title: What? I Don’t Get What You Mean: Understanding Language in Childhood Epilepsy

contributor:
Im-Bolter, Nancie
Fitneva, Stanka
Psychology

subject:
language
self-other differentiation
theory of mind
childhood epilepsy

abstract: Research suggests that children with epilepsy may have impaired language and social competence. Little is known about their language profile or whether language is associated with social cognition in this population. The main goal of this dissertation is to understand language and its association with social cognition in pediatric epilepsy. Chapter 2 provides an overview of etiology and seizure classification and how clinical variations (e.g., diagnostic variables) contribute to the heterogeneous nature of pediatric epilepsy.  The systematic review of 83 studies in chapter 3 indicates a failure to distinguish developmental periods (e.g., middle-childhood vs. adolescence) when assessing language in pediatric epilepsy, little consideration for specific etiology (e.g., symptomatic) and seizure type (e.g., generalized seizures), and minimal assessment of morphology and phonology.  The meta-analysis of 13 studies in chapter 4 shows that children with epilepsy are at increased risk for language impairments and highlights a need for research focusing on semantic or syntactic language in children with generalized seizures.  Chapters 5 and 6 considered these aspects of language while investigating social perspective taking in children with generalized seizures.  Chapter 5 results indicate that children with epilepsy demonstrate deficits in semantic and syntactic language and social perspective taking compared to their same aged peers.  Chapter 6 examines language and social perspective taking in a social problem-solving context in children with generalized seizures and children with and without language problems.  The results showed that children with epilepsy demonstrate language comparable to children with language problems and that they show the worst social perspective taking for the two easiest aspects of social problem solving (problem identification and strategy generation) compared to children with and without language problems.  Language accounts for some, but not all, of the difficulties that children with generalized seizures experience in social perspective taking during social problem-solving.  Research and clinical implications of the four studies are discussed in chapter 7. The research reported on here indicates that more research is needed to determine profiles of language specific to clinical variation in childhood epilepsy. Moreover, interventions designed to promote social perspective taking are needed to strengthen the interpersonal relationships of these children.

abstract: PhD


title: Teaching Places: possibilities and challenges of unsettling education in British Columbia, Canada

contributor:
Godlewska, Anne
Geography and Planning

rights: Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada

rights: ProQuest PhD and Master's Theses International Dissemination Agreement

rights: Intellectual Property Guidelines at Queen's University

rights: This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Place
Education
Unsettling education
Settler colonialism
Colonial geographical imaginary

abstract: This dissertation draws together Indigenous, anticolonial, and place scholarship with recent work on ontological pluralism to consider the possibilities and challenges of unsettling place pedagogy in Canada. Recently, scholars have begun to express the decolonizing potential of place-based ontologies. Place in such work is not a static, rigidly bounded site of insular identity and hostility towards diversity, nor ‘the local’ scale in a ‘local-global’ binary. Rather, place gives form and expression to the inter-relationality amongst human and more-than-human co-existents. In this understanding, ontologies, politics, and education do not just take place in place, but through and as place, and place has many lessons to teach non-Indigenous and settler peoples. Such an understanding counters the liberal Western ontology deeply embedded within settler colonialism. Settler societies secure their futurity by reproducing a colonial ontology and geographical imaginary. This imaginary of land as ‘empty’ until given meaning as territory, exploitable resources, nature, and property perpetuates the dispossession and displacement of Indigenous peoples and denies the unique creative and educational powers of every place. This dissertation illustrates the role of formal education in British Columbia, Canada in the reproduction of settler-colonial ontologies, explicating some possibilities and challenges for unsettling education by and through place. I studied the roll-out of a new K-12 curriculum in BC (2015-2019) by undertaking textual analysis of the curriculum documents and conducting interviews with educators (n=17) in the Cariboo-Chilcotin region of BC. Results from these studies demonstrate that, while the curriculum emphasizes localized and Indigenized pedagogies, settler-colonial ontologies continue to pervade curricula and impact pedagogical delivery. However, place substantially influences what and how students might learn. Place fundamentally shapes the on-the-ground realities of education delivery through challenges like rural/urban and regional disparities, remoteness, and underfunding of high-Indigenous population regions. Place also offers opportunities for co-embodied, co-emplaced, and inter-relational learning amongst human and more than human co-existents. I argue the importance of attending to place for unsettling education: countering the settler-colonial tendencies of formal education and developing unsettling, situated, and open ontologies for relationships of co-becoming amongst Indigenous and more-than-human co-existents of and through place.

abstract: PhD


title: Participatory Community Asset Mapping for Rural Youth Mental Health in Wellington County, Ontario

contributor:
Masuda, Jeffrey
Kinesiology and Health Studies

subject:
Health Promotion
Mental health
Youth
Rural
Therapeutic Landscapes

abstract: Context and Purpose: In Canada, the mental health of youth has become a growing cause for concern as many young people are unable to access adequate services and are left to deal with the negative consequences of untreated mental illnesses. In health promotion, a promising direction to understanding what youth need to support their mental health and wellness is to employ participatory methods that empower youth and ensure their voices and experiences are accounted for in policies and programs. The purpose of this thesis was to investigate the perspectives of available mental health “assets” among youth living in the predominantly rural context of Wellington County in Southwestern Ontario. Methods: Recruiting a team of six youth through local partnerships, we engaged in a series of asset mapping sessions to locate places in Wellington County that are supportive of their mental health. I also conducted several interviews with both the youth researchers and community service providers to get their perspectives on both the findings of the asset mapping sessions as well as on Wellington County’s capacity to support youth mental health. Findings: The youth researchers found that informal everyday sources of support like outdoor outlets, engaging in exercise, and spending meaningful time with others are important for their wellbeing. Both the youth researchers and community service providers agreed that in the past, Wellington County has not always been the best place for youth mental health in terms of support, but they believe recent community-wide changes in attitudes towards mental health make them hopeful for the future. Implications: Our findings support the view that place-based strengths can be a part of community solutions for improved health and wellbeing for youth. Our study adds to the evidence on how health and wellbeing supports are not only be experienced in clinical or professional settings, but that seemingly ordinary everyday community interactions also have the power to help our young people thrive mentally.

abstract: M.Sc.


title: Neurobiomarkers of Real-World Dietary Success

contributor:
Tusche, Anita
Psychology

rights: Attribution-NonCommercial-ShareAlike 3.0 United States

subject: dietary decision-making

subject: functional magnetic resonance imaging (fMRI)

subject: neuroanatomy and neural function

subject: body mass index (BMI)

subject: baseline and regulatory food choices

abstract: Why do some people regularly eat healthy foods, while many others suffer poor health outcomes due to maladaptive dietary choices? Empirical work suggests that functional and structural properties of the brain contain meaningful information about a person's ability to align their dietary behaviours with higher health goals. In previous magnetic resonance imaging (MRI) studies, brain structure and function in two regions of prefrontal cortex (PFC) were linked to individual differences in 'dietary success' in laboratory food tasks (Han et al., 2018; Schmidt et al., 2018; Tusche and Hutcherson, 2018). These regions were dorsolateral prefrontal cortex (dlPFC) and ventromedial prefrontal cortex (vmPFC). Both regions have long been known to play a role in food choices (Hare et al., 2009; 2011) by influencing valuation and self-control processes during dietary decision-making (Motoki and Suzuki, 2020). Function and structure in dlPFC and vmPFC are indicators of people's choice behaviour in laboratory food tasks, and so are construed as 'neurobiomarkers' of dietary success. But to what extent can these neurobiomarkers predict real-world dieting outcomes, and which are the strongest predictors? In the current study, we tested whether brain function and structure in these 'dietary success' regions could predict a proxy measure of successful dietary behaviour, namely body mass index (BMI). In a novel approach, we estimated subjects' BMI scores in an out-of-sample predictive analysis. In a single model, we combined neural activity and cortical thickness in dlPFC and vmPFC and tested the relationship between these neurobiomarkers and subjects' BMI scores. We found that the best prediction of BMI relied exclusively on neural activity in dlPFC and vmPFC. Moreover, the prediction was strongest when subjects made natural, autonomous food choices without any task-imposed goals or considerations. These results shed new light on how brain function and structure related to food choices in the laboratory can extend to predict BMI, an outcome of real-world dietary behaviour.

abstract: M.Sc.


title: Hydrogen Fluoride Capture and Mechanisms of Adsorption by Smelter Grade Alumina at Elevated Temperature

contributor:
Davis, Boyd
Pickles, Christopher
Mining Engineering

subject:
Hydrogen Fluoride
Smelter Grade Alumina
Retention Mechanisms
Aluminum Electrolysis
HF Adsorption
Elevated Temperature
Structural Hydroxyls

abstract:
Aluminum metal is produced industrially by electrolysis of Smelter Grade Alumina (SGA) in a molten electrolyte using the well-known Hall-Héroult process. Water and structural hydroxyls associated with the SGA, and moisture from ambient air drawn into the electrolytic cell, hydrolyze the fluorides present in the electrolysis cell to produce HF gas. HF emissions from electrolytic cells are dry adsorbed (captured) onto the surface of primary alumina via a Dry Scrubbing System (DSS) followed by the subsequent recycle of the alumina, containing the adsorbed fluorides (secondary alumina), back to the electrolytic cell as feed material for the smelting process. Emission compliance is achieved by limiting the off-gas temperature entering the DSS to sustain an acceptable adsorption efficiency. This practice increases the moisture loading to the cell; hence, conventional DSS technology and operating practices promote, not abate, HF formation. This research thesis focused on understanding better the adsorption and retention of HF by alumina at both conventional and elevated temperatures. The goals were to minimize or eliminate the conflict associated with current operating practices, and to increase the alumina quality entering the electrolysis cell. Scientific observations and new discoveries from this investigation provided insight into resolving this conflict, specifically:
i. regardless of the capture temperature, HF capture capacity increased directly with the number of accessible SGA pore reaction sites.
ii. HF retention capability increased directly with capture temperature, number of accessible hydrate-free reaction sites, and the formation of stable fluoride species.
iii. principle mechanisms for HF capture included hydrogen bonding (for initial capture) followed by progressive chemisorption, provided sufficient activation energy was available.
iv. principle mechanisms for HF loss included the progressive release of hydrogen bonds above 200 °C in conjunction with hydrolysis of chemisorbed fluorides above 300 °C.
v. gibbsite soak calcined at a temperature between 250 °C and 300 °C, before reacting with HF, provided the optimal HF capture capacity and retention capability.
HF capture at elevated temperature, when coupled with increased accessible pore specific surface area, has the potential to reduce HF emissions to the environment, and increase the alumina quality entering the electrolysis cell.

