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Full-Text Articles in Physical Sciences and Mathematics

Effect Of Pigment Volume Concentration On Physical And Chemical Properties Of Acrylic Emulsion Paints Assessed Using Single-Sided Nmr, Mary Therese Rooney Apr 2018

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 ...


Enhancing Usability, Security, And Performance In Mobile Computing, Shanhe Yi Apr 2018

Enhancing Usability, Security, And Performance In Mobile Computing, Shanhe Yi

Dissertations, Theses, and Masters Projects

We have witnessed the prevalence of smart devices in every aspect of human life. However, the ever-growing smart devices present significant challenges in terms of usability, security, and performance. First, we need to design new interfaces to improve the device usability which has been neglected during the rapid shift from hand-held mobile devices to wearables. Second, we need to protect smart devices with abundant private data against unauthorized users. Last, new applications with compute-intensive tasks demand the integration of emerging mobile backend infrastructure. This dissertation focuses on addressing these challenges. First, we present GlassGesture, a system that improves the usability ...


Searching For A Dark Photon In The Hps Experiment, Sebouh Jacob Paul Mar 2018

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 ...


Proton Spin Structure From Monte Carlo Global Qcd Analyses, Jacob Ethier Mar 2018

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 ...


On Improving (Non)Functional Testing, Qi Luo Mar 2018

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 ...


Impacts Of Atmospheric Nitrogen Deposition And Coastal Nitrogen Fluxes On Chesapeake Bay Hypoxia, Fei Da Mar 2018

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 ...


Characterizing The Biological Impacts And Human Dimensions Of The U.S. East Coast Recreational Atlantic Bluefin Tuna Fishery, William Morris Goldsmith Jan 2018

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 ...


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 Nov 2017

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 ...


Superconducting Thin Films For The Enhancement Of Superconducting Radio Frequency Accelerator Cavities, Matthew Burton Nov 2017

Superconducting Thin Films For The Enhancement Of Superconducting Radio Frequency Accelerator Cavities, Matthew Burton

Dissertations, Theses, and Masters Projects

Bulk niobium (Nb) superconducting radio frequency (SRF) cavities are currently the preferred method for acceleration of charged particles at accelerating facilities around the world. However, bulk Nb cavities have poor thermal conductance, impose material and design restrictions on other components of a particle accelerator, have low reproducibility and are approaching the fundamental material-dependent accelerating field limit of approximately 50MV/m. Since the SRF phenomena occurs at surfaces within a shallow depth of ~1 µm, a proposed solution to this problem has been to utilize thin film technology to deposit superconducting thin films on the interior of cavities to engineer the ...


Exploiting Power For Smartphone Security And Privacy, Qing Yang Nov 2017

Exploiting Power For Smartphone Security And Privacy, Qing Yang

Dissertations, Theses, and Masters Projects

Power consumption has become a key issue for smartphone security and privacy protection. In this dissertation, we propose to exploit power for smartphone security, as well as to optimize energy consumption for smartphone privacy. First, we show that public USB charging stations pose a significant privacy risk to smartphone users. We present a side-channel attack that allows a charging station to identify which webpages are loaded while the smartphone is charging. to evaluate this side-channel, we collected power traces of Alexa top 50 websites on multiple smartphones under several conditions, including: varied battery charging level, browser cache enabled/disabled, taps ...


Modeling The Gross-Pitaevskii Equation Using The Quantum Lattice Gas Method, Armen M. Oganesov Nov 2017

Modeling The Gross-Pitaevskii Equation Using The Quantum Lattice Gas Method, Armen M. Oganesov

Dissertations, Theses, and Masters Projects

We present an improved Quantum Lattice Gas (QLG) algorithm as a mesoscopic unitary perturbative representation of the mean field Gross Pitaevskii (GP) equation for Bose–Einstein Condensates (BECs). The method employs an interleaved sequence of unitary collide and stream operators. QLG is applicable to many different scalar potentials in the weak interaction regime and has been used to model the Korteweg–de Vries (KdV), Burgers and GP equations. It can be implemented on both quantum and classical computers and is extremely scalable. We present results for 1D soliton solutions with positive and negative internal interactions, as well as vector solitons ...


Computational Methods Of Lattice Boltzmann Mhd, Christopher Robert Flint Nov 2017

Computational Methods Of Lattice Boltzmann Mhd, Christopher Robert Flint

Dissertations, Theses, and Masters Projects

Lattice Boltzmann (LB) Methods are a somewhat novel approach to Computational Fluid Dynamics (CFD) simulations. These methods simulate Navier-Stokes and magnetohydrodynamics (MHD) equations on the mesoscopic (quasi-kinetic) scale by solving for a statistical distribution of particles rather than attempting to solve the nonlinear macroscopic equations directly. These LB methods allow for a highly parallelizable code since one replaces the difficult nonlinear convective derivatives of MHD by simple linear advection on a lattice. New developments in LB have significantly extended the numerical stability limits of its applicability. These developments include multiple relaxation times (MRT) in the collision operators, maximizing entropy to ...


