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Sun, L.G. (author), De Visser, C.C. (author), Chu, Q.P. (author), Mulder, J.A. (author)The optimality of the kernel number and kernel centers plays a significant role in determining the approximation power of nearly all kernel methods. However, the process of choosing optimal kernels is always formulated as a global optimization task, which is hard to accomplish. Recently, an algorithm, namely improved recursive reduced least...journal article 2012
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Driessen, E.F.C. (author), Coumou, P.C.J.J. (author), Tromp, R.R. (author), De Visser, P.J. (author), Klapwijk, T.M. (author)We probe the effects of strong disorder (2.4<kFl<8.6) on superconductivity in thin films of niobium titanium nitride and titanium nitride by measuring the microwave electrodynamics in coplanar waveguide resonators. We find a gradual evolution of the electromagnetic response with disorder, deviating from BCS theory, for both materials. This...journal article 2012
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De Visser, P.J. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Diener, P. (author), Endo, A. (author), Klapwijk, T.M. (author)We have measured the number of quasiparticles and their lifetime in aluminium superconducting microwave resonators. The number of excess quasiparticles below 160?mK decreases from 72 to 17??m?3 with a 6?dB decrease of the microwave power. The quasiparticle lifetime increases accordingly from 1.4 to 3.5?ms. These properties of the superconductor...journal article 2012
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Baselmans, J. (author), Yates, S. (author), Diener, P. (author), De Visser, P. (author)The next generation of far infrared radiation detectors is aimed to reach photon noise limited performance in space based observatories such as SPICA and BLISS. These detectors operate at loading powers of the astronomical signal of a few Attowatt (10?18 W) or less, corresponding to a sensitivity expressed in noise equivalent power as low as NEP...journal article 2012
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Endo, A. (author), Van der Werf, P. (author), Janssen, R.M.J. (author), De Visser, P.J. (author), Klapwijk, T.M. (author), Baselmans, J.J.A. (author), Ferrari, L. (author), Baryshev, A.M. (author), Yates, S.J.C. (author)An integrated filterbank (IFB) in combination with microwave kinetic inductance detectors (MKIDs), both based on superconducting resonators, could be used to make broadband submillimeter imaging spectrographs that are compact and flexible. In order to investigate the possibility of adopting an IFB configuration for DESHIMA (Delft SRON High...journal article 2012
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De Visser, P.J. (author), Baselmans, J.J.A. (author), Diener, P. (author), Yates, S.J.C. (author), Endo, A. (author), Klapwijk, T.M. (author)We present measurements of quasiparticle generation-recombination noise in aluminium Microwave Kinetic Inductance Detectors, the fundamental noise source for these detectors. Both the quasiparticle lifetime and the number of quasiparticles can be determined from the noise spectra. The number of quasiparticles saturates to 10 ?m?3 at temperatures...journal article 2012
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Janssen, R.M.J. (author), Endo, A. (author), Baselmans, J.J.A. (author), De Visser, P.J. (author), Barends, R. (author), Klapwijk, T.M. (author)The sensitivity of microwave kinetic inductance detectors (MKIDs) based on coplanar waveguides (CPWs) needs to be improved by at least an order of magnitude to satisfy the requirements for space-based terahertz astronomy. Our aim is to investigate if this can be achieved by reducing the width of the CPW to much below what has typically been made...journal article 2012
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De Visser, C.C. (author), Mulder, J.A. (author)The validation of aerodynamic models created using flight test data is a time consuming and often costly process. In this paper a new method for the validation of global nonlinear aerodynamic models based on multivariate simplex splines is presented. This new method uses the unique properties of the multivariate simplex splines, a recent type of...conference paper 2011
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De Visser, C.C. (author)At present, model based control systems play an essential role in many aspects of modern society. Application areas of model based control systems range from food processing to medical imaging, and from process control in oil refineries to the flight control systems of modern aircraft. Central to a model based control system is a mathematical...doctoral thesis 2011
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De Visser, C.C. (author), Chu, Q.P. (author), Mulder, J.A. (author)The ability to perform online model identification for nonlinear systems with unknown dynamics is essential to any adaptive model-based control system. In this paper, a new differential equality constrained recursive least squares estimator for multivariate simplex splines is presented that is able to perform online model identification and...journal article 2011
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De Visser, P.J. (author), Baselmans, J.J.A. (author), Diener, P. (author), Yates, S.J.C. (author), Endo, A. (author), Klapwijk, T.M. (author)We have directly measured quasiparticle number fluctuations in a thin film superconducting Al resonator in thermal equilibrium. The spectrum of these fluctuations provides a measure of both the density and the lifetime of the quasiparticles. We observe that the quasiparticle density decreases exponentially with decreasing temperature, as...journal article 2011
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De Visser, P.J. (author), Withington, S. (author), Goldie, D.J. (author)A model is presented for readout-power heating in kinetic inductance detectors. It is shown that the power dissipated by the readout signal can cause the temperature of the quasiparticle system in the superconducting resonator to switch between well-defined states. At low readout powers, only a single solution to the heat balance equation exists...journal article 2010
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De Visser, C.C. (author), Mulder, J.A. (author)A new method is proposed for the identification of global nonlinear models of aircraft non-dimensional force and moment coefficients. The method is based on a recent type of multivariate spline, the multivariate simplex spline, which can accurately approximate very large, scattered nonlinear datasets in any number of dimensions. The new...conference paper 2010
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Barends, R. (author), Vercruyssen, N. (author), Endo, A. (author), De Visser, P.J. (author), Zijlstra, T. (author), Klapwijk, T.M. (author), Baselmans, J.J.A. (author)We report a reduction in the frequency noise in coplanar waveguide superconducting resonators. The reduction of 7 dB is achieved by removing the exposed dielectric substrate surface from the region with high electric fields and by using NbTiN. In a model-analysis the surface of NbTiN is found to be a negligible source of noise, experimentally...journal article 2010
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Barends, R. (author), Vercruyssen, N. (author), Endo, A. (author), De Visser, P.J. (author), Zijlstra, T. (author), Klapwijk, T.M. (author), Diener, P. (author), Yates, S.J.C. (author), Baselmans, J.J.A. (author)We report quality factors of up to 500x10³ in superconducting resonators at the single photon levels needed for circuit quantum electrodynamics. This result is achieved by using NbTiN and removing the dielectric from regions with high electric fields. As demonstrated by a comparison with Ta, the crucial sources of intensity-dependent loss are...journal article 2010
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De Visser, C.C. (author), Chu, Q.P. (author), Mulder, J.A. (author)A new methodology for creating highly accurate, static nonlinear maps from scattered, multivariate data is presented. This new methodology uses the B-form polynomials of multivariate simplex splines in a new linear regression scheme. This allows the use of standard parameter estimation techniques for estimating the B-coefficients of the...journal article 2009
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- Blaauboer, M. (author), De Visser, R.L. (author) journal article 2008
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- Reyal, F. (author), Van Vliet, M.H. (author), Armstrong, N.J. (author), Horlings, H.M. (author), De Visser, K.E. (author), Kok, M. (author), Teschendorff, A.E. (author), Mook, S. (author), Van 't Veer, L. (author), Caldas, C. (author), Salmon, R.J. (author), Vijver, M.J. (author), Wessels, L.F.A. (author) journal article 2008
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- De Visser, M. (author), Schwering, P.B.W. (author), De Groot, J.F. (author), Hendriks, E.A. (author) journal article 2006
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- De Visser, J. (author), Wieringa, P.A. (author), Moss, J. (author), Xiao, Y. (author) conference paper 2002