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Open-Source Hearing Aids: A Look into the Future of Medical Technology and Coding
No full textHearing loss affects a large portion of the global population, yet the prices for hearings aids continue to increase. With quality devices costing an upwards of 100 and more, depending on the manufacturer. However, people with mild to severe hearing loss would not be able to use such devices [2]. Open-source hearing aids could be an effective alternative to current FDA-approved hearing aids. Open-source hearing aids not only offer a more affordable alternative but also allow patients to customize and create their own unique devices. This may include adjustable sound profiles, specific molding to the ear, aesthetic modifications, etc. This blog post aims to discuss open-source hearing aids, their pros and cons, and how they can be used in the future for the advancement of technology in medicine. With the new technological advancements and developments in Artificial Intelligence (AI), the idea of patients being involved with creating their own devices may lead to a better and more inexpensive direction for the healthcare field.Published versio
Maintaining Nuclear Stability in the Wake of a Strained Liberal Order
No full textThe liberal order that has defined the last eighty years of history is undergoing a major shift. The United States has long been the tradition-maker of the order, and the consensus leader since the end of the Cold War. This, however, is changing as American domestic policy turns inward and has lost the domestic reliability that allowed the current order to blossom. The nuclear nonproliferation regime coevolved with the liberal order, and as the order moves away from American hegemony, the nonproliferation regime, as an institution of the liberal order, is also evolving. Unlike other institutions that may decline or disappear as multipolarity emerges, certain aspects of the nuclear nonproliferation regime must remain. To do this, nuclear states should continue to encourage an environment of nonproliferation by providing a reinforced security umbrella and supporting state access to peaceful nuclear energy programs. Additionally, current global leaders should reinforce commitments to non-first-use policies that prevent the need for others to obtain second-strike capabilities. These principles, which are essential to the existence of the nuclear nonproliferation regime and have underpinned the success of the liberal order, much remain intact as the world shifts into an era of increasing multipolarity.Master of ArtsThe world has experienced zero nuclear incidents since the United States detonated two nuclear bombs in Japan at the end of World War II. This peace has been largely due to the rules that have guided states with nuclear weapons and certain principles that most nuclear states follow. These rules have been developed as a part of the broader international order, led by the United States, and exist in support of how states function within the global system. This system, however, is shifting away from the United States' leadership, and questions remain about how nuclear stability will look in the future. In order to maintain nuclear peace, policy should focus on preventing the spread of nuclear weapons and limiting the reasons for new states to seek the protection of nuclear weapons
Towards Human-AI Teaming for Skill Development: From Dyadic Interview Practice to Triadic Programming Collaboration
No full textAs the job market for CS graduates grows increasingly competitive, effective preparation for technical interviews through mock interviews and programming practice has become critical. This thesis explores how AI can support skill development in these domains, progressing from AI as a sole practice partner to AI as a collaborative teammate. Our first two studies investigate LLM-based conversational AI for interview preparation. Study 1 developed an interview system grounded in reflective learning and dialogic feedback, enabling learners to engage in low-stakes practice with personalized, interactive feedback. Study 2 extended this work to technical interviews, exploring how conversational AI can support the think-aloud practice in technical interviews through simulation, feedback, and example. Together, these studies demonstrate the value of AI as a dyadic practice partner. However, participants reported that while AI practice was useful, peer-based engagement may offer stronger social connection and motivation, suggesting that AI should augment rather than replace human collaboration. This insight motivated our third study, which investigates human–AI teaming in a triadic configuration. We introduce human–human–AI triadic programming, where two humans collaborate with a proactive AI agent. Results from 20 participants show that this triadic collaboration improves collaborative learning and social presence while encouraging more responsible AI use. Together, these studies advance understanding of how AI can support skill development, illustrating a trajectory from dyadic human–AI interaction toward richer forms of human–AI teaming that preserve the pedagogical and social benefits of human collaboration.Master of ScienceAs the job market for computer science (CS) graduates becomes increasingly competitive, developing