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.

Expanders in power law graphs

Date created: 
2018-10-22
Abstract: 

Random power-law graphs on n vertices can be defined in different ways. One model we study describes graphs where the expected number of vertices of degree x is proportional to a power law 1/x^β, for constant β>0. In another model, the exact degree sequence follows the power-law distribution and each vertex i has degree pn/i^β, for 0

Document type: 
Thesis
File(s): 
Senior supervisor: 
Valentine Kabanets
Department: 
Applied Sciences: School of Computing Science
Thesis type: 
(Thesis) M.Sc.

Sub-lethal effects of clothianidin on early life stage sockeye salmon (Oncorhynchus nerka)

Author: 
Date created: 
2018-11-19
Abstract: 

One of the contaminants possibly contributing to declining sockeye salmon (Oncorhynchus nerka) in the Fraser River is pesticides. In this 4-month study, the effects of environmentally relevant concentrations of waterborne clothianidin (0.15, 1.5, 15 and 150 μg/L) on embryonic, alevin and early swim-up fry sockeye salmon derived from four unique genetic crosses of the Pitt River, BC stock were investigated. There were no significant effects of clothianidin on survival, hatching, growth or deformities, although genetic variation significantly affected these endpoints. Clothianidin caused a significant 4.7-fold increase in whole body 17β-estradiol levels in swim-up fry after exposure to 0.15 µg/L, but no effects were observed on testosterone levels. These results indicate additional examination of clothianidin and its effects on salmonid gonad development and the reproductive endocrine axis in general, is warranted.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Vicki Marlatt
Department: 
Science: Biological Sciences Department
Thesis type: 
(Project) M.E.T.

Probing the climate target and climate policy implications of abundant natural gas in North America

Author: 
Date created: 
2018-11-02
Abstract: 

The past decade witnessed breakthroughs in the extraction of shale and other unconventional natural gas sources, substantially increasing the estimated low-cost supply of natural gas in North America, particularly in the United States. This thesis is an empirical investigation of whether, and to what extent, a falling cost of plentiful natural gas is a benefit or a problem for fighting climate change by exploring the implications of abundant gas on various aspects of climate policy. On the one hand, natural gas is less-emissions intensive than coal and conventional crude oil, and so substitution to natural gas from these sources can potentially serve as a mitigation tool. On the other hand, lower cost gas is only a partial de-carbonization measure relative to near-zero Greenhouse Gas (GHG) technologies like nuclear, carbon capture and storage, and renewable energy. I examined these and other considerations regarding natural gas’ interplay with climate policy using the CIMS hybrid energy-economy model. Some key focus areas included: What are the near-term implications of abundant gas on GHG emissions? What are the implications over a longer period of transition, such as to 2050? How might abundant gas play a key role in specific sectors? What impact might abundant gas have on a staged implementation of policy, with differing levels of policy stringency by sector? Some key findings concerning the gas revolution’s interplay with climate policy are that: Abundant natural gas results in only slight reductions in near-term emissions relative to scarce gas scenarios, although near-term reductions for the power sector are significant. Abundant natural gas makes it harder to achieve deep de-carbonization by 2050 relative to scenarios with scarce gas. Abundant natural gas worsens emissions leakage from the power sector to end use sectors when the former is subject to stringent policy while the latter is not. Abundant natural gas may make it easier to achieve emissions reductions in sectors such as heavy trucking, provided it is coupled with certain complementary fuels like renewable natural gas and climate policy. Otherwise it could result in higher emissions; and Abundant natural gas, combined with unanticipated policy, can achieve deep de-carbonization by 2050. However, realizing this outcome necessitates higher carbon prices as the unanticipated policy creates additional costs when coupled with abundant natural gas.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Mark Jaccard
Department: 
Environment: School of Resource and Environmental Management
Thesis type: 
(Thesis) Ph.D.

An institutional ethnography of substance-use practices among nurses and related management intervention practices in a province in Western Canada

Author: 
Date created: 
2018-12-05
Abstract: 

