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Bayesian Nonparametric Estimation of Simpson's Index
No full textSimpson’s index is one of the oldest and most popular diversity indices. Traditionally,
Simpson’s index has been estimated using frequentist methods, although Bayesian
nonparametric estimation has been explored in recent years. Bayesian nonparametric
estimation is an attractive alternative to frequentist estimation because it provides a
theoretical framework for incorporating prior information while overcoming some of
the limitations of parametric Bayesian approaches. Specifically, nonparametric priors
do not require that we make an assumption about the true number of types in the
population, something that is often unknown.
This thesis introduces expressions for the bias, variance, and mean squared error for some existing Bayesian nonparametric estimators of Simpson’s index. These
estimators of Simpson’s index require the specification of a concentration parameter and/or a discount parameter, and so we discuss various strategies for selecting
these parameters. We also illustrate how these Bayesian nonparametric estimators
compare to the standard frequentist estimators in an empirical study. The findings
of this study indicate that the Bayesian nonparametric estimators with well-specified
parameters outperform the frequentist estimators in terms of mean squared error
Modeling and Experimental Characterization of Core Loss of A Switched Reluctance Machine
No full textCore loss significantly impacts the efficiency and thermal performance of Switched Reluctance Machines (SRMs), especially under high speeds. Conventional measurement methods are often inadequate for capturing losses in assembled stator cores, where flux paths are complex, and excitation waveforms are non-sinusoidal. This thesis addresses these limitations by developing and experimentally validating a practical core loss characterization method tailored for SRM stators. The study begins with a comprehensive review of core loss mechanisms and measurement challenges, highlighting the effects of manufacturing processes such as punching and welding on material properties. A core loss measurement method is introduced based on transformer induction theory, enabling time-domain reconstruction of magnetic field quantities from voltage and current waveforms. The method is validated using a ring core and SRM stator geometry with finite element analysis (FEA), replicating practical excitation conditions. An experimental setup is built with a fractional SRM stator core and custom magnetizing yokes. The experimental setup captures induced voltage and current waveforms from the stator. The proposed method is experimentally validated over a wide frequency range from 100 Hz to 10,000 Hz and under varying flux density levels, confirming the applicability for practical core loss characterization of SRM stators
CLOSED STRINGS
No full textA \df{closed string} is either of length one or contains a border that occurs only as a prefix and as a suffix of , without appearing elsewhere within . This thesis presents a fast and practical time algorithm to compute all closed substrings of a string . This is achieved by introducing a compact representation of all closed substrings using only space. Additionally, a simple and space-efficient approach is proposed to compute all maximal closed substrings (MCSs) using the suffix array () and the longest common prefix () array of .
Given a Fibonacci word , where , the thesis shows that the exact number of MCSs is , where is the golden ratio, and is the -th Fibonacci number. These results highlight novel combinatorial properties of closed substrings in structured sequences.
To complement the theoretical findings, an efficient implementation of the algorithms for computing closed strings and MCSs is provided. The implementation has been thoroughly tested and is designed to support practical applications, facilitating further exploration of closed substrings in various contexts
Tackling the Problem of Inability - A Barrier to Discharging Iris Marion Young's Conception of Political Responsibility
No full textIris Marion Young defines structural injustice as a moral wrong, distinct from traditional conceptions of moral wrongs that are traceable to or can be attributed to specific actions, individuals, or policies. This kind of injustice is generated and maintained by the ongoing, collective participation of millions of people acting together in shared systems and processes, often in ways that are not obviously morally (or legally) wrong. As such, Young argues for a new conception of responsibility to explain when we have political responsibility for injustice and how we should act to change these unjust outcomes, to which end she proposes the Social Connection Model (SCM). The SCM explains a forward-looking conception of political responsibility, generated by an agent’s social connection to injustice. Young claims that this responsibility should be discharged through collective action with others who share this responsibility.
