Electrical and Computer Engineering Commons^™

Distributed Sensor Fault Diagnosis For Automated Highway Systems, Hui Chen

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Fault diagnosis problems for large-scale nonlinear systems have attracted significant attentions from researchers in recent years. Most fault detection and isolation (FDI) methods have been proposed based on a centralized architecture. However, due to the complexity of the system, most of these centralized fault detection and diagnosis schemes are not able to delivery effective fault detection and isolation performance for a large-scale nonlinear system, which contains subsystems interacting with neighboring subsystems.

In this thesis, a distributed fault detection and isolation method is developed for the automated highway systems (AHS). For each subsystem of AHS, a distributed fault detection and isolation …

Design And Fabrication Of An Eddy Current Brake Dynamometer For Efficiency Determination Of Electric Wheelchair Motors, Wesley Brin

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Electric wheelchairs have a considerable impact on improving the quality of life for the millions of disabled persons around the world. These modern pieces of technology offer freedom and mobility for disabled persons to interact with the world outside of their homes. The goal of this project is to assist in advancements of conventional electric wheelchairs. This includes replacing the heavy, bulky, and inefficient lead acid batteries and worm gear drive systems with lithium-ion batteries and wheel hub motors in order to decrease weight and size, and increase efficiency. This master thesis research is focused on designing, fabricating, and testing …

Timing And Power Optimization Using Mixed-Dynamic-Static Cmos, Hao Xue

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An effective approach to timing and power optimization for single clocking and multiple clocking dynamic CMOS designs is presented in this thesis. For the single-clocking scheme dynamic CMOS sub-blocks can be replaced by static CMOS and mixed-dynamic-static CMOS for power minimization. For the multiple-clocking scheme the delay of data ready for use plays more important role than its clock pulse in timing optimization. Power minimization can be achieved by implementing dynamic CMOS sub-blocks with static or mixed-dynamic-static CMOS. In comparison with the benchmark 16-bit carry select adder in dynamic CMOS, the critical path delay is reduced by 41.1% using the …

An Accuracy Improvement Method For Cricket Indoor Location System, Anall Vijaykumar Gandhi

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The effective deployment of Automated Guided Vehicles (AGV) in indoor hostile environment demands high precision localization for navigation purposes. The cricket system, based on Time Difference of Arrival (TDoA) approach, provides precise localization. It calculates TDoA between radio and ultrasonic signal to estimate distance between two cricket motes. The position, in the referenced coordinate system, is estimated by multilateration using estimated distances from multiple motes. Therefore, the position accuracy depends on the distance estimation which in turn depends on the TDoA calculation. Ultrasonic transducer, a component of cricket mote hardware, has highly directive radiation pattern which affects ultrasonic signal detection. …

Selective Free-Standing Through-Wafer Porous Silicon Membrane (Sftpsm) For Integrated Meta-Material Devices, Bella Liu Yao

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Meta-materials have attracted considerable attention due to their unique electromagnetic properties, such as negative permittivity (ε), negative magnetic permeability (μ), and negative index of refraction. These devices have shown broad flexibility in compact phase shifter, backward leaky-wave antenna, and high-directivity coupled-line coupler applications; however, integrated devices utilizing meta-material structures have not yet surfaced due to a lack of integration technology.

In this work, a novel concept of integrated meta-materials is presented, using free-standing porous silicon (PS) membranes of periodic magnetic wire arrays (PMWA). The free-standing PS membranes were fabricated on p-type silicon substrates through electrochemical anodization. Systematic investigations have been …

Analysis Of Human Echolocation Waveform For Radar Target Recognition, Kandarp Patel

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Some blind humans have developed the remarkable capability of echolocation, similar to the type used by mammals such as the bat, dolphin and whale. This population of human has shown the ability to classify targets based on their location, size, shape and material in diverse environmental conditions simply by listening to the reflected echoes of tongue clicks generated by their mouth. To date, much of the research into human echolocation has been confined exclusively to behavioral science and the analysis is inconsistent with the approaches used in engineering. The waveforms used in current radar systems appear different to those typical …

