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The Fluid Dynamics Of A Spanwise-Morphing Wing: An Experimental And Analytical Study, Kamlesh Joshi Jan 2022

The Fluid Dynamics Of A Spanwise-Morphing Wing: An Experimental And Analytical Study, Kamlesh Joshi

Electronic Theses and Dissertations, 2020-2023

The unsteady forces and fluid flow structure of a morphing wing are investigated for low Reynolds number (Re) flows, i.e., Re < 20,000. The morphing wing is designed to change shape in the spanwise direction in a controlled manner using internal actuation. The two types of wing morphing are studied in this work, i.e., spanwise bending and spanwise twisting. The wing morphing is named based on the overall shape of the wing after it is dynamically morphed.

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Translations To Support Loop Invariant Generation In Jml, Kohei Koja Jan 2022

Translations To Support Loop Invariant Generation In Jml, Kohei Koja

Electronic Theses and Dissertations, 2020-2023

Software is used in many critical systems in the real world such as autonomous cars and medical devices. Such software must be reliable to protect the general public. One standard way to make reliable software is to use Hoare-style verification techniques. However, for Hoare-style verification of loop correctness, loop invariants are necessary but are difficult for people to write themselves. Since Java is one of the most popular programming languages in the world, it is useful to have a tool to generate loop invariants for Java programs. OpenJML is a widely used program verification tool for Java. However, it does …

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Investigating Covariate Selection Criteria: To Draw Causal Inferences From Observational Data In The Presence Of Unmeasured Covariates Using Regression And Propensity Score Methods, Uday Nair Jan 2022

Investigating Covariate Selection Criteria: To Draw Causal Inferences From Observational Data In The Presence Of Unmeasured Covariates Using Regression And Propensity Score Methods, Uday Nair

Electronic Theses and Dissertations, 2020-2023

The aim of causal effect estimation is to find the true impact of a treatment or exposure. Observational data is employed in social sciences to estimate causal effect but is susceptible to self-selection and unobserved confounding biases. Covariates included in analysis should strive to address these biases. This research focuses on investigating covariate selection approaches––common cause criterion (CC), Disjunctive Cause Criterion (DCC), Modified Disjunctive Cause Criterion (MDCC), and modified cause criterion (MCC)––in linear regression (LR) and propensity score methods (PSM) causal effect estimation in the presence of unmeasured confounding. Realistic social science scenarios such as––inclusion of proxy variables with varying …

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Exploration Of Shock-Droplet Ignition And Combustion, John Patten Jan 2022

Exploration Of Shock-Droplet Ignition And Combustion, John Patten

Electronic Theses and Dissertations, 2020-2023

Liquid fuels are desirable in aerospace applications due to their higher energy density when compared to gaseous fuels. With the advent of detonation-based engines, it is necessary to characterize and analyze how liquid fuel interacts with detonation waves as well as shocks to ignite. While liquid fuel sprays have been proven to successfully aid and sustain detonations, the physical mechanism by which the individual liquid droplets accomplish this is yet to be understood. Such knowledge allows for more predictable detonation properties, which in turn can let detonation-based engines be sustained more easily. This research seeks to quantify and characterize interactions …

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Effficient Graph-Based Computation And Analytics, Bingbing Rao Jan 2022

Effficient Graph-Based Computation And Analytics, Bingbing Rao

Electronic Theses and Dissertations, 2020-2023

With data explosion in many domains, such as social media, big code repository, Internet of Things (IoT), and inertial sensors, only 32% of data available to academic and industry is put to work, and the remaining 68% goes unleveraged. Moreover, people are facing an increasing number of obstacles concerning complex analytics on the sheer size of data, which include 1) how to perform dynamic graph analytics in a parallel and robust manner within a reasonable time? 2) How to conduct performance optimizations on a property graph representing and consisting of the semantics of code, data, and runtime systems for big …

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Towards Secure And Trustworthy Iot Systems, Lan Luo Jan 2022

