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151 results (View BibTeX file of all listed publications)

2017

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On the Design of LQR Kernels for Efficient Controller Learning

Marco, A., Hennig, P., Schaal, S., Trimpe, S.

Proceedings of the 56th IEEE Annual Conference on Decision and Control (CDC), pages: 5193-5200, IEEE, IEEE Conference on Decision and Control, December 2017 (conference)

Abstract
Finding optimal feedback controllers for nonlinear dynamic systems from data is hard. Recently, Bayesian optimization (BO) has been proposed as a powerful framework for direct controller tuning from experimental trials. For selecting the next query point and finding the global optimum, BO relies on a probabilistic description of the latent objective function, typically a Gaussian process (GP). As is shown herein, GPs with a common kernel choice can, however, lead to poor learning outcomes on standard quadratic control problems. For a first-order system, we construct two kernels that specifically leverage the structure of the well-known Linear Quadratic Regulator (LQR), yet retain the flexibility of Bayesian nonparametric learning. Simulations of uncertain linear and nonlinear systems demonstrate that the LQR kernels yield superior learning performance.

am ics pn

arXiv PDF On the Design of LQR Kernels for Efficient Controller Learning - CDC presentation DOI Project Page [BibTex]

2017

am ics pn Marco, A., Hennig, P., Schaal, S., Trimpe, S. On the Design of LQR Kernels for Efficient Controller Learning Proceedings of the 56th IEEE Annual Conference on Decision and Control (CDC), pages: 5193-5200, IEEE, IEEE Conference on Decision and Control, December 2017 (conference)

arXiv PDF On the Design of LQR Kernels for Efficient Controller Learning - CDC presentation DOI Project Page [BibTex]

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Probabilistic Line Searches for Stochastic Optimization

Mahsereci, M., Hennig, P.

Journal of Machine Learning Research, 18(119):1-59, November 2017 (article)

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link (url) Project Page [BibTex]

pn Mahsereci, M., Hennig, P. Probabilistic Line Searches for Stochastic Optimization Journal of Machine Learning Research, 18(119):1-59, November 2017 (article)

link (url) Project Page [BibTex]

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Coupling Adaptive Batch Sizes with Learning Rates

Balles, L., Romero, J., Hennig, P.

In Proceedings Conference on Uncertainty in Artificial Intelligence (UAI) 2017, pages: 410-419, (Editors: Gal Elidan and Kristian Kersting), Association for Uncertainty in Artificial Intelligence (AUAI), Conference on Uncertainty in Artificial Intelligence (UAI), August 2017 (inproceedings)

Abstract
Mini-batch stochastic gradient descent and variants thereof have become standard for large-scale empirical risk minimization like the training of neural networks. These methods are usually used with a constant batch size chosen by simple empirical inspection. The batch size significantly influences the behavior of the stochastic optimization algorithm, though, since it determines the variance of the gradient estimates. This variance also changes over the optimization process; when using a constant batch size, stability and convergence is thus often enforced by means of a (manually tuned) decreasing learning rate schedule. We propose a practical method for dynamic batch size adaptation. It estimates the variance of the stochastic gradients and adapts the batch size to decrease the variance proportionally to the value of the objective function, removing the need for the aforementioned learning rate decrease. In contrast to recent related work, our algorithm couples the batch size to the learning rate, directly reflecting the known relationship between the two. On three image classification benchmarks, our batch size adaptation yields faster optimization convergence, while simultaneously simplifying learning rate tuning. A TensorFlow implementation is available.

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Code link (url) Project Page [BibTex]

ps pn Balles, L., Romero, J., Hennig, P. Coupling Adaptive Batch Sizes with Learning Rates In Proceedings Conference on Uncertainty in Artificial Intelligence (UAI) 2017, pages: 410-419, (Editors: Gal Elidan and Kristian Kersting), Association for Uncertainty in Artificial Intelligence (AUAI), Conference on Uncertainty in Artificial Intelligence (UAI), August 2017 (inproceedings)

Code link (url) Project Page [BibTex]

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Dynamic Time-of-Flight

Schober, M., Adam, A., Yair, O., Mazor, S., Nowozin, S.

Proceedings IEEE Conference on Computer Vision and Pattern Recognition (CVPR) 2017, pages: 170-179, IEEE, Piscataway, NJ, USA, IEEE Conference on Computer Vision and Pattern Recognition (CVPR), July 2017 (conference)

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DOI [BibTex]

ei pn Schober, M., Adam, A., Yair, O., Mazor, S., Nowozin, S. Dynamic Time-of-Flight Proceedings IEEE Conference on Computer Vision and Pattern Recognition (CVPR) 2017, pages: 170-179, IEEE, Piscataway, NJ, USA, IEEE Conference on Computer Vision and Pattern Recognition (CVPR), July 2017 (conference)

DOI [BibTex]

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Virtual vs. Real: Trading Off Simulations and Physical Experiments in Reinforcement Learning with Bayesian Optimization

Marco, A., Berkenkamp, F., Hennig, P., Schoellig, A. P., Krause, A., Schaal, S., Trimpe, S.

