Implementing Standard Examples with NSA-DEVS

Abstract

To utilize the PDEVS formalism for the practical modeling and simulation of discrete-event systems, the recently proposed variant NSA-DEVS combines the Mealy behaviour of RPDEVS with a simple simulator algorithm by employing infinitesimal time delays. To further test the practical usefulness of this new approach, four simple systems showing non-trivial event-cascades are modeled and simulated within a concrete NSA-DEVS

Modeling and Simulation of a Real-world Application using NSA-DEVS

“…A standard library of atomic components has been built for the models described in [7] and the production line, containing mathematical and routing components, simple source and sink components and several lo gis SNE 33(4) -12/2023 Substructure of the furnace components in Fig. 1.…”

“…Several of them have been described in [7], among them an atomic model ToWorkspace that can be connected to an output port and copies the incoming values to a global output variable, which can be analysed after the simulation run. For the modeling of the furnace a batch component has been added that combines a given num-ber of incoming entities into one batch entity, together with a corresponding unbatch atomic model.…”

“…All these values are usually predefined and set to the value τ de f = ε. From the analysis of a few example models in [7] the following situations have been identified, where one has to change some of the parameters from their default value: a.) Input events that appear during the input delay time of a component, overwrite a previous input value at the same port, which sometimes is useful, but more often not.…”

“…An open question from [6,7] was, whether one needs port specific input delay times. The answer after this study is a definitive "no": In all examples the default value of the input delay was sufficient for all input ports to get a reasonable model.…”

“…But instead of introducing a plethora of small delay parameters, NSA-DEVS uses infinitesimal time delays. Therefore it defines t ime v alues a s elements of the hyperreals * R, which is a mathematically welldefined field extension of R containing an infinitesimal ε > 0 [5] The definition o f a s imulator [ 6] a nd t he careful analysis of a set of standard examples [7] have shown the basic soundness of the new formalism. But to prove its general applicability, one has to test it with a large non-trivial example.…”