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Articles 1 - 30 of 41
Full-Text Articles in Physical Sciences and Mathematics
Exploring New Paradigms For Mobile Edge Computing, Yutao Tang
Exploring New Paradigms For Mobile Edge Computing, Yutao Tang
Dissertations, Theses, and Masters Projects
Edge computing has been rapidly growing in recent years to meet the surging demands from mobile apps and Internet of Things (IoT). Similar to the Cloud, edge computing provides computation, storage, data, and application services to the end-users. However, edge computing is usually deployed at the edge of the network, which can provide low-latency and high-bandwidth services for end devices. So far, edge computing is still not widely adopted. One significant challenge is that the edge computing environment is usually heterogeneous, involving various operating systems and platforms, which complicates app development and maintenance. in this dissertation, we explore to combine …
Probe Of Electroweak Interference Effects In Non-Resonant Inelastic Electron-Proton Scattering, James Franklyn Dowd
Probe Of Electroweak Interference Effects In Non-Resonant Inelastic Electron-Proton Scattering, James Franklyn Dowd
Dissertations, Theses, and Masters Projects
The Qweak collaboration at Jefferson Lab made the first direct measurement of the proton's weak charge, Q_W^p, via a measurement of the parity-violating asymmetry in elastic e ⃑p scattering with low four-momentum transfer. to meet the high-precision goals, energy-dependent electroweak radiative corrections were applied to the measured asymmetry. The γZ box, □_γZ, where a photon and a Z-boson are simultaneously exchanged, was the most problematic of these corrections. It could not be calculated through the same perturbative methods as the rest of the corrections. The □_γZ correction depends on theoretical models of the γZ interference structure functions, F_1,2^γZ, for which …
Development Of Large-Scale Unstructured Grid Storm Surge And Sub-Grid Inundation Models For Coastal Applications, Zhuo Liu
Dissertations, Theses, and Masters Projects
Storm surge and inundation induced by hurricanes and nor'easters pose a profound threat to coastal communities and ecosystems. These storm events with powerful winds, heavy precipitation, and strong wind waves can lead to major flooding for cities along U.S. Coasts. Recent examples of Hurricane Irene (2011) in North Carolina and Virginia and Hurricane Sandy (2012) in New York City not only demonstrated the immense destructive power by the storms, but also revealed the obvious, crucial need for improved forecasting of storm tide and inundation. in part I, a large-scale unstructured-grid 3-D barotropic storm tide model SCHISM (Semi-implicit Cross-scale Hydroscience Integrated …
Impact Of Submerged Aquatic Vegetation On Water Quality In Cache Slough Complex, Sacramento-San Joaquin Delta: A Numerical Modeling Study, Xun Cai
Dissertations, Theses, and Masters Projects
Submerged aquatic vegetation (SAV) plays a significant role in many aquatic systems, and impacts both physical and ecological quantities. It can baffle currents, attenuate waves, recycle nitrogen and phosphorus from the sediment bed, perform ecosystem function as a primary producer, and provide critical habitat for many aquatic species. Conversely, the invasive SAV, Egeria densa (Brazilian waterweed), in the San Francisco Bay & Delta has been a nuisance since its introduction into the system in the 1960s. It has displaced most of the native submersed aquatic plant species in the Delta and restructured the ecosystem, thus threatening the survival of several …
Exotic Phases In Attractive Fermions: Charge Order, Pairing, And Topological Signatures, Peter Rosenberg
Exotic Phases In Attractive Fermions: Charge Order, Pairing, And Topological Signatures, Peter Rosenberg
Dissertations, Theses, and Masters Projects
Strongly interacting many-body systems remain a central challenge of modern physics. Recent developments in the field of ultra-cold atomic physics have opened a new window onto this enduring problem. Experimental progress has revolutionized the approach to studying many-body systems and the exotic behaviors that emerge in these systems. It is now possible to engineer and directly measure a variety of models that can capture the essential features of real materials without the added complexity of disorder, impurities, or complicated or irregular geometries. The parameters of these models can be freely tuned with tremendous precision. These experimental realizations are an ideal …
