Physical Sciences and Mathematics Commons^™

Kohn–Sham Exchange-Correlation Potentials From Second-Order Reduced Density Matrices, Rogelio Cuevas-Saavedra, Paul W. Ayers, Viktor N. Staroverov

Chemistry Publications

We describe a practical algorithm for constructing the Kohn–Sham exchange-correlation potential corresponding to a given second-order reduced density matrix. Unlike conventional Kohn–Sham inversion methods in which such potentials are extracted from ground-state electron densities, the proposed technique delivers unambiguous results in finite basis sets. The approach can also be used to separate approximately the exchange and correlation potentials for a many-electron system for which the reduced density matrix is known. The algorithm is implemented for configuration-interaction wave functions and its performance is illustrated with numerical examples.

Vascular Tree Structure: Fast Curvature Regularization And Validation, Egor Chesakov

Electronic Thesis and Dissertation Repository

This work addresses the challenging problem of accurate vessel structure analysis in high resolution 3D biomedical images. Typical segmentation methods fail on recent micro-CT data sets resolving near-capillary vessels due to limitations of standard first-order regularization models. While regularization is needed to address noise and partial volume issues in the data, we argue that extraction of thin tubular structures requires higher-order curvature-based regularization. There are no standard segmentation methods regularizing surface curvature in 3D that could be applied to large 3D volumes. However, we observe that standard measures for vessels structure are more concerned with topology, bifurcation angles, and other …

Recent Discoveries In The Ni-Cu-Pge Bearing Trill And Parkin Offset Dykes, Sudbury Impact Structure, Canada, Adam B. Coulter

Electronic Thesis and Dissertation Repository

The Sudbury structure hosts world class Ni-Cu-PGE deposits that have been mined, explored and studied for over 130 years. The structure is widely recognized as the erosional remnant of a 1.85 Ga 200- to 250-km tectonically altered multi-ring impact basin located in central Ontario, Canada. The focus of this investigation is on the Trill and Parkin Offset dykes. This study provides updated regional scale geologic maps, detailed geologic maps of newly exposed sections, geochemistry, sulphide analysis and an analysis of the inclusion population and orientation within the dykes. We conclude, the dyke phases display remarkable geochemical homogeneity, the Ni-Cu-PGE mineralization …

The Effects Of Warming Temperatures, Fire, And Landscape Change On Lake Production In Mountain Lakes, Alberta, Canada, Amber Elizabeth Gall

Electronic Thesis and Dissertation Repository

Many factors could be causing the widespread eutrophication being observed globally, including natural and human factors. In the mountainous regions of Alberta, Canada, warming temperatures, increased fire occurrence, and greater landscape disturbance could increase lake production. To determine the effects of these factors, proxies of lake production preserved in lake sediment records that span the last 1000 years were measured. These records are from two lakes that have not been affected by direct nutrient inputs from human activities; one in Jasper National Park and one from the Hinton area (Alberta). The results highlight that there is little effect of fire …

On Calculating The Current-Voltage Characteristic Of Multi-Diode Models For Organic Solar Cells, Ken Roberts, Sree Ram Valluri

Physics and Astronomy Publications

We provide an alternative formulation of the exact calculation of the current-voltage characteristic of solar cells which have been modeled with a lumped parameters equivalent circuit with one or two diodes. Such models, for instance, are suitable for describing organic solar cells whose current-voltage characteristic curve has an inflection point, also known as an S-shaped anomaly. Our formulation avoids the risk of numerical overflow in the calculation. It is suitable for implementation in Fortran, C or on micro-controllers.

The Mistastin Lake Impact Structure As A Terrestrial Analogue Site For Lunar Science And Exploration, Marianne M. Mader

Electronic Thesis and Dissertation Repository

The impact cratering record on the Moon is important for many reasons, from understanding early solar system chronology to probing the lunar interior. In order to maximize scientific return from future lunar missions, it is useful to: 1) study terrestrial impact craters to better understand impact processes and products, and 2) develop appropriate human and robotic exploration strategies aligned with geological goals.

