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USF Tampa Graduate Theses and Dissertations

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Full-Text Articles in Physical Sciences and Mathematics

Precise Detection Of Injection Attacks On Concrete Systems, Clayton Whitelaw Nov 2015

Precise Detection Of Injection Attacks On Concrete Systems, Clayton Whitelaw

USF Tampa Graduate Theses and Dissertations

Injection attacks, including SQL injection, cross-site scripting, and operating system command injection, rank the top two entries in the MITRE Common Vulnerability Enumeration (CVE) [1]. Under this attack model, an application (e.g., a web application) uses some untrusted input to produce an output program (e.g., a SQL query). Applications may be vulnerable to injection attacks because the untrusted input may alter the output program in malicious ways. Recent work has established a rigorous definition of injection attacks. Injections are benign iff they obey the NIE property, which states that injected symbols strictly insert or expand noncode tokens in the output …


A Comparative Study Of Formal Verification Techniques For Authentication Protocols, Hernan Miguel Palombo Nov 2015

A Comparative Study Of Formal Verification Techniques For Authentication Protocols, Hernan Miguel Palombo

USF Tampa Graduate Theses and Dissertations

Protocol verification is an exciting area of network security that intersects engineering and formal methods. This thesis presents a comparison of formal verification tools for security protocols for their respective strengths and weaknesses supported by the results from several case studies. The formal verification tools considered are based on explicit model checking (SPIN), symbolic analysis (Proverif) and theorem proving (Coq). We formalize and provide models of several well-known authentication and key-establishment protocols in each of the specification languages, and use the tools to find attacks that show protocols insecurity. We contrast the modelling process on each of the tools by …


A Study On The Integration Of Multivariate Metocean, Ocean Circulation, And Trajectory Modeling Data With Static Geographic Information Systems For Better Marine Resources Management And Protection During Coastal Oil Spill Response – A Case Study And Gap Analysis On Northeastern Gulf Of Mexico Tidal Inlets, Richard Ray Knudsen Nov 2015

A Study On The Integration Of Multivariate Metocean, Ocean Circulation, And Trajectory Modeling Data With Static Geographic Information Systems For Better Marine Resources Management And Protection During Coastal Oil Spill Response – A Case Study And Gap Analysis On Northeastern Gulf Of Mexico Tidal Inlets, Richard Ray Knudsen

USF Tampa Graduate Theses and Dissertations

The Oil Pollution Act of 1990 requires the development of Regional and Area Contingency Plans. For more than 20 years, the State of Florida, under both the Department of Environmental Protection and the Florida Fish and Wildlife Commission, has worked closely with the U.S. Coast Guard and the National Oceanic and Atmospheric Administration to develop these plans for coastal and marine oil spill response. Current plans, developed with local, state and federal stakeholder input, use geographic information systems (GIS) data such as location and extent of sensitive ecological, wildlife, and human-use features (termed Environmental Sensitivity Index data), pre-defined protection priorities, …


Analysis Of Rheumatoid Arthritis Data Using Logistic Regression And Penalized Approach, Wei Chen Nov 2015

Analysis Of Rheumatoid Arthritis Data Using Logistic Regression And Penalized Approach, Wei Chen

USF Tampa Graduate Theses and Dissertations

In this paper, a rheumatoid arthritis (RA) medicine clinical dataset with an ordinal response is selected to study this new medicine. In the dataset, there are four features, sex, age,treatment, and preliminary. Sex is a binary categorical variable with 1 indicates male, and 0 indicates female. Age is the numerical age of the patients. And treatment is a binary categorical variable with 1 indicates has RA, and 0 indicates does not have RA. And preliminary is a five class categorical variable indicates the patient’s RA severity status before taking the medication. The response Y is 5 class ordinal variable shows …


Comparison Of Otolith-Based Growth Rates And Microchemistry In Red Drum Before, During, And After The Deepwater Horizon Oil Spill, Brock Charles Houston Nov 2015

Comparison Of Otolith-Based Growth Rates And Microchemistry In Red Drum Before, During, And After The Deepwater Horizon Oil Spill, Brock Charles Houston

USF Tampa Graduate Theses and Dissertations

Oil from the Deepwater Horizon blowout reached the Gulf of Mexico coast in the summer of 2010 and potentially exposed species living in those areas to toxic chemicals. The purpose of this study is to examine otoliths from Red Drum (Sciaenops ocellatus) for evidence of oil exposure that could be related to reduced growth rates. Because otolith growth and somatic growth are directly related, differences in annulus measurements can indicate differences in annual somatic growth, which is a good indicator of overall fish condition, and translates into changes in survival and lifetime reproductive potential. This study assessed variation …


