Class and Capsule Refinement in UML for Real Time

We propose refinement laws for the top level design elements of Real Time UML (UML-RT): classes and capsules. These laws can be used to develop concrete design models from abstract analysis models. Laws for introducing and decomposing classes and capsules are presented. Standard data refinement techniques are adapted for classes, and process refinement techniques for capsules. We also propose techniques for behavioural inheritance of classes and capsules. Soundness is briefly addressed by relating UML-RT elements to OhCircus, a formal unified language of classes and processes. To illustrate the overall strategy, we develop a detailed design of an operating system resource scheduler from a high-level analysis model.