Digital Commons Network^™

Modeling The Peak Absorption Of Meh-Ppv In Various Solvents Using Density Functional Theory, Corell H. Moore

Theses and Dissertations

Density Functional Theory (DFT) and time-dependent Density Functional Theory (TD-DFT) are powerful tools for modeling orbital energy in conjugated molecules and have been useful tools for research in organic photovoltaics. In this work, DFT is first used to explain the red shift in the absorption spectrum and increased absorption observed in MEH-PPV. Initially, the modeling of the red-shift in the absorption peak of MEH-PPV is studied using Gaussian 03 software with the global hybrid functional B3LYP for exchange-correlation and the 6-31G basis set. DFT and TD-DFT are used to separately study the effects of polymer chain length, carbon-carbon double-bond stretching, …

Mathematics Identity Construction In Successful African Americans: Reflections On Mathematics Experiences During Adolescence, Teri N. Johnson

Theses and Dissertations

This project used narrative inquiry to examine adolescent experiences that contributed to the development of positive mathematics identities in successful African Americans. Ten African Americans, who had worked in a STEM-related occupation for at least two years, were asked to reflect on in- and out-of-school experiences with mathematics during their middle and high school years. Data collection included individual interviews and one focus group discussion. A combination of internal and external factors emerged as contributors to participants’ adolescent mathematics identities. Internal factors included early career interest, finding enjoyment in the challenges associated with learning mathematics, or facing setbacks they were …

Eternal Enemies, Or Incidental Encounters? Structure And Patterns Of Interspecific Killing In Carnivora, Tor G. Bertin

Theses and Dissertations

Lethal interactions between carnivorans (interspecific killing) may influence their population dynamics, behavior, and other important aspects of their ecology. In this study, I expand upon previous research on the broad-scale patterns of interspecific killing in Carnivora (Palomares & Caro 1999, Donadio & Buskirk 2006) with a greatly expanded dataset (inclusion of scat and stomach data and more intensive sampling of the literature), and suggest avenues for future research. While like previous studies, I found a positive effect of relative body size between killer species and killed species on the likelihood of forming a killing interaction, I failed to find evidence …

Assessing The Quality Of Software Development Tutorials Available On The Web, Manziba A. Nishi

Theses and Dissertations

Both expert and novice software developers frequently access software development resources available on the Web in order to lookup or learn new APIs, tools and techniques. Software quality is affected negatively when developers fail to find high-quality information relevant to their problem. While there is a substantial amount of freely available resources that can be accessed online, some of the available resources contain information that suffers from error proneness, copyright infringement, security concerns, and incompatible versions. Use of such toxic information can have a strong negative effect on developer’s efficacy. This dissertation focuses specifically on software tutorials, aiming to automatically …

2nd Tier Assay For The Detection Of Congenital Adrenal Hyperplasia By Virginia’S Newborn Screening Laboratory: Steroid Profile By Hplc-Ms/Ms, Christopher E. Nixon

Theses and Dissertations

Congenital Adrenal Hyperplasia (CAH) encompasses several disorders related to disruptions in the adrenal steroid production pathway. These disruptions may cause virilization of the external female sex organs, incorrect gender assignment, precocious puberty, and in the most severe form, may cause life-threatening salt wasting and adrenal crisis if not detected and treated early in the newborn period.

17α-Hydroxyprogesterone (17-OHP) is the primary target for immunofluorescence detection of CAH from dried blood spots in newborn screening (NBS). Unfortunately, current immunoassay techniques for the detection of CAH suffer from high false positive rates. The primary factors contributing to false positive determinations can include …

Kings In The Direct Product Of Digraphs, Morgan Norge

Theses and Dissertations

A k-king in a digraph D is a vertex that can reach every other vertex in D by a directed path of length at most k. A king is a vertex that is a k-king for some k. We will look at kings in the direct product of digraphs and characterize a relationship between kings in the product and kings in the factors. This is a continuation of a project in which a similar characterization is found for the cartesian product of digraphs, the strong product of digraphs, and the lexicographic product of digraphs.

