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Articles 511 - 540 of 2906

Full-Text Articles in Physical Sciences and Mathematics

Cancerous Male And Female Gene Expression, Clarissa Farmer, E. Shannon Tass Jun 2019

Cancerous Male And Female Gene Expression, Clarissa Farmer, E. Shannon Tass

Journal of Undergraduate Research

Genetic diagnosing is becoming more popular, as well as more and more accurate. However, many genetic diseases have complex genetic effects and are still not fully understood. Transthyretin Amyloidosis (ATTR; also known as familial or hereditary amyloidosis) is a terminal genetic disease. It is caused by unstable transthyretin proteins that fold improperly, and then deteriorate. The fragmented proteins are deposited outside of the cell and build up in the tissues over time, forming insoluble oligomers. The oligomers continue to grow into Amyloid fibrils, which adversely affect many organs in the body, eventually causing their failure. In order to accurately diagnose, …

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Cyclic Peptide Catalyst Design, Millicent Campbell, David Michaelis Jun 2019

Cyclic Peptide Catalyst Design, Millicent Campbell, David Michaelis

Journal of Undergraduate Research

Enzymes found in nature are more efficient catalysts than those used in organic chemistry labs. However, natural enzymes are not ideal for organic synthesis because they only make one product and only work in specific conditions. The Michaelis lab designed a catalyst capable of mimicking enzyme-like reactivity in the lab. This catalyst consists of an alpha helix with an imidazolidinone catalyst and a thiourea catalyst (see figure 1). The imidazolidinone catalyst and thiourea catalysts are attached adjacent to each other on the alpha helix, which acts as a rigid scaffold that can mimic the proximity effects seen in natural enzymes. …

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Heterodinuclear Co-Zr Compound Shows Increased Reactivity In Kumada Coupling, James Coombs, Daniel Ess Jun 2019

Heterodinuclear Co-Zr Compound Shows Increased Reactivity In Kumada Coupling, James Coombs, Daniel Ess

Journal of Undergraduate Research

Heterodinuclear compounds containing a metal–metal bond represent a potentially useful subclass of catalyst in organic synthesis. Heterodinuclear compounds offer the possibility of increased reactivity due to interactions between metal centers (Scheme 1A). These so-called cooperative effects can enhance reactivity by changing the electronic density, increasing nucleophilicity/electrophilicity of the reactive metal, and by lowering the energy barriers for changes in oxidation state. These changes in reactivity can allow a heterodinuclear compound to be an effective catalyst for many chemical reactions that would be unfeasible with a mononuclear analogue.

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Detecting Microcracks In Structures By Electromagnetic Excitation Of Acoustic Resonances, Joshua Gregg, Brian Anderson Jun 2019

Detecting Microcracks In Structures By Electromagnetic Excitation Of Acoustic Resonances, Joshua Gregg, Brian Anderson

Journal of Undergraduate Research

Stainless steel structures are often affected by stress corrosion cracking, which makes microscopic cracks that can go unnoticed and eventually cause the structure to fail. A useful method for detecting stress corrosion cracking is nonlinear resonant ultrasound spectroscopy (NRUS). NRUS involves vibrating a sample and looking for amplitude-dependent shifts in the sample’s resonance frequencies. NRUS tests are typically performed by driving vibrations in rods with piezoelectric transducers and measuring the amplitude-dependent shifts in the resonance frequencies. I am developing a different technique for driving the vibrations, which has never been used for NRUS. The technique uses a coil attached to …

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Primordial Origins Of Supermassive Black Holes, William Black, David Neilson Jun 2019

Primordial Origins Of Supermassive Black Holes, William Black, David Neilson

Journal of Undergraduate Research

At the center of the Milky Way sits a supermassive black hole named Sagittarius A*1, which is over a million times the mass of our sun. Other galaxy centers host similar black holes which are up to thousands of times larger than even Sagittarius A*. Some of these giants have been sighted in the very early universe (700 million years after the Big Bang is still relatively early in the universe—it’s now been nearly 14 billion years!).

