VictorJuiz/thesis huggingface dataset:
Topology Optimization Studies for Light Weight Acoustic Panels
Keywords: acoustic
bandgap
optimization
panel
sandwich
topology

With the growing need to reduce green house gas emissions, increasing flight effciency has been a primary challenge faced by the aviation industry. Designing lighter and more effcient aircraft is becoming a goal shared throughout the global air transportation industry. A light weight acoustic panel is desired to replace heavy and bulky foam panels inside the fuselage for cabin noise control. Currently, there is no consensus on the best panel design. Therefore, this thesis will explore using topology optimization to suggest new panel designs. This thesis contains studies of some acoustic panel designs as well as methodologies used to optimize the core topology of a sandwich panel with a maximized band gap while remaining light and stiff. In this thesis, the sound transmission loss has been related to the existence of band gap, and a band gap is being maximized as a surrogate for sound transmission loss. The main results obtained from this thesis show interesting topologies with a band gap around 300 Hz being maximized under mass and stiffness constraints, and the core topologies have been found to have resemblance to resonators.
Motion Control of a Gymnastics Robot Using Virtual Holonomic Constraints
Keywords: gymnastics robot
motion control
robot locomotion
virtual holonomic constraint

In this thesis the motion control problem of a gymnastics robot performing a bar routine is analysed, and a comprehensive solution is developed using the framework of virtual holonomic constraints. The routine is a combination of swinging manoeuvres on the bar and a back-ďŹ ipping dismount in the air. Virtual holonomic constraints are used extensively to parametrize the motions, for which stabilizing controllers are developed. Using tools such as high-gain observers, PoincarÂ´e analysis, and linearization about a trajectory, the virtual constraints are dynamically reshaped so as to meet the control objectives for each motion. A physical gymnastics robot was built in the lab, and experiments were conducted to verify the theoretical predictions. Results show that the solutions developed were robust to real-world imperfections.
Effects of the Lyme Disease Pathogen Borrelia burgdorferi on Murine Bone Biology
Keywords: Bone biology
Lyme disease
Mouse models
Osteopenia

This thesis reports the effects of infection by the Lyme disease pathogen Borrelia burgdorferi on bone biology in mice. Bone mineral density, microarchitecture, and cellular morphology were analyzed. B. burgdorferi was found to directly invade bone. Infection induced osteopenia in long bones but not vertebraes. Trabecular bone was deteriorated by infection, but cortical bone was unaffected. Bone loss was not due to increases in osteoclastogenesis or bone resorption. Instead, it was associated with reduction in osteoblast numbers. Osteoid-producing and mineralization activities of existing osteoblasts were unaffected by infection. This suggested that osteopenia and disruption of trabecular bone in response to B. burgdorferi infection was likely caused by mechanisms which impaired osteoblastogenesis and/or induced osteoblast cell death. Together, these data represent the first evidence that B. burgdorferi infection can induce bone loss, and suggest that this phenotype is due to the effects of infection on osteoblastogenesis and/or osteoblast survival.
Gaming to Safety: The Design and Evaluation of Feedback Gamification for Mitigating Driver Distraction
Keywords: Driver distraction
Driver feedback
Gamification
Intrinsic motivation

This thesis examined the gamification of feedback systems for potential benefits in mitigating driver distraction and enhancing driving performance. Distraction is detrimental to traffic safety. Integrating driver feedback with elements of game design could effectively reduce distraction and motivate lasting behavioral changes. A simulator study was conducted with younger drivers (n = 42) comparing no feedback, a real-time feedback system, a post-drive feedback system (real-time feedback + post-drive feedback), and a gamification feedback system (real-time feedback + post-drive feedback + game design elements). No differences were observed between no feedback and the real-time feedback system. Comparing the gamification and post-drive feedback systems, the gamification system provided more benefits in the rate of manual interactions with an in-vehicle display and the post-drive system provided more benefits in the 95th percentile glance duration to the in-vehicle display. Despite these differences, both gamification and post-drive feedback systems were effective, short term countermeasures of distracted driving.
Mechanistic Modelling in Support of Human Biomonitoring
Keywords: Bioaccumulation
Biomonitoring
Exposure Modelling
Persistent organic pollutants
Polychlorinated Biphenyls

