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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Municipal Wastewater Sludge as a Sustainable Bioresource: Spatial Analysis Across Ontario
(University of Waterloo, 2025-10-08) Granito Gimenes, Camila
Effective wastewater sludge management is critical for sustainable wastewater treatment, nutrient recovery, and environmental protection. However, Ontario lacks in data of sludge generation and nutrient content, particularly across diverse facility sizes and treatment processes. This study aims to fill that gap by estimating wastewater sludge generation, nitrogen and phosphorus content, and disposal practices across 548 municipal wastewater treatment plants (WWTPs) in Ontario. Using a combination of facility-level annual reports, the Wastewater Systems Effluent Regulations (WSER) database, Ontario Clean Water Agency (OCWA) records, and National Pollutant Release Inventory (NPRI) was developed treatment-specific coefficients from a subset of plants with complete data to extrapolate sludge generation, nitrogen and phosphorus mass for facilities lacking direct data. For the year 2022, the most recent year with complete data, Ontario’s WWTPs generated an estimated 356,265 ± 35,859 dry metric tons of sludge, with a per capita generation of 23.5 kg/person/year falling within the range reported in the literature (17.8–31.0 kg/person/ year). Nutrient content analysis revealed median concentrations of 29 kg/ metric tons of dry sludge for phosphorus and 42 kg / metric tons of dry sludge for nitrogen, resulting in an estimated 9,937 ± 1,837 metric tons of phosphorus and 15,302 ± 9,044 metric tons of nitrogen generation per year in wastewater sludge. Over 50% of the nutrients are concentrated in larger, anaerobic digester-equipped facilities, located primary in Southern Ontario. Incineration accounts for the end-use of 30% of the total sludge generated, resulting in the loss of their nutrients. In contrast, agricultural disposal, practiced by 140 facilities, allows for nutrient recovery from 26% of total sludge generated. Spatial and process-level analysis revealed that plant size and stabilization method are predictors of disposal type. Large plants (defined with influent (≥ 37,850 m3/day), which are more likely to operate aerobic or anaerobic digesters, tend to adopt more sustainable disposal methods when conditions permit (e.g. during appropriate seasons). In contrast, small facilities (with influent (≤ 3,785 m3 /day) often lack in advance stabilization and are more likely to rely on less sustainable practices such as landfill. Many of these facilities also lack consistent reporting, making it difficult to track sludge generated and disposal pathways. By quantifying the generation of sludge and nutrient flows across Ontario, this study provides a baseline for evidence-based decision-making. The data can be used by municipalities and regulators to identify areas with high biosolids generation, data gaps, and to target specific regions for further study or investment. These findings highlight the need for provincial-level data transparency and target strategies to promote nutrient circularity in municipal sludge management, particularly by addressing the data and resource gaps at smaller facilities. While this study provides a valuable province level overview, a key limitation is the reliance on extrapolation data or facilities lacking complete records, underscoring the need for improved, standardized reporting and new methodologies with more data in the future.
Using eye tracking to study the takeover process in conditionally automated driving and piloting systems
(University of Waterloo, 2025-10-08) Ding, Wen
In a conditionally automated environment, human operators are often required to resume manual control when the autonomous system reaches its operational limits — a process referred to as takeover. This takeover process can be challenging for human operators, as they must quickly perceive and comprehend critical system information and successfully resume manual control within a limited amount of time. Following a period of autonomous control, human operators’ Situation Awareness (SA) may be compromised, thus potentially impairing their takeover performance. Consequently, investigating potential approaches to enhance the safety and efficiency of the takeover process is essential. Human eyes are vital in an individual’s information gathering, and eye tracking techniques have been extensively applied in the takeover studies in previous research works. The current study aims at enhancing the takeover procedure by utilizing operators’ eye tracking data. The data analysis methods include machine learning techniques and the statistical approach, which will be applied to driving and piloting domains, respectively. Simulation experiments were conducted in two domains: a level-3 semi-autonomous vehicle in the driving domain and an autopilot-assisted aircraft landing scenario in the piloting domain. In both domains, operators’ eye tracking data and simulator-derived operational data were recorded during the experiments. The eye tracking data went through two categories of feature extractions: eye movement features linked predominantly to fixation and saccades, and Area-of Interest (AOI) features associated with which AOI the gaze was located. Eye tracking features were analyzed using both traditional statistical techniques and machine learning models. Key eye tracking features included fixation-based metrics and AOI features, such as dwelling time, entry count, and gaze entropy. Operators’ SA and takeover performance were measured by a series of domain-specific metrics, including Situation Awareness Global Assessment Technique (SAGAT) score, Hazard Perception Time (HPT), Takeover Time (TOT) and Resulting acceleration. Three research topics were discussed in the current thesis and each topic included one driving study and one piloting study. In topic 1, significant differences in eye movement patterns were found between operators with higher versus lower SA, as well as between those with better and worse takeover performance. Besides the notable differences in various Area-of-Interests (AOIs) across three pre-defined Time windows (TWs), in the driving domain, drivers with a better SA and better takeover performance showed inconsistent