a four-way framework for validating a specification
The validation of a software specification may be viewed as a function of what the specification is to be used for and any comprehensive validation exercise needs to address possibly conflicting requirements. In this paper we develop a framework which embodies a 4-way validation strategy to develop and measure a specification against requirements from users, the application domain, restrictions in the notation and language and finally the operational system, obtained through appropriate refinement. Our framework is modelled on Boehm's spiral model and at each iteration of the spiral, the specification is validated in line with the evolving requirements of each of the above four aspects. The process continues until convergence is reached and no further amendments are made to the specification during a subsequent iteration. For each of the four aspects, a sequence of processes is defined to facilitate the validation of the specification from the viewpoint presented by the relevant aspect. The utility of our framework is illustrated through a case study in Object Z.
validation requirements spiral model formal specification