Engineering Commons^™

Optimization Of Human Interactions In The College Campus Model Via Simio Integration, Benjamin E. Chaback

Doctoral Dissertations and Master's Theses

College campuses are a significant part of life in some cities. Many students each year attend university, pursuing additional knowledge from faculty members. Both staff and faculty members rely on these students to have successful jobs and to ensure the university functions. Yet recently, more and more students are attending, leading to overcrowding, lower admission rates, and difficulty getting into good programs. Previous work exists on qualitative student affairs and quantitative retention data, yet little on using simulations to model this problem. This work aimed to (a) Determine the ability to successfully model human interactions/people flow on a college campus, …

Modeling, Simulation And Control Of Microrobots For The Microfactory., Zhong Yang

Electronic Theses and Dissertations

Future assembly technologies will involve higher levels of automation in order to satisfy increased microscale or nanoscale precision requirements. Traditionally, assembly using a top-down robotic approach has been well-studied and applied to the microelectronics and MEMS industries, but less so in nanotechnology. With the boom of nanotechnology since the 1990s, newly designed products with new materials, coatings, and nanoparticles are gradually entering everyone’s lives, while the industry has grown into a billion-dollar volume worldwide. Traditionally, nanotechnology products are assembled using bottom-up methods, such as self-assembly, rather than top-down robotic assembly. This is due to considerations of volume handling of large …

Modeling Of Quad-Station Module Cluster Tools Using Petri Nets, Aung Nay

Theses

The semiconductor industry is highly competitive, and with the recent chip shortage, the throughput of wafers has become more important than ever. One of the tools that the industry has deployed is to use of quad-station modules instead of the traditional single-station modules that allow for higher throughput and better wafer consistency by processing multiple wafers at the same time and distributing work. The industry trend is to use multiple transfer chamber robots to stack the quad-station modules in a series, particularly for etch products. In this work, the quad-station cluster tool wafer movement is modeled by using Petri net …

Closed Form Implicitly Integrated Models For Computationally Efficient Simulation Of Power Electronics, Andrew Wunderlich

Theses and Dissertations

This work describes novel closed-form, implicitly integrated (CF-implicit) models of switched-mode power converters which feature implicit integration but require no iterative numerical solving algorithm for evaluation because they are explicitly solved prior to model execution. The derived models capture the large-signal dynamic behavior of the power converters, so their use and accuracy are not limited to any one set of operating conditions. These models can be implemented in any computational environment, including directly on an existing embedded controller as a digital twin. Since no iterative solver is required, the models are highly computationally efficient and have a very predictable worst-case …

Data Center Power System Emulation And Gan-Based High-Efficiency Rectifier With Reactive Power Regulation, Jingjing Sun

Doctoral Dissertations

Data centers are indispensable for today's computing and networking society, which has a considerable power consumption and significant impact on power system. Meanwhile, the average energy usage efficiency of data centers is still not high, leading to significant power loss and system cost.

In this dissertation, effective methods are proposed to investigate the data center load characteristics, improve data center power usage efficiency, and reduce the system cost.

First, a dynamic power model of a typical data center ac power system is proposed, which is complete and able to predict the data center's dynamic performance. Also, a converter-based data center …

Integrating Fire Responses To Combat Wildfires, Jonathan Leonard Badal

Electrical Engineering

Each year wildfires cause significant loss of property, worsen people’s health, and destroy multiple ecosystems. On average, a wildfire season costs anywhere from 7.6-62.8 billion dollars due to fire containment, repair, and restoration [1]. It can take decades to recover from the crippling loss of land and take even longer to fully restore it. However, with the implementation of a robust early detection system, these losses can be significantly reduced. The current process for identifying wildfires involves visual identification, phone call alerts, and media tools primarily driven by park rangers and public reporting. Unfortunately, this system is not preventative and …

Characterization And Modeling Of Esd Events, Risk And Protection, Jianchi Zhou

Doctoral Dissertations

“The ESD (Electrostatic discharge) failures have been raising critical reliability problems in electronic devices design. However, not all the ESD scenarios have been specified by the IEC standard and the characterizations of the ESD risk for different scenarios are essential to evaluate the ESD robustness of the devices in the real word.

