Engineering Commons^™

A Simplified Secure Programming Platform For Internet Of Things Devices, Halim Burak Yesilyurt

FIU Electronic Theses and Dissertations

The emerging Internet of Things (IoT) revolution has introduced many useful applications that are utilized in our daily lives. Users can program these devices in order to develop their own IoT applications; however, the platforms and languages that are used during development are abounding, complicated, and time-consuming. The software solution provided in this thesis, PROVIZ+, is a secure sensor application development software suite that helps users create sophisticated and secure IoT applications with little software and hardware experience. Moreover, a simple and efficient domain-specific programming language, namely Panther language, was designed for IoT application development to unify existing programming languages. …

The Oscillatory Shear Index: Quantifications For Valve Tissue Engineering And A Novel Interpretation For Calcification, Alex Williams

FIU Electronic Theses and Dissertations

Heart valve tissue engineering (HVTE) stands as a potential intervention that could reduce the prevalence of congenital heart valve disease in juvenile patients. Prior studies in our laboratory have utilized mechanobiological testing to quantify the forces involved in the development of heart valve tissue, utilizing a Flow-Stretch-Flexure (FSF) bioreactor to condition bone marrow stem cells (BMSCs)-derived valve tissue. Simulations have demonstrated that certain sets of flow conditions can introduce specific levels of oscillatory shear stress (OSS)-induced stimuli, augmenting the growth of engineered valves as well as influencing collagen formation, extracellular matrix (ECM) composition and gene expression. The computational findings discussed …

Low Cost Scanning Arrays, Matilda Gabriela Livadaru

FIU Electronic Theses and Dissertations

Over the past decades, phased arrays have played a significant role in the development of modern radar and communication systems. The availability of printed circuit technology and ease of integration with microwave components, as well as the development of low profile and low weight approaches, have also played an important role in their conformal adaptation. However, fabrication costs remain prohibitive for many emergent platforms, including 5G base stations and autonomous vehicles, when compared to a conventional mechanically steered passive array. Therefore, cost reductions in the fabrication and integration of modern phased arrays are essential to their adaptation for many upcoming …

Study On Strut And Node Behavior In Strut-And-Tie Modeling, Nazanin Rezaei

FIU Electronic Theses and Dissertations

The strut-and-tie method (STM) is a simple and conservative method for designing concrete structures, especially deep beams. This method expresses complicated stress patterns as a simple truss or kinematic model made up of compression elements (struts), tension elements (ties), and the joints between elements (nodes). STM is based on lowerbound plasticity theorem, so using it properly will lead to a conservative design. Although the concepts of STM have been around in concrete design since the late 19th century, STM was first introduced in AASHTO LRFD in 1994 and ACI 318-02 in 2002. ACI 318 defines two different types of struts …

Novel Structural Health Monitoring And Damage Detection Approaches For Composite And Metallic Structures, Shervin Tashakori

FIU Electronic Theses and Dissertations

Mechanical durability of the structures should be continuously monitored during their operation. Structural health monitoring (SHM) techniques are typically used for gathering the information which can be used for evaluating the current condition of a structure regarding the existence, location, and severity of the damage. Damage can occur in a structure after long-term operating under service loads or due to incidents. By detection of these defects at the early stages of their growth and nucleation, it would be possible to not only improve the safety of the structure but also reduce the operating costs. The main goal of this dissertation …

Investigating Scale Effects On Analytical Methods Of Predicting Peak Wind Loads On Buildings, Mohammadtaghi Moravej

FIU Electronic Theses and Dissertations

Large-scale testing of low-rise buildings or components of tall buildings is essential as it provides more representative information about the realistic wind effects than the typical small scale studies, but as the model size increases, relatively less large-scale turbulence in the upcoming flow can be generated. This results in a turbulence power spectrum lacking low-frequency turbulence content. This deficiency is known to have significant effects on the estimated peak wind loads.