eye movement patterns after the Takeover Request (TOR) and before they perceived hazards. In the piloting domain, pilots with shorter TOT showed more distributed and complex eye movement pattern before the malfunction alert and after resuming control. During the intervening period, their eye movements were more focused and predictable, indicating fast identification of necessary controls with minimal visual search. In topic 2, significant differences in eye movement patterns were observed between younger and older drivers, as well as between learner and expert pilots. As for driving domain, older drivers exhibited more extensive visual scanning, indicating difficulty in effectively prioritizing information sources under time pressure. In piloting domain, expert pilots not only allocate more attention to critical instrument areas but also dynamically adjust their scanning behavior based on the current tasks. In topic 3, machine learning models trained on eye tracking features successfully performed binary classification for both SA-related and takeover performance related metrics. Model performance was evaluated using standard classification metrics, including accuracy, precision, recall, F1-score, and Area Under the ROC Curve (AUC). Finally, comparisons were made across Topics 1 and 2, as well as between the driving and piloting domains. The results suggest that better operators can flexibly adapt their gaze strategies to meet task demands, shifting between broad visual scanning and focused searching when appropriate. This shift in patterns underscores the importance of accounting for the specific Time window (TW) when interpreting operators’ eye movements. Overall, this thesis advances the understanding of different eye movement patterns during the takeover process by exploring a range of eye tracking features. The findings support the development of operator training programs and the design of customized interfaces to enhance the safety and efficiency of takeover performance.
Artisanship in a post-industrial present: A physio-biological framework for restorative design artifacts
(University of Waterloo, 2025-10-08) Clouthier, Derrick
digital fabrication clay extrusion printing 3D printing psychology restorative design environmental psychology biophilic design biophilia clay Over billions of years, organisms have evolved from single cell organisms into the human species of today. That process shaped the physiology and psychology of the human species. While each person is unique, a product of each individuals experiences and specific genetic endowments, there exists universal features that are innate in the biology of humans. One aspect of this is our brain, a unique organ which has evolved through thousands of generations, and through countless interactions with our environments into a mechanism for our species survival. This evolutionary process created a deep innate relationship between humanity and our natural environments. When modernism emerged at the turn of the 20th century, it fundamentally changed architecture. The economics of mass production mingled with advancements in medical reasoning to produce an architecture of efficiency. Architects such as Adolf Loos, Le Corbusier, and Alvar Alto translated the sterility and medical principles of the sanatorium into housing and beyond, producing an architecture founded on the principles of air and light as essential elements to health, while peeling architecture away from the “humid ground where disease breeds” as defined by Le Corbusier. Large windows, rooftop terraces, and spotless interiors crafted light filled spaces and spotless environments, perfect for the air and sun cure against tuberculosis, but which increasingly separated individuals from the ground humans have evolved to thrive in. Architecture shed the rich visual complexity, naturalistic illusions, and fluid interior exterior relationships of historic architectures, replacing it with a sterile incubator, targeted toward contemporary concepts of health. Modernist architectural advancements led to a sterility that has permeated modern architectures, producing a cognitive discord that is actively harmful to individuals. Researchers in neuroscience and environmental psychology have sought to understand this discord, producing studies which seek to better identify the underlying cognitive mechanisms that inform these interactions. Designers in turn have developed frameworks for applying this research to design for well-being. This thesis proposes a framework for restorative design principles, and advocates the harnessing of digital fabrication technologies to produce restorative artifacts for well-being. Through the development of a framework specifically tailored to the production of digitally fabricated artifacts, this thesis proposes a methodology for generating restorative environments through informed design. The artifacts presented in this thesis demonstrate the application of restorative principles through digitally fabricated artifacts, advocating the adoption of a new architectural language for restorative, evolutionarily informed design.
Approaching Memorization in Large Language Models
(University of Waterloo, 2025-10-08) Cheng, Xiaoyu
Large Language Models (LLMs) risk memorizing and reproducing sensitive or proprietary information from their training data. In this thesis, we investigate the behavior and mitigation of memorization in LLMs by adopting a pipeline that combines membership inference and data extraction attacks, and we evaluate memorization across multiple models. Through systematic experiments, we analyze how memorization varies with model size, architecture, and content category. We observe memorization rates ranging from 42% to 64% across the investigated models, demonstrating that memorization remains a persistent issue, and that the existing memorization-revealing pipeline remains valid on these models. Certain content categories are more prone to memorization, and realistic usage scenarios can still trigger it. Finally, we explore knowledge distillation as a mitigation approach: distilling Llama3-8B reduces the extraction rate by approximately 20%, suggesting a viable mitigation option. This work contributes a novel dataset and a BLEU-based evaluation pipeline, providing practical insights for research on LLM memorization.
