VictorJuiz/thesis huggingface dataset:
Learning-based Control for Autonomous Mobile Robots

As mobile robots leave structured indoor environments to operate in challenging outdoor environments, their motion controllers require advanced techniques to mitigate the effects of unmodelled surface materials (e.g., snow, sand, grass), terrain topography (e.g., side-slopes, inclines), and complex robot dynamics. This thesis investigates learning-based control within the context of path-tracking autonomous mobile robots. Learning-based algorithms alleviate the need for significant engineering work in identifying and modelling all disturbances that a controller may be required to mitigate. Furthermore, they are capable of predicting and acting in anticipation of repeatable effects and disturbances not modelled prior to deployment. The learning-based algorithms reduce tracking errors, increase operational speed, and increase localization reliability. Specifically, the thesis presents four approaches: 1) Iterative Learning Control (ILC), 2) Learning-based Nonlinear Model Predictive Control (LB-NMPC), 3) Robust Min-Max LB-NMPC (MM-LB-NMPC), and 4) Robust Constrained LB-NMPC (RC-LB-NMPC). ILC generates an acausal feedforward signal that reduces the path-tracking errors using information from any previous trial. While the approach is computationally appealing, ILC typically assumes that the robot is initialized with identical initial conditions for each trial and tracking the same desired path (i.e., generalization is non-trivial). On the other hand, LB-NMPC is a technique that uses a learned process model directly, enabling interpolation and extrapolation from experiences. In this case, the current control action is obtained by solving a finite-horizon optimal control problem using the current state of the plant as the initial state at each time-step. Finally, this thesis investigates two recent results in Robust NMPC in order to guarantee controller stability throughout the learning process in spite of model uncertainty. For MM-LB-NMPC, the control problem is altered to optimize for plausible worst-case scenarios. For RC-LB-NMPC, tightened constraints are applied to nominal predictions such that all plausible predicted sequences satisfy the given constraints. The resulting RC-LB-NMPC algorithm is a robust, learning controller providing safe, conservative control during initial trials when model uncertainty is high and converging to high-performance, optimal control during later trials when model uncertainty is reduced with experience.

Advisor: Barfoot, Timothy
Schoellig, Angela
The Role of Standing and Travelling Waves in Stratosphere-troposphere Coupling

Upward wave activity flux in the mid-latitudes is a strong control on the strength and temperature of the stratospheric polar vortex in the Northern Hemisphere winter. In this thesis, the variability of upward wave activity flux is studied using the ideas of linear interference. This framework separates meteorological fields into a zonally asymmetric climatology-â the stationary waveâ and a wave anomaly. Fluxes are then decomposed into a linear term that measures the spatial coherence of the anomaly and the climatology and an additional nonlinear term. In order to determine the structure of the wave anomalies that interfere with the climatology, a novel spectral decomposition of wave disturbances into standing and travelling components is developed. Unlike previous methods, it explicitly accounts for the covariance between the two components. The decomposition is applied to planetary waves in the Northern Hemisphere winter. It is shown that standing waves explain the majority of the variance of the linear part of the upward wave activity flux. Furthermore, the connection between upward wave activity flux in the troposphere and the strength of the stratospheric polar vortex is shown to be primarily driven by standing waves amplifying and attenuating the climatological wave. The relationship between the linear and nonlinear parts of the upward wave activity flux is investigated. It is shown that there is a roughly quadratic relationship between the two when considering individual wavenumbers, and that this can act as an explanation for the positive skewness of the wavenumber-1 upward wave activity flux distribution. A statistical model is constructed which demonstrates that a westward tilted climatological wave is the key ingredient in having a positively skewed wave activity flux distribution. Last, the analysis is extended to consider the dynamics of tropospheric variability and weather extremes. The standing-travelling wave decomposition is applied to tropospheric weather variability in order to separate the slow and fast drivers of cold winter weather over eastern North America. It is found that standing waves driven from the tropics largely control the large-scale ridge-trough structure over North America, but that eastward travelling synoptic waves can strongly modify it on shorter timescales.