abstract: PhD


title: MODELING SPECIES ABUNDANCE WITH IMPERFECT DETECTION USING ANGLING

contributor:
Tufts, Bruce
Ridgway, Mark
Biology

subject: Occupancy Abundance Fish Angling Loughborough

abstract: Modeling species abundance and predicting species distribution are important tools for fisheries management. Advanced modeling techniques have allowed for predictive models with increased accuracy to be developed because of their ability to account for imperfect detection. Novel sampling methods have been created to sample aquatic environments such as large bodies of water that cannot be easily sampled by traditional fisheries methods. I surveyed Loughborough Lake near Kingston, Ontario to develop abundance models that would predict species distribution based on depth and fetch habitat variables using angling as the sampling method. Loughborough Lake is a 2000-hectare lake that has interesting bathymetric and limnological characteristics with two distinct basins. An angling protocol was developed to be able to sample all environments of the lake while being able to efficiently sample sites. Abundance modelling was completed for Largemouth Bass, Smallmouth Bass, Rock Bass, Pumpkinseed, Bluegill and Yellow Perch.  Results showed that a broad distribution of centrarchid species, and other species, was not observed throughout Loughborough Lake. In contrast, centrarchid distribution was characterized as basin-specific in nature with different species occupying either the eastern or western basin. This pattern was unexpected, but it may be explained by variation in fetch, which functions as a surrogate for vegetation. Angling was found to be an effective method that allowed an individual sampler to efficiently obtain count data. The valuable information gained from the combination of the abundance models and a novel sampling method could improve sampling programs and aid in future research.

abstract: M.Sc.


title: Calibration and background data analysis in the scope of the NEWS-G dark matter experiment

contributor: Physics, Engineering Physics and Astronomy

subject:
dark matter
NEWS-G
spherical proportional counter
SPC
WIMP

abstract:
The NEWS-G experiments aims at the discovery of low mass dark matter, using spherical proportional counters filled with gas. The latest detector, a 140-cm diameter copper sphere, has collected data in the Fall of 2019 at the Laboratoire souterrain de Modane (LSM) as a preparation for its future operation at SNOLAB starting in 2021. A paper from this data is in the final stages of preparation, and this thesis describes my work related to data analysis.
More concretely, this thesis first explores the sphere conditions that affect the electron drift time. Then, it looks at the effect of alpha contamination and how the related background can be cut from the data. Finally, it shows how spike events can be identified and removed from the event selection.

abstract: M.Sc.


title: Combinatorial Optimization and Schedule Generation Using Deep Bipartite Assignment

contributor:
Rivest, Francois
Givigi, Sidney
Computing

rights: Attribution-ShareAlike 3.0 United States

subject:
AI
Machine Learning
Combinatorial Optimization
Operations Research
Scheduling
WTA
NSP
Nurse Scheduling Problem
Deep Reinforcement Learning
Deep Learning
Attention
Bipartite Assignment
Assignment Problems
Neural Networks

abstract: Recent advances in deep reinforcement learning (DRL) have allowed it to contribute to areas which were previously the domain of traditional algorithms. Operations research (OR), however, has lagged behind in this respect. OR problems often involve data with properties that are difficult for deep learning techniques to handle, and there is a concomitant lack of background research to draw from when designing new DRL approaches in this area. A 2019 paper introduced Deep Bipartite Assignment (DBA), a neural network architecture which allows DRL to be applied to simple bipartite assignment problems such as the Weapon-Target Assignment problem (WTA). In this work, we accomplish two objectives. First, we demonstrate that DBA can be extended to address more complex scheduling problems, including the Nurse Scheduling Problem and the Spatio-Temporal WTA. Second, we use DBA as a starting point to research the effects of various design choices on performance when solving scheduling and assignment problems using DRL. We identify patterns in hyperparameter choice, network structure, and training algorithm choice which can be used by future researchers to design better performing DRL agents for OR problems.

abstract: M.Sc.


title: CARBONACEOUS FILLER INCORPORATION IN IMIDAZOLIUM-BASED IONOMER COMPOSITES

contributor:
Parent, J. Scott
Chemical Engineering

subject:
Ionomer
Imidazolium-Based Ionomer
Carbonaceous Filler
Carbon black
Graphite

abstract:
Three carbonaceous fillers were compounded into an elastomeric ionomer and assessed using dynamic mechanical analysis, static tensile analysis, and electrical conductivity. Carbon black, flaked graphite and an expanded graphite product, MesografTM, produced by Grafoid Inc. were mixed into the elastomer in different loadings to evaluate their potential to reinforce the material and affect the dynamics and yields of peroxide cure chemistry.
In an attempt to produce an unconventional distribution of filler in the polymer matrix, artificial latexes where prepared with the elastomer comprising the dispersed phase in a continuous phase of water. The addition of filler to these emulsions confined it to the aqueous phase and polymer/water interface, with none entering the polymer phase.  Drying the resulting emulsions produced composites with filler located in a segregated network.  Analysis of these composites by mechanical and conductivity show differences between this non-uniform filler distribution and the uniform distributions produced by conventional rubber compounding approaches.

abstract: M.A.Sc.


title: Unsettling Geography: Exploring Truth and Reconciliation in Geography Departments at Canadian Universities

contributor:
Castleden, Heather
Cultural Studies

subject:
Truth and Reconciliation
Indigenous-settler relations
Settler colonialism
Neoliberal academy
Space-time geographies
Geographies of white supremacy
Decolonization
Foucauldian discourse analysis

abstract: From the onset of colonial exploration, professional and scholarly geographers have played a prominent role in establishing the systems of colonial and imperial expansion embedded in Indigenous dispossession and genocide, white settler supremacy and justified occupation on stolen Indigenous Lands. The discipline’s relationship to colonial and imperial power is not a thing of the past, Geography remains implicated in ongoing white settler colonialism. Given the discipline’s historical culpability and ongoing complicity in settler colonialism, Geography Departments at Canadian universities are situated in a unique position to implement the 2015 Truth and Reconciliation Commission’s (TRC) Calls to Action, decolonize the discipline, and reconcile their relationships to Indigenous peoples and the Land. The goal of my research was to understand the extent to which the TRC’s Calls to Action are understood and operationalized in Geography Departments and the discipline as a whole across Canada, and to identify any perceived barriers to engaging with the TRC’s recommendations in the Departments’ curricular, pedagogical, and or administrative spheres. What I found was that while Geography Department Heads stated that they had a responsibility to implement the Calls to Action, much of what had been achieved in Departments thus far is of a superficial scale. Moreover, there was great uncertainty as to when, the extent of time committed, and how Geography Departments would proceed in formalizing strategic frameworks to implement the TRC’s recommendations and decolonize the discipline. This thesis offers that operationalizing the Calls to Action and reconciling the discipline’s relationship to Indigenous peoples and the Land necessitates a decolonization of white settler-colonial market time, which is a single, homogenized, and western linear temporality structured on settler colonialism, capitalist modes of operation, and lifeforms that orient towards a white settler futurity. This thesis calls upon non-Indigenous settler geographers who occupy Geography Departments to take time away from their ‘status quo’ agendas and use that time to devise and implement plans that respond to the Calls to Action and advance the processes of reconciliation, decolonization, and Indigenization across the discipline.

abstract: M.A.


title: The effect of a single session of acute mindfulness meditation on endothelial function

contributor:
Pyke, Kyra
Kinesiology and Health Studies

subject:
mindfulness
meditation
vascular endothelium
cardiovascular health
endothelial function
autonomic nervous activity
Eastern practices
wellbeing
physiology
contemplative science

abstract: Mindfulness meditation (MM) is associated with some improvements in cardiovascular health in addition to mental wellbeing. Vascular endothelial function, an indicator of overall cardiovascular health, is influenced strongly by sympathetic nervous activity that is altered by acute meditation. Only a few studies have noted that mindfulness improves the vascular endothelium after chronic mindfulness programs, however it is still unknown to what degree a single acute session of MM may affect endothelial function especially in young, healthy subjects. We hypothesized that an acute MM session would transiently improve endothelial function. Secondarily, we sought to characterize the meditative state using electroencephalography (EEG) to measure brain activity, heart rate variability (HRV) to measure autonomic activity, and MM questionnaires to assess subjective state mindfulness. Twelve healthy young adults (21 ± 2 years) with no meditation experience participated in two experimental visits each involving a 20-minute MM condition or an active control condition. We assessed endothelial function before and after each condition using reactive hyperemia-induced flow-mediated dilation (RH-FMD). We did not detect a change in endothelial function after MM or the active control (RH-FMD: p = 0.582), and MM did not stimulate an increase in EEG alpha power or HRV (alpha power: p = 0.568; HRV: p = 0.395). The subjective MM questionnaire revealed no change in state mindfulness after either condition (p = 0.800). We also correlated RH-FMD with both EEG alpha power and HRV during MM and found no significant relationships (RH-FMD versus alpha power: r2 = 0.39, p = 0.054; RH-FMD versus HRV: r2 = 0.39, p = 0.086). The secondary measures did not confirm that the subjects achieved the intended meditative state. It therefore remains unclear whether a successful MM can acutely improve endothelial function. The type of MM employed in an acute session may be the most critical factor for generating both cognitive and physiological effects in novice meditators. Further research is needed to determine whether a meditative state can transiently affect vascular endothelial function.

