Despite the effectiveness of requirements formalization in producing accurate requirements documentation and deepening the developers\u27 understanding of the envisioned systems, this technique can hardly be accepted by software industry mainly because it requires mathematical sophistication and considerable experience in using formal notations, which remains a challenge to many practitioners. Many methods and tools have been proposed to deal with the problem by providing general guidance or automatic support in transforming informal requirements into formal specifications. However, they fail to accomplish the task when encountering incompleteness and ambiguities in the informal requirements. To handle this challenge, this thesis describes a pattern-based approach to facilitating the formalization of requirements. In this approach, a specification pattern system is pre-defined to guide requirements formalization where each pattern provides a specific solution for formalizing one kind of function into a formal specification. All of the patterns are classified and organized into a hierarchical structure according to the functions they can be used for formalization. The distinct characteristic of our approach is that all of the patterns are stored on computer as knowledge for creating effective guidance to facilitate the developer in requirements formalization; they are "understood" only by the computer but transparent to the developer. Based on the pattern system, a method that guides the requirements formalization process by applying the pattern system is described. To facilitate the understanding of the guidance produced by the pattern system and the utilization and maintenance of the pattern knowledge, a method for representing the pattern system is proposed where attribute tree and HFSM are adopted. These two notations are used to represent different parts of the pattern knowledge. The method for applying the pattern knowledge represented in the two notations is given. We also describe a prototype tool that supports the pattern-based approach. The tool derives necessary functional details of the intended requirement through interactions with the developer and generates a formal specification according to the obtained information. Two experiments on the tool supported approach are presented to demonstrate the effectiveness of the approach.博士(理学)法政大学 (Hosei University
