Search results for " selection"

Ethics of uterus transplantation with live donors.

2014

An Improved Decision System for URL Accesses Based on a Rough Feature Selection Technique

2015

Corporate security is usually one of the matters in which companies invest more resources, since the loss of information directly translates into monetary losses. Security issues might have an origin in external attacks or internal security failures, but an important part of the security breaches is related to the lack of awareness that the employees have with regard to the use of the Web. In this work we have focused on the latter problem, describing the improvements to a system able to detect anomalous and potentially insecure situations that could be dangerous for a company. This system was initially conceived as a better alternative to what are known as black/white lists. These lists co…

Predator Mixes and the Conspicuousness of Aposematic Signals

2003

Conspicuous warning signals of unprofitable prey are a defense against visually hunting predators. They work because predators learn to associate unprofitability with bright coloration and because strong signals are detectable and memorable. However, many species that can be considered defended are not very conspicuous; they have weak warning signals. This phenomenon has previously been ignored in models and experiments. In addition, there is significant within- and among-species variation among predators in their search behavior, in their visual, cognitive, and learning abilities, and in their resistance to defenses. In this article we explore the effects of variable predators on models th…

A global model for the estimation of transport costs

2019

This paper presents a model of transport cost determinants that corrects the specification problems observed in the transport cost equations in previous literature. The model includes freight transport supply and demand, as well as infrastructure quality and non-time-varying fixed effects related to the route, the exporting company, its strategy and the product. In addition, when defining the origin-destination routes, the model more appropriately accounts for economies of network and economies of scale. In order to build the database, 583 personal interviews were conducted over the course of 2011 with producing companies that ship goods and with the logistics operators. As a result, 305 ro…

The continuous sample of working lives: Improving its representativeness

2017

This paper studies the representativeness of the Continuous Sample of Working Lives (CSWL), a set of anonymized microdata containing information on individuals from Spanish Social Security records. We examine several CSWL waves (2005–2013) and show that it is not representative for the population with a pension income. We then develop a methodology to draw a large dataset from the CSWL that is much more representative of the retired population in terms of pension type, gender and age. This procedure also makes it possible for users to choose between goodness of fit and subsample size. In order to illustrate the practical significance of our methodology, the paper also contains an applicatio…

Nature et impacts des effets spatiaux sur les valeurs immobilières : le cas de l'espace urbanisé francilien

2013

International audience

La selezione dei giudici della Corte di giustizia. Poteri e limiti del comitato ex. art. 255 TFUE

2013

Abstract The appointment of judges to supranational and international courts has long been an unstudied area of sovereign activity. However, the growing role and significance of the European Court of Justice (ECJ), by now one of the most significant players within the European political and constitutional space, demands reforms which also affect its architecture. The creation of the advisory panel under article 255 TFUE, is a way to improve judicial independence and proficiency but also a mean to achieve an adequate level of judicial accountability. Indeed, the existing national nomination processes, missing both transparency and public involvement, risk to shape courts which are far away t…

Applying differential geometric LARS algorithm to ultra-high dimensional feature space

2009

Variable selection is fundamental in high-dimensional statistical modeling. Many techniques to select relevant variables in generalized linear models are based on a penalized likelihood approach. In a recent paper, Fan and Lv (2008) proposed a sure independent screening (SIS) method to select relevant variables in a linear regression model defined on a ultrahigh dimensional feature space. Aim of this paper is to define a generalization of the SIS method for generalized linear models based on a differential geometric approach.

Induced smoothing in LASSO regression

The thesis is being carried out with the National research Council at the Institute of Biomedicine and Molecular Immunology "Alberto Monroy" of Palermo, where I am a fellow, under the supervision of MD Stefania La Grutta. Our research unit is focused on clinical research in allergic respiratory problems in children. In particular, we are interested in to assess the determinants of impaired lung function in a sample of outpatient asthmatic children aged between 5 and 17 years enrolled from 2011 to 2017. Our dataset is composed by n = 529 children and several covariates regarding host and environmental factors. This thesis focuses on hypothesis testing in lasso regression, when one is interes…

European traditional tomatoes galore: a result of farmers' selection of a few diversity-rich loci

2022

A comprehensive collection of 1254 tomato accessions, corresponding to European traditional and modern varieties, early domesticated varieties, and wild relatives, was analyzed by genotyping by sequencing. A continuous genetic gradient between the traditional and modern varieties was observed. European traditional tomatoes displayed very low genetic diversity, with only 298 polymorphic loci (95% threshold) out of 64 943 total variants. European traditional tomatoes could be classified into several genetic groups. Two main clusters consisting of Spanish and Italian accessions showed higher genetic diversity than the remaining varieties, suggesting that these regions might be independent seco…