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Articles 91 - 120 of 656

Full-Text Articles in Electrical and Computer Engineering

Distributed Optimal Policies For Multi-Agent Systems Under Uncertainties, Mushuang Liu May 2020

Distributed Optimal Policies For Multi-Agent Systems Under Uncertainties, Mushuang Liu

Electrical Engineering Dissertations - Archive

Multi-agent systems (MAS) have attracted increasing attention in the past years due to their wide applications in mobile robots, sensor networks, autonomous driving systems, etc. Along with this trend, developing distributed optimal policies for MAS under uncertainties has become indispensable. Multi-dimensional uncertainties often modulate system dynamics in a complicated fashion, which leads to computational challenges for real-time control. In many practical MAS, each agent also has its own interest to optimize beyond a global objective. Developing distributed optimal control for agents with self-interests is needed. To address the above challenges, this dissertation contributes in two major directions for MAS: 1) …

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The Development Of On-Chip Optofluidic Droplet Lasers, Han Zhang May 2020

The Development Of On-Chip Optofluidic Droplet Lasers, Han Zhang

Electrical Engineering Dissertations - Archive

Optofluidic lasers have been an emerging field for the applications of biological sensing and diagnosis, chemical sensing, and point-of-care devices. Droplets, as optical cavities, confines whispering gallery modes with high quality factors in small volumes. Optofluidic droplet lasers have brought the droplet-based microfluidics and droplets as micro-resonators to one platform, showing potentials on applications in highly sensitive bio/chemical detection, tunable lasers, cell tracking and tissue imaging. Until now, optofluidic droplet lasers can be categorized into two types, static droplet lasers and droplet lasers on the flow. Static droplet lasers offer long lifetime for biosensing, while droplet lasers on the flow …

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Kernels And Beyond For Data Similarity Learning In Data Mining, Akshay Malhotra Dec 2019

Kernels And Beyond For Data Similarity Learning In Data Mining, Akshay Malhotra

Electrical Engineering Dissertations - Archive

This work discusses the problem of unsupervised clustering of signals/data vectors based on their information content. A correlation based perspective to the clustering problem has been considered, thus relying on the high correlation between data vectors from the same class rather than on the position of the vectors in the data space. In the past, correlation based clustering has been formulated using a canonical correlation framework or as a matrix factorization problem and has been solved with different variants of gradient descent. This work focuses on improving the clustering performance by modifying the framework to utilize non-linear associations or correlations. …

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Identification And Characterization Of Gate Oxide Defects Responsible For Low Frequency Noise In Mosfets, A. S. M. Shamsur Rouf Dec 2019

Identification And Characterization Of Gate Oxide Defects Responsible For Low Frequency Noise In Mosfets, A. S. M. Shamsur Rouf

Electrical Engineering Dissertations - Archive

The main objective of this work is to identify and characterize gate oxide defects that are present in submicron p-channel metal oxide semiconductor field effect transistors (pMOSFETs) and which are responsible for random telegraph signals (RTS). With the downscaling of MOSFETs, alternating capture and emission of channel carriers by defects residing at the oxide-semiconductor interface and bulk oxide have become a pronounced problem. Even though RTS has been used for several years as a tool to characterize the interface/bulk defects, RTS in pMOSFETs has been under-reported compared to that in nMOSFETs, resulting in less information on hole defects in pMOSFETs …

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Sub-Synchronous Resonance Analysis And Detection, Igor Brandao Machado Matsuo Dec 2019

Sub-Synchronous Resonance Analysis And Detection, Igor Brandao Machado Matsuo

Electrical Engineering Dissertations - Archive

With the increasing penetration of renewable generation resources, power grids have become more susceptible to sub-synchronous resonance phenomena, especially to sub-synchronous control interaction, which produces fast-growing oscillations. The power system operation requirements for a reliable, fast and accurate detection and monitoring system for protection and mitigation purposes are increasing. Besides, risk assessment analysis during grid planning and update studies can be extremely time-consuming due to a large number of possible grid configurations and small time-steps required for the simulation of detailed electromagnetic transient (EMT) models. The first part of this dissertation aims to provide an optimized tool for SSR risk …

