This image shows Benjamin  Unger

Benjamin Unger

Dr.

Dynamical Systems
Independent Junior Research Group Leader
[Photo: SimTech/Max Kovalenko]

Contact

Universitätsstraße 32
70569 Stuttgart
Deutschland
Room: 02.324

Office Hours

Consultation by appointment

Subject

  • Model order reduction
  • Data-driven surrogate models
  • Delay differential-algebraic equations
  • Port-Hamiltonian systems
  • Digital Twins and Physics-informed machine learning
  1. 2023

    1. V. Mehrmann and B. Unger, “Control of port-Hamiltonian differential-algebraic systems and applications,” Acta Numerica, vol. 32, pp. 395–515, 2023, doi: 10.1017/S0962492922000083.
    2. T. Holicki, J. Nicodemus, P. Schwerdtner, and B. Unger, “Energy matching in reduced passive and port-Hamiltonian systems,” 2023.
    3. R. Morandin, J. Nicodemus, and B. Unger, “Port-Hamiltonian Dynamic Mode Decomposition,” SIAM Journal on Scientific Computing, vol. 45, no. 4, Art. no. 4, Jul. 2023, doi: 10.1137/22m149329x.
  2. 2022

    1. V. Mehrmann and B. Unger, “Control of port-Hamiltonian differential-algebraic systems and applications,” ArXiv e-print 2201.06590, 2022, [Online]. Available: http://arxiv.org/abs/2201.06590
    2. F. Black, P. Schulze, and B. Unger, “Modal Decomposition of Flow Data via Gradient-Based Transport Optimization,” in Active Flow and Combustion Control 2021, R. King and D. Peitsch, Eds., in Active Flow and Combustion Control 2021. Cham: Springer International Publishing, 2022, pp. 203–224. doi: 10.1007/978-3-030-90727-3_13.
    3. T. Breiten, D. Hinsen, and B. Unger, “Towards a modeling class for port-Hamiltonian systems with time-delay,” 2022. doi: 10.48550/arXiv.2211.10687.
    4. D. Frank, D. A. Latif, M. Muehlebach, B. Unger, and S. Staab, “Robust Recurrent Neural Network to Identify Ship Motion in Open Water with Performance Guarantees,” Publication, 2022. doi: 10.48550/arXiv.2212.05781.
    5. J. Heiland and B. Unger, “Identification of Linear Time-Invariant Systems with Dynamic Mode Decomposition,” Mathematics, vol. 10, no. 3, Art. no. 3, 2022, doi: 10.3390/math10030418.
    6. B. Hillebrecht and B. Unger, “Certified machine learning: A posteriori error estimation for physics-informed neural networks,” ArXiv e-print 2203.17055, 2022, [Online]. Available: http://arxiv.org/abs/2203.17055
    7. B. Hillebrecht and B. Unger, “Certified machine learning: Rigorous a posteriori error bounds for PDE defined PINNs,” 2022.
    8. T. Breiten and B. Unger, “Passivity preserving model reduction via spectral factorization,” Automatica, vol. 142, p. 110368, Aug. 2022, doi: 10.1016/j.automatica.2022.110368.
    9. B. Hillebrecht and B. Unger, “Certified machine learning: A posteriori error estimation for physics-informed neural networks,” in 2022 International Joint Conference on Neural Networks (IJCNN), in 2022 International Joint Conference on Neural Networks (IJCNN). IEEE, Jul. 2022, pp. 1–8. doi: 10.1109/ijcnn55064.2022.9892569.
    10. J. Nicodemus, J. Kneifl, J. Fehr, and B. Unger, “Physics-informed Neural Networks-based Model Predictive Control for Multi-link Manipulators,” IFAC-PapersOnLine, vol. 55, no. 20, Art. no. 20, 2022, doi: 10.1016/j.ifacol.2022.09.117.
    11. R. Morandin, J. Nicodemus, and B. Unger, “Port-Hamiltonian Dynamic Mode Decomposition,” ArXiv e-print 2204.13474, 2022, doi: 10.48550/arXiv.2204.13474.
    12. R. Altmann, R. Maier, and B. Unger, “Semi-explicit integration of second order for weakly coupled poroelasticity,” ArXiv e-print 2203.16664, 2022, [Online]. Available: http://arxiv.org/abs/2203.16664
  3. 2021

