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Minimum Potential Energy Designs. Bradley Jones & Christopher Gotwalt SAS Institute Inc. Abstract. Introducing a new class of space filling designs based on a physical analogy of design points as protons connected by springs. Properties Spherical symmetry Nearly orthogonal
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Minimum Potential Energy Designs Bradley Jones & Christopher Gotwalt SAS Institute Inc.
Abstract • Introducing a new class of space filling designs based on a physical analogy of design points as protons connected by springs. • Properties • Spherical symmetry • Nearly orthogonal • Uniform Spacing • Easy to compute with unconstrained optimization code • Outline • Show how to generate these designs • Discuss their properties • Give examples with different numbers of factors & sample sizes
Objective function where dij is the distance between the ith and jth points. Goal: Find the design that minimizes the above function
Near Orthogonal 12 Factor 24 Run Design
Estimation Efficiency for Low Order Polynomial Models D-Efficiency for full quadratic model. Four and five factor designs have an added center point.
Conclusions • Benefits • Spherical symmetry • Nearly orthogonal • Uniform Spacing • Available in commercial software • Negative • Not “space filling” in higher dimensions (except in low dimensional projections.
Contact Information Bradley.Jones@jmp.com