Searched for: subject%3A%22AS%255C%2B%255C-%255C%2BAcoustics%255C%2B%2526%255C%2BSonar%22
(301 - 320 of 342)
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Ho, J.-H. (author), Berkhoff, A.P. (author)This paper presents an investigation of the cavity and the panel resonance control in a double‐panel structure. The double‐panel structure, which consists of two panels with air in the gap, is widely adopted in many applications such as aerospace due to its light weight and effective transmission‐loss at high frequency. However, the resonance of...conference paper 2011
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Ainslie, M.A. (author), de Jong, C.A.F. (author)Early human interest in ambient noise in the sea, especially during and after the Second World War, resulted from its effect on limiting the performance of military search sonar [Urick 1983]. While that interest continues, it is now accompanied by non-military uses of underwater sound, such as navigation, fisheries, oceanography and seismic...conference paper 2011
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Tang, Z. (author), Remis, R. (author), Xu, T. (author), Leus, G. (author), Nordenvaad, M.L. (author)We consider an orthogonal frequency-division multiplexing (OFDM) transmission scheme over wideband underwater acoustic channels, where the propagation paths can experience distinct Doppler effects (manifested in signal scales) and time of arrivals (manifested in lags). We capture such an effect in this paper with a multi-scale multi-lag (MSML)...conference paper 2011
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Kastelein, R. (author), Gransier, R. (author), van Mierlo, R. (author), Hoek, L. (author), de Jong, C.A.F. (author)To set safety criteria for levels of sounds produced during pile driving for offshore wind parks, temporary hearing threshold shifts sTTSsd were studied in a harbor porpoise and two harbor seals. A psychoacoustic behavioral technique was used to quantify TTS and hearing recovery in the animals exposed to underwater sounds swhite noise in a 1/1...article 2011
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van der Eerden, F.J.M. (author), Lutgendorf, D. (author), de Roo, F. (author)Within the EU FP7 QUIESST project, QUIeting the Environment for a Sustainable Surface Transport, a test method is being developed for the reflectivity of noise barriers. The method needs to account for a complex shape of barriers and the use of various types of absorbing materials. The performance of a barrier is to be measured in the near field...conference paper 2011
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van Vossen, R. (author), Ainslie, M.A. (author)Reliable predictions of sea-surface backscattering strength are required for sonar performance modeling. These are, however, difficult to obtain as measurements of sea-surface backscattering are not available at small grazing angles relevant to low-frequency active sonar (1-3 kHz). Accurate theoretical predictions of scattering strength require...article 2011
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Ainslie, M.A. (author), Leighton, T.G. (author)Perhaps the most familiar concepts when discussing acoustic scattering by bubbles are the resonance frequency for bubble pulsation, the bubbles' damping, and their scattering and extinction cross-sections, all of which are used routinely in oceanography, sonochemistry, and biomedicine. The apparent simplicity of these concepts is illusory: there...article 2011
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- Kastelein, R.A. (author), Hoek, L. (author), de Jong, C.A.F. (author) article 2011
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Wessels, P.W. (author), Basten, T.G.H. (author), van der Eerden, F.J.M. (author)In order to have a good understanding of the environmental acoustic effects of traffic it is important to perform long term monitoring within large areas. With traditional monitoring approaches this is quite unfeasible and the costs are relatively high. Within TNO a new wireless monitoring approach has been developed which is based on low cost...conference paper 2011
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van der Eerden, F.J.M. (author), van den Berg, F. (author)Semi-open shooting ranges, in contrast to a fully open shooting range, are often used in the densely populated area of the Netherlands. The Ministry of Defense operates a number of these ranges. In these shooting ranges above the line of fire a number of screens are situated for safety precautions to prevent bullets to exit the range. When a...conference paper 2011
