Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

University of Central Florida

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1891 - 1920 of 7697

Full-Text Articles in Entire DC Network

Energy-Optimal Guidance Of An Auv Under Flow Uncertainty And Fluid-Particle Interaction, Demuni Singith De Zoysa Abeysiriwardena Jan 2018

Energy-Optimal Guidance Of An Auv Under Flow Uncertainty And Fluid-Particle Interaction, Demuni Singith De Zoysa Abeysiriwardena

Electronic Theses and Dissertations

The work presented gives an energy-optimal solution to the guidance problem of an AUV. The presented guidance methods are for lower level control of AUV paths, facilitating existing global planning methods to be carried out comparatively more efficiently. The underlying concept is to use the energy of fluid flow fields the AUVs are navigating to extend the duration of missions. This allows gathering of comparatively more data with higher spatio-temporal resolution. The problem is formulated for a generalized two dimensional uniform flow field given a fixed final time and free end states. This allows the AUVs to navigate to certain …

Go to article

Applying Machine Learning Techniques To Analyze The Pedestrian And Bicycle Crashes At The Macroscopic Level, Md Sharikur Rahman Jan 2018

Applying Machine Learning Techniques To Analyze The Pedestrian And Bicycle Crashes At The Macroscopic Level, Md Sharikur Rahman

Electronic Theses and Dissertations

This thesis presents different data mining/machine learning techniques to analyze the vulnerable road users' (i.e., pedestrian and bicycle) crashes by developing crash prediction models at macro-level. In this study, we developed data mining approach (i.e., decision tree regression (DTR) models) for both pedestrian and bicycle crash counts. To author knowledge, this is the first application of DTR models in the growing traffic safety literature at macro-level. The empirical analysis is based on the Statewide Traffic Analysis Zones (STAZ) level crash count data for both pedestrian and bicycle from the state of Florida for the year of 2010 to 2012. The …

Go to article

A Psychophysical Approach To Standardizing Texture Compression For Virtual Environments, Jeremy Flynn Jan 2018

A Psychophysical Approach To Standardizing Texture Compression For Virtual Environments, Jeremy Flynn

Electronic Theses and Dissertations

Image compression is a technique to reduce overall data size, but its effects on human perception have not been clearly established. The purpose of this effort was to determine the most effective psychophysical method for subjective image quality assessment, and to apply those findings to an objective algorithm. This algorithm was used to identify the minimum level of texture compression noticeable to the human, in order to determine whether compression-induced texture distortion impacted game-play outcomes. Four experiments tested several hypotheses. The first hypothesis evaluated which of three magnitude estimation (ME) methods (absolute ME, absolute ME plus, or ME with a …

Go to article

Simultaneous Measurement Of Isotope-Free Tracer And Interdiffusion Coefficients In Sandwich Type Diffusion Couples, Esin Schulz Jan 2018

Simultaneous Measurement Of Isotope-Free Tracer And Interdiffusion Coefficients In Sandwich Type Diffusion Couples, Esin Schulz

Electronic Theses and Dissertations

The experimental determination of the tracer or self-diffusion coefficient as a function of composition can be quite burdensome in alloys since separate measurements must be carried out for each alloy composition. A new formalism recently developed by I.V. Belova, N.S. Kulkarni, Y.H. Sohn and G.E. Murch, based on linear response theory combined with the Boltzmann–Matano method allows determination of tracer and interdiffusion coefficients simultaneously from a single, isotope-free solid to solid diffusion couple experiment. In this study, for the first time, an experimental investigation with an analytical approach based on the new formalism has been carried out in the binary …

Go to article

A Decision Support Tool For Video Retinal Angiography, Sumit Laha Jan 2018

A Decision Support Tool For Video Retinal Angiography, Sumit Laha

Electronic Theses and Dissertations

Fluorescein angiogram (FA) is a medical procedure that helps the ophthalmologists to monitor the status of the retinal blood vessels and to diagnose proper treatment. This research is motivated by the necessity of blood vessel segmentation of the retina. Retinal vessel segmentation has been a major challenge and has long drawn the attention of researchers for decades due to the presence of complex blood vessels with varying size, shape, angles and branching pattern of vessels, and non-uniform illumination and huge anatomical variability between subjects. In this thesis, we introduce a new computational tool that combines deep learning based machine learning …

