title: PKA INHIBITION DURING FGD1 DYSREGULATION UNMASKS A DOMINANT ROLE FOR RHOGDI⍺ IN COORDINATING THE ANGIOGENIC ACTIONS OF CDC42

contributor:
Maurice, Donald H.
Translational Medicine

subject:
PKA
RHOGDI⍺
Angiogenesis
Podosome Rosettes
Endothelial Cells
Cdc42
FGD1

abstract: Angiogenic sprouting, the growth of blood vessels from pre-existing vasculature, underlies normal development, but its dysregulation contributes to the pathologies of life-threatening medical conditions, including cancer and ischemic heart disease. During angiogenesis, in response to the gradients of pro-angiogenic signals, select endothelial cells (ECs) take on a “tip” cell phenotype to guide the blood vessel formation towards avascular areas. The mechanisms that govern the EC-guided remodelling of the vascular basement membrane to subsequently sprout new blood vessels is still in its infancy. The studies presented in this thesis examine the involvement of cyclic adenosine 3’,5’-monophosphate (cAMP) second messenger-signalling through the integration of cAMP effector proteins, protein kinase A (PKA), in EC actions during angiogenic sprouting. At a molecular level, I demonstrate a role for PKA in the context of a promising cell division control protein 42 homolog (cdc42)-selective guanine nucleotide exchange factors (GEF), Faciogenital dysplasia protein 1 (FGD1). At a cellular level, I found that FGD1-mediated activation of cdc42 is key in regulating the signal transduction pathways that promote podosome rosette formation in ECs during angiogenic stimuli, as seen with transforming growth factor-beta (TGFβ) and vascular endothelial growth factor (VEGF), in the presence of PKA. While FGD1 appears to regulate the levels of active cdc42 generated in response to VEGF, it does not play a dominant role in cdc42 effects in the absence of PKA. Interestingly, it was found that in the absence of FGD1, cells can use guanosine dissociation inhibitor ⍺ (GDI⍺)-based cdc42 sequestration as a dominant regulator of active cdc42 levels. Given these results, I investigated the possibility that FGD1 is a PKA substrate and phosphorylation of FGD1 would inhibit its activity. It was found that FGD1 is unlikely to be phosphorylated by PKA in these ECs. The increase in podosome rosette formation in the absence of FGD1 with PKA inhibition allows the opportunity to explore the role of other cdc42 mediators to uncover dominant regulatory mechanisms. Overall, our work studying the role of PKA in angiogenic ECs in the context of FGD1, a dominant cdc42-selective GEF, provides insight into cAMP regulation of these sprouting angiogenic pathways.

abstract: M.Sc.


title: EVALUATING THE GASTROINTESTINAL MICROBIOTA OF HOSPITALIZED NEONATES USING CULTUROMICS AND METAGENOMICS

contributor:
Sheth, Prameet
Vanner, Stephen
Translational Medicine

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:
Newborn
Culturomics
Metagenomics
Neonate
Microbial communities
Gut microbiome
Gastrointestinal microbiome
Bacteria isolation
Mass spectrometry
16S rRNA

abstract: Background: The developing gastrointestinal microbiota (GIM) of neonates plays an important role in long and short-term health. ‘Culturomics’, the use of specialized media in conjunction with metagenomics has the potential of providing further insight into the isolation and identification of bacterial populations in the GIM that so far have been overlooked for their health benefits. This study aims to better characterize the GIM of neonates in the NICU through high-throughput culturing methods and metagenomics. We hypothesize that by enriching bacteria found in neonatal stools, our team will identify previously unappreciated fastidious anaerobes in the neonatal GIM. Methods: Using a culturomics approach, we isolated bacterial species from the stools of low birth weight (LBW) and normal birth weight (NBW) (n=10) neonates in the NICU who were unexposed to probiotics or antibiotics. Stool was cultured either immediately on 8 different selective and differential media or preincubated in blood culture bottles with or without sheep blood and rumen fluid supplementation before culturing on selective and differential agar. Bacteria were identified using MALDI-TOF mass spectrometry and/or 16S Sanger sequencing (V3-V4) hypervariable regions). Results: Culturomics allowed for the isolation of 33 species of bacteria from the neonatal stool within the 5 families identified through 16S Next-generation Sequencing (NGS); Enterobacteriaceae, Staphylococcaceae, Enterococcaceae, Bacteroidaceae, and Streptococcaceae. Enrichment allowed for the isolation of 11 bacterial species not previously identified in the unenriched conditions including S. haemolyticus, S. parasanguinis. V. rogosae, and R. solanacearum and resulted in more fastidious anaerobes being recovered. Conclusions: Future studies investigating neonatal GIM should utilize both culturomic and metagenomic approaches. These studies will increase our understanding of the membership of the neonatal GIM and provide insight into the role of fastidious bacteria in the neonatal GIM and neonatal health.

abstract: M.Sc.


title: Comparison and Continuity Properties of Equilibrium Values in Information Structures for Stochastic Games

contributor:
Yuksel, Serdar
Mathematics and Statistics

subject:
Stochastic Team Theory
Stochastic Game Theory
Information Structures

abstract:
In stochastic games where players measure a cost-relevant exogenous state variable through measurement channels, an information structure is the joint probability measure induced on the state space and player measurement spaces.

For single-player decision problems in finite spaces, a theorem due to Blackwell leads to a complete characterization of when one information structure is "better" than another. For zero-sum games with finite state, measurement, and action spaces, Peski produced necessary and sufficient conditions for ordering information structures. In this thesis, we obtain an infinite dimensional (standard Borel) generalization of Peski's result. A corollary is that more information cannot hurt a decision maker taking part in a zero-sum game. We also establish two supporting results which are essential and explicit, though modest contributions to the literature: (i) a partial converse to Blackwell's ordering in the standard Borel  setup and (ii) an existence result for equilibria in zero-sum games with incomplete information.

Then we study continuity properties of stochastic game problems with respect to various notions of convergence of information structures. For zero-sum games, team problems, and general games, we will establish continuity properties of the value function under total variation, setwise, and weak convergence of information structures.

abstract: M.A.Sc.


title: Down the TikTok Rabbit Hole: Testing the TikTok Algorithm’s Contribution to Right Wing Extremist Radicalization

contributor:
Murakami Wood, David
Sociology

subject:
Violent Extremism
Radicalization to violent extremism
Far Right
TikTok
Conspiracy Theory
Algorithmic Radicalization
Loneness
Radicalization
Social Media
Right Wing Extremism
For You Page
Online Radicalization
Digital Radicalization
Banalization of far-right narratives

abstract:
(EN) Using a new moderately conservative TikTok profile, and insight from an auto-ethnographic exploration, this study suggests TikTok’s loose guidelines, inaction, and recommendation algorithms have the potential to contribute to an individual’s radicalization process. The platform’s recommendations, after watching a thousand videos, were increasingly radical in nature, in content, and in tone, ultimately sending the profile into conspirational echo chambers. I suggest this trend, and the ensuing echo chambers, challenge individual protective factors for radicalization, contribute to banalize fringe and far-right narratives, and thus warrant additional research and investigation. This is particularly true as I observed substantial bridging between narratives, starting from mainstream conservative political material toward antivaxxer material, hypermasculinity, TikTok’s Hatescape, a conspiracy rabbit hole, socialization and education on hate or dissidence, and even some calls for and demonstration of violence. The platform progressively recommended a significant variety of hateful, far-right, and conspirational themes and narratives, with the potential to appeal and play upon an equally variable range of vulnerability factors and cognitive openings. Likewise, content creators appear to know how to navigate TikTok’s lacking enforcement of community guidelines and play upon current events, feelings, and emotions. The literature suggests that radicalization is a fluid process where actors’ involvement can vary in role and activity, and in its (il)legality. From my observations, I conclude with the need for further research and studies on comment sections, in their role in education, participation, and socialization in potentially radicalizing actors. I further suggest paying additional attention to, and would recommend empirical research of, the change in individuals’ activities on- and offline as a result of their socialization on the platform.

(FR) En utilisant un nouveau profil TikTok modérément conservateur et des informations issues d'une exploration auto-ethnographique, cette étude suggère que l'inaction et les algorithmes de recommandation de TikTok ont le potentiel de contribuer au processus de radicalisation d'un individu. Les recommandations de la plateforme, après avoir visionné un millier de vidéos, étaient de plus en plus radicales dans leur nature, leur contenu et leur ton, envoyant finalement le profil dans des chambres d'écho complotistes.

abstract: M.A.


title: Olfactory Bulb Proteome Changes in Response to Alzheimer's Disease-Related Pathologies in Mouse and Rat Models

contributor:
Kawaja, Michael
Neuroscience Studies

subject:
Alzheimer's Disease
Olfactory Dysfunction
Olfactory Bulb

abstract: Alzheimer’s disease (AD) is the most common cause of dementia, and it is one of the leading causes of death globally. Identification and validation of biomarkers that herald the onset and progression of AD is of paramount importance for early reliable diagnosis and effective pharmacological therapy commencement. A strong correlation between olfactory dysfunction and AD onset and progression in humans exists, however, the underlying mechanism remains unknown. There remains a paucity of information regarding the olfactory proteomes from AD-like mouse and rat models. The purpose of this study was to address this knowledge gap by conducting comprehensive proteomic analyses of the olfactory bulb to reveal potential novel AD biomarkers. This study aimed to identify proteins that may contribute to olfactory dysfunction as a consequence of central amyloidosis and/or presenilin 1 mutations in AD-like mouse and rat models. Using 2D gel electrophoresis and silver staining, we detected proteomic differences in 9-month-old TgCRND8 mice and 10-month-old TgF344 rats compared to their non-transgenic littermates run at pH 4-7 and pH 7-10. Sex differences were observed in the olfactory bulb proteome in TgCRND8 mice and TgF344 rats. These differences should be explored further as they may provide an explanation for discrepancies between female and male olfaction. Cross-species differences in the olfactory bulb proteomes were also observed. Candidate spots were excised and identified via mass spectrometry. While mass spectrometry results are pending, results for three protein spots were obtained. Notably, membrane-associated progesterone receptor component 1 expression was shown to be increased in male TgCRND8 mice compared to their age- and sex-matched non-transgenic littermates. While further experiments are necessary to provide anatomical and protein-level validation, these preliminary results suggest a potential novel pharmacological target to mitigate olfactory dysfunction experienced by patients with AD. As an extension, proteomes of the olfactory bulb and brainstem/cerebellum were also compared in male TgCRND8 mice and their non-transgenic littermates. Proteomic differences observed between these brain regions suggest that the transgene may be differentially expressed in these areas. Future experiments should be designed to assess whether these findings have translational value from mice and rats to human patients with AD.

