TY - JOUR AU - Huybrechts, Yves AU - Karaca, Resul ID - 49772 JF - Synergies Pays germanophones SN - 1866-5268 TI - BelgienNet – une plateforme pour l’accès aux langues et cultures de la Belgique VL - 16 ER - TY - JOUR AU - Moretto, Giordano AU - Schnell, Nicolas AU - Frey, Jonathan AU - Karakaya, Yasin AU - Amstutz, Alois AU - Diehl, Moritz AU - Kasper, Tina AU - Onder, Christopher ID - 50841 JF - Control Engineering Practice TI - Fast model-based calibration of multiple injections for a CI engine using nonlinear optimal control VL - 145 ER - TY - JOUR AB - Ferroelectric domain wall (DW) conductivity (DWC) can be attributed to two separate mechanisms: (a) the injection/ejection of charge carriers across the Schottky barrier formed at the (metal-)electrode-DW junction and (b) the transport of those charge carriers along the DW. Current-voltage (I-U) characteristics, recorded at variable temperatures from LiNbO3 (LNO) DWs, are clearly able to differentiate between these two contributions. Practically, they allow us to directly quantify the physical parameters relevant to the two mechanisms (a) and (b) mentioned above. These are, for example, the resistance of the DW, the saturation current, the ideality factor, and the Schottky barrier height of the electrode-DW junction. Furthermore, the activation energies needed to initiate the thermally activated electronic transport along the DWs can be extracted. In addition, we show that electronic transport along LNO DWs can be elegantly viewed and interpreted in an adapted semiconductor picture based on a double-diode, double-resistor equivalent-circuit model, the R2D2 model. Finally, our R2D2 model was checked for its universality by successfully fitting the I-U curves of not only z-cut LNO bulk DWs, but equally of z-cut thin-film LNO DWs, and of x-cut thin-film DWs as reported in literature. AU - Zahn, Manuel AU - Beyreuther, Elke AU - Kiseleva, Iuliia AU - Lotfy, Ahmed Samir AU - McCluskey, Conor J. AU - Maguire, Jesi R. AU - Suna, Ahmet AU - Rüsing, Michael AU - Gregg, J. Marty AU - Eng, Lukas M. ID - 51156 IS - 2 JF - Physical Review Applied KW - General Physics and Astronomy SN - 2331-7019 TI - Equivalent-circuit model that quantitatively describes domain-wall conductivity in ferroelectric lithium VL - 21 ER - TY - GEN AB - We rigorously derive novel and sharp finite-data error bounds for highly sample-efficient Extended Dynamic Mode Decomposition (EDMD) for both i.i.d. and ergodic sampling. In particular, we show all results in a very general setting removing most of the typically imposed assumptions such that, among others, discrete- and continuous-time stochastic processes as well as nonlinear partial differential equations are contained in the considered system class. Besides showing an exponential rate for i.i.d. sampling, we prove, to the best of our knowledge, the first superlinear convergence rates for ergodic sampling of deterministic systems. We verify sharpness of the derived error bounds by conducting numerical simulations for highly-complex applications from molecular dynamics and chaotic flame propagation. AU - Philipp, Friedrich M. AU - Schaller, Manuel AU - Boshoff, Septimus AU - Peitz, Sebastian AU - Nüske, Feliks AU - Worthmann, Karl ID - 51160 T2 - arXiv:2402.02494 TI - Extended Dynamic Mode Decomposition: Sharp bounds on the sample efficiency ER - TY - GEN AU - Peckhaus, Volker ED - Zalta, Edward N.. ED - Nodelman, Uri ID - 17740 T2 - The Stanford Encyclopedia of Philosophy, first published Sep 4, 2009, substantive revision Feb 2, 2024 TI - Leibniz’s Influence on 19th Century Logic ER - TY - GEN AU - Schmidt, Rebecca ID - 51301 T2 - SozMethode TI - Automatische Transkriptionssoftware – ein Erfahrungsbericht. ER - TY - JOUR AU - Weich, Tobias AU - Guedes Bonthonneau, Yannick AU - Guillarmou, Colin AU - Hilgert, Joachim ID - 32101 JF - J. Europ. Math. Soc. TI - Ruelle-Taylor resonaces of Anosov actions ER - TY - GEN AU - Hilgert, Joachim ID - 51501 TI - Quantum-Classical Correspondences for Locally Symmetric Spaces ER - TY - JOUR