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Acoustics, Speech, and Signal Processing, 1994. ICASSP-94., 1994 IEEE International Conference on

Date 19-22 Apr 1994

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  • Exterior noise adaptive rejection for OTH radar implementations

    Publication Year: 1994, Page(s):VI/105 - VI/107 vol.6
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    A new class of nonstationary adaptive techniques is proposed to put up with clutter distortions originated from the current pattern readjustment, caused by the temporal perturbations of the jammer spatial covariance matrix. To introduce this approach we describe, by using the scalar-type vector-valued autoregressive model the inter-repetition sequence of the clutter-only antenna input snapshots ve... View full abstract»

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  • Multidimensional wave-digital principles: from filtering to numerical integration

    Publication Year: 1994, Page(s):VI/173 - VI/181 vol.6
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (868 KB)

    Wave-digital principles, originally developed for one-dimensional filtering purposes, have later been extended to multidimensional filtering applications and have been shown to be applicable also to numerical integration of physically relevant ordinary and partial (thus multidimensional) differential equations of linear and nonlinear type. They are based on physical concepts such as Kirchhoff circ... View full abstract»

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  • Processing of HF signals scattered by artificial ionospheric turbulence using fractal analysis

    Publication Year: 1994, Page(s):VI/169 - VI/171 vol.6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    An attempt has been made to apply fractal dimension analysis to HF radio signals scattered from natural and artificially stimulated ionospheric turbulence. Envelopes of the scattered signals in all cases showed a finite fractal dimension as estimated by the correlation integral technique. The signals scattered from artificial turbulence are characterized by a higher correlation dimension, while th... View full abstract»

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  • The processing of HF skywave radar signals

    Publication Year: 1994, Page(s):VI/165 - VI/168 vol.6
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    This paper presents an overview of a significant and computationally demanding application of signal processing, viz. over-the-horizon radar (OTHR). The Jindalee Operational Radar Network is an integrated network of OTHRs which depend heavily for their performance, in both air and surface mode, on signal processing. It outlines the characteristics of OTHR data that need to be recognised in the des... View full abstract»

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  • The Signal Processing Information Base project: the present and the future

    Publication Year: 1994, Page(s):VI/37 - VI/40 vol.6
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    The Signal Processing Information Base (SPIB) represents an attempt by the Signal Processing Society to make generally available information-data, papers, software, and bibliographies-necessary for state-of-the-art research and development. Access to the repository relies on the Internet, which makes SPIB available to students, researchers, and developers around the world. The variety of informati... View full abstract»

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  • Engineering education for the 21st century

    Publication Year: 1994, Page(s):VI/33 - VI/36 vol.6
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    The engineering environment of the 21st century will require new engineers to handle ambiguity and chaos, to understand the design/process/manufacture path for a product, to balance independence and teamwork, and to combine the techno-scientific base with a societal context. This paper summarizes some of the specific activities and experiments currently underway at universities in the United State... View full abstract»

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  • Bootstrapping autoregressions with infinite order

    Publication Year: 1994, Page(s):VI/97 - VI100 vol.6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    We consider a stationary autoregressive process of infinite order and discuss bootstrap procedures for the autocovariance function and the spectral density. After fitting an autoregressive process of increasing order to the observed data and estimating the parameter of the process we obtain estimated residuals. Now we construct an autoregressive bootstrap process with innovations which are distrib... View full abstract»

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  • Multiple testing for seismic data using bootstrap

    Publication Year: 1994, Page(s):VI/89 - VI/92 vol.6
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    Investigates the estimation of both the number of waves and of the wave parameters for wavefields in a geophysical application. A parametric method for wave parameter estimation in connection with a multiple test procedure is presented. The distribution of the corresponding test statistic for wideband data is approximated by the central limit theorem and alternatively by a bootstrap procedure. Fin... View full abstract»

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  • Numerical investigation of the Euler equations by means of wave digital filters

    Publication Year: 1994, Page(s):VI/1 - VI/4 vol.6
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    A fluid dynamic system can be described by nonlinear partial differential equations (PDEs). Well suited for simulation purposes is a discrete passive dynamic system, which can be found using principles known from the theory of multidimensional (MD) wave digital filters (WDF). All major features of the original physical system (e.g. massive parallelism, local interdependencies, MD-passivity etc.) a... View full abstract»

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  • Bootstrap sampling applied to image analysis

    Publication Year: 1994, Page(s):VI/81 - VI/84 vol.6
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    We present the bootstrap sampling techniques applied to some pattern recognition algorithms. Two important procedures in image analysis are tested: a statistical segmentation based on expectation-maximisation (EM) family algorithms and two methods of invariant features extraction for gray level images. In the first case, the results we obtain show that the bootstrap sample selection method gives b... View full abstract»

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  • Adaptive wave digital fan filters

    Publication Year: 1994, Page(s):VI/25 - VI/28 vol.6
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    Adaptive two-dimensional (2-D) fan filters based on least mean square algorithm and 2-D wave digital filter structure are presented. The weight updating equations as well as the equations for computing the gradient components of signals in two-dimensional wave digital filter adaptors are derived and specifically applied to wave digital quadrant and narrowband fan filters. Computer simulations are ... View full abstract»

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  • Multiple bootstrap tests and their application

    Publication Year: 1994, Page(s):VI/69 - VI/72 vol.6
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    We review bootstrap methods for testing statistical hypotheses. We begin with single hypothesis testing and give an example of its use. We then consider multiple testing based on Holm's step-down procedure and discuss how the bootstrap can incorporate relevant correlation and distributional characteristics. These techniques are applied to tests for zeros of transfer functions of linear systems at ... View full abstract»

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  • Jackknifed multiple-window spectra and coherence applied to seismic data

