Theses

Permanent URI for this collectionhttps://uwspace.uwaterloo.ca/handle/10012/6

The theses in UWSpace are publicly accessible unless restricted due to publication or patent pending.

This collection includes a subset of theses submitted by graduates of the University of Waterloo as a partial requirement of a degree program at the Master's or PhD level. It includes all electronically submitted theses. (Electronic submission was optional from 1996 through 2006. Electronic submission became the default submission format in October 2006.)

This collection also includes a subset of UW theses that were scanned through the Theses Canada program. (The subset includes UW PhD theses from 1998 - 2002.)

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Lake Ice Thickness Retrieval from SWOT and Legacy Spaceborne SAR Altimetry
(University of Waterloo, 2026-01-08) Fatt, Jennifer
Lakes play a critical role as climate change proxies and cover a significant portion of the northern latitude landscape. Lake ice phenology offers valuable insight into changing climate patterns, yet in-situ observations of lake ice have declined substantially in recent decades. This observational gap underscores the growing importance of remote sensing as a tool for understanding and monitoring lake ice. Northern and remote communities particularly rely on lake ice quality, quantity, and thickness for transportation on ice roads, subsistence activities, and recreational use. There has been limited research exploring the use of satellite altimetry for the retrieval of lake ice thickness (LIT); however, its efficacy and utility have been highlighted in recent studies. The Ku-band SWOT (Surface Water and Ocean Topography) nadir altimeter (NAlt) provides an opportunity to retrieve ice properties and directly measure ice thickness. This study assesses the retrieval of LIT from SAR altimeters aboard the legacy Sentinel-3 and Sentinel-6 sensors over the winter seasons 2019 to 2025 on Lhù’ààn Mân (Kluane Lake), Yukon, and compares it with the estimated LIT derived from the SWOT altimeter analysis. LIT can be determined using Ku-band altimetry through the analysis of double-peaked waveforms characteristic of lake ice formed by the interaction of the radar signal with the ice interfaces. The utilization of SWOT altimetry has the potential to advance understanding of lake ice processes and to provide valuable datasets for d hydrological models, as well as overall resource management. This thesis discusses the potential applications of SWOT altimetry in lake ice thickness retrieval, emphasizing its capacity to fill critical data gaps. This study implements a dual-peak waveform methodology to estimate LIT using SWOT NAlt and reports an overall RMSE of <0.15m for the SWOT scientific period 2024-2025.
Development of a 7-item Dietary Screener Questionnaire for Determining Intakes of Eicosapentaenoic and Docosahexaenoic Acid in Canadians
(University of Waterloo, 2026-01-08) Liu, Ming Rong
The intakes of the omega-3 polyunsaturated acids, eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) are associated with various health benefits. The main dietary sources of EPA and DHA are seafood, but there are non-seafood sources that contain significant amounts of EPA and DHA. Determining the dietary intake of EPA and DHA can be challenging due to the sporadic nature of seafood intake. An online 7-item dietary screener has been used to estimate the DHA intake of pregnant women from both seafood and non-seafood sources in the United States. Using this screener as a template, a Canadian screener for estimating EPA and DHA intakes was developed. In Project 1, EPA values were added and DHA values revised to match those in the Canadian Nutrient File, the questions were reordered to focus on seafood commonly consumed, questions about eggs were expanded to include options for size and omega-3 enrichment, and a French version of the screener was developed. In Project 2, fatty acid quantitation analyses were completed on screener items when the Canadian Nutrient File EPA and DHA data was either missing or not consistent with literature. This included eggs (medium, large, extra-large, omega-3, and omega-3 plus), liver (beef, pork, and chicken), and chicken (regular and organic). For Project 3, the “Canadianized” screener was evaluated for errors using mock. To do this, intake information from the 24-hour dietary recalls in the 2015 Canadian Community Health Survey (CCHS) were extrapolated to bimonthly intakes and entered into the screener. The EPA and DHA intakes estimates from the screener agreed with those from the CCHS 2015 Nutrition, indicating that the Canadian screener is ready for a proper validation study in the future. Once validated, this online tool should be able to improve our ability to estimate the intakes of EPA and DHA by Canadians. In addition, the process that was used to “Canadianize” the screener can be used as a template top adapt the screener for different countries.
