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Jalilzadeh, B. (author), Planken, L. (author), De Weerdt, M.M. (author)
We consider online mechanism design without money, where agents are allowed to trade items with other agents, in an attempt to improve their own allocation. In an off-line context, this problem is known as the House Allocation Problem (HAP). We extend HAP to an online problem and call it the Online House Allocation Problem (OHAP). In OHAP,...
book chapter 2010
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Planken, L.R. (author), De Weerdt, M.M. (author), Witteveen, C. (author)
When agents need to interact in order to solve some (possibly common) problem, resolving potential conflicts beforehand is often preferred to coordination during execution. Agents may lose some flexibility, but their course of action will be more predictable and often also more efficient, obtaining a socially optimal outcome instead of a local...
conference paper 2010
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Planken, L.R. (author), De Weerdt, M.M. (author), Yorke-Smith, N. (author)
Efficient management and propagation of temporal constraints is important for temporal planning as well as for scheduling. During plan development, new events and temporal constraints are added and existing constraints may be tightened; the consistency of the whole temporal network is frequently checked; and results of constraint propagation...
conference paper 2010
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Planken, L. (author), De Weerdt, M.M. (author), Van der Krogt, R.P.J. (author)
The Simple Temporal Problem (STP) is a sub-problem of almost any planning or scheduling problem involving time constraints. An existing efficient method to solve the STP, called ?STP, is based on partial path consistency and starts from a chordal constraint graph. In this paper, we analyse this algorithm and show that there exist instances for...
conference paper 2008
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Kihm, H.W. (author), Lee, K.G. (author), Seo, M.A. (author), Ahn, K.J. (author), Adam, A.J.L. (author), Kang, J.H. (author), Park, Q.H. (author), Planken, P.C.M. (author), Kim, D.S. (author)
We study the dielectric constant dependent diffraction phenomena of single slit apertures, both theoretically and experimentally. We experimentally simulate perfect metal and real metal cases by investigating subwavelength diffraction by a single slit, both in nano-optical and in terahertz regimes, keeping the slit-width/wavelength ratio...
conference paper 2008
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Ten Thije, O. (author), Planken, L.R. (author), De Weerdt, M.M. (author)
Efficient management of temporal constraints is important for temporal planning. During plan development, many solvers employ a heuristic-driven backtracking approach, over the course of which they maintain a so-called Simple Temporal Network (STN) of events and constraints. This paper presents the Vertex-IPPC algorithm, which efficiently...
conference paper 2011
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Planken, L.R. (author), De Weerdt, M.M. (author), Van der Krogt, R. (author)
conference paper 2011
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Planken, L.R. (author)
This dissertation describes research into new methods for automated temporal reasoning. For this purpose, several frameworks are available in literature. Chapter 1 presents a concise literature survey that provides a new overview of their interrelation. In the remainder of the dissertation, the focus is on quantitative frameworks, i.e. temporal...
doctoral thesis 2013
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Kajikawa, K. (author), Nagai, Y. (author), Uchiho, Y. (author), Ramakrishnan, G. (author), Kumar, N. (author), Ramanandan, G.K.P. (author), Planken, P.C.M. (author)
Electromagnetic wave emission based on optical rectification at terahertz (THz) wavelengths was observed from surface-immobilized gold nanospheres (SIGNs) above a gold surface. Although the excitation wavelength is off-resonant with the localized surface plasmons, the THz emission field was observed to be approximately 4.8 times greater than...
journal article 2012
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Ramakrishnan, G. (author), Planken, P.C.M. (author)
Emission of pulses of electromagnetic radiation in the terahertz range is observed when ultrathin gold films on glass are illuminated with femtosecond near-IR laser pulses. A distinct maximum is observed in the emitted terahertz amplitude from films of average thickness just above the percolation threshold. Our measurements suggest that the...
