Papers & Reports 2003

The purpose of this study is to evaluate the feasibility of remote memory access (RMA) programming on shared memory parallel computers. We discuss different RMA based implementations of selected CFD application benchmark kernels and compare them to corresponding message passing based codes.
Performance Evaluation of Remote Memory Access (RMA)Programming on Shared Memory Parallel Computers,NAS Technical Report, NAS-03-001, January 2003.

We describe a benchmark problem, based on the Block-Tridiagonal (BT) problem of the NAS Parallel Benchmarks (NPB), which is used to test the output capabilities of high-performance computing systems, especially parallel system
NAS Parallel Benchmarks I/O Version 2.4,NAS Technical Report, NAS-03-002, January 2003.

Preconditioning methods have become the method of choice for the solution of flowfields involving the simultaneous presence of low Mach number flow and transonic flow regions. In this paper, we describe the implementation of the preconditioned dual-time methodology in the OVERFLOW code.
Implementation of Preconditioned Dual-Time Procedures in OVERFLOW,AIAA 41st Aerospace Sciences Meeting and Exhibit, Reno, NV, January 6-9, 2003.

Markets are often considered superior to other global scheduling mechanisms for distributed computing systems. This paper describes why such beliefs in markets are not warranted. It does so by examining the general equilibrium theory, in terms of scope, abstraction, and interpretation.
Applicability of Markets to Global Scheduling in Grids,NAS Technical Report, NAS-03-004, February 2003.

Data movement across computational grids and across memory hierarchy of individual grid machines is known to be a limiting factor for application involving large data sets. In this paper we introduce the Data Cube Operator on an Arithmetic Data Set which we call Arithmetic Data Cube (ADC).
Arithmetic Data Cube as a Data Intensive Benchmark,NAS Technical Report, NAS-03-005, February 2003.

The purpose of the work reported on is two-fold: The optimization of large-scale earth science applications and the evaluation of the use of automatic parallelization tools. We have applied the CAPO computer aided parallelization tool developed at the NASA Ames Research Center to the Goddard Cumulus Ensemble (GCE) cloud modeling code
Experience on the Parallelization of a Cloud Modeling Code Using Computer-Aided Tools,NAS Technical Report, NAS-03-006, March 2003.

The multi-block overset grid method is a powerful technique for high-fidelity computational fluid dynamics (CFD) simulations about complex aerospace configurations. In this paper, we present three different load balancing strategies for overset grids and analyze their effects on the parallel efficiency of a Navier-Stokes CFD application running on an SGI Origin2000 machine.
Load Balancing Strategies for Multi-Block Overset Grid Applications,NAS Technical Report, NAS-03-007, March 2003.

The overset grid methodology has significantly reduced time-to-solution of high-fidelity computational fluid dynamics (CFD) simulations about complex aerospace configurations. This paper analyzes the effects of various performance enhancement techniques on the parallel efficiency of an overset grid Navier-Stokes CFD application running on an SGI Origin2000 machine.
An Analysis of Performance Enhancement Techniques for Overset Grid Applications,NAS Technical Report, NAS-03-008, March 2003.

We present arguments in favor of developing an Open Source option for NASA software; in particular we discuss how Open Source is compatible with NASA’s mission. We compare and contrast several of the leading Open Source licenses, and propose one for use by NASA.
Developing An Open Source Option for NASA Software,NAS Technical Report, NAS-03-009, April 2003.

We describe an extension of the NAS Parallel Benchmarks (NPB) suite that involves solving the application benchmarks LU, BT and SP on collections of loosely coupled discretization meshes. The solutions on the meshes are updated independently, but after each time step they exchange boundary value information
NAS Parallel Benchmarks, Multi-Zone Versions,NAS Technical Report, NAS-03-010, July 2003.

The overset grid methodology has significantly reduced time-to-solution of highfidelity computational fluid dynamics (CFD) simulations about complex aerospace configurations. This paper analyzes the effects of various performance enhancement strategies on the parallel efficiency of an overset grid Navier-Stokes CFD application running on an SGI Origin2000 machine.
Performance Enhancement Strategies for Multi-Block Overset Grid CFD Applications,NAS Technical Report, NAS-03-011, September 2003.

The theory of elliptic curves is a classical topic in many branches of algebra and number theory, but recently it is receiving more attention in cryptography. Part I of this survey gives a modest overview of how elliptic curves have been applied to public key cryptography. The objective is to introduce a bridge between the mathematical facts of elliptic curves and its application for cryptography.
A Survey of Elliptic Curve Cryptosystems, Part I: Introductory,NAS Technical Report, NAS-03-012, August 2003.

Using the intersubband semiconductor Bloch equations for a two-conduction-subband model, we show that intersubband absorption spectra for narrow wells are dominated by the Fermi-edge singularity (via coupling to repellons) when the electron gas becomes degenerate and in the presence of large nonparabolicity.
Many-Body Effects on Intersubband Resonances in Narrow InAs/AlSb Quantum Wells,NAS Technical Report, NAS-03-013, August 2003.

In this work, we show how automatic relative debugging can be used to find differences in computation between a correct serial program and an OpenMP parallel version of that program that does not yield correct results.
Automatic Relative Debugging of OpenMP Programs,NAS Technical Report, NAS-03-014, October 2003.

Navigation or dynamic scheduling of applications on computational grids can be improved through the use of dynamic characterization of grid resources. We use the NAS Grid Benchmarks to map performance of grid resources into a “GridScape” representing the dynamic state of the grid.
Using Grid Benchmarks for Dynamic Scheduling of Grid Applications,NAS Technical Report, NAS-03-015, October 2003.

For efficient use of a computational grid, which includes machines located in a number of sites, we have to be able to estimate data delivery times between the machines. For dynamic distributed grids it is unrealistic to know exact parameters of the communication hardware and the current communication traffic, hence we should rely on a performance model of the network to estimate data delivery times.
Monitoring and Modeling Performance of Communications in Computational Grids,NAS Technical Report, NAS-03-016, November 2003.

Intersubband transitions in semiconductor quantum wells are studied using a density matrix theory that goes beyond the Hartree-Fock approximation by including the full second order electron-electron scattering terms in the polarization equation for the first time.
Collective Excitations in InAs Quantum Well Intersubband Transitions,NAS Technical Report, NAS-03-017, December 2003.

Linear absorption spectra from intersubband resonance in InAs/AlSb quantum wells are analyzed theoretically using the intersubband semiconductor Bloch equation approach. Our model goes beyond the Hartree-Fock approximation and treats particle-particle correlations under the second Born approximation. Electron-electron and -LO phonon scatterings from such a treatment describe intrinsic line broadening to the intersubband resonance.
Microscopic Modeling of Intersubband Resonances in InAs/AlSb Quantum Wells,NAS Technical Report, NAS-03-018, November 2003.

Clusters of SMP (Symmetric Multi-Processors) nodes provide support for a wide range of parallel programming paradigms. In this study we compare the performance of different implementations of the same Computational Fluid Dynamics (CFD) benchmark application, using the same numerical algorithm but employing different programming paradigms.
Comparing the OpenMP, MPI, and Hybrid Programming Paradigms on an SMP Cluster,NAS Technical Report, NAS-03-019, November 2003.

Modern authorization systems span domains of administration, rely on many different authentication sources, and manage complex attributes as part of the authorization process. This paper presents Cardea, a distributed system that facilitates dynamic access control, as a valuable piece of an inter-operable authorization framework.
Cardea: Dynamic Access Control in Distributed Systems,NAS Technical Report, NAS-03-020, November 2003.