@article{62000, author = {{Claes, Leander and Koch, Kevin and Friesen, Olga and Meihost, Lars}}, issn = {{2681-4617}}, journal = {{Acta Acustica}}, number = {{65}}, publisher = {{EDP Sciences}}, title = {{{Machine Learning-Supported Inverse Measurement Procedure for Broadband, Temperature Dependent Piezoelectric Material Parameters}}}, doi = {{10.1051/aacus/2025044}}, volume = {{9}}, year = {{2025}}, } @article{54837, author = {{Claes, Leander and Lankeit, Johannes and Winkler, Michael}}, issn = {{1793-6314}}, journal = {{Mathematical Models and Methods in Applied Sciences}}, number = {{11}}, pages = {{2465--2512}}, publisher = {{World Scientific Pub Co Pte Ltd}}, title = {{{A model for heat generation by acoustic waves in piezoelectric materials: Global large-data solutions}}}, doi = {{10.1142/s0218202525500447}}, volume = {{35}}, year = {{2025}}, } @inproceedings{59689, author = {{Friesen, Olga and Meihost, Lars and Koch, Kevin and Claes, Leander and Henning, Bernd}}, location = {{Copenhagen}}, title = {{{Estimation of piezoelectric material parameters under varying electric field conditions}}}, doi = {{10.71568/DASDAGA2025.078}}, year = {{2025}}, } @article{59056, author = {{Seeger, Karl and Genovese, Matteo and Schlüter, Alexander and Kockel, Christina and Corigliano, Orlando and Díaz Canales, Edith Benjamina and Praktiknjo, Aaron and Fragiacomo, Petronilla}}, issn = {{0360-3199}}, journal = {{International Journal of Hydrogen Energy}}, pages = {{558--576}}, publisher = {{Elsevier BV}}, title = {{{Techno-economic analysis of hydrogen and green fuels supply scenarios assessing three import routes: Canada, Chile, and Algeria to Germany}}}, doi = {{10.1016/j.ijhydene.2025.02.379}}, volume = {{116}}, year = {{2025}}, } @article{60837, abstract = {{In light of growing demands for resource efficiency and sustainability in vehicle engineering, the environmentally compatible separation of structural adhesive joints is gaining increasing relevance. This study presents a comparative analysis of two physically based debonding methods: the established hot-air process and a cryogenic cold process based on liquid nitrogen (LN2). The primary objective is to assess the ecological impact and process-related sustainability of both approaches. Experimental investigations were conducted on a component-representative triple-sheet structure that simulates common automotive flange joints. Thermal input was applied either by convective heating using a hot air gun or by direct cooling through a contact-based LN2 tool. The resulting temperature profiles were recorded using spatially distributed thermocouples. Subsequently, the outer panel was selectively debonded to replicate a repair scenario, and the mechanical integrity of the remaining adhesive joint was evaluated through Mode I testing of L-shaped specimens. Process data served as input for an Life Cycle Assessment (LCA) according to DIN EN ISO 14040. The cryogenic method achieved a 40% reduction in carbon footprint compared to the hot-air process (0.337 kg vs. 0.559 kg CO2-equivalents), primarily due to its shorter process time and more efficient heat transfer. While the hot-air method’s impact is mainly driven by electrical energy use, that of the cold method stems from cryogenic media consumption. Notwithstanding certain disadvantages in specific impact categories, the LN2-based process exhibits a superior overall ecological performance and signifies a promising solution for repair- and recycling-oriented adhesive separation in structural vehicle applications.}}, author = {{Jordan, Alex and Hermelingmeier, Lucas and Gilich, Julian and Meschut, Gerson and De Santis, Marco Sebastian and Schlüter, Alexander}}, issn = {{2666-3309}}, journal = {{Journal of Advanced Joining Processes}}, keywords = {{Sustainable debonding, Structural adhesives, Sustainable joining technologies, Life Cycle Assessment (LCA), Automotive repair process, Economically efficient debonding}}, publisher = {{Elsevier}}, title = {{{Comparison of the economic efficiency and sustainability of two debonding processes for structurally bonded sills}}}, doi = {{10.1016/j.jajp.2025.100332}}, volume = {{12}}, year = {{2025}}, } @techreport{63209, abstract = {{Die DFG-Projekte AddFeRo-PM (406108415) und AddFeRo-SR (465089065) untersuchten die Potenziale des LB-PBF/M-Verfahrens zur Herstellung von Rotoren für unterschiedliche elektrische Maschinen. Im interdisziplinären Ansatz wurden Materialentwicklung und mechanische sowie elektromagnetische Optimierung verbunden. Im Projekt „AddFeRo-PM“ wurde der Rotor einer permanentmagneterregten Synchron- maschine (PMSM) untersucht. FeSi