Physical Sciences and Mathematics Commons^™

Deep Learning With Attention Mechanisms In Breast Ultrasound Image Segmentation And Classification, Meng Xu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Breast cancer is a great threat to women’s health. Breast ultrasound (BUS) imaging is commonly used in the early detection of breast cancer as a portable, valuable, and widely available diagnosis tool. Automated BUS image analysis can assist radiologists in making accurate and fast decisions. Generally, automated BUS image analysis includes BUS image segmentation and classification. BUS image segmentation automatically extracts tumor regions from a BUS image. BUS image classification automatically classifies breast tumors into benign or malignant categories. Multi-task learning accomplishes segmentation and classification simultaneously, which makes it more appealing and practical than an either individual task. Deep neural …

Investigating The Effect Of Greediness On The Coordinate Exchange Algorithm For Generating Optimal Experimental Designs, William Thomas Gullion

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Design of Experiments (DoE) is the field of statistics concerned with helping researchers maximize the amount of information they gain from their experiments. Recently, researchers have been turning to optimal experimental designs instead of classical/catalog experimental designs. One of the most popular algorithms used today to generate optimal designs is the Coordinate Exchange (CEXCH) Algorithm. CEXCH is known to be a greedy algorithm, which means it tends to favor immediate, locally best designs instead of globally optimal designs. Previous research demonstrated that this tradeoff was efficacious in that it reduced the cost of a single run of CEXCH and allowed …

Adversarial Swarming: A Groundwork For Multi-Drone Independent Interception Exercises Through Ma-Poca In Unity, Johnathan D. Kunz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As drones become more popular and easier to use, air spaces are becoming more congested. Airports, hospitals, and similar structures require controlled, safe airspaces and drones are increasingly a threat. Locally controlled airspace requires efficient removal of airborne threats to continue sensitive operations. Many methods have been investigated for removing drones from contested airspace. Generally these methods involve ground-based signal disruption, physical contact, or drone interception of a single intruder. In this work we present a drone interception model with a low-cost, low-capability group of short-range drones intercepting an incoming drone.

Generative Neural Network Approach To Designing And Optimizing Dynamic Inductive Power Transfer Systems, Andrew Pond Curtis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Electric vehicles (EVs) offer many improvements over traditional combustion engines including increasing efficiency, while decreasing cost of operation and emissions. There is a need for the development of cheap and efficient charging systems for the future success of EVs. Most EVs currently utilize static plug-in charging systems. An alternative charging method of significant interest is dynamic inductive power transfer systems (DIPT). These systems utilize two coils, one placed in the vehicle and one in the roadway to wirelessly charge the vehicle as it passes over. This method removes the current limitations on EVs where they must stop and statically charge …

Cross-Boundary Stewardship In Protected Area Centered Ecosystems: Perceptions Of Success And Characteristics Of Cooperative Engagement, Ryan D. Tarver

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The legal boundaries of protected areas, such as national parks are established and enforced by humans. Therefore, jurisdictional boundaries are ultimately have human meaning but not necessarily ecological relevance as natural phenomena such as watersheds and wildlife habitat often extend beyond a jurisdictional boundary. When considering the extent of natural system, we find that protected areas only make up part of a given ecosystem. The result is a large expanse of lands that fall under a various ownership types that include both publicly and privately designated tracts of land. This presents a management challenge when attempting to manage at the …

Examining Political Discourse On Online 8kun And Reddit Forums, Braden Mindrum

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A recent example of political violence in the United States was that of the January 6, 2021, Capitol attack in connection with the certification of Joseph R. Biden’s victory over Donald J. Trump in the 2020 US presidential election. This thesis analyzes the events of January 6, 2021, through the lens of social media discourse. This thesis presents a workflow that acquired over 5 million 8kun and Reddit posts from various apolitical and political forums in the three months preceding and following the Capitol attack on January 6, 2021. Techniques from text analysis are then used to group forums according …

Regeneration Of Quaking Aspen And Understory Vegetation Change After Fire Risk Reduction Treatment, Allison M. Trudgeon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Quaking aspen (Populus tremuloides Michx.) is a keystone species that, when coexisting with conifers (i.e., seral aspen), often undergoes stand-replacing disturbances to sustain long term vigor. Historically, mixed-to-high severity fire reduced fuels and regenerated aspen, but such disturbances have become less common in recent decades. This has often led to high fuel loading, and many seral aspen stands are at now risk of an unpredictable, high-severity fire, posing a threat to development in the wildland-urban-interface. The lack of a commercial market for aspen, and the risk of conducting prescribed fire, means there are few alternate management options. This has …

A Frobenius-Schur Extension For Real Projective Representation, Levi Gagnon‐Ririe

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many problems in physics have explicit mathematical descriptions. This thesis aims to provide the mathematical tools for a particular problem in physics, that of Quantum Mechanical symmetries. In essence, we extend the known mathematics to a more general setting and provide a wider view of Real projective representation theory. The work done in this thesis contributes to the subfield of mathematics known as representation theory and to the subfield of physics concerned with time reversal symmetry.

