Dr. rer. nat. Dimitrios Karachalios
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Research Scientist
Institute for Electrical Engineering in Medicine
Universität zu Lübeck
Moislinger Allee 53-55
23558 Lübeck
Gebäude 19
Email: | dimitrios.karachalios(at)uni-luebeck.de |
Phone: | +49 451 3101 6235 |
Research
Research Interests
- Data-Driven modeling
- Nonlinear system identification
- Model order reduction
- Model predictive control
- Linear parameter-varying control systems
Current Projects
- Practical model predictive control for nonlinear/time-varying systems using linear-parameter varying models (DFG Proj. No. 419290163)
Curriculum Vitae
Dimitrios S. Karachalios completed his diploma in applied mathematics and physical sciences from the National Technical University of Athens (NTUA) with statistics and computer science directions, including a year M.Sc. in 2012. Continuously, he received a second M.Sc. degree in computational mechanics in fluid flow from the NTUA in 2015. After working experience and army obligations, he joined 2017 the Max Planck Institute for Dynamics of Complex Technical Systems in Magdeburg, Germany, for his doctoral studies on data-driven nonlinear system reduction and identification. Since October 2022, he has been a research scientist with the Institute for Electrical Engineering in Medicine, working on nonlinear model predictive control.
Teaching (Assistant)
- Advanced numerical linear algebra (Otto von Guericke University, Magdeburg, summer semester 2022)
Publications
2025
Data-Driven Quadratic Modeling in the Loewner Framework from Input-Output Time-Domain Measurements, SIAM Journal on Applied Dynamical Systems , vol. 24, no. 1, pp. 457-500, 2025.
DOI: | 10.1137/22M153567X |
File: | 22M153567X |
Bibtex: | ![]() @article{doi:10.1137/22M153567X, author = {Karachalios, D. S. and Gosea, I. V. and Gkimisis, L. and Antoulas, A. C.}, title = {Data-Driven Quadratic Modeling in the Loewner Framework from Input-Output Time-Domain Measurements}, journal = {SIAM Journal on Applied Dynamical Systems}, volume = {24}, number = {1}, pages = {457-500}, year = {2025}, doi = {10.1137/22M153567X}, URL = { https://doi.org/10.1137/22M153567X }, eprint = { https://doi.org/10.1137/22M153567X}, abstract = { Abstract.In this study, we present a purely data-driven method that uses the Loewner framework along with nonlinear optimization techniques to infer quadratic dynamical systems with affine control that admit Volterra series (VS) representations from input-output time-domain measurements. The proposed method extensively employs optimization tools for interpolating the symmetric generalized frequency response functions (GFRFs) derived in the VS framework. The GFRF estimations are obtained from the Fourier spectrum (phase and amplitude) of the quasi-steady-state system response under harmonic excitation. Appropriate treatment of these measurements under the developed framework allows the identification of low-order in-state dimension quadratic state-space models with nontrivial stable equilibria, such as in the Lorenz ’63 forced system. We thus can achieve low-order global model identification for certain classes of systems that can bifurcate to multiple equilibria after collecting measurements solely from a local stable operational regime. The advanced framework rigorously tests the identification and reduction features across various examples with increasing dimensions and varying complexities. It effectively addresses the inference of a reduced model from measurements of a viscous flow, assuming adherence to the Burgers’ model with Robin boundary conditions. These results provide new prospects for developing low-order predictive models based on input-output data suitable for control. } } |
2024
Bilinear Realization from I/O Data with NNs, in Scientific Computing in Electrical Engineering , van Beurden, Martijn and Budko, Neil V. and Ciuprina, Gabriela and Schilders, Wil and Bansal, Harshit and Barbulescu, Ruxandra, Eds. Cham: Springer Nature Switzerland, 2024. pp. 184--192.
ISBN: | 978-3-031-54517-7 |
Closed-Loop Identification and Tracking Control of a Ballbot, in 2024 IEEE Conference on Control Technology and Applications (CCTA) , 2024. pp. 337-342.
