“…During the last years several dynamic production models have been developed either describing the trajectory of each good through the network, which is called discrete event simulation [2], or by using so-called fluid models models, where averaged quantities are used to track goods, see [1-4, 7, 9, 13] for an overview. Based on these continuous production models, optimization problems have been introduced [8,10,11,14]. These models typically deal with economic issues such as minimization of costs or maximization of output and allow for the interpretation of optimal routing of goods through a manufacturing system, best possible production mix or optimal order policies.…”