Research Group of Prof. Dr. Ira Neitzel

Address:
Institut für Numerische Simulation
Friedrich-Hirzebruch-Allee 7
53115 Bonn
Phone: +49 228 73-69837
Office: FHA7 3.034
E-Mail: ed tod nnob-inu tod sni ta leztiena tod b@foo tod de

Teaching

Summer semester 2026

Winter semester 2025/26

See teaching activities of the whole group.

Completed Research Projects

Optimizing Fracture Propagation Using a Phase-Field Approach

Project SPP 1962, DFG priority program 1962.

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Optimizing Fracture Propagation Using a Phase-Field Approach, Part II

Project SPP 1962 Phase 2, DFG priority program 1962, Phase II.

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Sparse controls in optimization of quasilinear partial differential equations

Project C10, DFG SFB 1060.

Homepage.

See all projects of the group.

Publications

Journal Papers

  1. Analysis of four-dimensional variational data assimilation problems in low regularity spaces. P. Castro, J. C. de los Reyes, and I. Neitzel. to appear in ESAIM: COCV, 2026. BibTeX
  2. Optimal control of quasilinear parabolic pdes with gradient terms and pointwise constraints on the gradient of the state. L. Bonifacius, F. Hoppe, H. Meinlschmidt, and I. Neitzel. Mathematical Control and Related Fields, 15(4):1284–1319, 2025. BibTeX DOI
  3. Local quadratic convergence of the SQP method for an optimal control problem governed by a regularized fracture propagation model. A. Hehl and I. Neitzel. ESAIM: COCV, 2024. BibTeX DOI
  4. Global-in-time solutions and hölder continuity for quasilinear parabolic pdes with mixed boundary conditions in the bessel dual scale. F. Hoppe, H. Meinlschmidt, and I. Neitzel. Evolution Equations and Control Theory, 13(5):1250–1286, 2024. Preprint version available on arXiv. BibTeX DOI
  5. Second Order Optimality Conditions for an Optimal Control Problem Governed by a Regularized Phase-Field Fracture Propagation Model. A. Hehl and I. Neitzel. Optimization, 2022. BibTeX DOI
  6. Optimal Control of Quasilinear Parabolic PDEs with State-Constraints. F. Hoppe and I. Neitzel. SIAM J. Control Optim., 60(1):330–354, 2022. BibTeX PDF DOI
  7. Purely time-dependent optimal control of quasilinear parabolic PDEs with sparsity enforcing penalization. F. Hoppe and I. Neitzel. ESAIM: COCV, 2022. also available as INS Preprint No. 2201. BibTeX PDF DOI
  8. Multigoal-oriented optimal control problems with nonlinear pde constraints. B. Endthmayer, U. Langer, I. Neitzel, T. Wick, and W. Wollner. Comput. Math. Appl., pages 3001–3026, 2020. Preprint available, SPP1962-108. BibTeX DOI
  9. Finite element error estimates for elliptic optimal control by bv functions. D. Hafemeyer, F. Mannel, I. Neitzel, and B. Vexler. Mathematical Control & Related Fields, 10(2):333–363, 2020. Preprint version available arXiv:1902.05893. BibTeX DOI
  10. Convergence of the SQP method for quasilinear parabolic optimal control problems. F. Hoppe and I. Neitzel. Optim. Eng., 2020. BibTeX PDF DOI
  11. A Lagrange multiplier method for semilinear elliptic state constrained optimal control problems. V. Karl, I. Neitzel, and D. Wachsmuth. Comput. Optim. Appl., pages 831–869, 2020. preprint available SPP1962-087. BibTeX DOI
  12. First-order conditions for the optimal control of the obstacle problem with state constraints. I. Neitzel and G. Wachsmuth. PAFA, 2020. also available as arXive Preprint arXiv:2012.15324. BibTeX
  13. A sparse control approach to optimal sensor placement in pde-constrained parameter estimation problems. I. Neitzel, K. Pieper, B. Vexler, and D. Walter. Numer. Math., 143:943–984, 2019. also available as preprint IGDK-2018-07. BibTeX DOI
  14. An optimal control problem governed by a regularized phase field fracture propagation model. Part II the regularization limit. I. Neitzel, T. Wick, and W. Wollner. SIAM J. Control Optim., 57(3):1672–1690, 2019. also available as SPP 1962 Preprint SPP1962-91. BibTeX DOI
  15. Second order optimality conditions for optimal control of quasilinear parabolic pdes. L. Bonifacius and I. Neitzel. Mathematical Control and Related Fields, 8(1):1–34, 2018. Preprint version available as INS Preprint No. 1705. BibTeX PDF DOI
  16. A priori error estimates for state constrained semilinear parabolic optimal control problems. F. Ludovici, I. Neitzel, and W. Wollner. J. Optim. Theory Appl., 178(2):317–348, 2018. also available as INS Preprint No. 1605. BibTeX PDF DOI
  17. An optimal control problem governed by a regularized phase field fracture propagation model. I. Neitzel, T. Wick, and W. Wollner. SIAM J. Control Optim., 55(4):2271–2288, 2017. also available as IGDK 1754 Preprint 2015-12. BibTeX DOI
  18. A priori l2l^2-discretization error estimates for the state in elliptic optimization problems with pointwise inequality state constraints. I. Neitzel and W. Wollner. Numer. Math., 2017. also available as INS Preprint No. 1606. BibTeX PDF DOI
  19. Dirichlet control of elliptic state constrained problems. M. Mateos and I. Neitzel. Comput. Optim. Appl., 2015. BibTeX DOI
  20. An adaptive numerical method for semi-infinite elliptic control problems based on error estimates. P. Merino, I. Neitzel, and F. Tröltzsch. Optim. Methods Softw., 30(3):492–515, 2015. BibTeX DOI
  21. Finite element discretization of state-constrained elliptic optimal control problems with semilinear state equation. I. Neitzel, J. Pfefferer, and A. Rösch. SIAM J. Control Optim., 53(2):874–904, 2015. BibTeX DOI
  22. Regularization for semilinear elliptic optimal control problems with pointwise state and control constraints. K. Krumbiegel, I. Neitzel, and A. Rösch. Comput. Optim. Appl., 52(1):181–207, 2012. BibTeX DOI
  23. A priori error estimates for space-time finite element discretization of semilinear parabolic optimal control problems. I. Neitzel and B. Vexler. Numer. Math., 120(2):345–386, 2012. BibTeX DOI
  24. On linear-quadratic elliptic control problems of semi-infinite type. P. Merino, I. Neitzel, and F. Tröltzsch. Appl. Anal., 90(6):1047–1074, 2011. BibTeX DOI
  25. A smooth regularization of the projection formula for constrained parabolic optimal control problems. I. Neitzel, U. Prüfert, and T. Slawig. Numer. Funct. Anal. Optim., 32(12):1283–1315, 2011. BibTeX DOI
  26. Sufficient optimality conditions for the Moreau-Yosida-type regularization concept applied to semilinear elliptic optimal control problems with pointwise state constraints. K. Krumbiegel, I. Neitzel, and A. Rösch. Ann. Acad. Rom. Sci. Ser. Math. Appl., 2(2):222–246, 2010. BibTeX
  27. Error estimates for the finite element discretization of semi-infinite elliptic optimal control problems. P. Merino, I. Neitzel, and F. Tröltzsch. Discuss. Math. Differ. Incl. Control Optim., 30(2):221–236, 2010. BibTeX DOI
  28. Strategies for time-dependent PDE control with inequality constraints using an integrated modeling and simulation environment. I. Neitzel, U. Prüfert, and T. Slawig. Numer. Algorithms, 50(3):241–269, 2009. BibTeX DOI
  29. On regularization methods for the numerical solution of parabolic control problems with pointwise state constraints. I. Neitzel and F. Tröltzsch. ESAIM Control Optim. Calc. Var., 15(2):426–453, 2009. BibTeX DOI
  30. On convergence of regularization methods for nonlinear parabolic optimal control problems with control and state constraints. I. Neitzel and F. Tröltzsch. Control Cybernet., 37(4):1013–1043, 2008. BibTeX

