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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Parallel Gaussian elimination of a block tridiagonal matrix using multiple microcomputers

The solution of a block tridiagonal matrix using parallel processing is demonstrated. The multiprocessor system on which results were obtained and the software environment used to program that system are described. Theoretical partitioning and resource allocation for the Gaussian elimination method used to solve the matrix are discussed. The results obtained from running 1, 2 and 3 processor versions of the block tridiagonal solver are presented. The PASCAL source code for these solvers is given in the appendix, and may be transportable to other shared memory parallel processors provided that the synchronization outlines are reproduced on the target system.

Blech, Richard A.↗
NASA NTRS1989

A real time microcomputer implementation of sensor failure detection for turbofan engines

An algorithm was developed which detects, isolates, and accommodates sensor failures using analytical redundancy. The performance of this algorithm was demonstrated on a full-scale F100 turbofan engine. The algorithm was implemented in real-time on a microprocessor-based controls computer which includes parallel processing and high order language programming. Parallel processing was used to achieve the required computational power for the real-time implementation. High order language programming was used in order to reduce the programming and maintenance costs of the algorithm implementation software. The sensor failure algorithm was combined with an existing multivariable control algorithm to give a complete control implementation with sensor analytical redundancy. The real-time microprocessor implementation of the algorithm which resulted in the successful completion of the algorithm engine demonstration, is described.

Delaat, John C.↗
NASA NTRS1987

Low cost, microcomputer-based interactive analysis system for direct-reception and archived remote sensing data

A hardware/software system has been developed for use in meteorological field experiments and by developing countries which need low-cost remote sensing data analysis capabilities. The system can directly receive satellite transmissions of the AVHRR, TOVS, Argos, GOES, GMS, and Meteosat systems. Also, the system can process computer tapes from Landsat. Received data are ingested directly into the computer's disk storage, eliminating the need for a wide-band analog tape drive. Data may be interpreted in terms of cloud imagery, cloudtop temperature, sea surface temperature, vegetation index, and temperature/humidity profiles with overlays of geographic boundaries and latitude/longitude grids. The image processing, enhancement functions, and modeling capabilities of the system are discussed.

Vermillion, Charles H.↗
NASA NTRS1990

Advanced detection, isolation, and accommodation of sensor failures in turbofan engines: Real-time microcomputer implementation

The objective of the Advanced Detection, Isolation, and Accommodation Program is to improve the overall demonstrated reliability of digital electronic control systems for turbine engines. For this purpose, an algorithm was developed which detects, isolates, and accommodates sensor failures by using analytical redundancy. The performance of this algorithm was evaluated on a real time engine simulation and was demonstrated on a full scale F100 turbofan engine. The real time implementation of the algorithm is described. The implementation used state-of-the-art microprocessor hardware and software, including parallel processing and high order language programming.

Delaat, John C.↗
NASA NTRS1990

Development of microcomputer-based mental acuity tests for repeated-measures studies

The purpose of this report is to detail the development of the Automated Performance Test System (APTS), a computer battery of mental acuity tests that can be used to assess human performance in the presence of toxic elements and environmental stressors. There were four objectives in the development of APTS. First, the technical requirements for developing APTS followed the tenets of the classical theory of mental tests which requires that tests meet set criteria like stability and reliability (the lack of which constitutes insensitivity). To be employed in the study of the exotic conditions of protracted space flight, a battery with multiple parallel forms is required. The second criteria was for the battery to have factorial multidimensionality and the third was for the battery to be sensitive to factors known to compromise performance. A fourth objective was for the tests to converge on the abilities entailed in mission specialist tasks. A series of studies is reported in which candidate APTS tests were subjected to an examination of their psychometric properties for repeated-measures testing. From this work, tests were selected that possessed the requisite metric properties of stability, reliability, and factor richness. In addition, studies are reported which demonstrate the predictive validity of the tests to holistic measures of intelligence.

Kennedy, R. S.↗
NASA NTRS1990

A real time microcomputer implementation of sensor failure detection for turbofan engines

An algorithm was developed that detects, isolates, and accommodates sensor failures using analytical redundancy. The performance of this algorithm has been demonstrated on a full-scale F100 turbofan engine. The algorithm was implemented in real-time on a microprocessor-based controls computer which includes parallel processing and high order language programming. Parallel processing was used to achieve the required computational power for the real-time implementation. High order language programming was used in order to reduce the programming and maintenance costs of the algorithm implementation software. The sensor failure algorithm was combined with an existing multivariable control algorithm to give a complete control implementation with sensor analytical redundancy. The real-time microprocessor implementation of the algorithm, which resulted in the successful completion of the algorithm engine demonstration, is described.

Delaat, John C.↗
NASA NTRS1991

An efficient microcomputer system for the analysis of particle image velocimetry specklegrams

An efficient image processing system is described for the automatic analysis of particle image velocimetry (PIV) fringe patterns. Each interrogation point takes 1 second to analyze; a complete specklegram can be interrogated at 1000 points in approximately 15 minutes. Incorporated in the analysis is a means for automatic replacement of spurious velocity vectors without either re-interrogation of the specklegram or interpolation between neighboring data points. The sucess of the above system is demonstrated by application of the PIV technique to the study of the sink-driven cavity flow. This flow is studied as part of a larger program to investigate trapped vortex flows as a means of lift enhancement on swept wings.

Wadcock, Alan J.↗
NASA NTRS1991

A microcomputer program for estimating low altitude wind and turbulence fields

Past efforts to develop methods for objective wind analysis and to provide turbulence estimates to pilots are reviewed. The present approach involves a wind module and a turbulence module. The wind module extends the critical dividing streamline concept and past developments in mass-conserving wind interpolation schemes. The turbulence module is based on recent efforts to develop practical atmospheric turbulence parameterization schemes based on lapse rate, wind shear, surface heating, and surface roughness. The lapse rate and wind shear are readily obtained from the wind module. Surface roughness and heating come from land use information and net radiation estimates derived from cloud cover, terrain slope, local time, and latitude. This system is argued to have considerable potential for providing useful online information for many kinds of aircraft operations.

