title: A Model Based Fault Detection and Diagnosis Strategy for Automotive Alternators

contributor:
Habibi, Saeid
Mechanical Engineering

subject:
Lundell Alternator
Fault Detection and Diagnosis
Extended Kalman Filter
Smooth Variable Structure Filter
EK-SVSF
Duel Extended Kalman Filter

abstract:
Faulty manufactured alternators lead to commercial and safety concerns when installed in vehicles. Alternators have a major role in the Electrical Power Generation System (EPGS) of vehicles, and a defective alternator will lead to damaging of the battery and other important electric accessories. Therefore, fault detection and diagnosis of alternators can be implemented to quickly and accurately determine the health of an alternator during end of line testing, and not let faulty components leave the manufacturer.
The focus of this research is to develop a Model Based Fault Detection and Diagnosis (FDD) strategy for detecting alternator faults during end of line testing. The proposed solution uses Extended Kalman Smooth Variable Structure Filter (EK-SVSF) to detect common alternator faults. A solution using the Dual Extended Kalman Filter (DEKF) is also discussed. The alternator faults were programmatically simulated on alternator measurements. The experimental results prove that both the EK-SVSF and DEKF strategies were very effective in alternator modeling and detecting open diode faults, shorted diode faults, and stator imbalance faults.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: GENE EXPRESSION IN ESCHERICHIA COLI DURING PROLONGED-INCUBATION

contributor:
Schellhorn, Dr. Herb
Biology

abstract: Environments, where growth is limited by the availability of nutrients are common, for example, soil, water, or even host environments such as macrophages, can lack essential nutrients to support growth. As such, many bacteria spend most of their time in states of little or no growth due to starvation. The starved and growth attenuated state is now widely considered as an important physiological condition in bacterial pathogenesis and survival. Experiments studying stationary phase and adaptation mechanisms to non-optimal conditions lead to the discovery of RpoS as a growth phase-dependent sigma factor. Though RpoS controls many genes in the early stationary phase, it is not known whether RpoS is necessary for prolonged slow growth or not. In a previous study to identify genes controlled by RpoS, we found that a large fraction of the E. coli genome continues to increase in expression during prolonged starvation that does not require RpoS. This suggests that other growth-phase-dependent regulatory mechanism, in addition, to RpoS, may control prolonged stationary phase gene expression. In this study, we examined the abundance of transcripts to identify and characterize the genes that are preferentially expressed during prolonged-incubation phase. RpoS independent genes that are expressed in higher abundance during prolonged-incubation include iron acquisition genes, enterobactin biosynthesis, arginine degradation, and 2-methycitrate pathways enzyme coding-genes. Putative fimbriae genes associated with adhesion to biotic and abiotic surfaces are expressed as RpoS-dependent genes. Furthermore, several biofilm formation genes are expressed in planktonic cultures. Altogether, other regulators, in addition to RpoS, regulate the gene expression during the prolonged-incubation phase and the genes are likely to be important for survival during the prolonged-incubation phase.

abstract: Thesis

abstract: Master of Science (MSc)


title: Making Sense of Social Media for Public Health Decision-makers - The Case of Childhood Immunization in Ontario

contributor:
Abelson, Julia
Health Policy

subject: vaccination, immunization, public health, health policy, social media, social network analysis

abstract: The successful elimination of vaccine-preventable diseases is contingent on high-vaccine coverage rates in targeted populations. The proliferation of vaccine misinformation on social media has led to vaccine hesitancy in the past two decades. A highly contextual phenomenon, areas with an increased prevalence of vaccine hesitancy and vaccine exemption have been shown to correlate with decreased immunization coverage and intermittent vaccine-preventable disease outbreaks worldwide. Although the Canadian government has recommended the use of social media to increase public confidence in vaccines, little documentation exists regarding the perceptions of advisors and decision-makers in policy and communications for immunization towards vaccine hesitancy on social media, and the use of social media to increase public confidence in vaccines in the context of Ontario, Canada’s largest province. This thesis employed 3 unique mixed-methods studies to explore the role of social media in addressing the problem of vaccine hesitancy facilitated through misinformation about childhood vaccines in Ontario. The first study is a social network analysis that incorporates sentiment analysis to demonstrate that pro-vaccine and anti-vaccine communities operate in siloes with little interaction with one another. Those interactions that do occur are most commonly facilitated by sentiment and geographic location, rather than profession or affiliation of the social media user. The second study is a mixed methods content analysis illustrating significant differences in user attributes (emotion, medium shared in tweets, direction of information-sharing, and use of Twitter functions) among pro-, neutral, and anti-vaccine Twitter users, suggesting different motivations underlying Twitter use. Qualitative inquiry of links and reasons for negative vaccine sentiment illustrate the proliferation of pseudo-experts occupying social media, as well as concerns about vaccine safety and mistrust towards the government. The third study complements the first two studies, and uses documents and in-depth interviews with 23 advisers and decisionmakers in policy and communications to illustrate that although vaccine hesitancy is of concern, the use of social media to increase public confidence in vaccines is met with resistance due to a myriad of barriers at all levels of immunization policy and program delivery in the Province of Ontario. Implications for policy and practice of this study include the recognition that a multi-pronged approach is needed to increase the public’s confidence in vaccines. Elements of this multi-pronged approach could include: i) commitments to investing in understanding social media’s use in informing immunization at all levels of governance and decision-making; ii) the active surveillance of public sentiment and the public’s concerns about vaccines on social media using network analysis and content analysis; and iii) the fostering of interdisciplinary collaboration to design interventions that facilitate connectivity between siloes. The implications for future research include the need for continued commitment to the design, implementation, and evaluation of public health interventions on social media in the Ontario context. This study points to the need to pay attention to the behavioral attributes and affordances of social media in order to develop policies, communicative strategies, and programmatic designs that comprehensively address public concerns towards vaccines and, in turn, promote increased confidence in them.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Immunization efforts are integral to maintaining herd immunity. Over the past two decades, it has been observed that vaccine hesitancy brought forth by vaccine misinformation has led to reduced confidence in vaccines, contributing to declining vaccination rates that have subsequently led to outbreaks of vaccine-preventable diseases. Vaccine misinformation on social media has played a crucial role in exacerbating vaccine hesitancy. Limited research has explored the use of social media in the Canadian context in relation to how vaccine information is communicated, what is being discussed and with whom. The extent to which decision-makers working in the immunization policy arena in Canada consider the role of social media as a tool for addressing vaccine hesitancy in order to increase vaccine uptake is also unclear. Using a mixed methods approach, this study, carried out in Ontario, Canada, illustrates that communities supporting and opposing vaccines operate in silos that do not necessarily communicate with each other through social media. Although decision-makers acknowledge the role of social media in the salience of vaccine hesitancy, they consider social media to be a less feasible method to increase vaccine confidence. By exploring the networks and conversations about vaccination on social media, and by understanding decision-makers’ perceptions towards vaccine hesitancy and social media, this study identified gaps between the recommendations for addressing vaccine hesitancy, provincial decision-makers’ preference for addressing immunization, and concerns of the vaccine hesitant on social media. These findings can inform the design of public health messaging to increase the public’s confidence in vaccines in Ontario.


title: Novel Free-Carrier Pump/Probe Techniques for the Characterization of Silicon

contributor:
Kleiman, Rafael
Engineering Physics

subject:
lifetime spectroscopy
recombination lifetime
pump/probe
silicon

abstract: Two novel pump/probe techniques have been developed for measuring the recombination lifetime in crystalline silicon wafers. The first technique, single-beam pump/probe, uses one laser as both pump and probe. The second technique, quasi-steady state free-carrier absorption, measures lifetime under quasi-steady state conditions. These techniques are supported by a general mathematical model that predicts the experimental signal accounting for the 3D charge-carrier transport and recombination within the semiconductor. The predictions of the model are validated experimentally, and quantitative agreement is found between the model and experimental results for both techniques. The recombination lifetime measured by these techniques is verified independently using a standard pump/probe method, and the results are in agreement with this work. Single-beam pump/probe is a first-time demonstration of a technique capable of measuring lifetime in silicon using a single laser beam. It dramatically simplifies traditional pump/probe measurements by completely eliminating the second laser beam. QSS-FCA is the first quasi-steady state technique that can be calibrated in situ without the requirement of a calibrated reference wafer. The calibration constant is the free-carrier absorption cross section of silicon, which is a material constant. QSS-FCA is able to measure this cross section to a higher precision than what has been reported in the literature. Precise measurement of this constant opens up the possibility of studying more fundamental physics of silicon using QSS-FCA.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Clustering Gaussian Processes: A Modified EM Algorithm for Functional Data Analysis with Application to British Columbia Coastal Rainfall Patterns

contributor:
McNicholas, Paul
Mathematics and Statistics

subject:
processes
machine learning
clustering

abstract: Functional data analysis is a statistical framework where data are assumed to follow some functional form. This method of analysis is commonly applied to time series data, where time, measured continuously or in discrete intervals, serves as the lo- cation for a function’s value. In this thesis Gaussian processes, a generalization of the multivariate normal distribution to function space, are used. When multiple processes are observed on a comparable interval, clustering them into sub-populations can provide significant insights. A modified EM algorithm is developed for cluster- ing processes. The model presented clusters processes based on how similar their underlying covariance kernel is. In other words, cluster formation arises from modelling correlation between inputs (as opposed to magnitude between process values). The method is applied to both simulated data and British Columbia coastal rainfall patterns. Results show clustering yearly processes can accurately classify extreme weather patterns.

