Engineering Commons^™

Harnessing Technology To Solve Social Problems, Ian Hassell

SMU Human Trafficking Data Conference

No abstract provided.

Expanding The Horizon: Blockchain Technology Beyond The Bounds Of Cryptocurrency, Hassan Azhar

SMU Data Science Review

Blockchain technology has extended beyond its initial role as the infrastructure for cryptocurrencies to transform various industries with its decentralized and transparent ledger system. This paper examines the broad spectrum of blockchain applications beyond cryptocurrency. It explores its potential to innovate and drive change across finance, supply chain management, healthcare, real estate, and voting systems. We review recent literature, detail specific use cases, and discuss blockchain's challenges and opportunities, aiming to provide a comprehensive overview of its transformative impact. Integrating emerging technologies, scalability, regulatory considerations, and energy consumption are critical challenges to its adoption. Our findings underscore the need for …

Beyond The Horizon: Exploring Anomaly Detection Potentials With Federated Learning And Hybrid Transformers In Spacecraft Telemetry, Juan Rodriguez

Computer Science and Engineering Theses and Dissertations

Telemetry sensors play a crucial role in spacecraft operations, providing essential data on efficiency, sustainability, and safety. However, identifying irregularities in telemetry data can be a time-consuming process that risks the success of missions. With the rise of CubeSats and smallsats, telemetry data has become more abundant, but concerns about privacy and scalability have resulted in untapped data potential. To address these issues, we propose a new approach to anomaly detection that utilizes machine learning models at data sources. These models solely transmit weights to a centralized server for aggregation, resulting in improved dataset performance with a single global model. …

Wireless Power Transfer Using Cavity With Height Discontinuities, Linsheng Zhang

Electrical Engineering Theses and Dissertations

A novel device for efficient wireless power transfer (WPT) system is presented. The proposed WPT system utilizes modified microstrip antennas with height discontinuities (MAHDs) to achieve power transfer. Similar to the conventional WPT system using inductive devices, the power transmission relies on the magnetic field coupling in the near field region. However, the researcher can treat the isolated transmitter or receiver as a modified microstrip antenna, which resembles a capacitive device. Like a capacitive antenna, we can utilize the cavity model, which significantly simplifies field analysis, design and impedance matching process, reduces the overall space requirement, and potentially increases the …

Uav-X Communication: Empirical Characterization And Performance Optimization, Muhammad Hashir Syed

Electrical Engineering Theses and Dissertations

In emerging wireless networks, the scalability of deploying drones presents an opportunity to design extensive aerial networks. These networks could effectively monitor large agricultural fields from the air and soil for food production with efficient resource utilization. On the one hand, unmanned aerial vehicles (UAVs) have gained interest in agricultural aerial inspection due to their ubiquity and observation scale. On the other hand, agricultural internet-of-thing devices, including buried soil sensors, have gained interest in improving natural resource efficiency in crop production. In this work, we investigate the natural interaction of these two phenomena, where UAVs can be leveraged as flying …

Essays In Robust Optimization With Applications To Finance And Renewable Energy, Hao Jiang

Operations Research and Engineering Management Theses and Dissertations

Real-world optimization problems are often sensitive to uncertainties caused by estimation errors, forecasting inaccuracy, and imprecise data information. These uncertainties bring significant challenges to decision-making in many areas. Robust optimization (RO) is a tool for addressing the challenges of parameter uncertainty. In this dissertation, we focus on the studies of RO on two problems. (1) In the study of finance, we proposed a tractable RO model for a Mean-Variance portfolio selection problem. We consider Markowitz's Mean-Variance Optimization when stock returns are modeled using Sharpe's single-index framework, but the model coefficients Alpha and Beta, are not precisely known. This study assumes …

Design And Fabrication Of A Low Power 7.2 Terabit Transmitter For Exascale Computing, Scott Mcwilliams

