Masters Theses

Permanent URI for this collection

https://hdl.handle.net/10919/9291

Browse

Now showing 1 - 20 of 23083

A Sense of the Tragic
Malik, Shaheer (Virginia Tech, 2025-05-20)
"A Sense of the Tragic" is a postcolonial novel written in the tradition of classical revenge tragedies such as The Oresteia and pre-modern English revenge tragedies such as The Spanish Tragedy and Hamlet. The narrative begins with a scene atop the World Trade Center the night before the terrorist attacks on 9/11/2001 and continues into the so-called 'War on Terror' with a post-colonial bent, exploring the struggles of the imperial periphery, the contradictions of the 'forever war' and the 'forgotten war,' as well as the various intersections of race, nationality, and other markers of identity as they pertain to the edges of contemporary empire. The story is narrated by an impish narrator named Revenge who prefers to relay the events of the story as if they are occurring on a television screen, mimicking both the 'image-event' and 'spectacle' quality of news coverage of terrorist attacks and the desensitized coverage of violence during 'forgotten wars.' By following the protagonist Zaid, a Pakistani boy who was born with the inexplicable desire to exact vengeance upon an enemy whose identity and location he does not know, the reader is encouraged to examine the nature of revenge and wars of revenge, as well as the aimless nature of the hate that so often fuels the desire for imperial adventures. The story also explores the themes of family, immigration and the Pakistani politics.
Silencing ITGB3 in Astrocytes
Lee, Jacob Harrison (Virginia Tech, 2025-05-19)
Investigating milk cell population changes in response to heat stress and characterizing functionality of epithelial cells in milk of lactating dairy cows
Cappellina, Anna Lofhjelm (Virginia Tech, 2025-05-20)
Understanding the number of mammary epithelial cells a cow maintains is essential to maximize milk synthesis in lactating dairy cows. This thesis aimed to investigate milk cell population changes in lactating dairy cows in response to heat stress (HS) using a pair-feeding model (PFTN). Additionally, this thesis explored the potential role of mammary epithelial cells in milk of lactating dairy cows as phagocytic cells capable of efferocytosing apoptotic mammary epithelial cells. The first study evaluated cell shedding into milk in response to nine days of HS or PFTN. There was a decline in dry matter intake (DMI) and milk yield (MY) in response to HS and pair-feeding. Milk yield decreased over 9 days for both treatments and PFTN cows had a greater MY on d 2,7, and 8 compared to HS cows. The concentration of MEC shed into milk did not change after nine days of HS or PFTN and there were no differences between groups. There was a lower concentration of immune cells in milk from HS cows and a higher concentration of BTN+CD45-CD14+ cells than PFTN cows. The second study examined the potential role of mammary epithelial cells as phagocytes in consuming apoptotic mammary epithelial cells during lactation. Mammary epithelial cells act as non-professional phagocytes during the dry period to aid in maintaining tissue homeostasis. The role of mammary epithelial cells as phagocytes during lactation in dairy cows hasn't received investigation. In this study, mammary epithelial cells in milk consumed cultured apoptotic mammary epithelial cells under in vitro conditions. Factors that influence mammary epithelial cell shedding into milk play an important role in milk production. By investigating factors that affect cell shedding into milk we can better understand the dynamics of the mammary gland and potentially improve milk production and lactation persistency in cows.
