@article{27426, abstract = {{Regularization is used in many different areas of optimization when solutions are sought which not only minimize a given function, but also possess a certain degree of regularity. Popular applications are image denoising, sparse regression and machine learning. Since the choice of the regularization parameter is crucial but often difficult, path-following methods are used to approximate the entire regularization path, i.e., the set of all possible solutions for all regularization parameters. Due to their nature, the development of these methods requires structural results about the regularization path. The goal of this article is to derive these results for the case of a smooth objective function which is penalized by a piecewise differentiable regularization term. We do this by treating regularization as a multiobjective optimization problem. Our results suggest that even in this general case, the regularization path is piecewise smooth. Moreover, our theory allows for a classification of the nonsmooth features that occur in between smooth parts. This is demonstrated in two applications, namely support-vector machines and exact penalty methods.}}, author = {{Gebken, Bennet and Bieker, Katharina and Peitz, Sebastian}}, journal = {{Journal of Global Optimization}}, number = {{3}}, pages = {{709--741}}, title = {{{On the structure of regularization paths for piecewise differentiable regularization terms}}}, doi = {{10.1007/s10898-022-01223-2}}, volume = {{85}}, year = {{2023}}, } @article{43018, author = {{Alhaddad, Samer and Förstner, Jens and Grynko, Yevgen}}, issn = {{0022-4073}}, journal = {{Journal of Quantitative Spectroscopy and Radiative Transfer}}, keywords = {{tet_topic_scattering}}, publisher = {{Elsevier BV}}, title = {{{Numerical study of light backscattering from layers of absorbing irregular particles larger than the wavelength}}}, doi = {{10.1016/j.jqsrt.2023.108557}}, volume = {{302}}, year = {{2023}}, } @inproceedings{31849, author = {{Hoffmann, Max and Biehler, Rolf}}, booktitle = {{Proceedings of the Fourth Conference of the International Network for Didactic Research in University Mathematics (INDRUM 2022, 19-22 October 2022)}}, editor = {{Trigueros, Marı́a and Barquero, Berta and Hochmuth, Reinhard and Peters, Jana}}, keywords = {{Teaching and learning of specific topics in university mathematics, Transition to, across and from university mathematics, Student Teachers, Geometry, Congruence, Double Discontinuity.}}, publisher = {{University of Hannover and INDRUM.}}, title = {{{Student Teachers ’ Knowledge of Congruence before a University Course on Geometry}}}, year = {{2023}}, } @inproceedings{43097, author = {{Florensa, Ignasio and Hoffmann, Max and Romo Vázquez, Avenilde and Zandieh, Michelle and Martínez-Planell, Rafael}}, booktitle = {{Proceedings of the Fourth Conference of the International Network for Didactic Research in University Mathematics (INDRUM 2022, 19-22 October 2022)}}, editor = {{Trigueros, Marı́a and Barquero, Berta and Hochmuth, Reinhard and Peters, Jana}}, title = {{{Innovations in university teaching based on mathematic education research}}}, year = {{2023}}, } @misc{43186, author = {{Süßmann, Johannes}}, title = {{{Pantheon}}}, year = {{2023}}, } @article{43464, abstract = {{Lightweight design is a common approach to reduce energy demand in the use stage of vehicles. The production of lightweight materials is usually associated with an increase in energy demand, so the environmental impacts of lightweight structures need to be assessed holistically using a life cycle assessment. To estimate the life cycle environmental impacts of a product in its developmental stage, for example, by life cycle engineering, future changes in relevant influencing factors must be considered. Prospective life cycle assessment provides methods for integrating future scenarios into life cycle assessment studies. However, approaches for integrating prospective life cycle assessment into product development are limited. The objective of this work is to provide the methodological foundation for integrating future scenarios of relevant influencing factors in the development of lightweight structures. The applicability of the novel methodology is demonstrated by a case study of a structural component in a steel, aluminium, and hybrid design. The results show that appropriate decarbonisation measures can reduce the life cycle greenhouse gas emissions by up to 95 percent until 2050. We also found that shifts in the environmentally optimal design are possible in future scenarios. Therefore, the methodology and data provided contribute to improved decision-making in product development.}}, author = {{Ostermann, Moritz and Grenz, Julian and Triebus, Marcel and Cerdas, Felipe and Marten, Thorsten and Tröster, Thomas and Herrmann, Christoph}}, issn = {{1996-1073}}, journal = {{Energies}}, keywords = {{Life Cycle Engineering, Life Cycle Assessment, Lightweight Design, Prospective LCA, Future-oriented LCA, Energy System, Material production, Sustainable production}}, number = {{8}}, publisher = {{MDPI AG}}, title = {{{Integrating Prospective Scenarios in Life Cycle Engineering: Case Study of Lightweight Structures}}}, doi = {{10.3390/en16083371}}, volume = {{16}}, year = {{2023}}, } @article{44058, abstract = {{A relatively small body of research has been conducted on the near- and long-term effects of study abroad (SA) to date. This existing research suggests that SA effects on language skills tend to be volatile, while the impact on various aspects of learners’ personal, academic, and professional development may be longer-lasting. Yet, learner perspectives on the dynamics and durability of such effects, in particular in the context of short-term SA programs, remain largely unexplored. This study hence investigates the near-term impact of short-term SA programs as experienced by students within the first months and years following their sojourns. A qualitative case-study design is employed to examine the accounts of four American students of German, who studied abroad in Austria for four weeks and were interviewed repeatedly over a period of up to 40 months after their sojourns. The results suggest that, from the students’ perspective, many