Lifetime exposures to polychlorinated biphenyls (PCBs) were calculated using a combined mechanistic model of environmental fate (BETR-Global) and human food chain bioaccumulation (ACC-Human) for 6128 participants of the United States National Health and Nutrition Examination Survey (NHANES) 1999-2004. Important questionnaire information from NHANES (year of birth, diet, body mass index (BMI), sex, reproductive behaviour) were used as model input. The model performed well on a popula- tion level, where the geometric mean modelled concentration of 13.3 ng/g lipid is close to the geometric mean measured concentration of 22.0 ng/g lipid. While the model successfully reproduced measured trends with age, sex, BMI, a failure was observed with diet. Furthermore, the model was used to explore the relationship between PCB levels and BMI, and it was found that these relationships depend on i) age, ii) the time of sampling, and iii) the range of body mass index sampled.
Driving Performance and Underlying Brain Activation Patterns in Chronic Stroke Patients
Keywords: Driving
fMRI
Ischemic Stroke
Stroke
Subarachnoid Hemorrhage

Resuming driving is an important priority for many stroke patients, yet persistent deficits may result in impaired driving performance. The present study used driving simulation and functional magnetic resonance imaging to examine whether stroke patients exhibit behavioural impairments and differences in brain activation patterns during driving tasks of varying complexity. Stroke patients committed more hazardous errors and errors at intersections, specifically when making complex left turns at intersections with oncoming traffic. Patients exhibited deviations from expected neural activation patterns during the most complex driving maneuver. The results of the present study suggest that stroke patients exhibit impairment during complex aspects of driving, specifically during intersections, and display altered patterns of neural activation as the perceptual and cognitive demands of the driving task increase. Further research is required to develop and validate existing screening measures and rehabilitation programs that target these specific driving impairments observed in functionally independent, chronic stroke patients.
Sex in Space! Does Sexual Selection Accelerate or Hinder Adaptation?
Keywords: Adaptation
Drosophila
Evolutionary Ecology
Good Genes
Sexual Conflict
Sexual Selection

Theory suggests sexual selection should accelerate adaptation in novel environments. A number of past studies used Drosophila species to test this prediction, and yielded inconsistent result. However, these experiments were all conducted in settings where the test populations are being housed in spatially restricted, simple mating environments. The use of high-density, small and physically simple arenas can exacerbate the effect of male harassment, which reduces both selection on high condition females, and selection against low condition males. Adult fly interaction in large and complex mating environment is predicted to alter selection by alleviate the intensity of male harassment, and increase selection on males. As a necessary extension to past studies, we give evidence suggesting that sexually selected populations evolving under complex ecological environment yields fitness measure more consistent with the alignment of natural and sexual selection.
Completing the Feedback Loop: An Assessment of the Implementation of an Early Stage Audit and Feedback Intervention in Primary Care
Keywords: Audit and Feedback
Primary Care

Audit and Feedback (A) is a common quality improvement strategy characterized as an feedback loop enabling an iterative, self-regulating progress. The objective of this thesis was to evaluate the implementation of a specific A program in team-based primary care practices. Eighteen semi-structured interviews were conducted to explore its implementation and factors influencing participation. Interview transcripts were analyzed deductively with the support of the Consolidated Framework for Implementation Research. Findings revealed that implementation was not representative of a complete feedback loop. Participation was primarily associated with a perception that the program would develop into a best-in-class A initiative for primary care. The relationship between physicians and organizational administrators was identified as a key factor which may support or deter implementation. The study also identified factors related to the design and delivery of A that may explain why and how an A intervention in primary care can achieve its objectives.
Exploring the Feasibility of Prompting Daily Task Execution using the NAO Humanoid Robot with Children with Autism Spectrum Disorder
Keywords: asd
assistive technology
autism
hand washing
prompt
robotics

