Development of external design assistance procedures for product design expert systems

In product design, the designer must draw upon many types of information including both product-user requirements and design developments in related fields. The application of expert systems in product design problems will help designers to systematically consider relevant design information and make the most effective use of the time they devote to the design process.;In order to enhance the efficiency of expert systems in solving product design problems, this research develops external design assistance procedures which employ a design matrix representation and the component design strategy in the generation and evaluation of feasible design alternatives. The external procedures are developed in conjunction with a ball point pen design expert system to demonstrate the applicability of the procedures.;Two approaches, a heuristic search approach and a random assignment approach, are used in the development of the design assistance procedures. The two approaches do not differ significantly in quality of design recommendations, but the heuristic search approach requires far less processing time to reach a design recommendation. In the development of a design recommendation with either approach, a confidence interval for order statistics is used to determine if enough unique feasible design alternatives have been generated.;Finally, an analysis is made concerning the number of rules required to construct an expert system using two hypothetical frameworks for the ball point pen design expert system. The results indicate that the product design expert system incorporating external procedures uses fewer rules than does a conventional rule-based expert system.