VictorJuiz/thesis huggingface dataset:
Measuring Slip Resistance of Winter Footwear

Slip and fall accidents represent an enormous burden in terms of human suffering and economic costs. In winter conditions, outdoor falls increase as cold temperatures and precipitation create hazardous conditions underfoot. An effective method of reducing falls is the use of slip resistant footwear. However, the optimization of this footwear is hindered by the fact that slip resistance is not easily measured and the validity of existing measurement devices is questionable. The series of four studies presented here show the progression of work utilizing human-centred approaches to evaluating the performance of winter footwear on real winter surfaces and have led to the development of a new test method. To start, traditional measures of slip severity were used to evaluate the effectiveness of winter boots and cleated footwear devices while subjects walked in common winter conditions. Walking trials on level and uneven icy surfaces showed that while cleated footwear did reduce slip frequency, they did not prevent dangerous slips from occurring. Further testing showed that the current standard test conditions and parameters used for determining footwear slip resistance do not adequately simulate gait in winter conditions. As a result, a new user-centred protocol was developed for testing footwear. Subjects were asked to stand and walk across a wet, icy surface that was tilted progressively until they could no longer maintain balance, thereby establishing the maximum achievable incline angle for a variety of styles of footwear. This method proved to be reliable on wet ice so a refined protocol was applied to a larger sample of footwear which was then tested on dry ice as well as snow conditions. The results showed the importance of testing winter footwear in snow conditions, which had not been done before. These studies demonstrate the viability of testing footwear without removing the critically important human component.

Keywords: Footwear
Friction
Gait
Slip Resistance
Slips and Falls
Advisor: Fernie, Geoff R
RST-style Discourse Parsing and Its Applications in Discourse Analysis

Discourse parsing is the task of identifying the relatedness and the particular discourse relations among various discourse units in a text. In particular, among various theoretical frameworks of discourse parsing, I am interested in Rhetorical Structure Theory (RST). I hypothesize that, given its ultimate success, discourse parsing can provide a general solution for use in many downstream applications.This thesis is composed of two major parts. First, I overview my work on discourse segmentation and discourse tree-building, which are the two primary components of RST-style discourse parsing. Evaluated on the RST Discourse Treebank (RST-DT), both of my discourse segmenter and tree-builder achieve the state-of-the-art performance.Later, I discuss the application of discourse relations to some specific tasks in the analysis of discourse, including the evaluation of coherence, the identification of authorship, and the detection of deception. In particular, I propose to use a set of application-neutral features, which are derived from the discourse relations extracted by my discourse parser, and compare the performance of these application-neutral features against the classic application-specific approaches to each of these tasks. On the first two tasks, experimental results show that discourse relation features by themselves often perform as well as those classic application-specific features, and the combination of these two kinds of features usually yields further improvement. These results provide strong evidence for my hypothesis that discourse parsing is able to provide a general solution for the analysis of discourse. However, we failed to observe a similar effectiveness of discourse parsing on the third task, the detection of deception. I postulate that this might be due to several confounding factors of the task itself.

Keywords: Computational Linguistics
Discourse Analysis
Discourse Parsing
Advisor: Hirst, Graeme
Declines and Regains in Income Status and Health Status Among Mid- and Later-life Canadians

As Canada's population ages, understanding the associated economic and social issues that may emerge becomes critical. This study's purpose was to investigate sociodemographic and health behaviour factors that influence income and/or health changes among Canadians in mid- and later-life. To examine these factors, logistic regression analyses were undertaken using a representative sample (n = 2,368) of Canadians, ages 40 to 59 from seven cycles (1994-1995 to 2006-2007) of longitudinal data from the National Population Health Survey. This study examined whether, for this age group, income decline was a stronger determinant of health decline (social causation) than vice versa (reverse causation). Of 382 respondents who experienced both an income and health decline, 230 experienced an income before a health decline. Several logistic regression findings supported social causation and only one supported reverse causation. Also explored by this study was the comparative influence of sociodemographic versus health behaviour factors on changes in income and health. Compared to sociodemographic factors, health behaviour factors had less influence on changes in income and health. The physical inactivity and obesity variables were infrequently statistically significant predictors of income and health changes. The drinking habits variable was frequently a statistically significant predictor of changes in income and health. A history of smoking was very frequently a statistically significant predictor--of health declines only, both income and health declines, and income declines before health declines.The factors associated with * two-fold declines (income and health) were higher income, good or very good (vs. excellent) health, being older, not having graduated from high school, and a history of smoking; * income regains were lower income, being male, younger, married, and a high school graduate; and * health regains were higher income, being neither a high school graduate nor an immigrant, never having smoked, and being a moderate or nondrinker. A better understanding of the patterns and predictors of income and health declines and regains among mid- and later-life Canadians may serve to identify opportunities to improve the future welfare of the elderly.

