---
_id: '53805'
abstract:
- lang: eng
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.
article_type: original
author:
- first_name: Christian
full_name: Offen, Christian
id: '85279'
last_name: Offen
orcid: 0000-0002-5940-8057
citation:
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
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
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} }'
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.
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.'
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.
short: C. Offen, Mathematics of Computation (2025).
date_created: 2024-04-30T16:04:40Z
date_updated: 2025-06-29T13:03:55Z
ddc:
- '510'
department:
- _id: '636'
doi: 10.1090/mcom/4120
external_id:
arxiv:
- arXiv:2404.19626
file:
- access_level: open_access
content_type: application/pdf
creator: coffen
date_created: 2025-05-02T13:20:31Z
date_updated: 2025-05-02T13:20:31Z
description: |-
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 con-
vergence 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.
file_id: '59759'
file_name: L_Collocation_ODE_mcom-l-template.pdf
file_size: 1819189
relation: main_file
title: 'Machine learning of continuous and discrete variational ODEs with convergence
guarantee and uncertainty quantification '
file_date_updated: 2025-05-02T13:20:31Z
has_accepted_license: '1'
language:
- iso: eng
oa: '1'
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: Mathematics of Computation
publication_status: epub_ahead
publisher: American Mathematical Society
quality_controlled: '1'
related_material:
link:
- description: GitHub
relation: software
url: https://github.com/Christian-Offen/Lagrangian_GP
status: public
title: Machine learning of continuous and discrete variational ODEs with convergence
guarantee and uncertainty quantification
type: journal_article
user_id: '85279'
year: '2025'
...
---
_id: '60298'
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.
article_number: '109689'
article_type: original
author:
- first_name: Jan
full_name: Wingenbach, Jan
id: '69187'
last_name: Wingenbach
- first_name: David
full_name: Bauch, David
id: '44172'
last_name: Bauch
- first_name: Xuekai
full_name: Ma, Xuekai
id: '59416'
last_name: Ma
- first_name: Robert
full_name: Schade, Robert
id: '75963'
last_name: Schade
orcid: 0000-0002-6268-5397
- first_name: Christian
full_name: Plessl, Christian
id: '16153'
last_name: Plessl
orcid: 0000-0001-5728-9982
- first_name: Stefan
full_name: Schumacher, Stefan
id: '27271'
last_name: Schumacher
orcid: 0000-0003-4042-4951
citation:
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
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
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} }'
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.
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.'
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.
short: J. Wingenbach, D. Bauch, X. Ma, R. Schade, C. Plessl, S. Schumacher, Computer
Physics Communications 315 (2025).
date_created: 2025-06-23T07:38:52Z
date_updated: 2025-06-29T12:00:36Z
department:
- _id: '27'
doi: 10.1016/j.cpc.2025.109689
intvolume: ' 315'
language:
- iso: eng
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: Computer Physics Communications
publication_identifier:
issn:
- 0010-4655
publication_status: published
publisher: Elsevier BV
status: public
title: PHOENIX – Paderborn highly optimized and energy efficient solver for two-dimensional
nonlinear Schrödinger equations with integrated extensions
type: journal_article
user_id: '75963'
volume: 315
year: '2025'
...
---
_id: '60494'
abstract:
- lang: eng
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.
author:
- first_name: Reza
full_name: Afsahnoudeh, Reza
id: '90390'
last_name: Afsahnoudeh
orcid: https://orcid.org/0009-0001-3161-8036
- first_name: Julia
full_name: Riese, Julia
id: '101499'
last_name: Riese
orcid: 0000-0002-3053-0534
- first_name: Eugeny Y.
full_name: Kenig, Eugeny Y.
last_name: Kenig
citation:
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'
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'
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} }'
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.'
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.'
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.'
short: 'R. Afsahnoudeh, J. Riese, E.Y. Kenig, in: Systems and Control Transactions,
PSE Press, 2025.'
date_created: 2025-07-02T07:56:12Z
date_updated: 2025-07-02T07:57:08Z
department:
- _id: '831'
doi: 10.69997/sct.178665
intvolume: ' 4'
language:
- iso: eng
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: Systems and Control Transactions
publication_identifier:
issn:
- 2818-4734
publication_status: published
publisher: PSE Press
quality_controlled: '1'
status: public
title: 'Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Streamlined
Secondary Structures: A Numerical Analysis'
type: conference
user_id: '101499'
volume: 4
year: '2025'
...
