VictorJuiz/thesis huggingface dataset:
Rule-based Adversarial Learning: Disguising and Recognizing Maliciousness in Opcodes

Adversarial learning has previously demonstrated effectiveness as a tool for improving performance in deep learning models trained on limited data. In this work, we apply adversarial learning to the constrained, discrete domain of opcode-based deep malware detection. We do this by developing a deep learning model for detecting maliciousness in sequences of opcodes, and using this model in order to alter sequences of code from the dataset in minimal ways to create example sequences which are misclassified by the original model. We augment our original training dataset with these adversarial examples, thereby improving the classification accuracy on unseen sequences of opcodes. Using adversarial examples to supplement our training data, we demonstrate statistically significant increases in performance (> 0.5% increase in both accuracy and F1-score). Additionally, we present a preliminary investigation into the transferability of our adversarial examples between different model architectures.

Keywords: Adversarial Learning
Malware Detection
Opcode
Advisor: Lawryshyn, Yuri A
An Exploration of Knowledge Practices Among User Experience (UX) Professionals

This qualitative, exploratory research investigated the knowledge practices of User Experience (UX) designers, an emerging, knowledge-intensive profession that has not been well studied. Three areas of exploration included the way UX designers share knowledge, manage knowledge in work contexts, and participate in communities of practice (CoPs). Grounded Theory Method was employed to generate two frameworks of knowledge sources, based on 10 emergent themes from 21 interviews with UX professionals: Knowledge Sources in Work and Knowledge Sources in Career Development. These frameworks illustrate sources of knowledge that UX professionals use in their work and throughout their career. They make use of explicit knowledge, tacit knowledge, and CoP participation to help identify suitable work processes. In addition, experience and the level of UX maturity in organizations influence the knowledge sources they use. UX professionals and organizations will find value in these frameworks for enhancing practice and supporting UX career development.

Keywords: community of practice
grounded theory
knowledge sharing
knowledge sources
user experience design
UX maturity
Advisor: Furness, Colin
Design, Development, and Evaluation of a Voice Based Chronic Disease Management Program

Digital therapeutics is a new and emerging category of digital health technology being used to help scale effective chronic disease management and prevention and is commonly deployed through smartphone apps. Medly is an example of a digital therapeutic used for heart failure self-management, with previous studies demonstrating the program’s ability to reduce health service utilization and improve clinical, quality of life, and patient self-care outcomes. Although these results show promise, these programs can be more accessible by offering them using alternative platforms. This research investigated whether voice apps can be a practical alternative of enabling patients to receive a digital therapeutic. A user-centered design process was followed and a voice app of Medly was built based on a design research process which included a usability study. Findings from the pilot study showcased the potential benefits this technology has for particular patients by enabling a more accessible model of health-care delivery.

Advisor: Cafazzo, Joseph
Investigation of the Relationship between Ascending Thoracic Aortic Aneurysm Hemodynamics and Arterial Wall

Ascending thoracic aortic aneurysms (ATAAs) are an unphysiological expansion of the arterial wall, leading to aortic dissection and rupture. Timing of surgical intervention is predominantly based on maximal diameter; however, this criterion is known to be unreliable and does not incorporate the multitude of factors that lead to complications. This work investigates the role hemodynamics play in the pathophysiology of ATAAs and investigates potential hemodynamic metrics to evaluate complication risk. In this context, a protocol was developed to create computational fluid dynamics (CFD) models of ATAA hemodynamics. Following the development of this protocol, the relationship between hemodynamic indices and arterial wall biomechanical properties was studied in a cohort of five patients. The findings from this study suggest that hemodynamically induced shear forces are associated with the degradation of arterial wall viscoelastic hysteresis and delamination strength. These findings warrant further investigation of the use of hemodynamic metrics to identify ATAA complication risk.

