VictorJuiz/thesis huggingface dataset:
Understanding and Supporting Anticipatory Driving in Automated Vehicles
Keywords: Driver behavior
Driver distraction
Driving automation
Driving simulator
Experience
Visual attention

With state-of-the-art driving automation technology available to the public (i.e., SAE Level 2 driving automation), drivers no longer need to control the vehicle continuously, but are still required to monitor the road and the automation, and take over control or adjust the automation’s setting when necessary. Thus, many driving skills, such as anticipatory driving, which can allow drivers to predict potential traffic changes and respond to them in advance, can still enhance driving safety in automated vehicles. Anticipatory driving has already been found to be more prevalent among experienced drivers in non-automated vehicles. However, the factors influencing anticipatory driving in automated vehicles has not yet been investigated. Thus, this dissertation aims to understand anticipatory driving behaviors in automated vehicles and investigate displays that can support it. Three driving simulator experiments were conducted. The first experiment investigated the relationships between anticipatory driving, distraction engagement, driving experience, and visual attention allocation in non-automated vehicles. The second experiment re-investigated the factors mentioned above in a simulated automated vehicle equipped with adaptive cruise control and lane keeping assistance. The third experiment investigated the effectiveness of two displays in supporting anticipatory driving among experienced and novice drivers in automated vehicles, i.e., a TORAC display with takeover request (TOR) and automation capability (AC) information, and a STTORAC display with surrounding traffic (ST) information in addition to the TORAC display. Results show that in both automated and non-automated vehicles, experienced drivers exhibited more anticipatory driving behaviors, and distraction engagement impeded anticipatory driving for both novice and experienced drivers. Further, allocating more visual attention toward cues indicating upcoming events increased the odds of exhibiting anticipatory driving behaviors in non-automated vehicles. For automated vehicles, it was found that drivers’ reliance on automation might have a larger impact on the performance of anticipatory driving compared with visual attention to cues. The TORAC display led to less anticipatory driving in automated vehicles, possibly because it led to over-reliance on automation. Providing additional context information in the STTORAC display presumably supported drivers’ anticipation of potential traffic conflicts.
Handheld Microfluidic Bioprinter for In Situ Delivery of Skin Tissue Constructs
Keywords: Biomaterials
Bioprinting
Medical Devices
Microfluidics
Tissue engineering

Full-thickness burns where both the epidermal and dermal layer of the skin are destroyed lead to high patient mortality due to complications like dehydration, infection, and shock. The current standard of care involves isolating healthy skin from uninjured regions, followed by meshing and grafting onto the debrided wound site. However, this approach is not appropriate for patients with large area burns covering over 40% of the total burn surface area as insufficient quantities of healthy skin remain. Although many bioprinting approaches have been developed to meet this demand by converting biopolymer solutions, or “bioinks”, into three-dimensional tissue structures, current bioprinters are primarily designed for laboratory use and allow only small, centimeter-sized tissues to be prepared. Here, a novel handheld bioprinting system for in situ delivery of cell-containing biomaterial constructs was designed to deliver a variety of cell types embedded in alginates, collagens, or fibrins, accounting for unique physical properties and gelation mechanisms of each biomaterial. This technology was shown to be compatible with primary keratinocytes, dermal fibroblasts, and mesenchymal stem cells, allowing cell organization into distinct patterns such as stripes, spots, and bilayers using a microfluidic printhead. To enable conformal and consistent biomaterial construct delivery onto physiological substrates, a two degree-of-freedom rotational printhead and a compliant silicone wheel was integrated into the printhead setup. A fibrin-hyaluronic acid bioink composition was optimized to promote the formation of tissue constructs on tilted surfaces, balancing appropriate enzymatic gelation times with resistance to material drainage. In a case study to determine the utility of this approach, mesenchymal stromal cells delivered using the handheld bioprinter were shown to improve wound healing outcomes on four porcine models of full-thickness burn. Lastly, the capabilities of the instrument were further developed by implementing active and passive temperature control to allow consistent deposition of collagen-based bioinks, and by integrating disposable thermoplastic printheads fabricated using silicon wafer-based thermal embossing to enable sterile operation in a clinical setting. Taken together, this handheld bioprinter enables the conformal delivery of cell-containing extracellular matrix bioinks in situ and lays the foundation for future human clinical trials for the treatment of large-area, full-thickness burns.
Three Essays on Empirical Asset Pricing
Keywords: cross-section of stock returns
idiosyncratic volatility
implied volatility spread
option returns
stock return autocorrelation
time-series stock return predictability