abstract: Thesis

abstract: Master of Science (MSc)


title: Polymeric Micelles for Ocular Drug Delivery

contributor:
Sheardown, Heather
Chemical Engineering

abstract: Ocular drug delivery to treat diseases of the anterior segment of the eye continues to be a very challenging task. Static barriers include tight junctions of the conjunctiva and dynamic barriers such as the high turnover rate of the tear film contribute to the impenetrable anterior surface. As a result, conventional ophthalmic medication in the form of eye drops is quickly removed and only <5% of the administered dose is efficiently delivered to the anterior tissues. To improve drug delivery into the ocular tissues, we report on a polymeric micelle drug delivery system that may be used to prolong the precorneal residence time of encapsulated drugs. The polymeric micelles were formed from self-assembly of block copolymers composed of poly(L-lactide)-b-polyethylene glycol methacrylate (pLA-b-pEGMA). Atom transfer radical polymerization was used to synthesize these bottlebrush copolymers to increase hydrophilicity, neutrality, surface density and hydrophobic shielding. The micelles were able to achieve an 80% encapsulation efficiency of Cyclosporine A and sustained a release for up to 30 days. By varying the chain lengths of the pLA and pEGMA blocks, micelle sizes ranging from 60-120 nm with a near neutral surface were explored for mucopenetrating properties. These findings illustrate that micelles can reduce the administration frequency, dosage, and side effects associated with conventional eye drops.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Colonial Carcerality and International Relations: Imprisonment, Carceral Space, and Settler Colonial Governance in Canada

contributor: Political Science - International Relations

subject:
settler colonialism
imprisonment
carcerality
Canada
land

abstract:
This dissertation explores the importance of colonial carcerality to International Relations and Canadian politics. I argue that within Canada, practices of imprisonment and the production of carceral space are a foundational method of settler colonial governance because of the ways they are utilized to reorganize and reconstitute the relationships between bodies and land through coercion, non-consensual inclusion and the use of force. In this project I examine the Treaties and early agreements between Indigenous and European nations, pre-Confederation law and policy, legislative and institutional arrangements and practices during early stages of state formation and capitalist expansion, and contemporary claims of “reconciliation,” alongside the ongoing resistance by Indigenous peoples across Turtle Island. I argue that Canada employs carcerality as a strategy of assimilation, dispossession and genocide through practices of criminalization, punishment and containment of bodies and lands. Through this analysis I demonstrate the foundational role of carcerality to historical and contemporary expressions of Canadian governance within empire, by arguing land as indispensable to understanding the utility of imprisonment and carceral space to extending the settler colonial project.

In particular, in this dissertation I focus on demonstrating the relationships between historical and contemporary logics, institutions, and everyday practices of imprisonment and carcerality, and the role they play in the reproduction and maintenance of settler colonial governance within the Canadian context. The central contribution I make in this project is the concept of ‘colonial carcerality,’ which I argue is a governance strategy that relies on inflicting ongoing harm to land, and to Indigenous, gender non-conforming and poor people of colour through criminalization. Drawing on the concept of colonial carcerality provides a framework to understand land as integral to the production of carceral space through the racialized, gendered, sexualized and classed hierarchies that make Canada possible as a settler state within empire. I show how that the criminalization of Indigenous persons through relationships to land occurs alongside the production of settler innocence, and that a carceral apparatus is produced through the preservation white heteropatriarchy alongside the subjugation of land. Drawing from the contributions of Indigenous resurgence and Indigenous feminist literature, this concept provides a theorization of carceral space beyond governance that highlights ongoing harm to land, waters and other living beings as a condition of possibility for carcerality within settler colonialism. It further draws from these insights to begin to imagine possibilities for restorative justice that value the life of all living beings as an entry point into understanding decolonial abolition within the settler colony.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Fabrication of a GaP Nanowire Betavoltaic Device Using Ni-63

contributor:
LaPierre, Ray
Engineering Physics

subject: Betavoltaics, Nanowires, GaP, Sol-Gel, Ni-63

abstract:
The functionality of a novel 3-dimensional betavoltaic battery design will be investigated
to improve conversion efficiency over existing planar devices. A beta-emitting isotope
of nickel, Ni-63, is embedded in the volume of empty space between self-assisted p-i-n
junction gallium phosphide nanowires to improve the beta capture efficiency. Parameters
such as nanowire pitch, diameter, and height will influence the efficiency and were investigated
thoroughly. Material selection was performed based on the following considerations.
Gallium phosphide is chosen to achieve a high open circuit voltage under beta exposure.
Ni-63 has an optimal beta energy spectrum for a nanowire device and a half-life of 101 years
for long term application.
The majority of the work focused on the development of the fabrication process,
particularly the radioactive source deposition. The method used for embedding the source
was a citrate-based sol-gel which was spun onto the sample. This method was modified for
this nanowire application and specific challenges to the process are outlined. Furthermore,
the obstacles of working with radioactive materials will be discussed.
The first nanowire-based betavoltaic device is reported to produce beta-generated
current and achieved a beta conversion efficiency of 0.03%. Investigation of the junction
was performed to provide future improvements to the efficiency. Additionally, simulated IV
curves for a non-active sample exhibited a possible conversion efficiency of 1.92%.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: IDENTIFYING PREDICTORS OF RETURN TO WORK AND UNIQUE ASPECTS OF DISABILITY MANAGEMENT IN FIRST RESPONDERS AFFECTED BY MUSCULOSKELETAL INJURIES AND MENTAL HEALTH

title: ANALYSIS OF THE RETURN TO WORK PROCESS FOR FIRST RESPONDERS

contributor:
MacDermid, Joy
Rehabilitation Science

subject:
Return to work
Disability management
First responders
Firefighters
Musculoskeletal injury
Mental health

abstract:
Background: First responders have unique and important roles. The duties performed can be dangerous, physically demanding and stressful, leading to high risks of injury and illness. Because of their unique job demands, it is important to identify aspects of the disability management process and predictors of return to work that are specific to first responders
Thesis Objectives: To analyze first responder disability management claims associated with injuries and mental health issues to determine predictors of return to work and differences in the disability management claims when comparing first responders to high and low demand occupations.
Methods: The claim data were obtained from a disability management company. In the first study, all first responder claims were included in the Cox proportional regression models and the log-rank tests to identify predictors of return to work. For the second study, the claims of high and low demand occupations were randomly age and sex-matched to the first responder claims. Differences in the duration of time off work, the duration of the claim, the injury and mental health diagnoses, and the duties performed when returning to work existed between first responders and the two occupation groups.
Results: Musculoskeletal injuries predicted an increased likelihood of returning to work in a shorter duration of time. Medical report lag and claim lag decreased the likelihood of returning to work. First responders returned to work sooner, had shorter disability claim durations, differed in the injuries and mental health issues sustained, and were less likely to return to their pre-injury duties compared to the two occupation groups.
Conclusions: Predictors of return to work specific for first responders were identified, yet the results lack generalizability. Although first responders returned to work sooner compared to the other occupations, they were more likely relegated to modified duties.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: First responders perform dangerous and stressful work. They are at risk of injuries and illnesses that require time off work to recover. The goal of this dissertation is to identify features of the return to work process that are specific to first responders. The studies found that first responders with injuries like sprains and strains went back to work sooner than those with mental health issues. The study also found that sooner the injury claim was started and the medical information was received, the sooner first responders could return to work. When compared to other injured workers, first responders returned to work quicker, but were more likely to only be able to do modified work rather than their typical jobs. It is important that first responders fully recovery from injuries before they can get return to responding to emergency calls.


title: Alternating Virtual Knots

contributor:
Boden, Hans
Mathematics and Statistics

subject: Alternating Virtual Knots

abstract:
In this thesis, we study alternating virtual knots. We show the Alexander
polynomial of an almost classical alternating knot is alternating. We give a
characterization theorem for alternating knots in terms of Goeritz matrices.
We prove any reduced alternating diagram has minimal genus, and use this
to prove the frst Tait Conjecture for virtual knots, namely any reduced diagram
of an alternating virtual knot has minimal crossing number.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Matrigel alters the expression of genes related to adipogenesis and the production of extracellular matrix in 3T3-L1 cells

contributor:
Raha, Sandeep
Medical Sciences

subject: White adipose tissue; Obesity; Extracellular Matrix; Matrigel; Adipogenesis; Adipocyte differentiation; 3T3-L1 cells

abstract: Studying molecular mechanisms underlying adipocyte differentiation is imperative to understanding adipocyte function and its role in obesity. However, the majority of research exploring adipogenesis is conducted with cell lines cultured directly on tissue culture plastic. Culturing cells on plastic may result in altered proliferation and differentiation, and subsequent change in pharmacological response. The extracellular matrix (ECM) plays a critical role in adipocyte development and survival. It is suggested that cells in vitro express high levels of ECM proteins to compensate for lack of an ECM. Differentiating preadipocytes on a substrate representative of the mature adipocyte extracellular environment may provide a more physiological response to drugs and environmental chemicals. The purpose of this study was to investigate the impact of Matrigel on 3T3-L1 cell growth, differentiation, lipid accumulation and responsiveness to Rosiglitazone. Matrigel decreased 3T3-L1 cell proliferation, enhanced lipid accumulation, and increased expression of adipogenic and lipogenic markers, including PPARγ, C/EBPα, SREBP1c, FAS, LPL, FABP4 and PLIN1. This was accompanied by a decrease in gene expression of ECM proteins, including fibronectin, collagen 1, collagen 3, collagen 4, laminin and collagen 6 in 3T3-L1 cells on Matrigel. Finally, Matrigel enhanced the response of 3T3-L1 cells to Rosiglitazone, which is a known PPARγ agonist and significantly increases lipid accumulation in 3T3-L1 cells. Our results suggest that enhanced lipid accumulation in 3T3-L1 cells on Matrigel is associated with decreased expression of ECM genes. Future studies require investigation of the cell-to-ECM interaction to confirm these findings. This study proposes that the nature of the ECM for cultured adipocytes alters temporal lipid accumulation patterns and response to various drugs as compared to 3T3-L1 cells grown on tissue culture plastic.

