VictorJuiz/thesis huggingface dataset:
Reach Control Problems on Polytopes

As control systems become more integrated with high-end engineering systems as well as consumer products, they are expected to achieve specifications that may include logic rules, safety constraints, startup procedures, and so forth. Control design for such complex specifications is a relatively unexplored research area. One possible design approach is based on partitioning the state space into polytopic regions, and then formulating a certain control problem on each polytope, with the intention that the set of all controllers so obtained would collectively achieve the specification. The control problem which must be solved for each polytope is called the reach control problem, and it has been identified as turnkey to the further development of this approach. The reach control problem (RCP) is to find a state feedback to make the closed-loop trajectories of an affine (or linear) control system defined on a polytope reach and exit a prescribed facet of the polytope in finite time. This dissertation studies a number of aspects of the reach control problem, and it uses tools from convex analysis, nonsmooth analysis, and computational geometry for this study. The dissertation has three main themes. First, we formulate and solve a variant of RCP in which trajectories exit the polytope in a monotonic sense; this provides a triangulation-independent solution of RCP. Second, we develop a Lyapunov-like theory for verifying if RCP is solved using a given candidate controller. This involves the introduction of the notion of generalized flow functions, a LaSalle Principle for RCP, and several converse theorems on existence of generalized flow functions. Third, we study the relationship between affine feedbacks and continuous state feedbacks for RCP on simplices. Although the two feedback classes have been shown to be equivalent under an assumption on the triangulation of the state space, we show by a counterexample that the equivalence is no longer true under arbitrary triangulations. Then we provide for single-input systems a constructive method for the synthesis of multi-affine feedbacks for RCP on simplices.

Keywords: Control for Complex Specifications
Hybrid Systems
Piecewise Affine Feedbacks
Reach Control Problems
Safety Constraints
Feedback Synthesis
Advisor: Broucke, Mireille E.
Nonlinear Quantum Optics in Artificially Structured Media

This thesis presents an analysis of photon pairs generated via either spontaneous parametric downconversion or spontaneous four-wave mixing in channel waveguides as well as in microring resonators side-coupled to channel waveguides. The state of photons exiting a particular device is calculated within a general Hamiltonian formalism that simplifies the link between quantum nonlinear optics experiments and classical nonlinear optics experiments. This state contains information regarding photon pair production efficiency as well as modal and spectral correlations between the two photons, characterized by a two-dimensional spectral distribution function called the biphoton wave function. In the limit of a low probability of pair production, photon pair production fficiencies are cast into forms resembling corresponding well-known classical nonlinear optical frequency conversion efficiencies, making it easy to see what plays the role of a classical “seed” field in an un-seeded (quantum) process. This also allows photon pair production efficiencies to be calculated based on the results of classical nonlinear optical experiments. It is further calculated that, unless enerated photons are collected over a very narrow frequency range, their generation efficiency does not scale the same way with device length in a channel waveguide, or resonance quality factor in a microring resonator, as might be expected from the corresponding classical frequency conversion efficiency. Although calculations do not include self- or cross-phase modulation, nor two-photon absorption or free-carrier absorption, it is calculated that their neglect is justified in the low pair production probability limit. Linear (scattering) loss is also neglected, though partially addressed in the final chapter of this thesis. Biphoton wave functions are calculated explicitly, such that their shape and orientation, including approximate analytic expressions for their widths, can easily be determined. This further allows estimation of the suitability of their associated photon pairs for various quantum information processing applications. As an alternative to dispersion engineering a channel waveguide photon pair source, it is calculated that microring resonators can very naturally produce nearly spectrally uncorrelated photon pairs, which behave very much like idealized single-mode photons and are thus useful for applications involving the interference of photons from multiple sources.

Keywords: Nonlinear
Quantum
Optics
Theory
Integrated
Photonics
Advisor: Sipe, John E.
Helmy, Amr S.
James, Daniel
Disadvantaged Groups in the Labour Market: Older Workers, Younger Workers, and Nonstandard Workers

