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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Design of a fault tolerant airborne digital computer. Volume 2: Computational requirements and technology

This final report summarizes the work on the design of a fault tolerant digital computer for aircraft. Volume 2 is composed of two parts. Part 1 is concerned with the computational requirements associated with an advanced commercial aircraft. Part 2 reviews the technology that will be available for the implementation of the computer in the 1975-1985 period. With regard to the computation task 26 computations have been categorized according to computational load, memory requirements, criticality, permitted down-time, and the need to save data in order to effect a roll-back. The technology part stresses the impact of large scale integration (LSI) on the realization of logic and memory. Also considered was module interconnection possibilities so as to minimize fault propagation.

Ratner, R. S.↗
NASA NTRS1997

Digital Signal Processing Based Biotelemetry Receivers

This is an attempt to develop a biotelemetry receiver using digital signal processing technology and techniques. The receiver developed in this work is based on recovering signals that have been encoded using either Pulse Position Modulation (PPM) or Pulse Code Modulation (PCM) technique. A prototype has been developed using state-of-the-art digital signal processing technology. A Printed Circuit Board (PCB) is being developed based on the technique and technology described here. This board is intended to be used in the UCSF Fetal Monitoring system developed at NASA. The board is capable of handling a variety of PPM and PCM signals encoding signals such as ECG, temperature, and pressure. A signal processing program has also been developed to analyze the received ECG signal to determine heart rate. This system provides a base for using digital signal processing in biotelemetry receivers and other similar applications.

Singh, Avtar↗
NASA NTRS2002

Adapting Digital Libraries to Continual Evolution

In this paper, we describe five investment streams (data storage infrastructure, knowledge management, data production control, data transport and security, and personnel skill mix) that need to be balanced against short-term operating demands in order to maximize the probability of long-term viability of a digital library. Because of the rapid pace of information technology change, a digital library cannot be a static institution. Rather, it has to become a flexible organization adapted to continuous evolution of its infrastructure.

Barkstrom, Bruce R.↗
NASA NTRS1993

The NT digital micro tape recorder

The description of an audio recorder may at first glance seem out of place in a conference which has been dedicated to the discussion of the technology and requirements of mass data storage. However, there are several advanced features of the NT system which will be of interest to the mass storage technologist. Moreover, there are a sufficient number of data storage formats in current use which have evolved from their audio counterparts to recommend a close attention to major innovative introductions of audio storage formats. While the existing analog micro-cassette recorder has been (and will continue to be) adequate for various uses, there are significant benefits to be gained through the application of digital technology. The elimination of background tape hiss and the availability of two relatively wide band channels (for stereo recording), for example, would greatly enhance listenability and speech intelligibility. And with the use of advanced high-density recording and LSI circuit technologies, a digital micro recorder can realize unprecedented compactness with excellent energy efficiency. This is what was accomplished with the NT-1 Digital Micro Recorder. Its remarkably compact size contributes to its portability. The high-density NT format enables up to two hours of low-noise digital stereo recording on a cassette the size of a postage stamp. Its highly energy-efficient mechanical and electrical design results in low power consumption; the unit can be operated up to 7 hours (for continuous recording) on a single AA alkaline battery. Advanced user conveniences include a multifunction LCD readout. The unit's compactness and energy-efficiency, in particular, are attributes that cannot be matched by existing analog and digital audio formats. The size, performance, and features of the NT format are of benefit primarily to those who desire improved portability and audio quality in a personal memo product. The NT Recorder is the result of over ten years of intensive, multi-disciplinary research and development. What follows is a discussion of the technologies that have made the NT possible: (1) NT format mechanics, (2) NT media, (3) NT circuitry and board.

Sasaki, Toshikazu↗
NASA NTRSDate not supplied

NASA Earth System Digital Twins (ESDT) For a Sustainable Future

An Earth System Digital Twin (or ESDT) is an Information System for Understanding, Forecasting, and Conjecturing the complex interconnections among Earth systems, including anthropomorphic forcings and impacts to humanity. More specifically, an Earth System Digital Twin is a dynamic and interactive information system that first provides a digital replica of the past and current states of the Earth or Earth system, as accurately and timely as possible (i.e., the “What Now”); second allows for computing forecasts of future states under nominal assumptions and based on the current replica (i.e., the “What Next”); and third offers the capability to investigate many hypothetical scenarios under varying impact assumptions (i.e., the “What If”). The full power of digital twins is that, through an integrated representation and standardized tools and software technologies, the same digital replica can address the needs of multiple users at various resolutions (spatial and temporal) and for various applications (science, economic, policy, etc.) – “from farmer to scientist”. Since 2020, NASA’s Earth Science Technology’s Intelligent Systems Programs have started defining and investigating ESDTs. After several workshops, more than 15 projects have been funded to develop technologies and components as well as a few prototype ESDT systems. An ESDT architecture framework has been defined, and it is now being used to develop a Coastal Zone Digital Twin (CZ-DT), in coordination with NOAA and CNES. Additional projects have also just been selected to build additional ESDT technologies and prototypes. The details of these Programs will be detailed at the conference.