Explainable Neural Networks Based Anomaly Detection For Cyber-Physical Systems, Kasun Amarasinghe

Theses and Dissertations

Cyber-Physical Systems (CPSs) are the core of modern critical infrastructure (e.g. power-grids) and securing them is of paramount importance. Anomaly detection in data is crucial for CPS security. While Artificial Neural Networks (ANNs) are strong candidates for the task, they are seldom deployed in safety-critical domains due to the perception that ANNs are black-boxes. Therefore, to leverage ANNs in CPSs, cracking open the black box through explanation is essential.

The main objective of this dissertation is developing explainable ANN-based Anomaly Detection Systems for Cyber-Physical Systems (CP-ADS). The main objective was broken down into three sub-objectives: 1) Identifying key-requirements that an …

Spectral Methods For The Detection And Characterization Of Topologically Associated Domains, Kellen Garrison Cresswell

Theses and Dissertations

The three-dimensional (3D) structure of the genome plays a crucial role in gene expression regulation. Chromatin conformation capture technologies (Hi-C) have revealed that the genome is organized in a hierarchy of topologically associated domains (TADs), sub-TADs, and chromatin loops which is relatively stable across cell-lines and even across species. These TADs dynamically reorganize during development of disease, and exhibit cell- and conditionspecific differences. Identifying such hierarchical structures and how they change between conditions is a critical step in understanding genome regulation and disease development. Despite their importance, there are relatively few tools for identification of TADs and even fewer for …

Statistical Designs For Network A/B Testing, Victoria V. Pokhilko

Theses and Dissertations

A/B testing refers to the statistical procedure of experimental design and analysis to compare two treatments, A and B, applied to different testing subjects. It is widely used by technology companies such as Facebook, LinkedIn, and Netflix, to compare different algorithms, web-designs, and other online products and services. The subjects participating in these online A/B testing experiments are users who are connected in different scales of social networks. Two connected subjects are similar in terms of their social behaviors, education and financial background, and other demographic aspects. Hence, it is only natural to assume that their reactions to online products …

Applications Of Chemically Modified Nitrogen Doped Carbon, Zirconium Phosphate, Metal Organic Frameworks, And Functionalized Graphene Oxide Nanostructured Adsorbents In Water Treatment, Ayyob Mohammed A Bakry

Theses and Dissertations

Water contaminations by many pollutants, especially heavy metals such as Pb(II), Hg(II), Cu(II), Cd(II), and Cr(VI) pose many public health and environmental concerns as reported in the list of hazardous substances compiled by the US Environmental Protection Agency due to their high toxicity, refractory degradation, and ease of entering food chain. Adsorption by chelating resins is proven to be the most effective method for the extraction of metal ions from polluted and wastewater. However, traditional absorbents such as activated carbon, activated alumina, clay, zeolite, etc., show limited adsorption abilities for these heavy metal ions. The major goal of this thesis …

Policies And Procedures Perceived By School Leaders To Reduce Truancy In A Public Charter School, Alix Desulme

All Theses And Dissertations

This qualitative study examined the causes of student truancy and the policies and procedures established by one public charter school to reduce truancy. Eight participants were asked to discuss the policies and procedures of their school, CSS, and how they as school leaders contributed to the success of the school regarding low truancy rates. Student truancy has become a major concern in the United States with some states and some counties experiencing higher truancy rates than others. This study aimed to understand leaders’ perceptions of the effectiveness of truancy policies at their school. To understand what factors affected truancy at …

Applying Hierarchical Tag-Topic Models To Stack Overflow, John J. Coogle

Theses and Dissertations

Stack Overflow is a question and answer site for programming questions. It has become one of the most widely used resources for programmers, with many programmers accessing the site multiple times per day. A threat to the continued success of Stack Overflow is the ability to efficiently search the site. Existing research suggests that the inability to find certain questions results in
unanswered questions, long delays in answering questions, or questions which are unable to be found by future visitors to the site. Further research suggests that questions with poor tag quality are particularly vulnerable to these issues.

