VictorJuiz/thesis huggingface dataset:
Modeling Hedge Fund Performance Using Neural Network Models
Keywords: Neural Networks
Hedge Funds

Hedge fund performance is modeled from publically available data using feed-forward neural networks trained using a resilient backpropagation algorithm. The neural network’s performance is then compared with linear regression models. Additionally, a stepwise factor regression approach is introduced to reduce the number of inputs supplied to the models in order to increase precision. Three main conclusions are drawn: (1) neural networks effectively model hedge fund returns, illustrating the strong non-linear relationships between the economic risk factors and hedge fund performance, (2) while the group of 25risk factors we draw variables from are used to explain hedge fund performance, the best model performance is achieved using different subsets of the 25 risk factors, and, (3) out-of-sample model performance degrades across the time during the recent (and still on-going) financial crisis compared to less volatile time periods, indicating the models’ inability to predict severely volatile economic scenarios such as economic crises.
The Nucleus of the Solitary Tract is Necessary for Apnea-induced Respiratory Plasticity
Keywords: respiratory plasticity
long term facilitation

The respiratory system is attentive, adaptive, learns and has memory. The respiratory system remembers repeated respiratory challenges to fine tune its motor activity by modulating neuronal synaptic strength. This phenomenon, respiratory long term facilitation (LTF), functions to strengthen the ability of respiratory motor neurons to enhance contraction of breathing muscles. LTF could serve as a protective mechanism against obstructive sleep apnea, a disease characterized by the collapse of upper airways, by restoring upper airway patency. LTF can be induced through modulation of vagal afferent feedback via repeated apneas. Here, we used reverse microdialysis, electrophysiology, neuropharmacology, and histology to determine if the nucleus of the solitary tract (NTS), a brain region exclusively receiving vagal afferents, is the origin of the neural circuit responsible for apnea-induced plasticity. My work shows bilateral injection of 5% lidocaine into the NTS prevented LTF. We conclude the NTS is required for triggering apnea-induced LTF.
The Role of Oxidative Stress on Neural TRPC3, TRPC5, TRPC6 Expression and/or Function and Relevance to Bipolar Disorder
Keywords: Bipolar Disorder
Oxidative Stress
TRP Channels
Calcium

The etiology of bipolar disorder (BD) is multidimensional and thought to involve several factors that increase neuronal oxidative stress and disrupt intracellular calcium homeostasis. As calcium-permeable canonical transient receptor potential channels (TRPC) have been linked to bipolar pathophysiology, I sought to determine whether oxidative stress affects TRPC3/TRPC5/TRPC6 expression and/or function. Chronic (4-day) but not acute (24-hour) rotenone-induced oxidative stress dose-dependently reduced TRPC5 and TRPC6 protein levels in primary rat cortical neurons. A decrease in TRPC5 mRNA levels was only found following acute but not chronic rotenone whereas TRPC6 mRNA levels did not change significantly with either treatment. Reduced TRPC3 function was seen after chronic stress when stimulated by TRPC3/6 activator, 1-oleoyl-2-acetyl-sn-glycerol. Lithium pre-treatment attenuated the rotenone-induced reduction in TRPC3 but not TRPC6 protein levels. These results suggest TRPC subtypes are differentially regulated by oxidative stress and support a potential mechanistic link between oxidative stress and calcium dyshomeostasis in BD.
Engineering the Myocardial Niche in a Microscale Self-assembling Tissue-mimetic in vitro Model
Keywords: In vitro 3D cardiac model
human pluripotent stem cell-derived cardiomyocytes
Maturation of cardiomyocytes
Microfabrication for cell-based assays

