Digital Commons Network^™

Qos In Sdn-Based Large-Scale Networks, Haitham Ghalwash

Doctoral Dissertations

Recent research has shown that the Software-Defined Networking (SDN) technology is a promising architecture providing abstraction and programmability of modern networks and enables a more efficient solution to many of the security, performance, management, and QoS issues. This dissertation researches and enriched SDN with an added level of QoS for network applications. Starting by investigating the potential of an SDN-based large-scale networked system, two topologies widely used in modern data centers, namely, Fat-tree and BCube, are considered. Their behavior and performance under different network scales, traffic loads, and traffic patterns are studied. Experimental results indicate the superiority of a …

Preservice Mathematics Teachers’ Development Of Open-Mindedness And Cultural Competence During An Education Abroad Program: A Qualitative Case Study, Blair Izard

Doctoral Dissertations

There is a long-standing issue in mathematics education regarding the support of equitable learning outcomes. As there has been significant attention from professional organizations, including NCTM and others, to address issues of access and equity within mathematics education, there has been an emphasis on creating mathematics classrooms that are responsive to students’ backgrounds, experiences, cultural perspectives, and traditions. However, in order to best meet these needs, we must prepare teachers that have a deep understanding of self, society, culture, and equity, which is no small challenge as it’s essentially calling for shifts in mathematics teachers’ identities. Experiential learning, in particular, …

Mesoscale Studies Of Nanostructured Multi-Functional Materials, Lukasz Kuna

Doctoral Dissertations

In this dissertation, multiple studies centered around functional properties of materials for applications in devices and novel technologies are carried out utilizing a mesoscale modeling approach. The studies involve simulating the properties of dielectric nano/microstructures with coupled polar and elastic degrees of freedom and developing a greater understanding of their dependence on the structure size, morphology and applied external conditions. Of particular focus in this work are optical properties of electroactive materials including zero- and one-dimensional structures such as nanoparticles and nanowires, as well as mesoscopic functional properties of larger structures such as polycrystalline ceramics (with submicron grain sizes) and …

One-Step Coassembly Of Nanocoatings And Effects Of The Deposition Methods, Sonia Chavez

Doctoral Dissertations

Organic/inorganic hybrid nanocoatings with a nacre like structure have attracted high interest because of their outstanding properties. A one-step coassembly method has previously been developed to prepare polyvinyl alcohol (PVA)/montmorillonite (MMT) nanocoatings with a high concentration of well-aligned MMT nanosheets. To obtained these coatings, dip coating is commonly used for flow-induced orientation.

In this dissertation, different coating methods are investigated to explore alternatives to overcome the deficiencies of dip coating. Spray coating is a versatile method that has virtually no limitation on substrate size or shape. Spray coating was varied through time and number of cycles. In addition, a rotational …

The Interactive Effects Of Titanium Dioxide Nanoparticles And Light On Coastal Planktonic Organisms, Vena Haynes

Doctoral Dissertations

Archival abstract submitted

The Parity-Violating Asymmetry In The N→Δ Transition At Low Q2, Thamraa A. Alshayeb

Doctoral Dissertations

Qweak has used the parity violating asymmetry to test the Standard Model (SM) by constantly flipping helicity states of a longitudinally polarized electron beam that scatters in the unpolarized LH2 target. The main focus of the Qweak experiment at Jefferson Lab was the recently published determination of the proton’s weak charge. In order to make corrections to the measured asymmetry at low 𝑄 2 due to inelastically scattered electrons, dedicated measurements were made of the parity violating asymmetry in the N→∆ transition at two different beam energies.

