Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Physical Sciences and Mathematics (3)
- Artificial Intelligence and Robotics (2)
- Computer Sciences (2)
- Materials Science and Engineering (2)
- Analytical Chemistry (1)
-
- Automotive Engineering (1)
- Bioelectrical and Neuroengineering (1)
- Biomedical (1)
- Biomedical Engineering and Bioengineering (1)
- Chemistry (1)
- Computer Engineering (1)
- Electro-Mechanical Systems (1)
- Engineering Science and Materials (1)
- Manufacturing (1)
- Mechanical Engineering (1)
- Mechanics of Materials (1)
- Other Electrical and Computer Engineering (1)
- Polymer and Organic Materials (1)
- Robotics (1)
- Semiconductor and Optical Materials (1)
- Keyword
-
- Modeling (7)
- Reliability (7)
- Remote sensing (7)
- Machine learning (6)
- Power electronics (6)
-
- Radiometer (6)
- UWB (6)
- Antenna (5)
- Control (5)
- Digital control (5)
- LDMOS (5)
- Laser (5)
- Radio frequency (5)
- Algorithms (4)
- Artificial intelligence (4)
- Calibration (4)
- Computer vision (4)
- Electric discharges (4)
- MPPT (4)
- Microwave Remote Sensing (4)
- Multiagent systems (4)
- Power Electronics (4)
- Power amplifiers (4)
- Radar (4)
- Radiometers (4)
- SFMR (4)
- Simulation (4)
- Transient response (4)
- WindSat (4)
- Action recognition (3)
- Publication Year
- Publication
- Publication Type
Articles 211 - 240 of 359
Full-Text Articles in Electrical and Electronics
Delay Modeling And Long-Range Predictive Control Of Czochralski Growth Process, Dhaval Shah
Delay Modeling And Long-Range Predictive Control Of Czochralski Growth Process, Dhaval Shah
Electronic Theses and Dissertations
This work presents the Czochralski growth dynamics as time-varying delay based model, applied to the growth of La3Ga5.5Ta0.5O14 (LGT) piezoelectric crystals. The growth of high-quality large-diameter oxides by Czochralski technique requires the theoretical understanding and optimization of all relevant process parameters, growth conditions, and melts chemistry. Presently, proportional-integral- derivative (PID) type controllers are widely accepted for constant-diameter crystal growth by Czochralski. Such control systems, however, do not account for aspects such as the transportation delay of the heat from crucible wall to the crystal solidification front, heat radiated from the crucible wall above the melt surface, and varying melt level. …
Pulse Frequency Modulation Zcs Flyback Converter In Inverter Applications, Feng Tian
Pulse Frequency Modulation Zcs Flyback Converter In Inverter Applications, Feng Tian
Electronic Theses and Dissertations
Renewable energy source plays an important role in energy co-generation and distribution. A traditional solar-based inverter system has two stages cascaded, which has 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 synchronizing sinusoid current into the utility grid. In Chapter 1, the characteristic I-V and P-V curve of PV array has been illustrated. Based on prediction of the PV power capacity installed on the grid-connected and off-grid, the trends of grid-tied inverter for DG system have been analyzed. In Chapter 2, …
Efficiency Improvement Techniques For High Voltage Capacitor Charging Methods, Michael Islas
Efficiency Improvement Techniques For High Voltage Capacitor Charging Methods, Michael Islas
Electronic Theses and Dissertations
The goal of this thesis is to design and fabricate a DC-to-DC converter for use in high-voltage capacitor charging applications. The primary objectives include increasing the efficiency and reducing the cost of traditional methods used for this application. Traditional methods were not designed specifically for high-voltage capacitor charging and were thus very primitive and exhibited lower efficiency. Prior methods made use of a high voltage power supply and a current limiting resistor or control scheme. The power supply would often only operate efficiently at a single voltage value and would thus function poorly over a range used in charging a …
Design And Modeling Of Radiation Hardened Lateral Power Mosfets, Matthew Landowski
Design And Modeling Of Radiation Hardened Lateral Power Mosfets, Matthew Landowski
Electronic Theses and Dissertations
Galactic-cosmic-rays (GCR) exist in space from unknown origins. A cosmic ray is a very high energy electron, proton, or heavy ion. As a GCR transverses a power semiconductor device, electron-hole-pairs (ehps) are generated along the ion track. Effects from this are referred to as single-event-effects (SEEs). A subset of a SEE is single-event burnout (SEB) which occurs when the parasitic bipolar junction transistor is triggered leading to thermal runaway. The failure mechanism is a complicated mix of photo-generated current, avalanche generated current, and activation of the inherent parasitic bipolar transistor. Current space-borne power systems lack the utility and advantages of …