DOI: | 10.1109/CCTA60707.2024.10666565 |
Error Bounds in Nonlinear Model Predictive Control with Linear Differential Inclusions of Parametric-Varying Embeddings, in 2024 18th International Conference on Control, Automation, Robotics and Vision (ICARCV) , 2024. pp. 866-871.
DOI: | 10.1109/ICARCV63323.2024.10821691 |
Parameter Refinement of a Ballbot and Predictive Control for Reference Tracking with Linear Parameter-Varying Embedding, in 2024 IEEE Conference on Control Technology and Applications (CCTA) , 2024. pp. 688-693.
DOI: | 10.1109/CCTA60707.2024.10666650 |
Stochastic Error Bounds in Nonlinear Model Predictive Control with Gaussian Processes via Parameter-Varying Embeddings, in 2024 18th International Conference on Control, Automation, Robotics and Vision (ICARCV) , 2024. pp. 860-865.
DOI: | 10.1109/ICARCV63323.2024.10821629 |
2023
A data-driven nonlinear frequency response approach based on the Loewner framework: preliminary analysis, IFAC-PapersOnLine , vol. 56, no. 1, pp. 234-239, 2023.
DOI: | https://doi.org/10.1016/j.ifacol.2023.02.040 |
File: | S2405896323002288 |
Bibtex: | ![]() @article{GOSEA2023234, title = {A data-driven nonlinear frequency response approach based on the Loewner framework: preliminary analysis}, journal = {IFAC-PapersOnLine}, volume = {56}, number = {1}, pages = {234-239}, year = {2023}, note = {12th IFAC Symposium on Nonlinear Control Systems NOLCOS 2022}, issn = {2405-8963}, doi = {https://doi.org/10.1016/j.ifacol.2023.02.040}, url = {https://www.sciencedirect.com/science/article/pii/S2405896323002288}, author = {Ion Victor Gosea and Luka A. Živković and Dimitrios S. Karachalios and Tanja Vidaković-Koch and Athanasios C. Antoulas}, keywords = {Data-Driven Methods, Nonlinear Dynamics, Nonlinear Frequency Response, Transfer Functions, Frequency Response Functions, Model Reduction, Non-intrusive Approach} } |
Error Bounds in Nonlinear Model Predictive Control with Linear Differential Inclusions of Parametric-Varying Embeddings, 2023.
On the Design of Nonlinear MPC and LPVMPC for Obstacle Avoidance in Autonomous Driving, in International Conference on Control, Decision and Information Technologies (CoDIT)(accepted) , Italy , 2023.
Weblink: | https://arxiv.org/pdf/2307.06031.pdf |
Bibtex: | ![]() @Inproceedings{Nezami2023, author = {Maryam Nezami and Dimitrios S. Karachalios and Georg Schildbach and Hossam S. Abbas}, title = {On the Design of Nonlinear MPC and LPVMPC for Obstacle Avoidance in Autonomous Driving}, booktitle = {International Conference on Control, Decision and Information Technologies (CoDIT)(accepted)}, year = {2023}, month = {July}, address = {Italy} url = {https://arxiv.org/pdf/2307.06031.pdf} } |
2022
Data-driven quadratic modeling in the Loewner framework, 2022. arXiv.
DOI: | 10.48550/ARXIV.2211.10635 |
File: | 2211.10635 |
Bibtex: | ![]() @misc{KGGA2022, doi = {10.48550/ARXIV.2211.10635}, url = {https://arxiv.org/abs/2211.10635}, author = {Karachalios, D. S. and Gosea, I. V. and Gkimisis, L. and Antoulas, A. C.}, keywords = {Dynamical Systems (math.DS), FOS: Mathematics, FOS: Mathematics, 93B15, 93C15, 93C10, 65F45}, title = {Data-driven quadratic modeling in the Loewner framework}, publisher = {arXiv}, note = {Submitted to SIADS Journal 17.11.2022, status: In Review}, year = {2022}, copyright = {arXiv.org perpetual, non-exclusive license} } |
Bilinear realization from input-output data with neural networks, 2022.