effects deteriorate in the near term, although the overall sojourn experience still appears influential. Abstract in German Nur wenige Forschungsvorhaben haben sich bislang den mittel- bis langfristigen Auswirkungen studentischer Auslandsaufenthalte gewidmet; die bisherige Datenlage deutet jedoch darauf hin, dass die Auswirkungen auf sprachliche Kompetenzen eher unbeständig sind, wohingegen die persönliche, studiums- und berufsbezogene Entwicklung der Lernenden länger von einem Auslandsaufenthalt beeinflusst wird. Die Dynamik und Beständigkeit derartiger Auswirkungen wurden jedoch kaum mit Blick auf kurze Auslandsaufenthalte (≤ acht Wochen) sowie aus der Perspektive der Studierenden erforscht, was die vorliegende Studie insbesondere hinsichtlich mittelfristiger Effekte fokussiert. Mittels eines qualitativen Fallstudiendesigns werden die Interviewdaten vier amerikanischer Deutschlernender untersucht, die sich vier Wochen in Österreich aufhielten und in einem Zeitraum von bis zu 40 Monaten nach ihrem Aufenthalt wiederholt befragt wurden. Die Ergebnisse zeigen, dass viele Auswirkungen eines solchen Aufenthalts aus studentischer Perspektive mittelfristig verblassen, auch wenn der Auslandsaufenthalt im Gesamten weiterhin als einflussreiche Erfahrung wahrgenommen wird.}}, author = {{Müller, Mareike}}, issn = {{2380-8144}}, journal = {{Frontiers: The Interdisciplinary Journal of Study Abroad}}, number = {{1}}, pages = {{275--304}}, publisher = {{The Forum on Education Abroad}}, title = {{{Near-Term Effects of Short-Term Study Abroad: A Longitudinal Examination of Learner Perceptions}}}, doi = {{10.36366/frontiers.v35i1.684}}, volume = {{35}}, year = {{2023}}, } @article{42252, abstract = {{Die Wirtschaftlichkeit von Wärmemotoren wird maßgeblich durch die Rückführung von Wärme in Rekuperatoren beeinflusst. Beim isobaren Expansionsmotor vom Bush-Typ, einem Wärmemotor, welcher bereits mit Wärmequellen ab 60°C betrieben werden kann, steigt der thermische Wirkungsgrad durch den Einsatz von Rekuperatoren signifikant. Gleichzeitig wirken sich das Fluidvolumen des Wärmeübertragers sowie der beim Betrieb auftretende Druckverlust negativ auf den thermischen Wirkungsrad aus. In dieser Arbeit wird der Zusammenhang von Totvolumen, Druckverlust und Wärmerückgewinnung untersucht und Empfehlungen für den Betrieb von Rekuperatoren am isobaren Expansionsmotor gegeben.}}, author = {{Mügge, Nils and Kronberg, Alexander and Glushenkov, Maxim and Kenig, Eugeny Y.}}, journal = {{Chemie Ingenieur Technik}}, keywords = {{Isobarer Expansionsmotor, Dynamische Wärmeübertragungsmodellierung, Phasenwechsel, dichte Arbeitsmedien}}, number = {{5}}, publisher = {{Wiley}}, title = {{{Untersuchung überlagerter Effekte von Druckverlust und Totvolumen durch Rekuperation am isobaren Expansionsmotor}}}, doi = {{10.1002/cite.202200243}}, volume = {{95}}, year = {{2023}}, } @article{36983, abstract = {{AbstractThe use of structured measuring systems to prevent wall slip is a common approach to obtain absolute rheological values. Typically, only the minimum distance between the measuring surfaces is used for further calculation, implying that no flow occurs between the structural elements. But this assumption is misleading, and a gap correction is necessary. To determine the radius correction $$\Delta r$$ Δ r for specific geometries, we conducted investigations on three Newtonian fluids (two silicon oils and one suspension considered to be Newtonian in the relevant shear rate range). The results show that $$\Delta r$$ Δ r is not only shear- and material-independent, but geometry-dependent, providing a Newtonian flow behaviour in a similar viscosity range. Therefore, a correction value can be determined with only minute deviations in different Newtonian fluids. As the conducted laboratory measurements are very time-consuming and expensive, a CFD-approach with only very small deviations was additionally developed and compared for validation purposes. Therefore, simulation is an effective and resource-efficient alternative to the presented laboratory measurements to determine $$\Delta r$$ Δ r for the correction of structured coaxial geometries even for non-Newtonian fluids in the future.}}, author = {{Josch, Sebastian and Jesinghausen, Steffen and Dechert, Christopher and Schmid, Hans-Joachim}}, issn = {{0035-4511}}, journal = {{Rheologica Acta}}, keywords = {{rheology, rheometry, suspension, coaxial, correction}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Experimental and simulative determination and correction of the effective gap extension in structured coaxial measuring systems}}}, doi = {{10.1007/s00397-023-01383-2}}, year = {{2023}}, } @inproceedings{30125, abstract = {{We present an approach for guaranteed constraint satisfaction by means of data-based optimal control, where the model is unknown and has to be obtained from measurement data. To this end, we utilize the Koopman framework and an eDMD-based bilinear surrogate modeling approach for control systems to show an error bound on predicted observables, i.e., functions of the state. This result is then applied to the constraints of the optimal control problem to show that satisfaction of tightened constraints in the purely data-based surrogate model implies constraint satisfaction for the original system.}}, author = {{Schaller, Manuel and Worthmann, Karl and Philipp, Friedrich and Peitz, Sebastian and Nüske, Feliks}}, booktitle = {{IFAC-PapersOnLine}}, number = {{1}}, pages = {{169--174}}, title = {{{Towards reliable data-based optimal and predictive control using extended DMD}}}, doi = {{10.1016/j.ifacol.2023.02.029}}, volume = {{56}}, year = {{2023}}, } @article{43094, abstract = {{}}, author = {{Heck, Tamara and Steinhardt, Isabel and Rahal, Rima-Maria and Schubotz, Moritz and Scholl, Dominik and Behrens, Sarah}}, issn = {{2367-7163}}, journal = {{Research Ideas and Outcomes}}, keywords = {{Open Science}}, publisher = {{Pensoft Publishers}}, title = {{{Bootstrapping the Open Science culture: The fellowship approach}}}, doi = {{10.3897/rio.9.e103675}}, volume = {{9}}, year = {{2023}}, } @proceedings{35062, editor = {{Meine, Sabine and Otto, Arnold and Süßmann, Johannes}}, isbn = {{978-3-8260-7218-5}}, publisher = {{Königshausen & Neumann}}, title = {{{Musiklandschaften