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Articles 1 - 30 of 129
Full-Text Articles in Engineering
Design Of An Adaptive Autopilot For An Expendable Launch Vehicle, Clinton Plaisted
Design Of An Adaptive Autopilot For An Expendable Launch Vehicle, Clinton Plaisted
Electronic Theses and Dissertations
This study investigates the use of a Model Reference Adaptive Control (MRAC) direct approach to solve the attitude control problem of an Expendable Launch Vehicle (ELV) during its boost phase of flight. The adaptive autopilot design is based on Lyapunov Stability Theory and provides a useful means for controlling the ELV in the presence of environmental and dynamical uncertainties. Several different basis functions are employed to approximate the nonlinear parametric uncertainties in the system dynamics. The control system is designed so that the desire dresponse to a reference model would be tracked by the closed-loop system. The reference model is …
Severity Analysis Of Driver Crash Involvements On Multilane High Speed Arterial Corridors, Alexis Nevarez-Pagan
Severity Analysis Of Driver Crash Involvements On Multilane High Speed Arterial Corridors, Alexis Nevarez-Pagan
Electronic Theses and Dissertations
Arterial roads constitute the majority of the centerline miles of the Florida State Highway System. Severe injury involvements on these roads account for a quarter of the total severe injuries reported statewide. This research focuses on driver injury severity analysis of statewide multilane high speed arterials using crash data for the years 2002 to 2004. The first goal is to test different ways of analyzing crash data (by road entity and crash types) and find the best method of driver injury severity analysis. A second goal is to find driver, vehicle, road and environment related factors that contribute to severe …
Evaluation Of Climatic And Ecohydrological Effects On Longwave Radiation And Evapotranspiration, Maria Rizou
Evaluation Of Climatic And Ecohydrological Effects On Longwave Radiation And Evapotranspiration, Maria Rizou
Electronic Theses and Dissertations
Modern tools, nontraditional datasets and a better understanding of the interaction between climate and ecohydrology are continuously being developed as today's society is in critical need for improving water management, predicting hydrometeorological hazards and forecasting future climate. In particular, the study of the intra- and inter-annual variations in grass productivity and evapotranspiration caused by variations in precipitation/soil moisture and other biophysical factors is of great significance due to their relation to future climatic changes. The research presented here falls in three parts. In the first part of the dissertation, a land use adaptable model, based on the superposition of the …
A Reinforcement Learning Technique For Enhancing Human Behavior Models In A Context-Based Architecture, David Aihe
A Reinforcement Learning Technique For Enhancing Human Behavior Models In A Context-Based Architecture, David Aihe
Electronic Theses and Dissertations
A reinforcement-learning technique for enhancing human behavior models in a context-based learning architecture is presented. Prior to the introduction of this technique, human models built and developed in a Context-Based reasoning framework lacked learning capabilities. As such, their performance and quality of behavior was always limited by what the subject matter expert whose knowledge is modeled was able to articulate or demonstrate. Results from experiments performed show that subject matter experts are prone to making errors and at times they lack information on situations that are inherently necessary for the human models to behave appropriately and optimally in those situations. …
Taming Crowded Visual Scenes, Saad Ali
Taming Crowded Visual Scenes, Saad Ali
Electronic Theses and Dissertations
Computer vision algorithms have played a pivotal role in commercial video surveillance systems for a number of years. However, a common weakness among these systems is their inability to handle crowded scenes. In this thesis, we have developed algorithms that overcome some of the challenges encountered in videos of crowded environments such as sporting events, religious festivals, parades, concerts, train stations, airports, and malls. We adopt a top-down approach by first performing a global-level analysis that locates dynamically distinct crowd regions within the video. This knowledge is then employed in the detection of abnormal behaviors and tracking of individual targets …
