Attributed Hierarchical Petri Nets

PACE respectively the semigraphical MSL modelling language are based on attributed extended Petri nets. In order to construct such a net the elements are directly selected, positioned and connected with the mouse.

Next to the classical elements of Petri nets PACE offers two more elements: modules and channels. Modules allow the construction of hierarchical models and by this the mapping of the real structure of objects into a model. They allow also the modeling of reusable partial networks and with that the construction of application libraries. Channels summarize multiple combinations between modules.

In a Petri net an optional number of tokens wander asynchronous and parallel over transitions from place to place. The tokens e.g. correspond to a customer order or to a part contained just in the manufacturing process. The attributes of the tokens contain the detailed information about the task or the part as serial number, desired delivery date, costs, scales or color. In the animation mode it can be observed directly at the screen how the tokens and/or tasks in the current process move and change.

• Petri nets with attributed knots and connectors
   
• Modular nets for a clear structure
   
• Smalltalk extensions for modeling and simulation
   
• Grafical input/output
   
• Freely programmable interfaces to other programs
   
• Extensive libraries for statistics, optimization and fuzzy logic