    1. R. Altmann, R. Maier, and B. Unger, “Semi-explicit discretization schemes for weakly coupled elliptic-parabolic problems,” Mathematics of Computation, vol. 90, no. 329, Art. no. 329, 2021, doi: 10.1090/mcom/3608.
    2. F. Black, P. Schulze, and B. Unger, “Decomposition of flow data via gradient-based transport optimization,” ArXiv e-print 2107.03481, 2021, [Online]. Available: https://arxiv.org/abs/2107.03481
    3. I. Ahrens and B. Unger, “A simple success check for delay differential-algebraic equations,” in Proceedings in Applied Mathematics and Mechanics 2020, in Proceedings in Applied Mathematics and Mechanics 2020, vol. 20. Wiley, 2021, p. e202000270. doi: 10.1002/pamm.202000270.
    4. F. Black, P. Schulze, and B. Unger, “Efficient Wildland Fire Simulation via Nonlinear Model Order Reduction,” Fluids, vol. 6, no. 8, Art. no. 8, 2021, doi: 10.3390/fluids6080280.
    5. I. V. Gosea, S. Gugercin, and B. Unger, “Parametric model reduction via rational interpolation along parameters,” in 2021 60th IEEE Conference on Decision and Control (CDC), in 2021 60th IEEE Conference on Decision and Control (CDC). 2021, pp. 6895–6900. doi: 10.1109/CDC45484.2021.9682841.
    6. I. V. Gosea, S. Gugercin, and B. Unger, “Parametric model reduction via rational interpolation along parameters,” ArXiv e-print 2104.01016, 2021, [Online]. Available: https://arxiv.org/abs/2104.01016
    7. J. Heiland and B. Unger, “Identification of linear time-invariant systems with Dynamic Mode Decomposition,” ArXiv e-print 2109.06765, 2021, [Online]. Available: https://arxiv.org/abs/2109.06765
    8. R. Altmann, V. Mehrmann, and B. Unger, “Port-Hamiltonian formulations of poroelastic network models,” Mathematical and Computer Modelling of Dynamical Systems, vol. 27, no. 1, Art. no. 1, 2021, doi: 10.1080/13873954.2021.1975137.
    9. F. Black, P. Schulze, and B. Unger, “Model order reduction with dynamically transformed modes for the wave equation,” in Proceedings in Applied Mathematics and Mechanics 2020, in Proceedings in Applied Mathematics and Mechanics 2020, vol. 20. Wiley, 2021, p. e202000321. doi: 10.1002/pamm.202000321.
    10. F. Black, P. Schulze, and B. Unger, “Efficient Wildland Fire Simulation via Nonlinear Model Order Reduction,” ArXiv e-print 2106.11381, 2021, [Online]. Available: https://arxiv.org/abs/2106.11381
    11. S. Trenn and B. Unger, “Unimodular transformations for DAE initial trajectory problems,” in Proceedings in Applied Mathematics and Mechanics 2020, in Proceedings in Applied Mathematics and Mechanics 2020, vol. 20. Wiley, 2021, p. e202000322. doi: 10.1002/pamm.202000322.
    12. R. Altmann, R. Maier, and B. Unger, “A semi-explicit integration scheme for weakly-coupled poroelasticity with nonlinear permeability,” in Proceedings in Applied Mathematics and Mechanics 2020, in Proceedings in Applied Mathematics and Mechanics 2020, vol. 20. Wiley, 2021, p. e202000061. doi: 10.1002/pamm.202000061.
    13. T. Breiten and B. Unger, “Passivity preserving model reduction via spectral factorization,” ArXiv e-print 2103.13194, 2021, [Online]. Available: https://arxiv.org/abs/2103.13194
    14. J. Nicodemus, J. Kneifl, J. Fehr, and B. Unger, “Physics-informed Neural Networks-based Model Predictive Control for Multi-link Manipulators,” ArXiv e-print 2109.10793, 2021, [Online]. Available: https://arxiv.org/abs/2109.10793
  4. 2020

    1. I. Ahrens and B. Unger, “The Pantelides algorithm for delay differential-algebraic equations,” Transactions of Mathematics and Its Application, vol. 4, no. 1, Art. no. 1, 2020, doi: 10.1093/imatrm/tnaa003.
    2. R. Altmann, R. Maier, and B. Unger, “Semi-explicit discretization schemes for weakly coupled elliptic-parabolic problems,” Mathematics of Computation, p. 1, Oct. 2020, doi: 10.1090/mcom/3608.
    3. F. Black, P. Schulze, and B. Unger, “Projection-based model reduction with dynamically transformed modes,” ESAIM: Mathematical Modelling and Numerical Analysis, vol. 54, no. 6, Art. no. 6, Oct. 2020, doi: 10.1051/m2an/2020046.
    4. R. Altmann, V. Mehrmann, and B. Unger, “Port-Hamiltonian formulations of poroelastic network models,” ArXiv e-print 2012.01949, Dec. 2020, [Online]. Available: https://arxiv.org/abs/2012.01949
    5. B. Unger, “Delay differential-algebraic equations in real-time dynamic substructuring,” ArXiv e-print 2003.10195, Mar. 2020, [Online]. Available: https://arxiv.org/abs/2003.10195
  5. 2019