This dissertation examines four disadvantaged groups in the labour market from a variety of perspectives. Specifically, I looked into older workers, younger workers, nonstandard workers and female workers. In the first chapter, I examine the effects of Ontario eliminating mandatory retirement in 2006 on the labour force participation of older workers and the unemployment of younger workers. My second chapter examines the relationship between nonstandard employment and the subsequent workplace profitability. In my final chapter, I examine the interaction effect of employment status and gender on the issue of work hour mismatches. The first chapter examines the impact of recent labour policy change at a national/provincial level. I find positive and significant effects for the labour force participation rate of older workers in Ontario in the five years following the legislation change of banning mandatory retirement in Onatrio. Similar results are found for both men and women; however, the magnitude of this effect is somewhat smaller for men. In addition, the empirical analysis also reveals a short-run rise in the unemployment rate of younger workers. The second chapter examines the financial implication of nonstandard employment at an organizational level. The results suggest that nonstandard employment is positively associated with subsequent workplace profitability, after controlling for factors that might also affect profitability. Moreover, this significant positive relationship between nonstandard employment and subsequent profitability is primarily driven by capital intensive manufacturing, the real estate/rental/leasing, the retail/trade/consumer service, and the education and health services industries as well as smaller workplaces. Larger workplaces and the rest of the private sector do not display significant results. The final chapter looks into how employment status and gender systematically impact work hour preferences at an individual level. The findings indicate that there is a significant interaction effect between nonstandard employment and gender. Female nonstandard workers prefer to work more hours. Male workers, both nonstandard and standard, are more likely to prefer to work fewer or the same hours. These results conform to labour market trend of increasing labour force participation rates of females and a declining trend among males.

Keywords: Nonstandard Employment
Profitability
Mandatory Retirement
Work Hour Mismatch
Female workers
Older workers
Younger workers
Advisor: Reid, Frank
Verma, Anil
An Investigation of Professional Development of the Apprenticeship and Trades Professoriate in Two Ontario Colleges

This thesis is an exploratory investigation of how apprenticeship instructors in two of Ontario's colleges perceive and have experienced professional development over the duration of their careers and the role their employer-colleges, played in that professional development. As the primary agents for skills and knowledge transfer, the instructors of apprenticeship training provide a key role in preparing competent, skilled-trade workers for a complex and changing work environment. This research is relevant at this time because of the many changes to the Colleges of Applied Arts and Technology since their inception in the mid-nineteen- sixties. The original mission of the colleges, to deliver occupation preparation programs has evolved to a much-expanded mandate to include degree granting. Other changes include a much more diverse student population with diverse needs, backgrounds and values. Have the apprenticeship instructors received the requisite training and development to deal with changes in technology, student needs, teaching and learning strategies and the evolving complexities of the college environment? This study contributes to the literature of professional development in the apprenticeship professoriate by examining the perceptions, attitudes and behaviours concerning professional development. The findings reveal that there are issues of physical location, discourse and methods of instruction, unique to apprenticeship training, which have a profound impact on the apprenticeship instructors' disposition and participation in professional development. Data were attained from a series of in-depth interviews, which revealed that the apprenticeship instructors are a dedicated and motivated group of educators who are committed to providing the highest quality of education to their students. However, the professional development offered or supported by the college-employers attracts very little, if any, participation by the apprenticeship professoriate. The findings indicate that changes to facilitate the active participation in professional development, creating a more inclusive environment between the apprenticeship instructors and other faculty members and restructuring the professional development programs to include review and evaluation of every faculty member's needs would create a more comprehensive and continuing enhancement of instructors' capabilities and student learning outcomes.

Keywords: Apprenticeship
Professional Development
Instructors
Professors
Advisor: Jones, Glen A.
Competitiveness by Design: An Institutionalist Perspective on the Resurgence of a 'Mature' Industry in a High Wage Economy

This thesis examines the learning dynamics underpinning the resurgence of Canada's office furniture manufacturing sector, which underwent dramatic growth following its near collapse in the wake of the North American trade liberalization beginning in the late 1980s. It investigates the role that design and quality have played in prompting a move up-market and enhancing the sector's competitiveness. It also focuses on other leaning processes that drive economic growth, looking at attempts to transfer workplace practices from Continental Europe to Canada, as well as the institutional obstacles that shape and constrain these processes. Finally, it examines how furniture firms learn from their customers, and the key role played by market intermediaries such as sales agents, dealers, interior designers, and architects in linking producers with consumers as well as influencing the final furniture product. The learned behaviour hypothesis that is central to this thesis suggests that globally competitive firms operating in a Canadian institutional context prosper by learning how to produce (i.e. industrial practices and processes) and what to produce (i.e. design-intensive, high quality products) from the above sources that are both internal and external to the manufacturing firm. The scope of research considers the social and organizational practices through which manufacturing knowledge is integrated into innovation processes, as well as their dynamics, spatiality and temporality, the institutional forces that shape the skills, training, tenure and design dimensions of a high performance workplace, and the mechanisms and conditions that mediate the transfer of manufacturing knowledge at a distance. The empirical analysis entails a mixed-methods approach including a survey questionnaire and in-depth interviews with industry experts. The analysis contributes to core debates in economic geography and the social sciences concerning the role of proximity and distance in innovative production, and the structure / agency debate. In summary, it finds that economic growth in the office furniture sector in Canada is dependent upon not only local knowledge networks and flows but also global sources of innovation and competitive advantage. It also advances an agency-centered institutionalist economic geography by showing that institutions interact in complex ways with the decision-making of economic actors to shape local labour dynamics and the behaviour of firms.

