Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
Displaying 91 - 97 of 97
Description
Walking and mobility are essential aspects of our daily lives, enabling us to engage in various activities. Gait disorders and impaired mobility are widespread challenges faced by older adults and people with neurological injuries, as these conditions can significantly impact their quality of life, leading to a loss of independence and an increased risk of mortality. In response to these challenges, rehabilitation, and assistive robotics have emerged as promising alternatives to conventional gait therapy, offering potential solutions that are less labor-intensive and costly. Despite numerous advances in wearable lower-limb robotics, their current applicability remains confined to laboratory settings. To expand their utility to broader gait impairments and daily living conditions, there is a pressing need for more intelligent robot controllers. In this dissertation, these challenges are tackled from two perspectives: First, to improve the robot's understanding of human motion and intentions which is crucial for assistive robot control, a robust human locomotion estimation technique is presented, focusing on measuring trunk motion. Employing an invariant extended Kalman filtering method that takes sensor misplacement into account, improved convergence properties over the existing methods for different locomotion modes are shown. Secondly, to enhance safe and effective robot-aided gait training, this dissertation proposes to directly learn from physical therapists' demonstrations of manual gait assistance in post-stroke rehabilitation.
Lower-limb kinematics of patients and assistive force applied by therapists to the patient's leg are measured using a wearable sensing system which includes a custom-made force sensing array. The collected data is then used to characterize a therapist's strategies. Preliminary analysis indicates that knee extension and weight-shifting play pivotal roles in shaping a therapist's assistance strategies, which are then incorporated into a virtual impedance model that effectively captures high-level therapist behaviors throughout a complete training session. Furthermore, to introduce safety constraints in the design of such controllers, a safety-critical learning framework is explored through theoretical analysis and simulations. A safety filter incorporating an online iterative learning component is introduced to bring robust safety guarantees for gait robotic assistance and training, addressing challenges such as stochasticity and the absence of a known prior dynamic model.
ContributorsRezayat Sorkhabadi, Seyed Mostafa (Author) / Zhang, Wenlong (Thesis advisor) / Berman, Spring (Committee member) / Lee, Hyunglae (Committee member) / Marvi, Hamid (Committee member) / Sugar, Thomas (Committee member) / Arizona State University (Publisher)
Created2023
Description
Over the past several decades, middle-aged Americans have exhibited troubling trends of declining mental and physical health over successive cohorts. Interestingly, this trend has not been observed in peer nations in Europe, Asia, and Mexico. Later-born cohorts in other countries typically report better midlife mental and physical health than their earlier-born counterparts. It is less clear the extent to which physical pain shows similar trends to what has been observed in the U.S. and comparison peer nations. The goal of the current study was to examine how self-reports of pain have historically changed during midlife and investigate whether differences emerge between the U.S. and peer nations. We used harmonized data on pain from nationally representative longitudinal panel surveys from the U.S., 13 European nations, South Korea, and Mexico to directly quantify similarities and differences in historical change in midlife pain. Our results supported the hypothesis that midlife pain is higher amongst later-born cohorts in the U.S. A similar pattern of historical increases in pain was observed in Continental and Nordic Europe. In England, Mediterranean Europe, South Korea, and Mexico, the opposite pattern was observed with historical declines in pain. Historical increases in reports of pain in the U.S. emerged more quickly for later-born cohorts at earlier stages of midlife. These results suggest there could be aspects of American midlife today that are exacerbating reports of pain, and these aspects may be shared in some European nations but absent or less influential in other peer nations. Our discussion focuses on potential explanations for this pattern, such as population level discrepancies in health, differential use of health care services, and the inter/intrapersonal costs of westernization, as well as how pain is conceptualized across nations.
