Soheil Afraz - Faculty of Computer and Information Technology Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran
Hassan Rashidi - Department of Mathematics and Computer Science, AllamehTabataba&#۰۳۹;i University, Tehran, Iran
Nasser Mikaeilvand - Department of Mathematics, Ardabil Branch, Islamic Azad University, Ardabil, Iran

Requirement engineering is one of the critical phases in the software development process. Functional Requirements (FR) and Non-Functional Requirements(NFR) are two of the fundamental requirements in software projects that are observed in the classifications of most researchers in the software engineering field. Conflicting and overlapping among the requirements in both intra and extra communications levels are one of the main challenges in the elicitation and prioritization phases. This paper presents a decision strategy to respond to this challenge called requirements conflicts management strategy (RCMS). This strategy is defined to manage conflict and overlap of NFRs in the prioritization of the constraints satisfaction model for requirements prioritization, known as "CSOP + RP" model, to which the necessary constraints are applied. RCMS is applied to the "CSOP+RP" model as a pre-processing phase by the requirement analyzer and the results are delivered to the system manager. RCMS is founded on several components: the conflicts catalog among NFRs, the mapping model of NFRs to the domain of software systems, and the calculation of Pearson correlation coefficients in NFRs. The negative, positive, and zero values of the correlation coefficients are calculated on the importance of the requirements, which mean conflict, overlap and neutral, respectively. RCMS was implemented on Police Command-and-Control System(PCCS) as a designed case study with specific NFRs and FRs. Therefore, the statistical analysis of the experimental results shows that the proposed strategy increases the accuracy of the input values of the prioritization model and better decision-making in managing conflicts and controlling overlaps. Furthermore, RCMS help to reduce the ambiguities between NFRs and FRs and also influences of NFRs in requirement ranking by the search-based prioritization approach.

Conflicts Management, Functional Requirements, non-functional requirements, Overlapping control, Prioritization model, Pearson correlation coefficients, strategy