This research shows that the intermediate-size Mistastin Lake impact structure, in northern Labrador, Canada, is an unparalleled lunar analogue site, which includes both an anorthositic target and an almost complete suite of impact lithologies, including proximal ejecta deposits. …

Vibrational Imaging At The Nanoscale: Surpassing The Diffraction Limit Using Tip-Enhanced Raman Spectroscopy, Farshid Pashaee

Electronic Thesis and Dissertation Repository

A deep understanding of the chemical composition of surfaces, interfaces or nanoscale structure with a high spatial resolution is an important goal in nanoscience and nanotechnology. Structural information can be collected using a variety of high spatial resolution techniques such as atomic force microscopy (AFM), scanning tunneling microscopy (STM), scanning electron microscopy (SEM), or transmission electron microscopy (TEM). Nevertheless, these methods do not offer molecular information such as vibrational spectroscopy techniques that allow one to collect molecular or lattice vibrations yielding to a precise picture of the molecular interactions in bulk materials as well as in surfaces and interfaces. Unfortunately …

Silver Nanoparticle Transport Through Soil: Illuminating The Governing Pore-Scale Processes, Ian L. Molnar

Electronic Thesis and Dissertation Repository

Engineered nanoparticles are widely used and will eventually be released to the subsurface environment and contaminate groundwater resources. However, the transport of engineered nanoparticles through soil is currently not well understood and cannot be modelled in any fundamental manner, placing groundwater resources at risk from nanoparticle contamination. This inability to accurately simulate transport is due to a lack of experimental information on nanoparticle interactions in the pore spaces of real soils.

This thesis illuminates the pore-scale processes governing silver nanoparticle transport through soil. In addition, it examines the influence of surface chemistry and grain/pore distributions on those processes. For the …

Bm3d Image Denoising Using Learning-Based Adaptive Hard Thresholding, Farhan Bashar

Electronic Thesis and Dissertation Repository

Image denoising is an important pre-processing step in most imaging applications. Block Matching and 3D Filtering (BM3D) is considered to be the current state-of-art algorithm for additive image denoising. But this algorithm uses a fixed hard thresholding scheme to attenuate noise from a 3D block. Experiments show that this fixed hard thresholding deteriorates the performance of BM3D because it does not consider the context of corresponding blocks. In this thesis, we propose a learning based adaptive hard thresholding method to solve this issue. Also, BM3D algorithm requires as an input the value of the noise level in the input image. …

Predicting Energy Demand Peak Using M5 Model Trees, Sara S. Abdelkader, Katarina Grolinger, Miriam Am Capretz

Electrical and Computer Engineering Publications

Predicting energy demand peak is a key factor for reducing energy demand and electricity bills for commercial customers. Features influencing energy demand are many and complex, such as occupant behaviours and temperature. Feature selection can decrease prediction model complexity without sacrificing performance. In this paper, features were selected based on their multiple linear regression correlation coefficients. This paper discusses the capabilities of M5 model trees in energy demand prediction for commercial buildings. M5 model trees are similar to regression trees; however they are more suitable for continuous prediction problems. The M5 model tree prediction was developed based on a selected …

Adaptive Non-Local Means Using Weight Thresholding, Asif Khan

Electronic Thesis and Dissertation Repository

Non-local means (NLM) is a popular image denoising scheme for reducing additive Gaussian noise. It uses a patch-based approach to find similar regions within a search neighborhood and estimate the denoised pixel based on the weighted average of all the pixels in the neighborhood. All the pixels are considered for averaging, irrespective of the value of their weights. This thesis proposes an improved variant of the original NLM scheme, called Weight Thresholded Non-Local Means (WTNLM), by thresholding the weights of the pixels within the search neighborhood, where the thresholded weights are used in the averaging step. The key parameters of …

Group 6 Metal Pentacarbonyl Complexes Of Air-Stable Primary, Secondary, And Tertiary Ferrocenylethylphosphines, Amir Rabiee Kenaree, Ethan R. Sauvé, Paul J. Ragogna, Joe Gilroy

Chemistry Publications

The synthesis and characterization of a series of Group 6 metal pentacarbonyl complexes of air stable primary, secondary, and tertiary phosphines containing ferrocenylethyl substituents are reported [M(CO)₅L: M = Cr, Mo, W; L = PH₂(CH₂CH₂Fc), PH(CH₂CH₂Fc)₂, P(CH₂CH₂Fc)₃]. The structure and composition of the complexes were confirmed by multinuclear NMR spectroscopy, IR and UV-Vis absorption spectroscopy, mass spectrometry, X-ray crystallography, and elemental analysis. The solid-state structural data reported revealed trends in M-C and M-P bond lengths that mirrored those of the …

