A Product Automaton Formalism for Hierarchical, Modular, Discrete Simulation

A formalism for discrete simulation allows one to specify a discrete simulation model in an unambiguous, mathematically precise manner. The DEVSM formalism, developed by B. Zeigler, is a well-known example. In this paper, we present a formalism that is very much related to the DEVSM formalism, the PA formalism. The most significant difference between the two approaches is the world view adopted by each of the formalisms. In the DEVSM case, components experience internal and external state transitions. Interaction is accomplished by the sending of signals from component to component; basically, a network view of the world. The PA formalism views the world as a hierarchy of components, each of which can experience conditional and unconditional state transitions. Interaction between components is accomplished through the coordinated passing of inputs down the hierarchy, an intrinsically top-down view of the world.

INFORMS Journal on Computing, ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.