Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Electrical and Computer Engineering (57)
- Physical Sciences and Mathematics (43)
- Civil and Environmental Engineering (37)
- Electrical and Electronics (29)
- Civil Engineering (25)
-
- Electromagnetics and Photonics (25)
- Optics (25)
- Physics (25)
- Mechanical Engineering (19)
- Computer Sciences (18)
- Computer Engineering (12)
- Materials Science and Engineering (12)
- Environmental Engineering (11)
- Aerospace Engineering (5)
- Engineering Science and Materials (3)
- Navigation, Guidance, Control and Dynamics (1)
- Keyword
-
- Simulation (6)
- Coupling (3)
- Diffusion (3)
- Modeling (3)
- Safety (3)
-
- Training (3)
- Antenna (2)
- Atmosphere (2)
- Augmented reality (2)
- CMOS (2)
- Ceramic (2)
- Conical (2)
- Control (2)
- Diffraction (2)
- EUV (2)
- Ferrate (2)
- Finite Element Method (2)
- HIRad (2)
- Infrared (2)
- Liquid crystal (2)
- Lithography (2)
- Military training (2)
- Oxidation (2)
- Personal computer (2)
- Radiometer (2)
- Reliability (2)
- Rocket (2)
- SFMR (2)
- Scatterometer (2)
- Sensor (2)
Articles 31 - 60 of 189
Full-Text Articles in Engineering
Evaluation Of Prefermentation As A Unit Process Upon Biological Nutrient Removal Including Biokinetic And Wastewater Parameters, Terrence Mccue
Evaluation Of Prefermentation As A Unit Process Upon Biological Nutrient Removal Including Biokinetic And Wastewater Parameters, Terrence Mccue
Electronic Theses and Dissertations
The objective of this dissertation was to provide a controlled comparison of identical continuous flow BNR processes both with and without prefermentation in order to provide a stronger, more quantitative, technical basis for design engineers to evaluate the potential benefits of prefermentation to EBPR in treating domestic wastewater. In addition, the even less understood effect of prefermentation on denitrification kinetics and anoxic phosphorus (P) uptake was studied and quantified. Other aspects of BNR performance, which might change due to use of prefermentation, will also be addressed, including anaerobic stabilization. Potential benefits to BNR processes derived from prefermentation are compared and …
Design And Characterization Of Noveldevices For New Generation Of Electrostaticdischarge (Esd) Protection Structures, Javier Salcedo
Design And Characterization Of Noveldevices For New Generation Of Electrostaticdischarge (Esd) Protection Structures, Javier Salcedo
Electronic Theses and Dissertations
The technology evolution and complexity of new circuit applications involve emerging reliability problems and even more sensitivity of integrated circuits (ICs) to electrostatic discharge (ESD)-induced damage. Regardless of the aggressive evolution in downscaling and subsequent improvement in applications' performance, ICs still should comply with minimum standards of ESD robustness in order to be commercially viable. Although the topic of ESD has received attention industry-wide, the design of robust protection structures and circuits remains challenging because ESD failure mechanisms continue to become more acute and design windows less flexible. The sensitivity of smaller devices, along with a limited understanding of the …
Intrusion Detection In Wireless Sensor Networks, Hong Nhung Nguyen
Intrusion Detection In Wireless Sensor Networks, Hong Nhung Nguyen
Electronic Theses and Dissertations
There are several applications that use sensor motes and researchers continue to explore additional applications. For this particular application of detecting the movement of humans through the sensor field, a set of Berkley mica2 motes on TinyOS operating system is used. Different sensors such as pressure, light, and so on can be used to identify the presence of an intruder in the field. In our case, the light sensor is chosen for the detection. When an intruder crosses the monitored environment, the system detects the changes of the light values, and any significant change meaning that a change greater than …
A Performance Comparison Of Clustering Algorithms In Ad Hocnetworks, Chun Yeung
A Performance Comparison Of Clustering Algorithms In Ad Hocnetworks, Chun Yeung
Electronic Theses and Dissertations
An ad hoc network is comprised of wireless mobile nodes without the need of wired network infrastructure. Due to the limited transmission range of nodes, the exchange of data between them may not be possible using direct communication. Partitioning the network into clusters and electing a clusterhead for each cluster to assist with the resource allocation and data packet transmissions among its members and neighboring clusterheads is one of the most common ways of providing support for the existing ad hoc routing protocols. This thesis presents the performance comparison of four ad hoc network clustering protocols: Dynamic Mobile Adaptive Clustering …