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Increasing Cryptographic Security Through Quantum Erasure, Richard Barney, Jean-Françios S. Van Huele Jun 2019

Increasing Cryptographic Security Through Quantum Erasure, Richard Barney, Jean-Françios S. Van Huele

Journal of Undergraduate Research

In our increasingly data-driven society, the ability to transmit secure messages is more essential than ever. This ability allows economies to thrive and protects both personal and national security. In order to achieve this security, cryptographers have developed methods to encrypt data. One of the most successful of these methods is to use a secure key to encrypt and decrypt the sensitive data. This method has been very successful but it is still possible for outside agents to obtain the secure key and thereby access sensitive information.

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Geological And Geochemical Controls On Non-Tuberculous Mycobacterium Transmission: Examples From Hawaii, Schuyler Thomas Robinson Jun 2019

Geological And Geochemical Controls On Non-Tuberculous Mycobacterium Transmission: Examples From Hawaii, Schuyler Thomas Robinson

Theses and Dissertations

The opportunistic environmental microbes, non-tuberculous Mycobacterium (NTM), pose an increasing risk of disease and death in both immunodeficient and immunocompetent individuals in the USA and across the world. NTM lung disease is particularly prevalent in Hawaii, although the modes of NTM acquisition and transport in Hawaii are not fully understood. This study evaluated 149 soil and 50 water samples across the Hawaiian Islands to determine geochemical factors controlling NTM. Non-metric multidimensional scaling (NMDS) and principal component analyses (PCA) of modern soils show variables such as Total Organic Carbon (TOC), pH, P, mafic silicate minerals, and Pb seem to control NTM …

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Basinward Trends In Fluvial Architecture, Connectivity, And Reservoir Characterization Of The Trail Member, Ericson Sandstone, Mesaverde Group In Wyoming, Utah, And Colorado, Usa, Chelsea Anne Jolley Jun 2019

Basinward Trends In Fluvial Architecture, Connectivity, And Reservoir Characterization Of The Trail Member, Ericson Sandstone, Mesaverde Group In Wyoming, Utah, And Colorado, Usa, Chelsea Anne Jolley

Theses and Dissertations

The Late Cretaceous Trail Member of the Ericson Sandstone represents a regionally extensive fluvial system that transported sediments from the Sevier fold and thrust belt and Uinta Mountain uplift to the Western Interior Seaway. The Trail Member is a petroleum reservoir target that has unpredictable production rates due to the unknown behavior and connectivity of channel sandstones. The abundant outcrop, wellbore, and core data available allows for a comprehensive analysis of how the fluvial architecture, connectivity, and reservoir quality change along 65 km of depositional dip. Observations made at Flaming Gorge and Clay Basin (most landward field locations) suggest a …

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Multi-Human Management Of A Hub-Based Colony: Efficiency And Robustness In The Cooperative Best M-Of-N Task, John Rolfes Grosh Jun 2019

Multi-Human Management Of A Hub-Based Colony: Efficiency And Robustness In The Cooperative Best M-Of-N Task, John Rolfes Grosh

Theses and Dissertations

Swarm robotics is an emerging field that is expected to provide robust solutions to spatially distributed problems. Human operators will often be required to guide a swarm in the fulfillment of a mission. Occasionally, large tasks may require multiple spatial swarms to cooperate in their completion. We hypothesize that when latency, bandwidth, operator dropout, and communication noise are significant factors, human organizations that promote individual initiative perform more effectively and resiliently than hierarchies in the cooperative best-m-of-n task. Simulations automating the behavior of hub-based swarm robotic agents and groups of human operators are used to evaluate this hypothesis. To make …

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Secondary Preservice Mathematics Teachers' Curricular Reasoning, Kimber Anne Mathis Jun 2019

Secondary Preservice Mathematics Teachers' Curricular Reasoning, Kimber Anne Mathis

