Physical Sciences and Mathematics Commons^™

Analysis Of Total Electron Content (Tec) Variations In The Low- And Middle-Latitude Ionosphere, Ja Soon Shim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Detailed study of the spatial correlations of day-to-day ionospheric TEC variations on a global scale was performed for four 30-day-long periods in 2004 (January, March/April, June/July, September/October) using observations from more than 1000 ground-based GPS receivers. In order to obtain the spatial correlations, initially, the day-to-day variability was calculated by first mapping the observed slant TEC values for each 5-minute GPS ground receiver-satellite pair to the vertical and then differencing it with its corresponding value from the previous day. This resulted in more than 150 million values of day-to-day change in TEC (delta TEC). Next, statistics were performed on the …

Exploring The Spawning Dynamics And Identifying Limitations To The Early Life-History Survival Of An Important, Endemic Fish Species, Sara Elizabeth Seidel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

For many native, imperiled salmonid species, the prioritization of recovery and conservation efforts hinges upon the identification of a species most limiting life stage. The early life-history stage can be a limiting life stage for fish, and given the importance of the reproductive stage to overall persistence, there is a need to better understand the spawning ecology and early life history of many salmonids. The Logan River, in northern Utah, contains one of the largest metapopulations of imperiled Bonneville cutthroat trout (BCT) throughout the Bonneville Basin. Little research has evaluated the temporal and spatial distribution of BCT spawning nor quantified …

A Computational Geometry Approach To Digital Image Contour Extraction, Pedro J. Tejada

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We present a method for extracting contours from digital images, using techniques from computational geometry. Our approach is different from traditional pixel-based methods in image processing. Instead of working directly with pixels, we extract a set of oriented feature points from the input digital images, then apply classical geometric techniques, such as clustering, linking, and simplification, to find contours among these points. Experiments on synthetic and natural images show that our method can effectively extract contours, even from images with considerable noise; moreover, the extracted contours have a very compact representation.

Evolution Of The Lower Cretaceous Chifeng Half-Graben Basins, Inner Mongolia, China, Scott Joshua Friedman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As a result of complex extensional tectonics in northeast China and southern portions of Mongolia, some workers have interpreted the Cretaceous Maanshan Uplift and associated Chifeng basins as metamorphic core complex. Previous work has relied solely upon kinematic indicators to determine the structural origin of these basins. To fully understand the creation of these basins, the sedimentiological record was analyzed in this study. The early Cretaceous sedimentary fill of these basins was analyzed to determine if it is synextensional in nature, and if so what manner of extension was in progress during that deposition.

The Chifeng basins are filled with …

Symmetry Analysis Of General Rank-3 Pfaffian Systems In Five Variables, Francesco Strazzullo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this dissertation we applied geometric methods to study underdetermined second order scalar ordinary differential equations (called general Monge equations), nonlinear involutive systems of two scalar partial differential equations in two independent variables and one unknown and non-Monge-Ampere Goursat parabolic scalar PDE in the plane. These particular kinds of differential equations are related to general rank-3 Pfaffian systems in five variables. Cartan studied these objects in his 1910 paper. In this work Cartan provided normal forms only for some general rank-3 Pfaffian systems with 14-, 7-, and 6-dimensional symmetry algebra.

In this dissertation we provided normal forms of all general …

Geochemical Provenance Of Clastic Sedimentary Rocks In The Western Cordillera: Utah, Colorado, Wyoming, And Oregon, John Aaron Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sedimentary rocks are an important source of information about previous orogenic conditions and the composition of which may describe the evolution of provenance and tectonic setting. Many factors influence sediment composition, namely, source rock composition, chemical weathering, climate, transport burial, and diagenesis. As the sediment composition changes through time, the geochemical characteristics of the sediment can be used to understand its geologic history.