In Proceedings of the IEEE International Conference on Robotics and Automation (ICRA), pages: 1557-1563, IEEE, Piscataway, NJ, USA, IEEE International Conference on Robotics and Automation (ICRA), May 2017 (inproceedings)

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PDF arXiv ICRA 2017 Spotlight presentation Virtual vs. Real - Video explanation DOI Project Page [BibTex]

am ics pn Marco, A., Berkenkamp, F., Hennig, P., Schoellig, A. P., Krause, A., Schaal, S., Trimpe, S. Virtual vs. Real: Trading Off Simulations and Physical Experiments in Reinforcement Learning with Bayesian Optimization In Proceedings of the IEEE International Conference on Robotics and Automation (ICRA), pages: 1557-1563, IEEE, Piscataway, NJ, USA, IEEE International Conference on Robotics and Automation (ICRA), May 2017 (inproceedings)

PDF arXiv ICRA 2017 Spotlight presentation Virtual vs. Real - Video explanation DOI Project Page [BibTex]

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Fast Bayesian Optimization of Machine Learning Hyperparameters on Large Datasets

Klein, A., Falkner, S., Bartels, S., Hennig, P., Hutter, F.

Proceedings of the 20th International Conference on Artificial Intelligence and Statistics (AISTATS 2017), 54, pages: 528-536, Proceedings of Machine Learning Research, (Editors: Sign, Aarti and Zhu, Jerry), PMLR, April 2017 (conference)

pn

pdf link (url) Project Page [BibTex]

pn Klein, A., Falkner, S., Bartels, S., Hennig, P., Hutter, F. Fast Bayesian Optimization of Machine Learning Hyperparameters on Large Datasets Proceedings of the 20th International Conference on Artificial Intelligence and Statistics (AISTATS 2017), 54, pages: 528-536, Proceedings of Machine Learning Research, (Editors: Sign, Aarti and Zhu, Jerry), PMLR, April 2017 (conference)

pdf link (url) Project Page [BibTex]

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Early Stopping Without a Validation Set

Mahsereci, M., Balles, L., Lassner, C., Hennig, P.

arXiv preprint arXiv:1703.09580, 2017 (article)

Abstract
Early stopping is a widely used technique to prevent poor generalization performance when training an over-expressive model by means of gradient-based optimization. To find a good point to halt the optimizer, a common practice is to split the dataset into a training and a smaller validation set to obtain an ongoing estimate of the generalization performance. In this paper we propose a novel early stopping criterion which is based on fast-to-compute, local statistics of the computed gradients and entirely removes the need for a held-out validation set. Our experiments show that this is a viable approach in the setting of least-squares and logistic regression as well as neural networks.

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link (url) Project Page Project Page [BibTex]

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Krylov Subspace Recycling for Fast Iterative Least-Squares in Machine Learning

Roos, F. D., Hennig, P.

arXiv preprint arXiv:1706.00241, 2017 (article)

Abstract
Solving symmetric positive definite linear problems is a fundamental computational task in machine learning. The exact solution, famously, is cubicly expensive in the size of the matrix. To alleviate this problem, several linear-time approximations, such as spectral and inducing-point methods, have been suggested and are now in wide use. These are low-rank approximations that choose the low-rank space a priori and do not refine it over time. While this allows linear cost in the data-set size, it also causes a finite, uncorrected approximation error. Authors from numerical linear algebra have explored ways to iteratively refine such low-rank approximations, at a cost of a small number of matrix-vector multiplications. This idea is particularly interesting in the many situations in machine learning where one has to solve a sequence of related symmetric positive definite linear problems. From the machine learning perspective, such deflation methods can be interpreted as transfer learning of a low-rank approximation across a time-series of numerical tasks. We study the use of such methods for our field. Our empirical results show that, on regression and classification problems of intermediate size, this approach can interpolate between low computational cost and numerical precision.

pn

link (url) Project Page [BibTex]

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Convergence Analysis of Deterministic Kernel-Based Quadrature Rules in Misspecified Settings

Kanagawa, M., Sriperumbudur, B. K., Fukumizu, K.

Arxiv e-prints, arXiv:1709.00147v1 [math.NA], 2017 (article)

Abstract
This paper presents convergence analysis of kernel-based quadrature rules in misspecified settings, focusing on deterministic quadrature in Sobolev spaces. In particular, we deal with misspecified settings where a test integrand is less smooth than a Sobolev RKHS based on which a quadrature rule is constructed. We provide convergence guarantees based on two different assumptions on a quadrature rule: one on quadrature weights, and the other on design points. More precisely, we show that convergence rates can be derived (i) if the sum of absolute weights remains constant (or does not increase quickly), or (ii) if the minimum distance between distance design points does not decrease very quickly. As a consequence of the latter result, we derive a rate of convergence for Bayesian quadrature in misspecified settings. We reveal a condition on design points to make Bayesian quadrature robust to misspecification, and show that, under this condition, it may adaptively achieve the optimal rate of convergence in the Sobolev space of a lesser order (i.e., of the unknown smoothness of a test integrand), under a slightly stronger regularity condition on the integrand.

pn

arXiv [BibTex]

pn Kanagawa, M., Sriperumbudur, B. K., Fukumizu, K. Convergence Analysis of Deterministic Kernel-Based Quadrature Rules in Misspecified Settings Arxiv e-prints, arXiv:1709.00147v1 [math.NA], 2017 (article)

arXiv [BibTex]

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New Directions for Learning with Kernels and Gaussian Processes (Dagstuhl Seminar 16481)

Gretton, A., Hennig, P., Rasmussen, C., Schölkopf, B.

