Electrical and Computer Engineering Commons^™

High-Performance Spectral Methods For Computer-Aided Design Of Integrated Circuits, Zhiqiang Zhao

Dissertations, Master's Theses and Master's Reports

Recent research shows that by leveraging the key spectral properties of eigenvalues and eigenvectors of graph Laplacians, more efficient algorithms can be developed for tackling many graph-related computing tasks. In this dissertation, spectral methods are utilized for achieving faster algorithms in the applications of very-large-scale integration (VLSI) computer-aided design (CAD)

First, a scalable algorithmic framework is proposed for effective-resistance preserving spectral reduction of large undirected graphs. The proposed method allows computing much smaller graphs while preserving the key spectral (structural) properties of the original graph. Our framework is built upon the following three key components: a spectrum-preserving node aggregation and …

A Progressive Output Strategy For Real-Time Feedback Control Systems, Qiming Zou, Ling Wang, Jie Liu, Yingtao Jiang

Electrical & Computer Engineering Faculty Research

The real-time requirements imposed on a feedback control system are often hard to be met, as the controller spends a disproportionately large amount of time waiting for a control cycle to reach its final state. When such a final state is established, multiple tasks have to be prioritized and launched altogether simultaneously, and the system is given an extremely short time window to generate its output. This huge gap between the wait and action times, perceived as a load unbalancing problem, hinders a control decision to be made in real time. To address this challenging problem, in this paper, we …

Dynamic Allocation/Reallocation Of Dark Cores In Many-Core Systems For Improved System Performance, Xingxing Huang, Xiaohang Wang, Yingtao Jiang, Amit Kumar Singh, Mei Yang

Electrical & Computer Engineering Faculty Research

A significant number of processing cores in any many-core systems nowadays and likely in the future have to be switched off or forced to be idle to become dark cores, in light of ever increasing power density and chip temperature. Although these dark cores cannot make direct contributions to the chip's throughput, they can still be allocated to applications currently running in the system for the sole purpose of heat dissipation enabled by the temperature gradient between the active and dark cores. However, allocating dark cores to applications tends to add extra waiting time to applications yet to be launched, …

Phase-Locked Loop Control In Low-Inertia Grid-Connected Voltage-Source Converters, Ifechukwude Gideon Odogwu

College of Graduate Studies: Theses & Dissertations

As the integration of renewable energy on the grid increases, the number of voltage-source converters (VSC) installed also does. VSC controls both switch turn-on and turn-off, allowing a dc voltage source to be switched between phases. For the converter to accurately synchronize with the grid, a phase-locked loop (PLL) is used for the frequency measurements of the grid. However, the implementation of PLL with measurement delay introduces harmonics, noise, high frequency, and voltage oscillation to the system due to its dynamics. The dynamics introduced to the grid can be ignored under stiff grid conditions, but power from renewable sources decreases …

Multi-Channel Anc System For Icu Patient Beds, Congzhi Bi

Graduate Research Theses & Dissertations

In an intensive care unit (ICU), there are many kinds of noises. For example, patients suffer from the noise which is made by doctors’ or nurses’ activities and devices of ICU can cause some problem too, like stress and losing ability of hearing. In this thesis, we propose to use active noise control (ANC) systems to reduce the high noise level for intensive care unit (ICU) residents.

At first, conventional multiple channel ANC system has been proposed to reduced noise. And then a new method has been proposed which is Auxiliary Filter Based Virtual Sensing (AF-VS) to compensate defect of …

Lane Detection Of Autonomous Vehicles Using Clustering And Augmented Sliding Windows Techniques, Keerti Chand Bhupathi

Graduate Research Theses & Dissertations

In this thesis, detection of solid lines and dashed lines of lanes using augmented sliding window technique, clustering technique and combination of both augmented sliding window and clustering is discussed. The lane points are extracted using image processing techniques. The performance of lane detection using these techniques is analyzed. Lanes are simulated in a laboratory for the input data set. The input data set consists of curved lines of dashed and solid lines which split and merge. Further, partially obscured lanes are also tested with the algorithm. The center of the lanes from vehicle to horizon is found based on …

Investigation Of The Impact Of Liquid Cooling On The Integrity Of Three-Dimensional Integrated Circuits (3d-Ics), A K M Toufiqul Islam

