No description available.

The aim of the present thesis is to provide an e ffective computational framework for the analysis and quantifi cation of the longitudinal structural changes in Alzheimer's disease (AD). The framework is based on the diffeomorphic non-rigid registration parameterized by stationary velocity fields (SVFs), and is hierachically developed to account for the diff erent levels of variability which characterize the longitudinal observations of T1 brain magnetic resonance images (MRIs). We developed an effi cient and robust method for the quantifi cation of the structural changes observed between pairs of MRIs. For this purpose, we propose the LCC-Demons registration framework which implements the local correlation coeffi cient as similarity metric, and we derived consistent and numerically stable measures of volume change and boundary shift for the regional assessment of the brain atrophy. In order to consistently analyze group-wise longitudinal evolutions, we then investigated the parallel transport of subject-specifi c deformation trajectories across di fferent anatomical references. Based on the SVF parametrization of diffeomorphisms, we relied on the Lie group theory to propose new and effective strategies for the parallel transport of SVFs, with particular interest into the practical application to the registration setting. These contributions are the basis for the defi nition of qualitative and quantitative analysis for the pathological evolution of AD. We proposed several analysis frameworks which addressed the di fferentiation of pathological evolutions between clinical populations, the statistically powered evaluation of regional volume changes, and the clinical diagnosis at the early/prodromal disease stages.

Objectifs : Analyser l’évolution de l’embonpoint chez les enfants québécois entre 4 et 8 ans et évaluer le rôle des différents facteurs de risque sur l’excès de poids persistant. Les données proviennent de l’étude longitudinale du développement des enfants du Québec (ÉLDEQ, 1998-2010). Cette enquête est réalisée par l’Institut de la statistique du Québec auprès d’une cohorte de 2120 nourrissons québécois nés en 1998, faisant l’objet d’un suivi annuel à partir de l’âge de 5 mois. Méthodes d’analyse : univariées, bivariées, modélisation semi-paramétrique, analyses de régressions logistique et log-linéaire (Poisson). Principaux résultats : i) L’excès de poids persistant chez les enfants âgés de 4 à 8 ans est un phénomène fluctuant, qui ne varie pas de façon significative selon le sexe ; ii) Le fait d’allaiter les enfants ne semble pas avoir un effet protecteur en ce qui concerne l’excès de poids ; iii) En ce qui concerne le poids à la naissance, les données dont on dispose ne nous permettent pas de tirer des conclusions ; iv) Le fait d’avoir une santé moins qu’excellente à la naissance semble augmenter le risque d’avoir un excès de poids persistant ; v)Ce qui influence surtout, c’est de toujours manger trop ou trop vite, ou le fait de vivre dans une famille avec un ou deux parents qui font de l’embonpoint ; vi) Les mères qui ont fume pendant leur grossesse présentent une probabilité plus élevée d’avoir des enfants avec un excès de poids persistant que celles qui n’ont pas fumé. / Objectives: Analysis of trends of overweight among children in Quebec between 4 and 8 years and evaluation of the role of various risk factors of persistent excess weight. Data: based on the Québec Longitudinal Study of Child Development (QLSCD 1998-2010). This survey is being conducted by the Institut de la statistique du Québec with a cohort of 2120 children born in Québec in 1998, being followed annually from the age of 5 months. Methods of analysis: univariate, bivariate, semi-parametric modeling, logistic and loglinear (Poisson) regression analysis. Main results: i) The persistent excess weight in children aged 4 to 8 years is a fluctuating phenomenon, which does not vary significantly by sex; ii) The act of breastfeeding children does not seem to have a protective effect with regard to children being overweight; iii) Regarding the birth weight, the available data do not allow us to draw any conclusion; iv) Having a less than excellent health at birth appears to increase the risk of persistently being overweight; v) Primary influences are always eating too much or too fast, or living in a family with one or two parents who are overweight; vi) Mothers who smoked during pregnancy are more likely to have children who are overweight than those who did not smoke.