On The Impact Of Internet Naming Evolution: Deployment, Performance, And Security Implications, Shuai Hao Oct 2017

On The Impact Of Internet Naming Evolution: Deployment, Performance, And Security Implications, Shuai Hao

Dissertations, Theses, and Masters Projects

As one of the most critical components of the Internet, the Domain Name System (DNS) provides naming services for Internet users, who rely on DNS to perform the translation between the domain names and network entities before establishing an In- ternet connection. In this dissertation, we present our studies on different aspects of the naming infrastructure in today’s Internet, including DNS itself and the network services based on the naming infrastructure such as Content Delivery Networks (CDNs). We first characterize the evolution and features of the DNS resolution in web ser- vices under the emergence of third-party hosting services ...


Automatically Documenting Software Artifacts, Boyang Li Sep 2017

Automatically Documenting Software Artifacts, Boyang Li

Dissertations, Theses, and Masters Projects

Software artifacts, such as database schema and unit test cases, constantly change during evolution and maintenance of software systems. Co-evolution of code and DB schemas in Database-Centric Applications (DCAs) often leads to two types of challenging scenarios for developers, where (i) changes to the DB schema need to be incorporated in the source code, and (ii) maintenance of a DCAs code requires understanding of how the features are implemented by relying on DB operations and corresponding schema constraints. On the other hand, the number of unit test cases often grows as new functionality is introduced into the system, and maintaining ...


Enhancing Usability And Security Through Alternative Authentication Methods, Nicolas Jorge Van Balen Jun 2017

Enhancing Usability And Security Through Alternative Authentication Methods, Nicolas Jorge Van Balen

Dissertations, Theses, and Masters Projects

With the expanding popularity of various Internet services, online users have be- come more vulnerable to malicious attacks as more of their private information is accessible on the Internet. The primary defense protecting private information is user authentication, which currently relies on less than ideal methods such as text passwords and PIN numbers. Alternative methods such as graphical passwords and behavioral biometrics have been proposed, but with too many limitations to replace current methods. However, with enhancements to overcome these limitations and harden existing methods, alternative authentications may become viable for future use. This dissertation aims to enhance the viability ...


Disconnected Diagrams In Lattice Qcd, Arjun Singh Gambhir Jun 2017

Disconnected Diagrams In Lattice Qcd, Arjun Singh Gambhir

Dissertations, Theses, and Masters Projects

In this work, we present state-of-the-art numerical methods and their applications for computing a particular class of observables using lattice quantum chromodynamics (Lattice QCD), a discretized version of the fundamental theory of quarks and gluons. These observables require calculating so called "disconnected diagrams" and are important for understanding many aspects of hadron structure, such as the strange content of the proton. We begin by introducing the reader to the key concepts of Lattice QCD and rigorously define the meaning of disconnected diagrams through an example of the Wick contractions of the nucleon. Subsequently, the calculation of observables requiring disconnected diagrams ...


Quantum And Classical Manifestation Of Hamiltonian Monodromy, Chen Chen Jun 2017

Quantum And Classical Manifestation Of Hamiltonian Monodromy, Chen Chen

Dissertations, Theses, and Masters Projects

Integrable Hamiltonian systems are said to display nontrivial monodromy if fundamental action-angle loops defined on phase-space tori change their topological structure when the system is carried around a circuit. It was shown in earlier work that this topological change can be seen in families of trajectories of noninteracting particles; however, that work required use of a very abstract flow in phase space. In this dissertation, we show that the same topological change can occur as a result of application of ordinary forces. We also show how this dynamical phenomenon could be observed experimentally in cold atom systems. Almost everything that ...


Data-Driven Radiometric Photo-Linearization, Han Li Jun 2017

Data-Driven Radiometric Photo-Linearization, Han Li

Dissertations, Theses, and Masters Projects

In computer vision and computer graphics, a photograph is often considered a photometric representation of a scene. However, for most camera models, the relation between recorded pixel value and the amount of light received on the sensor is not linear. This non-linear relationship is modeled by the camera response function which maps the scene radiance to the image brightness. This non-linear transformation is unknown, and it can only be recovered via a rigorous radiometric calibration process. Classic radiometric calibration methods typically estimate a camera response function from an exposure stack (i.e., an image sequence captured with different exposures from ...


