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Articles 31 - 60 of 60
Full-Text Articles in Physical Sciences and Mathematics
The Minimum Number Of Multiplicity 1 Eigenvalues Among Real Symmetric Matrices Whose Graph Is A Tree, Wenxuan Ding
The Minimum Number Of Multiplicity 1 Eigenvalues Among Real Symmetric Matrices Whose Graph Is A Tree, Wenxuan Ding
Undergraduate Honors Theses
For a tree T, U(T) denotes the minimum number of eigenvalues of multiplicity 1 among all real symmetric matrices whose graph is T. It is known that U(T) >= 2. A tree is linear if all its vertices of degree at least 3 lie on a single induced path, and k-linear if there are k of these high degree vertices. If T′ is a linear tree resulting from the addition of 1 vertex to T, we show that |U(T′)−U(T)|
Blockchain In Healthcare: A New Perspective From Social Media Data, Andrew Caietti
Blockchain In Healthcare: A New Perspective From Social Media Data, Andrew Caietti
Undergraduate Honors Theses
Blockchain as a technology has brought with it a wave of promises and expectations. After its successes in the financial sector, many potential new applications of the technology have been theorized across a variety of sectors. Blockchain’s application to healthcare stands out among these theories. Healthcare is a sector that views technological innovation under more scrutiny, so the introduction of blockchain into healthcare is a particularly unique implementation of the technology. Attempting to understand how blockchain is accepted in the healthcare industry is a difficult problem due to the nature of data associated with the sector. One avenue to understand …
Epidemic Spread Modeling For Covid-19 Using Hard Data, Anna Schmedding
Epidemic Spread Modeling For Covid-19 Using Hard Data, Anna Schmedding
Dissertations, Theses, and Masters Projects
We present an individual-centric model for COVID-19 spread in an urban setting. We first analyze patient and route data of infected patients from January 20, 2020 ,to May 31, 2020, collected by the Korean Center for Disease Control & Prevention (KCDC) and illustrate how infection clusters develop as a function of time. This analysis offers a statistical characterization of mobility habits and patterns of individuals. We use this characterization to parameterize agent-based simulations that capture the spread of the disease, we evaluate simulation predictions with ground truth, and we evaluate different what-if counter-measure scenarios. Although the presented agent-based model is …
Recruitment And Post-Settlement Mortality Of The Soft-Shell Clam, Mya Arenaria, Shantelle Landry
Recruitment And Post-Settlement Mortality Of The Soft-Shell Clam, Mya Arenaria, Shantelle Landry
Dissertations, Theses, and Masters Projects
The soft-shell clam, Mya arenaria, is a benthic, filter-feeding, infaunal clam typically found in intertidal and shallow subtidal waters. Chesapeake Bay stocks of M. arenaria have been depleted since the 1960s due to various factors including predation, temperature, low recruitment, habitat loss, disease mortalities, and commercial harvest. As an important prey item for many commercial species, low abundances of these clams are mostly the result of the voracious appetite of the blue crab, Callinectes sapidus. In addition to predation, summer water temperatures in the Chesapeake Bay are likely driving the low abundances of M. arenaria, as water temperatures commonly surpass …
Proton Spin Structure From Simultaneous Monte Carlo Global Qcd Analysis, Yiyu Zhou
Proton Spin Structure From Simultaneous Monte Carlo Global Qcd Analysis, Yiyu Zhou
Dissertations, Theses, and Masters Projects
Despite the great effort and achievements made towards understanding proton spin structure in the past few decades, a complete picture is still elusive. Parton distribution functions (PDFs), which in quantum chromodynamics (QCD) encode the momentum and helicity distributions of quarks and gluons inside a proton, provide the means by which to quantify the proton structure information. Being inherently nonperturbative, PDFs have to be extracted from unpolarized and polarized lepton-hadron and hadron-hadron scattering data. In particular, experiments that measure unpolarized and polarized jet observables can provide insight into the momentum and helicity distributions of gluons, which have generally been more difficult …
Combining Performance Profiling And Modeling For Accuracy And Efficiency, Hao Xu
Combining Performance Profiling And Modeling For Accuracy And Efficiency, Hao Xu
Dissertations, Theses, and Masters Projects