Graduate Research Theses & Dissertations

The thesis investigates the dynamics of liquid cooling of the Three-Dimensional Integrated Circuit (3D-IC). Using 3D ICs is one of the most viable solutions for achieving high integration density of integrated circuits, without facing the unavoidable problems arising from shrinking the device dimensions. However, 3D ICs suffer from other types of problems. One of these problems is the heat generation creating extremely hot areas called hot spots. For high hot spots, effective thermal management techniques need to be developed. Conventional thermal management of surface cooling of chips using heat sinks and fans may reduce the surface temperature, but the embedded …

Impact Of Grid-Following And Grid-Forming Ders On Resilient Operation Of Holonic Grid, Ali M. Alsenan

Electronic Theses and Dissertations

This thesis investigates how different distributed energy resources (DERs) impact the resilience operation of a holonic grid. The holonic grid consists of two or more connected microgrids and /or provisional microgrids (PMGs). The type of the DER, i.e., grid-forming or grid-following, affects the operations of the holonic grid, particularly during the islanded mode. To study this emerging and timely topic, a resilience-oriented holonic grid optimal operation model is proposed. This model carefully formulates the operations of both grid-forming and grid-following DERs. A variable value of lost load (VoLL) is further employed in the proposed model to help quantify and monetize …

Developing Machine Learning Algorithms For Behavior Recognition From Deep Brain Signals, Hosein Golshan Mojdehi

Electronic Theses and Dissertations

Parkinson’s disease (PD) is a neurodegenerative condition and movement disorder that appears with symptoms such as tremor, rigidity of muscles and slowness of movements. Deep brain stimulation (DBS) is an FDA-approved surgical therapy for essential tremor and PD. Despite the fact that DBS substantially alleviates the motor signs of PD, it can cause cognitive side effects and speech malfunction mainly due to the lack of adaptivity and optimality of the stimulation signal to the patients’ current state. A behavior-adapted closed-loop DBS system may reduce the side effects and power consumption by adjusting the stimulation parameters to patients’ need.

Behavior recognition …

Adaptive Object Detection For Autonomous Vehicles, Christopher Wolfe

Graduate Research Theses & Dissertations

Autonomous vehicles are gradually entering our daily lives. The goal of fully autonomous commercially available vehicles is becoming closer to reality each day as the contributions from researchers and various institutions are being added to the overall body of knowledge. Object detection is a critical component of an autonomous or semi-autonomous vehicle and draws extensively on results from many fields such as image processing and statistics. In this thesis, we consider ideas from the study of real-time computing and control systems to present a novel method of real-time adaptive object detection. We present a conceptual framework of the method as …

Partial Shading In Photovoltaic Cells Using Fuzzy Logic Tuned Particle Swarm Optimization Method Of Maximum Power Point Tracking Control, Nauman Moiz Mohammed Abdul

Graduate Research Theses & Dissertations

This paper dealt with the study of a newly modified fuzzy adaptive particle swarm

optimization controller and compared it with various existing conventional and advanced

controllers. A traditional PSO controller has the problems of oscillations and slow convergence. It is modified using fuzzy logic to decrease the number of oscillations and optimize

the convergence speed to produce a better efficient output. This controller is built to adapt

under various solar irradiances and partial solar conditions on the solar panels. This controller is then tested along with other various controllers, results recorded and studied. The

simulations are performed on the MatLab …

A Multi-Constraint Predictive Control System With Auxiliary Emergency Controllerfor Autonomous Vehicles, Farhad Partovi Ebrahimpour

Graduate Research Theses & Dissertations

In the last few years, several research groups and companies have worked on developing autonomous vehicles. Among the first automation layers, the safety layer plays a significant role in this field. However, considering safety should not diminish the importance of the efficiency of the vehicle in terms of path tracking with the desired speed. This thesis introduces a multi-constraint predictive control algorithm along with a safety layer to guarantee object avoidance in emergency situations. First, there is a quick review of autonomous cars and their functionalities. In the following, a controller switching mechanism is proposed and designed. It switches the …

Improving The Efficiency Of Planar Goubau Line And Goubau-Line-Based Endfire Antenna, Sreelakshmi Radhakrishnan

