Physical Sciences and Mathematics Commons^™

Graphshop: An Interactive Software Environment For Graph Theory Research And Applications, Aaron Andersen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Graph Theory is the mathematical study of the structure of abstract relationships between objects. Although these constructions (graphs) are themselves purely theoretical, their ability to model pair-wise relationships in systems of arbitrary complexity yields abundant direct correspondence with numerous important physical and societal systems in the real world. Additionally, the simple discrete nature of fundamental graph structures allows for easy pseudo-geometric visualization of graphs in a wide variety of ways. Taken together, these two properties suggest that graph theory teaching, research, and applications would benefit greatly from the use of a unified software environment for graph construction, interaction, and visualization. …

A Fully Automatic Segmentation Method For Breast Ultrasound Images, Juan Shan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Breast cancer is the second leading cause of death of women worldwide. Accurate lesion boundary detection is important for breast cancer diagnosis. Since many crucial features for discriminating benign and malignant lesions are based on the contour, shape, and texture of the lesion, an accurate segmentation method is essential for a successful diagnosis. Ultrasound is an effective screening tool and primarily useful for differentiating benign and malignant lesions. However, due to inherent speckle noise and low contrast of breast ultrasound imaging, automatic lesion segmentation is still a challenging task.

This research focuses on developing a novel, effective, and fully automatic …

Individualistic Response Of Piñon And Juniper Tree Species Distributions To Climate Change In North America's Arid Interior West, Jacob R. Gibson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Piñon and juniper tree species have species-specific climatic requirements, resulting in unique distributions and differential responses to climate change. Piñons and junipers co-dominate the arid woodlands of North America as groups with widespread hybridization. Two piñons, Pinus edulis; P. monophylla, and four junipers, Juniperus deppeana var. deppeana; J. monosperma; J. occidentalis; J. osteosperma, are endemic to the midlatitude interior west and form three groups of hybridizing sister species, P. edulis-P. monophylla; J. deppeana var. deppeana-J. monosperma; J. occidentalis-J. osteosperma. Recent droughts have caused widespread mortality among piñons, but have had less impact on …

Examining Child Sexual Abuse And Future Parenting: An Application Of Latent Class Modeling, Kimberly W. D'Zatko

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study was designed to empirically derive latent classes of mothers who were sexually abused during childhood and to assess the association between depression, alcohol/drug use, supportive intimate partner, and specific classes.

One hundred six women between the ages of 20 and 44 years (M = 27) who reported having been sexually abused during childhood (CSA) and 158 non-CSA mothers between the ages of 20 and 43 years (M = 23) were interviewed and assessed along six parenting dimensions. Logistic regression models evaluated the association between psychoemotional variables and specific classes.

The final model consisted of three classes—53.2%, …

Spatiotemporal Modeling Of Threats To Big Sagebrush Ecological Sites In Northern Utah, Alexander J. Hernandez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study tested the performance of classification, regression, and ordination techniques to evaluate the spatiotemporal dynamics of threats to big sagebrush ecological sites. The research was focused on invasion by annual exotic grasses and encroachment by woodlands.

We sought to identify those areas that have had a persistent coverage of cheatgrass (Bromus tectorum) in big sagebrush ecological sites. We took advantage of the contrast in greenness between multi-temporal (within one year) remotely sensed vegetation indices captured in the spring and summer to find a distinct phenological signature that allowed mapping cheatgrass. We utilized support vector machines (SVM) to classify three …

Sedimentological Controls On Fracture Distribution And The Network Development Within Meseverde Group Lithofacies, Uinta Basin, Utah, Ryan Christopher Sonntag

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Mesaverde Group, within the Uinta Basin, Utah, is a source of current significant production and contains several trillion cubic feet of undiscovered natural gas resources. Due to the low permeability of the matrix rock, understanding the geometry and properties of natural fractures is critical to the development of effective ways of finding and producing natural gas. In order to evaluate and model the potential connectivity of hydraulically induced fractures to natural fractures at depth, we examine the nature of the natural fracture network using scanline sampling, imagery analyses, core analyses, and microstructural analyses. Regional fracture sets identified include: N-S …

