Semantic Web Services (SWS), the convergence of Semantic Web and Web Services, is the emerging next major generation of the Web, in which e-services and business communication become more knowledge-based and agent-based. In the SWS vision, service descriptions are built partly upon process ontologies – widely shared ontological knowledge about business processes – which are represented using Semantic Web techniques for declarative knowledge representation (KR), e.g., OWL Description Logic or RuleML Logic Programs.

In this project, we investigate a previously unsolved, crucial problem in representing process ontologies using SW KR: how to represent non-monotonic inheritance reasoning, in which at each (sub)class in the class hierarchy, any inherited property value may be overridden with another value, or simply cancelled (i.e., not inherited). Non-monotonic inheritance is an important, heavily-used feature in pre-SWS process ontologies, e.g., ubiquitous in object-oriented (OO) programming. The advantages of non-monotonicity in inheritance include greater reuse/modularity and easier specification, updating, and merging. We focus in particular on the MIT Process Handbook (PH), a large, influential, and well-used process ontologies repository that is representative in its features for non-monotonic inheritance. W3C’s OWL, the currently dominant SW KR for ontologies, is fundamentally incapable of representing non-monotonicity; so too is First Order Logic. Using instead another form of leading SW KR – RuleML – we give a new approach that successfully represents the PH’s style of non-monotonic inheritance. In this Courteous Inheritance approach, PH ontology knowledge is represented as prioritized default rules expressed in the Courteous Logic Programs (CLP) subset of RuleML.

A prototype of our approach is in progress. We aim to use it to enable SWS exploitation of the forthcoming open-source version of the PH.

• Prof. Abraham Bernstein, DDIS
• Prof. Benjamin Grosof, MIT - Slon School of Management

• A. Bernstein, B. Grosof, "Beyond Monotonic Inheritance: Towards Semantic Web Process Ontologies", Working Paper, University of Zurich, Department of Information Technology, August 2003.