As residential mobility recursively links individual life courses and the characteristics of places, it is unsurprising that geographers have long sought to understand how people make moving decisions. However, much of our knowledge of residential mobility processes derives from cross-sectional analyses of either mobility decision-making or moving events. Comparatively few studies have linked these separate literatures by analysing how residential (im)mobility decisions unfold over time within particular biographical, household and spatio-temporal contexts. This is problematic, as life course theories suggest that people frequently do not act in accordance with their underlying moving desires. To evaluate the extent to which residential (im)mobility is volitional or the product of constraints therefore requires a longitudinal approach linking moving desires to subsequent moving behaviour. This thesis develops this longitudinal perspective through four linked empirical studies, which each use British Household Panel Survey data to analyse how the life course context affects the expression and realisation of moving desires. The first study investigates how people make moving decisions in different ways in response to different motivations, triggers and life events. The second study harnesses the concept of ‘linked lives', exploring the extent to which the likelihood of realising a desire to move is dependent upon the desires of a person's partner. The third study analyses the biographical dimension of mobility decision-making, investigating how the long-term trajectories of life course careers are associated with particular mobility biographies. The final empirical chapter develops these insights, exploring the duration and abandonment of moving desires. Taken together, these studies test and extend conceptual models of mobility decision-making by empirically engaging with neglected facets of life course theories. Fundamentally, the thesis uncovers how aggregate mobility patterns are produced by the interactions between individual choices and multi-scalar constraints.

Mobility is central to living an independent life, to participating in society, and  to maintaining well-being in later life. The point of departure in this thesis is that retirement implies changes in time-space use and interruption in routines, which influence demands and preconditions for mobility in different ways. The aim of this thesis is to explore mobility strategies and changes in mobility upon retirement and how mobility develops during the first years of retirement. A further aim is to provide knowledge of the extent to which newly retired people maintain a desired mobility based on their needs and preconditions. The thesis is empirically based on travel diaries kept by newly retired people, and qualitative interviews with the same persons, and follow-up interviews three and a half years later. The results show that mobility is a way of forming a structure in the new everyday life as retirees by getting out of the house, either just for a walk or to do errands.  Many  patterns  of everyday life remain the same upon retirement, but the informants also merge new responsibilities and seek new social arenas and activities. As a result, the importance of   the car have not changed, but it is used for other reasons than before. After leaving paid work, new space-time constraints are created which influences demands for mobility. The study further shows that “third places” become important, especially among those who live alone, as they give an opportunity to being part of a social context and a reason for getting out of the house. The follow-up interviews revealed that declining health changes the preconditions for mobility. Daily walks had to be made shorter, and the car had to be used for most errands to where they previously could walk or cycle. However, mobility can also be maintained despite a serious illness and a long period of rehabilitation. / Mobilitet är en förutsättning för oberoende, delaktighet och välbefinnande när man åldras. Utgångspunkten i avhandlingen är att pensioneringen innebär tidsrumsliga förändringar och brott i rutiner som på olika sätt påverkar människors behov av att resa och deras förutsättningar för mobilitet. Syftet med avhandlingen är att utforska mobilitetsstrategier och förändringar i mobilitet i samband med pensioneringen samt hur mobiliteten utvecklas under de första åren som pensionär. Ambitionen är att öka kunskapen om i vilken utsträckning nya pensionärer upprätthåller en önskad mobilitet utifrån deras egna behov och förutsättningar. Avhandlingen baseras empiriskt på resedagböcker som nyblivna pensionärer har fört och kvalitativa intervjuer med samma personer, samt uppföljningsintervjuer tre och ett halvt år senare. Resultaten visar att mobiliteten är en strategi för att skapa en struktur i vardagen som pensionär genom att komma hemifrån, t.ex. för att ta en promenad eller för att uträtta ärenden. Många vardagsmönster behålls vid pensioneringen men informanterna finner också nya åtaganden och söker nya sociala arenor och aktiviteter. Betydelsen av bilen har inte förändrats men den används av andra anledningar än tidigare. Vid pensioneringen skapas andra tidsrumsliga begränsningar vilka inverkar på efterfrågan på mobilitet. Resultaten visa också att "tredje platser" blir viktiga, särskilt bland dem som lever ensamma, eftersom de ger en möjlighet att vara en del av ett socialt sammanhang och en anledning att komma hemifrån. Uppföljningsintervjuerna visade att förutsättningarna för mobilitet förändras när hälsan försämras. Promenaderna blir kortare och bilen används i högre utsträckning för de ärenden dit de tidigare kunde gå eller cykla. Men trots allvarliga sjukdomar och långa perioder av rehabilitering kan mobiliteten upprätthållas.