In this …

Elaborations On Multiattribute Utility Theory Dominance, David L. Vairo

Theses and Dissertations

ELABORATIONS ON MULTIATTRIBUTE UTILITY THEORY DOMINANCE

By David L. Vairo

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Virginia Commonwealth University, 2019.

Major Director: Dissertation director’s name, Dr. Jason Merrick, Supply Chain Management and Analytics

Multiattribute Utility Theory (MAUT) is used to structure decisions with more than one factor (attribute) in play. These decisions become complex when the attributes are dependent on one another. Where linear modeling is concerned with how factors are directly related or correlated with each other, MAUT is concerned with how a decision maker …

Elementary Teachers' Definitions And Usage Of Inquiry-Based Mathematics Instruction, Heather Nunnally

Theses and Dissertations

Current educational leaders call for students to build his or her own mathematical understanding from experiences, coupled with feedback from peers, teachers, and themselves and gain a conceptual understanding of mathematics. Researchers agree that inquiry in the elementary mathematics classroom can help increase conceptual understanding.

This case study focused on how elementary teachers define inquiry-based mathematics and implement it in their classrooms. Interviews, observations and lesson analysis were used to investigate what identities, relationships and activities look like in an elementary classroom that uses inquiry.

All of the participants felt "problem solving" and "working collaboratively" were essential for inquiry but …

Theoretical Studies Of The Structure And Stability Of Metal Chalcogenide Crntem (1≤N≤6, 1≤M≤8) Clusters, Fnu Sweta Prabha

Theses and Dissertations

In the presented work, first principle studies on electronic structure, stability, and magnetic properties of metal chalcogenide, Cr_nTe_m clusters have been carried out within a density functional framework using generalized gradient functions to incorporate the exchange and correlation effects. The energetic and electronic stability was investigated, and it was found that they are not always correlated as seen in the cluster Cr₆Te₈ which has smaller gap between its HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital) and a high electron affinity of 3.39 eV indicating lower electronic stability whereas higher fragmentation …

Optimizing Gas Mixture Composition For The Rtpc Detector For Bonus 12 At Jefferson Lab., Joshua H. Lehman

Theses and Dissertations

The main objective of this thesis is to perform a study of and optimize the most direct and practical gas mixture composition inside the Radial Time Projection Chamber for the Barely-Offshell Nucleon Structure (BONuS 12) detector for use in the CLAS 12 detector in Experimental Hall B at Thomas Jefferson National Accelerator Facility (JLab). The optimization of these conditions will enhance the performance and resolution of the detector. The original BONuS 6 experiment utilized a gas composition of 80 % He and 20% Dimethyl Ether (DME). With the extensive 12 GeV energy upgrade constructed at JLab and the new BONuS …

The Structure And Stability Of Cationic Metal-Benzene Clusters, Daniel P. Rabayda

Theses and Dissertations

We have investigated the size-dependent stability and structure of benzene, aluminum-benzene, and vanadium-benzene clusters. Motivated by gas-phase experimental studies performed by an experimental collaborator, we have used first-principle electronic structure methods to identify the structure of Al⁺(Bz)_n, V⁺(Bz)_n, and Bz_n clusters. Our studies reveal that cationic aluminum-benzene clusters have a magic number of 13, and that its high stability may be understood by analyzing the structure of the cluster. We also investigate the structure of vanadium-benzene clusters which have a magic number of 2. Here I examine the benzene-cation and benzene-benzene …

Some Intuition Behind Large Cardinal Axioms, Their Characterization, And Related Results, Philip A. White

Theses and Dissertations

We aim to explain the intuition behind several large cardinal axioms, give characterization theorems for these axioms, and then discuss a few of their properties. As a capstone, we hope to introduce a new large cardinal notion and give a similar characterization theorem of this new notion. Our new notion of near strong compactness was inspired by the similar notion of near supercompactness, due to Jason Schanker.

