630 research outputs found
Perturbing open cavities: Anomalous resonance frequency shifts in a hybrid cavity-nanoantenna system
The influence of a small perturbation on a cavity mode plays an important
role in fields like optical sensing, cavity quantum electrodynamics and cavity
optomechanics. Typically, the resulting cavity frequency shift directly relates
to the polarizability of the perturbation. Here we demonstrate that particles
perturbing a radiating cavity can induce strong frequency shifts that are
opposite to, and even exceed, the effects based on the particles'
polarizability. A full electrodynamic theory reveals that these anomalous
results rely on a non-trivial phase relation between cavity and nanoparticle
radiation, allowing back-action via the radiation continuum. In addition, an
intuitive model based on coupled mode theory is presented that relates the
phenomenon to retardation. Because of the ubiquity of dissipation, we expect
these findings to benefit the understanding and engineering of a wide class of
systems.Comment: 15 pages, 12 figure
Disorder-induced melting of the charge order in thin films of Pr0.5Ca0.5MnO3
We have studied the magnetic-field-induced melting of the charge order in
thin films of Pr0.5Ca0.5MnO3 (PCMO) films on SrTiO3 (STO) by X-ray diffraction,
magnetization and transport measurement. At small thickness (25 nm) the films
are under tensile strain and the low-temperature melting fields are of the
order of 20 T or more, comparable to the bulk value. With increasing film
thickness the strain relaxes, which leads to a strong decrease of the melting
fields. For a film of 150 nm, with in-plane and out-of-plane lattice parameters
closer to the bulk value, the melting field has reduced to 4 T at 50 K, with a
strong increase in the hysteretic behavior and also an increasing fraction of
ferromagnetic material. Strain relaxation by growth on a template of
YBa2Cu3O(7-delta) or by post-annealing yields similar results with an even
stronger reduction of the melting field. Apparently, strained films behave
bulk-like. Relaxation leads to increasing suppression of the CO state,
presumably due to atomic scale disorder produced by the relaxation process.Comment: 7 pages, 4 fig
Responding to the Lehman wave : sales forecasting and supply management during the credit crisis
In this paper we analyze the strong dip in the manufacturing industry seen at the end of 2008 and provide evidence from various sources that it was caused by cumulative de-stocking, triggered by the bankruptcy of Lehman Brothers. This de-stocking created a giant dampened wave, the so-called Lehman wave. We model the Lehman Wave using system dynamics and validate the model using data from a number of business units and market segments of Royal DSM. We show that the model gives a very good prediction of sales development during the credit crisis. We provide insights into how these results can be used to improve sales forecasting and supply chain management during times of severe crises. We also show that the effects of the current financial crisis are far from over and suggest that our methods be used to predict sales during the year 2010
Non-Fermi-liquid behavior in Ce(RuFe)Ge: cause and effect
We present inelastic neutron scattering measurements on the intermetallic
compounds Ce(RuFe)Ge (=0.65, 0.76 and 0.87). These
compounds represent samples in a magnetically ordered phase, at a quantum
critical point and in the heavy-fermion phase, respectively. We show that at
high temperatures the three compositions have the identical response of a local
moment system. However, at low temperatures the spin fluctuations in the
critical composition are given by non-Fermi-liquid dynamics, while the spin
fluctuations in the heavy fermion system show a simple exponential decay in
time. In both compositions, the lifetime of the fluctuations is determined
solely by the distance to the quantum critical point. We discuss the
implications of these observations regarding the possible origins of
non-Fermi-liquid behavior in this system.Comment: 4 figures, submitted to PR
Local-To-Global Hypotheses for Robust Robot Localization
