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2013


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Learning output kernels for multi-task problems

Dinuzzo, F.

Neurocomputing, 118, pages: 119-126, 2013 (article)

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DOI [BibTex]

2013


DOI [BibTex]


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Analytical probabilistic modeling for radiation therapy treatment planning

Bangert, M., Hennig, P., Oelfke, U.

Physics in Medicine and Biology, 58(16):5401-5419, 2013 (article)

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PDF DOI [BibTex]

PDF DOI [BibTex]


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Imaging Findings and Therapy Response Monitoring in Chronic Sclerodermatous Graft-Versus-Host Disease: Preliminary Data of a Simultaneous PET/MRI Approach

Sauter, A., Schmidt, H., Mantlik, F., Kolb, A., Federmann, B., Pfannenberg, C., Reimold, M., Pichler, B., Bethge, W., Horger, M.

Clinical Nuclear Medicine, 38(8):e309-e317, 2013 (article)

Abstract
PURPOSE: Our objective was a multifunctional imaging approach of chronic sclerodermatous graft-versus-host disease (ScGVHD) and its course during therapy using PET/MRI. METHODS: We performed partial-body PET/CT and PET/MRI of the calf in 6 consecutively recruited patients presenting with severe ScGVHD. The patients were treated with different immunosuppressive regimens and supportive therapies. PET/CT scanning started 60.5 +/- 3.3 minutes, PET/MRI imaging 139.5 +/- 16.7 minutes after F-FDG application. MRI acquisition included T1- (precontrast and postcontrast) and T2-weighted sequences. SUVmean, T1 contrast enhancement, and T2 signal intensity from region-of-interest analysis were calculated for different fascial and muscular compartments. In addition, musculoskeletal MRI findings and the modified Rodnan skin score were assessed. All patients underwent imaging follow-up. RESULTS: At baseline PET/MRI, ScGVHD-related musculoskeletal abnormalities consisted of increased signal and/or thickening of involved anatomical structures on T2-weighted and T1 postcontrast images as well as an increased FDG uptake. At follow-up, ScGVHD-related imaging findings decreased (SUVmean n = 4, mean T1 contrast enhancement n = 5, mean T2 signal intensity n = 3) or progressed (SUVmean n = 3, mean T1 contrast enhancement n = 2, mean T2 signal intensity n = 4). Clinically modified Rodnan skin score improved for 5 follow-ups and progressed for 2. SUVmean values correlated between PET/CT and PET/MRI acquisition (r = 0.660, P = 0.014), T1 contrast enhancement, and T2 signal (r = 0.668, P = 0.012), but not between the SUVmean values and the MRI parameters. CONCLUSIONS: PET/MRI as a combined morphological and functional technique seems to assess the inflammatory processes from different points of view and provides therefore in part complementary information

ei

Web [BibTex]

Web [BibTex]


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A Survey on Policy Search for Robotics, Foundations and Trends in Robotics

Deisenroth, M., Neumann, G., Peters, J.

Foundations and Trends in Robotics, 2(1-2):1-142, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Reinforcement Learning in Robotics: A Review

Kober, J., Bagnell, D., Peters, J.

International Journal of Robotics Research, 32(11):1238–1274, 2013 (article)

ei

PDF DOI [BibTex]

PDF DOI [BibTex]


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Multimodal information improves the rapid detection of mental fatigue

Laurent, F., Valderrama, M., Besserve, M., Guillard, M., Lachaux, J., Martinerie, J., Florence, G.

Biomedical Signal Processing and Control, 8(4):400 - 408, 2013 (article)

ei

Web DOI [BibTex]

Web DOI [BibTex]


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Interactive Domain Adaptation for the Classification of Remote Sensing Images using Active Learning

Persello, C.

IEEE Geoscience and Remote Sensing Letters, 10(4):736-740, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Learning to Select and Generalize Striking Movements in Robot Table Tennis

Mülling, K., Kober, J., Kroemer, O., Peters, J.

