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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 271 records · Page 15

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NASA NTRS1988

Application of the hypercube parallel processor to a large-scale moment method code

The applicability of a parallel computing architecture to the solution of a large-scale moment-method code is investigated. Specifically, the NEC (Numerical Electromagnetics Code) method-of-moments scattering program is implemented on a hypercube parallel processor. The accuracy and the increase in the speed of execution on this parallel architecture are demonstrated. The results show a very large reduction in execution time for large problems. The great potential of this parallel processor is shown for interactive solution of large NEC problems as well as other moment-method techniques such as the finite-element method.

Manshadi, Farzin↗

NASA NTRS1988

VLSI high speed packet processor

The Goddard Space Flight Center Mission Operations and Data Systems Directorate has developed a packet processor card utilizing semicustom very large scale integration (VLSI) devices, microprocessors, and programmable gate arrays to support the implementation of multichannel telemetry data capture systems. This card will receive synchronized error corrected telemetry transfer frames and output annotated application packets derived from this data. An adaptable format capability is provided by the programmability of three microprocessors while the throughput capability of the packet processor is achieved by a data pipeline consisting of two separate RAM systems controlled by specially designed semicustom VLSI logic.

Grebowsky, Gerald J.↗

NASA NTRS1988

LARP - An adaptive LDV signal processor

Recent attempts at realization of a frequency domain signal processor exhibit practical drawbacks such as manual gain, filter and sampling adjustments, and simplistic adaptations of frequency domain techniques. This paper introduces an adaptive LDV signal processor, one which requires no operator intervention under any circumstances by adapting dynamically to burst characteristics, while surpassing all previous techniques in range and accuracy.

Baker, Glenn D.↗

NASA NTRS1990

Frequency-Domain Signal Processor For Laser Velocimeter

Dynamic range and accuracy increased. New signal processor for laser-velocimeter (LV) applications overcomes major limitations of present signal processors. System requires no input-signal conditioning other than that provided by amplifiers; it operates in instantaneous mode at signal levels from bursts containing as few as 150 photons down to photon-resolved regime in averaging mode. Digital value of signal-burst frequency sent to external computer system for conversion to value of absolute frequency. Residual turbulence intensity 0.2 percent, with little dependence on signal-to-noise ratio.

Meyers, James F.↗

NASA NTRS1988

Scan line graphics generation on the massively parallel processor

Described here is how researchers implemented a scan line graphics generation algorithm on the Massively Parallel Processor (MPP). Pixels are computed in parallel and their results are applied to the Z buffer in large groups. To perform pixel value calculations, facilitate load balancing across the processors and apply the results to the Z buffer efficiently in parallel requires special virtual routing (sort computation) techniques developed by the author especially for use on single-instruction multiple-data (SIMD) architectures.

Dorband, John E.↗

NASA NTRS1990

Onboard processor technology review

The general need and requirements for the onboard embedded processors necessary to control and manipulate data in spacecraft systems are discussed. The current known requirements are reviewed from a user perspective, based on current practices in the spacecraft development process. The current capabilities of available processor technologies are then discussed, and these are projected to the generation of spacecraft computers currently under identified, funded development. An appraisal is provided for the current national developmental effort.

Benz, Harry F.↗

NASA NTRS1990

Effects of error sources on the parallelism of an optical matrix-vector processor

The error sources in a high accuracy optical matrix-vector processor are analyzed by numerical simulation in terms of their effects on the parallelism and speed of the processor. These effects are detailed for radices -2, -4 and -8. Radix -4 is shown to provide maximum parallel processing capabilities under the effects of the system's error sources. Processing speed is shown to be a function of matrix partitioning and the number of parallel processing channels. Consequently, radix -4 operation provides a higher processing speed than radix -2 and -8 for most matrix-vector multiplications when error source effects are considered.

Perlee, Caroline J.↗

NASA NTRS1990

Simultaneous multivelocity component laser Doppler velocimetry using one digital frequency processor

Digital frequency processing used in conjunction with optical frequency shifting is an ideal way to achieve simultaneous multivelocity component measurements in laser Doppler velocimetry. This becomes obvious once realized that multivelocity component information at different frequency offsets can be obtained directly from the composite frequency spectrum of a single-channel digital frequency processor. The approach has numerous advantages over the very popular approach of using a different laser wavelength, photodetector, and signal processor for each velocity component.

Johnson, D. A.↗

NASA NTRS1991

Programmable Maintenance Processor For XAIDS

Programmable maintenance processor (MAINT) made of commercially available integrated circuits. Autonomous one of four digital electronic processors in extended aircraft interrogation and display system (XAIDS). Developed for testing of system and application computer programs as well as for testing equipment. MAINT has independent terminal and printer interfaces and dedicated magnetic bubble memory storing system-testing sequences entered from terminal. Software for MAINT written in PLM86 programming language and broken into four separate modules.

