Evaluation of the functional basis using an information theoretic approach

Chiradeep Sen Graduate Student [email protected] Benjamin W. Caldwell Graduate Student [email protected] Joshua D. Summers 1 Associate Professor [email protected] Gregory M. Mocko Assistant Professor [email protected] Department of Mechanical Engineering, Clemson University, Clemson SC 29634-0921 Abstract A metric for computing information content of function models in mechanical engineering design is proposed. Function models are graph-based representations used to describe the functionality of engineered artifacts, where the nodes are function verbs and the edges are the objects of action, respectively. The Functional Basis, a controlled vocabulary of these verbs and nouns organized in a three level hierarchy, is intended to support consistent representation of function models. The Design Repository is a web-based archive of function models of consumer products described with the Functional Basis. This paper presents the theoretical underpinnings of a metric for information content of function models, the assumptions required to support it, the definitions of key terms associated with it, and its practical interpretation. Finally, the metric is used to study the usefulness of the Functional Basis through a series of experiments on function models within the Design Repository. The results of the experiment indicate that the secondary level of the Functional Basis is the most beneficial to designers, both in terms of information content and information density.