@inproceedings{43228, abstract = {{The computation of electron repulsion integrals (ERIs) over Gaussian-type orbitals (GTOs) is a challenging problem in quantum-mechanics-based atomistic simulations. In practical simulations, several trillions of ERIs may have to be computed for every time step. In this work, we investigate FPGAs as accelerators for the ERI computation. We use template parameters, here within the Intel oneAPI tool flow, to create customized designs for 256 different ERI quartet classes, based on their orbitals. To maximize data reuse, all intermediates are buffered in FPGA on-chip memory with customized layout. The pre-calculation of intermediates also helps to overcome data dependencies caused by multi-dimensional recurrence relations. The involved loop structures are partially or even fully unrolled for high throughput of FPGA kernels. Furthermore, a lossy compression algorithm utilizing arbitrary bitwidth integers is integrated in the FPGA kernels. To our best knowledge, this is the first work on ERI computation on FPGAs that supports more than just the single most basic quartet class. Also, the integration of ERI computation and compression it a novelty that is not even covered by CPU or GPU libraries so far. Our evaluation shows that using 16-bit integer for the ERI compression, the fastest FPGA kernels exceed the performance of 10 GERIS ($10 \times 10^9$ ERIs per second) on one Intel Stratix 10 GX 2800 FPGA, with maximum absolute errors around $10^{-7}$ - $10^{-5}$ Hartree. The measured throughput can be accurately explained by a performance model. The FPGA kernels deployed on 2 FPGAs outperform similar computations using the widely used libint reference on a two-socket server with 40 Xeon Gold 6148 CPU cores of the same process technology by factors up to 6.0x and on a new two-socket server with 128 EPYC 7713 CPU cores by up to 1.9x.}}, author = {{Wu, Xin and Kenter, Tobias and Schade, Robert and Kühne, Thomas and Plessl, Christian}}, booktitle = {{2023 IEEE 31st Annual International Symposium on Field-Programmable Custom Computing Machines (FCCM)}}, pages = {{162--173}}, title = {{{Computing and Compressing Electron Repulsion Integrals on FPGAs}}}, doi = {{10.1109/FCCM57271.2023.00026}}, year = {{2023}}, } @article{45361, abstract = {{ The non-orthogonal local submatrix method applied to electronic structure–based molecular dynamics simulations is shown to exceed 1.1 EFLOP/s in FP16/FP32-mixed floating-point arithmetic when using 4400 NVIDIA A100 GPUs of the Perlmutter system. This is enabled by a modification of the original method that pushes the sustained fraction of the peak performance to about 80%. Example calculations are performed for SARS-CoV-2 spike proteins with up to 83 million atoms. }}, author = {{Schade, Robert and Kenter, Tobias and Elgabarty, Hossam and Lass, Michael and Kühne, Thomas and Plessl, Christian}}, issn = {{1094-3420}}, journal = {{The International Journal of High Performance Computing Applications}}, keywords = {{Hardware and Architecture, Theoretical Computer Science, Software}}, publisher = {{SAGE Publications}}, title = {{{Breaking the exascale barrier for the electronic structure problem in ab-initio molecular dynamics}}}, doi = {{10.1177/10943420231177631}}, year = {{2023}}, } @inproceedings{45661, abstract = {{Effect chain modelling is a method for creating information models for impact analyses of changes in system elements. For the estimation of change propagation, dependencies between requirements must be detected. The high number of require- ment dependencies in the engineering of complex technical systems results in the need for automation. In a study, it was shown that transformer models (BERT) are suitable for the automated dependency analysis of requirements. However, there are currently deficits in the applicability of the models for different projects without an extensive and heterogeneous training database. This paper investigates how active learning can be used to train BERT models (active-BERT) in order to increase the performance of the models for classifying requi- rement dependencies of projects with heterogeneous require- ments. The results show that the performance of the models increases significantly through active learning. Through active- BERT, engineers are enabled to model effect chains efficiently and to handle requirement changes effectively.