Digital Commons Network^™

Exploring Longitudinal Stability Of Spatiotemporal Sequential Patterns By Means Of Autoencoder Schemes For Eeg Based Personal Identification, Muhammed E. Oztemel

LSU Doctoral Dissertations

Robust personal identification remains a critical and challenging task in the digital era. Electroencephalography (EEG) offers a unique biometric modality that captures individual brain dynamics through complex neural signals. This dissertation proposes autoencoder (AE) based feature extraction and subject identification through these features. EEG recordings are first transformed into topographic maps to represent spatial brain activity. Consecutive topomaps are then concatenated to capture temporal transitions across frames. Convolutional autoencoders (CAEs) are used to learn spatial and temporal patterns, while domain-adaptive AEs are designed to model evoked potential based responses. Additionally, self-attention mechanism is incorporated to enhance feature representation. To analyze …

Timing And Spectral Evolution Of The Magnetar 1e 1841-045 In Outburst, George Younes, Samuel K. Lander, Matthew G. Baring, Marlon L. Bause, Rachael Stewart, Zaven Arzoumanian, Hoa Dinh Thi, Teruaki Enoto, Keith C. Gendreau, Tolga Güver, Alice K. Harding, Wynn C.G. Ho, Chin Ping Hu, Alex Van Kooten, Chryssa Kouveliotou, Niccolò Di Lalla, Alexander Mcewen, Michela Negro, Mason Ng, David M. Palmer, Laura G. Spitler, Zorawar Wadiasingh

Faculty Publications

We present timing and spectral analyses of Neutron star Interior Composition Explorer (NICER), Nuclear Spectroscopic Telescope Array (NuSTAR), and IXPE observations of the magnetar 1E 1841−045 covering 82 days following its 2024 August bursting activity as well as radio observations utilizing MeerKAT and Effelsberg. We supplement our study with a historical NuSTAR observation and all 2024 preoutburst NICER observations. The outburst is marked by an X-ray flux enhancement of a factor of 1.6 compared to the historical level, predominantly driven by a newly formed nonthermal emitting component with a photon index Γ = 1.5. This flux showed a 20% decay …

Deltaic Engineering-Induced Accumulation Hides Erosion In Response To Fluvial Sediment Decline In The Yangtze Submarine Shoal, Haifei Yang, Lu Wang, Kehui Xu, Wenxiang Zhang, Benwei Shi, Shilun Yang, Ya Ping Wang

Faculty Publications

Worldwide river deltas are impacted by human activities and climatic change, but it has been challenging to quantify their contributions due to nonlinear natural processes and a lack of long-term geomorphological data. Time-series bathymetric data were collected at submarine Hengsha Shoal in the Yangtze Delta during 11 repeat surveys over 60 yr. Our results show that the minimum riverine sediment supply to maintain the shoal's morphology was 229–258 Mt yr⁻¹. Without human impacts, it would have been experiencing net erosion since the operation of the Three Gorges Dam in 2003. However, this shoal has been growing in certain …

Subtropical Marine Cloud Brightening Suppresses The El Niño–Southern Oscillation, C. Xing, S. Stevenson, J. Fasullo, C. Harrison, C. Chen, J. Wan, J. Coupe, C. Pfleger

Faculty Publications

Stratospheric aerosol injection (SAI) and marine cloud brightening (MCB) are two proposed methods of compensating for greenhouse gas-induced warming by reflecting incoming solar radiation. However, their effects on the El Niño–Southern Oscillation (ENSO), a critical mode of climate variability, are poorly understood. Here we use ensembles of climate model simulations to show that deploying MCB in the subtropical eastern Pacific dramatically reduces ENSO amplitude by approximately 61%, while SAI has a negligible impact. MCB increases cloud albedo, which cools the subtropical eastern Pacific and triggers a loss of moist static energy. This cooling promotes atmospheric subsidence, dries the tropical Pacific, …

Rate Of Sea-Level Rise And Sediment Characteristics Modulate Deltaic River-Tide Interactions, Peter Bacopoulos, Celalettin E. Ozdemir, Matthew Hiatt

