VictorJuiz/thesis huggingface dataset:
Exploring Theories, Opportunities, and Barriers to Anytime, Anywhere Knowledge Building

The goal of this thesis is to explore the theories, barriers, and possibilities of “anytime, anywhere” Knowledge Building. Knowledge Building assumes students to be legitimate contributors of knowledge and represents an effort to immerse students in the work of advancing conceptual knowledge. Pervasive Knowledge Building is a key principle, which advocates for students’ creative work with ideas that pervades their mental lives within and beyond school. However, Knowledge Building—and use of its supporting technology, Knowledge Forum—are often restricted to set times of the day. This research draws on theories of mobile and seamless learning to inform pervasive opportunities for students to engage with socially created knowledge. The findings are informed by early-stage exploratory research in a grade 6 class which aimed to take work with Knowledge Forum beyond set times of the day and bridge the divide between online and face-to-face discourse.

Keywords: artifacts
Knowledge Building
knowledge creation
mobile-assisted seamless learning
mobile learning
pervasive Knowledge Building
Advisor: Scardamalia, Marlene
Miocene-Pliocene Deformation and Deposition in the Fiambalá Basin, NW Argentina: Implications for Local and Regional Kinematic Evolution

To address questions concerning the evolution of the Precordillera, Puna Plateau and Sierras Pampeanas morphotectonic domains, we explore the tectonic history of the Fiambalá basin, located at the junction of these three domains. We present new field observations and U/Pb geochronology of the Miocene stratigraphy in the Fiambalá basin. Our results suggest a NE-SW oriented regional foreland basin during the deposition of the oldest unit at ~ 8 Ma. We observe a change in orientation of the shortening axis between ~ 8 Ma and ~ 4 Ma from NW-SE to NE-SW, indicated by the onset of Pliocene intrabasin deformation. Depositional ages from the youngest Miocene unit indicate the propagation of deformation from SW to NE through the basin. These observations suggest that the Puna Plateau and Precordillera may have been part of a NE-SW oriented foreland basin, that transitioned to a broken foreland with the uplift of the Sierra Pampeanas.

Keywords: Deformation
Geology
Mapping
Sedimentology
Tectonics
Advisor: Schoenbohm, Lindsay
A Robot Emotion Model for Human-Robot Interaction

In order for socially assistive robots to be successfully integrated within society, they need to be able to respond appropriately to the user during assistive human-robot interactions (HRI). Such robots are expected to interact with humans using natural interfaces. In this thesis, a novel robot emotion model that can be used for social robots engaged in HRI is presented. The proposed model effectively determines the robot’s emotional state based on its own emotion history, the affect of the user whom the robot is interacting with, and the HRI task at hand. The model uniquely uses an nth order Markov Model (MM) to track the robot’s emotion history during interactions. Simulated experiments were conducted using the robot emotion model to persuade different users to comply with various tasks. A human-robot experiment with a social robot as an exercise coach was also designed to test the proposed model.

Keywords: nth order Markov Model
Robot emotion
Advisor: Nejat, Goldie
Benhabib, Beno
New Techniques for High-order Field Sensitivity Analysis with the Finite-difference Time-domain Method

This thesis proposes two techniques to compute the derivatives of electromagnetic fields with respect to multiple design parameters, up to any order, with the finite-difference time-domain (FDTD) method. The first approach is based on coupling the complex-step derivative (CSD) approximation with the standard FDTD update equations. The second method utilizes standard FDTD simulations, mapping geometrical and material perturbations to equivalent sources for the field derivatives. The proposed techniques offer the versatility of standard methods, e.g., finite-differences, while their accuracy significantly surpasses that of finite-differences. The availability of accurate approximations of field derivatives with respect to design parameters enables studies such as sensitivity analysis of multiple objective functions (as derivatives of those can be derived from field derivatives via the chain rule), uncertainty quantification, as well as multi-parametric modeling and optimization of electromagnetic structures. The theory, FDTD implementation, computational complexity and applications of these techniques are presented.