Advisor: Amon, Cristina
Device Engineering and Outdoor Weathering of Novel Tri-layer and Bi-layer Organic Photovoltaic Devices using Boron Subphthalocyanine and its Derivatives

Organic solar cells are gaining interest commercially and in academia due to their ease of manufacturing and low-cost materials. Currently, they are less efficient than commercially available silicon solar cells and their long-term degradation is not well known. A commonly used material in organic solar devices is boron subphthalocyanine, which has strong absorbance at the peak of the solar spectrum at wavelengths between 500 and 600 nm. In this work, I fabricated novel multi-layer devices using boron subphthalocyanine and its derivatives, with the goal of increasing the power conversion efficiency above baseline bi-layer devices. I fabricated novel devices utilizing boron subphthalocyanine as an electron donor and an electron acceptor. Simultaneously, I tested the outdoor long-term degradation of the novel devices on a custom rooftop testing apparatus to ensure they maintain high performance over long periods of time.

Keywords: Ageing
Boron Subphthalocyanine
ISOS
Multi-layer
Organic
Solar
Advisor: Bender, Timothy P
Uncertainty-constrained Trajectory Optimization in Belief Space for Vision-based Robots

Planning in belief space provides a unified approach to tightly couple the perception, planning and control modules, leading to trajectories that are aware of the detrimental effects of environments with varying information content. However, existing methods handle uncertainties as costs that require manual tuning for varying environments and hardware without explicit guarantees of localization quality. Furthermore, many extrinsic sensors, such as cameras are viewpoint limited, leading to discontinuous belief dynamics that cause belief space trajectory optimization methods to fail. We therefore propose a novel trajectory optimization formulation that incorporates inequality constraints on uncertainty and a novel Augmented Lagrangian based stochastic differential dynamic programming method in belief space. Furthermore, we develop a probabilistic visibility model that accounts for discontinuities due to feature visibility limits. The resulting algorithm thus has the ability to incorporate viewpoint limitations and select non-myopic active perception control actions that are informed by localization uncertainty along the trajectory.

Keywords: Belief Space
Uncertainty-constrained
Vision-based planning
Advisor: Waslander, Steven SLW
Combining a Smartphone App into a Web-based Smart Survey Tool

Smartphone-based travel data collection has been a trending topic in the transportation industry, which is believed to have many advantages over traditional travel survey methods, including reducing respondent burden and providing frequent updates. Smartphone-based travel data collection involves passively collecting participants’ travel data through designated smartphone apps. This thesis proposes to incorporate smartphone-based travel data collection with an in-house online travel survey platform named TRAISI to form a web-based smart survey tool. Travel mode detection algorithms and trip purpose inference algorithms are investigated so that trip modes and purposes can be inferred from passively collected smartphone location data. The integration between smartphone collected data and the TRAISI platform is discussed, and the current design of the web interface is presented. The proposed system can take advantage of both the online travel survey platform and smartphone-based passive data collection to make travel surveys more efficient and less burdensome for respondents.

Keywords: Household travel survey
Machine learning
Smartphone-based travel survey
Travel mode detection
Trip purpose imputation
Web-based travel survey
Advisor: Miller, Eric J
Habib, Khandker Nurul
Effects of Flow Field and Spray Characteristics on Soot in a Swirl-stabilized Model Combustor

The effect on spray structure, flow field, and sooting characteristics of swirl-stabilized neat Jet A-1 spray flames with n-Pentanol addition was investigated. n-Pentanol addition up to 20% by thermal power was added to neat Jet A-1 fuel to produce flames with a constant thermal output of 8.83 kW. Two air flow rates were used to produce two globally fuel-lean mixtures. Fraunhofer diffraction characterized the fuel spray while stereoscopic particle image velocimetry was used to visualize the flow field. Auto-compensating laser-induced incandescence was used to measure soot volume fraction and primary soot particle diameter at various locations in the flame. Noticeable variations in spray structure were measured with n-Pentanol addition compared to neat Jet A-1 flames. Soot was detected below 40 mm axially with 10% n-Pentanol addition which was explained by the increased evaporation rates of the fuel with n-Pentanol addition. Total soot loading in the combustor decreased monotonically with increasing n-Pentanol addition.

