UWSpace

UWSpace is the University of Waterloo’s institutional repository for the free, secure, and long-term home of research produced by faculty, students, and staff.

Depositing Theses/Dissertations or Research to UWSpace

Are you a Graduate Student depositing your thesis to UWSpace? See our Thesis Deposit Help and UWSpace Thesis FAQ pages to learn more.

Are you a Faculty or Staff member depositing research to UWSpace? See our Waterloo Research Deposit Help and Self-Archiving pages to learn more.

Photo by Waterloo staff

Communities in UWSpace

Select a community to browse its collections.

Recent Submissions

  • Thumbnail Image
    Item type: Item ,
    How to Color Graphs, and How Not to Chase Pointers
    (University of Waterloo, 2026-05-15) Mittal, Parth
    We present several results in the graph streaming and number-in-hand communication models. In the graph streaming model, the edges of the input graph stream by one-by-one, and the algorithm must process this stream with limited memory, which is significantly smaller than required to store the entire graph. Brooks' Theorem states that a graph with maximum degree Δ can be Δ-colored as long as it is not a clique or an odd-cycle. We show a 1-pass, O(n polylog(n)) space algorithm that can Δ-color a graph given as a stream. This is optimal up to log n factors. In the number-in-hand communication model, the input to some relation is partitioned between k players, who work together to compute an output to the relation while minimizing the number of bits they communicate to each other. We have three results in this model. First, we show an O(n) communication protocol that can (Δ + 1)-color a graph, whose edges are partitioned between two players. This is optimal up to constant factors. Our second and third results are about the pointer chasing problem. In the pointer chasing problem, two players receive functions from [n] → [n], and wish to find the sequence of elements of [n] obtained by applying their functions alternately k times on the starting element 1. We show that any k / 1000 round communication protocol that solves this task must use Ω(n) communication. This lower bound is optimal up to factors of log n. We also show an optimal lower bound for any (k - 1) round protocol that solves a version of this problem where each value of the input functions is further obscured behind a set intersection instance.
  • Thumbnail Image
    Item type: Item ,
    Evaluating the Conservation Regime for Boreal Caribou in Alberta and Ontario, Canada
    (University of Waterloo, 2026-05-15) Shin, Abby Leilah
    The protection and recovery of species at risk is critical for remediating Canada’s biodiversity crisis. This thesis examines Canada’s legal and policy-based conservation regime as it applies to boreal caribou in Alberta and Ontario. Listed as threatened for decades, boreal caribou continue to experience population declines and habitat degradation despite their significant cultural importance and well-resourced conservation frameworks. As these caribou reflect the overall health of Canada’s boreal landscapes, their precarious status raises broader questions about how federal and provincial conservation efforts perform within areas of natural resource development. This study uses a large-scale literature and policy analysis, a novel evaluation framework, and interviews with eNGO, academic, natural resource, and bureaucratic experts to answer the overarching question: Is Canada’s legislative, regulatory, and policy-based biodiversity conservation regime effectively protecting and recovering boreal caribou in Alberta and Ontario? Findings illustrate how boreal caribou lose out within a complex ecosystem of social, economic, and political priorities. While research and planning for boreal caribou in Alberta and Ontario is relatively robust, tangible outcomes are inhibited by flawed laws and policies which falter upon implementation. Conservation frameworks remain non-committal to habitat protection and disturbance thresholds, whilst being predicated upon uncertain habitat recovery. In Alberta, these challenges are exacerbated by highly subjective land use management, a reliance on intensive predator reduction programs, and severely fragmented caribou ranges. In Ontario, weakening protections are accelerating incoming declines and fragmentation across relatively intact distributions. Overall, this study diagnoses systemic barriers to effective boreal caribou conservation in the two provinces, identifies opportunities for further research, and contributes to the growing empirical evidence for necessary improvements to species at risk governance in Canada.
