Theses

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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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Synthesis of Ta-doped Li7La3Zr2O12 for application in solid-state electrolyte
(University of Waterloo, 2026-04-30) Yan, Xinmei
Solid-state batteries have emerged as a major focus in rechargeable battery research. Among them, cubic-phase of lithium lanthanum zirconium oxide (LLZO) demonstrates excellent room-temperature ionic conductivity, low activation energy, and high thermal stability against lithium metal. Conventional LLZO synthesis struggles with particle size control and large-scale uniform production, limiting commercial applications. Thus, developing an efficient synthesis route for high-quality LLZO is critical. In this work, a refined standard operating procedure (SOP) for fabricating dense pellets from powder was established using commercial powder. Systematic optimization of green body properties and sintering yielded ceramics with 95.8% relative density, 0.49 mS cm⁻¹ conductivity at 20 °C and 0.25 eV activation energy (20–40 °C). Furthermore, the study introduces a spray-drying synthesis approach for cubic-phase Ta-doped LLZO powder. Compared to commercial powders, the synthesized LLZTO produced similarly dense pellets (up to 96.4%) with comparable electrochemical performance. The best sample reached an ionic conductivity of 0.36 mS cm⁻¹ at 20 °C and 0.52 mS cm⁻¹ at 40 °C, with a minimum activation energy of 0.23 eV. Preliminary tests integrated synthesized LLZTO into 3D printing inks. After de binding and sintering, phase stability or crystallite size were unaffected, but mechanical fragility prevented reliable electrochemical testing. Overall, this study demonstrates both an effective spray drying route for scalable LLZTO synthesis and the feasibility of fabricating oxide-based solid electrolytes via 3D printing. Further optimization is needed to improve the mechanical strength and reproducibility of printed structures before achieving consistent electrochemical characterization.
Efficient Inference-time Control and Alignment
(University of Waterloo, 2026-04-30) Rashid, Ahmad
Modern foundation models are typically trained in three broad stages. First, large-scale pre-training is performed using self-supervised learning on massive corpora. Second, models are adapted through mid-training using supervised fine-tuning or instruction tuning on labeled datasets. Finally, a post-training stage is often applied using preference data and reinforcement learning in order to align the model and improve its safety, reliability, and usefulness. Although effective, post-training methods can be computationally expensive and inflexible once large models are deployed. This thesis explores an alternative paradigm: enforcing behavioral objectives at inference time rather than modifying model parameters during post-training. In this approach, smaller modular control models are combined with a base model to shape predictions during the decision process. Our aim is to design alignment mechanisms that are both mathematically grounded and empirically strong while remaining computationally efficient and easy to deploy. We apply this perspective of inference-time control to three problems. First, we address reliability in neural classifiers. We introduce PreLoad, an inference-time mechanism that mitigates arbitrarily high confidence on inputs that lie outside the training support while preserving accuracy and training efficiency. Second, we study reward-guided text generation (RGTG) in large language models as a form of inference-time alignment. We show that stable reward-guided decoding requires carefully designed token-level reward models and propose two algorithms, PARGS and FaRMA, that enable effective reward-guided generation. Third, we address the computational cost of RGTG and propose an efficient algorithm that adds only a minor overhead during inference while preserving the performance and benefits of reward-guided decoding. Together, these results demonstrate that inference-time control provides a flexible and computationally efficient framework for shaping the behavior of modern neural systems. By decoupling representation learning from the decision-time objectives, this work introduces new tools for improving the reliability, alignment, and efficiency of large-scale machine learning models without retraining them.
On Induced Saturation in Graphs and Tournaments
(University of Waterloo, 2026-04-30) Fan, Xinyue
Let H be a graph. A graph G is H-induced-saturated if G is H-free — meaning that no induced subgraph of G is isomorphic to H — and adding or removing any edge in G leaves a graph that is no longer H-free. In this thesis, we study the following question: For which graphs H does there exist an H-induced-saturated graph G? A full answer remains out of reach; indeed, it remains open whether H-induced-saturated graphs exist for every even cycle H. This is particularly intriguing because, in contrast, Behrens et al. [1] gave a short proof that H-induced-saturated graphs exist when H is an odd cycle (except for the triangle, which is complete). A “halfway” result toward settling the case of even cycles is due to Tennenhouse [16], who showed that for every even cycle H, there exists a (non-complete) graph G that is H-free such that adding any edge to G creates an induced copy of H. Tennenhouse’s construction is remarkably simple, but it does not satisfy the edge-deletion property. Our first result complements this: We prove that for every even cycle H, there exists a (non-empty) graph G that is H-free such that deleting any edge from G creates an induced copy of H. The construction of such a graph G is rather involved, and yet unfortunately does not satisfy the edge-addition property. We also study our deletion-only relaxation of induced saturation for other choices of H. In particular, we consider the case where H is a tree, and prove that for every non-complete tree H with two leaves at distance at most three, there exists a (non-empty) graph G that is H-free such that deleting any edge of G creates an induced copy of H. In fact, we prove that every non-complete graph H with two leaves at distance at most three has this property. This follows from an even stronger result for graphs with two leaves satisfying certain technical conditions. Finally, we examine the tournament analog of induced saturation: For which tournaments H does there exist a tournament G that is H-free such that flipping the orientation of any arc of G creates a copy of H? The case where H is transitive is particularly interesting, since Ramsey’s theorem implies that only finitely many H-free tournaments exist in the first place. We prove that for every transitive tournament H, if the critical tournament exists for H, then it also exists for the tournament Δ(1, 1, H), obtained from a cyclic triangle by blowing up one vertex into a copy of H.