This dissertation contains three essays on empirical asset pricing. In the first essay, I study the relationship between idiosyncratic volatility and expected returns of risky assets. I find that when the true asset pricing model cannot be identified, the idiosyncratic volatility obtained from a misspecified model contains information regarding the hedge portfolio in Merton’s (1973) ICAPM. Empirically, I find that from 1815 to 2018, a combination of equal-weighted idiosyncratic volatility (EWIV) and value-weighted idiosyncratic volatility (VWIV) can strongly forecast stock market returns over short- and long-term horizons. Furthermore, EWIV and VWIV jointly can explain the cross-section of average stock returns. I show that the combination of EWIV and VWIV is a proxy for the conditional covariance risk in the ICAPM. The deduction also provides new insights concerning the tail risk measure proposed by Kelly and Jiang (2014). The second essay is a joint work with Bing Han. We propose a new and robust predictor of stock market returns and real economic activities based on information from equity options. We aggregate the difference in implied volatilities of at-the-money call and put options across stocks and find that the aggregate implied volatility spread (IVS) is significantly and positively related to future stock market returns. We attribute the predictive power to common informed trading in equity options instead of time-varying risk premium. The third essay, coauthored with Yoontae Jeon and Raymond Kan, studies the expected option return under an extended Black-Scholes model that incorporates the presence of stock return autocorrelation. We show that expected returns of both call and put options are increasing functions of return autocorrelation coefficient of the underlying stock. We find strong empirical evidence from the cross-section of average returns of equity options to support this prediction. Average returns of calls and puts as well as straddle returns all show monotonically increasing relationship with the degree of underlying stock’s return autocorrelation coefficient. We also examine how the information on stock return autocorrelation helps investors to improve the out-of-sample performance of their portfolios.
Control of Multiple Magnetic Microrobots for Biomedical Applications
Keywords: 3D micromanipulation
Medical robotics
Microrobotics
Multi-agent control
Targeted cargo delivery
Underactuated robotics

My PhD dissertation takes an innovative approach to using the fundamental tools of robotics and control to solve the underactuated control problem of multiple magnetic microrobots for biomedical applications. The ability to use a team of microrobots to run a task can offer many advantages. However, the integration of on-board powering and sensing circuitry has not yet become possible at the microscale. Therefore, all magnetic microrobots (micro-agents) of the team have to share a single driving signal, whereas the system has multiple states to be independently controlled. Another major challenge with magnetic team control is that when multiple magnetic microrobots work together in close proximity, the agents tend to irreversibly stick together due to strong magnetic inter-agent forces. Previous studies either ignored the inter-agent forces by simply assuming their robots were far apart or treated these forces as disturbances without verifying the stability in close proximity. I solved for the first time this problem for a pair of magnetic agents in close proximity in 2D (and later in 3D) by making full use of inter-agent forces to control the motion of agents. In my approach, the positions of microrobots were controlled independently. As a practical demonstration, I showed for the first time that the motion of two functional magnetic microrobots as microgrippers can be controlled in 3D to run a task. Subsequently, to generalize the inter-agent force control to more agents, I introduced two solutions: 1) via optimization-based control (as a control technique), and 2) via motion planning and tracking (as a robotics technique). My PhD research enabled for the first time the collision-free autonomous navigation of a team of magnetic microrobots in close proximity. This solution allows magnetic microrobots to potentially act in a cluttered environment, such as the human body or microfluidic channels. To this end, I employed rapidly-exploring random tree (RRT) motion planning. I further incorporated the idea to run two practical demos that could be applied to cell testing/manipulation. The results of this PhD work can be applied to actuation and sensing, especially in the design of field-activated medical devices and for localized targeted drug delivery.
Binding and Uptake of Single and Dual-opsonized Target Particles by Macrophages
Keywords: C3bi
crosstalk
IgG
macrophages
opsonin
phagocytosis

