Physical Sciences and Mathematics Commons^™

The Physical Properties Of Volcanic And Impact Melt, Gavin Douglas Tolometti

Electronic Thesis and Dissertation Repository

The emplacement mechanisms of lunar impact melt flows, that form from hypervelocity impact events, have been a subject of debate in the lunar science community, because of their unique physical properties that separate them from other geologic features. Understanding how lunar impact melt flows were emplaced on the surface of the Moon will not only grant us new information about the flow dynamics of impact melt but provide insight into the production and distribution of impact melt and how it built and modified the surfaces of planetary surfaces.

Lunar impact melt flows exhibit surface roughness textures and morphologies that are …

Cubical Models Of Higher Categories, Brandon Doherty

Electronic Thesis and Dissertation Repository

This thesis concerns model structures on presheaf categories, modeling the theory of infinity-categories. We introduce the categories of simplicial and cubical sets, and review established examples of model structures on these categories for infinity-groupoids and (infinity, 1)-categories, including the Quillen and Joyal model structures on simplicial sets, and the Grothendieck model structure on cubical sets. We also review the complicial model structure on marked simplicial sets, which presents the theory of (infinity, n)-categories. We then construct a model structure on the category of cubical sets whose cofibrations are the monomor- phisms and whose fibrant objects are defined by the right …

Investigation Of Shocked Basalts From Vargeão Dome And Vista Alegre: Implications For The Search For Life On Mars, Nikol Posnov

Electronic Thesis and Dissertation Repository

Impact craters represent excellent astrobiological targets for planetary exploration missions to Mars. The impact of an asteroid or comet into a crystalline, H₂O-bearing target may result in development of a hydrothermal system and increase the habitability of the substrate for the colonization of endolithic microorganisms. Given that Mars’ surface is covered by cratered basaltic rock, this study investigated target rocks and impact breccias from Vargeão Dome and Vista Alegre impact structures that formed in basalt in the Paraná Basin of Brazil.

Utilizing petrography and micro-X-ray diffraction (μXRD), the degree of shock metamorphism in plagioclase was quantitively determined. Measuring …

Nature, Nurture, Or Both? Study Of Sex And Gender And Their Effects On Pain, Maryam Ghodrati

Electronic Thesis and Dissertation Repository

As a pain researcher, in order to have a better understanding of pain, we should adopt a multidimensional view, such as the biopsychosocial (BPS) model and consider physical, psychological, and social elements altogether. The studies in this dissertation are part of the bigger project of SYMBIOME in which the aim is to help to create and develop a prognostic clinical phenotype in people post musculoskeletal (MSK) trauma. Chapter 2 presents a Confirmatory Factor Analysis (CFA) in order to assess the structural validity of the first section of the new Gender Pain and Expectation Scale (GPES). Our analysis indicated a 3-factor …

Nanoorthogonal Surface Modifications Of Gold Nanoparticles And Nanoclusters Through Strain-Promoted Cycloaddition Chemistry, Praveen N. Gunawardene

Electronic Thesis and Dissertation Repository

This thesis explores the preparation of thiolated gold nanoparticles (AuNPs) and thiolated gold nanoclusters (AuNCs) capable of undergoing post-assembly surface modifications using two common “bioorthogonal” click reactions: the strain-promoted alkyne-azide cycloaddition (SPAAC) reaction (which occurs between a strained-alkyne and an azide) and the strain-promoted alkyne-nitrone cycloaddition (SPANC) reaction (which occurs between a strained-alkyne and a nitrone). Due to their rapid and modifiable reaction kinetics, high chemoselectivity, and stability of the reactive partners, these reactions were originally designed to tether functional substrates to biologically sensitive biomolecules, without altering their structure or perturb the biologically sensitive environments in which they …

Fuzzy And Probabilistic Rule-Based Approaches To Identify Fault Prone Files, Piyush Kumar Korlepara

Electronic Thesis and Dissertation Repository

Most software fault proneness prediction techniques utilize machine learning models which act as black boxes when performing predictions. Software developers cannot obtain any insights as to why such trained models reached their conclusions when applied to new data. This leads to a reduced confidence in accepting the prediction results while applying the model in complex systems. In this thesis, we propose two rule-based and programming language-agnostic fault proneness prediction techniques. The first technique utilizes fuzzy reasoning, while the second utilizes Markov Logic Networks. The rules operate on facts that are produced by harvesting and postprocessing raw data extracted from the …