Earth Science Remote Sensing; Information Systems↗
NASA NTRS2000

Using DSP technology to simplify deep space ranging

Commercially available Digital Signal Processing (DSP) technology has enabled a new spacecraft ranging design. The new design reduces overall size, parts count, and complexity. The design implementation will also meet the Jet Propulsion Laboratory (JPL) requirements for both near-Earth and deep space ranging.

ranging DSP DSN NSP↗
NASA NTRS1980

A digitally implemented communications experiment utilizing the communications technology satellite, Hermes

Developments which will reduce the costs associated with the distribution of satellite services are considered with emphasis on digital communication link implementation. A digitally implemented communications experiment (DICE) which demonstrates the flexibility and efficiency of digital transmission of television video and audio, telephone voice, and high-bit-rate data is described. The utilization of the DICE system in a full duplex teleconferencing mode is addressed. Demonstration teleconferencing results obtained during the conduct of two sessions of the 7th AIAA Communication Satellite Systems Conference are discussed. Finally, the results of link characterization tests conducted to determine (1) relationships between the Hermes channel 1 EIRP and DICE model performance and (2) channel spacing criteria for acceptable multichannel operation, are presented.

Jackson, H. D.↗
NASA NTRS1996

DCTune Perceptual Optimization of Compressed Dental X-Rays

In current dental practice, x-rays of completed dental work are often sent to the insurer for verification. It is faster and cheaper to transmit instead digital scans of the x-rays. Further economies result if the images are sent in compressed form. DCTune is a technology for optimizing DCT (digital communication technology) quantization matrices to yield maximum perceptual quality for a given bit-rate, or minimum bit-rate for a given perceptual quality. Perceptual optimization of DCT color quantization matrices. In addition, the technology provides a means of setting the perceptual quality of compressed imagery in a systematic way. The purpose of this research was, with respect to dental x-rays, 1) to verify the advantage of DCTune over standard JPEG (Joint Photographic Experts Group), 2) to verify the quality control feature of DCTune, and 3) to discover regularities in the optimized matrices of a set of images. We optimized matrices for a total of 20 images at two resolutions (150 and 300 dpi) and four bit-rates (0.25, 0.5, 0.75, 1.0 bits/pixel), and examined structural regularities in the resulting matrices. We also conducted psychophysical studies (1) to discover the DCTune quality level at which the images became 'visually lossless,' and (2) to rate the relative quality of DCTune and standard JPEG images at various bitrates. Results include: (1) At both resolutions, DCTune quality is a linear function of bit-rate. (2) DCTune quantization matrices for all images at all bitrates and resolutions are modeled well by an inverse Gaussian, with parameters of amplitude and width. (3) As bit-rate is varied, optimal values of both amplitude and width covary in an approximately linear fashion. (4) Both amplitude and width vary in systematic and orderly fashion with either bit-rate or DCTune quality; simple mathematical functions serve to describe these relationships. (5) In going from 150 to 300 dpi, amplitude parameters are substantially lower and widths larger at corresponding bit-rates or qualities. (6) Visually lossless compression occurs at a DCTune quality value of about 1. (7) At 0.25 bits/pixel, comparative ratings give DCTune a substantial advantage over standard JPEG. As visually lossless bit-rates are approached, this advantage of necessity diminishes. We have concluded that DCTune optimized quantization matrices provide better visual quality than standard JPEG. Meaningful quality levels may be specified by means of the DCTune metric. Optimized matrices are very similar across the class of dental x-rays, suggesting the possibility of a 'class-optimal' matrix. DCTune technology appears to provide some value in the context of compressed dental x-rays.