abstract: M.Sc.


title: The toxic effects of oil sands contaminants on fish

contributor:
Orihel, Diane
Biology

subject:
Ecotoxicology
Fish
Sublethal effects
Behaviour
Field study
Mesocosms

abstract:
Extracting bitumen from the Canadian oil sands is a water-intensive process that
produces large volumes of oil sands process-affected water (OSPW). The recycling of OSPW for
bitumen extraction causes it to become highly contaminated with salts, metals, residual bitumen,
and dissolved organic compounds called naphthenic acid fraction components (NAFCs).
Currently, large volumes of OSPW are being stored in temporary settling basins called tailings
ponds. As OSPW is known to be toxic to a variety of organisms, there is increasing concern
about accidental breaching and leaking of OSPW from tailings ponds into the environment. To
mitigate these risks, there are plans for controlled releases of treated OSPW into surrounding
environments. More information on the sub-lethal effects of OSPW, and particularly NAFCs
derived from OSPW, is needed to inform regulations that will protect wildlife and human
populations living downstream of the oil sands region. Our studies evaluated whether exposure
to NAFCs extracted from OSPW has lethal and sub-lethal effects on fish. Our first study exposed
fathead minnow (Pimephales promelas) embryos to environmentally relevant concentrations of
NAFCs (2 - 54 mg/L) for 7 days, then raised surviving larvae in outdoor mesocosms of clean
lake water for 1 month. We found that embryonic exposure to NAFCs resulted in decreased
embryo survival and impaired development, with persistent adverse effects on larval fish
survival and behaviour after one month of rearing in lake water. Our second study exposed
juvenile yellow perch (Perca flavescens) to environmentally relevant concentrations of NAFCs
for 7 days and monitored the fish for changes in behaviour before and after NAFC addition. We
found that juvenile exposure to NAFCs (15 mg/L) impaired fish survival, fish equilibrium while
swimming, and antipredator behaviour in fish. Our findings show that NAFCs have both lethal
and sub-lethal effects on fish development and behaviour that could affect their survival and
performance following exposure. These findings are pertinent for developing evidence-informed
decisions regarding planned OSPW releases in the Canadian oil sands region.

abstract: M.Sc.


title: Early Substance Use and Later Depressive Symptoms Among Canadian Adolescents: Examining the Association Using Intersectionality Theory

contributor:
Davison, Colleen
Public Health Sciences

subject:
adolescence
substance use
depression
intersectionality theory
epidemiology

abstract:
BACKGROUND: Growing evidence suggests adolescent substance use may lead to depression and earlier initiation may be especially problematic. Social identities or positions defined by such factors as gender, race, or socioeconomic status (SES), have been associated with adolescent substance use and depression; however, their effects have primarily been examined independently, whereas Intersectionality Theory emphasizes the potential synergistic effects of multiple aspects of individual identity.
OBJECTIVES: First, to describe early substance users (<14 years) in Canada while considering intersecting social positions by gender, race, and SES; second, to examine the association between early substance use and depressive symptoms later in adolescence; and third, to investigate differences in this relationship at varying intersections of gender, race, and SES.
METHODS: Data were from the 2017/2018 Canadian Health Behaviour in School-aged Children study, providing a nationally representative sample of adolescents in grades 9 and 10. Descriptive and multilevel, multivariable modified Poisson regression analyses were performed to estimate the relative risks for the association between early substance use and later depressive symptoms. Multiplicative interaction and stratification by two- and three-way combinations of gender, race, and SES were used to assess effect modification.
RESULTS: Nearly one in four (23.5%) adolescents reported early substance use, and this proportion differed significantly across subgroups at intersecting social positions, with subgroups that included lower SES generally displaying a greater proportion of reported early substance use. The risk of depressive symptoms was significantly higher among those who reported early substance use compared to those who did not (RR 1.23; 95% CI 1.16-1.31). Combinations of gender, race and SES were not found to modify the relationship between early substance use and depressive symptoms; post hoc power calculations indicated that there was insufficient power to detect interacting effects between intersecting social positions and early substance use in predicting later depressive symptoms.
CONCLUSION: Preventing substance use in early adolescence, such as by delaying substance use initiation, may help prevent depression overall in youth. As the proportion of reported early substance users differed by subgroups of intersecting social positions, interventions aimed at preventing early substance use should use a targeted, intersectional approach.

abstract: M.Sc.


title: Impact of Reinforcement Learning Enabled Smart Homes on Humans

contributor:
Etemad, Ali
Rivest, Francois
Electrical and Computer Engineering

subject:
Reinforcement Learning
Smart Homes
Human Model
User Recognition

abstract:
Smart homes are becoming increasingly popular as a result of advances in machine learning and cloud computing. Devices such as smart thermostats and speakers are now capable of learning from user feedback and adaptively adjust their settings to human preferences. Nonetheless, these devices might in turn impact human behavior. To investigate the potential impacts of smart homes on human behavior we simulate a series of Hierarchical-Reinforcement Learning-based human models capable of performing various activities namely setting temperature and humidity for thermal comfort inside a Q-Learning-based smart home model. We then investigate the possibility of the human models' behaviors being altered as a result of the smart home and the human model adapting to one another. We then integrate our human model in the environment along with the smart home model and perform rigorous experiments considering various scenarios involving a single human model and two human models. Our experiments show that with the smart home, the human model can exhibit unexpected behaviors like frequent changing of activities and an increase in the time required to modify the thermal preferences. With two human models, we interestingly observe that certain combinations of models result in normal behaviors, while other combinations exhibit the same unexpected behaviors as those observed from the single human experiment.

Given that the smart home model uses parameters like temperature, humidity, and activity to learn the user's thermal preferences, it lacks personalization for the occupant. To address this, we modify our smart home model to obtain a partially observable smart home system based on the partial-observable Markov decision process, where the state of the human model is unknown. The smart home maintains a belief over each possible human state to approximate the hidden human state using its thermal parameters. Subsequently, it learns the personalized thermal preference of multiple human models.  We demonstrate that our improved model can reasonably approximate up to 5 occupants and also learn their thermal preferences with incomplete state information. Our simulated experiment achieves classification accuracies of 0.98, 0.91, 0.76, and 0.67 for 2 to 5 human occupants in the smart home.

abstract: M.A.Sc.


title: Fighting the raging beasts' blaze: Examining the effect of framing in wildfire news reports on risk perception

contributor:
Bisung, Elijah
Kinesiology and Health Studies

subject:
wildfires
risk perception
metaphors
natural disasters
framing

abstract:
Research regarding message framings and risk perception for wildfires in a Canadian context is scarce. The sparseness of such research is disheartening, especially in an era when climate variability seriously affects wildfire severity and frequency and the associated changes in peoples’ perception of their relative risk to the fires. The purpose of this research is to explore different wildfire framings in local British Columbian (B.C.) media and how these framings influence individual risk perceptions and behavioural intentions.

Local news report headlines and opening statements for imminent wildfire events are often dominated by metaphoric framings, especially with antagonistic connotations. While these metaphors are often utilized as a conceptual tactic to be interpreted by the public more concretely, little research has been conducted as to whether this tactic informs the public in a healthy, adaptive way. The first part of this thesis (study one) is a media analysis of current message framings for wildfires and their associated health risks, using 161 online news reports in B.C. Findings show that the most common framings were metaphorical and statistical and, more scarcely, health risk related. The most common framings were used to develop vignettes to examine local wildfire perceptions (study two).

Following the media analysis, study two involved the use of an online survey (n = 206) to assess individual risk perceptions and behavioural intentions about three hypothetical wildfire scenarios framed with metaphors, statistics, or health risks. The results show that wildfires described with metaphors and statistics led community members to perceive wildfires as more severe. The statistical framing also led community members to perceive wildfires as more concerning, and women typically had higher ratings of concern and intentions to engage in health-protective behaviours. Findings from this research will contribute to the growing body of health and emergency communication literature. In collaboration with knowledge translation leads at the Interior Health Authority in B.C. (IHA-BC), preliminary findings will be shared with local public health units and emergency services to advocate for the most apt wildfire messaging strategies.

abstract: M.Sc.


title: Protection of Human Rights in the International Investment Regime: A Critical Survey with a view into the Iranian Foreign Investment Experience

contributor:
Karton, Joshua
Law

subject:
Investment Law
International Investment Law
Bilateral Investment Treaties

abstract: Considering that the main purpose of attracting foreign investment is the economic development of the host states, as well as profit of the foreign investors, this purpose cannot be achieved, at least not over the long term, by infringing the human rights of the host states. The Islamic Republic of Iran is a large country with rich natural resources which require foreign investment to develop its resources. On this basis, exploring the economic development of the Iranian state, as an investment host state, and reflection of human rights protection in the investment law regime of Iran, have significant importance. For this aim, this research examines the provisions of the Iranian effective BITs and applicable domestic human rights laws on foreign investors to find out to what extent the existing Iranian investment law regime protects the human rights law obligations of the Iranian state vis-à-vis its obligations toward foreign investors. Iran, as a respondent state in investment arbitration, could take human rights arguments whether for justifying measures undertaken in compliance with international or domestic human rights law, or for invoking violations of its domestic human rights law by the foreign investors. This research finds out that refining the pro-investor approach of Iran’s current treaties will effectively address the tensions between human rights and investment norms. Drafting a new model agreement with human rights consideration and renegotiating the existing investment treaties with counterparties—the major trading partners in priority—could help the Iranian state to establish an equilibrium between protection of foreign investors and its regulatory power for protecting the human rights of the Iranian citizens, and finally achieve its desired economic development in the long-term.

