Physical Sciences and Mathematics Commons^™

Methods For Two-Sample Comparisons From Censored Time-To-Event Data, Nubyra Ahmed

Dissertations

In the analysis of censored survival data, it is frequently of interest to determine the efficacy of a treatment or new method over a control or existing method. For this purpose, one may report estimates of the two survival functions or, more specifically, their difference, accompanied by simultaneous confidence bands (SCBs). Alternatively, or in addition, one may conduct hypothesis testing for the difference of the two survival functions.

The first project exploits two bootstrap methods to develop new Wald-type SCBs for the difference of survival functions. The censored data bootstrap is employed to obtain nonparametric SCBs for the difference of …

Data Mining In Computational Proteomics And Genomics, Yang Song

Dissertations

This dissertation addresses data mining in bioinformatics by investigating two important problems, namely peak detection and structure matching. Peak detection is useful for biological pattern discovery while structure matching finds many applications in clustering and classification.

The first part of this dissertation focuses on elastic peak detection in 2D liquid chromatographic mass spectrometry (LC-MS) data used in proteomics research. These data can be modeled as a time series, in which the X-axis represents time points and the Y-axis represents intensity values. A peak occurs in a set of 2D LC-MS data when the sum of the intensity values in a …

Multiple Testing Procedures For Complex Structured Hypotheses And Directional Decisions, Anjana Grandhi

Dissertations

Several multiple testing procedures are developed based on the inherent structure of the tested hypotheses and specific needs of data analysis. Incorporating the inherent structure of the hypotheses results in development of more powerful and situation-specific multiple testing procedures than existing ones. The focus of this dissertation is on developing multiple testing procedures that utilize the information on this structure of the hypotheses and aims at answering research questions while controlling appropriate error rates.

In the first part of the thesis, a mixed directional false discovery rate (mdFDR) controlling procedure is developed in the context of uterine fibroid gene expression …

Designing Novel Abstraction Networks For Ontology Summarization And Quality Assurance, Christopher Ochs

Dissertations

Biomedical ontologies are complex knowledge representation systems. Biomedical ontologies support interdisciplinary research, interoperability of medical systems, and Electronic Healthcare Record (EHR) encoding. Ontologies represent knowledge using concepts (entities) linked by relationships. Ontologies may contain hundreds of thousands of concepts and millions of relationships. For users, the size and complexity of ontologies make it difficult to comprehend “the big picture” of an ontology's content. For ontology editors, size and complexity make it difficult to uncover errors and inconsistencies. Errors in an ontology will ultimately affect applications that utilize the ontology.

In prior studies abstraction networks (AbNs) were developed to provide a …

Information Filtering By Multiple Examples, Mingzhu Zhu

Dissertations

A key to successfully satisfy an information need lies in how users express it using keywords as queries. However, for many users, expressing their information needs using keywords is difficult, especially when the information need is complex. Search By Multiple Examples (SBME), a promising method for overcoming this problem, allows users to specify their information needs as a set of relevant documents rather than as a set of keywords.

Most of the studies on SBME adopt the Positive Unlabeled learning (PU learning) techniques by treating the user's provided examples (denoted as query examples) as positive set and the entire data …

Assessing Learning Outcomes And Social Capital Formation Resulting From The Use And Sharing Of Internet Knowledge Resources, Regina S. Collins

Dissertations

Today’s “digital natives” use the Internet to address most, if not all, their learning-related knowledge needs. This research evaluates the outcomes of formal learning activities requiring students to use, manage, share, and consolidate Internet knowledge resources (such as websites, videos, and blogs) to achieve both individual and group learning. This research takes an integrative approach to learning, capturing learner cognitive, interpersonal, and intrapersonal characteristics as well as the impact of the digital environment by evaluating the technological affordances of two different systems supporting such learning activities. This research also examines pedagogical modifications that would best integrate course assignments utilizing Internet …