Morphological, Structural And Spectral Mapping Of The Central Uplifts Of The Alga And Verlaine Craters, Mars, Bianca D'Aoust

Electronic Thesis and Dissertation Repository

Impact cratering is a ubiquitous geological process that has shaped planetary bodies of the Solar System and beyond. While the impact cratering record on Earth has been poorly preserved, the Martian surface is characterized by a very old and cratered terrain. Central uplifts within complex impact craters are of particular interest as they expose deep-seated material, some of which may correspond to samples of the early Martian crust. Central uplift formation is, however, still a poorly understood geological process. This research investigated the origin of the exposed bedrock in the central uplifts of two Martian complex craters as well as …

Solvothermal Synthesis And Characterization Of Cuins2, Cuinse2 And Agins2 Nanoparticles From Single Source Precursors, Xuzhao Zhao

Electronic Thesis and Dissertation Repository

Nanoscale semiconductors have emerged as alternative candidates for the absorber layer in solar cells. Group 11-13-16 semiconductors have received a lot attention because of their direct band gap energies, high absorption coefficients and environmental friendly nature. To date, CuInS₂, CuInSe₂ and AgInS₂ semiconductors are three of the main ternary nanomaterials investigated. Besides the application in solar cells, these nanoscale semiconductors can also be applied in areas such as biosensors and hydro catalysis.

However, it is often challenging to prepare small-sized nanoparticles with uniform size and shape, especially for large scale production. In this thesis, the synthesis …

Optical Flow At Occlusion Boundaries And In Occlusion Regions, Hua Meng

Electronic Thesis and Dissertation Repository

Optical flow is an important research area in the Computer Vision field, with the estimation of optical flow at occlusion still an open problem. Traditional approaches to this problem have either used additional terms in a regularization calculation (the flow still tends to “bleed” across occlusion boundaries) or a local least squares calculation that attempted to minimize the influence of two adjacent differently moving regions on the optical flow at points close to both regions (the flow still tends to be “corrupted” by the two regions). Ideally, optical flow for two adjacent differently moving regions should be distinct right up …

A New Technique For Interpreting Depolarization Measurements Using The Crl Atmospheric Lidar In The Canadian High Arctic, Emily M. Mccullough

Electronic Thesis and Dissertation Repository

Linear depolarization measurement capabilities were added to the CANDAC Rayleigh-Mie-Raman lidar (CRL) at Eureka, Nunavut, in the Canadian High Arctic. This upgrade enables inferences of the phases (liquid versus ice) of cold and mixed-phase clouds, including during polar winter. A rotating-polarizer module was installed in the lidar, and depolarization measurements were calibrated according to existing methods. An alternate calculation technique, using the lidar's existing visible Rayleigh elastic channel in combination with the new rotating polarizer channel, was developed. A detailed mathematical description of both methods and their calibrations is presented. The new method is superior to the traditional method for …

Recent Advances In Accumulating Priority Queues, Na Li

Electronic Thesis and Dissertation Repository

This thesis extends the theory underlying the Accumulating Priority Queue (APQ) in three directions. In the first, we present a multi-class multi-server accumulating priority queue with Poisson arrivals and heterogeneous services. The waiting time distributions for different classes have been derived. A conservation law for systems with heterogeneous servers has been studied. We also investigate an optimization problem to find the optimal level of heterogeneity in the multi-server system. Numerical investigations through simulation are carried out to validate the model.

We next focus on a queueing system with Poisson arrivals, generally distributed service times and nonlinear priority accumulation functions. We …

Surface Reconstruction From Noisy And Sparse Data, Mark A. Brophy

Electronic Thesis and Dissertation Repository

We introduce a set of algorithms for registering, filtering and measuring the similarity of unorganized 3d point clouds, usually obtained from multiple views.

We contribute a method for computing the similarity between point clouds that represent closed surfaces, specifically segmented tumors from CT scans. We obtain watertight surfaces and utilize volumetric overlap to determine similarity in a volumetric way. This similarity measure is used to quantify treatment variability based on target volume segmentation both prior to and following radiotherapy planning stages.