abstract: LL.M.


title: Spatial ecology of two Lake Whitefish (Coregonus clupeaformis) spawning aggregations in eastern Lake Ontario

contributor:
Tufts, Bruce
Biology

subject:
Lake Whitefish
Acoustic Telemetry

abstract: Lake Whitefish (Coregonus clupeaformis) in the Laurentian Great Lakes have experienced major ecological changes and overexploitation by commercial fisheries throughout the past century. In Lake Ontario, the Lake Whitefish population was severely reduced and has shown minimal reproductive success since the 1990s. In Canadian waters, two major spawning aggregations persisted in the eastern basin, one in the Bay of Quinte and the other in Lake Ontario, and currently support a commercial fishery. At the present time, there is an urgent need for more research on this species in Lake Ontario to better understand the impacts of ecological changes and to ensure that the commercial fishery is sustainable. Using acoustic telemetry, this study analyzed the spatial distribution and movement patterns of Lake Whitefish in eastern Lake Ontario to determine whether the two spawning groups were spatially discrete. A total of 57 Lake Whitefish were tagged with acoustic transmitters between 2016 and 2018. Spatial analysis revealed clear differences in space use between the spawning aggregations. Lake Whitefish from the Bay of Quinte spawning group occupied the northwestern area of the eastern basin and did not leave the eastern basin, whereas Lake Whitefish from the Lake Ontario spawning group mainly occupied the southeastern area of the eastern basin and moved outside the eastern basin. Mixing of the spawning groups did not occur during the spawning season and was minimal at other times of the year in the northwestern area of the eastern basin, primarily in August and September. This provided insight into the relative harvest of the spawning groups by the commercial fishery in spring and summer when the groups are not spatially isolated at spawning grounds in the fall. Differences in seasonal distribution were also observed for both spawning groups and provided insights into what factors may have influenced habitat selection. In summary, the spatial discreetness observed between the spawning aggregations suggests differences may exist in commercial exploitation and factors related to habitat use such as diet and energy expenditure. Although there is still a need for further research in these areas, this study has provided valuable insights for the management and conservation of this species in Lake Ontario.

abstract: M.Sc.


title: Quenching factor measurement of neon nuclei in neon gas and study of the feasibility of detecting coherent elastic neutrino-nucleus scattering at a nuclear reactor using a spherical proportional counter

subject: Detector Calibration

subject: Particle Physics

subject: Dark Matter

subject: Coherent Elastic Neutrino-Nucleus Scattering

abstract:
The NEWS-G collaboration uses Spherical Proportional Counters (SPCs) to search for weakly interacting massive particles (WIMPs) through direct detection. Due to their sensitivity to single electrons from ionization, SPCs are also considered for the detection of neutrinos via coherent elastic neutrino-nucleus scattering (CE$\nu$NS). We study the feasibility of an experiment conducted near a nuclear reactor, and provide estimates of the CE$\nu$NS event rate in four different targets, and provide preliminary event rates of backgrounds from materials intrinsic radioactivity. From these calculations, we propose xenon and argon as viable targets for a CE$\nu$NS experiment with SPCs at a nuclear power plant. \\
\indent The detection of low-energy nuclear recoils induced by both CE$\nu$NS and WIMPs presents several challenges. One of them is the energy calibration to nuclear recoils in the sub-keV region. We explored the feasibility of measuring the nuclear quenching factor of neon nuclear recoils induced by a neutron beam, produced at the TUNL facility, in an SPC filled with \SI{2}{bar} of Ne+CH$_4$ (\SI{3}{\%}). A new analysis technique was developed to extract the quenching factor between 0.43 and \SI{11}{keV_{nr}}, by implementing a Bayesian analysis framework and simultaneously fitting multiple data sets recorded during the experimental campaign. The energy dependence of the nuclear quenching factor is modelled using a simple power law: $\alpha$E$^{\beta}_{nr}$, whose parameters were measured to be $\alpha$ = 0.2801 $\pm$ 0.0050 (fit) $\pm$ 0.0045 (sys) and $\beta$ = 0.0867 $\pm$ 0.020 (fit) $\pm$ 0.006 (sys). These measurements provide the first estimation of the nuclear quenching factor in neon gas.

abstract: PhD


title: Characterization of dissolved fluvial carbon from landscape characteristics across High Arctic headwater streams

subject: Arctic

abstract: Stream runoff is an important conduit of carbon from the terrestrial ecosystem to the Arctic Ocean, where fluvial carbon is a product of both the source and pathway of the stream network through a watershed. Small headwater streams in the High Arctic are understudied and account for a significant amount of the freshwater geochemical flux from North America. This research investigates the concentration of fluvial dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) across High Arctic streams in order to understand the role of landscape characteristics on carbon transfer from High Arctic watersheds to the Arctic Ocean. Water chemistry data were obtained from 146 streams across four regions on Axel Heiberg Island, NU and the Sabine Peninsula on Melville Island, NU. Different landscape characteristics were identified and characterized across watersheds including terrain features (watershed area, elevation, slope, aspect), hydrology (stream length, stream order), vegetation cover, permafrost disturbances, glacier presence, and geology. Landscape drivers of fluvial carbon vary based on the specific sampling location due to the heterogeneity of the High Arctic landscape, although some trends do emerge. Vegetation cover was identified as a driver of DOC; DOC concentration increases with increasing vegetation coverage. The presence of limestone rock and evaporite rock increases DIC concentration. Vegetation cover and elevation were identified as drivers of DIC; DIC concentrations increase with increasing vegetation cover or decreasing elevations. Regression analyses were conducted to develop models of DOC and DIC concentration across the heterogenous landscape of the Northern Canadian Arctic Archipelago. Vegetation cover, north-south aspects, and elevation provided the greatest significant (p < 0.05) correlations in the regression models. This study helps further the understanding of sources and drivers for fluvial carbon concentrations in the High Arctic and when coupled with stream discharge measurements will aid in the modeling of carbon flux from land to the Arctic Ocean.

abstract: M.Sc.


title: A Framework for Modeling Advanced Persistent Threats in Intelligent Transportation Systems

contributor:
Zulkernine, Mohammad
Computing

subject:
Advanced Persistent Threats
Intelligent Transportation Systems
Cyber Physical Systems
Game Theory
Stackelberg Game for ITS Security
threat modeling
APT

abstract: An Intelligent Transportation System (ITS) is the embodiment of a vast and connected network that leverages connectivity for more efficient transportation. This is through congestion management, collision avoidance, and reduction of greenhouse emissions with open and rapid sharing of large amounts of data. However, there has been a lack of focus on the security of the ITS. Unfortunately, the underlying mechanics that enable the functions of the ITS also create easily exploitable attack vectors. These attacks can result in critical damage. Furthermore, the data exchanged over the ITS network is easily corruptible with attacks known as misbehaviours. The development of misbehaviour detection systems has gained traction within the research community recently. Detectors that are specialized for specific types of attacks have been developed but are siloed, and lack consideration of attacks that are multifaceted, and an amalgamation of individual attacks. These are carried out by threat actors, known as Advanced Persistent Threats (APTs), that wish to cause long-term impact using much more dangerous and difficult to detect misbehaviours. Modeling APTs infrastructures has been done successfully using game theory in other critical infrastructures similar to the ITS. In this work, we present a framework for designing APTs and redefining their lifecycle within the ITS, and by extension for other cyber physical systems. Using this definition, a Stackelberg game is designed for modeling the motivations and behaviours of APTs within the ITS. Unconventionally, the APT attacker is defined as the leader in this game, as opposed to the defence application, given the asymmetry of information in the APT's favour. The optimization problems of the attacker and the defence system are derived, which outline the objective functions of each. A use-case scenario is used to demonstrate how to apply the framework in an ITS setting. Our work shows the impact an intelligent and evasive attacker can have on the system and the insufficiency of current state-of-the-art detectors in identifying these types of attacks. This model can be customized to any given APT targeting the ITS and will help model APTs more realistically, to subsequently better protect ITSs against them.

abstract: M.Sc.