This thesis seeks to improve the state of the art prompting system, COACH, for the children with ASD population. It investigates the feasibility of using a humanoid robot, NAO, as its prompting agent through a Wizard of Oz (WoZ) pilot study. The WoZ study showed promising results of the robot potentially being used as an assistance to a child with ASD through hand-washing tasks. The study also suggested parent robot joint prompting sessions as a valid method for improving child's compliance to the robot. The important challenges faced are summarized and possible recommendations for overcoming these challenges are suggested.
Inflammatory Cell Responses to Vascular Regenerative Methacrylic Acid-containing Materials
Keywords: complement activation
host response
macrophage polarization
methacrylic acid

Poly(methacrylic acid-co-methyl methacrylate) (MAA) beads improve vascularization when applied to cutaneously-wounded diabetic mice. The aim of this thesis is to understand the vascular regenerative properties of MAA at the cellular and molecular level. Subcutaneous injection of MAA beads promoted the formation of a denser and perfusable network of blood vessels at days 3 and 7 relative to poly(methyl methacrylate) (MM) control beads. MAA beads modulated the host response; promoting more neutrophils at day 1 and more macrophages at day 7, relative to MM beads. A M2 macrophage polarization bias was observed in MAA-treated animals but not in MM-treated animals. Additionally, complement was involved in the mechanism of MAA; complement inhibition (at the C1 or C3 levels) diminished the M2 polarization bias at day 3, although no changes in vascularity were noted. These findings deepen our understanding of MAA and benefit the development of MAA-based biomaterials for applications in regenerative medicine.
Analysis of Hybrid MD-MPC Simulations of Micelle Formation under Neutral pH and Dynamics under Acidic pH Using Different pH-Sensitive Triblock Copolymer Structures
Keywords: drug delivery
Micelle
Molecular Dynamics
Multiparticle Collision Dynamics
pH-sensitive
polymer

The solubilization of hydrophobic drug molecules in the bloodstream by micelles is a promising method for drug delivery to cancerous cells. Cancerous cells and their surrounding environment can be distinguished easily from healthy cells by their pH: acidic vs neutral respectively. This has led to the design of pH-sensitive micelles that are triggered by cancerous cells. When designing the drug or amphiphilic polymer, the drug loading and release rates are quantities that should be optimized for effective delivery. To better understand the factors affecting these quantities, pH-sensitive micelle dynamics in an acidic environment is studied computationally with molecular dynamics simulations (not experimentally due to constraints in time and length scales). By treating the solvent-solvent interactions implicitly through multiparticle collision dynamics, a coarse-grain model of polymers, drugs, and solvent is used to examine drug distribution and micelle dynamics in an acidic environment for different amphiphilic triblock copolymer structures.
Performance and Evaluation of Quality Indicators in the Management of Patients with Heart Failure
Keywords: HEART FAILURE
KNOWLEDGE TRANSLATION
MEDICAL GUIDELINES
QUALITY INDICATORS
QUALITY OF LIFE

The systematic evaluation of evidence-based quality indicators (QIs) in patients with heart failure (HF) is important to assess the quality of care provided to these patients. Guideline recommended therapies have proven to reduce clinical event rates, however quality of life (QoL) is frequently missed as an endpoint in the measurement of treatment efficacy. We hypothesized that there was high adherence to the Canadian Cardiovascular Society (CCS) outpatient QIs, and the adherence was positively associated with QoL. We evaluated the performance of the outpatient QIs extracted from the CCS recommendations and examined their relationship with patient-reported QoL, measured by the Minnesota Living with Heart Failure Questionnaire (MLHFQ) and the Kansas City Cardiomyopathy Questionnaire (KCCQ). We found that there was high adherence (89%) to evidence-based QIs and patients reported a clinically significant improvement in QoL (>5 points), however, there appears to be no association between the performance of these indicators and patient-reported QoL.
A Security Platform Using Software Defined Infrastructure
Keywords: Autoscaling
Cloud Computing
Intrusion Detection System
Load Balancing
Network Security
Service Chaining