Keywords: Jet A-1
LII
model-validation suited data
n-Pentanol
soot
SPIV
Advisor: Gülder, Ömer L.
R2* and Magnetic Susceptibility Mapping for Quantifying Radiation-induced Alterations in Brain Development in a Mouse Model

Brain and spinal cord tumors are the second most common childhood cancers after leukemia. The method of care generally includes cranial radiation therapy (CRT). The probability of survival after treatment is approaching 90%, however survivors are at a significant risk for neurocognitive deficits known as late effects. Human and mouse MRI studies have shown that these cognitive late effects in children are associated with reduced white matter volume that is detectable shortly after irradiation and persists long term. Quantitative MR imaging techniques can characterize brain properties in addition to volume that may provide sensitivity to other indicators of tissue health. In this thesis, I demonstrate that mapping of R2* and quantitative susceptibility with ex vivo MRI reveals prominent CRT-induced changes in white matter with more subtle differences in cortical and subcortical brain regions.

Keywords: late effects
MRI
quantitative susceptibility mapping
R2*
white matter
Advisor: Nieman, Brian J
The Effects of Aging and Hearing Abilities on Perception of Face Identity and Emotion, and their Interference

Successful recognition of facial identity relies primarily on information in the top-half of a face, the identification of some emotions (e.g., disgust) relies more on the lower-half. Although younger adults (YAs) can flexibly extract information from relevant regions depending on the task, older adults (OAs) are less consistent in this ability. One reason may be that OAs attend more to visual information from the lips to aid speech perception due to hearing loss. We evaluated hearing abilities and both identity and emotion perception of faces in 84 YAs and 152 OAs, when identity and/or emotion could be either consistent or different across comparator faces. OAs outperformed YAs for emotion perception, while the opposite trend was found for identity. Identity changes didn’t interfere with either group’s emotion perception, but OAs’ identity perception was more interfered by emotion changes than Yas. In addition, the disgust interference effect was found not different from zero only in younger but not older adults. All three pieces of evidence suggested OAs extract more information from the lower-half of a face regardless of the task. In OAs, worse hearing was related to worse emotion and identity perception, but not to the interference. Future study will elicit the hearing abilities effect by presenting acoustic stimuli and face stimuli simultaneous, and explore how emotion interfere with work memory capacity of faces in OAs.

Advisor: Sekuler, Allison B
Herrmann, Björn
Opioid Disposal Practices of Patients with Life-limiting Cancers in an Outpatient Palliative Care Clinic: A Cross-sectional Study

Introduction: Proper prescription opioid disposal is essential to prevent poisonings and deaths. This study examined the opioid disposal practices of Princess Margaret Cancer Centre Outpatient Palliative Care Clinic (OPCC) patients. Methods: This cross-sectional study involved a retrospective chart review of new, adult patients who were seen in the OPCC (September 2018 – August 2019) and completed a survey about opioid use. Results: 58/111 (52.3%) of study participants did not routinely dispose of their opioids. Cannabis and neuropathic medication use (OR 3.0, 95% CI 1.2 – 7.2) were positively associated with routine disposal of opioids. Patients were less likely to routinely dispose of their opioid if they responded “Yes” to “Have you had to increase the amount of opioids you take over the past six months?” (OR 0.38; 95% CI, 0.16 - 0.88). Conclusion: There is a high prevalence of people with life-limiting illnesses who do not routinely dispose of their opioids.

Keywords: Cancer
Disposal
Opioid
Palliative
Advisor: Furlan, Andrea D
The Liturgical Significance of the Old Hispanic Ad Pacem

One of the most unique features of the Old Hispanic Liturgy is the set of chant propersrelated to the sign of peace during Mass, designated as the prayers Ad Pacem. The texts of these prayers reflect some of the most important goals which Isidore of Seville and other Iberian clergy tried to implement through the councils which were held throughout Spain in the wake of the Visigothic conversion from Arianism. The most notable theme in this vein is the rejection of scandal caused by practices that gave a false impression of heresy. The significance of this moment also extends to the position of the sign of peace in the Old Hispanic liturgy, which illuminates some of the competing influences on the Iberian Peninsula from Rome, Africa, and the Byzantine Empire, allowing for a more comprehensive understanding of how multiple rites evolved in the West during late antiquity.

