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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

MT's algorithm: A new algorithm to search for the optimum set of modulation indices for simultaneous range, command, and telemetry

MT's algorithm was developed as an aid in the design of space telecommunications systems when utilized with simultaneous range/command/telemetry operations. This algorithm provides selection of modulation indices for: (1) suppression of undesired signals to achieve desired link performance margins and/or to allow for a specified performance degradation in the data channel (command/telemetry) due to the presence of undesired signals (interferers); and (2) optimum power division between the carrier, the range, and the data channel. A software program using this algorithm was developed for use with MathCAD software. This software program, called the MT program, provides the computation of optimum modulation indices for all possible cases that are recommended by the Consultative Committee on Space Data System (CCSDS) (with emphasis on the squarewave, NASA/JPL ranging system).

Nguyen, Tien Manh↗

Detection of earth-approaching asteroids in near real time

Computer software, called the Moving Object Detection Program (MODP), is described which detects earth-approaching asteroids in near real time. The software runs on a workstation linked to the output of the drift-scanning CCD camera of the Spacewatch Telescope. MOPD recognizes trailed images, detects motion, and accurately determines angular positions and rates of motion for moving objects in the scan images. The results are obtained a few seconds after the image signals are shifted out of the CCD. During 2 months of trial observations with this system, 304 asteroids were detected down to a limiting apparent magnitude for untrailed images of V = 20.5.

Rabinowitz, D. L.↗

General-Purpose Graphics-Library Program

NASA Device Independent Graphics Library (NASADIG) computer program is general-purpose graphics-library program for use with many computer-based-engineering and management application programs. Software offers many features providing user with flexibility in creating graphics. Includes two- and three-dimensional plotting, splines and polynomial interpolation, area blanking control, multiple log/linear axes, legends and text control, curve-thickness control, and multiple text fonts. Written in ANSI FORTRAN 77.

Rogers, Joseph E.↗

Caesy: A software tool for computer-aided engineering

A new software tool, Caesy, is described. This tool provides a strongly typed programming environment for research in the development of algorithms and software for computer-aided control system design. A description of the user language and its implementation as they currently stand are presented along with a description of work in progress and areas of future work.

Wette, Matt↗

Program Computes Receiver Gain And Noise Profiles

RCVRPROF computer program is computer-aided-design (CAD) software tool useful in analysis and design of communication receivers and downconverters. Provides customized spreadsheet with formulas and graphs providing detailed description of performance of receiver. Such performance parameters as noise temperature, gain, noise power, noise spectral density, and dynamic range analyzed for contribution of each to overall performance of receiver.

Mcwatters, Dalia↗

NASA Tech Briefs, March 2002

Topics include: a special section on data acquisition, software, electronic components and systems, materials, computer programs, mechanics, machinery/automation, manufacturing, biomedical, physical sciences, book and reports, and a special section of Photonics Tech Briefs.

Source record↗

Personal Computer Transport Analysis Program

The Personal Computer Transport Analysis Program (PCTAP) is C++ software used for analysis of thermal fluid systems. The program predicts thermal fluid system and component transients. The output consists of temperatures, flow rates, pressures, delta pressures, tank quantities, and gas quantities in the air, along with air scrubbing component performance. PCTAP s solution process assumes that the tubes in the system are well insulated so that only the heat transfer between fluid and tube wall and between adjacent tubes is modeled. The system described in the model file is broken down into its individual components; i.e., tubes, cold plates, heat exchangers, etc. A solution vector is built from the components and a flow is then simulated with fluid being transferred from one component to the next. The solution vector of components in the model file is built at the initiation of the run. This solution vector is simply a list of components in the order of their inlet dependency on other components. The component parameters are updated in the order in which they appear in the list at every time step. Once the solution vectors have been determined, PCTAP cycles through the components in the solution vector, executing their outlet function for each time-step increment.