Keywords: Electromagnetic Simulation
Finite-Difference Time-Domain
Sensitivity Analysis
Advisor: Sarris, Costas
Self-collision Detection and Avoidance for Dual-arm Concentric Tube Robots

Recent studies on concentric tube robots (CTRs) have shown that they are well-suited for minimally invasive surgeries. However, typical surgical procedures require the use of multiple tools simultaneously which has led to the development of dual-arm CTRs that are susceptible to self-collision. In this research, a real-time closed-loop control system for dual-arm CTRs is proposed which detects and avoids inter-collision between arms along their entire body. The proposed controller is developed with three prioritized tasks; physical constraints, self-collision avoidance, and end-effector tracking. To avoid self-collision, the minimum distance between the manipulators in the Cartesian space is kept at a pre-set threshold. The experimental results demonstrated the efficacy of the controller in handling self-collision to reach 97.69% of all possible pairs of points in the overlapping workspace of two arms. Further, the maximum RMS tip position error in collision cases, 0.278 mm, was less than 1% of the total robot’s length.

Keywords: collision avoidance
concentric tube robots
Medical robotics
Advisor: Drake, James
Diller, Eric
Temporal Association Coding in the Medial Prefrontal Cortex: Difference in the Role among Distinct Neuron Types

The ability to associate two stimuli that are separated by a temporal gap requires at least two types of information: what has been presented (trace holding) and what will follow (temporal expectation). It has been shown that neurons in the medial prefrontal cortex (mPFC) can be selective for trace holding, temporal expectation or both. It remains unknown, however, what the distinct role of different neuron types is in representing trace holding and temporal expectation. Thus, the present study investigates the role of three distinct neuron types found in mPFC by applying a series of analyses. The narrow-waveform and fast-spiking neurons were more selective for trace holding than temporal expectation. The wide-waveform regular-firing neurons were equally selective for both types of information and the wide-waveform bursting neurons were less selective than the other neuron types. Therefore, I found that three neuron types have distinct contributions to the encoding of temporal association.

Keywords: Associative memory
Computational Neurocience
Machine learning
Memory representation
Prefrontal cortex
Single-unit activity
Advisor: Takehara-Nishiuchi, Kaori
Exact Methods to Solve the Fair Allocation Problem in the Social Needs Marketplace

The Social Needs Marketplace (SNM) is a virtual marketplace that intends to provide a fair and an efficient way to redistribute goods and services to the under-privileged members of the society. This thesis formally defines the allocation problem in the SNM (SNMAP), in addition to showing that the problem’s complexity is NP-complete subject to each of the four fairness criteria (envy-freeness, proportional fairshare, min-max fairshare and max-min fairshare). We provide a formal analysis of these four fairness criteria and show that a dominance ordering does not exist among them in the context of the SNMAP. We also define a variant of the SNMAP, represented by SNMAP-M which optimizes fairness criteria for a given instance. We present Mixed integer programming (MIP) and Constraint programming (CP) approaches to solve both the problems (SNMAP and SNMAP-M). Our empirical analysis on randomly generated problem instances show that MIP models perform better than CP models.

Advisor: Beck, Christopher
The Comparative Evolution of the Floral Traits of Island Angiosperms

Island biotas show parallel changes in community assembly and the evolution of species traits, which are referred to as “island syndromes.” My thesis investigates the evolution of floral traits on islands to test the “island floral syndrome,” which posits that island angiosperms evolve smaller, less showy flowers compared to mainland relatives. To test this hypothesis, I utilize a phylogenetic comparative approach, in which I compare the flower size of 136 island-mainland pairs of sister taxa across seven islands. I found that on average island angiosperms did not evolve smaller flowers relative to their mainland sister taxa. However, I did find that there was significant variation in the evolution of flower size among islands and among taxonomic families, such that, specific island floras and taxonomic families showed evolutionary trends consistent with and in opposition to the island floral syndrome. My thesis contributes to our understanding of the evolution of island floras.

