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Full-Text Articles in Engineering

Modeling And Control Of Magnetic Gear Dynamics In A Wind Turbine Drivetrain, Danielle Vournas Sep 2019

Modeling And Control Of Magnetic Gear Dynamics In A Wind Turbine Drivetrain, Danielle Vournas

Dissertations and Theses

This thesis looks at the modeling and simulation of linear and nonlinear magnetic gear dynamics in a wind turbine drivetrain. The objective is to lay the groundwork for analysis, modeling and optimization of control structures focused on pole-slip prevention. A classical mechanical two-mass torsion spring model is used as the basis for developing the dynamic system equations and Simulink models. The wind turbine torque input to the low speed rotor is modeled as a disturbance input, the generator torque is modeled as a controlled input, and the high-speed rotor speed is the only measured output. The nonlinear dynamics are linearized ...


Sensory Relevance Models, Walt Woods Aug 2019

Sensory Relevance Models, Walt Woods

Dissertations and Theses

This dissertation concerns methods for improving the reliability and quality of explanations for decisions based on Neural Networks (NNs). NNs are increasingly part of state-of-the-art solutions for a broad range of fields, including biomedical, logistics, user-recommendation engines, defense, and self-driving vehicles. While NNs form the backbone of these solutions, they are often viewed as "black box" solutions, meaning the only output offered is a final decision, with no insight into how or why that particular decision was made. For high-stakes fields, such as biomedical, where lives are at risk, it is often more important to be able to explain a ...


Drafting In Self-Timed Circuits, Christopher Lee Cowan Aug 2019

Drafting In Self-Timed Circuits, Christopher Lee Cowan

Dissertations and Theses

Intervals between data items propagating in self-timed circuits are controlled by handshake signals rather than by a clock. In many self-timed designs, a trailing data item will catch up with a leading item or token, even when it trails by thousands of gate delays. This effect, called "drafting," can be seen in many of the self-timed designs, e.g., GasP, Mousetrap, Click, and Micropipeline. The purpose of this dissertation is to reveal the circuit mechanism of drafting in self-timed circuits typically used in FIFO stages. Drafting is usually considered to be incidental to the operation of self-timed circuits since interval ...


Large-Scale Der Aggregations Of Electric Water Heaters And Battery Inverter Systems, Kevin Marnell Jul 2019

Large-Scale Der Aggregations Of Electric Water Heaters And Battery Inverter Systems, Kevin Marnell

Dissertations and Theses

Distributed energy resources like residential electric water heaters and residential battery inverter systems offer a small amount of change to the grid individually. When aggregated however, these assets can cause major effects to the electric grid. Aggregating these resources allows them to take on generator-like functions with the ability to increment power and decrement power.

The Western Energy Imbalance Market is an energy market offering 15 minute and 5 minute markets for energy transactions between balancing areas. Generation assets make increment and decrement bids. Traditionally the only entrants to this market have been large scale generators and large scale assets ...


A Resource Constrained Shortest Paths Approach To Reducing Personal Pollution Exposure, Elling Payne Jun 2019

A Resource Constrained Shortest Paths Approach To Reducing Personal Pollution Exposure, Elling Payne

REU Final Reports

As wildfires surge in frequency and impact in the Pacific Northwest, in tandem with increasingly traffic-choked roads, personal exposure to harmful airborne pollutants is a rising concern. Particularly at risk are school-age children, especially those living in disadvantaged communities near major motorways and industrial centers. Many of these children must walk to school, and the choice of route can effect exposure. Route-planning applications and frameworks utilizing computational shortest paths methods have been proposed which consider personal exposure with reasonable success, but few have focused on pollution exposure, and all have been limited in scalability or geographic scope. This paper addresses ...


Analyzing Disparities In Ecosystem Services In U.S. Cities: The Relationship Between Tree Cover And Socio-Demographics, Katherine V. Cendrowski Jun 2019

Analyzing Disparities In Ecosystem Services In U.S. Cities: The Relationship Between Tree Cover And Socio-Demographics, Katherine V. Cendrowski

REU Final Reports

It is a generally accepted fact that trees, and vegetation in general, provide many benefits to human beings. What has not been so extensively studied is how those benefits may be distributed across the United States. This research project aims to study that distribution by modeling and analyzing the land use data of US cities and the socio-demographic data available. We are looking specifically at tree cover as presented in the National Land Cover Dataset (NLCD) in order to determine what the general demographics are of those people that live in closer proximity to trees. We are also looking at ...