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Flexible Ph Sensor For Smart Sensing, Khengdauliu Chawang Dec 2019

Flexible Ph Sensor For Smart Sensing, Khengdauliu Chawang

Electrical Engineering Theses - Archive

pH level of biofluid is crucial in understanding physiological health. Commercial glass electrode pH sensors are bulky and cannot provide real time data. In this study, a novel miniature pH sensor capable of continuous wireless communication was developed, which is a promising technology for providing point-of-care diagnosis. Iridium Oxide because of its wide pH sensing range and biocompatibility has attracted attention from biomedical and food industries; high sensitivity of Iridium Oxide based sensor is attributed to its high charge density. Flexible polyamide Kapton substrate (127 µm) is taken as base substrate and E-Beam method is employed to deposit adhesion and …

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Nonlinear Optics And Bio-Sensing With Silicon Nitride Waveguides, Subrata Das Dec 2019

Nonlinear Optics And Bio-Sensing With Silicon Nitride Waveguides, Subrata Das

Electrical Engineering Dissertations - Archive

Silicon Nitride (SiN) is a CMOS compatible optical material that can be used for both linear and nonlinear optics applications. SiN has high refractive index (1.99-2.0) and low two photon absorption (TPA) coefficient. As a result, SiN can be used as a core material to guide and bend light, and the development of compact on-chip SiN optical devices exploiting both linear and nonlinear optical phenomena is very much feasible. In this thesis work, two independent research projects are presented. The first work presents the design of a hybrid SiN/Polymer slot waveguide for second-harmonic generation (SHG) of a 1550-nm wave at …

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Design Of A Clc Testbed To Study High Voltage Capacitors, Christopher Francisco Martinez Dec 2019

Design Of A Clc Testbed To Study High Voltage Capacitors, Christopher Francisco Martinez

Electrical Engineering Theses - Archive

Pulsed power systems rely on the interconnection of several unique stages for successful implementation. These stages can include, but are not limited to a prime power source, power conditioning circuit, intermediate energy storage, pulsed forming network, and the load. There are many possible intermediate energy storage devices that can be considered, two of which are inductive and capacitive. There are many advantages and disadvantages that each offer. Inductive energy storage is several times more energy dense than capacitive energy storage but most of the time, an opening switch is required to transfer the energy to the load and those are …

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Flexible Electrochemical Sensors Based On Iridium Oxide For Biomedical Applications, Xuesong Yang Aug 2019

Flexible Electrochemical Sensors Based On Iridium Oxide For Biomedical Applications, Xuesong Yang

Electrical Engineering Dissertations - Archive

Considering the disadvantages of the costly, laborious, and time-consuming traditional clinical analyses, there is a tendency of developing non-hospital point-of-care which allows patients to monitor their health conditions conveniently at home. To optimize the convenience of the point-of-care instruments, a wearable device with the ability of detecting different biological components in different biological conditions is preferer. The device should also have the qualities of rapid analyses, high accuracy, and high sensitivity. To accomplish these requirements, we proposed a flexible electrochemical sensor based on iridium oxide (IrOx). As a noble metal, iridium oxide has the advantages of bio-compatible, stable, and corrosive …

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Affine Invariance In Multilayer Perceptron Training, Son Nam Nguyen Aug 2019

Affine Invariance In Multilayer Perceptron Training, Son Nam Nguyen

Electrical Engineering Dissertations - Archive

Training methods for both shallow and deep neural nets are dominated by first order algorithms related to back propagation and conjugate gradient. However, these methods lack affine invariance so performance is damaged by nonzero input means, dependent inputs, dependent hidden units and the use of only one learning factor. This dissertation reviews affine invariance and shows how MLP training can be made partially affine invariant when Newton's method is used to train small numbers of MLP parameters. Several novel methods are proposed for scalable partially affine invariant MLP training. The potential application of the algorithm to deep learning is discussed. …

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Long-Distance And Broad-Band Aerial Communication Using Directional Antennas: Theory, Implementation, And Applications, Songwei Li Aug 2019

Long-Distance And Broad-Band Aerial Communication Using Directional Antennas: Theory, Implementation, And Applications, Songwei Li