Cette thèse présente des méthodes d’imagerie pour l’analyse du mouvement cardiaque afin de permettre des statistiques groupées, un diagnostic automatique et une étude longitudinale. Ceci est réalisé en combinant des méthodes d’apprentissage et de modélisation statistique. En premier lieu, une méthode automatique de segmentation du myocarde est définie. Pour ce faire, nous développons une méthode de recalage très rapide basée sur des réseaux neuronaux convolutifs qui sont entrainés à apprendre le recalage cardiaque inter-sujet. Ensuite, nous intégrons cette méthode de recalage dans une pipeline de segmentation multi-atlas. Ensuite, nous améliorons des méthodes de suivi du mouvement cardiaque afin de définir des représentations à faible dimension. Deux méthodes différentes sont développées, l’une s’appuyant sur des sous-espaces barycentriques construits sur des frames de référence de la séquence et une autre basée sur une représentation d’ordre réduit du mouvement avec des transformations polyaffine. Enfin, nous appliquons la représentation précédemment définie au problème du diagnostic et de l’analyse longitudinale. Nous montrons que ces représentations en- codent des caractéristiques pertinentes permettant le diagnostic des patients atteint d’infarct et de Tétralogie de Fallot ainsi que l’analyse de l’évolution dans le temps du mouvement cardiaque des patients atteints de cardiomyopathies ou d’obésité. Ces trois axes forment un cadre pour l’étude du mouvement cardiaque de bout en bout de l’acquisition des images médicales jusqu’à leur analyse automatique afin d’améliorer la prise de décision clinique grâce à un traitement personnalisé assisté par ordinateur. / This thesis presents image-based methods for the analysis of cardiac motion to enable group-wise statistics, automatic diagnosis and longitudinal study. This is achieved by combining advanced medical image processing with machine learning methods and statistical modelling. The first axis of this work is to define an automatic method for the segmentation of the myocardium. We develop a very-fast registration method based on convolutional neural networks that is trained to learn inter-subject heart registration. Then, we embed this registration method into a multi-atlas segmentation pipeline. The second axis of this work is focused on the improvement of cardiac motion tracking methods in order to define relevant low-dimensional representations. Two different methods are developed, one relying on Barycentric Subspaces built on ref- erences frames of the sequence, and another based on a reduced order representation of the motion from polyaffine transformations. Finally, in the last axis, we apply the previously defined representation to the problem of diagnosis and longitudinal analysis. We show that these representations encode relevant features allowing the diagnosis of infarcted patients and Tetralogy of Fallot versus controls and the analysis of the evolution through time of the cardiac motion of patients with either cardiomyopathies or obesity. These three axes form an end to end framework for the study of cardiac motion starting from the acquisition of the medical images to their automatic analysis. Such a framework could be used for diagonis and therapy planning in order to improve the clinical decision making with a more personalised computer-aided medicine.

No description available.

Efforts to increase the participation of groups historically underrepresented in computing studies, and in the computing workforce, are well documented. It is a national effort with funding from a variety of sources being allocated to research in broadening participation in computing (BPC). Many of the BPC efforts are funded by the National Science Foundation (NSF) but as existing literature shows, the growth in representation of traditionally underrepresented minorities and women is not commensurate to the efforts and resources that have been directed toward this aim. Instead of attempting to tackle the barriers to increasing representation, this dissertation research tackles the underrepresentation problem by identifying what has worked (leveraging existing real-world data) to increase representation. This work studies the educational pathways of persons who have successfully transitioned into the computing workforce and identifies the common roadmaps that have contributed to retention, persistence, and success in attaining computing employment. Descriptive statistics, Logistic regression, Classification algorithms, Clustering, and Predictive analytics were employed, using the Stata statistical tool and Orange Data Mining tool on real-world data, to identify educational pathways that have resulted in successful employment outcomes for women and blacks in computing. The results of this analysis have highlighted key information that is capable of informing future “Broadening Participation in Computing” (BPC) efforts. This is because the information will enable researchers and decision makers to have a clearer picture of what educational choices have resulted in favorable outcomes for underrepresented minorities and women in computing; and consequently, researchers and decision makers would be able to more accurately target their BPC efforts to achieve optimal results. This knowledge can also be applied in career advising for young students who are trying to chart their path into computing, providing insight into alternative pathways.

