A Study On Modeling Software Requirements Based On Scenario & Formal Method

The Information Age is upon us. Information Technology (IT) industry is expanding the world's economy at an exponential rate. The current challenge is whether software system of high quality can be provided at a rate that keeps up with users' needs and at competitive prices. Experiences in developing software indicate that precise understanding of user requirements is the key to the successful creation of a new software system. This thesis focuses on the problem of modeling user requirements. The leading instructional ideology in this thesis is that software requirement must truly reflect the users' needs. By so doing,scenario is adopted to capture user requirements in the early phase and documented with Specification and Description Language (SDL) in the later phase. Thus,uSe formal requirement specification paves the way to the success of the software system under development.The following topics are discussed in this diesis:(1) Modeling software requirement. Scenario is used in this thesis to capture user requirements and specified by Use Case Maps and use case.(2) Formalizing user requirements. Based on the global scenarios specified by Use Case Maps and MSC,a formal SDL-based specification of software requirements can be derived from the maps.(3) Validation and verification of formal requirements specification. Tools supporting SDL are the main ways adopted to validate and verify the requirement specification.The main contributions of this thesis are presenting a UCM & SDL based method to model software requirement,discussing the process in detail and describing the requirements of a small real-time system (Automated Teller Machine,ATM). The problems raised by diis thesis's discussion include combining the method and the UML modeling language and further research on case study on a large scale.