Jim Thomas (NASA Langley)
Dr. J. L. Thomas is currently head of the Computational Modeling and Simulation Branch at NASA Langley Research Center. He has worked at NASA Langley since 1971, beginning as a cooperative education student at Virginia Tech. He received a doctoral degree in aerospace engineering from Mississippi State University in 1983 for work related to coupling Euler and inverse boundary layer equations. He was one of the original developers of the CFL3D Reynolds-Averaged Navier-Stokes code. He is a Fellow of the American Institute of Aeronautics and Astronautics. His current responsibilities are the development of aerodynamic and acoustic methods for the analysis and design of large-scale aerospace vehicles.
Abstract: "Emerging Trends in Computational Simulation"
A review of the past and current roles simulation has played in the NASA Aeronautics program is presented. There is an increasing reliance on simulation to supplement theory and ground-based and flight experiments in conducting research into new aerospace vehicles. Examples are given of the current uses of simulation in the NASA Vehicles Systems Program. The bottlenecks in the current systems are examined from the standpoint of how much potential remains to improve the process and fundamental issues that are unresolved. Emerging trends to address the current limitations are addressed.
Chris Johnson (University of Utah)
Professor Johnson directs the Scientific Computing and Imaging Institute at the University of Utah where he is a Distinguished Professor of Computer Science and holds faculty appointments in the Departments of Physics, and Bioengineering. His research interests are in the area of scientific computing. Particular interests include inverse and imaging problems, adaptive methods, problem solving environments, biomedical computing, and scientific visualization. Dr. Johnson founded the SCI research group in 1992 which has since grown to become the SCI Institute employing over 85 faculty, staff and students. Professor Johnson serves on several international journal editorial boards, as well as on advisory boards to several national research centers.
Professor Johnson was awarded a Young Investigator's (FIRST) Award from the NIH in 1992, the NSF National Young Investigator (NYI) Award in 1994, and the NSF Presidential Faculty Fellow (PFF) award from President Clinton in 1995. In 1996 he received a DOE Computational Science Award and in 1997 received the Par Excellence Award from the University of Utah Alumni Association and the Presidential Teaching Scholar Award. In 1999, Professor Johnson was awarded the Governor's Medal for Science and Technology from Governor Michael Leavitt. In 2003 he received the Distinguished Professor Award from the University of Utah.
Solving Environments for Scientific Computing"
In this talk, I discuss our recent research and development of component-based PSEs for large-scale scientific computing problems. Specifically, I will discuss the Uintah, SCIRun, and BioPSE problem solving environments. Uintah is a component-based visual problem solving environment (PSE) that is designed to specifically address the unique problems of massively parallel computation on terascale computing platforms. Uintah supports the entire life cycle of scientific applications (modeling, simulation, and visualization) by allowing scientific programmers to quickly and easily develop new techniques, debug new implementations, and apply known algorithms to solve novel problems. The PSEs I will describe are built on three principles: 1) As much as possible, the complexities of parallel execution should be handled for the scientist, 2) software should be reusable at the component level, and 3) scientists should be able to interact with and visualize their models and simulations both for problem easier set up, as well as their results as the simulation executes. I will give examples of these PSEs applied to several driving applications, including computational combustion, mechanics, fluid dynamics, and medicine.
Prof. Jarek Rossignac
(Georgia Institute of Technology, Atlanta)
Jarek Rossignac is a Full Professor in the
Abstract: “Generation and compression of 3D Meshes for Solid Modeling and Graphics”
Terrain surfaces may be represented as heights sampled over a regular 2D grid. Similarly, scalar fields may be represented by values sampled over a regular 3D lattice. In these cases, the locations of the samples are implicitly defined. Regular sampling usually misses sharp discontinuities and over samples smooth areas. These two drawbacks may be alleviated by the use of irregularly spaced samples. But these also have drawbacks. First, the 3D locations of the samples must be stored. Second, we must specify how the surface or scalar field interpolate the samples. We typically do so through an incidence graph that specifies a triangle mesh for a surface or a tetrahedral mesh for a scalar field. The speaker will first describe his very simple Corner Table and associated operators for storing, traversing, and editing triangle and tetrahedral meshes. Then, he will discuss very simple compression techniques for triangle meshes and tetrahedral meshes and compare them to the compression of regularly spaced models. He will also discuss triangle mesh re-sampling approaches, which replace an irregularly sampled mesh with one whose samples are more regularly distributed and hence can be better predicted and compressed. Then, he will explain how the sharp features that may have been lost during the regular resampling can be automatically restored without further information and how a crude resampled mesh may be smoothened through subdivision while preserving the sharpness of the recovered edges and yet bending them into smooth curves that better approximate the intersections of curved surfaces.
