Engineering Commons^™

Multiple Agent Target Tracking In Gps-Denied Environments, Skyler Tolman

Theses and Dissertations

Unmanned aerial systems (UAS) are effective for surveillance and monitoring, but struggle with persistent, long-term tracking, especially without GPS, due to limited flight time. Persistent tracking can be accomplished using multiple vehicles if one vehicle can effectively hand off the tracking information to another replacement vehicle. This work presents a solution to the moving-target handoff problem in the absence of GPS. The proposed solution (a) a nonlinear complementary filter for self-pose estimation using only an IMU, (b) a particle filter for relative pose estimation between UAS using a relative range (c) visual target tracking using a gimballed camera when the …

Analysis Of Applied Modifications To A Cone Penetration Test-Based Lateral Spread Displacement Prediction Model, Alexander Edward Corob

Theses and Dissertations

This study set out to examine the effectiveness and reliability of six modifications to the Zhang et al. (2004) CPT-based lateral spread model. A regression analysis, distribution charts, and a discriminant analysis are performed to determine how effective the modifications are on the model. From the comparisons and statistical analysis performed in this study, application of these modifications reduces over-predictions from strain-based prediction methods. Unfortunately, the tendency to under-predict displacements on average is also increased.

Bending Behavior Of Concrete Beams With Fiber/Epoxy Composite Rebar, Kolten Dewayne Rice

Theses and Dissertations

This research explores the use of carbon/epoxy and fiberglass/epoxy fiber-reinforced polymer (FRP) composite rebar manufactured on a three-dimensional braiding machine for use as reinforcement in concrete beams under four-point bending loads. Multiple tows of prepreg composite fibers were pulled to form a unidirectional core. The core was consolidated with spirally wound Kevlar fibers which were designed to also act as ribs to increase pullout strength. The rebar was cured at 121â—¦C (250â—¦F) in an inline oven while keeping tension on the fibers. Five configurations of reinforcing bars were used in this study as reinforcement in concrete beam specimens: carbon/epoxy rebar …

Characterization And Modeling Of The Martensite Transformation In Advanced High-Strength Steels, Stephen Roy Cluff

Theses and Dissertations

Multiple studies on the microstructures of advanced high-strength steels are presented here that seek to add to the already substantial body of knowledge on martensite in steel. These studies seek to gain additional insight into the role that the martensite transformation has on the observed mechanical properties of modern steels. Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lath Martensitic Steel The study of post-transformation microstructures and their properties can be greatly enhanced by studying their dependence on the grain boundary content of parent microstructures. Recent work has extended the crystallographic reconstruction of parent austenite in steels to include …

Machine Learning On Acoustic Signals Applied To High-Speed Bridge Deck Defect Detection, Yao Chou

Theses and Dissertations

Machine learning techniques are being applied to many data-intensive problems because they can accurately provide classification of complex data using appropriate training. Often, the performance of machine learning can exceed the performance of traditional techniques because machine learning can take advantage of higher dimensionality than traditional algorithms. In this work, acoustic data sets taken using a rapid scanning technique on concrete bridge decks provided an opportunity to both apply machine learning algorithms to improve detection performance and also to investigate the ways that training of neural networks can be aided by data augmentation approaches. Early detection and repair can enhance …

An Exploration Of Neural Networks In Enhanced Resolution Remote Sensing Products, Jordan Paul Brown

Theses and Dissertations

Scatterometry and radiometry are used to obtain measurements of Earth properties with extensive spatial coverage at daily or near-daily temporal resolution. Their measurements are used in many climate studies and weather applications, such as iceberg tracking, ocean wind estimation, and volumetric soil moisture measurements. The spatial resolution of these data products ranges from a few kilometers to tens of kilometers. Techniques to enhance the spatial resolution of these products help reveal finer scale features, but come at the cost of increased noise. This thesis explores the application of neural networks as a possible method to handle the noise and uncertainty …

