Search results for "MATHEMATICS"
showing 10 items of 22031 documents
An Exact Solution for the Level-Crossing Rate and the Average Duration of Fades of the Envelope of Sum-of-Cisoids Processes
2012
Authors version of an article published in the journal: Procedia Technology. Also available from the publisher at: http://dx.doi.org/10.1016/j.protcy.2012.03.004 Sum-of-cisoids (SOC) processes provide a physically and numerically appealing framework for the modelling and simulation of a wide class of mobile radio channels. This paper is concerned with the problem of finding a general solution for the level-crossing rate (LCR) and the average duration of fades (ADF) of the envelope of SOC processes. Exact expressions are derived for the LCR and the ADF by taking into account that the inphase component, the quadrature component, and the time derivatives of the inphase and quadrature component…
Ecologists overestimate the importance of predictor variables in model averaging: a plea for cautious interpretations.
2014
Abstract: Information-theory procedures are powerful tools for multimodel inference and are now standard methods in ecology. When performing model averaging on a given set of models, the importance of a predictor variable is commonly estimated by summing the weights of models where the variable appears, the so-called sum of weights (SW). However, SWs have received little methodological attention and are frequently misinterpreted. We assessed the reliability of SW by performing model selection and averaging on simulated data sets including variables strongly and weakly correlated to the response variable and a variable unrelated to the response. Our aim was to investigate how useful SWs are …
Exploring grade 9 students' assumption making when mathematizing
2015
International audience; Making assumptions is a key activity in modelling. The present study aims to explore the variety of assumptions that lower secondary students make in this process. As theoretical basis for the data analysis, we used the modelling cycle by Blum and Leiss (2007) and framed a definition of assumptions. The study was carried out with grade 9 students. The results show three categories of assumptions: (1) parameter assumptions, (2) assumptions for the choice of the mathematical model, and (3) assumptions about task expectations. Assumptions from the first two categories assist students to use extra-mathematical knowledge to construct a mathematical model, while the third …
Entornos virtuales de aprendizaje: modelo ampliado de aceptación de la tecnología
2019
Dentro de la actual renovación de las metodologías docentes, las universidades están impulsando el uso de entornos virtuales de aprendizaje como una herramienta básica en la enseñanza presencial, ya que permite flexibilizar e individualizar la educación. El objetivo del presente trabajo es aportar evidencia empírica sobre la percepción que tienen los alumnos respecto a la mejora en su aprendizaje, al adoptar y utilizar entornos virtuales en la enseñanza presencial, a partir del Modelo de Aceptación de la Tecnología ampliado. La población objeto del estudio son 251 casos de estudiantes de primer grado de la Facultad de Economía de la Universitat de Valencia. Se ha evidenciado empíricamente, …
A unifying framework for specifying generalized linear models for categorical data
2013
International audience; In the context of categorical data analysis, the case of nominal and ordinal data has been investigated in depth while the case of partially ordered data has been comparatively neglected. We first propose a new specification of generalized linear models (GLMs) for categorical response variables which en- compasses all the classical models such as multinomial logit, odds proportional or continuation ratio models but also led us to identify new GLMs. This unifying framework makes the different GLMs easier to compare and combine. We then define the more general class of partitioned conditional GLMs for categorical re- sponse variables. This new class enables to take int…
Recursion at the crossroads of sequence modeling, random trees, stochastic algorithms and martingales
2013
This monograph synthesizes several studies spanning from dynamical systems in the statistical analysis of sequences, to analysis of algorithms in random trees and discrete stochastic processes. These works find applications in various fields ranging from biological sequences to linear regression models, branching processes, through functional statistics and estimates of risk indicators for insurances. All the established results use, in one way or another, the recursive property of the structure under study, by highlighting invariants such as martingales, which are at the heart of this monograph, as tools as well as objects of study.
Analyse numérique MIGS 1re Année
2021
Il s'agit d'un cours d'analyse numérique qui a été dispensé à l'Université de Bourgogne en Master MIGS 1re Année (en 2019-2020, et 2020-2021). Il traite principalement de la résolution itérative de systèmes linéaires symétriques par gradient conjugué, et aussi de la résolution de systèmes linéaires mal posés par moindres carrés. Il vient en complément aux cours d'analyse numérique et d'optimisation que les étudiants ont suivi auparavant.
Moment Map and Gelfand Transform for the Enveloping Algebra
2019
International audience; Describing the Gelfand construction for the analytic states on an universal enveloping algebra, we characterize pure states and re-find the main result of a preceding work with L. Abdelmoula and J. Ludwig on the separation of unitary irreducible representations of a connected Lie group by their generalized moment sets.
L2 motivation in focus : the case of Finnish comprehensive school students
2017
The aim of this study is to explore whether latent classes, i.e. subgroups of students, representing specific motivational profiles can be found among learners of different foreign languages (L2s) ...
The developmental dynamics of task-avoidant behavior and math performance in kindergarten and elementary school
2012
Besides cognitive factors, children's learning at school may be influenced by more dynamic phenomena, such as motivation and achievement-related task-avoidant behavior. The present study examined the developmental dynamics of task-avoidant behavior and math performance from kindergarten to Grade 4. A total of 225 children were tested for their arithmetic skills in kindergarten and in Grades 1, 2, and 4 of elementary school. Children's task-avoidant behavior in learning situations was rated by their teachers. The results of latent growth curve analyses showed that math performance and task-avoidant behavior develop in tandem: an increase in task-avoidant behavior was related to less improvem…