On The Estimation Of Heston-Nandi Garch Using Returns And/Or Options: A Simulation-Based Approach, Xize Ye

Electronic Thesis and Dissertation Repository

In this thesis, the Heston-Nandi GARCH(1,1) (henceforth, HN-GARCH) option pricing model is fitted via 4 maximum likelihood-based estimation and calibration approaches using simulated returns and/or options. The purpose is to examine the benefits of the joint estimation using both returns and options over the fundamental returns-only estimation on GARCH models. From our empirical studies, with the additional option sample, we can improve the efficiency of the estimates for HN-GARCH parameters. Nonetheless, the improvements for the risk premium factor, both from empirical standard errors, and sample RMSEs, are insignificant. In addition, option prices are simulated with a pre-defined noise structure and …

Seismic Imaging In Crystalline Terrains Of The Superior Province, Canada, Brian Villamizar

Electronic Thesis and Dissertation Repository

The imaging of structures in sedimentary basins has typically been carried out using conventional seismic reflection techniques. In complex geological architectures, such as those within the Superior Province in Canada, conventional seismic imaging yields suboptimal results due to factors stemming from complex energy scattering and crooked seismic geometries. Full-waveform inversion (FWI) is a nonlinear inverse technique capable of retrieving quantitative images of velocity structures. Judicious data preconditioning, and multiscale inversion strategies allow FWI to effectively estimate velocity variations in the first few kilometers of the subsurface. Non-conventional seismic reflection processing, based on azimuthal binning and enhanced migration velocity models, improves …

The Analysis Of Ginsenosides In Ginseng Garden Soil, Karina Marie Kaberi

Electronic Thesis and Dissertation Repository

American ginseng (Panax quinquefolius L.) produces natural products called ginsenosides. The biggest challenge Ontario commercial ginseng farmers face is ginseng replant disease. To understand the function of ginseng root exudates, ginsenoside accumulation and persistence over time were investigated. Currently, no reliable ginsenoside specific extraction method, characterizing the changes in soil chemistry exists. Ginsenoside extraction protocol optimization was required to determine how ginsenoside composition changed over time. Overall, protocol optimization resulted in a 30% increase in yield of ginsenosides compared to previous extraction protocols. In the ginseng gardens, ginsenoside accumulation occurs slowly and did not reach significantly measurable amounts until the …

Predicting Stock Market Sector Sentiment Through News Article Based Textual Analysis, William A. Beldman

Electronic Thesis and Dissertation Repository

Investors seek to take advantage of computer technology to gain an edge on their investments. This can be done through quantitative (historical number-based) analysis or qualitative (natural language-based) analysis. Subject matter experts have been known to make predictions between 70 and 79% accuracy at best and less than 50% accuracy on average. Sophisticated algorithms through qualitative analysis are known to demonstrate more successful market predictions for specific stocks. It stands to reason that the same technique could work just as well or better for attempting to predict entire sectors of the stock market. By using indices and exchange traded funds, …

Addressing Bias In Non-Experimental Studies Assessing Treatment Outcomes In Prostate Cancer, David E. Guy

Electronic Thesis and Dissertation Repository

We evaluated the ability of matching techniques to balance baseline characteristics between treatment groups using non-experimental data. We identified a set of balance diagnostics that assessed key differences in baseline covariates with potential for confounding. These diagnostics were used in a novel systematic approach to developing and evaluating models for use in propensity score matching that optimized balance and data retention. We then compared the performance of propensity score and coarsened exact matching strategies in optimizing balance and data retention, using non-experimental data from a pan-Canadian prostate cancer database. Both matching techniques balanced baseline covariates adequately and retained approximately 70% …

Copper Corrosion Dynamics Under Deep Geologic Repository Conditions, Masoumeh Naghizadeh

Electronic Thesis and Dissertation Repository

Canada’s plan for the permanent disposal of spent nuclear fuel involves a multiple-barrier system contained within a deep geologic repository (DGR). The key engineered barrier is the used fuel container (UFC), which is a copper-coated carbon steel vessel. The environments to which the copper coating will be exposed in the DGR are very different from those commonly encountered in copper corrosion studies. The copper (Cu) will be in contact with thin stagnant layers of water, and the corrosion system will be exposed to a continuous flux of γ-radiation. In the presence of γ-radiation, water and humid air decompose to redox-active …