User-Centered Virtual Environment Assessment And Design For Cognitive Rehabilitation Applications, Cali Fidopiastis
User-Centered Virtual Environment Assessment And Design For Cognitive Rehabilitation Applications, Cali Fidopiastis
Electronic Theses and Dissertations
Virtual environment (VE) design for cognitive rehabilitation necessitates a new methodology to ensure the validity of the resulting rehabilitation assessment. We propose that benchmarking the VE system technology utilizing a user-centered approach should precede the VE construction. Further, user performance baselines should be measured throughout testing as a control for adaptive effects that may confound the metrics chosen to evaluate the rehabilitation treatment. To support these claims we present data obtained from two modules of a user-centered head-mounted display (HMD) assessment battery, specifically resolution visual acuity and stereoacuity. Resolution visual acuity and stereoacuity assessments provide information about the image quality …
A New Approach To Identify The Expected Crash Patterns Based On Signalized Intersection Size And Analysis Of Vehicle Movements, Hari Salkapuram
A New Approach To Identify The Expected Crash Patterns Based On Signalized Intersection Size And Analysis Of Vehicle Movements, Hari Salkapuram
Electronic Theses and Dissertations
Analysis of intersection crashes is a significant area in traffic safety research. This study contributes to the area by identifying traffic-geometric characteristics and driver demographics that affect different types of crashes at signalized intersections. A simple methodology to estimate crash frequency at intersections based on the size of the intersection is also developed herein. First phase of this thesis used the crash frequency data from 1,335 signalized intersections obtained from six jurisdictions in Florida, namely, Brevard, Seminole, Dade, Orange, and Hillsborough Counties and the City of Orlando. Using these data a simple methodology has been developed to identify the expected …
Improving Routing Efficiency, Fairness, Differentiated Servises And Throughput In Optical Networks, Bin Zhou
Improving Routing Efficiency, Fairness, Differentiated Servises And Throughput In Optical Networks, Bin Zhou
Electronic Theses and Dissertations
Wavelength division multiplexed (WDM) optical networks are rapidly becoming the technology of choice in next-generation Internet architectures. This dissertation addresses the important issues of improving four aspects of optical networks, namely, routing efficiency, fairness, differentiated quality of service (QoS) and throughput. A new approach for implementing efficient routing and wavelength assignment in WDM networks is proposed and evaluated. In this approach, the state of a multiple-fiber link is represented by a compact bitmap computed as the logical union of the bitmaps of the free wavelengths in the fibers of this link. A modified Dijkstra's shortest path algorithm and a wavelength …
Integrated Inp Photonic Switches, Daniel May-Arrioja
Integrated Inp Photonic Switches, Daniel May-Arrioja
Electronic Theses and Dissertations
Photonic switches are becoming key components in advanced optical networks because of the large variety of applications that they can perform. One of the key advantages of photonic switches is that they redirect or convert light without having to make any optical to electronic conversions and vice versa, thus allowing networking functions to be lowered into the optical layer. InP-based switches are particularly attractive because of their small size, low electrical power consumption, and compatibility with integration of laser sources, photo-detectors, and electronic components. In this dissertation the development of integrated InP photonic switches using an area-selective zinc diffusion process …
Ultrawideband Indoor Location And Tracking System, Qing Chen
Ultrawideband Indoor Location And Tracking System, Qing Chen
Electronic Theses and Dissertations
The objective of this thesis is to demonstrate an indoor intruder location and tracking system with UltraWideBand (UWB) technology and use data compression and Constant False Alarm Rate (CFAR) techniques to improve the performance of the location system. Reliable and accurate indoor positioning requires a local replacement for GPS systems since satellite signals are not available indoors. UWB systems are particularly suitable for indoor location systems due their inherent capabilities such as low-power, multi-path rejection, and wide bandwidth. In our application, we are using UWB radios as a radar system for tracking targets in indoor locations. We also use Discrete …
Experimental Techniques For Nonlinear Material Characterization: A Nonlinear Spectrometer Using A White-Light Continuum Z-Scan, Mihaela Balu
