Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 169

Full-Text Articles in Entire DC Network

Identifying Common Ultrasonic Predictive Failure Signatures In Bearing Elements For The Development Of An Automated Condition Based Ultrasonic Monitoring Controller., Jason Eric Johnson Dec 2005

Identifying Common Ultrasonic Predictive Failure Signatures In Bearing Elements For The Development Of An Automated Condition Based Ultrasonic Monitoring Controller., Jason Eric Johnson

Electronic Theses and Dissertations

This thesis presents a new method for Condition Based Ultrasonic Monitoring to be applied in conjunction with a lubrication distribution controller. As part of this thesis, algorithms were developed using ultrasonic sensors to control the application of lubrication to machinery. The controller sensors detect an ultrasonic signal from rolling or sliding machine elements. This signal then alerts the controller to dispense the proper amount of lubrication when needed, as opposed to a time schedule based on average performance or history. The work from this thesis will be used to help reduce equipment downtime and maintenance cost when utilized in an …


A Microreactor System For Measuring Size Selectivity In Porous Wo3 Sensor Materials, Meng Lu Dec 2005

A Microreactor System For Measuring Size Selectivity In Porous Wo3 Sensor Materials, Meng Lu

Electronic Theses and Dissertations

Our interest in studying reactions catalyzed by high surface area W03 powders is based on their potential application as the active material in sensors for low level (ppb) detection of flammable or toxic gases. A series of porous W03 powders with both meso- and micro-porosity have been synthesized by Waghe and Tripp. Preliminary results of the response of sensors fabricated from these materials indicated the possibility of size selectivity on the molecular scale. To provide support for the hypothesis of size selectivity and understand the reaction kinetics of alcohols over the new porous W03 powders for sensor …


Cost Effective Human Protein C Purification From Cohn Fraction Iv-1 Using Mini-Antibody., Doh Gyeuhn Ahn 1969- Aug 2005

Cost Effective Human Protein C Purification From Cohn Fraction Iv-1 Using Mini-Antibody., Doh Gyeuhn Ahn 1969-

Electronic Theses and Dissertations

Protein C (PC) is an important anticoagulant, antithrombotic, and antiinflammatory in blood plasma. PC deficiency can lead to severe venous thrombotic events, including lung embolism, stroke, and heart attack. In the body, PC is activated only when it is needed, and, therefore, PC does not cause bleeding problems that currently available anticoagulants may do. Purification of PC from plasma is currently done by immunoaffinity chromatography using monoclonal antibodies (Mabs), which is very expensive. Single chain variable regions (mini-Mab) with a PC binding capability, which can be produced in recombinant E. coli , were developed for PC purification. Compared to Mabs, …


Design And Development Of A Mems-Based Capacitive Bending Strain Sensor And A Biocompatible Housing For A Telemetric Strain Monitoring System., Julia Marie Weyer Aebersold 1969- May 2005

Design And Development Of A Mems-Based Capacitive Bending Strain Sensor And A Biocompatible Housing For A Telemetric Strain Monitoring System., Julia Marie Weyer Aebersold 1969-

Electronic Theses and Dissertations

Lumbar arthrodesis or spinal fusion is usually performed to relieve back pain and regain functionality from ruptured discs, disc degenerative disease, trauma and scoliosis. Metal rods are often fixed to the spine with screws or hooks, while fusion develops on the affected vertebrae. Fusion is determined by visual examination of radiographic images (X-ray), computed tomography (CT) scans or magnetic resonance imaging (MRI), yet these inspection procedures are subjective methods of review. They do not objectively confirm the presence of spinal fusion, which can lead to exploratory surgery to determine if fusion has occurred. Therefore, a need has arisen to develop …


Arc-Discharge In Solution: A Novel Synthesis Method For Carbon Nanotubes And In Situ Decoration Of Carbon Nanotubes With Nanoparticles, Debasis Bera Jan 2005

Arc-Discharge In Solution: A Novel Synthesis Method For Carbon Nanotubes And In Situ Decoration Of Carbon Nanotubes With Nanoparticles, Debasis Bera