Analysis And Differentiation Of Uniform And Localized Corrosion Of Cu, Roshan J. Daljeet

Electronic Thesis and Dissertation Repository

The current plan for disposal of used nuclear fuel in Canada involves sealing the waste in steel containers coated with 3 mm of copper and burying them in a deep geologic repository (DGR). The purpose of the copper coating is to provide corrosion resistance. To achieve long term containment, it is necessary that the copper layer corrodes slowly and predictably via active dissolution rather than passivating due to film formation. Film formation could allow pitting corrosion to occur in early phase repository conditions when groundwater ions such as Cl– , SO4 2– and HCO3 – play a dominant role in …

Organic Geochemistry, Organic Petrography And Basin Modelling Of The Upper Cretaceous Second White Specks And Upper Belle Fourche Alloformations In The Western Canada Foreland Basin, Mailyng Angelica Aviles

Electronic Thesis and Dissertation Repository

The Second White Specks is an unconventional shale play in the Western Canada Foreland Basin, endowed with over 450 billion barrels of light oil in place. Inconsistent production performance, however, has hindered its economic viability as a resource play. One potential explanation for erratic production behavior, on local and regional scales, is heterogeneous distribution of retained oil charge in the source rock. This study focuses on the analysis of geochemical properties and thermal history of the organic matter to assess lateral variability in generated hydrocarbon in the Second White Specks.

The methodology comprised characterization of the organic matter integrating organic …

Cationic Boron Formazanate Complexes, Benjamin D. Katzman

Electronic Thesis and Dissertation Repository

This thesis describes the synthesis and characterization of various three- and four-coordinate cationic and dicationic boron complexes supported by formazanate ([R₁-N-N=C(Ph)-N=N-R₅]⁻ ligands. The first chapter provides a review of various three-coordinate and cationic boron complexes and related applications. Chapter two examines the effect of several variations (i.e., charge, coordination number and boron-bound substituents) on the electronic structure of cationic boron formazanate complexes. Absorption spectroscopy measurements reveal that the wavelengths, intensities, and type of the first electronic transitions in cationic boron complexes can be modulated by these structural variations. Chapter three exploits the electron deficiency …

Mathematical Modelling & Simulation Of Large And Small Scale Structures In Star Formation, Gianfranco Bino

Electronic Thesis and Dissertation Repository

This thesis aims to study the magnetic and evolutionary properties of stellar objects from the prestellar phase up to and including the late protostellar phase. Many of the properties governing star formation are linked to the core’s physical properties and the magnetic field highly dictates much of the core’s stability.

The thesis begins with the implementation of a fully analytic magnetic field model used to study the magnetic properties governing the prestellar core FeSt 1-457. The model is a direct result of Maxwell’s equations and yields a central-to-surface magnetic field ratio in the equatorial plane in cylindrical coordinates. The model …

Making Sense Of Noisy Data: Theory And Applications, Lingzhi Chen

Electronic Thesis and Dissertation Repository

This thesis introduces a novel and interpretable index of increase which is mathematically defined based on the distance between a given function and a set of non-increasing functions. Unlike the widely used traditional statistical methods for analyzing relationships between variables, the index does not rely on assumptions such as linearity, normality, and monotonicity, which may not be satisfied. Hence, it has the flexibility to be applied directly on pairs of data points to measure and compare non-linear, asymmetric, and non-monotonic relationships between two variables.

We begin with a review of the literature and background knowledge in Chapter 2.

In Chapter …

Sample Size Formulas For Estimating Areas Under The Receiver Operating Characteristic Curves With Precision And Assurance, Grace Lu

Electronic Thesis and Dissertation Repository

The area under the receiver operating characteristic curve (AUC) is commonly used to quantify the discriminative ability of tests with ordinal or continuous test data. When planning a study to evaluate a new test, it is important to determine a minimum sample size required to achieve a prespecified precision of estimating AUC. However, conventional sample size formulas do not consider the probability of achieving a prespecified precision, resulting in underestimation of sample sizes. To incorporate the assurance probability, asymptotic sample size formulas were derived using different variance estimators for AUC in this thesis. The precision of AUC estimations was quantified …

Field Theories From Physical Requirements: Noether's First Theorem, Energy-Momentum Tensors And The Question Of Uniqueness, Mark Robert Baker

