SCI Publications
2001
P. Lindstrom, V. Pascucci.
“Visualization of Large Terrains Made Easy,” In Proceedings of the 12th Annual IEEE Conference on Visualization (VIS-01), San Diego, CA, Note: UCRL-JC-144753, IEEE Computer Society, pp. 363--370, 574. October 21-26, 2001.
Y. Livnat, C.D. Hansen, S.G. Parker, C.R. Johnson.
“Isosurface extraction for large-scale datasets,” In Proceedings of Scientific Visualization -Dagstuhl`2000, Edited by F. Post, 2001.
P. Lorenzen, S. Joshi, G. Gerig, E. Bullitt.
“Tumor-Induced Structural Radiometric Asymmetry in Brain Images,” In Workshop on Mathematical Methods in Biomedical Image Analysis (MMBIA), pp. 163--170. 2001, 2001.
K. Ma, S.G. Parker.
“Massively Parallel Software Rendering for Visualizing Large-Scale DataSets,” In IEEE Trans. Vis & Comp. Graph., pp. 72--83. July/August, 2001.
R.S. MacLeod, B. Yilmaz, B. Taccardi, B.B. Punske, Y. Serina, D.H. Brooks.
“Direct and Inverse Methods for Cardiac Mapping Using Multielectrode Catheter Measurements,” In Journal of Biomedizinische Technik, Vol. 46(supp), pp. 207--209. 2001.
R.S. MacLeod, B.B. Punske, B. Yilmaz, S. Shome, B. Taccardi.
“The Role of Heart Rate in Myocardial Ischemia From Restricted Coronary Perfusion,” In J. Electrocardiol., Vol. 34 (supp), Note: ISCE conference paper, pp. 43--51. 2001.
J. McCorquodale, J.D. de St. Germain, S.G. Parker, C.R. Johnson.
“The Uintah Parallelism Infrastructure: A Performance Evaluation on the SGI Origin 2000,” In Proceedings of The 5th International Conference on High-Performance Computing, Seattle, Mar, 2001.
S. Mendez, J.G. Curro, M. Putz, D. Bedrov, G.D. Smith.
“An Integral Equation Theory for Polymer Solutions: Explicit Inclusion of the Solvent Molecules,” In Journal of Chemical Physics, Vol. 115, No. 12, pp. 5669--5678. 2001.
DOI: 10.1063/1.1397333
Self-consistent Polymer Reference Interaction Site Model (PRISM) calculations and molecular dynamics (MD) simulations were performed on athermal solutions of linear polymers. Unlike most previous treatments of polymer solutions, we explicitly included the solvent molecules. The polymers were modeled as tangent site chains and the solvent molecules were taken to be spherical sites having the same intermolecular potential as the polymer sites. The PRISM theory was solved self-consistently for both the single chain structure and intermolecular correlations as a function of chain length and concentration. The rms end-to-end distance from PRISM theory was found to be in agreement with corresponding MD simulations, and exhibited molecular weight dependence in accordance with scaling predictions in the dilute and concentrated solution limits. The presence of explicit solvent molecules had a significant effect on the packing of the polymer by inducing additional structure in the intermolecular radial distribution function between polymer sites. Using the direct correlation functions from the athermal solution and the random phase approximation, we were able to estimate the spinodal curves for solutions when polymer and solvent attractions were turned on. We found significant deviations from Flory-Huggins theory that are likely due to compressibility and nonrandom mixing effects.
M. Miller, C. Moulding, J. Dongarra, C.R. Johnson.
“Grid-enabling Problem Solving Environments: A Case Study of SCIRun and Netsolv,” In Proceedings of The 5th International Conference on High-Performance Computing, 2001 Advanced Simulation Technologies Conference, Society for Modeling and Simulation International, pp. 98--103. April, 2001.
V. Pascucci, R.J. Frank.
“Global Static Indexing for Real-time Exploration of Very Large Regular Grids,” In Proceedings of Supercomputing 2001, Note: UCRL-JC-144754, ACM, Nov, 2001.
V. Pascucci.
“On the Topology of the Level Sets of a Scalar Field,” In Proceedings of the 13th Canadian Conference on Computational Geometry, Note: UCRL-JC-142262, pp. 141--144. August, 2001.
M. Pernice, M.D. Tocci.
“A Multigrid-Preconditioned Newton-Krylov Method for the Incompressible Navier-Stokes Equations,” In SIAM Journal on Scientific Computing, Vol. 23, No. 2, pp. 398--418. 2001.