Drug- and cell-based strategies for treating heart disease, including myocardial infarction, face significant roadblocks on the path to the clinic, a primary obstacle being the lack of information-rich in vitro human model systems. Conventional model systems are hampered by at least one of three fundamental limitations which include a) the lack of an in vivo-like microenvironment specifically engineered for the input cell population, b) a relatively low-throughput assays, and c) the low-content nature of output parameters. We describe an integrated computational, design, and experimental strategy for the rational design of a microfabricated high-content screening platform which we term the Cardiac MicroWire (CMW) system. Within this system, we recapitulate the basic microenvironment found in the heart, one which integrates cardiomyocytes, non-myocytes, the extracellular matrix, and dynamic electromechanical forces. Our results highlight the CMW system’s potential as a powerful discovery tool for screening small molecules and transplantable cells toward heart regeneration therapies.
Achieving Low Emissions from a Biogas Fuelled SI Engine Using a Catalytic Converter
Keywords: Biogas
SI engine
Catalytic Converter
Three-way Catalyst
Natural Gas

A spark ignition engine was retrofitted to operate on biogas fuel. Biogas was synthetically generated through the mixing of various pure gases. The air-fuel ratio was accurately controlled using a closed feedback system consisting of flow controllers and a wide range oxygen sensor. A natural gas catalytic converter was implemented with the use of biogas fuel. To achieve full NOx and CO reduction the engine was required to run at a slightly rich equivalence ratio. Methane emissions posed to be the hardest to reduce across the catalyst. The biogas fuel composition had no effect on the catalyst performance. The catalyst performance was only affected by exhaust temperature and equivalence ratio. The catalyst requires tight A/F ratio control for optimal performance. A Catalytic converter can be used to reach low emissions but requires the knowledge of the biogas fuel composition.
Realistic Assessment of Novel Wireless Systems with Ray-tracing Based Techniques
Keywords: Ray-Tracing
Wireless Channel Modeling
Ultra-wideband Systems
MIMO

Ray tracing based on geometric optics can be utilized for generating propagation models for arbitrary and complex environments. These methods can be employed to determine important wireless channel characteristics such as path gain and the channel impulse response which in turn can be used to deduce channel capacity. In this thesis, a fully vectorial 3-D ray-tracer is developed. The simulator is applied to study novel wireless systems such as ultra-wideband pulse propagation in complex railway tunnels and MIMO systems employing closely spaced low mutual coupling meta-material antennas. The computational complexity of the ray-tracing algorithm is reduced using optimizations and via the development of a novel hybrid method that combines the efficiency and accuracy of waveguide models with the flexibility of a ray-tracer. The resulting simulator is validated against measured results and demonstrated to show good agreement. Convergence of the solution using the ray-tracing method is also discussed.
Level of Automation Effects on Situation Awareness and Functional Specificity in Automation Reliance
Keywords: Automation
Supervisory control
Level of automation
Situation awareness
Signal detection theory
Task analysis
Reliance
Trust
Human Factors

This thesis investigates the relationships between performance, workload, and situation awareness at varying levels of automation. The relationships observed in this study are compared to a description put forth to formalize the conventional interpretation of the trade-off between the benefits of automation during routine operation and the costs under conditions of automation failure. The original work stipulated that this “routine-failure trade-off” is likely a simplification affected by contextual factors. This work therefore aimed to i) provide empirical evidence to support or refute the trade-off and ii) to identify possible extenuating factors. The results generally supported the routine-failure trade-off, and considered in light of the functional structure of the task suggested that the relationships between goals and individual functions specific to a given task seem to affect the overall costs and benefits of automation through the mechanism of selective reliance. Further work is required to validate the findings of this study.
Impact of Comorbid Major Depressive Disorder (MDD) on PTSD Severity in Toronto Transit Commission (TTC) Employees
Keywords: Psychological trauma, Posttraumatic Stress Disorder, MDD, Comorbidity, Mental health, TTC

