Electrical and Computer Engineering Commons^™

Stable, Highly Luminescent Perovskite-Polymer Composites For Photonics Applications, Juan He

Electronic Theses and Dissertations

Metal halide perovskites (simplified as perovskites as below), particularly those in nanocrystal forms, have recently emerged as highly efficient, bandgap tunable photonics materials that can be easily solution processed at low cost for display, lighting or other energy conversion applications. However, the quick degradation of perovskite nanocrystals under external stresses or upon colloidal aggregations has been a major challenge for most applications where high reliability is normally required. In this thesis, we have explored a polymer swelling-deswelling microencapsulation (SDM) process that enables the dispersion, in-situ crystallization and subsequent surface passivation of perovskite nanocrystals in polymer matrices, and leads to ultrastable …

Computational Imaging With Limited Photon Budget, Zheyuan Zhu

Electronic Theses and Dissertations

The capability of retrieving the image/signal of interest from extremely low photon flux is attractive in scientific, industrial, and medical imaging applications. Conventional imaging modalities and reconstruction algorithms rely on hundreds to thousands of photons per pixel (or per measurement) to ensure enough signal-to-noise (SNR) ratio for extracting the image/signal of interest. Unfortunately, the potential of radiation or photon damage prohibits high SNR measurements in dose-sensitive diagnosis scenarios. In addition, imaging systems utilizing inherently weak signals as contrast mechanism, such as X-ray scattering-based tomography, or attosecond pulse retrieval from the streaking trace, entail prolonged integration time to acquire hundreds of …

Optical Sensing Of Structural Dynamics In Complex Media, Jose Rafael Guzman Sepulveda

Electronic Theses and Dissertations

Quantifying the structural dynamics of complex media is challenging because of the multiple temporal and spatial scales involved. Thanks to the ability to retrieve collective dynamics noninvasively, light scattering-based approaches are often the methods of choice. This dissertation discusses specific features of dynamic light scattering that utilizes spatio-temporal coherence gating. It is demonstrated that this optical fiber-based approach can operate over a large range of optical regimes and it has a number of unique capabilities such as an effective isolation of single scattering, a large sensitivity, and a high collection efficiency. Moreover, the approach also provides means for proper ensemble …

Hybrid Integration Of Second- And Third-Order Highly Nonlinear Waveguides On Silicon Substrates, Guillermo Fernando Camacho Gonzalez

Electronic Theses and Dissertations

In order to extend the capabilities and applications of silicon photonics, other materials and compatible technologies have been developed and integrated on silicon substrates. A particular class of integrable materials are those with high second- and third-order nonlinear optical properties. This work presents contributions made to nonlinear integrated photonics on silicon substrates, including chalcogenide waveguides for over an octave supercontinuum generation, and rib-loaded thin-film lithium niobate waveguides for highly efficient second-harmonic generation. Through the pursuit of hybrid integration of the two types of waveguides for applications such as on-chip self-referenced optical frequency combs, we have experimentally demonstrated fabrication integrability of …

Holographic Optical Elements For Visible Light Applications In Photo-Thermo-Refractive Glass, Fedor Kompan

Electronic Theses and Dissertations

This dissertation reports on design and fabrication of various optical elements in Photo-thermo-refractive (PTR) glass. An ability to produce complex holographic optical elements (HOEs) for the visible spectral region appears very beneficial for variety of applications, however, it is limited due to photosensitivity of the glass confined within the UV region. First two parts of this dissertation present two independent approaches to the problem of holographic recording using visible radiation. The first method involves modification of the original PTR glass rendering it photosensitive to radiation in the visible spectral region and, thus, making possible the recording of holograms in PTR …

Third-Order Optical Nonlinearities For Integrated Microwave Photonics Applications, Marcin Malinowski

Electronic Theses and Dissertations

The field of integrated photonics aims at compressing large and environmentally-sensitive optical systems to micron-sized circuits that can be mass-produced through existing semiconductor fabrication facilities. The integration of optical components on single chips is pivotal to the realization of miniature systems with high degree of complexity. Such novel photonic chips find abundant applications in optical communication, spectroscopy and signal processing. This work concentrates on harnessing nonlinear phenomena to this avail. The first part of this dissertation discusses, both from component and system level, the development of a frequency comb source with a semiconductor mode-locked laser at its heart. New nonlinear …