abstract: Thesis

abstract: Master of Science (MSc)


title: THE ROLE OF FIREFIGHTER HEALTH AS PREDICTORS OF WORK LIMITATIONS IN FIRE SERVICE

subject: Firefighters; Musculoskeletal pain; Work limitations; Disability

subject: Non-musculoskeletal comorbidity; women

abstract:
Background: Firefighters (FFs) are exposed to life-threatening conditions while carrying out their tasks. These strenuous conditions predispose them to a high rate of disability, morbidity and mortality. These hazardous conditions put them at risk for work limitations, but the literature is scarce in this matter.
Objective: The overarching objective of this thesis is to determine the role of FFs health as predictors of work limitations in fire service. Specifically, the first objective is to determine whether work limitations differ among FFs based on the location or number of painful sites. The secondary objective is to determine whether non-musculoskeletal comorbid health condition predict work limitations among FFs.
Participants: A convenience sample of FFs between the age of 18-60 years working in the province of Ontario, Canada.
Methods: Participants completed either an online or paper-based survey including a work limitation questionnaire(WLQ-26) and a self-reported comorbidity questionnaire. For the first objective, a one-way ANOVA and post hoc test was used to determine the differences in work limitations among FFs based on the number or location of painful sites. For the secondary objective, a univariate linear regression was used to evaluate whether non-MSK comorbid health condition predict work limitations among FFs.
Results: FFs with three or more painful sites had more physical limitations than FFs without pain, (Mean difference=1.03/10; 95% CI: 0.16-1.62; p=0.02). FFs with pain at the region of the spine experienced more physical limitations compared to FFs with no pain (Mean difference=0.89/10; 95% CI: 0.17-1.62; p=0.007). For the secondary objective, univariate analysis showed that having at least one comorbidity(p=0.04) had a small, but significant association with greater mental work limitations (F2,316=2.94; p=0.05; R2=0.02). Separate univariate analysis showed that women FFs having one comorbidity had a small but significant association with physical (R2=0.07; F2,97=3.92, p=0.02) and mental work limitations (R2=0.04; F2,101=1.89, p=0.15) than women without non-MSK comorbidity.
Conclusion: Having multiple painful sites or pain at the spinal region influenced work limitations among FFs. Also, non-MSK comorbidity impacted mental limitations among FFs; especially among women FFs. Therefore, managing MSK and on-MSK comorbidities is a necessary health care goal to prevent work limitations.

abstract: Thesis

abstract: Master of Science (MSc)


title: AN INVESTIGATION OF MULTIPLE-DIGIT CUE COMBINATION:  PSYCHOPHYSICS AND BAYESIAN MODELING

title: MULTIPLE-DIGIT CUE COMBINATION

contributor:
Goldreich, Daniel
Neuroscience

subject:
psychophysics
Bayesian inference
optimal cue combination
tactile perception
multiple-digits
threshold
sensory integration
ideal observer

abstract: In recent years, computational neuroscientists have suggested that human behaviour, including perception, occurs in a manner consistent with Bayesian inference. According to the Bayesian ideal observer model, the observer combines cues from multiple sensory streams as a weighted average based on each cue’s reliability. Most cue-combination research has focused on integration of cues between sensory modalities or within the visual modality. Cue combination within the tactile modality has been relatively rarely studied, and it is still not known whether cues from individual digits combine optimally. In this thesis, we use the ideal observer model to determine whether cues from three different digits are combined optimally. We predicted that cues from multiple digits would be combined according to the optimal cue combination model. To test our hypothesis, we devised a two-interval forced choice (2IFC) task where participants had to discriminate the distal/proximal location of a 1-mm thick edge across the fingerpad(s) of the index (D2), middle (D3), and ring (D4) fingers. We used a Bayesian adaptive method, the ψ method, to compute participants’ psychometric functions for single-digit (D2, D3, and D4) and multiple-digit (D23, D24, D34, and D234) conditions. We determined the stimulus level ∆x, the distance (mm) between the distal and proximal stimuli locations, at 76% correct probability. This distance corresponds to a sensitivity index d'=1 and is the σ value of the participant’s stimulus measurement distribution. We then used the single-digit σ values to predict optimal cue combination for the multiple-digits combinations. We did not observer optimal cue-combination between the digits in this study. We outline potential implications the results of this experimental have on determining how the nervous system combines cues between digits, focusing on theoretical and experimental updates to the experiment that might result in the observation of optimal cue combination between digits.

abstract: Thesis

abstract: Master of Science (MSc)


title: Funny Business: Exploring Inequality in Stand-Up Comedy Work

title: Funny Business

contributor:
Gillett, James
Sociology

subject: Cultural Industries, Creative Work, Work and Inequality, Intersectionality

abstract:
Much of what we know about workplace inequality, we know from studies on work in industrial and information-based economies. There has been less interrogation into how processes of inequality are formed and sustained in creative work and cultural industries. Given the growing trend away from traditional work rooted in formal organizations and toward cultural industries, how can we understand the relationship between work and inequality in non-standard, creative labour? To answer this question I explore the world of stand-up comedy by drawing on 25 semi-structured interviews with stand-up comedians and over one hundred hours of observational data.
	My analysis reveals that comedy work is organized around the image of an ‘ideal worker,’ an ideal maintained by intersubjective mechanisms of rule: diversity logics, compulsory networking, and creative license. The existence of the ‘ideal worker’ influences how, when, and under what conditions work happens in stand-up comedy for those who fall outside of that ideal. Specifically, workers’ social locations shape how they self-manage, marginalized workers must self-regulate in relation to the work (like everyone else) and the ‘ideal worker.’ Finally, the analysis reveals that workers in stand-up comedy use various strategies to negotiate consent and resistance in their work arrangements in terms of where and under what circumstances they work. Overall, this research highlights how the micro politics of capital are informed by larger power relations that sustain inequality in cultural work settings. Specifically, this work demonstrates the need to address how ‘ideal workers’ are maintained in cultural work, as well as how social location shapes processes of self-management and strategic engagement within unequal work environments.

abstract: Dissertation

abstract: Doctor of Social Science


title: Dreaming Betwixt and Between: Oneiric Narratives in Huijiao and Daoxuan's "Biographies of Eminent Monks"

contributor:
Benn, James
Religious Studies

subject:
Chinese Buddhism
Dreams
Huijiao
Daoxuan
Hagiography

abstract:
This project explores the evolution of medieval Chinese Buddhist perspectives on dreams through a series of in-depth comparisons between the oneiric narratives preserved in Huijiao's (慧皎) "Biographies of Eminent Monks" (Gaoseng zhuan 高僧傳 [GSZ]) and Daoxuan's (道宣) "Continued Biographies of Eminent Monks" (Xu gaoseng zhuan 續高僧傳 [XGSZ]), drawing inspiration from contemporary Sinological and Buddhist Studies scholarship, as well as anthropological and psychological perspectives on dreaming. In addition to using these comparisons to address questions related to the diachronic transformation of Chinese Buddhist thought and practice from the early sixth to mid-seventh centuries, I also posit (and provide evidence for) the hypothesis that dreams (and the stories told about them) represent a potent conceptual metaphor for the “betwixt and between” experience of liminality: a hypothesis that I hope inspires discussion and debate in the broader oneirological community.
I approach these topics through four interrelated case studies. Chapter One uses dream narratives to investigate the various modes of oneiric practice ascribed to Chinese monks (and laypeople) in GSZ and XGSZ, focusing on three specific subtopics (dream telling, dream interpretation, and dream incubation) to evaluate the differences between the episodes preserved in both collections. Chapter Two examines the differing ways that Huijiao and Daoxuan engaged with both Chinese and (Indian) Buddhist oneiric conception tropes when describing the birth and early lives of exemplary monks. Chapter Three posits that Huijiao and Daoxuan made distinctive (and historically-situated) use of oneiric narratives to help situate China within the imagined geographies of contemporary Chinese Buddhists. Finally, Chapter Four explores the distinctive ways that oneiric narratives were used in GSZ and XGSZ to negotiate the interactions between exemplary Buddhists and indigenous Chinese religious practices, practitioners and deities.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Pillar[5]arene Decorated Single-Walled Carbon Nanotubes

contributor:
Adronov, Alex
Chemistry and Chemical Biology

subject: Carbon nanotubes

subject: Pillar[5]arene

abstract: Control of single-walled carbon nanotube dispersion properties is of substantial interest to the scientific community. In this work, we sought to investigate the effect of a macrocycle, the pillar[5]arene, on the dispersion properties of a polymer-nanotube complex. Pillar[5]arenes are a class of electron-rich macrocyclic hosts capable of forming inclusion complexes with electron-poor guests, such as alkyl nitriles. A hydroxyl-functionalized pillar[5]arene derivative was coupled to the alkyl bromide side-chains of a polyfluorene, which was then used to coat the surface of single-walled carbon nanotubes. Differentiation of semiconducting and metallic SWNT species was analyzed by a combination of UV-Vis-NIR, Raman, and fluorescence spectroscopy. Raman spectroscopy confirmed that the concentrated nanotube dispersion produced by the macrocycle-containing polymer was due to well-exfoliated nanotubes, rather than bundle formation. The polymer-nanotube dispersion was investigated using 1H-NMR spectroscopy, and it was found that host-guest chemistry between pillar[5]arene and 1,6-dicyanohexane occurred in the presence of the polymer-nanotube complex. Utilizing the host-guest capability of pillar[5]arene, the polymer-nanotube complex was incorporated into a supramolecular organogel.

