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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Cassini radio and plasma wave investigation - Data compression and scientific applications

The Radio and Plasma Wave Science (RPWS) experiment being built for the Cassini spacecraft will study a wide range of plasma and radio wave phenomena in the magnetosphere of Saturn and will also make valuable measurements during the cruise phase and at other encounters. A feature of data from wave receivers is the capability of producing vastly more data than the spacecraft telemetry link is capable of transmitting back to the Earth. Thus, techniques of on-board data compression and data reduction are important. The RPWS instrument has one processor dedicated to data compression tasks.

Woolliscroft, L. J. C.↗
NASA NTRS1993

Portable computing - A fielded interactive scientific application in a small off-the-shelf package

Experience with the design and implementation of a portable computing system for STS crew-conducted science is discussed. Principal-Investigator-in-a-Box (PI) will help the SLS-2 astronauts perform vestibular (human orientation system) experiments in flight. PI is an interactive system that provides data acquisition and analysis, experiment step rescheduling, and various other forms of reasoning to astronaut users. The hardware architecture of PI consists of a computer and an analog interface box. 'Off-the-shelf' equipment is employed in the system wherever possible in an effort to use widely available tools and then to add custom functionality and application codes to them. Other projects which can help prospective teams to learn more about portable computing in space are also discussed.

Groleau, Nicolas↗
NASA NTRS1993

Cassini radio and plasma wave investigation: Data compression and scientific applications

The Radio and Plasma Wave Science (RPWS) experiment being built for the Cassini spacecraft will study a wide range of plasma and radio wave phenomena in the magnetosphere of Saturn and will also make valuable measurements during the cruise phase and at other encounters. A feature of data from wave receivers is the capability of producing vastly more data than the spacecraft telemetry link is capable of transmitting back to the Earth. Thus, techniques of on-board data compression and data reduction are important. The RPWS instrument has one processor dedicated to data compression tasks.

Woolliscroft, L. J. C.↗
NASA NTRS1995

An Open Simulation System Model for Scientific Applications

A model for a generic and open environment for running multi-code or multi-application simulations - called the open Simulation System Model (OSSM) - is proposed and defined. This model attempts to meet the requirements of complex systems like the Numerical Propulsion Simulator System (NPSS). OSSM places no restrictions on the types of applications that can be integrated at any state of its evolution. This includes applications of different disciplines, fidelities, etc. An implementation strategy is proposed that starts with a basic prototype, and evolves over time to accommodate an increasing number of applications. Potential (standard) software is also identified which may aid in the design and implementation of the system.

Williams, Anthony D.↗
NASA NTRS2000

Developing CORBA-Based Distributed Scientific Applications From Legacy Fortran Programs

An efficient methodology is presented for integrating legacy applications written in Fortran into a distributed object framework. Issues and strategies regarding the conversion and decomposition of Fortran codes into Common Object Request Broker Architecture (CORBA) objects are discussed. Fortran codes are modified as little as possible as they are decomposed into modules and wrapped as objects. A new conversion tool takes the Fortran application as input and generates the C/C++ header file and Interface Definition Language (IDL) file. In addition, the performance of the client server computing is evaluated.

Sang, Janche↗
NASA NTRS2001

The Automatic Parallelisation of Scientific Application Codes Using a Computer Aided Parallelisation Toolkit

The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. Historically, the lack of a programming standard for using directives and the rather limited performance due to scalability have affected the take-up of this programming model approach. Significant progress has been made in hardware and software technologies, as a result the performance of parallel programs with compiler directives has also made improvements. The introduction of an industrial standard for shared-memory programming with directives, OpenMP, has also addressed the issue of portability. In this study, we have extended the computer aided parallelization toolkit (developed at the University of Greenwich), to automatically generate OpenMP based parallel programs with nominal user assistance. We outline the way in which loop types are categorized and how efficient OpenMP directives can be defined and placed using the in-depth interprocedural analysis that is carried out by the toolkit. We also discuss the application of the toolkit on the NAS Parallel Benchmarks and a number of real-world application codes. This work not only demonstrates the great potential of using the toolkit to quickly parallelize serial programs but also the good performance achievable on up to 300 processors for hybrid message passing and directive-based parallelizations.

Ierotheou, C.↗
NASA NTRS1994

Performance Evaluation of Three Distributed Computing Environments for Scientific Applications

We present performance results for three distributed computing environments using the three simulated CFD applications in the NAS Parallel Benchmark suite. These environments are the DCF cluster, the LACE cluster, and an Intel iPSC/860 machine. The DCF is a prototypic cluster of loosely coupled SGI R3000 machines connected by Ethernet. The LACE cluster is a tightly coupled cluster of 32 IBM RS6000/560 machines connected by Ethernet as well as by either FDDI or an IBM Allnode switch. Results of several parallel algorithms for the three simulated applications are presented and analyzed based on the interplay between the communication requirements of an algorithm and the characteristics of the communication network of a distributed system.

Fatoohi, Rod↗
NASA NTRS1997

High Performance Databases For Scientific Applications

The goal for this task is to develop an Extensible File System (ELFS). ELFS attacks the problem of the following: 1. Providing high bandwidth performance architectures; 2. Reducing the cognitive burden faced by applications programmers when they attempt to optimize; and 3. Seamlessly managing the proliferation of data formats and architectural differences. The approach for ELFS solution consists of language and run-time system support that permits the specification on a hierarchy of file classes.

French, James C.↗
NASA NTRS1998

Applying Fortran 90 and Object-Oriented Techniques to Scientific Applications

High-performance parallel computing is having a profound impact on the size and complexity of physical problems which can be modeled. This impact has been a long time in coming, because the learning curve in adapting to this new world of computing is steeper than was imagined.

Fortran 90 parallel computing C++↗
NASA NTRS1994

Scientific Applications of GPS on Low Earth Orbiters

The GPS flight experiment on TOPEX/Poseidon marks the first opportunity to demonstrate the high accuracy and cost effectiveness of GPS-based precise orbit determination for low Earth Orbiters. One year into the experiment, GPS has delivered orbit accuracies surpassing the best of the conventional groundbased tracking systems, DORIS and satellite laser ranging, and at a far lower cost.

altitude accuracies↗
NASA NTRS2008

Position, Navigation, and Timing: GPS Scientific Applications

This slide presentation reviews the development and deployment of the Global Positioning System (GPS). This presentation also includes measuring space and time, GPS as a tool for science, development of high precision JPL GPS receivers, and technology and applications developments.

geodesy↗