Introduction: This thesis examined the impact of PTSD with Major Depressive Disorder on PTSD severity among Toronto Transit Commission employees who were exposed to a workplace traumatic event, and also the predictors of PTSD severity, mental health treatment seeking, and return to work over the six month study period. Methods: This study utilized data that was collected prospectively from the APT study participants. Information about Axis-I diagnosis and PTSD severity were collected from the SCID-I and the Modified PTSD Symptom Scale respectively. Results: PTSD without MDD (N=29) and PTSD with MDD (N=37) groups were compared. The variables: depression severity (p=0.01), female (p=0.01), non-Caucasian (p=0.01), workplace related stress (p=0.02), and lifetime trauma (p=0.01) significantly predicted PTSD severity. The BPI group significantly predicted mental health treatment seeking (p<0.01) after controlling other variables. Conclusion: This study highlights the substantial risk for experiencing greater PTSD severity after a workplace traumatic event in TTC employees.
Modelling Departure Time and Mode Choice for Commuting in the Greater Toronto and Hamilton Area (GTHA): Evaluation of Dynamic Travel Demand Management Policies
Keywords: transportation
travel behaviour modelling

This thesis develops econometric models of departure time and travel mode choice to evaluate dynamic transportation policies. Dynamic policies affect travel attributes differently throughout the day. Both departure time and mode choice are modelled with Random Utility Maximizing (RUM) Generalized Extreme Value (GEV) discrete choice models that capture systematic and random heterogeneity. Departure time is represented by a heteroskedastic generalized extreme value model (Het-GEV) with overlapping choice sets. Studying the Greater Toronto and Hamilton Area (GTHA), models are estimated using Revealed Preference (RP) household travel data from the 2006 Transportation Tomorrow Survey (TTS). Empirical models are used to evaluate dynamic transit and road pricing policies. Results indicate that the models are capable of capturing mode and time switching behaviour in response to peak pricing policies. To alleviate demand while maintaining transit mode share, a road charge and a moderate, flat, transit fare increase throughout the morning peak are recommended.
A Microfluidic Platform for the Investigation of Transport in Small Blood Vessels
Keywords: permeability
microvasculature
microfluidics
FITC-Dextran
artery-on-a-chip

The microvasculature has the main function of transport of dissolved gases, nutrients and waste between blood and tissue. Systematically probing transvascular transport rates in these vessels under well defined conditions is challenging. In vivo and in vitro studies are characterized, respectively, by limited optical access and control over perfusion concentrations and failure to resemble the structure and function of an intact organ. In this thesis, I present the development of a microfluidic platform for investigating molecular transport across mouse mesenteric arteries (150-300μm diameter) in a controlled physico-chemical microenvironment. Intact vessels are perfused with 4 kDa FITC-Dextran and the permeation coefficient of this molecule across the vessel wall is quantified using laser scanning confocal microscopy paired with a 2-D numerical model. Functional viability of the examined vessel, through phenylephrine and acetylcholine dose responses, is probed, and shear and phototoxic effects are reported.
Fluorescence Resonance Energy Transfer between a Monolayer of Quantum Dots as Donors adjacent to a Monolayer of Biorecognition Elements as Acceptors
Keywords: quantum dots
fluorescence
hybridization
immobilization

The unique optical properties of quantum dots (QDs) have been widely used to develop bioassays based on Fluorescence Resonance Energy Transfer (FRET). The solid-phase assays using QDs as FRET donors have numerous practical advantages, including at least 10-fold enhancement in FRET efficiency, which is not immediately explained by theoretical predictions that model energy transfer processes of QDs in two-dimensional layers. Donor-acceptor separation distance, acceptor and donor concentrations were found to influence FRET efficiency in solid-phase assays. A novel immobilization strategy was implemented which made use of the high affinity of imidazole moieties to QD shells to build solid-phase QD bioassays. A 96-well polystyrene plate is presented as a platform suitable for rapid and convenient multiplexed detection. A typical microtiter plate reader was shown to be capable of discriminating different FRET pairs to picomol detection levels of target oligonucleotides. Furthermore, the QD-FRET bioassays provided for mismatch discrimination, and multiple cycles of regeneration were also demonstrated.
Patients’ Preferences and Trade Offs for the Treatment of Small Hepatocellular Carcinomas
Keywords: Hepatocellular Carcinoma
Radiofrequency Ablation
Hepatic Resection
Cirrhosis
Patient's Preferences
Perioperative Risks
Treatment Benefits
Probabiltity Trade-off