Software-Defined Radio Based Blind Hierarchical Modulation Detector Via Second-Order Cyclostationary And Fourth-Order Cumulant, Yang Qu

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Modulation detection is very important to many communication and electronic warfare applications. Recent developments in cognitive radio (CR) and dynamic spectrum access (DSA) network have also brought much attention to modulation detection of unknown radio frequency (RF) signals. It is well known that using second-order cyclostationary features, e.g., spectral correlation function (SCF) and spectral coherent function (SOF), BPSK modulation can be easily distinguished from higher order modulations such as QPSK and QAM modulations. However, QPSK and higher order modulations exhibit similar second-order cyclostationary features, thus these features cannot be employed to distinguish among higher order modulations. To classify higher order …

Non-Contact Probes For Characterization Of Thz Devices And Components, Mads Jacob Hedegaard Larsen

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One of the challenges in developing semiconductor devices and integrated circuits for the terahertz (THz) region is their electrical characterization. The most common technology for their characterization is presently metal-to-metal, DC-coupled contact probes, which operate up to 750 GHz but are expensive and fragile.

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In this Master's Thesis, we investigate through numerical simulation and analysis the electromagnetic properties of a novel, AC-coupled probe. The new probe couples radiation from the device or circuit-under-test (DUT) via polarization current, which is then transformed to conduction current in the probe and down-converted in frequency to baseband by an optically-pumped photomixer. Finite-element simulations …

Stability Of A Fuzzy Logic Based Piecewise Linear Hybrid System, Aaron W. Seyfried

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Complex cyber-physical systems are difficult to model and control. However, humans are capable of accomplishing these tasks by constantly adapting and redefining the rules to control these complex systems. Fuzzy logic provides a means of encoding human inference into a control methodology. However, the fuzzy logic controllers are nonlinear and their stability is difficult to verify. Therefore, the widespread usefulness of fuzzy logic controllers is limited. It has been proven that fuzzy logic controllers can be implemented as piecewise linear switched controllers. It has also been shown that the piecewise linear system can be implemented as a hybrid system. Piecewise …

Frequency Characterization Of Si, Sic, And Gan Mosfets Using Buck Converter In Ccm As An Application, Keshava Gopalakrishna

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Present day applications using power electronic converters are focusing towards improving the speed, efficiency, and robustness. This led to the implementation of new devices in such converters where speed and efficiency are of concern. As silicon (Si) based power devices are approaching their operational performance limits with respect to speed, it is essential to analyze the properties of new devices, which are capable of replacing silicon based devices. Wide band-gap (WBG) semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) are such materials, whose material properties show promising advantages for power electronic applications.

This thesis focuses on the …

High-K Material Based Leaky-Wave Antenna Design, Implementation, And Manufacture, Jiahui Wang

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Leaky-wave antennas are a class of antennas which apply a traveling wave on a guiding structure as the main radiation mechanism. The properties of leaky-wave antennas are light weight, easy to fabricate, and readily integrated into conventional millimeter-wave systems. These features make leaky-wave antennas attractive. The most important characteristic is that the antenna can steer the beam direction through changing the operating frequency rather than switching the antenna itself. Variety types of leaky-wave antennas have been introduced and developed during the past 70 years. However, there is no existing leaky-wave antenna which can widely steer the beam scanning angle by …

Characterization Of Doped Gallium Nitride Substrates, Jack Lee Owsley Iii

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In this thesis the characteristics of five bulk semi-insulated doped gallium nitride samples provided by Kyma Technologies, Inc were explored. The five GaN samples were grown on sapphire substrates by hydride vapor phase epitaxy (HVPE) and doped with different concentrations of iron, hydrogen, carbon, oxygen and silicon. The first step of characterization was measuring the optical absorption of all the samples using a UV-NIR fiber spectrometer. Through this procedure it was found that they all showed a strong absorption at 518 nm. Thus, time-resolved differential transmission measurements were conducted at this wavelength using the second harmonic generation (SHG) of a …

