Engineering Commons^™

Iot Development For Healthy Independent Living, Shalom Greene

Theses and Dissertations--Electrical and Computer Engineering

The rise of internet connected devices has enabled the home with a vast amount of enhancements to make life more convenient. These internet connected devices can be used to form a community of devices known as the internet of things (IoT). There is great value in IoT devices to promote healthy independent living for older adults.

Fall-related injuries has been one of the leading causes of death in older adults. For example, every year more than a third of people over 65 in the U.S. experience a fall, of which up to 30 percent result in moderate to severe injury. …

Contributions To Edge Computing, Vernon K. Bumgardner

Theses and Dissertations--Computer Science

Efforts related to Internet of Things (IoT), Cyber-Physical Systems (CPS), Machine to Machine (M2M) technologies, Industrial Internet, and Smart Cities aim to improve society through the coordination of distributed devices and analysis of resulting data. By the year 2020 there will be an estimated 50 billion network connected devices globally and 43 trillion gigabytes of electronic data. Current practices of moving data directly from end-devices to remote and potentially distant cloud computing services will not be sufficient to manage future device and data growth.

Edge Computing is the migration of computational functionality to sources of data generation. The importance of …

Fault Location In Transmission Systems Using Synchronized Measurements, Xiangqing Jiao

Theses and Dissertations--Electrical and Computer Engineering

Compared with conventional measurements from supervisory control and data acquisition (SCADA) system, phasor measurement units (PMUs) provide time-synchronized and direct measurements of phasors. The availability of synchronized phasor measurements can significantly improve power system protection and analysis. This dissertation is specifically committed to using synchronized measurements for estimation of fault locations in transmission systems.

Transmission lines are prone to various short-circuit faults. Accurate fault location is critical for rapid power recovery. Chapter 2 proposes a new fault location method based on sparse wide area measurements. One distinguishing feature of this method is its applicability to both transposed and untransposed transmission …

Real-Time Capture And Rendering Of Physical Scene With An Efficiently Calibrated Rgb-D Camera Network, Po-Chang Su

Theses and Dissertations--Electrical and Computer Engineering

From object tracking to 3D reconstruction, RGB-Depth (RGB-D) camera networks play an increasingly important role in many vision and graphics applications. With the recent explosive growth of Augmented Reality (AR) and Virtual Reality (VR) platforms, utilizing camera RGB-D camera networks to capture and render dynamic physical space can enhance immersive experiences for users. To maximize coverage and minimize costs, practical applications often use a small number of RGB-D cameras and sparsely place them around the environment for data capturing. While sparse color camera networks have been studied for decades, the problems of extrinsic calibration of and rendering with sparse RGB-D …

Experimental Investigation Of Reading Passive Uhf Tags In A Multi-Tag Environment, Yi Zhou

Theses and Dissertations--Mechanical Engineering

Recently, the Internet of things (IoT) has emerged as a promising solution for several industrial applications. One of the key components in IoT is passive radio frequency identification (RFID) tags which do not require a power source for operations. Specifically, ultra-high frequency (UHF) tags are studied in this paper. However, due to factors such as tag-to-tag interference and inaccurate localization, RFID tags that are closely spaced together are difficult to detect and program accurately with unique identifiers. This thesis investigates several factors that affect the ability to encode a specific tag with unique information in the presence of other tags, …

Autonomous Quadrotor Collision Avoidance And Destination Seeking In A Gps-Denied Environment, Thomas C. Kirven

Theses and Dissertations--Mechanical Engineering

This thesis presents a real-time autonomous guidance and control method for a quadrotor in a GPS-denied environment. The quadrotor autonomously seeks a destination while it avoids obstacles whose shape and position are initially unknown. We implement the obstacle avoidance and destination seeking methods using off-the-shelf sensors, including a vision-sensing camera. The vision-sensing camera detects the positions of points on the surface of obstacles. We use this obstacle position data and a potential-field method to generate velocity commands. We present a backstepping controller that uses the velocity commands to generate the quadrotor's control inputs. In indoor experiments, we demonstrate that the …

Hybrid Parallelization Of The Nasa Gemini Electromagnetic Modeling Tool, Buxton L. Johnson Sr.