abstract: M.Sc.


title: Fantasies of Containment: Entanglements Between the Nuclear Family and Therapeutic Culture in the Making of the Self

contributor:
King, Samantha
Kinesiology and Health Studies

subject:
The nuclear family
Therapeutic culture
Neoliberalism
Postfeminism
Domination through difference
Gender
Productive/Reproductive divide
Ambivalence
Subjectivity
Whiteness
The middle-class home
Containment

abstract: This dissertation is about the way that larger power dynamics are rendered invisible at the very site where they are felt most acutely: in our own bodies and in our most intimate relations. Using the white, middle-class nuclear family as my site of analysis, I explore the way that feelings of guilt and anxiety are often viciously turned against the self in ways that further individualize pain and suffering. The logic of domination through difference is a consistent theme that runs throughout this work: I explore how power is reproduced through a persistent fantasy of control and closure that manifests itself in a variety of ideals, aspirations, and discursive mechanisms associated with the middle-class nuclear family. By examining my parents’ narratives of their marriage, family life, and eventual divorce, I show how containment is offered time and time again as a solution to dysfunction and uncertainty, even as the impulse toward control and containment amplifies or reinforces the structural and psychic conditions that have created tension. I place my parents’ narratives in a larger context of gendered dynamics, neoliberal restructuring, and therapeutic culture in order to both contextualize and depersonalize feelings of dysfunction, blame, and guilt, offering a reflection that might interrupt, however briefly, the individualizing tendencies of normalizing power.

abstract: PhD


title: Family Quality of Life in Ethiopia: Exploring the Perceptions of Family Members of Children with Disabilities and Support Providers

contributor:
Aldersey, Heather M.
Rehabilitation Science

subject:
Family quality of life
Children with disability
Family
Support
Ethiopia
Africa
Spirituality

abstract:
Background: Family quality of life (FQOL) is an important outcome for families of children with disabilities globally; however, minimal research has focused on families in low-income contexts, specifically in Africa. Research has primarily conceptualised FQOL from the perspectives of mothers in high-income countries. Additionally, support provision is associated with improved FQOL, but further research is needed to understand how support can practically meet families’ diverse needs in low-income contexts.
Purpose: This dissertation sought to understand how Ethiopian families of children with various disabilities conceptualise FQOL and how their support needs, and the provision of support contribute to FQOL.
Method: I conducted three inter-related studies, starting with a scoping review to identify factors that contribute to FQOL for families of children with disabilities in African contexts. I subsequently conducted two exploratory descriptive qualitative studies, first with Ethiopian family members of children with disabilities, and then with support providers.
Results: Although similar factors contribute to FQOL internationally, poverty, stigma, and spirituality are particularly prominent in African contexts. In Ethiopia specifically, families experienced significant poverty and stigma, and spirituality was foundational to their lives and FQOL. They also described FQOL in terms of relationships within the family and with community, and they sought self-sufficiency, primarily through education and employment. However, with the enormous responsibilities of raising a child with a disability, they recognised their need for, and overall inadequacy, of support. Ethiopian support providers affirmed the centrality of spirituality, relationships, and self-sufficiency for FQOL, and described various ways they support families, emotionally, physically, materially, and informationally. Yet, they also experienced challenges and needed support to contribute positively to FQOL.
Conclusions: Culture and context influence FQOL, and understanding FQOL from the perspective of Ethiopian families of children with disabilities can help to direct appropriate and feasible support provision. Recognising the foundational role of spirituality, providing holistic support, and awareness-raising to minimise disability stigma are crucial for supporting FQOL. All stakeholders, including families, communities, support providers, and government, must work collaboratively to address the needs of families of children with disabilities to enhance FQOL and allow children with disabilities and their families to truly flourish.

abstract: PhD


title: Dynamic Reinforcement Learning-based Resource Allocation For Grant-Free Access

contributor:
Givigi, Sidney
Abou-Zeid, Hatem
Computing

subject:
Grant-free
Reinforcement Learning
5G
Dynamic Allocation
Ensemble Learning

abstract:
Cellular networks have evolved to deliver high-speed broadband services to support the requirements of IoT applications, which demand high speed, low latency, and massive capacity. A primary market goal is to provide support for ultra-reliable low latency communication (URLLC). Among the use cases enabled by 5G, URLLC is of major importance for mission-critical IoT applications such as smart transporta- tion, industrial automation, telemedicine, tactile Internet, etc. However, URLLC requires below 1 ms radio latency as defined by the third generation partnership project (3GPP). One of the promising technologies to achieve the aforementioned specifications is grant-free (GF) access for uplink resources. The GF scheme enables the user equipment (UE) to transmit data over pre-allocated resources which reduces communication latency. When implementing the GF scheme, two objectives must be jointly accomplished. The first is to optimally select UEs for GF access. The second is to allocate the proper number of resources given to the environment to ensure low latency while minimizing resource wastage. The main challenge in implementing GF access in wireless networks is that the environment can frequently change. This is due to the fact that UEs typically exhibit a wide range of different traffic patterns over time. Furthermore, because the UEs are sometimes mobile, their channel qualities and interference levels vary.
This thesis proposes an intelligent Reinforcement Learning (RL) based allocation technique for GF access that is trained via Deep Q-Learning. RL has the capability to learn the intricacies of the network and the behavior of the connected users to optimize resource allocation without the need for large amounts of labeled data. The results show that the proposed RL scheme was able to enhance the overall transmission latency of UEs for URLLC applications under relatively stable network conditions, achieving less than 20 TTI latency for 95% of the time. Additionally, since the proposed RL-based allocation technique incorporates ensemble learning, the proposed solution was able to cover a wide range of network scenarios. Moreover, the developed RL agent was capable of adapting to dynamic scenarios by updating the configurations to accurately select the stable UEs and the adequate number of resources that reduce wastage and ensures system stability based on the UEs’ feedback.

abstract: M.Sc.


title: Oh The Places You'll Go: The Assessment of Self-Regulation in Grade 1 to 3 Classrooms

contributor:
DeLuca, Christopher
Education

subject:
assessment
self-regulation
self-regulation assessment
primary education

abstract: In the 21st century a greater emphasis has been placed on learning skills, such as self-regulation, to help prepare students for their academic future and time beyond school. Research has indicated a predictive relationship between self-regulation and academic success. As a result, fostering self-regulation has been deemed important in the classroom and is a selected learning skill in the Ontario public school system. In order to foster self-regulation, it is important to explore the assessment of self-regulation. The purpose of this study is to explore how teachers use assessment in the primary classroom to foster, monitor, and track the development of self-regulation. Six Ontario primary teachers (both working in public and private schools) were purposefully selected for the study. This study employed a methodology of interpretive phenomenology, which allowed the participating teachers to share their experience of self-regulation assessment through semi-structured interviews and artifacts. Thematic analysis of the data revealed four themes: self-regulation assessment in primary classrooms, methods for collecting evidence of students’ self-regulation development, assessment to support and promote self-regulation skills, and self-regulation assessment challenges. While there is greater emphasis on learning skills and general agreement about their importance both in terms of academic success and success beyond school, there is a lack of resources and understanding of how to assess these skills. Findings from this study provide insight into various challenges that teachers face in supporting and assessing self-regulation skills.

abstract: M.Ed.


title: Essays on Policy Issues in Non-Pro t Markets

contributor:
Clark, Robert
Economics

subject:
Non-profit markets
Hospitals
Directed mergers
Administered-prices
Charities
CEO compensation
NGOs
Healthcare reform
Closures
Amalgamations
Hospital systems
Choice
Restructuring
Healthcare
Gender pay gap

abstract: This dissertation focuses on policy issues in non-profit markets using tools from the industrial organization and labour literatures. The first essay investigates the impact of hospital closures and mergers. We use data on a large wave of directed hospital mergers and closures in the province of Ontario, Canada to investigate the impact of hospital reorganization on patient welfare. We estimate a model of patient hospital choice on data collected before the reorganization, finding that both distance and hospital quality are determinants of choice. The model is then used to understand the short-run and long-run welfare impact of reorganization. Results suggest that cost savings and efficiency are not the only factors to consider when restructuring in settings where patients do not pay for services. Hospital access and quality must be considered. The second essay investigates the market for senior management in the U.S. charities sector. Using charity-level data from 990 Forms filed for the U.S. Internal Revenue Service, we document two new stylized facts not previously documented in the literature. First, we find that female managers are more likely to receive compensation than male managers. Second, conditional on receiving compensation, female managers receive 8% lower total compensation than their male counterparts. We show the gender pay gap is only present in the largest charities (top two quintiles in the revenue distribution). Both findings are robust to the inclusion of charity classification fixed effects (between estimator) and charity fixed effects (within estimator). Our exploration of mechanisms driving the gender pay gap in this context points out a mismatch between pay dispersion and performance dispersion. While pay dispersion across genders is consistent with organizations perceiving male managers as differentiated unlike female managers, and there are no differences in performance dispersion supporting this perception.