Sex- and-Gender-Based Analyses of Penicillin Allergy Labels, Outcomes, and Delabeling Interventions
(University of Waterloo, 2026-04-30) Maximos, Mira
Background: Penicillin allergy labels (PALs) affect approximately 10% of the population, yet over 95% of labeled individuals tolerate penicillin following delabeling interventions. For patients who are considered low risk, oral challenge (OC) and direct delabeling (DD) are increasingly favored over penicillin skin testing (PST), although definitions of low risk vary. Sex-based differences in PAL prevalence and clinical characteristics remain poorly defined. Females are more frequently labeled with penicillin allergy and receive antibiotics more often than males, yet sex-based differences in PAL prevalence, delabeling outcomes, and antibiotic utilization practices remain poorly characterized. A clearer understanding of how sex influences PAL reporting, delabeling strategies, and antibiotic selection is needed to optimize allergy evaluation and antimicrobial stewardship. Objectives: This thesis examined sex-based differences in PAL, delabeling strategies, and antibiotic utilization. A systematic review and meta-analysis evaluated effectiveness and safety of DD and OC in low-risk patients and assessed sex and gender differences in reporting and outcomes. A descriptive analysis characterized OC protocols, hypersensitivity reactions, and reported predictors of adverse events. A cross-sectional study assessed associations between sex and PAL in an ambulatory care hospital in Ontario, including differences in β-lactam allergy reporting, reaction severity, and comorbidities. Finally, a cohort study evaluated whether sex modifies the association between PAL and antibiotic prescribing, including antibiotic class selection and use of second-line agents when β-lactams are indicated. Methods: This thesis is based on research utilizing multiple diverse study designs, including a systematic review and meta-analysis, a descriptive epidemiologic analysis, and cross-sectional and cohort studies. A PRISMA-guided quantitative systematic review was conducted through February 2024 to identify studies evaluating direct delabeling (DD) or oral challenge (OC) in low-risk patients compared with no intervention, penicillin skin testing, or alternative strategies. Study quality was independently assessed by two reviewers. Random-effects meta-analyses were performed, with subgroup analyses conducted in the presence of substantial heterogeneity (I² >75%), and qualitative data were synthesized narratively. Data from included OC studies were further analyzed descriptively to characterize challenge protocols, adverse reactions, and reported predictors of hypersensitivity, with reactions classified by timing and pooled adverse event rates estimated using random-effects models. A STROBE-guided cross-sectional study of adults attending an ambulatory urgent medicine clinic in Ontario (2015–2024) examined associations between sex and penicillin allergy labels (PALs) using multivariable logistic regression. A retrospective cohort study of the same population assessed whether sex modified the association between PAL status and antibiotic prescribing, including antibiotic class selection and β-lactam use when indicated, using multivariable logistic regression with interaction terms; Firth’s bias-reduced methods were applied when separation occurred. Results: Across 28 studies included in the systematic review and meta-analysis (2 randomized trials, 26 quasi-experimental), sex was reported in 86%, with females comprising 61% of participants; however, only 18% disaggregated outcomes by sex and no studies reported gender variables. OC was similarly effective to PST in randomized trials (RR 1.04, 95% CI 0.95–1.13), while quasi-experimental studies reported high delabeling rates for OC (~90%). Direct delabeling was possible in approximately 27% of those included with a study arm for DD. A descriptive epidemiologic analysis of 26 OC studies demonstrated a pooled reaction or non-delabeling rate of 4% (95% CI 3–6%), most commonly mild cutaneous reactions, with higher baseline allergy burden and shorter intervals since index reaction being identified as potential risk factors. In a cross-sectional study of 29,645 ambulatory care patients in Ontario, 9.4% had a penicillin allergy label (PAL), most of which were low risk; females were significantly more likely to have a PAL than males, report multiple medication allergies, and demonstrate sex-specific associations between PAL and comorbidities. In multivariable analysis, female sex, atopic disease, older age, and number of other medication allergies were independently associated with PAL. In the cohort study, PAL was independently associated with increased antibiotic use, while female sex was associated with lower odds of antibiotic prescribing. Effect modification by sex was not detected between PAL and antibiotic use, class selection, or guideline-recommended therapy. Conclusion: PALs remain common and are disproportionately reported among females, despite high tolerability of penicillin following evaluation. Low-risk delabeling strategies, particularly OC, are safe and effective, yet sex- and gender-disaggregated outcomes are infrequently reported limiting understanding of clinical implications. Although female sex was independently associated with PAL and distinct comorbidity patterns, sex did not modify the relationship between PALs and antibiotic utilization. These findings highlight persistent gaps in sex- and gender-sensitive evidence across the management of patients presenting with infections that have a PAL.
Use of Steel Fibres in Bridge Decks to Improve Serviceability and Reduce Top Mat Reinforcement Requirements
(University of Waterloo, 2026-04-30) Rezaee, Bibi Saida
This study examined a practical strategy to enhance the long-term performance of bridge deck slabs, which are highly susceptible to deterioration due to corrosion of conventional steel reinforcement. While glass fibre reinforced polymer (GFRP) bars offer corrosion resistance, their low stiffness often necessitates increased reinforcement ratios to meet serviceability requirements, diminishing their economic and practical benefits. To address this limitation, the study investigated the use of steel fibre reinforced concrete (SFRC) with steel macrofibres to improve service performance and reduce top mat reinforcement demands. The research program integrated concrete mixture development, material characterization, and large-scale structural testing. Practical SFRC mixtures were developed to evaluate material properties including workability, compressive strength and direct tensile response to support mixture selection for structural testing. Six large-scale one-way bridge deck slab strip specimens were tested to failure, simulating deck overhang behaviour. The test variables included GFRP reinforcement ratios of 0.6% and 0.8% and steel fibre volume fractions of zero, 0.5%, and 1.0%. A conventionally steel reinforced slab without fibres served as a control. The results demonstrated that the incorporation of steel fibres significantly improved crack control, stiffness, and flexural capacity in GFRP reinforced slabs. Fibre reinforced specimens exhibited service and strength performance comparable to or exceeding that of the steel-reinforced control slab, with improvements increasing with fibre dosage. Notably, comparable serviceability was achieved even with reduced flexural reinforcement when steel fibres were present. Collectively, the findings indicated that SFRC can effectively mitigate the serviceability limitations of GFRP reinforcement enabling more durable, efficient, and lower maintenance bridge deck construction.