DOI: 10.1137/S1064827500372250
Globalized inexact Newton methods are well suited for solving large-scale systems of nonlinear equations. When combined with a Krylov iterative method, an explicit Jacobian is never needed, and the resulting matrix-free Newton--Krylov method greatly simplifies application of the method to complex problems. Despite asymptotically superlinear rates of convergence, the overall efficiency of a Newton--Krylov solver is determined by the preconditioner. High-quality preconditioners can be constructed from methods that incorporate problem-specific information, and for the incompressible Navier--Stokes equations, classical pressure-correction methods such as SIMPLE and SIMPLER fulfill this requirement. A preconditioner is constructed by using these pressure-correction methods as smoothers in a linear multigrid procedure. The effectiveness of the resulting Newton--Krylov-multigrid method is demonstrated on benchmark incompressible flow problems.
J.D. Peterson, S. Vyazovkin, C.A. Wight.
“Kinetics of the Thermal and Thermooxidative Degradation of Polystyrene, Polyethylene and Poly(propylene),” In Macromolecular Chemistry and Physics, Vol. 202, No. 6, pp. 775--784. March, 2001.
DOI: 10.1002/1521-3935(20010301)202:63.0.CO;2-G
The thermal degradations of polystyrene (PS), polyethylene (PE), and poly(propylene) (PP) have been studied in both inert nitrogen and air atmospheres by using thermogravimetry and differential scanning calorimetry. The model-free isoconversional method has been employed to calculate activation energies as a function of the extent of degradation. The obtained dependencies are interpreted in terms of degradation mechanisms. Under nitrogen, the thermal degradation of polymers follows a random scission pathway that has an activation energy ≈200 kJ·mol–1 for PS and 240 and 250 kJ·mol–1 for PE and PP, respectively. Lower values (≈150 kJ·mol–1) are observed for the initial stages of the thermal degradation of PE and PS; this suggests that degradation is initiated at weak links. In air, the thermoxidative degradation occurs via a pathway that involves decomposition of polymer peroxide and exhibits an activation energy of 125 kJ·mol–1 for PS and 80 and 90 kJ·mol–1, for PE and PP respectively.
H. Pfister, B. Lorensen, C. Bajaj, G. Kindlmann, W. Schroeder, L.S. Avila, K.M. Raghu, R. Machiraju, J. Lee.
“The transfer function bake-off,” In IEEE Computer Graphics and Applications, Vol. 21, No. 1, IEEE, pp. 16--22. 2001.
DOI: 10.1109/38.920623
S. Pizer, S. Joshi, P.T. Fletcher, M. Styner, G. Tracton, Z. Chen.
“Segmentation of Single-Figure Objects by Deformable M-reps,” In Medical Image Computing and Computer-Assisted Intervention (MICCAI), Edited by WJ Niessen and MA Viergever, New York, pp. 862--871. October, 2001.
O. Portniaguine, D.M. Weinstein, C.R. Johnson.
“Focusing Inversion of Electroencephalography and Magnetoencephalography Data,” In 3rd International Symposium On Noninvasive Functional Source Imaging, Journal of Biomedizinische Technik (special issue), Vol. 46, Innsbruck, Austria pp. 115--117. Sep, 2001.
R. Rawat, S.G. Parker, P.J. Smith, C.R. Johnson.
“Parallelization and Integration of Fire Simulations in the Uintah PSE,” In Proceedings of the Tenth SIAM Conference on Parallel Processing for Scientific Computing, Portsmouth, Virginia, March 12-14, 2001.
E. Reinhard, P. Shirley, C.D. Hansen.
“Parallel point reprojection,” In Proceedings of the IEEE 2001 symposium on parallel and large-data visualization and graphics, pp. 29--35. 2001.
DOI: 10.1109/PVGS.2001.964400
Improvements in hardware have recently made interactive ray tracing practical for some applications. However, when the scene complexity or rendering algorithm cost is high, the frame rate is too low in practice. Researchers have attempted to solve this problem by caching results from ray tracing and using these results in multiple frames via reprojection. However, the reprojection can become too slow when the number of samples that are reused is high, so previous systems have been limited to small images or a sparse set of computed pixels. To overcome this problem we introduce techniques to perform this reprojection in a scalable fashion on multiple processors.
L.M. Schultz, C.R. Butson, G.A. Clark.
“Post-light potentiation at type B to A photoreceptor connections in Hermissenda,” In Neurobiology of Learning and Memory, Vol. 76, No. 1, pp. 7--32. July, 2001.
A. Shamir, V. Pascucci.
“Temporal and Spatial Level of Details for Dynamic Meshes,” In Proceedings of the ACM Symposium on Virtual Reality Software and Technology 2001, Banff Center, Canada, ACM, November, 2001.