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The lattice Boltzmann method (LBM) is a numerical approach to tackle problems described by a Boltzmann type-equation, where time, space, and velocities are discretized to describe scattering and advection. Even though the LBM executes…

Computational Physics · Physics 2020-09-10 René Hammer , Verena Fritz , Natalia Bedoya-Martínez

An adaptive projection-based reduced-order model (ROM) formulation is presented for model-order reduction of problems featuring chaotic and convection-dominant physics. An efficient method is formulated to adapt the basis at every time-step…

Computational Physics · Physics 2023-08-09 Cheng Huang , Karthik Duraisamy

In this paper, a lattice Boltzmann (LB) model with double distribution functions is proposed for two-phase flow in porous media where one distribution function is used for pressure governed by the Poisson equation, and the other is applied…

Computational Physics · Physics 2018-08-24 Zhenhua Chai , Hong Liang , Rui Du , Baochang Shi

A multi-fidelity surrogate model for highly nonlinear multiscale problems is proposed. It is based on the introduction of two different surrogate models and an adaptive on-the-fly switching. The two concurrent surrogates are built…

Computational Physics · Physics 2019-05-03 Felix Fritzen , Mauricio Fernández , Fredrik Larsson

Score-based diffusion models currently constitute the state of the art in continuous generative modeling. These methods are typically formulated via overdamped or underdamped Ornstein--Uhlenbeck-type stochastic differential equations, in…

Machine Learning · Computer Science 2025-12-22 Herlock Rahimi

Agent-Based Models (ABMs) are powerful tools for studying emergent properties in complex systems. In ABMs, agent behaviors are governed by local interactions and stochastic rules. However, these rules are, in general, non-differentiable,…

Artificial Intelligence · Computer Science 2025-11-27 Francesco Cozzi , Marco Pangallo , Alan Perotti , André Panisson , Corrado Monti

In turbulent flows subject to strong background rotation, the advective mechanisms of turbulence are superseded by the propagation of inertial waves, as the effects of rotation become dominant. While this mechanism has been identified…

Fluid Dynamics · Physics 2020-02-19 J. A. Brons , P. J. Thomas , A. Potherat

Distortion Risk Measures (DRMs) capture risk preferences in decision-making and serve as general criteria for managing uncertainty. This paper proposes gradient descent algorithms for DRM optimization based on two dual representations: the…

Machine Learning · Computer Science 2025-10-07 Jinyang Jiang , Bernd Heidergott , Jiaqiao Hu , Yijie Peng

We expand on a previous study of fronts in finite particle number reaction-diffusion systems in the presence of a reaction rate gradient in the direction of the front motion. We study the system via reaction-diffusion equations, using the…

Statistical Mechanics · Physics 2009-11-11 Elisheva Cohen , David A. Kessler , Herbert Levine

The classical models for irreversible diffusion-influenced reactions can be derived by introducing absorbing boundary conditions to over-damped continuous Brownian motion (BM) theory. As there is a clear corresponding stochastic process,…

Statistical Mechanics · Physics 2016-10-13 Mauricio J. Del Razo , Hong Qian

We present a dual-resolution molecular dynamics (MD) simulation of liquid water employing a recently introduced Adaptive Resolution Scheme (AdResS). The spatially adaptive molecular resolution procedure allows for changing from a…

Soft Condensed Matter · Physics 2011-11-10 Silvina Matysiak , Cecilia Clementi , Matej Praprotnik , Kurt Kremer , Luigi Delle Site

The Stokes-Brinkman equations model fluid flow in highly heterogeneous porous media. In this paper, we consider the numerical solution of the Stokes-Brinkman equations with stochastic permeabilities, where the permeabilities in subdomains…

Numerical Analysis · Mathematics 2021-04-26 Kevin Williamson , Heyrim Cho , Bedřich Sousedík

A free boundary diffusive logistic model finds application in many different fields from biological invasion to wildfire propagation. However, many of these processes show a random nature and contain uncertainties in the parameters. In this…

Numerical Analysis · Mathematics 2025-01-17 M. -C. Casabán , R. Company , V. N. Egorova , L. Jódar

The problem of front propagation in flowing media is addressed for laminar velocity fields in two dimensions. Three representative cases are discussed: stationary cellular flow, stationary shear flow, and percolating flow. Production terms…

Chaotic Dynamics · Physics 2009-10-31 M. Abel , A. Celani , D. Vergni , A. Vulpiani

We study various combinations of active diffusion with branching, as an extension of standard reaction-diffusion processes. We concentrate on the selection of the asymptotic wavefront speed for thermal run-and-tumble and for thermal active…

Statistical Mechanics · Physics 2020-05-22 Thibaut Demaerel , Christian Maes

The reaction-diffusion master equation (RDME) is a model that allows for efficient on-lattice simulation of spatially resolved stochastic chemical kinetics. Compared to off-lattice hard-sphere simulations with Brownian Dynamics (BD) or…

Numerical Analysis · Mathematics 2017-09-06 Stefan Hellander , Andreas Hellander , Linda Petzold

Biochemical reactions can happen on different time scales and also the abundance of species in these reactions can be very different from each other. Classical approaches, such as deterministic or stochastic approach, fail to account for or…

Quantitative Methods · Quantitative Biology 2014-09-16 Arnab Ganguly , Derya Altintan , Heinz Koeppl

Many natural phenomena involve processes that happen simultaneously at different characteristic length- and timescales. Typically, the region where the process of interest happens is affected by fluctuations in its surroundings. Modeling…

Materials Science · Physics 2026-04-24 Hari Haran Sudhakar , Alessandra Serva , Rocio Semino

The reaction-diffusion master equation (RDME) is a lattice-based stochastic model for spatially resolved cellular processes. It is often interpreted as an approximation to spatially continuous reaction-diffusion models, which, in the limit…

Statistical Mechanics · Physics 2022-01-11 Alberto Montefusco , Christof Schütte , Stefanie Winkelmann

Anomalous diffusion, in particular subdiffusion, is frequently invoked as a mechanism of motion in dense biological media, and may have a significant impact on the kinetics of binding/unbinding events at the cellular level. In this work we…

Statistical Mechanics · Physics 2015-06-10 S. B. Yuste , E. Abad , K. Lindenberg