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    Rooted Elsewhere: Understanding the impact of immigration on health and wellbeing from the perspective of Black immigrant women in Ontario
    (University of Waterloo, 2025-11-28) Ike, Nnenna Arianzu Uma
    Introduction Canada has long relied on immigration to shape its demographic landscape, social fabric, and economic development. Historically, immigration policies have favoured white European settlers, but changes to the Canadian Immigration Act opened pathways for more diverse populations, including Black immigrants from the Caribbeans and various African countries. However, Black immigrants, particularly women, continue to face systemic inequities in healthcare, employment, housing, and other areas of life. Black immigrant women often carry the compounded weight of racialized and gendered expectations as they navigate caregiving responsibilities, financial pressures, and resettlement barriers in their new socio-cultural context in Canada. When combined, these social determinant of health can negatively impact their health and resilience as they resettle in Canada. Canadian immigrants are rigorously vetted for the positive educational, health and economic impact they can make to the economy however, their health start to decline after their arrival to the country. Though studies abound establishing patterns linking unmet needs, structural and institutional inequity to immigrant health, for Black immigrant women, health is further shaped by intersecting forces such as race, gender, and migration. While quantitative studies have captured broad patterns in immigrant health, they often fail to capture the lived experiences behind those numbers. This study offers critical insight into the social and emotional complexities of resettlement, health-seeking behaviours, and identity negotiation of immigrants and their impact on physical and mental health. It contributes to a growing body of qualitative scholarship that centres the voices of Black immigrant women in Canada, by offering a deeper understanding of how immigration and resettlement experiences shape their health and well-being. Research Aim This thesis explores the multifaceted immigration and resettlement experiences of Black immigrant women in Ontario, Canada, with a focus on the implications for their physical and mental health. To capture the depth and complexity of the participants’ experiences, this thesis is separated into three papers, each drawing from the same research question but having their own distinct aim. Paper one examines the resettlement challenges specifically encountered by Black immigrant women as they settle and integrate into the Canadian society. It highlights how meeting Canadian immigration eligibility criteria does not ensure effective integration into the Canadian society. It showcases specific resettlement challenges and the resultant impact on their health and wellbeing. Paper two captures the employment experiences of Black immigrant women in the Ontario labour market and produces a three-stage employment narrative common to all participants. Also, paper two highlights the physical and mental health impact associated with the three different stages, along with the different coping strategies deployed by the women. Paper three explores how Black immigrant women make sense of their immigration and resettlement experiences and how the meanings they ascribe to their experiences impact on their health and wellbeing. These meanings significantly influence their choices and behaviors and profoundly impacts their self-identity and engagement with the Canadian society. Methods This thesis employs a qualitative approach to immigrant health research. Purposive sampling recruited a total of twenty-two Black immigrant women living in Ontario, aged 18-54 years. The women participated in virtual and in-person semi-structured interviews that lasted between 45 minutes to two hours. Three analytical approaches were used. First, thematic analysis was utilized in paper one to systematically code and interpret the broader resettlement challenges encountered by participants, such as the persistent devaluation of foreign credentials, experiences of racialized housing discrimination and negative dietary acculturation. Paper two drew on Reissman and Polkinghorne’s narrative analysis approaches to construct a framework that mapped participants’ employment stories across three distinct phases: the initial entry to the labour market, the early employment period, and the longer-term navigation of workplace environment. Paper three used Interpretative Phenomenological Analysis (IPA) to delve into how participants made meaning of their immigration and resettlement experiences within their cultural and socio-political contexts. Findings Findings from the thematic analysis