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Articles 31 - 47 of 47
Full-Text Articles in Engineering
Discrete Wave Propagation In Quadratically Nonlinear Media, Robert Iwanow
Discrete Wave Propagation In Quadratically Nonlinear Media, Robert Iwanow
Electronic Theses and Dissertations
Discrete models are used in describing various microscopic phenomena in many branches of science, ranging from biology through chemistry to physics. Arrays of evanescently coupled, equally spaced, identical waveguides are prime examples of optical structures in which discrete dynamics can be easily observed and investigated. As a result of discretization, these structures exhibit unique diffraction properties with no analogy in continuous systems. Recently nonlinear discrete optics has attracted a growing interest, triggered by the observation of discrete solitons in AlGaAs waveguide arrays reported by Eisenberg et al. in 1998. So far, the following experiments involved systems with third order nonlinearities. …
Rr Interval Estimation From An Ecg Using A Linear Discrete Kalman Filter, Arun Janapala
Rr Interval Estimation From An Ecg Using A Linear Discrete Kalman Filter, Arun Janapala
Electronic Theses and Dissertations
An electrocardiogram (ECG) is used to monitor the activity of the heart. The human heart beats seventy times on an average per minute. The rate at which a human heart beats can exhibit a periodic variation. This is known as heart rate variability (HRV). Heart rate variability is an important measurement that can predict the survival after a heart attack. Studies have shown that reduced HRV predicts sudden death in patients with Myocardial Infarction (MI). The time interval between each beat is called an RR interval, where the heart rate is given by the reciprocal of the RR interval expressed …
Study Of Oxide Breakdown, Hot Carrier And Nbti Effects On Mos Device And Circuit Reliability, Yi Liu
Study Of Oxide Breakdown, Hot Carrier And Nbti Effects On Mos Device And Circuit Reliability, Yi Liu
Electronic Theses and Dissertations
As CMOS device sizes shrink, the channel electric field becomes higher and the hot carrier (HC) effect becomes more significant. When the oxide is scaled down to less than 3 nm, gate oxide breakdown (BD) often takes place. As a result, oxide trapping and interface generation cause long term performance drift and related reliability problems in devices and circuits. The RF front-end circuits include low noise amplifier (LNA), local oscillator (LO) and mixer. It is desirable for a LNA to achieve high gain with low noise figure, a LO to generate low noise signal with sufficient output power, wide tuning …
Detection Of The R-Wave In Ecg Signals, Sasanka Valluri
Detection Of The R-Wave In Ecg Signals, Sasanka Valluri
Electronic Theses and Dissertations
This thesis aims at providing a new approach for detecting R-waves in the ECG signal and generating the corresponding R-wave impulses with the delay between the original R-waves and the R-wave impulses being lesser than 100 ms. The algorithm was implemented in Matlab and tested with good results against 90 different ECG recordings from the MIT-BIH database. The Discrete Wavelet Transform (DWT) forms the heart of the algorithm providing a multi-resolution analysis of the ECG signal. The wavelet transform decomposes the ECG signal into frequency scales where the ECG characteristic waveforms are indicated by zero crossings. The adaptive threshold algorithms …
A New Hybrid Diffractive Photo-Mask Technology, Jin Won Sung
A New Hybrid Diffractive Photo-Mask Technology, Jin Won Sung
Electronic Theses and Dissertations
In the field of photolithography for micro-chip manufacturing, the photo-mask is used to print desired patterns on a proper photo-resist on wafer. The most common type of photo-mask is binary amplitude mask made an opaque layer of chrome. The principle and potential application of hybrid photo-mask with diffractive phase element and binary amplitude is presented in this dissertation paper from both numerical modeling and experimental research. The first important application is the characterization of aberration in the stepper system using hybrid diffractive photo-mask. By utilizing multiple diffractive illumination conditions, it is possible to characterize Zernike wave front aberration coefficients up …
