VictorJuiz/thesis huggingface dataset:
Online Three-class Transcranial Doppler Ultrasound-based Brain Computer Interface

Transcranial Doppler ultrasound (TCD) is an imaging technique used to assess cerebral blood flow velocities (CBFV) and can be used to develop a brain computer interface (BCI). Generally in right-handed individuals, verbal cognitive tasks elicit a greater increase in CBFV in the left hemisphere in comparison to the right while spatial tasks result in greater blood flow to the right hemisphere. Previous TCD-BCI systems have used verbal and spatial tasks as control signals; however, the spatial task required a visual cue, which is not feasible for those with visual impairments and restricts the BCI to a system-paced paradigm. Therefore, new right-side lateralized tasks that do not require visual cues were investigated and evaluated as control signals in an online three-class TCD-BCI system. An average online accuracy of 62.4±10.8% (n=10) and information transfer rate of 1.08±0.69 bits/min was achieved. These results demonstrate the feasibility of a user-paced, vision-free, online TCD-BCI system.

Keywords: Brain computer interface
Lateralization
Transcranial Doppler ultrasound
Advisor: Chau, Tom
Guerguerian, Anne-Marie
Automatic Performance Tuning of Stencil Computations on Graphics Processing Units

The focus of this work is the automatic performance tuning of stencil computations on Graphics Processing Units (GPUs). A strategy is presented that uses machine learning to determine the best way to use the GPU memory followed by a heuristic that divides the remaining optimizations into groups and exhaustively explores one group at a time. The strategy is evaluated using 104 synthetically generated OpenCL stencil kernels on an Nvidia GTX Titan GPU. The strategy is assessed both in terms of the number of configurations explored during auto-tuning and the quality of the best configuration obtained. Two alternative heuristics that use different groupings of the optimizations are explored. Relative to a random sampling of the space and an expert search, the strategy achieves a reduction in the number of configurations explored of up to 71% and 84% respectively while finding configurations that perform 12% and 6% better respectively.

Keywords: auto-tuning
GPGPU
machine learning
optimization space exploration
stencil
Advisor: Abdelrahman, Tarek S
Family Matters: People’s Perceptions of Family Members Dating Interracially

Family members significantly influence dating behaviors and their support is instrumental for a healthy relationship (e.g., Wang et al., 2006). Although many interracial couples report family disapproval of their relationship (e.g., Inman et al., 2011), few studies have asked family members directly about their attitudes towards these couples. We asked three-hundred twenty-nine White participants how they feel, what they think, and how they would behave towards a couple consisting of either their brother or their sister with a White, Black, or Asian partner. Results revealed that participants’ level of internal motivation to control prejudice (IMS) consistently moderated perceptions of interracial couples. Specifically, high levels of IMS were associated with positive affect, beliefs, and behaviors towards White siblings dating a non-White partner. The findings suggest that IMS may be key in understanding how individuals perceive interracial couples involving a family member.

Keywords: Family
Intergroup Relations
Interracial Dating
Prejudice
Stereotyping
Advisor: Chasteen, Alison L
Effect of Geometry and Bonding Method on the Convective Heat Transfer Enhancement from Copper Foam Partially Filling a Channel

Copper foam with a 10 PPI linear pore density was used to enhance convective heat transfer from a heat sink in which the foam only partially filled the airflow channel. During initial tests with a 100 W heat input, and 6-7 CFM airflow rate, it was found that bonding together two pieces of copper foam with the same geometry provided worse heat transfer compared to a single foam layer. However, improved heat transfer was obtained when smaller pieces of foam that did not completely cover the first layer were added. Next, a heat sink made by solidifying molten tin around copper foam was tested at varying heat inputs and flow rates. The results were compared against tests performed on a heat sink made by soldering copper foam. The new fabrication method using tin was found to provide better heat transfer at a given pressure drop compared to soldering.

Keywords: Convection
Fluid mechanics
Heat transfer
Metal foam
Advisor: Chandra, Sanjeev
Sedentary Behaviour Profiling in Breast Cancer Survivors and Implications for Mental Health

Background: Symptoms of depression remain under diagnosed but highly prevalent in breast cancer survivors (BCS). Reducing sedentary behaviour (SED) during the early survivorship period may be a strategy for treating clinical depression in survivors. Methods: One hundred and eighty-seven BCS provided baseline demographic, medical, and SED/physical activity data. Depression was reported three months later. Multiple dimensions of SED were identified and examined in cluster analysis. The association between cluster membership and depression was assessed using logistic regression. Results: Two SED groups were identified representing higher and lower SED. High SED cluster BCS’s were significantly older, heavier, less physically active, less educated, and were more likely to have undergone lymph/axial node dissection. In the logistic regression model cluster membership was a significant predictor of clinical depression. Conclusions: Reducing dimensions of SED during the early survivorship period could protect from clinical depression symptoms.

