title: Autonomous Ground Vehicle Path Following by Combining Feedback Linearization with Model Predictive Control

contributor:
Marshall, Joshua
Mechanical and Materials Engineering

subject:
Model Predictive Control
Feedback Linearization
Optimal Control
Autonomous Ground Vehicle
Path Following

abstract:
This thesis presents the formulation and experimental validation of an autonomous ground vehicle path following control method that combines feedback linearization (FBL) with model predictive control (MPC). The use of MPC for ground vehicle path following tasks has shown to provide high-performance results by leveraging a predictive model to better inform real-time control actions. Traditionally, MPC for ground vehicle path following requires solving computationally expensive nonlinear optimization problems. This increased computational burden can be a significant challenge for real-time implementation. This thesis presents a formulation combining MPC and FBL (MPC+FBL) that is designed to not require the use of expensive nonlinear optimization techniques to solve the MPC optimization. The result is a simple and computationally inexpensive control method that can be used on systems with limited computational resources to achieve near-optimal path following.

This MPC+FBL controller was initially tested in simulation, followed by hardware experiments using a 60 kg skid-steer robot. Hardware experiments were performed indoors and outdoors on various terrains such as plastic floor tiles, grass and sand. The results from these experiments show that the MPC+FBL formulation is capable of near-optimal path following control and achieved more than 30% lower average path following errors in comparison to an implementation of a nonlinear MPC presented in the recent literature. Furthermore, this MPC+FBL formulation can complete controller calculations approximately five times faster than the implemented nonlinear MPC, validating its ability to perform model predictive control with a significantly reduced computational expense.

abstract: M.A.Sc.


title: NLQ INTO SQL TRANSLATION USING COMPUTATIONAL LINGUISTICS

contributor:
Akl, Selim
Computing

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.

subject:
Artificial Intelligence
Structured Query Language
Relational DataBase
Query Language
Natural Language Processing
Machine Learning Algorithm

abstract: This research discusses an automatic translation of an unstructured Natural Language Question (NLQ) into a Structured Query Language (SQL) statement. SQL is used as a Relational DataBase (RDB) interaction language with special query syntax and a computer-executable artificial language. This way, DataBase (DB) administrators or general users with little or no SQL querying abilities can perform queries on RDBs in an interactive manner. The Human-Computer Interaction (HCI) happens using users’ NLQs, which is in English in the proposed research. Users do not need to know any RDB schema elements or structures such as tables’ names, relationships, formats, attributes or data types. The RDB schema is a brief description of the RDB elements’ organization, excluding any RDB values. In this work, a lightweight NLQ into SQL translation approach is implemented by utilizing an RDB MetaTable. The main goal is to exploit a manually written rule-based mapping constraints algorithm. This algorithm maps NLQ tokens’ semantic/syntactic information into RDB elements’ semantic roles (i.e., value, attribute) via pairing and matching means. The matching RDB elements, called “identified lexica”, are then mapped into the SQL clauses consistently for SQL generation and execution. The matching process uses a computational linguistic analysis mapping algorithm, represented in the MetaTables. This mapping algorithm is efficient especially with small RDBs with an accuracy of 95% and is about 93% accurate with larger RDBS.

abstract: PhD


title: Systematic Identification of Interaction Partners of RET Receptor Isoforms

contributor:
Mulligan, Lois
Pathology and Molecular Medicine

subject:
RET
Receptor tyrosine kinase (RTK)
Signaling pathways
SH2 domain
Interactome

abstract:
The REarranged during Transfection (RET) receptor tyrosine kinase is pivotal for normal development of human tissues, but is also an oncogene driver involved in several human cancers.  Alternative splicing at the 3’ end of the RET gene produces two conserved protein isoforms, RET9 and RET51, that differ in their subcellular localization and protein trafficking, and their functional roles in tumorigenesis and metastatic processes, suggesting that they may also differ in their interactomes.
We used a combination of cell-based screening and in silico approaches to identify novel potential interaction partners of RET isoforms. We used a Mammalian Membrane Two-Hybrid (MaMTH) assay using a library of SH2 domain-containing adaptor and signaling proteins, to screen for interactions with each RET isoform. Through different steps of analysis of MaMTH screen data, we narrowed down RET potential interactors.  We complemented these studies by ranking our SH2 prey library using sequence profiles of SH2 domains of known RET interaction partners. Predicted interaction candidates were validated using co-immunoprecipitation assays. A subset of these showed differential interactions with RET isoforms that were mediated through RET isoform-specific docking sites. Our results suggest that combinations of distinct interaction partners may contribute to RET isoform-specific functions.
In this research we developed a systematic approach to map and characterize RET isoform interactions. Our data suggest that no single method identified all known and novel RET interactions, and that a combination of multiple approaches improves characterization of growth factor receptor interactomes.

abstract: M.Sc.


title: Investigating ubiquitin-mediated turnover of the key immune signaling protein kinase BOTRYTIS INDUCED KINASE1

contributor:
Monaghan, Jacqueline
Snedden, Wayne
Biology

subject:
biology
plant immunology
signal transduction
BOTRYTIS INDUCED KINASE1
ubiquitination

abstract: Plants are susceptible to infection from bacterial, fungal, and viral diseases; although sessile, they are far from defenseless. Plants have evolved complex immune systems for the detection of pathogens and initiation of signal transmission to respond to and fight off infections. BOTRYTIS INDUCED KINASE 1 (BIK1) is a key regulator of immune signaling that is required for protection against multiple types of pathogens. BIK1 is activated through phosphorylation by plasma-membrane receptor kinases and, in turn, phosphorylates and activates other downstream proteins. To prevent overactive immune responses, accumulation of BIK1 is tightly regulated through polyubiquitination by PLANT U-BOX 25 and subsequent degradation by the proteasome. My thesis investigates the functional importance of ubiquitination of BIK1 and how this process impacts BIK1 turnover. We identified nine in vivo BIK1 ubiquitination sites using highly-sensitive mass spectrometry. Higher order ubiquitin-ablative mutants were generated to determine which lysine residues are important for proteasomal turnover. Using an in vitro approach, I demonstrate that ablating all nine of these BIK1 ubiquitination sites slows the rate of degradation and therefore that ubiquitination may be important for regulating BIK1 levels in plants. Genetic analyses were explored using site-directed BIK1 mutants in a bik1 knockout or Col-0 background but yielded inconclusive data. This work contributes to the growing body of literature on ubiquitination regulation and highlights that, unlike certain post-translational modifications which are highly residue specific (ie phosphorylation), ubiquitination substrate specificity is likely less critical at the residue level.

abstract: M.Sc.


title: Characterizing the long-lasting impact of stress in mid-adolescence in the rat.

contributor:
Menard, Janet
Psychology

subject:
defensive behaviour
rat
stress
social buffering
resilience
reward
medial prefrontal cortex
hippocampus
basolateral amygdala

abstract: Exposure to stressors in adolescence, in both humans and rodents, leads to long-lasting alterations in their behaviour and corresponding neuroanatomical structures.  The experiments presented herein were designed to further investigate the lasting impact of intermittent physical stress (elevated platform, foot shock, water immersion) in mid-adolescence on adult behaviour and neuroanatomy.  Previously, I demonstrated that exposure to this intermittent physical stress protocol led to differential outcomes if the stressors were experienced during different periods within adolescence (i.e., early vs. mid-adolescence).  The most intriguing outcome from that work was that exposure to intermittent physical stress in mid-adolescence (PD35-46) led to paradoxical increases in exploration of typically avoided areas of the Elevated Plus Maze.  In Chapter 2 of this dissertation, I now demonstrate that this increase in exploration is modified based on the amount of social contact rats experience across adolescence whereby increasing the amount of social contact during adolescence normalized the increases in exploration.  This suggests that affiliative social contact buffers the lasting impact of stress in mid-adolescence and might, in some instances, promote resilience to subsequent stressors in later life. In Chapter 3, I demonstrate that exposure to intermittent physical stress in mid-adolescence not only increases rats’ exploration of open areas of the plus-maze, it also increases their sensitivity to the locomotor enhancing effects of amphetamine, such that their levels of exploration predicted their locomotor response.  Further analysis supported the idea that experiencing intermittent physical stress in mid-adolescence promotes a shift in rats’ behavioural response from a security-centric toward a more reward-centric phenotype. In Chapter 4, I argue that this shift might be due, at least in part, to the stress-induced dendritic remodeling of pyramidal neurons in the anterior basolateral amygdala.  Collectively, these findings suggest that exposure to stressors, when restricted to mid-adolescence, promotes neuroanatomical and behavioural changes that facilitate risk-taking phenotypes.

abstract: PhD


title: Observation Points based Multi-modal Fusion Systems for Skeleton Action Recognition

contributor:
Greenspan, Michael
Zhu, Xiaodan
Electrical and Computer Engineering

subject: Skeleton Action Recognition

abstract: Current methods for skeleton-based action recognition compute features based on the given skeleton joint information. We show that introducing new observation points in skeleton motion sequences and using them to create fused representations from multiple modalities such as joints and bones, can enhance the discriminative power of the original modalities. Moreover, such representations can be used to create new streams in multi-stream networks that fuse constructively with other streams trained on the original modalities, effectively exhibiting a dual behaviour and collectively boosting the performance of the network even further. In this work, we present certain configurations of multi-modal fusion systems with observation points that can easily be incorporated in existing networks and improve state-of-the-art results on the two popular J-HMDB and Kinetics-Skeleton action recognition datasets.

abstract: M.A.Sc.