title: Associations Among Self-Reported Tick-Borne Disease Symptoms, Treatments & Diagnoses

contributor:
Colautti, Robert
Egan, Rylan
Biology

subject:
Lyme disease
Tick-borne disease
Self-reported symptoms
TBD
Eastern Ontario
Canada
Tick-borne disease comorbidities

abstract: In eastern Canada, deer ticks (Ixodes scapularis) carry a variety of bacterial (Borrelia burgdorferi, Anaplasma, Ehrlichia, Rickettsia) and protozoan pathogens (Babesia) that are responsible for more disease in humans than any other arthropod vector. While most known tick-borne diseases (TBD) in Canada are treatable, invasions of new pathogens may go undetected. Misdiagnosed and untreated infections can cause debilitating symptoms, many of which are non-specific and can be mistaken for other diseases. Using quantitative models, the goal of my thesis is to investigate whether tick-borne diseases cause syndromes (e.g., groups of symptoms which consistently occur together). An anonymous cross-sectional survey was disseminated online via the Qualtrics software package to survey age, gender, blood test results, symptom profiles, and chronic health conditions. Recruitment was focused on the Kingston-Ottawa corridor because it is a Lyme disease hotspot in Canada, but inclusion criteria included anyone with a self-reported tick bite. This resulted in 1248 unique submissions, 301 of which self-reported a tick-borne disease. On average, participants who reported a Lyme disease diagnosis along with one or more secondary co-infections presented with more symptoms and a longer time to diagnosis than participants with Lyme disease alone. I used supervised machine learning to model self-reported symptoms while accounting for demographics, clinical tests, and chronic health conditions. A Regularised Discriminant Analysis of 13 binary symptoms correctly classified participants with 98% accuracy into self-reported diagnoses grouped into four categories: Lyme disease, Lyme disease with one or more co-infections, other tick-borne disease, and no diagnosed disease. To model how healthcare practitioners might diagnose disease, I used hierarchical logistic regressions to identify self-reported factors that predict diagnosis. Skin rash and blood tests were predictive of all three diagnosis categories, accounting for 41-61% of the variation in TBD diagnosis predictions. Participants with chronic health conditions (cardiovascular, rheumatological, and central nervous system disorders) were less likely to receive TBD diagnoses, which is consistent with misdiagnosed disease. This research shows that symptom profiles can be used to understand tick-borne diseases. A collaborative research approach between scientists and patients such as this one can improve diagnosis and knowledge translation in the domain of TBD.

abstract: M.Sc.


title: Numerical Restrictions on Seshadri Curves, with Applications to P^1 x P^1

contributor:
Roth, Mike
Mathematics and Statistics

subject:
Mathematics
algebraic geometry
Seshadri constant

abstract: We study r-point Seshadri constants on smooth surfaces. The Seshadri constant is bounded above by the Nagata bound, and in cases where it is not maximal this fact is witnessed by a set of curves which we call Nagata curves. In Chapter 2, we study the properties of Nagata curves, especially the set of necessary conditions on the numerical class of a Nagata curve found in Theorem 2.6.2. In Chapter 3, we make a quick study of surfaces which are fibrations where the class of a fibre contains a Nagata curve. In Chapter 4, we develop tools to approximate Seshadri constants which allow us to improve upon known bounds in several situations. Finally, in Chapter 5, we make an in-depth study when the surface is P^1 x P^1. We compute Seshadri constants (for all values of r) for a class of line bundles, which we call outer bundles. The remaining line bundles, which we call inner bundles, are more mysterious, but we do show that their Seshadri constants are not always maximal. We then use our results about Seshadri constants for outer bundles to completely solve the symplectic packing problem for P^1 x P}^1. We end with some particular calculations for the line bundle L = (1,1).

abstract: PhD


title: ‘Aging in the Right Place’: An Analysis of the Demographic Profile and Residential Relocation Patterns of Older Adults Living in Residential Facilities in Kingston, Ontario

contributor:
Rosenberg, Mark W.
Geography and Planning

subject:
Health Geography
Geographies of aging
Residential facility
Residential relocation
Late-life migration
Older adult
Aging in place
Aging in the right place
Gerontology
Kingston
Ontario
Canada

abstract:
Despite the firm policy push for Canadian older adults (65+) to continue aging in their own homes, relocating to a residential facility (RF) continues to be both a preferred and needs-driven decision for some older adults. RFs serve as a key factor in supporting the growing older population, bridging the gap between one’s home and long-term care facilities. Understanding why some older adults choose to relocate to RFs and their geographic residential relocation patterns is critical to ensuring that these facilities can effectively support the needs and preferences of this population.
Applying the concept of ‘aging in the right place’, this thesis takes an exploratory approach to understanding the demographic profile of older adults living in RFs in Kingston, Ontario, and the geographic patterns and what influences their residential relocations. Both quantitative and qualitative analyses were performed on the questionnaire responses gathered at four RFs in Kingston (n=41). Findings on the demographic profile of the participants aligned with the literature that older adults living in RFs are healthier, wealthier, better educated, and of a White racial background. Results of the quantitative analysis revealed that the majority of participants had relocated from within Kingston, thus continuing to age in place in their community. Gender appeared to influence whether one had undergone a health-related relocation, with results of the binary logistic regression revealing that males are more likely to experience a health-related relocation than a non-health-related relocation. Applying the push and pull factor model, individuals who rated their general health as fair, those who did not own their previous dwelling, and those who previously lived outside of Kingston were all more likely to have relocated because of a pull factor. Content analysis revealed three overarching themes pertaining to the most-liked features of RF living and four themes relevant to the least-liked features.
This research highlights the existing need and desire for RFs as an option for older adults to age in the right place. The results of this exploratory research call for future research on the residential relocation patterns and demographic profile of residents living in RFs in Canada.

abstract: M.A.


title: An Assessment of Rockfall Triggers and Seasonal Weather Trends Through An Examination of Railway Slope Management Procedures

contributor: Geological Sciences and Geological Engineering

subject:
geology
rockfalls
railways
slope management
hazard
risk
weather
engineering

abstract:
Rockfalls are one of the many geohazards that impact railways across Canada with the potential to cause operational delays, damage to infrastructure and the environment, and injury or loss of life. To minimize the risk associated with these scenarios, railways rely on slope management systems that standardize assessment procedures, slope inventories, and rockfall recording methods to help understand the spatial and temporal nature of rockfall occurrences and guide mitigation decisions. This study examines the slope management systems of Canadian Pacific Rail and the Iron Ore Company of Canada and aims to provide new insight into the triggering of rockfall events through an assessment of seasonal weather trends along track segments from each of the railways.

The CPR Engineering and Management of Rock Slopes directive was designed to support the prioritization of maintenance work while the IOC Geohazard Management System was designed to conduct a life-loss assessment using a risk-based framework. This review highlighted that although intended for different goals, both systems benefitted from personnel training and participation and underlined the importance of developing standards and records to help learn about and effectively manage rockfalls.

The relationship between monthly rockfall distribution, precipitation, and freeze-thaw trends - the two primary rockfall triggers - were assessed using the von Mises modelling methodology outlined in Macciotta et al., (2017) for the HeBa (CPR) and Gagnon Sud (IOC / QNS&L) segments. The HeBa analysis was conducted using a 26-year rockfall and weather record (209 events) and resulted in a 0.92 correlation to the rockfall records, while the Gagnon Sud analysis used an 8-year rockfall record (76 events) and 5-year weather record and resulted in a 0.86 correlation. Modelling from both analyses pointed to precipitation as the primary cause for rockfall events in the summer and fall, while spring events were mostly triggered by freeze-thaw action. Comparisons to previous work in western Canada showed that the more moderate climates tended to experience peak rockfall activity in the fall or winter, depending on the degree of cooling, while HeBa and Gagnon Sud in eastern Canada experienced peak rockfall activity in the spring after a deep winter thaw.

abstract: M.A.Sc.


title: Graphene Nanoplatelets Produced by Thermomechanical Exfoliation of Graphite, and their use in Polyamide Composites

contributor:
Kontopoulou, Marianna
Chemical Engineering

subject:
Graphite
Graphene Nanoplatelet
Exfoliation
Thermomechanical
Characterization
Nanocomposites
Mechanical Properties
Multifunctional properties

abstract:
This thesis presents a new thermomechanical exfoliation (TME) method to produce graphene nanoplatelets (GNPs) from flake graphite. GNPs having specific surface area up to ~430 m2/g are produced under the action of shear forces, which serve to delaminate graphite, using a lab-scale polymer batch mixer equipped with roller rotors at a set temperature of 250 oC and 150 rpm. The corresponding energy requirement is 35-60 kJ/g for an operation that lasts 90-100 minutes. Bulk characterization showed the resulting product comprises a mixture of up to 68 wt% GNPs, the rest of it being residual micrographite. Electron microscopy images and atomic force microscopy (AFM) revealed that the lateral dimensions of the GNP flakes are 0.1 – 1.5 µm, with thickness as low as 0.9 nm, which suggests the presence of few-layered graphene with aspect ratios up to 250.
Graphite and GNPs were used as fillers in a polyamide 6,12 (PA) matrix. Graphite increased the thermal conductivity more than GNP, up to 3-fold higher than neat PA, due to its larger particle size and therefore lower interfacial thermal resistance. GNP composites had an electrical percolation threshold of ~30 wt%, and maximum electrical conductivity of 10-1 S/m, whereas graphite did not percolate. Both fillers increased the flexural modulus up to 240% and decreased the flexural strain to 20% of the neat PA, at 40 wt% filler loading. Both fillers also increased the impact strength, but 20 wt% GNP saw the largest increase of 300%, compared to neat PA. To further improve the impact strength and the flexural strain, a maleated ethylene-octene copolymer (EOC) was added to 30 wt% GNP/PA composites. The resultant blend was still electrically conductive and up to 700% tougher than neat PA.

abstract: M.A.Sc.


title: Changing Our Tune: Exploring Collaborative Songwriting with Choirs as a Process for Disrupting Traditional Eurocentric Compositional Practice, Increasing Participation in Music Creation, and Supporting Well-Being

contributor:
Renihan, Colleen
Cultural Studies

subject:
collaborative songwriting
collaborative composition
therapeutic songwriting
choral music
choral repertoire
choir well-being

abstract:
Western classical music institutions have, in recent years, been forced to contend with the weight of their long traditions of white hegemony, patriarchy, and ableism (see Kajikawa 2019; Nettl 1992; Younker 2014). While there have been discussions about the ways in which repertoire might be broadened to reflect a sense of inclusion and diversity, less has been explored vis-à-vis what a movement away from Eurocentric musical processes might look like.

