Digital Commons Network^™

Measuring Influence Across Social Media Platforms: Empirical Analysis Using Symbolic Transfer Entropy, Abhishek Bhattacharjee

USF Tampa Graduate Theses and Dissertations

Social media platforms are interconnected environments that influence each other. Information from one social media platform spreads to another. This thesis proposes a platform-independent framework to analyze information transfer across social media platforms. This thesis uses Symbolic Transfer Entropy and Statistical Significance Test to measure influence and optimize the time window of influence between different platforms. To validate the framework, the thesis analyses the temporal activity dynamics and the information transfer across three different platforms, Reddit, Twitter and GitHub.

Two data driven studies are described in this thesis. The first study finds the optimum time windows of influence between the …

Cubesat Constellation Design For Intersatellite Linking, Michael T. White

USF Tampa Graduate Theses and Dissertations

This thesis investigates the concept of controlling a CubeSat constellation in low-Earth orbit. Low-Earth orbits are considered because the torque used for satellite control is supplied with magnetorquers, and the closer the satellite is to Earth’s magnetic field the more control gain can be supplied. Also, this is the expected orbit altitude of future CubeSat constellations to enable communications.

Controlling a CubeSat relies on attitude determination. This means being able to estimate its attitude relative to a given reference frame. To determine the attitude, we propose to use a star tracker and a Kalman filter. A star tracker scans the …

Prioritizing Rehabilitation Of Sanitary Sewers In Pinellas County, Fl, Jesse T. Hillman

USF Tampa Graduate Theses and Dissertations

Following large rain events, extraneous freshwater contributions known as inflow and infiltration (I/I) bypass the storm sewer and enter the sanitary sewer system. In areas with a high water table, like Pinellas County and the surrounding Tampa Bay area, a majority of the wastewater infrastructure is submerged year round exacerbating the rate of groundwater infiltration. This excess flow overloads the existing wastewater infrastructure leading to sanitary sewer overflows (SSOs). These SSOs result in serious problems for municipalities and utilities across the country.

This study was performed in order to assist Pinellas County Utilities in rehabilitating their southern sewer system. To …

Design And Testing Of Experimental Langmuir Turbulence Facilities, Zongze Li

USF Tampa Graduate Theses and Dissertations

Langmuir Circulation is a common phenomenon driven by wind in oceans and lakes and was first studied by Langmuir in 1927. According to various ocean observations, this kind of phenomenon plays an important role in many phenomena such as the aggregation of bubbles, the distribution of plankton as well as the mixing of spilled oil and sediment in the ocean. To study this, an experimental facility has been developed in the lab which creates a small scale version of Langmuir Circulation.

This thesis is about the design and testing of this tank and surrounding aluminum frame, as well as the …

Statistical Anomaly Detection And Mitigation Of Cyber Attacks For Intelligent Transportation Systems, Ammar Haydari

USF Tampa Graduate Theses and Dissertations

Secure vehicular communication is a critical factor for secure traffic management. Perfect security in intelligent transportation systems (ITS) has solid and efficient intrusion detection systems (IDS). In this paper, we consider false data injection attacks and distributed denial-ofservice attacks (DDoS), especially the stealth low-rate DDoS attacks, targeting the integrity and availability, respectively, in vehicular ad-hoc networks (VANET). Novel statistical intrusion detection and mitigation techniques are proposed for the considered attacks. The performance of the proposed methods are evaluated using a traffic simulator and a real traffic dataset. Comparisons with the state-of-the-art solutions clearly demonstrate the superior performance of the proposed …

Autonomous Monocular Obstacle Detection For Avoidance In Quadrotor Uavs, Panos Valavanis

USF Tampa Graduate Theses and Dissertations

Unmanned Aircraft Systems (UAS) research and development and applications have witnessed unprecedented levels of growth in the past two decades. Although military applications have dominated the market, it is anticipated and expected that civilian and public domain applications will be dominant in the future. Consequently, gradual and timely integration of unmanned aviation into the National Airspace System (NAS) is a real challenge, and roadmaps towards achieving full integration are already in place in the US, Canada, Australia, South Africa and European Union (EU). However, before com- plete integration of manned-unmanned aviation, additional challenging problems need to be addressed and solved, …

