Physical Sciences and Mathematics Commons^™

The Balancing Act: Ecological Interventions And Decision Tradeoffs To Preserve Wilderness Character, Lucy A. Lieberman

Graduate Student Theses, Dissertations, & Professional Papers

Global climate change, land use intensification and increasing development are impacting federal wildernesses in new and unprecedented ways. Ecological restoration is one tool that that wilderness managers are using to combat degradation, though the decision to intervene in wilderness is complicated by the Wilderness Act’s legal mandate to preserve wilderness character and demonstrate managerial restraint. The purpose of this study is to document a baseline of ecological interventions that have occurred in the NWPS over the last five years, and to understand how wilderness managers make decisions related to ecological interventions. I sent a quantitative survey to over five hundred …

The Influence Of Tree Height On Lidar’S Ability To Accurately Characterize Forest Structure And Spatial Pattern Across Reference Landscapes, Haley L. Wiggins

Graduate Student Theses, Dissertations, & Professional Papers

Successful restoration of degraded forest landscapes requires reference models that adequately capture structural heterogeneity at multiple spatial scales. Field-based methods for assessing variation in forest structure are costly and inherently suffer from limited replication and spatial coverage. LiDAR is a more cost-effective approach for generating landscape-scale data, but it has a limited ability to detect understory trees. Increased understanding of appropriate height cut-offs for trees to be reliably included in LiDAR-based analysis could improve applications of LiDAR to assessments of landscape-scale forest structure. Toward that end, I investigated the effect of varying tree-height criterion (minimum height cutoffs of 6, 9, …

Response Of Amphibian And Invertebrate Communities To Wetland Mitigation In The Greater Yellowstone Ecosystem, Leah K. Swartz

Graduate Student Theses, Dissertations, & Professional Papers

Wetlands play a critical role in supporting freshwater biodiversity and ecosystem services, but human activities have resulted in large-scale loss and degradation of these habitats across the globe. To offset the decline of wetland area, mitigation wetlands are now frequently constructed, but their ability to replace the functions of natural habitats, including providing habitat for native fauna, remains uncertain. A recent highway reconstruction project in northwestern Wyoming caused impacts to and the destruction of multiple natural wetlands. To mitigate this loss, new wetlands were constructed along the highway corridor. To evaluate the performance of these created wetlands relative to reference …

Environmental Hazard Identification, Assessment And Control For A Sustainable Maritime Transportation System, Lizzette Marie Pérez Lespier

Doctoral Dissertations

"A demand exists to contribute towards the widening awareness of the need for sustainable maritime development and for coordinated maritime policies worldwide. Maritime shipping is considered the most eco-efficient mean of transportation and yet, is responsible for negative environmental impacts.

This dissertation focuses on developing data-driven decision support tools to evaluate the sustainable performance of MTS by focusing on the elements of the MTS that place stress on the environment. The first research contribution is a System Dynamics simulation model that examines the MTS resiliency after an extreme event and determines the sequence needed to restore the ocean-going port to …

Electron Impact Excitation-Ionization Of Molecules, Esam Abobakr A. Ali

Doctoral Dissertations

"In the last few decades, the study of atomic collisions by electron-impact has made significant advances. The most difficult case to study is electron impact ionization of molecules for which many approximations have to be made and the validity of these approximations can only be checked by comparing with experiment.

In this thesis, I have examined the Molecular three-body distorted wave (M3DW) or Molecular four-body distorted wave (M4DW) approximations for electron-impact ionization. These models use a fully quantum mechanical approach where all particles are treated quantum mechanically and the post collision interaction (PCI) is treated to all orders of perturbation. …

Characterizations Of Families Of Rectangular, Finite Impulse Response, Para-Unitary Systems, Daniel Alpay, Palle Jorgensen, Izchak Lewkowicz

Mathematics, Physics, and Computer Science Faculty Articles and Research

We here study Finite Impulse Response (FIR) rectangular, not necessarily causal, systems which are (para)-unitary on the unit circle (=the class U). First, we offer three characterizations of these systems. Then, introduce a description of all FIRs in U, as copies of a real polytope, parametrized by the dimensions and the McMillan degree of the FIRs.