Perceptions of Dementia among Young Arab Adults in Ontario
(University of Waterloo, 2025-10-06) Al-Saghier, Ruah
Introduction As dementia rates are projected to rise among ethnic communities in Canada, understanding how these communities perceive the condition is increasingly important (Alzheimer Society of Canada, 2024). This study focuses on young Arab adults due to the Arab population's rapid growth and relatively young age profile in Canada (Statistics Canada, 2022; Canadian Arab Institute, 2019). Given cultural expectations around caregiving, many of these individuals may assume caregiving roles for relatives with dementia in the future. Their perceptions are therefore critical, as they can influence caregiving approaches and help-seeking behaviors. While international studies suggest that Arab communities may hold negative views of dementia (Brijnath et al., 2021; Kane et al., 2021; Abojabel & Werner, 2019), there is limited research exploring these perceptions within the Canadian context. Objective The objective of this qualitative study is to explore the perceptions of dementia among young adults between the ages of 18 and 30 who are members of Arab communities in Ontario. The research question is ‘how do young Arab adults perceive dementia?’. Methods This study recruited 10 young Arab adults and conducted in-depth, semi-structured interviews with each participant. Although the participants were provided with the choice of having an Arabic or English interview, all the participants opted for an English interview. Two interviews were conducted in-person and eight were conducted online. The study used reflexive thematic analysis to analyze the data using a software called MAXQDA. Findings Three themes were generated from the reflexive thematic analysis. The themes provided an idea on how the participants and their communities perceive dementia. The three themes were: Describing dementia, Understanding the causes of dementia, and Living with dementia. The themes shared a range of different perceptions, which may be a reflection of the differences between the participants and their communities. The participants highlight many perceptions that were rooted in religious or spiritual beliefs – highlighting the importance of religion to the community. Overall, many perceptions reflect some stigma in how participants and their community view dementia, such as the hesitancy to use the word dementia or the negative language used to talk about dementia. Implications This study shows the value of developing dementia resources that are both culturally and spiritually sensitive for Arab communities. Involving community members in co-creating educational tools, working with places of worship, and acknowledging the role of cultural beliefs in shaping care can help make public health efforts more effective. As for future researchers, there is a pivotal need to include Arabs living with dementia in Canadian research.
Forbidding odd K3,3 as a graft minor
(University of Waterloo, 2025-10-06) Reinert, Nathan
A graph is odd−K5 free if K5 cannot be obtained by deleting edges and then contracting all edges in a cut. odd − K5 free graphs play an important role in the study of multi-commodity flows. A graph is odd − K3,3 free if K3,3 cannot be obtained by contracting edges and then deleting all edges in an eulerian subgraph. A long-standing conjecture of Paul Seymour predicts that postman sets pack in odd − K3,3 free graphs. We study odd − K3,3 free graphs that are almost planar in this thesis and discuss the relation to Seymour’s conjecture.
Analysis of Heterogeneities in a 20 L Bioreactor
(University of Waterloo, 2025-10-02) Kang, Danny
Biological systems are utilized in various industries to produce valuable products, including biopharmaceuticals. This is done in bioreactors, which are specialized vessels that are able to precisely control key parameters, including agitation, air flow, temperature, pH, dissolved oxygen, and nutrient supply. With the high demands for biopharmaceuticals caused by advancements in medicine, the need for efficient production and optimization of bioreactors has been evident. This has been especially seen during the COVID-19 pandemic, and the high costs of some products, which are inaccessible to many individuals. To optimize production, simulation models have been developed to predict effective control schemes for high growth and product yield. However, this is challenging to translate between lab-scale and industrial-scale due to the formation of gradients in industrial-scale systems, which have poor mixing. Gradients lower the efficiency of bioreactors as cells must constantly adapt to changing extracellular conditions, which cause stress and lower yields. Thus, it is necessary to validate simulation models using the gradients formed in large-scale bioreactors; however, this data is not readily available, and it is difficult to obtain such gradients in smaller-scale bioreactors. In this work, fed-batch experiments are studied to investigate the formation of gradients in dissolved oxygen, kLa, pH, cell density, glucose, and acetate concentrations. This was done through the movement of sensors, turning the air on and off, and the usage of different sampling locations. The objectives of this work were first to characterize the culture with flask and batch experiments and then to use this information to carry out the fed-batch experiments to explore the potential of measuring these gradients. Dynamic metabolic responses were observed and measured depending on the control of the glucose feeding, and consistent gradients were observed for the dissolved oxygen, pH, and kLa, while gradients for cell density, glucose, and acetate were not observed, which may be due to limitations in sampling times. Finally, the metabolic responses have been modeled using modified Monod kinetics, where the modifications include self-growth inhibition, an acetate metabolic switch, and a cell density-dependent lag function. This work was done using a genetic algorithm on Python to optimize parameters, and the model was able to adapt to the different extracellular conditions presented in the fed-batch experiments.
