Process model repositories and PNML

Bringing system and process models together in repositories facilitates the interchange of model information between modelling tools, and allows the combination and interlinking of complementary models. Petriweb is a web application for managing such repositories. It supports hierarchical process models, represented in a standard format, PNML (the Petri Net Markup Language). Properties can be associated with models, with values supplied manually or by applying tools. This design allows for easy interfacing with tools for modelling and analysis. Petriweb's first application is a repository for use in research and education that illustrates theoretical properties of Petri nets with examples and counterexamples. To make the creation of examples as easy and ??exible as possible, we created Yasper (Yet Another Smart Process EditoR). Yasper combines the benefits of a generic diagram editor with unique features for Petri net editing, and interfaces with Petriweb and other tools through PNML import/export. Petriweb's design is closely tied to that of PNML; it can provide good support for PNML's extensibility. PNML is suitable as a mechanism to define document formats for Petri net types, but conflicts between such definitions are still hard to detect; we propose additions to improve this situation.