Model-based system development

Reactive systems, i.e. systems reacting to events in their environment, base their operation on models of the objects of interest in the environment. In the current practice these models are implemented as algorithms ultimately relating observations to actions. This approach results in systems that are rather inflexible and sometimes difficult to maintain. In addition, the different uses made of the various models easily results in built-in inconsistencies, leading to undesirable systems behaviour. An alternative approach is sketched in this short paper in which models are represented explicitly in the system