Adopting Case Modeling Study Support The Evolution Of The Form

Nowadays software systems need to evolve continuously to meet the frequent changes of its external environment and the requirements of its users, software evolution has been one of the most important forms of the entire life cycle of software systems. Therefor, the theoretical research of software evolution and requirements engineering will gain benefit if we give consideration to the evolution of software systems from the beginning of software requirements analysis. The use-case model is one important product of requirements engineering, while the complexity of its granularity has been perplexing software engineers for years. This dissertation aims to providing a method to make the action of use-case modeling more effective and more efficient, for this purpose, four main progress have been made in this dissertation.Firstly, a formal, multi-level use cases model is proposed, which is composed of three typical use-case model: function use-case model, system use-case model and business use-case model. The function use-case model is formalized by Hoare Logic, the system use-case model consists of two or more function use cases following some compostion rules, and the business use-case model is formalized by a Petri net while the relation between the system use cases in a business use case is discussed.Secondly, after analyzing the feedback mechanism in the activity of function use case modeling, a set of updating operation of the function use-case model is proposed, and the necessary condition of updating function use cases through feedback is given.Thirdly, after analyzing the feedback mechanism in the activity of system use case modeling, the essence of updating system use cases through feedback is analyzed, an operation set which includes transformation and extension of the function use cases sequence in a system use case is proposed as well.Fourthly, after analyzing the feedback mechanism in the activity of business use case modeling, the essence of updating business use cases is analyzed, an operation set which includes adjusment of the relation between the system use cases, the addition of a new system use case, the deletion and replacement of an existing system use case is proposed as well.In summary, this dissertation proposes a formalized, multi-level use cases model that chan help control the granularity of use cases and support the evolution in requirements engineering.