zwischen Rhein und Weser. Pluralisierung und Verflechtung entlang des Hellwegs in der Frühen Neuzeit. Unter Mitarbeit v. Markus Lauert}}}, doi = {{https://doi.org/10.36202/9783826077920}}, volume = {{13}}, year = {{2023}}, } @article{43245, abstract = {{High-contrast slab waveguide Bragg gratings with 1D periodicity are investigated. For specific oblique excitation by semi-guided waves at sufficiently high angles of incidence, the idealized structures do not exhibit any radiative losses, such that reflectance and transmittance for the single port mode add strictly up to one. We consider a series of symmetric, fully and partly etched finite gratings, for parameters found in integrated silicon photonics. These can act as spectral filters with a reasonably flattop response. Apodization can lead to more box shaped reflectance and transmittance spectra. Together with a narrowband Fabry–Perot filter, these configurations are characterized by reflection bands, or transmittance peaks, with widths that span three orders of magnitude.}}, author = {{Hammer, Manfred and Farheen, Henna and Förstner, Jens}}, issn = {{0740-3224}}, journal = {{Journal of the Optical Society of America B}}, keywords = {{tet_topic_waveguide}}, number = {{4}}, pages = {{862}}, publisher = {{Optica Publishing Group}}, title = {{{How to suppress radiative losses in high-contrast integrated Bragg gratings}}}, doi = {{10.1364/josab.485725}}, volume = {{40}}, year = {{2023}}, } @unpublished{43132, author = {{Meier, Torsten and Grisard, S. and Trifonov, A.V. and Rose, Hendrik and Reichhardt, R. and Reichelt, Matthias and Schneider, C. and Kamp, M. and Höfling, S. and Bayer, M. and Akimov, I.A}}, booktitle = {{arxiv:2302.02480}}, title = {{{Temporal sorting of optical multi-wave-mixing processes in semiconductor quantum dots}}}, year = {{2023}}, } @article{44097, abstract = {{We present strong enhancement of third harmonic generation in an amorphous silicon metasurface consisting of elliptical nano resonators. We show that this enhancement originates from a new type of multi-mode Fano mechanism. These ‘Super-Fano’ resonances are investigated numerically in great detail using full-wave simulations. The theoretically predicted behavior of the metasurface is experimentally verified by linear and nonlinear transmission spectroscopy. Moreover, quantitative nonlinear measurements are performed, in which an absolute conversion efficiency as high as ηmax ≈ 2.8 × 10−7 a peak power intensity of 1.2 GW cm−2 is found. Compared to an unpatterned silicon film of the same thickness amplification factors of up to ~900 are demonstrated. Our results pave the way to exploiting a strong Fano-type multi-mode coupling in metasurfaces for high THG in potential applications.}}, author = {{Hähnel, David and Golla, Christian and Albert, Maximilian and Zentgraf, Thomas and Myroshnychenko, Viktor and Förstner, Jens and Meier, Cedrik}}, issn = {{2047-7538}}, journal = {{Light: Science & Applications}}, keywords = {{tet_topic_meta}}, number = {{1}}, pages = {{97}}, publisher = {{Springer Nature}}, title = {{{A multi-mode super-fano mechanism for enhanced third harmonic generation in silicon metasurfaces}}}, doi = {{https://doi.org/10.1038/s41377-023-01134-1}}, volume = {{12}}, year = {{2023}}, } @book{44083, author = {{Bauer, Anna Brigitte}}, isbn = {{978-3-8325-5625-9}}, publisher = {{Logos Verlag Berlin GmbH}}, title = {{{Experimentelle Kompetenz Physikstudierender. Entwicklung und erste Erprobung eines performanzorientierten Kompetenzstrukturmodells unter Nutzung qualitativer Methoden}}}, doi = {{10.30819/5625}}, volume = {{352}}, year = {{2023}}, } @misc{43374, author = {{Schürmann, Patrick}}, title = {{{ A Formal Comparison of Advanced Digital Signature Primitives}}}, year = {{2023}}, } @article{42515, abstract = {{ Microcellular wood fiber reinforced polymers offer the possibility to reduce the use of fossil raw materials. In particular, thick-walled structures with thicknesses greater than 6 mm offer a high potential for weight savings. This study investigates the cell structures and mechanical properties of injection-molded test specimens. The influence of different thicknesses (6–10 mm) along with different chemical blowing agents (endothermic, exothermic) with varying dosages (0–2 wt%) is analyzed. The investigations reveal that exothermic chemical blowing agents form finer cells consistently to thin-walled structures than endothermic ones. Higher foaming agent content leads to higher pore fractions, with many small cells coalescing into a large open-pore cell network. The mechanical properties depend mainly on the pore content of the sample. The specific tensile properties deteriorate with the use of chemical blowing agents (CFA), whereas the sandwich structure produced with compact edge layers has a positive influence on the specific flexural properties. }}, author = {{Moritzer, Elmar and Flachmann, Felix}}, issn = {{0021-955X}}, journal = {{Journal of Cellular Plastics}}, keywords = {{Materials Chemistry, Polymers and Plastics, General Chemistry}}, number = {{3}}, pages = {{187--199}}, publisher = {{SAGE Publications}}, title = {{{Morphological and mechanical properties of foamed thick-walled Wood-Plastic-Composite structures}}}, doi = {{10.1177/0021955x231161175}}, volume = {{59}}, year = {{2023}}, } @article{42179, author = {{Burmeister, Sascha Christian and Schryen, Guido}}, journal = {{Energy Systems}}, publisher = {{Springer}}, title = {{{Distribution Network Optimization: Predicting computation times to design scenario analysis for network operators}}}, doi = {{10.1007/s12667-023-00572-5}}, year = {{2023}}, } @article{43034, abstract = {{Abstract The accessibility to rheological parameters for concrete is becoming more and more relevant. This is mainly related to the constantly emerging challenges, such as not only the development of high-strength concretes is progressing very fast but also the simulation of the flow behaviour is of high importance. The main problem, however, is that the rheological characterisation of fresh concrete is not possible via commercial rheometers. The so-called concrete rheometers provide valuable relative values for comparing different concretes, but they cannot measure absolute values. Therefore, we developed an adaptive coaxial concrete rheometer (ACCR) that allows the measurement of fresh concrete with particles up to d max = 5.5 mm {d}_{{\rm{\max }}}=5.5\hspace{.5em}{\rm{mm}} . The comparison of the ACCR with a commercial rheometer showed very good agreement for selected test materials (Newtonian fluid, shear thinning fluid, suspension, and yield stress fluid), so that self-compacting concrete was subsequently measured. Since these measurements showed a very high reproducibility, the rheological properties of the fresh concrete could be determined with high accuracy. The common flow models (Bingham (B), Herschel–Bulkley, modified Bingham (MB) models) were also tested for their applicability, with the Bingham and the modified Bingham model proving to be the best suitable ones.