@inbook{19561, author = {{Sellmann, Meinolf and Tierney, Kevin}}, booktitle = {{Lecture Notes in Computer Science}}, isbn = {{9783030535513}}, issn = {{0302-9743}}, keywords = {{pc2-ressources}}, title = {{{Hyper-parameterized Dialectic Search for Non-linear Box-Constrained Optimization with Heterogenous Variable Types}}}, doi = {{10.1007/978-3-030-53552-0_12}}, year = {{2020}}, } @article{19562, author = {{Kuhlemann, Stefan and Tierney, Kevin}}, issn = {{1381-1231}}, journal = {{Journal of Heuristics}}, keywords = {{pc2-ressources}}, title = {{{A genetic algorithm for finding realistic sea routes considering the weather}}}, doi = {{10.1007/s10732-020-09449-7}}, year = {{2020}}, } @article{19679, abstract = {{In the present work, we provide an electronic structure based method for the “on-the-fly” determination of vibrational sum frequency generation (v-SFG) spectra. The predictive power of this scheme is demonstrated at the air-water interface. While the instantaneous fluctuations in dipole moment are obtained using the maximally localized Wannier functions, the fluctuations in polarizability are approximated to be proportional to the second moment of Wannier functions. The spectrum henceforth obtained captures the signatures of hydrogen bond stretching, bending, as well as low-frequency librational modes.}}, author = {{Ojha, Deepak and Kühne, Thomas D.}}, issn = {{1420-3049}}, journal = {{Molecules}}, title = {{{“On-The-Fly” Calculation of the Vibrational Sum-Frequency Generation Spectrum at the Air-Water Interface}}}, doi = {{10.3390/molecules25173939}}, volume = {{25}}, year = {{2020}}, } @article{19680, abstract = {{This is the second part of a project on the foundations of first-principle calculations of the electron transport in crystals at finite temperatures, aiming at a predictive first-principles platform that combines ab-initio molecular dynamics (AIMD) and a finite-temperature Kubo-formula with dissipation for thermally disordered crystalline phases. The latter are encoded in an ergodic dynamical system (Ω,G,dP), where Ω is the configuration space of the atomic degrees of freedom, G is the space group acting on Ω and dP is the ergodic Gibbs measure relative to the G-action. We first demonstrate how to pass from the continuum Kohn–Sham theory to a discrete atomic-orbitals based formalism without breaking the covariance of the physical observables w.r.t. (Ω,G,dP). Then we show how to implement the Kubo-formula, investigate its self-averaging property and derive an optimal finite-volume approximation for it. We also describe a numerical innovation that made possible AIMD simulations with longer orbits and elaborate on the details of our simulations. Lastly, we present numerical results on the transport coefficients of crystal silicon at different temperatures.}}, author = {{Kühne, Thomas and Heske, Julian Joachim and Prodan, Emil}}, issn = {{0003-4916}}, journal = {{Annals of Physics}}, pages = {{168290}}, title = {{{Disordered crystals from first principles II: Transport coefficients}}}, doi = {{https://doi.org/10.1016/j.aop.2020.168290}}, volume = {{421}}, year = {{2020}}, } @article{19681, author = {{Salem, M. Alaraby and Kühne, Thomas D.}}, issn = {{0026-8976}}, journal = {{Molecular Physics}}, pages = {{1--6}}, title = {{{Insight from energy decomposition analysis on a hydrogen-bond-mediated mechanism for on-water catalysis}}}, doi = {{10.1080/00268976.2020.1797920}}, year = {{2020}}, } @article{19823, abstract = {{Individual grains of chalcopyrite solar cell absorbers can facet in different crystallographic directions at their surfaces. To gain a deeper understanding of the junction formation in these devices, we correlate variations in the surface facet orientation with the defect electronic properties. We use a combined analytical approach based on scanning tunneling spectroscopy (STS), scanning electron microscopy, and electron back scatter diffraction (EBSD), where we perform these experiments on identical surface areas as small as 2 × 2 µm2 with a lateral resolution well below 50 nm. The topography of the absorber surfaces indicates two main morphological features: micro-faceted, long basalt-like columns and their short nano-faceted terminations. Our STS results reveal that the long columns exhibit spectral signatures typical for the presence of pronounced oxidation-induced surface dipoles in conjunction with an increased density of electronic defect levels. In contrast, the nano-faceted terminations of the basalt-like columns are largely passivated in terms of electronic defect levels within the band gap region. Corresponding crystallographic data based on EBSD experiments show that the surface of the basalt-like columns can be assigned to intrinsically polar facet orientations, while the passivated terminations are assigned to non-polar planes. Ab-initio calculations suggest that the polar surfaces are more prone to oxidation and resulting O-induced defects, in comparison to non-polar planes. Our results emphasize the correlation between morphology, surface facet orientations and surface electronic properties. Furthermore, this work aids in gaining a fundamental understanding of oxidation induced lateral inhomogeneities in view of the p-n junction formation in chalcopyrite thin-film solar cells.