technical and communication skills is essential. Artificial intelligence (AI), particularly large language models (LLMs), offers a promising way to support this process. Yet little is known about how users perceive LLM-based interview practice support or what design considerations should guide their development. Therefore, our first study developed an LLM-based interview practice system grounded in reflective learning and dialogic feedback, followed by exploratory user studies. Our second study extended this work by exploring how conversational AI can support technical interview preparation through technical interview simulation, feedback, and examples. Together, these studies demonstrate the potential of conversational AI as a partner for interview preparation, enabling low-stakes practice with personalized feedback. However, our users also expressed a preference for practicing with peers, which potentially provides a better learning experience. Hence, this raises a question: rather than replacing human partners, can AI augment a peer-based practice while preserving the social and pedagogical benefits of collaboration? This question motivated our exploration of human–AI teaming, where AI is treated as a teammate and interactions can extend beyond dyadic settings. Building on this insight, our third study investigated human–human–AI triadic programming, where two humans collaborate with a proactive AI agent. Results from 20 participants show that this triadic collaboration improves collaborative learning and social presence, while encouraging more responsible AI use
Insects
No full textClassical biological control of exotic invasive weeds first took place in India in 1795. Thus far, a total of 174 natural enemies have been imported into India, and out of these, 77 have established themselves in the field. Twelve exotic insect pests and four weeds were successfully controlled with a combination of classical, augmentative, and conservation biological control. Additionally, eight insect pests and one weed were substantially controlled. Augmentative biological control has been adopted as per the needs and availability of resources. Conservation biological control is ubiquitous and has been facilitated by the adoption of integrated pest management. In the past, biological control activities were sporadic; however, since 1977, the Indian Council of Agricultural Research—National Bureau for Agricultural Insect Resources has been regularly implementing classical biological control of invasive agricultural insect pests of economic importance. Unfortunately, the importance given to invasive weeds and insect pests of natural resources has fallen behind in recent years.Published versio
HUD-VASH Efficiency and Effectiveness: Homelessness and Veterans' Housing Policy
No full textThe research explores why federal funding targeted for vouchers for homeless veterans in the HUD-Veterans Affairs Supportive Housing program (HUD-VASH) declined between 2009 and 2024. It compares funding for the expansion of the veteran homelessness program and the use of that funding for housing vouchers before and after implementation of Housing First in the Ending Veteran Homelessness Initiative. The study employs an exploratory, mixed quantitative and qualitative analysis. As coalitions to address homelessness among military veterans formed after HUD-VASH was authorized, different narratives about the causes of and possible remedies to veterans' underutilization of housing vouchers emerged as vehicles for policy entrepreneurs to promote different means for achieving the same ends for homeless veterans. Melding the Jenkins-Smith/Sabatier advocacy coalitions perspective with narrative, punctuated equilibrium, and multiple stream theories, the research highlights that limiting the program's funding evidently had little to do with its effectiveness at reducing homelessness. Instead, program efficiency and policy efficacy became the focus as coalition advocacy for implementation spanned partisan and ideological divides.
Program efficiency, not effectiveness, emerged as the problem that policy entrepreneurs focused upon, building coalitions around opposing narratives of fiscal stewardship of U.S. taxpayer dollars. Over time, HUD-VASH effectiveness flourished, but funding increasingly languished under advocacy coalitions' control of congressional committees. These coalitions' identification of the Housing First policy strategy as the pre-eminent "cause" of and "cure" for the underutilization of vouchers became a point of contention, limiting growth.
In the absence of systematic analysis by the VA of the efficiencies of HUD-VASH or its underwritten policies, a pro-Housing First Coalition formed around international empirical evidence of Housing First's improving program outcomes. At around the same time, due to over- reliance on a single metric, an anti-Housing First Coalition emerged that challenged Housing First's insistence on excluding other approaches to addressing homelessness.
The amount of funding that congressional committees approved for additional HUD-VASH vouchers decreased, even as program effectiveness and need increased. This suggested declining congressional willingness to justify further program expansion amidst the contention and ambiguity over the Housing First strategy for addressing homelessness.
