Digital Commons Network^™

Influence Of The So3 Content Of Cement On The Durability And Strength Of Concrete Exposed To Sodium Sulfate Environment, Amin A. Hanhan

USF Tampa Graduate Theses and Dissertations

The objective of this investigation was to assess the influence of the SO₃ content on the durability and strength of portland cement.

Four portland cements were used in this study. The cements had a variable tricalcium silicate, tricalcium aluminate, and alkali contents, as well as differences in the amount and form of calcium sulfates. The SO₃ content of the cements was increased by replacing part of the cement by gypsum according to ASTM C 452-95.

Mortar bars and cubes were prepared for the as-received as well as for the cements with an SO₃ content of 3.0% and …

A Radial Basis Neural Network For The Analysis Of Transportation Data, David P. Aguilar

USF Tampa Graduate Theses and Dissertations

This thesis describes the implementation of a Radial Basis Function (RBF) network to be used in predicting the effectiveness of various strategies for reducing the Vehicle Trip Rate (VTR) of a worksite. Three methods of learning were utilized in training the Gaussian hidden units of the network, those being a) output weight adjustment using the Delta rule b) adjustable reference vectors in conjunction with weight adjustment, and c) a combination of adjustable centers and adjustable sigma values for each RBF neuron with the Delta rule. The justification for utilizing each of the more advanced levels of training is provided using …

Microstructure And Magnetism In Ferrite-Ferroelectric Multilayer Films, Natalie A. Frey

USF Tampa Graduate Theses and Dissertations

Composite magneto-dielectric materials have been investigated over the years because of their potential applications in RF and microwave devices as the dielectric constant and permeability can be individually changed in these materials. In the recent past, there is a renewed interest in systems classified as ferroelectromagnets or multiferroics, which possess simultaneous ferroelectric and magnetic ordering as well as interesting magnetoelastic phenomena. In all these ferrite-ferroelectric materials, the coupling between the permeability (μ) of the magnetically ordered phase and permittivity (e) of the ferroelectric phase make them attractive candidates for multifunctional applications.

Ba_0.5Sr_0.5TiO₃ (BSTO) is a …

Protecting Biscayne: An Analysis Of Strategies For The Protection Of Biscayne National Park, Janell M. Harvey

USF Tampa Graduate Theses and Dissertations

Biscayne National Park is located off the southeast coast of Florida and attracts approximately half a million visitors annually. Managers of Biscayne National Park are proposing a new General Management Plan (GMP) in order to update the recreational and commercial use of resources in the park. A Fishery Management Plan (FMP) is also being drafted simultaneously in conjunction with the Florida Fish and Wildlife Conservation Commission in order to address concerns associated with management of fish stocks within the park.

The proposed plan alternatives of the GMP and the recommendations of the FMP were developed in response to the negative …

Linearity Optimization Of Power Transistors Utilizing Harmonic Terminations, Ravi Kumar Varanasi

USF Tampa Graduate Theses and Dissertations

This thesis focuses on the characterization and optimization of microwave power transistors using a commercial on-wafer harmonic load pull system. Specific attention is paid to the output tuning of the second harmonic impedance presented to the device. The ability to quantify the level of accuracy in a load pull system is explored by using various calibration validation methods, including a method called Delta-Gt. In this work experiments and simulation comparisons are described for three different device technologies, namely GaAs pHEMT, GaAs HJFET and InGaP HBT. Externally supplied non-linear models were used for the simulations and these were exercised and compared …

Applying The Wrapper Approach For Auto Discovery Of Under-Sampling And Over-Sampling Percentages On Skewed Datasets, Ajay D. Joshi

USF Tampa Graduate Theses and Dissertations

Machine learning applications are plagued by the imbalance observed among the class sizes in many real world datasets. A dataset is said to be skewed or imbalanced when its classes are very unequally represented. A naïve classifier learned from these skewed datasets is always biased towards the majority classes which constitute a major percentage of the samples in the dataset. As a result the accuracy on the minority classes is hampered. In many real world applications like network intrusion detection, cancer detection from mammography images, etc. the events of interest are very rare and the cost of not detecting these …

