87,610 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

    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

    Mathematical Formalism for Isothermal Linear Irreversibility

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    We prove the equivalence among symmetricity, time reversibility, and zero entropy production of the stationary solutions of linear stochastic differential equations. A sufficient and necessary reversibility condition expressed in terms of the coefficients of the equations is given. The existence of a linear stationary irreversible process is established. Concerning reversibility, we show that there is a contradistinction between any 1-dimensional stationary Gaussian process and stationary Gaussian process of dimension n>1n>1. A concrete criterion for differentiating stationarity and sweeping behavior is also obtained. The mathematical result is a natural generalization of Einstein's fluctuation-dissipation relation, and provides a rigorous basis for the isothermal irreversibility in a linear regime which is the basis for applying Onsager's theory to macromolecules in aqueous solution.Comment: 15 page

    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

    Combined Effect of QCD Resummation and QED Radiative Correction to W boson Observables at the Tevatron

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    A precise determination of the W boson mass at the Fermilab Tevatron requires a theoretical calculation in which the effects of the initial-state multiple soft-gluon emission and the final-state photonic correction are simultaneously included . Here, we present such a calculation and discuss its prediction on the transverse mass distribution of the W boson and the transverse momentum distribution of its decay charged lepton, which are the most relevant observables for measuring the W boson mass at hadron colliders.Comment: 10 pages, 3 Postscript figures, uses revtex4.st
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