Faculty Publications

Due to sea-level rise, small river-dominated deltas (< 100 km²) are expected to become more exposed to tidal influences in the future. However, there remains a knowledge gap in the impending hydrodynamics of such deltas, particularly with the interactions between river and tidal flows. In addition to sea-level rise, river-tide interactions in these deltas depend on their morphology, which is influenced by the sand proportion in the particulate matter delivered by rivers. This study investigates river-tide interactions predicted for small deltas formed by different sand-to-mud ratios under various sea-level rise scenarios. Delta morphologies were generated using reduced-order complexity model (DeltaRCM), …

Novel Sequential Modeling Framework Improves Phytoplankton Biomass Predictions In Response To Multiple Environmental Stressors, Zhuyin Tong, Jiayu Guo, Yikai Liu, Lizhen Lin, Jixin Chen, Xin Liu, Bangqin Huang, Edward A. Laws, Wupeng Xiao

Faculty Publications

Understanding the impacts of multiple environmental stressors on phytoplankton biomass is crucial for predicting marine ecosystem responses under global climate change. This study employed a sequential modeling framework integrating principal component analysis, generalized additive models, and artificial neural networks to improve predictions of phytoplankton chlorophyll a concentrations in the Taiwan Strait. Analyzing a decadal dataset, we found that a 2°C rise in sea surface temperature and a 0.2 pH decline will each lead to an 11.3% reduction in chlorophyll a biomass, whereas nitrogen enrichment is expected to increase it by only 2.8%. The combined effects of these stressors will result …

Detected Abundances Of Nuclei Relative To 26fe For Elements 14si Through 44ru With Calet On The International Space Station, O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, P. Betti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, G. A. De Nolfo, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo

Faculty Publications

The Calorimetric Electron Telescope (CALET), launched to the International Space Station (ISS) in 2015 August and continuously operating since, measures cosmic-ray (CR) electrons, nuclei, and gamma rays. CALET, with its 27 radiation length deep Total Absorption Calorimeter, measures particle energy and allows for the measurement of spectra, secondary to primary ratios of the more abundant CR nuclei through 28Ni, while the main charge detector can measure ultra-heavy CR nuclei through 44Ru. The results for the abundances of elements from Z = 14 to Z = 44 relative to 26Fe over 7.5 yr of observation are presented here and compared to …

Measuring The Impact On Landscape And Sediment Transport Of Climate And Anthropogenic Influence In The Mississippi River Since 2000 Bce, Bailey Wycoff

LSU Master's Theses

Understanding river dynamics is crucial to being able to interpret the geological history preserved in sediment deposited on continental margins, deltas, and alluvial plains. Sediment buffering can be a key control on the sediment flux to the ocean and involves sediment storage and recycling in flood plains. The efficiency of the transport varies depending on climatic and more recently anthropogenic influences. Sediment moving through meandering streams may be temporarily deposited in a point bar on the convex side of a meandering river. Meanders are sometimes cut off, creating an oxbow lake and filled in. The area of study, False River, …

Ai-Based Object Detection And Risk Identification For Enhanced Construction Site Safety, Mahdi Bonyaniakbarabadi

LSU Master's Theses

Recent advancements in computer vision for construction site safety have encountered significant hurdles, especially in the nuanced tasks of object detection and the identification of unsafe worker behaviors. These challenges are often exacerbated by complex and cluttered backgrounds, wide variations in object scale, and inconsistent image quality. While existing methodologies have utilized attention mechanisms to analyze spatial and temporal features, they frequently neglect the benefits of adaptive sampling and channel-wise feature adjustments, thereby failing to exploit potential spatiotemporal redundancies. This thesis introduces a two-pronged approach to address these limitations. First, we propose the Optimized-Position Network (OP-Net), a novel architecture for …

A Multi-Scale Numerical Analysis Of Wave Propagation Through Coastal Vegetation Using Proteus & Xbeach, Cole M. Statler

