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We study in detail the role of covariant Lyapunov vectors and their respective angles for detecting transitions between metastable states in dynamical systems, as recently discussed in several atmospheric science applications. The…

Dynamical Systems · Mathematics 2023-02-15 Akim Viennet , Nikki Vercauteren , Maximilian Engel , Davide Faranda

In this paper we consider and generalize a model, recently proposed and analytically investigated in its quasi-stationary approximation by the authors, for visco-elasticity with large deformations and conditional compatibility, where the…

Analysis of PDEs · Mathematics 2024-03-14 Abramo Agosti , Michel Fremond

Stochastic differential equations (SDEs) are popular tools to analyse time series data in many areas, such as mathematical finance, physics, and biology. They provide a mechanistic description of the phenomeon of interest, and their…

Methodology · Statistics 2021-02-01 Théo Michelot , Richard Glennie , Catriona Harris , Len Thomas

We propose a new sensitivity analysis methodology for complex stochastic dynamics based on the Relative Entropy Rate. The method becomes computationally feasible at the stationary regime of the process and involves the calculation of…

Mathematical Physics · Physics 2013-04-16 Yannis Pantazis , Markos A. Katsoulakis

We study thermodynamical formalism of a discrete nonautonomous dynamical system determined by a sequence of continuous self-maps of a compact metric space. Using the methods of Convex Analysis we get variational principles for pressure…

Dynamical Systems · Mathematics 2026-03-10 Andrzej Biś

Whether deterministic or stochastic, models can be viewed as functions designed to approximate a specific quantity of interest. We introduce Minimal Empirical Variance Aggregation (MEVA), a data-driven framework that integrates predictions…

Machine Learning · Computer Science 2025-03-04 Théo Bourdais , Houman Owhadi

We address the issue of designing robust stabilization terms for the nonconforming virtual element method. To this end, we transfer the problem of defining the stabilizing bilinear form from the elemental nonconforming virtual element…

Numerical Analysis · Mathematics 2021-03-08 Silvia Bertoluzza , Gianmarco Manzini , Micol Pennacchio , Daniele Prada

Necessary and sufficient conditions for convexity and strong convexity, respectively, of sublevel sets that are defined by finitely many real-valued $C^{1,1}$-maps are presented. A novel characterization of strongly convex sets in terms of…

Optimization and Control · Mathematics 2017-01-03 Alexander Weber , Gunther Reissig

Background: In medical imaging, images are usually treated as deterministic, while their uncertainties are largely underexplored. Purpose: This work aims at using deep learning to efficiently estimate posterior distributions of imaging…

Image and Video Processing · Electrical Eng. & Systems 2023-03-20 Xiaofeng Liu , Thibault Marin , Tiss Amal , Jonghye Woo , Georges El Fakhri , Jinsong Ouyang

PieceWise Affine (PWA) approximations for nonlinear functions have been extensively used for tractable, computationally efficient control of nonlinear systems. However, reaching a desired approximation accuracy without prior information…

Systems and Control · Electrical Eng. & Systems 2025-11-04 Leila Gharavi , Bart De Schutter , Simone Baldi

Variational Autoencoders (VAEs) are well-established as a principled approach to probabilistic unsupervised learning with neural networks. Typically, an encoder network defines the parameters of a Gaussian distributed latent space from…

Machine Learning · Computer Science 2025-05-16 Alan Jeffares , Liyuan Liu

We propose an extension of the classical variational theory of evolution equations that accounts for dynamics also in possibly non-reflexive and non-separable spaces. The pivoting point is to establish a novel variational structure, based…

Analysis of PDEs · Mathematics 2021-09-17 Alexander Menovschikov , Anastasia Molchanova , Luca Scarpa

This paper presents a shape-theoretic framework for dynamical analysis of nonlinear dynamical systems which appear frequently in several video-based inference tasks. Traditional approaches to dynamical modeling have included linear and…

Computer Vision and Pattern Recognition · Computer Science 2016-11-17 Vinay Venkataraman , Pavan Turaga

The study gives a brief overview of existing modifications of the method of functional separation of variables for nonlinear PDEs. It proposes a more general approach to the construction of exact solutions to nonlinear equations of applied…

Mathematical Physics · Physics 2020-01-07 Andrei D. Polyanin

Envelope methods offer targeted dimension reduction for various models. The overarching goal is to improve efficiency in multivariate parameter estimation by projecting the data onto a lower-dimensional subspace known as the envelope.…

Methodology · Statistics 2022-07-13 Xin Zhang , Kai Deng , Qing Mai

This study shows that typical pendulum dynamics is far from the simple equation of motion presented in textbooks. A reasonably complete damping model must use nonlinear terms in addition to the common linear viscous expression. In some…

Classical Physics · Physics 2007-05-23 Randall D. Peters

Disentangled representation learning aims to learn low-dimensional representations where each dimension corresponds to an underlying generative factor. While the Variational Auto-Encoder (VAE) is widely used for this purpose, most existing…

Machine Learning · Computer Science 2024-12-31 Di Fan , Yannian Kou , Chuanhou Gao

A simple reweighting scheme is proposed for Monte Carlo simulations of interacting particle systems, permitting one to study various parameter values in a single study, and improving efficiency by an order of magnitude. Unlike earlier…

Statistical Mechanics · Physics 2009-10-31 Ronald Dickman

A shortcoming of existing reachability approaches for nonlinear systems is the poor scalability with the number of continuous state variables. To mitigate this problem we present a simulation-based approach where we first sample a number of…

Systems and Control · Computer Science 2017-09-21 Murat Arcak , John Maidens

The variational cluster approximation (VCA) proposed by M. Potthoff {\it et al.} [Phys. Rev. Lett. {\bf 91}, 206402 (2003)] is extended to electron or spin systems with nonlocal interactions. By introducing more than one source field in the…

Strongly Correlated Electrons · Physics 2016-08-31 Ning-Hua Tong