Lunar Surface Navigation Using Gravity and Star Tracker Measurements
Taylor II, Thomas Jennings (Virginia Tech, 2025-05-20)
This thesis develops and analyzes a method that uses measured gravity and starlight vectors to provide position and attitude estimates, given a predefined high-fidelity lunar gravity field. The gravity field uses provided values for the surface gravity magnitude and the East-West (EW) and North-South (NS) deflections of the gravity vector across the lunar surface. These gravity measurements are location-specific and are shown to be influenced by nearby craters and other topographic features. Gravity is more concentrated in these regions, causing the gravity vector to deflect in their direction. The gravity field used in this study (Lunar Gravity Model 2011 (LGM2011)) was developed specifically for surface use, resulting in more accurate gravity measurements compared to other models calculated using spherical harmonic expansions. Future lunar missions prompt the need for new surface navigation techniques. Current position and orientation (POSE) methods employ star trackers (ST) and accelerometers but do not incorporate the use of an external gravity field. The Multiplicative Extended Kalman Filter (MEKF) developed in this study uses these sensors and their data to define a state consisting of the attitude error vector, a, between the estimated quaternion—found using Shuster's Quaternion Estimator (QUEST) algorithm—and the reference quaternion, the longitude (λ) and latitude (ϕ) positions, and the dynamic accelerometer bias. The MEKF assumes constant state propagation between time steps and a covariance update influenced solely by the Moon's rotation. It also assumes that the reference gravity field is perfectly accurate. However, this assumption introduces inaccuracies in the position estimates due to discrepancies between the true measured gravity and the gravity predicted by the model. These biased position estimates, along with a known accurate reference position, are then used to solve for the correlated gravity bias in the lunar gravity field at various waypoints during a surface mission. As a test case, the reference position is determined using two-way ranging measurements between the ground system and the Lunar Pathfinder satellite. These measurements are processed through a combined weighted batch-to-EKF filter to produce the reference position. A least-squares cost function is then formulated using the MEKF outputs and reference positions to estimate biases in the gravity field. The gravity bias algorithms presented are demonstrated to enable successful surface navigation for a roving mission on the lunar surface.
"Trust Deficit Disorder": The Role of Social or Economic Grievances on Institutional Trust During Covid-19 in the United States
Lamkin, Raegan Elizabeth (Virginia Tech, 2025-05-20)
Trust in institutions across Western countries has been on the decline for some time now. World events, such as the Covid-19 pandemic, had an impact on trust. Secretary-General Antonio Guterres (2018) titled this decline across countries a "Trust Deficit Disorder". A great deal of scholarship has contributed to ideas on why trust is important to a state. On the other hand, there is less understanding of how trust declines and what factors contribute to the decline. The Covid-19 pandemic, and the social restrictions and economic decline that followed, had a great impact on trust in American institutions. This thesis examines both the grievance hypothesis and the macro-institutional hypothesis as it relates to the decline of trust in American institutions, specifically the White House, Congress, state government, and city government, during the Covid-19 pandemic. Utilizing Collier and Hoeffler's (2000) grievances, I approach the perceptions of social restrictions and economic decline from the Covid-19 pandemic as grievances. Additionally, following the framework of Hardin (1993), trust is defined as "a three-part relation: A trusts B to do X" (pg. 506). By employing concepts by Collier and Hoeffler (2000) and Hardin (1993) and drawing from the framework of Mishler and Rose (2001), this thesis seeks to understand if there is a relationship between economic or social grievances and institutional trust. Three hypotheses are being tested including Hypothesis 1: States with stricter Covid-19 measures will have lower trust in institutions than states with less strict Covid-19 measures, Hypothesis 2: States with a greater negative change in employment rate will have lower trust in institutions than states with greater positive change in employment rate, and Hypothesis 3: States with a greater positive change in quarterly GDP will have lower trust in institutions than states with no change in quarterly GDP. To test the hypotheses, in a state-level analysis, this thesis uses a regression-based approach with survey data collected from the Covid States Project alongside social and economic data from other official sources. Overall, there is little evidence to support the hypotheses that economic or social grievances affect trust in various institutions. Although the relationship between no trust in the White House and Covid-19 policies is shown to be statistically significant, the models show a negative relationship. Therefore, when states have more Covid-19 policies there is a decline in survey respondents who do not trust the state government. There is some evidence to support that different institutions react differently to each grievance. Future research should consider the impact of social identities, the definition of trust by survey respondents, the differences in trust in various institutions, and the suitability of an analysis at the individual level.
General Sir Richard O'Connor, a profile of his life and career
Startup, Kenneth Moore (Virginia Tech, 1977-11)
In 1940, General Sir Richard O'Connor, with two divisions under his command, initiated a campaign in north Africa which resulted in the destruction of the Italian Tenth Army and the conquest of Cyrenaica. O'Connor's success freed Egypt from the threat of an Italian invasion. In addition to these tangible results, O'Connor's desert campaign was a serious blow to Mussolini's prestige, both in Italy and throughout the world. The campaign was brilliantly planned and directed; it has few parallels in military history. Not surprisingly, a great deal has been written about O'Connor's African victory; O'Connor himself, however, has remained strangely obscure. Indeed, virtually nothing of his "pre" and "post" desert career can be found in print. It is hoped that this thesis, which is largely based upon O'Connor's own recollections, will present the reader with a clear and balanced portrait of the General's remarkable life and career.