Simulation Of Brightness Temperatures For The Microwave Radiometer On The Aquarius/Sac-D Mission., Salman Khan
Simulation Of Brightness Temperatures For The Microwave Radiometer On The Aquarius/Sac-D Mission., Salman Khan
Electronic Theses and Dissertations
Microwave radiometers are highly sensitive receivers capable of measuring low levels of natural blackbody microwave emissions. Remote sensing by satellite microwave radiometers flying on low-earth, polar orbiting, satellites can infer a variety of terrestrial and atmospheric geophysical parameters for scientific and operational applications, such as weather and climate prediction. The objective of this thesis is to provide realistic simulated ocean brightness temperatures for the 3-channel Microwave Radiometer (MWR), which will be launched in May 2010 on the joint NASA/CONAE Aquarius/SAC-D Mission. These data will be used for pre-launch geophysical retrieval algorithms development and validation testing. Analyses are performed to evaluate …
Control Of Nonh=Holonomic Systems, Hongliang Yuan
Control Of Nonh=Holonomic Systems, Hongliang Yuan
Electronic Theses and Dissertations
Many real-world electrical and mechanical systems have velocity-dependent constraints in their dynamic models. For example, car-like robots, unmanned aerial vehicles, autonomous underwater vehicles and hopping robots, etc. Most of these systems can be transformed into a chained form, which is considered as a canonical form of these nonholonomic systems. Hence, study of chained systems ensure their wide applicability. This thesis studied the problem of continuous feed-back control of the chained systems while pursuing inverse optimality and exponential convergence rates, as well as the feed-back stabilization problem under input saturation constraints. These studies are based on global singularity-free state transformations and …
Magnetically Deflectable Mems Actuators For Optical Sensing Applications, Matthew Montgomery
Magnetically Deflectable Mems Actuators For Optical Sensing Applications, Matthew Montgomery
Electronic Theses and Dissertations
In this work, new small deflection magnetic actuators have been proposed, designed, and tested for applications in Surface Enhanced Raman Scattering optical sensors. Despite the fact that SERS sensors have been shown to increase Raman over ten orders of magnitude for molecular detection, several technological challenges have prevented the design of practical sensors, such as making SERS sensors that can efficiently detect a wide variety of molecules. Since the optimum signal-to-noise in SERS occurs at different excitation wavelengths for different molecules, individual metal nanostructures need to be designed and fabricated for each independent chemical species. One possible solution to this …
Unsupervised Building Detection From Irregularly Spaced Lidar And Aerial Imagery, Nicholas Shorter
Unsupervised Building Detection From Irregularly Spaced Lidar And Aerial Imagery, Nicholas Shorter
Electronic Theses and Dissertations
As more data sources containing 3-D information are becoming available, an increased interest in 3-D imaging has emerged. Among these is the 3-D reconstruction of buildings and other man-made structures. A necessary preprocessing step is the detection and isolation of individual buildings that subsequently can be reconstructed in 3-D using various methodologies. Applications for both building detection and reconstruction have commercial use for urban planning, network planning for mobile communication (cell phone tower placement), spatial analysis of air pollution and noise nuisances, microclimate investigations, geographical information systems, security services and change detection from areas affected by natural disasters. Building detection …
Study Of Gate Oxide Breakdown And Hot Electron Effect On Cmos Circuit Performances, Jun Ma
Study Of Gate Oxide Breakdown And Hot Electron Effect On Cmos Circuit Performances, Jun Ma
Electronic Theses and Dissertations
In the modern semiconductor world, there is a significant scaling of the transistor dimensions--The transistor gate length and the gate oxide thickness drop down to only several nanometers. Today the semiconductor industry is already dominated by submicron devices and other material devices for the high transistor density and performance enhancement. In this case, the semiconductor reliability issues are the most important thing for commercialization. The major reliability issues caused by voltage are hot carrier effects (HCs) and gate oxide breakdown (BD) effects. These issues are recently more important to industry, due to the small size and high lateral field in …