From Mountain Streams To Urban Rivers: An Assessment Of Microplastic Sources And Characteristics, Macy Gustavus

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plastic products are produced and discarded at an alarming rate. Bottles, bags, toys, and clothing break down into tiny plastic pieces called microplastics, ranging in size from an eraser on the top of a pencil to smaller in size than a red blood cell. Microplastics are becoming so common in the environment that they travel in the atmosphere, rivers, and ocean currents in ways that are similar to other types of Earth Systems Cycles (i.e., the water cycle). In this study, we explored microplastic sources and sinks in a freshwater river system and how seasonal changes in discharge affect how …

A Classification Of Tensors In Ecsk Theory, Joshua James Leiter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

You might have heard of Einstein’s theory of General relativity (GR): it is the one where mass and energy curve the fabric of spacetime to create gravity. This is the major theory which allows communication through satellites and our GPS to work too! Wormholes have interested me, but there are some issues about forming them in GR. Interestingly enough, elementary particles are also characterized by their spin in the standard model. However, intrinsic spin is nowhere geometrically coupled to the geometry of spacetime in Einstein’s theory. Later, Élie Cartan, Dennis Sciama, and Tom Kibble all flushed out adding different aspects …

Recreational Fishing Participation In Utah: Comparing Active And Non-Active Angler Constraint Perceptions With The Use Of License Purchase Data, Will Rempel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As a leisure activity, recreational fishing provides numerous social, physical, and psychological benefits to its participants. It can also provide socioeconomic opportunities to specific communities, and as an outdoor activity can create support for natural fisheries resources and public lands. License and equipment taxes are also important funding mechanisms for state wildlife managers. Though fishing participation as a percentage of the population has overall decreased in the last century, there is a recent increase in fishing participation. However, participation dynamics result in a shifting cycle of entries, departures, and re-entries to the sport. In an effort to maintain participation and …

The Concept Of Multicenter Bonds In Chemistry And Materials Science, Nikolay V. Tkachenko

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Chemical bonds are components of a universal and compact language of chemistry that was empirically developed before the modern concepts of quantum physics. This language explains how molecules and solids keep together. In particular, Lewis’s shared electron-pair bonding model may be considered the most successful and generally accepted theory of chemical bonding due to its simplicity and predictive power. However, there is an entire world of chemical species where the classical Lewis bonding language fails to describe the bonding pattern adequately. Those cases include but are not limited to compounds with a significant electron delocalization (where electron density spread on …

Practical Improvements For Pivot And Surface Irrigation, Jonathan A. Holt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Irrigation is critical to meeting global food and fiber demands. Optimizing agricultural irrigation may help sustain production levels, while reducing its demand for water. This research evaluated precision sprinklers and drip irrigation for pivots, five pivot track mitigation tools, three scientific irrigation scheduling (SIS) methods, sensors for surface irrigation cutoff, and automating surface systems to implement surge irrigation. With pivots and surface irrigation being the most common methods for irrigation in the West, small improvements from these tools could result in significant water savings.

Low energy precision application (LEPA) sprinklers and mobile drip irrigation (MDI) were tested on two pivots. …

Human Appropriation Of Net Primary Production Through Crops, Grazing, And Forestry In The U.S. From 1997 To 2012, Suman Paudel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation conducts a county-level analysis of human appropriation of net primary production (HANPP) harvested from crops, timber and grazing in the conterminous United States in the years 1997, 2002, 2007 and 2012. This study consists of three manuscripts (Chapters 2, 3, and 4). The first study quantifies net primary production in US counties in 1997, 2002, 2007 and 2012. The detailed HANPP study conducted concludes that HANPP is a valuable footprint tool for analyzing land use intensity and agricultural ecosystems. The second manuscript shows how HANPP is an improved or modernized ecological footprint and is a sustainable indicator as …

Graviweak Theory In Bicomformal Space, Mubarak Ukashat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

There are four basic forces in nature: the electromagnetic force, which accounts for interactions of particles with charges; the weak force, which is responsible for radioactive decay; the strong force, which holds the particles inside a nucleus tightly bound together; and the gravitational force, which is responsible for keeping us on our beautiful planet, Earth and holding together our entire solar system. Physicists have been on the hunt for a theory that can single-handedly explain all these forces under the same underlying mathematical formulation. So far, physicists have suceeded in unifying the electromagnetic and weak forces in what is called …