}}, author = {{Josch, Sebastian and Jesinghausen, Steffen and Schmid, Hans-Joachim}}, issn = {{1617-8106}}, journal = {{Applied Rheology}}, keywords = {{Condensed Matter Physics, General Materials Science}}, number = {{1}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Development of an adaptive coaxial concrete rheometer and rheological characterisation of fresh concrete}}}, doi = {{10.1515/arh-2022-0140}}, volume = {{33}}, year = {{2023}}, } @inbook{44249, abstract = {{State education in honest tax payment can be understood as a facet of training in citizenship, i.e. as an attempt by the modern state to standardize the behavior of its citizens and to prevent deviations. Based on this Foucauldian understanding, this exploratory article examines tax education in the United States, Spain, and West Germany from the mid-1940s to the late 1980s. During this period, the USA asserted itself as the champion of tax education and Spain consistently tried to emulate this example, albeit with more modest means and different semantic strategies from as early as the 1960s, when it was still under a autoritarian regime. The FRG, however, completely discontinued its few early attempts at tax education from the mid-1950s onwards. Even during the economic crises and tax scandals of the 1970s, there was no relaunch of the programs. The article locates the reasons for this highly uneven development in the different ideal images of the citizen in the three states.}}, author = {{Schönhärl, Korinna and Düll, Nasrin and Ramírez Lugo , Nadya Melina}}, booktitle = {{Tax Evasion and Tax Havens since the Nineteenth Century }}, editor = {{Sébastien, Guex and Hadrien, Buclin}}, pages = {{355--376}}, publisher = {{Springer}}, title = {{{Tax Education After WWII: How Spain, the USA, and West Germany Tried to Make Their Citizens Pay Honestly}}}, year = {{2023}}, } @article{44321, author = {{Neumann, Phillip}}, issn = {{0513-9066}}, journal = {{Zeitschrift für Heilpädagogik}}, keywords = {{Inklusion, Sonderpädagogik, Bildung, Bildungsstudien, Integration}}, number = {{5}}, pages = {{230--232}}, title = {{{Studien zu Schulleistungen und ihre Aufbereitung}}}, volume = {{74}}, year = {{2023}}, } @inbook{35063, author = {{Meine, Sabine and Otto, Arnold and Süßmann, Johannes}}, booktitle = {{Musiklandschaften zwischen Rhein und Weser. Pluralisierung und Verflechtung entlang des Hellwegs in der Frühen Neuzeit. Unter Mitarbeit v. Markus Lauert}}, isbn = {{978-3-8260-7218-5}}, pages = {{7–42}}, publisher = {{Königshausen & Neumann}}, title = {{{Musiklandschaften zwischen Rhein und Weser – Einführung}}}, doi = {{https://doi.org/10.36202/9783826077920}}, year = {{2023}}, } @inproceedings{20841, author = {{Gharibian, Sevag and Watson, James and Bausch, Johannes}}, booktitle = {{Proceedings of the 40th International Symposium on Theoretical Aspects of Computer Science (STACS)}}, pages = {{54:1--54:21}}, title = {{{The Complexity of Translationally Invariant Problems beyond Ground State Energies}}}, doi = {{https://doi.org/10.4230/LIPIcs.STACS.2023.54}}, volume = {{254}}, year = {{2023}}, } @unpublished{44512, abstract = {{For open world applications, deep neural networks (DNNs) need to be aware of previously unseen data and adaptable to evolving environments. Furthermore, it is desirable to detect and learn novel classes which are not included in the DNNs underlying set of semantic classes in an unsupervised fashion. The method proposed in this article builds upon anomaly detection to retrieve out-of-distribution (OoD) data as candidates for new classes. We thereafter extend the DNN by $k$ empty classes and fine-tune it on the OoD data samples. To this end, we introduce two loss functions, which 1) entice the DNN to assign OoD samples to the empty classes and 2) to minimize the inner-class feature distances between them. Thus, instead of ground truth which contains labels for the different novel classes, the DNN obtains a single OoD label together with a distance matrix, which is computed in advance. We perform several experiments for image classification and semantic segmentation, which demonstrate that a DNN can extend its own semantic space by multiple classes without having access to ground truth.}}, author = {{Uhlemeyer, Svenja and Lienen, Julian and Hüllermeier, Eyke and Gottschalk, Hanno}}, booktitle = {{arXiv:2305.00983}}, title = {{{Detecting Novelties with Empty Classes}}}, year = {{2023}}, } @article{44672, abstract = {{With enhancing digitalization, condition monitoring is used in an increasing number of application fields across various industrial sectors. By its application, increased reliability as well as reduced risks and costs can be achieved. Based on different approaches, technical systems are monitored and measured data is analyzed to enable condition-based or predictive maintenance. To this end, machine learning approaches are usually implemented to diagnose the health states or predict the health index of the monitored system. However, these trained models are often black-box models, not intuitively explainable for a human. To overcome this shortcoming, a model-based approach based on physics is developed for piezoelectric bending actuators. Such a model enables a transparent representation of the system. Moreover, the model-based approach is extended by a parameter-estimation to account for sudden changes in behavior e. g. caused by occurring cracks.