Theses and Dissertations--Electrical and Computer Engineering

Understanding, predicting, and controlling electromagnetic field interactions on and between complex RF platforms requires high fidelity computational electromagnetic (CEM) simulation. The primary CEM tool within NASA is GEMINI, an integral equation based method-of-moments (MoM) code for frequency domain electromagnetic modeling. However, GEMINI is currently limited in the size and complexity of problems that can be effectively handled. To extend GEMINI’S CEM capabilities beyond those currently available, primary research is devoted to integrating the MFDlib library developed at the University of Kentucky with GEMINI for efficient filling, factorization, and solution of large electromagnetic problems formulated using integral equation methods. A secondary …

Novel Resource Efficient Circuit Designs For Rebooting Computing, Sai Subramanya Varun Thogarcheti

Theses and Dissertations--Electrical and Computer Engineering

CMOS based computing is reaching its limits. To take computation beyond Moores law (the number of transistors and hence processing power on a chip doubles every 18 months to 3 years) requires research explorations in (i) new materials, devices, and processes, (ii) new architectures and algorithms, (iii) new paradigm of logic bit representation. The focus is on fundamental new ways to compute under the umbrella of rebooting computing such as spintronics, quantum computing, adiabatic and reversible computing. Therefore, this thesis highlights explicitly Quantum computing and Adiabatic logic, two new computing paradigms that come under the umbrella of rebooting computing. Quantum …

Properties And Optimization Of Respiratory Navigator Gating For Spiral Cine Dense Cardiac Mri, Sean Michael Hamlet

Theses and Dissertations--Electrical and Computer Engineering

Cardiac magnetic resonance (MR) imaging can non-invasively assess heart function. Displacement encoding with stimulated echoes (DENSE) is an advanced cardiac MR imaging technique that measures tissue displacement and can be used to quantify cardiac mechanics (e.g. strain and torsion). When combined with clinical risk factors, cardiac mechanics have been shown to be better predictors of mortality than traditional measures of heart function.

End-expiratory breath-holds are typically used to minimize respiratory motion artifacts. Unfortunately, requiring subjects to breath-hold introduces limitations with the duration of image acquisition and quality of data acquired, especially in patients with limited ability to hold their breath. …

Target Read Operation Of Passive Ultra High Frequency Rfid Tag In A Multiple Tags Environment, Zi Qin Phua

Theses and Dissertations--Mechanical Engineering

Passive ultra-high frequency (UHF) radio frequency Identification (RFID) has emerged as a promising solution for many industrial applications. Passive UHF systems are relatively inexpensive to implement and monitor, as no line of sight is required for the communication. There are several advantages to using a passive RFID system. For example, no internal power source is required to activate the tags, and lower labor costs and efficient multitasking operations are expected in a long term scenario. However, due to factors such as tag-to-tag interference and inaccurate localization, RFID tags that are closely spaced together are difficult to detect and program accurately …

Advances In Multi-Agent Flocking: Continuous-Time And Discrete-Time Algorithms, Brandon Wellman

Theses and Dissertations--Mechanical Engineering

We present multi-agent control methods that address flocking in continuous-time and discrete-time settings. The method is decentralized, that is, each agents controller relies on local sensing to determine the relative positions and velocities of nearby agents. In the continuous-time setting, each agent has double-integrator dynamics. In the discrete-time setting, each agent has the discrete-time double-integrator dynamics obtained by sampling the continuous-time double integrator and applying a zero-order hold on the control input. We demonstrate using analysis, numerical simulations, and experimental demonstrations that agents using the flocking methods converge to flocking formations and follow the centralized leader (if applicable).

Real-Time Sensing And Control Of Developing Weld Penetration Through Reflection Vibration In Gtaw, Jinsong Chen

Theses and Dissertations--Electrical and Computer Engineering

GTAW (Gas Tungsten Arc Welding) weld pool surface is believed to contain sufficient information to determine the weld penetration, from which skilled welders are able to control the welding process to desired penetration states. However, it is unclear how human welders extract the weld penetration from the observed weld pool surface. In this research, a novel method is studied to determine the weld penetration based on the dynamic change of the weld pool surface.