In this work, we designed an architecture for cloud network security, leveraging Software Defined Infrastructure, which enables centralized management of compute and networking resources. We show that utilizing SDIâ s service chaining and its Software Defined Networking approach, network security functions such as intrusion detection and prevention, as well as distributed firewalls can be realized as services in the cloud, as modeled in Network Function Virtualization. In our platform, protective resources are located as close as possible to the entity being protected. Furthermore, the design of the user-friendly interfaces for these services to be used is discussed, where the user traffic flows are associated with Enhanced Security Profiles, together forming Enhanced Security Groups. We also discuss our implemented proof-of-concept on SAVI testbed.
Decentralized Scheduling and Control in Power Systems
Keywords: DC-segmented systems
Decentralized control
Dynamics programming
Energy storages
Poset-causal

Decentralized control reduces the need for expensive and delay inducing communication infrastructure. In this thesis we will present new algorithms for decentralized control of DC-segmented power systems and energy storages. DC-segmentation is a process in which a transmission system is divided into isolated AC subsystems connected to each other only by DC lines. It improves transient stability and increases the transmission capacity of a transmission system. We construct a poset-causal optimal decentralized controller for this system, which only requires neighbor-to-neighbor communication. In the second part of this thesis, we focus on multiple energy storages located in a distribution system with renewable generation. We use dynamic programming and inventory control theory to obtain optimal scheduling policies for the energy transactions of the storages. These policies are optimal and only require local information.
Development of a Tissue Oxygen Saturation Detection System for Improving Surgical Training
Keywords: surgical training
tissue damage prevention
tissue oxygen sensor

Delicate tissue encountered in surgery is prone to ischemic damage from grasping and retracting especially by novice surgeons. Currently, there are no existing techniques to quantitatively assess tissue health during surgical maneuver. A transmission and reflectance mode tissue oxygenation (StO2) sensor was developed and integrated into a standard laparoscopic tool and custom forceps to continuously measure tissue oxygenation during surgery. Numerous wavelengths including 470nm, 500nm, 510nm, 560nm, 570nm, 586nm, 660nm and 940nm were tested in reflection mode while 660nm and 940nm were tested in transmission mode. StO2 sensor successfully detected oxygenation changes on the finger and during ex vivo experiment conducted on arterial and venous blood samples. StO2 sensor was unable to monitor changes when grasping small intestine and liver using surgical instruments. Various factors including lack of hemoglobin at the site of measurement, tissue thickness changes during grasps, and motion artifacts limited the use of this technology.
Development of a Decision Aid for Evidence-informed Public Health Policy: A Mixed Methods Study
Keywords: decision aid
evidence-informed
health policy

This study contributes to the evolving needs of decision support for evidence-informed health policymaking. Its aim was to bring more formal consideration of context and a broader conception of evidence into public health policymaking, giving due prominence to all relevant types of evidence. A sequential mixed methods approach was used to undertake the development of a decision aid to support evidence-informed public health policy. A meta-narrative review and focus group were conducted to inform the initial development of the proposed aid. Key informant interviews followed, providing preliminary feedback for refinement of the tool. The final deliverable was a beta-version of a decision aid designed to assist policymakers with making evidence-informed public health policy decisions, ready for pilot testing and further development.
Genetic Variation and Early-life Nutritional Stress Interact to Affect Adult Excretion and Fitness Traits
Keywords: Ecology
Evolution
Life history
Nutritional stress

