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Recent Submissions

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    The Effect of Turfgrass-to-Meadow Restoration on Carbon Storage and Sequestration in an Urban Environment
    (University of Waterloo, 2026-07-02) Epp, Hayden
    Since 2013, Toronto and Region Conservation Authority has been restoring a 16 km hydro corridor in Scarborough, Ontario, actively removing turfgrass and replacing it with meadow. The primary intention of this project, known as The Meadoway, is to improve biodiversity and habitat connectivity in the city, but there is the potential for other co-benefits such as enhanced carbon storage and sequestration. We made use of the section-by-section restoration timeline in a space-for-time substitution to evaluate changes with time since restoration in three categories: unrestored turfgrass, recently restored meadow (restored in 2020-2024), and older restored meadow (restored in 2013-2016). First, we measured CO2 and CH4 fluxes biweekly to make estimates of daily net ecosystem exchange, gross primary production, and ecosystem respiration. We found that, cumulatively, both recent (−12.5 ± 19.1 mol m⁻² season⁻¹) and old meadow (−12.3 ± 6.44 mol m⁻² season⁻¹) acted as carbon sinks while unrestored turfgrass (+14.1 ± 17.0 mol m⁻² season⁻¹) acted as a net carbon source over the course of our sampling season. Next, we conducted a 366-day plant litter transplant experiment to investigate whether decomposition rates differ due to litter quality, site conditions, or a combination of both. We found that meadow litter decomposes 33.6% more slowly than turfgrass litter regardless of site, but all litter decomposed 34.7% more at recent meadow sites compared to turfgrass sites. We measured biomass production over the growing season by clipping aboveground biomass and using a modified soil ingrowth core method belowground. We found 272% greater aboveground biomass standing stock, and 213% higher belowground plant production in old meadow compared to turfgrass in 2025. Finally, we measured belowground carbon stocks, using a loss-on-ignition method to measure soil organic matter, soil carbonate content, and root organic matter. We found largely similar belowground carbon stocks in restored meadow as in turfgrass, with the important exception that the old meadow category had 22.4% lower surface soil organic matter compared to turfgrass. We lack baseline data on pre-restoration soil organic matter and suspect this is attributable to antecedent differences between the sections. In total, we provide convincing evidence that urban turfgrass-to-meadow restoration provides valuable climate mitigation co-benefits and could be considered a nature-based solution to climate change.
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    Assessment of Seat Belt Anchor Position on Rear Seat Occupant Kinematics in Frontal Impact Using a Validated THOR-5F Finite Element Model
    (University of Waterloo, 2026-07-02) Thangarajah, Patrick
    Rear seat occupant safety has been identified as an area of concern in frontal impacts, with small stature females experiencing severe injuries more frequently, including a higher rate of thoracic injuries. Seat belts, the primary restraint for rear seat occupants, have been identified as contributors to thoracic injury, with studies finding that belt geometry and belt anchor locations influence occupant response. A new small stature female Anthropometric Testing Device (ATD) to be used in vehicle testing is the THOR-5F ATD, designed with improved anthropometry and updated measurement capabilities, including four chest deflection sensors. In this study, a Finite Element (FE) model of the THOR-5F was validated against physical testing of the THOR-5F ATD in a Rigid Bench test configuration with a 23 g frontal crash pulse, by comparing belt interaction, iliac forces, pelvis accelerations, chest deflections, and head accelerations. The THOR-5F FE model was also assessed on a simplified version of an existing bench with a pivoting seat (Semi-Rigid Bench) and a 4-Point 2-Belt system, and the results were compared with those from a 9 g sled test reported in the literature. In both bench configurations, the overall THOR-5F FE response matched the reported physical response well, with an average ISO 18571 rating of 0.71, corresponding to a “Fair” grade. Physical testing of the THOR-5F ATD also showed bottoming out of the lower-right chest deflection sensor, which is currently under investigation as the THOR-5F design is being refined. Parametric studies were conducted to explore the effects of shoulder and lap belt anchor positioning in the fore/aft (X), lateral (Y), and vertical (Z) directions on THOR-5F FE peak chest deflections and peak resultant pelvis accelerations. The shoulder belt anchor X and Y-positions had a large effect on the overall peak chest deflection in both bench configurations, with rearward and inboard anchor locations reducing deflection, and the lowest deflections approximately 16% lower than the average. The lap belt anchor position had a smaller effect than the shoulder belt anchor on chest deflections. Based on preliminary chest deflection injury risk curves, rearward and inboard shoulder belt anchor positions resulted in lower corresponding AIS 3+ injury risks. However, the risks remained very high across all anchor configurations in both benches, indicating a need to implement restraint technologies, such as load limiters, in addition to favorable anchor positions. The lap belt anchor position had a larger effect on peak pelvis acceleration than the shoulder belt anchor position. The X, Y, and Z-positions of the lap belt anchor influenced the peak resultant pelvis acceleration in the Rigid Bench, with rearward, upward, and inboard locations reducing pelvis accelerations. The Y-position of the lap belt anchors and the YZ interaction had the largest effect on pelvis acceleration, indicating a complex interaction between the anchors and the Semi-Rigid Bench components. This study demonstrated that the Rigid and Semi-Rigid Bench FE models could replicate physical occupant and restraint responses, and that anchor position affected the chest deflection and pelvis acceleration of the THOR-5F FE. Future research should focus on belt material properties, vehicle fleet-specific anchor positions, the implementation of load limiters, and the combined interactions between shoulder and lap belt anchor positions.
