83,862 research outputs found

    Homogenous Ensemble Phonotactic Language Recognition Based on SVM Supervector Reconstruction

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    Currently, acoustic spoken language recognition (SLR) and phonotactic SLR systems are widely used language recognition systems. To achieve better performance, researchers combine multiple subsystems with the results often much better than a single SLR system. Phonotactic SLR subsystems may vary in the acoustic features vectors or include multiple language-specific phone recognizers and different acoustic models. These methods achieve good performance but usually compute at high computational cost. In this paper, a new diversification for phonotactic language recognition systems is proposed using vector space models by support vector machine (SVM) supervector reconstruction (SSR). In this architecture, the subsystems share the same feature extraction, decoding, and N-gram counting preprocessing steps, but model in a different vector space by using the SSR algorithm without significant additional computation. We term this a homogeneous ensemble phonotactic language recognition (HEPLR) system. The system integrates three different SVM supervector reconstruction algorithms, including relative SVM supervector reconstruction, functional SVM supervector reconstruction, and perturbing SVM supervector reconstruction. All of the algorithms are incorporated using a linear discriminant analysis-maximum mutual information (LDA-MMI) backend for improving language recognition evaluation (LRE) accuracy. Evaluated on the National Institute of Standards and Technology (NIST) LRE 2009 task, the proposed HEPLR system achieves better performance than a baseline phone recognition-vector space modeling (PR-VSM) system with minimal extra computational cost. The performance of the HEPLR system yields 1.39%, 3.63%, and 14.79% equal error rate (EER), representing 6.06%, 10.15%, and 10.53% relative improvements over the baseline system, respectively, for the 30-, 10-, and 3-s test conditions

    B to tensor meson form factors in the perturbative QCD approach

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    We calculate the Bu,d,s→TB_{u,d,s}\to T form factors within the framework of the perturbative QCD approach, where TT denotes a light tensor meson with JP=2+J^P=2^+. Due to the similarities between the wave functions of a vector and a tensor meson, the factorization formulas of B→TB\to T form factors can be obtained from the B→VB\to V transition through a replacement rule. As a consequence, we find that these two sets of form factors have the same signs and correlated q2q^2-dependence behaviors. At q2=0q^2=0 point, the B→TB\to T form factors are smaller than the B→VB\to V ones, in accordance with the experimental data of radiative B decays. In addition, we use our results for the form factors to explore semilteptonic B→TlνˉlB\to Tl\bar \nu_l decays and the branching fractions can reach the order 10−410^{-4}.Comment: 13 pages, 3 figures, 6 tables, published versio

    On the Construction of Radio Environment Maps for Cognitive Radio Networks

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    The Radio Environment Map (REM) provides an effective approach to Dynamic Spectrum Access (DSA) in Cognitive Radio Networks (CRNs). Previous results on REM construction show that there exists a tradeoff between the number of measurements (sensors) and REM accuracy. In this paper, we analyze this tradeoff and determine that the REM error is a decreasing and convex function of the number of measurements (sensors). The concept of geographic entropy is introduced to quantify this relationship. And the influence of sensor deployment on REM accuracy is examined using information theory techniques. The results obtained in this paper are applicable not only for the REM, but also for wireless sensor network deployment.Comment: 6 pages, 7 figures, IEEE WCNC conferenc

    Existence and stability analysis of spiky solutions for the Gierer-Meinhardt system with large reaction rates

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    We study the Gierer-Meinhardt system in one dimension in the limit of large reaction rates. First we construct three types of solutions: (i) an interior spike; (ii) a boundary spike and (iii) two boundary spikes. Second we prove results on their stability. It is found that an interior spike is always unstable; a boundary spike is always stable. The two boundary spike configuration can be either stable or unstable, depending on the parameters. We fully classify the stability in this case. We characterise the destabilizing eigenfunctions in all cases. Numerical simulations are shown which are in full agreement with the analytical results

    Baryon states with hidden charm in the extended local hidden gauge approach

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    The s-wave interaction of DˉΛc,DˉΣc,DˉΛc,Dˉ∗Σc\bar{D} \Lambda_c, \bar{D} \Sigma_c, \bar{D} \Lambda_c, \bar{D}{}^* \Sigma_c and DˉΣc∗,Dˉ∗Σc∗\bar{D}\Sigma^*_c, \bar{D}{}^*\Sigma^*_c, is studied within a unitary coupled channels scheme with the extended local hidden gauge approach. In addition to the Weinberg-Tomozawa term, several additional diagrams via the pion-exchange are also taken into account as box potentials. Furthermore, in order to implement the full coupled channels calculation, some of the box potentials which mix the vector-baryon and pseudoscalar-baryon sectors are extended to construct the effective transition potentials. As a result, we have observed six possible states in several angular momenta. Four of them correspond to two pairs of admixture states, two of DˉΣc\bar{D}\Sigma_c - Dˉ∗Σc\bar{D}{}^*\Sigma_c with JP=1/2−J^P = 1/2^-, and two of DˉΣc∗\bar{D}\Sigma^*_c - Dˉ∗Σc∗\bar{D}{}^*\Sigma^*_c with JP=3/2−J^P = 3/2^-. Moreover, we find a Dˉ∗Σc\bar{D}{}^* \Sigma_c resonance which couples to the DˉΛc\bar{D}\Lambda_c channel and one spin degenerated bound state of Dˉ∗Σc∗\bar{D}{}^*\Sigma^*_c with JP=1/2−,5/2−J^P = 1/2^-, 5/2^-.Comment: 24 pages, 6 figure
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