@inproceedings{21813, author = {{Hansmeier, Tim and Platzner, Marco}}, booktitle = {{GECCO '21: Proceedings of the Genetic and Evolutionary Computation Conference Companion}}, isbn = {{978-1-4503-8351-6}}, location = {{Lille, France}}, pages = {{1639–1647}}, publisher = {{Association for Computing Machinery (ACM)}}, title = {{{An Experimental Comparison of Explore/Exploit Strategies for the Learning Classifier System XCS}}}, doi = {{10.1145/3449726.3463159}}, year = {{2021}}, } @inproceedings{25265, abstract = {{Waveguide-based methods can be used for the non-destructive determination of acoustic material parameters. One of these methods is based on transmission measurements of cylindrical polymeric specimens. Here, the experimental setup consists of two transducers, which excite and receive the waveguide modes at the faces of the cylinder. The measurement, as well as a forward model, are used to determine material parameters of the polymeric specimen in an inverse approach. 1-3 piezoelectric composites are used as an active element because they can be approximated by a thickness vibration only. This allows an easy identification of Mason model parameters to characterise the transducers’ vibration behaviour. However, sensitivity analysis shows a high uncertainty in the determination of the mechanical shear parameters due to the uniform excitation. To increase the sensitivity to these shear motions, arbitrary excitations were investigated by means of numerical simulation. In order to be able to realise the determined optimal excitation, new transducer prototypes were designed. By subdividing the electrodes of the active element, for example, ring-shaped excitation is feasible. Furthermore, it can be shown that modelling these transducers with a one-dimensional Mason model is sufficient.}}, author = {{Dreiling, Dmitrij and Itner, Dominik and Feldmann, Nadine and Scheidemann, Claus and Gravenkamp, Hauke and Henning, Bernd}}, booktitle = {{Fortschritte der Akustik - DAGA 2021}}, location = {{Wien}}, publisher = {{Deutsche Gesellschaft für Akustik e.V. (DEGA)}}, title = {{{Application and modelling of ultrasonic transducers using 1-3 piezoelectric composites with structured electrodes}}}, year = {{2021}}, } @inproceedings{24229, author = {{Buckmann, Felix and Kenig, Eugeny}}, location = {{online}}, title = {{{Experimentelle Untersuchungen zum Kondensationsverhalten von Wasserdampf im Spalt zwischen Kissenplatten}}}, year = {{2021}}, } @inproceedings{24230, author = {{Buckmann, Felix and Kenig, Eugeny}}, location = {{online}}, title = {{{Condensation in pillow-plate heat exchangers: Experiments with pure substances}}}, year = {{2021}}, } @phdthesis{21502, abstract = {{Die vollständige Beschreibung fluiddynamischer und akustischer Vorgänge setzt voraus, dass die Eigenschaften des Fluids hinlänglich bekannt sind.Während Fluidkenngrößen, wie etwa die Schallgeschwindigkeit oder die Scherviskosität, für viele Flüssigkeiten über weite Bereiche des thermodynamischen Zustandsraums bekannt sind, existieren für die Volumenviskosität nur eine geringe Anzahl Messdaten.In dieser Arbeit wird daher ein Messverfahren zur selektiven Bestimmung der Volumenviskosität von Flüssigkeiten, basierend auf der Absorption von Ultraschallwellen, entwickelt und realisiert.Schwerpunkte bilden dabei der simulationsgestützte Entwurf von Algorithmen zur Auswertung der Messsignale sowie die Analyse und Weiterentwicklung einer Messanordnung, basierend auf dem Puls-Echo-Verfahren. Neben der Absorption im Fluid treten dabei weitere Effekte (zum Beispiel Beugung oder unvollständige Reflexion) auf, die das akustische Signal schwächen oder anderweitig beeinflussen. Die Entwicklung von Verfahren zur Trennung dieser Effekte von der akustischen Absorption bildet daher einen weiteren Schwerpunkt dieser Arbeit.Abschließend wird die Volumenviskosität aus der gemessenen akustischen Absorption für unterschiedliche Fluide in verschiedenen thermodynamischen Zuständen unter Zuhilfenahme anderer bekannter Fluidkenngrößen bestimmt sowie eine Unsicherheitsbetrachtung durchgeführt.