Validation Of Quickscat Radiometer (Qrad) Microwave Brightness Temperture Measurments, Rafik Hanna
Validation Of Quickscat Radiometer (Qrad) Microwave Brightness Temperture Measurments, Rafik Hanna
Electronic Theses and Dissertations
After the launch of NASA's SeaWinds scatterometer in 1999, a radiometer function was implemented in the Science Ground Data Processing Systems to allow the measurement of the earth's microwave brightness temperature. This dissertation presents results of a comprehensive validation to assess the quality of QRad brightness temperature measurements using near-simultaneous ocean Tb comparisons between the SeaWinds on QuikSCAT (QRad) and WindSat polarimetric radiometer on Coriolis. WindSat was selected because it is a well calibrated radiometer that has many suitable collocations with QuikSCAT; and it has a 10.7 GHz channel, which is close to QRad frequency of 13.4 GHz. Brightness temperature …
An Improved Hurrican Wind Vector Retrieval Algorithm Using Sea Winds Scatterometer, Peth Laupattarakasem
An Improved Hurrican Wind Vector Retrieval Algorithm Using Sea Winds Scatterometer, Peth Laupattarakasem
Electronic Theses and Dissertations
Over the last three decades, microwave remote sensing has played a significant role in ocean surface wind measurement, and several scatterometer missions have flown in space since early 1990's. Although they have been extremely successful for measuring ocean surface winds with high accuracy for the vast majority of marine weather conditions, unfortunately, the conventional scatterometer cannot measure extreme winds condition such as hurricane. The SeaWinds scatterometer, onboard the QuikSCAT satellite is NASA's only operating scatterometer at present. Like its predecessors, it measures global ocean vector winds; however, for a number of reasons, the quality of the measurements in hurricanes are …
Phase Shaping In The Infrared By Planar Quasi-Periodic Surfaces Comprised Of Sub-Wavelength Elements, James Ginn
Phase Shaping In The Infrared By Planar Quasi-Periodic Surfaces Comprised Of Sub-Wavelength Elements, James Ginn
Electronic Theses and Dissertations
Reflectarrays are passive quasi-periodic sub-wavelength antenna arrays designed for discrete reflected phase manipulation at each individual antenna element making up the array. By spatially varying the phase response of the antenna array, reflectarrays allow a planar surface to impress a non-planar phasefront upon re-radiation. Such devices have become commonplace at radio frequencies. In this dissertation, they are demonstrated in the infrared for the first time--at frequencies as high as 194 THz. Relevant aspects of computational electromagnetic modeling are explored, to yield design procedures optimized for these high frequencies. Modeling is also utilized to demonstrate the phase response of a generalized …
A Statistical Approach To View Synthesis, Phillip Berkowitz
A Statistical Approach To View Synthesis, Phillip Berkowitz
Electronic Theses and Dissertations
View Synthesis is the challenging problem of predicting a new view or pose of an object given an exemplar view or set of views. This thesis presents a novel approach for the problem of view synthesis. The proposed method uses global features rather than local geometry to achieve an effect similar to that of the well known view morphing method . While previous approaches to the view synthesis problem have shown impressive results, they are highly dependent on being able to solve for epipolar geometry and therefore have a very precise correspondence between reference images. In cases where this is …
Realization Of Power Factor Correction And Maximum Power Point Tracking For Low Power Wind Turbines, Gustavo Gamboa
Realization Of Power Factor Correction And Maximum Power Point Tracking For Low Power Wind Turbines, Gustavo Gamboa
Electronic Theses and Dissertations
In recent years, wind energy technology has become one of the top areas of interest for energy harvesting in the power electronics world. This interest has especially peaked recently due to the increasing demand for a reliable source of renewable energy. In a recent study, the American Wind Energy Association (AWEA) ranked the U.S as the leading competitor in wind energy harvesting followed by Germany and Spain. Although the United States is the leading competitor in this area, no one has been able successfully develop an efficient, low-cost AC/DC convertor for low power turbines to be used by the average …