When nurses have problems with substance use and are reluctant to seek treatment, their health and wellness are put at risk and their care provision to the public is potentially compromised. Nurses’ substance-use problems and their management through professional organizations’ treatment programs are underresearched and poorly understood overall, and particularly from a Canadian perspective. The disjuncture I experienced between my own embodied experiential knowledge as a nurse and the conceptually based, decontextualized, individuated “official accounts” of the issue I found in the professional and scholarly literature became the problematic that I explored in a multiphase, manuscript-based doctoral study. I carried out a critical integrative review of the literature on nurses’ substance-use problems, followed by an institutional ethnographic inquiry, in which I aimed to discover (a) how dominant discourses in nurses’ talk about their everyday worlds organized their substance-use practices and (b) how nurses’ experiences were managed in a regulatory treatment program. I utilized data from interviews with 12 standpoint informants (nurses in a regulatory program for substance-use problems) and six secondary informants from different standpoints in the institution, as well as analyses of relevant institutional texts. This work yielded significant original findings. Dominant individuated, moralistic, decontextualized discourses in nurses’ talk about their everyday worlds and in professional and scholarly texts silenced nurses’ experiences of work stress. Employers’ roles in nurses’ working conditions were obscured. Nurses’ substance-use practices, particularly alcohol, were organized in ways that enabled them to silently manage their distress and keep working. Nurses gaining capacities to self-advocate for improved working conditions was linked to their recovery from substance-use problems. The standardized regulatory treatment program studied was not based on current norms of practice; did not afford nurses the right to choose treatments; privileged physicians while silencing and subordinating nurses; and was rife with conflicts of interest, power imbalances, and private corporate benefits—all acritically accepted by the regulatory body. The important new nursing knowledge gained informs prevention, treatment, regulatory, and education processes aimed to address nurses’ substance-use problems. It does so from nurses’ everyday knowledge and standpoint, furthering their interests and those of other disciplines concerned with professional power and domination.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Nicole S. Berry
Department: 
Health Sciences: Faculty of Health Sciences
Thesis type: 
(Thesis) Ph.D.

O Dio Che Bella: A novella project

Author: 
Date created: 
2018-11-20
Abstract: 

The question—what happens to emotionally repressed, distracted, detached, freedom-loving Anglo-North American visitors who come to Italy and actually encounter the alleged freedom that Italy offers?—is examined by means of research-creation—fiction writing: in the form of a novella, a synthesis of major GLS themes—combining artistic expression and scholarly investigation using a bricolage method of constructing objects from everyday materials by quoting from and alluding to texts: including the Prometheus Myth, Freud, and Mudford, and seventy others from GLS course syllabi. Part one shows the disorienting influence of Italian culture on the tourist; part two shows the effect of this on the visitor’s memory—seeking refuge in the everyday in thought and action can’t prevent the assault of the past on the present, and by the end the visitor’s interior world is radically changed. Theoretical influences on the novella are discussed in the preceding Statement of Intent.

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

Gas diffusion in thin porous catalyst layers of PEM fuel cells

Author: 
Date created: 
2018-10-30
Abstract: 

Oxygen molecules reach the reaction sites in the cathode catalyst layer (CL) of PEM fuel cells through diffusion, and the water vapor produced at the cathode leaves the reaction sites through diffusion. Therefore, the gas diffusivity of CL influences fuel cell performance. Uniform oxygen delivery to the Pt particles is one of the primary parameters ensuring high activity level of Pt particles and prolonging the CL lifetime. A sufficient supply of oxygen to the CL is required to achieve high current densities. Therefore, to reach high power outputs with low Pt loading, it is vital to understand the mechanism and improve the oxygen diffusion rate within CL and investigate the effects of different operating conditions on its performance. To investigate the effect of different CL designs and operating conditions on gas diffusivity, a modified Loschmidt cell was used to measure the gas diffusivity of CL. Also, the pore size distribution of CL was measured with N2 adsorption porosimetry. Moreover, the structure of CL was modeled through considering a packed-sphere model for carbon particles within agglomerates, and a network of overlapped spherical agglomerates forming the CL. The gas diffusion problem was solved analytically for the CL structure considering both Knudsen and molecular mechanisms. The results show that decreasing the ionomer content of CL from an ionomer to carbon weight ratio of 1.5 to 0.5 increases the relative diffusivity by 400%. Dry milling the catalyst powders for 48 hours led to 50% drop in the relative diffusivities of CL. Drying the catalyst ink on the support substrate at elevated temperatures improved gas diffusivity in some cases. The CL effective diffusivity is higher in higher operating temperature; however, its relative gas diffusivity is lower. High compressive loads (30 MPa or 50 MPa) reduces the CL diffusivity; however, in range of fuel cell operating condition (<5 MPa) the effect is negligible. The effect of gas relative humidity on the relative diffusivity of CL is negligible. On the other hand, liquid water reduces CL relative diffusivity. For example, a 25 wt. % water content in CL results in a 25% drop in relative diffusivity.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Majid Bahrami
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) Ph.D.

Quantitative measurements of biological/chemical concentrations using smartphone cameras

Author: 
Date created: 
2018-11-16
Abstract: 

This thesis presents a smartphone-based imaging system capable of quantifying the concentration of an assortment of biological/chemical assay samples. The main goal of this thesis work is to construct an image database which characterizes the relationship between color information and concentrations of the biological/chemical assay sample. For this aim, a designated optical setup combined with image processing and data analyzing techniques was implemented. A series of experiments conducted on selected assays, including fluorescein, RNA Mango, homogenized milk and yeast have demonstrated that our proposed system estimates the concentration of fluorescent materials and colloidal mixtures comparable to currently used commercial and laboratory instruments. Furthermore, by utilizing the camera and computational power of smartphones, eventual development can be directed toward extremely compact, inexpensive and portable analysis and diagnostic systems which will allow experiments and tests to be conducted in remote or impoverished areas.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Ash Parameswaran
Pablo Nepomnaschy
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) Ph.D.

