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Structured Light-Field Focusing 3d Density Measurements Of A Supersonic Cone, Ryonosuke Ozawa Jan 2018

Structured Light-Field Focusing 3d Density Measurements Of A Supersonic Cone, Ryonosuke Ozawa

Electronic Theses and Dissertations

This study describes three-dimensional (3D) quantitative visualization of density field in a supersonic flow around a cone spike. A measurement of the density gradient is conducted within a supersonic wind tunnel facility at the Propulsion and Energy Research Laboratory at the University of Central Florida utilizing Structured Light-Field Focusing Schlieren (SLLF). In conventional schlieren and Shadowgraph techniques, it is widely known that a complicated optical system is needed and yet visualizable area depends on an effective diameter of lenses and mirrors. Unlike these techniques, SLLF is yet one of the same family as schlieren photography, it is capable of non-intrusive …

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Generation And Characterization Of Isolated Attosecond Pulse In The Soft X-Ray Regime, Jie Li Jan 2018

Generation And Characterization Of Isolated Attosecond Pulse In The Soft X-Ray Regime, Jie Li

Electronic Theses and Dissertations

The observation of any atomic and molecular dynamics requires a probe that has a timescale comparable to the dynamics itself. Ever since the invention of laser, the temporal duration of the laser pulse has been incrementally reduced from several nanoseconds to just attoseconds. Picosecond and femtosecond laser pulses have been widely used to study molecular rotation and vibration. In 2001, the first single isolated attosecond pulse (1 attosecond = 10^-18 seconds.) was demonstrated. Since this breakthrough, "attoscience" has become a hot topic in ultrafast physics. Attosecond pulses typically have span between EUV to X-ray photon energies and sub-femtosecond pulse duration. …

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Potential Relationship Between Vascular Depression And Autobiographical Memory Specificity In An Older Adult Population According To The Car-Fa-X Model, Manuel Herrera Legon Jan 2018

Potential Relationship Between Vascular Depression And Autobiographical Memory Specificity In An Older Adult Population According To The Car-Fa-X Model, Manuel Herrera Legon

Electronic Theses and Dissertations

Vascular depression is a type of depression that has its onset later in life, and it has been associated with cardiovascular or metabolic diseases. Depression can be costly and associated with other health problems, which is why it becomes imperative to uncover the multiple mechanisms of action for depression symptomatology. A proposed mechanism of action for the emergence of depressive symptomatology is poor autobiographical memory specificity according to the CaR-FA-X model. However, it remains unclear whether this mechanism contributes somehow to the vascular depression specific type. The purpose of this research was to determine the potential relationship between the mechanisms …

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Young Adult Development And Caregiving: Disposition And Involvement In Care, Nicholas James Jan 2018

Young Adult Development And Caregiving: Disposition And Involvement In Care, Nicholas James

Electronic Theses and Dissertations

Caregivers are a diverse group of individuals with a variety of backgrounds and roles; however, research has widely overlooked young adults in this population. This study investigated young adult caregiver circumstance, burden, and use of support services with the purpose of improving future caregiving research and interventions. Study 1 compared burden and circumstance among young, middle aged, and older adult caregivers (N = 285) in addition to developmental indicators among young adults caregiver and demographically matched non-caregiver peers (n = 225). Study 2 surveyed caregivers from each age group (N = 151) on barriers to care, treatment preferences, and interest …

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Working Memory Capacity And Executive Attention As Predictors Of Distracted Driving, Jennifer Louie Jan 2018

Working Memory Capacity And Executive Attention As Predictors Of Distracted Driving, Jennifer Louie

Electronic Theses and Dissertations

The present study empirically examined the effects of working memory capacity (WMC) and executive attention on distracted driving. Study 1 examined whether a Grocery List Task (GLT) distractor would load onto WMC. Forty-three participants completed a series of WMC tasks followed by the GLT. They then completed two driving trials: driving without the GLT and driving while completing the GLT. It was hypothesized that WMC would positively correlate with GLT performance. A bivariate correlation indicated that WMC was positively associated with performance on the GLT. Study 2 tested a series of distractor tasks (GLT, Tone Monitoring, and Stop Signal) to …

