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 ,
    Classification Results for Intersective Polynomials With No Integral Roots
    (University of Waterloo, 2025-12-08) Banks, Nicolas
    In this thesis, we algebraically classify strongly intersective polynomials - polynomials with no integer roots but with a root modulo every positive integer - of degree 5--10. In particular, we compute a list of possible Galois groups of such polynomials. We also prove constraints on the splitting behaviour of ramified primes (i.e. primes that ramify in a splitting field of the polynomial). In the process, we show that intersectivity can be thought of as a property of a Galois number field, together with its set of subfields of specified degrees. This was achieved with characterisations of Berend-Bilu and Sonn, the latter of which we also generalise. Implementations in SageMath and GAP are provided. We also utilise Hensel's Lemma and other standard results on the local behaviour of simple field extensions.
  • Thumbnail Image
    Item type: Item ,
    Hardware-Assisted Defenses for Data Integrity and Confidentiality
    (University of Waterloo, 2025-12-08) ElAtali, Hossam
    The increasing complexity of modern computing systems and their exposure to the internet expose sensitive data to a range of security threats from remote adversaries. Bugs in software can lead to run-time attacks that gain direct access to sensitive data in memory, compromising its integrity and confidentiality. Furthermore, hardware and/or compiler optimizations can introduce data-dependent behavior that expose sensitive data to side-channel leakage, even in the absence of software bugs, breaking confidentiality. As business needs evolve, different usage scenarios, such as outsourced computation, have gained popularity, making the task of protecting data integrity and confidentiality more complex. This dissertation investigates how the integrity and confidentiality of sensitive data at run-time can be efficiently preserved through hardware-assisted mechanisms. I consider a range of usage scenarios and threat models, from protecting data sent to remote servers for outsourced computation by untrusted code, to protecting data processed locally from other vulnerable or malicious parts of the system. Specifically, this dissertation addresses: 1. how to efficiently protect data confidentiality against side-channel leakage with negligible overheads. Existing solutions to side-channel leakage suffer from significant overheads, making their deployment difficult in situations where performance is critical. I address this problem with CacheSquash, a software-transparent hardware mechanism to effectively harden against transient side-channel attacks such as Spectre and Meltdown with near-zero overheads. 2. How to combine protections against both direct access and side channels. I propose BliMe, a novel architecture that relies on remote attestation, taint-tracking and hardware-enforced data obliviousness to protect sensitive data processed by untrusted code in an outsourced computation setting. 3. For integrity, I propose PBI, a novel hardware primitive that enables efficient memory protection for sandboxing and in-process isolation, thereby safeguarding both data confidentiality and integrity. 4. Finally, I address how to efficiently combine memory safety and side-channel protection mechanisms for data integrity and confidentiality. For this, I propose BLACKOUT, a hardware-software extension to CHERI that enforces data-oblivious computation on sensitive data, and inherits the memory safety properties of CHERI, all while introducing minimal overheads. The proposed solutions confirm that hardware-assisted mechanisms can indeed be used to efficiently protect data at run-time, both from direct access and side-channel leakage. I conclude my dissertation with promising directions for future work.
  • Thumbnail Image
    Item type: Item ,
    Evaluating Face Mask Efficiency on Children and Adults
    (University of Waterloo, 2025-12-05) El Khayri, Hicham
    Small infectious aerosols have been a major vector for the spread of diseases such as COVID-19 and influenza. During the recent global pandemic, masking played a key role in reducing airborne transmission, although significant variability has been noted in the ability of different mask types to limit pathogen-laden aerosol dispersion and inhalation. Moreover, there remain significant gaps in the literature regarding mask performance for children. The aim of this thesis is to characterize mask inward protection efficiency for both children and adults, and source control efficiency for children in the 0.2 μm to 1 μm particle size range. An approach based on the conservation of mass guided the experimental methodology used to estimate mask filtration characteristics. For all tested masks, the material filtration efficiency was measured to be at or near 100%, whereas fitted filtration efficiencies for both source control and personal protection were significantly lower. This disparity underscores the highly degrading effects of leakage from gaps at the mask-face interface. Inward protection efficiency of N95, KN95, and surgical masks donned regularly and using the tie and tuck method were estimated on a medium NIOSH adult head form. The tested N95 barrier provided the greatest protection, followed by the KN95 respirator, while the surgical masks offered the least protection. Use of the tie and tuck for surgical masks method yielded only a small, statistically insignificant improvement in inward protection compared to regularly worn variants. Incorporating results from broader literature, mean inward protection efficiency ranges of [67.9%,100%] and [12.5%,79.6%] were determined for the N95 and regularly worn surgical masks, respectively. Both inward protection and apparent filtration efficiencies of adult, modified adult, and child variants of the KN95, CA-N95, and surgical mask as well as the N95 respirator, were estimated on a child manikin. Results further underscore the critical importance of proper fit to mask performance. Child-sized respirators provided higher source control and personal protection compared to other barriers tested. In contrast, the adult-sized surgical mask, which exhibited a loose fit on the child manikin, demonstrated poor performance in both metrics due to the highly degrading effects of leakage. Overall, whenever both variants are available, adult-sized masks demonstrate markedly reduced fitted efficiencies on the child manikin relative to child-sized variants, attributed to larger gaps at the mask-face interface. Flow visualization of air exhaled through the tested barriers qualitatively corroborated these findings, revealing substantially reduced leakage for child-sized variants compared to adult-sized equivalents. Given the increased sensitivity of children to mask breathing resistance, pressure differentials measured across masks donned on the child head form provided relative indicators of breathability. Results demonstrated that masks with similar filtration efficiency can exhibit significant differences in breathability. For example, the child-sized CA-N95 achieved equal or greater fitted filtration efficiency while consistently maintaining lower pressure drops compared to the child KN95. In fact, KN95 respirators showed differential pressures greater than or equal to those of all other tested masks. For a given mask type, better fit was associated with higher differential pressures. However, across different mask designs, higher filtration efficiency did not necessarily compromise breathability.