Glover, Richard↗

NASA NTRS1990

A Byzantine resilient processor with an encoded fault-tolerant shared memory

The memory requirements for ultra-reliable computers are expected to increase due to future increases in mission functionality and operating-system requirements. This increase will have a negative effect on the reliability and cost of the system. Increased memory size will also reduce the ability to reintegrate a channel after a transient fault, since the time required to reintegrate a channel in a conventional fault-tolerant processor is dominated by memory realignment time. A Byzantine Resilient Fault-Tolerant Processor with Fault-Tolerant Shared Memory (FTP/FTSM) is presented as a solution to these problems. The FTSM uses an encoded memory system, which reduces the memory requirement by one-half compared to a conventional quad-FTP design. This increases the reliability and decreases the cost of the system. The realignment problem is also addressed by the FTSM. Because any single error is corrected upon a read from the FTSM, a faulty channel's corrupted memory does not need realignment before reintegration of the faulty channel. A combination of correct-on-access and background scrubbing is proposed to prevent the accumulation of transient errors in the memory. With a hardware-implemented scrubber, the scrubbing cycle time, and therefore the memory fault latency, can be upper-bounded at a small value. This technique increases the reliability of the memory system and facilitates validation of its reliability model.

Butler, Bryan↗

NASA NTRS1990

Reduction of solar vector magnetograph data using a microMSP array processor

The processing of raw data obtained by the solar vector magnetograph at NASA-Marshall requires extensive arithmetic operations on large arrays of real numbers. The objectives of this summer faculty fellowship study are to: (1) learn the programming language of the MicroMSP Array Processor and adapt some existing data reduction routines to exploit its capabilities; and (2) identify other applications and/or existing programs which lend themselves to array processor utilization which can be developed by undergraduate student programmers under the provisions of project JOVE.

Kineke, Jack↗

NASA NTRS1990

The 3D laser radar vision processor system

Loral Defense Systems (LDS) developed a 3D Laser Radar Vision Processor system capable of detecting, classifying, and identifying small mobile targets as well as larger fixed targets using three dimensional laser radar imagery for use with a robotic type system. This processor system is designed to interface with the NASA Johnson Space Center in-house Extra Vehicular Activity (EVA) Retriever robot program and provide to it needed information so it can fetch and grasp targets in a space-type scenario.

Sebok, T. M.↗

NASA NTRS1989

The Alaska SAR processor - Operations and control

The Alaska SAR (synthetic-aperture radar) Facility (ASF) will be capable of receiving, processing, archiving, and producing a variety of SAR image products from three satellite-borne SARs: E-ERS-1 (ESA), J-ERS-1 (NASDA) and Radarsat (Canada). Crucial to the success of the ASF is the Alaska SAR processor (ASP), which will be capable of processing over 200 100-km x 100-km (Seasat-like) frames per day from the raw SAR data, at a ground resolution of about 30 m x 30 m. The processed imagery is of high geometric and radiometric accuracy, and is geolocated to within 500 m. Special-purpose hardware has been designed to execute a SAR processing algorithm to achieve this performance. This hardware is currently undergoing acceptance testing for delivery to the University of Alaska. Particular attention has been devoted to making the operations semi-automated and to providing a friendly operator interface via a computer workstation. The operations and control of the Alaska SAR processor are described.

Carande, Richard E.↗

NASA NTRS1990

An innovative on-board processor for lightsats

The Applied Physics Laboratory (APL) has developed a flightworthy custom microprocessor that increases capability and reduces development costs of lightsat science instruments. This device, called the FRISC (FORTH Reduced Instruction Set Computer), directly executes the high-level language called FORTH, which is ideally suited to the multitasking control and data processing environment of a spaceborne instrument processor. The FRISC will be flown as the onboard processor in the Magnetic Field Experiment on the Freja satllite. APL has achieved a significant increase in onboard processing capability with no increase in cost when compared to the magnetometer instrument on Freja's predecessor, the Viking satellite.

Henshaw, R. M.↗

NASA NTRS1990

Rapid recovery from transient faults in the fault-tolerant processor with fault-tolerant shared memory

The Draper fault-tolerant processor with fault-tolerant shared memory (FTP/FTSM), which is designed to allow application tasks to continue execution during the memory alignment process, is described. Processor performance is not affected by memory alignment. In addition, the FTP/FTSM incorporates a hardware scrubber device to perform the memory alignment quickly during unused memory access cycles. The FTP/FTSM architecture is described, followed by an estimate of the time required for channel reintegration.

Harper, Richard E.↗

NASA NTRS1992

Initializing Embedded Data Processors From A Single Source

Initial-computer-program-loading system provides startup information to all embedded data processors (EDP's) in general-purpose computer system. Remote processors given image of startup diskette so real local diskette and drive unneeded. System less complex and equipment costs less. Additional benefit, initial program loading tests bus. If boot-up program transmitted correctly, bus assumed to be operating properly.

Chavez, Edward A.↗

NASA NTRS1992

Optical-Input, Optical-Output Morphological Processor

Some advantages of optical and electronic processing combined. Proposed optical-input/optical-output morphological processor is optoelectronic assembly performing some binary operations on picture elements of binary input image, yielding processed binary output image. Number of such processors cascaded to form more complicated image-processing system. Use of optics as connection medium makes rate of processing faster than in all-electronic system designed to perform same overall processing functions. At the same time, use of electronics as processing medium provides flexibility of reconfiguration not available in all-optical system.

Yu, Jeffrey W.↗

NASA NTRS1991

Large angle transient dynamics (LATDYN) documentation. Post-processor manual

The post processor program was developed to view Large Angle Transient Dynamics (LATDYN) output data in predefined, predetermined formats. The post processor is used for plotting data, creating and maintaining a data base of plotting requests, comparing and manipulating data sets in the data base, and the preparing plots for documentation.

Mitchum, Maria V.↗