abstract: PhD


title: Multistream Gaze Estimation with Anatomical Eye Region Isolation by Synthetic to Real Transfer Learning

contributor:
Etemad, Ali
Electrical and Computer Engineering

rights: Attribution-NonCommercial-ShareAlike 3.0 United States

subject:
Gaze Estimation
Deep Learning
Eye Region Isolation
Transfer Learning

abstract: We propose a novel neural pipeline, MSGazeNet, that learns gaze representations by taking advantage of the eye anatomy information through a multistream framework. Our proposed solution comprises two components, first a network for isolating anatomical eye regions, and a second network for multistream gaze estimation. The eye region isolation is performed with a U-Net style network which we train using a synthetic dataset that contains eye region masks for the visible eyeball and the iris region. The synthetic dataset used in this stage is a new dataset consisting of 60,000 eye images, which we create using an eye-gaze simulator, UnityEyes. Successive to training, the eye region isolation network is then transferred to the real domain for generating masks for the real-world eye images. In order to successfully make the transfer, we exploit domain randomization in the training process, which allows for the synthetic images to benefit from a larger variance with the help of augmentations that resemble artifacts. The generated eye region masks along with the raw eye images are then used together as a multistream input to our gaze estimation network. We evaluate our framework on three benchmark gaze estimation datasets, MPIIGaze, Eyediap, and UTMultiview, where we set a new state-of-the-art on Eyediap and UTMultiview datasets by obtaining a performance gain of 7.57% and 1.85% respectively, while achieving competitive performance on MPIIGaze. We also study the robustness of our method with respect to the noise in the data and demonstrate that our model is less sensitive to noisy data. Lastly, we perform a variety of experiments including ablation studies to evaluate the contribution of different components and design choices in our solution.

abstract: M.A.Sc.


title: Towards the Development of Cost-Effective Decentralized Applications: An Investigation of Transaction Processing Times on the Ethereum Blockchain Platform

contributor:
Hassan, Ahmed
Computing

subject:
Transaction Processing Time
Smart Contracts
Ethereum
Blockchain
Machine Learning
Regression Model
Model Interpretation
Decentralized Applications (DApps)

abstract:
Ethereum is one of the most popular blockchain platforms for the development of blockchain-powered applications (i.e. ÐApps). When engineering ÐApps, developers need to translate requests captured in the frontend of their application into one or more smart contract transactions. These transactions target specific smart contract functions, and execute once the transactions are processed by other nodes in the network. Developers also need to pay for these transactions, and thus for their code to be executed. Generally the more a ÐApp developer pays for their transaction (i.e., the higher the gas price), the faster the transaction is likely to be processed.

In turn, developing cost-effective ÐApps is far from trivial, as developers need to optimize the balance between cost (transaction fees) and user experience (transaction processing times). Online services have been developed to provide ÐApp developers with an estimate of how long a transaction will take to be processed given a certain gas price. The accuracy of these estimation services are crucial in the Ethereum domain. However, despite their key role, the accuracy of such services has not been empirically investigated so far. Additionally, the platforms do not disclose any information regarding their models, particularly information about the used and most important features in the predictions of these models. These issues make it difficult for ÐApp developers to fully trust the predictions generated by such platforms, and also prevents them from being able to forecast variations of gas prices in the future.

In this thesis, we study the transaction processing times in Ethereum, investigate the relationship between such processing times and gas prices, and determine the accuracy of state-of-the-practice estimation services. Next, we construct machine learning models using comprehensive sets of Ethereum-based features in order to determine the most important features by characterizing transaction processing times. From these results we can derive numerous implications in order to help ÐApp developers achieve adequate levels of QoS through means such as choices of gas prices for their application-issued transactions.

abstract: M.Sc.


title: Attentive Cross-Modal Connections for Learning Multimodal Representations from Wearable Signals for Affect Recognition

contributor:
Etemad, Ali
Hungler, Paul
Electrical and Computer Engineering

subject:
Multimodal
Representation Learning
Fusion
Affect Recognition
Wearable Signals
Emotion Recognition
Cognitive Load Assessment

abstract: We propose cross-modal attentive connections, a new dynamic and effective technique for multimodal representation learning from wearable data. Our solution can be integrated into any stage of the pipeline, i.e., after any convolutional layer or block, to create intermediate connections between individual streams responsible for processing each modality. Additionally, our method benefits from two properties. First, it can share information uni-directionally (from one modality to the other) or bi-directionally. Second, it can be integrated into multiple stages at the same time to further allow network gradients to be exchanged in several touch-points. We perform extensive experiments on three public multimodal wearable datasets, WESAD, SWELL-KW, and CASE, and demonstrate that our method can effectively regulate and share information between different modalities to learn better representations. Our experiments further demonstrate that once integrated into simple CNN-based multimodal solutions (2, 3, or 4 modalities), our method can result in superior or competitive performance to state-of-the-art and outperform a variety of baseline uni-modal and classical multimodal methods. Further, we explore the notion of 'cognitive load' classification to explore multimodal representation learning and our proposed solution in the field of affective computing but beyond `emotion recognition.’ To this end, given the lack of widely adopted datasets in this area, we introduce a new dataset called Cognitive Load Assessment in REaltime (CLARE), with which we evaluate our proposed method. In this dataset, we collect a number of wearable modalities from 24 participants. We use MATB-II to induce different levels of cognitive load in participants by changing the complexity of tasks during the experiment. Contrary to other datasets in this domain, we record the subjective cognitive load values in real-time at 10-second intervals during the experiment. We then show that our proposed solution results in effective multimodal representation learning, outperforming baseline uni-modal and classical multimodal methods (feature-level fusion and score-level fusion) in classifying cognitive load.

abstract: M.A.Sc.


title: "Our Kind of Love": Black and White Interracial Relationships in Nineteenth and Twentieth Century Ontario

contributor:
Dubinsky, Karen
History

subject:
Ontario
Interracial Relationships
History

abstract:
The subject of Black and White interracial relationships is one that has been neglected in the existing historiography of Black Canadian studies.  Historically, scholars have treated these relationships as salacious stories or as footnotes in larger historical narratives.  The omission of these relationships, which are present in the historical record, is perhaps best exemplified by the mythology surrounding the James Mink, his White wife Eliza, and the false story around their daughter Mary’s enslavement in the United States.  None of the story is true, yet scholars have included the tale in the body and footnotes of their works for over a century.  One such scholar was Daniel G. Hill, a Black man who was also married to a White woman, Donna Bender.

This thesis explores the subject of Black and White interracial relationships in the context of nineteenth and twentieth century Ontario through an examination of the Mink and Hill families.  While separated by over a century, these two partnerships are thematically linked by their experiences of interracial marriage, their connections to family, and the requisite negotiations of respectability in which both couples engaged.  They are also connected through the historiography, as Daniel G. Hill is one of the crucial mythmakers who perpetuated the false story about the Mink family.

I utilize the case studies found in the relationships of James and Eliza Mink and Daniel and Donna Hill as “historical snapshots”; this project does not claim to be indicative of all Black and White interracial relationships.  Rather, by examining the stories of these two families, how their lives were misrepresented, and how they themselves participated in the curation of history, my thesis demonstrates the influence of broad historical trends on individual family units.  I also argue that similar forces in Ontarian society- such as race, gender, or class- impacted the retelling of interracial narratives in academia and popular culture.

abstract: M.A.


title: Cognitive and Affective Control of Pain in the Human Brain and Brainstem Revealed by Means of Functional MRI and Analyses of Network Connectivity

contributor:
Stroman, Patrick
Neuroscience Studies

subject:
fMRI
Pain
Pain Regulation
Structural Equation Modeling
Network Connectivity
Central Nervous System
Cognitive and Affective Modulation

abstract: Pain is a complex individual experience that involves sensory/discriminative, motor, autonomic, and cognitive/affective components. Acute pain permeates the human experience, and chronic pain is highly prevalent and costly within our healthcare system. Despite centuries of characterization and research, we have not yet precisely described the neurophysiological mechanisms of pain processing and modulation. The objective of the work contained in this thesis was to further our understanding of the complex temporal relationships and interconnected functions between brain and brainstem regions during the experience of pain and in other sensory or modulated states. Each of three projects employed functional MRI methods to explore related aspects of the sensory, cognitive, and affective dimensions of pain perception and regulation in healthy volunteers. The first study investigated properties of affective pain modulation using previously collected data from music analgesia, mood modulation, and individual differences studies. This work provided a foundational understanding of the powerful effects that cognitive and affective strategies, as well as autonomic homeostatic influence, can exert to continuously alter the way that we experience acute pain. The second study built on this foundation by expanding our connectivity network into cortical regions and limbic structures in order to assess the effects of music analgesia in greater detail. The results of these two studies provided complementary evidence for the complex nature of continuous, active pain modulation, and the influence of our psychological state in engaging the descending modulatory feedback system. The last study aimed to simplify the approach to focus on the sensory/discriminative domain of pain, comparing neural activity across painful and non-painful somatosensory stimuli. Surprisingly, the results showed no group differences in connectivity between stimuli, but individual differences were found based on pain sensitivity and regions associated with cognitive and affective processing. Together, this body of work supports the assertion that healthy pain responses are dependent on our psychological and homeostatic states, which continuously adapt to our environment and provide feedback to neural systems that process sensory integration.

abstract: PhD


title: The Performance of HDPE Geomembrane Fusion and Bituminous Geomembrane Seams

contributor:
Rowe, R. Kerry
Civil Engineering

subject:
Geosynthetics
Geomembrane
Seams
Welds
Quality Assurance

abstract: The properties of geomembrane (GMB) sheet material and seams are critical factors controlling the design life of a constructed barrier system. In particular, the resistance to stress cracking and retention of antioxidants in the GMB are critical factors to both the short and long-term performance. Thus, stress crack resistance (SCR) and standard oxidative induction time (Std-OIT) test were performed on both the sheet and fusion seams. SCR experiments on high density polyethylene (HDPE) GMB seams found that the exclusion of a predetermined defect (i.e., a notch) allowed the GMB seam to fail preferentially where it would in the field, in addition to providing failure times that included the seam heat-affected zone (HAZ) within the crack initiation region of the test specimen. Seam squeeze-out geometry and the presence of discontinuities within the squeeze-out bead were found to influence unaged seam SCR, with discontinuities running parallel to the direction of the seam creating lower seam SCR values on average. Seam squeezeout is shown to be susceptible to Std-OIT loss, with some seams showing near complete antioxidant depletion for specific welding parameter combinations. Seam thickness reduction was found to correlate with the degree of antioxidant depletion within a seams squeeze-out bead, with thickness reductions greater than 0.6mm for a 1.5mm HDPE geomembrane generally coinciding with significant antioxidant depletion. Adherence of seam squeeze-out to the GMB seam’s HAZ resulted in faster time to nominal failure (tNF) compared to the unnotched sheet material, with three seams exhibiting squeeze-out adherence having a tNF ~21-35% faster than that of the sheet material, while seams without adhered squeeze-out beads showed a tNF similar to that of the unnotched sheet following immersion tests at 85°C in a synthetic leachate solution. The short-term tensile shear strength and constant tensile load failure times of bituminous geomembrane (BGM) seams are also examined. Tensile shear specimens experienced failure in the sheet material when seams strength was >0.8 times that of the sheet, while all constant tensile load specimens experienced failure within the seam. The presence of geotextile engagement is hypothesized to significantly increase a BGM seams performance when subject to constant tensile loads.

