Physical Sciences and Mathematics Commons^™

Towards Parking Lot Occupancy Assessment Using Aerial Imagery And Computer Vision, John Jewell

Electronic Thesis and Dissertation Repository

Advances in Computer Vision and Aerial Imaging have enabled countless downstream applications. To this end, aerial imagery could be leveraged to analyze the usage of parking lots. This would enable retail centres to allocate space better and eliminate the parking oversupply problem. With this use case in mind, the proposed research introduces a novel framework for parking lot occupancy assessments. The framework consists of a pipeline of components that map a sequence of image sets spanning a parking lot at different time intervals to a parking lot turnover heatmap that encodes the frequency each parking stall was used. The pipeline …

Folk Theories, Recommender Systems, And Human-Centered Explainable Artificial Intelligence (Hcxai), Michael Ridley

Electronic Thesis and Dissertation Repository

This study uses folk theories to enhance human-centered “explainable AI” (HCXAI). The complexity and opacity of machine learning has compelled the need for explainability. Consumer services like Amazon, Facebook, TikTok, and Spotify have resulted in machine learning becoming ubiquitous in the everyday lives of the non-expert, lay public. The following research questions inform this study: What are the folk theories of users that explain how a recommender system works? Is there a relationship between the folk theories of users and the principles of HCXAI that would facilitate the development of more transparent and explainable recommender systems? Using the Spotify music …

Advances In The Automatic Detection Of Optimization Opportunities In Computer Programs, Delaram Talaashrafi

Electronic Thesis and Dissertation Repository

Massively parallel and heterogeneous systems together with their APIs have been used for various applications. To achieve high-performance software, the programmer should develop optimized algorithms to maximize the system’s resource utilization. However, designing such algorithms is challenging and time-consuming. Therefore, optimizing compilers are developed to take part in the programmer’s optimization burden. Developing effective optimizing compilers is an active area of research. Specifically, because loop nests are usually the hot spots in a program, their optimization has been the main subject of many optimization algorithms. This thesis aims to improve the scope and applicability of performance optimization algorithms used in …

The Origin And Evolution Of Impact Crater Lakes: A Case Study Of The Ries Impact Structure, Germany, Matthew J. O. Svensson

Electronic Thesis and Dissertation Repository

Impact events are known to generate hydrothermal systems, which can subsequently vent into an overlying crater lake and potentially create ideal conditions for some microbial life-forms. Thus, early post-impact sedimentary deposits would be excellent targets for Mars sample return, and as such, the robust characterization of such deposits on Earth is critical. In this thesis, we establish an improved understanding of how the Ries crater lake formed, and how an active impact-generated hydrothermal system influenced its early evolution. The ~14.8 Ma Ries impact structure hosts the majority of its paleolake deposits within the structure's central basin with some deposits situated …

Algorithmic Improvements In Deep Reinforcement Learning, Norman L. Tasfi

Electronic Thesis and Dissertation Repository

Reinforcement Learning (RL) has seen exponential performance improvements over the past decade, achieving super-human performance across many domains. Deep Reinforcement Learning (DRL), the combination of RL methods with deep neural networks (DNN) as function approximators, has unlocked much of this progress. The path to generalized artificial intelligence (GAI) will depend on deep learning (DL) and RL. However, much work is required before the technology reaches anything resembling GAI. Therefore, this thesis focuses on a subset of areas within RL that require additional research to advance the field, specifically: sample efficiency, planning, and task transfer. The first area, sample efficiency, refers …

Discourse, Power Dynamics, And Risk Amplification In Disaster Risk Management In Canada, Martins Oluwole Olu-Omotayo

Electronic Thesis and Dissertation Repository

The domain of disaster risk management is rife with discursive contentions, whereby dominant discourses amplify the powers of risk actors to precipitate and reinforce political, economic, and environmental inequalities that predispose different sections of the population to unequal disaster risk vulnerabilities. This thesis identified important actors (government, risk experts, media, and NGOs) that shape the power dynamics in disaster risk management in Canada and explained their roles, influences, and the dimensions in which their powers negotiate each other through risk discourses. The patterns of these power dynamics in the three aspects of power –communication, assessment, and social trust –were also …

Multi-Trace Matrix Models From Noncommutative Geometry, Hamed Hessam

Electronic Thesis and Dissertation Repository

Dirac ensembles are finite dimensional real spectral triples where the Dirac operator is allowed to vary within a suitable family of operators and is assumed to be random. The Dirac operator plays the role of a metric on a manifold in the noncommutative geometry context of spectral triples. Thus, integration over the set of Dirac operators within a Dirac ensemble, a crucial aspect of a theory of quantum gravity, is a noncommutative analog of integration over metrics.

