Digital Commons Network^™

Broad-Band Space Conservative On Wafer Network Analyzer Calibrations With More Complex Solt Definitions, Sathya Padmanabhan

USF Tampa Graduate Theses and Dissertations

An improved Short-Open-Load-Thru (SOLT) on-wafer vector network calibration method for broad-band accuracy is proposed. Accurate measurement of on-wafer devices over a wide range of frequency, from DC to high frequencies with a minimum number of space conservative standards has always been desirable. Therefore, the work is aimed at improving the existing calibration methods and suggesting a best "practice" strategy that could be adopted to obtain greater accuracy with a simplified procedure and calibration set.

Quantitative and qualitative comparisons are made to the existing calibration techniques. The advantages and drawbacks of each calibration are analyzed. Prior work done at the University …

High Level Synthesis Of An Image Processing Algorithm For Cancer Detection, Anuleka Bilhanan

USF Tampa Graduate Theses and Dissertations

There is a crucial need for real time detection and diagnosis in digital mammography. To date, most computer aided analysis applications are software driven and normally require long processing times. Digital filtering is often the initial stage in processing mammograms for both automated detection and tissue characterization, which relies on Fourier analysis. In this research the main objective is to lay the groundwork for converting software driven mammography applications to hardware implementations by using Application-Specific Integrated Circuits (ASICs). The long-term goal is to increase processing speed. This research focuses on achieving the main objective by using one specific mammographic image …

Core Issues In Graph Based Perceptual Organization: Spectral Cut Measures, Learning, Padmanabhan Soundararajan

USF Tampa Graduate Theses and Dissertations

Grouping is a vital precursor to object recognition. The complexity of the object recognition process can be reduced to a large extent by using a frontend grouping process. In this dissertation, a grouping framework based on spectral methods for graphs is used. The objects are segmented from the background by means of an associated learning process that decides on the relative importance of the basic salient relationships such as proximity, parallelism, continuity, junctions and common region. While much of the previous research has been focussed on using simple relationships like similarity, proximity, continuity and junctions, this work differenciates itself by …

Adaptive Digital Predistortion Linearizer For Power Amplifiers In Military Uhf Satellite, Jayanti Patel

USF Tampa Graduate Theses and Dissertations

The existing UHF Satellite Communications (SATCOM) transponders used for military applications use efficient, saturated power amplifiers, which provide one earth-coverage antenna beam. The amplifier is dedicated to small frequency band and only handles a few carriers simultaneously.

The communications capacity needed to support future military forces on the move will require satellite payload power amplifiers to support hundreds of channels simultaneously, with the channels spread over the entire military UHF SATCOM band. To meet the capacity requirements and simultaneously meet the out-of-band emission, power amplifiers will have to be highly linear. The high-efficiency, ultra-linear power amplifier architecture proposed to support …

High Level Vhdl Modeling Of A Low-Power Asic For A Tour Guide, Umadevi Kailasam

USF Tampa Graduate Theses and Dissertations

We present the high level (VHDL) modeling and high level synthesis of an ASIC (TOUR NAVIGATOR) for a portable hand held device - a tour guide. The tour guide is based on location-aware mobile computing, which gives the information of the current location to the user. The TOUR NAVIGATOR designed in this work is interfaced with off-the-shelf components to realise the tour guide system. The current location is given by an on-board GPS receiver chip. The TOUR NAVIGATOR is a search and play module which interfaces with the flash memory, GPS receiver and the audio codec.

The functionality of the …

Ammonia Flux At The Air/Water Interface Of Tampa Bay, Constance Anne Mizak

USF Tampa Graduate Theses and Dissertations

An ammonia emissions inventory discovered that 90% of the ammonia emitted from Pinellas, Hillsborough, and Polk counties, originated from the latter two counties. This finding is significant and suggests that a substantial portion of the ammonia deposited to Tampa Bay is transported with easterly air masses.

