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.

Color Constancy for RGB and Multispectral Images

Author: 
Date created: 
2017-04-03
Abstract: 

The problem of inferring the light color for a scene is called Illuminant Estimation. This step forms the first task in many workflows in the larger task of discounting the effect of the color of the illuminant, which is called Color Constancy. Illuminant Estimation is typically used as a pre-processing step in many computer vision tasks. In this thesis, we tackle this problem for both RGB and multispectral images. First, for RGB images we extend a moments based method in several ways: firstly by replacing the standard expectation value, the mean, considering moments that are based on a Minkowski p-norm; and then secondly by going over to a float value for the parameter p and carrying out a nonlinear optimization on this parameter; and finally by considering a different expectation value, generated by using the geometric mean. We show that these strategies can drive down the median and maximum error of illuminant estimates. And then for multispectral images, we formulate a multiple-illuminants estimation problem as a Conditional Random Field (CRF) optimization task over local estimations. We then improve local illuminant estimation by incorporating spatial information in each local patch.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Mark S. Drew
Ze-Nian Li
Department: 
Applied Sciences: School of Computing Science
Thesis type: 
(Thesis) M.Sc.

Localization and assembly of the Vibrio cholerae type IV pilus secretin channel

Date created: 
2017-04-12
Abstract: 

Type 4 pili (T4P) are filamentous structures found on the surfaces of many Gram-negative bacteria, including Vibrio cholerae. The V. cholerae T4P are the toxin-coregulated pili (TCP), which mediate bacterial aggregation and exoprotein secretion, critical functions in colonization of the human intestine to cause the diarrheal disease cholera. TCP assemble at the inner membrane (IM), grow through a multiprotein conduit in the periplasm and through a secretin channel in the outer membrane (OM). The multimeric secretin channel is formed by secretin subunits, which are translocated across the IM by the Sec apparatus, and in most T4P systems, are transported to the OM with the help of a lipoprotein co-chaperone. In the V. cholerae TCP the secretin subunit itself, TcpC, is a lipoprotein, and its putative co-chaperone, TcpQ, is non-lipidated. Here we use mutagenesis, cellular fractionation and functional assays to investigate secretin channel assembly in V. cholerae. TcpC must be co-expressed with TcpQ to complement a ΔtcpC mutant in an assay of pilus functions, but the reciprocal is not true. TcpQ is necessary for pilus assembly but not for localization of TcpC to the outer membrane, demonstrating that TcpQ is not a co-chaperone for TcpC. The periplasmic domain of TcpC can be expressed on its own, localizes to the outer membrane, and localizes TcpQ at the outer membrane as well, provided TcpC is lipidated. When the periplasmic domain of TcpC is unlipidated it gets degraded and TcpQ accumulates in the periplasm, suggesting that the periplasmic domain of TcpC interacts with TcpQ and localizes it to the outer membrane via its lipid moiety. Our results lead to a model whereby TcpC Cys1 is lipidated at the IM by the Lgt machinery and transported to the OM in complex with TcpQ. TcpC inserts into the OM at two points: via its C-terminal portion, which forms a β-barrel channel with TcpC C-terminal domains of other secretin subunits, and via lipid moiety in its N-terminal domain, which interacts with TcpQ to link the OM channel to periplasmic pilus conduit.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Lisa Craig
Department: 
Science: Department of Molecular Biology and Biochemistry
Thesis type: 
(Thesis) M.Sc.

An underutilized resource: Investigating the role implementation of nurse practitioners in BC's primary care system

Author: 
Date created: 
2017-03-13
Abstract: 

Nurse practitioners (NP) are registered nurses who hold a Master’s degree in nursing and are trained to practise autonomously within a collaborative healthcare system. Extensive evidence indicates that NPs provide high-quality, patient-centred care; as a result, the BC Ministry of Health introduced the NP role in 2005 to help the province meet a growing demand for primary care. However, despite some targeted initiatives, NPs continue to be underutilized. Interviews with NPs and key stakeholders, coupled with a thorough literature review, are used to identify the barriers preventing NP role implementation in BC’s primary care system. While many barriers were identified, the absence of an appropriate funding mechanism was found to be the most significant barrier to NP role implementation, ultimately limiting their utilization in the primary care system. Policy recommendations centre on developing a sustainable funding model that allows NPs to practise autonomously in multiple primary care settings.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
John Richards
Department: 
Arts & Social Sciences: School of Public Policy
Thesis type: 
(Project) M.P.P.