Building on Young’s account, I argue the SCM provides important benefits towards collective approaches for addressing injustice. However, I suggest there is a present and pressing problem of inability: despite having this political responsibility, I argue that most agents do not presently have the ability to discharge this responsibility. To address this problem of inability, I suggest we ought to provide agents with a form of preparation to develop the required knowledge base and critical thinking skills to be able to recognize their political responsibility and take part in collective action to address injustice. I suggest that an important part of this preparation should take place in public education, grounded by both a citizen’s right and duty to be educated, as well as a democratic government’s responsibility to educate its citizens. I evaluate why education is the right place for this preparation to take place, examine what kind of education can produce this preparation, and question whether it is already underway.DissertationDoctor of Philosophy (PhD)Iris Marion Young’s social connection model (SCM) explains a forward-looking conception of political responsibility for structural injustice. This political responsibility is generated by an agent’s participation in the social processes and systems that produce this form of injustice. Despite the unique benefits that I argue the SCM makes towards tackling structural injustice, I also suggest that there is a present and pressing problem of inability. I argue that despite most contributing agents having responsibility to participate in collective solutions to address injustice, most do not presently have the necessary abilities to discharge this responsibility. My thesis outlines some of the important causes of this inability, and I suggest that providing citizens with a form of preparation can equip them to discharge their political responsibilities most effectively. I argue that this preparation should occur in public education, with curriculum that prioritizes cultivating democratically engaged and justice-oriented citizens
INVESTIGATION OF EDUCATIONAL OUTCOMES, DEVELOPMENTAL HEALTH, AND REGIONAL POLICY DIFFERENCES FOR YOUNG CHILDREN WITH NEURODEVELOPMENTAL DISORDERS IN CANADA
No full textEducational and developmental trajectories can be modified with early identification of needs and early interventions to support children in meeting developmental milestones. The goal of the dissertation was to explore the health and social outcomes of children with parent-reported, diagnosed, or teacher-identified neurodevelopmental disorders (NDD) in Canada. This was done through three studies: 1) a quantitative regression study on developmental and academic outcomes from kindergarten to Grade 6 in Ontario, 2) a realist review of literature from the last decade on child development programs in Ontario and Manitoba; 3) a quantitative multilevel model approach to examine changes in prevalence rates of developmental outcomes over time in neighbourhoods in Ontario and Manitoba. The identification of developmentally vulnerable subgroups in these studies could help stakeholders decide on where and how universal and targeted policy solutions could be implemented. These studies provide more empirical support for early intervention programs and early entry to special education to ensure students develop the skills they need. Meaningful participation in school, community, and home is important for child and family development, and these studies show that meaningful participation can be facilitated by healthcare and community providers, educators, policymakers, and parents themselves. Including two provinces in two of the three studies allowed us to compare provincial health and educational policies and describe possible ways interprovincial variance exists in services and childhood outcomes. The results also showed socioeconomic and geographic inequities experienced by families and neurodiverse children between and within provinces. Additionally, the dissertation shows that a diagnosis of either autism spectrum disorder (ASD) or other NDD is associated with varied developmental and educational outcomes. Fundamentally, this dissertation showcases the necessity for collaboration in child developmental health and education sectors to provide more seamless communication and support services across schools, clinics, and community agencies
The NIRPS CMF Subprogram
No full textTracing the compositional link between terrestrial super-Earths and their host stars provides clues to their dominant formation pathway. By constraining the stellar abundances of refractory elements, we can predict the core mass fractions (CMFs) of their super-Earths. The level of agreement between this prediction and the planet’s true CMF from their masses and radii can teach us about past formation processes, like mantle stripping and water-rich formation plus sequestration in the planet’s core. Here, we present the first results from the Near Infrared Planet Searcher’s (NIRPS) GTO CMF subprogram: an intensive radial velocity campaign to refine masses of transiting super-Earths and compute their host stellar abundances. We retrieve precise masses for three hot super- Earths around M dwarfs (GJ 1132 b, GJ 1252 b, and LTT 3780 b), calculating masses of 1.69 ± 0.15M⊕, 1.54 ± 0.18M⊕, and 2.34 ± 0.10M⊕ respectively. We measure the CMFs of these and five further hot super-Earths from the literature to 10-15% precision. We compare these to CMF predictions from measuring the Fe, Mg, and Si abundances of their host stars measured from the NIRPS spectra. We find that the CMFs of these planets are smaller than expected from their host stellar abundances, to a statistically significant degree. This discrepancy is suggestive of significant reservoirs of water, generally consistent with water mass fractions of ∼ 1%, sequestered inside the interiors of these planets
CHARACTERIZING FIBRE FERMENTING BACTERIA IN THE INFANT GUT MICROBIOME