Graduate Research Theses & Dissertations

This thesis presents the use of two dielectric layers in a planar Goubau line (PGL) to improve its transmission efficiency compared to the existing single-layer models, which is less than 70% efficient at lower frequencies up to 5 GHz. Further, as an extension of the thesis, the possibility of obtaining directive radiation pattern with radiation efficiency greater than 89.6% using a Goubau-line-based antenna is studied. While none of the existing Goubau-line-based antennas are able to obtain an endfire pattern with radiation efficiency of above 80%, the proposed model utilizes stubs that are periodically attached to the main line of length …

Optimizing Cluster Sets For The Scan Statistic Using Local Search, James Shulgan

Graduate Research Theses & Dissertations

In recent years, scattering sensors to produce wireless sensor networks (WSN) has been proposed for detecting localized events in large areas. Because sensor measurements are noisy, the WSN needs to use statistical methods such as the scan statistic. The scan statistic groups measurements into various clusters, computes a cluster statistic for each cluster, and decides that an event has happened if any of the statistics exceeds a threshold. Previous researchers have investigated the performance of the scan statistic to detect events; however, little attention was given to the optimization of which clusters the scan statistic should use. Using the scan …

Magnetoquasistatic Resonances Of Small Dielectric Objects, Carlo Forestiere, Giovanni Miano, Guglielmo Rubinacci, Mariano Pascale, Antonello Tamburrino, Antonello Tamburrino, Roberto Tricarico, Salvatore Ventre

Advanced Science Research Center

A small dielectric object with positive permittivity may resonate when the free-space wavelength is large in comparison with the object dimensions if the permittivity is sufficiently high. We show that these resonances are described by the magnetoquasistatic approximation of the Maxwell's equations in which the normal component of the displacement current density field vanishes on the surface of the particle. They are associated to values of permittivities and frequencies for which source-free quasistatic magnetic fields exist, which are connected to the eigenvalues of a magnetostatic integral operator. We present the general physical properties of magnetoquasistatic resonances in dielectrics with arbitrary …

Demonstration Of A Quantized Acoustic Octupole Topological Insulator, Xiang Ni, Mengyao Li, Matthew Weiner, Andrea Alù, Alexander B. Khanikaev

Advanced Science Research Center

Recently introduced quantized multipole topological insulators (QMTIs) reveal new types of gapped boundary states, which themselves represent lower-dimensional topological phases and host symmetry protected zero-dimensional corner states. Inspired by these predictions, tremendous efforts have been devoted to the experimental observation of quantized quadrupole topological phase. However, due to stringent requirements of anti-commuting reflection symmetries, it is challenging to achieve higher-order quantized multipole moments, such as octupole moments, in a three-dimensional structure. Here, we overcome this challenge, and experimentally realize the acoustic analogue of a quantized octupole topological insulator using negatively coupled resonators. We confirm by first-principle studies that our design …

Demonstration Of A Third-Order Hierarchy Of Topological States In A Three-Dimensional Acoustic Metamaterial, Matthew Weiner, Xiang Ni, Mengyao Li, Andrea Alù, Alexander B. Khanikaev

Advanced Science Research Center

Classical wave systems have constituted an excellent platform for emulating complex quantum phenomena, such as demonstrating topological phenomena in photonics and acoustics. Recently, a new class of topological states localized in more than one dimension of a D-dimensional system, referred to as higher-order topological (HOT) states, has been reported, offering an even more versatile platform to confine and control classical radiation and mechanical motion. Here, we design and experimentally study a 3D topological acoustic metamaterial supporting third-order (0D) topological corner states along with second-order (1D) edge states and first-order (2D) surface states within the same topological bandgap, thus establishing …

Fault Detection And Classification Of A Single Phase Inverter Using Artificial Neural Networks, Ayomikun Samuel Orukotan

All Graduate Theses, Dissertations, and Other Capstone Projects

The detection of switching faults of power converters or the Circuit Under Test (CUT) is real-time important for safe and efficient usage. The CUT is a single-phase inverter. This thesis presents two unique methods that rely on backpropagation principles to solve classification problems with a two-layer network. These mathematical algorithms or proposed networks are able to diagnose single, double, triple, and multiple switching faults over different iterations representing range of frequencies. First, the fault detection and classification problems are formulated as neural network-based classification problems and the neural network design process is clearly described. Then, neural networks are trained over …