DiStefano, Frank, III↗

Automated Counting of Particles To Quantify Cleanliness

A machine vision system, similar to systems used in microbiological laboratories to count cultured microbes, has been proposed for quantifying the cleanliness of nominally precisely cleaned hardware by counting residual contaminant particles. The system would include a microscope equipped with an electronic camera and circuitry to digitize the camera output, a personal computer programmed with machine-vision and interface software, and digital storage media. A filter pad, through which had been aspirated solvent from rinsing the hardware in question, would be placed on the microscope stage. A high-resolution image of the filter pad would be recorded. The computer would analyze the image and present a histogram of sizes of particles on the filter. On the basis of the histogram and a measure of the desired level of cleanliness, the hardware would be accepted or rejected. If the hardware were accepted, the image would be saved, along with other information, as a quality record. If the hardware were rejected, the histogram and ancillary information would be recorded for analysis of trends. The software would perceive particles that are too large or too numerous to meet a specified particle-distribution profile. Anomalous particles or fibrous material would be flagged for inspection.

Rhode, James↗

Stellar Photometry Software

We describe the Stellar Photometry Software (SPS), which combines in a single program procedures for locating stars, computing a mean stellar point-spread function (PSF), and performing aperture and/or multiple PSF-fitting photometry, along with related bookkeeping functions. The software can be run either interactively or in batch mode on computers using the UNIX operating system. The performance of SPS is compared to that of the photometry programs DoPHOT and IRAF/DAOPHOT, using both real and simulated CCD observations. A direct comparison of the instrumental magnitudes shows that all three programs produce comparable results.

Janes, Kenneth A.↗

Software engineering of a navigation and guidance system for commercial aircraft

The avionics experimental configuration of the considered system is briefly reviewed, taking into account the concept of an advanced air traffic management system, flight critical and noncritical functions, and display system characteristics. Cockpit displays and the navigation computer are examined. Attention is given to the functions performed in the navigation computer, major programs in the navigation computer, and questions of software development.

Lachmann, S. G.↗

Flight Dynamics Analysis System

Flight Dynamics Analysis System (FDAS) collection of computer programs provides environment for configuration and study of Ada software. Designed to support flight-dynamics research and analysis activities concerning software models, algorithms, and techniques used within flight Dynamics Division at Goddard Space Flight Center. Assists analysts and programmers in building, testing, and evaluating applications software by providing integrated support system for modification and reconfiguration of software. Includes capability of assembling reusable software components into applications programs, and reconfiguring assembled program after partially or fully completed. Developed in Ada for use on DEC VAX computer operating under VMS 4.3 or higher and version 1.3 or higher of VAX Ada Compilation System (ACS).

Tasaki, Keiji↗

Parallel line analysis: multifunctional software for the biomedical sciences

An easy to use, interactive FORTRAN program for analyzing the results of parallel line assays is described. The program is menu driven and consists of five major components: data entry, data editing, manual analysis, manual plotting, and automatic analysis and plotting. Data can be entered from the terminal or from previously created data files. The data editing portion of the program is used to inspect and modify data and to statistically identify outliers. The manual analysis component is used to test the assumptions necessary for parallel line assays using analysis of covariance techniques and to determine potency ratios with confidence limits. The manual plotting component provides a graphic display of the data on the terminal screen or on a standard line printer. The automatic portion runs through multiple analyses without operator input. Data may be saved in a special file to expedite input at a future time.

NASA Discipline Cell Biology↗

Evaluation of verification and testing tools for FORTRAN programs

Two automated software verification and testing systems were developed for use in the analysis of computer programs. An evaluation of the static analyzer DAVE and the dynamic analyzer PET, which are used in the analysis of FORTRAN programs on Control Data (CDC) computers, are described. Both systems were found to be effective and complementary, and are recommended for use in testing FORTRAN programs.