Quantum Data Processing Inequalities and their Reverse
(University of Waterloo, 2025-10-02) Natarajan, Shreyas
Any reasonable measure of quantum information must satisfy a data processing inequality, that is, it must not increase under the action of a quantum channel. The same is, therefore, true for measures of distinguishability of quantum states. In this thesis, we study two families of distinguishability measures that are particularly interesting: the Riemannian metric (more precisely, the corresponding semi-norm) and the standard quantum f-divergences (sometimes referred to as just standard f-divergences). However, rather than focusing on the information lost, we ask about the information preserved - namely, a reverse data processing inequality. As is established in this thesis, an exact reverse data processing inequality for all states acted on by a specific channel is not possible for these measures if the output dimension of the quantum channel is no greater than the input dimension (which includes several important channels). Instead, we settle for a reverse data processing inequality on a restricted set of input states, or oftentimes it suffices to only compare the loss of information incurred via two given quantum channels in general. This thesis demonstrates cases of a restricted reverse data processing inequality for these measures and initiates a study of the similarities between the Riemannian metrics and standard quantum f-divergences in this context.
The Racialization of Land: An Ontological Investigation into 'Settler-Becoming' and Land Racialization
(University of Waterloo, 2025-10-01) MacDonald, Ethan
This thesis is concerned with an ontological premise about the genesis of the settler, and what settler-being implies for the development and dispossession of land. It argues that the racialization of land produces what is known as the settler-being, a distinct ontology developed by the archetypal Settler within the settler colony. This Settler views capitalist private property and elimination as fundamental characteristics that produce the subject as the Settler and is thus the consequence of varying colonial phenomena. Private property and capital accumulation in the context of North American settler colonialism reveal a tendency within the settler-colonial project to ap-ply the characteristics of racialized capitalism towards the land, which settlers seek to colonize and ‘settle,’ thus revealing the subsequent process of racializing the land that they seek to control. Understanding the land as racialized helps make sense of tendencies within settler-colonial society, as the role that private property plays within the continent reveals the role that white supremacy plays in colonization, in capitalism, and settler-colonial ontology.
Enhancing Social Learning in Humanoid Robots Taught by Non-Expert Human Teachers
(University of Waterloo, 2025-09-30) Aliasghari, Pourya
Tools that assist with daily tasks are valuable. For example, with the aging population in Canada and worldwide, there is a growing demand for ways to help older adults perform daily activities independently. Socially intelligent robots can promote independence by assisting with routine tasks. While advanced robots may be capable of performing various specialized operations, it is not feasible for their designers to program them in advance to effectively carry out multi-step, complex tasks requiring high-level planning and coordination, `out of the box' in new environments and for users with diverse preferences. To successfully integrate into domestic environments, robots must learn new task knowledge from human users. Many of our own skills as human beings have been acquired through social learning, i.e., learning via observation of or interaction with others, throughout our lifetime. Social learning for robots enables the transfer of skills without the need for explicit programming, allowing users to teach robots via natural, intuitive, and interactive methods. This thesis targets three key challenges in the social learning of robots: enabling non-expert humans to teach robots without external help, enabling robots to learn and perform multi-step tasks, and enabling robots to identify the most suitable teachers in their social learning. The first phase of my research examines whether or not participants with no prior experience teaching a robot could become more proficient robot teachers through repeated human-robot teaching interactions. An experiment was conducted with twenty-eight participants who were asked to kinesthetically teach a Pepper robot various cleaning tasks across five repeated sessions. Analysis of the data revealed a diversity in non-experts' human-robot teaching styles in repeated interaction. Most participants significantly improved both the success rate and speed of their kinesthetic demonstrations after multiple rounds of teaching the robot. The second phase introduces a novel, biologically inspired imitation approach enabling robots to understand and perform complex tasks using high-level programs that incorporate sequential regularities between sub-goals that a robot can recognize and achieve. To learn a new task, the system processes demonstrations to identify multiple possible arrangements of sub-goals that achieve the overall task goal. For task execution, the robot determines the optimal sequence of actions by evaluating the available sequences based on user-defined criteria, through mental simulation of the real task. This learning architecture was implemented on an iCub humanoid robot, and its effectiveness was evaluated across multiple scenarios. In the third phase, I propose an attribute for identifying the most suitable teachers for a robot: human teachers’ awareness of and attention to the robot’s limitations and capabilities. I investigate the impact of this attribute on robot learning outcomes in an experiment with seventy-two participants who taught three physical tasks to an iCub humanoid robot. Teachers’ awareness of the robot’s visual limitations and learning capabilities was manipulated by offering the robot’s visual perspective and by placing participants in the robot’s position when labelling actions in demonstrations. Participants who could see the robot’s vision output paid increased attention to ensuring that task objects in their demonstrations were visible to the robot. This emphasis on attention resulted in improved learning outcomes for the robot, as indicated by lower perception error rates and higher learning scores. I also propose a metric for robots to estimate the potential for receiving high-quality demonstrations from particular human teachers. These findings demonstrate the feasibility of non-experts adapting to robot teaching through repeated exposure to human-robot teaching tasks, without formal training or external intervention, and also contribute to understanding factors in human teachers that lead to better learning outcomes for robots. Furthermore, I propose a robot learning approach that accommodates variations in human teaching styles, enabling robots to perform tasks with greater flexibility and efficiency. Together, these contributions advance the development of multifunctional and adaptable robots capable of operating autonomously and safely in human environments to assist individuals in various daily activities.