Ahsan Hdeyeh 3ana
(University of Waterloo, 2026-04-30) Jabbour, Sandra
Ahsan Hdeyeh 3ana consists of a series of large-scale India ink paintings on fabric, that stem from my experience as a second-generation Lebanese-Syrian woman born in Canada. This body of work references my familial archive of VHS home videos from the late 90s and early 2000s, encompassing my childhood in Canada and my parent’s life in Syria and Lebanon, to depict themes of cultural in-betweenness, family dynamics, memory, and multilingualism. Notably, this work centers on my childhood as it was recorded on these VHS tapes which were later sent to my family members in the Middle East so that they could watch my brother and I grow up despite the geographical distance. Even though I have not met many of them face-to-face, the exchange of these video tapes fostered a close family relationship between myself and my relatives. As VHS tapes deteriorate overtime, my paintings capture some of the memories contained in this forgotten media, while also allowing me to recontextualize imagery from the past and the present, reflecting on my diasporic connection to my Syrian-Lebanese identity.
The effect of exotic species on native species reintroductions: Ontario's lake trout reintroductions
(University of Waterloo, 2026-04-30) Therrien, Christian
Reintroduction programs are important tools for reversing extirpations of fishes in freshwater environments, but only 25-50% of reintroduction programs are successful. Exotic species are present in many habitats that are targeted for restoration, and exotic species can negatively affect reintroduced species through predation, competition, and changes in the quantity and/or quality of available prey. Thiamine (vitamin B1) is an important nutrient in the diet of fishes. There is growing concern that consumption of thiaminase, an enzyme that degrades thiamine and is found in the exotic prey fish rainbow smelt (Osmerus mordax), may be impacting reintroductions of lake trout (Salvelinus namaycush) in lakes where they are present. Ongoing programs to reintroduce lake trout in Ontario, specifically in the Sudbury Basin and Lake Ontario, provide an opportunity to study how the outcome of reintroduction efforts is influenced by (1) the presence of exotic rainbow smelt; and (2) identity of source population (with specific focus on previous exposure to exotic prey species). I used a multi-lake study to determine if presence of exotic rainbow smelt resulted in decreased tissue thiamine concentrations in lake trout and compared fish body condition and growth between lakes that do and do not contain rainbow smelt. I found that while muscle thiamine concentrations of lake trout did not differ between lakes with and without rainbow smelt, an instance of thiamine deficiency was observed in a lake that contains rainbow smelt. I also found that body condition was significantly lower in lake trout from lakes with rainbow smelt and the asymptotic length of lake trout populations declined with increasing proportion of smelt in the diet. My results suggest that consumption of exotic rainbow smelt can cause thiamine deficiency, decrease body condition and lower asymptotic length in lake trout, and ultimately may be a factor contributing to the failure of programs to reintroduce lake trout throughout Ontario. Next, I compared the effects of diets designed to mimic the thiaminase activity of exotic prey fishes, including rainbow smelt, on survival and performance-related traits between two hatchery strains (Seneca Lake and Slate Island) of lake trout that differ in historical exposure to diet-derived thiaminase. Results indicated that, regardless of strain, the diet containing thiaminase negatively affected most performance-related traits and while most of the negative effects of the thiaminase diet did not differ between the two strains, an increase in red pigmentation and decrease in survival was observed in Seneca Lake fish that had received the thiaminase diet. By comparing the response of two hatchery strains of lake trout to a diet containing thiaminase, I found evidence that pre-existing adaptations to thiaminase differ among hatchery strains of lake trout. Of the hatchery strains I examined, the Slate Island strain is the best environment match and is likely the most suitable for reintroduction into lakes where exotic prey fishes occur. Lastly, I captured a fish of presumed wild origin from Tyson Lake, which has been subjected to reintroductions of lake trout since the 1970s but previously had no records of natural reproduction. Using a combination of methods, I confirmed the fish was, indeed, of wild origin and represents the first documentation of natural reproduction in Tyson Lake. The fish was assigned to both the Lake Manitou and Iroquois Bay strains, which suggests that these two strains of lake trout may be best suited for reintroduction into lakes in the Sudbury Basin, due to their ancestry match to extirpated populations of lake trout in the area. By incorporating multiple methods, this thesis identifies some of the major factors influencing the success of reintroductions of lake trout and advances our understanding of best practices for species reintroductions.
Process Intensification of Sustainable Production Systems through Integrated Modeling and Optimization
(University of Waterloo, 2026-04-30) Roth, Taylor
This thesis aims to advance the sustainability of emerging resource production processes through the application of process intensification and integrated modeling and optimization techniques. Two process optimization frameworks are developed and tailored for the optimization of sustainable agriculture and aviation fuel production processes, which are applied through case studies. The first study develops an optimization framework to determine optimal operating strategies in monoculture and polyculture hydroponic systems considering uncertainty and disturbances. A key novelty of this work is the development of a polyculture hydroponic model incorporating interspecies nutrient interactions and dynamic environmental factors into the optimization problem, offering insights for system management and sustainability. Mechanistic nutrient uptake and growth models are validated using experimental data to effectively capture system dynamics, and used to improve resource efficiency while accounting for parameter uncertainty and external disturbances. A case study of hydroponic polyculture soybean and tomato plants demonstrates the benefits of this approach. Results show that hydroponic systems increase yield by over 60% compared to traditional farming. Compared to monoculture hydroponics, polyculture methods reduce nitrogen consumption by 40% and increase annual profit by 3.91% per kilogram of fruit. These findings highlight the importance of nitrogen supply management and demonstrate how computational optimization can advance sustainable agriculture. The second study determines optimal process designs of intensified catalytic distillation (CD) columns for Alcohol-to-Jet (ATJ) sustainable aviation fuel (SAF) production to improve aviation sector sustainability. Sequential CD columns with separate oligomerization and hydrogenation reactions are compared to a fully intensified CD column with simultaneous reactive sections. Although prior studies emphasize the importance of ATJ kinetic modeling, validated models and experimental data remain limited. Accordingly, a first-order kinetic model containing 46 parameters is developed using experimental data and a genetic algorithm to support the SAF CD model. A key contribution is the application of an enhanced parallel hybrid deterministic–stochastic algorithm (eHDSA) for the optimization of SAF CD systems with multiple reactive sections and integer decision variables, including the quantity and location of reactive stages. The eHDSA is modified from prior work to improve performance for complex SAF optimization problems, achieving average total annualized cost (TAC) reductions of 40% compared to a purely stochastic approach. Replacing two sequential CD columns with a single intensified column yields TAC reductions exceeding 86%, with sensitivity analyses indicating strong design robustness. Results demonstrate that CD intensification can reduce capital and energy requirements, improving resource efficiency and environmental sustainability for SAF production within the ATJ pathway.