The Day Is Just Another Surface, Brooks M. Heintzelman

Theses and Dissertations

Within a practice founded on both typographic form and language, I have continued to push myself to make work that is more sensitive to place, more contextual, more (hopefully) generous toward a public audience. These pieces might serve as useful instruments of institutional critique, resources for comprehension, or moments in which to interrogate preconceived modes of seeing. I deploy original texts in public spaces in order that they might force viewers to decide how to personally resolve the content they encounter. Is it language or object? Literal or figurative? Graphic design or art? The further I develop this body of …

Class/Act Embodied Practices For Performative Pedagogy, Chauntee Irving

Theses and Dissertations

Class/Act: Embodied Practices for Performative Pedagogy is a personal and practical exploration of embodiment’s role in higher education acting pedagogy. In my thesis, I propose that embodied acting practices rooted in phenomenology and corporeal dramaturgy surpass conventional acting curricula. Embodied training is often confused with movement curricula and is regularly considered a shallow and/or unintelligent means to approaching acting work. However, I will argue the efficiency and effectiveness of embodied teaching techniques in four parts. Part One: Seeing is a retrospective of how my personal experiences outside of the classroom have drawn me toward embodied aesthetics. Part Two: Knowing unveils …

Determination Of Optimal Parameter Estimates For Medical Interventions In Human Metabolism And Inflammation, Marcella Torres

Theses and Dissertations

In this work we have developed three ordinary differential equation models of biological systems: body mass change in response to exercise, immune system response to a general inflammatory stimulus, and the immune system response in atherosclerosis. The purpose of developing such computational tools is to test hypotheses about the underlying biological processes that drive system outcomes as well as possible real medical interventions. Therefore, we focus our analysis on understanding key interactions between model parameters and outcomes to deepen our understanding of these complex processes as a means to developing effective treatments in obesity, sarcopenia, and inflammatory diseases.

We develop …

Computational And Experimental Investigation On The Wetting Behavior Of Droplet-Fiber Systems, Hossain Aziz

Theses and Dissertations

Interaction of a liquid droplet and a fiber or layer of fibers is ubiquitous in nature and in a variety of industrial applications. It plays a crucial role in fog harvesting, coalescence filtration, membrane desalination, self-cleaning and fiber based microfluidics, among many others. This work presents a quantitative investigation on the interactions of a droplet with a fiber or layers of fibers. More precisely, the present work is focused on 1) predicting the effects of fiber’s size and material on its ability to withhold a droplet against external forces and on the liquid residue left on the fiber after the …

Secure State Estimation In The Presence Of False Information Injection Attacks, Maitham Alsalman

Theses and Dissertations

In this dissertation, we first investigate the problem of source location estimation in wireless sensor networks (WSNs) based on quantized data in the presence of false information attacks. Using a Gaussian mixture to model the possible attacks, we develop a maximum likelihood estimator (MLE) to estimate the source location. The Cramer-Rao lower bound (CRLB) for this estimation problem is also derived.

Then, the assumption that the fusion center does not have the knowledge of the attack probability and the attack noise power investigated. We assume that the attack probability and power are random variables which follow certain uniform distributions. We …

Three Against Two: On The Difference Between Property And Contract And The Example Of Deposit Accounts In Bankruptcy, Jeanne L. Schroeder, David G. Carlson

Articles

In Citizen's Bank v. Strumpf (1995), Justice Scalia announced that deposit accounts are not "property". Five years later, the Uniform Commercial Code was amended to make deposit accounts collateral for the depositary bank maintaining the account, thereby crowding the field previously occupied by the common law right of setoff. Security interests attach to personal "property." Security interests attach to deposit accounts. Deposit accounts, by syllogistic logic, are property. Does this mean that the UCC has overruled the Supreme Court? We argue not. A deposit account is a mere contract in the two-person universe that contract law presupposes. A deposit account …

Exploring Wells-Dawson Clusters Associated With The Small Ribosomal Subunit, Debbie C. Crans, Irma Sánchez-Lombardo, Craig C. Mclauchlan