Go to article

Flutter Stability Of Shrouded Turbomachinery Cascades With Nonlinear Frictional Damping, Alex Torkaman Jan 2018

Flutter Stability Of Shrouded Turbomachinery Cascades With Nonlinear Frictional Damping, Alex Torkaman

Electronic Theses and Dissertations

Prediction of flutter in shrouded turbomachinery cascades is difficult due to i) coupling of aerodynamic drivers and structural dynamics of the cascade through shrouds, and ii) presence of nonlinear dry friction damping as a result of relative motion between adjacent shrouds. An analytical framework is developed in this dissertation to determine flutter stability of shrouded cascades with consideration of friction damping. This framework is an extension to the well-established energy method, and it includes all contributing factors affecting stability of the cascade such as aerodynamic excitation and the stabilizing effects of dry friction damping caused by nonlinear contact forces between …

Go to article

Environmental Physical-Virtual Interaction To Improve Social Presence With A Virtual Human In Mixed Reality, Kangsoo Kim Jan 2018

Environmental Physical-Virtual Interaction To Improve Social Presence With A Virtual Human In Mixed Reality, Kangsoo Kim

Electronic Theses and Dissertations

Interactive Virtual Humans (VHs) are increasingly used to replace or assist real humans in various applications, e.g., military and medical training, education, or entertainment. In most VH research, the perceived social presence with a VH, which denotes the user's sense of being socially connected or co-located with the VH, is the decisive factor in evaluating the social influence of the VH—a phenomenon where human users' emotions, opinions, or behaviors are affected by the VH. The purpose of this dissertation is to develop new knowledge about how characteristics and behaviors of a VH in a Mixed Reality (MR) environment can affect …

Go to article

A Localized Blended Rbf Collocation Method For Effective Shock Capturing, Michael Harris Jan 2018

A Localized Blended Rbf Collocation Method For Effective Shock Capturing, Michael Harris

Electronic Theses and Dissertations

Solving partial differential equations (PDEs) can require numerical methods, especially for non-linear problems and complex geometry. Common numerical methods used today are the finite difference method (FDM), finite element method (FEM) and the finite volume method (FVM). These methods require a mesh or grid before a solution is attempted. Developing the mesh can require expensive preprocessing time and the quality of the mesh can have major effects on the solution. In recent years, meshless methods have become a research interest due to the simplicity of using scattered data points. Many types of meshless methods exist stemming from the spectral or …

Go to article

Bio-Inspired Visual Servo Control Of A Picking Mechanism In An Agricultural Ground Robot, Sinem Gozde Defterli Jan 2018

Bio-Inspired Visual Servo Control Of A Picking Mechanism In An Agricultural Ground Robot, Sinem Gozde Defterli

Electronic Theses and Dissertations

For a recently constructed disease detection agricultural ground robot, the segregation of unhealthy leaves from strawberry plants is a major task of the robot's manipulation subsystem in field operations. In this dissertation, the motion planning of a custom-designed picking mechanism in the ground robot's subsystem is studied in two sections. First, a set of analytical, suboptimal semi-analytical and numerical algorithms are studied to solve the inverse kinematics problem of the handling mechanism in firm circumstances. These premeditated approaches are built on the computation of the joint variables by an identified 3D position data of the target leaf only. The outcomes …

Go to article

In-Memory Computing Using Formal Methods And Paths-Based Logic, Alvaro Velasquez Jan 2018

In-Memory Computing Using Formal Methods And Paths-Based Logic, Alvaro Velasquez

Electronic Theses and Dissertations

The continued scaling of the CMOS device has been largely responsible for the increase in computational power and consequent technological progress over the last few decades. However, the end of Dennard scaling has interrupted this era of sustained exponential growth in computing performance. Indeed, we are quickly reaching an impasse in the form of limitations in the lithographic processes used to fabricate CMOS processes and, even more dire, we are beginning to face fundamental physical phenomena, such as quantum tunneling, that are pervasive at the nanometer scale. Such phenomena manifests itself in prohibitively high leakage currents and process variations, leading …

Go to article

Analysis Of Large-Scale Population Genetic Data Using Efficient Algorithms And Data Structures, Ardalan Naseri Jan 2018