}}, author = {{Bender, Amelie}}, issn = {{0924-4247}}, journal = {{Sensors and Actuators A: Physical}}, keywords = {{Condition Monitoring, Model-based approach Diagnostics, Varying conditions, Explainability, Piezoelectric bending actuators}}, publisher = {{Elsevier BV}}, title = {{{Model-based condition monitoring of piezoelectric bending actuators}}}, doi = {{10.1016/j.sna.2023.114399}}, volume = {{357}}, year = {{2023}}, } @inproceedings{44194, author = {{Ahmed, Qazi Arbab and Awais, Muhammad and Platzner, Marco}}, booktitle = {{The 24th International Symposium on Quality Electronic Design (ISQED'23), San Francisco, Califorina USA}}, location = {{San Fransico CA 94023-0607, USA}}, title = {{{MAAS: Hiding Trojans in Approximate Circuits}}}, year = {{2023}}, } @article{44044, abstract = {{Dispersion is present in every optical setup and is often an undesired effect, especially in nonlinear-optical experiments where ultrashort laser pulses are needed. Typically, bulky pulse compressors consisting of gratings or prisms are used to address this issue by precompensating the dispersion of the optical components. However, these devices are only able to compensate for a part of the dispersion (second-order dispersion). Here, we present a compact pulse-shaping device that uses plasmonic metasurfaces to apply an arbitrarily designed spectral phase delay allowing for a full dispersion control. Furthermore, with specific phase encodings, this device can be used to temporally reshape the incident laser pulses into more complex pulse forms such as a double pulse. We verify the performance of our device by using an SHG-FROG measurement setup together with a retrieval algorithm to extract the dispersion that our device applies to an incident laser pulse.}}, author = {{Geromel, René and Georgi, Philip and Protte, Maximilian and Lei, Shiwei and Bartley, Tim and Huang, Lingling and Zentgraf, Thomas}}, issn = {{1530-6984}}, journal = {{Nano Letters}}, keywords = {{Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering}}, number = {{8}}, pages = {{3196 -- 3201}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Compact Metasurface-Based Optical Pulse-Shaping Device}}}, doi = {{10.1021/acs.nanolett.2c04980}}, volume = {{23}}, year = {{2023}}, } @article{44837, abstract = {{Hydrothermal carbonization (HTC) is an efficient thermochemical method for the conversion of organic feedstock to carbonaceous solids. HTC of different saccharides is known to produce microspheres (MS) with mostly Gaussian size distribution, which are utilized as functional materials in various applications, both as pristine MS and as a precursor for hard carbon MS. Although the average size of the MS can be influenced by adjusting the process parameters, there is no reliable mechanism to affect their size distribution. Our results demonstrate that HTC of trehalose, in contrast to other saccharides, results in a distinctly bimodal sphere diameter distribution consisting of small spheres with diameters of (2.1 ± 0.2) μm and of large spheres with diameters of (10.4 ± 2.6) μm. Remarkably, after pyrolytic post-carbonization at 1000 °C the MS develop a multimodal pore size distribution with abundant macropores > 100 nm, mesopores > 10 nm and micropores < 2 nm, which were examined by small-angle X-ray scattering and visualized by charge-compensated helium ion microscopy. The bimodal size distribution and hierarchical porosity provide an extraordinary set of properties and potential variables for the tailored synthesis of hierarchical porous carbons, making trehalose-derived hard carbon MS a highly promising material for applications in catalysis, filtration, and energy storage devices.}}, author = {{Wortmann, Martin and Keil, Waldemar and Diestelhorst, Elise and Westphal, Michael and Haverkamp, René and Brockhagen, Bennet and Biedinger, Jan and Bondzio, Laila and Weinberger, Christian and Baier, Dominik and Tiemann, Michael and Hütten, Andreas and Hellweg, Thomas and Reiss, Günter and Schmidt, Claudia and Sattler, Klaus and Frese, Natalie}}, issn = {{2046-2069}}, journal = {{RSC Advances}}, keywords = {{General Chemical Engineering, General Chemistry}}, number = {{21}}, pages = {{14181--14189}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Hard carbon microspheres with bimodal size distribution and hierarchical porosity via hydrothermal carbonization of trehalose}}}, doi = {{10.1039/d3ra01301d}}, volume = {{13}}, year = {{2023}}, } @inproceedings{45205, author = {{Dreiling, Dmitrij and Itner, Dominik and Hetkämper, Tim and Birk, Carolin and Gravenkamp, Hauke and Henning, Bernd}}, booktitle = {{SMSI 2023 Conference}}, isbn = {{978-3-9819376-8-8}}, location = {{Nürnberg}}, pages = {{394 -- 395}}, publisher = {{AMA Association For Sensors And Measurement}}, title = {{{Improved determination of viscoelastic material parameters using a pulse-echo measurement setup}}}, doi = {{10.5162/SMSI2023/P59}}, year = {{2023}}, } @misc{43375, author = {{Koch, Angelina}}, title = {{{Privacy-Preserving Collection and Evaluation of Log Files}}}, year = {{2023}}, } @article{44361, author = {{Schryen, Guido and Sperling, Martina}}, journal = {{Computers & Operations Research}}, number = {{September}}, title = {{{Literature Reviews in Operations Research: A New Taxonomy and a Meta Review}}}, volume = {{157}}, year = {{2023}}, } @article{45596, abstract = {{Dielectric metasurfaces provide a unique platform for efficient harmonic generation and optical wavefront manipulation at the nanoscale. Tailoring phase and amplitude of a nonlinearly generated wave with a high emission efficiency using resonance-based metasurfaces is a challenging task that often requires state-of-the-art numerical methods. Here, we propose a simple yet effective approach combining a sampling method with a Monte Carlo approach to design the third-harmonic wavefront generated by all-dielectric metasurfaces composed of elliptical silicon nanodisks. Using this approach, we theoretically demonstrate the full nonlinear 2π phase control with a uniform and highest possible amplitude in the considered parameter space, allowing us to design metasurfaces operating as third harmonic beam deflectors capable of steering light into a desired direction with high emission efficiency. The TH beam deflection with a record calculated average conversion efficiency of 1.2 × 10–1 W–2 is achieved. We anticipate that the proposed approach will be widely applied as alternative to commonly used optimization algorithms with higher complexity and implementation effort for the design of metasurfaces with other holographic functionalities.