Digital Commons Network^™

Shortcut Nitrogen Removal In Photo-Sequencing Batch Reactor, Experiments, Dynamic Model And Full-Scale Design, Sahand Iman Shayan

USF Tampa Graduate Theses and Dissertations

Nitrogen is one of the essential elements for life; however, inefficient use of nitrogen creates major environmental problems. Nitrogen-rich streams from urban areas, farms, and wastewater treatment plants (WWTPs) lead to surface and groundwater contamination, resulting in eutrophication, hypoxia, and notable environmental, public health and economic damage. Ammonia is a form of nitrogen that can be created during industrial or biological nitrogen fixation or decomposition of biomass. Anaerobic digesters (ADs) in WWTP generate biogas from collected sludge from primary and secondary clarifiers to achieve energy recovery in the plant. However, sidestream effluent from dewatering AD sludge contains high concentrations of …

Low-Cost Device For Laser Phacoemulsification: A Preliminary Study, Mitchell Harrah

USF Tampa Graduate Theses and Dissertations

The current gold standard of cataract removal surgery is phacoemulsification systems. These are divided based on the type of devices used; both are considered equal but with different delivery modes. These delivery methods are either acoustic or light-based. However, these devices pose two hurdles for impoverished areas: high costs and heavy resource usage. This thesis proposes a novel phacoemulsification system is based on the low-cost, off-shelf laser diodes that implement light-based phacoemulsification of cataracts. The system is tested for viability over two methods: finite element analysis and experimentation on various phantoms. Simulations on the device have occurred on the COMSOL …

Evaluation Of Structural Equation Modeling (Sem) Fit Indices In Distinguishing Between Circumplex And Other Factor Models, Andrew J. Thurston

USF Tampa Graduate Theses and Dissertations

The circumplex offers a useful paradigm for simultaneously modeling relationships between latent variables and visually representing an individual’s profile. Previous research has demonstrated the Circular Stochastic Process Model (CSPM) can establish the presence of the circumplex in sample data using Confirmatory Factor Analysis (CFA), allowing researchers to test the circumplex with familiar global fit indices such as the Confirmatory Fit Index (CFI), Tucker-Lewis Index (TLI), Root Mean Squared Error of Approximation (RMSEA), and Unbiased Standardized Root Mean Squared Residual (SRMRu). However, it is not yet clear if these fit indices are sensitive to detect circumplexes under a variety of conditions. …

Statistical Models To Test Measurement Invariance With Paired And Partially Nested Data: A Monte Carlo Study, Diep Thi Nguyen

USF Tampa Graduate Theses and Dissertations

While assessing emotions, behaviors or performance of preschoolers and young children, scores from adults such as parent psychiatrist and teacher ratings are used rather scores from children themselves. Data from parent ratings or from parents and teachers are often nested such as students are within teachers and a child is within their parents. This popular nested feature of data in educational, social and behavioral sciences makes measurement invariance (MI) testing across informants of children methodologically challenging. There was lack of studies that take into account the nested structure of data in MI testing for multiple adult informants, especially no simulation …

Measuring Flowering Phenology And Its Consequences: A Systematic Review, Samantha M. Mangum

USF Tampa Graduate Theses and Dissertations

Despite growing interest in flowering phenology among ecologists, as reflected by an increase in the number of papers, there is little information on how studies typically measure and describe a plant’s flowering phenology. The focus of this study was the literature on flowering phenology and the approaches researchers have taken to quantify flowering phenology. Initially, a comprehensive description of the breath of literature on flowering phenology was produced. From there, I described the current research on flowering phenology: the year that the studies were published, the locations of the studies, and the particular biomes where the studies were performed. The …

Testing And Packaging For Mems Acoustic Emission Sensors, Ting-Hung Liu

USF Tampa Graduate Theses and Dissertations

The goal of this research is to improve the structure and dimension of the MEMS acoustic emission sensor. Acoustic emission sensor (AE sensor) based on the piezoelectric transducer is a well-developed technology in non-destructive testing that is widely used to determine permanent damage such as cracks and corrosions in buildings and structures. The AE sensor can be used to monitor cracks in structures and to check leakage in pressurized systems. The location of cracks in a structure or system leakage causes a high-frequency surface vibration while releasing ultrasonic energy. The frequency of this energy is typically between 30 kHz to …