Density-Mediated Interactions Are Stronger But More Variable Than Trait-Mediated Interactions In Predator–Prey Systems, Travis M. Flock

USF Tampa Graduate Theses and Dissertations

Theoretical and empirical considerations of predator-prey dynamics have sought to determine the dominant of two effects exerted by predators onto prey: consumptive effects of predators and non-consumptive, or trait-mediated, effects. Many studies have identified trait-mediated interactions (TMIs) in diverse taxa, and meta-analyses of these studies found that prey population dynamics are as strongly – if not more strongly – affected by TMIs as density-mediated interactions (DMIs). Since then, there is now an expanded primary literature, and given this potential for new insight on the direct and indirect effect of predators on prey, the cost of traits involved in TMIs relative …

Authentication And Sql-Injection Prevention Techniques In Web Applications, Cagri Cetin

USF Tampa Graduate Theses and Dissertations

This dissertation addresses the top two “most critical web-application security risks” by combining two high-level contributions.

The first high-level contribution introduces and evaluates collaborative authentication, or coauthentication, a single-factor technique in which multiple registered devices work together to authenticate a user. Coauthentication provides security benefits similar to those of multi-factor techniques, such as mitigating theft of any one authentication secret, without some of the inconveniences of multi-factor techniques, such as having to enter passwords or biometrics. Coauthentication provides additional security benefits, including: preventing phishing, replay, and man-in-the-middle attacks; basing authentications on high-entropy secrets that can be generated and updated automatically; …

Steady State Hydroplaning Risk Analysis And Evaluation Of Unsteady State Effects, Menna Yassin

USF Tampa Graduate Theses and Dissertations

Hydroplaning is a major concern on high speed roadways during heavy rainfall events. Hydroplaning tools are widely used by designers to reduce their roadway’s hydroplaning potential, therefore reducing the possibilities of severe crashes. This dissertation presents two methodologies for improving the prediction of hydroplaning potential.

The first phase focused on improving an existing widely used software called PAVDRN. Using multiple datasets from the Florida Department of Transportation, the author filtered the data using specific criteria to leave only truly dynamic hydroplaning crashes. The author then evaluated PAVDRN’s prediction capabilities and assessed its reliability in predicting a hydroplaning crash. Using past …

Weaved Journeys: Life Writings Of Leading And Engagement In Science Education, Tara M. Nkrumah

USF Tampa Graduate Theses and Dissertations

This study’s purpose was to explore science engagement and in/equity through science educators’ narratives of servant leadership at both the K-12 and higher education levels in the United States. The research question was: How have participants become and led others to become engaged in science? I took an arts-based approach using drawings and autobiographical data to initiate and create metissages focused on becoming engaged in science education. The findings were that: (1) Participants helped marginalized students understand the culture of science through pedagogical strategies that connected self and science; (2) Participants recognized and countered systemic forms of oppression for students …

Generalized Derivations Of Ternary Lie Algebras And N-Bihom-Lie Algebras, Amine Ben Abdeljelil

USF Tampa Graduate Theses and Dissertations

We generalize the results of Leger and Luks and other researchers about generalized derivations to the cases of ternary Lie algebras and n-BiHom Lie algebras. We investigate the derivations algebras of ternary Lie algebras induced from Lie algebras, we explore the subalgebra of quasi-derivations and give their properties. Moreover, we give a classification of the derivations algebras for low dimensional ternary Lie algebras.

For the class of n-BiHom Lie algebras, we study the algebras of generalized derivations and prove that the algebra of quasi-derivations can be embedded in the derivation algebra of a larger n-BiHom Lie algebra.