AU - Cui, Tie Jun AU - Zhang, Shuang AU - Alu, Andrea AU - Wegener, Martin AU - Pendry, John AU - Luo, Jie AU - Lai, Yun AU - Wang, Zuojia AU - Lin, Xiao AU - Chen, Hongsheng AU - Chen, Ping AU - Wu, Rui-Xin AU - Yin, Yuhang AU - Zhao, Pengfei AU - Chen, Huanyang AU - Li, Yue AU - Zhou, Ziheng AU - Engheta, Nader AU - Asadchy, V. S. AU - Simovski, Constantin AU - Tretyakov, Sergei A AU - Yang, Biao AU - Campbell, Sawyer D. AU - Hao, Yang AU - Werner, Douglas H AU - Sun, Shulin AU - Zhou, Lei AU - Xu, Su AU - Sun, Hong-Bo AU - Zhou, Zhou AU - Li, Zile AU - Zheng, Guoxing AU - Chen, Xianzhong AU - Li, Tao AU - Zhu, Shi-Ning AU - Zhou, Junxiao AU - Zhao, Junxiang AU - Liu, Zhaowei AU - Zhang, Yuchao AU - Zhang, Qiming AU - Gu, Min AU - Xiao, Shumin AU - Liu, Yongmin AU - Zhang, Xiaoyu AU - Tang, Yutao AU - Li, Guixin AU - Zentgraf, Thomas AU - Koshelev, Kirill AU - Kivshar, Yuri S. AU - Li, Xin AU - Badloe, Trevon AU - Huang, Lingling AU - Rho, Junsuk AU - Wang, Shuming AU - Tsai, Din Ping AU - Bykov, A. Yu. AU - Krasavin, Alexey V AU - Zayats, Anatoly V AU - McDonnell, Cormac AU - Ellenbogen, Tal AU - Luo, Xiangang AU - Pu, Mingbo AU - Garcia-Vidal, Francisco J AU - Liu, Liangliang AU - Li, Zhuo AU - Tang, Wenxuan AU - Ma, Hui Feng AU - Zhang, Jingjing AU - Luo, Yu AU - Zhang, Xuanru AU - Zhang, Hao Chi AU - He, Pei Hang AU - Zhang, Le Peng AU - Wan, Xiang AU - Wu, Haotian AU - Liu, Shuo AU - Jiang, Wei Xiang AU - Zhang, Xin Ge AU - Qiu, Chengwei AU - Ma, Qian AU - Liu, Che AU - Li, Long AU - Han, Jiaqi AU - Li, Lianlin AU - Cotrufo, Michele AU - Caloz, Christophe AU - Deck-Léger, Z.-L. AU - Bahrami, A. AU - Céspedes, O. AU - Galiffi, Emanuele AU - Huidobro, P. A. AU - Cheng, Qiang AU - Dai, Jun Yan AU - Ke, Jun Cheng AU - Zhang, Lei AU - Galdi, Vincenzo AU - Di Renzo, Marco ID - 51519 JF - Journal of Physics: Photonics KW - Electrical and Electronic Engineering KW - Atomic and Molecular Physics KW - and Optics KW - Electronic KW - Optical and Magnetic Materials SN - 2515-7647 TI - Roadmap on electromagnetic metamaterials and metasurfaces ER - TY - GEN AU - Staffel, Florian Lukas ID - 51624 IS - 2 T2 - Sehepunkte TI - Christian Marx: Wegbereiter der Globalisierung. Multinationale Unternehmen der westeuropäischen Chemieindustrie in der Zeit nach dem Boom (1960er-2000er Jahre) (= Nach dem Boom), Göttingen 2023. VL - 24 ER - TY - JOUR AB - We derive efficient algorithms to compute weakly Pareto optimal solutions for smooth, convex and unconstrained multiobjective optimization problems in general Hilbert spaces. To this end, we define a novel inertial gradient-like dynamical system in the multiobjective setting, which trajectories converge weakly to Pareto optimal solutions. Discretization of this system yields an inertial multiobjective algorithm which generates sequences that converge weakly to Pareto optimal solutions. We employ Nesterov acceleration to define an algorithm with an improved convergence rate compared to the plain multiobjective steepest descent method (Algorithm 1). A further improvement in terms of efficiency is achieved by avoiding the solution of a quadratic subproblem to compute a common step direction for all objective functions, which is usually required in first-order methods. Using a different discretization of our inertial gradient-like dynamical system, we obtain an accelerated multiobjective gradient method that does not require the solution of a subproblem in each step (Algorithm 2). While this algorithm does not converge in general, it yields good results on test problems while being faster than standard steepest descent. AU - Sonntag, Konstantin AU - Peitz, Sebastian ID - 46019 JF - Journal of Optimization Theory and Applications TI - Fast Multiobjective Gradient Methods with Nesterov Acceleration via Inertial Gradient-Like Systems ER - TY - GEN AB - The efficient optimization method for locally Lipschitz continuous multiobjective optimization problems from [1] is extended from finite-dimensional problems to general Hilbert spaces. The method iteratively computes Pareto