Electrical Engineering Theses and Dissertations

Enhanced Coupled Strength (ECS) gratings fabricated into III-V based devices offer high reflected power per unit length and broad band reflectivity as compared to conventional 1st order gratings, desired qualities for short-haul high speed transmitters that can be implemented without the need for chip-level temperature control, contributing to the low power per transmitted bit. For commercial DBR lasers, the grating reflectivity results in an extremely narrow reflectivity spectrum, which is highly desired for most/many applications, but requires a power hungry thermo-electric cooler to maintain a fixed frequency. The proposed LEAM (laser electro-absorption modulator) requires a broad reflectivity spectrum, which, by …

Series Aperture Coupled Fed Phased Array Antenna, Guang Yang

Electrical Engineering Theses and Dissertations

Phased arrays are employed in a wide range of civil and Military contexts, including RADAR, cellular communications, and satellite communications. However, modern phased-array antennas require complex design and bulky structure at high costs, hindering their implementation in many applications. The critical aspect of a phased array design lies in power splitting with a proper phase to each radiating element. Conventional power splitters such as quarter-wavelength or Wilkinson power splitters suffer problems associated with complex array network and high power dissipation. Furthermore, popular phase shifters such as MEMS switch, ferrite-based or PIN diode have drawbacks of low power-handling capability, expensive packaging, …

Modeling And Compensating Of Noise In Time-Of-Flight Sensors, Bryan Rodriguez

Electrical Engineering Theses and Dissertations

Three-dimensional (3D) sensors provide the ability to perform contactless measurements of objects and distances that are within their field of view. Unlike traditional two-dimensional (2D) cameras, which only provide RGB data about objects within a scene, 3D sensors are able to directly provide depth information for objects within a scene. Of these 3D sensing technologies, Time-of-Flight (ToF) sensors are becoming more compact which allows them to be more easily integrated with other devices and to find use in more applications. ToF sensors also provide several benefits over other 3D sensing technologies that increase the types of applications where ToF sensors …

Static Malware Family Clustering Via Structural And Functional Characteristics, David George, Andre Mauldin, Josh Mitchell, Sufiyan Mohammed, Robert Slater

SMU Data Science Review

Static and dynamic analyses are the two primary approaches to analyzing malicious applications. The primary distinction between the two is that the application is analyzed without execution in static analysis, whereas the dynamic approach executes the malware and records the behavior exhibited during execution. Although each approach has advantages and disadvantages, dynamic analysis has been more widely accepted and utilized by the research community whereas static analysis has not seen the same attention. This study aims to apply advancements in static analysis techniques to demonstrate the identification of fine-grained functionality, and show, through clustering, how malicious applications may be grouped …

Climate-Driven Changes In Water Quality By Physiographic Region: A Case Study Of Taos County, New Mexico, Michaela Eamma

Civil and Environmental Engineering Theses and Dissertations

Socioeconomic growth and stability in rural regions of the United States where agriculture is the dominant industry are highly reliant on access to sufficient surface water supplies. The water quantity crisis experienced worldwide in recent years has introduced questions about how to best maintain the quality of our remaining resources. Ensuring adequate access to drinking and irrigation water mandates that we protect existing surface water sources and anticipate future threats to quality. The impact of climate change on surface water quality is not spatially uniform, introducing the need to study the water-atmosphere-land system comprehensively.

This research aims to study the …

Study Of Radiation Effects In Gan-Based Devices, Han Gao

Electrical Engineering Theses and Dissertations

Radiation tolerance of wide-bandgap Gallium Nitride (GaN) high-electron-mobility transistors (HEMT) has been studied, including X-ray-induced TID effects, heavy-ion-induced single event effects, and neutron-induced single event effects. Threshold voltage shift is observed in X-ray irradiation experiments, which recovers over time, indicating no permanent damage formed inside the device. Heavy-ion radiation effects in GaN HEMTs have been studied as a function of bias voltage, ion LET, radiation flux, and total fluence. A statistically significant amount of heavy-ion-induced gate dielectric degradation was observed, which consisted of hard breakdown and soft breakdown. Specific critical injection level experiments were designed and carried out to explore …

Effect Of Surface Fluid Entrapment In A Laminar Flat Plate Boundary Layer, Abigail Hays