The publications describing these research results and the students and colleagues who have collaborated to their development may be found on the author’s web page.
Yau (Harvard University)
Professor Shing-Tung Yau was awarded a Fields Medal in 1982 for his contributions in the area of geometric partial differential equations, including his solution of the Calabi Conjecture in algebraic geometry, his solution of the Positive Mass Conjecture in general relativity, and his work on real and complex Monge-Ampere equations.
Yau (Harvard University)
In other work Yau constructed minimal surfaces, studied their stability, and made a deep analysis of how they behave in space-time. His work here has implications for the formation of black holes.
Yau's contributions in minimal surfaces also include an important result on the Plateau problem. This problem was posed by Lagrange in 1760 and was studied by Plateau, Weierstrass, Riemann, and Schwarz, but remained open until being solved independently by Douglas and Rado in the late 1920s. However, there were still questions relating to whether Douglas's solution, which was known to be a smooth immersed surface, is actually embedded. Yau, working with W. H. Meeks, solved this problem in 1980.
In their joint paper On the existence of Hermitian Yang-Mills connections in stable bundles (1986), Yau and Karen Uhlenbeck gave a solution of higher-dimensional versions of the Hitchin-Kobayashi conjecture, extending work of Simon Donaldson.
In 1981 Yau was awarded The Oswald Veblen Prize in Geometry, in 1994 the Crafoord Prize of the Royal Swedish Academy of Sciences, and in 1997 the National Medal of Science. He was elected a member of National Academy of Sciences in 1993, and a Foreign Member of the Russian Academy of Sciences in 2003.
of Geometry to Computer Graphics"
We describe a way to organize three dimensional computer graphics using methods of differential geometry and algebraic curve theory. From a large set of points in space, we need to compute the geometry of a surface. We proceed by computing the conformal structure of the surfaces and also all the conformal invariants associated to the surfaces. In particular, we compute their period matrices and related holomorphic quadratic differentials. These are used to identify and reconstruct the surfaces. The method is good for recognition registration and data compression; since the parameterization is global, it is also good for the problem of constructing texture.
Greg N. Frederickson (Department of Computer Science, Purdue University)
Greg N. Frederickson earned an A.B. in Economics from Harvard University in 1969 and a Ph.D. in Computer Science from the University of Maryland in 1977. He is currently a Professor of Computer Science at Purdue University, which he joined in 1982. His area of research is the design and analysis of algorithms, with especial emphasis on graph algorithms and data structures. He has served on the editorial boards of SIAM Journal on Computing, SIAM Journal on Discrete Mathematics, and IEEE Transactions on Computers, and he currently serves on the editorial board of Algorithmica. He has published two books, "Dissections: Plane & Fancy" (1997) and "Hinged Dissections: Swinging & Twisting" (2002). Most recently, he has been trying hard not to fold under pressure as he works to complete a new book, "Piano-Hinged Dissections".
Abstract: "Geometric Dissections Now Swing and Twist"
A geometric dissection is a cutting of a geometric figure into pieces that can be rearranged to form another figure. As visual demonstrations of relationships such as the Pythagorean theorem, dissections have had a surprisingly rich history, reaching back to Persian and Islamic mathematicians a millennium ago and Greek mathematicians more than two millennia ago. Some dissections can be connected with hinges so that the pieces form one figure when swung one way, and form the other figure when swung another way. These dissections have remained as magical as when the English puzzlist Henry Dudeney first exhibited a hinged dissection of an equilateral triangle to a square almost a century ago. Based on my recently published book, "Hinged Dissections" (Cambridge University Press), the talk will explore two fundamental ways to hinge dissections of 2-dimensional figures such as regular polygons and stars. The first way uses "swing hinges", which allow rotation in the plane. The second way relies on "twist hinges", which allow one piece to be turned over relative to another, using rotation by 180 degrees through a third dimension. Both ways give opportunities to employ tessellations and to enjoy various types of symmetry. I will present several techniques for designing both types of dissections and will demonstrate a variety of physical models.