Label-free optical microscopy: Photon Absorption Remote Sensing (PARS) and other methods for label-free histopathological imaging of tissues
(University of Waterloo, 2026-01-08) Ecclestone, Benjamin
Emerging label-free microscopy methods offer promising new avenues to view cells and tissues in their native environment, minimizing external influences. These label-free techniques are an exciting departure from gold standard methods for visualizing microscopic cellular and tissue structures, which rely on centuries-old chemical staining processes. In current practice, chemical labelling can unavoidably interfere with specimens’ physical and biochemical integrity. As a result, samples are effectively consumed by staining with only a single stain set normally applied to each sample. This limitation is especially impactful in applications such as clinical oncology and medical histopathology. In these settings, irreversible staining processes can severely limit the diagnostic utility of samples; especially when there is limited sample volume (e.g., brain tumor biopsies). As an alternative, label-free imaging techniques offer a potential avenue to visualize subcellular tissue anatomy while preserving samples in their entirety. Subsequently label-free microscopy methods have significant potential to greatly increase the diagnostic utility of each specimen, thereby enhancing patient outcomes. This thesis focuses on developing new methods for label-free microscopy, specifically emphasizing techniques for label-free histopathology. As a starting point the targeted objective is to develop a label-free analog to chemical hematoxylin and eosin (H&E) staining. This objective is chosen as H&E represents the gold standard contrast applied in effectively every clinical diagnostic case. Subsequent developments in this thesis can be broken into three major sections, which focus on (1) developing label-free microscopy methods for H&E-like imaging, (2) exploring the biomolecular specificity of developed methods to validate the label-free H&E-like contrast, and (3) producing a label-free microscopy architecture capable of meeting the imaging requirements necessary for clinical adoption. The first collection of works explores the development of a range of label-free microscopy methods. These studies establish new variations and combinations of optical absorption and scattering microscopes to visualize microscopic tissue anatomy label-free. These efforts ultimately resulted in the development of a new optical absorption microscopy modality, Photon Absorption Remote Sensing (PARS). This comprehensive technique provides biomolecule-specific visualizations characterizing the dominant photophysical effects caused when photons are absorbed by a biomolecule. As a direct result, novel PARS specific contrasts are developed as the total absorption (TA) and quantum efficiency ratio (QER). These PARS measurements may provide unique views into biomolecules’ excited state dynamics, accessing characteristics related to the quantum yield. By specifically probing specimens’ response to the absorption of deep ultraviolet light, PARS is shown to provide label-free contrast directly reminiscent of gold standard chemical H&E staining methods. As a proof of concept, the initial PARS architecture is applied to capture submicron resolution images of key H&E-like diagnostic markers across a variety of human and animal tissue specimens. The second section of this thesis expands the basis for PARS histopathology by validating PARS capacity to produce H&E-like visualizations. Two main avenues of exploration are pursued in this effort. The first endeavor explores the underlying biomolecular contrast of the PARS measurements. Established statistical methods are applied to develop characteristic PARS profiles for biomolecules. These PARS signatures are then applied to map the abundance of molecules label-free inside complex specimens. As a proof of concept, key diagnostic features including nuclei, red blood cells, and connective tissues are directly characterized and unmixed label-free. Resulting statistical abundance mappings are directly validated against chemically stained ground truth counterparts. The second endeavor introduces an end-to-end pipeline which uses deep learning-based image-to-image transforms to emulate chemical H&E visualizations from label-free PARS data. Resulting PARS emulated H&E-like visualizations are validated against chemical H&E staining through a clinical concordance study. In this diagnostic validation study, statistical analysis is applied to determine if pathologists produce the same diagnoses on both PARS and chemical H&E images. In this preliminary test, the PARS-based virtual staining method achieves > 90% concordance with very high statistical confidence (Kappa > 0.7) across all measured diagnostic tests. The final thesis section develops a new PARS architecture which achieves pragmatic imaging performance, nearing the requirements for clinical diagnostic settings. The presented system features a hybrid opto-mechanical scanning architecture which allows for high-speed MHz rate imaging. This results in imaging speeds which are more than an order of magnitude faster than earlier PARS embodiments developed in the PhotoMedicine Labs (at the University of Waterloo). This work simultaneously develops an end-to-end control system and imaging workflow which enables fully automated PARS imaging of whole specimens. Deep learning methods are applied to the resulting PARS images to produce virtual H&E-like visualizations. Qualitative and quantitative methods are applied to validate the imaging performance across a range of human and animal tissue samples. Results indicate the PARS virtual H&E images are largely indistinguishable from chemically H&E-stained ground truth images. Notably, the presented system forms the basis for a commercially available clinically ready prototype for label-free PARS histopathology imaging. In total, the findings presented across this thesis encompass the development of a new variation of microscopy technique (PARS). This method provides unique views into the absorption and scattering characteristics of specimens opening a new avenue of label-free contrast. For the presented histopathology application, PARS can provide powerful H&E-like images which may circumvent key challenges of chemical staining. In clinical histopathology, this method could enhance the diagnostic utility of tissue specimens directly improving patient outcomes. Beyond histopathology, the principles of PARS may be directly applicable to a wide range of imaging applications spanning material science, biological research, and clinical diagnostics. Overall, the methods developed in this thesis lays the groundwork for new label-free optical absorption microscopy techniques, which are already achieving real-world commercial and clinical success in histopathology applications.
Advancing Semi-Supervised Domain Adaptive Semantic Segmentation Through Effective Source Integration Strategies
(University of Waterloo, 2026-01-08) Kurien, Joshua
Semantic segmentation is a highly valuable visual recognition task with applications across fields such as medical imaging, remote sensing, and manufacturing. However, training segmentation models is challenging because it requires large-scale, densely labeled data specific to the target. Semi-supervised learning (SSL) addresses this challenge by leveraging unlabeled data alongside limited labeled data, reducing the reliance on fully labeled datasets. Semi-supervised domain adaptation (SSDA) further mitigates this issue by incorporating labeled data from a source domain alongside minimally labeled target data. While existing SSDA methods often underperform compared to fully supervised approaches, recent SSL methods that utilize foundation models achieve near fully supervised performance. Given the strength of current SSL methods using foundation models, this thesis investigates effective strategies for integrating source-domain data from a different distribution into existing pipelines to improve segmentation performance. First, we explore a simple source transfer mechanism that merges target and source data into a single unified labeled set for SSL pipelines. Our analysis demonstrates the accuracy benefits of this setup while also highlighting some downsides, particularly in terms of training efficiency. We also examine the use of ensembling SSL and SSDA models to enhance target-domain performance. This ensemble combines a model trained solely on target data with a source-transferred SSDA model. We find that ensembling can improve performance in certain cases but is less effective in others, and training efficiency remains suboptimal due to the need to train two models. Given the training inefficiencies of simple source transfer and ensembling, we propose a dual-curriculum source integration strategy to address and improve these limitations. This approach consists of two complementary learning strategies: curriculum retrieval, which progressively samples source examples from easy to hard, and curriculum pasting, which increases the diversity of target-labeled data. Across our experiments, we compare against and outperform state-of-the-art SSL and SSDA methods on a variety of benchmarks, including synthetic-to-real and real-to-real scenarios. Our findings highlight the benefits of effective source data integration into modern SSL pipelines for boosting segmentation performance, opening a new avenue for label-efficient semantic segmentation.