Keywords: Canada
logistic regression analyses
mid- and later-life
National Population Health Survey
social causation
sociodemographic and health behaviour factors
Advisor: McDonald, Lynn
Flexible Dynamics and Attitude Control of a Square Solar Sail

This thesis presents a comprehensive analysis of attitude and structural dynamics of a square solar sail. In particular, this research examines the use of corner-attached reflective vanes to control the attitude of the spacecraft. An introduction to known solar sail designs is given, then the mathematics involved in calculating solar radiation pressure forces are presented. A detailed derivation and implementation of the unconstrained nonlinear flexible structural dynamics with Finite Element Method (FEM) models are explored, with several sample simulations of published large deflection experiments used as verification measures. To simulate the inability of a thin membrane to resist compression, the sail membrane elements are augmented with a method that approximates the wrinkling and the slacking dynamics, which is followed by a simulation of another well-known experiment as a verification measure.Once the structural dynamics are established, the usage of the tip vanes is explored. Specifically, a control allocation problem formed by having two degrees of freedom for each tip vane is defined and an efficient solution to this problem is presented, allowing desired control torques to be converted to appropriate vane angles. A randomized testing mechanism is implemented to show the efficacy of this algorithm. The sail shadowing problem is explored as well, where a component of the spacecraft casts shadow upon the sail and prevents solar radiation pressure force from being produced. A method to calculate the region of shadow is presented, and two different shadowing examples are examined - due to the spacecraft bus, and due to the sail itself.Combining all of the above, an attitude control simulation of the sail model is presented. A simple PD controller combined with the control allocation scheme is used to provide the control torque for the sail, with which the spacecraft must orient towards a number of pre-specified attitude targets. Several attitude orientations are simulated, then a number of modifications to the control are explored. The controllability of the rigid and the elastic modes of the sail at different stable states is demonstrated as well, showing that the sail is controllable for all its modes in its stable state.

Keywords: Attitude Control
Control Allocation
Finite Element Method
Flexible Dynamics
Solar Sail
Wrinkling
Advisor: Damaren, Christopher J.
Study of the Regulation of the Expression of the Notch Ligand Delta-like 4 by Thymic Epithelial Cells

The thymus is the inductive site for T-cell lymphopoiesis. Key to this function is the expression of the Notch ligand Delta-like 4 (Dll4) on the surface of thymic epithelial cells (TECs). Work by our laboratory and others have linked the control of Dll4 expression to the 3-dimensional (3D) reticular arrangement of TECs and implicated that the transcription factor FoxN1 as playing a role in the regulatory axis. However, a full understanding of Dll4 regulation remains elusive. In this thesis, evidence is put forth which supports the model in which Dll4 is regulated both at the transcriptional and post-transcriptional level. Transcriptionally, FoxN1 is a direct regulator of Dll4 transcriptional initiation, as there are functional FoxN1 consensus sequences in the the promoter region of Dll4. Furthermore, ectopic FoxN1 expression can increase levels of Dll4 messenger RNA (mRNA) in thymic stromal monolayer cell cultures. Post-transcriptionally, Dll4 mRNA contains destabilizing AU-rich elements in its 3' untranslated region. The 3D reticular arrangement of TECs contributes to stabilize Dll4 mRNA likely as a result of active p38 mitogen activated protein kinase (MAPK) signalling. Upon disruption of the 3D structure, p38 MAPK signalling is diminished, concomitant with a rapid decay of Dll4, while pharmacological activation of the p38 MAPK pathway blunts the loss of Dll4 expression in monolayer TEC cultures. Future studies will focus on identifying the physiologically relevant extracellular signalling cues that activate p38 MAPK in TECs, and describing the factors contributing to the decay and stability of Dll4 mRNA. By understanding Dll4 regulation, we will gain insight not only into the biology of the thymus, but how organ structure affects gene function at the molecular level.

Keywords: Delta-like 4
Gene expression
mRNA regulation
Thymic epithelial cells
Thymus
Advisor: Zúñiga-Pflücker, Juan Carlos
How District System Leaders Support Principal Capacity Building in Ontario: A Study of the Leading Student Acheivement Initiative

