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Articles 271 - 300 of 360
Full-Text Articles in Electrical and Electronics
Comparison Of Sparse Coding And Jpeg Coding Schemes For Blurred Retinal Images., Balaji Chandrasekaran
Comparison Of Sparse Coding And Jpeg Coding Schemes For Blurred Retinal Images., Balaji Chandrasekaran
Electronic Theses and Dissertations
Overcomplete representations are currently one of the highly researched areas especially in the field of signal processing due to their strong potential to generate sparse representation of signals. Sparse representation implies that given signal can be represented with components that are only rarely significantly active. It has been strongly argued that the mammalian visual system is highly related towards sparse and overcomplete representations. The primary visual cortex has overcomplete responses in representing an input signal which leads to the use of sparse neuronal activity for further processing. This work investigates the sparse coding with an overcomplete basis set representation which …
Modeling Of Liquid Crystal Display And Photonic Devices, Zhibing Ge
Modeling Of Liquid Crystal Display And Photonic Devices, Zhibing Ge
Electronic Theses and Dissertations
Liquid crystal (LC) materials have been widely applied in electro-optical devices, among which display is the most successful playground and numerous new applications in photonic areas (such as laser beam steering devices) are also emerging. To well guide the device design for optimum performance, accurate modeling is of prior and practical importance. Generally, the modeling of LC devices includes two parts in sequence: accurate LC molecule deformation extraction under external electric fields and optical calculation thereafter for the corresponding electro-optical behaviors. In this dissertation, first, hybrid finite element method and finite difference method are developed to minimize the free energy …
Control And Stabilization Of Laser Plasmasources For Euv Lithography, Jose Cunado
Control And Stabilization Of Laser Plasmasources For Euv Lithography, Jose Cunado
Electronic Theses and Dissertations
Extreme Ultraviolet (EUV) sources rely on droplet laser plasmas for EUV generation. These sources consist of a small (30 µm diameter) droplet which is excited into plasma emitting EUV around 13.5 nm, the industry’s chosen wavelength for EUV lithography (EUVL). These sources are the best candidates for the commercialization of EUVL allowing mass production of computer chips with 32 nm or even smaller feature size. However, the biggest challenges which EUV source developers encounter today are the issues of conversion efficiency (CE) and debris. In order to satisfy the technology requirements, the source will need to meet high levels of …
A Virtual Reality Visualization Ofan Analytical Solution Tomobile Robot Trajectory Generationin The Presence Of Moving Obstacles, Ricardo Elias
A Virtual Reality Visualization Ofan Analytical Solution Tomobile Robot Trajectory Generationin The Presence Of Moving Obstacles, Ricardo Elias
Electronic Theses and Dissertations
Virtual visualization of mobile robot analytical trajectories while avoiding moving obstacles is presented in this thesis as a very helpful technique to properly display and communicate simulation results. Analytical solutions to the path planning problem of mobile robots in the presence of obstacles and a dynamically changing environment have been presented in the current robotics and controls literature. These techniques have been demonstrated using two-dimensional graphical representation of simulation results. In this thesis, the analytical solution published by Dr. Zhihua Qu in December 2004 is used and simulated using a virtual visualization tool called VRML.