Finally, we present six simple ways (along with their combinations) to construct, from any FIR, a large family of FIRs, of various dimensions and McMillan degrees, so that whenever the original system is in U, so is the whole family.

A key role is …

Genetic Algorithms As A Viable Method Of Obtaining Branch Coverage, Jason Ross Frier

UNF Graduate Theses and Dissertations

Finding a way to automate the generation of test data is a crucial aspect of software testing. Testing comprises 50% of all software development costs [Korel90]. Finding a way to automate testing would greatly reduce cost and labor involved in the task of software testing. One of the ways to automate software testing is to automate the generation of test data inputs. For example, in statement coverage, creating test cases that will cover all of the conditions required when testing that program would be costly and time-consuming if undertaken manually. Therefore, a way must be found that allows the automation …

Social Networks Influence Analysis, Doaa Gamal

UNF Graduate Theses and Dissertations

Pew Research Center estimates that as of 2014, 74% of the Internet Users used social media, i.e., more than 2.4 billion users. With the growing popularity of social media where Internet users exchange their opinions on many things including their daily life encounters, it is not surprising that many organizations are interested in learning what users say about their products and services. To be able to play a proactive role in steering what user’s say, many organizations have engaged in efforts aiming at identifying efficient ways of marketing certain products and services, and making sure user reviews are somewhat favorable. …

Security Analytics: Using Deep Learning To Detect Cyber Attacks, Glenn M. Lambert Ii

UNF Graduate Theses and Dissertations

Security attacks are becoming more prevalent as cyber attackers exploit system vulnerabilities for financial gain. The resulting loss of revenue and reputation can have deleterious effects on governments and businesses alike. Signature recognition and anomaly detection are the most common security detection techniques in use today. These techniques provide a strong defense. However, they fall short of detecting complicated or sophisticated attacks. Recent literature suggests using security analytics to differentiate between normal and malicious user activities.

The goal of this research is to develop a repeatable process to detect cyber attacks that is fast, accurate, comprehensive, and scalable. A model …

Extracting A Relational Database Schema From A Document Database, Jared Thomas Wheeler

UNF Graduate Theses and Dissertations

As NoSQL databases become increasingly used, more methodologies emerge for migrating from relational databases to NoSQL databases. Meanwhile, there is a lack of methodologies that assist in migration in the opposite direction, from NoSQL to relational. As software is being iterated upon, use cases may change. A system which was originally developed with a NoSQL database may accrue needs which require Atomic, Consistency, Isolation, and Durability (ACID) features that NoSQL systems lack, such as consistency across nodes or consistency across re-used domain objects. Shifting requirements could result in the system being changed to utilize a relational database. While there are …

Agricultural Adaptation To Climate Change: How Risk Influences Decision-Making, Brandon Araujo

UNF Graduate Theses and Dissertations

Climate change is currently threatening the livelihoods of farmers in developing countries. Psychological models have been developed to identify factors associated with adapting to climate change; however, little work has investigated the role of farmers’ risk attitudes in these models. We assessed perceptions of adaptation cost and adaptation intentions for five drought- specific adaptive behaviors among 550 farmers from 12 villages in the dry zone of Sri Lanka, as well as their attitudes toward risk. Results suggest that perceived adaptation cost and risk attitude are negatively associated with adaptation intentions. The conditional effect of adaptation cost on adaptation intention as …

Designing 2d Interfaces For 3d Gesture Retrieval Utilizing Deep Learning, Spencer Southard

UNF Graduate Theses and Dissertations

Gesture retrieval can be defined as the process of retrieving the correct meaning of the hand movement from a pre-assembled gesture dataset. The purpose of the research discussed here is to design and implement a gesture interface system that facilitates retrieval for an American Sign Language gesture set using a mobile device. The principal challenge discussed here will be the normalization of 2D gestures generated from the mobile device interface and the 3D gestures captured from video samples into a common data structure that can be utilized by deep learning networks. This thesis covers convolutional neural networks and auto encoders …