Analysis Of Large-Scale Population Genetic Data Using Efficient Algorithms And Data Structures, Ardalan Naseri

Electronic Theses and Dissertations

With the availability of genotyping data of very large samples, there is an increasing need for tools that can efficiently identify genetic relationships among all individuals in the sample. Modern biobanks cover genotypes up to 0.1%-1% of an entire large population. At this scale, genetic relatedness among samples is ubiquitous. However, current methods are not efficient for uncovering genetic relatedness at such a scale. We developed a new method, Random Projection for IBD Detection (RaPID), for detecting Identical-by-Descent (IBD) segments, a fundamental concept in genetics in large panels. RaPID detects all IBD segments over a certain length in time linear …

Go to article

Investigation Of A Self-Powered Fontan Concept Using A Multiscale Computational Fluid-Structure Interaction Model, Kyle Beggs Jan 2018

Investigation Of A Self-Powered Fontan Concept Using A Multiscale Computational Fluid-Structure Interaction Model, Kyle Beggs

Electronic Theses and Dissertations

Congenital Heart Disease (CHD) occurs in about 1\% (40,000) of newborn babies each year in the United States alone. About 10.9\% (960) of whom suffer from Hypoplastic Left Heart Syndrome (HLHS) - a subset of CHD where children are born with a single-ventricle (SV). A series of three surgeries are carried out to correct HLHS culminating in the Fontan procedure where venous flow returns passively to the lungs. The current configuration for the Fontan results in elevated Central Venous Pressure (CVP), inadequate ventricular preload, and elevated Pulmonary Vascular Resistance (PVR) leading to a barrage of disease. To alleviate these complications, …

Go to article

Analytical And Numerical Investigations Of The Kudryashov Generalized Kdv Equation, William Hilton Jan 2018

Analytical And Numerical Investigations Of The Kudryashov Generalized Kdv Equation, William Hilton

Electronic Theses and Dissertations

This thesis concerns an analytical and numerical study of the Kudryashov Generalized Korteweg-de Vries (KG KdV) equation. Using a refined perturbation expansion of the Fermi-Pasta-Ulam (FPU) equations of motion, the KG KdV equation, which arises at sixth order, and general higher order KdV equations are derived. Special solutions of the KG KdV equation are derived using the tanh method. A pseudospectral integrator, which can handle stiff equations, is developed for the higher order KdV equations. The numerical experiments indicate that although the higher order equations exhibit complex dynamics, they fail to reach energy equipartition on the time scale considered.

Go to article

Monolithically Integrated Wavelength Tunable Laser Diode For Integrated Optic Surface Plasmon Resonance Sensing, Thamer Tabbakh Jan 2018

Monolithically Integrated Wavelength Tunable Laser Diode For Integrated Optic Surface Plasmon Resonance Sensing, Thamer Tabbakh

Electronic Theses and Dissertations

In this work, we demonstrate an InGaAsP multiple quantum well tunable laser diode that amalgamates two gain sections with different bandgap energies. This is achieved using selective area intermixing of the multiple quantum wells, and impurity-free vacancy induced disordering. When different current combination is injected into each section, that leads to a laser wavelength peak whose position depends on the relative magnitudes of the two injected currents. The laser wavelength can be fine-tuned from 1538 nm to 1578 nm with relatively constant output power. The free spectral range FSR of the tunable laser found to be 0.25 nm. This tunable …

Go to article

Fusing Freight Analysis Framework And Transearch Data: An Econometric Data Fusion Approach, Salah Uddin Momtaz Jan 2018

Fusing Freight Analysis Framework And Transearch Data: An Econometric Data Fusion Approach, Salah Uddin Momtaz

Electronic Theses and Dissertations

A major hurdle in freight demand modeling has always been the lack of adequate data on freight movements for different industry sectors for planning applications. Freight Analysis Framework (FAF), and Transearch (TS) databases contain annualized commodity flow data. The primary motivation for our study is the development of a fused database from FAF and TS to realize transportation network flows at a fine spatial resolution (county-level) while accommodating for production and consumption behavioral trends (provided by TS). Towards this end, we formulate and estimate a joint econometric model framework grounded in maximum likelihood approach to estimate county-level commodity flows. The …

