TY - JOUR A1 - Gärtner, Sebastian A1 - Rank, Daniel A1 - Heberl, Michael A1 - Gaderer, Matthias A1 - Dawoud, Belal A1 - Haumer, Anton A1 - Sterner, Michael T1 - Simulation and Techno-Economic Analysis of a Power-to-Hydrogen Process for Oxyfuel Glass Melting JF - Energies N2 - As an energy-intensive industry sector, the glass industry is strongly affected by the increasingly stringent climate protection targets. As established combustion-based production systems ensure high process stability and glass quality, an immediate switch to low greenhouse gas emission processes is difficult. To approach these challenges, this work investigates a step-by-step integration of a Power-to-Hydrogen concept into established oxyfuel glass melting processes using a simulation approach. This is complemented by a case study for economic analysis on a selected German glass industry site by simulating the power production of a nearby renewable energy park and subsequent optimization of the power-to-hydrogen plant performance and capacities. The results of this study indicate, that the proposed system can reduce specific carbon dioxide emissions by up to 60%, while increasing specific energy demand by a maximum of 25%. Investigations of the impact of altered combustion and furnace properties like adiabatic flame temperature (+25 °C), temperature efficiency (∆ξ = −0.003) and heat capacity flow ratio (∆zHL = −0.009) indicate that pure hydrogen-oxygen combustion has less impact on melting properties than assumed so far. Within the case study, high CO2 abatement costs of 295 €/t CO2-eq. were determined. This is mainly due to the insufficient performance of renewable energy sources. The correlations between process scaling and economic parameters presented in this study show promising potential for further economic optimization of the proposed energy system in the future. KW - Power-to-Gas KW - Hydrogen KW - Electrolysis KW - Oxyfuel KW - Glass Industry Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-22713 N1 - Corresponding author: Sebastian Gärtner VL - 14 IS - 24 PB - MDPI ER - TY - JOUR A1 - Reicheneder, Matthias A1 - Westner, Markus A1 - Matschi, Markus T1 - IT-Near- und Offshoring in deutschen Großunternehmen: Aktueller Stand, Motive und Auswahlkriterien JF - HMD Praxis der Wirtschaftsinformatik N2 - Die vorliegende Studie untersucht die aktuelle IT-Near- und Offshoring-Praxis in deutschen Großunternehmen. Dafür wurden 33 CIOs und IT-Führungskräfte mittels Interviews befragt. Haupttreiber der geografischen Verlagerung von IT-Services ins Ausland ist die Ressourcenverfügbarkeit in anderen Ländern, bedingt durch den Fachkräftemangel in Deutschland. Dies trifft auch auf die Auswahl geeigneter IT-Services für das Near- und Offshoring zu. Während IT-Near- und Offshoring historisch primär aufgrund von Kosteneinsparungen initiiert wurde, spielt dieser Aspekt heute eine untergeordnete Rolle. Die Interviewteilnehmer und -teilnehmerinnen sehen in Kosteneinsparungen zwar immer noch einen positiven Effekt, erwarten aber, dass dieser in Zukunft aufgrund der Angleichung des Kostenniveaus schwinden wird. Die Unternehmen verlagern hauptsächlich Applikationsbetrieb und -entwicklung, erkennen jedoch zunehmend das Potenzial, auch höherwertige Aufgaben, z. B. Projektmanagement und Unternehmensarchitekturmanagement, aus geografisch entfernteren Ländern erbringen zu lassen. Unternehmen, die ausschließlich IT-Nearshoring betreiben, erbringen weniger als ein Drittel ihrer IT-Services aus nahegelegenen Ländern. Firmen mit IT-Offshoring-Präsenzen weisen einen höheren IT-Near‑/Offshoringgrad auf und verlagern knapp die Hälfte der eigenen IT-Serviceerbringung ins Ausland. Die beliebtesten Länder sind Portugal für das Nearshoring und Indien für das Offshoring. KW - Nearshoring KW - Offshoring KW - IT Services KW - Drivers KW - Selection Criteria KW - Large Companies KW - Study KW - Motive KW - Auswahlkriterien KW - Großunternehmen KW - Studie Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-79582 SN - 1436-3011 N1 - Corresponding author der OTH Regensbrg: Markus Westner PB - Springer Nature CY - Wiesbaden ER - TY - JOUR A1 - Mauerer, Wolfgang A1 - Joblin, Mitchell A1 - Tamburri, Damian A1 - Paradis, Carlos A1 - Kazman, Rick A1 - Apel, Sven T1 - In Search of Socio-Technical Congruence: A Large-Scale Longitudinal Study JF - IEEE Transactions on Software Engineering (TSE) N2 - This paper describes a large-scale empirical study investigating the relevance of socio-technical congruence over key basic software quality metrics, namely, bugs and churn. That is, we explore whether alignment or misalignment of social communication structures and technical dependencies in large software projects influences software quality. To this end, we have defined a quantitative and operational notion of socio-technical congruence, which we call /socio-technical motif congruence/ (STMC). STMC is a measure of the degree to which developers working on the same file or on two related files, need to communicate. As socio-technical congruence is a complex and multi-faceted phenomenon, the interpretability of the results is one of our main concerns, so we have employed a careful mixed-methods statistical analysis. In particular, we provide analyses with similar techniques as employed by seminal work in the field to ensure comparability of our results with the existing body of work. The major result of our study, based on an analysis of 25 large open-source projects, is that STMC is /not/ related to project quality measures---software bugs and churn---in any temporal scenario. That is, we find no statistical relationship between the alignment of developer tasks and developer communications on one hand, and project outcomes on the other hand. We conclude that, wherefore congruence does matter as literature shows, then its measurable effect lies elsewhere. KW - Socio-Technical Congruence KW - Human Factors in Software Engineering; KW - Graph Analysis KW - Empirical Software Engineering KW - Quantitative Software Engineering KW - Mixed-Methods Research KW - Socio-Technical Analysis Y1 - 2022 U6 - https://doi.org/10.1109/TSE.2021.3082074 N1 - Corresponding author: Wolfgang Mauerer VL - 48 IS - 8 SP - 3159 EP - 3184 PB - IEEE ER - TY - JOUR A1 - Hofrichter, Andreas A1 - Rank, Daniel A1 - Heberl, Michael A1 - Sterner, Michael T1 - Determination of the optimal power ratio between electrolysis and renewable energy to investigate the effects on the hydrogen production costs JF - International Journal of Hydrogen Energy N2 - Green hydrogen via renewable powered electrolysis has a high relevance in decarbonization and supply security. Achieving economically competitive hydrogen production costs is a major challenge in times of an energy price crisis. Our objective is to show the economically optimal installed capacity of electrolysers in relation to wind and solar power so swift and credible statements can be made regarding the system design. The ratio between renewable generation and electrolysis power as well as scaling effects, operating behaviour and development of costs are considered. Hydrogen production costs are calculated for four exemplary real PV and wind sites and different ratios of electrolysis to renewable power for the year 2020. The ideal ratio for PV systems is between 14% and 73% and for wind between 3.3% and 143% for low and high full load hours. The lowest hydrogen production costs are identified at 2.53 €/kg for 50 MW wind power and 72 MW electrolysis power. The results provide plant constructors the possibility to create a cost-optimized design via an optimum ratio of electrolysis to renewable capacity. Therefore, the procedures for planning and dimensioning of selected systems can be drastically simplified. Y1 - 2023 U6 - https://doi.org/10.1016/j.ijhydene.2022.09.263 SN - 0360-3199 N1 - Corresponding author: Michael Heberl N1 - Corrigendum to “Determination of the optimal power ratio between electrolysis and renewable energy to investigate the effects on the hydrogen production costs” [Int J Hydrogen Energy 48 (5) (2023) 1651–1663] - https://doi.org/10.1016/j.ijhydene.2023.03.128 VL - 48 IS - 5 SP - 1651 EP - 1663 PB - Elsevier ER - TY - JOUR A1 - Müller, Max A1 - Weigl, Stefan A1 - Müller-Williams, Jennifer A1 - Lindauer, Matthias A1 - Rück, Thomas A1 - Jobst, Simon A1 - Bierl, Rudolf A1 - Matysik, Frank-Michael T1 - Comparison of photoacoustic spectroscopy and cavity ring-down spectroscopy for ambient methane monitoring at Hohenpeißenberg JF - Atmospheric Measurement Techniques N2 - With an atmospheric concentration of approximately 2000 parts per billion (ppbV, 10−9), methane (CH4) is the second most abundant greenhouse gas (GHG) in the atmosphere after carbon dioxide (CO2). The task of long-term and spatially resolved GHG monitoring to verify whether climate policy actions are effective is becoming more crucial as climate change progresses. In this paper we report the CH4 concentration readings of our photoacoustic (PA) sensor over a 5 d period at Hohenpeißenberg, Germany. As a reference device, a calibrated cavity ring-down spectrometer, Picarro G2301, from the meteorological observatory of the German Weather Service (DWD) was employed. Trace gas measurements with photoacoustic instruments promise to provide low detection limits at comparably low costs. However, PA devices are often susceptible to cross-sensitivities related to fluctuating environmental conditions, e.g. ambient humidity. The obtained results show that for PA sensor systems non-radiative relaxation effects induced by varying humidity are a non-negligible factor. Applying algorithm compensation techniques, which are capable of calculating the influence of non-radiative relaxation effects on the photoacoustic signal, increase the accuracy of the photoacoustic sensor significantly. With an average relative deviation of 1.11 % from the G2301, the photoacoustic sensor shows good agreement with the reference instrument. Y1 - 2023 U6 - https://doi.org/10.5194/amt-16-4263-2023 SN - 1867-8548 VL - 16 IS - 18 SP - 4263 EP - 4270 PB - Copernicus Publications ER - TY - JOUR A1 - Knödler, Leonard A1 - Dean, Jillian A1 - Knoedler, Samuel A1 - Kauke-Navarro, Martin A1 - Hollmann, Katharina A1 - Alfertshofer, Michael A1 - Helm, Sabrina A1 - Prantl, Lukas A1 - Schliermann, Rainer T1 - Hard shell, soft core? Multi-disciplinary and multi-national insights into mental toughness among surgeons JF - Frontiers in Surgery N2 - Background: With the prevalence of burnout among surgeons posing a significant threat to healthcare outcomes, the mental toughness of medical professionals has come to the fore. Mental toughness is pivotal for surgical performance and patient safety, yet research into its dynamics within a global and multi-specialty context remains scarce. This study aims to elucidate the factors contributing to mental toughness among surgeons and to understand how it correlates with surgical outcomes and personal well-being. Methods: Utilizing a cross-sectional design, this study surveyed 104 surgeons from English and German-speaking countries using the Mental Toughness Questionnaire (MTQ-18) along with additional queries about their surgical practice and general life satisfaction. Descriptive and inferential statistical analyses were applied to investigate the variations in mental toughness across different surgical domains and its correlation with professional and personal factors. Results: The study found a statistically significant higher level of mental toughness in micro-surgeons compared to macro-surgeons and a positive correlation between mental toughness and surgeons' intent to continue their careers. A strong association was also observed between general life satisfaction and mental toughness. No significant correlations were found between the application of psychological skills and mental toughness. Conclusion: Mental toughness varies significantly among surgeons from different specialties and is influenced by professional dedication and personal life satisfaction. These findings suggest the need for targeted interventions to foster mental toughness in the surgical community, potentially enhancing surgical performance and reducing burnout. Future research should continue to explore these correlations, with an emphasis on longitudinal data and the development of resilience-building programs. KW - mental toughness KW - mental health KW - resilience KW - robustness KW - psychology KW - surgery Y1 - 2024 U6 - https://doi.org/10.3389/fsurg.2024.1361406 N1 - Correspondign author der OTH Regensburg: Rainer Schliermann (und Leonard Knoedler) VL - 11 PB - Frontiers ER - TY - JOUR A1 - Savelev, Dmitrii V. A1 - Glavan, Gašper A1 - Belan, Viktoria O. A1 - Belyaeva, Inna A. A1 - Fetisov, Leonid Y. A1 - Shamonin (Chamonine), Mikhail T1 - Resonant Magnetoelectric Effect at Low Frequencies in Layered Polymeric Cantilevers Containing a Magnetoactive Elastomer JF - Applied Sciences N2 - In this work, the resonance enhancement of magnetoelectric (ME) coupling at the two lowest bending resonance frequencies was investigated in layered cantilever structures comprising a magnetoactive elastomer (MAE) slab and a commercially available piezoelectric polymer multilayer. A cantilever was fixed at one end in the horizontal plane and the magnetic field was applied horizontally. Five composite structures, each containing an MAE layer of different thicknesses from 0.85 to 4 mm, were fabricated. The fundamental bending resonance frequency in the absence of a magnetic field varied between roughly 