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Categorical Change: Exploring The Effects Of Concept Drift In Human Perceptual Category Learning, Andrew Wismer Jan 2018

Categorical Change: Exploring The Effects Of Concept Drift In Human Perceptual Category Learning, Andrew Wismer

Electronic Theses and Dissertations

Categorization is an essential survival skill that we engage in daily. A multitude of behavioral and neuropsychological evidence support the existence of multiple learning systems involved in category learning. COmpetition between Verbal and Implicit Systems (COVIS) theory provides a neuropsychological basis for the existence of an explicit and implicit learning system involved in the learning of category rules. COVIS provides a convincing account of asymptotic performance in human category learning. However, COVIS – and virtually all current theories of category learning – focus solely on categories and decision environments that remain stationary over time. However, our environment is dynamic, and …

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Graphene Induced Formation Of Nanostructures In Composites, Chen Shen Jan 2018

Graphene Induced Formation Of Nanostructures In Composites, Chen Shen

Electronic Theses and Dissertations

Graphene induced nanostructures in graphene-based composites and the performance of these composites have been explored in this study. For the metallic nanoparticles decorated graphene aerogels composites, the fabrication of hierarchically structured, reduced graphene oxide (rGO) aerogels with heavily metallic nanoparticles was realized. Higher loading of palladium nanoparticles in graphene aerogels leads to improved hydrogen gas sensing performance. For polymer derived ceramics (PDCs) composites with anisotropic electrical properties, the fabrication of composites was realized by embedding anisotropic reduced graphene oxide aerogels (rGOAs) into the PDCs matrix. Raman spectroscopy and X-ray diffraction studies of PDCs composites with and without graphene indicate that …

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Towards High-Performance Big Data Processing Systems, Hong Zhang Jan 2018

Towards High-Performance Big Data Processing Systems, Hong Zhang

Electronic Theses and Dissertations

The amount of generated and stored data has been growing rapidly, It is estimated that 2.5 quintillion bytes of data are generated every day, and 90% of the data in the world today has been created in the last two years. How to solve these big data issues has become a hot topic in both industry and academia. Due to the complex of big data platform, we stratify it into four layers: storage layer, resource management layer, computing layer, and methodology layer. This dissertation proposes brand-new approaches to address the performance of big data platforms like Hadoop and Spark on …

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Assessment Of Information Security Culture In Higher Education, Henry Glaspie Jan 2018

Assessment Of Information Security Culture In Higher Education, Henry Glaspie

Electronic Theses and Dissertations

Information security programs are instituted by organizations to provide guidance to their users who handle their data and systems. The main goal of these programs is to protect the organization's information assets through the creation and cultivation of a positive information security culture within the organization. As the collection and use of data expands in all economic sectors, the threat of data breach due to human error increases. Employee's behavior towards information security is influenced by the organizations information security programs and the overall information security culture. This study examines the human factors of an information security program and their …

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Unearthing The Past And Present Of A Semi-Fossorial Lizard: Conservation Genetics, Phylogeography, And Taxonomy Of Plestiodon Egregius., Kathryn Mercier Jan 2018

Unearthing The Past And Present Of A Semi-Fossorial Lizard: Conservation Genetics, Phylogeography, And Taxonomy Of Plestiodon Egregius., Kathryn Mercier

Electronic Theses and Dissertations

Characterizing an organism's evolutionary history and population structure as well as understanding the forces shaping that divergence is crucial to conservation biology. A clear understanding of the patterns of diversity and divergence are imperative for the best management of the organism, while an awareness of what drives these patterns can lead to better predictions of how organisms will respond to future climate change. Historical climate changes and associated sea level change are among the main forces driving divergence in many species. To examine how effects of climate changes may have driven patterns of intraspecific divergence, I examined Mole Skinks, Plestiodon …

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Destination Image And Tourist's Imagination: The Forgotten Component, Jalayer Khalilzadeh Jan 2018

Destination Image And Tourist's Imagination: The Forgotten Component, Jalayer Khalilzadeh

