Refactoring Real-time Specifications

This paper presents an approach to refactoring real-time specifications written using Real-Time Object-Z. This allows implementation components such as clocks and sensors, not necessarily present in an initial abstract specification, to be introduced via a sequence of refinement steps. The approach, based on similar work for Object-Z, is enabled by a semantics of object instantiation and operation synchronisation introduced in this paper. Means of refining synchronising operations to reflect the timing and causality constraints of an implementation are also presented.