Statistical Analysis Of The Usu Lidar Data Set With Reference To Mesospheric Solar Response And Cooling Rate Calculation, With Analysis Of Statistical Issues Affecting The Regression Coefficients, Troy Alden Wynn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Though the least squares technique has many advantages, its possible limitations as applied in the atmospheric sciences have not yet been fully explored in the literature. The assumption that the atmosphere responds either in phase or out of phase to the solar input is ubiquitous. However, our analysis found this assumption to be incorrect. If not properly addressed, the possible consequences are bias in the linear trend coefficient and attenuation of the solar response coefficient.

Using USU Rayleigh lidar temperature data, we found a significant phase offset to the solar input in the temperatures that varies ±5 years depending on …

Who Wins And Who Loses? A Community Approach To Understanding The Well-Being Of Boomtown Residents, Douglas Alan Malloy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this thesis is to accurately identify residents of a boomtown who are either experiencing a higher level of well-being, or lower level of well-being. By definition, we consider the former to be winning, and the latter to be losing. Multivariate ordinary least squares regression analyses help to distinguish between winners and losers by generating statistical coefficients which will show both strength and direction of the relationship between individuals and various indicators of social well-being.

The data used in this thesis are from a community impact study issued in the spring of 2009, to residents of …

Estimates Of The Hydraulic Parameters Of Aquifers In Cache Valley, Utah And Idaho, Paul C. Inkenbrandt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Hydraulic parameters of aquifers in Cache Valley were compiled from existing but largely unpublished data, from specific capacity data reported in well drillers' records, and from aquifer tests conducted for this study. A GIS database was also created to organize this information.

A complete and thorough literature review was performed, which included obtaining unpublished aquifer test data from state and federal agencies, as well as reviewing Drinking Water Source Protection plans for each municipality in the valley.

Well drillers' records were obtained from the Utah Division of Water Rights website and examined for pertinent information. Screened unit intervals from 1,314 …

Assessing Linkages Among Landscape Characteristics, Stream Habitat, And Macroinvertebrate Communities In The Idaho Batholith Ecoregion, Andrew C. Hill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding the composition of lotic communities and the landscape processes and habitat characteristics that shape them is one of the main challenges confronting stream ecologists. In order to better understand the linkages among landscape processes, stream habitat, and biological communities and to understand how accurately our measurements represent important factors influencing biological communities, it is important to test explicit hypotheses regarding these linkages. Increasing our understanding of aquatic communities in a hierarchical context and recognizing how well our measurements represent factors structuring aquatic communities will help managers better evaluate the influence of land management practices on aquatic ecosystems, direct conservation …

Psychometric Properties Of Postsecondary Students' Course Evaluations, Michael J. Drysdale

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Several experts in the area of postsecondary student evaluations of courses have concluded that they are stable or reliable measures as well as being measures that provide ways of making valid inferences regarding teacher effectiveness. Often these experts have offered these conclusions without supporting evidence. Surprisingly, a thorough review of the literature revealed very few reported test-retest reliability studies of course evaluations and the results from these studies are contradictory. In the area of validity, the conclusions offered by scholars who conducted meta-analyses of mutlisection course studies are inconsistent. This leads to the following two research questions:

1. What is …

Conservation From The Bottom-Up: Human, Financial, And Natural Capital As Determinants Of Resilient Livelihoods In Kigoma Rural, Tanzania, Yared J. Fubusa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rhetoric of "community-based conservation" has gained prominence among development specialists and environmentalists, yet such projects are often implemented from the top-down in Africa. This dissertation contends that only a bottom-up approach can foster resilient livelihoods and environmental stewardship.