Electronic Theses and Dissertations

Nanotechnology has reached the status of the 21st century's leading science and technology based on fundamental and applied research during the last two decades. An important feature of nanotechnology is to bridge the crucial dimensional gap between the atomic and molecular fundamental sciences and microstructural scale of engineering. Accordingly, it is very important to have an in-depth understanding of the synthesis of nanomaterials for the use of state-of-the-art high technological devices with enhanced properties. Recently, the 'bottom-up' approach for the fabrication of nanomaterials has received a great deal of attention for its simplicity and cost effectiveness. Tailoring the various parameters …


Sounding Rocket Redesign And Optimization For Payload Expansion And In Flight Telemetry Transmittal, Matthew Huffman Jan 2005

Sounding Rocket Redesign And Optimization For Payload Expansion And In Flight Telemetry Transmittal, Matthew Huffman

Electronic Theses and Dissertations

Due to renewed interest in the sub orbital rocket program of the Florida Space Authority and a surplus of Super Loki Sounding Rockets, an effort to improve the usefulness of this surplus is herein undertaken. Currently, the capacity of the payload compartment in the upper stage of the Super Loki system is very limited. A redesign of the upper stage will allow larger and more versatile payloads to be carried, assuming the appropriate design parameters are met. It has therefore been undertaken to create a design procedure that is comprehensive in scope in order to affect this redesign. This procedure …


Development Of A Motor Speed Control System Using Matlab And Simulink, Implemented With A Digital Signal Processor, Andrew Klee Jan 2005

Development Of A Motor Speed Control System Using Matlab And Simulink, Implemented With A Digital Signal Processor, Andrew Klee

Electronic Theses and Dissertations

This thesis describes an improved methodology for embedded software development. MATLAB and Simulink allow engineers to simplify algorithm development and avoid duplication of effort in deploying these algorithms to the end hardware. Special new hardware targeting capabilities of MATLAB and Simulink are described in detail. A motor control system design served to demonstrate the efficacy of this new method. Initial data was collected to help model the motor in Simulink. This allowed for the design of the open and closed loop control systems. The designed system was very effective, with good response and no steady state error. The entire design …


Effects Of Reduced Ras And Volume On Anaerobic Zone Performance For A Septic Wastewater Biological Phosphorous Removal System, Daniel Magro Jan 2005

Effects Of Reduced Ras And Volume On Anaerobic Zone Performance For A Septic Wastewater Biological Phosphorous Removal System, Daniel Magro

Electronic Theses and Dissertations

Enhanced Biological Phosphorous Removal (EBPR) performance was found to be adequate with reduced Return Activated Sludge (RAS) flows (50% of available RAS) to the anaerobic tank and smaller than typical anaerobic zone volume (1.08 hours hydraulic retention time or HRT). Three identical parallel biological nutrient removal (BNR) pilot plants were fed with strong, highly fermented (160 mg/L VFAs), domestic/industrial wastewater from a full scale wastewater treatment facility (WWTF). The pilot plants were operated at 100%, 50%, 40% and 25% RAS (percent of available RAS) flows to the anaerobic tank with the remaining RAS to the anoxic tank. In addition, varying …


Rollback-Able Random Number Generators For The Synchronous Parallel Environment For Emulation And Discrete-Event Simulation (Spe, Ramaswamy Karthik Narayanan Jan 2005

Rollback-Able Random Number Generators For The Synchronous Parallel Environment For Emulation And Discrete-Event Simulation (Spe, Ramaswamy Karthik Narayanan

Electronic Theses and Dissertations

Random Numbers form the heart and soul of a discrete-event simulation system. There are few situations where the actions of the entities in the process being simulated can be completely predicted in advance. The real world processes are more probabilistic than deterministic. Hence, such chances are represented in the system by using various statistical models, like random number generators. These random number generators can be used to represent a various number of factors, such as length of the queue. However, simulations have grown in size and are sometimes required to run on multiple machines, which share the various methods or …


Analysis And Simulation Tools For Solar Array Power Systems, Nattorn Pongratananukul Jan 2005

Analysis And Simulation Tools For Solar Array Power Systems, Nattorn Pongratananukul

