Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “implementation”

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 1,153 records · Page 64
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Implementation of a C-1 triangular element based on the P-version of the finite element method

The implementation of a computer code CONE (for C(1) continuity) based on the p-version of the finite element method is described. A hierarchic family of triangular finite elements of degree p 5 is used. This family enforces C(1)-continuity across interelement boundaries, and the code is applicable to fourth order partial differential equations in two independent variables, in particular to the biharmonic equation. Applications to several benchmark problems in plate bending are presented. Sample results are examined and compared with theoretical predictions. In particular the analysis of the bending of a rhombic plate shows a significant improvement over othr published results.

Wang, D. W.↗
NASA NTRS1981

Analogue implementation of analytic signal processing for pulse-echo systems

An alternative to rectification is proposed for detection of an ultrasonic signal. This method is especially useful in medical and non-destructive evaluation (nde) applications. With this method, the magnitude of the complex analytic signal is used to define the envelope of the ultrasonic waveform. The square of this quantity has been shown elsewhere to be equal to the true rate-of-arrival of energy. An earlier study, using digital data processing, has already demonstrated the superior resolvability of closely spaced interfaces obtained with the analytic signal magnitude, as compared to conventional rectification. Here, an analogue implementation is presented which utilizes single-sideband techniques to obtain both quadrature components of the analytic signal and its magnitude. A conventional transducer, pulser, and receiver are used.

Gammell, P. M.↗
NASA NTRS1982

Development, implementation, and test results on integrated optics switching matrix

A small integrated optics switching matrix, which was developed, implemented, and tested, indicates high performance. The matrix serves as a model for the design of larger switching matrices. The larger integrated optics switching matrix should form the integral part of a switching center with high data rate throughput of up to 300 megabits per second. The switching matrix technique can accomplish the design goals of low crosstalk and low distortion. About 50 illustrations help explain and depict the many phases of the integrated optics switching matrix. Many equations used to explain and calculate the experimental data are also included.

Rutz, E.↗
NASA NTRS1982

FORTRAN implementation of Friedman's test for several related samples

The FRIEDMAN program is a FORTRAN-coded implementation of Friedman's nonparametric test for several related samples with one observation per treatment/-block combination, or as it is sometimes called, the two-way analysis of variance by ranks. The FRIEDMAN program is described and a test data set and its results are presented to aid potential users of this program.

Davidson, S. A.↗
NASA NTRS1980

Implementing an integrated engineering data base system: A developer's experience and the application to IPAD

The software developed by the IPAD project, a new and very powerful tool for the implementation of integrated Computer Aided Design (CAD) systems in the aerospace engineering community, is discussed. The IPAD software is a tool and, as such, can be well applied or misapplied in any particular environment. The many benefits of an integrated CAD system are well documented, but there are few such systems in existence, especially in the mechanical engineering disciplines, and therefore little available experience to guide the implementor.

Bruce, E. A.↗
NASA NTRS1983

Implementation of R & QA practices in Research and Development programs

DOE has established a number of broad programs aimed at reducing fuel consumption. Several programs address the R&D of ground transportation propulsion alternatives to the conventional spark-ignition engine. NASA Lewis is responsible for managing the effort between the Government and industry teams involving American and foreign companies. Thus, existing NASA SR&QA procedure were modified/adapted to these R&D programs and implemented to assure that the test hardware design intent was met, the hardware was not hazardous to personnel, it would demonstrate reliable operation, and it would help establish the future R&D quality assurance and maintainability requirements. This successful low-cost approach might be applicable to other similar projects.

Bankaitis, H.↗
NASA NTRS1983

A VLSI implementation of a multicode convolutional encoder

A VLSI architecture and layout for a convolutional encoder is described. This architecture allows a single chip implementation of an encoder that is capable of handling many different convolutional codes including all the convolutional codes that are presently used for deep space missions.

Deutsch, L. J.↗
NASA NTRS1980

Parallel processing implementations of a contextual classifier for multispectral remote sensing data

Contextual classifiers are being developed as a method to exploit the spatial/spectral context of a pixel to achieve accurate classification. Classification algorithms such as the contextual classifier typically require large amounts of computation time. One way to reduce the execution time of these tasks is through the use of parallelism. The applicability of the CDC flexible processor system and of a proposed multimicroprocessor system (PASM) for implementing contextual classifiers is examined.

Siegel, H. J.↗
NASA NTRS1983

Area navigation implementation for a microcomputer-based LORAN-C receiver

Engineering performed to make LORAN-C a more useful and practical navigation system for general aviation is described. Development of new software, and implementation of this software on a (MOS6502) microcomputer to provide high quality practical area navigation information directly to the pilot and considered. Flight tests were performed specifically to examine the efficacy of this new software. Final results were exceptionally good and clearly demonstrate the merits of this new LORAN-C area navigation system.

