Prototype-oriented representation of engineering design knowledge

Abstract

In this paper we present arguments concerning the nature of inheritance hierarchies for representing the relationships between computing objects which encapsulate engineering design knowledge. We review and criticize some other options among object-oriented languages and knowledge representation systems for creating inheritance hierarchies. These are languages and systems which support the relatively rigid class/instance model of property sharing and use a support environment for modification and change. By contrast we provide coupling between objects which employs a scheme of property inheritance that uses ‘exemplary’ or prototypical objects. Our approach yields a class-free inheritance system, in the tradition presented in the literature or the Actor languages, that enables design concepts to emerge easily as the user describes and modifies them at the keyboard. Our prototype-oriented approach offers a means of continually replicating design concepts through object refinement: this principle of one object being specified as a refinement of another object is specialization . We show that treating a knowledge base as evolutionary encourages exploratory comparisons and supports its customization for design representation. We use single taxonomic inheritance to demonstrate the effectiveness of representing information which originates from different perspectives (distinguished structurally as separate inheritance subhierarchies which allow a design world of discourse consisting of many ad hoc groupings to evolve) and criticize the use of multiple inheritance for knowledge representation.