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 …

Bioscaffold Valve With And Without Mechanically Conditioned Stem Cells For The Treatment Of Critical Mitral Valve Diseases In The Young, Brittany A. Gonzalez

FIU Electronic Theses and Dissertations

Congenital heart disease, which includes heart valve defects, are the most common type of birth abnormality in the US. Infants with critical congenital valve disease have no established treatment-measure other than compassionate care options, owing to an absence of prosthetic valves in small sizes and their inability to support somatic growth. A regenerable valve would be appealing since these barriers could be overcome; it can potentially provide for growth, self-repair, infection resistance and be a permanent approach for replacing defective heart valves.

Porcine small intestinal submucosa (PSIS) bioscaffold was used to create valvular constructs with the possibility to grow overtime. …

Strategies To Identify And Mitigate Secondary Crashes In Real-Time, Angela Kitali

FIU Electronic Theses and Dissertations

Traffic incidents are the primary source of non-recurring congestion. In addition to affecting roadway operations, traffic congestion resulting from an incident exposes other vehicles to the risk of being involved in additional incidents, typically referred to as secondary crashes. Secondary crashes adversely affect traffic operations and impose risk on the safety of both road users and incident responders. Transportation agencies have been looking for ways to mitigate secondary crashes. However, secondary crash mitigation has several challenges. The length of the queue caused by an initial incident and the amount of time this queue lasts on the road varies, depending on …

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 …

Data Analytic Approach To Support The Activation Of Special Signal Timing Plans In Response To Congestion, Mosammat Tahnin Tariq

FIU Electronic Theses and Dissertations

Improving arterial network performance has become a major challenge that is significantly influenced by signal timing control. In recent years, transportation agencies have begun focusing on Active Arterial Management Program (AAM) strategies to manage the performance of arterial streets under the flagship of Transportation Systems Management & Operations (TSM&O) initiatives. The activation of special traffic signal plans during non-recurrent events is an essential component of AAM and can provide significant benefits in managing congestion.

Events such as surges in demands or lane blockages can create queue spillbacks, even during off-peak periods resulting in delays and spillbacks to upstream intersections. To …

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 …

Geographic Data Mining And Knowledge Discovery, Liangdong Deng

FIU Electronic Theses and Dissertations

Geographic data are information associated with a location on the surface of the Earth. They comprise spatial attributes (latitude, longitude, and altitude) and non-spatial attributes (facts related to a location). Traditionally, Physical Geography datasets were considered to be more valuable, thus attracted most research interest. But with the advancements in remote sensing technologies and widespread use of GPS enabled cellphones and IoT (Internet of Things) devices, recent years witnessed explosive growth in the amount of available Human Geography datasets. However, methods and tools that are capable of analyzing and modeling these datasets are very limited. This is because Human Geography …

Numerical Modeling And Conjugate Heat Transfer Analysis Of Single U-Tube Vertical Borehole Heat Exchangers, Talha Khan

FIU Electronic Theses and Dissertations

The primary purpose of this thesis was to develop a design for improving the efficiency of the vertical type single u-tube borehole heat exchanger. A thorough literature review of the various existing analytical and numerical models of the borehole heat exchanger (BHEs) was performed and numerical modeling of the BHE was conducted to solve the conjugate heat transfer problem in the BHE in 3D using ANSYS Fluent 2019 R1. A comparison between the results obtained using various mesh sizes, types, different turbulence models showed the independence of the parameters on the numerical simulation results.

