Physical Sciences and Mathematics Commons^™

Distributions Of Euphausia Superba, Euphausia Crystallorophias, And Pleuragramma Antarcticum With Correlations To Environmental Variables In The Western Ross Sea, Antarctica, Linnea Brynn Davis

OES Theses and Dissertations

Antarctic krill (Euphausia superba), crystal krill (Euphausia crystallorophias), and Antarctic silverfish (Pleuragramma antarcticum) are key mid-trophic level species in the Ross Sea food web that provide connectivity between primary production and the upper trophic levels. Distributions of these species were constructed from net-based and acoustic observations collected in the western Ross Sea from 1988-2004. Distributions of environmental conditions in the Ross Sea were obtained from a high-resolution circulation model (temperature, mixed layer depth, surface speed) and satellite-derived observations (chlorophyll, sea ice cover). These distributions were analyzed with a range of statistical methods to determine …

Investigation Of Multi-Photon Excitation In Argon With Applications In Hypersonic Flow Diagnostics, Jack L. Mills

Physics Theses & Dissertations

Non-intrusive flow diagnostics are essential for studying the physics of hypersonic flow wake regions. To advance the development of next generation hypersonic vehicles and to improve computational fluid dynamics techniques in the hypersonic regime, NASA needs a suitable non-intrusive diagnostic technique to measure velocity, density, and temperature. We will present our work on developing a seedless, non-intrusive diagnostic technique using excited state argon atoms, prepared via multi-photon excitation. In this dissertation, we report results on the first phase of this hypersonic wake measurement project. In particular, we have redesigned and characterized the performance of a high energy, nanosecond pulsed Ti:Sapphire …

Multiple Imputation Of Missing Data In Structural Equation Models With Mediators And Moderators Using Gradient Boosted Machine Learning, Robert J. Milletich Ii

Psychology Theses & Dissertations

Mediation and moderated mediation models are two commonly used models for indirect effects analysis. In practice, missing data is a pervasive problem in structural equation modeling with psychological data. Multiple imputation (MI) is one method used to estimate model parameters in the presence of missing data, while accounting for uncertainty due to the missing data. Unfortunately, commonly used MI methods are not equipped to handle categorical variables or nonlinear variables such as interactions. In this study, we introduce a general MI framework that uses the Bayesian bootstrap (BB) method to generate posterior inferences for indirect effects and gradient boosted machine …

Potential Impacts Of Climate Change On Photochemistry Of Zostera Marina L., Billur Celebi

OES Theses and Dissertations

Seagrasses account for approximately 10% of the ocean’s total carbon storage, although photosynthesis of seagrasses is carbon limited at today’s oceanic pH. Therefore, increasing atmospheric CO₂ concentration, which results in ocean acidification/carbonation, is predicted to have a positive impact on seagrass productivity. Previous studies have confirmed the positive influence of increasing CO₂ on photosynthesis and survival of the temperate eelgrass Zostera marina L., but the acclimation of photoprotective mechanisms in this context has not been characterized. This study aimed to quantify the long-term impacts of ocean acidification on photochemical control mechanisms that promote photosynthesis while simultaneously protecting …

Electroproduction Of Neutral Pion Off Helium-4, Bayram Torayev

Physics Theses & Dissertations

Deeply virtual exclusive processes offer a unique opportunity to study the internal structure of the nucleon and nuclei. The goal of this work is to extract the beam-spin asymmetry in deeply virtual coherent neutral pion electroproduction, e⁴He → e′⁴He′π⁰, using the CLAS detector in the experimental Hall B at Thomas Jefferson National Accelerator Facility. The data were collected in 2009 with a 6 GeV longitudinally polarized electron beam impinging on a 30 cm long, 6 atm Helium-4 gaseous target. In order to ensure that the process is coherent, a new Radial Time Projection Chamber …

Changing Trends In Wave Heights In The U.S. Mid-Atlantic Region, Hillary Lane

Civil & Environmental Engineering Theses & Dissertations

The pace and effects of climate change are an area of constant focus for coastal engineers as evolving patterns in the atmosphere worldwide affect the oceans and coasts on a regional and global scale. Surface waves respond to changing wind patterns both locally and from propagating swell, and the difficulty in predicting future wind patterns is well-established. Expectations that climate change will result in more frequent and intense coastal storms and consequently greater wave heights in the North Atlantic are still unrealized, and recent forecasts from a variety of atmosphere-ocean coupled global climate models instead predict decreasing wave heights through …

