Dr. rer. nat. Dimitrios Karachalios

Photo of Dimitrios  Karachalios

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

D. S. Karachalios, I. V. Gosea, L. Gkimisis, and A. C. Antoulas,
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: 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

D. S. Karachalios, I. V. Gosea, K. Kour, and A. C. Antoulas,
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
Tobias Fischer, Dimitrios S. Karachalios, Ievgen Zhavzharov, and Hossam S. Abbas,
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
Dimitrios S. Karachalios, Maryam Nezami, Georg Schildbach, and Hossam S. Abbas,
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
Dimitrios S. Karachalios, and Hossam S. Abbas,
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
Dimitrios S. Karachalios, and Hossam S. Abbas,
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

Ion Victor Gosea, Luka A. Živković, Dimitrios S. Karachalios, Tanja Vidaković-Koch, and Athanasios C. Antoulas,
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: 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}
}
Dimitrios S. Karachalios, Maryam Nezami, Georg Schildbach, and Hossam S. Abbas,
Error Bounds in Nonlinear Model Predictive Control with Linear Differential Inclusions of Parametric-Varying Embeddings, 2023.
Bibtex: BibTeX
@misc{karachalios2023error,
      title = {Error Bounds in Nonlinear Model Predictive Control with Linear Differential Inclusions of Parametric-Varying Embeddings}, 
      author={Dimitrios S. Karachalios and Maryam Nezami and Georg Schildbach and Hossameldin S. Abbas},
      year={2023},
      eprint={2310.01049},
      archivePrefix={arXiv},
      primaryClass={math.OC}
}
Maryam Nezami, Dimitrios S. Karachalios, Georg Schildbach, and Hossam S. Abbas,
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: 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

I. V. Gosea, L. Gkimisis, A. C. Antoulas, and Dimitrios Karachalios,
Data-driven quadratic modeling in the Loewner framework, 2022. arXiv.
DOI:10.48550/ARXIV.2211.10635
File: 2211.10635
Bibtex: 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}
}
Dimitrios S. Karachalios, Ion Victor Gosea, Kirandeep Kour, and Athanasios C. Antoulas,
Bilinear realization from input-output data with neural networks, 2022.
Bibtex: BibTeX
@misc{karachalios2022bilinear,
      title={Bilinear realization from input-output data with neural networks}, 
      author={Dimitrios S. Karachalios and Ion Victor Gosea and Kirandeep Kour and Athanasios C. Antoulas},
      year={2022},
      eprint={2208.10124},
      archivePrefix={arXiv},
      primaryClass={math.DS}
}
Dimitrios S. Karachalios, Ion Victor Gosea, and Athanasios C. Antoulas,
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: 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

Peter Benner, Yevgeniya Filanova, Dimitrios Karachalios, Shaimaa Monem Abdelhafez, Jennifer Przybilla, and Steffen W. R. Werner,
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: 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}
}
Dimitrios S. Karachalios, Ion Victor Gosea, and Athanasios C. Antoulas,
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: 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}
}
Dimitrios S. Karachalios, Ion Victor Gosea, and Athanasios C. Antoulas,
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: 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}
}
Ion Victor Gosea, Dimitrios S. Karachalios, and Athanasios C. Antoulas,
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: 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}
}
Peter Benner, Yevgeniya Filanova, Dimitrios Karachalios, Shaimaa Monem Abdelhafez, Jennifer Przybilla, and Steffen W. R. Werner,
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: 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}
}
D. S. Karachalios, I. V. Gosea, and A. C. Antoulas,
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: 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"
}
Ion Victor Gosea, Dimitrios S. Karachalios, and Athanasios C. Antoulas,
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: 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}
}
Dimitrios S. Karachalios, Ion Victor Gosea, and Athanasios C. Antoulas,
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: 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

Dimitrios S. Karachalios, Ion Victor Gosea, and Athanasios C. Antoulas,
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: 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

Dimitrios S. Karachalios, Ion Victor Gosea, and Athanasios C. Antoulas,
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: 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

D. S. Karachalios, I. V. Gosea, Q. Zhang, and A. C. Antoulas,
Case study: Approximations of the Bessel Function, 2017.
Bibtex: BibTeX
@misc{karachalios2017case,
      title={Case study: Approximations of the Bessel Function}, 
      author={D. S. Karachalios and I. V. Gosea and Q. Zhang and A. C. Antoulas},
      year={2017},
      eprint={1801.03390},
      archivePrefix={arXiv},
      primaryClass={math.NA}
}

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