Theses and Dissertations

Researchers have found that teachers' decisions affect students' opportunity to learn. Prior researchers have investigated teachers' decisions while planning, implementing, or reflecting on lessons, but few researchers have studied teachers' decisions and their reasoning throughout the teaching process. It is important to study teachers' reasoning for why they make the decisions they do throughout the teaching process. Furthermore, because inservice and preservice teachers differ in experience and available resources that they draw on while making decisions, it is helpful to consider the resources PSTs' draw on while reasoning. Curricular reasoning is a framework that describes teachers' thinking processes when making …

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Computational Design And Analysis Of Molecular Ethylene Oligomerization Catalysts, Doo Hyun Kwon Jun 2019

Computational Design And Analysis Of Molecular Ethylene Oligomerization Catalysts, Doo Hyun Kwon

Theses and Dissertations

Linear alpha olefins (LAOs) are key petrochemical precursors for the synthesis of larger polymers, detergents, plasticizers, and lubricants. Most catalytic ethylene oligomerization processes generate a wide distribution of LAO carbon chain lengths. A major ongoing industrial challenge is to develop homogeneous catalysts that result in selective and tunable ethylene oligomerization to 1-hexene and 1-octene alkenes. Quantum mechanical calculations coupled with rapidly advancing technology have enabled the ability to calculate small molecule systems with high accuracy. Employing computational models to advance from empirical to quantitative prediction of product selectivities has become an active area of exploration. In this work, we demonstrate …

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Mirror Symmetry For Non-Abelian Landau-Ginzburg Models, Matthew Michael Williams Jun 2019

Mirror Symmetry For Non-Abelian Landau-Ginzburg Models, Matthew Michael Williams

Theses and Dissertations

We consider Landau-Ginzburg models stemming from non-abelian groups comprised of non-diagonal symmetries, and we describe a rule for the mirror LG model. In particular, we present the non-abelian dual group G*, which serves as the appropriate choice of group for the mirror LG model. We also describe an explicit mirror map between the A-model and the B-model state spaces for two examples. Further, we prove that this mirror map is an isomorphism between the untwisted broad sectors and the narrow diagonal sectors in general.

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Mechanically Scanned Interference Pattern Structured Illumination Imaging, Jarom Silver Jackson Jun 2019

Mechanically Scanned Interference Pattern Structured Illumination Imaging, Jarom Silver Jackson

Theses and Dissertations

A method of lensless, single pixel imaging is presented. This method, referred to as MAS-IPSII, is theoretically capable of resolutions as small as one quarter of the wavelength of the imaging light. The resolution is not limited by the aperture of any optic, making high resolutions (including subwavelength) feasible even at very large (greater than a meter) distances. Imaging requires only flat optics and a coherent source, making it a good candidate for imaging with extreme wavelengths in the UV and x-ray regimes. The method is demonstrated by the imaging of various test targets. Both real and complex imaging (i.e. …

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Analytical Expressions For Acoustic Radiation Modes Of Simple Curved Structures, Caleb Burley Goates Jun 2019

Analytical Expressions For Acoustic Radiation Modes Of Simple Curved Structures, Caleb Burley Goates

Theses and Dissertations

The search for a convenient connection between vibration patterns on a structure and the sound radiated from that structure is ongoing in structural acoustics literature. Common techniques are wavenumber domain methods, or representation of the vibration in terms of some basis, such as structural modes or elementary radiators, and calculating the sound radiation in terms of the basis. Most choices for a basis in this situation exhibit strong coupling between the basis functions, but there is one choice which does not: Acoustic radiation modes are by definition the basis that orthogonalizes the radiation operator, meaning the radiation modes do not …

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Deep Synthetic Noise Generation For Rgb-D Data Augmentation, Patrick Douglas Hammond Jun 2019

Deep Synthetic Noise Generation For Rgb-D Data Augmentation, Patrick Douglas Hammond

