Learning dynamical systems from data: a simple cross-validation perspective, part I: parametric kernel flows

B Hamzi, H Owhadi - Physica D: Nonlinear Phenomena, 2021 - Elsevier
Regressing the vector field of a dynamical system from a finite number of observed states is
a natural way to learn surrogate models for such systems. We present variants of cross …

One-shot learning of stochastic differential equations with data adapted kernels

M Darcy, B Hamzi, G Livieri, H Owhadi… - Physica D: Nonlinear …, 2023 - Elsevier
We consider the problem of learning Stochastic Differential Equations of the form d X t= f (X
t) d t+ σ (X t) d W t from one sample trajectory. This problem is more challenging than …

[HTML][HTML] Learning dynamical systems from data: A simple cross-validation perspective, part iv: case with partial observations

B Hamzi, H Owhadi, Y Kevrekidis - Physica D: Nonlinear Phenomena, 2023 - Elsevier
A simple and interpretable way to learn a dynamical system from data is to interpolate its
governing equations with a kernel. In particular, this strategy is highly efficient (both in terms …

Model reduction for nonlinear systems by balanced truncation of state and gradient covariance

SE Otto, A Padovan, CW Rowley - SIAM Journal on Scientific Computing, 2023 - SIAM
Data-driven reduced-order models often fail to make accurate forecasts of high-dimensional
nonlinear dynamical systems that are sensitive along coordinates with low-variance …

Approximation of Lyapunov functions from noisy data

P Giesl, B Hamzi, M Rasmussen… - arXiv preprint arXiv …, 2016 - arxiv.org
Methods have previously been developed for the approximation of Lyapunov functions
using radial basis functions. However these methods assume that the evolution equations …

Kernel methods for center manifold approximation and a weak data-based version of the center manifold theorem

B Haasdonk, B Hamzi, G Santin, D Wittwar - Physica D: Nonlinear …, 2021 - Elsevier
For dynamical systems with a non hyperbolic equilibrium, it is possible to significantly
simplify the study of stability by means of the center manifold theory. This theory allows to …

Kernel methods for the approximation of nonlinear systems

J Bouvrie, B Hamzi - SIAM Journal on Control and Optimization, 2017 - SIAM
We introduce a data-driven model approximation method for nonlinear control systems,
drawing on recent progress in machine learning and statistical-dimensionality reduction …

Kernel sum of squares for data adapted kernel learning of dynamical systems from data: A global optimization approach

D Lengyel, P Parpas, B Hamzi, H Owhadi - arXiv preprint arXiv …, 2024 - arxiv.org
This paper examines the application of the Kernel Sum of Squares (KSOS) method for
enhancing kernel learning from data, particularly in the context of dynamical systems …

Dimensionality reduction of complex metastable systems via kernel embeddings of transition manifolds

A Bittracher, S Klus, B Hamzi, P Koltai… - Journal of Nonlinear …, 2021 - Springer
We present a novel kernel-based machine learning algorithm for identifying the low-
dimensional geometry of the effective dynamics of high-dimensional multiscale stochastic …

Gaussian processes simplify differential equations

J Lee, B Hamzi, Y Kevrekidis, H Owhadi - arXiv preprint arXiv:2410.03003, 2024 - arxiv.org
In this paper we use Gaussian processes (kernel methods) to learn mappings between
trajectories of distinct differential equations. Our goal is to simplify both the representation …