1 Petri Nets III Wednesday, October 26, 2005

2 Review -Timed Petri Net  Time can be associate with places, arcs, or transitions. There are real life examples where time is associated with more than one type of petri net parts. Generally(in this course), we’ll associate time with each transitions.  This delay time can be deterministic or probabilistic.  Number of servers produce different outcomes. D i = A i + σ Timed Petri Net with Multi-Server / Infinite Server D i = A i + σ D i = max(D i-1, A i ) + σ Timed Petri Net with a Single Server D i = max(D i-1, A i ) + σ

3 Clarification p 1 p 2 t 1 t 2 Not a conflict After a firing, p 1 and p both are going to get a token each. Conflict t 1 and t 2 are both ready to fire but the firing of one of them leads to disabling of the other transitions.

4 Exercises Draw and simulate fig Draw and simulate following situation: John and Mary are sharing one toy between them. John plays with the toy and then hands it to Mary. Meanwhile, John may pick up another series of toys, but each time he is unable to give a toy to Mary until she tells him she finished with the toy, and can now get the next one.