REMind: A Robot Role-Playing Game To Promote Bystander Intervention
(University of Waterloo, 2026-01-07) Sanoubari, Elaheh
Peer bullying is a pervasive social problem, with bystanders' inaction being a critical challenge despite widespread disapproval of bullying. Effective intervention strategies must move beyond explanation-based instruction to facilitate embodied situated learning. This dissertation explores how social robots can serve as mediators for applied drama to foster prosocial bystander intervention in the context of peer bullying. It introduces Robot-Mediated Applied Drama (RMAD): an innovative framework that integrates drama-based pedagogy with social robotics to create safe, reflective, and embodied learning experiences. Using a Research through Design (RtD) methodology, this work advances through an iterative sequence of design studies that culminate in the development and evaluation of REMind (short for Robots Empowering Minds): a mixed-reality role-playing game where children engage in dramatized bullying scenarios performed by social robots. In REMind, three robots enact a conflict involving a bully, a victim, and a passive bystander. Players are invited to assume control of robotic avatar, reflect on the unfolding narrative, and improvise an intervention by using the robot as a proxy in order to change the story’s outcome. Through this structure, children rehearse bystander intervention strategies within a psychologically safe, yet emotionally engaging environment. The iterative design process of REMind unfolded across complementary empirical inquiries. A crowdsourced feasibility study first established that observers perceive aggression toward robots as morally wrong, validating the viability of using robots in the intervention. A narrative co-design study with children revealed storytelling patterns such as preferences for emotionally expressive and customizable robot characters. Interviews with teachers grounded the design in classroom realities, identifying gaps in existing programs. A game design focus group study further examined what makes educational robot role-play games pleasurable for children, leading to identifying concrete design elements that informed REMind’s interactive components such as core mechanics, use of tangible props, world aesthetics and narrative structure. This dissertation presents the resulting artifact, REMind, as a system consisting of five interconnected components: Learning Goals, Mechanics, Narrative, Technology, and Aesthetics. The learning goals were defined through consultation with subject-matter experts to ensure grounding in evidence-based best practices. By deliberate aligning the game pleasures identified in prior studies with the learning objectives, REMind introduces a suite of game mechanics that scaffold socio-emotional skills (such as robot-mediated spect-actorship or "puppet mode" for moral intervention, interpretation of immersive affective displays for empathy-training and perspective taking, and custom-made logic-gate puzzles for moral reasoning). Narrative design is scaffolded by borrowing a five-step cognitive model of bystander intervention from social psychology. The technical implementation is realized through StorySync, a novel spreadsheet-based scripting toolkit developed to synchronize multimodal cues (including multiple robots, graphical interfaces, ambient lighting, and sound) and manage narrative branching for live interactive robot drama. Finally, the aesthetic elements leverages emotional design, ambient cues, and digital scenography to create an emotionally resonant learning experience. This concrete high-fidelity prototype serves as a proof of concept for RMAD. This research contributes a theoretical and practical foundation for designing robot-mediated experiential learning systems, offering RMAD as a new direction for social robotics and educational technology. It further illustrates how embodied storytelling and interactive systems design might cultivate reflective, prosocial action in a complex domain of social-emotional learning. More broadly, it advocates for a shift in Human-Robot Interaction (HRI) research toward systems thinking, positioning game design as a powerful systems lens for creating and analyzing holistic user experiences.
Two-sample Inference, Order Determination, and Data Integration for Functional Data
(University of Waterloo, 2026-01-07) Zhang, Chi
Functional data analysis has gained increasing prominence in modern statistics, largely due to advancements in data collection technologies. It provides a nonparametric framework for analyzing discrete observations obtained from realizations of a continuous random function, often defined over time or space. In this thesis, we focus on three distinct problems, each reflecting a different aspect of functional data analysis. In Chapter 2, we address the problem of comparing mean functions between two groups of sparse functional data within the framework of a reproducing kernel Hilbert space. The proposed method is well-suited for sparsely and irregularly sampled functional data. Traditional approaches often assume homogeneous covariance structures across groups, an assumption that is difficult to justify in practice. To circumvent this limitation, we first develop a novel linear approximation for the mean estimator, which naturally leads to its desirable pointwise limiting distributions. Furthermore, we establish the weak convergence of the mean estimator, enabling the construction of a test statistic for the mean differences. The finite-sample performance of our method is demonstrated through extensive simulations and two real-world applications. In Chapter 3, we study the problem of determining the number of eigenpairs to retain in functional principal component analysis---a problem commonly referred to as order determination. When a covariance function admits a finite representation, the challenge becomes estimating the rank of the corresponding covariance operator. While this problem is straightforward when the full trajectories of functional data are available, in practice, functional data are typically collected discretely and are subject to measurement error contamination. Such contamination introduces a ridge in the empirical covariance function, obscuring the true rank. We develop a novel procedure to identify the true rank of the covariance operator by leveraging the information of eigenvalues and eigenfunctions. By incorporating smoothing techniques to accommodate the nonparametric nature of functional data, the method is applicable to functional data collected at random, subject-specific points. Extensive simulation studies demonstrate the excellent performance of our approach across a wide range of settings, outperforming commonly used information-criterion-based methods and maintaining effectiveness even in high-noise scenarios. We further illustrate our method with two real-world data examples. In Chapter 4, we investigate the integration of multi-source functional data to extract a subspace that captures the variation shared across sources. In practice, data collection procedures often follow source-specific protocols. Directly averaging sample covariance operators across sources implicitly assumes homogeneity, which may lead to biased recovery of both shared and source-specific variation structures. To address this issue, we propose a projection-based data integration method that explicitly separates the shared and source-specific subspaces. The method first estimates source-specific projection operators via smoothing to accommodate the nonparametric nature of functional data. The shared subspace is then isolated by examining the eigenvalues of the averaged projection operator across all sources. If a source-specific subspace is of interest, we re-project the associated source-specific covariance estimator onto the subspace orthogonal to the estimated shared subspace, and estimate the source-specific subspace from the resulting projection. We further establish the asymptotic properties of both the shared and source-specific subspace estimators. Extensive simulation studies demonstrate the effectiveness of the proposed method across a wide range of settings. Finally, we illustrate its practical utility with an example of air pollutants data.