The measured inelastic asymmetries are used to extract the low energy constant dΔ, …

Coupling Micro/Nanoscale Electoporation To Enhance Genetic Probe Delivery For Cell Therapy, Xuan Liu

Doctoral Dissertations

Emerging as an effective option, immunotherapy is gradually being recognized by the cancer treatment community. However, due to its wide use of viral vectors for gene delivery, many limitations and safety concerns impede its adoption in clinical practice. This promotes the emergence of many non-viral gene delivery methods including the use of inorganic or organic nanoparticles to carry and deliver genetic probes as complexes through chemical mechanisms and the use of mechanical or electrical forces to physically breakdown delivery barriers of the cell membrane to allow quick probe internalization. Compared to the former (chemical methods), the latter (physical methods) shows …

Gene Editing In Mammalian Cells By Flp Recombinase Variants, Feng Li

Doctoral Dissertations

In this dissertation, DNA recombinase Flp modified variants were developed for gene editing. The Flp recombinases can perform recombination reactions to modify the DNA sequence on the Flp recombination target (FRT). The Flp can recognize the DNA sequences，which resemble the wild-type FRT when modified. The Flp modified variants show potential values for genomic engineering because such FRT-like sequences as targets are widespread in the human genome. Our goal is to evolve the Flp variants on FRT-like targets in the human genome for safety and efficiency, correcting the genome mutations which cause the genetic disease.

Gene editing relies on site specificity …

Multi-Model Network Intrusion Detection System Using Distributed Feature Extraction And Supervised Learning, Sangam Mulmi

Doctoral Dissertations

Intrusion Detection Systems (IDSs) monitor network traffic and system activities to identify any unauthorized or malicious behaviors. These systems usually leverage the principles of data science and machine learning to detect any deviations from normalcy by learning from the data associated with normal and abnormal patterns. The IDSs continue to suffer from issues like distributed high-dimensional data, inadequate robustness, slow detection, and high false-positive rates (FPRs). We investigate these challenges, determine suitable strategies, and propose relevant solutions based on the appropriate mathematical and computational concepts.

To handle high-dimensional data in a distributed network, we optimize the feature space in a …

Abc Method And Fractional Momentum Layer For The Fdtd Method To Solve The Schrödinger Equation On Unbounded Domains, Joshua Paul Wilson

Doctoral Dissertations

The finite­difference time­domain (FDTD) method and its generalized variant (G­FDTD) are efficient numerical tools for solving the linear and nonlinear Schrödinger equations because not only are they explicit, allowing parallelization, but they also provide high­order accuracy with relatively inexpensive computational costs. In addition, the G­FDTD method has a relaxed stability condition when compared to the original FDTD method. It is important to note that the existing simulations of the G­FDTD scheme employed analytical solutions to obtain function values at the points along the boundary; however, in simulations for which the analytical solution is unknown, theoretical approximations for values at points …

Stress Analysis Of Operating Gas Pipeline Installed By Horizontal Directional Drilling And Pullback Force Prediction During Installation, Hongfang Lu

Doctoral Dissertations

With the development of the natural gas industry, the demand for pipeline construction has also increased. In the context of advocating green construction, horizontal directional drilling (HDD), as one of the most widely utilized trenchless methods for pipeline installation, has received extensive attention in industry and academia in recent years. The safety of natural gas pipeline is very important in the process of construction and operation. It is necessary to conduct in-depth study on the safety of the pipeline installed by HDD method.

In this dissertation, motivated by the following considerations, two aspects of HDD installation are studied. First, through …

Influence Of Extracellular Cues Of Hydrogel Biomaterials On Stem Cell Fate, Haley Barnett

Doctoral Dissertations

The field of tissue engineering has developed to try and find an alternative approach to treat lost or damaged tissue. The field of tissue regeneration aims to develop tissue scaffolds composed of biomaterials, a cell source, and appropriate biochemical/phsysiochemical stimuli to replace current therapies. Stem cells offer great promise due to their self-renewal capabilities and their numerous differentiation possibilities. However, stem cells are extremely sensitive to their external environment which presents a challenge when culturing them on biomaterials. Surface elasticity, topography, surface chemistry, and exposure to biomolecules all represent environmental stimuli that could affect stem cell behavior. This research aims …

Human And Climate Impacts On Flooding Via Remote Sensing, Big Data Analytics, And Modeling, Eunsang Cho

Doctoral Dissertations

Over the last 20 years, the amount of streamflow has greatly increased and spring snowmelt floods have occurred more frequently in the north-central U.S. In the Red River of the North Basin (RRB) overlying portions of North Dakota and Minnesota, six of the 13 major floods over the past 100 years have occurred since the late 1990s. Based on numerous previous studies as well as senior flood forecasters’ experiences, recent hydrological changes related to human modifications [e.g. artificial subsurface drainage (SSD) expansion] and climate change are potential causes of notable forecasting failures over the past decade. My dissertation focuses on …

