Applying specification methods to complex systems

A critical study of DFD based specification methods is proposed. The considered methods are the SA-RT method and the SC-AC (state charts and activity charts) method; these methods are a representative sample of the most used methods in reactive systems design. The first contribution is to show practitioners the main differences between the two methods. The second contribution is on the use of SA-RT guidelines and design rules for state charts, and various mechanisms are proposed. This work is tested on two CASE tools: Teamwork, for SA-RT; and Statemate, for SC-AC. The temporal semantics of DFD methods are unsatisfactory for expressing timing constraints; the third contribution is to the improvements required to the existing methods with respect to timing constraints and formalisation