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Soft Layer: A work of art by Toshitaka Nishizawa for the Mijnbouwkundige Vereeniging

Jansen, J.D. (author), Blom, J.C. (author), Free, Renske (author), Kouwenhoven, Paula (author), Fokkema, J.T. (author), de Bruijn, Birgit (author), Smeulders, Julien (author), Drenth, D.J.H. (author), van der Kleijn, Piet Hein (author)

This booklet provides additional information to the work of art 'Soft Layer' located in front of the faculty of Civil Engineering and Geosciences. This piece of art is an initiative of students and alumni of the Mijnbouwkundige Vereeniging and has been revealed on the 24th of February, 2020.

other 2020

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On the Electromagnetic Propagation Paths and Wavefronts in the Vicinity of a Refractive Object

Fokkema, J.T. (author), van den Berg, Peter M. (author)

Maxwell's equations are transformed from a Cartesian geometry to a Riemannian geometry. A geodetic path in the Riemannian geometry is defined as the raypath on which the electromagnetic energy efficiently travels through the medium. Consistent with the spatial behavior of the Poynting vector, the metric tensor is required to be functionally...

journal article 2020

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Ultrasonic synthetic-aperture interface imaging

van der Neut, J.R. (author), Fokkema, J.T. (author), van den Berg, P.M. (author), Zapf, Michael (author), Ruiter, Nicole V. (author), Taskin, U. (author), van Dongen, K.W.A. (author)

Synthetic-aperture (SA) imaging is a popular method to visualize the reflectivity of an object from ultrasonic reflections. The method yields an image of the (volume) contrast in acoustic impedance with respect to the embedding. Typically, constant mass density is assumed in the underlying derivation. Due to the band-limited nature of the...

journal article 2019

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Partnerkeuze bij gebiedsontwikkeling: Houd het simpel: met vlag en wimpel

De Zeeuw, W.C.T.F. (author), Kersten, R.A.E.M. (author), Van der Hee, M. (author), Konings, B. (author), Fokkema, J. (author), Schepman, M.H.L. (author), Zandvliet, N. (author)

Een handreiking voor marktpartijen en overheden in het verlengde van de Reiswijzer Gebiedsontwikkeling 2011. Neprom en Akro Consult met medewerking van de Praktijkleerstoel Gebiedsontwikkeling, TU Delft.

report 2014

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An approximate 3D computational method for real-time computation of induction logging responses

Bensdorp, S. (author), Petersen, S.A. (author), Van den Berg, P.M. (author), Fokkema, J.T. (author)

Over many years, induction logging systems have been used to create well formation logs. The major drawback for the utilization of these tools is the long simulation time for a single forward computation. We proposed an efficient computational method based on a contrast-type of integral-equation formulation, in which we applied an approximation...

journal article 2014

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Wavefield decomposition based on acoustic reciprocity: Theory and applications to marine acquisition

Van Borselen, R.G. (author), Fokkema, J.T. (author), Van den Berg, P.M. (author)

In marine seismic acquisition, the free surface generates seismic events in our recorded data that are often categorized as noise because these events do not contain independent information about the subsurface geology. Ghost events are considered as such noise because these events are generated when the energy generated by the seismic source,...

journal article 2013

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De eerste ervaringen met de Crisis- en herstelwet

Barkhuysen, T. (author), Fokkema, M. (author), Kortmann, C.N.J. (author), Lurks, M. (author), De Zeeuw, W.C.T.F. (author)

journal article 2011

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Handboek wijkeconomie

Pijlman, L. (author), Van den Hazel, R. (author), Vaessen, M. (author), Nicasie, J. (author), Fokkema, M. (author), Borgmeijer, E. (author), Draaijer, P. (author), Nieuwenhuis, W. (author), Radstake, E. (author), Korthals Altes, W.K. (author), Louw, E. (author), De Wolff, H.W. (author), Van der Sluis - Van Meijeren, M. (author), Adriaanse, C.M.M. (author), Ouwehand, A.L. (author), Romein, A. (author), Trip, J.J. (author), Hoekstra, J.S.C.M. (author)

book 2010

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Brightness measurements of a gallium liquid metal ion source

Hagen, C.W. (author), Fokkema, E. (author), Kruit, P. (author)

The virtual source size of a liquid metal ion source is an order of magnitude larger than the size of the region from which the ions are emitted at the source. This source size has a direct effect on the reduced brightness and, hence, on the performance of these sources. The variation of the virtual source size of a gallium liquid metal ion...

journal article 2008

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Simulating migrated and inverted seismic data by filtering a geologic model

Toxopeus, G. (author), Thorbecke, J.W. (author), Wapenaar, C.P.A. (author), Petersen, S. (author), Slob, E.C. (author), Fokkema, J.T. (author)

The simulation of migrated and inverted data is hampered by the high computational cost of generating 3D synthetic data, followed by processes of migration and inversion. For example, simulating the migrated seismic signature of subtle stratigraphic traps demands the expensive exercise of 3D forward modeling, followed by 3D migration of the...

journal article 2008

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The Future needs innovative sustainable solutions. Dies speech.

Fokkema, J.T. (author)

public lecture 2007

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Plane-wave depth migration

Stoffa, P.L. (author), Sen, M.K. (author), Seifoullaev, R.K. (author), Pestana, R. (author), Fokkema, J.T. (author)

We present fast and efficient plane-wave migration methods for densely sampled seismic data in both the source and receiver domains. The methods are based on slant stacking over both shot and receiver positions (or offsets) for all the recorded data. If the data-acquisition geometry permits, both inline and crossline source and receiver...

journal article 2006

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Green's function representations for seismic interferometry

Wapenaar, C.P.A. (author), Fokkema, J.T. (author)

The term seismic interferometry refers to the principle of generating new seismic responses by crosscorrelating seismic observations at different receiver locations. The first version of this principle was derived by Claerbout (1968), who showed that the reflection response of a horizontally layered medium can be synthesized from the...

journal article 2006

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A new elastic model for ground coupling of geophones with spikes

Drijkoningen, G.G. (author), Rademakers, F. (author), Slob, E.C. (author), Fokkema, J.T. (author)

Ground coupling are terms that describe the transfer from seismic ground motion to the motion of a geophone. In previous models, ground coupling was mainly considered as a disk lying on top of a half-space, not considering the fact that in current practice geophones are spiked and are buried for optimal response. In this paper we introduce a new...

journal article 2006

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Challenge the Future

Fokkema, J.T (author)

Dies Natalis 164

public lecture 2006

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Disneyland

Fokkema, J.T. (author)

Gastschrijver TU Delft 2006

book 2006

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Retrieving the Green’s function in an open system by cross correlation: A comparison of approaches (L)

Wapenaar, C.P.A. (author), Fokkema, J. (author), Snieder, R. (author)

We compare two approaches for deriving the fact that the Green’s function in an arbitrary inhomogeneous open system can be obtained by cross correlating recordings of the wave field at two positions. One approach is based on physical arguments, exploiting the principle of time-reversal invariance of the acoustic wave equation. The other approach...

journal article 2005

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De uitdaging kent geen grenzen

Fokkema, J.T (author)

public lecture 2005

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Innovatief ontwerpen: Oplossingen voor overmorgen

Fokkema, J.T (author)

public lecture 2004

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We have a question

Fokkema, J.T (author)

public lecture 2003