---
_id: '60565'
article_number: '104103'
author:
- first_name: Adriana
full_name: Bocchini, Adriana
id: '58349'
last_name: Bocchini
orcid: 0000-0002-2134-3075
- first_name: Uwe
full_name: Gerstmann, Uwe
id: '171'
last_name: Gerstmann
orcid: 0000-0002-4476-223X
- first_name: Wolf Gero
full_name: Schmidt, Wolf Gero
id: '468'
last_name: Schmidt
orcid: 0000-0002-2717-5076
citation:
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
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
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} }'
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.'
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).
date_created: 2025-07-09T08:58:32Z
date_updated: 2025-07-09T09:30:31Z
department:
- _id: '15'
- _id: '295'
- _id: '790'
- _id: '230'
- _id: '429'
- _id: '35'
- _id: '170'
- _id: '27'
doi: 10.1103/physrevb.111.104103
intvolume: ' 111'
issue: '10'
language:
- iso: eng
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
- _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'
- _id: '168'
grant_number: '231447078'
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'
publication: Physical Review B
publication_identifier:
issn:
- 2469-9950
- 2469-9969
publication_status: published
publisher: American Physical Society (APS)
status: public
title: Microscopic origin of gray tracks in KTiOPO4
type: journal_article
user_id: '16199'
volume: 111
year: '2025'
...
---
_id: '58642'
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.
article_type: original
author:
- first_name: Vasanthan
full_name: Devaraj, Vasanthan
id: '103814'
last_name: Devaraj
- first_name: Isaac Azahel
full_name: Ruiz Alvarado, Isaac Azahel
id: '79462'
last_name: Ruiz Alvarado
orcid: 0000-0002-4710-1170
- first_name: Jong-Min
full_name: Lee, Jong-Min
last_name: Lee
- first_name: Jin-Woo
full_name: Oh, Jin-Woo
last_name: Oh
- first_name: Uwe
full_name: Gerstmann, Uwe
id: '171'
last_name: Gerstmann
orcid: 0000-0002-4476-223X
- first_name: Wolf Gero
full_name: Schmidt, Wolf Gero
id: '468'
last_name: Schmidt
orcid: 0000-0002-2717-5076
- first_name: Thomas
full_name: Zentgraf, Thomas
id: '30525'
last_name: Zentgraf
orcid: 0000-0002-8662-1101
citation:
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
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
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}
}'
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.'
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.'
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.
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.
date_created: 2025-02-14T08:13:10Z
date_updated: 2025-07-09T14:04:39Z
department:
- _id: '15'
- _id: '230'
- _id: '289'
- _id: '623'
- _id: '35'
- _id: '295'
- _id: '170'
- _id: '429'
- _id: '27'
doi: 10.1039/d4nh00546e
intvolume: ' 10'
language:
- iso: eng
page: 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*)'
- _id: '55'
name: 'TRR 142 - B: TRR 142 - Project Area B'
- _id: '445'
grant_number: '367360193'
name: Hochleistungsrechner Noctua in Paderborn
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: Nanoscale Horizons
publication_identifier:
issn:
- 2055-6756
- 2055-6764
publication_status: published
publisher: Royal Society of Chemistry (RSC)
quality_controlled: '1'
status: public
title: Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic
mirror
type: journal_article
user_id: '16199'
volume: 10
year: '2025'
...
---
_id: '60566'
article_number: '074402'
author:
- first_name: Adriana
full_name: Bocchini, Adriana
id: '58349'
last_name: Bocchini
orcid: 0000-0002-2134-3075
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: Laura
full_name: Bollmers, Laura
id: '61375'
last_name: Bollmers
- first_name: Sebastian
full_name: Lengeling, Sebastian
id: '44373'
last_name: Lengeling
- first_name: Philipp
full_name: Mues, Philipp
id: '49772'
last_name: Mues
orcid: 0000-0003-0643-7636
- first_name: Laura
full_name: Padberg, Laura
id: '40300'
last_name: Padberg
- first_name: Uwe
full_name: Gerstmann, Uwe
id: '171'
last_name: Gerstmann
orcid: 0000-0002-4476-223X
- first_name: Christine
full_name: Silberhorn, Christine
id: '26263'
last_name: Silberhorn
- first_name: Christof
full_name: Eigner, Christof
id: '13244'
last_name: Eigner
orcid: https://orcid.org/0000-0002-5693-3083
- first_name: Wolf Gero
full_name: Schmidt, Wolf Gero
id: '468'
last_name: Schmidt
orcid: 0000-0002-2717-5076
citation:
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'
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'
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}
}'
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.'