title: Co-occurring Posttraumatic Stress Disorder Symptoms and Dementia in Veterans Living in Long-Term Care

contributor:
Cramm, Heidi
Aiken, Alice
Rehabilitation Science

subject: PTSD Dementia Veterans

abstract:
Background: In older Veterans with dementia, Posttraumatic Stress Disorder (PTSD) can emerge, re-emerge, or worsen, resulting in negative consequences for Veterans and their families. Once admitted to long-term care (LTC), health care providers can misattribute symptoms associated with the co-occurrence of PTSD and dementia to the behavioural and psychological symptoms of dementia, and this can result in inappropriate interventions. The purpose of this research is to explore how the co-occurrence of PTSD symptoms and dementia is understood and identified in Veterans living in LTC.
Methods: This dissertation consisted of three studies. The first study was a scoping review that examined how the relationship between PTSD and dementia in Veterans has been described in the literature. In study two, multiple case studies were conducted to understand co-occurring PTSD symptoms and dementia in Veterans in two LTC facilities in Canada. The third study used a qualitative descriptive approach to explore how health care providers in Canada have learned to identify co-occurring PTSD symptoms and dementia in Veterans.
Results: PTSD and dementia in Veterans is an emerging area of research that is focused on understanding the etiology underlying the relationship, the symptomatic expression of PTSD and dementia, and the implications on health care providers, treatment, and resources. Case studies revealed that co-occurring PTSD symptoms and dementia are recognized as different than dementia alone, but these differences are highly nuanced and result in greater care challenges. Effective interventions are tailored to address specific symptoms. Moreover, health care providers recognize differences in co-occurring PTSD
iii
symptoms and dementia from dementia alone and tailor their care approach to specific symptoms, instead of using usual care strategies for dementia.
Conclusion: The results of this dissertation contribute foundational information about co-occurring PTSD and dementia symptoms, highlight important identification issues, inform potential interventions and educational needs of health care providers, and inform future research to enhance the identification of co-occurring PTSD symptoms and dementia in Veterans.

abstract: PhD


title: Caching in VANETs for Social Networking

contributor:
Hassanein, Hossam
Abdelhamid, Sherin
Computing

subject:
VANETs
Proactive Caching
Cooperative Caching
Social Media
Edge Caching
5G

abstract:
Social media traffic constitutes the highest percentage of Internet traffic. This social media traffic is largely facilitated by mobile devices, which imposes a huge traffic load on backhaul links in 5G networks, and can in turn affect the quality of service. This traffic load can be alleviated by using vehicular networks as a traffic offloading platform. In particular, vehicles can act as a resourceful asset for edge caching, which enables data acquisition from nearby caching nodes rather than the remote backhaul servers. However, caching in vehicular networks encounters many challenging issues. This includes the highly dynamic nature of vehicles, which can lead to instability in caching decisions. Also, despite being equipped with storage resources, relying on static roadside units for caching might not always be feasible. This is due to the large investments that their wide deployment requires. Another challenge is prompted by the high delay and low packet delivery ratio often associated with accessing data from distant content providers in vehicular networks, which makes it imperative to take the quality of service into consideration during caching.

In this thesis, we propose a caching framework that aims at maximizing cache hit ratio, as well as improving the quality of VANET-based Internet services. To do so, we consider two types of users; users who exhibit a predictable behavior resulting from their daily routine during driving from one place to another, and those who do not have such a routine. We exploit the predictable behavior of the  first type of users in order to pre-cache the data at roadside parked vehicles for requesters to proactively acquire as they pass by. In order to promote informed proactive cache placement decisions that consider the spatiotemporal availability of replicas, we propose a travel time prediction scheme to be incorporated into the caching
process.

For the second type of users, we use the static and mobile nature of parked and moving vehicles, respectively, to leverage the use of cooperative caching within the context of VANETs. This solution involves a content discovery module and a cache placement module. The former enables the nodes to dynamically locate replicas that are close to the requester during the request-forwarding process. The latter facilitates making informed caching decisions to decide where and what to cache.
This is done while extending the search space and the cooperation range beyond the neighborhood scope in order to increase cache hits. We also cope with the dynamic nature of vehicles by proposing a vehicles' trajectory prediction scheme. Extensive simulations demonstrate the ability of the proposed approaches to achieve significant improvements
in their targeted objectives compared to other prominent caching and prediction schemes in VANETs.

abstract: PhD


title: CONTINUITIES AND CHANGES IN TRADITIONAL AKAN ENVIRONMENTAL PRESERVATION PRACTICES

contributor:
Weldemichael, Awet
Cultural Studies

subject:
Environment
Religio-cultural beliefs/practices,
Human-environment relation theory
Indigenous Religion
Culture
Kwahu Traditional People

abstract:
This dissertation examines traditional religio-cultural beliefs/practices and environmental
problems in Ghana using the Kwahu Traditional Area as a case study. Its primary objective is to
examine the continuities and changes in the traditional Akan environmental preservation practices.
It explores how these practices have evolved in pre-colonial, colonial, and post-colonial periods.
It also delves into whether the original intention for instituting the Kwahu peoples' religio-cultural
beliefs and practices was to tackle environmental problems or whether its establishment was for
other purposes but is unconsciously serving the former. Moreover, the study investigates whether
the traditional Kwahu environmental beliefs and practices are old practices with old environmental
awareness, which has been retooled to tackle contemporary environmental issues. The study
employs qualitative data from 89 (23 females and 66 males) in-depth interviews conducted in 16
communities across the Kwahu Traditional Area of Ghana between June–November 2017 and
June–July 2018. I supplemented the interviews with observations. The research has been carried
out within the framework of the human-environment relationship theory. Overall, this study
reveals that both external and internal factors—the impacts of colonialism, the rising interference
of central government in local affairs without regard for local initiatives and sovereignty, and the
inroads made by Christianity—have influenced that changes in the traditional environmental
preservation practices of the Kwahu people. The findings also suggest that changes in traditional
environmental practices have both favourable and adverse impacts on the natural environment.
Further, the findings disclose that traditional environmental practices that solely rely on
supernatural justification to achieve compliance have been undermined because of the erosion of
the reverence attached to traditional representative. However, resource management practices that
have utilitarian relevance, in addition to their metaphysical values, are still observed in
contemporary Kwahu societies. The findings imply that despite the changes in traditional
environmental practices, they are still relevant in addressing environmental issues in the study
area. This dissertation suggests that a collaboration between the Kwahu people's traditional
approaches to environmental conservation and alternative approaches to environmental
conservation, namely modern (scientific) methods becomes all the more important.

abstract: PhD


title: DEVELOPMENT OF CORE-SHELL METALLIC NANOPARTICLES FOR OPTO-ELECTRONICS

contributor:
Nunzi, Jean-Michel
Chemistry

subject:
Plasmonics
Ag NPs
HfO2 NPs
Au@HfO2 NPs
Au@HfO2@dye-SiO2
Metal-enhanced fluorescence
Core@Shell NPs
Dye-doped silica NPs
Characterization techniques for NPs

abstract:
The engineering and design of metal nanoparticles (MNPs) that possess unique size-dependent optical and electronic properties is a promising area of research. The aim of this thesis is to design and to prepare uniformly sized NPs which bear a dielectric shell that can exhibit desirable properties that can be utilized in solar cells and organic light emitting diodes.
This dissertation is structured in five main chapters. First, a literature review focuses on theories and synthetic approaches that are relevant to the objectives of the study. In chapter 2, Ag NPs were prepared via the seed-mediated growth method. The effect of the pH on the yield was explored to increase the monodispersed yields of Ag NPs with various diameters. The plasmonic effect of Ag NPs diameters on inverted organic solar cell performance was explored. This study shows that the diameters of NPs can be controlled by altering the pH values. The performance of the subjected device increases with an increasing Ag NP diameter, yet the 70 nm Ag NPs yielded weaker performance. Chapter 3, Au NPs were synthesized via a high-temperature reduction method in an organic medium. This research study is the first attempt to coat Au NPs with HfO2 shell at two different shell thicknesses. The plasmonic peak shifted to longer wavelength according to the refractive index of HfO2. Additionally, the adverse effects of high-speed centrifugation on the stability and optical properties of NPs were studied. Chapter 4, HfO2@dye-SiO2 and Au@HfO2@dye-SiO2 MEF NPs were
iii
successfully obtained. Oregon Green-488 maleimide dye was functionalized and embedded in the SiO2 matrices. The emission enhancement and increasing in the Stokes shift of functionalized dye could ensure its suitability for laser-based applications. In conclusion, the design and tuning of the NPs will provide highly desirable NPs at high yields that would be suitable for use in electronic and optical devices at industrial scales. Also, some suggestions were proposed for future investigations that could provide improved results.
Lasty, throughout my Ph.D's journey, my curiosity drove me to focus on NP synthesis. Therefore, the Appendix provides data obtained from the synthesis of NPs with different sizes and shapes.

abstract: PhD


title: Techniques for Enabling High-Order Modulation Formats in Short-Reach Optical Communication Networks Based on Directly Modulated Lasers

contributor:
Cartledge, John
Electrical and Computer Engineering

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Directly modulated laser
DML
FDM
Fiber optics
Kramers Kronig receiver
Optical communications
Optical networks
Power loading
SCM
Short reach

abstract:
The need to satisfy bandwidth-hungry applications with a growing number of internet users has raised the requirements for capacity and reach in optical communication systems. Recent advances in field modulation and digital coherent detection enabled applications in long- and medium-reach systems. For short-reach systems, such as intra- and inter-data center connections, solutions which consider their sensitivity to both cost and system complexity are required. Systems based on intensity modulation and direct detection (IM/DD) are good candidates to fulfill the requirements of many short-reach applications. In an IM/DD channel, chromatic dispersion and the dispersion-induced frequency-selective power fading are major issues which limit the system performance. The primary objective of this research is to enhance the transmission performance in IM/DD systems, with a focus on using a transmitter based on a directly-modulated laser (DML). The capacity and reach of an IM/DD system are improved by employing higher-order modulation formats and mitigating chromatic dispersion and the resulting frequency-selective power fading.
For this purpose, two main approaches are investigated by simulation. In both approaches, higher-order modulation formats are enabled by employing subcarrier modulation (SCM) with a transmitter based on the direct modulation of a 10 Gb/s commercial packaged laser. For modeling the laser, a rate-equations model is adopted. The values of the rate equations parameters and the elements in an equivalent circuit model for the electrical interface are extracted based on a series of measurements using a comprehensive procedure.
In the first approach, several radio frequency (RF) channels using the same modulation format are multiplexed before driving the DML. The frequency-selective power fading is mitigated by optimizing the modulation conditions of the DML and employing power loading of the RF channels. Using a practical two-tone test and the received signal-to-noise-and-distortion ratios, an iterative procedure is presented to calculate the required power loading which equalizes the performance of the channels. In the second approach, vestigial sideband transmission is employed to mitigate the frequency-selective power fading of the channel. The use of the Kramers-Kronig (KK) receiver with a DML is validated, and the KK receiver is utilized to enhance the system performance with the compensation of chromatic dispersion in single-channel transmission.