Room to grow: Policy options for developing BC’s early childhood education workforce

Date created: 
2017-03-14
Abstract: 

The recruitment and retention of a qualified workforce of Early Childhood Educators (ECEs) is vital to ensuring the provision of high-quality early childhood education and care (ECEC). British Columbia faces chronic challenges of high turnover and workforce shortages in regulated center-based ECEC, with significant negative consequences for children, parents, educators, and BC’s population overall. Despite well-known historical problems, little research has investigated recent changes, or attempted to develop comprehensive workforce strategies specific to BC. This study seeks to address this gap, using a mixed methods approach of interview data, survey analysis, literature review, and statistical evidence to highlight causes and assess potential solutions in the current BC context. Evidence is found of recent worsening in BC’s early childhood educator workforce challenges. Findings confirm that persistent issues of low pay and poor social recognition remain major problems; highlighted also is a high proportion of small centres, weak workplace and institutional supports, and a recent trend of increased competition for qualified workers from education and health sectors. A set of policy options is systematically analyzed according to a set of criteria, and recommendations are presented.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Maureen Maloney
Department: 
Arts & Social Sciences: School of Public Policy
Thesis type: 
(Project) M.P.P.

Compliant flooring for fall injury prevention in long-term care

Date created: 
2017-03-06
Abstract: 

A promising strategy for reducing the incidence and severity of fall-related injuries in long-term care (LTC) is to decrease the ground surface stiffness, and the subsequent forces applied to the body parts at impact, through installation of compliant flooring. Evidence about the feasibility of compliant flooring in LTC is extremely limited. My PhD research addresses this gap by conducting a comprehensive, multimethod evaluation of compliant flooring. Specifically, I investigate the feasibility of compliant flooring for fall injury prevention in LTC by synthesizing the available evidence (study 1), determining the effects of compliant flooring on external hand forces exerted by LTC staff when pushing wheeled equipment (study 2), and examining the barriers to and facilitators of implementing compliant flooring as perceived by key stakeholders (studies 3 and 4). In my first study, I conducted a scoping review to describe the extent, range, and nature of research activity on compliant flooring, and to identify research gaps and directions for future research. I found compliant flooring is a promising strategy for preventing fall-related injuries from a biomechanical perspective. Additional research is required, however, to determine whether compliant flooring prevents fall-related injuries in real-world settings, is a cost-effective intervention strategy, and can be installed without negatively affecting workplace safety. My second study compared the effects of flooring system and resident weight on the forces required by LTC staff to push floor-based lifts used to transfer residents. Compared to the conventional lift, the motor-driven lift substantially reduced forces in all experimental conditions and thus may help to address risk of work-related musculoskeletal injury. My third study examined the feasibility of compliant flooring from the perspective of organizational-level LTC stakeholders. My interview findings provide new evidence about facilitators and barriers that stakeholders consider in deciding to install compliant flooring in LTC, such as staff’s openness (or resistance) to change and flooring performance. My fourth study sought input about compliant flooring from additional stakeholders through a symposium. My findings suggest that while stakeholders perceive compliant flooring to add value to the LTC setting, there also remain significant informational and financial barriers to the uptake of compliant flooring. Overall, my thesis should inform planners and architects in the development of safer environments for vulnerable older adults, and improve policies and programs for fall injury prevention in LTC.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Dawn Mackey
Department: 
Science: Department of Biomedical Physiology and Kinesiology
Thesis type: 
(Dissertation) Ph.D.

Neither hero, nor villain: Rudolf Kastner and the Cluj ghetto narratives

Author: 
Date created: 
2017-04-19
Abstract: 

In 1944 Rudolf Kastner made a deal with Adolf Eichmann to save 1685 Jews from deportations to Auschwitz, which led to one of the most contentious trials in Israel’s history in 1954. Kastner, a civil servant at the time sued one Michael Gruenwald for defamation, after Kastner was accused of being a collaborator due to his contentious deal. The claims that he saved those close to him from his hometown in Cluj, and the fact he allegedly did not warn Hungarian Jewry from their imminent deportation to Auschwitz led to the head judge Benjamin Halevi to proclaim that he had “sold his soul to the devil.” This thesis analyzes the means by which the stories of individuals from the Cluj ghetto, Kastner’s deal with Eichmann and eventually the trial and its political connections were narrowed down into the conceptual paradigm of the ‘victim­hero,’ as well as its wider implications in connection to Israeli and Jewish identity. The conceptual frameworks of identity, the impact of memory, and trauma are essentially used as foundations in order to examine why Kastner was and is vilified. By examining this affair this thesis ascertains how that very process played into wider conceptual frameworks.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Andre Gerolymatos
Department: 
Arts & Social Sciences: Department of History
Thesis type: 
(Thesis) M.A.

Surviving the courts: Improving how provincial courts respond to sexual assault cases

Author: 
Date created: 
2017-04-11
Abstract: 

This paper is concerned with how provincial courts respond to sexual assault cases, in light of their imperfect record on convicting perpetrators as well as their negative impact on the well-being of many survivors. I first conduct research to identify the causes of both these problems, and then I develop and assess several potential government policies to improve the court process. My research is informed by a literature review and eight interviews with victim support workers, advocates, academics, lawyers, and judges. I conclude that governments need to take multiple actions to address these problems, beginning with policies that specialize court actors and processes, educate judges, and inform survivors.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Maureen Maloney
Department: 
Arts & Social Sciences: School of Public Policy
Thesis type: 
(Project) M.P.P.

