Search results for "Set theory"

Betweenness Centrality for Networks with Non-Overlapping Community Structure

2018

Evaluating the centrality of nodes in complex networks is one of the major research topics being explored due to its wide range of applications. Among the various measures that have been developed over the years, Betweenness centrality is one of the most popular. Indeed, it has proved to be efficient in many real-world situations. In this paper, we propose an extension of the Betweenness centrality designed for networks with nonoverlapping community structure. It is a linear combination of the so-called “local” and “global” Betweenness measures. The Local measure takes into account the influence of a node at the community level while the global measure depends only on the interactions betwe…

Improved polyhedral descriptions and exact procedures for a broad class of uncapacitated p-hub median problems

2019

Abstract This work focuses on a broad class of uncapacitated p-hub median problems that includes non-stop services and setup costs for the network structures. In order to capture both the single and the multiple allocation patterns as well as any intermediate case of interest, we consider the so-called r-allocation pattern with r denoting the maximum number of hubs a terminal can be allocated to. We start by revisiting an optimization model recently proposed for the problem. For that model, we introduce several families of valid inequalities as well as optimality cuts. Moreover, we consider a relaxation of the model that contains several sets of set packing constraints. This motivates a pol…

2018

Representative, legislative and deliberative assemblies are commonly called parliaments. The three types of assemblies share many procedures and practices, and the Inter-Parliamentary Union include...

Localization of 2D Cameras in a Known Environment Using Direct 2D-3D Registration

2014

International audience; In this paper we propose a robust and direct 2D-to- 3D registration method for localizing 2D cameras in a known 3D environment. Although the 3D environment is known, localizing the cameras remains a challenging problem that is particularly undermined by the unknown 2D-3D correspondences, outliers, scale ambiguities and occlusions. Once the cameras are localized, the Structure-from-Motion reconstruction obtained from image correspondences is refined by means of a constrained nonlinear optimization that benefits from the knowledge of the scene. We also propose a common optimization framework for both localization and refinement steps in which projection errors in one v…

El Análisis Factorial Exploratorio de los Ítems: una guía práctica, revisada y actualizada

2014

El Análisis Factorial Exploratorio es una de las técnicas más usadas en el desarrollo, validación y adaptación de instrumentos de medida psicológicos. Su uso se extendió durante los años 60 y ha ido creciendo de forma exponencial al ritmo que el avance de la informática ha permitido. Los criterios empleados en su uso, como es natural, también han evolucionado. Pero los investigadores interesados en asuntos sustantivos que utilizan rutinariamente esta técnica permanecen en muchos casos ignorantes de todo ello. En las últimas décadas numerosos trabajos han denunciado esta situación. La necesidad de actualizar los criterios clásicos para incorporar aquellos más adecuados es una necesidad urgen…

Abel transforms with low regularity with applications to X-ray tomography on spherically symmetric manifolds

2017

We study ray transforms on spherically symmetric manifolds with a piecewise $C^{1,1}$ metric. Assuming the Herglotz condition, the X-ray transform is injective on the space of $L^2$ functions on such manifolds. We also prove injectivity results for broken ray transforms (with and without periodicity) on such manifolds with a $C^{1,1}$ metric. To make these problems tractable in low regularity, we introduce and study a class of generalized Abel transforms and study their properties. This low regularity setting is relevant for geophysical applications.

Food intake affects state body image: Impact of restrained eating patterns and concerns about eating, weight and shape

2006

Body image disturbances play a significant role in the development of eating disorders. Since body image can vary in diverse contexts, the aim of the present experiment was to investigate whether it is affected by recent food intake. Fifty-seven females without clinically relevant eating disorders were randomly assigned to an experimental group (EG, n=28) that consumed a milkshake while watching a neutral film and a control group (CG, n=29) that only viewed the movie. Before and after the tasks, participants filled in the "Body Image States Scale" and the "Mood Questionnaire" and indicated their own "actual", "felt" and "ideal" body dimensions with a digital distortion technique based on a …

Psychometric properties of measures of sociocultural influence and internalization of appearance ideals across eight countries

2020

The aim of the current study was to examine the psychometric properties of two well-established measures of sociocultural influence and internalization of the thin/low body fat ideal and muscular ideal. Data from 6272 emerging adults (68.9 % female), aged 18-30 years from Australia, Belgium, Canada, China, Italy, Japan, Spain, and the U.S. were included in this study. Participants completed measures of pressure from mother, fathers, peers, and media, to both increase muscles and lose weight, as well as internalization of the thin/low body fat ideal and muscular ideal. Overall, support for partial invariance was found across the scales. In addition, group level differences were found between…

An improved method for evaluating ideal standards in self-perception and mate preferences

2014

The aim of the study was to improve the methodology for measuring ideals of self-perception and mate preferences. The Ideal Standards Model (ISM; Fletcher, Simpson, Thomas & Giles, 1999) was used as a basis for development of the scale. It was further modified by adding a number of items from previous studies. Data were collected from 223 participants, aged 19 to 27 years. The results suggested that a modified five-factor version of the ISM is an appropriate method for evaluation of ideal characteristics. The five factors are warmth/ trustworthiness, status/ resources, intelligence, social skills and physical attractiveness.

Illusory inferences from a disjunction of conditionals: a new mental models account

2000

(Johnson-Laird, P.N., & Savary, F. (1999, Illusory inferences: a novel class of erroneous deductions. Cognition, 71, 191-229.) have recently presented a mental models account, based on the so-called principle of truth, for the occurrence of inferences that are compelling but invalid. This article presents an alternative account of the illusory inferences resulting from a disjunction of conditionals. In accordance with our modified theory of mental models of the conditional, we show that the way individuals represent conditionals leads them to misinterpret the locus of the disjunction and prevents them from drawing conclusions from a false conditional, thus accounting for the compelling char…