Flexible Service Offering with Semantic Policies

One of the challenges in Service Oriented Computing consists in supporting service discovery and composition according to the so-called non functional properties (NFP). In this paper we propose a linguistic framework to describe NFPs of services independently of the grounding technology by means of semantic Web technologies. In particular, the approach is based on an extension of the Web Service Modeling Language (WSML). The linguistic framework supports flexible NFP representations by allowing (i) to reuse existent models and ontologies, (ii) to represent both the definition of single NFPs and clusters of NFPs grouped into policies. A policy collects a set of related and possibly interdependent properties to form a single entity that can be referenced and discovered. As a result, definitions of NFPs can be independent of specific services, and vice versa, so to support flexible associations.