VictorJuiz/thesis huggingface dataset:
Incidence of New-onset Atrial Fibrillation following Transcatheter Closure of Patent Foramen Ovale in Ontario
Keywords: administrative health data
atrial fibrillation
health services research
machine learning
patent foramen ovale
survival analysis

Patent foramen ovale (PFO) has been associated with an increased risk of cryptogenic stroke. Transcatheter closure (TC) is a commonly recommended intervention for PFO for selected patients. Some recent evidence, however, has implicated TC with increasing the risk of new-onset atrial fibrillation (AF) post-closure. This thesis represents a comprehensive evaluation of the risk of AF following PFO closure. First, a systematic review and meta-analysis synthesized current evidence in the literature for new-onset AF in PFO patients following TC. Then, a random forest classification algorithm identified which patients underwent a PFO versus an atrial septal defect (ASD) closure in Ontario administrative database records. Lastly, identified PFO patients were evaluated for incidence of new-onset AF post-closure, which was relatively low. Diabetes and being over age 60 were predictors of post-closure AF in this population. Improvements in consistency of AF monitoring are needed to gauge the true risk of AF following TC.
Numerical Investigation On Flow Past A Backward Facing Step And Initial Study Of Synthetic Jets
Keywords: Backward Facing Step
Crossflow
Finite Span Synthetic Jets
Turbulence Modelling
URANS

The flow past a backward-facing step and the interaction of a synthetic jet with a duct cross-flow were investigated numerically using an incompressible RANS solver. The numerical result was able to predict the correct flow structure and velocity field for the backward-facing step. The synthetic jet actuator had a cylindrical cavity and the diaphragm movement was modelled physically accurate. The synthetic jet simulated was first validated with experimental data in quiescent flow, the jet velocity profile at peak phases were modelled correctly and net positive momentum was observed in the external region, while the actuator remained net-zero mass flux. The synthetic jet was then integrated into a duct to create a cross-flow, three different blowing ratios were simulated by adjusting the diaphragm vibration amplitude. The simulations allowed the formation of the synthetic jet to be analysed in a low Reynolds number cross-flow and demonstrated that URANS can be used to simulate synthetic-jet in both quiescent and cross-flow.
Development and Application of Laminar-specific Gene Expression Meta-analysis of the Human Neocortex
Keywords: Application
Brain
Laminar
Transcriptomics

Application of RNA sequencing (RNA-seq) has enabled the characterization of genome-wide gene expression in the human brain, including distinct layers of the neocortex. To advance our understanding of cortical architecture and layer-specific differences in gene expression, we performed a meta-analysis of multiple transcriptomic datasets of gene expression of varying techniques in neurotypical human brains. We observed differences in similarity between bulk-tissue and single-nuclei RNA-seq data, as well as layer-specific enrichment of gene expression. Using the techniques used for the meta-analysis, we developed a web application, LaminaRGeneVis, which allows users to perform similar analyses as performed here. Our results suggest that there is specific enrichment of genes that are relatively consistent across different types of data. These findings and the resulting application provide researchers a platform and reference point to better understand layer-specific gene expression in the human neocortex.
Urban Livelihoods and Flood Vulnerability in a State-Sponsored Resettlement Project in Iquitos, Peru
Keywords: Amazonia
environmental hazards
livelihoods
Peru
resettlement
vulnerability

In the Amazon floodplain, the annual flood cycle is an expected part of life; however, anthropogenic climate change is projected to increase the frequency and severity of floods. Further, poor urban residents in the Global South are often disproportionately exposed to floods. Resettlement is increasingly considered a potential climate adaptation policy for high-risk areas, but many past resettlements have failed to improve residents’ wellbeing. In Iquitos, Peru, the Peruvian government has set out to relocate 16,000 residents from Bajo Belén, a low-income neighborhood on the Amazon floodplain. Four hundred households have already relocated to a small settlement 15 km outside Iquitos. This research investigates how relocation changed residents’ livelihoods and vulnerability to floods, using household surveys and interviews conducted during fieldwork in 2019. Findings indicate that residents in Bajo Belén did not always perceive floods as risky, and that relocation has left residents isolated from services and opportunities.
AI in the Workplace: A Scoping Review of Knowledge, Skills and Abilities Required by Employees of the Future
Keywords: abilities
Artificial Intelligence
employees
knowledge
Skills
workplace

With the recent onset of Artificial Intelligence (AI) in the workplace, I ask how it will affect the knowledge, skills, and abilities (KSA) required by employees to work alongside the new technology. By conducting a rapid, scoping literature review in five most relevant databases I provide an original synthesis on the 168 articles. I find that trust in the new technology is an absolute requirement for employees, and this can be further fostered by ensuring that they have the relevant KSA to work along side AI. Additionally, I identify some of these relevant KSA for employees of the future, and the bring to light the imperative need to redesign roles and processes within organizations. Lastly, I provide a critical view regarding the evolution of AI in the workplace and its affect on the employee, recommending changes that will produce positive outcomes for all involved, especially the most vulnerable employees.
Approach-Avoidance Conflict Processing in Hippocampal Lesion and Aging Populations
Keywords: Aging
Approach-Avoidance
Decision-Making
Hippocampus
Lesions
Medial Temporal Lobe