To overcome these limitations, the method of Partial Turbulence Simulation (PTS) has been developed recently in the FIU Wall of Wind lab to analytically compensate for the effects of …

Exploring Wireless Sensor Network Technology In Sustainable Okra Garden: A Comparative Analysis Of Okra Grown In Different Fertilizer Treatments, Lamar K. Burton, Yemererach Mekonnen, Arif I. Sarwat, Shekhar Bhansali, Krish Jayachandran

Electrical and Computer Engineering Faculty Publications

The goal of this project was to explore commercial agricultural and irrigation sensor kits and to discern if the commercial wireless sensor network (WSN) is a viable tool for providing accurate real-time farm data at the nexus of food energy and water. The smart garden consists of two different varieties of Abelmoschus esculentus (okra) planted in raised beds, each grown under two different fertilizer treatments. Soil watermark sensors were programed to evaluate soil moisture and dictate irrigation events up to four times a day, while soil temperature and photosynthetic solar radiation sensors also recorded data every six hours. Solar panels …

The Catalytic Performance Of Lithium Oxygen Battery Cathodes, Neha Chawla

FIU Electronic Theses and Dissertations

High energy density batteries have garnered much attention in recent years due to their demand in electric vehicles. Lithium-oxygen (Li-O2) batteries are becoming some of the most promising energy storage and conversion technologies due to their ultra-high energy density. They are still in the infancy stage of development and there are many challenges needing to be overcome before their practical commercial application. Some of these challenges include low round-trip efficiency, lower than theoretical capacity, and poor rechargeability. Most of these issued stem from the poor catalytic performance of the cathode that leads to a high overpotential of the battery. In …

Putting The Generic Solution Of Transparent Thinking Approach (Tta) In Instructional Material Production, Mohammad A. Aliedeh, Sajedah Aliedeh

ICOT 18 - International Conference on Thinking - Cultivating Mindsets for Global Citizens

Humanity is overburdened by an overwhelming challenges, problems and failures that are plaguing global development system, in general, and global educational system in specific. Transparent Thinking Approach (TTA) is developed in response to these multi scale and multi domain problems by offering a generic reform approach that enable the thinker to employ a multi perspective, maneuvering, and modeling tools while looking for a solution. TTA is a newly developed value-engrained and thinking based educational reform approach. It is generic and unique features enables it to easily diffuse in all domains (Aliedeh, M. A., 2015 a, b, c, 2016, …

“Un Poder Transformador”. Creatividad Y Habilidades De Pensamiento Que Nutren La Experimentación De Nuevas Ideas Sustentables”, Vanesa Abadie A. Abadie

ICOT 18 - International Conference on Thinking - Cultivating Mindsets for Global Citizens

Si partimos de preguntas tales como: ¿Qué vale la pena enseñar?, ¿Cómo las habilidades de pensamiento promueven prácticas que conducen a la sostenibilidad ambiental y la revitalización?, ¿Cómo promovemos el desarrollo de habilidades de pensamiento que conduzcan al uso del conocimiento, la tecnología y la innovación para promover la sostenibilidad y la revitalización?

Como docentes debemos introducir desafíos en contextos adecuados para así generar en los alumnos nuevas ideas. Tanto la creatividad como el pensamiento crítico son procesos que se nutren con la experimentación de ideas. Ellas pueden surgir a través de una acción, un relato, una imagen, un tópico …

Poly (Ionic Liquid) Based Electrolyte For Lithium Battery Application, Meer N. Safa

FIU Electronic Theses and Dissertations

The demand for electric vehicles is increasing rapidly as the world is preparing for a fossil fuel-free future in the automotive field. Lithium battery technologies are the most effective options to replace fossil fuels due to their higher energy densities. However, safety remains a major concern in using lithium as the anode, and the development of non-volatile, non-flammable, high conductivity electrolytes is of great importance. In this dissertation, a gel polymer electrolyte (GPE) consisting of ionic liquid, lithium salt, and a polymer has been developed for their application in lithium batteries. A comparative study between GPE and ionic liquid electrolyte …

Thermodynamic Evaluation And Modeling Of Grade 91 Alloy And Its Secondary Phases Through Calphad Approach, Andrew Logan Smith Mr.