of paper one illuminate how structural and systemic barriers were internalized by the participants, and contribute to their heightened stress, feelings of marginalization, and prolonged sense of frustration which are closely tied to both physical and mental health outcomes. The themes in paper one are: 1.) Hopes and aspiration for a better life, 2.) Facing reality, and 3.) Intentionality. Also, paper one shows that the combination of resilience level and the ability to leverage social capital determine participants’ ability to effectively integrate into the Canadian society. Participants’ employment narratives in paper two expose the emotional strain and disrupted career trajectory experienced by the participants as they tried to continue their professional path after arriving in Canada. Paper two highlights how participants experience structural and social exclusion at the workplace and the resulting negative impact on their physical and mental health. Most importantly, paper two develops a three-stage narrative model of early employment of newcomer Black immigrant women in Ontario. This model links the devaluation of credential and professional experience and racialized gatekeeping of employment to health outcomes in Black immigrant women. Further, this narrative model highlights not only the challenges encountered during the different stages of the employment journey but also how these experiences can contribute to the onset and progression of imposter syndrome (IS). The Interpretive phenomenological Analysis (IPA) method used in paper three foregrounds the embodied and affective dimensions of resettlement by showing how the participants’ identities, aspirations, and understandings of their health evolved in response to both visible and invisible pressures from their immigration. Paper three shows how participants sense of immigration was different before and after their arrival in Canada. Further, it shows that how they internalised and made sense of their experiences determined the decisions and actions they take which in turn impacted on their health and wellbeing. By privileging participants sense-making, paper three reveals the Black immigrant woman’s nuanced portrait of resilience and negotiation of self identity in their destination country. Conclusion Paper one highlights the feelings of disadvantage and stress expressed by all the participants as a result of their resettlement experiences of dietary acculturation, housing and healthcare discrimination. It showcases the results of the intersectionality of the participants identities and how social capital influences the extent to which participants are were able to navigate their resettlement challenges. Paper two portrays how people internalise the devaluation of their educational and professional qualifications because of systemic barriers and sexism and racism in Canadian workplaces. Further, Paper two identifies how participants experience of the imposter syndrome has far-reaching effect on their physical and mental health. Also, it shows that somatic symptoms can be easily developed as a result of workplace stress, and if they are misdiagnosed or overlooked, can lead to more serious and chronic health conditions. Paper three shows that beyond physical relocation, immigration is a deeply emotional and psychological journey shaped by the intersecting forces of gender, race and identity. Participants’ experience of racial trauma and systemic exclusion resulted in a sense of resignation to conserve their emotional energy. However, they demonstrate resilience through positive reframing and biographical reinvention to reconstruct their self identity in order to live and thrive in Canada as an immigrant. Overall, the contributions of this thesis include: 1. A methodological contribution showing productive complementarity between Interpretative Phenomenological Analysis Narrative Inquiry, and Thematic Analysis for capturing both idiographic depth and substantive patterns across the dataset. 2. A theoretical refinement by demonstrating how the Intersectionality lens, backed by the Critical Race Theory, and Migration and Integration theories can be used to capture and categorize data for analytic navigation and story telling. 3. An empirical contribution by way of a three-stage narrative employment model for newcomer Black immigrant women in Ontario that links credential devaluation and racialized gatekeeping to health impacts. Ultimately, this thesis affirms that immigration and resettlement, for Black immigrant women, is not just about relocating and fitting in a new country but is about renegotiating their entire self-identity in environments with limited socio-cultural and professional support. When these are not appropriately addressed, will impact negatively on their health and wellbeing in their destination country.
