Electrical and Electronics Commons^™

Oxide Defect Engineering Methods For Valence Change (Vcm) Resistive Random Access Memories, Jihan Ocampo Capulong

Legacy Theses & Dissertations (2009 - 2024)

Electrical switching requirements for resistive random access memory (ReRAM) devices are multifaceted, based on device application. Thus, it is important to obtain an understanding of these switching properties and how they relate to the oxygen vacancy concentration and oxygen vacancy defects. Oxygen vacancy defects in the switching oxide of valence-change-based ReRAM (VCM ReRAM) play a significant role in device switching properties. Oxygen vacancies facilitate resistive switching as they form the conductive filament that changes the resistance state of the device. This dissertation will present two methods of modulating the defect concentration in VCM ReRAM composed of Pt/HfO_x/Ti stack: …

Development Of A One-Dimensional Position Sensitive Detector For Tracking Applications, Leigh Kent Lydecker

Legacy Theses & Dissertations (2009 - 2024)

Optical Position Sensitive Detectors (PSDs) are a non-contact method of tracking the location of a light spot. Silicon-based versions of such sensors are fabricated with standard CMOS processing, are inexpensive and provide a real-time, analog signal output corresponding to the position of the light spot. Because they are non-contact, they do not degrade over time from surface friction due to repetitive sliding motion associated with standard full contact sliding potentiometers. This results in long, reliable device lifetimes. In this work, an innovative PSD was developed to replace the linear hard contact potentiometer currently being used in a human-computer interface architecture.

Cross-Layer Capacity Optimization In Ofdma Systems: Wimax And Lte, Bimal Paudel

Electronic Theses and Dissertations

Given the broad range of applications supported, high data rate required and low latency promised; dynamic radio resource management is becoming vital for newly emerging air interface technologies such as wireless interoperability for microwave access (Wimax) and long term evolution (lte) adopted by international standards. This thesis considers orthogonal frequency division multiple access (ofdma) system, which has been implemented in both Wimax and lte technologies as their air interface multiple access mechanism. A framework for optimized resource allocation with quality of service (qos) support that aims to balance between service provider's revenue and subscriber's satisfaction is proposed. A cross-layer optimization …

Optimized Image Compressed Sensing And Transmission Through Wireless Channels, Saheed Olanigan

Electronic Theses and Dissertations

This thesis examines the robust behavior of quantized compressed sensing measurements during transmission through an additive white gaussian noise wireless channel. The poor rate-distortion performance that accompanies compressed sensing after applying quantization has led to several works in quantized compressed sensing. However, most of these works have less consideration of the effect of transmission channel on the resulting bit stream of the quantized compressed sensing measurements. For an additive white gaussian noise wireless channel model, the quantizer and bit energy signal-to-noise ratio determines the degree of the channel effect. This thesis explores the effect of quantization and channel noise during …

Energy Optimization Of A Free-Piston Enhanced Hybrid Vehicle, Kenneth Jarod Jones

Dissertations

The world’s heavy dependence on vehicles which utilize hydrocarbon fuels as a primary power source has renewed the interest in electric and hybrid vehicles for industrial, commercial, and public use. The primary objective of this movement is centered on increased efficiency in energy usage for transportation. Hybrid vehicles which utilize an internal combustion engine as a linear generator, converting energy stored in hydrocarbon fuels into electrical power, could serve as a transitioning technology. The free-piston enhanced hybrid vehicle (FPHV) could potentially fill this role. The present work contains a theoretical and numerical approach to analyzing and optimizing the usage of …

3d Printed Electromagnetic Transmission And Electronic Structures Fabricated On A Single Platform Using Advanced Process Integration Techniques, Paul I. Deffenbaugh

Open Access Theses & Dissertations

3D printing has garnered immense attention from many fields including in-office rapid prototyping of mechanical parts, outer-space satellite replication, garage functional firearm manufacture, and NASA rocket engine component fabrication. 3D printing allows increased design flexibility in the fabrication of electronics, microwave circuits and wireless antennas and has reached a level of maturity which allows functional parts to be printed. Much more work is necessary in order to perfect the processes of 3D printed electronics especially in the area of automation. Chapter 1 shows several finished prototypes of 3D printed electronics as well as newly developed techniques in fabrication. Little is …

Control Based Soft Switching Three-Phase Micro-Inverter: Efficiency And Power Density Optimization, Ahmadreza Amirahmadi

Electronic Theses and Dissertations

In the field of renewable energy, solar photovoltaic is growing exponentially. Grid-tied PV micro-inverters have become the trend for future PV system development because of their remarkable advantages such as enhanced energy production due to MPPT implementation for each PV panel, high reliability due to redundant and distributed system architecture, and simple design, installation, and management due to its plug-and-play feature. Conventional approaches for the PV micro-inverters are mainly in the form of single-phase grid connected and they aim at the residential and commercial rooftop applications. It would be advantageous to extend the micro-inverter concept to large size PV installations …