Electronic Thesis and Dissertation Repository

An axiomatic approach to physics is proposed for obtaining classical gauge theories from a common set of physical requirements based on standard features of special relativistic field theories such as gauge invariance, conformal invariance and being in four dimensions. This approach involves the use of Noether's first theorem to directly obtain a unique, complete set of equations from the symmetries of the action. However, implementation of this procedure is obstructed by issues of ambiguity and non-uniqueness associated with the conserved tensors in the majority of special relativistic field theories. In the introductory chapter, we outline the three major problems which …

Improving Reader Motivation With Machine Learning, Tanner A. Bohn

Electronic Thesis and Dissertation Repository

This thesis focuses on the problem of increasing reading motivation with machine learning (ML). The act of reading is central to modern human life, and there is much to be gained by improving the reading experience. For example, the internal reading motivation of students, especially their interest and enjoyment in reading, are important factors in their academic success.

There are many topics in natural language processing (NLP) which can be applied to improving the reading experience in terms of readability, comprehension, reading speed, motivation, etc. Such topics include personalized recommendation, headline optimization, text simplification, and many others. However, to the …

Generating Effective Sentence Representations: Deep Learning And Reinforcement Learning Approaches, Mahtab Ahmed

Electronic Thesis and Dissertation Repository

Natural language processing (NLP) is one of the most important technologies of the information age. Understanding complex language utterances is also a crucial part of artificial intelligence. Many Natural Language applications are powered by machine learning models performing a large variety of underlying tasks. Recently, deep learning approaches have obtained very high performance across many NLP tasks. In order to achieve this high level of performance, it is crucial for computers to have an appropriate representation of sentences. The tasks addressed in the thesis are best approached having shallow semantic representations. These representations are vectors that are then embedded in …

An Assessment Of The Spatial And Temporal Distribution Of Microplastics In Surface And Subsurface Sediment Of Lake Huron, North America, Sara L. Belontz

Electronic Thesis and Dissertation Repository

The awareness of and the data on the prevalence of microplastic (plastic particles <5mm) pollution in freshwater environments is rapidly increasing, as low-degrading polymers are being detected in various environmental matrices of the Laurentian Great Lakes. However, the accumulation, distribution and deposition of microplastics in offshore depositional environments of the Great Lakes, and particularly Lake Huron, is relatively unknown. In this study, benthic sediment from various Lake Huron waterbodies (main basin, Georgian Bay, the North Channel, and Saginaw Bay) was quantified for microplastic particles (fibres, fragments, films, and beads). The North Channel contained the greatest microplastic abundances, averaging 47,398 particles per kg^-1 dry weight sediment (p kg^-1 dw), followed by Georgian Bay (21,390 p kg^-1 dw), the main basin (15,910 p kg^-1 dw) and Saginaw Bay (1,592 p kg^-1 dw). The results suggest that microplastic abundances in offshore settings are positively correlated with increasing water depth (p=0.004) and are controlled by lake bottom geomorphology. Hydrodynamic processes are a prevailing force driving microplastic dispersion and deposition into the offshore, in contrast to source-based drivers closer to the shoreline. Sediment cores were examined from …

A Class Of Phase-Type Ageing Models And Their Lifetime Distributions, Boquan Cheng

Electronic Thesis and Dissertation Repository

Ageing is a universal and ever-present biological phenomenon. Yet, describing the ageing mechanism in formal mathematical terms — in particular, capturing the ageing pattern and quantifying the ageing rate — has remained a challenging actuarial modelling endeavour. In this thesis, we propose a class of Coxian-type Markovian models. This class enables a quantitative description of the well-known characteristics of ageing, which is a genetically determined, progressive, and essentially irreversible process. The unique structure of our model features the transition rate for the ageing process and a functional form for the relationship between ageing and death with a shape parameter that …

A Lightweight And Explainable Citation Recommendation System, Juncheng Yin

Electronic Thesis and Dissertation Repository

The increased pressure of publications makes it more and more difficult for researchers to find appropriate papers to cite quickly and accurately. Context-aware citation recommendation, which can provide users suggestions mainly based on local citation contexts, has been shown to be helpful to alleviate this problem. However, previous works mainly use RNN models and their variance, which tend to be highly complicated with heavy-weight computation. In this paper, we propose a lightweight and explainable model that is quick to train and obtains high performance. Our model is based on a pre-trained sentence embedding model and trained with triplet loss. Quantitative …

