Early modeling and validation of timed system requirements using Timed Use Case Maps

There is a general consensus on the importance of good requirements engineering for achieving high-quality software. Functional requirements capture the intended behavior of the system in terms of services, tasks, or functions the system is required to perform, while non-functional requirements capture required properties of the system, such as timing, performance, and security. These non-functional requirements play a crucial role during system development life cycle serving as selection criteria for choosing among myriads of design decisions. The ability to model and validate the system non-functional properties at the requirements level supports the detection of design errors during the early stages of a software development life cycle and helps reduce the cost of later redesign activities. The widespread interest in time modeling and analysis techniques at the requirements phase provides the major motivation for this research. This paper presents a novel and fully automated approach to describe and validate high-level timed requirements using the Timed Use Case Maps language. We extend the, ITU-T standard User Requirements Notation, Use Case Maps metamodel with time requirements. The resulting extensions are implemented within the jUCMNav tool and formalized using Abstract State Machines allowing for automated simulation and analysis. We illustrate the applicability of our approach using a business process model (conference review process model) and a real-time system model (IP multicast routing case study).