FIU Electronic Theses and Dissertations

Grade 91 (Gr.91) is a common structural material used in boiler applications and is favored due to its high temperature creep strength and oxidation resistance. Under cyclic stresses, the material will experience creep deformation eventually causing the propagation of type IV cracks within its heat-affected-zone (HAZ) which can be a major problem under short-term and long-term applications. In this study, we aim to improve this premature failure by performing a computational thermodynamic study through the Calculation of Phase Diagram (CALPHAD) approach. Under this approach, we have provided a baseline study as well as simulations based on additional alloying elements such …

On-Line Condition Monitoring, Fault Detection And Diagnosis In Electrical Machines And Power Electronic Converters, Alberto Berzoy

FIU Electronic Theses and Dissertations

The objective of this PhD research is to develop robust, and non-intrusive condition monitoring methods for induction motors fed by closed-loop inverters. The flexible energy forms synthesized by these connected power electronic converters greatly enhance the performance and expand the operating region of induction motors. They also significantly alter the fault behavior of these electric machines and complicate the fault detection and protection. The current state of the art in condition monitoring of power-converter-fed electric machines is underdeveloped as compared to the maturing condition monitoring techniques for grid-connected electric machines.

This dissertation first investigates the stator turn-to-turn fault modelling for …

A Dynamical System Approach For Resource-Constrained Mobile Robotics, Tauhidul Alam

FIU Electronic Theses and Dissertations

The revolution of autonomous vehicles has led to the development of robots with abundant sensors, actuators with many degrees of freedom, high-performance computing capabilities, and high-speed communication devices. These robots use a large volume of information from sensors to solve diverse problems. However, this usually leads to a significant modeling burden as well as excessive cost and computational requirements. Furthermore, in some scenarios, sophisticated sensors may not work precisely, the real-time processing power of a robot may be inadequate, the communication among robots may be impeded by natural or adversarial conditions, or the actuation control in a robot may be …

Synthesis & Fundamental Formation Mechanism Study Of High Temperature & Ultrahigh Temperature Ceramics, Paniz Foroughi

FIU Electronic Theses and Dissertations

Borides and carbides of tantalum and hafnium are of great interest due to their ultrahigh temperature applications. Properties of these ceramics including oxidation resistance and mechanical properties might be further improved through solid solution/composite formation. Synthesis of single-phase Ta_xHf_1-xC and Ta_xHf_1-xB₂ solid solution powders including nanopowders via carbothermal reduction (CTR) is complicated due to noticeable difference in reactivity of parent oxides with carbon, and also the low solubility of those oxides in each other. Moreover, for TaC-HfC system the solid solution may go through phase separation due to the presence of …

User-Centric Privacy Preservation In Mobile And Location-Aware Applications, Mingming Guo

FIU Electronic Theses and Dissertations

The mobile and wireless community has brought a significant growth of location-aware devices including smart phones, connected vehicles and IoT devices. The combination of location-aware sensing, data processing and wireless communication in these devices leads to the rapid development of mobile and location-aware applications. Meanwhile, user privacy is becoming an indispensable concern. These mobile and location-aware applications, which collect data from mobile sensors carried by users or vehicles, return valuable data collection services (e.g., health condition monitoring, traffic monitoring, and natural disaster forecasting) in real time. The sequential spatial-temporal data queries sent by users provide their location trajectory information. The …

Synthesis, Processing, And Fundamental Phase Formation Study Of Czts Films For Solar Cell Applications, Osama Awadallah

FIU Electronic Theses and Dissertations

Copper zinc tin sulfide (Cu₂ZnSnS₄ or CZTS) kesterite compound has attracted much attention in the last years as a new abundant, low cost, and environmentally benign material with desirable optoelectronic properties for Photovoltaic (PV) thin film solar cell applications. Among various synthesis routes for CZTS thin films, sol-gel processing is one of the most attractive routes to obtain CZTS films with superior quality and low cost.

In this study, sol-gel sulfurization process parameters for CZTS thin films were systematically investigated to identify the proper process window. In addition, temperature dependent Raman spectroscopy was employed to monitor the …

Multimodal Imaging For Enhanced Diagnosis And For Assessing Progression Of Alzheimer’S Disease, Chunfei Li

FIU Electronic Theses and Dissertations

A neuroimaging feature extraction model is designed to extract region-based image features whose values are predicted by base learners trained on raw neuroimaging morphological variables. The main objectives are to identify Alzheimer’s disease (AD) in its earliest manifestations, and be able to predict and gauge progression of the disease through the stages of mild cognitive impairment (EMCI), late MCI (LMCI) and AD. The model was evaluated on the ADNI database and showed 75.26% accuracy for the challenging EMCI diagnosis based on the 10-fold cross-validation. Our approach also performed well for the other binary classifications: EMCI vs. LMCI (72.3%), EMCI vs. …

