Digital Commons Network^™

Computational Study On The Acoustic Footprint Of Stenosis In Larger Arteries, Ahmed Abdelnabi

Theses and Dissertations

We identify a new (acoustic) frequency-stenosis relations whose frequencies fall within the recommended auscultation threshold for stethoscopy (< 120 Hz) in this study. We demonstrate that these relations can be used to extend the application of phonoangiography (the measurement of the degree of stenosis from bruits) to stethoscopes that are broadly available. The First relationship is successfully identified using an analysis limited to the acoustic signature of the von Karman vortex street, which we automatically isolate using a metric based on an area-weighted average of the Q-criteria for the post-stenotic region. Specifically, we conduct LES-CFD simulations on simplified 2D internal flow geometries that represent blood vessels with varying degrees of stenosis. Then, using the Ffowcs Williams-Hawkings (FW-H) equation, we extract their emitted acoustic signals, which we subtract from a pure signal (stenosis-free) at the same heart rate. Next, we transform this differential signal to the frequency domain and meticulously classify its acoustic signatures according to six stenosis-invariant flow phases of a cardiac cycle. Using our Q-criterion-based metric, we then automatically restrict our acoustic analysis to the noises emitted by the von Karman vortex street (phase 4). Our analysis of its acoustic signature demonstrates a strong linear relationship between the degree of steno- sis and its dominant frequency, which differs significantly from the break frequency and heart rate (previously identified dominant frequencies). For the Second relationship, we develop a frequency-stenosis scaling law for particularly supravalvular aortic stenosis that falls within the preferred frequency range (30-120 Hz) for echocardiography. We expand to 3D patient specific geometry using Simulia’s Living Heart Human Model (LHHM), which has an anatomically accurate aorta geometry. This LHHM geometry is modified with stenoses ranging from 30 to 80 percent (moderate to severe). For physiologically consistent hemodynamic boundary conditions, we expand the study to employ the Windkessel model, which has been implemented on Fluent using UDF. We demonstrate that physiological boundary conditions reduce simulation time significantly compared to static boundary conditions. The FW-H model extracted the flow-generated acoustic signal of the stenotic geometries and analysed it at clinically relevant receiver locations. A preferred receiver location consistent with clinical practise is determined, and a correlation between the degree of stenosis and the prevalent acoustic frequency (within the frequency range of 70-120 Hz) is established. The obtained second scaling law is shown to be clinically reliable in assessing stenotic severity. Future research will investigate incorporating the vibroacoustic role of adjacent organs and tissue to expand the clinical applicability of our findings. Expansion of clinical and numerical datasets will be pursued in future research to enhance the reliability of our scaling law, possibly by leveraging much-needed ML-based acceleration schemes.

An Ambiguous Hermeneutic: Doubleness In Ingmar Bergman’S Quest For Self, Ingy Aziz

Theses and Dissertations

One of the functions of art in all its forms is to provide the means for self-exploration and, in this way, to enable us to relate cultural representation to the question of meaning. The beauty of cinematic art is that it gives voice to our deepest and most profound concerns and enables us to bridge the gap between personal psychology and public understanding. As interpreters, we do not always unearth the answers that we seek, but we certainly gain more insight through delving into the minds of major filmmakers in the canon of modern cinema. This thesis is on the …

Failure Distributions For Parallel Dependent Identical Weibull Components, Gina S. Sigler

Theses and Dissertations

For a parallel system, when one component fails, the failure distribution of the remaining components will have an increased failure rate. This dissertation takes a novel approach to finding the associated failure distribution of the full system using ordinal statistic distributions for correlated Weibull components, allowing for unknown correlations between the dependent components. A Taylor series approximation is presented for the two component; system failure time distributions are also derived for two failures in a two component system, two failures in an n component system, three failures in a three component system, and k failures in an n component system. …

Quantitative Modeling Of Text-Based Intelligence Source Uncertainty, Adam D. Nesmith

Theses and Dissertations

An all-source intelligence analyst’s primary job is delivering timely, well-sourced assessments on relevant targets based on uncertain and incomplete information. Each assessment includes a likelihood that the assessment is true, and a confidence level based on the uncertainty of the sources used. Quantitative all-source intelligence analysis is not widely implemented despite the acknowledged limitations of qualitative intelligence assessments and the existence of proposed quantitative methods. This is due to the challenge of quantitatively representing uncertainty in text-based intelligence reporting (i.e., HUMINT, OSINT, SIGINT), which limits the effectiveness and usability of previously suggested methods. This research creates a novel framework for …