abstract: PhD


title: Service Provisioning at the Network Edge - A VNF-Sharing Approach

contributor:
Hassanein, Hossam
Computing

subject:
Edge Computing
SFC
NFV

abstract:
The next generation of mobile networks (5G) is expected to address the performance requirements of various use cases in different industries, including ultra-reliable low latency communication (URLLC). The demand for URLLC requirements is fueled by the growing popularity of real-time media, delay-sensitive, and time-critical applications. Most services consist of virtual network functions (VNFs) stitched together in a specific order that form service function chains (SFCs). Premium SFCs
are time-critical, and their failure (pre- or post-deployment) could result in Quality of Experience (QoE) degradation. Best-effort SFCs are prone to delay, and can tolerate waiting for resource availability.
Edge computing is positioned to fulfill the aforementioned stringent latency requirements. Due to edge limited resources, the tendency to reject service requests -including time-critical ones- can be high, translating into unsatisfied customers, lost
revenue for service providers, and even safety hazards. Yet, existing work on the provisioning of SFCs at the edge make unrealistic assumptions. Such assumptions include: the edge has an abundance of resources; and SFCs have the same priority.
In this thesis, to improve the utilization of the service provider’s limited edge resources and reduce the cost of service provisioning, we introduce the sharing of VNFs among different SFCs. Taking advantage of operations dynamics, VNF sharing utilizes the unused capacity of deployed VNFs before instantiating new ones when satisfying new SFC requests. Specifically: 1) Using VNF sharing, the system utilization is enhanced by satisfying more SFC requests and using fewer resources per request. 2) SFC placement schemes that prioritize premium over best-effort services are introduced.
3) Prediction- and preemption-based placement schemes for time-critical SFCs are proposed to mitigate the consequences of SFCs rejections.
Extensive simulations demonstrate the effectiveness of VNF sharing-based schemes in achieving significant improvements to system utilization and reducing the rate of rejection of premium SFCs. The results indicate that VNF sharing helps service
providers lower the service provisioning cost while respecting the stringent delay budget of time-critical applications and services.

abstract: PhD


title: On The Yield and Fracture of Cast A205

contributor:
Diak, Bradley
Pilkey, Keith
Mechanical and Materials Engineering

subject:
metal matrix composite
digital image correlation
SEM-DIC
cast
aluminum
aluminium
yield
fracture
tib2
Al-Cu-Mg-Ag
A205
particulate
age-hardenable
mechanical testing
structure-property relationship
yield strength
Failure
intergranular
Damage
Strengthening mechanisms
FIB-SEM
3D Reconstruction
Microstructure
FIB 3D Reconstruction
X-ray Tomography

abstract: A205 is an Al-Cu-Ag-Ti-Mg-TiB2 age-hardenable alloy developed to improve castability in long freezing range alloys and results in a unique two-region microstructure consisting of TiB2 rich intergranular regions (IGRs) and grain interiors. The present work uses traditional and three-dimensional characterization techniques, together with mechanical testing, digital image correlation, and damage and fracture analysis to advance the understanding of the structure-property relationships of A205 under simple stress states. The IGRs contain a 17-19% local volume fraction of TiB2 particles and Cu-rich particles, the latter of which do not completely dissolve after a solutionizing treatment. Furthermore, the hardness response after ageing is reduced in these regions. The added TiB2 does not appear to contribute meaningfully to yield strength and precipitation remains the main strengthening agent in A205 like traditional age-hardenable aluminum alloys, contributing on average 265.5 MPa to the 0.2% offset yield strength from the as-quenched to the 13-hour aged state. Over the same ageing conditions, the plastic strain to failure decreases from approximately 14% to 1.5-3%. Digital image correlation through scanning electron microscopy reveals highly heterogeneous plasticity, with strain localization between the grain interior and the IGRs, and between particles within IGRs. Effective shear strains exceeding 15% occur between particles in the IGR in the 13-hour aged state at an average strain of approximately 3.5%. Damage observations reveal that almost all damage events occur within the IGRs, regardless of material condition. Particle cracking, particle-matrix decohesion, and matrix cracking in particle clusters are observed together with local coalescence. Such events are first observed on the surface at an applied stress of approximately 300-350 MPa regardless of condition. Damage growth occurs until blunted by the grain interiors. Cracks on the order of the grain size form and trigger catastrophic failure at a critical stress dictated by the local K1C of the IGRs, typically between 450-500 MPa. Such an applied stress is attained at far lower strain in the stronger aged states. Fracture surface observations reveal ductile dimpled fracture involving the IGRs.

abstract: M.A.Sc.


title: Impact of Carbapenemase Mechanism on the Clinical Detection of Carbapenem-Resistant Bacteria

contributor:
Lohans, Christopher
Allingham, John
Biomedical and Molecular Sciences

subject:
Antibiotic Resistance
Class D Carbapenemases
β-lactams
Clinical Detection
Surface Enhanced Raman Spectroscopy

abstract:
Production of β-lactamases by multidrug-resistant bacteria is one of the most common mechanisms of antibiotic resistance. A subclass of β-lactamases called carbapenemases threaten the clinical viability of carbapenems, a group of antibiotics used as last-resort therapeutics. Rapid detection of carbapenemase-producing bacteria is critical when determining the appropriate therapeutic to treat an infection. Serine β-lactamases with carbapenemase activity employ a two- step mechanism that involves the formation of an acyl-enzyme intermediate, which then gets hydrolyzed by a nucleophilic water molecule, ultimately rendering the antibiotic inactive. As carbapenem hydrolysis results in a decrease in pH, many current detection approaches use colorimetric pH indicators to monitor carbapenem degradation. However, although carbapenem- hydrolyzing class D β-lactamases (CHDLs) are becoming of increasing clinical significance, they are substantially more difficult to detect through pH assays when compared to other carbapenemases.
We recently found that CHDLs can degrade carbapenems through an alternative mechanism involving the formation of carbapenem-derived β-lactones We hypothesize that this mechanism impacts the clinical detection of bacteria that produce these enzymes. To investigate whether lactone formation impacts the detection of CHDL-producing bacteria, we adapted a clinically used pH assay. In combination with NMR spectroscopic studies, our assay results indicate that carbapenem degradation through β-lactone formation results in a smaller change in pH than hydrolysis. In addition, we have shown that conservative substitutions in the active sites of CHDLs have a dramatic impact on the relative levels of β-lactone and hydrolysis products formed. The V120L variant of the CHDL OXA-48 catalyzes carbapenem degradation almost exclusively through lactone formation, with little impact on pH; notably, this enzyme has been identified in a clinical context. As our results demonstrated that clinically used pH assays have significant limitations in detecting CHDLs, we have also been exploring alternatives like surface enhanced Raman spectroscopy (SERS). Our results reveal that CHDL-producing bacteria are likely missed by current pH-based detection strategies due to the mechanism by which the CHDLs degrade carbapenems.

abstract: M.Sc.


title: PROMOTING EVIDENCE-BASED ASTHMA DIAGNOSIS AND SURVEILLANCE USING ELECTRONIC TOOLS

contributor:
Lougheed, M. Diane
Translational Medicine

rights: Attribution-NonCommercial-NoDerivs 3.0 United States

subject:
Asthma
Electronic medical records
Quality improvement
Knowledge translation

abstract:
Background: In Canada, asthma is one of the most common chronic conditions. It is estimated that approximately 3.8 million people in Canada suffer from asthma. The majority of asthma diagnoses and care take place in primary care settings. Electronic tools (eTools) offer an opportunity to utilize technology to improve asthma diagnosis and surveillance.
Purpose: The purpose of this study was to create and validate a case definition or separate case definitions for suspected and confirmed asthma in primary care electronic medical records (EMRs) for use in eTools and to understand how to develop and scale a primary care surveillance system for quality improvement of asthma diagnosis and care.
Methods: A respirologist, family physician, and trainee manually classified 776 adult patient charts from a primary care practice EMR in Kingston, Ontario as suspected asthma, confirmed asthma, or not asthma using Canadian Thoracic Society criteria. Case definitions based on billing codes, clinical data elements and medications were applied to the site’s Canadian Primary Care Sentinel Surveillance Network (CPCSSN) data for the same charts and compared to abstractor classifications to determine each case definition’s measurement properties. Opportunities and barriers to developing and scaling eTools for asthma were determined through two focus groups using a mixed-methods approach.
Results: The prevalence of suspected and confirmed asthma were 7.3% (n=54) and 2.4% (n=18) respectively in this study. Case definitions based on this EMR dataset could not distinguish between suspected and confirmed asthma. One case definition consisting of billing, clinical, and medication elements had the best measurement properties for suspected or confirmed asthma with a sensitivity of 81%, specificity of 90%, positive predictive value of 45%, negative predictive value of 98%, and Youden’s Index of 0.71 for combined suspected or confirmed asthma cases. A total of 7 key themes important to the development of a surveillance tool were identified through mixed-methods analysis.
Conclusions: An EMR case definition for suspected or confirmed adult asthma has been validated for use in a CPCSSN database. Implementation of this case definition in conjunction with developing new eTools that address the key themes identified in this study will enable the development of a primary care surveillance system for quality improvement in adult asthma care. Adoption of EMR data elements that document asthma diagnosis status is warranted and would greatly enhance such a system

abstract: M.Sc.


