Stochastic timed event graphs : bounds, cycle time reachability and marking optimization

This paper addresses the performance evaluation and optimization of stochastic timed event graphs. The transitions firing times of such a timed event graph are random variables with general distribution. We first establish an upper bound and a lower bound for the average cycle time of the timed event graph. We prove that any cycle time greater than the greatest mean transition firing time can be reached by putting enough tokens in each place. The necessary and sufficient condition of the reachability of the greatest mean firing time is established. We then address the marking optimization problem which consists in obtaining a given cycle time while minimizing a linear criterion depending on the initial marking