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Modeling of longitudinal data often requires diffusion models that incorporate overall time-dependent, nonlinear dynamics of multiple components and provide sufficient flexibility for subject-specific modeling. This complexity challenges…

Methodology · Statistics 2017-01-31 Mareile Große Ruse , Adeline Samson , Susanne Ditlevsen

A modification of the Drude dispersive model based on fractional time derivative is presented. The dielectric susceptibility is calculated analytically and simulated numerically, showing a good agreement between theoretical description and…

Computational Physics · Physics 2021-03-23 Karol Karpiński , Sylwia Zielińska - Raczyńska , David Ziemkiewicz

We consider the problem of statistical inference for the effective dynamics of multiscale diffusion processes with (at least) two widely separated characteristic time scales. More precisely, we seek to determine parameters in the effective…

Statistics Theory · Mathematics 2013-05-30 Sebastian Krumscheid , Grigorios A. Pavliotis , Serafim Kalliadasis

The problem of sequential anomaly detection and identification is considered, where multiple data sources are simultaneously monitored and the goal is to identify in real time those, if any, that exhibit ``anomalous" statistical behavior.…

Statistics Theory · Mathematics 2024-12-09 Aristomenis Tsopelakos , Georgios Fellouris

In this article, we consider the inverse problems of determining the damping coefficient appearing in the wave equation. We prove the unique determination of the coefficient from the data coming from a single coincident source-receiver…

Analysis of PDEs · Mathematics 2019-06-24 Manmohan Vashisth

Latent defect screening is challenged by extremely low failure rates, high-dimensional test data, and absence of labeled anomalies. We propose the first unsupervised anomaly detection framework incorporating a Diffusion Transformer. Raw…

Machine Learning · Computer Science 2026-05-27 Yuxuan Yin , Chen He , Todd Jacobs , Jialei He , Boxun Xu , Robert Jin , Peng Li

We investigate sequential change point estimation and detection in univariate nonparametric settings, where a stream of independent observations from sub-Gaussian distributions with a common variance factor and piecewise-constant but…

Statistics Theory · Mathematics 2020-11-16 Yi Yu , Oscar Hernan Madrid Padilla , Daren Wang , Alessandro Rinaldo

This article investigates the non-stationary reaction-diffusion-advection equation, emphasizing solutions with internal layers and the associated inverse problems. We examine a nonlinear singularly perturbed partial differential equation…

Numerical Analysis · Mathematics 2025-02-06 Dmitrii Chaikovskii , Ye Zhang , Aleksei Liubavin

We consider an inverse source problem in the two-time-scale mobile-immobile fractional diffusion model from partial interior observation. Theoretically, we combine the fractional Duhamel's principle with the weak vanishing property to…

Numerical Analysis · Mathematics 2026-04-02 Zhiwei Yang , Yikan Liu

Difference schemes for the time-fractional diffusion equation with variable coefficients and nonlocal boundary conditions containing real parameters $\alpha$ and $\beta$ are considered. By the method of energy inequalities, for the solution…

Numerical Analysis · Mathematics 2015-03-27 A. A. Alikhanov

In the paper, we discuss the reconstruction of scalar parameters in a linear diffusion equation with fractional in time differential operators and with additional nonlocal (convolution) terms, which incorporate memory effects in models.…

Analysis of PDEs · Mathematics 2026-03-30 Sergii V. Siryk , Lidiia Tereshchenko , Nataliya Vasylyeva

Using a quantum electrodynamic framework, we calculate the off-resonant scattering of a broad-band X-ray pulse from a sample initially prepared in an arbitrary superposition of electronic states. The signal consists of single-particle…

Chemical Physics · Physics 2015-06-19 Kochise Bennett , Jason D. Biggs , Yu Zhang , Konstantin E. Dorfman , Shaul Mukamel

The motion of self-propelled particles is modeled as a persistent random walk. An analytical framework is developed that allows the derivation of exact expressions for the time evolution of arbitrary moments of the persistent walk's…

Soft Condensed Matter · Physics 2015-07-28 Zeinab Sadjadi , M. Reza Shaebani , Heiko Rieger , Ludger Santen

A tracer particle is called anomalously diffusive if its mean squared displacement grows approximately as $\sigma^2 t^{\alpha}$ as a function of time $t$ for some constant $\sigma^2$, where the diffusion exponent satisfies $\alpha \neq 1$.…

Soft Condensed Matter · Physics 2018-10-17 Kui Zhang , Katelyn P. R. Crizer , Mark H. Schoenfisch , David B. Hill , Gustavo Didier

We introduce a new method for the estimation of the angular parameters [i.e., central directions of arrival (DOAs) and angular spreads] of multiple non-circular and incoherently-distributed (ID) sources and thoroughly analyze its…

Signal Processing · Electrical Eng. & Systems 2019-01-07 Sonia Ben Hassen , Faouzi Bellili , Abdelaziz Samet , Sofiène Affes

In this article, we introduce a novel non-parametric predictor, based on conditional expectation, for the unknown diffusion coefficient function $\sigma$ in the stochastic partial differential equation $Lu = \sigma(u)\dot{W}$, where $L$ is…

Statistics Theory · Mathematics 2025-09-17 Martin Andersson , Benny Avelin , Valentin Garino , Pauliina Ilmonen , Lauri Viitasaari

n a recent experiment, we reported the time-domain intensity noise measurement of a single photon source relying on single molecule fluorescence control. In this article we present data processing, starting from photocount timestamps. The…

Quantum Physics · Physics 2009-11-10 Romain Alleaume , Francois Treussart , Jean-Michel Courty , Jean-Francois Roch

We follow the trajectories of phase singularities at nulls of intensity in the speckle pattern of waves transmitted through random media as the frequency of the incident radiation is scanned in microwave experiments and numerical…

Disordered Systems and Neural Networks · Physics 2015-06-19 Xiaojun Cheng , Yitzchak Lockerman , Azriel Z. Genack

We are concerned with an inverse problem associated with the fractional Helmholtz system that arises from the study of viscoacoustics in geophysics and thermoviscous modelling of lossy media. We are particularly interested in the case that…

Analysis of PDEs · Mathematics 2018-03-28 Xinlin Cao , Hongyu Liu

Diffusive dynamics abound in nature and have been especially studied in physical, biological, and financial systems. These dynamics are characterised by a linear growth of the mean squared displacement (MSD) with time. Often, the conditions…

Statistical Mechanics · Physics 2025-11-14 Alvaro Lanza , Xiang Qu , Stefano Bo