Electrical and Computer Engineering Commons^™

Modeling And Simulation Of Iii-Nitride-Based Solar Cells Using Nextnano®, Malak Refaei

Graduate Theses and Dissertations

Nextnano³ software is a well-known package for simulating semiconductor band-structures at the nanoscale and predicting the general electronic structure. In this work, it is further demonstrated as a viable tool for the simulation of III-nitride solar cells. In order to prove this feasibility, the generally accepted solar cell simulation package, PC1D, was chosen for comparison. To critique the results from both PC1D and Nextnano3, the fundamental drift-diffusion equations were used to calculate the performance of a simple p-n homojunction solar cell device analytically. Silicon was picked as the material for this comparison between the outputs of the two simulators as …

A Parameterized Simulation Of Doppler Lidar, David B. Chester

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Upcoming missions to explore planetary bodies in the solar system will require accurate position and velocity data during descent in order to land safely at a predesignated site. A Doppler lidar instrument could provide measurements of the altitude, attitude, and velocity of the landing vehicle to supplement the data collected by other instruments. A flexible simulation tool would aid the tasks of designing and testing the functionality of such an instrument.

LadarSIM is a robust parameterized simulation tool developed for time of flight lidar at Utah State University's Center for Advanced Imaging Ladar. This thesis outlines how LadarSIM was modified …

Micro-Cantilever Based Fiber Optic Hydrophone, Jie Liu

All Dissertations

Endoscopic photoacoustic imaging probe is becoming increasingly important for many clinical photoacoustic imaging applications in which the target tissue can only be accessed by introducing an endoscopic probe percutaneously or through a natural orifice. Miniature fiber optic hydrophone (FOH) has become an attractive choice for endoscopic photoacoustic imaging application. Fiber optic hydrophone has many proven advantages, including small size, light weight, immunity to electromagnetic interference, low cost for single-use application and capability of integration of excitation light source and acoustic wave receiver.

This dissertation demonstrates an open cavity, micro-cantilever based fiber optic Fabry-Perot interferometer (FPI) hydrophone. A fused silica micro-cantilever …

Aliasing Of The Schumann Resonance Background Signal By Sprite-Associated Q-Bursts, Anirban Guha, Earle Williams, Robert Boldi, Gabriella Sátori, Tamás Nagy, József Bór, Joan Montanyà, Pascal Ortega

All Works

© 2017 The Authors The Earth's naturally occurring Schumann resonances (SR) are composed of a quasi-continuous background component and a larger-amplitude, short-duration transient component, otherwise called ‘Q-burst’ (Ogawa et al., 1967). Sprites in the mesosphere are also known to accompany the energetic positive ground flashes that launch the Q-bursts (Boccippio et al., 1995). Spectra of the background Schumann Resonances (SR) require a natural stabilization period of ∼10–12 min for the three conspicuous modal parameters to be derived from Lorentzian fitting. Before the spectra are computed and the fitting process is initiated, the raw time series data need to be properly …

The Field-Programmable Gate Array Design Of The Gridded Retarding Ion Distribution Sensor, Anthony P. Swenson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mankind's ability to predict weather on earth has been greatly enhanced by new instrumentation technology. Similarly, mankind's ability to predict space weather benefits from new technologies. Just as increasing the amount of atmospheric measurements on earth heightened mankind's ability to predict Earth weather, many scientists expect that expanding the amount of plasma measurements in space could be key to enhancing mankind's ability to predict space weather. Small satellites are one of these new technologies that have the potential to greatly enhance our ability to predict space weather. Utilizing many low-cost small satellites allows scientists to take data from more locations …

Impacts Of Distributions And Trajectories On Navigation Uncertainty Using Line-Of-Sight Measurements To Known Landmarks In Gps-Denied Environments, Ryan D. Lamoreaux

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Unmanned vehicles are increasingly common in our world today. Self-driving ground vehicles and unmanned aerial vehicles (UAVs) such as quadcopters have become the fastest growing area of automated vehicles research. These systems use three main processes to autonomously travel from one location to another: guidance, navigation, and controls (GNC). Guidance refers to the process of determining a desired path of travel or trajectory, affecting velocities and orientations. Examples of guidance activities include path planning and obstacle avoidance. Effective guidance decisions require knowledge of one’s current location. Navigation systems typically answer questions such as: “Where am I? What is my orientation? …

Bidirectional Three-Phase Ac-Dc Power Conversion Using Dc-Dc Converters And A Three-Phase Unfolder, Weilun Warren Chen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Strategic use of energy storage systems alleviates imbalance between energy generation and consumption. Battery storage of various chemistries is favorable for its relatively high energy density and high charge and discharge rates. Battery voltage is in dc, while the distribution of electricity is still predominantly in ac. To effectively harness the battery energy, a dc-ac inverter is required.

