Engineering Commons^™

An Insurance Framework For Cyber-Physical Power Systems Considering Integrated Cybersecurity-Reliability Assessment, Pikkin Lau

Theses and Dissertations

Due to the development of cyber-physical systems for modernizing power grids, vulnerabilityassessment has become an emerging focus in power system security studies. With the increasing application of cyber-enabled technologies in power systems, modern power system is prevalently exposed to a wide gamut of cybersecurity threats. In this dissertation, the power supply reliability is evaluated considering the strategic allocation of defense resources and smart technologies. The optimal mixed strategies are formulated by the Stackelberg Security Game to allocate the defense resources on multiple targets subject to cyberattacks. Smart monitoring with preventive and corrective measures is able to boost the substation availability …

Advanced Analytics In Smart Manufacturing: Anomaly Detection Using Machine Learning Algorithms And Parallel Machine Scheduling Using A Genetic Algorithm, Meiling He

Theses and Dissertations

Industry 4.0 offers great opportunities to utilize advanced data processing tools by generating Big Data from a more connected and efficient data collection system. Making good use of data processing technologies, such as machine learning and optimization algorithms, will significantly contribute to better quality control, automation, and job scheduling in Smart Manufacturing. This research aims to develop a new machine learning algorithm for solving highly imbalanced data processing problems, implement both supervised and unsupervised machine learning auto-selection frameworks for detecting anomalies in smart manufacturing, and develop a genetic algorithm for optimizing job schedules on unrelated parallel machines. This research also …

A Deep Recurrent Neural Network With Iterative Optimization For Inverse Image Processing Applications, Masaki Ikuta

Theses and Dissertations

Many algorithms and methods have been proposed for inverse image processing applications, such as super-resolution, image de-noising, and image reconstruction, particularly with the recent surge of interest in machine learning and deep learning methods.

As for Computed Tomography (CT) image reconstruction, the most recently proposed methods are limited to image domain processing, where deep learning is used to learn the mapping between a true image data set and a noisy image data set in the image domain. While deep learning-based methods can produce higher quality images than conventional model-based algorithms, these methods have a limitation. Deep learning-based methods used in …

Design, Control, And Development Of A Multilevel Converter Medium Voltage Ac To Low Voltage Dc For Fleet Electric Vehicle Charge Station, Garry Jean-Pierre

Theses and Dissertations

There is a shift in the technology of vehicles from gas and diesel engines to electric vehicles(EVs). Approximately ten million EVs were available globally in 2020 and it is projected that number will reach 145 million by 2030. To power the increasing number of EVs, the number of EV charging stations is growing at a significant rate. In order to provide flexibility and longer driving ranges to customers, the trend is to install DC fast charging stations. These chargers demand high power at low voltage, which our existing electrical distribution system cannot accommodate without major upgrades. Currently, bulky transformers are …

Common-Mode Modeling Of Neutral Point Clamped Converter Based Dual Active Bridge, Ryan James Olson

Theses and Dissertations

Modern power converters designed with wide-bandgap semiconductors are known to generate substantial conducted electromagnetic interference as a side effect of high edge rate and high frequency switching. With the advancement in power electronic converters, the significant EMI challenges need to be addressed for distribution level power systems. The goal is to provide a computationally efficient method of EMI characterization for conducted emissions for this future generation of power distribution systems. The first step in making this possible is through creating an accurate EMI characterization platform for the neutral point clamped dual active bridge. In this thesis, a formalized common-mode modeling …

A High-Bandwidth, Spectrally Broad Photodetector Based On Optically-Induced Seebeck Effect, Niloufar Yavarishad

Theses and Dissertations

In this thesis, we engineered a fast response high bandwidth self-powered infrared photodetector based on optically induced Seebeck effect in Cd3As2 operating at room temperature. The metal-semimetal-metal device was subject to transient photo-response tests using high-frequency lock-in modulation techniques. Our photodetector demonstrates a Seebeck voltage under the off-center illumination of a laser with the wavelength of 1064 nm, due to a temperature gradient. The photocurrent is readily registered at a modulation frequency of 6 kHz and further analysis indicates the sensor intrinsic bandwidth is predicted to approach the terahertz range. The responsivity of the sensor is 0.27 mA/W at room …

Network Management, Optimization And Security With Machine Learning Applications In Wireless Networks, Mariam Nabil

Theses and Dissertations

Wireless communication networks are emerging fast with a lot of challenges and ambitions. Requirements that are expected to be delivered by modern wireless networks are complex, multi-dimensional, and sometimes contradicting. In this thesis, we investigate several types of emerging wireless networks and tackle some challenges of these various networks. We focus on three main challenges. Those are Resource Optimization, Network Management, and Cyber Security. We present multiple views of these three aspects and propose solutions to probable scenarios. The first challenge (Resource Optimization) is studied in Wireless Powered Communication Networks (WPCNs). WPCNs are considered a very promising approach towards sustainable, …

Real Time Simulation And Hardware In The Loop Methods For Power Electronics Power Distribution Systems, Michele Difronzo

Theses and Dissertations

System level testing of Power Electronics Power Distribution Systems (PEPDS) can be challenging when fine temporal resolution is required (time step below 100-200ns). In the recent years, our research group has proposed various methods to simulate in real-time PEPDS using FPGAs and time step as small as 50ns. While the proposed methods allow achieving the desired temporal resolution, they are extremely demanding in terms of resources usage and the size of the PEPDS that can be simulated on a single FPGA is strongly limited.