Alayzing The Effects Of Modularity On Search Spaces, Ozlem Garibay
Alayzing The Effects Of Modularity On Search Spaces, Ozlem Garibay
Electronic Theses and Dissertations
We are continuously challenged by ever increasing problem complexity and the need to develop algorithms that can solve complex problems and solve them within a reasonable amount of time. Modularity is thought to reduce problem complexity by decomposing large problems into smaller and less complex subproblems. In practice, introducing modularity into evolutionary algorithm representations appears to improve search performance; however, how and why modularity improves performance is not well understood. In this thesis, we seek to better understand the effects of modularity on search. In particular, what are the effects of module creation on the search space structure and how …
A Multi-Objective No-Regret Decision Making Model With Bayesian Learning For Autonomous Unmanned Systems, Matthew Howard
A Multi-Objective No-Regret Decision Making Model With Bayesian Learning For Autonomous Unmanned Systems, Matthew Howard
Electronic Theses and Dissertations
The development of a multi-objective decision making and learning model for the use in unmanned systems is the focus of this project. Starting with traditional game theory and psychological learning theories developed in the past, a new model for machine learning is developed. This model incorporates a no-regret decision making model with a Bayesian learning process which has the ability to adapt to errors found in preconceived costs associated with each objective. This learning ability is what sets this model apart from many others. By creating a model based on previously developed human learning models, hundreds of years of experience …
Reducing Eddy Currents In High Magnetic Field Environments, Russell Case
Reducing Eddy Currents In High Magnetic Field Environments, Russell Case
Electronic Theses and Dissertations
When an electrical conducting volume is placed into the bore of an MRI undergoing an image scan, time varying magnetic gradients induce eddy currents in this conducting material. These eddy currents in turn produce a mechanical torque on this volume. It is the goal of this thesis to produce a computer simulation of eddy currents produced by placing conducting materials inside an MRI bore. The first part of the thesis establishes the physics and principles behind an MRI system along with several applications. Next, this thesis presents an analysis of eddy current effects produced on a conductor placed into an …
Bi-Directional Dcm Dc-To-Dc Converter For Hybrid Electric Vehicles, Michael Pepper
Bi-Directional Dcm Dc-To-Dc Converter For Hybrid Electric Vehicles, Michael Pepper
Electronic Theses and Dissertations
With the recent revival of the hybrid vehicle much advancement in power management has been made. The most popular hybrid vehicle, the hybrid electric vehicle, has many topologies developed to realize this hybrid vehicle. From these topologies, as sub set was created to define a particular group of vehicles where the converter discussed in this thesis has the most advantage. This sub set is defined by two electric sources of power coupled together at a common bus. This set up presents many unique operating conditions which can be handled seamlessly by the DC-to-DC converter when designed properly. The DC-to-DC converter …
Design, Characterization And Compact Modeling Of Novel Silicon Controlled Rectifier (Scr)-Based Devices For Electrostatic Discha, Lifang Lou
Electronic Theses and Dissertations
Electrostatic Discharge (ESD), an event of a sudden transfer of electrons between two bodies at different potentials, happens commonly throughout nature. When such even occurs on integrated circuits (ICs), ICs will be damaged and failures result. As the evolution of semiconductor technologies, increasing usage of automated equipments and the emerging of more and more complex circuit applications, ICs are more sensitive to ESD strikes. Main ESD events occurring in semiconductor industry have been standardized as human body model (HBM), machine model (MM), charged device model (CDM) and international electrotechnical commission model (IEC) for control, monitor and test. In additional to …
Transient Response Improvement For Multi-Phase Voltage Regulators, Shangyang Xiao
Transient Response Improvement For Multi-Phase Voltage Regulators, Shangyang Xiao
Electronic Theses and Dissertations