Near-Coastal Ultrahigh Resolution Scatterometer Winds, Nolan Lawrence Hutchings

Theses and Dissertations

RapidScat 2.5 km ultrahigh resolution (UHR) wind estimation is introduced and validated it in near-coastal regions. In addition, this thesis applies direction interval retrieval techniques and develops a new wind processing method to enhance the performance of RapidScat UHR wind estimation in the nadir region. The new algorithm is validated with L2B wind estimates, Numerical Weather Prediction (NWP) wind products, and buoy measurements. The wind processing improvements produce more spatially consistent UHR winds that compare well with the wind products mentioned above. Hawaii regional climate model (HRCM), QuikSCAT, and ASCAT wind estimates are compared in the lee of the Big …

Vertical Electrical Impedance Measurements Of Concrete Bridge Decks, Jared Scott Baxter

Theses and Dissertations

This research focuses on the creation, validation, automation, and deployment of a nondestructive vertical electrical impedance (VEI) bridge deck assessment apparatus. A multichannel impedance analyzer with a moving platform is developed that can assess the deterioration state of a bridge deck without stationary traffic control. The multichannel apparatus is capable of taking over 500 impedance samples a second and can scan a bridge deck over 500 times faster than more traditional techniques. This research also shows VEI measurements are inversely proportional to the diffusivity of ions through concrete and that an impedance measurement frequency of 25 kHz is the most …

Scatterometer Cross Calibration Using Volume Scattering Models For Amazon Rainforest Canopies, Evan Neil Chrisney

Theses and Dissertations

Spaceborne scatterometers have measured the normalized radar cross section (RCS) of the earth's surface for several decades. Two frequencies, C- and Ku-band, have been used in designing scatterometers, such as with the Ku-band NASA Scatterometer (NSCAT) and the C-band Advanced Scatterometer (ASCAT). The scatterometer data record between C- and Ku-band has been disjoint for several decades due to the difficulties in cross calibration of sensors that operate at different frequencies and incidence angles. A model for volume scattering over the Amazon rainforest canopy that includes both the incidence angle and frequency dependence is developed to overcome this challenge in cross …

Pilot-Scale Test Of Water Wash Carbon Dioxide Absorption System For Purifying Landfill Gas At Jones Island Wastewater Reclamation Facility, Rebecca Schruender

Theses and Dissertations

Biogas, a product of the digestion of organic material, consists primarily of methane and carbon dioxide. By purifying raw biogas, or removing the carbon dioxide, it can be upgraded to biomethane, which can be used to generate heat and electricity or as a substitute for natural gas. An effective method of biogas purification is the water wash process, which consists of an absorption column in which a stream of biogas runs counter-current to a stream of water. The carbon dioxide dissolves in the water, increasing the methane concentration of the gas. A pilot scale system was operated at Jones Island …

Trajectory Optimization And Design For A Large Number Of Unmanned Aerial Vehicles, Jenna Elisabeth Newcomb

Theses and Dissertations

An unmanned aerial vehicle (UAV) swarm allows for a more time-efficient method of searching a specified area than a single UAV or piloted plane. There are a variety of factors that affect how well an area is surveyed. We specifically analyzed the effect both vehicle properties and communication had on the swarm search performance. We used non-dimensionalization so the results can be applied to any domain size with any type of vehicle. We found that endurance was the most important factor. Vehicles with good endurance sensed approximately 90% to 100% of the grid, even when other properties were lacking. If …

A Game Modeling Of A Closed-Loop Supply Chain In A Water-Energy Nexus: Technology Advancement, Market Competition And Capacity Limit, Nabeel Hamoud

Theses and Dissertations

Water and energy are two scarce and concerning resources interconnected in the water-energy nexus. In the nexus, production of energy needs water, and production of water needs energy. For better management of these resources in the nexus, this research considers a supply chain that consists of water suppliers, power suppliers, and consumers of these commodities. In the chain, water suppliers purchase power from power suppliers, and power suppliers purchase water from water suppliers. Other consumers can also buy these resources at the water and power markets. Each firm tries to maximize its own profit. The suppliers of water and power …

Underwater Particle Image Velocimetry (Piv) Measurement Of Turbulence Over Mussel Bed In A Deepsite Of Lake Michigan, Tong Jin

