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Signals, Systems and Computers, 1992. 1992 Conference Record of The Twenty-Sixth Asilomar Conference on

Date 26-28 Oct. 1992

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  • Conference Record of The Twenty-Sixth Asilomar Conference on Signals, Systems and Computers (Cat. No.92CH3245-8)

    Publication Year: 1992
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    Freely Available from IEEE
  • Exact expectation analysis of the sign-data LMS algorithm for i.i.d. input data

    Publication Year: 1992, Page(s):566 - 570 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    The author presents an automated method of deriving an exact description of the convergence behavior of a class of nonlinearity modified data adaptive algorithms for system identification modeling with independent, identically distributed (i.i.d.) samples as input data. Using the method, a set of linear equations that exactly describes a nonlinear data algorithm's stochastic behavior at each time ... View full abstract»

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  • Segmentation of grey scale sampled images with bimodal source models

    Publication Year: 1992, Page(s):456 - 460 vol.1
    Cited by:  Papers (1)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    A gray-level-sampled image of a bimodal source will have some deviations from a perfect bimodal distribution due to added source, partial volume effects, and slow variations in source intensity. If the high contrast source image is to be accurately estimated from the sampled image, the characteristics of the image acquisition system must be selected to preserve the required information. These char... View full abstract»

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  • An adaptive, soft-decision multiuser receiver for underwater acoustical channels

    Publication Year: 1992, Page(s):1137 - 1141 vol.2
    Cited by:  Papers (4)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    A technique for resolving the collision of inband and asynchronous packets, with the goal of demodulating both strong and weak signals within a fixed amount of time, is presented. The particular case of coherent, binary phase shift keying (BPSK) for each data packet is discussed. The transmitting waveforms are assumed to be known by the central receiver for all modems, but the amplitude, Doppler, ... View full abstract»

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  • Fixed versus correlation-adaptive LMS acoustic narrowband arrays for hearing enhancement

    Publication Year: 1992, Page(s):571 - 575 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    The authors compare the performance of two-element and four-element correlation-adaptive least-mean-square (LMS) narrowband arrays versus fixed array designs in the presence of spatially separated noise sources. These arrays are designed to fit on the human head in an unobtrusive manner. Head shadow (acoustic occlusion) modeling is included. The directionality of the fixed beamformers is shown to ... View full abstract»

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  • Blind equalization of fading channels

    Publication Year: 1992, Page(s):324 - 328 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    Two blind equalization schemes using an antenna array are proposed for multipath fading channels. The methods exploit second-order statistics and spatial diversity to provide fast convergence rate and better performance in low SNRs. A special orthogonalization technique is used in conjunction with the Viterbi algorithm to achieve optimal sequence detection without channel identification. The propo... View full abstract»

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  • Array manifold interpolation for diversely polarized arrays

    Publication Year: 1992, Page(s):214 - 218 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    The interpolation problem for diversely polarized antenna arrays is examined, and interpolation techniques that provide precise direction-of-arrival (DOA) and polarization estimates are proposed. Azimuth, elevation, and frequency interpolation are also considered. The performance of the method is tested on several arrays View full abstract»

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  • Scale and rotation invariant texture classification

    Publication Year: 1992, Page(s):461 - 465 vol.1
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    The problem of classifying scaled and rotated texture images is addressed using a number of different approaches. The first approach extracts invariant features from texture images; moment invariant features and log-polar filter features are employed. The second approach follows a mental transformation procedure similar to the process of scaled and rotated shape recognition carried out by human be... View full abstract»

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  • State-space characterization of Viterbi detector path metric differences

    Publication Year: 1992, Page(s):940 - 944 vol.2
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    Issues related to determining the state-space of survivor path metric differences in applications of the Viterbi algorithm are explored. In particular, the problem of characterizing the entire space of path metric differences, achievable from a given initial state, and calculating the probability density for the differences as a function of the distribution of the (noisy) channel output samples is... View full abstract»

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  • A methodology for comparing fault tolerant computers

    Publication Year: 1992, Page(s):999 - 1003 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    A general methodology for comparing fault tolerant computers using a hierarchical taxonomy of pertinent issues is described. The uppermost level taxonomy consists of reliability, specialized fault detection, performance, flexibility, and communication issues. Each class is further decomposed into more specific topics. The methodology consists of studying each issue in turn to determine which candi... View full abstract»

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  • Wavelets and image compression

    Publication Year: 1992, Page(s):701 - 704 vol.2
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    The notion of wavelet transforms and their application to image compression are discussed. It is noted that, at higher compression ratios, the performance of the Haar transform based algorithm is visually superior to that of the JPEG DCT-based one. The edges are as clearly defined as for the DCT-based algorithm and the blockiness is significantly less severe than for the latter method. The impleme... View full abstract»

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  • Maximum likelihood detection of co-channel communication signals via exploitation of spatial diversity

    Publication Year: 1992, Page(s):1142 - 1146 vol.2
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    A maximum-likelihood method is used to jointly detect multiple cochannel communication signals. The joint detection idea is explained by considering the simple case in which all the signals are synchronized. Extensions to more complicated cases for asynchronized and convolutionally coded signals are discussed. Computer simulations have been conducted to compare the performance of the proposed dete... View full abstract»

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  • High resolution spectrum estimation

    Publication Year: 1992, Page(s):498 - 501 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    A new approach to improve the frequency resolution of parametric power spectrum estimation for signals with rational power spectra is proposed. Specifically, the effect of errors in the calculated autocorrelation values is reduced by using a double autocorrelation procedure. The numerical solution of the resulting Yule-Walker equations is carried out by the forward and backward linear predictor me... View full abstract»