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.'
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.'
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).
date_created: 2025-07-09T09:13:24Z
date_updated: 2026-03-17T17:50:06Z
ddc:
- '530'
department:
- _id: '15'
- _id: '623'
- _id: '295'
- _id: '790'
- _id: '288'
- _id: '230'
- _id: '429'
- _id: '35'
- _id: '170'
- _id: '169'
- _id: '27'
doi: 10.1103/5wz1-bjyr
file:
- access_level: open_access
content_type: application/pdf
creator: adrianab
date_created: 2025-07-09T09:18:45Z
date_updated: 2025-07-10T06:43:34Z
file_id: '60567'
file_name: Mg_dopants_LN_PRM.pdf
file_size: 4175120
relation: main_file
file_date_updated: 2025-07-10T06:43:34Z
has_accepted_license: '1'
intvolume: ' 9'
issue: '7'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://link.aps.org/doi/10.1103/5wz1-bjyr
oa: '1'
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
- _id: '53'
name: 'TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden
Konzepten zu funktionellen Strukturen'
- _id: '55'
name: 'TRR 142 - B: TRR 142 - Project Area B'
- _id: '54'
name: 'TRR 142 - A: TRR 142 - Project Area A'
- _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'
publication: Physical Review Materials
publication_identifier:
issn:
- 2475-9953
publication_status: published
publisher: American Physical Society (APS)
status: public
title: 'Mg dopants in lithium niobate: Defect models and impact on domain inversion'
type: journal_article
user_id: '22501'
volume: 9
year: '2025'
...
---
_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.
article_number: '01035'
author:
- first_name: Deekshith Reddy
full_name: Devulapally, Deekshith Reddy
id: '76837'
last_name: Devulapally
- first_name: Christian
full_name: Steinfelder, Christian
last_name: Steinfelder
- first_name: Thomas
full_name: Tröster, Thomas
id: '553'
last_name: Tröster
- first_name: Alexander
full_name: Brosius, Alexander
last_name: Brosius
citation:
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'
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
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} }'
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.
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.'
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.
short: 'D.R. Devulapally, C. Steinfelder, T. Tröster, A. Brosius, in: MATEC Web
of Conferences, EDP Sciences, 2025.'
conference:
location: Lisabon,Portugal
name: 44th Conference of the International Deep Drawing Research Group
date_created: 2025-05-14T11:28:32Z
date_updated: 2026-03-19T10:42:18Z
department:
- _id: '9'
- _id: '321'
- _id: '149'
doi: 10.1051/matecconf/202540801035
intvolume: ' 408'
language:
- iso: eng
project:
- _id: '140'
name: 'TRR 285 – B01: TRR 285 - Subproject B01'
- _id: '130'
name: 'TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen
Prozessketten'
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
publication: MATEC Web of Conferences
publication_identifier:
issn:
- 2261-236X
publication_status: published
publisher: EDP Sciences
status: public
title: Impact of non-rotationally symmetric joint orientation on neighbouring joints
and component performance in lap shear specimens
type: conference
user_id: '76837'
volume: 408
year: '2025'
...
---
_id: '65062'
alternative_title:
- 'Schlussbericht vom 30.09.2024 zu IGF Vorhaben Nr. 21928N (Berichtszeitraum: 01.11.2021
bis 30.04.2024) '
author:
- first_name: Thomas
full_name: Tröster, Thomas
id: '553'
last_name: Tröster
- first_name: Thorsten
full_name: Marten, Thorsten
id: '338'
last_name: Marten
orcid: 0009-0001-6433-7839
- first_name: Simon
full_name: Luig, Simon
id: '71335'
last_name: Luig
citation:
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.
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} }'
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.'
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.'
mla: Tröster, Thomas, et al. Methodische Auswahl hochfester Mehrphasenstähle
bezüglich ihrer lokalen und globalen Duktilität. 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.
date_created: 2026-03-19T11:37:39Z
date_updated: 2026-03-19T12:05:17Z
department:
- _id: '9'
- _id: '321'
- _id: '149'
language:
- iso: ger
place: Düsseldorf
project:
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
publication_identifier:
isbn:
- 978-3-96780-214-6
publisher: Forschungsvereinigung Stahlanwendung e.V. (FOSTA)
series_title: 'Salomon, R. (Hrsg.): Forschung für die Praxis / Forschungsvereinigung
Stahlanwendung e.V'
status: public
title: Methodische Auswahl hochfester Mehrphasenstähle bezüglich ihrer lokalen und
globalen Duktilität
type: book
user_id: '71335'
volume: P 1447
year: '2025'
...