The geochemical characteristics of clastic sedimentary rocks are useful in determining the depositional setting and its associated provenance. Although many different studies have used geochemical discriminants to evaluate provenance and tectonic settings, none have used a defined …

A Methodology To Design Pipelined Simulated Annealing Kernel Accelerators On Space-Borne Field-Programmable Gate Arrays, Jeffrey Michael Carver

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Increased levels of science objectives expected from spacecraft systems necessitate the ability to carry out fast on-board autonomous mission planning and scheduling. Heterogeneous radiation-hardened Field Programmable Gate Arrays (FPGAs) with embedded multiplier and memory modules are well suited to support the acceleration of scheduling algorithms. A methodology to design circuits specifically to accelerate Simulated Annealing Kernels (SAKs) in event scheduling algorithms is shown. The main contribution of this thesis is the low complexity scoring calculation used for the heuristic mapping algorithm used to balance resource allocation across a coarse-grained pipelined data-path. The methodology was exercised over various kernels with different …

Nitrogen Transport, Transformation And Cycling Through A Mountain Lake, Bull Trout Lake, Idaho, Usa, Ryan Settle Lockwood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of a mountain lake on nitrogen dynamics in a sub-alpine watershed were examined via watershed monitoring, mesocosm experiments, microcosm experiments, and enzymatic assays during spring and summer of a single year. Our study addressed the questions: (1) How does hydrologic transport through the lake affect the net fluxes of dissolved nitrogen (N) species? (2) What are the net effects of the littoral zone biota on dissolved N fluxes? (3) What are the seston and benthic uptake rates of nitrate? (4) What is the magnitude of N retention in littoral zone sediments? (5) What role does microbial hydrolysis of …

Rayleigh-Lidar Observations Of Mesospheric Gravity Wave Activity Above Logan, Utah, Durga N. Kafle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A Rayleigh-scatter lidar operated from Utah State University (41.7°N, 111.8°W) for a period spanning 11 years ― 1993 through 2004. Of the 900 nights observed, data on 150 extended to 90 km or above. They were the ones used in these studies related to atmospheric gravity waves (AGWs) between 45 and 90 km. This is the first study of AGWs with an extensive data set that spans the whole mesosphere. Using the temperature and temperature gradient profiles, we produced a climatology of the Brunt-Väisälä (buoyancy) angular frequency squared, N² (rad/s)². The minimum and maximum values of N …

Object Trajectory Estimation Using Optical Flow, Shuo Liu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Object trajectory tracking is an important topic in many different areas. It is widely used in robot technology, traffic, movie industry, and others. Optical flow is a useful method in the object tracking branch and it can calculate the motion of each pixel between two frames, and thus it provides a possible way to get the trajectory of objects. There are numerous papers describing the implementation of optical flow. Some results are acceptable, but in many projects, there are limitations. In most previous applications, because the camera is usually static, it is easy to apply optical flow to identify the …

Soil Organic Carbon And Site Characteristics In Aspen And Evaluation Of The Potential Effects Of Conifer Encroachment On Soil Properties In Northern Utah, Mical K. Woldeselassie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the Intermountain West, aspen (Populus tremuloides) has declined mainly due to a combination of successional processes, fire suppression and long-term use of ungulates which has led to replacement by conifers, sagebrush or other shrub communities. Conifer encroachment is believed to cause critical changes in the ecosystem properties. In order to understand the impacts of conifer encroachment on soil properties such as soil organic carbon (SOC) storage, soil morphology, and soil chemical properties, and the implications of such changes, it is very important to assess the soil properties under the two vegetation types. The objectives of this study …

Carbohydrate Derivatives In Antibiotics Research, Yi Liang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this study, we investigated the potential applications of carbohydrates in the development of new antibiotics. To tackle the problem of multidrug-resistant variants of M. tuberculosis (MDR-TB), we investigated the biosynthesis pathways of trehalose, which has contributed to significant drug resistance. Some new methods were developed for the synthesis of potential inhibitors (6-azido-trehalose and 6,6'-diazido-trehalose) that have been designed to imitate the intermediate molecule (trehalose 6-phosphate, TPP) of OtsA-OtsB pathway. At the same time, some new antibacterial agents based on trehalose have been synthesized. Members of the 1,2,3-triazole family have shown interesting biological properties. Steroid derivatives have been developed in …