Keywords: angiosperms
island biogeography
island floral syndrome
island floras
islands
island syndromes
Advisor: Johnson, Marc TJ
Validation of Dimethyl-Ether (DME) Combustion Models for use in Internal Combustion Engines

From an environmental point of view, CI engines running on diesel fuel are considered harmful and experimental research has shown that Dimethyl Ether (DME) has the potential to become the fuel of the future due to its clean properties. Ignition delay and laminar flame speed (SL) measurements are some of the important parameters for effective engine design and chemical kinetics modelling. In this study, several chemical models of DME were considered. First, they were validated for ignition delay analysis. The model that was most valid throughout was used for comparison to new experimental measurements of laminar flame speeds of DME and methane-air mixtures in a controlled laboratory environment. Overall, the chemical models of DME, especially the Aramco 2.0 mechanism, showed good agreement with the experimental data sets of ignition delay and SL studies.

Keywords: biofuel
combustion
Dimethyl-Ether
DME
flame speed
ignition delay
Advisor: Thomson, Murray J
Proazaphosphatrane and Bench-stable Carbon-based Lewis Acids in Frustrated Lewis Pair Chemistry

B(C6F5)3 and P(MeNCH2CH2)3N form a classical Lewis adduct, (C6F5)3BP(MeNCH2CH2)3N. Although the adduct does not exhibit spectroscopic evidence of dissociation into its constituent Lewis acid and base, products of frustrated Lewis pair (FLP) addition reactions are observed with PhNCO, PhCH2N3, PhNSO, and CO2. Recently, a bench-stable trityl cation and P(MeNCH2CH2)3N were also found to form a classical Lewis adduct that does not exhibit spectroscopic evidence of dissociation. This adduct was able to carry out the heterolytic splitting of H2. Interestingly, when this and other newly synthesized bench-stable trityl cations were combined with phosphine bases such as P(t-Bu)3 and P(o-tol)3, FLPs capable of heterolytic splitting of H2 were generated and, in at least one case, reversible activation of H2 was observed. These recent findings open avenues towards the application of bench-stable carbon-based Lewis acids for FLP mediated hydrogenation.

Advisor: Stephan, Douglas W.
Characterization of White Adipose Tissue Depots After Burn

Burn injury results in a vast and prolonged hypermetabolic state that is characterized by hyperglycemia, cachexia, organ dysfunction, and death. Recently, the adipose has been identified as a major mediator in the activation of the hypermetabolic response. However, the fat, and in particular, the visceral fat, has been largely ignored within this context. Here, we aimed to characterize and compare some of the hallmark responses of burn injury by examining the largest visceral (eWAT) and subcutaneous (iWAT) depots in our murine model. After a 30% burn, we observed the activation of ER stress, lipolysis and browning in different depots. Administration of propranolol (10 mg/kg) for 5 days attenuated these responses. We conclude that burn studies that examine the fat should be mindful of the depot they survey and be careful not to generalize results. Our findings also highlight the use of propranolol as an adjunct treatment for burn injury.

Keywords: adipose tissue
browning
Burn
ER Stress
fat
lipolysis
Advisor: Jeschke, Marc
Predicting Active Enhancers From Chromatin Accessibility and RNA-seq Datasets

Genomic annotation tools transform vast amounts of genomic data into interpretable labels, and help identify regulatory elements. As genomic assays improve to probe smaller samples of fewer cells, they become capable of characterizing new cell types. Genomic annotation methods must adapt to make sense of this wealth of new information despite the relative dearth of data on protein-DNA interactions on these new cell types, especially for use in locating regulatory elements. This project investigates the effectiveness of Segway, a genomic annotation tool, on minimal amounts of information. This project aims to improve upon existing methods by investigating two new supervised approaches to predict specific regulatory regions (enhancers), elucidating their location given only chromatin accessibility and RNA-seq data. The results show that out of the algorithms available from scikit-learn, an extremely randomized trees classifier is most capable of locating enhancers using minimal data (auPR 0.65).