LSU Master's Theses

Coastal vegetation attenuates waves in the nearshore zone and protects shorelines from storm surge and wave action. It also traps nutrients and sediment, and participates in the formation of land over longer time scales. These features of vegetation make it a common component of nature-based engineering projects. Interaction of water waves and flow with vegetation, however, can involve unsteady and turbulent flow, non-hyrdostatic pressure effects, and air entrainment that can hinder the use of simple parametric representations of vegetation drag. XBeach, a one- and two-dimensional production model applies reduced-order methods, prioritizing computational efficiency. Vegetation is represented in XBeach as a …

Characterization Of The Role Of Rsd-6, A Tudor Domain Protein, In Antiviral Rnai Pathway In Caenorhabditis Elegans, Krishna Prasad Dahal

LSU Doctoral Dissertations

RNA interference (RNAi) triggered by virus produced dsRNA intermediate offers robust innate immunity against invading viruses in plants, insects and animals. Caenorhabditis elegans has been extensively used as a model organism to study host virus interaction. Recently, a forward genetic screen identified RNAi spreading deficient-6 (RSD-6), a Tudor domain protein, as a key component in antiviral RNAi pathway against Orsay virus in C. elegans but its contribution in the pathway remained unclear. Here, we generated a rsd-6 null allele using CRISPR-Cas9 genome editing, crossed it with other known RNAi mutants and analyzed Orsay virus replication in them and in combination …

The Operational Performance Of Buildings In A Humid Subtropical Climate: Insights From Empirical Data And Assessment Models, Oluwafemi Awolesi

LSU Master's Theses

This thesis evaluates the operational performance of residential and non-residential buildings in a humid subtropical climate, emphasizing Indoor Environmental Quality (IEQ) and energy performance through empirical data and assessment models. Motivated by the increasing need for integrated sustainability evaluations, this study combines a systematic review with multi-method field investigations to advance understanding in this domain. The systematic review critically analyzed 99 case study articles, identifying dominant IEQ assessment methodologies and highlighting methodological inconsistencies that hinder cross-study comparability. Emerging computational approaches, although promising, remain underutilized. The review advocates for standardized, climate-responsive, and feedback-oriented evaluation frameworks. Field investigations assessed IEQ and energy …

Adaptive Multi-Agent Reinforcement Learning For Electric Vehicle Charging Optimization Under Dynamic Traffic Conditions, Shaghayegh Rabbanian

LSU Master's Theses

Electric vehicle (EV) charging optimization is a critical challenge in sustainable transportation. This study focuses on three fundamental questions: (1) when is the best time to charge an EV, (2) where is the optimal charging location, and (3) how should charging be planned considering navigation and routing decisions. Our primary objective is to determine the optimal time and location for EV charging while accounting for key factors such as real-time traffic conditions, spatial distribution of charging stations, and EV-specific attributes such as state of charge (SOC), driving range, and efficiency. To develop a robust and adaptive EV charging recommendation system, …

Patterns And Processes Behind Secretive Marshbird Movement, Abundance, And Distribution Across Southeastern Louisiana, Leah Moran

LSU Doctoral Dissertations

Restoration and conservation of coastal Louisiana hinges on understanding the patterns and processes underlying habitat heterogeneity on the landscape and therefore the species that inhabits this region, including secretive marshbirds. Elusive in nature, this guild of birds has evolved under dynamic hydroperiods, and myriad plant communities present within wetlands. Only recently, however, has research focused on the role of hydrologic dynamics and vegetative structure and distribution on abundance, movement and detection of marshbirds, specifically within southeastern Louisiana. This study aimed to quantify the ecological patterns and processes, particularly hydrologic processes and landscape structure, driving breeding secretive marshbird movement, abundance and …

Efficient Small Tool Detection In Construction Via Lightweight Deep Neural Networks, Maryam Soleymani