Vhf Transmitter Development For Wildlife Tracking, Bryan Westra

Masters Theses

Wildlife biologists often use collars with VHF transmitters to gather wildlife data. The purpose of this project is to determine the best approach to designing a wildlife tracking VHF transmitter on a Printed Circuit Board (PCB). A variety of frequency generation methods were considered for the transmitter, including transistor-based crystal oscillators and chip based solutions from the chip manufacturers Analog Devices and Silicon Labs. Prototypes of the feasible options were built and evaluated for cost, power consumption, efficiency, size, frequency range, signal bandwidth, and frequency stability. It was found that the Silicon Labs Si4010 chip was the best solution based …

Ict-Enabled Control And Energy Management Of Community Microgrids For Resilient Smart Grid Operation, Mahmoud Saleh

Dissertations and Theses

Our research has focused on developing novel controllers and algorithms to enhance the resilience of the power grid and increase its readiness level against major disturbances.

The U.S. power grid currently encounters two main challenges: (1) the massive and extended blackouts caused by natural disasters, such as hurricane Sandy. These blackouts have raised a national call to explore innovative approaches for enhanced grid resiliency. Scrutinizing how previous blackouts initiated and propagated throughout the power grid, the major reasons are lack of situational awareness, lack of real-time monitoring and control, underdeveloped controllers at both the transmission and distribution levels, and lack …

Improving Retrievals Of Crop Vegetation Parameters From Remote Sensing Data, Nathaniel Levitan

Dissertations and Theses

Agricultural systems are difficult to model because crop growth is driven by the strongly nonlinear interaction of Genotype x Environment x Management (G x E x M) factors. Due to the nonlinearity in the interaction of these factors, the amount of data necessary to develop and utilize models to accurately predict the performance of agricultural systems at an operational scale is large. Satellite remote sensing provides the potential to vastly increase the amount of data available for modelling agricultural systems as a result of its high revisit time and spatial coverage. Unfortunately, there have been significant difficulties in deploying remote …

Software Defined Radio For Hybrid Beamforming Applications, Jianyet Lee

Dissertations and Theses

Beamforming techniques have been deployed in both licensed networks such as LTE network and unlicensed network such as IEEE802.11ac WiFi. The scope of work for this thesis is to leverage the benefits of beamforming techniques and software defined radio platform in developing a fully functioning LTE testbed. The testbed can be further developed to specific application for drone-to-drone or D2D communication independent of intervention from base stations. Applying beamforming techniques to devices such as drones can solve poor quality signal detection at the receivers due to the interference signals generated by other devices in the attempt to communicate with the …

Enhancing The Resolution Of Imaging Systems By Spatial Spectrum Manipulation, Wyatt Adams

Dissertations, Master's Theses and Master's Reports

Much research effort has been spent in the 21st century on superresolution imaging techniques, methods which can beat the diffraction limit. Subwavelength composite structures called ``metamaterials" had initially shown great promise in superresolution imaging applications in the early 2000s, owing to their potential for nearly arbitrary capabilities in controlling light. However, for optical frequencies they are often plagued by absorption and scattering losses which can decay or destroy their interesting properties. Similar issues limit the application of other superresolution devices operating as effective media, or metal films that can transfer waves with large momentum by supporting surface plasmon polaritons. In …

Lithium-Ion Battery Degradation Evaluation Through Bayesian Network Method For Residential Energy Storage Systems, Khalid Khan

Dissertations, Master's Theses and Master's Reports

Batteries continue to infiltrate in innovative applications with the technological advancements led by Li-ion chemistry in the past decade. Residential energy storage is one such example, made possible by increasing efficiency and decreasing the cost of solar PV. Residential energy storage, charged by rooftop solar PV is tied to the grid, provides household loads. This multi-operation role has a significant effect on battery degradation. These contributing factors especially solar irradiation and weather conditions are highly variable and can only be explained with probabilistic analysis. However, the effect of such external factors on battery degradation is approached in recent literature with …