A Survey Of Butterfly Diagrams For Knots And Links, Mark Ronnenberg

Dissertations and Theses @ UNI

A “butterfly diagram” is a representation of a knot as a kind of graph on the sphere. This generalization of Thurston’s construction of the Borromean rings was introduced by Hilden, Montesinos, Tejada, and Toro to study the bridge number of knots. In this paper, we study various properties of butterfly diagrams for knots and links. We prove basic some combinatorial results about butterflies and explore properties of butterflies for classes of links, especially torus links. The Wirtinger presentation for the knot group will be adapted to butterfly diagrams, and we translate the Reidemeister moves for knot diagrams into so-called “butterfly …

Quantum Inspired Symmetries In Laser Engineering, Mohammad Hosain Teimourpour

Dissertations, Master's Theses and Master's Reports

In this thesis, quantum inspired symmetries including Parity-Time (PT) symmetry and Supersymmetry (SUSY) have been studied in the context of non-Hermitian engineered laser systems. This thesis starts with a short review of semiconductor lasers theory in second chapter, followed by an introduction to quantum inspired symmetries: PT symmetry and SUSY in optics and photonics in chapter three.

In chapter four, we have studied the robustness and mode selectivity in PT symmetric lasers. We investigate two important aspects of PT symmetric photonic molecule lasers, namely the robustness of their single longitudinal mode operation against instabilities triggered by spectral hole burning effects, …

Modeling And Simulation Of The Peristaltic Flow Of Newtonian And Non-Newtonian Fluids With Application To The Human Body, Samer Alokaily

Dissertations, Master's Theses and Master's Reports

Computational models are developed to investigate peristaltic motion in the human gastro-intestinal tract. The peristaltic motion is simulated by means of traveling waves which deform the boundary of the tubes. An axisymmetric tube of uniform diameter is used to model the small intestines, and an axisymmetric conical geometry is developed to model the lower part of the human stomach. The conical geometry represents a simplification of the more complicated three-dimensional models of the human stomach that have been used in other studies. Also, they seeks to reduce computational costs and circumvent difficulties of mesh generation. The computations are performed within …

Search For High-Energy Gamma Rays In The Northern Fermi Bubble Region With The Hawc Observatory, Hugo Alberto Ayala Solares

Dissertations, Master's Theses and Master's Reports

Gamma-ray astronomy is the study of very energetic photons, from E = m_ec² = 0.5x10⁶ eV to > 10²⁰eV. Due to the large span of the energy range, the field focuses on non-thermal processes that include the acceleration and propagation of relativistic particles, which can be found in extreme environments such as pulsars, supernova remnants, molecular clouds, black holes, etc.

The High Altitude Water Cherenkov (HAWC) observatory is an instrument designed for the study of gamma rays in the energy range of 100 GeV to 100 TeV. Using data from the HAWC observatory, a study …

Distribution Of Permutation Statistics Across Pattern Avoidance Classes, And The Search For A Denert-Associated Condition Equivalent To Pattern Avoidance, Joshua Thomas Agustin Davies

Dissertations, Master's Theses and Master's Reports

We begin with a discussion of the symmetricity of $\maj$ over $\des$ in pattern avoidance classes, and its relationship to $\maj$-Wilf equivalence. From this, we explore the distribution of permutation statistics across pattern avoidance for patterns of length 3 and 4.

We then begin discussion of Han's bijection, a bijection on permutations which sends the major index to Denert's statistic and the descent number to the (strong) excedance number. We show the existence of several infinite families of fixed points for Han's bijection.

Finally, we discuss the image of pattern avoidance classes under Han's bijection, for the purpose of finding …

Distance Perception In Virtual Environment Through Head-Mounted Displays, Bochao Li

Dissertations, Master's Theses and Master's Reports

Head-mounted displays (HMDs) are popular and affordable wearable display devices which facilitate immersive and interactive viewing experience. Numerous studies have reported that people typically underestimate distances in HMDs.

This dissertation describes a series of research experiments that examined the influence of FOV and peripheral vision on distance perception in HMDs and attempts to provide useful information to HMD manufacturers and software developers to improve perceptual performance of HMD-based virtual environments.