Understanding the Impact of ACL Reconstruction on Normalization Methods and Identifying Predictive Factors of Landing Symmetry
Weiss, Samantha Inge (Virginia Tech, 2025-05-19)
ACL injuries are one of the most common knee injuries1–4, occurring in 1 out of every 3500 individuals in the Unites States5. Over 200,000 ACL reconstruction surgeries occur each year2,6–9. Following a primary ACL tear, the likelihood of experiencing a second tear increases to 10-25%3,10–15. This rate of reinjury can fluctuate based on activity level3,10,16–18. Athletes returning to sports, specifically, have higher retear rates16,17. Load symmetry has been used to assess performance and risk in patients with ACL reconstruction (ACLR)19–22. While there are ample amounts of research investigating this injury, there are gaps within the literature that need to be addressed to continue to better understand ACL injuries. When analyzing data from patients with ACLR, there are common assumptions used by many different scientists that may influence the way data can be interpreted23. Additionally, previous literature has identified influences of psychological components on injury risk of a primary ACL injury and throughout rehabilitation24–27, but there is minimal knowledge on how these components can be used to predict second ACL risk factors. Therefore, the purpose of this study was to investigate the assumptions made when data is being analyzed for this clinical population, and if psychological components can be used to predict risk factors for a second ACL injury. The common data analysis assumption tested in this study was percent stance normalization because this method has not been validated to produce accurate data in patients with ACLR. Percent stance was then compared to a time independent method. In a cohort of healthy controls and patients with ACLR, using symmetry to assess loading differences, there were differences found in symmetry metrics commonly used to assess performance, including peak impact force (PIF), loading rate, impulse, and time to peak. These results show a need to revisit common assumptions used to analyze data when including patients with ACLR. Future studies could conduct a similar analysis in different clinical populations. Following this analysis, psychological components, ACL-RSI, M-LOC, and GAD-7 surveys, and physical factors were combined in a regression model to predict landing symmetry. In both unilateral and bilateral landings load asymmetry has been identified as a risk factor for reinjury28. Backwards multivariate regression models were created for three unilateral and two bilateral landing tasks. Each model included both one or more psychological components and previously identified risk factors in the final factors to best predict PIF. However, the only models that could explain an adequate amount of variance were the unilateral landing models (single hop R2= .351, triple hop R2= .423). These models show the importance of including psychological components and previously researched risk factors to best understand reinjury risk in patients with ACLR. The results from this study indicate ways to potentially improve analysis of patients with ACLR. When investigating this population, testing common assumptions made for healthy controls and inclusion of psychological components when assessing performance may improve interpretation and can help clinicians better identify risk for patients with ACLR.
Digital Storybooks to Teach Children Computer Science and Address Common Misconceptions
Deverin, Thomas Stefan (Virginia Tech, 2025-05-19)
CodeKids is a web-based platform developed to teach computational concepts to elementary and middle school-aged children. The platform hosts many interactive digital books that teach various computational concepts from bits and bytes to artificial intelligence using themes that children can easily relate to. This study focuses on books created to address common misconceptions students form when learning foundational computer science concepts including variables, conditions, and loops. The primary objectives of this research are to evaluate the students' perceptions of the digital storybook format and compare the misconception rates of students who used the storybooks to those from previous studies. A study was conducted at a local middle school with 6th and 7th-grade students who used two of the books created to target common variable misconceptions. Results revealed that students believed the books were engaging, and their self-perceived knowledge of variables increased after using the books. However, misconception rates remained comparable to prior research, highlighting the challenges in addressing misconceptions. Additionally, when students were asked to rank their prior programming language experience and programming environments they have used, it was found that the students' computer science knowledge is behind the regional educational standards, emphasizing the need for educational material like CodeKids to teach computer science to young students. The findings suggest that while the storybook format used by CodeKids is a promising medium to teach children computer science, more research needs to be done to refine the design and develop tools that effectively address misconceptions.
Building a Reservoir
Gaynor, Grace Anita (Virginia Tech, 2025-05-19)
Building a Reservoir is a collection of poems and stories that meditate on the ways we congregate around, connect with, rely upon, enjoy, misunderstand, misuse, and mythicize water. Throughout the collection, water allows for reflection, scrutinization, and meaning-making and acts as a mirror, magnifier, and mystifier. At its core, Building a Reservoir is about bodies, as we are almost always talking about bodies when we talk about water. The project utilizes images of and interactions with the ocean, lakes, pools, fish tanks, and other bodies of water to enter into conversations about religion, sexuality, race, gender roles and expectations, trauma, resources, consent, and commodification.