Watson, Andrew B.↗
NASA NTRS1994

Lightning Protection

Kit-built airplanes are more affordable because they are assembled by the owner and do not require Federal Aviation Administration (FAA) certification. The Glasair III, is an advanced technology homebuilt, constructed of a fiberglass and graphite fiber composite material, and equipped with digital instruments. Both technologies make the airplane more susceptible to lightning effects. When Glasair manufacturer, Stoddard-Hamilton, decided that lightning protection would enable more extensive instrument flight and make the plane more marketable, they proposed a joint development program to NASA Langley Research Center (LAR). Under a Small Business Innovation Research (SBIR) contract, Langley contractors designed and tested a lightning protection system, and the Glasair III-LP became the first kit-built composite aircraft to be lightning tested and protection-verified under FAA guidelines for general aviation aircraft.

Source record↗
NASA NTRSDate not supplied

NASA's Advanced Information Systems Technology (AIST): Combining New Observing Strategies and Analytics Frameworks to Build Earth System Digital Twins

NASA's Advanced Information Systems Technology (AIST) Program is one of several Technology programs managed by the Earth Science Technology Office (ESTO) in the Earth Science Division (ESD). The AIST Program focuses on advanced information systems and novel computer science technologies that will be needed by NASA Earth Science in the next 5 to 10 years. The three main thrusts of the AIST Program deal with New Observing Strategies, Analytic Collaborative Frameworks and Earth System Digital Twins. This paper describes these three thrusts and how they work together to create future Earth Science information systems.

Jacqueline Le Moigne↗
NASA NTRS1979

Spectral feature classification and spatial pattern recognition

This paper introduces a spatial pattern recognition processing concept involving the use of spectral feature classification technology and coherent optical correlation. The concept defines a hybrid image processing system incorporating both digital and optical technology. The hybrid instrument provides simplified pseudopattern images as functions of pixel classification from information embedded within a real-scene image. These pseudoimages become simplified inputs to an optical correlator for use in a subsequent pattern identification decision useful in executing landmark pointing, tracking, or navigating functions. Real-time classification is proposed as a research tool for exploring ways to enhance input signal-to-noise ratio as an aid in improving optical correlation. The approach can be explored with developing technology, including a current NASA Langley Research Center technology plan that involves a series of related Shuttle-borne experiments. A first-planned experiment, Feature Identification and Location Experiment (FILE), is undergoing final ground testing, and is scheduled for flight on the NASA Shuttle (STS2/flight OSTA-1) in 1980. FILE will evaluate a technique for autonomously classifying earth features into the four categories: bare land; water; vegetation; and clouds, snow, or ice.

Sivertson, W. E., Jr.↗
NASA NTRS1990

On-board switching and processing

Findings from NASA's space electronics division's (SED's) advanced systems studies related to future communications satellite services that will require onboard switching and processing technology are reviewed. SED's digital signal switching and processing technology program is reviewed. This program responds to specific systems technology development needs for enabling commercial development of future satellite services. The technologies include: modulators, demodulators, and forward error-correction hardware for space- and ground-based applications; onboard information switching and processing, onboard network control, and health monitoring; and cost-efficient ground terminals. The in-house systems integration, test, and evaluation (SITE) project, which includes a laboratory testbed for evaluating technology in a simulated systems environment, is reviewed.

Harrold, Joseph L.↗
NASA NTRS2004

Reconfigurable Transceiver and Software-Defined Radio Architecture and Technology Evaluated for NASA Space Communications

The NASA Glenn Research Center is investigating the development and suitability of a software-based open-architecture for space-based reconfigurable transceivers (RTs) and software-defined radios (SDRs). The main objectives of this project are to enable advanced operations and reduce mission costs. SDRs are becoming more common because of the capabilities of reconfigurable digital signal processing technologies such as field programmable gate arrays and digital signal processors, which place radio functions in firmware and software that were traditionally performed with analog hardware components. Features of interest of this communications architecture include nonproprietary open standards and application programming interfaces to enable software reuse and portability, independent hardware and software development, and hardware and software functional separation. The goals for RT and SDR technologies for NASA space missions include prelaunch and on-orbit frequency and waveform reconfigurability and programmability, high data rate capability, and overall communications and processing flexibility. These operational advances over current state-of-art transceivers will be provided to reduce the power, mass, and cost of RTs and SDRs for space communications. The open architecture for NASA communications will support existing (legacy) communications needs and capabilities while providing a path to more capable, advanced waveform development and mission concepts (e.g., ad hoc constellations with self-healing networks and high-rate science data return). A study was completed to assess the state of the art in RT architectures, implementations, and technologies. In-house researchers conducted literature searches and analysis, interviewed Government and industry contacts, and solicited information and white papers from industry on space-qualifiable RTs and SDRs and their associated technologies for space-based NASA applications. The white papers were evaluated, compiled, and used to assess RT and SDR system architectures and core technology elements to determine an appropriate investment strategy to advance these technologies to meet future mission needs. The use of these radios in the space environment represents a challenge because of the space radiation suitability of the components, which drastically reduces the processing capability. The radios available for space are considered to be RTs (as opposed to SDRs), which are digitally programmable radios with selectable changes from an architecture combining analog and digital components. The limited flexibility of this design contrasts against the desire to have a power-efficient solution and open architecture.