}}, author = {{Hähnel, David and Förstner, Jens and Myroshnychenko, Viktor}}, issn = {{2330-4022}}, journal = {{ACS Photonics}}, keywords = {{tet_topic_meta}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Efficient Modeling and Tailoring of Nonlinear Wavefronts in Dielectric Metasurfaces}}}, doi = {{10.1021/acsphotonics.2c01967}}, year = {{2023}}, } @inbook{45606, author = {{Freymuth, Nina}}, booktitle = {{Diskriminierungsprozesse und Teilhabeperspektiven - Herausforderungen für die Praxis der Inklusion. Ausgewählte Master-Thesen 2018-2022 des Masterstudiengangs "Soziale Inklusion: Gesundheit und Bildung" der Evangelischen Hochschule Rheinland-Westfalen-Lippe}}, editor = {{Balz, HHans-Jürgen and Huneke, Annika and Kuhlmann, Carola and Römisch, Kathrin}}, pages = {{22--33}}, title = {{{Alternative für alle? Inklusionsspezifische Analyse der AfD und ihrer Wähler*innen}}}, year = {{2023}}, } @article{44383, author = {{Dieter, Peter and Caron, Matthew and Schryen, Guido}}, journal = {{European Journal of Operational Research (EJOR)}}, number = {{1}}, pages = {{283--300}}, title = {{{Integrating driver behavior into last-mile delivery routing: Combining machine learning and optimization in a hybrid decision support framework}}}, doi = {{https://doi.org/10.1016/j.ejor.2023.04.043}}, volume = {{311}}, year = {{2023}}, } @article{45672, author = {{Meier, Jana and Janzen, Thomas and Wotschel, Philipp and Vogelsang, Christoph}}, journal = {{die hochschullehre}}, publisher = {{wbv}}, title = {{{Rollenspielbasierte Simulationen als Übungs- und Prüfungsformate im Lehramtsstudium. Eine explorative Studie zu Erfahrungen und Einschätzungen aus Studierendensicht.}}}, doi = {{10.3278/HSL2307W}}, volume = {{9}}, year = {{2023}}, } @inproceedings{45695, author = {{Hotegni, Sedjro Salomon and Mahabadi, Sepideh and Vakilian, Ali}}, booktitle = {{Proceedings of the 40th International Conference on Machine Learning, Honolulu, Hawaii, USA. PMLR 202, 2023.}}, keywords = {{Fair range clustering}}, location = {{Honolulu, Hawaii, USA}}, title = {{{Approximation Algorithms for Fair Range Clustering}}}, year = {{2023}}, } @inproceedings{43060, author = {{Hebrok, Sven Niclas and Nachtigall, Simon and Maehren, Marcel and Erinola, Nurullah and Merget, Robert and Somorovsky, Juraj and Schwenk, Jörg}}, booktitle = {{32nd USENIX Security Symposium}}, title = {{{We Really Need to Talk About Session Tickets: A Large-Scale Analysis of Cryptographic Dangers with TLS Session Tickets}}}, year = {{2023}}, } @article{44116, abstract = {{Faradaic reactions including charge transfer are often accompanied with diffusion limitation inside the bulk. Conductive two-dimensional frameworks (2D MOFs) with a fast ion transport can combine both - charge transfer and fast diffusion inside their porous structure. To study remaining diffusion limitations caused by particle morphology, different synthesis routes of Cu-2,3,6,7,10,11-hexahydroxytriphenylene (Cu3(HHTP)2), a copper-based 2D MOF, are used to obtain flake- and rod-like MOF particles. Both morphologies are systematically characterized and evaluated for redox-active Li+ ion storage. The redox mechanism is investigated by means of X-ray absorption spectroscopy, FTIR spectroscopy and in situ XRD. Both types are compared regarding kinetic properties for Li+ ion storage via cyclic voltammetry and impedance spectroscopy. A significant influence of particle morphology for 2D MOFs on kinetic aspects of electrochemical Li+ ion storage can be observed. This study opens the path for optimization of redox active porous structures to overcome diffusion limitations of Faradaic processes.}}, author = {{Wrogemann, Jens Matthies and Lüther, Marco Joes and Bärmann, Peer and Lounasvuori, Mailis and Javed, Ali and Tiemann, Michael and Golnak, Ronny and Xiao, Jie and Petit, Tristan and Placke, Tobias and Winter, Martin}}, issn = {{1433-7851}}, journal = {{Angewandte Chemie International Edition}}, keywords = {{General Chemistry, Catalysis}}, number = {{26}}, pages = {{e202303111}}, publisher = {{Wiley}}, title = {{{Overcoming Diffusion Limitation of Faradaic Processes: Property‐Performance Relationships of 2D Conductive Metal‐Organic Framework Cu3(HHTP)2 for Reversible Lithium‐Ion Storage}}}, doi = {{10.1002/anie.202303111}}, volume = {{62}}, year = {{2023}}, } @misc{36842, booktitle = {{Navigationen - Zeitschrift für Medien- und Kulturwissenschaften}}, editor = {{Eckel, Julia and Ernst, Christoph and Schröter, Jens}}, issn = {{1619-1641}}, keywords = {{tech demo, technology demonstration, demo or die}}, number = {{1}}, title = {{{Navigationen: Tech | Demo}}}, volume = {{23}}, year = {{2023}}, } @inproceedings{45759, author = {{Abbas, Nilab and Bauer, Anna Brigitte and Reinhold, Peter}}, booktitle = {{Lernen, Lehren und Forschen in einer digital geprägten Welt}}, editor = {{van Vorst, Helena}}, location = {{Aachen 2023}}, title = {{{PSΦ: Entwicklung von Unterstützungsmaßnahmen für Theoretische Physik}}}, year = {{2023}}, } @inproceedings{45758, author = {{Bauer, Anna Brigitte and Reinhold, Peter}}, booktitle = {{Lernen, Lehren und Forschen in einer digital geprägten Welt}}, editor = {{van Vorst, Helena}}, location = {{Aachen 2022}}, title = {{{PSФ: Entwicklung einer abgestimmten Studieneingangsphase (Physik) }}}, year = {{2023}}, } @article{43827, abstract = {{A series of new organic donor–π–acceptor dyes incorporating a diquat moiety as a novel electron-acceptor unit have been synthesized and characterized. The analytical data were supported by DFT calculations. These dyes were explored in the aerobic thiocyanation of indoles and pyrroles. Here they showed a high photocatalytic activity under visible light, giving isolated yields of up to 97 %. In addition, the photocatalytic activity of standalone diquat and methyl viologen through formation of an electron donor acceptor complex is presented.