Techniques for the Parametrization of Discrete-Event System Templates

Abstract

Two techniques for the parametrization of templates in the template design methodology are introduced. First, the use of finite-state automata extended with variables is demonstrated. This kind of parametrization allows one to vary the occurrences of events by varying a parameter. Second, a new way of parametrizing templates is proposed, named compositional parametrization. With this technique, a template consists of the composition of a number of structurally identical components whose events are indexed differently, depending on a parameter. This kind of parametrization allows one to vary the structure and event set of the template by varying a parameter. An enhancement of compositional parametrization with the use of special selector transitions is also discussed. This extension allows one to model interactions between components which depend on the total number of components in a composition and thus cannot be modelled by simple parametrization of event indices. With the choice of a specific parameter, regular finite-state automaton models are obtainable from the templates parametrized with any of the aforementioned techniques. Thus, such parametrized templates can be easily introduced in the template design modelling environment and they integrate seamlessly with the supervisory control framework. Motivating examples to illustrate the application of template parametrization are provided.