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    Safety and Security of Reinforcement Learning for Autonomous Driving
    (University of Waterloo, 2025-11-27) Lohrasbi, Saeedeh
    In the context of autonomous driving, reinforcement learning (RL) presents a powerful paradigm: agents capable of learning to drive efficiently in unseen situations through experience. However, this promise is shadowed by a fundamental concern—how can we entrust decision-making to agents that rely on trial-and-error learning in safety-critical environments where errors may carry severe consequences? This thesis advances a step toward resolving this dilemma by integrating three foundational pillars: adversarial robustness, simulation realism, and model-based safety. We begin with a comprehensive survey of adversarial attacks and corresponding defences within the domains of deep learning (DL) and deep reinforcement learning (DRL) for autonomous vehicles. This survey reveals the porous boundary between safety and security—both natural disturbances and adversarial perturbations can destabilize learned policies. Motivated by this insight, we introduce the Optimism Induction Attack (OIA), a novel adversarial technique that manipulates an RL agent’s perception of safety, causing it to act with unwarranted confidence in hazardous situations. Evaluated in the context of an Adaptive Cruise Control (ACC) task, the OIA significantly impairs policy performance, exposing critical vulnerabilities in state-of-the-art RL algorithms. To counter the demonstrated threats, we present a systematic defence architecture. We develop REVEAL, a high-fidelity simulation framework designed to support the training and evaluation of safe RL agents under realistic vehicle dynamics, traffic scenarios, and adversarial conditions. By narrowing the gap between abstract simulation and real-world complexity, REVEAL facilitates rigorous and nuanced testing, which is essential for safety-critical applications. To enhance learning efficiency within this environment, we employ a transfer learning (TL) strategy: policies initially trained in simplified simulators (e.g., SUMO) are adapted and fine-tuned in REVEAL, leading to faster convergence and improved safety performance during both training and deployment. Central to our approach is the development of a Multi-Output Control Barrier Function (MO-CBF), which simultaneously supervises throttle and brake commands to enforce safety constraints in real time. Rather than relying on hard overrides, the MO-CBF operates cooperatively with the learning agent—gently adjusting unsafe actions and introducing corresponding penalties during training. This enables the agent not only to learn safe behaviour but also to internalize safety principles and anticipate potentially unsafe scenarios. Our empirical evaluation demonstrates the effectiveness of the proposed framework across a spectrum of disturbances, adversarial inputs, and realistic high-risk maneuvers. The results consistently show improved safety and robustness, highlighting the framework’s capacity to transform RL agents from vulnerable learners into trustworthy autonomous systems. In summary, this thesis presents a comprehensive methodology for safe and secure RL in autonomous driving. By grounding agent training in high-fidelity simulation, leveraging adversarial awareness, and embedding real-time model-based safety mechanisms, we provide a cohesive and scalable pathway toward deploying RL in the real world with confidence.
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    How Architectural Style, Height, and Complexity Influence Perceived Oppressiveness in Urban Spaces
    (University of Waterloo, 2025-11-27) Lapietra Garcia, Thomas
    The design of urban environments strongly influences psychological experience, yet research on how building form influences affective responses remains limited. This study used immersive virtual reality to examine the combined effects of architectural style (modern vs. contemporary), building height (low-, mid-, and high-rise), and façade complexity (low, medium, high) on affective perceptions of urban streetscapes. Forty-nine participants explored 18 virtual environments and rated each on oppressiveness, openness, restoration, arousal, and environmental liking. Results showed that greater building height consistently increased perceived oppressiveness and arousal while reducing openness, stress restoration, and liking. Greater façade complexity increased preference, openness, and restoration, and buffered the oppressive effects of high-rises, particularly in modern-style settings. Participants also expressed a clear preference for low- and mid-rise settings over high-rises. These findings reiterate and expand on the restorative and aesthetic benefits of architectural complexity and the value of human-scale design in supporting psychological well-being in urban dwellings.