Understanding Diverse Needs for Justice: The Role of NGOs in Advocating for Victims/Survivors of Wartime Sexual Violence in the Occupied Territories of Ukraine
(University of Waterloo, 2026-04-30) Iovenko, Marianna
Since Russian armed aggression against Ukraine began in 2014, conflict-related sexual violence (CRSV) has been systematically employed against the Ukrainian population, yet the institutional response has remained structurally misaligned with what survivors actually need. This thesis examines how NGO-based service providers and survivor-led networks (SLNs) in Ukraine conceptualize and respond to CRSV survivors’ justice needs, and what their accounts reveal about the failures of the state’s retributive approach. Drawing on ten semi-structured interviews with representatives of Ukrainian NGOs and SLNs, alongside critical discourse analysis of institutional documents, organizational reports, and government forms, the thesis identifies three interconnected findings. First, the bureaucratic architecture through which the Ukrainian state recognizes CRSV survivors functions as a mechanism of institutional betrayal: survivors are required to translate their experiences into administrative categories designed for different forms of harm, and the formal CRSV survivor status adopted in November 2024 has yet to produce any viable pathway to support. Second, Ukrainian civil society organizations have become the primary providers of care in the space the state has failed to fill, but their donor-dependent, fragmented structure cannot substitute for sustained state provision. The emergence of SLNs represents a qualitative shift in this fragmented landscape of care, as survivors move from beneficiaries to rights-holders demanding meaningful participation in policymaking. Third, survivors’ self-defined understandings of justice diverge significantly from the retributive model the state prioritizes: rather than punishment as an end in itself, survivors seek acknowledgment, transformation from passive victim to active agent, and holistic support that addresses present material and social needs. Together, these findings advance a survivor-defined model of justice that reframes the demand for state accountability not around prosecution outcomes but around recognition and reintegration on survivors’ own terms. The thesis contributes the first empirically grounded analysis of Ukrainian CRSV survivors’ justice needs developed through a feminist sociolegal framework and interview-based methodology, filling gaps that both domestic criminological scholarship and Western feminist legal critique have left unaddressed.
Weyl's Equidistribution Theorem in function fields and multivariable generalizations
(University of Waterloo, 2026-04-30) Champagne, Jérémy
This thesis is concerned with the problem of finding a satisfactory function field analogue to Weyl's Equidistribution Theorem, a task that was initiated by Carlitz in 1952. More specifically, we are looking at the equidistribution of polynomial values $f(x)$ as $x$ runs over the ring $\mathbb{F}_q[T]$, where $f(X)$ is a polynomial with coefficients taken from $\mathbb{F}_q\big((T^{-1})\big)$, the field of formal Laurent series in $T^{-1}$. Classically, results of this type were restricted to the case where the degree of $f$ is less than $p:=\text{char}\,\mathbb{F}_q$, and this \textit{characteristic barrier} was broken about a decade ago by L\^e, Liu and Wooley using new developments surrounding Vinogradov's Mean Value Theorem. Here, we resolve a remaining conjecture made by L\^e, Liu and Wooley, thus establishing the largest class of equidistributed polynomial sequences $f(x)$ determined by irrationality conditions on the coefficients of $f(X)$. We also consider further generalisations of the resulting theorem, which we phrase in terms of additive polynomials related to $f(X).$ In any case, the main difficulty that we encounter arise from some possible interference occurring between terms of the form $\alpha X^k$ with those of the form $\beta X^{p^\upsilon k}$ appearing in the expansion of $f(X)$. To avoid problems of this type, we introduce a transformation $f(X)\mapsto f^\tau(X)$ which preserve the size of Weyl sums, and has the property that $f^\tau(X)$ does not involve any terms of the form $\beta X^{pk}$. In a different but related direction, we generalize the method of L\^e, Liu and Wooley for multivariate polynomial sequences $f(x_1,...,x_d)$ where $(x_1,...,x_d)$ run over $\mathbb{F}_q[T]^d$, and we also consider the case where each of $x_1,...,x_d$ is required to be monic. Similarly to the original paper, the method consists in establishing a minor arc estimate for multivariate Weyl sums using the Large Sieve Inequality together with a multivariate version of Vinogradov's Mean Value Theorem in function fields obtained previously by Kuo, Liu and Zhao.
Love is (not) a Woman’s Topic. Images of Femininity in the Context of Romantic Relationships in Works by Contemporary German-speaking Female Authors
(University of Waterloo, 2026-04-30) Owtscharenko, Sophie Theresa
This thesis examines the representation of femininity and romantic love in contemporary German-language literature, focusing on three works: Miroloi by Karen Köhler, Hey guten Morgen, wie geht es dir? by Martina Hefter, and Die schönste Version by Ruth-Maria Thomas. It analyzes how romantic relationships shape female identities and how these representations are reflected, questioned, and reworked in the selected literary texts. The study is based on the assumption that romantic love functions as a central cultural narrative that influences female life models and contributes to the stabilization of social norms. The thesis shows that all three works engage critically with established models of femininity and romantic love. While the texts differ in tone and structure, they each illustrate how female identities are shaped in relation to romantic relationships and how these frameworks can be challenged or transformed. Overall, the study demonstrates that contemporary German-language literature contributes to an ongoing discussion about femininity, love, and social ex-pectations.