Development Of Flexible Batteries Using Nano-Carbons And Polymers, Zhiqian Wang

Dissertations

Flexible electronics such as wearable equipment, displays, cell phones and smart cards require flexible power sources like batteries. In this thesis, the development of flexible batteries and supercapacitors are presented. Different types of flexible batteries including zinc carbon batteries, primary alkaline batteries, secondary alkaline batteries and zinc air cells are presented, These were designed, fabricated and improved using polymers and nano-carbons like carbon nanotubes (CNTs). CNTs are found to be effective as conductive additives compared to the traditional graphite. Purification is important to remove impurities that lead to side reactions/ corrosions. However, further treatment like carboxylation lead to higher electric …

Gal: A Stepwise Model For Automated Cloud Shadow Detection In Hico Oceanic Imagery Utilizing Guided Filter, Pixel Assignment, And Geometric Linking, Jennerpher Renee Meyers

Dissertations

Detection of cloud shadow pixels is an important step in image processing in several remote sensing ocean-color application domains, such as obtaining chlorophyll content. While shadow detection algorithms do exist, the vast majority are for over land which leaves few options for detection over water.

The detection of cloud shadow over water in HICO imagery is a unique problem. As its name implies, HICO (Hyperspectral Imager for the Coastal Ocean) imagery is produced for coastal and oceanic regions. Since land based algorithms remove water before processing, these approaches would not be applicable. The only currently published HICO shadow pixel detection …

Comparing Slug Test Methods For Unconfined Aquifers, Hussain Jaber Alfaifi

Dissertations

Slug test methods are used to determine in situ aquifer hydraulic conductivity (K) more quickly and economically than a pump test can. This study compares slug test methods for unconfined aquifers, looking at how to conduct a test using a physical slug, and at different analysis methods including Bouwer and Rice (1976), Kansas Geological Survey (KGS 1994), Hvorslev (1951) and Dagan (1978). Questions that motivated this study include: How well does the Bouwer and Rice method work? What is the most effective way to conduct a slug test? Does using a large physical slug relative to the well diameter and …

Failing To Replicate: Hypothesis Testing As A Crucial Key To Make Direct Replications More Credible And Predictable, Pedro Fernando Mateu Bullón

Dissertations

Theory cannot be fully validated unless the original results have been replicated, resulting in conclusion consistency. Replications are the strongest source to verify research findings and knowledge claims. Sciences such as medicine, chemistry, physics, genetics, and biology, are considered successful because their knowledge claims are buttressed by a large set of replications of original studies. Unfortunately in the social sciences many attempts to replicate fail and thus there is a continuing need for replication studies to confirm facts, expand knowledge to gain new understanding, and verify hypotheses. Two plausible explanations for the failure to replicate in the social sciences could …

Spatial, Temporal And Demographical Analysis Of Gulf Of Mexico Research Priorities, The Effect Of The Deepwater Horizon Oil Spill, Stephen Hiller Sempier

Dissertations

A set of twenty equally-weighted national ocean research priorities were define in 2007, but it was not clear if these priorities applied for the Gulf of Mexico. A series of three longitudinal surveys of people who conduct research, sponsor research or use research for professional or recreational purposes was released that focused on the twenty research priorities and asked people how they rated each. A convenience sampling method was employed, which suggests that the results are constrained to the survey respondents and should not be extrapolated to a larger population. More than 1,500 people completed the 2013 GMRP survey and …

Secure And Reliable Routing Protocol For Transmission Data In Wireless Sensor Mesh Networks, Nooh Adel Bany Muhammad

Dissertations

Abstract

Sensor nodes collect data from the physical world then exchange it until it reaches the intended destination. This information can be sensitive, such as battlefield surveillance. Therefore, providing secure and continuous data transmissions among sensor nodes in wireless network environments is crucial. Wireless sensor networks (WSN) have limited resources, limited computation capabilities, and the exchange of data through the air and deployment in accessible areas makes the energy, security, and routing major concerns in WSN. In this research we are looking at security issues for the above reasons. WSN is susceptible to malicious activities such as hacking and physical …

Scalable Multi-Hop Data Dissemination In Vehicular Ad Hoc Networks, Moumena Abdullah Chaqfeh