Emitter Selection Optimization For Passive Synthetic Aperture Radar, Mu Kim

Theses and Dissertations

Widely distributed modern communication networks provide excellent opportunities to share the spectrum for passive radar systems, of which emitter selection is a major consideration factor. This research introduces emitter selection problem space, which consists of three SAR processing domains, namely, Data Collection, Image and Mission Performance Domains. Quantitative links between these domains are critical to formulate an optimal emitter selection problem in the Data Collection Domain and/or Image Domain, which satisfies given mission requirements in Mission Performance Domain. This research examines the properties of the SAR processing domains to develop performance metrics in the Data Collection and Image Domains, whose …

Portfolio Optimization Using Value Focused Thinking, Tyler Martin

Theses and Dissertations

This thesis explores the application of Value Focused Thinking (VFT) and multi-objective portfolio optimization to create a well-aligned portfolio for an organization faced with over 50 alternatives and limited funding. A novel technique is proposed to develop an optimized portfolio based on VFT scores, utilizing heuristic approaches like evolutionary algorithms. The research outcomes include an optimized portfolio, the total value evaluation of alternatives, and a sensitivity analysis. The new approach outperforms the organization’s previous method, resulting in a portfolio that better addresses the organization’s core values and objectives, scoring 21.21% higher.

Design And Analysis Of Asymmetric “String-Of-Pearls” Common Repeating-Ground-Track Satellite Constellations For Missions Requiring Regional Coverage, Nathaniel Choo

Theses and Dissertations

Satellite constellation design must balance many factors that emerge from multiple sources, including environmental hazards and competing mission objectives. The dynamic nature of space systems makes the problem of ‘optimal’ satellite constellation design even more challenging. Restricting satellite constellation designs to predefined geometric frameworks can alleviate many challenges associated with the design problem; however, it raises an important question: which geometric framework performs best for each mission set? This research leverages simulations, metaheuristics, and mathematical programming techniques to address this question for missions focusing on Earth-observation of one or more regions.

First, this research captures the current state of satellite …

The Feasibility Of Using High Strength Stainless Steel In Pre-Stressing Applications, Rana Khaled Morsy

Theses and Dissertations

This paper evaluates the applicability of using a corrosion-resistant reinforcement high strength stainless steel strands (HSSS) Duplex 2205 in pre-stressing applications. HSSS-Duplex 2205 is a high performance steel which can be used as an alternative to the conventional carbon steel strands, for a better service life. The high strength and corrosion resistance of the material allows it to show its impressive performance in marine structural applications. Although the use of HSSS-Duplex 2205 could be initially costly; however, the improved durability and extended service life of the concrete structures using HSSS would require less life-cycle cost. Although there is a gap …

Examining The Determinants Of Timeliness In Crises Policy Responses: The Case Of Covid-19 In Egypt, Abdelhalim Abdalla

Theses and Dissertations

Timely responses to crises and pandemics play a significant role in navigating and minimizing the adverse impacts of such critical periods on the public and governments worldwide. COVID-19 could show and prove how a single virus originating in a single country can rapidly spread throughout the world, transforming an epidemic in China into a global pandemic. The virus caused more than 6.5 million deaths and around 660 million confirmed cases worldwide, according to the WHO, and sparked the worst economic catastrophe globally in more than a century, as estimated by the World Bank. Evidence suggests that the extent of the …

Nuclear Bluff Learning: Nuclear Signaling In Times Of Crisis, Dina Tawfik

Theses and Dissertations

The thesis investigates the role of nuclear signaling by adopting a comparative case study approach to compare between two nuclear alert crises that occurred during the Cold War and two nuclear alert crises that occurred post-Cold War. The case studies included are as follows: the 1969 US nuclear alert; the 1973 Middle East nuclear alert; the 2017 US-North Korean nuclear alert; and the 2022 Russian nuclear alert. I investigate why leaders choose to employ this tactic despite its conspicuous dangers, and more importantly, I draw comparisons and similarities between the case studies to analyze how the Cold War nuclear alert …

Proportionality V. Categorization: The Issue Of Judicial Balancing Of Rights, Akram Mohamed