High-Intensity Ultra-Fast Laser Interaction Technologies, Robert Thomas Bernath
High-Intensity Ultra-Fast Laser Interaction Technologies, Robert Thomas Bernath
Electronic Theses and Dissertations
To our knowledge this is the first comprehensive study of laser-induced effects generated at intermediate distances using self-channeled femtosecond laser pulses. Studies performed were made both experimentally and theoretically with the use of novel modeling techniques. Peak laser pulse powers above 3 GW allow beam propagation without divergence for up to several kilometers. In this regime, experiments were performed at 30 meters from the laser system in a custom propagation and target range, utilizing the Laser Plasma Laboratory's Terawatt laser system. Experiments included investigations of laser ablation; electromagnetic pulsed (EMP) radiation generation over the 1-18 GHz region; shockwave formation in …
Estimation Of Oceanic Rainfall Using Passive And Active Measurements From Seawinds Spaceborne Microwave Sensor, Khalil Ali Ahmad
Estimation Of Oceanic Rainfall Using Passive And Active Measurements From Seawinds Spaceborne Microwave Sensor, Khalil Ali Ahmad
Electronic Theses and Dissertations
The Ku band microwave remote sensor, SeaWinds, was developed at the National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL). Two identical SeaWinds instruments were launched into space. The first was flown onboard NASA QuikSCAT satellite which has been orbiting the Earth since June 1999, and the second instrument flew onboard the Japanese Advanced Earth Observing Satellite II (ADEOS-II) from December 2002 till October 2003 when an irrecoverable solar panel failure caused a premature end to the ADEOS-II satellite mission. SeaWinds operates at a frequency of 13.4 GHz, and was originally designed to measure the speed and direction of …
Hot Carrier Effect On Ldmos Transistors, Liangjun Jiang
Hot Carrier Effect On Ldmos Transistors, Liangjun Jiang
Electronic Theses and Dissertations
One of the main problems encountered when scaling down is the hot carrier induced degradation of MOSFETs. This problem has been studied intensively during the past decade, under both static and dynamic stress conditions. In this period it has evolved from a more or less academic research topic to one of the most stringent constraints guaranteeing the lifetime of sub-micron devices. New drain engineering technique leads to the extensive usage of lateral doped drain structures. In these devices the peak of the lateral field is lowered by reducing the doping concentration near the drain and by providing a smooth junction …
Discussion On Effective Restoration Of Oral Speech Using Voice Conversion Techniques Based On Gaussian Mixture Modeling, Gustavo Alverio
Discussion On Effective Restoration Of Oral Speech Using Voice Conversion Techniques Based On Gaussian Mixture Modeling, Gustavo Alverio
Electronic Theses and Dissertations
Today's world consists of many ways to communicate information. One of the most effective ways to communicate is through the use of speech. Unfortunately many lose the ability to converse. This in turn leads to a large negative psychological impact. In addition, skills such as lecturing and singing must now be restored via other methods. The usage of text-to-speech synthesis has been a popular resolution of restoring the capability to use oral speech. Text to speech synthesizers convert text into speech. Although text to speech systems are useful, they only allow for few default voice selections that do not represent …
Magnetics Design For High Current Low Voltage Dc/Dc Converter, Hua Zhou
Magnetics Design For High Current Low Voltage Dc/Dc Converter, Hua Zhou
Electronic Theses and Dissertations
With the increasing demand for small and cost efficient DC/DC converters, the power converters are expected to operate with high efficiency. Magnetics components design is one of the biggest challenges in achieving the higher power density and higher efficiency due to the significant portion of magnetics components volume in the whole power system. At the same time, most of the experimental phenomena are related to the magnetics components. So, good magnetics components design is one of the key issues to implement low voltage high current DC/DC converter. Planar technology has many advantages. It has low profile construction, low leakage inductance …
An Analysis Of Misclassification Rates For Decision Trees, Mingyu Zhong
An Analysis Of Misclassification Rates For Decision Trees, Mingyu Zhong
Electronic Theses and Dissertations
The decision tree is a well-known methodology for classification and regression. In this dissertation, we focus on the minimization of the misclassification rate for decision tree classifiers. We derive the necessary equations that provide the optimal tree prediction, the estimated risk of the tree's prediction, and the reliability of the tree's risk estimation. We carry out an extensive analysis of the application of Lidstone's law of succession for the estimation of the class probabilities. In contrast to existing research, we not only compute the expected values of the risks but also calculate the corresponding reliability of the risk (measured by …
High Current Density Low Voltage Isolated Dc-Dc Converterswith Fast Transient Response, Liangbin Yao
High Current Density Low Voltage Isolated Dc-Dc Converterswith Fast Transient Response, Liangbin Yao