System Design And Optimization Of Optical Coherence Tomography, Avni Ceyhun Akcay
System Design And Optimization Of Optical Coherence Tomography, Avni Ceyhun Akcay
Electronic Theses and Dissertations
Optical coherence imaging, including tomography (OCT) and microscopy (OCM), has been a growing research field in biomedical optical imaging in the last decade. In this imaging modality, a broadband light source, thus of short temporal coherence length, is used to perform imaging via interferometry. A challenge in optical coherence imaging, as in any imaging system towards biomedical diagnosis, is the quantification of image quality and optimization of the system components, both a primary focus of this research. We concentrated our efforts on the optimization of the imaging system from two main standpoints: axial point spread function (PSF) and practical steps …
Analysis And Design Of Miniaturized Rf Saw Duplexer Package, Hao Dong
Analysis And Design Of Miniaturized Rf Saw Duplexer Package, Hao Dong
Electronic Theses and Dissertations
This dissertation provides a comprehensive methodology for accurate analysis and design of miniaturized radio frequency (RF) surface acoustic wave (SAW) duplexer package. Full-wave analysis based on the three dimensional (3-D) finite element method (FEM) is successfully applied to model the package. The die model is obtained by combining the acoustics and die busbars parasitics models. The acoustics model is obtained using the coupling-of-models (COM) technique. The die busbars, bonding wires and printed circuit board (PCB) are modeled using full-wave analysis. After that, the models of package, die, and bonding wires are assembled together to get the total response. To take …
Design And Implementation Of Wireles Sensor Networks For Parking Management System, Sudhir Chandrasekar Kora
Design And Implementation Of Wireles Sensor Networks For Parking Management System, Sudhir Chandrasekar Kora
Electronic Theses and Dissertations
The technology of wirelessly networked micro sensors promises to revolutionize the way we interact with the physical environment. A new approach to solve parking-related issues of vehicles in parking lots using wireless sensor networks is presented. This approach enables the implementation of the Parking Management System (PMS®) in public parking lots found in Airports, Commercial Buildings, Universities, etc. The design architecture of the sensor nodes is discussed here. An overall view of the sensor network, which covers the whole of the parking lot, is also summarized. Detailed description of the software architecture that supports the hardware is provided. A sample …
Seawinds Radiometer Brightness Temperature Calibration And Validation, Mayank Rastogi
Seawinds Radiometer Brightness Temperature Calibration And Validation, Mayank Rastogi
Electronic Theses and Dissertations
The NASA SeaWinds scatterometer is a radar remote sensor which operates on two satellites; NASA's QuikSCAT launched in June 1999 and on Japan's ADEOS-II satellite launched in December 2002. The purpose of SeaWinds is to provide global measurements of the ocean surface wind vector. On QuikSCAT, a ground data processing algorithm was developed, which allowed the instrument to function as a QuikSCAT Radiometer (QRad) and measure the ocean microwave emissions (brightness temperature, Tb) simultaneously with the backscattered power. When SeaWinds on ADEOS was launched, this same algorithm was applied, but the results were anomalous. The initial SRad brightness temperatures exhibited …
Stabilization And Tracking Of The Van Der Pol Oscillator, Xin Zhao
Stabilization And Tracking Of The Van Der Pol Oscillator, Xin Zhao
Electronic Theses and Dissertations
In this thesis, the stabilization and tracking problem of the Van der Pol oscillator is studied by using advanced control techniques. First, the linear state feedback and linear adaptive state feedback controllers for the stabilization problem are designed. Then, non-linear state feedback and output feedback controllers are proposed for the tracking problem with known parameters. Finally, a dynamic output feedback controller based on adaptive backstepping technique is introduced for the tracking problem when all parameters of the Van der Pol system are unknown.