Experimental Techniques For Nonlinear Material Characterization: A Nonlinear Spectrometer Using A White-Light Continuum Z-Scan, Mihaela Balu
Electronic Theses and Dissertations
The main goal of this dissertation is to introduce and demonstrate a new method for the rapid determination of the nonlinear absorption spectra and the dispersion of the nonlinear refraction of optical materials in the visible and near IR spectral regions. However, conventional methods like, white-light continuum pump-probe and Z-scan techniques were used to measure the peak 2PA cross-sections for a number of commercially available photoinitiators. In the new method mentioned above, a high energy, broadband femtosecond white-light continuum is used to replace the single wavelength source conventionally used in a Z-scan experiment. In a Z-scan experiment, the transmittance of …
Polarization-Independent Liquid Crystal Devices, Yi-Hsin Lin
Polarization-Independent Liquid Crystal Devices, Yi-Hsin Lin
Electronic Theses and Dissertations
Liquid crystal (LC) devices can be operated as amplitude modulators and phase modulators. LC amplitude modulation is commonly used in liquid crystal display (LCD) while phase-only modulation is useful for laser beam steering, tunable grating, prism, lens, and other photonic devices. Most LC devices are polarization dependent and require at least one polarizer. As a result, the optical efficiency is low. To enhance display brightness, a power hungry backlight has to be used leading to a high power consumption and short battery life. In a LC phase modulator, the polarization dependent property complicates the laser beam steering system. It is …
A Holistic Usability Framework For Distributed Simulation Systems, Jeffrey Dawson
A Holistic Usability Framework For Distributed Simulation Systems, Jeffrey Dawson
Electronic Theses and Dissertations
This dissertation develops a holistic usability framework for distributed simulation systems (DSSs). The framework is developed considering relevant research in human-computer interaction, computer science, technical writing, engineering, management, and psychology. The methodology used consists of three steps: (1) framework development, (2) surveys of users to validate and refine the framework, and to determine attribute weights, and (3) application of the framework to two real-world systems. The concept of a holistic usability framework for DSSs arose during a project to improve the usability of the Virtual Test Bed, a prototypical DSS, and the framework is partly a result of that project. …
Rf Low Pass Filter Design And Fabrication Using Integrated Passive Device Technology, Heli Li
Rf Low Pass Filter Design And Fabrication Using Integrated Passive Device Technology, Heli Li
Electronic Theses and Dissertations
In this thesis, the whole process of design a low pass filter (LPF) for the wireless communication application has been presented. Integrated passive device technology based on GaAs substrate has been utilized to make the LPF. Schematic simulation and electromagnetic simulations are extensively used in the design process. EM simulation is used in the selection of layout design and processing parameters for design optimization of both the inductors and IPD harmonic filters. The effective use of EM simulation enables us to realize the successful development of high performance harmonic filters. To make the optimization be more flexible and also for …
Multiobjective Simulation Optimization Using Enhanced Evolutionary Algorithm Approaches, Hamidreza Eskandari
Multiobjective Simulation Optimization Using Enhanced Evolutionary Algorithm Approaches, Hamidreza Eskandari
Electronic Theses and Dissertations
In today's competitive business environment, a firm's ability to make the correct, critical decisions can be translated into a great competitive advantage. Most of these critical real-world decisions involve the optimization not only of multiple objectives simultaneously, but also conflicting objectives, where improving one objective may degrade the performance of one or more of the other objectives. Traditional approaches for solving multiobjective optimization problems typically try to scalarize the multiple objectives into a single objective. This transforms the original multiple optimization problem formulation into a single objective optimization problem with a single solution. However, the drawbacks to these traditional approaches …
A Non-Isolated Half Bridge Buck-Based Converter For Vrm Application And Small Signal Modeling Of A Non-Conventional Two Phase Bu, Majd Batarseh
A Non-Isolated Half Bridge Buck-Based Converter For Vrm Application And Small Signal Modeling Of A Non-Conventional Two Phase Bu, Majd Batarseh
Electronic Theses and Dissertations