The findings suggest that the policy disagreements have not been over whether the HUD-VASH program should remain sufficiently funded or about the actual underutilization of vouchers (the usage rate was more or less consistent between 2019 and 2024) since 2019. Rather, they revolved around whether to proceed programmatically as long as the Housing First policy strategy was linked to housing vouchers for veterans.Master of ArtsAddressing homelessness among military veterans generally is broadly supported, but appropriate and effective means of doing so often generate heated debate. Frequently, such debate reflects poorly defined strategies for addressing a policy problem or insufficient coordination and funding among federal agencies. This study examines why federal funding for additional HUD-Veterans Affairs Supportive Housing (HUD-VASH) housing vouchers declined between 2009 and 2024, even though most outcomes displayed increases in effectiveness above and beyond the general population's voucher program.
The study found that congressional concerns over program efficiency and direction were key. Ambiguity centered around the Housing First policy strategy as one of the two features that distinguished the voucher program for veterans from that for the general population. Over time, HUD-VASH effectiveness at reducing veteran homelessness grew, but funding for expanding it to meet growing demand languished. The advocacy coalitions supporting and opposing Housing First identified this policy strategy as both the pre-eminent "cause" of and the "cure" for underutilization of vouchers, complicating congressional debate. The contentiousness of the rhetoric surrounding Housing First coincided with a decrease in funding for expanding the HUD-VASH program, essentially limiting growth. Peculiarities were also unearthed regarding veteran population reductions.
These findings suggest that the policy disagreements were less over whether the HUD-VASH program should be funded and more over whether to proceed programmatically with the Housing First strategy that was linked to veterans. To reduce policymakers' doubts about continuing or expanding the program, the program's features needed to demonstrate effectiveness and efficiency. Yet the general absence of relevant data (or data that were ignored) confused analyses and weakened legislative and other support
Beyond Oil Wealth: Resiliency of the Aliyev Administration in Azerbaijan
No full textIn political science literature, many scholars highlight how natural resources, particularly oil, have often been more of a curse than a blessing for developing countries. The Dutch Disease phenomenon highlights that the rapid development of the natural resource sector leads to a decline in other sectors, primarily the manufacturing and agricultural industries. It also leads to currency appreciation, which makes a country's exports more expensive and less competitive in the global markets. Politically, developing countries with rich natural resources tend to be more authoritarian, and oil wealth contributes to the durability of authoritarian regimes.
Many scholars have predicted that oil-dependent regimes would be vulnerable to oil price shocks and periods of declining production. However, examining the political trajectories of oil-dependent regimes during this period reveals that while some have experienced political instability and regime breakdown, others continue to remain in power. The literature on the politics of oil offers some insights into why certain regimes persist while others collapse during oil price shocks. However, the terminal decline in oil production is an emerging concept, and its political impact has received limited attention in the literature.
In a case study of Azerbaijan, this dissertation aims to explain the durability of Ilham Aliyev's oil-dependent regime amid a terminal decline in oil production that started in 2010. Drawing on theories of how political institutions contribute to regime durability, this dissertation will highlight the role of the regime's ruling New Azerbaijan Party and its coercive institutions in maintaining power during this challenging time.Doctor of PhilosophyOil is a significant commodity that generates substantial revenues for oil-producing countries. While it is often viewed as "manna falling from heaven", according to some scholars, it has curse-like properties that lead to economic and political underperformance, such as undiversified economies and durable authoritarian regimes.
Oil-dependent regimes are often vulnerable to fluctuations in oil prices. During difficult times, such as when global oil prices decline, they are forced to make significant budget cuts and raise taxes, which could lead to public and elite dissent, political instability, and regime breakdown. Most literature on oil politics focuses on the temporary periods of oil booms and busts, as well as their economic and political implications. However, very few studies focus on the impact of a terminal decline in oil production, a severe, irreversible issue that could threaten the political stability of authoritarian regimes.