Faculty Publications – Chemistry

The polyoxometalate P2W18O626-, the Wells-Dawson cluster, stabilized the ribosome sufficiently for the crystallographers to solve the phase problem and improve the structural resolution. In the following we characterize the interaction of the Wells-Dawson cluster with the ribosome small subunit. There are 14 different P2W18O626- clusters interacting with the ribosome, and the types of interactions range from one simple residue interaction to complex association of multiple sites including backbone interactions with a Wells-Dawson cluster. Although well-documented that bridging oxygen atoms are the main basic sites on other polyoxometalate interaction with most proteins reported, the W=O groups are the main sites of …

Security Analysis Of The Internet Of Things Using Digital Forensic And Penetration Testing Tools, Olajide Ojagbule

College of Graduate Studies: Theses & Dissertations

We exist in a universe where everything is related to the internet or each other like smart TVs, smart telephones, smart thermostat, cars and more. Internet of Things has become one of the most talked about technologies across the world and its applications range from the control of home appliances in a smart home to the control of machines on the production floor of an industry that requires less human intervention in performing basic daily tasks. Internet of Things has rapidly developed without adequate attention given to the security and privacy goals involved in its design and implementation. This document …

Gallai-Ramsey Number For Classes Of Brooms, Benjamin J. Hamlin

College of Graduate Studies: Theses & Dissertations

Given a graph $G$, we consider the problem of finding the minimum number $n$ such that any $k$ edge colored complete graph on $n$ vertices contains either a rainbow colored triangle or a monochromatic copy of the graph $G$, denoted $gr_k(K_{3}:G)$. More precisely we consider $G=B_{m,\ell}$ where $B_{m,\ell}$ is a broom graph with $m$ representing the number of vertices on the handle and $\ell$ representing the number of bristle vertices. We develop a technique to reduce the difficulty of finding $gr_{k}(K_{3}:B_{m,\ell})$, and use the technique to prove a few cases with a fixed handle length, but arbitrarily many bristles. Further, …

Ifocus: A Framework For Non-Intrusive Assessment Of Student Attention Level In Classrooms, Narayanan Veliyath

College of Graduate Studies: Theses & Dissertations

The process of learning is not merely determined by what the instructor teaches, but also by how the student receives that information. An attentive student will naturally be more open to obtaining knowledge than a bored or frustrated student. In recent years, tools such as skin temperature measurements and body posture calculations have been developed for the purpose of determining a student's affect, or emotional state of mind. However, measuring eye-gaze data is particularly noteworthy in that it can collect measurements non-intrusively, while also being relatively simple to set up and use. This paper details how data obtained from such …

Blade Design And Analysis Of Horizontal-Axis Wind Turbine: Cfd And Experimental Investigation Of Blades Design, Relwinde Fabrice Zongo

College of Graduate Studies: Theses & Dissertations

The present thesis focuses on the investigations of the computational fluid dynamics analysis and the experimental study of small scales Horizontal Axis Wind Turbine (HAWT) blades. The initial steps are taken; in the process of this research were the selection of the airfoil type to be used in each blade design and the creation of a blade design with high efficiency operating in a low wind speed zone. For the mentioned blade design process, the following airfoils were selected respectively NACA 0010, NACA 0012, NACA 1412, NACA 2412, NACA 2414, NACA 4412 and NACA 6412. This selection intends to provide …

Quantification Of Aqp11 Paralog Expression In The Osmoregulatory Organs Of Anguilla Rostrata, Keith C. Kurt

College of Graduate Studies: Theses & Dissertations

Osmoregulation is facilitated by using an assortment of ion and water channels to assist acclimation to changing conditions and to maintain cellular homeostasis. Euryhaline fish can be found in both seawater and freshwater (SW and FW) environments. Expression of ion and water channels have been experimentally demonstrated to change as a fish acclimates to different environmental conditions. Relatively recently, a new group of water channels has been discovered that are primarily intracellular and includes aquaporin 11 (AQP11). Typically, AQPs are located on the cell plasma membrane to allow water to flow in and out of the cell by osmosis to …