[{"file":[{"creator":"coffen","description":"The article introduces a method to learn dynamical systems that\nare governed by Euler–Lagrange equations from data. The method is based on\nGaussian process regression and identifies continuous or discrete Lagrangians\nand is, therefore, structure preserving by design. A rigorous proof of con-\nvergence as the distance between observation data points converges to zero\nand lower bounds for convergence rates are provided. Next to convergence\nguarantees, the method allows for quantification of model uncertainty, which\ncan provide a basis of adaptive sampling techniques. We provide efficient uncertainty quantification of any observable that is linear in the Lagrangian,\nincluding of Hamiltonian functions (energy) and symplectic structures, which\nis of interest in the context of system identification. The article overcomes\nmajor practical and theoretical difficulties related to the ill-posedness of the\nidentification task of (discrete) Lagrangians through a careful design of geometric regularisation strategies and through an exploit of a relation to convex\nminimisation problems in reproducing kernel Hilbert spaces.","date_created":"2025-05-02T13:20:31Z","relation":"main_file","date_updated":"2025-05-02T13:20:31Z","file_name":"L_Collocation_ODE_mcom-l-template.pdf","access_level":"open_access","file_size":1819189,"title":"Machine learning of continuous and discrete variational ODEs with convergence guarantee and uncertainty quantification ","file_id":"59759","content_type":"application/pdf"}],"date_created":"2024-04-30T16:04:40Z","type":"journal_article","department":[{"_id":"636"}],"publication":"Mathematics of Computation","related_material":{"link":[{"url":"https://github.com/Christian-Offen/Lagrangian_GP","relation":"software","description":"GitHub"}]},"abstract":[{"text":"The article introduces a method to learn dynamical systems that are governed by Euler–Lagrange equations from data. The method is based on Gaussian process regression and identifies continuous or discrete Lagrangians and is, therefore, structure preserving by design. A rigorous proof of convergence as the distance between observation data points converges to zero and lower bounds for convergence rates are provided. Next to convergence guarantees, the method allows for quantification of model uncertainty, which can provide a basis of adaptive sampling techniques. We provide efficient uncertainty quantification of any observable that is linear in the Lagrangian, including of Hamiltonian functions (energy) and symplectic structures, which is of interest in the context of system identification. The article overcomes major practical and theoretical difficulties related to the ill-posedness of the identification task of (discrete) Lagrangians through a careful design of geometric regularisation strategies and through an exploit of a relation to convex minimisation problems in reproducing kernel Hilbert spaces.","lang":"eng"}],"language":[{"iso":"eng"}],"doi":"10.1090/mcom/4120","year":"2025","title":"Machine learning of continuous and discrete variational ODEs with convergence guarantee and uncertainty quantification","author":[{"full_name":"Offen, Christian","orcid":"0000-0002-5940-8057","last_name":"Offen","first_name":"Christian","id":"85279"}],"date_updated":"2025-06-29T13:03:55Z","publication_status":"epub_ahead","article_type":"original","external_id":{"arxiv":["arXiv:2404.19626"]},"oa":"1","file_date_updated":"2025-05-02T13:20:31Z","citation":{"ieee":"C. Offen, “Machine learning of continuous and discrete variational ODEs with convergence guarantee and uncertainty quantification,” Mathematics of Computation, 2025, doi: 10.1090/mcom/4120.","apa":"Offen, C. (2025). Machine learning of continuous and discrete variational ODEs with convergence guarantee and uncertainty quantification. Mathematics of Computation. https://doi.org/10.1090/mcom/4120","short":"C. Offen, Mathematics of Computation (2025).","chicago":"Offen, Christian. “Machine Learning of Continuous and Discrete Variational ODEs with Convergence Guarantee and Uncertainty Quantification.” Mathematics of Computation, 2025. https://doi.org/10.1090/mcom/4120.","mla":"Offen, Christian. “Machine Learning of Continuous and Discrete Variational ODEs with Convergence Guarantee and Uncertainty Quantification.” Mathematics of Computation, American Mathematical Society, 2025, doi:10.1090/mcom/4120.","bibtex":"@article{Offen_2025, title={Machine learning of continuous and discrete variational ODEs with convergence guarantee and uncertainty quantification}, DOI={10.1090/mcom/4120}, journal={Mathematics of Computation}, publisher={American Mathematical Society}, author={Offen, Christian}, year={2025} }","ama":"Offen C. Machine learning of continuous and discrete variational ODEs with convergence guarantee and uncertainty quantification. Mathematics of Computation. Published online 2025. doi:10.1090/mcom/4120"},"quality_controlled":"1","project":[{"name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"}],"publisher":"American Mathematical Society","_id":"53805","ddc":["510"],"user_id":"85279","status":"public","has_accepted_license":"1"},{"department":[{"_id":"27"}],"type":"journal_article","date_created":"2025-06-23T07:38:52Z","abstract":[{"lang":"eng","text":"In this work, we introduce PHOENIX, a highly optimized explicit open-source solver for two-dimensional nonlinear Schrödinger equations with extensions. The nonlinear Schrödinger equation and its extensions (Gross-Pitaevskii equation) are widely studied to model and analyze complex phenomena in fields such as optics, condensed matter physics, fluid dynamics, and plasma physics. It serves as a powerful tool for understanding nonlinear wave dynamics, soliton formation, and the interplay between nonlinearity, dispersion, and diffraction. By extending the nonlinear Schrödinger equation, various physical effects such as non-Hermiticity, spin-orbit interaction, and quantum optical aspects can be incorporated. PHOENIX is designed to accommodate a wide range of applications by a straightforward extendability without the need for user knowledge of computing architectures or performance optimization. The high performance and power efficiency of PHOENIX are demonstrated on a wide range of entry-class to high-end consumer and high-performance computing GPUs and CPUs. Compared to a more conventional MATLAB implementation, a speedup of up to three orders of magnitude and energy savings of up to 99.8% are achieved. The performance is compared to a performance model showing that PHOENIX performs close to the relevant performance bounds in many situations. The possibilities of PHOENIX are demonstrated with a range of practical examples from the realm of nonlinear (quantum) photonics in planar microresonators with active media including exciton-polariton condensates. Examples range from solutions on very large grids, the use of local optimization algorithms, to Monte Carlo ensemble evolutions with quantum noise enabling the tomography of the system's quantum state."}],"publication":"Computer Physics Communications","doi":"10.1016/j.cpc.2025.109689","language":[{"iso":"eng"}],"article_number":"109689","article_type":"original","intvolume":" 315","publication_status":"published","date_updated":"2025-06-29T12:00:36Z","author":[{"full_name":"Wingenbach, Jan","first_name":"Jan","last_name":"Wingenbach","id":"69187"},{"full_name":"Bauch, David","first_name":"David","last_name":"Bauch","id":"44172"},{"full_name":"Ma, Xuekai","last_name":"Ma","first_name":"Xuekai","id":"59416"},{"id":"75963","last_name":"Schade","first_name":"Robert","orcid":"0000-0002-6268-5397","full_name":"Schade, Robert"},{"id":"16153","orcid":"0000-0001-5728-9982","first_name":"Christian","last_name":"Plessl","full_name":"Plessl, Christian"},{"full_name":"Schumacher, Stefan","orcid":"0000-0003-4042-4951","first_name":"Stefan","last_name":"Schumacher","id":"27271"}],"publication_identifier":{"issn":["0010-4655"]},"title":"PHOENIX – Paderborn highly optimized and energy efficient solver for two-dimensional nonlinear Schrödinger equations with integrated extensions","year":"2025","project":[{"name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"}],"citation":{"mla":"Wingenbach, Jan, et al. “PHOENIX – Paderborn Highly Optimized and Energy Efficient Solver for Two-Dimensional Nonlinear Schrödinger Equations with Integrated Extensions.” Computer Physics Communications, vol. 315, 109689, Elsevier BV, 2025, doi:10.1016/j.cpc.2025.109689.","bibtex":"@article{Wingenbach_Bauch_Ma_Schade_Plessl_Schumacher_2025, title={PHOENIX – Paderborn highly optimized and energy efficient solver for two-dimensional nonlinear Schrödinger equations with integrated extensions}, volume={315}, DOI={10.1016/j.cpc.2025.109689}, number={109689}, journal={Computer Physics Communications}, publisher={Elsevier BV}, author={Wingenbach, Jan and Bauch, David and Ma, Xuekai and Schade, Robert and Plessl, Christian and Schumacher, Stefan}, year={2025} }","ama":"Wingenbach J, Bauch D, Ma X, Schade R, Plessl C, Schumacher S. PHOENIX – Paderborn highly optimized and energy efficient solver for two-dimensional nonlinear Schrödinger equations with integrated extensions. Computer Physics Communications. 2025;315. doi:10.1016/j.cpc.2025.109689","ieee":"J. Wingenbach, D. Bauch, X. Ma, R. Schade, C. Plessl, and S. Schumacher, “PHOENIX – Paderborn highly optimized and energy efficient solver for two-dimensional nonlinear Schrödinger equations with integrated extensions,” Computer Physics Communications, vol. 315, Art. no. 109689, 2025, doi: 10.1016/j.cpc.2025.109689.","apa":"Wingenbach, J., Bauch, D., Ma, X., Schade, R., Plessl, C., & Schumacher, S. (2025). PHOENIX – Paderborn highly optimized and energy efficient solver for two-dimensional nonlinear Schrödinger equations with integrated extensions. Computer Physics Communications, 315, Article 109689. https://doi.org/10.1016/j.cpc.2025.109689","short":"J. Wingenbach, D. Bauch, X. Ma, R. Schade, C. Plessl, S. Schumacher, Computer Physics Communications 315 (2025).","chicago":"Wingenbach, Jan, David Bauch, Xuekai Ma, Robert Schade, Christian Plessl, and Stefan Schumacher. “PHOENIX – Paderborn Highly Optimized and Energy Efficient Solver for Two-Dimensional Nonlinear Schrödinger Equations with Integrated Extensions.” Computer Physics Communications 315 (2025). https://doi.org/10.1016/j.cpc.2025.109689."