Electronic Theses and Dissertations

This dissertation presents simulation tools developed specifically for the design of solar array power systems. Contributions are made in several aspects of the system design phases, including solar source modeling, system simulation, and controller verification. A tool to automate the study of solar array configurations using general purpose circuit simulators has been developed based on the modeling of individual solar cells. Hierarchical structure of solar cell elements, including semiconductor properties, allows simulation of electrical properties as well as the evaluation of the impact of environmental conditions. A second developed tool provides a co-simulation platform with the capability to verify the …


A Dynamic Model Of The Human/Cooling System/Clothing/Environment System, Zhengxiang Pu Jan 2005

A Dynamic Model Of The Human/Cooling System/Clothing/Environment System, Zhengxiang Pu

Electronic Theses and Dissertations

The human body compensates well for moderate climatic heat stress, but artificial environments often block or overwhelm physiological defense mechanism. Personal protective equipment (PPE) is one of sources of heat stress. It protects individual from chemical, physical, or biological hazards, but the high thermal insulation and low vapor permeability of PPE may also lead to substantial heat stress. Personal cooling is widely used to alleviate heat stress, especially for those situations where ambient environmental cooling is not economically viable or feasible. It is important to predict the physiological responses of a person wearing PPE with personal cooling to make sure …


Enhancing Message Privacy In Wired Equivalent Privacy., Darshan Purandare Jan 2005

Enhancing Message Privacy In Wired Equivalent Privacy., Darshan Purandare

Electronic Theses and Dissertations

The 802.11 standard defines the Wired Equivalent Privacy (WEP) and encapsulation of data frames. It is intended to provide data privacy to the level of a wired network. WEP suffered threat of attacks from hackers owing to certain security shortcomings in the WEP protocol. Lately, many new protocols like WiFi Protected Access (WPA), WPA2, Robust Secure Network (RSN) and 802.11i have come into being, yet their implementation is fairly limited. Despite its shortcomings one cannot undermine the importance of WEP as it still remains the most widely used system and we chose to address certain security issues and propose some …


Autonomous Repair Of Optical Character Recognition Data Through Simple Voting And Multi-Dimensional Indexing Techniques, Christopher Sprague Jan 2005

Autonomous Repair Of Optical Character Recognition Data Through Simple Voting And Multi-Dimensional Indexing Techniques, Christopher Sprague

Electronic Theses and Dissertations

The three major optical character recognition (OCR) engines (ExperVision, Scansoft OCR, and Abby OCR) in use today are all capable of recognizing text at near perfect percentages. The remaining errors however have proven very difficult to identify within a single engine. Recent research has shown that a comparison between the errors of the three engines proved to have very little correlation, and thus, when used in conjunction, may be useful to increase accuracy of the final result. This document discusses the implementation and results of a simple voting system designed to prove the hypothesis and show a statistical improvement in …


Famtile: An Algorithm For Learning High-Level Tactical Behavior From Observation, Brian Stensrud Jan 2005

Famtile: An Algorithm For Learning High-Level Tactical Behavior From Observation, Brian Stensrud

Electronic Theses and Dissertations

This research focuses on the learning of a class of behaviors defined as high-level behaviors. High-level behaviors are defined here as behaviors that can be executed using a sequence of identifiable behaviors. Represented by low-level contexts, these behaviors are known a priori to learning and can be modeled separately by a knowledge engineer. The learning task, which is achieved by observing an expert within simulation, then becomes the identification and representation of the low-level context sequence executed by the expert. To learn this sequence, this research proposes FAMTILE - the Fuzzy ARTMAP / Template-Based Interpretation Learning Engine. This algorithm attempts …


Compressed Pattern Matching For Text And Images, Tao Tao Jan 2005

Compressed Pattern Matching For Text And Images, Tao Tao

Electronic Theses and Dissertations

The amount of information that we are dealing with today is being generated at an ever-increasing rate. On one hand, data compression is needed to efficiently store, organize the data and transport the data over the limited-bandwidth network. On the other hand, efficient information retrieval is needed to speedily find the relevant information from this huge mass of data using available resources. The compressed pattern matching problem can be stated as: given the compressed format of a text or an image and a pattern string or a pattern image, report the occurrence(s) of the pattern in the text or image …