A framework for fitting quadratic-bilinear systems with applications to models of electrical circuits, IFAC-PapersOnLine , vol. 55, no. 20, pp. 7-12, 2022.
DOI: | https://doi.org/10.1016/j.ifacol.2022.09.064 |
File: | S2405896322012459 |
Bibtex: | ![]() @article{KARACHALIOS20227, title = {A framework for fitting quadratic-bilinear systems with applications to models of electrical circuits}, journal = {IFAC-PapersOnLine}, volume = {55}, number = {20}, pages = {7-12}, year = {2022}, note = {10th Vienna International Conference on Mathematical Modelling MATHMOD 2022}, issn = {2405-8963}, doi = {https://doi.org/10.1016/j.ifacol.2022.09.064}, url = {https://www.sciencedirect.com/science/article/pii/S2405896322012459}, author = {Dimitrios S. Karachalios and Ion Victor Gosea and Athanasios C. Antoulas}, keywords = {Data-Driven, Non-Intrusive Modeling, Model Order Reduction, Nonlinear Dynamics, Quadratic-Bilinear Systems, System Identification, Lift, Learn Approach} } |
2021
Mitteilungen der Deutschen Mathematiker-Vereinigung , vol. 29, no. 4, pp. 198--204, 2021.
DOI: | doi:10.1515/dmvm-2021-0075 |
File: | dmvm-2021-0075 |
Bibtex: | ![]() @article{BennerFilanovaKarachaliosMonemAbdelhafezPrzybillaWerner+2021+198+204, url = {https://doi.org/10.1515/dmvm-2021-0075}, title = {Mathematische Komplexitätsreduktion: Modellreduktion dynamischer Systeme}, title = {}, author = {Peter Benner and Yevgeniya Filanova and Dimitrios Karachalios and Shaimaa Monem Abdelhafez and Jennifer Przybilla and Steffen W. R. Werner}, pages = {198--204}, volume = {29}, number = {4}, journal = {Mitteilungen der Deutschen Mathematiker-Vereinigung}, doi = {doi:10.1515/dmvm-2021-0075}, year = {2021}, lastchecked = {2023-04-17} } |
6 The Loewner framework for system identification and reduction, in Volume 1 System- and Data-Driven Methods and Algorithms , Peter Benner and Stefano Grivet-Talocia and Alfio Quarteroni and Gianluigi Rozza and Wil Schilders and Luís Miguel Silveira, Eds. Berlin, Boston: De Gruyter, 2021, pp. 181--228.
DOI: | doi:10.1515/9783110498967-006 |
ISBN: | 9783110498967 |
File: | 9783110498967-006 |
Bibtex: | ![]() @inbook{KarachaliosGoseaAntoulas+2021+181+228, url = {https://doi.org/10.1515/9783110498967-006}, title = {6 The Loewner framework for system identification and reduction}, booktitle = {Volume 1 System- and Data-Driven Methods and Algorithms}, author = {Dimitrios S. Karachalios and Ion Victor Gosea and Athanasios C. Antoulas}, editor = {Peter Benner and Stefano Grivet-Talocia and Alfio Quarteroni and Gianluigi Rozza and Wil Schilders and Luís Miguel Silveira}, publisher = {De Gruyter}, address = {Berlin, Boston}, pages = {181--228}, doi = {doi:10.1515/9783110498967-006}, isbn = {9783110498967}, year = {2021}, lastchecked = {2023-04-17} } |
Data-driven (Bilinear) identification and reduction, PAMM , vol. 20, no. S1, pp. e202000346, 2021.
DOI: | https://doi.org/10.1002/pamm.202000346 |
File: | pamm.202000346 |
Bibtex: | ![]() @article{https://doi.org/10.1002/pamm.202000346, author = {Karachalios, Dimitrios S. and Gosea, Ion Victor and Antoulas, Athanasios C.}, title = {Data-driven (Bilinear) identification and reduction}, journal = {PAMM}, volume = {20}, number = {S1}, pages = {e202000346}, doi = {https://doi.org/10.1002/pamm.202000346}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pamm.202000346}, eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/pamm.202000346}, year = {2021} } |
Learning reduced-order models of quadratic dynamical systems from input-output data, in 2021 European Control Conference (ECC) , 2021. pp. 1426-1431.