Modern computer systems have evolved to employ powerful parallel architectures, including multi-core processors, multi-socket chips, large memory subsystems, and fast network communication. Given such powerful hardware, developers rely on performance profiling and modeling to guide their performance optimization. However, performance optimization is facing new challenges on efficiency and accuracy with emerging computer systems. In this dissertation, we propose approaches to address these challenges. We first study memory contention in Non-Uniform Memory Access (NUMA) architectures. We present DR-BW, a new tool based on machine learning to identify bandwidth contention in NUMA architectures and provide optimization guidance. DR-BW collects performance data with …
Indoor Chemistry: Development Of An Indoor Surface Extractor, Hannah Rose Przelomski
Indoor Chemistry: Development Of An Indoor Surface Extractor, Hannah Rose Przelomski
Dissertations, Theses, and Masters Projects
People spend around 90% of their time indoors. This means that indoor air can have an impact on human health. One of the main factors that makes indoor air differ from outdoor air is indoor areas have a higher surface area to volume ratio than outdoor areas. Surfaces give aerosol particles a place to deposit where they can stick or react. Some of this material can leave the surface and reenter the air. Being able to analyze the material on different indoor surfaces will help further the understanding of indoor surfaces’ impact on indoor air. A surface extractor was developed …
Calculation Of Gluon Pdf In The Nucleon Using Pseudo-Pdf Formalism With Wilson Flow Technique In Lqcd, Md Tanjib Atique Khan
Calculation Of Gluon Pdf In The Nucleon Using Pseudo-Pdf Formalism With Wilson Flow Technique In Lqcd, Md Tanjib Atique Khan
Dissertations, Theses, and Masters Projects
A comprehensive study of the gluonic content in the nucleon from a first principles lattice quantum chromodynamics calculation is presented. The unpolarized gluonic distribution in the nucleon is calculated using the pseudo-PDF framework on the lattice. First, the spectral analyses of the low-lying states in the nucleon, as well as in the delta are performed on the lattice, identifying baryons states with hybrid characteristics, in which the gluons play a manifestly structural role, and determining a set of operators which have significant overlaps onto the ground state of the nucleon. Techniques such as distillation for smearing the quark fields, momentum …
Excited J-- Resonances In Meson-Meson Scattering From Lattice Qcd, Christopher Johnson
Excited J-- Resonances In Meson-Meson Scattering From Lattice Qcd, Christopher Johnson
Dissertations, Theses, and Masters Projects
Understanding the excited light meson spectrum is vital to our understanding of how quarks and gluons bind to become hadrons. This sector is home to a plethora of states including hadrons laying outside the quark model. Distinguishing the from the rest of the spectrum would be made easier if we first had a handle on the light quark anti-quark spectrum. I present the first determination of excited light JPC=1--,2--,3-- resonances in meson-meson scattering at the SU(3) flavor point from lattice QCD. This system can be described in the context of pseudoscalar-vector elastic scattering and I determine two 1-- resonances; a …
Endangered Species Act: Quantifying Threats Impacting Listing, Delaney Costante
Endangered Species Act: Quantifying Threats Impacting Listing, Delaney Costante
Dissertations, Theses, and Masters Projects
With species increasingly becoming imperiled due to anthropogenic activities, conservation practitioners are tasked with determining conservation priorities in order to make the best use of limited resources. The United States’ Endangered Species Act (ESA) has two listing statuses into which imperiled species are placed to receive protections: Threatened or Endangered. In the first chapter, our objective was to identify differences between Threatened and Endangered species beyond what is outlined in their ESA definitions. To our knowledge, this is the first study to compare listing status for species protected by the ESA on the basis of types and number of threats …
Quantifying The Increased Resiliency Of Chesapeake Bay Hypoxia To Environmental Conditions: A Benefit Of Nutrient Reductions, Luke Thomas Frankel
Quantifying The Increased Resiliency Of Chesapeake Bay Hypoxia To Environmental Conditions: A Benefit Of Nutrient Reductions, Luke Thomas Frankel
Dissertations, Theses, and Masters Projects