abstract: PhD


title: TECHNOLOGIES TO IMPROVE GAN-BASED LLC RESONANT CONVERTER FOR WIDE INPUT VOLTAGE, HIGH OUTPUT CURRENT AC-DC AND DC-DC APPLICATIONS

contributor:
Liu, Yan-Fei
Sen, Paresh C.
Electrical and Computer Engineering

subject:
GaN
LLC resonant converter

abstract:
The industry driving toward smaller, and more efficient electronics has led to the development of Switch Mode Power Supply (SMPS) in today’s most popular industrial applications. Resonant converters, among a variety of mainstream power converter topologies, are receiving more and more attention owing to their features of high efficiency and high power density.
This thesis discusses several challenges to apply LLC resonant converter in industrial applications, including wide input voltage range, poor feedback performance, output current unbalance among multiply phases, and double line frequency ripple with power factor correction (PFC). Aiming at these issues, several solutions have been proposed.
A single-stage LLC converter is used in power adapter applications. Voltage doubler circuit is added to reduce the rectified DC bus voltage range. Thus, the LLC converter can be designed with narrow input voltage range, and large magnetizing inductor can be used, which reduces the rms current and the turn-off current.
A frequency modulation with nonlinear voltage-controlled-oscillator (VCO) is proposed to improve the feedback performance of LCLC converter in data center applications. Conventional linear VCO may cause oscillation at low inputs or poor dynamic response at high inputs. However, the proposed nonlinear VCO could achieve better feedback performance.
A three-phase interleaved LLC converter is proposed for high output current EV low voltage DC-DC charger (LDC) applications. With proposed three-phase interleaved topology, the conduction loss and copper loss can be reduced significantly. In addition, the switches current rating is reduced.
Due to the resonant component tolerance, severe current unbalance happens in three-phase interleaved LLC converter. To achieve current sharing, full-wave switch-controlled capacitor (SCC) circuit is added into the resonant tank to compensate the tolerance. In addition, a digital comparison control strategy is proposed to control the SCC switches for current sharing.
A single-stage LLC converter with PFC is applied in EV AC-DC on-board charger (OBC) application. A power converter-controlled capacitor (PCCC) is proposed to eliminate the double line frequency voltage ripple on LLC PFC converter output side. The average power handled by the PCCC is zero.
In this thesis, the proposed theories are verified by mathematical analysis, computer simulation and experimental testing.

abstract: PhD


title: USING BIOGEOCEMENTATION TO REDUCE PHYSICAL INSTABILITY AND WIND EROSION OF MINE TAILINGS

contributor:
Champagne, Pascale
Civil Engineering

subject: Sporosarcina pasteurii

subject: Liquefaction

subject: Microbially induced calcite precipitation

subject: Mine tailings

subject: Dust suppression

abstract:
The mining industry in Canada is an essential driver of economic growth as societal demands for minerals increases with advances in technology. The waste generated through these mine operations is one of the biggest environmental and safety hazards in the world, with the long-term storage of this waste in tailings dams being a geotechnical and geochemical hazard.
The biogeocementation of tailings, using calcite produced by microorganisms to create rock-like tailings deposits, is an attractive concept because a bio-cement can be formed that is durable enough to improve the mechanical behavior of the tailings. In this work, the microorganism Sporosarcina pasteurii was explored for its effectiveness at performing biogeocementation to physically stabilize gold and nickel mine tailings and prevent the wind erosion of gold mine tailings deposits. S. pasteurii was proven to be resilient when exposed to heavy metals at low concentrations, from temperatures of 4 to 31C, and pH values from 2 to 12, indicating S. pasteurii can survive in the potentially harsh conditions of tailings dams. S. pasteurii was then utilized to strengthen undrained gold and nickel tailings. Gold tailings from the Dominican Republic showed a 6.8% increase in shear strength with bacteria inoculation whereas nickel tailings from British Columbia showed an 18% decrease in shear strength. This indicates biogeocementation was successful for the gold tailings and unsuccessful for the nickel tailings which could be due to pore clogging. Finally, S. pasteurii was investigated for its ability to withstand wind speeds up to 15 km/h with the average percent mass lost reduced to 0.46  0.22% from 3.99  0.88%. The most effective application method for biogeocementation was found to be a single application of S. pasteurii followed by a continuous application of nutrient amendments, which has positive implications for field level scale-up. The promise of biogeocementation is demonstrated in this thesis, however, future proof-of-concept work needs to be performed to further characterize the robustness of S. pasteurii and determine its effectiveness in real-world environments, such as tailings dams.

abstract: M.A.Sc.


title: Childhood Maltreatment and the Association with Life Dissatisfaction

contributor:
Stuart, Heather
Public Health Sciences

subject:
maltreatment
child maltreatment
life satisfaction
child abuse
long term effects
life dissatisfaction
adult life satisfaction
early childhood experiences

abstract:
This study examined the association between childhood maltreatment (witnessing violence in the household, and experiences of physical and emotional abuse by an adult prior to the age of 16,) and dissatisfaction with later life. Experiences in childhood have been shown to have influences on the developing child (both on the brain and body), with adverse experiences associated with increased risks for negative life outcomes (such as mental and physical illnesses). Dissatisfaction with life has also been shown to lead to negative health outcomes; therefore, the goal of this research was to determine if childhood maltreatment could predict life satisfaction/dissatisfaction.
As a secondary analysis, this study used data from more than twenty-five thousand individuals aged 15 and over who participated in the Canadian Community Health Survey-Mental Health (2012). The data were analyzed using bivariate and multivariate logistic regressions. Two regression models were developed. Model 1 utilized a cumulative count variable representing ‘Number of Types of Childhood Maltreatment Experienced’ as the exposure variable, and model 2 utilized a binary exposure variable representing ‘Ever Abused’ as the exposure variable. Life dissatisfaction was measured using the survey item, “Using a scale of 0 to 10 where 0 means ‘Very dissatisfied’ and 10 means ‘Very satisfied’, how do you feel about your life as a whole right now?”, where scores of 0 to 4 represented dissatisfaction.
Compared to individuals who did not experience maltreatment in childhood, experiencing four types was significantly associated with more than twice the odds of dissatisfaction with life (AOR= 2.356; CI 1.595- 3.481), and experiencing any maltreatment in childhood increased ones odds of later life dissatisfaction by 40% (AOR= 1.424; CI 1.119- 1.813). Both models controlled for: total household income, self-perceived physical health, self-perceived mental health, and measures of emotional and social support (has people to depend on, and has close relationships). The following variables were adjusted for, but determined statistically insignificant: age, importance of religion, family mental health, and education. The findings from this study suggest childhood maltreatment predicts life satisfaction in later life, prompting further research into preventing and mitigating the effects of child maltreatment.

abstract: M.Sc.


title: Spatial Voting Models: A Dynamical Systems Approach

contributor:
Taylor, Peter
Mathematics and Statistics

subject:
spatial voting models
dynamical systems
game theory

abstract: Spatial voting models have been used extensively to study factors affecting candidate positioning in elections. Most previous research has fixed candidate positioning at one point in time to determine optimal candidate payoff.  In this paper we examined candidate positioning within a dynamical system, thereby adding a temporal component to the analysis that allowed for a more realistic model of candidate behaviour in the lead-up to an election. Using a two-candidate and one-voting bloc case, the results from this research identified several critical points that described different types of candidate equilibria. Competitive critical points mirrored findings in previous research. Flip-Flop and Noncompetitive points, however, identified sub-optimal candidate positions that might arise during an election. Flip-flop points appeared to highlight situations in which candidates oscillated between trying to outmaneuver their opponent and attempting to move closer to their ideological positions. Noncompetitive points seemed to describe candidate intransigence regarding their policies. Bifurcation analysis revealed how the dynamical system was affected by subtle differences in the voting bloc’s position. We also examined the relationship between the Nash equilibrium solution concept and asymptotic stability of critical points. Although our findings suggested that Nash equilibrium points are always asymptotically stable critical points, the converse was not necessarily true. Future studies might extend this spatial voting model by increasing the number of candidates or weighting the voting blocs to see how these changes affect the dynamics. Additional research could also investigate whether it is true that an asymptotically stable critical point with complex eigenvalues is never a Nash equilibrium point in all dynamical systems.

abstract: M.Sc.


title: Stray Gas Migration: Multicomponent Mass Transfer Effects on Dissolution and Persistence of Gas in the Subsurface

contributor:
Mumford, Kevin
Civil Engineering

subject:
Stray gas
Gas migration
Multicomponent
Mass Transfer
Gas Persistence
Gas fate
Hydrocarbon leak
Fracking
Shale gas
Trapped gas
Natural gas
Gas ratio
Dissolved gas ratio
Multicomponent effects
Hydrogeology
Gas dynamics

abstract:
As the development of deep geological gas reserves increases in the coming years, concern has been raised regarding potential environmental impacts including stray gas migration. The goal of this research was to improve investigation techniques at suspected stray gas migration sites by studying multicomponent mass transfer effects on the dissolution and persistence of trapped gas in the subsurface, and potential changes to one of the principal source identification tools, hydrocarbon ratios, over time. This goal was achieved by conducting small-scale (5.3 cm length, 7.2 cm diameter) column experiments, in which single- and multicomponent natural gas mixtures were trapped in sand. Water was pumped through the column, and dissolved gas concentrations were monitored over time. The experiments were simulated using a reactive transport code, MIN3P. Further simulations were conducted to investigate the effects of background dissolved gases on the persistence of gas in the subsurface, and potential changes in hydrocarbon ratios due to multicomponent mass transfer. Additionally, a set of calculations were conducted to determine potential errors for hydrocarbon (and other dissolved gas) ratios due to the misinterpretation of analytical results, and how the use of hydrocarbon ratios may be impacted in practice.
MIN3P was successfully used to simulate the dissolution of both single- and multicomponent source trapped gases in porous media. Laboratory and numerical simulations showed that the aqueous concentrations during gas dissolution are generally insensitive to dissolved background gas concentration, but that gas persistence is highly sensitive to background gases. Multicomponent mass transfer can lead to variation in hydrocarbon ratios over time due to differences in gas partitioning properties, and as such they should be coupled with other identification methods. Furthermore, hydrocarbon ratios should be calculated using an equivalent gas pressure when interpreting dissolved gas concentrations, as other interpretations can lead to significant error (a factor of 1.15 to 2.67 under the conditions considered in this study). The findings of this research demonstrate that it is important to consider multicomponent effects in stray gas migration, as the presence of multiple components in both the source and the background has substantial impact on the dissolution of gas in the subsurface.

