Engineering Commons^™

Novel High Isolation Antennas For Simultaneous Transmit And Receive (Star) Applications, Alexander Hovsepian

FIU Electronic Theses and Dissertations

Radio frequency (RF) spectrum congestion is a major challenge for the growing need of wireless bandwidth. Notably, in 2015, the Federal Communications Commission (FCC) auctioned just 65 MHz (a bandwidth smaller than that used for WiFi) for more than $40 billion, indicating the high value of the microwave spectrum. Current radios use one-half of their bandwidth resource for transmission, and the other half for reception. Therefore, by enabling radios to transmit and receive across their entire bandwidth allocation, spectral efficiency is doubled. Concurrently, data rates for wireless links also double. This technology leads to a new class of radios and …

Engineering Electromagnetic Systems For Next-Generation Brain-Machine Interface, Brayan Ricardo Navarrete

FIU Electronic Theses and Dissertations

MagnetoElectric Nanoparticles (MENPs) are known to be a powerful tool for a broad range of applications spanning from medicine to energy-efficient electronics. MENPs allow to couple intrinsic electric fields in the nervous system with externally controlled magnetic fields. This thesis exploited MENPs to achieve contactless brain-machine interface (BMIs). Special electromagnetic devices were engineered for controlling the MENPs’ magnetoelectric effect to enable stimulation and recording. The most important engineering breakthroughs of the study are summarized below.

(I) Metastable Physics to Localize Nanoparticles: One of the main challenges is to localize the nanoparticles at any selected site(s) in the brain. The fundamental …

Digital And Mixed Domain Hardware Reduction Algorithms And Implementations For Massive Mimo, Najath A. Mohomed

FIU Electronic Theses and Dissertations

Emerging 5G and 6G based wireless communications systems largely rely on multiple-input-multiple-output (MIMO) systems to reduce inherently extensive path losses, facilitate high data rates, and high spatial diversity. Massive MIMO systems used in mmWave and sub-THz applications consists of hundreds perhaps thousands of antenna elements at base stations. Digital beamforming techniques provide the highest flexibility and better degrees of freedom for phased antenna arrays as compared to its analog and hybrid alternatives but has the highest hardware complexity.

Conventional digital beamformers at the receiver require a dedicated analog to digital converter (ADC) for every antenna element, leading to ADCs for …

A Multimodal Neuroimaging Approach For Classification And Prediction Of Alzheimer's Disease Using Machine Learning, Parisa Forouzannezhad

FIU Electronic Theses and Dissertations

Alzheimer’s disease (AD) is one of the most common neurodegenerative disorders among the elderly population. It is progressive, irreversible in nature, and is considered the main cause of dementia. AD has become a world health problem affecting developed and developing nations alike, with the number of diagnosed AD patients increasing rather dramatically as both the life span of humans and the earth’s population continue to increase. Therefore, AD diagnosis in its earliest manifestations, preferably at the presymptomatic stage is critical for the timely planning of treatment and therapeutic interventions. We introduce new machine learning algorithms to detect and predict Alzheimer’s …

Defense By Deception Against Stealthy Attacks In Power Grids, Md Hasan Shahriar

FIU Electronic Theses and Dissertations

Cyber-physical Systems (CPSs) and the Internet of Things (IoT) are converging towards a hybrid platform that is becoming ubiquitous in all modern infrastructures. The integration of the complex and heterogeneous systems creates enormous space for the adversaries to get into the network and inject cleverly crafted false data into measurements, misleading the control center to make erroneous decisions. Besides, the attacker can make a critical part of the system unavailable by compromising the sensor data availability. To obfuscate and mislead the attackers, we propose DDAF, a deceptive data acquisition framework for CPSs' hierarchical communication network. Each switch in the hierarchical …

Efficient, High Power Density, Modular Wide Band-Gap Based Converters For Medium Voltage Application, Hadi Moradisizkoohi

FIU Electronic Theses and Dissertations

Recent advances in semiconductor technology have accelerated developments in medium-voltage direct-current (MVDC) power system transmission and distribution. A DC-DC converter is widely considered to be the most important technology for future DC networks. Wide band-gap (WBG) power devices (i.e. Silicon Carbide (SiC) and Gallium Nitride (GaN) devices) have paved the way for improving the efficiency and power density of power converters by means of higher switching frequencies with lower conduction and switching losses compared to their Silicon (Si) counterparts. However, due to rapid variation of the voltage and current, di/dt and dv/dt, to fully utilize the advantages of the Wide-bandgap …

Sensor Approach For Brain Pathophysiology Of Freezing Of Gait In Parkinson's Disease Patients, Juan Sebastian Marquez Jaramillo

