VictorJuiz/thesis huggingface dataset:
Improving Online Mirror Descent for Convex Optimization in Dynamic Environments
Keywords: Machine Learning
Online Convex Optimization

In many practical applications, system parameters and cost functions vary over time. For example, in online machine learning, data samples arrive dynamically, so that the learning model is progressively updated. It is difficult to capture such dynamics in an offline setting, while online optimization techniques naturally accommodate unpredictable variations in the system parameters. Online Convex Optimization (OCO) is a field in the intersection of optimization theory, machine learning, and control, which has recently attracted significant attention as an important tool for modeling various classes of problems in different application domains. One of the most popular algorithms in solving OCO problems is online mirror descent. Interesting theoretical and practical properties have made online mirror descent a powerful tool in solving large-scale and high-dimensional problems. However, the existing works on online mirror descent often make simplistic or impractical assumptions with respect to the cost functions and system model or propose inefficient solutions. In this dissertation, our aim is to propose efficient online algorithms based on mirror descent method with improved performance. We first consider the problem of distributed online convex optimization with a time-varying network topology. We propose the Distributed Online Mirror Descent with Multiple Averaging Decision and Gradient Consensus (DOMD-MADGC) algorithm in order to enable the local learners to accurately follow the sequence of global minimizers. We then consider a heterogeneous learning environment, where the processing speed can arbitrarily vary among the network nodes. We develop the Distributed Any-Batch Mirror Descent (DABMD) algorithm to speed up the progress of the network. Finally, we address the problem of centralized OCO without Lipschitz continuity. We show that it is still possible to guarantee the performance of online mirror descent algorithm even when Lipschitz continuity is not present. To further improve the performance, we propose the Online Multiple Mirror Descent (OMMD) algorithm that applied the mirror descent step multiple times to update the learner's decision. For each of these problems, we also use experimental results to compare against existing alternatives and study the performance of the proposed algorithms in various scenarios. We observe that the proposed online algorithms outperform other alternatives.
Motion and Driving: How Different Types of Physical Motion Cues Influence Driving Performance and Simulator Sickness in Younger and Older Adults
Keywords: 7-degree-of-freedom
Aging
Driving Simulator
Self-Motion Perception
Turntable
Virtual Reality

Vestibular function changes with older age, but the effects of these changes on functional activities requiring self-motion perception are largely unknown. Driving is a complex task that involves the use of vestibular inputs to guide self-motion perception and behaviours. However, little is known about how different types of physical motion (i.e., vestibular cues), such as yaw motion and full motion (7-degree-of-freedom) affect driving performance differently in younger and older adults. Driving simulators offer an effective means of studying the effects of physical motion cues on driving outcomes in younger and older adults. Chapter 2 of this thesis investigated how different kinds of motion cues (no motion, yaw motion, and full motion) affected simulated driving performance in younger and older adults. Driving environments were made up of eight scenario elements (e.g., curves, hills, turns) to strategically target vestibular cues. Results demonstrated that physical motion cues did not systematically and consistently affect driving performance across all scenario elements. The general patterns,iii however, suggest that added motion cues lead to better driving performance for both age groups, with effects being particularly apparent for certain driving metrics (e.g., mean speed). Driving simulators are also known to induce simulator sickness in some users. The prevalence and severity of simulator sickness is influenced by different factors, including motion capabilities and time of exposure. It is hypothesized that simulator sickness may be the result of sensory conflicts (visual-vestibular) and therefore, adding different types of congruent physical motion cues to visual displays may reduce symptoms. Therefore, in Chapter 3 using the same driving scenarios as Chapter 2, I investigated how different types of physical motion cues (no motion, yaw motion, and full motion) affect simulator sickness, over time of exposure, between younger and older adults. The results demonstrated no main effect of motion condition or age on simulator sickness, however, the addition of motion cues prevented simulator sickness from increasing over time of exposure. Together this thesis contributes to a fundamental understanding of how physical motions of different types influence self-motion perception, driving behaviours, and simulator sickness, which may have implications for vehicle and simulator-related research and application.
Police Use of Force: Understanding its Impact on Indigenous and Black Community Members in Ontario
Keywords: Canada
Indigenous and Black experiences
Ontario
police accountability
police use of force
policing