Towards Secure And Trustworthy Iot Systems, Lan Luo

Electronic Theses and Dissertations, 2020-2023

The boom of the Internet of Things (IoT) brings great convenience to the society by connecting the physical world to the cyber world, but it also attracts mischievous hackers for benefits. Therefore, understanding potential attacks aiming at IoT systems and devising new protection mechanisms are of great significance to maintain the security and privacy of the IoT ecosystem. In this dissertation, we first demonstrate potential threats against IoT networks and their severe consequences via analyzing a real-world air quality monitoring system. By exploiting the discovered flaws, we can impersonate any victim sensor device and polluting its data with fabricated data. …

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A Study Of Microgravity On Fluid Transport Through Porous Structures In Microfluidic Devices, Sylvain Le Henaff Jan 2022

A Study Of Microgravity On Fluid Transport Through Porous Structures In Microfluidic Devices, Sylvain Le Henaff

Electronic Theses and Dissertations, 2020-2023

The objective of this study is to refine the understanding of micro-fluidics subject to micro-gravity in an attempt to support future space exploration efforts. A combination of experimental and numerical approaches were utilized to build a validated assessment approach. A quasi-pore geometry, inspired by CT scans of rat bones, was used in lieu of human bone structures. A quasi-1D assessment of the conservation of momentum was used to identify the dominant forces acting on the fluid at the operating length-scales. The dominant forces were surface tension, gravity, and shear stress. Experiments were conducted to visualize the flow moving through the …

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Computational And Experimental Studies Of Adsorption And Reactions On Molybdenum Nitride And Silica Covered Ruthenium Surfaces, Muhammad Sajid Jan 2022

Computational And Experimental Studies Of Adsorption And Reactions On Molybdenum Nitride And Silica Covered Ruthenium Surfaces, Muhammad Sajid

Electronic Theses and Dissertations, 2020-2023

Fundamental studies of material surfaces are of continued interest to the development and improvement of many modern technologies, e.g. catalysis, energy efficient electronics, and high-capacity batteries etc. This dissertation targets two distinct sets of molecule-surface interactions relevant to the continued development of structure-property correlations using tools from Density Functional Theory with added verification from ultrahigh vacuum surface-science experiments. These include Haber-Bosch interactions at molybdenum-nitride surfaces and separation-dependent interactions between simple aromatics and Ru(0001) used to model a metal contact of Organic Electronic Devices (OEDs). In the first study, we focus on computational modelling of nitrogen fixation reactions on Mo- and …

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Interactions Of Aerosol Droplets With Ventilated Airflows In The Context Of Airborne Pathogen Transmission, Steven Schroeder Jan 2022

Interactions Of Aerosol Droplets With Ventilated Airflows In The Context Of Airborne Pathogen Transmission, Steven Schroeder

Electronic Theses and Dissertations, 2020-2023

This multidisciplinary study provides a comprehensive visualization of airborne aerosols and droplets coming into contact with a crossflow of moving air utilizing both experimental particle measuring methods and multiphase computational fluids dynamics (CFD). The aim of this research is to provide a Eulerian visualization of how ventilation can alter the position and density of an aerosol cloud, with the goal of applying this information to our understanding of social distancing ranges within outdoor settings and ventilated rooms. The results indicate that even minor perpendicular crossflows across the trajectory of an aerosol cloud can greatly reduce both the linear displacement and …

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Innovation Resistance? Understanding Officer Attitudes Toward Police Innovation, Justin Smith Jan 2022

Innovation Resistance? Understanding Officer Attitudes Toward Police Innovation, Justin Smith

Electronic Theses and Dissertations, 2020-2023

Over the years, innovations such as community-oriented policing, problem-oriented policing, and crime analysis have helped police agencies control, reduce, and prevent crime and disorder, and improve police and community relations. However, research shows that some officers are resistant to using these innovations in practice. Few studies have examined the causal mechanisms behind innovation resistance. This doctoral dissertation details a study that utilized a mixed method approach to partially test a framework that encompassed two theories to explain officer resistance to innovation: The Model of Consumer Resistance to Innovation from the consumer psychology and marketing fields (Ram & Sheth, 1989), and …