Keywords: breast cancer survivors
cancer
depression
mental health
physical activity
sedentary behaviour
Advisor: Sabiston, Catherine
Towards Exploratory Aerodynamic Design using the Reynolds-averaged Navier-Stokes Equations

The aerodynamic optimization framework Jetstream is applied to problems involving lift-constrained drag minimization using the Reynolds-averaged Navier-Stokes equations. A parallel Newton-Krylov algorithm is used to solve the governing equations on multiblock structured meshes; gradients are computed using the discrete-adjoint method. Geometry parameterization and mesh movement are integrated using B-spline control volumes. Drag minimization studies from past works are revisited and strategies are devised to improve optimization convergence. These strategies include linear constraints for geometric feasibility, robust flow solver parameters, and meshing with an O-O topology. The single-point and multi-point optimization of the NASA Common Research Model (CRM) wing geometry is presented. A rectangular NACA0012 wing is optimized with planform design variables, enabling significant changes in span, sweep, taper, and airfoil section. To demonstrate Jetstream’s flexibility, a wing based on the B737-900 is optimized with nonplanar winglets, split-tip, and wingtip fence configurations. Finally, the box-wing optimization in subsonic flow is revisited.

Keywords: Aerodynamics
Computational
Optimization
Advisor: Zingg, David W
Cardiovascular Computed Tomography Phantom Fabrication and Characterization through the Tailored Properties of Polymeric Composites and Cellular Foams

The overall objective of this thesis was to control the fabrication technique and relevant material properties for phantom devices designated for computed tomography (CT) scanning. Fabrication techniques using polymeric composites and foams were detailed together with parametric studies outlining the fundamentals behind the changes in material properties which affect the characteristic CT number. The composites fabricated used polyvinylidene fluoride (PVDF), thermoplastic polyurethane (TPU) and polyethylene (PE) with hydroxylapatite (hA) as additive with different composites made by means of different weight percentages of additive. Polymeric foams were fabricated through a batch foaming technique with the heating time controlled to create different levels of foams. Finally, the effect of fabricated phantoms under varied scanning media was assessed to determine whether self-made phantoms can be scanned accurately under non-water or rigid environments allowing for the future development of complex shaped or fragile material types.

Keywords: Compute Tomography (CT)
Coronary Plaque
CT Phantom
Polymeric Composite
Polymeric Foam
Advisor: Naguib, Hani E
Paul, Narinder S
Theoretical Investigation of Bioactive Papers Using the Kubelka-Munk Theory

This work demonstrates a theoretical study of colorimetric detection of analytes via bioactive papers. A mathematical model incorporating the Kubelka-Munk theory, which analyzes light propagation through paper, was developed. It provides the correlation of color with the concentration of chromophores generated in a reaction between biosensor and analyte as a function of the paper characteristics and optical properties. Accordingly, we evaluate the degree of error of colorimetric readings obtained under various conditions. Theoretical results show that a 5 % variation in reflectance could yield a significant error in detected chromophore concentration. The reflectance is highly affected by environmental illumination and changes in chromophore distribution profile. Confining color detection to the surface of paper is advantageous yet prone to variability due to non-uniformity in analyte or biosensors penetration depth. This work will be, hopefully, incorporated in the initial steps of the bioactive papers design, to obtain more efficient and accurate performance.

Keywords: bioactive papers
colorimetric detection
Kubelka-Munk theory
quantitative
Advisor: Farnood, Ramin
A Comparison of B-spline Surface and Free-form Deformation Geometry Control Methods for Aerodynamic Shape Optimization

The geometry control method employed in an aerodynamic shape optimization algorithm defines what designs can be considered, directly impacting the aerodynamic performance improvements that are attainable by the algorithm. Two geometry control methods, B-spline surface control and free-form deformation, are applied to a suite of problems of varying complexity and are compared on the basis of the quality of the optimized shape as well as the ease of use for problem setup. B-spline surface optimization is often found to result in slightly lower drag; however in general both methods perform equally well, especially when optimized geometries are evaluated on finer grids. The exception is in the case of a dihedral and sectional optimization, where convergence paths taken by the two geometry control methods are significantly different and the B-spline surface optimization reduces drag more effectively. Free-form deformation provides a more general approach to problem setup.

Keywords: Aerodynamics
B-spline surface
Computational fluid dynamics
Free-form deformation
Geometry parameterization and control
Optimization
Advisor: Zingg, David W
Differential Allocation of Male Mating Effort in a Gift-giving Insect

Nuptial gifts, typically beneficial items given by a male to his mate, can be costly and thus can cause males to discriminate between mates. Female black horned tree crickets Oecanthus nigricornis (Orthoptera: Gryllidae) feed on secretions from male dorsal glands, providing an opportunity for males to favor higher quality females by feeding them more. I tested whether such preferential allocation exists in O. nigricornis, when a male encounters multiple receptive females prior to mating and is thus expected to become choosier. Feeding duration, proportion of male-solicited remounts, and singing rates were used as measures of male post-copulatory mate choice. No significant effects were found (perhaps due to low power of the tests) except for an unexpected increase in the singing rate towards high condition females when males encountered multiple males prior to mating. This may be due to males perceiving increased male-male competition on high condition females.