Limitations Of The Advection-Diffusion Equation For Modeling Tephra Fallout: 1992 Eruption Of Cerro Negro Volcano, Nicaragua, Kristin Terese Martin

USF Tampa Graduate Theses and Dissertations

Detailed mapping and granulometric analyses of the 1992 Cerro Negro tephra blanket reveal remarkable departures from the expected distribution of tephra. Isomass maps show that the major axis of dispersion for the eruption was to the SW of the cone and that the coarser-grained particles, ranging from -4.0 -- 1.0 f, were deposited primarily along the major axis of dispersion with deposits thinning off of the axis. Comparable isomass maps for finer-grained particles, 1.5 - 3.5 f, show that these particles were primarily deposited along the edges of the deposit, off of the major axis of dispersion. Advection-diffusion models for …

Prehistoric Shell Artifacts From The Apalachicola River Valley Area, Northwest Florida, Eric Eyles

USF Tampa Graduate Theses and Dissertations

With this thesis, I aim to fill a gap in our knowledge of shell artifacts from the northwest part of the state of Florida. It represents a first look at the range of shell artifacts in the collections of the University of South Florida (USF) obtained during the ongoing program of archaeological investigations in the Apalachicola Valley and surrounding region. There are 46 sites in the study area that have been identified as yielding shell artifacts, of which samples from 27 sites are curated in the USF Archaeology Laboratory. The proposed typology is based on an analysis of over 2300 …

Development Of A Solid Electrolyte For Hydrogen Production, Kiran Sampat Gaikwad

USF Tampa Graduate Theses and Dissertations

Electrolytic cells convert chemical energy directly into electrical energy cleanly and efficiently. An integral component of a fuel cell and an electrolytic cell is the electrolyte, a material that conducts ions. Liquid electrolytes can be aqueous as in the phosphoric acid and alkaline fuel cells, or molten, as in the molten carbonate fuel cells. A solid electrolyte is preferable because it allows sturdier, more efficient and corrosion resistant systems to be built.

The main objective of this work is to develop a solid electrolyte for hydrogen production by electrolysis of hydrogen sulfide. Barium Hydrogen Phosphate, Barium Dihydrogen Phosphate, Cesium Hydrogen …

Real Delay Graphical Probabilistic Switching Model For Vlsi Circuits, Vivekanandan Srinivasan

USF Tampa Graduate Theses and Dissertations

Power optimization is a crucial issue at all levels of abstractions in VLSI Design. Power estimation has to be performed repeatedly to explore the design space throughout the design process at all levels. Dynamic Power Dissipation due to Switching Activity has been one of the major concerns in Power Estimation. While many Simulation and Statistical Simulation based methods exist to estimate Switching Activity, these methods are input pattern sensitive, hence would require a large input vector set to accurately estimate Power. Probabilistic estimation of switching activity under Zero-Delay conditions, seriously undermines the accuracy of the estimation process, since it fails …

Behavioral Vhdl Implementation Of Coherent Digital Gps Signal Receiver, Viswanath Daita

USF Tampa Graduate Theses and Dissertations

Global Positioning System is a technology which is gaining acceptance. Originally developed for military purposes, it is being used in civilian applications such as navigation, emergency services, etc. A system-on-chip application merges different functions and applications on a single substrate. This project models a GPS receiver for a system on chip application. The GPS receiver, developed as a core, is intended to be a part of a navigation tour guide being developed. The scope of this work is the GPS C/A code on the L1 carrier. The digital signal processing back-end in a GPS receiver is modelled in this work. …

Behavioral And Rt-Level Estimation And Optimization Of Crosstalk In Vlsi Asics, Suvodeep Gupta

USF Tampa Graduate Theses and Dissertations

Downscaling of technology causes signal integrity problems due to crosstalk between closely-spaced interconnect lines. Existing crosstalk estimation and optimization techniques operate at the layout-level of circuits and fail to utilize the efficient design-space exploration at the high-level. To address this, we propose word-level statistical techniques which estimate crosstalk between bus lines: (1) Given a data stream, the first technique simply counts the number of crosstalk events on each bus line. The drawback of this technique is that the execution time is proportional to the stream length. This is overcome by the second enumerative technique which is purely statistical in nature. …

Development Of Assessment Tasks To Measure The Driving Capabilities Of Persons With Disabilities, Ashwin Upadhyay

USF Tampa Graduate Theses and Dissertations

The need to lead an independent and fuller life is as much a right of a person with physical disability as any other human being. Driving capabilities of a person with a disability have been assessed and evaluated using qualitative techniques. However, certain inadequacies that arise using qualitative measures can be avoided if the assessment is based on quantitative techniques.