A conventional inverter contains two high-frequency switching stages. The battery-interfacing stage provides galvanic isolation and switches at high frequency to minimize the isolation transformer size. The grid-interfacing stage also operates at high frequency to obtain sinusoidal grid currents and the desired power. …

Characterization Of Mechanical Properties Of Battery Electrode Films From Acoustic Resonance Measurements, Kathryn Lanae Dallon

Theses and Dissertations

Measurements of the mechanical properties of lithium-ion battery electrode films can be used to quantify and improve manufacturing processes and to predict the mechanical and electrochemical performance of the battery. This thesis demonstrates the use of acoustic resonances to distinguish among commercial-grade battery films with different active electrode materials, thicknesses, and densities. Resonances are excited in a clamped circular area of the film using a pulsed infrared laser or speaker and responses are measured using an electret condenser microphone. A numerical model is used to quantify the sensitivity of resonances to changes in mechanical properties. When the numerical model is …

Phased-Array Feed Instrumentation And Processing For Astronomical Detection, Interference Mitigation, And Transient Parameter Estimation, Richard Allen Black

Theses and Dissertations

Radio astronomy, the survey and study of naturally occurring astronomical radio signals, is a challenging field in terms of engineering requirements. The typical astronomical signal of interest is incredibly faint, resulting in very low signal-to-noise ratios (SNRs) on the order of -30 dB or lower. To detect such signals, one must have an uncommonly low and stable receiver noise temperature, high gain through large aperture reflectors, and state-of-the-art signal processing algorithms. One must also be able to mitigate the effects of interference, the presence of which, even if extremely weak, can completely mask the faint astronomical signals of interest. To …

The Development Of Novel Interconnection Technologies For 3d Packaging Of Wire Bondless Silicon Carbide Power Modules, Sayan Seal

Graduate Theses and Dissertations

This dissertation advances the cause for the 3D packaging and integration of silicon carbide power modules. 3D wire bondless approaches adopted for enhancing the performance of silicon power modules were surveyed, and their merits were assessed to serve as a vision for the future of SiC power packaging. Current efforts pursuing 3D wire bondless SiC power modules were investigated, and the concept for a novel SiC power module was discussed. This highly-integrated SiC power module was assessed for feasibility, with a focus on achieving ultralow parasitic inductances in the critical switching loops. This will enable higher switching frequencies, leading to …

A High Accuracy Microwave Radiometric Thermometer To Measure Internal Body Temperature, Michael D. Grady

USF Tampa Graduate Theses and Dissertations

The Center for Disease Control and Prevention (CDC) released heat illness data which highlighted that ~29 heat stress hospitalizations and ~3 heat-related deaths occurred every day during the summer months within the US from years 2000 to 2014. Heatstroke- the most severe form of heat illness which oftentimes lead to death- has been cited to be entirely preventable if a timely intervention is introduced. This dissertation uses microwave radiometric thermometry to perform wireless non-invasive internal body temperature monitoring which can enable intervention methods that help to prevent deaths associated with heat-illness.

Overall, this dissertation develops a comprehensive closed-form analytical radiometric …

Graph-Based Latent Embedding, Annotation And Representation Learning In Neural Networks For Semi-Supervised And Unsupervised Settings, Ismail Ozsel Kilinc

USF Tampa Graduate Theses and Dissertations

Machine learning has been immensely successful in supervised learning with outstanding examples in major industrial applications such as voice and image recognition. Following these developments, the most recent research has now begun to focus primarily on algorithms which can exploit very large sets of unlabeled examples to reduce the amount of manually labeled data required for existing models to perform well. In this dissertation, we propose graph-based latent embedding/annotation/representation learning techniques in neural networks tailored for semi-supervised and unsupervised learning problems. Specifically, we propose a novel regularization technique called Graph-based Activity Regularization (GAR) and a novel output layer modification called …

Multi-Target Extension For Beacon Foraging Methods, Christopher Sanford, Ziong Jiao, Jae Oh

Electrical Engineering and Computer Science - All Scholarship

Robotic foraging is a complex problem that encompasses both the problem of exploring an area and retrieval of targets. To solve this, biologically inspired algorithms have been proposed that handle the scenario when only one target exists, but requires extension to multiple targets. In both scenarios there exists problems of robot allocation and congestion, and we analyze ways of optimizing both allocation and minimizing congestion for our algorithms. We demonstrate the results through parameterized metrics and compare the improvements in each scenario.

