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Undergraduate Research Opportunities Program

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Office of Undergraduate Education

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Now showing 1 - 10 of 253

Multidimensional Allocation: In Apportionment and Bin Packing

(Georgia Institute of Technology, 2022-08) Chiu, Alvin

In this thesis, we deal with two problems on multidimensional allocation, specifically in apportionment and in bin packing. The apportionment problem models the allocation of seats in a House of Representatives such that it is proportional to the dimensions being represented. One example is the allocation of the 435 House seats to the 50 U.S. states, which demands being proportional in the one dimension of state population. It is also common to demand proportionality in both state population and political affiliation, where we now have to allocate to two dimensions simultaneously. We begin by investigating what it means for an 1-D apportionment to be "fair", and use this to judge the various methods of apportionment that have been used throughout history. This motivates the study of divisor methods, a certain class of apportionment methods that avoid any paradoxes. We then formally tackle the problem of 1-dimensional and 2-dimensional apportionment with divisor methods through the lens of optimization. The optimization approach generalizes well to higher dimensions, but a proportional apportionment is not always possible in 3 or more dimensions. Our thesis outlines the current method for finding "approximate" apportionments and improves it in certain regimes. As for bin packing, we model the allocation of virtual machines to servers (with limited capacity) in cloud computing, with the goal of designing and analyzing efficient algorithms that optimize the expected cost of the allocation. This builds off previous work that only considered the case where the items being packed had a one-dimensional size. We extend some of those results to items with multi-dimensional size in this thesis.
Auto-Adapting Circuit Topology for Efficient Wireless Power Transfer via Magnetic Resonances

(Georgia Institute of Technology, 2022-08) Radcliff, Johnathan McKinley

As the world moves away from using wired connections to transmit data, wireless power transfer (WPT) offers another opportunity for "cutting the cord." Technologies such as magnetic induction and radiative transmission already allow for energy to flow without a physical medium. However, these solutions are not without their limitations: magnetic induction's short range keeps devices tethered to their charging docks, inhibiting mobility; radiative transfer is highly inefficient and has safety concerns due to high-energy radiofrequency exposure. Recently, WPT via magnetic resonance coupling has been proposed to replace these technologies in short-to-midrange applications due to its high efficiency and high-power throughput. Multitudes of research studies have proven its viability but fail to regard its implementation in real-world usage. In this paper, a wireless energy system is proposed that can automatically alter its circuit parameters as coil distance or alignment changes to maximize energy efficiency. Experimentation verifies this functionality and discovers a maximum end-to-end efficiency of 80.8% and an average operating efficiency of 68.7% over all distances between 0 and 1000 cm.
The effects of 40 Hz gamma flicker stimulation on spatial memory, perceptual discrimination, and recall

(Georgia Institute of Technology, 2022-08) Salen, Ashley

The rising prevalence of Alzheimer's Disease (AD), which leads to progressively deteriorating memory and thinking skills is alarming. A preliminary data analysis was performed to predict potential behavioral changes that may occur in cognitively healthy older adults between conditions as a result of using the flicker for 8 weeks. Although the preliminary data analysis has not yet yielded any statistically significant effects induced by the 40 Hz gamma flicker on the memory of the flicker group compared to the control group, it may provide insight into what the results could look like further down the line. Based on graph analysis, it could be predicted that the flicker group may have fewer spatial memory deficits.
Cyclic mechanical stretch upregulates Akt, MAPK, and NF-kappaB signaling pathways in BV2 microglia