Mechanical Engineering Research Theses and Dissertations

For streamlined objects in laminar flow, the drag is dominated by friction drag. To counteract this, the boundary condition of the object can be changed to introduce an apparent slip on the surface. A number of approaches have been proposed for introducing surface slip to reduce drag and viscous resistance in fluid flows. This work investigates a novel approach to providing slip via fluid entrapment in a perforated domain embedded in the surface. The fluid entrapment system uses a cavity underneath the domain to allow entrapment of fluid of the same type, or supply air to the surface perforations in …

Photonic Sensors Based On Integrated Ring Resonators, Jaime Da Silva

Mechanical Engineering Research Theses and Dissertations

This thesis investigates the application of integrated ring resonators to different sensing applications. The sensors proposed here rely on the principle of optical whispering gallery mode (WGM) resonance shifts of the resonators. Three distinct sensing applications are investigated to demonstrate the concept: a photonic seismometer, an evanescent field sensor, and a zero-drift Doppler velocimeter. These concepts can be helpful in developing lightweight, compact, and highly sensitive sensors. Successful implementation of these sensors could potentially address sensing requirements for both space and Earth-bound applications. The feasibility of this class of sensors is assessed for seismic, proximity, and vibrational measurements.

Grammatical Triples Extraction For The Distant Reading Of Textual Corpora, Stephanie Buongiorno, Stephanie Buongiorno

Multidisciplinary Studies Theses and Dissertations

Grammatical triples extraction has become increasingly important for the analysis of large, textual corpora. By providing insight into the sentence-level linguistic features of a corpus, extracted triples have supported interpretations of some of the most relevant problems of our time. The growing importance of triples extraction for analyzing large corpora has put the quality of extracted triples under new scrutiny, however. Triples outputs are known to have large amounts of erroneous triples. The extraction of erroneous triples poses a risk for understanding a textual corpus because erroneous triples can be nonfactual and even analogous to misinformation. Disciplines such as the …

Equity In Transportation: Data Driven Analysis Of Transportation Services And Infrastructures, Javad Jomehpour Chahar Aman

Civil and Environmental Engineering Theses and Dissertations

Achieving equity in transportation is an ongoing challenge, as transportation options still vary tremendously when it comes to marginalized populations. This dissertation addresses this challenge by conducting a comprehensive review of existing transportation equity literature and identifying two critical gaps: the lack of data-driven approaches to studying spatial mismatch between transportation supply and demand, and limited information on women's perceptions and expectations towards emerging transportation services.

Chapter two introduces the concept of transportation "deserts," specifically transit deserts and walking deserts, and develops data-driven frameworks to identify and investigate neighborhoods with limited transportation service supply but high demand. The frameworks compare …

A Mechanics-Based Analytical Solution For Restrained Beams With Application To Progressive Collapse Behavior, Leven Deputy

Civil and Environmental Engineering Theses and Dissertations

This dissertation presents an axially restrained beam (ARB) model that incorporates axial-flexural interaction throughout the entire static load-deflection curve: the elastic material range, the plastic, flexural dominant range, the range beyond plastic flexure with increasing catenary effect, and the full catenary range. Energy methods are applied to static load-deflection curves to determine dynamic load-deflection relationships. Specifically, this dissertation considers the two conditions; Pinned-Pinned-Pinned (PPP) which has no flexural resistance at the boundaries, and Fixed-Fixed-Fixed FFF (also Pinned-Fixed-Pinned, PFP) condition which provides the beam with flexural resistance at the boundaries equal to flexural capacity of the beam. Behavior is explained analytically …

Transport Mechanisms In Electrochemical Immunoassay Biosensors With Applications To Sarscov-2 Neutralizing Antibody Detection, Mohammad Karim Dehghan Manshadi

Mechanical Engineering Research Theses and Dissertations

Biosensors are used in diverse applications spanning from clinical diagnosis and drug discovery to environmental and safety monitoring. Among different types of biosensors, electrochemical ones have demonstrated high sensitivity, short detection time, and selectivity with a low cost, and have been widely used to detect various diseases. In this thesis, we have introduced an inexpensive, rapid, sensitive, and quantifiable impedance-based immunosensors to evaluate SARS-CoV-2 neutralizing antibody (NAb), which shows the real protective immunity against COVID-19. We demonstrated that our device enabled assessment of NAb in a physiological buffer with conductivity equivalent to that of blood plasma. This technique can be …