Keywords: bioinformatics
chromatin accessibility
ExtraTrees
machine learning
RNA-seq
Advisor: Hoffman, Michael M
Autonomic Management System on SAVI-IoT

In the modern era of the Internet of Things and ubiquitous computing, autonomic management has become an essential component in the platforms because of its ability to govern resources adaptively from the sensor layer to the data center. In this thesis, we present an Autonomic Management System (AMS) that is designed to govern compute resources and network bandwidth for IoT applications. Security attacks such as economic Denial of Sustainability (EDoS) make the autonomic system vulnerable to wasting resources and also incur a cost for the application owners. We propose two frameworks using statistical techniques and Hierarchical Temporal Memory to thwart EDoS attacks for the AMS. The AMS has been implemented on the SAVI-IoT platform. The evaluation results demonstrate the system's ability to seamlessly adjust resources based on traffic workload. Further analysis proves its capability to reduce economic damage for the application owner and reduce resource wastage for the infrastructure.

Advisor: Leon-Garcia, Alberto
Onboard Image Processing Algorithms for the BRITE Mission and Development of a Navigation System for Upcoming Formation Flying Missions

This thesis presents contributions to the BRight Target Explorer (BRITE) mission and operational formation flying missions developed at the Space Flight Laboratory. Onboard image processing algorithms were developed to increase science data throughput for the BRITE mission. The algorithms were adapted from a sophisticated ground-based data reduction pipeline developed in parallel with a new operating mode that mitigates the effects of radiation damage to the instrument detector. Onboard processing enables photometric data to be downlinked to the ground rather than entire images, increasing the number of stars that can be observed. The development of the navigation component for a ground-based GNC system for formation flying missions is also presented, focusing on an investigation into the feasibility of commercial orbit determination software for missions with moderate intersatellite baselines and control accuracy requirements. The orbit determination scheme implemented is presented and validated using on-orbit data from the CanX-4/-5 formation flying technology demonstration.

Keywords: BRITE
formation flying
image processing
nanosatellites
navigation
Advisor: Zee, Robert E
A Psychoeducational Intervention for People Affected by Pancreatic Cancer

The two aims of this thesis were to: (1) develop an interdisciplinary psychoeducational intervention for people affected by pancreatic cancer; and 2) evaluate the feasibility, acceptability, and preliminary efficacy of its implementation. All stages of research were informed by implementation science principles. In Study One, we developed Living Well with Pancreatic Cancer—an empirically-based, single session, manualized group intervention focused on supportive care needs in pancreatic cancer. Study Two was a mixed methods study to examine early phase implementation of our intervention in a pancreatic oncology clinic. Content and delivery were acceptable to patients, caregivers, and health care professionals (HCPs). Benefits included improved relationships with HCPs and knowledge of palliative and supportive care. Implementation was feasible, facilitated by stakeholder commitment and research support; however, additional human resourcing is required for sustainability. This research presents an innovative approach to operationalize supportive care and promote uptake of complex interventions into practice.

Keywords: advanced cancer
implementation science
palliative care
pancreatic cancer
psychoeducation
supportive care
Advisor: Rodin, Gary M
Fabrication and Evaluation of PVA Modified Hydrophilic Cellulose Membrane and TiO2/FAS Modified Superhydrophobic PVDF Electrospun Nanofiber Membrane for Applications in Membrane Bioreactor and Membrane Distillation

In this study, two novel membranes were fabricated for membrane-based water and wastewater treatment processes. A PVA modified hydrophilic cellulose membrane was developed for membrane bioreactor, and the fabrication process is based on hand sheet making and dip-coating process. The membrane performance was evaluated based on flux-step experiments and long-term filtration tests. The results suggested that the modified membranes can operate up to 185 hours, and can provide a MLSS rejection that up to 99.9%. A TiO2/FAS modified superhydrophobic PVDF ENM was fabricated for membrane distillation process, and the manufacture process includes electrospinning, heat-pressing, and dip-coating. The membrane surface properties were investigated via SEM, XPS, and the membrane hydrophobicity was determined based on the apparent contact angle measurement. The superhydrophobic membrane was tested on a bench-scale VMD system, and the results suggested that the membrane was able to effectively treat different feed solutions, and can provide a stable performance.

