VictorJuiz/thesis huggingface dataset:
Driving Techniques for GaN Power HEMTs

One of the challenges in the application of GaN power HEMTs is designing the gate driver for optimal performance of the transistors. GaN transistors can switch much faster than silicon (Si) devices and require more precise control on timing. Controlling the ringing oscillation during each switching transient is essential for improved efficiency and electromagnetic compatibility (EMC). In this thesis, two driving techniques are examined. A dynamic gate drive technique is examined for driving cascode GaN devices in a flyback converter using a custom gate driver originally designed for silicon power MOSFETs. A reduction in conducted electromagnetic interference (EMI) of 6dB at 80 MHz is observed. Optimal deadtime is investigated for a class D audio output stage utilizing GaN enhancement HEMTs using commercial gate drivers. Experimental results suggest that a proper selection of deadtime can minimize the losses, EMI, and total harmonic distortion (THD) of the amplifier.

Keywords: Deadtime
Gallium Nitride High Electron Mobility Transistor
Gate Drive
Advisor: Ng, Wai Tung
Adaptively Filtering Trans-impedance Amplifier for RF Current Passive Mixers

Current Passive Mixers represent the state of the art for the signal down-conversion in wireless receivers. In such kind of structures, noise, distortion, and losses are strictly correlated to the stage following the mixer. This thesis proposed a trans-impedance amplifier (TIA) to sense the down-converted current with a new topology that adaptively filters the out-of-band interferers as a function of input current magnitude with a class-AB transconductor in the feedback network. The prototype is implemented in IBM 0.13Îźm CMOS technology, and shows low input impedance with a high-pass shaped noise and distortion profile. The filter cut-off frequency is reconfigurable between 2.8MHz and 12MHz. The prototype consumes 1.92mW of power from a 1.2V supply and the active die area is 0.45mm2. It achieves out-of-band SFDR between 86.8dB and 75.1dB, with the FOM varies between 182 dB(J-1) and 176 dB(J-1).

Keywords: Adaptively Filtering TIA
High FOM
High SFDR
Low Power
Small Area
Advisor: Liscidini, Antonio
Discourse Marker So: A Comparison between English Language Learners and English-dominant Speakers

This thesis investigates how English language learners (ELLs) use the discourse marker so, in comparison to (Canadian) English-dominant speakers (EDSs). The data were collected from audio recordings of 20 one-on-one sessions with ten EDSs, five Korean ELLs, and five Japanese ELLs. Overall, the ELLs employed so in a very similar fashion to the EDSs. The results, however, revealed a notable anomaly in the use of one of so's functions in the ELL data. Overall, the ELLs were found to employ Move so more frequently in comparison to the EDSs. Moreover, an examination of a related Korean and Japanese discourse marker demonstrated the role of L1 transfer in the acquisition of an L2. It was also discovered that greater English-learning experience abroad and self-declared awareness of some of so's functions did not necessarily result in the learners using the discourse marker in a similar manner to the EDSs in the study.

Keywords: Discourse Marker
English-Dominant Speakers
English Language Learners
L1 Influence / Transfer
Second Language Acquisition
Advisor: Kerekes, Julie
The Emergence of Rotating Leadership and Collective Responsibility in Grades 1 and 4

Building cultural capacity for innovation is an educational imperative. Knowledge Building pedagogy aims to engage students in sustained creative work with ideas from the earliest years of schooling, with all students taking responsibility for creating and advancing community knowledge. In this investigation, the online discourse of grade 1 and 4 students was examined to explore the possibility of identifying rotating leadership, a distinctive feature of cyberteams that create knowledge in out-of-school contexts. Network analyses were conducted to examine leadership patterns at the group level, followed by content analyses to understand leadership behaviours at the individual level. Overall, student networks were relatively decentralized, with many students leading the group at different points in time by connecting new or unique ideas to the class discussion. This research represents the first attempt to integrate Collaborative Innovation Network theory and Knowledge Building. Findings are discussed within the context of education for the Knowledge Age.