critical points, where in each iteration, an approximation of the subdifferential is computed in an efficient manner and then used to compute a common descent direction for all objective functions. To prove convergence, we present some new optimality results for nonsmooth multiobjective optimization problems in Hilbert spaces. Using these, we can show that every accumulation point of the sequence generated by our algorithm is Pareto critical under common assumptions. Computational efficiency for finding Pareto critical points is numerically demonstrated for multiobjective optimal control of an obstacle problem. AU - Sonntag, Konstantin AU - Gebken, Bennet AU - Müller, Georg AU - Peitz, Sebastian AU - Volkwein, Stefan ID - 51334 T2 - arXiv:2402.06376 TI - A Descent Method for Nonsmooth Multiobjective Optimization in Hilbert Spaces ER - TY - GEN AB - Estimating the infection risks in indoor environments comprises the assessment of the behavior of virus-laden aerosols, i.e. spreading, mixing, removal by air purifiers etc. A promising experimental approach is based on using non-hazardous surrogate aerosols of similar size, e.g. salt particles, to mimic the virus aerosol behavior. This manuscript addresses the issue how a successful transfer of such experiments can be accomplished. Corresponding experiments in two very different environments, a large community hall and a seminar room, with optional use of air purifiers in various constellations were conducted. While high particle concentrations are advantageous in terms of avoiding influence of background aerosol concentrations, it is shown that appropriate consideration of aggregation and settling are vital to theoretically describe the experimentally determined course of particle concentrations. A corresponding model equation for a well-mixed situation is derived and the required parameters are thoroughly determined in separate experiments independently. It is demonstrated that clean air delivery rates (CADR) of air purifiers determined with this approach may differ substantially from common approaches not explicitly taking into account aggregation. AU - Beimdiek, Janis AU - Schmid, Hans-Joachim ID - 51731 KW - surrogate aerosols KW - indoor air cleaners KW - ultra-fine particles KW - COVID-19 KW - test method KW - field experiments: clean air delivery rate T2 - Atmosphere TI - Evaluation of Surrogate Aerosol Experiments to Predict Spreading and Removal of Virus-Laden Aerosols ER - TY - CHAP AU - Richter, Susanne ED - Kieslinger, Daniel ED - Owsianowski, Judith ID - 51790 SN - 978-3-7841-3666-0 T2 - Inklusiver Kinderschutz – Anforderungen, Herausforderungen, Perspektiven TI - Herausforderungen in der inklusiven Mädchenarbeit: Begleitforschung der „Inklusiven anonymen Zuflucht“ des Mädchenhaus Bielefeld e.V. ER - TY - JOUR AB - We present a convolutional framework which significantly reduces the complexity and thus, the computational effort for distributed reinforcement learning control of dynamical systems governed by partial differential equations (PDEs). Exploiting translational equivariances, the high-dimensional distributed control problem can be transformed into a multi-agent control problem with many identical, uncoupled agents. Furthermore, using the fact that information is transported with finite velocity in many cases, the dimension of the agents’ environment can be drastically reduced using a convolution operation over the state space of the PDE, by which we effectively tackle the curse of dimensionality otherwise present in deep reinforcement learning. In this setting, the complexity can be flexibly adjusted via the kernel width or by using a stride greater than one (meaning that we do not place an actuator at each sensor location). Moreover, scaling from smaller to larger domains – or the transfer between different domains – becomes a straightforward task requiring little effort. We demonstrate the performance of the proposed framework using several PDE examples with increasing complexity, where stabilization is achieved by training a