Electronic Theses and Dissertations
With the rapid development of microprocessor and semiconductor technology, industry continues to update the requirements for power supplies. For telecommunication and computing system applications, power supplies require increasing current level while the supply voltage keeps decreasing. For example, the Intel's CPU core voltage decreased from 2 volt in 1999 to 1 volt in 2005 while the supply current increased from 20A in 1999 to up to 100A in 2005. As a result, low-voltage high-current high efficiency dc-dc converters with high power-density are demanded for state-of-the-art applications and also the future applications. Half-bridge dc-dc converter with current-doubler rectification is regarded as …
Efficient Algorithms For Correlation Pattern Recognition, Pradeep Ragothaman
Efficient Algorithms For Correlation Pattern Recognition, Pradeep Ragothaman
Electronic Theses and Dissertations
The mathematical operation of correlation is a very simple concept, yet has a very rich history of application in a variety of engineering fields. It is essentially nothing but a technique to measure if and to what degree two signals match each other. Since this is a very basic and universal task in a wide variety of fields such as signal processing, communications, computer vision etc., it has been an important tool. The field of pattern recognition often deals with the task of analyzing signals or useful information from signals and classifying them into classes. Very often, these classes are …
Evaluation Of The Amazon Rain Forest As A Distributed Target For Satellite Microwave Radiometer Calibration, Nishant Patel
Evaluation Of The Amazon Rain Forest As A Distributed Target For Satellite Microwave Radiometer Calibration, Nishant Patel
Electronic Theses and Dissertations
For over three decades, satellite radars have used the Amazon tropical rain forest as a stable homogeneous and isotropic scattering target for calibration. This thesis extends previous work to consider the use of the Amazon as a blackbody target for passive microwave inter-satellite calibration. The characterization of a natural target for radiometric calibration is a formidable task due to the difficulty in obtaining an absolute brightness temperature standard. Previously, multi-frequency microwave brightness temperatures measured by the Tropical Rainfall Measuring Mission Microwave Imager (TMI) were used to provide multi-year observations in local time windows. Our approach differs in that we will …
Steady State And Dynamic Analysis And Optimization Of Single-Stage Power Factor Correction Converters, Khalid Rustom
Steady State And Dynamic Analysis And Optimization Of Single-Stage Power Factor Correction Converters, Khalid Rustom
Electronic Theses and Dissertations
With the increased interest in applying Power Factor Correction (PFC) to off-line AC-DC converters, the field of integrated, single-stage PFC converter development has attracted wide attention. Considering the tens of millions of low-to-medium power supplies manufactured each year for today's rechargeable equipment, the expected reduction in cost by utilizing advanced technologies is significant. To date, only a few single-stage topologies have made it to the market due to the inherit limitations in this structure. The high voltage and current stresses on the components led to reduced efficiency and an increased failure rate. In addition, the component prices tend to increase …
Investigation Of Pn Junction Delineation Resolution Using Electron Beam Induced Current, Christopher Hayden Hontgas
Investigation Of Pn Junction Delineation Resolution Using Electron Beam Induced Current, Christopher Hayden Hontgas
Electronic Theses and Dissertations
This dissertation will investigate electron beam induced current (EBIC) for determining semiconductor material and device parameters. While previous experimental work on PN junction delineation using EBIC with the scanning electron microscope has resulted in resolution to approximately 10 nm, theoretical study shows the potential use of EBIC for higher resolution (nanometer) PN junction and FET channel length delineation using the transmission electron microscope. Theoretical arguments using computer simulations of electron beam generation volume, collection probability and EBIC were performed and are presented for the purpose of determining EBIC use in a 300 keV transmission electron microscope (TEM) for PN junction …
Unified Steady-State Computer Aided Model For Soft-Switching Dc-Dc Converters, Wisam Al-Hoor
Unified Steady-State Computer Aided Model For Soft-Switching Dc-Dc Converters, Wisam Al-Hoor
Electronic Theses and Dissertations
For many decades, engineers and students have heavily depended on simulation packages such as Pspice to run transit and steady-state simulation for their circuits. The majority of these circuits, such as soft switching cells, contain complicated modes of operations that require the Pspice simulation to run for a long time and, finally, it may not reach a convergent solution for these kinds of circuits. Also, there is a need for an educational tool that provides students with a better understanding of circuit modes of operation through state-plan figures and steady-state switching waveforms. The unified steady-state computer aided model proposes a …
Prototype Of Coupling Unit Network For Power Line Communications, Bharath Srinivasan