Dirac ensembles are closely related to random matrix ensembles. In order to determine properties of specific Dirac ensembles, we use techniques from random …

Synthesis And Surface Modification Of Azide Decorated Silver Nanoclusters, Alexander H. Stöckli

Electronic Thesis and Dissertation Repository

In nanocluster research, easy modification of the cluster surface while maintaining the cluster core remains a key challenge. Herein we report the synthesis, structure, and properties of four targeted Ag₂₀ nanoclusters (NCs) with surface azide moieties, two of which have 8 azide moieties, [CO₃@Ag₂₀(S^tBu)₁₀(m-N₃-C₆H₄COO)₈(DMF)₄] and [CO₃@Ag₂₀(S^tBu)₁₀(p-N₃-C₆H₄COO)₈(DMF)₄], and two of which have 6 azide moieties, [CO₃@Ag₂₀(S …

On The Spatial Modelling Of Biological Invasions, Tedi Ramaj

Electronic Thesis and Dissertation Repository

We investigate problems of biological spatial invasion through the use of spatial modelling. We begin by examining the spread of an invasive weed plant species through a forest by developing a system of partial differential equations (PDEs) involving an invasive weed and a competing native plant species. We find that extinction of the native plant species may be achieved by increasing the carrying capacity of the forest as well as the competition coefficient between the species. We also find that the boundary conditions exert long-term control on the biomass of the invasive weed and hence should be considered when implementing …

Near-Ir Laser Ablation Of Simulated Radiologically Contaminated Oxides On Carbon Steel Feeder Pipes, Thao Viet Do

Electronic Thesis and Dissertation Repository

As nuclear power plants age and retire from service, many countries face significant challenges concerning the safe long-term storage and disposal of large volumes of low and intermediate level radioactive wastes (L&ILW). The volumes of metallic waste are of particular concern, as when metal corrodes it produces hydrogen that could lead to pressure build-up in interim storage and disposal. In Canada, a significant fraction of the metallic wastes for Canada Deuterium Uranium (CANDU) nuclear reactors are out-of-core reactor components, such as carbon steel (CS) feeder pipes. The radioactive contamination is expected to be largely confined to the surface oxide layers …

Three Contributions To The Theory And Practice Of Optimizing Compilers, Linxiao Wang

Electronic Thesis and Dissertation Repository

The theory and practice of optimizing compilers gather techniques that, from input computer programs, aim at generating code making the best use of modern computer hardware. On the theory side, this thesis contributes new results and algorithms in polyhedral geometry. On the practical side, this thesis contributes techniques for the tuning of parameters of programs targeting GPUs. We detailed these two fronts of our work below.

Consider a convex polyhedral set P given by a system of linear inequalities A*x <= b, where A is an integer matrix and b is an integer vector. We are interested in the integer hull P_I of P which is the smallest convex polyhedral set that contains all the integer points in P. In Chapter …

Expanding The Scope Of Clickable Azide-Functionalized Nanoclusters To Include Au144, Johanna A. De Jong

Electronic Thesis and Dissertation Repository

Thiolate-protected Au₁₄₄ nanoclusters (NCs) are an intriguing member of the gold NC family. Their geometric structure, distinct electrochemical features, and susceptibility to structural rearrangement under the duress of ligand exchange have been studied. However, there are currently no established protocols for surface modification or tuning of their ligand shells post synthesis. Here, the direct synthesis of three regioisomers of azide-modified Au₁₄₄ NCs with 60 azide moieties, i.e., Au₁₄₄(SC₂H₄C₆H₄-N₃)₆₀, is reported, in which the azide functionality is located at the ortho-, meta-, or …

The Synthesis, Lewis Acidity And Catalytic Activity Of Bis(Catecholato)Germanes, Andrew T. Henry