Learning Collective Behavior In Multi-Relational Networks, Xi Wang

Electronic Theses and Dissertations

With the rapid expansion of the Internet and WWW, the problem of analyzing social media data has received an increasing amount of attention in the past decade. The boom in social media platforms offers many possibilities to study human collective behavior and interactions on an unprecedented scale. In the past, much work has been done on the problem of learning from networked data with homogeneous topologies, where instances are explicitly or implicitly inter-connected by a single type of relationship. In contrast to traditional content-only classification methods, relational learning succeeds in improving classification performance by leveraging the correlation of the labels …

Practical Issues In Gpram Development, Yin Li

Electronic Theses and Dissertations

In this thesis, two parts of practical issues in the GPRAM system design are included. The first part is the coding part. The sum-product decoding algorithm of LDPC codes has been refined to fit for the GPRAM hardware implementation. As we all know, communication channel has noise. The noise in telecom system is different from that in GPRAM systems. So the noise should be handled well in the GPRAM design. A noise look-up table was created for FPGA and those noises in the table are quantized. The second part of the thesis is to convert perfect images in video stream …

Learning To Grasp Unknown Objects Using Weighted Random Forest Algorithm From Selective Image And Point Cloud Feature, Md Shahriar Iqbal

Electronic Theses and Dissertations

This method demonstrates an approach to determine the best grasping location on an unknown object using Weighted Random Forest Algorithm. It used RGB-D value of an object as input to find a suitable rectangular grasping region as the output. To accomplish this task, it uses a subspace of most important features from a very high dimensional extensive feature space that contains both image and point cloud features. Usage of most important features in the grasping algorithm has enabled the system to be computationally very fast while preserving maximum information gain. In this approach, the Random Forest operates using optimum parameters …

Investigation Of Different Dielectric Materials As Gate Insulator For Mosfets, Ritika Oswal

Electronic Theses and Dissertations

The scaling of semiconductor transistors has led to a decrease in thickness of the silicon dioxide layer used as gate dielectric. The thickness of the silicon dioxide layer is reduced to increase the gate capacitance, thus increasing the drain current. If the thickness of the gate dielectric decreases below 2nm, the leakage current due to the tunneling increases drastically. Hence it is necessary to replace the gate dielectric, silicon dioxide, with a physically thicker oxide layer of high-k materials like Hafnium oxide and Titanium oxide. High-k dielectric materials allow the capacitance to increase without a huge leakage current. Hafnium oxide …

Constant-Stress Accelerated Life Test Of White Organic Light-Emitting Diode Based On Least Square Method Under Weibull Distribution, J Zhang, C Liu, G Cheng, X Chen, J Wu, Q Zhu, Laichang Zhang

Research outputs 2014 to 2021

It is currently hard to estimate the reliability parameters of organic light-emitting diodes (OLEDs) when conducting a life test at normal stress, due to the remarkably improved life of OLEDs to thousands hours. This work adopted three constant-stress accelerated life tests (CSALTs) to predict the life of white OLEDs in a short time. The Weibull function was applied to describe the life distribution, and the shape and scale parameters were estimated using the least square method. The experimental test data were statistically analyzed using a self-developed software. The life of white OLEDs predicted via this software is in good agreement …

Service And Communication Management In Cooperative Vehicular Networks, Olivia Brickley

Theses

The concept of Intelligent Transportation Systems (ITS) presents new R&D challenges for the transportation and ICT sectors and is currently receiving considerable interest from the research community. The primary objective of ITS is the creation of advanced road traffic systems for improved traffic safety, efficiency, and travelling comfort. Basic vehicle and roadside infrastructure collaboration allows for an increase in efficiency and safety and acts as the foundation for an extensive service set to achieve these ITS goals. Applications such as journey planning, automatic tolling and emergency warnings, among others, are envisaged in a system which can potentially reform modern transportation. …

A Novel Waveform For Emergency Services Mobile Ad-Hoc Networks : The Link Layer Perspective, Sebastian Helmle

Theses

Existing wireless communication systems of emergency services mainly enable ordinary unicast or broadcast voice communications. The increasing demand for data services such as messaging, file transfer, maps, etc requires those long-range communication systems to provide higher data rates while maintaining robustness against link failures. In this thesis, various aspects of a link layer design specifically for narrowband mobile ad-hoc networks (MANETs) that are targeted at emergency services are investigated.