Deep Learning Software Repositories, Martin White Jun 2017

Deep Learning Software Repositories, Martin White

Dissertations, Theses, and Masters Projects

Bridging the abstraction gap between artifacts and concepts is the essence of software engineering (SE) research problems. SE researchers regularly use machine learning to bridge this gap, but there are three fundamental issues with traditional applications of machine learning in SE research. Traditional applications are too reliant on labeled data. They are too reliant on human intuition, and they are not capable of learning expressive yet efficient internal representations. Ultimately, SE research needs approaches that can automatically learn representations of massive, heterogeneous, datasets in situ, apply the learned features to a particular task and possibly transfer knowledge from task to ...


A Global Normal Form For Two-Dimensional Mode Conversion, David Gregory Johnston Jun 2017

A Global Normal Form For Two-Dimensional Mode Conversion, David Gregory Johnston

Dissertations, Theses, and Masters Projects

Mode conversion is a phenomenon that is of interest as a method for heating in fusion reactors. A magnetosonic wave with dispersion relation DMS propagates toward the interior of the plasma, where it excites an ion-hybrid wave with dispersion relation DIH and thereby transfers energy to the plasma. We wish to study this process using ray-based methods. The 2 2 dispersion matrix D, which is, in general, a function of the phase space variables (x; y; kx; ky), must be put into normal form, in which the diagonals of D, identied as the uncoupled dispersion relations, DMS and DIH, Poisson-commute ...


Measurement Of The Elastic Ep Cross Section At Q2 = 0.66, 1.10, 1.51 And 1.65 Gev2, Yang Wang Jun 2017

Measurement Of The Elastic Ep Cross Section At Q2 = 0.66, 1.10, 1.51 And 1.65 Gev2, Yang Wang

Dissertations, Theses, and Masters Projects

The nucleon form factors have been investigated by physicists for decades because of its fundamental importance. The world data of the proton magnetic form factor GMp shows that the measurements have been focused on Q2 lower than 5 GeV2 and it has large uncertainties at higher GeV2. Experiment E12-07-108 aims to improve the accuracy of the e − p elastic cross section to better than 2% over a Q2 range of 7 − 14 GeV2. From 2015 to 2016, the e − p elastic cross section was measured over a wide range of Q2 from 0.66 − 12.56 GeV2 at the Thomas ...


Plasmonic Approaches And Photoemission: Ag-Based Photocathodes, Zhaozhu Li Apr 2017

Plasmonic Approaches And Photoemission: Ag-Based Photocathodes, Zhaozhu Li

Dissertations, Theses, and Masters Projects

Photocathodes play an important role in present large accelerator facilities by providing polarized or un-polarized electron beams. Current state-of-art high polarization photocathodes consist of strained super-lattice GaAs based photocathodes, e.g. GaAs/GaAsP has a quantum efficiency ~1% and polarization ~90% at near-infrared wavelength for the incident light. Despite the advantages offered by metallic photocathodes regarding longer life time, fast response time and low requirements of ultra-high vacuum environment, they have not been put to use due to their low quantum efficiency, even though one can envision several approaches to achieve spin-polarization from them. A possible solution is to apply ...


Investigation Of Local Structures In Cation-Ordered Microwave Dielectric A Solid-State Nmr And First Principle Calculation Study, Rony Gustam Kalfarisi Mar 2017

Investigation Of Local Structures In Cation-Ordered Microwave Dielectric A Solid-State Nmr And First Principle Calculation Study, Rony Gustam Kalfarisi

Dissertations, Theses, and Masters Projects

Solid-state Nuclear Magnetic Resonance (ssNMR) spectroscopy has proven to be a powerful method to probe the local structure and dynamics of a system. In powdered solids, the nuclear spins experience various anisotropic interactions which depend on the molecular orientation. These anisotropic interactions make ssNMR very useful as they give a specific appearance to the resonance lines of the spectra. The position and shape of these resonance lines can be related to local structure and dynamics of the system under study. My research interest has focused around studying local structures and dynamics of quadrupolar nuclei in materials using ssNMR spectroscopy. $^7 ...


Workload Prediction For Efficient Performance Isolation And System Reliability, Ji Xue Mar 2017

Workload Prediction For Efficient Performance Isolation And System Reliability, Ji Xue

Dissertations, Theses, and Masters Projects

In large-scaled and distributed systems, like multi-tier storage systems and cloud data centers, resource sharing among workloads brings multiple benefits while introducing many performance challenges. The key to effective workload multiplexing is accurate workload prediction. This thesis focuses on how to capture the salient characteristics of the real-world workloads to develop workload prediction methods and to drive scheduling and resource allocation policies, in order to achieve efficient and in-time resource isolation among applications. For a multi-tier storage system, high-priority user work is often multiplexed with low-priority background work. This brings the challenge of how to strike a balance between maintaining ...