Electronic Thesis and Dissertation Repository

Main group Lewis acids have been shown to be viable alternatives to state-of-theart transition metal catalysts. While extensive research into a variety of p-block Lewis acids have been reported, the field of germanium Lewis acid chemistry has been described as “almost non-existent”. A variety of bis(catecholato)germane derivatives have been synthesized. The Lewis acidity of these compounds was analyzed by the Gutmann-Beckett and fluoride ion affinity methods demonstrating the high Lewis acidity of these complexes. The bis(catecholato)germanes were utilized as Lewis acid catalysts for the hydrosilylation of aldehydes, the hydroboration of alkynes, Friedel-Crafts alkylation of alkenes, and the oligomerization of styrene …

Driver Behavior Analysis Based On Real On-Road Driving Data In The Design Of Advanced Driving Assistance Systems, Nima Khairdoost

Electronic Thesis and Dissertation Repository

The number of vehicles on the roads increases every day. According to the National Highway Traffic Safety Administration (NHTSA), the overwhelming majority of serious crashes (over 94 percent) are caused by human error. The broad aim of this research is to develop a driver behavior model using real on-road data in the design of Advanced Driving Assistance Systems (ADASs). For several decades, these systems have been a focus of many researchers and vehicle manufacturers in order to increase vehicle and road safety and assist drivers in different driving situations. Some studies have concentrated on drivers as the main actor in …

Developing Carbon Quantum Dots As A Luminescent Material And Revisiting Ecl And Led Absolute Measurement Methods, Jonathan Ralph Adsetts

Electronic Thesis and Dissertation Repository

Luminescent materials play increasingly important roles in our lives. Improvements in these materials’ quantum efficiencies (QEs), costs and toxicity can greatly reduce the power consumption, price and environmental damage to the planet, respectively. Carbon quantum dots (CQDs) and luminescent materials exhibiting thermally activated delayed fluorescence (TADF) are two interesting materials in these aspects. Furthermore, measurements on electrochemiluminescence (ECL) and electroluminescence of these luminescent materials can quickly evaluate their performance for many applications. In this thesis, controlled CQD syntheses are revealed beneficial to luminescent materials applications. Their film ECL demonstrated relatively stable anionic and cationic radicals leading to high emission at …

Portfolio Optimization Analysis In The Family Of 4/2 Stochastic Volatility Models, Yuyang Cheng

Electronic Thesis and Dissertation Repository

Over the last two decades, trading of financial derivatives has increased significantly along with richer and more complex behaviour/traits on the underlying assets. The need for more advanced models to capture traits and behaviour of risky assets is crucial. In this spirit, the state-of-the-art 4/2 stochastic volatility model was recently proposed by Grasselli in 2017 and has gained great attention ever since. The 4/2 model is a superposition of a Heston (1/2) component and a 3/2 component, which is shown to be able to eliminate the limitations of these two individual models, bringing the best out of each other. Based …

Conformational Dynamics And Aggregation Of Thermally Stressed Proteins Studied By Hydrogen/Deuterium Exchange Mass Spectrometry, Nastaran Nosrat Tajoddin

Electronic Thesis and Dissertation Repository

Proteins perform various biological functions, e.g., as enzymes or transporters. In addition to naturally occurring proteins, the use of protein therapeutic drugs for treating cancer and other diseases is a rapidly growing area. A thorough biophysical characterization of proteins and protein therapeutics opens the door to a more comprehensive understanding of their role in health and disease. This dissertation aims to expand the capabilities of an existing technique (Hydrogen Deuterium Exchange Mass Spectrometry, HDX-MS), which is widely used for probing protein structure and dynamics. Conventionally, HDX-MS experiments are performed as a function of labelling time. Here we aim to establish …

Approaches To Model Non-Uniqueness And Site Complexity For Non-Invasive Shear-Wave Depth Profiling, Christopher Boucher

Electronic Thesis and Dissertation Repository

Shear-wave velocity (VS) depth profiling and associated seismic site classifications were performed at 15 sites across Metro Vancouver, British Columbia using passive seismic and surface wave methods. Inversion model parameters are constrained at each site using nearby geodata in combination with developing regression models of shear-wave velocity with depth for three primary stratigraphic units. Statistical methods such as a Bayesian Information Criterion are applied post-inversion to evaluate models between and within varying parameterizations. Data evaluation metrics, including the use of microtremor horizontal-to-vertical spectral ratios (MHVSRs), are applied to identify two common deviations from the simple case of normally dispersive laterally …

The Spectro-Temporal Relationships Of Repeating Fast Radio Bursts, Mohammed Afif Chamma