Statistical Challenges And Methods For Missing And Imbalanced Data, Rose Adjei

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Missing data remains a prevalent issue in every area of research. The impact of missing data, if not carefully handled, can be detrimental to any statistical analysis. Some statistical challenges associated with missing data include, loss of information, reduced statistical power and non-generalizability of findings in a study. It is therefore crucial that researchers pay close and particular attention when dealing with missing data. This multi-paper dissertation provides insight into missing data across different fields of study and addresses some of the above mentioned challenges of missing data through simulation studies and application to real datasets. The first paper of …

Data Visualization, Dimensionality Reduction, And Data Alignment Via Manifold Learning, Andrés Felipe Duque Correa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The high dimensionality of modern data introduces significant challenges in descriptive and exploratory data analysis. These challenges gave rise to extensive work on dimensionality reduction and manifold learning aiming to provide low dimensional representations that preserve or uncover intrinsic patterns and structures in the data. In this thesis, we expand the current literature in manifold learning developing two methods called DIG (Dynamical Information Geometry) and GRAE (Geometry Regularized Autoencoders). DIG is a method capable of finding low-dimensional representations of high-frequency multivariate time series data, especially suited for visualization. GRAE is a general framework which splices the well-established machinery from kernel …

Bifurcations And Hysteresis In The Dynamics Of Small Populations Of Spherical Magnets, Peter T. Haugen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

If you heat up some kinds of metals and then cool them down next to a magnet, they will be a magnet when they cool, but if they cool down away from a magnet, they will just be a lump of metal. This is an example of hysteresis and it’s very important for lots of technology. Another example of hysteresis might be a water tower pump that turns on when the tower is nearly empty and keeps going until the tower is nearly full. Whether or not the pump is on when the tower is half full depends on what …

Pleistocene Deposits Of Lower Wahweap Creek And Its Tributaries, Southern Utah, Noah Slade

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The famous landscapes of the Colorado Plateau have been created over millions of years, primarily by erosive forces of wind and water. Interruptions in the long-term erosion of the landscape occur when streams gain more sediment than they can transport, which causes deposition along channels and floodplains. The resulting sequences of terrace deposits are used by geologists to study when and how river systems have evolved.

Mammoth bones were recently discovered in stream deposits along Wahweap Creek, a tributary of the Colorado River in southern Utah. Previous work indicates that the deposits pre-date the last ice age, making it one …

Old-Growth Forest Dynamics After Fire And Drought In The Sierra Nevada, California, Usa, Kendall M.L. Becker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding forest ecosystems is important because forests cover approximately one-third of Earth’s land area, store half of Earth’s carbon, shelter half of Earth’s species, and absorb a quarter of new anthropogenic carbon emissions, slowing climate change. This dissertation provides insight into future forest habitat, fuels, species composition, and structure by investigating what happens to snags, seedlings, and trees in an old-growth forest after a low- to moderate-severity fire.

Chapter II explores how low- to moderate-severity fire changes snag fall rates. Predicting how long snags will remain standing after fire is essential for managing habitat, understanding chemical cycling in forests, and …

Late Pleistocene Piedmont Records In The Grand Staircase Region, Southern Utah, Alexander K. Short

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Today the climate in the southwestern United States is arid, characterized by desert landscapes and habitats, periods of drought, and arroyo streams that frequently fill with, and erode, through fine riverbed sediments. A series of cliffs and benches rising from the Grand Canyon to the southern plateaus of Utah, known as the Grand Staircase - home to Kodachrome Basin State Park, Bryce Canyon, are a classical example of this environment as we know it today. However, a record spanning the past 300 thousand years is preserved on the steps of the staircase indicating periods in the past where the climate …

Design Of Environment Aware Planning Heuristics For Complex Navigation Objectives, Carter D. Bailey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A heuristic is the simplified approximations that helps guide a planner in deducing the best way to move forward. Heuristics are valued in many modern AI algorithms and decision-making architectures due to their ability to drastically reduce computation time. Particularly in robotics, path planning heuristics are widely leveraged to aid in navigation and exploration. As the robotic platform explores and navigates, information about the world can and should be used to augment and update the heuristic to guide solutions. Complex heuristics that can account for environmental factors, robot capabilities, and desired actions provide optimal results with little wasted exploration, but …

Bedrock Geology Map Of The Naomi Peak 7.5' Quadangle, Cache County, Utah And Novel Age Constraints On Its Cambrian Strata, Hannah R. Cothren

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Geologists use various “rock-clocks” in order to interpret the timing and tempo of events in Earth’s history. These include global geochemical events in the oceans (chemostratigraphy), the evolution of certain fossil species (trilobite biostratigraphy), and the radiogenic decay of uranium to lead in certain mineral such as zircon (U-Pb geochronology). Integrating these methods in the stratigraphic record in one location can provide a well-constrained timeline for a select part of the Geologic, or Deep Time, record. This technique is especially important in the Cambrian Period (538.8 to 486.9 million years; Ma), which sets the stage for life today with the …

