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IEEE Transactions on Acoustics, Speech, and Signal Processing

Issue 4 • Date Apr 1990

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Displaying Results 1 - 18 of 18
  • New parallel implementations for DTW algorithms

    Publication Year: 1990, Page(s):705 - 711
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (460 KB)

    The parallel realization of a popular dynamic time warping (DTW) algorithm is discussed. Two alternative techniques are proposed, one based on a circular array and the other using a linear array of processing elements (PEs). The architecture of each PE is defined in both cases and computational phases are outlined. The number of PEs is not restricted to be fixed. With small modifications, both of ... View full abstract»

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  • Event detection in multisource imaging: application to fine arts painting analysis

    Publication Year: 1990, Page(s):695 - 704
    Cited by:  Papers (7)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1140 KB)

    The standard statistical tools proposed in the literature for revealing changes between frames in a temporal sequence of images are ill suited to the detection of significant differences or changes (events) between pictures of a given scene taken at different wavelengths or with different sensors. A method for modeling a pair of multisource images so as to reveal significant changes between the tw... View full abstract»

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  • Resolution enhancement by periodicity constraints

    Publication Year: 1990, Page(s):687 - 694
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (464 KB)

    A scheme for enhancing the resolution of covariance-based direction-of-arrival estimators which is applicable to equispaced linear arrays and uncorrelated sources is discussed. It is based on the exploitation of the periodic structure of the spatial covariance function existing in these cases. Simulation results that demonstrate the enhanced resolution obtained by applying the method in conjunctio... View full abstract»

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  • Identification of time-varying systems using combined parameter estimation and filtering

    Publication Year: 1990, Page(s):679 - 686
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    The problem of tracking time-varying parameters of a linear stochastic system is considered, and an identification method based on parameter estimation and filtering is described. The proposed algorithm combines the standard weighted least squares (WLS) identification with low-pass filtering of parameter estimates. It is shown that the parameter tracking properties of the combined estimation-filte... View full abstract»

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  • Minimum mean absolute error estimation over the class of generalized stack filters

    Publication Year: 1990, Page(s):663 - 678
    Cited by:  Papers (59)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1192 KB)

    A class of sliding window operators called generalized stack filters is developed. This class of filters, which includes all rank order filters, stack filters, and digital morphological filters, is the set of all filters possessing the threshold decomposition architecture and a consistency property called the stacking property. Conditions under which these filters possess the weak superposition pr... View full abstract»

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  • Solving the attenuation problem in emission computed tomography using homomorphic filters

    Publication Year: 1990, Page(s):714 - 717
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    An approach to the attenuation problem in positron emission computed tomography (PET) is discussed. The underlying idea of the method, in which a homomorphic system and an iterative convolution backprojection algorithm are employed, is described. The use of these two algorithms in the new algorithm is discussed. Results obtained with the algorithms are judged acceptable, with the reconstructed ima... View full abstract»

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  • An approach to solving linear constant coefficient difference and differential equations

    Publication Year: 1990, Page(s):654 - 662
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (444 KB)

    The underlying structure inherent in the classical method of undetermined coefficients, which is used to obtain particular solutions to linear constant coefficient (LCC) difference or differential equations, is investigated. A system of equations of the form B=M-1 A is obtained, where B and A are vectors whose elements are the coefficients o... View full abstract»

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  • On weight update saturation nonlinearities in LMS adaptation

    Publication Year: 1990, Page(s):623 - 630
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (468 KB)

    The effect of a saturation-type nonlinearity in the weight update equation in least mean square (LMS) adaptation is investigated for a white Gaussian data model. Nonlinear difference equations that include the effect of a 1-e-ax saturation-type nonlinearity on the update term driving the algorithm are derived for the weight first and second moments. A nonlinear difference equat... View full abstract»

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  • Prescribed sidelobes for the constant beamwidth array

    Publication Year: 1990, Page(s):727 - 730
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    A linear array having constant beamwidth over an octave range can be constructed from a special arrangement of element positions and filters which alter the effective aperture with frequency. However, sidelobe level control is complicated by the aperture of an anomalous lobe when the array is steered away from the broadside View full abstract»

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  • Context-dependent phonetic hidden Markov models for speaker-independent continuous speech recognition