title: “You Appear Silent to People Who Are Deaf to What You Say”: Solidarity, Schisms, and Alterity in Immigrant Women’s Political Organizing in Toronto, 1970s-1990s

subject:
immigrant women
history of feminism
social movements
race
gender
class
reproductive justice
labour history
Toronto
postwar Canadian history
women of colour

abstract: This thesis considers the connections between the increased migration of racialized women to Canada and the ascendancy of social movements in Toronto from the 1970s to the 1990s. In the mid-1970s, there was a surge of grassroots organizations founded by and for immigrant women in Toronto. They were established to address the distinct needs and experiences of immigrant women where government and preexisting, decidedly hypermasculine, ethnocultural organizations did not. This thesis argues that these organizations, and the individuals associated with them, were fundamentally political. In situating these organizations within the broader progressive political landscape of Toronto, this thesis elucidates the ways in which immigrant women’s political organizing challenged and transformed dominant social movements. In particular, immigrant women’s fraught relationship to the mainstream women’s movement in Toronto is closely examined. I argue that immigrant women organized both within and without the Toronto women’s movement. In their relationship to the women’s movement, immigrant women contested the limited perspective of white feminism by drawing closer attention to class and race. This was most evident within immigrant women’s organizing for reproductive freedom. Additionally, immigrant women organizer’s relationship to the Canadian state is analyzed as a site of struggle which dialectically constrained and sustained their activism. Because immigrant women worked in higher numbers than their Canadian counterparts and often in exploitative sectors, labour became a central issue within their activism. Through their labour organizing, immigrant women forged important alliances with the labour movement. This thesis also attends to the uneven racialization of immigrant women which informed their activism. Immigrant women’s activism offered alternative perspectives and methods of organizing which did not conform to dominant ones. By taking a relational rather than assimilationist or pluralistic approach to the relationship between immigrant women’s organizing and broader social movements, a fuller, more nuanced portrait of the intersections between immigration, gender, race, and social movements can emerge.

abstract: M.A.


title: Enriching User Experience for Human-Vehicle Interactions using E-textiles

contributor:
Nabil, Sara
Computing

subject:
Human-Vehicle Interaction
User Experience
E-textiles
Research through Design
Non-Driving Related Activities

abstract: Future vehicles are envisioned to enable much more functions than mere transportation, and---with the rise of automated vehicles---cars will be living spaces that support an array of non-driving related activities (NDRAs) beyond driving. While current research mostly focuses on user interaction with in-car systems to enhance usability, performance and functionality, we focus on enhancing the experience of users and the aspects of enjoying NDRAs by using e-textiles. This thesis introduces e-textiles to Human-Vehicle Interaction (HVI) design space to enrich user experience within car interiors. By analyzing and reviewing the current literature of HVI publications and survey papers, we contribute a literature-derived taxonomy for car interfaces and a roadmap of future trends in HVI through our three-generational approach. During this Research through Design (RtD) project, we have conducted an iterative design process, through which we fabricated an array of e-textile prototypes that detect direct user input through physical interaction. The final three prototypes designed for the user study were inspired by the recent literature and the automotive industry's contemporary design norms. These three prototypes were embedded in the steering wheel, headrest cover and seatbelt pad. To test and evaluate how drivers can interact with in-car interiors for NDRAs (such as media interaction) while on the road, we deployed our implemented designs in a vehicle and ran a user study with 16 participants to collect qualitative data through field observations and post-study interviews. Our findings show that, compared to screen-based interaction, participants preferred fabric-based user interfaces (UIs) more (indicating a practical alternative to screen-based interaction for NDRAs), enjoyed a richer user experience, had fewer crashes with the car, focused more and took their eyes away from the road less, supported by our preliminary quantitative analysis. Moreover, based on their comments, many design opportunities were derived, including new gestures and locations where e-textiles could be deployed, enhancing other research works and designing e-textiles for takeover situations. However, to allow these design opportunities to be explored further and realized, at first, barriers and challenges in designing e-textile sensors and NDRAs in both manually-driven and automated cars have to be mitigated or addressed.

abstract: M.Sc.


title: Development of Bioluminescent Biosensors Monitoring Activity of the Merlin Tumour Suppressor

contributor:
Yang, Xiaolong
Pathology and Molecular Medicine

subject:
Biosensor
Complementation Assay
Hippo Pathway
LATS
Luciferase
Merlin
NanoBiT
NanoLuc

abstract: All solid tumours share the ability to circumvent or overcome contact inhibition of proliferation (CIP), the process by which cell-cell contacts engage signalling to stop proliferation. Merlin, an ERM-like protein, plays a crucial role in CIP and is inactivated in a wide variety of cancers, suggesting that it is a tumour suppressor of general importance in cancer biology. Although the role of Merlin in cancer has been investigated extensively, this protein lacks intrinsic catalytic activity and has been notoriously difficult to study. To address this issue, we leverage novel luciferase technologies to develop and validate 2 split-luciferase biosensor systems that enable accurate quantification of Merlin activity in real time. First, we design an intramolecular biosensor aimed at studying Merlin’s changes in conformation state. In addition, we design a bimolecular split-luciferase system to investigate Merlin’s regulation of the Hippo pathway, a key downstream effector with well-established roles in cancer biology. Ultimately, these biosensors enable improved study of Merlin’s molecular functions, serving as powerful tools to investigate Merlin’s contributions to CIP and tumorigenesis.

abstract: M.Sc.


title: Effect of Systemic Versus Localized Bacillus Calmette-Guérin Immunotherapy on Bladder Cancer Progression: Novel Role for Trained Immunity

contributor:
Graham, Charles H
Biomedical and Molecular Sciences

subject:
Cancer Immunology
Bladder Cancer
Systemic Immunity
Trained Immunity
Bacillus Calmette-Guerin

abstract: The standard of care for high-risk non-muscle invasive bladder cancer (NMIBC) involves intravesical immunotherapy with Bacillus Calmette Guérin (BCG). Unfortunately, most patients do not respond fully to this therapy, and our understanding of the immunotherapeutic effect of BCG is incomplete. The tumor immune microenvironment (TiME) is known to influence responses to immunotherapy, and there is mounting evidence that the activation of a systemic immune response is critical for the induction of local anti-tumour responses. Based on this knowledge, we hypothesized that compared with the standard intravesical route, systemic intravenous administration of BCG will result in improved anti-tumour immune responses. Using a syngeneic orthotopic mouse model of NMIBC, here we show that bladder tumors from mice that received intravenous BCG treatment were smaller compared with those that received intravesical BCG treatment. This reduction in tumor size was associated with an increased proportion of CD8+ T cells, with a skew towards tumour-specific T cells, and a reduced proportion of inflammatory and patrolling monocytes in bladder tumors. Our results also indicate that, in the absence of a tumour, intravesical BCG treatment leads to increased proportion of neutrophils in the bladder, which have been associated with a tumour-permissive niche. Furthermore, we investigated the role of trained immunity, also known as innate immune memory, as a potential mechanism through which BCG-induced systemic immunity leads to local anti-tumour effects. Our study indicates that co-instillations of cancer cells and BCG-trained macrophages lead to a more cancer-specific CD8+ T cells phenotype compared with untrained macrophages. Together, our results demonstrate that systemic immunity is required for optimal anti-tumour responses and that BCG-induced trained immunity represents a potential mechanism by which systemic immunity induces local responses. Understanding the link between systemic immunity, trained immunity, and the TiME following BCG therapy may facilitate the development of new approaches to improve outcomes and reduce recurrence rates in patients with NMIBC.

abstract: M.Sc.


title: Understanding the Experiences of Frontline Workers in Long-Term Care During the COVID-19 Pandemic: A Narrative Study

contributor:
Camargo-Plazas, Pilar
Nursing

subject:
COVID-19
Coronavirus
Long-Term Care
Frontline Workers
Health Care Providers
Infectious Outbreak
Narrative Inquiry
Photovoice
Disaster Preparedness

abstract: In Canada, the COVID-19 pandemic has had devastating effects on the residents and staff in long-term care (LTC) facilities, yet little is known about the experiences of frontline workers in LTC facilities with infectious outbreaks. The need for specialized knowledge of experiential and subjective data is significant to help us improve our understanding of the effects of the pandemic on frontline workers, and to develop stronger practices and disaster preparedness in LTC settings. The purpose of this research was to gain a deeper understanding of the experience of frontline workers caring for residents in LTC homes during the COVID-19 outbreaks using narrative inquiry. Methods of data collection included interviews, photovoice, field notes, and a researcher’s journal. Participants captured photographs representing their experience working during the COVID-19 outbreak at their LTC home. Participants’ stories were collected in interviews through reflection on each of their photographs. Data analysis followed Frank’s hermeneutic method of analysis of stories. Data was explored for analytic interests that resonate through the multiple narratives; these included: psychosocial effects, support, loss of normalcy, increased workload, and altruism and dedication. This study demonstrates the importance of equipping frontline workers with relevant knowledge to feel prepared and confident in protecting the residents, themselves, and their families. It highlighted the importance of protecting the mental health of frontline workers and the influence support from management personnel has on the experience of frontline workers during infectious outbreaks. This study demonstrates the role that disaster preparedness and policy development can have in the wake of infectious outbreaks. This study gave the frontline workers in LTC homes an avenue to share their experiences and provide firsthand insight into the events that took place during the COVID-19 outbreaks in LTC homes.

abstract: MNSc.