From the numerical simulation, it was …

A Structural Equation Model Analysis Of Computing Identity Sub-Constructs And Student Academic Persistence, Mohsen Taheri

FIU Electronic Theses and Dissertations

This dissertation explores the impact of computing identity sub-constructs on the academic persistence of computing students. This research provides models, quantified relationships, and insights to increase the number of graduates with the intention of pursuing a career in computing. Despite the growing significance of computer science and all the projected new jobs in computer science, many university and college programs suffer from low student persistence rates. One theoretical framework used to better understand persistence in other STEM disciplines is disciplinary identity. Disciplinary identity refers to how students see themselves with respect to a discipline. This study examines the effects of …

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 …

Organic-Inorganic Halide Perovskite Nanocrystals And Solar Cells, Rui Guo

FIU Electronic Theses and Dissertations

A great challenge facing humanity in the 21^st century is finding inexhaustible and inexpensive energy sources to power the planet. Renewable energies are the best solutions because of their abundance, diversity, and pollution-free emission. Solar energy is the cleanest and most abundant renewable energy source available. In the continuing quest for efficient and low-cost solar cells, perovskite solar cells (PSCs) have emerged as a potential replacement for silicon solar cells. Since 2009, the record efficiencies of PSCs have been skyrocketing from 3.8 % to 25.2 % and are now approaching the theoretical limit. Along with the three-dimensional perovskites used …

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 …

Surface Enhanced Raman Spectroscopy (Sers) As A Nanoscale Adsorption Phenomenon: Development Of Tailored Nanomaterials For Applications In Drug Detection, Chiara Deriu

FIU Electronic Theses and Dissertations

Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique in which nanostructured substrates amplify the inherently weak Raman signal of an adsorbed species by several orders of magnitude, enabling the detection of trace compounds, up to the single molecule level. While this may be an exceptional tool for any analytical scientist, SERS is at present relegated to the role of academic sensation, and is underutilized in everyday analytical practice. The SERS community is increasingly attributing this setback to a poor understanding of nanoscale surfaces and their chemical environment; since molecular adsorption at the nanostructured surface enables SERS detection, uncertainty about …

Understanding Event Structure In Text, Mohammed Aldawsari

FIU Electronic Theses and Dissertations

Stories often appear in textual form, for example, news stories are found in the form of newspaper articles, blogs, or broadcast transcripts, and so forth. These contain descriptions of current, past, or future events. Automatically extracting knowledge from these events descriptions is an important natural language processing (NLP) task, and understanding event structure aids in this knowledge extraction. Event structure is the fact that events may have relationships or internal structure, for example, be in a co-reference relationship with another event mention, or composed of subevents.

Understanding event structure has received less attention in NLP than is due. This work …

Unifying Assessments Of Sustainability And Resilience In Civil Infrastructure Systems: The Case Of Masonry Structures, Samir J. Pandey

FIU Electronic Theses and Dissertations

Review of existing literature on the unification of sustainability and resilience showed the lack of a single effective framework that can unify the two, especially for building systems. Along this line of research, this study contributes a novel experimental framework to assess masonry structures and support a unified approach. This study performed structural analysis for resilience assessment and energy simulation for sustainability assessment. Based on the openings available in masonry walls, the study observed the changes in sustainability indicators (electricity consumption). Changes in resilience indicators (story drifts) were also observed. Results indicate that overall sustainability is compromised with additional openings …

Characterization Of Aortic Valve Interstitial Cells Responsible For Elastogenesis, Sana Nasim

FIU Electronic Theses and Dissertations

The aortic valve (AoV) controls unidirectional blood distribution from the left ventricle of the heart to the aorta for systemic circulation. During the systolic and diastolic phases, AoV leaflets rely on a precise extracellular matrix (ECM) microarchitecture for appropriate biomechanical performance based on the arrangement of collagen, elastin, and glycosaminoglycans. The ECM structure is generated and maintained by valvular interstitial cells (VICs), which reside within the leaflets. VICs are a heterogeneous population of cells that are derived from a mixture of developmental precursors. Mainly, VICs arise from endocardial and neural crest cells that migrate into the cardiac cushions during development. …

Interactive Virtual Training: Implementation For Early Career Teachers To Practice Classroom Behavior Management, Alban Delamarre

FIU Electronic Theses and Dissertations

Teachers that are equipped with the skills to manage and prevent disruptive behaviors increase the potential for their students to achieve academically and socially. Student success increases when prevention strategies and effective classroom behavior management (CBM) are implemented in the classroom. However, teachers with less than 5 years of experience, early career teachers (ECTs), are ill equipped to handle disruptive students. ECTs describe disruptive behaviors as a major factor for stress given their limited training in CBM. As a result, disruptive behaviors are reported by ECTs as one of the main reasons for leaving the field.