This thesis reports on a research-creation project designed to reimagine the relationship between composers and singers in choirs. Whereas traditional models of choral performance focus on the reproduction of existing work, the alternative model that I designed and implemented explores the possibility that choirs can, with the help of a facilitator, self-compose music. With much choral repertoire currently reflecting its colonial, hierarchical, and Eurocentric roots, this project also aims to rethink the kind of music that choirs can sing, placing the narrative in the hands of the choir itself.

My “creation-facilitator model” reveals ways that this process of shared artistic leadership has the potential to disrupt traditional Eurocentric compositional and performance practices by dissolving the hierarchical structure usually observed between composer and performer. An Interpretative Phenomenological Analysis (IPA) of participant interviews, along with composition session observations, and e-journal entries reveal insights into participants’ perceptions of composition and creativity, along with the ways in which my creation-facilitator model may challenge traditional compositional practices. The benefits to participants of engaging in collaborative creation vis-à-vis well-being is explored, along with best practices for facilitating collaborative songwriting. Additionally, I discuss the potential of this model to create dynamic, accessible environments that encourage musical play. Finally, I present significant challenges and limitations of this work, suggesting areas of future research.

abstract: M.A.


title: Master Equations for Computing Gauge-Invariant Observables in the Ultrastrong Coupling Regime of Cavity-QED

contributor: Physics, Engineering Physics and Astronomy

rights: Attribution-NonCommercial 3.0 United States

subject:
physics
quantum optics
cavity quantum electrodynamics (QED)

abstract: The revolutionary discoveries made in quantum theory have caused a surge of technological innovation --- from the laser to the modern computer. As we gain a deeper understanding of the quantum world, we are beginning to enable the control of quantum systems and the use of their innate properties to our advantage. We now have the possibility to achieve quantum computing, quantum simulation, and quantum cryptography among many other novel technologies. To help drive this innovation, it is imperative to have accurate and reliable theoretical models. One key system of interest is a simple two-level atom interacting with a quantized single-mode cavity. The currently accepted models for this system make approximations that can break down when the atom-cavity coupling becomes sufficiently large. Namely, in the ultrastrong coupling (USC) regime, we can see ambiguous, gauge-dependent predictions. In this thesis, we develop and utilize gauge-invariant master equation techniques to properly simulate this coupled system in arbitrary coupling regimes. We first introduce the necessary theoretical background, followed by an analysis of the effects of the ``gauge-correction'' on the cavity emitted spectra, along with a few other observables of interest in cavity quantum electrodynamics. We then extend our model to include a second atom as a weakly-coupled detector (sensor). Finally, we make this second atom ultrastrongly coupled as well, and analyze the effects of changing the properties of the second atom relative to the first. We see that, in the USC regime, the gauge-correction causes profound and qualitative changes to all the observables studied. These results provide important ramifications for our theoretical understanding of these systems and show that many previously reported results in the USC regime are incorrect and ambiguous, as they do not satisfy gauge invariance.

abstract: M.Sc.


title: Finite Automata with Restricted Nondeterminism and Universality

contributor:
Salomaa, Kai
Computing

subject:
finite automata
nondeterminism
alternation
NFA
DFA
AFA
regular language
state complexity
tree width
path width
ambiguity
universal width
existential width
combined width
width measure
measures of nondeterminism
measures of universality
cycle height
language density
descriptional complexity
alternating

abstract: Deterministic, nondeterministic, and alternating finite automata (DFAs, NFAs, and AFAs) recognize exactly the class of regular languages, and are one of the simplest useful models of computation, having applications in practically all areas of computer science. In general, a DFA can require exponentially more states than an NFA to recognize a language, and an NFA can require exponentially more states than an AFA to recognize a language. Significant work has gone into the descriptional complexity of these models, and in particular, the trade-offs between NFAs with different amounts of limited nondeterminism. Previously studied measures of limited nondeterminism include the ambiguity,  tree width, and path width, which, respectively, measure the number of accepting computations, the total number of computations, and the number of complete computations of an NFA. We present a polynomial algorithm which decides finiteness of an NFA's tree width. We study the growth rates of tree width and path width as functions on the length of the input, paralleling existing results comparing different growth rates for the ambiguity. We show that there exist finite path width NFAs which require exponentially more states to be recognized by a finite tree width NFA, and that there exist AFAs with finite tree width for which any equivalent NFA requires exponentially more states. We introduce the universal width measure, which counts the number of parallel computations followed by an AFA in a single nondeterministically chosen computation. We derive necessary and sufficient conditions for an AFA to have finite maximal universal width, and prove that the finite maximal universal width of an AFA is at most exponentially larger than the number of states. We also introduce the existential width measure, which counts the number of existential branches which do not need to be followed by an AFA in a single computation. We prove that an NFA has finite maximal existential width if and only if it has finite tree width, and that the finite maximal existential width of an NFA is at most polynomially larger than the number of states, even though the finite tree width of an NFA can be exponentially larger.

abstract: PhD


title: Ontario Elementary School Teachers' Approaches to Mathematics Assessment for Diverse Students

contributor:
DeLuca, Christopher
Education

subject:
assessment
classroom assessment
mathematics
diverse students
sociocultural
dialogical self
elementary school teachers

abstract: Classroom assessment has evolved into a dynamic context-dependent social practice, but teachers’ approaches to assessment for diverse students have yet to be adequately explored in the literature. Consequently, the purpose of this qualitative study was to explore Ontario elementary school teachers’ approaches to mathematics assessment regarding the diverse groups of students in their classrooms. Two research questions guided this study: (a) How do approaches to mathematics assessment compare across elementary school teachers? and (b) How do approaches to mathematics assessment within elementary school teachers adapt in response to diverse students? A case study methodology was used, and data sources included interviews, direct observations, survey responses and artifacts. Fourteen teachers participated in the interviews and observations, 69 teachers responded to the survey questions, and 192 artifacts (80 learner profiles, 84 samples of student work, and 28 teacher reflections) were collected. Data analysis was conducted from a joint sociocultural and dialogical perspective and followed the constant comparative method for inductive analysis as outlined in Thomas (2011). Findings suggest that elementary school teachers approach mathematics as a distinctive context for assessment, that their approaches to mathematics assessment are shaped by layers of external influence, and that approaching mathematics assessment in a way that responds to the needs of diverse students is more readily enacted in Kindergarten than in Grades 1-8. Particularly important considerations for approaching mathematics assessment for diverse students are the use of learner profiles, encouraging multiple ways to demonstrate learning, building confidence, redefining success, planning activities that explicitly consider the assessment of diverse students, and maximizing formative assessment opportunities. Key contributions of this research include: (a) providing further depth and complexity around how the contextual factors influencing teachers’ approaches to mathematics assessment interact in the minds of teachers, (b) providing a conceptual model for future research to continue exploring teachers’ approaches to mathematics assessment as a multiplicity of dialogical positions and, (c) providing recommendations for teachers, and a basis for future research, to work towards a more coherent system of assessment by leveraging reflection, consistent terminology, and student engagement.

abstract: PhD


title: Governing Urban Flooding in Global Capitalism: The Relational International Political Economy and Environment of Climate Resilience in Amsterdam, the Netherlands and Dhaka, Bangladesh

contributor:
Soederberg, Susanne
Political Studies

subject: global political economy

subject: international political economy and environment

subject: urban flooding

subject: climate change

subject: global environmental governance

subject: resilience

subject: Amsterdam

subject: Dhaka

subject: Netherlands

subject: Bangladesh

subject: neoliberal urbanism

subject: austerity urbanism

abstract:
This dissertation examines climate resilience policies as a form of flood control in two cities: Amsterdam, the Netherlands and Dhaka, Bangladesh. I situate my examination of resilience within the subnational, national and supranational dynamics of global capitalism and climate change governance that have unfolded since the ascendency of neoliberalism (mid-1970s) until 2020. By undertaking the first transnational study of climate resilience across the traditionally ontologically and epistemologically divided global North and global South, I develop a relational International Political Economy and Environment (IPEE) framework to understand how climate resilience has emerged and is executed as the prominent policy approach to urban flood control in these distinct cities. A relational IPEE approach understands all spaces to be situated in relation to one another in global capitalism, and as such interpretively draws comparisons and contrasts divergences across uneven locales, outlining the relations of power shaping historically and contextually driven everyday experiences. The dissertation format is article-based (otherwise known as the “Manuscript, Project, Portfolio” format), comprised of three independent substantive articles (Chapters Three to Five) that examine the historical, institutional, discursive and material facets of of climate resilience in Amsterdam and Dhaka. These three articles are flanked by introductory (Chapter One), literature review (Chapter Two) and concluding (Chapter Six) chapters. The relational IPEE framework I employ focuses its attention on the role of urban space in global capitalism that comes into tension with comprehensive climate action, and the subnational, national and supranational socio-economic relations of power at play in each of my cases. The two cases selected across the global North and global South divide contextually compare and contrast the patterns and divergences associated with climate resilience on the ground in cities that are disparately framed as “model” masters of water (Amsterdam) and
underdeveloped “apprentices” requiring guidance and change (Dhaka). The content of my dissertation interrupts and interrogates the rhetorical discourse that enhancing resilience can support sustainable forms of urbanization and contributes a theoretically and empirically oriented analysis of the relations of power leading to the reality of uneven socio-spatial experiences with urban flooding across and within Amsterdam and Dhaka.

