71,142 research outputs found
System and method for character recognition
A character recognition system is disclosed in which each character in a retina, defining a scanning raster, is scanned with random lines uniformly distributed over the retina. For each type of character to be recognized the system stores a probability density function (PDF) of the random line intersection lengths and/or a PDF of the random line number of intersections. As an unknown character is scanned, the random line intersection lengths and/or the random line number of intersections are accumulated and based on a comparison with the prestored PDFs a classification of the unknown character is performed
Pattern recognition technique
Technique operates regardless of pattern rotation, translation or magnification and successfully detects out-of-register patterns. It improves accuracy and reduces cost of various optical character recognition devices and page readers and provides data input to computer
Real time analysis of voiced sounds
A power spectrum analysis of the harmonic content of a voiced sound signal is conducted in real time by phase-lock-loop tracking of the fundamental frequency, (f sub 0) of the signal and successive harmonics (h sub 1 through h sub n) of the fundamental frequency. The analysis also includes measuring the quadrature power and phase of each frequency tracked, differentiating the power measurements of the harmonics in adjacent pairs, and analyzing successive differentials to determine peak power points in the power spectrum for display or use in analysis of voiced sound, such as for voice recognition
System design impact of guidance and navigation analysis for a SEPS 1979 Encke flyby
Baseline guidance and navigation strategy for an ecliptic projection of the Encke flyby mission consider solar electric propulsion stage parameters in generating optimized and targeted trajectory control. Results show the Encke relative approach error to be dominated by ephemerical uncertainties, particularly the velocity components
Anomalous Viscosity of the Quark-Gluon Plasma
The shear viscosity of the quark-gluon plasma is predicted to be lower than
the collisional viscosity for weak coupling. The estimated ratio of the shear
viscosity to entropy density is rather close to the ratio calculated by N = 4
super Yang-Mills theory for strong coupling, which indicates that the
quark-gluon plasma might be strongly coupled. However, in presence of momentum
anisotropy, the Weibel instability can arise and drive the turbulent transport.
Shear viscosity can be lowered by enhanced collisionality due to turbulence,
but the decorrelation time and its relation to underlying dynamics and
color-magnetic fields have not been calculated self-consistently. In this
paper, we use resonance broadening theory for strong turbulence to calculate
the anomalous viscosity of the quark-gluon plasma for nonequilibrium. For
saturated Weibel instability, we estimate the scalings of the decorrelation
rate and viscosity and compare these with collisional transport. This
calculation yields an explicit connection between the underlying momentum space
anisotropy and the viscosity anomaly.Comment: 16 pages, 2 figure
Translation to Bundle Operators
We give explicit formulas for conformally invariant operators with leading
term an -th power of Laplacian on the product of spheres with the natural
pseudo-Riemannian product metric for all .Comment: This is a contribution to the Proceedings of the 2007 Midwest
Geometry Conference in honor of Thomas P. Branson, published in SIGMA
(Symmetry, Integrability and Geometry: Methods and Applications) at
http://www.emis.de/journals/SIGMA
Quantitative Description of by the Hubbard Model in Infinite Dimensions
We show that the analytic single-particle density of states and the optical
conductivity for the half-filled Hubbard model on the Bethe lattice in infinite
dimensions describe quantitatively the behavior of the gap and the kinetic
energy ratio of the correlated insulator . The form of the optical
conductivity shows rising and is quite similar to the
experimental data, and the density of states shows behavior near
the band edges.Comment: 9 pages, revtex, 4 figures upon reques
COBE's Constraints on the Global Monopole and Texture Theories of Cosmic Structure Formation
We report on a calculation of large scale anisotropy in the cosmic microwave
background radiation in the global monopole and texture models for cosmic
structure formation. We have evolved the six component linear gravitational
field along with the monopole or texture scalar fields numerically in an
expanding universe and performed the Sachs-Wolfe integrals directly on the
calculated gravitational fields. On scales , we find a Gaussian
distribution with an approximately scale invariant fluctuation spectrum. The
amplitude is a factor of 4-5 larger than the prediction of the
standard CDM model with the same Hubble constant and density fluctuation
normalization. The recently reported COBE-DMR results imply that global
monopole and texture models require high bias factors or a large Hubble
constant in contrast to standard CDM which requires very low and bias
values. For , we find that normalizing
to the COBE results implies (95\% c.l.). If we restrict
ourselves to the range of bias factors thought to be reasonable before the
announcement of the COBE results, 1.5 \lsim b_8 \lsim 2.5, then it is fair to
conclude that global monopoles and textures are consistent with the COBE
results and are a {\it better} fit than Standard CDM.Comment: 8 pages, 5 figures (not included, but available by mail),
CfPA-TH-92-2
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