Tim Mitchell

Publications

• An Experimental Comparison of Methods for Computing the Numerical Radius
  Tim Mitchell and Michael L. Overton
  Results Appl. Math., 21:100434, 2024.
  Preprint available on arXiv.
• Optimization and optimizers for adversial robustness
  Hengyue Liang, Buyun Liang, Le Peng, Ying Cui, Tim Mitchell, and Ju Sun
  Preprint available on arXiv.
• Optimization for robustness evaluation beyond l_p metrics
  Hengyue Liang, Buyun Liang, Ying Cui, Tim Mitchell, and Ju Sun
  ICASSP 2023 - 2023 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) , Rhodes Island, 2023, pp. 1-5.
  Preprint available on arXiv.
• Implications of solution patterns on adversial robustness
  Hengyue Liang, Buyun Liang, Ying Cui, Tim Mitchell, and Ju Sun
  2023 IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), Vancouver, 2023, pp. 2393-2400.
  
• NCVX: A User-Friendly and Scalable Package for Nonconvex Optimization in Machine Learning
  Buyun Liang, Tim Mitchell, and Ju Sun
  Submitted, 2022.
  Preprint available on arXiv.
• Root-max Problems, Hybrid Expansion-Contraction, and Quadratically Convergent Optimization of Passive Systems
  Tim Mitchell and Paul Van Dooren
  SIAM J. Matrix Anal. Appl., 44(2):753-780, 2023
  Preprint available on arXiv.
• On Properties of Univariate Max Functions at Local Maximizers
  Tim Mitchell and Michael L. Overton
  Optim. Lett., 16:2527-2541, 2022.
  Preprint available on arXiv.
• Fast optimization of viscosities for frequency-weighted damping of second-order systems
  Nevena Jakovčević Stor, Tim Mitchell, Zoran Tomljanović, and Matea Ugrica
  Z. Angew. Math. Mech., 103(5):e202100127, 2023
  Preprint available on arXiv.
• Optimization-based parametric model order reduction via H₂⊗L₂ first-order necessary conditions
  Manuela Hund, Tim Mitchell, Petar Mlinarić, and Jens Saak
  SIAM J. Sci. Comput., 44(3):A1554-A1578, 2022.
  Preprint available on arXiv.
• Convergence rate analysis and improved iterations for numerical radius computation
  Tim Mitchell
  SIAM J. Sci. Comput., 45(2):A753-A780, 2023.
  Preprint available on arXiv.
• Fast Computation of Sep-lambda via Interpolation-based Globality Certificates
  Tim Mitchell
  Electron. Trans. Numer. Anal., 48:402-431, 2023.
  Preprint available on arXiv.
• Fast Interpolation-based Globality Certificates for Computing Kreiss Constants and the Distance to Uncontrollability
  Tim Mitchell
  SIAM J. Matrix Anal. Appl., 42(2):578-607, 2021
  Preprint available on arXiv.
• Computing the Kreiss Constant of a Matrix
  Tim Mitchell
  SIAM J. Matrix Anal. Appl., 41(4):1944-1975, 2020
  Preprint available on arXiv.
• A Comparison of Nonsmooth, Nonconvex, Constrained Optimization Solvers for the Design of Time-Delay Compensators
  Vyacheslav Kungurtsev, Tim Mitchell, and Tomas Vyhlídal
  Submitted, 2018.
  Preprints available on arXiv and Optimization Online.
• Low-Order Control Design using a Reduced-Order Model with a Stability Constraint on the Full-Order Model
  Peter Benner, Tim Mitchell, and Michael L. Overton
  IEEE 57th Annual Conference on Decision and Control (CDC), Miami, 2018, pp. 3000-3005.
  Preprint available on arXiv.
• Extended and improved criss-cross algorithms for computing the spectral value set abscissa and radius
  Peter Benner and Tim Mitchell
  SIAM J. Matrix Anal. Appl., 40(4):1325-1352, 2019.
  Preprint available on arXiv.
• Faster and more accurate computation of the H_∞ norm via optimization
  Peter Benner and Tim Mitchell
  SIAM J. Sci. Comput., 40(5):A3609–A3635, 2018.
  Preprint available on arXiv.
• On Reduced Input-Output Dynamic Mode Decomposition
  Peter Benner, Christian Himpe, and Tim Mitchell
  Advances in Computational Mathematics, 44(6):1751–1768, 2018.
  Preprint available on arXiv.
• Approximating the Real Structured Stability Radius with Frobenius Norm Bounded Perturbations
  Nicola Guglielmi, Mert Gürbüzbalaban, Tim Mitchell, and Michael L. Overton
  SIAM J. Matrix Anal. Appl., 38(4):1323–1353, 2017.
  Preprint available on arXiv.
• A BFGS-SQP Method for Nonsmooth, Nonconvex, Constrained Optimization and its Evaluation using Relative Minimization Profiles
  Frank E. Curtis, Tim Mitchell, and Michael L. Overton
  Optimization Methods and Software, 32(1):148–181, 2017.
• Hybrid Expansion-Contraction: a Robust Scaleable Method for Approximating the H_∞ Norm
  Tim Mitchell and Michael L. Overton
  IMA J. Numer. Anal., 36(3):985–1014, 2016.
• Fixed low-order controller design and H_∞ optimization for large-scale dynamical systems
  Tim Mitchell and Michael L. Overton
  IFAC-PapersOnLine: Proceedings of 8th IFAC Symposium on Robust Control Design (ROCOND 2015), Bratislava, 48(14):25-30, 2015.

PhD Thesis

• Robust and efficient methods for approximation and optimization of stability measures
  Tim Mitchell
  PhD Thesis, Department of Computer Science, New York University, September 2014