This study observes/measures/analyzes the development of a weld pool from partial to full penetration and correlates such change to the weld penetration. Similar trends in the …

Time-Frequency Masking Performance For Improved Intelligibility With Microphone Arrays, Joshua P. Morgan

Theses and Dissertations--Electrical and Computer Engineering

Time-Frequency (TF) masking is an audio processing technique useful for isolating an audio source from interfering sources. TF masking has been applied and studied in monaural and binaural applications, but has only recently been applied to distributed microphone arrays. This work focuses on evaluating the TF masking technique's ability to isolate human speech and improve speech intelligibility in an immersive "cocktail party" environment. In particular, an upper-bound on TF masking performance is established and compared to the traditional delay-sum and general sidelobe canceler (GSC) beamformers. Additionally, the novel technique of combining the GSC with TF masking is investigated and its …

Exploration Of Majority Logic Based Designs For Arithmetic Circuits, Carson Labrado

Theses and Dissertations--Electrical and Computer Engineering

Since its inception, Moore's Law has been a reliable predictor of computational power. This steady increase in computational power has been due to the ability to fit increasing numbers of transistors in a single chip. A consequence of increasing the number of transistors is also increasing the power consumption. The physical properties of CMOS technologies will make this powerwall unavoidable and will result in severe restrictions to future progress and applications. A potential solution to the problem of rising power demands is to investigate alternative low power nanotechnologies for implementing logic circuits. The intrinsic properties of these emerging nanotechnologies result …

Improvements In Inverter Modeling And Control, Xiao Liu

Theses and Dissertations--Electrical and Computer Engineering

In this dissertation, the generalized averaging method models for inverters, reactive power control methods for photovoltaic inverters, and a noise immunity improvement for hybrid position observers for brushless dc motor drives are studied.

Models of inverters and other converters based on averaging have been widely used in numerous simulation applications. Generalized averaging can be applied to model both average and switching behavior of converters while retaining the faster run times associated with average-value models. Herein, generalized average models for single- and three-phase pulse width modulation inverters are proposed. The modulation signal for the proposed model could be either a sinusoidal …

Constant False Alarm Rate Performance Of Sound Source Detection With Time Delay Of Arrival Algorithm, Xipeng Wang

Theses and Dissertations--Electrical and Computer Engineering

Time Delay of Arrival (TDOA) based algorithms and Steered Response Power (SRP) based algorithms are two most commonly used methods for sound source detection and localization. SRP is more robust under high reverberation and multi-target conditions, while TDOA is less computationally intensive. This thesis introduces a modified TDOA algorithm, TDOA delay table search (TDOA-DTS), that has more stable performance than the original TDOA, and requires only 4% of the SRP computation load for a 3-dimensional space of a typical room. A 2-step adaptive thresholding procedure based on a Weibull noise peak distributions for the cross-correlations and a binomial distribution for …

Sparse Direct Solution Methods For Capacitive Extraction Problems On Closely-Spaced Geometries With High Aspect Ratios, Chee Kean Chang

Theses and Dissertations--Electrical and Computer Engineering

The method of moment (MoM) [1] is a widely used method in electromagnetics to solve static and dynamic electromagnetic problems on varying geometries. However, in closely spaced geometries coupled with large aspect ratios, e.g. a large parallel plate capacitor with very small separation gap, the problem exhibits several challenges. Firstly, the close proximity of the field and source elements presents problems with convergence in numerical evaluations of the interactions between them. Secondly, the aspect ratio of the geometry gives an approximation whereby to far field points, the source contributions from locations that are far apart appear to cancel each other. …

Analysis And Simulation Of Photovoltaic Systems Incorporating Battery Energy Storage, Oluwaseun M. Akeyo

Theses and Dissertations--Electrical and Computer Engineering

Solar energy is an abundant renewable source, which is expected to play an increasing role in the grid's future infrastructure for distributed generation. The research described in the thesis focuses on the analysis of integrating multi-megawatt photovoltaics (PV) systems with battery energy storage into the existing grid and on the theory supporting the electrical operation of components and systems. The PV system is divided into several sections, each having its own DC-DC converter for maximum power point tracking and a two-level grid connected inverter with different control strategies. The functions of the battery are explored by connecting it to the …