Reinhart, Richard C.↗
NASA NTRS1993

The Visible Human Project of the National Library of Medicine: Remote access and distribution of a multi-gigabyte data set

As part of the 1986 Long-Range Plan for the National Library of Medicine (NLM), the Planning Panel on Medical Education wrote that NLM should '...thoroughly and systematically investigate the technical requirements for and feasibility of instituting a biomedical images library.' The panel noted the increasing use of images in clinical practice and biomedical research. An image library would complement NLM's existing bibliographic and factual database services and would ideally be available through the same computer networks as are these current NLM services. Early in 1989, NLM's Board of Regents convened an ad hoc planning panel to explore possible roles for the NLM in the area of electronic image libraries. In its report to the Board of Regents, the NLM Planning Panel on Electronic Image Libraries recommended that 'NLM should undertake a first project building a digital image library of volumetric data representing a complete, normal adult male and female. This Visible Human Project will include digitized photographic images for cryosectioning, digital images derived from computerized tomography, and digital magnetic resonance images of cadavers.' The technologies needed to support digital high resolution image libraries, including rapid development; and that NLM encourage investigator-initiated research into methods for representing and linking spatial and textual information, structural informatics. The first part of the Visible Human Project is the acquisition of cross-sectional CT and MRI digital images and cross-sectional cryosectional photographic images of a representative male and female cadaver at an average of one millimeter intervals. The corresponding cross-sections in each of the three modalities are to be registerable with one another.

Ackerman, Michael J.↗
NASA NTRS1977

System design for the digitally implemented communications experiment /DICE/

Full-duplex digital television providing a teleconference capability is to be evaluated in an experimental program utilizing the Communications Technology Satellite. The digitally implemented communications experiment employs a QPSK modulator-demodulator capable of operation over a wide range of bit rates. In addition to simultaneous data transmission (used for digital high-speed facsimiles and remote computer terminals), voice transmission through four-to-one compression will be studied.

Gatfield, A. G.↗
NASA NTRS1984

The 3SPACE digitizer: A new input device for solid geometry modeling

The 3SPACE Digitizer is a derivation of SPASYN, which is a patented magnetic transducing system offering an accurate method of calculating the location of one object relative to another. SPASYN uses low-frequency magnetic fields to measure both the position and orientation of its sensor relative to its transmitter. The 3SPACE Digitizer unit consists of a system's electronics unit, a model table, a stylus, and a keypad. In operation, the 3SPACE Digitizer determines the X, Y, Z coordinates of any point located on a low-conductive, three-dimensional model. This data, along with the orientation of the Digitizer's stylus, is immediately available for transmission to a host computer or graphics terminal. Digitization is effected by touching the point to be measured with the tip of a handheld stylus. The 3SPACE Digitizer presents new opportunities for interacting with computers in a large number of engineering and scientific applications. Developed from proven military technology, the 3SPACE Digitizer significantly simplifies three-dimensional digitization and overcomes many of the problems that once plagued such procedures. Its ability to digitize solid objects makes it a valuable new tool for computer-aided design and manufacturing.

Scully, J.↗
NASA NTRS1984

Role of research aircraft in technology development

NASA supercritical wing technology, and the digital fly-by-wire program are discussed as used on the F-8 research aircraft. Furthermore, the Highly Maneuverable Aircraft Technology (HiMAT) program, using a 0.44-scale, 3500 lb jet-powered remotely piloted research aircraft, is analyzed. Highly accurate data on aerodynamic and structural loads and deflection data were obtained from model flight tests. In addition, an oblique-wing technology is discussed through the example of the piloted AD-1 research aircraft, noting the low cost of the experiment. Other topics include: integrated system technology; generic forces of the research aircraft program; and aeronautical technology application trends.

Szalai, K. J.↗