Physical Sciences and Mathematics Commons^™

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 (SBF). …

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 truncation schemes violate various principles of the …

Shining Light On The Phase Transitions Of Vanadium Dioxide, Tyler J. Huffman

Dissertations, Theses, and Masters Projects

The salient feature of the familiar structural transition accompanying the thermally-driven metal-insulator transition in bulk vanadium dioxide (VO2) is a pairing of all the vanadium ions in the monoclinic M¬1 insulating phase. Whether this pairing (unit cell doubling) alone is sufficient to open the energy gap has been the central question of a classic debate which has continued for almost sixty years. Interestingly, there are two less familiar insulating states, monoclinic M2 and triclinic, which are accessible via strain or chemical doping. These phases are noteworthy in that they exhibit distinctly different V-V pairing. With infrared and optical photon spectroscopy, …

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^2 , QpW was determined to …

Parsing The Aggregation- And Photodegradation-Induced Effects Of Rhodamine-Sensitized Tio2 And Zro2 Films, James Cassidy

Dissertations, Theses, and Masters Projects

The impact of rhodamine aggregates on the photophysical properties of rhodamine dyes adsorbed to TiO2 were investigated using diffuse reflectance spectroscopy, steady-state fluorescence, and time-correlated single photon counting (TCSPC). Photocatalyzed de-alkylation of rhodamine dyes containing tertiary amine groups (5-ROX, R101, and RB) was observed on TiO2, which resulted in a ~50 nm hypsochromic shift. Therefore, concentration dependent diffuse reflectance spectra of R560/TiO2 samples, which contained primary amines, demonstrated the formation of H- and J-aggregates at the expense of the monomers. The formation of J-aggregates resulted in FRET between monomers and J-aggregates which yielded a bathochromic shifted fluorescence spectra as a …

Using Water Quality Models In Management - A Multiple Model Assessment, Analysis Of Confidence, And Evaluation Of Climate Change Impacts, Isaac Irby

Dissertations, Theses, and Masters Projects

Human impacts on the Chesapeake Bay through increased nutrient run-off as a result of land-use change, urbanization, and industrialization, have resulted in a degradation of water quality over the last half-century. These direct impacts, compounded with human-induced climate changes such as warming, rising sea-level, and changes in precipitation, have elevated the conversation surrounding the future of water quality in the Bay. The overall goal of this dissertation project is to use a combination of models and data to better understand and quantify the impact of changes in nutrient loads and climate on water quality in the Chesapeake Bay. This research …

Using High-Resolution Glider Data And Biogeochemical Modeling To Investigate Phytoplankton Variability In The Ross Sea, Daniel Edward Kaufman

Dissertations, Theses, and Masters Projects

As Earth’s climate changes, polar environments experience a disproportionate share of extreme shifts. Because the Ross Sea shelf has the highest annual productivity of any Antarctic continental shelf, this region is of particular interest when striving to characterize current and future changes in Antarctic systems. However, understanding of mesoscale variability of biogeochemical patterns in the Ross Sea and how this variability affects assemblage dynamics is incomplete. Furthermore, it is unknown how the Ross Sea may respond to projected warming, reduced summer sea ice concentrations, and shallower mixed layers during the next century. to investigate these dynamics and explore their consequences …

The Role Of Seabed Resuspension On Oxygen And Nutrient Dynamics In Coastal Systems: A Numerical Modeling Study, Julia Miege Moriarty

Dissertations, Theses, and Masters Projects

Seabed resuspension can impact organic matter fate and water column biogeochemistry in coastal environments. Cycles of erosion and deposition can, for example, affect remineralization rates, seabed-water column fluxes of dissolved oxygen and nutrients, and light attenuation. Yet, models that incorporate both sediment transport and biogeochemical processes are rare, and nearly all neglect the effect of resuspension on oxygen and nutrient dynamics. Development of a novel tool, i.e. a coupled hydrodynamic-sediment transport-biogeochemical model, allowed for an investigation of the role of resuspension on oxygen and nitrogen dynamics within three distinct coastal environments. Called HydroBioSed, the coupled model was built within the …

Highly-Correlated Electron Behavior In Niobium And Niobium Compound Thin Films, Melissa R. Beebe