This study focused on determinants of household resilience within a poverty-stricken agricultural community near Gombe Stream National Park (GSNP) in western Tanzania. The research purpose was to explore: 1) relationships between villagers and GSNP management; 2) how groups and individuals view priority livelihood problems and solutions; 3) various attributes of households; and 4) perceived trends for household resilience and how these are …

Recreation Resource Impacts In The Bear Lake Road Corridor Of Rocky Mountain National Park, Colorado, Usa: An Assessment Of Resource Conditions And Visitor Perceptions, Ashley L. D'Antonio

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Visitor use in parks and protected areas inevitably leads to resource impacts. In order to effectively manage for resource impacts, it is important for managers to not only understand ecological aspects of their system but sociological aspects as well. The two papers presented in this thesis used integrated approaches to better understand the current level of resource impacts within the Bear Lake Road Corridor of Rocky Mountain National Park and to explore visitor perceptions of these impacts. The first paper used traditional monitoring and assessment techniques, as well as recently developed methodologies, to determine the current level of resource impacts …

Factors Affecting Gunnison Sage-Grouse (Centrocercus Minimus) Conservation In San Juan County, Utah, Phoebe R. Prather

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Due to loss of habitat, Gunnison sage-grouse (Centrocercus minimus) currently occupy 8.5% of their presumed historical range. One population survives in Utah, occurring in San Juan County. The Gunnison Sage-grouse Rangewide Conservation Plan and the San Juan County Gunnison Sage-grouse Conservation Plan recommended management strategies to address identified conservation threats to the Utah population. I addressed three conservation strategies identified in the plans: 1) creation and enhancement of brood-rearing areas; 2) assessment of habitat conditions within the Gunnison Sage-grouse Conservation Area; and 3) prevention or reduction of perching events by avian predators on distribution line power poles.

From 2007-2009, I …

Effect Of Mica Content On Surface Infiltration Of Soils In Northwestern Kern County, California, Steven Keyes Stakland

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A soils infiltration rate (IR) is the measured rate that soil is able to absorb water, either from precipitation or irrigation. A low IR can cause damage to crops if the necessary amount of water cannot penetrate to the plant roots in the time needed. The damage can be common in permanent plantings such as almond and pistachio orchards where regular tillage is avoided. This indicates a physical aspect to the problem because tillage increases IR. However, there is also an electrochemical side to infiltration problems because certain calcium surfactant treatments can increase IR. Various other methods have been used …

Pervasive Thermal Consequences Of Stream-Lake Interactions In Small Rocky Mountain Watersheds, Usa, Jessica D. Garrett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Limnologists and stream ecologists acknowledge the fundamental importance of temperature for regulating many ecological, biological, chemical, and physical processes. I investigated how water temperatures were affected by hydrologic linkages between streams and lakes at various positions along surface water networks throughout several headwater basins in the Sawtooth and White Cloud Mountains of Idaho (USA). Temperatures of streams and lakes were measured for up to 27 months in seven 6 – 41 km² watersheds, with a range of lake influence. When they were ice-free, warming in lakes resulted in dramatically warmer temperatures at lake outflows compared to inflow streams (midsummer …

Spatial Light Dilution As A Technique For Conversion Of Solar Energy To Algal Biomass, Daniel J. Dye

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A photobioreactor has been designed and developed to efficiently utilize solar irradiance through spatial dilution of sunlight. The concept of spatial light dilution is simple: incident sunlight is spread over a large surface area, thus reducing the photon flux density of the light. The implementation of this technique, however, is difficult. The reactor described within uses a new approach to spatial light dilution, utilizing recently-developed optical components to diffuse concentrated sunlight inside an algae culture. Preliminary productivity tests indicate a 2-3 fold increase in productivity per unit aperture (sunlight collection area) over a control reactor with direct-sunlight. Aperture productivity of …