Electrical Engineering Dissertations - Archive

Unmanned aerial vehicles (UAV) have found broad civilian applications. However, existing commercial usages are limited to single UAVs. To facilitate commercial multi-UAV applications, robust UAV-to-UAV communication with long-distance and broad-band capabilities is critical. Such a communication architecture should not rely on ground infrastructure support, and hence can be applied whenever needed in scenarios where infrastructures are not available. It is foreseen to have extensive usages in a wide spectrum of commercial UAV applications such as emergency response, remote sensing, and nondestructive health monitoring. A promising solution for such a communication architecture is aerial communication using directional antennas (ACDA). We developed …

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Optimal Control Strategies And Reinforcement Learning For Dynamical Multiagent Systems In Graphical Games, Victor Gabriel Lopez Mejia Aug 2019

Optimal Control Strategies And Reinforcement Learning For Dynamical Multiagent Systems In Graphical Games, Victor Gabriel Lopez Mejia

Electrical Engineering Dissertations - Archive

As the number of autonomous agents increases in industrial and urban areas, the development of formal protocols to analyze their behavior as they interact with each other becomes of central interest in control systems research. Each agent in this setting is interested in completing a specific task with considerations of an optimal performance. Game theory has become one of the most useful tools in multiagent systems analysis due to its rigorous mathematical representation of optimal decision making. The analysis of dynamical systems has been developed in the branch of game theory regarded as differential games. The ser of graphical games …

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Towards Automated Understanding Of Laparoscopic Videos, Babak Namazi Aug 2019

Towards Automated Understanding Of Laparoscopic Videos, Babak Namazi

Electrical Engineering Dissertations - Archive

Despite the advantages of minimally invasive surgeries, the indirect access and lack of the 3D field of view of the area of interest introduce complications in the procedures. Fortunately, the recorded videos from the operation offer the opportunity for intra-operative and post-operative analyses of the procedures, to improve future performance and safety. Such analysis is essential to provide the tools for evaluation and assessment of the surgeries. In this dissertation, we investigate the potential of deep learning techniques in understanding the videos captured during laparoscopic surgeries. To this end, we describe new methods for identifying the surgical instruments and the …

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Electrochemical Energy Storage Integration Challenges Within High Voltage Distributed Generation Power System Architectures, Charles N. Nybeck May 2019

Electrochemical Energy Storage Integration Challenges Within High Voltage Distributed Generation Power System Architectures, Charles N. Nybeck

Electrical Engineering Dissertations - Archive

Future stationary and mobile microgrids may be deployed with a number of high power electrical loads that operate transiently. The transient nature of the loads will impart high stress on a microgrid’s power system, possibly pushing it outside of the acceptable power quality standards. To restore power quality and increase system reliability, it is being proposed that electrochemical energy storage systems be used as a buffer. Energy storage systems that store a great deal of energy and could be used with open circuit potentials (OCPs) as high as 1 kV. Since size and weight on a mobile microgrid is limited, …

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Wearable Biomedical Sensors, Wenyuan Shi May 2019

Wearable Biomedical Sensors, Wenyuan Shi

Electrical Engineering Dissertations - Archive

Focusing on current major research interests about the wearable biomedical sensors, numerous achievements contributed by researchers and engineers are reviewed in chapter 1. Development and research trends, as well as challenges of the wearable technologies are discussed. In chapter 2, a new double-resonance sensor was presented for monitoring body dehydration with two resonant frequencies. Using the waveguide method and the finite-element simulations, the sensor was designed with optimal parameters. Electromagnetic field distributions, Q factors, and sensitivities of the sensor are analyzed. The sensor’s equivalent circuit was deduced. The finite-element model and the equivalent circuit model were simulated for identifying various …

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Real-Time Multi-Pulse Rectifier Models For Power Hardware-In-The-Loop Implementation In Medium Voltage Dc Microgrid Applications, Brian J. Mcree May 2019

Real-Time Multi-Pulse Rectifier Models For Power Hardware-In-The-Loop Implementation In Medium Voltage Dc Microgrid Applications, Brian J. Mcree