},"volume":315,"user_id":"75963","publisher":"Elsevier BV","_id":"60298","status":"public"},{"title":"Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Streamlined Secondary Structures: A Numerical Analysis","year":"2025","author":[{"id":"90390","full_name":"Afsahnoudeh, Reza","orcid":"https://orcid.org/0009-0001-3161-8036","last_name":"Afsahnoudeh","first_name":"Reza"},{"full_name":"Riese, Julia","first_name":"Julia","last_name":"Riese","orcid":"0000-0002-3053-0534","id":"101499"},{"full_name":"Kenig, Eugeny Y.","first_name":"Eugeny Y.","last_name":"Kenig"}],"publication_identifier":{"issn":["2818-4734"]},"date_updated":"2025-07-02T07:57:08Z","publication_status":"published","intvolume":" 4","language":[{"iso":"eng"}],"doi":"10.69997/sct.178665","publication":"Systems and Control Transactions","abstract":[{"text":"Pillow-plate heat exchangers (PPHEs) represent a viable alternative to conventional shell-and-tube and plate heat exchangers. The waviness of their channels intensifies fluid mixing in the boundary layers and facilitates heat transfer. Applying secondary surface structuring can further enhance the overall thermo-hydraulic performance of PPHEs, thus increasing their competitiveness against conventional heat exchangers. In this work, streamlined secondary structures applied on the PPHE surface were studied numerically to explore their potential in enhancing near-wall fluid mixing. Computational fluid dynamics (CFD) simulations of single-phase turbulent flow in the inner PPHE channel were performed and pressure drop, heat transfer coefficients, and overall thermo-hydraulic efficiency were determined. The simulation results clearly demonstrate a favourable influence of secondary structuring on the heat transfer performance of PPHEs.","lang":"eng"}],"date_created":"2025-07-02T07:56:12Z","type":"conference","department":[{"_id":"831"}],"status":"public","_id":"60494","publisher":"PSE Press","user_id":"101499","volume":4,"citation":{"ieee":"R. Afsahnoudeh, J. Riese, and E. Y. Kenig, “Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Streamlined Secondary Structures: A Numerical Analysis,” in Systems and Control Transactions, 2025, vol. 4, doi: 10.69997/sct.178665.","apa":"Afsahnoudeh, R., Riese, J., & Kenig, E. Y. (2025). Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Streamlined Secondary Structures: A Numerical Analysis. Systems and Control Transactions, 4. https://doi.org/10.69997/sct.178665","short":"R. Afsahnoudeh, J. Riese, E.Y. Kenig, in: Systems and Control Transactions, PSE Press, 2025.","chicago":"Afsahnoudeh, Reza, Julia Riese, and Eugeny Y. Kenig. “Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Streamlined Secondary Structures: A Numerical Analysis.” In Systems and Control Transactions, Vol. 4. PSE Press, 2025. https://doi.org/10.69997/sct.178665.","mla":"Afsahnoudeh, Reza, et al. “Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Streamlined Secondary Structures: A Numerical Analysis.” Systems and Control Transactions, vol. 4, PSE Press, 2025, doi:10.69997/sct.178665.","bibtex":"@inproceedings{Afsahnoudeh_Riese_Kenig_2025, title={Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Streamlined Secondary Structures: A Numerical Analysis}, volume={4}, DOI={10.69997/sct.178665}, booktitle={Systems and Control Transactions}, publisher={PSE Press}, author={Afsahnoudeh, Reza and Riese, Julia and Kenig, Eugeny Y.}, year={2025} }","ama":"Afsahnoudeh R, Riese J, Kenig EY. Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Streamlined Secondary Structures: A Numerical Analysis. In: Systems and Control Transactions. Vol 4. PSE Press; 2025. doi:10.69997/sct.178665"},"quality_controlled":"1","project":[{"name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"}]},{"project":[{"name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"},{"_id":"53","grant_number":"231447078","name":"TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen"},{"_id":"54","name":"TRR 142 - A: TRR 142 - Project Area A"},{"_id":"55","name":"TRR 142 - B: TRR 142 - Project Area B"},{"grant_number":"231447078","_id":"168","name":"TRR 142 - B07: TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften von Lithiumniobat (B07*)"},{"_id":"166","name":"TRR 142 - A11: TRR 142 - Subproject A11"}],"citation":{"bibtex":"@article{Bocchini_Gerstmann_Schmidt_2025, title={Microscopic origin of gray tracks in <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:msub><mml:mi>KTiOPO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>}, volume={111}, DOI={10.1103/physrevb.111.104103}, number={10104103}, journal={Physical Review B}, publisher={American Physical Society (APS)}, author={Bocchini, Adriana and Gerstmann, Uwe and Schmidt, Wolf Gero}, year={2025} }","ama":"Bocchini A, Gerstmann U, Schmidt WG. Microscopic origin of gray tracks in <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:msub><mml:mi>KTiOPO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>. Physical Review B. 2025;111(10). doi:10.1103/physrevb.111.104103","mla":"Bocchini, Adriana, et al. “Microscopic Origin of Gray Tracks in <mml:Math Xmlns:Mml=\"http://Www.W3.Org/1998/Math/MathML\"><mml:Msub><mml:Mi>KTiOPO</Mml:Mi><mml:Mn>4</Mml:Mn></Mml:Msub></Mml:Math>.” Physical Review B, vol. 111, no. 10, 104103, American Physical Society (APS), 2025, doi:10.1103/physrevb.111.104103.","short":"A. Bocchini, U. Gerstmann, W.G. Schmidt, Physical Review B 111 (2025).","chicago":"Bocchini, Adriana, Uwe Gerstmann, and Wolf Gero Schmidt. “Microscopic Origin of Gray Tracks in <mml:Math Xmlns:Mml=\"http://Www.W3.Org/1998/Math/MathML\"><mml:Msub><mml:Mi>KTiOPO</Mml:Mi><mml:Mn>4</Mml:Mn></Mml:Msub></Mml:Math>.” Physical Review B 111, no. 10 (2025). https://doi.org/10.1103/physrevb.111.104103.","ieee":"A. Bocchini, U. Gerstmann, and W. G. Schmidt, “Microscopic origin of gray tracks in <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:msub><mml:mi>KTiOPO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>,” Physical Review B, vol. 111, no. 10, Art. no. 104103, 2025, doi: 10.1103/physrevb.111.104103.","apa":"Bocchini, A., Gerstmann, U., & Schmidt, W. G. (2025). Microscopic origin of gray tracks in <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:msub><mml:mi>KTiOPO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>. Physical Review B, 111(10), Article 104103. https://doi.org/10.1103/physrevb.111.104103"},"user_id":"16199","volume":111,"_id":"60565","publisher":"American Physical Society (APS)","status":"public","type":"journal_article","department":[{"_id":"15"},{"_id":"295"},{"_id":"790"},{"_id":"230"},{"_id":"429"},{"_id":"35"},{"_id":"170"},{"_id":"27"}],"date_created":"2025-07-09T08:58:32Z","issue":"10","publication":"Physical Review B","doi":"10.1103/physrevb.111.104103","article_number":"104103","language":[{"iso":"eng"}],"publication_status":"published","date_updated":"2025-07-09T09:30:31Z","intvolume":" 111","year":"2025","title":"Microscopic origin of gray tracks in KTiOPO4","author":[{"id":"58349","full_name":"Bocchini, Adriana","last_name":"Bocchini","first_name":"Adriana","orcid":"0000-0002-2134-3075"},{"id":"171","first_name":"Uwe","last_name":"Gerstmann","orcid":"0000-0002-4476-223X","full_name":"Gerstmann, Uwe"},{"orcid":"0000-0002-2717-5076","first_name":"Wolf Gero","last_name":"Schmidt","full_name":"Schmidt, Wolf Gero","id":"468"}],"publication_identifier":{"issn":["2469-9950","2469-9969"]}},{"_id":"58642","publisher":"Royal Society of Chemistry (RSC)","page":"537-548","volume":10,"user_id":"16199","status":"public","citation":{"apa":"Devaraj, V., Ruiz Alvarado, I. A., Lee, J.-M., Oh, J.-W., Gerstmann, U., Schmidt, W. G., & Zentgraf, T. (2025). Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror. Nanoscale Horizons, 10, 537–548. https://doi.org/10.1039/d4nh00546e","mla":"Devaraj, Vasanthan, et al. “Self-Assembly of Isolated Plasmonic Dimers with Sub-5 Nm Gaps on a Metallic Mirror.” Nanoscale Horizons, vol. 10, Royal Society of Chemistry (RSC), 2025, pp. 537–48, doi:10.1039/d4nh00546e.","ieee":"V. Devaraj et al., “Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror,” Nanoscale Horizons, vol. 10, pp. 537–548, 2025, doi: 10.1039/d4nh00546e.","short":"V. Devaraj, I.A. Ruiz Alvarado, J.-M. Lee, J.-W. Oh, U. Gerstmann, W.G. Schmidt, T. Zentgraf, Nanoscale Horizons 10 (2025) 537–548.","ama":"Devaraj V, Ruiz Alvarado IA, Lee J-M, et al. Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror. Nanoscale Horizons. 