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.

Navigating Coexistence: Ecological Drivers and Social Implications of Predator-induced Regime Shifts in the Northeast Pacific

Author: 
Peer reviewed: 
No, item is not peer reviewed.
Date created: 
2019-06-05
Abstract: 

Societies are greatly challenged by regime shifts, when ecosystems undergo fundamental changes that are rapid, unexpected, and difficult to reverse. In order to better navigate these transitions, we need information on the drivers, species interactions, and feedbacks that influence ecosystem dynamics, and an understanding of how human communities are adapting to the profound shifts in ecosystem resources. My thesis applies this social-ecological system lens to an iconic regime shift – the recovery of sea otters (Enhydra lutris) in the Northeast Pacific that is triggering a trophic cascade which causes sea urchin and shellfish-dominated rocky reefs to become productive macroalgae-dominated forests. To examine how predation and herbivory interactions affect the structure, function, and resilience of reef communities on the central coast of British Columbia (BC), I conducted four years of subtidal surveys and experiments. These data confirm the critical role of sea otter predation in suppressing urchin populations, but also demonstrate for the first time, that complementary predation by mesopredators (i.e. sunflower sea star Pycnopodia helianthoides) further enhance the resilience of kelp forests by consuming smaller-sized urchins that are otherwise unconsumed by otters. I also experimentally quantified how numerical and behavioural factors collectively influence herbivory rates that maintain alternative reef states. Kelp consumption rates showed a positive but non-linear relationship with urchin biomass, whereas food subsidies and predator-avoidance behaviour reduced urchin grazing rates. Next, to understand how sea otter recovery influences coastal Indigenous communities, I worked in a collaborative Indigenous partnership to host workshops and conduct survey interviews in a comparative case study. We identified 22 social-ecological conditions that can influence Indigenous peoples’ ability to adapt to otters, and revealed how perceptions and adaptive capacity differed between a BC First Nations community and an Alaska Sugpiaq Tribe. These quantitative and qualitative data suggest that coexistence with sea otters could be improved through strengthening Indigenous agency and authority and enabling collaborative adaptive otter management grounded in traditional knowledge and western science. As a whole, this thesis highlights the complexities, surprises, and contextual nuances that characterize sea otter recovery in tightly coupled social-ecological systems, and provides the foundations for a road map to improve future human-otter coexistence.

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

The present status of the curation crisis and deaccessioning in the United States

Author: 
Date created: 
2019-01-21
Abstract: 

Archaeological collections in the United States were deemed to be in crisis in the 1970s. Federal curation guidelines were issued in 1990 with 36 CFR Part 79, followed by a call for national standards by the Society for American Archaeology. It is not clear if these were successful because the current status of collections is generally unknown. Given this, I surveyed curation practices at 11 major US archaeological repositories, impediments to their implementation of modern curation standards, and their deaccessioning policies. Although many of the individual standards were being met, around one-third of the collections do not meet all the standards. Methods used to meet standards varied across institutions, and the major contributor to collections was heritage resource management. Funding and space were the most often reported impediments. Every institution reported deaccessioning, but not all had policies. Ultimately, collections have improved since the 1970s, but further progress is needed.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Mark Collard
Department: 
Environment: Department of Archaeology
Thesis type: 
(Thesis) M.A.

Creating space for authentic voice in Canada's screen industry: A case study of 'Women In the Director's Chair (WIDC)'

Author: 
Date created: 
2019-01-25
Abstract: 

Using an appreciative inquiry approach and sharing a reflexive 4-D (i.e., discovery, dreams, design, delivery / destiny) narrative that explores societal, organizational and personal perspectives, this action research study describes a specially designed, internationally respected Canadian national professional development initiative for women screen directors, entitled ‘Women In the Director’s Chair (WIDC)’. The narrative traces how this initiative came to be, and within the context of North America’s ‘waves’ of feminism, where it is placed on the landscape of Canada’s screen industry. While foregrounding a well-documented socio-cultural ‘lack of confidence’ in women leaders and in particular in women screen directors in Canada, the study contextualizes the personal ‘leadership experience’ narratives of WIDC director participants while the author makes meaning of her own leadership journey as a co-creator of the WIDC initiative. The author further explores the twenty-two-year evolution of WIDC’s transformation-oriented pedagogical design as she reflects on the positive core of WIDC and asks, ‘What is WIDC? What was learned and what’s next?’ Sharing leadership metaphors that offer guidance for navigating a ‘continuum of confidence’ and offering a theoretical map towards transformation for individual women as well as feminist or like-minded organizations, the study concludes with a call to action to adopt an appreciative growth-minded stance in order to create space for authentic voices to thrive in Canada’s screen industry, in particular the voices of female leaders.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Carolyn Mamchur
Department: 
Education: Faculty of Education
Thesis type: 
(Thesis) Ed.D.