Novel Topologies In Polycyclic Aromatic Hydrocarbons: A Study Of Triangulenes And Other Molecular Shapes, Carter James Holt

Doctoral Dissertations

Triangulenes are the homologous series of triangle-shaped polycyclic aromatic hydrocarbons, first contemplated by chemists nearly 100 years ago. Computational models predict that triangulenes will be polyradicals, with high-spin electronic ground states. Recent technological advances have allowed the molecular-scale synthesis and on-surface characterization of the first three members of this series using atomic force microscopy techniques. In this work, a short and scalable synthesis of the [3]triangulene ring system was developed. Cascade cyclization of a tetra-benzyl alcohol precursor in trifluoromethanesulfonic acid solution gave the planar and three-fold symmetrical 4,8,12-trihydro[3]triangulenium carbocation. This new species has been characterized by NMR (nuclear magnetic resonance) …

An Asymptotic Self-Sustaining Process Theory For Uniform Momentum Zones And Internal Interfaces In Unbounded Couette Flow, Brandon Montemuro

Doctoral Dissertations

Meinhart \& Adrian (Phys. Fluids, vol. 7, 1995, p 694) were the first investigators to document that the wall-normal ($y$) structure of the instantaneous streamwise velocity in the turbulent boundary layer exhibits a staircase-like profile: regions of quasi-uniform momentum are separated by internal shear layers across which the streamwise velocity jumps by an O(1) amount when scaled by the friction velocity $u_\tau$. This sharply-varying instantaneous profile differs dramatically from the well-known long-time mean profile, which is logarithmic over much of the boundary layer, and prompted Klewicki (Proc. IUTAM, vol. 9, 2013, p. 69--78) to propose that the turbulent boundary layer …

Investigating The Spatial And Temporal Scale Variability Of Ebullitive Flux From A Subarctic Thaw Pond System, Sophia Burke

Doctoral Dissertations

Arctic regions are experiencing more rapid warming than other parts of the world, leading to destabilization of carbon (C) that has been sequestered in permafrost, especially in peatlands where the C content of the peat is very high. More frequent incidence of thaw in permafrost peatlands is leading to the development of small thaw ponds that are known to be sources of methane (CH4) to the atmosphere, yet there is a lack in long-term studies of CH4 emission from these formations. This is of concern because CH4 has thirty-two times the global warming potential of carbon dioxide over a one-hundred-year …

Element-Based Multi-Objective Optimization Methodology Supporting A Transportation Asset Management Framework For Bridge Planning And Programming, Karim Naji

Doctoral Dissertations

The Moving Ahead for Progress in the 21st Century Act (MAP-21) mandates the development of a risk-based transportation asset management plan and use of a performance-based approach in transportation planning and programming. This research introduces a systematic element-based multi-objective optimization (EB-MOO) methodology integrated into a goal-driven transportation asset management framework to

(1) improve bridge management,

(2) support state departments of transportation with their transition efforts to comply with the MAP-21 requirements,

(3) determine short- and long-term intervention strategies and funding requirements, and

(4) facilitate trade-offs between funding levels and performance.

The proposed methodology focuses on one transportation asset class (i.e., …

Am I A Math Or Science Person? How High School Students’ Attitudes Towards Mathematics And Science Influence Their Decision To Major In Stem, Dalton Dayne Marsh

Doctoral Dissertations

Motivated by an innovation-driven economy, critical emphasis has been placed on the science, technology, engineering, and mathematics (STEM) workforce in the United States. Education has been charged to prepare a diverse population of young people qualified to take up these jobs and lead the nation into a rapidly evolving technological future. How to best approach this goal is still being negotiated. While past research and efforts focused largely on improving students’ achievement in mathematics and science, more recent research points to the need to also consider students’ attitudes towards STEM subjects. However, what types of attitudes (e.g., self-efficacy, identity, interest, …

Modeling And Assessing The Sustainability Of Dams In The United States, Cuihong Song