LSU Master's Theses

Construction sites are dynamic and inherently hazardous environments, where small hand tools—although essential—pose serious safety risks due to their frequent use, portability, and tendency to be misplaced or dropped. This study introduces a novel and lightweight deep learning-based architecture, Lightweight Small Tool Detection (LSTD), specifically designed for fast detection of small tools in unstructured and challenging construction environments. Recognizing that small object detection remains a persistent limitation in existing computer vision models, particularly under poor lighting or cluttered backgrounds, LSTD integrates advanced modules for enhanced feature extraction, fusion, and classification. It achieves notable improvements in accuracy, recall, and computational efficiency …

Investigating The Relationships Among Suspended Sediment Concentration, And Marsh Edge Erosion In Barataria Bay, La, Lily Vowels

LSU Master's Theses

Barataria Bay, Louisiana, USA exhibits a unique microtidal, wind-driven hydrodynamic climate where extensive levee infrastructure throughout Louisiana has starved Barataria Bay and similar interdistributary bays of the historic levels of terrigenous sediment import. This has contributed to extreme coastal wetland loss in Louisiana. This project seeks to understand how hydrodynamic and meteorological conditions are linked to sediments’ fate after erosion from the marsh edge. Specifically, this project seeks to differentiate the roles of wave resuspension and marsh edge erosion (MEE) in sediment dynamics in Barataria Bay. An acoustic wave and current profiler (AWAC) was used to capture hydrodynamic conditions, and …

From Devices To The Cloud: Digital Forensics In The Changing Social Media Landscape, Joseph Brown

LSU Master's Theses

This thesis presents a comprehensive digital forensic analysis of emerging and alternative social media platforms, including Truth Social, Threads, Bluesky, Nextdoor, and Neighbors. These platforms, which range from politically aligned alt-tech networks to hyperlocal neighborhood apps, present unique forensic challenges and security vulnerabilities. Across all case studies, established forensic techniques were applied using a hybrid methodology combining mobile device analysis, network traffic monitoring, and API interrogation. Findings include the discovery of plaintext credentials, session tokens, and other sensitive artifacts, particularly in platforms with weaker security postures such as Truth Social, Bluesky, Nextdoor, and Neighbors. Threads, by contrast, demonstrated greater resilience …

Shock Induced Droplet Aerobreakup For Newtonian And Non-Newtonian Fluids, James Leung

LSU Doctoral Dissertations

This research investigates shock-induced aerodynamic breakup (aerobreakup) of fluids with different stress-strain behaviors. The central hypothesis is that shear stress from highspeed gas flow manifests differently depending on a fluid’s strain response, influencing droplet breakup morphology, fragment size distribution, and drag-induced acceleration. To test this, experiments and simulations were performed on μm–mm sized droplets of Newtonian (water) and shear-thinning fluids (nanofluids or xanthan gum). Two experimental setups were used: an open-ended shock tube and a closed conventional shock tube. In the openended setup, a normal shock impacts a stationary droplet held by an acoustic levitator. Droplet breakup and gas dynamics …

Rethinking Green Building Development Through Policy And Operational Metrics: Insights From Baton Rouge And Beyond, Oluwafemi Awolesi

LSU Doctoral Dissertations

This dissertation explores the challenges and opportunities associated with the development, adoption, and performance of green buildings in regions with relatively low certification uptake, drawing insights from Baton Rouge and its parish system as a case study. It addresses three primary research questions: (1) How can the adoption rate of green buildings be enhanced? (2) How do certified buildings perform compared to their non-certified counterparts? (3) What operational metrics can be applied to better evaluate building performance in the future?

Using a mixed-methods approach, the study examines stakeholder perceptions in East Baton Rouge, Louisiana, investigates energy performance, indoor environmental quality, …

Empirical Analysis Of Incentivized Energy Assessment Recommendations And Iiot Cost-Effectiveness In U.S. Smes, Fatemeh Ghafari

LSU Master's Theses

The industrial sector in the United States accounted for 33% of total energy consumption in 2022. Small and medium-sized enterprises (SMEs), which comprise 99.9% of U.S. businesses present a critical opportunity for energy efficiency improvements. Although energy audits provide actionable Assessment Recommendations (ARs) to reduce consumption, high implementation costs remain a key barrier to adoption.

