Digital Commons Network^™

Development, Validation, And Utilization, Of A Long-Term Nearshore Synthetic Wave Record, Sergio A. Pena

UNF Graduate Theses and Dissertations

The need for a consistent and accurate production of long-term nearshore wave record is discussed. With multiple decades of offshore hindcasts and long, continuous data sets available, it is possible to create a nearshore synthetic wave record. The Brevard County coastline offers an area with a high quality 62-year long offshore hindcast, as well as an 11-year long and nearly continuous high-resolution nearshore wave record to compare with model performance. This thesis presents the steps in the development and performance of the synthetic nearshore wave record produced. A novel approach was used to compare, validate and calibrate this type of …

Investigating The Effects Of Rainfall On Traffic Operations On Florida Freeways, Lucia Andrew

UNF Graduate Theses and Dissertations

Rainfall affects the performance of traffic operations and endangers safety. A common and conventional method (rain gauges) for rainfall measurements mostly provide precipitation records in hourly and 15-minute intervals. However, reliability, continuity, and wide area coverage pose challenges with this data collection method. There is also a greater likelihood for data misrepresentation in areas where short duration rainfall is predominant, i.e., reported values may not reflect the actual equivalent rainfall intensity during subintervals over the entire reporting period. With recent weather and climate patterns increasing in severity, there is a need for a more effective and reliable way of measuring …

Hedonic Coalition Formation For Task Allocation With Heterogeneous Robots, Emily Czarnecki

UNF Graduate Theses and Dissertations

Tasks in the real world are complex in nature and often require multiple robots to collaborate in order to be accomplished. However, multiple robots with the same set of sensors working together might not be the optimal solution. In many cases a task might require different sensory inputs and outputs. However, allocating a large variety of sensors on each robot is not a cost-effective solution. As such, robots with different attributes must be considered. In this thesis we study the coalition formation problem for task allocation with multiple heterogeneous (equipped with a different set of sensors) robots. The proposed solution …

A Study On Erosion Resistance For Microbially Induced Calcite Treated Beach Sand, Abigail Chek

UNF Graduate Theses and Dissertations

Microbial induced calcite precipitation (MICP) was used to treat several sandboxes filled with naturally occurring beach sand collected from Atlantic Beach, FL. Unlike most previous MICP studies, a surface-spray technique was used to treat these sandboxes where relatively high-concentration bacteria solution and high concentration calcium chloride/urea solutions were applied directly to the boxes’ surfaces. Several different treatment combinations were tested whereby bacterial optical density, bacteria/urea/calcium chloride volume relative to void space, and bacteria/urea/calcium chloride ratio were manipulated. Treated sandboxes were tested for erodibility using a pocket erodometer and for calcification using a wash method. In addition, sandboxes were dissected after …

An Analysis Of Hydroacoustic Transmission Loss Associated With Marine Pile Driving, Jonathan Paul Berube

UNF Graduate Theses and Dissertations

There has been a growing concern in recent years about the effects of anthropogenic noise due to marine pile driving on underwater wildlife. Current guidelines for mitigating hydroacoustic effects associated with these events are based upon relatively simple transmission loss formulations. The advantage to these guidelines is that computing transmission loss using their prescribed methods is not labor intensive, but their disadvantage is that they may not take all variables into account. Because of this, it may be possible to improve transmission loss computations. To better-characterize marine pile driving sound transmission loss, a unique in-water instrumentation system was developed. This …

Evaluating The Performance Of Cooperative Merging Assistance System For Aging Drivers, Flavius Matata

UNF Graduate Theses and Dissertations

Freeway merging maneuvers demand considerable attention by drivers and are among the more complex operations drivers must perform on freeways. Aging drivers, a growing population in the United States, face added challenges when merging. This study utilized Vissim models created in a previous study that modeled the behavior of aging drivers during freeway merging. An algorithm for Cooperative Merging Assistance System (CMAS) that utilizes Connected Vehicle (CV) technology was developed in this study. The Vissim models were created for two interchanges on I-75 in Fort Myers, Florida, each with different geometric characteristics. Acceleration lane lengths of 1000ft and 1500ft were …

Evaluating Mobility And Safety Benefits Of Freeway Service Patrols: A Case Study Of Florida's Road Rangers, Jimoku H. Salum

UNF Graduate Theses and Dissertations

The Florida’s Road Rangers monitor the freeways for incidents to minimize their adverse impacts on traffic. The objectives of this study were to evaluate the extent to which Road Rangers reduce incident clearance duration (ICD), incident-induced traffic delays (IITDs) and secondary crashes (SCs).