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    Efficient High-precision Monitoring of Network Slices for 5G and Beyond Networks
    (University of Waterloo, 2026-07-02) Saha, Niloy
    Next-generation mobile networks are undergoing a fundamental transformation to support a variety of services such as Augmented Reality (AR), vehicular automation, and smart cities, each with very distinct performance requirements. The primary enabler for this transformation is network slicing, which enables partitioning of the shared physical infrastructure into isolated logical networks, each tailored to the performance requirements of its target service through slice-specific Service Level Agreement (SLA) guarantees. Realizing such network slices in practice depends critically on automated closed-loop management and orchestration mechanisms, where monitoring data drives analytical and control decisions. However, monitoring is a key bottleneck in achieving this goal: control logic can only optimize what it can observe, and observation is constrained by strict overhead, latency, and deployability limits. Existing monitoring solutions are domain-centric, statically configured, and not sufficiently expressive to capture the transient, end-to-end (e2e) performance signals that slice SLA assurance demands. The overarching goal of this dissertation is to build the foundation for efficient, high-precision monitoring for network slices in 5G and beyond networks. Towards achieving this goal, we address three distinct but coupled challenges across the monitoring stack. First, we introduce Monarch, a cloud-native architecture that abstracts slices as first-class monitored entities and enables direct computation of e2e slice Key Performance Indicators (KPIs) across heterogeneous domains. Next, we present SliceScope, a principled framework for dynamically allocating limited monitoring budget across slices with heterogeneous SLAs. Finally, we develop Kestrel, a detectability-driven, sketch-based telemetry mechanism for detecting and attributing transient Quality of Service (QoS) anomalies in shared user-plane resources without per-packet overhead. Together, these contributions demonstrate that efficiency and precision in slice monitoring are jointly achievable through cross-layer design spanning architectural abstractions, control plane intelligence, and data plane telemetry.
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    Effect of Modifying Visual and Sensory Feedback on Neural Error Processing During Sensorimotor Tasks
    (University of Waterloo, 2026-07-02) Du, Rachel
    The error-related negativity (ERN) is a frontocentral EEG component reflecting neural error monitoring during motor tasks, and has been identified as a promising input signal for brain-computer interface (BCI) systems. Although the ERN has been reliably observed across a range of motor and cognitive tasks, significant gaps remain in characterizing how sensory signals contribute to its generation and modulation. This thesis investigates how the central nervous system (CNS) integrates visual and proprioceptive feedback during motor error monitoring, as reflected in the ERN, across three experiments in which participants performed upper limb reaching tasks while EEG was recorded. The first experiment examined how the availability and fidelity of visual feedback influenced the ERN during a reaching task performed in a velocity-dependent curl force field. Three visual feedback conditions were applied in alternating blocks: a veridical cursor, a hidden cursor in which visual feedback was removed during the reach, and a cursor cloud that replaced the true cursor with a diffuse cluster of cursors to obscure its precise location. Trials were binned by three kinematic error metrics — integral error at 100 ms, signed maximum perpendicular deviation, and absolute maximum perpendicular deviation — and ERPs were generated for each bin. An ERN was elicited across all visual feedback conditions when trials were binned by integral error at 100 ms, and no significant difference in ERN amplitude was found between conditions. This result suggests that the ERN during reaching is driven primarily by early proprioceptive feedback rather than online visual feedback, consistent with the theory that the ERN arises from an internal error prediction mechanism using the efferent copy of the motor command. Binning by integral error at 100 ms was also found to be a more reliable method for eliciting consistent ERNs compared to maximum perpendicular deviation, highlighting the importance of selecting kinematic metrics that are temporally aligned with the ERN effect window. Additionally, ERNs were found to be elicited by trajectory deviations in both directions relative to the force field, with no significant difference in amplitude between error directions. The second experiment investigated how perturbing proprioceptive feedback through tendon vibration affected the ERN during a reaching task. Vibration was applied to the biceps brachii tendon at 90 Hz to induce an illusory perception of elbow extension, and participants performed reaches under conditions of full visual feedback, hidden cursor with no task feedback, and a transitional condition in which the vibration state was switched during hidden cursor trials. Kinematic results confirmed that the vibration successfully induced a proprioceptive shift: endpoint reach displacement differed significantly between vibration conditions when visual feedback was removed, with participants overextending when vibration was turned off following adapted reaches under vibration. When visual feedback was available, participants corrected for the proprioceptive shift, consistent with visual dominance over proprioception in multisensory integration. An ERN was elicited only when participants performed reaches with full visual feedback and without applied vibration. The absence of the ERN under vibration, despite comparable task performance, suggests that the ERN depends on the integrity of the proprioceptive re-afferent signal rather than task outcome, providing causal evidence that reliable proprioceptive feedback is a necessary condition for the error prediction process underlying the ERN. The third experiment examined how introducing a shift to the visuomotor mapping affected the ERN during reaching, using