Digital Commons Network^™

Neural Networks For Interference Mitigation In Satellite Communication Systems, Martha E. Cash

LSU Master's Theses

The objective of this thesis is to utilize the power of machine learning to develop a neural network-aided receiver in a DVBS-2X satellite communication system to improve the downlink transmission quality in the presence of interference. An emphasis is placed on mitigating the effects caused by non-linear distortions, carrier frequency offset, and additive white Gaussian noise. This thesis proposes a feed-forward neural network with two hidden layers to compensate for the distortions in the received signal. The proposed system model uses 16-APSK modulation scheme. The neural network is tested under varying degrees of non-linear distortion, frequency offsets, and varying levels …

Characterization Of Electrophoretic Deposited Zinc Oxide Nanopartices For The Fabrication Of Next-Generation Nanoscale Electronic Applications, Fawwaz Abduh A. Hazzazi

LSU Doctoral Dissertations

Several reports state that it is crucial to analyze nanoscale semiconductor materials and devices with potential benefits to meet the need for next-generation nanoelectronics, bio, and nanosensors. The progress in the electronics field is as significant now, with modern technology constantly evolving and a greater focus on more efficient robust optoelectronic applications. This dissertation focuses on the study and examination of the practicality of Electrophoretic Deposition (EPD) of zinc oxide (ZnO) nanoparticles (NPs) for use in semiconductor applications.

The feasibility of several synthesized electrolytes, with and without surfactants and APTES surface functionalization, is discussed. The primary objective of this study …

Surpassing The Standard Quantum Limit Using An Optical Spring, Torrey Cullen

LSU Doctoral Dissertations

In 1916, Albert Einstein predicted the existence of gravitational waves based on his new theory of general relativity. He predicted an accelerating mass with a non-zero quadrupole moment would emit energy in the form of gravitational waves. Often referred to as ripples in space-time, gravitational waves are extremely small by the time reach Earth, potentially having traveled hundreds of megaparsecs. It is common for these ripples in space-time to stretch and squeeze matter 1000 times smaller than the width of a proton.
Laser interferometer observatories were first built in the 1990s in the US and Europe, and as sensitivity improvements …

Spatial Variations In The Stress Field Near The Wilmington Blind-Thrust, An Earthquake Source Beneath Los Angeles, California, Justin Kain

LSU Master's Theses

A newly identified blind-thrust fault in the southern Los Angeles basin may have substantial implications for earthquakes in the region. A previous study suggests that the Wilmington blind-thrust may link up with nearby faults to produce a multisegment (M_w 6.6–7.4) earthquake rupture. These estimates are based on the joint rupturing of the Wilmington blind-thrust, Compton, Newport Inglewood, and the Huntington Beach fault segments (~85 km total length). However, stress heterogeneity near these faults may limit the size and intensity of earthquakes when incorporated into earthquake hazard modeling. This study presents a detailed model of the stress field in this …

Breeding Ecology Of Mottled Ducks In Southwestern Louisiana, Elizabeth Sophia Bonczek

LSU Doctoral Dissertations

Mottled ducks are a resident species found in the southern United States that rely on coastal marsh and associated habitat to fulfill the needs of the entirety of their annual cycle. Population monitoring has revealed declines in western Gulf Coast (WGC) mottled ducks since 2008. Mottled duck populations are influenced by survival and recruitment, and changes in these factors may contribute to population declines. The overarching goal of this project was to identify the mechanisms potentially limiting WGC mottled ducks.

I captured adult female mottled ducks during molt on Rockefeller Wildlife Refuge and adjacent lands in southwestern Louisiana from 2017–2019. …

A Wet/Dry Point Treatment Method Of Fvcom, Part Ii: Application To The Okatee/Colleton River In South Carolina, Changsheng Chen, Haosheng Huang, Huichan Lin, Jack Blanton, Chunyan Li, Francisco Andrade

Faculty Publications

The wet/dry point treatment method of FVCOM was applied to simulate the tide-induced flooding/drying process in the estuarine–tidal-creek–saltmarsh complex of the Okatee/Colleton River Estuary, South Carolina. The simulation results were compared with observed currents at three mooring sites and flooded areas observed from remote-sensing hypsometric measurements, demonstrating that FVCOM can robustly reproduce tidal and residual currents in the river and the flooding process onto the intertidal saltmarsh. The simulated flow field reveals that the Okatee/Colleton River Estuary is characterized by multiple residual eddies. Driven by the periodic tidal forcing, this estuarine system features a chaotic water transport process. Numerous residual …