Effects Of Surrounding Water Table On A Forested Wetland Habitat In East Coast Of Virginia, Lane Stokes

Civil & Environmental Engineering Theses & Dissertations

Exchanges into and out of a wetland, including surface water flow, groundwater flow, and constituents in the flows, usually determine the wetland physicochemical characteristics and biodiversity. To date, of these three exchanges, groundwater flow is the least studied, particularly in the United States of America. In this thesis, field observations were conducted at a forested non-tidal wetland, located on a flat hilltop. The position of the wetland is such that groundwater outflow is the only significant exchange that could be impacted by the surrounding land use. In addition, a spatially variable steady-state model was set up to extrapolate the observations …

Longitudinal Tidal Dispersion Coefficient Estimation And Total Suspended Solids Transport Characterization In The James River, Beatriz Eugenia Patino

Civil & Environmental Engineering Theses & Dissertations

The longitudinal dispersion coefficient is a parameter used to evaluate the effect of cross-sectional variations on substance mixing mechanisms in estuaries influenced by tide, wind and internal density variations. Considering a two dimensional approach, this study aims at evaluating a tidal area of the lower James River at approximately 19 miles upstream from the mouth at the Chesapeake Bay, in the City of Newport News, and applies an experimental procedure based on in-situ salinity concentrations to estimate the dispersion coefficient in the area where receives a discharge from the HRSD James River Wastewater Treatment Plant, and further characterizes Total Suspended …

Bioenergetics: Experimental Demonstration Of Excess Protons And Related Features, Haitham A. Saeed

Chemistry & Biochemistry Theses & Dissertations

Over the last 50 years, ever since the Nobel-prize work of Peter Mitchell’s Chemiosmotic theory, the question whether bioenergetics energy transduction occurs through localized or delocalized protons has been a controversial issue among scientists. Recently, a proton-electrostatics localization hypothesis was formulated which may provide a new and clear understanding of localized and delocalized proton-coupling energy transduction in many biological systems. The aim of this dissertation was to test this new hypothesis.

To demonstrate the fundamental behavior of localized protons in a pure water-membrane-water system in relation to the newly derived pmf equation, excess protons and excess hydroxyl anions were generated …

Robust Algorithms For Estimating Vehicle Movement From Motion Sensors Within Smartphones, Ilyas Ustun

Computational Modeling & Simulation Engineering Theses & Dissertations

Building sustainable traffic control solutions for urban streets (e.g., eco-friendly signal control) and highways requires effective and reliable sensing capabilities for monitoring traffic flow conditions so that both the temporal and spatial extents of congestion are observed. This would enable optimal control strategies to be implemented for maximizing efficiency and for minimizing the environmental impacts of traffic. Various types of traffic detection systems, such as inductive loops, radar, and cameras have been used for these purposes. However, these systems are limited, both in scope and in time. Using GPS as an alternative method is not always viable because of problems …

Forward Light Scattering In An Extended Sample Of Cold Atoms, Stetson Roof

Physics Theses & Dissertations

We present results on the forward emitted light from a cold atomic sample of 87Rb. Specifically,we study single-photon superradiance which is characterized by a rapid decay faster than the single atom lifetime with the light preferentially emitted in the forward direction. Additionally, we report measurements on its counterpart, the cooperative Lamb shift. The results are interpreted using microscopic light scattering theory as well as techniques from classical optics. The comparison of the two analytical techniques provides a new perspectiveon what is meant by cooperative and collective scattering effects in cold atomic physics.