Keywords: male mate condition
mate choice
nuptial gift
Oecanthus nigricornis
operational sex ratio
tree cricket
Advisor: Gwynne, Darryl T
Improving Patient Transportation Performance by Developing and Implementing a Generic Simulation Model

Patient transportation is a department in hospitals responsible for transporting patients or items from one point of a hospital to another. Without proper coordination of this department, patient flow and hospitals functions are impacted. With the end goal of improving portering efficiency, this thesis has two main objectives: the first is to develop a generic portering simulation model; the second is to test the model's generality by using it as a decision support tool to improve porter performance at North York General Hospital and Juravinski Hospital and Cancer Centre. Once the simulation models were validated, improvement scenarios were tested. These scenarios were developed in collaboration with the hospitals involved. The result of this scenario testing yielded an improvement in key performance indicators including: dispatch time, turnaround time and percentage of tasks completed within the target time. This evidence-based research will be used to support future portering improvements.

Advisor: Carter, Michael
Rehabilitation Utilization following a Work-related Traumatic Brain Injury: An Examination of Workers' Compensation Claims in Victoria, Australia

Work-related traumatic brain injury (TBI) is among the most serious types of workplace injuries, yet there is a dearth of research on rehabilitation service use after this occupational injury. The objective of this research was to examine the utilization of four types of rehabilitation services following a work-related TBI in Victoria, Australia; focusing on the differences between men and women and examining other demographic, need, work-related, and geographic factors associated with use. After controlling for demographic, need, work-related, and geographic factors, women were more likely to use physiotherapy compared to men. Men and women were equally likely to use occupational therapy and psychology services. Need-related factors, in comparison to demographic, work-related and geographic factors, were the greatest determinants of the utilization of each type of rehabilitation. Future research is required to determine if the determinants of utilization represent inequalities in healthcare provision following a work-related TBI.

Keywords: Healthcare Utilization
Rehabilitation
Sex and Gender
Traumatic Brain Injury
Work-Related Injury
Advisor: Colantonio, Angela
HIV-1 Envelope Glycoprotein 120 Induced Neuroinflammation Does Not Result in Neurocognitive Impairment in an in vivo Rat Model

Human immunodeficiency virus-1 (HIV-1) infected patients are increasingly experiencing neurocognitive deficits due to low level viral replication and associated inflammation in the central nervous system which results in cellular apoptosis in the brain. The aim of this MSc project was to examine cognitive impairments in learning/memory in the Morris Water Maze using our recently implemented in vivo rat model of HIV-1-induced neuroinflammation by intracerebroventricular administration of HIV-1 gp120ADA. Our findings illustrate that a single dose of 8μg R5-tropic HIV-1 gp120ADA or 50μg lipopolysaccharide elicited a robust proinflammatory cytokine (IL-1β, TNFα) and oxidative stress (iNOS) response in the brain, but only lipopolysaccharide administration activated caspase-3 expression in hippocampal neurons, possibly, resulting in the observed spatial learning/memory deficits. Our gp120ADA-induced neuroinflammatory rat model suggests that acute administration of HIV-1 viral coat protein does not result in neurocognitive impairments, thus alternative gp120 dosing regimens should be considered to establish a model of neurocognitive deficits.

Keywords: HIV-1 gp120
HIV Associated Neurocognitive Disorder
LPS
Morris Water Maze
Neuroinflammation
Advisor: Bendayan, Reina
Indigenous Homelessness and Traditional Knowledge: Stories of Elders and Outreach Support

Aboriginal people are the fastest growing population in Canada. A large portion live off reserves, seeking employment and education in urban centres. While Aboriginal people comprise less than 5% of the population of Toronto, they are overrepresented in the homeless population, at an estimated 15% (Statistics Canada, 2009). There is little known about current life transitions of Aboriginal individuals into cities, and what barriers and supports exist that may put them at risk of homelessness. This study asked: “What are the intersections of traditional Elders, mental health, and homelessness for Aboriginal peoples in Toronto?” The study is based in a conceptual framework of Indigenous knowledges, and employed a narrative methodological structure, using individual interviews to explore stories of Elders and outreach employees from an urban Aboriginal homeless shelter. Results include four metathemes: Traditional Knowledge, Mental Health, Services, and Clients. Limitations, future directions and research implications are discussed in this work.

