@article{ZellerVirchow2024, author = {Zeller, Michael C. and Virchow, Fabian}, title = {Far-right leadership in comparison: shifts and continuities in German-speaking movements}, series = {Social Movement Studies}, journal = {Social Movement Studies}, publisher = {Informa}, issn = {1474-2837}, doi = {10.1080/14742837.2024.2430974}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50521}, pages = {1 -- 23}, year = {2024}, abstract = {Leadership has long been acknowledged as a crucial feature of social movement activity. Theorisation has delved into the types of leadership and, more recently, the activities performed by leaders. However, comparative research on leadership and detection of any changes over time is scant. Our paper attends to these tasks by looking at the activities of two German-speaking far-right leaders. For many years, Christian Worch was one of the most active and influential neo-Nazi leaders in Germany, communicating much of his activity and strategy in the mid-2000s through a regular circular (Rundbriefe). Similarly, Martin Sellner, both as leader of the Identitarian movement and independent activist, today exercises an outsized role in the German-speaking far-right scene, including through his regular publications in the magazines Compact and Sezession. Our paper uses data of Worch's and Sellner's writings, scraped from webpages and gathered from archives, in a mixed-methods comparative design to identify the tasks performed by these leaders, and how frequently. Quantitative text analysis techniques guide the qualitative evaluation of leaders' activities and reveal shifts - and continuities - in far-right movement leadership. The paper thereby contributes to scholarship on an important aspect of contemporary far-right movements as well as broader social movement literature on the topic of leadership.}, subject = {Rechtsradikalismus}, language = {en} } @article{YuwonoSchwungSchwung2025, author = {Yuwono, Steve and Schwung, Dorothea and Schwung, Andreas}, title = {Automated leaders and followers selection in Stackelberg games for modular manufacturing systems}, series = {Journal of Intelligent Manufacturing}, journal = {Journal of Intelligent Manufacturing}, publisher = {Springer Nature}, issn = {0956-5515}, doi = {10.1007/s10845-025-02650-0}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-57990}, year = {2025}, abstract = {We propose an automated data-driven mechanism to evaluate each actuator's influence on modular manufacturing system objectives. This mechanism enables automated leader and follower selection in Stackelberg games, which have gained traction in engineering. While leaders typically hold greater priority or influence, systematic methods for assigning leaders and followers remain limited, especially in large-scale applications. As a result, many rely on empirical analysis to assign leaders and followers, without confirming if the selected setup is optimal. Therefore, in this paper, we develop an automated mechanism to evaluate the influence of each player on the global objectives of modular manufacturing systems, applicable to both single- and multi-objective scenarios. We validate the proposed approach within an industrial control scenario, using a modular Bulk Good System and its larger-scale arrangement with sequential and serial-parallel processes. We focus on three objectives, including production flow disruption prevention, power consumption reduction, and production demand fulfilment. Finally, we implement a self-learning algorithm utilizing Modular State-based Stackelberg Games, where leaders and followers are selected using our approach, which leads to encouraging results.}, subject = {Industrie 4.0}, language = {en} } @article{YuwonoHussainSchwungetal.2025, author = {Yuwono, Steve and Hussain, Ahmar Kamal and Schwung, Dorothea and Schwung, Andreas}, title = {Self-optimization in distributed manufacturing systems using Modular State-based Stackelberg games}, series = {Journal of Manufacturing Systems}, volume = {80}, journal = {Journal of Manufacturing Systems}, publisher = {Elsevier}, issn = {0278-6125}, doi = {10.1016/j.jmsy.2025.03.025}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-55471}, pages = {578 -- 594}, year = {2025}, abstract = {In this study, we introduce Modular State-based Stackelberg Games (Mod-SbSG), a novel game structure developed for distributed self-learning in modular manufacturing systems. Mod-SbSG enhances cooperative decision-making among self-learning agents within production systems by integrating State-based Potential Games (SbPG) with Stackelberg games. This hierarchical structure assigns more important modules of the manufacturing system a first-mover advantage, while less important modules respond optimally to the leaders' decisions. This decision-making process differs from typical multi-agent learning algorithms in manufacturing systems, where decisions are made simultaneously. We provide convergence guarantees for the novel game structure and design learning algorithms to account for the hierarchical game structure. We further analyse the effects of single-leader/multiple-follower and multiple-leader/multiple-follower scenarios within a Mod-SbSG. To assess its effectiveness, we implement and test Mod-SbSG in an industrial control setting using two laboratory-scale testbeds featuring sequential and serial parallel processes. The proposed approach delivers promising results compared to the vanilla SbPG, which reduces overflow by 97.1\%, and in some cases, prevents overflow entirely. Additionally, it decreases power consumption by 5\%-13\% while satisfying the production demand, which significantly improves potential (global objective) values.