Knowledge-Based Computer-Aided Design: The Computer as Design Partner

Abstract

Design can be defined as a process of searching for a physical or organizational schema which, when realized, will achieve certain goals and abide by certain constraints. This process, which is usually applied in complex situations, is characterized by creative thinking and judgment. These two high-level functions are facilitated by representational and analytical functions, which keep track of the emerging schema and provide specific quantitative and qualitative measures of its expected performance.

In this paper it is suggested that computers could assist in the creative and judgmental functions of design if they had access to knowledge and experience similar to that which designers rely upon. This knowledge can be represented and stored in the form of performance criteria, goals, and design plans. Such assistance does not necessitate that all steps in the design process be computer-aided. Some design operations should continue to be performed by the designer, while others are best performed by the computer. The dynamic allocation of tasks between the designer and the computer will enable a more flexible approach to design computability, particularly in responding to changing requirements, unforeseen problems, and emerging opportunities, as they arise during the design process.

A methodology, and its PROLOG implementation, for developing knowledge-based computerized design assistants is presented. This proposed methodology differs from other approaches to the employment of computers in the creative and judgmental functions of design in its scope and flexibility: it spans all phases of the design process, and incorporates knowledge-acquisition facilities which enable the system’s knowledge-base to be dynamically expanded and modified.

We believe that computer-aided design systems modeled after this methodology represent an improved adaptation of computers for assisting in the design of physical artifacts; therefore, they may lead to a better realization of the promise CAD holds for improving designers’ productivity and product quality.