Dagstuhl Reports, 6(11):142-167, 2017 (book)

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DOI [BibTex]

ei pn Gretton, A., Hennig, P., Rasmussen, C., Schölkopf, B. New Directions for Learning with Kernels and Gaussian Processes (Dagstuhl Seminar 16481) Dagstuhl Reports, 6(11):142-167, 2017 (book)

DOI [BibTex]

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Functionalised metal-organic frameworks: a novel approach to stabilising single metal atoms

Szilágyi, P. Á., Rogers, D. M., Zaiser, I., Callini, E., Turner, S., Borgschulte, A., Züttel, A., Geerlings, H., Hirscher, M., Dam, B.

{Journal of Materials Chemistry A}, 5(30):15559-15566, Royal Society of Chemistry, Cambridge, UK, 2017 (article)

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DOI [BibTex]

mms Szilágyi, P. Á., Rogers, D. M., Zaiser, I., Callini, E., Turner, S., Borgschulte, A., Züttel, A., Geerlings, H., Hirscher, M., Dam, B. Functionalised metal-organic frameworks: a novel approach to stabilising single metal atoms {Journal of Materials Chemistry A}, 5(30):15559-15566, Royal Society of Chemistry, Cambridge, UK, 2017 (article)

DOI [BibTex]

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Exploiting diffusion barrier and chemical affinity of metal-organic frameworks for efficient hydrogen isotope separation

Kim, J. Y., Balderas-Xicohténcatl, R., Zhang, L., Kang, S. G., Hirscher, M., Oh, H., Moon, H. R.

{Journal of the American Chemical Society}, 139(42):15135-15141, American Chemical Society, Washington, DC, 2017 (article)

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DOI [BibTex]

mms Kim, J. Y., Balderas-Xicohténcatl, R., Zhang, L., Kang, S. G., Hirscher, M., Oh, H., Moon, H. R. Exploiting diffusion barrier and chemical affinity of metal-organic frameworks for efficient hydrogen isotope separation {Journal of the American Chemical Society}, 139(42):15135-15141, American Chemical Society, Washington, DC, 2017 (article)

DOI [BibTex]

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Facile fabrication of mesoporous silica micro-jets with multi-functionalities

Vilela, D., Hortelao, A. C., Balderas-Xicohténcatl, R., Hirscher, M., Hahn, K., Ma, X., Sánchez, S.

{Nanoscale}, 9(37):13990-13997, Royal Society of Chemistry, Cambridge, UK, 2017 (article)

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DOI [BibTex]

mms Vilela, D., Hortelao, A. C., Balderas-Xicohténcatl, R., Hirscher, M., Hahn, K., Ma, X., Sánchez, S. Facile fabrication of mesoporous silica micro-jets with multi-functionalities {Nanoscale}, 9(37):13990-13997, Royal Society of Chemistry, Cambridge, UK, 2017 (article)

DOI [BibTex]

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Selective hydrogen isotope separation via breathing transition in MIL-53(Al)

Kim, J. Y., Zhang, L., Balderas-Xicohténcatl, R., Park, J., Hirscher, M., Moon, H. R., Oh, H.

{Journal of the American Chemical Society}, 139(49):17743-17746, American Chemical Society, Washington, DC, 2017 (article)

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DOI [BibTex]

mms Kim, J. Y., Zhang, L., Balderas-Xicohténcatl, R., Park, J., Hirscher, M., Moon, H. R., Oh, H. Selective hydrogen isotope separation via breathing transition in MIL-53(Al) {Journal of the American Chemical Society}, 139(49):17743-17746, American Chemical Society, Washington, DC, 2017 (article)

DOI [BibTex]

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Efficient synthesis for large-scale production and characterization for hydrogen storage of ligand exchanged MOF-74/174/184-M (M\textequalsMg2+, Ni2+)

Oh, H., Maurer, S., Balderas-Xicohténcatl, R., Arnold, L., Magdysyuk, O. V., Schütz, G., Müller, U., Hirscher, M.

{International Journal of Hydrogen Energy}, 42(2):1027-1035, Elsevier, Amsterdam, 2017 (article)

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DOI [BibTex]

mms Oh, H., Maurer, S., Balderas-Xicohténcatl, R., Arnold, L., Magdysyuk, O. V., Schütz, G., Müller, U., Hirscher, M. Efficient synthesis for large-scale production and characterization for hydrogen storage of ligand exchanged MOF-74/174/184-M (M\textequalsMg2+, Ni2+) {International Journal of Hydrogen Energy}, 42(2):1027-1035, Elsevier, Amsterdam, 2017 (article)

DOI [BibTex]

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Efficiency of analytical and sampling-based uncertainty propagation in intensity-modulated proton therapy

Wahl, N., Hennig, P., Wieser, H. P., Bangert, M.