Go to article

Analysis Of Driver Behavior Modeling In Connected Vehicle Safety Systems Through High Fidelity Simulation, Ahura Jami Jan 2018

Analysis Of Driver Behavior Modeling In Connected Vehicle Safety Systems Through High Fidelity Simulation, Ahura Jami

Electronic Theses and Dissertations

A critical aspect of connected vehicle safety analysis is understanding the impact of human behavior on the overall performance of the safety system. Given the variation in human driving behavior and the expectancy for high levels of performance, it is crucial for these systems to be flexible to various driving characteristics. However, design, testing, and evaluation of these active safety systems remain a challenging task, exacerbated by the lack of behavioral data and practical test platforms. Additionally, the need for the operation of these systems in critical and dangerous situations makes the burden of their evaluation very costly and time-consuming. …

Go to article

Electrospray And Superlens Effect Of Microdroplets For Laser-Assisted Nanomanufacturing, Eduardo Castillo Orozco Jan 2018

Electrospray And Superlens Effect Of Microdroplets For Laser-Assisted Nanomanufacturing, Eduardo Castillo Orozco

Electronic Theses and Dissertations

Nanoparticles of various materials are known to exhibit excellent mechanical, chemical, electrical, and optical properties. However, it is difficult to deposit and transform nanoparticles into large two-dimensional and three-dimensional structures, such as thin films and discrete arrays. Electrospray technology and laser heating enable the deposition of these nanoparticles through the dual role of microdroplets as nanoparticle carriers and superlenses. The main goals of this dissertation are to delineate the electrospray modes, to achieve subwavelength focusing, and to enable a process for the deposition of nanoparticles into microlayers and discrete nanodots (a nanodot is a cluster of nanoparticles) on rigid and …

Go to article

Modeling The Standard And Poor's 500 Index Via Wave Analytics: Harnessing Lag For Intraday Utilizations, John Cardenas Jan 2018

Modeling The Standard And Poor's 500 Index Via Wave Analytics: Harnessing Lag For Intraday Utilizations, John Cardenas

Electronic Theses and Dissertations

Modeling and simulation of financial instruments is accomplished from multiple approaches but most completely from an engineering perspective. Aeronautical engineering yields a wave model created for stock indices in the 1970s. This comprehensive methodology models stock markets as waves for the intention of trading or investing yet has not been applied on time periods smaller than daily or weekly, known as intraday. Stakeholders trading intraday waves need to utilize wave analysis for price capture, analytics, and profitability. It is the purpose of this thesis to present a model to harness wave analytics for the needs of traders seeking price capture …

Go to article

Psychophysiology Meets Computer Science: Predicting The Magnitude Of Participant Physiological Response With Machine Learning, Avonie Parchment Jan 2018

Psychophysiology Meets Computer Science: Predicting The Magnitude Of Participant Physiological Response With Machine Learning, Avonie Parchment

Electronic Theses and Dissertations

The present inquiry uses methods from psychophysiology and machine learning to reduce overall error in classification models. The field of psychophysiology, though rooted in decades of experimentation, has never reached the same level of precision as some aspects of medical inquiry. In fact, while some medical regression models, when determining some way to classify a patient's illness based on certain symptoms, can result in highly significant results with large effect sizes, equal levels are virtually unheard of in psychophysiology. The present investigation attempts to unravel some part of this mystery and determines some possible reasons for the difficulty in finding …

Go to article

Applied Software Tools For Supporting Children With Intellectual Disabilities, Ahmad Abualsamid Jan 2018

Applied Software Tools For Supporting Children With Intellectual Disabilities, Ahmad Abualsamid

Electronic Theses and Dissertations

We explored the level of technology utilization in supporting children with cognitive disabilities at schools, speech clinics, and with assistive communication at home. Anecdotal evidence, literature research, and our own survey of special needs educators in Central Florida reveal that use of technology is minimal in classrooms for students with special needs even when scientific research has shown the effectiveness of video modeling in teaching children with special needs new skills and behaviors. Research also shows that speech and language therapists utilize a manual approach to elicit and analyze language samples from children with special needs. While technology is utilized …

Go to article

Examining Users' Application Permissions On Android Mobile Devices, Muhammad Safi Jan 2018

Examining Users' Application Permissions On Android Mobile Devices, Muhammad Safi