Change detection and Chinese characters: The reader advantage

Author: 
Date created: 
2018-10-22
Abstract: 

The change-detection task can be used to assess how efficiently individuals perceive visual information. While reading ability allows us to efficiently recognize written characters, little is known about whether it also facilitates detection of changes to these characters. Three experiments were conducted to investigate this question. Participants saw many Chinese characters or Chinese-like artificial characters in flickering images and were required to find the one that was changing. Chinese readers were faster than non-readers when detecting changes to Chinese characters, but there was no difference between the performance of readers and non-readers when detecting changes to meaningless artificial characters. Also, readers detected changes faster when all of the unchanging characters were Chinese, and slower when they were artificial. These findings demonstrate a reader advantage when detecting changes to Chinese characters. That is, readers' ability to differentiate meaningful and meaningless written characters allowed them to detect character changes more efficiently.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Richard Wright
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

In pursuit of the quarry: Exploring lithic exchange on the Interior Plateau of British Columbia

Author: 
Date created: 
2018-10-26
Abstract: 

This thesis represents an exploratory provenance study to map the spatial distribution of lithics from the Arrowstone Hills lithic source, located near Cache Creek BC, across the Southern Interior Plateau. Using X-Ray Fluorescence analysis, an elemental signature for this source was generated, against which lithic artifacts from archaeological sites located across the Plateau were compared. The Arrowstone Hills source was also compared to five other lithic sources on the Plateau and Northwest Coast. It was determined that the Arrowstone Hills source is part of a geological complex that includes at least three other nearby lithic sources possessing a similar elemental signature, named here the Kamloops Fine-Grained Volcanic complex. Furthermore, it was determined that lithics from this complex are ubiquitous across the Plateau, and were likely moved through exchange networks. Cultural factors such as kin relationships, resource rights, and territorial sovereignty likely influenced how these networks operated at different times throughout the past.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Rudy Reimer
George Nicholas
Department: 
Environment: Department of Archaeology
Thesis type: 
(Thesis) M.A.

Identifying contemplative intensity in cognitive architectures for virtual-agent minds

Author: 
Date created: 
2018-11-29
Abstract: 

This interdisciplinary dissertation identifies contemplative intensity in cognitive architectures for virtual-agent minds. This research semantically interprets contemplative intensity through rubrics derived from Kantian Aesthetic Philosophy and Crawfordian Interaction Design. This dissertation adopted mentalist rather than behaviorist epistemological approaches towards exploring the artificial psyche and the interactive capabilities of a virtual-agent’s mind (from mechanistic finite-state machines to “deep thinkers”). A qualitative methodology was selected to triangulate hermeneutic exegesis alongside an expert interview validation process. These methods scrutinized the: state-of-the-art; architectural cognitive components, interconnections; and their relationship to five speculative virtual-agent contemplation scenarios. This hermeneutic exegesis was conducted with graph-based flow-chart representations of these scenarios. These graphs were created with the PyPhi calculator which normally deals with quantitative measurements of consciousness (i.e. Integrated Information Theory, aka. IIT) rather than the qualitative assessment of contemplative intensity. These flow-chart examples represent the component configurations of three established cognitive architectures: ACT-R, SOAR, and CLARION. The purpose of this study was to determine whether contemplative intensity could be detectable through IIT-graph visualization at an architectural level in a virtual-mind and which cognitive architecture (and/or architectural components) was most likely to intensify contemplation for this mind in a virtual world. These flow-chart illustrations representing architecturally enhanced minds helped categorize virtual-agents according to their overall cognitive capabilities and provided discussion inspiration for the experts during the interviewing process. A combination of solo hermeneutic exegesis and expert opinions determined that the IIT lens could not sufficiently qualify contemplative intensity for virtual-agent minds at an architectural resolution level of flow-chart analysis. On a positive note, the experts confirmed the validity of the mentalist epistemological perspective as well as the initial assumption that CLARION was the best architecture to intensify contemplation. However, these experts attributed their CLARION preference to architecturally-agnostic metacognitive properties rather than to CLARION’s idiosyncratic architectural configuration. These experts also insisted on the value of extra-architectural mechanisms and algorithms as well as the semantics from the virtual environment. These additional findings further confirm the qualitative limitations of the IIT lens for architecturally identifying contemplative intensity in virtual-agent minds. This dissertation concluded with proposed heuristics and suggestions for future research.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Stephen DiPaola
James Bizzocchi
Department: 
Communication, Art & Technology: School of Interactive Arts and Technology
Thesis type: 
(Thesis) Ph.D.