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Shigapov, R. (author), Kashtan, B. (author), Droujinine, A. (author), Mulder, W.A. (author)We consider the problem of anelastic full waveform inversion in a multi-layered, isotropic viscoelastic medium from microseismic and cross-hole perforation shots. Usually, the source wavelet is not well known, so we focus on Q estimation techniques that can handle this problem. We revisit the spectral ratio method (SRM) and discuss its domain of...journal article 2013
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Anikiev, D. (author), Kashtan, B. (author), Mulder, W.A. (author)Three model parameters as a function of position describe wave propagation in an isotropic elastic medium. Ideally, imaging of data for a point scatterer that consists of a perturbation in one of the elastic parameters should only provide a reconstruction of that perturbation, without cross-talk into the other parameters. This is not the case...journal article 2013
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- Caetano, J.V. (author), Verboom, J. (author), De Visser, C.C. (author), De Croon, G.C.H.E. (author), Remes, B.D.W. (author), De Wagter, C. (author), Mulder, M. (author) conference paper 2013
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Ponomarenko, A.V. (author), Kashtan, B.M. (author), Troyan, V.N. (author), Mulder, W.A. (author)Recently, we proposed an analytical approach to invert for a smoothly varying near-surface P-wave velocity profile that has a squared slowness linearly decreasing with depth. The exact solution for such a velocity profile in the acoustic approximation can be expressed in terms of Airy functions and leads to a dispersion equation. The method was...conference paper 2013
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Mostert-van der Sar, M. (author), Mulder, I.J. (author), Remijn, L. (author), Troxler, P. (author)The third industrial revolution, triggered by Internet communication and renewable energies, can be experienced in so-called FabLabs that empower users to ‘make almost anything’. Although this does not change the need for designers to have making and prototyping skills, there is no doubt the revolution impacts the design profession in terms of...conference paper 2013
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Online Aerodynamic Model Identification using a Recursive Sequential Method for Multivariate SplinesSun, L.G. (author), De Visser, C.C. (author), Chu, Q.P. (author), Mulder, J.A. (author)Avoiding high computational loads is essential to online aerodynamic model identi- fication algorithms, which are at the heart of any model-based adaptive flight control system. Multivariate simplex B-spline (MVSB) methods are excellent function approximation tools for modeling the nonlinear aerodynamics of high performance aircraft. However,...journal article 2013
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Mulder, F.A. (author), Verlinden, J.C. (author)To train competitive sailing in a virtual setting, motion of the boat as well as haptic feedback of the sail lines is essential. When discussing virtual environments (VEs) the concept of presence is often used. In this study we develop a sailing simulator motion system to research what factors contribute to the participants’ sensation of...journal article 2013
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Verlinden, J.C. (author), Mulder, F.A. (author), Vergeest, J.S. (author), De Jonge, A. (author), Krutiy, D. (author), Nagy, Z. (author), Logeman, B.J. (author), Schouten, P. (author)In the context of sailing, wind plays an important role. However, there is little knowledge on how wind influences presence – the sense of “being there” - while immersed in a virtual setting. This article explores several wind parameters and presents a wind array to explore presence in a sail simulator. The simulation offered a virtual training...journal article 2013
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Mulder, A. (author)When cities started shrinking, governments felt they had to do something. Where the main reason for shrinking was the closing down of traditional industry, economic policies were the first to be introduced: first by subsidising and reorganising existing companies, later by trying to create a more diverse employment structure. Gradually it was...conference paper 2013
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Mulder, J.W. (author), Mulder, I.J. (author), Best, S.E. (author)The current work introduces pursenality, a photoethnographic method for self-elicitation and cocreation, which elaborates upon current photography methods used in (design) ethnography. In total 91 bachelor students in the 6th semester participated in a purse diary study and used the pursenality method to gain rich insights informing their human...conference paper 2013
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Mulder, W.A. (author)Migration velocity analysis for the two-way wave equation based on focusing extended migration images at zero subsurface offset are sensitive to the presence of multiples. Even after thorough multiple suppression, remnant multiple energy can lead to conflicting events that will focus at different velocities, one for the primary and another for...conference paper 2013
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Mulder, W.A. (author)Mass-lumped continuous finite elements provide accurate solutions of the second-order acoustic or elastic wave equation in complex geological settings, in particular in the presence of topography and large impedance contrasts. Elements of higher polynomial degree have better accuracy than those of lower degree but are also more costly. Here, the...conference paper 2013
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Ponomarenko, A.V. (author), Kashtan, B.M. (author), Troyan, V.N. (author), Mulder, W.A. (author)Surface waves can be used to obtain a near-surface shear wave profile. The inverse problem is usually solved for the locally 1-D problem of a set of homogeneous horizontal elastic layers. The output is a set of shear velocity values for each layer in the profile. P-wave velocity profile can be estimated if higher modes and P-guided waves are...conference paper 2013
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Kazei, V. (author), Kashtan, B.M. (author), Troyan, V.N. (author), Mulder, W.A. (author)Full waveform inversion suffers from local minima, due to a lack of low frequencies in the data. A reflector below the zone of interest may help in recovering the long-wavelength components of a velocity perturbation, as demonstrated in a paper by Mora. Because smooth models are more popular as initial guesses for FWI, we consider the Born...conference paper 2013
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Stembert, N. (author), Mulder, I.J. (author)In the past years, governments have recognized the potential of interactive technology to bridge the gap with citizens. The right tools and guidance could enhance citizenship and enable co-creation between citizens and (local) governments. However, this opportunity does not automatically lead to a participatory practice. In the current article,...conference paper 2013
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Ellerbroek, J. (author), Brantegem, K.C.R. (author), Van Paassen, M.M. (author), Mulder, M. (author)This paper describes a concept for a coplanar airborne self-separation display, which is designed to aid pilots in their separation task, by visualizing the possibilities for conflict resolution that the airspace provides. This study is a part of an ongoing research toward the design of a constraint-based 3-D separation assistance interface that...journal article 2013
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Ellerbroek, J. (author), Brantegem, K.C.R. (author), Van Paassen, M.M. (author), Mulder, M. (author)Two experiments, an active conflict resolution task and a passive situation awareness assessment, were conducted that compared two versions of a constraint-based coplanar airborne separation assistance display. A baseline display showed a maneuver space based on 2-D projections of traffic and performance constraints. A second augmented display...journal article 2013
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Minisini, S. (author), Zhebel, E. (author), Kononov, A. (author), Mulder, W.A. (author)Modeling and imaging techniques for geophysics are extremely demanding in terms of computational resources. Seismic data attempt to resolve smaller scales and deeper targets in increasingly more complex geologic settings. Finite elements enable accurate simulation of time-dependent wave propagation in heterogeneous media. They are more costly...journal article 2013
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Kazei, V.V. (author), Kashtan, B.M. (author), Troyan, V.N. (author), Mulder, W.A. (author)It is generally believed that full waveform inversion needs very low frequencies in the data to avoid convergence to a local minimum, which would lead to an incorrect velocity model. Often, low frequencies are not present in the data. Then, a kinematically accurate initial model is required that contains the long-wavelength structures that...conference paper 2013
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Zlatanova, S. (author), Beetz, J. (author), Boersma, A.J. (author), Mulder, A. (author), Goos, J. (author)The maintenance of the complex infrastructure and facilities of Port of Rotterdam is based on large amounts of heterogeneous information. Almost all activities of the Port require spatial information about features above- and under- ground. Current information systems are department and data oriented and cannot reflect the new process- & project...conference paper 2013