Generalized discrete event simulation of dynamic systems

Given a process whose output is a dynamic function of time, the traditional discrete event abstraction approximates the input, output, and state trajectories through piecewise constant segments. 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 that, in turn, permit faster execution on host computers in contrast to continuous simulations. 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. For complex systems that employ hierarchical descriptions, the need to interconnect models at different levels of abstraction gives rise to the issue of coupled models in GDEVS. This paper introduces the notion of a coupled model and illustrates with examples of GDEVS simulations of continuous systems.