Electronic Theses and Dissertations

The objectives of this dissertation was to 1) develop a comprehensive scale to measure visitors' imagination, 2) investigate the structural relationship between imagination and tourism destination image (TDI) components of cognitive, affective, and conative, 3) compare and contrast the various qualities of vividness, richness, saliency, control, and spatial between imagination and prospection, and 4) study the impact of different information sources on the evolving process of prospection to imagination. By conducting four different studies and seven data collection phases, the imagination scale was developed, validated, and utilized to test the proposed structural and differential hypotheses. In study 1, the phenomenology …

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Identifying Type Of Expertise As A Means To Measure Crm Knowledge Structures, Camilo Jimenez Jan 2018

Identifying Type Of Expertise As A Means To Measure Crm Knowledge Structures, Camilo Jimenez

Electronic Theses and Dissertations

Crew Resource Management (CRM) training has evolved since its inception in the 1980s to better accommodate the operational needs of flight crews. However, even as the aviation and research communities have pointed to the potential benefit of providing CRM training, some criticism continues to emerge periodically which claims that there is no concrete evidence of its impact on flight deck performance and safety. Therefore, it is imperative to develop tools that allow researchers and, more importantly, practitioners, to more effectively and objectively assess training effectiveness and identify whether or not desired CRM behaviors are being put to practice during line …

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Effect Of Nonclassical Optical Turbulence On A Propagating Laser Beam, Melissa Beason Jan 2018

Effect Of Nonclassical Optical Turbulence On A Propagating Laser Beam, Melissa Beason

Electronic Theses and Dissertations

Theory developed for the propagation of a laser beam through optical turbulence generally assumes that the turbulence is both homogeneous and isotropic and that the associated spectrum follows the classical Kolmogorov spectral power law of κ-11/3. If the atmosphere deviates from these assumptions, beam statistics such as mean intensity, correlation, and scintillation index could vary significantly from mathematical predictions. This work considers the effect of nonclassical turbulence on a propagated beam. Namely, anisotropy of the turbulence and a power law that deviates from κ-11/3. A mathematical model is developed for the scintillation index of a Gaussian beam propagated through nonclassical …

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Assessment Of Microstructure And Mechanical Behavior Of Materials And Phases Observed In Low-Enriched Uranium Monolithic Fuel Plates After Fabrication, Ryan Newell Jan 2018

Assessment Of Microstructure And Mechanical Behavior Of Materials And Phases Observed In Low-Enriched Uranium Monolithic Fuel Plates After Fabrication, Ryan Newell

Electronic Theses and Dissertations

Low enriched uranium (LEU) fuels are being developed to reduce the use of highly enriched uranium in power generation to reduce proliferation risks. Challenges arise in providing sufficient fissile U in LEU without reactor redesign. As such, a novel monolithic fuel plate design employs LEU alloyed with 10 wt. % Mo. Throughout fabrication of these fuel plates, metallurgical transformations and reactions take place as a result of elevated temperatures during processing. The transformations include decomposition of the metastable body-centered cubic γ phase in the fuel and metallurgical interactions at interfaces between fuel plate components. This work aims to provide further …

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The African Puzzle: A Study Of Democratic Backsliding In Sub Saharan Africa, Ailbhe Rice Jan 2018

The African Puzzle: A Study Of Democratic Backsliding In Sub Saharan Africa, Ailbhe Rice

Electronic Theses and Dissertations

The following study examines the future of democratization and the apparent trend towards autocratization within the context of democratic backsliding in Sub-Saharan Africa. Initially, the findings indicate that regionally, backsliding is not acting fundamentally different in Sub-Saharan Africa when compared to other regions. The analysis finds that regime duration and civil conflict are both significant when it comes to the study of democratic backsliding. The variable for the prior military regime's is extremely significant in all of the models and is, therefore, a strong indicator of backsliding in Africa. The chief takeaway from the study is in the variable for …

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Probing The Effects Of Substrate Stiffness On Astrocytes Mechanics, Ariege Bizanti Jan 2018

Probing The Effects Of Substrate Stiffness On Astrocytes Mechanics, Ariege Bizanti

