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Modeling and Control of Aquatic Surface Robots with Application to Acoustic Telemetry
No full textThesis (Ph.D.)--Michigan State University. Electrical and Computer Engineering - Doctor of Philosophy, 2025Aquatic robots have recently generated significant interest as sampling platforms for environmental studies since their mobility allows for a greater breadth of experiments than more established stationary sensors. Two types of surface vehicles are considered in this work: steerable drifters and uncrewed surface vehicles (USVs). Comparing to underwater vehicles, both drifters and USVs have the advantages of being able to communicate with RF signals as well as localize themselves readily with GPS. Steerable and active drifters have emerged as promising new platforms that can modify their trajectories using rudders and through sparing application of thrusters. Such drifters retain the energy-efficiency advantage of passive drifters with added maneuverability. The first part of this dissertation focuses on the modeling, analysis, and control of active drifters with the motivation to use them as mobile sampling platforms in environments with pronounced ambient flows such as rivers and lakes with circulation structures. A dynamic model is developed for steerable and active drifters, which is then used for adaptive parameter estimation and reachability estimation. Optimal control of drifters to maintain them as energy-efficient platforms is also investigated in a one-dimensional setting. Sets of state-space locations where the optimal control changes can be thought of as curves parameterized by one of the costate variables. Such curves enclose regions in the state-space for which the optimal control is the same, allowing the state-space to be mapped to the optimal control. The optimal control may then be determined by state feedback, which is shown to be more robust than open-loop optimal control in simulation. The proposed optimal control is further validated by data collected in experimental trials. We further investigate the use of USVs for sensing applications such as acoustic telemetry. Aquatic acoustic telemetry is a widely-used method for tracking movements of animals and studying their behaviors. In acoustic telemetry animals are implanted with an acoustic tag broadcasting a unique identification code, which is decoded by an acoustic receiver. USVs and and Autonomous Underwater Vehicles (AUVs) are being increasingly used as mobile receiver platforms, but their performance as acoustic telemetry platforms is not well studied. This work characterizes the performance of a USV as an acoustic telemetry platform, which is then used to improve estimates of tag locations and to optimally select waypoints. The USV considered is intended to be a low-cost, easy-to-operate platform that can be constructed by non-experts. Detection efficiency, or the probability of successfully detecting an acoustic tag, is examined as a function of distance between the tag and the receiver. The effect of thruster use is also examined. This characterization is then used with a genetic algorithm to determine the optimal set of waypoints for the USV to localize acoustic tags, considering the trade-off between distance traveled and estimated localization error. Data consisting of successful and failed detections are used to determine the maximum a posteriori estimates of tag locations. Tag locations estimated from experimental data using the proposed method are shown to be more accurate than the typical presence-absence estimates of tag locations. The control of USVs has been widely studied; however, prior work has been primarily focused on continuous-time controllers. Limitations on computational power and actuator response can make such controllers difficult to implement. Event-triggered control, a control paradigm in which the applied control is updated when a condition on the state (called an event-trigger) is met, addresses these limitations. Prior work on event-triggered control has required that the continuous-time closed-loop system be input-to-state stable with respect to sampling error in the control. Due to the nonlinear, non-holonomic and underactuated nature of existing USV models, however, it may be difficult to prove input-to-state stability. This work proposes a novel means of designing event-triggers that relaxes this stability requirement. The proposed event-triggers are designed directly from a Lyapunov function for the system rather than comparison functions used in previous work on event-triggered control. For a continuous-time controller that is globally asymptotically stable, the control sampled using the proposed event-trigger is also globally asymptotically stable. This approach is validated with a simulation example. To mitigate Zeno behavior, a minimum inter-sampling interval is included in the design of the event-trigger. Although stability of the closed-loop system cannot be guaranteed with a minimum inter-sampling interval, convergence of system states to desired values is observed in simulation.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Nonfarm Work Among Crop Farmworkers in the United States