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Towards Leveraging Sparse Infrared Datasets For Multiple View Synthesis, Few Shot Learning And Background Invariant Recognition, Maliha Arif Jan 2022

Towards Leveraging Sparse Infrared Datasets For Multiple View Synthesis, Few Shot Learning And Background Invariant Recognition, Maliha Arif

Electronic Theses and Dissertations, 2020-2023

This dissertation presents a study of various machine learning techniques for recognizing vehicular objects in infrared images. State of the art methods for computer vision have not been widely explored for this part of the electromagnetic spectrum (EM). Challenges that arise due to the dearth of infrared training images, terrain clutter, and thermal phenomenology have not been fully addressed. Infrared dataset collection and annotation is both difficult and expensive. What if there is a way we can generate infrared images and diminish the need for collecting data out in the field? Our first research study encompasses an encoder-decoder model that …

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The Parker Problem In Hall Magnetohydrodynamics Analytical And Numerical Solutions, Chad Malott Jan 2022

The Parker Problem In Hall Magnetohydrodynamics Analytical And Numerical Solutions, Chad Malott

Electronic Theses and Dissertations, 2020-2023

In this thesis we follow on the mathematical aspects of the previous work of Shivamoggi (2009) on the Parker problem in Hall magnetohydrodynamics (MHD). We will present an analysis involving detailed analytical and numerical solutions to the Parker problem in Hall MHD. We give an analytical formulation for the Parker problem in Hall MHD, involving an initial value problem (IVP) associated with a first order Riccati equation (RE). We present Mathematica software exact solutions directly with special functions and more straightforward solutions that use the change of variables and power series methods without special functions. We give an asymptotic formulation …

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Spatiotemporal Analysis Of Taxi And Transportation Network Companies (Tnc) Demand In The Wake Of Covid-19, Dewan Ashraful Parvez Jan 2022

Spatiotemporal Analysis Of Taxi And Transportation Network Companies (Tnc) Demand In The Wake Of Covid-19, Dewan Ashraful Parvez

Electronic Theses and Dissertations, 2020-2023

The objective of the thesis is to understand the factors affecting spatiotemporal ridehailing demand patterns as the COVID-19 pandemic has evolved. Specifically, the current study examines the key contributing factors of weekly ridehailing demand by employing Taxi and Transportation Network Companies (TNC) trip data from January 2019 through December 2020 for New York City. The ridehailing demand is partitioned across four time periods including Morning Peak, Morning Off Peak, Evening Peak and Evening Off Peak to accommodate for the time-of-day specific variations. Drawing on the high-resolution NYC data, the current study developed pooled spatial panel models to accommodate for the …

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Deep Learning Anomaly Detection Using Edge Ai, William Holdren Jan 2022

Deep Learning Anomaly Detection Using Edge Ai, William Holdren

Electronic Theses and Dissertations, 2020-2023

Deep learning anomaly detection is an evolving field with many real-world applications. As more and more devices continue to be added to the Internet of Things (IoT), there is an increasing desire to make use of the additional computational capacity to run demanding tasks. The increase in devices and amounts of data flooding in have led to a greater need for security and outlier detection. Motivated by those facts, this thesis studies the potential of creating a distributed anomaly detection framework. While there have been vast amounts of research into deep anomaly detection, there has been no research into building …

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Aerodynamic Characterization Of An Elliptical Fairing In The Wake Of A Bluff Body, Luis Amaya Jan 2022

Aerodynamic Characterization Of An Elliptical Fairing In The Wake Of A Bluff Body, Luis Amaya

Electronic Theses and Dissertations, 2020-2023

Aerodynamic optimization is a key step in designing planes, cars, and even buildings. Numerical modeling is used to automate the optimization process and can use different methods to iterate through designs. In this process, consideration of the starting design is paramount as a poor choice can use up computational time and effort. Often, these designs are made with the intention of being out in the open, for which studies on shape variations in freestream situations abound. However, for the case where an object must be placed in the wake of another, there is little research. The study presented here aims …