title: Applications of Liquid Repellent Surfaces and Patterned Wettability for Microfluidics and LC-MS

contributor:
Oleschuk, Richard
Chemistry

subject:
Microfluidics
LC-MS
Fractionation
Superhydrophobic surfaces
Slippery Liquid Infused Porous Surfaces

abstract:
Microfluidic devices make heavy use of liquid repellent surfaces in a variety of different manners. Digital microfluidics uses liquid repellent surfaces to ensure that sample droplets do not inadvertently adhere to the device and that analyte is not lost to adsorption. Superhydrophobic surfaces are a popular choice for such a purpose but are unable to repel organic solvents due to their low surface tension. This thesis explores the potential of the omniphobic Slippery Liquid Infused Porous Surface (SLIPS) as a replacement for superhydrophobic surfaces in digital microfluidics. A SLIPS was incorporated into a magnetically actuated digital microfluidic device, and the parameters for successful actuation of droplets on the device were thoroughly investigated. In addition, a series of demonstrative applications were conducted with the device. Two liquid-liquid extractions were performed using the SLIPS-based device. The first: a simple extraction of an organic dye to determine its partition coefficient (logP). The second: a more complex extraction of natural products from the media of a bacterial culture, followed by mass spectral analysis to confirm the successful extraction of natural products. In addition, the synthesis of nylon 6,6 was performed on the device, with successful synthesis verified with mass spectrometry. Our experiments demonstrated the ability to perform synthetic reactions as well as chemical analysis using digital microfluidic devices equipped with omniphobic surfaces.
Liquid repellent surfaces are also used in sessile droplet microfluidics, where they are used to generate regions of patterned wettability and surface energy traps (SETs). This thesis explored a potential application of patterned wettability, in the design and construction of a micro-fractionation device for LC-MS. The high density of the SET array allows for a much greater number of micro-fractions to be stored than in a well-plate or tray of vials. The micro-fractions can then be stored or transported before being analyzed via the liquid micro-junction surface sampling probe (LMJ-SSP). We found that target shaped SETs 2.5mm in diameter spaced 1mm apart were ideal for a flow rate of 500μL/min, although the optimal SET parameters are expected to increase and decrease in accordance with the LC flow rate. A model separation of caffeine and phenacetin was archived using the micro-fractionator, with individual fractions each spanning 0.36s of separation time. Mass spectral analysis of the archived separation was performed using the LMJ-SSP, and the chromatogram reconstructed from mass spectral data over 24 hours after the separation was performed. The success of this experiment demonstrated the ability to store LC separations on a chip and analyze them at a later date, which allows LC-MS experiments to be performed asynchronously, providing increased flexibility in analytical chemistry workflows.

abstract: M.Sc.


title: Interpersonal and Affect-Related Outcomes of Short-Term Targeted Loving-Kindness Meditation for Female Undergraduate Students

contributor:
Flores, Luis Jr
Psychology

subject:
Loving-Kindness
Meditation
Interpersonal
Affect
Anhedonic Depressivity
Other-Inclusive Self-Concept
Undergraduate
Women

abstract: Loving-kindness meditation (LKM), derived from a Buddhist practice focused on cultivating feelings of love towards others, has recently been found to be associated with immediate and long-term improvements in interpersonal and affect-related outcomes. Additionally, LKM can be targeted towards a particular individual to augment interpersonal outcomes specifically related to the targeted individual. As such, an LKM protocol targeting a close friend may be particularly beneficial for individuals in emerging adulthood, for whom close friendships serve an important function in identity formation and the fulfilment of intimacy needs. The aims of the current study were as follows: 1) to examine the interpersonal outcomes for short-term targeted LKM in female undergraduate students; 2) to investigate the affect-related outcomes of short-term targeted LKM in female undergraduate students; and 3) to conduct an exploratory mediation model investigating mechanisms of change for LKM. In the current study, 168 female undergraduate students completed baseline and follow-up questionnaires assessing interpersonal outcomes (i.e., other-inclusive self-concept, willingness to sacrifice, and interaction quality) and affect-related outcomes (i.e., positive affect, negative affect, anhedonic depressivity, and anxious arousal), separated by an intervening week of meditation practice targeting a close friend chosen at baseline; participants were randomly assigned to receive daily audio recordings of either LKM instructions (experimental condition) or neutral visualization instructions (control condition). Results indicated that: LKM was associated with increases in other-inclusive self-concept; LKM may protect against decreases in interaction quality associated with stress and isolation; and LKM is associated with decreased anhedonic depressivity. Further, an exploratory mediation model (controlling for baseline values) suggests that the relationship between LKM and decreased anhedonic depressivity is mediated by increases in other-inclusive self-concept. As such, an online distribution of short-term targeted LKM may be a low-cost and effective tool for improving social relationships and depressivity in emerging adults.

abstract: M.Sc.


title: Innate Immune Memory-Mediated Enhancement of Adaptive Immune Activation

contributor:
Graham, Charles
Biomedical and Molecular Sciences

subject:
Trained Immunity
Antigen presenting cells
Bladder cancer
Bacillus Calmette Guérin
Cytotoxic T Lymphocytes
Adaptive Immunity
Coronavirus

abstract: Innate immune memory, or trained immunity (TI), is a heterologous form of memory acquired by innate immune cells that confers non-specific immune protection. However, it has not yet been linked to enhancement of adaptive immune activation. Here, we investigated the role of Bacillus Calmette Guérin (BCG)-mediated TI acquisition on antigen presenting cell (APC) function and adaptive immune activation, both ex vivo and in murine models of non-muscle invasive bladder cancer (NMIBC) and coronavirus infection with murine hepatitis virus-1 (MHV-1), a murine coronavirus. BCG-trained dendritic cells (DCs) exhibited significantly increased ovalbumin (OVA) uptake and cross-presentation in vitro. Furthermore, naïve cytotoxic T lymphocytes (CTLs) co-cultured with trained DCs exhibit significantly increased proliferation and expansion. To compare local and systemic immune activation on anti-tumour responses in non-muscle invasive bladder cancer (NMIBC), a syngeneic orthotopic bladder tumour murine model was used, wherein female C57Bl/6 mice were instilled with MB49 bladder cancer cells directly in the bladder followed by intravesical BCG (the standard immunotherapy of bladder cancer) or intravenous (IV) BCG administration to directly activate systemic responses. IV BCG treatment led to significantly reduced tumour burden, measured by ultrasound, and anti-tumour tumour draining lymph node and bone marrow microenvironments, analyzed using polychromatic flow cytometry. IV BCG treatment also led to a heightened tumour-specific B and cytotoxic T lymphocyte (CTL) response in the spleen. To determine if these effects are mediated by TI, mice were co-instilled with MB49 cells and BCG-trained bone marrow derived macrophages, and increased tumour-specific CTLs were present in the tumour microenvironment. Finally, to determine the effect of BCG on coronavirus infection, trained alveolar macrophages (AMs) and monocytes were co-cultured with coronavirus-infected fibroblasts and reduced viral titer was observed in the supernatant. In vivo, mice injected intraperitoneally with BCG displayed reduced viral load in the lungs following coronavirus infection with murine hepatitis virus-1. These results provide evidence that TI enhances APC function, leading to improved adaptive immune activation. Elucidating ways to enhance adaptive immune responses through non-specific treatments, such as BCG vaccination, may help reduce future disease burden.

abstract: M.Sc.


title: TRACKED 3D ULTRASOUND NAVIGATED LIVER BIOPSY PROCEDURE WITH REGISTERED TOMOGRAPHIC SCANS

contributor:
Fichtinger, Gabor
Ungi, Tamas
Computing

subject:
Biomedical Computing
Computer Assisted Surgery
3D Ultrasound
3D Slicer
Liver Biopsy

abstract:
Purpose: When lumps are found in the liver a liver biopsy is commonly used to help diagnose and identify the lumps. A 2D ultrasound is often used to guide such a procedure as ultrasound guidance has been shown to improve the accuracy and outcome. Unfortunately, using a 2D ultrasound to guide a biopsy needle is difficult as it can be challenging to keep the needle in the single plane of the 2D ultrasound. By using a 3D ultrasound instead this issue can be eliminated as a volume is imaged instead of a singular plane. To integrate a tracked 3D ultrasound into a liver biopsy procedure, certain criterion must be met: navigation accuracy must be sufficient for surgical use, intra-operative time must not be greatly increased, and additions to the workflow must be easy to use by the operator. The objective of this research project is to design a 3D ultrasound-guided liver biopsy workflow and software, that can be reliably used by researchers in experiments on phantoms or patients under institutional ethics.
Methods: A workflow that allows for a 3D ultrasound-guided liver biopsy with the integration of pre-procedure scans was created by splitting the workflow into two treatments. A custom software was developed to allow for the easy completion of all tasks in the workflow in a streamlined form. The workflow and software were tested and validated on established test data and recorded phantom data. All calibration and registration results were then compared to ensure accuracy. The software was evaluated to ensure that it included all necessary functions for the designed workflow.
Results: The average FRE error for calibrating the 3D ultrasound probe was 1.1(± 0.1) mm with an average error between the calibrations of 1.0 (± 0.4) mm. The average FRE error of the three CT registrations was 0.9 mm with a target registration error of 13.2 mm for the one verified test set. The developed software system has shown to meet the needs for the intended protocol based on the proof-of-concept testing conducted.
Conclusion: In conclusion, this study has created a prototype software which effectively enables the use of a 3D ultrasound to guide a liver biopsy procedure. This was shown from the results of the various tests conducted on the workflow and software. The software shows promise for use in this application by researchers under institutional ethics, however it could benefit from additional testing and workflow changes to ensure that the TRE of the CT registration remain robustly within acceptable ranges.

abstract: M.Sc.


title: Essays on Auctions in Financial Markets

contributor:
Clark, Robert
Economics

subject:
Industrial Organization
Auctions

abstract:
This thesis studies the design of auctions used in financial markets. The first chapter studies the market for Credit Default Swaps (CDS), which are financial derivative products that insure bond investors against default. Determining their payout is complicated because the volume of insurance is larger than the debt outstanding and the value of a bond is heterogeneous. CDS payouts are set in a two-stage auction. In the first stage dealers commit to supply or purchase a fixed quantity at the unknown final price. Then, the excess supply or demand is announced and a multi-unit uniform price auction is held to clear the market. The paper develops and estimates a structural model of bidding in these auctions and uses it to explore the dynamic auction process and to consider counterfactual changes to a static double auction.