The above requirement necessitates the need to devise a method and a system which is focused on the right development of the techniques used in assessing and measuring different capabilities (such as range of motion and force input) of the …

"Studying Up" In Tampa Bay: Globalization And Business Elites, Jennifer Laurel Avery

USF Tampa Graduate Theses and Dissertations

This thesis presents results of research I conducted during Spring 2003 through an internship with a private economic development organization (called here the TBEDO) that markets the strategically branded, seven-county region know as Tampa Bay domestically and internationally. This internship provided me with the means to conduct research about Tampa Bay's international economy and explore the elusive topic of globalization. It provided me with networking opportunities needed to "study up" on business elites and to understand what their international development agendas are, how they accomplish these objectives, whether they subscribe to the belief that the world has undergone a qualitative …

Creating A Distributed Field Robot Architecture For Multiple Robots, Matthew T. Long

USF Tampa Graduate Theses and Dissertations

This thesis describes the design and implementation of a distributed robot architecture, Distributed Field Robot Architecture. The approach taken in this thesis is threefold. First, the distributed architecture builds on existing hybrid deliberative/reactive architectures used for individual robots rather than creating a distributed architecture that requires re-engineering of existing robots. Second, the distributed layer of the architecture incorporates concepts from artificial intelligence and software agents. Third, the architecture is designed around Suns Jini middleware layer, rather than creating a middleware layer from scratch or attempting to adapt a software agent architecture. This thesis makes three primary contributions, both theoretical and …

Design And Testing Of A Prototype Gripper For A Wheelchair Mounted Robot, Koushik R. Barhale

USF Tampa Graduate Theses and Dissertations

The application of technology makes a lot of things easier, but for individuals with disability, it makes things possible. Rehabilitation robotics aims at providing robotic devices, which can act as functional extensions of the user, while performing basic activities. Providing a well-designed gripper as its end-effector can greatly enhance the performance of a rehabilitation robot. The gripper performs simple tasks like picking up objects and manipulating objects, which help in performing activities of daily living.

This thesis describes the development of a prototype gripper for a wheelchair mounted robot. The pre-development surveys conducted before the development of commercialized robotic assistive …

Adapting The Green And Ampt Model To Account For Air Compression And Counterflow, Darwiche Sabeh

USF Tampa Graduate Theses and Dissertations

One of the earliest functions to express infiltration as a function of time was introduced by Green and Ampt. In this study their formula was modified to account for air compression and counterflow. Physically,infiltration, air compression, and counterflow occur simultaneously, while in this model they are decoupled within a time step. Counterflow is calculated as a mass flux and pressure is found using the perfect gas law. First, a comparison of three infiltration methods, the original Green and Ampt formulation, a modified version incorporating air compression only, and the third version including air compression and counterflow, was conducted. Then sensitivity …

Application Of Support Vector Machines And Neural Networks In Digital Mammography: A Comparative Study, Nivedita V. Candade

USF Tampa Graduate Theses and Dissertations

Microcalcification (MC) detection is an important component of breast cancer diagnosis. However, visual analysis of mammograms is a difficult task for radiologists. Computer Aided Diagnosis (CAD) technology helps in identifying lesions and assists the radiologist in making his final decision.