Objective: The primary aim of this study was to assess patients’ preferences between radiofrequency ablation (RFA) versus hepatic resection (HR) for the treatment of small hepatocellular carcinomas (HCC). Methods: Decision analysis was performed by using probability trade-off (PTO) technique to elicit patients’ preferences and the strength of their decisions. Results: The vast majority of the study population preferred RFA over HR (70% vs. 30%, p=0.001). Their initial choice changed if 5-year survival benefit after surgery was at least 14% superior to RFA and if the 3-year disease-free survival advantage was at least 13% better than ablation. Conclusions: The results of this study suggest that fully informed cirrhotic patients would prefer RFA if diagnosed with early stage HCC even if able to undergo surgery.
Adaptive and Robust Radiation Therapy Optimization for Lung Cancer
Keywords: robust optimization
adaptive radiation therapy
intensity-modulated radiation therapy

A previous approach to robust intensity-modulated radiation therapy (IMRT) treatment planning for moving tumours in the lung involves solving a single planning problem before treatment and using the resulting solution in all of the subsequent treatment sessions. In this thesis, we develop two adaptive robust IMRT optimization approaches for lung cancer, which involve using information gathered in prior treatment sessions to guide the reoptimization of the treatment for the next session. The first method is based on updating an estimate of the uncertain effect, while the second is based on additionally updating the dose requirements to account for prior errors in dose. We present computational results using real patient data for both methods and an asymptotic analysis for the first method. Through these results, we show that both methods lead to improvements in the final dose distribution over the traditional robust approach, but differ greatly in their daily dose performance.
Examining the Nature of Epistasis between wupA and for Incomplete Dominance at wupA and epistatic Interactions with for Alleles give Rise to a Gradient Effect in Foraging Behaviour
Keywords: Foraging behaviour
Drosophila Melanogaster
wings up A gene
foraging gene
Incomplete dominance
PKG
Troponin I

Foraging behaviour in Drosophila melanogaster larvae is influenced by natural allelic variation in the foraging (for) gene that encodes a cyclic GMP – dependent protein Kinase (PKG), such that rovers (forR) traverse greater distances while foraging than sitters (fors). Foraging behaviour is also influenced by natural allelic variation in the wings up A (wupA) gene that encodes the Troponin-I protein (TnI). Specifically, wupAlow allele suppresses the dominance of the forR allele, turning rovers into sitters. The dominance of the natural wupA alleles and their interactions with allelic combinations in for has not been characterized. I conducted various crosses and found that wupA alleles exhibit incomplete dominance. More importantly, I found that allelic combinations of wupA and for gave rise to a range in larval foraging behaviour. In this study, I propose that this gradient effect in foraging behaviour is due to variation in levels of PKG activity and TnI phosphorylation potential.
Desulphurization of Ferronickel Alloy using a Waste Material from Alumina Production
Keywords: desulphurization
ferronickel
red mud
recycling
sustainability
refractory materials

Red mud is a waste product of alumina production and has an adverse effect on environment. About 90 million tonnes of red mud are produced annually throughout the world and little is recycled for useful applications. The world nickel reserves consist of approximately 30% sulphide ores and 70% oxide ores. Despite the relative abundance of oxide ores, 55% of nickel and nickel alloys produced today are derived from sulphide ores. However, with the production of nickel and its alloys from low-grade oxide ores becoming increasingly important, a major concern is high sulphur level in the resultant alloy. For this reason, desulphurization of the ferronickel becomes an important consideration. In the present study, experiments were conducted to determine if red mud could be used as a major ingredient of custom designed fluxes for the desulphurization of ferronickel alloy. Factors investigated included desulphurization rates, contact angle measurements and flux-refractory interactions.
Reliability Models for Linear Assets
Keywords: Reliability
Maintenance
Reliability Modelling
Linear Assets
Pipelines
Survival Analysis

