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The IUE archives are described as well as their applications and possible future developments. The data for each image is archived as a set usually containing a raw image, a processed image, and one or more extracted spectra. A cumulative plot of the number of images which have been retrieved from the IUE archives is provided, indicating that interest in the data continues to grow in all of the astronomical communities served.
The major difficulty in stereo vision is the correspondence problem that requires matching features in two stereo images. Researchers describe a constraint-based stereo matching technique using local geometric constraints among edge segments to limit the search space and to resolve matching ambiguity. Edge segments are used as image features for stereo matching. Epipolar constraint and individual edge properties are used to determine possible initial matches between edge segments in a stereo image pair. Local edge geometric attributes such as continuity, junction structure, and edge neighborhood relations are used as constraints to guide the stereo matching process. The result is a locally consistent set of edge segment correspondences between stereo images. These locally consistent matches are used to generate higher-level hypotheses on extended edge segments and junctions to form more global contexts to achieve global consistency.
An approach is presented to the control of a dynamic physical system through the use of approximate reasoning. The approach has been implemented in a program named POLE, and the authors have successfully built a prototype hardware system to solve the cartpole balancing problem in real-time. The approach provides a complementary alternative to the conventional analytical control methodology and is of substantial use when a precise mathematical model of the process being controlled is not available. A set of criteria for comparing controllers based on approximate reasoning and those based on conventional control schemes is furnished.
High T(sub c) superconducting thin and thick films have potential applications in future NASA flight projects. In anticipation of film use, the Materials Branch is developing a nondestructive, non-contact method of measuring the spatial variation of conductivity across a film sample. This method uses a computer-controlled, X-Y positioning table to scan a conventional eddy current probe across the surface of a film. The induced changes in impedance caused by variations in film conductivity are recorded during the scanning process. Ultimately the two-dimensional data set is displayed using imaging equipment on a personal computer.
Documented here are papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by NASA and the University of Texas, Houston. Topics addressed included adaptive systems, learning algorithms, network architectures, vision, robotics, neurobiological connections, speech recognition and synthesis, fuzzy set theory and application, control and dynamics processing, space applications, fuzzy logic and neural network computers, approximate reasoning, and multiobject decision making.
Documented here are papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by NASA and the University of Houston, Clear Lake. The workshop was held April 11 to 13 at the Johnson Space Flight Center. Technical topics addressed included adaptive systems, learning algorithms, network architectures, vision, robotics, neurobiological connections, speech recognition and synthesis, fuzzy set theory and application, control and dynamics processing, space applications, fuzzy logic and neural network computers, approximate reasoning, and multiobject decision making.
The MODEL III variational data assimilation model is the third of four general assimilation models designed to blend weather data measured from space based platforms in the meteorological data mainstream in a way that maximizes the information content of the satellite data. Because there are many different observation locations and there are many instruments with different measurement error characteristics, it is also necessary to require that the blending be done to maximize the information content of the data and simultaneously to retain a dynamically consistent and reasonably accurate description of the state of the atmosphere. This is ideally a variational problem for which the data receive relative weights that are inversely proportional to measurement error and are adjusted to satisfy a set of dynamical equations that govern atmospheric processes. The advantage of MODEL III over the previous two models is that radiance, the atmospheric variable measured by satellite, becomes a dependent variable. In the previous versions, mean layer temperatures that had been retrieved from the radiances by some method, were included in the assimilation by substituting them in place of the rawinsonde temperatures. Now both rawinsonde temperatures and satellite radiances are included independently in the assimilation.