Study of the critical factors for TQM implementation throughout the years, and longitudinal analysis of secondary quality winners of prestigious awards such as the Malcolm Baldrige National Quality Award (MBNQA), is important. The longitudinal analysis in this research will enable verification that there are generic critical factors (CFs) for TQM implementation and generic critical areas of measurement (CAM) that if implemented fully and successfully will deliver excellence. Also, it will enable verification that these generic CFs help to ensure sustainable performance and this could help in answering how excellent organisations sustain their performance constantly. By studying what excellent organisations measure and what they place emphasis on throughout the year, the study will document measurements that have been used to sustain excellence and will consider empirically how these have led to tangible results over a period of twenty years; the study will examine MBNQA winners from 1988 until 2008. Finally, an excellence maturity assessment tool 'assessment software' was developed as result of examining winning case studies over a long period of time, lists of critical factors of implementation (CFI) and critical areas of measurement (CAM) were extracted and used accompanied by the EFQM Excellence Model, and Zairi's two model 'Index of Excellence' and 'Ladder of Excellence'. This formed the basis of the assessment tool developed; companies through this will be able to understand their level of excellence implementation and their position compared to world class organisations.

Les études portant sur l’adéquation entre le niveau de formation des individus et celui requis pour l’emploi occupé se sont peu attardées à la dimension temporelle de cette relation. De plus, peu ont abordé la question chez les immigrants canadiens, et de surcroît chez les travailleurs immigrants sélectionnés du Québec. Une seule étude abordant le sujet sous un angle longitudinal a été recensée et se limite à l’accès des travailleurs qualifiés à un premier emploi correspondant à leur niveau de compétences. Cette thèse cherche à aller au-delà des premières transitions sur le marché du travail et vise à mieux comprendre l’évolution de la relation formation-emploi au fil du temps d’établissement. Plus spécifiquement, l’objectif y est de mieux circonscrire l’évolution de la relation formation-emploi au cours des premières années suivant l’arrivée du migrant, d’en identifier les déterminants, mais également de voir l’impact de cette relation sur d’autres dimensions de la qualité de l’emploi : le statut socioéconomique et le salaire. Afin de mieux comprendre les déterminants de l’occupation d’emplois correspondant à son niveau de compétences et d’emplois pour lesquels l’individu est suréduqué ainsi que leur impact respectif sur le statut d’emploi et le salaire, cette thèse considère l’apport de théories sociologiques et économiques. D’une part, différentes théories s’opposent quant au caractère temporaire ou permanent de la suréducation. Ce faisant, elles soulèvent l’impact potentiel des expériences en emploi passées sur le parcours futur et la nécessité d’une vision longitudinale de l’insertion professionnelle. D’autre part, d’autres approches soulèvent, en plus des déterminants individuels, le rôle du contexte social et institutionnel dans lequel l’individu s’insère. Ces différentes approches trouvent écho dans la perspective empirique du parcours de vie qui permet de considérer l’interrelation entre des facteurs micro, méso et macro sociaux et de se représenter les parcours biographiques au fil du temps. L'Enquête sur les travailleurs sélectionnés (ETS) a rendu possible l'étude des parcours en emploi de cette catégorie d'immigrant sélectionnée en fonction de son potentiel d'insertion à la société québécoise dans la mesure où celle-ci comporte à la fois des données administratives sur la situation prémigratoire des travailleurs immigrants, de même que de l'information datée sur chacun des emplois occupés après la migration. L’analyse a été effectuée en trois temps soit : une description du lien entre le niveau de formation et l’emploi, l’étude des déterminants de la relation formation-emploi et finalement, l’étude des salaires et effet de la relation formation-emploi sur ceux-ci. Chacun de ces trois volets est présenté sous forme d’articles soumis pour publication. Les résultats montrent que la proportion d’individus occupant des emplois correspondant à leur niveau de compétences augmente avec le temps passé dans la société d’accueil. Cependant, la suréducation demeure un phénomène présent chez la catégorie des travailleurs immigrants sélectionnés. À ce titre, les premières expériences en emploi sont déterminantes dans la mesure où elles ont un impact non seulement sur l’évolution de la relation formation-emploi, mais également sur les salaires et les statuts des emplois décrochés par les nouveaux arrivants. La grille de sélection, élément central du