VictorJuiz/thesis huggingface dataset:
Nondestructive Evaluation of Pre-stressed Concrete Cylinder Pipe by Resonance Acoustic Spectroscopy: Theoretical and Modelling Considerations

The theoretical basis for adapting the technique of resonance acoustic spectroscopy (RAS) for the purposes of inspecting buried, in-service water mains composed of prestressed concrete cylinder pipe (PCCP, lined-type) is presented in this thesis. The proposed nondestructive evaluation (NDE) technique is sensitive to degradation of the outermost layer (a protective mortar coating) of PCCP which occurs over only part of the pipe’s circumference. The frequency spectrum of healthy pipes is evaluated through a sequence of experimental measurements and finite element modelling studies (modal analyses). Several simplifying assumptions about the vibratory response of PCCP are gleaned from the modal analysis of healthy pipes, facilitating the development of a model of buried, water filled sections of pipe subject to varying degrees of damage. The model treats the pipe as a multilayered cylinder in plane strain condition and is solved via a transfer matrix (T-Matrix) method which has been extended by the author to accommodate non-axisymmetric elastic parameters (to represent pipe damage) and coupling to media external to the pipe (to represent coupling to soil and water). The model is then used to assess the effects of coupling to the surrounding soil, as well as the effects of increasing levels of mortar damage. From the results of these investigations, a novel damage metric called the asymmetry index is defined. This metric is appropriate for assessing damage to the protective mortar coating, and is based on the splitting of degenerate flexural modes which occurs when the axial symmetry of a pipe section is perturbed. Finally, a procedure for collecting and processing the resonant spectra from pipes in the field is presented. This procedure allows for the asymmetry indices associated with different vibrational modes to be computed at various axial locations along the pipeline thus providing a map of mortar damage along the water main. The primary advantage of the proposed technique is that it does not require precise knowledge of the pipe’s dimensions or elastic parameters. In addition, the technique is applicable for any type of surrounding soil.

Keywords: Multilayered Cylinders
Nondestructive Evaluation
Pre-stressed Concrete Cylinder Pipe
Resonance Acoustic Spectroscopy
Advisor: Sinclair, Anthony N
Sweepouts of Riemannian Surfaces

We consider a problem of subdividing and sweeping out Riemannian 2-surfaces by short curves and cycles. We prove that for every Riemannian 2-disc or 2-sphere M there exists a sweepout of M by based loops whose length is bounded in terms of area, diameter and boundary length of M. We provide nearly optimal bounds for the lengths of curves in a sweepout and use it to obtain curvature-free upper bounds for lengths of simple closed geodesics on a 2-sphere. This is a joint work with A. Nabutovsky and R. Rotman. In the third chapter we construct a sequence of metrics on a closed surface M, such that M has small diameter, but the maximal length of a curve or 1-cycle in an optimal sweepout of M is arbitrarily large. In the fourth chapter we show that every Riemannian surface M diffeomorphic to a sphere with k ≥ 0 holes admits a Morse function whose fibers are bounded by 52√Area(M)+length(∂M). We also show that on every 2-sphere there exists a simple closed curve of length ≤ 26√Area(S2) subdividing the sphere into two discs of area ≥ 1/3Area(S2) . In the fifth chapter we consider a problem of sweeping out a closed surface M by high parametric families of short 1-cycles. We construct a family of 1-cycles with Z2 coefficients on M that represents a non-trivial element of the k'th homology group of the space of cycles and such that the mass of each cycle is bounded above by Cmax{√ k,√g}√Area(M). This result is optimal up to a multiplicative constant. In the last chapter we show that if there exists a sweepout of a Riemannian 2-sphere M by curves of length less than L then it is possible to construct a slicing of M by simple curves which do not intersect and such that their length is also bounded by L. This is a joint work with Gregory R. Chambers.

Keywords: geodesic
Riemannian geometry
sweepout
width
Advisor: Nabutovsky, Alexander
Rotman, Regina
Confidence Men: The Mediterranean Double-cross System, 1941-45

This dissertation provides an analysis of the Mediterranean double-cross system of the Second World War, which was composed of a number of double agents who were turned by the Allies and operated against their ostensible German spymasters. Utilizing many freshly released archival materials, this study assesses how the double-cross system was constructed, why it was an effective instrument, and how it contributed to Allied success in two areas: security and counter-intelligence, and military deception. The focus is thus on both organization and operations. The chapters cover three chronological periods. In the first — 1941-42 — the initial operational usage of a double agent is assessed, along with the development of early organizational structures to manage and operate individual cases as components of a team of spies. The second section, covering 1943, assesses three issues: major organizational innovations made early that year; the subsequent use of the double agent system to deceive the Germans regarding the planned invasion of Sicily in July; and the ongoing effort to utilize double agents to ensure a stable security and counter-intelligence environment in the Mediterranean theatre. The third and final section analyzes events in 1944, with a focus on double-cross deception in Italy and France, and on the emergence of more systematic security and counter-intelligence double-cross operations in Italy and the Middle East. The dissertation demonstrates both the strengths and weaknesses of this double agent network, and its contribution to Allied success in the Mediterranean. It also establishes the double-cross system’s position as an integral component of the larger Allied intelligence victory in the Second World War, by analyzing its relationship with cryptanalysis, with the broader intelligence imperatives of MI5 and MI6, and with the German intelligence officers who were essential, if unwitting, collaborators in the system which allowed the Allies to control a substantial segment of the German spy network in the Mediterranean.