This document is divided into two main parts. The first part describes two experiments that examined distance judgments in Oculus Rift HMDs. Unlike numerous studies found significant distance compression, our …

Investigating The Utility Of Rapid Assessment Process For Environmental Development Work Of Peace Corps Master’S International Students, Mariah Maggio

Dissertations, Master's Theses and Master's Reports

Peace Corps Master’s International (PCMI) students engage in international development when they assume the role of Volunteer and graduate researcher. Michigan Technological University had the largest PCMI program in the country, with many Volunteer assignments involving environmental problem solving opportunities. Unfortunately some PCMI students have experienced “failed projects,” something not un-common to international development approaches. This research design supports institutional interdisciplinary efforts aimed at preparing PCMI students to engage in productive community development that avoids historic pitfalls of international development efforts. In order to contribute to this effort, the Rapid Assessment Process (RAP) approach was identified as a potential tool …

Numerical Simulation Of Viscoelastic Multiphase Flows Using An Improved Two-Phase Flow Solver, Olabanji Shonibare

Dissertations, Master's Theses and Master's Reports

The production of uniformly-sized droplets has numerous applications in various fields including the biotechnology and chemical industries. For example, in the separation of mixtures based on their relative absorbency, an optimal arrangement of monodispersed droplets in columns is desired for an effective separation. However, very few numerical studies on the formation of viscoelastic droplets via cross-flow shear are available, none of which have considered the case when the flow of the continuous phase is Couette. In this work, a new solver capable of automatic mesh refinement is developed for the OpenFOAM CFD toolbox to solve viscoelastic two-phase flow problems. The …

Improving Everyday Computing Tasks With Head-Mounted Displays, James Walker

Dissertations, Master's Theses and Master's Reports

The proliferation of consumer-affordable head-mounted displays (HMDs) has brought a rash of entertainment applications for this burgeoning technology, but relatively little research has been devoted to exploring its potential home and office productivity applications. Can the unique characteristics of HMDs be leveraged to improve users’ ability to perform everyday computing tasks? My work strives to explore this question.

One significant obstacle to using HMDs for everyday tasks is the fact that the real world is occluded while wearing them. Physical keyboards remain the most performant devices for text input, yet using a physical keyboard is difficult when the user can’t …

Characterization Of Ecological Water Stress In The U.S. Great Lakes Region Using A Geospatial Modeling Approach, Sara Alian

Dissertations, Master's Theses and Master's Reports

Anthropocentric water resources management affects aquatic habitats by changing streamflow regime. Understanding the impacts of water withdrawal from different sources and consumption by various economic sectors at different spatial and temporal scales is key to characterizing ecologically harmful streamflow disturbances. To this end, we developed a generic, integrative framework to characterize catchment scale water stress at annual and monthly time scales. The framework accounts for spatially cumulative consumptive and non-consumptive use impacts and associated changes in flow due to depletion and return flow along the stream network. Application of the framework to the U.S. Great Lakes Region indicates that a …

The Effects Of Early Pruning On The Near-Ground Branch Density Of Four Live Fencing Species, Aric Devens

Dissertations, Master's Theses and Master's Reports

Crop losses in home gardens greatly impact the wellbeing of rural West African families. Herbivory by migratory or local livestock represents a significant source of crop loss. Live-fencing gardens with thorny hedges is a low-cost and sustainable strategy for reducing losses due to herbivory. However, guidance on the establishment of thorny hedges is inconsistent, poorly publicized, and often anecdotal. Therefore, this study evaluated the effects of three early pruning treatments on near-ground branch density of four thorny species: Vachellia nilotica, Senegalia laeta, Senegalia mellifera, and Prosopis juliflora. Physical measurements and photographic data indicated that after one growing season, V. …

Distance Magic-Type And Distance Antimagic-Type Labelings Of Graphs, Bryan Freyberg

Dissertations, Master's Theses and Master's Reports

Generally speaking, a distance magic-type labeling of a graph G of order n is a bijection f from the vertex set of the graph to the first n natural numbers or to the elements of a group of order n, with the property that the weight of each vertex is the same. The weight of a vertex x is defined as the sum (or appropriate group operation) of all the labels of vertices adjacent to x. If instead we require that all weights differ, then we refer to the labeling as a distance antimagic-type labeling. This idea can be generalized …