Theses and Dissertations

The fact that there is a constant conflict between individual rights and state or social interests has historically provoked the question of how to balance or harmonize such conflicting interests? On what basis shall the legislator or the judge decide in favor of this or that right in his legislation or judgement? Where shall we, for example, draw the line between the right to freedom of expression and the right to protect one’s honor and reputation? How could the legislator find the compromise between the state duty to protect fetus life and its obligation not to interfere with woman’s right …

The Black Sea Matters Too: Understanding Türkiye’S Role In The Black Sea Region Through The Turkish Straits According To Regional Security Complex Theory, Allison Hart

Theses and Dissertations

This paper first establishes the Black Sea as a region according to regional security complex theory then defines Türkiye’s role within the region and the impact that the Turkish Straits have on maintaining regional security. Through constructivist approaches and regional security complex theory the paper critiques previously defined concepts pertaining to Türkiye’s role in the region and outlines perceived security threats within the Black Sea region. The use of threat perceptions as a means for analysis provides a unique constructivist approach on regional security complex theory allowing for a grounded research approach to regionalism in the Black Sea. The threat …

The Effect Of The Carbon Nanotubes’ Surface Area On The Morphology And Performance Of Cellulose Acetate Nanocomposite Membranes In Nanofiltration Applications, Nouran Elbadawi

Theses and Dissertations

Population increase and climate change have significantly affected the availability of fresh water for consumption. Studies by UNESCO showed that more than 28% of the world population didn’t have access to clean safe drinking water in 2020. This situation is expected to get more serious over the coming 30 years with the limited availability of natural fresh water sources. The need to find solutions from alternative non-freshwater resources for drinking or irrigation is becoming a necessity. Within the context of desalination technologies, thousands of investigations are conducted to find the cheapest most efficient way of water treatment aiming at expanding …

The Dual Education System In Egypt: The System's Challenges And The Way Forward, Raghda Khaled Mohamed

Theses and Dissertations

The technical education and vocational training (TVET) system is a model of education that is popular all over the world. It is implemented in several countries and consists of several models. One of these models is the dual educational system. It is one of the booming TVET educational models that are common in Europe, especially in Germany. Since Egypt adapted the German dual educational model since the 1990’s, this thesis discusses the dual educational system in Egypt through the lens of governance and quality management. Currently, Egypt is collaborating with several national and international policy advisors on enhancing the dual …

Mixed-Criticality Scheduling Using Reinforcement Learning, Omar Elseadawy

Theses and Dissertations

Mixed-criticality (MC) scheduling is necessary for many safety-critical real-time embedded systems, as a failure of high-criticality jobs could lead to fatal accidents. With the emergence of software technologies in software-defined vehicles in the automotive and avionics industries, studying Mixed-Critically (MC) systems is essential to their safety standards, similar to ISO26262. The real-time operation of MC systems makes it an inherently online problem, such that the scheduler is only aware of the jobs that are currently released at any point in time and has no knowledge of future jobs. Due to the overhead cost of preemption, this study focuses on enforcing …

Enhancing Construction Safety Training Of Bridges Using Augmented Reality And Virtual Reality, Mohamed Sherif Elrifaee

Theses and Dissertations

Infrastructure development projects are widely acknowledged as some of the most complex and challenging projects to undertake. The construction of bridges, in particular, has proven to be a significant safety risk for workers, with a considerable number of accidents reported on construction sites. There is a lack of comprehensive training programs specifically designed for bridge construction safety, and only a few studies have explored the use of both AR and VR to enhance safety training in construction. As such, this research aims to improve the safety of bridge construction sites through the implementation of Augmented Reality (AR) and Virtual Reality …

Catecholamine System Function Of The Medial Prefrontal Cortex Following Repetitive Mild Traumatic Brain Injury And The Use Of Benzoyl Chloride To Quantify And Identify Neurotransmitters, Leah Horvat

Theses and Dissertations

Traumatic brain injury (TBI) is a serious global health burden that causes a wide range of neurocognitive symptoms. These cognitive processes are regulated by catecholamine signaling within the prefrontal cortex (PFC) region of the brain. To quantify functional deficits in catecholamine signaling after TBI, norepinephrine (NE) and dopamine (DA) levels within the PFC were quantified from microdialysate samples using high-performance liquid chromatography coupled with electrochemical detection. A method for benzoyl chloride derivatization of neurotransmitters and analysis with liquid chromatography and tandem mass spectrometry instrumentation was also developed to detect and analyze these neurotransmitters. Overall, it was found that catecholamine signaling …