While prior studies have explored rebate programs, most are limited to residential and commercial sectors or focus narrowly on specific technologies or geographic areas for the industrial sector. The objective of this study is to empirically investigate the “Incentivized Assessment Recommendation” (IAR) trends and to …

Super-Resolution Stimulated X-Ray Raman Spectroscopy, Kai Li, Christian Ott, Marcus Agåker, Phay J. Ho, Gilles Doumy, Alexander Magunia, Marc Rebholz, Marc Simon, Tommaso Mazza, Alberto De Fanis, Thomas M. Baumann, Jacobo Montano, Nils Rennhack, Sergey Usenko, Yevheniy Ovcharenko, Kalyani Chordiya, Lan Cheng, Jan Erik Rubensson, Michael Meyer, Thomas Pfeifer, Mette B. Gaarde, Linda Young

Faculty Publications

Propagation of intense X-ray pulses through dense media has led to the observation of phenomena such as atomic X-ray lasing^1,2, self-induced transparency³ and stimulated X-ray Raman scattering (SXRS)⁴. SXRS has been long predicted as a means to launch and probe valence-electron wavepackets and as a building block for nonlinear X-ray spectroscopies^5,6. However, experimental observations of SXRS to date^4,7,8 have not provided spectroscopic information, and theoretical modelling has largely implemented hard-to-realize phase-coherent attosecond pulses. Here we demonstrate SXRS with spectroscopic precision, that is, detection of valence-excited states in neon with a near Fourier-limited …

Quasistatic Peridynamics, Existence Of Unique Solution In The Presence Of Damage, Nuwanthi N. Samarawickrama

LSU Doctoral Dissertations

A mathematical model for damage propagation based on nonlocal potentials is developed within the framework of peridynamics. This model is applied to simulate damage evolution in cyclically loaded structures. By neglecting inertial effects, a well-posed quasistatic formulation for cyclic loading is obtained.\\ The resulting equation is expressed as a nonlocal and nonlinear integral operator that couples damage evolution to the deformation field.\\ This coupling occurs through the product of a damage factor and the derivative of a force potential. The damage factor ranges between zero and one, where one represents undamaged material and zero indicates complete damage.\\ It serves to …

Retrospective Study And Predictive Modeling Of The Impact Of Social Determinants Of Health On Sepsis Outcomes, Mwembezi Aaron Nyelele

LSU Doctoral Dissertations

Sepsis, a life-threatening organ failure caused by the body’s abnormal and harmful response to an infection, remains a major global and national health challenge. In the United States, it contributes significantly to hospital mortality and imposes a substantial economic burden, with billions spent annually on treatment. Early diagnosis is difficult due to the nonspecific nature of sepsis symptoms, often leading to delays in care and poorer outcomes. As the incidence and severity of sepsis rise, identifying factors that influence outcomes is increasingly critical. Emerging research has shown that Social Determinants of Health (SDOH), including economic stability, education, neighborhood and built …

Towards Leveraging Social Media Data For Fostering Collaborations Among Non-Profits, Monazil Chowdhury

LSU Doctoral Dissertations

Nonprofit organizations serve a crucial role in tackling a wide range of significant social, environmental, and economic issues. But it is often hard to get a clear picture of their work because their information is spread out and it is difficult to see how they are collaborating. To address this issue we developed a web-based tool to collect scattered data—from a variety of sources, such as the IRS, social media, and the Census, into one easy-to-use resource. The tool begins by taking IRS records and geocoding each nonprofit’s physical address With its coordinates. It then retrieves census tract information from …

Digital Forensics And Ai: Artifact Analysis And Using Ai In The Forensics Domain, Clinton Joel Walker

LSU Doctoral Dissertations

Digital Forensics (DF) is a field of forensic science focusing on the acquisition, authentication, and analysis of digital evidence while maintaining integrity of that data. DF analysts use forensic tools to parse large volumes of data for investigations and depend on them for identification of pertinent digital evidence in vast amounts of data. Keeping up with innovations and ever-expanding data volumes is a constant challenge for these investigators. The prevalence of Artificial Intelligence (AI) in everyday computing is rapidly expanding, with the use of Machine Learning (ML) and Large Language Models (LLM)s becoming increasingly commonplace. Innovations in technology bring new …

