Supporting Reusability in a System Design
Environment by Case-Based Reasoning Techniques 

Herbert Praehofer and Josef Kerschbaummayr

Johannes Kepler University Linz
Department of Systems Theory and Information Technology
A-4040 Linz, Austria
{hp | kj}@cast.uni-linz.ac.at



Abstract. 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 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 scheme for case retrieval
and structural similarities and has adapted usual similarity measures to compute
degree of fulfillment of requirements. It has been show by different example
projects that the developed methods can be of great practical assistance for a designer.
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