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  • Comparative Studies. Non-European Languages/Literatures  (4)
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  • Comparative Studies. Non-European Languages/Literatures  (4)
RVK
  • 1
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2022
    In:  The Journal of the Acoustical Society of America Vol. 152, No. 1 ( 2022-07-01), p. 445-455
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 152, No. 1 ( 2022-07-01), p. 445-455
    Abstract: Detecting the presence or absence of a known signal is an important aspect of underwater acoustic (UWA) communications as it is a vital first step to process the received data. The influence of impulsive noise and multipath propagation on detection are both considered in this paper. Many robust detectors have been designed to cope with impulsive noise, but they tend to ignore the impact of multipath propagation, which may decrease the detection probability. To emphasize the role of multipath channel, we propose two-stage detection methods. In the first stage, the channel is estimated based on robust orthogonal matching pursuit, while in the second stage, detectors that use the channel estimation from the first stage, namely augmented log-likelihood ratio detector and augmented pseudo-correlation detector, are developed. The former detector is parametric and the latter one is non-parametric. The improved performance is demonstrated in simulated multipath channel and actual UWA channel with both simulated noise and recorded snapping shrimp noise, indicating that the proposed detectors are resistant to impulsive noise. It is also shown that the use of multipath information helps to improve the detection performance.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2022
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
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  • 2
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2016
    In:  The Journal of the Acoustical Society of America Vol. 140, No. 3 ( 2016-09-01), p. EL242-EL246
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 140, No. 3 ( 2016-09-01), p. EL242-EL246
    Abstract: Typhoon induced sediment warming has been proven important to coastal sound-field change in this study. It was observed that the temperature of the bottom waters off the coast of Qingdao increased by 5 °C after the passage of typhoon Damrey in 2012. Sediment warming due to bottom-water temperature increase was calculated and the change in sediment sound speed was estimated. Transmission loss (TL) was simulated both with and without consideration of the change in sediment sound speed induced by temperature variation and results showed TL change could be & gt;10 dB within a distance of 16 km.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2016
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
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  • 3
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2018
    In:  The Journal of the Acoustical Society of America Vol. 144, No. 6 ( 2018-12-01), p. EL522-EL527
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 144, No. 6 ( 2018-12-01), p. EL522-EL527
    Abstract: Underwater operational turbine noise emitted by China's first offshore wind farm in the East China Sea Bridge of Shanghai was measured and analyzed in this study. Two sensors were used in the measurement: a hydrophone recording the underwater sound and an accelerometer placed in the turbine tower detecting the tower vibrations. Measurements were performed at two different types of wind turbines: a Sinovel 3 MW SL3000 turbine and a Shanghai Electric 3.6 MW W3600 turbine. The two turbines show similar tower vibration characteristics, characterized by a number of tonal components, mainly in the low-frequency domain (30–500 Hz). The peak vibration frequencies changed with the wind speed until the turbine approached its nominal power rating. Spectral analysis of the underwater acoustic data showed that the amplitude spectra had a strong correlation with the spectra of the turbine vibration intensity level, indicating that the measured underwater noise was generated by the tower mechanical vibration.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2018
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
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  • 4
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2012
    In:  The Journal of the Acoustical Society of America Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3279-3279
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3279-3279
    Abstract: In this paper, the wave reflection at the interface between sea water and the half-space elastic bottom is considered and the sensitivity of reflection coefficient to the geoacoustic parameters, such as bottom density, P-wave velocity and its attenuation, S-wave velocity and its attenuation, has also been analyzed. In order to establish a geoacoustic inversion method with the ocean bottom reflection coefficient, a simulated experiment is carried out in the laboratory tank, where a PVC plate is used as the elastic bottom. In the experiment, a high-frequency underwater sound wave is transmitted by a source at fixed position and received using a hydrophone at different position with equal interval. By processing the measurement reflected signals at different receiving positions, the reflection coefficient for different incident angles can be obtained, with which the simulated bottom parameters have been inversed. An inversion method based on the sound transmission loss in water is also accomplished. These two inversion results are compared with the measurement result obtained according to the time delay for received multipath signals which reflect/refract at the liquid/elastic or solid/liquid interface of the PVC plate and the feasibility and reliability of the inversion from reflection data are discussed at last.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2012
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
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