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We consider the Calder\'on problem with partial data in certain admissible geometries, that is, on compact Riemannian manifolds with boundary which are conformally embedded in a product of the Euclidean line and a simple manifold. We show…

Analysis of PDEs · Mathematics 2016-02-16 Casey Rodriguez

We propose, analyze, and test a novel continuous data assimilation two-phase flow algorithm for reservoir simulation. We show that the solutions of the algorithm, constructed using coarse mesh observations, converge at an exponential rate…

Numerical Analysis · Mathematics 2022-06-22 Yat Tin Chow , Wing Tat Leung , Ali Pakzad

In this article we develop algorithms for data assimilation based upon a computational time dependent stable/unstable splitting. Our particular method is based upon shadowing refinement and synchronization techniques and is motivated by…

Dynamical Systems · Mathematics 2017-07-31 Bart de Leeuw , Svetlana Dubinkina , Jason Frank , Andrew Steyer , Xuemin Tu , Erik Van Vleck

In this paper, we introduce a new adaptive data analysis method to study trend and instantaneous frequency of nonlinear and non-stationary data. This method is inspired by the Empirical Mode Decomposition method (EMD) and the recently…

Numerical Analysis · Mathematics 2012-02-28 Thomas Y. hou , Zuoqiang Shi

We consider time discretization methods for abstract parabolic problems with inhomogeneous linear constraints. Prototype examples that fit into the general framework are the heat equation with inhomogeneous (time dependent) Dirichlet…

Numerical Analysis · Mathematics 2018-06-14 Igor Voulis , Arnold Reusken

Data assimilation (DA) combines partial observations with dynamical models to improve state estimation. Filter-based DA uses only past and present data and is the prerequisite for real-time forecasts. Smoother-based DA exploits both past…

Systems and Control · Electrical Eng. & Systems 2026-01-21 Marios Andreou , Nan Chen , Yingda Li

We consider a stochastic heat equation with nonlinear finite-rank space-coloured multiplicative noise that admits a unique nonnegative solution when given nonnegative initial data. Inspired by existing results for fully discrete finite…

Numerical Analysis · Mathematics 2026-04-30 Owen Hearder , Claude Le Bris , Ana Djurdjevac

We present a nonvariational setting for the Neumann problem for the Poisson equation for solutions that are H\"{o}lder continuous and that may have infinite Dirichlet integral. We introduce a distributional normal derivative on the boundary…

Analysis of PDEs · Mathematics 2024-05-06 M. Lanza de Cristoforis

We use a diffuse interface method for solving Poisson's equation with a Dirichlet condition on an embedded curved interface. The resulting diffuse interface problem is identified as a standard Dirichlet problem on approximating regular…

Numerical Analysis · Mathematics 2015-11-23 Matthias Schlottbom

In this paper we continue our work on adaptive timestep control for weakly non- stationary problems. The core of the method is a space-time splitting of adjoint error representations for target functionals due to S\"uli and Hartmann. The…

Numerical Analysis · Mathematics 2014-06-19 Christina Steiner , Siegfried Müller , Sebastian Noelle

We consider two steady-state heat conduction systems called, $S$ and $S_\alpha$, in a multidimensional bounded domain $D$ for the Poisson equation with source energy $g$. In one system, we impose mixed boundary conditions (temperature $b$…

Numerical Analysis · Mathematics 2026-03-13 Julieta Bollati , Mariela C. Olguin , Domingo A. Tarzia

This paper applies variational data assimilation to inundation problems governed by the shallow water equations with wetting and drying. The objective of the assimilation is to recover an unknown time-varying wave profile at an open ocean…

Fluid Dynamics · Physics 2017-06-07 S. W Funke , P. E Farrell , M. D. Piggott

This paper is concerned with the study of constrained statistical learning problems, the unconstrained version of which are at the core of virtually all of modern information processing. Accounting for constraints, however, is paramount to…

Machine Learning · Computer Science 2020-02-14 Luiz F. O. Chamon , Santiago Paternain , Miguel Calvo-Fullana , Alejandro Ribeiro

This paper studies a two-material optimal design problem for the time-averaged duality pairing between a (possibly time-dependent) heat source and the weak solution of an initial-boundary value problem for the heat equation with a…

Analysis of PDEs · Mathematics 2025-09-16 Kei Matsushima , Tomoyuki Oka

In this work, we investigate the estimation of the transient mold-slab heat flux in continuous casting molds given some thermocouples measurements in the mold plates. Mathematically, we can see this problem as the estimation of a Neumann…

Numerical Analysis · Mathematics 2022-10-06 Umberto Emil Morelli , Patricia Barral , Peregrina Quintela , Gianluigi Rozza , Giovanni Stabile

In this paper we prove optimal error estimates for {solutions with natural regularity} of the equations describing the unsteady motion of incompressible shear-thinning fluids. We consider a full space-time semi-implicit scheme for the…

Numerical Analysis · Mathematics 2020-11-26 Luigi C. Berselli , Michael Růžička

Variational inequalities are an important tool, which includes minimization, saddles, games, fixed-point problems. Modern large-scale and computationally expensive practical applications make distributed methods for solving these problems…

Optimization and Control · Mathematics 2023-03-01 Aleksandr Beznosikov , Alexander Gasnikov

The understanding of nonlinear, high dimensional flows, e.g, atmospheric and ocean flows, is critical to address the impacts of global climate change. Data Assimilation techniques combine physical models and observational data, often in a…

We present a novel framework for assimilating planar PIV experimental data using a variational approach to enhance the predictions of the Spalart-Allmaras RANS turbulence model. Our method applies three-dimensional constraints to the…

Fluid Dynamics · Physics 2026-01-27 Uttam Cadambi Padmanaban , Bharathram Ganapathisubramani , Sean Symon

A numerical method for approximating weak solutions of an aggregation equation with degenerate diffusion is introduced. The numerical method consists of a stabilized finite element method together with a mass lumping technique and an extra…