39,592 research outputs found

    A Comparison of Different Machine Transliteration Models

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    Machine transliteration is a method for automatically converting words in one language into phonetically equivalent ones in another language. Machine transliteration plays an important role in natural language applications such as information retrieval and machine translation, especially for handling proper nouns and technical terms. Four machine transliteration models -- grapheme-based transliteration model, phoneme-based transliteration model, hybrid transliteration model, and correspondence-based transliteration model -- have been proposed by several researchers. To date, however, there has been little research on a framework in which multiple transliteration models can operate simultaneously. Furthermore, there has been no comparison of the four models within the same framework and using the same data. We addressed these problems by 1) modeling the four models within the same framework, 2) comparing them under the same conditions, and 3) developing a way to improve machine transliteration through this comparison. Our comparison showed that the hybrid and correspondence-based models were the most effective and that the four models can be used in a complementary manner to improve machine transliteration performance

    The Synthesis, Resolution and Configuration of Beta-hydroxyvaline

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    Synthesis, resolution, and configuration of alpha-hydroxyvalin

    Optical Resolution and Configuration of Trans-2,3-epoxybutyric Acid

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    Optical resolution of epoxy derivative of butyric acid with brucine and configuration determination by treatment with ammoni

    Role of high-spin hyperon resonances in the reaction of γpK+K+Ξ\gamma p \to K^+ K^+ \Xi^-

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    The recent data taken by the CLAS Collaboration at the Thomas Jefferson National Accelerator Facility for the reaction of γpK+K+Ξ\gamma p \to K^+ K^+ \Xi^- are reanalyzed within a relativistic meson-exchange model of hadronic interactions. The present model is an extension of the one developed in an earlier work by Nakayama, Oh, and Haberzettl [Phys. Rev. C 74, 035205 (2006)]. In particular, the role of the spin-5/2 and -7/2 hyperon resonances, which were not included in the previous model, is investigated in the present study. It is shown that the contribution of the Σ(2030)\Sigma(2030) hyperon having spin-7/2 and positive parity has a key role to bring the model predictions into a fair agreement with the measured data for the K+ΞK^+\Xi^- invariant mass distribution.Comment: 8 pages, 3 figures, REVTe

    Einstein Manifolds As Yang-Mills Instantons

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    It is well-known that Einstein gravity can be formulated as a gauge theory of Lorentz group where spin connections play a role of gauge fields and Riemann curvature tensors correspond to their field strengths. One can then pose an interesting question: What is the Einstein equations from the gauge theory point of view? Or equivalently, what is the gauge theory object corresponding to Einstein manifolds? We show that the Einstein equations in four dimensions are precisely self-duality equations in Yang-Mills gauge theory and so Einstein manifolds correspond to Yang-Mills instantons in SO(4) = SU(2)_L x SU(2)_R gauge theory. Specifically, we prove that any Einstein manifold with or without a cosmological constant always arises as the sum of SU(2)_L instantons and SU(2)_R anti-instantons. This result explains why an Einstein manifold must be stable because two kinds of instantons belong to different gauge groups, instantons in SU(2)_L and anti-instantons in SU(2)_R, and so they cannot decay into a vacuum. We further illuminate the stability of Einstein manifolds by showing that they carry nontrivial topological invariants.Comment: v4; 17 pages, published version in Mod. Phys. Lett.

    Higgs bosons of a supersymmetric E6E_6 model at the Large Hadron Collider

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    It is found that CP symmetry may be explicitly broken in the Higgs sector of a supersymmetric E6E_6 model with two extra neutral gauge bosons at the one-loop level. The phenomenology of the model, the Higgs sector in particular, is studied for a reasonable parameter space of the model, in the presence of explicit CP violation at the one-loop level. At least one of the neutral Higgs bosons of the model might be produced via the WWWW fusion process at the Large Hadron Collider.Comment: 23 pages, 5 figures, JHE

    Explicit CP violation in a MSSM with an extra U(1)U(1)'

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    We study that a minimal supersymmetric standard model with an extra U(1)U(1)' gauge symmetry may accommodate the explicit CP violation at the one-loop level through radiative corrections. This model is CP conserving at the tree level and cannot realize the spontaneous CP violation for a wide parameter space at the one-loop level. In explicit CP violation scenario, we calculate the Higgs boson masses and the magnitude of the scalar-pseudoscalar mixings in this model at the one-loop level by taking into account the contributions of top quarks, bottom quarks, exotic quarks, and their superpartners. In particular, we investigate how the exotic quarks and squarks would affect the scalar-pseudoscalar mixings. It is observed that the size of the mixing between the heaviest scalar and pseudoscalar Higgs bosons is changed up to 20 % by a complex phase originated from the exotic quark sector of this model.Comment: 19 pages, 3 figure

    On the sign of the pi-rho-omega coupling constant

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    It is shown that the relative sign between the NNωNN\omega and πρω\pi\rho\omega coupling constants can be determined most sensitively from ω\omega production processes in NNNN collisions. Recent data on these reactions clearly favor the sign of the πρω\pi\rho\omega coupling constant which is opposite to that inferred from studies of the photoproduction reaction in combination with the vector meson dominance assumption and used by many authors. Implication of this finding in the description of other reactions is discussed.Comment: 6 pages, 4 figures, REVTeX, to be published in Phys. Lett.
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