Physics in Medicine & Biology, 62(14):5790-5807, 2017 (article)

Abstract
The sensitivity of intensity-modulated proton therapy (IMPT) treatment plans to uncertainties can be quantified and mitigated with robust/min-max and stochastic/probabilistic treatment analysis and optimization techniques. Those methods usually rely on sparse random, importance, or worst-case sampling. Inevitably, this imposes a trade-off between computational speed and accuracy of the uncertainty propagation. Here, we investigate analytical probabilistic modeling (APM) as an alternative for uncertainty propagation and minimization in IMPT that does not rely on scenario sampling. APM propagates probability distributions over range and setup uncertainties via a Gaussian pencil-beam approximation into moments of the probability distributions over the resulting dose in closed form. It supports arbitrary correlation models and allows for efficient incorporation of fractionation effects regarding random and systematic errors. We evaluate the trade-off between run-time and accuracy of APM uncertainty computations on three patient datasets. Results are compared against reference computations facilitating importance and random sampling. Two approximation techniques to accelerate uncertainty propagation and minimization based on probabilistic treatment plan optimization are presented. Runtimes are measured on CPU and GPU platforms, dosimetric accuracy is quantified in comparison to a sampling-based benchmark (5000 random samples). APM accurately propagates range and setup uncertainties into dose uncertainties at competitive run-times (GPU ##IMG## [http://ej.iop.org/images/0031-9155/62/14/5790/pmbaa6ec5ieqn001.gif] {$\leqslant {5}$} min). The resulting standard deviation (expectation value) of dose show average global ##IMG## [http://ej.iop.org/images/0031-9155/62/14/5790/pmbaa6ec5ieqn002.gif] {$\gamma_{{3}\% / {3}~{\rm mm}}$} pass rates between 94.2% and 99.9% (98.4% and 100.0%). All investigated importance sampling strategies provided less accuracy at higher run-times considering only a single fraction. Considering fractionation, APM uncertainty propagation and treatment plan optimization was proven to be possible at constant time complexity, while run-times of sampling-based computations are linear in the number of fractions. Using sum sampling within APM, uncertainty propagation can only be accelerated at the cost of reduced accuracy in variance calculations. For probabilistic plan optimization, we were able to approximate the necessary pre-computations within seconds, yielding treatment plans of similar quality as gained from exact uncertainty propagation. APM is suited to enhance the trade-off between speed and accuracy in uncertainty propagation and probabilistic treatment plan optimization, especially in the context of fractionation. This brings fully-fledged APM computations within reach of clinical application.

pn

link (url) [BibTex]

pn Wahl, N., Hennig, P., Wieser, H. P., Bangert, M. Efficiency of analytical and sampling-based uncertainty propagation in intensity-modulated proton therapy Physics in Medicine & Biology, 62(14):5790-5807, 2017 (article)

link (url) [BibTex]

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Analytical probabilistic modeling of RBE-weighted dose for ion therapy

Wieser, H., Hennig, P., Wahl, N., Bangert, M.

Physics in Medicine and Biology (PMB), 62(23):8959-8982, 2017 (article)

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link (url) [BibTex]

pn Wieser, H., Hennig, P., Wahl, N., Bangert, M. Analytical probabilistic modeling of RBE-weighted dose for ion therapy Physics in Medicine and Biology (PMB), 62(23):8959-8982, 2017 (article)

link (url) [BibTex]

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Understanding FORC using synthetic micro-structured systems with variable coupling- and coercivefield distributions

Groß, Felix

Universität Stuttgart, Stuttgart, 2017 (mastersthesis)

mms

[BibTex]

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Corrosion-protected hybrid nanoparticles

Jeong, H., Alarcón-Correa, M., Mark, A. G., Son, K., Lee, T., Fischer, P.

{Advanced Science}, 4(12), Wiley-VCH, Weinheim, 2017 (article)

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DOI [BibTex]

mms Jeong, H., Alarcón-Correa, M., Mark, A. G., Son, K., Lee, T., Fischer, P. Corrosion-protected hybrid nanoparticles {Advanced Science}, 4(12), Wiley-VCH, Weinheim, 2017 (article)

DOI [BibTex]

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Investigation of the Dzyaloshinskii-Moriya interaction and room temperature skyrmions in W/CoFeB/MgO thin films and microwires

Jaiswal, S., Litzius, K., Lemesh, I., Büttner, F., Finizio, S., Raabe, J., Weigand, M., Lee, K., Langer, J., Ocker, B., Jakob, G., Beach, G. S. D., Kläui, M.