Solar-Based Single-Stage High-Efficiency Grid-Connected Inverter, Feng Tian Jan 2005

Solar-Based Single-Stage High-Efficiency Grid-Connected Inverter, Feng Tian

Electronic Theses and Dissertations

Renewable energy source plays an important role in the energy cogeneration and distribution. Traditional solar-based inverter system is two stages in cascaded, which has a simpler controller but low efficiency. A new solar-based single-stage grid-connected inverter system can achieve higher efficiency by reducing the power semiconductor switching loss and output stable and synchronized sinusoid current into the utility grid. Controlled by the digital signal processor, the inverter can also draw maximum power from the solar array, thereby maximizing the utilization of the solar array. In Chapter 1, a comparison between the traditional two-stage inverter and the single-stage inverter is made. …


Transmission Electron Microscopy Studies In Shape Memory Alloys, Madhavi Tiyyagura Jan 2005

Transmission Electron Microscopy Studies In Shape Memory Alloys, Madhavi Tiyyagura

Electronic Theses and Dissertations

In NiTi, a reversible thermoelastic martensitic transformation can be induced by temperature or stress between a cubic (B2) austenite phase and a monoclinic (B19') martensite phase. Ni-rich binary compositions are cubic at room temperature (requiring stress or cooling to transform to the monoclinic phase), while Ti-rich binary compositions are monoclinic at room temperature (requiring heating to transform to the cubic phase). The stress induced transformation results in the superelastic effect, while the thermally induced transformation is associated with strain recovery that results in the shape memory effect. Ternary elemental additions such as Fe can additionally introduce an intermediate rhombohedral (R) …


Developing An Object-Oriented Approach For Operations Simulation In Speedes, Amit Wasadikar Jan 2005

Developing An Object-Oriented Approach For Operations Simulation In Speedes, Amit Wasadikar

Electronic Theses and Dissertations

Using simulation techniques, performance of any proposed system can be tested for different scenarios with a generated model. However, it is difficult to rapidly create simulation models that will accurately represent the complexity of the system. In recent years, Object-Oriented Discrete-Event Simulation has emerged as the potential technology to implement rapid simulation schemes. A number of software based on programming languages like C++ and Java are available for carrying out Object Oriented Discrete-Event Simulation. These software packages establish a general framework for simulation in computer programs, but need to be further customized for desired end-use applications. In this thesis, a …


Safety Issues Of Red-Light Running And Unprotected Left-Turn At Signalized Intersections, Xuedong Yan Jan 2005

Safety Issues Of Red-Light Running And Unprotected Left-Turn At Signalized Intersections, Xuedong Yan

Electronic Theses and Dissertations

Crashes categorized as running red light or left turning are most likely to occur at signalized intersections and resulted in substantial severe injuries and property damages. This dissertation mainly focused on these two types of vehicle crashes and the research methodology involved several perspectives. To examine the overall characteristics of red-light running and left-turning crashes, firstly, this study applied 1999-2001 Florida traffic crash data to investigate the accident propensity of three aspects of risk factors related to traffic environments, driver characteristics, and vehicle types. A quasi-induced exposure concept and statistical techniques including classification tree model and multiple logistic regression were …


Transform Based And Search Aware Text Compression Schemes And Compressed Domain Text Retrieval, Nan Zhang Jan 2005

Transform Based And Search Aware Text Compression Schemes And Compressed Domain Text Retrieval, Nan Zhang

Electronic Theses and Dissertations

In recent times, we have witnessed an unprecedented growth of textual information via the Internet, digital libraries and archival text in many applications. While a good fraction of this information is of transient interest, useful information of archival value will continue to accumulate. We need ways to manage, organize and transport this data from one point to the other on data communications links with limited bandwidth. We must also have means to speedily find the information we need from this huge mass of data. Sometimes, a single site may also contain large collections of data such as a library database, …


Optimization Of An Unstructured Finite Element Mesh For Tide And Storm Surge Modeling Applications In The Western North Atlantic Ocean, Satoshi Kojima Jan 2005

Optimization Of An Unstructured Finite Element Mesh For Tide And Storm Surge Modeling Applications In The Western North Atlantic Ocean, Satoshi Kojima