Spatiotemporal Variation in Dispersal as a Driver of Macroinvertebrate Metacommunity Dynamics
Bush, Brian (Virginia Tech, 2025-05-19)
Across taxa, community assembly has traditionally been attributed to local processes such as species competition and environmental filtering. Metacommunity theory, however, highlights regional drivers such as dispersal and connectivity as key structuring forces. The mechanisms governing freshwater macroinvertebrates community assemblage have long been studied due these organism's ubiquity, diversity, and sensitivity to environmental stressors. Macroinvertebrates reliance on river networks for their larval stages also makes their dispersal complex, and therefore crucial to frame their assemblages in a metacommunity context. While metacommunity theory has been widely applied to macroinvertebrate community ecology within the last 15 years, the spatial and temporal variability of dispersal across networks is still poorly understood. To address this gap, we conducted a year-long survey of the macroinvertebrate communities in the Little Stoney Creek watershed of Giles County, Virginia. Macroinvertebrates were sampled once a month for 12 months from the benthos and drift at eight sites across a gradient from headwaters to mainstem to discover if there was any difference in community dynamics between poorly connected sites (headwaters) and well connected sites (mainstems) across seasons. Broadly, we hypothesized that mainstem sites would have less temporal variability in community dynamics compared to headwater sites due to mass effects and high dispersal rates. We found high temporal variability in dispersal and the subsequent correlation of dispersal assemblages with the resident benthic community across sites, but only weak evidence to suggest that this variation varies between headwaters and mainstems. However, considering the stochastic and difficult to model nature of macroinvertebrate drift dispersal, we consider the existence of even weak evidence of spatial differences to be promising. Further study of macroinvertebrate dispersal in metacommunities is needed to better understand the complex mechanisms governing macroinvertebrate communities, particularly in the context of biomonitoring applications.
Understanding Russian Hybrid Warfare: A Comparative Case Study Analysis of Soviet Active Measures and Russian New Generation Warfare
Luppino, Patrick Joseph (Virginia Tech, 2025-05-19)
Russian Hybrid Warfare is a popular Western term for contemporary Kremlin operations that directly target adversaries without conventional force. Often described as the mistaken "Gerasimov Doctrine" or "New Generation Warfare," Russian Hybrid Warfare operations utilize unconventional tactics to achieve grand strategy objectives in domains where the Kremlin believes it has advantages over Western forces, such as through informational and digital battlespaces. International relations and national security scholars acknowledge these operations as a revolutionary and new way of conducting warfare by the Russians, attempting to invent analyses to examine the Kremlin's strategies. I argue that this is unnecessary, and scholars should employ currently neglected analyses and Soviet tactics from the Cold War era. In attempting to answer the question, "How do Soviet strategies in asymmetric and political warfare compare to contemporary Russian counterparts?" I hypothesize that Russia's new way of warfare, or New Generation Warfare, is revisioned Active Measures tactics from the Soviet era for use in the twenty-first century's conventional battlespaces. Utilizing covert action, psychological operations, sabotage, espionage, and other unconventional tactics used by Soviet intelligence agencies, the Kremlin deploys comparable strategies for directly targeting its adversaries in the twenty-first century without requiring conventional forces, but implements the stages that allow a conventional deployment. This research intends to answer this question through a comparative case study analysis of Soviet active measures and Russian New Generation Warfare using historical cases where unconventional-to-conventional operations occurred. These case studies include the Warsaw Pact invasion of Czechoslovakia in 1968 and the Soviet invasion of Afghanistan in 1979 for analyzing active measures and the invasions of Ukraine in 2014 and 2022 for New Generation Warfare. Consequently, this research fills many gaps in the current Russian Hybrid Warfare discourse by including neglected Soviet active measures strategies and military thought, ending the argument that the Kremlin developed a new way of warfare and allowing Western states to accurately deploy defenses for countering future operations.