Aggregation Of Electric Water Heaters For Peak Shifting And Frequency Response Services, Thomas Leighton Clarke Jun 2019

Aggregation Of Electric Water Heaters For Peak Shifting And Frequency Response Services, Thomas Leighton Clarke

Dissertations and Theses

The increased penetration of renewable energy sources poses new challenges for grid stability. The stochastic and uncontrollable generation of solar and wind power cannot be adjusted to match the load profile, and the transition away from traditional synchronous generators is reducing the grid capacity to arrest and recover from frequency disturbances.

Additionally, the distributed nature of many renewable energy sources makes centralized control of generation more complicated. The traditional power system paradigm balances the supply and demand of electricity on the grid by regulating generation. As this becomes more difficult, one alternative is to adjust the load instead. This is ...


Uhf And Microwave Phase-Modulated Scattering Array, Nasr Nomas Hussein Alkhafaji Jun 2019

Uhf And Microwave Phase-Modulated Scattering Array, Nasr Nomas Hussein Alkhafaji

Dissertations and Theses

This dissertation investigates the use an array of active nonlinear elements, with particular emphasis on controlling distortion products generated by nonlinear elements in space rather than using conventional ways such as transmission lines, waveguides, and power dividers and combiners. The nonlinear elements are made of assemblies of antennas and electronic switches, called modulated scatterers (MSs). These so-called MSs elements are utilized in a wide variety of applications such as radio frequency identification (RFID) systems, microwave imaging, Internet-of-Things sensors, etc. However, no research work has been reported in the literature regarding exploiting and controlling several distortion products generated by MSs at ...


Electromagnetic Analysis Of A Wind Turbine Magnetic Gearbox, Kang Li, Sina Modaresahmadi, Wesley B. Williams, Jonathan Bird Jun 2019

Electromagnetic Analysis Of A Wind Turbine Magnetic Gearbox, Kang Li, Sina Modaresahmadi, Wesley B. Williams, Jonathan Bird

Electrical and Computer Engineering Faculty Publications and Presentations

The design of the second stage of a 59:1 multi-stage magnetic gearbox for a wind turbine demonstrator is presented. The multi-stage series-connected magnetic gearbox is composed of a 6.45 first stage and 9.14 second stage. A flux-focusing spoke-type rotor typology is used with a unique segmented fully laminated design. The impact of structural design changes is considered with respect to torque density. A new rotor typology is presented that enables the magnetic gearbox to be mechanically assembled first without magnets.


Evaluation Of Bus-Bicycle And Bus/Right-Turn Traffic Delays And Conflicts, Katherine L. Keeling, Travis B. Glick, Miles Crumley, Miguel A. Figliozzi Jun 2019

Evaluation Of Bus-Bicycle And Bus/Right-Turn Traffic Delays And Conflicts, Katherine L. Keeling, Travis B. Glick, Miles Crumley, Miguel A. Figliozzi

Electrical and Computer Engineering Faculty Publications and Presentations

This research evaluates conflicts and delays caused by interactions among buses, bicycles, and right-turning vehicles at a mixed traffic corridor in Portland, OR. The study site has a near-side bus stop and a right curbside lane designated for buses and right-turning vehicles. Next to the bus/right-turn lane is a bicycle lane with a bicycle box ahead of the bus stop (i.e., between the intersection and the bus stop). This research examines two concerns caused by these overlapping bus, bicycle, and automobile facilities; the first is the number of bus-bicycle conflicts (as a proxy for safety) and the second ...


Very High Frequency Bipolar Junction Transistor Frequency Multiplier Drive Network Design And Analysis, Daniel Dale Schaeffer May 2019

Very High Frequency Bipolar Junction Transistor Frequency Multiplier Drive Network Design And Analysis, Daniel Dale Schaeffer

Dissertations and Theses

The function of a frequency multiplier is verbatim -- a frequency multiplier is a circuit that takes a signal of particular frequency at the input and produces harmonic multiples of the input signal's frequency at the output. Their use is widespread throughout history, primarily in the application of frequency synthesis. When implemented as a part of a large system, a chain of multipliers can be used to synthesize multiple reference signals from a single high-performance reference oscillator.

Frequency multiplier designs use a variety of nonlinear devices and topologies to achieve excitation of harmonics. This thesis will focus on the design ...


An Assessment Of The Decision Making Units’ Efficiency In Service Systems (The Case Of Cellular Telecom), Maoloud Dabab, Timothy R. Anderson May 2019

An Assessment Of The Decision Making Units’ Efficiency In Service Systems (The Case Of Cellular Telecom), Maoloud Dabab, Timothy R. Anderson

Student Research Symposium

Most tools and models on performance and quality of service management are generic and do not solve the complex technical systems, which the most critical component on the network and where these tools should be applied. The objective of this research is to assess the cellular performance and Base Transceiver Station (BTS) efficiency by proposing a robust model that is derived from multiple Key Performance Indicators (KPIs) based on technical and financial aspects. The novelty of this research provides a comprehensive multidimensional model for tuning the BTS parameters, which can lead to developing a standard global mobile network KPI. The ...