abstract: PhD


title: Ethics and The Other: An Interpretation of The Philosophy of Emmanuel Levinas

contributor:
Sypnowich, Christine
Philosophy

subject:
Levinas
The Other
Ethics
Intersubjectivity
Wilfred Sellars
Narrative
Paul Ricoeur

abstract: This thesis aims to present a reading of Levinas that defends his philosophy against criticisms that it is ultimately idealistic or quietist, made by thinkers like Gillian Rose and Alain Badiou. This understanding of Levinas is founded on a misreading of his texts, and as such I present a new reading of Levinas work which provides a basis for political thinking. In doing so, I explore the role of the Other in Levinas’ philosophy, and how the Other relates to communities. Using this reading, I show how the objections made to Levinas made by Rose and Badiou do not actually apply to Levinas’ work as he presents it. After this, I present a model of how communities come together on the basis of Levinas work.

abstract: M.A.


title: Networking 2.0: How and Why People Leverage Social Media to Develop Their Professional Networks

contributor:
Spitzmuller, Matthias
Business

subject:
Networking
Social Media
Regulatory Focus Theory
LinkedIn

abstract: Over three quarters of a billion people use LinkedIn around the world, but our understanding of social media platforms like LinkedIn in organizations is that it is a tool used mostly by employees looking to leave of their current positions. Social media, however, are a form of social network and half a century of research on social networks tells us that employees, teams, and organizations can benefit from employees’ personal and professional networks. In this dissertation, I study how and why people develop these networks on social media. I draw on regulatory focus theory (Higgins, 1997) to understand the types of behaviours people exhibit in the service of networking—connecting, relationship maintenance, and self-promotion—and the motives that drive them. Then I integrate social media theory (e.g., Leonardi & Vaast, 2017) and weak tie theory (Granovetter, 1973) to understand how these behaviours shape individuals’ professional networks and ultimately their performance. I test my model across five studies employing both experimental and survey methods. Featuring a randomized experiment, Study 1 examines the degree to which people network differently depending on whether they approach networking with concerns for growth (promotion focus) or security (prevention focus). Studies 2 and 4 examine perceived success or failure as a theoretically relevant moderator of the relationship between regulatory foci and networking behaviours using experimental and survey methods respectively. Study 3 features a multi-sample investigation of the construct validity and factor structure of networking behaviours and Study 5 examines the consequences of networking behaviours for network ties and performance outcomes among undergraduate business students nested in project teams. Although results across these studies show mixed support for the proposed relationships, they provide several important insights about networking in social media contexts and ultimately serve to inform future research on this topic.

abstract: PhD


title:
Synthetic High Resolution Block Model for
Benchmarking Mining Technologies

contributor:
Ortiz Cabrera, Julian Maximiliano
Sari, Yuksel Asli
Mining Engineering

subject:
High-resolution synthetic model
Block model
Benchmarking
Geostatistics
Geostatistical simulation
Geometallurgy
Mine planning

abstract:
Variability of the rock properties and the uncertainty associated with their estimation in the blocks mined and processed becloud the decision making in the mining value chain. In addition to grades of elements and minerals of interest, the presence of deleterious materials, as well as varying geometallurgical properties of rock materials have significant impacts on the economic performance of mining projects. Researchers are faced with the challenge that there are limited opportunities for benchmarking mining methods and technologies as this type of information is proprietary from mining companies and seldom shared for research purposes.

In this thesis, a methodology was developed for building a high-resolution realistic synthetic block model containing grades as well as mineralogical and geological properties for benchmarking purposes. A high-resolution block model, featuring 128 million nodes, was developed for a porphyry copper deposit and used to simulate mining decisions through the mine value chain. To achieve this, samples were extracted from the model by means of a drillhole campaign to allow for comparison of estimation and planning decisions with the actual model data, which provides access to the ground truth. Applications of the developed approach to benchmark advanced mine planning techniques including machine-learning tools in prediction, forecasting, and decision making were also discussed.

abstract: M.A.Sc.


title: Interpersonal Emotion Dynamics in Friendships during Adolescence

contributor:
Hollenstein, Tom
Psychology

subject:
Physiological Synchrony
Socioemotional Flexibility
Psychosocial Adjustment
Stressful Life Events
Social Support
Friend Interactions

abstract: The current dissertation explored interpersonal emotion dynamics in late adolescent female friend dyads, and their associations with psychosocial adjustment (internalizing symptoms and relationship quality), in three empirical studies. In Study 1, physiological synchrony—the moment-to-moment linkage between relationship partners’ physiological responses—during positive and negative contexts was examined as it related to psychosocial adjustment. Friend dyads showed physiological synchrony and dyads differed in their degree of synchrony, but physiological synchrony was not associated with psychosocial adjustment. Study 2 investigated individual differences in socioemotional flexibility—the ability to adjust emotions according to situational demands—across positive and negative emotional contexts. Lower flexibility across contexts was associated with higher internalizing symptoms, and higher overall flexibility was related to higher relationship quality. Finally, Study 3 built on Study 2 and examined potential moderating influences (stressful life events and perceived social support) on the relation between socioemotional flexibility and change in psychosocial adjustment one year later. Higher flexibility and higher exposure to stressful life events or higher social support satisfaction was associated with a decrease in internalizing symptoms over time. Lower social support satisfaction was related to a decrease in relationship quality over time, regardless of level of flexibility. This dissertation contributes to the literature by providing empirical support for describing and characterizing adolescent friendships as temporal interpersonal emotion systems (TIES), where moment-to-moment emotion dynamics and psychosocial adjustment at the developmental time scale mutually influence each other both within and between relationship partners. Findings from this research has implications for understanding the adaptive and maladaptive role that friends may have in shaping socioemotional development.

abstract: PhD


title: Quantifying and Detecting Patterns of Association in Ecological Communities

contributor:
Arnott, Shelley E.
Schamp, Brandon S.
Rusak, James A.
Biology

subject:
community assembly
co-occurrence
species associations
community ecology
null model
scaled co-evenness
sCoE
pairwise associations
type I error
type II error

abstract:
Patterns of non-random species association (co-occurrence), which are common, are frequently used as an indicator of the processes responsible for shaping ecological communities. While a great deal of effort has gone into developing and evaluating the statistical methods used to detect non-random patterns of association, and the metrics used to quantify the patterns, questions remain about their performance. First, there has been no comparison or statistical evaluation of the tests of pairwise association (versus community-level assessments of association). Second, the metrics used to quantify association have not been evaluated independently of statistical tests. And third, evaluations of the community-level null models have focused exclusively on patterns of negative association and on matrices with log-normal species incidence distributions. As a result, it is unclear how well the null models perform when patterns of association are positive or when the underlying incidence distribution is not log-normal.

I conducted three sets of simulation studies to address these three questions, finding that 1) the choice of statistical method, whether pairwise or community-level null model, has a significant impact on the detection of association patterns; 2) the underlying species incidence distribution contributes significantly to the ability of the null models to detect non-random patterns in community-level matrices; and 3) using raw association metrics, and specifically the sCoE metric developed as part of this thesis, provides further insights into community structure allowing for comparisons of association strength over time or between communities.

By addressing these three questions, I not only provide clear guidance for improving the detection of non-random patterns in both community presence-absence matrices and between pairs of species but also provide an intuitive method for evaluating, comparing, and gaining new insights into species associations within ecological communities.

abstract: PhD


title: ‘Jumping-to-conclusions’ about vaccines: An information search perspective on anti-vaccination attitude endorsement

contributor:
Hauser, David J
Psychology

subject:
Vaccine hesitancy
Jumping-to-conclusions cognitive style
Health judgements
Perceiving risk in health

abstract: Vaccine hesitancy has been identified among the top 10 threats to global health (WHO, 2019). Those few who are anti-vaccine have been found to be more likely to believe in conspiracy theories, be high in psychological reactance, express greater disgust toward blood and injections, and hold an individualistic-hierarchical worldview (Hornsey, Harris, & Fielding, 2018). These people will often argue that they oppose vaccines after conducting their own extensive information search, concluding that vaccines are actually unsafe and ineffective. Some will even go so far as to argue that those who get vaccinated are misinformed (Hoffman et. al, 2019). The current research examines whether ‘anti-vaxxers’ are as critical as they claim, or if they actually jump-to-conclusion (JTC). Study 1 (Chapter 2) tests this claim, where the JTC cognitive style – an information gathering bias – is included as a predictor of anti-vaccine attitudes alongside the individual differences mentioned above. Participants completed the JTC probability guessing task, the scales for each of the individual difference measures as well as two subsets of general antivaccine attitudes (e.g., vaccine hesitancy and vaccine skepticism). It was found that those who jumped-to-conclusions (e.g., consulted less information) were more likely to be vaccine hesitant and vaccine skeptical, adding to our understanding of the information search processes that underlie anti-vaccine attitudes. Further, Study 2 (Chapter 3) tested whether a JTC-specific intervention (meta-cognitive training; MCT; Moritz & Woodward, 2007) could be used to reduce a person’s level of vaccine hesitancy and vaccine skepticism, or to promote favourability toward a neutral vaccine-analogue. MCT reduced JTC behaviours but did not reduce global anti-vaccine attitudes. Implications, limitations, and the future directions of these findings are discussed.

abstract: M.Sc.