Nano-Scale Rf/Microwave Characterization Of Materials' Electromagnetic Properties, Joshua Allen Myers

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There are two words that describe the direction of today's electronic technology, smaller and faster. With the ever decreeing size scientists and engineers must have a way to characterize materials in the nm range. In this thesis characterization of nano-materials is discussed based on scanning probe microscopy and an in-depth look at RF/microwave frequencies by scanning microwave microscopy. Recently, low-temperature spin-sprayed ferrite films (Fe3O4) with a high self-biased magnetic anisotropy field have been reported, showing FMR frequency>5 GHz. Such films hold great potential for RF/microwave devices and find immediate applications. In this study, we performed in situ scanning microwave …

A Unified Nonlinear Adaptive Approach For The Fault Diagnosis Of Aircraft Engines, Remus C. Avram

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In this thesis, a fault detection and isolation (FDI) method is developed for aircraft engines by utilizing nonlinear adaptive estimation techniques. Engine sensor faults, actuator faults and component faults are considered under one unified framework. The fault diagnosis architecture consists of a bank of nonlinear adaptive estimators. One of them is the fault detection estimator used for fault detection, and the remaining ones are fault isolation estimators employed to determine the particular fault type/location after fault detection. Each isolation estimator is designed based on the functional structure of a particular fault type under consideration. The FDI architecture has been integrated …

Mapping Algorithm For Autonomous Navigation Of Lawn Mower Using Sick Laser, Shashidhar Baichbal

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The objective of this thesis is to present a mapping algorithm for autonomous navigation of a lawnmower based on the range and bearing information of a SICK laser. The Simultaneous Localization and Mapping (SLAM) algorithm is a tool that can be used to navigate unmanned vehicle in an unknown environment. The two-dimensional (2D) maps of the obstacles can be obtained if the laser scans the environment in a plane horizontal to the ground. However, the 2D map does not give information of the objects that are placed below the height of the laser. This makes it difficult for the lawn …

Structural And Electronic Properties Of Two-Dimensional Silicene, Graphene, And Related Structures, Ruiping Zhou

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Traditional CMOS (complementary metal-oxide-semiconductor) transistors have already been in the nanometer range. As bulk silicon material is approaching its physical limits, it is highly desirable to seek novel, functional materials to continue Moore's law. Two-dimensional(2D) materials, such as graphene and silicene, have attracted great attention since they were envisioned a few years ago, having extraordinary electrical properties. Research in this work was focused on understanding the structural and electronic properties of a few atomic layers of carbon (graphene) and silicon (silicene). Atomic structures of the 2D materials, corresponding band structures, and transport properties were calculated based on density functional theory. …

Ultra Low Power Read-Out Integrated Circuit Design, Jian Chen

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Carbon nanotubes (CNTs) are widely studied by the researchers in recent years, as they have small size, large strength, highly electrical and thermal conductivity. The single-walled CNT (SWNT) is readily changed in electrical resistance when exposed to gas, and has significant use in environmental monitoring, agriculture and fishing industry, chemical industry and even security. A read-out integrated circuit (ROIC) is required to detect the resistive change. In this thesis, an ultra-low power, wide dynamic detecting range and small size CMOS ROIC design is presented. This ROIC can interface wide dynamic range signal up to more than two orders (100pA-60nA) from …

Digital Wideband Spectral Sensing Receiver, Lawrence D. Burich

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Detecting, channelizing, and characterizing radio frequency signals is a fundamental requirement for electronic warfare receivers as well as in commercial wireless applications where it is important to determine activity/inactivity in specified bands for spectral sharing and interference avoidance. Spectral sensing receivers are required to cover bandwidths in the GHz range and channelize signals into frequency bins in the kilo-hertz or mega-hertz range depending on the application. The difficulty is to detect, then determine spectral characteristics of multiple signals with varying power levels and signal characteristics in real time. A number of current Digital Wideband Spectral Sensing Receiver (DWSSR) architectures are …

