Real-time Constraints through the ProCoS Layers

. The Provably Correct Systems project [5,6] developed links between layers of formal specifications for real-time systems. These layers cover requirements capture, design, programming and code generation. In this paper we trace real-time constraints through the layers in order to inspect their changing forms. They originate in constraints on continuous dynamical models of physical phenomena. However, in a digital system it is desirable to abstract the complexities of these models to simple clocks, and further to events in a reactive system. This paradigm is the main topic of this paper. We illustrate the different forms of timing constraints in duration calculus, a real-time interval logic. Keywords: embedded system, hybrid system, real-time, requirements, design, formal specification. 1 Introduction When the Provably Correct Systems (ProCoS) project was near its completion, the Lyngby team, who was responsible for case-studies and requirements, received a very long mail ..