Pretending Architecture: The Journey Towards Verne Station
(University of Waterloo, 2026-01-07) Ferreira, Jamie Verdell
This is a record of pretend architecture, a journey of fabricating fantasy in the form of a virtual environment that is an authentic fake. This is an exploration inspired by the many fictional stories that I have encountered in order to create an interpretation of a space station. Framed by the harsh reality of space and contrasted by idealistic viewpoints in film, literature and video games, the end result presented is a far cry from initial expectations. It is a means to an end; a way to explore architecture in outer space with the use of constructs. Verne Station exists as fragments of experiences; attempts to understand and discover the intoxicating ideals of a limitless frontier ruled by the harshest of living conditions. By use of the machine, one has the ability to create complex virtual environments to simulate and visualize space architecture concepts; a field that has historically been inaccessible to many. By simulating different scales of artificial gravity design, the real-time exploration of designed spaces can facilitate a clearer understanding and more effective visual feedback of potential space architecture designs. This is a thesis about coming to terms with not arriving at your original destination, the one you imagine and expect to reach, but instead, the real one which you never quite anticipated.
The Effects of Reward Nature and Reward Contingency on Employee Voluntary Training
(University of Waterloo, 2026-01-07) Wang, Pei
Despite firms investing billions of dollars in voluntary training, employees’ skills still fall behind what firms need. Therefore, managers must motivate employees to allocate more effort toward voluntary training. In a multi-task setting where effort allocated to both production and voluntary training can increase employee performance, I examine how two attributes of performance-based rewards – reward nature (hedonic vs. utilitarian) and reward contingency (goal-based vs. piece-rate) – affect employee total effort, voluntary training effort proportion, and performance. Using a lab experiment, I find that the effect of hedonic (vs. utilitarian) reward nature on employee total effort is more positive when the reward is goal-based than piece-rate; the effect of hedonic (vs. utilitarian) reward nature on employee voluntary training effort proportion is more negative when the reward is goal-based than piece-rate; and the effect of hedonic (vs. utilitarian) reward nature on employee performance is more positive when the reward is goal-based than piece-rate. These results inform managers of the need to consider reward nature and reward contingency together in reward design: adjusting the reward nature is likely more useful in balancing employees’ production effort and voluntary training effort for jobs where goal-based rewards are offered than for jobs where piece-rate rewards are offered. Utilitarian reward nature can motivate employees to allocate more time to training than hedonic reward nature when the reward is goal-based; however, reward nature matters less when the reward is piece-rate.
Demystifying Foreground-Background Memorization in Diffusion Models
(University of Waterloo, 2026-01-07) Di, Jimmy Z.
Diffusion models (DMs) memorize training images and can reproduce near-duplicates during generation. Current detection methods identify verbatim memorization but fail to capture two critical aspects: quantifying partial memorization occurring in small image regions, and memorization patterns beyond specific prompt-image pairs. To address these limitations, we propose Foreground Background Memorization (FB-Mem), a novel segmentation-based metric that classifies and quantifies memorized regions within generated images. Our method reveals that memorization is more pervasive than previously understood: (1) individual generations from single prompts may be linked to clusters of similar training images, revealing complex memorization patterns that extend beyond one-to-one correspondences; and (2) existing model-level mitigation methods, such as neuron deactivation and pruning, fail to eliminate local memorization, which persists particularly in foreground regions. Our work establishes an effective framework for measuring memorization in diffusion models, demonstrates the inadequacy of current mitigation approaches, and proposes a stronger mitigation method using a clustering approach.
Micro-Calorimeter X-Ray Spectroscopy of Galaxy Clusters using the XRISM X-Ray Observatory
(University of Waterloo, 2026-01-07) Meunier, Julian
Galaxy clusters are some of the most massive objects in the universe, yet the evolution of these objects, particularly with regards to the heating and cooling of the intracluster medium, still has many unknowns. With the launch of the new X-ray imaging and spectroscopy mission, XRISM, galaxy clusters can now be studied with higher precision. This data can reveal a plethora of new information about the dynamics of the atmospheres of these clusters, which can be used to develop a better understanding of the evolution of galaxy clusters. In this thesis, I present analysis of X-ray spectroscopic data of the Perseus, Hydra A, and Cygnus A clusters obtained with XRISM Resolve. We apply spectral modeling techniques to the data to derive gas temperature, metal abundance, velocity dispersion, and bulk velocity to develop a further understanding of the dynamics of the intracluster medium in these galaxy clusters. I present spectral analysis of the five XRISM Resolve pointings of the Perseus cluster, binned into a radial profile. We measure radial profiles of temperature, metal abundances, velocity dispersion, and bulk velocities up to $\sim250$ kpc from the cluster center with single temperature models. While the temperature and abundance profiles are consistent with typical cool core clusters, the velocity dispersions suggest a relatively quiescent state for the intracluster medium, with only up to $\sim175$ km s$^{-1}$ dispersion in the central $\sim 60$ kpc. We interpret this velocity dispersion to be due to turbulence. The dispersion profile suggests that the jets and bubbles may be driving turbulence in the core, but also that the core may be under-heated. We find evidence for a second temperature component in the inner $\sim60$ kpc, that is cooler ($\sim2-2.4$ keV) and has a significantly higher velocity dispersion of $\sim300-400$ km s$^{-1}$. We interpret the cooler component to be sloshing gas from a merger or gas being churned by the jets and bubbles. I present spectral analysis of the full-FOV XRISM Resolve data of the Hydra A cluster, measuring temperature, velocity dispersion, and bulk velocity with a single temperature model. Despite Hydra A's high jet power, we find a remarkably low velocity dispersion of $164^{+10}_{-10}$ km s$^{-1}$, and a small velocity offset of $-37^{+20}_{-17}$ km s$^{-1}$ between the gas and the central galaxy. We interpret this velocity dispersion to be due to turbulence, which may suggest that the relationship between the jet power and the velocity structure of the intracluster medium is less significant than expected. However, further analysis of the outer regions of the cluster is needed to fully understand the dynamics of the gas in Hydra A. Finally, I present spectral analysis of the full-FOV XRISM Resolve data of the Cygnus A cluster, measuring temperature, metal abundances, velocity dispersion, and bulk velocity with a single temperature model. We measure a relatively higher velocity dispersion of $272^{+14}_{-13}$ km s$^{-1}$ with a bulk velocity of $101\pm26$ km s$^{-1}$ with respect to the central galaxy. These velocities likely reflect a combination of both turbulence in the gas and motion of the cocoon shock. We find some evidence for a second temperature component, that is cooler ($2.06^{+0.43}_{-0.20}$ keV) and broader ($333^{+127}_{-129}$ km s$^{-1}$), with a bulk velocity of $-311\pm118$ km s$^{-1}$. The second component may be necessary for fitting asymmetric features in the prominent emission lines of the spectrum. However, the large uncertainties of the model fit along with other uncertainties suggest that this component may not be significant.