Electronic Theses and Dissertations

Mobile devices have become one of the most important computing platforms. The platform's portability and highly customized nature raises several privacy concerns. Therefore, understanding and predicting user privacy behavior has become very important if one is to design software which respects the privacy concerns of users. Various studies have been carried out to quantify user perceptions and concerns [23,36] and user characteristics which may predict privacy behavior [21,22,25]. Even though significant research exists regarding factors which affect user privacy behavior, there is gap in the literature when it comes to correlating these factors to objectively collected data from user devices. …

Go to article

Passive Voice Usage In Undergraduate Stem Textbooks, Huiyuan Luo Jan 2018

Passive Voice Usage In Undergraduate Stem Textbooks, Huiyuan Luo

Electronic Theses and Dissertations

The present study, a corpus-based quantitative analysis, investigated the use of passive voice in terms of percentage (percentage of total passive usage), constructions (the most commonly used passive forms), and dispersion (the verbs that tended to be associated with passive usage) in college STEM textbooks, more specifically in Science, Technology, Engineering, and Mathematics. The corpus consisted of twenty textbooks with over 1 million running words selected from the textbooks' chapters. By identifying the main verbs and passive verbs used in the textbooks, the percentage of passive voice usage was calculated. The statistical difference of passive constructions between disciplines was examined …

Go to article

Exploring Fpga Implementation For Binarized Neural Network Inference, Li Yang Jan 2018

Exploring Fpga Implementation For Binarized Neural Network Inference, Li Yang

Electronic Theses and Dissertations

Deep convolutional neural network has taken an important role in machine learning algorithm. It is widely used in different areas such as computer vision, robotics, and biology. However, the models of deep neural networks become larger and more computation complexity which is a big obstacle for such huge model to implement on embedded systems. Recent works have shown the binarized neural networks (BNN), utilizing binarized (i.e. +1 and -1) convolution kernel and binarized activation function, can significantly reduce the parameter size and computation cost, which makes it hardware-friendly for Field-Programmable Gate Arrays (FPGAs) implementation with efficient energy cost. This thesis …

Go to article

Numerical Study Of Interfacial Flow Using Algebraic Coupled Level Set-Volume Of Fluid (A-Clsvof) Method, Majid Haghshenas Jan 2018

Numerical Study Of Interfacial Flow Using Algebraic Coupled Level Set-Volume Of Fluid (A-Clsvof) Method, Majid Haghshenas

Electronic Theses and Dissertations

Solving interfacial flows numerically has been a challenge due to the lack of sharpness and the presence of spurious currents at the interface. Two methods, Algebraic Coupled Level Set-Volume of Fluid (A-CLSVOF) method and Ghost Fluid Method (GFM) have been developed in the finite volume framework and employed in several interfacial flows such as Rayleigh-Taylor instability, rising bubble, impinging droplet and cross-flow oil plume. In the static droplet simulation, A-CLSVOF substantially reduces the spurious currents. The capillary wave relaxation shows that this method delivers results comparable to those of more rigorous methods such as Front Tracking methods for fine grids. …

Go to article

Narrative Transportation And Virtual Reality: Exploring The Immersive Qualities Of Social Justice In The Digital World, Sara Raffel Jan 2018

Narrative Transportation And Virtual Reality: Exploring The Immersive Qualities Of Social Justice In The Digital World, Sara Raffel

Electronic Theses and Dissertations

This dissertation explores the potential applications for virtual reality (VR) stories in support of social justice causes, examining whether digital games historically been successfully leveraged for social justice purposes, and determining which components of VR technology can most encourage narrative transportation of participants in VR stories. The first chapter examines theories of simulation, virtual reality, narrative, and interactivity, as well as concepts of immersion from various disciplines and settles on narrative transportation, a theory from cognitive psychology, as the most useful in measuring the effect of VR stories on participants. The second chapter examines ethnographic practices, activist games, and modes …

Go to article

Hole Selective Tunneling Oxide Applications With Insight Into Sophisticated Characterization Techniques, Nizamettin Kortan Ogutman Jan 2018

Hole Selective Tunneling Oxide Applications With Insight Into Sophisticated Characterization Techniques, Nizamettin Kortan Ogutman

