Theses, Dissertations, and other Required Graduate Degree Essays

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This collection contains digitized SFU theses except for those theses submitted within the last 12 months. If you cannot find the thesis you are looking for please search Recently Submitted Theses as it may be a recently submitted thesis and thus not yet available in Summit.

Investigating students' preferences and perceptions of online resources in an emergency-remote introductory programming course

Date created: 
2021-07-27
Abstract: 

Although online programming courses offer flexible learning formats, research shows that students report increased feelings of isolation and often end up dropping out of such courses. In this thesis, we investigated a study case of university students enrolled in an introductory programming course offered in an emergency-remote context. Through surveys and interviews, we sought to understand what difficulties students faced, what learning strategies they used, and what types of resources they preferred. We found that most students felt compelled to consult web-based resources (e.g., Q\&A forums, videos) on their own and chose to ignore their own notes and curated resources offered by the instructor. Although many of the students realized that they wasted time searching the web unsuccessfully, they continued to search incessantly, neither asking for help nor self-monitoring the value of their learning strategy. We discuss several possible theories and provide recommendations for improving students’ interactions with learning resources.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Parmit Chilana
Diana Cukierman
Department: 
Applied Sciences: School of Computing Science
Thesis type: 
(Thesis) M.Sc.

Preparation of nanoscale lithium niobate for non-linear optical applications

Author: 
Date created: 
2020-12-21
Abstract: 

Lithium niobate (LiNbO3) is a unique photonic material, often referred to as the “silicon of photonics”, due to its excellent optical properties. In this thesis, we advanced the development of solution-phase approaches for the preparation of LiNbO3 nanoparticles (NPs) with an average, tunable size from 7 to 100 nm. This solution-phase process results in the formation of crystalline, uniform NPs of LiNbO3 at a reaction temperature of 220 °C with an optimal reaction time as short as 30 h. Advantages of these methods include the preparation of single-crystalline LiNbO3 NPs without the need for further heat treatment or without the need for using an inert reaction atmosphere. The growth of these nanoparticles began with a controlled agglomeration of nuclei formed during a solvolysis step. The reactions subsequently underwent the processes of condensation, aggregation, and Ostwald ripening, which remained the dominant process during further growth of the nanoparticles. These processes did produce single-crystalline nanoparticles of LiNbO3, suggesting an oriented attachment process. Average dimensions of the NPs were tuned from 7 to ~100 nm by either increasing the reaction time or changing the concentration of the lithium salts used in the solvothermal process. The nanoparticles were also confirmed to be optically active for SHG. These NPs could enable further development of SHG based microscopy techniques. In this thesis, we also performed a comparative study on the role of different Li precursors during the synthesis of LiNbO3 NPs. The results of these studies suggest that the type of Li precursor selected plays an important role in nanoparticle formation, such as through controlling the uniformity, crystallinity, and aggregation of LiNbO3 NPs. The average diameter of the resulting NPs can also vary from ~30 to ~830 nm as a function of the Li reagent used in the synthesis. The selection of Li precursors also influences the phase purity of the products. Nanoparticles of LiNbO3 are explored in literature as SHG bioimaging probes for their potential to expand underdeveloped SHG based microscopy techniques. The efficient use of SHG active LiNbO3 NPs as probes does, however, require their surface functionalization with polyethylene glycol and fluorescent molecules to enhance their colloidal stability, chemical stability, and to enable a correlative imaging platform. This surface functionalization approach used functional alcohols to serve as a platform for attaching a variety of reagents, including nonreactive surface coatings (e.g., polyethylene glycol). As a demonstration of this approach to utilizing the surface chemistry derived from the silanol-alcohol condensation reaction, the surfaces of the NPs were covalently functionalized with biologically important molecules such as polyethylene glycol and a fluorescent probe. This strategy in tuning the surface chemistry of the nanoparticles based on covalent bonding to their surfaces reduced aggregation of the NPs, provided chemical stability and enabled a multimodal tracking platform for SHG nanoprobes. We also developed the first porous and monodisperse LiNbO3 NPs that were also verified to be SHG active, which could be used as contrast agents in nonlinear optical microscopy, optical limiters, biosensors, and photocatalysts. The porous nonlinear optical material can also enhance the SHG response by loading the pores with organic guest molecules (e.g., carboxylic acids, anilines). We introduce a hydrothermal method to prepare monodisperse and mesoporous LiNbO3 NPs for enhanced SHG response. This approach forms mesoporous LiNbO3 NPs with diameters of ~600 nm without additional organic additives (e.g., surfactants) to control growth and aggregation of the nanoparticles. The mesopores of the LiNbO3 NPs were loaded with organic molecules such as tartrates that offer better photochemical stability and more acentric molecular alignment to the host material. The loading of tartrate anions onto the surfaces of these nanoparticles provides enrichment of pi-electrons to LiNbO3, which enhances the SHG response of mesoporous LiNbO3 by 4 times.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Byron Gates
Department: 
Science: Department of Chemistry
Thesis type: 
(Thesis) Ph.D.