}}, author = {{Elizabeth, Amala and Conradi, Hauke and K. Sahoo, Sudhir and Kodalle, Tim and A. Kaufmann, Christian and Kühne, Thomas and Mirhosseini, Hossein and Abou-Ras, Daniel and Mönig, Harry}}, issn = {{1359-6454}}, journal = {{Acta Materialia}}, keywords = {{Chalcopyrite absorber, Scanning tunneling spectroscopy, Electron backscatter diffraction, Density functional theory, Surface dipole}}, title = {{{Correlating facet orientation, defect-level density and dipole layer formation at the surface of polycrystalline CuInSe2 thin films}}}, doi = {{https://doi.org/10.1016/j.actamat.2020.09.028}}, volume = {{200}}, year = {{2020}}, } @article{20233, abstract = {{The challenge of designing new tunable nonlinear dielectric materials with tailored properties has attracted an increasing amount of interest recently. Herein, we study the effective nonlinear dielectric response of a stochastic paraelectric-dielectric composite consisting of equilibrium distributions of circular and partially penetrable disks (or parallel, infinitely long, identical, partially penetrable, circular cylinders) of a dielectric phase randomly dispersed in a continuous matrix of a paraelectric phase. The random microstructures were generated using the Metropolis Monte Carlo algorithm. The evaluation of the effective permittivity and tunability were carried out by employing either a Landau thermodynamic model or its Johnson’s approximation to describe the field-dependent permittivity of the paraelectric phase and solving continuum-electrostatics equations using finite element calculations. We reveal that the percolation threshold in this composite governs the critical behavior of the effective permittivity and tunability. For microstructures below the percolation threshold, our simulations demonstrate a strong nonlinear behaviour of the field-dependent effective permittivity and very high tunability that increases as a function of dielectric phase concentration. Above the percolation threshold, the effective permittivity shows the tendency to linearization and the tunability dramatically drops down. The highly reduced permittivity and extraordinarily high tunability are obtained for the composites with dielectric impenetrable disks at high concentrations, in which the triggering of the percolation transition is avoided. The reported results cast light on distinct nonlinear behaviour of 2D and 3D stochastic composites and can guide the design of novel composites with the controlled morphology and tailored permittivity and tunability.}}, author = {{Myroshnychenko, Viktor and Smirnov, Stanislav and Jose, Pious Mathews Mulavarickal and Brosseau, Christian and Förstner, Jens}}, issn = {{1359-6454}}, journal = {{Acta Materialia}}, pages = {{116432}}, title = {{{Nonlinear dielectric properties of random paraelectric-dielectric composites}}}, doi = {{10.1016/j.actamat.2020.10.051}}, volume = {{203}}, year = {{2020}}, } @article{21239, abstract = {{The electrochemical nitrogen reduction reaction (NRR) to ammonia (NH3) is a promising alternative route for an NH3 synthesis at ambient conditions to the conventional high temperature and pressure Haber--Bosch process without the need for hydrogen gas. Single metal ions or atoms are attractive candidates for the catalytic activation of non-reactive nitrogen (N2), and for future targeted improvement of NRR catalysts, it is of utmost importance to get detailed insights into structure-performance relationships and mechanisms of N2 activation in such structures. Here, we report density functional theory studies on the NRR catalyzed by single Au and Fe atoms supported in graphitic C2N materials. Our results show that the metal atoms present in the structure of C2N are the reactive sites, which catalyze the aforesaid reaction by strong adsorption and activation of N2. We further demonstrate that a lower onset electrode potential is required for Fe--C2N than for Au--C2N. Thus, Fe--C2N is theoretically predicted to be a potentially better NRR catalyst at ambient conditions than Au--C2N owing to the larger adsorption energy of N2 molecules. Furthermore, we have experimentally shown that single sites of Au and Fe supported on nitrogen-doped porous carbon are indeed active NRR catalysts. However, in contrast to our theoretical results, the Au-based catalyst performed slightly better with a Faradaic efficiency (FE) of 10.1{\%} than the Fe-based catalyst with an FE of 8.4{\%} at −0.2 V vs. RHE. The DFT calculations suggest that this difference is due to the competitive hydrogen evolution reaction and higher desorption energy of ammonia.