ContributorsSyed, Orchee (Author) / Infurna, Frank (Thesis director) / Corbin, William (Committee member) / Davis, Mary (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / Sanford School of Social and Family Dynamics (Contributor)
Created2023-12
Description
Previous evidence implicating fighting gameplay with markers for cardiovascular changes in response to stress appraisals emphasizes the plausibility of additional biopsychosocial factors varying between players and dictating gameplay changes (Porter & Goolkasian, 2019). The current study builds upon previous research using the Biopsychosocial Model of Challenge and Threat (Blascovich and Tomaka, 1996) alongside the Mental Load Rating Scale (Hughes, 2023) to link perceptions of increased stress during gameplay with increases in gameplay errors. Participants were allotted a set time to acclimate to fighting game mechanics, then began combo trials. The game used in research (Street Fighter 6) requires precise movements in rapid succession completion the completion of a “combo”. Competitive fighting game players were compared to players lacking fighting game experience in post-participation response measuring stress salience or hindrance perception, as well as total input error comparison. Current findings suggest Competitive fighting game players report factors such as spectator viewing and time limits as hindrances capable of being overcome as opposed to Noncompetitor reports of factors and stressors during game acclimation. Findings between Competitor and Noncompetitor groups allude to cultural significance when navigating gameplay. Future research should continue measuring sociocultural perception of stress when navigating specific genres of video game play and avenues for stress reappraisal techniques.
ContributorsDavis, Nicholas (Author) / Holloway, Steven (Thesis director) / Flores, Valerie (Committee member) / Davis, Mary (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2023-12
Description
Approximately 20% of youth experience mental health problems (Vasileva et al., 2021), and dimensions of early childhood temperament, specifically negative affectivity and effortful control, predict later mental health (Rothbart, 2007). Examining temperament using person-centered methods, particularly in stressful contexts, may improve our understanding of vulnerability to adolescent emotional problems. The current study examined whether specific patterns, or types, of infant temperament longitudinally predicted adolescent anxiety and depression symptoms and whether family relationship stress moderated this association. We hypothesized that infants with a Negative Dysregulated temperament would experience higher anxiety and depression symptoms in later childhood compared to those with a Typical Expressive temperament, and that family relationship stress would exacerbate this link. In an ongoing-longitudinal study of families with twins (N=563, 51% female, 29.8% Hispanic/Latinx, 58.4% White; Lemery-Chalfant et al., 2019), primary caregivers (PCs) reported on infant temperament at 12 months (IBQ; Gartstein & Rothbart, 2003, α=.74-.90). In a prior study (Murillo et al., 2023), latent profile analysis yielded three infant temperament types: Negative Dysregulated, Positive Well-Regulated, and Typical Expressive. PCs reported on partner strain (PSS; Schuster, Kessler, & Asseltine, 1990, α=.87) and family conflict (FCS; Porter & O’Leary, 1980, α=.80) at age 8 and a composite of these two measures represented Family Relationship Stress (r = .689). Confirmatory factor analysis was used to form Depression and Anxiety outcome composites based on PC (4 reports), secondary caregiver (2 reports), teacher (2 reports), and self-report (3 reports) measures of depression and anxiety symptoms collected from ages 8-11 (HBQ, Armstrong & Goldstein, 2003; BPI, Measelle et al., 1998, all α’s > .80). We randomly selected one twin from each pair and conducted regression analyses, and then used the second twin for an internal replication. Family relationship stress had a significant main effect on both anxiety and depressive symptoms. The Negative Dysregulated temperament type did not predict anxiety and depression at ages 8-11, however, it interacted with family relationship stress to predict anxiety and depression in 1 of 2 samples. When family relationship stress was low, the Negative Dysregulated type was significantly associated with higher anxiety and depression outcomes compared to the Typical Expressive type, and high family relationship stress was significantly associated with lower depression outcomes. Elucidating these longitudinal relations is important for informing early intervention and reducing the burden of adolescent psychopathology.