Life-history strategies are complex and separable into distinct stages, where early experience can affect adult life. In addition, gene-by-environment interactions or individual genetic differences interacting with the environment can influence phenotypes within and between life history stages. Here, using Drosophila melanogaster, I show rover/sitter allelic variants of the foraging gene (for) interact differently with their early nutritional environment affecting adult excreta deposit number, intestinal physiology, and fitness traits and that excretion phenotypes are mediated by differences in for expression. I found rover/sitter differences in intestinal and reproductive physiology that suggest trade-offs between adult gut function and reproductive output. Using transgenic manipulations, I demonstrated that reducing for expression in an organ and tissue specific mannerâ including the gastric systemâ affects phenotypic differences in adult excretion. My findings highlight the importance of investigating individual genetic differences in the context of early environmental experience to fully understand organismal biology and phenotypic complexity.
Optimal Conditions for the Monocyte Monolayer Assay and Applications of the Assay
Keywords: Fc gamma receptor
Hemolysis
Monocyte monolayer assay
Red blood cells
Storage
Transfusion

Immune-mediated hemolysis, whether due to transfusion of incompatible red blood cells (RBCs) in hemolytic transfusion reactions or passive transfer of anti-RBC antibodies through intravenous immunoglobulin (IVIG) therapy, contributes to complications and comorbidities in patients. A major mechanism of RBC destruction is Fc gamma receptor (FcÎłR)-dependent phagocytic removal of antibody-bound RBCs by monocyte-macrophage within the mononuclear phagocyte system. The monocyte monolayer assay (MMA) assesses FcÎłR-mediated destruction using primary monocytes from whole blood and predicts in vivo survival of serologically incompatible, allogeneic RBCs. Optimal conditions for MMA were examined in this thesis. Whole blood collected in acid citrate dextrose anticoagulant and stored at room temperature for up to 36 hours best preserved monocyte phagocytic function. Such conditions were validated using clinical samples from patients receiving IVIG. The findings suggest stored autologous patient samples yield clinically relevant MMA results, and thus permit the shipping and testing of properly stored samples.
Robotic Path-finding in Inverse Treatment Planning with Continuous Dose Delivery for Stereotactic Radiosurgery
Keywords: Gamma Knife Perfexion
heuristic methods
inverse planning
radiosurgery
simultaneous localization and mapping

Continuous dose delivery, or continuous path (CP) treatment, in stereotactic radiosurgery has been proven to improve the total treatment time, dose conformity, and dose distribution homogeneity over traditional step-and-shoot delivery. We develop several automated planning methods using robotic path-finding techniques to design CP treatments for SRS with Gamma Knife Perfexion. Using simultaneous localization and mapping (SLAM), we construct paths through the target that pass sufficiently close to a set of pre-selected isocentre locations. To solve SLAM, both the traditional extended Kalman filter (EKF) and incremental smoothing and mapping (iSAM) algorithms are investigated. Steering decision algorithms using heuristic scoring methods and robotic exploration techniques, specifically, frontiers, are investigated. Once a path is found, shot delivery from each sector is optimized along the path using inverse planning optimization. The SLAM methods consistently improve dose metrics and beam-on time compared to the clinical and an earlier graph-based Hamiltonian path CP planning approach.
Extraction of Rare Earth Elements from Phosphogypsum (Fertilizer Production By-product)
Keywords: Acid leaching process
Chemical modelling
Kinetics investigations
Lanthanides
Phosphogypsum
Rare earth elements

The increasing demand for rare earth elements (REEs), used in technologically advanced products, has sparked the development of novel processes to recover REEs from secondary sources. Phosphogypsum (PG), the main by-product of fertilizer production contains some REEs, so it can be used as a secondary source. The current research focuses on: a thorough characterization analysis; acid leaching process; kinetics of the leaching process; recycling of consumed acid and effect of microwave pre-treatment on the REEs leaching. The results show that the leaching efficiency is controlled by the solubility limit of PG. Systematic leaching experiments using three acids under various operating conditions were performed. The results indicate the best operating conditions are 1.5 M, 80째C, solid-to-liquid ratio of 1/8 and 20 min residence time, but the leaching efficiency using nitric and hydrochloric acids are higher than the sulphuric acid. Furthermore, it was found that microwave pre-treatment improves the leaching efficiency of REEs.