Investigating The Use Of Quartz Luminescence And Rock-Color Alteration To Characterize Wildfire Exposure; Applied To The 2020 Mangum Fire, Kaibab Plateau, Arizona, April I. Phinney

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wildfires appear to be increasing in size, severity, and frequency. Land managers need information on past wildfire behavior to make effective and adaptive land management plans. However, there are only a few techniques and data sources that provide information on past fire heating. This study aims to provide new methods to equip managers with a more robust understanding of historic and modern fire behavior. Fire behavior is assessed using novel methods that can assess soil and rock response to past wildfire heat exposure.

This study examined samples from the 2020 Mangum Fire, in northern Arizona. Sediment and rock were gathered …

Normative Evaluations Of Resource Conditions: The Influence Of Visitor Characteristics And Implications For Recreation Management In Urban-Proximate Parks, Jordan E. Nesbitt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Urban-proximate parks and protected areas provide a unique recreation landscape to individuals living in and near urban centers. They have been shown to provide similar recreation experiences to traditionally studied parks and protected areas such as National Parks, National Forests and Wilderness areas. This study takes place in a set of four urban-proximate parks in Orange County, California, USA. These parks are designated as urban-proximate because they are located within 100 miles of an urban center with 1 million or more people. Using norm theory, a well vetted social science theory, this work sought to identify thresholds of acceptability for …

Temperature Dependent Density Of States Models And Compiled Data For Radiation Induced Conductivity, Jodie Gillespie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Radiation Induced Conductivity (RIC) is the change in conductivity of a material due to bombardment from incident high energy radiation. RIC has consistently been found to follow a standard power law relation, 𝜎_𝑅𝐼𝐶(𝑇) = 𝑘_𝑅𝐼𝐶(𝑇)Ḋ^∆(𝑇), between conductivity, 𝜎_𝑅𝐼𝐶 and adsorbed dose rate, Ḋ. 𝑘_𝑅𝐼𝐶(𝑇) and ∆(𝑇) are material dependent parameters. Previous RIC models were developed in the 𝑇 → 0 limit. Now expanded models are developed in the low temperature limit (within a few 𝑘_𝐵𝑇 of the effective Fermi level) by approximating the Fermi-Dirac equation within a …

River Response To Sediment Supply: The Sand Bed Case, Christina M. Leonard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Effective management of in-channel and floodplain habitat requires an ability to forecast river response to changes in water and sediment supply. These changes may result from dam construction/decommissioning, changes in reservoir operations, or changes in grazing or forestry practices. If a change in water and sediment supply causes sediment to be delivered faster than the channel’s capacity to transport it, sediment will accumulate in the reach, leading to changes in channel form and increasing the potential for flooding. A decrease in sediment supply relative to transport capacity can lead to channel incision. The extent and timing of sediment accumulation or …

Investigating Atmospheric Gravity Waves Using 3-Dimensional Spectral Analysis, Kenneth I. Zia

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Atmospheric gravity waves (GW) are generated from the ground and go into the upper layers of the atmosphere where space begins. These waves have strong effects on the temperature and circulation of the Earth’s atmosphere. The temperature changes caused by these waves are observed through special cameras looking at light that the Earth’s atmosphere naturally emit at night. One of these cameras is placed at McMurdo Station, Antarctica where the long nights are used to see these waves longer than anywhere else. The images captured there are automatically analyzed to determine wave properties to better understand how often they are …

Functional Characterization Of The Newly Discovered Type V Crispr-Cas Protein Cas12a2, Dylan J. Keiser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Similarly to people, bacteria are under the treat of infection by viruses. To circumvent these threats, bacteria evolve complex immune systems. Our understanding of some of these immune systems has led to many advancements in the field of Biotechnology including tools that made expressing proteins for study in a lab easier, tools that revolutionized the feasibility of gene editing, and tools that could change the way we think about viral diagnostics and cancer therapeutics. A certain type of immune system that bacteria use to fight virus is called a CRISPR system. Presented here is work to understand the function of …

Carbon Sinks And Sources In Great Salt Lake: Consequences Of Declining Lake Levels, Melissa Cobo Arias

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Globally, saline lakes are experiencing declining water level as a consequence of climate change, water diversions for human consumption, and management strategies that do not account for changing climate and drought conditions. Great Salt Lake (GSL) is a large saline lake in Utah, USA, and is, as most saline lakes, experiencing decreasing lake levels which may impact local carbon cycling. It is unknown how lakebed drying affects processes that control carbon sequestration and carbon emissions to the atmosphere. The goal of this research was to measure various biological processes that use, create, and transform carbon in GSL to understand the …