Quantifying And Explaining Causal Effects Of World Bank Aid Projects, Jianing Simulation Zhao
Quantifying And Explaining Causal Effects Of World Bank Aid Projects, Jianing Simulation Zhao
Dissertations, Theses, and Masters Projects
In recent years, machine learning methods have enabled us to predict with good precision using large training data, such as deep learning. However, for many problems, we care more about causality than prediction. For example, instead of knowing that smoking is statistically associated with lung cancer, we are more interested in knowing that smoking is the cause of lung cancer. With causality, we can understand how the world progresses and how impacts are made on an outcome by influencing the cause. This thesis explores how to quantify the causal effects of a treatment on an observable outcome in the presence …
Computational Investigations Of The Structure And Spectroscopy Of Small Biomolecules In The Gas Phase, Zachary Michael Smith
Computational Investigations Of The Structure And Spectroscopy Of Small Biomolecules In The Gas Phase, Zachary Michael Smith
Dissertations, Theses, and Masters Projects
Small biomolecule systems were interrogated using infrared multiple photon dissociation (IRMPD) action spectroscopy and corresponding quantum chemical calculations with a particular focus on peptide fragmentation and protonation site preference. b2+ and b3+ fragment ions with a terminal lysine homolog residue were investigated using IRMPD in the fingerprint region (1000 cm-1 – 2000 cm-1) and a variety of computational methods. We present the first spectroscopic confirmation of b-ion formation with a lactam structure. Infrared spectra for b2+ fragment system indicate the presence of a mixture of structures, though final determination will require further investigation. The b3+ fragment ion infrared spectra show …
A Measurement Of Nuclear Effects In Deep Inelastic Scattering In Neutrino-Nucleus Interactions, Anne Norrick
A Measurement Of Nuclear Effects In Deep Inelastic Scattering In Neutrino-Nucleus Interactions, Anne Norrick
Dissertations, Theses, and Masters Projects
Neutrino-Nucleus Deep Inelastic Scattering (DIS) events provide a probe into the structure of nucleons within a nucleus that cannot be accessed via charged lepton-nucleus interactions. The MINERvA experiment is stationed in the Neutrinos from the Main Injector (NuMI) beam line at Fermi National Accelerator Laboratory. With the recent increase in average neutrino energy and the greatly increased intensity of the NuMI beam line, projected sensitivities for DIS cross section ratio analyses using MINERvA's suite of nuclear targets (C, CH, Fe and Pb) are greatly increased. an analysis of theMINERvA DIS data on carbon, iron, lead, and plastic has been conducted …
Dynamics Of Systems With Hamiltonian Monodromy, Daniel Salmon
Dynamics Of Systems With Hamiltonian Monodromy, Daniel Salmon
Dissertations, Theses, and Masters Projects
A system is said to have monodromy if, when we carry the system around a closed circuit, it does not return to its initial state. The simplest example is the square-root function in the complex plane. A Hamiltonian system is said to have Hamiltonian monodromy if its fundamental action-angle loops do not return to their initial topological state at the end of a closed circuit. These changes in topology of angle loops carry through to other aspects of these systems, including the classical dynamics of families of trajectories, quantum spectra and even wavefunctions. This topological change in the evolution of …
Extensions Of The Standard Model Higgs Sector, Richard Keith Thrasher
Extensions Of The Standard Model Higgs Sector, Richard Keith Thrasher
Dissertations, Theses, and Masters Projects
The Standard Model is regarded as one of the most successful scientific theories, but there is compelling evidence that it is an incomplete theory of particle physics. There is currently no understanding of the observed baryon asymmetry, the nature of dark matter, and dark energy. Field theoretic considerations indicate parameters in the Standard Model are extremely fine-tuned. This suggests the existence of new physics, accessible at higher energies, to explain these seemingly unnatural tunings. to solve these puzzles, and others not addressed by the Standard Model, many extensions of the Standard Model have been proposed. It is of great importance …
Investigating Emerging Security Threats In Clouds And Data Centers, Xing Gao
Investigating Emerging Security Threats In Clouds And Data Centers, Xing Gao
