Effective and Efficient Modeling and Simulation with DEVS Variants

The modular design of Discrete Event System Specification (DEVS) models—each communicates with its environment via input and output ports—allows the construction of complex models by composition. The efficient modeling with DEVS, based on certain formalisms or on model composition, is one important aspect of using DEVS in practice. The chapter discusses some variants of DEVS and thereby focus on formalisms for variable structure models. The abstract sequential algorithm is pretty close to the abstract threaded simulator. There is still an explicit coordinator, respectively, an explicit simulator per model entity. The flat sequential simulator virtually flattens a hierarchical DEVS model, so that it can be computed with a single simulation algorithm in a very efficient manner. Distributed simulation requires partitioning and load balancing techniques to complement the basic algorithms. The DynPDEVS defines inputs, outputs, and states as structured sets.