Validation of Function Pruning Rules Through Similarity at Three Levels of Abstraction

Abstract

Function modeling is often used in the conceptual design phase as an approach to capture a form-independent purpose of a product. Previous research uses a repository of reverse-engineered function models to support conceptual-based design tools, such as similarity and design-by-analogy. These models, however, are created at a different level of abstraction than models created in conceptual design for new products. In this paper, a set of pruning rules is developed to generate an abstract, conceptual-level model from a reverse-engineered function model. The conceptual-level models are compared to two additional levels of abstraction that are available in a design repository. The abstract models developed through the pruning rules are tested using a similarity metric to understand their usefulness in conceptual design. The similarity of 128 products is computed using the Functional Basis controlled vocabulary and a matrix-based similarity metric at each level of abstraction. A matrix-based clustering algorithm is then applied to the similarity results to identify groups of similar products. A subset of these products is studied to further compare the three levels of abstraction and to validate the pruning rules. It is shown that the pruning rules are able to convert reverse-engineered function models to conceptual-level models, better supporting design-by-analogy, a conceptual-stage design activity.