abstract: M.A.Sc.


title: Security of Short-Range Wireless Technologies and an Authentication Protocol for IoT

contributor:
Zulkernine, Mohammad
Computing

subject:
IoT
Security
Wi-Fi
Bluetooth
ZigBee
Attack-Defense Trees
Physical Unclonable Functions
Authentication
IoT attacks

abstract:
The number of wireless IoT (Internet of Thing) infrastructures is considerably growing as thousands of new devices are being connected everyday. This has allowed the emergence of various smart applications that have changed the lifestyle of many people. However, as security has always been an afterthought to innovation, the security of these infrastructures
has raised serious concerns. The research community has to conduct serious investigations before IoT grows further and it becomes too late. Thus, we devote this Ph.D. thesis to study and improve the security of IoT wireless infrastructures, in particular, those adopting Wi-Fi, Bluetooth, ZigBee, and RFID technologies. To that end, we divide this thesis into two parts.
In Part 1, we review the technologies and propose an attack taxonomy to classify existing attacks on these technologies and discuss possible countermeasures. Moreover, we analyze the security of these technologies and identify new vulnerabilities and attacks. In Part 2, we analyze the security of recent PUF (Physical Unclonable Function)-based authentication protocols and propose a generic authentication protocol for IoT. We specifically design the protocol for wireless Thing-to-Thing communication scheme. We implement the protocol on resource-constrained devices and perform security as well as performance analysis. We show that the proposed protocol is secure and efficient in terms of execution time, communication overhead, and energy consumption.

abstract: PhD


title: Beta-Band EEG Activity and False-Belief Reasoning in Adults

contributor:
Sabbagh, Mark
Psychology

subject:
Theory of Mind
EEG
False Belief
Beta

abstract:
The ability to reason about other’s beliefs, and in particular their false beliefs, is a fundamental part of having a theory of mind (ToM) – an understanding of the role that mental states (i.e., beliefs, desires, and intentions) play in causing behavior. Reasoning about others’ minds is difficult, particularly when others’ perspectives are different from one’s own, as is the case with false beliefs. One explanation for this phenomenon may be the anchoring-and adjustment theory, which stipulates that our first guess about other’s mental states is “anchored” to our own perspective (that is, we think that they think what we do) and then adjusted, based on what we know about the other person and their contextual circumstances. If this theory is correct, then neurocognitive processes associated with flexible thinking should be implicated when reasoning about others’ false beliefs. To investigate this possibility, the relationship between beta electroencephalographic (EEG) oscillatory activity and belief-reasoning was examined in
adults. The suppression of beta EEG activity has been associated with processes such as cognitive flexibility, learning, and dopaminergic functioning; therefore, it may also be involved in the adjustment process. In this study, 39 adult participants were recruited, and EEG recordings were obtained in response to a series of false-belief and true-belief tasks. It was hypothesized that: 1) beta EEG activity will be suppressed more when reasoning about others’ false beliefs relative to their true beliefs, and that 2) beta suppression will be evident at scalp sites that are typically associated with neural regions that are important for ToM reasoning, including the dorsomedial prefrontal cortex (dmPFC) and the right temporo-parietal junction (rTPJ). Results showed significant trial effects for beta suppression at the dmPFC, but not the rTPJ. These results demonstrate that beta EEG activity may be used as an index for belief-reasoning and, in turn, may reflect aspects of the neurocognitive factors underlying the anchoring-and-adjustment process.

abstract: M.Sc.


title: Interweaving Iiyiyiu (Cree) Ways of Knowing and Land-Based Learning with Science Curriculum at Waapinichikush Elementary School, Chisasibi, Quebec

contributor:
Davis, Jennifer
Christou, Theodore
Education

subject:
Indigenous education
Indigenous science
Land-based learning
Decolonizing education

abstract:
This study is the result of work done in close collaboration and partnership with local Cree (Iiyiyiu) teachers, Elders and community members at Waapinichikush Elementary School in Chisasibi, Quebec, to identify approaches to learning and teaching science that are culturally appropriate and to bring student learning outdoors and onto the land. A participatory action research approach incorporating Indigenous research methods was used. Teachers, Elders and other community members worked collaboratively in developing land-based science learning opportunities. Qualitative observations were then used to determine if students were more engaged in land-based learning, had a greater sense of cultural identity, and achieved greater academic success including an increased use of the of Cree language (Iiyiyiuyimuwin) with these methods of teaching.
	The aim of this research is to work towards a decolonized approach to teaching and learning by building bridges between Western and Iiyiyiu approaches to education and especially, to prioritize and emphasize Iiyiyiu ways of knowing in leading land-based initiatives at Waapinichikush Elementary School. This project also identified several practical ways for non-Indigenous teachers to respectfully adapt their lessons to seasonal themes based on Cree (Iiyiyiu) perspectives and land-based learning. By prioritizing Iiyiyiu ways of knowing and land-based approaches to learning, it is hoped that a more decolonized vision of education will emerge especially in the teaching of science. Students who participated in outdoor learning opportunities were observed to be highly engaged and enthusiastic and showed increased knowledge of Cree vocabulary. Students were also more focussed on academic tasks when we returned to the classroom after participating in land-based activities. Community and parental involvement gradually increased as this study progressed, and positive involvement and interest emerged. Finding a balance between teaching the Western standards of education, especially in the teaching of classroom science and the cultural knowledge and teachings from the land remains an ongoing challenge. However, this study demonstrated the interest, capacity and expertise that exists in the community and shows great promise for the development of future initiatives at the school which could build upon the resources and expertise identified.

abstract: M.Ed.


title: ANALYSIS, OPTIMIZATION, AND PRACTICAL DESIGN OF A SPLIT-PHASE DICKSON SWITCHED CAPACITOR CONVERTER FOR HIGH CURRENT APPLICATIONS

contributor:
Liu, Yan-Fei
Electrical and Computer Engineering

subject: Power Electronics, Switched-Capacitor Converter, Dickson Converter

abstract:
The Switched-Capacitor Converter (SCC) topology has been gaining attention from researchers because of their advantages of higher power density, better switch utilization, and low component stress. However, SCCs have a fundamental downside in which capacitor charge redistribution causes significant current spikes. This can be solved using as split-phase control, which addresses charge redistribution in the Dickson SCC by controlling the charging and discharging of the flying capacitors, such that the equivalent branch voltages line up when switching occurs.
In adapting the split-phase Dickson SCC topology for high-current applications, two significant sensitivities of split-phase control were identified. Differences between the actual values of the flying capacitors results in split-phase control not fully compensating for charge redistribution, due to the capacitors’ uneven charge and discharge rates. Furthermore, input voltage ripple tends to cascade into the circuit, leading to voltage imbalance within the circuit.
To minimize capacitor mismatch and factoring in the problem of ceramic capacitor de-rating, the flying capacitors of the split-phase Dickson SCC were designed by referring to capacitor de-rating curves supplied by component suppliers. However, potential inaccuracies in the curves, combined with typical manufacturing tolerances of ±20%, led to the development of an in-circuit flying capacitor measurement method to allow for possible tuning of the flying capacitors.
The sensitivity of the Dickson SCC to input voltage ripple was initially bypassed by using a very large input capacitor to suppress input voltage ripple. However, this resulted in additional losses due to the equivalent resistance of the electrolytic capacitor that was used. As such, an input voltage compensation method, which adjusts the duty cycles of the ‘split-phase’ switches to compensate for the additional voltage difference resulting from input voltage ripple interference, was developed.
The research presented in this thesis provides in-depth analyses of both sensitivities of the split-phase Dickson converter, as well as a discussion on their impacts on the design of components for the high-current split-phase Dickson SCC. Test results of a 48 V to 12 V, 35 A split-phase Dickson SCC prototype are also presented and discussed.

abstract: M.A.Sc.


title: What Is Known About the Atlantomastoid Muscle: A Scoping Review

rights: Attribution-NonCommercial-ShareAlike 3.0 United States

subject:
atlantomastoid muscle
scoping review
literature review
anatomy
anatomical variation
muscle variant


title: Disturbing Silence: How the Student Movement Shaped Nixon’s Presidency and the Policies of America

contributor:
Currarino, Rosanne
History

subject:
Vietnam War
Foreign Policy
Students for a Democratic Society
Nixon
Kissinger
Social Movements
FBI
Counterintelligence Program
Policing
Cold War

abstract: President Richard M. Nixon’s fear and hatred of the Students for a Democratic Society (SDS) resulted in the SDS having an undue influence on his foreign policies. The SDS was a small faction of the larger Anti-Vietnam War movement. Despite that, by 1969, Nixon’s fixation on the movement affected Nixon’s policies surrounding the secret negotiations between National Security Advisor Henry Kissinger and the North Vietnamese. Nixon felt it necessary to maintain the perception of an American united front to the Vietnamese. Accordingly, Nixon felt it was imperative to silence the very vocal and visible SDS by any means necessary. His fear of the group led to changes in his domestic policies including the escalation of harsh FBI surveillance on American citizens and an adjusted draft lottery. This same fear translated in foreign policy shifts including his new policy of Détente. It was indeed the President’s fear of a small social movement which changed major governmental actions and goals.

abstract: M.A.