How to slash GHG emissions in the freight sector? Policy insights from a technology adoption model of Canada

Author: 
Date created: 
2019-01-09
Abstract: 

The movement of goods through freight transportation accounts for approximately 6% of total Greenhouse Gas (GHG) emissions worldwide and 10% of Canada’s emissions, yet the freight sector is rarely targeted by GHG abatement research and policy. To address this gap, I use a technology adoption model (CIMS-Freight) to explore the effectiveness of policies in achieving GHG reductions in land freight (trucking and rail), and to determine scenarios that achieve Canada’s ambitious GHG reduction targets (i.e. 80% by 2050 relative to 2005 levels). To account for uncertainty in model parameters, I incorporate a Monte Carlo Analysis in which I run 1000 iterations of each simulation. My modeling results indicate that current policies (i.e. fuel efficiency standards as well as the federally proposed carbon price and low-carbon fuel standard) will not achieve 2030 and 2050 GHG reduction targets – where freight emissions will continue to rise, albeit at a lower rate than a “no policy” scenario. I also simulate the effectiveness of several individual policies: fuel efficiency standards, a carbon tax, low-carbon fuel standard (LCFS), a zero-emissions vehicle (ZEV) mandate for truck and purchase subsidy. Even at their most stringent levels, no individual policy has a high probability (at least 67% of Monte Carlo iterations) of achieving 2030 or 2050 GHG reduction targets. Finally, I find that several policy combinations can have a high probability of achieving 2050 goals, in particular a stringent ZEV mandate for trucks complemented by a stringent LCFS. While other effective policies and policy combinations are possible, it is clear that Canada’s present and proposed policies are not nearly stringent enough to reach its ambitious emissions reductions targets.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Jonn Axsen
Department: 
Environment: School of Resource and Environmental Management
Thesis type: 
(Project) M.R.M.

Designing eBooks to facilitate mathematical dialogue during shared reading

Author: 
Date created: 
2019-01-15
Abstract: 

This research aimed to investigate the impact of variation in eBook design, specifically hotspots, on caregiver-preschooler dyads’ communications about mathematics story content during shared reading. Two eBooks were designed and compared. Hotspots in the math eBook guided joint attention to mathematically-related activated features; hotspots in the emotion-action eBook guided joint attention to emotions and actions of the characters. The hotspots were matched in number and type across both eBooks. The narrative and illustrations remained consistent between the two eBooks. The dyads’ interaction with different types of hotspots; and their use of spoken utterances and gestures were compared across the two conditions. Thirty-two dyads participated in this study; 16 in each group. Findings showed that, in both groups, all caregivers and children used spoken utterances and gestures, albeit to different extent, to express the mathematics content in the narrative. However, spoken utterances and gestures that aligned with mathematics occurred more frequently among dyads in the math condition compared to the other condition. Further, caregivers in the math condition responded to hotspots by asking high-level cognitive questions, and both caregivers and children in this condition reacted mostly by repeating what was heard. In the emotion-action condition, dyads reacted emotively to the hotspots. Findings also showed that dyads in the math condition – as opposed to their peers - tended to discuss the embedded mathematics activities. Thematic analysis was done to explore in more depth the interplay between the acting on the hotspot and the narrative concerning the communication about mathematics as the dyads discussed two activities embedded in the story. Three themes emerged regarding scaffolding of mathematical ideas, co-construction of ideas, as well as seeking self-discovery and agency of the child. Findings from the Caregiver Satisfaction Questionnaire showed differences across conditions in regards to the children’s attention; and similarities in perceptions of the children’s enjoyment and willingness to share eBooks in the future. Findings from this research raise implications for the future designs of eBooks; particularly regarding the content and placement of the hotspots.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Phil Winne
Department: 
Education: Faculty of Education
Thesis type: 
(Thesis) Ph.D.

Developing a vector light sensor

Author: 
Date created: 
2019-01-10
Abstract: 

Over the past few decades, numerous sensors have been invented for the measurement of light intensity. In most cases, a setup external to the sensor is required to detect the direction of an incoming beam of light. In this work, the design, fabrication, and characterization of a novel light sensor is described. The three-dimensional structure of the sensor allows it to detect both the intensity as well as the direction of the incident light beam, hence becoming a vector light sensor (VLS). The sensor structure is based on creating photodiodes on sidewalls of miniaturized raised or inverted pyramids etched in silicon. Each photodiode was formed by selective doping of the material on each facet of the pyramid, forming a photodiode with the P-type substrate. A set of signal processing algorithms was developed to estimate the direction and the distance of a light source from the sensors. The light sensing devices with both raised and inverted pyramid structures were then fabricated in a cleanroom based on silicon microfabrication technologies. Throughout the process, the lithography step for the textured surface needed to be optimized. An interface circuit was designed and used to amplify and process the signals from the devices. The device operation was verified experimentally to estimate the direction of a light beam. The small size and low power consumption of the individual sensors make them suitable for applications were simple distance and direction estimation is required. The sensors can be arrayed to provide light-field information in the plane of sensor.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Behraad Bahreyni
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) M.A.Sc.