In a case study of Azerbaijan, a country heavily dependent on oil revenues that entered a stage of terminal decline in oil production in 2010, this dissertation aims to explore the resilience of Ilham Aliyev's regime during this challenging period. Drawing on theories of political institutions in the literature on authoritarianism, this dissertation will examine the ruling New Azerbaijan Party and the coercive institutions that ensure the country's political stability and regime durability
Frontiers in Psychiatry
No full textMental disturbances and related symptoms in the perinatal period present a challenge to patients and providers alike, particularly regarding identification and appropriate management. Perinatal Mental Health (PMH) screening occurs in clinical settings on a more regular basis thanks to guidelines recommending the use of validated screening measures used at perinatal visits. However, patients report several concerns when completing these screeners and providers report barriers in addressing the results. To address barriers and enhance the PMH screening experience, our team of clinicians and researchers propose a tool – the PMH Connect: a Perinatal Mental Health Screening Connection, Education, and Decision Aid – to be given to the patient at the same time as a PMH screener. The PMH Connect provides brief anticipatory guidance about PMH symptoms, normalizing trauma-informed language about prevalence, and provides a connection to resources in a supportive, unobtrusive manner. PMH Connect helps patients feel heard and supported and provides resources before patients need them, which decreases the burden on patients and providers alike. Inspired by the Cycle to Respectful Care framework, PMH Connect is designed to shift power to patients themselves, as valued experts on their own care team, by offering them connections to information and resources through this simple tool. Our hope is that PMH Connect will bridge many of the barriers to effective PMH screening, assessment, and treatment by improving patients’ experiences and outcomes with the ultimate goal of optimizing screening effectiveness and care connection to improve maternal and infant health.Published versio
Modeling and Mitigation of EMI from Near-Field Coupling Effects in Front-End Power Supplies
No full textSwitch-mode power converters are essential in many emerging and rapidly evolving industries including renewable energy, electrified transporation, telecommunications, and datacenters. Increasing performance demands in these markets have driven significant advancements in the development of high-density, high-efficiency power supplies. Many of these advancements have been enabled by the widespread commercialization of wide-bandgap (WBG) power semiconductors. The improved performance of WBG devices over traditional silicon devices has enabled significant increases in switching frequency and power density without compromising power efficiency.
However, some challenges remain which complicate high-density converter design. Electronic products are required to meet certain electromagnetic compatability (EMC) standards, yet EMC is often not addressed until late in the design cycle through trial-and-error methods. Even when EMC is considered earlier, models can underestimate the levels of electromagnetic interference (EMI) observed in hardware testing. These discrepancies are often caused by parasitic electromagnetic couplings within the hardware, which create additional propagation paths for high-frequency noise that may not be attenuated by the EMI filter. This dissertation proposes a framework to model and mitigate EMI from capacitive and magnetic (near-field) coupling effects within front-end AC/DC power supplies. Equivalent noise models are developed, and the key couplings that most significantly impact conducted EMI are identified. Three-dimensional (3D) finite-element analysis (FEA) simulations are used to predict the values of these couplings based on the converter's layout and mechanical design. By combining analytical and FEA models, the conducted EMI spectra can be accurately predicted before building a hardware prototype.
The most significant near-field coupling effects are caused by inductive (magnetic field) and capacitive (electric-field) interactions between the high-frequency switching power stage and the passive EMI filter. These couplings can increase both the common-mode (CM) and differential-mode (DM) conducted noise. Therefore, separate CM and DM noise models are developed to model both the magnetic and capacitive coupling effects. Existing models are often incomplete or rely on physical hardware measurements to fully characterize the conducted noise. The combination of anaytical and FEA models in this dissertation enables quantitative EMI prediction based on the physical arrangement of electrical components and mechanical structures. This allows EMC to be optimized alongside electrical, thermal, and other system requirements earlier in the design cycle.