Keywords: economic geography
institutions
labour market practices
design
manufacturing
innovation
knowledge transfer
learning
user-producer interaction
industrial practices
agency
Advisor: Meric, Gertler
Development of Plasma Sprayed Composite Cathodes for Solid Oxide Fuel Cells

Atmospheric plasma spraying is attractive for manufacturing solid oxide fuel cells (SOFCs) because it allows functional layers to be built rapidly with controlled microstructures. The technique allows SOFCs that operate at low temperatures (600 to 750°C) to be fabricated by spraying directly onto robust and inexpensive metallic supports. Processes were developed to manufacture metal-supported SOFC cathodes by axial-injection plasma spraying. Cathodes consisted of LSCF (La0.6Sr0.4Co0.2Fe0.8O3-δ) or SSC (Sm0.5Sr0.5CoO3) as the primary material. Initially, the plasma spray process parameters were varied, and x-ray diffraction analyses were performed on the cathode coatings to detect material decomposition and the formation of undesired phases. These results determined the envelope of plasma spray parameters in which coatings of LSCF and SSC can be manufactured, and the range of conditions in which composite cathode coatings could potentially be manufactured. Subsequently, composite cathodes were fabricated by mixing up to 40 wt. % of the ionic conducting SDC (Ce0.8Sm0.2O1.9) material into the feedstock. The deposition efficiencies of these cathodes were calculated based on the mass of the sprayed cathode. Particle surface temperatures were measured in-flight to enhance understanding of the relationship between spray parameters, microstructure, and deposition efficiency. Electrochemical impedance spectroscopy was performed in symmetrical cells: at 750°C, LSCF-SDC cathodes had polarization resistances as low as 0.101 Ωcm², and SSC cathodes had polarization resistances as low as 0.0056 Ωcm². Finer mixing of the ceramic phases was achieved by using a nano-structured feedstock that contained both LSCF and SDC phases agglomerated together in larger particles. Fuel cells containing a yttria-stabilized zirconia (YSZ) electrolyte and a nickel-YSZ anode were fabricated, and the effect of the cathode microstructure on cell impedance was studied using the analysis of differential impedance spectra. The degradation of composite LSCF-SDC cathodes on porous 430 stainless steel supports was also investigated. To reduce degradation, La2O3 and Y2O3 reactive element oxide coatings were deposited on the internal pore surfaces of the metal supports. As a result, polarization resistance degradation rates as low as 0.00256 Ω·cm2 /1000 h were observed over 100 hours on coated substrates, compared to 0.1 Ω·cm2 /1000 h on uncoated substrates.

Keywords: solid oxide fuel cell
fuel cell
cathode
composite
plasma spray
LSCF
SSC
Advisor: Kesler, Olivera
Towards Robust Quantification of Cosmological Errors

The method of baryon acoustic oscillation (BAO) is among the best probes of the dark energy equation of state, and worldwide efforts are being invested in order to perform measurements that are accurate at the percent level. In current data analyses, however, estimates of the error about the BAO are based on the assumption that the density field can be treated as Gaussian, an assumption that becomes less accurate as smaller scales are included in the measurement. It was recently shown from large samples of N-body simulations that the error bars about the BAO obtained this way are in fact up to 15-20 per cent too small. This important bias has shaken the confidence in the way error bars are calculated, and is motivating developments of analyses pipelines that include non-Gaussian features in the matter density fields. In this thesis, we propose general strategies to incorporate non-Gaussian effects in the context of a survey. After describing the high performance N-body code that we used, we present novel properties of the non-Gaussian uncertainty about the matter power spectrum, and explain how these combine with a general survey selection function. Assuming that the non-Gaussian features that are observed in the simulations correspond to those of Nature, this approach is the first unbiased measurement of the error bar about the power spectrum, which simultaneously removes the undesired bias on the BAO error. We then relax this assumption about the similitude of the non-Gaussian natures in simulations and data, and develop tools that aim at measuring the non-Gaussian error bars exclusively from the data. It is possible to improve the constraining power of non-Gaussian analyses with `Gaussianizations' techniques, which map the observed fields into something more Gaussian. We show that two of such techniques maximally recover degrees of freedom that were lost in the gravitational collapse. Finally, from a large sample of high resolution N-body realizations, we construct a series of weak gravitational lensing distortion maps and provide high resolution halo catalogues that are used by the CFTHLenS community to calibrate their estimators and study many secondary effects with unprecedented accuracy.