Since ICD distributions are often right-skewed, the study applied quantile regression to relate ICD to influencing factors. Data skewed to the right is usually a result of lower bounds in a data set being extremely low relative to the rest of the data. Data from 28,000 incidents that occurred on freeways in Jacksonville, Florida were analyzed. Of …

Simulation Exploration Of The Potential Of Connected Vehicles In Mitigating Secondary Crashes, Mike Alvin Soloka

UNF Graduate Theses and Dissertations

Secondary crashes (SCs) on freeways are a major concern for traffic incident management systems. Studies have shown that their occurrence is significant and can lead to deterioration of traffic flow conditions on freeways in addition to injury and fatalities, albeit their magnitudes are relatively low when compared to primary crashes. Due to the limited nature of crash data in analyzing freeway SCs, surrogate measures provide an alternative for safety analysis for freeway analysis using conflict analysis. Connected Vehicles (CVs) have seen compelling technological advancements since the concept was introduced in the 1990s. In recent years, CVs have emerged as a …

The Use Of Real-Time Connected Vehicles And Here Data In Developing An Automated Freeway Incident Detection Algorithm, Hendry Nyanza Imani

UNF Graduate Theses and Dissertations

Traffic incidents cause severe problems on roadways. About 6.3 million highway crashes are reported annually only in the United States, among which more than 32,000 are fatal crashes. Reducing the risk of traffic incidents is key to effective traffic incident management (TIM). Quick detection of unexpected traffic incidents on roadways contribute to quick clearance and hence improve safety. Existing techniques for the detection of freeway incidents are not reliable.

This study focuses on exploring the potential of emerging connected vehicles (CV) technology in automated freeway incident detection in the mixed traffic environment. The study aims at developing an automated freeway …

Exploring Applicability Of Blockchain To Enhance Single Sign-On (Sso) Systems, Samuel Matloob

UNF Graduate Theses and Dissertations

Single-Sign-On (SSO) systems usage has been on the rise exponentially. One of the major benefits of having an SSO system is to have a central authentication service, which other applications can use. However, SSO services are also prone to failure. If an SSO service becomes unavailable due to failure, every application that uses the SSO service become simultaneously inaccessible to users. The goal of this research is to explore a technique to mitigate the availability issue of the SSO by customizing its functionality, and distributing its data using blockchain technology over the network. The Blockchain data structure possesses inherent properties …

History Repeats Itself: Some New Faces Behind Sex Trafficking Are More Familiar Than You Think, Mary Graw Leary

Scholarly Articles

This Essay argues that the historical pattern of businesses that benefit directly or indirectly from the slave trade opposing efforts to end that sale of human beings is repeating itself today. Some tech companies and other members of the digital economy face a perverse motivation: they profit indirectly from online sex trafficking and risk decreased profits from a more regulated Internet. As such, they take on the same role of the cotton and textile merchants of the nineteenth century, arguing for legislative action that will continue to enable the trade and exploitation of human beings, thereby allowing them to retain …

New Correlation For Calculating Acentric Factor Of Petroleum 2 Fractions, Samir Khaled

Petroleum Engineering and Gas

A proper description of the physical properties of the petroleum fractions in hydrocarbon mixtures is 12 essential in performing reliable phase behavior calculations and compositional modeling studies. This 13 paper presents a comparison study among five different correlations used to calculate the acentric 14 factor of undefined petroleum fractions. A new correlation was developed for calculating the acentric 15 factor of undefined petroleum fractions, a function of no carbon atoms with an average error of 0.099 16 and a correlation coefficient of 0.998.