Event Based Approach For Modeling Indoor Airflow Patterns, Ehsan Mousavi, Arup Bhattacharya

Faculty Publications

People spend a significant proportion of their time indoors, where the quality of indoor air affects the productivity, efficiency, and well-being of occupants. One of the oldest challenges in building construction is designing a ventilation system that ensures optimum indoor air quality. Acceptable indoor air should provide thermal comfort and minimize human exposure to contamination. Characterizing these two elements requires information on both heat/mass transfer in the microenvironment and the time-specific activity of individuals who move among these microenvironments. While researchers have utilized simulation tools to investigate this complex human-environment interaction, current numerical techniques severely limit the simulations to overly …

Ptsd Treatment Reduces Risk Of Trauma Recidivism In A Diverse Community At A Safety-Net Hospital: A Propensity Score Analysis Of Data From A Level One Trauma Center, Kaylin Beiter, Denise Danos, Erich Conrad, Stephanie Broyles, Jovanny Zabaleta, Jason Mussell, Stephen Phillippi

Population and Public Health Science Faculty Publications

Background: Physically-traumatic injuries result in PTSD for approximately 10% of Americans, and this rate is higher among individuals of color and those living in poverty. Individuals of color living in poverty experience lower access to PTSD and other mental health services. Untreated PTSD is associated with increased risk of trauma recidivism, but it is unknown if provision of treatment is actually associated with a subsequent reduction in recidivism risk. Methods: For this observational cross-sectional study, data were collected retrospectively from the Trauma Registry of a level one trauma center, safety-net hospital in New Orleans between 2018 and 2020. Receipt of …

Symplectic Effective Field Theory For Nuclear Structure Studies, D. Kekejian, J. P. Draayer, V. I. Mokeev, C. D. Roberts

Faculty Publications

A symplectic effective field theory that unveils the observed emergence of symplectic symmetry in atomic nuclei is advanced. Specifically, starting from a simple extension of the harmonic-oscillator Lagrangian, an effective field theory applied against symplectic basis states is shown to yield a Hamiltonian system with one fitted parameter. The scale of the system can be determined self-consistently as the ratio of the average volume of a nucleus assumed to be spherical to its volume as determined by the average number of oscillator quanta, which is stretched by the fact that the plane-wave solution satisfies the equations of motion at every …

Droplet Behavior In Overexpanded Supersonic Two-Phase Jets, Shyam Menon, Mohana Gurunadhan

Faculty Publications

The interaction of liquid droplets generated by spray atomization with high-speed co-flowing gas is of interest in various applications including fuel injection, spray cooling, and surface coating. The underlying processes involve interactions between the droplets themselves, and with the carrier gas. Additionally, they are influenced by shock and expansion waves present in high-speed flows, accompanied by resulting velocity and pressure fluctuations. Non-intrusive diagnostics including Shadowgraphy and Phase Doppler Particle Anemometry, along with flow simulations, are used to study droplet behavior, characterized by size and velocity changes, as a finely atomized spray is propelled by a carrier gas through a supersonic, …

Predicting Elastic Constants Of Refractory Complex Concentrated Alloys Using Machine Learning Approach, Uttam Bhandari, Hamed Ghadimi, Congyan Zhang, Shizhong Yang, Shengmin Guo

Faculty Publications

Refractory complex concentrated alloys (RCCAs) have drawn increasing attention recently owing to their balanced mechanical properties, including excellent creep resistance, ductility, and oxidation resistance. The mechanical and thermal properties of RCCAs are directly linked with the elastic constants. However, it is time consuming and expensive to obtain the elastic constants of RCCAs with conventional trial-and-error experiments. The elastic constants of RCCAs are predicted using a combination of density functional theory simulation data and machine learning (ML) algorithms in this study. The elastic constants of several RCCAs are predicted using the random forest regressor, gradient boosting regressor (GBR), and XGBoost regression …

Effects Of Hypoxia And High Temperature On Eastern Oysters: Investigating Differential Tolerance In Populations And Ploidies, Nicholas C. Coxe

LSU Master's Theses

Increasing prevalence of hypoxia in estuarine waters can pose a serious threat to eastern oysters (Crassostrea virginica). While oysters are considered more tolerant to hypoxia than many other bivalves, their tolerance at temperatures of 28 °C and above, typical in northern Gulf of Mexico estuaries in the summer, is not well characterized. Moreover, it is unknown whether differences in hypoxia tolerance exist among oyster populations or between diploid and triploid oysters. To investigate population differences, wild oysters were collected from four estuaries in the northern and northwestern Gulf of Mexico and spawned. In a series of studies, the …