Dissertations

Vehicular Ad hoc Networks (VANETs) aim at improving road safety and travel comfort, by providing self-organizing environments to disseminate traffic data, without requiring fixed infrastructure or centralized administration. Since traffic data is of public interest and usually benefit a group of users rather than a specific individual, it is more appropriate to rely on broadcasting for data dissemination in VANETs. However, broadcasting under dense networks suffers from high percentage of data redundancy that wastes the limited radio channel bandwidth. Moreover, packet collisions may lead to the broadcast storm problem when large number of vehicles in the same vicinity rebroadcast nearly …

Selective Detection Of Volatile Organic Compounds Using Metal Oxide Sensor Arrays, Anton Dmitrievich Netchaev

Dissertations

Selective detection of organic contaminant using widely available and inexpensive metal oxide sensors has the potential to be used in various robotic platforms for navigation, harmful chemical leak detection, mobile environmental monitoring, etc. Selective gas detection in real world environments using easily available sensors has not been reported and can be used in many industries. A sensor system using only four commercially available sensors with accompanying signal conditioning and clustering algorithm capable of discriminatory detection of chemical marker is possible. Tests have shown that temperature, humidity and concentration fluctuations can be accounted for to produce systems for real world environments. …

Mechanochemical Investigation Of A Glassy Epoxy-Amine Thermoset Subjected To Fatigue, Stephen Finley Foster

Dissertations

Covalent bonds in organic molecules can be produced, altered, and broken through various sources of energy and processes. These include photochemical, thermochemical, chemical, and mechanochemical processes. Polymeric materials derive their physical properties from the time scale of motion, summation of intermolecular forces, and number of chain entanglements and crosslinks. Glassy thermoset polymers experience mechanical fatigue during dynamic stress loading and properties diminish with inevitable material failure at stress levels below the ultimate tensile strength (UTS). Damage modeling has been successful in predicting the number of cycles required to induce failure in a specimen due to stress. However, it does not …

Novel Spectroscopic Tools To Differentiate Molecule-Dna Binding Interactions, Sense Dna And Track Dna Melting, Saad Hmoud Alotaibi

Dissertations

The discovery of DNA as a genetic material and its double helical structure led to numerous studies directed at understanding molecule-DNA interactions. These studies have played an integral role in medical diagnostics, forensics, imaging and therapeutics. Typically, molecule-DNA interactions have two prominent modes: intercalation and minor groove binding. Several optical techniques are available that can monitor molecule-DNA binding interactions, but they cannot differentiate between intercalation and minor-groove binding. The major goals of the research are to develop novel optical spectroscopic tools that can differentiate molecule-DNA binding interactions, selectively and sensitively detect one form of DNA over another, and track DNA …

Integrating Formative Assessment Into Physics Instruction: The Effect Of Formative Vs. Summative Assessment On Student Physics Learning And Attitudes, Chaiphat Plybour

Dissertations

Of many instructional strategies used to improve teaching and learning in science, formative assessment is potentially one of the most effective. A central feature is timely feedback during learning, giving students the opportunity to benefit and improve while also enabling teachers to adjust instruction to learner needs. By contrast, conventional assessment tends to be mostly summative, assigning point scores, grading and ranking students, and providing extrinsic motivation. For maximum effectiveness in enhancing learning, formative assessment should be designed into instruction from the start rather than being an add-on. This project comprised development, teaching, and research aspects. Two physics topic modules, …

Aqueous Raft Polymerization Of Glycopolymers For Peptide Interaction Studies And Antimicrobial Peptide Mimics For Antimicrobial Activity And Selectivity Studies, Sarah Elizabeth Exley

Dissertations

The first section of this work describes the synthesis and characterization of novel glycopolymers synthesized to model GM1 gangliosides, a glycolipid found in neuronal cells. Glucose and galactose were attached to N-hydroxyethyl acrylamide, using chemistry that granted control over the stereochemistry at the C1’ carbon of each saccharide, and polymerized via aqueous RAFT (aRAFT). Homopolymers, targeting either 30 or 300 DP, and copolymers, with N-dimethyl acrylamide, were prepared as a glycopolymer platform for investigation of amyloid β (Aβ), a naturally occurring peptide associated with Alzheimer’s disease, aggregation. Aβ aggregation kinetics and aggregate size in the presence of glycopolymer were determined. …

