Case-based reasoning techniques to support reusability in a requirement engineering and system design tool

CASA (computer aided systems architecting) is a methodology and tool to support the design of complex technical systems. It combines approaches from systems and requirement engineering and AI. System design in CASA is requirement-driven, and works by a hierarchical stepwise top-down refinement of designs and a hierarchical decision-making process. One important task in CASA deals with the reusability of existing design artifacts and is supported by case-based reasoning techniques. Based on given structural specifications and formal requirements, a search procedure finds the best inexact match in a design base and computes an estimated degree of fulfillment for requirements. The approach employs efficient graph-matching and indexing schemes for case retrieval and structural similarities, and has adapted usual similarity measures to compute degree of fulfillment of requirements. It has been shown by different sample projects that the developed methods can be of great practical assistance to a designer.