    Publication Year: 1990, Page(s):599 - 609
    Cited by:  Papers (80)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1004 KB)

    Context-dependent phone models are applied to speaker-independent continuous speech recognition and shown to be effective in this domain. Several previously proposed context-dependent models are evaluated, and two new context-dependent phonetic units are introduced: function-word-dependent phone models, which focus on the most difficult subvocabulary; and generalized triphones, which combine simil... View full abstract»

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  • Tracking capabilities of the LMS adaptive filter in the presence of gain variations

    Publication Year: 1990, Page(s):712 - 714
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    The tracking capabilities of the least mean square (LMS) adaptive filter when it is used to identify a nonstationary channel suffering from gain variations are studied. An analytical solution for the steady-state lag error is obtained, and its validity is verified by means of simulations. Depending on the magnitude and bandwidth of the variations, the total steady-state error is found either to in... View full abstract»

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  • An information theoretic spectral density

    Publication Year: 1990, Page(s):717 - 721
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    An information theoretic spectrum which minimizes the Kullback-Leibler (1951) information number subject to the first p +1 autocovariance terms is proposed. The KL spectrum includes the maximum-entropy spectrum and the ARMA (autoregressive moving-average) spectrum as special cases. A method is proposed for modifying a spectral estimate, on the basis of the results for the KL spectrum, so ... View full abstract»

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  • The fast adaptive ROTOR's RLS algorithm

    Publication Year: 1990, Page(s):631 - 653
    Cited by:  Papers (79)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1472 KB)

    A fast algorithm for implementation of the QR-factorization-based recursive-least-squares (RLS) adaptive filter is discussed. This fast adaptive rotors (FAR) algorithm can be implemented with a pipelined array of processors called ROTORs and CISORs. The ROTORs compute 2×2 orthogonal (Givens) rotations, and the CISORs compute the cosines and sines of the angles used in the ROTORs. The algorit... View full abstract»

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  • The moments of matched and mismatched hidden Markov models

    Publication Year: 1990, Page(s):610 - 622
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1008 KB)

    An algorithm for computing the moments of matched and mismatched hidden Markov models (HMMs) from their defining parameters is presented. The algorithm is an extension of the usual forward-backward linear recursion. The algorithm computes the joint moments of the posterior likelihood functions (i.e. the scores) by a multilinear recursion involving the joint moments of the random variables associat... View full abstract»

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  • Sliding windows and lattice algorithms for computing QR factors in the least squares theory of linear prediction

    Publication Year: 1990, Page(s):721 - 725
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    The authors pose a sequence of linear prediction problems that differ a little from those previously posed. The solutions to these problems introduce a family of sliding window techniques into the least-squares theory of linear prediction. By using these techniques it is possible to perform QR factorization of the Toeplitz data matrices that arise in linear prediction. The matrix ... View full abstract»

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  • Huffman code-fed omnidirectional acoustical arrays

    Publication Year: 1990, Page(s):577 - 585
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (568 KB)

    The synthesis of linear and planar acoustical arrays of desired omnidirectional intensity patterns is considered. It is shown that an almost omnidirectional pattern results when a code with a sharp correlation function is used as the feeding sequence for the elements of the array. The properties of Huffman codes are described, with special attention to integer Huffman codes, and examples of linear... View full abstract»

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  • Time-frequency distributions for a wide-sense stationary random signal

    Publication Year: 1990, Page(s):725 - 727
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    It is shown that a wide class of time-frequency distributions gives the power spectrum for the case of a wide-sense stationary random signal. A simple criterion on the Cohen (1966) kernel for determining when a bilinear time-frequency distribution gives the power spectrum of the signal is derived View full abstract»

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  • Frequency line tracking using hidden Markov models

    Publication Year: 1990, Page(s):586 - 598
    Cited by:  Papers (88)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1292 KB)

    Frequency cells comprising a subset, or gate, of the spectral bins from fast Fourier transform (FFT) processing are identified with the states of the hidden Markov chain. An additional zero state is included to allow for the possibility of track initiation and termination. Analytic expressions for the basic parameters of the hidden Markov model (HMM) are obtained in terms of physically meaningful ... View full abstract»

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Aims & Scope

This Transactions ceased production in 1990. The current retitled publication is IEEE Transactions on Signal Processing.

Full Aims & Scope