Electronic Thesis and Dissertation Repository

Fast radio bursts (FRBs) are short and extremely energetic bursts of radiation detected from galaxies across the universe that occur thousands of times a day. Despite advances in instrumentation, it is difficult to explain the enormous implied energy reservoirs of FRBs, their emission mechanism and the existence of repeating and periodic sources. This thesis explores the spectro-temporal properties of repeating FRBs and details the discovery of several new relationships between them, providing valuable information on the nature of FRBs. By measuring the spectro-temporal properties of a sample of bursts from the repeating source FRB20121102A I show that the magnitude of …

Subsurface Correlation Of Lower Silurian Medina Group, Southwestern Ontario, Rhys H. Paterson

Electronic Thesis and Dissertation Repository

The Medina Group succession in southwestern Ontario includes, in ascending order: the Whirlpool, Manitoulin, Cabot Head, Power Glen, Devils Hole-Balls Falls, Grimsby, and Thorold formations. Subsurface mapping in central and eastern Lake Erie has resulted in the recognition of three stratigraphic packages within the Medina Group based upon the integration of sedimentologic, stratigraphic and geophysical borehole logs. The interplay between changing paleoenvironments, sediment provenance, and regional tectonics and associated sea level fluctuations has resulted in the accumulation of a complex mosaic of mixed siliciclastics and carbonates. Manitoulin Formation carbonates and Whirlpool Formation siliciclastics display consistent thicknesses across the study area. …

The Coordination Chemistry And Reactivity Of Pd Phosphine 1-Azaallyl Complexes, Kyle M. Jackman

Electronic Thesis and Dissertation Repository

Structurally responsive ligands (SRLs) are a class of ligands that change their coordination mode with a metal centre, which permits reactions that are difficult with non-SRLs, allow access to unique mechanisms, and allow isolation of unusual coordination complexes. The 1-azaallyl (1-AzA) family of SRLs are capable of isomerizing between η³-NCC and κ¹-N modes that occupy two and one coordination sites, respectively. This thesis investigates a new class of phosphine 1^AzA (P^AzA) ligands and the reactivity of their coordination complexes with palladium.

The first-generation P^AzA ligand contains a phenyl linkage between the two heteroatoms and affords a …

An Investigation Into Time Gazed At Traffic Objects By Drivers, Kolby R. Sarson

Electronic Thesis and Dissertation Repository

Several studies have considered driver’s attention for a multitude of distinct purposes, ranging from the analysis of a driver’s gaze and perception, to possible use in Advanced Driving Assistance Systems (ADAS). These works typically rely on simple definitions of what it means to “see,” considering a driver gazing upon an object for a single frame as being seen. In this work, we bolster this definition by introducing the concept of time. We consider a definition of ”seen” which requires an object to be gazed upon for a set length of time, or frames, before it can be considered as seen …

Characterization Of 1d And 2d Materials With Tip-Enhanced Raman Spectroscopy, María Olivia Avilés

Electronic Thesis and Dissertation Repository

Carbon-based materials, such as 1D single-walled carbon nanotubes (SWCNT) or 2D graphene, are promising materials for a variety of applications in energy storage, biosensors, and medical imaging applications. Similarly, beyond graphene, 2D transition metal dichalcogenides (TDM) that can have either a metallic or semiconducting character have gained interest for potential applications in electronics and photonics. Specifically, metallic TMDs such as vanadium disulfide (VS₂) show potential applications in optoelectronics and lithium-ion batteries. On the other hand, semiconducting TDMs like tungsten disulfide (WS₂) show a direct band gap, making them interesting for photovoltaic applications, transistors, or photodetectors. The …

Potential Of Vision Transformers For Advanced Driver-Assistance Systems: An Evaluative Approach, Andrew Katoch

Electronic Thesis and Dissertation Repository

In this thesis, we examine the performance of Vision Transformers concerning the current state of Advanced Driving Assistance Systems (ADAS). We explore the Vision Transformer model and its variants on the problems of vehicle computer vision. Vision transformers show performance competitive to convolutional neural networks but require much more training data. Vision transformers are also more robust to image permutations than CNNs. Additionally, Vision Transformers have a lower pre-training compute cost but can overfit on smaller datasets more easily than CNNs. Thus we apply this knowledge to tune Vision transformers on ADAS image datasets, including general traffic objects, vehicles, traffic …

Statistical Roles Of The G-Expectation Framework In Model Uncertainty: The Semi-G-Structure As A Stepping Stone, Yifan Li

Electronic Thesis and Dissertation Repository

The G-expectation framework is a generalization of the classical probability system based on the sublinear expectation to deal with phenomena that cannot be described by a single probabilistic model. These phenomena are closely related to the long-existing concern about model uncertainty in statistics. However, the distributions and independence in the G-framework are quite different from the classical setup. These distinctions bring difficulty when applying the idea of this framework to general statistical practice. Therefore, a fundamental and unavoidable problem is how to better understand G-version concepts from a statistical perspective.