Electronic Theses and Dissertations

Recently, a highly resolved, finite element mesh was developed for the purpose of performing hydrodynamic calculations in the Western North Atlantic Tidal (WNAT) model domain. The WNAT model domain consists of the Gulf of Mexico, the Caribbean Sea, and the entire portion of the North Atlantic Ocean found west of the 60° W meridian. This high resolution mesh (333K) employs 332,582 computational nodes and 647,018 triangular elements to provide approximately 1.0 to 25 km node spacing. In the previous work, the 333K mesh was applied in a Localized Truncation Error Analysis (LTEA) to produce nodal density requirements for the WNAT …


A Comparative Analysis Between Context-Based Reasoning (Cxbr) And Contextual Graphs (Cxgs)., Peterson Marthen Lorins Jan 2005

A Comparative Analysis Between Context-Based Reasoning (Cxbr) And Contextual Graphs (Cxgs)., Peterson Marthen Lorins

Electronic Theses and Dissertations

Context-based Reasoning (CxBR) and Contextual Graphs (CxGs) involve the modeling of human behavior in autonomous and decision-support situations in which optimal human decision-making is of utmost importance. Both formalisms use the notion of contexts to allow the implementation of intelligent agents equipped with a context sensitive knowledge base. However, CxBR uses a set of discrete contexts, implying that models created using CxBR operate within one context at a given time interval. CxGs use a continuous context-based representation for a given problem-solving scenario for decision-support processes. Both formalisms use contexts dynamically by continuously changing between necessary contexts as needed in appropriate …


Graph-Theoretic Approach To Modeling Propagation And Control Of Network Worms, Zoran Nikoloski Jan 2005

Graph-Theoretic Approach To Modeling Propagation And Control Of Network Worms, Zoran Nikoloski

Electronic Theses and Dissertations

In today's network-dependent society, cyber attacks with network worms have become the predominant threat to confidentiality, integrity, and availability of network computing resources. Despite ongoing research efforts, there is still no comprehensive network-security solution aimed at controling large-scale worm propagation. The aim of this work is fivefold: (1) Developing an accurate combinatorial model of worm propagation that can facilitate the analysis of worm control strategies, (2) Building an accurate epidemiological model for the propagation of a worm employing local strategies, (3) Devising distributed architecture and algorithms for detection of worm scanning activities, (4) Designing effective control strategies against the worm, …


Three Dimensional Modeling Of Wekiva Springshed With Wash123d, Sandeep Paladagu Jan 2005

Three Dimensional Modeling Of Wekiva Springshed With Wash123d, Sandeep Paladagu

Electronic Theses and Dissertations

This thesis presents a three-dimensional groundwater modeling of Wekia springshed in central Florida using a numerical model, WASH123D. Springs have historically played an important role in Florida's history. The Wekiva River is a spring-fed system associated with about 19 springs connected to the Floridan aquifer. With increased urbanization and population growth in this region, there has been an increased strain on the water levels of Floridan aquifer which is a major source of potable water. Maintaining groundwater recharge to the aquifer is a key factor of the viability of the regional water supply as well as Wekiva ecosystem. Hence, the …


Finite Element Evaluation Of The Effects Of Lateral Anchorage Strips On The Behavior Of Cfrp-Strengthened Rc Beams, Jose Javier Perez Jan 2005

Finite Element Evaluation Of The Effects Of Lateral Anchorage Strips On The Behavior Of Cfrp-Strengthened Rc Beams, Jose Javier Perez

Electronic Theses and Dissertations

In this thesis, a fully nonlinear finite element study of the flexural behavior of doubly reinforced concrete beams strengthened using different Carbon Fiber Reinforced Polymer (CFRP) composite strengthening configurations has been carried out. Prior to the study, a total of six beams were constructed, pre-cracked, strengthened and tested to failure under a four-point loading condition (Zhao and O'Riordan-Adjah, 2004). Then, for the purpose of this thesis work, detailed three dimensional finite element models were created not only to correlate the results obtained from the experiments, but also to predict the load capacity, failure modes and crack pattern of reinforced concrete …


Interdiffusion Analysis For Nicocraly And Nial Vs. Various Superalloys, Emmanuel Perez Jan 2005