processus par lequel un candidat peut devenir immigrant au Québec, à travers les attributs des individus qu’elle retient, contribue aussi à façonner les parcours en emploi. La région de provenance des immigrants distingue également les immigrants entre eux, toutes choses égales par ailleurs. La majorité des groupes sont désavantagés lorsqu’ils sont comparés à leurs compatriotes de l’Europe de l’Ouest et des États-Unis, et ce désavantage perdure au fil des années. Cette thèse a démontré que l’insertion professionnelle et la relation formation-emploi sont des sujets se devant d’être abordés sous un angle longitudinal pour bien saisir la complexité des processus à l’œuvre. Au niveau social, les analyses auront permis de montrer l’importance de se pencher sur les services offerts aux immigrants pour les aider dans leur insertion professionnelle, surtout dans un contexte où des départs à la retraite massifs et des pénuries de main-d'œuvre qualifiée sont à prévoir. / Studies on the adequacy between the level of education of individuals and that required for the job held have rarely addressed the temporal dimension of this relationship. Moreover, few have addressed the issue among Canadian immigrants, and fewer still for skilled workers in Quebec. One study examining the subject from a longitudinal perspective has been identified, but is limited to the access of skilled workers to a first job corresponding to their skill level. This thesis seeks to go beyond the first transitions to the labour market and aims to better understand the evolution of the relationship between education and employment over the course of settlement. More specifically, the objective is to better define the progression of this relationship during the first years after the migrant’s arrival, to identify its determinants, but also to see the impact of this relationship on other dimensions of job quality: socio-economic status and salary. This thesis considers the contribution of sociological and economic theories in order to better understand the determinants of having jobs that match one’s level of skills and jobs for which the individual is over-educated, as well as their respective impacts on employment status and salary. On the one hand, various theories disagree regarding the temporary or permanent nature of over-education. In so doing, they highlight the potential impact of past job experiences on the job course and the need for a longitudinal view of labour market integration. On the other hand, other approaches underline, in addition to individual determinants, the role of the social and institutional context in which the individual belongs. These different approaches are reflected in the empirical perspective of the life course that allows us to consider the interrelationship between micro, meso and macro social factors and to represent individual histories through time. Data from the "Enquête sur les travailleurs sélectionnés" (ETS) includes both administrative data on the pre-migration situation of immigrant workers, as well as information on each job held after migration, making possible the study of pathways into employment for this immigrant category which is selected based on its potential for integration into Quebec society. The analysis was conducted in three phases, including a description of the relationship between educational attainment and employment, the study of the determinants of the education-job relationship and finally, the study of wages and the effect of the education-job relationship on them. Each of these three components is presented in the form of articles ready to be submitted for publication. The results show that the proportion of individuals in jobs that match their skill level increases with time spent in the host society. However, over-education is a phenomenon present among the skilled worker immigration category. As such, the first job experiences are critical since they have an impact not only on the evolution of the relationship between education and employment, but also on wages and the socio-economic status of jobs obtained by new immigrants. The selection grid, a central element of the process through which a candidate can become an immigrant in Quebec, also helps shape the job course through the attributes of the individuals that it retains. Region of origin distinguishes immigrants as well, all things being equal. Most groups are disadvantaged when compared to their counterparts from Western Europe and the United States, and this disadvantage persists over the years. This thesis has shown that economic integration and the education-job relationship are topics to be addressed from a longitudinal perspective in order to understand the complexity of the processes at work. At the social level, analyses have demonstrated the importance of looking at the services offered to immigrants to help them establish economically, especially in a context where retirements and massive labour shortages are expected to happen.