Reconfigurable Antennas Using Liquid Crystalline Elastomers, John Gibson

FIU Electronic Theses and Dissertations

This dissertation demonstrates the design of reversibly self-morphing novel liquid crystalline elastomer (LCE) antennas that can dynamically change electromagnetic performance in response to temperature. This change in performance can be achieved by programming the shape change of stimuli-responsive (i.e., temperature-responsive) LCEs, and using these materials as substrates for reconfigurable antennas. Existing reconfigurable antennas rely on external circuitry such as Micro-Electro-Mechanical-Systems (MEMS) switches, pin diodes, and shape memory alloys (SMAs) to reconfigure their performance. Antennas using MEMS or diodes exhibit low efficiency due to the losses from these components. Also, antennas based on SMAs can change their performance only once as …

Rethinking The I/O Stack For Persistent Memory, Mohammad Ataur Rahman Chowdhury

FIU Electronic Theses and Dissertations

Modern operating systems have been designed around the hypotheses that (a) memory is both byte-addressable and volatile and (b) storage is block addressable and persistent. The arrival of new Persistent Memory (PM) technologies, has made these assumptions obsolete. Despite much of the recent work in this space, the need for consistently sharing PM data across multiple applications remains an urgent, unsolved problem. Furthermore, the availability of simple yet powerful operating system support remains elusive.

In this dissertation, we propose and build The Region System – a high-performance operating system stack for PM that implements usable consistency and persistence for application …

Experimental Investigation Of Wind-Induced Response Of Span-Wire Traffic Signal Systems, Manuel A. Matus Mr.

FIU Electronic Theses and Dissertations

The purpose of this investigation was to identify key design parameters that might significantly affect the response of span wire traffic light systems during extreme wind events. The performance of these systems was assessed through physical testing in an effort to quantify the effect of sag ratio, wire tension and wire clearance. The Wall of Wind experimental facility at Florida International University was utilized for testing the systems at different wind speeds and wind directions.

The findings showed that, at all tested wind directions, lift, drag and tension forces increased with increasing wind speeds. On the contrary, increasing the wind …

Radar Signal Processing For Interference Mitigation, Zhe Geng

FIU Electronic Theses and Dissertations

It is necessary for radars to suppress interferences to near the noise level to achieve the best performance in target detection and measurements. In this dissertation work, innovative signal processing approaches are proposed to effectively mitigate two of the most common types of interferences: jammers and clutter. Two types of radar systems are considered for developing new signal processing algorithms: phased-array radar and multiple-input multiple-output (MIMO) radar. For phased-array radar, an innovative target-clutter feature-based recognition approach termed as Beam-Doppler Image Feature Recognition (BDIFR) is proposed to detect moving targets in inhomogeneous clutter. Moreover, a new ground moving target detection algorithm …

Energy Demand Response For High-Performance Computing Systems, Kishwar Ahmed

FIU Electronic Theses and Dissertations

The growing computational demand of scientific applications has greatly motivated the development of large-scale high-performance computing (HPC) systems in the past decade. To accommodate the increasing demand of applications, HPC systems have been going through dramatic architectural changes (e.g., introduction of many-core and multi-core systems, rapid growth of complex interconnection network for efficient communication between thousands of nodes), as well as significant increase in size (e.g., modern supercomputers consist of hundreds of thousands of nodes). With such changes in architecture and size, the energy consumption by these systems has increased significantly. With the advent of exascale supercomputers in the next …

Origami Antennas For Novel Reconfigurable Communication Systems, Xueli Liu

FIU Electronic Theses and Dissertations

Antennas play a crucial role in communication systems since they are the transmitting/receiving elements that transition information from guided transmission to open-space propagation. Antennas are used in many different applications such as aerospace communications, mobile phones, TVs and radios. Since the dimensions of antennas are usually physically proportional to the wavelength at their operating frequencies, it is important to develop large antennas and arrays that can be stowed compactly and easily deployed. Also, it is important to minimize the number of antennas on a platform by developing multifunctional antennas.

