Requirements engineering and verification using specification animation

Presents an overview of the Possum specification animation system and its integration into the Cogito methodology and toolset. Possum allows interpretation (or animation) of specifications written in Sum, the specification language of Cogito. We distinguish two potential uses for Possum and illustrate each of these with an example. The first is the use of Possum for specification verification, where the analysis of properties of specifications by the specification designer is emphasised. The second use is specification validation, where the specification is checked against the informal requirements of the system.