Remote Object Pose Estimation for Agile Grasping: Leveraging Cloud Computing through Wireless Communication
(University of Waterloo, 2025-09-30) Zamozhskyi, Oleksii
As industry transitions toward Industry 4.0, the demand for agile robotic systems capable of vision-guided manipulation is rapidly increasing. However, the computational limitations of onboard hardware make it challenging to support advanced perception pipelines, particularly those based on deep learning. Offloading perception to the cloud presents a promising alternative but introduces latency and reliability challenges that can compromise the real-time performance required for closed-loop robotic control. This thesis presents a robotic grasping system capable of agile, 6D pose-aware manipulation of moving objects by offloading perception to a remote inference server. RGB-D data is continuously streamed over a wireless link to the server, where a deep learning model estimates the object's 6D pose. The estimated pose is then sent back to the robot, which uses it to generate a trajectory for executing the grasp. The system was evaluated on a conveyor-based pick-and-place task under four different wireless network types: Wi-Fi at 60 GHz, Wi-Fi 5 at 5 GHz, 5G NSA at 24 GHz, and 5G NSA at 3.5 GHz. A total of 392 trials were conducted to analyze grasping success rates and the impact of network latency and reliability on performance. The results demonstrate the feasibility of performing agile, closed-loop robotic grasping with cloud-offloaded 6D pose estimation over wireless networks. They also reveal limitations of current wireless infrastructure and deep learning models. The findings suggest that lower-latency, more reliable communication, along with more intelligent local control strategies and faster, generalizing models, are required for production deployment.
ReSlide: Towards Effective Presentation Authoring for Evolving Narratives and Contextual Constraints
(University of Waterloo, 2025-09-29) Zeng, Linxiu
Authoring slides for a public presentation requires speakers to navigate multiple contextual constraints that directly shape how content is structured and delivered. We first conducted a formative study with ten experienced presenters to understand what constraints are prioritized and how they influence slide deck creation. We identified three key constraints---time, audience, and communicative intent---and challenges in integrating them into slide authoring for a single presentation and long-term needs with diverse narratives. We designed ReSlide, a presentation authoring tool that helps presenters create and reuse slides by bridging contextual constraints with evolving narratives. We evaluated ReSlide in a within-subjects study with 12 participants against a baseline tool, and in an exploratory study with eight professional presenters using only ReSlide. Results indicate that Reslide's novel features of constraint awareness and multi-granular slide reuse helped presenters effectively craft presentations in both one and multiple authoring cycles.
The Social Impact of Mining on Children: A Case Study in the Gobi Desert of Mongolia
(University of Waterloo, 2025-09-29) Batbayar, Battumur
Abstract Mongolia is considered the most mining-dependent country in Asia. Sandwiched between China and Russia, mining plays a central role in Mongolia’s economy and development strategies. While the country enforces environmental impact assessment law, the absence of a law for social impact assessment in large-scale projects leaves critical gaps in understanding the effects of mining on vulnerable populations, particularly children. The Gobi Desert in Mongolia is rich in minerals such as coal, gold, and copper, yet highly vulnerable to desertification and climate change, and hosts most of the country’s major mining operations. This case study, situated in the Gobi Desert, examines the social impacts of mining on children in two distinct populations: mining employees working under fly-in, fly-out (FIFO) arrangements, and nomadic herders residing in mining host communities. Employing a mixed methods approach consisting of survey questionnaires and semi-structured interviews, this research aims to unpack the lived experiences of these communities and address regulatory and policy gaps. The study is guided by two objectives: (1) to understand the social context and identify the social impacts of mining on the target populations, and (2) to explain these impacts by analyzing the underlying factors that shape them. The findings indicate that the types of social impacts experienced by children of mining employees and those of nomadic herders are distinct, shaped by differing contextual factors. For children of mining employees, impacts are primarily influenced by income and parental absenteeism: the former enables higher wages and access to better education, while the latter leads to challenges such as disrupted parental involvement and communication breakdowns. In contrast, for children of nomadic herders, key shaping factors include: (1) Corporate Social Responsibility - through local consultations, infrastructure development, and support for social services; (2) environmental conditions - manifested in air pollution and groundwater depletion; (3) migration - characterized by population influx, economic stimulation, and increased child safety concerns; and (4) lifestyle - particularly the threats of displacement and restrictions on the traditional mobility of nomadic herders. These findings contribute to the academic literature on mining and social sustainability while offering practical recommendations for policymakers, highlighting the often overlooked voices of vulnerable communities, such as affected children and families.
