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We present a novel method for convex unconstrained optimization that, without any modifications, ensures: (i) accelerated convergence rate for smooth objectives, (ii) standard convergence rate in the general (non-smooth) setting, and (iii)…

Machine Learning · Computer Science 2018-09-11 Kfir Y. Levy , Alp Yurtsever , Volkan Cevher

In this paper a new primal-dual mixed finite element method is introduced, aimed to model multiscale problems with several geometric subregions in the domain of interest. In each of these regions porous media fluid flow takes place, but…

Numerical Analysis · Mathematics 2020-08-21 Fernando A Morales

We shall establish the convergence of an adaptive conforming finite element method for the reconstruction of the distributed flux in a diffusion system. The adaptive method is based on a posteriori error estimators for the distributed flux,…

Numerical Analysis · Mathematics 2013-09-10 Yifeng Xu , Jun Zou

Vertical equilibrium models have proven to be well suited for simulating fluid flow in subsurface porous media such as saline aquifers with caprocks. However, in most cases the dimensionally reduced model lacks the accuracy to capture the…

Fluid Dynamics · Physics 2024-05-29 Ivan Buntic , Martin Schneider , Bernd Flemisch , Rainer Helmig

The velocity, coupling term in the flow and transport problems, is important in the accurate numerical simulation or in the posteriori error analysis for adaptive mesh refinement. We consider Enhanced Velocity Mixed Finite Element Method…

Numerical Analysis · Mathematics 2024-12-20 Yerlan Amanbek , Gurpreet Singh , Mary F. Wheeler

One of the biggest challenges in Federated Learning (FL) is that client devices often have drastically different computation and communication resources for local updates. To this end, recent research efforts have focused on training…

Machine Learning · Computer Science 2022-02-10 Hanhan Zhou , Tian Lan , Guru Venkataramani , Wenbo Ding

Online convex optimization is a sequential prediction framework with the goal to track and adapt to the environment through evaluating proper convex loss functions. We study efficient particle filtering methods from the perspective of such…

Machine Learning · Computer Science 2018-07-23 Mahdi Azarafrooz

Online optimization has emerged as powerful tool in large scale optimization. In this paper, we introduce efficient online algorithms based on the alternating directions method (ADM). We introduce a new proof technique for ADM in the batch…

Machine Learning · Computer Science 2012-07-03 Huahua Wang , Arindam Banerjee

Based on previous work we extend a primal-dual semi-smooth Newton method for minimizing a general $L^1$-$L^2$-$TV$ functional over the space of functions of bounded variations by adaptivity in a finite element setting. For automatically…

Numerical Analysis · Mathematics 2025-02-19 Martin Alkämper , Stephan Hilb , Andreas Langer

In this paper, we consider a time-dependent discrete network model with highly varying connectivity. The approximation by time is performed using an implicit scheme. We propose the coarse scale approximation construction of network models…

Numerical Analysis · Mathematics 2024-09-02 Maria Vasilyeva

In recent years, deep neural networks have shown remarkable progress in dense disparity estimation from dynamic scenes in monocular structured light systems. However, their performance significantly drops when applied in unseen…

Computer Vision and Pattern Recognition · Computer Science 2023-10-16 Rukun Qiao , Hiroshi Kawasaki , Hongbin Zha

Real-world intelligence systems usually operate by combining offline learning and online adaptation with highly correlated and non-stationary system data or signals, which, however, has rarely been investigated theoretically in the…

Machine Learning · Computer Science 2025-12-02 Haizheng Li , Lei Guo

In this paper, we present a residual-driven multiscale method for simulating Darcy flow in perforated domains, where complex geometries and highly heterogeneous permeability make direct simulations computationally expensive. To address…

Numerical Analysis · Mathematics 2026-03-11 Wei Xie , Shubin Fu , Yin Yang , Yunqing Huang

In this contribution we consider localized, robust and efficient a-posteriori error estimation of the localized reduced basis multi-scale (LRBMS) method for parametric elliptic problems with possibly heterogeneous diffusion coefficient. The…

Numerical Analysis · Mathematics 2019-10-30 Mario Ohlberger , Felix Schindler

In this paper, we propose a randomized generalized multiscale finite element method (Randomized GMsFEM) for flow problems with parameterized inputs and high-contrast heterogeneous media. The method employs a data-driven predictor to…

Numerical Analysis · Mathematics 2025-08-05 Wing Tat Leung , Qiuqi Li , Songwei Liu

We study value adaptation in offline-to-online reinforcement learning under general function approximation. Starting from an imperfect offline pretrained $Q$-function, the learner aims to adapt it to the target environment using only a…

Machine Learning · Computer Science 2026-04-16 Shangzhe Li , Weitong Zhang

In this paper, we present an Online Generalized Multiscale Finite Element Method(Online GMsFEM) for heat and mass transfer problem in heterogeneous media with artificial ground freezing pipes. The mathematical model of the process is based…

Numerical Analysis · Mathematics 2022-05-31 Denis Spiridonov , Sergei Stepanov , Vasil`ev Vasiliy

We present an adaptive methodology for the solution of (linear and) non-linear time dependent problems that is especially tailored for massively parallel computations. The basic concept is to solve for large blocks of space-time unknowns…

Computational Physics · Physics 2016-08-30 Robert Dyja , Baskar Ganapathysubramanian , Kristoffer G. van der Zee

In this paper, we consider the complex flows when all three regimes pre-Darcy, Darcy and post-Darcy may be present in different portions of a same domain. We unify all three flow regimes under mathematics formulation. We describe the flow…

Numerical Analysis · Mathematics 2021-06-24 John Cummings , Matthew Hamilton , Thinh Kieu

The flux-mortar mixed finite element method was recently developed for a general class of domain decomposition saddle point problems on non-matching grids. In this work we develop the method for Darcy flow using the multipoint flux…

Numerical Analysis · Mathematics 2023-01-18 Wietse M. Boon , Dennis Gläser , Rainer Helmig , Ivan Yotov