The second chapter proposes a computational method to solve for Bayes-Nash equilibria in games. It is applicable when the equilibrium can be characterized by a set of necessary conditions that link a distribution of private information (values) and actions (bids). The method allows for the solution of the multi-unit auction game with step-function bids that characterize, for example, electricity and Treasury auctions.  A set of simulations studies the performance of this solution method in (i) symmetric first price auctions and (ii) multi-unit auctions, and then the method is applied to evaluate a counterfactual uniform price auction for the Turkish Treasury.

The third chapter studies the scoring auction process used by the Federal Deposit Insurance Corporation (FDIC) to resolve insolvent banks. Although the basic structure of the scoring rule is known to bidders, they are uncertain about how the FDIC makes trade-offs between the different components. Uncertainty over the scoring rule motivates bidders to submit multiple bids for the same failed bank. To evaluate the effects of uncertainty and multiple bidding for FDIC costs we develop a methodology for analyzing multidimensional bidding environments where the auctioneer’s scoring weights are unknown to bidders, ex-ante. We estimate private valuations for failed banks and compute counter-factual experiments in which  scoring uncertainty is eliminated.

abstract: PhD


title: The Rhetoric and Reality of Class: The Narration of Working-Class Identity in China’s Early 1980s

contributor:
Hill, Emily
History

subject:
Egalitarianism
Class Discourse
Working-class Subjectivity
Industrial Workers
State-owned Enterprises

abstract: At the time of the founding of the People’s Republic of China (PRC) in 1949, egalitarianism was a key principle of the Chinese Communist Party (CCP), yet the goal of social equality has remained out of reach ever since. Before the death of Mao Zedong in 1976, the party-state responded with a political approach to industrial workers’ demands for economic equality. Officials organized class-centered political movements, distinguished “people” and “enemies” among workers, and shaped a new Chinese working class to match the goals of socialist state building. However, the party-state’s emphasis on class and class struggle did not survive into the post-Mao era of Reform and Opening. As economic development dominated the agenda of the new era, class discourse faded away from official propaganda, though without explicit disavowal of Maoist class struggle. Meanwhile, state sector workers experienced serious losses in economic benefits and political status, and new forms of inequality emerged in various social groups as economic reforms proceed. Therefore, China’s early 1980s (1979-1983) deserves investigation as a period of transition when the politics of class reflect continuity and departures from the Maoist era. Following the Marxist tradition of class analysis, this study adopts an approach combining macro-level analysis of historical changes and micro-level interpretation of workers’ daily lives. It examines the narration of class discourse and working-class subjectivity in China during the early 1980s. The thesis concludes that instead of applying the established Maoist political approach, in the early 1980s China’s party-state was willing to deal with inequalities within the economic sphere. This shift can be observed in the re-interpretation of class discourse and the transformation of state-owned enterprises. This research has also revealed discrepancies between the propaganda of class discourse and practices at the local level in China’s early 1980s. Although long-standing differentiating factors shaped in the Maoist era continued to influence the consciousness of industrial workers, workers in the early reform era were motivated more by economic elements than by political discourse.

abstract: M.A.


title: Using Microfluidics to Study the Behaviour of Magnetotactic Bacteria under Environmental Stressors

contributor:
Escobedo, Carlos
Chemical Engineering

subject:
Magnetotactic bacteria
Microfluidics
Environmental stressors
Bacterial stress response
Magnetotaxis

abstract:
This work presents an evaluation of Magnetotactic Bacteria’s (MTB) response to fluidic stressors. MTB have been previously proven to demonstrate great potential as carriers for therapeutic agents within the human body. Current research has found that MTB are able to survive in many environments and demonstrated their ability to travel through micro-vessels while under both flow and viscous stress. To investigate MTB survival in the human body, microfluidic platforms were used to model the environmental stressors the bacteria would encounter if introduced to the blood stream. While a range of responses from injury to stress were observed, the bacteria were able to maintain a level of motility compatible with their use in drug delivery. Three stressors were used in this study: sodium bicarbonate, sodium carbonate and citric acid.

The MTB responded differently to each stressor and concentration. High concentrations of sodium bicarbonate resulted in reduced speed but continued magnetotacitc ability indicating an injury response, introduction of sodium carbonate resulted in an increased speed and decreased magnetotactic ability indicating a stress response, and introduction of citric acid resulted in spikes of speed and consistent magnetotactic ability indicating a mixed stress and injury response. While the MTB exhibited an injury response in some conditions, they maintained motility and magnetotactic ability throughout the trials. The results of this study indicate that MTB have the necessary survivability required for introduction to the human body.

abstract: M.A.Sc.


title: Exploring the contribution of natural killer cell TGFβ signaling to pulmonary vascular development and the pathogenesis of hypoxia-induced pulmonary hypertension

contributor:
Ormiston, Mark
Translational Medicine

subject:
Bronchopulmonary Dysplasia
Pulmonary Arterial Hypertension
Natural Killer Cells
Immunology
Cardiovascular

abstract:
Background: Proper immune functioning is crucial for lung development and vascular stability; deviations to these processes may lead to complications, including bronchopulmonary dysplasia (BPD) and pulmonary arterial hypertension (PAH). BPD is a disease of prematurity that is characterized by underdeveloped distal airways and a truncated pulmonary circulation. It is associated with significant neonatal morbidity and mortality, as well as several respiratory complications later in life. PAH is a disease of obstructive vascular remodeling that is characterized by the cancer-like proliferation of pulmonary endothelial and vascular smooth muscle cells. This obstruction increases the pressure in the pulmonary vasculature, putting strain on the right heart, and leading to death in ~15% of cases each year. Both BPD and PAH are thought to be linked to immune dysfunction.  Natural killer (NK) cells are cytotoxic type I innate lymphoid cells that can promote vascular remodeling in both pregnancy and cancer in response to microenvironmental cues, such as hypoxia and transforming growth factor (TGF)-β.  Previous work has indicated that NK cells may have similar functions in the lung, supporting the suggestion that BPD and PAH may arise as a result of disruptions in the relationship between NK cells and the pulmonary endothelium. However, the precise contribution of NK cells to the pathogenesis of BPD and PAH and the molecular pathways governing their contribution have not yet been defined. This study explored the hypothesis that TGFβ signaling in NK cells is an essential contributor to normal vascular development in the lung and drives pathological pulmonary vascular remodeling in PAH.
Results: Studies used mice bearing a conditional deletion of Tgfbr2 in NK cells (Tgfbr2NK-/-). Tgfbr2NK-/- mice had a reduction of pre-capillary pulmonary arterioles relative to littermate controls, accompanied by a baseline increase in right ventricular (RV) systolic pressure in adult Tgfbr2NK-/- mice and the presentation of a BPD-like phenotype in Tgfbr2NK-/- pups by postnatal day 7. Despite this developmental defect, male, but not female Tgfbr2NK-/- mice exposed to chronic hypoxia were partially protected from developing pulmonary hypertension. We revealed elevated pSMAD2/3 and RV accumulation for hypoxic NK cells in male, but not female mice.
Conclusion: Our results identify NK TGFβ signaling as a critical contributor to pulmonary vascular remodeling in both development and disease, as well as a sex-specific role for NK cells in hypoxia-induced pulmonary vascular remodeling.

abstract: M.Sc.


title: Investigation of the Hydrogen Evolution Reaction and Hydrogen Oxidation Reaction on Nickel Single Crystal Electrodes in Alkaline Media

contributor:
Jerkiewicz, Gregory
Chemistry

subject:
Nickel
Electorchemistry
Single Crystals
Hydrogen Evolution Reaction
Hydrogen Oxidation Reaction
Electrocatalysis

abstract: Ni materials have become increasingly important with the push to develop renewable energy technologies, specifically water electrolysis and fuel cell technology. This is because Ni serves as a much cheaper alternative to commonly used noble metals such as platinum while still delivering strong catalytic activity and durability in alkaline media. As a result there have been several studies probing the fundamental interfacial electrochemical behaviour of polycrystalline Ni to further facilitate the development of these technologies. However, there are very few works involving the study of monocrystalline Ni electrodes, which are critical for the development  and understanding of nanoparticle materials used in water electrolysers and fuel cells. This work aims to address this gap in the literature by providing a systematic study of both the hydrogen evolution and oxidation reactions (HER & HOR) on Ni(111), Ni(100), and Ni(110) electrodes. To study the HER, the monocrystalline electrodes are first characterized through cyclic voltammetry (CV) measurements in 0.10 M aqueous NaOH solution saturated with N2 gas at a scan rate of 50 mV sec1. After characterizing the electrodes, the activity of the HER on the Ni(hkl) electrodes was analyzed by linear sweep voltammetry (LSV) measurements at a potential scan rate of s = 0.10 V s–1 ensuring steady-state conditions. Unlike polycrystalline Ni the constructed Tafel plots display two distinct linear regions, and the general trend for the electrochemical activity towards the HER of the Ni(hkl) electrodes was found to be Ni(111) > Ni(110) > Ni(100). To study the HOR the electrodes again had to be characterized by CV measurements in 0.10 M aqueous NaOH solution that was instead saturated with H2 gas. To determine the activity of the Ni(hkl) electrodes towards the HOR, linear sweep voltammetry (LSV) measurements were performed, and from them Tafel plots were constructed. The general trend determined for the Tafel slopes in the HOR region were as follows: Ni(110) > Ni(100) > Ni(111). After completing the LSV experiments further CV measurements were performed to characterize the Ni(hkl) electrode surfaces after a long exposure to oxidative conditions. It was determined that the long range order of the monocrystalline surface was affected by the oxidation and subsequent reduction that took place.

abstract: M.Sc.