FIU Electronic Theses and Dissertations

Parkinson's Disease (PD) affects over 1% of the population over 60 years of age and is expected to reach 1 million in the USA by the year 2020, growing by 60 thousand each year. It is well understood that PD is characterized by dopaminergic loss, leading to decreased executive function causing motor symptoms such as tremors, bradykinesia, dyskinesia, and freezing of gait (FoG) as well as non-motor symptoms such as loss of smell, depression, and sleep abnormalities. A PD diagnosis is difficult to make since there is no worldwide approved test and difficult to manage since its manifestations are widely …

Novel Conformal Strongly Coupled Magnetic Resonance Systems, Juan C. Barreto Jr

FIU Electronic Theses and Dissertations

Wireless Power Transfer (WPT) is an emerging technology in today’s society. Recently, many advancements to WPT systems have been implemented, such as, the introduction of the Strongly Coupled Magnetic Resonance (SCMR) and Conformal SCMR (CSCMR) methods. These methods allow WPT systems to operate at increased distances with smaller dimensional footprints. However, their range is still limited and needs to be expanded, and their footprint is sometimes large and needs to be miniaturized. Therefore, the goal of this research is to develop new designs and methodologies that can achieve the range extension and miniaturization of CSCMR systems.

Furthermore, many wireless devices …

Solving Complex Data-Streaming Problems By Applying Economic-Based Principles To Mobile And Wireless Resource Constraint Networks, Concepcion Z. Sanchez Aleman

FIU Electronic Theses and Dissertations

The applications that employ mobile networks depend on the continuous input of reliable data collected by sensing devices. A common application is in military systems, where as an example, drones that are sent on a mission can communicate with each other, exchange sensed data, and autonomously make decisions. Although the mobility of nodes enhances the network coverage, connectivity, and scalability, it introduces pressing issues in data reliability compounded by restrictions in sensor energy resources, as well as limitations in available memory, and computational capacity.

This dissertation investigates the issues that mobile networks encounter in providing reliable data. Our research goal …

Structural Health Monitoring Of Pipelines In Radioactive Environments Through Acoustic Sensing And Machine Learning, Michael Thompson

FIU Electronic Theses and Dissertations

Structural health monitoring (SHM) comprises multiple methodologies for the detection and characterization of stress, damage, and aberrations in engineering structures and equipment. Although, standard commercial engineering operations may freely adopt new technology into everyday operations, the nuclear industry is slowed down by tight governmental regulations and extremely harsh environments. This work aims to investigate and evaluate different sensor systems for real-time structural health monitoring of piping systems and develop a novel machine learning model to detect anomalies from the sensor data. The novelty of the current work lies in the development of an LSTM-autoencoder neural network to automate anomaly detection …

A Comprehensive Security Framework For Securing Sensors In Smart Devices And Applications, Amit Kumar Sikder

FIU Electronic Theses and Dissertations

This doctoral dissertation introduces novel security frameworks to detect sensor-based threats on smart devices and applications in smart settings such as smart home, smart office, etc. First, we present a formal taxonomy and in-depth impact analysis of existing sensor-based threats to smart devices and applications based on attack characteristics, targeted components, and capabilities. Then, we design a novel context-aware intrusion detection system, 6thSense, to detect sensor-based threats in standalone smart devices (e.g., smartphone, smart watch, etc.). 6thSense considers user activity-sensor co-dependence in standalone smart devices to learn the ongoing user activity contexts and builds a context-aware model to distinguish malicious …

Optimal And Secure Electricity Market Framework For Market Operation Of Multi-Microgrid Systems, Mohammad Mahmoudian Esfahani

FIU Electronic Theses and Dissertations

Traditional power systems were typically based on bulk energy services by large utility companies. However, microgrids and distributed generations have changed the structure of modern power systems as well as electricity markets. Therefore, restructured electricity markets are needed to address energy transactions in modern power systems.