Optimizing The Performance Of Parallel And Concurrent Applications Based On Asynchronous Many-Task Runtimes, Weile Wei

LSU Doctoral Dissertations

Nowadays, High-performance Computing (HPC) scientific applications often face per- formance challenges when running on heterogeneous supercomputers, so do scalability, portability, and efficiency issues. For years, supercomputer architectures have been rapidly changing and becoming more complex, and this challenge will become even more com- plicated as we enter the exascale era, where computers will exceed one quintillion cal- culations per second. Software adaption and optimization are needed to address these challenges. Asynchronous many-task (AMT) systems show promise against the exascale challenge as they combine advantages of multi-core architectures with light-weight threads, asynchronous executions, smart scheduling, and portability across diverse architectures.

In …

Hybrid Modulated-Phase-Grating For Phase Contrast X-Ray For A Varying Fringe Period Clinical Interferometry System, Elizabeth Jeong Park

LSU Master's Theses

Phase contrast x-rays are of use due to the range of imaging they can provide. Not only are they useful for attenuation they also can provide phase and small angle scatter X-ray (SAXS) information simultaneously which adds additional contrast and information to the original attention image. In prior work, a phase contrast system with Modulated Phase Grating was shown to eliminate the need for analyzer in standard Talbot Lau Xray Interferometers (TLXI). The system is clinically compatible in footprint due to its length being limited to

Accident Simulation Study For Nuclear Power Plants Impacting Louisiana, Michael D. Mcmahon

LSU Master's Theses

INTRODUCTION: Louisiana has aligned its radiological emergency program with the 2017 Environmental Protection Agency Protective Action Guides Manual, but has added a child thyroid dose evacuation threshold in lieu of distributing Potassium Iodide to the public. The nuclear power plants will continue to align with the 1992 manual for the foreseeable future, so that under some accident scenarios the state recommendations will differ from those of the utility.

OBJECTIVE: The objective of this study is to predict what accident and weather conditions will lead to a differing set of recommendations.

METHODS: More than 1000 simulations were performed of low-filtration nuclear …

Bloch Spectra For High Contrast Elastic Media, Jayasinghage Ruchira Nirmali Perera

LSU Doctoral Dissertations

The primary goal of this dissertation is to develop analytic representation formulas and power series to describe the band structure inside periodic elastic crystals made from high contrast inclusions. We use source free modes associated with structural spectra to represent the solution operator of the Lame' system inside phononic crystals. Then we obtain convergent power series for the Bloch wave spectrum using the representation formulas. An explicit bound on the convergence radius is given through the structural spectra of the inclusion array and the Dirichlet spectra of the inclusions. Sufficient conditions for the separation of spectral branches of the dispersion …

Self-Healing Composite Of Thermoset Polymer And Programmed Super Contraction Fibers, Guoqiang Li, Harper Meng

College of Engineering Patents

A composition comprising thermoset polymer, shape memory polymer to facilitate macro scale damage closure, and methods for molecular scale healing are provided. The composition can resolve structural defects by a bio-mimetic close-then heal process. In use, the shape memory polymer can provide molecular scale healing in a structural defect. The methods for molecular scale healing can include heating a composition including a thermoplastic such as fibers, particles or spheres to a level at or above the thermoplastic's melting point, then cooling of the composition below the melting temperature of the thermoplastic. The compositions have the ability to close macroscopic defects …

Self-Repelling Elastic Manifolds With Low Dimensional Range, Carl Mueller, Eyal Neumann

Journal of Stochastic Analysis

No abstract provided.

Induced Matrices: Recurrences And Markov Chains, Philip Feinsilver

Journal of Stochastic Analysis

No abstract provided.