Next generation microprocessor (Vcore) requirements for high current slew rates and fast transient response together with low output voltage have posed great challenges on voltage regulator (VR) design . Since the debut of Intel 80X86 series, CPUs have greatly improved in performance with a dramatic increase on power consumption. According to the latest Intel VR11 design guidelines , the operational current may ramp up to 140A with typical voltages in the 1.1V to 1.4V range, while the slew rate of the transient current can be as high as 1.9A/ns [1, 2]. Meanwhile, the transient-response requirements are becoming stringer and stringer. …
Design Of Polynomial-Based Filters For Continuously Variable Sample Rate Conversion With Applications In Synthetic Instrumentati, Matthew Hunter
Design Of Polynomial-Based Filters For Continuously Variable Sample Rate Conversion With Applications In Synthetic Instrumentati, Matthew Hunter
Electronic Theses and Dissertations
In this work, the design and application of Polynomial-Based Filters (PBF) for continuously variable Sample Rate Conversion (SRC) is studied. The major contributions of this work are summarized as follows. First, an explicit formula for the Fourier Transform of both a symmetrical and nonsymmetrical PBF impulse response with variable basis function coefficients is derived. In the literature only one explicit formula is given, and that for a symmetrical even length filter with fixed basis function coefficients. The frequency domain optimization of PBFs via linear programming has been proposed in the literature, however, the algorithm was not detailed nor were explicit …
The Effects Of Phosphate And Silicate Inhibitors On Surface Roughness And Copper Release In Water Distribution Systems, David Macnevin
The Effects Of Phosphate And Silicate Inhibitors On Surface Roughness And Copper Release In Water Distribution Systems, David Macnevin
Electronic Theses and Dissertations
The effects of corrosion inhibitors on water quality and the distribution system were studied. This dissertation investigates the effect of inhibitors on iron surface roughness, copper surface roughness, and copper release. Corrosion inhibitors included blended poly/ortho phosphate, sodium orthophosphate, zinc orthophosphate, and sodium silicate. These inhibitors were added to a blend of surface water, groundwater, and desalinated brackish water. Surface roughness of galvanized iron, unlined cast iron, lined cast iron, and polyvinyl chloride was measured using pipe coupons exposed for three months. Roughness of each pipe coupon was measured with an optical surface profiler before and after exposure to inhibitors. …
A Comparative Analysis Of Green Roof Designs Including Depth Of Media, Drainage Layer Materials, And Pollution Control Media, Matt Kelly
Electronic Theses and Dissertations
Population growth has lead to an increase in development and impervious areas in urban settings. Post-development conditions cause several problems for stormwater management such as limited space for stormwater storage systems and the conveyance of pollution picked up by runoff to near by water bodies. Green Roofs with cisterns have been shown to attenuate the peak flow of storm events and reduce the pollution load leaving a site and entering nearby water bodies. The purpose of this research is to expand the available research data on green roofs with cisterns by investigating the water quality and hydrology effects of different …
Nutrient Removal From Stormwater By Using Green Sorption Media, Fahim Hossain
Nutrient Removal From Stormwater By Using Green Sorption Media, Fahim Hossain
Electronic Theses and Dissertations
High nitrogen and phosphorus content in storm water runoff has affected groundwater, springs and surface water by impacting ecosystem integrity and human health. Nitrate may be toxic and can cause human health problem such as methemoglobinemia, liver damage and even cancers. Phosphorus may trigger the eutrophication issues in fresh water bodies, which could result in toxic algae and eventually endanger the source of drinking waters. Sorption media with mixes of some recycled materials, such as sawdust and tire crumb, combined with sand/silt and limestone, becomes appealing for nutrient removal in environmental management. This paper presented is a specific type of …
Performance Based Decision System In Determining Post Closure Care (Pcc) Duration In Florida Landfills, Asawari Kulkarni
Performance Based Decision System In Determining Post Closure Care (Pcc) Duration In Florida Landfills, Asawari Kulkarni
Electronic Theses and Dissertations