---
_id: '65102'
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.'
author:
- first_name: Kaan
full_name: Olgu, Kaan
last_name: Olgu
- first_name: Tobias
full_name: Kenter, Tobias
id: '3145'
last_name: Kenter
- first_name: Jose
full_name: Nunez-Yanez, Jose
last_name: Nunez-Yanez
- first_name: Simon
full_name: McIntosh-Smith, Simon
last_name: McIntosh-Smith
- first_name: Tom
full_name: Deakin, Tom
last_name: Deakin
citation:
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'
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'
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}
}'
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.'
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.'
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.'
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.'
date_created: 2026-03-24T09:05:22Z
date_updated: 2026-03-24T09:06:33Z
department:
- _id: '27'
- _id: '518'
doi: 10.1145/3731599.3767570
language:
- iso: eng
project:
- _id: '52'
name: Computing Resources Provided by the Paderborn Center for Parallel Computing
publication: Proceedings of the SC '25 Workshops of the International Conference for
High Performance Computing, Networking, Storage and Analysis
publication_status: published
publisher: ACM
status: public
title: 'Towards Efficient Load Balancing BFS on GPUs: One Code for AMD, Intel & Nvidia'
type: conference
user_id: '3145'
year: '2025'
...
---
_id: '50829'
article_number: L012017
author:
- first_name: Nils
full_name: Heinisch, Nils
id: '90283'
last_name: Heinisch
- first_name: Nikolas
full_name: Köcher, Nikolas
id: '79191'
last_name: Köcher
- first_name: David
full_name: Bauch, David
id: '44172'
last_name: Bauch
- first_name: Stefan
full_name: Schumacher, Stefan
id: '27271'
last_name: Schumacher
orcid: 0000-0003-4042-4951
citation:
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'
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} }'
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.'
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.'
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.'
short: N. Heinisch, N. Köcher, D. Bauch, S. Schumacher, Physical Review Research
6 (2024).
date_created: 2024-01-24T15:17:37Z
date_updated: 2024-01-24T16:07:57Z
department:
- _id: '230'
- _id: '623'
- _id: '15'
- _id: '170'
- _id: '297'
doi: 10.1103/PhysRevResearch.6.L012017
intvolume: ' 6'
issue: '1'
language:
- iso: eng
project:
- _id: '173'
grant_number: '231447078'
name: 'TRR 142 - C09: TRR 142 - Ideale Erzeugung von Photonenpaaren für Verschränkungsaustausch
bei Telekom Wellenlängen (C09*)'
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: Physical Review Research
publication_identifier:
issn:
- 2643-1564
publication_status: published
publisher: American Physical Society (APS)
status: public
title: 'Swing-up dynamics in quantum emitter cavity systems: Near ideal single photons
and entangled photon pairs'
type: journal_article
user_id: '90283'
volume: 6
year: '2024'
...
---
_id: '52573'
author:
- first_name: Christopher
full_name: Dechert, Christopher
id: '69828'
last_name: Dechert
- first_name: Eugeny
full_name: Kenig, Eugeny
id: '665'
last_name: Kenig
citation:
ama: 'Dechert C, Kenig E. Der Einfluss von Mikrostrukturen auf die Flüssigkeitsausbreitung
in strukturierten Packungen. In: ; 2024.'
apa: Dechert, C., & Kenig, E. (2024). Der Einfluss von Mikrostrukturen auf
die Flüssigkeitsausbreitung in strukturierten Packungen. Jahrestreffen der
Fachgruppe Fluidverfahrenstechnik, Bochum.
bibtex: '@inproceedings{Dechert_Kenig_2024, title={Der Einfluss von Mikrostrukturen
auf die Flüssigkeitsausbreitung in strukturierten Packungen}, author={Dechert,
Christopher and Kenig, Eugeny}, year={2024} }'
chicago: Dechert, Christopher, and Eugeny Kenig. “Der Einfluss von Mikrostrukturen
Auf Die Flüssigkeitsausbreitung in Strukturierten Packungen,” 2024.