From Equal-Mass To Extreme-Mass-Ratio Binary Inspirals: Simulation Tools For Next Generation Gravitational Wave Detectors, Samuel Douglas Cupp

LSU Doctoral Dissertations

Current numerical codes can successfully evolve similar-mass binary black holes systems, and these numerical waveforms contributed to the success of the LIGO Collaboration's detection of gravitational waves. LIGO requires high resolution numerical waveforms for detection and parameter estimation of the source. Great effort was expended over several decades to produce the numerical methods used today. However, future detectors will require further improvements to numerical techniques to take full advantage of their detection capabilities. For example, the Laser Interferometer Space Antenna (LISA) will require higher resolution simulations of similar-mass-ratio systems than LIGO. LISA will also be able to detect extreme-mass-ratio inspiral …

Influence Of Weather On Gobbling Activity Of Male Wild Turkeys, Patrick H. Wightman, James A. Martin, John C. Kilgo, Emily Rushton, Bret A. Collier, Michael J. Chamberlain

Faculty Publications

Gobbling activity of Eastern wild turkeys (Meleagris gallopavo silvestris; hereafter, turkeys) has been widely studied, focusing on drivers of daily variation. Weather variables are widely believed to influence gobbling activity, but results across studies are contradictory and often equivocal, leading to uncertainty in the relative contribution of weather variables to daily fluctuations in gobbling activity. Previous works relied on road-based auditory surveys to collect gobbling data, which limits data consistency, duration, and quantity due to logistical difficulties associated with human observers and restricted sampling frames. Development of new methods using autonomous recording units (ARUs) allows researchers to collect continuous data …

Comprehensive Analysis Of Epigenetic Clocks Reveals Associations Between Disproportionate Biological Ageing And Hippocampal Volume, Lidija Milicic, Michael Vacher, Tenielle Porter, Vincent Doré, Samantha C. Burnham, Pierrick Bourgeat, Rosita Shishegar, James Doecke, Nicola J. Armstrong, Rick Tankard, Paul Maruff, Colin L. Masters, Christopher C. Rowe, Victor L. Villemagne, Simon M. Laws, Balebail Ashok Raj, Kristin Fargher, Amanda Smith, Lisa Raudin, Gloria Chaing, Norman Relkin, Karen Elizabeth Smith, Hyungsub Shim, Laura L. Boles Ponto, Susan K. Schultz, Antero Sarrael, Raymundo Hernando, Nunzio Pomara, Dick Drost, Andrew Kertesz, John Rogers, Irina Rachinsky, Stephen Pasternak, Elizabether Finger

Clinical Research Faculty Publications

The concept of age acceleration, the difference between biological age and chronological age, is of growing interest, particularly with respect to age-related disorders, such as Alzheimer’s Disease (AD). Whilst studies have reported associations with AD risk and related phenotypes, there remains a lack of consensus on these associations. Here we aimed to comprehensively investigate the relationship between five recognised measures of age acceleration, based on DNA methylation patterns (DNAm age), and cross-sectional and longitudinal cognition and AD-related neuroimaging phenotypes (volumetric MRI and Amyloid-β PET) in the Australian Imaging, Biomarkers and Lifestyle (AIBL) and the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Significant …

Feedback Stabilization And Robustness Analysis Using Bounds On Fundamental Matrices, Frederic Mazenc, Michael Malisoff

Faculty Publications

We prove a new robust stabilization theorem for time-varying systems that have sampled measurements and time-varying disturbances, and we provide new observer designs, using novel bounds for fundamental matrices for systems with disturbances. Our main tools use properties of Metzler matrices and positive systems.

In Search Of Short Gamma-Ray Burst Optical Counterparts With The Zwicky Transient Facility, Tomás Ahumada, Shreya Anand, Michael W. Coughlin, Igor Andreoni, Erik C. Kool, Harsh Kumar, Simeon Reusch, Ana Sagués-Carracedo, Robert Stein, S. Bradley Cenko, Mansi M. Kasliwal, Leo P. Singer, Rachel Dunwoody, Joseph Mangan, Varun Bhalerao, Mattia Bulla, Eric Burns, Matthew J. Graham, David L. Kaplan, Daniel Perley, Mouza Almualla, Joshua S. Bloom, Virginia Cunningham, Kishalay De, Pradip Gatkine, Anna Y.Q. Ho, Viraj Karambelkar, Albert K.H. Kong, Yuhan Yao, G. C. Anupama, Sudhanshu Barway, Shaon Ghosh, Ryosuke Itoh

Faculty Publications

The Fermi Gamma-ray Burst Monitor (GBM) triggers on-board in response to ∼40 short gamma-ray bursts (SGRBs) per year; however, their large localization regions have made the search for optical counterparts a challenging endeavour. We have developed and executed an extensive program with the wide field of view of the Zwicky Transient Facility (ZTF) camera, mounted on the Palomar 48 inch Oschin telescope (P48), to perform target-of-opportunity (ToO) observations on 10 Fermi-GBM SGRBs during 2018 and 2020-2021. Bridging the large sky areas with small field-of-view optical telescopes in order to track the evolution of potential candidates, we look for the elusive …