Fluvial Systems Tied Together Through A Common Base Level: The Geomorphic Response Of The Dirty Devil River, North Wash Creek, And The Colorado River To The Rapid Base Level Drop Of Lake Powell, Adam L. Majeski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fluvial adjustment to base level change has its roots in the fundamental concepts of geomorphology. This thesis explores the rate of erosion and sedimentation on the Colorado and Dirty Devil rivers and North Wash Creek under the current base level changes related to the drawdown conditions of Lake Powell. Through cross section and long profile resurveys, the current state of each system is captured and added to the historic record of sedimentation in Lake Powell. All three systems are generally forming narrow and deep incised channels driven by the rapid rate of base level fall. Cross sections that deviate from …

On The Applicability Of Genetic Algorithms To Fast Solar Spectropolarimetric Inversions For Vector Magnetography, Brian J. Harker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The measurement of vector magnetic fields on the sun is one of the most important diagnostic tools for characterizing solar activity. The ubiquitous solar wind is guided into interplanetary space by open magnetic field lines in the upper solar atmosphere. Highly-energetic solar flares and Coronal Mass Ejections (CMEs) are triggered in lower layers of the solar atmosphere by the driving forces at the visible ``surface'' of the sun, the photosphere. The driving forces there tangle and interweave the vector magnetic fields, ultimately leading to an unstable field topology with large excess magnetic energy, and this excess energy is suddenly and …

A Comparative Study Of The Structural Features And Kinetic Properties Of The Mofe And Vfe Proteins From Azotobacter Vinelandii, Miguel Alejandro Pabon Sanclemente

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Biological nitrogen fixation is accomplished in the bacterium Azotobacter vinelandii by means of three metalloenzymes: The molybdenum, vanadium, and iron-only nitrogenase. The knowledge regarding biological nitrogen fixation has come from studies on the Mo-dependent reaction. However, the V- and Fe-only-dependent reduction of nitrogen remains largely unknown.

By using homology modeling techniques, the protein folds that contain the metal cluster active sites for the V- and Fe-only nitrogenases were constructed. The models uncovered similarities and differences existing among the nitrogenases regarding the identity of the amino acid residues lining pivotal structural features for the correct functioning of the proteins. These differences, …

Novel Growth Of Ingaas/Gaas Nanostructures By Molecular Beam Epitaxy, Dong Jun Kim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation presents an extensive study of the epitaxial growth mechanism by a novel growth method. This novel growth method was developed at Utah State University and is a modification of the Stranski-Krastanov (S-K) growth mode. Our new growth method consists of a two-step process, low temperature growth and high temperature annealing. During low temperature growth, diffusion is minimized, resulting in the deposition of a pseudomorphic epilayer. During high temperature annealing, diffusion is induced from the pseudomorphic epilayer, resulting in the transformation of the epilayer into nanostructures. Benefits of this novel growth method are a significantly smaller segregation and suppressed …

Predicting The Growth Potential Of A Shallow, Warm-Water Sport Fishery: A Spatially Explicit Bioenergetics Approach, Samuel Kirk Dahle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Capturing the range of fish consumption and growth potential of large, heterogeneous lentic systems can be challenging due to strong gradients in productivity, the diversity of habits types present, and in some cases, site-specific water quality issues. Cutler Reservoir (Utah, USA) displays a high degree of spatial and temporal variation in physical conditions and potential water quality limitations for fish, including high summertime water temperature and large, diel fluctuations in dissolved oxygen concentrations. The combination of bioenergetics modeling and GIS spatial analysis offers a promising interface for quantifying the fish consumptive and growth potential across a spatially and temporally heterogeneous …

A Novel Technique Of Network Auditability With Managers In The Loop, Rian Shelley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Network management requires a large amount of knowledge about the network. In particular, knowledge about used network addresses, access time, and topology is useful. In a network composed of managed devices, much of the data necessary can come from simple network management protocol (SNMP) queries. Other data can come from other databases, or analysis of existing data. In particular, layer-two network topology can be determined by analyzing the mac address forwarding tables of layer-two devices. The layer-two topology can be merged with a layer-three topology to generate a complete topology of the network. This information is useless unless it is …