23 and 55 Hz. It decreased with the increasing thickness of the MAE layer, which was explained by a simple theory. The largest ME voltage coefficient of about 7.85 V/A was measured in a sample where the thickness of the MAE layer was ≈2 mm. A significant increase in the bending resonance frequencies in the applied DC magnetic field of 240 kA/m up to 200% was observed. The results were compared with alternative designs for layered multiferroic structures. Directions for future research were also discussed. KW - flexible composite KW - low frequency KW - magnetoactive elastomer KW - magnetoelectric effect KW - piezoelectric polymer Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-30637 N1 - corresponding authors: Dmitry V. Saveliev and Mikhail Shamonin VL - 12 IS - 4 SP - 1 EP - 13 PB - MPDI ER - TY - JOUR A1 - Gebhardt, Jakob A1 - Schlamp, Matthias A1 - Ehrlich, Ingo A1 - Hiermaier, Stefan T1 - Low-velocity impact behavior of elliptic curved composite structures JF - International Journal of Impact Engineering N2 - Although many composite structures are inconsistently curved, such as the leading edges of aircraft wings, the variety of research in impact engineering is almost limited to the impact performance of plates or cylindrically curved specimens. It is not known whether the findings obtained from standardized tests can be transferred to curved structures or which adaptions are required. Therefore, a deeper understanding of the deformation and damage behavior of inconsistently curved structures is essential to transfer the observed impact behavior of flat specimens to general curved structures and therefore to utilize the full lightweight potential of a load-specific design. An accurate description of the procedure as well as the results of the experimental and numerical study of the low-velocity impact behavior of differently single-curved elliptic specimens is presented. To close the research gap of the impact behavior of geometries with curvatures between the plates and simplified leading edges, novel specimens geometries have been derived from established impact test standards. Glassfiber-reinforced specimens are subjected to an instrumented impact test at constant impact energy. This is numerically investigated by a stacked-layer model, which used cohesive zone modeling to enable the simulation of matrix cracking, fiber fracture and delamination. The resulting projected damage areas, as well as the force and deflection histories, were evaluated and section cuts were examined to discuss the damage morphology, formation and propagation process. Significant effects on maximum deflection, compliance and dynamic behavior on the size and morphology of damage were found. KW - Impact damage KW - Impact behavior KW - Curved composite KW - Numerical model KW - GFRP Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-59304 N1 - Corrsponding author: Jakob Gebhardt VL - 180 PB - Elsevier ER - TY - JOUR A1 - Markov-Glazer, Alon A1 - Elbe, Anne-Marie A1 - Schliermann, Rainer T1 - From their eyes: Deaflympic athletes' and coaches' perspectives on mental training JF - Frontiers in sports and active living N2 - INTRODUCTION Sport psychology research has largely overlooked athletes with hearing impairments competing in Deaflympic sports, the designated elite sporting movement for this population. This study therefore explored Deaflympic athletes' and coaches' perspectives on mental training in the elite Deaf sports. METHODS A qualitative approach was used, involving six focus group interviews with 23 athletes (Mage = 33.09; 26.1% female) and four coaches from individual and team Deaf sports. Data were analyzed using reflexive thematic analysis. RESULTS Three themes emerged: sport psychology consultation, the influence of visual orientation on psychological skills and demands, and Deaf sport culture and communication. While participants expressed strong interest in sport psychology, engagement with professionals was limited by accessibility issues, lack of sign language-fluent consultants, and structural barriers. Deaf athletes reported adapting some techniques to match their visual-spatial orientation and both advantages and challenges of visual reliance in sports. Distinct communication dynamics between native signers and spoken-language users within Deaf teams were also revealed. DISCUSSION These findings highlight the importance of culturally sensitive sport psychology frameworks that support the needs and preferences of Deaflympic athletes and promote equitable access to effective mental training resources. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-84183 N1 - Corresponding author der OTH Regensburg: Alon Markov-Glazer VL - 7 PB - Frontiers ER - TY - JOUR A1 - Schulz, Carsten A1 - Vogl, Yannick A1 - Geiger, Benjamin A1 - Schaeffer, Thomas T1 - Vor- und Nachteile einer Lumped-Mass-Modellierung von Förderbändern am Beispiel eines Zwei-Walzensystems JF - Forschung im Ingenieurwesen JF - Engineering Research N2 - Im Betrieb von Förderbändern auftretende Phänomene sind das Bandwandern in Achsrichtung der Walzen und die Bandverformung in der Bandebene [1, S. 142]. Das Bandwandern ist bisher detailliert untersucht [2–4], während die Bandverformung Gegenstand weniger Veröffentlichungen ist. Deshalb wird in diesem Artikel eine Methode zur Berechnung der sich im dynamischen Betrieb einstellenden Verformung eines elastischen Förderbandes vorgestellt. Dazu wird ein Mehrkörpersimulations-Modell basierend auf der Lumped-Mass-Modellierung verwendet. Als Untersuchungsbeispiel dient ein Zwei-Walzensystem mit flexiblen und zylindrischen Walzen, sowie ein flexibles Förderband. Es zeigt sich, dass mit der Lumped-Mass-Modellierung eine dynamische Bandverformung, die von der gewählten Diskretisierung abhängt, berechnet werden kann. Aufgrund dieser Abhängigkeit ist es notwendig eine Konvergenzanalyse durchzuführen. Zusätzlich ist darauf zu achten, dass die künstliche Anregung aufgrund der Lumped-Mass-Modellierung nicht mit einer Eigenfrequenz des Modells zusammenfällt. N2 - Phenomena occurring in the operation of conveyor belts are belt walking in the axial direction of the rollers and belt deformation in the belt plane [1, S. 142]. Whereas [2,3,4] investigate the first effect in detail [2,3,4], the latter is mostly neglected. The authors therefore focus on the calculation of the deformation of the elastic conveyor belt during dynamic operation using a flexible multibody approach. To consider the flexibility of the belt in an efficient way, the model uses the well-known Lumped-Mass-Approach. The discretization of the model (number and distance of masses) thereby impacts the shape of the band deformation. The article investigates the minimum required discretization for two dimensions, the effect on the system response and the influence on the computation time. As an example, a two-roller system with flexible, cylindrical rolls and a flexible conveyor belt is used. The results of the model will be compared with theoretical expectations and show very promising results. T2 - Pros and cons of Lumped Mass Modelling of conveyor belts using a two-roller system Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-72891 SN - 0015-7899 N1 - Corresponding author der OTH Regensburg: Carsten Schulz VL - 88 IS - 1 PB - Springer Vieweg CY - Belrin ; Heidelberg ER - TY - JOUR A1 - Fetisov, Yuri K. A1 - Chashin, Dmitri V. A1 - Savelev, Dmitrii V. A1 - Fetisov, Leonid Y. A1 - Shamonin (Chamonine), Mikhail T1 - Anisotropic Magnetoelectric Effect in a Planar Heterostructure Comprising Piezoelectric Ceramics and Magnetostrictive Fibrous Composite JF - Materials N2 - The direct magnetoelectric (ME) effect is investigated in a planar structure comprising mechanically coupled layers of a magnetostrictive fibrous composite (MFC) and a piezoelectric ceramics (lead zirconate titanate, PZT). The MFC is an array of Ni-wires with a diameter of 200 mu m that are aligned parallel to each other in a single layer. The wires are separated by a distance of 250 or 500 mu m and fixed in a polyamide matrix. The structure was placed in a tangential constant field H and was excited by an alternating magnetic field h parallel to H, while the voltage generated by the PZT layer was measured. The resulting field dependences of the magnetization M(H) and the magnetostriction lambda(H) were determined by the orientation of the field H in the plane of the structure and the distance between the Ni-wires. The ME coupling coefficient of the structure decreased from 4.8 to 0.25 V/A when the orientation of H was changed from parallel to perpendicular to Ni-wires. With an increase in the excitation field amplitude h, a nonlinear ME effect in the output voltage, namely frequency doubling, was observed. The frequency and field dependences of the efficiency of the ME transduction in the MFC-piezoelectric heterostructure are well described by the existing theory. KW - composite KW - frequency doubling KW - heterostructure KW - magnetoelectric effect KW - magnetostrictive fiber KW - piezoelectric ceramic material Y1 - 2019 U6 - https://doi.org/10.3390/ma12193228 N1 - Corresponding authors: Yuri Fetisov, Mikhail Shamonin VL - 12 IS - 19 SP - 1 EP - 13 PB - MDPI CY - Basel ER - TY - GEN A1 - Saffert, Anne-Sophie A1 - Melzner, Maximilian A1 - Dendorfer, Sebastian T1 - Biomechanical Analysis of the Right Elevated Glenohumeral Joint in Violinists during Legato-Playing T2 - Biomdlore 2021: 21-23 October 2021 Vilnius/Trakai, Lithuania N2 - BACKGROUND: Many statistics reveal that violin players suffer most often from musculoskeletal disorders compared to musicians of other instrument groups. A common phenomenon, especially observed in violin beginners, is the tendency to elevate the right shoulder during playing the violin. This can probably lead to serious disorders in long-term practice with repetitive movements. OBJECTIVE: For this reason, this study investigated the relationship between the right shoulder elevation and the force in the right glenohumeral joint during violin playing. It was hypothesized that the forces in the right glenohumeral joint are higher during playing with the right shoulder raised compared to playing in normal posture. METHODS: Motion capture data from four experienced violinists was recorded and processed by means of musculoskeletal simulation to get the force and elevation angle while playing with raised shoulder and in normal position. RESULTS: The results indicate that the absolute values of the resulting force, as well as the forces in the mediolateral, inferosuperior, and anteroposterior directions, are higher in playing the violin with the shoulder raised than in a normal posture. CONCLUSIONS: Elevating the right shoulder while playing the violin may pose a potential problem. Y1 - 2021 U6 - https://doi.org/10.3233/THC-219001 N1 - Veröffentlicht in: Technology and Health Care, vol. 30, no. 1 (Selected Papers From the 13th International Conference BIOMDLORE 2021), pp. 177-186, 2022 ER - TY - JOUR A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Ruwisch, Kevin A1 - Wollschlaeger, Joachim A1 - Shamonin (Chamonine), Mikhail T1 - Magnetoelectric Response of Laminated Cantilevers Comprising a Magnetoactive Elastomer and a Piezoelectric Polymer, in Pulsed Uniform Magnetic Fields JF - Sensors N2 - The voltage response to pulsed uniform magnetic fields and the accompanying bending deformations of laminated cantilever structures are investigated experimentally in detail. The structures comprise a magnetoactive elastomer (MAE) slab and a commercially available piezoelectric polymer multilayer. The magnetic field is applied vertically and the laminated structures are customarily fixed in the horizontal plane or, alternatively, slightly tilted upwards or downwards. Six different MAE compositions incorporating three concentrations of carbonyl iron particles (70 wt%, 75 wt% and 80 wt%) and two elastomer matrices of different stiffness are used. The dependences of the generated voltage and the cantilever's deflection on the composition of the MAE layer and its thickness are obtained. The appearance of the voltage between the electrodes of a piezoelectric material upon application of a magnetic field is considered as a manifestation of the direct magnetoelectric (ME) effect in a composite laminated structure. The ME voltage response increases with the increasing total quantity of the soft-magnetic filler in the MAE layer. The relationship between the generated voltage and the cantilever's deflection is established. The highest observed peak voltage around 5.5 V is about 8.5-fold higher than previously reported values. The quasi-static ME voltage coefficient for this type of ME heterostructures is about 50 V/A in the magnetic field of approximate to 100 kA/m, obtained for the first time. The results could be useful for the development of magnetic field sensors and energy harvesting devices relying on these novel polymer composites. KW - cantilever KW - composites KW - DEMAGNETIZING FACTORS KW - direct magnetoelectric effect KW - laminated structure KW - magnetic field sensor KW - magnetoactive elastomer KW - piezoelectric polymer Y1 - 2021 U6 - https://doi.org/10.3390/s21196390 N1 - Corresponding authors: Gašper Glavan, Mikhail Shamonin VL - 21 IS - 19 SP - 1 EP - 19 PB - MDPI CY - Basel ER - TY - JOUR A1 - Savelev, Dmitrii V. A1 - Belyaeva, Inna A. A1 - Chashin, Dmitri V. A1 - Fetisov, Leonid Y. A1 - Romeis, Dirk A1 - Kettl, Wolfgang A1 - Kramarenko, Elena Yu A1 - Saphiannikova, Marina A1 - Stepanov, Gennady V. A1 - Shamonin (Chamonine), Mikhail T1 - Giant extensional strain of magnetoactive elastomeric cylinders in uniform magnetic fields JF - Materials N2 - Elongations of magnetoactive elastomers (MAEs) under ascending–descending uniform magnetic fields were studied experimentally using a laboratory apparatus specifically designed to measure large extensional strains (up to 20%) in compliant MAEs. In the literature, such a phenomenon is usually denoted as giant magnetostriction. The synthesized cylindrical MAE samples were based on polydimethylsiloxane matrices filled with micrometer-sized particles of carbonyl iron. The impact of both the macroscopic shape factor of the samples and their magneto-mechanical characteristics were evaluated. For this purpose, the aspect ratio of the MAE cylindrical samples, the concentration of magnetic particles in MAEs and the effective shear modulus were systematically varied. It was shown that the magnetically induced elongation of MAE cylinders in the maximum magnetic field of about 400 kA/m, applied along the cylinder axis, grew with the increasing aspect ratio. The effect of the sample composition is discussed in terms of magnetic filler rearrangements in magnetic fields and the observed experimental tendencies are rationalized by simple theoretical estimates. The obtained results can be used for the design of new smart materials with magnetic-field-controlled deformation properties, e.g., for soft robotics. KW - magnetostriction KW - magnetoactive elastomer KW - extensional strain KW - hysteresis KW - magnetomechanical effect KW - magnetodeformation Y1 - 2020 U6 - https://doi.org/10.3390/ma13153297 SN - 1996-1944 N1 - Corresponding author: Mikhail Shamonin VL - 13 IS - 15 SP - 1 EP - 17 PB - MDPI CY - Basel ER - TY - JOUR A1 - Schuderer, Matthias A1 - Rill, Georg A1 - Schaeffer, Thomas A1 - Schulz, Carsten T1 - Friction modeling from a practical point of view JF - Multibody System Dynamics N2 - AbstractRegularized static friction models have been used successfully for many years. However, they are unable to maintain static friction in detail. For this reason, dynamic friction models have been developed and published in the literature. However, commercial multibody simulation packages such as Adams, RecurDyn, and Simpack have developed their own specific stick-slip models instead of adopting one of the public domain approaches. This article introduces the fundamentals of these commercial models and their behavior from a practical point of view. The stick-slip models were applied to a simple test model and a more sophisticated model of a festoon cable system using their standard parameters. KW - Multibody dynamics KW - Friction KW - Stick-slip effect KW - Adams KW - RecurDyn KW - Simpack Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-72513 SN - 1384-5640 N1 - Corresponding author: Matthias Schuderer PB - Springernature ER - TY - JOUR A1 - Putz, Christoph A1 - Schirmer, Maximilian A1 - Sattler, Robert A1 - Monkman, Gareth J. T1 - Fabrication of Bisphenol-free Boron-Siloxane Polymers JF - Materials Chemistry and Physics N2 - Interest in the preparation of magnetoactive boron-siloxane polymers (MBP) has been stimulated by recent scientific developments. However, recent regulations have prohibited the inclusion of Bisphenol-A normally employed in the manufacture of commercially available products. In the following publication, two different routes for the preparation of magnetoactive borosiloxane polymers have been taken. First, the possibilities of obtaining homogeneous mixtures of magnetoactive polymers by mixing the magnetic particles with the polymer using solid CO2 (dry ice) and stirring (shearing) are investigated. In the course of the work, an approach for the preparation of reference materials of different viscosities was made to prove the transferability to other elastomers. This is then followed by a brief review of the reaction of the polymer with different solvents in relation to the mixing with particles. In manually kneaded compounds, dispersions ranging from 0.00004 to 0.004 particles per mm3 are common. The process described in this work resulted in agglomerations of no greater than 0.00004 particles per mm3 A possible synthesis route for bisphenol-free boron-siloxanes is then considered, in which for the polymer matrix, polydimethylsilanes (dichloro(methyl)silane), boric acid and iron(III)chloride are used for this purpose by polycondensation. Y1 - 2025 U6 - https://doi.org/10.1016/j.matchemphys.2025.130567 N1 - Corresponding author der OTH Regensburg: Gareth J. Monkman PB - Elsevier ET - Journal Pre-proof ER - TY - JOUR A1 - Rill, Georg A1 - Schaeffer, Thomas A1 - Schuderer, Matthias T1 - LuGre or not LuGre JF - Multibody System Dynamics N2 - The LuGre model is widely used in the analysis and control of systems with friction. Recently, it has even been made available in the commercial multibody dynamics simulation software system Adams. However, the LuGre model exhibits well-known drawbacks like too low and force rate-dependent break-away forces, drift problems during sticking periods, and significant differences in non-stationary situations between the pre-defined friction law and the one produced by the LuGre model. In the present literature, these problems are supposed to come from the model dynamics or its nonlinear nature. However, most of these drawbacks are not simple side effects of a dynamic friction model but are caused in the LuGre approach, as shown here, by a too simple and inconsistent model of the bristle dynamics. Standard examples and a more practical application demonstrate that the LuGre model is not a “what you see is what you get” approach. A dynamic friction model with accurate bristle dynamics and consistent friction force is set up here. It provides insight into the physical basis of the LuGre model dynamics. However, it results in a nonlinear and implicit differential equation, whose solution will not be easy because of the ambiguity of the friction characteristics. The standard workaround, a static model based on simple regularized characteristics, produces reliable and generally satisfactory results but definitely cannot maintain a stick. The paper presents a second-order dynamic friction model, which may serve as an alternative. It can maintain a stick and produces realistic and reliable results. KW - Dynamic friction model KW - LuGre model KW - Asymmetric regularization KW - Break-away force KW - Stick-slip KW - Multibody dynamics Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-65653 N1 - Corresponding author: Georg Rill PB - Springer ER - TY - JOUR A1 - Rill, Georg A1 - Schuderer, Matthias T1 - A Second-Order Dynamic Friction Model Compared to Commercial Stick–Slip Models JF - Modelling N2 - Friction has long been an important issue in multibody dynamics. Static friction models apply appropriate regularization techniques to convert the stick inequality and the non-smooth stick–slip transition of Coulomb’s approach into a continuous and smooth function of the sliding velocity. However, a regularized friction force is not able to maintain long-term stick. That is why dynamic friction models were developed in recent decades. The friction force depends herein not only on the sliding velocity but also on internal states. The probably best-known representative, the LuGre friction model, is based on a fictitious bristle but realizes a too-simple approximation. The recently published second-order dynamic friction model describes the dynamics of a fictitious bristle more accurately. It is based on a regularized friction force characteristic, which is continuous and smooth but can maintain long-term stick due to an appropriate shift in the regularization. Its performance is compared here to stick–slip friction models, developed and launched not long ago by commercial multibody software packages. The results obtained by a virtual friction test-bench and by a more practical festoon cable system are very promising. Thus, the second-order dynamic friction model may serve not only as an alternative to the LuGre model but also to commercial stick–slip models. KW - commercial stick–slip friction models KW - dynamic friction model KW - long-term stick KW - multibody dynamics Y1 - 2023 U6 - https://doi.org/10.3390/modelling4030021 SN - 2673-3951 N1 - Corresponding author: Georg Rill VL - 4 IS - 3 SP - 366 EP - 381 PB - MDPI ER - TY - JOUR A1 - Hausladen, Matthias A1 - Schels, Andreas A1 - Asgharzade, Ali A1 - Buchner, Philipp A1 - Bartl, Mathias A1 - Wohlfartsstätter, Dominik A1 - Edler, Simon A1 - Bachmann, Michael A1 - Schreiner, Rupert T1 - Investigation of Influencing Factors on the Measurement Signal of a CMOS Image Sensor for Measuring Field Emission Currents JF - Sensors Y1 - 2025 U6 - https://doi.org/10.3390/s25051529 N1 - Corresponding author der OTH Regensburg: Matthias Hausladen VL - 25 IS - 5 PB - MDPI ER - TY - JOUR A1 - Markov-Glazer, Alon A1 - Elbe, Anne-Marie A1 - Schliermann, Rainer T1 - The use of psychological skills in deaflympic sport JF - European Journal of Adapted Physical Activity N2 - This study explores the use of psychological skills among Deaflympic athletes and aims to provide initial insights into sport psychology practices in this overlooked population. To this end, the frequency of psychological skills’ usage, usage patterns, and differences between subgroups were examined within this population. The Test of Performance Strategies (TOPS) was administered to 84 German Deaflympic athletes (mean age = 28; 27% female) along with biographical questions (e.g., hearing status). The findings indicate that Deaflympic athletes regularly utilize psychological skills in training and competition, displaying similar usage to that of Olympic athletes. However, only a minority of Deaflympic athletes train their skills with professional consultants. Additionally, relaxation techniques were employed rarely in comparison to the other investigated skills. This study’s findings contribute to the foundation of sport psychology research with Deaflympic athletes and underscore the need for a differentiated approach in tailoring interventions for this population. KW - Deaf culture KW - Deaflympian KW - psychological skills training KW - TOPS Y1 - 2024 U6 - https://doi.org/10.5507/euj.2024.012 VL - 17 IS - 15 PB - European Federation of Adapted Physical Activity CY - Olomouc ER - TY - JOUR A1 - Schwarz, Tobias A1 - Pastötter, Angelina A1 - Tran, T. H. A1 - Schlosser, Marc A1 - Kaulen, Corinna A1 - Lechner, Alfred A1 - Slabon, A. A1 - Kammler, Martin T1 - Effect of temperature on the growth of Cupric and Cuprous Nanoparticles in a wet chemical synthesis JF - Materials Letters N2 - Cuprous oxide (Cu2O) and cupric oxide (CuO) particles were synthesized using a wet chemical surfactant free method at different synthesis temperatures from 25 °C to 60 °C. Morphology, size, and chemical composition of the prepared Cu2O particles were analyzed by FESEM, PXRD, and UV-vis. We discovered that the chemical composition of the Cu2O particles remained unaffected by the synthesis temperature. However, morphology and size of the particles showed a strong temperature dependency. This could be attributed to the temperature induced formation of CuO species from the copper hydroxide (Cu(OH)2) precursor which also functions as copper precursor for the Cu2O particle growth. The cupric oxide species was determined to be the main cause for the formation of micrometer sized particles, whereas with the Cu(OH)2 precursor species for the Cu2O particles nanocubes with smaller edge lengths as well as octahedrons were obtained. KW - Crystal structure KW - Crystal growth KW - Nanoparticle KW - Copper oxide Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-79279 VL - 381 PB - Springer Nature ER - TY - JOUR A1 - Vogl, Yannick A1 - Schulz, Carsten A1 - Schaeffer, Thomas A1 - Geiger, Benjamin T1 - Prediction of the wear behavior of a conveyor belt with flexible rollers JF - Multibody System Dynamics N2 - This paper introduces a method to predict wear behavior in conveyor belt systems using a lumped mass modeling approach. While previous research has focused primarily on lateral belt walking, this study shifts attention to belt deformation and its associated wear. Both significantly affect system efficiency and component lifespan. The authors propose using local frictional power as a wear indicator, leveraging its direct relation to frictional work in established wear models. To solely demonstrate the method, the study simulates a conveyor belt with three flexible rollers and a deformable belt modeled through rigid spheres connected by spring-damper elements. The authors visualize frictional power density across the belt width, distinguishing between running and transverse directions. The results demonstrate that the frictional power distribution depends heavily on discretization quality, particularly due to the polygon effect inherent in the lumped mass approach. A convergence analysis reveals the minimum necessary discretization of the belt, ensuring reliable qualitative results. To support the credibility of the work, this study compares theoretical expectations and initial wear observations from a real belt with the results from the shown approach. The plausibility check already shows promising results. The proposed methodology provides an adaptable framework to evaluate wear in belt-like structures. It can be readily adapted to a variety of multibody dynamics applications and integrated into larger MBS models that include the overall drivetrain