ContributorsSingh, Ajuni (Author) / Lemery-Chalfant, Kathryn (Thesis director) / Corbin, William (Committee member) / Davis, Mary (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / Sanford School of Social and Family Dynamics (Contributor)
Created2023-12
Description
Research on self-regulatory variables like mindfulness and effortful control proposes strong links with physical and mental health outcomes across the lifespan, from childhood and adolescence to adulthood and old age. One pathway by which self-regulation may confer health benefits is through individual differences in reports of and emotional responses to daily negative and positive events. Mindfulness is broadly defined as non-reactivity to inner experiences, while effortful control is broadly defined as attentional and behavioral regulation. Mindfulness and effortful control have both been conceptualized to exert their beneficial effects on development through their influence on exposure/engagement and emotional reactivity/responsiveness to both negative and positive events, yet few empirical studies have tested this claim using daily-diary designs, a research methodology that permits for examining this process. With a sample of community-dwelling adults (n=191), this thesis examined whether dispositional mindfulness (i.e., non-reactivity of inner experience) and effortful control (i.e., attention and behavioral regulation) modulate reports of and affective reactivity/responsiveness to daily negative and positive events across 30 days. Results showed that mindfulness and effortful control were each associated with reduced exposure to daily stressors but not positive events. They also showed that mindfulness and effortful control, respectively, predicted smaller decreases in negative affect and smaller increases in positive affect on days that positive events occurred. Overall, these findings offer insight into how these self-regulatory factors operate in the context of middle-aged adults’ everyday life.
ContributorsCastro, Saul (Author) / Infurna, Frank (Thesis advisor) / Doane, Leah (Committee member) / Davis, Mary (Committee member) / Arizona State University (Publisher)
Created2018
Description
The field of unmanned aerial vehicle, or UAV, navigation has been moving towards collision inclusive path planning, yet work has not been done to consider what a UAV is colliding with, and if it should or not. Therefore, there is a need for a framework that allows a UAV to consider what is around it and find the best collision candidate. The following work presents a framework that allows UAVs to do so, by considering what an object is and the properties associated with it. Specifically, it considers an object’s material and monetary value to decide if it is good to collide with or not. This information is then published on a binary occupancy map that contains the objects’ size and location with respect to the current position of the UAV. The intent is that the generated binary occupancy map can be used with a path planner to decide what the UAV should collide with. The framework was designed to be as modular as possible and to work with conventional UAV's that have some degree of crash resistance incorporated into their design. The framework was tested by using it to identify various objects that could be collision candidates or not, and then carrying out collisions with some of the objects to test the framework’s accuracy. The purpose of this research was to further the field of collision inclusive path planning by allowing UAVs to know, in a way, what they are intending to collide with and decide if they should or not in order to make safer and more efficient collisions.
ContributorsMolnar, Madelyn Helena (Author) / Zhang, Wenlong (Thesis advisor) / Sugar, Thomas (Committee member) / Guo, Shenghan (Committee member) / Arizona State University (Publisher)
Created2024
Description
As industries advance and automation becomes more prevalent, it is vital that safety remains at the forefront of discussions. To support this, Risk Management
standards have been developed and adopted for both North American and International
markets. Additionally, technical documents have been published to streamline risk
management processes. Part of these emerging technologies includes Collaborative
robots, each with specific methods tailored to their capabilities. These standards offer
guidance not only to end-users but also to Robot manufacturers, ensuring adherence to
safety standards and providing methods for risk mitigation. The risk levels and categories
are organized in a hierarchical structure, ranging from the most severe to negligible.
Under these standards, the process involves identifying risks, mitigating them, validating
the mitigation through verification, and solidifying the results. As technologies continue
to evolve, it is essential for standards to evolve accordingly to ensure optimal safety
levels when implemented correctly. Having effective risk management in place for all
Industrial Robot Systems is paramount to reduce liability and protect both operators and
assets. Detail key standards are that govern the realm of industrial robot systems for both
north America and the rest if the world as well as highlight robot manufacturers
adherence to the standards, response to safety, and how risk management can be applied.
ContributorsHall, Ammon (Author) / Gintz, Jerry (Thesis advisor) / Sugar, Thomas (Committee member) / Dehghan-Niri, Ehsan (Committee member) / Arizona State University (Publisher)
Created2024