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Motivated by population studies of Diffusion Tensor Imaging, the paper investigates the use of mean-based and dispersion-based permutation tests to define and compute the significance of a statistical test for data taking values on…

Statistics Theory · Mathematics 2013-05-07 Anne Collard , Christophe Phillips , Rodolphe Sepulchre

Heat kernel expansion coefficients are calculated for vacuum fluctuations with distributional background potentials and field strengths. Terms up to and including t^5/2 are presented.

High Energy Physics - Theory · Physics 2009-10-31 Ian G Moss

We develop in this note a homogenization method to tackle the problem of a diffusion process through a cracked medium. We show that the cracked surface of the domain induces a source term in the homogenized equation. We assume that the…

Analysis of PDEs · Mathematics 2013-05-28 Xavier Blanc , Benjamin Edouard Peigney

Diffusion condensation is a dynamic process that yields a sequence of multiscale data representations that aim to encode meaningful abstractions. It has proven effective for manifold learning, denoising, clustering, and visualization of…

Machine Learning · Computer Science 2023-01-06 Guillaume Huguet , Alexander Tong , Bastian Rieck , Jessie Huang , Manik Kuchroo , Matthew Hirn , Guy Wolf , Smita Krishnaswamy

Translational diffusion coefficients are routinely estimated from molecular dynamics simulations. Linear fits to mean squared displacement (MSD) curves have become the de facto standard, from simple liquids to complex biomacromolecules.…

Computational Physics · Physics 2020-11-20 Jakob Tómas Bullerjahn , Sören von Bülow , Gerhard Hummer

Diffusion generative models have recently been applied to domains where the available data can be seen as a discretization of an underlying function, such as audio signals or time series. However, these models operate directly on the…

Machine Learning · Computer Science 2023-02-28 Gavin Kerrigan , Justin Ley , Padhraic Smyth

We obtain two-sided heat kernel estimates for Riemannian manifolds with ends with mixed boundary condition, provided that the heat kernels for the ends are well understood. These results extend previous results of Grigor'yan and…

Differential Geometry · Mathematics 2025-01-15 Emily Dautenhahn , Laurent Saloff-Coste

Self-diffusion coefficients, $D^*$, are routinely estimated from molecular dynamics simulations by fitting a linear model to the observed mean-squared displacements (MSDs) of mobile species. MSDs derived from simulation exhibit statistical…

Statistical Mechanics · Physics 2026-01-05 Andrew R. McCluskey , Samuel W. Coles , Benjamin J. Morgan

We discuss a class of diffusion-type partial differential equations on a bounded interval and discuss the possibility of replacing the boundary conditions by certain linear conditions on the moments of order 0 (the total mass) and of…

Analysis of PDEs · Mathematics 2018-12-21 Delio Mugnolo , Serge Nicaise

It is well-known that stochastic processes on fractal spaces or in certain random media exhibit anomalous heat kernel behaviour. One manifestation of such irregular behaviour is the presence of fluctuations in the short- or long-time…

Probability · Mathematics 2023-10-18 Sebastian Andres , David Croydon , Takashi Kumagai

Modeling radio frequency (RF) signal propagation is essential for understanding the environment, as RF signals offer valuable insights beyond the capabilities of RGB cameras, which are limited by the visible-light spectrum, lens coverage,…

Machine Learning · Computer Science 2025-10-07 Kyoungjun Park , Yifan Yang , Changhan Ge , Lili Qiu , Shiqi Jiang

Diffusion models have had a profound impact on many application areas, including those where data are intrinsically infinite-dimensional, such as images or time series. The standard approach is first to discretize and then to apply…

Machine Learning · Statistics 2025-06-09 Jakiw Pidstrigach , Youssef Marzouk , Sebastian Reich , Sven Wang

The purpose of the paper is to find explicit formulas describing the joint distributions of the first hitting time and place for half-spaces of codimension one for a diffusion in $\R^{n+1}$, composed of one-dimensional Bessel process and…

Probability · Mathematics 2010-06-18 T. Byczkowski , J. Malecki , M. Ryznar

On doubling metric measure spaces endowed with a strongly local regular Dirichlet form, we show some characterisations of pointwise upper bounds of the heat kernel in terms of global scale-invariant inequalities that correspond respectively…

Analysis of PDEs · Mathematics 2013-11-15 Salahaddine Boutayeb , Thierry Coulhon , Adam Sikora

Let M be a complete Riemannian manifold with a free cocompact Z^k-action. Let k(t,x,y) be the heat kernel on M. We compute the asymptotics of k(t,x,y) in the limit in which t goes to infinity and d(x,y) is comparable to sqrt{t}. We show…

dg-ga · Mathematics 2008-02-03 John Lott

We construct a new random probability measure on the sphere and on the unit interval which in both cases has a Gibbs structure with the relative entropy functional as Hamiltonian. It satisfies a quasi-invariance formula with respect to the…

Probability · Mathematics 2007-05-23 Max-K von Renesse , Karl-Theodor Sturm

The latent space of diffusion model mostly still remains unexplored, despite its great success and potential in the field of generative modeling. In fact, the latent space of existing diffusion models are entangled, with a distorted mapping…

Machine Learning · Computer Science 2024-07-17 Jaehoon Hahm , Junho Lee , Sunghyun Kim , Joonseok Lee

This is a review of statistical inference methodology for stochastic differential equations driven by fractional Brownian motion, otherwise called fractional diffusions. The first section reviews the theory needed to rigorously define them.…

Probability · Mathematics 2026-04-07 Pablo Ramses Alonso-Martin , Horatio Boedihardjo , Anastasia Papavasiliou

We extend the diffusion-map formalism to data sets that are induced by asymmetric kernels. Analytical convergence results of the resulting expansion are proved, and an algorithm is proposed to perform the dimensional reduction. In this work…

Machine Learning · Computer Science 2024-01-24 Alvaro Almeida Gomez , Antonio Silva Neto , Jorge zubelli

A diffusion spider is a strong Markov process with continuous paths taking values on a graph with one vertex and a finite number of edges (of infinite length). An example is Walsh's Brownian spider where the process on each edge behaves as…

Probability · Mathematics 2022-09-26 Jukka Lempa , Ernesto Mordecki , Paavo Salminen
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