abstract: Thesis

abstract: Master of Science (MSc)


title: Analysis of Additively Manufactured 17-4PH Stainless Steel

contributor:
Zurob, Hatem
Materials Science and Engineering

subject:
additive manufacturing
17-4PH
laser sintering
3d printing

abstract:
Selective laser melting of nitrogen gas atomized 17-4PH stainless results in up to 50% lower yield strength and 600% higher elongation compared to traditionally processed, wrought 17-4PH.  This drastic difference in mechanical properties is commonly attributed to the presence of high volume fractions of retained austenite within the as-built microstructure.  The factors leading to the increased level of retained austenite have not been clarified in the literature.  Furthermore, the amount of retained austenite reported within published literature vary widely, even with the use of identical process parameters. Manufacturers of selective laser melting systems state that solution annealing and precipitation hardening will achieve traditional mechanical properties, thereby removing all retained austenite.  Once again, it is not clear, how the recommended solution and precipitation treatments lead to the desired changes in microstructure.
The research within this thesis establishes that there is up to 0.12wt% higher nitrogen content within additively manufactured 17-4PH, compared to traditionally manufactured 17-4PH, as a result of the powder atomization process. The increased nitrogen is able to stabilize the austenitic phase by reducing the Ms temperature below ambient temperatures. Fertiscope bulk phase analysis demonstrates that the processing atmosphere during selective laser melting cannot alter the fraction of retained austenite in the as-built material. The depression of the Ms temperature in the printed parts is confirmed by dilatometry.
Due to the TRIP phenomenon, during sample preparation, it was found that the austenite would transform to 80% martensite at the surface. This transformation will greatly impact the phases detected when x-ray diffraction is used for analysis, leading to a wide variety of reported retained austenite values within literature.
A mechanism based on the precipitation of nitrides during solution-treatment has been proposed to explain how heat-treatment of the printed parts can lead to a martensitic microstructure with comparable mechanical properties to those of wrought alloys.

abstract: Thesis

abstract: Master of Applied Science (MASc)

abstract: 17-4PH stainless steel is a martensitic alloy, that can be precipitation hardened when used in traditional manufacturing processes. Within a selective laser melting process, it will exhibit up to 50% lower yield strength and 600% higher elongation. This behaviour is caused by retained austenite, which is stabilized by the introduction of nitrogen during the powder atomization process. As a result, the alloy exhibits transformation induced plasticity. Existing literature states the alloy’s microstructure can be controlled by altering the selective laser melting process atmosphere or using heat treatment to achieve traditional mechanical properties. However, the production and preparation of samples generates a surface transformation which was misinterpreted as a complete bulk transformation. Therefore, the change in microstructure from altering the process atmosphere is only detectable through surface analytical techniques. It is proposed that the rapid cooling rates of SLM form a non-equilibrium state, keeping nitrogen in solution. Subsequent heat treatment allows the formation of nitrides resulting in the Ms being brought above room temperature.


title: Understanding Spatial and Temporal Tensions of Iranian Immigrant Caregiver-employees for Home Environment Design Improvement

contributor:
Williams, Allison
Geography and Earth Sciences

subject:
immigrants
caregiver-employees
spatial and temporal tensions
home environment
Photovoice

abstract:
The growing number of seniors in Canada and worldwide has highlighted the significant role of people providing unpaid care to their loved ones, who are so-called “family caregivers”. A great number of family caregivers are employees working in the paid labor market, who experience additional difficulties as a result of multiple responsibilities in their daily lives. This group of caregivers has to cope with continuous work-related tensions in addition to their daily caregiving burdens. In multicultural nations such as Canada, a great number of caregiver-employees also belong to the immigrant community. While immigrant caregiver-employees (CEs) are faced with extra challenges compared to other CEs, limited research is available for this underrated and overlooked population. This group of CEs have the challenging task of working from home while providing intensive care for their loved one. Therefore, the home environment is an everyday space highly susceptible because of daily spatial and temporal tensions. The current research aims to explore the experience and tensions of Iranian immigrant caregiver-employees in order to assist them in managing their ever-growing responsibilities in the home environment by providing a set of specific home modification strategies.
Initially, CEs major tensions and management strategies are identified by in-depth qualitative interviews. A novel Photovoice methodology is implemented to illustrate these tensions exclusively through self-captured photos. Five major themes are identified for the tensions, which are categorized as: (i) personal, (ii) caregiving, (iii) spatial, (iv) family and social, and (v) temporal tensions. The management strategies utilized by caregivers to cope with these tensions are also organized into five additional themes: (i) spatial, (ii) personal, (iii) social, (iv) monitoring and control, and (v) assistive and supportive strategies. Although, these management strategies are effective in resolving some of the tensions, specific tensions remain unmanaged for immigrant CEs’. Unmanaged tensions are analyzed under the therapeutic landscape framework to improve CEs’ health and well-being. A comprehensive list of architectural home modification strategies is proposed to relieve CEs’ tensions in the home environment. Finally, an ideal home is pictured for Iranian immigrant CEs, considering their most significant spatial, natural, symbolic and social requirements.
The outcomes of the current research will assist immigrant CEs in managing their daily tensions while performing their working and caregiving responsibilities. The proposed home modification strategies will minimize CEs’ tensions to a large scale, improve their level of mental and physical health, and increase their quality of life. Furthermore, the current research results in increased safety and independence for the care recipients.

abstract: Thesis

abstract: Master of Science (MSc)


title: Examining depressive thinking from a functional perspective: Its links with stressors, sadness, and symptoms

title: Depressive thinking

contributor:
Andrews, Paul
Psychology

subject:
depressive rumination
sadness
analytical thinking
expressive writing

abstract: Depression is a condition characterized by sadness and other symptoms, which are implicated in a persistent style of thinking referred to as depressive rumination. The analytical rumination hypothesis argues that depression is an adaptive response to complicated, personal problems, and that rumination involves an analysis of these problems. This analytical rumination has two stages: first, depressive symptoms promote causal analysis (i.e., considering why the problems happened). Causal analysis then leads to problem-solving analysis (i.e., finding ways to deal with problems), which in turn reduces depression. The empirical studies in this dissertation collectively test whether the nature of depressive thinking is consistent with the analytical rumination hypothesis. In Chapter 2, I investigated the temporal order of sadness and the stages of analytical rumination by asking participants to write about their personal problems. This writing paradigm promoted sadness and causal analysis, but not problem-solving analysis, suggesting that depressive symptoms coincide with causal thinking. In Chapter 3, I explored whether emotions during writing were related to analytical thinking by modifying the paradigm to isolate the impact of other factors (i.e., personal experience with the problem and its valence). These factors could not fully account for emotional changes during writing, suggesting that analytical thinking played a role. Analytical rumination is one of several theories of depressive thinking, so in Chapter 4, I conducted a joint factor analysis of four rumination questionnaires and compared the prevalence of the emerging factors. Factors reflecting causal thoughts and problem-solving were most frequently endorsed, even when they were measured in the presence of sadness induced by the writing paradigm in Chapter 5. Furthermore, associations between these factors and depressive symptoms were consistent with the stages of analytical rumination. Overall, my findings suggest that depressive thinking focuses on understanding and solving problems, and it may have functional implications for depression.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)

abstract: Depression is a mental health condition in part characterized by sadness and changes in thinking. One evolutionary perspective argues that depression is a response to complicated, personal problems, and that symptoms of depression, like sadness, help individuals think through their problems. According to this perspective, depressive thinking is analytical, and it involves causal thinking to identify why the problems happened and problem-solving to find potential solutions. In my dissertation, I examine whether individuals engage in causal thinking and problem-solving when they are sad or depressed. My experiments assess whether writing about personal problems promotes sadness and causal thinking, and they examine the impact of analytical thinking on changes in sadness during writing. Because the evolutionary perspective is one of several theories on depressive thinking, I also use a psychometric method to integrate these theories and to examine how causal thinking and problem-solving are linked with sadness and other depressive symptoms.


title: Cisplatin Cytotoxicity is Unaltered by BCL-2 Expression

contributor:
Singh, Gurmit
Biochemistry

subject:
cisplatin cytotoxicity
bcl-2 expression
cytotoxicty
cisplatin

abstract: A major challenge in cancer therapy is the emergence of acquired resistance to a wide range of chemotherapeutic drugs with unrelated structures and activities. Possible mechanisms to explain drug resistance are induction of efflux pumps, activation of scavenging pathways and/or changes in the oncogene status of a cell. A number of studies have shown that overexpression of Bcl-2 confers resistance by preventing drug induced apoptosis. In this thesis, Madin Darby canine kidney epithelial (MOCK) cells were used to investigate the relationship between cisplatin resistance and Bcl-2 expression. In our studies overexpression of Bcl-2 was sufficient in preventing apoptosis induced by serum deprivation. However, treatment with varying cisplatin doses did not induce an apoptotic response. Electron microscopy and in situ DNA end labelling experiments show changes distinct from those associated with serum deprivationinduced apoptosis. Survival as assessed by DNA fluorometry and clonogenic assays clearly demonstrate that the overexpression of Bcl-2 fails to protect against the cytotoxic effects of cisplatin in MOCK cells. Our results show that cisplatin induces a form of cell death distinct from apoptosis and suggests that multiple pathways to cell death exist which are differentially regulated in a cell type-specific and stimuli-specific fashion.