OwlCrate: A case study of subscription book boxes

Date created: 
2020-08-25
Abstract: 

Subscription boxes have been increasing in popularity over the past few years. In the publishing industry, subscription book boxes have become a new revenue stream for publishers. Currently there are over 170 subscription box companies dedicated to delivering books, some businesses ranging from a couple hundred subscribers to some having thousands. This report is a case study on one subscription book box company: OwlCrate Enterprises, a monthly subscription service delivering one new young adult book along with some other book related merchandise. This report details how OwlCrate has built a successful subscription book box service and how they have positioned themselves in the Young Adult book market.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
John Maxwell
Department: 
Communication, Art & Technology: Publishing Program
Thesis type: 
(Project) M.Pub.

Structural insights into gypsy moth pheromone-binding protein function as revealed in NMR and binding studies with pheromones and analogues

Author: 
Date created: 
2020-08-10
Abstract: 

Pheromone-binding proteins (PBPs) are small, water-soluble proteins found in the lymph of sensory hairs of male moth antennae. It has been proposed that they function as transporters of hydrophobic odorants through sensory hair lymph, but another function of these proteins is to scavenge excess pheromone molecules, to protect the odorant receptors from signal overload. In this thesis I studied two PBPs from the gypsy moth, L. dispar, from the perspectives of ligand interaction thermodynamics and kinetics, as well as the 3D structure of one gypsy moth PBP, to gain further insight into their function. Two gypsy moth PBPs have been identified, LdisPBP1 and LdisPBP2. The gypsy moth utilizes (+)-disparlure as its sole sex pheromone to attract male gypsy moths. A sympatric species, the nun moth (L. monacha) produces (-)-disparlure as a deterrent for male gypsy moths. Past studies with the LdisPBPs have shown that the two PBPs have opposite disparlure enantiomer binding preferences. Structural studies of other moth PBPs have revealed two PBP conformations, A-form and B-form. The transition between these two forms is affected by pH and presence of ligand. The mechanisms behind this pH- and ligand-induced transition is still largely unknown. In this thesis, I have studied conformational and ligand interaction dynamics of gypsy moth PBPs, with a particular focus on LdisPBP1. Thermodynamics (Kd) and kinetics properties (k’on and k’off) of LdisPBP-ligand interaction were correlated to the physiological function of PBP as either a transporter, a scavenger, or both. Equilibrium and kinetic binding assays of LdisPBPs with the natural ligands and analogues have shown cases of enantiomeric and structural discrimination. This suggests that PBPs are not passive pheromone transporters but function as initial molecular filters in the peripheral stage of pheromone perception. Correlation of Kd, k’on, and k’off with electroantennogram response patterns revealed the connection of LdisPBP-ligand interactions to odorant receptor activity through both odorant transport and scavenger functions. Structure elucidation of LdisPBP1 using NMR at pH 4.5 revealed the A-form conformation. In this conformation, LdisPBP1 has seven helices with the 7th C-terminus helix found inside the binding pocket. Subsequent pH titration and disparlure enantiomer titration monitored by NMR indicated the formation of a different conformation from that of the A-form. Findings presented in this research work provide new insights into LdisPBP binding interactions and structural implications concerning the PBP ligand binding and release mechanism.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Erika Plettner
Department: 
Science: Department of Chemistry
Thesis type: 
(Thesis) Ph.D.