Oguri, F.↗
NASA NTRS1983

Experiment requirements and implementation plan (Erip) for semiconductor materials growth in low-G environment

The MEA-2 A facility was used to test the effect of the low gravity environment on suppressing convective mixing in the growth of Pb(1-x)Sn(x)Te crystals. The need to eliminate convection, the furnace characteristics and operation that will be required for successful experimental implementation, and to the level that is presently known, the measured physical properties of the Pb(1-x)Sn(x)Te system were discussed. In addition, a brief background of the present and potential utilization of Pb(1-x)Sn(x)Te is given. Additional experiments are anticipated in future MEA-A, improved MEA and other dedicated materials processing in space flight apparatus.

Crouch, R. K.↗
NASA NTRS1982

Implementation of the DAST ARW II control laws using an 8086 microprocessor and an 8087 floating-point coprocessor

A 5 MHZ single-board microprocessor system which incorporates an 8086 CPU and an 8087 Numeric Data Processor is used to implement the control laws for the NASA Drones for Aerodynamic and Structural Testing, Aeroelastic Research Wing II. The control laws program was executed in 7.02 msec, with initialization consuming 2.65 msec and the control law loop 4.38 msec. The software emulator execution times for these two tasks were 36.67 and 61.18, respectively, for a total of 97.68 msec. The space, weight and cost reductions achieved in the present, aircraft control application of this combination of a 16-bit microprocessor with an 80-bit floating point coprocessor may be obtainable in other real time control applications.

Kelly, G. L.↗
NASA NTRS1983

U.S. planetary protection program - Implementation highlights

The implementation of the United States planetary protection program, intended to prevent the contamination of the celestial bodies in the solar system during their exploration, in recent interplanetary projects is reviewed. The shift in planetary protection policy from that of absolute sterilization to a probabilistic approach is noted. Attention is then given to the use of microbiological assay, organic materials inventory, microbial burden reduction, contamination control, trajectory biasing and the analysis and identification of contaminating processes for purposed of planetary protection for the Pioneer 10 and 11, Viking and Voyager projects. The success of these measures, as demonstrated by the prevention of accidental planetary impact and the failure to detect terrestrial organisms by the Viking life detection experiments, is pointed out.

Barengoltz, J.↗
NASA NTRS1985

Software-Implementation Plan

Top-down implementation plan provides a methodology for solving problems in or aiding software engineering design.

Jacobson, G.↗
NASA NTRS1983

Design and implementation of a preprocessing system for a sodium lidar

A preprocessing system, designed and constructed for use with the University of Illinois sodium lidar system, was developed to increase the altitude resolution and range of the lidar system and also to decrease the processing burden of the main lidar computer. The preprocessing system hardware and the software required to implement the system are described. Some preliminary results of an airborne sodium lidar experiment conducted with the preprocessing system installed in the sodium lidar are presented.

Voelz, D. G.↗
NASA NTRS1983

A real-time implementation of an advanced sensor failure detection, isolation, and accommodation algorithm

A sensor failure detection, isolation, and accommodation algorithm was developed which incorporates analytic sensor redundancy through software. This algorithm was implemented in a high level language on a microprocessor based controls computer. Parallel processing and state-of-the-art 16-bit microprocessors are used along with efficient programming practices to achieve real-time operation.

Delaat, J. C.↗
NASA NTRS1983

Implementation of elastic-plastic structural analysis into NASTRAN

Elastic-plastic analytic capabilities were incorporated into the NASTRAN program. The present implementation includes a general rigid format and additional bulk data cards as well as to two new modules. The modules are specialized to include only perfect plasticity of the CTRMEN and CROD elements but can easily be expanded to include other plasticity theories and elements. The practical problem of an elastic-plastic analysis of a ship's bracket connection is demonstrated and compared to an equivalent analysis using Grumman's PLANS program. The present work demonstrates the feasibility of incorporating general elastic-plastic capabilities into NASTRAN.

Levy, A.↗
NASA NTRS1984

Conceptual design and simulator implementation of an automatic terminal approach system

The pilot-machine interface with aircraft automation to increase the safety and utility of single-pilot IFR (instrument flight rules) operations is addressed. An automatic terminal approach system (ATAS), that uses stored instrument approach data to automatically tune aircraft radios and control the aircraft autopilot, was conceived as a means of improving this critical interface. The ATAS automatically flies instrument approach procedures, including the missed approach, and provides for easy pilot interaction to accommodate air traffic control radar vectors and altitude assignments. A research prototype of an ATAS was developed to the extent necessary for a simulation implementation and piloted evaluation. The development of the ATAS concept and the software algorithms is described.

Hinton, D. A.↗
NASA NTRS1984

Preliminary results in implementing a model of the world economy on the CYBER 205: A case of large sparse nonsymmetric linear equations

A brief description of the Model of the World Economy implemented at the Institute for Economic Analysis is presented, together with our experience in converting the software to vector code. For each time period, the model is reduced to a linear system of over 2000 variables. The matrix of coefficients has a bordered block diagonal structure, and we show how some of the matrix operations can be carried out on all diagonal blocks at once.

Szyld, D. B.↗