Many robust state-of-the-art localization methods rely on pose-space sample sets that are evaluated against individual sensor measurements. While these methods can work effectively, they often provide limited mechanisms to control the amount of hypotheses based on their similarity. Furthermore, they do not explicitly use associations to create or remove these hypotheses. We propose a global localization strategy that allows a mobile robot to localize using explicit symbolic associations with annotated geometric features. The feature measurements are first combined locally to form a consistent local feature map that is accurate in the vicinity of the robot. Based on this local map, an association tree is maintained that pairs local map features with global map features. The leaves of the tree represent distinct hypotheses on the data associations that allow for globally unmapped features appearing in the local map. We propose a registration step to check if an association hypothesis is supported. Our implementation considers a robot equipped with a 2D LiDAR and we compare the proposed method to a particle filter. We show that maintaining a smaller set of data association hypotheses results in better performance and explainability of the robot’s assumptions, as well as allowing more control over hypothesis bookkeeping. We provide experimental evaluations with a physical robot in a real environment using an annotated geometric building model that contains only the static part of the indoor scene. The result shows that our method outperforms a particle filter implementation in most cases by using fewer hypotheses with more descriptive power.</p
A survey of opponent modeling techniques in automated negotiation
A negotiation between agents is typically an incomplete information game, where the agents initially do not know their opponent’s preferences or strategy. This poses a challenge, as efficient and effective negotiation requires the bidding agent to take the other’s wishes and future behavior into account when deciding on a proposal. Therefore, in order to reach better and earlier agreements, an agent can apply learning techniques to construct a model of the opponent. There is a mature body of research in negotiation that focuses on modeling the opponent, but there exists no recent survey of commonly used opponent modeling techniques. This work aims to advance and integrate knowledge of the field by providing a comprehensive survey of currently existing opponent models in a bilateral negotiation setting. We discuss all possible ways opponent modeling has been used to benefit agents so far, and we introduce a taxonomy of currently existing opponent models based on their underlying learning techniques. We also present techniques to measure the success of opponent models and provide guidelines for deciding on the appropriate performance measures for every opponent model type in our taxonomy
A framework for branched storytelling and matchmaking in multiplayer games
Video games often either have good single player campaign modes or good multi-player campaign-less modes. This paper presents a framework aimed at the full game development pipeline, from designers to programmers, to aid in creating multiplayer campaigns by providing components that help singleplayer story modes to be used in multiplayer interaction settings. We also propose a custom matchmaking system capable of matching players so as to intertwine their individual stories. The proposed framework has been validated in a case study. A set of experimental results show that the framework is capable of producing valuable story crossings and proper matchmaking.info:eu-repo/semantics/acceptedVersio
Kinrooi, Molenweg verkaveling Meytersveld
Dit rapport werd ingediend bij het agentschap samen met een aantal afzonderlijke digitale bijlagen. Een aantal van deze bijlagen zijn niet inbegrepen in dit pdf document en zijn niet online beschikbaar. Sommige bijlagen (grondplannen, fotos, spoorbeschrijvingen, enz.) kunnen van belang zijn voor een betere lezing en interpretatie van dit rapport. Indien u deze bijlagen wenst te raadplegen kan u daarvoor contact opnemen met: [email protected]
Proximity effects in the superconductor / heavy fermion bilayer system Nb / CeCu_6
We have investigated the proximity effect between a superconductor (Nb) and a
'Heavy Fermion' system (CeCu_6) by measuring critical temperatures and
parallel critical fields H_{c2}^{\parallel}(T) of Nb films with varying
thickness deposited on 75 nm thick films of CeCu_6, and comparing the results
with the behavior of similar films deposited on the normal metal Cu. For Nb on
CeCu_6 we find a strong decrease of T_c with decreasing Nb thickness and a
finite critical thickness of the order of 10 nm. Also, dimensional crossovers
in H_{c2}^{\parallel}(T) are completely absent, in strong contrast with Nb/Cu.
Analysis of the data by a proximity effect model based on the Takahashi-Tachiki
theory shows that the data can be explained by taking into account both the
high effective mass (or low electronic diffusion constant), {\it and} the large
density of states at the Fermi energy which characterize the Heavy Fermion
metal.Comment: 7 pages, 2 figure. Manuscript has been submitted to a refereed
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