The Design And Effect Of Continuum Robot Compliance On Locomotion, Parsa Molaei

LSU Doctoral Dissertations

Continuum robots, due to their compliant structures and ability to navigate through constrained environments, offer significant advantages in applications requiring safe physical interaction and dexterous motion. However, challenges related to limited structural stiffness, payload capacity, and precise control remain open problems in the field. This dissertation presents novel contributions aimed at addressing these limitations through two main actuation units of continuum robots: tendon-driven continuum robots (TDCRs) and concentric tube robots (CTRs). In the first part, we focus on methods to improve the stability and modify the stiffness of the TDCR. A tendon decoupling strategy is introduced for planar TDCRs. The …

A Systems Engineering Approach To Improve Alarm Management And Nurse Mental Workload, Benjamin D. Elmore

LSU Doctoral Dissertations

Alarm fatigue has been a consistent problem nurses have experienced for decades. The effects of excessive nuisance alarms leads to adverse effects such as desensitization, missed alarms, frustration, and increased risk to patient safety. Other research has provided explanations on alarm fatigue causes and developed solutions for reducing nuisance alarms or minimizing effects, but few have examined the problem from a sociotechnical systems perspective. This study applied the Systems Engineering Initiative for Patient Safety (SEIPS) framework to define, design, and test an alarm management intervention compatible with a Progressive Care Unit (PCU)’s sociotechnical subsystems. The SEIPS application is unique from …

Anion Exchange Membrane Transport And Accelerated Testing Methods For Co2 Electrolyzers With Cu-Based Electrocatalyst, John C. Hendershot

LSU Doctoral Dissertations

Electrocatalytic carbon dioxide (CO₂) reduction to C₂₊ products holds promise for low carbon intensity fuels, chemicals, and food; however, durability challenges, particularly bicarbonate (HCO₃^-)and carbonate (CO₃^2-) salt precipitation, hinder their commercialization. This report considers water (H₂O) and ion transport properties of conventional anion exchange membranes (AEMs) in zero-gap membrane electrode assembly (MEA) configurations using Cu electrocatalysts. Transport characterization includes H₂O diffusion, permeability, potassium (K⁺) diffusion, and transference numbers using three commercial AEMs, including piperidinium-based (Versogen), quaternary ammonium-based (Fumasep), and imidazolium-based (Dioxide Materials) membranes. Accelerated lifetime …

Soft Hexapod Robot With Tendon-Driven Continuum Legs For Internal Infrastructure Inspection, Setayesh Yavari

LSU Master's Theses

The need for robotic systems capable of operating in confined, hazardous, or complex environments has driven interest in soft and legged platforms for industrial inspection and structural integrity assessment. This thesis presents the design and fabrication of a tentacle-like, soft-legged hexapod robot, which uses six cable-stiffened, pre-curved, tendon-driven continuum robot (TDCR) legs. These biologically inspired legs are designed to offer a balance between compliance and control, enabling the robot to navigate unstructured terrains and potentially grasp cylindrical structures such as pipes. The design phase involved the development and comparison of multiple leg geometries using CAD modeling and finite element analysis …

Gain Threshold Optimization Using Fano Resonance, Alina Oktiabrskaia

LSU Doctoral Dissertations

The study of resonances in electromagnetics plays a critical role in the design of optical systems. This dissertation investigates the interaction between resonance and gain in optical structures to establish a universal principle for achieving ultra-low-threshold lasing. Through the analysis of geometric symmetries, material properties, and coupling mechanisms, this research develops prototype structures applicable to a wide range of optical and electromagnetic systems. A range of models is considered, starting from a simple onedimensional string-resonator system (based on the model of H. Lamb), then advancing to two- and three-dimensional waveguide models, and culminating with a realistic high-contrast model in open …