Three Essays On Panel Data Estimation, Alexander Houser

Dissertations

This work discusses various aspects of panel data estimation. In chapter one, an algorithm for semiparametric random effects estimation is proposed. The performance of bootstrap-based confidence intervals for the proposed estimators are examined and found reasonable. The algorithm is also applied to a set of U.S. state level medical expenditure data to estimate the medical Engel curve. In the second chapter, the predictive performance of various parametric and semiparametric panel data estimators is compared on the same dataset of U.S. state level medical expenditures as well as out of sample forecast performance and bootstrap bias-corrected mean square errors of the …

Phantom Maps, Decomposability, And Spaces Meeting Particular Finiteness Conditions, James Schwass

Dissertations

The purpose of this dissertation is to extend principles for detecting the existence of essential phantom maps into spaces meeting particular finiteness conditions. Zabrodsky shows that a space Y having the homotopy type of a finite CW complex is the target of essential phantom maps if and only if Y has a nontrivial rational homology group. We show this observation holds on the collection of finite generalized CW complexes. Similarly, Iriye shows a finite-type, simply connected suspension space is the target of essential phantom maps if and only if it has a nontrivial rational homology group. We show this observation …

Improved Monitoring Of The Changjiang River Plume In The East China Sea During The Monsoon Season Using Satellite Borne L-Band Radiometers, Bumjun Kil

Dissertations

Measurement of sea surface salinity (SSS) from Satellite borne L-band (1.4 GHz, 21cm) radiometers (NASA Aquarius/SAC-D and ESA SMOS) in the East China Sea (ECS) is challenging due to the uncertainty of SSS caused by land thermal emissions in the antenna side lobes and because of strong radio frequency interference (RFI) due to illegally emitted man-made sources. RFI contamination in the ECS has gradually decreased because of the on-going international efforts to eliminate broadcasts in the protected L-band radio-astronomy frequency band. The present dissertation focuses on carefully eliminating the remaining RFI contamination in retrieved SSS, and masking out regions close …

Investigations Of The Photocatalytic Activity And Self-Cleaning Properties Of Polyhedral Oligomeric Silsesquioxane (Poss) Containing Titania Thiol-Ene Films, Lacrissia Unsonta Jefferson

Dissertations

In this document the film composition, self-cleaning aspect, photocatalytic efficiency, and methods employed to analyze a novel photocatalytic titania-containing thin film was evaluated. A primary objective of this research project was to assess the conditions required to achieve a stable titania dispersion for the photocatalytic coating and to determine the extent to which the presence of additives contributes to this process. Modified titania dispersions were prepared and characterized via dynamic light scattering (DLS), transmission electron microscopy (TEM), fourier transmission infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Characterization details of the previous focus on the influence of polyhedral oligomeric silsesquioxane (POSS) …

Wavelet Analysis Of Non-Stationary Signals With Applications, Maria Dorothea Van Der Walt

Dissertations

The empirical mode decomposition (EMD) algorithm, introduced by N.E. Huang et al in 1998, is arguably the most popular mathematical scheme for non-stationary signal decomposition and analysis. The objective of EMD is to separate a given signal into a number of components, called intrinsic mode functions (IMF's), after which the instantaneous frequency (IF) and amplitude of each IMF are computed through Hilbert spectral analysis (HSA). On the other hand, the synchrosqueezed wavelet transform (SST), introduced by I. Daubechies and S. Maes in 1996 and further developed by I. Daubechies, J. Lu and H.-T. Wu in 2011, is first applied to …

Mueller Matrix Spectroscopic Ellipsometry Of Multiferroics, Roman Basistyy

Dissertations

Multiferroics, materials which possess several ferroic orders, are the focus of research in recent years. Among these materials are oxide crystals, such as, for example, RMnO₃, RMn₂O₅, R₃Fe₅O₁₂, where R stands for rare earth ions. The most fascinating physics occurs when magnon-lattice coupling reveals itself in the far-IR spectra of multiferroics. The expected optical behavior puts multiferroics into a more general category of bi-anisotropic materials, the properties of which could be only described using anisotropic dielectric ε(ω), magnetic μ(ω), and …