Keywords: Fourier analysis
general circulation
stratosphere-troposphere coupling
Advisor: Kushner, Paul J
Data Envelopment Analysis Models for a Mixture of Non-ratio and Ratio Variables

Performance comparison is a delicate business, even among organizations of the same kind. The simplest of all is usually the ratio of a single output to a single input. The problem lies in the fact that one aspect of the business could hardly represent the whole picture and the landscape the business is operating in. Businesses have complex structures and oer variety of products so it is only fair to take all into consideration to judge their performance against others in an industry. Data Envelopment Analysis (DEA) is one method suitable when there are multiple inputs and outputs to be considered. It is a non-parametric method conceptualized by Farrell in 1957. However, it was not untill 20 years later, that Charnes, Cooper and Rhodes brought this concept into practice by finding a way to realize this idea and make it work. The breakthrough came from the fact that under certain assumptions Farrell's idea could be formulated as a linear mathematical program (LP) which could be solved using the simplex and similar methods. One limitation of the existing DEA models is their inability to work with ratio variables because the linear combination of DMUs do not generally translate to linear combination of inputs and outputs in the ratio form. In this work, our contribution to the field includes extending Farrell's idea to include ratio inputs and outputs and operationalizing four models under variable returns to scale assumption. Three non-oriented models are formulated and linearized and one non-linear model is solved using a heuristic.

Keywords: Data Envelopment Analysis
Non-oriented Models
Performance measurement
Ratio Analysis
Ratio variables
Relative Efficicency
Advisor: Paradi, Joseph C
Advancing Astronomical Instrumentation: an Adaptive Optics Kinematic Study of z~1 Star-Forming Galaxies

This thesis has a dual focus on improving ground-based astronomical instruments and an observational study of distant star-forming galaxies to study galaxy formation and evolution. Of fundamental importance to this work are adaptive optics (AO) technology and integral field spectrographs (IFSs), both of which offer powerful means of studying high redshift galaxies. First, I describe the design and development of an instrument to characterize the vertical atmospheric turbulence using the SLODAR (SLOpe Detection and Ranging) method. This instrument was used in a campaign at Ellesmere island (∼ 80◦N) and determined that the site has half of the total turbulence residing in the ground layer (

Keywords: adaptive optics
astronomical instrumentation
galaxy dynamics
galaxy evolution
galaxy formation
integral field spectrograph
Advisor: Wright, Shelley A.
CEACAM3: Specific Innate Immunity

The bacterial species Neisseria gonorrhoeae remains one of the most prevalent bacterial causes of sexually transmitted infections. Gonorrhea is typically characterized by a painful purulent discharge and inflammation, the outcome of overzealous recruitment of neutrophils, phagocytic immune cells highly specialized in the detection and elimination of microbial pathogens. Although molecular mechanisms of gonococcal pathogenesis have been studied in great detail, the causes for the excessive inflammation and immunopathology that follow infection are still not clear. The human neutrophil-restricted innate immune receptor CEACAM3 has been previously shown to promote opsonin-independent uptake and killing of N. gonorrhoeae by neutrophils. In the course of my thesis work, I have established that the role of CEACAM3 is not restricted to the neutrophils’ direct engulfment and killing of gonococci, since it also drives a vigorous inflammatory response that typifies gonorrhea. By carrying the potential to mobilize increasing numbers of neutrophils, CEACAM3 represents a tipping point between the protective and pathogenic outcomes of N. gonorrhoeae infection. My biochemical profiling of gonococcal-infected, genetically modified neutrophils revealed that CEACAM3 engagement triggers a Syk-, PKCδ-, Bcl10-MALT1-, and Tak1-dependent signaling cascade that leads to the activation of an NF-κB-dependent transcriptional response, with consequent production of pro-inflammatory cytokines. I also showed that CEACAM cross-linking on neutrophils signals in synergy with TLR4, significantly amplifying the response to LPS, suggesting that CEACAM3 acts as an integral part of a complex innate immune detection network. Finally, I co-led a study that characterized Opa protein variant expression among a collection of clinical specimen-derived N. gonorrhoeae, and then assessed their CEACAM binding profile. This study suggested that mucosal infection in humans selects for binding to epithelial-expressed CEACAMs but against CEACAM3 binding in vivo. Together, my studies implicate a role for CEACAM3 as a host-adaptive innate receptor that promotes gonococcal detection and elimination in the context of natural infection, but also reveal potential pathogenic consequences of CEACAM3 activation.