Theses and Dissertations

The influence of the benthic filter feeders, such as bivalves, on ecosystem plankton, and nutrient dynamics is considered significant in shallow marine and freshwater systems. Recent indirect evidence showed that the profundal quagga mussels (Dreissena rostriformis bugensis) have fundamentally altered energy flow and dynamics of nutrients and phytoplankton in Lake Michigan and other Great Lakes. To investigate the phytoplankton grazing rate of the quagga mussel and the mussel siphon currents induced bio-mixing, a self-contained in situ Underwater Particle Image Velocimetry was developed to measure the turbulence structure and the turbulent diffusion coefficient immediately above the profundal quagga mussel covered substrate …

Application Of Survival Analysis Techniques To Probabilistic Assessment Of Fatigue In Steel Bridges, Azam Nabizadehdarabi

Theses and Dissertations

The fatigue of engineering materials under repetitive loading is a significant issue affecting the design and durability of components and systems in a variety of engineering-related applications including civil, mechanical, aerospace, automotive, and electronics. Many factors can affect the service life of a component or system under repetitive loading, such as the type of structure, loading, connection details, stress state, peak stress or stress range, surface condition, temperature, and environmental exposure. Currently, there is no comprehensive probabilistic approach that can systematically address all the factors that contribute to fatigue on a single mathematical platform. However, advanced analysis techniques developed for …

A Systematic Approach For Automatically Answering General-Purpose Objective And Subjective Questions, Lok Prasad Acharya

Theses and Dissertations

In this era of information explosion, people generally rely on the Internet, and more precisely, the search engines to get answers to their questions. However, what a search engine can do is just retrieve documents. Given some keywords, it only returns the relevant ranked documents that contain the keywords. Although users often want a precise answer to a question, they are left to extract answers from the documents themselves. This is where Automatic Question Answering (AQA) systems come into play. An AQA system takes questions in natural language as input and searches related answers in the set of documents and …

Effects Of Resampled Data On Time Series Forecasting Accuracy, Jennifer Garland

Theses and Dissertations

This thesis will look at time series forecasting of the air pollutants in Beijing, China and the power consumption of an individual household located in Sceaux, France. The forecast will be taken from two classical methods, the Holt-Winters’ methods and the Seasonal Autoregressive Integrated Moving Average (SARIMA) method. The Holt-Winters’ method will be looked at from the additive, multiplicative and damped methods. The SARIMA model will be looked at as a uni-variate model. In this thesis, it will be shown that less complex algorithms, such as the Holt-Winters’ methods can process larger data sets without the need of resampling, and …

Improving Grapheme-To-Phoneme Translation With The Use Of Nalu Attention Mechanisms, Brian Sheldon Smith

Theses and Dissertations

In recent years, Natural Language Processing in the field of machine learning has seen some major improvements. Data scientists have shown that neural networks are capable of breaking down semantics of sentences, translating languages, and answering complex questions with fast recall. While impressive, these feats all hinge on having access to a massive amount of clean text, or data sets with almost perfect grammar and spelling. Without this, neural networks will usually fail to converge on a meaningful result. To partially this dependency, Grapheme-to-Phoneme conversion can be employed. This is the conversion of words from their spellings to a form …

Deep Learning Models For Visibility Forecasting, Luz Carolina Ortega Gomez

Theses and Dissertations

This dissertation addresses the task of visibility forecasting via deep learning models using data from weather stations. Visibility is one of the most critical weather impacts on transportation systems. Low visibility conditions can seriously impact safety and traffic operations, leading to adverse scenarios, causing accidents, and jeopardizing transportation systems. Accurate visibility forecasting plays a key role in decision-making and management of transportation systems. However, due to the complexity and variability of weather variables, visibility forecasting remains a highly challenging task and a matter of significant interest for transportation agencies nationwide. This dissertation explores the use of deep learning models for …

An Application Of Clustering And Cluster Update Methods To Boiler Sensor Prediction And Case-Based-Reasoning To Boiler Repair, Timothy Edward Rooney