Electronic Theses and Dissertations

Astrocytes are among the most functionally diverse population of cells in the central nervous system (CNS) as they are essential to many important neurological functions including maintaining brain homeostasis, regulating the blood brain barrier, and preventing build-up of toxic substances within the brain, for example. Astrocyte importance to brain physiology and pathology has inspired a host of studies focused on understanding astrocyte behavior primarily from a biological and chemical perspective. However, a clear understanding of astrocyte dysfunction and their link to disease has been hampered by a lack of knowledge of astrocyte behavior from a biomechanical perspective. Furthermore, astrocytes (and …

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The Effect Of Martensite-Fractions Assumptions In Shape Memory Alloy Springs, Christian Vazquez Jan 2018

The Effect Of Martensite-Fractions Assumptions In Shape Memory Alloy Springs, Christian Vazquez

Electronic Theses and Dissertations

This research addresses various models of a spring-mass system that uses a spring made of a shape memory alloy (SMA). The system model describes the martensite fractions, which are values that describe an SMA's crystalline phases, via differential equations. The model admits and this thesis contrasts two commonly used but distinct assumptions: a homogeneous case where the martensite fractions are constant throughout the spring's cross section, and a bilinear case where the evolution of the martensite fractions only occurs beyond some critical radius. While previous literature has developed a model of the system dynamics under the homogeneous assumption using the …

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Catalyst Design And Mechanism Study With Computational Method For Small Molecule Activation, Muqiong Liu Jan 2018

Catalyst Design And Mechanism Study With Computational Method For Small Molecule Activation, Muqiong Liu

Electronic Theses and Dissertations

Computational chemistry is a branch of modern chemistry that utilizes the computers to solve chemical problems. The fundamental of computational chemistry is Schrödinger equation. To solve the equation, researchers developed many methods based on BornOppenheimer Approximation, such as Hartree-Fock method and DFT method, etc. Computational chemistry is now widely used on reaction mechanism study and new chemical designing. In the first project described in Chapter 3, we designed phosphine oxide modified Ag3, Au3 and Cu3 nanocluster catalysts with DFT method. We found that these catalysts were able to catalyze the activation of H2 by cleaving the H-H bond asymmetrically. The …

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Evaluating The Interaction Between The Human Melanocortin-2 Receptor And The Accessory Protein, Mrap1: Chimeric Receptor And Alanine Substitution Studies On Transmembrane Domain 4, Extracellular Loop 2, And Transmembrane Domain 5, Perry Victoria Davis Jan 2018

Evaluating The Interaction Between The Human Melanocortin-2 Receptor And The Accessory Protein, Mrap1: Chimeric Receptor And Alanine Substitution Studies On Transmembrane Domain 4, Extracellular Loop 2, And Transmembrane Domain 5, Perry Victoria Davis

Electronic Theses and Dissertations

The melanocortin-2 receptor (MC2R) is the most complex due to its trafficking and ligand selectivity requirements for proper activation. The MC2R requires the melanocortin receptor accessory protein-1 (MRAP1) for proper trafficking and activation of the receptor by the melanocortin hormone, ACTH. MRAP1 is a single transmembrane-spanning domain protein that creates a homodimer with another MRAP1 protein. Furthermore, MRAP2 creates a heterodimer with the MC2R. Previous studies have shown that the MRAP1 protein contains an activation motif required for activation of MC2R and this activation motif located on the extracellular space side of the plasma membrane of the cell. The objective …

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A Review Of The Serica (Coleoptera: Scarabaeidae: Melolonthinae) Of Mexico, Canada, And The Western United States, Reese John Worthington Jan 2018

A Review Of The Serica (Coleoptera: Scarabaeidae: Melolonthinae) Of Mexico, Canada, And The Western United States, Reese John Worthington

Electronic Theses and Dissertations

Twenty-two species and subspecies of Serica occur in Mexico. Serica ensenada Saylor, 1948 is recognized as a junior synonym of Serica pilifera Horn, 1894. Two new species, Serica ascia Lago & Worthington and Serica fenestra Lago & Worthington are described from Mexico. Three genera of Sericini are recorded from Canada, Maladera castanea (Arrow), Nipponoserica peregrina (Chapin), and twelve species of Serica. Seventy-seven species and subspecies of Serica occur in the contiguous United States west of the 100th meridian. Eleven new species, Serica berriani Lago & Worthington, Serica cuneiverpa Lago & Worthington, Serica desolaterra Lago & Worthington, Serica katelinae Lago & …