Keywords: CEACAM
Neisseria
Neutrophil
Advisor: Gray-Owen, Scott
Chasing the Promise of Performance: A Case Study Exploring the Implementation of a Standards-Based Accountability Policy Intervention in the Ontario Public Health System

OBJECTIVE: This research project examines the development and implementation of Ontario’s system of public health accountability and performance management through two cross-cutting themes: control and results. This research project represents one of the first attempts to bridge the fields of public administration and new public management, policy implementation, and quality improvement in an examination of accountability and performance improvement in the public health sector. METHODS: This study involved semi-structured, in-depth interviews with informants in three public health units (n=20) and with representatives from the Ministry of Health and Long-Term Care (MOHLTC) (n=4). A web-survey of public health managers (n=53) was also carried out. Document review supplemented these two main data sources. Qualitative data were coded and analyzed using Atlas.ti 6.2 and quantitative data were exported to SPSS for descriptive and bivariate analysis. FINDINGS: Control, emphasizing compliance-based accountability, top-down implementation, and performance measurement for quality assurance had a dominant presence in policy development and implementation that negatively affected the pursuit of results (i.e. emphasis on performance, bottom-up implementation, and measurement for quality improvement). Pre-existing accountability structures challenged efforts to establish performance improvement as a key consideration. Despite evidence of consultation with the field, the MOHLTC’s exercise of final decision rights in policy development reinforced limitations on managerial discretion. Top-down implementation featured considerable conflict over the means of policy achievement (i.e. measurement components, resources, timelines, and some service protocols). Conflict was often met with concern amongst local public health informants over the prospective utility of performance information for improving population health outcomes. The province’s adoption of continuous quality improvement, presenting both barriers and facilitators, also confounded the prospect of substantial systemic improvement. CONCLUSION: This empirical examination of a nascent and evolving system of public health accountability and performance management strongly emphasized a control orientation with some elements supporting results. The bridging of these three fields and the application of these two cross-cutting themes provided a useful basis on which to understand public health accountability and performance improvement in Ontario. This approach merits use in future examinations of this or similar systems, particularly where performance output and outcome information is available.

Keywords: accountability
implementation
performance management
public health policy
quality improvement
Advisor: Schwartz, Robert
Navigating Bodies, Borders and the Global Game: An Ethnography of Youth, Football and the (Productive) Politics of Privation in Ghana, West Africa

This dissertation explores the precarity and politics of youth as it intersects with the game of football in postcolonial Ghana. Departing from scholarly assertions of a ‘crisis’ of youth in its masculine guise, the study is predicated on the lived experiences of a male youth citizenry excluded from the prosperous narrative of Ghana’s neoliberal state, and unable to procure the basic means to work, wage and wedlock. Drawing on multi-sited ethnographic fieldwork in southern Ghana, I ask of how this generation of peripheral male youth construct the game of football vis-à-vis the precarious nature of their societal ‘becoming’, and their broader quest to live productively through the fractured, crisis-ridden exigencies of these neoliberal times. Drawing on the metaphor-concept of the borderland, I proceed to argue that the game of football – both as a mediated form of global popular culture and a hegemonic masculine practice – has come to represent an alternative source of mobility and a most millenarian resolution to the ‘crisis’ of youth in its masculine and West African guise. I contend that the game now serves as a primary vehicle for utopian imaginaries of future amongst male youth in Ghana, where migration and the quest to ‘go outside’ have become fundamental features of a youth culture edging ever-further away from its former anchoring in Pan-African narratives. Ultimately, this project is an ethnography of the non-linear journeys that are enacted by male youth in their quest to become mobile out of Africa, and through their corporeal investment in the ‘global’ game. Stretching from the impoverished hinterlands of Accra to the insulated rural confines of one of West Africa’s premier football academies, it is an ethnography which speaks to the virile forging of personal biography amidst postcolonial history – its foremost contribution being to illuminate the productive politics of youth, agency and mobility as they manifest on the margins of the modern world.

Keywords: Agency
Ethnography
Football
Mobility
Poverty
Youth Masculinities
Advisor: Atkinson, Michael
Exploring the Effects of Higher Education Experiences on Male and Female STEM Majors' Attitude Towards Entrepreneurship

