69,833 research outputs found

    System and method for character recognition

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    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

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    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

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    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

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    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

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    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

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    We give explicit formulas for conformally invariant operators with leading term an mm-th power of Laplacian on the product of spheres with the natural pseudo-Riemannian product metric for all mm.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 V2O3V_2O_3 by the Hubbard Model in Infinite Dimensions

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    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 V2O3V_2O_3. The form of the optical conductivity shows ω3/2\omega^{3/2} rising and is quite similar to the experimental data, and the density of states shows ω1/2\omega^{1/2} 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

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    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 >7> 7^\circ, we find a Gaussian distribution with an approximately scale invariant fluctuation spectrum. The ΔT/T\Delta T/T 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 H0H_0 and bias values. For H0=70kmsecMpc1H_0 = 70 {\rm {km\over sec} Mpc^{-1}}, we find that normalizing to the COBE results implies b83.2±1.4b_8 \simeq 3.2\pm 1.4 (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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