Keywords: Counter-intelligence
Double Agents
Espionage
Military Deception
Security
Advisor: Smyth, Denis
Stochastic Analysis of Cooperative MIMO Techniques for Downlink Interference Mitigation in Wireless Cellular Networks

Interference is one of the key factors limiting the performance of wireless cellular networks with dense base-station (BS) deployments. This thesis studies two prominent techniques for interference mitigation and improving data rates of cellular networks referred to as: (1) network multiple-input multiple-output (MIMO) and (2) large-scale MIMO (LS-MIMO). The primary objective is to analyze the benefits and limitations of these two schemes in the downlink of a cellular system that comprises multiple-antenna BSs and single-antenna users, adopts zero-forcing beamforming, and employs equal power allocation. There are three parts to this thesis. The first part develops an analytical tool to study the cooperation gain of network MIMO systems with disjoint clusters. It is shown that network MIMO has two major limitations. First, due to the need to perform zero-forcing from a distributed set of BSs, a network MIMO system introduces a penalty in terms of the received signal power. Further, users located closer to the cluster boundaries are prone to significant interference, which considerably constrains system performance. The next two parts of this thesis propose solutions for these limitations. The second part shows that the signal power penalty can be mitigated if the LS-MIMO technique is adopted for interference mitigation. In particular, we prove that an LS-MIMO system is superior to a comparable network MIMO system for a wide range of utility functions. In the final part of this thesis, an alternative BS clustering termed as user-centric clustering is considered. Under this clustering strategy, BS clusters are formed for each user independently. Consequently, cluster boundaries no longer exist. We quantify the performance of an LS-MIMO system with user-centric clustering, and explore different avenues in which such a clustering scheme brings significant performance gains. Further, the tradeoff among providing sum-rate multiplexing, diversity, and interference cancellation in such a system is studied. It is shown that a close-to-optimal strategy for maximizing the per-BS ergodic sum rate is to use none of the spatial resources for interference cancellation, while selecting the number of users to schedule and diversity order per user properly.

Keywords: Large-Scale MIMO
Network MIMO
Stochastic Analysis
Wireless communications
Advisor: Yu, Wei
Adve, Raviraj S
Time-lapse Ultrasonic Imaging of Elastic Anisotropy in Saturated Sandstone under Polyaxial Stress State

Although true-triaxial test (TTT) of rocks is now more extensive worldwide, stress-induced heterogeneity is not accounted for and usually simplified anisotropic models are used. Data from a TTT on a cubic sample of Fontainebleau sandstone is used in this study to evaluate our velocity imaging methodology. An anisotropic P wave velocity tomography method was developed using a geometrical approach based on an ellipsoidal P wavefront surface. During the two non-damaging phases of the experiment, saturation of the rock sample with water resulted in inaccurate tomographic images; however, during the final elasto-plastic phase of the experiment comprising major AE activities, tomographic images demonstrated reasonable anomalies. Thus, the P-S1-S2 velocity survey was utilized to obtain an accurate and reliable velocity image of the sample during the two non-damaging phases. This was accomplished using a numerical investigation by FLAC3D on the non-uniform distribution of stress over the sample to estimate the compaction pseudo-boundary surfaces within the rock. Thus, the problem of breakdown in the expected symmetry of shear wave velocities was resolved. It was discovered that a homogeneous anisotropic core in the center of the sample is formed under the standard polyaxial setup where elastic parameters could be computed. Off-diagonal elastic tensor parameters were obtained by a combination of various velocity survey data and justified the ellipsoidal model as being the most appropriate and facilitated the calculation of Thomsen parameters. The ellipsoidal heterogeneous velocity model was also verified by AE event location of transducer shots through the cubic rock specimen especially at the final phase of the experiment consisting lower-velocity zones bearing partially saturated fractures. AE of the rock during the whole experiment recorded by the surrounding transducers were investigated by location methods developed for anisotropic heterogeneous medium. AE events occurred in the vicinity of the dilation pseudo-boundaries where, a relatively large velocity gradient was formed and along parallel fractures in the σ1/σ2 plane. This research facilitated the computation of anisotropic parameters for rock during polyaxial tests contributing to enhanced AE interpretation of fracture growth processes in the rock under laboratory true-triaxial stress conditions.