No full textThesis (M.S.)--Michigan State University. Agricultural, Food and Resource Economics - Master of Science, 2025Historically, farmers in the United States have relied on a flexible supply of low-wage labor from rural Mexico. Recent studies indicate there has been a decline in this labor pool, partly due to competition from other economic sectors. This study utilizes data from the National Agricultural Workers Survey (NAWS) to examine factors influencing crop farmworkers\u2019 likelihood of engaging in nonfarm work and whether such employment serves as a potential income-smoothing strategy for seasonal farmworkers. We define seasonal farmworkers as those who do not work for their farm employer on a year-round basis, which is about 54% of our sample. The NAWS samples current farmworkers, so our study is limited to those currently in agriculture and who may be splitting their time between farm and nonfarm work. One obvious limitation of using these data is the lack of information for those who completely leave agriculture to work in a nonfarm sector.We find that farmworkers who are male, have stronger nonfarm networks, higher education levels, legal work authorization, or engage in migrant farmwork (work done more than 75 miles from a worker\u2019s home) are potentially more likely to work off the farm. Additionally, nonfarm employment is associated with higher annual total earnings for seasonal farmworkers, which can indicate the role nonfarm work plays in stabilizing income. A forecasting exercise suggests that the proportion of farmworkers engaging in nonfarm work (in addition to farmwork) will increase to 33% in 2037, which is 4 percentage points higher than the estimate for 2027.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
MULTISCALE MODELING & OPTIMIZATION FOR LAMINATES FABRICATED WITH AUTOMATED FIBER PLACEMENT
No full textThesis (Ph.D.)--Michigan State University. Civil Engineering - Doctor of Philosophy, 2025Automated Fiber Placement (AFP) of fiber-reinforced thermoplastic tapes enables rapid manufacturing of structural parts by leveraging precise robotic fiber placement and in-situ consolidation. Accordingly, understanding the effect of processing parameters on resulting mechanical properties is essential. While experimental characterization of all possible structure-property relationships as a function of processing parameters is possible, it is infeasible due to the time and resources needed. Hence, predictive tools can provide valuable insight, enabling the widespread adoption of AFP-based manufacturing. This dissertation presents the development of a predictive model for the mechanical behavior of Carbon Fiber Reinforced Polyetherketoneketone (CF/PEKK) composites fabricated via Automated Fiber Placement (AFP), achieved through the establishment of analytical correlations between processing parameters and interlaminar bonding characteristics. The processing parameters that were investigated throughout the research effort include consolidation time, pressure, and temperature, either directly or inferred, using physical models that translate AFP processing parameters such as printing speed, heating power, machine and substrate geometry, and material physical properties. The dissertation includes three main areas of study, the first of which covers a wide range of experimental processes for material characterization. Mechanical, thermal, and microstructural testing were performed, which provided insight into the degree of sensitivity of the material to the different processing parameters and their effects on the interlaminar properties of the manufactured composite. The study indicated that material properties were most affected by processing time, which represented the key marker for the interlaminar chain diffusion that controlled interlaminar properties. The data was then used in the second study to modify an existing analytical model that predicts the level of bonding and was fit to our material properties and behavior. This study required the use of multi-physical modeling of material behavior using FEM and analytical tools to provide the underlying material properties and processing parameters that enabled the calibration of the modeling variables and material constants that were used for behavior prediction. Results indicate that our modified model can accurately capture the degree of bonding developed under both isothermal and non-isothermal consolidation conditions and relate it to matrix properties. These were subsequently used to accurately predict the composite behavior in the elastic zone as a function of in-plane shear behavior. For the third study we were able to predict the plastic behavior of CF/PEKK composites by applying a single-parameter analytical model, which was