Linear assets are among the largest and most important engineered systems; their reliability is of the utmost importance. This thesis presents an overview of the reliability estimation methods used for the various types of linear assets, both observation- and statistically-based. While observation-based reliability monitoring and estimation methods are necessarily particular to a certain type of asset, statistically-based methods developed for one type can potentially inform those used for another. Therefore, this thesis looks to point out commonalities in the methods for the statistical evaluation of the reliability of various types of linear assets, develop and extend reliability models and methods with this knowledge, and suggest how maintenance strategies may be improved. To help illustrate and test the models described in this paper a case study was conducted with a utility operator; this thesis shows the modelling results from the study, and demonstrates the model’s use in a maintenance decision model.
Performance of Support Systems Subjected to Dynamic Loads at Two Underground Nickel Mines
Keywords: Vale
Support System Performance
Dynamic Loading
Coleman Mine
Copper Cliff Mine
Mining
Underground Support

The consequences of mine seismicity can be mitigated by installing support systems capable of absorbing the energy generated by seismic events. Recent work has focused on the testing of individual support or reinforcement units under laboratory impact loads; this, however, does not render itself to easy extrapolation to field conditions. Hence, this thesis focuses on improving the understanding of the performance of support systems in real-world applications through passive monitoring of past rockburst events. 14 years of rockburst history were collected from Coleman Mine and Copper Cliff Mine, two of Vale’s underground (nickel) operations in Sudbury Ontario. Statistical analysis, principal component analysis (PCA) and partial least square projection (PLS) were utilized to find relation between collected parameters and performance capacity. This thesis discusses the adequacy of various support systems and investigates the validity of perceived support performance as compared to the actual performance based on analyses of field data.
Development of a Slab-on-Girder Wood-concrete Composite Highway Bridge
Keywords: bridge
composite
wood
concrete
wood-concrete composites
composite bridges
slab-on-girder bridges
post-tensioned bridges
ultra-high performance fibre-reinforced concrete
glued-laminated timber
glulam
highway bridge
WCC
TCC
timber-concrete composites
advanced materials
short span bridges
unbonded post-tensioning
external post-tensioning
double-T
match-casting
bridge design
bridge engineering
laminated wood

This thesis examines the development of a superstructure for a slab-on-girder wood-concrete composite highway bridge. Wood-concrete composite bridges have existed since the 1930's. Historically, they have been limited to spans of less than 10 m. Renewed research interest over the past two decades has shown great potential for longer span capabilities. Through composite action and suitable detailing, improvements in strength, stiffness, and durability can be achieved versus conventional wood bridges. The bridge makes use of a slender ultra-high performance fibre-reinforced concrete (UHPFRC) deck made partially-composite in longitudinal bending with glued-laminated wood girders. Longitudinal external unbonded post-tensioning is utilized to increase span capabilities. Prefabrication using double-T modules minimizes the need for cast-in-place concrete on-site. Durability is realized through the highly impermeable deck slab that protects the girders from moisture. Results show that the system can span up to 30 m while achieving span-to-depth ratios equivalent or better than competing slab-on-girder bridges.
The Info-immersive Modalities of Film Documentarian and Inventor Roman Kroitor
Keywords: Roman Kroitor
Immersion
Expanded Cinema
IMAX
National Film Board
Stereoscopy
Animation
Canada

In this thesis, it is argued that Canadian film documentarian and inventor Roman Kroitor’s lifework is structured by simultaneous appeals to the realist and reflexive capacities of film and animation. It is shown that the diverse periods in Kroitor’s lifework (including documentary film production at the National Film Board of Canada; co-invention and development of the large-format film apparatus, IMAX; and software design for computer animation in stereoscopic 3D) are united by a general interest in facilitating immersive audience experiences with documentary information and evidentiary entertainment. Against those who have conceptualized cinema as functioning like a frame or a window, this thesis analyzes Kroitor’s diverse work in relation to Gene Youngblood’s conception of “expanded cinema” (1970). It is argued that Kroitor’s efforts in film and invention constitute modalities that actively eschew the architectonic limits that typically characterize the cinematic experience.