Dissertations, Theses, and Masters Projects

Electron correlations are the root of many interesting phenomena in materials, including phase transitions such as superconductivity and insulator-to-metal transitions, which are of great interest both for scientific understanding and for many applications. Such phase transitions can often be tailored in thin films, in which the geometry of the material is limited in one dimension. By studying how the physical structure of a thin film affects its correlated electron response, it is possible to obtain useful insight into both the nature of the electron correlations present in the material and how to control them for various applications. Niobium, an elemental …

Synthesis Of [2.2.2]-Diazabicyclic Alkaloids: I: Diels-Alder Reactions Of A C2-Carboxy Pyrazinone & Ii: Intermolecular Diels-Alder Reaction Of A Proline Derived Pyrazinone With Symmetric Dienophiles, Jonathan Clarence Perkins

Dissertations, Theses, and Masters Projects

[2.2.2]-Diazabicyclic alkaloids are a natural product family with diverse biological activities. The development of a synthetic methods towards the synthesis of [2.2.2]-diazabicyclic alkaloids is described. I: Diels-Alder Reactions of a C2-Carboxy Pyrazinone Using an N-heterocyclic carbene catalyzed aroylation of a proline 3,5-dichloropyrazinone, a synthetic route to C2-carboxy pyrazinones was developed to study the intermolecular and intramolecular Diels-Alder reactions of these compounds to form the bicyclo[2.2.2]diazaoctane core. Studies showed that having oxidation present α to the pyrazinone ring did not provide any significant increase in reactivity or selectivity as compared to pyrazinones without oxidation α to the ring. In some cases, …

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 and …

Extensions And Applications Of Mean Length Mortality Estimators For Assessment Of Data-Limited Fisheries, Quang C. Huynh

Dissertations, Theses, and Masters Projects

For data-limited fisheries, length-based mortality estimators are attractive as alternatives to age-structured models due to the simpler data requirements and ease of use of the former. This dissertation develops new extensions of mean length-based mortality estimators and applies them to federally-managed stocks in the southeastern U.S. and U.S. Caribbean.

Chapter 1 presents a review of length-based methods from the literature. Common themes regarding the methodology, assumptions, and diagnostics in these length-based methods are discussed. In Chapter 2, a simulation study evaluates the performance of the length-converted catch curve (LCCC), Beverton-Holt equation (BHE), and Length Based-Spawner Potential Ratio (LB-SPR) over a …

Reconstructing Coastal Forest Retreat And Marsh Migration Response To Historical Sea Level Rise, Nathalie Schieder

Dissertations, Theses, and Masters Projects

Climate change assessments predict that rates of relative sea level rise will increase in the future, leading to enhanced inundation of low-lying coastal regions and a 20 – 50 % decline in salt marsh area by 2100. Global sea level rise began accelerating in the late 19th to early 20th century, and local rates along the U.S. mid-Atlantic coast are twice as fast as global estimates. Frequent flooding and salt stress associated with sea level rise lead to coastal transgression, and the survival of ecosystems depends on their ability to migrate inland faster than they erode and submerge. Here, I …

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. Li …

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 …

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 …

Ecosystem Services Of Restored Oyster Reefs In A Chesapeake Bay Tributary: Abundance And Foraging Of Estuarine Fishes, Bruce William Pfirrmann

Dissertations, Theses, and Masters Projects

Oyster reef restoration may enhance the production of ecologically or economically important fish species, an ecosystem service, by providing refuge and foraging habitat. Predicting the effects of oyster habitat restoration on fisheries production in Chesapeake Bay requires a better understanding of fish habitat use, trophic dynamics, and the processes leading to production on a habitat-scale. The objective of this thesis was to evaluate the influence of restored subtidal oyster reefs on the abundance and foraging patterns of mobile estuarine fishes. Specifically, I compared the 1) abundance, 2) stomach fullness, 3) diet composition, and 4) daily consumption rate of fishes collected …

Impact Of Climate Variation And Human Adaptation On The Physical Transport Processes And Water Exchange In Chesapeake Bay, Jiabi Du

Dissertations, Theses, and Masters Projects

The efficiencies of water exchanges in both vertical and horizontal directions reflect the overall impact of various physical processes and serve as important indicators of physical control over a variety of ecological and biogeochemical processes. The vertical exchange between surface layers and bottom layers of a waterbody has proved to exert great control over the hypoxic condition, while the horizontal exchange between an estuary and coastal ocean determines the flushing capacity of the estuary and the retention rate of riverine materials. Various processes, such as tidal flushing, tidal mixing, gravitational circulation, and lateral circulation, can affect water exchange. Therefore, water …