used to map the plastic behavior of lamina onto a yielding function for the laminate. This model was then used to inform material properties in plasticity, which was input into a microscale modeling FEM software to generate material properties in the meso and macro-scales, respectively. Material failure was then calculated through a combination of mechanical testing and crack surface area evolution prediction. This approach allows for simplified characterization of the tensile properties for CF/PEKK laminates with matrix-dominated behavior using in-plane shear testing from elasticity to plasticity and failure. A fourth study was launched and will be continued in future works on the joining of composites using AFP, where standard composite parts are joined at irregularly shaped junctions using the dexterity of AFP processing equipment. Initial experimental data show that AFP can be used for applications where stresses do not exceed yielding levels, given that beyond-yield damage can facilitate rapid crack growth which initiates at the discontinued junction.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Investigation of MicroRNA-10b as a Potential Target for Glioblastoma Nanotherapy
No full textThesis (Ph.D.)--Michigan State University. Biomedical Engineering - Doctor of Philosophy, 2025Glioblastoma is the most common and aggressive primary malignancy of the central nervous system with poor survival. Despite continued efforts, the development of therapeutics for glioblastoma is complicated by molecular heterogeneity and the presence of blood-brain barrier, which even in its disrupted form presents a challenge for drug delivery. Notably, microRNA-10b has recently been identified as a highly expressed biomarker in glioblastomas, a characteristic associated with tumorigenic pathways in metastatic cancers, whereas normal brain tissues are virtually devoid of microRNA-10b. The mounting body of evidence has shown that microRNA-10b is implicated in tumor cell invasion, migration, and, most importantly, viability. Inhibiting microRNA-10b with antisense oligonucleotides in glioblastoma cells disrupts various tumorigenesis pathways and ultimately results in cell death, revealing its importance for tumor cell survival. Delivery of naked oligonucleotides represents a challenge due to their inability to cross the cell membrane due to charge-charge repulsion, short half-life and digestion by nucleases, entrapment in endosomes, off-target effects, and activation of immune responses. To this end, we have developed a nanotherapy, termed MN-anti-miR10b, to ensure effective delivery of antisense microRNA-10b oligonucleotides to inhibit miR-10b and elicit cytotoxic effects in glioblastoma. MN-anti-miR10b consists of an iron oxide magnetic nanoparticle core covered with cross-linked dextran conjugated with Cy5.5 fluorophores and therapeutic anti-miR-10b locked-nucleic acid antagomirs. The superparamagnetic iron oxide core provides magnetic resonance imaging contrast while Cy5.5 is detectable by optical imaging modalities in vivo, thus enabling image guided therapy. The project described here begins with demonstrating in vitro that MN-anti-miR10b inhibits microRNA-10b, reduces migration and invasion, and induces cell death in glioblastoma cell lines. Following these studies, we show with multiple in vivo and ex vivo imaging modalities that MN-anti-miR10b is able to pass the disrupted blood-brain barrier and accumulate in the orthotopic glioblastoma tumor region. Ultimately, the studies culminate to show that MN-anti-miR10b and TTX-MC138, the commercialized and clinically tested analog, confer survival benefits in mice bearing orthotopic glioblastoma tumors. These studies demonstrate the efficacy of MN-anti-miR10b as a therapeutic against glioblastoma and make a case for the rapid translation for use in the clinic in GBM patients.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
PHYSICAL ATTACKS ON AUTONOMOUS VEHICLES IN SENSOR PERCEPTION AND CHARGING SYSTEM
No full textThesis (Ph.D.)--Michigan State University. Computer Science - Doctor of Philosophy, 2025Autonomous vehicles are reshaping modern transportation, aiming to improve safety, efficiency, and accessibility. Sensor perception plays a foundational role in autonomous driving and flying, providing the vehicle with a comprehensive understanding of its environment, which is essential for safe and efficient operation in dynamic, unpredictable surroundings. On the other hand, the charging protocol in autonomous vehicles manages critical interactions, such as energy transfer and system monitoring, to ensure the vehicle's safety, reliability, and overall operational integrity. However, in recent research on autonomous vehicles, security vulnerabilities in sensor perception and charging systems have emerged as significant concerns. To comprehensively understand the potential security threats to autonomous vehicles, this dissertation investigates physical attacks that disrupt either autonomous