title: INVESTIGATION INTO POTENTIAL MAGMATIC CONTRIBUTIONS TO VOLCANOGENIC MASSIVE SULFIDE DEPOSITS: METHOD DEVELOPMENT FOR LA-ICP-MS ANALYSIS OF FLUID INCLUSIONS AND CRITICAL ASSESMENT OF THE WINDY CRAGGY DEPOSIT, NORTHWESTERN BRITISH COLUMBIA, CANADA

contributor: Geological Sciences and Geological Engineering

subject:
Fluid inclusion
Windy Craggy
VMS
Laser ablation

abstract: In recent years, the existence of variable magmatic contributions to the mineralizing fluids in the formation of volcanogenic massive sulfide (VMS) deposits has been gaining acceptance in the scientific community. The world-class Windy Craggy Cu-Co-Au deposit (>300 MT @ 2.12 wt.% Cu) located in northwestern British Columbia is the ideal location to investigate this potential for multiple reasons: 1) a previously completed study documented fluid inclusions with anomalously high salinities relative to other VMS deposits; 2) Windy Craggy has an atypically large size and Cu grade compared to other VMS deposits. In this study a method was developed using an excimer (193 nm) laser ablation system interfaced to a quadrupole inductively coupled plasma mass spectrometer, which proved effective in quantifying key metals and metalloids in the inclusion fluids considered by many to be indicative of magmatic contributions to hydrothermal ore deposits. Despite the highly transient nature of the signal from the low salinity (most 6 – 16 wt.% eq. NaCl) inclusions, , of the total 34 elements that were monitored, Na, Mg, K, Ca, Mn, Fe, Co, Cu, Zn, Sr, Sn, Ba, Ce, Pb and Bi were consistently detected and quantified. Furthermore, Cl, Sb, Cd, Mo, Rb, Br, and As were also detected in a significant number of inclusions. Positive correlations between Cu, Mn, Zn, Sb, Sn and Bi were observed. The Ca/Na values in the fluid inclusions are greater than seawater and generally similar to values reported from other maficdominated VMS systems. The host lithologies and mineralization (footwall argillite, relatively fresh to highly altered footwall mafic volcanic rocks and stringer and massive sulfide) from Windy Craggy were also bulk geochemically analysed. The fluid inclusions show similar trends and overlap the host rocks in Fe vs Mn and Cu vs Zn, but show clear excesses over the host rocks, and in particular the sulfide-rich samples, in Sb, Sn and Bi that are commonly ascribed as indicative of magmatic contributions in other deposit types. These excess values strongly indicate a direct magmatic contribution to the Windy Craggy ore-forming fluids, as opposed to simply reflecting leaching of metals from the footwall sedimentary and igneous rocks.

abstract: M.Sc.


title: Detection of Antibiotic Resistance in Enterococcus spp. by Growth Kinetics Measurements in the Presence of Vancomycin Using the Detection System from TECTA-PDS

contributor:
Brown, Stephen
Environmental Studies

subject: Antibiotic resistant bacteria

abstract:
The spread of antibiotic resistant organisms has increased in different water environments. This originates from the disposal of antibiotics from hospital wastes, irrigation from farms, domestic antibiotic drug disposal in sewage, pharmaceutical production wastes and effluents from wastewater treatment plants. Antibiotic resistant bacteria (ARB) are capable of spreading their genes into water indigenous microbes, circulating in the water environment and potentially altering microbial ecosystems. Antibiotic resistance in water environments are considered contaminants of emerging concerns (CEC), based on the UN and WHO groups and as such becoming a major global health issue in the future.
This project focuses on establishing a rapid, cost effective and easy-to-use, on-site method that will aid in quantifying the ARB, specifically vancomycin resistant Enterococcus (VRE), in water using TECTATM pathogen detection system. This method can potentially be incorporated as part of on site and in lab water quality controls and monitoring assessments. Specifically, this project focuses on establishing a resistance profile for 160 Enterococcus spp. isolates from local wastewater treatment plants for their resistance to vancomycin using the microdilution assay method. The resistance profile established will be used to assess the accuracy of the TECTA system from TECTA-PDS (Kingston, ON).
The TECTA system as a new detection method for ARB, has proved to be effective in detecting the growth of Enterococcus spp. isolates in the presence of low and high concentrations of vancomycin. In comparison to the microdilution assay, the TECTA instrument detected resistance in isolates with an 86.8% agreement with the microdilution assay and a specifically designating resistance at 32 mg/L vancomycin level at a 76.3% agreement.

abstract: M.E.S.


title: Impact of Land Cover Change on Surface Water Temperature from 1985-2020 in Eastern Ontario

contributor:
Chen, Dongmei
Geography and Planning

subject:
Remote Sensing
Land Cover Change
Lake Water Surface Temperature

abstract: Land Cover Change (LCC) has been shown to significantly impact the magnitude and trend of Land Surface Temperature (LST), locally where it occurs. Waterbodies serve as local climate moderators where nearby LCC has the potential to decrease their cooling ability. Water Cooling Islands (WCI) have demonstrated the ability to mitigate these local LST induced changes from LCC. Altered water surface temperatures can lead to altered species migration and distribution in aquatic species depending on a given species thermal boundary. Previous studies investigated the impact of these factors while only targeting either LCC impacts on LSTs or WCI impacts on LST, providing the opportunity to explore the relationship between LCC and WCI temperature trends. In this study, we investigate the role that LCC around small lakes(500m) plays on the surface water temperature trends in the Cataraqui Region Conservation Authority’s watershed, located in Eastern Ontario from 1985 -2020. The Continuous Change Detection Classification (CCDC) algorithm was used alongside the Statistical Mono-Window (SMW) algorithm to calculate LCC and LST, respectively. Results indicated a strong positive relationship (R2 = 0.81) between LCC and water temperature trends, where water temperature trends in all lakes investigated were found to be positive. The land cover type with the strongest correlation of land cover types investigated was with water temperature trends was impervious surfaces which had a medium positive relationship (r = 0.57). Individual lake size was found to have a weak positive relationship (R^2= 0.23) with water temperature trend. This 35-year study contributes to the broader understanding of water cooling islands and the impact of LCC has on surface water temperature trends.

abstract: M.Sc.


title: Towards a postneoliberal health promotion: A journey of reifying, resisting, and reimagining health promotion in and through sport

contributor:
Masuda, Jeffrey
Kinesiology and Health Studies

subject:
Health promotion
Healthism
Sport
Children
Narrative
Post-qualitative
Rope skipping
Neoliberalism
Postneoliberalism
Critical health promotion

abstract:
At its core, this dissertation is about confronting, and working toward dismantling the ideology of healthism as a key technology of neoliberalism, and specifically in how it manifests in and through behavioural forms of health promotion. I enter my interrogation predominantly through sport given that it: is one of neoliberalism’s most spectacular embodiments, is considered by many as inherently health promoting, and is where I was largely enculturated into the ideology of healthism as a young person. Ultimately, the dissertation converges on re/imagining health promotion’s ethical underpinnings, as it endeavours to support optimal human flourishing.
	To achieve the above, through a post-qualitative analytic approach (St. Pierre, 2014, 2018), I offer personal narrative accounts of my lived experiences of, and interpellation into, healthism and behavioural health promotion during the course of neoliberalism’s ascendency, maturation, and solidification over the past three decades. I specifically invoke the activity of rope skipping in my discussion of these matters to demonstrate in a material way the surprising reach that neoliberalism, and healthism specifically, has had into and through the most unsuspecting settings in our society. I also report on an action research project that was both the initial stimulus for, and also a means of grounding the insights that resulted from, the above reflexive investigation.
	The main theoretical contributions of the dissertation are three-fold. First, I advance a novel ethical orientation, critical-relational empathy, to inform future efforts to guide health promotion toward a postneoliberal praxis. Embedded within the idea of, and rationale for, critical-relational empathy is the notion of phronetic justice, where I suggest that behavioural health promotion operates as a kind of epistemic injustice that results in disembodiment, and displacement from person and place, thus inhibiting the phronesis – practical wisdom – that is necessary for human flourishing. I then close by applying the above insights to the context of sport, and rope skipping in particular, by calling for sport’s ‘radical re/wilding’ if it is to be a setting that fosters connection, and thus healthfulness, in and for the postneoliberal era that is now before us.

abstract: PhD


title: Population genetic differentiation and hybridization in the Glaucous Gull (Larus hyperboreus)

contributor:
Friesen, Vicki
Biology

subject:
Larus
Aves
population structure
ddRAD
hybrid
genetic
genomic
Arctic

abstract: Climate change poses a significant threat to the future of Arctic ecosystems. To effectively conserve Arctic species, genetically differentiated populations must be defined for adaptive and neutral genetic variation to be appropriately managed. This project examines population genetic differentiation in the Glaucous Gull (Larus hyperboreus) – a circumpolar Arctic species – and assesses hybridization between Glaucous Gulls and three closely-related species. The Glaucous Gull is a valuable species, biologically and culturally. As apex predators, Glaucous Gulls develop high levels of toxins in their tissue and are, therefore, excellent bioindicators of the long-range transport of contaminants in the Arctic. Glaucous Gulls also hybridize with other white-headed gull species where breeding ranges overlap. Although the International Union for Conservation of Nature currently lists Glaucous Gull as Least Concern, declines have been reported across their range in Arctic Canada. Currently no finescale population genetic information exists for this species, and management units have not been delineated. Double digest restriction-site associated DNA sequencing was conducted on 62 Glaucous Gulls, 18 American Herring Gulls (L. smithsonianus), 6 European Herring Gulls (L. argentatus), and 15 Glaucous-winged Gulls (L. glaucescens) sampled across the North American and European Arctic. Despite the geographic distance between sampling locations, molecular assignments and principal coordinates analysis suggest only weak population differentiation between sampled European and Canadian colonies of Glaucous Gull. Interspecific analyses using 2145 loci show that Glaucous Gull and Glaucous-winged Gull are genetically distinct species but that Glaucous Gull and the two species of Herring Gull are only weakly differentiated. Several sampled individuals may represent hybrids between Glaucous Gulls and American Herring Gulls. Detailed information on population genetic structure and hybridization will help conservation practitioners effectively manage the long-term persistence of Glaucous Gull populations. Proactive management strategies for this species will benefit both Glaucous Gull and the entire Arctic ecosystem.

