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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
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Alevizos, Evangelos (author), Siemes, K. (author), Janmaat, J. (author), Snellen, M. (author), Simons, D.G. (author), Greinert, J (author)Quantitative mapping of seafloor sediment properties (eg. grain size) requires the input of comprehensive Multi-Beam Echo Sounder (MBES) datasets along with adequate ground truth for establishing a functional relation between them. MBES surveys in extensive shallow shelf areas can be a rather challenging and time-consuming task, resulting in...poster 2016
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Simons, E.C. (author), Weerheijm, J. (author), Sluys, Lambertus J. (author)The Johnson-Holmquist-2 ceramic model is used for quasi-static indentation simulation. A modification is proposed to an associated plasticity formulation. This allows for a fully implicit solution scheme, where dilatation is used instead of the traditional explicit bulking formulation. Dilatation is shown to have an important influence on ring...conference paper 2016
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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
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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
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- Snellen, M. (author), Simons, D.G. (author) journal article 2016
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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
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Sahai, A.K. (author), Simons, D.G. (author)This paper aims to present a way with which audible differences in measured and auralized (i.e. aurally simulated) aircraft noise can be quantified. The purpose of the study is to find a means with which the subjective differences between measured and synthesized sounds can be expressed in an objective manner. The quantification would firstly...conference paper 2016
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Merino Martinez, R. (author), Snellen, M. (author), Simons, D.G. (author)Functional beamforming is a state-of-the-art nonlinear algorithm based on the conventional frequency domain beamformer. In general, it is found to provide improved array spatial resolution and dynamic range. The computational time required for the functional beamforming is approximately the same as that for the conventional frequency domain...journal article 2016
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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
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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
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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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Arntzen, M. (author), Bertsch, E.L. (author), Simons, D.G. (author)A joint initiative of NLR, DLR, and TU Delft has been initiated to streamline the process of generating audible impressions of novel aircraft configurations. The integrated approach adds to the value of the individual tools and allows predicting the sound of future aircraft before they actually fly. Hence, an existing process for the aircraft...conference paper 2015
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Postseismic GRACE and GPS observations indicate a rheology contrast above and below the Sumatra slabBroerse, D.B.T. (author), Riva, R.E.M. (author), Simons, W.J.F. (author), Govers, R. (author), Vermeersen, L.L.A. (author)More than 7 years of observations of postseismic relaxation after the 2004 Sumatra-Andaman earthquake provide an improving view on the deformation in the wide vicinity of the 2004 rupture. We include both Gravity Recovery and Climate Experiment (GRACE) gravity field data that show a large postseismic signal over the rupture area and GPS...journal article 2015
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- Bertsch, E.L. (author), Simons, D.G. (author), Snellen, M. (author) report 2015
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Simons, L.P.A. (author), Foerster, F. (author), Bruck, P.A. (author), Motiwalla, L. (author), Jonker, C.M. (author)Work place health support interventions can help support our aging work force, with mApps offering cost-effectiveness opportunities. Previous research shows that health support apps should offer users enough newness and relevance each time they are used. Otherwise the ‘eHealth law of attrition’ applies: 90 % of users are lost prematurely. Our...journal article 2015
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Bertsch, E.L. (author), Simons, D.G. (author), Snellen, M. (author)I n October 2014, the first "Joint DLR & TU Delft Aviation Noise Workshop" was organized. This publication is the executive summary of this event. Overall, 38 invited participants f r om industry, academia, and research institutions have discussed the specific topic of this first 3 day workshop, i.e. "Aircraft Noise Reduction at the Source"....report 2015
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Fricke, J.T. (author), Evers, L.G. (author), Smets, P.S.M. (author), Wapenaar, C.P.A. (author), Simons, D.G. (author)We present the results of infrasonic interferometry applied to microbaroms, obtained from ambient noise. For this purpose the “Large Aperture Infrasound Array” (LAIA) was used, which has been installed in the Netherlands. Preprocessing appeared to be an essential step in enhancing the microbarom signals from ambient noise that strongly...journal article 2014
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Simons, C.A.B.A.E. (author), Sanabria-Walter, C. (author), Polinder, H. (author)During the past decades, superconducting electrical machines have become more suitable to replace conventional iron based designs, because of their lower weight and higher torque density. These properties make them good candidates for use in More Electric Aircraft (MEA). Especially helicopter propulsion systems could benefit from the increased...conference paper 2014
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Fricke, J.T. (author), El Allouche, N. (author), Simons, D.G. (author), Ruigrok, E.N. (author), Wapenaar, C.P.A. (author), Evers, L.G. (author)The atmospheric wind and temperature can be estimated through the traveltimes of infrasound between pairs of receivers. The traveltimes can be obtained by infrasonic interferometry. In this study, the theory of infrasonic interferometry is verified and applied to modeled stratospherically refracted waves. Synthetic barograms are generated using...journal article 2013