Keywords: Aboriginal psychology
homelessness
traditional knowledge
Advisor: Stewart, Suzanne L
Schoolyard Farmers: Youth Writing Food Literacy Curriculum

This practitioner research study explores what happens when we invite youth to author curriculum. Ten high school students were hired into paid positions as curriculum writers over the course of three days to work collaboratively to author curriculum for our schoolyard farming program. The chapters of this thesis document the process, explore the implications for my own practice, and share what students wanted their own teachers to know about their experience writing curriculum. Throughout the study I have woven in the ideas of Paulo Freire and a critical conversation about whiteness in this work. Findings suggest that the process of co-authoring curriculum in a way that valued students’ prior food knowledge proved to produce a rich and nuanced curriculum document. Students were also able to transfer their learning to begin to challenge the ways in which power operated in their own classrooms outside of this project.

Keywords: Critical Literacy
Curriculum
Food Justice
Food Literacy
Practitioner Research
Whiteness
Advisor: Simon, Rob
Barriers to Effective RNR Implementation for Youth in the Justice System

Despite robust evidence of the efficacy of the RNR framework, studies indicate that the needs of youth on community supervision as identified in risk-need assessments are frequently not reflected in the services they receive. Potential barriers to treatment were examined in 219 Canadian youth serving probation terms. Ninety percent of youth had a barrier to treatment (M = 4.83 SD = 2.81), with lifestyle destabilizers, engagement issues, parental factors, and probation officers’ case management decisions as the most common categories of barriers. Engagement issues and systems factors were the barrier categories that decreased the likelihood of receiving treatment in the greatest number of criminogenic need domains. Furthermore, barrier categories were related to the likelihood of recidivism. Results call for greater adherence to the Specific Responsivity Principle, expansion to include the assessment and management of destabilizing factors, and attention to larger issues such as the need for a responsive system.

Keywords: assessment
community-based rehabilitation
implementation
risk assessment
risk-need-responsivity
youth
Advisor: Peterson-Badali, Michele
Skilling, Tracey
Response of an Energy-dissipating System to Simulated Blast

Explosions generate extreme overpressures that can cause irreparable damage to critical infrastructure. To mitigate this damage, an energy-dissipating system has been developed that limits peak loads and focuses plastic deformation into replaceable, ductile, steel elements. Cladding panels connect to the structure using these steel energy-dissipating connectors. In a blast, panels transfer pressure load to their perimeter where the sacrificial elements deform at a relatively constant load, thereby restricting the forces transmitted to the underlying structure. This report expands the existing characterization of behaviour for such an energy-dissipating system through experiments with a blast generator. In addition to simulated blast panel tests, tension tests were conducted to determine load-displacement histories under static and dynamic conditions. These histories are then compared to examine the effect of loading rate. Investigations also determined how methods of connector assembly can affect the global behaviour of the system.

Keywords: Blast
Connectors
Dissipate
Energy
Simulated
Advisor: Packer, Jeffrey A
Seica, Michael
Out of the Shadow: Archetypes that Keep Teachers in Patterns of Stress

This study investigates if and how teachers’ relationships to their teaching stress and work transformed as a result of taking part in a workshop designed to have participants interact with the shadow and empowered aspects of five archetypes that manifest in teaching: The Mother, the Servant, the Instructor, the Hero, and the Core Self. The study was conducted in the organic approach through a post-workshop interview. The first part of the study reviews the causes of teacher work stress and burnout, examines the role of beliefs in teacher development and outlines the evidence for and descriptions of each of the archetypes. The second part of the study details the structure of workshop process as well as each participant’s journey through the workshop and personal reflection. The results reveal that by challenging their internal beliefs around archetypal patterns, participants were able to have positive shifts in managing work stress and burnout.

Keywords: Archetypes
Burnout
Teacher Development
Teacher Stress
Advisor: Miller, Jack P
Explorations of the Use of Olanzapine for Management of Chemotherapy-induced Nausea and Vomiting in Children

Control of chemotherapy-induced nausea and vomiting (CINV) in children is sub-optimal and it continues to be a bothersome adverse effect. Effective new antiemetic interventions are required to improve CINV control. The purpose of the projects encompassed in this thesis was to explore the use of olanzapine for management of CINV in children. A systematic review of the safety of olanzapine in children was completed to determine if adverse effects would preclude evaluation of its use for CINV. A retrospective review summarized its efficacy and safety in children with cancer. Based on the results of these projects, olanzapine appears to be safe for use in children with cancer and improved CIV control rates may be achievable when olanzapine is added to antiemetics consistent with clinical practice guidelines. Overall, olanzapine appears to be a promising intervention for management of CINV in children and future prospective, controlled trials evaluating its use are warranted.

Keywords: antiemetic
CINV
olanzapine
pediatric
supportive care
Advisor: Dupuis, Laura L
Walker, Scott