Optical Control Of Multi-Photon Coherent Interactions In Rubidium Atoms, Gleb Vladimirovich Romanov Mar 2017

Optical Control Of Multi-Photon Coherent Interactions In Rubidium Atoms, Gleb Vladimirovich Romanov

Dissertations, Theses, and Masters Projects

In the last few decades, coherent light-atom interactions have opened unprecedented possibilities for the coherent control of atomic and optical quantum systems, paved the way for the practical realization of quantum information technologies, and allowed for the creation of novel quantum-enhanced sensors. This dissertation investigates the interaction of multiple near-resonant optical fields with hot rubidium atoms under the conditions of electromagnetically induced transparency. The main goal of the presented research is to address some fundamental challenges in using such systems for practical applications. The EIT effect relies on the strong coupling of an optical probe field and a collective long-lived ...


Computational Studies Of Strongly Correlated Quantum Matter, Hao Shi Mar 2017

Computational Studies Of Strongly Correlated Quantum Matter, Hao Shi

Dissertations, Theses, and Masters Projects

The study of strongly correlated quantum many-body systems is an outstanding challenge. Highly accurate results are needed for the understanding of practical and fundamental problems in condensed-matter physics, high energy physics, material science, quantum chemistry and so on. Our familiar mean-field or perturbative methods tend to be ineffective. Numerical simulations provide a promising approach for studying such systems. The fundamental difficulty of numerical simulation is that the dimension of the Hilbert space needed to describe interacting systems increases exponentially with the system size. Quantum Monte Carlo (QMC) methods are one of the best approaches to tackle the problem of enormous ...


An Investigation Of Power Saving And Privacy Protection On Smartphones, Dachuan Liu Mar 2017

An Investigation Of Power Saving And Privacy Protection On Smartphones, Dachuan Liu

Dissertations, Theses, and Masters Projects

With the advancements in mobile technology, smartphones have become ubiquitous in people's daily lives and have greatly facilitated users in many aspects. For a smartphone user, power saving and privacy protection are two important issues that matter and draw serious attentions from research communities. In this dissertation, we present our studies on some specific issues of power saving and privacy protection on a smartphone. Although IEEE 802.11 standards provide Power Save Mode (PSM) to help mobile devices conserve energy, PSM fails to bring expected benefits in many real scenarios. We define an energy conserving model to describe the ...


Enhancing Energy Efficiency And Privacy Protection Of Smart Devices, Ge Peng Mar 2017

Enhancing Energy Efficiency And Privacy Protection Of Smart Devices, Ge Peng

Dissertations, Theses, and Masters Projects

Smart devices are experiencing rapid development and great popularity. Various smart products available nowadays have largely enriched people’s lives. While users are enjoying their smart devices, there are two major user concerns: energy efficiency and privacy protection. In this dissertation, we propose solutions to enhance energy efficiency and privacy protection on smart devices. First, we study different ways to handle WiFi broadcast frames during smartphone suspend mode. We reveal the dilemma of existing methods: either receive all of them suffering high power consumption, or receive none of them sacrificing functionalities. to address the dilemma, we propose Software Broadcast Filter ...


Formulating Schwinger-Dyson Equations For Qed Propagators In Minkowski Space, Shaoyang Jia Mar 2017

Formulating Schwinger-Dyson Equations For Qed Propagators In Minkowski Space, Shaoyang Jia

Dissertations, Theses, and Masters Projects

The Schwinger-Dyson equations (SDEs) are coupled integral equations for the Green's functions of a quantum field theory (QFT). The SDE approach is the analytic nonperturbative method for solving strongly coupled QFTs. When applied to QCD, this approach, also based on first principles, is the analytic alternative to lattice QCD. However, the SDEs for the n-point Green's functions involves (n+1)-point Green's functions (sometimes (n+2)-point functions as well). Therefore any practical method for solving this infinitely coupled system of equations requires a truncation scheme. When considering strongly coupled QED as a modeling of QCD, naive ...


Determination Of The Kinematics Of The Qweak Experiment And Investigation Of An Atomic Hydrogen Møller Polarimeter, Valerie Marie Gray Feb 2017

Determination Of The Kinematics Of The Qweak Experiment And Investigation Of An Atomic Hydrogen Møller Polarimeter, Valerie Marie Gray

Dissertations, Theses, and Masters Projects

The Qweak experiment has tested the Standard Model through making a precise measurement of the weak charge of the proton (QpW). This was done through measuring the parity-violating asymmetry for polarized electrons scattering off of unpolarized protons. The parity-violating asymmetry measured is directly proportional to the four-momentum transfer (Q^2) from the electron to the proton. The extraction of QpW from the measured asymmetry requires a precise Q^2 determination. The Qweak experiment had a Q^2 = 24.8 ± 0.1 m(GeV^2) which achieved the goal of an uncertainty of ≤ 0.5%. From the measured asymmetry and Q ...