Scenario-based requirements analysis techniques for real-time software systems: a comparative evaluation

Abstract

One of the most critical phases of software engineering is requirements elicitation and analysis. Success in a software project is influenced by the quality of requirements and their associated analysis since their outputs contribute to higher level design and verification decisions. Real-time software systems are event driven and contain temporal and resource limitation constraints. Natural-language-based specification and analysis of such systems are then limited to identifying functional and non-functional elements only. In order to design an architecture, or to be able to test and verify these systems, a comprehensive understanding of dependencies, concurrency, response times, and resource usage are necessary. Scenario-based analysis techniques provide a way to decompose requirements to understand the said attributes of real-time systems. However they are in themselves inadequate for providing support for all real-time attributes. This paper discusses and evaluates the suitability of certain scenario-based models in a real-time software environment and then proposes an approach, called timed automata, that constructs a formalised view of scenarios that generate timed specifications. This approach represents the operational view of scenarios with the support of a formal representation that is needed for real-time systems. Our results indicate that models with notations and semantic support for representing temporal and resource usage of scenario provide a better analysis domain.