Forensic And Anti-Forensic Techniques For Object Linking And Embedding 2 (Ole2)-Formatted Documents, Jason M. Daniels

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Common office documents provide significant opportunity for forensic and anti-forensic work. The Object Linking and Embedding 2 (OLE2) specification used primarily by Microsoft’s Office Suite contains unused or dead space regions that can be over written to hide covert channels of communication. This thesis describes a technique to detect those covert channels and also describes a different method of encoding that lowers the probability of detection.

The algorithm developed, called OleDetection, is based on the use of kurtosis and byte frequency distribution statistics to accurately identify OLE2 documents with covert channels. OleDetection is able to correctly identify 99.97 percent of …

Application Of Resiliency Theory And Adaptive Cycles As A Framework For Evaluating Change In Amenity-Transition Communities, Scott L. Hoffmann

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In recent decades, many rural, natural resource-dependent communities have experienced ubiquitous and oftentimes substantial economic decline due to downturns in their commodity-oriented industries. In spite of this, communities with access to varying forms of natural capital have experienced an upsurge in activities such as recreation, tourism, second home growth, and retirement in-migration. If managed properly, amenity-oriented development has potential to reverse economic decline by attracting tourists, entrepreneurs, younger and more educated workers, and retirees, and may ultimately generate economic diversification, local growth, and an improved quality of life for residents. While there are literally thousands of potential measures of well-being, …

An Evolutionary Approach To Image Compression In The Discrete Cosine Transform Domain, Benjamin E. Banham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This paper examines the application of genetic programming to image compression while working in the frequency domain. Several methods utilized by JPEG encoding are applied to the image before utilizing a genetic programming system. Specifically, the discrete cosine transform (DCT) is applied to the original image, followed by the zig-zag scanning of DCT coefficients. The genetic programming system is finally applied to the one-dimensional array resulting from the zig-zag scan. The research takes an existing genetic programming system developed for the spatial domain and develops DCT domain functionality. The results from the DCT domain-based genetic programming system are compared with …

Automated Data Type Identification And Localization Using Statistical Analysis Data Identification, Sarah Jean Moody

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research presents a new and unique technique called SÁDI, statistical analysis data identification, for identifying the type of data on a digital device and its storage format based on data type, specifically the values of the bytes representing the data being examined. This research incorporates the automation required for specialized data identification tools to be useful and applicable in real-world applications. The SÁDI technique utilizes the byte values of the data stored on a digital storage device in such a way that the accuracy of the technique does not rely solely on the potentially misleading metadata information but rather …

Sedimentology, Stratigraphy, And Organic Geochemistry Of The Red Pine Shale, Uinta Mountains, Utah: A Prograding Deltaic System In A Mid-Neoproterozoic Interior Seaway, Caroline Amelia Myer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Red Pine Shale (RPS; ~1120m thick), uppermost formation of the Neoproterozoic Uinta Mountain Group, Utah, is an organic-rich sedimentary succession interpreted as a marine deltaic system that delivered immature sediment from the north that mixed with mature sediment from the east. Multiple data sets suggest regional climate and sea-level changes associated with changing organic-carbon burial rates.

Six facies were identified and represent wave-, tidal-, and river-influenced parts of the distal prodelta to delta front in a marine system. These include the shale facies and associated concretion facies (distal prodelta), the shale-sandstone facies (proximal prodelta to delta front), the slump …

Hydrological Characterization Of A Riparian Vegetation Zone Using High Resolution Multi-Spectral Airborne Imagery, Osama Zaki Akasheh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Rio Grande River (MRGR) is the main source of fresh water for the state of New Mexico. Located in an arid area with scarce local water resources, this has led to extensive diversions of river water to supply the high demand from municipalities and irrigated agricultural activities. The extensive water diversions over the last few decades have affected the composition of the native riparian vegetation by decreasing the area of cottonwood and coyote willow and increasing the spread of invasive species such as Tamarisk and Russian Olives, harmful to the river system, due to their high transpiration rates, …