Keywords: Dark Matter
N-body simulations
Baryonic Acoustic Oscillations
Weak Lensing
Advisor: Pen, Ue-Li
An In-vivo Exploration of Skeletal Mechanosensitivity and Associated Fragility in a Canadian Cohort of Women

The function of skeletal adaptation to mechanical load is to adjust the amount and distribution of bone tissue (geometry); such that stresses experienced within the bone are kept within certain physiological limits and fractures are prevented. Genetic, environmental or hormonal factors may cause heterogeneity in this adaptive response, altering geometry and consequently fragility. The purpose of this thesis was to explore the skeletal response to load in vivo, by evaluating stress at the hip under three different conditions: FRACTURE (Study 1), DIABETES (Study 2) and ESTROGEN deficiency (STUDY 3). We studied women 25 years of age or older who participated in the Canadian Multicentre Osteoporosis Study and had available Hip Structure Analysis (HSA) data from baseline dual energy x-ray absorptiometry (DXA) scans. Women were categorized according to fracture status (fracture or no fracture), diabetes status (diabetes or no diabetes) and estrogen use (current users or never users). We computed stress (megapascals=MPa) at the infero-medial margin of the femoral neck in a one-legged iii stance using a 2-D engineering beam analysis. We used linear regression to determine associations between femoral neck stress and each categorical variable. Study 1 (n=2168) demonstrated higher stresses in postmenopausal women with fractures compared to women without fractures (10.57 ± 2.19 vs. 10.30 ± 2.03 MPa; p=0.0031). Study 2 (n=3665) demonstrated higher stresses in women with Type 2 Diabetes Mellitus compared to non-diabetic women (10.98 ± 2.33 vs. 10.57 ± 2.20 MPa; p=0.0194). Study 3 (n=2447) demonstrated higher stresses in postmenopausal women not on estrogen than in premenopausal women (10.66 ± 2.14 vs. 10.09 ± 2.01 MPa; p<0.0001), but no differences in stresses between postmenopausal women on estrogen and premenopausal women (10.16 ± 2.00 vs. 10.09 ± 2.01 MPa; p=0.6102). Since stress is an indicator of underlying geometry, and geometry should be adapted to prevalent loads, higher stress indicates weaker geometry and suggests an impaired modeling response in these three conditions. Compromised modeling has important clinical implications in terms of treatment selection, as individuals with reduced load sensitivity may respond best to metabolic agents that would improve modeling responses to load stimuli.

Keywords: bone
osteoporosis
stress
hsa
mechanical load
postmenopausal
femur
DXA
Advisor: Jamal, Sophie
Thomas, Scott
Intraspecific Variation in the Populus balsamifera Drought Response: A Systems Biology Approach

As drought can impinge significantly on forest health and productivity, the mechanisms by which forest trees respond to drought is of interest. The research presented herein examined the intra-specific variation in the Populus balsamifera drought response, examining the potential role of the transcriptome to configure growth, metabolism and development in response to water deficit. Amassing evidence indicates that different species of Populus have divergent mechanisms and Three lines of inquiry were pursued to investigate the intraspecific variation the drought response in P. balsamifera. First, the transcriptome responses of six genotypes of P. balsamifera were examined using Affymetrix Poplar GeneChips under well-watered and water-deficit conditions. A core species-level transcriptome response was identified. Significantly, intraspecific variation in the drought transcriptome was also identified. The data support a role for genotype-derived variation in the magnitude of P. balsamifera transcriptome remodelling playing a role in conditioning drought responsiveness. Second, the impact of drought-stress induced declines in stomatal conductance, as well as an alteration in stomatal development in two genotypes was examined. Patterns of transcript abundance of genes hypothesised to underpin stomatal development had patterns congruent with their role in modulation of stomatal development. These results suggest that stomatal development may play a role as a long-term mechanism to limit water loss from P. balsamifera leaves under conditions of drought-stress. Finally, the drought-induced metabolome of six P. balsmaifera genotypes was interrogated. Metabolite profiling reveled amino acids such as isoleucine and proline and sugars such as galactinol and raffinose were found with increased abundance, whereas TCA intermediates succinic and malic acid were found with decreased abundance in response to drought. Comparative analysis of the metabolome and the transcriptome revealed genotypic-specific variation in energy and carbohydrate metabolism. Taken together, the findings reported in this thesis form a foundation to understand the basis of intraspecific variation in the drought response in P. balsamifera. Transcripts and metabolites that contribute to within-species differences in drought tolerance were defined. These molecular components are useful targets for both future study, as well as efforts aimed at protecting and growing trees of this important species under challenging environmental conditions.

Keywords: Populus balsamifera
System biology
Transcriptome
Drought
Metabolome
Stomata
Advisor: Campbell, Malcolm M.