    1. S. Trenn and B. Unger, “Delay regularity of differential-algebraic equations,” in 2019 IEEE 58th Conference on Decision and Control (CDC), in 2019 IEEE 58th Conference on Decision and Control (CDC). Dec. 2019, pp. 989–994. doi: 10.1109/CDC40024.2019.9030146.
    2. E. Fosong, P. Schulze, and B. Unger, “From Time-Domain Data to Low-Dimensional Structured Models,” ArXiv e-print 1902.05112, Feb. 2019, [Online]. Available: https://arxiv.org/abs/1902.05112
    3. B. Unger and S. Gugercin, “Kolmogorov n-widths for linear dynamical systems,” Advances in Computational Mathematics, vol. 45, no. 5, Art. no. 5, Dec. 2019, doi: 10.1007/s10444-019-09701-0.
    4. D. Kern, M. Bartelt, and B. Unger, “How to write an article for GAMMAS and a longer title,” GAMM Archive for Students, vol. 1, no. 1, Art. no. 1, Feb. 2019, doi: 10.14464/gammas.v1i1.417.
  6. 2018

    1. P. Schulze, B. Unger, Christopher. Beattie, and S. Gugercin, “Data-driven Structured Realization,” Linear Algebra and its Applications, vol. 537, pp. 250–286, 2018, doi: 10.1016/j.laa.2017.09.030.
    2. P. Schulze and B. Unger, “Model reduction for linear systems with low-rank switching.,” SIAM J. Control and Optimization, vol. 56, no. 6, Art. no. 6, 2018, doi: 10.1137/18M1167887.
    3. B. Unger, “Discontinuity Propagation in Delay Differential-Algebraic Equations,” The Electronic Journal of Linear Algebra, vol. 34, pp. 582–601, Feb. 2018, doi: 10.13001/1081-3810.3759.
  7. 2016

    1. P. Schulze and B. Unger, “Data-driven interpolation of dynamical systems with delay.,” Systems Control Lett., vol. 97, pp. 125–131, 2016, doi: 10.1016/j.sysconle.2016.09.007.
  8. 2015

    1. V. Mehrmann and B. Unger, “Index preserving polynomial representation of nonlinear differential-algebraic systems,” Institut für Mathematik, TU Berlin, Str. des 17. Juni 136, D-10623 Berlin, FRG, Preprint 2--2015, 2015. [Online]. Available: http://www3.math.tu-berlin.de/cgi-bin/IfM/show_abstract.cgi?Report-02-2015.rdf.html
  9. 2013

    1. B. Unger, “Impact of Discretization Techniques on Nonlinear Model Reduction and Analysis of the Structure of the POD Basis,” Master’s Thesis, Virginia Polytechnic and State University, Blacksburg, Virginia, USA, 2013. [Online]. Available: https://vtechworks.lib.vt.edu/handle/10919/24197
  • Artificial intelligence meets molecular dynamics: certified machine learning for resolution transformation
    Together with Dr. K. Pluhackova, Aug. 2021 – Dez. 2023
  • Decoupling integration schemes of higher order for poroelastic networks
    Together with Dr. habil. R. Altmann, Oct. 2021 – Sept. 2024
  • Data-Integrated Low-Dimensional Surrogate Models with Guarantees
    June 2021 – Oct. 2024

Invited Talks

  • Model reduction for transport phenomena via state-dependent projections
    MOR Seminar (online), Universität Stuttgart, Apr. 2021.
  • Co-Design via port-Hamiltonian systems: advantages, challenges, and perspectives
    Workshop of the GAMM activity group on dynamics and control theory (online), Feb. 2021.
  • Structure-Preserving Model-Order Reduction for Port-Hamiltonian Systems
    Oberseminar Numerical Optimization (online), Universität Konstanz, Jan. 2021.
  • Kolmogorov n-widths and Hankel normapproximation
    Applied Numerical Analysis Seminar (Virginia Tech), Blacksburg, USA, Feb. 2017.

