TY - CHAP AU - Peckhaus, Volker ED - Hermann, Kay ED - Schwitzer, Boris ID - 44860 T2 - Der Geist der kritischen Schule. Kantisches Denken in der Tradition von Jakob Friedrich Fries und Leonard Nelson im 20. Jahrhundert: Wirkungen und Aktualität TI - Kritische Mathematik und die Axiomatik Hilberts ER - TY - JOUR AB - Data-driven models for nonlinear dynamical systems based on approximating the underlying Koopman operator or generator have proven to be successful tools for forecasting, feature learning, state estimation, and control. It has become well known that the Koopman generators for control-affine systems also have affine dependence on the input, leading to convenient finite-dimensional bilinear approximations of the dynamics. Yet there are still two main obstacles that limit the scope of current approaches for approximating the Koopman generators of systems with actuation. First, the performance of existing methods depends heavily on the choice of basis functions over which the Koopman generator is to be approximated; and there is currently no universal way to choose them for systems that are not measure preserving. Secondly, if we do not observe the full state, we may not gain access to a sufficiently rich collection of such functions to describe the dynamics. This is because the commonly used method of forming time-delayed observables fails when there is actuation. To remedy these issues, we write the dynamics of observables governed by the Koopman generator as a bilinear hidden Markov model, and determine the model parameters using the expectation-maximization (EM) algorithm. The E-step involves a standard Kalman filter and smoother, while the M-step resembles control-affine dynamic mode decomposition for the generator. We demonstrate the performance of this method on three examples, including recovery of a finite-dimensional Koopman-invariant subspace for an actuated system with a slow manifold; estimation of Koopman eigenfunctions for the unforced Duffing equation; and model-predictive control of a fluidic pinball system based only on noisy observations of lift and drag. AU - Otto, Samuel E. AU - Peitz, Sebastian AU - Rowley, Clarence W. ID - 33461 IS - 1 JF - SIAM Journal on Applied Dynamical Systems TI - Learning Bilinear Models of Actuated Koopman Generators from Partially-Observed Trajectories VL - 23 ER - TY - JOUR AB - We show how to learn discrete field theories from observational data of fields on a space-time lattice. For this, we train a neural network model of a discrete Lagrangian density such that the discrete Euler--Lagrange equations are consistent with the given training data. We, thus, obtain a structure-preserving machine learning architecture. Lagrangian densities are not uniquely defined by the solutions of a field theory. We introduce a technique to derive regularisers for the training process which optimise numerical regularity of the discrete field theory. Minimisation of the regularisers guarantees that close to the training data the discrete field theory behaves robust and efficient when used in numerical simulations. Further, we show how to identify structurally simple solutions of the underlying continuous field theory such as travelling waves. This is possible even when travelling waves are not present in the training data. This is compared to data-driven model order reduction based approaches, which struggle to identify suitable latent spaces containing structurally simple solutions when these are not present in the training data. Ideas are demonstrated on examples based on the wave equation and the Schrödinger equation. AU - Offen, Christian AU - Ober-Blöbaum, Sina ID - 46469 IS - 1 JF - Chaos SN - 1054-1500 TI - Learning of discrete models of variational PDEs from data VL - 34 ER - TY - JOUR AU - Harnack, Maria ID - 46081 JF - Graugold. Magazin für Alltagskultur TI - Lebendiges Silberschmiedehandwerk in Westfalen am Beispiel der 1892 gegründeten Werkstatt Cassau in Paderborn ER - TY - CONF AU - Carillo Beber, Vinicius AU - Fernandes, Pedro AU - Nagel, Christof AU - Köster, Christian AU - Matzenmiller, Anton AU - Hecht, Mathias AU - Baumgartner, Jörg AU - Melz, Tobias AU - Tews, Karina AU - Çavdar, Serkan AU - Meschut, Gerson ID - 52215 T2 - 24. Kolloquium: Gemeinsame Forschung in der Klebtechnik TI - Lebensdauerprognose für Stahlklebverbindungen bei multiaxialer Belastung mit Phasenverschiebung, veränderlicher Mittelspannung und variablen Amplituden ER - TY - BOOK ED - Herzig, Bardo ED - Eickelmann, Birgit ED - Schwabl, Franziska ED - Schulze, J. ED - Niemann, Jan ID - 51129 TI - Lehrkräftebildung in der digitalen Welt – zukunftsorientierte Forschungs- und Praxisperspektiven 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 - BOOK AU - Schlieper, Hendrik ID - 49504 TI - Liebestragödie. Genealogien einer französischen Gattung des 17. Jahrhunderts ER - TY - JOUR AB - Superconducting nanowire single-photon detectors (SNSPDs) have been widely used to study the discrete nature of quantum states of light in the form of photon-counting experiments. We show that SNSPDs can also be used to study continuous variables of optical quantum states by performing homodyne detection at a bandwidth of 400 kHz. By measuring the interference of a continuous-wave field of a local oscillator with the field of the vacuum state using two SNSPDs, we show that the variance of the difference in count rates is linearly proportional to the photon flux of the local oscillator over almost five orders of magnitude. The resulting shot-noise clearance of (46.0 ± 1.1) dB is the highest reported clearance for a balanced optical homodyne detector, demonstrating their potential for measuring highly squeezed states in the continuous-wave regime. In addition, we measured a CMRR = 22.4 dB. From the joint click counting statistics, we also measure the phase-dependent quadrature of a weak coherent state to demonstrate our device’s functionality as a homodyne detector. AU - Protte, Maximilian AU - Schapeler, Timon AU - Sperling, Jan AU - Bartley, Tim ID - 50840 IS - 1 JF - Optica Quantum SN - 2837-6714 TI - Low-noise balanced homodyne detection with superconducting nanowire single-photon detectors VL - 2 ER - TY - GEN AB - In order to standardize spray flame synthesis (SFS) studies, intensive work has been done in recent years on the design of burner types. Thus, in 2019, the so-called SpraySyn1 burner was introduced (SS1), which was subsequently characterized in numerical and experimental studies. Based on this research, a modification of the nozzle design was proposed, which has now been considered in the successor model, SpraySyn2 (SS2). As little is known about the effect of the nozzle adaptation on the particle formation, we operated both burners under identical operating conditions to produce maghemite. The final powder comparison showed that SS2 yielded considerable higher specific surface areas (associated with smaller primary particle sizes), lower polydispersity, and higher phase purity. To obtain further information on the size distributions of aggregates and agglomerates generated by SS2, aerosol samples were extracted by hole in a tube (HIAT) sampling and characterized by scanning mobility particle sizing (SMPS). Samples were extracted along the centerline at different heights above the burner (HAB) above the visible flame tip (>7 cm), and quenching experiments were performed to extract the aerosol samples at different dilution rates. Thereby, it was demonstrated that performing detailed quenching experiments is crucial for obtaining representative HIAT-SMPS data. In particular, agglomerates/aggregate sizes were overestimated by up to ~70 % if samples were not sufficiently diluted. If sufficient dilution was applied, distribution widths and mean particle mobility diameters were determined with high accuracy (sample standard derivation <5 %). Our data suggested the evolution of primary particle sizes was mostly completed <7 cm HAB and it was shown aggregates/agglomerates present above the visible flame were compact in structure (non- fractal). The mean diameter of the particle ensemble grew along the centerline from 6.9 nm (7 cm) to 11.4 nm (15 cm), while distribution widths grew from 1.42 to 1.52. ED - Tischendorf, Ricardo ED - Massopo, Orlando ED - Schmid, Hans-Joachim ED - Pyrmak, Olek ED - Dupont, Sophie ED - Fröde, Fabian ED - Pitsch, Heinz ED - Kneer, Reinhold ID - 51133 KW - Flame Spray Pyrolysis KW - SpraySyn2 KW - Spray flame synthesis KW - Maghemite nanoparticles KW - Gas to particle-conversion KW - Hole in a tube sampling T2 - Applications in Energy and Combustion Science TI - Maghemite nanoparticles synthesis via spray flame synthesis and particle characterization by hole in a tube sampling and scanning mobility particle sizing (HIAT-SMPS) ER - TY - CHAP AU - Taschl-Erber, Andrea ED - Annette, Weissenrieder ID - 49815 T2 - Reconsidering the Letter to the Ephesians in Context TI - Making “the Two” Into One Body: De- and Recategorization of (Un-)Circumcision, ER - TY - JOUR AU - Wingenbach, Jan AU - Schumacher, Stefan AU - Ma, Xuekai ID - 51105 JF - Physical Review Research, in press TI - Manipulating spectral topology and exceptional points by nonlinearity in non-Hermitian polariton systems ER - TY - CHAP AU - Taschl-Erber, Andrea ED - Franchi, Roberta ED - Barnes, Aneilya ID - 49816 T2 - More than Female Disciples: An Examination of Women’s Authority in Ancient Christianity (Ist-VIth centuries) TI - Martha and Her Sister(s) – Female Voices in the Fourth Gospel, ER - TY - THES AB - Die Extrusion stellt das mengenmäßig dominante Verarbeitungsverfahren für thermoplastische Kunststoffe dar. Daher gibt es starke Bestrebungen in diesem Bereich hin zu einer höheren Wirtschaftlichkeit, welche beispielsweise durch höheren Massedurchsatz bei gleichbleibender Maschinengröße erreicht werden kann, oder aber auch im Hinblick auf eine Kreislaufwirtschaft die Bestrebung hin zu einer materialschonenden Verarbeitung. Beide Bestrebungen erfordern spezielle Schneckenkonzepte. Hierunter fallenWave- Schnecken, welche in beiden Bereichen ein vorteilhaftes Prozessverhalten aufzeigen sollen. Die Auslegung von Wave-Schnecken erfordert jedoch ein stärkeres Verständnis über das geometrieabhängige Prozessverhalten in der Extrusion. Im Rahmen der Dissertation werden zwei Themengebiete angegangen. Das erste Thema ist die Herleitung einer Methode zur Charakterisierung des Abbauverhaltens von Thermoplasten sowie die Nutzung der Charakterisierung als Vorhersagemodell. Das zweite Thema behandelt die Auslegung von Wave-Schnecken basierend auf numerischen Simulationen samt Validierung anhand von sieben Energy-Transfer-Schnecken im Vergleich zu drei konventionellen Schnecken. Hierbei werden unter anderem der Materialabbau, die thermische und die stoffliche Homogenität betrachtet, um ein umfassendes Bild über das Prozessverhalten der Schnecken zu schaffen. Die vorgestellten Untersuchungen dienen schlussendlich zu einer Bestätigung des vorteilhaften Prozessverhaltens von Wave-Schnecken. AU - Schall, Christoph Wilhelm Theodor ID - 50530 SN - 978-3-8440-9334-6 TI - Materialschonende Verarbeitung von Thermoplasten auf Wave-Schnecken VL - Band 2/2024 ER - TY - CONF AU - Tews, Karina AU - Teutenberg, Dominik AU - Meschut, Gerson ID - 52216 TI - Mechanisches Verhalten: Charakterisierung von Klebstoffen ER - TY - BOOK AU - Christian, Fuchs ID - 49088 TI - Media, Economy and Society: A Critical Introduction. ER - TY - CHAP AU - Welsandt, N.J. AU - Huschle, L. AU - Drossel, Kerstin AU - Deimel, D. AU - Abs, H.J. ED - Abs, H.J. ED - Hahn-Laudenberg, K. ED - Deimel, D. ED - Ziemes, J.F. ID - 51099 T2 - ICCS 2022. Schulische Sozialisation und politische Bildung von 14-Jährigen im internationalen Vergleich TI - Mediennutzung von Jugendlichen zu sozialen und politischen Fragen, schulische Aktivitäten und Lehrkräftefortbildungen ER - TY - BOOK ED - Blumberg, Eva ED - Niederhaus, Constanze ED - Mischendahl, Anne ID - 40014 TI - Mehrsprachigkeit in der Schule. Sprachbildung im und durch Sachunterricht. ER - TY - CONF AU - Beule, Felix AU - Sander, Sascha AU - Meschut, Gerson AU - Damm, Jannis AU - Kasper, Yann AU - Albiez, Matthias AU - Kötz, Fabian AU - Matzenmiller, Anton ID - 52213 T2 - 24. Kolloquium: Gemeinsame Forschung in der Klebtechnik TI - Methodenentwicklung zur rechnerischen Auslegung geklebter Stahlverbindungen unter Alterungsbeanspruchung im Stahl- und Anlagenbau ER - TY - GEN AU - Al Trjman, Mohamad AU - Meschut, Gerson AU - Salten, Alexander Heinrich Johannes AU - Kenig, Eugeny Y. ID - 52403 TI - Methodenentwicklung zur Simulation des Viscous Fingering in Klebverbindungen von stahlintensiven Mischbaustrukturen ER -