McGill University Theses and dissertations published in 2013

Modern information systems, consisting of an application server tier and a database tier, offer several consistency guarantees for accessing data where strong consistency is traded for better performance or higher availability. However, it is often not clear how an application is affected when it runs under a low level of consistency. In fact, current application designers have basically no tools that would help them to get a feeling of which and how many inconsistencies actually occur during run-time of their particular application. In this thesis, we present new approaches to detect and quantify consistency anomalies for arbitrary multi-tier or cloud …  Read more

High Frequency Oscillations (HFOs; 80-500Hz) are spontaneous short-duration small-amplitude EEG patterns that are emerging as a biomarker of tissue capable of generating epileptic seizures. In order to propel the clinical utilization and systematic study of HFOs, it is important to develop robust automatic detectors and to provide a framework to ensure stability in their identification; this is the first goal of this thesis. Although HFOs have mostly been studied with intracranial electrodes, they have also been recorded on the scalp. A fundamental question is to understand how is it possible to see these small events on the scalp given the …  Read more

The present study adopted Seymour and Dargie's design (1990) and examined the associative priming effect on English non-word spelling in young ESL learners with Chinese language backgrounds. Participants were either assigned to an unprimed non-word dictation condition or a primed condition where the non-word was preceded by a prime which is semantically associated to a word that rhymed with the target non-word. The orthographical choice of vowel pattern in the non-word dictation task for young ESL learners greatly depends on its contingency. The results in the present study indicated that the children with higher reading proficiency were more sensitive to …  Read more

This thesis makes contributions to the statistical analysis of causality and volatility in econometrics. It consists of five essays, theoretical and empirical. In the first one, we study how to characterize and measure multi-horizon second-order causality. The second and third essays propose linear estimation methods for univariate and multivariate weak GARCH models. In the fourth essay, we use multi-horizon causality measures to study the causal relationships between commodity prices and exchange rates with high-frequency data. In the fifth essay, we evaluate the historical evolution of volatility forecast skill.Given the increasingly important role of volatility forecasting in financial studies, a number …  Read more

Using a fracture mechanics framework, we present a finite element method to simulate the break-up of 2D ice accreted on the wings of aircraft and the shedding of 3D ice accreted on blades of helicopter. The fully automated ice break-up module is integrated in FENSAP-ICE [1-2], which is an in-flight ice accretion simulation code that solves flow, droplet impingement and ice accretion, in sequence. The 2D and 3D crack propagation packages are developed and validated by comparing with published results for a single edge cracked plate test case and a single edge-notched specimen with three points bending load, respectively. Numerous …  Read more

The eukaryotic cell cytoskeleton plays many important roles in cells and their coordination is crucial for these important biological processes. Their functions are partially achieved by the actin-microtubule (MT) cross-linking proteins. Growth-arrest-specific (Gas) 2 was originally identified in murine fibroblasts under growth-arrest conditions. Gas2 protein contains putative actin- and MT-binding domains, which makes it a strong candidate to be an actin-MT cross-linking protein. However, the mechanisms of Gas2 cytoskeleton binding and its roles in cell division are still unclear. This thesis is focused on these questions. In Chapter 2, we have determined the Gas2 protein functions in Xenopus laevis embryo …  Read more

After decades of development, the wind energy industry is now supplying 10 to 20% of power in electric utilities. At present Doubly-Fed Induction Generators (DFIG) are one of the most widely used generators in wind farms. The research of this thesis advances the methods of controlling DFIGs by presenting: (i)a non-mechanical (sensorless) method of determining accurate rotor speed and rotor position which are essential in implementing decoupled P-Q control; (ii)a method of autonomous frequency control whereby an islanded wind farm does not have to shut down but continues to operate as standby ready to assist the utility grid in fast …  Read more

Chodavarapu, Vamsy (Supervisor2)  Read more

Les nanofils semi-conducteurs sans dislocations sont une voie très prometteuse vers l'intégration des semi-conducteurs composés avec la technologie silicium. Cependant, un contrôle précis de dopage des nanofils, ainsi que les propriétés de charge de surface, reste un défi universel à ce jour. À cet égard, nous avons étudié la croissance épitaxiale par faisceau moléculaire et les propriétés de surface corrélés électriques et optiques des nanofils de InN sur du substrat de silicium, qui ont émergé comme candidat prometteur pour l'avenir des dispositifs électroniques et photoniques à très haute vitesse et à échelle nanométriques.Pour la première fois, en améliorant le processus …  Read more