erwies sich als geeignete Legierung, konnte aber wegen Spannungsrissen nur bis zu 3 % Siliziumanteil (kurz: FeSi3) verarbeitet werden. Mechanische und elektromagnetische Untersuchungen ermöglichten eine 3D-Optimierung der Rotorgeometrie und -struktur. Der Demonstrator wurde additiv gefertigt und zeigt Leicht-baupotenziale sowie reduzierte Drehmomentwelligkeit. Im Folgeprojekt „AddFeRo-SR“ kam eine Hochtemperatur-Bauraumheizung (HTBH) zum Einsatz, die FeSi mit 6,5 % Siliziumanteil verarbeitbar machte, welches bessere elektro- magnetische Eigenschaften bietet. Sie wurde bei einer Synchron-Reluktanzmaschine (SynRM) getestet. Eine hybride Rotorfertigung erwies sich jedoch aufgrund von HTBH-Einschränkungen als ungeeignet, weshalb eine einteilige Fertigung mit FeSi3 umgesetzt wurde. Experimente bestätigten vergleichbare Betriebsergebnisse zur konventionellen Fertigung bei reduzierter Rotormasse. Zusätzlich wurde eine Methodik entwickelt, um additive Verfahren als Ergänzung zur konventionellen Fertigung zu integrieren. Beide Projekte zeigen das Potenzial additiver Fertigung für Leichtbau und Wirkungsgradsteigerung im Elektromaschinenbau und bieten wertvolle Grundlagen für industrielle Anwendungen.}}, author = {{Haase, Michael and Behrendt, Marius and Hengsbach, Florian and Kunnathully Sathees Kumar, Vinay and Magerkohl, Sebastian and Magyar, Balázs and Ponick, Bernd and Schaper, Mirko and Zimmer, Detmar}}, keywords = {{Additive Fertigung, Elektromotor, Leichtbau, Synchronmotor, DFG}}, publisher = {{Technische Informationsbibliothek}}, title = {{{Additive Fertigung im Elektromaschinenbau: Erforschung von Potentialen der additiven Fertigung in Rotoren permanentmagneterregter Synchronmaschinen}}}, doi = {{10.34657/26753}}, year = {{2025}}, } @inproceedings{61753, abstract = {{This paper presents LOLA, a massively multilingual large language model trained on more than 160 languages using a sparse Mixture-of-Experts Transformer architecture. Our architectural and implementation choices address the challenge of harnessing linguistic diversity while maintaining efficiency and avoiding the common pitfalls of multilinguality. Our analysis of the evaluation results shows competitive performance in natural language generation and understanding tasks. Additionally, we demonstrate how the learned expert-routing mechanism exploits implicit phylogenetic linguistic patterns to potentially alleviate the curse of multilinguality. We provide an in-depth look at the training process, an analysis of the datasets, and a balanced exploration of the model{’}s strengths and limitations. As an open-source model, LOLA promotes reproducibility and serves as a robust foundation for future research. Our findings enable the development of compute-efficient multilingual models with strong, scalable performance across languages.}}, author = {{Srivastava, Nikit and Kuchelev, Denis and Moteu Ngoli, Tatiana and Shetty, Kshitij and Röder, Michael and Zahera, Hamada Mohamed Abdelsamee and Moussallem, Diego and Ngonga Ngomo, Axel-Cyrille}}, booktitle = {{Proceedings of the 31st International Conference on Computational Linguistics}}, editor = {{Rambow, Owen and Wanner, Leo and Apidianaki, Marianna and Al-Khalifa, Hend and Eugenio, Barbara Di and Schockaert, Steven}}, pages = {{6420–6446}}, publisher = {{Association for Computational Linguistics}}, title = {{{LOLA – An Open-Source Massively Multilingual Large Language Model}}}, year = {{2025}}, } @article{63091, abstract = {{We present the design and characterization of a guided-wave, bright, and highly frequency non-degenerate parametric down-conversion (PDC) source in thin-film lithium niobate. The source generates photon pairs with wavelengths of 815 nm and 1550 nm, linking the visible wavelength regime with telecommunication wavelengths. We confirm the high quality of the generated single photons by determining a value for the heralded second-order correlation function as low as g_h^(2)=(6.7+/-1.1)*10^8-3). Furthermore, we achieve a high spectral brightness of 0.44·10pairs/(smWGHz) which is two orders of magnitude higher than sources based on weakly guiding waveguides. The shape of the PDC spectrum and the strong agreement between the effective and nominal bandwidth highlight our high fabrication quality of periodically poled waveguides. The good agreement between the measured and simulated spectral characteristics of our source demonstrates our excellent understanding of the PDC process. Our result is a valuable step towards practical and scalable quantum communication networks as well as photonic quantum computing.