The research supported by the NASA ADP contract NAG5-1153 has been completed. The attached paper, which will be submitted for publication in the Astrophysical Journal in January 1992, presents the results of this work. Here is a summary of the project and its results. A set of computer programs was developed to process the raw 60 micron and 100 micron IRAS survey data. The programs were designed to detect faint extended emission surrounding a bright unresolved source. Candidate objects were chosen from a list of red giant stars and young planetary nebulae which have been detected in millimeter/submillimeter lines of CO. Of the 279 stars examined, 55 were resolved at 60 microns. The principle results of the study are given. The average age for the shells surrounding the 9 Mira-type stars which are extended is 6 x 10(exp 4) yr. This suggests that the period during which these stars lose mass lasts for approx 10(exp 5) yr. The oldest shell found surrounds U Ori, and the youngest surrounds Mira itself. Some shells appear to be detached from the central star. This phenomenon is more common among older stars, suggesting that the mass loss becomes more episodic as the star sheds its envelope. Although all 8 stars less distant than 200 pc are resolved in the IRAS 60 micron data, 29 stars within 500 pc were not. These stars probably have younger circumstellar shells than those which were resolved. Almost all the carbon stars with distances of 500 pc or less have resolved shells, while only 1/2 of the oxygen-rich stars do. The resolved carbon star shells also are older on average than the oxygen-rich ones. These facts imply that carbon stars have been losing mass for a longer period, on average, than oxygen-rich red giants. Large circumstellar shells tend to be found at large distances from the galactic plane, confirming that the ISM density limits the size to which a dust shell can grow. Surprisingly, even very large shells seem to be nearly spherical, and do not appear to be distorted by ram-pressure caused by the star's motion with respect to the ISM. Radiative transfer models and the value of I sub 60 microns/I sub 100 microns allow the average dust temperature in the outer regions of a circumstellar shell to be estimated. The typical value obtained in about 35 K.
QX MAN is a grid and solution file manipulation program written primarily for the PARC code and the GRIDGEN family of grid generation codes. QX MAN combines many of the features frequently encountered in grid generation, grid refinement, the setting-up of initial conditions, and post processing. QX MAN allows the user to manipulate single block and multi-block grids (and their accompanying solution files) by splitting, concatenating, rotating, translating, re-scaling, and stripping or adding points. In addition, QX MAN can be used to generate an initial solution file for the PARC code. The code was written to provide several formats for input and output in order for it to be useful in a broad spectrum of applications.
The primary mechanism by which dust is inserted into the Martian atmosphere is the interaction of low-level atmospheric motions with the planet's surface. Near-surface winds exert a shear stress upon dust particles resting on the Martian surface, and at some lower threshold limit of stress magnitude, approximately 0.04 N-m(exp -2), particles are set into motion. Wind tunnel studies indicate that the first particles are too large to remain in suspension in the Martian atmosphere, but their impact back upon the surface can set smaller suspendable particles into motion. This process is termed saltation. Numerical simulations of Martian dust storms were carried out via the interactive coupling of the NASA Ames Mars general circulation Model with an aerosol transport/microphysical model.
A group of knowledgeable scientists and engineers in New Mexico has recognized the need for such a testing capability and has proposed a project to evelop an extraterrestrial surface simulation facility. A group of universities, national laboratories, and private industrial firms is proposing to establish a Center for Extraterrestrial Engineering and Construction (CETEC) and to develop large extraterrestrial surface simulation facilities in which this needed testing can be realistically performed. The CETEC is envisioned to be both a center of knowledge and data regarding engineering, construction, mining, and material process operations on extraterrestrial bodies and a set of extraterrestrial surface simulation facilities. The primary CETEC facility is proposed to be a large domed building made of steel reinforced concrete with more than one acre of test floor area covered with several feet of simulated lunar soil and dust. Various aspects of the project are presented in viewgraph form.
TAWFIVE computer program calculates transonic flow over transport-type wing and fuselage. Combines multigrid acceleration technique in iterative solution of potential equation with use of integral-form boundary-layer equations to provide software tool computationally efficient, yet accurate enough for use in design. Simplifies solution process by breaking problem into loosely coupled set of modified equations. Inviscid-flow method, using standard inviscid-flow equations, valid in "outer" region away from wing, whereas boundary-layer equations valid in thin region near solid surface of wing. Written in FORTRAN 77.
Papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by the National Aeronautics and Space Administration and cosponsored by the University of Houston, Clear Lake, held 1-3 Jun. 1992 at the Lyndon B. Johnson Space Center in Houston, Texas are included. During the three days approximately 50 papers were presented. Technical topics addressed included adaptive systems; learning algorithms; network architectures; vision; robotics; neurobiological connections; speech recognition and synthesis; fuzzy set theory and application, control and dynamics processing; space applications; fuzzy logic and neural network computers; approximate reasoning; and multiobject decision making.