The Price Of Decentralization In Cooperative Coverage Problems With Energy-Constrained Agents, Xiangyu Meng, Christos G. Cassandras, Xinmiao Sun, Kaiyuan Xu

Faculty Publications

A multiagent coverage problem is considered with energy-constrained agents, where a charging station is used to replenish an agent's energy as it becomes depleted while performing the coverage task. The objective of this article is to compare the coverage performance between centralized and decentralized approaches. To this end, a centralized coverage control method is developed to switch agents between an optimal coverage formation and an optimal charging formation. We design a controller for agent trajectories that include dwell times at the optimal coverage locations, and charging times at the charging station to maximize a coverage metric over a finite time …

New Efficient Approach To Solve Big Data Systems Using Parallel Gauss–Seidel Algorithms, Shih Yu Chang, Hsiao Chun Wu, Yifan Wang

Faculty Publications

In order to perform big-data analytics, regression involving large matrices is often necessary. In particular, large scale regression problems are encountered when one wishes to extract semantic patterns for knowledge discovery and data mining. When a large matrix can be processed in its factorized form, advantages arise in terms of computation, implementation, and data-compression. In this work, we propose two new parallel iterative algorithms as extensions of the Gauss–Seidel algorithm (GSA) to solve regression problems involving many variables. The convergence study in terms of error-bounds of the proposed iterative algorithms is also performed, and the required computation resources, namely time-and …

Co2 Zonal Injection Rate Allocation And Plume Extent Evaluation Through Wellbore Temperature Analysis, Refaat G. Hashish, Mehdi Zeidouni

Faculty Publications

Temperature analysis during a pause in injection operations, known as warmback analysis, has been used in the petroleum industry for evaluating the injection conformance and estimating the location of the flooded front in applications, such as waterflooding oil reservoirs. In this work, methods are introduced to extend the application of temperature warmback analysis to estimate the zonal CO2 injection rate and zonal CO2 plume extent during geologic CO2 storage in a saline aquifer. First, novel analytical solutions are developed to model transient temperature in the aquifer during the injection and subsequent shut-in periods considering two-phase flow (gaseous CO2 and aqueous …

Dynamics Of Polymer Melts And Polymer Nanocomposites Studied By Broadband Dielectric Spectroscopy, Mengchun Wu

LSU Doctoral Dissertations

Materials based on polymers and polymeric nanocomposites have properties advantageous for many applications. In many cases, the physical behavior is connected to molecular motion. Polymers are macromolecules in which both fast local motions and slower chain relaxations may contribute to the material properties. Answering fundamental questions on the molecular dynamics is challenging, because of the existence of many different processes and the strong temperature dependence of the processes. An investigation covering a broad window over many orders of magnitude in the time scale is needed. Hence, dielectric spectroscopy is an appropriate tool to enhance fundamental understanding. This dissertation pays special …

Producing Bacterial Cellulose From Coffee (Coffea Arabica) Kombucha Fermentation And Assessment Of Its Efficacy To Remove Pathogenic Bacteria From Contaminated Water And A Pollutant Dye From Aqueous Solution, Federico Bueno

LSU Doctoral Dissertations

Bacterial cellulose (BC), composed of cellulosic nanofibrils, is synthesized by a symbiotic culture of bacteria and yeast during the fermentation of coffee kombucha (CK). BC may be used as a purification agent and adsorbent. The overall goal of this project was to synthesize BC from CK fermentation and assess its efficacy in removing pathogenic bacteria from contaminated water and a pollutant dye from aqueous solution. The objectives of this study were to: (1) compare BCs that were produced from different carbohydrate substrates in the fermentation of CK, (2) characterize dried BCs produced using various drying methods, (3) evaluate BC as …

Characterization Of Gas Hydrate Formation And Its Impact On Slope Stability In Offshore Environments, Sulav Dhakal

LSU Doctoral Dissertations

Natural gas hydrates (NGH) are predominantly methane hydrates formed at high pressure and low temperature conditions typically in submarine sediments and permafrost. This dissertation is focused on the submarine methane hydrates formed by upward migration of free and dissolved gas. The methane gas stored within natural hydrates has more energy potential than all the combined oil and gas resources around the world. Numerical simulation of fluid flow, heat transport, and geomechanical stresses is used to characterize and evaluate the saturation, distribution, reservoir quality, and geohazards associated with hydrate-bearing sediments. Coupled thermo-hydro-mechanical (THM) simulation of hydrate formation, dissociation, and slope stability …