Interoperable Petri net models via ontology
International Journal of Web Engineering and Technology
The paper presents a Petri net infrastructure that should provide sharing Petri nets on the Semantic Web. Previous solutions only provide model interchange mechanisms between Petri net tools. The Petri net ontology is a central part of our solution. The ontology is closely related to the Petri Net Markup Language (PNML) -an ongoing Petri net community sharing effort. We developed the Petri net ontology using both UML and Protégé tool, whereas we use RDF and OWL to represent the ontology. We
... emented a Petri net software tool -P3 -that tool can be used to convert the Petri net ontology compliant models to the formats of current Petri net tools (e.g. DaNAMiCS, Petri Net Kernel, PIPE) using eXtensible Stylesheet Language Transformations (XSLT). In order to show how the ontology can be used we developed a simple educational Web application that uses RDF-annotated ontology-based Petri net learning materials. . His current research interests are in the area of ontology development, Semantic Web, XML-based interoperability, integration between software engineering and knowledge engineering techniques, learning technologies and Petri nets. So far, he has authored/co-authored more than 80 research papers, several book chapters, and one book. He has been a referee and PC member for several international conferences. He can be reached at http://www.sfu.ca/~gasevic. Vladan Devedžić is an associate professor of computer science at the Semantic Web, intelligent reasoning, software engineering, and applications of artificial intelligence techniques to education and medicine. So far, he has authored/co-authored more than 220 research papers published in international and national journals and conferences. His major long-term professional goal is a continuous effort to bring close together the ideas from the broad fields of intelligent systems and software engineering. He has developed several practical intelligent systems and tools, and actively participates to several ongoing projects in industry and in academia. He can be reached at http://fon.fon.bg.ac.yu/~devedzic. D. Gašević and V. Devedžić Ontologies. So far, only one Petri net ontology has been developed. Perleg and her colleagues developed a Petri net ontology using Protégé and a specific graphical user interface (GUI) that extends the standard GUI of the Protégé tool  . Actually, this GUI provides graphical tools for all Petri net concepts (Places, Transitions, and Arcs). In addition, the Petri net ontology is represented in RDFS, and concrete Petri net models are represented in RDF. This solution gives a solid starting point for defining the Petri net ontology. However, it has serious limitations. It covers only Time Petri nets, and no other kinds of Petri nets. It neither defines Petri net structuring mechanisms, nor provides precise constraints (e.g. types of an arc's source and target nodes that can be done using Protégé Axiom Language (PAL) constraints). Finally, it does not enable using other ontology languages for representing the Petri net ontology (e.g. DAML or OWL). This ontology can give us guidelines how to define conceptualization, properties, and taxonomy of the Petri net ontology. Syntax. A lot of work has been done in defining and using Petri net syntax. We can classify present syntax in categories as follows: general-purpose and tool-specific. Toolspecific syntax are, for example, those that are used in the following tools: DaNAMiCS (regular text syntax) and Renew (XML). Abstract Petri Net Notation (APNN) is the first attempt to define a general-purpose Petri net syntax (i.e., it has ability to describe different Petri net dialects) . The abstract notation for each Petri net class is defined in BNF. This grammar is useful from the extensibility and modularity perspectives. The Petri net community is working for three years already on development of the Petri Net Markup Language (PNML)  that might become a part of the future ISO/IEC Highlevel Petri nets standard   . The PNML is a proposal that is based on XML. PNML specification is based on the PNML metamodel that formulates the structure of PNML documents. Actually, this metamodel defines the basic Petri net concepts (places, transitions, arcs), as well as their relations that can be presented in a PNML document. PNML, being more mature, is currently supported (or will be supported soon) by many Petri net software tools, for instance: Petri Net Kernel (PNK), CPN Tools, Worflan, PIPE, PEP, VIPtool, etc. For educational purposes, we developed P3, a Petri net tool that supports PNML  (see Section 6 for details). We believe that Petri net syntax give main contribution for Petri net ontology with: concepts, properties and their relations.