A Survey Of State-Of-The-Art Gan-Based Approaches To Image Synthesis, Shahram Latifi, Shirin Nasr Esfahani

Electrical & Computer Engineering Faculty Research

In the past few years, Generative Adversarial Networks (GANs) have received immense attention by researchers in a variety of application domains. This new field of deep learning has been growing rapidly and has provided a way to learn deep representations without extensive use of annotated training data. Their achievements may be used in a variety of applications, including speech synthesis, image and video generation, semantic image editing, and style transfer. Image synthesis is an important component of expert systems and it attracted much attention since the introduction of GANs. However, GANs are known to be difficult to train especially when …

Solving Galbrun’S Equation With A Discontinuous Galerkin Finite Element Method, Marcus Maeder, Andrew Peplow, Maximilian Meindl, Steffen Marburg

All Works

© S. Hirzel Verlag · EAA Over many years, scientists and engineers have developed a broad variety of mathematical formulations to investigate the propagation and interactions with flow of flow-induced noise in early-stage of product design and development. Beside established theories such as the linearized Euler equations (LEE), the linearized Navier–Stokes equations (LNSE) and the acoustic perturbation equations (APE) which are described in an Eulerian framework, Galbrun utilized a mixed Lagrange–Eulerian framework to reduce the number of unknowns by representing perturbations by means of particle displacement only. Despite the advantages of fewer degrees of freedom and the reduced effort to …

Improving Link Quality Estimation In Zigbee Networks, Srikar Meka

Graduate Research Theses & Dissertations

Estimation of links in a Wireless Sensor Network and using such estimates to decide between all the multiple paths available in a network is important. There are several link estimation methods available. This thesis evaluates the performance of PRR based method (P-success method), suggested in the ZigBee specification and LQI based method (LQI method) used by different organizations, in various scenarios. The performance of these two link cost estimation methods is also compared under Wi-Fi interference. This comparison is done using a network simulator (NS3). It is observed that, if there is no Wi-Fi interference, both the P-success and LQI …

The Effects Of Using A Mobile Digital Assistive Tutor For Circuit Analysis On Students’ Academic Achievement, Problem-Solving And Self-Efficacy, Kenie Moses

Graduate Research Theses & Dissertations

This experimental research study examined the effects of using a mobile learning environment (MLE) that provided scaffolded assistive tutoring on student achievement in a Circuit Analysis (Network Theory) course. It also aimed to examine the relationships between students’ user learning analytics and their learning outcomes. The design and development of the mobile app was based on the Model of Contingent Instruction and Metacognitive Support which critically applies scaffolding as its operative in transferring domain knowledge in expert to novice problem-solving.

This experimental research study collected data from eighty-three undergraduate college students who were randomly assigned into one of three groups …

Implementation And Evaluation Of Gated Recurrent Unit For Speech Separation And Speech Enhancement, Sagar V. Shah

Graduate Research Theses & Dissertations

Hearing aids, automatic speech recognition (ASR) and many other communication systems work well when there is just one sound source with almost no echo, but their performance degrades in situations where more speakers are talking simultaneously or the reverberation is high. Speech separation and speech enhancement are core problems in the field of audio signal processing. Humans are remarkably capable of focusing their auditory attention on a single sound source within a noisy environment, by de-emphasizing all other voices and interferences in surroundings. This capability comes naturally to us humans. However, speech separation remains a significant challenge for computers. It …

Highly Efficient Gan-Based Single-Phase Transformer-Less Pv Grid-Tied Inverter, Khaled Alatawi

Electronic Theses and Dissertations

Growing energy demand and environmental concerns have led to an increased interest in renewable energy resources to provide a sustainable and low carbon emission energy supply. Among these renewable energy resources, photovoltaic (PV) systems have been the focus of many scientific researchers. The most vital component of a PV system that needs to be improved is the power converter. Grid-tied transformer-less inverters have gained a lot of interest in recent years because of their higher efficiency, reduced volume and lower cost compared to traditional line transformer inverters.