Electronic Theses and Dissertations

Tunneling metal oxide layers combined with industrially applicable novel cleaning methods can boost the current efficiency limit, which corresponds to approximately %22 in production, of crystalline silicon (c-Si) solar cells. Within the scope of this dissertation, extremely thin tunneling layers (1-3nm) of aluminum oxide is studied in conjunction with the development of wet cleaning procedures that are feasible in production lines currently exist today. These tunneling stacks are deployed to serve as exceptional surface passivation layers due to the inherent built-in charge provided by aluminum oxide. This capability is further strengthened by the introduction of extremely well controlled wet chemical …

Go to article

Undergraduate Student Agreement With Reformed Introductory Physics Classes, Matthew Wilcox Jan 2018

Undergraduate Student Agreement With Reformed Introductory Physics Classes, Matthew Wilcox

Electronic Theses and Dissertations

In this study, I investigate student "buy-in", defined as students' proper understanding of and agreement with the class format, for introductory studio physics classes that incorporate lectures, labs, and group problem-solving activities into one interactive environment. I also investigate the ways in which instructors try to gain student buy-in to their class. Research has shown that student resistance to reformed instruction is a barrier to an instructor's use of research-based instructional strategies that are common to the studio class. Expectancy value theory suggests that by gaining student buy-in to the reformed class format, student resistance will decrease thus allowing a …

Go to article

Thin-Film Lithium Niobate Photonics For Electro-Optics, Nonlinear Optics, And Quantum Optics On Silicon, Ashutosh Rao Jan 2018

Thin-Film Lithium Niobate Photonics For Electro-Optics, Nonlinear Optics, And Quantum Optics On Silicon, Ashutosh Rao

Electronic Theses and Dissertations

Ion-sliced thin-film lithium niobate (LN) compact waveguide technology has facilitated the resurgence of integrated photonics based on lithium niobate. These thin-film LN waveguides offer over an order of magnitude improvement in optical confinement, and about two orders of magnitude reduction in waveguide bending radius, compared to conventional LN waveguides. Harnessing the improved confinement, a variety of miniaturized and efficient photonic devices are demonstrated in this work. First, two types of compact electrooptic modulators are presented – microring modulators, and Mach-Zehnder modulators. Next, two distinct approaches to nonlinear optical frequency converters are implemented – periodically poled lithium niobate, and mode shape …

Go to article

Investigating Compositional Variations Of S-Complex Near-Earth Asteroids: (1627) Ivar, Jenna Jones Jan 2018

Investigating Compositional Variations Of S-Complex Near-Earth Asteroids: (1627) Ivar, Jenna Jones

Electronic Theses and Dissertations

We seek to investigate the complexity and heterogeneity of the surfaces of near-Earth asteroids (NEAs). In particular, we are studying the S-complex NEAs, which account for a large portion of the observed near-Earth objects. Here we present our results for (1627) Ivar, an Amor class NEA with taxonomic type Sqw. In 2013, Ivar's large size and close approach to Earth (minimum distance 0.32 AU) provided an opportunity to observe the asteroid over many different viewing angles for an extended period of time. We collected delay-Doppler radar images and Doppler spectra using the Arecibo Observatory's 2380 MHz radar, and, by incorporating …

Go to article

Electronic, Optical, And Magnetic Properties Of Graphene And Single-Layer Transition Metal Dichalcogenides In The Presence Of Defects, Mahtab Khan Jan 2018

Electronic, Optical, And Magnetic Properties Of Graphene And Single-Layer Transition Metal Dichalcogenides In The Presence Of Defects, Mahtab Khan

Electronic Theses and Dissertations

Two-dimensional (2D) materials, such as graphene and single-layer (SL) transition metal dichalcogenides (TMDCs), have attracted a lot of attention due to their fascinating electronic and optical properties. Graphene was the first 2D material that has successfully been exfoliated from bulk graphite in 2004. In graphene, charge carriers interacting with the honeycomb lattice of carbon atoms of graphene to appear as massless Dirac fermions. Massless quasiparticles with linear dispersion are also observed in surface states of 3D topological insulators and quantum Hall edge states. My first project deals with the two-dimensional Hong-Ou-Mandel (HOM) type interference experiment for massless Dirac fermions in …

Go to article

First Prev Next Last