We also contribute an algorithm for the drift-free registration of thin, non- rigid scans, where drift is the build-up …

Energy Forecasting For Event Venues: Big Data And Prediction Accuracy, Katarina Grolinger, Alexandra L'Heureux, Miriam Am Capretz, Luke Seewald

Electrical and Computer Engineering Publications

Advances in sensor technologies and the proliferation of smart meters have resulted in an explosion of energy-related data sets. These Big Data have created opportunities for development of new energy services and a promise of better energy management and conservation. Sensor-based energy forecasting has been researched in the context of office buildings, schools, and residential buildings. This paper investigates sensor-based forecasting in the context of event-organizing venues, which present an especially difficult scenario due to large variations in consumption caused by the hosted events. Moreover, the significance of the data set size, specifically the impact of temporal granularity, on energy …

Management's Perspective On Critical Success Factors Affecting Mobile Learning In Higher Education Institutions - An Empirical Study, Muasaad Alrasheedi, Luiz Fernando Capretz, Arif Raza

Electrical and Computer Engineering Publications

Mobile learning (m-Learning) is considered to be one of the fastest growing learning platforms. The immense interest in m-Learning is attributed to the incredible rate of growth of mobile technology and its proliferation into every aspect of modern life. Despite this, m-Learning has not experienced a similar adoption rate in the education sector, chiefly higher education. Researchers have attempted to explain this anomaly by conducting several studies in the area. However, mostly the research in m-Learning is examined from the perspective of the students and educators. In this research, it is contended that there is a third important stakeholder group …

Students' Perspectives Of Mobile Learning Platforms: An Empirical Study, Muasaad Alrasheedi, Luiz Fernando Capretz, Arif Raza

Electrical and Computer Engineering Publications

Educational institutions are becoming involved in adopting technological innovations like th e mobile learning (m-Learning) platform for education. Mobile technologies are the next frontier as infrast ructure for m-Learning because they can provide high-quality learning capab ilities to satisfy the rising student demand for mobility and flexibility due to the ubiquitous nature of mobile tec hnology (smartphones) and the va st opportunities it offers, there ar e indications that smartphones could lead the next generation for learning platforms. Researchers have examin ed the idea from several angles and produced a copious amount of literature devoted to explaining the interrelationships of …

Factors Impacting Transgender Patients’ Discomfort With Their Family Physicians: A Respondent-Driven Sampling Survey, Greta R. Bauer, Xuchen Zong, Ayden I. Scheim, Rebecca Hammond, Amardeep Thind

Epidemiology and Biostatistics Publications

BACKGROUND: Representing approximately 0.5% of the population, transgender (trans) persons in Canada depend on family physicians for both general and transition-related care. However, physicians receive little to no training on this patient population, and trans patients are often profoundly uncomfortable and may avoid health care. This study examined factors associated with patient discomfort discussing trans health issues with a family physician in Ontario, Canada.

METHODS: 433 trans people age 16 and over were surveyed using respondent-driven sampling for the Trans PULSE Project; 356 had a family physician. Weighted logistic regression models were fit to produce prevalence risk ratios (PRRs) via …

Side-Chain Boron Difluoride Formazanate Polymers Via Ring-Opening Metathesis Polymerization, Samantha Novoa, Joseph A. Paquette, Stephanie M. Barbon, Ryan R. Maar, Joe Gilroy

Chemistry Publications

The synthesis, characterization, and ring-opening methathesis polymerization (ROMP) of a novel norbornene-based boron difluoride (BF₂) formazante monomer are described in detail. The polymerization studies confirmed ROMP to occur in the presence of BF₂ formazanates, and also demonstrated the controlled nature of the polymerization. The polymers retained many of the unique characteristics of the monomers in dichloromethane, including absorption and emission at maximum wavelengths of 518 and 645 nm, large Stoke's shifts (u_ST = 127 nm, 3,800 cm^-1), and the ability to act as electron reservoirs to form borataverdazyl-based poly(radical anions) (E°_{red1 …}

Galois 2-Extensions, Masoud Ataei Jaliseh

Electronic Thesis and Dissertation Repository

The inverse Galois problem is a major question in mathematics. For a given base field and a given finite group $G$, one would like to list all Galois extensions $L/F$ such that the Galois group of $L/F$ is $G$.

In this work we shall solve this problem for all fields $F$, and for group $G$ of unipotent $4 \times 4$ matrices over $\mathbb{F}_2$. We also list all $16$ $U_4 (\mathbb{F}_2)$-extensions of $\mathbb{Q}_2$. The importance of these results is that they answer the inverse Galois problem in some specific cases.

This is joint work with J\'an Min\'a\v{c} and Nguyen Duy T\^an.

