Analyzing conflicts in non-functional requirements is a major task in large software systems development projects. Many of the non-functional requirements that accumulate vary over time. Systems analysts often maintain non-functional requirements incrementally. Requirement information overload and employee turnover problems may complicate conflict detection in the non-functional requirement evolution process. This work proposes a conflict detector in non-functional requirement evolution (CDNFRE) system that uses ontologies as a theoretical foundation for automatically detecting conflicts. Requirement metadata and conflict detection rules and their associated requirement generation and conflict detection processes are proposed for the CDNFRE mechanism. A prototype is developed. A case study of electronic commerce in a television station company demonstrates the feasibility and effectiveness of the proposed CDNFRE system. 
CDNFRE: Conflict detector in non-functional requirement evolution based on ontologies