School-Based Youth Sport-for-Development Programs in Ontario: Current Practices and Future Directions
(University of Waterloo, 2026-04-30) Barber, Melanie
This study examined the implementation and future directions of sport-for-development (SFD) programs within Ontario elementary schools, addressing a notable gap in the literature, which has largely focused on community or international contexts while leaving school-based SFD underexplored. Drawing on Ecological Systems Theory and Positive Youth Development (PYD), the study aimed to understand how SFD is integrated into school sport environments, the objectives guiding these initiatives, their perceived impacts, and the supports necessary to enhance program effectiveness. A mixed-methods approach was employed, including survey data from 84 participants across 43 school boards and semi-structured interviews with educators and program volunteers involved in SFD programming. Quantitative data were analyzed descriptively to identify patterns in program use, while qualitative data were analyzed using reflective thematic analysis to explore experiences and perceptions of program delivery. Findings indicate that many schools engage in practices aligned with SFD principles; these efforts are often lacking formal recognition or educator training. Programs were founded to prioritize social and emotional development, including leadership, confidence, belonging, and positive peer relationships, and were perceived to positively influence overall school culture. However, inconsistencies in resources, limited professional development, and gaps in structured partnerships with external organizations presented challenges to sustainable implementation. This study contributed to the literature by providing one of the first comprehensive examinations of SFD within Canadian elementary schools, highlighting the need for intentional program design, increased educator training, and stronger coordination across schools, school boards, and community organizations. Theoretically, it extends PYD by emphasizing belonging not only as an outcome but as a critical precondition for PYD within school-based sport programs. Offering insights for both practice and future research in SFD implementation.
Cultivating a Community Corridor: A Reimagination of Welland’s Public Space
(University of Waterloo, 2026-04-30) Giammarco, Marisa
Cultivating a Community Corridor examines the decline of the core, main street and public space of the once-thriving industrial town of Welland, Ontario. Welland’s downtown has diminished in its use and community profile over the past fifty years, stemming from major shifts in the city’s economy and landscape. The introduction of the Welland Canal bypass in the 1970s made the existing canal, which passed through the city centre, redundant. In turn, a reduction in industrial employment led to a slowly growing population and vacant main streets. A design solution that expands public space and evokes the site’s collective memory aims to revitalize this significant city. Downtowns embody the true nature of a city where community, culture, and history converge in a central area. Commonly seen throughout Canadian mid-sized cities, including Welland, downtowns are losing their identity. This is due to population decline, poor urban design, or economic challenges posed by competition from car-dependent suburban businesses. With Welland’s population expected to increase significantly over the next 25 years, creating sufficient public space for both current and future residents is essential to the city’s success. This thesis envisions a thoughtful revitalization of Welland, using the decommissioned canal as a central corridor, with a focus on placemaking and strengthening public identity. Lessons from successful projects in other cities guide the creation of a design that addresses existing barriers and orients the proposal within space. An in-depth look at Welland’s history reveals its rich transportation heritage, use of local materials, and notable buildings. The project aims to craft a space that fosters community, celebrates local culture, and uncovers the layers of history embedded within the site. It concentrates on designing public spaces along Main Street and the Welland Canal. Strategic design approaches foster a stronger sense of community and a deeper connection to history by serving both current needs and future growth. The urban development of public space and the downtown core leads to densification, economic growth, and integrated attractions, supporting Welland’s population growth and shaping its identity.
Dual-Scale Finite Element and Machine Learning Framework for Predicting Effective Inelastic Deformation of Unidirectional Non-Crimp Fabric Composites Considering Manufacturing-Induced Defects
(University of Waterloo, 2026-04-30) Zeng, Yu
High performance composite materials, particularly carbon fiber reinforced polymer (CFRP) composites based on unidirectional non-crimp fabric (UD-NCF) reinforcements, have gained widespread adoption in aerospace, automotive, and wind energy industries due to their exceptional specific stiffness, strength, and design flexibility. However, the mechanical performance of UD-NCF composites is strongly governed by complex manufacturing induced microstructural features and defects, including irregular fiber geometries, non-uniform fiber dispersion, in-plane fiber misalignment, and out-of-plane fiber crimping, which arise inherently from the fabric architecture and liquid resin infusion processes. These microstructural complexities introduce significant variability in effective mechanical properties, posing substantial challenges for accurate property prediction. The inherent complex multiscale structure of UD-NCF composites must be considered when predicting mechanical properties, where finite element (FE)-based approaches are preferred. However, the high computational cost of repeated high fidelity FE simulations across multiple length scales renders conventional multiscale approaches impractical for design optimization, sensitivity analysis, and uncertainty quantification. Addressing these limitations requires a computationally efficient, physically informed multiscale framework that explicitly incorporates realistic microstructural features while remaining tractable for engineering applications. The focus of this thesis was to develop a scalable multiscale computational framework integrating finite element (FE) homogenization and machine learning (ML) surrogate modelling to accurately predict the effective elastic properties and strain rate dependent inelastic behaviour of UD-NCF composites, while explicitly accounting for realistic microstructural features and manufacturing induced variability. The first objective was to develop a hierarchical dual scale FE homogenization framework explicitly incorporating key manufacturing induced microstructural features quantified through systematic microscopic characterization. Microscale representative volume elements (RVEs) captured fiber geometry, spatial dispersion, and resin distribution, whilst mesoscale models incorporated tow geometry, inter tow spacing variability, in-plane fiber misalignment, and out-of-plane fiber crimping. Microscale fiber distribution and diameter variability had negligible influence on mean elastic properties for sufficiently large RVEs, whilst RVE size significantly affected prediction variance. Microscale predictions showed strong agreement with Chamis' analytical formulations, with moderate discrepancies in shear properties at lower fiber volume fractions. At the mesoscale, in-plane misalignment exerted a pronounced influence on the longitudinal modulus and in-plane Poisson's ratio, whilst out-of-plane crimping had minimal effect at small angles. The framework predicted longitudinal and transverse elastic moduli within 1% of experimental measurements, with approximately 20% deviation in the in-plane shear modulus attributed to uncertainties in fiber shear properties and microstructural variability. The second objective was to develop an automated data generation pipeline and train ML surrogate models to establish quantitative elastic structure-property relationships for the UD-NCF composite material at both length scales. Neural network and XGBoost models trained on systematically generated FE datasets achieved mean R² values exceeding 0.97 at the microscale and 0.99 at the mesoscale, with mean absolute percentage errors consistently below 1.5%, reducing prediction times from hours to seconds. SHAP based interpretability analysis confirmed that the surrogate models captured physically meaningful structure property relationships consistent with established micromechanical theory. The third objective was to extend the multiscale framework to predict strain rate dependent inelastic behaviour of UD-NCF composite by integrating established physical constitutive formulations into the surrogate modelling workflow, addressing a key gap in data driven composite modelling where inelastic deformation behaviour has received comparatively limited attention. Neural network and XGBoost surrogate models were trained on FE RVE datasets incorporating systematic variations in microstructural parameters, including in-plane fiber misalignment, with the FE framework showing strong agreement with experimental inelastic and strain rate dependent responses, confirming its suitability as a data generation tool. An automated RVE generation and post-processing pipeline provided a scalable foundation for efficient dataset construction. Incorporating physical formulations, namely the Johnson Cook strain rate model, Hill's anisotropic yield criterion, and power law hardening, into the data engineering process substantially reduced training data requirements, constrained the solution space, and improved model generalizability, enabling accurate prediction of complex inelastic and strain rate dependent behaviour across a wide range of loading rates. Collectively, this work establishes a scalable, computationally efficient digital twin framework bridging microstructural variability and macroscopic composite performance. By explicitly accounting for manufacturing induced microstructural features and integrating high fidelity FE homogenization with data driven surrogate modelling, the developed methodology provides a practical tool for accelerating multiscale modelling, virtual prototyping, sensitivity analysis, and design optimization of UD-NCF composite systems under realistic manufacturing conditions, representing a significant step towards physics informed digital twins for next generation composite structural applications.