Performance Evaluation Of Long Range (Lora) Wireless Rf Technology For The Internet Of Things (Iot) Using Dragino Lora At 915 Mhz, Victor Hugo Lopez Chalacan

UNF Graduate Theses and Dissertations

Internet of Things (IoT) is a developing concept that introduces the network of physical sensors that are interconnected to each other. Within this smart environment, smart objects use the interconnectivity to process, communicate, and exchange data among themselves without any human interaction. Some sensors are wirelessly connected among themselves and to the internet. Currently, IoT applications demand substantial requirements in terms of Radio Access Network (RAN) such as long-range outdoor coverage, environmental factors, obstructions, interference, power consumption, and many others. Also, the current wireless technologies are not able to satisfy all these requirements simultaneously. Therefore, there is no single wireless …

Object Identification In Radar Imaging Via The Reciprocity Gap Method, Matthew Charnley, Aihua W. Wood

Faculty Publications

In this paper, we present an experimental method for locating and identifying objects in radar imaging, specifically problems that could arise in physical situations. The data for the forward problem are generated using a discretization of the Lippmann‐Schwinger equation, and the inverse problem of object location is solved using the reciprocity gap approach to the linear sampling method. The main new development in this paper is an exploration of determining the permittivity of the object from the back‐scattered data, utilizing another discretization of the Lippmann‐Schwinger equation.
Abstract © AGU.

Multi-Physics-Based Approach To Active Microwave Thermography, Seyed Ali Mirala

Doctoral Dissertations

“The goal of this work is to advance a novel nondestructive testing (NDT) method for controlled, rapid, and effective inspection of a structure through the integration of microwave NDT and thermography, referred to as Active Microwave Thermography (AMT). In AMT, the structure under test is exposed to microwave radiation and the thermal profile of the structure is monitored via a thermal camera in order to obtain desired information regarding the structure. This new technique is applicable across a wide range of NDT needs including detection of voids, delamination, water ingress, debonding, and cracks in numerous structures such as carbon fiber …

Mesh Networking And Full-Duplex Communication For Wireless Networks, Arul Mathi Maran Chandran

Doctoral Dissertations

“Connectivity with large coverage area; and an increase in spectral efficiency of communications are highly desired features for any wireless network. The presented research work addresses these two feature improvements. First, the work analyzed mesh networks to enhance connectivity for wireless networks. The work analyzed both homogeneous and heterogeneous mesh networks. The work includes the development of an Android application to enable smartphones with multiple interfaces, such as Wi-Fi, Bluetooth, and cellular services, to become convergence devices. These convergence devices are then used to build a heterogeneous mesh network improving connectivity and coverage area. Second, the work explored full-duplex communications, …

Accurate Modeling Techniques For Power Delivery, Jingdong Sun

Doctoral Dissertations

“Power delivery is essential in electronic systems to provide reliable power from voltage sources to load devices. Driven by the ambitious user demands and technology evolutions, the power delivery design is posed serious challenges. In this work, we focus on modeling two types of power delivery paths: the power distribution network (PDN) and the wireless power transfer (WPT) system.

For the modeling of PDN, a novel pattern-based analytical method is proposed for PCB-level PDN impedance calculations, which constructs an equivalent circuit with one-to-one correspondences to the PCB’s physical structure. A practical modeling methodology is also introduced to optimize the PDN …

Advanced Control Methods On Three-Phase Inverters In Distributed Energy Resources, Sara Yazdani

Doctoral Dissertations

“This research is an endeavor to apply new and well-established control methodologies to improve transient response, stability and reliability of three-phase inverters in grid-connected and isolated mode of operation. In the course of studying the effect of these methodologies, model-based control is introduced and is extensively applied which is relatively a new approach. In addition, the application of this concept has been studied on developing “grid-forming” controls to allow wind and solar inverters to support voltage and frequency levels like traditional generators.