{Applied Physics Letters}, 111(2), American Institute of Physics, Melville, NY, 2017 (article)

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DOI [BibTex]

mms Jaiswal, S., Litzius, K., Lemesh, I., Büttner, F., Finizio, S., Raabe, J., Weigand, M., Lee, K., Langer, J., Ocker, B., Jakob, G., Beach, G. S. D., Kläui, M. Investigation of the Dzyaloshinskii-Moriya interaction and room temperature skyrmions in W/CoFeB/MgO thin films and microwires {Applied Physics Letters}, 111(2), American Institute of Physics, Melville, NY, 2017 (article)

DOI [BibTex]

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Ultrafast demagnetization after femtosecond laser pulses: Transfer of angular momentum from the electronic system to magnetoelastic spin-phonon modes

Fähnle, M., Tsatsoulis, T., Illg, C., Haag, M., Müller, B. Y., Zhang, L.

{Journal of Superconductivity and Novel Magnetism}, 30(5):1381-1387, Springer Science + Business Media B.V., New York, 2017 (article)

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DOI [BibTex]

mms Fähnle, M., Tsatsoulis, T., Illg, C., Haag, M., Müller, B. Y., Zhang, L. Ultrafast demagnetization after femtosecond laser pulses: Transfer of angular momentum from the electronic system to magnetoelastic spin-phonon modes {Journal of Superconductivity and Novel Magnetism}, 30(5):1381-1387, Springer Science + Business Media B.V., New York, 2017 (article)

DOI [BibTex]

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Magnetic behavior of single chain magnets in metal organic frameworks CPO-27-Co

Son, K., Goering, E., Hirscher, M., Oh, H.

{Journal of Nanoscience and Nanotechnology}, 17(10):7541-7546, American Scientific Publishers, Stevenson Ranch, Calif., 2017 (article)

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DOI [BibTex]

mms Son, K., Goering, E., Hirscher, M., Oh, H. Magnetic behavior of single chain magnets in metal organic frameworks CPO-27-Co {Journal of Nanoscience and Nanotechnology}, 17(10):7541-7546, American Scientific Publishers, Stevenson Ranch, Calif., 2017 (article)

DOI [BibTex]

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Switching by domain-wall automotion in asymmetric ferromagnetic rings

Mawass, M., Richter, K., Bisig, A., Reeve, R. M., Krüger, B., Weigand, M., Stoll, H., Krone, A., Kronast, F., Schütz, G., Kläui, M.

{Physical Review Applied}, 7(4), American Physical Society, College Park, Md. [u.a.], 2017 (article)

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DOI [BibTex]

mms Mawass, M., Richter, K., Bisig, A., Reeve, R. M., Krüger, B., Weigand, M., Stoll, H., Krone, A., Kronast, F., Schütz, G., Kläui, M. Switching by domain-wall automotion in asymmetric ferromagnetic rings {Physical Review Applied}, 7(4), American Physical Society, College Park, Md. [u.a.], 2017 (article)

DOI [BibTex]

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A neutral atom moving in an external magnetic field does not feel a Lorentz force

Fähnle, M.

{American Journal of Modern Physics}, 6(6):153-155, Science Publishing Group, New York, NY, 2017 (article)

mms

DOI [BibTex]

mms Fähnle, M. A neutral atom moving in an external magnetic field does not feel a Lorentz force {American Journal of Modern Physics}, 6(6):153-155, Science Publishing Group, New York, NY, 2017 (article)

DOI [BibTex]

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Adsorption von Wasserstoffmolekülen in nanoporösen Gerüststrukturen

Kotzur, Nadine

Universität Stuttgart, Stuttgart, 2017 (mastersthesis)

mms

[BibTex]

mms Kotzur, Nadine Adsorption von Wasserstoffmolekülen in nanoporösen Gerüststrukturen Universität Stuttgart, Stuttgart, 2017 (mastersthesis)

[BibTex]

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Temperature-dependent first-order reversal curve measurements on unusually hard magnetic low-temperature phase of MnBi

Muralidhar, S., Gräfe, J., Chen, Y., Etter, M., Gregori, G., Ener, S., Sawatzki, S., Hono, K., Gutfleisch, O., Kronmüller, H., Schütz, G., Goering, E. J.

{Physical Review B}, 95(2), American Physical Society, Woodbury, NY, 2017 (article)

mms

DOI Project Page [BibTex]

mms Muralidhar, S., Gräfe, J., Chen, Y., Etter, M., Gregori, G., Ener, S., Sawatzki, S., Hono, K., Gutfleisch, O., Kronmüller, H., Schütz, G., Goering, E. J. Temperature-dependent first-order reversal curve measurements on unusually hard magnetic low-temperature phase of MnBi {Physical Review B}, 95(2), American Physical Society, Woodbury, NY, 2017 (article)

DOI Project Page [BibTex]

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Smooth and rapid microwave synthesis of MIL-53(Fe) including superparamagnetic \textlessgamma\textgreater-Fe2O3 nanoparticles

Wengert, S., Albrecht, J., Ruoß, S., Stahl, C., Schütz, G., Schäfer, R.