Dissertations, Theses, and Masters Projects
Data centers have been growing rapidly in recent years to meet the surging demand of cloud services. However, the expanding scale of a data center also brings new security threats. This dissertation studies emerging security issues in clouds and data centers from different aspects, including low-level cooling infrastructures and different virtualization techniques such as container and virtual machine (VM). We first unveil a new vulnerability called reduced cooling redundancy that might be exploited to launch thermal attacks, resulting in severely worsened thermal conditions in a data center. Such a vulnerability is caused by the wide adoption of aggressive cooling energy …
Usability, Efficiency And Security Of Personal Computing Technologies, Nancy Carter
Usability, Efficiency And Security Of Personal Computing Technologies, Nancy Carter
Dissertations, Theses, and Masters Projects
New personal computing technologies such as smartphones and personal fitness trackers are widely integrated into user lifestyles. Users possess a wide range of skills, attributes and backgrounds. It is important to understand user technology practices to ensure that new designs are usable and productive. Conversely, it is important to leverage our understanding of user characteristics to optimize new technology efficiency and effectiveness. Our work initially focused on studying older users, and personal fitness tracker users. We applied the insights from these investigations to develop new techniques improving user security protections, computational efficiency, and also enhancing the user experience. We offer …
Understanding And Enriching Randomness Within Resource-Constrained Devices, Kyle Wallace
Understanding And Enriching Randomness Within Resource-Constrained Devices, Kyle Wallace
Dissertations, Theses, and Masters Projects
Random Number Generators (RNG) find use throughout all applications of computing, from high level statistical modeling all the way down to essential security primitives. A significant amount of prior work has investigated this space, as a poorly performing generator can have significant impacts on algorithms that rely on it. However, recent explosive growth of the Internet of Things (IoT) has brought forth a class of devices for which common RNG algorithms may not provide an optimal solution. Furthermore, new hardware creates opportunities that have not yet been explored with these devices. in this Dissertation, we present research fostering deeper understanding …
Evaluation Of Population Structure And The Interspecific Relationship Of Striped Marlin (Kajikia Audax) And White Marlin (K. Albida) Based On Traditional Or Genome-Wide Molecular Markers, Nadya Mamoozadeh
Dissertations, Theses, and Masters Projects
The istiophorid billfishes (marlins, spearfishes, and sailfish) are highly migratory pelagic fishes exhibiting broad and continuous spatial distributions in the Atlantic, Pacific, and Indian oceans. These species are targeted by a number of recreational, commercial, artisanal, and subsistence fisheries worldwide, and are also caught as bycatch in pelagic longline fisheries targeting tunas and swordfish. Though stock assessments have not been conducted for all istiophorids, assessments available for some species indicate that many istiophorid stocks are overfished and/or experiencing overfishing. However, the development of stock-specific recovery efforts is often impeded by a lack of information on basic species biology, including stock …
Surface-Enhanced Raman Spectroscopy Studies Of Organic Dyes For Art Conservation And Ph Sensing Applications, Shelle Nicholle Butler
Surface-Enhanced Raman Spectroscopy Studies Of Organic Dyes For Art Conservation And Ph Sensing Applications, Shelle Nicholle Butler
Dissertations, Theses, and Masters Projects
Surface-enhanced Raman scattering (SERS) spectroscopy is a powerful analytical technique with widespread applications. In this work, SERS applications in the realms of art conservation and biosensing are reviewed. First, the theory of this unambiguous and ultrasensitive technique is explained. Next, a review of the pedagogical journey in art conservation research through the lenses of undergraduates is offered in Chapter 2, a chapter recently submitted to the American Chemical Society. Finally, an investigation in biosensing SERS is explored with developing a SERS pH sensitive probe while offering new insight into SERS capabilities and the relationship between analyte and nanoparticle.
