GDEVS: a generalized discrete event specification for accurate modeling of dynamic systems

Given a process whose output is a dynamic function of time, the traditional discrete event specification (DEVS) approximates the input, output, and state trajectories through piecewise constant segments, where the segments correspond to discrete time intervals that are not necessarily equal in length. For processes that defy accurate modeling through piecewise constant segments, this paper presents GDEVS, a generalized discrete event specification, wherein the trajectories are organized through piecewise polynomial segments. The utilization of arbitrary polynomial functions for segments promises higher accuracies in modeling continuous processes as discrete event abstractions. In general, discrete event systems including DEVS and GDEVS execute faster on host computers because executions occur corresponding to significant changes in the system unlike in continuous simulations where execution is on a continuous basis. GDEVS´ superiority over DEVS lies in its ability to discretize a system characteristic. A key contribution of GDEVS is that it permits the development of a uniform simulation environment for hybrid, i.e. both continuous and discrete, systems. GDEVS is illustrated for a first order system and a hybrid system, with piecewise linear segments. Two representative systems have been modeled under GDEVS and executed on a simulator developed for GDEVS