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.
Communities in UWSpace
Select a community to browse its collections.
- The University of Waterloo institution-wide UWSpace community.
Recent Submissions
Toward transactive control of coupled electric power and district heating networks
(Elsevier, 2022-12-19) Maurer, Jona; Tschuch, Nicolai; Krebs, Stefan; Bhattacharya, Kankar; Cañizares, Claudio; Hohmann, Sören
Although electric power networks and district heating networks are physically coupled, they are not operated in a coordinated manner. With increasing penetration of renewable energy sources, a coordinated market-based operation of the two networks can yield significant advantages, as reduced need for grid reinforcements, by optimizing the power flows in the coupled systems. Transactive control has been developed as a promising approach based on market and control mechanisms to coordinate supply and demand in energy systems, which when applied to power systems is being referred to as transactive energy. However, this approach has not been fully investigated in the context of market-based operation of coupled electric power and district heating networks. Therefore, this paper proposes a transactive control approach to coordinate flexible producers and consumers while taking into account the operational aspects of both networks, for the benefit of all participants and considering their privacy. A nonlinear model predictive control approach is applied in this work to maximize the social welfare of both networks, taking into account system operational limits, while reducing losses and considering system dynamics and forecasted power supply and demand of inflexible producers and consumers. A subtle approximation of the operational optimization problem is used to enable the practical application of the proposed approach in real time. The presented technique is implemented, tested, and demonstrated in a realistic test system, illustrating its benefits.
Developing an Agent-Based Model (ABM) to Explore the Geographic Redistribution of Snowmobilers During a Record Warm Winter
(University of Waterloo, 2025-06-20) Rubiano, Mave
Canada's snowmobile industry is the second largest market in the world, with Ontario generating over $3 billion in economic activity and supporting over 10,000 full time jobs. Inter-annual climate variability and record warm winters have underscored the vulnerability of the industry, which is predicated on natural snowfall and low temperatures to support over 100,000 riders across the 33,000 kilometers network of trails. However, critical regional and methodological gaps limit our understanding of the vulnerability of snowmobiling to both current conditions and projected climate change, with no available research that empirically explores the dynamic relationship between supply- and demand-side responses to marginal climatic conditions. The presented research develops an agent-based model (ABM) to simulate how trail availability influences the spatial redistribution of snowmobilers across Ontario. Using the record warm 2023/2024 winter season as a climate analogue, the ABM was informed by a geospatial analysis of trail network availability (i.e., supply-side vulnerability) and the results from an online survey of snowmobilers' (n=161) (i.e., demand-side vulnerability). Results from the geospatial analysis revealed significant trail closures across the province, with 14 districts having ≤5% trail availability in December followed by an early end to the season (≤1% of trails available in March). Survey findings revealed that 90.4% reducing riding frequency in response to trail closures, but strong willingness to travel (e.g., 61.5% travelled to alternative trails outside their preferred district due to closures, averaging 239.8km for day trips and 861.1km for overnight trips). The ABM simulated the movement of 1,000 snowmobiler agents across the 16 districts, resulting in significant redistribution patterns that underscore differential climate risks, such that some districts gained market share (e.g., Districts 1 and 3) while others incurred substantial losses (e.g., Districts 11 and 6). Collectively, the results suggest the future of snowmobiling in Ontario may involve substantial geographical shifts rather than outright market collapse, with important implications for tourism planning and rural economic development in a warming world.
Simulated spin qubits in silicon quantum dots and enhancement of InGaAs photodetectors
(University of Waterloo, 2025-06-20) Merino, Zach
Semiconductor quantum dot spin qubits are a leading candidate for scalable, fault-
tolerant quantum computing. Their advantages include nanoscopic device size, compat-
ibility with foundry fabrication processes, and long coherence times relative to gate du-
rations. The fabrication and control of a quantum processing unit composed of tens of
thousands to millions of physical qubits pose many engineering challenges. These chal-
lenges fall broadly into two categories: device design, such as optimizing the geometry for
high-quality qubit formation, and qubit control, which involves the precise manipulation
of spin or charge states in qubits that are capacitively coupled to numerous neighboring
electrodes. In this thesis, we develop a simulation tool that accelerates device design iter-
ation prior to fabrication by providing a priori knowledge of the quantum dot electrostatic
potential landscape as a function of external electrode voltages. This enables effective
spin and Hubbard Hamiltonian parameters to be computed before experimental charac-
terization, facilitating early-stage control method development and device performance
prediction. The tool, implemented as the Python-based QuDiPy package, integrates three-
dimensional finite-element Poisson solutions with modules for electrostatic reconstruction,
Hamiltonian parameter extraction, and control pulse optimization. Unlike previous dis-
jointed toolchains, QuDiPy offers a unified workflow for full-stack qubit control simulations,
including automated voltage-to-Hamiltonian mapping for exploring high-dimensional gate
voltage spaces and mitigating crosstalk in dense qubit arrays. The simulator is designed
to be memory- and CPU-efficient to enable computationally efficient simulation of linear
quantum dot arrays consisting of several qubits. Simulation of small quantum dot arrays
serves as a design tool for control protocols within multi-node quantum processors. Sim-
ulation of spin qubit dynamics in many-qubit nodes connected in a network enables the
study of required voltage ranges for maintaining stable charge configurations in the device.
