A modular method for global system behaviour specification

The challenge addressed in this paper is how can we specify the global behaviour of distributed reactive systems in a way which eases the comprehension of the system without compromising its specification´s correctness, completeness, modularity and readability. Instead of defining the global behaviour models in a monolithic way, we approach the problem by decomposing the specification into interface functionality and core functionality. The resulting interface-modular method for system specification is presented and discussed in this paper using a TaxiCentral as case study. The novelty of this method lies in the clear separation of interfaces from core functionality in global specification, and the use of activity diagrams in combination with collaborations to express and compose the specifications.