Kinetic, Mechanistic, And Structural Investigation Of Features Controlling Stereoselectivity Of (R)- And (S)-Hydroxypropyl Com Dehydrogenases From Xanthobacter Autrophicus Strain Py2, Dariusz Adam Sliwa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Enantiopure alcohols are valuable intermediates in fine organic synthesis, in particular for preparation of biologically active compounds. The necessity of preparing single enantiomer drugs in an optically pure form has triggered much research, especially in the pharmaceutical industry. The biocatalytical production of chiral alcohols by alcohol dehydrogenase enzymes is characterized by the asymmetric reduction of the corresponding ketones, usually with high degree of stereoselectivity. The commercial value of the enzymes as stereoselective biocatalysts has been a significant driving force in understanding features that control their mechanism of catalysis and stereoselectivity. This work focuses on two enantiocomplementary dehydrogenase enzymes ((R …

Learning-Based Fusion For Data Deduplication: A Robust And Automated Solution, Jared Dinerstein

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis presents two deduplication techniques that overcome the following critical and long-standing weaknesses of rule-based deduplication: (1) traditional rule-based deduplication requires significant manual tuning of the individual rules, including the selection of appropriate thresholds; (2) the accuracy of rule-based deduplication degrades when there are missing data values, significantly reducing the efficacy of the expert-defined deduplication rules.

The first technique is a novel rule-level match-score fusion algorithm that employs kernel-machine-based learning to discover the decision threshold for the overall system automatically. The second is a novel clue-level match-score fusion algorithm that addresses both Problem 1 and 2. This unique solution …

Novel Approaches To Image Segmentation Based On Neutrosophic Logic, Ming Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Neutrosophy studies the origin, nature, scope of neutralities, and their interactions with different ideational spectra. It is a new philosophy that extends fuzzy logic and is the basis of neutrosophic logic, neutrosophic probability, neutrosophic set theory, and neutrosophic statistics.

Because the world is full of indeterminacy, the imperfection of knowledge that a human receives/observes from the external world also causes imprecision. Neutrosophy introduces a new concept , which is the representation of indeterminacy. However, this theory is mostly discussed in physiology and mathematics. Thus, applications to prove this theory can solve real problems are needed.

Image segmentation is the first …

Architecture, Modeling, And Analysis Of A Plasma Impedance Probe, Magathi Jayaram

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Variations in ionospheric plasma density can cause large amplitude and phase changes in the radio waves passing through this region. Ionospheric weather can have detrimental effects on several communication systems, including radars, navigation systems such as the Global Positioning Sytem (GPS), and high-frequency communications. As a result, creating models of the ionospheric density is of paramount interest to scientists working in the field of satellite communication.

Numerous empirical and theoretical models have been developed to study the upper atmosphere climatology and weather. Multiple measurements of plasma density over a region are of marked importance while creating these models. The lack …

An Evolutionary Approach To Optimization Of Compound Stock Trading Indicators Used To Confirm Buy Signals, Allan W. Teeples

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis examines the application of genetic algorithms to the optimization of a composite set of technical indicator filters to confirm or reject buy signals in stock trading, based on probabilistic values derived from historical data. The simplicity of the design, which gives each filter within the composite filter the ability to act independently of the other filters, is outlined, and the cumulative indirect effect each filter has on all the others is discussed. This system is contrasted with the complexity of systems from previous research that attempt to merge several indicator filters together by giving each one a weight …

Ab Initio Search For Novel Bxhy Building Blocks With Potential For Hydrogen Storage, Jared K. Olson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

On-board hydrogen storage presents a challenging barrier to the use of hydrogen as an energy source because the performance of current storage materials falls short of platform requirements. Because boron is one of the lightest chemical elements that can form strong covalent bonds with hydrogen, it provides an excellent opportunity to design new lightweight materials on the basis of novel boron hydride building blocks. Realizing this potential requires an understanding of the electronic structure, chemical bonding, and stability of neutral and anionic B_xH_y clusters with variable stoichiometry. While a large number of boron hydride compounds are known, …

Residential Landscape Water Check Programs: Exploring A Conservation Tool, Diana T. Glenn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In response to drought and regional growth in the arid western United States, urban water demand management is increasingly important. Single family residences use approximately 60% of their water consumption to irrigate landscapes often in excess of plant water requirements. This study utilized a quasi-experimental design to investigate outdoor water consumption and assess the effectiveness of a landscape water check conservation program. Study objectives included describing a contextualized landscape system to reveal variables influencing water use, identifying better ways to evaluate landscape water use, and more effectively targeting and delivering water conservation programs.