Explanation Methods For Neural Networks, Jack H. Chen, Christof Teuscher May 2019

Explanation Methods For Neural Networks, Jack H. Chen, Christof Teuscher

Student Research Symposium

Neural Networks (NNs) have become a basis of almost all state-of-the-art machine learning algorithms and classifiers. While NNs have been shown to generalize well to real-world examples, researchers have struggled to show why they work on an intuitive level. We designed several methods to explain the decisions of two state-of-the-art NN classifiers, ResNet and an All-CNN, in the context of the Japanese Society of Radiological Technology (JSRT) lung nodule dataset and the CIFAR-10 image dataset. Leading explanation methods LIME and Grad-CAM generate variations of heat maps which represent the regions of the input determined salient by the NN. We analyze ...


Reliable Explanations Via Adversarial Examples On Robust Networks, Walt Woods, Jack H. Chen, Christof Teuscher May 2019

Reliable Explanations Via Adversarial Examples On Robust Networks, Walt Woods, Jack H. Chen, Christof Teuscher

Student Research Symposium

Neural Networks (NNs) are increasingly used as the basis of advanced machine learning techniques in sensitive fields such as autonomous vehicles and medical imaging. However, NNs have been found vulnerable to a class of imperceptible attacks, called adversarial examples, which arbitrarily alter the output of the network. To close the schism between needing reliability in real-world applications and the fragility of NNs, we propose a new method for stabilizing networks, and show that as an added bonus, our technique results in reliable, high-fidelity explanations for the NN's decision. Compared to the state-of-the-art, this technique increased the area under the ...


Design And Performance Evaluation Of Linear And Axial-Flux Magnetic Gears, Mojtaba Bahrami Kouhshahi Apr 2019

Design And Performance Evaluation Of Linear And Axial-Flux Magnetic Gears, Mojtaba Bahrami Kouhshahi

Dissertations and Theses

The conversion from low speed to high speed and vice versa in various forms, including rotary and linear motion, is a requirement for a wide range of applications. For example, wind power generation requires a conversion of low speed rotation of turbine blades to high speed generator rotation, and ocean wave power generation is achievable by conversion of low speed linear motion to either high speed rotation or high speed linear motion. Mechanical gearboxes, hydraulic and pneumatic actuators are commonly used to achieve these conversions. However, these systems suffer from reliability issues, high maintenance requirements, noise, and lack of overload ...


Investigation Of Electronic And Optical Properties Of 2-Dimensional Semiconductor Tin Selenide (Snse) Thin Films, Shakila Afrin Mar 2019

Investigation Of Electronic And Optical Properties Of 2-Dimensional Semiconductor Tin Selenide (Snse) Thin Films, Shakila Afrin

Dissertations and Theses

Over the last 5 decades, the semiconductor industry has been well served by Si based technology due to its abundant availability, lower manufacturing cost, large wafer sizes and less complexity in fabrication. Over this period, electronic devices and integrated systems have been miniaturized by downscaling of the transistors. The miniaturization has been guided by the Moore's law where the numbers of transistors have doubled over every two years. However, the trend of transistor miniaturization is fast approaching its limit. Hence, alternate and innovative solutions are necessary to tackle this problem and this propels the research for finding novel materials ...


Efficient Methods For Robust Circuit Design And Performance Optimization For Carbon Nanotube Field Effect Transistors, Muhammad Ali Mar 2019

Efficient Methods For Robust Circuit Design And Performance Optimization For Carbon Nanotube Field Effect Transistors, Muhammad Ali

Dissertations and Theses

Carbon nanotube field-effect transistors (CNFETs) are considered to be promising candidate beyond the conventional CMOSFET due to their higher current drive capability, ballistic transport, lesser power delay product and higher thermal stability. CNFETs show great potential to build digital systems on advanced technology nodes with big benefits in terms of power, performance and area (PPA). Hence, there is a great need to develop proven models and CAD tools for performance evaluation of CNFET-based circuits. CNFETs specific parameters, such as number of tubes, pitch (spacing between the tubes) and diameter of CNTs determine current driving capability, speed, power consumption and area ...


Challenges In Designing A Mentorship Program For Electrical Engineering Freshmen, Branimir Pejcinovic, Melinda Holtzman Mar 2019

Challenges In Designing A Mentorship Program For Electrical Engineering Freshmen, Branimir Pejcinovic, Melinda Holtzman

Electrical and Computer Engineering Faculty Publications and Presentations

This Work in Progress Innovative Practice Paper addresses three challenges we face when teaching freshmen: a) how to present a wide variety of sub-fields in electrical engineering, b) how to establish the relevance of electrical engineering to things they care about, and c) how to relate electrical engineering to students' experiences. We are attempting to address these through a mentorship program involving recent alumni working with teams of freshman electrical engineering students. Mentors are expected to: (i) come to class and speak about their job experience, (ii) meet with their teams early in the term to help them get started ...