Seasonal hypoxia is a characteristic feature of the Chesapeake Bay as a result of anthropogenic eutrophication from agriculture and urban development throughout the watershed. Although in recent years coordinated management efforts have successfully reduced the flux of nutrients into the Bay, the overall goal of sufficient oxygen concentrations below the pycnocline for living resources remains unfulfilled. This was particularly apparent in 2018 and 2019 when the volume of hypoxic water exceeded the long-term (35-year) average due to anomalously high riverine discharge. To quantify the impact of watershed nutrient reductions, conventional statistical methods were employed in concert with a 3-D numerical …
On Supporting Android Software Developers And Testers, Carlos Eduardo Bernal Cardenas
On Supporting Android Software Developers And Testers, Carlos Eduardo Bernal Cardenas
Dissertations, Theses, and Masters Projects
Users entrust mobile applications (apps) to help them with different tasks in their daily lives. However, for each app that helps to finish a given task, there are a plethora of other apps in popular marketplaces that offer similar or nearly identical functionality. This makes for a competitive market where users will tend to favor the highest quality apps in most cases. Given that users can easily get frustrated by apps which repeatedly exhibit bugs, failures, and crashes, it is imperative that developers promptly fix problems both before and after the release. However, implementing and maintaining high quality apps is …
Sediment And Terrestrial Organic Carbon Budgets For The Offshore Ayeyarwady Delta: Establishing A Baseline For Future Change, Evan Rose Flynn
Sediment And Terrestrial Organic Carbon Budgets For The Offshore Ayeyarwady Delta: Establishing A Baseline For Future Change, Evan Rose Flynn
Dissertations, Theses, and Masters Projects
Large river deltas serve as globally important archives of terrestrial and shallow marine biogeochemical signatures because of rapid sediment burial, and have the potential to impact global biogeochemical cycling on modern and geologic timescales. This study investigates modern sediment and terrestrial organic carbon (TerrOC) accumulation within the offshore Ayeyarwady Delta in order to determine sediment and TerrOC budgets for this largely understudied mega-delta. The Ayeyarwady is the world’s third largest delta in terms of sediment supply, and remains one of the last long free-flowing rivers in Asia. However, recent increases in regional anthropogenic impacts risk severe alterations to sediment and …
Rethinking Cache Hierarchy And Interconnect Design For Next-Generation Gpus, Mohamed Assem Abd Elmohsen Ibrahim
Rethinking Cache Hierarchy And Interconnect Design For Next-Generation Gpus, Mohamed Assem Abd Elmohsen Ibrahim
Dissertations, Theses, and Masters Projects
To match the increasing computational demands of GPGPU applications and to improve peak compute throughput, the core counts in GPUs have been increasing with every generation. However, the famous memory wall is a major performance determinant in GPUs. In other words, in most cases, peak throughput in GPUs is ultimately dictated by memory bandwidth. Therefore, to serve the memory demands of thousands of concurrently executing threads, GPUs are equipped with several sources of bandwidth such as on-chip private/shared caching resources and off-chip high bandwidth memories. However, the existing sources of bandwidth are often not sufficient for achieving optimal GPU performance. …
Radiofrequency Ac Zeeman Trapping For Neutral Atoms, Andrew Peter Rotunno
Radiofrequency Ac Zeeman Trapping For Neutral Atoms, Andrew Peter Rotunno
Dissertations, Theses, and Masters Projects
This thesis presents the first experimental demonstration of a two-wire AC Zeeman trap on an atom chip. The AC Zeeman energy is a resonant, bipolar, state-dependent atomic energy shift produced by alternating magnetic fields with frequencies near hyperfine transitions. We demonstrate that high gradients in this energy, as near an atom chip, can produce a spin-state selective force greater than gravity for ultracold rubidium atoms. Our novel trap is generated by a local minimum in AC Zeeman energy. Using less than one watt of power, we demonstrate trap frequency on the order of a few hundred Hz, trap depth about …
Distributed Byzantine Tolerant Machine Learning, Qi Xia
Distributed Byzantine Tolerant Machine Learning, Qi Xia
Dissertations, Theses, and Masters Projects