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.
mla: Dechert, Christopher, and Eugeny Kenig. Der Einfluss von Mikrostrukturen
Auf Die Flüssigkeitsausbreitung in Strukturierten Packungen. 2024.
short: 'C. Dechert, E. Kenig, in: 2024.'
conference:
end_date: 2024-03-06
location: Bochum
name: Jahrestreffen der Fachgruppe Fluidverfahrenstechnik
start_date: 2024-03-04
date_created: 2024-03-14T09:36:50Z
date_updated: 2024-03-14T09:37:04Z
department:
- _id: '9'
- _id: '831'
language:
- iso: eng
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
status: public
title: Der Einfluss von Mikrostrukturen auf die Flüssigkeitsausbreitung in strukturierten
Packungen
type: conference_abstract
user_id: '69828'
year: '2024'
...
---
_id: '33461'
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.
author:
- first_name: Samuel E.
full_name: Otto, Samuel E.
last_name: Otto
- first_name: Sebastian
full_name: Peitz, Sebastian
id: '47427'
last_name: Peitz
orcid: 0000-0002-3389-793X
- first_name: Clarence W.
full_name: Rowley, Clarence W.
last_name: Rowley
citation:
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
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
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}
}'
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.'
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.'
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.
short: S.E. Otto, S. Peitz, C.W. Rowley, SIAM Journal on Applied Dynamical Systems
23 (2024) 885–923.
date_created: 2022-09-22T07:21:40Z
date_updated: 2024-03-18T10:40:08Z
department:
- _id: '655'
doi: 10.1137/22M1523601
external_id:
arxiv:
- '2209.09977'
intvolume: ' 23'
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/pdf/2209.09977.pdf
oa: '1'
page: 885-923
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: SIAM Journal on Applied Dynamical Systems
publication_status: published
publisher: SIAM
status: public
title: Learning Bilinear Models of Actuated Koopman Generators from Partially-Observed
Trajectories
type: journal_article
user_id: '47427'
volume: 23
year: '2024'
...
---
_id: '53474'
abstract:
- lang: eng
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.
article_number: '322'
author:
- first_name: Michael
full_name: Lass, Michael
id: '24135'
last_name: Lass
orcid: 0000-0002-5708-7632
- first_name: Tobias
full_name: Kenter, Tobias
id: '3145'
last_name: Kenter
- first_name: Christian
full_name: Plessl, Christian
id: '16153'
last_name: Plessl
orcid: 0000-0001-5728-9982
- first_name: Martin
full_name: Brehm, Martin
id: '100167'
last_name: Brehm
citation:
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
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
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} }'
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.
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.'
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.
short: M. Lass, T. Kenter, C. Plessl, M. Brehm, Entropy 26 (2024).
date_created: 2024-04-12T18:31:39Z
date_updated: 2024-04-12T18:34:32Z
department:
- _id: '27'
- _id: '518'
- _id: '803'
doi: 10.3390/e26040322
intvolume: ' 26'
issue: '4'
language:
- iso: eng
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: Entropy
publication_identifier:
issn:
- 1099-4300
publication_status: published
publisher: MDPI AG
status: public
title: Characterizing Microheterogeneity in Liquid Mixtures via Local Density Fluctuations
type: journal_article
user_id: '24135'
volume: 26
year: '2024'
...
---
_id: '53663'
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.'
article_type: original
author:
- first_name: Carsten
full_name: Bauer, Carsten
id: '90082'
last_name: Bauer
- first_name: Tobias
full_name: Kenter, Tobias
id: '3145'
last_name: Kenter
- first_name: Michael
full_name: Lass, Michael
id: '24135'
last_name: Lass
orcid: 0000-0002-5708-7632
- first_name: Lukas
full_name: Mazur, Lukas
id: '90492'
last_name: Mazur
orcid: ' 0000-0001-6304-7082'
- first_name: Marius
full_name: Meyer, Marius
id: '40778'
last_name: Meyer
- first_name: Holger
full_name: Nitsche, Holger
id: '15272'
last_name: Nitsche
- first_name: Heinrich
full_name: Riebler, Heinrich
id: '8961'
last_name: Riebler
- first_name: Robert
full_name: Schade, Robert
id: '75963'
last_name: Schade
orcid: 0000-0002-6268-5397
- first_name: Michael
full_name: Schwarz, Michael
id: '5312'
last_name: Schwarz
- first_name: Nils
full_name: Winnwa, Nils
id: '61189'
last_name: Winnwa
- first_name: Alex
full_name: Wiens, Alex
id: '23522'
last_name: Wiens
orcid: 0000-0003-1764-9773
- first_name: Xin
full_name: Wu, Xin
id: '77439'
last_name: Wu
- first_name: Christian
full_name: Plessl, Christian
id: '16153'
last_name: Plessl
orcid: 0000-0001-5728-9982
- first_name: Jens
full_name: Simon, Jens
id: '15273'
last_name: Simon
citation:
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
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
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} }'
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 .