{Journal of Magnetism and Magnetic Materials}, 444, pages: 168-172, NH, Elsevier, Amsterdam, 2017 (article)

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DOI [BibTex]

mms Wengert, S., Albrecht, J., Ruoß, S., Stahl, C., Schütz, G., Schäfer, R. Smooth and rapid microwave synthesis of MIL-53(Fe) including superparamagnetic \textlessgamma\textgreater-Fe2O3 nanoparticles {Journal of Magnetism and Magnetic Materials}, 444, pages: 168-172, NH, Elsevier, Amsterdam, 2017 (article)

DOI [BibTex]

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Characterization and differentiation of rock varnish types from different environments by microanalytical techniques

Macholdt, D. S., Jochum, K. P., Pöhlker, C., Arangio, A., Förster, J., Stoll, B., Weis, U., Weber, B., Müller, M., Kappl, M., Shiraiwa, M., Kilcoyne, A. L. D., Weigand, M., Scholz, D., Haug, G. H., Al-Amri, A., Andreae, M. O.

{Chemical Geology}, 459, pages: 91-118, Elsevier, Amsterdam, 2017 (article)

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DOI [BibTex]

mms Macholdt, D. S., Jochum, K. P., Pöhlker, C., Arangio, A., Förster, J., Stoll, B., Weis, U., Weber, B., Müller, M., Kappl, M., Shiraiwa, M., Kilcoyne, A. L. D., Weigand, M., Scholz, D., Haug, G. H., Al-Amri, A., Andreae, M. O. Characterization and differentiation of rock varnish types from different environments by microanalytical techniques {Chemical Geology}, 459, pages: 91-118, Elsevier, Amsterdam, 2017 (article)

DOI [BibTex]

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Skyrmion Hall effect revealed by direct time-resolved X-ray microscopy

Litzius, K., Lemesh, I., Krüger, B., Bassirian, P., Caretta, L., Richter, K., Büttner, F., Sato, K., Tretiakov, O. A., Förster, J., Reeve, R. M., Weigand, M., Bykova, I., Stoll, H., Schütz, G., Beach, G. S. D., Kläui, M.

{Nature Physics}, 13(2):170-175, Nature Pub. Group, London, 2017 (article)

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DOI [BibTex]

mms Litzius, K., Lemesh, I., Krüger, B., Bassirian, P., Caretta, L., Richter, K., Büttner, F., Sato, K., Tretiakov, O. A., Förster, J., Reeve, R. M., Weigand, M., Bykova, I., Stoll, H., Schütz, G., Beach, G. S. D., Kläui, M. Skyrmion Hall effect revealed by direct time-resolved X-ray microscopy {Nature Physics}, 13(2):170-175, Nature Pub. Group, London, 2017 (article)

DOI [BibTex]

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Comment on magnonic black holes

Fähnle, M., Schütz, G.

{Journal of Magnetism and Magnetic Materials}, 444, pages: 146-146, NH, Elsevier, Amsterdam, 2017 (article)

mms

DOI [BibTex]

mms Fähnle, M., Schütz, G. Comment on magnonic black holes {Journal of Magnetism and Magnetic Materials}, 444, pages: 146-146, NH, Elsevier, Amsterdam, 2017 (article)

DOI [BibTex]

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Cr-Substitution in Ba2In2O5 \mbox⋅ (H2O)x (x \textequals 0.16, 0.74)

Yoon, S., Son, K., Hagemann, H., Widenmeyer, M., Weidenkaff, A.

{Solid State Sciences}, 73, pages: 1-6, Elsevier Masson SAS, Paris, 2017 (article)

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DOI [BibTex]

mms Yoon, S., Son, K., Hagemann, H., Widenmeyer, M., Weidenkaff, A. Cr-Substitution in Ba2In2O5 \mbox⋅ (H2O)x (x \textequals 0.16, 0.74) {Solid State Sciences}, 73, pages: 1-6, Elsevier Masson SAS, Paris, 2017 (article)

DOI [BibTex]

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Comment on half-integer quantum numbers for the total angular momentum of photons in light beams with finite lateral extensions

Fähnle, M.

{American Journal of Modern Physics}, 6(5):88-90, Science Publishing Group, New York, NY, 2017 (article)

mms

DOI [BibTex]

mms Fähnle, M. Comment on half-integer quantum numbers for the total angular momentum of photons in light beams with finite lateral extensions {American Journal of Modern Physics}, 6(5):88-90, Science Publishing Group, New York, NY, 2017 (article)

DOI [BibTex]

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Advanced magneto-optical Kerr effect measurements of superconductors at low temperatures

Stahl, C., Gräfe, J., Ruoß, S., Zahn, P., Bayer, J., Simmendinger, J., Schütz, G., Albrecht, J.

{AIP Advances}, 7(10), 2017 (article)

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DOI [BibTex]

mms Stahl, C., Gräfe, J., Ruoß, S., Zahn, P., Bayer, J., Simmendinger, J., Schütz, G., Albrecht, J. Advanced magneto-optical Kerr effect measurements of superconductors at low temperatures {AIP Advances}, 7(10), 2017 (article)

DOI [BibTex]

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Unifying ultrafast demagnetization and intrinsic Gilbert damping in Co/Ni bilayers with electronic relaxation near the Fermi surface

Zhang, W., He, W., Zhang, X.-Q., Cheng, Z.-H., Teng, J., Fähnle, M.