Oftentimes, training a large-scale deep learning neural network on a single machine becomes more difficult in a complex network model. Distributed training provides an efficient solution, but opens up participating workers to Byzantine attacks. This problem emerges when some workers cheat during uploading gradients or weights to the central server, e.g., the information received by the server is not always the true result computed by workers. In order to address this problem, we investigate Byzantine problems in distributed machine learning and respectively defend against these kinds of attacks in three scenarios: i) classic distributed machine learning; ii) federated learning; and …
Evaluating The Use Of Acoustic Warning Signals To Reduce Avian Collision Risk, Robin Grace Thady
Evaluating The Use Of Acoustic Warning Signals To Reduce Avian Collision Risk, Robin Grace Thady
Dissertations, Theses, and Masters Projects
Collisions with human-made structures are responsible for billions of bird deaths each year, resulting in ecological damage as well as regulatory and financial burdens to many industries. Acoustic warning signals can alert birds to obstacles in their flight paths in order to mitigate collisions, but these signals should be tailored to the sensory ecology of birds in flight. The effectiveness of various acoustic warning signals likely depends on the influence of background noise and the relative ability of various sound types to propagate within a landscape. I evaluated the ability of four sound signals to elicit collision-avoidant flight behaviors from …
Controls On Estuarine Sediment Bed Erodibility: Insights From The York River Estuary, Cristin Lee Wright
Controls On Estuarine Sediment Bed Erodibility: Insights From The York River Estuary, Cristin Lee Wright
Dissertations, Theses, and Masters Projects
The erodibility of estuarine sediment beds has a number of ecological and societal implications, including alteration of benthic habitats, light-limitation of primary production, and reintroduction of pollutants to the water column, as well as impacts on dredging operations and on the fate of potentially dangerous objects on the seafloor. The objectives of this study are to better understand controls on bed erodibility in estuarine environments, including the roles of sediment grain size, water content, percent organics, and bed fabric, as well as effects of tides, storms, salinity distribution, river discharge, and location within the estuary. An extensive set of erosion …
Light-Matter Interactions In Quasi-Two-Dimensional Geometries, David James Lahneman
Light-Matter Interactions In Quasi-Two-Dimensional Geometries, David James Lahneman
Dissertations, Theses, and Masters Projects
Emergent phenomena that occur at length scales smaller than approximately half the wavelength of light cannot be resolved by conventional optical techniques due to the Abbe diffraction limit. Scattering-type scanning near-field infrared microscopy (S-SNIM) can circumvent this diffraction limit allowing infrared spectroscopy at nano-scale dimensions independent of the wavelength. Additionally, there is enhanced surface sensitivity resulting from this nanoconfinement of infrared light. S-SNIM is uniquely suitable to study a diverse range of material properties inaccessible by far-field optics in the infrared such as the optical properties of ultrathin films as well as hybrid light matter surface waves called polaritons. Initially, …
Electronic Effects In A Cyclization Cascade To Diversified, Polycyclic, Helical Molecules, Caleb Lee Burns
Electronic Effects In A Cyclization Cascade To Diversified, Polycyclic, Helical Molecules, Caleb Lee Burns
Dissertations, Theses, and Masters Projects
Heterocyclic aromatic compounds and their derivatives are ubiquitous in the pharmaceutical and photochemical industries. Naphthochromene derivatives in particular have garnered great interest for their photochemical properties and biological activity. Herein, the effects of electronics on a three-step cascade reaction between aryl substituted 2-(4-aryl-3-((triethylsilyl)oxy)but-1-yn-1-yl)phenols and structurally diverse aldehydes is explored. The cascade is initiated by alkynyl substrate addition to BF3-activated aldehydes. The aldehyde undergoes condensation with the substrate phenol moiety forming an oxocarbenium ion, this initiates the alkynyl-Prins cyclization forming a new six-membered heterocyclic ring with an internal alkenyl cation. The cation is subsequently trapped by a Friedel-Crafts (FC) reaction by …
Forward & Off-Forward Parton Distributions From Lattice Qcd, Colin Paul Egerer
Forward & Off-Forward Parton Distributions From Lattice Qcd, Colin Paul Egerer
Dissertations, Theses, and Masters Projects