}}, author = {{Babel, Silia and Bollmers, Laura and Roeder, Franz and Ridder, Werner and Golla, Christian and Köthemann, Ronja and Reineke, Bernhard and Herrmann, Harald and Brecht, Benjamin and Eigner, Christof and Padberg, Laura and Silberhorn, Christine}}, issn = {{1094-4087}}, journal = {{Optics Express}}, number = {{25}}, publisher = {{Optica Publishing Group}}, title = {{{Ultrabright, two-color photon pair source based on thin-film lithium niobate for bridging visible and telecom wavelengths}}}, doi = {{10.1364/oe.571605}}, volume = {{33}}, year = {{2025}}, } @article{62713, abstract = {{Periodically poled thin-film lithium niobate (TFLN) crystals are the fundamental building block for highly-efficient quantum light sources and frequency converters. The efficiency of these devices is strongly dependent on the interaction length between the light and the nonlinear material, scaling quadratically with this parameter. Nevertheless, the fabrication of long, continuously poled areas in TFLN remains challenging, the length of continuously poled areas rarely exceeds 10 mm. In this work, we demonstrate a significant progress in this field achieving the periodic poling of continuous poled areas of 70 mm length with a 3 μm poling period and a close to 50 % duty cycle. We compare two poling electrode design approaches to fabricate long, continuous poled areas. The first approach involves the poling of a single, continuous 70 mm long electrode. The second utilize a segmented approach including the poling of more than 20 individual sections forming together a 70 mm long poling area with no stitching errors. While the continuous electrode allows for faster fabrication, the segmented approach allows to individually optimize the poling resulting in less duty cycle variation. A detailed analysis of the periodic poling results reveals that the results of both are consistent with previously reported poling outcomes for shorter devices. Thus, we demonstrate wafer-scale periodic poling exceeding chiplet-size without any loss in the periodic poling quality. Our work presents a key step towards highly-efficient, narrow-bandwidth and low-pump power nonlinear optical devices.}}, author = {{Bollmers, Laura and Spiegelberg, Noah and Rüsing, Michael and Eigner, Christof and Padberg, Laura and Silberhorn, Christine}}, issn = {{2192-8606}}, journal = {{Nanophotonics}}, pages = {{4761}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Segmented finger electrodes to optimize ultra-long continuous wafer-scale periodic poling in thin-film lithium niobate}}}, doi = {{10.1515/nanoph-2025-0461}}, volume = {{14}}, year = {{2025}}, } @inproceedings{63524, abstract = {{Recommendation systems are essential for delivering personalized content across e-commerce and streaming services. However, traditional methods often fail in cold-start scenarios where new items lack prior interactions. Recent advances in large language models (LLMs) offer a promising alternative. In this paper, we adopt the retrieve-and-recommend framework and propose to fine-tune the LLM jointly on warm-and cold-start next-item recommendation tasks, thus, mitigating the need for separate models for both item types. We computationally compare zero-shot prompting, in-context learning, and fine-tuning using the same LLM backbone, and benchmark them against strong PLM-based baselines. Our findings provide practical insights into the trade-offs between accuracy and computational cost of these methods for next-item recommendation. To enhance reproducibility, we release the source code under https://github. com/HayaHalimeh/LLMs-For-Next-Item-Recommendation.git.}}, author = {{Halimeh, Haya and Freese, Florian and Müller, Oliver}}, booktitle = {{International Conference on Information Systems Development}}, issn = {{2938-5202}}, publisher = {{University of Gdansk, Department of Business Informatics & University of Belgrade, Faculty of Organizational Sciences}}, title = {{{LLMs For Warm and Cold Next-Item Recommendation: A Comparative Study across Zero-Shot Prompting, In-Context Learning and Fine-Tuning}}}, doi = {{10.62036/isd.2025.68}}, year = {{2025}}, } @inproceedings{63523, abstract = {{Data spaces have become a strategic pillar of Europe's digital agenda, enabling sovereign, legally compliant data sharing within decentralized ecosystems. As data space initiatives evolve, personalized recommendations are increasingly recognized as key use cases. However, traditional recommendation approaches typically rely on centralized aggregation of user behavior data-directly conflicting with the core ethos of data spaces: sovereignty, privacy, and trust. Federated recommendation systems offer a promising alternative by training models locally and exchanging only intermediate parameters to build a global model. Despite this potential, the integration of federated recommendation techniques and data space architectures remains largely underexplored in research and practice. This paper addresses this gap by designing and evaluating a prototype of a federated recommendation system specifically tailored for data spaces and compliant with their underlying infrastructure. Our findings highlight the viability of developing privacy-preserving, collaborative recommendation systems within data spaces, and contribute to the broader adoption of AI across these emerging ecosystems.