}}, author = {{Claes, Leander}}, pages = {{223}}, publisher = {{Universiät Paderborn}}, title = {{{Messverfahren für die akustische Absorption in reinen Fluiden zur Bestimmung der Volumenviskosität}}}, doi = {{10.17619/UNIPB/1-1104}}, year = {{2021}}, } @misc{21233, author = {{Schulze, Veronika and Schmidt, Stephan and Jurgelucks, Benjamin and Feldmann, Nadine and Claes, Leander}}, title = {{{Optimal experiment design with respect to electrode configurations for a piezoelectric problem}}}, year = {{2021}}, } @article{21341, abstract = {{The progress in numerical methods and simulation tools promotes the use of inverse problems in material characterisation problems. A newly developed procedure can be used to identify the behaviour of piezoceramic discs over a wide frequency range using a single specimen via fitting simulated and measured impedances by optimising the underlying material parameters. Since there is no generally accepted damping model for piezoelectric ceramics, several mechanical damping models are examined for the material identification. Three models have been chosen and their ability to replicate the measured impedances is evaluated. On the one hand, the common Rayleigh model is considered as a reference. On the other hand, a Zener model and a model using complex constants are extended to model the transversely isotropic material. As the Rayleigh model is only valid for a limited frequency range, it fails to model the broadband behaviour of the material. The model using complex constants leads to the best fit over a wide frequency range while at the same time only adding three additional parameters for modelling damping. Thus, damping can be assumed approximately frequency-independent in piezoceramics.}}, author = {{Feldmann, Nadine and Schulze, Veronika and Claes, Leander and Jurgelucks, Benjamin and Meihost, Lars and Walther, Andrea and Henning, Bernd}}, issn = {{2196-7113}}, journal = {{tm - Technisches Messen}}, number = {{5}}, pages = {{294 -- 302}}, title = {{{Modelling damping in piezoceramics: A comparative study}}}, doi = {{10.1515/teme-2020-0096}}, volume = {{88}}, year = {{2021}}, } @inproceedings{22012, author = {{Claes, Leander and Feldmann, Nadine and Jurgelucks, Benjamin and Schulze, Veronika and Schmidt, Stephan and Walther, Andrea and Henning, Bernd}}, location = {{Nürnberg}}, pages = {{237--238}}, title = {{{Optimised Multi-Electrode Topology for Piezoelectric Material Characterisation}}}, doi = {{10.5162/SMSI2021/A10.1}}, year = {{2021}}, } @misc{23462, author = {{Schulze, Veronika and Schmidt, Stephan and Jurgelucks, Benjamin and Feldmann, Nadine and Claes, Leander}}, title = {{{Piezoelectric BC Modeling for Electrode Shapes with OED}}}, year = {{2021}}, } @article{33278, abstract = {{The kinetic Brownian motion on the sphere bundle of a Riemannian manifold M is a stochastic process that models a random perturbation of the geodesic flow. If M is an orientable compact constantly curved surface, we show that in the limit of infinitely large perturbation the L2-spectrum of the infinitesimal generator of a time-rescaled version of the process converges to the Laplace spectrum of the base manifold.}}, author = {{Kolb, Martin and Weich, Tobias and Wolf, Lasse}}, journal = {{Annales Henri Poincaré }}, number = {{4}}, pages = {{1283--1296}}, publisher = {{Springer Science + Business Media}}, title = {{{Spectral Asymptotics for Kinetic Brownian Motion on Surfaces of Constant Curvature}}}, volume = {{23}}, year = {{2021}}, } @inbook{33303, author = {{Herzig, Bardo and Engemann, Mario}}, booktitle = {{Fachliche Bildung und digitale Transformation - Fachdidaktische Forschung und Diskurse. Fachtagung der Gesellschaft für Fachdidaktik 2020}}, editor = {{Maurer, C. and Rincke, K. and Hemmer, M.}}, location = {{Universität Regensburg}}, pages = {{185--188}}, publisher = {{Universität }}, title = {{{Lehrerkooperation und Digitalisierung - Gestaltung digital-kooperativer Arbeitsbeziehungen von Lehrkräften und ReferendarInnen am Beispiel des Schulfachs Pädagogik}}}, doi = {{DOI: 10.25656/01:21659}}, year = {{2021}}, } @inproceedings{29938, abstract = {{Modular solid-state transformers (SSTs) are a promising technology in converting power from a 10kV three-phase medium voltage to a lower DC-voltage in the range of 100…400V to provide pure DC power to applications such as electrolyzers for hydrogen generation, data centers with a DC power distribution and DC micro grids. Modular SSTs which can be interpreted as modular multilevel converters with an isolated DC-DC output stage per module, are designed with redundant modules to increase reliability. Usually, each of the three arms operates independently, and therefore, only a fixed number of faulty modules can be compensated in each arm, even if all modules are operational in the remaining two arms. With the proposed zero-sequence voltage injection, up to 100% more faulty modules can be compensated in an arm by employing the same hardware. In addition, module power imbalances are nearly eliminated by utilizing a fundamental frequency zero-sequence voltage. A dominant 3rd harmonic zero-sequence voltage injection in combination with the 5th, 7th and several higher order harmonics with adaptive (small) amplitudes minimize the required arm voltages at steady-state. For nominal operation or symmetrical faults, the proposed technique is equivalent to the well known Min-Max voltage injection, which already reduces the peak arm voltage by 13.4% compared to a constant star point potential. A statistical analysis proves, that the expected number of tolerable faulty modules of the 1MW SST increases by 12% without the need for additional hardware.