12,730 research outputs found
Evaluation of LANDSAT-4 TM and MSS ground geometry performance without ground control
Techniques and software developed to characterize the Washington, D.C. scene were improved and are being systematically applied to an Imperial Valley, CA scene. Digital elevation files are being acquired. One hundred seventy-two tiepoints were located in the Imperial Valley scene. They were digitized from USGS maps to determine their lat-long coordinates. A least squares fit is currently being performed between line-sample image data and the lat-long positions of the tiepoints. Thematic mapper scanner sweeps were determined for the Imperial Valley P-data. VICAR jobs are currently under way to analyze sample-direction offsets between sweeps in the data, as well as band to band registration offsets. Tiepoint location is about to begin in the Harrisburg, PA scene
Management of Forehead Scars
This article provides an overview of scar management within the forehead region. It addresses the unique challenges specific to the treatment of forehead wounds. A logical, stepwise approach is used. A subsite based treatment algorithm is provided along with a review of current best practices. Pertinent case examples are included for demonstration purposes
Processor Verification Using Efficient Reductions of the Logic of Uninterpreted Functions to Propositional Logic
The logic of equality with uninterpreted functions (EUF) provides a means of
abstracting the manipulation of data by a processor when verifying the
correctness of its control logic. By reducing formulas in this logic to
propositional formulas, we can apply Boolean methods such as Ordered Binary
Decision Diagrams (BDDs) and Boolean satisfiability checkers to perform the
verification.
We can exploit characteristics of the formulas describing the verification
conditions to greatly simplify the propositional formulas generated. In
particular, we exploit the property that many equations appear only in positive
form. We can therefore reduce the set of interpretations of the function
symbols that must be considered to prove that a formula is universally valid to
those that are ``maximally diverse.''
We present experimental results demonstrating the efficiency of this approach
when verifying pipelined processors using the method proposed by Burch and
Dill.Comment: 46 page
LUMIS Interactive graphics operating instructions and system specifications
The LUMIS program has designed an integrated geographic information system to assist program managers and planning groups in metropolitan regions. Described is the system designed to interactively interrogate a data base, display graphically a portion of the region enclosed in the data base, and perform cross tabulations of variables within each city block, block group, or census tract. The system is designed to interface with U. S. Census DIME file technology, but can accept alternative districting conventions. The system is described on three levels: (1) introduction to the systems's concept and potential applications; (2) the method of operating the system on an interactive terminal; and (3) a detailed system specification for computer facility personnel
Optical/Infrared Observations of the Anomalous X-ray Pulsar 1E 1048.1-5937 During Its 2007 X-Ray Flare
We report on optical and infrared observations of the anomalous X-ray pulsar
(AXP) 1E 1048.1-5937, made during its ongoing X-ray flare which started in 2007
March. We detected the source in the optical I and near-infrared Ks bands in
two ground-based observations and obtained deep flux upper limits from four
observations, including one with the Spitzer Space Telescope at 4.5 and 8.0
microns. The detections indicate that the source was approximately 1.3--1.6
magnitudes brighter than in 2003--2006, when it was at the tail of a previous
similar X-ray flare. Similar related flux variations have been seen in two
other AXPs during their X-ray outbursts, suggesting common behavior for large
X-ray flux variation events in AXPs. The Spitzer flux 1E 1048.1-5937 limits are
sufficiently deep that we can exclude mid-infrared emission similar to that
from the AXP 4U 0142+61, which has been interpreted as arising from a dust disk
around the AXP. The optical/near-infrared emission from probably has a
magnetospheric origin. The similarity in the flux spectra of 4U 0142+61 and 1E
1048.1-5937 challenges the dust disk model proposed for the latter.Comment: 5 pages, 1 figure, accepted by Ap
Geographic science team
The rational for using remote sensing in land use/land cover, geomorphology, and cartography applications is stated as well as potential uses in each of these areas. The next step to be perfected is indicated. Spatial and spectral resolution requirements for photointerpretations and/or multispectral pattern recognition of geomorphic elements and of cultural surface cover are listed. Requirements for photographic/analog or digital photogrammetry from spaceborne multispectral linear array sensors are included. A prioritized summary of data gaps in the geographic sciences is included
Proceedings of the NASA Workshop on Registration and Rectification
Issues associated with the registration and rectification of remotely sensed data. Near and long range applications research tasks and some medium range technology augmentation research areas are recommended. Image sharpness, feature extraction, inter-image mapping, error analysis, and verification methods are addressed
Urban solar photovoltaics potential: An inventory and modelling study applied to the San Fernando Valley region of Los Angeles
Procedures for analyzing the potential of solar photovoltaic collectors to meet energy requirements in a metropolitan region are described and a modeling effort is applied to the San Fernando Valley region of Los Angeles. The procedure involves a series of steps designed to produce maps and tabulations revealing the amount of rooftop area available for establishing solar collectors and the proportion of energy requirement that could be potentially supplied by solar photovoltaics within each of the 533 mainline feeder service areas in the study area. For the sixty five square mile study area, the results showed that, with half the available flat and south facing roofs used and assuming the availability of energy storage, 52.7 percent of the actual kWh energy requirements could have been met in 1978 using photovoltaic collectors. Hourly, daily, weekly, and monthly fluctuations in potential supply and actual loads and recommendations of avenues for further research are discussed. Some further potential applications of the modeling technique are suggested
Integrable vortex-type equations on the two-sphere
We consider the Yang-Mills instanton equations on the four-dimensional
manifold S^2xSigma, where Sigma is a compact Riemann surface of genus g>1 or
its covering space H^2=SU(1,1)/U(1). Introducing a natural ansatz for the gauge
potential, we reduce the instanton equations on S^2xSigma to vortex-type
equations on the sphere S^2. It is shown that when the scalar curvature of the
manifold S^2xSigma vanishes, the vortex-type equations are integrable, i.e. can
be obtained as compatibility conditions of two linear equations (Lax pair)
which are written down explicitly. Thus, the standard methods of integrable
systems can be applied for constructing their solutions. However, even if the
scalar curvature of S^2xSigma does not vanish, the vortex equations are well
defined and have solutions for any values of the topological charge N. We show
that any solution to the vortex equations on S^2 with a fixed topological
charge N corresponds to a Yang-Mills instanton on S^2xSigma of charge (g-1)N.Comment: 14 pages; v2: clarifying comments added, published versio
Marx in Miami: Reflections on Teaching and the Confrontation with Ideology
In composing this piece we hope to detail some of our strategies and pedagogical experiences teaching Marx and Marxism in Miami, Florida. Although Miami is certainly a special case regarding the intensity and character of ideological fervor against Leftist political and social theory, we believe the lessons adapted to this specific environment can be generalized for instructors regardless of geography. Teaching Marx in the United States often poses unique challenges. In Miami, those obstacles feel frequently amplified
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