Conformational Fluctuations Of Biomolecules Studied Using Molecular Dynamics And Enhanced Sampling, Geoffrey M. Gray

USF Tampa Graduate Theses and Dissertations

Biomolecule structural fluctuations determine function, regulating numerous biological processes My research has shed light on several interesting cases in which structural fluctuations have been identified to assess functional differences. Chapter 2 discusses the effects of structural rearrangement of the β2-β3 loop on the DNA binding affinity of the type 6 human papillomavirus E2 protein. Chapter 3 investigates the effects of phosphorylation on the C-terminal domain of Cdc37, a protein important in the Hsp90 chaperone cycle. Chapter 4 studies the effects on cyclycization on the conformational fluctuations of a γ-AApeptide used for high-throughput libraries. Chapter 5 is a structural study on …

Development Mems Acoustic Emission Sensors, Adrian Enrique Avila Gomez

USF Tampa Graduate Theses and Dissertations

The purpose of this research is to develop MEMS based acoustic emission sensors for structural health monitoring. Acoustic emission (AE) is a well-established nondestructive testing technique that is typically used to monitor for fatigue cracks in structures, leaks in pressurized systems, damages in composite materials or impacts. This technology can offer a precise evaluation of structural conditions and allow identification of imminent failures or minor failures that can be addressed by planned maintenances routines. AE causes a burst of ultrasonic energy that is measured as high frequency surface vibrations (30 kHz to 1 MHz) generated by transient elastic waves that …

Multi-Step Tokenization Of Automated Clearing House Payment Transactions, Privin Alexander

USF Tampa Graduate Theses and Dissertations

Since its beginnings in 1974, the Automated Clearing House (ACH) network has grown into one of the largest, safest, and most efficient payment systems in the world. An ACH transaction is an electronic funds transfer between bank accounts using a batch processing system.

Currently, the ACH Network moves almost $43 trillion and 25 billion electronic financial transactions each year. With the increasing movement toward an electronic, interconnected and mobile infrastructure, it is critical that electronic payments work safely and efficiently for all users. ACH transactions carry sensitive data, such as a consumer's name, account number, tax identification number, account holder …

Voltage Droop Analysis And Mitigation In Sttram-Based Last Level Cache, Radha Krishna Aluru

USF Tampa Graduate Theses and Dissertations

Preferred especially for a Last Level Cache (LLC) due to its high retention and tolerance capabilities, Spin-Transfer Torque Random Access Memory (STTRAM) is an emerging and a promising Non-Volatile Memory (NVM) technology. To switch the magnetization of a Magnetic Tunnel Junction (MTJ), the amount of current needed is very high (~100μA per bit). For a full cache line (512-bit) write, this extremely high current results in a voltage droop in the conventional cache architecture. Due to this droop, the write operation fails especially when the farthest bank of the cache is accessed. In this thesis, we perform an analysis of …

The Development Of A Prosthetic Training Software For Upper Limb Amputees, Tyler Kayne Sullins

USF Tampa Graduate Theses and Dissertations

The purpose of this study was to develop an intuitive software that aids in the field of prosthetic training and rehabilitation by creating an individualized visualization of joint angles. This software is titled “the prosthetic training software (PTS) for individualized joint angle representation”, and it enables the individualized portrayal of predicted or pre-recorded joint angles. The PTS is an intuitive program for clinicians and prosthesis users that produces an animation of a virtual avatar reflecting the user’s segment lengths and amputation for rehabilitation and training purposes.