}}, author = {{Unruh, Roland and Lange, Jarren and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe)}}, isbn = {{978-9-0758-1537-5}}, keywords = {{Solid-State Transformer, Zero sequence voltage, Fault handling strategy, Power balance control technique, Three-phase system}}, location = {{Ghent, Belgium}}, publisher = {{IEEE}}, title = {{{Adaptive Zero-Sequence Voltage Injection for Modular Solid-State Transformer to Compensate for Asymmetrical Fault Conditions}}}, doi = {{https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542}}, year = {{2021}}, } @inbook{32698, author = {{Markewitz, Friedrich}}, booktitle = {{Historische Text- und Diskurssemantik. Jahrbuch für Germanistische Sprachgeschichte}}, editor = {{Bär, Jochen}}, pages = {{161--175}}, title = {{{Das historische Schulprogramm als wissenschaftssystemische Textsorte: Reflexionen zu seiner para- und peritextuellen Ausgestaltung}}}, volume = {{11}}, year = {{2021}}, } @inbook{32695, author = {{Markewitz, Friedrich}}, booktitle = {{Sprache des Todes – Sprache des Sterbens}}, editor = {{Braun, Christian}}, pages = {{121--140}}, title = {{{Aber das Getto ist grausam, es hält seine Opfer fest in seinen faulenden Zähnen“ - Zum sprachlichen Umgang mit der drohenden Vernichtung im Diskursraum des Gettos Litzmannstadt}}}, year = {{2021}}, } @inbook{32707, author = {{Markewitz, Friedrich}}, booktitle = {{Schulprogramme Höherer Lehranstalten. Interdisziplinäre Perspektiven auf eine wiederentdeckte bildungs- und kulturwissenschaftliche Quellengattung}}, editor = {{Ächtler, Norman}}, pages = {{65--88}}, title = {{{Zum programmatischen Potenzial des Schulprogramms}}}, year = {{2021}}, } @unpublished{32099, author = {{Weich, Tobias and Budde, Julia}}, booktitle = {{arXiv:2103.02968v1}}, title = {{{Wave Front Sets of Nilpotent Lie Group Representations}}}, year = {{2021}}, } @misc{24202, author = {{Pawelczyk, Sebastian and Jesinghausen, Steffen and Schmid, Hans-Joachim}}, title = {{{Charakterisierung des Fließverhaltens von Frischbeton – Entwicklung eines adaptiven Rheometers (ACCR) und Einfluss von Maßnahmen zur Sedimentationsprävention}}}, year = {{2021}}, } @article{32896, author = {{Öhlschläger, Claudia}}, journal = {{ZfdPh, Heft 2/2021}}, pages = {{221--234}}, title = {{{Wiederholung. Zu einem temporalen und ästhetischen Muster passiv erfahrener Zeit in feuilletonistischen Städtebildern Siegfried Kracauers.}}}, volume = {{140}}, year = {{2021}}, } @inbook{32055, abstract = {{Aufgrund der Einschränkungen im Rahmen der COVID-19-Pandemie sind viele Geflüchtete von Zugängen zur Aneignung der deutschen Sprache und damit von gesellschaftlicher und bildungsbezogener Teilhabe abgeschnitten. Die vorliegende Untersuchung erkundet, inwiefern das bislang präsenzbasierte Projekt Sprachbegleitung Geflüchteter pandemiebedingt auch digital vermittelte Zugänge zu Interaktions- und Sprachlerngelegenheiten schaffen und so die Auswirkungen der gesellschaftlichen und bildungsbezogenen Isolation für Geflüchtete in Gemeinschaftsunterkünften abmildern kann. Aufbauend auf einer Fragebogenuntersuchung werden dazu die Erfahrungen und Sichtweisen drei afghanischer bzw. iranischer Geflüchteter mittels episodischer Interviews elizitiert und im Rahmen einer qualitativen Inhaltsanalyse ausgewertet. Damit wird explorativ erforscht, welche Grenzen und Chancen digitaler Zugänge zu Interaktion und kommunikativer Praxis sich skizzieren lassen und welche Konsequenzen sich für die Gestaltung von Sprachlern- und Partizipationsmöglichkeiten für Geflüchtete ableiten lassen.}}, author = {{Can, Magdalena and Müller, Mareike and Niederhaus, Constanze}}, booktitle = {{Lockdown, Homeschooling und Social Distancing – der Zweitspracherwerb unter akut veränderten Bedingungen der COVID-19-Pandemie}}, editor = {{Gamper, Jana and Hövelbrinks, Britta and Schlauch, Julia}}, isbn = {{9783823384946}}, pages = {{195–222}}, publisher = {{Narr}}, title = {{{Digitale Zugänge zu kommunikativer Praxis schaffen: Eine explorative Interviewstudie im Projekt Sprachbegleitung Geflüchteter}}}, doi = {{10.24053/9783823394945}}, year = {{2021}}, } @article{26689, author = {{Goller, Michael and Caruso, Carina and Harteis, Christian}}, journal = {{International Journal of Research on Vocational and Educational Training}}, number = {{2}}, pages = {{208--223}}, title = {{{Digitalisation in agriculture: Knowledge and learning requirements of German diary farmers}}}, volume = {{8}}, year = {{2021}}, }