Investigating The Charge-Transfer Dynamics Of Single-Molecule Sensitizers, Jenna Tan

Dissertations, Theses, and Masters Projects

Dye-sensitized solar cells (DSSCs) can reduce the cost of photovoltaic electricity generation to meet global energy needs. Optimizing DSSC efficiency requires a detailed understanding of the underlying charge transfer processes at the dye-semiconductor interface. By modifying the sensitizer structure, we gain insight into these charge transfer mechanisms. In this thesis, two hydroxyanthraquinone dyes are compared to investigate the impact of structure on charge-transfer and photobleaching dynamics. A combination of ensemble-averaged and single-molecule spectroscopy approaches are used to interpret the underlying ET kinetics.

Impact Of Climate Change Variables On Nutrient Cycling By Marine Microorganisms In The Southern California Bight And Ross Sea, Antarctica, Jenna Lee Spackeen

Dissertations, Theses, and Masters Projects

Ocean environments are being impacted by climate warming, elevated carbon dioxide (CO2) levels, and shifting nutrient sources and sinks. It is essential to quantify the sensitivity of microorganisms to these effects of global change because they form the base of the marine food web and are an integral component of nutrient cycling on the planet. their role in photosynthesis, nutrient uptake, and transfer of organic matter into higher trophic levels or to the deep ocean via the biological pump render microorganisms key in ecosystem structure and function and in regulating the global climate. The goal of this dissertation research was …

Ac Zeeman Force With Ultracold Atoms, Charles Fancher

Dissertations, Theses, and Masters Projects

Ultracold atom experiments use a gas of neutral atoms with temperatures less than 100 µK above absolute zero and offer unmatched experimental control of quantum states and coherence, which has allowed ultracold atom-based measurements to be some of the most precise to date. While ultracold atom experiments can control almost all atomic degrees of freedom, spin-dependent trapping and spatial manipulation has remained difficult if not inaccessible. We are developing a method of spin-dependent trapping and spatial manipulation for ultracold neutral atoms using the AC Zeeman force produced by a microwave magnetic near-field gradient generated by an atom chip. We measure …

Physical Properties Of Traditional And Water-Miscible Oil Paints As Assessed By Single-Sided Nmr, Nicholas Anthony Sanchez Udell

Dissertations, Theses, and Masters Projects

Single-sided NMR has been demonstrated as a useful technique for the inexpensive and non-invasive study of cultural heritage objects, including numerous different painting and paint samples. The relatively recent invention of water-miscible oil paints – a new form of environmentally friendly oil paint that can be thinned and cleaned by water – provides a need for analysis of the physical properties of the cured paint films. Single-sided NMR offers an excellent analytical tool to study the structural effects of the emulsifying agent present in water-miscible oil paints on the paint linoxyn network by measuring the transverse (T2) relaxation times for …

An Improved Measurement Of The Muon Neutrino Charged Current Quasi-Elastic Cross-Section On Hydrocarbon At Minerva, Dun Zhang

Dissertations, Theses, and Masters Projects

Neutrino interactions in the detectors of long baseline oscillation experiments are analyzed to determine the neutrino flavor and energy spectrum, allowing the neutrino mass ordering and mixing parameters to be determined. For neutrino interactions below the pion production threshold, the dominant reaction is charged current quasi-elastic (CCQE) scattering. Oscillation experiments are made of heavy nuclei so the QE process occurs on nucleons that are embedded in the nuclear environment. Predictions of the QE cross-section suffer from significant uncertainties due to our understanding of that nuclear environment and the way it is probed by the weak interaction. I have developed a …

Studies Of Respiratory Rhythm Generation Maintained In Organotypic Slice Cultures, Wiktor Samuel Phillips

Dissertations, Theses, and Masters Projects

Breathing is an important rhythmic motor behavior whose underlying neural mechanisms can be studied in vitro. The study of breathing rhythms in vitro has depended upon reduced preparations of the brainstem that both retain respiratory-active neuronal populations and spontaneously generate respiratory-related motor output from cranial and spinal motor nerves. Brainstem-spinal cord en bloc preparations and transverse medullary slices of the brainstem have greatly improved the ability of researchers to experimentally access and thus characterize interneurons important in respiratory rhythmogenesis. These existing in vitro preparations are, however, not without their limitations. For example, the window of time within which experiments may …