abstract: Thesis

abstract: Master of Science (MS)


title: BALL SCREW LINEAR ACTUATOR CONTROL AND IMPLEMENTATION BY APPLYING LUGRE FRICTION MODEL

contributor:
Yan, Fengjun
Mechanical Engineering

subject:
BALL SCREW
LUGRE FRICTION MODEL
CONTROL

abstract:
The linear actuator is widely used in the industrial and aerospace arenas. The application of the linear actuator varies. The ball screw type linear actuator or ball screw system is one design. The ball screw is a mechanical system that converts rotation motion into a linear motion. The ball screw linear actuator, compared with other linear actuators, has better efficiency, higher speed, less noise, and higher load capacity. Ball screw linear actuators are used in a number of areas, such as coordinated measuring machines, 3D printers, and aerospace actuators.
In this research, the industrial sponsor provided a ball screw linear actuator, and they required its accuracy to be improved. The linear actuator suffers from an accuracy problem due to various reasons. One of the major problems is nonlinear friction, which makes it difficult to estimate using the simple friction model. In this thesis, a LuGre friction model is introduced and applied to the ball screw system. The sponsor’s ball screw system includes the ball screw sliding table, AC servo drive, AC servo motor, and a linear encoder sensor. The hardware control system for the ball screw system needs to be built. Therefore, this thesis describes how a custom ball screw control system was built.
The control hardware ball screw system includes a microcontroller and a custom-made digital-to-analog converter. The linear encoder position sensor’s reading methods were tested and implemented in the microcontroller. A custom digital-to-analog converter was made and tested.
The control algorithms based on the LuGre friction compensator are discussed and were simulated in the Matlab Simulink environment. Then, the physical implementation of the control algorithms on ball screw system hardware were made. Finally, a new proposed control method based on the LuGre friction model performed best in terms of accuracy consistence and tracking compare to the other mentioned controllers.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Sink Electrical Discharge Machining of Hydrophobic Surfaces

contributor:
Koshy, Philip
Selvaganapathy, P. Ravi
Mechanical Engineering

subject:
Hydrophobic
Electrical Discharge Machining

abstract: Water-repellent behaviour, known as hydrophobicity, has recently attracted a great deal of interest due to its applications, such as anti-icing and self-cleaning. The phenomenon of hydrophobicity found in surfaces like lotus leaves is manifest by a hierarchical structure on low-energy surfaces. Fabrication of hydrophobic surfaces has thus far been largely accomplished on polymers and colloidal materials, which are limited by poor mechanical strength that leads to performance degradation over time. To this end, fabrication of a robust metallic hydrophobic surface is the focus of this research. Sink electrical discharge machining is demonstrated to generate hydrophobic surfaces in 7075 aluminum alloy with water contact angles in excess of 150˚.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Adhesives with Controllable Degradability for Wet Cellulosic Materials

title: Degradable Cellulose Wet Adhesives

contributor:
Pelton, Robert
Chemical Engineering

subject:
Cellulose
Adhesion
Interface and Colloid Science
Material Science
Polymer
Pulp an Paper
Chemical Engineering
Chemistry

abstract:
Cellulose wet adhesives are applied to enhance the wet strength of paper products by binding individual paper fibers together. However, the recycling of the wet strength paper is a challenge as the fibers are hard to re-disperse in water. This project demonstrates new strategies for developing cellulose wet adhesives with controllable degradability, facilitating the recycling of wet strength papers.
In this project, regenerated cellulose membranes were used to simulate paper fibers. In adhesion measurements, two wet cellulose membranes were laminated with a thin layer of adhesive (1–30 mg/m2), and the 90-degree wet-peel was used as a measure of cellulose wet adhesion. It was shown that the wet-peel was a simple and reliable method to evaluate the wet adhesives for paper products.
Cellulose wet adhesives, in the form of microgels or linear polymers, were synthesized by incorporation of hydrazide, amine or azetidinium functional groups that can form covalent bonds to cellulose surfaces. Two strategies to design degradable adhesives were demonstrated in this project. 1) Reductant-responsive microgel adhesives were created by introducing cleavable disulfide linkages, either in the polymer chains tethering adhesive groups or as the microgel crosslinks. More than 70% reduction in wet adhesion was achieved after exposure to a reductant. 2) Degradable polymer cohesive bonds were used to “switch off” the cellulose wet adhesion. This adhesive was created by introducing labile boronate-dextran complexes to the PVAm adhesive layer between cellulose surfaces. The introduction of this new interaction between PVAm chains enhanced the cellulose wet adhesion. In response to subtle pH changes or the presence of monosaccharides, the wet adhesion decreased by 60%.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract:
Wet strength is important for paper products such as paper towels and paper packaging. In paper manufacturing, cellulose wet adhesives are applied to enhance the strength of wet papers by “gluing” together individual cellulose fibers. However, the recycling of wet strength papers is a challenge because the current adhesives prevent the easy disintegration of waste paper back to a suspension of discrete cellulose fibers. As an important part of the bio-based economy, the next generation of paper products are required to be both strong in water and easy to recycle. This thesis explores new designs for wet-strength adhesives that will facilitate recycling.
Both nanoparticles and linear polymers were synthesized in this study as cellulose wet adhesives. Many important properties of wet adhesives were probed, including the size of nanoparticles, the pre-treatment of cellulose surfaces, the dosage of adhesives and the choice of adhesive chemistries. A few types of novel cellulose wet adhesives with controllable degradability were synthesized and evaluated. I demonstrated that the cellulose wet adhesion can be “switched off” in response to subtle pH changes, reducing agents or sugars, showing a promising start for the recycling of wet strength papers.


title: Security Breach Disclosure

contributor:
Yuan, Yufei
Business Administration

subject:
Information Security
Breach Disclosure

abstract:
Security breach disclosure is the public disclosure of information regarding a data security incident.  It allows organizations to communicate salient information to the affected parties and stakeholders regarding the nature and impact of the breach, and remediating solutions undertaken regarding the breach.   Recent cases of large-scale security breaches have revealed that security breach disclosure remains a challenging subject for policymakers, practitioners, and researchers.   There is a lack of understanding and consensus on what breaches need to be disclosed and little evidence on how actual practices are employed.
Using an adapted grounded theory methodology that combines computerized textual extraction and ground theory coding techniques, this study explores relevant issues through four research questions with distinct objectives that would enhance understanding of the issues in public breach disclosure.  First, recent regulations from the US, EU, and Canada are reviewed to identify the core elements in breach disclosure. Second, this study develops methods to extract information content from disclosures. Third, matrices and measuring instruments are developed to evaluate the quality, and last, a framework is proposed to map out the paths and directions for future research.  These advancements lay the crucial groundwork in the field of security breach disclosure and will contribute greatly towards future policies, practice, and research.
The expected societal significance of this research is profound.  The research is relevant to practitioners, regulators, and the information security community as it provides valuable insight on current challenges and future directions.   The ultimate goal is to strengthen our understanding of security breach disclosure and enhance the accumulation and transfer of knowledge obtained through security breach disclosure; thereby providing organizations, regulators, and the information security community with the information necessary to develop policies, tools, and controls for identifying, managing, and reducing the risks of future security incidents.     The proposed core elements, methods of extracting relevant information content, quality evaluation matrices, and framework mark a significant advancement towards this vision.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: Recent cases of security breach at Equifax, Yahoo, and Uber have raised attention from the public and regulators on the issues of public disclosure of security incidents. However, the lack of understanding and research in security breach disclosures has hampered our ability in defining what needs to be disclosed, understanding what are actually disclosed, and determining how well the incidents are disclosed.  These issues are urgent and important thus warrant considerable efforts to carefully examine the current landscape of policy and practice, and to provide methods to evaluate disclosures so that meaningful advancements in research and improvements in practice can be made.  This study recommends a set of core elements in disclosure, develops methods to extract information from disclosure, establishes ways to evaluate quality, and proposes a framework that maps out future research.  These are important advancements in the study of security breach disclosure and will contribute greatly towards future policies, practice, and research.


title: Ancestry of Modern Indian Populations

contributor:
Singh, R. S.
Biology

subject:
ancestry
modern india
population

abstract: An analysis of mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs) was done with the primary goal of clarifying the relationship of the Indian population to world populations. Phylogenetically informative RFLP sites were amplified, restricted and scored for 187 Indian-descended individuals. This sample collectively represented a geographically wide distribution, the three main religions present in the subcontinent, and three main caste groups. Thirteen haplotypes were found in the Indian population, and when combined with world population data obtained from the literature, 41 different haplotypes were found. India was found to be significantly different from all world populations under study. In agreement with previously reported results, the Indian population was found to be more similar to European populations than south-east Asian populations, with all Indian populations sharing the European-associated haplotypes 14 and 15 at high frequencies. However, high frequencies of haplotype 30 implied similarity with the Evenk population of Siberia, suggesting a possible north-central Asian origin for the Dravidian and/or Indo-Aryan migration into India. Significant geographical differentiation within India was found, with north-western India having significantly higher frequencies of haplotypes 14 and 15 than Southern India, and lower frequencies of the Evenk-associated haplotype 30. The northwest was also significantly more diverse than other regions of India, most likely due to its location on the main routes of repeated migration into India. Significant differences between religious groups were found to have a geographical basis, while caste groups were undifferentiated from each other and the main religious groups.

abstract: Thesis

abstract: Master of Science (MS)


title: Polyomavirus Enhancer Binding Proteins PEA1, PEA2, and PEA3: Functional Analysis by In Vitro Transcription

title: In Vitro Analysis of Polyomavirus Enhancer Binding Proteins

contributor:
Hassell, John
Biology

subject: polyomavirus

subject: binding protein

subject: functional analysis

subject: in vitro transcription

subject: PEA1

subject: PEA2

subject: PEA3

abstract: The polyomavirus enhancer consists of functionally redundant DNA sub-elements. One such sub-element, element 2, comprises a region with contiguous binding sites, or motifs, for at least three nuclear factors, designated as PEA1, PEA2, and PEA3. Although little is known of PEA2, PEA1 is presumed to be a murine homolog of human transcription activator protein 1 (AP-1), and PEA3 has recently been shown to be encoded by a member of the Ets family of oncogenes. The contributions of each factor to enhancer function are not understood. A cell-free system was devised to assay the individual abilities of the DNA motifs recognized by PEA1, PEA2, and PEA3 to confer transcriptional activation upon a minimal promoter. The motifs were cloned and tested as monomers, as multiple tandem copies, and in paired combinations. The results of these in vitro studies indicate that the PEA1 motif behaves as a low affinity AP-1 binding site; that PEA1 and PEA3, but not PEA2, activate transcription; and that both the PEA1 and PEA3 motifs act synergistically. Band shift titration experiments demonstrated that neither PEA1 nor PEA3 bound to their DNA motifs co-operatively, indicating that synergistic activation of transcription by these factors is not due to cooperative binding. Finally, additional in vitro transcription experiments suggest that PEA1 and PEA3 may co-operate with each other to stimulate transcription. A current model proposes that the minimal sub-units of enhancer structure are small (8-10 base pair) DNA motifs, called enhansons, that act synergistically. I propose that the motifs for PEA1 and PEA3, but not PEA2, are enhansons of the polyomavirus enhancer.