Iron Polypyridyl Catalysts Assembled On Metal Oxide Semiconductors For Heterogeneous Photocatalytic Hydrogen Generation, Nicholas Race
Iron Polypyridyl Catalysts Assembled On Metal Oxide Semiconductors For Heterogeneous Photocatalytic Hydrogen Generation, Nicholas Race
Dissertations, Theses, and Masters Projects
Artificial Photosynthesis (AP) provides a promising method for the conversion of solar energy to chemical fuel in the form of H2 and O2. Development of heterogeneous systems in which H2 evolution catalysts are immobilized on metal oxide semiconductors is imperative for the large-scale implementation of AP systems. This research focuses on the immobilization of an active H2 evolution catalyst on large band gap semiconductors for the development and optimization of a highly active photocatalytic H2 generation system.
Ratiometric Fluorescent Sensors In Aqueous Environments, Matthew August Mccarron
Ratiometric Fluorescent Sensors In Aqueous Environments, Matthew August Mccarron
Dissertations, Theses, and Masters Projects
Conjugated polymer nanoparticles (CPN) doped with a mercury sensitive dye are able to detect ion concentrations as low as a parts-per-billion within an aqueous environment. Select forms of spirolatam rhodamine dye are capable of selectively undergoing a ring-opening reaction in response to Hg2+ ions. The initial closed form presents as a colorless, non-fluorescent, compound while the opened form results in a colored and highly fluorescent form. The CPNs are also fluorescent, yet at a lower wavelength and can transfer of their energy into the dye molecules via Förster resonance energy transfer. The dye’s reaction with Hg2+ goes unhindered by the …
Effect Of Pigment Volume Concentration On Physical And Chemical Properties Of Acrylic Emulsion Paints Assessed Using Single-Sided Nmr, Mary Therese Rooney
Effect Of Pigment Volume Concentration On Physical And Chemical Properties Of Acrylic Emulsion Paints Assessed Using Single-Sided Nmr, Mary Therese Rooney
Dissertations, Theses, and Masters Projects
Acrylic emulsion paint is one of the most common media employed by 20th century painters. Since early acrylic paintings have begun to require the attention of conservators, scientists are working to characterize the properties of these paints to facilitate conservation efforts. In this study, we report an investigation of the physical and chemical properties of acrylic emulsion paints using single-sided NMR in conjunction with gloss measurements and scanning electron microscopy coupled with energy dispersive spectrometry. Combining the data from these techniques gives insight into pigment-binder interactions and the acrylic curing process, showing that as pigment concentration is increased in paints, …
Searching For A Dark Photon In The Hps Experiment, Sebouh Jacob Paul
Searching For A Dark Photon In The Hps Experiment, Sebouh Jacob Paul
Dissertations, Theses, and Masters Projects
The Heavy Photon Search (HPS) experiment at Jefferson Lab is designed to search for a hypothesized elementary particle called a dark (heavy) photon. Such a particle would behave as a mediator between dark matter and the Standard Model through a kinetic mixing with the Standard Model’s photon. The search is performed by scattering GeV-scale electrons off tungsten nuclei in a fixed target and looking for a resonance and/or displaced vertices amidst a background of radiative QED trident events. These background events are kinematically identical to the events in which dark photons are produced and decay into lepton pairs. Several other …
Proton Spin Structure From Monte Carlo Global Qcd Analyses, Jacob Ethier
Proton Spin Structure From Monte Carlo Global Qcd Analyses, Jacob Ethier
Dissertations, Theses, and Masters Projects
Although significant progress has been made in recent years in understanding the composition of the proton's spin from its quark and gluon constituents, a complete picture has yet to emerge. Such information is encoded in spin-dependent parton distribution functions (PDFs) that, as a consequence of being inherently nonperturbative, must be extracted through global QCD analyses of polarized lepton-nucleon and proton-proton collisions. Experiments that measure a final state hadron from these reactions are particularly useful for separating the individual quark and anti-quark polarizations, but require knowledge of parton-to-hadron fragmentation functions (FFs) to describe theoretically. In this thesis, we present a new …
On Improving (Non)Functional Testing, Qi Luo
On Improving (Non)Functional Testing, Qi Luo
Dissertations, Theses, and Masters Projects
