Search results for "Matematica"

On the relations between audio features and room acoustic parameters of auralizations

2013

The usual parameters in room acoustics are used to quantify the acoustic characteristics of rooms and their relation to the subjective perception of transmitted signals. Audio features (calculated with MIRToolbox) have been designed to study the relationships between the characteristics of musical audio files and their subjective perception. Both musical characteristics and acoustic parameters are oriented towards acoustic perception. By using auralizations with calibrated models of auditoriums and tools from the MIRtoolbox it is possible to jointly work with the calculation of audio features and room parameters. In this work, the statistical correlations between C80, STI, D50, EDT, RT and …

Effective thermal conductivity of superfluid helium in short channels

2014

The aim of this paper is to explore how the effective thermal conductivity of small channels filled with superfluid helium II in the laminar regime separates from the classical Landau expression as the channel becomes shorter. The Landau expression is valid for fully developed Poiseuille flow for the normal component, and therefore is suitable for long channels. By taking into account entrance effects, we show a transition from a heat flux proportional to ∆T /l (Landau regime) for long channels, to a heat flux proportional to l^(1/3) (∆T /l)^(2/3) for short channels.

SIVS epidemic model with stochastic perturbation

2010

Processi cognitivi e soluzioni dei problemi: studenti italiani e studenti cinesi

2011

Obiettivo primario della ricerca sulla quale ho lavorato negli ultimi quattro anni è stato quello di riflettere sulle questioni riguardanti le Matematiche Elementari in una visione quanto più ampia possibile, alla luce di una scuola sempre più “diversificata”, multiculturale e globalizzata, trattando in maniera diretta non soltanto le problematiche strettamente riferite ai contenuti disciplinari relativi specificatamente al pensiero algebrico e geometrico per la scuola Primaria e Secondaria, ma anche quelli che in molti casi possono definirsi come gli aspetti storico-epistemologici della disciplina discussa in aula con gli allievi. Quale didattica disciplinare nella classe del terzo millenn…

Regular and singular pulse and front solutions and possible isochronous behavior in the short-pulse equation: Phase-plane, multi-infinite series and …

2014

In this paper we employ three recent analytical approaches to investigate the possible classes of traveling wave solutions of some members of a family of so-called short-pulse equations (SPE). A recent, novel application of phase-plane analysis is first employed to show the existence of breaking kink wave solutions in certain parameter regimes. Secondly, smooth traveling waves are derived using a recent technique to derive convergent multi-infinite series solutions for the homoclinic (heteroclinic) orbits of the traveling-wave equations for the SPE equation, as well as for its generalized version with arbitrary coefficients. These correspond to pulse (kink or shock) solutions respectively o…

First-order linear differential equations whose data are complex random variables: Probabilistic solution and stability analysis via densities

2022

[EN] Random initial value problems to non-homogeneous first-order linear differential equations with complex coefficients are probabilistically solved by computing the first probability density of the solution. For the sake of generality, coefficients and initial condition are assumed to be absolutely continuous complex random variables with an arbitrary joint probability density function. The probability of stability, as well as the density of the equilibrium point, are explicitly determined. The Random Variable Transformation technique is extensively utilized to conduct the overall analysis. Several examples are included to illustrate all the theoretical findings.

I poligoni: dai mosaici dell’Alhambra alle incisioni di Escher

2019

Descrizione delle attività svolte durante l'omonimo laboratorio tenuto per il PLS matematica nell'anno 2018

Análisis de los modelos matemáticos producidos durante la resolución de problemas de Fermi

2017

[EN] In this paper, we present an analysis of written productions of 16 year-old students while solving Estimation Problems involving Big Numbers (EPiBN). This kind of problems is a particular type of Fermi problems and allows us to introduce modelling processes in Secondary school classrooms. Our analysis supports on the characterization of mathematical models developed by students based on the model definition of Lesh and Harel. The results show that, through the analysis of EPiBN resolutions, differentiating aspects can be distinguished between the models produced by students without modelling experience of those produced by students with prior experience, especially in the concepts and …

Non-parametric probabilistic forecasting of academic performance in Spanish high school using an epidemiological modelling approach

2013

Academic underachievement is a concern of paramount importance in Europe, and particularly in Spain, where around of 30% of the students in the last two courses in high school do not achieve the minimum knowledge academic requirement. In order to analyse this problem, we propose a mathematical model via a system of ordinary differential equations to study the dynamics of the academic performance in Spain. Our approach is based on the idea that both, good and bad study habits, are a mixture of personal decisions and influence of classmates. Moreover, in order to consider the uncertainty in the estimation of model parameters, a bootstrapping approach is employed. This technique permits to for…

Existence and multiplicity of solutions for Dirichlet problems involving nonlinearities with arbitrary growth.

2014

In this article we study the existence and multiplicity of solutions for the Dirichlet problem $$\displaylines{ -\Delta_p u=\lambda f(x,u)+ \mu g(x,u)\quad\hbox{in }\Omega,\cr u=0\quad\hbox{on } \partial \Omega }$$ where $\Omega$ is a bounded domain in $\mathbb{R}^N$, $f,g:\Omega \times \mathbb{R}\to \mathbb{R}$ are Caratheodory functions, and $\lambda,\mu$ are nonnegative parameters. We impose no growth condition at $\infty$ on the nonlinearities f,g. A corollary to our main result improves an existence result recently obtained by Bonanno via a critical point theorem for $C^1$ functionals which do not satisfy the usual sequential weak lower semicontinuity property.