UWSpace

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Recent Submissions

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    Decentralized and Agentic Spectrum Management in Cognitive Wireless Networks
    (University of Waterloo, 2026-05-11) Abognah, Anas
    Dynamic spectrum management and sharing have been the subject of extensive research and development for many years. The ever-increasing demand for wireless spectrum from an exponentially growing number of devices and applications has led to a spectrum scarcity problem that remains unsolved. In addition, the rigid and prolonged nature of the regulatory processes of manually allocating spectrum has led to large swaths of spectrum bands being underutilized and inaccessible to new applications. Dynamic spectrum sharing can alleviate these problems by enabling new applications and devices to opportunistically access unused spectrum. Multiple spectrum sharing frameworks have been proposed by regulatory bodies where access to the shared spectrum is controlled and managed by a centralized third-party controller. However, these centralized spectrum sharing frameworks fail to provide truly dynamic and scalable spectrum sharing as they lack mechanisms for spectrum trading and do not provide incentives for primary users to participate in such models. In addition, existing decentralized spectrum management approaches rely on numerical optimization models that lack autonomous decision making capabilities, and are semantically blind and unable to interpret the unstructured regulatory policies and requirements. The need for a fully dynamic, and autonomous, spectrum sharing framework that satisfies the regulatory requirements and provides built-in economic incentives still exists. In this thesis, we propose and implement a fully decentralized spectrum management and sharing framework that resolves the issues inherent in the centralized model and closes the semantic gap through autonomous cognitive agents. We implement a comprehensive decentralized model that converges blockchain technology, federated learning, and Large Language Model (LLM) agents to automate and optimize dynamic spectrum sharing, sensing, and access in a single framework. The implemented model eliminates the reliance on centralized brokers through a two-tier Hyperledger Fabric blockchain network that guarantees trust, transparency, and immutable audit trails for spectrum sharing while eliminating single points of failure. In addition, the model facilitates cooperative decentralized spectrum sensing via federated model training on the blockchain achieving 92% detection accuracy. Finally, we implement BLAST (Blockchain LLM Agentic Spectrum Trading), which eliminates static decision-making and requirements analysis through autonomous cognitive agents. We demonstrate that LLM-driven agents employing game-theoretic reasoning within second-price sealed-bid auctions maximize social welfare and spectrum allocation efficiency and significantly outperform traditional heuristic strategies and state-of-the-art non-LLM decentralized models. This research establishes a concrete architectural blueprint for 6G and beyond, where decentralized intelligence, economic incentives, and regulatory compliance coexist within a unified, autonomous execution framework.
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    Putting Humpty-Dumpty back together: characterizing coherent recombination in Stern-Gerlach interferometers
    (University of Waterloo, 2026-05-11) Meng, Danny
    I show that superficially similar implementations of Stern-Gerlach Interferometers (SGIs) are expected to differ dramatically in their sensitivity to fields transverse to the primary acceleration direction. These transverse fields unavoidably accompany any static magnetic or electric field gradients, and have been shown by Comparat [Phys. Rev. A101, 023606 (2020)] to limit the precision application of SGIs. As a concrete example, I consider SGIs with ultracold Rb Rydberg atoms accelerated by spatially-varying electric fields and find that the deleterious effect of transverse fields imply that only some implementations (sequences of field gradients, internal state swaps and so-on) may exhibit fringes with high visibility. I further show that these differences are not strongly dependent on the form of the initial state. I provide a derivation of the Humpty-Dumpty equation for a general initial state and show that it holds for any interferometry sequence where the force as a function of time is piecewise constant. A modified version of the equation is shown to hold for any general sequence with a linear potential. I then extend this analysis to the transverse components of the described SGI, and give a form for the time evolution operator that is analogous to the one used in deriving the Humpty-Dumpty equation.