abstract: Thesis

abstract: Master of Science (MS)


title: Low-Cost Easy-to-Use Free Chlorine Sensor for Monitoring Drinking Water

contributor:
Ghosh, Raja
Chemical Engineering

subject:
sensor
free chlorine
low cost
mechanism

abstract:
In this thesis, low-cost free chlorine sensors for monitoring drinking water have been developed.
The starting material, pencil lead, was modified using a ammonium carbamate solution. The main emphasis for this technology is the low cost, scalable and environmental friendly process. The resultant materials were highly sensitive to free chlorine.
The second discovery was an advanced understanding of the unsteady state mass transfer during the sensing process, using the customly expanded Cottrell equation. This method could qualitatively indicated the absence of free chlorine, for applications where the removal of free chlorine is the goal. This method allowed better interpretation of transient data and simplified setup.
The third discovery was the use of pulsed amperometric detection to detect free chlorine at a much higher sensitivity, while reducing the complexity of the setup, further reducing the cost. This method was based on the previous findings plus understanding of the reaction kinetics.
The resultant sensors detected free chlorine with a detection of 0.0414 ppm, while the regulations require the free chlorine to be above 0.2 ppm. The response time was less than three seconds. The range of detection was up to around 20 ppm. The cost of materials for one sensor was less than ten dollars. The maintenance was minimal due to the lack of consumables. The operation could be as a meter or as a device in a large instrument. The target use of the sensors include small and distant communities, bottling industries, fruit and vegetable washing industries. The free chlorine sensing techniques can be readily expanded to biology, environment, and big data applications, based on the knowledge gained through the study.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract:
Low-cost sensors were developed to monitor free chlorine in drinking water for end users, especially in small and distant communities. Free chlorine keeps lethal microorganism pathogens from re-growing after disinfection. Re-growth is more likely to happen in these communities due to poor infrastructure and less usage-driven flow.
The contributions include:
• A low-cost sensing material for free chlorine based on pencil lead
• Determination of operating range of the sensor
• Study of sensing mechanisms
• Efficiency improvement and cost reduction
• Research articles, conference presentations, patent applications, and industrial collaboration based on above research
The resultant sensor is easy to use, robust in practical conditions and requires low maintenance, suitable for small and distant communities. Future work is the integration with sensing systems and the application of knowledge gained in this thesis for sensing applications in other fields.


title: Genetic Dissection of the Drosophila melanogaster Larval Response to Light Measured in Two New Single Larva Assays

title: Genetic Dissection of the D. melanogaster Larval Response to Light

contributor:
Campos, Ana
Biology

subject:
genetic dissection
genetic
drosophila
drosophila melanogaster
single larva assay
light

abstract: In order to initiate a genetic dissection of the Drosophila melanogaster larval response to light, two new single larva assays were designed: the Checker and ON/OFF assays. Each assay allows quantification of different aspects of the larval visual response by permitting the study of discrete behaviours in a single larva. Results of this study indicate that larvae respond to light by modulating their locomotion. In the Checker assay this can be seen as an increase in residence time spent in dark checks. In the ON/OFF assay this can be measured as a decrease in distance travelled during the light pulse, due at least in part to an increase in head swinging. Concomitantly, the larva exhibits a sharp change in direction from its original path when the lights are turned on. When the lights are turned off, the change in direction in the larval path, although smaller than at lights on, is still greater than in the absence of light transitions. Many of the components previously described to function in adult phototransduction and visual system specification, also have roles in the larval photoresponse as mutations in the genes that encode these components, are able to abolish light perception as measured in both the Checker and ON/OFF assays. However, these mutations disrupt only subsets of the behaviours associated with the larval perception of light, thus suggesting the existence of light detecting mechanism independent of the main visual pathway described for the adult visual system.

abstract: Thesis

abstract: Master of Science (MS)


title: Rat Brown Adipose Tissue Uncoupling Protein: Identification of Potential Targeting Sequence(s)

title: Targeting Sequences of Rat Uncoupling Protein

contributor:
Freeman, K. B.
Biochemistry

subject:
adipose tissue
uncoupling protein
targeting se quence
rat brown

abstract: Uncoupling protein, a mitochondrial inner membrane protein found in mammalian brown adipose tissue, functions as an uncoupler of oxidative phosphorylation by serving as a proton carrier when activated, resulting in heat production, the function of the tissue. Unlike most nuclear-encoded mitochondrial proteins, uncoupling protein is not made with a cleavable presequence. With the availability of an uncoupling protein cDNA clone, the region responsible for targeting uncoupling protein to mitochondria was examined using in vitro transcription and translation and import into isolated mitochondria. In order to localize the targeting sequence of uncoupling protein, fusion proteins containing portions of uncoupling protein and uncoupling protein modified by site-directed mutagenesis were constructed and analysed for their ability to be imported. Previously it has been shown that there was a targeting signal within uncoupling protein amino acids 13 to 105 (Liu et al., 1988). However, amino acids 13 to 51 did not target a passenger protein to mitochondria (Liu et al., 1988). Here the role of amino acids 53 to 105 of uncoupling protein in targeting was examined with two new constructs, uncoupling protein amino acids 53 to 105 joined to rat ornithine carbamoyltransferase amino acids 147 to 354 and to mouse dihydrofolate reductase. These two constructs along with uncoupling protein with amino acids 2 to 51 deleted were imported into mitochondria consistent with uncoupling protein amino acids 53 to 105 having a potential targeting role in uncoupling protein. Further, these three constructs were processed upon import. The major processed forms of all three constructs are approximately 20 amino acids smaller than the initial translation product. Both fusion constructs also have an intermediate-sized processed form approximately 14 amino acids smaller than the initial translation product. Processing suggests that at least the amino terminus of these proteins has reached the mitochondrial matrix. The location of the proteins was examined using Na2CO3 extraction. Uncoupling protein and U13-105-OCT (uncoupling protein amino acids 13 to 105 joined to ornithine carbamoyltransferase amino acids 147 to 354) were found in the membrane fraction while the processed forms of Ud2-51 (uncoupling protein with amino acids 2 to 52 deleted) and U53-105-DHFR (uncoupling protein amino acids 53 to 105 joined to dihydrofolate reductase) were found in the aqueous fraction suggesting that uncoupling protein amino acids 2 to 52/53 are involved in membrane localization. Analysis of Ud2-35 (uncoupling protein with amino acids 2 to 35 deleted) revealed that it was associated with both the membrane and aqueous fractions. Analysis of uncoupling protein amino acids 53 to 105 revealed the potential existence of two positively charged amphipathic a-helices. Based on the sizes of processed forms and on the helical wheel projection for the first possible sequence, arginine54 , lysine56 and lysine67 were changed to glutamines, individually and in various combinations using oligonucleotide site-directed mutagenesis. All mutant proteins were imported into mitochondria even when all three basic amino acids were replaced. The results suggest that this portion of uncoupling protein, amino acids 54 to 67, is not a targeting signal in the protein.

abstract: Thesis

abstract: Master of Science (MS)


title: Psychopaths and Moral Responsibility

contributor:
Gedge, Elisabeth
Philosophy

subject:
Psychopaths
Moral Responsibility
Moral Capacities
Cognitive Empathy

abstract: Psychopaths have traditionally been excluded from the moral realm and have regularly been used as a paradigm case for explaining why emotions, or emotional knowledge, is necessary for the acquisition of moral knowledge. Psychopaths possess an affective deficit that results in an almost total lack of empathy. Emotionists argue that emotions (specifically empathy) are central to moral understanding, and that, since the psychopaths possess this affective deficit, they lack the capacity to acquire moral knowledge which is necessary to be morally responsible. Given recent neurological findings regarding psychopaths, I ague that Emotionists cannot use the psychopath as a case example supporting their argument that emotions are necessary for moral knowledge. I argue that despite psychopaths’ affective disorder, they possess three of the capacities (via cognitive mechanisms) considered by many to be necessary for moral responsibility. Those three capacities are the capacity to acquire moral knowledge, the capacity to be reason-responsive to moral demands, and the capacity to control one’s actions in light of moral demands and reasons. The upshot of my analysis is a rethinking of what it means to possess the right kind of emotional knowledge and a rethinking of the capabilities of psychopaths in relation to the moral realm.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)

abstract: The commonly held view in philosophy is that psychopaths are not morally responsible. Psychopaths amount to about 1% of the current population and up to 25% of male criminal offenders. While these numbers seem rather small in comparison to the total population, philosophers, psychologists and behavioural psychologists regularly point to psychopaths for insight into the moral realm. The main aim of this dissertation is to block the Emotionist argument that emotions are necessary for moral knowledge and argue that psychopaths, despite their affective disorder, possess three of the capacities considered by many to be necessary for moral responsibility. The three capacities are the capacity to acquire moral knowledge, the capacity to be reason-responsive to moral demands, and the capacity to control one’s actions in light of moral demands and reasons. I conclude by arguing that psychopaths are capable of moral responsibility from a cognitive standpoint and that the Emotionist argument must seek another route to establish its conclusion that emotions are necessary for moral knowledge.