Interdiffusion Analysis For Nicocraly And Nial Vs. Various Superalloys, Emmanuel Perez

Electronic Theses and Dissertations

Hot section components in gas turbines can be NiCoCrAlY-coated to provide the component with an Al reservoir that maintains a protective oxide layer on its surface. Over the service life of the component, the coatings degrade by composition and phase changes due to oxidation/hot-corrosion, and multicomponent interdiffusion from and into the superalloy substrate. In this study, the rate of Al interdiffusion into selected Ni-base superalloys using various diffusion couples of two-phase NiCoCrAlY (beta + gamma) and single beta-phase NiAl with the selected alloys is measured. The diffusion couples were examined with an emphasis on the composition-dependence of Al interdiffusion. Microstructural …


Instrumented Nanoindentation Studies Of Deformation In Shape Memory Alloys, Sudhir Rajagopalan Jan 2005

Instrumented Nanoindentation Studies Of Deformation In Shape Memory Alloys, Sudhir Rajagopalan

Electronic Theses and Dissertations

Near equi-atomic nickel titanium (NiTi) shape memory alloys (SMAs) are a class of materials characterized by their unique deformation behavior. In these alloys, deformation mechanisms such as mechanical twinning and stress induced phase transformation between a high symmetry phase (austenite) and a low symmetry phase (martensite) additionally occur and influence mechanical behavior and thus their functionality. Consequently, applications of SMAs usually call for precise phase transformation temperatures, which depend on the thermomechanical history and the composition of the alloy. Instrumented indentation, inherently a mechanical characterization technique for small sampling volumes, offers a cost effective means of empirically testing SMAs in …


Investigation Of High-K Gate Dielectrics And Metals For Mosfet Devices., Sriram Mannargudi Seshadri Jan 2005

Investigation Of High-K Gate Dielectrics And Metals For Mosfet Devices., Sriram Mannargudi Seshadri

Electronic Theses and Dissertations

Progress in advanced microlithography and deposition techniques have made feasible high- k dielectric materials for MOS transistors. The continued scaling of CMOS devices is pushing the Si-SiO2 to its limit to consider high-k gate dielectrics. The demand for faster, low power, smaller, less expensive devices with good functionality and higher performance increases the demand for high-k dielectric based MOS devices. This thesis gives an in-depth study of threshold voltages of PMOS and NMOS transistors using various high-k dielectric materials like Tantalum pent oxide (Ta2O5), Hafnium oxide (HfO2), Zirconium oxide (ZrO2) and Aluminum oxide (Al2O3) gate oxides. Higher dielectric constant may …


Unified Large And Small Signal Discrete-Space Modeling For Pwm Converters In Ccm, Ehab Hamed Shoubaki Jan 2005

Unified Large And Small Signal Discrete-Space Modeling For Pwm Converters In Ccm, Ehab Hamed Shoubaki

Electronic Theses and Dissertations

In this Thesis a Unified Discrete State-Space Model for power converters in CCM is presented. Two main approaches to arriving at the discrete model are used. The first approach involves an impulse function approximation of the duty cycle modulations of the converter switches , and this approach results in a small signal discrete model. The Second approach is direct and does not involve any approximation of the modulations , this approach yields both a large signal nonlinear discrete model and a linear small signal model. Harmonic analysis of the converter states at steady-state is done for steady-state waveform acquisition , …


Oceanic Rain Identification Using Multifractal Analysis Of Quikscat Sigma-0, Vasud Ganesh Torsekar Jan 2005

Oceanic Rain Identification Using Multifractal Analysis Of Quikscat Sigma-0, Vasud Ganesh Torsekar

Electronic Theses and Dissertations

The presence of rain over oceans interferes with the measurement of sea surface wind speed and direction from the Sea Winds scatterometer and as a result wind measurements contain biases in rain regions. In past research at the Central Florida Remote Sensing Lab, it has been observed that rain has multi-fractal behavior. In this report we present an algorithm to detect the presence of rain so that rain regions are flagged. The forward and aft views of the horizontal polarization σ0 are used for the extraction of textural information with the help of multi-fractals. A single negated multi-fractal exponent is …