2025;10:537-548. doi:10.1039/d4nh00546e","chicago":"Devaraj, Vasanthan, Isaac Azahel Ruiz Alvarado, Jong-Min Lee, Jin-Woo Oh, Uwe Gerstmann, Wolf Gero Schmidt, and Thomas Zentgraf. “Self-Assembly of Isolated Plasmonic Dimers with Sub-5 Nm Gaps on a Metallic Mirror.” Nanoscale Horizons 10 (2025): 537–48. https://doi.org/10.1039/d4nh00546e.","bibtex":"@article{Devaraj_Ruiz Alvarado_Lee_Oh_Gerstmann_Schmidt_Zentgraf_2025, title={Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror}, volume={10}, DOI={10.1039/d4nh00546e}, journal={Nanoscale Horizons}, publisher={Royal Society of Chemistry (RSC)}, author={Devaraj, Vasanthan and Ruiz Alvarado, Isaac Azahel and Lee, Jong-Min and Oh, Jin-Woo and Gerstmann, Uwe and Schmidt, Wolf Gero and Zentgraf, Thomas}, year={2025}, pages={537–548} }"},"project":[{"_id":"53","grant_number":"231447078","name":"TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen"},{"_id":"168","grant_number":"231447078","name":"TRR 142 - B07: TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften von Lithiumniobat (B07*)"},{"name":"TRR 142 - B: TRR 142 - Project Area B","_id":"55"},{"_id":"445","grant_number":"367360193","name":"Hochleistungsrechner Noctua in Paderborn"},{"name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"}],"quality_controlled":"1","language":[{"iso":"eng"}],"doi":"10.1039/d4nh00546e","publication_identifier":{"issn":["2055-6756","2055-6764"]},"author":[{"first_name":"Vasanthan","last_name":"Devaraj","full_name":"Devaraj, Vasanthan","id":"103814"},{"id":"79462","last_name":"Ruiz Alvarado","orcid":"0000-0002-4710-1170","first_name":"Isaac Azahel","full_name":"Ruiz Alvarado, Isaac Azahel"},{"full_name":"Lee, Jong-Min","first_name":"Jong-Min","last_name":"Lee"},{"full_name":"Oh, Jin-Woo","last_name":"Oh","first_name":"Jin-Woo"},{"last_name":"Gerstmann","first_name":"Uwe","orcid":"0000-0002-4476-223X","full_name":"Gerstmann, Uwe","id":"171"},{"id":"468","first_name":"Wolf Gero","last_name":"Schmidt","orcid":"0000-0002-2717-5076","full_name":"Schmidt, Wolf Gero"},{"id":"30525","orcid":"0000-0002-8662-1101","first_name":"Thomas","last_name":"Zentgraf","full_name":"Zentgraf, Thomas"}],"title":"Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror","year":"2025","article_type":"original","intvolume":" 10","publication_status":"published","date_updated":"2025-07-09T14:04:39Z","date_created":"2025-02-14T08:13:10Z","department":[{"_id":"15"},{"_id":"230"},{"_id":"289"},{"_id":"623"},{"_id":"35"},{"_id":"295"},{"_id":"170"},{"_id":"429"},{"_id":"27"}],"type":"journal_article","publication":"Nanoscale Horizons","abstract":[{"lang":"eng","text":"We present a cost-effective self-assembly method to fabricate low-density dimer NPs in an NPoM architecture, using the M13 phage as a spacer layer. This will enable the development of dynamic plasmonic devices and advanced sensing applications."}]},{"year":"2025","title":"Mg dopants in lithium niobate: Defect models and impact on domain inversion","publication_identifier":{"issn":["2475-9953"]},"author":[{"id":"58349","first_name":"Adriana","last_name":"Bocchini","orcid":"0000-0002-2134-3075","full_name":"Bocchini, Adriana"},{"id":"22501","full_name":"Rüsing, Michael","first_name":"Michael","orcid":"0000-0003-4682-4577","last_name":"Rüsing"},{"last_name":"Bollmers","first_name":"Laura","full_name":"Bollmers, Laura","id":"61375"},{"id":"44373","first_name":"Sebastian","last_name":"Lengeling","full_name":"Lengeling, Sebastian"},{"id":"49772","first_name":"Philipp","last_name":"Mues","orcid":"0000-0003-0643-7636","full_name":"Mues, Philipp"},{"first_name":"Laura","last_name":"Padberg","full_name":"Padberg, Laura","id":"40300"},{"orcid":"0000-0002-4476-223X","last_name":"Gerstmann","first_name":"Uwe","full_name":"Gerstmann, Uwe","id":"171"},{"last_name":"Silberhorn","first_name":"Christine","full_name":"Silberhorn, Christine","id":"26263"},{"last_name":"Eigner","first_name":"Christof","orcid":"https://orcid.org/0000-0002-5693-3083","full_name":"Eigner, Christof","id":"13244"},{"last_name":"Schmidt","first_name":"Wolf Gero","orcid":"0000-0002-2717-5076","full_name":"Schmidt, Wolf Gero","id":"468"}],"publication_status":"published","date_updated":"2026-03-17T17:50:06Z","intvolume":" 9","article_number":"074402","main_file_link":[{"url":"https://link.aps.org/doi/10.1103/5wz1-bjyr","open_access":"1"}],"language":[{"iso":"eng"}],"doi":"10.1103/5wz1-bjyr","publication":"Physical Review Materials","issue":"7","file":[{"creator":"adrianab","date_created":"2025-07-09T09:18:45Z","date_updated":"2025-07-10T06:43:34Z","relation":"main_file","file_size":4175120,"access_level":"open_access","file_name":"Mg_dopants_LN_PRM.pdf","content_type":"application/pdf","file_id":"60567"}],"date_created":"2025-07-09T09:13:24Z","type":"journal_article","department":[{"_id":"15"},{"_id":"623"},{"_id":"295"},{"_id":"790"},{"_id":"288"},{"_id":"230"},{"_id":"429"},{"_id":"35"},{"_id":"170"},{"_id":"169"},{"_id":"27"}],"status":"public","has_accepted_license":"1","_id":"60566","publisher":"American Physical Society (APS)","user_id":"22501","ddc":["530"],"volume":9,"file_date_updated":"2025-07-10T06:43:34Z","citation":{"mla":"Bocchini, Adriana, et al. “Mg Dopants in Lithium Niobate: Defect Models and Impact on Domain Inversion.” Physical Review Materials, vol. 9, no. 7, 074402, American Physical Society (APS), 2025, doi:10.1103/5wz1-bjyr.","apa":"Bocchini, A., Rüsing, M., Bollmers, L., Lengeling, S., Mues, P., Padberg, L., Gerstmann, U., Silberhorn, C., Eigner, C., & Schmidt, W. G. (2025). Mg dopants in lithium niobate: Defect models and impact on domain inversion. Physical Review Materials, 9(7), Article 074402. https://doi.org/10.1103/5wz1-bjyr","ieee":"A. Bocchini et al., “Mg dopants in lithium niobate: Defect models and impact on domain inversion,” Physical Review Materials, vol. 9, no. 7, Art. no. 074402, 2025, doi: 10.1103/5wz1-bjyr.","ama":"Bocchini A, Rüsing M, Bollmers L, et al. Mg dopants in lithium niobate: Defect models and impact on domain inversion. Physical Review Materials. 2025;9(7). doi:10.1103/5wz1-bjyr","short":"A. Bocchini, M. Rüsing, L. Bollmers, S. Lengeling, P. Mues, L. Padberg, U. Gerstmann, C. Silberhorn, C. Eigner, W.G. Schmidt, Physical Review Materials 9 (2025).","chicago":"Bocchini, Adriana, Michael Rüsing, Laura Bollmers, Sebastian Lengeling, Philipp Mues, Laura Padberg, Uwe Gerstmann, Christine Silberhorn, Christof Eigner, and Wolf Gero Schmidt. “Mg Dopants in Lithium Niobate: Defect Models and Impact on Domain Inversion.” Physical Review Materials 9, no. 7 (2025). https://doi.org/10.1103/5wz1-bjyr.","bibtex":"@article{Bocchini_Rüsing_Bollmers_Lengeling_Mues_Padberg_Gerstmann_Silberhorn_Eigner_Schmidt_2025, title={Mg dopants in lithium niobate: Defect models and impact on domain inversion}, volume={9}, DOI={10.1103/5wz1-bjyr}, number={7074402}, journal={Physical Review Materials}, publisher={American Physical Society (APS)}, author={Bocchini, Adriana and Rüsing, Michael and Bollmers, Laura and Lengeling, Sebastian and Mues, Philipp and Padberg, Laura and Gerstmann, Uwe and Silberhorn, Christine and Eigner, Christof and Schmidt, Wolf Gero}, year={2025} }"},"project":[{"name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"},{"name":"TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen","_id":"53"},{"name":"TRR 142 - B: TRR 142 - Project Area B","_id":"55"},{"name":"TRR 142 - A: TRR 142 - Project Area A","_id":"54"},{"name":"TRR 142 - B07: TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften von Lithiumniobat (B07*)","_id":"168"},{"name":"TRR 142 - A11: TRR 142 - Subproject A11","_id":"166"}],"oa":"1"},{"project":[{"name":"TRR 285 – B01: TRR 285 - Subproject B01","_id":"140"},{"name":"TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen Prozessketten","_id":"130"},{"_id":"52","name":"Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"citation":{"short":"D.R. Devulapally, C. Steinfelder, T. Tröster, A. Brosius, in: MATEC Web of Conferences, EDP Sciences, 2025.","chicago":"Devulapally, Deekshith Reddy, Christian Steinfelder, Thomas Tröster, and Alexander Brosius. “Impact of Non-Rotationally Symmetric Joint Orientation on Neighbouring Joints and Component Performance in Lap Shear Specimens.” In MATEC Web of Conferences, Vol. 408. EDP Sciences, 2025. https://doi.org/10.1051/matecconf/202540801035.","apa":"Devulapally, D. R., Steinfelder, C., Tröster, T., & Brosius, A. (2025). Impact of non-rotationally symmetric joint orientation on neighbouring joints and component performance in lap shear specimens. MATEC Web of Conferences, 408, Article 01035. https://doi.org/10.1051/matecconf/202540801035","ieee":"D. R. Devulapally, C. Steinfelder, T. Tröster, and A. Brosius, “Impact of non-rotationally symmetric joint orientation on neighbouring joints and component performance in lap shear specimens,” in MATEC Web of Conferences, Lisabon,Portugal, 2025, vol. 408, doi: 10.1051/matecconf/202540801035.","ama":"Devulapally DR, Steinfelder C, Tröster T, Brosius A. Impact of non-rotationally symmetric joint orientation on neighbouring joints and component performance in lap shear specimens. In: MATEC Web of Conferences. Vol 408. EDP Sciences; 2025. doi:10.1051/matecconf/202540801035","bibtex":"@inproceedings{Devulapally_Steinfelder_Tröster_Brosius_2025, title={Impact of non-rotationally symmetric joint orientation on neighbouring joints and component performance in lap shear specimens}, volume={408}, DOI={10.1051/matecconf/202540801035}, number={01035}, booktitle={MATEC Web of Conferences}, publisher={EDP Sciences}, author={Devulapally, Deekshith Reddy and Steinfelder, Christian and Tröster, Thomas and Brosius, Alexander}, year={2025} }","mla":"Devulapally, Deekshith Reddy, et al. “Impact of Non-Rotationally Symmetric Joint Orientation on Neighbouring Joints and Component Performance in Lap Shear Specimens.” MATEC Web of Conferences, vol. 408, 01035, EDP Sciences, 2025, doi:10.1051/matecconf/202540801035."},"status":"public","conference":{"name":"44th Conference of the International Deep Drawing Research Group","location":"Lisabon,Portugal"},"user_id":"76837","volume":408,"publisher":"EDP Sciences","_id":"59897","abstract":[{"lang":"eng","text":"This paper discusses the influence of joint orientation with non-rotationally symmetric geometry, on load distribution and structural behavior. The focus is on understanding how changes in the alignment of individual joints affect the distribution of load, neighboring joints, and the overall performance of the component. Lap shear specimens with multiple joints arranged in a line are analyzed to explore these effects. Simplified models are used to model the joints in finite element simulations, allowing for efficient yet accurate analysis of the load distribution and structural response under varying joint orientations. Variations in joint orientation result in measurable changes in the distribution of forces on adjacent joints, influencing their behavior and that of the overall assembly. Experimental validation confirms the numerical results, providing deeper insights into the interaction between individual joints and their surroundings. This work contributes to the development of systematic approaches for optimizing the design of components with non-rotationally symmetric joints. The study highlights the importance of considering directional properties of joints in designing structural components."