The major aspect of this thesis is the optimisation of a time division multiple access (TDMA) design considering both efficient and reliable multicast resource reservation. An approach to mathematically describe a …

Wind Energy In Ireland - An Analysis Of Percentage Error In Forecasting, Michael Mcdonald

Dissertations

This research aimed to examine the percentage error in forecasting of wind energy using datasets from a small wind farm in Ireland. Furthermore, the study aimed to compare this calculated data to the national forecasting percentage errors. Internationally, the electrical sector and society are undergoing a revolution in terms of 'green economy'. This paradigm shift towards renewable energy technologies is recognised as a priority, with diminution of finite fossil fuels at its core. Renewable energy as a sector has provided significant financial stimulation to global economies in recent years. Moreover, wind energy has provided significant amounts of clean electricity throughout …

Quantum Efficiency Enhancement For Gan Based Light-Emitting Diodes And Vertical Cavity Surface-Emitting Lasers, Fan Zhang

Theses and Dissertations

This thesis explores the improvement of quantum efficiencies for InGaN/GaN heterostructures and their applications in light-emitting diodes (LEDs) and vertical cavity surface-emitting lasers (VCSELs). Different growth approaches and structural designs were investigated to identify and address the major factors limiting the efficiency. (1) Hot electron overflow and asymmetrical electron/hole injection were found to be the dominant reasons for efficiency degradation in nitride LEDs at high injection; (2) delta p-doped InGaN quantum barriers were employed to improve hole concentration inside the active region and therefore improve hole injection without sacrificing the layer quality; (3) InGaN active regions based on InGaN multiple …

Translation Of 'Seasons Of Life: A Panoramic Selection Of Songs By Rabindranath Tagore', Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

No abstract provided.

A New Algorithm For Piecewise Affine System Identification And Its Application To A Mems Switch, Niel Canty

Theses

Over the past ten years, hybrid systems, and piecewise affine (PWA) systems in particular have been viewed as viable option for modelling nonlinear systems. Many methods have been developed to cater for the identification of a PWA model from input/output data. This thesis focuses on the clustering based identification approach. This method uses a Least Squares (LS) identification algorithm which, in this thesis, is shown to perform poorly in practice. The clustering based algorithm is also limited by the number of initialisation parameters that need to be chosen. These parameters have a significant influence on the resulting PWA model accuracy, …

Location Management And Hybrid Geo-Routing For Urban Vehicular Networks, Aisling O'Driscoll

Theses

In recent years the motivation for comfort applications e.g. infotainment, file exchange and vehicle to vehicle (V2V) multiplayer gaming amongst others, has emerged as an active area of vehicular communications and network research. The success of such applications relies on the ability of a geo-routing protocol to deliver communication packets in a frequently disconnected communication environment. To do this, the location of the destination vehicle must first be determined and secondly, must reliably deliver the packet from source to destination. To determine the location of a target vehicle towards which packets can be forwarded, geo-routing algorithms utilise a location service …

Design And Analysis Of Reconfigurable Sensing Antennas For Wireless Sensing Applications, Qian Qiao

Electronic Theses and Dissertations

Reconfiguration sensing antenna (rsa) is a novel antenna concept, which not only can transmit or receive radio waves but also can sense the surrounding environment. The environment sensing is realized by reconfiguring the antenna's characteristics, such as resonant frequency, and radar cross section (rcs). The rsas possess the advantages of passive and low cost, which make them suitable for the large-scale wireless sensing networks (wsns) deployment. In this dissertation, the rsas concept is demonstrated, and two sensing mechanisms performed in the rsas are investigated. In order to verify these sensing mechanisms, four rsas are designed, analyzed, and measured. All the …

Treatment-Specific Approaches For Analysis And Control Of Left Ventricular Assist Devices, George Faragallah

Electronic Theses and Dissertations

A Left Ventricular Assist Device (LVAD) is a mechanical pump that helps patients with heart failure conditions. This rotary pump works in parallel to the ailing heart and provides an alternative path for blood flow from the weak left ventricle to the aorta. The LVAD is controlled by the power supplied to the pump motor. An increase in the pump motor power increases the pump speed and the pump flow. The LVAD is typically controlled at a fixed setting of pump power. This basically means that the controller does not react to any change in the activity level of the …

Growth And Analysis Of Micro And Nano Cdte Arrays For Solar Cell Applications, Brandon Adrian Aguirre

Open Access Theses & Dissertations

CdTe is an excellent material for infrared detectors and photovoltaic applications. The efficiency of CdTe/CdS solar cells has increased very rapidly in the last 3 years to ~20% but is still below the maximum theoretical value of 30%. Although the short-circuit current density is close to its maximum of 30 mA/cm2, the open circuit voltage has potential to be increased further to over 1 Volt. The main limitation that prevents further increase in the open-circuit voltage and therefore efficiency is the high defect density in the CdTe absorber layer. Reducing the defect density will increase the open-circuit voltage above 1 …

Optimized Integrated Software Package For Classification Of Small Airway Dysfunction Using Genetic Algorithms, Elias Estrada