Theses and Dissertations

Considerable effort has been devoted to finding reliable methods of correcting noisy RGB-D images captured with unreliable depth-sensing technologies. Supervised neural networks have been shown to be capable of RGB-D image correction, but require copious amounts of carefully-corrected ground-truth data to train effectively. Data collection is laborious and time-intensive, especially for large datasets, and generation of ground-truth training data tends to be subject to human error. It might be possible to train an effective method on a relatively smaller dataset using synthetically damaged depth-data as input to the network, but this requires some understanding of the latent noise distribution of …

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Video Prediction With Invertible Linear Embeddings, Robert Thomas Pottorff Jun 2019

Video Prediction With Invertible Linear Embeddings, Robert Thomas Pottorff

Theses and Dissertations

Using recently popularized invertible neural network We predict future video frames from complex dynamic scenes. Our invertible linear embedding (ILE) demonstrates successful learning, prediction and latent state inference. In contrast to other approaches, ILE does not use any explicit reconstruction loss or simplistic pixel-space assumptions. Instead, it leverages invertibility to optimize the likelihood of image sequences exactly, albeit indirectly.Experiments and comparisons against state of the art methods over synthetic and natural image sequences demonstrate the robustness of our approach, and a discussion of future work explores the opportunities our method might provide to other fields in which the accurate analysis …

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Necessary And Sufficient Conditions On State Transformations That Preserve The Causal Structure Of Lti Dynamical Networks, Chi Ho Leung May 2019

Necessary And Sufficient Conditions On State Transformations That Preserve The Causal Structure Of Lti Dynamical Networks, Chi Ho Leung

Theses and Dissertations

Linear time-invariant (LTI) dynamic networks are described by their dynamical structure function, and generally, they have many possible state space realizations. This work characterizes the necessary and sufficient conditions on a state transformation that preserves the dynamical structure function, thereby generating the entire set of realizations of a given order for a specific dynamic network.

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Necessary And Sufficient Conditions On State Transformations That Preserve The Causal Structure Of Lti Dynamical Networks, Chi Ho Leung May 2019

Necessary And Sufficient Conditions On State Transformations That Preserve The Causal Structure Of Lti Dynamical Networks, Chi Ho Leung

Theses and Dissertations

Linear time-invariant (LTI) dynamic networks are described by their dynamical structure function, and generally, they have many possible state space realizations. This work characterizes the necessary and sufficient conditions on a state transformation that preserves the dynamical structure function, thereby generating the entire set of realizations of a given order for a specific dynamic network.

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Necessary And Sufficient Conditions On State Transformations That Preserve The Causal Structure Of Lti Dynamical Networks, Chi Ho Leung May 2019

Necessary And Sufficient Conditions On State Transformations That Preserve The Causal Structure Of Lti Dynamical Networks, Chi Ho Leung

Theses and Dissertations

Linear time-invariant (LTI) dynamic networks are described by their dynamical structure function, and generally, they have many possible state space realizations. This work characterizes the necessary and sufficient conditions on a state transformation that preserves the dynamical structure function, thereby generating the entire set of realizations of a given order for a specific dynamic network.

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Noise Control Of Vacuum-Assisted Toilets, Michael Thomas Rose Apr 2019

Noise Control Of Vacuum-Assisted Toilets, Michael Thomas Rose

Theses and Dissertations

Vacuum-assisted toilets make use of a large pressure difference between the ambient pressure and a vacuum tank to transport waste from the toilet bowl to the septic tank. This process requires 98% less water per flush making it an attractive product for transport vehicles such as airplanes, cruise ships, and trains. Unfortunately, the water savings come at the cost of high noise levels. This thesis investigates the acoustic characteristics of a vacuum-assisted toilet flush and several methods to reduce the radiated noise. Some methods include changing rinse parameters such as rinse pressure, rinse length, and rinse timing, adding structural damping …

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Design And Synthesis Of Ceragenins–Cationic Steroid Antimicrobial Compounds, Structural Improvement And Synthesis Of Cyclopentenone Prostaglandins And Modification And Synthesis Of Derivatives Of Ribityllumazines: Potential Antigens For Activation Of Mait Cells, Yubo Li Apr 2019

