A case-based expert system approach for quality design

Quality design in an enterprise is to design the formulation and processing parameters of products in a cost-effective manner so that the resulting properties can meet the quality specifications given by customers. This design problem often lacks the exact formula for predicting quality properties, and highly depends upon human designers' past experiences. This paper presents a case-based expert system approach for developing new product properties that can effectively support all the steps in the design process from storing past cases, through retrieving similar cases, to adapting the retrieved case for the new product. Within this approach. case-based reasoning uses a hierarchical case indexing method for efficient case retrieval, and provides sophisticated similarity metrics for accurate case matching. When there is a discrepancy between the most similar case retrieved and new product, the case-based design process embraces the expert system technique to reconcile the discrepancy by using domain-specific knowledge on the relationships between design parameters and quality properties. Such integration of case-based reasoning and expert system provides a systematic procedure for design engineers to retrieve past cases quickly and accurately, and to effectively accumulate their expertise for design adaptation. (C) 1998 Elsevier Science Ltd. All rights reserved.