Prototype Of Coupling Unit Network For Power Line Communications, Bharath Srinivasan
Electronic Theses and Dissertations
Power Line Communications has made impressive strides since its introduction. Power Line Communications (PLC) or Broadband over Power Lines (BPL) is the method of transmitting broadband signals over the power lines and making it available at the power outlet in homes. It provides last mile communication and makes use of existing power lines to transmit signals, thereby eliminating the need to lay cables all over again. PLC is fast becoming a commercial reality in the United States. The Federal Communications Commission (FCC) is working toward making PLC a standard with particular emphasis on power emission issues and interference with nearby …
Hurricane Wind Retrieval Algorithm Development For An Airborne Conical Scanning Scatterometer, Santhosh Vasudevan
Hurricane Wind Retrieval Algorithm Development For An Airborne Conical Scanning Scatterometer, Santhosh Vasudevan
Electronic Theses and Dissertations
Reliable ocean wind vector measurements can be obtained using active microwave remote sensing (scatterometry) techniques. With the increase in the number of severe hurricanes making landfall in the United States, there is increased emphasis on operational monitoring of hurricane winds from aircraft. This thesis presents a data processing algorithm to provide real-time hurricane wind vector retrievals (wind speed and direction) from conically scanning airborne microwave scatterometer measurements of ocean surface backscatter. The algorithm is developed to best suit the specifications for the National Oceanic and Atmospheric Administration (NOAA) Hurricane Research Division's airborne scatterometer Integrated Wind and Rain Airborne Profiler …
Analyis Of Airborne Microwave Polarimetric Radiometer Measurements In The Presence Of Dynamic Platform Attitude Errors, Jean Yves Kabore
Analyis Of Airborne Microwave Polarimetric Radiometer Measurements In The Presence Of Dynamic Platform Attitude Errors, Jean Yves Kabore
Electronic Theses and Dissertations
There are numerous applications for airborne imaging systems in remote sensing, and this thesis deals with a new microwave polarimetric radiometer technique for inferring ocean surface wind direction [3, 5, 7]. This technique is based upon the anisotropy of the polarized ocean blackbody emissions at microwave frequencies relative to the azimuth angle between the microwave radiometer antenna "look" direction and the direction of the wind. Because of the weak wind direction signature, it is important that all systematic brightness temperature (Tb) errors be eliminated, especially those that vary with the radiometer antenna scan position (look direction). This can be accomplished …
Demonstrating Reflectarray Behavior At Infrared, James Ginn
Demonstrating Reflectarray Behavior At Infrared, James Ginn
Electronic Theses and Dissertations
Reflectarrays are traditionally passive, planar microstrip antenna devices designed for reflected phase manipulation at each individual antenna element making up the array. By varying the phase response across the surface with the antenna elements, reflectarrays allows a planar surface to exhibit electromagnetically an arbitrary geometry, such as a spherical surface. Initially proposed as a low-cost replacement for bulky parabolic reflectors, reflectarrays have been successfully developed and utilized at both RF and millimeter-wave frequencies. From the standpoint of an optical systems designer, adapting low-frequency reflectarray technology to develop a sub-millimeter and infrared reflectarray (SMIR) would provide a highly desirable alternative to …
High Speed Turbo Tcm Ofdm For Uwb And Powerline System, Yanxia Wang
High Speed Turbo Tcm Ofdm For Uwb And Powerline System, Yanxia Wang
Electronic Theses and Dissertations
Turbo Trellis-Coded Modulation (TTCM) is an attractive scheme for higher data rate transmission, since it combines the impressive near Shannon limit error correcting ability of turbo codes with the high spectral efficiency property of TCM codes. We build a punctured parity-concatenated trellis codes in which a TCM code is used as the inner code and a simple parity-check code is used as the outer code. It can be constructed by simple repetition, interleavers, and TCM and functions as standard TTCM but with much lower complexity regarding real world implementation. An iterative bit MAP decoding algorithm is associated with the coding …
A Third-Order Differential Steering Robot And Trajectory Generation In The Presence Of Moving Obstacles, Vatana An
Electronic Theses and Dissertations
In this thesis, four robots will be used to implement a collision-free trajectory planning/replanning algorithm. The existence of a chained form transformation so that the robot's model can be control in canonical form will be analyzed and proved. A trajectory generation for obstacles avoidance will be derived, simulated, and implemented. A specific PC based control algorithm will be developed. Chapter two describes two wheels differential drive robot modeling and existence of controllable canonical chained form. Chapter 3 describes criterion for avoiding dynamic objects, a feasible collision-free trajectory parameterization, and solution to steering velocity. Chapter 4 describes robot implementation, pc wireless …
