Evaluating consistency between BPEL specifications and functional requirements of complex computing systems using the NFR approach

Complex computing systems are usually composed of several subsystems interacting with each other. The functional requirements of the system being developed can be captured by BPEL (Business Process Execution Language) specifications, which are obtained from UML (Unified Modeling Language) diagrams. The captured BPEL specifications can be simulated in an environment such as NetBeans. The functional requirements of a complex system are known to change throughout the development due to changes in client´s needs. Consistency between the BPEL specifications and the functional requirements is important to ensure that the system developed based on BPEL specifications satisfies the client´s needs. In this paper we employ the NFR Approach, where NFR stands for non-functional requirements, to evaluate this consistency. We apply this approach to an example complex system, namely, the elevator control system, by first listing the functional requirements, capturing the requirements in BPEL, and evaluating the consistency between them using the NFR Approach. Based on this evaluation we are able to determine changes needed to BPEL specifications to match the functional requirements, justify the reasons for changes to the BPEL, and keep historical record of changes performed to the specifications during the system development process. It is our belief that practitioners in both industry and academia will find the NFR Approach to consistency evaluation a significant aid during complex systems development.