Ammonia and ammonium concentrations at the coastal Gandy Bridge site were seasonally and diurnally consistent, but the rural Sydney site showed greater variability. It was determined that wind direction was the most influential parameter affecting the Gandy Bridge site, which supports the hypothesis that an advection of ammonia from the east is a major …

Benefit Of Staged Cooling In Shrink Fitted Composite Cylinders, Nathaniel Oren Collier

USF Tampa Graduate Theses and Dissertations

To assemble the fulcrum of bascule bridges, a trunnion is immersed into liquid nitrogen so that it can be shrunk fit into the hub. This is followed by immersing the resulting trunnion-hub assembly into liquid nitrogen so that it can be then shrunk fit into the girder. On one occasion in Florida, when the trunnion-hub assembly was put into liquid nitrogen, development of cracks on the hub was observed. Experimental and numerical studies conducted since 1998 at University of South Florida show that the cracking took place due to combination of high interference stresses in the trunnion-hub assembly, low fracture …

The Interaction Between Victim Race And Gender On Capital Sentencing Outcomes: An Exploration Of Previous Research, Amy Reckdenwald

USF Tampa Graduate Theses and Dissertations

This study is an exploration and extension of previous research on the interactive effects of victim-race and victim-gender on death sentence outcomes. Williams and Holcomb's (2004) study suggests that an interactive effect exists between victim-race and victim-gender on Ohio death sentencing outcomes, such that killers of White women are especially singled out for capital punishment. The current study analyzes a sample of death eligible cases at the trial level in North Carolina to determine if Williams & Holcomb's findings hold up for a different sample of cases and in a different state. Logistic regression is used to determine if there …

Development Of Cadmium Selenide As An Absorber Layer For Tandem Solar Cells, Sathyaharish Jeedigunta

USF Tampa Graduate Theses and Dissertations

Cadmium Selenide is a binary compound. It has a band gap of 1.7 eV. This is one of the suitable materials for an absorber layer in the top cell of a tandem solar cell. CIGS with a low Gallium content has a band gap of 1 eV suits well as an absorber layer for the bottom cell. CIGS cells have already attained an efficiency of 15% [1,2]. Since years, research has been done in developing the bottom cell. The results of the bottom cell are promising. So the fabrication of an efficient top cell in a tandem solar cell is …

Supramolecular Metal-Organic And Organic Materials, Elisabeth Rather

USF Tampa Graduate Theses and Dissertations

The rational design of functional solids based upon the development of strategies for controlling intermolecular interactions and structural arrangement of simple molecular building units, represents a salient feature in the context of supramolecular chemistry and crystal engineering. Consideration of chemical functionality, geometrical capability and knowledge of the interplay between two or more sets of supramolecular interactions specific of preselected chemical components will facilitate further extension of crystal engineering towards the construction of supramolecular materials possessing valuable properties.

Calixarenes represent excellent building blocks for the design of solid-state architectures, in particular calix-4-arenes crystallize easily and the introduction of a wide range …

Alternative Formulations Of Joint Model Systems Of Departure Time Choice And Mode Choice For Non-Work Trips, Constantinos A. Tringides

USF Tampa Graduate Theses and Dissertations

Modeling travel demand by time of day is gaining increasing attention in travel demand forecasting practice. This is because time of day choice has important implications for mode choice and for quantifying potential modal and time of day shifts in response to traffic congestion and peak period travel demand management strategies. In this context, understanding the causal relationship between time of day (departure time) choice and mode choice behavior would be useful in the development of time of day based travel demand modeling systems both within the four-step modeling paradigm and within newer tour-based and activity-based microsimulation paradigms. This thesis …

Investigation Of Oxide Thickness Dependence Of Fowler-Nordheim Parameter B, Shashank Bharadwaj

USF Tampa Graduate Theses and Dissertations

During recent years the thickness of the gate oxide has been reduced considerably. The progressive miniaturization of devices has caused several phenomena to emerge such as quasi-breakdown, direct tunneling and stress induced leakage currents. Such phenomena significantly modify the performance of the scaled-down MOSFETs. As a part of this research work, an effort has been made to study the performance and characteristics of the thin Gate oxide for MOSFETs and Tunnel Oxide for Floating Gate (FG) MOS devices. The exponential dependence of tunnel current on the oxide-electric field causes some critical problems in process control. A very good process control …