Keywords: Acoustic Emission Monitoring
Anisotropy
Laboratory Rock Mechanics
Tomography
True Triaxial Test
Advisor: Young, Paul
Seeing Through Rose-colored Glasses? A Within- and Cross-cultural Investigation of Evaluative Bias and Well-being

Cross-cultural research on well-being often focuses on the influence of socio-ecological factors on well-being. National accounts of well-being suggest that modern nations – wealthier, and well-educated nations –are happier than less developed nations. In the current thesis, I examined whether cultural factors influence individuals’ preferences towards self-evaluation, and whether (cross-) cultural differences in positive evaluative bias influence well-being. Given the cultural emphasis on positivity and high self-esteem in North America, I expected European Canadians, compared to Asian Canadians and Asians, to show overly positive biases in ratings of personality and in predictions of their abilities and behaviors. In Study 1, participants were asked to bring a close friend (either a same- or cross-ethnic friend) to the laboratory, and asked to provide self- and informant-ratings of well-being and personality. An improved personality model of positive bias was introduced to disentangle biases from actual personality using self- and informant-ratings of personality. European Canadians compared to Asian Canadians showed higher well-being and higher positive evaluative bias of the self and close other. Importantly, cultural differences in positive evaluative bias mediated cultural differences in self-reported well-being. In Study 2, I used a novel behavioral approach based on signal detection theory to explore positive bias across three cultural groups: European Canadians, Asian Canadians and Koreans. Individuals were asked to bet on their success in ten independent tasks, and then asked to perform the tasks. Comparisons of individuals’ betting behaviors and actual performances served as measures of positive bias. Interestingly, no cross-cultural differences were observed in positive bias in predictions of abilities and behaviors. Taken together, this work highlights the influence of positive bias in well-being ratings, supporting the idea that cultural factors influence individuals’ perception tendencies. Yet, my work suggests that European North Americans are not merely blinded by rose-colored dreams. Cultural norms have less influence on individuals’ self-evaluation depending on the context.

Keywords: culture
evaluative bias
multimethod
personality
positive self-perception
well-being
Advisor: Schimmack, Ulrich
Energy Monitoring and Targeting as Diagnosis: Applying Work Analysis to Adapt a Statistical Change Detection Strategy using Representation Aiding

Energy Monitoring and Targeting is a well-established business process that develops information about utility energy consumption in a business or institution. While M has persisted as a worthwhile energy conservation support activity, it has not been widely adopted. This dissertation explains M challenges in terms of diagnosing and controlling energy consumption, informed by a naturalistic field study of M work. A Cognitive Work Analysis of M identifies structures that diagnosis can search, information flows un-supported in canonical support tools, and opportunities to extend the most popular tool for M Cumulative Sum of Residuals (CUSUM) charts. A design application outlines how CUSUM charts were augmented with a more contemporary statistical change detection strategy, Recursive Parameter Estimates, modified to better suit the M task using Representation Aiding principles. The design was experimentally evaluated in a controlled M synthetic task, and was shown to significantly improve diagnosis performance.

Keywords: cognitive engineering
energy management
experiment
human factors
monitoring and targeting
representation aiding
Advisor: Jamieson, Greg A
Early-adolescent Experiences of Physical Activity: A Sociology of Childhood Approach

Participation in physical activity is the most significant contributor to health and can bring joy, community and psychological well-being. Low rates of physical activity participation are causing national and international alarm. Only 7 per cent of Canadian children and youth receive adequate amounts and intensity of physical activity. Attrition occurs over adolescence, and childhood and adolescent participation influences lifelong participation. Utilizing feminist and sociology of childhood frameworks, this mixed method study explored the physical activity (PA) experiences of 25 middle school students. Findings include that these early adolescents were more active than national averages, that they enjoyed and valued physical activity, that their PA experiences were significantly impacted by their environment, and that they themselves knew what they wanted and what worked for positive participation experiences. School structures, facilities, programming and personnel, the built environment, friends and family were the most significant influences on participation experience. The author concludes that: 1) some populations of young people in some geographic circumstances are more engaged in physical activity and have a more positive attitude than often assumed; 2) researchers, program developers and, most importantly, policy makers concerned with physical activity participation, attrition, and public health must recognize that structures impose sedentaryism, and that individuals’ sense of responsibility for their own health behaviours alone is inadequate in creating an active population; 3) young people have authentic, credible knowledge and their observations, experiences and voice hold key insights to their own sustainable or increased participation in physical activities; and 4) young people need to be listened to and included as participants in the design of the structures that create the social, physical and educational environments in which they learn and live. Recommendations for policy, programming and future research are presented.