Emergence Of Collective Light Scattering In Atomic 87Rb Samples, Kasie Jean Kemp

Physics Theses & Dissertations

Over the past half century, atomic ensembles have been used to create sensors, clocks, and quantum information systems. As these devices become more compact, and as the number of atoms increases to improve the sensitivity for detection, the atomic samples are increasing in density and optical depth. As such, the spectroscopic properties of the atomic media are modified due to interactions among the particles in the ensemble. We report investigation of near-resonance light scattering from a cold atomic sample of 87Rb. Initially prepared in a magneto-optical trap, the atoms are loaded into a far-off-resonance optical dipole trap (FORT) in which …

Discoloration Of A Green Pigment In Tintoretto’S Allegorical Figure Of Spring And Analysis Of The Chemical Properties And Stability Of Copper Resinate, Sarah Wells Conner Horn

Chemistry & Biochemistry Theses & Dissertations

The focus of this thesis is the discoloration of a common historical green pigment, copper resinate. In this research the discoloration was investigated in Jacopo Tintoretto’s painting, Allegorical Figure of Spring, painted c. 1555. This painting is believed to have been painted with copper resinate which has discolored to brown over the centuries. The state of repair of the painting was determined using visual analysis under visible and UV light and the use of copper green pigments was confirmed using energy-dispersive X-ray fluorescence, including copper resinate based upon supplementary historical evidence. Substantial evidence was found from visual inspection and …

Possible Sources And Impacts Of Biochar Water Extractable Organic Compounds On Aquatic Microorganisms, Cameron Russell Smith

Chemistry & Biochemistry Theses & Dissertations

Smokeless biomass pyrolysis with application of biochar as a soil amendment could be a significant approach for carbon sequestration to possibly control climate change for energy and environmental sustainability. If biochar were to be utilized as a soil amendment and a carbon sequestration agent at Gt C scales, the release of potentially toxic compounds into soils and associated hydrological systems, through soil rainwater runoff and leaching, might have negative consequences, in both agro-ecosystems and aquatic environmental systems. Therefore, the main focus of this dissertation was to study the sources and chemical composition of biochar water extractable (soluble) organic compounds and …

Magnopark, Smart Parking Detection Based On Cellphone Magnetic Sensor, Maryam Arab

Computer Science Theses & Dissertations

We introduce a solution that uses the availability of heavy crowds and their smart devices, to gain more result as to where potential parking is possible. By leveraging the raw magnetometer, gyroscope, and accelerometer data, we are able to detect parking spots through the natural movement exerted by the walking pedestrians on the sidewalks beside the streets. Dating back as far as 2013, a very large portion of pedestrians composing the crowds on the sidewalk, possessed at least one smart device in their hand or pocket14]. It is this statistic that fuels our application, in which we depend on crowds …

Discipline-Based Planetary Education Research And Computational Fluid Dynamics Analysis Of Mars, Filis Coba

Physics Theses & Dissertations

This thesis originates from the testing and implementation of an IRB-approved interactive animation designed to help students understand what causes The Reasons For The Seasons (RFTS) on Earth. Results from the testing indicated a small improvement in student understanding after exposure to the animation. Next, using the 3-D mapping tool Google Earth, students explored seasons and other planetary features on Mercury, Venus, the Moon and Mars through IRB-approved interactive tours which were developed and tested for astronomy education. Results from the tests indicated that there were statistically significant learning gains (p-value < 0.05) after students interacted with the tours compared to those who did not. The development of the tours inspired a geophysics study of the possibility of former plate motion (or plate tectonics) on Mars. A 2-D finite element convection model for the mantle of Mars was designed and solved using COMSOL Multiphysics 5.1, to investigate whether or not thermal gradients in a Mars-sized planet could cause vigorous upper mantle convection, consistent with plate tectonic processes. Results from this project indicated that stable convection could occur in the interior of a Mars-like planet assuming the presence of sufficiently high thermal gradients at about 0.8 times the mantle temperature of Earth. The convective patterns resembled hot upwelling and cool downwelling which may be similar to subduction-like features. Furthermore, increasing the temperature of the hot boundaries resulted in faster, more rigorous convective motions and a hotter average temperature.

Computational Modeling Of Facial Response For Detecting Differential Traits In Autism Spectrum Disorders, Manar D. Samad

Electrical & Computer Engineering Theses & Dissertations

This dissertation proposes novel computational modeling and computer vision methods for the analysis and discovery of differential traits in subjects with Autism Spectrum Disorders (ASD) using video and three-dimensional (3D) images of face and facial expressions. ASD is a neurodevelopmental disorder that impairs an individual’s nonverbal communication skills. This work studies ASD from the pathophysiology of facial expressions which may manifest atypical responses in the face. State-of-the-art psychophysical studies mostly employ na¨ıve human raters to visually score atypical facial responses of individuals with ASD, which may be subjective, tedious, and error prone. A few quantitative studies use intrusive sensors on …

