Yentl Van Tendeloo, Hans Vangheluwe
2018 2018 Winter Simulation Conference (WSC)  
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 pertinent "events" input to a system (or internal timeouts) 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 tutorial introduces the Classic DEVS formalism in a bottom-up fashion, using a simple
more » ... ing a simple 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, for example in performance analysis of queueing systems. All examples are presented with the tool PythonPDEVS, though this introduction is equally applicable to other DEVS tools. We conclude with further reading on DEVS theory, DEVS variants, and DEVS tools. 162 978-1-5386-6572-5/18/$31.00 ©2018 IEEE Van Tendeloo and Vangheluwe simulation time input simulation time state simulation time output Yellow Red Green Red 60s Yellow 3s Green 57s e=0 Van Tendeloo and Vangheluwe S, q init , δ int ,ta S = {GREEN, YELLOW, RED} q init = (GREEN, 0.0) δ int = {GREEN → YELLOW, YELLOW → RED, RED → GREEN} ta = {GREEN → 57, YELLOW → 3, RED → 60} from pypdevs.DEVS import *
doi:10.1109/wsc.2018.8632372 dblp:conf/wsc/TendelooV18 fatcat:4l6kvxv77fafncyv6fxx7le75e