Searched for: subject%3A%22integral%255C-equations%22
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Agresti, Antonio (author), Lindemulder, N. (author), Veraar, M.C. (author)
In this paper, we consider traces at initial times for functions with mixed time-space smoothness. Such results are often needed in the theory of evolution equations. Our result extends and unifies many previous results. Our main improvement is that we can allow general interpolation couples. The abstract results are applied to regularity...
journal article 2023
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Lv, Maolong (author), De Schutter, B.H.K. (author), Wang, Ying (author), Shen, Di (author)
This article attempts to realize zero-error constrained tracking for hypersonic flight vehicles (HFVs) subject to unknown control directions and asymmetric flight state constraints. The main challenges of reaching such goals consist in that addressing multiple unknown control directions requires novel conditional inequalities encompassing the...
journal article 2023
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Loreto, Fabrizio (author), Romano, Daniele (author), Antonini, Giulio (author), Stumpf, Martin (author), Lager, I.E. (author), Vandenbosch, Guy A.E. (author)
The critical relevance of ensuring the excitation's causality in electromagnetic (EM) simulations is exploited by the computation of strictly causal time domain interaction integrals as they occur in the partial element equivalent circuit (PEEC) method. Under the hypothesis of thin, almost zero thickness objects, the presented formulas represent...
conference paper 2022
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Steinbach, Olaf (author), Urzúa-Torres, Carolina (author)
We present a new approach for boundary integral equations for the wave equation with zero initial conditions. Unlike previous attempts, our mathematical formulation allows us to prove that the associated boundary integral operators are continuous and satisfy inf-sup conditions in trace spaces of the same regularity, which are closely related...
journal article 2022
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Ohm, Annerieke (author)
Metalenz is a spin­off company of Harvard University that works on finding newer and better designs for lenses. To prevent manufacturing designs that might not work, they first want to run computer simulations on their designs. This research focuses on a possible method for these simulations using a test case as design. It turns out that the...
bachelor thesis 2021
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Stumpf, Martin (author), Lager, I.E. (author), Antonini, Giulio (author), Vandenbosch, Guy A.E. (author)
Pulsed electromagnetic (EM) scattering from a relatively narrow superconducting strip is analyzed with the aid of the EM reciprocity theorem and the Cagniard-DeHoop (CdH) technique. The analysis yields a stable convolution-type equation that is solved using the marching-on-in-time (MOT) technique for coefficients representing the time-domain (TD...
conference paper 2021
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Dely, Alexandre (author), Andriulli, Francesco P. (author), Cools, K. (author)
The time domain-electric field integral equation (TD-EFIE) and its differentiated version are widely used to simulate the transient scattering of a time dependent electromagnetic field by a perfect electric conductor (PEC). The time discretization of the TD-EFIE can be achieved by a space-time Galerkin approach or, as it is considered in this...
journal article 2020
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Smirnova, Vera B. (author), Proskurnikov, A.V. (author)
In this paper, systems of nonlinear integro-differential Volterra equations are examined that can be represented as feedback interconnections of linear time-invariant block and periodic nonlinearities. The interest in such systems is motivated by their numerous applications in mechanical, electrical and communication engineering; examples...
journal article 2019
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Koolstra, K. (author)
Modeling electromagnetic fields in MRI involves two main challenges: the solution of the scattering problem resulting from Maxwell's equations has to be accurate and it has to be obtained within short computation time. In this thesis a method that meets both requirements is searched for. The method of moments with rooftop basis functions is used...
master thesis 2015
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Ozmen, N. (author), Dapp, R. (author), Zapf, M. (author), Gemmeke, H. (author), Ruiter, N.V. (author), Van Dongen, K.W.A. (author)
Ultrasound is frequently used to evaluate suspicious masses in breasts. These evaluations could be improved by taking advantage of advanced imaging algorithms, which become feasible for low frequencies if accurate knowledge about the phase and amplitude of the wave field illuminating the volume of interest is available. In this study, we compare...
journal article 2015
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Ozmen, N. (author)
The main focus of this thesis is on modeling acoustic wavefield propagation and implementing imaging algorithms for breast cancer detection using ultrasound. As a starting point, we use an integral equation formulation, which can be used to solve both the forward and inverse problems. This thesis contains three main topics: forward modeling,...
doctoral thesis 2014
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Van 't Wout, E. (author)
The aim of this thesis is to design a computational method that can be used in modern stealth technology. In particular, the computational method should be capable to simulate scattering of ultra-wideband radar signals for military aircraft constructed with ferromagnetic radar absorbent materials. A full-wave boundary element method has been...
doctoral thesis 2013
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Verweij, M.D. (author), Demi, L. (author), Van Dongen, K.W.A. (author)
The Iterative Nonlinear Contrast Source (INCS) method is a full-wave method for the accurate computation of wide-angle, pulsed, nonlinear ultrasound fields appearing in, e.g., medical echoscopy. The method is based on the Westervelt equation and considers the occurring nonlinear term as a distributed contrast source that operates in a linear...
conference paper 2012
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Zouros, G.P. (author), Budko, N.V. (author)
The domain integral equation method with its FFT-based matrix-vector products is a viable alternative to local methods in free-space scattering problems. However, it often suffers from the extremely slow convergence of iterative methods, especially in the transverse electric (TE) case with large or negative permittivity. We identify very dense...
journal article 2012
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Moradi Tehrani, A. (author)
In this study we developed algorithms for fast frequency and time domain integral equation modelling for marine controlled-source electromagnetic (CSEM) applications. Solutions of integral equations for CSEM applications in a three-layered earth with an assumed reservoirs is examined using the conjugate gradient fast Fourier transformation (CG...
doctoral thesis 2012
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Glavatskiy, K.S. (author), Bedeaux, D. (author)
In this paper we calculate the interfacial resistances to heat and mass transfer through a liquid–vapor interface in a binary mixture. We use two methods, the direct calculation from the actual nonequilibrium solution and integral relations, derived earlier. We verify, that integral relations, being a relatively faster and cheaper method, indeed...
journal article 2010
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Van der Toorn, R. (author), Zimmerman, J.T.F. (author)
On the basis of the angular momentum equation for a fluid shell on a rotating planet, we analyze the intrinsic drift of a monopolar vortex in the shell. Central is the development of a general angular momentum equation for Eulerian fluid mechanics based on coordinate-free, general tensorial representations of the underlying fluid dynamics on the...
journal article 2010
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De Hoop, A.T. (author), Abubakar, A. (author), Habashy, T.M. (author)
The contrast-source stress-velocity integral-equation formulation of three-dimensional time-domain elastodynamic scattering problems is discussed. A novel feature of the formulation is a tensor partitioning of the relevant dynamic stress and the contrast source volume density of deformation rate. The partitioning highlights several features...
journal article 2009
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Verweij, M.D. (author), Huijssen, J. (author)
The full-wave computation of transient acoustic fields with sizes in the order of 100x100x100 wavelengths by 100 periods requires a numerical method that is extremely efficient in terms of storage and computation. Iterative integral equation methods offer a good performance on these points, provided that the recurring spatiotemporal convolutions...
journal article 2009
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Hermans, A.J. (author)
journal article 2007
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