Bisimulation as a verification and validation technique for message sequence charts

Abstract

The complexity of determining whether a system meets the requirements of its designers has increased with the widespread use of real time concurrent systems. This testing process has however been simplified with the emergence of Formal Description Techniques. FDTs not only provide the means for formally specifying a system, but also supply the theoretical basis for conformance testing. One such FDT is Message Sequence Charts(MSCs). MSCs have evolved out of the need to describe the inter-process flow of communication in a concise, easily understood, graphical format. MSCs originally took the form of system traces, but with the development of, and additions to the specification, the 1996 MSC specification now provides a comprehensive description technique. An FDT is of little use, unless it can be used in the validation and verification of a system specification. In the case of MSCs, this has usually involved the testing of a trace against a specification. Formal specification with MSCs has however provided the opportunity of testing the equivalence of MSC specifications.