Dealing with Non - Functional Requirements : Three Experimental Studies of a Process - Oriented

Quality characteristics are vital for the success of software systems. To remedy the problems inherent in ad hoc development, a framework has been developed to deal with non-functional requirements (quality requirements or NFRs). This framework takes the premise that the quality of a product depends on the quality of the process that leads from high-level NFRs to the product. The purpose of this paper is to give an initial evaluation of a recently proposed framework for dealing with non-functional requirements, by way of three studies of small portions of three information systems. These systems have a variety of characteristics , reeecting a variety of real application domains. This paper attempts to evaluate the extent to which the framework's objectives are met, namely, representing NFR-speciic requirements, considering design trade-oos, relating design decisions to NFRs, justifying the decisions, and assisting defect detection. The studies deal with and analyse three important classes of non-functional requirements for systems, namely, accuracy , security, and performance. The studies provide preliminary support for the usefulness of certain aspects of the framework, while raising some open issues. Some of the results have been reviewed by people with a knowledge of the kinds of organisations whose systems were studied.