Proceedings, Series- and Book Contributions, Technical Reporst

  1. A-posteriori error estimation of discrete pod models for pde-constrained optimal control. M. Gubisch, I. Neitzel, and S. Volkwein. In Model reduction and approximation: theory and algorithms, volume of Computational Science and Engineering, pages. SIAM. BibTeX PDF
  2. Coefficient control of variational inequalities. A. Hehl, D. Khimin, I. Neitzel, N. Simon, T. Wick, and W. Wollner. In to appear. 2023. BibTeX
  3. A note on source term representation for control-and-state-constrained parabolic control problems with purely time-dependent control. I. Neitzel. Technical Report, Institute for Numerical Simulation, Bonn University, 2022. Available as INS Preprint No. 2206. BibTeX PDF
  4. Optimizing fracture propagation using a phase-field approach. A. Hehl, M. Mohammadi, I. Neitzel, and W. Wollner. In to appear. 2020. BibTeX
  5. Mesh adaptivity and error estimates applied to a regularized p-laplacian constrained optimal control problem for multiple quantities of interest. B. Endtmayer, Langer, Ulrich, I. Neitzel, T. W. Wick, and W. Wollner. PAMM, 2019. BibTeX DOI
  6. A priori error estimates for nonstationary optimal control problems with gradient constraints. F. Ludovici, I. Neitzel, and W. Wollner. PAMM, 15(1):611–612, 2015. BibTeX DOI
  7. Numerical analysis of state-constrained optimal control problems for PDEs. I. Neitzel and F. Tröltzsch. In Constrained optimization and optimal control for partial differential equations, volume 160 of Internat. Ser. Numer. Math., pages 467–482. Birkhäuser/Springer Basel AG, Basel, 2012. BibTeX DOI
  8. Optimal pde control using comsol multiphysics. I. Neitzel, U. Prüfert, and T. Slawig. Proceedings CD of the 2008 European COMSOL Conference, 2008. BibTeX
  9. Solving time-dependent optimal control problems in comsol multiphysics. I. Neitzel, U. Prüfert, and T. Slawig. Proceedings CD of the 2008 European COMSOL Conference, 2008. BibTeX