}}, author = {{Gräßler, Iris and Preuß, Daniel}}, booktitle = {{Stuttgarter Symposium für Produktentwicklung SSP 2023}}, editor = {{Hölzle, Katharina and Kreimeyer, Matthias and Roth, Daniel and Maier, Thomas and Riedel, Oliver}}, issn = {{2364-4885}}, location = {{Stuttgart}}, publisher = {{Fraunhofer IAO}}, title = {{{Automatisierte Abhängigkeitsanalyse von Anforderungen zur Wirkkettenmodellierung}}}, year = {{2023}}, } @article{29240, abstract = {{The principle of least action is one of the most fundamental physical principle. It says that among all possible motions connecting two points in a phase space, the system will exhibit those motions which extremise an action functional. Many qualitative features of dynamical systems, such as the presence of conservation laws and energy balance equations, are related to the existence of an action functional. Incorporating variational structure into learning algorithms for dynamical systems is, therefore, crucial in order to make sure that the learned model shares important features with the exact physical system. In this paper we show how to incorporate variational principles into trajectory predictions of learned dynamical systems. The novelty of this work is that (1) our technique relies only on discrete position data of observed trajectories. Velocities or conjugate momenta do not need to be observed or approximated and no prior knowledge about the form of the variational principle is assumed. Instead, they are recovered using backward error analysis. (2) Moreover, our technique compensates discretisation errors when trajectories are computed from the learned system. This is important when moderate to large step-sizes are used and high accuracy is required. For this, we introduce and rigorously analyse the concept of inverse modified Lagrangians by developing an inverse version of variational backward error analysis. (3) Finally, we introduce a method to perform system identification from position observations only, based on variational backward error analysis.}}, author = {{Ober-Blöbaum, Sina and Offen, Christian}}, issn = {{0377-0427}}, journal = {{Journal of Computational and Applied Mathematics}}, keywords = {{Lagrangian learning, variational backward error analysis, modified Lagrangian, variational integrators, physics informed learning}}, pages = {{114780}}, publisher = {{Elsevier}}, title = {{{Variational Learning of Euler–Lagrange Dynamics from Data}}}, doi = {{10.1016/j.cam.2022.114780}}, volume = {{421}}, year = {{2023}}, } @article{29236, abstract = {{The numerical solution of an ordinary differential equation can be interpreted as the exact solution of a nearby modified equation. Investigating the behaviour of numerical solutions by analysing the modified equation is known as backward error analysis. If the original and modified equation share structural properties, then the exact and approximate solution share geometric features such as the existence of conserved quantities. Conjugate symplectic methods preserve a modified symplectic form and a modified Hamiltonian when applied to a Hamiltonian system. We show how a blended version of variational and symplectic techniques can be used to compute modified symplectic and Hamiltonian structures. In contrast to other approaches, our backward error analysis method does not rely on an ansatz but computes the structures systematically, provided that a variational formulation of the method is known. The technique is illustrated on the example of symmetric linear multistep methods with matrix coefficients.}}, author = {{McLachlan, Robert and Offen, Christian}}, journal = {{Journal of Geometric Mechanics}}, keywords = {{variational integrators, backward error analysis, Euler--Lagrange equations, multistep methods, conjugate symplectic methods}}, number = {{1}}, pages = {{98--115}}, publisher = {{AIMS Press}}, title = {{{Backward error analysis for conjugate symplectic methods}}}, doi = {{10.3934/jgm.2023005}}, volume = {{15}}, year = {{2023}}, } @inproceedings{46502, author = {{Gräßler, Iris and Wiechel, Dominik}}, booktitle = {{2023 18th Annual System of Systems Engineering Conference (SoSe)}}, location = {{Lille}}, publisher = {{IEEE}}, title = {{{Customized impact analyses for technical engineering changes}}}, doi = {{10.1109/sose59841.2023.10178484}}, year = {{2023}}, } @article{46503, abstract = {{ Purpose The purpose of this study is to investigate the manufacturability of Fe-3Si lattice structures and the resulting mechanical properties. This study could lead to the successful processing of squirrel cage conductors (a lattice structure by design) of an induction motor by additive manufacturing in the future. Design/methodology/approach The compression behaviour of two