(Georgia Institute of Technology, 2022-05-24) Udeshi, Kareena Jaydeep

Mild traumatic brain injury (mTBI) is prevalent in contact sports. Post injury, microglia in the central nervous system are known to produce an inflammatory response. Moreover, with repeated injuries, chronic inflammation may be sustained, which is detrimental to the host. This study focuses on the signaling pathways that are activated with brain injury-induced injury. We hypothesize that mechanical stretch activates inflammatory signaling pathways in microglia. This experiment utilized impulse, cyclic, and sham-stretch conditions in the presence or absence of the mechanosensitive channel inhibitor GSMTx4. Afterwards, the cell lysate was collected, and the samples were analyzed by a Luminex multiplexed ELISA to determine if there was a change in protein phosphorylation across 27 phosphoproteins in three main signaling pathways: Akt, MAPK, and NFkB. My data showed that GSMTx4 had little impact on phosphorylation, but it did increase the expression of the Akt pathway proteins. Nonetheless, the minimal role GSMTx4 played in the measured phospho-protein signaling pathways at acute timepoints could imply that Piezo1 does not play a direct role in acute pathway activation. Of note, however, a control 20% cyclic stretch resulted in an upregulation in phosphorylation in all signaling pathways. As such, future studies will include GSMTx4-treated BV2 microglia that undergo cyclic stretch at varying degrees. Clinically, this data is useful in understanding how sustained injury can force the progression of neurodegenerative diseases.
Six Feet Apart: Online Payments During the COVID-19 Pandemic

(Georgia Institute of Technology, 2022-05) Shaikh, Omar

Since the COVID-19 pandemic, businesses have faced unprecedented challenges when trying to remain open. Because COVID-19 spreads through aerosolized droplets, businesses were forced to distance their services; in some cases, distancing may have involved moving business services online. In this work, we explore digitization strategies used by small businesses that remained open during the pandemic, and survey/interview small businesses owners to understand preliminary challenges associated with moving online. Furthermore, we analyze payments from 400K businesses across Japan, Australia, United States, Great Britain, and Canada. Following initial government interventions, we observe (at minimum for each country) a 47% increase in digitizing businesses compared to pre-pandemic levels, with about 80% of surveyed businesses digitizing in under a week. From both our quantitative models and our surveys/interviews, we find that businesses rapidly digitized at the start of the pandemic in preparation of future uncertainty. We also conduct a case-study of initial digitization in the United States, examining finer relationships between specific government interventions, business sectors, political orientation, and resulting digitization shifts. Finally, we discuss the implications of rapid & widespread digitization for small businesses in the context of usability challenges and interpersonal interactions, while highlighting potential shifts in pre-existing social norms.
Measuring Cerebral Blood Flow in a Mouse Model of Alzheimer's Disease

(Georgia Institute of Technology, 2022-05) Daniel, Christy

Mild traumatic brain injuries (mTBIs), which are defined by an absence of overt structural damage in the brain have been associated with an increased risk of Alzheimer's Disease when sustained multiple times over an interval. Within mTBI, indirect evidence suggests that persistent post-concussive symptoms may be linked to reduced cerebral blood flow (CBF), of which deficits have been observed in cases of Alzheimer's Disease. Diffuse correlation spectroscopy (DCS) is a non-invasive optical method that uses near-infrared light to measure fluctuations in intensity that are caused by moving red blood cells that can be used to measure cerebral blood flow (CBF) in C57bl/6 mice. This dissertation will adapt this novel protocol to a mouse model of Alzheimer’s Disease (3xTg). This strain will be utilized due to its accelerated AD pathology and the presence of literature that have observed impairments in CVR, CBF, among other biomarkers of Alzheimer’s Disease and traumatic brain injury. Given the smaller size of the 3xTg mice compared to C57bl/6, the DCS optical sensor must be modified. Herein, the design of a smaller sensor is detailed, along with a series of validation tests, which include measurements on a liquid phantom with known flow properties and on a pilot cohort of four 6–7-month-old 3xTg mice (2 males, 2 females). This data provides the foundational work to characterize the feasibility of DCS as a technique to monitor CBF and CVR in 3xTg mice for future experiments.
The Effects of Nerve Injury and Synaptic Preservation on Motoneuron Activity