The insulation of plastic enclosures provides protection against ESD to the electronic system inside. However, seams between plastic parts are often unavoidable. Different plastic arrangements are constructed to investigate the spark length and current derivatives and to understand the ESD spark behavior for geometries having spark lengths longer …

Selective Neural Stimulation By Leveraging Electrophysiological Diversity And Using Alternative Stimulus Waveforms, Bemin Ghobreal

Dissertations

Efforts on finding the principle mechanism for selective neural stimulation have concentrated on segregating the neurons based on their size and other geometric factors. However, neuronal subtypes found in different parts of the nervous system also differ in their electrophysiological properties. The primary objective of this study is to investigate the feasibility of selective activation of neurons by leveraging the diversity seen in passive and active membrane properties.

Using both a local membrane model and an axon model based on the CRRSS, the diversity of electrophysiological properties is simulated by varying four model parameters (membrane leakage-Gleak and capacitance-Cm, temperature coefficient-Ktemp, …

Modeling And Optimization Algorithm For Sic-Based Three-Phase Motor Drive System, Ren Ren

Doctoral Dissertations

More electric aircraft (MEA) and electrified aircraft propulsion (EAP) becomes the important topics in the area of transportation electrifications, expecting remarkable environmental and economic benefits. However, they bring the urgent challenges for the power electronics design since the new power architecture in the electrified aircraft requires many benchmark designs and comparisons. Also, a large number of power electronics converter designs with different specifications and system-level configurations need to be conducted in MEA and EAP, which demands huge design efforts and costs. Moreover, the long debugging and testing process increases the time to market because of gaps between the paper design …

Energy Harvesting Using Flextensional Piezoelectric Energy Harvesters In Resonance And Off-Resonance Modes, Mohamed A. Shabara

Mechanical & Aerospace Engineering Theses & Dissertations

Energy harvesting technologies are integrated into various modern devices and systems. These systems include Artificial Intelligence (AI) systems, Internet of Things (IoT), various types of energy harvesters are integrated in many engineering applications such as automotive, aerospace and ocean engineering. In order to develop a fully functioning stand-alone system, it is essential to integrate it with a built in power source such as a battery or a power generator. Also, in many situations, city power sources might not be available. Therefore, reliable, renewable and sustainable local power generators are desired. Piezoelectric energy harvesting (PEH) technologies, which are piezoelectric material-based devices, …

Detection And Classification Of Vibrating Objects In Sar Images, Francisco German Perez Venegas

Electrical and Computer Engineering ETDs

The vibratory response of buildings and machines contains key information that can be exploited to infer their operating conditions and to diagnose failures. Furthermore, since vibration signatures observed from the exterior surfaces of structures are intrinsically linked to the type of machinery operating inside of them, the ability to monitor vibrations remotely can enable the detection and identification of the machinery.

This dissertation focuses on developing novel techniques for the detection and M-ary classification of vibrating objects in SAR images. The work performed in this dissertation is conducted around three central claims. First, the non-linear transformation that the micro-Doppler return …

Testing And Packaging For Mems Acoustic Emission Sensors, Ting-Hung Liu

USF Tampa Graduate Theses and Dissertations

The goal of this research is to improve the structure and dimension of the MEMS acoustic emission sensor. Acoustic emission sensor (AE sensor) based on the piezoelectric transducer is a well-developed technology in non-destructive testing that is widely used to determine permanent damage such as cracks and corrosions in buildings and structures. The AE sensor can be used to monitor cracks in structures and to check leakage in pressurized systems. The location of cracks in a structure or system leakage causes a high-frequency surface vibration while releasing ultrasonic energy. The frequency of this energy is typically between 30 kHz to …