Theses and Dissertations

Driven by demand from both consumers and manufacturers alike, Internet of Things (IoT)

capabilities are being built into more products. Consumers want more control and access to their

devices, while manufacturers can find data gathered from IoT-capable products invaluable. In

this thesis, we use data from a growing fleet of IoT-connected boilers in the residential, lightcommercial, and medium-commercial ranges to demonstrate a framework for cluster initialization

and updating. We compare two methods of dynamically updating clusters: a sequential method

inspired by sequential K-means clustering and a cohesion-based method called DYNC. A predictive

artificial neural network system demonstrates the effectiveness of …

Remote Sensing, Modeling, And Spectroscopic Studies Of Gigantic Jets And Lightning Leaders, Levi Boggs

Theses and Dissertations

This dissertation focuses on four interrelated investigations with the ultimate goal of better understanding electrical phenomena in the lower and upper atmosphere. The four investigations utilized observations and data analysis for electrical discharges occurring in the troposphere, such as cloud-to-ground and intracloud discharges, and discharges occurring in the stratosphere/lower ionosphere, known as gigantic jets. The observations are from ground-based high-speed cameras and lightning locating systems, space-borne lightning imagers, and remote and in-situ meteorological instrumentation. Numerical modeling was also performed to study the lightning associated with gigantic jets by using a stochastic lighting propagation model. Finally, this dissertation focuses on the …

The Travel And Tourism Competitiveness Index: Examining The Reciprocal Relationship Among The Ttci Factors Relative To Porter’S (1998) Diamond Model And Airline Passenger Seat Capacity For The Countries Of The World, Hani Abdullah

Theses and Dissertations

The current study tested the application of Porter's (1998) diamond model of international competitiveness to the travel and tourism (T&T) industry by examining the relationship among the 14 factors of the travel and tourism competitiveness index (TTCI) to the model's four dimensions. The assignment of TTCI factors to these dimensions was guided by Dwyer and Kim (2003) and Ritchie and Crouch (2010). The study also examined the relationship between TTCI factors and airline passenger seat capacity, which was measured as the per capita annual average of weekly available seat kilometers. The sample comprised 136 countries, which represented 70% of the …

Runway Incursions: Examining Airport Managers’ Perspectives Of The Challenges Related To Vehicle/Pedestrian Deviations, John Arthur Mahlman Jr.

Theses and Dissertations

The purpose of the current study was twofold: (a) to describe the contributing factors of vehicle and pedestrian deviation (V/PD) runway incursions (RIs) nationally, and (b) to describe what mitigation approaches/strategies airport managers recommend or find to be effective. The current study used a content analysis in identifying airports with more than 10 V/PD RIs within Fiscal Years (FY) 2011 to FY 2016. After the study population was identified, phenomenological design was used to poll airport executives of the previously identified airports. The 11 participants elected to either complete an anonymous survey or participate in a telephone interview. Spradley’s (2016) …

Electronic Word-Of-Mouth (Ewom): Examining The Relationship Between Factors Influencing Ewom Activities And Passengers’ Purchasing Involvement In The Context Of Aviation, Ratchada Ruenruoy

Theses and Dissertations

The purpose of the study was manifold: (a) to examine the relationship a set of targeted factors has on electronic Word-of-Mouth (eWOM) activities in the context of aviation, (b) to examine the extent to which these factors affect airline passengers’ purchasing involvement, and (c) to determine the extent to which eWOM activities mediate the relationship between the targeted factors and purchasing involvement. Research factors included (a) purchasing perceptions, which consisted of satisfaction, loyalty, perceived value, and service quality; (b) social environment, which consisted of age, gender, and cultural differences relative to Hofstede’s (1980) cultural dimensions; and (c) experiences, which consisted …

Investigating The Effects Of Altitude And Flap Setting On The Specific Excess Power Of A Pa-28-161 Piper Warrior, Tjimon Meric Louisy

