Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “logic”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Optimization of the space shuttle entry guidance lateral deadband, minimum bank angle logic

The lateral deadband and minimum bank angle schedule were studied. Results used by the analytic drag control entry guidance system are presented. Lateral deadband limits and configuration were investigated and possible changes in the minimum bank angle schedule to improve crossrange control and drag acceleration control for entry were examined. The study recommends a 12.5 deg lateral deadband to accommodate low dispersions of up to 23%.

Bump, P. B.↗
NASA NTRS1977

Standard high-reliability integrated circuit logic packaging

A family of standard, high-reliability hardware used for packaging digital integrated circuits is described. The design transition from early prototypes to production hardware is covered and future plans are discussed. Interconnections techniques are described as well as connectors and related hardware available at both the microcircuit packaging and main-frame level. General applications information is also provided.

Slaughter, D. W.↗
NASA NTRS1979

Algorithms and logic for incorporating MLS back azimuth information into the NASA TCV B-737 airplane area navigation system

Navigation position estimates are based on range information form a randomly located DME and MLS back azimuth angular information. The MLS volmetric coverage checks are performed to ensure that proper navigation inputs are being utilized. These algorithms and volumetric checks were designed so that they could be added to most existing area navigation systems with minimum software modification.

Knox, C. E.↗
NASA NTRS1980

A general logic structure for custom LSI'S

Structure composed of standardized-circuit arrays reduces cost and complexity of fabricating special integrated circuits. Desired circuits are formed from basic mask, custom cuts, and contact points. Interactive computer program speeds design.

Sievers, M. W.↗
NASA NTRS1981

Quantitative simulation of a magnetospheric substorm. I - Model logic and overview

Results of a comprehensive computer simulation of the behavior of the earth's inner magnetosphere during a substorm-type event are reported. It is pointed out that the computer model self-consistently computes electric fields, currents, and plasma distributions and velocities in the inner-magnetosphere/ionosphere system; parallel electric fields and ionospheric neutral winds, however, are not included. The basic equations of the model are derived, and the inputs are described. An overview of the results is also given. The first appendix contains derivations of general, useful laws of bounce-averaged gradient, curvature, and E x B drifts in a plasma with isotropic pitch angle distribution. The second appendix gives a description of the numerical method used in the simulation.

Harel, M.↗
NASA NTRS1982

Inexpensive Logic-Level Converter

Relatively-simple transformer circuit boosts 0-to-5 volt pulses from TTL circuitry to plus or minus 10-volt pulses for transmission over data bus. Also reduces bus voltages to lower voltages required by TTL circuitry. Circuit consists of transformer, two voltage-reference networks, quad differential line receiver, and line driver.

Wilcox, S. W.↗
NASA NTRS1984

Logical optimization for database uniformization

Data base uniformization refers to the building of a common user interface facility to support uniform access to any or all of a collection of distributed heterogeneous data bases. Such a system should enable a user, situated anywhere along a set of distributed data bases, to access all of the information in the data bases without having to learn the various data manipulation languages. Furthermore, such a system should leave intact the component data bases, and in particular, their already existing software. A survey of various aspects of the data bases uniformization problem and a proposed solution are presented.

Grant, J.↗
NASA NTRS1984

Optical flip-flops and sequential logic circuits using a liquid crystal light valve

This paper is concerned with the application of optics to digital computing. A Hughes liquid crystal light valve is used as an active optical element where a weak light beam can control a strong light beam with either a positive or negative gain characteristic. With this device as the central element the ability to produce bistable states from which different types of flip-flop can be implemented is demonstrated. In this paper, some general comments are first presented on digital computing as applied to optics. This is followed by a discussion of optical implementation of various types of flip-flop. These flip-flops are then used in the design of optical equivalents to a few simple sequential circuits such as shift registers and accumulators. As a typical sequential machine, a schematic layout for an optical binary temporal integrator is presented. Finally, a suggested experimental configuration for an optical master-slave flip-flop array is given.

Fatehi, M. T.↗
NASA NTRS1984

Space station - The next logical step

NASA has been charged with the development, over the next decade, of a permanently manned space station in low earth orbit. The space station system will comprise a manned base and associated unmanned platforms; while one of the platforms will be in polar orbit, another (or several) platforms will, like the manned base, have an orbital inclination of 28.5 deg. Because it is permanent, the space station will have to be semiautonomous from its mission control center. NASA will take a number of steps to foster the commercial utilization of the space station, and one of the design goals of the project is the definition of astronaut facilities that are very 'customer friendly'. Reliance on a single, program-wide contractor has been deemed undesirable; several major aerospace manufacturers will instead distribute responsibility among themselves for the various modules constituting the craft.

Beggs, J. M.↗
NASA NTRS1985

Spacestation: The next logical step

The concept of a U.S. space station is discussed. The design, how it will work, space laboratory functions, commerce in space, and international cooperation are discussed.

Source record↗
NASA NTRS1983

Communications and logic systems at millimeter wave frequencies

Activities in materials development, lithography, FET experiments, and mixer diode fabrication are reported. In addition, articles are presented which address leakage effects in n-GaAs MESFET's and lateral nonuniform doping in GaAs MESFET's.

Source record↗
NASA NTRS1983

Communications and logic systems at millimeter wave frequencies, summary

During the contract period an AsCl3 epitaxial system used to provide buffer layers for FET structures was constructed. A submicron lithographic processes using deep U.V. techniques was developed and, employing these techniques, a working .5 micron gate device was produced. In addition, the development of submicron mixer diodes continued. The gettering of substrates of a technique to improve the mobility of ionimplantated layers was investigated. The result of this experiment showed a correlation between improved hall mobilities and gettered substrates. Finally, several theoretical studies are reported.

Source record↗
NASA NTRS1985

A formalization of commonsense reasoning based on fuzzy logic

The basic idea underlying the approach outlined in this paper is that commonsense knowledge may be regarded as a collection of dispositions, that is, propositions which are preponderantly, but not necessarily always, true. Technically, a disposition may be interpreted as a proposition with implicit fuzzy quantifiers, e.g., most, almost all, usually, often, etc. For example, a disposition such as Swedes are blond may be interpreted as most Swedes are blond. For purposes of inference from commonsense knowledge, the conversion of a disposition into a proposition with explicit fuzzy quantifiers sets the stage for an application of syllogistic reasoning in which the premises are allowed to be of the form Q A's are B's, where A and B are fuzzy predicates and Q is a fuzzy quantifier. In general, the conclusion yielded by such reasoning is a proposition which may be converted into a disposition through the suppression of fuzzy quantifiers.

Zadeh, L. A.↗
NASA NTRS1984

Space Station - The next logical step

NASA is committed to the development of a permanently manned Space Station within a decade, in concert with European and Japanese space agencies. In addition to continuing scientific research, the Space Station will proceed with applied science and industrialization experiments. International cooperation opportunities arise within the Space Station program for users (in the definition of missions), for builders (in the development of station resources and capabilities), and operators (in the orbital maintenance of the Space Station).

Finn, T. T.↗