Food Environments Influence on Food Choices Among Different Socioeconomic Groups
(University of Waterloo, 2025-09-29) Campbell, Josephine
There has been a shifting focus in research within food security studies to food environments as they are proving to be one of the most influential factors in individuals' food and dietary choices. Situated within the second United Nations (UN) Sustainable Development Goal of Zero Hunger, this thesis examines the physical and social food environments of communities in Hamilton, Ontario to determine the influences these environments have on food and dietary choices. Hamilton was chosen due to its unique food landscape; where some communities could be considered living in a food swamp, with little access to healthy food amidst an abundance of convenience stores and fast food. In contrast, other communities within the city are considered a food oasis, with a wide range of high-quality foods readily available. This study employed a survey as its primary research instrument with 204 surveys completed. In addition, follow-up interviews with 20 participants were conducted to provide in-depth context for the survey results. Participants in this study were drawn from areas based on either postal code or income. The study’s findings revealed several similarities irrespective of the postal code or income of the household. Notably, the most popular dietary choice was that the participants did not follow any diet, also called the “house diet.” Moreover, in ranking the most important qualities when choosing a grocery store, price, proximity, and quality always ranked the highest among the 13 options. However, when reasoning for rankings were discussed, the higher-income participants expressed maximizing their dollars whereas the lower-income participants preferred stretching their dollars. Moreover, looking at food environments grouped by postal code, 7 out of the 19 participants lived in areas where convenience stores outnumber grocery stores at a ratio of 4:1. In these communities, most participants reported a meat-restricted diet and also ranked accessibility to healthy foods the lowest. Additionally, participants living in areas described as food swamps (high prevalence of low-quality convenience foods), also reported lower than average income compared to participants living in areas with better access to higher-quality food retailers. These finding demonstrate that income plays a consequential role in observed dietary patterns, with 7% of the higher income earners reporting a plant-based diet, compared to 20% of the lower income bracket. In the lower income bracket, 42% reported using alternate modes of transportation to private vehicles, compared to only 8% in the higher income bracket. The findings suggest a chain reaction, where the lower-income earners are more likely to be living in a food environment with low access to healthy foods, and high access to convenience stores. Furthermore, they are less likely to have access to a vehicle, which overall limits their accessibility to healthy, fresh, and sustainable food choices that may be some distance from where they live. These are areas where policies, initiatives, and programs that will promote better accessibility to healthy foods will be the most beneficial, in terms of creating healthy eating patterns that will help achieve Sustainable Development Goal Two.
Examining the Association between Functional Social Support, Marital Status, and Memory in Middle-Aged and Older Adults in Canada: A Mixed Methods Study
(University of Waterloo, 2025-09-29) Haghighi, Paniz
Although several studies have found that functional social support (FSS) promotes memory through stress-buffering mechanisms, the role of marital status in shaping this association remains underexplored. This thesis – a sequential explanatory mixed-methods study – is the first research to examine whether marital status modifies the association between FSS and memory in community-dwelling, middle-aged and older adults (45-85 years old). Data for the quantitative portion of the study were obtained from the Tracking Cohort of the Canadian Longitudinal Study on Aging (CLSA). Memory was regressed on FSS, adjusting for various sociodemographic, lifestyle, and health-related covariates, in a linear mixed effects model. The moderating effect of marital status was assessed by adding its interaction with FSS to the model. Results showed significant and positive adjusted associations for overall FSS (β: 0.07; 95% CI: 0.01, 0.13) and two FSS subtypes, namely positive interactions (β: 0.06; 95% CI: 0.01, 0.11) and affectionate support (β: 0.05; 95% CI: 0.00, 0.11), with memory. However, the interaction between marital status and FSS (overall and subtypes) was not statistically significant (likelihood ratio test p-value = 0.75), indicating that FSS did not have differing effects on memory according to marital status. Two sensitivity analyses – one stratifying the sample by baseline marital status and another comparing different missing data approaches – confirmed the initial findings. For the qualitative portion, semi-structured interviews were conducted with a sample of 18 community-dwelling adults who resembled the CLSA population and reported different categories of marital status. Each interview was audio recorded, transcribed verbatim, and thematically analyzed with the goal of explaining and contextualizing the quantitative results. Three major themes emerged from the interviews to help explain why marital status, contrary to a priori expectations, did not impact the FSS-memory association: “learning to cope” – participants used other alternatives besides a spouse to deal with memory challenges; “context matters” – contextual factors such as marital quality may affect this association; and, “doing more harm than good” – some spouses may provide too much support, reducing participants’ autonomy to stimulate their own cognitive processes. The thesis findings highlight the complexity of marital relationships and emphasize the need to consider factors such as satisfaction with one’s marital status and adequacy of support to provide a comprehensive understanding of how social and marital dynamics impact cognitive trajectories. This research suggests public health initiatives focused on enhancing social support could promote cognitive health in aging populations, regardless of marital status.