This is a technical report on artificial intelligence, 2017, written by Sanford, Jiao, and Oh.

Extending Motion Detection To Track Stopped Objects In Visual Multi-Target Tracking, Jacob H. White, Karl T. Salva, Randal W. Beard

Student Works

Various solutions to visual multi-target tracking have been proposed, but many of them are not capable of running in real time from a moving camera on an unmanned aerial vehicle (UAV). We present a tracker that runs in real time and tracks multiple objects while accounting for camera motion on a UAV. Our algorithm is capable of processing over 10 frames per second on a 1280x720 video sequence.

We utilize Recursive-RANSAC, an efficient algorithm for tracking multiple objects in clutter. Our work combines motion detection with optical flow and feature matching to allow stationary objects to be tracked. We use …

High Consequence Scenarios For North Korean Atmospheric Nuclear Tests With Policy Recommendations For The U.S. Government, Thomas S. Popik, Jordan T. Kearns, George H. Baker Iii, Henry F. Cooper, William R. Harris

School of Integrated Sciences - Faculty Scholarship

The government of North Korea has declared high-altitude EMP-capability to be a “strategic goal” and has also threatened an atmospheric test of a hydrogen bomb. Atmospheric nuclear tests have the potential to cripple satellites and the undersea cable networks critical to communication, and navigation necessary for trans-Pacific trade among the U.S., China, and other nations. When a nuclear warhead is detonated at high altitude, a series of electromagnetic pulses radiate downward within the line of sight of the blast. These pulses can disable equipment with miniature electronics and long conductors. Electric grid controls and transmission systems are especially vulnerable. Intense …

Design And Simulation Of An 8-Bit Successive Approximation Register Charge-Redistribution Analog-To-Digital Converter, Sumit K. Verma

Electrical Engineering Theses

The thesis initially investigates the history of the monolithic ADCs. The next chapter explores the different types of ADCs available in the market today. Next, the operation of a 4-bit SAR ADC has been studied. Based on this analysis, an 8-bit charge-redistribution SAR ADC has been designed and simulated with Multisim (National Instruments, Austin, TX). The design is divided into different blocks which are individually implemented and tested. Level-1 SPICE MOSFET models representative of 5μm devices were used wherever individual MOSFETs were used in the design. Finally, the power dissipation during the conversion period was also estimated. The supply voltage …

Classification Of Daily Activities For The Elderly Using Wearable Sensors, Jian Liu, Jeehoon Sohn, Sukwon Kim

Computer Sciences and Electrical Engineering Faculty Research

Monitoring of activities of daily living (ADL) using wearable sensors can provide an objective indication of the activity levels or restrictions experienced by patients or elderly. The current study presented a two-sensor ADL classification method designed and tested specifically with elderly subjects. Ten healthy elderly were involved in a laboratory testing with 6 types of daily activities. Two inertial measurement units were attached to the thigh and the trunk of each subject. The results indicated an overall rate of misdetection being 2.8%. The findings of the current study can be used as the first step towards a more comprehensive activity …

Load Model Verification, Validation And Calibration Framework By Statistical Analysis On Field Data, Xiangqing Jiao, Yuan Liao, Thai Nguyen

Electrical and Computer Engineering Faculty Publications

Accurate load models are critical for power system analysis and operation. A large amount of research work has been done on load modeling. Most of the existing research focuses on developing load models, while little has been done on developing formal load model verification and validation (V&V) methodologies or procedures. Most of the existing load model validation is based on qualitative rather than quantitative analysis. In addition, not all aspects of model V&V problem have been addressed by the existing approaches. To complement the existing methods, this paper proposes a novel load model verification and validation framework that can systematically …

Direct Digital Manufacturing Of Multi-Layer Wideband Ku-Band Patch Antennas, Merve Kacar