Decision feedback scheme for spatial modulation

Author: 
Date created: 
2019-01-25
Abstract: 

Spatial Modulation (SM) is a newly developed Multiple Input Multiple Output (MIMO) technique where the antenna/spatial constellation is used as an information carrying unit in addition to the modulation constellation. Traditional SM techniques rely on periodic insertion of the pilot symbols to estimate the channel state information; however, it reduces the effective throughput. A differential SM (DSM) technique was developed to circumvent the need of channel estimation altogether. However, the computational complexity of the DSM increases exponentially with the increase of antennas and becomes impractical even for a moderate antenna array. In this scenario a novel clustering based decision feedback (CB-DFB) scheme is proposed in this thesis which similar to DSM does not require any pilot symbols, and yet has a very low complexity. A generalized CB-DFB scheme is later proposed which further overcomes the constraints of traditional SM techniques and increases the overall throughput.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Paul Ho
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) M.A.Sc.

Human lung cell responses caused by roadside particle types

Author: 
Date created: 
2019-01-22
Abstract: 

Particulate matter (PM), especially traffic-derived particles, is associated with adverse effects on human health. An in vitro dose-response methodology using human lung cells A549 was adopted to investigate lung cell culture responses [cytokine expression Interleukin (IL) –6, IL-8, and cell death] following incubation with traffic-derived particles. The basis of this study was to investigate interactions between the known components on ambient particles proximal to roadways. In using ambient particle type ERM-CZ120, and laboratory mimics of PM, cellular responses clearly indicate the importance of insoluble particle types that are internalized via endocytosis. Particle size appears to not be a principal factor, but particle-air interface chemistries, while not investigated in this work, are likely important. The soluble species used herein did not effect a response when introduced alone, but when combined with insoluble particle types, the cellular response in excess of the insoluble particle alone was measured. A probable mechanism is that the insoluble particles function as carriers, via endocytosis, and that process provides an access route for internalization of soluble species. As evidenced by one set of experiments, prediction of overall cellular response to a given dose of a specific particle type is not trivial. Ferrous iron, when introduced with silica particles, effected significant down-regulation of expressed cytokines, whereas lead ions effected significant up-regulation, but when ferrous iron and lead ions were co-administered with silica particles, cytokine expression was down-regulated. These results indicate the necessity to measure specific cellular responses as an outcome following a dose with a specific particle composition of insoluble and soluble components for which detailed physical and chemical composition information is known, and not to extrapolate to other particle types.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Dr. George R. Agnes
Department: 
Science: Department of Chemistry
Thesis type: 
(Thesis) Ph.D.

Exploring the link between the Conceptual Model of Avalanche Hazard and the North American Public Avalanche Danger Scale

Author: 
Date created: 
2019-01-11
Abstract: 

In 2010, Statham, Haegeli, et al. (2018) introduced the Conceptual Model of Avalanche Hazard (CMAH) to improve transparency and consistency of avalanche bulletin production in North America. However, since the CMAH has no explicit link to the avalanche danger scale, forecasters must rely on their own judgment to assign danger ratings, which can lead to inconsistencies in public avalanche risk communication. My research aims to address this missing link by exploring the relationship between avalanche hazard assessments and danger rating assignments in public avalanche bulletins. Using conditional inference trees, key decision rules and components of the CMAH influencing danger rating assignments are extracted. While the analysis offers insights into the assignment rules, it also highlights substantial variability that cannot be explained by components of the CMAH. The results from this study offer a foundation for critically reviewing existing forecasting practices and developing evidence-based decision aids to increase danger rating consistency.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Pascal Haegeli
Department: 
Environment: School of Resource and Environmental Management
Thesis type: 
(Project) M.R.M.

Refining the chronostratigraphy of the Lower Nanaimo Group, Vancouver Island, Canada, using detrital zircon geochronology

Author: 
Date created: 
2018-12-17
Abstract: 

Convergent-margin basins (CMBs) are rich in broadly coeval detrital zircon (DZ) owing to the proximity of active magmatic belts. Consequently, DZ geochronology can be employed to assess the utility of stratigraphic frameworks developed for these basins. This study uses DZ data to assess the utility of lithostratigraphy developed for the Cretaceous-aged lower Nanaimo Group in the Georgia Basin, Canada. Results show that the basal lithostratigraphic unit of the Nanaimo Group, the Comox Formation, comprises strata that are neither time correlative nor genetically related. The three lithostratigraphic units directly overlying the Comox Formation (Haslam, Extension, and Protection formations) comprise strata with similar genetic affinities, indicating that deposition of these units was not entirely sequential, and contemporaneous in some locales. Further, sediment provenance evolved through time, which the existing lithostratigraphic framework does not reflect. This work demonstrates that DZ geochronology can effectively test the utility of stratigraphic frameworks in CMBs.

Document type: 
Thesis
Senior supervisor: 
Shahin E. Dashtgard
Department: 
Science: Department of Earth Sciences
Thesis type: 
(Thesis) M.Sc.