Hail to the War Princess: Security Crisis and Gendered Dynamics of Executive Leadership in Central and Eastern Europe
Roe, Elena Grace (Virginia Tech, 2025-05-19)
In 15 nations within the Central and Eastern European (CEE) region, at least one woman has risen to the apex of domestic political power through her election to one of these dual executive positions. The pertinence of war in Europe, however, raises immediate questions as to the context within which these women govern. Previous literature indicates that constituents find male government officials to be more competent when dealing with issues of security (Lawless, 2004; Kang and Kim, 2020), while populations often prefer men's leadership during crisis, aligning the traditional traits of leadership with masculinity (Kang and Kim, 2020). Given the rise, stagnation, and eventual exponential escalation of security crisis in Central and Eastern Europe over the last decade, how do women executives approach highly masculinized crises so as to avoid political disadvantage relative to their male counterparts? I argue that high levels of NATO cohesion in the region have led to a security policy consensus, which minimizes gendered pressures on women executives during security crisis through a universally accepted set of policy prescriptions. I utilize a mixed methods approach, combining OLS regression analysis and short case studies to examine the policies and political outcomes of women leaders during the Russian invasion of Crimea and full-scale invasion of Ukraine. I find evidence that women leaders experience better political outcomes when they advance pro-NATO policy positions in countries where there is a security consensus, but face criticism and political punishment where either of these conditions is not met.
Development of a test method for evaluating safety helmets' ability to reduce skull fracture and brain injury risk from falls in construction
Gagliardi, Susanna Maria (Virginia Tech, 2025-05-19)
Falls in the construction industry account for the greatest number of fatal and non-fatal traumatic brain injuries (TBIs), however current safety helmet standards do not test safety helmets under impact conditions realistic to this injury event. Safety helmets are broadly classified into two groups: Type I, which are tested at the top of the helmet and Type II, which are tested to the top and side of the helmet. However, even the more protective Type II helmets are not tested at energy levels high enough to be representative of falls, which can occur from a wide range of heights. To evaluate the protective capacity of safety helmets, realistic impact conditions need to be identified to accurately recreate fall events in a laboratory setting. However, this remains a challenge as there are limited studies or videos evaluating head impact boundary conditions during falls in construction. The research presented in this thesis had three primary objectives: to determine the head impact velocities associated with falls from various heights while accounting for reductions in energy due to fall impact mitigating mechanisms; to identify the necessary boundary conditions such as impact surface, impact angle, and impact locations needed to recreate various fall events; to develop and execute a testing methodology that accounts for the previously outlined boundary conditions, and evaluates safety helmets' ability to reduce brain injury and skull fracture risk. The results show that fall-arrest movements associated with bracing can lower the head impact severity from a fall, providing insights into appropriate head impact velocities for safety helmet testing. Through analyzing fall accident reports, performing exploratory oblique helmet testing, and examining previous literature, boundary conditions for recreating falls in a laboratory setting were established. This information was then used to develop and execute a safety helmet testing methodology that evaluates safety helmets for protection against concussion and skull fracture risk. The results of this study demonstrated a wide range of performance across Type I and Type II helmets. Type II helmets were more effective at preventing skull fracture, emphasizing the benefits and reductions in catastrophic head injury risk when wearing a Type II safety helmet for protection against fall scenarios.
These Are The Rules
Santana, Catalina Enith (Virginia Tech, 2025-05-19)
These Are The Rules is a novel-in progress that follows the lives of Emmanuelle, sole prisoner on a spaceship, and Hector, the advanced artificial intelligence that runs the ship and looks after Emmanuelle. In addition to the overarching plot on the ship, the novel includes scenes from Emmanuelle's life on Earth, as well as moments from Hector's first days of existence. The work also incorporates scenes that reimagine traditional Latin American folklore and colonial history with moments written from the point of view of inanimate objects. Existing within the literary speculative fiction and magical realism genres, the narrative's eclectic framework and use of language combines prose and poetry and the inorganic with the organic, to emphasize the miraculous interlocking combination of details that build up to an individual identity. The chapters also explore betrayal and martyrdom; love and memory; power and helplessness; abandonment and tragic lingering. It asks: How did my ghosts and I arrive here?