Development Mems Acoustic Emission Sensors, Adrian Enrique Avila Gomez

USF Tampa Graduate Theses and Dissertations

The purpose of this research is to develop MEMS based acoustic emission sensors for structural health monitoring. Acoustic emission (AE) is a well-established nondestructive testing technique that is typically used to monitor for fatigue cracks in structures, leaks in pressurized systems, damages in composite materials or impacts. This technology can offer a precise evaluation of structural conditions and allow identification of imminent failures or minor failures that can be addressed by planned maintenances routines. AE causes a burst of ultrasonic energy that is measured as high frequency surface vibrations (30 kHz to 1 MHz) generated by transient elastic waves that …

Diffusion Modeling Of Impurities Through The Molybdenum Back Contact Of Cigs Solar Cells, Chinedum John Akwari

Electrical & Computer Engineering Theses & Dissertations

CIGS is a major technology in photovoltaics and depends heavily, as any other PV technology, on the capacity to achieve the highest efficiency possible to compete on the market. Alkaline elements, notably sodium and potassium, play a key role in this matter as they enhance the open circuit voltage and the fill factor of the CIGS solar cells. However, this effect exists only for very specific concentration of sodium and potassium. These impurities typically diffuse through the soda-lime glass substrate.

Via modeling of the SIMS data, we try to understand and predict the diffusion mechanisms of these impurities from the …

Linear Quadratic Optimal Control For A Cascaded Converters-Based Microgrid, Amlam Niragire

Graduate Theses and Dissertations

There is a constant transformation of the electric grid due to an ongoing interest in the deployment of renewable energy resources and electric microgrid formation. This transformation, though advantageous in many ways, poses great challenges for the energy industry and there must be a constant improvement in modeling, simulation, analysis and control techniques in order to characterize and optimize the system design and operation. In this light, the scope of this thesis is focused on developing a linear model, analyzing the stability and designing an optimal linear quadratic regulator (LQR) for a microgrid system. The microgrid system used is inspired …

Emi Measurement And Modeling Techniques For Complex Electronic Circuits And Modules, Satyajeet Shinde

Doctoral Dissertations

"This dissertation consists of four papers. In the first paper, a combined model for predicting the most critical radiated emissions and total radiated power due to the display signals in a TV by incorporating the main processing board using the Huygens Equivalence theorem and the radiation due to the flex cable based on active probe measurements was developed.

In the second paper, a frequency-tunable resonant magnetic field probe was designed in the frequency range 900-2260 MHz for near-field scanning applications for the radio frequency interference studies by using a varactor diode providing the required capacitance and the parasitic inductance of …

Modeling Of Two Dimensional Graphene And Non-Graphene Material Based Tunnel Field Effect Transistors For Integrated Circuit Design, Md Shamiul Fahad

LSU Doctoral Dissertations

The Moore’s law of scaling of metal oxide semiconductor field effect transistor (MOSFET) had been a driving force toward the unprecedented advancement in development of integrated circuit over the last five decades. As the technology scales down to 7 nm node and below following the Moore’s law, conventional MOSFETs are becoming more vulnerable to extremely high off-state leakage current exhibiting a tremendous amount of standby power dissipation. Moreover, the fundamental physical limit of MOSFET of 60 mV/decade subthreshold slope exacerbates the situation further requiring current transport mechanism other than drift and diffusion for the operation of transistors. One way to …

Quantitative Estimation Of Causality And Predictive Modeling For Precipitation Observation Sites And River Gage Sensors, Tri Vu Nguyen

LSU Master's Theses

This project seeks to investigate two questions: correlations from precipitation measurement sensors to river gage sensors, and predictive modeling of peak river gage heights during precipitation events. First, if correlations can be quantified, then a predictive model can be explored to predict peak water levels at river gage sensors, in response to precipitation inputs. Answering both research questions can provide early flood detection benefits and provide quantitative time assessments for flood risks. An extensive data-driven study was conducted across a geographical area of the U.S, spanning the time period 2008-2016 to identify river gage sensors that are closely correlated to …

Optimized Sizing And Placing Of Distributed Energy Resources (Ders) In An Island Microgrid Using Der-Cam, Bhuwan B. Bastola

Electrical and Computer Engineering ETDs

The electric grid at La Gomera, an island in the Canary archipelago, has been the subject of interest in optimized integration of Distributed Energy Resources (DERs) primarily because of high distribution losses and concerns about complying with emission regulations. Consequently, the utility that operates the island power system wishes to mitigate the problem with installation of renewable and distributed energy sources like PV and battery, which is the focus of this research.