In this dissertation, we developed a hierarchical and decentralized electricity market framework for multi-microgrid systems, which clears energy transactions through three market levels; Day-Ahead-Market (DAM), Hour-Ahead-Market (HAM) and Real-Time-Market (RTM). In this market, energy trades are possible between all participants within the microgrids as well as inter-microgrids transactions. In this approach, we developed a …

Efficient Key Management Schemes For Smart Grid, Mumin Cebe

FIU Electronic Theses and Dissertations

With the increasing digitization of different components of Smart Grid by incorporating smart(er) devices, there is an ongoing effort to deploy them for various applications. However, if these devices are compromised, they can reveal sensitive information from such systems. Therefore, securing them against cyber-attacks may represent the first step towards the protection of the critical infrastructure. Nevertheless, realization of the desirable security features such as confidentiality, integrity and authentication relies entirely on cryptographic keys that can be either symmetric or asymmetric. A major need, along with this, is to deal with managing these keys for a large number of devices …

Understanding The Effects Of Plasma Assisted Nanoparticle Deposition For The Enhancement Of Optical And Electrochemical Response, Apurva Sonawane

FIU Electronic Theses and Dissertations

In this work, the effects of atmospheric plasma treatment on morphology, optical, and electrochemical properties of 10 ± 3nm spherical silver and gold nanoparticles (AgNPs and AuNPs) functionalized substrates were studied. The nanoparticles (NPs) were deposited on substrates by drop-casting, aerosol spray, and a low-temperature atmospheric plasma-assisted aerosol jet. The reduction in nanoparticle size was observed, which was explained by the redox reaction that occurs on the nanoparticle surface. This phenomenon was evident by the presence of AgO, Ag₂O, and AuO_x Raman peaks in the treated sample. The surface charge changed as a result of plasma treatment, …

Nanoelectronic Applications Of Magnetoelectric Nanostructures, Ping Wang

FIU Electronic Theses and Dissertations

The greatly increased interest in magnetoelectric materials over the last decade is due to their potential to enable next-generation multifunctional nanostructures required for revolutionizing applications spanning from energy-efficient information processing to medicine. Magnetoelectric nanomaterials offer a unique way to use a voltage to control the electron spin and, reciprocally, to use remotely controlled magnetic fields to access local intrinsic electric fields. The magnetoelectric coefficient is the most critical indicator for the magnetoelectric coupling in these nanostructures. To realize the immense potential of these materials, it is necessary to maximize the coefficient. Therefore, the goal of this PhD thesis study was …

Privacy-Aware Security Applications In The Era Of Internet Of Things, Abbas Acar

FIU Electronic Theses and Dissertations

In this dissertation, we introduce several novel privacy-aware security applications. We split these contributions into three main categories: First, to strengthen the current authentication mechanisms, we designed two novel privacy-aware alternative complementary authentication mechanisms, Continuous Authentication (CA) and Multi-factor Authentication (MFA). Our first system is Wearable-assisted Continuous Authentication (WACA), where we used the sensor data collected from a wrist-worn device to authenticate users continuously. Then, we improved WACA by integrating a noise-tolerant template matching technique called NTT-Sec to make it privacy-aware as the collected data can be sensitive. We also designed a novel, lightweight, Privacy-aware Continuous Authentication (PACA) protocol. PACA …

Detection Of Human Vigilance State During Locomotion Using Wearable Fnirs, Masudur R. Siddiquee

FIU Electronic Theses and Dissertations

Human vigilance is a cognitive function that requires sustained attention toward change in the environment. Human vigilance detection is a widely investigated topic which can be accomplished by various approaches. Most studies have focused on stationary vigilance detection due to the high effect of interference such as motion artifacts which are prominent in common movements such as walking. Functional Near-Infrared Spectroscopy is a preferred modality in vigilance detection due to the safe nature, the low cost and ease of implementation. fNIRS is not immune to motion artifact interference, and therefore human vigilance detection performance would be severely degraded when studied …

Towards In-Situ Based Printed Sensor Systems For Real-Time Soil-Root Nutrient Monitoring And Prediction With Polynomial Regression, Lamar K. Burton

FIU Electronic Theses and Dissertations

This dissertation explores how to increase sensor density in the agricultural framework using low-cost sensors, while also managing major bottlenecks preventing their full commercial adoption for agriculture, accuracy and drift. It also investigated whether low-cost biodegradable printed sensor sheets can result in improved stability, accuracy or drift for use in precision agriculture. In this dissertation, multiple electrode systems were investigated with much of the work focused on printed carbon graphene electrodes (with and without nanoparticles). The sensors were used in two configurations: 1) in varying soil to understand sensor degradation and the effect of environment on sensors, and 2) in …

Development Of Gaussian Learning Algorithms For Early Detection Of Alzheimer's Disease, Chen Fang

FIU Electronic Theses and Dissertations

Alzheimer’s disease (AD) is the most common form of dementia affecting 10% of the population over the age of 65 and the growing costs in managing AD are estimated to be $259 billion, according to data reported in the 2017 by the Alzheimer's Association. Moreover, with cognitive decline, daily life of the affected persons and their families are severely impacted. Taking advantage of the diagnosis of AD and its prodromal stage of mild cognitive impairment (MCI), an early treatment may help patients preserve the quality of life and slow the progression of the disease, even though the underlying disease cannot …