This dissertation discusses single-phase transformer-less inverter challenges and provides solutions that could lead …

Ferrite Characterization Techniques & Particle Simulations For Semiconductor Devices, Nicholas Erickson

Doctoral Dissertations

"This dissertation is divided into three papers, covering two major topics. The first topic, techniques for ferrite characterization, is discussed over the course of two papers. The second topic, particle simulations for semiconductor devices, is discussed in the last paper. In the first paper, the method for extracting permeability from ferrite materials is discussed for the Keysight 16454A permeability extraction fixture, where the ferrite material to be characterized is assumed to be homogeneous. Then the method is updated to account for layered materials. The updated method is verified through full-wave simulations. In the second paper, a planar printed circuit board …

Hardware Architectures For Compact Microwave And Millimeter Wave Cameras, Matthew Jared Horst

Doctoral Dissertations

"Millimeter wave SAR imaging has shown promise as an inspection tool for human skin for characterizing burns and skin cancers. However, the current state-of-the-art in microwave camera technology is not yet suited for developing a millimeter wave camera for human skin inspection. Consequently, the objective of this dissertation has been to build the necessary foundation of research to achieve such a millimeter wave camera. First, frequency uncertainty in signals generated by a practical microwave source, which is prone to drift in output frequency, was studied to determine its effect on SAR-generated images. A direct relationship was found between the level …

Underwater Acoustic Communications And Adaptive Signal Processing, Mohammadhossein Behgam

Doctoral Dissertations

"This dissertation proposes three new algorithms for underwater acoustic wireless communications. One is a new tail-biting circular MAP decoder for full tail-biting convolution (FTBC) codes for very short data blocks intended for Internet of Underwater Things (IoUT). The proposed algorithm was evaluated by ocean experiments and computer simulations on both Physical (PHY) and Media access control (MAC) layers. The ocean experimental results show that without channel equalization, the full tail-biting convolution (FTBC) codes with short packet lengths not only can perform similarly to zero-tailing convolution (ZTC) codes in terms of bit error rate (BER) in the PHY layer. Computer simulation …

Efficient Estimation And Mitigation For Radio-Frequency Interference, Qiaolei Huang

Doctoral Dissertations

"With rapid innovations in Internet of Things (IoT) and wireless technology, more and more consumer electronic devices around the world are now connected to the internet. In a small form factor electronic device, there are plenty of potential noise sources such as System On Chip (SoC), high speed traces, flexible cables and power converters, etc. Those noise sources can possibly introduce radio frequency interference (RFI) issues. In this dissertation, a transfer function based calculation method is proposed to estimate radio frequency interference (RFI) problems. The derived equations can clearly decompose the RFI problem into two parts: the noise source and …

Recent Results From Nb₃Sn Single Cell Cavities Coated At Jefferson Lab, U. Pudasaini, M. J. Kelley, Gianluigi Ciovati, G.V. Eremeev, M. J. Kelley, C. E. Reece, Ishwari Prasad Parajuli, Md. Nizam Sayeed

Physics Faculty Publications

Because of superior superconducting properties (Tc ~ 18.3K, H_{s h}~ 425 mT and Δ ~ 3.1 meV) compared to niobium, Nb₃Sn promise better RF performance (Q₀ and E_acc) and/or higher operating temperature (2 K Vs 4.2 K) for SRF cavities. Nb₃Sn-coated SRF cavities are produced routinely by depositing a few micron-thick Nb₃Sn films on the interior surface of Nb cavities via tin vapor diffusion technique. Early results from Nb₃Sn cavities coated with this technique exhibited precipitous low field Q-slope, also known as Wuppertal slope. Several Nb₃Sn single cell cavities coated at JLab appeared to exhibit …

Solutions For Fermi Questions, November 2019: Question 1: Cell Phones Make Me Boil; Question 2: Charging The Phone, Larry Weinstein

Physics Faculty Publications

Answers to the Fermi questions:

How much water can you boil with the energy stored in a cell phone battery?

How much does the electrical energy for a cell phone cost each year?