Doctoral Dissertations

Dam decision-making is often controversial as a choice has to be made between the benefits provided by dams (e.g., recreation, water supply, hydropower) and their potential negative impacts (e.g., effects on natural flow regime, impediment for fish migration). However, our understandings of such tradeoffs under a full range of dam management alternatives remain limited which hinders our ability to make sound and scientifically defensible dam management decisions. The diverse stakeholders involved in the decision-making process with varying perspectives and preferences could further exacerbate the difficulty of decision-making. To advance our knowledge in sustainable dam decision-making, this dissertation developed modeling tools …

Understanding Earthquake Rupture Processes: Insights From Mid-Ocean Ridge Transform Faults And Submarine Volcanoes, Pamela Moyer

Doctoral Dissertations

Key goals of earthquake science are to understand properties that control where earthquakes start, stop and spread, as well as their ground shaking potential. Stress drop, proportional to slip over the rupture length, provides insight into how variations in material properties of the fault affect the slip behavior of earthquakes. Using data from two ocean bottom seismic experiments, this dissertation explores variations in stress drop in small to moderate magnitude earthquakes in two tectonic environments where heterogeneous fault zones are inferred. On Gofar Transform Fault on the East Pacific Rise, the largest earthquakes (6.0 ≤ MW ≤ 6.2) repeatedly rupture …

Development And Mechanistic Investigation Of Mixed Metal Oxides (Mmos) And Nanocomposites As Multi-Functional Catalysts, Laura Achola

Doctoral Dissertations

There are 4 chapters in this thesis. Chapter 1 presents photo-assisted PMS activation using cobalt doped mesoporous iron oxide with exceptional activity and stability up to 6 cycles and very low cobalt leaching. The effects of cobalt doping are shown using different characterization techniques. The high surface area and monomodal pore sizes are maintained with minimal cobalt incorporation. This study correlates the activity to increased labile oxygen induced by cobalt doping. Chapter 2 details the synthesis of mesoporous first–row transition metal ferrites. M²⁺ (Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn …

Development And Application Of Incompatible Graded Finite Elements For Analysis Of Nonhomogeneous Materials, Asmita Rokaya

Doctoral Dissertations

Functionally graded materials (FGMs) are non-homogenous and tailored to have a spatial variation of properties. The gradual modification of material properties is quite effective in reducing stresses. Finite element analysis of nonhomogeneous materials can be performed using an assemblage of either graded or homogeneous elements. A graded finite element samples the material property at more than one integration points, while a homogeneous element has constant property at all integration points based on the property of the element at the centroid. In this dissertation, a six-node incompatible graded finite element is developed.

This research aims to show significance of six-node incompatible …

The Equitable Leadership Practices Of Teacher Leaders In Secondary Science Instruction, Latanya T. Brandon

Doctoral Dissertations

The purpose of this case study is to investigate science teacher leadership for educational equity at the secondary school level during a period of reform. The current reform in science education acknowledges inequity and calls for significant changes in instruction (NRC, 2012). This study is designed to address two research questions: (1) ‘How do participants describe science teacher leaders’ educational practices for equity?’ and (2) ‘How are science teacher leaders’ equitable practices related to organizational structures and social norms within secondary schools?’. Three data sources: interviews, field observations, and artifacts, were collected and analyzed qualitatively. A social justice leadership framework …

Narrating Complexity In Latin America: Jorge Volpi, Roberto Bolaño, Valeria Luiselli, And Daniel Alarcón, Charles R. Lebel

Doctoral Dissertations

This dissertation examines the centrality of complex thought in examples of Latin American narrative produced since 1999. I am interested in the ways in which Jorge Volpi (Mexico City 1968), Roberto Bolaño (Santiago, Chile 1953), Valeria Luiselli (Mexico City 1983), and Daniel Alarcón (Lima, Peru 1977) address complex dynamics in contemporary human experience. My analysis focuses on thematic and narratological indicators of complex thought primarily in Volpi’s En busca de Klingsor (1999); Bolaño’s 2666 (2004); Luiselli’s Los ingrávidos (2011), La historia de mis dientes (2013), and Los niños perdidos (2016); and Alarcón’s podcast Radio Ambulante. I have chosen these …