The Effects of Lumbar Extensor Muscle Fatigue on Trunk Neuromuscular Control during Medio-Lateral Perturbations in Male and Female Contact-Collision Athletes
(University of Waterloo, 2026-04-30) Bossom, Juliana Grace Ludvig
Trunk neuromuscular control is commonly assessed using sudden external perturbations to elicit unexpected instability, enabling the evaluation of stabilization strategies through trunk kinematics and muscular responses. Previous analyses focus on sagittal plane loading to assess these responses, with many studies exploring how the trunk responds in a dysfunctional state, such as muscular fatigue. Despite relatively inconsistent findings across literature, a general idea has emerged that the trunk’s stabilizing system will compensate for the loss of the force production associated with muscular fatigue to maintain trunk kinematic response, limiting extreme ranges of motion. However, most investigations primarily assess neuromuscular control in the sagittal plane, leaving the effect of muscle fatigue on frontal plane trunk neuromuscular control less understood. Additionally, a limited focus on between-sex comparisons in trunk neuromuscular control research represents an important knowledge gap, due to previously reported sex-differences in trunk kinematics during dynamic tasks and potential differences in fatigue characteristics. Given the generation of moments to oppose frontal plane loading is inherently more complex than those in the sagittal plane, and frontal plane sudden loading occurs in many dynamic sports, this work aims to characterize the effect of lumbar muscle fatigue on the response to sudden medio-lateral (M-L) perturbations between sexes. It was hypothesized that the trunk neuromuscular control system will prioritize task performance and joint safety through maintaining spine angular displacement, while compensating through decreasing time to peak velocity and increasing muscular activation peaks, with males having higher peaks than females. It was further hypothesized that muscle onset latencies will not vary with fatigue, since altering muscular activation is likely more favourable in response to decrease force producing capabilities. Twenty-eight (14M, 14F) contact-collision athletes experienced bidirectional M-L perturbations before and after low back muscle fatigue, in a randomized order. Participants were positioned in a semi-seated apparatus restricting lower-extremity motion with cables connecting a chest harness to a pulley-load supporting system with no external pre-loading. Perturbations were elicited through an unexpected drop force applied to the trunk on one side, equivalent to 30% of lateral bend strength. Spine angular displacement and muscle activation dynamics, including activation peak and onset latency, were used to understand trunk response to sudden loading. Muscles assessed included bilateral lumbar erector spinae (LES), thoracic erector spinae (TES), rectus abdominus (RAB), internal (INO) and external obliques (EXO). The first right and left trials of each fatigue condition were used for statistical analysis, and responses were assessed within an approximate 2 second window following perturbation onset. Generalized linear mixed models (GLMM) of the gamma log family were used to evaluate the effects of fatigue and sex on trunk kinematic and muscle activation dynamics variables. No differences in spine angular displacement were present while fatigued, yet notable neuromuscular compensations were found through condition-sex interactions. When fatigued, males exhibited greater bilateral LES activation, demonstrating sex-specific compensatory trunk control strategies. Across conditions and sexes, the abdominal musculature, particularly INO, had the highest peak activation and shortest onset latencies, suggesting an important role in frontal plane trunk stabilization. These results advance the understanding of frontal plane trunk neuromuscular control under fatigue and support the need for future work exploring sex-specific trunk stabilization strategies and their implications for training and injury risk.