Keywords: Isidore
Liturgy
Mass
Medieval Iberia
Visigoths
Advisor: Haines, John
The Role of Schwann Cells in Corneal Maintenance and Healing

Corneal nerves play a crucial role in maintaining corneal health, including regulating the activity of stem cells in the limbus, the transitional zone between the cornea and sclera. The loss of these limbal stem cells (LSCs) leads to neurotrophic keratopathy (NK), with corneal ulceration, scarring, and ultimately, blindness. Having identified nerve-ensheathing Schwann cells (SCs) in the limbus, we hypothesized that SCs play a crucial role in corneal epithelial maintenance and healing via paracrine interaction with LSCs. We demonstrated that i) many SCs in the limbus are located in close spatial vicinity to LSCs and ii) the limbal SCs are important for corneal wound healing. These findings suggest that paracrine SC-LSC interactions may be responsible for the limbal nerve-mediated activation of LSCs during epithelial wound healing after injury.

Advisor: Borschel, Gregory GB
Gordon, Tessa TG
Selective Laser Melting of a High-strength Steel and Joining of Aluminum and Copper

Selective laser melting (SLM) is an additive manufacturing technique that employs a high energy density laser beam to fuse metallic powders for producing three-dimensional parts. The first part of this thesis focuses on employing recycled maraging steel powder in the SLM process. The steel samples produced with recycled powder exhibits nearly identical microstructure and mechanical properties to those produced using virgin powders. The second part of this thesis demonstrates that the SLM technique can be used to join dissimilar printed materials (pure Al and Cu, respectively) with 316L stainless steel. Pure Al and Cu powders join the steel through dissolution and melting. This thesis provides a preliminary study towards using recycled metal powders in the SLM processing and paves the way for joining dissimilar materials using the SLM.

Advisor: Zou, Yu
Azimi, Gisele
Elucidating the Role of Pten in a Newly defined G0-GALERT Transition in Mammalian Müller glia

Müller glia are endogenous retinal glia that act as adult stem cells in fish and frogs, replacing dying cells due to injury or disease. However, mammalian Müller glia have lost this ability to self-heal. In fish and frogs, the first regenerative step is the repositioning of glial nuclei outside of their inner retinal monolayer in a process known as interkinetic nuclear migration. Herein we discover that the conditional knock-out (cKO) of Phosphatase and tensin homolog (Pten) in mammalian Müller glia leads to spontaneous interkinetic nuclear migration, altered lineage marker expression in displaced glial cells, and an enhanced proliferative response to retinal injury. We further found an upregulation of mTORC1 activity supporting the idea that these glial cells have transitioned to a metabolically active state, priming them to respond to injury, akin to the G0-GALERT priming step seen in seen in other stem cell populations.

Keywords: cell migration
Muller glia
priming
Pten
regeneration
Stem cell
Advisor: Schuurmans, Carol J
Self-calibration of the Offset between GPS and Semantic Map Frames for Robust Localization

In self-driving, GPS is generally considered to have insufficient positioning accuracy to stay in lane. Instead, many turn to LIDAR localization, but building and maintaining LIDAR maps can be costly. Another possibility is to use semantic cues such as lane markings and traffic lights to achieve localization, but these are usually not continuously visible. This can be remedied by combining semantic cues with GPS to fill in the gaps. However, due to biases accumulated between mapping and localization, the live GPS frame can be offset from the semantic map frame, requiring calibration. In this thesis, we propose a robust semantic localization algorithm that self-calibrates for the GPS-to-map offset by exploiting common semantic cues. We formulate the problem using a modified Iterated Extended Kalman Filter, which incorporates GPS and camera images for semantic cue detection. Experimental results show that the proposed algorithm achieves decimetre-level accuracy and is robust against sparse semantic features and frequent GPS dropouts.