abstract: M.Sc.


title: Neoliberal Pressures, Neoliberal Responses: The Strategic Utilization of Gender in the Canadian Settlement Sector and Implications for Immigrant Women’s Service Organizations

contributor:
Little, Margaret J. H.
Political Studies

subject:
immigration
integration
Canadian settlement
gender
newcomer women
immigrant women
settlement sector
non-profit sector
neoliberalism
immigrant settlement organizations

abstract:
This dissertation examines the effects of neoliberalism within immigrant women’s service organizations and the delivery of gender-specific programs in the Canadian settlement sector. The influence of neoliberalism within the settlement sector is well-documented. However, little study has focused on immigrant women’s service organizations, programs addressing gender, and the influence of neoliberal practices upon both. This research identifies currently operating immigrant women’s service organizations and women-only program offerings, creating a national map of gender-specific service provision in Canada. Data was obtained via an online survey administered to 189 settlement organizations across Canada, detailing organizational structure, provision and types of gender-specific services, funding experiences, and overall financial outlook, revealing precarity and instability for marginalized and underfunded immigrant women’s service organizations. This research additionally evaluates the prevalence of neoliberalism within settlement organizations and the development of gender-specific programs. Qualitative interviews with 36 employees from mainstream settlement and immigrant women’s service organizations uncovers the incidence and deep infiltration of neoliberal practices, and tactics deployed to counter neoliberal effects. Finally, this research explores “idealized” framings of newcomer women in Canadian society as articulated by newcomers and organizational staff. Qualitative interviews with nine newcomer women were undertaken to inform analyses of neoliberalism within conceptions of the “ideal” newcomer woman.
	The findings of this research reveal connections between neoliberalism, settlement programs, and gender. Drawing upon Jamie Peck’s theory of “roll-back” and “roll-out” neoliberalism, this dissertation identifies a strategic prioritization and utilization of gender within mainstream settlement organizations for the express intent of organizational gain and survival, rather than an ongoing commitment to the advancement of newcomer women. In contrast, immigrant women’s service organizations remain dedicated to gender-specific services for newcomer women even as their organizational work becomes increasingly more difficult due to neoliberal pressures. Findings also suggest neoliberalism influences notions of what is deemed the “good” newcomer woman in Canada, engendering discourses of the idealized newcomer as self-sufficient and market oriented. Collectively, evidence of the strategic prioritization of gender and discourses extolling the virtue of key neoliberal tenets suggests Canadian settlement organizations, programs, and services are entrenched in, and active operatives of, neoliberal practices, ideas, and norms.

abstract: PhD


title: Security by Design: Reducing Information Exchange in Multi-Agent Search Tasks

contributor:
Karen, Rudie
Marshall, Joshua
Electrical and Computer Engineering

subject:
Discrete-Event Systems
Multi-Agent Systems
Exploration

abstract:
Intrinsic to multi-agent systems is the trait of inter-agent dependency on information exchange. During safety-critical tasks, errors in information exchange between agents can lead to vulnerable system behaviour. Consequently, adversarial agents often seek to exploit this vulnerability, rather than exploiting the communicated information itself. Motivated by this problem, the objective of this research is to investigate alternative coordination strategies of multi-agent systems that reduce information exchange and maximize task efficiency.

We consider the task of a multi-agent system of autonomous agents, such as a team of vehicles, performing a reconnaissance mission in an unknown, hostile, and urban environment. We abstract this task by considering a two-agent system exploring an unknown and structured maze. The goal of the agents is to search all states in the maze while minimizing communication and maximizing search efficiency.

Our results demonstrate that through restricting communication to line-of-sight, exploiting the structure of the environment, and employing deterministic decision-making policies, information exchange can be reduced while preserving a high degree of efficiency in the coordination of autonomous agents.

abstract: M.A.Sc.


title: Deep Reinforcement Learning for Packaging Optimization

contributor:
Kim, Il Yong
Mechanical and Materials Engineering

subject:
Deep Reinforcement Learning
Reinforcement Learning
Packaging Optimization
Packing Optimization
Layout Optimization

abstract:
Packing, packaging, and layout optimization is required for efficient systems design within a wide range of industries. The increasing demand for lighter, smaller, and more efficient designs to be rapidly produced has stressed the need for computational tools to solve these optimization problems. Current methods for packing and layout optimization remain limited to simple examples and are not scalable to the complex packaging optimization problems encountered in industry. Recent advancements in computational power and memory have permitted the adoption of reinforcement learning (RL) for various applications. The development of multi-agent reinforcement learning for multi-agent systems has broadened the variety of tasks that can be modelled with RL. The rapid development of RL methods has prompted the investigation of deep reinforcement learning (DRL) for optimization. Due to the inherent properties of DRL, it may present several advantages over current packing optimization methods. Further investigation is required because the application of DRL for practical optimization tasks remains limited.
In this work, an investigation of deep reinforcement learning for packaging optimization is presented. The methodology for formulating packing optimization problems as an RL task is proposed. The selection of an appropriate single and multi-agent algorithm for implementation is discussed. Several algorithm formulations are trained and tested to assess the performance of DRL for packing optimization. The multi-agent framework is more effective due to the ability for multiple agents to coordinate and be conditioned on localized behaviour. Many high quality solutions to the four square packing problem were obtained. Stochasticity was successfully incorporated with exploration to produce higher quality results. Although the algorithm showed the ability to inherently learn heuristics, alternate reward structures may be required to teach the agents to refine the solution. The poor performance of the proposed method for the four shape packing problem revealed the need for an improved overlap constraint penalty. For complex shapes, a more sophisticated exploration scheme is required to effectively search the multimodal packing space. This work lays the groundwork for further study of DRL for packing optimization and demonstrates the merit of future study of DRL for complex packaging optimization.

abstract: M.A.Sc.


title: Time-Dependency and Long-Term Strength of Rocks - Limitations, Interpretation, and Application in Finite Difference Continuum Models

subject:
creep
time-dependency
rock mechanics
numerical modelling
brittle behaviour
long-term strength

abstract:
Many constitutive models have been developed to aid the engineer or scientist in the analysis of material yielding and deformations in the field of rock mechanics. Many of the classical constitutive formulations used are based on instantaneous shearing, or block rotation, but special considerations need to be made when ductile or brittle time-dependent instabilities might arise.  These time-dependent effects lead to an accumulation of strains, or even delayed rupture, that cannot be captured using classical constitutive models.

The research in this thesis provides an overview of several constitutive models developed for the analysis of time-dependent deformations both at the laboratory and excavation scale. This thesis explores several aspects of time-dependent creep and rupture behaviour for ductile and brittle rocks, respectively. Emphasis is placed on how the different creep material models behave in a numerical model as well as exploring their respective limitations and the effect of boundary and loading conditions on their deformation behaviour.

This thesis also further develops the understanding and scientific approaches taken to the testing and interpretation of long-term strength data for brittle rocks. A new proposed methodology and error analysis technique is proposed for analyzing and curve fitting time-to-failure data based on a lower boundary strength limit related to the crack initiation strength threshold. Observations made about the limitations of constitutive creep models and time-to-failure data are used to employ a new numerical model applied at the laboratory and tunnel scale. The model is shown to be able to effectively account for confinement effects in brittle creep as well as capture a pseudo-tertiary creep stage based on simple curve fitting techniques.

The work presented in this thesis advances the understanding of the applicability of time-dependent constitutive models as well as provides the necessary framework for practical numerical implementation when analyzing brittle rock failure at the tunnel scale, an important factor for future deep geological repository selection.

abstract: M.A.Sc.


title: The Environmental Implications of Transportation Corridors in Northern Canada: A Survey Assessment of the Grays Bay Road and Port Project

abstract: Road network expansion plays a significant role in shaping the environment, contributing to the current ecological crisis and climate emergency. Roads provide beneficial transportation services to communities, access to goods and services, and increased economic prosperity. However, the construction of new roads and road improvements are controversial due to their negative environmental impacts. Of particular concern are the impacts of building first-cut resource roads through intact wilderness ecosystems, as they open wild places to a cascade of new development. While the majority of Canada’s northern territory currently remains intact, maintaining this unfragmented land from the threat of development is an urgent task. Understanding the impacts of such road development and planning accordingly is critical to mitigating future long-term environmental effects. To understand the influence of roads in northern Canada, this study considers the current transportation networks in the territories of Yukon (YT), Northwest Territories (NWT), and Nunavut (NU). A literature review was completed to understand the negative environmental impacts of roads under Arctic conditions, including on wilderness character, wildlife, vegetation, atmosphere, hydrology, permafrost, and marine ecosystems. This review informed a survey analysis on the proposed Grays Bay Road and Port (GBRP) project being considered in Nunavut. This research aspires to highlight Canada’s role and responsibility in mitigating the negative environmental impacts of road development in the Arctic, which can be achieved with more stringent land use planning, cumulative impact assessments, and ecological remediation. This will inform future road projects in considering whether the perceived benefits of road network expansion outweigh the irreversible impacts on northern landscapes.