No full textThe gut microbiome undergoes significant change over the course of infancy, transitioning from a sparse immature community to a more diverse mature community over the first 3 years of life. This maturation is thought to be mediated by the transition from an immature milk diet to an adult-like solid food diet, particularly through the consumption of complex oligosaccharides such as dietary fibres. However, to date there has been little examination of the effects of dietary fibre consumption on the infant gut microbiome. In this work, I investigated the influence of dietary fibre consumption during infancy on the composition and function of the fibre fermenting bacterial population of the infant gut microbiome across two study populations of infants. I applied a combination of 16s rRNA gene sequencing and shotgun metagenomic sequencing to determine whether the composition of the infant gut microbiome was influenced by fibre consumption. To assess the fibre content of the infant diet I used multiple descriptors of dietary fibre intake including: adherence to a plant foods based diet, calculated daily fibre consumption, and the introduction of solid foods. I showed that across these three descriptors of fibre consumption in the infant diet there were not large scale gut microbial community changes. Instead, the effects were limited to individual microbial taxa, largely those containing genes for the metabolism of dietary fibres. These fibre fermenting bacterial populations were consistently at higher abundance in populations consuming higher fibre diets than those consuming lower fibre diets, suggesting an increased ability to metabolize dietary fibres. However, the effects were also highly individual and varied between participants, likely due to the specifics of their diet. Together, this work shows that while the effects of dietary fibre consumption during infancy varies between individual, there is an increase in fibre metabolism following the increase in fibre consumption.ThesisDoctor of Philosophy (PhD)The gut microbiome increases in complexity over the course of infancy, becoming a more diverse mature community over the first 3 years of life. The introduction of solid foods, and particularly dietary fibres, are important to this maturation, however, to date there has been little examination of the effects of dietary fibre consumption on the infant gut microbiome. In this work, I investigated the influence of dietary fibre consumption during infancy on the composition and function of the infant gut microbiome. I showed that fibre consumption in the infant increased the abundance of fibre fermenting bacterial species, potentially increasing the function of the community. Together, this work shows that while the effects of dietary fibre consumption during infancy varies between individual, there is an increase in fibre metabolism following the increase in fibre consumption
Dust Evolution And Concentration In Disk Wind-Driven Protoplanetary Disks
No full textBoth observations and simulations over the last decade have shown that turbulence is less
influential than previously thought in governing the dynamics of protoplanetary disks.
Magnetized disk winds have instead emerged as the most important mechanism in pro-
toplanetary disk evolution and must therefore be considered at every step of the planet
formation process. The very first steps of planetary system formation, the growth of dust
from micron-sizes to km-size planetesimals, are still a subject of debate. The tremen-
dous gains in mass from one regime into the next implies that dust growth in disks must
be both quick and efficient, requiring both effective growth by collisional interactions
and high concentrations that can trigger rapid planetesimal formation via streaming
instability. In this work, I study dust growth within a wind-driven protoplanetary disk
model whose properties are informed by current observational constraints. I study the
parameter space of turbulence strengths, wind-driven accretion strengths, wind-driven
outflow strengths and accretion rates in a search for disks conducive to planetesimal
formation. I find that even though wind-driven disks are more conducive to both dust
growth and concentration compared to turbulence-driven disks, the streaming instability
threshold is only crossed for the least turbulent disks with the most powerful outflow.
While planetesimal formation in smooth, wind-driven disks is therefore possible in rare
cases, dust concentrations into pressure bumps appear to be vital in the formation of
planetary systems.Dr. Ralph E. Pudrit
Using Boundary Objects for Continuous Compliance in Automotive Development
No full textOne of the main challenges in multidisciplinary environments, such as in automotive Original Equipment Manufacturers (OEMs), is managing rapid development timelines while ensuring functional safety. To keep track of development, project managers and engineers employ various tools and methodologies. However, sharing and managing data from different frameworks raises new challenges, particularly in ensuring that safety obligations defined by standards such as ISO 26262 remain traceable and actionable throughout the development life-cycle.
In this thesis, we introduce an approach that combines model-based engineering and the boundary objects methodology to link standard-driven safety activities with agile software development practices. The boundary object serves as a structured intermediary that captures safety-relevant constraints and mandated work products while translating them into concrete engineering tasks used in agile project management tools. This approach helps reduce the risk that safety-critical considerations are overlooked in fast-paced development environments and supports clearer communication between safety engineers and development teams.
To evaluate the approach, we apply it to a safety analysis workflow for an automotive propulsion system, demonstrating its ability to support compliance-related activities associated with ISO 26262 without disrupting agile routines. The results indicate that the use of boundary objects improves traceability between safety artifacts and engineering tasks, assists in organizing safety assessments, and reduces manual effort when adapting safety activities to changing project needs. Additionally, the metamodel proposed in this work is already operational with JIRA and GitHub and is designed to allow future integration with other agile tools, making it adaptable across different development ecosystems.
By representing key safety assurance activities within a structured boundary object, this research provides a scalable method for supporting ongoing compliance needs in agile automotive development. The findings suggest that this approach improves traceability and aligns safety activities more effectively with development tasks while preserving the pace of agile development