# Center for Computing Research (CCR)

# Center for Computing Research

### Scott A. Mitchell

Scott A. MitchellComputational Mathematics Email: samitch@sandia.govPhone: 505/845-7594Fax: 505/844-4728Mailing address:Sandia National Laboratories P.O. Box 5800, MS 1320 Albuquerque, NM 87185-1320 |

I am currently doing technical work related to mesh generation and improvement. I've been working on the Cubit project lately; the mathematics of simultaneously good primal and dual meshes; and Voronoi crust surface reconstruction. My main areas of interest are mesh generation, computational geometry, computer science, and discrete math,

I've worked on sampling, uncertainty quantification and high dimensional space exploration, and information theory. Some concluded projects include desiging a MANET protocol, researching validation process guidelines of computer models of how humans think, low-bandwidth authentication, and a military logistics siumlator called CoreSim. For a while I dabbled in computational topology, "forecasting" (uncertainty, statistics, and graph algorithms) over large-scale informatics graphs; and statistical techniques for finding the root-cause of faults in networked computer systems. Some information projects included data-streaming algorithms, e.g. approximate counting; and the geometry of distance functions for comparing probability distributions in information theory.

I've researched some sample based techniques, including their uses for mesh generation, integration, and uncertainty quantification. Often I consider uniform-random point sampllngs with inter-sample inhibition distances and guaranteed domain coverage, and meshes from these point sets. These Poisson-disk samplings are popular in computer graphics, for integration-like problems such as texture synthesis, and in simulation for fracture mechanics, where non-randomness would spoil the outcome. There are some radial line-search generalizations of point-sampling. These find use for uncertainty quantification and optimization, often in high-dimensions.

For my full page, including publications, see http://www.cs.sandia.gov/~samitch/

### Education/Background

I received a B.S in Applied Math, Engineering & Physics from the University of Wisconsin-Madison in 1988. I received an M.S. (1991) and Ph.D. (1993) in Applied Math from Cornell University. I worked the summer of 1991 at Xerox PARC with Marshall Bern and John Gilbert. Since Oct 1992 I've been at Sandia National Laboratories. I researched triangular and tetrahedral meshing algorithms via a computational geometry approach from 1992-1993. I was part of the Cubit project, doing mesh generation R&D from 1993-2000, and project leadership from 2000-2002. I did things like researching algorithms and existence proofs for hexahedral meshes and optimization for assigning the right number of edges locally so the model can be meshed globally. I managed the Optimization and Uncertainty Estimation department from 2002-2007. I served in various capacities on various programs, including LDRD (internal research program) and NNSA's ASC program. I decided I missed building things and figuring things out for myself and moved on to technical work in 2007. After some informatics projects, I gravitated back to geometry and mesh generation. I've done some disk-packing meshes and geometric approaches to optimization and uncertainty quantification since 2011. Much of my work since 2007 is described above.