Synthesis and Analysis of Daptomycin Analogues
(University of Waterloo, 2025-09-26) Brill, Robert
Daptomycin (Dap) is a naturally occurring, membrane-active, calcium-dependent cyclic lipodepsipeptide antibiotic (cLPA) which is used as a last-resort antibiotic to treat serious infections caused by Gram-positive (G+) bacteria including Staphylococcus aureus (S. aureus) and vancomycin-resistant enterococci (VRE). The appearance of Dap-resistant (Dap-R) bacteria with increasing frequency has motivated the search for Dap analogues that are active against Dap-R bacteria. Recently, it has been shown that appending hydrophobic groups to tryptophan (Trp) or kynurenine (Kyn) yielded some Dap analogues with improved activity and were active against Dap-R bacteria. Chapter 2 of this thesis describes the synthesis and evaluation of Dap analogues with hydrophobic modifications to the side chain of the D-asparagine (Asn) residue at position 2 to determine if appending hydrophobic groups to D-Asn2 will also result in Dap analogs with improved activity. Eight Asn derivatives were synthesized containing alkyl or hydroxyl groups appended to the primary amide nitrogen of the D-Asn side chain. Dap analogues containing these D-Asn derivatives at position 2 were synthesized using Fmoc (9-fluorenylmethyloxycarbonyl) solid-phase peptide synthesis (SPPS). Dap analogs containing methyl (Me), ethyl (Et), n-propyl (Pr), n-butyl (Bu) and n-hexyl (Hex) on the D-Asn exhibited minimum inhibitory concentration (MIC) values that were 2–4-fold higher than Dap while the n-octyl (Oct) and piperidinyl (Pip) analogs had MIC values that were 8- and 32-fold greater than Dap, respectively. These results demonstrate that the activity of Dap cannot be improved by appending hydrophobic groups to D-Asn2 and suggest that D-Asn2 may not be closely associated with the cell membrane. These results also show that the primary amide of D-Asn2 is not essential for activity while the presence of at least one hydrogen on the nitrogen of the D-Asn2 side chain is very important to activity. Membrane insertion studies using model membranes and fluorescence spectroscopy revealed that the hexyl and octyl analogues were able to insert into membranes even in the absence of Ca²⁺ consistent with their much-increased hydrophobicity compared to Dap. In chapter 3, we wished to determine if it is possible to convert Dap into a Zn+2-dependent antibiotic by substituting the two aspartate (Asp) residues in Dap’s calcium-binding motif, Asp7 and Asp9, with Nγ-hydroxyasparagine (Asn(OH)), an amino acid that has a hydroxamic acid side chain. Hydroxamic acids, known for strong Zn²⁺ chelation, have been used in medicinal chemistry to improve metal-dependent interactions. The synthesis of an Asn(OH) building block with the hydroxamic acid side chain protected with a trityl (Trt) group (Fmoc-Asn(OTrt)-OH) was achieved following a multi-step route starting from Fmoc-Asp(tBu)-OH. Attempts to synthesize Dap analogues containing Asn(OH) at positions 7 or 9 using this building block via Fmoc SPPS failed. However, the synthesis of a Dap analogue containing Asn(OH) at position 2 was successful indicating that incorporation of this residue using this building block is sequence dependent. A new Asn(OH) building block containing a protecting group that is smaller than the Trt group, the dimethoxybenzyl (DMB) group (Fmoc-Asn(ODMB)-OH), was prepared. Attempts to prepare the target peptides using this new building block also failed as were attempts using an Asn(OH) building block with the hydroxamic acid side chain unprotected.
Driving Higher Education Sustainability: Investigating Practices, Cultural Influence and External Pressures in Nigerian Higher Education Institutions
(University of Waterloo, 2025-09-26) Jimoh, Ibrahim
While scholars have argued that Higher Education Institutions (HEIs) have the potential to help build a sustainable future, there remains a lack of understanding of what it means to strengthen sustainability practices and culture, especially in developing nations where multifaceted sustainability concerns exist. This dissertation uses the Sustainability Tracking and Rating System (STARS) framework to investigate campus sustainability practices and implementation barriers within the unique context of Nigerian HEIs, with a focus on understanding the influence of hierarchical organisation culture and external pressure – whether coercive, normative, and/or mimetic – on sustainability performance. Drawing on the Competing Value Framework (CVF) to identify institutional policies, leadership and management styles as the three major components of hierarchical culture, findings reveal the absence of a standard framework for measuring sustainability performance and the lack of distinct departments for sustainability teaching and research. While institutional policy and leadership style were found to promote sustainability initiatives, a rigid management approach affects adaptability and innovation, which are critical to sustainability project implementation. Additionally, external pressures were found to drive sustainability initiatives. This research advances the application and adaptation of sustainability theories within the Nigerian context, providing a novel framework for Africa and other developing countries, while offering practical recommendations for policy adjustment, institutional management techniques, and mechanisms for governments to promote sustainability performance in HEIs within the context of developing countries.