Approach-avoidance conflict (AAC) occurs when an organism is simultaneously attracted to and repelled by a goal stimulus, as it cues concurrent possibilities of reward and punishment. A rich body of rodent literature has implicated the hippocampus (HPC) – a medial temporal lobe (MTL) structure traditionally associated with spatial navigation and memory – in AAC processing. These findings have culminated in a model of the hippocampus as exerting inhibitory control over behaviour in AAC scenarios (Gray McNaughton, 2000). Some human studies have provided converging evidence with the rodent literature, but there are comparatively few of them, and they have provided largely correlational evidence of the HPC’s involvement in AAC processing. Additionally, it is unclear whether AAC processing is a unique cognitive process or a special case of more general conflict. Similarly, there is some evidence that the HPC contributes to resolving AAC only with spatial/contextual stimuli (i.e., as opposed to object/item stimuli). The current study employed three versions of a behavioural paradigm designed to elicit AAC, using scene, object, and abstract stimuli, respectively. In a first experiment, we compared the behaviour of patient participants with circumscribed HPC lesions to that of healthy controls. Additionally, two response conflict tasks were administered to determine whether HPC-mediated behaviour differs in AAC and response conflict scenarios. Consistent with our hypotheses, we found that patients approached significantly more often than controls on AAC tasks with scene but not object stimuli. No group differences were observed on the response conflict tasks. We then conducted a second experiment with a modified version of the original AAC tasks, comparing the behaviour of young and older adults. Contrary to our hypotheses, no group differences were observed on either the AAC or the response conflict tasks. These findings and their implications for models of HPC involvement in AAC are discussed.
Patients’ Information use in an Online Health Community
Keywords: Covid 19
information use
knowledge creation
online health communities
patient support

Patients gravitate toward Online Health Communities when their healthcare professionals areunable to meet their needs. I conduct a discourse analysis using grounded theory to explore the information uses in a Facebook group with over 36,600 COVID-19 patients, survivors, and family members. To understand these information uses, I describe a Facebook Group as an information context, present the four types of contributors in the context, and unpack how the context influences information behaviours. I codify the posts into four themes, explain the information framing of these themes, and collect the respective conversations from the comments. To supplement my analysis, I engage with two moderators and integrate their insights into my analysis. There are few mechanisms for patients, as primary information sources, to relay their insights to medical professionals. My research explores how patients are capturing and sharing the unique knowledge they have about their conditions and the medical system.
Testing the Ensemble: Limitations in the Formation of Cross-modal Ensemble Representations of Taste from Vision
Keywords: cognitive psychology
ensemble coding
long term memory
perception
vision
visual working memory

Ensemble coding (the brain’s ability to rapidly extract summary statistics from groups of similar items) has been demonstrated across a range of visual features from low-level to high-level. Ensemble coding has also been demonstrated to operate on information that cannot be gleaned solely from retinal input and must be abstracted (e.g., object lifelikeness, object economic value). I extended this line of research to examine if different sensory modalities can interact during ensemble coding. Participants made judgements about the average sweetness of groups of different visually presented foods. Across three experiments, participants demonstrated the ability to form cross-modal ensemble percepts, albeit with some important limitations. Namely, participants were unable to incorporate all available information into their cross-modal ensemble percepts and utilized a subsampling strategy to make their judgements. Despite potential limits to our ensemble coding abilities, these studies do provide evidence that ensemble coding is more flexible than previously thought.
Measuring Multimorbidity, Classifying Potentially Inappropriate Medications and Investigating Polypharmacy in Recipients of Medication Reviews and Pharmacy Dispensing Services Conducted by Ontario Community Pharmacists
Keywords: community pharmacy
multimorbidity
pharmacist
polypharmacy
potentially inappropriate medications

Factors including aging and health related behaviours lead to multimorbidity, polypharmacy and potentially inappropriate medications (PIMs). Medication reviews conducted by community pharmacists can improve medication management. Patient data were extracted from three community pharmacies in Ontario. Multimorbidity scores and number of PIMs were determined. Construct validity was assessed via linear regressions with age and sex. Consistency among multimorbidity measures was assessed via Pearson correlation coefficients. The mean multimorbidity scores determined by disease counts, Charlson Index, Chronic Disease Score, Medication Based Disease Burden Index, and Rx-Risk measures were 4.9 (SD 2.3), 4.4 (SD 2.0), 7.1 (SD 3.6), 0.1 (SD 0.2), and 0.4 (SD 1.7) respectively. Most analyses supported construct validity and consistency among measures. Patients were taking a mean of 1.9 (SD 1.5) and 2.0 (SD 1.4) PIMs determined by the 2019 American Geriatrics Society Beers criteria and STOPP criteria respectively. The analyses can lead to the improved management of multimorbidity.
Investigating the Impact of Temperature and Oxygen on Preservation Injury after Ex vivo Kidney Perfusion
Keywords: Kidney Transplantation
Machine Perfusion
Organ regeneration