This research encloses the details of three major works of this research and their possible contributions on improving …

Improved Attenuation And Crosstalk Modeling Techniques For High-Speed Channels, Shaohui Yong

Doctoral Dissertations

”As digital systems are moving in the direction of faster data transmission rate and higher density of circuits, the problem of the far-end crosstalk (FEXT) and frequency-dependent attenuation are becoming the major factors that limit signal integrity performance. This research is focusing on providing several more comprehensive and accurate modeling approaches for striplines on fabricated printed circuit board (PCB). By characterizing the dielectric permittivity of prepreg and core, dielectric loss tangent, and copper foil surface roughness using measurement data, a better agreement between the stripline model and measurement is achieved. First, a method is proposed to extract dielectric loss tangent …

System Efficient Esd Design Concept For Soft Failures, Giorgi Maghlakelidze

Doctoral Dissertations

"This research covers the topic of developing a systematic methodology of studying electrostatic discharge (ESD)-induced soft failures. ESD-induced soft failures (SF) are non-destructive disruptions of the functionality of an electronic system. The soft failure robustness of a USB3 Gen 1 interface is investigated, modeled, and improved. The injection is performed directly using transmission line pulser (TLP) with varying: pulse width, amplitude, polarity. Characterization provides data for failure thresholds and a SPICE circuit model that describes the transient voltage and current at the victim. Using the injected current, the likelihood of a SF is predicted. ESD protection by transient voltage suppressor …

Analysis And Modeling Of Power Supply Induced Jitter For High Speed Driver And Low Dropout Voltage Regulator, Yin Sun

Doctoral Dissertations

”With the scaling of power supply voltage levels and improving trans-conductance of drivers, the sensitivity of drivers to power supply induced delays has increased. The power supply induced jitter (PSIJ) has become one of the major concerns for high-speed system. In this work, the PSIJ analysis and modeling method are proposed for high speed drivers and the system with on-die low dropout (LDO) voltage regulator. In addition, a jitter-aware target impedance concept is proposed for power distribution network (PDN) design to correlate the PSIJ with PDN parasitic.

The proposed PSIJ analysis model is based on the driver power supply rejection …

Design And Fabrication Of Field-Effect Iii-V Schottky Junction Solar Cells, Amirhossein Ghods

Doctoral Dissertations

“A new concept of field-effect photovoltaic devices with a focus on design and fabrication of single and multi-junction solar cells using III-V materials has been shown and proved. Schottky solar cells based on metal-(insulator)-semiconductor (M-I-S) structure have been designed and fabricated using various wide bandgap semiconductors, such as GaAs and Al_0.3Ga_0.7As. A secondary bias layer has been introduced to the device structure, in which it creates additional band bending and subsequently depletion region at the flat band regions on the top surface of the device. It should be mentioned that the bias layer is designed to …

Investigation Of Wide Bandgap Semiconductors For Room Temperature Spintronic, And Photovoltaic Applications, Vishal Saravade

Doctoral Dissertations

"Suitability of wide bandgap semiconductors for room temperature (RT) spintronic, and photovoltaic applications is investigated.

Spin properties of metal-organic chemical vapor deposition (MOCVD) – grown gadolinium-doped gallium nitride (GaGdN) are studied and underlying mechanism is identified. GaGdN exhibits Anomalous Hall Effect at room temperature if it contains oxygen or carbon atoms but shows Ordinary Hall Effect in their absence. The mechanism for spin and ferromagnetism in GaGdN is a combination of intrinsic, metallic conduction, and carrier-hopping mechanisms, and is activated by oxygen or carbon centers at interstitial or similar sites. A carrier-related mechanism in MOCVD-grown GaGdN at room temperature makes …

Flux Expulsion In Niobium Superconducting Radio-Frequency Cavities Of Different Purity And Essential Contributions To The Flux Sensitivity, P. Dhakal, Gianluigi Ciovati, Alex Gurevich

Physics Faculty Publications

Magnetic flux trapped during the cooldown of superconducting radio-frequency cavities through the transition temperature due to incomplete Meissner state is known to be a significant source of radio-frequency losses. The sensitivity of flux trapping depends on the distribution and the type of defects and impurities which pin vortices, as well as the cooldown dynamics when the cavity transitions from a normal to superconducting state. Here we present the results of measurements of the flux trapping sensitivity on 1.3 GHz elliptical cavities made from large-grain niobium with different purity for different cooldown dynamics and surface treatments. The results show that lower …