An Abstract Approach to Describing Scenario-Based Specifications

Scenarios have been shown to be very helpful for requirements elicitation. However, they only capture partial behaviors of interaction among system component instances, and system behaviors are modeled by sequences of events. Such a behavioral model only captures parallel composition without synchronization in the sense that all the sequences of events are generated in an interleaving semantics. In this paper, we introduce a time model which is a category of time domains. We provide a trajectory model for the sequence of events. A trajectory describes precisely which events occur along the points of its time domain and show that categorial products allow us to compute parallel composition of behaviors with synchronization constraints. Our approach is helpful for broadening research vision of software engineering.