and engine control. Future work will focus on refining discretization strategies and contact models, as well as validation of the wear model to enable quantitative predictions. Y1 - 2025 U6 - https://doi.org/10.1007/s11044-025-10097-7 SN - 1384-5640 N1 - Die Preprint-Version ist ebenfalls in diesem Repositorium verzeichnet: https://opus4.kobv.de/opus4-oth-regensburg/8194 PB - Springer CY - Cham ER - TY - JOUR A1 - Mendel, Robert A1 - Rauber, David A1 - Souza Jr., Luis Antonio de A1 - Papa, João Paulo A1 - Palm, Christoph T1 - Error-Correcting Mean-Teacher: Corrections instead of consistency-targets applied to semi-supervised medical image segmentation JF - Computers in Biology and Medicine N2 - Semantic segmentation is an essential task in medical imaging research. Many powerful deep-learning-based approaches can be employed for this problem, but they are dependent on the availability of an expansive labeled dataset. In this work, we augment such supervised segmentation models to be suitable for learning from unlabeled data. Our semi-supervised approach, termed Error-Correcting Mean-Teacher, uses an exponential moving average model like the original Mean Teacher but introduces our new paradigm of error correction. The original segmentation network is augmented to handle this secondary correction task. Both tasks build upon the core feature extraction layers of the model. For the correction task, features detected in the input image are fused with features detected in the predicted segmentation and further processed with task-specific decoder layers. The combination of image and segmentation features allows the model to correct present mistakes in the given input pair. The correction task is trained jointly on the labeled data. On unlabeled data, the exponential moving average of the original network corrects the student’s prediction. The combined outputs of the students’ prediction with the teachers’ correction form the basis for the semi-supervised update. We evaluate our method with the 2017 and 2018 Robotic Scene Segmentation data, the ISIC 2017 and the BraTS 2020 Challenges, a proprietary Endoscopic Submucosal Dissection dataset, Cityscapes, and Pascal VOC 2012. Additionally, we analyze the impact of the individual components and examine the behavior when the amount of labeled data varies, with experiments performed on two distinct segmentation architectures. Our method shows improvements in terms of the mean Intersection over Union over the supervised baseline and competing methods. Code is available at https://github.com/CloneRob/ECMT. KW - Semi-supervised Segmentation KW - Mean-Teacher KW - Pseudo-labels KW - Medical Imaging Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-57790 SN - 0010-4825 N1 - Corresponding author der OTH Regensburg: Robert Mendel VL - 154 IS - March PB - Elsevier ER - TY - JOUR A1 - Graßmann, Felix A1 - Mengelkamp, Judith A1 - Brandl, Caroline A1 - Harsch, Sebastian A1 - Zimmermann, Martina E. A1 - Linkohr, Birgit A1 - Peters, Annette A1 - Heid, Iris M. A1 - Palm, Christoph A1 - Weber, Bernhard H. F. T1 - A Deep Learning Algorithm for Prediction of Age-Related Eye Disease Study Severity Scale for Age-Related Macular Degeneration from Color Fundus Photography JF - Ophtalmology N2 - Purpose Age-related macular degeneration (AMD) is a common threat to vision. While classification of disease stages is critical to understanding disease risk and progression, several systems based on color fundus photographs are known. Most of these require in-depth and time-consuming analysis of fundus images. Herein, we present an automated computer-based classification algorithm. Design Algorithm development for AMD classification based on a large collection of color fundus images. Validation is performed on a cross-sectional, population-based study. Participants. We included 120 656 manually graded color fundus images from 3654 Age-Related Eye Disease Study (AREDS) participants. AREDS participants were >55 years of age, and non-AMD sight-threatening diseases were excluded at recruitment. In addition, performance of our algorithm was evaluated in 5555 fundus images from the population-based Kooperative Gesundheitsforschung in der Region Augsburg (KORA; Cooperative Health Research in the Region of Augsburg) study. Methods. We defined 13 classes (9 AREDS steps, 3 late AMD stages, and 1 for ungradable images) and trained several convolution deep learning architectures. An ensemble of network architectures improved prediction accuracy. An independent dataset was used to evaluate the performance of our algorithm in a population-based study. Main Outcome Measures. κ Statistics and accuracy to evaluate the concordance between predicted and expert human grader classification. Results. A network ensemble of 6 different neural net architectures predicted the 13 classes in the AREDS test set with a quadratic weighted κ of 92% (95% confidence interval, 89%–92%) and an overall accuracy of 63.3%. In the independent KORA dataset, images wrongly classified as AMD were mainly the result of a macular reflex observed in young individuals. By restricting the KORA analysis to individuals >55 years of age and prior exclusion of other retinopathies, the weighted and unweighted κ increased to 50% and 63%, respectively. Importantly, the algorithm detected 84.2% of all fundus images with definite signs of early or late AMD. Overall, 94.3% of healthy fundus images were classified correctly. Conclusions Our deep learning algoritm revealed a weighted κ outperforming human graders in the AREDS study and is suitable to classify AMD fundus images in other datasets using individuals >55 years of age. KW - Senile Makuladegeneration KW - Krankheitsverlauf KW - Mustererkennung KW - Maschinelles Lernen Y1 - 2018 U6 - https://doi.org/10.1016/j.ophtha.2018.02.037 N1 - Corresponding authors: Bernhard H. F. Weber, University of Regensburg, and Christoph Palm VL - 125 IS - 9 SP - 1410 EP - 1420 PB - Elsevier ER - TY - JOUR A1 - Maier, Johannes A1 - Perret, Jerome A1 - Simon, Martina A1 - Schmitt-Rüth, Stephanie A1 - Wittenberg, Thomas A1 - Palm, Christoph T1 - Force-feedback assisted and virtual fixtures based K-wire drilling simulation JF - Computers in Biology and Medicine N2 - One common method to fix fractures of the human hand after an accident is an osteosynthesis with Kirschner wires (K-wires) to stabilize the bone fragments. The insertion of K-wires is a delicate minimally invasive surgery, because surgeons operate almost without a sight. Since realistic training methods are time consuming, costly and insufficient, a virtual-reality (VR) based training system for the placement of K-wires was developed. As part of this, the current work deals with the real-time bone drilling simulation using a haptic force-feedback device. To simulate the drilling, we introduce a virtual fixture based force-feedback drilling approach. By decomposition of the drilling task into individual phases, each phase can be handled individually to perfectly control the drilling procedure. We report about the related finite state machine (FSM), describe the haptic feedback of each state and explain, how to avoid jerking of the haptic force-feedback during state transition. The usage of the virtual fixture approach results in a good haptic performance and a stable drilling behavior. This was confirmed by 26 expert surgeons, who evaluated the virtual drilling on the simulator and rated it as very realistic. To make the system even more convincing, we determined real drilling feed rates through experimental pig bone drilling and transferred them to our system. Due to a constant simulation thread we can guarantee a precise drilling motion. Virtual fixtures based force-feedback calculation is able to simulate force-feedback assisted bone drilling with high quality and, thus, will have a great potential in developing medical applications. KW - Handchirurgie KW - Osteosynthese KW - Operationstechnik KW - Lernprogramm KW - Virtuelle Realität KW - Medical training system KW - Virtual fixtures KW - Virtual reality KW - Force-feedback haptic KW - Minimally invasive hand surgery KW - K-wire drilling Y1 - 2019 U6 - https://doi.org/10.1016/j.compbiomed.2019.103473 N1 - Corresponding author: Christoph Palm VL - 114 SP - 1 EP - 10 PB - Elsevier ER - TY - JOUR A1 - Rückert, Tobias A1 - Rückert, Daniel A1 - Palm, Christoph T1 - Methods and datasets for segmentation of minimally invasive surgical instruments in endoscopic images and videos: A review of the state of the art JF - Computers in Biology and Medicine N2 - In the field of computer- and robot-assisted minimally invasive surgery, enormous progress has been made in recent years based on the recognition of surgical instruments in endoscopic images and videos. In particular, the determination of the position and type of instruments is of great interest. Current work involves both spatial and temporal information, with the idea that predicting the movement of surgical tools over time may improve the quality of the final segmentations. The provision of publicly available datasets has recently encouraged the development of new methods, mainly based on deep learning. In this review, we identify and characterize datasets used for method development and evaluation and quantify their frequency of use in the literature. We further present an overview of the current state of research regarding the segmentation and tracking of minimally invasive surgical instruments in endoscopic images and videos. The paper focuses on methods that work purely visually, without markers of any kind attached to the instruments, considering both single-frame semantic and instance segmentation approaches, as well as those that incorporate temporal information. The publications analyzed were identified through the platforms Google Scholar, Web of Science, and PubMed. The search terms used were “instrument segmentation”, “instrument tracking”, “surgical tool segmentation”, and “surgical tool tracking”, resulting in a total of 741 articles published between 01/2015 and 07/2023, of which 123 were included using systematic selection criteria. A discussion of the reviewed literature is provided, highlighting existing shortcomings and emphasizing the available potential for future developments. KW - Deep Learning KW - Minimal-invasive Chirurgie KW - Bildsegmentierung KW - Surgical instrument segmentation KW - Surgical instrument tracking KW - Spatio-temporal information KW - Endoscopic surgery KW - Robot-assisted surgery Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-69830 N1 - Corresponding author: Tobias Rückert N1 - Corrigendum unter: https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/7033 VL - 169 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Höng, Simon K. A1 - Wiederer, Jonas A1 - Eder, Friedrich A1 - Obergriesser, Mathias A1 - Linner, Thomas T1 - Towards AI-enhanced facade planning : integrating human expertise with machine learning-driven parametric modeling T2 - EC³ & CIB W78 : 2025 European Conference on Computing in Construction & 42nd CIB W78 IT in Construction Conference N2 - Planning modern facade systems is complex, requiring optimization across multiple domains.This paper proposes an AI-enhanced workflow for facade planning, harnessing computer vision and human input via a Large Language Model.A generative AI system then guides a parametric model to produce 3D facade designs. Automated checks provide feedback to a Reinforcement Learning system, to iteratively determine optimal solutions.These solutions are verified and finalized by human expertise, ensuring improved outcomes with reduce planning time and effort.The approach illustrates how combining advanced AI methods with human expertise can address the multifactorial challenges of facade design within current industry practices. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-84862 SN - 978-9-083451-31-2 SN - 2684-1150 VL - 6 SP - 192 EP - 199 PB - European Council for Computing in Construction ER - TY - JOUR A1 - Maerkl, Raphaela A1 - Rueckert, Tobias A1 - Rauber, David A1 - Gutbrod, Max A1 - Weber Nunes, Danilo A1 - Palm, Christoph T1 - Enhancing generalization in zero-shot multi-label endoscopic instrument classification JF - International Journal of Computer Assisted Radiology and Surgery N2 - Purpose Recognizing previously unseen classes with neural networks is a significant challenge due to their limited generalization capabilities. This issue is particularly critical in safety-critical domains such as medical applications, where accurate classification is essential for reliability and patient safety. Zero-shot learning methods address this challenge by utilizing additional semantic data, with their performance relying heavily on the quality of the generated embeddings. Methods This work investigates the use of full descriptive sentences, generated by a Sentence-BERT model, as class representations, compared to simpler category-based word embeddings derived from a BERT model. Additionally, the impact of z-score normalization as a post-processing step on these embeddings is explored. The proposed approach is evaluated on a multi-label generalized zero-shot learning task, focusing on the recognition of surgical instruments in endoscopic images from minimally invasive cholecystectomies. Results The results demonstrate that combining sentence embeddings and z-score normalization significantly improves model performance. For unseen classes, the AUROC improves from 43.9% to 64.9%, and the multi-label accuracy from 26.1% to 79.5%. Overall performance measured across both seen and unseen classes improves from 49.3% to 64.9% in AUROC and from 37.3% to 65.1% in multi-label accuracy, highlighting the effectiveness of our approach. Conclusion These findings demonstrate that sentence embeddings and z-score normalization can substantially enhance the generalization performance of zero-shot learning models. However, as the study is based on a single dataset, future work should validate the method across diverse datasets and application domains to establish its robustness and broader applicability. KW - Generalized zero-shot learning KW - Sentence embeddings KW - Z-score normalization KW - Multi-label classification KW - Surgical instruments Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-85674 N1 - Corresponding author der OTH Regensburg: Raphaela Maerkl VL - 20 SP - 1577 EP - 1587 PB - Springer Nature ER - TY - JOUR A1 - Esper, Lukas A1 - Schultheiss, Ulrich A1 - Grad, Marius A1 - Noster, Ulf A1 - Bund, Andreas T1 - Application of the Hull Cell for Identifying Electropolishing Parameters to Adjust Surface Morphology in Additive Manufacturing JF - ECS Advances N2 - Additively processed materials are increasingly used to manufacture customized parts, e.g. medical implants. Implant surfaces often require a smooth finish, which can be achieved by post-processing and well-defined process parameters. In this study, the effects of electropolishing of metal parts produced by laser powder bed fusion are investigated using Hull cell experiments and a three-electrode setup. Current density voltage curves were measured with the three-electrode setup to identify the regimes for electropolishing. Subsequently different constant-currents were applied and Hull cell experiments were conducted. The surface roughness (Sz, Sa) and the mass removal were analysed. Surface morphologies were assessed using laser scanning and scanning electron microscopy. A reduction of the initial surface roughness of more than 90% to Sa < 0.3 μm has been achieved. Considering the passed electrical charge during electropolishing, results from Hull cell experiments are systematically correlated with current-controlled electropolishing. This approach enables the precise tailoring of polishing parameters to achieve surfaces with defined roughness. Furthermore, the study demonstrates the suitability of Hull cells in determining electropolishing parameters for additive materials and highlights their contribution to post-processing in additive manufacturing. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-86295 SN - 2754-2734 N1 - Corresponding author der OTH Regensburg: Lukas Esper VL - 4 IS - 4 PB - The Electrochemical Society ER - TY - JOUR A1 - Greiner, Nina A1 - Lauer, Norina A1 - Schedel, Valentin A1 - Pfingsten, Andrea T1 - Group rehabilitation for adults with acquired neurological disorders: A systematic review of mono- and interdisciplinary interventions in physical and speech-language therapy JF - PM&R N2 - Background: Group treatments and interdisciplinary collaboration are recommended in evidence-based guidelines for neurorehabilitation, including physical and speech-language therapy. Evidence suggests that activating overlapping neural networks for upper extremity motor control and speechlanguage processing produces synergistic effects during therapy. This systematic review aims to overview and appraise the efficacy of group treatments in traditional rehabilitation and telerehabilitation. In addition to summarizing evidence on monodisciplinary approaches in physical and speech-language therapy, it seeks data on integrative approaches involving one or both disciplines to inform further interdisciplinary collaboration. Methods: The review was registered with PROSPERO (CRD42021288012) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Systematic searches were conducted in PubMed, CINAHL, and the Cochrane Library. Two reviewers independently screened studies, extracted data, and assessed quality using AMSTAR 2, the Physiotherapy Evidence Database (PEDro) scale, or the Joanna Briggs Institute (JBI) Checklist, as appropriate. The evidence was summarized in a systematic narrative synthesis and its certainty rated based on the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Results: A total of 29 studies were included: 16 on speech-language therapy (861 participants) and 13 on physical therapy (1757 participants). No studies addressed interdisciplinary group interventions, and only two evaluated group telerehabilitation. Outcome domains and measures varied across studies and the certainty of evidence was predominantly low. However, moderate-certainty evidence supports that group speech-language therapy improves quality of life, communication, and language in stroke survivors, especially when interventions emphasize verbal production in communicative settings with multimodal materials and cueing. In physical therapy, circuit class training may be more effective than other group approaches for enhancing quality of life and mobility. Conclusion: Group treatments in neurorehabilitation show some benefits, but further research is needed – especially regarding interdisciplinary approaches and telerehabilitation. KW - Gruppentherapie KW - Logopädie KW - Physiotherapie KW - Neurologie KW - systematic review KW - group treatment KW - interdisciplinary collaboration KW - speech-language therapy KW - physical therapy Y1 - 2025 U6 - https://doi.org/10.1002/pmrj.70006 N1 - Corresponding author der OTH Regensburg: Nina Greiner PB - Wiley ER - TY - JOUR A1 - Barthel, Mareike A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Application of a transformer encoder for the prediction of intra-abdominal pressure JF - Computer Methods in Biomechanics and Biomedical Engineering N2 - Intra-abdominal pressure is a significant physiological parameter influencing spinal stability and pelvic floor health. This study investigates the potential of a transformer encoder model to predict IAP using motion capture data and musculoskeletal modeling. Data from 211 subjects performing walking, fast walking, and running were used to train a transformer encoder. The model showed promising results with an overall Mean Absolute Percentage Error of 13.5% and a Pearson correlation coefficient of 0.85. Predictions for fast walking and running proved to be more challenging compared to walking, which was attributed to the greater variability and complexity of faster movements. KW - Intra-abdominal pressure KW - transformer encoder KW - machine learning KW - motion capture KW - musculoskeletal modeling Y1 - 2025 U6 - https://doi.org/10.1080/10255842.2025.2586143 N1 - Corresponding author der OTH Regensburg: Mareike Barthel PB - Taylor & Francis ER - TY - JOUR A1 - Currle, Edda A1 - Haug, Sonja A1 - Weber, Karsten T1 - Akzeptanz des Einsatzes von Künstlicher Intelligenz im Anamneseprozess: Ergebnisse einer Bevölkerungsbefragung in Deutschland JF - Zeitschrift für Evidenz, Fortbildung und Qualität im Gesundheitswesen N2 - Hintergrund und Zielsetzung Zunehmend werden digitale Anamneseverfahren, wie z. B. Chatbots, entwickelt und evaluiert, sind jedoch in Arztpraxen in Deutschland noch nicht flächendeckend implementiert. Ziel dieser Arbeit ist die Erhebung der Akzeptanz der Bevölkerung in Deutschland gegenüber KI-gestützten Verfahren im Anamneseprozess, durch die es möglich wird, Rückschlüsse auf die Nutzung der Verfahren und ihre Eignung als Bestandteil von Digitalisierungsstrategien der Praxen zu ziehen. Methode Die Studie basiert auf einer Onlinebefragung der Bevölkerung in Deutschland (Feldphase 18.-24.11.2024, n = 1.000). Zurückgehend auf die „Unified Theory of Acceptance and Use of Technology“ (UTAUT) wurden drei zentrale Hypothesen zur Nutzung von Künstlicher Intelligenz (KI) im Anamneseprozess aufgestellt und mit linearen Regressionsmodellen getestet. Ergebnisse Die Akzeptanz für die Nutzung von KI-gestützten Systemen fällt in beiden untersuchten Szenarien, der Nutzung eines Chatbots zu Hause und der Nutzung eines Chatbots in einer Arztpraxis, hoch aus. Dabei bestätigen sich die erwarteten Zusammenhänge von Leistungserwartung, Aufwandserwartung und erwartetem Sozialem Einfluss mit der Verhaltensabsicht, einen Chatbot in der Arztpraxis oder vor dem Besuch einer Arztpraxis zu nutzen. Die Einflüsse von Alter, Geschlecht oder Erfahrung mit der Technologie zeigen jedoch nicht die vermuteten Zusammenhänge. Diskussion und Schlussfolgerung Die Praktikabilität ist von entscheidender Bedeutung für eine positive Einstellung gegenüber der Nutzung. Dabei zeigt sich kein Unterschied zwischen den Geschlechtern. Bei der Implementierung von Chatbots im Anamneseprozess sollten die Aspekte Praktikabilität, Datenschutz und Datensicherheit eine wesentliche Rolle spielen. Angesichts der Tatsache, dass ein großer Teil der älteren Bevölkerung in Deutschland nach wie vor über begrenzte Erfahrung mit digitalen Technologien verfügt, ist Gebrauchstauglichkeit für diese Bevölkerungsgruppe sowie für Menschen mit Beeinträchtigungen von hoher Relevanz. N2 - Background and objectives Digital tools for medical history-taking, such as chatbots, are increasingly being developed and evaluated but have not yet been implemented across the board in medical practices in Germany. The aim of this study was to survey the acceptance of AI-supported tools for medical history-taking among the German population, thereby allowing conclusions to be drawn about the use of these tools and their suitability as part of digitalization strategies in medical practices. Method The study is based on an online survey among the German population (fieldwork November 18 to 24, 2024, n = 1,000). Based on the ‘Unified Theory of Acceptance and Use of Technology’ (UTAUT), three central hypotheses on the use of artificial intelligence (AI) in the medical history-taking process were generated and tested using linear regression models. Results In the two scenarios examined — patients using a chatbot at home and at the doctor’s office — there was a high level of acceptance for the use of AI-supported systems. The expected relationships between Performance Expectancy, Effort Expectancy and expected Social Influence with the behavioral intention to use a chatbot either in the doctor’s office or before visiting the doctor’s office have been confirmed. However, influential factors such as age, gender, or experience with technology do not show the expected correlations. Discussion and conclusion Practicability is crucial for a favorable attitude towards AI applications. There were no apparent gender differences. When implementing chatbots in the medical history-taking process, the aspects of practicability, data protection, and data security should play a key role. Given that a large number of the elderly in Germany still have limited experience with digital technologies, usability is highly relevant for both this population group and for people with disabilities. T2 - Acceptance of artificial intelligence tools for medical history-taking: Findings of a population survey in Germany KW - Künstliche Intelligenz KW - Anamnese KW - Technologieakzeptanz KW - UTAUT KW - Bevölkerungsumfrage Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-86715 N1 - Corresponding author der OTH Regensburg: Edda Currle VL - 198-199 SP - 9 EP - 17 PB - Elsevier ER - TY - JOUR A1 - Weiherer, Maximilian A1 - Eigenberger, Andreas A1 - Egger, Bernhard A1 - Brébant, Vanessa A1 - Prantl, Lukas A1 - Palm, Christoph T1 - Learning the shape of female breasts: an open-access 3D statistical shape model of the female breast built from 110 breast scans JF - The Visual Computer N2 - We present the Regensburg Breast Shape Model (RBSM)—a 3D statistical shape model of the female breast built from 110 breast scans acquired in a standing position, and the first publicly available. Together with the model, a fully automated, pairwise surface registration pipeline used to establish dense correspondence among 3D breast scans is introduced. Our method is computationally efficient and requires only four landmarks to guide the registration process. A major challenge when modeling female breasts from surface-only 3D breast scans is the non-separability of breast and thorax. In order to weaken the strong coupling between breast and surrounding areas, we propose to minimize the variance outside the breast region as much as possible. To achieve this goal, a novel concept called breast probability masks (BPMs) is introduced. A BPM assigns probabilities to each point of a 3D breast scan, telling how likely it is that a particular point belongs to the breast area. During registration, we use BPMs to align the template to the target as accurately as possible inside the breast region and only roughly outside. This simple yet effective strategy significantly reduces the unwanted variance outside the breast region, leading to better statistical shape models in which breast shapes are quite well decoupled from the thorax. The RBSM is thus able to produce a variety of different breast shapes as independently as possible from the shape of the thorax. Our systematic experimental evaluation reveals a generalization ability of 0.17 mm and a specificity of 2.8 mm. To underline the expressiveness of the proposed model, we finally demonstrate in two showcase applications how the RBSM can be used for surgical outcome simulation and the prediction of a missing breast from the remaining one. Our model is available at https://www.rbsm.re-mic.de/. KW - Statistical shape model KW - Non-rigid surface registration