}}, author = {{Meier, Armin and Badalov, Sabuhi and Biktagirov, Timur and Schmidt, Wolf Gero and Wilhelm, René}}, issn = {{0947-6539}}, journal = {{Chemistry – A European Journal}}, keywords = {{General Chemistry, Catalysis, Organic Chemistry}}, number = {{22}}, pages = {{ e202203541}}, publisher = {{Wiley}}, title = {{{Diquat Based Dyes: A New Class of Photoredox Catalysts and Their Use in Aerobic Thiocyanation}}}, doi = {{10.1002/chem.202203541}}, volume = {{ 29}}, year = {{2023}}, } @article{45764, abstract = {{As a benchmark, the structural, electronic and optical properties of the three main phases of TiO$\rm{_2}$ crystals have been calculated using Hubbard U correction and hybrid functional methods in density-functional theory. These calculations are compared concerning the available experimental observations on pristine TiO$\rm{_2}$ crystals. Modified hybrid functionals, particularly the PBE0 functional with 11.4% fraction of exact exchange, are shown to provide highly accurate atomic structures and also accurate electronic structure data, including optical excitation energies. With $\rm{DFT+U}$, accurate optical spectra are also possible, but only if the Hubbard U is applied on the O $\rm2p$ electrons exclusively. Furthermore, both methods, the 11.4%-PBE0 hybrid functional and the $\rm{DFT+U_p}$ scheme have been used to study TiO$\rm{_2}$ amorphous ultra-thin films, confirming the agreement of the two methods even with respect to small details of the optical spectra. Our results show that the proposed $\rm{DFT+U_p}$ methodology is computationally efficient, but still accurate. It can be applied to well-ordered TiO$\rm{_2}$ polymorphs as well as to amorphous TiO$\rm{_2}$ and will allow for the calculations of complex titania-based structures.}}, author = {{Badalov, Sabuhi and Bocchini, Adriana and Wilhelm, Rene and Kozub, A. L. and Gerstmann, Uwe and Schmidt, Wolf Gero}}, journal = {{Materials Research Express}}, publisher = {{IOP Publishing}}, title = {{{Rutile, anatase, brookite and titania thin film from Hubbard corrected and hybrid DFT}}}, doi = {{10.1088/2053-1591/ace0fa}}, year = {{2023}}, } @article{45782, abstract = {{The development of automotive components with reduced greenhouse gas (GHG) emissions is needed to reduce overall vehicle emissions. Life Cycle Engineering (LCE) based on Life Cycle Assessment (LCA) supports this by providing holistic information and improvement potentials regarding eco-efficient products. Key factors influencing LCAs of automotive components, such as material production, will change in the future. First approaches for integrating future scenarios for these key factors into LCE already exist, but they only consider a limited number of parameters and scenarios. This work aims to develop a method that can be practically applied in the industry for integrating prospective LCAs (pLCA) into the LCE of automotive components, considering relevant parameters and consistent scenarios. Therefore, pLCA methods are further developed to investigate the influence of future scenarios on the GHG emissions of automotive components. The practical application is demonstrated for a vehicle component with different design options. This paper shows that different development paths of the foreground and background system can shift the ecological optimum of design alternatives. Therefore, future pathways of relevant parameters must be considered comprehensively to reduce GHG emissions of future vehicles. This work contributes to the methodological and practical integration of pLCA into automotive development processes and provides quantitative results.}}, author = {{Grenz, Julian and Ostermann, Moritz and Käsewieter, Karoline and Cerdas, Felipe and Marten, Thorsten and Herrmann, Christoph and Tröster, Thomas}}, issn = {{2071-1050}}, journal = {{Sustainability}}, keywords = {{prospective LCA, life cycle engineering (LCE), lightweight design, automotive components, body parts, circular economy, steel, aluminum, hybrid materials, fiber metal laminates}}, number = {{13}}, publisher = {{MDPI AG}}, title = {{{Integrating Prospective LCA in the Development of Automotive Components}}}, doi = {{10.3390/su151310041}}, volume = {{15}}, year = {{2023}}, } @inproceedings{31880, abstract = {{The notion of neural collapse refers to several emergent phenomena that have been empirically observed across various canonical classification problems. During the terminal phase of training a deep neural network, the feature embedding of all examples of the same class tend to collapse to a single representation, and the features of different classes tend to separate as much as possible. Neural collapse is often studied through a simplified model, called the unconstrained feature representation, in which the model is assumed to have "infinite expressivity" and can map each data point to any arbitrary representation. In this work, we propose a more realistic variant of the unconstrained feature representation that takes the limited expressivity of the network into account. Empirical evidence suggests that the memorization of noisy data points leads to a degradation (dilation) of the neural collapse. Using a model of the memorization-dilation (M-D) phenomenon, we show one mechanism by which different losses lead to different performances of the trained network on noisy data. Our proofs reveal why label smoothing, a modification of cross-entropy empirically observed to produce a regularization effect, leads to improved generalization in classification tasks.}}, author = {{Nguyen, Duc Anh and Levie, Ron and Lienen, Julian and Kutyniok, Gitta and Hüllermeier, Eyke}}, booktitle = {{International Conference on Learning Representations, ICLR}}, location = {{Kigali, Ruanda}}, title = {{{Memorization-Dilation: Modeling Neural Collapse Under Noise}}}, year = {{2023}}, } @unpublished{45814, abstract = {{Label noise poses an important challenge in machine learning, especially in deep learning, in which large models with high expressive power dominate the field. Models of that kind are prone to memorizing incorrect labels, thereby harming generalization performance. Many methods have been proposed to address this problem, including robust loss functions and more complex label correction approaches. Robust loss functions are appealing due to their simplicity, but typically lack flexibility, while label correction usually adds substantial complexity to the training setup. In this paper, we suggest to address the shortcomings of both methodologies by "ambiguating" the target information, adding additional, complementary candidate labels in case the learner is not sufficiently convinced of the observed training label. More precisely, we leverage the framework of so-called superset learning to construct set-valued targets based on a confidence threshold, which deliver imprecise yet more reliable beliefs about the ground-truth, effectively helping the learner to suppress the memorization effect. In an extensive empirical evaluation, our method demonstrates favorable learning behavior on synthetic and real-world noise, confirming the effectiveness in detecting and correcting erroneous training labels.