Philippine Jesuit Schools Of Education: Heroic Institutions Of Learning And Leadership In Mission, Joaquin Jose Mari Casimiro Sumpaico

Doctoral Dissertations

Philippine Jesuit schools of education are important training sanctuaries for future teachers. These schools help build a nation by nurturing educators in their student years so that these said teacher-students may be equipped as they pursue their vocation of journeying with the Philippine youth towards meaningful and heroic learning. There is limited research on these Philippine Jesuit schools of education and how these have created an impact in Philippine nation-building. The qualitative research draws attention to the four pillars of Heroic Leadership in these schools of education. It will look for practices of Self-awareness, Ingenuity, Love, and Heroism in the …

Semiconductor Nanocrystals: Synthesis, Optical Properties And Environmental Impact, Xudong Wang

Doctoral Dissertations

The study in this dissertation mainly focused on semiconductor nanocrystals ranging from controllable synthesis of II-VI quantum dots in both organic phase and aqueous phase, to their optical property and potential environmental impact. Besides, our study of fluorescent nanomaterials was extended from semiconductor nanocrystals to another system, carbon dots. In the first project, an unconventional method to induce anisotropic growth of CdS arms on CdSe/CdS seeds was developed to form nanotetrapods. Our control experiments suggested the key role of CdS shell thickness of CdSe/CdS seeds and concentration of precursor for CdS growth in the growth of nanotetrapods. Our results show …

Complex Genome Analysis With High-Throughput Sequencing Data: Methods And Applications, Xin Li

Doctoral Dissertations

The genomes of most eukaryotes are large and complex. The presence of large amounts of non-coding sequences is a general property of the genomes of complex eukaryotes. High-throughput sequencing is increasingly important for the study of complex genomes. In this dissertation, we focus on two computational problems for high-throughput sequence data analysis, including detecting circular RNA and calling structural variations (especially deletions).

Circular RNA (or circRNA) is a kind of non-coding RNA, which consists of a circular configuration through a typical 5' to 3' phosphodiester bond by non-canonical splicing. CircRNA was originally thought as the byproduct from the process of …

Multi-Scale Modeling Of Nanoparticle-Mediated Drug Delivery, Zhiqiang Shen

Doctoral Dissertations

Using multi-scale molecular dynamics (MD) simulations, we systematically study the influences of nanoparticle (NP) properties (including size, shape, elasticity and surface functionality) on the endocytosis process. Furthermore, we use MD simulations to help design new liposome-like and pH-responsive NPs.

The endocytosis of elastic NPs is first investigated. With a new developed elastic NP model, we investigate NPs with different sizes, shapes, and stiffness. Our simulations provide clear evidence that the membrane wrapping efficiency of NPs is a result of competition between receptor diffusion kinetics and thermodynamic driving force. We further suggest that conflicting experimental observations on the endocytosis efficiency of …

Dynamic Resource Management In Lossy Real-Time Wireless Networks, Tao Gong

Doctoral Dissertations

Along with the rapid development of real-time wireless network (RTWN) technologies in a wide range of time- and safety-critical industrial applications, packet scheduling algorithms have been playing a critical role in RTWNs to achieve desired Quality of Service (QoS) for real-time sensing and control, especially in the presence of unexpected disturbances. Most existing solutions focus on communication schedule construction to meet the desired QoS but have common assumptions that all wireless links are reliable, and the network topologies are prior known. Although these assumptions simplify the algorithm design and analysis, they are not realistic in real world.

To relax the …

Effective Algorithms For The Closest Pair And Related Problems, Xingyu Cai

Doctoral Dissertations

The Closest Pair problem aims to identify the closest pair (using some similarity measure, e.g., Euclidean distance, Dynamic Time Warping distance, etc.) of points in a metric space. This is one of the fundamental problems that has a wide range of applications in the data mining area, since most of the data can be represented in a vector form residing in a high dimensional space, and we would like to identify the relationship among those data points. Typical applications include but not limited to, social data analysis, user pattern identification, motif mining in biological data, data clustering, etc. This is …