DOI: | 10.23919/ECC54610.2021.9654993 |
Bibtex: | ![]() @INPROCEEDINGS{9654993, author={Gosea, Ion Victor and Karachalios, Dimitrios S. and Antoulas, Athanasios C.}, booktitle={2021 European Control Conference (ECC)}, title={Learning reduced-order models of quadratic dynamical systems from input-output data}, year={2021}, volume={}, number={}, pages={1426-1431}, doi={10.23919/ECC54610.2021.9654993} } |
Mathematische Komplexitätsreduktion: Modellreduktion dynamischer Systeme, Mitteilungen der Deutschen Mathematiker-Vereinigung , vol. 29, no. 4, pp. 198--204, 2021.
DOI: | doi:10.1515/dmvm-2021-0075 |
File: | dmvm-2021-0075 |
Bibtex: | ![]() @article{BennerFilanovaKarachaliosMonemAbdelhafezPrzybillaWerner+2021+198+204, url = {https://doi.org/10.1515/dmvm-2021-0075}, title = {Mathematische Komplexitätsreduktion: Modellreduktion dynamischer Systeme}, title = {}, author = {Peter Benner and Yevgeniya Filanova and Dimitrios Karachalios and Shaimaa Monem Abdelhafez and Jennifer Przybilla and Steffen W. R. Werner}, pages = {198--204}, volume = {29}, number = {4}, journal = {Mitteilungen der Deutschen Mathematiker-Vereinigung}, doi = {doi:10.1515/dmvm-2021-0075}, year = {2021}, lastchecked = {2023-04-17} } |
On Bilinear Time-Domain Identification and Reduction in the Loewner Framework, in Model Reduction of Complex Dynamical Systems , Benner, Peter and Breiten, Tobias and Faßbender, Heike and Hinze, Michael and Stykel, Tatjana and Zimmermann, Ralf, Eds. Cham: Springer International Publishing, 2021, pp. 3-30.
DOI: | 10.1007/978-3-030-72983-7_1 |
File: | 978-3-030-72983-7_1 |
Bibtex: | ![]() @Inbook{Karachalios2021, author="Karachalios, D. S. and Gosea, I. V. and Antoulas, A. C.", editor="Benner, Peter and Breiten, Tobias and Fa{\ss}bender, Heike and Hinze, Michael and Stykel, Tatjana and Zimmermann, Ralf", title="On Bilinear Time-Domain Identification and Reduction in the Loewner Framework", bookTitle="Model Reduction of Complex Dynamical Systems", year={2021}, publisher="Springer International Publishing", address="Cham", pages="3--30", doi="10.1007/978-3-030-72983-7_1", url="https://doi.org/10.1007/978-3-030-72983-7_1" } |
On computing reduced-order bilinear models from time-domain data, PAMM , vol. 21, no. 1, pp. e202100254, 2021.
DOI: | https://doi.org/10.1002/pamm.202100254 |
File: | pamm.202100254 |
Bibtex: | ![]() @article{https://doi.org/10.1002/pamm.202100254, author = {Gosea, Ion Victor and Karachalios, Dimitrios S. and Antoulas, Athanasios C.}, title = {On computing reduced-order bilinear models from time-domain data}, journal = {PAMM}, volume = {21}, number = {1}, pages = {e202100254}, doi = {https://doi.org/10.1002/pamm.202100254}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pamm.202100254}, eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/pamm.202100254}, year = {2021} } |
The Loewner framework for nonlinear identification and reduction of Hammerstein cascaded dynamical systems, PAMM , vol. 20, no. 1, pp. e202000337, 2021.
