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University of Louisville

Electronic Theses and Dissertations

2016

Articles 1 - 22 of 22

Full-Text Articles in Physical Sciences and Mathematics

Spreading Speeds Along Shifting Resource Gradients In Reaction-Diffusion Models And Lattice Differential Equations., Jin Shang Dec 2016

Spreading Speeds Along Shifting Resource Gradients In Reaction-Diffusion Models And Lattice Differential Equations., Jin Shang

Electronic Theses and Dissertations

A reaction-diffusion model and a lattice differential equation are introduced to describe the persistence and spread of a species along a shifting habitat gradient. The species is assumed to grow everywhere in space and its growth rate is assumed to be monotone and positive along the habitat region. We show that the persistence and spreading dynamics of a species are dependent on the speed of the shifting edge of the favorable habitat, c, as well as c*(∞) and c*(−∞), which are formulated in terms of the dispersal kernel and species growth rates in both directions. When …

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A Reduced Labeled Samples (Rls) Framework For Classification Of Imbalanced Concept-Drifting Streaming Data., Elaheh Arabmakki Dec 2016

A Reduced Labeled Samples (Rls) Framework For Classification Of Imbalanced Concept-Drifting Streaming Data., Elaheh Arabmakki

Electronic Theses and Dissertations

Stream processing frameworks are designed to process the streaming data that arrives in time. An example of such data is stream of emails that a user receives every day. Most of the real world data streams are also imbalanced as is in the stream of emails, which contains few spam emails compared to a lot of legitimate emails. The classification of the imbalanced data stream is challenging due to the several reasons: First of all, data streams are huge and they can not be stored in the memory for one time processing. Second, if the data is imbalanced, the accuracy …

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Multipurpose Tenofovir Disoproxil Fumarate Electrospun Fibers For The Prevention Of Hiv-1 And Hsv-2 Infections., Kevin Tyo Aug 2016

Multipurpose Tenofovir Disoproxil Fumarate Electrospun Fibers For The Prevention Of Hiv-1 And Hsv-2 Infections., Kevin Tyo

Electronic Theses and Dissertations

Sexually transmitted infections affect hundreds of millions of worldwide. Both human immunodeficiency virus (HIV-1 and -2) and herpes simplex virus-2 (HSV-2) remain incurable, urging the development of new prevention strategies. While current prophylactic technologies are dependent on strict user adherence to achieve efficacy, there is a dearth of delivery vehicles that provide discreet and convenient administration, combined with prolonged-delivery of active agents. To address these needs, we created electrospun fibers (EFs) comprised of FDA-approved polymers, poly(lactic-co-glycolic acid) (PLGA) and poly(DL-lactide-co-ε-caprolactone) (PLCL), to provide sustained-release and in vitro protection against HIV-1 and HSV-2. PLGA and PLCL EFs, incorporating the antiretroviral, tenofovir …

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A Study Of The Radiative Pion Capture Process As A Background To The Search For Muon To Electron Conversion With The Mu2e Experiment., Jacob Colston Aug 2016

A Study Of The Radiative Pion Capture Process As A Background To The Search For Muon To Electron Conversion With The Mu2e Experiment., Jacob Colston

Electronic Theses and Dissertations

This thesis will introduce radiative pion capture (RPC), a process which can produce a fake signal in a search for the coherent conversion of a muon to an electron in the presence of a nucleus. There will be a brief introduction to standard model (SM) physics, as well as some more in-depth discussion of the relevant high energy physics at the Mu2e experiment. We will discuss charged lepton flavor violation (CLFV), as well as Supersymmetry, which predicts CLFV at higher intensities than the SM prediction. A description of the RPC process follows, including the external and internal conversions in pion …

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Materials Design And Band Gap Engineering Of Complex Nanostructures Using A Semi-Empirical Approach : Low Dimensional Boron Nanostructures, H-Bn Sheet With Graphene Domains And Holey Graphene., Cherno Baba Kah Aug 2016

Materials Design And Band Gap Engineering Of Complex Nanostructures Using A Semi-Empirical Approach : Low Dimensional Boron Nanostructures, H-Bn Sheet With Graphene Domains And Holey Graphene., Cherno Baba Kah

Electronic Theses and Dissertations

This dissertation will explore the potential of a semi-empirical Hamiltonian, developed by the research group at the University of Louisville, in predicting the existence of new families of low-dimensional boron nanostructures based on icosahedral α-B12 clusters, and in tuning the band gaps of h-BN sheets with graphene domains and holey graphene. This semi-empirical Hamiltonian models electron-electron and electron-ion interactions using environment-dependent (ED) functions, and ion-ion interactions via usual pairwise terms. Additional features of our approach are that it uses a linear combination of atomic orbitals (LCAO) framework to describe the Hamiltonian and it calculates the charge distribution around a …