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    Controlling Metabolic Flux in Vacuum-Assisted Fermentation: The Interplay of pH and Operating Mode in the Valorization of Glucose to Volatile Fatty Acids and Biofuels
    (University of Waterloo, 2026-05-11) Hooshmand, Masoomeh
    Over the last two decades, anaerobic digestion has been increasingly implemented for organic waste treatment and production of biogas and electric energy which can be exploited beyond the plant boundaries. However, this process has limitations including high capital costs, low revenues from energy recovery, and the generation of nutrient-rich streams which require further treatment. Hence, anaerobic digestion was modified to go beyond energy recovery through the production and recovery of higher-value products via anaerobic fermentation. A newly proposed process called IntensiCarb™ (IC) applies vacuum-assisted fermentation to enable process intensification, enhance the resource recovery and implement circular economy policies. However, a critical knowledge gap exists regarding the influence of key operational parameters on its performance outcomes. This research addressed this uncertainty by systematically investigating the effects of pH (5.5, 7.0, and 9.0) and vacuum operating mode (sequential evaporation and intermittent evaporation) on the fermentation of glucose in lab-scale, semi-continuous reactors. The results demonstrated that pH regulated metabolic flux, inducing a shift from hydrogen- and butyrate-producing pathways to ethanol- and acetate-dominant fermentation as pH increased from 5.5 to 9.0. The vacuum-enhanced modes intensified the process, operating at double the organic loading rate of the conventional system. However, performance—evaluated based on COD-normalized product yields—was highly dependent on the interaction between pH and operating mode. At neutral and alkaline pH, a clear performance hierarchy was established against the baseline reference points: the intermittent evaporation-fermentation (IEF) mode yielded more total volatile fatty acids (TVFA) and hydrogen than both the sequential evaporation-fermentation (SEF) mode and conventional fermentation (CF). For instance, at pH 9.0, the IEF mode achieved a maximum TVFA yield of 63.0 ± 1.1%, outperforming both the SEF (60.1 ± 1.7%) and CF (56.7 ± 1.2%) baselines. This superior performance was attributed to the IEF mode’s ability to alleviate thermodynamic limitations (e.g., inhibitory hydrogen partial pressure) through more frequent, in-situ product removal compared to the end-of-cycle removal in SEF. Critically, this trend reversed under acidic conditions (pH 5.5), where CF produced a higher TVFA yield (64.6 ± 2.3%) than either IEF (53.2 ± 1.0%) or SEF (51.7 ± 1.0%). This antagonistic interaction was attributed to heightened product inhibition from the accumulation of undissociated VFAs under the intensified IC conditions. These findings reveal that while the IC process is a powerful platform for targeted chemical production, its performance is dictated by the interplay between pH and process intensification, which must be carefully managed to avoid inhibitory effects and maximize resource valorization.
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    Using GIS Spatial Analysis to Investigate Burial Complexities and Variation at Wadi Faynan 100, Jordan
    (University of Waterloo, 2026-05-11) Schwarz, Maegen-Rose
    This research investigates the spatial and stylistic relationships between EBA Ib burials that were excavated during the 2019 and 2023 field season of the Barqa Landscape Project (BLP), located in Wadi Faynan, Jordan. Spatial analyses included Near analysis, Hot spot analysis, and Inverse weight distributed (IDW) analyses which were conducted through the use of ArcPro. Results showed an increased level of grave good variety present in the burials located on the southern hills of WF100. Emerging grave pairs (Graves 1 & 2, 4 & 5, 6 & 7, 8 & 9, and 10 & 11) were found to hold reciprocated proximity ranking. There was no apparent sign of hot or cold spot presence. Comparing the structures to one another and to external EBA Ib burial grounds, stylistic similarities between graves include external stone wall lining, flat floor stones, built in alcoves in the Northern end, and grave openings to the North while the burials run North - South. Similarities between Wadi Faynan 100 and other EBA Ib sites in the Southern Levant include grave orientation, flat floor stones and artifacts. Results conclude that the Wadi Faynan 100 burial ground displays a level of connection between graves, while also affording room for stylistic difference. While sharing stylistic components of other EBA Ib burial grounds found within the southern Levant, WF100 maintains its own individuality in terms of construction and patterns.
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    Theory, Experience, and Instinct: How AAA Game Studio UX Leaders Navigate Pre-Production
    (Association for Computing Machinery, 2026-04-13) Randelshofer, Ivana; Tu, Joseph; Cao, Yifan; Mogavi, Reza Hadi; Mäkelä, Ville; Nacke, Lennart E.
    Academic frameworks have limited practical application in game pre-production because they do not map well to industry contexts and constraints. Through semi-structured interviews with 15 senior UX leaders from AAA game studios, we examined how practitioners make design decisions during early development. Our findings show a tripartite approach: (1) academically-grounded translation, where practitioners selectively adapt formal theories; (2) experience-based codification, where teams systematize tacit knowledge into reusable artifacts; and (3) intuitive gut feeling, where expertise guides decisions without formal frameworks. We introduce organizational structures (i.e., strike teams and competency teams) that shape how academic knowledge is translated in practice. Our work challenges the traditional view that practitioners should directly apply academic theory. Academia’s unique opportunity here is to provide the conceptual building blocks that enable solutions practitioners need. A change that begins with knowing how practitioners already translate academic knowledge into actionable practice.