An introduction to modular process nets

Modular process nets are a graphical and formal notation for the representation of technical and business process models containing concurrent activities. Originally this class of Petri nets was developed for the modeling, analysis, simulation and control of workflows and computer-based process control systems, but it is also suitable for use in all other areas where a formal but comprehensible description of complex processes is needed. After a description of the basic aims and design decisions for modular process nets, the report gives a brief introduction to low-level Petri nets including different types of transition rules and aspects of the descriptive and prescriptive use of process models. The main and most innovative points which are explained in more detail are the introduction of a hierarchical module concept for nets and the definition of elementare process nets. The module concept is part of a more general ("object-based") approach to Petri nets allowing several types of ab straction, whereas the main points of elementary process nets are synchronous and asynchronous communication between separately interpreted net instances via events and token passing. Modular process nets are low-level Petri nets equipped with these module and communication concepts and optionally enhanced by die use of a task concept, a method known from the areas of computer-supported cooperative work (CSCW) and work-flow management. Because the report is aimed at a systematic and easy-to-understand introduction to modular process nets, it provides a precise explanation of this net class which is kept as informal as possible and enhanced by some typical application examples