Software testing is commonly classified into two categories, nonfunctional testing and functional testing. The goal of nonfunctional testing is to test nonfunctional requirements, such as performance and reliability. Performance testing is one of the most important types of nonfunctional testing, one goal of which is to detect the phenomena that an Application Under Testing (AUT) exhibits unexpectedly worse performance (e.g., lower throughput) with some input data. During performance testing, a critical challenge is to understand the AUT’s behaviors with large numbers of combinations of input data and find the particular subset of inputs leading to performance bottlenecks. However, enumerating those …
Assessing The Impact Of Land Use And Climate Change On Streamflow And Nutrient Delivery To The New River Estuary, Nc, Shanna Williamson
Assessing The Impact Of Land Use And Climate Change On Streamflow And Nutrient Delivery To The New River Estuary, Nc, Shanna Williamson
Dissertations, Theses, and Masters Projects
Freshwater inflow influences numerous physical, chemical, and biological characteristics of estuaries. The influx of freshwater to an estuary typically serves as an important source of allochthonous material from which primary producers derive their energy and transfer this energy to higher trophic levels. Any changes to freshwater flow subsequently impacts nutrient delivery and indirectly impacts organisms across multiple trophic levels. Anthropogenic changes to coastal land use and climate both act to threaten the integrity of estuarine systems by influencing freshwater inflow and dissolved nutrient input. Watershed loading models such as the Regional Nutrient Management (ReNuMa) model offer the ability to estimate …
Characterizing The Biological Impacts And Human Dimensions Of The U.S. East Coast Recreational Atlantic Bluefin Tuna Fishery, William Morris Goldsmith
Characterizing The Biological Impacts And Human Dimensions Of The U.S. East Coast Recreational Atlantic Bluefin Tuna Fishery, William Morris Goldsmith
Dissertations, Theses, and Masters Projects
Atlantic bluefin tuna (Thunnus thynnus) are targeted by recreational anglers along the east coast of the United States, and the fishery is thought to be of considerable economic value. However, limited knowledge of the preferences and values of fishery participants impedes the ability of managers to maximize fishery benefits and predict harvest patterns, while an incomplete understanding of post-release mortality hinders efforts to estimate total mortality resulting from the fishery. This dissertation used a multidisciplinary approach that relied heavily on cooperative research with the recreational fishing community to examine these questions. A stated choice survey of private anglers permitted to …
Crab Larval Abundance And Settlement Patterns In A Changing Chesapeake Bay, Itchika Sivaipram
Crab Larval Abundance And Settlement Patterns In A Changing Chesapeake Bay, Itchika Sivaipram
Dissertations, Theses, and Masters Projects
All estuarine crabs have two larval stages, the zoea and the megalopa. Zoeae are entirely planktonic, whereas megalopae begin as plankton before beginning to search for settlement substrates as late stage megalopae. At both stages, crab larvae are subject to environmental conditions of the estuary. With changing environmental conditions due to anthropogenic activities and climate change, an understanding of how these planktonic larvae respond to environmental conditions is necessary for understanding subsequent larval supply to benthic populations and implication for fisheries management and habitat restoration. For this dissertation, I: 1) analyzed long-term timeseries in the lower Chesapeake Bay for spatial …
Radiation Shielding Bricks For Mars Using Martian Regolith Simulant And Hydrogen-Rich Polymers, Sara Sargent
Radiation Shielding Bricks For Mars Using Martian Regolith Simulant And Hydrogen-Rich Polymers, Sara Sargent
Dissertations, Theses, and Masters Projects
Radiation shielding materials are an essential component of long-term space travel and habitation. The mission to Mars will require a radiation shielding material that can be produced on Mars through energy and cost-efficient means. in this study, Martian regolith simulant and hydrogen-rich polymers are used to create a radiation shielding material in the form of bricks. The bricks are capable of shielding against galactic cosmic radiation on Mars. There are three methods in which the bricks were formed: 1) a heated press, 2) a microwave oven in a CO2 atmosphere, and 3) a vacuum oven with a low CO2 pressure. …