Keywords: collaborative innovation theory
collective responsibility
knowledge building
knowledge creation
rotating leadership
self-organisation
Advisor: Scardamalia, Marlene
Testing an Approach to Teaching Italian Lyric Diction to Opera Singers: An Action Research Study

Using the qualitative framework of action research (AR), this thesis empirically tested my five session, Italian Lyric Diction Course for Opera Singers by examining the validity and efficaciousness of its design, materials, course content, and pedagogical approach of explicit articulatory instruction (EAI). Data collection instruments included: semi-structured participant interviews, audio recording and transcribing of the classes, and an invited panel of eight observer-feedback experts from the fields of foreign language pedagogy, pronunciation instruction, and Italian language instruction. The data analysis uncovered that my teaching approach was based on a Seven Point Circle (7PC) pedagogical framework which emerged from a set of Twelve Principals governing my teaching process: 1. listening/observing, 2. diagnosing, 3. evaluating the degree of L1 transfer into the L2, 4. spontaneously creating a personalized plan-of-action, 5. determining required background knowledge, 6. determining the ease of attainability by the student, 7. assessing the student's comfort zone.

Keywords: Diction
Instruction
Lyric
Opera
Pedagogy
Pronunciation
Advisor: Piccardo, Enrica
An Analytical Model For Predicting The Behaviour of Laterally Restrained Reinforced Concrete Beams

In this thesis, an analytical model for predicting the response of laterally restrained, reinforced concrete beams and slab strips is proposed. This model is formulated using a sectional analysis approach that assumes plane sections remain plane, and accounts for both material nonlinearities and second-order effects. A refined version of the model is developed to account for varying support stiffness, diagonal compression field action, slip relative to the support, and bond deterioration. The refined model is shown to correlate well with test data from two existing experimental investigations on laterally restrained beams. Finally, a series of parametric studies are presented to illustrate the influence of concrete strength, mechanical reinforcement ratio, second-order effects, and slip at a support on the capacity of laterally restrained beams or slab strips. The proposed analytical model presented in this thesis provides the basis for the development of a simplified method that can be incorporated into design standards.

Keywords: Arching Action
Beam
Membrane Action
Reinforced Concrete
Slab
Advisor: Gauvreau, Douglas P
Content-specific Age-related Effects on Recollection and Familiarity

Recollection declines with age are associated with hippocampal atrophy whereas familiarity sparing with age are associated with rhinal cortices which undergo minimal atrophy. Memory for specific stimuli is also supported by distinct areas (perirhinal for objects and faces, parahippocampal; hippocampus for scenes). The present study investigated age-related differences in recollection and familiarity for objects, faces, and scenes. We predicted that recollection on the rhinal based object and face tasks would be equivalent for the groups, whereas recollection on hippocampally based scene memory would be impaired for older adults. Younger and older adults completed recognition memory tasks from which recollection and familiarity were derived. Recollection was equivalent for older and younger adults for faces and objects, but reduced in older adults for scenes. These results suggest that standing assumptions regarding the universal degradation of recollection are inaccurate.

Keywords: Dual-process
Familiarity
Medial temporal lobes
Memory
Recollection
Stimulus-specificity
Advisor: Anderson, Nicole D.
Barense, Morgan D.
A Family's Perception of Childhood Cancer Survivorship: A Case Study in Resilience

Research on families experiencing childhood cancer and life in remission has focused on negative outcomes and variables. Few studies have explored the process of family resilience through this type of adversity. The purpose of this qualitative case study is to describe the experiences of a family who has survived a paediatric cancer. The central question that informed the study is: What are the accounts of members of a family in dealing with childhood cancer and life in survivorship? One family was interviewed over several months and continued to assist in the data analysis and creation of the findings for this study. It was found that cancer subculture and online community support promoted resilience and adaptation for the family as they dealt with the demands and stress of childhood cancer and remission. Recommendations to the Resiliency Model of Family Stress, Adjustment, and Adaptation, healthcare professionals, and further research were discussed.