title: The Application of Distributed Optical Sensing to Measure the Full-Field Strain Response of Uniaxial Compression Test Specimens

subject:
Distributed Optical Sensing
Uniaxial Compression Testing
Strain Response Measurement

abstract: The uniaxial compressive strength (UCS) test is crucial in determining the strength and stiffness behaviour of intact rock and is frequently utilized by industry to determine project site characteristics. A fundamental component of UCS testing is measuring the strain response of test specimens. Conventionally, discrete strain measuring devices such as extensometers and/or electric foil strain gauges are used to measure the strain response at the mid-height of a specimen. However, this ultimately limits the ability to capture the full-field strain of UCS tests which has led to a gap in knowledge related to the complexities of the strain response caused by factors such as specimen heterogeneity and the influence of platen friction effects. This research integrates a novel distributed optical strain sensing (DOS) technology with UCS testing to develop a DOS-UCS technique for measuring the full-field strain response of UCS specimens. Unlike conventional discrete strain measurement methods, the optical technique captures a distributed strain profile along the length of a standard, low-cost single mode optical fiber with a resolution of 0.65 mm. In this regard, the following research has been devoted to developing a technique whereby optical strain sensors are installed on the surface of UCS specimens in order to measure the dynamic full-field strain response during UCS tests. The development of such a technique is a non-trivial undertaking as it has never before been implemented within the geomechanics community. To optimize the DOS-UCS technique a comprehensive laboratory testing program was carried out. The results from the testing program demonstrates the capability of the DOS-UCS technique to capture complex full-field strain profiles of UCS specimens, agreeing well with traditional strain measurement techniques. The results also demonstrate the non-uniformity of strain and deviation from continuum behaviour that takes place in UCS tests, particularly after yielding begins. Overall, it was determined that the DOS-UCS technique can capture the complexities of the strain response during UCS testing at an unprecedented level, overcoming the limitations of conventional strain monitoring.

abstract: M.A.Sc.


title: Exploring measurement and ground thermal influences of snow depth in Nunatsiavut, NunatuKavut and Nitassinan

contributor:
Way, Robert
Geography and Planning

subject:
Snow Measurement
Permafrost
Labrador
Cryosphere-Vegetation Interactions
Energy Balance
Numerical Modelling

abstract:
Snow depth is an essential climate variable critical to global energy balance, basin scale hydrology, vegetation change and human livelihoods. It holds special significance in Indigenous northern communities such as those found in Nunatsiavut, NunatuKavut and Nitassinan (Labrador) where changes to snow depth can be hazardous to infrastructure, travel and cultural activities. The energy exchange between snow and ground thermal regime is of particular concern as permafrost distribution has been found to be highly influenced by snow onset/melt and redistribution in Labrador. Our understanding of snow and the impact it has on vegetation and permafrost is hindered by large spatial and temporal gaps in snow measurement and biases toward urban centres that may not be representative of environmental conditions. This thesis expands our understanding of snow characteristics through development of a new, low-cost snow observation technique and through the application of a numerical model that links snow variability to ecosystem and ground thermal processes.
This thesis introduces the snow characterization with light and temperature method (SCLT) for determining snow depth using vertically arranged light and temperature loggers. SCLT data was collected for one year at six remote field sites located in forest and shrub-tundra environments in eastern Labrador. Three different approaches to analyze SCLT data are presented and results are compared to a temperature-only approach applied by prior studies. The results show that SCLT can definitively be used to estimate snow depth accurately. A sensitivity analysis is then performed using the Northern Ecosystem Soil Temperature (NEST) model to consider snow-vegetation-permafrost interactions in Labrador. Preliminary simulations at two sites in coastal Labrador show no significant ground temperature warming over 1979-2018 at the top of permafrost/ base of the freeze-thaw layer for most snow/ vegetation conditions. Findings support previous research that wind scouring controls permafrost distribution at the southern end of the discontinuous permafrost zone. This thesis demonstrates the need to integrate snow, geomorphological and ecosystem science together and that measurement of snow depth in diverse environments is required to anticipate changes in the cryosphere in Nunatsiavut, NunatuKavut and Nitassinan.

abstract: M.Sc.


title: Application of Termitaria Geochemistry to Iron Oxide Copper Gold Exploration in the Kitumba District, Central Zambia

subject: IOCG Termite Termitarium Exploration Kitumba

abstract: Identification and delineation of deeply buried mineral deposits has gained importance with the continuous increase in demand for commodities, specifically regarding Iron Oxide Copper Gold (IOCG) deposits, because of the multitude of metals they commonly contain. Termitaria offer an excellent sampling medium because the material they are comprised of includes inorganic detritus from depths down to 70 metres, depending on water table depth. Composite sampling of termitaria has been the standard method with no delineation of which portion or which grain size of termitaria offer the best results. Furthermore, no known studies have focused the application of termitaria sampling as an exploration method for IOCG deposits. Throughout the research conducted in this study, optical mineralogy, scanning electron microscopy and X-ray diffraction were utilized to distinguish the mineralogy of termitaria samples. High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS) was utilized to ascertain the differences of aqua regia and four-acid digestion for the bulk geochemistry of various grain size fractions including clay, <63 µm, 63-125 µm, 125-250 µm, 250-500 µm, 500-1000 µm, and >1000 µm. Utilizing bivariate scatter plots, stacked cluster columns, and logarithmic line graphs, relationships among the elements determined that aqua regia and four-acid digestion follow similar trends, albeit lower concentrations were found with aqua regia. Standard deviation of sample groupings was utilized to express homogeneity and heterogeneity among grain size fractions and termitary sample locations. It was found that the clay size fraction held the highest concentrations for elements often associated with IOCG deposits, including Co, Cu, La, Mo, Sb, U, and W. It was also discovered that the clays had anomalous concentrations of Ba, Bi, Cr, Cu, Fe, K, Mn, Mo, Tl, and W in comparison to background values and Bi, Co, Cu, Ge, Mo, Sb, SN, U, V, and W in comparison to average crustal abundance. Composite sampling of termitaria is supported in this study with no evidence that the top, bottom, or inside of the mound has consistently higher element concentrations.

abstract: M.Sc.


title: Institutional Feedback and Coalition Politics: The Case of School Choice Policies in Advanced Democracies

contributor:
Amyot, G. Grant
Banting, Keith G.
Political Studies

subject:
Comparative Politcs
Comparative Education Policy
Education
Historical Institutionalism
Coalition Analysis
Sweden
France
United States

abstract:
This dissertation seeks to identify the political forces that have driven the shift towards school choice in advanced democracies and to explain the variation in policy outcomes observable in these countries. To do so, it examines reforms introduced between 1985 and 2017 in France, Sweden, and Wisconsin, which all moved towards school choice, albeit with varying levels of enthusiasm and immediacy.
The main argument defended in this dissertation is that the policy outcomes in each country are the result of the interaction of institutional dynamics and coalition politics. Two institutional dynamics were important in the politics of school choice: institutional feedback effects, which shaped the contestants in each political battle and veto points, which slowed the pace of change. This analysis especially emphasizes the role of negative feedback effects in each country. Educational institutions in Sweden, France, and Wisconsin stimulated a different set of group grievances. Actors who saw themselves as disadvantaged had incentives to call for reform and collaborate with other actors who had similar goals. In other words, negative feedback effects created a different pattern of grievances that political actors mobilized. In all three countries, the strength and stringency of veto points influenced the pace of change.
These institutional dynamics interacted with coalition politics. Political parties in particular but also civil society organizations articulated the grievances of the groups angered by education policy. The policy coalitions they built varied in size, duration, and in the type of social interests they incorporated. School choice proponents in Sweden built the strongest and most stable coalition. The American coalition was narrower and incorporated strange bedfellows: religious groups, market conservatives, and African American activists. Finally, French policymakers could not build a coalition that was strong or stable enough to implement their policy agenda. The composition of policy coalitions influenced the outcome of the reform process. In Sweden, the change was deep and universal, while it was shallow and targeted to particular groups in France. In Wisconsin, both shallow-universal and deep-targeted changes were introduced. In combination, the institutional dynamics and coalition politics explain the patterns of educational policy change across these three countries.

abstract: PhD


title: Control and Learning for Robotic Excavation

contributor:
Marshall, Joshua
Mechanical and Materials Engineering

subject:
robotic excavation
mining robotics
autonomous loading
admittance control
iterative learning
material classification
construction robotics
loader automation

abstract:
Despite a large body of research and engineering work in robotic excavation, spanning decades, commercially viable systems for fully autonomous excavation are still in their infancy. The challenge is that performance is strongly influenced by the conditions of interaction between the excavator and the material, which are typically unknown and changing throughout an excavation process. For example, material such as fragmented rock, is not homogeneous in size and composition, can be wet and sticky, or dry, depending on local factors, and it inherently moves and exposes new hidden material that is not visible prior to executing the excavation process. Thus, a fully autonomous solution for robotic excavation requires adaptation to these changing conditions in order to achieve consistent bucket filling performance.

The robotic excavation research presented in this thesis focuses on the development and study of control and learning approaches for autonomous loading of fragmented rock using robotic load-haul-dump (LHD) machines, which are utilized in underground mining; although, the developed approaches are applicable to surface loaders as well. Using an admittance-based dig control strategy for autonomous loading---which uses force feedback to regulate motion commands to a loader's bucket actuator for autonomous digging and loading---as a base control framework, preliminary field experiments are conducted with a 14-tonne capacity robotic LHD machine to gain insights into the science of the autonomous loading process. These insights are used to improve the overall dig controller design, which increases the controller's robustness and facilitates consistent bucket filling performance. This robust and consistent base control framework enables the use of simple learning algorithms to adapt the controller to changing material characteristics. An iterative learning algorithm is developed and validated,  which adapts control parameters to track a desired bucket fill weight at each excavation pass. A material classification methodology is also developed and validated, which uses information in the controller's force feedback signal to classify excavation materials to further improve learning and adaptation. Compared to AI-based approaches that require many training samples and advanced computing, the developed control and learning approaches have practical significance as demonstrated through the full-scale field experiments.