Malicious Manipulation In Service-Oriented Network, Software, And Mobile Systems: Threats And Defenses, Dakun Shen

USF Tampa Graduate Theses and Dissertations

This dissertation includes three approaches we have been designed to tackle threats and challenges in network, software, and mobile security. The first approach demonstrates a new class of content masking attacks against the Adobe PDF standard, causing documents to appear to humans dissimilar to the underlying content extracted by information-based services. The second work protects sensitive data in binaries from being corrupted by cyber attackers. The last work proposes a mechanism which utilizes the unique walking patterns inherent to humans and differentiate our work from other walking behavior studies by using it as first-order authentication and developing matching methods fast …

Functional Porous Materials: Applications For Environmental Sustainability, Briana Amaris Aguila

USF Tampa Graduate Theses and Dissertations

Resource depletion, clean water shortages, and global climate change have led to environmental sustainability being of primary concern for both governmental and industrial practices. Current methods to address these challenges typically come as a double-edged sword, fixing one problem while contributing to another. As introduced in chapter one of this dissertation, adsorbent materials are seen as a promising alternative remediation system due to their low energy consumption and minimal chemical waste production. However, many traditional adsorbents, such as activated carbon, metal oxides, and resins, are hindered in practice. This is because they lack the structural tunability to have long-term effectiveness …

Probabilistic And Statistical Prediction Models For Alzheimer’S Disease And Statistical Analysis Of Global Warming, Maryam Ibrahim Habadi

USF Tampa Graduate Theses and Dissertations

The importance and applicability of data-driven statistical models have increased significantly. This current study, we have utilized statistical techniques in interdisciplinary research, including environmental and health.

Environmentally, global warming is considered one of the critical issues facing our planet. It is the increase in average global temperatures caused mostly by increases in Carbon Dioxide CO₂. The excessive rise of carbon dioxide from the average level as the side effect of the industrial revolution has a significant impact on blocking the heat and increase the temperature within the Earth’s atmosphere. Based on the record of total CO₂ emissions …

Cross Layer-Based Intrusion Detection System Using Machine Learning For Manets, Amar Amouri

USF Tampa Graduate Theses and Dissertations

Intrusion Detection systems plays a crucial role in detecting malicious activities that deteriorate the performance of the network. Mobile AdHoc Networks (MANETs) and Wireless Sensor Networks (WSNs) are a type of wireless networks that can deliver data without any need of infrastructure for their operation. The distributed nature of these networks and the limited resources available, pose a huge challenge for the security of a network. The need for an IDS that can adapt with such challenges is of utmost importance.

Two IDS schemes are presented in this dissertation; the first scheme is based on utilizing the promiscuous mode based …

Illuminating Changes In Preservice Teachers’ Perceptions About Teaching Elementary Mathematicsin An Introductory Methods Course, Elaine Cerrato

USF Tampa Graduate Theses and Dissertations

Producing highly skilled elementary mathematics teachers capable of facilitating mathematics learning in ways aligned with The Principles and Standards for School Mathematics (NCTM, 2000) and the Common Core State Standards for Mathematics (CCSSM), is a common objective of teacher preparation programs (National Governors Association & Chief Council of State School Officers, 2010). After decades of effort, Brown (2003) argues, teachers continue to teach in the way they were taught; thus, they disregard mathematics standards. As Abell, Appleton, and Hanuscin (2010) note, students’ preexisting ideas relevant to the nature of learning and teaching stem from experiences in their schooling, life, and …

Palatable Shades Of Gender: Status Processes At The Intersections Of Race, Gender, And Team Formation, Jasmón L. Bailey

USF Tampa Graduate Theses and Dissertations

This dissertation addresses the importance of studying how race and gender influence partner selection processes of team formation. Stratified social systems influence the choice and decision-making behaviors that shape group and team formation (Hechter 1978). By testing Skvoretz’s and Bailey’s (2016) formal theory of team formation choice processes derived from expectation states theory, the dissertation aims to understand how race and gender influence a person’s choice and decision-making with respect to forming a group of problem-solving teammates. Through a quasi-experimental research design, subjects participate in simulated interactive environments in which they can select and personalize self-represented avatars and then choose …

Phase Evolution And Dynamic Behavior In Materials With Noncollinear Spin Textures, Eleanor M. Clements

USF Tampa Graduate Theses and Dissertations

Noncentrosymmetric magnetic materials have gained special attention due to their ability to stabilize topologically nontrivial magnetic states via the competition between symmetric exchange and the antisymmetric Dzyaloshinskii-Moriya (DM) interaction. The spin struc- tures in these materials have become a center of interest for spintronics applications due to their stable, particle-like properties, and high degree of tunability via control of external parameters, such as magnetic and/or electric field and temperature. Understanding how these robust magnetic structures stabilize, evolve, dynamically respond, and adhere to existing models, all in the presence of external stimuli, are topics of fundamental interest. In this dissertation, the …