{Physical Review B}, 96(22), American Physical Society, Woodbury, NY, 2017 (article)

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DOI [BibTex]

mms Zhang, W., He, W., Zhang, X.-Q., Cheng, Z.-H., Teng, J., Fähnle, M. Unifying ultrafast demagnetization and intrinsic Gilbert damping in Co/Ni bilayers with electronic relaxation near the Fermi surface {Physical Review B}, 96(22), American Physical Society, Woodbury, NY, 2017 (article)

DOI [BibTex]

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Influence of the skin barrier on the penetration of topically-applied dexamethasone probed by soft X-ray spectromicroscopy

Yamamoto, K., Klossek, A., Flesch, R., Rancan, F., Weigand, M., Bykova, I., Bechtel, M., Ahlberg, S., Vogt, A., Blume-Peytavi, U., Schrade, P., Bachmann, S., Hedtrich, S., Schäfer-Korting, M., Rühl, E.

{European Journal of Pharmaceutics and Biopharmaceutics}, 118, pages: 30-37, Elsevier, Amsterdam, 2017 (article)

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DOI [BibTex]

mms Yamamoto, K., Klossek, A., Flesch, R., Rancan, F., Weigand, M., Bykova, I., Bechtel, M., Ahlberg, S., Vogt, A., Blume-Peytavi, U., Schrade, P., Bachmann, S., Hedtrich, S., Schäfer-Korting, M., Rühl, E. Influence of the skin barrier on the penetration of topically-applied dexamethasone probed by soft X-ray spectromicroscopy {European Journal of Pharmaceutics and Biopharmaceutics}, 118, pages: 30-37, Elsevier, Amsterdam, 2017 (article)

DOI [BibTex]

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Capture of heavy hydrogen isotopes in a metal-organic framework with active Cu(I) sites

Weinrauch, I., Savchenko, I., Denysenko, D., Souliou, S. M., Kim, H., Le Tacon, M., Daemen, L. L., Cheng, Y., Mavrandonakis, A., Ramirez-Cuesta, A. J., Volkmer, D., Schütz, G., Hirscher, M., Heine, T.

{Nature Communications}, 8, Nature Publishing Group, London, 2017 (article)

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DOI [BibTex]

mms Weinrauch, I., Savchenko, I., Denysenko, D., Souliou, S. M., Kim, H., Le Tacon, M., Daemen, L. L., Cheng, Y., Mavrandonakis, A., Ramirez-Cuesta, A. J., Volkmer, D., Schütz, G., Hirscher, M., Heine, T. Capture of heavy hydrogen isotopes in a metal-organic framework with active Cu(I) sites {Nature Communications}, 8, Nature Publishing Group, London, 2017 (article)

DOI [BibTex]

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Multiscale simulations of topological transformations in magnetic-skyrmion spin structures

De Lucia, A., Litzius, K., Krüger, B., Tretiakov, O. A., Kläui, M.

{Physical Review B}, 96(2), American Physical Society, Woodbury, NY, 2017 (article)

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DOI [BibTex]

mms De Lucia, A., Litzius, K., Krüger, B., Tretiakov, O. A., Kläui, M. Multiscale simulations of topological transformations in magnetic-skyrmion spin structures {Physical Review B}, 96(2), American Physical Society, Woodbury, NY, 2017 (article)

DOI [BibTex]

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Unexpectedly marginal effect of electronic correlations on ultrafast demagnetization after femtosecond laser-pulse excitation

Weng, W., Huang, Haonan, Briones Paz, J. Z., Teeny, N., Müller, B. Y., Haag, M., Kuhn, T., Fähnle, M.

{Physical Review B}, 95(22), American Physical Society, Woodbury, NY, 2017 (article)

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DOI [BibTex]

mms Weng, W., Huang, Haonan, Briones Paz, J. Z., Teeny, N., Müller, B. Y., Haag, M., Kuhn, T., Fähnle, M. Unexpectedly marginal effect of electronic correlations on ultrafast demagnetization after femtosecond laser-pulse excitation {Physical Review B}, 95(22), American Physical Society, Woodbury, NY, 2017 (article)

DOI [BibTex]

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Black manganese-rich crusts on a Gothic cathedral

Macholdt, D. S., Herrmann, S., Jochum, K. P., Kilcoyne, A. L. D., Laubscher, T., Pfisterer, H. K., Pöhlker, C., Schwager, B., Weber, B., Weigand, M., Domke, K. F., Andreae, M. O.