Les cellules régulatrices T (Treg) sont importantes pour la maintenance de la tolérance et de l'homéostasie immunitaires. Des analyses pan-génomiques ont précédemment permis d'établir les signatures transcriptionnelles distinguant les cellules Treg des cellules effectrices T (Teff). Toutefois, de nombreuses études montrent que les changements dans les niveaux d'ARN messager totaux ne correspondent pas toujours avec les niveaux des protéines à cause de la régulation post-transcriptionnelle. Notre laboratoire a récemment effectué la première analyse pan-génomique du contrôle traductionnel de l'expression des gènes dans les sous-populations des cellules T CD4 primaires, montrant que la traduction du facteur d'initiation eucaryote 4E (eIF4E) est …  Read more

Cette étude porte sur l'utilisation de Géospatiales Web 2.0 et Modèle Climatique Global pour le communication du changement climatique. Le but de cette recherche a été d'intégrer les données, les modèles et les outils de la science du climat avec Geoweb pour faire progresser la communication du changement climatique. Plusieurs applications de GeoWeb ont été développés pour démontrer les solutions de cette intégration et de remplir deux objectifs de recherche: (1) développer une méthode d' utiliser les technologies GeoWeb pour communiquer du changement climatique, (2) améliorer l'accessibilité de Modèle Climatique Global en fournissant des outils pour engager personnes dans la …  Read more

Shih, Ishiang (Internal/Cosupervisor2)  Read more

The academic success of students depends, among several factors, on the school's learning environment and the teacher's classroom management skills. In recent years creative solutions to curb poor behavior by establishing proper class discipline have come to the forefront of the teaching profession. With that in mind, the present research topic was chosen to foster appropriate student conduct in establishing and sustaining a productive learning environment through the use of the Positive Behavior Support model. This teacher-as-researcher study took place over a one-year period (2010-2011) in a secondary two class of twenty-five students at a Quebec high school. The collection …  Read more

Ore dilution has an important influence on mining costs and hence on the viability of a mining operation. Costs associated with ore dilution with barren waste or material below the cut-off grade are linked to all mining and milling stages. Several research efforts were made in the past to help better understand the causes of ore dilution, and some of these led to the development of empirical formulae for the estimation of ore dilution in different mining environments. Stope geometry was identified as one of the principal factors influencing ore dilution attributed to stope wall overbreak. This thesis examines the …  Read more

Peter Chan (Supervisor2)  Read more

L'estimation de la pose et du torseur cinématique des corps rigides est un problème qui se retrouve partout en science et en ingénierie, aussi bien en aérospatiale, aéronautique ou biomécanique que dans les systèmes de navigation ou les jeux vidéos. La technologie acutelle repose principalement sur les assemblages d'accéléromètres qui exigent des algorithms d'estimation précis. Le principal objectif de cette thèse est donc de développer des accéléromètres innovateures capables d'estimer, avec exactitude et fiabilité, la situation et le torseur cinématique en question. La conception de ces accéléromètres s'appuie sur deux idées originales interdépendantes: la biaxialité des accéléromètres, présentés antérieurement dans …  Read more

Le diabète de type 1 (DT1) est une maladie auto-immune où les cellules bêta, productrices de l'insuline, sont détruites par le système immunitaire. Cette maladie dont l'étiologie est complexe, implique à la fois des facteurs génétiques et environnementaux. Plus de 40 loci génétiques, où il y a une association avec la variation allélique de plusieurs polymorphismes, ont été montré comme augmentant le risque de DT1. Deux de ces régions les plus importantes sont localisés dans la région chromosomique 2q24.3, qui contient des polymorphismes fonctionnels au niveau du gène IFIH1 dont le rôle est de lier l'ARN double brin (DS) viral …  Read more

Tuberculosis (TB) continues to pose a global health threat, and was responsible for 1.4 million deaths worldwide in 2010.1 Health care workers (HCWs) are at risk of TB exposure, infection and disease. Effective screening of HCWs for latent TB infection (LTBI) is a critical element of TB control programs in Canada and elsewhere, and requires accurate and reliable tests to diagnose and predict progression to active disease. Recently, novel blood-based assays called interferon-gamma release assays (IGRAs) have been introduced for the diagnosis of LTBI, as an alternative to the tuberculin skin test (TST). IGRAs offer many advantages over the TST, …  Read more

The gut microbiota is a personalized organ and body weight fluctuations affect the innate ratio of bacterial phyla in the microbiome (Bacteroidetes and Firmicutes) thereby modifying nutrient extraction capability (143, 146). Weight gain inversely influences the ratio resulting in increased energy harvest efficiency, subsequently increasing weight gain leading to obesity (143). As a leading public health concern in industrialized nations, it is imperative to understand the role of the microbiota in relation to obesity. Furthermore, imbalance or damage to the microbiota by bile acid malabsorption has been implicated in the etiology of gastrointestinal disorders such as irritable bowel syndrome and …  Read more