title: The Enduring Effects of Adolescent Stress on Adult Anxiety-like and Depression-like Behaviours: A Meta-analysis of the Rodent Literature

contributor:
Menard, Janet
Psychology

subject:
meta-analysis
adolescent stress
rodent research
anxiety-like behaviour
depression-like behaviour
social isolation
social defeat
social instability
heterotypic
homotypic
predator exposure
chronic mild stress
chronic variable stress
rat
mice

abstract: In humans, exposure to stressful life events during adolescence is an established risk factor for the development of affective disorders in adulthood. However, the current rodent literature aiming to model this phenomenon has produced inconsistent results. To address this issue, I conducted a series of meta-analyses examining the long-lasting impact of adolescent stress on adult anxiety- and depression-like behaviour in rodents. I conducted a systematic literature search for articles that met my predetermined inclusion and exclusion criteria. Specifically, I included studies that applied stress during adolescence (i.e., postnatal day (PD) 21-60) and reported outcomes from measures of anxiety-like behaviour and depression-like behaviour. A total of 124 studies were eligible for inclusion and standardized mean differences (SMDs) were calculated for each measure of behaviour. I estimated the overall effects of adolescent stress on adult behaviour using a series of random-effects meta-analyses and explored sources of heterogeneity in the data with subgroup analyses according to species, sex, stressor type and age at stress. The results indicated that prior stress increased anxiety-like and depression-like behaviour in rodents. Within species, mice appeared to be more sensitive to the long-lasting effects of stress. There were significant sex differences in the expression of anxiety-like behaviour following stress, but almost identical effects across the sexes in the measures of depression-like behaviour. Heterotypic stress led to the most consistent increases in anxiety-like behaviour and was the only stressor type to increase depression-like behaviour. Finally, the long- lasting effects of adolescent stress appeared to be differentially modulated by the timing of the stress experience. In conclusion, these findings suggest that adolescent stress induces long- lasting changes in affective behaviour. Future research should explore how various factors might modulate the lasting outcomes of stress experienced during this period.

abstract: M.Sc.


title: This is what friendship is to me: A grounded theory of how adolescents with autism spectrum disorder experience and develop friendships

contributor:
Kelley, Elizabeth
Psychology

subject: Autism ASD Adolescent Friendship

abstract: Adolescents with autism spectrum disorder (ASD) experience substantial difficulties developing and navigating social relationships. They are reported to have fewer friends, poorer friendship quality, and increased loneliness in comparison to their neurotypical peers. Despite these social difficulties, youth with ASD report a desire for friendship and they often report experiencing satisfaction in their friendships. There appears to be a mismatch between the empirical literature comparing ASD friendship experiences to neurotypical friendship expectations and the reports of the expressed experiences and desires of youth with ASD. There is a need to better understand the friendship experiences of adolescents with ASD from their own perspective and to integrate these perspectives into the development of theory. In doing so, we may obtain insight into how adolescents with ASD may be better supported in their pursuit of friendship. Using a grounded theory approach, the aim of the current study was to develop, from a psychological perspective, a substantive theory of individual and interactive processes by which adolescents with ASD develop and navigate friendships that are meaningful to them. The grounded theory presented in this dissertation suggests that in developing friendships, adolescents with ASD must traverse the conflict between desiring friendships in which they are accepted for who they are and the struggle to engage in the processes required to establish such friendships due to a range of barriers that promote a tendency to withdraw from and avoid social interaction. This research suggests a core process by which slowly building familiarity with others allows participants to achieve a sense of acceptance within their closest friendships. This research presents a series of sub-processes by which adolescents with ASD interact with their peers to progressively establish more safe and stable meaning in their developing friendships, and by which they subsequently engage in increasingly vulnerable action based on this meaning to support progression of their friendships. Results from this study have implications for the education setting, as well as for clinical intervention, including the targets, modalities and structure of social interventions.

abstract: PhD


title: EXPLORING ELEMENTARY EDUCATORS’ MENTAL HEALTH LITERACY AND DECISION-MAKING USING A MIXED METHOD APPROACH AND ATTRIBUTION THEORY

contributor:
Berg, Derek
Education

subject:
Elementary
Educators
Mental Health Literacy
Mixed Methods
Attribution Theory
Social-Emotional Learning
decision-making

abstract: This study explored a group of Canadian elementary educators’ and their mental health literacy (recognition, help-seeking, attitudes), their social-emotional learning beliefs (comfort, commitment, culture), and their causal attributions and cognitive and affective responses to externalizing and internalizing mental health challenges, to understand decision-making. A mixed method design with two consecutive phases, quantitative (online survey) and qualitative (vignette think-aloud task, semi-structured interview), allowed for an exploration of educators with high and low mental health literacy levels, using descriptive, inferential, and constant comparison analyses. It was found that educators possessed mixed levels of recognition accuracy, and that these were relatively higher than educators’ help-seeking confidence across both phases. In particular, externalizing (i.e., ODD) and internalizing (i.e., OCD) disorders were more recognizable, over specific internalizing ones (i.e., social phobia, depression). High mental health literacy educators expressed higher knowledge of help-seeking strategies, employed tiered-based interventions, and demonstrated higher confidence and self-efficacy in comparison to low mental health literacy educators. Further, educators’ sense of comfort in implementing these was positively associated with their mental health literacy scores. In turn, educators’ personal experience with someone with mental health problems or disorders was found to be correlated with their comfort in implementing social-emotional learning programs. Educators showed that they had sympathetic attitudes towards children with mental health challenges, but they also recollected more incidents that were characterized by student aggression directed both towards students, and towards teachers, themselves. In terms of causal attributions, educators attributed internalizing challenges towards children; in contrast, they attributed externalizing challenges to families. Finally, educators also showed more cognitive and emotional responsiveness towards externalizing behaviours but were more concerned about internalizing challenges. Together, these findings are interpreted to mean that there is an implicit level of bias within educators’ emotions and decision-making about children with mental health challenges. Implications from these findings include increasing support for educators’ mental health literacy in terms of recognition of internalizing challenges, help-seeking knowledge, and providing opportunities for the exploration of emotions and reactions during interactions with children with mental health challenges, especially externalizing ones.

abstract: PhD


title: An Argument-Based Approach to the Validity of Interpretation and Use of Chinese High School Students' Grades across Educational Contexts

contributor:
Cheng, Liying
Education

subject:
validity
grading
grades
admission
Chinese students

abstract:
Driven by the recent trend towards globalization and internationalization, grades are not only used locally where they are constructed, but also internationally for high-stakes admission decision-making into tertiary institutions. This dissertation investigates the validity of the interpretation and use of Chinese high school students’ grades for admission into Canadian universities. Inspired by the argument-based approaches to validity (e.g., Kane, 2006, 2013), the structure of validity argument is adopted as a means to systematically collect evidence, coherently analyze evidence, and present an evaluative judgment.

Theoretically guided by grading frameworks from McMillan (2003) and Kunnath (2017), I propose a validity framework for grade interpretation and use to guide the research design of this dissertation. Three interrelated studies on Chinese high school grades are designed to collect various validity evidence, and these studies are written as individual manuscripts. The first study uses document analysis to explore the embedded values in documents that potentially influence Chinese high school teachers’ grading practices. The second study adopts a questionnaire to examine how local stakeholders, including teachers, students, and parents, interpret and use Chinese high school students’ grades. The third study adopts semi-structured interviews to understand Canadian university admission decision-makers’ interpretation and use of Chinese high school students’ grades.

After a synthesis of the validity evidence collected in the three studies, I believe that overall, the interpretation and use of Chinese high school students’ grades for admission into Canadian universities seems reasonable and appropriate. The conceptualizations of Chinese high school students’ grades by both local stakeholders in China and admission decision-makers in Canada are largely aligned. Admission decision-makers employ various strategies in their use of grades to compensate for the misalignment of interpretation and improve the validity of grade interpretation and use. This dissertation responds to Brookhart’s (2013a) call for theoretically grounded grading research on the meaning and usefulness of grades and extends the validity argument for grade interpretation and use to a cross-cultural level. The research also contributes to the improvement of Chinese high school teachers’ grading practices and helps admission decision-makers in Canadian universities better understand Chinese high school students’ grades.

abstract: PhD


title: Large Scale Physical Modelling of Particle Size Segregation in Granular Flows

contributor:
Take, W. Andy
Civil Engineering

subject:
granular flows
particle size segregation
debris flows
large scale physical modelling
landslide flume
saturated granular flows
multi-component flows
tridisperse material

abstract: Particle size segregation is a phenomenon observed in granular flows of mixed particle sizes resulting in preferential sorting within the flow. In a geohazards context, landslides comprised of a wide range of particle sizes, such as debris flows, therefore exhibit flow structures arising from significant particle size segregation. Size segregation in the vertical direction results in the upwards coarse grading of material, segregation in the longitudinal direction results in the development of a coarse grained flow front, transition zone and fine grained thinning flow tail. Therefore particle size segregation will significantly influence the mobility of the flow, the development of debris fans, and the resulting impact forces to be expected when designing barriers and containment structures to mitigate these geohazards. However, the flow dynamics and depositional processes occurring along the centerline of segregating granular flows is understudied in both dry and saturated flows. Experimental datasets are required to further understanding of the dynamics of segregation and to serve as a basis of comparison to numerical and theoretical model outcomes. Two series of large scale tridisperse granular flow experiments were performed to provide insight on this knowledge gap. The objective of the first test series was to examine particle size segregation observed from a flume sidewall to segregation observed along the centerline of a deposit. A series of replicate tests were conducted to assess different internal transparent plane centerline deposit sampling methods. The results of this testing series demonstrated significant differences between sidewall observations and deposit centerline observations of segregation. The objective of the second test series was to examine particle size segregation differences between dry and saturated flows through comparison of flume experiments conducted with the source volume in a dry or saturated state. For the conditions tested, the travel distance of both flows was sufficient to achieve a mature state of segregation expressed in terms of segregation along the normalized length of the deposit. We anticipate that the dry and saturated large-scale tridisperse flow experimental datasets produced by this work will be used in the calibration of both numerical and theoretical models of particle size segregation.

abstract: M.A.Sc.