The PTS consists of a graphical user interface (GUI) and a 3D visualization of …

Enhancement Of Supercapacitor Energy Storage By Leakage Reduction And Electrode Modification, Tete Tevi

USF Tampa Graduate Theses and Dissertations

Supercapacitors have emerged in recent years as a promising energy storage technology. The main mechanism of energy storage is based on electrostatic separation of charges in a region at the electrode-electrolyte interface called double layer. Various electrode materials including carbon and conducting polymers have been used in supercapacitors. Also, supercapacitors offer high life cycle and high power density among electrochemical energy storage devices. Despite their interesting features, supercapacitors present some disadvantages that limit their competitivity with other storage devices in some applications. One of those drawbacks is high self-discharge or leakage. The leakage occurs when electrons cross the double layer …

Active Tile Self-Assembly And Simulations Of Computational Systems, Daria Karpenko

USF Tampa Graduate Theses and Dissertations

Algorithmic self-assembly has been an active area of research at the intersection of computer science, chemistry, and mathematics for almost two decades now, motivated by the natural self-assembly mechanism found in DNA and driven by the desire for precise control of nanoscale material manufacture and for the development of nanocomputing and nanorobotics. At the theoretical core of this research is the Abstract Tile Assembly Model (aTAM), the original abstract model of DNA tile self-assembly. Recent advancements in DNA nanotechnology have been made in developing strand displacement mechanisms that could allow DNA tiles to modify themselves during the assembly process by …

A Comparative Evaluation Of The Learner Centered Grading Debriefing Method In Nursing Education, Marisa J. Belote

USF Tampa Graduate Theses and Dissertations

The nursing discipline lacks a consensus on a best practice method for debriefing students following simulation-based training. A recognized, standardized method does not exist and various methods are utilized within the domain. The similarities between aviation and healthcare are well documented. Training members of both disciplines require standardization and methods of best practice. The aviation industry through the Federal Aviation Administration has found Learner Centered Grading (LCG) to be a successful educational format. The utilization of the LCG Debriefing method in simulation-based training is the standardized debriefing format for a technologically dynamic industry.

The aim of this research was to …

High Dimensional Non-Linear Optimization Of Molecular Models, Joseph C. Fogarty

USF Tampa Graduate Theses and Dissertations

Molecular models allow computer simulations to predict the microscopic properties of macroscopic systems. Molecular modeling can also provide a fully understood test system for the application of theoretical methods. The power of a model lies in the accuracy of the parameter values which govern its mathematical behavior. In this work, a new software, called ParOpt, for general high dimensional non-linear optimization will be presented. The software provides a very general framework for the optimization of a wide variety of parameter sets. The software is especially powerful when applied to the difficult task of molecular model parameter optimization. Three applications of …

Photonic Crystal-Based Flow Cytometry, Justin William Stewart

USF Tampa Graduate Theses and Dissertations

Photonic crystals serve as powerful building blocks for the development of lab-on-chip devices. Currently they are used for a wide range of miniaturized optical components such as extremely compact waveguides to refractive-index based optical sensors. Here we propose a new technique for analyzing and characterizing cells through the design of a micro-flow cytometer using photonic crystals. While lab scale flow cytometers have been critical to many developments in cellular biology they are not portable, difficult to use and relatively expensive. By making a miniature sensor capable of replicating the same functionality as the large scale units with photonic crystals, we …

The Performance Of The Linear Logistic Test Model When The Q-Matrix Is Misspecified: A Simulation Study, George T. Macdonald

USF Tampa Graduate Theses and Dissertations

A simulation study was conducted to explore the performance of the linear logistic test model (LLTM) when the relationships between items and cognitive components were misspecified. Factors manipulated included percent of misspecification (0%, 1%, 5%, 10%, and 15%), form of misspecification (under-specification, balanced misspecification, and over-specification), sample size (20, 40, 80, 160, 320, 640, and 1280), Q-matrix density (60% and 46%), number of items (20, 40, and 60 items), and skewness of person ability distribution (-0.5, 0, and 0.5). Statistical bias, root mean squared error, confidence interval coverage, confidence interval width, and pairwise cognitive components correlations were computed. The impact …

Packet Coalescing And Server Substitution For Energy-Proportional Operation Of Network Links And Data Servers, Mehrgan Mostowfi

USF Tampa Graduate Theses and Dissertations

Electricity generation for Information and Communications Technology (ICT) contributes over 2% of the human-generated CO2 to the atmosphere. Energy costs are rapidly becoming the major operational expense for ICT and may soon dwarf capital expenses as software and hardware continue to drop in price. In this dissertation, three new approaches to achieving energy-proportional operation of network links and data servers are explored.

