Utilizing Event-B for domain engineering: a critical analysis

This paper presents our experience of modeling land transportation domain in the formal framework of Event-B. Well-specified requirements are crucial for good software design; they depend on the understanding of the domain. Thus, domain engineering becomes an essential activity. The possibility to have a formal model of a domain, consistent with the use of formal methods for developing critical software working within it, is an important issue. Safety-critical domains, like transportation, exhibit interesting features, such as high levels of nondeterminism, complex interactions, stringent safety properties, and multifaceted timing attributes. The formal representation of these features is a challenging task. We explore the possibility of utilizing Event-B as a domain engineering tool. We discuss the problems we faced during this exercise and how we tackled them. Special attention is devoted to the issue of the validation of the model, in particular with a technique based on the animation of specifications. Event-B is mature enough to be an effective tool to model domains except in some areas, temporal properties mainly, where more work is still needed.