}, subject = {Intelligente Fertigung}, language = {en} } @article{YalcınkayaDurmazTepeetal.2024, author = {Yal{\c{c}}{\i}nkaya, Orhan and Durmaz, Ufuk and Tepe, Ahmet {\"U}mit and Benim, Ali Cemal and Uysal, {\"U}nal}, title = {Heat and Flow Characteristics of Aerofoil-Shaped Fins on a Curved Target Surface in a Confined Channel for an Impinging Jet Array}, series = {Energies}, volume = {17}, journal = {Energies}, number = {5}, publisher = {MDPI}, issn = {1996-1073}, doi = {10.3390/en17051238}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-46387}, pages = {21}, year = {2024}, abstract = {The main purpose of this investigation was to explore the heat transfer and flow characteristics of aero-foil-shaped fins combined with extended jet holes, specifically focusing on their feasibility in cooling turbine blades. In this study, a comprehensive investigation was carried out by applying impinging jet array cooling (IJAC) on a semi-circular curved surface, which was roughened using aerofoil-shaped fins. Numerical computations were conducted under three different Reynolds numbers (Re) ranging from 5000 to 25,000, while nozzle-to-target surface spacings (S/d) ranged from 0.5 to 8.0. Furthermore, an assessment was made of the impact of different fin arrangements, single-row (L1), double-row (L2), and triple-row (L3), on convective heat transfer. Detailed examinations were performed on area-averaged and local Nusselt (Nu) numbers, flow properties, and the thermal performance criterion (TPC) on finned and smooth target surfaces. The study's results revealed that the use of aerofoil-shaped fins and the reduction in S/d, along with surface roughening, led to significant increases in the local and area-averaged Nu numbers compared to the conventional IJAC scheme. The most notable heat transfer enhancement was observed at S/d = 0.5 utilizing extended jets and the surface design incorporating aerofoil-shaped fins. Under these specific conditions, the maximum heat transfer enhancement reached 52.81\%. Moreover, the investigation also demonstrated that the highest TPC on the finned surface was achieved when S/d = 2.0 for L2 at Re = 25,000, resulting in a TPC value of 1.12. Furthermore, reducing S/d and mounting aerofoil-shaped fins on the surface yielded a more uniform heat transfer distribution on the relevant surface than IJAC with a smooth surface, ensuring a relatively more uniform heat transfer distribution to minimize the risk of localized overheating.}, subject = {Beschaufelung}, language = {en} } @article{WolfUlrichBraun2023, author = {Wolf, Dominik Werner and Ulrich, Markus and Braun, Alexander}, title = {Novel developments of refractive power measurement techniques in the automotive world}, series = {Metrologia}, volume = {60}, journal = {Metrologia}, number = {064001}, publisher = {IOP Publishing}, issn = {1681-7575}, doi = {10.1088/1681-7575/acf1a4}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-41484}, year = {2023}, abstract = {Refractive power measurements serve as the primary quality standard in the automotive glazing industry. In the light of autonomous driving new optical metrics are becoming more and more popular for specifying optical quality requirements for the windshield. Nevertheless, the link between those quantities and the refractive power needs to be established in order to ensure a holistic requirement profile for the windshield. As a consequence, traceable high-resolution refractive power measurements are still required for the glass quality assessment. Standard measurement systems using Moir{\´e} patterns for refractive power monitoring in the automotive industry are highly resolution limited, wherefore they are insufficient for evaluating the camera window area. Consequently, there is a need for more sophisticated refractive power measurement systems that provide a higher spatial resolution. In addition, a calibration procedure has to be developed in order to guarantee for comparability of the measurement results. For increasing the resolution, a measurement setup based on an auto-correlation algorithm is tested in this paper. Furthermore, a calibration procedure is established by using a single reference lens with a nominal refractive power of 100 km-1. For the calibration of the entire measurement range of the system, the lens is tilted by an inclination angle orthogonal to the optical axis. The effective refractive power is then given by the Kerkhof model. By adopting the measurement and calibration procedure presented in this paper, glass suppliers in the automotive industry will be able to detect relevant manufacturing defects within the camera window area more accurately paving the way for a holistic quality assurance of the windshield for future advanced driver-assistance system (ADAS) functionalities. Concurrently, the traceability of the measurement results is ensured by establishing a calibration chain based on a single reference lens, which is traced back to international standards.}, language = {en} } @article{WojciechowskiPogscheba2022, author = {Wojciechowski, Manfred and Pogscheba, Patrick}, title = {Building a COVID-Safe Navigation App Using a Meta-Model Based Context Server}, series = {sensors}, volume = {22}, journal = {sensors}, number = {24}, publisher = {MDPI}, issn = {1424-8220}, doi = {10.3390/s22249890}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-39570}, pages = {1 -- 14}, year = {2022}, abstract = {Building context-aware applications is an already widely researched topic. It is our belief that context awareness has the potential to supplement the Internet of Things, when a suitable methodology including supporting tools will ease the development of context-aware applications. We believe that a meta-model based approach can be key to achieving this goal. In this paper, we present our meta-model based methodology, which allows us to define and build application-specific context models and the integration of sensor data without any programming. We describe how that methodology is applied with the implementation of a relatively simple context-aware COVID-safe navigation app. The outcome showed that programmers with no experience in context-awareness were able to understand the concepts easily and were able to effectively use it after receiving a short training. Therefore, context-awareness is able to be implemented within a short amount of time. We conclude that this can also be the case for the development of other context-aware applications, which have the same context-awareness characteristics. We have also identified further optimization potential, which we will discuss at the conclusion of this article.