“I’M Now Always Thinking About Math”: Exploring Mathematics Identities, Beliefs, And Lived Experiences Through Ypar, Maya A. Severns

Theses and Dissertations

This youth participatory action research (YPAR) study employing survey and case study design sought to explore and document the influence of YPAR participation on Black and Latine high school students’ perceptions of their mathematics identity development, what they learned about their peers’ and their own mathematics perceptions and lived experiences, and their recommendations for change in their own school and mathematics education in general. Eight high school participants were invited to engage in 12 YPAR study sessions that drew on the literature of mathematics identity, equity in mathematics education, and YPAR and were grounded in a theoretical framework including culturally …

Exploring Senior Chemical Engineering Students’ Approach To Process Safety Decision Making, Jeffrey Saunders Stransky

Theses and Dissertations

Despite investments in chemical process safety education, evidence suggests that engineers’ decision making may contribute to process safety incidents. Currently, limited educational endeavors in process safety decision making exist, raising the need for a better understanding of how to prepare chemical engineering students for industry decisions. This dissertation fortifies current process safety education through three studies involving senior chemical engineering students. Study One developed the Engineering Process Safety Research Instrument (EPSRI) through exploratory and confirmatory factor analyses. Educators may use the EPSRI to evaluate their students’ moral development. Study Two evaluated a digital process safety game, Contents Under Pressure, on …

Estimating The Impact Of Intersection Traffic On Air Quality Emissions At Camden Cooper Medical Health Intersection Through The Integration Of Vissim/Moves Models, Kourtney Nicole Arena

Theses and Dissertations

Traffic emissions near intersections can increase significantly due to idling as well as stop-and-go traffic conditions. Increased emissions of pollutants like particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), and polycyclic aromatic hydrocarbons (PAHs) found in traffic exhaust deteriorate the health of the population that is exposed to them. Since general traffic emissions are increased by the stop-and-go conditions produced at intersections, PAH traffic emissions should also increase from intersection driving conditions. The intersection of Dr. Martin Luther King Jr. Blvd and Haddon Ave in Camden, NJ was identified as an ideal site to study PAH traffic emissions. To …

The Influence Inclusive Literature Circles With Multicultural Literature Has On The Self-Efficacies Of 4th Grade Students With Disabilities, Brianna Norcross

Theses and Dissertations

This study seeks to determine what happens to fourth grade students with disabilities reading self-efficacies when they participate in inclusive literature circles with multicultural literature. The purpose of this teacher research was to investigate strategies to improve reading self-efficacies of students with disabilities, investigating what would happen if students with disabilities were placed heterogeneously with their peers while reading books with characters with disabilities and how that influenced their reading self-efficacies. Four students with a disability were integrated with their general education peers in their inclusive classroom to participate in literature circles for four weeks. The multicultural books were books …

Acyl Derivatives Of Α-Hydroxyhippuric Acid: Comparison Of A Charged Substrate Vs A Neutral Substrate For The Aqueous Kinetics, Elise Kerkemeyer

Theses and Dissertations

The Nagorski group’s interest in carbinolamides stems from their role as an intermediate in the mechanism of the peptidylglycine-α-amidating monooxygenase (PAM) enzyme. Various carbinolamide roles have been studied as they pertain to biological processes, but no efforts have been put forth to understand how they react mechanistically. This group has set its focus on the kinetics of the breakdown of various carbinolamide derivatives in aqueous environments. The results gathered have been used to determine the mechanisms by which they break down in different regions of a full pH profile so that light may be shed on how to manipulate them …

How Female Bipoc Students At A Predominantly White Institution Think About Belonging: A Multiperspective Study, Delirio Juarez

Theses and Dissertations

Black, Indigenous, and People of Color (BIPOC) students at predominantly White institutions (PWIs) report decreased sense of belonging compared to White students (Hunn, 2014; Hurtado & Carter, 1997; Museus et al., 2018; Strayhorn, 2019). The study aimed to answer, "What are the daily lived experiences of BIPOC students at a PWI?" and "How do BIPOC students at a PWI describe feelings of belonging (if at all)?" The study was conducted at a private, religiously affiliated, PWI, in the Western United States. The University Belonging Questionnaire (Slaten et al., 2018) was used to sort students' feelings of belonging. Female participants who …

"I Think They're Poisoning My Mind": Understanding The Motivations Of People Who Have Voluntarily Adopted Secure Email, Warda Usman