KW - Breast imaging KW - Surgical outcome simulation KW - Breast reconstruction surgery Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-30506 N1 - Corresponding author: Christoph Palm N1 - Zugehörige arXiv-Publikation: https://opus4.kobv.de/opus4-oth-regensburg/frontdoor/index/index/docId/2023 VL - 39 IS - 4 SP - 1597 EP - 1616 PB - Springer Nature ER - TY - JOUR A1 - Brébant, Vanessa A1 - Weiherer, Maximilian A1 - Noisser, Vivien A1 - Seitz, Stephan A1 - Prantl, Lukas A1 - Eigenberger, Andreas T1 - Implants Versus Lipograft: Analysis of Long-Term Results Following Congenital Breast Asymmetry Correction JF - Aesthetic Plastic Surgery N2 - Aims Congenital breast asymmetry represents a particular challenge to the classic techniques of plastic surgery given the young age of patients at presentation. This study reviews and compares the long-term results of traditional breast augmentation using silicone implants and the more innovative technique of lipografting. Methods To achieve this, we not only captured subjective parameters such as satisfaction with outcome and symmetry, but also objective parameters including breast vol-ume and anthropometric measurements. The objective examination was performed manually and by using the Vectra H2 photogrammetry scanning system. Results Differences between patients undergoing either implant augmentation or lipograft were revealed not to be significant with respect to patient satisfaction with surgical outcome (p= 0.55) and symmetry (p= 0.69). Furthermore, a breast symmetry of 93 % was reported in both groups. Likewise, no statistically significant volume difference between the left and right breasts was observed in both groups (p\0.41). However, lipograft patients needed on average 2.9 procedures to achieve the desired result, compared with 1.3 for implant augmentation. In contrast, patients treated with implant augmentation may require anumber of implant changes during their lifetime. Conclusion Both methods may be considered for patients presenting with congenital breast asymmetry. KW - Congenital Breast Asymmetry KW - 3D volumetry KW - Autologous fat injections KW - Three-dimensional imaging KW - Lipograft Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-32404 N1 - Corresponding author der OTH Regensburg: Vanessa Brébant VL - 46 SP - 2228 EP - 2236 PB - Springer Nature ER - TY - JOUR A1 - Maier, Johannes A1 - Weiherer, Maximilian A1 - Huber, Michaela A1 - Palm, Christoph T1 - Imitating human soft tissue on basis of a dual-material 3D print using a support-filled metamaterial to provide bimanual haptic for a hand surgery training system JF - Quantitative Imaging in Medicine and Surgery N2 - Background: Currently, it is common practice to use three-dimensional (3D) printers not only for rapid prototyping in the industry, but also in the medical area to create medical applications for training inexperienced surgeons. In a clinical training simulator for minimally invasive bone drilling to fix hand fractures with Kirschner-wires (K-wires), a 3D-printed hand phantom must not only be geometrically but also haptically correct. Due to a limited view during an operation, surgeons need to perfectly localize underlying risk structures only by feeling of specific bony protrusions of the human hand. Methods: The goal of this experiment is to imitate human soft tissue with its haptic and elasticity for a realistic hand phantom fabrication, using only a dual-material 3D printer and support-material-filled metamaterial between skin and bone. We present our workflow to generate lattice structures between hard bone and soft skin with iterative cube edge (CE) or cube face (CF) unit cells. Cuboid and finger shaped sample prints with and without inner hard bone in different lattice thickness are constructed and 3D printed. Results: The most elastic available rubber-like material is too firm to imitate soft tissue. By reducing the amount of rubber in the inner volume through support material (SUP), objects become significantly softer. Without metamaterial, after disintegration, the SUP can be shifted through the volume and thus the body loses its original shape. Although the CE design increases the elasticity, it cannot restore the fabric form. In contrast to CE, the CF design increases not only the elasticity but also guarantees a local limitation of the SUP. Therefore, the body retains its shape and internal bones remain in its intended place. Various unit cell sizes, lattice thickening and skin thickness regulate the rubber material and SUP ratio. Test prints with higher SUP and lower rubber material percentage appear softer and vice versa. This was confirmed by an expert surgeon evaluation. Subjects adjudged pure rubber-like material as too firm and samples only filled with SUP or lattice structure in CE design as not suitable for imitating tissue. 3D-printed finger samples in CF design were rated as realistic compared to the haptic of human tissue with a good palpable bone structure. Conclusions: We developed a new dual-material 3D print technique to imitate soft tissue of the human hand with its haptic properties. Blowy SUP is trapped within a lattice structure to soften rubber-like 3D print material, which makes it possible to reproduce a realistic replica of human hand soft tissue. KW - Dual-material 3D printing KW - Hand surgery training KW - Metamaterial KW - Support material KW - Tissue-imitating hand phantom KW - Handchirurgie KW - 3D-Druck KW - Biomaterial KW - Lernprogramm Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-979 N1 - Corresponding author: Christoph Palm VL - 9 IS - 1 SP - 30 EP - 42 PB - AME Publishing Company ER - TY - JOUR A1 - Maier, Johannes A1 - Weiherer, Maximilian A1 - Huber, Michaela A1 - Palm, Christoph T1 - Optically tracked and 3D printed haptic phantom hand for surgical training system JF - Quantitative Imaging in Medicine and Surgery N2 - Background: For surgical fixation of bone fractures of the human hand, so-called Kirschner-wires (K-wires) are drilled through bone fragments. Due to the minimally invasive drilling procedures without a view of risk structures like vessels and nerves, a thorough training of young surgeons is necessary. For the development of a virtual reality (VR) based training system, a three-dimensional (3D) printed phantom hand is required. To ensure an intuitive operation, this phantom hand has to be realistic in both, its position relative to the driller as well as in its haptic features. The softest 3D printing material available on the market, however, is too hard to imitate human soft tissue. Therefore, a support-material (SUP) filled metamaterial is used to soften the raw material. Realistic haptic features are important to palpate protrusions of the bone to determine the drilling starting point and angle. An optical real-time tracking is used to transfer position and rotation to the training system. Methods: A metamaterial already developed in previous work is further improved by use of a new unit cell. Thus, the amount of SUP within the volume can be increased and the tissue is softened further. In addition, the human anatomy is transferred to the entire hand model. A subcutaneous fat layer and penetration of air through pores into the volume simulate shiftability of skin layers. For optical tracking, a rotationally symmetrical marker attached to the phantom hand with corresponding reference marker is developed. In order to ensure trouble-free position transmission, various types of marker point applications are tested. Results: Several cuboid and forearm sample prints lead to a final 30 centimeter long hand model. The whole haptic phantom could be printed faultless within about 17 hours. The metamaterial consisting of the new unit cell results in an increased SUP share of 4.32%. Validated by an expert surgeon study, this allows in combination with a displacement of the uppermost skin layer a good palpability of the bones. Tracking of the hand marker in dodecahedron design works trouble-free in conjunction with a reference marker attached to the worktop of the training system. Conclusions: In this work, an optically tracked and haptically correct phantom hand was developed using dual-material 3D printing, which can be easily integrated into a surgical training system. KW - Handchirurgie KW - 3D-Druck KW - Lernprogramm KW - Zielverfolgung KW - HaptiVisT KW - Dual-material 3D printing KW - hand surgery training KW - metamaterial KW - tissue imitating phantom hand Y1 - 2020 U6 - https://doi.org/10.21037/qims.2019.12.03 N1 - Corresponding author: Christoph Palm VL - 10 IS - 02 SP - 340 EP - 455 PB - AME Publishing Company CY - Hong Kong, China ER - TY - JOUR A1 - Ebigbo, Alanna A1 - Mendel, Robert A1 - Probst, Andreas A1 - Manzeneder, Johannes A1 - Souza Jr., Luis Antonio de A1 - Papa, João Paulo A1 - Palm, Christoph A1 - Messmann, Helmut T1 - Computer-aided diagnosis using deep learning in the evaluation of early oesophageal adenocarcinoma JF - GuT N2 - Computer-aided diagnosis using deep learning (CAD-DL) may be an instrument to improve endoscopic assessment of Barrett’s oesophagus (BE) and early oesophageal adenocarcinoma (EAC). Based on still images from two databases, the diagnosis of EAC by CAD-DL reached sensitivities/specificities of 97%/88% (Augsburg data) and 92%/100% (Medical Image Computing and Computer-Assisted Intervention [MICCAI] data) for white light (WL) images and 94%/80% for narrow band images (NBI) (Augsburg data), respectively. Tumour margins delineated by experts into images were detected satisfactorily with a Dice coefficient (D) of 0.72. This could be a first step towards CAD-DL for BE assessment. If developed further, it could become a useful adjunctive tool for patient management. KW - Speiseröhrenkrebs KW - Diagnose KW - Computerunterstütztes Verfahren KW - Maschinelles Lernen Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-68 N1 - Corresponding authors: Alanna Ebigbo and Christoph Palm VL - 68 IS - 7 SP - 1143 EP - 1145 PB - British Society of Gastroenterology ER - TY - JOUR A1 - Safi, Hila A1 - Bandic, Medina A1 - Niedermeier, Christoph A1 - Almudever, Carmen G. A1 - Feld, Sebastian A1 - Mauerer, Wolfgang T1 - Stacking the odds: full-stack quantum system design space exploration JF - EPJ Quantum Technology N2 - Design space exploration (DSE) plays an important role in optimising quantum circuit execution by systematically evaluating different configurations of compilation strategies and hardware settings. In this paper, we conduct a comprehensive investigation into the impact of various layout methods, qubit routing techniques, and optimisation levels, as well as device-specific properties such as different variants and strengths of noise and imperfections, the topological structure of qubits, connectivity densities, and back-end sizes. By spanning through these dimensions, we aim to understand the interplay between compilation choices and hardware characteristics. A key question driving our exploration is whether the optimal selection of device parameters, mapping techniques, comprising of initial layout strategies and routing heuristics can mitigate device induced errors beyond standard error mitigation approaches. Our results show that carefully selecting software strategies (e.g., mapping and routing algorithms) and tailoring hardware characteristics (such as minimising noise and leveraging topology and connectivity density) significantly improve the fidelity of circuit execution outcomes, and thus the expected correctness or success probability of the computational result. We provide estimates based on key metrics such as circuit depth, gate count and expected fidelity. Our results highlight the importance of hardware–software co-design, particularly as quantum systems scale to larger dimensions, and along the way towards fully error corrected quantum systems: Our study is based on computationally noisy simulations, but considers various implementations of quantum error correction (QEC) using the same approach as for other algorithms. The observed sensitivity of circuit fidelity to noise and connectivity suggests that co-design principles will be equally critical when integrating QEC in future systems. Our exploration provides practical guidelines for co-optimising physical mapping, qubit routing, and hardware configurations in realistic quantum computing scenarios. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-85157 N1 - Corresponding author der OTH Regensburg: Hila Safi VL - 12 PB - Springer CY - Heidelberg ER - TY - CHAP A1 - Graf, Julian A1 - Hachani, Murad A1 - Fischer, Sebastian A1 - Hackenberg, Rudolf T1 - A heuristic packet processing model for improved encrypted network analysis T2 - CSCS '25: Proceedings of the 2nd Cyber Security in CarS Workshop N2 - Modern networked systems, such as those in the automotive sector, face increasing complexity and growing attack surfaces due to the rise of interconnected and data-driven technologies. Detecting malicious behavior in these environments requires efficient and scalable methods that can operate reliably despite limited resources and high communication volumes. This paper proposes a heuristic packet processing model designed to support intrusion detection based on structural and temporal characteristics of encrypted network traffic. The model follows a modular architecture consisting of four key phases: recording, sorting, prioritizing, and analyzing. At the core of the approach is the Polymetric Queueing Topology Space, a feature space that combines statistical and time series attributes derived from model structure and flow data. These features serve as input for machine learning models, which can effectively distinguish between benign and intrusion traffic patterns without relying on packet data beyond the transport layer. The approach was evaluated using the publicly available ToN_IoT dataset and demonstrated that reliable classification is achievable using a subset of the developed feature space that contains model-derived traffic features. We used Random Forest for supervised binary and multi-class classification achieving high accuracy scores of 99% for binary and 98% for multi-class classification. Additionally, for unsupervised anomaly detection, we created an Isolation Forest model accomplishing F1-scores of 0.92 for the benign and 0.96 for intrusion class. The architecture is designed to enable dynamic traffic prioritization and to offer a flexible foundation that can observe diverse network domains while maintaining efficient performance under constrained computational conditions. Y1 - 2025 U6 - https://doi.org/10.1145/3736130.3764510 PB - ACM CY - New York, USA ER - TY - JOUR A1 - Heberl, Michael A1 - Hofrichter, Andreas A1 - Rank, Daniel A1 - Bauer, Franz A1 - Sterner, Michael T1 - Influence of plant dimensioning and location on the ecology of PEM electrolysis JF - International Journal of Hydrogen Energy N2 - PV and wind systems with PEM electrolysis offer great potential for producing hydrogen with low emissions. Our research has identified the ecologically optimal size of PEM in relation to fixed PV/wind capacities. We calculate efficiencies and production volumes for PEM with 240 capacity and site variations. We analyse the global warming potential of all systems and draw conclusions about the optimal system design. The lowest GWP is achieved at the site with the highest full load hours with 1.32 kg CO2-eq/kg H2 (Wind, 28 MW electrolysis) and 4.24 kg CO2-eq/kg H2 (PV, 23 MW electrolysis). We have identified a clear trend: increasing PV/wind full load hours leads to higher ideal PEM capacities. However, there is a significant discrepancy between the ideal economic and ecological capacity. Furthermore, higher electrolysis capacities can achieve lower emissions as they increasingly operate at a more efficient partial load. KW - Electrolysis KW - Life cycle analysis KW - Global warming potential KW - Plant design KW - Renewable energy Y1 - 2025 U6 - https://doi.org/10.1016/j.ijhydene.2025.151039 SN - 0360-3199 VL - 167 PB - Elsevier ER - TY - CHAP A1 - Stocker, Philipp A1 - Lehrer, Tobias A1 - Duddeck, Fabian A1 - Wagner, Marcus T1 - Face-wise prediction of sheet-metal drawability using graph neural networks T2 - Journal of Physics: Conference Series N2 - The early design phase of deep-drawn structural components involves time-consuming iterative development. Traditional drawability assessments rely on finite element simulations, which are computationally expensive and slow the design process. Alternative machine learning (ML) approaches show promise in accelerating this process but face challenges with existing methods. Existing low-dimensional ML models only provide global predictions without identifying specific geometric regions prone to failure. High-dimensional models provide local predictions but require significant amounts of training data. We propose a data-driven approach leveraging graph neural networks (GNNs) for face-wise drawability prediction of sheet metal components in their computer-aided design (CAD) representation. Our method aims to bridge the gap between the computational efficiency of ML and the spatial resolution of simulation by providing face-wise insight into potential failure regions. This study utilises a dataset of parametric U-channel geometries with variability in both geometry and topology. Ground-truth labels are generated using inverse analysis simulations. Geometric entities are represented through the use of UV parameterisations, whereby 3D surfaces are mapped into 2D space to facilitate geometric encoding. Concurrently, the topological relationships are captured using a face adjacency graph. To address data scarcity, we evaluate how different amounts of training data affect model performance and perform ablation studies to analyse the impact of different CAD representation features. Our results show that the proposed approach achieves high accuracy even with limited training data. In addition, the ablation studies provide insights into the most critical CAD features, guiding future research. These results highlight the potential of our GNN to predict face-wise drawability in the early design phase. Y1 - 2025 U6 - https://doi.org/10.1088/1742-6596/3104/1/012053 SN - 1742-6588 N1 - Corresponding author der OTH Regensburg: Philipp Stocker VL - 3104 IS - 1 PB - IOP Publishing ER - TY - JOUR A1 - Hantsch, Carolin A1 - Westner, Markus A1 - Matschi, Markus T1 - IT/OT-Konvergenz: Status-Quo und Umsetzungsempfehlungen JF - HMD Praxis der Wirtschaftsinformatik N2 - Organisationen machen große Anstrengungen zur Verbesserung ihrer Ambidextrie, d. h. ihrer Fähigkeit sowohl Exploitationsziele (z. B. Effizienz, Vorhersagbarkeit) als auch Explorationsziele (z. B. Anpassbarkeit, Innovation) zu erreichen. Obwohl gemäß der Praxisliteratur Technologie in Software-Projekten dabei eine zentrale Rolle spielen kann, gibt es kaum Forschung dazu, wie technologische Faktoren Ambidexterie in Software-Projekten beeinflussen. In dieser Studie untersuchen wir die Rolle dreier technologischer Faktoren: kontinuierliche Integration, Standardisierung und Microservice-Architektur. Die Ergebnisse einer Mehrinformanten-Umfrage in 95 Projekten in der Schweiz und Dänemark zeigen, dass kontinuierliche Integration und Standardisierung mit höherer Ambidexterie einhergehen, während der Zusammenhang zwischen Microservice-Architektur und Ambidextrie nicht signifikant ist. Unser Artikel geht über die existierende Forschung hinaus, indem er zeigt, dass kontinuierliche Integration und Standardisierung nicht nur Exploitation, sondern auch Exploration fördern können. Wir diskutieren auch Gründe für den insignifikanten Zusammenhang zwischen Microservice-Architektur und Ambidextrie. N2 - This study examines IT/OT Convergence in 31 predominantly large German companies. It presents an “IT/OT Governance Framework” as a specific model for successful convergence implementation. The analysis reveals a heterogeneous level of convergence maturity across the examined companies, the majority of which are at the beginning or in the implementation phase. Close cooperation between IT and OT is favored, but without IT completely taking over OT. An IT/OT tandem consisting of a CIO and a central OT responsible person is seen as the ideal way to take responsibility. Six specific recommendations were derived from the interviews and included in the IT/OT Governance Framework developed. These include ensuring top management support, using security as a driver, introducing a central OT responsible person, bringing IT and OT teams physically closer together, continuously demonstrating the added value of convergence, and taking a step-by-step approach to implementation. KW - IT/OT Convergence KW - Operational Technology KW - OT KW - Governance Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-77937 N1 - Corresponding author der OTH Regensburg: Markus Westner PB - Springer Nature ER - TY - JOUR A1 - Schmid, Michael T. A1 - Thiel, Charlotte T1 - Is it worth it? Potential for reducing the environmental impact of bitumen roofing membrane production JF - Recycling N2 - Between 51% and 72% of a bituminous roofing membrane used for structural water-proofing consists of organic material, predominantly bitumen - a derivative of crude oil refining - highlighting the strong dependence of this product on fossil resources. Considering that several tonnes of these membranes must be replaced every 30 to 50 years, substantial potential exists for emission reduction through the establishment of circular material systems. This study investigates this potential by analysing 26 Environmental Product Declarations (EPDs) and life cycle datasets from across Europe covering the period from 2007 to 2023. To ensure comparability, all data were normalised to a declared unit of 1 kg of roofing membrane. The reinforcement layers were categorised into glass and polyester & glass composites, and their differences were examined using Welch’s t-tests. Correlative analyses and linear as well as multiple regression models were then applied to explore relationships between environmental indicators and the shares of organic and mineral mass fractions. The findings reveal that renewable energy sources, although currently representing only a small share of total production energy, provide a major lever for reducing nearly all environmental impact categories. The type of reinforcement layer was also found to influence the demand for fossil resources, both materially and energetically. For most environmental indicators, only multiple regression models can explain at least 30% of the variance based on the proportions of organic and mineral inputs. Overall, the study underscores the crucial importance of high-quality, transparently documented product data for accurately assessing the sustainability of building products. It further demonstrates that substituting fossil energy carriers with renewable sources and optimising material efficiency can substantially reduce environmental burdens, provided that methodological consistency and clarity of indicator definitions are maintained. KW - bitumen sealing KW - bitumen recycling KW - circular construction KW - correlation analysis KW - LCA Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-86873 N1 - Corresponding author der OTH Regensburg: Michael Schmid VL - 10 IS - 6 PB - MDPI ER - TY - JOUR A1 - Bedbur, Stefan A1 - Kamps, Udo A1 - Schmiedt, Anja Bettina T1 - A flexible model of ordered random variables for non-metallic inclusions in steels and related statistical inference JF - Applied Mathematical Modelling N2 - In a data set of non-metallic inclusion sizes in samples from engineering steel, common order statistics fail to serve as a suitable model for ascendingly ordered measurements within single samples. Therefore, a flexible model of ordered random variables is proposed, which allows for changes of distributions described by model parameters. Joint maximum likelihood estimation of these parameters and the shape parameter of an underlying left-truncated Weibull distribution is considered, and a model test is developed for the null-hypothesis of common order statistics being an adequate model. To overcome small data situations, a link-function approach is examined in order to reduce the number of involved model parameters as well as to propose to use a link-function parameter as a material indicator. An asymptotic test is provided to check for the presence of a linear link function, and tests for hypotheses about two link-function parameters are studied. Moreover, the construction of simultaneous confidence regions for the link-function parameters as well as of confidence bands for the entire graph of the link function are presented. Throughout, the findings are applied to the real metallurgical data set. Similar problems and data structures arise in other fields of material science and applications such as geology. Y1 - 2026 U6 - https://doi.org/10.1016/j.apm.2025.116284 SN - 0307-904X N1 - Corresponding author der OTH Regensburg: Anja Bettina Schmiedt VL - 149 PB - Elsevier ER - TY - JOUR A1 - Schumm, Leon A1 - Brown, Tom A1 - Abdel-Khalek, Hazem A1 - Ueckerdt, Falko A1 - Sterner, Michael A1 - Fioriti, David A1 - Parzen, Max T1 - The impact of temporal hydrogen regulation on hydrogen exporters and their domestic energy transition JF - Nature Communications N2 - As global demand for green hydrogen rises, potential hydrogen exporters move into the spotlight. While exports can bring countries revenue, large-scale on-grid hydrogen electrolysis for export can profoundly impact domestic energy prices and energy-related emissions. Our investigation explores the interplay of hydrogen exports, domestic energy transition and temporal hydrogen regulation, employing a sector-coupled energy model in Morocco. We find substantial co-benefits of domestic carbon dioxide mitigation and hydrogen exports, whereby exports can reduce market-based costs for domestic electricity consumers while mitigation reduces costs for hydrogen exporters. However, increasing hydrogen exports in a fossil-dominated system can substantially raise market-based costs for domestic electricity consumers, but surprisingly, temporal matching of hydrogen production can lower these costs by up to 31% with minimal impact on exporters. Here, we show that this policy instrument can steer the welfare (re-)distribution between hydrogen exporting firms, hydrogen importers, and domestic electricity consumers and hereby increases acceptance among actors. KW - Energy Transition KW - Hydrogen regulation Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-84857 N1 - Die Preprint-Version ist ebenfalls in diesem Repositorium verzeichnet unter: https://opus4.kobv.de/opus4-oth-regensburg/7272 VL - 16 PB - Nature CY - London ER - TY - JOUR A1 - Schmiedt, Anja B. A1 - Empacher, Christina A1 - Kamps, Udo T1 - One- and two-sided prediction intervals for future Pareto record values with applications JF - Journal of Statistical Theory and Applications N2 - Based on upper record values in a series of observations over