology (OPM), offers a bi-modal visual- lingual representation that is both intuitive for humans and formal for machines. Utilization of ontologies and interop- erability are two issues addressed by the OPM/S modeling environment. Ontologies are expressed as meta-libraries, which are specified in OPM or OWL, and can be dynami- cally linked to semantic Web services in a distributed envi- ronment. Interoperability is achieved using a transparent reuse method that enables dynamic development of Web services and their integration into more complex Web ser- vices. Using a running example, the paper presents OPM/S and its mapping to OWL-S. The benefits and shortcomings are discusses and compared with other OWL-S modeling methods.