Design of user-driven interfaces using petri nets and objects

Abstract

This paper presents a survey of three formalisms that are used for modelling the dialogue of user-driven interfaces: state diagrams, events and Petri nets. Petri nets are found to be the best suited formalism in this area, even if they lack structure. In order to address this problem, the usefulness of the object-oriented approach is discussed, and we present a formalism, called Petri Nets with Objects (PNO), that integrates both object-oriented and Petri nets approaches. A three-step method for building such models, consisting in defining the object classes, definiting the presentation and modelling the application’s dialogue, is presented, and a detailed example illustrates the application of this method. Finally, we present an overview of the benefits that can be expected from the use of the PNO formalism in dialogue modelling.