Spiralism in Haitian Literature: the Chaos-Creation Cycle
Ingram, Tamara Knapp (Virginia Tech, 2025-05-19)
Spiralism is a literary, philosophical and artistic movement born in Haiti in the late 1960s under the oppressive regime of François Duvalier. This movement captures life in chaos and suggests a non-linear understanding of time and experiences. Embracing a fluid and interconnected perspective on existence and art, Spiralism expresses outrage at governmental tyranny and offers an unconventional narrative style that emphasizes the recurring cycles of time and experiences and repeating characters. Haitian writers have historically faced significant barriers to publication, which has contributed to the marginalization of Haitian literature in academic discourse. This thesis explores why and to what extent Haitian literature has been marginalized, beginning with an overview of the country's history in order to create the foundation for exploring Spiralism and Frankétienne, the most prominent of the movement's founders. It includes an analysis of Mûr à crever, considered the quasi-manifesto of Spiralism, and examines Frankétienne's literary techniques that intertwine chaos and creation and challenge the linear concepts of time and space. The final section of this thesis explores the enduring influence of Spiralism in contemporary Haitian literature. Through an analysis of two of Emmelie Prophète's novels, this thesis argues that Spiralism continues to resonate in today's works in the themes of exile, liminality and fragmentation. The spiral represents the cycling challenges of the Haitian people and the gradual but inevitable movement forward, reflecting their resilience, adaptability and enduring hope.
The influences of hydrology and vegetation on emergent insect and benthic macroinvertebrate communities across space and time in seasonally inundated, geographically isolated wetlands
Sicking, Elizabeth Anne (Virginia Tech, 2025-05-19)
Geographically isolated wetlands are vulnerable to both land use and climate change because they are typically small, and are embedded in uplands. However, they support a diverse community of aquatic macroinvertebrates, including insects that serve as energy in upland food webs when they emerge as adults. How aquatic macroinvertebrate communities, particularly emergent aquatic insects, respond to vegetation and differences in long-term patterns of water permanency in isolated wetlands is unknown. To understand the influences of vegetation type and historical hydrology in isolated wetlands, we investigated benthic and emergent macroinvertebrate community characteristics from February - early August 2023 in five swamps and six marshes. We hypothesized that macroinvertebrate communities would reflect adaptation to both hydrology and vegetation communities through their richness and biomass, with long hydroperiod sites and marshes having the greatest richness and biomass of both benthic macroinvertebrates and emergent aquatic insects. We found that both hydroperiod length and vegetation type were important predictors of some but not all of our community characteristics. Benthic macroinvertebrate richness and biomass were greater in marshes than in swamps and influenced by both hydrology and vegetation, while emergent insect richness and biomass flux were most influenced by hydrology and greatest in long hydroperiod wetlands. Community composition was not predictable based on either hydrology or vegetation alone, but combined they explained around a third of the variation in community composition. Our results indicate that insects and non-insect macroinvertebrates with faster life cycles were more common in short hydroperiod sites and swamps, and longer-lived aerial insects were more common and diverse in long hydroperiod marshes. Predicted shorter hydroperiods will likely reduce biodiversity and insect biomass exported to the surrounding landscape, an important subsidy that supports terrestrial food webs. The export of material from aquatic to terrestrial systems is not often considered in conservation planning, but may occur during critical periods for terrestrial species, making the conservation of GIWs increasingly important.
Safety First, Bubbles Second: Integrating Regulatory Compliance with Innovation in Rapid Prototyped Focused Ultrasound Devices
Huynh, Laura (Virginia Tech, 2025-05-19)
Focused ultrasound (FUS) devices are being developed for noninvasive treatment across a range of clinical applications. High-intensity methods, such as histotripsy, introduce safety and performance considerations that may arise during early stages of prototyping. This thesis presents an evaluation framework intended to support early-stage identification of factors related to clinical and regulatory requirements. The framework was developed using risk management principles to identify risks during prototyping and determine which may be addressed through design modifications for the specific application. For risks not fully mitigated through design, the research focused on three safety domains: biological compatibility (ISO 10993), electrical safety (IEC 60601-1), and acoustic characterization (IEC 62127-1). The framework was applied to a case study involving 3D-printed materials commonly used in rapid prototyping for FUS research, assessing performance according to established guidance documents and international standards. In this context, materials with favorable acoustic performance did not consistently meet biocompatibility criteria, and electrical safety issues were only identifiable through specific testing that might otherwise be overlooked in early development phases. These findings highlight the role of concurrent safety evaluation across multiple areas. Structured assessments during early development produced data aligned with regulatory expectations and identified factors that may influence later design stages. The framework may be applied to full-system prototypes and explored further across various FUS device types.
