Performance evaluation as a tool for evaluating the formal design of interactive system

This paper aims at presenting how performance evaluation of models can be used within the design process of interactive systems. We demonstrate how the use of a formal task model may enhance the design of interactive systems, by providing quantitative results on which designers may base their decisions. We also demonstrate that it is possible to describe both task and system models within the same formal framework. We propose a software design life cycle integrating formal task and system modelling. The approach is illustrated by a toy example which, despite its small size, allows us to develops both task and system models and to perform two iterations on the life cycle. The device and tasks are modelled using the Interactive Cooperative Objects (ICO) formalism, which is based on Petri nets and on the object-oriented approach..