Institution
Computer Sciences Corporation
About: Computer Sciences Corporation is a based out in . It is known for research contribution in the topics: Spacecraft & Software development. The organization has 1916 authors who have published 2389 publications receiving 62729 citations. The organization is also known as: CSC.
Topics: Spacecraft, Software development, Stars, Software, Software construction
Papers published on a yearly basis
Papers
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29 Jun 2000TL;DR: In this article, an improved method and system for logging transaction records in a computer system was proposed, where the unload program may write transaction log records accompanied by a confirmation log record to a good output file.
Abstract: An improved method and system for logging transaction records in a computer system. The method may include writing a confirmation log record to the log file for a transaction that completes normally, and not writing a confirmation log record for transactions that are aborted. The log file may be unloaded periodically by an unload program. The unload program may write transaction log records accompanied by a confirmation log record to a good output file and transaction log records not accompanied by a confirmation log record to a suspended output file. On a subsequent execution, the unload program may combine the log records in the log file and the suspended file. The unload program may write transaction log records accompanied by a confirmation log record to a good output file. The unload program may write transaction log records not accompanied by a confirmation log record and which have not exceeded a transaction time limit to a suspended output file. The unload program may write transaction log records not accompanied by a confirmation log record and which have exceeded a transaction time limit to a disposal output file. The transaction log records in the good output file may then be processed normally by log processing programs.
73 citations
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TL;DR: In this paper, the authors formulate and use information and fidelity criteria to assess image gathering and processing, combining optical design with image-forming and edge-detection algorithms, and combine the informationally optimized design with a 3 by 3 lateral-inhibitory image-plane-processing algorithm leads to a spatial-response shape that approximates the optimal edge detection response of human vision and thus reduces the data preprocessing and transmission required for machine vision.
Abstract: In this paper we formulate and use information and fidelity criteria to assess image gathering and processing, combining optical design with image-forming and edge-detection algorithms. The optical design of the image-gathering system revolves around the relationship among sampling passband, spatial response, and signal-to-noise ratio (SNR). Our formulations of information, fidelity, and optimal (Wiener) restoration account for the insufficient sampling (i.e., aliasing) common in image gathering as well as for the blurring and noise that conventional formulations account for. Performance analyses and simulations for ordinary optical-design constraints and random scences indicate that (1) different image-forming algorithms prefer different optical designs; (2) informationally optimized designs maximize the robustness of optimal image restorations and lead to the highest-spatial-frequency channel (relative to the sampling passband) for which edge detection is reliable (if the SNR is sufficiently high); and (3) combining the informationally optimized design with a 3 by 3 lateral-inhibitory image-plane-processing algorithm leads to a spatial-response shape that approximates the optimal edge-detection response of (Marr's model of) human vision and thus reduces the data preprocessing and transmission required for machine vision.
72 citations
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TL;DR: In this paper, a method of conversion of the lunar neutron counting rate measured by the Lunar Reconnaissance Orbiter (LRO) Lunar Exploration Neutron Detector (LEND) instrument collimated neutron detectors, to water equivalent hydrogen (WEH) in the top ∼1m layer of lunar regolith is presented.
71 citations
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TL;DR: In this article, additional data obtained from the Apollo 16 and Apollo 17 missions, together with collateral calculations on background radiation effects, have made possible an improved subtraction of unwanted backgrounds from the diffuse cosmic gamma-ray data previously reported from Apollo 15.
Abstract: Additional data obtained from the Apollo 16 and Apollo 17 missions, together with collateral calculations on background radiation effects, have made possible an improved subtraction of unwanted backgrounds from the diffuse cosmic gamma-ray data previously reported from Apollo 15. As a result, the 1- to 10-MeV spectrum is lowered significantly and connects smoothly with recent data at other energies. The inflection reported previously is much less pronounced and has no more than a 1.5-sigma significance. Sky occultation by the Apollo 16 spacecraft shows the bulk of the 0.3- to 1-MeV radiation to be diffuse. The analysis of spurious backgrounds points to important improvements for future experiments designed for this spectral region.
71 citations
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TL;DR: In this article, a model for simulating the remotely sensed microwave brightness temperatures of soils with rough surfaces is developed, where the surface emissivity of the soil media is calculated from one minus its reflectivity, which is obtained by the integration of the bistatic scattering coefficients for rough soil surfaces.
Abstract: A model for simulating the remotely sensed microwave brightness temperatures of soils with rough surfaces is developed. The surface emissivity of the soil media is calculated from one minus its reflectivity, which is obtained by the integration of the bistatic scattering coefficients for rough soil surfaces. The soil brightness temperature is obtained from the product of the surface emissivity and the effective soil temperature, which is calculated with measured soil moisture profiles and soil temperature profiles at various soil depths. The roughness of a soil surface is characterized by two parameters, the surface height standard deviation a and its horizontal correlation length l. The model calculations are compared to the measured angular variations of the polarized brightness temperatures at both L-band (1.4 GHz) and C-band (5 GHz) frequencies. A nonlinear least squares fitting method is used to match the model calculations with the data, and the best fit results produce the parameter values of a and l that best characterize the surface roughness. The effect of rough surface shadowing is also incorporated into the model by introducing a shadowing function S(?), which represents the probability that a point on a rough surface is not shadowed by other parts of the surface. The model results for horizontal polarization are in excellent agreement with the data, both qualitatively and quantitatively. For vertical polarization, some discrepancies exist between the calculations and data. Possible causes of the discrepancy are discussed.
71 citations
Authors
Showing all 1916 results
Name | H-index | Papers | Citations |
---|---|---|---|
David S. Ellsworth | 80 | 207 | 28072 |
Andrew A. Lacis | 73 | 161 | 27563 |
Dean F. Sittig | 71 | 381 | 17004 |
Thomas J. Schmugge | 63 | 188 | 13066 |
David C. Classen | 58 | 164 | 18303 |
James D. Kubicki | 58 | 216 | 10151 |
Damian J. Christian | 52 | 216 | 13461 |
Steven N. Shore | 46 | 234 | 6982 |
Chris Shrader | 45 | 140 | 10678 |
Rupak Biswas | 41 | 173 | 9962 |
M. P. Anantram | 40 | 174 | 6193 |
Theodore R. Gull | 39 | 125 | 6792 |
V. N. Venkatakrishnan | 38 | 95 | 5355 |
James P. Meador | 37 | 84 | 4630 |
Joel Wm. Parker | 36 | 176 | 4627 |