This study is an evaluation of Post Closure Care (PCC) duration of landfills using performance based methodology. The post closure care phase begins once the landfill is closed. As required by the Resource Conservation Recovery Act (RCRA) Subtitle D, PCC duration for municipal solid waste landfills is 30 years. During the PCC period, the landfill operator/owner is required to conduct monitoring for leachate, landfill gas, and ground-water and maintain the integrity of the cap so that the landfill does not impose a threat to surrounding human health and environment (HH&E). The duration of PCC can be reduced by the director …
Comparison Of The Effectiveness Of Alternative Ferrate (Vi) Synthesis Formulas As Disinfectants For Wastewater And River Water, Rachelle Ginart
Comparison Of The Effectiveness Of Alternative Ferrate (Vi) Synthesis Formulas As Disinfectants For Wastewater And River Water, Rachelle Ginart
Electronic Theses and Dissertations
Ferrate (VI) has been studied as an alternative chemical to disinfect water and wastewater in recent years. The disinfection effectiveness of two different wet oxidation ferrate (VI) synthesis formulas in wastewater and Econlockhatchee River water was evaluated. Ferrate (VI) is synthesized by addition of ferric chloride to a mixture of sodium hydroxide and calcium hypochlorite (refer to U.S. Patent 6,790,429). One ferrate (VI) synthesis formula uses below the stoichiometric requirement of hypochlorite (Low Chlorine Formula) while the other ferrate (VI) synthesis formula uses more than the stoichiometric requirement of hypochlorite (Standard Chlorine Formula). For applications requiring low chlorine residual effluent …
Removal Of 2, 4-Dinitrophenol By Ferrate, Gianna Cooley
Removal Of 2, 4-Dinitrophenol By Ferrate, Gianna Cooley
Electronic Theses and Dissertations
Ferrate (molecular formula, FeVIO42-) has been studied increasingly since the 1970s as a disinfectant and coagulant for domestic wastewater and also as an oxidant for industrial wastewaters (Murmann and Roginson, 1974, Gilbert et al., 1978, Kazama, 1994, Jiang et al., 2002, and Sharmaet al., 2005). This research was performed to explore whether ferrate could possibly be used as chemical treatment for industrial wastewaters from plastic, chemical, dye, soap, and wood stain producing plants that contain 2, 4-Dinitrophenol (DNP). DNP is listed on the United States Environmental Protection Agency (EPA) Drinking Water Contaminant Candidate List (CCL). This list includes compounds which …
Evaluating The Performance Of Animal Shelters: An Application Of Data Envelopment Analysis, Brandy Heyde
Evaluating The Performance Of Animal Shelters: An Application Of Data Envelopment Analysis, Brandy Heyde
Electronic Theses and Dissertations
The focus of this thesis is the application of data envelopment analysis to understand and evaluate the performance of diverse animal welfare organizations across the United States. The results include identification of the most efficient animal welfare organizations, at least among those that post statistics on their operations, and a discussion of various partnerships that may improve the performance of the more inefficient organizations. The Humane Society of the United States estimates that there are 4000 - 6000 independently-run animal shelters across the United States, with an estimated 6-8 million companion animals entering them each year. Unfortunately, more than half …
Improving Airline Schedule Reliability Using A Strategic Multi-Objective Runway Slot Assignment Search Heuristic, Florian Hafner
Improving Airline Schedule Reliability Using A Strategic Multi-Objective Runway Slot Assignment Search Heuristic, Florian Hafner
Electronic Theses and Dissertations
Improving the predictability of airline schedules in the National Airspace System (NAS) has been a constant endeavor, particularly as system delays grow with ever-increasing demand. Airline schedules need to be resistant to perturbations in the system including Ground Delay Programs (GDPs) and inclement weather. The strategic search heuristic proposed in this dissertation significantly improves airline schedule reliability by assigning airport departure and arrival slots to each flight in the schedule across a network of airports. This is performed using a multi-objective optimization approach that is primarily based on historical flight and taxi times but also includes certain airline, airport, and …
The Creation Of Tools And Models To Characterize And Quantify User-Centered Design Considerations In Product And System Developm, Katherine Meza
The Creation Of Tools And Models To Characterize And Quantify User-Centered Design Considerations In Product And System Developm, Katherine Meza