Keywords: early-adolescents
education
participation
physical activity
sociology
sociology of childhood
Daily Physical Activity
DPA
Advisor: Acker, Sandra
In-vivo Biomarkers for Detection of Early Diabetic Retinopathy Using Aqueous Humor Cytokines and Functional Retinal Imaging Techniques

Diabetic retinopathy (DR) is the leading cause of blindness in working age adults worldwide. Prior to the onset of clinical DR, alterations in retinal hemodynamics have been reported. However, the underlying pathogenesis for retinal hemodynamic dysfunction remains unknown. Retinal hemodynamic disturbance reflects the complex diabetes-induced pathologic alteration that occurs in the diabetic retina and these pathogenic changes are likely reflected in the aqueous humor (AH). Using multiplex bead analysis, we determined the levels of ET-1, VEGF, Ang-2, FGFs, IL-8, PlGF, TGF-β1 and TGF-β2, which have been proposed to be centrally involved in the progression of DR, in patients with early retinal hemodynamic disturbances. The purpose is to identify important cytokines that are associated with retinal hemodynamic abnormalities and impaired vascular reactivity response during early DR. We compared AH cytokines levels between non-proliferative diabetic retinopathy (NPDR) and control groups. We also evaluated total retinal blood flow (TRBF) using the Fourier Domain Optical Coherence Tomography (FD-OCT). Additionally, we measured retinal vascular reactivity response using the bidirectional laser velocimetry and a standardized isocapnic hyperoxic provocation method. We determined the relationships between AH cytokines, retinal blood flow and vascular reactivity responses in each group. We found significantly increased angiogenic cytokines (ET-1, Ang-2, PlGF, TGF-β1 and TGFβ-2) and reduced FGF-1 levels in the NPDR group compared to the control group. The presence of pro-angiogenic cytokines indicates progression of ischemia, which is consistent with the reduced TRBF observed in the NPDR group compared to the control. Although not directly correlated, the vasoconstrictory effects of ET-1 are also consistent with lower TRBF found in early DR. FGF-1 levels are significantly positively associated with TRBF and VR response in patients NPDR. In the absence of retinal ischemia, we show that early diabetes-induced alterations influences AH composition as well as retinal hemodynamics and arteriolar vascular function, and may be concomitant with respect to their development. Although further work is required to determine the pathogenic mechanism of FGF-1, our study points to the important and novel role of FGF-1 in mediating impairments in TRBF and retinal VR during early DR.

Keywords: Angiogenesis
Biomarkers
Diabetes Type 2
Diabetic Retinopathy
Microvasculature
Retina
Advisor: Hudson, Chris
Prioritizing Climate Action for Low-carbon Growth in Cities

Cities play a vital role in the global economy, which necessitates incremental progress towards low-carbon growth to serve their long-term needs and remain competitive locally and collectively. Urban energy consumption makes the climate challenge more pronounced in cities, where simultaneously, the opportunities for mitigation are prevalent. From a climate governance perspective, this thesis examines the prioritization of climate action to meet greenhouse gas emission targets that come at a cost to cities and their residents. The thesis presents four papers that together structure climate action by developing tools to support cities in decarbonizing their economic growth. A three-pronged approach to climate action is developed to integrate key city documents: Greenhouse Gas Emissions Inventories, Climate Action Plans, and Budgets, and a review of practices and advancements in progressive cities are presented. Greenhouse gas inventories are the starting point of cities’ climate action, which are analyzed comparatively as they apply to community, corporate and upstream emissions, with examples from New York, Shanghai and Paris. Surprisingly not typically linked to inventories, climate action plans are strategic documents defining ambitious initiatives to reduce emissions. A methodology to compile mitigation measures suggested in climate policies and programs in a city, and that of higher orders of government is established, and their cost-effectiveness and abatement potential is calculated and illustrated in the form of a marginal abatement cost (MAC) curve. A case study of prioritizing mitigation measures in the energy supply, buildings, transportation and waste sectors is demonstrated for Toronto’s climate targets, drawing implications for the city’s 2020 and 2050 outlook. To integrate budgets with inventories and action plans, the METRO model is designed for cities to forecast greenhouse gas emissions and evaluate city budgets and business and household incomes relative to climate mitigation priorities. Applying the model to Toronto, the methodology of the METRO model is demonstrated to show that climate commitments have a quantitative dimension and an economic reality. Prioritized climate action positions cities for timely mitigation efforts, where knowledge sharing among cities is paramount to achieving low-carbon growth.

Keywords: budget
climate action plan
greenhouse gas emissions
greenhouse gas inventory
marginal abatement cost
Toronto
Advisor: Kennedy, Christopher