The study was conducted during the 2004 …

Interclonal Variation Of Primary And Secondary Chemistry In Western Quaking Aspen And Its Influence On Ungulate Selection, Damon A. Winter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Quaking aspen (Populus tremuloides) clones within close proximity to one another can exhibit drastically different levels of browsing by ungulates. The objectives of this study were to (1) determine interclonal differences in plant chemistry between adjacent clones exhibiting different degrees of herbivory which may influence the browsing behavior and patterns of ungulates, and (2) determine if correlation exists in the levels of salicortin and tremulacin between current year's suckers and current year's growth on older trees. This second objective was meant to indicate a protocol for land managers for identifying clones meriting increased protection from herbivory after treatment …

Spatial Epidemiology Of Birth Defects In The United States And The State Of Utah Using Geographic Information Systems And Spatial Statistics, Samson Y. Gebreab

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Oral clefts are the most common form of birth defects in the United States (US) and the State of Utah has among the highest prevalence of oral clefts in the nation. The overall objective of this dissertation was to examine the spatial distribution of oral clefts and their linkage with a broad range of demographic, behavioral, social, economic, and environmental risk factors through the application of Geographic Information Systems (GIS) and spatial statistics. Using innovative linked micromaps plots, we investigated the geographic patterns of oral clefts occurrence from 1998 to 2002 and their relationships with maternal smoking rates and proportion …

Analysis Of Ammonia And Volatile Organic Amine Emissions In A Confined Poultry Facility, Hanh Hong Thi Dinh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The National Air Emission Monitoring Study (NAEMS) project was funded by the Agricultural Air Research Council (AARC) to evaluate agricultural emissions nationwide. Utah State University (USU) is conducting a parallel study on agricultural emissions at a Cache Valley poultry facility. As part of this parallel study, samples of animal feed, eggs and animal waste were collected weekly from three manure barns (designated: manure barn, barn 4 - manure belt and barn 5 - high rise) from May 2008 to November 2009.

These samples were analyzed to determine ammonia content, total Kjeldahl nitrogen content and ammonia emission. The yearly average calculated …

An Exploratory Study On Issues And Challenges Of Agile Software Development With Scrum, Juyun Joey Cho

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this dissertation was to explore critical issues and challenges that might arise in agile software development processes with Scrum. It also sought to provide management guidelines to help organizations avoid and overcome barriers in adopting the Scrum method as a future software development method. A qualitative research method design was used to capture the knowledge of practitioners and scrutinize the Scrum software development process in its natural settings. An in-depth case study was conducted in two organizations where the Scrum method was fully integrated in every aspect of two organizations' software development processes. One organization provides large-scale …

Expanding The Horizons Of Educational Pair Programming: A Methodological Review Of Pair Programming In Computer Science Education Research, Keith B. Rimington

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Educators and researchers continue to explore the benefits, real or imagined, of implementing pair programming as part of the computer science pedagogy. Current reviews of computer science educational research practices do not focus on educational pair programming. This thesis presents a review of the research methods used in recent educational pair programming research. The primary purpose of this review is to inform the ongoing dialogue about and to provide evidence-based recommendations for improving educational pair programming research.

Replicating the design of a previous computer science education methodological review, this study inspected a sample of 108 articles from a population of …

Applying Information Visualization To Computer Security Applications, Robert Bruce Whitaker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis presents two phases of research in applying visualization to network security challenges. The first phase included discovering the most useful and powerful features in existing computer security visualizations and incorporating them into the AdviseAid visualization platform, an existing software package. The incorporation of such a complete feature set required novel resolution of software engineering, human factors, and computer graphics issues. We also designed additional novel features, such as plugin interfaces, allowing for rapid prototyping and experimentation with novel visualization features and capabilities. The second phase of the research focused on the development of novel visualization techniques themselves. These …