Search results for "statistical [Methods]"

Centile estimation for a proportion response variable.

2015

This paper introduces two general models for computing centiles when the response variable Y can take values between 0 and 1, inclusive of 0 or 1. The models developed are more flexible alternatives to the beta inflated distribution. The first proposed model employs a flexible four parameter logit skew Student t (logitSST) distribution to model the response variable Y on the unit interval (0, 1), excluding 0 and 1. This model is then extended to the inflated logitSST distribution for Y on the unit interval, including 1. The second model developed in this paper is a generalised Tobit model for Y on the unit interval, including 1. Applying these two models to (1-Y) rather than Y enables model…

Autocatalytic reaction-diffusion processes in restricted geometries

2008

We study the dynamics of a system made up of particles of two different species undergoing irreversible quadratic autocatalytic reactions: $A + B \to 2A$. We especially focus on the reaction velocity and on the average time at which the system achieves its inert state. By means of both analytical and numerical methods, we are also able to highlight the role of topology in the temporal evolution of the system.

SURCOTES MARINES DANS LE GOLFE DU LION ET FORCAGES ATMOSPHERIQUES : VARIABILITE CONTEMPORAINE ET FUTURE (1950-2100)

2010

Sea surges in the Gulf of Lions are mainly forced by southerly and south-easterly winds. This regional-scale atmospheric circulation is leading by a strong zonal gradient between low pressure system over the Bay of Biscay and high pressure over central Europe. This synoptic-scale circulation mostly happens during “Greenland Above” weather regime. In the second half of the 20th century, a slow increase of the sea-level pressure over central Europe increased the probability of having “Greenland Above” weather types associated with a southerly atmospheric circulation in the Gulf of Lions, thus leading to strong surges. A linear regression is used to simulate the interannual variability of high…

Proceedings of 28th International Workshop on Statistical Modelling, volume 2

2013

Proceedings of the 28th International Workshop on Statistical Modelling, volume 1

2013

Fallacies about p-Value Shared by Professors and University Students

2017

Resumen La “Práctica Basada en la Evidencia” requiere a los profesionales valorar de forma crítica los resultados de las investigaciones psicológicas. Sin embargo, las interpretaciones incorrectas de los valores p de probabilidad son abundantes y repetitivas. Estas interpretaciones incorrectas pueden afectar las decisiones profesionales y poner en riesgo la calidad de las intervenciones y la acumulación de un conocimiento científico válido. Por lo tanto, identificar el tipo de falacia que subyace a las decisiones estadísticas es fundamental para abordar y planificar estrategias de educación estadística dirigidas a intervenir sobre las interpretaciones incorrectas. En consecuencia, el objeti…

DAE-GP

2020

Estimation of distribution genetic programming (EDA-GP) algorithms are metaheuristics where sampling new solutions from a learned probabilistic model replaces the standard mutation and recombination operators of genetic programming (GP). This paper presents DAE-GP, a new EDA-GP which uses denoising autoencoder long short-term memory networks (DAE-LSTMs) as probabilistic model. DAE-LSTMs are artificial neural networks that first learn the properties of a parent population by mapping promising candidate solutions to a latent space and reconstructing the candidate solutions from the latent space. The trained model is then used to sample new offspring solutions. We show on a generalization of t…

Influence of geometric variations on LV activation times: A study on an atlas-based virtual population

2010

We present the fully automated pipeline we have developed to obtain electrophysiological simulations of the heart on a large atlas-based virtual population. This virtual population was generated from a statistical model of left ventricular geometry, represented by a surface model. Correspondence between tetrahedralized volumetric meshes was obtained using Thin Plate Spline warps. Simulations are based on the fast solving of Eikonal equations, and stimulation sites correspond to physiological activation. We report variations of total activation time introduced by geometry, as well as variations in the location of last activation. The obtained results suggest that the total activation time ha…

Nonlinear Relaxation in Population Dynamics

2001

We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical properties of the asymptotic behaviour of the time integral of the i-th population and on the distribution of the population and of the local field.

Providing insights into browntail moth local outbreaks by combining life table data and semi-parametric statistics

2011

1. Life table studies have been an essential tool for the comprehension of insect population dynamics, although their use has been methodologically biased by a primary focus on mortality factors, especially natural enemies. Thus, studies in natural populations may relegate important mortality sources to the ‘unknown’ or ‘residual’ mortality categories. To overcome this limitation, life tables may be complemented by combining them with other approaches. 2. The aim of the present study was to provide insights into browntail moth Euproctis chrysorrhoea L. (Lepidoptera: Lymantriidae) local outbreaks by combining life table data and statistical modelling. First, E. chrysorrhoea population densit…