driving or battery charging operations by exploiting vulnerabilities in sensor perception systems and charging protocols. On the perception side, the work focuses primarily on depth estimation and object detection in both autonomous flying and driving scenarios, and introduces three distinct physical attacks targeting these components. On the charging side, the dissertation examines the electric vehicle charging protocol, presenting one physical-layer attack that manipulates the charging process through protocol-level vulnerabilities.First, this dissertation proposes doublestar, a novel attack on stereo depth estimation used for obstacle avoidance in autonomous vehicles and drones. By exploiting stereo matching weaknesses and optical lens flare effects, doublestar injects false depth perceptions using projected light sources, deceiving commercial stereo cameras and drones to cause sudden stops or erratic drifting. %, revealing critical flaws in stereo-based obstacle avoidance. Second, this dissertation introduces LensAttack, a physical attack using concave and convex lenses strategically placed on the vehicle's camera. By exploring the vulnerability of monocular depth estimation algorithms, LensAttack can manipulate depth perception to produce false object distances. It reduces the accuracy of monocular depth estimation significantly, raising concerns about the reliability of vision-based autonomous driving systems. Third, this dissertation presents an adversarial 3D projection attack on object detection in autonomous vehicles. By using dynamic color and geometric transformations on 3D surfaces, the attack can generate projectable adversarial patches on 3D objects to deceive object detection algorithms transiently and flexibly using projectors, potentially leading to traffic accidents. Fourth, this dissertation proposes ChargeX, which aims to manipulate the charging states or charging rates of electric vehicles to disrupt the normal charging schedules. By investigating the communication mechanisms between chargers and electric vehicles, the lack of protection for the authenticity in the SAE J1772 charging control protocol is exposed. ChargeX inserts a hardware attack circuit to strategically modify the charging control signals, causing denial of service or degradation of the battery performance.We have implemented and extensively evaluated the proposed doublestar, LensAttack, 3D projection attack, and ChargeX in both simulation and the physical world. These attacks were rigorously tested across diverse platforms and environments, including drones, self-driving cars, and electric vehicle charging infrastructures. The comprehensive evaluations validate not only the feasibility and practicality of each attack but also their potential impacts on safety-critical operations in autonomous vehicle systems.This dissertation concludes with an in-depth discussion of the limitations of current work and future research directions, highlighting both the challenges and opportunities in securing next-generation autonomous vehicle systems. These include exploring attacks and defenses that span multiple layers, from perception and sensor fusion to protocol validation and hardware-level protection, as well as understanding how the introduction of emerging technologies, such as foundation models, may open new attack surfaces or defense possibilities. By exposing underexplored physical vulnerabilities and developing effective attacks, this dissertation aims to provide not only a security warning but also a foundation for proactive defense design. The insights derived from these attack studies pave the way for future research toward building more robust, adaptive, and resilient autonomous vehicle systems.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Production of 49V, 73As, and 173Lu for Neutron-Induced Cross-Section Measurements
No full textThesis (Ph.D.)--Michigan State University. Chemistry - Doctor of Philosophy, 2025There is currently a deficiency in experimental neutron-induced cross-section measurements formany radionuclides, with theoretical predictions often exhibiting high uncertainties or considerable deviations from experimental data. Direct cross-section measurements could improve current nuclear databases. For instance, several radioisotopes of vanadium, arsenic, and lutetium were produced during underground nuclear tests, and while their transmutation properties are essential for interpreting the archival data, direct measurements of their neutron-reaction cross-sections have not been performed. To conduct these measurements, it is necessary to produce, purify, and fabricate suitable targets. Although production of many of the desired radionuclides is feasible, achieving the required quantity and isotopic purity can be challenging. This work explores the alternative production method of \u201cisotope harvesting\u201d to provide purified vanadium-49 (49V), arsenic-73 (73As), and lutetium-173 (173Lu) for target fabrication, all of which appear in important neutron- reaction networks from underground nuclear tests. Specifically, methods for solid-phase harvesting of 49V from proton- and deuteron-induced reactions for medical isotope production; solid-phase harvesting of 173Lu from a tungsten-alloy beam blocker from the recently decommissioned National Superconducting Cyclotron Laboratory; aqueous harvesting of 73As from a flowing water beam dump at its successor, the Facility for Rare Isotope Beams, will be discussedDescription based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Exploring Novel Quantum Materials Under Pressure