Ethernet is the dominant wireline communications technology for Internet connectivity. IEEE 802.3az Energy Efficient Ethernet (EEE) describes a Low Power Idle (LPI) mechanism for allowing Ethernet links to sleep. A method of coalescing packets to consolidate link idle …

Applications Of Agent Based Approaches In Business: A Three Essay Dissertation, Shankar Prawesh

USF Tampa Graduate Theses and Dissertations

The goal of this dissertation is to investigate the enabling role that agent based simulation plays in business and policy. The aforementioned issue has been addressed in this dissertation through three distinct, but related essays. The first essay is a literature review of different research applications of agent based simulation in various business disciplines, such as finance, economics, information systems, management, marketing and accounting. Various agent based simulation tools to develop computational models are discussed. The second essay uses an agent-based simulation approach to study important properties of the widely used most popular news recommender systems (NRS). This essay highlights …

A Methodology For Scheduling Operating Rooms Under Uncertainty, Marbelly Paola Davila

USF Tampa Graduate Theses and Dissertations

An operating room (OR) is considered to be one of the most costly functional areas within hospitals as well as its major profit center. It is known that managing an OR department is a challenging task, which requires the integration of many actors (e.g., patients, surgeons, nurses, technicians) who may have conflicting interests and priorities.

Considering these aspects, this dissertation focuses on developing a simulation based methodology for scheduling operating rooms under uncertainty, which reflects the complexity, uncertainty and variability associated with surgery.

We split the process of scheduling ORs under uncertainty into two main components. First, we designed a …

A Study On Lane-Change Recognition Using Support Vector Machine, Weiping Deng

USF Tampa Graduate Theses and Dissertations

This research focuses primary on recognition of lane-change behaviors using support vector machines (SVMs). Previous research and statistical results show that the vast majority of motor vehicle accidents are caused by driver behavior and errors. Therefore, the interpretation and evaluation of driver behavior is important for road safety analysis and improvement. The main limit to understanding driver behavior is the data availability. In particular, a full-scale lane-change data set is difficult to collect in a real traffic environment because of the safety and cost issues. Considering the data demands of the recognition model development and the obstacles of field data …

Analyses Of Variable Refrigerant Flow And Exergy In Air Conditioning Systems, Rashid Ali Alshatti

USF Tampa Graduate Theses and Dissertations

This thesis consists of two research problems in the air conditioning (A/C) area. For the first problem, the aim is to model and simulate a variable refrigerant flow (VRF) air conditioning system. The coefficient of performance (COP) for refrigeration or heat pump system is one of the critical parameters for designing an air conditioning system. The modeling of the system components for a VRF cycle under different cooling conditions using R-134a and R-22 as refrigerants was carried out. Calculations were performed by varying different parameters such as condenser and evaporator temperatures, and refrigerant type. The R-134a refrigerant shows a better …

Operational Performance Evaluation Of Four Types Of Exit Ramps On Florida's Freeways, Linjun Lu

USF Tampa Graduate Theses and Dissertations

This research focuses primarily on the analysis of exit ramp performance related to safety and operations. The safety analysis focuses on the impacts of different exit ramp types for freeway diverge areas and different factors contributing to the crashes that occur on the exit ramp sections. The operational analysis is based mainly on simulations by TSIS-CORSIM. Different ramp effects and guidance for selecting optimal exit ramp type are concluded. Issues related to ramp sections and crossroad sections are also demonstrated. Minimum ramp length and minimum distance between ramp terminal and downstream or upstream intersections are calculated. The operational analysis was …

Meta-Analysis Of Single-Case Data: A Monte Carlo Investigation Of A Three Level Model, Corina M. Owens

USF Tampa Graduate Theses and Dissertations

Numerous ways to meta-analyze single-case data have been proposed in the literature, however, consensus on the most appropriate method has not been reached. One method that has been proposed involves multilevel modeling. This study used Monte Carlo methods to examine the appropriateness of Van den Noortgate and Onghena's (2008) raw data multilevel modeling approach to the meta-analysis of single-case data. Specifically, the study examined the fixed effects (i.e., the overall average baseline level and the overall average treatment effect) and the variance components (e.g., the between person within study variance in the average baseline level, the between study variance in …