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Mathematical Hybrid Models For Image Segmentation., Carlos M. Paniagua Mejia Aug 2016

Mathematical Hybrid Models For Image Segmentation., Carlos M. Paniagua Mejia

Electronic Theses and Dissertations

Two hybrid image segmentation models that are able to process a wide variety of images are proposed. The models take advantage of global (region) and local (edge) data of the image to be segmented. The first one is a region-based PDE model that incorporates a combination of global and local statistics. The influence of each statistic is controlled using weights obtained via an asymptotically stable exponential function. Through incorporation of edge information, the second model extends the capabilities of a strictly region-based variational formulation, making it able to process more general images. Several examples are provided showing the improvements of …

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Propensity Score Based Methods For Estimating The Treatment Effects Based On Observational Studies., Younathan Abdia Aug 2016

Propensity Score Based Methods For Estimating The Treatment Effects Based On Observational Studies., Younathan Abdia

Electronic Theses and Dissertations

This dissertation consists of two interconnected research projects. The first project was a study of propensity scores based statistical methods for estimating the average treatment effect (ATE) and the average treatment effect among treated (ATT) when there are two treatment groups. The ATE is defined as the mean of the individual causal effects in the whole population, while ATT is defined as the treatment effect for the treated population. Propensity score based statistical methods, such as matching, regression, stratification, inverse probability weighting (IPW), and doubly robust (DR) methods were used to estimate the ATE and ATT. Simulation studies and case …

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Analyzing The Phenologic Dynamics Of Kudzu (Pueraria Montana) Infestations Using Remote Sensing And The Normalized Difference Vegetation Index., Faye Peters May 2016

Analyzing The Phenologic Dynamics Of Kudzu (Pueraria Montana) Infestations Using Remote Sensing And The Normalized Difference Vegetation Index., Faye Peters

Electronic Theses and Dissertations

Non-native invasive species are one of the major threats to worldwide ecosystems. Kudzu (Pueraria montana) is a fast-growing vine native to Asia that has invaded regions in the United States making management of this species an important issue. Estimated normalized difference vegetation index (NDVI) values for the years 2000 to 2015 were calculated using data collected by Landsat and MODIS platforms for three infestation sites in Kentucky. The STARFM image-fusing algorithm was used to combine Landsat- and MODIS-derived NDVI into time series with a 30 m spatial resolution and 16 day temporal resolution. The fused time series was …

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Chemoselective Reactions And Their Applications In Metabolite Isolation And Analysis., Sadakatali Shokatali Gori May 2016

Chemoselective Reactions And Their Applications In Metabolite Isolation And Analysis., Sadakatali Shokatali Gori

Electronic Theses and Dissertations

Chemoselectivity is the preferential reaction of a reagent with a select functional group among other plausible reactions. This dissertation describes chemoselective reagents and methods explored to develop more accurate, efficient and high-throughput means to quantify metabolites containing either thiol, carboxylic acid or 1,2-diol moieties directly from biological mixtures. Chapter 1 discusses how dysregulation of thiol- or carboxylic acid-containing metabolites is either the cause or effect of cellular dysfunction. Quantifying such metabolites is important in discovery of pathways to understand etiology of diseases. Chapter 1 also discusses the need for sustainable syntheses using renewable resources and describes the traditional methods for …

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Urban Flooding And Sewer Inundation On The University Of Louisville Belknap Campus., Justin T. Hall May 2016

Urban Flooding And Sewer Inundation On The University Of Louisville Belknap Campus., Justin T. Hall

Electronic Theses and Dissertations

Over the past few decades on the University of Louisville Belknap campus urban flooding has become more frequent as a result of surface water runoff and sewer inundation. This urban flooding is a result of ongoing watershed urbanization and rapid expansion of the local sewer system to accommodate the expanding city of Louisville. However little research has been conducted on this issue, despite continued flooding on and adjacent to campus. Using the EPA Storm Water Management Model (SWMM) we applied a dual drainage modeling approach that combines both surface and subsurface drainage data to produce a flood hydrograph at the …

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Development And Applications Of Novel Hf-Based Fluorination Reagents : Dmpu-Hf., Otome Elisha Okoromoba May 2016

Development And Applications Of Novel Hf-Based Fluorination Reagents : Dmpu-Hf., Otome Elisha Okoromoba

