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We propose a simple route to evaluate the static structure, in terms of average coordination, of completely disordered solids with spherical constituents, from ca. 55% volume fraction up to random close packing, in the absence of structural…

Soft Condensed Matter · Physics 2009-05-08 Alessio Zaccone

A reliable and efficient computation of the entire single-particle spectrum of correlated molecules is an outstanding challenge in the field of quantum chemistry, with standard density functional theory approaches often giving an inadequate…

Chemical Physics · Physics 2021-10-08 Oliver J. Backhouse , Alejandro Santana-Bonilla , George H. Booth

We study a fluid-fluid phase transition of the explicit solvent model represented as a mixture of the restricted primitive model (RPM) of ionic fluid and neutral hard spherocylinders (HSC). To this end, we combine two theoretical…

Soft Condensed Matter · Physics 2022-07-26 M. Hvozd , T. Patsahan , O. Patsahan , M. Holovko

Subgradient algorithms for training support vector machines have been quite successful for solving large-scale and online learning problems. However, they have been restricted to linear kernels and strongly convex formulations. This paper…

Machine Learning · Computer Science 2011-11-04 Sangkyun Lee , Stephen J. Wright

Data driven models of dynamical systems help planners and controllers to provide more precise and accurate motions. Most model learning algorithms will try to minimize a loss function between the observed data and the model's predictions.…

Artificial Intelligence · Computer Science 2021-02-12 Clark Zhang , Santiago Paternain , Alejandro Ribeiro

We provide two methods for computation of continuum backstepping kernels that arise in control of continua (ensembles) of linear hyperbolic PDEs and which can approximate backstepping kernels arising in control of a large-scale, PDE system…

Optimization and Control · Mathematics 2024-12-06 Jukka-Pekka Humaloja , Nikolaos Bekiaris-Liberis

Spatial reaction-diffusion models have been employed to describe many emergent phenomena in biological systems. The modelling technique most commonly adopted in the literature implements systems of partial differential equations (PDEs),…

Quantitative Methods · Quantitative Biology 2015-10-05 Christian A. Yates , Mark B. Flegg

We develop a perturbation theory of quantum (and classical) master equations with slowly varying parameters, applicable to systems which are externally controlled on a time scale much longer than their characteristic relaxation time. We…

Quantum Physics · Physics 2017-08-09 Vasco Cavina , Andrea Mari , Vittorio Giovannetti

We use the perturbation method to approximately solve subdiffusion-reaction equations. Within this method we obtain the solutions of the zeroth and the first order. The comparison our analytical solutions with the numerical results shown…

Statistical Mechanics · Physics 2012-01-18 Katarzyna D. Lewandowska , Tadeusz Kosztołowicz , Mateusz Piwnik

Microscopic processes on surfaces such as adsorption, desorption, diffusion and reaction of interacting particles can be simulated using kinetic Monte Carlo (kMC) algorithms. Even though kMC methods are accurate, they are computationally…

Mathematical Physics · Physics 2013-12-24 Yannis Pantazis , Markos Katsoulakis

High-resolution simulations of particle-based kinetic plasma models typically require a high number of particles and thus often become computationally intractable. This is exacerbated in multi-query simulations, where the problem depends on…

Numerical Analysis · Mathematics 2023-07-10 Jan S. Hesthaven , Cecilia Pagliantini , Nicolò Ripamonti

This paper proposes a novel reaction-diffusion system approximation tailored for singular diffusion problems, typified by the fast diffusion equation. While such approximation methods have been successfully applied to degenerate parabolic…

Analysis of PDEs · Mathematics 2026-04-01 Hideki Murakawa , Florian Salin

Gaining insights from realistic dynamical models of biochemical systems can be challenging given their large number of state variables. Model reduction techniques can mitigate this by decreasing complexity by mapping the model onto a…

Computational Engineering, Finance, and Science · Computer Science 2024-11-22 Alexander Leguizamon-Robayo , Antonio Jiménez-Pastor , Micro Tribastone , Max Tschaikowski , Andrea Vandin

We consider the numerical solution of coupled volume-surface reaction-diffusion systems having a detailed balance equilibrium. Based on the conservation of mass, an appropriate quadratic entropy functional is identified and an…

Numerical Analysis · Mathematics 2015-11-04 Herbert Egger , Klemens Fellner , Jan-Frederik Pietschmann , Bao Quoc Tang

A consolidated mathematical formulation of the spherically symmetric mass-transfer problem is presented, with the quasi-stationary approximating equations derived from a perturbation point of view for the leading-order effect. For the…

Mathematical Physics · Physics 2012-09-24 James Q. Feng

We report the findings of new exact analytical solutions to the cosmological fluid equations, namely for the case where the initial conditions are perturbatively close to a spherical top-hat profile. To do so we enable a fluid description…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-28 Cornelius Rampf

In this paper we investigate the approximation of a diffusion model problem with contrasted diffusivity and the error analysis of various nonconforming approximation methods. The essential difficulty is that the Sobolev smoothness index of…

Numerical Analysis · Mathematics 2024-12-20 Alexandre Ern , Jean-Luc Guermond

Symmetric positive semi-definite (SPSD) matrix approximation methods have been extensively used to speed up large-scale eigenvalue computation and kernel learning methods. The standard sketch based method, which we call the prototype model,…

Machine Learning · Computer Science 2016-12-13 Shusen Wang , Zhihua Zhang , Tong Zhang

We investigate the use of reduced-order modelling to run discrete element simulations at higher speeds. Taking a data-driven approach, we run many offline simulations in advance and train a model to predict the velocity field from the mass…

Computational Physics · Physics 2021-03-02 Erik Wallin , Martin Servin

The development of parallel supercomputers allows today the detailed study of the collapse and the fragmentation of prestellar cores with increasingly accurate numerical simulations. Thanks to the advances in sub-millimeter observations, a…

Astrophysics · Physics 2007-09-18 B. Commercon , P. Hennebelle , E. Audit , G. Chabrier , R. Teyssier