Intelligent Tutoring Systems and Learning Outcomes: Two Systematic Reviews

Author: 
Date created: 
2017-04-12
Abstract: 

Intelligent Tutoring Systems (ITSs) are computer programs that dynamically model learners’ psychological states to provide individualized instruction. ITSs have been developed for diverse subjects to help learners to acquire domain-specific, cognitive and metacognitive knowledge at all educational levels. In this thesis, I report on two studies conducted to examine the current state of the ITS field. The first study is a meta-analysis conducted on research that compared the outcomes from students learning from ITSs to those learning from non-ITS learning environments. It examines 107 studies, published prior to 2013, with a total of 14,321 participants. The results show that ITSs outperform teacher-led, large-group instruction (g = .42), non-ITS computer-based instruction (g = .57), and textbooks or workbooks (g = .35). However, no statistically significant difference was detected between learning from ITS and learning from individualized human tutoring (g = -.11) or small-group instruction (g = .05). The second study evaluates research on the relative effectiveness of Bayesian networks in constructing student models in ITSs, which involves 143 studies published between 1992 and 2014. The study explores how Bayesian network was adopted to support the development of student models, relative to its strengths and weaknesses in investigating learning constructs and their contributions to the effectiveness of BN student modeling. A number of implications are drawn with respect to the application of BN in ITS design. Both reviews provide evidence that ITSs are relatively effective tools for learning. Furthermore, ITS researchers are invited to reconsider three fundamental research questions that have been examined since the emergence of ITSs and how they contribute to and constrain advances in effective ITS design in light of developments in artificial intelligence research. Finally, recommendations for future research directions are provided to researchers in the ITS community.

Document type: 
Thesis
Senior supervisor: 
Philip Winne
John Nesbit
Department: 
Education: Faculty of Education
Thesis type: 
(Thesis) Ph.D.

Abandoned Mining Sites in British Columbia: Managing Environmental Liabilities

Date created: 
2017-03-08
Abstract: 

Mining is a core industry in British Columbia’s economy. However, the economic benefits of mining exploration, development, and production, have corresponding environmental risks and liabilities. To protect against the risk of public assumption of environmental liabilities, the Government of British Columbia collects financial securities for mine reclamation from proponents of mining operations. A gap between the amount of held financial securities and total estimated reclamation liability has characterized this policy for decades. This gives rise to disproportionate public exposure to mine reclamation liabilities. This study examines several policy approaches to reforming the approach to financial assurance. I examine four other jurisdictions, conduct interviews, and analyze quantitative data. The result is the articulation of three policy options, the advantages and disadvantages of which are presented. One option is recommended to provincial decision-makers as the best approach to reforming mine reclamation and financial assurance policy.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
J. Rhys Kesselman
Department: 
Arts & Social Sciences: School of Public Policy
Thesis type: 
(Project) M.P.P.

Predictive cues and fitness consequences of breeding phenology

Author: 
Date created: 
2017-04-10
Abstract: 

Individual variation in the timing of breeding in birds has been strongly linked to the fecundity, and by extension fitness of the individual. Despite this important relationship, our understanding of the determinants of timing of breeding is unclear. Photoperiod determines a window of opportunity for breeding, but small-scale variation within this window still has major fitness consequences. This thesis explores potential cues that might account for variation in individual timing decisions, and possible consequences of timing on offspring and future broods. First we assess how pre-breeding male social cues and the development of tipulid larva (prey) might determine the female’s timing of egg-laying. While many lab studies have demonstrated that the presence of a male partner is necessary for female gonadal development, our 3-year field studies found no effect of male behaviour on female breeding phenology or performance. This suggests that male song may not be an important supplemental timing cue. Next we explore potential consequences of timing on chick quality and multiple brooding behaviour. We demonstrate that somatic and physiological traits are more developed in chicks from earlier nests (first broods). We also document that physiological maturity, in the form of hemoglobin concentration, is related to fledgling flight ability. Although we show that second brood chicks maintain the same trajectory of development just prior to fledging, they may pay a higher cost in the form of oxidative stress. Finally we document that multiple brooding behaviour is unrelated to timing in our highly synchronous population, and instead relates to individual quality. Comprehensively, this thesis suggests that male social cues may not be important cues determining timing of breeding, and that the consequences of timing on offspring include maturity at fledging and oxidative stress, but not multiple brooding in our system.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Tony D. Williams
Department: 
Science: Biological Sciences Department
Thesis type: 
(Thesis) Ph.D.