Research On Requirements Modeling Based On MSC

With the rapid development of software technology, the scope expanding of the software application, the ambassador scale of software system, and the function of software is becoming more complex, the requirements analysis are becoming more difficult. This shows that the requirements analysis is an extremely important stage in software life cycle. The good demand not only helps to avoid or eliminate the early error for the development of software development, but also can reduce the cost, improve the software quality. In software engineering field, how to effectively capture users demand has become a research focus.Scenario is an effective tool which can extraction, documentation and verification requirements. The Behavioral Modeling Technology based on the formal and non formal scene has gradually been widely used in requirements engineering. In the design and analysis which based on scenario, the requirements of users are composed by several local Scenarios, and each of the scenarios describes system requirement clips. However using the traditional non-formal method to describe the scenarios can cause the final demand hard to correct and complete, and user demands that described by multiple scenarios is likely to exist overlap. So, how to describe scenarios more accurately, how to analyze and modeling the repetitive behaviors, and how to produce a more complete global system behavior model through mergers the behavior model described by these local scenarios, is the main research contents of this paper.In this paper, we propose a formal requirements elicitation and the method of behavioral modeling, according to the theory of categories. By adopting Category theory to model, using the message sequence chart to describe the scenarios.We firstly give a category structure for Message Sequence Charts, and its instance, message and events etc are described, just as making MSC components objectivity, which focus on studying the interaction between the systems. This enhances its description and function expansion flexibility. Categories composed by objects and the mapping between objects, which pays great attention to study the morphisms and composition. Through the functor, pan shot, the limit and so on, some original vague notion can be accurately described. The method based on mathematics used for describing need rules can avoid semantic ambiguity, and describes the user scenarios more accurately.Then, the paper proposes a kind of algorithm to merger scenario fragments and validation to complete the requirements behavioral modeling based on Category structured MSC, which removes repetitive and exception scenarios. We give a merger algorithm for several category structured MSCs using universal constructions in category theory. In the consolidated method, emphasizing expected scene and excepted scenarios that user submits for input to merger local scenarios gradually. During the merger, we effectively go besides repeating and exception scenarios. And the algorithm supports added scenarios. Then, we produce a more complete global system behavior model through mergers the behavior model described by these local scenarios. Finally, we take a simplified SMS information service system as an example, and introduce requirements modeling process based on MSC in detail. The research explicitly demonstrates that it is feasible and effective for requirements modeling based on MSC.