Design And Synthesis Of Ceragenins–Cationic Steroid Antimicrobial Compounds, Structural Improvement And Synthesis Of Cyclopentenone Prostaglandins And Modification And Synthesis Of Derivatives Of Ribityllumazines: Potential Antigens For Activation Of Mait Cells, Yubo Li

Theses and Dissertations

Antimicrobial peptides (AMPs) are ubiquitous and display broad-spectrum antimicrobial activity that can control bacterial colonization of surfaces. Ceragenins are small-molecule mimics of AMPs and have several advantages over AMPs, including cost of manufacture and stability. A ceragenin, CSA-120, modified with an acrylamide group was directly incorporated into fluoropolymer coatings as a means of inhibiting bacterial biofilm formation. The ceragenin-containing coatings displayed improved performance. By conjugating a copper chelating group to the ceragenin, chelation of 64Cu by the conjugate was effective and provided a stable complex that allowed in vivo imaging. This conjugate may provide a means of identifying infection sites …

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Representation And Reconstruction Of Linear, Time-Invariant Networks, Nathan Scott Woodbury Apr 2019

Representation And Reconstruction Of Linear, Time-Invariant Networks, Nathan Scott Woodbury

Theses and Dissertations

Network reconstruction is the process of recovering a unique structured representation of some dynamic system using input-output data and some additional knowledge about the structure of the system. Many network reconstruction algorithms have been proposed in recent years, most dealing with the reconstruction of strictly proper networks (i.e., networks that require delays in all dynamics between measured variables). However, no reconstruction technique presently exists capable of recovering both the structure and dynamics of networks where links are proper (delays in dynamics are not required) and not necessarily strictly proper.The ultimate objective of this dissertation is to develop algorithms capable of …

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Deciphering The Transport Of Elastic Filaments By Antagonistic Motor Proteins, Stephanie Portet, Cecil Leduc, Sandrine Etienne-Manneville, J. C. Dallon Apr 2019

Deciphering The Transport Of Elastic Filaments By Antagonistic Motor Proteins, Stephanie Portet, Cecil Leduc, Sandrine Etienne-Manneville, J. C. Dallon

Faculty Publications

Intermediate filaments are long elastic fibres that are transported by microtubule-associated motor proteins kinesin and dynein inside the cell. How elastic filaments are efficiently transported by antagonistic motors is not well understood and difficult to measure with current experimental techniques. Adapting the tug-of-war paradigm for vesicle-like cargos, we develop a mathematical model to describe the motion of an elastic filament punctually bound to antagonistic motors. As observed in cells, up to 3 modes of transport are obtained; dynein-driven retrograde, kinesin-driven anterograde fast motions and a slow motion. Motor properties and initial conditions that depend on intracellular context, regulate the transport …

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Hot Springs Inflow Controlled By The Damage Zone Of A Major Normal Fault, Steven Benjamin Godwin Apr 2019

Hot Springs Inflow Controlled By The Damage Zone Of A Major Normal Fault, Steven Benjamin Godwin

Theses and Dissertations

Spring water inflow is distinct at Pah Tempe Hot Springs (also known as Dixie Hot Springs) situated within the damage zone of the Hurricane Fault in Timpoweap Canyon in Hurricane, Utah. Excising of the footwall by the Virgin River has created Timpoweap Canyon and allowed an unusual opportunity to study the spring inflow in relation to the fault damage zone. While correlation of these springs with the damage zone and visible fracture patterns on the canyon wall has been made, no subsurface faulting has been imaged to verify connection to these visible fractures and spring inflows (Nelson et al., 2009). …

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Regular Fibrations Over The Hawaiian Earring, Stewart Mason Mcginnis Apr 2019

Regular Fibrations Over The Hawaiian Earring, Stewart Mason Mcginnis

Theses and Dissertations

We present a family of fibrations over the Hawaiian earring that are inverse limits of regular covering spaces over the Hawaiian earring. These fibrations satisfy unique path lifting, and as such serve as a good extension of covering space theory in the case of nonsemi-locally simply connected spaces. We give a condition for when these fibrations are path-connected.