Keywords: Desalination
Electrospun Nanofiber Membrane
Membrane Bioreactor
Membrane Distillation
Superhydrophobicity
Water and Wastewater Treatment
Advisor: Farnood, Ramin
Tabe, Shahram
Mental Illness Diagnoses After Intensive Care

Background: Survivors of critical illnesses that require intensive care unit (ICU) admission may be at risk of developing new mental illness diagnoses. Methods: Population-based study (2005-2015) of adult ICU survivors in Ontario, Canada, excluding patients with prior mental illness diagnoses. The primary outcome was new mental illness diagnosis during 1-year follow-up, measured using multivariable models that adjusted for potential confounders and the competing risk of death. Results: Overall, the 121,125 patients who survived an ICU admission during the study period had higher adjusted risk of mental illness diagnoses compared to hospitalized controls (HR1.08, 95%CI 1.07-1.10; p

Keywords: intensive care medicine
long-term ICU complications
mental illness
post intensive care syndrome
Advisor: Scales, Damon C
Optimization Application of Acellular Oxidative Potential Measurements to Urban Ambient Particulate Matter

Oxidative potential (OP) and oxidative burden (OB) are emerging metrics for assessing air pollution hazard and risk. Three acellular assays were tested and recommendations were made for standard, reproducible approaches. Standardized practices for choosing analysis concentrations, incorporating standards and controls, and mixing reduced inter-experimental variability and facilitated identification of failed assays. These methods were applied to samples collected from across Toronto, Canada to assess the spatial and seasonal variability in OP and OB of fine particulate matter (PM2.5). OP and OB exhibited greater spatial variability than PM2.5 mass, and OPDTT exhibited greater seasonal variability than PM2.5 mass. Finally, associations between chemical composition and OP suggest that OP may capture the influence of local emissions, such as those from brake wear and road dust. Future work should focus on testing standardized protocols across laboratories to facilitate inter-lab collaborations, and investigating OP associations with a broader suite of chemical species.

Keywords: air quality
exposure
oxidative burden
oxidative potential
particulate matter
urban
Advisor: Evans, Greg J
Plasmodesmatal Density and Cell Wall Architecture Across the C3 to C4 Evolutionary Gradient in Flaveria

High plasmodesmatal density between mesophyll and bundle sheath cells is of importance in C4 plants, where rapid intercellular movement of metabolites is required for efficient operation of C4 photosynthesis. Using the genus Flaveria, I evaluate the hypothesis that plasmodesmatal density gradually increases in C3-C4 intermediate species at the bundle sheath and mesophyll cell interface. Results show that plasmodesmatal density gradually increases as the C4 cycle strengthens in parallel to a reduction in bundle sheath and mesophyll cell contact area. In contrast, absolute number of plasmodesmata does not significantly increase until the C4-like transitional stage. Based on these results, I conclude that plasmodesmatal density gradually increases as a byproduct of other anatomical changes, while elevation of plasmodesmata is punctual, occurring at the C4-like transitional stage.

Keywords: C4 photosynthesis
flaveria
photosynthesis
pitfield
plasmodesmata
transport
Advisor: Sage, Tammy L
Sage, Rowan F
Examining Effects of Early Life Stress and Moderating Influences of Current Life Stress on Reward Processing in Young Adults

This study investigated whether high levels of perceived life stress (Perceived Stress Scale; PSS) moderate the relationship between higher levels of childhood adversity (Childhood Trauma Questionnaire; CTQ) and reduced reward processing functions in a university sample. It was hypothesized that early life adversity and perceived stress would lead to reduced reward sensitivity, measured through performance on the Monetary Incentive Delay Task (MIDT). Further, early life adversity was predicted to reduce motivational behaviours, measured through performance on the Effort Expenditure for Rewards Task (EEfRT). While results did not reveal a significant interaction between childhood adversity and current life stress on reward processes, higher CTQ scores were associated with reduced accuracy in the MIDT. Participants in the high stress group also demonstrated increased reaction times across MIDT trials. There were no significant effects on the EEfRT. These results demonstrate independent associations between early life adversity, current perceived stress, and reduced reward sensitivity.

Keywords: Adversity
Motivation
Reward
Reward processing
Reward sensitivity
Stress
Advisor: Erb, Suzanne
Goghari, Vina