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Studying The Robustness Of Machine Learning-Based Malware Detection Models: Analysis, Design, And Implementation, Ahmed Abusnaina Jan 2022

Studying The Robustness Of Machine Learning-Based Malware Detection Models: Analysis, Design, And Implementation, Ahmed Abusnaina

Electronic Theses and Dissertations, 2020-2023

With the rise of the popularity of machine learning (ML), it has been shown that ML-based classifiers are susceptible to adversarial examples and concept drifting, where a small modification in the input space may result in misclassification. The ever-evolving nature of the data, the behavioral and pattern shifting over time not only lessened the trust in the machine learning output but also created a barrier for its usage in critical applications. This dissertation builds toward analyzing machine learning-based malware detection systems, including the detection and mitigation of adversarial malware examples. In particular, we first introduce two black-box adversarial attacks on …

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Graph Neural Networks For Improved Interpretability And Efficiency, Patrick Pho Jan 2022

Graph Neural Networks For Improved Interpretability And Efficiency, Patrick Pho

Electronic Theses and Dissertations, 2020-2023

Attributed graph is a powerful tool to model real-life systems which exist in many domains such as social science, biology, e-commerce, etc. The behaviors of those systems are mostly defined by or dependent on their corresponding network structures. Graph analysis has become an important line of research due to the rapid integration of such systems into every aspect of human life and the profound impact they have on human behaviors. Graph structured data contains a rich amount of information from the network connectivity and the supplementary input features of nodes. Machine learning algorithms or traditional network science tools have limitation …

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Balancing User Experience For Mobile One-To-One Interpersonal Telepresence, Kevin Pfeil Jan 2022

Balancing User Experience For Mobile One-To-One Interpersonal Telepresence, Kevin Pfeil

Electronic Theses and Dissertations, 2020-2023

The COVID-19 virus disrupted all aspects of our daily lives, and though the world is finally returning to normalcy, the pandemic has shown us how ill-prepared we are to support social interactions when expected to remain socially distant. Family members missed major life events of their loved ones; face-to-face interactions were replaced with video chat; and the technologies used to facilitate interim social interactions caused an increase in depression, stress, and burn-out. It is clear that we need better solutions to address these issues, and one avenue showing promise is that of Interpersonal Telepresence. Interpersonal Telepresence is an interaction paradigm …

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Modeling, Reconstruction, And Trend Analysis Of Global Storm Surges Using A Data-Driven Approach, Michael Getachew Tadesse Jan 2022

Modeling, Reconstruction, And Trend Analysis Of Global Storm Surges Using A Data-Driven Approach, Michael Getachew Tadesse

Electronic Theses and Dissertations, 2020-2023

Storm surge is the deadliest component of extreme sea levels with one of the highest global death tolls per event. Tide gauges are the primary sources for historical sea-level measurements from which storm surge data is extracted. However, tide gauges are unevenly distributed across the globe, and most records are short in length and have gaps; this creates a challenge to assess long-term trends and perform robust extreme value analysis. This dissertation introduces a data-driven storm surge modeling framework that trains statistical and machine learning models with atmospheric and oceanographic variables. Data-driven models (DDMs) are trained and validated for more …

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Enhancing The Decision-Making Process For Public-Private Partnerships' Concession Agreements: Socio-Economic Sustainability Approaches, Faisal Alghamdi Jan 2022

Enhancing The Decision-Making Process For Public-Private Partnerships' Concession Agreements: Socio-Economic Sustainability Approaches, Faisal Alghamdi