International Journal of Robotics Research, 32(3):263-279, 2013 (article)

ei

PDF DOI [BibTex]

PDF DOI [BibTex]


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Proceedings of the 10th European Workshop on Reinforcement Learning, Volume 24

Deisenroth, M., Szepesvári, C., Peters, J.

pages: 173, JMLR, European Workshop On Reinforcement Learning, EWRL, 2013 (proceedings)

ei

Web [BibTex]

Web [BibTex]


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HiFiVE: A Hilbert Space Embedding of Fiber Variability Estimates for Uncertainty Modeling and Visualization

Schultz, T., Schlaffke, L., Schölkopf, B., Schmidt-Wilcke, T.

Computer Graphics Forum, 32(3):121-130, (Editors: B Preim, P Rheingans, and H Theisel), Blackwell Publishing, Oxford, UK, Eurographics Conference on Visualization (EuroVis), 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Detection and attribution of large spatiotemporal extreme events in Earth observation data

Zscheischler, J., Mahecha, M., Harmeling, S., Reichstein, M.

Ecological Informatics, 15, pages: 66-73, 2013 (article)

Abstract
Latest climate projections suggest that both frequency and intensity of climate extremes will be substantially modified over the course of the coming decades. As a consequence, we need to understand to what extent and via which pathways climate extremes affect the state and functionality of terrestrial ecosystems and the associated biogeochemical cycles on a global scale. So far the impacts of climate extremes on the terrestrial biosphere were mainly investigated on the basis of case studies, while global assessments are widely lacking. In order to facilitate global analysis of this kind, we present a methodological framework that firstly detects spatiotemporally contiguous extremes in Earth observations, and secondly infers the likely pathway of the preceding climate anomaly. The approach does not require long time series, is computationally fast, and easily applicable to a variety of data sets with different spatial and temporal resolutions. The key element of our analysis strategy is to directly search in the relevant observations for spatiotemporally connected components exceeding a certain percentile threshold. We also put an emphasis on characterization of extreme event distribution, and scrutinize the attribution issue. We exemplify the analysis strategy by exploring the fraction of absorbed photosynthetically active radiation (fAPAR) from 1982 to 2011. Our results suggest that the hot spots of extremes in fAPAR lie in Northeastern Brazil, Southeastern Australia, Kenya and Tanzania. Moreover, we demonstrate that the size distribution of extremes follow a distinct power law. The attribution framework reveals that extremes in fAPAR are primarily driven by phases of water scarcity.

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Web DOI [BibTex]

Web DOI [BibTex]


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Simultaneous PET/MR reveals Brain Function in Activated and Resting State on Metabolic, Hemodynamic and Multiple Temporal Scales

Wehrl, H., Hossain, M., Lankes, K., Liu, C., Bezrukov, I., Martirosian, P., Schick, F., Reischl, G., Pichler, B.

Nature Medicine, 19, pages: 1184–1189, 2013 (article)

Abstract
Combined positron emission tomography (PET) and magnetic resonance imaging (MRI) is a new tool to study functional processes in the brain. Here we study brain function in response to a barrel-field stimulus simultaneously using PET, which traces changes in glucose metabolism on a slow time scale, and functional MRI (fMRI), which assesses fast vascular and oxygenation changes during activation. We found spatial and quantitative discrepancies between the PET and the fMRI activation data. The functional connectivity of the rat brain was assessed by both modalities: the fMRI approach determined a total of nine known neural networks, whereas the PET method identified seven glucose metabolism–related networks. These results demonstrate the feasibility of combined PET-MRI for the simultaneous study of the brain at activation and rest, revealing comprehensive and complementary information to further decode brain function and brain networks.

ei

Web DOI [BibTex]

Web DOI [BibTex]


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Finding Potential Support Vectors in Separable Classification Problems

Varagnolo, D., Del Favero, S., Dinuzzo, F., Schenato, L., Pillonetto, G.

IEEE Transactions on Neural Networks and Learning Systems, 24(11):1799-1813, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Open-Box Spectral Clustering: Applications to Medical Image Analysis

Schultz, T., Kindlmann, G.

IEEE Transactions on Visualization and Computer Graphics, 19(12):2100-2108, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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im3shape: a maximum likelihood galaxy shear measurement code for cosmic gravitational lensing

Zuntz, J., Kacprzak, T., Voigt, L., Hirsch, M., Rowe, B., Bridle, S.

