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Abstract:
Subject of this work are strict cyclic discrete event systems. Within strict cyclic processes events of a system recur with constant cycle time T. Scheduling of such systems, that means the determination of the time of occurrence for all events, primarily aims minimisation of cycle time under utilisation of existing degrees of freedom in choice of a sequence of events. Thereby events e.g. describe start and end of activities, that are processed on shared resources. Within this work a new modeling method for this class of systems is created under utilisation of the particularly suited Max-Plus algebra. The resulting model contains so called sequence modules. Within a sequence module, sequence alternatives of activities of one resource can be presented in a cohesive way. Sequences of activities are coded with combinations of integer variables q, that can be interpreted as orders of edges in a graph. So the scheduling problem can be represented by the search for the optimal combination of q-values. From the analytical description, extensive in equalities for the values of q are derived, which further limit the search domain. A systematical search method allows the globally optimal solution of the optimisation problem.