The purpose of this study was to assess how higher education experiences differently affect female and male STEM students' personal valuation about becoming an entrepreneur. The promotion of entrepreneurship has made its way onto the agendas of policymakers, students, and institutions of higher education. Nonetheless, most studies indicate that male students are significantly more likely than female students to express positive personal valuations about becoming an entrepreneur. The factors influencing this difference, however, are left unexamined. An understanding of how higher education experiences foster or deter interest in entrepreneurship is important for the success of campus-based entrepreneurship initiatives, and for ensuring equal opportunities for female student participation. Universities and colleges in the United States (US) have been at the forefront of efforts to foster student entrepreneurship. Using a series of ordinal logistic regressions on a multi-institutional sample of 871 four-year college and university students collected by the Wabash National Study in the US, I examine student attitudes towards becoming an entrepreneur, along with student responses regarding their higher education experiences on three different waves. Results show that on entering higher education male students are more likely than female students to view becoming an entrepreneur as important, and that this gap widens over time. Moreover, becoming an entrepreneur loses importance for both male and female students over time. This study also found certain personality traits and higher education experiences as significantly associated with studentsâ valuations of the importance of becoming an entrepreneur, namely the degree to which one enjoys engaging in effortful cognitive activities, exams and assignments that require higher-order thinking, and interactions with faculty. This study contributes to understandings of the relationship between higher education and entrepreneurship in several ways. First, the results of this study show that attitudes towards entrepreneurship are weakly associated with key personality traits, indicating that differences between male and female valuations of the importance of becoming an entrepreneur likely stem in part from social expectations and experiences. Second, the results from this study provide colleges and universities with evidence that certain practices may make a difference in the likelihood students will value as important becoming an entrepreneur. The conclusions of this study suggest that colleges and universities interested in promoting student entrepreneurship should be proactive in harnessing studentsâ entrepreneurial interests early in their higher education, when such interests are at their highest.

Advisor: Sรก, Creso
Stochastic Models in Operations Research with Applications to Financial Markets and Health Care Systems

In the first chapter, we study a double-sided queue with batch arrivals and abandonment. We assume there are two types of customers, patient ones who queue but may abandon, and impatient ones who depart immediately if their order is not filled. The system matches units from opposite sides of the queue using a FCFS policy. The model is applicable to alternative trading systems called crossing networks. We characterize, in closed-form, the steady-state queue length distribution and the system-level average system time and fill rate. For a customer who arrives to the system in steady-state, we derive formulae for the expected fill rate and system time as functions of her order size and deadline. We compare the system- and customer-level results from our model to a simulation and find a close correspondence. In the second chapter, we study a multistage, outpatient health care program culminating in elective surgery. We investigate current operational performance by determining how demographic factors, medical information and operational modifications affect attrition and system times. We develop a discrete-event simulation to model patient flow in the current system using data from the Bariatric Surgery Program at Toronto Western Hospital to estimate uncertainties in the simulation. We propose routing and priority policies based on information obtained from an intake questionnaire. We demonstrate that several policies decrease the average time patients spend in the system while not reducing throughput. We show that the policy with the largest system time reduction is robust to moderate amounts of type-I/II errors in the information provided by the questionnaire. In the third chapter, we investigate the scheduling practices of a multistage, outpatient health care program with no-show patients. Patients must undergo several assessments before completion. We formulate the problem as a Markov Decision Process and use approximate dynamic programming to find policies to schedule patients to appointments. We propose several heuristic policies and examine the quality of our solutions via structural results and by comparing them to a discrete-event simulation of the clinic. We apply our results to the operation of a bariatric surgery program at a large tertiary hospital in Toronto, Canada to determine how these policies can improve their operations.

Advisor: Milner, Joseph
Afeche, Philipp
Physiognomy as a Strategy of Persuasion in Early Christian Discourse

Abstract Ancient physiognomic thought held that the body and soul were intrinsically related, and that observation of a subject's physical appearance provided insight into his or her character. Beyond being a diagnostic tool, however, physiognomy was also used as a strategy of persuasion to bolster or malign an individual's character to an author or speaker's audience, and appears in a host of different ancient genres. However, with a few notable exceptions, the important role that physiognomic thought played in early Christian texts and discourse has not received the scholarly attention it warrants. The following addresses some of the different ways in which physiognomy was employed as a form of rhetoric by early Christians. It was utilized as a means of undermining or discrediting theological opponents or "heretics" on the one hand, but as a strategy for positive self-representation among their own detractors on the other. Some early Christians also used physiognomy to reinforce their understanding of Paul as a philosopher: the description of Paul's physical appearance in the Acts of Paul and Thecla is best understood as designed to evoke the image of the prototypical ancient philosopher in general, and Socrates in particular. Here the importance placed on "looking the part" of a given type of person in antiquity underlies this presentation. Related to this, this dissertation also addresses the phenomenon that arises when the opposite is the case, namely the conception of Jesus as being physically unattractive based on a literal interpretation of the suffering servant imagery in Isaiah. This dissertation demonstrates that physiognomic thought held important persuasive traction for early Christian authors negotiating boundaries and ideologies of group self-identity.

Keywords: Early Christianity
Physiognomy
Advisor: Kloppenborg, John