lattice structures where struts are arranged in a face-centred cubic position and vertical edges (FCCZ), and struts are placed at body-centred cubic (BCC) positions, prepared by laser powder bed fusion (LPBF), is explored. The experimental investigations are supported by finite element method (FEM) simulations. Findings The FCCZ lattice structure presents a peak in the stress-strain curve, whereas the BCC lattice structure manifests a plateau. The vertical struts aligned along the compression direction lead to a significant increase in the load-carrying ability of FCCZ lattice structures compared to BCC lattice structures. This results in a peak in the stress-strain curve. However, the BCC lattice structure presents the bending of struts with diagonal struts carrying the major loads with struts near the faceplate receiving the least load. A high concentration of geometrically necessary dislocations (GNDs) near the grain boundaries along cell formation is observed in the microstructure. Originality/value To the best of the authors’ knowledge, this is the first study on additive manufacturing of Fe-3Si lattice structures. Currently, there are no investigations in the literature on the manufacturability and mechanical properties of Fe-3Si lattice structures. }}, author = {{Pramanik, Sudipta and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{1355-2546}}, journal = {{Rapid Prototyping Journal}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}}, number = {{6}}, pages = {{1257--1269}}, publisher = {{Emerald}}, title = {{{Experimental and finite element method investigation on the compression behaviour of FCCZ and BCC lattice structures of additively manufactured Fe-3Si samples}}}, doi = {{10.1108/rpj-06-2022-0190}}, volume = {{29}}, year = {{2023}}, } @article{46507, author = {{Pramanik, Sudipta and Milaege, Dennis and Hein, Maxwell and Andreiev, Anatolii and Schaper, Mirko and Hoyer, Kay-Peter}}, issn = {{1438-1656}}, journal = {{Advanced Engineering Materials}}, keywords = {{Condensed Matter Physics, General Materials Science}}, number = {{14}}, publisher = {{Wiley}}, title = {{{An Experimental and Computational Modeling Study on Additively Manufactured Micro‐Architectured Ti–24Nb–4Zr–8Sn Hollow‐Strut Lattice Structures}}}, doi = {{10.1002/adem.202201850}}, volume = {{25}}, year = {{2023}}, } @article{45602, author = {{Karakaya, Yasin and Somnitz, H. and Hermsen, A. and Gonchikzhapov, Munko and Kasper, Tina}}, issn = {{2666-352X}}, journal = {{Applications in Energy and Combustion Science}}, keywords = {{Metastable particles, Nanomaterials, Quartz-crystal-microbalance, Molecular-beam mass spectrometry, Tetramethylsilane, Reaction kinetics}}, publisher = {{Elsevier BV}}, title = {{{Revisiting the initial reaction rates for TMS combustion and a new evidence for metastable silica nanoparticles in the gas-phase synthesis}}}, doi = {{10.1016/j.jaecs.2023.100152}}, volume = {{14}}, year = {{2023}}, } @inbook{46691, author = {{Dahms, Frederik and Homberg, Werner}}, booktitle = {{Lecture Notes in Mechanical Engineering}}, isbn = {{9783031410222}}, issn = {{2195-4356}}, location = {{Cannes, France}}, publisher = {{Springer Nature Switzerland}}, title = {{{Analysis and Modelling of the Deformation in the Manufacture of Flange-Contours by the Combined Friction-Spinning and Flow-Forming Process}}}, doi = {{10.1007/978-3-031-41023-9_72}}, year = {{2023}}, } @inproceedings{46762, author = {{Tchomgue Simeu, Arnold and Mahnken, Rolf}}, booktitle = {{XI International Conference on Adaptive Modeling and Simulation}}, publisher = {{CIMNE}}, title = {{{Mesh- and model adaptivity for elasto-plastic mean-field and full-field homogenization based on downwind and upwind approximations}}}, doi = {{10.23967/admos.2023.054}}, year = {{2023}}, } @article{46736, author = {{Pfister, Daniel and Jackson, Robin C and Güldenpenning, Iris and Williams, A Mark}}, journal = {{Human Movement Science}}, pages = {{103092}}, publisher = {{Elsevier}}, title = {{{Timing a fake punch: Inhibitory effects in a boxing-specific spatial attention task}}}, doi = {{https://doi.org/10.1016/j.humov.2023.103092}}, volume = {{89}}, year = {{2023}}, } @article{46815, abstract = {{In this work, the influence of the filler–matrix adhesion on the tensile properties of laser-sintered parts built with Polyamide 613 filled with glass beads was investigated. For this purpose, dry blends of glass beads with and without organosilane coupling agents and polyamide powder were prepared and processed into tensile specimens on an EOS P396 laser sintering system. The samples