time from a Pareto distribution, an exact and several approximate one-sided and two-sided prediction intervals for the next record value (or for another future record value) to appear are studied and compared by means of an extensive simulation study. The performances of the prediction intervals are evaluated and recommendations are proposed for what method should be used in a given situation with respect to the form of the prediction interval on the one hand and to the tail behaviour on the other. The proposed methods are applied to insurance, environmental and sports data, where the respectively fitted Pareto distributions show a different tail behaviour. As a result, it is seen that although the number of observed record values in the presented real data applications is rather small, as it is usually the case, the selected prediction intervals are of practical use. KW - Interval prediction KW - Pareto distribution KW - Real data analyses KW - Record values KW - Simulation study Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-81605 SN - 2214-1766 N1 - Corresponding author der OTH Regensburg: Anja B. Schmiedt PB - Springer ER - TY - JOUR A1 - Dotter, Caroline A1 - Haug, Sonja A1 - Schnell, Rainer A1 - Raptis, Georgios A1 - Weber, Karsten T1 - Sharing health data for research purposes: results of a population survey in Germany JF - BMC health services research N2 - BACKGROUND: Increased use of health data has the potential to improve both health care and health policies. Several recent policy initiatives at the European and German legislative levels aim to increase the primary and secondary use of health data. However, little is known about general population views on health data access for research. Most studies are based on subsets defined by specific illnesses. METHODS: We commissioned a national computer-assisted dual-frame telephone survey (landline and mobile). Logit estimation models were used to identify predictors of willingness to provide access to health data to different organizations (universities in Germany, universities worldwide, German government organizations, pharmaceutical companies). RESULTS: A high willingness to share health data for research purposes is observed, depending on the specific data recipient. The willingness is highest for research at universities in Germany and German governmental organizations, and lowest regarding research by pharmaceutical companies. The main drivers for sharing health data are the level of trust in public institutions, the respondents' assessment of the seriousness and likelihood of data misuse, and the level of digital literacy. Age, gender, and level of education have small effects and do not determine the willingness to share health data for all organizations. CONCLUSION: We present evidence from a random sample of the German population. The results indicate widespread support among the population for providing access to health data for research purposes. Similar to findings in other countries, the willingness depends strongly on the recipient of the data. This paper evaluates the impact of various determinants - identified in previous qualitative and quantitative research - on the willingness of the German population to share health data. While previous studies have found that patients are generally more willing to share health data, we found that the presence of a medical precondition does not translate into respondents' unequivocal support for health data sharing. We identify privacy concerns, general trust, and digital literacy as key factors influencing the willingness to share health data. Therefore, policymakers and stakeholders need to ensure and communicate the necessary privacy protection measures to increase the willingness of the German population to share health data. Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-81622 N1 - Corresponding author der OTH Regensburg: Caroline Dotter VL - 25 PB - BMC ER - TY - CHAP A1 - Bugl, Benedikt A1 - Schneider, Viola I. A1 - Sehr, Armin T1 - Vertical Sound Localization: Precision and Robustness to Reverberation in a Large-Scale Study T2 - Proceedings of the 11th Convention of the European Acoustics Association Forum Acusticum / EuroNoise 2025 // Málaga, Spain ; 23-26. June 2025 N2 - Vertical sound localization, the ability to perceive the elevation of a sound source, is a fundamental aspect of human auditory perception, yet it remains far less understood than horizontal localization. Existing studies rely on small sample sizes, limiting the generalizability of findings. The presented study bridges that gap by examining vertical sound localization and precision in a cohort exceeding 150 participants, making it the largest investigation of its kind to date.Participants were exposed to broadband noise stimuli from various elevations under controlled anechoic conditions. The elevation localization error was measured by comparing perceived sound source elevations to actual positions of speakers of a curved array. Azimuth angles of arrival were altered between 0°, 45° and 90°. For a small group the experiment was repeated in echoic conditions, to gain insight in reverberation and reflection robustness of vertical sound localization.This large-scale study establishes benchmarks for vertical sound localization precision and robustness, advancing our understanding of human auditory spatial perception. These findings have implications for audio technology development, such as spatial audio rendering and hearing aid design, and lay the groundwork for further exploration into the neural and anatomical underpinnings of vertical localization. Y1 - 2025 SN - 978-84-87985-35-5 U6 - https://doi.org/10.61782/fa.2025.0953 SP - 3431 EP - 3434 PB - European Acoustics Association ER - TY - CHAP A1 - Galka, Stefan A1 - Meißner, Sebastian T1 - Simulation-Based Digital Twins for Internal Transport Systems T2 - Procedia Computer Science N2 - The increasing complexity of internal transport systems in industrial applications poses significant challenges for operational decision-making. This paper presents a simulation-based Digital Twin framework developed within the research project TwinTraSys to support the control of such systems. The framework is specifically tailored to the constraints of real-world IT infrastructures, requiring minimal transaction data, while enabling predictive analysis and dynamic scenario evaluation. It consists of a modular architecture divided into four core components: data provision, data preparation, simulation, and decision support. A dedicated simulation framework enables the automated generation of structural models and the integration of real-world operational control systems. The proposed approach has been validated in industrial settings and has demonstrated its ability to support resource planning and transport resource allocation through simulation-based experimentation and multi-criteria evaluation. This paper contributes to the practical advancement of Digital Twin applications in intralogistics by bridging the gap between theoretical models and real-world constraints. KW - Digital Twin KW - Intralogistics KW - Logistics KW - Operational Control KW - Simulation KW - Simulation-based Decision Support Y1 - 2025 U6 - https://doi.org/10.1016/j.procs.2025.12.016 N1 - Corresponding author der OTH Regensburg: Stefan Galka VL - 274 SP - 161 EP - 170 PB - Elsevier ER - TY - JOUR A1 - Afanasev, Anna A1 - Höfer, Philipp A1 - Holtmannspötter, Jens A1 - Zimmer, Felix A1 - Ehrlich, Ingo T1 - Development of a continuous fiber-reinforced 3D printing process with a 6-axis robot arm: Process design and equipment JF - The International Journal of Advanced Manufacturing Technology N2 - The utilisation of 3D printing processes in the fabrication of continuous fiber-reinforced composites confers a multitude of advantages, in particular flexible design based on structural requirements. In order to achieve greater flexibility, there is a necessity for 3D printing systems that allow for customisable material selection and fiber positioning. This paper presents the design of a robot-based 3D printing system that incorporates an in-situ impregnation line and flexibility regarding the machine code generation for fiber positioning. The development of the system enabled the attainment of an average fiber volume content of up to 37.12%. In the tensile tests, material characteristics up to E1 = 24.7 GPa and strength of up to RM1 = 0.51 GPa were determined. Y1 - 2026 U6 - https://doi.org/10.1007/s00170-025-17263-3 SN - 0268-3768 N1 - Corresponding author der OTH Regensburg: Anna Afanasev PB - Springer ER - TY - JOUR A1 - Wolfgramm, Alex A1 - Abb, Valerius A1 - Samp, Artur A1 - Samp, Rafal A1 - Hoffmann, Jens Christoph A1 - Müller, Rainer A1 - Kammler, Martin T1 - Structural and functional evolution of HKUST-1 nanoparticles induced by ball milling JF - Next Materials N2 - In this study, the effect of post-synthetic ball milling on the structural and functional properties of as-synthesized nanoparticles of the copper-based metal-organic framework (MOF) HKUST-1 was investigated for the first time. Nanoparticles were synthesized using sodium formate as a capping agent. The crystalline particles were subjected to a controlled ball milling process, which induced significant structural changes. Powder X-ray diffraction (PXRD) revealed a reduction in crystallite size from 91 nm to 21 nm and the introduction of microstrain, partially disrupting the MOF's long-range crystalline order, as evidenced by peak broadening and the diminished intensity of high-angle reflections. Particle morphology pre- and post-milling was further studied with scanning electron microscopy (SEM) imaging, verifying a narrow particle size distribution of ± 22 nm after milling. Fourier-transform infrared spectroscopy (FTIR) indicated protonation of carboxylate groups in the larger pores of the framework, likely due to moisture incorporation during milling. Brunauer-Emmett-Teller (BET) surface area analysis showed a substantial decrease in specific surface area from 521 m²/g to 226 m²/g, suggesting a partial collapse of the porous framework. We discuss the applicability of ball milling as a versatile means of post-synthetic approach to reduce MOF particle sizes, a key element in the preparation of MOF-based thin films using inks or polymers. KW - Ball milling KW - Copper-based metal-organic framework KW - HKUST-1 KW - Nitrogen adsorption Y1 - 2026 U6 - https://doi.org/10.1016/j.nxmate.2025.101544 N1 - Corresponding author der OTH Regensburg: Alex Wolfgramm VL - 10 PB - Elsevier ER - TY - JOUR A1 - Schumm, Leon A1 - Haas, Jannik A1 - Peer, Rebecca A1 - Sterner, Michael T1 - The role of hydrogen offtaker regulation in highly renewable electricity systems JF - Energy N2 - The growing demand for green hydrogen necessitates a rapid scale-up of production and exports to meet decarbonization targets globally. However, current ramp-up efforts remain insufficient, calling for policies that unlock the potential of hydrogen as a low-carbon energy carrier. A key lever is the offtaker regulation, which impacts the pace and sustainability of export projects. This study investigates minimum renewable share requirements for hydrogen exports in countries with high renewable electricity shares. Using New Zealand as a case study, we develop a fully sector-coupled capacity expansion and dispatch model, integrating hydrogen and electricity network planning based on PyPSA-Earth. The model optimizes New Zealand’s energy system under varying export scenarios, renewable electricity shares, and resulting system impacts. We find that domestic electricity demand and renewable expansion rates dominate long-term outcomes, while progressive regulation enables short-term hydrogen and Power-to-X exports. Relaxing the renewable threshold from 80% to 60% triples export volumes from 2.5 TWh to 8.2 TWh by 2030. We propose a two-stage requirement: an initially progressive threshold to attract investment with low consequential emissions, followed by stricter regulation to prevent high emissions, rising domestic electricity prices, and declining hydrogen competitiveness. This framework, demonstrated for New Zealand, can guide hydrogen-exporting countries worldwide. KW - Climate neutrality KW - e-fuels KW - Emission intensity KW - Energy systems modelling KW - Hydrogen exports KW - Hydrogen offtaker regulation KW - Power-to-X Y1 - 2026 U6 - https://doi.org/10.1016/j.energy.2025.139513 N1 - Corresponding author der OTH Regensburg: Leon Schumm VL - 342 PB - Elsevier ER - TY - JOUR A1 - Heinz, Florian A1 - Schildgen, Johannes T1 - Experience Report: Hey LLM, Generate SQL! JF - Datenbank-Spektrum N2 - Large Language Models have advanced to a resourceful tool with many applications. One particularly interesting use case is the LLM-aided generation of ad-hoc database queries and the possibility of subsequent processing of the results in a way suiting the users intents. In this article, practical ways and experiences are described on how to effectively use LLMs to map a natural-language user query to an SQL query conforming to a specific database schema and post-processing the results of this query in order to, for example, create an appealing visualization. Best results are achieved under favorable circumstances, as, for example, a clean and meaningful named database schema. Y1 - 2025 U6 - https://doi.org/10.1007/s13222-025-00512-w N1 - Corresponding author der OTH Regensburg: Florian Heinz VL - 25 IS - 2 SP - 95 EP - 101 PB - Springer CY - Wiesbaden ER -