Machine Learning Methods For Medical And Biological Image Computing, Rongjian Li

Computer Science Theses & Dissertations

Medical and biological imaging technologies provide valuable visualization information of structure and function for an organ from the level of individual molecules to the whole object. Brain is the most complex organ in body, and it increasingly attracts intense research attentions with the rapid development of medical and bio-logical imaging technologies. A massive amount of high-dimensional brain imaging data being generated makes the design of computational methods for efficient analysis on those images highly demanded. The current study of computational methods using hand-crafted features does not scale with the increasing number of brain images, hindering the pace of scientific discoveries …

A Hybrid Tabu/Scatter Search Algorithm For Simulation-Based Optimization Of Multi-Objective Runway Operations Scheduling, Bulent Soykan

Engineering Management & Systems Engineering Theses & Dissertations

As air traffic continues to increase, air traffic flow management is becoming more challenging to effectively and efficiently utilize airport capacity without compromising safety, environmental and economic requirements. Since runways are often the primary limiting factor in airport capacity, runway operations scheduling emerge as an important problem to be solved to alleviate flight delays and air traffic congestion while reducing unnecessary fuel consumption and negative environmental impacts. However, even a moderately sized real-life runway operations scheduling problem tends to be too complex to be solved by analytical methods, where all mathematical models for this problem belong to the complexity class …

Reevaluating The Geologic Formations Of The Upper Coastal Plain In Chesterfield County, South Carolina, Bradley Aaron Fitzwater

OES Theses and Dissertations

Data from a new geological map of the Patrick, S.C. 7.5 minute quadrangle (1:24,000) and detailed descriptions of two cores collected nearby (Middendorf and Cheraw, S.C.) permit improved interpretation of the geology of this portion of the Carolina Sandhills. Geologic mapping incorporated analyses of outcrops with LiDAR data, soil survey maps, ground-penetrating radar transects, and hand auger borings. Micro- and macrofossil identification and optically-stimulated luminescence (OSL) dating provided age control.

Four distinct mappable units occur throughout the Patrick quadrangle. Resting unconformably on schist of the Paleozoic Persimmons Fork Formation, the Cretaceous Middendorf Formation is more than 85.3 m thick and …

A Computational Framework For Learning From Complex Data: Formulations, Algorithms, And Applications, Wenlu Zhang

Computer Science Theses & Dissertations

Many real-world processes are dynamically changing over time. As a consequence, the observed complex data generated by these processes also evolve smoothly. For example, in computational biology, the expression data matrices are evolving, since gene expression controls are deployed sequentially during development in many biological processes. Investigations into the spatial and temporal gene expression dynamics are essential for understanding the regulatory biology governing development. In this dissertation, I mainly focus on two types of complex data: genome-wide spatial gene expression patterns in the model organism fruit fly and Allen Brain Atlas mouse brain data. I provide a framework to explore …

Hotspots, Extinction Risk And Conservation Priorities Of Greater Caribbean And Gulf Of Mexico Marine Bony Shorefishes, Christi Linardich

Biological Sciences Theses & Dissertations

Understanding the status of species is important for allocation of resources to redress biodiversity loss. Regional organizations tasked with managing threats to the 1,360 marine bony shorefishes of the Caribbean and Gulf of Mexico would benefit from a delineation of conservation priorities. However, prior to this study, conservation status was known for only one quarter of these shorefishes. Extinction risk assessment under IUCN Red List Criteria is a widely-used, objective method to communicate species-specific conservation needs. Data were collated on each species’ distribution, population, habitats and threats and experts at three Red List workshops assigned a global level extinction risk …

Defining The Competencies, Programming Languages, And Assessments For An Introductory Computer Science Course, Simon Sultana

STEMPS Theses & Dissertations

The purpose of this study was to define the competencies, programming languages, and assessments for an introductory computer science course at a small private liberal arts university. Three research questions were addressed that involved identifying the competencies, programming languages, and assessments that academic and industry experts in California’s Central Valley felt most important and appropriate for an introduction to computer science course.