Studies Of Contingent Capital Bonds, Jingya Li

Electronic Thesis and Dissertation Repository

A contingent capital bond (CCB) is a subordinated security that converts to common shares when a predetermined trigger is breached. The 2008 financial crisis and the Basel III motivate the issuance of CCBs, aiming to mitigate the too-big-to-fail problem in financial distress and to resolve financial institutions by bailing in with the firm’s own capital rather than a bailing out using the taxpayers’ money.

Within the structural modelling framework, we consider the pricing of CCBs with an affine geometric Brownian motion by assuming that coupon payments have impact on the asset value dynamics. We extend the capital structure into four …

High Pressure Studies Of Nanostructured Tio2 And Li4ti5o12 Using Raman Spectroscopy And Synchrotron X-Ray Radiation, Fengping Xiao

Electronic Thesis and Dissertation Repository

Nanomaterials have been extensively studied due to their distinctive properties such as surface effect, small-size effect and quantum size effect. In recent year, investigations of the structural and phase transformations of nanomaterials under high pressure are receiving increasing attentions. In addition to composition and synthetic routes, pressure provides a clean way to adjust interatomic distance and hence affect the crystal structure and thus properties of the nanostructured materials.Two nanomaterials (i.e. TiO₂ and Li₄Ti₅O₁₂) with different morphologies are studied in this thesis.

In part I, the high-pressure behaviours of four hydrothermal synthesized 1D rutile …

Mlaas: Machine Learning As A Service, Mauro Ribeiro, Katarina Grolinger, Miriam Am Capretz

Electrical and Computer Engineering Publications

The demand for knowledge extraction has been increasing. With the growing amount of data being generated by global data sources (e.g., social media and mobile apps) and the popularization of context-specific data (e.g., the Internet of Things), companies and researchers need to connect all these data and extract valuable information. Machine learning has been gaining much attention in data mining, leveraging the birth of new solutions. This paper proposes an architecture to create a flexible and scalable machine learning as a service. An open source solution was implemented and presented. As a case study, a forecast of electricity demand was …

A Novel Method For Assessing Co-Monotonicity: An Interplay Between Mathematics And Statistics With Applications, Danang T. Qoyyimi

Electronic Thesis and Dissertation Repository

Numerous problems in econometrics, insurance, reliability engineering, and statistics rely on the assumption that certain functions are monotonic, which may or may not be true in real life scenarios. To satisfy this requirement, from the theoretical point of view, researchers frequently model the underlying phenomena using parametric and semi-parametric families of functions, thus effectively specifying the required shapes of the functions. To tackle these problems in a non-parametric way, when the shape cannot be specified explicitly but only estimated approximately, we suggest indices for measuring the lack of monotonicity in functions. We investigate properties of these indices and offer convenient …

Identification And Survival Outcomes Of A Cohort Of Patients With Cancer Of Unknown Primary In Ontario, Canada., Chong S Kim, Malek B Hannouf, Sisira Sarma, George B Rodrigues, Peter K Rogan, Salaheddin M Mahmud, Eric Winquist, Muriel Brackstone, Gregory S Zaric

Epidemiology and Biostatistics Publications

BACKGROUND: Cancer of unknown primary origin (CUP) is defined by the presence of pathologically identified metastatic disease without clinical or radiological evidence of a primary tumour. Our objective was to identify incident cases of CUP in Ontario, Canada, and determine the influence of histology and sites of metastases on overall survival (OS).

MATERIAL AND METHODS: We used the Ontario Cancer Registry (OCR) and the Same-Day Surgery and Discharge Abstract Database (SDS/DAD) to identify patients diagnosed with CUP in Ontario between 1 January 2000, and 31 December 2005. Patient diagnostic information, including histology and survival data, was obtained from the OCR. …

The Influence Of Alloying Elements On The Crevice Corrosion Behaviour Of Ni-Cr-Mo Alloys, Nafiseh Ebrahimi

Electronic Thesis and Dissertation Repository

To enhance its corrosion resistance in aggressive media, Ni is alloyed with various amounts of Cr and Mo along with small amounts of other alloying elements such as W, Cu, and Fe. While the resulting alloys (known as Ni superalloys) show excellent passive behaviour, the function of individual alloying elements in resisting localized corrosion processes, in particular crevice corrosion is not fully understood. This study focuses on the electrochemistry and corrosion of a series of Ni-Cr-Mo (W) alloys with various Cr and Mo contents. Several electrochemical and surface characterization techniques were used to investigate the role of major alloying elements …