Documented here are papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by the National Aeronautics and Space Administration and cosponsored by the University of Houston, Clear Lake. The workshop was held June 1-3, 1992 at the Lyndon B. Johnson Space Center in Houston, Texas. During the three days approximately 50 papers were presented. Technical topics addressed included adaptive systems; learning algorithms; network architectures; vision; robotics; neurobiological connections; speech recognition and synthesis; fuzzy set theory and application, control, and dynamics processing; space applications; fuzzy logic and neural network computers; approximate reasoning; and multiobject decision making.
The NSF's Antarctic Research Center (ARC) has been established to furnish real-time polar-orbiting satellite data in support of Antarctic field studies, as well as to maintain a multisensor satellite data (MSD) archive for retrospective data analysis. An account is presently given of the ways in which the complementary nature of an MSD set can deepen understanding of Antarctic physical processes. An active microwave SAR with 30-m resolution and a radar altimeter will be added to the ARC resources later in this decade, as will the Earth Observing System.
Galileo's Solid-State Imaging (SSI) experiment acquired about 800 images of the Moon from the second Earth-Moon flyby (EM2) in December of 1992. Ten major sequences were acquired; each consists of mosaics of the entire or nearly entire visible and illuminated surface from each viewing geometry in at least six spectral filters (effective wavelengths for the Moon of 420, 564, 660, 756, 890, and 990 nm). The geometries of LUNMOS numbers 3, 4, 5, and 6 were designed to provide stereo data at the best possible resolutions. The purpose of this abstract is to describe the sequences, calibration, processing, and mosaicking, and to present a set of color products in a poster session.
There is a necessity of having an automatic procedure for reliable estimation of the quality of the measurement of particle size from QELS (Quasi-Elastic Light Scattering). Getting the measurement itself, before any error estimates can be made, is a problem because it is obtained by a very indirect measurement of a signal derived from the motion of particles in the system and requires the solution of an inverse problem. The eigenvalue structure of the transform that generates the signal is such that an arbitrarily small amount of noise can obliterate parts of any practical inversion spectrum. This project uses the Maximum Likelihood Estimation (MLE) as a framework to generate a theory and a functioning set of software to oversee the measurement process and extract the particle size information, while at the same time providing error estimates for those measurements. The theory involved verifying a correct form of the covariance matrix for the noise on the measurement and then estimating particle size parameters using a modified histogram approach.
The purpose of this study is to develop a standard method for measuring modal abundances of glass in single agglutinates in the lunar regolith. Not only does agglutinitic glass increase in single agglutinates as clasts of older agglutinates get incorporated into newer agglutinates with increasing maturity, but it is in this glassy phase that nanophase superparamagnetic Fe metal originates as a result of reduction reactions during the agglutination process. We report the results of two sets of independent measurements using two different methods to determine the proportion of glass in single agglutinates. We have used polished grain mounts (PGM) of five hand-picked single agglutinates from Apollo 16 soil 61181. The ISI Scanning Electron Microscope (SEM) fitted with a high-resolution Backscattered Electron (BSE) detector was used to collect high-contrast BSE images of the agglutinates. Several images were collected to represent each single agglutinate. The contrast, brightness, and focus were adjusted to optimize each image collected. Histograms of the grayscale range for all images produced four 'peaks' corresponding to epoxy, glass, crystalline phases, and metal grains. We analyzed every grid point for 12 elements with a less than 1 micron electron beam using a CAMECA SX-50 electron probe microanalyzer (EPM). If any analysis was not within about 10% of the stoichiometry of a known lunar mineral, we considered that point to be nonmineralic. Our results show that there is a remarkable correspondence in the glass percentages obtained by the two methods. The EPM method may overestimate glass because secondary fluorescence from dusty clasts in agglutinitic glass can give the appearance of nonmineralic targets. The BSE method may underestimate glass because the diversity of compositions of agglutinitic glass may not be contained under one grayscale 'peak' during image analysis.