Asymmetric Passive Dynamic Walker Used To Examine Gait Rehabilitation Methods, John Sushko

USF Tampa Graduate Theses and Dissertations

Testing gait rehabilitation devices on humans can be a difficult task, due to the effects of the neurological controls of the human body. This thesis advances the use of a passive dynamic walker (PDW) tuned to have asymmetric gait patterns similar to those with physical impairments to test rehabilitation devices. A passive dynamic walker is a multipendulum system that has a stable gait pattern when walking down a slope without any energy inputs except the forces due to gravity. A PDW model is better suited for testing rehabilitation devices because it has been shown to resemble human gait and separates …

Modeling And Analysis Of Cooperative Search Systems, Carlos A. Portilla

USF Tampa Graduate Theses and Dissertations

The analysis of performance gains arising from cueing in cooperative search

systems with autonomous vehicles has been studied using Continuous Time Markov

Chains; where the search time distributions are assumed to follow the exponential

distributions. This work proposes the use of Petri Nets to model and analyze these

systems. The Petri Net model considers two types of autonomous vehicles: a search-only

vehicle and n search-engage vehicles. Specific performance metrics are defined to

measure system’s performance. Through simulation, it is shown that the search time with

stationary targets and cues that provide exact target location follows a triangular

distribution. A methodology …

Improving The Energy Efficiency Of Ieee 802.3az Eee And Periodically Paused Switched Ethernet, Mehrgan Mostowfi

USF Tampa Graduate Theses and Dissertations

It is estimated that networked devices consumed about 150 TWh of electricity in 2006 in the

U.S. which has cost around $15 billion and contributed about 225 billion lbs of CO

2

to

greenhouse gas emissions. About 13.5% of this energy is consumed by network equipment such

as switches and routers.

This thesis addresses the energy consumption of Ethernet, and designs and evaluates

improvements on existing methods to reduce the energy consumption of Ethernet links and

switches.

Energy Efficient Ethernet (EEE) is an emerging IEEE 802.3 standard which allows Ethernet

links to sleep when idle. In this thesis, a performance …

Improving Ad-Hoc Team Performance Using Video Games, Jeff David Craighead

USF Tampa Graduate Theses and Dissertations

This dissertation examined the effects of distributed, multiplayer training video games on the performance of distributed teams of robot operators. Two hypotheses were tested, the first hypothesis stated that online, game-based team training will improve the performance of an ad-hoc team versus an ad-hoc team formed of individually trained teammates. The second hypothesis stated that the fractal dimension of a robot's path can be used as an indicator of its operator's skill. Forty-one volunteers participated in an experiment in which they played a distributed, online training game which showed them the basics of operating an Inuktun Extreme VGTV for a …

2-D Finite Element Modeling For Nanoindentation And Fracture Stress Analysis, Chi Chen

USF Tampa Graduate Theses and Dissertations

In Chapter 1, a brief introduction of nanoindentation and finite element method is presented. General procedures have been developed based on FEM modeling of nanoindentation data to obtain the mechanical properties of thin films. Selected FEM models are illustrated in detail.

In Chapter 2, nanoindentation test is simulated using finite element method based on contact mechanics approach. The relationship between load and indentation depth is obtained. The numerical results show good agreement with experimental data. It is shown that FEM is an effective tool for simulation of nanoindentation tests of metallic films. However, limitations caused by simplification of models and …

Predicting The Medical Management Requirements Of Large Scale Mass Casualty Events Using Computer Simulation, Scott A. Zuerlein

USF Tampa Graduate Theses and Dissertations

Recent events throughout the world and in the US lend support to the belief that another terrorist attack on the US is likely, perhaps probable. Given the potential for large numbers of casualties to be produced by a blast using conventional explosives, it is imperative that health systems across the nation consider the risks in their jurisdictions and take steps to better prepare for the possibility of an attack. Computer modeling and simulation offers a viable and useful methodology to better prepare an organization or system to respond to a large scale event. The real question, given the shortage, and …