The interpretation of (semi-)inclusive and certain exclusive scattering processes relies on the factorization of hard parton level cross sections from long-range and non-perturbative parton correlations. The familiar Parton Distribution Functions (PDFs) and Generalized Parton Distributions quantify the non-perturbative dynamics in these situations and address a number of key questions surrounding the structure of hadrons. A certain class of matrix elements accessible in lattice QCD, so called Lattice Cross Sections, have been shown to factorize into these collinear distributions in a manner akin to the factorization of hadronic cross sections. In the short-distance regime, matrix elements of space-like separated two-current operators …
Dealing With Many Species: Improving Methodology For Forming And Assessing Species Complexes, Kristen Omori
Dealing With Many Species: Improving Methodology For Forming And Assessing Species Complexes, Kristen Omori
Dissertations, Theses, and Masters Projects
In the United States, the Magnuson-Stevens Reauthorization Act mandates that all federally fished species must have catch limits, which can be challenging for data-limited species. One approach is to assess and manage a group of species with similar life history characteristics, vulnerability to the fishery, and overlapping geographic distributions in a single management unit, or a complex (i.e., stock or species complex). Using the Gulf of Alaska (GOA) Other Rockfish complex as a case study, the main goals of this dissertation are five-fold: 1) review species complexes in the United States; 2) compare multivariate techniques for assigning species to complexes; …
Investigating The Electron Transfer Dynamics Of Eosin Y Photosensitizers Using Single Molecule Spectroscopy, Kelly Margaret Kopera
Investigating The Electron Transfer Dynamics Of Eosin Y Photosensitizers Using Single Molecule Spectroscopy, Kelly Margaret Kopera
Dissertations, Theses, and Masters Projects
Growing global energy demands have necessitated the search for alternative sources of renewable fuels. Dye-sensitized photocatalysis (DSP) is a promising low cost, sustainable method that directly converts solar energy to readily usable forms of energy such as hydrogen fuel. While DSP is a promising technology, its efficiency is limited by back electron transfer and kinetic redundancy. In order to fully understand these processes, single-molecule spectroscopy (SMS) is used to probe the electron transfer (ET) dynamics of photosensitizers. In particular, eosin Y (EY), a brominated fluorescein derivative that undergoes intersystem crossing prior to injection, is investigated using SMS. In this approach, …
Dihadron Beam Spin Asymmetries On An Unpolarized Hydrogen Target With Clas12, Timothy Barton Hayward
Dihadron Beam Spin Asymmetries On An Unpolarized Hydrogen Target With Clas12, Timothy Barton Hayward
Dissertations, Theses, and Masters Projects
The semi-inclusive deep inelastic scattering process, where an electron scatters off a proton target at high enough energy that the process can be described by the scattering off a single constituent particle, offers targeted access to the internal structure of the nucleon. The process can be described in two phases by parton distribution functions (PDFs), which describe the likelihood of finding a quark or gluon in a particular state inside of the nucleon and then by fragmentation functions (FFs) which describe the likelihood of forming a particular final state particle. One way to study these properties is via the measurement …
Ac & Dc Zeeman Interferometric Sensing With Ultracold Trapped Atoms On A Chip, Shuangli Du
Ac & Dc Zeeman Interferometric Sensing With Ultracold Trapped Atoms On A Chip, Shuangli Du
Dissertations, Theses, and Masters Projects
This thesis presents progress in developing a trapped atom interferometer on a chip, based on AC Zeeman potentials. An atom interferometer is a high-precision measuring tool that can detect various types of forces and potentials. The trapped atom interferometer introduced in this thesis targets the shortcomings of traditional ballistic atom interferometers, which are typically meter-scale in height. Notably, a trapped atom interferometer has a localized atomic sample, a potentially longer interferometric phase accumulation time, and the prospect of being the basis for a more compact instrument. This thesis presents multiple projects in the development of a trapped atom interferometer based …
Improving Observation, Assessment, And Management Of Atlantic Coastal Sharks, Cassidy Dawn Peterson