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Zampolli, M. (author), Ainslie, M.A. (author)In April 2010, a symposium in Memory of David Weston was held at Clare College in Cambridge (UK). International researchers from academia and research laboratories met to discuss two sets of test problems for sonar performance models, one aimed at understanding mammal echolocation sonar („Problem AI‟), and the other at benchmarking low frequency...conference paper 2011
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Ainslie, M.A. (author), Leighton, T.G. (author)In [M. A. Ainslie & T. G. Leighton, Underwater Acoustic Measurements (Heraklion, Crete, 2007), pp 571-576], the authors described a discrepancy between the radiation damping coefficients in the models due to Weston and to Medwin describing the scattering cross-section of a single spherical bubble. The resolution of that discrepancy [M. A....conference paper 2011
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Ainslie, M.A. (author), Dekeling, R.P.A. (author)Cumulative acoustic exposure is used as an indicator for the risk of negative impact to animals as a consequence of exposure to underwater sound. The free-field energy of a single source, defined as the total acoustic energy that would exist in the source’s free field, is shown to be closely related to the total cumulative exposure added over a...conference paper 2011
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Ainslie, M.A. (author), Harrison, C.H. (author), Zampolli, M. (author)Previously published equations for the time dependence of the echo and reverberation in a Pekeris waveguide are combined with an expression derived for surface-generated noise. These closed form solutions are applied to the calculation of signal to reverberation ratio and signal to total background ratio for three CW pulses with centre...conference paper 2011
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Volker, A.W.F. (author), Hunter, A.J. (author)Anisotropic materials are being used increasingly in high performance industrial applications, particularly in the aeronautical and nuclear industries. Some important examples of these materials are composites, single-crystal and heavy-grained metals. Ultrasonic array imaging in these materials requires exact knowledge of the anisotropic...conference paper 2011
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Ainslie, M.A. (author), Jong C.A.F. de, (author), Dreschler, J. (author)Ambient noise in the frequency range 25 Hz to 80 kHz was measured at a site close to the Port of Rotterdam in September 2008, before construction began of a port extension known as ‘Maasvlakte 2’ [http://www.maasvlakte2.com/en/index/], and in September-October 2009 (during construction). Day-night differences are present in the 2009 measurements...conference paper 2011
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Quesson, B.A.J. (author), van Vossen, R. (author), Zampolli, M. (author), Beckers, A.L.D. (author)The aim of the Mine Underwater Detection (MUD) project at TNO is to experimentally investigate the acoustic and magnetic detection of explosives underwater, buried in a soft sediment layer. This problem is relevant for the protection of harbors and littoral assets against terrorist attacks and for the detection of underwater unexploded ordnance ...conference paper 2011
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Zampolli, M. (author), Ainslie, M.A. (author), van Zon, T. (author)Ping-to-ping variations in echo level can be caused by time variations in sonar parameters (source level, orientation), target aspect, relative and absolute motion of sonar and target, and time varying environment (e.g. surface waves). Quantifying and understanding such fluctuations are important, since they enable an appropriate choice of...conference paper 2011
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Fillinger, L. (author), Hunter, A.J. (author), Zampolli, M. (author), Clarijs, M.C. (author), Verolme, J.L. (author)Divers and small vessels are increasingly recognized as a potential threat to high value assets. Harbour and waterside surveillance systems that are used to counter the threat of divers are usually based on active sonar, whose performance can be limited by reverberation in a harbour environment. Passive techniques are based on the detection of...conference paper 2011
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Fillinger, L. (author), Hunter, A.J. (author), Zampolli, M. (author), Clarijs, M.C. (author), Verolme, J.L. (author)Situation awareness is an important component of security that justifies the equipment of sites with monitoring systems. For shore/harbour security, these systems are mostly composed of camera and radar, to monitor the land and the water surface, and of active sonar(s) when the underwater situation is monitored. An alternate approach for...conference paper 2011
Searched for: subject%3A%22AS%255C%2B%255C-%255C%2BAcoustics%255C%2B%2526%255C%2BSonar%22
(301 - 320 of 342)