Adding temporal modeling to the UML to support systems design

The UML has been proposed as a suitable modeling language for systems engineering. There are questions, however, regarding the language's suitability. For example, the interfaces between heterogeneous systems must be precisely defined during design, and the completeness and precision of that definition is heavily dependent on the modelling language used. This article contends that the UML in its current form is insufficient for this purpose because it has no provision for the analysis of complex time-based interactions typical of such an interface. The solution proposed here is to translate the UML models that define those interfaces into a formal method. This translation can be automated, therefore "hiding" the formalism from the user, but still providing the analytical benefits. The formal method used is the Q-model. This is a mathematically based computational model used primarily in the design of time-critical systems and includes support for sophisticated temporal analysis.