A Three-Dimensional, Time-Dependent Circulation Model Of Utah Lake, Eric V. Callister

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spatial and temporal variations of Utah Lake’s flow field were modeled using the Estuary Lake and Computer Model from the Centre for Water Research (CWR-ELCOM) at the University of Western Australia as part of an effort to increase understanding of the lake’s natural processes in order to restore the lake to its pristine, clear-water state and preserve the habitat of the June sucker, an endangered species. The model was validated using temperature measurements taken by sensors in 2007. The water temperature was a strong function of air temperature and incident short wave radiation, and was influenced to a lesser degree …

Modeling The Electrodynamics Of The Low-Latitude Ionosphere, Christian Stephen Wohlwend

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The electrodynamics of the Earth's low-latitude ionosphere is dependent on the ionospheric conductivity and the thermospheric neutral density, temperature, and winds present. This two-part study focused on the gravity wave seeding mechanism of equatorial plasma depletions in the ionosphere and the associated equatorial spread F, as well as the differences between a two-dimensional flux tube integrated electrodynamics model and a three-dimensional model for the same time period. The gravity wave seeding study was based on a parameterization of a gravity wave perturbation using a background empirical thermosphere and a physics-based ionosphere for the case of 12 UT on 26 September …

Identification Of Subsoil Compaction Using Electrical Conductivity And Spectral Data Across Varying Soil Moisture Regimes In Utah, Jay Murray Payne

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Subsoil compaction is a major yield limiting factor for most agricultural crops. Tillage is the most efficient method to quickly treat compacted subsoil, but it is also expensive, increases erosion, and accelerates nutrient cycling.

The use of real-time electrical conductivity (EC) and near-infrared (NIR) reflectance values to differentiate compacted areas from uncompacted areas was studied. This method has potential to reduce monetary and time investments inherent in traditional grid sampling and the resultant deep tillage of an entire field. EC and NIR reflectance are both very sensitive to spatial variability of soil attributes.

The objective of this research was to …

Factors Affecting Landowner Participation In The Candidate Conservation Agreements With Assurances Program, Kendra Womack

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The United States’ Endangered Species Act of 1973 has been recognized as one of the most powerful laws enacted to protect endangered species in the world. Its protections for animal species extends onto private land, which has in some cases created conflict between the law, its enforcers, and private landowners. The Candidate Conservation Agreements with Assurances (CCAA) program was developed in 1999 to provide a regulatory incentive for private landowners to engage in pro-active conservation for sensitive species to preclude the need for listing under the ESA in the future. Since 1999, however, there have only been 17 CCAAs signed, …

Measurement Of Fine Spatial Scale Ecohydrologic Gradients In A Pinyon-Juniper Ecosystem, Matthew David Madsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

With the dramatic expansion of pinyon-juniper woodlands over the last century, improved understanding of how these woodlands modify infiltration properties is needed, in order for land managers to make informed decisions on how to best manage their specific resources. However, current methods for measuring soil infiltration are often limited by low sample sizes and high experimental error, due to constraints associated with remote, non agricultural settings. This thesis first presents a scheme for automating and calibrating two commercially available infiltrometers, which allows collection of a large number of precise unsaturated infiltration measurements in a relatively short period of time. Secondly, …

Analysis Of Chemical Bonding In Clusters By Means Of The Adaptive Natural Density Partitioning, Dmitry Yu Zubarev

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Models of chemical bonding are essential for contemporary chemistry. Even the explosive development of the computational resources including, both hardware and software, cannot eliminate necessity of compact, intuitive, and efficient methods of representing chemically relevant information. The Lewis model of chemical bonding, which was proposed eleven years before the formulation of quantum theory and preserves its pivotal role in chemical education and research for more than ninety years, is a vivid example of such a tool. As chemistry shifts to the nanoscale, it is becoming obvious that a certain shift of the paradigms of chemical bonding is inescapable. For example, …