Nonlinear Stabilization And Control Of Medium Range Surface To Air Interceptor Missiles, Mark Snyder
Nonlinear Stabilization And Control Of Medium Range Surface To Air Interceptor Missiles, Mark Snyder
Electronic Theses and Dissertations
Nonlinear stabilization and control autopilots are capable of sustaining nominal performance throughout the entire fight envelope an interceptor missile may encounter during hostile engagements and require no gain scheduling to maintain autopilot stability. Due to non minimum phase conditions characteristic of tail controlled missile airframes, a separation of time scales within the dynamic equations of motion between rotational and translational differential equations was enforced to overcome unstable effects of non minimum phase. Dynamic inversion techniques are then applied to derive linearizing equations which, when injected forward into the plant result in a fully controllable linear system. Objectives of the two …
Saw Reflective Transducers And Antennas For Orthogonal Frequency Coded Saw Sensors, Bianca Maria Santos
Saw Reflective Transducers And Antennas For Orthogonal Frequency Coded Saw Sensors, Bianca Maria Santos
Electronic Theses and Dissertations
Passive sensors that vary its impedance per measured parameter may be used with surface acoustic wave (SAW) reflective transducers (SRT) for wireless acquisition of the measurand. The device is composed of two transducers, where one, which may be attached to an antenna, is used to launch the wave within the device substrate, and the other is where the sensor load is attached to. The latter is able to reflect the incident wave. How much power is reflected is determined by the attached sensor load. Amplitude variations as well as peak frequency variations of the SRT reflectivity response are explored in …
Physical Properties Of Wave Scattering By Chiral Periodic Structure, Xiaomin Yang
Physical Properties Of Wave Scattering By Chiral Periodic Structure, Xiaomin Yang
Electronic Theses and Dissertations
Attention has been focused on electromagnetic chirality and its potential applications to microwave, millimeter wave and optical wave devices. In this work, wave propagation through a chiral periodic structure with arbitrary shape is investigated. Although perturbation theory and coupled-mode theory have been used to analyze chiral periodic structure, those are approximate methods and can only be used for low frequency applications. In this work, the rigorous mode-matching method is used to solve the problem. Staircase approximation is introduced to change the curved structure to a multilayer structure. The field solutions in the uniform air regions and unbounded air-chiral periodic array …
Reaction Velocities In Free Standing Aluminum And Cooper Oxide This Films, Matthew Erickson
Reaction Velocities In Free Standing Aluminum And Cooper Oxide This Films, Matthew Erickson
Electronic Theses and Dissertations
In this work we investigate the reaction propagation velocity of aluminum and copper oxide Metastable Intermolecular Composites (MIC's). All samples were deposited in a magnetron sputtering system using 2 aluminum targets and 2 copper targets. The copper is sputtered in an oxygen rich environment in order to obtain copper oxide rich films. Three different layer structures are used for various measurements that are composed of alternating 20 layer pairs, 30 layer pairs, and 40 layer pairs. All layer pairs maintain a constant total thickness of 3.2 microns. Each layer structure can be prepared independent of a substrate and is measured …
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 …
Ultra-Wide Band In Communications: Performance Analysis And Enhancements, Burak Berksoy
Ultra-Wide Band In Communications: Performance Analysis And Enhancements, Burak Berksoy
Electronic Theses and Dissertations
Over the last ten years, Ultra-Wide Band (UWB) technology has attracted tremendous research attention. Frequency allocation of 3.1-10.6 GHz for UWB application by FCC made it apparent that UWB will be the technology for future wireless high speed communication applications. With the promise of high data rates (high channel capacity), UWB also offers advantages such as communication security, high multi-path resolution, good penetration capability, ability to coexist with other communication schemes in the same band, and finally, circuit simplicity. The theoretical advantages of UWB has made it a great candidate for short distance communications, however, UWB communications have many challenges, …
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 …
Modeling And Analysis Of Power Mosfets For High Frequency Dc-Dc Converters, Yali Xiong
