Hybrid Approximations of Markovian Petri Nets

A Markovian Petri net is a stochastic discrete event system (DES) frequently used for analysis and performance evaluation purposes. In the past, the fluidification has been proposed in different DES's as a relaxation technique for avoiding the “state explosion problem”. Following the same approach, in this paper a hybrid Petri net model is defined as a partial relaxation of an original Markovian Petri net. It is shown through a simple example that such partial relaxation can be worse than a full relaxation (given by a fully continuous Petri net). Therefore, the rest of the paper is devoted to obtain sufficient conditions for guaranteeing the approximation of the hybrid Petri net model to the original discrete system.