PDE-based Bayesian hierarchical modeling for event spread, with application to COVID-19 infection

Author: 
Date created: 
2022-04-20
Abstract: 

Motivated partly by the ongoing COVID-19 pandemic, this project aims to develop a tool for investigating spatio-temporal spread of events. We use the records of American coronavirus disease cases over time from The New York Times to motivate and illustrate the methodological development. Wikle (2003) considers a Bayesian hierarchical model based on a diffusion-reaction equation with a space-varying diffusion rate to describe the latent spatiotemporal process underlying a collection of bird migration data. We extend the model by adding an advection term to account for the additional trend of the transmission, and considering time-varying reaction and advection terms. A Markov chain Monte Carlo (MCMC) method is applied to obtain samples from the posterior distribution of the parameters. The proposed approach is implemented via the COVID-19 data from The New York Times. The analysis results indicate that the diffusion rate is heterogeneous across USA, and the growth rate and the advection velocity are time-varying. We verify the findings from the analysis by simulation. The proposed approach appears robust to model misspecification and outperforms other approaches in the simulation settings.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
X. Joan Hu
Department: 
Science: Department of Statistics and Actuarial Science
Thesis type: 
(Project) M.Sc.

The alerting effect occurs in simple – but not compound – visual search

Author: 
Date created: 
2022-05-05
Abstract: 

Alerting (e.g., a brief flash preceding a target display) facilitates simple visual tasks that involve one step: locate a pop-out item within an array. It is unknown whether alerting facilitates compound tasks involving two steps: locate the pop-out item, then identify a detail of that item. I show that alerting facilitates each compound task component when tested separately, but not when combined. Yet, alerting facilitates compound tasks when the item reappears in the same location on successive trials. Such repetition may permit attention to linger at that location, allowing the first component to be bypassed. In practice, this turns the compound task into a simple task. That hypothesis was confirmed by using a re-orienting cue to shift attention to another location. An account of the absence of alerting in compound tasks is proposed in terms of the temporal relationship between an enhancement period and the sequence of visual processing stages.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Thomas Spalek
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

‘The hunt is always sweeter than the kill’: Re-thinking desire through a ‘Proustian’ lens

Author: 
Date created: 
2022-03-25
Abstract: 

The ‘problem’ of desire has permeated philosophical thought all throughout history and across cultures, with desire persistently interpreted in Western Tradition as a potential danger, both to individuals and societies as a whole—mainly due to its close association with passion and emotions and its perceived distance from reason. The real ‘danger’ with regards to human desire, is simply that we continue to face and perpetuate massive misunderstandings about it. This includes ongoing misperceptions around what desire truly is and means, as well as why it emerges and how it operates within us. We’re also lacking a relatable paradigm of desire in Western thought, that accurately explains its complex relationships with both pain and pleasure. One of the most insightful explorations on the essence and workings of desire, can be found though a close reading of Marcel Proust’s modernist fictional novel In Search of Lost Time. And when combined alongside the philosophical theory of desire formulated by Gilles Deleuze, in addition to discussions on metaphysical desire and longing for the ‘Other’ argued by Emmanuel Lévinas, possibilities for a new and collaborative theory on desire emerge. A theory that can provide us with much needed understandings on how human desire actually forms and behaves, as well as our active and productive role in it. A collective philosophical theory based on these three distinct writers rejects dominant understandings which describe desire as an inherently painful ‘lack’, perpetually in search of pleasurable ‘satisfaction’ through the pursuit and ‘acquisition’ of real ‘objects’. Desire is more accurately understood through its painfully pleasurable trajectory and as the productive activity of forming associations between various ‘objects’, either real or imagined, resulting in complex assemblages of desire. These multi-element aggregates are fuelled through the constructed connections and continued fantasies or belief in them, as well as by the ongoing distance between a desiring subject, primary ‘object’ and all the contextual elements involved. The combined work of these authors offers a more accurate and relatable explanation of the source and essential characteristics of desire, as well as the complexities of the entire desiring process.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Stephen Duguid
Department: 
Arts & Social Sciences: Liberal Studies Program
Thesis type: 
(Project) M.A.L.S.

