Formalizing requirements in formal specifications usually requires high skills for abstraction and experience in using the formal notation in which the specification is written. This poses a challenge to many practitioners who have to deal with realistic systems within the required schedule and budget. To handle this challenge, a pattern system has been proposed for computer-aided construction of formal expressions. It organizes various inter-related patterns on computer, each of which deals with the formalization of a kind of informal ideas. But how to represent such knowledge to facilitate its automatic utilization and maintenance remains a problem. This paper presents an approach to representing and utilizing the pattern knowledge on the basis of a formal definition of the pattern system. The application process of the pattern system is described in HFSM (Hierarchical Finite State Machine) and treated as knowledge. By performing a proposed algorithm, necessary information can be retrieved from the HFSM for capturing informal requirements and automatically generating formal expressions. We also describe a prototype tool that implements the approach and present a case study on modeling a bank data management system.
展开▼