No full textThesis (Ph.D.)--Michigan State University. Chemistry - Doctor of Philosophy, 2025The pursuit of novel quantum materials lies at the forefront of condensed matter research, driven by the search for emergent phenomena such as unconventional superconductivity, topological phases, and exotic magnetism. Among the various tuning parameters, external pressure offers a clean and effective approach to explore uncharted regions of phase space by modulating interatomic distances, electronic bandwidths, and crystal symmetry, often stabilizing metastable or entirely new quantum states inaccessible at ambient conditions. This dissertation leverages high-pressure synthesis in combination with single crystal X-ray diffraction and detailed physical property measurements to discover and characterize previously unknown quantum materials with emergent electronic and magnetic behaviors. Key results include: (1) the synthesis of Ruddlesden\u2013Popper strontium iridates Srn+1IrnO3n+1, unveiling non-centrosymmetric Sr2IrO4 with spin-canted antiferromagnetism and a high-symmetry tetragonal SrIrO3; (2) the identification of a hidden polymorph and a pressure-induced structural transition in Ruddlesden\u2013Popper bilayer nickelate La3Ni2O7, offering insight into the structural landscape of nickelate superconductors. Collectively, these results underscore the power of high-pressure techniques in discovering new quantum materials and tuning their ground states through symmetry control and chemical bonding. This work lays the groundwork for future exploration of pressure-temperature phase diagrams and provides a framework for understanding structure-property relationships in strongly correlated systems.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Distilling Information from Simple Quantum Systems
No full textThesis (Ph.D.)--Michigan State University. Chemistry - Doctor of Philosophy, 2025This dissertation investigates the utility of simple quantum systems as powerful tools for understanding both quantum computation and molecular interactions. Just as fundamental units like the hydrogen atom provide foundational insight, these systems allow for the distillation of broader physical principles. This work studies two classes: entangled quantum states as probes for quantum devices, and small molecular complexes as models for intermolecular forces. The first part develops benchmarking frameworks based on maximally entangled Bell and Greenberger-Horne-Zeilinger (GHZ) states. By exploiting their intrinsic properties, protocols are constructed to extract detailed noise information, circumventing limitations of traditional methods as quantum processors scale. This includes entropy-based diagnostics that measure coherence loss and characterize noise structure from measurement distributions, entropy analysis of adiabatic GHZ state evolution to probe nonadiabatic transitions and entanglement development, and a polarization decay model for GHZ states under randomized perturbations, extracting error rates without classical overhead. These methods extend quantum benchmarking into regimes beyond classical simulation. The second part applies simple quantum systems to intermolecular interactions, relevant to molecular physics and planetary atmospheres. We compute the collision-induced dipole surface for the H2-H2 system to calculate its collision-induced absorption (CIA) spectrum, crucial for atmospheric modeling and telescopic interpretation. Subsequently, we investigate the unexpected nonideal mixing behavior of nonpolar methane (CH4) and tetrafluoromethane (CF4), elucidating how CF4\u2019s distinct electronic and vibrational properties contribute to this immiscibility. This analysis identifies microscopic mechanisms potentially generalizable to larger perfluorocarbon systems.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
ESSAYS ON THE EFFECTS OF PAY TRANSPARENCY