Evolution of an isthmus in a region of minimal relative sea level change, Calvert Island, BC central coast

Author: 
Date created: 
2022-04-04
Abstract: 

The northwest coast of Calvert Island, British Columbia, hosts a large isthmus that connects two rocky headlands. Previous research suggested that its surface stabilized within the last ~500 years, but the true timing of stabilization and the origin of the isthmus were still unknown. This study used remote sensing, ground-penetrating radar (GPR), and optical dating to resolve isthmus geomorphology, stratigraphy, and structure, and to provide limiting ages, respectively, with the goal of understanding the evolution and timing of stabilization of the landform. The subsurface sedimentary architecture revealed by the GPR data, supported by a digital surface model (DSM), suggest that the isthmus began forming in the east and subsequently prograded west. The sample ages suggest that the prograding beachfaces stabilized near the surface ~600 – 700 years ago in the east, while dunes in the west stabilized ~150 years ago, however, the bulk of the isthmus is likely older.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Tracy Brennand
Department: 
Environment: Department of Geography
Thesis type: 
(Thesis) M.Sc.

Measuring economic prosperity in Indigenous communities: The Metlakatla Cumulative Effects Management Program

Author: 
Date created: 
2022-04-14
Abstract: 

The purpose of this report is to assist Metlakatla First Nation (MFN) in making decisions on selecting indicators for monitoring high-priority values in the economic prosperity pillar of the Metlakatla Cumulative Effects Management (CEM) Program. The research objectives are to identify the priorities in economic prosperity for MFN and indicators that are most relevant and feasible for measuring these priorities. The recommended indicators are derived from a review of 12 relevant economic prosperity frameworks, input from Metlakatla focus groups, and analysis of data collected from the 2020 Metlakatla Membership Census. Recommendations also include management strategies to improve economic prosperity outcomes and the next steps to incorporate recommended indicators to the CEM Program.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Thomas Gunton
Department: 
Environment: School of Resource and Environmental Management
Thesis type: 
(Project) M.R.M. (Planning)

Data mining and machine learning for identification of risk factors and prediction of cognitive changes among aging populations

Author: 
Date created: 
2022-04-14
Abstract: 

Cognitive decline is a common consequence of aging, with dementia at the extreme end of this process. The decline in cognition may decrease the ability and efficiency of performing daily living activities among older adults. Unfortunately, existing pharmacological treatments are not effective at delaying the incidence of dementia and cognitive impairment. As such, many medical recommendations are focused on preventative measures (i.e., lifestyle activities, social engagement, physical activity, and proper diet) to maintain cognitive health. Although the results of the previous studies in this area are promising, there are yet unanswered questions that restrict the practical applications and recommendations of the interventions and their impact on cognition. This thesis research investigates the application of data mining methods to answer some of the yet unanswered questions. Accordingly, this thesis first aims to investigate the impact of engagement in different intensities and frequencies of physical activity on two domains of cognitive function. We seek to test the hypothesis that engaging in a physically active lifestyle leads to relatively preserved cognitive health during aging. The findings of the study assist communities to promote healthy cognitive aging among older populations by implementing new policies and providing recommendations about the details of engaging in optimal physical activity in terms of intensity and frequency. Second, we aim to focus on the impact of cognitive reserve on cross-sectional cognitive function, short-term and long-term rates of cognitive changes over 2 years and 10 years of follow-up. Our objective is to attempt to improve the limitations of previous studies in terms of study design, intervention characteristics, and methodological issues. Our use of data mining approaches and appropriate study design models assist in controlling the impact of confounding factors and moving forward towards investigating the causal relationship rather than correlational association. The results of this study contribute to establishing interventions to be developed during the aging process to delay cognitive decline. Lastly, we aim to investigate the possibility of implementing a model to predict future cognitive changes with the combination of categorical and continuous data from multiple domains such as sociodemographic, health, psychology, and cognition, simultaneously. We also use a machine learning-based framework to identify the most important predictors of future cognitive changes. Incorporation of the findings of the study in public health policies assists in improving the counseling of older adults and caregivers and developing the plan of cognitive care and effective interventions to develop healthy aging.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Steve DiPaola
Department: 
Communication, Art & Technology: School of Interactive Arts and Technology
Thesis type: 
(Thesis) Ph.D.