Extending FCD Process to Support COTS Selection

In large software system, components depend on each other and should not be evaluated individually. This paper proposes a new process for multiple COTS selection based on extension of a proven system decomposition technique FCD. During the process of decomposition, local requirements are allocated into functional modules as local evaluation criteria for COTS candidates while crosscutting requirements are considered later in global selection. Due to the hierarchical structure of FCD, COTS products with varying granularities are considered. COTS candidates are evaluated through analyzing the gap between COTS features and requirements and fitness score is calculated based on the gap and adjustment cost which are measured by function points. Those COTS products with fitness score higher than a pre-defined threshold keep going into the global selection phase. In global selection, combinations of candidate COTS products for modules are evaluated based on crosscutting requirements.