Development Of Structural Equations Models Of Statewide Freight Flows, Siva S. Jonnavithula

USF Tampa Graduate Theses and Dissertations

The modeling of freight travel demand has gained increasing attention in the recent past due to the importance of efficient and safe freight transportation to regional economic growth. Despite the attention paid to the modeling of freight travel demand, advances in modeling methods and the development of practical tools for forecasting freight flows have been limited. The development of freight demand models that incorporate the behavioral aspects of freight demand face significant hurdles, partially due to the data requirements, which are a consequence of the inherent complexity of the mechanisms driving freight demand. This research attempts to make a contribution …

Indium Oxide As A High Resistivity Buffer Layer For Cdte/Cds Thin Film Solar Cells, Umamaheswari Balasubramanian

USF Tampa Graduate Theses and Dissertations

Transparent conductive oxides are an essential part of technologies that require both large-area electrical contact and optical access in the visible portion of the light spectrum.

SnO₂ doped with Fluorine (SnO₂: F) and In₂O₃ doped with tin (ITO) are the most popular choices of front contacts for CdTe solar cells. In this thesis, CdS/CdTe devices were fabricated with SnO₂: F (MOCVD) and ITO (sputtering) as front contacts without a high resistivity (resistivity relatively greater than front contact) buffer layer. The device characteristics of these devices were low but improved considerably after the …

Synthesis And Characterization Of Potential Drug Delivery Systems Using Nonionic Surfactant “Niosome”, Sukit Leekumjorn

USF Tampa Graduate Theses and Dissertations

Niosomes are synthetic microscopic vesicles consisting of an aqueous core enclosed in a bilayer consisting of cholesterol and one or more nonionic surfactants. They are made of biocompatible, biodegradable, non-toxic, non-immunogenic and non-carcinogenic agents which form closed spherical structures (self assembly vesicles) upon hydration. With high resistance to hydrolytic degradation, niosomes are capable of entrapping many kinds of soluble drugs while exhibiting greater vesicle stability and longer shelf life.

In this work, a potential drug delivery system has been designed, synthesized and characterized. For the synthesis of niosomes, a hydration process was developed with varying design parameters such as mass …

A Vhdl Implemetation Of The Advanced Encryption Standard-Rijndael Algorithm, Rajender Manteena

USF Tampa Graduate Theses and Dissertations

The National Institute of Standards and Technology (NIST) has initiated a process to develop a Federal information Processing Standard (FIPS) for the Advanced Encryption Standard (AES), specifying an Advanced Encryption Algorithm to replace the Data Encryption standard (DES) the Expired in 1998. NIST has solicited candidate algorithms for inclusion in AES, resulting in fifteen official candidate algorithms of which Rijndael was chosen as the Advanced Encryption Standard.

The Advanced Encryption Standard can be programmed in software or built with pure hardware. However Field Programmable Gate Arrays (FPGAs) offer a quicker, more customizable solution. This research investigates the AES algorithm with …

The Social Construction Of Workplace "Diversity", Brenda G. Shawver

USF Tampa Graduate Theses and Dissertations

This is a study of "workplace diversity" from a social constructionist perspective. The perspective holds that while human meaning is socially created, it is the social order which gives us resources for making this meaning. There is much literature about workplace diversity from objectivist standpoints that takes for granted the term "diversity." What is missing is a comprehensive understanding of diversity: what does this term mean? What does it conceal? I attempt to contribute to a better understanding of diversity by interrogating its construction in popular culture.

I analyze the content of an advertising supplement called "Diversity Works," published in …

Synthesis Of Nanoscale Structures In Single Crystal Silicon Carbide By Electron Beam Lithography, Jay A. Bieber

USF Tampa Graduate Theses and Dissertations

Nanostructures were formed on diced specimens of several silicon carbide polytypes and silicon using electron beam lithography. A general introduction to nanostructure synthesis and electron beam lithography,are presented. A scanning electron microscope was retrofitted with a commercially available electron beam lithography package and an electrostatic beam blanker to permit nanoscale lithography to be performed.