It also supports the design of experimental input pulses to generate maximally entangled
Greenberger–Horne–Zeilinger (GHZ) states between nodes, a key step for implementing
surface code error correction protocols.
Spin qubit control requires a precise understanding of the impact of experimental con-
trols, such as electrode voltages or radio-frequency magnetic field amplitude and phase,
on effective parameters such as electronic g-factor, exchange energy, chemical potential,
etc. A mapping between experimental and effective parameters is created by performing
effective parameter calculations on two-dimensional cross-sections of the electrostatic po-
tential landscape obtained from a 3-dimensional Poisson solver nextnano++, a commercially
available, 3D Poisson solver chosen for its robustness, flexibility in defining quantum device
geometries, and proven accuracy in modeling semiconductor heterostructures at cryogenic
temperatures. First, a 2D cross-section of the electrostatic potential landscape is taken
along the growth direction of the quantum dot device, near the heterojunction where qubit
formation occurs. This region is selected because it captures the horizontal confinement
profile most relevant to charge localization and wavefunction shape. The cross-section is
extracted for all simulated voltage configurations applied to the gate electrodes. Second,
the single-particle ground state or first excited state wavefunctions are determined using
a non-uniform grid Schrödinger solver for all voltage configurations and for each isolated
quantum dot or nearest-neighbor quantum dot pair. The non-uniform grid provides higher
spatial resolution near confinement potential minima, enabling more accurate modeling
of localized wavefunctions where precision is most critical. The mapping between input
voltage and single-particle wavefunctions is leveraged, along with numerical integration
routines, to calculate the desired effective parameters as a function of voltage. The chemi-
cal potential, tunnel coupling, and onsite and interdot Coulomb parameters are computed
for each voltage configuration. This enables exact diagonalization of the Hubbard Hamil-
tonian at every point in voltage space and identifies the regions of charge stability for a
multiqubit quantum dot device. This step is essential for establishing control over the
quantum processor.
The second part of this thesis investigates optoelectronic device enhancement using
localized surface plasmons in nanocrystals. Fast and accurate detection of light in the
near-infrared (NIR) spectral range plays a crucial role in alleviating speed and capacity
bottlenecks in optical communications and in enhancing the control and safety of au-
tonomous vehicles through NIR imaging systems. Several technological platforms are cur-
rently under investigation to improve NIR photodetection, aiming to surpass the perfor-
mance of established III–V semiconductor p-i-n (PIN) junction technology. These plat-
forms include in situ-grown inorganic nanocrystals (NCs) and nanowire arrays, as well as
hybrid organic–inorganic materials such as graphene-perovskite heterostructures. How-
ever, challenges remain in NC and nanowire growth, large-area fabrication of high-quality
2D materials, and the fabrication of devices for practical applications. Here, we ex-
plore the potential for tailored semiconductor NCs to enhance the responsivity of planar
metal–semiconductor–metal (MSM) photodetectors. MSM technology offers ease of fabri-
cation and fast response times compared to PIN detectors. We observe enhancement of the
optical-to-electric conversion efficiency by up to a factor of ∼2.5 through the application
of plasmonically-active semiconductor nanorods and NCs. We present a protocol for syn-
thesizing and rapidly testing the performance of non-stoichiometric tungsten oxide (WO)
nanorods and cesium-doped tungsten oxide (CsyWO) hexagonal nanoprisms prepared in
colloidal suspensions and drop-cast onto photodetector surfaces. The results demonstrate
the potential for a cost-effective and scalable method exploiting tailored NCs to improve the performance of NIR optoelectronic devices.
The development of the sunk cost bias
(University of Waterloo, 2025-06-20) Sehl, Claudia G.