title: High-dimensional Analyses of MicroRNAs in Lung Neuroendocrine Neoplasms

contributor:
Renwick, Neil
Pathology and Molecular Medicine

subject:
MicroRNA
Lung cancer
Lung neuroendocrine neoplasm
Machine learning

abstract: Lung neuroendocrine neoplasms (NENs) are a diverse group of enigmatic cancers. Lung NENs consist of two tumor families: carcinoids, consisting of tumor types typical carcinoids (TC) and atypical carcinoids (AC); and neuroendocrine carcinomas (NECs), consisting of small cell lung carcinomas (SCLC) and large cell neuroendocrine carcinomas (LCNEC). Due to their diverse biology and unspecific symptomatology, they are difficult to diagnose and whose molecular mechanisms are incompletely understood. MicroRNAs (miRNAs) are small, RNA molecules that post-transcriptionally regulate gene expression. They regulate many important pathways in cancers and are valuable biomarkers in many neoplastic diseases. To assess the diagnostic utility of miRNAs in lung NENs and evaluate their roles in regulation of lung NEN genetic pathways, we generated miRNA expression profiles from archived lung NEN tumor samples and representative lung NEN cell lines and investigated them using machine learning and data mining techniques. We first developed a novel feature selection algorithm that uses an ensemble method to identify discriminatory -omics biomarkers and used it to discover miRNA biomarkers of lung NENs. Finally, we compared lung NEN cell lines to non-NEN control lines to identify important miRNAs in lung neuroendocrine biology, and predicted their regulatory targets and their related pathways. Through these analyses we discovered two miRNAs which were able to discriminate carcinoids from NECs with high accuracy. We also identified two sets of three miRNAs as candidate markers for discriminating TC from AC, and SCLC from LCNEC, although these findings require further validation due to limited samples size. Finally, we found five miRNAs that regulate cell development pathways in lung NENs.

abstract: PhD


title: Automated Histological Labeling of Mass Spectrometry Imaging

contributor:
Ellis, Randy E
Computing

subject:
Histological annotations
Mass Spectrometry Imaging

abstract:
Registration of histological images to mass spectrometry imaging is a way to automatically align histological structure and metabolic function in a single coordinate frame. In a mass spectrometry image, each pixel is a mass spectrum; these pixels are difficult and laborious to manually label. The lack of labels is a challenge for conventional supervised learning: to date, mass spectrometry imaging data appear to use pixel labels generated entirely manually. We observed that histological images are annotated for regions of interest by board-certified pathologists. A minor challenge in computer vision is managing these annotation contours, which can be open contours, can have gaps, and can be overlapping.

In this work, we performed histological segmentation followed by a multi-step, multimodal contour registration. An algorithmic computer vision method was implemented to extract and fill annotation contours, creating a labeled mask for each annotation label. Histological labels were transformed to mass spectrometry coordinates using an inverse registration transformation. Closure and filling of annotation contours, and transformation of histological foreground tissue to mass spectrometry coordinates was successful for every sample across all tissue datasets. From our findings, this work can be used to automatically generate labels for mass spectrometry data from histological annotations.

abstract: M.Sc.


title: Soft-switched three-phase PV microinverter

contributor:
Jain, Praveen
Pahlevani, Majid
Electrical and Computer Engineering

rights: Attribution-NonCommercial 3.0 United States

subject: DC-DC converter, DC-AC inverter, DC-bus voltage controller

abstract:
This thesis presents novel soft-switching converter topologies for designing two-stage PV microinverters. The emphasis is placed on grid-tied, three-phase AC systems. Two-stage microinverter architecture comprises a DC-DC converter and a DC-AC inverter. This type of a microinverter provides maximum power point tracking (MPPT) and eliminates the use of short-life electrolytic capacitors. The two-stage power conversion, however, requires extremely high conversion efficiency from each stage.
A novel soft-switching DC-DC converter topology is first proposed. The proposed converter utilizes a standard phase-shift DC-DC converter, but with an additional resonant circuit that is used to regulate the input DC bus. The fundamental concept is to connect a variable-voltage source in series with the PV panel voltage to obtain a regulated DC voltage at the input of the DC-DC converter. In the proposed converter, frequency is used to regulate the input voltage and phase-shift angle to perform MPPT. A detailed analysis of the proposed converter has been carried out and necessary design equations developed. It has been shown in the thesis that the proposed converter topology results in low conduction and switching losses for all the active devices over the entire range of operation.
A novel soft-switching full-bridge DC-AC inverter is also proposed that provides ultra-low ripple output current. In the proposed inverter, the output filter network comprises a transformer, an inductor, and a capacitor. This inverter circuit utilizes the inherent current ripple cancellation property of the proposed circuit to inject ultra-low ripple grid current. It has been shown in the thesis that the proposed converter topology results in low switching loss for all the switches over the entire line-cycle and current level.
A composite non-linear feedback (CNF) based DC-bus voltage controller is proposed that exhibits a fast transient response for DC-AC inverters. Increased speed of the DC-bus voltage controller limits the fluctuations of the capacitor voltage from its set-point during transient conditions. This results in a lower value of DC-bus capacitance as compared to the conventional controller.
The concepts proposed in this thesis and their theoretical analyses are verified through circuit simulations and laboratory experiments.

abstract: PhD


title: Machine Learning for Time Series Anomaly Detection of Haul Truck Subsystems and Driver Behaviour

contributor:
Daneshmend, Laeeque
Mining Engineering

subject:
Mining
Haul truck
Machine learning

abstract:
This thesis investigates machine learning techniques for anomaly detection in the operation of ultra-class mining haul trucks. Data was collected from three different models of haul truck, and two data sets were created.
The first data set, focused on one of the three truck models, included the entirety of the 175 parameters accessible via the truck’s proprietary (OEM) monitoring system, sampled at 0.2 Hz, over some 11 hours of operation, and was gathered while several predefined truck maneuvers were performed. These maneuvers included aggressive (abrupt turns, large accelerations) and drowsy (slow veering, then sharp correction) driving behaviours. Subsystem anomaly detection on this first data set successfully applied Decision Tree and Random Forest Classifiers for detecting the anomaly labelled by the “High Brake Hydraulic Temperature” parameter but yielded poor performance detecting the anomaly labelled by the “Reduced Retard Level Switch” parameter.
The second data set was from an Inertial Measurement Unit (IMU) (3-axis accelerations and 3-axis rotations), recording truck dynamics for all three truck models during numerous maneuvers. Driver behaviour anomaly detection on the second set successfully applied 1-Nearest Neighbour Classifiers and Dynamic Time Warping in recognizing left and right aggressive and drowsy turns. Attempts at unsupervised classification with Agglomerative Clustering on this second data set yielded mixed results.
Overall, encouraging performance from this investigation indicates this is a fruitful area for further research on the detection of anomalies in mobile mining equipment.

abstract: M.A.Sc.


title: Comparing Mechanisms of Change in Group-Based Acceptance and Commitment Therapy to Cognitive Behavioural Therapy in Patients with Chronic Pain

contributor:
Tripp, Dean A.
Psychology

subject:
Chronic pain
Acceptance and commitment therapy
Cognitive behavioural therapy

abstract: Chronic pain is a costly, debilitating, and prevalent condition that requires biopsychosocial informed interventions for best management. This study aimed to compare acceptance and commitment therapy and cognitive behaviour therapy for chronic pain to determine whether they had differential effects on patient outcomes, on treatment process variables, and whether certain baseline ratings were related to outcomes over time. Chronic pain patients (N = 89) at a tertiary pain clinic were randomized to one of two eight-week therapy programs. Patients completed measures at the initial baseline assessment, after each therapy session, at post-treatment, and at a one-month follow-up appointment. Overall, ACT and CBT performed similarly in improving mental quality of life. Additionally, pain catastrophizing, psychological flexibility, and working alliance changed in both ACT and CBT. These findings suggest that ACT and CBT work through similar mechanisms, even if the mechanisms are not directly addressed in treatment. Baseline levels of psychological flexibility was associated with less pain-related disability, anxiety, depression, and improved physical quality of life indicating that patients with greater psychological flexibility as they enter treatment may benefit the most from psychological interventions. Ratings of neuropathic pain mediated the relationship between chronic pain acceptance and physical quality of life, suggesting that post-treatment neuropathic pain ratings explain some of the relationship between baseline chronic pain acceptance and physical quality of life one-month post-treatment. Additionally, higher levels of committed action at baseline were related to lower levels of anxiety at the end of treatment for only patients in the ACT group. Clinical implications and future research opportunities are discussed.

abstract: PhD


title: Software Ecosystem Sustainability, a Socio-Technical Perspective

contributor:
Adams, Bram
Computing

subject: Software ecosystem, Sustainability, Health, socio-technical, Mixed-method research

subject: Onboarding

subject: Release synchronization

subject: Micro-collaboration

subject: Cross-community feedback

subject: Phenomenology

abstract:
The last decade has seen a plethora of large-scale software ecosystems (SECOs) developed by distributed teams and organizations dispersed across the globe. Despite the growing success of these SECOs, many questions remain regarding their long-term sustainability, in particular in terms of what socio-technical activities during a SECO's lifecycle are beneficial. This thesis aims to empirically study SECOs' sustainability across four major SECO lifecycle phases, i.e., onboarding, micro-collaboration, release synchronization, and cross-community feedback mechanisms.

SECOs' onboarding process aims to recruit long-term, high-quality contributors. Through an observational study of an OpenStack onboarding event and mining repositories, we found a significant correlation of onboarding with increased gender diversity and patch acceptance rate, while the time until the first commit and bug-proneness of contributions decrease.

Second, we study the so-called micro-collaboration practices of distributed development, in which multiple authors contribute to the same commit (instead of to the same branch). To understand the mechanisms, benefits and limitations of micro-collaboration, we performed a mixed-method analysis of collaboration practices in the OpenStack ecosystem through semi-structured interviews and a mining repositories analysis.

Third, open-source SECOs bring value by integrating software projects into a polished product. However, since each SECO project may potentially have its own release cycle and roadmap, a SECO release team has to set up and enforce synchronization activities to sustain SECO releases. Qualitative analysis on OpenStack's release team's IRC-meeting logs allowed us to identify, catalogue, and document ten major release synchronization activities, which we further validated through interviews.

Lastly, SECOs continuously gather and process feedback from distributors, which customize a SECO product, and end users, for example in the form of bug reports and contributed features. We aimed to understand the effectiveness of these feedback mechanisms through a grounded theory study of unstructured interviews, a survey, focus groups, and mailing lists archives, leading to a theory involving 15 constructs. Validation of our theory using mining analyses suggests that distros contribute a substantial proportion of a SECO's feedback, and that influential distros in a SECO do not focus on one specific feedback type.

abstract: PhD