### Recent Submissions

• #### A generalized Stefan model accounting for system memory and non-locality ﻿

(International Communications in Heat and Mass Transfer, 2020-05)
The Stefan problem, involving the tracking of an evolving phase-change front, is the prototypical example of a moving boundary problem. In basic one- dimensional problems it is well known that the front advances as the ...
• #### A hypothesis about parallelism vs. seriality in dreams ﻿

(Front. Psychol., 2019-10-10)
The current article discusses the hypothesis about parallelism vs. Seriality in dreams. The process of dream building implies the construction of a complex network of closely interrelated sources. On the other hand, the ...
• #### Gaussian processes in complex media: new vistas on anomalous diffusion ﻿

(Front. Phys., 2019-09)
Normal or Brownian diffusion is historically identified by the linear growth in time of the variance and by a Gaussian shape of the displacement distribution. Processes departing from the at least one of the above conditions ...
• #### Front Propagation in Random Media ﻿

(2019)
This PhD thesis deals with the problem of the propagation of fronts under random circumstances. A statistical model to represent the motion of fronts when are evolving in a media characterized by microscopical randomness ...
• #### Stochastic processes for anomalous diffusion ﻿

(2019)
Anomalous diffusion is a diffusion process which Mean Square Displacement (MSD) is not a linear funtion of time, what is known as normal diffusion. When the relation is faster than linear, it is called superdiffusion and ...
• #### Single-trajectory spectral analysis of scaled Brownian motion ﻿

(New Journal of Physics, 2019-06)
A standard approach to study time-dependent stochastic processes is the power spectral density (PSD), an ensemble-averaged property defined as the Fourier transform of the autocorrelation function of the process in the ...
• #### Reduced description method in the kinetic theory of Brownian motion with active fluctuations ﻿

(Journal of Physics A: Mathematical and Theoretical, 2019-09-01)
We develop a microscopic approach to the kinetic theory of many-particle systems with dissipative and potential interactions in presence of active fluctuations. The approach is based on a generalization of Bogolyubov–Peletminskii ...
• #### On the propagation of nonlinear transients of temperature and pore pressure in a thin porous boundary layer between two rocks. ﻿

(Journal of Hydrology, 2019)
The dynamics of transients of fluid-rock temperature, pore pressure, pollutants in porous rocks are of vivid interest for fundamental problems in hydrological, volcanic, hydrocarbon systems, deep oil drilling. This can ...
• #### Restoring property of the Michelson-Sivashinsky equation ﻿

(Combustion Science and Technology, 2019)
In this paper we propose a derivation of the Michelson-Sivashinsky (MS) equation that is based on front propagation only, in opposition to the classical derivation based also on the flow field. Hence, the characteristics ...
• #### Stochastic spatial models in ecology: a statistical physics approach ﻿

(Journal of Statistical Physics, 2017-11-21)
Ecosystems display a complex spatial organization. Ecologists have long tried to characterize them by looking at how different measures of biodiversity change across spatial scales. Ecological neutral theory has provided ...
• #### Fractional kinetics in random/complex media ﻿

(Handbook of Fractional Calculus with Applications Volume 5 Applications in Physics, Part B, 2019)
In this chapter, we consider a randomly-scaled Gaussian process and discuss a number of applications to model fractional diffusion. Actually, this approach can be understood as a Gaussian diffusion in a medium characterized ...
• #### Fractional Brownian motion in a finite interval: correlations effect depletion or accretion zones of particles near boundaries ﻿

(New Journal of Physics, 2019-02)
Fractional Brownian motion (FBM) is a Gaussian stochastic process with stationary, long-time correlated increments and is frequently used to model anomalous diffusion processes. We study numerically FBM confined to a finite ...
• #### Surrogate-based uncertainty and sensitivity analysis for bacterial invasion in multi-species biofilm modeling ﻿

(Communications Nonlinear Sciences and Numerical Simulation, 2019)
In this work, we present a probabilistic analysis of a detailed one-dimensional biofilm model that explicitly accounts for planktonic bacterial invasion in a multi-species biofilm. The objective is (1) to quantify and ...
• #### Finite-energy Lévy-type motion through heterogeneous ensemble of Brownian particles ﻿

(Journal of Physics A: Mathematical and Theoretical, 2019-02-01)
Complex systems are known to display anomalous diffusion, whose signature is a space/time scaling $x \sim t^\delta$ with $\delta \neq 1/2$ in the probability density function (PDF). Anomalous diffusion can emerge jointly ...
• #### Fire-spotting generated fires. Part I: The role of atmospheric stability ﻿

(Applied Mathematical Modelling, 2019-02)
This is the first part of two papers concerning fire-spotting generated fires. In this part we deal with the impact of macroscale factors, such as the atmospheric stability, and in the second part we deal with mesoscale ...
• #### Modeling anomalous heat diffusion: Comparing fractional derivative and non-linear diffusivity treatments ﻿

(International Journal of Thermal Sciences, 2018-11)
In the Fourier heat conduction equation, when the flux definition is expressed as the product of a constant diffusivity and the temperature gradient, the characteristic length scale evolves as the square root of time. ...
• #### Modeling non-stationarities in high-frequency financial time series ﻿

(Physica A: Statistical Mechanics and its Applications, 2019-01)
We study tick-by-tick financial returns for the FTSE MIB index of the Italian Stock Exchange (Borsa Italiana). We confirm previously detected non-stationarities. Scaling properties reported before for other high-frequency ...
• #### Centre-of-mass like superposition of Ornstein-Uhlenbeck processes: A pathway to non-autonomous stochastic differential equations and to fractional diffusion ﻿

(Fractional Calculus and Applied Analysis, 2018-10-25)
We consider an ensemble of Ornstein–Uhlenbeck processes featuring a population of relaxation times and a population of noise amplitudes that characterize the heterogeneity of the ensemble. We show that the centre-of-mass ...
• #### RandomFront 2.3 A physical parametrisation of fire-spotting for operational fire spread models: Implementation in WRF-Sfire and response analysis with LSFire+ ﻿

(Geoscientific Model Development, 2018-12)
Fire-spotting is often responsible for a dangerous flare up in the wildfire and causes secondary ignitions isolated from the primary fire zone leading to perilous situations. The main aim of the present research to provide ...
• #### Crossover from anomalous to normal diffusion: truncated power-law noise correlations and applications to dynamics in lipid bilayers ﻿

(New Journal of Physics, 2018-10-18)
The emerging diffusive dynamics in many complex systems shows a characteristic crossover behaviour from anomalous to normal diffusion which is otherwise fitted by two independent power-laws. A prominent example for a ...