There are many techniques which can be used to mitigate parasitic couplings and reduce the conducted noise. In this dissertation, the proposed EMI modeling framework is used to describe the mechanism and effectiveness of various mitigation techniques including shielding, magnetic design, component rotation, and coupling cancellation. Additionally, a novel integrated shield structure is proposed for PCB-winding magnetics. This structure is applied to a PFC inductor to contain its electric field and reduce the converter's CM noise by as much as 28 dB, without causing any significant increase in converter loss.
The modeling and mitigation strategies are first demonstrated using a relatively simple bridgeless PFC converter in order to facilitate an easier understanding of the concepts. Then, these techniques are applied to a two-channel interleaved bridgeless PFC using a coupled inductor structure. The EMI modeling and mitigation framework proposed in this dissertation can ultimately be extended to predict and reduce the conducted noise of any front-end power supply with EMI filter.Doctor of PhilosophyModern electronic systems such as renewable energy equipment, electric vehicles, data centers, and communication networks depend on compact and efficient power converters to operate reliably. As these technologies continue to advance, the demand for smaller and more capable power hardware has increased. New semiconductor materials have helped meet this demand by allowing power converters to switch electrical energy faster and with less power loss. However, there are additional challenges that arise when designing high-frequency, high-density power converters.
One of the most challenging aspects is to limit unwanted electrical noise from the power converter. Electronic products are required to meet certain regulatory standards that limit how much electromagnetic interference (EMI) they can produce. However, the amount of EMI generated by the converter can be difficult to predict and is often not known until the converter is constructed and evaluated in the laboratory. Waiting until the end of the design cycle to address EMI issues can introduce costly redesigns and production delays. This dissertation focuses on modeling the EMI behavior of power converters by accounting for an often-overlooked aspect, where different electronic components interact through the electric and magnetic field. By accounting for these interactions using analytical and simulation tools, the converter's EMI spectrum can be accurately predicted early in the design process. In this way, EMI mitigation techniques can be incorporated proactively to ensure a successful final product
Analysis of a Nonlinear vibration absorber for vibration control in a hand-held impact machine
No full textHand-held impact machines (HIMs), such as jackhammers and chipping hammers, operate through the repetitive impacts of a percussive mechanism. Due to their widespread use, it is essential that these tools are designed for safe daily operation. This need is underscored by the fact that approximately 20% of operators risk developing vibration-related hand injuries, which can be career-ending. As a step toward improving the safety of these tools, this dissertation focuses on modeling their dynamic behavior to evaluate the effectiveness of vibration control strategies. The novelty of this work lies in the use of nonlinear mass– spring–damper models to describe tool dynamics, coupled with lumped-mass models of the hand–arm system. Traditionally, linear models have been employed for such evaluations; by contrast, this study introduces nonlinear modeling to capture the more realistic dynamics of HIMs. Furthermore, the role of a cubic nonlinear absorber in attenuating vibrations transmitted to the hand is systematically investigated through this framework. Key findings include the observation of nonlinear phenomena such as unstable periodic solutions, quasi- periodicity, chaos, and grazing. Frequency response analyses demonstrate the superiority of the cubic absorber over its linear counterpart, with notable improvements in performance when combined with an inerter. Parametric studies further reveal how the absorber can be tuned to enhance vibration attenuation across different nonlinear HIM models.Doctor of PhilosophyHand-held impact machines like jackhammers and chipping hammers are widely used in construction, mining and manufacturing but can expose workers to harmful vibrations. Long- term use can cause hand–arm vibration syndrome (HAVS), a condition affecting nearly 20% of operators and leading to pain, loss of grip, and even permanent disability. This dissertation develops mathematical models to better understand how these vibrations occur and how they can be reduced. Unlike traditional studies that rely on simplified linear models, this work uses nonlinear models that more accurately capture the complex dynamics of impact tools and their interaction with the hand–arm system. A special focus is placed on testing cubic nonlinear absorbers — devices designed to counteract vibrations. Results show that these absorbers can outperform standard designs, especially when combined with an inerter element, and offer pathways for safer tool design. Ultimately, this work aims to guide engineering solutions that reduce injuries and extend worker careers
Application of Co-Design Principles for Design of Series Elastic Joints
No full textCompliant joints enhance the performance of dynamic legged robots by enabling more robust, efficient, and resilient locomotion. A widely adopted approach for introducing compliance into robotic joints is the use of Series Elastic Actuators (SEAs). Designing SEAs, however, requires balancing the stiffness of the elastic element with the structure and gains of the control system, as both strongly influence actuator bandwidth, disturbance rejection, and overall efficiency. Prior work across many domains has demonstrated that co-design methodologies, those that optimize mechanical and control parameters simultaneously, can produce high-performance, robust systems.