abstract: PhD


title: HIGH-DOSE WEEKLY CARFILZOMIB, CYCLOPHOSPHAMIDE, AND DEXAMETHASONE IN THE TREATMENT OF PATIENTS WITH RELAPSED AND REFRACTORY MULTIPLE MYELOMA – EXPLORING THE FINANCIAL COST AND RARE SIDE-EFFECTS

contributor:
Hay, Annette
Pater, Joe
Translational Medicine

subject:
Multiple Myeloma
Carfilzomib
Weekly KCD
Cost-analysis
Thrombotic Microangiopathy

abstract:
Multiple myeloma
Multiple myeloma (MM) is a malignant disorder of clonal plasma cells based in the bone marrow  that leads to devastating symptoms including renal failure, hypercalcemia, anemia, and fractures. Treatment efficacy has improved due to the advent of new therapies; however, there is also an increase in toxicity and cost (1,2).
MYX.1 Trial
The MYX.1 clinical trial is a single arm phase II multi-centre trial that explored the efficacy of high-dose weekly carfilzomib with cyclophosphamide and dexamethasone (wKCD) for relapsed MM.  The trial met its primary endpoint with a high overall response rate (84%) (3)
Life-threatening Drug Side-effects
Cases of thrombotic microangiopathy (TMA), a rare but life-threatening syndrome of microangiopathic haemolytic anaemia, thrombocytopenia, and multi-organ dysfunction, have been reported in patients receiving carfilzomib (4–8).   Herein, I will determine the incidence, clinical phenotype, and predictive factors associated with TMA and carfilzomib based on the MYX.1 trial data.
Cost of Myeloma Therapy
In Canada, MM represents 1.5% of cancer diagnoses but up to 20% of some provincial oncology drug budgets (G. Mitera, personal communication, March 30, 2020).  MM is not curable, and treatment is continuous until the time of disease progression.  This study determines the cost of high-dose wKCD, from the perspective of the payer, based on MYX.1 trial data.
Results
A high rate of TMA (4%) was seen in patients treated in the MYX.1 clinical trial.  The management of carfilzomib related DITMA should focus on supportive care and cessation of carfilzomib.
Based on the MYX.1 trial data, the mean total cost of high-dose weekly KCD was $203,336.08 CAD per patient (pt).  The predominant cost driver was chemotherapy at $179,332.78/pt where the cost of carfilzomib was $162,471.65/pt.  The cost of carfilzomib is minimized through this high-dose once weekly KCD dosing schedule. We calculated the cost of biweekly carfilzomib at $300,576.70/pt (compared to $179,332.78 per patient on wKCD), a potential cost savings of $104,663.43/pt from direct drug costs and $16,580.49/pt from drug administration costs.
Conclusions
High-dose wKCD is an active triplet regimen for RRMM associated with reduced total cost compared with twice weekly regimens and its toxicity is provisionally acceptable.

abstract: M.Sc.


title: The Clarity of Understanding

contributor:
Paul, Elliot
Philosophy

subject: understanding consciousness epistemology know-how abilities phenomenology grasping testimony

abstract: A platitude about understanding is that it involves grasping. But what is grasping? In this thesis, I develop a novel account of grasping that is rooted in phenomenal consciousness. According to this account, grasping is a matter of having a distinct kind of conscious experience: clear perception. Clear perception has a distinct cognitive phenomenology that characterizes it. Call this the clarity account of grasping. I go on to argue that the dominant view of grasping in the literature, the ability account of grasping, is false. Using the new clarity account, I argue that grasping is not only distinct from the cognitive abilities associated with understanding, but also explanatory prior to them. Finally, I argue that the clarity account implies that understanding cannot be transmitted through testimony, because clear perception cannot be acquired on the basis of testimony. As such, clear perception plays key cognitive and epistemic roles in understanding and coming to understand.

abstract: M.A.


title: FACTORS AFFECTING GCL SELF-HEALING AND ITS SUBSEQUENT HYDRAULIC PERFORMANCE

contributor:
Rowe, Kerry
Civil Engineering

subject: Geoenvironmental Geosynthetics

abstract:
A number of researchers have studied GCLs’ self-healing capacity, however, most examined either regular holes or relatively benign hydrating/permeating fluids not representative of typical field applications. This thesis addresses this gap by firstly investigating the self-healing of regular holes/slits when hydrated from: unlimited benign and simulated cation rich pore fluids, subgrade with pore fluid limited by the subgrade gravimetric moisture content. The thesis then examines the self-healing of irregular holes/slits formed by downslope bentonite erosion in both laboratory and field experiments when rehydrated on Godfrey silty sand (GSS). Additionally, the hydraulic performance of GCLs after self-healing was assessed for specific scenarios.
The hydrating fluid chemistry was found to impair the self-healing capacity of GCLs with regular holes/slits under both relatively ideal conditions where there was sufficient hydrating fluid available (simulating pond applications) and conditions where GCLs hydrated from GSS with only limited hydrating fluid available from the pores (simulating common field conditions) and increased hydraulic conductivity due to cation exchange. This was corroborated by findings from a control test on silica sand with similar characteristics to GSS. The results suggested that when designing a containment facility, holes smaller than 15 mm-diameter are able to self-heal and not likely to have a significant impact on the hydraulic performance of the liner system, while holes greater than 25 mm-diameter should be of concern to designers.
Field eroded GCL specimens with irregular holes/slits showed notably less self-healing than laboratory eroded and virgin GCL specimens when rehydrated from GSS with limited pore fluid, owing largely to the cation exchange the bentonite had experienced in the field. The post-hydration hydraulic conductivity of GCL specimens with holes/slits was about 1~4 orders of magnitude higher than that of an intact specimen. For a 0.3m design hydraulic head, a single or few such eroded holes/slits may not be of a great concern in terms of increase in leakage monitoring, however, that would change if there were many (e.g. 100) or much longer (e.g. 10~20 m-long) defects per ha, which may not be acceptable for containing landfill leachate.

abstract: PhD


title: Investigating Long-term Environmental Trends in Central Ontario Lakes Impacted by Cyanobacterial Blooms

contributor:
Smol, John
Paterson, Andrew
Biology

subject:
blue-green algae
paleolimnology
climate change
aquatic ecology

abstract:
Cyanobacterial blooms degrade water quality by increasing turbidity, causing taste and
odour problems, depleting deep-water oxygen concentrations, and producing toxins – all of
which can alter aquatic food webs, and depreciate the social and economic value of waterbodies.
A common driver of blooms is nutrient enrichment; however, climate-related factors, like surface
water temperature, intensity and duration of thermal stratification, precipitation, and wind speed,
are also important predictors. Consequently, climate change is expected to increase the spatial
extent, severity, frequency, and duration of cyanobacterial blooms. Reports of blooms have
increased in recent decades in Canadian lakes, but a lack of long-term monitoring hinders
attempts to identify the causes. This thesis examined environmental indicators preserved in lake
sediment cores to reveal multi-century trends in water quality and investigate drivers for these
recent cyanobacterial blooms. In a remote oligotrophic lake, marked increases in cyanobacterial
microfossils in surficial sediments and an increasing trend in primary production since ~1930
CE, in the absence of nutrient enrichment, suggest a climatic driver for recent unprecedented
Dolichospermum blooms. In three rural northeastern Ontario lakes, eutrophication in ~1930 CE
potentially associated with forest removal and settlement was tracked in diatom assemblages in
two of the lakes. However, bloom occurrence in these lakes over a half-century later was
associated with distinct diatom species shifts, indicative of enhanced thermal stratification. In
Callander Bay, Lake Nipissing, a climate-mediated shift from polymictic conditions to sustained
summertime stratification, and increased bottom water anoxia and internal nutrient loading since
~2000 CE, are linked to recent cyanobacterial prevalence. At eight additional sites across Lake
Nipissing, diatoms in modern and pre-industrial era sediments revealed strikingly similar
assemblage shifts indicative of lake-wide enhanced thermal stratification, indicating more favourable conditions for blooms. Estimates of baseline nutrient and hypolimnetic oxygen
concentrations derived in this study can be used to guide management targets. Collectively,
increasing primary production tracked over the last several decades (without parallel increases in
nutrient enrichment) across all study lakes has likely occurred due to regional warming and a
longer ice-free growing season, and invokes climate change as an important driver of
cyanobacterial blooms in temperate lakes.

abstract: PhD


title: Subversive Intimacies: Resisting Settler Colonialism's Shallow Attachments

contributor:
McKegney, Sam
English Language and Literature

subject:
Settler Colonialism
Indigenous studies
Environmentalism
Anthropocentrism
Solidarity
Animal studies
Diaspora
Kinship

abstract: Gathering texts by Indigenous and non-Indigenous artists and authors, this dissertation asks, how does settler colonialism depend on disjointed and shallow attachments, and how do Indigenous and non-Indigenous artists respond to and rise above the asociality of this structure? I draw on a range of creative responses—graphic novels, music, poetry, fiction, activism—as a means of assessing how Indigenous and non-Indigenous peoples creatively respond to settler colonialism’s shallow attachments. The multifocal, multilocal exploration—different theoretical standpoints, historical moments, territories, and traditions— is part of understanding the settler colonial assemblage and the many ways in which creative production resists, subverts, and exceeds this structural oppression. Several warp threads run through this dissertation to hold this project together: settler-colonialism, Indigenous knowledge, diaspora, racialization, biocapitalism, relationality and asociality, solidarity, anthropocentrism and the anthropocene, intimacy, embodiment, and place.

abstract: PhD


title: CURATORIAL CONTESTATIONS: CHALLENGING INSTITUTIONAL MODES OF INCLUSION IN THE ARTS THROUGH CURATORIAL POSITION(S) AND PRACTICE(S)

contributor:
Robinson, Dylan
Taunton, Carla
Cultural Studies

subject:
curatorial studies
curatorial practice
museum studies
museum theory
contemporary art
visual culture
cultural studies
decolonial aesthetics
decolonizing methodologies
exhibition theory
critical art history
Canadian studies
research-creation
critical settler studies
Indigenous methodologies

abstract: In today’s climate of political unrest, art institutions and curators play increasingly important roles, serving (their) varied constituencies and cultural communities by creating meaningful points of contact with diverse materials and representational practices. Nevertheless, institutions and curators continue to perform neoliberal politics through mere inclusion that does not reckon with necessary structural change. This dissertation responds to how art exhibitions and art institutions have recentred whiteness through their representational logics, with case studies that unsettle traditional curatorial methods and methodologies. More specifically, it explores three distinct curatorial approaches to spatially and conceptually laying out an exhibition in the gallery that offer decolonizing potential: (1) juxtapositional contrast; (2) intertextual simultaneity and layering; and (3) re-oriented sightlines and entry points. Drawing on Black, Indigenous, feminist, queer, diasporic, and critical settler writings and pedagogies, this project seeks to reveal alternative ways of working with and representing BIPOC artists and histories in relation to curatorial subject positions and institutional contexts.

abstract: PhD