{Atmospheric Environment}, 171, pages: 205-220, Elsevier, Amsterdam [u.a.], 2017 (article)

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DOI [BibTex]

mms Macholdt, D. S., Herrmann, S., Jochum, K. P., Kilcoyne, A. L. D., Laubscher, T., Pfisterer, H. K., Pöhlker, C., Schwager, B., Weber, B., Weigand, M., Domke, K. F., Andreae, M. O. Black manganese-rich crusts on a Gothic cathedral {Atmospheric Environment}, 171, pages: 205-220, Elsevier, Amsterdam [u.a.], 2017 (article)

DOI [BibTex]

2010

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Using an Infinite Von Mises-Fisher Mixture Model to Cluster Treatment Beam Directions in External Radiation Therapy

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

In pages: 746-751 , (Editors: Draghici, S. , T.M. Khoshgoftaar, V. Palade, W. Pedrycz, M.A. Wani, X. Zhu), IEEE, Piscataway, NJ, USA, Ninth International Conference on Machine Learning and Applications (ICMLA), December 2010 (inproceedings)

Abstract
We present a method for fully automated selection of treatment beam ensembles for external radiation therapy. We reformulate the beam angle selection problem as a clustering problem of locally ideal beam orientations distributed on the unit sphere. For this purpose we construct an infinite mixture of von Mises-Fisher distributions, which is suited in general for density estimation from data on the D-dimensional sphere. Using a nonparametric Dirichlet process prior, our model infers probability distributions over both the number of clusters and their parameter values. We describe an efficient Markov chain Monte Carlo inference algorithm for posterior inference from experimental data in this model. The performance of the suggested beam angle selection framework is illustrated for one intra-cranial, pancreas, and prostate case each. The infinite von Mises-Fisher mixture model (iMFMM) creates between 18 and 32 clusters, depending on the patient anatomy. This suggests to use the iMFMM directly for beam ensemble selection in robotic radio surgery, or to generate low-dimensional input for both subsequent optimization of trajectories for arc therapy and beam ensemble selection for conventional radiation therapy.

ei pn

Web DOI [BibTex]

2010

ei pn Bangert, M., Hennig, P., Oelfke, U. Using an Infinite Von Mises-Fisher Mixture Model to Cluster Treatment Beam Directions in External Radiation Therapy In pages: 746-751 , (Editors: Draghici, S. , T.M. Khoshgoftaar, V. Palade, W. Pedrycz, M.A. Wani, X. Zhu), IEEE, Piscataway, NJ, USA, Ninth International Conference on Machine Learning and Applications (ICMLA), December 2010 (inproceedings)

Web DOI [BibTex]

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Coherent Inference on Optimal Play in Game Trees

Hennig, P., Stern, D., Graepel, T.

In JMLR Workshop and Conference Proceedings Volume 9: AISTATS 2010, pages: 326-333, (Editors: Teh, Y.W. , M. Titterington ), JMLR, Cambridge, MA, USA, Thirteenth International Conference on Artificial Intelligence and Statistics, May 2010 (inproceedings)

Abstract
Round-based games are an instance of discrete planning problems. Some of the best contemporary game tree search algorithms use random roll-outs as data. Relying on a good policy, they learn on-policy values by propagating information upwards in the tree, but not between sibling nodes. Here, we present a generative model and a corresponding approximate message passing scheme for inference on the optimal, off-policy value of nodes in smooth AND/OR trees, given random roll-outs. The crucial insight is that the distribution of values in game trees is not completely arbitrary. We define a generative model of the on-policy values using a latent score for each state, representing the value under the random roll-out policy. Inference on the values under the optimal policy separates into an inductive, pre-data step and a deductive, post-data part. Both can be solved approximately with Expectation Propagation, allowing off-policy value inference for any node in the (exponentially big) tree in linear time.

ei pn

PDF Web [BibTex]

ei pn Hennig, P., Stern, D., Graepel, T. Coherent Inference on Optimal Play in Game Trees In JMLR Workshop and Conference Proceedings Volume 9: AISTATS 2010, pages: 326-333, (Editors: Teh, Y.W. , M. Titterington ), JMLR, Cambridge, MA, USA, Thirteenth International Conference on Artificial Intelligence and Statistics, May 2010 (inproceedings)

PDF Web [BibTex]

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Dzyaloshinskii-Moriya interactions in systems with fabrication induced strain gradients: ab-initio study

Beck, P., Fähnle, M

{Journal of Magnetism and Magnetic Materials}, 322, pages: 3701-3703, 2010 (article)

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DOI [BibTex]

mms Beck, P., Fähnle, M Dzyaloshinskii-Moriya interactions in systems with fabrication induced strain gradients: ab-initio study {Journal of Magnetism and Magnetic Materials}, 322, pages: 3701-3703, 2010 (article)

DOI [BibTex]

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On the nature of displacement bursts during nanoindentation of ultrathin Ni films on sapphire

Rabkin, E., Deuschle, J. K., Baretzky, B.

{Acta Materialia}, 58, pages: 1589-1598, 2010 (article)

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DOI [BibTex]

mms Rabkin, E., Deuschle, J. K., Baretzky, B. On the nature of displacement bursts during nanoindentation of ultrathin Ni films on sapphire {Acta Materialia}, 58, pages: 1589-1598, 2010 (article)

DOI [BibTex]