Ludwig, F. L.↗
NASA NTRS1994

EGADS: A microcomputer program for estimating the aerodynamic performance of general aviation aircraft

EGADS is a comprehensive preliminary design tool for estimating the performance of light, single-engine general aviation aircraft. The software runs on the Apple Macintosh series of personal computers and assists amateur designers and aeronautical engineering students in performing the many repetitive calculations required in the aircraft design process. The program makes full use of the mouse and standard Macintosh interface techniques to simplify the input of various design parameters. Extensive graphics, plotting, and text output capabilities are also included.

Melton, John E.↗
NASA NTRS1981

Automated Power Systems Management (APSM)

A breadboard power system incorporating autonomous functions of monitoring, fault detection and recovery, command and control was developed, tested and evaluated to demonstrate technology feasibility. Autonomous functions including switching of redundant power processing elements, individual load fault removal, and battery charge/discharge control were implemented by means of a distributed microcomputer system within the power subsystem. Three local microcomputers provide the monitoring, control and command function interfaces between the central power subsystem microcomputer and the power sources, power processing and power distribution elements. The central microcomputer is the interface between the local microcomputers and the spacecraft central computer or ground test equipment.

Bridgeforth, A. O.↗
NASA NTRS1981

Bi-directional communication interface for microprocessor-to-system/370

The design and operation of a bi-directional communication interface between a microcomputer and the IBM System/370 is documented. The hardware unit interconnects a modem to interface to the S/370, the microcomputer with an EIA I/O port, and a terminal for sending and receiving data from either the microcomputer or the S/370. Also described is the software necessary for the two-way interface. This interface is designed so that no modifications need to be made to the terminal, modem, or microcomputer.

Fischer, J. P.↗
NASA NTRS1982

Bi-directional communication interface for microprocessor-to-system/370

The design and operation of a bi-directional communication interface between a microcomputer and the IBM System/370 is documented. The hardware unit inter-connects a modem to interface to the S/370, the microcomputer with an EIA I/O port, and a terminal for sending and receiving data from either the microcomputer of the S/370. The software necessary for the two-way interface is also described. This interface was designed so that no modifications need to be made to the terminal, modem or microcomputer.

Fischer, J. P.↗
NASA NTRS1989

Development of a software interface for optical disk archival storage for a new life sciences flight experiments computer

The current Life Sciences Laboratory Equipment (LSLE) microcomputer for life sciences experiment data acquisition is now obsolete. Among the weaknesses of the current microcomputer are small memory size, relatively slow analog data sampling rates, and the lack of a bulk data storage device. While life science investigators normally prefer data to be transmitted to Earth as it is taken, this is not always possible. No down-link exists for experiments performed in the Shuttle middeck region. One important aspect of a replacement microcomputer is provision for in-flight storage of experimental data. The Write Once, Read Many (WORM) optical disk was studied because of its high storage density, data integrity, and the availability of a space-qualified unit. In keeping with the goals for a replacement microcomputer based upon commercially available components and standard interfaces, the system studied includes a Small Computer System Interface (SCSI) for interfacing the WORM drive. The system itself is designed around the STD bus, using readily available boards. Configurations examined were: (1) master processor board and slave processor board with the SCSI interface; (2) master processor with SCSI interface; (3) master processor with SCSI and Direct Memory Access (DMA); (4) master processor controlling a separate STD bus SCSI board; and (5) master processor controlling a separate STD bus SCSI board with DMA.

Bartram, Peter N.↗
NASA NTRS1977

Development of a character, line and point display system

A compact graphics terminal for use as the input to a computerized medical records system is described. The principal mode of communication between the terminal and the records system is by checklists and menu selection. However, the terminal accepts short, handwritten messages as well as conventional alphanumeric input. The terminal consists of an electronic tablet, a display, a microcomputer controller, a character generator, and a refresh memory for the display. An Intel SBC 80/10 microcomputer controls the flow of information and a 16 kilobyte memory stores the point-by-point array of information to be displayed. A specially designed interface continuously generates the raster display without the intervention of the microcomputer.

Owen, E. W.↗
NASA NTRS1977

A data acquisition and handling system for the measurement of radial plasma transport rates

A microcomputer serves as a programmable interface between high frequency transient recorders and a digital incremental tape recorder. An interactive program stored in the microcomputer permits the operator to enter various experimental parameters in response to queries from the system. The microcomputer then stores both the experimental parameters and the raw digital data on tape for later processing by a general purpose computer.

Krawczonek, W. M.↗
NASA NTRS1979

Results of the second flight test of the Loran-C receiver/data collection system

The components of the Loran-C navigation system which were developed thus far are a phase-locked-loop receiver and a microcomputer development system. The microcomputer is being used as a means of testing and implementing software to handle sensor control and navigation calculations. Currently, the microcomputer is being used to collect and record data from the receiver in addition to development work. With these components, it was possible to record receiver data over a period of time and then reduce this data to obtain statistical information. It was particularly interesting to load the equipment developed in the laboratory into an aircraft and collect data while in flight. For initial flight tests, some important considerations were how well the entire system will perform in the field, signal strength levels while on the ground and in the air, the amount of noise present, changing of signal-to-noise ratio for various aircraft configurations and maneuvers, receiver overloading due to other equipment and antennas, and the overall usefulness of Loran-C as a navigation aid.

Fischer, J. P.↗