Electronic Theses and Dissertations

The utility of fluorine in medicinal and manufacturing chemistry is undisputed. Despite its usefulness, the incorporation of fluorine in organic molecules is not without challenges. Regardless of their electrophilic or nucleophilic nature, most, if not all, fluorinating reagents derive from HF. Nucleophilic reagents are less expensive compared with their counterparts, and many are not commercially available. The Hammond laboratory is interested in developing and applying HF-based fluorination reagents that are cost effective and capable of enhancing both classical and metal based transformations. The following chapters describe some of the applications of our HF-based reagent. Chapter 2 discusses the preparation and …

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A Log Rank Test For Clustered Data Under Informative Within-Cluster Group Size., Mary Elizabeth Gregg May 2016

A Log Rank Test For Clustered Data Under Informative Within-Cluster Group Size., Mary Elizabeth Gregg

Electronic Theses and Dissertations

The log rank test is a popular nonparametric test for comparing the marginal survival distribution of two groups. When data are organized within clusters and the size of clusters or the distribution of group membership within a cluster is related to an outcome of interest, traditional methods of data analysis can be biased. In this thesis, we develop a within-cluster group weighted log rank test to compare marginal survival time distributions between groups from clustered data, correcting for cluster size and intra-cluster group size informativeness. The performance of this new test is compared with the unweighted and cluster-weighted log rank …

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Integrated Analysis Of Mirna/Mrna Expression And Gene Methylation Using Sparse Canonical Correlation Analysis., Dake Yang May 2016

Integrated Analysis Of Mirna/Mrna Expression And Gene Methylation Using Sparse Canonical Correlation Analysis., Dake Yang

Electronic Theses and Dissertations

MicroRNAs (miRNAs) are a large number of small endogenous non-coding RNA molecules (18-25 nucleotides in length) which regulate expression of genes post-transcriptionally. While a variety of algorithms exist for determining the targets of miRNAs, they are generally based on sequence information and frequently produce lists consisting of thousands of genes. Canonical correlation analysis (CCA) is a multivariate statistical method that can be used to find linear relationships between two data sets, and here we apply CCA to find the linear combination of differentially expressed miRNAs and their corresponding target genes having maximal negative correlation. Due to the high dimensionality, sparse …

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Investigating The Influences Of Climate On The High Elevation Snowpack Hydrology In The Upper Colorado Region., Claire-Louise Bode May 2016

Investigating The Influences Of Climate On The High Elevation Snowpack Hydrology In The Upper Colorado Region., Claire-Louise Bode

Electronic Theses and Dissertations

A change in climate in the western United States has already affected and will continue to affect the onset of snow melt in many parts of the country. The effect of climate change on snow water equivalent, snowmelt runoff and total streamflow with respect to their elevation distribution is examined across the Colorado Headwaters Basin. This is a high altitude location within the Upper Colorado Basin region. The total streamflow of this region has a significant contribution from the spring season snow melt. An increase in air temperature in the Colorado Headwaters Basin over a few years will change the …

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Some Contributions To Nonparametric And Semiparametric Inference For Clustered And Multistate Data., Sandipan Dutta May 2016

Some Contributions To Nonparametric And Semiparametric Inference For Clustered And Multistate Data., Sandipan Dutta

Electronic Theses and Dissertations

This dissertation is composed of research projects that involve methods which can be broadly classified as either nonparametric or semiparametric. Chapter 1 provides an introduction of the problems addressed in these projects, a brief review of the related works that have done so far, and an outline of the methods developed in this dissertation. Chapter 2 describes in details the first project which aims at developing a rank-sum test for clustered data where an outcome from group in a cluster is associated with the number of observations belonging to that group in that cluster. Chapter 3 proposes the use of …

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Sparse Feature Learning For Image Analysis In Segmentation, Classification, And Disease Diagnosis., Ehsan Hosseini-Asl May 2016

Sparse Feature Learning For Image Analysis In Segmentation, Classification, And Disease Diagnosis., Ehsan Hosseini-Asl

Electronic Theses and Dissertations

The success of machine learning algorithms generally depends on intermediate data representation, called features that disentangle the hidden factors of variation in data. Moreover, machine learning models are required to be generalized, in order to reduce the specificity or bias toward the training dataset. Unsupervised feature learning is useful in taking advantage of large amount of unlabeled data, which is available to capture these variations. However, learned features are required to capture variational patterns in data space. In this dissertation, unsupervised feature learning with sparsity is investigated for sparse and local feature extraction with application to lung segmentation, interpretable deep …

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Propensity Score Methods : A Simulation And Case Study Involving Breast Cancer Patients., John Craycroft May 2016

Propensity Score Methods : A Simulation And Case Study Involving Breast Cancer Patients., John Craycroft