Theses and Dissertations

The high number of General Aviation (GA) accidents attributed to Loss of Control suggests that GA pilots are lacking low speed awareness and are unable to appropriately recognize when the aircraft is in a low energy state. There is, therefore, an urgent need for the development of an energy management system which is applicable to GA aircraft that can alert the pilot in situations of low energy conditions and recommends to the pilot the appropriate corrective action to restore conditions to a safe energy state. This will require the development of an algorithm that governs this energy management system that …

Dynamics Considerations Dedicated To Study Bodies In High-Altitude Free Fall, Michelle Carolina Rodriguez

Theses and Dissertations

The objective of this thesis is to develop a simulation model to study the dynamics of a rigid body in free fall. A set of 6 degrees of freedom (DOF) equations is developed to reflect the dynamic and trajectory characteristics over time. The simulation models a body dropped at different altitudes ranging from 30,480 – 39,624 m (100,000 – 130,000 ft). The trajectory of the body is analyzed using a mathematical nonlinear dynamics model. The mathematical model was developed in MATLAB and Simulink which can be modified for different geometries and conditions. The model was validated by testing that the …

Earth – Mars Cycler Vehicle Conceptual Design, Bhumika Patel

Theses and Dissertations

This thesis summarizes a conceptual design for an Earth – Mars Cycler vehicle designed to transfer astronauts between Earth and Mars. The primary objective of the design study is to accommodate the crews’ needs and to estimate the overall mass and power required during Earth – Mars transfer. The study defines a concept of operations and system functional requirements and discusses the systems breakdown and subsystems design analysis. Systems developed for the cycler vehicle is designed primarily for the S1L1 cycler trajectory. The initial sizing of cycler subsystems is based on reference data from historical human spaceflight. The study performed …

Development Of A Novel System For The Analysis Of The Cardiovascular And Autonomic Nervous Systems, Seyedmohsen Dehghanojamahalleh

Theses and Dissertations

Chapter 1 - An introduction to autonomic nervous system (ANS) and cardiovascular system (CVS): The performance of the ANS can be evaluated by quantizing the changes made by the autonomic nervous system. The most common parameters that are being used in autonomic nervous system assessment tests are blood pressure, heart rate, pressure pulse wave velocity, heart rate variability, and pulse waveform. In this dissertation, we designed and developed a system that assesses the activity of these two systems. Therefore, we represented four methods to 1- evaluate the dependence of neuro- and cardiovascular systems on sex, 2- non-invasively estimate the blood …

Home Automation System By Voice Commands, Noor Kamil Abdalhameed

Theses and Dissertations

The Home Automation System is one of the most important technologies that are used by humans for controlling electrical devices to reduce manual efforts in their daily tasks. The home automation system by voice has the ability to understand thousands of voice commands and perform the required action to control various electrical devices. The voice recognition is a bit complex and challenging task since each person has his accent. Therefore, Bitvoicer Server used in the home automation system in this thesis since it supports 17 languages from 26 countries and regions, and has the ability to recognize an unlimited number …

Mitigating Pilot Contamination Through Optimizing Pilot Allocation In Massive Mimo Systems, Rand Abdul Hussain

Theses and Dissertations

This dissertation has proposed several algorithms to optimize the allocation of pilots to the users’ equipment (UEs) to mitigate the effect of the pilot contamination problem in the massive MIMO systems. Pilot contamination reduces the performance of massive MIMO systems due to the reduction in the quality of the estimated channel between a UE and the serving base station (BS). The limitation of the number of samples in a coherence block limits the number of unique mutually orthogonal pilots, and hence, reusing the set of pilots across the cells causes inter-cell interference during pilot transmission, which is called pilot contamination. …

Socialization Of Veterans Using Virtual Reality, Joan M. Savage

Theses and Dissertations

Virtual reality, augmented reality, mixed reality, and video games are growing in popularity and fulfilling genuine human needs that the real world is currently unable to satisfy. Games are providing rewards that reality is not. They are teaching and inspiring and engaging us in ways that reality is not (McGonigal, 2011). The purpose of this study was to capture the essence of socialization in virtual reality as a Ph.D. dissertation topic at Florida Institute of Technology - Human-Centered Design. This study used a phenomenology methodology to capture the experiences of beneficial features of players who use virtual reality. The study …