Animating Event B Models by Formal Data Models

Abstract

We present a formal approach allowing to animate event B formal models. Invariants, deadlock freeness properties are expressed and proved on these models. This paper presents an approach that suggests to complete the proof activity in the event B method by animation activity. The obtained animator may be used to check if the event B models obtained fulfill user requirements, or to provide a help to the developer when describing its formal event B models and particularly in defining event B invariants and guards. More precisely, event B models are translated into data models expressed in the EXPRESS formal data modeling technique. The obtained data models are instantiated and provide an animation of the original B models. Following this approach, it becomes possible to trigger event B models, which themselves trigger entity instantiation on the EXPRESS side. As a further step, we show that the B models can be used as a monitoring system raising alarms in case of incorrect systems behavior. The proposed approach is operationally implemented in the B2EXPRESS tool which handles animation of event B models. It has been experimented for the validation of multimodal human interfaces in the context of VERBATIM project.