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

19-22 April 1994

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  • Bootstrap sampling applied to image analysis

    Publication Year: 1994, Page(s):VI/81 - VI/84 vol.6
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (359 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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  • Location of a dragline bucket in space using machine vision techniques

    Publication Year: 1994, Page(s):VI/161 - VI/164 vol.6
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    Because a dragline bucket's rigging is flexible, its position cannot be inferred from knowledge of rope length and boom position only. Moreover, active devices cannot be placed on the bucket itself to sense position because of the risk of damage. This paper describes a new machine vision system which is being developed to sense bucket position remotely. It is based on a single camera observing the... 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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  • 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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  • 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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  • Multidimensional wave-digital principles: from filtering to numerical integration

    Publication Year: 1994, Page(s):VI/173 - VI/181 vol.6
    Cited by:  Papers (19)
    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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  • 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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  • A new WDF three-port adaptor suitable for floating-point arithmetic and/or DSP implementations

    Publication Year: 1994, Page(s):VI/17 - VI/20 vol.6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    A new decomposed version of three-port adaptors for wave digital filters (WDFs) is proposed, which is especially suitable for floating-point arithmetic and for implementation on digital signal processors (DSPs). By using the proposed three-port adaptor, the concept of modified wave digital filters (MWDFs) is appropriately extended to WDFs involving any n-port adaptors (n is integer). The resulting... 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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  • A short history of the bootstrap

    Publication Year: 1994, Page(s):VI/65 - VI/68 vol.6
    Cited by:  Papers (1)
    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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  • High frequency atmospheric noise mitigation

    Publication Year: 1994, Page(s):VI/101 - VI/104 vol.6
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    The performance of high frequency (HF) radio communication and radar systems can be limited by noise generated by sources external to the receiving antenna. Below 10 MHz, atmospheric noise generated by worldwide thunderstorm activity tends to be the dominant natural source. We present an empirical analysis of atmospheric noise cancellation achieved by applying an adaptive sidelobe canceller to wid... View full abstract»

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  • On model identification for distortion correction of OTH radar signals

    Publication Year: 1994, Page(s):VI/129 - VI/132 vol.6
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    When HF skywave radars are employed for missions where high Doppler resolution is required, such as ship detection or remote sensing of the sea surface, nonstationarity of the ionospheric propagation channel within the coherent integration period often occurs to the extent that the Doppler spectrum is corrupted and the mission is unsuccessful. To overcome this problem, various signal processing te... View full abstract»

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  • An update on the CMU virtual laboratory

    Publication Year: 1994, Page(s):VI/53 - VI/56 vol.6
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (380 KB)

    The ECE department at CMU has implemented a new integrated curriculum which emphasizes learning in the context of applications. Development of a new laboratory paradigm has been critical to maximize conceptual learning while minimizing student busy work and faculty laboratory maintenance. The resulting virtual laboratory paradigm and redesign of the fundamental signals and systems course was the s... View full abstract»

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  • The design and development of an undergraduate signal processing laboratory

    Publication Year: 1994, Page(s):VI/41 - VI/44 vol.6
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    The School of Electrical and Electronic Systems Engineering of Queensland University of Technology (like many other universities around the world) has recognised the importance of complementing the teaching of signal processing with computer based experiments. A laboratory has been developed to provide a “hands-on” approach to the teaching of signal processing techniques. The motivatio... 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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  • An overview of multiple-window and quadratic-inverse spectrum estimation methods

    Publication Year: 1994, Page(s):VI/185 - VI/194 vol.6
    Cited by:  Papers (12)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (728 KB)

    Presents examples, history, and a brief review of the theory of multiple-window and quadratic-inverse spectrum estimation methods for mixed harmonizable processes. In addition to the standard uses of making consistent non-parametric auto- and cross-spectrum estimates with jackknife confidence intervals and estimating periodic components in coloured noise, quadratic-inverse theory gives a time-freq... 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 (6)
    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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  • Statistical signal processing for application to over-the-horizon radar

    Publication Year: 1994, Page(s):VI/113 - VI/116 vol.6
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    A review of recent developments in statistical signal processing for application to over-the-horizon radar (OTHR) is presented. Three different signal processing issues are considered. The first two issues relate to the radar interference characterisation, namely a Gaussianity test and a K-distribution test. The third issue relates to target detection in clutter based on rank tests. All techniques... View full abstract»

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  • Feature representations for monitoring of tool wear

    Publication Year: 1994, Page(s):VI/137 - VI/140 vol.6
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    We address the general problem of reliable, real-time detection of faults in metal-removal processes in manufacturing. As has long been recognized by skilled machine operators, mechanical and acoustic vibrations can be reliable sources of cues for such monitoring. However, conventional dull-tool monitoring systems, which are generally based on stationary signal processing methods, are inadequate f... 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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  • 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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  • Stability verification of multidimensional Kirchoff circuits by suitable energy functions

    Publication Year: 1994, Page(s):VI/13 - VI/16 vol.6
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    Multidimensional (MD) Kirchoff circuits (MDKC) are introduced in the theory of MD wave digital filters (MDWDF) in order to develop the so-called reference networks. Since MDWDF principles have also been used for numerical integration of partial differential equations (PDE) having physical relevance, MDKCs have received new significance because they can be used as an equivalent alternative represen... View full abstract»

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  • Discrete modelling of plasma equations with ion motion using technique of wave digital filters

    Publication Year: 1994, Page(s):VI/21 - VI/24 vol.6
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (200 KB)

    This paper shows how to solve a system of plasma equations consisting of Euler's and Maxwell's equation systems by using technique of wave digital filters. Since, in plasmas, the electromagnetic effect superposed in addition to the effect of thermal motion in the fluid, both Kirchhoff circuits derived from the equation systems have to be connected each other, which are transformed into well-known ... View full abstract»

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  • Signal processing education in the French system

    Publication Year: 1994, Page(s):VI/61 - VI/63 vol.6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    This paper investigates the French system of signal processing education. At first a general description of the French system of electrical engineering education is presented. Then the particular case of signal processing studies is described by using an example of one of the French universities 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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