This work is a part of a CAD project carried out at the Imaging Science Research Division (ISRD), Digital Medical Imaging Program, Moffitt Cancer Research Center, Tampa, FL. A CAD system had been previously developed to perform the following tasks: (a) pre-processing, (b) segmentation and (c) feature extraction of mammogram images. Ten features covering spatial, and morphological domains were extracted …

An Interdisciplinary Course For Non-Science Majors: Students' Views On Science Attitudes, Beliefs, And The Nature Of Science, Gary Eugene Brannan

USF Tampa Graduate Theses and Dissertations

This study's purpose was to investigate the differences in the attitudes towards science, belief in science, and the understanding of the nature of science between pre-service elementary education majors who took a two-semester interdisciplinary course called "Science That Matters" (ISC 1004 & ISC 1005) with those pre-service elementary education majors who took two undergraduate science courses other than the two-semester interdisciplinary science course.

The research method employed a 30-item survey (Moore & Foy, 1997) entitled Scientific Attitude Inventory II. The survey's participants were two classes who had taken both semesters of the interdisciplinary course (n = 23) compared with six …

Design And Testing Of A Marsupial/Companion Robot Prototype For A Powered Wheelchair, Sashi Kumar Konda

USF Tampa Graduate Theses and Dissertations

Individuals with disabilities yearn for an increased level of independence, seeking to supplement their missing function(s) and to carry on with their lives with minimal or no assistance from another person. A review of the existing assistive-care products has revealed that many of the defects in these devices, particularly in wheelchair-mounted robots, can be alleviated. Surveys have also identified tasks that users would like to perform by themselves, but are constrained from doing so by using currently available devices. An attempt has been made here to try to resolve these issues by developing a prototype of a marsupial robot that …

Vhdl Coding Style Guidelines And Synthesis: A Comparative Approach, Shahabuddin L. Inamdar

USF Tampa Graduate Theses and Dissertations

With the transistor density on an integrated circuit doubling every 18 months, Moore’s law seems likely to hold for another decade at least. This exponential growth in digital circuits has led to its increased complexity, better performance and is quickly getting less manageable for design engineers.

To combat this complexity, CAD tools have been introduced and are still being continuously developed, which prove to be of great help in the digital industry. One of the technologies, that is rapidly evolving as an industry standard, is the Very High Speed Integrated Circuit Hardware Description Language, (VHDL), language. The VHDL standard language …

Stimulus-Free Rt Level Power Model Using Belief Propagation, Sathishkumar Ponraj

USF Tampa Graduate Theses and Dissertations

Power consumption is one of the major bottlenecks in current and future VLSI design. Early microprocessors, which consumed a few tens of watts, are now replaced by millions of transistors and with the introduction of easy-to-design tools to explore at unbelievable minimum dimensions, increase in chip density is increasing at a alarming rate and necessitates faster power estimation methods. Gate level power estimation techniques are highly accurate methods but when time is the main constraint, power has to be estimated a lot higher in the abstraction level. Estimating power at higher levels also saves valuable time and cost involved in …

Modification Of Karst Depressions By Urbanization In Pinellas County, Florida, Kelly V. Wilson

USF Tampa Graduate Theses and Dissertations

This thesis analyzes some of the effects of urbanization in Pinellas County, Florida on the karst landscape. Many sinkholes have been obscured and/or modified for storm water retention by urbanization in Pinellas County, with a few sinkholes still identifiable by characteristic zoning of vegetation, soil moisture, and circular shape. Using aerial photos from 1926 and 2000, karst features were identified by circularity,vegetation, and moisture conditions. Mapping karst surface features using historic aerial photos and maps is a useful exercise that will assist our scientific understanding of karstification in Florida and the nature and extent of karst processes that have acted …

A Heuristic Methodology For Locating Monitoring Stations To Detect Contamination Events In Potable Water Distribution Systems, James R. Chastain Jr.

USF Tampa Graduate Theses and Dissertations

The requirements to protect public water systems from intentional contamination have expanded in the years following September 11, 2001. The areal extent and non-linear nature of water demand and movement in the distribution system makes efficient location of sampling points difficult. This difficulty is compounded by the fact that contamination conceptually can occur at any point and at any time within the distribution system. Small to mid-sized water systems are especially at a disadvantage in addressing this issue due to limited resources available to them.