This dissertation is about treatment of the nonbiodegradable organic content of landfill leachate by chemical oxidation combined with biological treatment. It is divided into three parts. In the first part, ferrate was compared to Fenton's reagent for the purpose of removing non-biodegradable organic compounds from mature leachate. Oxidation conditions (time, pH, and dose) were optimized to yield maximum organic removal using two leachate samples from 20 and 12-year old solid waste cells. Results from this research demonstrated that ferrate and Fenton's reagent had similar optimum pH ranges (3-5), but different organic removal capacities, ranging from 54 to 79 % of …
An Authentic Ecg Simulator, Paul Michalek
An Authentic Ecg Simulator, Paul Michalek
Electronic Theses and Dissertations
An ECG (electrocardiogram) simulator is an electronic tool that plays an essential role in the testing, design, and development of ECG monitors and other ECG equipment. Principally an ECG simulator provides ECG monitors with an electrical signal that emulates the human heart's electrical signal so that the monitor can be tested for reliability and important diagnostic capabilities. However, the current portable commercially available ECG simulators are lacking in their ability to fully test ECG monitors. Specifically, the portable simulators presently on the market do not produce authentic ECG signals but rather they endeavor to create the ECG signals mathematically. They …
Effect Of Operator Control Configuration On Unmanned Aerial System Trainability, John Neumann
Effect Of Operator Control Configuration On Unmanned Aerial System Trainability, John Neumann
Electronic Theses and Dissertations
Unmanned aerial systems (UAS) carry no pilot on board, yet they still require live operators to handle critical functions such as mission planning and execution. Humans also interpret the sensor information provided by these platforms. This applies to all classes of unmanned aerial vehicles (UAV's), including the smaller portable systems used for gathering real-time reconnaissance during military operations in urban terrain. The need to quickly and reliably train soldiers to control small UAS operations demands that the human-system interface be intuitive and easy to master. In this study, participants completed a series of tests of spatial ability and were then …
Efficient Large Scale Transient Heat Conduction Analysis Using A Parallelized Boundary Element Method, Kevin Erhart
Efficient Large Scale Transient Heat Conduction Analysis Using A Parallelized Boundary Element Method, Kevin Erhart
Electronic Theses and Dissertations
A parallel domain decomposition Laplace transform Boundary Element Method, BEM, algorithm for the solution of large-scale transient heat conduction problems will be developed. This is accomplished by building on previous work by the author and including several new additions (most note-worthy is the extension to 3-D) aimed at extending the scope and improving the efficiency of this technique for large-scale problems. A Laplace transform method is utilized to avoid time marching and a Proper Orthogonal Decomposition, POD, interpolation scheme is used to improve the efficiency of the numerical Laplace inversion process. A detailed analysis of the Stehfest Transform (numerical Laplace …
An Improved Microwave Radiative Transfer Model For Ocean Emissivity At Hurricane Force Surface Wind Speed, Salem El-Nimri
An Improved Microwave Radiative Transfer Model For Ocean Emissivity At Hurricane Force Surface Wind Speed, Salem El-Nimri
Electronic Theses and Dissertations
An electromagnetic model for predicting the microwave blackbody emission from the ocean surface under the forcing of strong surface winds in hurricanes is being developed. This ocean emissivity model will be incorporated into a larger radiative transfer model used to infer ocean surface wind speed and rain rate in hurricanes from remotely sensed radiometric brightness temperature. The model development is based on measurements obtained with the Stepped Frequency Microwave Radiometer (SFMR), which routinely flys on the National Oceanic and Atmospheric Administration's hurricane hunter aircraft. This thesis presents the methods used in the wind speed model development and validation results for …
Hurricane Wind Speed And Rain Rate Retrieval Algorithm For The Stepped Frequency Microwave Radiometer, Ruba Amarin
Hurricane Wind Speed And Rain Rate Retrieval Algorithm For The Stepped Frequency Microwave Radiometer, Ruba Amarin
Electronic Theses and Dissertations
This thesis presents the development and validation of the Hurricane Imaging Retrieval Algorithm (HIRA) for the measurement of oceanic surface wind speed and rain rate in hurricanes. The HIRA is designed to process airborne microwave brightness temperatures from the NOAA, Stepped Frequency Microwave Radiometer (SFMR), which routinely collects data during NOAA hurricane hunter aircraft flights. SFMR measures wind speeds and rain rates at nadir only, but HIRA will soon be integrated with an improved surface wind speed model for expanded utilization with next generation microwave hurricane imagers, such as the Hurricane Imaging Radiometer (HIRad). HIRad will expand the nadir only …