No full textThesis (Ph.D.)--Michigan State University. Economics - Doctor of Philosophy, 2025This dissertation evaluates the effects of Colorado\u2019s pay transparency law, which requires employers to add wage information in job postings. Chapter 1 examines how employers have responded to the law, while Chapter 2 evaluates its impact on labor market outcomes, paying special attention to gender differences. Chapter 3 studies the law\u2019s effect on job vacancy durations, exploring whether pay transparency influences the time required to fill positions.Chapter 1 of this dissertation analyzes employer responses to Colorado\u2019s pay transparency law. Using unique posting-level data sourced directly from employers, I provide descriptive evidence on wage posting behaviors before and after the law. I then employ a difference-in- differences design comparing Colorado to states that had previously enacted salary history bans but lacked wage disclosure mandates. Colorado\u2019s law substantially increased wage disclosure across occupations and firms, though compliance varied considerably. I find that the pay transparency law increased the fraction of job postings with salary information by more than 40 percentage points, though substantial noncompliance remains. Conditional on posting wages, I find a 3.4% increase in posted wages, driven mostly by higher upper bounds of wage ranges, which increased by 5.2%. However, these observed wage changes likely reflect compositional shifts in disclosed vacancies rather than direct changes in wage-setting practices. Overall, while Colorado\u2019s pay transparency law has significantly increased available wage information, the broader wage ranges highlight potential limitations in its informativeness.Chapter 2 of this dissertation evaluates the impact of the pay transparency law on labor outcomes. I use an equilibrium model with subjective beliefs to illustrate how wage beliefs affect job search behavior and outcomes. Under the assumptions that women have lower wage beliefs than comparable men and that more wage information in job postings reduces the gender gap in wage beliefs, the model predicts that the pay transparency law will decrease the gender wage gap. Using CPS data and a difference-in-differences design, I find that the law modestly reduced overall wages\u2014driven primarily by a decline in male wages among employer stayers. Consistent with the model, the gender wage gap narrowed sharply among employerchangers, falling from 17.5% to 3.5%. This decline was primarily driven by rising female wages; male wages also fell modestly, though the decline was not statistically significant. Despite a noticeable effect on the gender wage gap for job changers, pay transparency did not affect the gender gap in job mobility, employment, or labor force participation.Chapter 3 of this dissertation studies the effect on job vacancy durations. Using online job posting data and a difference-in-differences design, I find that the law had no effect on overall vacancy duration once firm and occupation fixed effects are included.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
PREVALENCE OF HEALTHY LIFESTYLE CHARACTERISTICS IN EARLY PREGNANCY : RESULTS FROM A PROSPECTIVE PREGNANCY COHORT IN MICHIGAN
No full textThesis (M.S.)--Michigan State University. Epidemiology - Master of Science, 2025Background: Public health guidelines and clinical recommendations emphasize the importance of healthy lifestyles during pregnancy for long-term maternal and child health, but healthy behaviors are inconsistently attained. Aim: To describe the prevalence of four healthy lifestyle characteristics (HLCs) among pregnant women in Michigan. Methods: Data is from a statewide prospective pregnancy cohort based on a stratified three-stage cluster sample design (hospital, prenatal clinic, and mother) recruiting participants from 23 prenatal clinics (n=1,228). This analysis includes self-reported survey data collected at participants\u2019 first prenatal care visit, whenever that occurred in their pregnancy, and birth certificate data. HLCs were defined as: healthy weight (pre-pregnancy body mass index of 18.5-24.9), nonsmoking (no cigarette smoking at the time of pregnancy determination, regardless of vaping or other substance use), adequate fruit and vegetable consumption (F&V; 65 5 servings/d), and regular physical activity (PA; 65 150 minutes moderate-to-vigorous physical activity/wk.). Prevalence and confidence intervals were calculated as a percentage \ub1 standard error of the study sample for each HLC. Results: Maternal characteristics included age: 18-<25 y (24.2%), 25-<30 y (30.8%), 30-<35 y (30.2%), 35+ y (14.7%); race: White (61.0%), Black (28.3%); ethnicity: Hispanic (4.2%); education: 64 high school (28.0%), some college (32.6%), 65 bachelor\u2019s degree (30.9%); employment status: full time (52.6%), part time (17.3), not working (21.7%); and income <25,000\u201375,000 (29.7%). Prevalence (95% confidence interval) of HLCs were: healthy weight, 33.9% (31.2\u201336.5%); non-smoking, 70.8% (68.2\u201373.3%); F&V, 11.4% (9.4\u201313.5%); and PA 33.9% (31.2 %\u201336.5%); all 4 HLCs, 3.6% (2.7-4.8%). Conclusion: Results indicate extremely low adherence to HLC recommendations among pregnant women in this statewide sample. Findings underscore the need for public health initiatives to create environments that support healthier lifestyles for most people.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references