Smith, K. A.↗

Software Aids Visualization of Computed Unsteady Flow

Unsteady Flow Analysis Toolkit (UFAT) is a computer program that synthesizes motions of time-dependent flows represented by very large sets of data generated in computational fluid dynamics simulations. Prior to the development of UFAT, it was necessary to rely on static, single-snapshot depictions of time-dependent flows generated by flow-visualization software designed for steady flows. Whereas it typically takes weeks to analyze the results of a largescale unsteady-flow simulation by use of steady-flow visualization software, the analysis time is reduced to hours when UFAT is used. UFAT can be used to generate graphical objects of flow visualization results using multi-block curvilinear grids in the format of a previously developed NASA data-visualization program, PLOT3D. These graphical objects can be rendered using FAST, another popular flow visualization software developed at NASA. Flow-visualization techniques that can be exploited by use of UFAT include time-dependent tracking of particles, detection of vortex cores, extractions of stream ribbons and surfaces, and tetrahedral decomposition for optimal particle tracking. Unique computational features of UFAT include capabilities for automatic (batch) processing, restart, memory mapping, and parallel processing. These capabilities significantly reduce analysis time and storage requirements, relative to those of prior flow-visualization software. UFAT can be executed on a variety of supercomputers.

Kao, David↗

An Object-Oriented Approach to Writing Computational Electromagnetics Codes

Presently, most computer software development in the Computational Electromagnetics (CEM) community employs the structured programming paradigm, particularly using the Fortran language. Other segments of the software community began switching to an Object-Oriented Programming (OOP) paradigm in recent years to help ease design and development of highly complex codes. This paper examines design of a time-domain numerical analysis CEM code using the OOP paradigm, comparing OOP code and structured programming code in terms of software maintenance, portability, flexibility, and speed.

Zimmerman, Martin↗

Software Computes Tape-Casting Parameters

Tcast2 is a FORTRAN computer program that accelerates the setup of a process in which a slurry containing metal particles and a polymeric binder is cast, to a thickness regulated by a doctor blade, onto fibers wound on a rotating drum to make a green precursor of a metal-matrix/fiber composite tape. Before Tcast2, setup parameters were determined by trial and error in time-consuming multiple iterations of the process. In Tcast2, the fiber architecture in the final composite is expressed in terms of the lateral distance between fibers and the thickness-wise distance between fibers in adjacent plies. The lateral distance is controlled via the manner of winding. The interply spacing is controlled via the characteristics of the slurry and the doctor-blade height. When a new combination of fibers and slurry is first cast and dried to a green tape, the shrinkage from the wet to the green condition and a few other key parameters of the green tape are measured. These parameters are provided as input to Tcast2, which uses them to compute the doctor-blade height and fiber spacings needed to obtain the desired fiber architecture and fiber volume fraction in the final composite.

deGroh, Henry C., III↗

COSMIC: Software catalog 1991 edition diskette format

The PC edition of the annual COSMIC Software contains descriptions of the over 1,200 computer programs available for use within the United States as of January 1, 1991. By using the PC version of the catalog, it is possible to conduct extensive searches of the software inventory for programs that meet specific criteria. Elements such as program keywords, hardware specifications, source code languages, and title acronyms can be used for the basis of such searches. After isolating those programs that might be of best interest to the user, it is then possible to either view at the monitor, or generate a hardcopy listing of all information on those packages. In addition to the program elements that the user can search on, information such as total program size, distribution media, and program price, as well as extensive abstracts on the program, are also available to the user at this time. Another useful feature of the catalog allows for the retention of programs that meet certain search criteria between individual sessions of using the catalog. This allows users to save the information on those programs that are of interest to them in different areas of application. They can then recall a specific collection of programs for information retrieval or further search reduction if desired. In addition, this version of the catalog is adaptable to a network/shared resource environment, allowing multiple users access to a single copy of the catalog database simultaneously.

Source record↗

Program Computes Performances Of Scramjets

SRGULL, a scramjet-cycle-analysis computer code, engineer's software tool capable of nose-to-tail simulation of hydrogen-fueled, scramjet engine integrated with air-frame. Simulated flow that of real gas with equilibrium thermodynamic properties. Program facilities initial estimates of performance of scramjet cycle by linking code for two-dimensional forebody, inlet, and nozzle with code for one-dimensional combustor. Five computer codes (SCRAM, SEAGUL, INLET, Program HUD, and GASH) integrated in program to provide capability for analysis of changing flow conditions. Written in FORTRAN 77.

Walton, J. T.↗