Spectral Clustering For Electrical Phase Identification Using Advanced Metering Infrastructure Voltage Time Series, Logan Blakely Jan 2019

Spectral Clustering For Electrical Phase Identification Using Advanced Metering Infrastructure Voltage Time Series, Logan Blakely

Dissertations and Theses

The increasing demand for and prevalence of distributed energy resources (DER) such as solar power, electric vehicles, and energy storage, present a unique set of challenges for integration into a legacy power grid, and accurate models of the low-voltage distribution systems are critical for accurate simulations of DER. Accurate labeling of the phase connections for each customer in a utility model is one area of grid topology that is known to have errors and has implications for the safety, efficiency, and hosting capacity of a distribution system. This research presents a methodology for the phase identification of customers solely using ...


Application Of Improved Feature Selection Algorithm In Svm Based Market Trend Prediction Model, Qi Li Jan 2019

Application Of Improved Feature Selection Algorithm In Svm Based Market Trend Prediction Model, Qi Li

Dissertations and Theses

In this study, a Prediction Accuracy Based Hill Climbing Feature Selection Algorithm (AHCFS) is created and compared with an Error Rate Based Sequential Feature Selection Algorithm (ERFS) which is an existing Matlab algorithm. The goal of the study is to create a new piece of an algorithm that has potential to outperform the existing Matlab sequential feature selection algorithm in predicting the movement of S&P 500 (^GSPC) prices under certain circumstances. The two algorithms are tested based on historical data of ^GSPC, and Support Vector Machine (SVM) is employed by both as the classifier. A prediction without feature selection ...


A High Torque Density Halbach Rotor Coaxial Magnetic Gear, Ho Yin Wong, Jonathan Z. Bird, David Barnett, Wesley Williams Jan 2019

A High Torque Density Halbach Rotor Coaxial Magnetic Gear, Ho Yin Wong, Jonathan Z. Bird, David Barnett, Wesley Williams

Electrical and Computer Engineering Faculty Publications and Presentations

This paper presents the design, analysis, and experimental testing results for a 5.67:1 Halbach rotor magnetic gearbox with a ferromagnetic back support. Using 3-D finite element analysis software the Halbach magnetic gearbox was calculated to achieve a volumetric torque density of 284N·m/L with only an active region outer diameter of 120mm. The experimental prototype obtained an active region volumetric torque density of 261.4N·m/L


Using Homing, Synchronizing And Distinguishing Input Sequences For The Analysis Of Reversible Finite State Machines, Martin Lukac, Michitaka Kameyama, Marek A. Perkowski, Pawel Kerntopf Jan 2019

Using Homing, Synchronizing And Distinguishing Input Sequences For The Analysis Of Reversible Finite State Machines, Martin Lukac, Michitaka Kameyama, Marek A. Perkowski, Pawel Kerntopf

Electrical and Computer Engineering Faculty Publications and Presentations

A digital device is called reversible if it realizes a reversible mapping, i.e., the one for which there exist a unique inverse. The field of reversible computing is devoted to studying all aspects of using and designing reversible devices. During last 15 years this field has been developing very intensively due to its applications in quantum computing, nanotechnology and reducing power consumption of digital devices. We present an analysis of the Reversible Finite State Machines (RFSM) with respect to three well known sequences used in the testability analysis of the classical Finite State Machines (FSM). The homing, distinguishing and ...


Machine-Learning Based Three-Qubit Gate For Realization Of A Toffoli Gate With Cqed-Based Transmon Systems, Sahar Daraeizadeh, Shavindra Premaratne, Xiaoyu Song, Marek A. Perkowski, Anne Y. Matsuura Jan 2019

Machine-Learning Based Three-Qubit Gate For Realization Of A Toffoli Gate With Cqed-Based Transmon Systems, Sahar Daraeizadeh, Shavindra Premaratne, Xiaoyu Song, Marek A. Perkowski, Anne Y. Matsuura

Electrical and Computer Engineering Faculty Publications and Presentations

We use machine learning techniques to design a 50 ns three-qubit flux-tunable controlled-controlled-phase gate with fidelity of >99.99% for nearest-neighbor coupled transmons in circuit quantum electrodynamics architectures. We explain our gate design procedure where we enforce realistic constraints, and analyze the new gate’s robustness under decoherence, distortion, and random noise. Our controlled-controlled phase gate in combination with two single-qubit gates realizes a Toffoli gate which is widely used in quantum circuits, logic synthesis, quantum error correction, and quantum games.