The Delphi methodology was used to collect data from the two groups of experts with various backgrounds related to computing. The goal was to find consensus among the individual groups to best define aspects that would best comprise …

Novel Monte Carlo Methods For Large-Scale Linear Algebra Operations, Hao Ji

Computer Science Theses & Dissertations

Linear algebra operations play an important role in scientific computing and data analysis. With increasing data volume and complexity in the "Big Data" era, linear algebra operations are important tools to process massive datasets. On one hand, the advent of modern high-performance computing architectures with increasing computing power has greatly enhanced our capability to deal with a large volume of data. One the other hand, many classical, deterministic numerical linear algebra algorithms have difficulty to scale to handle large data sets.

Monte Carlo methods, which are based on statistical sampling, exhibit many attractive properties in dealing with large volume of …

Development Of Visualization-Animation Software For Learning Transportation Algorithms, Ivan P. Makohon

Computational Modeling & Simulation Engineering Theses & Dissertations

Recognizing the steady decline in US Science Technology Engineering Mathematics (STEM) interests and enrollments, the National Science Foundation (NSF) and the White House have developed national strategies and provided significant budget resources to STEM education research [1-2] in the past years, with the ultimate goals being to improve both the quality and number of highly trained US educators, student workforce in STEM topics, in today’s highly competitive global markets. With the explosion of the internet’s capability and availability, it is even more critical to effectively train this future USA-STEM work-force and/or to develop effective STEM related teaching tools to reach …

Machine Learning Methods For Brain Image Analysis, Ahmed Fakhry

Computer Science Theses & Dissertations

Understanding how the brain functions and quantifying compound interactions between complex synaptic networks inside the brain remain some of the most challenging problems in neuroscience. Lack or abundance of data, shortage of manpower along with heterogeneity of data following from various species all served as an added complexity to the already perplexing problem. The ability to process vast amount of brain data need to be performed automatically, yet with an accuracy close to manual human-level performance. These automated methods essentially need to generalize well to be able to accommodate data from different species. Also, novel approaches and techniques are becoming …

Toward Open And Programmable Wireless Network Edge, Mostafa Uddin

Computer Science Theses & Dissertations

Increasingly, the last hop connecting users to their enterprise and home networks is wireless. Wireless is becoming ubiquitous not only in homes and enterprises but in public venues such as coffee shops, hospitals, and airports. However, most of the publicly and privately available wireless networks are proprietary and closed in operation. Also, there is little effort from industries to move forward on a path to greater openness for the requirement of innovation. Therefore, we believe it is the domain of university researchers to enable innovation through openness. In this thesis work, we introduce and defines the importance of open framework …

A Simulation-Based Layered Framework Framework For The Development Of Collaborative Autonomous Systems, Ioannis Sakiotis

Computational Modeling & Simulation Engineering Theses & Dissertations

The purpose of this thesis is to introduce a simulation-based software framework that facilitates the development of collaborative autonomous systems. Significant commonalities exist in the design approaches of both collaborative and autonomous systems, mirroring the sense, plan, act paradigm, and mostly adopting layered architectures. Unfortunately, the development of such systems is intricate and requires low-level interfacing which significantly detracts from development time. Frameworks for the development of collaborative and autonomous systems have been developed but are not flexible and center on narrow ranges of applications and platforms. The proposed framework utilizes an expandable layered structure that allows developers to define …

Towards Aggregating Time-Discounted Information In Sensor Networks, Xianping Wang

Computer Science Theses & Dissertations

Sensor networks are deployed to monitor a seemingly endless list of events in a multitude of application domains. Through data collection and aggregation enhanced with data mining and machine learning techniques, many static and dynamic patterns can be found by sensor networks. The aggregation problem is complicated by the fact that the perceived value of the data collected by the sensors is affected by many factors such as time, location and user valuation. In addition, the value of information deteriorates often dramatically over time. Through our research, we already achieved some results:

A formal algebraic analysis of information discounting, especially …

Analysis Off Dependent Discrete Choices Using Gaussian Copula, Arjun Poddar

Mathematics & Statistics Theses & Dissertations

A popular tool for analyzing product choices of consumers is the well-known conditional logit discrete choice model. Originally publicized by McFadden (1974), this model assumes that the random components of the underlying latent utility functions of the consumers follow independent Gumbel distributions. However, in practice the independence assumption may be violated and a more reasonable model should account for the dependence of the utilities. In this dissertation we use the Gaussian copula with compound symmetric and autoregressive of order one correlation matrices to construct a general multivariate model for the joint distribution of the utilities. The induced correlations on the …