low-dimensional deep deterministic policy gradient agent using minimal computing resources. AU - Peitz, Sebastian AU - Stenner, Jan AU - Chidananda, Vikas AU - Wallscheid, Oliver AU - Brunton, Steven L. AU - Taira, Kunihiko ID - 40171 JF - Physica D: Nonlinear Phenomena TI - Distributed Control of Partial Differential Equations Using Convolutional Reinforcement Learning VL - 461 ER - TY - JOUR AB - athematische Kompetenzen digital zu fördern und digitale Kompetenzen mathematisch zu fördern – dies ist eine Forderung der neuen Bildungsstandards mit Blick auf eine Bildung in der digitalen Welt. Gerade das Potenzial digitaler Medien für das fachliche Lernen wurde in vielen Studien bestätigt. Eine sinnvoll gestaltete Einbettung digitaler Medien bietet die Chance, allen fünf Prinzipien eines guten Unterrichts gerecht zu werden: Verstehensorientierung, Durchgängigkeit, kognitive Aktivierung, Lernendenorientierung & Adaptivität und Kommunikationsförderung. Die flächendeckende Nutzung digitaler Medien etabliert sich bislang nur zögerlich. Aber wie können wir Lehrkräfte stärken, digitale Medien sinnvoll einzusetzen? Wir möchten hier die Bandbreite der Möglichkeiten an Beispielen verdeutlichen, ihren Einsatz motivieren und Wege für einen guten Unterricht aufzeigen. AU - Barzel, Bärbel AU - Greefrath, Gilbert AU - Nagel, Mareike AU - Hoffmann, Max ID - 51841 JF - mathematik lehren TI - Digitalisierung als Chance für alle Prinzipien guten Unterrichts VL - 242 ER - TY - GEN AU - Riedl, Lars ID - 50728 SN - 978-3-8376-6682 T2 - Kölner Zeitschrift für Soziologie und Sozialpsychologie TI - Soziologie des Flitzers ER - TY - JOUR AB - In der Professionalisierung von Lehrkräften ist die Selbst-reflexion eine wesentliche Voraussetzung, da sie zentral für die Weiterentwicklung der eigenen Kompetenzen ist. Daraus ergibt sich die Notwendigkeit, bereits in der ersten Phase der Lehrkräftebildung die Selbstreflexion und die Weiterentwicklungsorientierung zu fördern. Hierzu sind auf Grund des sozialen Settings gezielte reflexionsorientierte Workshops chancenreich. Um die Effekte von reflexionsorientierten Workshops und dabei den Zusammenhang zwischen der Selbst-reflexion und der Weiterentwicklungsorientierung zu überprüfen, wurden anhand einer Stichprobe von N = 646 Lehramtsstudierenden die Entwicklung der Selbst-reflexion und Weiterentwicklungsorientierung beim Besuch von Workshops zu überfachlichen Kompetenzen untersucht. Die Datenerhebung erfolgte vor, direkt nach und erneut vier bis sechs Wochen nach den reflexionsorientierten Workshops mittels eines Fragebogens. Durch Varianzanalysen können in Bezug auf die Selbst-reflexion direkt nach den Workshops signifikante Effekte sowie eine konstante Ausprägung vier bis sechs Wochen später nachgewiesen werden. Weiterhin konnte ein signifikanter Anstieg bei der Weiterentwicklungsorientierung über die drei Messzeitpunkte verzeichnet werden. Ebenso zeigte sich ein positiver Effekt der Selbstreflexion auf den Anstieg der Weiterentwicklungsorientierung. AU - Kleine, Sabrina M AU - Sohlau, Sylvia AU - Seifert, Andreas AU - Buhl, Heike M. ID - 52328 IS - 1 JF - Herausforderung Lehrer*innenbildung - Zeitschrift zur Konzeption, Gestaltung und Diskussion TI - Förderung der Selbstreflexion und Weiterentwicklungsorientierung durch reflexionsorientierte Workshops im Lehramtsstudium VL - 7 ER - TY - JOUR AU - Beimdiek, Janis AU - Schmid, Hans-Joachim ID - 52357 IS - 3 JF - Atmosphere KW - surrogate aerosols KW - indoor air cleaners KW - ultra-fine particles KW - COVID-19 KW - test method KW - field experiments: clean air delivery rate SN - 2073-4433 TI - Evaluation of Surrogate Aerosol Experiments to Predict Spreading and Removal of Virus-Laden Aerosols VL - 15 ER - TY - JOUR AU - Al-Lami, Abbas J.S. AU - Kenig, Eugeny Y. ID - 51122 JF - Case Studies in Thermal Engineering KW - Fluid Flow and Transfer Processes KW - Engineering (miscellaneous) SN - 2214-157X TI - New pressure drop and heat transfer correlations for turbulent forced convection in internally channeled tube heat exchanger ducts ER -