Electronic Theses and Dissertations

Observational data presents unique challenges for analysis that are not encountered with experimental data resulting from carefully designed randomized controlled trials. Selection bias and unbalanced treatment assignments can obscure estimations of treatment effects, making the process of causal inference from observational data highly problematic. In 1983, Paul Rosenbaum and Donald Rubin formalized an approach for analyzing observational data that adjusts treatment effect estimates for the set of non-treatment variables that are measured at baseline. The propensity score is the conditional probability of assignment to a treatment group given the covariates. Using this score, one may balance the covariates across treatment …

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Direct Band Gap Gallium Antimonide Phosphide (Gasbxp1-X) For Solar Fuels., Harry Benjamin Russell May 2016

Direct Band Gap Gallium Antimonide Phosphide (Gasbxp1-X) For Solar Fuels., Harry Benjamin Russell

Electronic Theses and Dissertations

Photoelectrochemical water splitting has been identified as a promising route for achieving sustainable energy future. However, semiconductor materials with the appropriate optical, electrical and electrochemical properties have yet to be discovered. In search of an appropriate semiconductor to fill this gap, GaSbP, a semiconductor never tested for PEC performance is proposed here and investigated. Density functional theory (DFT+U) techniques were utilized to predict band gap and band edge energetics for GaSbP alloys with low amount of antimony. The overall objective of this dissertation is to understand the suitability of GaSbxP1-x alloys for photoelectrochemical water splitting application. Specifically, …

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Computation Of Least Angle Regression Coefficient Profiles And Lasso Estimates., Sandamala Hettigoda May 2016

Computation Of Least Angle Regression Coefficient Profiles And Lasso Estimates., Sandamala Hettigoda

Electronic Theses and Dissertations

Variable selection plays a significant role in statistics. There are many variable selection methods. Forward stagewise regression takes a different approach among those. In this thesis Least Angle Regression (LAR) is discussed in detail. This approach has similar principles as forward stagewise regression but does not suffer from its computational difficulties. By using a small artificial data set and the well-known Longley data set, the LAR algorithm is illustrated in detail and the coefficient profiles are obtained. Furthermore a penalized approach to variable reduction called the LASSO is discussed, and it is shown how to compute its coefficient profiles efficiently …

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Synthesis, Characterization, And Electronic Properties Of Novel 2d Materials : Transition Metal Dichalcogenides And Phosphorene., George Anderson May 2016

Synthesis, Characterization, And Electronic Properties Of Novel 2d Materials : Transition Metal Dichalcogenides And Phosphorene., George Anderson

Electronic Theses and Dissertations

Scaling electronic devices has become paramount. The current work builds upon scaling efforts by developing novel synthesis methods and next generation sensing devices based on 2D materials. A new combination method utilizing thermal evaporation and chemical vapor deposition was developed and analyzed to show the possibilities of Transition Metal Dichalcogenide monolayers and heterostructures. The materials produced from the above process showed high degrees of compositional control in both spatial dimensions and chemical structure. Characterization shows controlled fabrication of heterostructures, which may pave the way for future band gap engineering possibilities. In addition, Phosphorene based field effect transistors, photodetectors, and gas …

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Semi-Parametric Methods For Personalized Treatment Selection And Multi-State Models., Chathura K. Siriwardhana May 2016

Semi-Parametric Methods For Personalized Treatment Selection And Multi-State Models., Chathura K. Siriwardhana

Electronic Theses and Dissertations

This dissertation contains three research projects on personalized medicine and a project on multi-state modelling. The idea behind personalized medicine is selecting the best treatment that maximizes interested clinical outcomes of an individual based on his or her genetic and genomic information. We propose a method for treatment assignment based on individual covariate information for a patient. Our method covers more than two treatments and it can be applied with a broad set of models and it has very desirable large sample properties. An empirical study using simulations and a real data analysis show the applicability of the proposed procedure. …

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Inference For A Zero-Inflated Conway-Maxwell-Poisson Regression For Clustered Count Data., Hyoyoung Choo-Wosoba May 2016

Inference For A Zero-Inflated Conway-Maxwell-Poisson Regression For Clustered Count Data., Hyoyoung Choo-Wosoba

Electronic Theses and Dissertations

This dissertation is directed toward developing a statistical methodology with applications of the Conway-Maxwell-Poisson (CMP) distribution (Conway, R. W., and Maxwell, W. L., 1962) to count data. The count data for this dissertation exhibit three different characteristics: clustering, zero inflation, and dispersion. Clustering suggests that observations within clusters are correlated, and the zero inflation phenomenon occurs when the data exhibit excessive zero counts. Dispersion implies that the mean is greater/smaller than the variance unlike a Poisson distribution. The dissertation starts with an introduction of inference for a zero-inflated clustered count data in the first chapter. Then, it presents novel methodologies …

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