Police use of force is a critical area of concern, in Canada, North America, and globally. Issues around use of force have received considerable public attention in recent years due to several high-profile police-involved deaths of civilians, particularly racialized citizens. Using a mixed methods approach, this dissertation examines police use of force in Ontario and its impact on Indigenous and Black community members. An integrated framework of minority threat and social conflict theories, police working personality and symbolic interaction theories, and the concept of reputational risk is applied to help account for the findings. I argue that police use of force and its impact on certain communities is detrimental, multi-faceted, complex, and cannot be fully explained—in large part because of the lack of information made accessible on the subject. The qualitative section involves interviews with Indigenous and Black residents in Ontario to understand their perceptions of and experiences with police use of force. A primary finding is that many community members have been victims of police use of force—though, the types of force these members reported were overwhelmingly physical in nature (e.g., punching, kicking, knee-to-neck, roughhousing). Additionally, both Indigenous and Black individuals perceive that the police use force disproportionately against members from these groups compared to others. Moreover, the quantitative section provides an expansive analysis of police use of force over a 30-year period by examining use of force across all Ontario police services, lethal force incidents, and data from the Special Investigations Unit (SIU) to identify trends, patterns, and racial disparities in cases. Overall, the findings suggest that Indigenous and Black individuals in Ontario have been over-represented in use of force incidents consistently while other groups have been under-represented. The quantitative data also validate and support the perceptions and experiences shared by the Indigenous and Black community members. Despite the findings in this dissertation that highlight racial disparities in police use of force incidents, the limited information available on use of force by police services in Ontario underscores how much we do not know about this subject in the province. Future research and policy recommendations are provided.
Understanding Organist Occupational Injury: An Epidemiological Study of Canadian Organists
Keywords: Health
Injury
Musician
Organist
Prevention
Workplace

Musicians constantly face the hazard of playing-related overuse injuries. Organists are at particular risk of Playing Related Musculoskeletal Disorders (PRMDs) as they face many challenges not encountered by other instrumentalists, including extreme patterns of motion required by all four limbs, uncontrollable practice hours, as well as many other factors. Since the 1980s, researchers have recommended approaches to injury prevention, and many schools of instruments have performed instrument-specific surveys to gather data, leading to the development of prevention techniques within their teaching pedagogies. While the amount of pre-existing information for organ playing injury prevention is minimal, there is already some evidence suggesting that musculoskeletal injury risk factors exist for organists. Unfortunately, the pre-existing information is not substantial enough for the development of data-driven prevention recommendations specific to organists, leaving the school of organ pedagogy to continue to root itself in inherited playing techniques uninformed by modern research on musician, and specifically, organist injury prevention. This thesis seeks to contribute to the literature on organist injury and injury prevention with the purpose of furthering organ pedagogy’s understanding of organists PRMDs. Using Occupational Health as a focus of research, I have collected data which can be used to confirm that organists have musculoskeletal health problems as well as to act as building blocks towards future research and pedagogical developments in injury prevention for the profession. The primary tool used for this research was an anonymous epidemiological survey distributed to the membership of the Royal Canadian College of Organists. The content and results of the survey relate to: basic demographics; practice and performance habits; individual belief systems in relation to conceptual barriers to normalizing PRMDs; the contextual use of prevention and/or treatment resources; upper and lower body symptoms of pain and function (self-reported); awareness of, access to, and understanding of injury prevention information; experience with Occupational Health and Safety; and, experiences with the COVID-19 pandemic.
“I Think My Teacher Likes Me”: The Role of the Teacher- Student Relationship on the Mathematical Engagement and Achievement of Students with Socio-emotional Difficulties
Keywords: Engagement
Math Achievement
Math Anxiety
Socio-Emotional Difficulties
Teacher-Student Relationship Quality

