Capturing Non-functional Software Requirements Using the User Requirements Notation

Non-functional requirements (NFRs) are crucial software requirements that have be specified early in the software development process while eliciting the functional software requirements (FRs) [1,2]. NFRs can be viewed as additional constraints that have to be satisfied by the functional requirements. The non-satisfaction of NFRs is one of the main reasons for the failure of software projects. Formal specification techniques for describing FRs has been considered excessively in the software literature. Artifacts for developing a Use Case Model using the Unified Modeling Language (UML) are very useful for eliciting FRs [3]. However, the formal specification of NFRs is a current topic of interest in the software community. Formalizing the capture of NFRs would facilitate a formal documentation, validation and testability of NFRs in software systems. The User Requirements Notation (URN) is a standard proposed by the International Telecommunication Union (ITU) [4,5] for the representation of requirements in future telecommunication systems and services and in software systems in general. This paper focuses on NFRs and how to model them using the Goal-Oriented Requirements Language (GRL), a component of URN [6]. We illustrate the use of GRL for the capture of NFRs for mobile agent systems [7, 9, 11]. The GRL diagrams for the NFRs of this system were developed using the Organizational Modeling Environment (OME) tool [8].