Electronic Theses and Dissertations
Ease of use differentiates products in a highly competitive market place. It also brings an added value that culminates in a higher degree of customer satisfaction, repeated business, increased sales, and higher revenue. User-centered design is a strategic asset that companies can use to improve their customer relationships by learning more about their customers, and increase their sales. In today's economy, the measurement of intangible assets such as user experience has become a major need for industries because of the relationship between user-centered design and organizational benefits such as customer loyalty. As companies realize that the inclusion of user-centered design …
A Surrogate Measure Of Customer Satisfaction In The Manufacture Of Printed Wiring Boards, Adam Y. Maamoun
A Surrogate Measure Of Customer Satisfaction In The Manufacture Of Printed Wiring Boards, Adam Y. Maamoun
Electronic Theses and Dissertations
The objective of this research is to determine and develop a model that is capable of accurately measuring customer satisfaction for different industries and in particularly for the Printed Wiring Boards (PWB) Manufacturers. The new model will incorporate data not being collected or utilized by the survey method of determining customer satisfaction. The method used is a weighted average of satisfaction among several researched categories with percentages that accurately represent the relative importance of multiple facets of the PWB manufacturers customer satisfaction. A very common term in quality assurance is that "What is not measured accurately can not be evaluated …
Optimizing The Level Of Customization For Products In Mass Customization Systems, Sami Spahi
Optimizing The Level Of Customization For Products In Mass Customization Systems, Sami Spahi
Electronic Theses and Dissertations
Mass customization (MC) was developed to capitalize on the combined benefits of economies of scale and economies of scope. Balancing the tradeoffs involved in an MC system warrants the determination of the degree or the extent of customization. Most of the literature views the degree of customization as how early or how far the customer is integrated in the production cycle, which is defined as the order decoupling point. In this study we are addressing the degree of customization from a product structural perspective. There are two objectives in this research. The first is to develop a unit of measurement …
A Hybrid System Dynamics-Discrete Event Simulationapproach To Simulating The Manufacturing Enterprise, Magdy Helal
A Hybrid System Dynamics-Discrete Event Simulationapproach To Simulating The Manufacturing Enterprise, Magdy Helal
Electronic Theses and Dissertations
With the advances in the information and computing technologies, the ways the manufacturing enterprise systems are being managed are changing. More integration and adoption of the system perspective push further towards a more flattened enterprise. This, in addition to the varying levels of aggregation and details and the presence of the continuous and discrete types of behavior, created serious challenges for the use of the existing simulation tools for simulating the modern manufacturing enterprise system. The commonly used discrete event simulation (DES) techniques face difficulties in modeling such integrated systems due to increased model complexity, the lack of data at …
Improving Business Performance Through The Integration Of Human Factors Engineering Into Organizations Using A Systems Engineeri, Monica Philippart
Improving Business Performance Through The Integration Of Human Factors Engineering Into Organizations Using A Systems Engineeri, Monica Philippart
Electronic Theses and Dissertations
Most organizations today understand the valuable contribution employees as people (rather than simply bodies) provide to their overall performance. Although efforts are made to make the most of the human in organizations, there is still much room for improvement. Focus in the reduction of employee injuries such as cumulative trauma disorders rose in the 80 s. Attempts at increasing performance by addressing employee satisfaction through various methods have also been ongoing for several years now. Knowledge Management is one of the most recent attempts at controlling and making the best use of employees knowledge. All of these efforts and more …
Quantitative Thickness Mapping In High-Angle Annular Dark-Field (Haadf) Scanning Transmission Electron Microscopy (Stem), Haritha Nukala
