24 (271)

Some charactcrs of Petri nets:

1.    Formalism for modeling aigorithms strongly affects comprchcnsion of the underlying algorithmic idea and the capability to analyzc the modcłs.

2.    Features ofPNs:

a)    Petri Nets employ the most elementary concepts of States and transitions

(actions preserved Information; i.e. from action and result of its occurrence the previous State can be recomputed (this supports analysis techniąue)

b)    Petri Nets emphasize locality of causality and its effect (graphicai representation represents this yicinity of locality) -> using arrows.

c)    Petri Netss explicitly represent fundamenta! issues of distributed Systems (atomicity, synchronization, mutual independence of actions, messages, and shared memory)

(Remarie: contro! flow, variables, and assignment statement are not present in Petri Nets) -these can be however extracted through simulation of a Petri net

d)    Petri Nets are neither state-based nor action-based: both States and actions have a particular status

e)    Petri Nets are unstructured by definition. Structure can be put on them additionally.

f)    Petri Nets models are implementable and are neutral against specific implementation languages (this is because of features d) and e)).