The purpose of this dissertation was to explore the impact of teacher-student relationship quality (TSRQ) on students’ mathematical engagement and achievement, while considering how socioemotional difficulties play a role across these variables. The goals of this two-study dissertation were to (1) determine the profiles that exist among elementary school students’ mathematics anxiety, engagement, and achievement, and then to explore whether TSRQ predicts profile membership (Study 1) and (2) determine whether TSRQ differentially impacts the mathematical engagement of students with more socio-emotional difficulties (Study 2). The study took place at an inquiry-based school that embraces a philosophy of building secure relationships. Ninetyseven students across Grade 1 and 6 participated. In Study 1, latent profile analysis was used to identify types and number of profiles. Results revealed three profiles: one with moderate levels of anxiety and engagement (Class 1), one with highest levels of anxiety and lowest engagement (Class 2), and the last with lowest levels of anxiety and highest engagement (Class 3). Across all three profiles, mathematics achievement was in the average range. Students with highest TSRQ were more likely to belong to Class 3, those with moderate TSRQ to Class 1, and those with the lowest TSRQ to Class 2. Overall, this study revealed that the school’s evidence-based practices allowed for adequate achievement regardless of anxiety or engagement levels, and that students with stronger TSRQ have a more positive mathematics experience. In Study 2, moderation analysis was used to determine whether TSRQ has a differential association with mathematical engagement at the beginning and end of the school year for students with higher levels of externalizing difficulties, internalizing difficulties, and mathematics anxiety. Results revealed TSRQ predicts mathematics engagement at the beginning and end of the school year across all students, however, at the beginning of the year, this relationship is stronger for students with more internalizing challenges. There was no differential association for students with externalizing difficulties or for any socio-emotional difficulties by the end of the year. Results suggest that for students with certain emotional difficulties, TSRQ may protect against low mathematics engagement at the beginning of the school year.
The Hums: Feminist Listening and Gendered Affects in Music Production and Audio Engineering in Canada
Keywords: audio
ethnomusicology
feminism
gender
music industry
music technology

This dissertation articulates the entanglements of subtle and explicit pressures many women, trans, and gender non-conforming recordists face as they build professional careers in the recording arts in Canada. I present these affective pressure points of power as “hums”: a concept that elucidates the explicit and implicit accumulation of these feelings of un-belonging, which include experiences of isolation, marginalization, microagressions, violence, warnings, and whispers, and illuminates the way hums gradually aggregate in the body over time. I argue that hums and their abrasive “intimacy of body and world” (Ahmed 2017, 190) often go unnoticed by recordists and those involved in the broader music industries because they accumulate and operate on such a personal, subtle, and yet widespread level. I suggest that while it may be relatively rare for early-career women, trans, and gender non-conforming recordists to be outwardly discouraged from fully participating in the professional fields of music production and audio engineering, there are numerous ways to quietly dissuade systemically marginalized recordists from continuing on their chosen professional path. I attend to the particularities of these experiences of conditionality and exclusion based on extensive (auto)ethnographic fieldwork and in-depth interviews with recordists at various stages of their careers, examining three categories of hums cited as primary restrictions among my collaborators: a study of hums of neoliberalism, of violence, and of being included. Though presented as discrete, hums are always extended, overlapping and intersecting in their affects. However, this fluidity also allows for the potential for challenges and change. Therefore, as much as this work serves to illustrate the continuity and magnitude of ongoing issues, it also offers moments of transformation, of laughter, of hope, for the future of music production and audio engineering.
Neuroimaging and Reward Processing in Major Depressive Disorder and Mild Traumatic Brain Injury
Keywords: anhedonia
Major Depressive Disorder
mild traumatic brain injury
resting-state functional connectivity
reward processing
task-based fMRI