}}, author = {{Sahoo, Sudhir K. and Heske, Julian Joachim and Antonietti, Markus and Qin, Qing and Oschatz, Martin and Kühne, Thomas}}, journal = {{ACS Applied Energy Materials}}, number = {{10}}, pages = {{10061--10069}}, publisher = {{American Chemical Society}}, title = {{{Electrochemical N2 Reduction to Ammonia Using Single Au/Fe Atoms Supported on Nitrogen-Doped Porous Carbon}}}, doi = {{10.1021/acsaem.0c01740}}, volume = {{3}}, year = {{2020}}, } @misc{21324, author = {{Chandrakar, Khushboo}}, title = {{{Comparison of Feature Selection Techniques to Improve Approximate Circuit Synthesis}}}, year = {{2020}}, } @inproceedings{21534, author = {{Bengs, Viktor and Hüllermeier, Eyke}}, booktitle = {{International Conference on Machine Learning}}, pages = {{778--787}}, title = {{{Preselection Bandits}}}, year = {{2020}}, } @unpublished{21536, abstract = {{We consider a resource-aware variant of the classical multi-armed bandit problem: In each round, the learner selects an arm and determines a resource limit. It then observes a corresponding (random) reward, provided the (random) amount of consumed resources remains below the limit. Otherwise, the observation is censored, i.e., no reward is obtained. For this problem setting, we introduce a measure of regret, which incorporates the actual amount of allocated resources of each learning round as well as the optimality of realizable rewards. Thus, to minimize regret, the learner needs to set a resource limit and choose an arm in such a way that the chance to realize a high reward within the predefined resource limit is high, while the resource limit itself should be kept as low as possible. We derive the theoretical lower bound on the cumulative regret and propose a learning algorithm having a regret upper bound that matches the lower bound. In a simulation study, we show that our learning algorithm outperforms straightforward extensions of standard multi-armed bandit algorithms.}}, author = {{Bengs, Viktor and Hüllermeier, Eyke}}, booktitle = {{arXiv:2011.00813}}, title = {{{Multi-Armed Bandits with Censored Consumption of Resources}}}, year = {{2020}}, } @inproceedings{21541, abstract = {{In this publication, the near-field to far-field transformation using the self-built near-field scanner NFS3000 is examined with regard to its geometry. This device allows to measure electric and magnetic fields in small distances to the DUT (Device under Test) with high geometric precision and high sensitivity. Leading to a fast examination of EMC (Electromagnetic Compatibility) problems, because the electromagnetic properties are better understandable and therefore easier to solve than e.g. measurements in a far-field chamber. In addition, it is possible to extrapolate the near-fields into the far-field and to determine the radiation pattern of antennas and emitting objects. For this purpose, this paper deals with the basis of this transformation, the so-called surface equivalence theorem. This principle is then adapted to the measurement of near-field scanners and implemented accordingly. Due to the non-ideal design of the near-field scanner, the effects on a far-field transformation are finally presented and discussed.}}, author = {{Lange, Sven and Schroder, Dominik and Hedayat, Christian and Hangmann, Christian and Otto, Thomas and Hilleringmann, Ulrich}}, booktitle = {{2020 International Symposium on Electromagnetic Compatibility - EMC EUROPE}}, isbn = {{978-1-7281-5580-7}}, issn = {{2325-0364 }}, keywords = {{Near-Field Scanner, Near-Field to Far-Field Transformation, Directivity, Surface Equivalence Theorem, Huygens’ Box}}, location = {{Rome, Italy }}, publisher = {{IEEE}}, title = {{{Investigation of the Surface Equivalence Principle on a Metal Surface for a Near-Field to Far-Field Transformation by the NFS3000}}}, doi = {{10.1109/emceurope48519.2020.9245697}}, year = {{2020}}, } @inbook{21542, abstract = {{Using near-field (NF) scan data to predict the far-field (FF) behaviour of radiating electronic systems represents a novel method to accompany the whole RF design process. This approach involves so-called Huygens' box as an efficient radiation model inside an electromagnetic (EM) simulation tool and then transforms the scanned NF measured data into the FF. For this, the basic idea of the Huygens'box principle and the NF-to-FF transformation are briefly presented. The NF is measured on the Huygens' box around a device under test using anNF scanner, recording the magnitude and phase of the site-related magnetic and electric components. A comparison between a fullwave simulation and the measurement results shows a good similarity in both the NF and the simulated and transformed FF.Thus, this method is applicable to predict the FF behaviour of any electronic system by measuring the NF. With this knowledge, the RF design can be improved due to allowing a significant reduction of EM compatibility failure at the end of the development flow. In addition, the very efficient FF radiation model can be used for detailed investigations in various environments and the impact of such an equivalent radiation source on other electronic systems can be assessed.}}, author = {{Schröder, Dominik and Lange, Sven and Hangmann, Christian and Hedayat, Christian}}, booktitle = {{Tensorial Analysis of Networks (TAN) Modelling for PCB Signal Integrity and EMC Analysis}}, isbn = {{9781839530494}}, keywords = {{Huygens' box, NF-to-FF transformation, efficient FF radiation model, FF behaviour, EMI assessment, PCB, near-field measurements, efficient radiation model, far-field behaviour, RF design process, far-field prediction, Huygens'box principle, fullwave simulation, electronic system radiation, equivalent radiation source, electromagnetic simulation tool, near-field scan data, EM compatibility failure reduction}}, pages = {{315--346 (32)}}, publisher = {{ The Institution of Engineering and Technology (IET)}}, title = {{{Far-field prediction combining simulations with near-field measurements for EMI assessment of PCBs}}}, doi = {{10.1049/pbcs072e_ch14}}, year = {{2020}}, } @article{17379, author = {{Kumar Sahoo, Sudhir and Heske, Julian Joachim and Azadi, Sam and Zhang, Zhenzhe and V Tarakina, Nadezda and Oschatz, Martin and Z. Khaliullin, Rustam and Antonietti, Markus and Kühne, Thomas}}, journal = {{Scientific Reports}}, number = {{1}}, title = {{{On the Possibility of Helium Adsorption in Nitrogen Doped Graphitic Materials}}}, doi = {{10.1038/s41598-020-62638-z}}, volume = {{10}}, year = {{2020}}, } @article{17381, author = {{Elgabarty, Hossam and Kampfrath, Tobias and Bonthuis, Douwe Jan and Balos, Vasileios and Kaliannan, Naveen Kumar and Loche, Philip and Netz, Roland R. and Wolf, Martin and K{\, Thomas D. and Sajadi, Mohsen}}, journal = {{Science Advances}}, number = {{17}}, publisher = {{American Association for the Advancement of Science}}, title = {{{Energy transfer within the hydrogen bonding network of water following resonant terahertz excitation}}}, doi = {{10.1126/sciadv.aay7074}}, volume = {{6}}, year = {{2020}}, } @article{17382, author = {{Rengaraj, Varadarajan and Lass, Michael and Plessl, Christian and Kühne, Thomas D.}}, issn = {{2079-3197}}, journal = {{Computation}}, number = {{2}}, pages = {{39}}, publisher = {{MDPI AG}}, title = {{{Accurate Sampling with Noisy Forces from Approximate Computing}}}, doi = {{10.3390/computation8020039}}, volume = {{8}}, year = {{2020}}, } @article{17386, author = {{Kühne, Thomas D. and Iannuzzi, Marcella and Del Ben, Mauro and Rybkin, Vladimir V. and Seewald, Patrick and Stein, Frederick and Laino, Teodoro and Khaliullin, Rustam Z. and Schütt, Ole and Schiffmann, Florian and al., et}}, issn = {{1089-7690}}, journal = {{The Journal of Chemical Physics}}, number = {{19}}, pages = {{194103}}, publisher = {{AIP Publishing}}, title = {{{CP2K: An electronic structure and molecular dynamics software package - Quickstep: Efficient and accurate electronic structure calculations}}}, doi = {{10.1063/5.0007045}}, volume = {{152}}, year = {{2020}}, } @inproceedings{17407, author = {{Tornede, Alexander and Wever, Marcel Dominik and Hüllermeier, Eyke}}, booktitle = {{Discovery Science}}, title = {{{Extreme Algorithm Selection with Dyadic Feature Representation}}}, year = {{2020}}, } @inproceedings{17408, author = {{Hanselle, Jonas Manuel and Tornede, Alexander and Wever, Marcel Dominik and Hüllermeier, Eyke}}, booktitle = {{KI 2020: Advances in Artificial Intelligence}}, title = {{{Hybrid Ranking and Regression for Algorithm Selection}}}, year = {{2020}}, } @inproceedings{17424, author = {{Tornede, Tanja and Tornede, Alexander and Wever, Marcel Dominik and Mohr, Felix and Hüllermeier, Eyke}}, booktitle = {{Proceedings of the ECMLPKDD 2020}}, title = {{{AutoML for Predictive Maintenance: One Tool to RUL Them All}}}, doi = {{10.1007/978-3-030-66770-2_8}}, year = {{2020}}, }