Development and Evaluation of Hydrophobic Catalysts for Deuterium Enrichment in a Gas-Vapor Reactor
(University of Waterloo, 2026-01-07) Lau, Jordan
Deuterium, an isotope of hydrogen, has found diverse applications in pharmaceutical, nuclear, and analytical fields owing to its chemical similarity to protium, but distinct mass which gives rise to the kinetic isotope effect. The water-hydrogen catalysis method offers a clean route for deuterium enrichment from its natural abundance (0.015 %). This process can achieve industrial-grade purity (> 99 %) in the presence of a hydrophobic catalyst. However, the industrially used Pt/C/PTFE catalyst is costly, making the initial capital requirement for deuterium enrichment high. Further, limited documentation on the synthesis and performance of Pt/C/PTFE hinders the development of viable alternatives. This thesis develops a co-current gas-phase reactor and tests its ability to directly study kinetics for catalysts that perform deuterium enrichment through isotopic exchange between H2/H2O. A protocol for a Pt/C/PTFE catalyst was developed and standardized. This catalyst was used to establish benchmark catalytic performance metrics for deuterium enrichment of H2O by catalytic exchange between a blended H2/D2 and H2O vapor stream. A series of Ni-Pt alloys were then explored as low-Pt alternatives to this industry standard catalyst. The reaction temperature and reaction time required for alloying of NiPt with stoichiometric ratios of 1Ni:3Pt, 1Ni:1Pt and 3Ni:1Pt were established. The resultant alloy nanoparticles were prepared into Ni-Pt/C/PTFE catalysts, analogous to the industry standard Pt catalyst, and their catalytic properties were tested. A reliable evaluation method for assessing catalytic activity was developed, through which mass-transfer coefficients and activation energies were determined. Comparative analysis showed the NiPt/C/PTFE alloy to successfully catalyze the isotopic exchange reactions but not outperform Pt/C/PTFE. Mechanistic analysis provides evidence for OH* oversaturating the surface at elevated temperatures in the reaction, which may be responsible for lower-than-anticipated catalytic performance. Further investigations into temperature-dependent kinetics may guide the rational design of cost-effective catalyst for deuterium enrichment.
Unfettering the Voices of Palestinian Women: Counterstorytelling Against Dehumanization, Suppression, and Genocide
(University of Waterloo, 2026-01-07) Gallant-Turner, Jordan
My thesis uses the opportunity and its platform to amplify the voices of Palestinian women while Palestine is enduring a holocaust by the settler-colonial regime known as ‘israel.’ I have chosen to read the life writing of four Palestinian women to provide a historical survey that contextualizes Palestine—whose people and voice has long been dehumanized and suppressed within western cultural and political spaces. These women, who include Fadwa Tuqan, Leila Khaled, Bisan Owda and Jenan Matari, participate in an overall objective towards counterstorytelling for the purpose of social justice for Palestine, Palestinians, and Palestinian women. I believe it is necessary to understand the circumstances and context of the Palestinian reality in order to recognize the depth of the propagandic nature of the dominant western narrative and locates the necessity of counterstorytelling which dismantles hegemonic narratives, highlights double standards, and strives for the liberation of Palestine. In the Introduction I include: my positionality while introducing background information to help situate the reader in discourse of Palestinian feminist liberation, the culture of resistance which has developed historically in Palestine, an introduction of my voices and offer a brief history of Palestinian women’s activism and popular resistance. In Chapter One I analyze and compare two Palestinian women’s autobiographies, Tuqan’s A Mountainous Journey: An Autobiography and Khaled’s My People Shall Live: Autobiography of a revolutionary by Leila Khaled as told to George Hajjar which are read through a Critical Race Theory (CRT) and feminist lens. Tuqan’s autobiography provides an emotional and poetic description of conservative patriarchy as her foremost oppressor as she lived through the imperial British Mandate, the growing zionist threat/invasion, the Nakba and Naksa. Khaled’s autobiography is written much closer to counterstorytelling as she presents the suppressed history and brutality of imperialism and zionism against Palestinians. She completes her counterstory by using her personal narrative as a central structure from which to tell the collective story of Palestine. In Chapter Two I first illustrate how Palestine/Palestinians are being silenced through habitual media and social media censorship. After illustrating the pro-‘israel’ bias of western media/institutions/politics I present the voices of Bisan Owda and Jenan Matari as examples of digital counterstorytelling and analyze how they challenge the dominant western narrative. While Owda is literally surviving a genocide she manages to share her own personal stories as well as those in Gaza also trying to survive the holocaust. Matari, a storyteller from the diaspora, uses her platform to illustrate the vile depravity of ‘israeli’ society while simultaneously amplifying the voices of Palestinians in her homeland. In the conclusion I include the results of a survey on the concept of “auditioning for humanity,” addressing the October 9th “ceasefire,” and the need to remain vigilant by following the lead of Palestinians as they alone must determine when justice has been applied in a Free Palestine.