This dissertation advances the capabilities of dynamic legged robots through the development of a comprehensive co-design strategy for SEAs. The proposed framework addresses key limitations of traditional SEA design, particularly their difficulty in balancing the trade-off between high bandwidth achievable by stiff actuators and the disturbance rejection afforded by increased compliance. By jointly optimizing the gains of a simple, easily implemented PID–feedforward controller alongside the stiffness of the elastic element, the approach presented here improves both controllable bandwidth and transient response without requiring complex control architectures. A systematic method for identifying cost functions that are broadly applicable, implementation-friendly, and reliably indicative of system performance is presented. These cost functions are then used within a co-design optimization applied to several SEA configurations, demonstrating both generality and performance improvements over conventional sequential design approaches.
In addition, this work investigates how infill density influences the flexural rigidity of fused deposition modeling (FDM) printed PLA beams. These experiments support the use of FDM-printed components as compliant elements within SEAs. Using static three-point bending tests, regression models are developed to predict part flexural rigidity as a function of print infill. These models are integrated into the co-design framework, replacing direct selection of elastic stiffness with the specification of beam geometry and infill percentage. The resulting co-designed hardware is validated on an SEA knee-joint test bench, and experimental results are compared with simulations to evaluate sim-to-real fidelity.
This work makes three key contributions: (1) the development of a broadly applicable co-design methodology for SEAs, (2) the creation of predictive regression models for the mechanical properties of FDM-printed PLA beams, and (3) the integration of these results into a unified co-design strategy enabling SEAs that leverage additively manufactured compliant elements.Doctor of PhilosophyRobotic legs and joints work better when they include some flexibility, which helps robots move more smoothly, handle unexpected bumps or impacts, and use energy more efficiently. One common way to add this flexibility is with a device called a Series Elastic Actuator (SEA), which places a spring between the motor and the load. Designing these systems is challenging because the spring's stiffness and the controller that drives the motor must work together. Changing one affects the performance of the other. Recent research has shown that a "co-design" approach, where both mechanical design and control design are optimized at the same time, can create systems that perform better than traditional methods.
This dissertation introduces a new co-design strategy for improving SEAs used in legged robots. The goal is to reduce a major drawback of SEAs: they usually offer strong resistance to disturbances but have lower speed and responsiveness than rigid actuators. By carefully choosing both the controller settings and the stiffness of the elastic element at the same time, this method increases responsiveness without relying on complicated control schemes. A clear process for selecting the performance measures used in this optimization is also presented, helping ensure that the results apply to many different SEA designs.
The research also explores how 3D-printed materials behave when used as flexible elements in these actuators. Specifically, it studies how the internal density ("infill") of 3D-printed PLA beams affects their stiffness and their ability to absorb vibration. Using bending tests and vibration measurements, mathematical models are created to predict how these beams will behave when printed with different settings. These models are then added to the co-design framework so that the optimization can select not just spring stiffness, but actual 3D-printing parameters such as beam geometry and infill percentage. The final designs are tested on a physical robotic joint to compare their real-world performance with simulation results.
Overall, this work makes three main contributions: it introduces a broadly useful co-design method for SEA-based joints, provides new models for predicting the behavior of 3D-printed flexible parts, and combines both results into a unified design strategy for building next-generation robotic actuators that are flexible, customizable, and accessible