No description available.

No description available.

No description available.

Sixty families who came to a county mental health center for a substance abuse evaluation for a teenager were interviewed. The parent(s) and teenager were administered the Emotional Cutoff Scale, a paper-and-pencil measure. The functioning of each parent was assessed by the researcher through the Global Assessment of Functioning. The child was evaluated on the Child and Family Assessment Scale, an eight dimension scale. Data were gathered and analyzed through a correlational matrix. Significant correlations at P>.01 were found for degree of cutoff of the mother from her mother and father and her level of self-functioning but not with the level of impairment of the teenager. The sample of fathers did not result in significant correlations. / Ed. D.

O trabalho apresenta uma análise do desempenho de vários métodos de extração de fatores de intensidade de tensão a partir de soluções numéricas obtidas com o método dos elementos finitos generalizados (MEFG). A convergência dos fatores de intensidade de tensão é comparada com a da energia de deformação a fim de investigar a superconvergência dos métodos. Para extração dos fatores de intensidade de tensão e o cálculo da taxa de energia disponibilizada para propagação da fissura, implementam-se os métodos da integral de contorno (MIC), da função cutoff (MFC) e da integral-J no contexto do MEFG. Desenvolve-se a formulação dos métodos de extração de forma a obter uma implementação independente da malha utilizada na modelagem do problema. Aplica-se a extração dos fatores de intensidade de tensão, para modos puros e mistos, em problemas clássicos da mecânica da fratura. Verifica-se a convergência dos fatores de intensidade de tensão e da taxa de energia disponibilizada para a propagação da fissura, obtidos com cada método de extração, com o enriquecimento da ordem polinomial da solução do MEFG. Investiga-se a robustez dos métodos com relação ao tamanho dos domínios de extração / The performance of several techniques to extract stress intensity factors (SIF) from numerical solutions computed with the generalized finite element method (GFEM) is investigated. The convergence of the stress intensity factors is compared with the convergence of strain energy with the aim of investigate the superconvergence of the methods. The contour integral (CIM), the cutoff function (CFM) and the J-integral methods are considered to compute stress intensity factors and energy release rate. The proposed implementation of the extraction techniques is completely independent of the discretization used. Several numerical examples demonstrating the convergence of the computed stress intensity factors and the energy release rate, with the increasing of p order of the GFEM solution, are presented

O trabalho apresenta uma análise do desempenho de vários métodos de extração de fatores de intensidade de tensão a partir de soluções numéricas obtidas com o método dos elementos finitos generalizados (MEFG). A convergência dos fatores de intensidade de tensão é comparada com a da energia de deformação a fim de investigar a superconvergência dos métodos. Para extração dos fatores de intensidade de tensão e o cálculo da taxa de energia disponibilizada para propagação da fissura, implementam-se os métodos da integral de contorno (MIC), da função cutoff (MFC) e da integral-J no contexto do MEFG. Desenvolve-se a formulação dos métodos de extração de forma a obter uma implementação independente da malha utilizada na modelagem do problema. Aplica-se a extração dos fatores de intensidade de tensão, para modos puros e mistos, em problemas clássicos da mecânica da fratura. Verifica-se a convergência dos fatores de intensidade de tensão e da taxa de energia disponibilizada para a propagação da fissura, obtidos com cada método de extração, com o enriquecimento da ordem polinomial da solução do MEFG. Investiga-se a robustez dos métodos com relação ao tamanho dos domínios de extração / The performance of several techniques to extract stress intensity factors (SIF) from numerical solutions computed with the generalized finite element method (GFEM) is investigated. The convergence of the stress intensity factors is compared with the convergence of strain energy with the aim of investigate the superconvergence of the methods. The contour integral (CIM), the cutoff function (CFM) and the J-integral methods are considered to compute stress intensity factors and energy release rate. The proposed implementation of the extraction techniques is completely independent of the discretization used. Several numerical examples demonstrating the convergence of the computed stress intensity factors and the energy release rate, with the increasing of p order of the GFEM solution, are presented