Enhanced Surface Electrical Neurostimulation (Esens): A Non-Invasive Platform For Peripheral Neuromodulation, Andres Eduardo Pena

FIU Electronic Theses and Dissertations

Electrical stimulation of peripheral afferents has been used to study the sensory neural code and restore lost sensory function after amputation. Recently, implantable neural interfaces have prompted multiple breakthroughs in artificial somatosensory feedback for individuals with amputation, resulting in functional and psychological benefits. Although promising, the invasive nature of these approaches limits wide clinical applications, hindering the development of advanced neuromodulation strategies for intuitive sensory feedback. Transcutaneous (surface) stimulation is a potential non-invasive alternative. However, traditional surface stimulation methods are hampered by inadequate electrode and stimulation parameter fitting, localized discomfort, poor selectivity, and limited percept modulation.

An enhanced surface electrical …

Machine Vision, Not Human Vision, Guided Compression Towards Low-Latency And Robust Deep Learning Systems, Zihao Liu

FIU Electronic Theses and Dissertations

Deep Neural Networks (DNNs) have been achieving extraordinary performance across many exciting real-world applications, including image classification, speech recognition, natural language processing, medical diagnosis, self-driving cars, drones, anomaly detection and recognition of voice commands. However, the de facto DNN technique in real life exposes to two critical issues:

First, the ever-increasing amounts of data generated from mobile devices, sensors, and the Internet of Things (IoT) challenge the performance of the DNN system. there lack efficient solutions to reduce the power-hungry data offloading and storage on terminal devices like edge sensors, especially in face of the stringent constraints on communication bandwidth, …

On-Device Security And Privacy Mechanisms For Resource-Limited Devices: A Bottom-Up Approach, Leonardo Babun

FIU Electronic Theses and Dissertations

This doctoral dissertation introduces novel mechanisms to provide on-device security and privacy for resource-limited smart devices and their applications. These mechanisms aim to cover five fundamental contributions in the emerging Cyber-Physical Systems (CPS), Internet of Things (IoT), and Industrial IoT (IIoT) fields. First, we present a host-based fingerprinting solution for device identification that is complementary to other security services like device authentication and access control. Then, we design a kernel- and user-level detection framework that aims to discover compromised resource-limited devices based on behavioral analysis. Further we apply dynamic analysis of smart devices’ applications to uncover security and privacy risks …

Novel Passive Rfid Temperature Sensors Using Liquid Crystal Elastomers, Yousuf Shafiq

FIU Electronic Theses and Dissertations

When transporting perishable foods in the Cold Supply Chain (CSC), it is essential that they are maintained in a controlled temperature environment (typically from -1° to 10°C) to minimize spoilage. Fresh-food products, such as, meats, fruits, and vegetables, experience discoloration and loss of nutrients when exposed to high-temperatures. Also, medicines, such as, insulin and vaccines, can lose potency if they are not maintained at the appropriate temperatures. Consequently, the CSC is critical to the growth of global trade and to the worldwide availability of food and health supplies; especially, when considering that the retail food market consists mostly (approximately 65%) …

Artificial Intelligent Based Energy And Demand Side Management For Microgrids And Smart Homes Considering Customer Privacy, Ahmed F. Ebrahim

FIU Electronic Theses and Dissertations

The rapid development of various power electronics applications facilitates the integration of many smart grid applications in recent years. However, integration of intermittent renewable energy sources, highly stochastic electric vehicles (EVs) activities on the grid and time-varying smart loads have increased the level of grid vulnerability to unusual and high complexity and quality-related problems. Among these problems is to accurately estimate the real contribution and consumption of household loads, in the era of smart appliances and interoperability operation, and its relative impact to the grid’s operation. Specifically, household loads represent a significant percentage of electrical energy consumption and, therefore, could …

Towards Uav Assisted 5g Public Safety Network, Abhaykumar Kumbhar

FIU Electronic Theses and Dissertations

Ensuring ubiquitous mission-critical public safety communications (PSC) to all the first responders in the public safety network is crucial at an emergency site. The first responders heavily rely on mission-critical PSC to save lives, property, and national infrastructure during a natural or human-made emergency. The recent advancements in LTE/LTE-Advanced/5G mobile technologies supported by unmanned aerial vehicles (UAV) have great potential to revolutionize PSC.

However, limited spectrum allocation for LTE-based PSC demands improved channel capacity and spectral efficiency. An additional challenge in designing an LTE-based PSC network is achieving at least 95% coverage of the geographical area and human population with …