Water And Salt At The Lipid-Solvent Interface, James M. Kruczek

USF Tampa Graduate Theses and Dissertations

Lipid bilayers are important biological structures. The changes in bilayer properties are induced by the composition of the bilayer as well as the solvent. In this work, we study the effects of different molecular makeups of lipids and ionic solvents with molecular dynamics simulations to determine their effect on the bilayer interface. In particular, we look at how different carbon chain bindings affect water viscosity at the interface and allow for a less permeable bilayer. Additionally, we examine the changes to the bilayer due to the presence of the most biologically relevant salt ions. Lastly, we show how the pharmacological …

The Potential Of Marine Microbes, Flora And Fauna In Drug Discovery, Santana Alexa Lavonia Thomas

USF Tampa Graduate Theses and Dissertations

Natural products are chemical compounds synthesized by a living organism. These compounds have been utilized by humans from ancient times to the present for their pharmacological and biological activities. Terrestrial organisms are considered a lucrative source of bioactive compounds and chemical diversity. Within the past 60 years, the marine environment has presented its potential as a validated source for structural diversity and biologically active compounds. Technology has given access from shallow waters down to the abyssal plane for exploration and investigation of the inhabitants. Marine organisms have displayed their benefits in the pharmaceutical industry with the approval of several marine-derived …

Cooperation In Community Colleges, Frederic S. Gore

USF Tampa Graduate Theses and Dissertations

With the mounting pressures on institutions of higher education to do more with limited resources, the opportunity to collaborate with other colleges has emerged as a viable tool to create efficiencies and obtain valuable knowledge otherwise unattainable by an institution, even if that collaboration takes place with a competing institution. Enterprise resource planning (ERP) systems are critical to managing student information and college operations, but can be challenging for colleges to implement. Consortia present a unique solution to colleges to address gaps in their expertise and skills needed to achieve a successful ERP implementation. This study explores the factors that …

Development And Validation Of Advanced Techniques For Treatment Planning And Verification In Megavoltage Radiotherapy, Saeed Ahmed

USF Tampa Graduate Theses and Dissertations

The aim of this work is primarily to validate the advanced techniques for treatment planning and dosimetric verification for modern megavoltage x-ray radiotherapy. With the advent of modern radiotherapy techniques, there is a great need for assuring quality of the radiation dose distributions generated by the advanced intensity modulated treatments (IMRT/VMAT). This is typically accomplished by the assessment of the treatment plan quality at the planning stage and then verification of the dose distributions through measurements on the phantoms or independent dose calculations prior to the actual delivery of these plans to patients. The major focus of this work is …

Documenting Evolution: Comparing And Contrasting Late Mesozoic And Late Cenozoic Molluscan Patterns, Joshua Slattery

USF Tampa Graduate Theses and Dissertations

Despite major advances, evolutionary theory still has numerous shortcomings in terms of fully understanding the controls on speciation and diversification. A major factor limiting our knowledge is how biology and paleobiology view speciation from separate micro- and macro-evolutionary perspectives, respectively. Biologists typically examine microevolutionary changes within species from various biogeographic, behavioral, morphological, and genetic perspectives, which contrasts to the macroevolutionary approach of most paleobiologists, who have examined the same phenomena at larger scales but with the standpoint of time, have also concentrated on aspects of global or regional diversification (e.g., richness, origination rates, and extinction rates) over the long-term. Noticeably …

Essays On Time Series And Machine Learning Techniques For Risk Management, Michael Kotarinos

USF Tampa Graduate Theses and Dissertations

The Capital Asset Pricing Model combined with the Sharpe ratio is a standard method for choosing assets for selection in a portfolio. However, this method has many structural issues and was designed for a time when high dimensional computing was in its infancy. An alternative to these methods using a mix of Multi-Level Time Series Clustering, the MACBETH algorithm and traditional time series techniques was constructed that minimized data loss and allow for customized portfolio construction for investors with different risk profiles and specialized investment needs. It was shown that these methods are adaptable to cloud computing environments and allow …