Impact Of Practical Education Network On Students And Teachers In The Ghanaian Junior High School Classroom, Jake Babb

Dissertations, Master's Theses and Master's Reports

The Ghanaian education system has a pervasive teacher-centered pedagogy, lack or absence of laboratory materials, poor-quality teacher training, and minimal support systems for teachers. Practical Education Network is an organization which addresses these problems by training science teachers through workshops about how to utilize locally-available, affordable materials in order to teach topics in the national curriculum in an inquiry-based manner. Three hundred and twenty-four students in six different Junior High Schools in the Greater Accra Region participated in a year-long, quasi-experimental study in order to test the impact that the PEN approach has on students' classroom environment, critical thinking skills, …

Mpc-Based Autonomous Driving Control With Localized Path Planning For Obstacle Avoidance And Navigating Signalized Intersections, Sai Rajeev Devaragudi

Dissertations, Master's Theses and Master's Reports

Connected and autonomous vehicles are becoming the major focus of research for the industry and academia in the automotive field. Many companies and research groups have demonstrated the advantages and the requirement of such technology to improve the energy efficiency of vehicles, decrease the number of crash and road accidents, and control emissions.

This research delves into improving the autonomy of self-driving vehicles by implementing localized path planning algorithms to introduce motion control for obstacle avoidance during uncertainties. Lateral path planning is implemented using the A* algorithm combined with piecewise Bezier curve generation which provides an optimum trajectory reference to …

A Critical Review Of Current Approaches And Practices In Computing Ethics Education, Sophia Farquhar

Dissertations, Master's Theses and Master's Reports

Recent scandals caused by the results of negligent, malicious, or shortsighted software development practices highlight the need for software developers to consider the ethical implications of their work. Computing ethics has historically been a marginalized area within computing disciplines, so educators in these disciplines do not have a common background for teaching the topic. Computing ethics education, although often a required part of coursework, can vary widely in the method of implementation from university to university.

In this report I summarize the insights I gained from interviewing four educators from three different institutions on their pedagogical approaches to computing ethics. …

Comparative Study And Design Of Economical Sound Intensity Probe, Karan Gundre

Dissertations, Master's Theses and Master's Reports

The theory of sound intensity measurement using the two-microphone method was first developed in the late 1970s. Even though the measurements were limited by the technology of the time, the theory was straight-forward and considerable attention was given to improving precision during testing or post-processing. With the development of modern equipment, however, the focus shifted to the apparatus. The commercial intensity probes available today have microphones that are already phase-matched. This eliminates the need for correction during or post-testing as a majority of the errors are minimized before any data is even collected. Although such intensity probes facilitate taking precise …

Improved Low-Frequency Impact Insulation Class Measurements Based On Comparison Techniques, Sunit Girdhar

Dissertations, Master's Theses and Master's Reports

In today’s world, noise pollution is growing as a major concern and it is becoming more and more difficult to find quiet places. But when the problem escalates to the extent that people are annoyed with loud noises even in their apartments, it becomes an alarming issue for engineers. Around the world, cities have defined some basic performance requirements for buildings, and isolation of residents from noise is one of the cardinal performance requirements. In the United States, building codes use the Impact Insulation Class (IIC) rating to characterize the performance of floor/ceiling assemblies. This method uses the response measured …

Hometracker: A Household Information Feedback System For Food/Energy/Water Metabolism, Nichole Mackey

Dissertations, Master's Theses and Master's Reports

The Food, Energy and Water Conscious (FEWCON) project seeks to understand how food, energy and water (FEW) as independent resources within households are connected. In the main study of the project, intervention messages that link household FEW consumption to equivalent climate consequences are pushed to the households. The goal of the FEWCON study is to determine potential intervention messages that influence household FEW consumption behavior.

A key component of the FEWCON study is a web application named HomeTracker (Household Metabolism Tracker) which collects FEW consumption data within households, then uses this data to select consumption-specific feedback to the homeowners. To …

Accessible Access Control: A Visualization System For Access Control Policy Management, Man Wang

Dissertations, Master's Theses and Master's Reports

Attacks on computers today present in many different forms, causing malfunction of operating systems, information leakage and loss of business and public trust. Access control is a technique that stands as the last line of protection restricting the access of users or processes to resources on computers. Throughout the years, many access control models have been implemented to accommodate security requirements under different circumstances. However, the learning of access control models and the management of access control policies are still challenging given its abstract nature, the lack of an environment for practice, and the intricacy of fulfilling complex security goals. …

High Order Bound-Preserving Discontinuous Galerkin Methods And Their Applications In Petroleum Engineering, Ziyao Xu