  • Thumbnail Image
    Item type: Item ,
    Forage Crop Productivity and Nutrient Use Efficiency on Newly Converted Boreal Podzolic Soils in Central Labrador
    (University of Waterloo, 2026-05-15) Dhindsa, Aman
    Climate change is driving agricultural expansion into Canada’s boreal north, however, the sandy acidic, and nutrient poor Podzolic soils resulting from forest-to-farmland conversion remain severely under studied for their capacity to support crop production. This study evaluated the effects of soil fertility enhancing treatments, including nutrient sources; inorganic mineral fertilizer, organic marine waste (e.g., shrimp compost, shrimp waste, and fish meal), forage biomass incorporation, and liming agents/organic matter inputs; limestone, peat moss, their combination, and biochar, on forage crops (e.g., oat, pea, and oat-pea intercrop). Yields, nutrient uptake, and nutrient use efficiency for N, P and K were evaluated across three boreal farmlands near Happy Valley-Goose Bay, Labrador, Canada. The three farmlands, Birch Lane (BL), Taiga Valley (TV), and Natures Best (NB), differed in conversion history, baseline soil fertility, and management, spanning a gradient from infertile, recently bulldozed mineral soil at TV to a moderately rehabilitated pasture under long‑term agricultural management at BL. Field experiments were conducted over two growing seasons (2023 and 2024) using randomized complete blocks with factorial design (factor 1: nutrient source, factor 2: liming agents/organic matter inputs). Results showed that forage crop yields and nutrient uptake for N, P, and K were influenced by both nutrient sources and liming agents/organic matter inputs applied (p<0.05), with the largest effects seen in the least fertile soils. While treatments were distinct but comparable across the three farms, forage responses were site specific, reflecting the overriding role of inherent soil fertility. In the longer-term managed BL field, inorganic and organic nutrient sources as well as application of limestone with peat, influenced yields, nutrient uptakes and nutrient use efficiencies (p<0.05). At BL, when shrimp compost was applied at similar N rates to the inorganic mineral fertilizer, shrimp compost produced higher yields. At the very recently converted TV, meaningful yields (above 1 t/ha) required the combined application of strong nutrient inputs with organic matter and acidity improving amendments (p<0.05). The application of hardwood biochar at TV, produced the highest yields and nutrient uptakes on the farm when paired with fish meal in the first year. At the intermediate fertility site NB, organic fertilizers, including shrimp compost and shrimp waste, performed similarly to inorganic mineral fertilizer, showing promise as locally useful organic marine waste by-products. Biomass incorporation contributed negligible available nutrients within a single season and did not improve yields above control. Nutrient use efficiency metrics revealed that high efficiencies were not solely a product of experimental soil inputs, but were likely influenced by inherent soil conditions, underscoring the importance of conversion history and cumulative land management on nutrient cycling in boreal agricultural soils. These findings provide evidence that northern boreal farms, such as those in Happy Valley-Goose Bay, can have agronomically meaningful forage crop production (5-7 t/ha) if soil fertility management is matched to site-specific constraints. The conversion history of these lands determines how intensive agricultural management must be to achieve crop productivity. As boreal agricultural development continues to expand in Newfoundland and Labrador and across northern Canada, this study highlights the importance of soil fertility management strategies that consider the interacting roles of nutrient supply, soil acidity, and organic matter status.
  • Thumbnail Image
    Item type: Item ,
    Development of Molecular-Pore-Containing Polymer Semiconductors via Thermal Side-Chain Cleavage for Enhanced Alcohol Vapor Sensing in Organic Thin-Film Transistors
    (University of Waterloo, 2026-05-15) Papazotos, Jimmy