Data Driven Intelligent Grid Stability Monitoring And Adaptive Emergency Response, Hasan Ul Banna

Graduate Theses, Dissertations, and Problem Reports (ETD)

Power grids are large cyber-physical systems with physical operation controlled and integrated through communications. The technological breakthroughs made by the availability of low-cost, high speed communications, larger storage spaces, greater internet bandwidths have led to increased attentions towards advantages of these systems. The use of Phasor Measurement Unit (PMU) in complex interconnected power system for monitoring and control has increased significantly. This has resulted in huge amounts of data and growing databases, thus gearing towards an era where utilities might encounter an enormous amount of data daily from their measurement units including sensitive information useful for daily operations. With increasing …

Design And Implementation Of Overcurrent Protection Relays Test Bench, Khalid Daud Khattak

Graduate Theses, Dissertations, and Problem Reports (ETD)

The electrical power simulator in Engineering Sciences Building (ESB) at WVU was dismantled in July 2018. The simulator was used as a teaching tool for EE students to conduct lab experiments. The power simulator employed electromechanical and microprocessor protection relays, manual isolation and industrial circuit breakers, switches, variable autotransformer (VARIAC), voltmeters and ammeters. During the dismantling, a lot of equipment was retrieved for future possible use. This led to the idea of designing and implementing a simple circuit on a test bench that can be used as a lab equipment to demonstrate the operation of overcurrent protection relays. It was …

Modeling Of Magnetic Resonance Wireless Electric Vehicle Charging, Erhuvwu Ayisire

College of Graduate Studies: Theses & Dissertations

Due to the fast-growing market for an electric vehicle, it is necessary that the drawbacks involved in electric vehicle technology should be overcome, therefore introducing a wireless charging technique which is more convenient as battery cost, recharge time and weight has been removed. Different wireless charging techniques for electric vehicles are discussed. This research work investigates the feasibility of wireless power transfer for Electric Vehicles by electromagnetic resonance coupling. Wireless power transfer (WPT) for Electric Vehicles by magnetic resonance coupling is of high priority due to its efficiency, high power transmission, and more considerable charging distance. Simulation results show the …

Danger-Aware Resource Management In V2x Network, Tsigigenet Dessalgn

College of Graduate Studies: Theses & Dissertations

IEEE 802.11p is one of the key technologies that enable dedicated short-range communications (DSRC) in intelligent transportation system (ITS) for safety on the road. The main challenge in vehicular communication is the large amount of data to be processed. As vehicle density and velocity increases, the data to be transmitted also increases. We proposed a protocol that reduces the number of data to be transmitted at every second according to the level of danger that the transmitter vehicle experiences. The proposed protocol measures inter-vehicle distance, as the representative of the danger of a vehicle, to determine the priority for transmission. …

In Situ Mutation For Active Things In The Iot Context, Noura Faci, Zakaria Maamar, Thar Baker, Emir Ugljanin, Mohamed Sellami

All Works

Copyright © 2018 by SCITEPRESS - Science and Technology Publications, Lda. All rights reserved This paper discusses mutation as a new way for making things, in the context of Internet-of-Things (IoT), active instead of being passive as reported in the ICT literature. IoT is gaining momentum among ICT practitioners who see a lot of benefits in using things to support users have access to and control over their surroundings. However, things are still confined into the limited role of data suppliers. The approach proposed in this paper advocates for 2 types of mutation, active and passive, along with a set …

Unmanned Aerial Vehicles Enabled Iot Platform For Disaster Management, Waleed Ejaz, Muhammad Awais Azam, Salman Saadat, Farkhund Iqbal, Abdul Hanan

All Works

© 2019 by the authors. Efficient and reliable systems are required to detect and monitor disasters such as wildfires as well as to notify the people in the disaster-affected areas. Internet of Things (IoT) is the key paradigm that can address the multitude problems related to disaster management. In addition, an unmanned aerial vehicles (UAVs)-enabled IoT platform connected via cellular network can further enhance the robustness of the disaster management system. The UAV-enabled IoT platform is based on three main research areas: (i) ground IoT network; (ii) communication technologies for ground and aerial connectivity; and (iii) data analytics. In this …