To explore this problem, this thesis establishes a new substructure …

Investigating The Mechanism Of Protein And Peptide Electrospray Ionization, Elnaz Aliyari

Electronic Thesis and Dissertation Repository

Electrospray ionization (ESI) mass spectrometry (MS) is widely used for the detection and characterization of various analytes. However, many fundamental aspects of the ESI process remain poorly understood. Using molecular dynamics (MD) simulations, MS, and ion mobility spectrometry (IMS), this thesis sheds light on the mechanisms whereby gaseous analyte ions are formed from highly charged ESI nanodroplets. After a general introduction (Chapter 1), Chapter 2 focuses on the ion evaporation mechanism (IEM), i.e., the ejection of analyte ions from the droplet surface. The IEM is well established for low MW compounds, but it has remained contentious whether this pathway is …

Extracting Microservice Dependencies Using Log Analysis, Andres O. Rodriguez Ishida

Electronic Thesis and Dissertation Repository

Microservice architecture is an architectural style that supports the design and implementation of very scalable systems by distributing complex functionality to highly granular components. These highly granular components are referred to as microservices and can be dynamically deployed on Docker containers. These microservice architecture systems are very extensible since new microservices can be added or replaced as the system evolves. In such highly granular architectures, a major challenge that arises is how to quickly identify whether any changes in the system’s structure violate any policies or design constraints. Examples of policies and design constraints include whether a microservice can call …

Pressure-Induced Modifications To The Structural And Optoelectronic Properties Of 2d Hybrid Organic-Inorganic Perovskites, Jesse Ratte

Electronic Thesis and Dissertation Repository

Recently, 2D hybrid organic-inorganic perovskites (HOIP) have garnered lots of research interest for their applications in optoelectronic devices, especially in solar cells. The optoelectronic properties of 2D HOIPs have yet to be optimized for these applications. High external pressure is well known to induce structural modifications to 2D HOIPs, and thus modify their optoelectronic properties. Herein, we report a study of the effects of high pressure (HP) on the structures and optoelectronic properties of cyclohexane methylamine (CMA) lead iodide (CMA2PbI4) and the structures of N,N-dimethylphenylene-p-diammonium (DPDA) lead iodide (DPDAPbI4).

High pressure measurements of CMA2PbI4 were performed using Raman spectroscopy, Fourier-transform …

Natural Product Discovery And Mycotoxin Analysis Of Agricultural Endophytes And Pathogens, Jacob P. Walsh

Electronic Thesis and Dissertation Repository

This thesis focuses on the application of fungal natural product chemistry for the use of agriculture fungal pathogenesis research. The research in this work uses many analytical chemistry techniques and instruments such as HPLC, LC-MS/MS and NMR. In Chapter 2, a diagnostic fragmentation module was developed for the identification of compound classes in crude fungal extracts. This module identified the classes cytochalasins and chaetoglobosins from extracts of Penicillium, Chaetomium, and Xylaria. From these extracts a new chaetoglobosin was discovered and the module was implemented into the open-source software package MZmine 2.0. Chapter 3 discusses analytical chemistry techniques with the …

Regression-Based Methods For Dynamic Treatment Regimes With Mismeasured Covariates Or Misclassified Response, Dan Liu

Electronic Thesis and Dissertation Repository

The statistical study of dynamic treatment regimes (DTRs) focuses on estimating sequential treatment decision rules tailored to patient-level information across multiple stages of intervention. Regression-based methods in DTR have been studied in the literature with a critical assumption that all the observed variables are precisely measured. However, this assumption is often violated in many applications. One example is the STAR*D study, in which the patient's depressive score is subject to measurement error. In this thesis, we explore problems in the context of DTR with measurement error or misclassification considered in the observed data.

The first project deals with covariate measurement …