Phagocytosis is an evolutionarily conserved mechanism that serves as the first line of host defense in multicellular organisms. Phagocytes are exposed to a variety of ligands on heterogeneous target particles in vivo, and this recognition is driven by an extensive repertoire of receptors with distinct ligand specificity. However, our current view of phagocytosis has been shaped by studying individual receptor-ligand interactions and their downstream signaling pathways. This makes it physiologically relevant to observe the simultaneous engagement of multiple phagocytic receptors and the underlying coordination of downstream signaling pathways for efficient phagocytosis. Potential crosstalk between the two well-characterized opsonic receptors, FcγR and CR3, was briefly explored in the early 1970s, where macrophages were challenged with dual-opsonized target particles. However, subsequent studies on receptor crosstalk have been primarily restricted to the use of single opsonin on different target particles and typically presented at relatively high opsonin concentrations to induce maximal receptor engagement and signaling. Beyond validating these initial explorations on receptor crosstalk, we attempted to identify the early signaling mechanisms that underlie the binding and phagocytosis of dual-opsonized target particles (IgG and IgM/C3bi) during the simultaneous activation of both opsonic receptors, compared to single receptor activation. For this purpose, we used signaling protein inhibitor studies as well as live-cell brightfield and fluorescence imaging to fully understand the role of cytoskeletal elements and tyrosine kinases, F-actin dynamics, internalization kinetics and phagosome maturation rates for FcγRs and CR3. Importantly, opsonic receptors were studied together and in isolation, in the context of relatively low opsonin concentrations on target particles deemed optimal through flow cytometry analysis and particle binding assays. We saw enhanced particle binding and a synergistic effect on particle internalization when FcγRs and CR3 were simultaneously engaged with relatively low opsonin concentrations on target particles. Next, we investigated the early signaling requirements for the binding and uptake of single and dual-opsonized particles. Inhibition of early signaling and cytoskeletal molecules revealed a differential involvement of Src kinase for FcγRs- versus CR3- and dual receptor-mediated phagocytosis. Src activity recruits Syk kinase, and we observed intermediate levels of Syk phosphorylation in dual-opsonized particles compared to those opsonized with IgG or IgM/C3bi alone. These results likely correlate to the intermediate levels of F-actin that is recruited to sites of dual-opsonized particle uptake and underlie the notoriously delayed internalization of IgM/C3bi-opsonized target particles by macrophages.
An Examination of Instagram Use and Body Image in a Sociocultural Model of Disordered Eating
Keywords: body image
disordered eating
emerging adulthood
Instagram
social media
thin-ideal internalization

Instagram has been identified as a particularly problematic social media site for emerging adults and has been linked to body image concerns (Fardouly, Willburger, Vartanian, 2018) and disordered eating (Holland Tiggemann, 2017; Turner Lefevre, 2017). There is limited research on the mechanisms that underlie the relationship between the use of image-based social networking sites, such as Instagram, and disordered eating. Phase I of the present study assessed thin-ideal internalization, appearance comparison, and body dissatisfaction as mediators of the relationship between frequency of overall Instagram use and disordered eating. One hundred and sixty women (ages 18-24) completed questionnaires regarding frequency of Instagram use, thin-ideal internalization, trait appearance comparison, body dissatisfaction, and disordered eating. Frequency of Instagram use and thin-ideal internalization were directly and separately associated with body dissatisfaction and disordered eating. The proposed mediators were not found to underlie the relationship between Instagram use and disordered eating. To date, there is limited research on how Instagram use impacts daily experiences of mood and body dissatisfaction, which has important implications for capturing potential negative effects of Instagram use on women’s lives. Daily changes in mood and body dissatisfaction might influence decisions to engage in weight control behaviours and cannot be fully captured through retrospective assessment. In order to make research-based recommendations regarding Instagram use, we need to know more about how it impacts users daily. In Phase II of the present study, ninety-two women (ages 18-24) who completed Phase I were randomly assigned to an experimental (Instagram) or control (Reddit) condition and completed daily measures of mood and body dissatisfaction pre- and post-Instagram (or Reddit) use. Body dissatisfaction increased significantly post-Instagram use. In addition, participants low on trait appearance comparison experienced greater positive affect post-social media exposure. Findings from the current study reveal the potentially harmful impact of brief exposures to Instagram use, specifically on how women feel about their bodies and, more broadly, how they feel in general. Policy implications include social media companies ensuring safer online platforms and educational initiatives aimed at increasing young women’s body satisfaction and reducing tendencies to engage in appearance comparisons while online.
Teachers Navigating Their Experiences of "Going Gradeless" in Ontario, Canada
Keywords: assessment
competency
feedback
gradeless
Growing Success
teacher

The purpose of this qualitative study was to explore the experiences of Ontario secondary school teachers, navigating conceptual, pedagogical, cultural and political challenges as they shifted their practice from marks to "gradeless". Twenty-eight teachers from fifteen schools in seven school districts in the province of Ontario in Canada participated in semi-structured, face-to-face interviews. The 28 teachers in this study shared complex journeys of growth and innovation, providing feedback and supporting student learning through use of clear goals, and explicit communication of success criteria. The study provides models of gradeless classroom assessment that range from hidden or deferred marks to four-level rubrics to single-point rubrics to rich descriptive feedback, and from task criteria to curriculum expectations to overarching learning goals. The interviewees described concepts of assessment that centre on the learner, and pedagogical approaches that support student voice and choice. They experienced challenges from the cultural expectations of students, parents and colleagues, but none of the interviewees were restricted by policy requirements from making the changes in assessment practice that they identified as "gradeless", and which serve to support the learning of their students. This study suggests that teachers' conceptual understanding begins with their personal experiences of assessment, is developed through the pedagogy they employ, the cultural influences on their professional and school community, and the policy that underpins their practice. The study demonstrates that when teachers discover processes that improve the achievement of their students, they will persist with the new process even if faced with strong cultural pressure. It suggests that greater communication to, and education of, the school community, parents and students is needed to shift cultural expectations of assessment. The study reveals that given clear policy, grounded in research, teachers can develop stronger conceptual understanding of assessment, and are empowered to move forward, even in the face of strong cultural pressures. Implications for future research in classroom assessment, teacher change, and 21st century learning are further discussed.
Change for Orchestra and Soprano
Keywords: Orchestra
Orchestra and Voice
Voice