Design And Analysis Of Algorithms For Similarity Search Based On Intrinsic Dimension, Xiguo Ma

Dissertations

One of the most fundamental operations employed in data mining tasks such as classification, cluster analysis, and anomaly detection, is that of similarity search. It has been used in numerous fields of application such as multimedia, information retrieval, recommender systems and pattern recognition. Specifically, a similarity query aims to retrieve from the database the most similar objects to a query object, where the underlying similarity measure is usually expressed as a distance function.

The cost of processing similarity queries has been typically assessed in terms of the representational dimension of the data involved, that is, the number of features used …

Local Selection Of Features And Its Applications To Image Search And Annotation, Jichao Sun

Dissertations

In multimedia applications, direct representations of data objects typically involve hundreds or thousands of features. Given a query object, the similarity between the query object and a database object can be computed as the distance between their feature vectors. The neighborhood of the query object consists of those database objects that are close to the query object. The semantic quality of the neighborhood, which can be measured as the proportion of neighboring objects that share the same class label as the query object, is crucial for many applications, such as content-based image retrieval and automated image annotation. However, due to …

Synthetic Approaches To The Understanding Of Dna Nucleobase Methylation, Jagruti Rana

Dissertations

DNA methylation is a major source of genetic variation and cancer. Methylation occurs when nucleophilic DNA bases react with methylating agent methyl methanesulfonate (MMS), dimethyl sulfate (DMS), N-methyl-N-nitrosourea (MNU), N-methyl-N-nitro-N-nitrosoguanidine (MNNG), etc. N7-methyl-2'-deoxyguanosine (N7-methyl-dG, or ^7MedG) adduct is the most abundant DNA methylation products for most methylating agents. DNA polymerase actions on ^7MedG are difficult to study due to its instability against ring- opening hydrolysis and deglycosyl ati on. Oligonucleotides containing a single chemical adduct of ^7MedG cannot be chemically synthesized. In addition, ^7MedG is unstable in vivo …

Location Reliability And Gamification Mechanisms For Mobile Crowd Sensing, Manoop Talasila

Dissertations

People-centric sensing with smart phones can be used for large scale sensing of the physical world by leveraging the sensors on the phones. This new type of sensing can be a scalable and cost-effective alternative to deploying static wireless sensor networks for dense sensing coverage across large areas. However, mobile people-centric sensing has two main issues: 1) Data reliability in sensed data and 2) Incentives for participants. To study these issues, this dissertation designs and develops McSense, a mobile crowd sensing system which provides monetary and social incentives to users.

This dissertation proposes and evaluates two protocols for location reliability …

Electronic, Thermoelectric And Optical Properties Of Vanadium Oxides: Vo2, V2o3 And V2o5, Chiranjivi Lamsal

Dissertations

Correlated electrons in vanadium oxides are responsible for their extreme sensitivity to external stimuli such as pressure, temperature or doping. As a result, several vanadium oxides undergo insulator-to-metal phase transition (IMT) accompanied by structural change. Unlike vanadium pentoxide (V₃O₃), vanadium dioxide (VO₃) and vanadium sesquioxide (V₃O₃) show I MT in their bulk phases. In this study, we have performed one electron Kohn-Sham electronic band-structure calculations of VO₃, V₃O₃ and V₂O₅ in both metallic and insulating phases, implementing a full ab-initio simulation package …

A Comprehensive Study Of Evolution Of Photospheric Magnetic Field And Flows Associated With Solar Eruptions, Shuo Wang

Dissertations

The rapid, irreversible change of the photospheric magnetic field has been recognized as an important element of the solar flare process. Recent theoretical work has shown that such a change would imply Lorentz force perturbations acting on both the outer solar atmosphere and the solar surface. This research uses vector magnetograms obtained with the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory to study a number of flares, which range from GOES-class C4 to X5 and occur in four active regions. In all the events, a permanent and rapid change of photospheric magnetic field closely associated with the …