were tested both in the dry state and after an accelerated conditioning in a climate chamber. Furthermore, finite element method (FEM) simulations were performed to model the extreme cases of optimum adhesion and no adhesion. By correlating the tensile tests with the simulation results and by analyzing the fracture surfaces, it was shown that the filler–matrix adhesion is sufficient in the dry state but is strongly degraded by conditioning. Even the presence of various organosilane thin films could not prevent a strong deterioration of the filler–matrix adhesion and the associated deterioration of the mechanical properties. Since a comparison with an injection-molded sample of the same polymer filler combination shows identical behavior after conditioning, it is assumed that this problem is not limited to additively manufactured parts.}}, author = {{Kletetzka, Ivo and Kosanke, Maren and Meinderink, Dennis and Neßlinger, Vanessa and Grundmeier, Guido and Schmid, Hans-Joachim}}, issn = {{2363-9512}}, journal = {{Progress in Additive Manufacturing}}, keywords = {{Industrial and Manufacturing Engineering}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Influence of the filler–matrix adhesion and the effects of conditioning on tensile properties of laser-sintered parts built with polyamide–glass bead dry blends}}}, doi = {{10.1007/s40964-023-00501-z}}, year = {{2023}}, } @article{43046, abstract = {{In the laser sintering technology, the semi-crystalline polymer material is exposed to elevated temperatures during processing, which leads to serious material ageing for most materials. This has already been investigated intensively by various authors. However, the ageing of the material at ambient temperatures during shelf life has not been the focus so far. The need to analyse the shelf life can be derived from an ecological and economic point of view. This work is focusing on the shelf life of PA2200 (PA12). To reduce the potential influences of powder production fluctuations, two different powder batches stored for 5.5 years and 6.5 years are investigated and compared to a reference powder produced 0.5 years before these investigations. Multiple powder analyses and part characterisations have been performed. A significant yellowing and molecular chain length reduction can be derived from the measurement results. Whereas the influence on mechanical part performance was minor, the parts built with the stored powders are more yellowish. As it is most likely that this is due to the consumption of polyamide stabilisers, it can be assumed that these parts will be subject to significantly faster ageing. Therefore, it is still not recommended to use the stored powders for critical parts or light intense and humid environments.}}, author = {{Klippstein, Sven Helge and Kletetzka, Ivo and Sural, Ilknur and Schmid, Hans-Joachim}}, journal = {{The International Journal of Advanced Manufacturing Technology }}, keywords = {{Selective laser sintering, Shelf life, Polyamide 12, powder, PA2200, material ageing}}, publisher = {{Springer}}, title = {{{Influence of a prolonged shelf time on PA12 laser sintering powder and resulting part properties}}}, doi = {{https://doi.org/10.1007/s00170-023-11243-1}}, year = {{2023}}, } @article{37466, abstract = {{Typically, head fakes in basketball are generated to, and actually do, deteriorate performance on the side of the observer. However, potential costs at the side of the producer of a fake action have only rarely been investigated before. It is thus not clear yet if the benefit (i.e., slowed reactions in the observer) of performing a head fake is overestimated due to concurrently arising fake production costs (i.e., slowed performance in the producer of a head fake). Therefore, we studied potential head-fake production costs with two experiments. Novice participants were asked to generate passes to the left or right side, either with or without head fakes. In Experiment 1, these actions were determined by an auditory stimulus (i.e., a 440 Hz or 1200 Hz sinus or jigsaw wave). After an interstimulus interval (ISI) of either 0 ms, 800 ms, or 1500 ms, which served the preparation of the action, the cued action had to be executed. In Experiment 2, passing to the left or right, either with or without a head fake, was determined by a visual stimulus (i.e., a player with a red or blue jersey defending either the right or left side). After an ISI of either 0 ms, 400 ms, 800 ms, or 1200 ms, the cued action had to be executed. In both experiments, we observed higher reaction times (RTs) for passes with head fakes as compared to passes without head fakes for no and an intermediate preparation interval (from ISI 0 ms to 800 ms), but no difference for a long preparation interval (for an ISI of 1200 ms and 1500 ms). Both experiments show that generating fake actions produces performance costs, however, these costs can be overcome by a longer preparation phase before movement execution.