ieee: 'C. Bauer et al., “Noctua 2 Supercomputer,” Journal of large-scale
research facilities, vol. 9, 2024, doi: 10.17815/jlsrf-8-187 .'
mla: Bauer, Carsten, et al. “Noctua 2 Supercomputer.” Journal of Large-Scale
Research Facilities, vol. 9, 2024, doi: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).
date_created: 2024-04-26T07:39:41Z
date_updated: 2024-04-26T08:44:30Z
ddc:
- '004'
department:
- _id: '27'
- _id: '518'
doi: '10.17815/jlsrf-8-187 '
file:
- access_level: open_access
content_type: application/pdf
creator: deffel
date_created: 2024-04-26T07:30:20Z
date_updated: 2024-04-26T08:35:17Z
file_id: '53664'
file_name: Noctua2_Supercomputer.pdf
file_size: 3825480
relation: main_file
file_date_updated: 2024-04-26T08:35:17Z
has_accepted_license: '1'
intvolume: ' 9'
keyword:
- Noctua 2
- Supercomputer
- FPGA
- PC2
- Paderborn Center for Parallel Computing
language:
- iso: eng
oa: '1'
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: Journal of large-scale research facilities
publication_status: published
status: public
title: Noctua 2 Supercomputer
type: journal_article
user_id: '8961'
volume: 9
year: '2024'
...
---
_id: '52231'
author:
- first_name: Lukas
full_name: Blübaum, Lukas
last_name: Blübaum
- first_name: Stefan
full_name: Heindorf, Stefan
id: '11871'
last_name: Heindorf
orcid: 0000-0002-4525-6865
citation:
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'
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
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} }'
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.
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.'
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.
short: 'L. Blübaum, S. Heindorf, in: The World Wide Web Conference (WWW), ACM, n.d.,
pp. 2204–2215.'
conference:
end_date: 2024-05-17
location: Singapore
name: The Web Conference
start_date: 2024-05-13
date_created: 2024-03-01T16:32:39Z
date_updated: 2024-05-26T19:01:34Z
department:
- _id: '760'
doi: 10.1145/3589334.3645610
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/2311.02760
oa: '1'
page: 2204–2215
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: The World Wide Web Conference (WWW)
publication_status: accepted
publisher: ACM
status: public
title: Causal Question Answering with Reinforcement Learning
type: conference
user_id: '11871'
year: '2024'
...
---
_id: '53069'
author:
- first_name: Ngoc Chi
full_name: Banh, Ngoc Chi
id: '38219'
last_name: Banh
orcid: 0000-0002-5946-4542
- first_name: Ingrid
full_name: Scharlau, Ingrid
id: '451'
last_name: Scharlau
orcid: 0000-0003-2364-9489
citation:
ama: 'Banh NC, Scharlau I. Effects of task difficulty on visual processing speed.
In: ; 2024.'
apa: Banh, N. C., & Scharlau, I. (2024). Effects of task difficulty on visual
processing speed. Tagung experimentell arbeitender Psycholog:innen (TeaP),
Regensburg.
bibtex: '@inproceedings{Banh_Scharlau_2024, title={Effects of task difficulty on
visual processing speed}, author={Banh, Ngoc Chi and Scharlau, Ingrid}, year={2024}
}'
chicago: Banh, Ngoc Chi, and Ingrid Scharlau. “Effects of Task Difficulty on Visual
Processing Speed,” 2024.
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.
mla: Banh, Ngoc Chi, and Ingrid Scharlau. Effects of Task Difficulty on Visual
Processing Speed. 2024.
short: 'N.C. Banh, I. Scharlau, in: 2024.'
conference:
end_date: 2024-03-20
location: Regensburg
name: Tagung experimentell arbeitender Psycholog:innen (TeaP)
start_date: 2024-03-17
date_created: 2024-03-27T11:43:51Z
date_updated: 2024-06-26T08:02:07Z
ddc:
- '150'
department:
- _id: '424'
- _id: '660'
file:
- access_level: closed
content_type: application/pdf
creator: ncbanh
date_created: 2024-03-27T11:42:20Z
date_updated: 2024-03-27T11:42:20Z
file_id: '53070'
file_name: Banh & Scharlau (2024) - Effects of task difficulty on visual processing
speed.pdf
file_size: 1237859
relation: main_file
success: 1
file_date_updated: 2024-03-27T11:42:20Z
has_accepted_license: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
oa: '1'
project:
- _id: '115'
grant_number: '438445824'
name: 'TRR 318 - A05: TRR 318 - Echtzeitmessung der Aufmerksamkeit im Mensch-Roboter-Erklärdialog
(Teilprojekt A05)'
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
quality_controlled: '1'
status: public
title: Effects of task difficulty on visual processing speed
type: conference_abstract
user_id: '38219'
year: '2024'
...