Quantitative Thickness Mapping In High-Angle Annular Dark-Field (Haadf) Scanning Transmission Electron Microscopy (Stem), Haritha Nukala
Electronic Theses and Dissertations
Only a few methods are currently available for the measurement of sample thicknesses in Transmission Electron Microscopy (TEM). These methods, Convergent-Beam Electron Diffraction (CBED) and thickness mapping in Energy-Filtered TEM (EFTEM), are either elaborate or complex. In this present work, I have investigated and come up with a simple straight-forward method to measure the local thickness of a TEM sample with the atomic number (Z-contrast) imaging using High-Angle Annular Dark Field (HAADF) Scanning Transmission Electron Microscopy (STEM). HAADF STEM shows atomic number contrast for high scattering angles of the electrons, owing to predominant electron scattering at the potential of the …
Probing And Tuning The Size, Morphology, Chemistry And Structure Of Nanoscale Cerium Oxide, Satyanarayana Kuchibhatla
Probing And Tuning The Size, Morphology, Chemistry And Structure Of Nanoscale Cerium Oxide, Satyanarayana Kuchibhatla
Electronic Theses and Dissertations
Cerium oxide (ceria)-based materials in the nanoscale regime are of significant fundamental and technological interest. Nanoceria in pure and doped forms has current and potential use in solid oxide fuel cells, catalysis, UV- screening, chemical mechanical planarization, oxygen sensors, and bio-medical applications. The characteristic feature of Ce to switch between the +3 and + 4 oxidation states renders oxygen buffering capability to ceria. The ease of this transformation was expected to be enhanced in the nanoceria. In most the practical scenarios, it is necessary to have a stable suspension of ceria nanoparticles (CNPs) over longer periods of time. However, the …
Amorphous Phase Formation In Mechanically Alloyed Fe-Based Systems., Satyajeet Sharma
Amorphous Phase Formation In Mechanically Alloyed Fe-Based Systems., Satyajeet Sharma
Electronic Theses and Dissertations
Bulk metallic glasses have interesting combination of physical, chemical, mechanical, and magnetic properties which make them attractive for a variety of applications. Consequently there has been a lot of interest in understanding the structure and properties of these materials. More varied applications can be sought if one understands the reasons for glass formation and the methods to control them. The glass-forming ability (GFA) of alloys can be substantially increased by a proper selection of alloying elements and the chemical composition of the alloy. High GFA will enable in obtaining large section thickness of amorphous alloys. Ability to produce glassy alloys …
N Multilayer Thin Film Reactions To Form L10 Fept And Exchange Spring Magnets, Bo Yao
N Multilayer Thin Film Reactions To Form L10 Fept And Exchange Spring Magnets, Bo Yao
Electronic Theses and Dissertations
FePt films with the L10 phase have potential applications for magnetic recording and permanent magnets due to its high magnetocrystalline anisotropy energy density. Heat treatment of n multilayer films is one approach to form the L10 FePt phase through a solid state reaction. This thesis has studied the diffusion and reaction of n multilayer films to form the L10 FePt phase and has used this understanding to construct exchange spring magnets. The process-structure-property relations of n multilayer films were systematically examined. The transmission electron microscopy (TEM) study of the annealed multilayers indicates that the Pt layer grows at the expense …
Effect Of Composition, Morphology And Semiconducting Properties On The Efficiency Of Cuin1-Xgaxse2-Ysy Thin-Film Solar Cells Pre, Sachin Kulkarni
Effect Of Composition, Morphology And Semiconducting Properties On The Efficiency Of Cuin1-Xgaxse2-Ysy Thin-Film Solar Cells Pre, Sachin Kulkarni
Electronic Theses and Dissertations
A rapid thermal processing (RTP) reactor for the preparation of graded CuIn1-xGaxSe2-ySy (CIGSeS) thin-film solar cells has been designed, assembled and is being used at the Photovoltaic Materials Laboratory of the Florida Solar Energy Center. CIGSeS films having the optimum composition, morphology, and semiconducting properties were prepared using RTP. Initially films having various Cu/(In+Ga) ratios were prepared. In the next step selenium incorporation in these films was optimized, followed by sulfur incorporation in the surface to increase the bandgap at the surface. The compositional gradient of sulfur was fine-tuned so as to increase the conversion efficiency. Materials properties of these …