title: ONE-DIMENSIONAL HIGH-FIDELITY AND REDUCED-ORDER MODELS FOR THREE-WAY CATALYTIC CONVERTER

subject:
TWC
High-fidelity model
Reduced-order model
Thermal management system
Chemical kinetic

abstract:
To improve the performance of the three-way catalytic (TWC) converter, advanced control strategies and on-board diagnostics (OBD) systems are needed. Both rely on a relatively accurate but computationally efficient TWC converter model. This thesis aims to develop a control-oriented model that can be employed to develop the control strategies and OBD systems of the TWC converter.
The thesis consists of two parts, i.e., the high-fidelity model development and the model reduction. Firstly, a high-fidelity model is built using the energy and mass conservation principles. In this model, a constant inlet simulation is used to validate the warming-up characteristics, and a driving cycle simulation is used to calibrate the reaction rate parameters. The results of the simulation show that the high-fidelity model has adequate accuracy. Secondly, a reduced-order model is developed based on phase and reaction simplifications of the high-fidelity model. The aim of the development of the reduced-order model is to propose a computationally efficient model for further development of control strategies and state estimators for OBD systems. The accuracy of the reduced-order model is then validated by means of simulations.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Expression of Stationary Phase-Specific, os-Dependent Genes of Escherichia Coli

title: Expression of os-Dependent Genes of Escherichia Coli

contributor:
Schellhorn, Herb
Biology

subject:
phase specific
sigma dependent gene
RNA polymerase
Escherichia coli
gene expression

abstract: In the natural environment, bacteria spend the majority of their existence in periods of starvation. While some Gram positive bacteria, such as Bacillus subtilis respond to this stress by forming highly heat-resistant spores, others, such as E. coli, enter a senescent state known as stationary phase. The stationary phase response is characterized by an increased cellular resistance to stresses associated with dormancy such as heat-shock, oxidative stress and osmotic challenge. These confer the cells the ability to survive prolonged periods of nutrient deprivation. The expression of these genes is regulated in part by os, the stationary phase-specific, alternative sigma factor, encoded by the gene rpoS. Several methods have been used to identify these genes including two-dimensional gel electrophoresis (the expression of more than 30 proteins is absent in a rpoS mutant) and the identification of mutants possessing lacZ fusions that respond to a given related stimulus, such as carbon starvation. On the basis of these methods, the os-regulon is predicted to be quite large. However, only fifteen or so genes have been characterized to date. To identify other os-regulated functions, we have introduced a rpoS::Tn10 null allele into a library of 5000 random lacZ fusion mutants and determined the effects of the null allele upon lacZ expression. One-hundred and five mutants were isolated and the os-dependent phenotype confirmed by complementing the rpoS function. Seventy-three strains were complemented, four were not and complementation results were not obtained for twenty-eight strains. Growth-phase-expression assays performed on the strains demonstrated induction of fusions at the onset of stationary phase, and this induction was reduced or abolished in an isogenic rpoS mutant. Furthermore, each mutant exhibited its own characteristic pattern of induction, consistent with the diversity of factors regulated by os. Identification of selected os-dependent functions was accomplished by sequencing the fusion junctions and comparing the sequence obtained with published E. coli sequence databanks. Results show that six fusions map to open reading frames encoding proteins of unknown function and two do not map to any known region in the E. coli chromosome. One fusion maps to a gene encoding a putative lysine decarboxylase. This enzyme is implicated in the maintenance of medium pH and generation of carbon dioxide for cellular growth. The other maps to a recently identified talB gene. talB encodes a transaldolase protein involved in the pentose phosphate cycle, which generates precursors of nucleic acids, aromatic amino acids, and vitamins.

abstract: Thesis

abstract: Master of Science (MS)


title: Improved Methods for Interrupted Time Series Analysis Useful When Outcomes are Aggregated: Accounting for heterogeneity across patients and healthcare settings

contributor:
Hamid, Jemila S
Health Research Methodology

subject:
Interrupted time series
Segmented regression
Weighted segmented regression
Scoping review
Simulation study
Aggregated data
Empirical Evaluation

abstract: This is a sandwich thesis

abstract:
In an interrupted time series (ITS) design, data are collected at multiple time points before and after the implementation of an intervention or program to investigate the effect of the intervention on an outcome of interest. ITS design is often implemented in healthcare settings and is considered the strongest quasi-experimental design in terms of internal and external validity as well as its ability to establish causal relationships. There are several statistical methods that can be used to analyze data from ITS studies. Nevertheless, limitations exist in practical applications, where researchers inappropriately apply the methods, and frequently ignore the assumptions and factors that may influence the optimality of the statistical analysis. Moreover, there is little to no guidance available regarding the application of the various methods, and a standardized framework for analysis of ITS studies does not exist. As such, there is a need to identify and compare existing ITS methods in terms of their strengths and limitations. Their methodological challenges also need to be investigated to inform and direct future research. In light of this, this PhD thesis addresses two main objectives: 1) to conduct a scoping review of the methods that have been employed in the analysis of ITS studies, and 2) to develop improved methods that address a major limitation of the statistical methods frequently used in ITS data analysis.  These objectives are addressed in three projects.
	For the first project, a scoping review of the methods that have been used in analyzing ITS data was conducted, with the focus on ITS applications in health research. The review was based on the Arksey and O’Malley framework and the Joanna Briggs Handbook for scoping reviews. A total of 1389 studies were included in our scoping review. The articles were grouped into methods papers and applications papers based on the focus of the article. For the methods papers, we narratively described the identified methods and discussed their strengths and limitations. The application papers were summarized using frequencies and percentages. We identified some limitations of current methods and provided some recommendations useful in health research.
	In the second project, we developed and presented an improved method for ITS analysis when the data at each time point are aggregated across several participants, which is the most common case in ITS studies in healthcare settings. We considered the segmented linear regression approach, which our scoping review identified as the most frequently used method in ITS studies. When data are aggregated, heterogeneity is introduced due to variability in the patient population within sites (e.g. healthcare facilities) and this is ignored in the segmented linear regression method. Moreover, statistical uncertainty (imprecision) is introduced in the data because of the sample size (number of participants from whom data are aggregated). Ignoring this variability and uncertainty will likely lead to invalid estimates and loss of statistical power, which in turn leads to erroneous conclusions. Our proposed method incorporates patient variability and sample size as weights in a weighted segmented regression model.  We performed extensive simulations and assessed the performance of our method using established performance criteria, such as bias, mean squared error, level and statistical power. We also compared our method with the segmented linear regression approach. The results indicated that the weighted segmented regression was uniformly more precise, less biased and more powerful than the segmented linear regression method.
	In the third project, we extended the weighted method to multisite ITS studies, where data are aggregated at two levels: across several participants within sites as well as across multiple sites. The extended method incorporates the two levels of heterogeneity using weights, where the weights are defined using patient variability, sample size, number of sites as well as site-to-site variability. This extended weighted regression model, which follows the weighted least squares approach is employed to estimate parameters and perform significance testing. We conducted extensive empirical evaluations using various scenarios generated from a multi-site ITS study and compared the performance of our method with that of the segmented linear regression model as well as a pooled analysis method previously developed for multisite studies. We observed that for most scenarios considered, our method produced estimates with narrower 95% confidence intervals and smaller p-values, indicating that our method is more precise and is associated with more statistical power. In some scenarios, where we considered low levels of heterogeneity, our method and the previously proposed method showed comparable results.
	In conclusion, this PhD thesis facilitates future ITS research by laying the groundwork for developing standard guidelines for the design and analysis of ITS studies. The proposed improved method for ITS analysis, which is the weighted segmented regression, contributes to the advancement of ITS research and will enable researchers to optimize their analysis, leading to more precise and powerful results.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Length Polymorphism in the Threonine-Glycine Repeat Region of the Period Gene in Drosophila melanogaster

title: Polymorphism in the THR-GLY Region of the Period Gene

subject:
polymorphism
threonine-glycine
drosophila melanogaster
period gene

abstract: The period gene determines biological rhythmicity in Drosophila melanogaster. The X-linked gene is 7.4kb, containing 8 exons and 7 introns from which a 4.5kb message is translated. A striking feature of the protein encoded by per is a series of alternating threonine-glycine residues in the fifth exon. Moreover, this string of residues is polymorphic for length variation in natural populations, the most frequent variants having 17, 20 or 23 Thr-Gly pairs. In the present study, a geographic analysis of this polymorphism within North American populations was conducted, the results of which indicate significant variation of allele frequency with latitude. The use of spatial autocorrelation analysis and Mantel tests clearly show that the most common variant, encoding 17 Thr-Gly pairs, exhibits a clinal pattern in its distribution along a north-south axis. Furthermore, DNA sequence analysis of several variants has uncovered a novel new variant which encodes 22 Thr-Gly pairs whose nucleotide sequence differs from any published data. Similar statistical analysis conducted on seven allozymes for populations collected along the same transect shows that several have monotonic clinal patterns in their allele frequency distributions which also show correlation with latitude. A previous study of morphological traits on the same populations showed the existence of a non-monotonic clinal pattern. Comparison of the results observed for the molecular and morphological markers indicates that they are subject to different evolutionary forces. The results highlight the importance of comparing patterns of geographic variation using different genetic elements.

