效绵鼎 Petri nets-Motivation In contrast to state machines,state transitions in Petri nets are asynchronous.The ordering of transitions is partly uncoordinated;it is specified by a partial order. Therefore,Petri nets can be used to model concurrent distributed systems. Many flavors of Petri nets are in use,e.g. 0 Activity charts(UML) o Data flow graphs and marked graphs 7Petri nets-Motivation ◼ In contrast to state machines, state transitions in Petri nets are asynchronous. The ordering of transitions is partly uncoordinated; it is specified by a partial order. ◼ Therefore, Petri nets can be used to model concurrent distributed systems. ◼ Many flavors of Petri nets are in use, e.g.  Activity charts(UML)  Data flow graphs and marked graphs 7