Monthly Notices of the Royal Astronomical Society, 434(2):1604-1618, Oxford University Press, 2013 (article)

ei

DOI [BibTex]

DOI [BibTex]


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Accurate detection of differential RNA processing

Drewe, P., Stegle, O., Hartmann, L., Kahles, A., Bohnert, R., Wachter, A., Borgwardt, K. M., Rätsch, G.

Nucleic Acids Research, 41(10):5189-5198, 2013 (article)

ei

DOI [BibTex]

DOI [BibTex]


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Detecting regulatory gene–environment interactions with unmeasured environmental factors

Fusi, N., Lippert, C., Borgwardt, K. M., Lawrence, N. D., Stegle, O.

Bioinformatics, 29(11):1382-1389, 2013 (article)

ei

DOI [BibTex]

DOI [BibTex]


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Fragmentation of Slow Wave Sleep after Onset of Complete Locked-In State

Soekadar, S. R., Born, J., Birbaumer, N., Bensch, M., Halder, S., Murguialday, A. R., Gharabaghi, A., Nijboer, F., Schölkopf, B., Martens, S.

Journal of Clinical Sleep Medicine, 9(9):951-953, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Structural learning

Braun, D

Scholarpedia, 8(10):12312, October 2013 (article)

Abstract
Structural learning in motor control refers to a metalearning process whereby an agent extracts (abstract) invariants from its sensorimotor stream when experiencing a range of environments that share similar structure. Such invariants can then be exploited for faster generalization and learning-to-learn when experiencing novel, but related task environments.

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DOI [BibTex]

DOI [BibTex]


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The effect of model uncertainty on cooperation in sensorimotor interactions

Grau-Moya, J, Hez, E, Pezzulo, G, Braun, DA

Journal of the Royal Society Interface, 10(87):1-11, October 2013 (article)

Abstract
Decision-makers have been shown to rely on probabilistic models for perception and action. However, these models can be incorrect or partially wrong in which case the decision-maker has to cope with model uncertainty. Model uncertainty has recently also been shown to be an important determinant of sensorimotor behaviour in humans that can lead to risk-sensitive deviations from Bayes optimal behaviour towards worst-case or best-case outcomes. Here, we investigate the effect of model uncertainty on cooperation in sensorimotor interactions similar to the stag-hunt game, where players develop models about the other player and decide between a pay-off-dominant cooperative solution and a risk-dominant, non-cooperative solution. In simulations, we show that players who allow for optimistic deviations from their opponent model are much more likely to converge to cooperative outcomes. We also implemented this agent model in a virtual reality environment, and let human subjects play against a virtual player. In this game, subjects' pay-offs were experienced as forces opposing their movements. During the experiment, we manipulated the risk sensitivity of the computer player and observed human responses. We found not only that humans adaptively changed their level of cooperation depending on the risk sensitivity of the computer player but also that their initial play exhibited characteristic risk-sensitive biases. Our results suggest that model uncertainty is an important determinant of cooperation in two-player sensorimotor interactions.

ei

DOI [BibTex]

DOI [BibTex]


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Thermodynamics as a theory of decision-making with information-processing costs

Ortega, PA, Braun, DA

Proceedings of the Royal Society of London A, 469(2153):1-18, May 2013 (article)

Abstract
Perfectly rational decision-makers maximize expected utility, but crucially ignore the resource costs incurred when determining optimal actions. Here, we propose a thermodynamically inspired formalization of bounded rational decision-making where information processing is modelled as state changes in thermodynamic systems that can be quantified by differences in free energy. By optimizing a free energy, bounded rational decision-makers trade off expected utility gains and information-processing costs measured by the relative entropy. As a result, the bounded rational decision-making problem can be rephrased in terms of well-known variational principles from statistical physics. In the limit when computational costs are ignored, the maximum expected utility principle is recovered. We discuss links to existing decision-making frameworks and applications to human decision-making experiments that are at odds with expected utility theory. Since most of the mathematical machinery can be borrowed from statistical physics, the main contribution is to re-interpret the formalism of thermodynamic free-energy differences in terms of bounded rational decision-making and to discuss its relationship to human decision-making experiments.

ei

DOI [BibTex]

DOI [BibTex]