Search Results for author: Tim Mitchell

Found 6 papers, 1 papers with code

Optimization and Optimizers for Adversarial Robustness

no code implementations23 Mar 2023 Hengyue Liang, Buyun Liang, Le Peng, Ying Cui, Tim Mitchell, Ju Sun

Taking advantage of PWCF and other existing numerical algorithms, we further explore the distinct patterns in the solutions found for solving these optimization problems using various combinations of losses, perturbation models, and optimization algorithms.

Adversarial Robustness

NCVX: A General-Purpose Optimization Solver for Constrained Machine and Deep Learning

no code implementations3 Oct 2022 Buyun Liang, Tim Mitchell, Ju Sun

Imposing explicit constraints is relatively new but increasingly pressing in deep learning, stimulated by, e. g., trustworthy AI that performs robust optimization over complicated perturbation sets and scientific applications that need to respect physical laws and constraints.

Optimization for Robustness Evaluation beyond $\ell_p$ Metrics

no code implementations2 Oct 2022 Hengyue Liang, Buyun Liang, Ying Cui, Tim Mitchell, Ju Sun

Empirical evaluation of deep learning models against adversarial attacks entails solving nontrivial constrained optimization problems.

NCVX: A User-Friendly and Scalable Package for Nonconvex Optimization in Machine Learning

1 code implementation27 Nov 2021 Buyun Liang, Tim Mitchell, Ju Sun

GRANSO is among the first optimization solvers targeting general nonsmooth NCVX problems with nonsmooth constraints, but, as it is implemented in MATLAB and requires the user to provide analytical gradients, GRANSO is often not a convenient choice in machine learning (especially deep learning) applications.

BIG-bench Machine Learning

Optimization-based parametric model order reduction via $\mathcal{H}_2\otimes\mathcal{L}_2$ first-order necessary conditions

no code implementations4 Mar 2021 Manuela Hund, Tim Mitchell, Petar Mlinarić, Jens Saak

In this paper, we generalize existing frameworks for $\mathcal{H}_2\otimes\mathcal{L}_2$-optimal model order reduction to a broad class of parametric linear time-invariant systems.

Optimization and Control Numerical Analysis Systems and Control Systems and Control Numerical Analysis 15A24, 46N10, 65K05, 65Y20, 93A15, 93B40

Fast Interpolation-based Globality Certificates for Computing Kreiss Constants and the Distance to Uncontrollability

no code implementations2 Oct 2019 Tim Mitchell

Divide-and-conquer techniques have been proposed that reduce the work complexity to $\mathcal{O}(n^4)$ on average and $\mathcal{O}(n^5)$ in the worst case, but these variants are nevertheless still very expensive and can be numerically unreliable.

Optimization and Control Numerical Analysis Numerical Analysis

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