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    Quantifying Endplate Deflection in Response to Cyclic Load Exposures Using a Porcine Cervical Spine Model
    (University of Waterloo, 2025-11-27) Watson, Michael
    The vertebral endplate is a thin layer of cartilage and bone that separates the intervertebral disc from adjacent vertebral bodies and facilitates the transmission of compressive force through the spine. Despite this essential function, it remains the weakest component of the vertebra-disc unit and is highly susceptible to mechanical failure. Endplate failure typically arises from localized tensile strains that manifest as deflection, defined as the out-of-plane displacement of the surface under load. While prior work has demonstrated inferior endplates of intervertebral joints exhibiting greater deflection and higher incidence of failure than their superior counterpart, current techniques for quantifying endplate deflection face notable limitations. Early studies using metallic markers or displacement transducers required drilling channels into the vertebral body, potentially exaggerating deformation by weakening subchondral bone support. Imaging-based approaches, particularly micro-CT, offer high spatial resolution but are limited to static or stepwise loading due to temporal constraints. These static conditions do not capture the cyclic loading patterns experienced by the spine during daily activity, where repeated deformation can cause fatigue-induced microdamage and eventual failure. Additionally, static loading promotes excess fluid loss from the nucleus pulposus, altering endplate deflections in ways that do not reflect physiological motion. Consequently, existing measurement techniques may misrepresent true endplate behavior and are unable to evaluate changes in deflection as a function of cyclic load exposure. This study addresses these limitations by developing a unique method to assess endplate deflection during cyclic loading without requiring prolonged stepwise protocols or causing damage to the vertebral bone. By comparing superior and inferior endplates across different load magnitudes and cyclic durations, this work aims to clarify the mechanisms underlying endplate vulnerability and further validate the porcine cervical spine as an experimental model for human lumbar spine deflection. Eighteen porcine cervical spine functional units (C3C4, C4C5, and C5C6; n = 6 per level) were dissected to yield 36 individual vertebrae. High-resolution laser profilometry was then used to capture the topography of the caudal endplates of C3, C4, and C5 and the cranial endplates of C4, C5, and C6. Custom indenters, designed as negative molds of the nucleus-occupying endplate region, were created from the resulting surface scans and fabricated via 3D printing. Specimens were then oriented such that the tested endplate was in a neutral position and subjected to a normalized haversine waveform, ranging from 0.3 kN to 30% of the predicted ultimate compressive strength using a servohydraulic materials testing system. The cycle-dependent changes in endplate deflection were measured at 0, 1000, 3000, and 5000 total cycles. At each time point, endplate deflection measurements were captured via the indenter’s displacement while specimens were exposed to a brief static force of 0.3 kN, 1 kN, and 3 kN, totaling 12 measurements per vertebra. Three separate linear mixed effects models were used to evaluate the impact of loading magnitude, loading cycles, endplate level and the proportion of the nucleus occupying endplate area on superior and inferior endplate deflection within each joint. A fourth linear mixed effects model was used to evaluate the impact of loading magnitude, loading cycles, and joint level on the magnitude of the differences between superior and inferior endplate deflection. Utilizing this novel methodology, this study was the first to quantify endplate deflection under cyclic loading conditions, observing greater deflection of the inferior endplate across all spinal levels, except at baseline (0.3 kN, 0 cycles). This method also enabled comparison of deflection rates between endplates, with the C4C5 and C5C6 inferior endplates showing a significantly greater rate of deflection during the first 1000 cycles. Among joints, C4C5 exhibited the largest difference in superior and inferior endplate deflection compared to C3C4 and C5C6. Endplate deflection was not influenced by the proportion of the nucleus occupying endplate area at any spinal level. Lastly, as the first study to examine endplate deflection in porcine cervical vertebrae, the observation of greater inferior endplate deflection being consistent with human cadaveric studies further supports the validity of this model. Overall, this study demonstrates the utility of a novel methodology for measuring and comparing superior and inferior endplate deflection under cyclic loading.
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    Zero-Knowledge Proof-Enabled SAT Co-processor for Blockchain Systems
    (University of Waterloo, 2025-11-26) Yusiuk, Vladyslav
    This thesis explores the possibility of building classical SAT solvers in Circom Domain Specific Language to create zero-knowledge proofs (ZKPs) usable in blockchain contexts. I implemented DPLL and Chaff as arithmetic circuits within Circom and analyze them based on constraint count, proving delay, and zk-SNARK verification layers. With this evaluation, the aim is to determine the feasibility of solvers integration into off-chain computation systems and rollup-centric architectures on Ethereum. The findings indicate that incorporating SAT solvers within zero-knowledge circuits is achievable though some degradation in efficiency occurs based on algorithm used and input representation. This research provides a thorough assessment of known SAT methods across an unconventional boundary, linking symbolic logic with blockchain technologies reliant on zk-SNARKs.