In this dissertation -work that takes as an example application the US Navy electric Ship Zonal …

Transport, Photoluminescence & Photoconduction Characteristics Of Free Standing Two-Dimensional Γ-Alumina & Titanium Superlattice Doped Two-Dimensional Γ-Alumina Grown By Graphene-Assisted Atomic Layer Deposition, Elaheh Kheirandish

Theses and Dissertations

This study presents a facile high-yield bottom-up fabrication, morphology, crystallographic and optoelectronic characterization of free-standing quasi-2D γ-alumina, a non van der Waals 2D material. The synthesis comprises a multi-cycle atomic layer deposition (ALD) of amorphous alumina on a porous interconnected graphene foam as a growth scaffold and removed next by annealing and sintering the alumina/graphene/alumina sandwich at ~ 800 °C in air . The crystallographic and structural characteristics of the formed non-van der Waals quasi 2D γ-alumina were studied by X-ray diffraction (XRD), selected area electron diffraction (SAED), and high-resolution transmission electron microscopy (HRTEM). This analysis revealed the synthesized 2D …

On-Chip Nanoscale Plasmonic Optical Modulators, Abdalrahman Mohamed Nader Abdelhamid

Theses and Dissertations

In this thesis work, techniques for downsizing Optical modulators to nanoscale for the purpose of utilization in on chip communication and sensing applications are explored. Nanoscale optical interconnects can solve the electronics speed limiting transmission lines, in addition to decrease the electronic chips heat dissipation. A major obstacle in the path of achieving this goal is to build optical modulators, which transforms data from the electrical form to the optical form, in a size comparable to the size of the electronics components, while also having low insertion loss, high extinction ratio and bandwidth. Also, lap-on-chip applications used for fast diagnostics, …

Feasibility Study Of Radio Frequency Microelectromechanical Filters For Space Operation, Karanvir Singh

Theses and Dissertations

Piezoelectric contour mode resonator technology has the unique advantage of combining low motional resistance with the ability to define multiple frequencies on the same substrate. Contour mode resonators can be mechanically coupled together to form robust band-pass filters for the next generation of GPS satellites with extreme size reduction compared to electrically coupled filters. Piezoelectric zinc oxide (ZnO) contour mode resonators have the potential for monolithic integration with current ZnO transistor further reducing size, power consumption, and cost of filter modules. Barium strontium titanate (BST) contour mode resonators have incredible frequency tunability due to the fundamental nature of the thin …

Fault Modeling And Test Vector Generation For Asic Devices Exposed To Space Single Event Environment, Ahmed Mohamed

Theses and Dissertations

This work aims at providing a concise automated flow to predict the effect of Single Event Transients (SETs) on ASIC chips by developing a method to characterize the circuit susceptibility to SET pulses propagation and then generation of the required input vectors that sensitize the victim paths. A new enhanced method for SET electrical propagation modeling is proposed and compared to a previously published analytical model. The method was applied on different standard cells libraries built over XFAB Xh018 technology and verified for accuracy against simulations. The new method showed enhancement in accuracy compared with previous work in literature. Industrial …

Wound Image Classification Using Deep Convolutional Neural Networks, Behrouz Rostami

Theses and Dissertations

Artificial Intelligence (AI) includes subfields like Machine Learning (ML) and DeepLearning (DL) and discusses intelligent systems that mimic human behaviors. ML has been used in a wide range of fields. Particularly in the healthcare domain, medical images often need to be carefully processed via such operations as classification and segmentation. Unlike traditional ML methods, DL algorithms are based on deep neural networks that are trained on a large amount of labeled data to extract features without human intervention. DL algorithms have become popular and powerful in classifying and segmenting medical images in recent years. In this thesis, we shall study …

Real Time License Plate Detection Based On Machine Learning, Yu-Liang Chiang

Theses and Dissertations

License Plate Recognition (LPR) is a very useful technology skill for our world, and also includes a wide range of applications. During my student life in the US, it is not common to see this kind of technology applied in the public parking lot. LPR has been researched for many years in Asia. There are a lot of LPR systems, which include different types of technologies, being used in Taiwan. In my point of view, those systems are still using the conventional technology, which does not involve artificial intelligence. In many applications, that makes it possible to make mistakes in …

Modular Multilevel Converters With Module-Level Energy Storage For Medium Voltage Applications, Bora Novakovic