Electronic Theses and Dissertations, 2020-2023

Designing a concession for Public-Private Partnerships (PPP) agreements is a complicated process due to the number of variables that need to be considered. The PPP concession has many parameters and components, and a change in one component will considerably impact other components. Hence, the determination of the fair values of the concession components needs to be based on mutual benefits between the concession participants. The concession participants have different parts in the development of the concession; hence, they have different perspectives and goals. Therefore, the concession design needs to be constructed to balance the interests of the involved parties to …

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First And Third Order Susceptibility Of Organic Molecules, Hao-Jung Chang Jan 2022

First And Third Order Susceptibility Of Organic Molecules, Hao-Jung Chang

Electronic Theses and Dissertations, 2020-2023

Illuminating a material with intense laser excitation may change its properties and result in nonlinear absorption (NLA) and nonlinear refraction (NLR). In this dissertation we study the nonlinear absorption of organic compounds, the effect of extremely nondegenerate NLR in semiconductors, and the linear refractive index of organic solvents. In liquids, the refractive index has been studied for decades and different kinds of refractometers have been proposed. However, most of the reported values are in the visible region and only for commonly used solvents. We proposed a new interferometer-based refractometer that allows us to measure the refractive index from the visible …

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Computational Modeling Of Respiratory Airflow In Human Distal Airways Using Hybrid Lung Model, Adnan Islam Jan 2022

Computational Modeling Of Respiratory Airflow In Human Distal Airways Using Hybrid Lung Model, Adnan Islam

Electronic Theses and Dissertations, 2020-2023

A major challenge in the Computational Fluid Dynamics (CFD) modeling of the human respiratory system is the complex variation of geometric scale from the trachea to the peripheral airways. The current literature on image-based lung flow analysis is limited to a few (typically 5) generations beyond the trachea. Such studies, which are limited largely by computational intensity and computational cost, also have limited accuracy. In this study we propose a hybrid methodology that enables CFD analysis from the middle to the distal airways through to the alveolar level. A hybrid lung model is generated where the middle airways are reconstructed …

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The Narratives Of Latina Students Who Have Participated In Invention Education, Cristina Saenz Jan 2022

The Narratives Of Latina Students Who Have Participated In Invention Education, Cristina Saenz

Electronic Theses and Dissertations, 2020-2023

Less than 2% of patent holders in the United States identify as Latina. This statistic is problematic considering the increasing Latinx population and the empirical evidence which indicates the benefits of drawing on diverse perspectives in the invention ecosystem. In an effort to increase diversity among inventors and patent holders, K-12 programs have been created to provide opportunities for students to participate in the iterative and recursive processes of inventing. One example is the emerging field of invention education. Invention education is an educational approach which teaches students how to identify and solve problems within their communities. Little is known …

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Synergistic Impacts Of Climate Change And Human Induced Stressors On The Apalachicola Bay Food Web, Kira Allen Jan 2022

Synergistic Impacts Of Climate Change And Human Induced Stressors On The Apalachicola Bay Food Web, Kira Allen

Electronic Theses and Dissertations, 2020-2023

Apalachicola Bay, an estuary located in northwest Florida, is likely to experience an increase in climate change and human-induced stressors, such as sea level rise and changes in freshwater inflow, in the future. A coupled hydrodynamic and food web modeling approach was used to simulate future scenarios of low and high river flow and sea level rise in Apalachicola Bay from 2020 to 2049 and demonstrate the range of temporal and spatial changes in water temperature, salinity, fisheries species populations and the broader food web. Concurrent with model development, a survey of Apalachicola Bay stakeholders was conducted to assess stakeholder …

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Third Order Nonlinear Optics In Solids, Nicholas Cox Jan 2022

Third Order Nonlinear Optics In Solids, Nicholas Cox

Electronic Theses and Dissertations, 2020-2023

Nonlinear optical effects occur when strong electromagnetic waves induce changes in a medium that affect its own propagation or that of another wave. Third order optical nonlinearities scale linearly with irradiance and lead to effects like two-photon absorption and nonlinear refraction. This work focuses on the experimental and theoretical study of two-photon absorption in crystalline solids. We begin by detailing the quantum mechanical states of electrons in solids along with the computational approaches to calculate their band structure. Next, a theoretical model for the linear and nonlinear optical interaction of light with matter is presented in a many-body formalism. This …

