An Introduction to Modeling and Simulation with (Python(P))DEVS

Discrete Event System Specification (DEVS) is a popular formalism for modeling complex dynamic systems using a discrete-event abstraction. At this abstraction level, a timed sequence of "events" input to a system cause instantaneous changes to the state of the system. Main advantages of DEVS are its rigorous formal definition, and its support for modular composition. This updated tutorial from the WSC'18 tutorial "Discrete Event System Specification Modeling and Simulation" introduces the Classic DEVS formalism in a bottom-up fashion, using a traffic light example. The syntax and operational semantics of Atomic (i.e., non-hierarchical) models are introduced first. Coupled (i.e., hierarchical) models are introduced to structure and couple Atomic models. We continue to actual applications of DEVS, e.g. in performance analysis of queueing systems. All examples are presented with the tool PythonPDEVS, though this introduction is applicable to others. We conclude with further reading on DEVS theory, DEVS variants, and DEVS tools.