REQUIREMENTS

A formal requirements specification
Formal specifications are mathematically based techniques whose purpose are to help with the implementation of systems and software. They are used to describe a system, to analyze its behaviour, and to aid in its design by verifying key properties of interest through rigorous and effective reasoning tools.

As formal methods are increasingly used in the development of industrial-scale software systems, there is a growing awareness of the need to integrate formal notations with existing structured software development methods. To make requirements analysis both comprehensible and rigorous, a formal requirements specification method is proposed that combines and extends DeMarco data flow diagrams with the Vienna development method.

The specifications produced using this method have good readability, a wellde signed structuring mechanism, and precise semantics. This article details work toward development of a verified analysis approach based on the concept of consistency checking for guaranteeing the correctness of analysis steps.