197,417 research outputs found
Geological evaluation of radar imagery - San Andreas fault zone from Stevens Creek, Santa Clara County to Mussel Rock, San Mateo County, California
Geologic interpretation of side-looking radar imagery using aerial photographs of Californi
An exact transformation from geocentric to geodetic coordinates for nonzero altitudes
An exact method for the nonzero altitude transformation from geocentric to geodetic coordinates is derived. The method is mathematically general and should serve as a primary standard
A general solution to the hidden-line problem
The requirements for computer-generated perspective projections of three dimensional objects has escalated. A general solution was developed. The theoretical solution to this problem is presented. The method is very efficient as it minimizes the selection of points and comparison of line segments and hence avoids the devastation of square-law growth
Vector statistics of LANDSAT imagery
A digitized multispectral image, such as LANDSAT data, is composed of numerous four dimensional vectors, which quantitatively describe the ground scene from which the data are acquired. The statistics of unique vectors that occur in LANDSAT imagery are studied to determine if that information can provide some guidance on reducing image processing costs. A second purpose of this report is to investigate how the vector statistics are changed by various types of image processing techniques and determine if that information can be useful in choosing one processing approach over another
Multiple pass reimaging optical system
An optical imaging system for enabling nonabsorbed light imaged onto a photodetective surface to be collected and reimaged one or more times onto that surface in register with the original image. The system includes an objective lens, one or more imaging lenses, one or more retroreflectors and perhaps a prism for providing optical matching of the imaging lens focal planes to the photo detective surface
United States Nuclear Export Controls
This article will explore the U.S. nuclear export controls regime. It will initially discuss controls affecting the export of nuclear material, facilities, and specially designed components of nuclear facilities. This section will specifically consider export licensing procedures and requirements, agreements for nuclear cooperation, the specific export criteria for major nuclear cooperation, as well as the necessary policy determination. Then the Article will discuss the procedures and requirements for obtaining a license to export dual-use equipment, the authorization necessary for the export of nuclear technology and the subsequent arrangement process, which further aids in the implementation of U.S. non-proliferation policies
The Effect of Corotation on the Radial Gradient of Metallicity of Spiral Galaxies
The corotation radius in a spiral galaxy is the radius where the spiral
pattern speed has the same velocity of the rotation curve. By compiling results
from the literature for 20 spiral galaxies we verified a strong correlation
between the radius of the minima or inflections of the metallicity distribution
and the corotation radius.Comment: 3 pages, 1 figur
Spectral studies of signals present in the command and communications system up-link transmitter
Spectral studies of signals present in command and communications system uplink transmitter of Saturn 5 radio frequency tracking and ranging system
Gravitational and electroweak unification by replacing diffeomorphisms with larger group
The covariance group for general relativity, the diffeomorphisms, is replaced
by a group of coordinate transformations which contains the diffeomorphisms as
a proper subgroup. The larger group is defined by the assumption that all
observers will agree whether any given quantity is conserved. Alternatively,
and equivalently, it is defined by the assumption that all observers will agree
that the general relativistic wave equation describes the propagation of light.
Thus, the group replacement is analogous to the replacement of the Lorentz
group by the diffeomorphisms that led Einstein from special relativity to
general relativity, and is also consistent with the assumption of constant
light velocity that led him to special relativity. The enlarged covariance
group leads to a non-commutative geometry based not on a manifold, but on a
nonlocal space in which paths, rather than points, are the most primitive
invariant entities. This yields a theory which unifies the gravitational and
electroweak interactions. The theory contains no adjustable parameters, such as
those that are chosen arbitrarily in the standard model.Comment: 28 pages
On the elimination of infinitesimal Gribov ambiguities in non-Abelian gauge theories
An alternative method to account for the Gribov ambiguities in gauge theories
is presented. It is shown that, to eliminate Gribov ambiguities, at
infinitesimal level, it is required to break the BRST symmetry in a soft
manner. This can be done by introducing a suitable extra constraint that
eliminates the infinitesimal Gribov copies. It is shown that the present
approach is consistent with the well established known cases in the literature,
i.e., the Landau and maximal Abelian gauges. The method is valid for gauges
depending exclusively on the gauge field and is restricted to classical level.
However, occasionally, we deal with quantum aspects of the technique, which are
used to improve the results.Comment: 29 pp. No figures. Discussions added. Final version to appear in EPJ
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