    This work presents the development of a low detection-limit ethanol vapor sensor, operating as an organic thin-film transistor (OTFT). OTFTs have garnered much attention for their use in gas sensing applications; owing to their low-cost, relatively simple fabrication and ability to be deployed as miniaturized and wearable devices. As such, a series of polythiophenes were synthetized in this work with the aim of being the semiconductive channel material in ethanol vapor sensors. The materials were synthesized with various functionalized side chains – either thermally cleavable or stable in nature. The thermally cleavable sidechains (TCSs) are ester functionalities which can be removed and converted to carboxylic acids upon high temperature post-processing of the devices. The content of TCSs / thermally stable side chains within the polymers in the series were systematically altered to investigate their effect on sensing performance. It was found that complete side chain removal (owing to 100% use of TCSs) totally inhibits sensing performance due to collapse of the film morphology after post-processing. However, including thermally stable side chains in the polymer structure acts as a molecular scaffold and preserves film morphology after TCS removal. This imparts porosity into the thin-film, which facilitates analyte vapor diffusion into the sensing layer and consequently enhances the ethanol vapor sensitivity. A sensitivity increase of ~26% is observed after side chain removal in polymers containing molecular scaffolded structures, proving the formation of stable pores into the polymer films.
  • Thumbnail Image
    Item type: Item ,
    Anxiety disorder agreement among children with chronic physical illness and their parents
    (University of Waterloo, 2026-05-15) Parks, Reese
    Background: Assessment of child psychopathology using multiple informants provides a more comprehensive and accurate evaluation of child mental health; however, parent-child agreement is low-to-moderate in child psychiatry and tends to be lower for internalizing disorders. Children with chronic physical illness (CPI) are at an elevated risk of developing anxiety disorders, making accurate assessment especially important in this population. Despite this, longitudinal patterns and determinants of parent-child agreement in children with CPI remain underexplored. Objectives: The objectives of this thesis were to: (1) Estimate the magnitude of informant agreement for anxiety disorders on the Mini-International Neuropsychiatric Interview for Children and Adolescents (MINI-KID) between parents and children with CPI at baseline, 6, 12, 24, and 48 months, (2) Explore whether child sex moderates parent-child agreement, and (3) Identify sociodemographic and health factors associated with parent-child disagreement for anxiety disorders on the MINI-KID over time. Methods: Data for 119 dyads came from the Multimorbidity in Youth Across the Life-course (MY LIFE) study, a longitudinal study of children aged 2 to 16 years who had been diagnosed with a CPI and their primary caregiver. The prevalence-adjusted bias-adjusted kappa (PABAK) estimated the magnitude of agreement between parents and children with CPI at baseline, 6, 12, 24, and 48 months. Sex-stratified agreement analyses were conducted using the PABAK to investigate whether parent-child agreement was moderated by child sex. The method of variance estimates recovery (MOVER) was used to construct a confidence interval for the difference in κ estimates between male and female children at each timepoint. A generalized estimating equations model examined factors associated with parent-child disagreement over time. Results: Agreement ranged from fair to substantial over time (κ = 0.40-0.65). For male children, agreement was moderate to almost perfect (κ = 0.47-0.82), whereas for female children, fair to moderate agreement was observed (κ = 0.32-0.51). Moderation by child sex was only found at 6 and 48 months. Compared to baseline, time at 6 months (OR = 0.46, 95% CI = 0.23-0.91, p = 0.026) and 12 months (OR = 0.55, 95% CI = 0.31-0.97, p = 0.040) were associated with lower odds of disagreement. Female children were found to have significantly higher odds of disagreement compared to male children (OR = 2.04, 95% CI = 1.20-3.46, p = 0.008). Parents who were not partnered had lower odds of disagreement relative to partnered parents (OR = 0.27, 95% CI = 0.10-0.71, p = 0.008). Higher levels of parent psychopathology were also associated with increased odds of disagreement (OR = 1.15, 95% CI = 1.01-1.31, p = 0.032). Conclusion: Parent-child agreement ranged from low-to-substantial and varied over time. Moderation by child sex was only evident at 6 and 48 months. Predictors of parent-child disagreement may help identify dyads who may be at greater risk for informant discrepancies. Future research should examine the underlying mechanisms driving parent-child disagreement to inform targeted interventions that help strengthen agreement among parents and children with CPI.