The Development Of Fluorine-18 Imaging Agents Targeting The Ghsr, Marina D. Childs

Electronic Thesis and Dissertation Repository

Molecular imaging is an interdisciplinary field of study that allows for real-time visualization of biological processes in both healthy and disease states. Fluorine-18 positron emission tomography (PET) imaging is a highly sensitive technique where molecular probes containing fluorine-18 serve to specifically locate and visualize the expression of relevant disease biomarkers. The growth hormone secretagogue receptor 1a (GHSR) is differentially expressed in cancer and cardiac pathology, making it a biomarker of interest for imaging such diseases. This thesis discusses the development and optimization of GHSR-targeting ¹⁸F-PET imaging probes as well as proposes a new imaging agent discovery technique.

Chapter 2 …

Protein Interaction Sites Prediction Using Deep Learning, Sourajit Basak

Electronic Thesis and Dissertation Repository

The accurate prediction of protein-protein interaction (PPI) binding sites is a fundamental problem in bioinformatics, since most of the time proteins perform their functions by interacting with some other proteins. Experimental methods are slow, expensive and not very accurate, hence the need for efficient computational methods.

In this thesis, we perform a study aiming to improve the performance of the currently best program for binding site prediction, DELPHI. We have employed some of the currently best techniques from machine learning, including attention and various embedding techniques, such as BERT and ELMo. This is the first time such tools are being …

Population And Evolution Dynamics In Predator-Prey Systems With Anti-Predation Responses, Yang Wang

Electronic Thesis and Dissertation Repository

This thesis studies the impact of anti-predation strategy on the population dynamics of predator-prey interactions. This work includes three research projects.

In the first project, we study a system of delay differential equations by considering both benefit and cost of anti-predation response, as well as a time delay in the transfer of biomass from the prey to the predator after predation. We reveal some insights on how the anti-predation response level and the biomass transfer delay jointly affect the population dynamics; we also show how the nonlinearity in the predation term mediated by the fear effect affects the long term …

Calibration Between Eye Tracker And Stereoscopic Vision System Employing A Linear Closed-Form Perspective-N-Point (Pnp) Algorithm, Mohammad Karami

Electronic Thesis and Dissertation Repository

In many advanced driver assistance systems (ADAS) applications, it is essential to figure out where gaze of driver locates in image area of stereoscopic vision system. This problem, which involves a cross calibration between the stereo vision system and eye tracker, is a challenging task since the two systems are not consistent in modality and do not share a common image area. The eye tracker system provides a 3D gaze vector which describes the direction of driver’s 3D line of gaze, while the stereoscopic vision system provides a depth image frame. In this thesis, this crosscalibration was performed with a …

Geological, Mineralogical And Geochemical Process Controls On Ni Tenor Variations In The Metasedimentary-Hosted Thompson 1d Orebody At Vale’S Thompson Mine (T3), Northern Manitoba, Canada, Povilas G. Grigutis

Electronic Thesis and Dissertation Repository

The Proterozoic Thompson Nickel Belt (TNB) contains rift-related mafic-ultramafic igneous rocks, in a collisional belt at the NW margin of the Archean Superior province in Northern Manitoba, Canada. The TNB hosts world class Ni-Cu-(PGE) mineralization, that has undergone polyphase deformation (D₁ – D₄) and upper amphibolite to lower granulite facies metamorphism, up to ~750ºC and 7.5 kbars (Lightfoot et al., 2017). Komatiitic magmas (1880 ± 5 Ma; Hulbert et al., 2005) fertile in Ni & PGE elements intruded Ospwagan Group metasedimentary sequences and through sulfur assimilation and segregation produced primary magmatic sulfides (Lesher and Burnham, 2001).

The …

Formation Of Supermassive Black Holes In The Early Universe, Arpan Das

Electronic Thesis and Dissertation Repository

The aim of the work presented in this thesis is to understand the formation and growth of the seeds of the supermassive black holes in early universe. Supermassive black holes (SMBH) with masses larger than 10⁸M_Sun have been observed when the Universe was only 800 Myr old. The formation and accretion history of the seeds of these supermassive black holes are a matter of debate. We consider the scenario of massive seed black hole formation which allows gas to directly collapse into a black hole (DCBH) of similar mass. Considering this scenario, we show that the mass …