This paper proposes a heuristic methodology to identify strategic locations within the system that can …

The Effects Of Varying Plating Variables On The Morphology Of Palladium Nanostructures For Hydrogen Sensing Applications, Ophir Ortiz

USF Tampa Graduate Theses and Dissertations

Present state-of-the-art hydrogen sensors are limited by a number of defects such as poisoning effects, slow response, and/or the range of concentrations that can be detected. Thus, hydrogen sensors are currently under investigation. In the search for the ultimate sensor, a variety of materials have been employed as the sensing layer. One of these materials is palladium. Palladium is widely used for hydrogen sensing due to its high selectivity and property of spontaneously absorbing hydrogen. Thin and thick film palladium hydrogen sensors have been reported, as well as palladium nanostructures. Specifically, palladium nanowires for hydrogen sensing have had improved results …

The Generation Of A Digital Phantom For Testing Of Digitally Reconstructed Radiographs, Nicholas Andrew, Mason

USF Tampa Graduate Theses and Dissertations

The construction of phantoms for testing imaging parameters has been well documented in the literature. As computers have been introduced into the different areas of medicine, they have become more and more relied upon to replace conventional technologies. One specific example is that of plane film X-rays. Digitally Reconstructed Radiographs (DRR's) are computer generated images that are generated from a 3 D volume of data, such as CT or MRI axial scans, and can be used in place of conventional X rays. The computer can generate a DRR image for any position, orientation and magnification, and geometries not physically possible …

A Complete Probabilistic Framework For Learning Input Models For Power And Crosstalk Estimation In Vlsi Circuits, Nirmal Munuswamy Ramalingam

USF Tampa Graduate Theses and Dissertations

Power disspiation is a growing concern in VLSI circuits. In this work we model the data dependence of power dissipation by learning an input model which we use for estimation of both switching activity and crosstalk for every node in the circuit. We use Bayesian networks to effectively model the spatio-temporal dependence in the inputs and we use the probabilistic graphical model to learn the structure of the dependency in the inputs. The learned structure is representative of the input model. Since we learn a causal model, we can use a larger number of independencies which guarantees a minimal structure. …

Deterioration Process And Deck Failure Mechanism Of Florida’S Precast Deck Panel Bridges, Ivan A. Gualtero

USF Tampa Graduate Theses and Dissertations

During the late 70's and early 80's, several precast deck panel bridges were constructed in Florida. These utilize prestressed precast panels as stay-in-place forms and are designed to act compositely with a cast-in-place deck which is poured subsequently. Such bridges offer advantages of quicker construction and lower costs. However, several such bridges built in Florida developed extensive cracking and spalling. Following localized failures, the Florida Department of Transportation has decided to replace all 127 precast panel deck bridges in Districts 1 and 7. Since deck replacement is contingent on funding, it is necessary to develop a rational procedure to decide …

Innovative Procedure To Install A Trunnion-Hub Assembly In A Bascule Bridge Girder, Michael West Berlin

USF Tampa Graduate Theses and Dissertations

The current assembly procedure to install a trunnion and hub into a bascule bridge girder involves cooling the trunnion in liquid nitrogen and shrink fitting it into the hub. The resulting trunnion-hub assembly is then allowed to warm to room temperature. Next, the trunnion-hub assembly is cooled in the liquid nitrogen and shrunk fit into the girder. The cooling of the trunnion does not cause any problems, however, when the trunnion-hub assembly is cooled in the liquid nitrogen, the hub experiences a large thermal shock. These thermal shocks induce large stresses into the hub, which has been known to cause …

Graphical Probabilistic Switching Model: Inference And Characterization For Power Dissipation In Vlsi Circuits, Shiva Shankar Ramani

USF Tampa Graduate Theses and Dissertations

Power dissipation in a VLSI circuit poses a serious challenge in present and future VLSI design. A switching model for the data dependent behavior of the transistors is essential to model dynamic, load-dependent active power and also leakage power in active mode - the two components of power in a VLSI circuit. A probabilistic Bayesian Network based switching model can explicitly model all spatio-temporal dependency relationships in a combinational circuit, resulting in zero-error estimates. However, the space-time requirements of exact estimation schemes, based on this model, increase with circuit complexity [5, 24]. This work explores a non-simulative, importance sampling based, …