}],"publication":"MATEC Web of Conferences","type":"conference","department":[{"_id":"9"},{"_id":"321"},{"_id":"149"}],"date_created":"2025-05-14T11:28:32Z","publication_status":"published","date_updated":"2026-03-19T10:42:18Z","intvolume":" 408","title":"Impact of non-rotationally symmetric joint orientation on neighbouring joints and component performance in lap shear specimens","year":"2025","author":[{"id":"76837","full_name":"Devulapally, Deekshith Reddy","last_name":"Devulapally","first_name":"Deekshith Reddy"},{"first_name":"Christian","last_name":"Steinfelder","full_name":"Steinfelder, Christian"},{"id":"553","last_name":"Tröster","first_name":"Thomas","full_name":"Tröster, Thomas"},{"full_name":"Brosius, Alexander","last_name":"Brosius","first_name":"Alexander"}],"publication_identifier":{"issn":["2261-236X"]},"doi":"10.1051/matecconf/202540801035","article_number":"01035","language":[{"iso":"eng"}]},{"date_updated":"2026-03-19T12:05:17Z","author":[{"full_name":"Tröster, Thomas","first_name":"Thomas","last_name":"Tröster","id":"553"},{"id":"338","full_name":"Marten, Thorsten","last_name":"Marten","orcid":"0009-0001-6433-7839","first_name":"Thorsten"},{"id":"71335","full_name":"Luig, Simon","last_name":"Luig","first_name":"Simon"}],"publication_identifier":{"isbn":["978-3-96780-214-6"]},"title":"Methodische Auswahl hochfester Mehrphasenstähle bezüglich ihrer lokalen und globalen Duktilität","status":"public","year":"2025","alternative_title":["Schlussbericht vom 30.09.2024 zu IGF Vorhaben Nr. 21928N (Berichtszeitraum: 01.11.2021 bis 30.04.2024) "],"volume":"P 1447","user_id":"71335","language":[{"iso":"ger"}],"_id":"65062","series_title":"Salomon, R. (Hrsg.): Forschung für die Praxis / Forschungsvereinigung Stahlanwendung e.V","publisher":"Forschungsvereinigung Stahlanwendung e.V. (FOSTA)","project":[{"name":"Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"}],"citation":{"chicago":"Tröster, Thomas, Thorsten Marten, and Simon Luig. Methodische Auswahl hochfester Mehrphasenstähle bezüglich ihrer lokalen und globalen Duktilität. Vol. P 1447. Salomon, R. (Hrsg.): Forschung für die Praxis / Forschungsvereinigung Stahlanwendung e.V. Düsseldorf: Forschungsvereinigung Stahlanwendung e.V. (FOSTA), 2025.","short":"T. Tröster, T. Marten, S. Luig, Methodische Auswahl hochfester Mehrphasenstähle bezüglich ihrer lokalen und globalen Duktilität, Forschungsvereinigung Stahlanwendung e.V. (FOSTA), Düsseldorf, 2025.","ieee":"T. Tröster, T. Marten, and S. Luig, Methodische Auswahl hochfester Mehrphasenstähle bezüglich ihrer lokalen und globalen Duktilität, vol. P 1447. Düsseldorf: Forschungsvereinigung Stahlanwendung e.V. (FOSTA), 2025.","apa":"Tröster, T., Marten, T., & Luig, S. (2025). Methodische Auswahl hochfester Mehrphasenstähle bezüglich ihrer lokalen und globalen Duktilität: Vol. P 1447. Forschungsvereinigung Stahlanwendung e.V. (FOSTA).","bibtex":"@book{Tröster_Marten_Luig_2025, place={Düsseldorf}, series={Salomon, R. (Hrsg.): Forschung für die Praxis / Forschungsvereinigung Stahlanwendung e.V}, title={Methodische Auswahl hochfester Mehrphasenstähle bezüglich ihrer lokalen und globalen Duktilität}, volume={P 1447}, publisher={Forschungsvereinigung Stahlanwendung e.V. (FOSTA)}, author={Tröster, Thomas and Marten, Thorsten and Luig, Simon}, year={2025}, collection={Salomon, R. (Hrsg.): Forschung für die Praxis / Forschungsvereinigung Stahlanwendung e.V} }","ama":"Tröster T, Marten T, Luig S. Methodische Auswahl hochfester Mehrphasenstähle bezüglich ihrer lokalen und globalen Duktilität. Vol P 1447. Forschungsvereinigung Stahlanwendung e.V. (FOSTA); 2025.","mla":"Tröster, Thomas, et al. Methodische Auswahl hochfester Mehrphasenstähle bezüglich ihrer lokalen und globalen Duktilität. Forschungsvereinigung Stahlanwendung e.V. (FOSTA), 2025."},"department":[{"_id":"9"},{"_id":"321"},{"_id":"149"}],"type":"book","place":"Düsseldorf","date_created":"2026-03-19T11:37:39Z"},{"language":[{"iso":"eng"}],"_id":"65102","publisher":"ACM","user_id":"3145","doi":"10.1145/3731599.3767570","year":"2025","status":"public","title":"Towards Efficient Load Balancing BFS on GPUs: One Code for AMD, Intel & Nvidia","author":[{"first_name":"Kaan","last_name":"Olgu","full_name":"Olgu, Kaan"},{"id":"3145","full_name":"Kenter, Tobias","first_name":"Tobias","last_name":"Kenter"},{"full_name":"Nunez-Yanez, Jose","last_name":"Nunez-Yanez","first_name":"Jose"},{"full_name":"McIntosh-Smith, Simon","first_name":"Simon","last_name":"McIntosh-Smith"},{"full_name":"Deakin, Tom","first_name":"Tom","last_name":"Deakin"}],"publication_status":"published","date_updated":"2026-03-24T09:06:33Z","date_created":"2026-03-24T09:05:22Z","type":"conference","department":[{"_id":"27"},{"_id":"518"}],"publication":"Proceedings of the SC '25 Workshops of the International Conference for High Performance Computing, Networking, Storage and Analysis","citation":{"short":"K. Olgu, T. Kenter, J. Nunez-Yanez, S. McIntosh-Smith, T. Deakin, in: Proceedings of the SC ’25 Workshops of the International Conference for High Performance Computing, Networking, Storage and Analysis, ACM, 2025.","chicago":"Olgu, Kaan, Tobias Kenter, Jose Nunez-Yanez, Simon McIntosh-Smith, and Tom Deakin. “Towards Efficient Load Balancing BFS on GPUs: One Code for AMD, Intel & Nvidia.” In Proceedings of the SC ’25 Workshops of the International Conference for High Performance Computing, Networking, Storage and Analysis. ACM, 2025. https://doi.org/10.1145/3731599.3767570.","apa":"Olgu, K., Kenter, T., Nunez-Yanez, J., McIntosh-Smith, S., & Deakin, T. (2025). Towards Efficient Load Balancing BFS on GPUs: One Code for AMD, Intel & Nvidia. Proceedings of the SC ’25 Workshops of the International Conference for High Performance Computing, Networking, Storage and Analysis. https://doi.org/10.1145/3731599.3767570","ieee":"K. Olgu, T. Kenter, J. Nunez-Yanez, S. McIntosh-Smith, and T. Deakin, “Towards Efficient Load Balancing BFS on GPUs: One Code for AMD, Intel & Nvidia,” 2025, doi: 10.1145/3731599.3767570.","ama":"Olgu K, Kenter T, Nunez-Yanez J, McIntosh-Smith S, Deakin T. Towards Efficient Load Balancing BFS on GPUs: One Code for AMD, Intel & Nvidia. In: Proceedings of the SC ’25 Workshops of the International Conference for High Performance Computing, Networking, Storage and Analysis. ACM; 2025. doi:10.1145/3731599.3767570","bibtex":"@inproceedings{Olgu_Kenter_Nunez-Yanez_McIntosh-Smith_Deakin_2025, title={Towards Efficient Load Balancing BFS on GPUs: One Code for AMD, Intel & Nvidia}, DOI={10.1145/3731599.3767570}, booktitle={Proceedings of the SC ’25 Workshops of the International Conference for High Performance Computing, Networking, Storage and Analysis}, publisher={ACM}, author={Olgu, Kaan and Kenter, Tobias and Nunez-Yanez, Jose and McIntosh-Smith, Simon and Deakin, Tom}, year={2025} }","mla":"Olgu, Kaan, et al. “Towards Efficient Load Balancing BFS on GPUs: One Code for AMD, Intel & Nvidia.” Proceedings of the SC ’25 Workshops of the International Conference for High Performance Computing, Networking, Storage and Analysis, ACM, 2025, doi:10.1145/3731599.3767570."},"abstract":[{"lang":"eng","text":"Efficient graph processing is essential for a wide range of applications. Scalability and memory access patterns are still a challenge, especially with the Breadth-First Search algorithm. This work focuses on leveraging HPC systems with multiple GPUs available in a single node with peer-to-peer functionality of the Intel oneAPI implementation of SYCL. We propose three GPU-based load-balancing methods: work-group localisation for efficient data access, even workload distribution for higher GPU occupancy, and a hybrid strided-access approach for heuristic balancing. These methods ensure performance, portability, and productivity with a unified codebase. Our proposed methodologies outperform state-of-the-art single-GPU implementations based on CUDA on synthetic RMAT graphs. We analysed BFS performance across NVIDIA A100, Intel Max 1550, and AMD MI300X GPUs, achieving a peak performance of 153.27 GTEPS on an RMAT25-64 graph using 8 GPUs on the NVIDIA A100. Furthermore, our work demonstrates the capability to handle RMAT graphs up to scale 29, achieving superior performance on synthetic graphs and competitive results on real-world datasets."