Understanding Climate Change And Sea Level: A Case Study Of Middle School Student Comprehension And An Evaluation Of Tide Gauges Off The Panama Canal In The Pacific Ocean And Caribbean Sea, Juan Carlos Millan-Otoya Nov 2015

Understanding Climate Change And Sea Level: A Case Study Of Middle School Student Comprehension And An Evaluation Of Tide Gauges Off The Panama Canal In The Pacific Ocean And Caribbean Sea, Juan Carlos Millan-Otoya

USF Tampa Graduate Theses and Dissertations

The present study had two main objectives. The first was to determine the degree of understanding of climate change, sea level and sea level rise among middle school students. Combining open-ended questions with likert-scaled questions, we identified student conceptions on these topics in 86 students from 7th and 8th grades during 2012 and 2013 before and after implementing a Curriculum Unit (CU). Additional information was obtained by adding drawings to the open-ended questions during the second year to gauge how student conceptions varied from a verbal and a visual perspective. Misconceptions were identified both pre- and post-CU among …


The Development Of A Fluorescence-Based Reverse Flow Injection Analysis (Rfia) Method For Quantifying Ammonium At Nanomolar Concentrations In Oligotrophic Seawater, William Abbott Nov 2015

The Development Of A Fluorescence-Based Reverse Flow Injection Analysis (Rfia) Method For Quantifying Ammonium At Nanomolar Concentrations In Oligotrophic Seawater, William Abbott

USF Tampa Graduate Theses and Dissertations

The goal of this thesis was to adopt a reverse flow injection analysis (rFIA) technique to the fluorometric analysis of the reaction o-phthaldialdehyde (OPA) with ammonium, allowing accurate measurements of ammonium concentrations lower than the detection limit of the widely used indophenol blue (IPB) colorimetric method while accounting for the background fluorescence of seawater. Ammonium is considered an essential nutrient for primary productivity, especially in the nutrient depleted surface ocean where as the most reduced form of dissolved inorganic nitrogen, it is readily assimilated via metabolic pathways. Challenges in the quantification of ammonium require more sensitive analytical techniques for …


Influence Of Water Column Stratification And Nutrient Gradients On The Migratory Behavior Of The Red Tide Dinoflagellate, Karenia Brevis, Matthew Garrett Nov 2015

Influence Of Water Column Stratification And Nutrient Gradients On The Migratory Behavior Of The Red Tide Dinoflagellate, Karenia Brevis, Matthew Garrett

USF Tampa Graduate Theses and Dissertations

Diel vertical migration (DVM) can offer motile phytoplankton a competitive advantage over other phytoplankton species. DVM has been well documented in the harmful dinoflagellate, Karenia brevis; however, the extent to which changes in nutrient regimes and density stratification modify migration patterns has not been thoroughly investigated. A 2 m experimental column was constructed with sensors and sampling ports at four depths to obtain fluorescence and temperature measurements and discrete water samples. The environmental parameters of the experimental column represented temperature and nutrient conditions found on the West Florida Shelf (WFS), where Karenia blooms frequently occur. Results demonstrated a clear …


Geophysical Evidence For Mid-Crustal Magma Reservoirs In The Lassen Volcanic Region, California, Samantha Catherine Tavarez Nov 2015

Geophysical Evidence For Mid-Crustal Magma Reservoirs In The Lassen Volcanic Region, California, Samantha Catherine Tavarez

USF Tampa Graduate Theses and Dissertations

Regional-scale complete Bouguer gravity anomalies underlying the Lassen and Shasta -Medicine Lake regions in northern California and southern Oregon are associated with subduction of the Gorda plate beneath North America. These generally negative anomalies reflect where underplating has deepened to form the mantle wedge, and where subduction has given rise to a series of Quaternary volcanoes comprising the southernmost end of the Cascade range. Multiple conductive bodies were identified by Park and Ostos (2013) in their magnetotelluric (MT) study of the broader Lassen volcanic region. Their broadband and long period measurements were conducted along a 250 km profile spanning from …


