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The essentials of fractional calculus according to different approaches that can be useful for our applications in the theory of probability and stochastic processes are established. In addition to this, from this fractional integral one…

Mathematical Physics · Physics 2013-07-31 Nicy Sebastian

A fractional diffusion equation with advection term is rigorously derived from a kinetic transport model with a linear turning operator, featuring a fat-tailed equilibrium distribution and a small directional bias due to a given vector…

Analysis of PDEs · Mathematics 2015-10-19 Pedro Aceves-Sanchez , Christian Schmeiser

In this work we present a generalised viscoelastic model using distributed-order derivatives. The model consists of two distributed-order elements (distributed springpots) connected in series, as in the Maxwell model. The new model…

Classical Physics · Physics 2022-12-28 Luis Ferrás , Maria Luisa Morgado , Magda Rebelo

This paper deals with the numerical modeling of wave propagation in porous media described by Biot's theory. The viscous efforts between the fluid and the elastic skeleton are assumed to be a linear function of the relative velocity, which…

Fluid Dynamics · Physics 2015-05-20 Guillaume Chiavassa , Bruno Lombard

The fractional diffusion-wave equation (FDWE) is a recent generalization of diffusion and wave equations via time and space fractional derivatives. The equation underlies Levy random walk and fractional Brownian motion and is foremost…

Mathematical Physics · Physics 2007-05-23 W. Chen , S. Holm

This article introduces a novel construction of the two-dimensional fractional Brownian motion (2D fBm) with dependent components. Unlike similar models discussed in the literature, our approach uniquely accommodates the full range of model…

In this paper we discuss the uniaxial propagation of transient waves within a semi-infinite viscoelastic Bessel medium. First, we provide the analytic expression for the response function of the material as we approach the wave-front. To do…

Mathematical Physics · Physics 2017-05-22 Ivano Colombaro , Andrea Giusti , Francesco Mainardi

In many applications, and in particular in seismology, realistic propagation media disperse and attenuate waves. This dissipative behavior can be taken into account by using a viscoacoustic propagation model, which incorporates a complex…

Numerical Analysis · Mathematics 2025-10-20 Jean-Philippe Groby , Chrysoula Tsogka

We consider a sparse high-dimensional varying coefficients model with random effects, a flexible linear model allowing covariates and coefficients to have a functional dependence with time. For each individual, we observe discretely sampled…

Statistics Theory · Mathematics 2021-10-14 Michael Law , Ya'acov Ritov

A deterministic pathogen transmission model based on high-fidelity physics has been developed. The model combines computational fluid dynamics and computational crowd dynamics in order to be able to provide accurate tracing of viral matter…

Numerical Analysis · Mathematics 2022-10-26 Rainald Löhner , Harbir Antil , Juan Marcelo Gimenez , Sergio Idelsohn , Eugenio Oñate

Attenuation of ultrasound waves varies with tissue composition, hence its estimation offers great potential for tissue characterization and diagnosis and staging of pathology. We recently proposed a method that allows to spatially…

Medical Physics · Physics 2020-10-13 Richard Rau , Ozan Unal , Dieter Schweizer , Valery Vishnevskiy , Orcun Goksel

This study investigates the ultraslow diffusion by a spatial structural derivative, in which the exponential function exp(x)is selected as the structural function to construct the local structural derivative diffusion equation model. The…

Statistical Mechanics · Physics 2017-06-14 Wei Xu , Wen Chen , Yingjie Liang , Jose Weberszpil

We investigate the nonlinear vibration of a fractional viscoelastic cantilever beam, subject to base excitation, where the viscoelasticity takes the general form of a distributed-order fractional model, and the beam curvature introduces…

Numerical Analysis · Mathematics 2019-09-06 Pegah Varghaei , Ehsan Kharazmi , Jorge L. Suzuki , Mohsen Zayernouri

In this chapter we provide an introduction to fractional dissipative partial differential equations (PDEs) with a focus on trying to understand their dynamics. The class of PDEs we focus on are reaction-diffusion equations but we also…

The importance of ultrasound is well established in the imaging of human tissue. In order to enhance image quality by exploiting nonlinear effects, recently techniques such as harmonic imaging and nonlinearity parameter tomography have been…

Analysis of PDEs · Mathematics 2025-02-13 Barbara Kaltenbacher

Analytic first and second derivatives of the energy are developed for the fragment molecular orbital method interfaced with molecular mechanics in the electrostatic embedding scheme at the level of Hartree-Fock and density functional…

Chemical Physics · Physics 2020-05-19 Hiroya Nakata , Dmitri G. Fedorov

We consider the problem of waves propagating in a viscoelastic solid. For the material properties of the solid we consider both classical and fractional differentiation in time versions of the Zener, Maxwell, and Voigt models, where the…

Numerical Analysis · Mathematics 2018-02-06 Thomas Brown , Shukai Du , Hasan Eruslu , Francisco-Javier Sayas

Considered here is the derivation of partial differential equations arising in pulsatile flow in pipes with viscoelastic walls. The equations are asymptotic models describing the propagation of long-crested pulses in pipes with cylindrical…

Fluid Dynamics · Physics 2020-02-20 Dimitrios Mitsotakis , Denys Dutykh , Qian Li , Elijah Peach

We present a semi-analytical model to simulate bidirectional reflectance distribution function (BRDF) spectra of a rough slab layer containing impurities. This model has been optimized for fast computation in order to analyze hyperspectral…

We introduce bidirectional edge diffraction response function (BEDRF), a new approach to model wave diffraction around edges with path tracing. The diffraction part of the wave is expressed as an integration on path space, and the wave-edge…

Sound · Computer Science 2023-06-06 Chunxiao Cao , Zili An , Zhong Ren , Dinesh Manocha , Kun Zhou