Modeling And Analysis Of Power Mosfets For High Frequency Dc-Dc Converters, Yali Xiong
Electronic Theses and Dissertations
Evolutions in integrated circuit technology require the use of a high-frequency synchronous buck converter in order to achieve low cost, low profile, fast transient response and high power density. However, high frequency operation leads to increased power MOSFET switching losses. Optimization of the MOSFETs plays an important role in improving converter performance. This dissertation focuses on revealing the power loss mechanism of power MOSFETs and the relationship between power MOSFET structure and its power loss. The analytical device model, combined with circuit modeling, cannot reveal the relationship between device structure and its power loss due to the highly non-linear characteristics …
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, 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 …
Audio And Video Tempo Analysis For Dance Detection, Ryan Faircloth
Audio And Video Tempo Analysis For Dance Detection, Ryan Faircloth
Electronic Theses and Dissertations
The amount of multimedia in existence has become so extensive that the organization of this data cannot be performed manually. Systems designed to maintain such quantity need superior methods of understanding the information contained in the data. Aspects of Computer Vision deal with such problems for the understanding of image and video content. Additionally large ontologies such as LSCOM are collections of feasible high-level concepts that are of interest to identify within multimedia content. While ontologies often include the activity of dance it has had virtually no coverage in Computer Vision literature in terms of actual detection. We will demonstrate …
Inter-Satellite Microwave Radiometer Calibration, Liang Hong
Inter-Satellite Microwave Radiometer Calibration, Liang Hong
Electronic Theses and Dissertations
The removal of systematic brightness temperature (Tb) biases is necessary when producing decadal passive microwave data sets for weather and climate research. It is crucial to achieve Tb measurement consistency among all satellites in a constellation as well as to maintain sustained calibration accuracy over the lifetime of each satellite sensor. In-orbit inter-satellite radiometric calibration techniques provide a long term, group-wise solution; however, since radiometers operate at different frequencies and viewing angles, Tb normalizations are made before making intermediate comparisons of their near-simultaneous measurements. In this dissertation, a new approach is investigated to perform these normalizations from one satellite's measurements …
Comparison Of Theoretical Models Of Power Spectral Density To The Experimental Value For Spectrum Of Irradiance Fluctuations, Craig Hershberger
Comparison Of Theoretical Models Of Power Spectral Density To The Experimental Value For Spectrum Of Irradiance Fluctuations, Craig Hershberger
Electronic Theses and Dissertations
A propagation experiment was designed, assembled, and conducted on an extended range to verify theoretical temporal models for weak to strong fluctuation theory. Laser light intensity was propagated over terrain at the Kennedy Space Center (Florida), and detected using optical receivers at a distance of 13.3 Km from the optical source. The intensity data from the experiment was used to generate an experimental Power Spectral Density (PSD) function. The theoretical Mutual Coherence Function (MCF) and Wave Structure Function (WSF) as set forth by Andrews/Phillips , were evaluated to determine the effective relationship between the statistical moments of the random optical …
Data Communication With A Nano-Satellite Using Satellite Personal Communication Networks (S-Pcns), Khudeja Khan
Data Communication With A Nano-Satellite Using Satellite Personal Communication Networks (S-Pcns), Khudeja Khan
Electronic Theses and Dissertations
Satellites typically communicate with locations on the ground to receive commands and send data back. Establishing reliable communications generally requires dedicated ground stations, which in turn require hardware and expertise. Developers of nano-satellites, however, may not have the expertise or resources necessary for establishing a dedicated ground station. Therefore, the use of an existing communication system, such as the Satellite Personal Communication Networks (S-PCNs), is attractive. Another shortcoming of the fixed ground stations, already available, is that they are normally only able to communicate with Low Earth Orbit (LEO) nano-satellites four times per day (two10-minute windows separated by 90 minutes, …
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 …