Ensemble Learning Method On Machine Maintenance Data, Xiaochuang Zhao Nov 2015

Ensemble Learning Method On Machine Maintenance Data, Xiaochuang Zhao

USF Tampa Graduate Theses and Dissertations

In the industry, a lot of companies are facing the explosion of big data. With this much information stored, companies want to make sense of the data and use it to help them for better decision making, especially for future prediction. A lot of money can be saved and huge revenue can be generated with the power of big data. When building statistical learning models for prediction, companies in the industry are aiming to build models with efficiency and high accuracy. After the learning models have been developed for production, new data will be generated. With the updated data, the …


Synthesis, Characterization And Ferroelectric Properties Of Ln-Type Znsno3 Nanostructures, Corisa Kons Nov 2015

Synthesis, Characterization And Ferroelectric Properties Of Ln-Type Znsno3 Nanostructures, Corisa Kons

USF Tampa Graduate Theses and Dissertations

With increasing focus on the ill health and environmental effects of lead there is a greater push to develop Pb-free devices and materials. To this extent, ecofriendly and earth abundant LiNbO3-type ZnSnO3, a derivative of the ABO3 perovskite structure, has a high theoretically predicted polarization making it an excellent choice as a suitable alternative to lead based material such as PZT. In this work we present a novel synthesis procedure for the growth of various ZnSnO3 nanostructures by combined physical/chemical processes. Various ZnSnO3 nanostructures of different dimensions were grown from a ZnO:Al template …


Is Nubia Plate Rigid? A Geodetic Study Of The Relative Motion Of Different Cratonic Areas Within Africa., Mary Wambui Njoroge Nov 2015

Is Nubia Plate Rigid? A Geodetic Study Of The Relative Motion Of Different Cratonic Areas Within Africa., Mary Wambui Njoroge

USF Tampa Graduate Theses and Dissertations

The Nubia plate is normally considered to be a rigid plate and as such used in the realization of terrestrial reference frame. Gondwana breakup plate reconstruction, the Cameroon volcanic line, seismicity, and the morphology of the Okavango rift zone (ORZ) suggest the presence of internal deformation within the Nubia plate. To test this hypothesis, six different reference frames were developed from the velocity field of three individual regions (West, Central and South), and of different combinations of them (West+Central, South+Central, and Nubia as a whole). The residual velocities with respect to these references frame help us understand the presence of …


Operation And Monitoring Of Parabolic Trough Concentrated Solar Power Plant, Harsha Vardhan Amba Nov 2015

Operation And Monitoring Of Parabolic Trough Concentrated Solar Power Plant, Harsha Vardhan Amba

USF Tampa Graduate Theses and Dissertations

The majority of the power generated today is produced using fossil fuels,emitting carbon dioxide and other pollutants every second. Also, fossil fuels will eventually run out. For the increasing worldwide energy demand, the use f reliable and environmentally beneficial natural energy sources is one of the biggest challenges. Alongside wind and water, the solar energy which is clean, CO2-neutral and limitless, is our most valuable resource.

Concentrated solar power (CSP) is becoming one of the excellent alternative sources for the power industry. The successful implementation of this technology requires the efficient design of tracking and operation system of the CSP …


Evaluation Of Low-Cost Low Impact Development Practices In Southwest Florida For The Control Of Urban Runoff, Laura Kathren Rankin Nov 2015

Evaluation Of Low-Cost Low Impact Development Practices In Southwest Florida For The Control Of Urban Runoff, Laura Kathren Rankin

USF Tampa Graduate Theses and Dissertations

Stormwater management is required due to development and alteration of the natural environment. It is heavily regulated in Florida and at the national level. Over the last two decades, Low Impact Development (LID) has been promoted as a sustainable and environmentally friendly method of controlling urban runoff. Case studies, provided in Chapter 2, show that LIDs can restore watershed hydrology by balancing the water budget. The difference in runoff between pre-development and post-development appears to increase with soil perviousness. However, the potential for mitigating the impacts of urbanization through runoff reduction is also greater for pervious, sandy soils that dominate …


Land-Use & Water Quality In The Headwaters Of The Alafia River Watershed, Jaime Alison Swindasz Nov 2015

Land-Use & Water Quality In The Headwaters Of The Alafia River Watershed, Jaime Alison Swindasz