Nonconvex Optimization For Statistical Learning With Structured Sparsity, Chengyu Ke

Operations Research and Engineering Management Theses and Dissertations

Sparse learning problems, known as feature selection problems or variable selection problems, are a popular branch in the field of statistical learning. When faced with a dataset with only a few observations but a large number of features, we are interested in extracting the most useful features automatically by solving an optimization problem. In this dissertation, we start by introducing a novel penalty function as well as an iterative reweighted algorithm to solve the group sparsity problem, a special type of feature selection problems. The penalty function, named group LOG, shows a better ability to recover the ground-truth compared to …

Component Testing And Characterization Of An Innovative Pressurized Sand Damper For The Response Modification Of Structures, Konstantinos Kalfas

Civil and Environmental Engineering Theses and Dissertations

This study is partly motivated by the need to develop sustainable energy dissipation devices that do not suffer from oil leakage due to failure of their end seals and from displacement limitations; and partly from the need to develop a robust damper that consists only of traditional civil engineering materials (sand and steel) in association with the use of post-tensioned steel rods with which practitioner civil engineers are familiar. Past failures of fluid dampers are both disruptive and costly, therefore not in-line with the current design paradigm of sustainable engineering, where the design and construction of structural systems shall meet …

Indirect Bridge Monitoring Using Crowdsourced Smartphone Data From Passing Vehicles, Jase Sitton

Civil and Environmental Engineering Theses and Dissertations

Bridges become susceptible to deterioration and damage as they age and are subjected to continually increasing demands. Bridge inspections help insure the integrity and safety for service and are conducted on a regular, but usually infrequency, basis. Traditional evaluation methods include visual inspections and permanent sensor installations. Visual inspections are both time and labor intensive and often require bridge closure or service interruption, while cost and logistics complications often prevent practical, widespread deployment of permanent sensor installations. Sensors, including smartphones, in moving vehicles may be used to monitor bridge condition over time and provide valuable insight into the dynamic behavior …

Self-Learning Algorithms For Intrusion Detection And Prevention Systems (Idps), Juan E. Nunez, Roger W. Tchegui Donfack, Rohit Rohit, Hayley Horn

SMU Data Science Review

Today, there is an increased risk to data privacy and information security due to cyberattacks that compromise data reliability and accessibility. New machine learning models are needed to detect and prevent these cyberattacks. One application of these models is cybersecurity threat detection and prevention systems that can create a baseline of a network's traffic patterns to detect anomalies without needing pre-labeled data; thus, enabling the identification of abnormal network events as threats. This research explored algorithms that can help automate anomaly detection on an enterprise network using Canadian Institute for Cybersecurity data. This study demonstrates that Neural Networks with Bayesian …

Towards Multipronged On-Chip Memory And Data Protection From Verification To Design And Test, Senwen Kan, Jennifer Dworak

Computer Science and Engineering Theses and Dissertations

Modern System on Chips (SoCs) generally include embedded memories, and these memories may be vulnerable to malicious attacks such as hardware trojan horses (HTHs), test access port exploitation, and malicious software. This dissertation contributes verification as well as design obfuscation solutions aimed at design level detection of memory HTH circuits as well as obfuscation to prevent HTH triggering for embedded memory during functional operation. For malicious attack vectors stemming from test/debug interfaces, this dissertation presents novel solutions that enhance design verification and securitization of an IJTAG based test access interface. Such solutions can enhance SoC protection by preventing memory test …

Experimental And Numerical Studies On Laser Hot Wire Cladding By A High-Power Direct Diode Laser, Mingpu Yao

Mechanical Engineering Research Theses and Dissertations

Laser hot wire cladding is an advanced surface modification technology. It has been extensively growing during the last decades due to its high deposition rate, good metallurgical bonding between the substrate and clad layer, low dilution ratio, and small heat-affected zone. There are many kinds of lasers widely used in the laser cladding process. The high-power direct diode laser is widely welcomed because of its high energy efficiency, high electro-optic conversion efficiency, low cost, and high reliability. A rectangular-shaped direct diode laser beam combined with hot wire feeding can achieve a lower dilution depth with a uniform fusion line compared …