Keywords: Cancer Subculture
Childhood Cancer
Ecological Resilience
Family Resilience
Healthcare
Paediatrics
Advisor: Volpe, Richard
Mapping Acoustics to Kinematics in Speech

An accurate mapping from speech acoustics to speech articulator movements has many practical applications, as well as theoretical implications of speech planning and perception science. This work can be divided into two parts. In the first part, we show that a simple codebook can be used to map acoustics to speech articulator movements in natural, conversational speech. In the second part, we incorporate cost optimization principles that have been shown to be relevant in motor control tasks into the codebook approach. These cost optimizations are defined as minimization of integral of magnitude velocity, acceleration and jerk of the speech articulators, and are implemented using a dynamic programming technique. Results show that incorporating cost minimization of speech articulator movements can significantly improve mapping acoustics to speech articulator movements. This suggests underlying physiological or neural planning principles used by speech articulators during speech production

Keywords: Acoustics to Kinematics
Articulatory Inversion
Jerk
Signal Processing
Speech
Speech Articulators
Advisor: Wong, Willy
Distinctive Roles for FANCD2 and FANCJ in the Resection of Radiation-induced DNA Double-strand Breaks in Human Cells

Fanconi anemia (FA) patients are hypersensitive to ionizing radiation and other agents that generate DNA double-strand breaks (DSBs). The major error-free DSB repair pathway in human cells is homologous recombination (HR). In G2-phase cells, the decision to use HR to repair a DSB initiates DSB resection. Notably, siRNA-depletion of the FA protein FANCD2 reduces DSB end resection and RAD51-mediated recombination by 40%. In contrast, depletion of another FA protein FANCJ increases DSB resection and directs 77% more breaks into HR repair. However, FANCJ-depletion affects RAD51 protein production and/or stability, preventing the progression of recombination and HR repair. Taken together, data from this study and the literature suggest that FANCD2 is required in DSB resection where it localizes CtIP to the damaged chromatin and initiates HR. In contrast, FANCJ functions in regulating the proper processing and recombination of DSBs through its direct interaction with MRE11-nuclease and its intrinsic helicase activity.

Keywords: DNA repair
Double strand breaks
DSB resection
FANCD2
FANCJ
Fanconi Anemia
Advisor: Meyn, Stephen
Exploring Context-specific Genetic Vulnerabilities in Human Cancer Cell Lines

Synthetic lethality arises when a combination of mutations in multiple genes leads to cell death, whereas a mutation in only one of them retains cell viability. This genetic concept is exploited for identification of targetable vulnerabilities in cancer. We developed a correlation network based on gene essentiality profiles derived from lentiviral-based genome-wide RNA interference screens across a panel of cancer cell lines from several tissues. Novel context-specific vulnerabilities were predicted from the network and further validated. For example, we found that sensitivity to mitochondrial oxidative phosphorylation inhibition varies amongst ovarian cancer cell lines. We also predicted varying sensitivity against alpha-ketoglutarate dehydrogenase inhibition in breast cancer cell lines. In addition, we identified exonuclease 1 as a sensitizing target in ovarian cancer cell lines expressing wild-type p53. Our findings suggest that our correlation network from functional genetic screens is predictive of context-specific vulnerabilities in cancer cells that help discovery of therapeutic strategies.

Keywords: alpha-ketoglutarate dehydrogenase
context-specific vulnerability
exonuclease1
fitness genes
genetic interaction
oxidative phosphorylation
Advisor: Moffat, Jason
Preliminary Mission Design and Power System Testing for Future Small Satellite Missions at the Space Flight Laboratory

This thesis first describes an automated test system developed for a unit of the Space Flight Laboratory's Modular Power System, the Micro-Switched Power Node. This unit is responsible for controlling, monitoring, and delivering power to loads in small satellites. Automating the test in Python successfully reduced per unit test time from approximately thirty minutes down to six minutes and suggests future test improvements for other Modular Power System components. Next, building upon power system knowledge, the CaneoSat preliminary mission design is presented. This is a Canadian Earth Observation Satellite mission prepared for the Canadian Space Agency's Micromission Clusters Pilots Project. The project combines a set of innovative Earth-observing payloads, developed within Canada, into a single satellite. A complete Phase A preliminary design study is presented, which includes discussion of the system requirements, orbit simulation, mass budget, power budget, and data budget for the conceptual satellite mission.

