Search results for "Processes"

Nonparametric intensity estimation in space-time point processes and application to seismological problems

2008

Space-Time Forecasting of Seismic Events in Chile

2017

The aim of this work is to study the seismicity in Chile using the ETAS (epidemic type aftershock sequences) space‐time approach. The proposed ETAS model is estimated using a semi‐parametric technique taking into account the parametric and nonparametric components corresponding to the triggered and background seismicity, respectively. The model is then used to predict the temporal and spatial intensity of events for some areas of Chile where recent large earthquakes (with magnitude greater than 8.0 M) occurred.

Models and methods for space and space-time interactions in complex point processes with applications on earthquakes

Joint second-order parameter estimation for spatio-temporal log-Gaussian Cox processes

2018

We propose a new fitting method to estimate the set of second-order parameters for the class of homogeneous spatio-temporal log-Gaussian Cox point processes. With simulations, we show that the proposed minimum contrast procedure, based on the spatio-temporal pair correlation function, provides reliable estimates and we compare the results with the current available methods. Moreover, the proposed method can be used in the case of both separable and non-separable parametric specifications of the correlation function of the underlying Gaussian Random Field. We describe earthquake sequences comparing several Cox model specifications.

Weighted local second-order statistics for complex spatio-temporal point processes

2019

Spatial, temporal, and spatio-temporal point processes, and in particular Poisson processes, are stochastic processes that are largely used to describe and model the distribution of a wealth of real phenomena. When a model is fitted to a set of random points, observed in a given multidimensional space, diagnostic measures are necessary to assess the goodness-of-fit and to evaluate the ability of that model to describe the random point pattern behaviour. The main problem when dealing with residual analysis for point processes is to find a correct definition of residuals. Diagnostics of goodness-of-fit in the theory of point processes are often considered through the transformation of data in…

El nost Milan: il rap dei ‘nuovi italiani', tra riappropriazioni urbane e rivendicazioni identitarie

2019

italianoFin dai suoi esordi, la cultura hip-hop e stata attraversata da una forte connotazione in senso spaziale, che ne ha variamente contraddistinto i diversi elementi. La citta post-industriale, specie lungo i suoi margini e nei suoi interstizi, rappresenta infatti un sito cruciale a partire dal quale la storia ma, soprattutto, la geografia del rap sono andate col tempo costruendosi. Obiettivo di questo articolo e di riflettere criticamente sulla relazione fra rap e spazi urbani in Italia alla luce delle complesse costruzioni culturali, sociali e politiche che la sottendono, con particolare riferimento a due rapper milanesi della cosiddetta generazione dei nuovi italiani, Zanko e Ghali. …

Realization of time-resolved two-vacuum-ultraviolet-photon ionization

2009

International audience; Ultrafast dynamics of excited molecules is studied through time-resolved two-vacuum-ultraviolet (vuv)- photon ionization using a nonlinear volume autocorrelator unit. The two-vuv-photon process is induced by the intense fifth harmonic radiation of a femtosecond Ti:sapphire laser. In a proof-of-principle experiment, ultrafast dynamics of excited ethylene and oxygen molecules are investigated. Molecular decay times are deduced by comparing the experimental data with the results of a numerical model that accounts for the spatial and temporal characteristics of the harmonic field. The present experiments pave a convenient way for time domain investigations in the vuv-xuv s…

Salivary proteome and sensitivity to bitterness

2010

Among the various factors that dictate food choices, the sensorial acceptability and the in-mouth perception of food are essential. For example, bitterness is partly responsible for the rejection of some vegetables by some consumers. In this study, the aim is to evaluate if the salivary environment of an individual plays a role in his sensitivity to bitter taste

Monitoring of stress distribution in damaged small-scale masonry walls by using two innovative sensors

2023

Structural Health Monitoring (SHM) represents a strategic solution for the preservation of cultural heritage buildings. Existing masonry structures often suffer reductions in mechanical performances due to physiological aging of material constituents, external actions, and effect of catastrophic natural events. In many cases, the prompt prediction of damage in masonry elements is difficult and it can cause sudden collapses, compromising the safety of people. The proposed experimental study examines the effectiveness of two low-cost and innovative stress sensors, i.e. piezoelectric and capacitive stress sensors, for SHM of masonry structures. To this scope, the sensors were embedded in the m…

Dynamique fluvial, changement global et pression anthropique dans le bassin, le cours et le delta de l'Ébre

2017

Le fonctionnement des rivières du bassin de l’Èbre a subi d’importants changements depuis 1950. Il s’agit d’un processus rapide et très marqué, de simplification et de stabilisation sur le fleuve principal et sur ses principaux affluents pyrénéens. Ce processus s’est manifesté par des changements dans la morphologie fluviale, le développement de la végétation sur les lits, un rétrécissement de l’espace naturel fluvial et une incision des lits fluviaux. Les facteurs de ce processus sont le changement global dans le bassin, la construction de réservoirs d’eau et d’autres nombreuses pressions humaines directes, notamment d’extractions de graviers et de canalisations. Le delta de l’Èbre, actuel…