“Change” is a 16-minute composition for soprano soloist and orchestra. It uses shifting timbres, colours and the cyclic use of motives and harmonic ideas to evoke notions of the resiliency of human spirit. “Change” sets Raymond Knister’s poem of the same title, which is in the public domain. The orchestral instrumentation comprises of: piccolo, two flutes, two oboe, three clarinets (third double bass clarinet), three bassoons; four horns, two trumpets in B flat, two tenor trombones, bass trombone, tuba; timpani, three percussion (bowed vibraphone, bass drum, tubular bells, bowed crotales, glockenspiel, marimba, handbells); harp, and strings (suggested 16 14 10 10 6). “Change” uses a linear form in seven sections (relating to the structure of the text). The work in some sense is one large blossoming and decaying musical gesture; the composition slowly develops into a full tutti musical gesture which then gradually decays away into similar music to that which opened the work. “Change” explores various changes in orchestration and colour with most sections of the work exploring a variation in timbre or instrumentation. The music moves from hushed delicate gestures to a darker rich harp and marimba colour, and then to a full shimmering brass hue. The music shifts away from the brass texture to a more sparse colour; glissandi trombones, delicate string writing on harmonics with fleeting flute flutterings and lip bends above. Then the music beings to combine instrumental families as it builds to tutti writing for the orchestra. A chorale melody begins to drive the music to the climactic phrases. The piece ends in a similar style as it began, with delicate, hushed gestures, though developed through inversion and slight variations in retrograde: motifs are re-interpolated and transformed as if upon reflection they have grown and evolved, akin to how humans grow and reflect at certain stages in our lives; we may continue to live a similar life as we did years ago, but we change and reorientate ourselves. The music is left open-ended, peacefully evaporating into nothing, it’s as if moments of our life pass us by and are now only a memory.
Manganese-based Positive-contrast MRI for Non-invasive Monitoring of Biomaterials and Cells in Tissue Engineering
Keywords: Cell Tracking
Magnetic Resonance Imaging
Manganese
Porphyrin
Scaffold Monitoring
Tissue Engineering

Cells and scaffolds are the pillars of tissue engineering and regenerative medicine. They have the potential to regenerate any tissue or organ; however, a major unmet challenge limiting their clinical translation is the absence of non-invasive technologies for spatial and temporal tracking of implant fate in deep tissue and with high spatial resolution. Contrast-enhanced magnetic resonance imaging (CE-MRI) is highly suited for this task; however, current methods suffer from contrast agent toxicity or fail to provide longitudinal monitoring with high sensitivity and specificity. To address this need, this thesis aims to further develop positive-contrast MRI with manganese (Mn), an essential micronutrient, for in vivo imaging and tracking of cells and scaffolds. To image scaffolds and track their fate, biomaterials were labelled with manganese porphyrin (MnP) contrast agents, which exhibit anomalously high T1 relaxivity and form stable Mn-chelates. Atypical conjugation approaches were explored to achieve facile, biocompatible and efficient labelling of a variety of decellularized extracellular matrix and collagen-based scaffolds including injectable hydrogels, tissue grafts and whole organ constructs. This thesis demonstrates the first report to track these materials in vivo with CE-MRI and the potential for quantitative tracking of degradation over time. For non-invasive cellular MRI, both direct and indirect labelling techniques with Mn-based agents were designed to guide cell injection in real-time and probe cell fate longitudinally. Firstly, the utility of a commercially scalable MnP agent for safe and highly efficient labelling of human embryonic stem cells was demonstrated ex vivo. MR imaging of the labelled cells permitted detection of early cell fate and injection success in vivo. Secondly, to track cells longitudinally with high sensitivity and specificity, a reporter gene platform, bright-ferritin, was designed to produce endogenous T1-cellular contrast by the formation of manganese-ferritin nanoparticles intracellularly. The bright-ferritin system exhibited superior relaxivity and contrast generation in vitro and in vivo over conventional T2 iron-ferritin systems and T1 manganese-transporter systems. This bright-ferritin platform has the potential for on-demand, longitudinal, and sensitive, quantitative cell-tracking in vivo. Overall, this body of work demonstrates the utility of Mn-based bright-MRI for the assessment of scaffold and cell implantations.