103,571 research outputs found

    A New Data Processing Inequality and Its Applications in Distributed Source and Channel Coding

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    In the distributed coding of correlated sources, the problem of characterizing the joint probability distribution of a pair of random variables satisfying an n-letter Markov chain arises. The exact solution of this problem is intractable. In this paper, we seek a single-letter necessary condition for this n-letter Markov chain. To this end, we propose a new data processing inequality on a new measure of correlation by means of spectrum analysis. Based on this new data processing inequality, we provide a single-letter necessary condition for the required joint probability distribution. We apply our results to two specific examples involving the distributed coding of correlated sources: multi-terminal rate-distortion region and multiple access channel with correlated sources, and propose new necessary conditions for these two problems.Comment: 45 pages, 3 figures, submitted to IEEE Trans. Information Theor

    Studies of hypersonic viscous flows over a blunt body at low Reynolds number

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    Viscous hypersonic shock layer over blunt bodies at low Reynolds numbe

    Recent trends in particle size analysis techniques

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    Recent advances and developments in the particle-sizing technologies are briefly reviewed in accordance with three operating principles including particle size and shape descriptions. Significant trends of the particle size analysing equipment recently developed show that compact electronic circuitry and rapid data processing systems were mainly adopted in the instrument design. Some newly developed techniques characterizing the particulate system were also introduced

    Enhanced Static Approximation to the Electron Self-Energy Operator for Efficient Calculation of Quasiparticle Energies

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    An enhanced static approximation for the electron self energy operator is proposed for efficient calculation of quasiparticle energies. Analysis of the static COHSEX approximation originally proposed by Hedin shows that most of the error derives from the short wavelength contributions of the assumed adiabatic accumulation of the Coulomb-hole. A wavevector dependent correction factor can be incorporated as the basis for a new static approximation. This factor can be approximated by a single scaling function, determined from the homogeneous electron gas model. The local field effect in real materials is captured by a simple ansatz based on symmetry consideration. As inherited from the COHSEX approximation, the new approximation presents a Hermitian self-energy operator and the summation over empty states is eliminated from the evaluation of the self energy operator. Tests were conducted comparing the new approximation to GW calculations for diverse materials ranging from crystals and nanotubes. The accuracy for the minimum gap is about 10% or better. Like in the COHSEX approximation, the occupied bandwidth is overestimated.Comment: Submitted to Physical Review

    Majorana Neutrino Masses and Neutrino Oscillations

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    We examine some patterns of Majorana neutrino mass matrix which is compatible with the phenomenological lepton flavor mixing matrix and non-observation of neutrinoless double beta decay. Imposing (Mν)ee=0(M_{\nu})_{ee}=0 for the Majorana neutrino mass matrix in the leading order, we obtain a relationship between the solar mixing angle and the neutrino masses m1m_1 and m2m_2. Additional possible texture zeros are assigned to the mass matrix so as for the nonvanishing θ13\theta_{13} to be predictable in terms of neutrino masses. We also show how three neutrino masses can be predicted from the solar mixing angle and the experimental results of Δmsol2\Delta m^2_{sol} and Δmatm2\Delta m^2_{atm} in this framework, and we discuss naturality of the forms of the mass matrix found in our work.Comment: 14 pages, RevTe
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