Dissertations, Master's Theses and Master's Reports

This report contains researches in the theory of high-order bound-preserving (BP) discontinuous Galerkin (DG) method and their applications in petroleum engineering. It contains both theoretical analysis and numerical experiments. The compressible miscible displacements and wormhole propagation problem, arising in petroleum engineering, is used to describe the evolution of the pressure and concentrations of different components of fluid in porous media. The important physical features of concentration and porosity include their boundedness between 0 and 1, as well as the monotone increasing for porosity in wormhole propagation model. How to keep these properties in the simulation is crucial to the robustness …

Community Solar Energy Programs: A Bright Spot For Just Energy Policy?, Emily Prehoda

Dissertations, Master's Theses and Master's Reports

Energy systems are complex, and this complexity requires diverse regulatory forms and strategies of management. Michigan’s energy system is situated within a multi-scalar governance structure reaching from national to local levels. As a result, the process of energy system decision-making can leave out smaller, remote communities and those without the economic, political, and knowledge capital necessary to engage in complex bureaucratic processes. These communities can become subject to high electricity prices and unreliable electrical service from long transmission and distribution lines, raising energy justice concerns. Additionally, resulting from utility regulatory practices, small remote communities are often not afforded the opportunity …

Paleomagnetic Investigation Of Igneous Rocks Deformed By The Keweenaw Fault In The Northwestern Keweenaw Peninsula., Daniel Trekas

Dissertations, Master's Theses and Master's Reports

One of the most prominent structural features associated with the ~1.1 Ga Midcontinent Rift (MCR) system is the >350 km long Keweenaw Fault that bisects the Keweenaw Peninsula, separating the MCR-related Portage Lake Volcanics (PLV) and the younger Jacobsville Sandstone (JS). The fault trend is NE-NNE over most of its length, but changes to an easterly direction along the shore of Bête Grise Bay near the end of the peninsula. Conventionally, the Keweenaw Fault has been considered to be a continuous reverse (dip-slip) fault formed by inversion of an original rift-bounding normal fault during the Grenville Orogeny. However, recent mapping …

Spatial And Temporal Distribution Of Hydrothermal Minerals And Sources Of Hydrothermal Fluids Inferred From Light Stable Isotopes, Keweenaw Peninsula Native Copper District, Michigan, Thomas Bodden

Dissertations, Master's Theses and Master's Reports

Hydrothermal native copper deposits are hosted by Mesoproterozoic Midcontinent Rift-filling volcanic and sedimentary rocks in Michigan’s Keweenaw Peninsula. The genesis of the native copper deposits has been a point of interest since their discovery. Native copper and associated mineral assemblages vary temporally and spatially. A refined mineral paragenesis is presented and used as the basis to spatially compare mineral assemblages as it is essential that spatial comparison involve only minerals that are temporally/genetically, related to each other. The main-stage minerals associated with precipitation of native copper are spatially zoned. The higher-grade zones correspond to the area of native copper deposits …

Physics And Applications Of Exceptional Points, Qi Zhong

Dissertations, Master's Theses and Master's Reports

Exceptional points (EPs) are singularities that arise in non-Hermitian physics. Crossing EPs is believed to be related with phase transitions between parity-time-(PT-)symmetric phase and broken PT phase. Owing to their peculiar topology, EPs can remotely induce observable effects when encircled by closed trajectories in the parameter space. In this dissertation, first of all, we investigate the extreme dynamics of non-Hermitian systems near higher order EPs constructed using the bosonic algebra method. The strong power oscillations for certain initial conditions can occur as a result of the peculiar eigenspace geometry and its dimensionality collapse near these singularities. And in the PT …

Crack Pattern Simulation Of Pressurized Borosilicate Glass Tube Under Pellet Impact Using Ale Method, Omkar Bhumkar

Dissertations, Master's Theses and Master's Reports

Transformer bushings are a common target for sniper attacks to cause power failure in large areas. Given the size, internal pressure and brittle nature of transformer bushing, pellet impact causes damage to surrounding components due to broken bushing pieces. To mitigate this, a project was initiated by United States Burau of Reclaimation to develop a safety mechanism. Finite Element Analysis is proposed to optimize and reduce cost of the design.