This thesis examines how district leaders, specifically Leading Student Achievement (LSA) System Leaders, support principal capacity building in the Ontario Leading Student Achievement project. The LSA project uses the strategy of networked principal capacity building to support the interaction of principals within and across schools to build professional knowledge creation and sharing. The conceptual framework for this study is based on the research on district practices that influence improved student learning. This study identifies how LSA System Leaders support networked principal capacity building through an examination of Ministry of Education expectations for LSA System Leaders; board contextual factors that influence how LSA System Leaders support networked principal capacity building; LSA System Leader personal experiences; and the use of LSA online networked learning formats. Phone interviews of a sample of LSA System Leaders confirmed their use of Ontario Leadership Framework (OLF) practices in supporting networked principal capacity building. Respondents provided evidence of how they act as implementing agents, aligning the LSA initiative with other board and Ministry of Education initiatives. During 2012-2013, LSA System Leaders noted the impact of labour unrest on their ability to collect and utilize system student achievement data to focus networked principal capacity building. The study findings confirmed the presence of resolute leadership within the guiding coalition in board committees to improve student achievement, as well as in senior administration. The study findings also confirmed that district leaders' practices to support principal capacity building evolve, respond and adapt to board and school contextual factors, and evolving principal learning needs. District leaders facilitated access to online learning formats to maximize capacity building through pre and post-session learning activities. The study findings were situated within the broader literature review to address the role of districts in supporting professional learning; the nature of district practices which support professional learning; and implications for districts leading networked principal capacity building. A further synthesis of the study findings classified district leader practices to support principal capacity building as those of focusing and aligning; resourcing and incentivizing; and using personal leadership resources

Keywords: District Leaders
Leadership
Leading Student Achievement
Advisor: Campbell, Carol
Autonomous Soaring and Surveillance in Wind Fields with an Unmanned Aerial Vehicle

Small unmanned aerial vehicles (UAVs) play an active role in developing a low-cost, low-altitude autonomous aerial surveillance platform. The success of the applications needs to address the challenge of limited on-board power plant that limits the endurance performance in surveillance mission. This thesis studies the mechanics of soaring flight, observed in nature where birds utilize various wind patterns to stay airborne without flapping their wings, and investigates its application to small UAVs in their surveillance missions. In a proposed integrated framework of soaring and surveillance, a bird-mimicking soaring maneuver extracts energy from surrounding wind environment that improves surveillance performance in terms of flight endurance, while the surveillance task not only covers the target area, but also detects energy sources within the area to allow for potential soaring flight. The interaction of soaring and surveillance further enables novel energy based, coverage optimal path planning. Two soaring and associated surveillance strategies are explored. In a so-called static soaring surveillance, the UAV identifies spatially-distributed thermal updrafts for soaring, while incremental surveillance is achieved through gliding flight to visit concentric expanding regions. A Gaussian-process-regression-based algorithm is developed to achieve computationally-efficient and smooth updraft estimation. In a so-called dynamic soaring surveillance, the UAV performs one cycle of dynamic soaring to harvest energy from the horizontal wind gradient to complete one surveillance task by visiting from one target to the next one. A Dubins-path-based trajectory planning approach is proposed to maximize wind energy extraction and ensure smooth transition between surveillance tasks. Finally, a nonlinear trajectory tracking controller is designed for a full six-degree-of-freedom nonlinear UAV dynamics model and extensive simulations are carried to demonstrate the effectiveness of the proposed soaring and surveillance strategies.

Advisor: Liu, Hugh H.T.
Structural and Functional Correlates of Hand Recovery Following Childhood Stroke

Following stroke in children, there is a wide range of motor recovery. This study examined the role of the corticospinal tract (CST) and its association with motor outcome of the hand in children following arterial ischemic stroke (AIS). The corticospinal tract was assessed several ways, using the appropriate imaging modalities.The primary hypothesis was that the extent of motor recovery in the stroke affected hand would be associated with two factors: 1) the extent of anatomical damage to the stroke affected corticospinal tract, and, 2) the extent and pattern of functional reorganization within the motor system. Children with AIS in the middle cerebral artery territory, occurring after the age of 2, were assessed for motor function with the validated Pediatric Stroke Outcome Measure. The presence of corticospinal tract damage was determined using conventional MRI to assess Wallerian degeneration, and diffusion tensor imaging (DTI) to quantify damage at the microstructural level. These measures were done in chronic phase following stroke. In the acute phase, (1 - 10 days post stroke), the presence of diffusion weighted imaging (DWI) signal abnormalities in the corticospinal tract were determined. Finally, neural activation patterns were evaluated using functional MRI to assess the location and extent of functional reorganization of the hand following stroke. These activation patterns were also assessed to determine the association with corticospinal tract integrity, and motor outcome. We found the integrity of the CST shows an association with motor outcome of the hand in pediatric stroke patients. Greater damage to the CST was associated with a greater motor deficit, suggesting that the level of motor skill recovery achieved in pediatric stroke patients relates to the gross morphological, and microstructural status of the CST. Integrity of the fibers in the CST also showed an association with the brain activation patterns. Greater damage to the CST was associated with a larger volume of activations during stroke affected hand use in the stroke affected hemisphere, and more severe outcome. The current study suggests that a structural and functional relationship exists in children with variable recovery of hand function following stroke. The use of complementary imaging techniques was effective in evaluating this relationship.

