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In this work we present the convergence of a positivity preserving semi-discrete finite volume scheme for a coupled system of two non-local partial differential equations with cross-diffusion. The key to proving the convergence result is to…

Numerical Analysis · Mathematics 2020-04-13 José A. Carrillo , Francis Filbet , Markus Schmidtchen

We model two time and space scales discrete observations by using a unique continuous diffusion process with time dependent coefficient. We define new parameters for the large scale model as functions of the small scale distribution…

Methodology · Statistics 2009-09-09 V. Calian , G. Stefansson , L. P. Folkow , A. S. Blix

We introduce a novel discretization technique for both elliptic and parabolic fractional diffusion problems based on double exponential quadrature formulas and the Riesz-Dunford functional calculus. Compared to related schemes, the new…

Numerical Analysis · Mathematics 2020-12-11 Alexander Rieder

Conditional diffusion probabilistic models can model the distribution of natural images and can generate diverse and realistic samples based on given conditions. However, oftentimes their results can be unrealistic with observable color…

Computer Vision and Pattern Recognition · Computer Science 2022-12-15 Kangfu Mei , Nithin Gopalakrishnan Nair , Vishal M. Patel

Motivated by problems in contact mechanics, we propose a duality approach for computing approximations and associated a posteriori error bounds to solutions of variational inequalities of the first kind. The proposed approach improves upon…

Numerical Analysis · Mathematics 2014-10-09 Zhenying Zhang , Eduard Bader , Karen Veroy

We study asymptotic properties of conditional least squares estimators for the drift parameters of two-factor affine diffusions based on continuous time observations. We distinguish three cases: subcritical, critical and supercritical. For…

Probability · Mathematics 2017-07-27 Beáta Bolyog , Gyula Pap

We present a weighted estimator of the covariance and correlation in bipartite complex systems with a double layer of heterogeneity. The advantage provided by the weighted estimators lies in the fact that the unweighted sample covariance…

Data Analysis, Statistics and Probability · Physics 2016-12-22 Elena Puccio , Jyrki Piilo , Michele Tumminello

For the concrete model of Brownian particles dynamics in non-uniform environment, the time interval estimation is constructed, on which phenomenological Fick laws for diffusion phenomenon description can be used. The knowledge of these…

Probability · Mathematics 2012-12-11 V. A Doobko

Data scarcity drives the need for more sample-efficient large language models. In this work, we use the double descent phenomenon to holistically compare the sample efficiency of discrete diffusion and autoregressive models. We show that…

Machine Learning · Computer Science 2025-09-30 Ahmad Fraij , Sam Dauncey

Duality relations between continuous-state and discrete-state stochastic processes with continuous-time have already been studied and used in various research fields. We propose extended duality relations, which enable us to derive…

Statistical Mechanics · Physics 2013-09-04 Jun Ohkubo

We establish certain maximum principles for a class of strongly coupled elliptic (or cross diffusion) systems of $m\ge2$ equations. The reaction parts can be non cooperative. These new results will be crucial in obtaining coexistence and…

Analysis of PDEs · Mathematics 2023-04-18 Dung Le

In this work we focus our attention on distributed optimization problems in the context where the communication time between the server and the workers is non-negligible. We obtain novel methods supporting bidirectional compression (both…

Optimization and Control · Mathematics 2023-05-23 Kaja Gruntkowska , Alexander Tyurin , Peter Richtárik

A new time discretization scheme for the numerical simulation of two-phase flow governed by a thermodynamically consistent diffuse interface model is presented. The scheme is consistent in the sense that it allows for a discrete in time…

Analysis of PDEs · Mathematics 2014-02-27 Harald Garcke , Michael Hinze , Christian Kahle

Explicit examples of scalar enhanced diffusion due to resonances between different transport mechanisms are presented. Their signature is provided by the sharp and narrow peaks observed in the effective diffusivity coefficients and, in the…

chao-dyn · Physics 2009-10-31 P. Castiglione , A. Crisanti , A. Mazzino , M. Vergassola , A. Vulpiani

In this article, we describe a simple class of models of absorbed diffusion processes with parameter, whose conditional law exhibits a transcritical bifurcation. Our proofs are based on the description of the set of quasi-stationary…

Probability · Mathematics 2021-12-13 Michel Benaïm , Nicolas Champagnat , William Oçafrain , Denis Villemonais

A model for cross-over designs with repeated measures within each period was developed. It is obtained using an extension of generalized estimating equations that includes a parametric component to model treatment effects and a…

Methodology · Statistics 2023-03-21 N. A. Cruz , O. O. Melo , C. A. Martinez

Cross-diffusion systems arise as hydrodynamic limits of lattice multi-species interacting particle models. The objective of this work is to provide a numerical scheme for the simulation of the cross-diffusion system identified in [J.…

Numerical Analysis · Mathematics 2023-09-06 Jad Dabaghi , Virginie Ehrlacher , Christoph Strössner

The (conditional or unconditional) distribution of the continuous scan statistic in a one-dimensional Poisson process may be approximated by that of a discrete analogue via time discretization (to be referred to as the discrete…

Probability · Mathematics 2016-02-09 Yi-Ching Yao , Daniel Wei-Chung Miao , Xenos Chang-Shuo Lin

Unmeasured confounding and selection bias are often of concern in observational studies and may invalidate a causal analysis if not appropriately accounted for. Under outcome-dependent sampling, a latent factor that has causal effects on…

Methodology · Statistics 2022-08-03 Kendrick Qijun Li , Xu Shi , Wang Miao , Eric Tchetgen Tchetgen

We prove optimal estimates for the decay in time of solutions to a rather general class of non-local in time subdiffusion equations in $\mathbb{R}^d$. An important special case is the time-fractional diffusion equation, which has seen much…

Analysis of PDEs · Mathematics 2014-03-10 Jukka Kemppainen , Juhana Siljander , Vicente Vergara , Rico Zacher