A process was first developed and optimized on silicon substrates to expose, poly-methyl-methacrylate (PMMA) resist with an electron beam to make nanoscale nickel masks for reactive ion etching. The masks consist of an array of nickel dots that range in size from 20 to 100 nm …

Effects Of Two-Way Left-Turn Lane On Roadway Safety, Haolei Peng

USF Tampa Graduate Theses and Dissertations

Two-way left-turn lane (TWLTL) is one of the common median treatments on the roadway. It is found that a number of crashes reported in Florida State are related to TWLTLs. This research focused on evaluating the effect of TWLTLs on these crashes by using the statistical crash prediction model that can estimate the expected number of crashes on TWLTLs. The crash database for analysis was extracted from the Florida Traffic Crash Database based on the TWLTL section list provided by FDOT and combined with some traffic characteristics. It consisted of totally 1688 sample sections within a three-year period from 1996 …

Laboratory Statnamic Testing, Michael Jeffrey Stokes

USF Tampa Graduate Theses and Dissertations

Despite advancements in the analysis of statnamic load testing data, there exists uncertainty with underlying procedural assumptions. Two such assumptions are that the system mass and soil-related damping coefficient remain constant throughout the loading event. These assumptions are the culprit of aberrant predictions of the static capacity at small displacements when the overall displacement is large. An exploration of the assumptions may validate prior existing test results as well as solidify the current analysis process. However, an exploration could also reveal an overestimation or underestimation of portions of the predicted static load responses.

The testing program outlined herein consists of …

Prediction Of Commuter Choice Behavior Using Neural Networks, Aaron L. Gregory

USF Tampa Graduate Theses and Dissertations

In order to reduce air pollution and reduce the amount of traffic on highways in the western United States, certain states have set up worksite trip reduction programs. Employers in these states must comply with worksite trip reduction laws and submit trip reduction plans to their respective regulatory agency each year. These plans are currently evaluated manually, and are either rejected or accepted by the agency. There are two major flaws in this system; the first is the amount of time required by the agency to review a plan could be a matter of months, and the second is that …

A Model To Create Bus Timetables To Attain Maximum Synchronization Considering Waiting Times At Transfer Stops, Anitha Eranki

USF Tampa Graduate Theses and Dissertations

Due to the steady increased in public transportation demand, there is a need to provide more desirable and user-friendly transit systems. Typically, the public transportation timetables are modeled as an assignment problem, which often has objectives such as reducing the cost of operation, minimizing waiting time between transfer points or improving the quality of performance. This research considers the problem of developing synchronized timetables for bus transit systems with fixed routes when a waiting time limit exist at each transfer stops, for the passengers making connections. The objective of this research is to have maximum number of simultaneous arrivals.

Different …

Development Of An Instrumented Mannequin For Training Of Caregivers In Safe Patient Handling And Movement, Oneida Dugarte Westhoff

USF Tampa Graduate Theses and Dissertations

A common problem associated with patient handling is the risk of bodily injury due to acute or cumulative trauma. The objective of this research was to develop an integrated solution, using commercially available components, to help health care providers handle patients in a safe manner. The objective was achieved by retrofitting a mannequin with flex sensors, electrogoniometers, pressure sensors, and photocells. The sensors were capable of quantifying angular displacement, skin pressure distribution and undignified exposure. All of these variables were monitored by a computer-based data acquisition system. The design of this integrated system was implemented using National Instruments LabView software, …

A Learning Approach To Obtain Efficient Testing Strategies In Medical Diagnosis, Saif Fakih

USF Tampa Graduate Theses and Dissertations

Determining the most efficient use of diagnostic tests is one of the complex issues facing the medical practitioners. It is generally accepted that excessive use of tests is common practice in medical diagnosis. Many tests are performed even though the incremental knowledge gained does not affect the course of diagnosis. With the soaring cost of healthcare in the US, there is a critical need for cutting costs of diagnostic tests, while achieving a higher level of diagnostic accuracy. Various decision making tools assisting physicians in diagnosis management have been presented to the literature. One such method, called analytical hierarchy process, …

Analysis Of How Mobile Robots Fail In The Field, Jennifer Carlson

USF Tampa Graduate Theses and Dissertations

The considerable risk to human life associated with modern military operations in urban terrain (MOUT) and urban search and rescue (USAR) has led professionals in these domains to explore the use of robots to improve safety. Recent studies on mobile robot use in the field have shown a noticeable lack of reliability in real field conditions. Improving mobile robot reliability for applications such as USAR and MOUT requires an understanding of how mobile robots fail in field environments.