}],"project":[{"name":"Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"}]},{"publication":"Physical Review Research","issue":"1","date_created":"2024-01-24T15:17:37Z","type":"journal_article","department":[{"_id":"230"},{"_id":"623"},{"_id":"15"},{"_id":"170"},{"_id":"297"}],"year":"2024","title":"Swing-up dynamics in quantum emitter cavity systems: Near ideal single photons and entangled photon pairs","author":[{"id":"90283","full_name":"Heinisch, Nils","first_name":"Nils","last_name":"Heinisch"},{"last_name":"Köcher","first_name":"Nikolas","full_name":"Köcher, Nikolas","id":"79191"},{"id":"44172","last_name":"Bauch","first_name":"David","full_name":"Bauch, David"},{"id":"27271","full_name":"Schumacher, Stefan","orcid":"0000-0003-4042-4951","first_name":"Stefan","last_name":"Schumacher"}],"publication_identifier":{"issn":["2643-1564"]},"publication_status":"published","date_updated":"2024-01-24T16:07:57Z","intvolume":" 6","article_number":"L012017","language":[{"iso":"eng"}],"doi":"10.1103/PhysRevResearch.6.L012017","citation":{"chicago":"Heinisch, Nils, Nikolas Köcher, David Bauch, and Stefan Schumacher. “Swing-up Dynamics in Quantum Emitter Cavity Systems: Near Ideal Single Photons and Entangled Photon Pairs.” Physical Review Research 6, no. 1 (2024). https://doi.org/10.1103/PhysRevResearch.6.L012017.","short":"N. Heinisch, N. Köcher, D. Bauch, S. Schumacher, Physical Review Research 6 (2024).","ieee":"N. Heinisch, N. Köcher, D. Bauch, and S. Schumacher, “Swing-up dynamics in quantum emitter cavity systems: Near ideal single photons and entangled photon pairs,” Physical Review Research, vol. 6, no. 1, Art. no. L012017, 2024, doi: 10.1103/PhysRevResearch.6.L012017.","apa":"Heinisch, N., Köcher, N., Bauch, D., & Schumacher, S. (2024). Swing-up dynamics in quantum emitter cavity systems: Near ideal single photons and entangled photon pairs. Physical Review Research, 6(1), Article L012017. https://doi.org/10.1103/PhysRevResearch.6.L012017","bibtex":"@article{Heinisch_Köcher_Bauch_Schumacher_2024, title={Swing-up dynamics in quantum emitter cavity systems: Near ideal single photons and entangled photon pairs}, volume={6}, DOI={10.1103/PhysRevResearch.6.L012017}, number={1L012017}, journal={Physical Review Research}, publisher={American Physical Society (APS)}, author={Heinisch, Nils and Köcher, Nikolas and Bauch, David and Schumacher, Stefan}, year={2024} }","ama":"Heinisch N, Köcher N, Bauch D, Schumacher S. Swing-up dynamics in quantum emitter cavity systems: Near ideal single photons and entangled photon pairs. Physical Review Research. 2024;6(1). doi:10.1103/PhysRevResearch.6.L012017","mla":"Heinisch, Nils, et al. “Swing-up Dynamics in Quantum Emitter Cavity Systems: Near Ideal Single Photons and Entangled Photon Pairs.” Physical Review Research, vol. 6, no. 1, L012017, American Physical Society (APS), 2024, doi:10.1103/PhysRevResearch.6.L012017."},"project":[{"name":"TRR 142 - C09: TRR 142 - Ideale Erzeugung von Photonenpaaren für Verschränkungsaustausch bei Telekom Wellenlängen (C09*)","_id":"173","grant_number":"231447078"},{"name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"}],"status":"public","_id":"50829","publisher":"American Physical Society (APS)","user_id":"90283","volume":6},{"conference":{"name":"Jahrestreffen der Fachgruppe Fluidverfahrenstechnik","start_date":"2024-03-04","location":"Bochum","end_date":"2024-03-06"},"author":[{"id":"69828","last_name":"Dechert","first_name":"Christopher","full_name":"Dechert, Christopher"},{"id":"665","full_name":"Kenig, Eugeny","first_name":"Eugeny","last_name":"Kenig"}],"year":"2024","title":"Der Einfluss von Mikrostrukturen auf die Flüssigkeitsausbreitung in strukturierten Packungen","status":"public","date_updated":"2024-03-14T09:37:04Z","_id":"52573","language":[{"iso":"eng"}],"user_id":"69828","citation":{"apa":"Dechert, C., & Kenig, E. (2024). Der Einfluss von Mikrostrukturen auf die Flüssigkeitsausbreitung in strukturierten Packungen. Jahrestreffen der Fachgruppe Fluidverfahrenstechnik, Bochum.","ieee":"C. Dechert and E. Kenig, “Der Einfluss von Mikrostrukturen auf die Flüssigkeitsausbreitung in strukturierten Packungen,” presented at the Jahrestreffen der Fachgruppe Fluidverfahrenstechnik, Bochum, 2024.","chicago":"Dechert, Christopher, and Eugeny Kenig. “Der Einfluss von Mikrostrukturen Auf Die Flüssigkeitsausbreitung in Strukturierten Packungen,” 2024.","short":"C. Dechert, E. Kenig, in: 2024.","mla":"Dechert, Christopher, and Eugeny Kenig. Der Einfluss von Mikrostrukturen Auf Die Flüssigkeitsausbreitung in Strukturierten Packungen. 2024.","ama":"Dechert C, Kenig E. Der Einfluss von Mikrostrukturen auf die Flüssigkeitsausbreitung in strukturierten Packungen. In: ; 2024.","bibtex":"@inproceedings{Dechert_Kenig_2024, title={Der Einfluss von Mikrostrukturen auf die Flüssigkeitsausbreitung in strukturierten Packungen}, author={Dechert, Christopher and Kenig, Eugeny}, year={2024} }"},"project":[{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"date_created":"2024-03-14T09:36:50Z","department":[{"_id":"9"},{"_id":"831"}],"type":"conference_abstract"},{"oa":"1","external_id":{"arxiv":["2209.09977"]},"project":[{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"citation":{"ieee":"S. E. Otto, S. Peitz, and C. W. Rowley, “Learning Bilinear Models of Actuated Koopman Generators from  Partially-Observed Trajectories,” SIAM Journal on Applied Dynamical Systems, vol. 23, no. 1, pp. 885–923, 2024, doi: 10.1137/22M1523601.","apa":"Otto, S. E., Peitz, S., & Rowley, C. W. (2024). Learning Bilinear Models of Actuated Koopman Generators from  Partially-Observed Trajectories. SIAM Journal on Applied Dynamical Systems, 23(1), 885–923. https://doi.org/10.1137/22M1523601","short":"S.E. Otto, S. Peitz, C.W. Rowley, SIAM Journal on Applied Dynamical Systems 23 (2024) 885–923.","chicago":"Otto, Samuel E., Sebastian Peitz, and Clarence W. Rowley. “Learning Bilinear Models of Actuated Koopman Generators from  Partially-Observed Trajectories.” SIAM Journal on Applied Dynamical Systems 23, no. 1 (2024): 885–923. https://doi.org/10.1137/22M1523601.","mla":"Otto, Samuel E., et al. “Learning Bilinear Models of Actuated Koopman Generators from  Partially-Observed Trajectories.” SIAM Journal on Applied Dynamical Systems, vol. 23, no. 1, SIAM, 2024, pp. 885–923, doi:10.1137/22M1523601.","bibtex":"@article{Otto_Peitz_Rowley_2024, title={Learning Bilinear Models of Actuated Koopman Generators from  Partially-Observed Trajectories}, volume={23}, DOI={10.1137/22M1523601}, number={1}, journal={SIAM Journal on Applied Dynamical Systems}, publisher={SIAM}, author={Otto, Samuel E. and Peitz, Sebastian and Rowley, Clarence W.}, year={2024}, pages={885–923} }","ama":"Otto SE, Peitz S, Rowley CW. Learning Bilinear Models of Actuated Koopman Generators from  Partially-Observed Trajectories. SIAM Journal on Applied Dynamical Systems. 2024;23(1):885-923. doi:10.1137/22M1523601"},"user_id":"47427","volume":23,"page":"885-923","publisher":"SIAM","_id":"33461","status":"public","type":"journal_article","department":[{"_id":"655"}],"date_created":"2022-09-22T07:21:40Z","abstract":[{"lang":"eng","text":"Data-driven models for nonlinear dynamical systems based on approximating the underlying Koopman operator or generator have proven to be successful tools for forecasting, feature learning, state estimation, and control. It has become well known that the Koopman generators for control-affine systems also have affine dependence on the input, leading to convenient finite-dimensional bilinear approximations of the dynamics. Yet there are still two main obstacles that limit the scope of current approaches for approximating the Koopman generators of systems with actuation. First, the performance of existing methods depends heavily on the choice of basis functions over which the Koopman generator is to be approximated; and there is currently no universal way to choose them for systems that are not measure preserving. Secondly, if we do not observe the full state, we may not gain access to a sufficiently rich collection of such functions to describe the dynamics. This is because the commonly used method of forming time-delayed observables fails when there is actuation. To remedy these issues, we write the dynamics of observables governed by the Koopman generator as a bilinear hidden Markov model, and determine the model parameters using the expectation-maximization (EM) algorithm. The E-step involves a standard Kalman filter and smoother, while the M-step resembles control-affine dynamic mode decomposition for the generator. We demonstrate the performance of this method on three examples, including recovery of a finite-dimensional Koopman-invariant subspace for an actuated system with a slow manifold; estimation of Koopman eigenfunctions for the unforced Duffing equation; and model-predictive control of a fluidic pinball system based only on noisy observations of lift and drag."}],"publication":"SIAM Journal on Applied Dynamical Systems","issue":"1","doi":"10.1137/22M1523601","main_file_link":[{"open_access":"1","url":"https://arxiv.org/pdf/2209.09977.pdf"}],"language":[{"iso":"eng"}],"publication_status":"published","date_updated":"2024-03-18T10:40:08Z","intvolume":" 23","year":"2024","title":"Learning Bilinear Models of Actuated Koopman Generators from Partially-Observed Trajectories","author":[{"first_name":"Samuel E.","last_name":"Otto","full_name":"Otto, Samuel E."},{"last_name":"Peitz","orcid":"0000-0002-3389-793X","first_name":"Sebastian","full_name":"Peitz, Sebastian","id":"47427"},{"first_name":"Clarence W.","last_name":"Rowley","full_name":"Rowley, Clarence W."}]},{"citation":{"chicago":"Lass, Michael, Tobias Kenter, Christian Plessl, and Martin Brehm. “Characterizing Microheterogeneity in Liquid Mixtures via Local Density Fluctuations.” Entropy 26, no. 4 (2024). https://doi.org/10.3390/e26040322.","short":"M. Lass, T. Kenter, C. Plessl, M. Brehm, Entropy 26 (2024).","apa":"Lass, M., Kenter, T., Plessl, C., & Brehm, M. (2024). Characterizing Microheterogeneity in Liquid Mixtures via Local Density Fluctuations. Entropy, 26(4), Article 322. https://doi.org/10.3390/e26040322","ieee":"M. Lass, T. Kenter, C. Plessl, and M. Brehm, “Characterizing Microheterogeneity in Liquid Mixtures via Local Density Fluctuations,” Entropy, vol. 26, no. 4, Art. no. 322, 2024, doi: 10.3390/e26040322.","ama":"Lass M, Kenter T, Plessl C, Brehm M. Characterizing Microheterogeneity in Liquid Mixtures via Local Density Fluctuations. Entropy. 2024;26(4). doi:10.3390/e26040322","bibtex":"@article{Lass_Kenter_Plessl_Brehm_2024, title={Characterizing Microheterogeneity in Liquid Mixtures via Local Density Fluctuations}, volume={26}, DOI={10.3390/e26040322}, number={4322}, journal={Entropy}, publisher={MDPI AG}, author={Lass, Michael and Kenter, Tobias and Plessl, Christian and Brehm, Martin}, year={2024} }","mla":"Lass, Michael, et al. “Characterizing Microheterogeneity in Liquid Mixtures via Local Density Fluctuations.” Entropy, vol. 26, no. 4, 322, MDPI AG, 2024, doi:10.3390/e26040322."