### Recent Submissions

• #### 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 ...
• #### Concurent multi-scale physical parametrization of fire-spotting: A study on the role of macro- and meso-scale characteristics of the system ﻿

(Advances in Forest Fire Research, 2018)
The strong impact of wildfires in terms of lives and homes lost and of damage to ecosystems, calls for an urgent improvement in the risk management. The aim of the present research is the improvement of these software ...
• #### Wildfire propagation modelling ﻿

(Geophysical Research Abstracts Vol. 20, 2018)
Wildfires are a concrete problem with a strong impact on human life, property and the environment, because they cause disruption and are an important source of pollutants. Climate change and ...
• #### Langevin equation in complex media and anomalous diffusion ﻿

(Journal of the Royal Society Interface, 2018-07-30)
The problem of biological motion is a very intriguing and topical issue. Many efforts are being focused on the development of novel modelling approaches for the description of anomalous diffusion in biological systems, such ...
• #### On the merits of sparse surrogates for global sensitivity analysis of multi-scale nonlinear problems: Application to turbulence and fire-spotting model in wildland fire simulators ﻿

(Communications in Nonlinear Science and Numerical Simulation, 2019-02)
Many nonlinear phenomena, whose numerical simulation is not straightforward, depend on a set of parameters in a way which is not easy to predict beforehand. Wildland fires in presence of strong winds fall into this category, ...
• #### The role of the environment in front propagation ﻿

(Proceedings of the 18th International Conference on Computational and Mathematical Methods in Science and Engineering, CMMSE 2018 July 9–14, 2018, 2018-07-09)
In this work we study the role of a complex environment in the propagation of a front with curvature-dependent speed. The motion of the front is split into a drifting part and a fluctuating part. The drifting part is ...
• #### Modeling of birth-death and diffusion processes in biological complex environments ﻿

(2018-04-20)
This thesis is centered on the theory of stochastic processes and their applications in biological systems characterized by a complex environment. Three case studies have been modeled by the use of the three fundamental ...
• #### Quasi-probability Approach for Modelling Local Extinction and Counter-gradient in Turbulent Premixed Combustion ﻿

(Proceedings/Extended Abstract Book (6 pages) of the XLI Meeting of the Italian Section of the Combustion Institute, 2018-05-23)
In opposition to standard probability distributions, quasi-probability distributions can have negative values which highlight nonclassical properties of the corresponding system. In quantum mechanics, such negative values ...