journal article 2011
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Vuong, L.T. (author), Adam, A.J.L. (author), Brok, J.M. (author), Planken, P.C.M. (author), Urbach, H.P. (author)
Circularly polarized electric fields incident on subwavelength apertures produce near-field phase singularities with phase vorticity ±1 depending on the polarization handedness. These near-field phase singularities combine with those associated with orbital angular momentum and result in polarization-dependent transmission. We produce arbitrary...
journal article 2010
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Adam, A.J.L. (author), Brok, J.M. (author), Seo, M.A. (author), Ahn, K.J. (author), Kim, D.S. (author), Kang, J.H. (author), Park, Q.H. (author), Nagel, M. (author), Planken, P.C.M. (author)
An erratum is presented to correct an error in the discussion section of [Opt. Express. 16, 7407-7417 (2008)] and to add a relevant reference on earlier work.
journal article 2008
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Knab, J.R. (author), Adam, A.J.L. (author), Shaner, E. (author), Starmans, H.J.A.J. (author), Planken, P.C.M. (author)
We have measured terahertz near-field spectra of cesium iodide crystals as small as ?10 ?m in diameter, which were deposited on single, sub-wavelength-sized apertures created in thin gold films on a substrate. The advantage of using small apertures for terahertz microspectroscopy is that only terahertz light that has interacted with the cesium...
journal article 2013
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Ramakrishnan, G. (author), Ramanandan, G.K.P. (author), Adam, A.J.L. (author), Xu, M. (author), Kumar, N. (author), Hendrikx, R.W.A. (author), Planken, P.C.M. (author)
We report on the surprisingly strong, broadband emission of coherent terahertz pulses from ultrathin layers of semiconductors such as amorphous silicon, germanium and polycrystalline cuprous oxide deposited on gold, upon illumination with femtosecond laser pulses. The strength of the emission is surprising because the materials are considered to...
journal article 2013
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Van der Valk, N.C.J. (author), Planken, P.C.M. (author), Buijserd, A.N. (author), Bakker, H.J. (author)
We present measurements on terahertz generation by optical rectification, in which both the thickness of the generation crystal and the wavelength of the generating optical pulse are varied. The difference between the group velocity at optical frequencies and the phase velocity at terahertz frequencies affects the time trace and spectrum of the...
journal article 2005
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Ramakrishnan, G. (author), Chakkittakandy, R. (author), Planken, P.C.M. (author)
Generation of subpicosecond terahertz pulses is observed when graphite surfaces are illuminated with femtosecond near-infrared laser pulses. The nonlinear optical generation of THz pulses from graphite is unexpected since, in principle, the material possesses a centre of inversion symmetry. Experiments with highly oriented pyrolytic graphite...
journal article 2009
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Pellemans, H.P.M. (author), Planken, P.C.M. (author)
journal article 1998
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Van der Valk, N.C.J. (author), Van der Marel, W.A.M. (author), Planken, P.C.M. (author)
We present a new method to measure the polarization state of a terahertz pulse by using a modified electrooptic sampling setup. To illustrate the power of this method, we show two examples in which the knowledge of the polarization of the terahertz pulse is essential for interpreting the results: spectroscopy measurements on polystyrene foam and...
journal article 2005
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Adam, A.J.L. (author), Planken, P.C.M. (author), Meloni, S. (author), Dik, J. (author)
We show terahertz reflection images of hidden paint layers in a painting on canvas and compare the results with X-ray Radiography and Infrared Reflectography. Our terahertz measurements show strong reflections from both the canvas/paint interface and from the raw umber/lead white interface, indicating sufficient refractive-index contrast. Our...
journal article 2009
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Van der Valk, N.C.J. (author), Planken, P.C.M. (author)
The authors present measurements and calculations on the effect of thin dielectric coatings on the propagation of terahertz pulses along the surface of metal wires. Our measurements show that propagation over only a few centimeters of wire having a thin dielectric coating, strongly distorts the terahertz pulse, which results in a several tens of...
journal article 2005
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