}, language = {en} } @article{WohlersMuellerBraun2022, author = {Wohlers, Luis Constantin and M{\"u}ller, Patrick and Braun, Alexander}, title = {Original image noise reconstruction for spatially-varying filtered driving scenes}, series = {Electronic Imaging: Society for Imaging Science and Technology}, volume = {34}, journal = {Electronic Imaging: Society for Imaging Science and Technology}, number = {16}, publisher = {Society for Imaging Science and Technology}, issn = {2470-1173}, doi = {10.2352/EI.2022.34.16.AVM-214}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-41479}, pages = {1 -- 7}, year = {2022}, language = {en} } @article{WittpahlDeeganBlacketal.2021, author = {Wittpahl, Christian and Deegan, Brian and Black, Bob and Braun, Alexander}, title = {An analytic-numerical image flicker study to test novel flicker metrics}, series = {Electronic Imaging: Society for Imaging Science and Technology}, journal = {Electronic Imaging: Society for Imaging Science and Technology}, number = {17}, publisher = {Society for Imaging Science and Technology}, issn = {2470-1173}, doi = {10.2352/ISSN.2470-1173.2021.17.AVM-183}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-35671}, pages = {1 -- 8}, year = {2021}, language = {en} } @article{WinterDiehlTelaaretal.2024, author = {Winter, Franziska Luise and Diehl, Patrick and Telaar, Pascal and Watermann, Clara Maria and Kaluza, Stefan and Muhler, Martin and Apfel, Ulf-Peter and Zeidler-Fandrich, Barbara}, title = {Influence of the catalyst precursor for cobalt on activated carbon applied in ammonia decomposition}, series = {Catalysis Today}, volume = {429}, journal = {Catalysis Today}, publisher = {Elsevier}, issn = {0920-5861}, doi = {10.1016/j.cattod.2023.114502}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-46600}, pages = {9}, year = {2024}, abstract = {Ammonia is a key compound for storing and transporting green hydrogen. However, the efficient release of stored hydrogen through thermocatalytic ammonia decomposition is achievable only at temperatures around 600 °C, particularly with non-noble metal-based catalysts, which prove to be both ecologically and economically more feasible. In this study, electrically conductive activated carbon was selected as the catalyst support, chosen specifically for its suitability in achieving more energy-efficient direct reactor heating through the ohmic resistance of the catalysts. Cobalt salts were wet impregnated on activated carbon investigating the influence of different precursors (cobalt nitrate and cobalt acetate) and pyrolysis temperatures (400 °C and 600 °C) under N2 flow on the cobalt particle size and the incorporation of cobalt into the carbon matrix. TEM imaging and CO-chemisorption revealed well dispersed cobalt particles with sizes below 10 nm for the catalysts synthesized from the cobalt nitrate precursor. On the other hand, cobalt acetate led to about nine times larger Co agglomerates, which were partially detached from the carbon matrix. Moreover, this substantial difference in the Co particle size results in a significantly higher ammonia conversion for cobalt nitrate-based catalysts, achieving 94 \% of ammonia conversion at 600 °C. Furthermore, the long-term stability test of the cobalt nitrate-based catalyst resulted in a slight deactivation of only 2 \% ammonia conversion at 500 °C.}, subject = {Katalyse}, language = {en} } @article{WeinzierlLepaAckermann2018, author = {Weinzierl, Stefan and Lepa, Steffen and Ackermann, David}, title = {A measuring instrument for the auditory perception of rooms: The Room Acoustical Quality Inventory (RAQI)}, series = {The Journal of the Acoustical Society of America}, volume = {144}, journal = {The Journal of the Acoustical Society of America}, number = {3}, publisher = {Acoustical Society of America}, issn = {0001-4966}, doi = {10.1121/1.5051453}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-58954}, pages = {1245 -- 1257}, year = {2018}, abstract = {With the Room Acoustical Quality Inventory (RAQI), a measuring instrument for the perceptual space of performance venues for music and speech has been developed. First, a focus group with room acoustical experts determined relevant aspects of room acoustical impression in the form of a comprehensive list of 50 uni- and bipolar items in different categories. Then, n = 190 subjects rated their acoustical impression of 35 binaurally simulated rooms from 2 listening positions, with symphonic orchestra, solo trumpet, and dramatic speech as audio content. Subsequent explorative and confirmative factor analyses of the questionnaire data resulted in three possible solutions with four, six, and nine factors of room acoustical impression. The factor solutions, as well as the related RAQI items, were tested in terms of reliability, validity, and several types of measurement invariance, and were cross-validated by a follow-up experiment with a subsample of 46\% of the original participants, which provided re-test reliabilities and stability coefficients for all RAQI constructs. The resulting psychometrically evaluated measurement instrument can be used for room quality assessment, acoustical planning, and the further development of room acoustical parameters in order to predict primary acoustical qualities of venues for music and speech.}, language = {en} }