Kidney transplantation improves the lives of patients with end-stage kidney disease, and extends their life expectancy. Ex vivo machine perfusion has been extensively explored in past years for the storage and assessment of expanded criteria kidney grafts and donation after cardiac death grafts. Both normothermic and hypothermic machine perfusion techniques have benefits and shortcomings. In a porcine model, we found that grafts preserved with continuous and end-ischemic normothermic ex vivo machine perfusion (NEVKP) show better graft function demonstrated by lower peak serum creatinine and higher creatinine clearance than grafts preserved with hypothermic machine perfusion with and without oxygen. Moreover, we demonstrated that subnormothermic and normothermic machine perfusion result in comparable graft function after transplantation, even if metabolic function is reduced during subnormothermic perfusion. In a pilot clinical study, we evaluated graft and patient survival after end-ischemic NEVKP and could demonstrate the safety and feasibility of NEVKP for human deceased donor transplantation.
Optimization of Pin Fin Heat Sinks for High Power Density Electronics Using Genetic Algorithm Coupled with Computational Fluid Dynamic Modelling
Keywords: CFD
genetic algorithm
heat exchanger
thermo-fluid dynamic

The development of high-power electronic devices in various energy systems has recently gained attention for electric vehicles and hybrid electric vehicles. However, the increase in power density has also introduced several design challenges especially in thermal management. This thesis attempts to optimize a liquid cooled pin fin heat sink with localized heat sources representing an EV power driver using genetic algorithm (GA). Both pin geometry and pin locations are optimized to reduce thermal resistance and pressure drop of the coolant. Computational fluid dynamics (CFD) simulation is used in the genetic algorithm to evaluate the performance of each potential design during optimization. A set of optimizations with different geometric parameters has been carried out and compared. The results demonstrate that GA coupled with CFD may be a powerful tool for designing an effective and reliable heat sink for high power density applications.
Bayesian Preference Elicitation and Critiquing for Conversational Recommendation
Keywords: Conversational Recommendation
Recommender Systems

In the conversational recommendation setting, a user often has long-term preferences obtained from previous interactions along with temporary session-based preferences that need to be inferred through minimal interaction, either driven by the system~(i.e. preference elicitation) or by user~(i.e. critiquing). This thesis aims to extend the Bayesian paradigm of belief updating after each interaction for language-based conversational recommendation and focuses on addressing the following open problems: (1) existing Bayesian preference elicitation methods have typically focused on eliciting preferences in the space of items or small set of explicitly known objective attributes, and (2) existing methods for critiquing do not use Bayesian methods for managing uncertainty and rely on overly complex architectures that can perform poorly in practice.We empirically validate all contributions in comparison to non-Bayesian baselines and demonstrate the strong advantages of the novel methodologies proposed in this thesis.
“Our Families are Fearless”: Navigating, Resisting, and Building beyond Settler Colonial Demands for ‘Reasonableness’ at the Violent Intersections of Housing and Child Welfare Systems in Winnipeg’s North End
Keywords: Child Welfare
Housing
Indigenous Resistance
Parent Rights
Settler Colonialism
Winnipeg

While analysis of the relationship between housing and child welfare is limited in the Canadian academe, the same cannot be said of discussions on the ground: in North End Winnipeg, many Indigenous caregivers are acutely aware of the complex intersections between their housing quality and their ability to bring and/or keep their children home. Landlords, social workers and government officials are adamant that their respective institutions operate according to universally ‘reasonable’ rules – however, interviews with caregivers and a secondary analysis of non-profit tenant advocacy files reveal that each settler colonial system’s ‘reasonable’ demands frequently conflict and contradict to create fundamentally unreasonable expectations of parents. This research gathers together caregiver stories to map out the violent material and immaterial intersections of the child welfare and housing systems in intimate spaces of home, as well as how Indigenous caregivers strategically comply, resist, and build alternatives to keep their families housed and whole.
Power, Performance and Area Consequences of Multi-context Support in Coarse-grained Reconfigurable Arrays
Keywords: cgra
coarse-grained reconfigurable arrays
dynamic reconfiguration
multi-context
time multiplexing

