Use of Semi-Formal and Formal Methods in Requirement Engineering of ILMS

Abstract

A systematic approach in requirement engineering helps in discovering and understanding the requirements at different levels of abstraction as well as makes the requirements traceable and verifiable early in the project. This paper presents a methodology for requirement engineering by using a combination of formal and semiformal techniques to model software requirements for analysis and verification. The proposed framework incorporates requirement-analysis and requirement-verification models, which are guided by the Domain Model represented by a Conceptual Class diagram and the defined Ontology. The proposed approach is particularly useful when requirements are defined in hierarchical levels of abstraction and traceability between a requirement at a detailed level and its correspondence at an abstract level is required. The proposed framework also allows verification of the accordance of the requirements with respect to the Domain Model. The requirement analysis model at each level of abstraction is represented by a combination of three different modeling techniques: Conceptual Graph, Use-Case diagram and VDM-SL specification. A verification model to ensure traceability between the requirements at different abstraction levels, using a three-dimensional schema, is also proposed. The Requirements of an Intelligent Learning Management System are used as an example to illustrate the proposal.