Keywords: Functional Imaging
Medical Imaging
Motor Recovery
Pediatrics
Plasticity
Stroke
Advisor: deVeber, Gabrielle
Defining the Role of Pds5 in the Maintenance of Sister Chromatid Cohesion

The establishment, maintenance and dissolution of sister chromatid cohesion are sequentially coordinated during the cell cycle to ensure faithful chromosome transmission. This cell cycle-dependent regulation of cohesion is mediated, in part, by distinct post-translational modifications of cohesin, a protein complex consisting of the Smc1-Smc3 ATPase, the Mcd1/Scc1 kleisin and Scc3. Although cohesion is established in S phase, cohesins are not sufficient to maintain cohesion as cells progress from G2 to the metaphase-to-anaphase transition. Rather, the cohesin-associated factor, Pds5, is also required to keep sisters paired until anaphase onset. How Pds5 maintains cohesion at the molecular level and whether this maintenance involves the regulation of cohesin modifications remains to be defined. In this thesis, I show that, in pds5 mutants, Mcd1 is extensively SUMOylated and that premature sister separation requires Siz2-dependent polySUMOylation. Moreover, I show that abrogation of Pds5 function promotes the proteasome-dependent degradation of Mcd1 and a significant loss of cohesin from chromatin independently of anaphase onset. I further demonstrate that inactivation of the Slx5-Slx8 SUMO-Targeted Ubiquitin Ligase, required for targeting polySUMOylated factors for proteasome-mediated destruction, limits Mcd1 turnover and restores both cell growth and cohesion in metaphase cells defective for Pds5 function. I propose that Pds5 maintains cohesion, at least in part, by antagonizing the polySUMO-dependent degradation of cohesin and further discuss the implications of such a mechanism in the regulation of dynamic chromosome-related processes, both within and beyond the context of sister chromatid cohesion.

Advisor: Lavoie, Brigitte D
Injection-molded Thermoplastic Foams for Sound Insulation

Open-cell foam materials have many applications such as sound and thermal insulators, filter and separation membranes, scaffolds, battery electrode supports, and printing heads. Commercial open-cell polymeric foams have been almost exclusively manufactured with polyurethane thermoset materials. While the production of thermoplastic open-cell foam has been studied in batch foaming and extrusion systems, open-cell foaming with the injection molding process has not received enough attention due to its inherent challenge to produce an open-cell structure. However, despite that challenge, injection molding is one of the most cost-effective and widely used polymer processing technologies. Thermoplastic polymeric open-cell foams that are environmentally friendly and recyclable were developed for different applications including sound insulation using the injection molding machine process. This thesis work combines the conventional foam injection-molding process with mold opening and gas counter pressure techniques to achieve highly-expanded open-cell foam structures with/without an air-gap for sound insulation. Environmentally friendly and recyclable foams produced in this study showed promising results for sound insulation and sound absorption.

Keywords: Injection Molding
Insulation
Polymer
Sound
Advisor: Naguib, Hani H.N.
Diversity is (not) good enough: Unsettling White Settler Colonialism within Toronto's Queer Service Sector

This dissertation explores the ways in which queer service provision and non-Indigenous lesbian, gay, bisexual, queer, and trans (LGBTQ)-identified service providers in downtown Toronto can contribute to and become complicit in white settler colonial projects. During this study based on in-depth interviews, forty-three research participants were asked about their experiences working within their respective queer service organizations, and, more specifically, about their understandings of how diversity, anti-racism, and anti-colonialism are practiced. Findings highlight how queer service provision, particularly its perpetual crisis and capacity to care for queerness, can obscure the ways the organizations themselves contribute to the naturalization of a hierarchy of oppression that centralizes the needs of white queers. Additionally, I consider the narratives of white service providers' goodness as easily relocating Indigenous peoples as "problems" and "pathology" who then become unworthy of care. Moreover, this inquiry theorizes how the narratives offered by white service providers fit Indigenous peoples and people of colour into stories of Canadian multiculturalism. I show how non-Indigenous queer and trans service providers' evocations of diversity and inclusion easily deflect their implicatedness in white settler colonialism. Although queer service provision is a rich site of queer politics, it continues to be a site that is tied to state-sanctioned funding regimes and neoliberal models of care used to naturalize Indigenous peoples' elimination, erasure, and assimilation. Thus, this research contends that queer communities in downtown Toronto operate to sustain white supremacy and settler colonialism. I conclude with a set of questions that asks non-Indigenous service providers to engage with how they participate (often unknowingly) in white settler colonial projects, and move beyond queer service provision as a site of emancipation in order to meaningfully support Indigenous resurgence and decolonization.

Keywords: Qualitative
Queer
Settler Colonialism
Social Services
Toronto
White Racism
Advisor: Cannon, Martin