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The most general reaction-diffusion model on a Cayley tree with nearest-neighbor interactions is introduced, which can be solved exactly through the empty-interval method. The stationary solutions of such models, as well as their dynamics,…

Statistical Mechanics · Physics 2007-05-23 Laleh Farhang Matin , Amir Aghamohammadi , Mohammad Khorrami

It is widely known that the paradigmatic Chirikov-Taylor model presents enhanced diffusion for specific intervals of its stochasticity parameter due to islands of stability, which are elliptic orbits surrounding accelerator mode fixed…

Chaotic Dynamics · Physics 2009-02-12 Roberto Venegeroles

This paper presents a study of the properties of a matrix model that was introduced to describe transitions between all Wigner surmises of Random Matrix theory. New results include closed-form exact analytical expressions for the…

Mathematical Physics · Physics 2012-03-01 Fredy Zypman

Meta-analysis methods have been widely used to combine results from multiple clinical or genomic studies to increase statistical power and ensure robust and accurate conclusion. Adaptively weighted Fisher's method (AW-Fisher) is an…

Methodology · Statistics 2017-08-18 Zhiguang Huo , Shaowu Tang , Yongseok Park , George Tseng

Normal and anomalous diffusion are ubiquitous in many complex systems [1] . Here, we define a time and space generalized diffusion equation (GDE), which uses fractional-time derivatives and transformed d-path Laplacian operators on…

Physics and Society · Physics 2022-02-02 Fernando Diaz-Diaz , Ernesto Estrada

We tackle unsupervised anomaly detection (UAD), a problem of detecting data that significantly differ from normal data. UAD is typically solved by using density estimation. Recently, deep neural network (DNN)-based density estimators, such…

Machine Learning · Statistics 2019-03-14 Masataka Yamaguchi , Yuma Koizumi , Noboru Harada

Understanding the temporal spread of gene drive alleles -- alleles that bias their own transmission -- through modeling is essential before any field experiments. In this paper, we present a deterministic reaction-diffusion model describing…

Analysis of PDEs · Mathematics 2023-11-01 Léna Kläy , Léo Girardin , Vincent Calvez , Florence Débarre

In this work, we present an effective discrete Edwards-Wilkinson equation aimed to describe the single-file diffusion process. The key physical properties of the system are captured defining an effective elasticity, which is proportional to…

Statistical Mechanics · Physics 2010-06-04 P. M. Centres , S. Bustingorry

We study invariant solutions of a certain class of time-fractional diffusion-wave equations with variable coefficients via Lie symmetry analysis. In physics, the fractional diffusion equation describes transport dynamics that are governed…

We introduce a novel generative model for the representation of joint probability distributions of a possibly large number of discrete random variables. The approach uses measure transport by randomized assignment flows on the statistical…

Machine Learning · Statistics 2025-01-15 Bastian Boll , Daniel Gonzalez-Alvarado , Stefania Petra , Christoph Schnörr

We analyze the time reversed dynamics of generative diffusion models. If the exact empirical score function is used in a regime of large dimension and exponentially large number of samples, these models are known to undergo transitions…

Statistics Theory · Mathematics 2025-11-17 Anand Jerry George , Rodrigo Veiga , Nicolas Macris

This paper develops a threshold model with a time-varying threshold, represented using a wavelet series expansion. The model adequately captures irregular and abrupt variations, as well as smooth changes in the threshold parameter, allowing…

Methodology · Statistics 2026-05-19 Rhea Davis , N. Balakrishna

The random diffusion model is a continuum model for a conserved scalar density field driven by diffusive dynamics where the bare diffusion coefficient is density dependent. We generalize the model from one with a sharp wavenumber cutoff to…

Soft Condensed Matter · Physics 2015-03-13 David D. McCowan , Gene F. Mazenko

Natural populations often show enhanced genetic drift consistent with a strong skew in their offspring number distribution. The skew arises because the variability of family sizes is either inherently strong or amplified by population…

Populations and Evolution · Quantitative Biology 2022-01-13 Takashi Okada , Oskar Hallatschek

A numerical study of the role of anomalous diffusion in front propagation in reaction-diffusion systems is presented. Three models of anomalous diffusion are considered: fractional diffusion, tempered fractional diffusion, and a model that…

Pattern Formation and Solitons · Physics 2014-09-11 D. del-Castillo-Negrete

Active particles often swim in confined environments. The transport mechanisms, especially the global one as reflected by the Taylor dispersion model, are of great practical interest to various applications. For active dispersion process in…

Fluid Dynamics · Physics 2023-06-22 Weiquan Jiang , Guoqian Chen

Diffusion generative models unlock new possibilities for inverse problems as they allow for the incorporation of strong empirical priors in scientific inference. Recently, diffusion models are repurposed for solving inverse problems using…

In this work, we propose a new inference procedure for understanding non-stationary processes, under the framework of evolutionary spectra developed by Priestley. Among various frameworks of modeling non-stationary processes, the…

Methodology · Statistics 2019-02-20 Yu Xiang , Jie Ding , Vahid Tarokh

We consider the problem of parameter estimation for an ergodic diffusion with Fisher-Snedecor invariant distribution, to be called Fisher-Snedecor diffusion. We compute the spectral representation of its transition density, which involves a…

Statistics Theory · Mathematics 2010-07-29 F. Avram , N. N. Leonenko , N. Šuvak

We derive explicit solutions for time-fractional anomalous diffusion equations with diffusivity coefficients that depend on both space and time variables. These solutions are expressed in Fox-H and generalized Wright functions, which are…

Analysis of PDEs · Mathematics 2024-05-14 Ganbileg Bat-Ochir , Khongorzul Dorjgotov , Uuganbayar Zunderiya
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