Intra- and Inter-Rater Reliability of Features of Movement Commonly Associated with Movement Competency
(University of Waterloo, 2026-01-07) Sen, Dilara
Movement screening tools, such as the Functional Movement ScreenTM and the Movement Competency Screen, are commonly used to assess fundamental movement patterns. These movement patterns, such as squatting and lunging, serve as the foundation for human movement, essential for daily living and athletic performance. By assessing an individual’s ability to control their joints during fundamental movements, screens help identify potential areas for improving performance and reducing injury risk. However, existing screens are limited. They do not adequately assess movement competency, the ability to move competently, without limitation or impairment, under different task demands (e.g., varying loads or speeds). The Physical Literacy ScreenTM (PLS) was developed to more comprehensively assess movement competency. Unlike previous screens, the PLS considers how different task demands (e.g., varying load or speed) influence how movers control key movement features, to inform exercise, education, and coaching recommendations based on a more thorough understanding of an individual’s movement abilities. Because PLS feature scoring relies entirely on visual observation, the reliability of judging these features must be established before the framework can be applied with confidence. Therefore, the purpose of this study is to determine the intra-rater and inter-rater reliability of visually assessing key movement features commonly associated with movement competency. This study examined the reliability of raters visually judging three key movement features, knee control, back control, and shoulder control, using standardized video recordings of athletes performing PLS-derived tasks. Twenty-two kinesiology students independently assessed pre-recorded videos of varsity volleyball athletes and re-scored the same videos at least 14 days later. Intra-rater reliability was measured using Cohen’s Kappa, and inter-rater reliability using Fleiss’ Kappa. Results showed moderate intra-rater reliability for Knee (κ = 0.42) and Back (κ = 0.47) features and fair reliability for Shoulder (κ = 0.28). Inter-rater was poor across all features, with Fleiss’ Kappa values below zero. The study provides initial reliability evidence for the visual judgment of key movement features using PLS-derived tasks. These findings highlight the importance of refining feature definitions, improving rater training and calibration procedures, and clarifying scoring criteria to enhance consistency. Strengthening these elements may support more reliable use of visual movement assessments in sport, education, and health contexts.
Youth Lived Experiences in High-Rise Housing: Implications for Health and Urban Planning
(University of Waterloo, 2026-01-06) Chan, Matthew
Continued global urbanization and the growth of high-rise residential development have increasingly shaped the environments in which young people live. Although related areas of study have examined how built, natural, and social environments influence youth well-being, the health implications of high-rise living for youth remain poorly understood. In the present study, small semi-structured focus groups (2-4 participants) with 19 youths aged 13-18 were conducted, lasting between 63 and 86 minutes. Each focus group was recorded, transcribed, and analyzed using the Framework Method to identify recurring themes. Five themes were developed: Safety and Security; Public Space Design and Accessibility; Social Inclusion and Participation; Economic and Structural Barriers to Youth Needs; and Physical and Mental Health. Youth described both positive and negative experiences within high-rise and high-density environments, associated features such as clean public spaces, social infrastructure, and recreation areas with positive well-being; whereas they identified homelessness, drug use, and poor lighting negatively, which led to avoidance of certain public spaces. A central theme that emerged from the data was youth perceptions of safety and social disorder, indicating that challenges in high-rise environments extend beyond planning and design but also relate to social and environmental conditions. The study contributes to understanding how youth experiences can inform more inclusive and healthier high-rise urban environments.
Exploring the importance of community freezers and a country food box distribution program in the Inuvialuit Settlement Region, Northwest Territories, Canada
(University of Waterloo, 2025-12-23) Yurris, Aimee Caroline
Background: Consuming food harvested from the land, water, and sky (country food) is important for the physical and cultural wellbeing of Inuvialuit. Community freezers are infrastructure intended to support the safe storage of country foods. Further, community freezers have the potential to play a role in food-related programming, such as country food distribution programs. Despite the prevalence of community freezers across Inuit Nunangat, there are few published studies evaluating the implementation and impact of these spaces. Objectives: The specific objectives of this thesis are to describe the use, importance, strengths and barriers, and overall outcomes of the implementation of community freezers in the context of the Inuvialuit Settlement Region, and to describe the importance, strengths, and areas for improvement of the Inuvialuit Community Economic Development Organization country food box distribution program as a program run in connection to community freezers across the region. Methods: Using a qualitative case study design, this project involved semi-structured interviews with community members (n=42) who use the community freezer(s) or could potentially use the community freezer(s) in Paulatuk and Tuktoyaktuk, as well as semi-structured interviews with individuals responsible for managing community freezers (n=7) across Inuvialuit Settlement Region communities. Data were analyzed using reflexive thematic analysis, drawing upon participatory analysis techniques with local community researchers to ensure that results reflect community contexts and realities. Results: The findings describe the importance of freezer space and supplies for storing food (i.e., bins, Ziploc bags, and vacuum sealers) for access to country food, particularly given the number of factors such as cost of gas and equipment that impact community members’ ability to engage in harvesting practices. Despite different community freezer management practices used across the communities of Paulatuk and Tuktoyaktuk, community members in both communities experienced benefits from having and using a community freezer. Such benefits include increased access to freezer space and enjoying increased access to country foods via programs run through the community freezer. Across both communities, community freezers enable the sharing of country foods, enable the storage of larger food items and large quantities of food, and support Inuvialuit culture, way of life, and wellbeing. Challenges with community freezers include lack of communication and awareness about the freezer, reliability of the freezer, ensuring food safety and organization, and the cost and time required for managing and maintaining community freezers. The findings also describe the importance of the Inuvialuit Community Economic Development Organization country food box distribution program. Community members expressed that the country food boxes increase their access to country food and provide support for harvesters who contribute foods to the program. Strengths of the program include the convenience of the foods included in the boxes, variety and the ability to try new foods, and that the program enables the sharing of country food. Suggested areas for improvement include increasing portion size and knowing where and who the harvested foods came from. Conclusion: Reliable and sufficient storage for country foods is an important component of food security in the Inuvialuit Settlement Region. This project has made an important contribution to the literature on the importance of community freezers in the Western Arctic and provides valuable evidence for communities across the Inuvialuit Settlement Region seeking to advocate for additional investment into community freezers. This study also contributes valuable information to the ongoing improvement of the Inuvialuit Community Economic Development Organization country food box distribution program, highlighting both strengths and potential areas for improvement.