pilot data collected from five participants. A 2 cm spatial shift was introduced gradually to the on-screen cursor position along the direction of reach, creating a mismatch between the perceived and true end-effector positions that fell below the threshold of conscious detection. Participants adapted rapidly following each mapping swap, with endpoint reach displacement returning to within target bounds within the first few trials of each new mapping. Preliminary inspection of ERN amplitudes suggested that a negative deflection consistent with an ERN was present across all cursor feedback and visual shift conditions, with the largest mean amplitude observed in the first trials following a mapping swap to the shifted cursor condition. This is consistent with the finding from the second experiment that the ERN is preserved when proprioceptive feedback remains intact, and further suggests that the error prediction mechanism is sensitive to the introduction of a novel visuomotor mismatch. These trends also confirm that the absence of the ERN under tendon vibration in the second experiment was a consequence of the corrupted proprioceptive signal rather than the visuomotor mismatch it produced. Full statistical analysis awaits data collection from a sufficient number of participants. Taken together, the findings of this thesis support a model in which the ERN during reaching is generated through an internal predictive mechanism that depends on reliable proprioceptive re-afferent feedback, and in which visual feedback plays a reinforcing rather than primary role. These results advance our understanding of how the CNS integrates multisensory feedback for motor error monitoring, with implications for the development of more robust ERN-based BCI systems.
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    Adaptive Reuse of Federal Office Buildings into Housing: Leveraging Federal Office Downsizing Initiatives
    (University of Waterloo, 2026-07-02) Lai, Julian Jeun Yin
    As part of the August 2024 budget announcement, Canada’s federal government outlined a plan to optimize their real estate holdings by downsizing its office portfolio by 50%. In Ottawa, home to 42.2% of the federal workforce, this move would release 8.8 million sqft. The downtown core would be hit the hardest as widespread vacancies would force local businesses to close. This would harm not only the vitality of the area, but also the overall health and vibrancy of the city. This projected oversupply of office buildings lies in contrast to the Canada’s ongoing housing crisis. The country is desperately in need of affordable purpose-built rental housing. If it was to set a needs-based target for affordable rental housing it is estimated that the country would need 2 million affordable rental housing units at and below a minimum-wage income, which would take 30 years to build. Despite the federal government’s repeated commitments to addressing the issue, it has failed to dismantle the systemic profit-driven structures perpetuating residential alienation. This thesis builds upon existing research suggesting that converting federal offices into housing can address the housing crisis and repurpose soon-to-be vacant federal properties. It critiques current housing and adaptive reuse practices which are driven by profit and approach the crisis as a supply issue which perpetuates profit-driven commodification of housing which fails to disalienate housing. Ottawa presents opportunity to challenge the status quo of for-profit housing through federal-office-to-residential conversions. It imagines utilizing existing public assets - federal public land and vacant federal offices - for the public’s benefit by converting vacant federal offices in Ottawa into non-market housing. This can simultaneously lower the environmental impact of construction and construction costs while also creating decommodified, affordable, and good quality housing. Aside from revitalizing vacant buildings and building nonmarket housing, this strategy also has the added benefit of being environmentally beneficial too. Repurposing existing surplus buildings presents significant opportunity to mitigate building emissions through limiting construction and improving building performance which lowers operational energy-use and emissions. Research is grounded in axiological thought and seeks to critically examine, challenge, and redefine the underlying capitalist values embedded within Canada’s housing to support an expanded spectrum of what housing, living, and domesticity should and could be. Research methodologies consist of literature review, case studies, and speculative design as research. A literature review will act as the thesis’ theoretical framework by examining critical housing research challenging existing capitalist understandings of housing and propose nonmarket housing as the solution. Building on this will be a series of case studies, literature review, and speculative design to develop a successful and implementable nonmarket housing strategy. Case studies will examine successful nonmarket housing programs locally and internationally and measure both their successes and ease of implementation to outline an Ottawa-specific nonmarket housing strategy. This will be followed by a literature review and further case studies examining adaptive reuse strategies and office-to-residential conversions architectural, technical, and financial considerations to inform proper adaptive reuse practices. Finally, all research findings will be synthesized into a speculative design proposal for the conversion of the L’Esplanade Laurier federal office building in downtown Ottawa. The goal of the design proposal is to illustrate the viability and potential for impact of non-profit federal office-to-residential conversions. This thesis is intended to function both as a document demonstrating the potential for change within Canada’s current housing system and as a guide to federal office-to-residential conversions. It will demonstrate what is possible if all levels of government, housing developers, stakeholders, and community groups commit to systemic changes for housing disalienation. Housing within Canada can get better. Federal office-to-residential conversions can be part of the solution to the Canada’s housing system if the right steps are taken.