Searched for: subject%3A%22AS%255C%2B%255C-%255C%2BAcoustics%255C%2B%2526%255C%2BSonar%22
(281 - 300 of 342)
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Dol, H. (author), van Walree, P. (author)This paper provides an overview of more than 12 years of underwater acoustic communication research at the Sonar Department of TNO The Hague. The research covered both point-to-point links and relay networks, from long-range covert communication to short-range high-data-rate communication, for both civil and military applications. The current...conference paper 2011
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Tang, Z. (author), Blacquière, G. (author), Leus, G. (author)Sparse signal representation (SSR) is considered to be an appealing alternative to classical beamforming for direction-of-arrival (DOA) estimation. For wideband signals, the SSR-based approach constructs steering matrices, referred to as dictionaries in this paper, corresponding to different frequency components of the target signal. However,...article 2011
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Basten, T.G.H. (author), Wessels, P.W. (author), van der Eerden, F.J.M. (author)Having a good understanding of the environmental acoustic effects of traffic in urban areas is important but still a difficult task. Long term monitoring within large areas is needed to provide actual data for taking appropriate and cost efficient measures; to asses the effect of measures by comparing before and after implementation and to have...conference paper 2011
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Juhel, B. (author), Cristol, X. (author), Chalindar, B. (author), Dybedal, J. (author), Eidem, E.J. (author), Ivansson, S. (author), van Vossen, R. (author), Ainslie, M.A. (author), Andersson, B.L. (author), Benders, F.P.A. (author), Colin, M.E.G.D. (author), Olsen, G.K. (author), Pihl, J. (author)This paper presents the European Defence Agency project called “RUMBLE 2” carried out with contribution of several European organizations: TUS in France, TNO in the Netherlands, KDS and FFI in Norway, FOI in Sweden. The objective was to assess the capability of an operational Low Frequency Active Sonar (LFAS) to estimate bottom parameters in...conference paper 2011
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- de Roo, F. (author), Dittrich, M.G. (author), van Beek, P.J.G. (author), Bosschaert, C. (author), Derksen, G.B. (author), de Kievit, M. (author) conference paper 2011
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Lutgendorf, D. (author), de Roo, F. (author), van der Eerden, F.J.M. (author), Jean, P. (author), Ecotière, D. (author), Dutilleux, G. (author)This paper deals with the first stages of the development of a new test method for evaluating the reflectivity performance of noise barriers. The reflectivity performance describes the increase in sound level at a receiver due to the presence of the noise barrier. First the current test method for sound reflectivity is simulated with three...conference paper 2011
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van den Berg, F. (author), van der Eerden, F.J.M. (author)Much environmental research is performed on predicting the noise impact of heavy weapons or explosives, as the shock waves can propagate over large distances. In the densely populated area of the Netherlands this is of particular interest for the Ministry of Defense. In one research program the mitigation of shock waves close to the source has...conference paper 2011
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van Capel, P.J.S. (author), van Vossen, R. (author), Volker, A.W.F. (author)The application of phased arrays in NDT applications is growing. State of the art ultrasonic arrays consist of many small piezo-electric elements that can be excited separately to synthesize a desired wave front. This may vary from simple plane waves to complex-shaped focusing wave fields. An implicit requirement is that the source strength ...conference paper 2011
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van Vossen, R. (author), Beerens, S.P. (author), van der Spek, E. (author)Existing surveillance sonar systems for anti-submarine warfare (ASW) use a pulsed sonar deployed at a low duty cycle. Continuously active sonar (CAS) is of special interest since the technique could provide better detection performance than conventional pulsed sonar, and it will provide the operator a continuous track. One can assume this will...article 2011
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Berkhoff, A.P. (author)Model errors in adaptive controllers for reduction of broadband noise and vibrations may lead to unstable systems or increased error signals. Previous work has shown that the addition of a low-authority controller that increases damping in the system may lead to improved performance of an adaptive, high-authority controller. Other researchers...conference paper 2011