Electrical Engineering Dissertations - Archive

Microgrids have proliferated the landscape of the world’s power systems as distributed energy generation, energy storage, and evolving electrical loads become more abundant. Microgrids offer many advantages to the end user of electrical power over traditional power distribution networks that rely on exceedingly large rotating machines producing power for a large group of electrical loads over long physical distances. Microgrids provide a unique benefit to smaller electrical networks that may be isolated, may have unique electrical loads, or may have a network of energy storage devices that can be utilized to serve the microgrid in particular operational scenarios. With the …

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Mems Wideband Energy Harvesting Using Nonlinear Springs And Mechanical Stoppers, Shaikh Md Rubayiat Tousif May 2019

Mems Wideband Energy Harvesting Using Nonlinear Springs And Mechanical Stoppers, Shaikh Md Rubayiat Tousif

Electrical Engineering Dissertations - Archive

Vibrational energy harvesters convert kinetic energy from environment to useful electrical energy to power wireless sensor networks. These devices are finding applications in robotics, defense, medical, structural health monitoring, aerospace and wearables. The goal of this dissertation is to improve the design of vibrational electrostatic energy harvesters. Wideband, out-of-plane gap-closing, electret-based electrostatic energy harvesters using nonlinear springs and mechanical stoppers are designed. A unique mechanism is developed to introduce nonlinearity in the force-displacement relationship by varying the spring anchor height relative to the level of the proof-mass in the vertical direction. Both spring softening and hardening responses are achieved. A …

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Design, Evaluation, And Modeling Of Medium Voltage Dc Energy Conversion Testbed With Emphasis On Electrochemical Energy Storage, David Alan Dodson May 2019

Design, Evaluation, And Modeling Of Medium Voltage Dc Energy Conversion Testbed With Emphasis On Electrochemical Energy Storage, David Alan Dodson

Electrical Engineering Dissertations - Archive

Much work has been done in recent years regarding the emphasis and newfound importance of energy storage and energy conversion within systems that, at one time, functioned off of simple alternating current (AC) busses. With the advancement in technology has come unique and demanding electrical loads and equipment, creating a need for many different electrical topologies and requirements. The scope of the work done here is related to current efforts and interests in islanded microgrid power systems. Microgrid electrical systems are evolving and new, demanding electrical systems are being invented and introduced. For example, advancements in communication and sensor systems …

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Uav: Trajectory Generation And Simulation, Neha Bhushan May 2019

Uav: Trajectory Generation And Simulation, Neha Bhushan

Electrical Engineering Theses - Archive

Unmanned Aerial Vehicles (UAVs) have gained mass popularity in fields such as Defense, Agriculture, Sport and Photography etc. Their wide adoption in such research projects have opened new horizons for opportunities. However, UAVs operate in a rather dynamic environment since various factors such as airspeed, temperature, pressure, turbulence etc. are capable of hampering the flight operation. There is a need for rather robust trajectory generation algorithm and system such that it provides an easy user interface to specify the path of UAV through space, alongside making the UAV capable enough to maneuver itself from the initial to final position. This …

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On The Analysis Of On-Board Sensing And Off-Board Sensing Through Wireless Communication For Uav Path Planning In Wind Fields, Murilo Augsto Pinheiro May 2019

On The Analysis Of On-Board Sensing And Off-Board Sensing Through Wireless Communication For Uav Path Planning In Wind Fields, Murilo Augsto Pinheiro

Electrical Engineering Theses - Archive

This work focuses on the roles of on-board sensing and off-board sensing through wireless communication for UAV missions. Employing UAV path planning under spatiotemporal wind effect as a case study, this work implements a modeling framework composed by the vehicle dynamics, environmental effect and communication model that transmits wind field data. Based on the analysis of the minimum-time optimal UAV path planning solution under communication constraints and spatiotemporal wind impact, this work obtains quantitative insights into the effect of communication quality and information update configuration on the performance of path planning. This study finds that on-board sensing and off-board sensing …

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Design And Fabrication Of Germanium-Based Guided-Mode Resonance Infrared Reflectors And Gold-Based Nanocavity Plasmonic Arrays, Daniel John Carney May 2019