DOI: | https://doi.org/10.1002/pamm.202000337 |
File: | pamm.202000337 |
Bibtex: | ![]() @article{https://doi.org/10.1002/pamm.202000337, author = {Karachalios, Dimitrios S. and Gosea, Ion Victor and Antoulas, Athanasios C.}, title = {The Loewner framework for nonlinear identification and reduction of Hammerstein cascaded dynamical systems}, journal = {PAMM}, volume = {20}, number = {1}, pages = {e202000337}, doi = {https://doi.org/10.1002/pamm.202000337}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pamm.202000337}, eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/pamm.202000337}, year = {2021} } |
2019
A bilinear identification-modeling framework from time domain data, PAMM , vol. 19, no. 1, pp. e201900246, 2019.
DOI: | https://doi.org/10.1002/pamm.201900246 |
File: | pamm.201900246 |
Bibtex: | ![]() @article{https://doi.org/10.1002/pamm.201900246, author = {Karachalios, Dimitrios S. and Gosea, Ion Victor and Antoulas, Athanasios C.}, title = {A bilinear identification-modeling framework from time domain data}, journal = {PAMM}, volume = {19}, number = {1}, pages = {e201900246}, doi = {https://doi.org/10.1002/pamm.201900246}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pamm.201900246}, eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/pamm.201900246}, year = {2019} } |
2018
Data-driven approximation methods applied to non-rational functions, PAMM , vol. 18, no. 1, pp. e201800368, 2018.
DOI: | https://doi.org/10.1002/pamm.201800368 |
File: | pamm.201800368 |
Bibtex: | ![]() @article{https://doi.org/10.1002/pamm.201800368, author = {Karachalios, Dimitrios S. and Gosea, Ion Victor and Antoulas, Athanasios C.}, title = {Data-driven approximation methods applied to non-rational functions}, journal = {PAMM}, volume = {18}, number = {1}, pages = {e201800368}, doi = {https://doi.org/10.1002/pamm.201800368}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pamm.201800368}, eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/pamm.201800368}, year = {2018} } |
2017
Case study: Approximations of the Bessel Function, 2017.
Conferences, Workshops and Talks
- (Contributed paper) July 03-06, 2023, 9th International Conference on Control, Decision and Information Technologies, Rome, Italy
- (Poster) September 19-23, 2022, Model Reduction and Surrogate Modeling (MORE), Berlin, Germany
- (Contributed talk) August 15-19, 2022, 92nd GAMM Annual Meeting, Aachen, Germany
- (Contributed paper) July 27-29, 2022, 10th International Conference on Mathematical Modelling, Vienna, Austria
- (Contributed paper and talk) July 11-14, 14th International Conference on Scientific Computing in Electrical Engineering (SCEE), Amsterdam, The Netherlands
- (Invited talk) June 20 - 26, 2021, 8th European Congress of Mathematics, Portoroz, Slovenia (virtual conference)
- (Contributed talk and paper) March 15-19, 2021, 91st GAMM Annual Meeting, Kassel, Germany (virtual conference)
- March 1-5, 2021, SIAM Conference on Computational Science and Engineering (CSE21), Texas, U.S. (virtual conference)
- (Poster) July 27-31, 2020, GAMM Summer School: Learning Models from Data: Model Reduction, System Identification, and Machine Learning
- (Contributed talk and paper) August 28-30, 2019, Model Reduction of Complex Dynamical Systems, Graz, Austria
- December 10-11, 2019, MathCoRe social skills course: Presentation skills by K. Raabe, NaWik
- November 6, 2019, MathCoRe lecture: Good Scientific Practice by B. Witter, OVGU Graduate Academy
- (Contributed talk) September 23-27, 2019, Model Order Reduction Summer School, Eindhoven, The Netherlands
- (Poster presentation) May 13-14, 2019, MathCoRe annual colloquium in Wernigerode, Germany
- (Contributed talk and paper) February 18-22, 2019, 90th GAMM Annual Meeting, Vienna, Austria
- (Contributed talk and paper) March 19-23, 2018, 89th GAMM Annual Meeting, Munich, Germany
- (Contributed talk) February 26- March 1, 2018, 12th Elgersburg Workshop on control, Elgersburg, Germany
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