Coarse-Grained Reconfigurable Arrays (CGRAs) are programmable logic devices comprising a two-dimensional array of large, often ALU-like, logic blocks, and datapath-style (multi-bit) programmable interconnect. A feature frequently associated with CGRAs is dynamic reconfigurability, wherein the CGRA supports multiple contexts. The multiple contexts form a set of configuration bitstreams that are loaded into the CGRA simultaneously and cycled through according to a schedule. Multi-context allows the CGRA hardware to be time-multiplexed: the logic blocks and interconnect can perform different functions according to the context selected in each clock cycle. In this thesis, we consider how multi-context may be implemented at the circuit level, and evaluate four circuit implementations from the power, performance, and area (PPA) perspectives. The PPA overhead of the multi-context feature in CGRAs vs. a single-context device is also quantified. We also explore context-switching using a State Transition Controller (STC), which can switch contexts without a fully predefined pattern.
Dual Existence: Performing the Bi-narrative Construction of University of Toronto’s International Students Studying from Home via Zoom
Keywords: Community
Covid-19
Dual existence
International Students
Storytelling

This paper recounts a qualitative research that employed storytelling as a research method to explore how University of Toronto international students who studied from outside Canada due to the Covid-19 travel restrictions construct their experience of space and time; form a community of support despite the divergence in their geographical, social, and cultural backgrounds; and respond with empathy to the one another’s stories. The project involved four participants from diverse nationalities and a range of issues that constitute their narration include language barrier; time difference; dual existence; and how they managed the challenges.
A Markov Process Approach to Untangling Intention Versus Execution in Tennis
Keywords: Markov processes
Execution error
OR in sports
Simulation
Tennis

Value functions are used in sports applications to determine the optimal action players should employ. However, most literature implicitly assumes that the player can perform the prescribed action with known and fixed probability of success. The effect of varying this probability or, equivalently, ``execution error'' in implementing an action, has received limited attention. We develop a novel modeling framework based on Markov processes to investigate how execution error impacts a player's value function and strategy in tennis. We power our models with hundreds of millions of simulated tennis shots. We find that optimal strategies become more conservative as execution error grows, and that having perfect execution with the empirical shot selection strategy is roughly equivalent to choosing one or two optimal shots with average execution error. We find that execution error on backhand shots is the costliest, and that optimal shot selection on a serve return is the most valuable.
Ontology Evolution as Ontology Reuse
Keywords: intended models
ontology design
ontology evolution
ontology versioning
reuse

Throughout the ontology lifecycle, different versions of an ontology are created, and the need for version management has been widely recognized. Although a number of definitions for ontology versioning have been proposed, several questions remain. How are different versions of an ontology related to each other? In what sense are they all versions of the same ontology? In this thesis we present an alternative characterization of ontology evolution as a form of ontology reuse. We propose a formal definition of ontology version with respect to the specification of the intended models of an ontology. We prove that this is equivalent to the formal definition of a reusable ontology. Based on this equivalence, we propose version operators and show how ontology evolution can be formalized through its application. Finally, in a case study of the Semantic Sensor Network Ontology, we leverage different techniques to assist in analyzing the feasibility of the application of the version operator.
Inventory Management using Reinforcement Learning
Keywords: Inventory Management
Monte Carlo Tree Search
Supply Chain Optimization

As a significant part of a supply chain, inventory management can involve predicting purchases from customers and controlling order fulfillment. In this thesis, we proposed a Monte Carlo Tree Search (MCTS) algorithm, combined with a local search optimization algorithm for search space reduction and a time series prediction model based on encoder-decoder structure and Bayesian optimization for demand forecasting to tackle an inventory allocation problem from Nestlé Canada, which is a sequential decision problem where we need to minimize the total monthly shortage of supply penalty charged by different companies by suggesting an optimized allocation plan every day with limited inventory on hand and unknown future orders. MCTS is a heuristic search algorithm that has been proved to be powerful in various decision processes, for example board games. In this thesis we introduced a variant of MCTS and showed that MCTS and reinforcement learning can also be effective in inventory management problems.
Reconfigurable Cylindrical Beamformers based on Electromagnetic Surfaces
Keywords: Azimuth
Cylindrical
MEFSS
metasurface
Reconfigurable

Communication networks involving data transfers between nodes both in the azimuth and elevation, such as military or search-and-rescue, require an antenna that can beamform and also beam scan. This thesis explores two reconfigurable cylindrical beamformers that can be used in these ad hoc networks. The first design presented is a reconfigurable 1-bit miniaturized frequency selective surface that switches between a reflecting and transmitting mode. The second is a continuously tunable metasurface that achieves both a reflecting and transmitting state along with over 180 deg of phase range in the transmit mode. The first design is fabricated and assembled into a cylindrical configuration. The antenna is shown to be able to both beamform and beam scan in the azimuth plane, between 4.9 GHz and 5.8 GHz.