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Malgoezar, A.M.N. (author), Snellen, M. (author), Sijtsma, P. (author), Simons, D.G. (author)
Assigning proper positions to microphones within arrays is essential in order to reduce or eliminate side- and grating lobes in 2D beamform images. In this paper an objective function is derived providing a measure for the presence of artificial sources. Using the global optimization method Differential Evolution an optimized microphone...
conference paper 2016
document
Sijtsma, P. (author), Snellen, M. (author)
In this paper a high-resolution extension of CLEAN-SC is proposed: HR-CLEAN-SC. Where CLEAN-SC uses peak sources in “dirty maps” to define so-called source components, HR-CLEAN-SC takes advantage of the fact that source components can likewise be derived from points at some distance from the peak, as long as these “source markers” are on the...
conference paper 2016
document
Merino Martinez, R. (author), Snellen, M. (author), Simons, D.G. (author)
Aircraft noise is becoming an increasingly important problem for the aerospace industry and for the residents living in the vicinities of airports. For efforts aiming at reducing aircraft noise levels, it is important to know all the aircraft elements which generate noise and their relative contribution. Experimental measurements with aircraft...
conference paper 2016
document
Blinstrub, J. (author), Heinze, W (author), Bertsch, E.L. (author), Simons, D.G. (author), Snellen, M. (author)
An innovative aircraft design of the Collaborative Research Centre (SFB) 880 features a new active high-lift system. This high-lift system is comprised of a droop-nose leading edge device and a Coanda flap as the trailing edge device. It offers very high lift coefficients and thus the ability to operate at airports that have reduced runway...
conference paper 2016
document
Malgoezar, A.M.N. (author), Snellen, M. (author), Simons, D.G. (author), Sijtsma, P. (author)
Conventional beamforming is a common method to localize sound sources with a microphone array. The method, which is based on the delay-and-sum beamforming, provides an estimate value for the source strength at a given spatial position. It suffers from low spatial resolution at low frequencies, high side lobe levels and requires the user to...
conference paper 2016
document
Merino Martinez, R. (author), Snellen, M. (author), Simons, D.G. (author)
Airframe noise is becoming increasingly important during approach, even reaching higher noise levels than the engines in some cases. More people are a_ected due to low ight altitudes and _xed tra_c routing associated with typical approaches. For most air- craft types, the landing gear system is a dominant airframe noise source. However, this...
conference paper 2016
document
Merino Martinez, R. (author), Snellen, M. (author), Simons, D.G. (author)
Nowadays, aircraft noise is one of the major problems to be dealt with by the aerospace industry and especially suffered by the residents living in the vicinities of airports. The enforcement of noise control environmental laws around airports is hindered due to the large variability observed in the noise levels for flyovers of the same aircraft...
conference paper 2016
document
Snellen, M. (author), Merino Martinez, R. (author), Simons, D.G. (author)
Noise assessment around airports is hampered due to the observed large variability in noise levels for fly-overs of the same aircraft type, which is not considered by the current models. This paper assumes that the noise variability is due to variations in the aircraft emitted noise, neglecting the effect of the variable atmosphere, as previous...
conference paper 2015
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Sinnige, T. (author), Malgoezar, A.M.N. (author), Ragni, D. (author), Snellen, M. (author), Eitelberg, G. (author), Veldhuis, L.L.M. (author)
An experimental investigation was performed at the Large Low-speed Facility of the German-Dutch wind tunnels (DNW-LLF) to study the pylon interactions associated with pusher propellers. The aerodynamic and aeroacoustic effects of pylon trailing edge blowing and swirl recovery vanes (SRVs) were evaluated. The pylon installation increased the...
conference paper 2015
document
Orru, C. (author), Eleftherakis, D. (author), Blom, A. (author), Snellen, M. (author), Uijttewaal, W.S.J. (author), Simons, D.G. (author)
Grain size changes in a river dominated by mixed sediment are the outcome of sedimentary grain sizeselective processes. Progress in the measurement techniques that define the spatial and temporal variation in grain size is necessary to provide new insights in this field. Techniques as image analysis and acoustic methods have emerged in the last...
conference paper 2013
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Kinneging, N. (author), Snellen, M. (author), Eleftherakis, D. (author), Simons, D.G. (author), Mosselman, E. (author), Siben, A. (author)
The Netherlands form the delta for some of the major river systems of Europe, comprising the Rhine, the Meuse, the Scheldt and the Eems. These rivers are valuable parts of national and international ecological networks and are of high economic importance. A minimum depth should be guaranteed to keep the rivers navigable. This depth depends not...
conference paper 2012
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Siemes, K. (author), Snellen, M. (author), Simons, D.G. (author), Hermand, J.P. (author)
Shallow water naval operations require detailed knowledge of the environmental characteristics. In this context, the BP’07 experiment was carried out in the Mediterranean Sea, south-east of Elba Island, in 2007. Measurements that were taken during this experiment employ a large set of sensors, thereby providing all information required to fully...
conference paper 2009
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Snellen, M. (author), Siemes, K. (author), Simons, D.G. (author)
We present a method for accurately estimating the bathymetry from multi-beam echo-sounder (MBES) travel-time measurements in environments with large variations in the water column sound speeds (both temporally and spatially). In this type of environments the water column sound speeds at the time of the MBES transmission are often not known,...
conference paper 2009
document
Siemes, K. (author), Snellen, M. (author), Simons, D.G. (author), Hermand, J.P. (author)
Shallow water naval operations require detailed knowledge of the environmental properties. In addition to parameters such as water depth, knowledge about the sediment properties is of high importance for a wide range of operations. In this context, the MREA BP'07 experiment was carried out in the Mediterranean Sea in 2007. Measurements employed...
conference paper 2009
document
Snellen, M. (author), Siemes, K. (author), Simons, D.G. (author)
Nowadays extensive use is made of multibeam echosounders (MBES) for mapping the bathymetry of sea- and river-floors. The MBES is capable of covering large areas in limited time by emitting an acoustic pulse along a wide swathe perpendicular to the sailing direction. The angle and the corresponding two-way travel-time of the received signals are...
conference paper 2009
document
Amiri-Simkooei, A.R. (author), Snellen, M. (author), Simons, D.G. (author)
In a recent work described in Ref. [1], an angle-independent methodology was developed to use the multi-beam echo sounder backscatter (MBES) data for the seabed sediment classification. The method employs the backscatter data at a certain angle to obtain the number of sediment classes and to discriminate between them by applying the Bayes...
conference paper 2009
document
Simons, D.G. (author), Snellen, M. (author), Siemes, K. (author)
Seafloor characterization is important in many fields including hydrography, marine geology, coastal engineering and habitat mapping. The advantage of non-invasive acoustic methods for sediment characterization over conventional bottom grabbing is the nearly continuous versus sparse sensing and the enormous reduction in survey time and costs....
conference paper 2009
document
Karimi Nejadasl, F. (author), Gorte, B.G.H. (author), Snellen, M.M. (author), Hoogendoorn, S.P. (author)
In this paper, we address the registration of two images as an optimization problem within indicated bounds. Our contribution is to identify such situations where the optimum value represents the real transformation parameters between the two images. Consider for example Mean Square Error (MSE) as the energy function: Ideally, a minimum in MSE...
conference paper 2008
document
Amiri-Simkooei, A. (author), Snellen, M. (author), Simons, D.G. (author)
conference paper 2008
document
Simons, D.G. (author), Snellen, M. (author)
conference paper 2008
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