Virtual training environments (VTEs) …

Aeroelastic Testing To Evaluate Wind Effects On Transmission Systems, Ziad Azzi

FIU Electronic Theses and Dissertations

The transmission infrastructure in the U.S. faces substantial risk from hurricanes. Wind-induced damage poses an immense threat to the electric power grid; such hazards have significantly impacted the supply, generation, and delivery of power to large portions of the U.S. in the past. When exposed to strong winds, critical demands in several elements in transmission tower-line systems may exceed corresponding capacities and trigger various modes of failure. Enhancing the resilience of the transmission grid against increasing threats from hurricanes and strong winds is therefore of critical importance. The results of 1:50 aeroelastic scaled models of a self-supported steel lattice tower …

Work Zone Safety Analysis, Investigating Benefits From Accelerated Bridge Construction (Abc) On Roadway Safety, Seyedmirsajad Mokhtarimousavi

FIU Electronic Theses and Dissertations

The attributes of work zones have significant impacts on the risk of crash occurrence. Therefore, identifying the factors associated with crash severity and frequency in work zone locations is of important value to roadway safety. In addition, the significant loss of workers’ lives and injuries resulting from work zone crashes indicates the emergent need for a comprehensive and in-depth investigation of work zone crash mechanisms.

The cost of work zone crashes is another issue that should be taken into account as work zone crashes impose millions of dollars on society each year. Applying innovative construction methods like Accelerated Bridge Construction …

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 …

A Deep-Learning Based Robust Framework Against Adversarial P.E. And Cryptojacking Malware, Faraz Amjad Naseem

FIU Electronic Theses and Dissertations

This graduate thesis introduces novel, deep-learning based frameworks that are resilient to adversarial P.E. and cryptojacking malware. We propose a method that uses a convolutional neural network (CNN) to classify image representations of malware, that provides robustness against numerous adversarial attacks. Our evaluation concludes that the image-based malware classifier is significantly more robust to adversarial attacks than a state-of-the-art ML-based malware classifier, and remarkably drops the evasion rate of adversarial samples to 0% in certain attacks. Further, we develop MINOS, a novel, lightweight cryptojacking detection system that accurately detects the presence of unwarranted mining activity in real-time. MINOS can detect …

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 …

A Comprehensive Analysis Of Balance, Symmetry, And Center Of Mass In The Gait Cycle Of Transfemoral Amputees, Kayla T. Etienne

FIU Electronic Theses and Dissertations

The purpose of this thesis is to create a framework that assists in the transfemoral prosthesis fitting process by calculating balance and symmetry to quantify patient comfort with an understanding of bipedal locomotion and human anatomy. Three different software applications were used to compare (1) the body position during gait cycle, (2) the natural and amputee anatomies, (3) the natural and prosthetic legs, and (4) the equilibrium and torque movements of the hip, knee, and ankle joints. Models were created in Maya for analysis in Solidworks and MEL code evaluation with MatLab. The MatLab code tested combinations of joint degrees …

Modeling And Analyzing Cyber-Physical Systems Using Hybrid Predicate Transition Nets, Dewan Mohammad Moksedul Alam

FIU Electronic Theses and Dissertations

Cyber-Physical Systems (CPSs) are software controlled physical devices that are being used everywhere from utility features in household devices to safety-critical features in cars, trains, aircraft, robots, smart healthcare devices. CPSs have complex hybrid behaviors combining discrete states and continuous states capturing physical laws. Developing reliable CPSs are extremely difficult. Formal modeling methods are especially useful for abstracting and understanding complex systems and detecting and preventing early system design problems. To ensure the dependability of formal models, various analysis techniques, including simulation and reachability analysis, have been proposed in recent decades. This thesis aims to provide a unified formal modeling …