Frequency Interception and Manipulation Vulnerabilities in Myoelectric-Computer Interface Signal Transmission
Szczesniak, Emma Victoria (Virginia Tech, 2025-05-19)
Neural interface systems such as myoelectric-computer interfaces (MCIs) and brain-computer interfaces (BCIs) assist patients with motor impairments due to injury or neurodegenerative conditions. Neural interface research has focused on device accuracy and usability while neglecting to comprehensively assess security risks. These devices store substantial personal data that can lead to exploitation if compromised. Attacks can override user intent, having major implications on a user's physical safety and psychological well-being. As neural interfaces become more prevalent, understanding and addressing their vulnerabilities is imperative to ensure user safety and data privacy. This study aimed to identify distinct frequency characteristics between upper limb motor tasks and examine data transmission frequencies to assess potential vulnerabilities in MCI systems. The HackRF One identified three distinct frequencies involved in the frequency hopping pattern during signal transmission, which allows attackers to intercept EMG data. Surface electromyography (sEMG) data produced by wrist flexion and extension motor tasks were analyzed in the frequency domain and showed statistically significant differences in frequency metrics. Distinguishing frequency metrics enable manipulation of motor commands in MCI systems by sending false signals at specific frequencies. This work provides insight into vulnerabilities in the signal transmission stage of neural interfaces to encourage developers to safeguard against potential attacks and to inform consumers of the security risks associated with these devices and their impact on user safety and protection of neural data.
Re-Envisioning the United States' Search for Re-Empowerment after 9/11: Vulnerability, Visual Framing, and Violence
Mennitt, Elizabeth Anne (Virginia Tech, 2025-05-19)
This thesis analyzes the relationship among vulnerability, violence, and the framing of images right after the 9/11 attacks and throughout the subsequent war on terror. It examines eight prominent images circulated in the United States at that time. The thesis argues that the revelation of US vulnerability on 9/11 was not merely suppressed or denied by the US state, but instead was strategically mobilized to (re)construct a dominant framing that could justify the US violent conduct of its operations in Afghanistan and Iraq. In part, this was done to reassert the United States' identity as a hyper-powerful and masculine power. Drawing from the work of critical political and international relations theorists like Judith Butler, Giorgio Agamben, Cynthia Weber, Tim Luke, and others, I show how the visual framing of the eight images selected in this study helped to produce, but also sometimes to destabilize, the social and political conditions that enabled certain, often "othered," bodies to be relegated to what I call "zones of endemic precarity" —that is to say, spaces where suffering was permissible and ongoing, yet often unaddressed or unrecognized by the US public and the US government. I emphasize the differential experience and representation vis-à-vis vulnerability as the United States and "othered" bodies during the war on terror generally do not experience violence and vulnerability in the same way. This study ultimately finds that the violence undertaken by the US during the war on terror—in part, as a response to the violence the US experienced on 9/11— does not manage to fully re-empower (or re-masculinize) the US and does not remove the vulnerability that was first represented in images right after the 9/11 attacks. I conclude the study by calling for a more critical approach to viewing violent images so that we may be better able to resist the power-infused visual frames through which such images (and their meanings) are often understood. This thesis contributes to critical IR scholarship on visual politics and contemporary violence by demonstrating how visual media frame, construct, reproduce, or render invisible many of the vulnerable subjects of global politics.
Parameter Estimation for Delay Differential Equations: A New Galerkin Approximation Framework
Hartman, Jonathan Cole (Virginia Tech, 2025-05-19)
Delay differential equations with discrete and/or distributed delays are widely used in many applied fields, including mathematical biology, climate science, and engineering. These equations contain free parameters and integral kernels that must be optimized to fit the dynamics of the physical systems they model. In this thesis, we present a framework for determining the discrete delays, integral kernels, and other unknown model parameters for these equations from training data through a Galerkin approximation approach proposed by citet{CGLW16}. The adopted Galerkin approximation is based on a particular type of polynomials due to T. H. Koornwinder, which are orthogonal under an inner product with a point mass cite{Koo84}. Within this Galerkin framework, the parameter estimation problem is reduced to the estimation of some scalar parameters in the resulting ordinary differential equations. Thanks to the analytical nature of the Galerkin approximation, the latter estimation problem can be handled efficiently, even with distributed delays, which is a known computationally challenging scenario. In all the cases, the system's dependence on the delay parameters is nonlinear. We will show how the training data and the Galerkin systems can be suitably adapted to efficiently convert this nonlinear estimation problem into successive linear estimation problems. The approach will be illustrated on concrete examples arising from various applications that exhibit either periodic or chaotic dynamics.

Browse

Recent Submissions