Ce document rassemble les travaux effectués durant mes années de thèse. Je commence par une présentation concise des résultats principaux, puis viennent trois parties relativement indépendantes.Dans la première partie, je considère des problèmes d'inférence statistique sur un échantillon i.i.d. issu d'une loi inconnue à support dénombrable. Le premier chapitre est consacré aux propriétés de concentration du profil de l'échantillon et de la masse manquante. Il s'agit d'un travail commun avec Stéphane Boucheron et Mesrob Ohannessian. Après avoir obtenu des bornes sur les variances, nous établissons des inégalités de concentration de type Bernstein, et exhibons un vaste domaine de lois pour lesquelles le facteur de variance dans ces inégalités est tendu. Le deuxième chapitre présente un travail en cours avec Stéphane Boucheron et Elisabeth Gassiat, concernant le problème de la compression universelle adaptative d'un tel échantillon. Nous établissons des bornes sur la redondance minimax des classes enveloppes, et construisons un code quasi-adaptatif sur la collection des classes définies par une enveloppe à variation régulière. Dans la deuxième partie, je m'intéresse à des marches aléatoires sur des graphes aléatoires à degrés precrits. Je présente d'abord un résultat obtenu avec Justin Salez, établissant le phénomène de cutoff pour la marche sans rebroussement. Sous certaines hypothèses sur les degrés, nous déterminons précisément le temps de mélange, la fenêtre du cutoff, et montrons que le profil de la distance à l'équilibre converge vers la fonction de queue gaussienne. Puis je m'intéresse à la comparaison des temps de mélange de la marche simple et de la marche sans rebroussement. Enfin, la troisième partie est consacrée aux propriétés de concentration de tirages pondérés sans remise et correspond à un travail commun avec Yuval Peres et Justin Salez. / This document presents the problems I have been interested in during my PhD thesis. I begin with a concise presentation of the main results, followed by three relatively independent parts. In the first part, I consider statistical inference problems on an i.i.d. sample from an unknown distribution over a countable alphabet. The first chapter is devoted to the concentration properties of the sample's profile and of the missing mass. This is a joint work with Stéphane Boucheron and Mesrob Ohannessian. After obtaining bounds on variances, we establish Bernstein-type concentration inequalities and exhibit a vast domain of sampling distributions for which the variance factor in these inequalities is tight. The second chapter presents a work in progress with Stéphane Boucheron and Elisabeth Gassiat, on the problem of universal adaptive compression over countable alphabets. We give bounds on the minimax redundancy of envelope classes, and construct a quasi-adaptive code on the collection of classes defined by a regularly varying envelope. In the second part, I consider random walks on random graphs with prescribed degrees. I first present a result obtained with Justin Salez, establishing the cutoff phenomenon for non-backtracking random walks. Under certain degree assumptions, we precisely determine the mixing time, the cutoff window, and show that the profile of the distance to equilibrium converges to the Gaussian tail function. Then I consider the problem of comparing the mixing times of the simple and non-backtracking random walks. The third part is devoted to the concentration properties of weighted sampling without replacement and corresponds to a joint work with Yuval Peres and Justin Salez.

We describe the theory and implementation of a multipole method for calculating the modes of microstructured optical fibers (MOFs). We develop tools for exploiting results obtained through the multipole method, including a discrete Bloch transform. Using the multipole method, we study in detail the physical nature of solid core MOF modes, and establish a distinction between localized defect modes and extended modes. Defect modes, including the fundamental mode, can undergo a localization transition we identify with the mode�s cutoff. We study numerically and theoretically the cutoff of the fundamental and the second mode extensively, and establish a cutoff diagram enabling us to predict with accuracy MOF properties, even for exotic MOF geometries. We study MOF dispersion and loss properties and develop unconventional MOF designs with low losses and ultra-flattened near-zero dispersion on a wide wavelength range. Using the cutoff-diagram we explain properties of these MOF designs.

Le but de cette thèse est de relier deux phénomènes relatifs au comportement asymptotique des processus stochastiques, qui jusqu'à présent étaient restés dissociés. La convergence abrupte ou phénomène de cutoff d'une part, et la métastabilité d'autre part. Dans le cas du cutoff, une convergence abrupte vers la mesure d'équilibre du processus a lieu à un instant que l'on peut déterminer, alors que la métastabilité est liée à une grande incertitude sur l'instant où l'on va sortir d'un certain équilibre. On propose un cadre commun pour étudier et comparer les deux phénomènes : celui des chaînes de naissance et de mort à temps discret sur $\mathbb{N}$, avec une dérive vers zéro.<br />On montre que sous l'hypothèse de dérive il y a convergence abrupte vers zéro et métastabilité dans l'autre sens. De plus la dernière excursion dans la métastabilité est la renversée temporelle d'une trajectoire typique de cutoff.<br />On étend notre approche au modèle d'Ehrenfest, ce qui nous permet de montrer la convergence abrupte et la métastabilité sous une hypothèse de dérive plus faible.

In the past decade, the grouting industry has made significant technological advancements in real-time monitoring of flow rate and pressure of pumped grout, stable grout mix design, and with grout curtain concepts dealing with placement and orientation. While these practices have resulted in improved construction practices in the grouting industry, current design guidelines for grout curtains are still predominately based on qualitative measures such as engineering judgment and experience or are based on proprietary methods. This research focused on the development of quantitative guidelines to evaluate the effectiveness of a grout curtain in porous media using piezometric and hydraulic flow data. In this study, a laboratory-scale physical seepage model was developed to aid in the understanding and development methodology to evaluate the effectiveness of a grout curtain. A new performance parameter was developed based on a normalization scheme that utilized the area of the grout curtain and the area of the improved media. The normalization scheme combined with model-based Lugeon values that correspond to pore pressure and flow rate measurements at different soil unit weights and grout curtain spacings, produced a mathematical equation that can be used to quantify the effectiveness of a grout curtain. This study found a relationship that takes into account soil unit weight, grout curtain spacing and a new performance parameter that can be used to help predict the effectiveness of a grout curtain.