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Examining Changes In Bat Swing Kinematics In Various Regions Of The Strike Zone In Collegiate Baseball And Softball Players, Caleb Williams Jan 2018

Examining Changes In Bat Swing Kinematics In Various Regions Of The Strike Zone In Collegiate Baseball And Softball Players, Caleb Williams

Electronic Theses and Dissertations

According to the National Collegiate Athletic Association (NCAA) there are over 50,000 men and women who compete in collegiate baseball and softball. These individuals spend hours improving their ability to swing a bat with the hope of improving his or her batting performance during a game situation typically off a tee in a position of their own choosing. However, during a game situation an athlete may swing a bat through his or her strike zone depending upon the pitch thrown by an opposing pitcher. The strike zone is defined as the space over home plate in a region that is …

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The Identification And Segmentation Of Astrocytoma Prior To Critical Mass, By Means Of A Volumetric/Subregion Regression Analysis Of Normal And Neoplastic Brain Tissue, Lyn Higgins Jan 2018

The Identification And Segmentation Of Astrocytoma Prior To Critical Mass, By Means Of A Volumetric/Subregion Regression Analysis Of Normal And Neoplastic Brain Tissue, Lyn Higgins

Electronic Theses and Dissertations

As the underlying cause of Glioblastoma Multiforme (GBM) is presently unclear, this research implements a new approach to identifying and segmenting plausible instances of GBM prior to critical mass. Grade-IV Astrocytoma, or GBM, is an aggressive and malignant cancer arising from star-shaped glial cells, or astrocytes, where the astrocytes, functionally, assist in the support and protection of neurons within the central nervous system and spinal cord. Subsequently, our motivation for researching the ability to recognize GBM is that the underlying cause of the mutation is presently unclear, leading to the operative that GBM is only detectable through a combination of …

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Oculomotor Mechanisms Underlying Attentional Costs In Distracted Visual Search, Joanna Lewis Jan 2018

Oculomotor Mechanisms Underlying Attentional Costs In Distracted Visual Search, Joanna Lewis

Electronic Theses and Dissertations

Performance consequences have been long established when humans multitask. This research concerns the impact of distraction on the attentional shifts during a task that underlies many cognitive processes and everyday tasks, searching for a target item among non-target items (e.g., scanning the road for potential collisions). There is evidence that increasing the mental workload by introducing additional tasks influences our ability to search our environment or interferes with processing fixated information. In the current studies, I aimed to evaluate the changes in gaze behaviors during visual search to evaluate how multitasking impairs our attentional processes. Participants completed a visual search …

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Different Facial Recognition Techniques In Transform Domains, Taif Al Obaidi Jan 2018

Different Facial Recognition Techniques In Transform Domains, Taif Al Obaidi

Electronic Theses and Dissertations

The human face is frequently used as the biometric signal presented to a machine for identification purposes. Several challenges are encountered while designing face identification systems. The challenges are either caused by the process of capturing the face image itself, or occur while processing the face poses. Since the face image not only contains the face, this adds to the data dimensionality, and thus degrades the performance of the recognition system. Face Recognition (FR) has been a major signal processing topic of interest in the last few decades. Most common applications of the FR include, forensics, access authorization to facilities, …

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Pressure Image Based Attitude Controller For Small Unmanned Aerial Vehicles, Kenneth Thompson Jan 2018

Pressure Image Based Attitude Controller For Small Unmanned Aerial Vehicles, Kenneth Thompson

Electronic Theses and Dissertations

As technology improves, small unmanned aerial vehicles (SUAV) have been identified for their utility in a variety of applications in which larger unmanned craft may be incapable of accomplishing mission objectives. These aircraft with their small size and long flight durations are ideal for hazardous inspection and long duration surveillance missions. One challenge preventing the widespread adoption of these systems is their instability to abrupt changes in the flow field around them due to wind gusts or flow separation. Currently, traditional rigid body based sensors are implemented in their flight control systems, which are sufficient in higher inertia aircraft for …