Bioptic Telescopic Spectacles and Driving Rehabilitation for People with Age-Related Macular Degeneration: A Pilot Project
(University of Waterloo, 2025-12-23) Khakneshin, Sahar
Introduction Driving is a multifactorial task of which vision is a component. A person’s ability to meet requirements to gain or maintain a driver’s license may be compromised by visual impairments (VI) caused by ocular diseases such as Age-related Macular Degeneration (AMD). However, vision is only one component of safe driving. Programs aimed at permitting and individually assessing a person’s ability to drive are important for improving the quality of life of Canadians living with VI whose ability to safely drive may be in question. Purpose In Ontario in October 2020, the Highway Traffic Act was amended to allow the use of [bioptic] telescopes to meet provincial visual acuity requirements for Class G licensure for the first time. pending successful completion of an on-road driving assessment while using the telescope (MTO Bioptic Telescope Program). The George & Judy Woo Centre for Sight Enhancement (CSE) in Waterloo, Ontario has formulated a training protocol involving both fitting and training with a bioptic telescope for driving. The aim of this study aim was to determine whether the program sufficiently prepares individuals with AMD to effectively use their bioptic telescope, as determined by success in a simulated in-car evaluation. Methods The study aimed to recruit up to 10 participants with AMD who had lost their driver’s license within the last 5 years, met MTO Bioptic Telescope Program visual requirements and did not suffer from motion sickness or cognitive impairment (by self-report). Visual function and visual perceptual testing as well as bioptic telescope fitting were administered. Participants also proceeded into the CSE training program which included 3-5 training sessions and a counselling session. Participants’ driving skills and use of bioptic telescope(s) were then assessed in a virtual reality SUV driving simulator both with and without the telescope. Results Three participants (mean age of 74 years, male) were enrolled and completed the study. Visual parameters met the eligibility criteria (corrected visual acuity ranged from 0.35logMAR (20/50) to 0.77logMAR (20/126), contrast sensitivity ranged from 1.00-1.45logCS units and visual fields were full peripherally). All three participants had binocular central scotomas identified on Humphrey monocular full field tests and Nidek microperimetry. However, no central scotoma was evident on the Humphrey Estermann binocular field assessment. Each participant was fit with a bioptic telescope (2.2-3x magnification) and completed three training sessions. All participants passed the Scan Course but failed the other visual perceptual tests (Useful Field of View, Trail Making, Motor Free Visual Perceptual Test-4). Participant 3 failed the Montreal Cognitive Assessment for the Blind and Visually Impaired. In the final assessment, Participant 1 successfully completed the driving simulation with and without the telescope with no critical driving errors. Participant 2 passed only with the telescope which was used appropriately to identify traffic and speed signs. Participant 3, despite having the best visual acuity, failed under both conditions with critical errors. Conclusion Although further research is required, several important findings to date have been identified. First, the Esterman binocular visual field test cannot be solely used to determine the full field of those with a potential central deficit. Second, the visual perceptual tests conducted with the cut-offs provided, did not definitively identify those individuals that may not be suitable for driving with bioptics; a functional assessment appears to continue to be the gold standard. Third, full medical evaluation should be conducted prior to the visual function evaluation to help identify those that are not safe driving due to non-visual reasons. Finally, it appears that the CSE Bioptic Fitting and Training Protocol may effectively enable participants to learn to apply the fundamental skills required for using a bioptic telescope in a driving situation.
Cues, Clones, and Cars: Access Control Issues in Customized Android
(University of Waterloo, 2025-12-23) Vyas, Parjanya
Android’s open-source design and extensive customization have fueled its dominance across smartphones, automotive systems, wearables, and other domains. This flexibility, however, introduces serious security challenges, particularly in the enforcement of access control. Prior research has investigated inconsistencies within the framework, across layers, and across Android versions, yet important gaps remain, especially in detecting vendor-introduced data-driven customizations, replicated APIs, and platform-specific adaptations (e.g., automotive) that are difficult to capture with existing techniques. This dissertation investigates how Android contextual features can be systematically leveraged to uncover access control vulnerabilities that evade prior analyses. It presents four main contributions: - Bluebird: a probabilistic inference framework that derives access control requirements from application-side sensitivity indicators (UI cues and app-side access control). By fusing NLP-driven signals with static analysis, Bluebird identifies APIs whose protections do not match implied sensitivity. Applied to 14 ROMs, Bluebird flagged 391 likely under-protected private APIs.% and supported 11 proof-of-concept exploits. - Ariadne: a static-analysis based technique built around a novel access control dependency graph abstraction that models explicit and inferred access control relationships among framework data holders. Ariadne detects inconsistencies introduced by data-driven vendor customizations that traditional tools miss. Evaluated on AOSP and vendor ROMs, it discovered 30 unique inconsistencies and enabled 13 proof-of-concept exploits. - RepFinder: a large-scale measurement pipeline that identifies duplicated or ``Replica'' APIs created via copy-paste editing and evaluates their access control enforcement. Analyzing 342 ROMs from 10 vendors, RepFinder found replication to be widespread (~141 Replicas/ROM on average) and that a significant fraction (37% on average) of Replicas are under-protected. - AutoAcRaptor: a platform-specific static analysis framework for AAOS that identifies automotive entry points and evaluates both access control and feature-check enforcement. Applied to 10 AAOS ROMs, AutoAcRaptor reported an average of 23 auto feature and access control anomalies per ROM. Collectively, these contributions show that Android contextual features such as app-side sensitivity indicators, framework data holders, and platform-specific service registrations can be systematically harnessed to reveal overlooked access control vulnerabilities. They also demonstrate that techniques for identifying framework customization-induced vulnerabilities can be adapted to emerging Android-based platforms such as Android Automotive OS by accounting for platform-specific differences. Beyond these immediate contributions, this work opens two broader research directions. First, the contextual features explored in this work may not be exhaustive. Future research should aim to identify additional contextual signals—potentially through automated discovery—and explore an integration framework that makes it easy to incorporate new analyses into a unified solution. Second, the adaptation of these techniques to other Android-based platforms remains an open challenge. While AutoAcRaptor demonstrates feasibility for Android Automotive, other platforms such as Android TV, Wear OS, and Android XR present unique differences that require dedicated investigation to determine how well these methods generalize and what extensions are needed.