---
_id: '55267'
article_number: '075301'
author:
- first_name: F.
full_name: Schäfer, F.
last_name: Schäfer
- first_name: A.
full_name: Trautmann, A.
last_name: Trautmann
- first_name: C.
full_name: Ngo, C.
last_name: Ngo
- first_name: J. T.
full_name: Steiner, J. T.
last_name: Steiner
- first_name: C.
full_name: Fuchs, C.
last_name: Fuchs
- first_name: K.
full_name: Volz, K.
last_name: Volz
- first_name: F.
full_name: Dobener, F.
last_name: Dobener
- first_name: M.
full_name: Stein, M.
last_name: Stein
- first_name: Torsten
full_name: Meier, Torsten
id: '344'
last_name: Meier
orcid: 0000-0001-8864-2072
- first_name: S.
full_name: Chatterjee, S.
last_name: Chatterjee
citation:
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
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
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} }'
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.
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.'
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.
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).
date_created: 2024-07-15T09:47:27Z
date_updated: 2024-07-15T09:49:41Z
department:
- _id: '15'
- _id: '170'
- _id: '293'
- _id: '35'
- _id: '230'
- _id: '429'
- _id: '27'
doi: 10.1103/physrevb.109.075301
intvolume: ' 109'
issue: '7'
language:
- iso: eng
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
- _id: '53'
grant_number: '231447078'
name: 'TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden
Konzepten zu funktionellen Strukturen'
- _id: '165'
grant_number: '231447078'
name: 'TRR 142 - A10: TRR 142 - Nichtlinearitäten von atomar dünnen Übergangsmetall-Dichalkogeniden
in starken Feldern (A10)'
publication: Physical Review B
publication_identifier:
issn:
- 2469-9950
- 2469-9969
publication_status: published
publisher: American Physical Society (APS)
status: public
title: Optical Stark effect in type-II semiconductor heterostructures
type: journal_article
user_id: '16199'
volume: 109
year: '2024'
...
---
_id: '52700'
abstract:
- lang: eng
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.'
author:
- first_name: Viktor
full_name: Myroshnychenko, Viktor
id: '46371'
last_name: Myroshnychenko
- first_name: Pious Mathews
full_name: Mulavarickal Jose, Pious Mathews
last_name: Mulavarickal Jose
- first_name: Henna
full_name: Farheen, Henna
id: '53444'
last_name: Farheen
orcid: 0000-0001-7730-3489
- first_name: Shafaq
full_name: Ejaz, Shafaq
last_name: Ejaz
- first_name: Christian
full_name: Brosseau, Christian
last_name: Brosseau
- first_name: Jens
full_name: Förstner, Jens
id: '158'
last_name: Förstner
orcid: 0000-0001-7059-9862
citation:
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'
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'
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} }'
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.'
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.'
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.'
short: V. Myroshnychenko, P.M. Mulavarickal Jose, H. Farheen, S. Ejaz, C. Brosseau,
J. Förstner, Physica Scripta 99 (2024) 045952.
date_created: 2024-03-21T10:34:48Z
date_updated: 2024-07-22T07:43:53Z
ddc:
- '530'
department:
- _id: '61'
- _id: '230'
doi: 10.1088/1402-4896/ad3172
file:
- access_level: open_access
content_type: application/pdf
creator: fossie
date_created: 2024-03-21T10:39:32Z
date_updated: 2024-03-21T10:39:32Z
file_id: '52701'
file_name: 2024-03 Myroshnychenko - Physica Scripta - From Swiss-cheese to discrete
ferroelectric.pdf
file_size: 5386508
relation: main_file
file_date_updated: 2024-03-21T10:39:32Z
has_accepted_license: '1'
intvolume: ' 99'
issue: '4'
keyword:
- tet_topic_ferro
language:
- iso: eng
oa: '1'
page: '045952'
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: Physica Scripta
publication_identifier:
issn:
- 0031-8949
- 1402-4896
publication_status: published
publisher: IOP Publishing
status: public
title: 'From Swiss-cheese to discrete ferroelectric composites: assessing the ferroelectric
butterfly shape in polarization loops'
type: journal_article
user_id: '158'
volume: 99
year: '2024'
...