USF Tampa Graduate Theses and Dissertations

The objective of this study is to investigate land-use changes and water quality trends within the headwaters of the Alafia River watershed. Water quality data were obtained from the Environmental Protection Commission of Hillsborough County (EPCHC). Eleven water quality parameters selected for analysis included: temperature (˚C), dissolved oxygen (DO), percent saturation of DO, conductivity, pH, total phosphorous (TP), total nitrogen (TN), ammonium, chlorophyll-a (uncorrected), fecal coliforms, and enterococci. ArcMap® & SWFWMD data were used to map EPCHC sampling stations, calculate contributing watershed size, and determine land-use changes over the course of the sampling period; 17 stations were chosen for this …


In Situ Studies Of Limestone Dissolution In A Coastal Submarine Spring, Rachel Marie Schweers Nov 2015

In Situ Studies Of Limestone Dissolution In A Coastal Submarine Spring, Rachel Marie Schweers

USF Tampa Graduate Theses and Dissertations

Limestone dissolution in karst environments is likely due to geochemistry of the water, the actions of microbial communities, and the effect of water flow. We explored the rate of limestone dissolution and will examine here the microbial communities associated with the limestone. A conduit within the brackish cave, Double Keyhole Spring, on the coast of central west Florida was the site of the experiment. PVC pipes (5cm x 16cm) were filled with crushed limestone that was screened to a 1.9cm – 2.54cm size range. There were three treatments (5 replicates each): Control - sealed autoclaved controls with limestone and conduit …


Embedded System Design Of A Real-Time Parking Guidance System, Omkar Dokur Oct 2015

Embedded System Design Of A Real-Time Parking Guidance System, Omkar Dokur

USF Tampa Graduate Theses and Dissertations

The primary objective of this work is to design a parking guidance system to reliably detect entering/exiting vehicles to a parking garage in a cost-efficient manner. Existing solutions (inductive loops, RFID based systems, and video image processors) at shopping malls, universities, airports etc., are expensive due to high installation and maintenance costs. There is a need for a parking guidance system that is reliable, accurate, and cost-effective. The proposed parking guidance system is designed to optimize the use of parking spaces and to reduce wait times. Based on a literature review we identify that the ultrasonic sensor is suitable to …


Tailoring The Pore Environment Of Metal-Organic And Molecular Materials Decorated With Inorganic Anions: Platforms For Highly Selective Carbon Capture, Patrick Stephen Nugent Oct 2015

Tailoring The Pore Environment Of Metal-Organic And Molecular Materials Decorated With Inorganic Anions: Platforms For Highly Selective Carbon Capture, Patrick Stephen Nugent

USF Tampa Graduate Theses and Dissertations

Due to their high surface areas and structural tunability, porous metal-organic materials, MOMs, have attracted wide research interest in areas such as carbon capture, as the judicious choice of molecular building block (MBB) and linker facilitates the design of MOMs with myriad topologies and allows for a systematic variation of the pore environment. Families of MOMs with modular components, i.e. MOM platforms, are eminently suitable for targeting the selective adsorption of guest molecules such as CO2 because their pore size and pore functionality can each be tailored independently. MOMs with saturated metal centers (SMCs) that promote strong yet reversible …


Developing A Compiler For A Regular Expression Based Policy Specification Language, Cory Michael Juhlin Oct 2015

Developing A Compiler For A Regular Expression Based Policy Specification Language, Cory Michael Juhlin

USF Tampa Graduate Theses and Dissertations

Security policy specification languages are a response to today's complex and vulnerable software climate. These languages allow an individual or organization to restrict and modify the behavior of third-party applications such that they adhere to the rules specified in the policy. As software grows in complexity, so do the security policies that govern them. Existing policy specification languages have not adapted to the growing complexity of the software they govern and as a result do not scale well, often resulting in code that is overly complex or unreadable. Writing small, isolated policies as separate modules and combining them is known …


Saharan Air Layer Dust Loading: Effects On Convective Strength In Tropical Cloud Clusters, Randall J. Hergert Oct 2015

Saharan Air Layer Dust Loading: Effects On Convective Strength In Tropical Cloud Clusters, Randall J. Hergert

USF Tampa Graduate Theses and Dissertations

Numerous factors play a role in the development and maintenance of North Atlantic tropical cyclones as they originate and cross the Main Development Region. These factors include sea-surface temperatures (SSTs), relative humidity, vertical wind shear, etc. One key player in many of these factors is the Saharan Air Layer (SAL) which has been a source for study for nearly five decades.