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  • Outage probability in digital cellular radio networks

    Publication Year: 1992, Page(s):88 - 92 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    The block outage probability that the voice segment is lost in digital cellular radio networks using TDMA because of a temporary fade during part of its reception is studied. The combined effects of multipath fading and shadowing of the wanted and interfering signals are considered. To this end, the model for RF outage probabilities, as appropriate for analog transmission, is extended to include t... View full abstract»

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  • Adaptive RRQR-based factorization: Improving the algorithm tracking capabilities

    Publication Year: 1992, Page(s):576 - 580 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    An improvement to a rank-revealing QR (RRQR) updating procedure proposed earlier is presented. The method takes advantage of the simplicity of the QR updating scheme, the rank-revealing property proposed by T.F. Chan (1987), and the Hermitian property of correlation matrices. Simulations show that the `refined' RRQR-based updating scheme approximates signal (and noise) subspaces closely and is rob... View full abstract»

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  • Acoustic vector sensor array processing

    Publication Year: 1992, Page(s):192 - 198 vol.1
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (508 KB)

    An approach is proposed for localization of acoustic sources using an array of sensors for which the measurement of each sensor is a vector consisting of the acoustic pressure and acoustic particle velocity. A compact expression is derived for the Cramer-Rao bound (CRB) on the estimation errors of the source direction-of-arrival (DOA) parameters in the multi-source multi-vector sensor model. An ex... View full abstract»

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  • Blind deconvolution based criteria for parameter estimation with noisy data

    Publication Year: 1992, Page(s):329 - 333 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    The author considers the problem of estimating the parameters of a stable, scalar ARMA(p,q) signal model (causal or noncausal, minimum phase or mixed phase), driven by an independent and identically distributed nonGaussian sequence. The driving noise sequence is not observed. A class of criteria that involve explicit higher order whitening, where higher order cumulants of deconvo... View full abstract»

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  • Error bounds for MEG and EEG source localization

    Publication Year: 1992, Page(s):150 - 155 vol.1
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (520 KB)

    Localization error bounds are presented for both electroencephalograms (EEGs) and magnetoencephalograms (MEGs) as graphical error contours for a 37-sensor arrangement. Both one and two dipole cases were examined for all possible dipole orientations and locations within a head quadrant. The results show a strong dependence on absolute dipole location and orientation. The results also show that fusi... View full abstract»

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  • Matched field processing: source localization in waveguides

    Publication Year: 1992, Page(s):1122 - 1126 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    Matched field processing (MFP), a generalized beamforming method which uses the complexity of an acoustic file in the ocean to localize sources in range, depth, and azimuth and to estimate parameters of the waveguide itself, is discussed. MFP exploits the coherence of the modal/multipath structure of the signals by using the full-field Green's function for the signal propagation. It is especially ... View full abstract»

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  • The wave packet transform (WPT) as applied to signal processing

    Publication Year: 1992, Page(s):484 - 487 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    The wave packet transform (WPT) is introduced. It uses the Weyl operator and wave packet functions, i.e., functions that are similar to wavelets, in a linear form to compute coefficients in a two-dimensional space of time and frequency. The importance of the Weyl operator in the WPT and its use with different wave packets are discussed. It is shown that the energetic form of the WPT, the wavepacke... View full abstract»

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  • Cumulant-based blind optimum beamforming

    Publication Year: 1992, Page(s):209 - 213 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    The authors propose blind estimation of the source steering vector in the presence of multiple, directional, correlated or coherent Gaussian interferers via higher-order statistics. In any application, only sample statistics are available, so a robust beamforming approach that employs the steering vector estimate obtained by cumulant-based signal processing is suggested. A method that employs both... View full abstract»

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  • Computer vision and sensor fusion for detecting buried objects

    Publication Year: 1992, Page(s):466 - 471 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (452 KB)

    Given multiple images of the Earth's surface from dual-band infrared sensors, a system that fuses information from the sensors to reduce the effects of clutter and improve the ability to detect buried or surface target sites is presented. Supervised learning pattern classifiers (including neural networks) are used. Results of experiments to detect buried land mines from real data are given, and th... View full abstract»

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  • Multi-level decision feedback equalization with clock recovery

    Publication Year: 1992, Page(s):945 - 949 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    Analytical expressions are developed to describe the dynamic response of the phase detector in multilevel decision feedback equalization (MDFE). First, it is shown that high density recording channels using a 2/3(1,7) run-length code are bandlimited, so that the Nyquist sampling criterion is satisfied. Consequently, the phase-locked loop (PLL) can be analyzed using sin x/x interp... View full abstract»

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  • Digital filters with peak-constrained weighted least-squared errors

    Publication Year: 1992, Page(s):256 - 260 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    Digital filter design algorithms that extend peak-constrained weighted least-squared error optimization methods to cover a wide range of problems are presented. It is shown that the optimization problem can be solved in terms of the equivalent problem of minimizing a modified total weighted-square error function. Several different approaches to determining the modified weighting function using ite... View full abstract»

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  • Quadrature splitter considerations for digital cellular radio

    Publication Year: 1992, Page(s):606 - 611 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (436 KB)

    A quadrature splitter for converting a narrowband bandpass IF or RF signal into baseband inphase and quadrature phase signals is evaluated in a high IF cellular digital radio system with a total bandwidth of 25 MHz. The results show that the simple splitter causes spectrum residues due to the relatively small ratio of sampling frequency to total signal bandwidth. These spectrum residues result in ... View full abstract»

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