Towards the synthesis of coinage metal chalcogen compounds stabilized by a bidentate N-heterocyclic carbene
(University of Waterloo, 2025-09-26) Alex, Alice
Group 11 metal chalcogen clusters have been of interest due to their potential applications in light emitting materials. Although group 11 metal chalcogen complexes with phosphine ligands have been extensively examined and most of them reported do not contain N-heterocyclic carbene (NHC) ligand. This thesis examines how the rigid bidentate NHC, 1,1’-(dibenzyl)-3,3’-(1,2-xylylene)dibenzo[d]imidazol-2-ylidene) (bisNHCBn) can be incorporated into the gold(I) metal – chalcogenolate (chalcogenolate = RSe-; R = organic moiety) and gold(I) chalcogenide (chalcogenide = Se2-) complexes. In these studies, the chalcogen reagents Se(SiMe3)2 or RSeSiMe3 are reacted with the gold coordination complex [(AuOAc)2(bisNHCBn)] to target Au(I) selenide and Au(I) selenolate clusters with bisNHCBn. The preparation, characterization, and UV-vis absorption studies of the resulting clusters are presented.
Recognition and revitalization of ecocultural landscapes: Indigenous plant management throughout space and time
(University of Waterloo, 2025-09-25) Wickham, Sara
Indigenous Peoples of coastal British Columbia have co-evolved with the temperate rainforest ecosystems of the Pacific Northwest for millennia, cultivating ecocultural landscapes through sophisticated plant management practices grounded in relational worldviews. This thesis explores the historical and ongoing role of Indigenous plant stewardship in shaping biodiversity, ecosystem function, and cultural resilience. Drawing on ecological, archaeological, and ethnobotanical data—as well as community-engaged research with Indigenous Nations—this work highlights the diversity of management systems, from clam gardens to orchards of Pacific crabapple (Malus fusca). Recognizing the negative effects colonial disruptions have had on these systems, I examine how Indigenous-led restoration revitalizes both degraded landscapes and intergenerational knowledge systems and outline the potential for Indigenous-led restoration to influence broader conservation and social justice goals. Through an interdisciplinary, collaborative approach, this research contributes to the recognition, recovery, and renewal of ecocultural landscapes in an effort to support Indigenous sovereignty and self-determination through land stewardship.
Concert: Elementary VR Interactions Augmented By Bimanual Input
(University of Waterloo, 2025-09-25) Zhang, Futian
Many elementary tasks in Virtual Reality (VR)—such as pointing, locomotion, and command selection—are still predominantly performed through unimanual interaction, even though the non-dominant hand often remains available. When these tasks require multiple sequential steps, their frequent use can increase overall interaction time and user effort. By engaging both hands in complementary roles, some of these tasks can be streamlined into more efficient, parallelized actions without sacrificing intuitiveness. This thesis, Concert, investigates how bimanual input can optimize such underexplored opportunities through three novel interaction techniques. The first, Conductor, is an intersection-based 3D pointing method where the dominant hand controls an aiming ray while the non-dominant hand positions an intersecting plane to determine cursor depth. Compared to Raycursor, a state-of-the-art VR pointing technique, Conductor enables faster and more accurate target selection. The second project, Fly The Moon To Me (Locomoontion), extends Conductor to 3D object manipulation for locomotion, integrating vertical (height) and horizontal (planar) adjustments into a single fluid operation. Users generate a preview copy of a target object, reposition it precisely in 3D space, and then align the original object and surrounding environment to the preview. In a teleportation task, Locomoontion outperformed Point & Teleport and Point & Tug, reducing completion time and physical effort. The third project, Drum Menu, accelerates command selection through bimanual shortcuts inspired by marking menus. Users select commands by joystick rotation, stroke drawing, or directional pointing, with the bimanual variant granting simultaneous access to two menu levels. In user studies, bimanual configurations were faster than unimanual ones for a 4-item layout, with participants preferring the bimanual joystick menu; however, 8-item layouts increased error rates among experienced users. Collectively, these studies show that many common VR tasks can be made more efficient through carefully designed bimanual interaction, providing concrete design guidelines for integrating both hands into future immersive systems.

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