The interplay between dust loading within the SAL and the development of African Easterly Waves (AEWs) has been repeatedly noted in many of the studies in this field. The cumulative indirect effect of the dust on AEWs however remains …


Blindcanseeql: Improved Blind Sql Injection For Db Schema Discovery Using A Predictive Dictionary From Web Scraped Word Based Lists, Ryan Wheeler Oct 2015

Blindcanseeql: Improved Blind Sql Injection For Db Schema Discovery Using A Predictive Dictionary From Web Scraped Word Based Lists, Ryan Wheeler

USF Tampa Graduate Theses and Dissertations

SQL Injections are still a prominent threat on the web. Using a custom built tool, BlindCanSeeQL (BCSQL), we will explore how to automate Blind SQL attacks to discover database schema using fewer requests than the standard methods, thus helping avoid detection from overloading a server with hits. This tool uses a web crawler to discover keywords that assist with autocompleting schema object names, along with improvements in ASCII bisection to lower the number of requests sent to the server. Along with this tool, we will discuss ways to prevent and protect against such attacks.


A Bat-Guano-Derived Δ15N And Δ13C Record Of Paleoenvironmental Change: Zidită Cave, Romania, Daniel Martin Cleary Oct 2015

A Bat-Guano-Derived Δ15N And Δ13C Record Of Paleoenvironmental Change: Zidită Cave, Romania, Daniel Martin Cleary

USF Tampa Graduate Theses and Dissertations

Because nitrogen isotopes are fractionated along the soil-plant-insect-bat-guano pathway, it may be possible to reconstruct environmental and climatic changes reflected in the nitrogen isotopic composition of guano. A 1.5-m core of bat guano from Zidită Cave (western Romania) provides a record of climatic and anthropogenic influence on the regional nitrogen cycle and paleoenvironmental controls on nitrogen transforming processes. Increasing and decreasing trends of nitrogen isotopic composition (δ15N values) correspond well with changes in the influence of farming practices, deforestation, and forest expansion. These influences likely had a significant effect on the openness of the nitrogen cycle, resulting in …


Informing The Design And Deployment Of Health Information Technology To Improve Care Coordination, Diego A. Martinez Oct 2015

Informing The Design And Deployment Of Health Information Technology To Improve Care Coordination, Diego A. Martinez

USF Tampa Graduate Theses and Dissertations

In the United States, the health care sector is 20 years behind in the use of information technology to improve the process of health care delivery as compared to other sectors. Patients have to deliver their data over and over again to every health professional they see. Most health care facilities act as data repositories with limited capabilities of data analysis or data exchange. A remaining challenge is, how do we encourage the use of IT in the health care sector that will improve care coordination, save lives, make patients more involved in decision-making, and save money for the American …


Dissolved Nutrient Distributions In The Gulf Of Mexico Following The Deepwater Horizon Oil Spill, Ashley Ann Parks Oct 2015

Dissolved Nutrient Distributions In The Gulf Of Mexico Following The Deepwater Horizon Oil Spill, Ashley Ann Parks

USF Tampa Graduate Theses and Dissertations

The Deepwater Horizon (DWH) oil spill in the Gulf of Mexico (GoM) in the spring of 2010 introduced 4.4 million of barrels of oil to the ecosystem. Some biodegradation of the oil occurs when microorganisms, particularly bacteria, metabolize the oil as a carbon source. During this process, the microbes also require nutrients for energy. An introduction of oil at this magnitude has the ability to induce large blooms of microbes, which in turn can affect nutrient concentrations. Microbial petroleum degradation decreases nutrient concentrations, whereas the microbial assimilation and decay of organic matter increase nutrient concentrations. This study assessed whether any …


Millennial-Scale Variability Of A Major East Antarctic Outlet Glacier During The Last Glaciation, Michelle Guitard Oct 2015

Millennial-Scale Variability Of A Major East Antarctic Outlet Glacier During The Last Glaciation, Michelle Guitard

USF Tampa Graduate Theses and Dissertations

Ongoing retreat of Antarctica’s marine-based glaciers is associated with warm (~2° C) modified Circumpolar Deep Water intrusion onto the continental shelf, suggesting that Southern Ocean temperatures may influence Antarctic ice sheet stability. Understanding past cryosphere response to environmental forcing is crucial to modeling future ice sheet behavior. Of particular interest is the response of the East Antarctic Ice Sheet (EAIS), which stands to contribute ~20 m to global sea level. However, marine sediment sequences recording timing and variability of EAIS fluctuations through the last major climate shift, the Last Glacial Maximum (LGM), are either missing from the margin or have …