Integrity Monitoring Techniques For Vision Navigation Systems, Nicholas Allen Baine

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In aviation applications, navigation integrity is paramount. Integrity of GPS systems is well established with set standards. Vision based navigation systems have been found to be an adequate substitute for GPS, when it is unavailable but are unlikely to be utilized until there is a measure for system integrity. Work has been done to detect the effect of a single measurement pair being corrupted with a bias; however, the measurement geometry varies greatly with the environment. The environment could be sparse in visual features to track, or the environment could be rich with features. With more features, there is a …

Prediction Of Optimal Bayesian Classification Performance For Ladar Atr, Kristjan H. Greenewald

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We consider the problem of LADAR ATR classifier performance prediction in the presence of arbitrary nuisance parameters including but not limited to pose. We use several noise models for both range images and point clouds that are significantly more accurate and complex than the Gaussian models used by previous non-Monte Carlo prediction methods. Two accurate new methods of efficiently predicting the optimum Bayesian classification performance are then derived, and applied to the noise models. Advantages of these methods include significant gains in accuracy for medium to high noise levels and the ability to handle target near symmetry. Extensions are developed …

Adaptive Noise Reduction Techniques For Airborne Acoustic Sensors, Ryan Michael Fuller

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Ground and marine based acoustic arrays are currently employed in a variety of military and civilian applications for the purpose of locating and identifying sources of interest. An airborne acoustic array could perform an identical role, while providing the ability to cover a larger area and pursue a target. In order to implement such a system, steps must be taken to attenuate environmental noise that interferes with the signal of interest. In this thesis, we discuss the noise sources present in an airborne environment, present currently available methods for mitigation of these sources, and propose the use of adaptive noise …

Extension Of Polar Format Scene Size Limits To Squinted Geometries, Matthew Steven Horvath

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The Polar Format Algorithm (PFA) is an often used algorithm to image synthetic aperture radar (SAR) phase history data. The algorithm relies on a far-field approximation wherein the curved wavefront of the transmitted pulses is approximated as a planar wavefront, introducing spatially variant phase errors in the phase history. While allowing for faster image formation compared to more exact imaging algorithms such as convolution backprojection, these phase errors lead to the distortion and defocus of point targets, degrading the quality of the resulting imaged scene.

Historically, a Taylor expansion has been used to approximate the phase errors leading to distortion …

Uhf-Sar And Lidar Complementary Sensor Fusion For Unexploded Buried Munitions Detection, Randy S. Depoy Jr.

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Given the UHF bands properties of foliage and round penetration, a UHF-SAR image contains both above- and below-surface scatterers. The problem of detecting sub-surface objects is problematic due to the presence of above-surface scatterers in the detection images. In case of a single-pass anomaly image or a two-pass change image, the resulting anomalies or changes are due to scatterers above and below the surface, where the above surface anomalies/changes act as confusers. LIDAR digital elevation models (DEM) provide georegistered information about the above-surface objects present in the UHF-SAR scene. Detection of the above-surface objects in the LIDAR domain is used …

Compact Leaky Wave Antenna Using Ferroelectric Materials, Hyung Min Jeon

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Leaky wave antenna continuously attracts a lot interests for tuning the radiation direction over a large angle. Various types of leaky wave antenna have been developed since 1940. However, most of these leaky wave antennas suffered from their excessive volume and the required wide range of operating frequency (bandwidth) to achieve a large tuning angle. To circumvent these challenges, research in this thesis is focused on implementation of material (like PZT) with high dielectric constant (k) in a rectangular waveguide leaky wave antenna. Due to the high dielectric constant of PZT ~ 1,900, the propagation wavelength in the waveguide can …

Characterization Of Room Temperature Terahertz Direct Detectors, Carla Renee Boggs

