Feature Refinement

Abstract

Development by formal stepwise refinement offers a guarantee that an implementation satisfies a specification. But refinement is frequently defined in such a restrictive way as to disallow some useful development steps. Here we define feature refinement to overcome some limitations of refinement and show its usefulness by applying it to examples taken from the literature.Using partial relations as a canonical state-based semantics and labelled transition systems as a canonical event-based semantics, we define functions formally linking the state-and event-based operational semantics. We can then use this link to move notions of refinement between the event-and state-based worlds.An advantage of this abstract approach is that it is not restricted to a specific syntax or even a specific interpretation of the operational semantics

Contexts, refinement and determinism

“…As an example we defined vertical refinement from a "handshake layer" to a "broadcast layer", and elsewhere (e.g. [27,28]) we have shown how the design step of adding error handling or new events can be described formally. This formalisation between handshake and broadcast layers brings out different assumptions made about determinism and this issue has had to be addressed too.…”