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IEEE Journal of Oceanic Engineering

Issue 1 • Date Jan 1993

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Displaying Results 1 - 10 of 10
  • Three necessary conditions for the validity of the Fresnel phase approximation for the near-field beam pattern of an aperture

    Publication Year: 1993, Page(s):73 - 75
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    A simple, straightforward derivation of three necessary conditions that define the region of validity for the near-field directivity function (beam pattern) of an aperture (array) is presented. The derivation of all three criteria is based on determining what conditions must be satisfied in order to obtain a valid Fresnel approximation of the time-independent free-space Green's function. Compariso... View full abstract»

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  • Comments on `The real time implementation of propagator bearing estimation algorithm by the use of a neural network' by L. Fa-Long et al

    Publication Year: 1993
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (32 KB)

    In the above-titled paper (ibid., vol.17, p.320-5, Oct. 1992) the authors employ a propagator which they refer to as `the Marcos propagator' and credit S. Marcos and B. Benidir (1990) with its introduction. It is pointed out that this same operator was mentioned for the first time in French by Jacques Munier (1987). In that paper, Munier states that S. Spitz defined the same operator in an unpubli... View full abstract»

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  • A microstructure flux profiler control system design

    Publication Year: 1993, Page(s):42 - 54
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (904 KB)

    A microstructure flux profiler (MFP) which uses variation of its buoyancy to maintain the speed required for data logging is detailed. The variation of buoyancy to control speed is uncommon among profilers, and the autonomous operation of this device allows a much greater degree of flexibility in the data collection. The complete development of the control system, from modeling through simulation ... View full abstract»

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  • An intelligent control system for remotely operated vehicles

    Publication Year: 1993, Page(s):55 - 62
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB)

    The application of a neural network controller to remotely operated vehicles (ROVs) is described. Three learning algorithms for online implementation of a neural net controller are discussed with a critic equation. These control schemes do not require any information about the system dynamics except an estimate of the inertia terms. Selection of the number of layers in the neural network, the numb... View full abstract»

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  • Acoustic classification of abyssopelagic animals

    Publication Year: 1993, Page(s):63 - 72
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 KB)

    The unique environment of the abyssal plains allows many simplifying assumptions, facilitating the acoustic classification of an animal into one of two groups. The most important assumptions are based on low population densities and available target strength histograms and swim rate histograms. The likelihood ratio is formed from this information and accepted signal processing theory. The likeliho... View full abstract»

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  • Oceanographic variability in shallow-water acoustics and the dual role of the sea bottom

    Publication Year: 1993, Page(s):31 - 41
    Cited by:  Papers (4)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1080 KB)

    Acoustic propagation in shallow water is examined. Multipath propagation and extensive boundary interactions, which along with a host of other phenomena produce a highly variable and often unpredictable acoustic field, are discussed. The responsible mechanisms, and hence the acoustic effects, cover a wide range of temporal and spatial scales and are classified as either deterministic or random, al... View full abstract»

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  • The RRA algorithm: recursive ray acoustics for three-dimensional speeds of sound

    Publication Year: 1993, Page(s):25 - 30
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    A recursive ray acoustics (RRA) algorithm for three-dimensional speeds of sound is presented. The RRA algorithm is simple, fast, and accurate and uses arc length as the independent variable. In its present form, it can be used to compute the position, angles of propagation, travel time, and path length along a ray path. Preliminary results from computer simulation studies designed to test the algo... View full abstract»

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  • Spatial smoothing and minimum variance beamforming on data from large aperture vertical line arrays

    Publication Year: 1993, Page(s):15 - 24
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (908 KB)

    Various approaches to the beamforming of data from large aperture vertical line arrays are investigated. Attention is focused on the conventional beamforming problem where the angular power spectrum is estimated, in this case by the adaptive minimum variance processor. The data to be processed are 200 Hz CW transmissions collected at sea by a 900 m vertical line array with 120 equally spaced senso... View full abstract»

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  • Equivalent linear array approach to array pattern synthesis

    Publication Year: 1993, Page(s):6 - 14
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (652 KB)

    An effective method for array radiation pattern synthesis that allows formulation of the synthesis of a desired pattern as an optimization problem is presented. The solution proposed involves matrix operations based on the equivalent computation. The advantage of this approach is that it does not involve any numerical optimization routines-only ordinary matrix operations are required. Illustration... View full abstract»

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  • Fast matched field processing

    Publication Year: 1993, Page(s):1 - 5
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    It is shown how the computational burden of source localization by matched field processing (MFP) can be significantly reduced (20 to 30 times) by expressing the correlation in terms of a discrete Fourier transform and using the fast Fourier transform (FFT) algorithm. The price paid to achieve increased speed is in the form of quantization phase errors. It is shown through analysis and computer si... View full abstract»

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Aims & Scope

The IEEE Journal of Oceanic Engineering (ISSN 0364-9059) is the online-only quarterly publication of the IEEE Oceanic Engineering Society (IEEE OES). The scope of the Journal is the field of interest of the IEEE OES, which encompasses all aspects of science, engineering, and technology that address research, development, and operations pertaining to all bodies of water. This includes the creation of new capabilities and technologies from concept design through prototypes, testing, and operational systems to sense, explore, understand, develop, use, and responsibly manage natural resources.

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Meet Our Editors

Editor-in-Chief
N. Ross Chapman
School of Earth & Ocean Sciences
University of Victoria
3800 Finnerty Road
Victoria, BC V8P 5C2 Canada
chapman@uvic.ca