Safety Effects Of Traffic Signal Installations On State Road Intersections In Northeast Florida, Christopher Ledew
Safety Effects Of Traffic Signal Installations On State Road Intersections In Northeast Florida, Christopher Ledew
Electronic Theses and Dissertations
The purpose of this thesis is to explore how the installations of traffic signals affect crash experience at intersections, to identify those factors which help predict crashes after a signal is installed, and to develop a crash prediction model. It is the intent of this thesis to supplement the Manual on Uniform Traffic Control Devices Signal Warrant procedure and aid the traffic engineer in the signal installation decision making process. Crash data, as well as operational and geometric factors were examined for 32 state road intersections in the northeast Florida area before and after signal installation. Signal warrant studies were …
A Three-Dimensional Bay/Estuary Model To Simulate Water Quality Transport, Jing Yu
A Three-Dimensional Bay/Estuary Model To Simulate Water Quality Transport, Jing Yu
Electronic Theses and Dissertations
This thesis presents the development of a numerical water quality model using a general paradigm of reaction-based approaches. In a reaction-based approach, all conceptualized biogeochemical processes are transformed into a reaction network. Through the decomposition of species governing equations via Gauss-Jordan column reduction of the reaction network, (1) redundant fast reactions and irrelevant kinetic reactions are removed from the system, which alleviates the problem of unnecessary and erroneous formulation and parameterization of these reactions, and (2) fast reactions and slow reactions are decoupled, which enables robust numerical integrations. The system of species transport equations is transformed to reaction-extent transport equations, …
Wide Viewing Angle Liquid Crystal Displays, Qi Hong
Wide Viewing Angle Liquid Crystal Displays, Qi Hong
Electronic Theses and Dissertations
In this dissertation, novel phase compensation technologies are applied to the designs of wide viewing angle and high transmittance liquid crystal displays. First, a design of wide viewing angle liquid crystal displays utilizing crossed linear polarizers is proposed. The designed multi-domain vertical-alignment liquid crystal display predicts superb contrast ratio over wide viewing angles. Next, to increase the bright state transmittance while maintain the high contrast. Finally, to reduce the cost and improve the applicability of the broadband and wide-view circular polarizer, the device configuration of the broadband and wide-view circular polarizer is significantly simplified by the application of biaxial compensation …
On The Use Of Variable Coherence In Inverse Scattering Problems, Erwan Baleine
On The Use Of Variable Coherence In Inverse Scattering Problems, Erwan Baleine
Electronic Theses and Dissertations
Even though most of the properties of optical fields, such as wavelength, polarization, wavefront curvature or angular spectrum, have been commonly manipulated in a variety of remote sensing procedures, controlling the degree of coherence of light did not find wide applications until recently. Since the emergence of optical coherence tomography, a growing number of scattering techniques have relied on temporal coherence gating which provides efficient target selectivity in a way achieved only by bulky short pulse measurements. The spatial counterpart of temporal coherence, however, has barely been exploited in sensing applications. This dissertation examines, in different scattering regimes, a variety …
Verification Of Faa's Emissions And Dispersion Modeling System (Edms), Anjoli Martin
Verification Of Faa's Emissions And Dispersion Modeling System (Edms), Anjoli Martin
Electronic Theses and Dissertations
Air quality has been a major environmental concern for many years. Recently the issue of airport emissions has presented growing concerns and is being studied in much more depth. Airport emissions come from a variety of point, line and area sources, making emissions modeling for airports very complex and more involved. Accurate air quality models, specific to airport needs, are required to properly analyze this complex array of air pollution sources created by airports. Accurate air quality models are needed to plan for increased growth of current airports and address concerns over proposed new ones. The Federal Aviation Administration's (FAA) …