This paper provides a detailed investigation of how ground-based mobile robots fail in the field. Forty-four representative examples of failures from 13 …

Improved Current-Voltage Methods For Rf Transistor Characterization, Charles Passant Baylis Ii

USF Tampa Graduate Theses and Dissertations

In the development of a nonlinear transistor model, several measurements are used to extract equivalent circuit parameters. The current-voltage (IV) characteristic of a transistor is one of the measurement data sets that allows the nonlinear model parameters to be extracted. The accuracy of the IV measurement greatly influences the accuracy of the large-signal model.

Numerous works have reported the inadequacy of traditional static DC IV measurements to accurately predict radio-frequency (RF) behavior for many devices. This inaccuracy results from slow processes in the device that do not have time to completely respond to the quick changes in terminal conditions when …

Brain Tumor Target Volume Determination For Radiation Therapy Treatment Planning Through The Use Of Automated Mri Segmentation, Gloria Patrika Mazzara

USF Tampa Graduate Theses and Dissertations

Radiation therapy seeks to effectively irradiate the tumor cells while minimizing the dose to adjacent normal cells. Prior research found that the low success rates for treating brain tumors would be improved with higher radiation doses to the tumor area. This is feasible only if the target volume can be precisely identified. However, the definition of tumor volume is still based on time-intensive, highly subjective manual outlining by radiation oncologists. In this study the effectiveness of two automated Magnetic Resonance Imaging (MRI) segmentation methods, k-Nearest Neighbors (kNN) and Knowledge-Guided (KG), in determining the Gross Tumor Volume (GTV) of brain tumors …

Fault Tolerant Design Verification Through The Use Of Laser Fault Injection, Paris D. Wiley

USF Tampa Graduate Theses and Dissertations

Laser Fault Injection (LFI) testing has been demonstrated to be a useful tool in the prediction of single event upset rates in microcircuits. In addition LFI has contributed to the basic understanding of the mechanisms that cause single event upsets. However, very little research has been performed on the viability of LFI as a tool for verifying fault tolerant designs incorporated in ASICs, FPGAs, microprocessors and embedded systems. Current fault tolerant design verification techniques such as simulation and test have several significant limitations that prevent the complete verification of a fault tolerant design. However, LFI possesses spatial, temporal and financial …

Longshore Sediment Transport From Northern Maine To Tampa Bay, Florida: A Comparison Of Longshore Field Studies To Relative Potential Sediment Transport Rates Derived From Wave Information Study Hindcast Data, Joseph F. Van Gaalen

USF Tampa Graduate Theses and Dissertations

This paper examines the regional longshore sediment transport pattern of the seaward coast of the United States and Gulf of Mexico from northern Maine to Tampa Bay, Florida. From previous studies it is known that along the coast there are variations in direction of sediment transport known as nodal zones as well as variations in sediment transport rate. Wave Information Study (WIS) hindcast data for the interval 1976 through 1995 (United States Army Corps of Engineers, 2003) provide a spatially continuous model of the regional longshore current directions in the study area.

In chapter one, all available published field studies …

Study Of Cu Free Back Contacts To Thin Film Cdte Solar Cells, Vijay Viswanathan

USF Tampa Graduate Theses and Dissertations

The goals of this project are study Cu free back contact alternatives for CdS/CdTe thin film solar cells, and to research dry etching for CdTe surface preparation before contact application. In addition, an attempt has been made to evaluate the stability of some of the contacts researched. The contacts studied in this work include ZnTe/Cu₂Te, Sb₂Te₃, and Ni-P alloys.

The ZnTe/Cu₂Te contact system is studied as basically an extension of the earlier work done on Cu₂Te at USF. RF sputtering from a compound target of ZnTe and Cu₂Te …