3,156 research outputs found

    Automatic Classification and Speaker Identification of African Elephant (\u3cem\u3eLoxodonta africana\u3c/em\u3e) Vocalizations

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    A hidden Markov model (HMM) system is presented for automatically classifying African elephant vocalizations. The development of the system is motivated by successful models from human speech analysis and recognition. Classification features include frequency-shifted Mel-frequency cepstral coefficients (MFCCs) and log energy, spectrally motivated features which are commonly used in human speech processing. Experiments, including vocalization type classification and speaker identification, are performed on vocalizations collected from captive elephants in a naturalistic environment. The system classified vocalizations with accuracies of 94.3% and 82.5% for type classification and speaker identification classification experiments, respectively. Classification accuracy, statistical significance tests on the model parameters, and qualitative analysis support the effectiveness and robustness of this approach for vocalization analysis in nonhuman species

    Towards the P-wave nucleon-pion scattering amplitude in the Δ(1232)\Delta (1232) channel

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    We use lattice QCD and the L\"uscher method to study elastic pion-nucleon scattering in the isospin I=3/2I = 3/2 channel, which couples to the Δ(1232)\Delta(1232) resonance. Our Nf=2+1N_f=2+1 flavor lattice setup features a pion mass of mπ≈250m_\pi \approx 250 MeV, such that the strong decay channel Δ→πN\Delta \rightarrow \pi N is close to the threshold. We present our method for constructing the required lattice correlation functions from single- and two-hadron interpolating fields and their projection to irreducible representations of the relevant symmetry group of the lattice. We show preliminary results for the energy spectra in selected moving frames and irreducible representations, and extract the scattering phase shifts. Using a Breit-Wigner fit, we also determine the resonance mass mΔm_\Delta and the gΔ−πNg_{\Delta-\pi N} coupling.Comment: 14 pages, 7 figures, Proceedings of the 36th Annual International Symposium on Lattice Field Theory (Lattice 2018), 22-28 July 2018, Michigan State University, East Lansing, Michigan US
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