Reusing Petri Nets Through the Semantic Web Dragan Gašević, Vladan Devedžić FON – School of Business Administration, University of Belgrade, POB 52, Jove Ilića 154, 11000 Belgrade, Serbia and Montenegro gasevic@yahoo.com, devedzic@galeb.etf.bg.ac.yu http://goodoldai.org.yu Abstract. The paper presents the Petri net ontology that should enable sharing Petri nets on the Semantic Web. Previous work on formal methods for representing Petri nets mainly defines tool-specific Petri net descriptions (i.e. metamodels) or formats for Petri net model interchange (i.e. syntax). However, such efforts do not provide a suitable model description for using Petri nets on the Semantic Web. This paper uses the Petri net UML model as a starting point for implementing the Petri net ontology. The UML model is then refined using the Protégé ontology development tool and the Ontology UML profile. Resulting Petri net models are represented on the Semantic Web is using XML- based ontology representation languages, Resource Description Framework (RDF) and Web Ontology Language (OWL). We implemented a Petri net software tool as well as tools for the Petri net Semantic Web infrastructure. 1 Introduction The main idea of this paper is to propose a suitable way for Petri nets [1] to be used on the Semantic Web, i.e. to enable full semantic interoperability of Petri net models. Currently, Petri net interoperability is possible at the level of syntax for model sharing. It was first introduced in [2], where the authors said that it would be very useful if Petri net researchers could share their Petri net model descriptions. That way more software tools could be used for analyzing the same model. So far, all Petri net interchange attempts have been mainly tool-specific, but with very low (or without any) general acceptance. The Petri Net Markup Language (PNML) [3] is a recent Petri net community effort that tries to provide XML-based model sharing. PNML tends to be a part of the future ISO/IEC High-level Petri net standard [4]. A particularly important advantage of this approach is that XML documents can be easily transformed using eXtensible Stylesheet Language Transformations (XSLT) into other formats (that need not necessarily be XML-based). A suitable way to represent Petri nets is needed in order to reuse them more effectively on the Semantic Web. It requires defining the Petri net ontology for semantic description of Petri net concepts and their relationships. The Petri net ontology enables describing a Petri net using Semantic Web languages (e.g. RDFS, and OWL) [5] [6]. Petri nets described that way can be inserted into other, non-Petri net XML-based formats, such as Scalable Vector Graphics (SVG, the XML-based WWW Consortium (W3C) standard for 2D vector graphics) [7]), which makes J. Davies et al. (Eds.): ESWS 2004, LNCS 3053, pp. 284-298, 2004.  Springer-Verlag Berlin Heidelberg 2004