    Publication Year: 1994, Page(s):VI/93 - VI/96 vol.6
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    Examines the variance of power spectra and magnitude squared coherences determined from local earthquake seismograms recorded synchronously on a small aperture seismic array. The multiple taper algorithm is used to calculate the spectra and coherences. Variances of these estimates are calculated with the jackknife technique, after transforming to a more normal distribution, and are compared with e... View full abstract»

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  • Gaussian mixture model classifiers for machine monitoring

    Publication Year: 1994, Page(s):VI/133 - VI/136 vol.6
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    We describe a statistical pattern-recognition approach to machine monitoring. The approach comprises a classification scheme using Gaussian mixture models (GMMs) that classifies features based on a time-frequency representation using the wavelet transform. The GMM trained with the EM algorithm has comparable flexibility with the multilayered perceptron in modeling nonstationary, multimodal machine... View full abstract»

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  • Wave digital filters for the migration of seismic data

    Publication Year: 1994, Page(s):VI/5 - VI/8 vol.6
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    A closed form design method for migration wave digital filters (MWDF) is presented. Migration filters are 2-D fan shaped filters with a prescribed nonlinear phase in the passband. An analytical solution is presented which solves simultaneously the approximation problems for attenuation and phase. The attenuation is approximated in a maximally flat sense in pass- and stopband. The phase of the idea... View full abstract»

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  • Computing and signal processing: an experimental multidisciplinary course

    Publication Year: 1994, Page(s):VI/45 - VI/48 vol.6
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    In the Fall of 1993 at Berkeley we offered an experimental graduate course that focused on languages for modeling and design of signal processing systems. A major motivation for the course is our Ptolemy project, in which we are experimenting with models of computation and design methodology for signal processing systems. The applicable theory of computation primarily concerns stream datatypes and... View full abstract»

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  • A statistical model for the simulation of time-varying multipath mobile radio propagation channel

    Publication Year: 1994, Page(s):VI/149 - VI/152 vol.6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (260 KB)

    We propose a new model for the mobile radio channel which takes into account the channel non-stationarity. It is a statistical model whose parameters are derived from real impulse responses. It is based on modelling the variations of an existing stationary model when moving through small areas within which stationarity can be assumed. The stationary model used was developed in earlier work and con... View full abstract»

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  • A short history of the bootstrap

    Publication Year: 1994, Page(s):VI/65 - VI/68 vol.6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 KB)

    A very brief account is given of the history of bootstrap methods in statistics, including early contributions made by Mahalanobis, Quenouille, Tukey, Barnard and Hartigan as well as Efron. The definition of bootstrap methods is addressed View full abstract»

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  • Noise behaviour in the modified Fourier transform for interferometric data inversion

    Publication Year: 1994, Page(s):VI/157 - VI/160 vol.6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    Proposes a modified Fourier transform for the inversion of the visibility function acquired by an unidimensional interferometer observing the surface of the Earth from a low orbit. The inversion of the visibility function by the mean of the usual Fourier transform provides a profile of geometrically distorted brightness temperatures. A modified Fourier transform which takes into account the geomet... View full abstract»

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  • A bootstrap approach to estimating fractal dimensions

    Publication Year: 1994, Page(s):VI/85 - VI/88 vol.6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    This paper outlines a bootstrap approach to estimating the “correlation dimension” of a fractal measure, from a set of observations on that measure. An important example is estimating the dimension of the attractor of a chaotic system from a set of observations on that system. The method reduces the effects of dependence among the observations, is stable to minor variations in the proc... View full abstract»

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  • DSP and communication engineering education with graphical block diagram simulation tools

    Publication Year: 1994, Page(s):VI/57 - VI/60 vol.6
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    Graphical block diagram simulation tools with highly interactive plotting and visualization capabilities can accelerate and greatly improve DSP and communications education. In this paper, we present several projects given in graduate and senior level undergraduate courses in DSP and communications which use the graphical simulation tool Capsim, and emphasize the importance of true multi-rate sign... View full abstract»

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  • Fuzzy logic: issues, contentions and perspectives

    Publication Year: 1994
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (84 KB)

    There has been a rapid growth in the number and variety of applications of fuzzy logic. The successes of fuzzy logic have also generated a skeptical reaction. Most of the criticisms directed at fuzzy logic are rooted in a misunderstanding of what it is and/or a lack of familiarity with it. In many cases, what is not recognized is that the term fuzzy logic (FL) is actually used in two different sen... View full abstract»

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  • Signal processing of sky wave OTH-B radar

    Publication Year: 1994, Page(s):VI/117 - VI/120 vol.6
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    The design technique of signal processing of sky wave OTH-B radar is presented as well as 3D treatments in space, time and frequency domains and their performances. The technical insurance of a bistatic synchronization system and the characteristic of signal processing when detecting ship targets are reported briefly. The performances of a subarray are tested through several groups of experimental... View full abstract»

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  • Shape estimation and self-noise analysis for towed arrays

    Publication Year: 1994, Page(s):VI/153 - VI/155 vol.6
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    Towed line arrays of hydrophones are used in the underwater environment to detect weak signals, to resolve closely-spaced contacts and to estimate the bearing and other properties of acoustic sources. The detection performance of a towed array is limited by its self-noise. Towed array data are processed using an adaptive spatial filtering technique implemented in the frequency domain. The resultin... View full abstract»

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  • Bootstrapping coherency function

    Publication Year: 1994, Page(s):VI/77 - VI/79 vol.6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    In estimating spectrum and coherency function smoothing techniques have been widely used. However, smoothing creates undesirable bias consequently. We suggest the bootstrap method for the estimation of the bias and propose a bias-corrected estimator. Confidence bands are also considered by using a bootstrap estimate of the standard deviation. Simulation study are carried out for two cases View full abstract»

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