Keywords: automation
nanosatellite
Phase A
power system
satellite
systems engineering
Advisor: Zee, Robert E
First Principles Investigation of Heterogeneous Catalysis on Metal Oxide Surfaces

Metal oxides possess unique electronic and structural properties that render them highly favourable for applications in heterogeneous catalysis. In this study, computational atomistic modelling based on Density Functional Theory was used to investigate the reduction of carbon dioxide over hydroxylated indium oxide nanoparticles, as well at the activation of methane over oxygen-covered bimetallic surfaces. The first study employed metadynamics-biased ab initio molecular dynamics to obtain the free energy surface of the various reaction steps at finite temperature. In the second study, the nudged elastic band method was used to probe the C-H activation mechanisms for different surface configurations. In both cases, activation energies, reaction energies, transition state structures, and charge analysis results are used to explain the underlying mechanistic pathways.

Advisor: Singh, Chandra Veer
Distributed Circuits in SiGe BiCMOS for Next-generation Fiber-optic Communications

In this thesis, various distributed circuits topologies in SiGe BiCMOS are investigated as a means to overcome the strict requirements of next-generation optical communications. A low-noise DC-135GHz bandwidth distributed amplifier was designed and fabricated in 55nm SiGe BiCMOS for ultra-wideband receiver applications. In the same technology, a novel large-swing, time-interleaved power DAC test circuit was implemented as a proof-of-concept to investigate the maximum achievable bandwidth with a differential output swing of 6 Vpp, as needed to directly drive an optical modulator. Additionally, key blocks of a large-swing frequency-interleaved transmitter architecture were designed and fabricated in a 90nm SiGe BiCMOS technology. These included a 125GHz bandwidth PIN-diode SPST switch with record linearity, a novel vertically-coupled 40-100 GHz band-pass filter, and a large-swing driver with 80GHz bandwidth.

Keywords: Broadband analog
Distributed circuits
fiber-optic communication
IC design
millimeter-wave circuits
SiGe BiCMOS
Advisor: Voinigescu, Sorin P
Formation and Behaviour of Environmentally Persistent Free Radicals from the Heterogeneous Reaction of Ozone with Combustion Particulate Matter

Environmentally persistent free radicals (EPFRs) are paramagnetic species stabilized by interaction with particulate matter (PM), which allows them to persist in the environment for days-weeks. Such species are important because when inhaled they can catalytically generate reactive oxygen species (ROS) which cause oxidative stress and cell death. EPFRs are typically generated during combustion processes, but there is evidence in the literature that semiquinone EPFRs are formed when PM is aged in ambient air. It is known that polycyclic aromatic hydrocarbons (PAH), a common combustion PM (CPM) constituent, react heterogeneously with ozone, and quinone species are major products. In this thesis, using a single experimental method, we find for the first time that the reaction of ozone with PAH and with CPM produce several species of EPFRs. Their formation and behaviour is dependent upon a number of environmental factors including humidity, light, other gas phase radicals, and organic coating materials.

Keywords: combustion particulate matter
environmentally persistent free radicals
heterogeneous reactivity
ozone
particulate matter
polycyclic aromatic compounds
Advisor: Abbatt, Jonathan PD
Drying Characteristics of Biosludge from Pulp and Paper Mills

Biosludge disposal has been a problem for pulp and paper mills due to its high moisture content and poor dewatering/drying characteristics. Most biosludge is landfilled, although some has been used as soil amendment. Some mills mix biosludge with primary sludge, dewater the mixture to 15-30% solids and burn it with hog fuel in biomass boilers. For biosludge to burn effectively, its solids content must be increased to at least 30-35%. However, during drying biosludge becomes sticky, agglomerating and adhering to the dryer wall, decreasing dryer efficiency. This study examines the drying characteristics and sticky behaviour of pulp and paper mill biosludge. The cohesive strength of biosludge was found to be stronger than the adhesive strength, reaching a maximum at 20% solids and 13% solids respectively. The moisture and organic appear to influence sticky behaviour. The addition of wood fines and fly ash did not affect the drying rate, but reduced stickiness.