Finite Element Method Modeling Of Advanced Electronic Devices, Yupeng Chen
Finite Element Method Modeling Of Advanced Electronic Devices, Yupeng Chen
Electronic Theses and Dissertations
In this dissertation, we use finite element method together with other numerical techniques to study advanced electron devices. We study the radiation properties in electron waveguide structure with multi-step discontinuities and soft wall lateral confinement. Radiation mechanism and conditions are examined by numerical simulation of dispersion relations and transport properties. The study of geometry variations shows its significant impact on the radiation intensity and direction. In particular, the periodic corrugation structure exhibits strong directional radiation. This interesting feature may be useful to design a nano-scale transmitter, a communication device for future nano-scale system. Non-quasi-static effects in AC characteristics of carbon …
Pervious Concrete: A Hydrologic Analysis For Stormwater Management Credit, Joshua Spence
Pervious Concrete: A Hydrologic Analysis For Stormwater Management Credit, Joshua Spence
Electronic Theses and Dissertations
Portland Cement pervious concrete's ability to permit water infiltration has encouraged its use as a stormwater management tool. However, the material has suffered historically poor support due to a number of factors, including failures due to poor mix design and improper construction techniques, concern about lesser structural strength, concern about poor long term performance due to clogging of surface pores and undefined credit for stormwater management. This study focuses on long term performances of pervious concrete parking lots and their stormwater management credit. Before stormwater management credit could be estimated, it was necessary to develop a testing device to gather …
Coupling Of Hydrodynamic And Wave Models For Storm Tide Simulations: A Case Study For Hurricane Floyd (1999), Yuji Funakoshi
Coupling Of Hydrodynamic And Wave Models For Storm Tide Simulations: A Case Study For Hurricane Floyd (1999), Yuji Funakoshi
Electronic Theses and Dissertations
This dissertation presents the development of a two-dimensional St. Johns River model and the coupling of hydrodynamic and wave models for the simulation of storm tides. The hydrodynamic model employed for calculating tides and surges is ADCIRC-2DDI (ADvanced CIRCulation Model for Shelves, Coasts and Estuaries, Two-Dimensional Depth Integrated) developed by Luettich et al. (1992). The finite element based model solves the fully nonlinear shallow water equations in the generalized wave continuity form. Hydrodynamic applications are operated with the following forcings: 1) astronomical tides, 2) inflows from tributaries, 3) meteorological effects (winds and pressure), and 4) waves (wind-induced waves). The wave …
Cognitive Training Transfer Using A Personal Computer-Based Game:A Close Quarters Battle Case Study, Michael Woodman
Cognitive Training Transfer Using A Personal Computer-Based Game:A Close Quarters Battle Case Study, Michael Woodman
Electronic Theses and Dissertations
Developers of Commercial off the Shelf (COTS) gaming software are making remarkable strides in increasing the realism of their software. This realism has caught the attention of the training community, which has traditionally sought system and operational replication in training systems such as flight simulators. Since games are designed and marketed for entertainment and not designed for training of tasks, questions exist about the effectiveness of games as a training system in achieving the desired transfer of skills to the actual environment. Numerous studies over the past ten years have documented that PC-based simulation training environments can offer effective training …
Ultrashort, High Power, And Ultralow Noise Mode-Locked Optical Pulse Generation Using Quantum-Dot Semiconductor Lasers, Myoung-Taek Choi
Ultrashort, High Power, And Ultralow Noise Mode-Locked Optical Pulse Generation Using Quantum-Dot Semiconductor Lasers, Myoung-Taek Choi
Electronic Theses and Dissertations
This dissertation explores various aspects and potential of optical pulse generation based on active, passive, and hybrid mode-locked quantum dot semiconductor lasers with target applications such as optical interconnect and high speed signal processing. Design guidelines are developed for the single mode operation with suppressed reflection from waveguide discontinuities. The device fabrication procedure is explained, followed by characteristics of FP laser, SOA, and monolithic two-section devices. Short pulse generation from an external cavity mode-locked QD two-section diode laser is studied. High quality, sub-picosecond (960 fs), high peak power (1.2 W) pulse trains are obtained. The sign and magnitude of pulse …