AN ABSTRACT OF THE DISSERTATION OF Kerry R. Poppa for the degree of Doctor of Philosophy in Mechanical Engineering presented on August 22, 2001 Title: Theory and Application of Vector Space Similarity Measures in Computer Assisted Conceptual Design Abstract approved: Robert B. Stone Irem Y. Tumer A number of computational tools now exist to aid in developing conceptual solutions based on a functional description of a design problem. A key limitation of these tools is the way results are organized for presentation to the user. In general, results are an undifferentiated mass of potential solutions. Analysis using a novel concept clustering tool shows concept generator output represents permutations of a set of a few solution archetypes. This provides an initial solution to organizing and presenting the results. More efficient solutions are sought by adopting a generate-evaluate-guide framework from the computational design synthesis literature. Specifically, the concept generation approach is altered so that each generated solution maximizes the variety it adds to the set of solutions. To achieve this, suitable similarity measures must first be developed. Current techniques for similarity assessment in the design literature tend to be ad hoc and highly specialized to particular tasks. Prior work from the field of information retrieval is applied and extended to create a generalized approach to similarity assessment for vector space design data. These techniques are validated against an existing design by analogy methodology. A new tool for locating functional analogies within a database of existing products is developed as a result. Improved similarity measures are combined with the proposed computational synthesis framework from literature to modify an existing concept generation tool. The resulting tool efficiently locates the few novel solutions in the set of possible results, and is a key step in the continued evolution of this class of computational design tools. !Copyright by Kerry R. Poppa August 22, 2011 All Rights Reserved Theory and Application of Vector Space Similarity Measures in Computer Assisted Conceptual Design by Kerry R. Poppa A DISSERTATION submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosopy Presented August 22, 2011 Commencement June 2012 Doctor of Philosophy dissertation of Kerry R. Poppa Presented on August 22, 2011. APPROVED: Co-Major Professor, representing Mechanical Engineering Co-Major Professor, representing Mechanical Engineering Head of the School of Mechanical, Industrial, and Manufacturing Engineering Dean of the Graduate School I understand that my dissertation will become part of the permanent collection of Oregon State University Libraries. My signature below authorizes release of my dissertation to any reader upon request. Kerry R. Poppa, Author ACKNOWLEDGEMENTS I would like to express my sincere appreciation to my co-advisors Dr. Rob Stone and Dr. Irem Tumer for their guidance, support, and advice during my graduate studies. I am indebted to my committee for their time, patience, and thoughtful feedback. This work has been influenced by collaborations with kind and helpful colleagues from a number of other institutions. Their feedback and insights have molded my thinking over the years, and I am in their debt. While working on this dissertation I was supported by funds from the National Science Foundation (CMMI-0742677, IIS-0841379, and CMMI- 0927745), Oregon State University Mechanical Engineering Fellowships, and the G&E Lundstrom Scholarship. Any opinions, findings and conclusions or recommendations expressed are mine and do not reflect the views of any of these funding sources. TABLE OF CONTENTS Page 1! INTRODUCTION AND BACKGROUND .................................................................. 1! 1.1! INTRODUCTION .......................................................................................................... 1! 1.1.1 Roadmap ................................................................................................................. 1! 1.1.2 Contributions of This Chapter ............................................................................ 2! 1.2! MOTIVATION AND RESEARCH QUESTIONS ............................................................. 2! 1.3! ORGANIZATION OF THIS DISSERTATION ................................................................. 4! 1.4! BACKGROUND ............................................................................................................ 6! 1.4.1 Structured Design Methods ................................................................................. 6! 1.4.2 Design Repositories ............................................................................................... 8! 1.4.3 Functional Basis and Component Taxonomies ................................................ 9! 1.4.4 Computational Design Synthesis ...................................................................... 11! 1.5! CONCLUSION ............................................................................................................ 15! 2! SORTING AUTOMATED CONCEPT GENERATOR OUTPUT .......................... 16! 2.1! INTRODUCTION ........................................................................................................ 16! 2.1.1 Roadmap ............................................................................................................... 16! 2.1.2 Contributions of This Chapter .......................................................................... 17! 2.2! CONCEPT PARAMETER BASED SORTING ................................................................ 17! 2.2.1 Outline of Proposed Method ............................................................................. 18! 2.2.2 Estimating Concept Parameters from Repository Data ................................. 20! 2.2.3 Sample Implementation 1: Design for Manufacture and Assembly ............ 23! 2.2.4 Sample Implementation 2: Estimating Data for Environmental Impact Assessment .................................................................................................................... 31! 2.2.5 Conclusions about Parameter Estimation Based Sorting .............................. 33! 2.3! SORTING BASED ON COMPONENT SELECTION ...................................................... 34! 2.3.1 Cluster Analysis ................................................................................................... 36! 2.3.2 Variable Reduction Via Principal Component Analysis ............................... 37! 2.3.3 Case Studies of Component Based Clustering ................................................ 38! TABLE OF CONTENTS (Continued) Page 2.3.4 Conclusions on Component Based Sorting Through Clustering and PCA 47! 2.4! CONCLUSIONS .......................................................................................................... 48! 3! FUNCTIONAL ANALOGY IN DESIGN ................................................................... 50! 3.1! INTRODUCTION ........................................................................................................ 50! 3.1.1 Roadmap ............................................................................................................... 50! 3.1.2 Contributions of this Chapter ........................................................................... 51! 3.2! MEASURES OF ANALOGY IN DESIGN ....................................................................... 51! 3.3! APPLICATION OF THE CURRENT MEASURE TO INTER- PRODUCT FUNCTIONAL SIMILARITY .......................................................................................................................... 53! 3.3.1 The Method of McAdams and Wood .............................................................. 53! Application to Data in the Design Repository .......................................................... 57! 3.4! CONCLUSION ............................................................................................................ 67! 4! A UNIVERSAL APPROACH TO VECTOR SPACE SIMILARITY MEASUREMENT IN ENGINEERING DESIGN ............................................................. 68! 4.1! INTRODUCTION ........................................................................................................ 68! 4.1.1 Chapter Roadmap ............................................................................................... 68! 4.1.2 Contributions of this chapter ............................................................................ 69! 4.2! VECTOR SPACE REPRESENTATIONS ........................................................................ 69! 4.3! VECTOR SPACE TECHNIQUES IN INFORMATION RETRIEVAL .............................. 76! 4.3.1 History of Vector Space Models in Information Retrieval ............................ 76! 4.3.2 Latent Semantic Indexing and Rank Reduced Approximations .................. 80! 4.3.3 Constructing the Vector Space Model ............................................................. 82! 4.3.4 Weighting Schemes ............................................................................................. 83! 4.3.5 Reduced Rank Approximations ........................................................................ 86! 4.3.6 An Example: Text Book Title Similarity .......................................................... 96! 4.4! EXPLORING INTER-PRODUCT FUNCTIONAL SIMILARITY THROUGH THE TECHNIQUES OF LSI ........................................................................................................