Below, Above, and Beyond: Reimagining Integration of an Equitable Podium Level of Transit-Oriented Communities
(University of Waterloo, 2026-04-30) Zeng, Celia
This thesis proposes an investigative framework for designing transit-oriented podiums to facilitate their integration into the transit-oriented communities (TOCs) they serve in Toronto. Transit is essential to the daily lives of more than two million Canadians and is key to a city’s economic growth. In Canada, where 81.5% of Canadians commute by car, transit-oriented developments (TODs) are a high priority in the core areas of major communities to foster social diversity, reduce urban congestion, and lower carbon emissions. Here, the transit-oriented podium plays a critical role in supporting the successful implementation of TOCs. The typology serves as the key connector among transit commuters, tower residences, and the existing community context, shaping the public realm. However, the current typical building podium design is often static and repetitive. This is often due to how the podium design is approached, given the typology’s inherent nature to be generic, gridded, and easily repurposed, resulting in a lack of consideration of the podium’s future programmatic occupants during the early design phases. The research proposes a framework for redefining the approach to podium design through an urban and building design case study on two proposed TOC sites of markedly different scales along the Ontario Line in Toronto, Ontario: Pape Station and Thorncliffe Park. The research examines contemporary developments in podium configuration, including the influence of policymaking, urban connectivity, and program allocation. Site-specific analysis is required to understand the different approaches to each site. The integration of a transit-oriented podium at Pape Station is being considered on a smaller scale. Rather than a TOC, the podium proposed at Pape Station serves as the anchor for a future TOC, with speculation about its future densification given its proximity to other stations on the Bloor-Danforth line. Thorncliffe Park, on the other hand, is approached at a larger scale, with a series of podiums proposed, as it is already a well-defined community. The proposed designs focus on the connection of the podium and its immediate surroundings and are not concerned with large-scale connectivity between transit stops. This includes the podium’s connection to the immediate transit infrastructure, the circulation among tower residents, transit users, and podium occupants, and program allocation based on their accessibility and visibility requirements for success, and the needs of the community it serves. The thesis presents designs in the investigative and schematic phase to establish a proof of concept for the proposed framework. Pape Station and Thorncliffe Park are only two of the many neighbourhoods in Toronto planned for rapid densification around transit hubs. While each transit station may share similarities, the communities they serve are all different. The thesis stresses that the design approach for podiums is site-specific, and the framework’s flexible approach could inform future transit-oriented podium design.
NeuralOS: Towards Simulating Operating Systems via Neural Generative Models
(University of Waterloo, 2026-04-30) Rivard, Luke
We introduce NeuralOS, a neural framework that simulates graphical user inter- faces (GUIs) of operating systems by directly predicting screen frames in response to user in- puts such as mouse movements, clicks, and keyboard events. NeuralOS combines a recur- rent neural network (RNN), which tracks computer state, with a diffusion-based neural renderer that generates screen images. The model is trained on a large-scale dataset of Ubuntu XFCE recordings, which include both randomly generated interactions and real- istic interactions produced by AI agents. Experiments show that NeuralOS successfully renders realistic GUI sequences, accurately captures mouse interactions, and reliably pre- dicts state transitions like application launches. Although modeling fine-grained keyboard interactions precisely remains challenging, NeuralOS offers a step toward creating fully adaptive, generative neural interfaces for future human-computer interaction systems.
Tracing Footsteps: Ritual, Place-Making, and Negotiating Identity in Italian-Canadian Processional Landscapes
(University of Waterloo, 2026-04-30) Simonetta, Giulia
This thesis examines how Italian patron-saint processions operate as spatial practices that shape community identity across geographic and cultural contexts. At its core, it asks how ritual movement transforms urban space into meaningful place, and how these practices are carried, adapted, and sustained through migration. Focusing on two case study processions from Calabrian towns – San Nicola da Crissa and Torre di Ruggiero – and their diasporic counterparts in Ontario, the research traces the continuity of these traditions as they move between homeland and diaspora. The study employs a multi-layered methodology combining archival research, oral histories, photographic analysis, and architectural drawing. Through plan obliques and detailed vignettes, processional routes are mapped and analyzed revealing the relationships between bodies, ritual objects, and the built environment. The findings show that processions do more than move through space, they transform it. Streets, piazzas, and neighbourhoods become temporarily redefined as sites of devotion, memory, and collective presence. At the same time, these rituals operate as place-making practices and transnational anchors, reproducing the logics of the hometown within new urban forms – where churches take on the role of piazzas, and statues become fixed markers of diasporic identity. In diasporic contexts, processions adapt to local conditions, reshaping their routes, soundscapes, and ceremonial rhythms while continuing to carry the traditions of their places of origin. In this way, they create what can be understood as “double towns,” where past and present, here and elsewhere, are held together through movement. The thesis concludes that architecture extends beyond static form, emerging instead through the relationships between people, movement, and place. Through procession, communities actively produce space as lived and meaningful, demonstrating how identity, memory, and belonging are not only preserved, but continually made and remade across landscapes and generations.
Late Paleoproterozoic ocean redox history from sedimentary thallium and uranium isotopes and implications for eukaryotic evolution
(University of Waterloo, 2026-04-29) Kunert, Alexandra
The most complex domain of life on Earth, eukaryotes, may have evolved as early as ~2.7 billion years ago (Ga), but the timing and trajectory of their evolution is not well understood nor are the environments in which they evolved. As most modern eukaryotes are aerobic, molecular oxygen (O2) may have played an important role in the development and proliferation of early eukaryotes. However, this is an area of continued debate. The oldest evidence for eukaryotic life lies in the ~1.8 Ga sedimentary rock record as organic-walled microfossils which have been counted and classified to determine their abundance and diversity. However, O2 cannot so readily be accounted for in the rock record. Instead, geochemical redox proxies—chemical signatures resulting from interactions with O2—can be employed to deduce past environmental conditions. At ~1.8 Ga, the Earth’s atmosphere may have been weakly oxygenated, and the oceans may have been stratified into weakly oxygenated surface waters, anoxic (O2-free) and sulfidic (euxinic) mid-depths and anoxic and ferruginous (Fe2+-rich) deep waters. However, details about the areas in which the earliest known eukaryotes inhabited remain vague. Here, uranium (U) and thallium (Tl) isotopes in