A simplified Finite Element model is created which consists of 0.22 caliber lead pellet impacting Pyrex 7740 borosilicate glass tube. Previous studies on the effect of the mesh pattern, size …

Fortune And Failure - Gold And Silver Smelting In The Colorado Rockies 1861 To 1900, Andrew Mueller

Dissertations, Master's Theses and Master's Reports

This dissertation is a study of small-scale smelting in Colorado during the nineteenth century. Many small smelting enterprises were established throughout the mountains of the state from the mid-1860s to the mid-1880s. The smelters helped to revitalize a flagging mining industry by fostering its growth and, consequently, the development of the state before being outcompeted by larger smelting establishments developing in the growing cities on the Front Range. However, the life of these smelters was brief, and the majority failed within a few years. The role of these smelters in Colorado’s history has been largely overlooked but provide a rich …

Estimating The Spectrum In Computed Tomography Via Kullback–Leibler Divergence Constrained Optimization, Wooseok Ha, Emil Y. Sidky, Rina Foygel Barber, Taly Gilat Schmidt, Xiaochuan Pan

Biomedical Engineering Faculty Research and Publications

Purpose

We study the problem of spectrum estimation from transmission data of a known phantom. The goal is to reconstruct an x‐ray spectrum that can accurately model the x‐ray transmission curves and reflects a realistic shape of the typical energy spectra of the CT system.

Methods

Spectrum estimation is posed as an optimization problem with x‐ray spectrum as unknown variables, and a Kullback–Leibler (KL)‐divergence constraint is employed to incorporate prior knowledge of the spectrum and enhance numerical stability of the estimation process. The formulated constrained optimization problem is convex and can be solved efficiently by use of the exponentiated‐gradient (EG) …

Ct Automated Exposure Control Using A Generalized Detectability Index, P. Khobragade, Franco Rupcich, Jiahua Fan, Dominic J. Crotty, Naveen M. Kulkarni, Stacy D. O'Connor, W. Dennis Foley, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose

Identifying an appropriate tube current setting can be challenging when using iterative reconstruction due to the varying relationship between spatial resolution, contrast, noise, and dose across different algorithms. This study developed and investigated the application of a generalized detectability index (d'_gen) to determine the noise parameter to input to existing automated exposure control (AEC) systems to provide consistent image quality (IQ) across different reconstruction approaches.

Methods

This study proposes a task‐based automated exposure control (AEC) method using a generalized detectability index (d'_gen). The proposed method leverages existing AEC methods that are based on a prescribed …

Spatial And Temporal Influences On Discrimination Of Vibrotactile Stimuli On The Arm, Valay Shah, Maura Casadio, Robert A. Scheidt, Leigh A. Mrotek

Biomedical Engineering Faculty Research and Publications

Body–machine interfaces (BMIs) provide a non-invasive way to control devices. Vibrotactile stimulation has been used by BMIs to provide performance feedback to the user, thereby reducing visual demands. To advance the goal of developing a compact, multivariate vibrotactile display for BMIs, we performed two psychophysical experiments to determine the acuity of vibrotactile perception across the arm. The first experiment assessed vibration intensity discrimination of sequentially presented stimuli within four dermatomes of the arm (C5, C7, C8, and T1) and on the ulnar head. The second experiment compared vibration intensity discrimination when pairs of vibrotactile stimuli were presented simultaneously vs. sequentially …

Electro-Deposited Polyaniline On Tio2 As A Photoanode For Improved Photoelectrochemical Performance In Water Oxidation And Methylene Blue, Reeda Jamsri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Polyaniline (PANI) deposited on TiO2 as a photoanode has been synthesized by the electro-polymerization method. The electrodeposition was performed in aqueous solutions containing 0.5 M aniline and 1 M H2SO4 at a constant current density. The photoanode demonstrated its potential applications for photocatalytic degradation of methylene blue dye (MB) and photoelectrochemical (PEC) water splitting. A ~2.7 fold enhancement in the photodegradation activity at 0.9V vs. Ag/AgCl of a bias voltage and the high water oxidation photocurrent density of PANI/TiO2 on FTO photoanode achieves 1.3 mA cm-2 at 0.6V vs. Ag/AgCl under illumination which is higher than that pure TiO2 on …