---
_id: '46469'
abstract:
- lang: eng
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. '
article_number: '013104'
article_type: original
author:
- first_name: Christian
full_name: Offen, Christian
id: '85279'
last_name: Offen
orcid: 0000-0002-5940-8057
- first_name: Sina
full_name: Ober-Blöbaum, Sina
id: '16494'
last_name: Ober-Blöbaum
citation:
ama: Offen C, Ober-Blöbaum S. Learning of discrete models of variational PDEs from
data. Chaos. 2024;34(1). 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
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} }'
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.
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.'
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.
short: C. Offen, S. Ober-Blöbaum, Chaos 34 (2024).
date_created: 2023-08-10T08:24:48Z
date_updated: 2024-08-12T13:45:43Z
ddc:
- '510'
department:
- _id: '636'
doi: 10.1063/5.0172287
external_id:
arxiv:
- '2308.05082 '
file:
- access_level: open_access
content_type: application/pdf
creator: coffen
date_created: 2024-01-09T10:48:38Z
date_updated: 2024-01-09T10:48:38Z
file_id: '50376'
file_name: Accepted manuscript with AIP banner CHA23-AR-01370.pdf
file_size: 13222105
relation: main_file
title: Accepted Manuscript Chaos
- access_level: open_access
content_type: application/pdf
creator: coffen
date_created: 2024-01-09T11:19:49Z
date_updated: 2024-01-09T11:19:49Z
description: |-
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.
file_id: '50390'
file_name: LDensityPDE_AIP.pdf
file_size: 12960884
relation: main_file
title: Learning of discrete models of variational PDEs from data
file_date_updated: 2024-01-09T11:19:49Z
has_accepted_license: '1'
intvolume: ' 34'
issue: '1'
language:
- iso: eng
oa: '1'
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication: Chaos
publication_identifier:
issn:
- 1054-1500
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
related_material:
link:
- description: GitHub
relation: software
url: https://github.com/Christian-Offen/DLNN_pde
status: public
title: Learning of discrete models of variational PDEs from data
type: journal_article
user_id: '85279'
volume: 34
year: '2024'
...
---
_id: '55159'
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."
author:
- first_name: Christian
full_name: Offen, Christian
id: '85279'
last_name: Offen
orcid: 0000-0002-5940-8057
citation:
ama: Offen C. Machine learning of discrete field theories with guaranteed convergence
and uncertainty quantification.
apa: Offen, C. (n.d.). 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}
}'
chicago: Offen, Christian. “Machine Learning of Discrete Field Theories with Guaranteed
Convergence and Uncertainty Quantification,” n.d.
ieee: C. Offen, “Machine learning of discrete field theories with guaranteed convergence
and uncertainty quantification.” .
mla: Offen, Christian. Machine Learning of Discrete Field Theories with Guaranteed
Convergence and Uncertainty Quantification.
short: C. Offen, (n.d.).
date_created: 2024-07-10T13:43:50Z
date_updated: 2024-08-12T13:43:32Z
ddc:
- '510'
department:
- _id: '636'
external_id:
arxiv:
- '2407.07642'
file:
- access_level: open_access
content_type: application/pdf
creator: coffen
date_created: 2024-07-10T13:39:32Z
date_updated: 2024-07-10T13:39:32Z
description: |-
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.
Moreover, 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.
The 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.
file_id: '55160'
file_name: L_Collocation.pdf
file_size: 4569314
relation: main_file
title: Machine learning of discrete field theories with guaranteed convergence and
uncertainty quantification
file_date_updated: 2024-07-10T13:39:32Z
has_accepted_license: '1'
keyword:
- System identification
- inverse problem of variational calculus
- Gaussian process
- Lagrangian learning
- physics informed machine learning
- geometry aware learning
language:
- iso: eng
oa: '1'
page: '28'
project:
- _id: '52'
name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing'
publication_status: submitted
related_material:
link:
- description: GitHub
relation: software
url: https://github.com/Christian-Offen/Lagrangian_GP_PDE
status: public
title: Machine learning of discrete field theories with guaranteed convergence and
uncertainty quantification
type: preprint
user_id: '85279'
year: '2024'
...