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Bayesian Spatiotemporal Modeling With Gaussian Processes, Qing He Jan 2022

Bayesian Spatiotemporal Modeling With Gaussian Processes, Qing He

Electronic Theses and Dissertations, 2020-2023

Bayesian spatiotemporal models have been successfully applied to various fields of science, such as ecology and epidemiology. The complicated nature of spatiotemporal patterns can be well represented through priors such as Gaussian processes. This dissertation is focused on two applications of Bayesian spatiotemporal models: a) anomaly detection for spatiotemporal data with missingness and b) zero-inflated spatiotemporal count data analysis. Missingness in spatiotemporal data prohibits anomaly detection algorithms from learning characteristic rules and patterns due to the lack of most data. This project is motivated by a challenge provided by the National Science Foundation (NSF) and the National Geospatial-Intelligence Agency (NGA). …

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Using Simulation For Law Enforcement De-Escalation Training, Julie Kent Jan 2022

Using Simulation For Law Enforcement De-Escalation Training, Julie Kent

Electronic Theses and Dissertations, 2020-2023

Law enforcement needs simulation practice tailored to de-escalation skills. Law enforcement officers spend most of their training time practicing how to use force appropriately and very little time practicing how to avoid using force. There is little research into the best ways for law enforcement to reduce their use of force and the best ways to provide training to individuals to coach them to avoid using force. There are many training programs promoting de-escalation techniques, but there is little research into the effectiveness of these programs beyond the ability of individuals to perform the skills that are trained. There is …

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Authoring Tools For Augmented Reality Scenario Based Training Experiences, Andres Vargas Gonzalez Jan 2022

Authoring Tools For Augmented Reality Scenario Based Training Experiences, Andres Vargas Gonzalez

Electronic Theses and Dissertations, 2020-2023

Augmented Reality's (AR) scope and capabilities have grown considerably in the last few years. AR applications can be run across devices such as phones, wearables, and head-mounted displays (HMDs). The increasing research and commercial efforts in HMDs capabilities allow end users to map a 3D environment and interact with virtual objects that can respond to the physical aspects of the scene. Within this context, AR is an ideal format for in-situ training scenarios. However, building such AR scenarios requires proficiency in game engine development environments and programming expertise. These difficulties can make it challenging for domain experts to create training …

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Light Trapping Transparent Electrodes, Mengdi Sun Jan 2022

Light Trapping Transparent Electrodes, Mengdi Sun

Electronic Theses and Dissertations, 2020-2023

Transparent electrodes represent a critical component in a wide range of optoelectronic devices such as high-speed photodetectors and solar cells. Fundamentally, the presence of any conductive structures in the optical path leads to dissipation and reflection, which adversely affects device performance. Many different approaches have been attempted to minimize such shadowing losses, including the use of transparent conductive oxides (TCOs), metallic nanowire mesh grids, graphene-based contacts, and high-aspect ratio metallic wire arrays. In this dissertation I discuss a conceptually different approach to achieve transparent electrodes, which involves recapturing photons initially reflected by highly conductive electrode lines. To achieve this, light-redirecting …

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Change Point Detection For Streaming Data Using Support Vector Methods, Charles Harrison Jan 2022

Change Point Detection For Streaming Data Using Support Vector Methods, Charles Harrison

Electronic Theses and Dissertations, 2020-2023

Sequential multiple change point detection concerns the identification of multiple points in time where the systematic behavior of a statistical process changes. A special case of this problem, called online anomaly detection, occurs when the goal is to detect the first change and then signal an alert to an analyst for further investigation. This dissertation concerns the use of methods based on kernel functions and support vectors to detect changes. A variety of support vector-based methods are considered, but the primary focus concerns Least Squares Support Vector Data Description (LS-SVDD). LS-SVDD constructs a hypersphere in a kernel space to bound …

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