Improving Observation, Assessment, And Management Of Atlantic Coastal Sharks, Cassidy Dawn Peterson
Dissertations, Theses, and Masters Projects
Coastal sharks represent a group of stocks for which observation, assessment, and management are particularly challenging. Large distributional ranges, complex migratory behavior, low economic value, and relatively few observations in fishery independent surveys hinder relative abundance estimation. Assessing stock status of coastal sharks is encumbered by limited data availability, data quality, and knowledge of life history strategy. Further, coastal sharks are challenging to manage due to their slow intrinsic population growth rates, competing stakeholder interests, history of overexploitation, and in some cases, subjection to international exploitation. This dissertation aimed to improve the capacity to observe relative abundance of coastal sharks. …
Mass Spectrometry-Based Proteomics: An Experimental Study Of Differential Bacteriophage Protein Expression And A Computational Investigation Of The Effects Of Proton Affinity On The Fragmentation Of Proline-Containing Dipeptides, Hao Qian
Dissertations, Theses, and Masters Projects
After decades with the development of genetics study, the next step of molecular biology had already been moved onto proteomics. The proteomics study provides an innovative aspect to deduct the relationship between genes and proteins. Meanwhile, research that focuses on the mechanism of protein interactions and intrinsic properties of proteins never cease. The mass spectrometry-based proteomics approaches have already shown their versatile and superior in studying the whole proteome of complicated organisms. This study focuses on practicing bottom-up method in determining and characterizing the expressed proteome of two mycobacteriophages, CrimD and Larva. The expressed proteins of CrimD and Larva in …
Revisiting Isolation For System Security And Efficiency In The Era Of Internet Of Things, Lele Ma
Revisiting Isolation For System Security And Efficiency In The Era Of Internet Of Things, Lele Ma
Dissertations, Theses, and Masters Projects
Isolation is a fundamental paradigm for secure and efficient resource sharing on a computer system. However, isolation mechanisms in traditional cloud computing platforms are heavy-weight or just not feasible to be applied onto the computing environment for Internet of Things(IoT). Most IoT devices have limited resources and their servers are less powerful than cloud servers but are widely distributed over the edge of the Internet. Revisions to the traditional isolation mechanisms are needed in order to improve the system security and efficiency in these computing environments. The first project explores container-based isolation for the emerging edge computing platforms. We show …
High-Dimensional Machine Learning Models In Fintech, Qiong Wu
High-Dimensional Machine Learning Models In Fintech, Qiong Wu
Dissertations, Theses, and Masters Projects
This thesis develops several forecasting models for simultaneously predicting the prices of d assets traded in financial markets, a most fundamental problem in the emerging area of ``FinTech''. The models are optimized to address three critical challenges, C1. High-dimensional interactions between assets. Assets could interact (e.g., Amazon's disclosure of its revenue change in cloud services could indicate that revenues also could change in other cloud providers). The number of possible interactions is quadratic in d, and is often much larger than the number of observations. C2. Non-linearity of the hypothesis class. Linear models are usually insufficient to characterize the relationship …
Uncovering Information Operations On Twitter Using Natural Language Processing And The Dynamic Wavelet Fingerprint, Spencer Lee Kirn
Uncovering Information Operations On Twitter Using Natural Language Processing And The Dynamic Wavelet Fingerprint, Spencer Lee Kirn
Dissertations, Theses, and Masters Projects
Information Operations (IO) are campaigns waged by covert, powerful entities to distort public discourse in a direction that is advantageous for them. It is the behaviors of the underlying networks that signal these campaigns in action, not the specific content they are posting. In this dissertation we introduce a social media analysis system that uncovers these behaviors by analyzing the specific post timings of underlying accounts and networks. The presented method first clusters tweets based on content using Natural Language Processing (NLP). Each of these clusters - referred to as topics - are plotted in time using the attached metadata …