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Room temperature direct detectors operating in the so-called Terahertz (THz) region of the electromagnetic spectrum, and representing the most common detection technologies currently available, were characterized at 104, 280 GHz or 600 GHz within their intended range of operating frequencies. These detectors included commercial Schottky-diode rectifiers (Virginia Diodes and Spacek Labs), commercial pyroelectric detectors (Spectrum Detector), and a commercial Golay cell (QMCI). The characterization included antenna patterns, responsivity, electrical noise, noise equivalent temperature difference (NEΔT ), and noise equivalent power (NEP). Since all the characterization measurements were made the same way, quantitative comparisons can be made between the performances of …

Direct Digital Frequency Synthesizer Architecture For Wireless Communication In 90 Nm Cmos Technology, Tri Trong Nguyen

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Software radio is one promising field that can meet the demands for low cost, low power, and high speed electronic devices for wireless communication. At the heart of software radio is a programmable oscillator called a Direct Digital Synthesizer (DDS). DDS has the capabilities of rapid frequency hopping by digital software control while operating at very high frequencies and having sub-hertz resolution. Nevertheless, the digital-to-analog converter (DAC) and the read-only-memory (ROM) look-up table, building blocks of the DDS, prevent the DDS to be used in wireless communication because they introduce errors and noises to the DDS and their performances deteriorate …

Design Of A Low Power And Area Efficient Digital Down Converter And Sinc Filter In Cmos 90-Nm Technology, Steven John Billman

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A digital down converter (DDC) typically receives a digital input that has been generated by an analog to digital converter (ADC) operating at intermediate frequency (IF) in an RF receiver chain. The function of the DDC is to down convert the IF signal to baseband in phase (I) and quadrature (Q) signals and is a very important component in wireless receivers. A Digital Down Converter (DDC) is developed based on square wave local oscillators facilitating a multiplier-less implementation with no constraints on the sampling frequency. The DDC includes a pseudo multi-rate SINC low pass filter which exhibits better performance compared …

Structured Silicon Macropore As Anode In Lithium Ion Batteries, Xida Sun

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Porous silicon (PS) membranes for lithium-ion batteries (LIBs) anode applications were developed, demonstrated and characterized systematically in this work. Electrochemical measurements were conducted on both Si-wafer supported and free-standing porous Si membranes. It turned out that the specific capacity of LIBs was enhanced remarkably by PS based anode. PS was fabricated by using electrochemical anodization in a mixed solution of Dimethylformamide (DMF) and Hydrofluoric acid (HF wt.49%). By varying the anodization conditions, including HF concentration, anodization etching time and current density, pores were formed in a p-type (1-20Ω cm) boron-doped silicon substrate. Scanning electron microscopy (SEM) was employed to investigate …

Circuit Techniques On Improving Timing And Noise In Dynamic Cmos, Arvind Vaidyanadeswaran

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Dynamic CMOS are widely employed in high-performance CMOS chips due to high speed and less area in comparison with Static CMOS. However, Dynamic CMOS circuits are inherently less noise tolerant than Static CMOS circuits. This problem becomes more severe with aggressive technology scaling into nanometer process, particularly caused by the charge sharing, the sub-threshold leakage current, the power rail noise and the crosstalk noise. In this thesis, circuit techniques on improving both timing and noise of Dynamic CMOS are presented. A comparison with previous reported work is also presented. Simulations proved that the proposed circuit techniques can achieve a high …

Real-Time Fault Diagnosis Of Automotive Electrical Power Generation And Storage System, Luis Farfan-Ramos

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Automobiles depend more and more on electric power. Analysis of warranty data by automotive OEMs shows that faults in the automotive electrical power generation and storage (EPGS) system are often misdiagnosed. Therefore, monitoring of the state of health (SOH) of the automotive EPGS system is vital for early and correct diagnosis of faults in it, ensuring a reliable supply of electric power to the vehicle and reducing maintenance costs. In this research project, a model-based SOH monitoring method for the EPGS system is developed without the requirement of an alternator current sensor. A model representing the dynamic relationship between the …