Theses and Dissertations

This dissertation is on Modular Multilevel Converter (MMC) converter design and analysis and its integration with energy storage at the low voltage module-level. The developed converter concept and topology can be used in various applications especially for the support of intermittent renewable energy resources. The general converter structure is analyzed and extended to include integrated energy storage suitable but not limited to medium voltage applications. The behavior of the idealized structure is analyzed to obtain equations that govern general converter behavior and identify possible control loops. Detail mathematical switching model is developed for the MMC converter with generalized module structure. …

Charge Mitigation Technologies For Aircraft Platforms, Mitchell L. Rudy

Theses and Dissertations

Research into ion-based advanced propulsion systems, such as air-breathing Hall effect thrusters on high-velocity aircraft and ion-propelled thrusters on spacecraft, necessitates addressing accompanying residual electric charge accumulation on the ungrounded flight platform. An experimental testbed was constructed to assess charge mitigation technologies and their effectiveness on aircraft. A Van de Graaff generator provided static charge accumulation levels exceeding a megavolt when combined with a high voltage direct current source generator. This research attached an isolated airfoil structure to the Van de Graaff generator's lower terminal to measure the induced leakage current under various applied environmental conditions, including up to three …

Robust Scandium Aluminum Nitride Mems Resonators For L Band Operation In Orbital Environments, Israel W. Dunk

Theses and Dissertations

This thesis investigates AlN alloyed with scandium in a variety of resonator architectures including WEM, overtone WEM, LEM, and SAW that have the potential to achieve high levels of electrical performance and environmental robustness. SAW resonators operating near 370 MHz are fabricated on polycrystalline Sc_.37Al_.63N, and AlN with the resulting devices compared and conclusions drawn as to the merits of each material. The design and fabrication of SAW devices is discussed in detail, with the operating characteristics of these resonators then tested both electrically and mechanically. Mechanical characterisation includes analysis of vibration and shock effects on …

Surface Defect Detection In Aircraft Skin & Visual Navigation Based On Forced Feature Selection Through Segmentation, Tyler B. Hussey

Theses and Dissertations

Visual inspection of aircraft skin for surface defects is an area of maintenance that is particularly intensive for time and manpower. One novel way to combat this problem is through the use of computer vision and the advent of Artificial Neural Networks (ANN), or more specifically, semantic segmentation via Convolutional Neural Networks (CNN). The research in the paper explores the use of semantic segmentation of aerial imagery as a way to force feature selection onto key areas of an image that might be more likely to correspond under seasonal variations. Utilizing feature selection and matching on the masked aerial image …

Supporting Space Domain Awareness Through The Development And Analysis Of Space Object Detection Algorithms Employed By Ground-Based Telescopes, Connor A. Paw

Theses and Dissertations

Detection algorithms are instrumental in maintaining space domain awareness, specifically in the observation, monitoring, and categorization of unknown space objects. State of the art detection algorithms utilize a matched filter or a spatial correlator on long exposure image data to make pixel-wise detection decisions. This thesis investigates the advantages and practical potential of two different post-processing detection algorithms that can be employed by ground-based telescopes. The first algorithm explored is based on a long exposure Fourier domain processing technique, while the second is centered around frame selection from a series of short exposure images. The results of the experiments performed …

Commuting Compositions For Quantum Circuit Reduction, Brenna R. Cole

Theses and Dissertations

The US Air Force has been increasing the use of automation in its weapon systems to include the remotely piloted aircraft (RPA) platforms. The RPA career field has had issues with poor pilot retention due to job stressors. For example, RPA operators spend a lot of time and attention surveilling a suspect on the ground for many hours, so adding automation to this activity could help improve pilot retention. The research problem in this thesis attempted to automate the process of observing a ground target. This thesis presents a method termed conic ray tracing for determining visibility and occlusion of …

Perovskite Thin Films Annealed In Supercritical Fluids For Efficient Solar Cells, Gilbert Annohene

Theses and Dissertations

In the field of photovoltaics, scientists and researchers are working fervently to produce a combination of efficient, stable, low cost and scalable devices. Methylammonium lead trihalide perovskite has attracted intense interest due to its high photovoltaic performance, low cost, and ease of manufacture. Their high absorption coefficient, tunable bandgap, low-temperature processing, and abundant elemental constituent provide innumerable advantages over other thin film absorber materials. Since the perovskite film is the most important in the device, morphology, crystallization, compositional and interface engineering have been explored to boost its performance and stability. High temperatures necessary for crystallization of organic-inorganic hybrid perovskite films …

A General Framework For Characterizing And Evaluating Attacker Models For Cps Security Assessment, Christopher S. Deloglos, Christopher Deloglos

Theses and Dissertations

Characterizing the attacker’s perspective is essential to assessing the security posture and resilience of cyber-physical systems. The attacker’s perspective is most often achieved by cyber-security experts (e.g., red teams) who critically challenge and analyze the system from an adversarial stance. Unfortunately, the knowledge and experience of cyber-security experts can be inconsistent leading to situations where there are gaps in the security assessment of a given system. Structured security review processes (such as TAM, Mission Aware, STPA-SEC, and STPA-SafeSec) attempt to standardize the review processes to impart consistency across an organization or application domain. However, with most security review processes, the …