The sunk cost bias is when people overvalue objects or projects because they have already invested time, money, or effort into them. Most sunk cost research over the past 50 years investigated the bias in adults, exploring the conditions in which people expect themselves and others to be biased by sunk costs. However, very little work has examined the developmental origins of the bias, despite much evidence that young children reason about costs for a host of predictions and inferences about others. Across three papers, this dissertation examines children’s (N = 990) and adults’ (N = 934) sunk cost predictions. Chapter Two first explored whether children predict others’ actions are biased by sunk costs. After seeing agents collect two identical objects but being able to keep only one, adults expected agents will be biased by sunk costs and choose high-cost objects. However, 5- to 6-year-olds chose between high- and low-cost objects equally. Across four experiments, children consistently failed to anticipate that sunk costs biased others’ choices, their own hypothetical choices, or their choices in interpersonal contexts where costs are sunk by others. Children were not insensitive to costs, though, as children predicted agents would collect low-cost objects in the future. Together, the findings from this chapter show that children do not anticipate sunk cost bias across various scenarios. Chapter 3 tested between two accounts for why children overlook sunk costs when predicting actions. On one account, children do not see sunk costs as causing future outcomes, while on another, they can recognize this causal link but do not see actions as avoiding losses. In three experiments, 5-7-year-olds again did not expect sunk costs to bias others’ actions, as they responded at chance when predicting which objects agents would keep. However, children reasoned about sunk costs to predict emotion, anticipating that agents would feel sadder about high-cost objects. Together, the findings of this chapter support the view that children see sunk costs as causally relevant but do not expect actions to compensate for losses. Chapter Four examined whether children can be prompted to anticipate the sunk cost bias. Before predicting which objects agents would keep, children were asked about effort, waste, or negative emotion. In three experiments, children around age 6 predicted the sunk cost bias when prompted with effort and around age 7 when prompted with waste. Prompting children with waste did not always lead to sunk cost predictions, though, and children only showed some sensitivity to predicting the bias with negative emotion. Overall, this dissertation shows that children do not spontaneously predict the sunk cost bias. Yet, children are not entirely unable to reason about sunk costs, as they can recognize how sunk costs relate to waste, effort, and negative emotion, and predict the bias when prompted. This work deepens our understanding of children’s cost-based reasoning and the developmental trajectory of the sunk cost bias. This work also contributes to theories of the bias and raises questions about the role of experience and theory of mind in the emergence of sunk cost predictions.
Protecting Environmental and Cultural Water Through Collaborative Goverrnance and Impact Assessment: International, Canadian, and Saskatchewan Examples
(University of Waterloo, 2025-06-20) Bergbusch, Nathanael
Human activities and climate change threaten freshwater resources and Indigenous rights. Developments (e.g., irrigation, dams, mines) cumulatively pollute and alter the hydrology of fresh water, affecting ecosystems (environmental flow/water) and Treaty and Inherent Rights (cultural flow/water). However, development assessment and management may not guarantee the protection or connectivity of water downstream. Regional sustainability-based guidance is needed through collaboration between Crown and Indigenous governments. Through interviews, workshops, ecohydrology, and policy analysis, this dissertation investigates strategies for collaborative governance and impact assessment to protect water for the environment, human uses, and Indigenous rights at three scales: globally, nationally (Canada), and regionally (Saskatchewan’s Treaty Four). Treaty Four studies were co-created with File Hills Qu’Appelle Tribal Council’s Lands, Resources, Environment, and Stewardship Department (Ch. 2) and informed the design of global and Canadian studies. I systematically reviewed international English-language papers on the collaborative governance of environmental and cultural water to inform practice in Canada (Ch. 3). In Chapter 4, I investigated the uptake of environmental and cultural flows in Canadian legislation and assessment and suggested steps for their protection. Moving to Treaty Four, I examined barriers to water regulation (Ch. 5), developed flow-based sustainability criteria for the Qu’Appelle and South Saskatchewan sub-basins (Ch. 6), tested these criteria (Ch. 7), and proposed regional response options (Ch. 8) for the Lake Diefenbaker Irrigation Expansion and Agricultural Water Stewardship Policy (that promotes continued wetland drainage).
Overall, dissertation findings established that, worldwide, communities need to have a greater role in environmental and cultural water policy, planning, and impact assessment (Ch. 3). In Canada, experts detailed a need for water councils to set needs-based rules for environmental and cultural flows maintenance ahead of development (Ch. 4). In Saskatchewan, water protection is challenged because of abstraction and drainage not triggering assessments, impact and project splitting, a lack of regulation, weak effort to meet the duty to consult, and the absence of regional approaches for identifying and managing cumulative effects of abstraction and drainage initiatives (Ch. 5). Collaborative regional governance (Ch. 8) was identified as needed to support progress towards sustainability through restoration of water and land, equity, respect for Treaties, transparency, climate uncertainty, and procedural justice (Ch. 6, Ch. 7). Together, these studies demonstrate the opportunity for more collaborative regional governance and impact assessment of environmental and cultural water in Canada and inform recommendations for future management and study, provided in Chapter 9.