}}, author = {{Lienen, Julian and Hüllermeier, Eyke}}, booktitle = {{arXiv:2305.13764}}, title = {{{Mitigating Label Noise through Data Ambiguation}}}, year = {{2023}}, } @inproceedings{33734, abstract = {{Many applications require explainable node classification in knowledge graphs. Towards this end, a popular ``white-box'' approach is class expression learning: Given sets of positive and negative nodes, class expressions in description logics are learned that separate positive from negative nodes. Most existing approaches are search-based approaches generating many candidate class expressions and selecting the best one. However, they often take a long time to find suitable class expressions. In this paper, we cast class expression learning as a translation problem and propose a new family of class expression learning approaches which we dub neural class expression synthesizers. Training examples are ``translated'' into class expressions in a fashion akin to machine translation. Consequently, our synthesizers are not subject to the runtime limitations of search-based approaches. We study three instances of this novel family of approaches based on LSTMs, GRUs, and set transformers, respectively. An evaluation of our approach on four benchmark datasets suggests that it can effectively synthesize high-quality class expressions with respect to the input examples in approximately one second on average. Moreover, a comparison to state-of-the-art approaches suggests that we achieve better F-measures on large datasets. For reproducibility purposes, we provide our implementation as well as pretrained models in our public GitHub repository at https://github.com/dice-group/NeuralClassExpressionSynthesis}}, author = {{KOUAGOU, N'Dah Jean and Heindorf, Stefan and Demir, Caglar and Ngonga Ngomo, Axel-Cyrille}}, booktitle = {{The Semantic Web - 20th Extended Semantic Web Conference (ESWC 2023)}}, editor = {{Pesquita, Catia and Jimenez-Ruiz, Ernesto and McCusker, Jamie and Faria, Daniel and Dragoni, Mauro and Dimou, Anastasia and Troncy, Raphael and Hertling, Sven}}, keywords = {{Neural network, Concept learning, Description logics}}, location = {{Hersonissos, Crete, Greece}}, pages = {{209 -- 226}}, publisher = {{Springer International Publishing}}, title = {{{Neural Class Expression Synthesis}}}, doi = {{https://doi.org/10.1007/978-3-031-33455-9_13}}, volume = {{13870}}, year = {{2023}}, } @unpublished{45244, abstract = {{Label noise poses an important challenge in machine learning, especially in deep learning, in which large models with high expressive power dominate the field. Models of that kind are prone to memorizing incorrect labels, thereby harming generalization performance. Many methods have been proposed to address this problem, including robust loss functions and more complex label correction approaches. Robust loss functions are appealing due to their simplicity, but typically lack flexibility, while label correction usually adds substantial complexity to the training setup. In this paper, we suggest to address the shortcomings of both methodologies by "ambiguating" the target information, adding additional, complementary candidate labels in case the learner is not sufficiently convinced of the observed training label. More precisely, we leverage the framework of so-called superset learning to construct set-valued targets based on a confidence threshold, which deliver imprecise yet more reliable beliefs about the ground-truth, effectively helping the learner to suppress the memorization effect. In an extensive empirical evaluation, our method demonstrates favorable learning behavior on synthetic and real-world noise, confirming the effectiveness in detecting and correcting erroneous training labels.}}, author = {{Lienen, Julian and Hüllermeier, Eyke}}, booktitle = {{arXiv:2305.13764}}, title = {{{Mitigating Label Noise through Data Ambiguation}}}, year = {{2023}}, } @article{45868, abstract = {{Perfect vector vortex beams (PVVBs) have attracted considerable interest due to their peculiar optical features. PVVBs are typically generated through the superposition of perfect vortex beams, which suffer from the limited number of topological charges (TCs). Furthermore, dynamic control of PVVBs is desirable and has not been reported. We propose and experimentally demonstrate hybrid grafted perfect vector vortex beams (GPVVBs) and their dynamic control. Hybrid GPVVBs are generated through the superposition of grafted perfect vortex beams with a multifunctional metasurface. The generated hybrid GPVVBs possess spatially variant rates of polarization change due to the involvement of more TCs. Each hybrid GPVVB includes different GPVVBs in the same beam, adding more design flexibility. Moreover, these beams are dynamically controlled with a rotating half waveplate. The generated dynamic GPVVBs may find applications in the fields where dynamic control is in high demand, including optical encryption, dense data communication, and multiple particle manipulation.}}, author = {{Ahmed, Hammad and Ansari, Muhammad Afnan and Li, Yan and Zentgraf, Thomas and Mehmood, Muhammad Qasim and Chen, Xianzhong}}, issn = {{2041-1723}}, journal = {{Nature Communications}}, keywords = {{General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}}, number = {{1}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Dynamic control of hybrid grafted perfect vector vortex beams}}}, doi = {{10.1038/s41467-023-39599-8}}, volume = {{14}}, year = {{2023}}, }