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Exponential Stability Of Intrinsically Stable Dynamical Networks And Switched Networks With Time-Varying Time Delays, David Patrick Reber Apr 2019

Exponential Stability Of Intrinsically Stable Dynamical Networks And Switched Networks With Time-Varying Time Delays, David Patrick Reber

Theses and Dissertations

Dynamic processes on real-world networks are time-delayed due to finite processing speeds and the need to transmit data over nonzero distances. These time-delays often destabilize the network's dynamics, but are difficult to analyze because they increase the dimension of the network.We present results outlining an alternative means of analyzing these networks, by focusing analysis on the Lipschitz matrix of the relatively low-dimensional undelayed network. The key criteria, intrinsic stability, is computationally efficient to verify by use of the power method. We demonstrate applications from control theory and neural networks.

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Using Symmetry To Accelerate Materials Discovery, Wiley Spencer Morgan Apr 2019

Using Symmetry To Accelerate Materials Discovery, Wiley Spencer Morgan

Theses and Dissertations

Computational methods are commonly used by materials scientists to make predictions about materials. These methods can achieve in hours what would take days or weeks to accomplish in a lab. However, there are limits to what computational methods can do and how accurate the predictions are.A limiting factor for computational materials science is the size of the search space. The space of potential materials is infinite. Selecting specific systems of elements on a fixed lattice to study reduces the number of possible arrangements of atoms in the lattice to a finite number. However, this number can still be very large. …

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The Investigation Of Nickel-Based Catalysts For The Oxidative Dehydrogenation Of Ethane, Justin Lane Park Apr 2019

The Investigation Of Nickel-Based Catalysts For The Oxidative Dehydrogenation Of Ethane, Justin Lane Park

Theses and Dissertations

The Investigation of Nickel-Based Catalysts for the Oxidative Dehydrogenation of Ethane Justin Lane ParkDepartment of Chemistry & Biochemistry, BYU Doctor of Philosophy Chemistry The advancement of creating ethylene from ethane via oxidative dehydrogenation (ODH) rather than the traditional direct dehydrogenation is right on the cusp of commercialization. The oxidative pathway provides a novel route that reduces the operating temperature of this reaction by 400-500°C. A variety of metals including Mo, V, and Ni that have redox properties suitable for the partial oxidation of small chain alkanes have been investigated. Currently, a MoVNbTe oxide is the most promising catalyst but it …

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Deep Learning For Document Image Analysis, Christopher Alan Tensmeyer Apr 2019

Deep Learning For Document Image Analysis, Christopher Alan Tensmeyer

Theses and Dissertations

Automatic machine understanding of documents from image inputs enables many applications in modern document workflows, digital archives of historical documents, and general machine intelligence, among others. Together, the techniques for understanding document images comprise the field of Document Image Analysis (DIA). Within DIA, the research community has identified several sub-problems, such as page segmentation and Optical Character Recognition (OCR). As the field has matured, there has been a trend of moving away from heuristic-based methods, designed for particular tasks and domains of documents, and moving towards machine learning methods that learn to solve tasks from examples of input/output pairs. Within …

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After Https: Indicating Risk Instead Of Security, Matthew Wayne Holt Apr 2019

After Https: Indicating Risk Instead Of Security, Matthew Wayne Holt

Theses and Dissertations

Browser security indicators show warnings when sites load without HTTPS, but more malicious sites are using HTTPS to appear legitimate in browsers and deceive users. We explore a new approach to browser indicators that overcomes several limitations of existing indicators. First, we develop a high-level risk assessment framework to identify risky interactions and evaluate the utility of this approach through a survey. Next, we evaluate potential designs for a new risk indicator to communicate risk rather than security. Finally, we conduct a within-subjects user study to compare the risk indicator to existing security indicators by observing participant behavior and collecting …

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