Design And Fabrication Of Germanium-Based Guided-Mode Resonance Infrared Reflectors And Gold-Based Nanocavity Plasmonic Arrays, Daniel John Carney

Electrical Engineering Dissertations - Archive

Design, fabrication, and measurement techniques for germanium-based guided-mode resonance infrared wideband reflectors and applications of guided-mode resonance devices for sensing and measurement applications are presented. Germanium is a versatile semiconductor with physical properties similar to silicon but optical properties that make it well suited for the infrared wavelengths. It has a high refractive index and negligible absorption in the mid to far infrared spectral region that can be used to create high field confinement necessary for wideband and high quality factor devices. Fabrication of germanium devices becomes straight-forward once the physical matters of germanium’s material bonding properties and surface chemistries …

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Self-Induced Back Action Actuated Nanopore Electrophoresis (Sane) Sensor For Molecular Detection And Analysis, Sai Santosh Sasank Peri May 2019

Self-Induced Back Action Actuated Nanopore Electrophoresis (Sane) Sensor For Molecular Detection And Analysis, Sai Santosh Sasank Peri

Electrical Engineering Dissertations - Archive

We fabricated a novel single molecule nanosensor by integrating a Solid-State Nanopore (SSNP) and a Double Nanohole (DNH) nanoaperture. The nanosensor employs Self-Induced Back-Action (SIBA) for optical trapping and enables SIBA-Actuated Nanopore Electrophoresis (SANE) for concurrent acquisition of bimodal optical and electrical signatures of molecular interactions. We demonstrated the potential utility of the SANE sensor by trapping and translocating 20 nm silica and gold nanoparticles. The electrical translocation time of the nanoparticles was extended by four orders of magnitude due to opposing electrical and optical forces acting on the nanoparticle, causing high frequency oscillations or bobbing in the electrical signal. …

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Integration And Validation Of Power Hardware-In-The-Loop Generator Models For Deployment In A Distributed Generation Source Testbed, Jacob Sanchez May 2019

Integration And Validation Of Power Hardware-In-The-Loop Generator Models For Deployment In A Distributed Generation Source Testbed, Jacob Sanchez

Electrical Engineering Dissertations - Archive

Hardware in the Loop (HIL) is an established technology that allows for rapid prototyping of controls and verification of how physical devices respond for valid simulated systems. This involves deploying a model of a system onto a Field Programmable Gate Array (FPGA) that can take in external inputs and outputs the state variables present in the system. An example of this could involve the control of the roll, pitch, and yaw of a plane. A simulated plane could output the current state variables of the plane to an external controller which will respond with control signals to the simulated system …

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Deep Learning Based Fast Mode Decision In Hevc Intra Prediction Using Region Wise Feature Classification, Shiba Prasad Kuanar Dec 2018

Deep Learning Based Fast Mode Decision In Hevc Intra Prediction Using Region Wise Feature Classification, Shiba Prasad Kuanar

Electrical Engineering Dissertations - Archive

The High Efficiency Video Coding (HEVC) standard has achieved best coding efficiency as compared to previous H.264/AVC standard. But the computational time of HEVC encoder has increased mainly because of the hierarchical quad-tree based structure, recursive search for finding the best coding units, and the exhaustive prediction search up-to 35 modes. These advances improve the coding efficiency, but result into a very high computational complexity. Furthermore selecting the optimal modes among all prediction modes are necessary for the subsequent rate distortion optimization process.Therefore we propose a convolutional neural network (CNN) based algorithm which learns the region wise image features and …

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Sub-Synchronous Control Interaction – Modeling And Detection, Farshid Salehi Dec 2018

Sub-Synchronous Control Interaction – Modeling And Detection, Farshid Salehi

Electrical Engineering Dissertations - Archive

Power systems have recently become more susceptible to Sub-Synchronous Control Interaction (SSCI) due to the increasing penetration of renewable generation resources and series compensated lines. Any contingency which results in a radial condition between renewable generation resources and near-by series compensated lines might trigger an undamped SSCI oscillation. This is a purely electrical phenomenon which has potential to grow rapidly. Undamped SSCI oscillation can cause serious damage to the renewable generation resources and transmission elements and consequently leads to cascading outages. Due to the importance of the phenomena and its potential impacts, this research has focused on two aspects of …