USF Tampa Graduate Theses and Dissertations

Design and performance of fully-printed Ku-band aperture coupled patch antennas fabricated by a direct digital manufacturing (DDM) approach that integrates fused deposition modeling (FDM) of acrylonitrile butadiene styrene (ABS) thermoplastic with in-situ micro-dispensing of conductive silver paste (CB028) are reported. Microstrip line characterizations are performed and demonstrate that misalignment of ABS substrate deposition direction with microstrip line micro-dispensing direction can degrade the effective conductivity up to 60% within the Ku-band, and must be taken into consideration in antenna array feed network designs. Specically, over 125 µm thick ABS substrate, RF loss of 0.052 dB/mm is obtained at 18 GHz, demonstrating …

Design And Simulation Of A Miniature Cylindrical Mirror Auger Electron Energy Analyzer With Secondary Electron Noise Suppression, Jay A. Bieber

USF Tampa Graduate Theses and Dissertations

In the nanoscale metrology industry, there is a need for low-cost instruments, which have the ability to probe the structrure and elemental composition of thin films. This dissertation, describes the research performed to design and simulate a miniature Cylindrical Mirror Analyzer, (CMA), and Auger Electron Spectrometer, (AES). The CMA includes an integrated coaxial thermionic electron source. Electron optics simulations were performed using the Finite Element Method, (FEM), software COMSOL. To address the large Secondary Electron, (SE), noise, inherent in AES spectra, this research also included experiments to create structures in materials, which were intended to suppress SE backgound noise in …

Comparison Of Lithium-Ion Anode Materials Using An Experimentally Verified Physics-Based Electrochemical Model, Rujian Fu, Xuan Joe Zhou, Hengbin Fan, Douglas Blaisdell, Ajay Jagadale, Xi Zhang, Rui Xiong

Electrical & Computer Engineering Publications

Researchers are in search of parameters inside Li-ion batteries that can be utilized to control their external behavior. Physics-based electrochemical model could bridge the gap between Li+ transportation and distribution inside battery and battery performance outside. In this paper, two commercially available Li-ion anode materials: graphite and Lithium titanate (Li4Ti5O12 or LTO) were selected and a physics-based electrochemical model was developed based on half-cell assembly and testing. It is found that LTO has a smaller diffusion coefficient (Ds) than graphite, which causes a larger overpotential, leading to a smaller capacity utilization and, correspondingly, a shorter duration of constant current charge …

Design Of Post-Consumer Modification Of Standard Solar Modules To Form Large-Area Building-Integrated Photovoltaic Roof Slates, Joshua M. Pearce, Jay Meldrum, Nolan Osborne

Department of Materials Science and Engineering Publications

Building-integrated photovoltaic (BIPV) systems have improved aesthetics but generally cost far more than conventional PV systems because of small manufacturing scale. Thus, in the short and medium term, there is a need for a BIPV mounting system that utilizes conventional modules. Such a design is provided here with a novel modification of conventional photovoltaic (PV) modules to allow them to act as BIPV roofing slates. The open-source designs for the mechanical components necessary to provide the post-consumer conversion for a conventional PV module are provided, and prototypes are fabricated and installed on a mock roof system along with control modules …

Non-Orthogonal Multiple Access In A Mmwave Based Iot Wireless System With Swipt, Haijian Sun, Qun Wang, Shakil Ahmed, Rose Qingyang Hu

Electrical and Computer Engineering Student Research

This paper applies non-orthogonal multiple access (NOMA) and relaying schemes in a mmWave based wireless heterogeneous system that aims to support Internet of Things (IoT) applications. The system consists of high power base stations, low-power relays, and low-power IoT devices. Due to the ad hoc deployment nature of low-power relays, they have very limited access to wireline power charging facilities. Furthermore, IoT devices normally have limited power and short battery life. The study assumes low-power relays and IoT devices are capable of energy harvest functionality. With the help of relays or IoT devices, downlink NOMA transmission consists of two phases. …

Compact And Wideband Mmic Phase Shifters Using Tunable Active Inductor Loaded All-Pass Networks, David M. Zaiden

USF Tampa Graduate Theses and Dissertations

This dissertation addresses the design of monolithically integrated phase shifters at S- and L- frequency bands using a commercially available GaAs process from Triquint. The focus of the design is to operate over a wide bandwidth with full 360° phase shift capability, 50 Ω input/output impedance match and low RMS phase and gain errors. The first version of the design is based on passive all-pass phase shifters integrated with wideband amplifiers to compensate for insertion loss. This design uses a 4-bit system to achieve the required phase shift and each bit consists of 3 sections of all-pass filters designed at …