Keywords: Biosludge
Drying
Pulp and Paper
Sludge
Stickiness
Advisor: Tran, Honghi
Adaptive Perfectionism, Maladaptive Perfectionism, Perceived Stress and Risk of Concussion in Varsity Athletes

Introduction: Psychological variables such as personality, perceived stress and mood have been proposed as antecedents to musculoskeletal injury. Furthermore, a positive relationship between life stress and athletic injury has been reported in the literature. However, these variables have not yet been examined with respect to sport concussion. Purpose and Method: Baseline measures of perfectionism and perceived stress (PS) were examined as potential risk factors for concussion. Specifically, adaptive perfectionism (AP), maladaptive perfectionism (MP), and PS were investigated as predictors of concussion. Mood states were hypothesized to mediate these relationships. A total of 828 varsity athletes completed the Frost Multidimensional Perfectionism Scale, Perceived Stress Scale, and Profile of Mood States (POMS). Results: Significant correlations were found between AP, MP, PS, and the POMS. Based on logistic regression analysis, AP, MP, and PS did not predict concussion occurrence. Conclusion: Risk of concussion is not associated with perfectionism or perceived stress.

Keywords: Athletic injury
Perfectionism
Risk factors
Sport Concussion
Stress
Advisor: Mainwaring, Lynda M
Measurements of Aqueous Droplet Evaporation Rate as a Function of Solute Species

The water content of atmospheric particles determines their size and solute concentration, and thus their phase, gas uptake, reactivity, optical properties, and cloud-forming properties. I have measured the evaporation rate of water from binary and ternary solution droplets using an ultrasonic levitator, and developed a simple model to predict the change in droplet size as a function of solute concentration. The simple model agrees well with experimental results for solutions of simple, non-ammonium salts, and may be used for organic acids with parameterized water activity data. For ammonium chloride and ammonium sulfate droplets, the experimental evaporation rate of subsaturated solutions exceeds the simple model's prediction. For ternary malonic acid/ammonium sulfate/water droplets, the effect of solutes on the evaporation rate of water from subsaturated solutions appears to be additive, and at higher concentrations a drastic reduction to evaporation rate is observed, suggesting that a highly viscous phase is formed.

Keywords: aerosol science
droplet evaporation
ultrasonic levitator
Advisor: Donaldson, D. James
The Creation of Functional Pseudoislets Using Modular Tissue Engineering

Pancreatic islet transplantation exists as an option for treating type I diabetes but is not widely used as there is a shortage of donors and it requires intensive immunosuppression. We investigated aggregating islet cells in modules (injectable microtissue structures) to create pseudoislets that have better vasculature and ability to reverse hyperglycemia. Blood outgrowth endothelial cells (BOEC) are autologous and easily obtained, making them an ideal endothelial cell source. Results showed there were no significant differences in vascularization when using BOEC rather than human umbilical vein endothelial cells (HUVEC) or when embedding them in modules compared to coating them. Diabetic SCID-Bg mice returned to normoglycemia faster when subcutaneously implanted with BOEC coated modules or modules containing ÎąTC1-6 cells along with MIN6 cells (in a 33/67 mix). Future work with stem cell sources could eliminate the strain on donor supply and lead to a long-term solution for those with type I diabetes.

Keywords: BOEC
Diabetes
Islet
Modules
Transplantation
Advisor: Sefton, Michael V.
Exploring Low-coordinate Aluminum-based Lewis Acids for Small Molecule Activation

While there have been a significant number of publications in the field of frustrated Lewis pair chemistry, only a fraction employ aluminum-based Lewis acids. The research presented herein expands the scope of Lewis acids to include novel aluminum-based compounds. N-heterocyclic carbene-stabilized three-coordinate aluminum cations were synthesized from the NHC-AlR3 adduct by abstraction of an R substituent from aluminum. These compounds were crystallographically characterized and exhibited solvent-dependent reactivity. Hydrogenation catalysis and radical reactivity were also explored experimentally and computationally.

Keywords: Aluminum
Carbene
Catalysis
Hydrogenation
Radical
Advisor: Stephan, Douglas W