Keywords: Autonomous Vehicle Navigation
Localization
Sensor Fusion
Advisor: Barfoot, Timothy D
Schoellig, Angela P
Tactile Afference in Online Movement Guidance to a Body Location

Like visual motion, tactile motion conveys the direction and magnitude of changes in target location (e.g., catching a slipping towel on the body). The current thesis explored tactile-based corrections to the perturbation of a target on the body and visual-based corrections to a target in the extracorporeal space. When participants only had to detect the target motion, a moving tactile target was detected earlier than a moving visual target. In contrast, in the reaching task, participants took longer to initiate limb trajectory amendments to moving tactile than visual targets. Also, when the target was perturbed toward the participant, there were larger correction magnitudes in the visual than in the tactile target condition. Such difference can be explained by the capacity of the tactile and visual receptors as well as the experimental. Overall, these findings may reflect different sensorimotor processes underlying the detection and planning of movements toward tactile stimuli.

Keywords: Goal-directed movement
Motor control
Online-control
Perception-action
Tactile feedback
Visual feedback
Advisor: Tremblay, Luc
Postoperative Buprenorphine Discontinuation in Continuously Treated Buprenorphine Patients: A Population Cohort Study

Sudden discontinuation of buprenorphine in opioid use disorder increases the risk of relapse and overdose. The thesis objective was to understand patient, procedural, opioid treatment-related and health service use factors associated with discontinuing buprenorphine after surgical discharge. A cohort study was conducted and included adults 18+ on stable buprenorphine preoperatively. Logistic regression modeling was used to study the association of the primary outcome (buprenorphine continuation within 14 days of surgical discharge) with demographic and treatment factors. 2176 patients were on stable buprenorphine prior to an incident surgery, and 176 (8.1%) did not resume buprenorphine postoperatively. Inpatient (versus ambulatory) surgery was associated with reduced continuity, with an OR of 0.16 (95% CI 0.11, 0.23) after adjusting for demographic and treatment factors. Most patients continued buprenorphine postoperatively, although inpatient surgery is a strong predictor of discontinuity, suggesting that buprenorphine treatment should be coordinated between inpatient and outpatient providers to improve buprenorphine continuity.

Keywords: Buprenorphine
Cohort Studies
Opioid-Related Disorders
Surgical Procedures
Advisor: Kurdyak, Paul
Exploring the Role of Emotion Dysregulation and Coping Motives on Cannabis-related Consequences: A Daily Diary Study among Emerging Adults

Emerging adults (EAs; ages 18-25) have the highest rates of cannabis use and cannabis-related consequences relative to other age groups. There is substantial evidence pointing to emotion dysregulation and coping motives as important variables impacting cannabis-related consequences, however, current research is limited in examining their collective impact. The current study sought to explore trait-level facets of emotion dysregulation and state-level coping motives to determine their influence on cannabis-related consequences among EAs. Data were collected daily from 64 cannabis-using EAs who reported their cannabis use, motives, and consequences over 30 days. Emotion dysregulation was assessed at baseline. A mediation model was used to examine whether coping motives influence the relationship between emotion dysregulation and cannabis use. Hierarchical linear modelling tested whether emotion dysregulation facets moderated the within-person relationship between coping motives and cannabis problems. Findings highlight two significant facets of emotion dysregulation, Nonacceptance of Emotional Responses and Limited Access to Emotion Regulation Strategies, as contributing to coping-motivated cannabis use and subsequent cannabis-related consequences. These results help elucidate the underlying mechanisms that protect EAs from cannabis-related consequences and can be used to develop effective screening tools and interventions to help prevent problematic cannabis consumption.

Keywords: cannabis
coping motives
daily diary
emerging adults
emotion dysregulation
Advisor: Goldstein, Abby L