New Multi-Resolution Shortest-Path Navigation Techniques Using The Ndvi Imagery, Rui Tian

LSU Master's Theses

In this thesis work, we study the visible-light and near-infrared images for practical applications. Different colormaps, contours, or pixel-based indicators can be extracted from these optical images. Among them, normalized difference vegetation index (NDVI) has been widely utilized for applications in vegetation-health monitoring, geological survey, and climate forecast, etc. recently. We extend the use of NDVI for the navigation over the uncharted geographical areas. Henceforth, we propose a new algorithm which is called multi-resolution Dijkstra algorithm to find the approximate shortest paths within the large planar graphs representing the real terrains.

The outline of this thesis is briefed as follows. …

Physical Layer Algorithms For Reliability And Spectral Efficiency In Wireless Communications, Zekeriyya Esat Ankarali

USF Tampa Graduate Theses and Dissertations

Support of many different services, approximately 1000x increase of current data rates, ultra-reliability, low latency and energy/cost efficiency are among the demands from upcoming 5G standard. In order to meet them, researchers investigate various potential technologies involving different network layers and discuss their trade-offs for possible 5G scenarios. Waveform design is a critical part of these efforts and various alternatives have been heavily discussed over the last few years. Besides that, wireless technology is expected to be deployed in many critical applications including the ones involving with daily life activities, health-care and vehicular traffic. Therefore, security of wireless systems is …

Integration Of Thin Film Tpv Cells To Cvd Diamond Heat Spreaders, Emma J. Renteria

Electrical and Computer Engineering ETDs

In this work, techniques to isolate thermophotovoltaic (TPV) devices from the growth substrate and their subsequent integration with Chemical Vapor Deposition (CVD) diamond heat spreaders will be discussed, with the envisioned goal of fabricating thermally managed cells. CVD diamond heat spreaders are a great option for thermal management of TPV cells. The key requirement, however, is the bonding of the TPV cell directly onto the diamond wafer without the presence of thick (>350 μm) growth substrates, which can offer significant thermal resistance.

The first approach is to release GaSb epitaxial layers from GaSb substrates. However, this is challenging due …

Investigating Scalable Manufacturing Of High-Conductivity Wires And Coatings From Ultra-Long Carbon Nanotubes, Pouria Khanbolouki

Mechanical Engineering ETDs

Carbon nanotubes (CNTs) are a promising candidate for next generation of electrical wirings and electromagnetic interference (EMI) shielding materials due to their exceptional mechanical and electrical properties. Wires and coatings from ultralong nanotubes that are highly crystalline, well-aligned and densely packed can achieve this goal. High-performance CNT conductors will be relatively lightweight and resistant to harsh conditions and therefore can potentially replace current conductors in many industries including aerospace, automotive, gas and oil.

This thesis investigates a new manufacturing approach, based on conventional solution coating and wire drawing methods, to fabricate high conductivity wires and coatings from ultra-long carbon nanotubes. …

Modeling Of A Battery Storage System On A Distribution Feeder, Aaron M. Griego

Electrical and Computer Engineering ETDs

Driven by the need to reduce harmful emissions and the desire to move away from our dependency on fossil fuels, we have seen a sharp increase in alternative energy research and development within the last decade. Amongst the many alternative energy sources, photovoltaics (PV) is becoming more commonplace in the power utility system.

With these new sources of renewable energy being widely adopted, there are causes for concern that power utility companies must address. One of the more present issues that have been noted is the reliability of the power being delivered; in particular with PV systems. Studies have shown …

High Power Microwave Metamaterial Based Passive And Active Devices, Hamide Seidfaraji

Electrical and Computer Engineering ETDs

The goal of this dissertation is to design novel metamaterials for High Power Microwave devices. Metamaterials (MTM) are artificial periodic structures, which support reversed Cherenkov radiation and backward wave propagation. Microwave sources transform the kinetic energy of an electron beam into microwaves through the interaction of the electrons with a periodic slow wave structures (SWS). Here, a metamaterial (MTM) waveguide is proposed for use in a microwave oscillator instead of a SWS. The interaction of a multi-beam cathode with a set of MTM structures inside a cylindrical waveguide is studied and analyzed.

Group theory is used to design a metamaterial …