High Slew Rate High-Efficiency Dc-Dc Converter, Xiangcheng Wang
High Slew Rate High-Efficiency Dc-Dc Converter, Xiangcheng Wang
Electronic Theses and Dissertations
Active transient voltage compensator (ATVC) has been proposed to improve VR transient response at high slew rate load, which engages in transient periods operating in MHZ to inject high slew rate current in step up load and recovers energy in step down load. Main VR operates in low switching frequency mainly providing DC current. Parallel ATVC has largely reduced conduction and switching losses. Parallel ATVC also reduces the number of VR bulk capacitors. Combined linear and adaptive nonlinear control has been proposed to reduce delay times in the actual controller, which injects one nonlinear signal in transient periods and simplifies …
Chemical And Biological Treatment Of Mature Landfill Leachate, Eyad Batarseh
Chemical And Biological Treatment Of Mature Landfill Leachate, Eyad Batarseh
Electronic Theses and Dissertations
The challenges imposed on Voltage Regulator Modules (VRM) become difficult to be achieved with the conventional multiphase buck converter commonly used on PC motherboards. For faster data transfer, a decrease in the output voltage is needed. This decrease causes small duty cycle that is accompanied by critical problems which impairs the efficiency. Therefore, these problems need to be addressed. Transformer-based non-isolated topologies are not new approaches to extend the duty cycle and avoid the associated drawbacks. High leakage, several added components and complicated driving and control schemes are some of the trade-offs to expand the duty cycle. The objective of …
Prediction And Measurement Of Radiated Emissions Based On Empirical Time Domain Conducted Measurements, Larry Freeman
Prediction And Measurement Of Radiated Emissions Based On Empirical Time Domain Conducted Measurements, Larry Freeman
Electronic Theses and Dissertations
This thesis develops a novel method to predict radiated emissions measurements. The techniques used are based on standard Electromagnetic Compatibility (EMC) qualification test methods. The empirical data used to formulate the final results was restricted to pertinent data protocol waveforms however the entire method may be applied to any waveforms for which empirical radiated emissions have been measured. The method provides a concise means for predicting worst case radiated emissions profiles based on empirical measured data.
Measuring Optical Turbulence Parameters With A Three-Aperture Receiver, David Wayne
Measuring Optical Turbulence Parameters With A Three-Aperture Receiver, David Wayne
Electronic Theses and Dissertations
This thesis discusses methods to measure several atmospheric parameters related to turbulence. Techniques used by two different scintillometers based on weak turbulence theory are discussed along with a method to estimate the inner scale developed by Hill. The theory and minimization algorithm used to infer the atmospheric parameters are discussed. The main focus is on the analysis and collection of experimental data with a three-aperture receiver system. Intensity fluctuations from a CW laser source are collected over a 1km path with three different receiving apertures. The scintillation index is found for each receiving aperture and recently developed theory for all …
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 …
Pipelining Of Double Precision Floating Point Division And Square Root Operations On Field-Programmable Gate Arrays, Anuja Thakkar
Pipelining Of Double Precision Floating Point Division And Square Root Operations On Field-Programmable Gate Arrays, Anuja Thakkar
Electronic Theses and Dissertations
Many space applications, such as vision-based systems, synthetic aperture radar, and radar altimetry rely increasingly on high data rate DSP algorithms. These algorithms use double precision floating point arithmetic operations. While most DSP applications can be executed on DSP processors, the DSP numerical requirements of these new space applications surpass by far the numerical capabilities of many current DSP processors. Since the tradition in DSP processing has been to use fixed point number representation, only recently have DSP processors begun to incorporate floating point arithmetic units, even though most of these units handle only single precision floating point addition/subtraction, multiplication, …
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 …
Dsp Implementation Of Dc Voltage Regulation Using Adaptive Control For 200 Kw 62000 Rpm Induction Generator, Othman Elkhomri
Dsp Implementation Of Dc Voltage Regulation Using Adaptive Control For 200 Kw 62000 Rpm Induction Generator, Othman Elkhomri
Electronic Theses and Dissertations
The thesis discusses the development of closed loop system to control the DC voltage for 200 kW induction generator rated at a speed of 62000 RPM under different load conditions. The voltage regulation has been implemented using PI controller. A gain scheduling control algorithm has been developed to select the appropriate controller gains with respect to the generator load. Further, a relationship between the generator loads and the controller gains has been established. This relationship has been modeled using adaptive control technique to vary the gains automatically at any load condition. The adaptive control technique has been successfully generalized for …