Minisymposium Talks

  • Model reduction for mixed data and first-principle models
    Mechanistic Machine Learning and Digital Twins for Computational Science, Engineering & Technology, San Diego, USA, Sept. 2021.
  • The Digital Twin Philosophy for Additive Manufacturing
    SIAM Conference on Computational Science and Engineering, online, Mar. 2021.
  • Nonlinear Galerkin model reduction for transport-dominated problems
    DMV Jahrestagung 2020, Chemnitz, Deutschland, Sept. 2020.
  • From Data to Structured Reduced-orderModels
    SIAM Conference on Computational Science and Engineering, Spokane, USA, Feb. 2019.
  • Well-posedness and numerical solution of nonlinear delay differential-algebraic equations
    International Conference on Scientific Computation and Differential Equations, Bath, UK, Sept. 2017.
  • Model Reduction, Transport Problems, and Structure
    SIAM Conference on Computational Science and Engineering, Atlanta, USA, Feb. 2017.
  • Structured surrogate models of complex dynamical systems based on input/output data
    7th European Congress ofMathematics (7ECM), Berlin, Germany, Juli 2016.
  • Structured input/output realization of dynamical systems
    20th Conference of the International Linear Algebra Society, Leuven, Belgium, July 2016.

Selected other talks and poster

  • Passivity preserving MOR via spectral factorization
    GAMM-Workshop 2021 -- Sion Digital online), Mar. 2021.
  • Asymptotic stability of neutral delay equations via semi-explicit time-integration
    GAMM Jahrestagung (online), Kassel, Germany, Mar. 2021.
  • Delay regularity of differential-algebraic equations
    58th IEEE Conference on Decision and Control, Nizza, France, Dec. 2019.
  • Model reduction for switched systems with low-rank switching (Poster)
    IUTAM Symposium on Model Order Reduction of Coupled Systems, Stuttgart, Germany, May 2018.
  • Delay Differential-Algebraic Equations: Primary Discontinuities and Regularization
    Analysis andNumerical Approximation ofConstrained Systems, Sion, Switzerland, April 2018.
  • Kolmogorov n-widths and optimal Hankel norm approximation
    GAMM Annual Meeting, Munich, Germany, March 2018
  • What is a well-posed delay differential-algebraic equation?
    Workshop on Control of Self-OrganizingNonlinear Systems Lutherstadt Wittenberg, Germany, Aug. 2017.
  • Nonintrusive Realization Theory for Structured Problems
    KoMSO Challenge Workshop Reduced-Order Modeling for Simulation and Optimization, Renningen, Germany, Nov. 2016.
  • Workshop: Trends on dissipativity in systems and control, Brig, Switzerland, May 2022 (together with T. Faulwasser and M. Voigt)
  • Conference session co-chair: GAMM Jahrestagung, Aachen, Aug. 2022, Session S20 Dynamics and Control (together with S. Grundel)
  • Conference: Energy-Based Modeling, Simulation, and Control of Complex Constrained Multiphysical Systems, CIRM, Luminy, France, April 2022 (together with P. Kotyzka, Y. Le Gorrec, B.Maschke, D.Matignon, J. Scherpen)
  • Minisymposium: Recent advances in model reduction and surrogate modeling,
    MATHMOD 2022, Vienna, Austria, February 2022 (together with T. Breiten, J. Fehr, S. Rave, J. Saak)
  • Minisymposium: Model order reduction and approximation of coupled systems,
    DMV Jahrestagung 2021 (online), Sept. 2021 (together with B. Lilljegren-Sailer)
  • Minisymposium: GAMM Juniors Poster Session,
    GAMM Jahrestagung 2021 (online), Mar. 2021
  • Minisymposium: Mathematical Aspects of the Digital Twin Modeling Paradigm, SIAM CSE 20201, virtual conference, March 2021 (together with P. Bürkner)
  • Minisymposium:NumericalMethods for port-Hamiltonian systems,DMVJahrestagung 2020, Chemnitz, Germany, Sept. 2020 (together with R. Altmann)
  • Conference: Meeting of the European SIAM and GAMM student chapters, Berlin, Germany, Sept. 2018 (together with D. Bankmann)
  • Young AcademicsMeetMentors (YAMM) Lunch, GAMMJahrestagung 2018,Munich, Germany, March 2018 (together with L. Pauli)
  • Minisymposium: Modeling and simulation of transport-dominated phenomena, 7ECM, July 2016, Berlin, Germany (together with C. Beattie, S. Gugercin, P. Schulze)
  • Conference: Energy Based Modeling, Simulation, and Control of Complex Physical Systems, April 2016, Berlin, Germany (together with V.Mehrmann, A.Miedlar, P. Schulze)
  • Summer school: Energy Based Modeling, Simulation, and Control of Complex Physical Systems, April 2016, Berlin, Germany (together with V.Mehrmann, A.Miedlar, P. Schulze)
  • Minisymposium: Simulation and control of delay differential-algebraic equations, SciCADE 2015, Sept. 2015, Potsdam, Germany (together with V.Mehrmann)
  • 16th IFACWorkshop on Time Delay Systems (TDS 2021)
    Associate Editor
  • GAMM Archive for Students
    Editor from 2018-2019, Founding Editor
  • Aug. 2019, Centre International De Rencontres Mathématiques, Lumini, France
    Research in Pairsmit Dr. R. Altmann and Dr. R. Maier
  • June 2018, University of Groningen, Groningen, Netherlands
    Invited by Prof. Dr. S. Trenn
  • Feb. 2017, Virginia Tech in Blacksburg, Virginia, USA
    Invited by Prof. Dr. S. Gugercin

