Structuring complex requirements

Abstract

Sets of requirements that analysts are dealing with are often big and complex. That makes requirements structuring one of the most important activities in requirements engineering, because of how requirements are structured and presented directly impacts the requirements development process and the quality of requirements. In this methodological paper we argue that a requirements analyst has to build a requirements architecture that fits the properties of the problem. In particular, the requirements analyst should create a clear vision of the principles governing how requirements are being defined, built and presented. We review some of the instruments that an analyst can use to structure requirements: requirements sets, views, levels and links. Among static views we emphasize concepts view , and also consider functions view, application architecture view, and other views; among dynamic views we consider use cases view, operational scenarios view, events view, and others. We specifically notice the importance of individual requirements sets , the purpose of which is to reveal the requirements for a particular element (concept, function, action, etc.). We argue in favor of differentiating between requirements model and requirements representation. We demonstrate on examples how requirements architecture is needed in complex contexts.