Specifically, the focus of this thesis is to use Distributed Energy Resource - Customer Adoption Model (DER-CAM) to optimize the installation of PV and battery in terms of …

Modeling And Simulation Of 1700 V 8 A Genesic Superjunction Transistor, Staci E. Brooks

Graduate Theses and Dissertations

The first-ever 1.7kV 8A SiC physics-based compact SPICE model is developed for behavior prediction, modeling and simulation of the GeneSiC “Super” Junction Transistor. The model implements Gummel-Poon based equations and adds a quasi-saturation collector series resistance representation from a 1.2 kV, 6 A SiC bipolar junction transistor model developed in Hangzhou, China. The model has been validated with the GA08JT17-247 device data representing both static and dynamic characteristics from GeneSiC. Parameter extraction was performed in IC-CAP and results include plots showing output characteristics, capacitance versus voltage (C-V), and switching characteristics for 25 °C, 125 °C, and 175 °C temperatures.

Flight Control And Hardware Design Of Multi-Rotor Systems, Nathan M. Zimmerman

Master's Theses (2009 -)

This thesis overviews crucial concepts involved in achieving quadcopter flight such as orientation estimation and control system implementation. This thesis also presents researchers with comprehensive hardware and software specifications for a quadcopter system. The primary application for this system would be for research with regards to the implementation of advance control techniques as well as data acquisition. Key constructs of this system include hardware software specifications for a flight controller, the radio system, and the sensorless brushless motor controllers. Firstly, the thesis starts by developing a reference frame and a mathematical model for the quadcotper system. Next, flight orientation estimation …

Modeling And Loss Analysis Of Wide Bandgap Power Semiconductor Devices, Kang Peng

Theses and Dissertations

In recent times, the development of high power density and high efficiency power converters has become critical in power electronics applications like electric vehicles, aircrafts, electric ships and so on. High-switching-frequency and high-temperature operation are required to achieve this target. However, these requirements are exceeding the theoretical material-related limits of silicon (Si) based devices. The emerging wide bandgap power semiconductor technology is a promising solution to meet these requirements. Silicon Carbide (SiC) and Gallium Nitride (GaN) are the most promising among all wide bandgap semiconductor materials. SiC and GaN have almost a three times larger bandgap (about 3eV), compared with …

Enhancement Of Supercapacitor Energy Storage By Leakage Reduction And Electrode Modification, Tete Tevi

USF Tampa Graduate Theses and Dissertations

Supercapacitors have emerged in recent years as a promising energy storage technology. The main mechanism of energy storage is based on electrostatic separation of charges in a region at the electrode-electrolyte interface called double layer. Various electrode materials including carbon and conducting polymers have been used in supercapacitors. Also, supercapacitors offer high life cycle and high power density among electrochemical energy storage devices. Despite their interesting features, supercapacitors present some disadvantages that limit their competitivity with other storage devices in some applications. One of those drawbacks is high self-discharge or leakage. The leakage occurs when electrons cross the double layer …

Modeling, Simulation And Control Of Hybrid Electric Vehicle Drive While Minimizing Energy Input Requirements Using Optimized Gear Ratios, Sanjai Massey

Dissertations, Master's Theses and Master's Reports

This project was conducted to analyze (model and simulate) and optimize an electric motor based drive system to propel a typical passenger vehicle in an urban driving environment. Although there are many HEV and EV type systems on the market today, this paper chose the Toyota Prius HEV system as a baseline using a brushless AC motor.