(Georgia Institute of Technology, 2022-05) Garcia, Violet

Peripheral nerve injury currently has a poor prognosis that often results in motor deficits such as discoordination and co-contraction of muscle antagonists (Brushart, 2011; Horstman et al., 2019). Because of this, studying the effects of peripheral nerve injury on the morphology and functional connectivity of the central nervous system (CNS) is of utmost importance. Our study centers around the anatomical changes that occur after peripheral nerve injury in the rat spinal cord, namely the degradation of Ia input defined by the expression of the vesicular glutamate transporter 1 (VGLUT1). This study is based on the proposed microglia-dependent mechanism of permanent synaptic loss from the Rotterman et al. (2019) paper. We ask if 1) we can suppress microglia accumulation with minocycline, a tetracycline antibiotic, and 2) if using minocycline can help preserve the Ia sensory afferent synapses after nerve injury. We first retrogradely labeled the medial gastrocnemius motor pool in 15 adult Wistar rats. One week later, we transected the medial gastrocnemius nerve in the left hindlimb. Rats were either treated with vehicle or minocycline for 14 days following injury. Control animals were also produced. At 14 days post injury, animals were perfused, spinal cords were collected and subsequently sectioned. Using immunohistochemistry (IHC), we labeled VGLUT1 synapses on these injured motor neurons and imaged them with confocal microscopy for subsequent reconstruction and analysis. We found four main results: 1) treatment with minocycline for 14 days after nerve injury does not seem to prevent microglia proliferation, 2) the chromalytic reaction (somatic expansion) that commonly occurs after axotomy did not seem to occur in the minocycline- treated animals, 3) there was partial preservation of somatic VGLUT1 synapses in the minocycline-treatment animals, and 4) there was complete dendritic VGLUT1 synapse preservation in the minocycline-treated animals. Although there were limitations to the study with regards to the methods of counting microglia, the study produced robust conclusions that will aid in the development of further research. Future studies should be conducted on the efficacy of minocycline preserving the synapses, the molecular mechanisms underlying minocycline’s effects, and the potential recovery of nerve function.
Improving Online Instructional Design using Memory, Attention, and Engagement

(Georgia Institute of Technology, 2022-05) Chanda, Ritika

Neuroscience research supports a relationship between the psychological constructions of attention and engagement. The level of selective attention and engagement present during the learning process correlates with increased memory and recall. With the recent rise in online learning, new questions regarding the improvement of educational design, teaching techniques, and learning have created a new avenue of investigation within the field of Neuroeducation. The objective of this study is to identify whether attentional brain networks related to Gagné’s Nine Events of Instruction and engagement can predict learning in an online setting by using fMRI and behavioral techniques. Overall, we found fMRI evidence of engagement, verified engagement’s role in memory and retrieval, and identified three Gagné events (Events 5, 6 and 7) that increase learning among students. This investigation allows for further advancements in online educational design as it will provide instructors with guidance on how to properly build their curriculum and modify the content structure of online classes to highlight techniques that promote successful learning.
Examinator: Detecting Exam Cheating Via Comparison of Question Answering Timings

(Georgia Institute of Technology, 2022-05) Sonubi, Imanuel Oluseyi

Cheating is an issue that affects more than just the student doing it, no matter the format of the assessment being cheated on. Take-home exams provide more flexibility for the instructor and student than regular proctored exams, but it is that lack of proctoring during the exam that makes cheating trickier to detect -- students may meet up outside of the classroom and inappropriately collaborate on these tests even though they are to be done individually. Examinator aims to detect cheating on Canvas take-home exams by examining the times at which students view questions and comparing them with other students' times to find any exam attempts that have suspiciously similar timestamps for each question.
Learning Rotation-in-Place and Orbiting Policies for a Quadruped Robot

(Georgia Institute of Technology, 2022-05) Kim, Alex

Reinforcement learning (RL) algorithms have successfully learned control policies for quadruped locomotion such as walking, rotation, and basic navigation. We utilize Proximal Policy Optimization and iGibson to train a quadruped robot in simulation to do two specific tasks—rotation-in-place and orbiting—with orbiting being a novel, previously unexplored task for quadruped robots. We show that with proper reward and environment engineering, we are able to train a simple two layer fully-connected neural network to do both tasks. We propose that both policies will be useful in a larger control system for a quadruped robot to explore its environment and that the orbiting policy is both novel and useful for learning more about certain objects of interest in the environment. See policy video here: https://youtu.be/olk2hJ372a4.