Feature extraction for speech and music discrimination

Driven by the demand of information retrieval, video editing and human-computer interface, in this paper we propose a novel spectral feature for music and speech discrimination. This scheme attempts to simulate a biological model using the averaged cepstrum, where human perception tends to pick up the areas of large cepstral changes. The cepstrum data that is away from the mean value will be exponentially reduced in magnitude. We conduct experiments of music/speech discrimination by comparing the performance of the proposed feature with that of previously proposed features in classification. The dynamic time warping based classification verifies that the proposed feature has the best quality of music/speech classification in the test database

Exact form factors for the Josephson tunneling current and relative particle number fluctuations in a model of two coupled Bose-Einstein condensates

Form factors are derived for a model describing the coherent Josephson tunneling between two coupled Bose-Einstein condensates. This is achieved by studying the exact solution of the model in the framework of the algebraic Bethe ansatz. In this approach the form factors are expressed through determinant representations which are functions of the roots of the Bethe ansatz equations.Comment: 11 pages, latex, no figures, final version to appear in Lett. Math. Phy

Dynamics of a hole in the large--U Hubbard model: a Feynman diagram approach

We study the dynamics of a single hole in an otherwise half--filled two--dimensional Hubbard model by introducing a nonlocal Bogolyubov transformation in the antiferromagnetic state. This allows us to rewrite the Hamiltonian in a form that makes a separation between high--energy processes (involving double--occupancy) and low--energy physics possible. A diagrammatic scheme is developped that allows for a systematic study of the different processes delocalizing a carrier in the antiferromagnetic state. In particular, the so--called Trugman process, important if transverse spin fluctuations are neglected, is studied and is shown to be dominated by the leading vertex corrections. We analyze the dynamics of a single hole both in the Ising limit and with spin fluctuations. The results are compared with previous theories as well as with recent exact small--cluster calculations, and we find good agreement. The formalism establishes a link between weak and strong coupling methodologies.Comment: Latex 34pages, Orsay Preprint, submitted to Phys. Rev.

Synchronization of Chaotic Maps by Symmetric Common Noise

Synchronization of identical chaotic systems subjected to common noise has been the subject of recent research. Studies on several chaotic systems have shown that, the synchronization is actually induced by the non-zero mean of the noise, and symmetric noise with zero-mean cannot lead to synchronization. Here it is presented that synchronization can be achieved by {\sl zero-mean} noise in some chaotic maps with large convergence regions.Comment: 5 pages, 4 figure