Major Depressive Disorder (MDD) is a common and disabling condition experienced by 20-45% of individuals who have suffered a mild traumatic brain injury (mTBI). The comorbidity of MDD and mTBI is associated with cumulatively worse outcomes, yet its neurobiological and behavioural presentation remains poorly understood. Importantly, while most literature has evaluated TBI groups with varying depressive symptom levels, scant research has investigated the impact of mTBI history among those with MDD. The current research sought to clarify this interaction with a focus on anhedonia and its underlying reward system, which are central to MDD and have preliminary evidence of disruption in mTBI. The substantial overlap in frontotemporal and limbic brain regions implicated in MDD, mTBI, and reward, combined with previous neuroimaging and reward findings in each condition separately, suggest a cumulative impact. Thus, the goals of the present studies were to understand the impact of mTBI history on resting-state functional connectivity (RSFC) and cortical thickness among those with MDD, and assess the combined impact of MDD and mTBI on anhedonia and reward function. Four participant groups were recruited across two studies: (1) MDD-alone, (2) mTBI-alone, (3) MDD+mTBI, and (4) healthy control participants. Together, clinical and neuroimaging findings converged to suggest that MDD is the main contributor to the interaction between MDD and mTBI, with significant differences observed between those with and without MDD, but limited separation by mTBI history. Subtle differences between MDD-alone and MDD+mTBI groups emerged, with altered sgACC-precuneus connectivity and more intact reward learning among MDD+mTBI participants, as well as trends toward altered cortical thickness in temporal regions. However, mTBI history within MDD was not associated with large-scale network differences in this cohort. In the present sample, we also found no evidence of differences in reward valuation, motivation, or response bias based on MDD or mTBI history. This work is the first to report the impact of mTBI history on RSFC and cortical thickness among those with MDD, as well as reward outcomes in MDD+mTBI versus either alone. Findings strongly support inclusion of MDD-alone groups in future studies of TBI and depression given its substantial impact on this interaction.
Online Research and Comprehension Process and Experience for Postsecondary Students with Learning and Attention Disorders
Keywords: Attention Deficit Hyperactivity Disorder
Inclusive Pedagogy
Lived Experience
Online Learning
Online research and comprehension
Specific Learning Disorder

Students with disabilities are increasingly participating in higher education compared to previous years and continue to face barriers to achievement, wellbeing, and sense of inclusion. Understanding how these students experience and engage in universal academic activities, such as online research and information comprehension, will allow educators to better support them. This dissertation includes two qualitative studies exploring the process and experience of online research and comprehension for postsecondary students with learning and attention disorders, respectively. Fifteen students with a specific learning disorder and/or attention- deficit/hyperactivity disorder completed questionnaires, a recorded online research and comprehension task, a virtual-revisit think aloud protocol, and a semi-structured interview. Data were analysed using constructivist grounded theory methodology in Study 1 to generate a theoretical model of the process of the phenomenon. In addition to engaging in navigational, comprehension, and output activities, students also described a process of managing feelings of overwhelm. Both sources of overwhelm (i.e., disorientation, pop-ups, performance) and overwhelm-management strategies (i.e., emotion regulation, boosting focus, problem solving, capturing information for future use, stepped-up evaluation) are described as well as the impact of time and experience on the process. To contextualize and enrich the theoretical model of the process generated in Study 1, Study 2 used the same data for a phenomenological analysis to describe and interpret the experience of online research and comprehension for students with learning and attention disorders. Themes related to students’ awareness of their disability, distraction, urge to control/contain/compartmentalize, self-efficacy, and experience of support emerged from the data and are described.Overall, the findings from this dissertation illuminate barriers to, and facilitators of, online research and comprehension for postsecondary students with learning and attention disorders. Pedagogical implications are described. In addition, key variables of the phenomenon are highlighted from an emic perspective to guide future inquiry in a meaningful direction for those with lived experience.
Roles and the Filtering of Reasons
Keywords: Discretion
Institutions
Integrity
Normative Reasons
Professional Ethics
Roles

This is a moral theory of roles. It asks how the special rules and purposes of institutions (such as legal systems, corporations, and governments) can change the moral rights and responsibilities of role occupants (such as lawyers, managers, and politicians). Its answer, the filtering account, is that legitimate institutions selectively filter the considerations that a role occupant may or must give weight to in doing her job. On this view, to perform a role with integrity is to respect the scope of the role’s filters, sifting the reasons for action that must be excluded from those that must remain on the moral scales. The filtering account is distinguished from two alternatives in the literature: the view that roles simply add additional reasons to the balance, and the view that roles entirely shield their occupants from ordinary moral criticism. The account is further explained in terms of a distinction between first-order and second-order reasons, which is then applied to a colourful range of examples—featuring cynical corporate lobbyists and conflicted criminal lawyers, unflinching public regulators and buck-passing middle managers. The result is a system for understanding the moral structure of roles, including the bounds of professional discretion, the ethics of official disobedience, and the relationship between individual and institutional integrity. The view is presented as a liberal theory in its respect for the moral claims of legitimate roles, as a critical theory in its diagnosis of the tendency for those same claims to be stretched and distorted.