Ocean Forcing Of Quaternary East Antarctic Ice Sheet Evolution: An Ice-Proximal Sedimentary Perspective, Michelle E. Guitard Oct 2015

Ocean Forcing Of Quaternary East Antarctic Ice Sheet Evolution: An Ice-Proximal Sedimentary Perspective, Michelle E. Guitard

USF Tampa Graduate Theses and Dissertations

Antarctica and the Southern Ocean play a critical role in Earth’s climate system. Antarctica’s ice sheets contain enough ice to raise global sea level by ~58 m, and the Southern Ocean distributes climate signals and nutrients to the major ocean basins and the deep ocean. Antarctica’s largest ice sheet, the East Antarctic Ice Sheet (EAIS), was considered stable compared to those in West Antarctica and the Antarctic Peninsula because it was thought to be grounded above sea level. However, subglacial topography now reveals vast submarine basins and measurements of ice velocity in the Pacific sector indicate marine-terminating outlet glacier thinning …


The Role Of Community Participation In Water Production And Management: Lessons From Sustainable Aid In Africa International Sponsored Water Schemes In Kisumu, Kenya, Erick Oniango Ananga Oct 2015

The Role Of Community Participation In Water Production And Management: Lessons From Sustainable Aid In Africa International Sponsored Water Schemes In Kisumu, Kenya, Erick Oniango Ananga

USF Tampa Graduate Theses and Dissertations

Few studies have attempted to determine the tenability of Community Participation (CP) theory is explicating Water Production and Management dynamics in Urban Informal Settlements. Consequently, several gaps exist in knowledge of the value of this important theory for efforts to improve water service delivery in such settlements. The main purpose of this study is to contribute to efforts addressed to filling these gaps. Four water schemes established by Sustainable Aid in Africa International in partnership with different communities in the informal neighborhoods of Kisumu Kenya are used as empirical referent. The study is guided by the following three Research Questions; …


Field Observations And Novel Methodologies For Carbon System Assessments In Coastal Waters, Bo Yang Sep 2015

Field Observations And Novel Methodologies For Carbon System Assessments In Coastal Waters, Bo Yang

USF Tampa Graduate Theses and Dissertations

Coastal zones receive massive terrestrial inputs of nutrients and organic matter, and play an important role in biogeochemical cycles. The interactions of river inputs, ocean currents, atmospheric exchanges, anthropogenic influences, and biologically active ecosystems make CO2 system studies in coastal waters highly challenging. This work focuses on improving our understanding of the CO2 system in coastal waters through (1) development of a new methodology for measurements of CO2 system parameters in the field; (2) observations of large spatial and temporal CO2 system variations in coastal waters; and (3) characterization of the influence of organics on CO …


Bio-Photoelectrochemical Solar Cells Incorporating Reaction Center And Reaction Center Plus Light Harvesting Complexes, Houman Yaghoubi Sep 2015

Bio-Photoelectrochemical Solar Cells Incorporating Reaction Center And Reaction Center Plus Light Harvesting Complexes, Houman Yaghoubi

USF Tampa Graduate Theses and Dissertations

Harvesting solar energy can potentially be a promising solution to the energy crisis now and in the future. However, material and processing costs continue to be the most important limitations for the commercial devices. A key solution to these problems might lie within the development of bio-hybrid solar cells that seeks to mimic photosynthesis to harvest solar energy and to take advantage of the low material costs, negative carbon footprint, and material abundance. The bio-photoelectrochemical cell technologies exploit biomimetic means of energy conversion by utilizing plant-derived photosystems which can be inexpensive and ultimately the most sustainable alternative. Plants and photosynthetic …


Bayesian Inference On Longitudinal Semi-Continuous Substance Abuse/Dependence Symptoms Data, Dongyuan Xing Sep 2015

Bayesian Inference On Longitudinal Semi-Continuous Substance Abuse/Dependence Symptoms Data, Dongyuan Xing

USF Tampa Graduate Theses and Dissertations

Substance use data such as alcohol drinking often contain a high proportion of zeros. In studies examining the alcohol consumption in college students, for instance, many students may not drink in the studied period, resulting in a number of zeros. Zero-inflated continuous data, also called semi continuous data, typically consist of a mixture of a degenerate distribution at the origin (zero) and a right-skewed, continuous distribution for the positive values. Ignoring the extreme non-normality in semi-continuous data may lead to substantially biased estimates and inference. Longitudinal or repeated measures of semi-continuous data present special challenges in statistical inference because of …