1,854 research outputs found

    The complex relation between production and scattering amplitudes

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    The unitarity relation, Im(A)=T* A, is derived for a three-body production amplitude, A, that consists of a complex linear combination of elements of the two-body scattering amplitude, T. We conclude that the unitarity relation does not impose a realness condition on the coefficients in the expansion of, A, in terms of, T.Comment: 4 pages plain LaTe

    Advances in All-Neural Speech Recognition

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    This paper advances the design of CTC-based all-neural (or end-to-end) speech recognizers. We propose a novel symbol inventory, and a novel iterated-CTC method in which a second system is used to transform a noisy initial output into a cleaner version. We present a number of stabilization and initialization methods we have found useful in training these networks. We evaluate our system on the commonly used NIST 2000 conversational telephony test set, and significantly exceed the previously published performance of similar systems, both with and without the use of an external language model and decoding technology

    Tetraquark spectroscopy

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    A complete classification of tetraquark states in terms of the spin-flavor, color and spatial degrees of freedom was constructed. The permutational symmetry properties of both the spin-flavor and orbital parts of the quark-quark and antiquark-antiquark subsystems are discussed. This complete classification is general and model-independent, and is useful both for model-builders and experimentalists. The total wave functions are also explicitly constructed in the hypothesis of ideal mixing; this basis for tetraquark states will enable the eigenvalue problem to be solved for a definite dynamical model. This is also valid for diquark-antidiquark models, for which the basis is a subset of the one we have constructed. An evaluation of the tetraquark spectrum is obtained from the Iachello mass formula for normal mesons, here generalized to tetraquark systems. This mass formula is a generalizazion of the Gell-Mann Okubo mass formula, whose coefficients have been upgraded by means of the latest PDG data. The ground state tetraquark nonet was identified with f0(600)f_{0}(600), κ(800)\kappa(800), f0(980)f_{0}(980), a0(980)a_{0}(980). The mass splittings predicted by this mass formula are compared to the KLOE, Fermilab E791 and BES experimental data. The diquark-antidiquark limit was also studied.Comment: Invited talk at 11th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2007), Julich, Germany, 10-14 Sep 2007. In the Proceedings of 11th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2007), Julich, Germany, 10-14 Sep 2007, eConf C070910, 163 (2007

    The Active Traveling Wave in the Cochlea

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    A sound stimulus entering the inner ear excites a deformation of the basilar membrane which travels along the cochlea towards the apex. It is well established that this wave-like disturbance is amplified by an active system. Recently, it has been proposed that the active system consists of a set of self-tuned critical oscillators which automatically operate at an oscillatory instability. Here, we show how the concepts of a traveling wave and of self-tuned critical oscillators can be combined to describe the nonlinear wave in the cochlea.Comment: 5 pages, 2 figure

    A Novel Scheme to Search for Fractional Charge Particles in Low Energy Accelerator Experiments

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    In the Standard Model of particle physics, the quarks and anti-quarks have fractional charge equal to ±1/3\pm1/3 or ±2/3\pm2/3 of the electron's charge. There has been a large number of experiments searching for fractional charge, isolatable, elementary particles using a variety of methods, including e+e−e^+e^- collisions using dE/dx ionization energy loss measurements, but no evidence has been found to confirm existence of free fractional charge particles, which leads to the quark confinement theory. In this paper, a proposal to search for this kind particles is presented, which is based on the conservation law of four-momentum. Thanks to the CLEOc and BESIII detectors' large coverage, good particle identification, precision measurements of tracks' momenta and their large recorded data samples, these features make the scheme feasible in practice. The advantage of the scheme is independent of any theoretical models and sensitive for a small fraction of the quarks transitioning to the unconfinement phase from the confinement phase.Comment: 9 page

    Production of f0(1710)f_0(1710), f0(1500)f_0(1500), and f0(1370)f_0(1370) in J/ψJ/\psi hadronic decays

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    A coherent study of the production of f0if_0^i (i=1i=1, 2, 3 corresponding to f0(1710)f_0(1710), f0(1500)f_0(1500), and f0(1370)f_0(1370)) in J/ψ→Vf0→VPPJ/\psi\to V f_0 \to V PP is reported based on a previously proposed glueball and QQˉQ\bar{Q} nonet mixing scheme, and a factorization for the decay of J/ψ→Vf0iJ/\psi\to V f_0^i, where VV denotes the isoscalar vector mesons ϕ\phi and ω\omega, and PP denotes pseudoscalar mesons. The results show that the J/ψJ/\psi decays are very sensitive to the structure of those scalar mesons, and suggest a glueball in the 1.5−1.71.5-1.7 GeV region, in line with Lattice QCD. The presence of significant glueball mixings in the scalar wavefunctions produces peculiar patterns in the branching ratios for J/ψ→Vf0i→VPPJ/\psi\to V f_0^i\to VPP, which are in good agreement with the recently published experimental data from the BES collaboration.Comment: Version accepted by PRD; Numerical results in Tab IV and VI changed due to correction of an error in quoting an experimental datum; Conclusion is not change

    The Microsoft 2016 Conversational Speech Recognition System

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    We describe Microsoft's conversational speech recognition system, in which we combine recent developments in neural-network-based acoustic and language modeling to advance the state of the art on the Switchboard recognition task. Inspired by machine learning ensemble techniques, the system uses a range of convolutional and recurrent neural networks. I-vector modeling and lattice-free MMI training provide significant gains for all acoustic model architectures. Language model rescoring with multiple forward and backward running RNNLMs, and word posterior-based system combination provide a 20% boost. The best single system uses a ResNet architecture acoustic model with RNNLM rescoring, and achieves a word error rate of 6.9% on the NIST 2000 Switchboard task. The combined system has an error rate of 6.2%, representing an improvement over previously reported results on this benchmark task

    MONITORING THE SOFTWARE ASSET: REPOSITORY EVALUATION OF SOFTWARE REUSE

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    Traditionally, software management has focused primarily upon cost control. Today, with the emerging capabilities of computer aided software engineering (CASE) and corresponding changes in the development process, the opportunity exists to view software development as an activity that creates reusable software assets, rather than just expenses, for the corporation. With this opportunity comes the need to monitor software at the corporate level, as well as at that of the individual software development project. Integrated CASE environments can support such monitoring. In this paper we propose the use of a new approach called repository evaluation, and illustrate it in an analysis of the evolving repository-based software assets of two large firms that have implemented integrated CASE development tools. The analysis shows that these tools have supported high levels of software reuse, but it also suggests that there remains considerable unexploited reuse potential. Our findings indicate that organizational changes will be required before the full potential of the new technology can be realized.Information Systems Working Papers Serie

    FACTORS AFFECTING CODE REUSE: lMPLICATIONS FOR A MODEL OF COMPUTER AIDED SOFTWARE ENGINEERING DEVELOPMENT PERFORMANCE

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    An examination of code reuse at a large financial institution yields insights into the process of code reuse. The software development environment -- based on an integrated CASE system -- was designed to support code reuse, but at the end of its first two years we find that programmers are not taking full advantage of the reuse opportunities which the CASE environment provides, The organization has provided technical support for code reuse, but has not made organizational adjustments, and the technical solution alone does not suffice. We also review an existing economic model of CASE development performance that incorporates code reuse, suggesting refinements that are based upon our observations. Finally, we draw some conclusions about steps that managers can take to promote code reuse.Information Systems Working Papers Serie
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