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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
document
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.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. (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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Seo, M.A. (author), Adam, A.J.L. (author), Kang, J.H. (author), Lee, J.W. (author), Ahn, K.J. (author), Park, Q.H. (author), Planken, P.C.M. (author), Kim, D.S. (author)
We performed terahertz near-field experiments on single rectangular holes with various lengths grown on an electro-optic crystal substrate with ?/100 resolution. We find that the near-field amplitude becomes proportionally larger as the rectangle becomes narrower, strongly suggesting that a constant energy passes through even for a very narrow...
journal article 2008
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Deibel, J.A. (author), Berndsen, N. (author), Wang, K. (author), Mittleman, D.M. (author), Van der Valk, N.C.J. (author), Planken, P.C.M. (author)
We report on the emission patterns from THz plasmons propagating towards the end of cylindrical metal waveguides. Such waveguides exhibit low loss and dispersion, but little is known about the dynamics of the terahertz radiation at the end of the waveguide, specifically in the near- and intermediate-field. Our experimental results and numerical...
journal article 2006
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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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Ramanandan, G.K.P. (author), Ramakrishnan, G. (author), Planken, P.C.M. (author)
Terahertz (THz) transmission spectroscopy is used to measure the oxidation kinetics of copper thin films evaporated on silicon substrates. The transmission of broadband THz pulses from 1 to 7 THz through the copper film is measured while it gets oxidized at an elevated temperature in ambient air. The change in the transmitted THz electric field...
journal article 2012
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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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Knab, J.R. (author), Adam, A.J.L. (author), Nagel, M. (author), Shaner, E. (author), Seo, M.A. (author), Kim, D.S. (author), Planken, P.C.M. (author)
We present measurements of the complete terahertz (THz) electric near-field distribution, Ex, Ey and Ez, in both the time- and frequency-domains, for subwavelength apertures and subsections of subwavelength aperture arrays. Measuring the individual components of the THz near-field with subwavelength spatial resolution, as they emerge from these...
journal article 2009
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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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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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Ramanandan, G.K.P. (author), Adam, A.J.L. (author), Ramakrishnan, G. (author), Petrik, P. (author), Hendrikx, R. (author), Planken, P.C.M. (author)
We show that the interface between gold and thermally formed cuprous oxide, which emits terahertz radiation when illuminated with ultrafast femtosecond lasers, is in fact an AuCu/Cu2O interface due to the formation of the thermal diffusion alloy AuCu. The alloy enables the formation of a Schottky-barrier-like electric field near the interface...
journal article 2014
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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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