  • Thumbnail Image
    Item type: Item ,
    FROM THE MOUTHS OF HUNTERS: HUNTER PERCEPTIONS IMPROVE UNDERSTANDING OF THE RELATIONSHIP BETWEEN HUNTERS AND CONSERVATION IN CANADA
    (University of Waterloo, 2025-12-05) Basdeo, Maya
    As a group of nature-based outdoor recreationists, hunters in Canada are not well understood, particularly in the context of their role in conservation. Hunters in Canada are not typically equated with being conservation actors, however there is a dearth of current academic literature that addresses the relationship between hunting and conservation in Canada and thus hunters may not accurately be represented within conservation circles. Collaboration between different groups of conservationists could be improved, and gaining a better understanding of how hunters perceive their place in conservation may contribute to greater unity around issues of conservation concern. The research question I explored was “Do hunters in Canada perceive they contribute to conservation, and if so, in what ways?”. I used an anonymous online questionnaire to survey hunters across Canada using Qualtrics as the survey tool. The survey link was distributed through six provincial and territorial hunting-conservation organizations affiliated with the Canadian Wildlife Federation: Ontario Federation of Anglers & Hunters, Manitoba Wildlife Federation, Saskatchewan Wildlife Federation, Alberta Wildlife Federation, B.C. Wildlife Federation, and Yukon Fish & Game Association. The survey consisted of 23 questions and was conducted over a six-week period in the fall of 2023. 4022 valid responses were received from every province and territory, with the majority from Ontario. Four key themes emerged from the survey results of hunters in Canada: hunters identified more strongly as conservationists than as hunters, hunters identified numerous ways in which they participate in and support conservation, hunters are political actors, and hunters can be allies for conservation. Focusing on hunter perceptions was a necessary first step in exploring the relationship between hunters and conservation in Canada. The breadth of these results highlight opportunities for further empirical research and the need for more research to be conducted in Canada on this topic.
  • Thumbnail Image
    Item type: Item ,
    Quantum Fields in Curved Spacetimes: From Detector Entanglement to Black Hole Thermodynamics
    (University of Waterloo, 2025-12-05) Bhattacharya, Dyuman
    This thesis presents two independent investigations into quantum field theory in curved spacetime. The first concerns relativistic quantum information, with a focus on entanglement harvesting and detector-based probes of quantum fields in curved spacetimes. The second addresses semiclassical aspects of black hole thermodynamics in AdS braneworld settings, incorporating the backreaction of quantum fields to all orders of perturbation theory, and extending previous studies of quantum black holes to include both charge and spin. In Part I, we study the entanglement of quantum fields in curved spacetime, using localized particle detectors interacting with a scalar field. We analyze scenarios involving both flat and curved backgrounds, including gravitational shock waves, the BTZ black hole, and general dimensional anti–de Sitter and de Sitter spacetimes. For the case of initially entangled detectors, we find that interactions with the field can lead to either degradation or amplification of entanglement, depending on the initial state and spacetime geometry. We further derive exact expressions for density matrix elements, at the lowest perturbative order, in the form of infinite analytical series, for detectors on static worldlines in various spacetimes. The transition rate of an in-falling detector in the BTZ black hole spacetime is also derived as an infinite series. These analytic results allow for exact evaluation of quantities, namely the entanglement measures of concurrence and negativity, which are typically computed numerically. In addition, we provide a new example of the ability of detectors to distinguish topologically distinct spacetimes which are locally identical outside of horizons, focusing on the ℝP² and Swedish geons built from the BTZ spacetime. Our results show that localized measurements are sensitive not only to curvature but also to topological features of the underlying geometry. Part II is concerned with the construction and thermodynamic analysis of quantum-corrected black holes in a doubly holographic braneworld model. We obtain a charged and rotating solution localized on an AdS₃ brane embedded in an AdS₄ bulk, incorporating the full backreaction from conformal fields to all orders of perturbation theory. We compute the thermodynamic properties of these black holes, and examine their behavior in extended thermodynamic phase space where the cosmological constant is a variable. We find that the inclusion of charge or spin removes re-entrant phase transitions present in the neutral-static case, and that the critical exponents of these objects match those predicted by classical mean-field theory. The re-entrant phase transitions of the neutral-static quantum black hole has critical exponents which differ from the mean-field values