Non-functional requirements analysis modeling for software product lines

In most IT projects, software developers usually pay attention to functional requirements that satisfy business needs of the system. Non-functional requirements (NFR) such as performance, usability, security, etc. are usually handled ad-hoc during the system testing phase, when it is late and costly to fix problems. Due to the importance and criticality of NFR, I study the problem of modeling NFR for Software Product Lines (SPL), which adds yet an additional dimension of complexity. This paper will survey the software engineering literature, in search of a systematic way to analyze and design NFR, from the perspectives of the concept of commonality and variability of SPL and the characteristics of NFR. Finally, I will propose a methodology based on the extension of Product Line UML-Based Software Engineering (PLUS) techniques, for a unified and automated method to model NFR throughout all phases of SPL engineering.