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The Resonance And Residue Of The First African American Newspaper: How Freedom's Journal Created Space In The Early 19th Century, Valerie Kasper Jan 2018

The Resonance And Residue Of The First African American Newspaper: How Freedom's Journal Created Space In The Early 19th Century, Valerie Kasper

Electronic Theses and Dissertations

The first African American newspaper, Freedom's Journal, has a historical, rhetorical, and spatial purpose. It not only showed the impact made by African Americans in the fight for their civil rights in the early 19th century, but as an artifact it illustrated and preserved that history allowing it to be studied centuries after the newspaper ceased printing. The purpose of The Resonance and Residue of the First African American Newspaper: How Freedom's Journal Created Space in the Early 19th Century is to provide an interdisciplinary approach to historical newspapers that illustrates an alternative history in this country — a history …

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Digital Citizenship Tools For Cause-Based Campaigns: A Broadened Spectrum Of Social Media Engagement And Participation-Scale Methodology, Jennifer Miller Jan 2018

Digital Citizenship Tools For Cause-Based Campaigns: A Broadened Spectrum Of Social Media Engagement And Participation-Scale Methodology, Jennifer Miller

Electronic Theses and Dissertations

Digital Citizenship Tools for Cause-Based Campaigns: A Broadened Spectrum of Social Media Engagement and Participation-Scale Methodology develops and applies two new tools for understanding, measuring, and recursively adjusting small to medium-size social media-based philanthropic campaigns to better foster participation and engagement—in other words, democratic digital citizenship. First, a theoretical model is offered broadening current binary conceptions of success and failure or impact of campaigns, situating specific participant actions in social media on a spectrum. Then, from that model, a new methodology is provided to measure participation and engagement generated by campaign posts. Recommendations are also offered for recursively adjusting campaign …

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Emergent Narrative: Stories Of Play, Playing With Stories, Eric Murnane Jan 2018

Emergent Narrative: Stories Of Play, Playing With Stories, Eric Murnane

Electronic Theses and Dissertations

Emergent narrative, a phenomenon of unexpected contextual stories arising through play, has been researched in the field of game studies since 1999. However, that discussion largely lies in the realm of theoretical stories which are generated by either the system or the player. The purpose of this dissertation is to deepen our understanding of emergent narrative by examining real-world examples of the phenomenon. Four hundred player posts were gathered from forums relating to the video game Skyrim (a large, open world fantasy roleplaying game) and analyzed using a mixed-method framework which is informed by digital ethnography, fan studies, and game …

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Visionary Ophthalmics: Confluence Of Computer Vision And Deep Learning For Ophthalmology, Dustin Morley Jan 2018

Visionary Ophthalmics: Confluence Of Computer Vision And Deep Learning For Ophthalmology, Dustin Morley

Electronic Theses and Dissertations

Ophthalmology is a medical field ripe with opportunities for meaningful application of computer vision algorithms. The field utilizes data from multiple disparate imaging techniques, ranging from conventional cameras to tomography, comprising a diverse set of computer vision challenges. Computer vision has a rich history of techniques that can adequately meet many of these challenges. However, the field has undergone something of a revolution in recent times as deep learning techniques have sprung into the forefront following advances in GPU hardware. This development raises important questions regarding how to best leverage insights from both modern deep learning approaches and more classical …

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Categorical Range Reporting In 2d Using Wavelet Tree, Swathi Kanthareddy Sumithra Jan 2018

Categorical Range Reporting In 2d Using Wavelet Tree, Swathi Kanthareddy Sumithra

Electronic Theses and Dissertations

The research involved optimizing the space and bounding the output time by the output size in categorical range reporting of points within the given rectangle query Q in two dimension using wavelet trees and range counting. The time taken to report those points and space to tore n points in set S can be done using wavelet tree and range counting. Consider set S consisting of n points in two-dimension. An orthogonal range reporting query rectangle Q = [a,b] x [c,d] on set S is sent to report the set of points in S which interacts with the query rectangle[Q]. …

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