abstract: Thesis

abstract: Master of Science (MS)


title: Population Genetics of Hudson Bay Beluga Whales (Delphinapterus leucas): An Analysis of Population Structure and Gene Flow using Mitochondrial DNA Sequences and Multilocus DNA Fingerprinting

contributor:
White, Bradley
Biology

subject:
hudson bay
beluga whale
population structure
gene flow
mitochondrial DNA sequence
multilocus DNA fingerprint
DNA fingerprinting

abstract: Beluga whales in Canadian waters are subdivided into at least six genetically distinct stocks maintained by geographic separation and philopatry to estuaries in summer. Belugas in eastern and western Hudson Bay have previously been shown to be compose genetically distinct populations using mitochondrial restriction analysis. It is not known whether these stocks are further subdivided on the basis of specific estuarine use. Mitochondrial DNA control region sequences were used to investigate variation among belugas sampled at several sites along eastern Hudson Bay, Hudson Strait and Ungava Bay. 320 bp were sequenced, including the highly variable 5' region of control region, in 126 belugas. 17 variable sites and 17 haplotypes, which clustered into 2 related groups, were detected among the whales sequenced. Haplotypes of group A were found mostly in eastern Hudson Bay sites, while B group haplotypes were predominant in northern populations. Significant differences in frequencies of haplotype groups were found between eastern Hudson Bay and Southern Hudson Strait/Ungava Bay populations, indicating they are genetically distinct populations. Haplotype distribution patterns also suggested possible differences between belugas using different estuaries along eastern Hudson Bay. The presence of both groups in each population indicated some exchange of individuals between populations, and/or between eastern and western Hudson Bay. Multilocus DNA fingerprinting was used to investigate the extent of gene flow between eastern and western Hudson Bay belugas via interbreeding on common wintering grounds in Hudson Strait. Belugas from St. Lawrence estuary and the Mackenzie Delta were also analyzed to measure their genetic relatedness to Hudson Bay whales as well as for purposes of comparison to earlier fingerprinting analyses. While results supported lower genetic diversity within the St. Lawrence population, the range of bandsharing within and between populations was otherwise low (0.09 -0.17 for Jeffreys 33.15 and 0.12-0.22 for Jeffreys 33.6). Mantel tests showed differences among St. Lawrence, Hudson Bay, and Mackenzie Delta populations, but not within Hudson Bay. The conflicting nature of the data did not allow conclusions regarding gene flow. Therefore, DNA fingerprinting was not considered to have provided sufficient resolution in addressing this issue.

abstract: Thesis

abstract: Master of Science (MS)


title: Surface Modification of pHEMA with Phenylboronic Acid for Corneal Regeneration

contributor:
Sheardown, Heather
Biomedical Engineering

subject:
Surface modification
Polymer
Cornea
Tissue engineering
Biomaterials
Eye

abstract:
Corneal diseases and insults can result in opacification of the cornea and ultimately lead to blindness. Treatment options for patients are limited due to limited donor availability and the fact that many patients are not eligible for certain treatments due to the nature of their condition. When conventional treatment options are not beneficial for a patient, artificial corneal replacement is necessary. Current artificial replacements induce epithelial downgrowth, where the remaining host corneal cells grow underneath the replacement ultimately leading to implant extrusion. Therefore, surface modification of these synthetic materials is necessary in order to allow proper epithelialization on the surface.
	This work focuses on the creation of a novel corneal scaffold consisting of poly(2-hydroxyethyl methacrylate) (pHEMA) which is surface modified by 3-(acrylamido)phenylboronic acid (APBA), a molecule known to have cell-binding properties through its ability to bind sugars found throughout the cell membrane.  Surfaces were modified using two different polymerization techniques: conventional free radical polymerization (CFRP) and a controlled polymerization technique known as atom transfer radical polymerization (ATRP). It was hypothesized that ATRP would yield more uniform APBA brushes than the conventional method, and therefore create a more efficient cell-binding surface than the conventional method.
	Following each modification, the surface chemical composition of the materials was confirmed by ATR-FTIR, XPS and surface wettability measurements. Once prepared, NIH 3T3 mouse embryo fibroblasts were seeded onto the surfaces and cell viability was assessed through an MTT assay. The results revealed no cell viability on the APBA-modified surfaces, with surface hydrophobicity, grafting density and surface toxicity (for surfaces modified through ATRP) contributing to the lack of cell attachment.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Controlling the flow of light with waveguide encoded slim polymer films

contributor:
Saravanamuttu, Kalaichelvi
Chemistry and Chemical Biology

subject:
light flow
waveguide lattices
planar films

abstract: Manipulating the flow of light is critical in the design and fabrication of light-based devices ranging from solar cells, smart cameras, liquid crystal display (LCD) screens, projectors and light emitting diodes (LEDs). Thin films configured with spatial patterns or modulations in refractive index exhibit strong and richly varied interactions with light beams. In this thesis, we show that embedding planar films with specific geometries of waveguide lattices allows precise control over the inflow and outflow of light. Specifically, we demonstrate the fabrication of a new class of waveguide-encoded polymer films that are generated through a single-step, room temperature technique. Here, waveguide encoded lattices with a range of symmetries are spontaneously inscribed in photopolymerizable resins by self-trapped beams of incandescent light. We describe the generation of lattices consisting of five intersecting arrays of waveguides, which confer a range of unprecedented properties including a large, panoramic field of view (FOV) infinite depth of field and multiple imaging functionalities including focusing and inversion. We have also fabricated lattices inspired by natural arthropodal compound eyes, which comprise a radial distribution of waveguide and in turn impart a continuous, enhanced FOV. We demonstrate the application of these films in controlling the beam profiles of LEDs including their divergence and convergence. Finally, we show that thin films patterned with a periodic array of planar waveguides serve as effective beam steering coatings, which deflect light away from the metallic front contacts of commercially available solar cells and in this way, increase their efficiency.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: STUDY OF LASER SPECKLE REDUCTION FOR LASER DISPLAY APPLICATIONS

contributor:
Xu, Changqing
Engineering Physics

subject: Laser Display Projection Speckle Optics

abstract:
Laser-based projection displays have been under active development over last few years. Lasers are considered as the next generation light sources for projection due to advantages including wide color gamut, high brightness, long lifetime and high electric-optic efficiency. However, speckle phenomenon caused by the coherence of lasers can greatly influence the quality of projected images. A cost effective, easy setup and robust speckle reduction system for laser projection is still very challenging.
	The aim of this thesis is to investigate practical speckle reduction solutions for laser projection system. The system is divided into different modules and for each module, speckle reduction methods are studied. The study includes a low speckle laser source, an optical engine with integrated speckle reduction methods and a low speckle engineered screen. A standard speckle measurement system corresponding to human perception is also presented.
	For low speckle laser source, a theoretical model that describes wavelength diversity in speckle reduction is established. The speckle contrast ratio (SCR) of the system can be simulated. The result is experimentally verified. Guidelines for optimized wavelength/power selection for lasers to generate reduced speckle are proposed. After this, a low cost, high compact and high-efficiency speckle reduction optical system using an electric elastomer actuator is studied. Both theoretical analysis and experimental work are presented and a SCR as low as 3.7% was achieved. Besides these two parts, an engineered screen that utilizes micro lens array (MLA) which can greatly reduce speckle is studied. A comprehensive theoretical model was established for the simulation and optimization of MLA in speckle reduction. The simulated results agree well with reported values. Guidelines in MLA selection for laser projection are presented.
In the last part, a standard measurement setup of speckle in a laser projection system that matches the human perception is studied. Conditions including camera F/#, focal length, integration time and measuring geometry are discussed and suitable setups are proposed.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Novel Image Interpolation Schemes with Applications to Frame Rate Conversion and View Synthesis

contributor:
Shirani, Shahram
Electrical and Computer Engineering

subject:
Image interpolation
View synthesis
Frame rate conversion
Image processing
Depth image based rendering
Free viewpoint TV

abstract:
Image interpolation is the process of generating a new image utilizing a set of available images. The available images may be taken with a camera at different times, or with multiple cameras and from different viewpoints.  Usually, the interpolation problem in the first scenario is called Frame Rate-Up Conversion (FRUC), and the second one view synthesis.
This thesis focuses on image interpolation and addresses both FRUC and view synthesis problems. We propose a novel FRUC method using optical flow motion estimation and a patch-based reconstruction scheme. FRUC interpolates new frames between original frames of a video to increase the number of frames, and increases motion continuity.
In our approach first, forward and backward motion vectors are obtained using an optical flow algorithm, and reconstructed versions of the current and previous frames are generated by our patch-based reconstruction scheme.
Using the original and reconstructed versions of the current and previous frames, two mismatch masks are obtained. Then two versions of the middle frame are generated using a patch-based scheme, with estimated motion vectors and the current and previous frames. Finally, a middle mask, which identifies the mismatch areas of the two middle frames is reconstructed. Using these three masks,  the best candidates for interpolation are selected and fused to obtain the final middle frame.
Due to the patch-based nature of our interpolation scheme most of the holes and cracks will be filled.
Although there is always a probability of having holes, the size and number  of such holes are much smaller than those that would be generated using pixel-based mapping. The rare holes are filled using existing hole-filling algorithms. With fewer and smaller holes, simpler hole-filling algorithms can be applied to the image and the overall complexity of the required post processing decreases.

View synthesis is the process of generating a new (virtual) view using available ones. Depending on the amount of available geometric information, view synthesis techniques can be divided into three categories: Image Based Rendering (IBR), Depth Image Based Rendering (DIBR), and Model Based Rendering (MBR).
We introduce an adaptive version, patch-based scheme for IBR. This patch-based scheme reduces the size  and number of holes during reconstruction. The size of patch is determined in response to edge information for better reconstruction, especially near the boundaries. In the first stage of the algorithm, disparity is obtained using optical flow estimation. Then, a reconstructed version of the left and right views are generated using our adaptive patch-based algorithm. The mismatches between each view and its reconstructed version are obtained in the mismatch detection steps.
This stage results in two masks as outputs, which help with the refinement of disparities and the selection of the best patches for final synthesis. Finally, the remaining holes are filled using our simple hole filling scheme and the refined disparities. The adaptive version still benefits from the overlapping effect of the patches for hole reduction. However, compared with  our fixed-size version, it results in better reconstruction near the edges, object boundaries, and inside the highly textured areas.

We also propose an adaptive patch-based scheme for DIBR.  The proposed method avoids unnecessary warping which is a computationally expensive step in DIBR. We divide nearby views into blocks, and only warp the center of each block. To have a better reconstruction  near the edges and depth discontinuities, the block size is selected adaptively. In the blending step, an approach is introduced to calculate and refine  the blending weights. Many of the existing DIBR schemes warp all pixels of nearby views during interpolation which is unnecessary. We show that using our adaptive patch-based scheme, it is possible to reduce the number of required warping without degrading the overall quality compared with existing schemes.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)