},"project":[{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"status":"public","publisher":"MDPI AG","_id":"53474","volume":26,"user_id":"24135","publication":"Entropy","issue":"4","abstract":[{"text":"We present a novel approach to characterize and quantify microheterogeneity and microphase separation in computer simulations of complex liquid mixtures. Our post-processing method is based on local density fluctuations of the different constituents in sampling spheres of varying size. It can be easily applied to both molecular dynamics (MD) and Monte Carlo (MC) simulations, including periodic boundary conditions. Multidimensional correlation of the density distributions yields a clear picture of the domain formation due to the subtle balance of different interactions. We apply our approach to the example of force field molecular dynamics simulations of imidazolium-based ionic liquids with different side chain lengths at different temperatures, namely 1-ethyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, and 1-decyl-3-methylimidazolium chloride, which are known to form distinct liquid domains. We put the results into the context of existing microheterogeneity analyses and demonstrate the advantages and sensitivity of our novel method. Furthermore, we show how to estimate the configuration entropy from our analysis, and we investigate voids in the system. The analysis has been implemented into our program package TRAVIS and is thus available as free software.","lang":"eng"}],"date_created":"2024-04-12T18:31:39Z","department":[{"_id":"27"},{"_id":"518"},{"_id":"803"}],"type":"journal_article","publication_identifier":{"issn":["1099-4300"]},"author":[{"full_name":"Lass, Michael","first_name":"Michael","orcid":"0000-0002-5708-7632","last_name":"Lass","id":"24135"},{"full_name":"Kenter, Tobias","first_name":"Tobias","last_name":"Kenter","id":"3145"},{"orcid":"0000-0001-5728-9982","last_name":"Plessl","first_name":"Christian","full_name":"Plessl, Christian","id":"16153"},{"id":"100167","first_name":"Martin","last_name":"Brehm","full_name":"Brehm, Martin"}],"year":"2024","title":"Characterizing Microheterogeneity in Liquid Mixtures via Local Density Fluctuations","intvolume":" 26","date_updated":"2024-04-12T18:34:32Z","publication_status":"published","language":[{"iso":"eng"}],"article_number":"322","doi":"10.3390/e26040322"},{"article_type":"original","intvolume":" 9","publication_status":"published","date_updated":"2024-04-26T08:44:30Z","author":[{"last_name":"Bauer","first_name":"Carsten","full_name":"Bauer, Carsten","id":"90082"},{"full_name":"Kenter, Tobias","first_name":"Tobias","last_name":"Kenter","id":"3145"},{"id":"24135","last_name":"Lass","first_name":"Michael","orcid":"0000-0002-5708-7632","full_name":"Lass, Michael"},{"id":"90492","last_name":"Mazur","first_name":"Lukas","orcid":" 0000-0001-6304-7082","full_name":"Mazur, Lukas"},{"last_name":"Meyer","first_name":"Marius","full_name":"Meyer, Marius","id":"40778"},{"id":"15272","first_name":"Holger","last_name":"Nitsche","full_name":"Nitsche, Holger"},{"id":"8961","full_name":"Riebler, Heinrich","last_name":"Riebler","first_name":"Heinrich"},{"orcid":"0000-0002-6268-5397","last_name":"Schade","first_name":"Robert","full_name":"Schade, Robert","id":"75963"},{"first_name":"Michael","last_name":"Schwarz","full_name":"Schwarz, Michael","id":"5312"},{"id":"61189","first_name":"Nils","last_name":"Winnwa","full_name":"Winnwa, Nils"},{"id":"23522","full_name":"Wiens, Alex","last_name":"Wiens","first_name":"Alex","orcid":"0000-0003-1764-9773"},{"first_name":"Xin","last_name":"Wu","full_name":"Wu, Xin","id":"77439"},{"id":"16153","first_name":"Christian","last_name":"Plessl","orcid":"0000-0001-5728-9982","full_name":"Plessl, Christian"},{"full_name":"Simon, Jens","last_name":"Simon","first_name":"Jens","id":"15273"}],"year":"2024","title":"Noctua 2 Supercomputer","doi":"10.17815/jlsrf-8-187 ","language":[{"iso":"eng"}],"abstract":[{"lang":"eng","text":"Noctua 2 is a supercomputer operated at the Paderborn Center for Parallel Computing (PC2) at Paderborn University in Germany. Noctua 2 was inaugurated in 2022 and is an Atos BullSequana XH2000 system. It consists mainly of three node types: 1) CPU Compute nodes with AMD EPYC processors in different main memory configurations, 2) GPU nodes with NVIDIA A100 GPUs, and 3) FPGA nodes with Xilinx Alveo U280 and Intel Stratix 10 FPGA cards. While CPUs and GPUs are known off-the-shelf components in HPC systems, the operation of a large number of FPGA cards from different vendors and a dedicated FPGA-to-FPGA network are unique characteristics of Noctua 2. This paper describes in detail the overall setup of Noctua 2 and gives insights into the operation of the cluster from a hardware, software and facility perspective."}],"publication":"Journal of large-scale research facilities","department":[{"_id":"27"},{"_id":"518"}],"keyword":["Noctua 2","Supercomputer","FPGA","PC2","Paderborn Center for Parallel Computing"],"type":"journal_article","date_created":"2024-04-26T07:39:41Z","file":[{"creator":"deffel","date_created":"2024-04-26T07:30:20Z","date_updated":"2024-04-26T08:35:17Z","relation":"main_file","access_level":"open_access","file_size":3825480,"file_name":"Noctua2_Supercomputer.pdf","content_type":"application/pdf","file_id":"53664"}],"has_accepted_license":"1","status":"public","volume":9,"user_id":"8961","ddc":["004"],"_id":"53663","project":[{"name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"}],"citation":{"chicago":"Bauer, Carsten, Tobias Kenter, Michael Lass, Lukas Mazur, Marius Meyer, Holger Nitsche, Heinrich Riebler, et al. “Noctua 2 Supercomputer.” Journal of Large-Scale Research Facilities 9 (2024). https://doi.org/10.17815/jlsrf-8-187 .","short":"C. Bauer, T. Kenter, M. Lass, L. Mazur, M. Meyer, H. Nitsche, H. Riebler, R. Schade, M. Schwarz, N. Winnwa, A. Wiens, X. Wu, C. Plessl, J. Simon, Journal of Large-Scale Research Facilities 9 (2024).","apa":"Bauer, C., Kenter, T., Lass, M., Mazur, L., Meyer, M., Nitsche, H., Riebler, H., Schade, R., Schwarz, M., Winnwa, N., Wiens, A., Wu, X., Plessl, C., & Simon, J. (2024). Noctua 2 Supercomputer. Journal of Large-Scale Research Facilities, 9. https://doi.org/10.17815/jlsrf-8-187 ","ieee":"C. Bauer et al., “Noctua 2 Supercomputer,” Journal of large-scale research facilities, vol. 9, 2024, doi: 10.17815/jlsrf-8-187 .","ama":"Bauer C, Kenter T, Lass M, et al. Noctua 2 Supercomputer. Journal of large-scale research facilities. 2024;9. doi:10.17815/jlsrf-8-187 ","bibtex":"@article{Bauer_Kenter_Lass_Mazur_Meyer_Nitsche_Riebler_Schade_Schwarz_Winnwa_et al._2024, title={Noctua 2 Supercomputer}, volume={9}, DOI={10.17815/jlsrf-8-187 }, journal={Journal of large-scale research facilities}, author={Bauer, Carsten and Kenter, Tobias and Lass, Michael and Mazur, Lukas and Meyer, Marius and Nitsche, Holger and Riebler, Heinrich and Schade, Robert and Schwarz, Michael and Winnwa, Nils and et al.}, year={2024} }","mla":"Bauer, Carsten, et al. “Noctua 2 Supercomputer.” Journal of Large-Scale Research Facilities, vol. 9, 2024, doi:10.17815/jlsrf-8-187 ."},"file_date_updated":"2024-04-26T08:35:17Z","oa":"1"},{"publication":"The World Wide Web Conference (WWW)","date_created":"2024-03-01T16:32:39Z","department":[{"_id":"760"}],"type":"conference","author":[{"first_name":"Lukas","last_name":"Blübaum","full_name":"Blübaum, Lukas"},{"last_name":"Heindorf","orcid":"0000-0002-4525-6865","first_name":"Stefan","full_name":"Heindorf, Stefan","id":"11871"}],"year":"2024","title":"Causal Question Answering with Reinforcement Learning","date_updated":"2024-05-26T19:01:34Z","publication_status":"accepted","language":[{"iso":"eng"}],"main_file_link":[{"url":"https://arxiv.org/abs/2311.02760","open_access":"1"}],"doi":"10.1145/3589334.3645610","citation":{"mla":"Blübaum, Lukas, and Stefan Heindorf. “Causal Question Answering with Reinforcement Learning.” The World Wide Web Conference (WWW), ACM, pp. 2204–2215, doi:10.1145/3589334.3645610.","ama":"Blübaum L, Heindorf S. Causal Question Answering with Reinforcement Learning. In: The World Wide Web Conference (WWW). ACM; :2204–2215. doi:10.1145/3589334.3645610","bibtex":"@inproceedings{Blübaum_Heindorf, title={Causal Question Answering with Reinforcement Learning}, DOI={10.1145/3589334.3645610}, booktitle={The World Wide Web Conference (WWW)}, publisher={ACM}, author={Blübaum, Lukas and Heindorf, Stefan}, pages={2204–2215} }","apa":"Blübaum, L., & Heindorf, S. (n.d.). Causal Question Answering with Reinforcement Learning. The World Wide Web Conference (WWW), 2204–2215. https://doi.org/10.1145/3589334.3645610","ieee":"L. Blübaum and S. Heindorf, “Causal Question Answering with Reinforcement Learning,” in The World Wide Web Conference (WWW), Singapore, pp. 2204–2215, doi: 10.1145/3589334.3645610.","short":"L. Blübaum, S. Heindorf, in: The World Wide Web Conference (WWW), ACM, n.d., pp. 2204–2215.","chicago":"Blübaum, Lukas, and Stefan Heindorf. “Causal Question Answering with Reinforcement Learning.” In The World Wide Web Conference (WWW), 2204–2215. ACM, n.d. https://doi.org/10.1145/3589334.3645610."