The first aim of this research is to develop new deployable, …

Memory-Aware Scheduling For Fixed Priority Hard Real-Time Computing Systems, Gustavo A. Chaparro-Baquero

FIU Electronic Theses and Dissertations

As a major component of a computing system, memory has been a key performance and power consumption bottleneck in computer system design. While processor speeds have been kept rising dramatically, the overall computing performance improvement of the entire system is limited by how fast the memory can feed instructions/data to processing units (i.e. so-called memory wall problem). The increasing transistor density and surging access demands from a rapidly growing number of processing cores also significantly elevated the power consumption of the memory system. In addition, the interference of memory access from different applications and processing cores significantly degrade the …

The Thermal-Constrained Real-Time Systems Design On Multi-Core Platforms -- An Analytical Approach, Shi Sha

FIU Electronic Theses and Dissertations

Over the past decades, the shrinking transistor size enabled more transistors to be integrated into an IC chip, to achieve higher and higher computing performances. However, the semiconductor industry is now reaching a saturation point of Moore’s Law largely due to soaring power consumption and heat dissipation, among other factors. High chip temperature not only significantly increases packing/cooling cost, degrades system performance and reliability, but also increases the energy consumption and even damages the chip permanently. Although designing 2D and even 3D multi-core processors helps to lower the power/thermal barrier for single-core architectures by exploring the thread/process level parallelism, the …

Novel Strongly Coupled Magnetic Resonant Systems, Daerhan Liu

FIU Electronic Theses and Dissertations

Wireless power transfer (WPT) technologies have become important for our everyday life. The most commonly used near-field WPT method is inductive coupling, which suffers from low efficiency and small range. The Strongly Coupled Magnetic Resonance (SCMR) method was developed recently, and it can be used to wirelessly transfer power with higher efficiency over a longer distance than the inductive coupling method.

This dissertation develops new SCMR systems that have better performance compared to standard SCMR systems. Specifically, two new 3-D SCMR systems are designed to improve the angular misalignment sensitivity of WPT systems. Their power transfer efficiency for different angular …

3d Multilevel Spin Transfer Torque Devices, J. Hong, M. Stone, Department Of Electrical And Computer Engineering, Florida International University, K. Luongo, Q. Zheng, Z. Yuan, K. Xia, N. Xu, L. You, Sakhrat Khizroev

Electrical and Computer Engineering Faculty Publications

Spin-transfer torque magnetic tunneling junction devices capable of a multilevel three-dimensional (3D) information processing are studied in the sub-20-nm size range. The devices are built using He⁺ and Ne⁺ focused ion beam etching. It has been demonstrated that due to their extreme scalability and energy efficiency, these devices can significantly reduce the device footprint compared to the modern CMOS approaches and add advanced features in a 3D stack with a sub-20-nm size using a spin polarized current.

Thermodynamic Investigation Of La0.8sr0.2mno3±Δ Cathode, Including The Prediction Of Defect Chemistry, Electrical Conductivity And Thermo-Mechanical Properties, Shadi Darvish

FIU Electronic Theses and Dissertations

Fundamental thermodynamic investigations have been carried out regarding the phase equilibria of La_0.8Sr_0.2MnO_3±δ (LSM), a cathode of a solid oxide fuel cell (SOFC), utilizing the CALculation of PHAse Diagram (CALPHAD) approach. The assessed thermodynamic databases developed for LSM perovskite in contact with YSZ fluorite and the other species have been discussed. The application of computational thermodynamics to the cathode is comprehensively explained in detail, including the defect chemistry analysis as well as the quantitative Brouwer diagrams, electronic conductivity, cathode/electrolyte interface stability, thermomechanical properties of the cathode and the impact of gas impurities, such as CO …

Plasmonic Nanoplatforms For Biochemical Sensing And Medical Applications, Arash Ahmadivand

FIU Electronic Theses and Dissertations

Plasmonics, the science of the excitation of surface plasmon polaritons (SPP) at the metal-dielectric interface under intense beam radiation, has been studied for its immense potential for developing numerous nanophotonic devices, optical circuits and lab-on-a-chip devices. The key feature, which makes the plasmonic structures promising is the ability to support strong resonances with different behaviors and tunable localized hotspots, excitable in a wide spectral range. Therefore, the fundamental understanding of light-matter interactions at subwavelength nanostructures and use of this understanding to tailor plasmonic nanostructures with the ability to sustain high-quality tunable resonant modes are essential toward the realization of highly …