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A Cmos Switched Capacitor Filter Based Potentiometric Readout Circuit For Chemfet Sensor, Revathy Perumalsamy Dec 2018

A Cmos Switched Capacitor Filter Based Potentiometric Readout Circuit For Chemfet Sensor, Revathy Perumalsamy

Electrical Engineering Theses - Archive

There are wide ranges of potentiometric sensors available for chemical sensing. The latest implementation of these sensors is CHEM resistors. In real time environment for an in-vivo application area, noise and power are the important factors. Though the selectivity of CHEM resistors improved with recent technological developments analog front end measurement circuits are always the limiting factor. Without compromising the performance parameters like gain and op-swing it is a challenge to improve the noise and power. Noise and power are the two factors which always require improvement. Also, there is trade-off between noise and power which needs to be balanced. …

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Accelerated Aging Of A Switching Power Supply Prototype, Michael J. Hibbard Dec 2018

Accelerated Aging Of A Switching Power Supply Prototype, Michael J. Hibbard

Electrical Engineering Theses - Archive

The LVPS (Low Voltage Power Supply) is a switching power supply custom designed for the ATLAS Tile Calorimeter at the Large Hadron Collider in Geneva Switzerland. Over one thousand of these LVPS, also called ’bricks’, will be produced for an upgrade cycle of all the detector electronics of the experiment. The responsibility of the technical design and manufacturing of these LVPS bricks has been supported by Dr. Hadavand’s ATLAS group at UT Arlington. As part of supporting the manufacturing process, a test station has been designed and prototyped to accelerate the aging of these brick past their infancy period. The …

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Lifepo4 Batteries: Impact Of Highly Parallel Packs On Load Distribution And Cycle Life, Caroline Storm Westenhover Aug 2018

Lifepo4 Batteries: Impact Of Highly Parallel Packs On Load Distribution And Cycle Life, Caroline Storm Westenhover

Electrical Engineering Dissertations - Archive

The United States Navy is considering Li-ion batteries for use as a primary power source for future naval shipboard pulsed-power applications. To supply sufficient power to a load, electrochemical cells are connected in series and parallel to create a higher voltage and higher capacity battery. The simplest way of connecting multiple cells in parallel is to tie all positive terminals together, all negative terminals together, and then electrically treat the array of cells as a single cell within the larger battery. In this configuration, a single battery management system (BMS) can be used to manage N parallel cells but there …

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Bio-Inspired Adaptive Tuning Of Human-Robot Interfaces, Bakur Alqaudi Aug 2018

Bio-Inspired Adaptive Tuning Of Human-Robot Interfaces, Bakur Alqaudi

Electrical Engineering Dissertations - Archive

Motivated by recent advancement in neurocognitive in brain modeling research, multiple model-based Q-learning structures are proposed for optimal tracking problem of time-varying discrete-time systems. This is achieved by utilizing a multiple-model scheme combined with adaptive resonance theory (ART), and dopamine-like model. In the ART algorithm , dopamine-like model and generates sub-models based on the match-based clustering method utilizing. A responsibility signal governs the likelihood of contribution of each sub-model to the Q-function. The Q-function is learned using the batch least-square algorithm. Simulation results are added to show the performance and the effectiveness of the overall proposed control method. A novel …

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Wireless Powered Flexible Gastrostimulator, Souvik Dubey May 2018

Wireless Powered Flexible Gastrostimulator, Souvik Dubey

Electrical Engineering Dissertations - Archive

Gastric electrical stimulation (GES) is an effective alternative to long-term dietary and medicinal treatment for gastroparesis. This work presents the design and development of two miniature implantable battery-less gastrostimulators, operated by wireless radio-frequency power. The devices deliver controlled electrical pulses to the stomach tissues to help regain normal motility. The first prototype was designed with the goal to optimize the wireless power transfer efficiency, various antenna configurations were investigated. The attenuation due to human tissue barrier was examined with an equivalent model. To enable reconfiguring the device to meet the patients' needs after implantation, a novel method of changing the …

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