Electron Neutrino Appearance In The Nova Experiment, Ji Liu

Dissertations, Theses, and Masters Projects

The NuMI off-Axis $\nu_e$ Appearance (NO$\nu$A) experiment is a long baseline, off-axis neutrino oscillation experiment. It is designed to search for oscillations of $\nu_\mu$ to $\nu_e$ by comparing measurements of the NuMI beam composition in two detectors. These two detectors are functionally identical, nearly fully-active liquid-scintillator tracking calorimeters and located at two points along the beam line to observe the neutrinos. The Near Detector (ND), situated \unit[1]{km} away from the proton target at Fermilab, measures neutrinos prior to oscillation. Then the Far Detector (FD), located 810 km away at Ash River, Minnesota, measures the neutrinos after they have traveled and …

Rethinking Privacy And Security Mechanisms In Online Social Networks, Xin Ruan

Dissertations, Theses, and Masters Projects

With billions of users, Online Social Networks(OSNs) are amongst the largest scale communication applications on the Internet. OSNs enable users to easily access news from local and worldwide, as well as share information publicly and interact with friends. On the negative side, OSNs are also abused by spammers to distribute ads or malicious information, such as scams, fraud, and even manipulate public political opinions. Having achieved significant commercial success with large amount of user information, OSNs do treat the security and privacy of their users seriously and provide several mechanisms to reinforce their account security and information privacy. However, the …

Developmental, Physiological, And Transcriptomic Analyses Of Neurons Involved In The Generation Of Mammalian Breathing, Andrew Kottick

Dissertations, Theses, and Masters Projects

Breathing is a rhythmic motor behavior with obvious physiological importance: breathing movements are essential for respiration, which sustains homeostasis and life itself in a wide array of animals including humans and all mammals. The breathing rhythm is produced by interneurons of the brainstem preBötzinger complex (preBötC) whose progenitors express the transcription factor Dbx1. However, the cellular and synaptic neural mechanisms underlying respiratory rhythmogenesis remain unclear. The first chapter of this dissertation examines a Dbx1 transgenic mouse line often exploited to study the neural control of breathing. It emphasizes the cellular fate of progenitors that express Dbx1 at different times during …

Matrix Results And Techniques In Quantum Information Science And Related Topics, Diane Christine Pelejo

Dissertations, Theses, and Masters Projects

In this dissertation, we present several matrix-related problems and results motivated by quantum information theory. Some background material of quantum information science will be discussed in chapter 1, while chapter 7 gives a summary of results and concluding remarks. In chapter 2, we look at $2^n\times 2^n$ unitary matrices, which describe operations on a closed $n$-qubit system. We define a set of simple quantum gates, called controlled single qubit gates, and their associated operational cost. We then present a recurrence scheme to decompose a general $2^n\times 2^n$ unitary matrix to the product of no more than $2^{n-1}(2^n-1)$ single qubit gates …

Enhancing The Sensing Capabilities Of Mobile And Embedded Systems, Daniel George Graham

Dissertations, Theses, and Masters Projects

In this work, we aim to develop new sensors and sensing platforms that facilitate the development of new mobile and embedded devices. Mobile and embedded devices have become an integral part of our everyday lives and the sensing capabilities of these devices have improved throughout the years. Developing new and innovative sensors and sensing platforms will provide the building blocks for developing new sensing systems. In an effort to facilitate these innovations we have developed two new in-air sonar sensors and a new reconfigurable sensing platform. The first in-air sonar sensor is designed for ranging applications and uses the phone's …

Workload Interleaving With Performance Guarantees In Data Centers, Feng Yan

Dissertations, Theses, and Masters Projects

In the era of global, large scale data centers residing in clouds, many applications and users share the same pool of resources for the purposes of reducing energy and operating costs, and of improving availability and reliability. Along with the above benefits, resource sharing also introduces performance challenges: when multiple workloads access the same resources concurrently, contention may occur and introduce delays in the performance of individual workloads. Providing performance isolation to individual workloads needs effective management methodologies. The challenges of deriving effective management methodologies lie in finding accurate, robust, compact metrics and models to drive algorithms that can meet …