Speaker Identification Based On Discriminative Vector Quantization And Data Fusion, Guangyu Zhou
Speaker Identification Based On Discriminative Vector Quantization And Data Fusion, Guangyu Zhou
Electronic Theses and Dissertations
Speaker Identification (SI) approaches based on discriminative Vector Quantization (VQ) and data fusion techniques are presented in this dissertation. The SI approaches based on Discriminative VQ (DVQ) proposed in this dissertation are the DVQ for SI (DVQSI), the DVQSI with Unique speech feature vector space segmentation for each speaker pair (DVQSI-U), and the Adaptive DVQSI (ADVQSI) methods. The difference of the probability distributions of the speech feature vector sets from various speakers (or speaker groups) is called the interspeaker variation between speakers (or speaker groups). The interspeaker variation is the measure of template differences between speakers (or speaker groups). All …
Control And Topology Improvements In Half-Bridge Dc-Dc Converters, Songquan Deng
Control And Topology Improvements In Half-Bridge Dc-Dc Converters, Songquan Deng
Electronic Theses and Dissertations
Efficiency and transient response are two key requirements for DC-DC converters. Topology and control are two key topics in this dissertation. A variety of techniques for DC-DC converter performance improvement are presented in this work. Focusing on the efficiency issue, a variety of clamping techniques including both active and passive methods are presented after the ringing issues in DC-DC converters are investigated. By presenting the clamping techniques, a big variety of energy management concepts are introduced. The active bridge-capacitor tank clamping and FET-diode-capacitor tank clamping are close ideas, which transfer the leakage inductor energy to clamping capacitor to prevent oscillation …
Background Stabilization And Motion Detection In Launch Pad Video Monitoring, Kaushik Gopalan
Background Stabilization And Motion Detection In Launch Pad Video Monitoring, Kaushik Gopalan
Electronic Theses and Dissertations
Automatic detection of moving objects in video sequences is a widely researched topic with application in surveillance operations. Methods based on background cancellation by frame differencing are extremely common. However this process becomes much more complicated when the background is not completely stable due to camera motion. This thesis considers a space application where surveillance cameras around a shuttle launch site are used to detect any debris from the shuttle. The ground shake due to the impact of the launch causes the background to be shaky. We stabilize the background by translation of each frame, the optimum translation being determined …
Design Of A Dynamic Focusing Microscope Objective For Oct Imaging, Supraja Murali
Design Of A Dynamic Focusing Microscope Objective For Oct Imaging, Supraja Murali
Electronic Theses and Dissertations
Optical Coherence Tomography (OCT) is a novel optical imaging technique that has assumed significant importance in bio-medical imaging in the last two decades because it is non-invasive and provides accurate, high resolution images of three dimensional cross-sections of body tissue, exceeding the capabilities of the current predominant imaging technique ultrasound. In this thesis, high resolution OCT is investigated for in vivo detection of abnormal skin pathology for the early diagnosis of cancer. The technology presented is based on a dynamic focusing microscopic imaging probe conceived for skin imaging and the detection of abnormalities in the epithelium. A novel method for …
High Gain / Broadband Oxide Glasses For Next Generation Raman Amplifiers, Clara Rivero
High Gain / Broadband Oxide Glasses For Next Generation Raman Amplifiers, Clara Rivero
Electronic Theses and Dissertations
Interest in Raman amplification has undergone a revival due to the rapidly increasing bandwidth requirements for communications transmission, both for long haul and local area networks, and recent developments in the telecom fiber industry and diode laser technology. In contrast to rare earth doped fiber amplifiers, for which the range of wavelengths is fixed and limited, Raman gain bandwidths are larger and the operating wavelength is fixed only by the pump wavelength and the bandwidth of the Raman active medium. In this context, glasses are the material of choice for this application due to their relatively broad spectral response, and …
Preparation And Characterization Of Cigss Solar Cells And Pv Module Data Analysis, Jyoti Shirolikar
Preparation And Characterization Of Cigss Solar Cells And Pv Module Data Analysis, Jyoti Shirolikar
Electronic Theses and Dissertations
In this thesis, multiple activities have been carried out in order to improve the process of CIGSS solar cell fabrication on a 4" x 4" substrate. The process of CIGSS solar cell fabrication at FSEC's PV Materials Lab involves a series of steps that were all carried out manually in the past. A LABVIEW program has been written to carry out automated sputter deposition of Mo back contact, CuGa, In metallic precursors on a soda lime glass substrate using a stepper motor control for better uniformity. Further, selenization/ sulfurization of these precursors was carried out using rapid thermal processing (RTP). …
New Optimal High Efficiency Dsp-Based Digital Controller Design For Super High-Speed Permanent Magnet Synchronous Motor, Limei Zhao
Electronic Theses and Dissertations
This dissertation investigates digital controller and switch mode power supply design for super high-speed permanent magnet synchronous motors (PMSM). The PMSMs are a key component for the miniaturic cryocooler that is currently under development at the University of Central Florida with support from NASA Kennedy Space Center and the Florida Solar Energy Center. Advanced motor design methods, control strategies, and rapid progress in semiconductor technology enables production of a highly efficient digital controller. However, there are still challenges for such super high-speed controller design because of its stability, high-speed, variable speed operation, and required efficiency over a wide speed range. …