},"project":[{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"oa":"1","conference":{"location":"Singapore","start_date":"2024-05-13","name":"The Web Conference","end_date":"2024-05-17"},"status":"public","_id":"52231","publisher":"ACM","page":"2204–2215","user_id":"11871"},{"main_file_link":[{"open_access":"1"}],"language":[{"iso":"eng"}],"date_updated":"2024-06-26T08:02:07Z","year":"2024","title":"Effects of task difficulty on visual processing speed","author":[{"id":"38219","full_name":"Banh, Ngoc Chi","last_name":"Banh","first_name":"Ngoc Chi","orcid":"0000-0002-5946-4542"},{"id":"451","orcid":"0000-0003-2364-9489","first_name":"Ingrid","last_name":"Scharlau","full_name":"Scharlau, Ingrid"}],"type":"conference_abstract","department":[{"_id":"424"},{"_id":"660"}],"file":[{"file_id":"53070","success":1,"content_type":"application/pdf","file_name":"Banh & Scharlau (2024) - Effects of task difficulty on visual processing speed.pdf","access_level":"closed","file_size":1237859,"relation":"main_file","date_updated":"2024-03-27T11:42:20Z","date_created":"2024-03-27T11:42:20Z","creator":"ncbanh"}],"date_created":"2024-03-27T11:43:51Z","ddc":["150"],"user_id":"38219","_id":"53069","has_accepted_license":"1","status":"public","conference":{"end_date":"2024-03-20","location":"Regensburg","start_date":"2024-03-17","name":"Tagung experimentell arbeitender Psycholog:innen (TeaP)"},"oa":"1","quality_controlled":"1","project":[{"name":"TRR 318 - A05: TRR 318 - Echtzeitmessung der Aufmerksamkeit im Mensch-Roboter-Erklärdialog (Teilprojekt A05)","grant_number":"438445824","_id":"115"},{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"file_date_updated":"2024-03-27T11:42:20Z","citation":{"apa":"Banh, N. C., & Scharlau, I. (2024). Effects of task difficulty on visual processing speed. Tagung experimentell arbeitender Psycholog:innen (TeaP), Regensburg.","ieee":"N. C. Banh and I. Scharlau, “Effects of task difficulty on visual processing speed,” presented at the Tagung experimentell arbeitender Psycholog:innen (TeaP), Regensburg, 2024.","chicago":"Banh, Ngoc Chi, and Ingrid Scharlau. “Effects of Task Difficulty on Visual Processing Speed,” 2024.","short":"N.C. Banh, I. Scharlau, in: 2024.","mla":"Banh, Ngoc Chi, and Ingrid Scharlau. Effects of Task Difficulty on Visual Processing Speed. 2024.","ama":"Banh NC, Scharlau I. Effects of task difficulty on visual processing speed. In: ; 2024.","bibtex":"@inproceedings{Banh_Scharlau_2024, title={Effects of task difficulty on visual processing speed}, author={Banh, Ngoc Chi and Scharlau, Ingrid}, year={2024} }"}},{"status":"public","_id":"55267","publisher":"American Physical Society (APS)","volume":109,"user_id":"16199","citation":{"apa":"Schäfer, F., Trautmann, A., Ngo, C., Steiner, J. T., Fuchs, C., Volz, K., Dobener, F., Stein, M., Meier, T., & Chatterjee, S. (2024). Optical Stark effect in type-II semiconductor heterostructures. Physical Review B, 109(7), Article 075301. https://doi.org/10.1103/physrevb.109.075301","ieee":"F. Schäfer et al., “Optical Stark effect in type-II semiconductor heterostructures,” Physical Review B, vol. 109, no. 7, Art. no. 075301, 2024, doi: 10.1103/physrevb.109.075301.","chicago":"Schäfer, F., A. Trautmann, C. Ngo, J. T. Steiner, C. Fuchs, K. Volz, F. Dobener, M. Stein, Torsten Meier, and S. Chatterjee. “Optical Stark Effect in Type-II Semiconductor Heterostructures.” Physical Review B 109, no. 7 (2024). https://doi.org/10.1103/physrevb.109.075301.","short":"F. Schäfer, A. Trautmann, C. Ngo, J.T. Steiner, C. Fuchs, K. Volz, F. Dobener, M. Stein, T. Meier, S. Chatterjee, Physical Review B 109 (2024).","mla":"Schäfer, F., et al. “Optical Stark Effect in Type-II Semiconductor Heterostructures.” Physical Review B, vol. 109, no. 7, 075301, American Physical Society (APS), 2024, doi:10.1103/physrevb.109.075301.","ama":"Schäfer F, Trautmann A, Ngo C, et al. Optical Stark effect in type-II semiconductor heterostructures. Physical Review B. 2024;109(7). doi:10.1103/physrevb.109.075301","bibtex":"@article{Schäfer_Trautmann_Ngo_Steiner_Fuchs_Volz_Dobener_Stein_Meier_Chatterjee_2024, title={Optical Stark effect in type-II semiconductor heterostructures}, volume={109}, DOI={10.1103/physrevb.109.075301}, number={7075301}, journal={Physical Review B}, publisher={American Physical Society (APS)}, author={Schäfer, F. and Trautmann, A. and Ngo, C. and Steiner, J. T. and Fuchs, C. and Volz, K. and Dobener, F. and Stein, M. and Meier, Torsten and Chatterjee, S.}, year={2024} }"},"project":[{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"},{"name":"TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen","_id":"53","grant_number":"231447078"},{"name":"TRR 142 - A10: TRR 142 - Nichtlinearitäten von atomar dünnen Übergangsmetall-Dichalkogeniden in starken Feldern (A10)","grant_number":"231447078","_id":"165"}],"author":[{"full_name":"Schäfer, F.","last_name":"Schäfer","first_name":"F."},{"full_name":"Trautmann, A.","first_name":"A.","last_name":"Trautmann"},{"full_name":"Ngo, C.","first_name":"C.","last_name":"Ngo"},{"full_name":"Steiner, J. T.","first_name":"J. T.","last_name":"Steiner"},{"first_name":"C.","last_name":"Fuchs","full_name":"Fuchs, C."},{"full_name":"Volz, K.","first_name":"K.","last_name":"Volz"},{"first_name":"F.","last_name":"Dobener","full_name":"Dobener, F."},{"full_name":"Stein, M.","last_name":"Stein","first_name":"M."},{"full_name":"Meier, Torsten","first_name":"Torsten","last_name":"Meier","orcid":"0000-0001-8864-2072","id":"344"},{"full_name":"Chatterjee, S.","last_name":"Chatterjee","first_name":"S."}],"publication_identifier":{"issn":["2469-9950","2469-9969"]},"title":"Optical Stark effect in type-II semiconductor heterostructures","year":"2024","intvolume":" 109","date_updated":"2024-07-15T09:49:41Z","publication_status":"published","language":[{"iso":"eng"}],"article_number":"075301","doi":"10.1103/physrevb.109.075301","issue":"7","publication":"Physical Review B","date_created":"2024-07-15T09:47:27Z","department":[{"_id":"15"},{"_id":"170"},{"_id":"293"},{"_id":"35"},{"_id":"230"},{"_id":"429"},{"_id":"27"}],"type":"journal_article"},{"author":[{"first_name":"Viktor","last_name":"Myroshnychenko","full_name":"Myroshnychenko, Viktor","id":"46371"},{"first_name":"Pious Mathews","last_name":"Mulavarickal Jose","full_name":"Mulavarickal Jose, Pious Mathews"},{"id":"53444","full_name":"Farheen, Henna","first_name":"Henna","last_name":"Farheen","orcid":"0000-0001-7730-3489"},{"first_name":"Shafaq","last_name":"Ejaz","full_name":"Ejaz, Shafaq"},{"last_name":"Brosseau","first_name":"Christian","full_name":"Brosseau, Christian"},{"id":"158","full_name":"Förstner, Jens","orcid":"0000-0001-7059-9862","last_name":"Förstner","first_name":"Jens"}],"publication_identifier":{"issn":["0031-8949","1402-4896"]},"title":"From Swiss-cheese to discrete ferroelectric composites: assessing the ferroelectric butterfly shape in polarization loops","year":"2024","intvolume":" 99","date_updated":"2024-07-22T07:43:53Z","publication_status":"published","language":[{"iso":"eng"}],"doi":"10.1088/1402-4896/ad3172","issue":"4","publication":"Physica Scripta","abstract":[{"text":"We explore the polarization hysteretic behaviour and field-dependent permittivity of ferroelectric-dielectric 2D materials formed by random dispersions of low permittivity inclusions in a ferroelectric matrix, using finite element simulations. We show how the degree of impenetrability of dielectric inclusions plays a substantial role in controlling the coercive field, remnant and saturation polarizations of the homogenized materials. The results highlight the significance of the degree of impenetrability of inclusion in tuning the effective polarization properties of such ferroelectric composites: coercive field drops significantly as percolation threshold is attained and remnant polarization decreases faster than a linear decay.","lang":"eng"}],"date_created":"2024-03-21T10:34:48Z","file":[{"relation":"main_file","date_updated":"2024-03-21T10:39:32Z","file_name":"2024-03 Myroshnychenko - Physica Scripta - From Swiss-cheese to discrete ferroelectric.pdf","file_size":5386508,"access_level":"open_access","file_id":"52701","content_type":"application/pdf","creator":"fossie","date_created":"2024-03-21T10:39:32Z"}],"department":[{"_id":"61"},{"_id":"230"}],"keyword":["tet_topic_ferro"],"type":"journal_article","status":"public","has_accepted_license":"1","publisher":"IOP Publishing","_id":"52700","page":"045952","volume":99,"ddc":["530"],"user_id":"158","citation":{"mla":"Myroshnychenko, Viktor, et al. “From Swiss-Cheese to Discrete Ferroelectric Composites: Assessing the Ferroelectric Butterfly Shape in Polarization Loops.” Physica Scripta, vol. 99, no. 4, IOP Publishing, 2024, p. 045952, doi:10.1088/1402-4896/ad3172.","ama":"Myroshnychenko V, Mulavarickal Jose PM, Farheen H, Ejaz S, Brosseau C, Förstner J. From Swiss-cheese to discrete ferroelectric composites: assessing the ferroelectric butterfly shape in polarization loops. Physica Scripta. 2024;99(4):045952. doi:10.1088/1402-4896/ad3172","bibtex":"@article{Myroshnychenko_Mulavarickal Jose_Farheen_Ejaz_Brosseau_Förstner_2024, title={From Swiss-cheese to discrete ferroelectric composites: assessing the ferroelectric butterfly shape in polarization loops}, volume={99}, DOI={10.1088/1402-4896/ad3172}, number={4}, journal={Physica Scripta}, publisher={IOP Publishing}, author={Myroshnychenko, Viktor and Mulavarickal Jose, Pious Mathews and Farheen, Henna and Ejaz, Shafaq and Brosseau, Christian and Förstner, Jens}, year={2024}, pages={045952} }","apa":"Myroshnychenko, V., Mulavarickal Jose, P. M., Farheen, H., Ejaz, S., Brosseau, C., & Förstner, J. (2024). From Swiss-cheese to discrete ferroelectric composites: assessing the ferroelectric butterfly shape in polarization loops. Physica Scripta, 99(4), 045952. https://doi.org/10.1088/1402-4896/ad3172","ieee":"V. Myroshnychenko, P. M. Mulavarickal Jose, H. Farheen, S. Ejaz, C. Brosseau, and J. Förstner, “From Swiss-cheese to discrete ferroelectric composites: assessing the ferroelectric butterfly shape in polarization loops,” Physica Scripta, vol. 99, no. 4, p. 045952, 2024, doi: 10.1088/1402-4896/ad3172.","chicago":"Myroshnychenko, Viktor, Pious Mathews Mulavarickal Jose, Henna Farheen, Shafaq Ejaz, Christian Brosseau, and Jens Förstner. “From Swiss-Cheese to Discrete Ferroelectric Composites: Assessing the Ferroelectric Butterfly Shape in Polarization Loops.” Physica Scripta 99, no. 4 (2024): 045952. https://doi.org/10.1088/1402-4896/ad3172.","short":"V. Myroshnychenko, P.M. Mulavarickal Jose, H. Farheen, S. Ejaz, C. Brosseau, J. Förstner, Physica Scripta 99 (2024) 045952."