Pragmatica: A VR Tool for Autonomous Practice During Language Therapy
(University of Waterloo, 2025-12-23) Prasad, Karthik
Aphasia is a communication disorder that affects millions worldwide, but those affected by aphasia have limited access to in-person therapy. They compensate for this with at-home practice, but existing tools are either ineffective or require a clinician to be present. We present Pragmatica, a VR platform that enables people with aphasia to practice their communication skills independently at home through immersive, context-rich activities. In an eight-week case study, we compared Pragmatica with traditional therapy (4 participants per group). With no detected difference in Quick Aphasia Battery (QAB) scores, VR participants engaged in substantial practice (31 hours, 366 activities) and described the VR experience as engaging, fun, and motivating, but had a limited variety of relevant and unique activities. Our study contributes empirical evidence of VR’s feasibility for autonomous language practice, as well as design insights and considerations for accessible, aphasia-friendly VR systems (flexible controls, multi-modal prompts and inputs).
Understanding International Graduate Students' Housing Experiences.
(University of Waterloo, 2025-12-23) Mohammed, Saluhu
The global rise in international graduate student mobility has intensified housing pressures in host cities, exposing gaps in institutional support and affordable housing provision. In Canada, particularly in Kitchener/Waterloo, Ontario, international graduate students experience growing difficulty securing adequate and affordable accommodation. Despite their financial and academic contributions, this group remains underrepresented in housing policy and planning research. The main problem addressed in this study is the mismatch between increasing international graduate enrolments and the inadequate housing infrastructure and policies designed to meet their needs. Existing research focuses largely on undergraduate student housing or general urban affordability, leaving a significant research gap concerning the lived experiences of international graduate students and the structural factors shaping these outcomes. The study draws on Housing Pathway Theory (Clapham, 2002, 2005) as its primary theoretical framework, emphasizing housing as a dynamic, non-linear process shaped by the interaction between individual agency and structural constraints. To enhance explanatory depth, the study integrates Bourdieu’s conceptual triad of habitus, capita, and field (1984,1986). This combined framework highlights how different forms of capital, economic, cultural, and social interact within the housing field to influence students’ pathways, constraints, and adaptive strategies. Together, these theories explain how international graduate students navigate the tension between structural housing limitations and their personal resources, revealing how inequalities in capital shape distinct housing trajectories. The research employed a mixed-methods, cross-sectional and case study design. Primary data were collected through an anonymous online survey and follow-up interviews to international graduate students who opted to be interviewed. Purposive and snowball sampling yielded 125 valid responses from an initial 136. Quantitative data were analyzed descriptively using SPSS (Version 28) to identify patterns of affordability, accessibility, and housing satisfaction, while qualitative responses underwent thematic analysis using NVivo 15 to interpret lived experiences and coping strategies. The major findings reveal that international graduate students face acute housing precarity, with affordability, discrimination, and limited information networks as central challenges. High rents and the dominance of PBSA developments have marginalized students with limited financial capital. Cultural and social capital strongly influenced housing outcomes: those with local networks or prior Canadian experience navigated markets more effectively. Many respondents reported overcrowded, temporary, or substandard conditions that negatively affected their well-being and academic performance. The findings also expose structural inequalities embedded in municipal housing markets and institutional policies, which privilege domestic or undergraduate cohorts. Policy implication highlights the need for universities, municipal authorities, and provincial housing agencies to develop integrated housing strategies that recognize international graduate students as a distinct and vulnerable demographic. Recommendations include expanding affordable housing supply through university–municipal partnerships, improving access to tenant education and legal resources, and ensuring that institutional housing policies reflect the diversity of students’ economic and cultural needs. By centering international graduate students lived experiences, this study contributes to academic discourse on housing inequality and provides actionable insights for designing inclusive and sustainable student housing frameworks.
Computational Insights into the Corrosion Behavior of NbTaMoW and NbTaMoWV High-Entropy Alloys in Molten Fluoride Salts
(University of Waterloo, 2025-12-23) Katai, Agnes
Molten salt reactors (MSRs), one of the six next-generation nuclear reactor designs, employ molten fluoride salts as the coolant and/or fuel solvent when operated in a thermal-neutron spectrum, and offer higher thermal efficiency compared to today’s water-cooled reactors. Nonetheless, the elevated temperatures, corrosive nature of salts, and high neutron irradiation in MSRs create a harsh environment for structural materials. The influx of impurities, namely moisture, into the molten salt medium has long been shown to exacerbate the corrosivity of fluorides. Owing to their superior thermal and mechanical robustness, refractory high-entropy alloys with a body-centered cubic (BCC) structure have been proposed as candidate containment materials for MSRs. Nonetheless, the degradation of these advanced materials in molten fluorides is an intricate process whose underlying mechanisms remain poorly understood. This study explores the corrosion behavior of BCC (100)-NbTaMoW and (100)-NbTaMoWV surfaces in pure and hydrated FLiBe salt via density functional theory and ab initio molecular dynamics simulations. Electronic structure analyses, including density of states and crystal orbital Hamilton population, provide insight into the interfacial bonding and charge transfer. Irrespective of salt purity, NbTaMoW exhibits minimal d-band shifts which highlight its electronic stability, and weak interactions with fluorine and oxygen. The addition of vanadium to form NbTaMoWV further diminishes susceptibility to oxidation and enhances stability at the salt interface, suggesting superior corrosion resistance in both pure and hydrated salt.

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