Studies Of The Long-Term Change Of Global Mean And Regional Sea Surface Height, Yingli Zhu

USF Tampa Graduate Theses and Dissertations

Sea level change could have profound impacts on our society. We report here on three related sea level change problems. First, a variety of regression models have predicted different rates for global mean sea level rise over the past century. Some of these models are accelerating and others are not. We ask whether we can distinguish between these using a new nonparametric noise model that we have developed. Simulations show that we can, and further imply that GMSL is rising at an accelerating rate. Second, historical global mean sea level is reconstructed from tide gauges that are located along coastlines …

The Textbook Decision: Purchasing Options Affecting Students In The Classroom, Josef Rill

USF Tampa Graduate Theses and Dissertations

This dissertation examined the relationship of student textbook purchasing practices to student success and satisfaction in selected general education undergraduate courses at a Florida public community college. The study utilized secondary data sources, specifically bookstore purchasing data, student records, and student satisfaction survey results. Descriptive statistics and ANOVA were used to determine relationships. Seven specific research questions were answered, and statistically significant results were identified as a result of the data analysis.

The results indicated that there was a relationship between the type of textbook/course material purchased or rented and a student’s final grade in a course. There was also …

Volcanic Electrification: A Multiparametric Case Study Of Sakurajima Volcano, Japan, Cassandra M. Smith

USF Tampa Graduate Theses and Dissertations

Electrical activity at volcanoes has been recently recognized as a potential new remote sensing technique for plume-forming eruptions. Volcanic electrical activity takes place in the conduit and plume and therefore has the benefit of being a direct indicator of surface activity. This is unlike seismic signals, which indicate magma/gas movement underground, and infrasound signals, which indicate a surface explosion but not necessarily the formation of an ash plume. There are two distinct types of volcanic electrical discharges: volcanic lightning and continual radio frequency (CRF) impulses. This dissertation explores the relationships between these two electrical signals and other commonly monitored volcanic …

Dynamic Pricing Of Electricity And Demand Response In Smart Communities, Vignesh Subramanian

USF Tampa Graduate Theses and Dissertations

Grid modernization using advanced metering infrastructure (AMI) will continue to enhance timely communication among the system operator (SO), producers, and consumers. This will further empower the vision of dynamic pricing and demand side management (DSM). The phrase dynamic pricing in this dissertation refers to the practice of disclosing binding prices of electricity just ahead of consumption. As regards DSM, the focus is on collective demand response (DR) by aggregators managing consumers’ loads in smart and connected communities (households, businesses, industries and aggregation of electric vehicle batteries). However, practitioners and researchers alike have expressed the fear that dynamic pricing may cause …

Piezoelectric Zno Nanowires As A Tunable Interface Material For Opto-Electronic Applications, Anand Kumar Santhanakrishna

USF Tampa Graduate Theses and Dissertations

Organic electronic devices are sustainable alternatives to the conventional electronics, due to their advantages of low cost, mechanical flexibility and wide range of applications. With the myriad list of organic materials available today, the opportunities to imagine new innovative devices are immense. Organic electronic devices such as OLEDs (organic light emitting diode), OPVs (Organic photovoltaics) and OFETs (organic field effect transistors) are among the leading device categories. Although OLED’s have been a huge commercial success, other categories are not lagging.

Radical thinking is necessary to improve on the current performances of these devices. One such thinking is to combine the …

Past Hydroclimate And Vegetation Variation In Romania Inferred From Isotopic Geochemistry And Pollen Of Cave Bat Guano, Daniel Martin Cleary

USF Tampa Graduate Theses and Dissertations

While an abundance of paleo-records related to hydroclimate and vegetation exist in East-Central Europe, currently there is a scarcity of reconstructions that have the resolution to effectively capture the past 2000 years. A more complete understanding of this interval is important as it includes significant climatic events such as the Medieval Warm Period, Little Ice Age, and the post-industrial revolution human induced climate change. A solution to increasing our understanding of these events is the use of cave bat guano, a relatively underutilized source of climatic information.

Cave bat guano piles commonly have near annual deposition and in Europe can …