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Hunter, A.J. (author), Drinkwater, B.W. (author), Wilcox, P.D. (author)Ultrasonic array images are adversely affected by errors in the assumed or measured imaging parameters. For non-destructive testing and evaluation, this can result in reduced defect detection and characterization performance. In this paper, an autofocus algorithm is presented for estimating and correcting imaging parameter errors using the...article 2011
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Clairbois, J.-P. (author), de Roo, F. (author), Garai, M. (author), Conter, M. (author), Defrance, J. (author), Oltean-Dumbrava, C. (author), Fusco, I. (author)The research QUIESST (QUIetening the Environment of Sustainable Surface Transport) successfully started in November 2009 for 36 months, its objectives and work schedule have already been presented at the INTERNOISE 2010 Congress. This paper will present the progress report at mid-term (18 months): the technical work packages are WP2 ...conference paper 2011
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Zhang, N. (author), Millane, R. (author), Hunter, A.J. (author), Enevoldson, E. (author), Murray, J.E. (author)The problem of estimating wind velocities from limited flight data recordings is considered, with application to sailplane flights in high-altitude mountain waves. Sailplane flight recorders routinely measure only GPS position and, infrequently, also airspeed and the problem is underdetermined. Maximum likelihood and maximum a posteriori...conference paper 2011
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Kastelein, R.A. (author), Wensveen, P.J. (author), Terhune, J.M. (author), de Jong, C.A.F. (author)Equal-loudness functions describe relationships between the frequencies of sounds and their perceived loudness. This pilot study investigated the possibility of deriving equal-loudness contours based on the assumption that sounds of equal perceived loudness elicit equal reaction times (RTs). During a psychoacoustic underwater hearing study, the...article 2011
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Booij, P.S. (author), Berkhoff, A.P. (author)This paper presents various experimental results of a real-time, multiple-channel, broadband Active Noise Control (ANC) system, employing the Remote Microphone Technique (RMT) as virtual sensing algorithm in different settings. The effects of virtual sensing on the shape and size of the quiet zone are experimentally investigated. To enhance the...conference paper 2011
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van Vossen, R. (author), van der Spek, E. (author), Beerens, S.P. (author)Existing sonar systems are commonly deployed at a low duty cycle, i.e. a short transmit signal is used followed by a long listening time. As a result, the target is only illuminated during a short time resulting in only one detection opportunity per ping. When a sonar system is capable of recording meaningful data during its transmission, one...conference paper 2011
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Reinink, F. (author), van Blokland, G. (author), de Roo, F. (author), Derksen, G.B. (author)The CPX method (ISO/CD 11819-2) is regularly used for assessing the acoustic quality of road surface within the frame work of checking with compliance to contract requirements nd conformity-of-production. The reproducibility of the test procedure is investigated ith a Round Robin test in which 7 operators of CPX systems, coming from Belgium,...conference paper 2011
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von Benda-Beckmann, A.M. (author), Beerens, S.P. (author), Teters, T. (author), Karrels, J. (author), Don Carlos, J. (author)This paper addresses the localization of active sonar signals that are encountered in the international submarine community with the function of Acoustic Intercept Ranging. An Intercept ranging system was developed by ISL (USA) and TNO (The Netherlands), where ISL was responsible for the system design, the hardware and the integration and TNO...conference paper 2011
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Colin, M.E.G.D. (author), Beerens, S.P. (author)In the last two decades, low-frequency active sonar (LFAS) emerged as one of the most efficient tools for shallow-water antisubmarine warfare (ASW). Like any long-range active sonar system, LFAS produces a large amount of unwanted sea bottom echoes or clutter. These echoes give way to false alarms that increase the computational load of target...article 2011
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Kastelein, R.A. (author), Hoek, L. (author), de Jong, C.A.F. (author)The distance at which active naval sonar signals can be heard by harbor porpoises depends, among other factors, on the hearing thresholds of the species for those signals. Therefore the hearing sensitivity of a harbor porpoise was determined for 1 s up-sweep and down-sweep signals, mimicking mid-frequency and low-frequency active sonar sweeps ...article 2011
Searched for: subject%3A%22AS%255C%2B%255C-%255C%2BAcoustics%255C%2B%2526%255C%2BSonar%22
(281 - 300 of 342)