}}, author = {{Güldenpenning, Iris and Weigelt, Matthias and Böer, Nils Tobias and Kunde, Wilfried}}, issn = {{0167-9457}}, journal = {{Human Movement Science}}, keywords = {{Experimental and Cognitive Psychology, Orthopedics and Sports Medicine, General Medicine, Biophysics}}, publisher = {{Elsevier BV}}, title = {{{Producing deceptive actions in sports: The costs of generating head fakes in basketball}}}, doi = {{10.1016/j.humov.2022.103045}}, volume = {{87}}, year = {{2023}}, } @article{47065, abstract = {{The reform of the European academic landscape with the introduction of bachelor's and master's degree programs has brought about several profound changes for teaching and assessment in higher education. With regard to the examination system, the shift towards output-oriented teaching is still one of the most significant challenges. Assessments have to be integrated into the teaching and learning arrangements and consistently aligned towards the intended learning outcomes. In particular, assessments should provide valid evidence that learners have acquired competences that are relevant for a specific domain. However, it seems that this didactic goal has not yet been fully achieved in modeling education in computer science. The aim of this study is to investigate whether typical task material used in exercises and exams in modeling education at selected German universities covers relevant competences required for graphical modeling. For this purpose, typical tasks in the field of modeling are first identified by means of a content-analytical procedure. Subsequently, it is determined which competence facets relevant for graphical modeling are addressed by the task types. By contrasting a competence model for modeling with the competences addressed by the tasks, a gap was identified between the required competences and the task material analyzed. In particular, the gap analysis shows the neglect of transversal competence facets as well as those related to the analysis and evaluation of models. The result of this paper is a classification of task types for modeling education and a specification of the competence facets addressed by these tasks. Recommendations for developing and assessing student's competences comprehensively are given.}}, author = {{Soyka, Chantal and Ullrich, Meike and Striewe, Michael and Schaper, Niclas}}, journal = {{Enterprise Modelling and Information Systems Architectures}}, keywords = {{conceptual modeling, higher education, competence-oriented assessment, task analysis, graphical modeling}}, title = {{{Comparison of Required Competences and Task Material in Modeling Education}}}, doi = {{10.18417/EMISA.18.7}}, volume = {{18}}, year = {{2023}}, } @inproceedings{46957, abstract = {{Modern companies often face various challenges in concept development of products or systems. Design engineers prepare initial concepts as 3D models. These are then simulated by computational engineers. If requirements are not met, this necessitates an iterative process that runs between the design and computation departments until a valid concept is created. Design methods such as topology optimization are often used here. The upcoming result is then attempted to be adapted to certain manufacturing processes. These iteration loops can sometimes take a very long time, since the model construction and structural optimization generate large computational efforts. The present work shows on an example a methodical approach, which represents a first proof of concept, to solving this problem, including a description of methods and techniques, as well as possible problems in a detailed analysis concerning training data for neural networks and their abstraction capabilities. It is evident that additional research work needs to be conducted for further utilization in order to address all arising questions.