},"file_date_updated":"2024-03-21T10:39:32Z","project":[{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"oa":"1"},{"date_created":"2023-08-10T08:24:48Z","file":[{"access_level":"open_access","file_size":13222105,"file_name":"Accepted manuscript with AIP banner CHA23-AR-01370.pdf","date_updated":"2024-01-09T10:48:38Z","relation":"main_file","content_type":"application/pdf","file_id":"50376","title":"Accepted Manuscript Chaos","creator":"coffen","date_created":"2024-01-09T10:48:38Z"},{"description":"We show how to learn discrete field theories from observational data of fields on a space-time lattice. For this, we train\na neural network model of a discrete Lagrangian density such that the discrete Euler–Lagrange equations are consistent\nwith the given training data. We, thus, obtain a structure-preserving machine learning architecture. Lagrangian\ndensities are not uniquely defined by the solutions of a field theory. We introduce a technique to derive regularisers for\nthe training process which optimise numerical regularity of the discrete field theory. Minimisation of the regularisers\nguarantees that close to the training data the discrete field theory behaves robust and efficient when used in numerical\nsimulations. Further, we show how to identify structurally simple solutions of the underlying continuous field theory\nsuch as travelling waves. This is possible even when travelling waves are not present in the training data. This is\ncompared to data-driven model order reduction based approaches, which struggle to identify suitable latent spaces\ncontaining structurally simple solutions when these are not present in the training data. Ideas are demonstrated on\nexamples based on the wave equation and the Schrödinger equation.","date_created":"2024-01-09T11:19:49Z","creator":"coffen","title":"Learning of discrete models of variational PDEs from data","file_id":"50390","content_type":"application/pdf","relation":"main_file","date_updated":"2024-01-09T11:19:49Z","file_name":"LDensityPDE_AIP.pdf","access_level":"open_access","file_size":12960884}],"department":[{"_id":"636"}],"type":"journal_article","publication":"Chaos","issue":"1","related_material":{"link":[{"description":"GitHub","url":"https://github.com/Christian-Offen/DLNN_pde","relation":"software"}]},"abstract":[{"text":"We show how to learn discrete field theories from observational data of fields on a space-time lattice. For this, we train a neural network model of a discrete Lagrangian density such that the discrete Euler--Lagrange equations are consistent with the given training data. We, thus, obtain a structure-preserving machine learning architecture. Lagrangian densities are not uniquely defined by the solutions of a field theory. We introduce a technique to derive regularisers for the training process which optimise numerical regularity of the discrete field theory. Minimisation of the regularisers guarantees that close to the training data the discrete field theory behaves robust and efficient when used in numerical simulations. Further, we show how to identify structurally simple solutions of the underlying continuous field theory such as travelling waves. This is possible even when travelling waves are not present in the training data. This is compared to data-driven model order reduction based approaches, which struggle to identify suitable latent spaces containing structurally simple solutions when these are not present in the training data. Ideas are demonstrated on examples based on the wave equation and the Schrödinger equation. ","lang":"eng"}],"language":[{"iso":"eng"}],"article_number":"013104","doi":"10.1063/5.0172287","author":[{"full_name":"Offen, Christian","orcid":"0000-0002-5940-8057","first_name":"Christian","last_name":"Offen","id":"85279"},{"id":"16494","last_name":"Ober-Blöbaum","first_name":"Sina","full_name":"Ober-Blöbaum, Sina"}],"publication_identifier":{"issn":["1054-1500"]},"title":"Learning of discrete models of variational PDEs from data","year":"2024","article_type":"original","intvolume":" 34","publication_status":"published","date_updated":"2024-08-12T13:45:43Z","external_id":{"arxiv":["2308.05082 "]},"oa":"1","citation":{"ieee":"C. Offen and S. Ober-Blöbaum, “Learning of discrete models of variational PDEs from data,” Chaos, vol. 34, no. 1, Art. no. 013104, 2024, doi: 10.1063/5.0172287.","apa":"Offen, C., & Ober-Blöbaum, S. (2024). Learning of discrete models of variational PDEs from data. Chaos, 34(1), Article 013104. https://doi.org/10.1063/5.0172287","chicago":"Offen, Christian, and Sina Ober-Blöbaum. “Learning of Discrete Models of Variational PDEs from Data.” Chaos 34, no. 1 (2024). https://doi.org/10.1063/5.0172287.","short":"C. Offen, S. Ober-Blöbaum, Chaos 34 (2024).","mla":"Offen, Christian, and Sina Ober-Blöbaum. “Learning of Discrete Models of Variational PDEs from Data.” Chaos, vol. 34, no. 1, 013104, AIP Publishing, 2024, doi:10.1063/5.0172287.","bibtex":"@article{Offen_Ober-Blöbaum_2024, title={Learning of discrete models of variational PDEs from data}, volume={34}, DOI={10.1063/5.0172287}, number={1013104}, journal={Chaos}, publisher={AIP Publishing}, author={Offen, Christian and Ober-Blöbaum, Sina}, year={2024} }","ama":"Offen C, Ober-Blöbaum S. Learning of discrete models of variational PDEs from data. Chaos. 2024;34(1). doi:10.1063/5.0172287"},"file_date_updated":"2024-01-09T11:19:49Z","project":[{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"quality_controlled":"1","_id":"46469","publisher":"AIP Publishing","volume":34,"user_id":"85279","ddc":["510"],"status":"public","has_accepted_license":"1"},{"status":"public","has_accepted_license":"1","page":"28","_id":"55159","ddc":["510"],"user_id":"85279","file_date_updated":"2024-07-10T13:39:32Z","citation":{"ama":"Offen C. Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification.","bibtex":"@article{Offen, title={Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification}, author={Offen, Christian} }","mla":"Offen, Christian. Machine Learning of Discrete Field Theories with Guaranteed Convergence and Uncertainty Quantification.","short":"C. Offen, (n.d.).","chicago":"Offen, Christian. “Machine Learning of Discrete Field Theories with Guaranteed Convergence and Uncertainty Quantification,” n.d.","apa":"Offen, C. (n.d.). Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification.","ieee":"C. Offen, “Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification.” ."},"project":[{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"external_id":{"arxiv":["2407.07642"]},"oa":"1","title":"Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification","year":"2024","author":[{"id":"85279","full_name":"Offen, Christian","orcid":"0000-0002-5940-8057","first_name":"Christian","last_name":"Offen"}],"date_updated":"2024-08-12T13:43:32Z","publication_status":"submitted","language":[{"iso":"eng"}],"abstract":[{"lang":"eng","text":"We introduce a method based on Gaussian process regression to identify discrete variational principles from observed solutions of a field theory. The method is based on the data-based identification of a discrete Lagrangian density. It is a geometric machine learning technique in the sense that the variational structure of the true field theory is reflected in the data-driven model by design. We provide a rigorous convergence statement of the method. The proof circumvents challenges posed by the ambiguity of discrete Lagrangian densities in the inverse problem of variational calculus.\r\nMoreover, our method can be used to quantify model uncertainty in the equations of motions and any linear observable of the discrete field theory. This is illustrated on the example of the discrete wave equation and Schrödinger equation.\r\nThe article constitutes an extension of our previous article arXiv:2404.19626 for the data-driven identification of (discrete) Lagrangians for variational dynamics from an ode setting to the setting of discrete pdes."}],"related_material":{"link":[{"description":"GitHub","url":"https://github.com/Christian-Offen/Lagrangian_GP_PDE","relation":"software"}]},"file":[{"title":"Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification","content_type":"application/pdf","file_id":"55160","date_updated":"2024-07-10T13:39:32Z","relation":"main_file","access_level":"open_access","file_size":4569314,"file_name":"L_Collocation.pdf","description":"We introduce a method based on Gaussian process regression to identify discrete\nvariational principles from observed solutions of a field theory. The method is based on the data-based identification of a discrete Lagrangian density. It is a geometric machine learning technique in the sense that the variational structure of the true field theory is reflected in the data-driven model by design.\nWe provide a rigorous convergence statement of the method.\nThe proof circumvents challenges posed by the ambiguity of discrete Lagrangian densities in the inverse problem of variational calculus.\nMoreover, our method can be used to quantify model uncertainty in the equations of motions and any linear observable of the discrete field theory.\nThis is illustrated on the example of the discrete wave equation and Schrödinger equation.\nThe article constitutes an extension of our previous article for the data-driven identification of (discrete) Lagrangians for variational dynamics from an ode setting to the setting of discrete pdes.","date_created":"2024-07-10T13:39:32Z","creator":"coffen"}],"date_created":"2024-07-10T13:43:50Z","type":"preprint","keyword":["System identification","inverse problem of variational calculus","Gaussian process","Lagrangian learning","physics informed machine learning","geometry aware learning"],"department":[{"_id":"636"}]}]