}}, author = {{Halimeh, Haya and zur Heiden, Philipp}}, booktitle = {{2025 27th International Conference on Business Informatics (CBI)}}, publisher = {{IEEE}}, title = {{{Preserving Sovereignty and Privacy for Personalization: Designing a Federated Recommendation System for Data Spaces}}}, doi = {{10.1109/cbi68102.2025.00019}}, year = {{2025}}, } @inproceedings{63525, abstract = {{Recommender systems (RS) can support sustainable development by steering users toward more sustainable choices. Sustainability-aware explanations represent one avenue for contributing to this goal by foregrounding the environmental and social aspects of the recommended products or services. This paper advances the line of research on sustainability-aware explanations by integrating nudging mechanisms into their design and by evaluating their effectiveness through a randomized between-subjects online vignette experiment across two item domains (). Our findings offer actionable design guidelines for building RS that foster sustainability-aware decision making and enrich the empirical foundation for impact-oriented research on explanation in RS. }}, author = {{Halimeh, Haya and Müller, Oliver}}, location = {{Prague, Czech Republic}}, title = {{{Towards Greener Choices: Decision Information Nudging for Sustainability-Aware Recommender Explanations}}}, doi = {{10.1007/978-3-032-13342-7}}, year = {{2025}}, } @inproceedings{63527, author = {{Henkenjohann, Mark and Nolte, Udo and Jahneke, Julien and Reimer, Oliver and Abrams, Stefan and Sion, Fabian and Henke, Christian and Trächtler, Ansgar and Schubert, Sebastian and Pfifer, Harald}}, booktitle = {{AIAA SCITECH 2025 Forum}}, publisher = {{American Institute of Aeronautics and Astronautics}}, title = {{{Dynamic Wind Tunnel Testing of an INDI-Based Flight Controller for a Tiltrotor-VTOL}}}, doi = {{10.2514/6.2025-2083}}, year = {{2025}}, } @inproceedings{63528, author = {{Reiling, Fabian and Bause, Maximilian and Gröger, Stefan and Henke, Christian and Koppert, Steven and Trächtler, Ansgar}}, booktitle = {{2025 11th International Conference on Automation, Robotics, and Applications (ICARA)}}, publisher = {{IEEE}}, title = {{{Development of a Learning-Based Control System for Robot-Assisted Grinding of Rubber Roller}}}, doi = {{10.1109/icara64554.2025.10977606}}, year = {{2025}}, } @techreport{46047, abstract = {{This study examines the impact of tax certainty through advance tax rulings (ATRs) on firms' risky investments under cash flow and tax uncertainty. Both firms and governments have expressed growing concern about increasing tax uncertainty, due to frequent tax reforms and the difficulty in applying ambiguous tax laws and anticipating audit outcomes. One remedy is the provision of ATRs, which offer upfront clarification of tax issues to reduce tax uncertainty and increase risk-taking. We analyze how these uncertainties, along with different tax rates, loss offset provisions, and ATR fees affect investment strategies. Our results suggest, first, that ATRs encourage riskier investments, particularly in tax regimes with generous loss offsets. We identify optimal ranges of ATR fees that benefit firms and tax authorities. Second, we show that it may be beneficial to design ATRs with a low or negative fee. Third, our study reveals a U-shaped relationship between firms' risk aversion and their willingness to pay for tax certainty, with willingness being higher for firms at low or high levels of risk aversion. In contrast, moderately risk-averse firms are only willing to accept low fees. Overall, our results highlight the importance of low-cost tax certainty combined with generous loss offset provisions to encourage risky investments.