Although a vehicle can be driven many ways, a more standardized Urban Dynamometer Driving Schedule, UDDS, was chosen to simulate real driving conditions. This schedule is determined by the US Environmental Protection Agency, EPA, and is intended to represent the city driving conditions …

Modeling And Control Of Fuel Cell-Battery Hybrid Energy Sources, Nima Lotfi

Doctoral Dissertations

"Environmental, political, and availability concerns regarding fossil fuels in recent decades have garnered substantial research and development in the area of alternative energy systems. Among various alternative energy systems, fuel cells and batteries have attracted significant attention both in academia and industry considering their superior performances and numerous advantages. In this dissertation, the modeling and control of these two electrochemical sources as the main constituents of fuel cell-battery hybrid energy sources are studied with ultimate goals of improving their performance, reducing their development and operational costs and consequently, easing their widespread commercialization. More specifically, Paper I provides a comprehensive background …

Saturable Reactor For Power Flow Control In Electric Transmission Systems: Modeling And System Impact Study, Marcus Aaron Young Ii

Doctoral Dissertations

A Saturable Reactor for Power Flow Control (SRPFC) is a novel application of a concept well known to electronics and power electronics engineers that provides continuous modulation of line reactance by controlling the magnetization in a ferromagnetic core. The novelty of the SRPFC is the target application, which is power flow control in meshed electric power networks. Modulation of the line impedance occurs by altering the current in a DC winding to control the magnetization of the ferromagnetic core, thereby varying the reactance of the AC winding. The deployment of power system equipment, like SRPFC, requires careful planning and study …

Microscopic Modeling Of Crowds Involving Individuals With Physical Disability: Exploring Social Force Interaction, Daniel S. Stuart

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nearly one quarter of a population is affected by a disability which influences crowd evacuation. Emergencies such as stampede or crowd crush can occur during evacuations. While research has investigated crowd evacuation, little has been researched involving individuals with disabilities. There is a need to understand and model individuals with disabilities in their interaction and how it impacts crowd movement. This dissertation creates a video tracking system to study heterogeneous crowds with individuals with disabilities towards conducting crowd experiments. A large-scale crowd experiment is conducted and the results are analyzed through a developed analysis graphical user interface. Preliminary results of …

A Methodology For Physically-Based Contact And Meniscus Properties In Rigid-Body Computational Knee Modeling, Stephen Wilson

Open Access Theses & Dissertations

Determining natural inner knee mechanics is a longstanding goal for researchers with applications to prevention and treatment of knee trauma and osteoarthritis. Physical testing has only provided limited information of knee mechanics due to technical challenges and cost. Modeling has been used for decades to obtain some of this otherwise inaccessible information, and recently finite element analysis (FEA) has become a popular means to this end. However, FEA requires time intensive mesh-creation and has large computational requirements. Ideally, model creation should be easy and simulations should be fast to allow for sensitivity analysis. Although allowing easier model creation and offering …

Modeling Of The Response Of A Memcapacitor For An Impulse, Step, Ramp, And Sinusiodal Inputs, Ghassan Khalil Kachmar

Open Access Theses & Dissertations

Micro-Electro-Mechanical Systems, or MEMS, is a technology of very small scale devices. The dimensions of MEMS can vary from below one micron to several millimeters. MEMS have some mechanical functionalities such as the moving plate of a parallel plate capacitor (memcapacitor). MEMS researchers and developers have demonstrated an extremely large number of microsensors for almost every possible sensing modality including temperature, pressure, inertial forces, and chemical species. The equation of motion of the moving plate of a memcapacitor is governed by a non-linear differential equation with no known exact solution. Most research into determining the theoretical response of a memcapacitor …

Multifrequency Averaging Of Hysteresis-Current-Controlled Dc-Dc Converters, Yingying Liu

Theses and Dissertations--Electrical and Computer Engineering

Multifrequency averaging is one of the widely used modeling and simulation techniques today for the analysis and design of power electronic systems. This technique is capable of providing the average behavior as well as the ripple behavior of power electronic systems. Hysteresis current control has fast response and internal current stability through controlling switches to maintain the current within a given hysteresis band of a given current command. However the state space variables in a hysteresis controlled system cannot be directly approached by multifrequency averaging method because of time varing switching frequency. In this thesis, a method of applying multifrequency …