Open Access Theses & Dissertations

Due to the similarity in the symptoms of respiratory disorders, an accurate diagnosis could be a difficult task. Regarding asthma as the main focus of this research, early detection of small airway impairment could represent a better opportunity for timely diagnosis. An integrated software package (ISP) based on the impulse oscillometry technique, has been developed to serve as an important tool for clinicians during classification of asthma severities on children [1]. The current version of the ISP was tested with data obtained during several years by Dr. Homer Nazeran and Dr. Michael Goldman from 110 Hispanic children [2], providing an …

Situational Assessment Of Multi Sensor Data, Eduardo Estrada

Open Access Theses & Dissertations

The importance of sensors has grown dramatically through the years, specially since they have the capability to create a specific task. Multiple sensor fusion is an area that has rapidly grown due to its multiple and beneficial applications. It is common to develop devices that have multiple sensors; however, the fusion of these multiple sensors to make a single output is remarkable. In fact, this is the way people chose to try to model the human body which has innumerable sensors and makes one decision. The development of sensor fusion not only helps create innovations in technology, but has the …

Design Of Three Different Particle Size Distributions In Silver Paste Through Computer Simulation For Higher Electrical Conductivity, Kyungdeok Jang

Open Access Theses & Dissertations

In the field of printed electronics technology, researchers have tried to print highly conductive electrodes with fine width and height in order to manufacture high performance devices.

The purpose of this research is to print particle monolayer silver patterns which have better electrical conductivity than existing ones. The key idea of this experiment is to analyze silver inks with different sized particles. Let us consider a particle monolayer pattern printed with silver ink consisting of mono-sized particles. Inside of the pattern, there are some vacant spaces between the particles, which can lead to low electrical conductivity and discontinuity of the …

Digitally Manufactured Spatially Variant Photonic Crystals, Javier Jair Pazos

Open Access Theses & Dissertations

Metamaterials and photonic crystals are engineered composites that exhibit electromagnetic properties superior to those found in nature. They have been shown to produce novel and useful phenomena that allow extraordinary control over the electromagnetic field. One of these phenomena is self-collimation, an effect observed in photonic crystals in which a beam of light propagates without diffraction and is forced to flow in the direction of the crystal. Self-collimation however, like many of the mechanisms enabled through dispersion engineering, is effective in directions only along the principal axes of the lattice. To this effect, a general purpose synThesis procedure was developed …

Frequency Selective Surfaces For Extreme Applications, Jay Houston Barton

Open Access Theses & Dissertations

It is known that for high-power microwaves and other extreme environments, the use of resonant metallic elements in frequency selective surfaces can be problematic. The solution developed within this Dissertation to solve these problems was to use guided-mode resonance phenomenon to create all-dielectric frequency selective surfaces that could survive these extreme environments.

To fully understand how these devices work, three different computational electromagnetic methods are formulated and implemented. The formulation of these methods start with the differential form of Maxwellâ??s equation and are derived all the way down to the final simulation state. This is done sequentially and all the …

3d Printed Spatially Variant Anisotropic Metamaterials, Cesar Roman Garcia

Open Access Theses & Dissertations

The recent advancement in 3D printing has created a new way to design electronics and electromagnetic devices. This allows for a new breed of non-planar designs to be used, fully exploiting all three dimensions like never before. More functions can be fit into the same amount of space, products with novel form factors can be more easily manufactured, interconnects can be routed more smoothly, interfaces can be better implemented, electrical and mechanical functions can be comingled, and entirely new device paradigms will be invented. When departing from traditional planar topologies many new problems arise like signal integrity, crosstalk, noise, and …

A Robust Algorithm For Estimating The Balance Of Autonomic Nervous System With Application To Mental Fatigue Detection Using Photoplethysmographic (Ppg) Signals, Ajay Kumar Verma

Open Access Theses & Dissertations

Spectral- and time-domain analysis of Heart Rate Variability (HRV) signal is widely used as a quantitative marker of the Autonomic Nervous System (ANS) activity. A robust algorithm was developed to derive HRV from photoplethysmographic (PPG) signals, to compute FFT- and AR-based spectra of these HRV signals, and to determine time- and frequency-domain features. This algorithm has detrending, sample-rate reductions, false-peak removal, automatic peak detection, peak-to-peak (P-P) interval detection and correction, time-domain feature extraction, HRV signal generation, and spectral-domain feature extraction from the HRV signal. Adapting to the very low spectral contents of the input PPG signal is very helpful in …

Harmonic Power Compensation Capacity Of Shunt Apf And Its Relationship To Design Parameters, Shafiuzzaman Khadem, Malabika Basu, Michael Conlon

Articles

VSI-based three-phase; power exchange mechanism; switching dynamics; three-phase systems; active losses; single-phase systems; power tetrahedron phasor diagram; shunt active power filter; harmonic power compensation capacity; four-wire systems; hysteresis band current control