}}, author = {{Chen, An and Hieber, Peter and Sureth-Sloane, Caren}}, title = {{{How Much to Pay for Tax Certainty? The Role of Advance Tax Rulings for Risky Investment under Loss Offset and Tax Uncertainty}}}, doi = {{10.1007/s10797-025-09930-8}}, year = {{2025}}, } @article{63556, author = {{Biehler, Rolf and Engel, Joachim and Frischemeier, Daniel and Podworny, Susanne}}, journal = {{mathematica didactica}}, number = {{2}}, title = {{{Civic Statistical Literacy: Konzept und praxisnahe Umsetzung am Beispiel des Klimawandels}}}, doi = {{10.18716/ojs/md/2025.2297}}, volume = {{48}}, year = {{2025}}, } @inproceedings{63565, author = {{Piskin, Daghan Yüksel and Müller, Helen Martha and Nina Skjæret-Maroni, Nina and Vereijken, Beatrix and Baumeister, Jochen}}, location = {{Piran, Slowenien}}, title = {{{Exergaming Rejuvenates Resting-State Brain Complexity and Modulates Adaptability During Gameplay in Older Adults: An EEG Multiscale Entropy Study}}}, year = {{2025}}, } @inproceedings{63564, author = {{Piskin, Daghan Yüksel and Cobani, Gjergji and Lehmann, Tim and Büchel, Daniel and Baumeister, Jochen}}, location = {{Rimini}}, title = {{{Skilled passing in football may regress following an anterior cruciate ligament injury as a result of cortical changes: preliminary EEG evidence}}}, year = {{2025}}, } @inproceedings{56298, abstract = {{In the general pattern formation (GPF) problem, a swarm of simple autonomous, disoriented robots must form a given pattern. The robots' simplicity imply a strong limitation: When the initial configuration is rotationally symmetric, only patterns with a similar symmetry can be formed [Yamashita, Suzyuki; TCS 2010]. The only known algorithm to form large patterns with limited visibility and without memory requires the robots to start in a near-gathering (a swarm of constant diameter) [Hahn et al.; SAND 2024]. However, not only do we not know any near-gathering algorithm guaranteed to preserve symmetry but most natural gathering strategies trivially increase symmetries [Castenow et al.; OPODIS 2022]. Thus, we study near-gathering without changing the swarm's rotational symmetry for disoriented, oblivious robots with limited visibility (the OBLOT-model, see [Flocchini et al.; 2019]). We introduce a technique based on the theory of dynamical systems to analyze how a given algorithm affects symmetry and provide sufficient conditions for symmetry preservation. Until now, it was unknown whether the considered OBLOT-model allows for any non-trivial algorithm that always preserves symmetry. Our first result shows that a variant of Go-to-the-Average always preserves symmetry but may sometimes lead to multiple, unconnected near-gathering clusters. Our second result is a symmetry-preserving near-gathering algorithm that works on swarms with a convex boundary (the outer boundary of the unit disc graph) and without holes (circles of diameter 1 inside the boundary without any robots).}}, author = {{Gerlach, Raphael and von der Gracht, Sören and Hahn, Christopher and Harbig, Jonas and Kling, Peter}}, booktitle = {{28th International Conference on Principles of Distributed Systems (OPODIS 2024)}}, editor = {{Bonomi, Silvia and Galletta, Letterio and Rivière, Etienne and Schiavoni, Valerio}}, isbn = {{978-3-95977-360-7}}, issn = {{1868-8969}}, keywords = {{Swarm Algorithm, Swarm Robots, Distributed Algorithm, Pattern Formation, Limited Visibility, Oblivious}}, location = {{Lucca, Italy}}, publisher = {{Schloss Dagstuhl -- Leibniz-Zentrum für Informatik}}, title = {{{Symmetry Preservation in Swarms of Oblivious Robots with Limited Visibility}}}, doi = {{10.4230/LIPIcs.OPODIS.2024.13}}, volume = {{324}}, year = {{2025}}, } @unpublished{58544, abstract = {{We introduce a new classification of multimode states with a fixed number of photons. This classification is based on the factorizability of homogeneous multivariate polynomials and is invariant under unitary transformations. The classes physically correspond to field excitations in terms of single and multiple photons, each of which being in an arbitrary irreducible superposition of quantized modes. We further show how the transitions between classes are rendered possible by photon addition, photon subtraction, and photon-projection nonlinearities. We explicitly put forward a design for a multilayer interferometer in which the states for different classes can be generated with state-of-the-art experimental techniques. Limitations of the proposed designs are analyzed using the introduced classification, providing a benchmark for the robustness of certain states and classes. }}, author = {{Kopylov, Denis and Offen, Christian and Ares, Laura and Wembe Moafo, Boris Edgar and Ober-Blöbaum, Sina and Meier, Torsten and Sharapova, Polina and Sperling, Jan}}, title = {{{Multiphoton, multimode state classification for nonlinear optical circuits }}}, year = {{2025}}, }