Theses and Dissertations

Secure email systems that use end-to-end encryption are the best method we have for ensuring user privacy and security in email communication. However, the adoption of secure email remains low, with previous studies suggesting mainly that secure email is too complex or inconvenient to use. However, the perspectives of those who have, in fact, chosen to use an encrypted email system are largely overlooked. To understand these perspectives, we conducted a semi-structured interview study that aims to provide a comprehensive understanding of the mindsets underlying adoption and use of secure email services. Our participants come from a variety of countries …

Exploring Motivational Factors Related To Teachers’ Retention And Attrition In Urban Schools, Andrew Wintner

Theses and Dissertations

Retention of educators within urban settings is an essential consideration. More specifically, the retention of Black, Indigenous, and People of Color (BIPOC) educators within urban schools is of great importance as the demographic of students grows increasingly multicultural due to shifting demographic patterns within large urban cities. I explored educator perceptions of motivational factors associated with retention and attrition through the theoretical lens of Situated Expectancy Value Theory (SEVT). A convergent parallel mixed methods design was utilized. Semi-structured interviews (N = 18) occurred simultaneously to quantitative data collection using a 44-item survey (N = 53). Analyses of the …

The Connective Tissue Of Well-Developed Interests: A Case Study Of A Science Research Classroom, Deborah M. Brand

Theses and Dissertations

The purpose of this study was to examine ways that long-term interests in high school students could be inspired and facilitated in educational contexts. In particular, it explored how a high school Science Research (SR) program cultivated belonging and supported autonomy in ways that inspired and promoted well-developed individual interests. This type of interest is characterized by an enduring desire to pursue learning out of an intellectual and emotional need to gain understanding; it drives behavior, motivation, and cognition toward particular activities and ideas. Classroom belonging is derived from this sense of connection and purpose a student feels from the …

A Method Of Reconstructing Historical Destructive Landslides Using Bayesian Inference, Raelynn Wonnacott

Theses and Dissertations

Along with being one of the most populated regions of the world, Indonesia has one of the highest natural disaster rates worldwide. One such natural disaster that Indonesia is particularly prone to are tsunamis. Tsunamis are primarily caused by earthquakes, volcanoes, landslides and debris flows. To effectively allocate resources and create emergency plans we need an understanding of the risk factors of the region. Understanding the source events of destructive tsunamis of the past are critical to understanding the these risk factors. We expand upon previous work focusing on earthquake-generated tsunamis to consider landslide-generated tsunamis. Using Bayesian inference and modern …

Recommending Answers To Math Questions Using Kl-Divergence And The Approximate Xml Tree Matching Approach, Siqi Gao

Theses and Dissertations

Mathematics is the science and study of quality, structure, space, and change. It seeks out patterns, formulates new conjectures, and establishes the truth by rigorous deduction from appropriately chosen axioms and definitions. The study of mathematics makes a person better at solving problems. It gives someone skills that (s)he can use across other subjects and apply in many different job roles. In the modern world, builders use mathematics every day to do their work, since construction workers add, subtract, divide, multiply, and work with fractions. It is obvious that mathematics is a major contributor to many areas of study. For …

Dd Slug Migration: Mathematical Model And Numerical Results, Joy Song

Theses and Dissertations

Amoebae are commonly studied to understand embryogenesis, and the best-characterized amoebozoan species is Dictyostelium discoideum (Dd). Dd has a very simple life cycle with a range of developmental stages, among which we are most interested in the stage of a migrating slug. It has been observed that different sizes of Dd slugs maintain a proportional distribution of prestalk cells and prespore cells: prestalk cells occupy the anterior 20% of the slug, while prespore cells occupy the posterior 80%. However, it remains unknown how the migrating slug forms and preserves this anterior-posterior proportional pattern under so many different dynamics including cell …

Navigating Uncertainty: The Role Of Gold, Silver, Oil, Cryptocurrency, And Esg Indices In The Mena Region, Rahaf Zakaria Sakr

Theses and Dissertations

This study examines the effectiveness of various financial instruments as hedges and safe havens during different market conditions in the MENA region. It compares traditional safe-haven investments ( gold, silver, and oil) and non-traditional safe-havens (cryptocurrencies and ESG stocks) to determine which investments function better as hedges and safe havens during different market conditions. The data covers eight years, starting in 2015 and ending in early 2023. DCC GARCH is utilized to examine time variation in conditional correlations. This study finds that Gold, Silver, and cryptocurrency can be considered strong hedges to the MENA market on average and weak safe …