fine-grained, organic-rich sedimentary rocks of the late Paleoproterozoic—some of which host eukaryotic microfossils—are used to determine the extent of marine productivity along continental margins ~1.84 Ga (U isotopes) and if oxygenation was occurring within an intracontinental basin ~1.78–1.64 Ga (Tl isotopes). Ultimately, these findings provide a better understanding of the environments in which the earliest known eukaryotes inhabited. In the modern oceans, seawater U isotope compositions (δ238Usw) respond to changes in the areal proportions of seafloor covered by oxic, anoxic and euxinic bottom waters. Isotopic fractionation primarily occurs in anoxic/euxinic environments during U(VI)→U(IV) reduction, where the reduced sedimentary phase preferentially retains the heavier 238U and seawater preferential retains the lighter 235U. Because of this, at times of greater oxygenation like today where oceans are oxygenated throughout with only small areas of anoxia, δ238Usw (–0.38‰) is similar to the composition of incoming rivers (–0.29‰). In the Proterozoic when oceans featured ferruginous anoxic deep waters, euxinic continental margin mid-depths, and a thin oxic surface layer, it is expected that δ238Usw would be much lighter. However, Proterozoic carbonates, which approximate δ238Usw at the time they were deposited, are not significantly different from modern. This is resolved with new U isotope data from ~1.84 Ga across a drillcore transect in the Animikie Basin (North America) which features black shales deposited from low-O2, ferruginous and euxinic bottom waters. Unlike carbonates which differ from δ238Usw only by a minor diagenetic effect, black shale δ238U may be heavier than δ238Usw as a result of reductive isotopic fractionation. The heaviest δ238U recorded in the Animikie Basin are found in highly productive (high total organic carbon, TOC) euxinic and ferruginous mid-depths (0.15 ± 0.14‰) and dynamic environments at the redoxcline (0.39 ± 0.16‰). In contrast, low-O2 environments near the shoreline and low-TOC ferruginous environments on the deep shelf in the basin featured light δ238U (–0.10 ± 0.25‰) close to the river input composition. These findings reveal that a widely anoxic ocean can yield δ238Usw near-modern if much of it was low-TOC ferruginous deep waters with minimal isotopic fractionation and only small areas on continental margins with highly productive euxinia had large isotopic fractionations. This is useful for quantifying the level of Proterozoic primary productivity, as times with lighter δ238Usw could signify an expansion of highly productive margins. This is observed at ~1.84 Ga in the carbonate record, which indicate enhanced primary productivity triggered by nutrient input from continental weathering or large igneous province volcanism. A large primary productivity signal with no currently known examples of eukaryotes at ~1.84 Ga could be indicative of dominantly anoxygenic photosynthesis that could have suppressed the development of early aerobic eukaryotes. Thallium isotopes in seawater (ε205Tlsw) respond to the amount of manganese (Mn) oxide burial under well-oxygenated bottom waters. The heavier 205Tl isotope is preferentially adsorbed to and oxidized by Mn oxides and seawater preferentially retains the lighter 203Tl isotope. Thus, at times with expansive oxygenation and Mn oxide burial, as at present, ε205Tlsw (–6‱) is lighter than ocean inputs (–2‱). This can be harnessed for ancient ocean oxygenation reconstruction because under most reducing conditions (low-O2, anoxia, euxinia), black shales and organic-rich mudrocks will directly record contemporaneous ε205Tlsw. In the McArthur Basin (Australia), shales from the ~1.78–1.73 Ga Tawallah Group and ~1.65–1.64 Ga McArthur Group reflect ε205Tlsw in an intracratonic basin (not the global ocean) that cover a range near modern input compositions to modern ε205Tlsw: –2.1‱ to –5.5‱. All geological units studied feature sample groups with ε205Tl near input composition (averaging –2.6‱ to –2.9‱), called ‘baseline’ groups which represent periods of minimum intracratonic basin oxygenation. Periods of isotopic excursion to lighter ε205Tlsw were also recorded in each unit from averages of –3.7‱ to –5.2‱, reflecting periods of expanded intracratonic basin oxygenation. Some of the oldest eukaryotic microfossils are found in the McArthur Basin at ~1.78 Ga and ~1.65 Ga, although often these are found in the locally low-O2 or anoxic environments seen in the studied drillcores. These may therefore be stem group eukaryotes which evolved to live in lower O2 conditions but were not direct ancestors to modern aerobic eukaryotes. However, the presence and periodic expansion of oxygenated environments may have harboured aerobic eukaryotes that have yet to be discovered.
A Sensor Fusion Platform for Semantic Segmentation of Outdoor Ice Scenes
(University of Waterloo, 2026-04-29) Duan, Richard Rui Jia
Due to climate change and global warming, Arctic sea ice coverage has been on a downwards trend that is expected to continue late into this century, opening up new shipping routes through the Arctic. These routes provide opportunities for much shorter transoceanic journeys compared to currently used routes, offering significant savings in transportation time and resource cost. However, travelling through ice-covered waters still provides a constant source of risk from collisions with ice damaging or even sinking the vessel. Thus, modern tools such as ice charts, satellite imagery, and near-field observations from on-board experts are still used to avoid dangerous collisions with ice. In adverse weather and lighting conditions, near-field human observations can be uncertain, causing inaccuracies in determining nearby ice conditions. This thesis introduces a system composed of an optical RGB camera, a thermal infrared camera, and a polarization camera to aid in such near-field observations for the purposes of determining nearby ice conditions in a variety of outdoor conditions. The novel sensor suite was tested during field trials conducted in February 2025, collecting river ice data across multiple days and at different locations along the Ottawa and St. Lawrence rivers. After image registration and post processing, a first-of-its-kind, fully labelled semantic segmentation dataset of 118 images across 5 scenes was created to test different methods of sensor fusion. For testing, the test set was further split into easy and hard subsets based on perceived clarity to the human eye. Early, middle, and late fusion networks using different combinations of sensor inputs were created based on modifying the widely used fully convolutional neural network U-Net architecture with a pre-trained ResNet-18 backbone. Experimental results show that early fusion methods performed consistently worse than the baseline case of only using the optical RGB data on both the easy and hard test sets, regardless of the other input sources used, most likely due to the higher levels of noise being introduced by the additional sources. Middle fusion with polarization and thermal managed to outperform the baseline on the hard test set, and late fusion with polarization managed to outperform on the easy test set. While both middle and late fusion methods show improvements over the baseline through extracting useful information even from noisy sources, late fusion with polarization had the highest overall mIoU improvement on the full test set due to an enhanced ability to differentiate between brash ice and water. Ultimately, sensor fusion shows potential for improving sea ice classification accuracy while being robust to a variety of different environmental and lighting conditions. These preliminary results serve to support continued development of sensor fusion platforms as tools to aid in the tracking and identification of nearby ice conditions.

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