Experience using formal methods for capturing requirements of web-based applications

The current practice in capturing requirements of web-based applications is accomplished by an ad-hoc and informal manner. In this paper we investigate the use of formal methods to formalize the requirements of a web-based application. We have used a simple yet powerful Definitional Specification Language (DSL) for this task. DSL is based on first order predicate calculus, and has three main concepts: a resource, a transitional, and a state type. These concepts help in specifying dynamic behaviors and the resultant specification is clear with no cumbersome manipulation of time variables. A brief description of DSL is given before we provide the informal requirements of our web-based application. We formalize the requirements using DSL and describe how this is done. We conclude that the benefits gained with such formalization have made the development clear and minimized the cycle of fix-and-test.