Gamma/Hadron Separation For The Hawc Observatory, Michael J. Gerhardt

Dissertations, Master's Theses and Master's Reports

The High-Altitude Water Cherenkov (HAWC) Observatory is a gamma-ray observatory sensitive to gamma rays from 100 GeV to 100 TeV with an instantaneous field of view of ~2 sr. It is located on the Sierra Negra plateau in Mexico at an elevation of 4,100 m and began full operation in March 2015. The purpose of the detector is to study relativistic particles that are produced by interstellar and intergalactic objects such as: pulsars, supernova remnants, molecular clouds, black holes and more. To achieve optimal angular resolution, energy reconstruction and cosmic ray background suppression for the extensive air showers detected by …

Magnetic Petrophysics Of The Vulcan Iron Formation (Michigan, Usa), Matthew Laird

Dissertations, Master's Theses and Master's Reports

A detailed investigation of magnetic properties of the iron-bearing Traders and Curry members of the ~1.88 Ga Vulcan Iron Formation (Michigan’s eastern Upper Peninsula) was conducted using natural remanent magnetization, low-field magnetic susceptibility, anisotropy of magnetic susceptibility, thermomagnetic and magnetic hysteresis, and first-order reversal curve analyses. A set of samples were also investigated using electron scanning microscopy and energy dispersive spectrometry. Contrary to previously accepted views, our results indicate that the Traders and Curry members have substantially different properties. The older Traders member is a typical banded iron formation characterized by a higher relative amount of magnetite and stronger magnetic …

Multi-Modal And Short-Range Transmission Loss In Ice-Covered, Near-Shore Arctic Waters, Miles B. Penhale

Dissertations, Master's Theses and Master's Reports

In the past century, extensive research has been done regarding the sound propagation in arctic ice sheets. The majority of this research has focused on low frequency propagation over long distances. One of the most commonly used excitation methods for air-ice-water layers has been explosives. However, environmental regulation has become more stringent, disallowing the use of almost all explosive excitation types. Due to changing climate conditions in these environments, new experimentation is warranted to determine sound propagation characteristics in, through, and under thin ice sheets, in shallow water, over short distances. In April, 2016 several experiments were conducted approximately 2 …

Developing A Gis Tool For Infinite Slope Stability Analysis (Gis-Tissa), Jonathon Sanders

Dissertations, Master's Theses and Master's Reports

The Probabilistic Infinite Slope Analysis model (PISA-m) is a widely used computer program that uses infinite slope equations to calculate the spatially varying Factor of Safety of slopes. ESRI’s ArcGIS software and accompanying geoprocessing tools have become a mainstay in spatial data processing, and received full support for Python with the release of version 10. With many of the geoprocessing tools now available as a Python function, the software can be used for physics-based spatial landslide hazard analysis. A model that mimics PISA-m and its processing of normally distributed soil properties was created using the Python utility as a tool …

Analysis Of Data From A Study To Identify Potential Biomarkers To Indicate Renal Injury, Mitchell D. Tahtinen

Dissertations, Master's Theses and Master's Reports

Ureteropelvic junction obstruction is a disease in which flow from the kidney to the bladder is obstructed for extended periods of time causing irreversible damage to the kidney. Current tests to detect kidney damage caused by obstruction are not effective until significant damage occurs. The purpose of this report is to identify a panel of biomarkers in urine to detect kidney damage earlier by analyzing data collected from a two-part study. Currently, two established urinary biomarkers to indicate kidney damage are NGAL and KIM-1. Biomarkers of interest in this study are CD13, CD10, and CD26. Results from the linear mixed …

Rock Magnetic Investigation Of The Michigan Basin Soils And Sediments Overlying The Oil-Bearing Silurian Pinnacle Reefs, Jake Tresnak

Dissertations, Master's Theses and Master's Reports

A relationship between the hydrocarbon migration and magnetic properties of near-surface sediments was investigated from several hundreds of samples collected over the hydrocarbon-bearing Silurian pinnacle reef belt of the Michigan Basin. The collected samples were investigated using several rock magnetic methods and optical microscopy. The investigation has not revealed a straightforward relationship between the magnetic susceptibility and hydrocarbon reservoirs within the reef belt; both anomalously high and low susceptibility values were observed. The elevated values are associated with newly formed magnetite in the form of spheroidal grains produced by hydrocarbon-related diagenesis while the extremely low susceptibilities may reflect dissolution of …