Ph.D. students:

  • Birgit Hillebrecht, University of Stuttgart (since Nov. 2021)
  • Jonas Nicodemus, University of Stuttgart (since July 2021)
  • Abdullah Mujahid, Augsburg University and University of Stuttgart (since Nov. 2021)
  • Christian Pfaendner, University of Stuttgart (since Oct. 2021)

Master theses:

  • Abdullah Mujahid, Ruhr Universität Bochum
    Master thesis (Oct. 2021): Monolithic and iterative discretizations of linear poroelasticity (together with P. Henning and R. Altmann)
  • Felix Black, Technische Universität Berlin
    Master thesis (Jan. 2019): Model order reduction for transport phenomena (together with V. Mehrmann und P. Schulze)
  • Ines Ahrens, Technische Universität Berlin
    Master thesis (Sept. 2018): A Structural Approach for Delay Differential-Algebraic Equations (together with V. Mehrmann)
  • Viola Paschke, Technische Universität Berlin
    Master thesis (July 2016): Delayed Multibody Systems – Analysis and Numerical Solution (together with V. Mehrmann)

Scientific assistants, research projects, and interns:

  • Zubair Asif, University of Stuttgart, scientific assistant (since Nov. 2021)
  • Lisa Meisinger, University of Stuttgart, research project (since Oct. 2021)
  • Ahsan Ayaz, University of Stuttgart, scientific assistant (since June 2021)
  • Elliot Fosong, University of Cambridge, DAAD RISE internship (June-Sept. 2018)
  • Oumayma Bentamer, ENSEEIHT Toulouse, internship (Juni - Sept. 2017)
  • Yuliya Semibratova, University of Illinois at Urbana-Champaign, DAAD RISE internship (May - Aug. 2016)
  • Ines Ahrens, Technische Universität Berlin, scientific assistant (Apr. 2016 - Sept. 2018)
  • Viola Paschke, Technische Universität Berlin, scientific assistant (Feb. 2015 - Apr. 2016)

University of Stuttgart (independent teaching)

  • Seminar: Control theory (summer term 2022)
  • Seminar: Novel methods in simulation science (summer term 2022)
  • Seminar: Advanved topics in simulation science (winter term 2021/22)

Technische Universität Berlin

  • Assistent Lineare Algebra I für Mathematiker (Sommersemester 2020)
  • Assistent Analysis II für Mathematiker (Sommersemester 2019)
  • Assistent Analysis I für Mathematiker (Wintersemester 2018/2019)
  • Assistent Analysis II für Ingenieure (Early Bird, Sommersemester 2018)
  • Assistent Lineare Algebra II für Mathematiker (Wintersemester 2017/18)
  • Assistent Lineare Algebra II für Mathematiker (Sommersemester 2017)
  • Assistent Lineare Algebra I+II für Mathematiker (Wintersemester 2016/17)
  • Tutor Analysis I für Ingenieure (Wintersemester 2015)
  • Organisator Absolventen-Seminar NumerischeMathematik (Februar 2015 - Juli 2018)

Karlsruhe Institute for Technology

  • Tutor NumerischeMathematik II (Sommersemester 2012)
  • Tutor NumerischeMathematik I (Wintersemester 2011/12)
  • Tutor VorkursMathematik (Wintersemester 2011/12)
  • Tutor Einstieg in die Informatik und algorithmischeMathematik mit C++ (Sommersemester 2011)
  • Tutor Einstieg in die Informatik und algorithmische Mathematik mit Java (Wintersemester 2010/11)
  • Tutor Vorkurs Mathematik (Wintersemester 2010/11)
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