}}, author = {{Ott, Manuel and Meihöfener, Niclas and Mozgova, Iryna}}, booktitle = {{Proceedings of the 34rd Annual International Solid Freeform Fabrication Symposium 2023}}, editor = {{Ott, Manuel}}, location = {{Austin, Texas, United States}}, title = {{{Methodical Approach to Reducing Design Time by using Neural Networks in Early Stages of Concept Development}}}, year = {{2023}}, } @article{47122, abstract = {{AbstractFeCo alloys are important materials used in pumps and motors in the offshore oil and gas drilling industry. These alloys are subjected to marine environments with a high NaCl concentration, therefore, corrosion and catastrophic failure are anticipated. So, the surface dissolution of additively manufactured FeCo samples is investigated in a quasi-in situ manner, in particular, the pitting corrosion in 5.0 wt pct NaCl solution. The local dissolution of the same sample region is monitored after 24, 72, and 168 hours. Here, the formation of rectangular and circular pits of ultra-fine dimensions (less than 0.5 µm) is observed with increasing immersion time. In addition, the formation of a corrosion-inhibiting surface layer is detected on the sample surface. Surface dissolution leads to a change in the surface structure, however, no change in grain shape or grain size is noticed. The surface topography after local dissolution is correlated to the grain orientation. Quasi-in situ analysis shows the preferential dissolution of high-angle grain boundaries (HAGBs) leading to a change in the fraction of HAGBs and low-angle grain boundaries fraction (LAGBs). For the FeCo sample, a potentiodynamic polarisation test reveals a corrosion potential (Ecorr) of − 0.475 V referred to the standard hydrogen electrode (SHE) and a corrosion exchange current density (icorr) of 0.0848 A/m2. Furthermore, quasi-in situ experiments showed that grains oriented along certain crystallographic directions are corroding more compared to other grains leading to a significant decrease in the local surface height. Grains with a plane normal close to the $$\langle {1}00\rangle$$ ⟨ 100 ⟩ direction reveal lower surface dissolution and higher corrosion resistance, whereas planes normal close to the $$\langle {11}0\rangle$$ ⟨ 110 ⟩ direction and the $$\langle {111}\rangle$$ ⟨ 111 ⟩ direction exhibit a higher surface dissolution.}}, author = {{Pramanik, Sudipta and Krüger, Jan Tobias and Schaper, Mirko and Hoyer, Kay-Peter}}, issn = {{1073-5623}}, journal = {{Metallurgical and Materials Transactions A}}, keywords = {{Metals and Alloys, Mechanics of Materials, Condensed Matter Physics}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Quasi-In Situ Localized Corrosion of an Additively Manufactured FeCo Alloy in 5 Wt Pct NaCl Solution}}}, doi = {{10.1007/s11661-023-07186-7}}, year = {{2023}}, } @article{47117, abstract = {{Trotz der Annahme, dass Langzeitpraktika im Lehramts-studium hohe Belastungen für Studierende darstellen können, sind empirische Analysen zum Einfluss sozialer (z.B. die Betreuung eigener Kinder, Pflegeaufgaben) und organisationaler Bedingungsfaktoren (z.B. Erwerbstätigkeit, Fahrzeiten zur Praktikumsschule, Zusatzkosten) rar. Daher wurden in diesem Beitrag im Rahmen einer Sekundäranalyse evaluativer Daten Zusammenhänge zwischen dem Belastungserleben von N = 611 Lehramtsstudierenden im Praxissemester an der Universität Paderborn und verschiedenen Bedingungsfaktoren untersucht. Das Belastungserleben wurde vor und nach dem Praxissemester mit Hilfe des Maslach-Burnout-Inventars (MBI-SS) erfasst. Regressionsanalysen ergaben, dass soziale und organisationale Bedingungsfaktoren kaum Unterschiede im Belastungserleben aufklären. Als einzige bedeutende Faktoren mit kleinen Effekten erwiesen sich die Fahrzeit zur Praktikumsschule und die Höhe evtl. zusätzlicher Materialkosten. Auch durch Clusteranalysen ermittelte Gruppen von hochbelasteten Studierenden zeichnen sich nicht durch spezifische soziale oder organisationale Bedingungsfaktoren aus.}}, author = {{Vogelsang, Christoph and Brandhorst, André}}, journal = {{Herausforderung Lehrer* Innenbildung-Zeitschrift Zur Konzeption, Gestaltung Und Diskussion}}, keywords = {{Praxissemester, Belastung, Burnout, Lehramtsstudium, soziale Situation}}, number = {{1}}, title = {{{Schulpraktikum zwischen Kind und Nebenjob? Einfluss von sozialen und organisationalen Bedingungsfaktoren auf das Belastungserleben Lehramtsstudierender im Praxissemester}}}, doi = {{10.11576/HLZ-5818}}, volume = {{6}}, year = {{2023}}, } @inbook{47059, author = {{Weigelt, Matthias and Krause, Daniel and Güldenpenning, Iris}}, booktitle = {{Sport and Exercise Psychology}}, editor = {{Schüler, J. and Wegner, M. and Plessner, H. and Eklund, R. C. }}, isbn = {{9783031039201}}, pages = {{41--70}}, publisher = {{Springer}}, title = {{{Learning and Memory in Sports}}}, doi = {{10.1007/978-3-031-03921-8_3}}, year = {{2023}}, }