Developing Efficient High-Order Transport Schemes For Cross-Scale Coupled Estuary-Ocean Modeling, Fei Ye
Developing Efficient High-Order Transport Schemes For Cross-Scale Coupled Estuary-Ocean Modeling, Fei Ye
Dissertations, Theses, and Masters Projects
Geophysical fluid dynamics (GFD) models have progressed greatly in simulating the world’s oceans and estuaries in the past three decades, thanks to the development of novel numerical algorithms and the advent of massively parallel high-performance computing platforms. Study of inter-related processes on multi-scales (e.g., between large-scale (remote) processes and small-scale (local) processes) has always been an important theme for GFD modeling. For this purpose, models based on unstructured-grid (UG) have shown great potential because of their superior abilities in enabling multi-resolution and in fitting geometry and boundary. Despite UG models’ successful applications on coastal systems, significant obstacles still exist that …
The Development And Proliferation Of Summer Algal Blooms In The Oligo/Poly-Haline Portion Of The Chesapeake Bay - Observational And Numerical Modeling Studies, Zhengui Wang
Dissertations, Theses, and Masters Projects
Algal blooms occur annually in many parts of the Chesapeake Bay. The causes of algal blooms are complex and can be different in different regions. In this study, we will conduct data analysis for the observed data and adopt various methods to investigate algal bloom phenomenon in three separate regions in the oligo/poly-haline portion of the Bay. Chapter 1 provides a general introduction of the algal bloom research in the Chesapeake Bay. In Chapter 2, an observational analysis and a numerical study on the algal blooms in Back River were conducted. A hypothesis was made that high pH can trigger …
Impacts Of Atmospheric Nitrogen Deposition And Coastal Nitrogen Fluxes On Chesapeake Bay Hypoxia, Fei Da
Impacts Of Atmospheric Nitrogen Deposition And Coastal Nitrogen Fluxes On Chesapeake Bay Hypoxia, Fei Da
Dissertations, Theses, and Masters Projects
Although rivers are the primary source of dissolved inorganic nitrogen (DIN) inputs to the Chesapeake Bay, direct atmospheric DIN deposition and DIN fluxes from the continental shelf can also significantly impact Chesapeake Bay hypoxia. The relative role of these additional sources of DIN has not previously been thoroughly quantified. In this study, the three-dimensional Estuarine-Carbon-Biogeochemistry model embedded in the Regional Ocean Modeling System (ChesROMS-ECB) is used to examine the relative impact of these three DIN sources. Model simulations highlight that DIN inputs from the atmosphere have roughly the same impact on hypoxia as the same gram for gram change in …
Monitoring Infection Of E. Coli By Bacteriophage T7 Through Mass Spectrometry-Based Proteomics, Amy Swayne Schienschang
Monitoring Infection Of E. Coli By Bacteriophage T7 Through Mass Spectrometry-Based Proteomics, Amy Swayne Schienschang
Dissertations, Theses, and Masters Projects
Mass spectrometry-based proteomics has become an important and versatile tool in analytical chemistry, making sense of complex biological samples and shedding light on the intricate proteomes of living organisms. Bottom-up proteomics studies are used to elucidate the changes in gene expression of bacteriophage T7 over the course of infection of Escherichia coli. E. coli cultures were infected with T7, sampled over time, and proteins were isolated and enzymatically digested. Nanoflow liquid chromatography combined with tandem mass spectrometry was used to detect proteolytic peptides and identify host and phage proteins. Generally, phage proteins were detected on a time scale fitting the …
Consumption Patterns Of Chesapeake Bay Fishes, Christopher James Sweetman
Consumption Patterns Of Chesapeake Bay Fishes, Christopher James Sweetman
Dissertations, Theses, and Masters Projects
As fisheries management moves away from single-species approaches and towards more holistic, ecosystem-based approaches, physiological and ecological interactions need to be explicitly considered and mechanistically understood. Accurate portrayals of food web interactions and the direction and magnitude of energy flow between predator and prey populations are fundamental components to further develop ecosystem-based fisheries management (EBFM). to bolster information that is required within an EBFM framework in the Chesapeake Bay, I conducted research designed to advance traditional dietary studies and better understand the form and structure within the Bay's food web. This research relied on controlled feeding experiments, comprehensive sampling of …