An Investigation Of The Role Of System Effectiveness In The Acquisition And Sustainment Of U.S. Defense Systems: 1958 To 2022, John Green

Operations Research and Engineering Management Theses and Dissertations

This dissertation investigates the role of the system effectiveness methodology in acquiring and sustaining U.S. military weapons systems from 1958 to 2021. The period of interest has seen numerous changes in both the acquisition process and the application of system effectiveness to acquisition and sustainment. Several of the changes were disruptive, including shifting acquisition and sustainment to a commercial paradigm and completely overhauling the approach to acquiring new systems. The method of inquiry integrated three qualitative methods–structured literature review, grounded theory analysis, and historiography–into an innovative approach for investigating the changes to system effectiveness. The database for the investigation was …

Compact Formulation Of Multicommodity Network Flows With Applications To The Backhaul Profit Maximization Problem And Fixed Charge Network Flow Problem, Yulan Bai

Operations Research and Engineering Management Theses and Dissertations

The triples formulation is a compact formulation of multicommodity network flow problems that provides a different representation of flow than the traditional and widely used node-arc and arc-path approaches. In the literature, the triples formulation has been applied successfully to the maximum concurrent flow problem and to a network optimization problem with piecewise linear convex costs. This dissertation applies the triples formulation to the backhaul profit maximization problem (BPMP) and the fixed charge network flow problem (FCNF). It is shown that the triples representation of multicommodity flow significantly reduces the number of variables and constraints in the mixed integer programming …

Development And Application Of A Design Flow For Photonic Integrated Circuits, Ifeanyi Achu

Electrical Engineering Theses and Dissertations

Silicon photonics allows for the fabrication of many optical elements on a single photonic integrated circuit (PIC). By taking advantage of the established foundry technology used in the CMOS and silicon’s high refractive index, high feature density manufacturing can be achieved in mass quantities. In CMOS fabrication, from conception of an electronic circuit to testing, the process of designing an electronic circuit is dictated by a design flow which has been developed over the course of decades. This flow includes circuit level design and simulation, layout of the circuit, layout and verification of the chip, fabrication, packaging, and testing. Given …

Leveraging Crowdsourced Navigation Data In Roadway Pluvial Flash Flood Prediction, Arefeh Safaei-Moghadam

Civil and Environmental Engineering Theses and Dissertations

This dissertation develops and tests a new data-driven framework for short-term roadway pluvial flash flood (PFF) risk estimation at the scale of road segments using crowdsourced navigation data and a simplified physics-based PFF model. Pluvial flash flooding (PFF) is defined as localized floods caused by an overwhelmed natural or engineered drainage system. This study develops a data curation and computational framework for data collection, preprocessing, and modeling to estimate the risk of PFF at road-segment scales. A hybrid approach is also developed that couples a statistical model and a simplified physics-based simulation model in a machine learning (ML) model to …

Energy Dissipation In A Sand Damper Under Cyclic Loading, Ehab Sabi

Civil and Environmental Engineering Theses and Dissertations

Various seismic and wind engineering designs and retrofit strategies have been in development to meet structures' proper and safe operation during earthquake and wind excitation. One such method is the addition of fluid and particle dampers, such as sand dampers, in an effort to reduce excessive and dangerous displacements of structures. The present study implements the discrete element method (DEM) to assess the performance of a pressurized sand damper (PSD) and characterize the dissipated energy under cyclic loading. The idea of a PSD is to exploit the increase in shearing resistance of sand under external pressure and the associated ability …

Orbital Angular Momentum Orthogonality-Based Crosstalk Reduction: Theory And Experiment, Unaiza Tariq

Electrical Engineering Theses and Dissertations

Full duplex communication systems allow a single channel to be used for simultaneous two-way communication, increasing spectral efficiency. However, full duplex communication systems suffer from the issue of self-interference between local transmitter and receiver antennas. Analog subtraction and signal processing methods have previously been used to reduce this problem. This dissertation proposes the use of waves carrying orbital angular momentum (OAM) to mitigate the problem of self-interference by offering a means of additional isolation between local antennas.

Orbital angular momentum has been widely studied both in the photonics and radio domain. The theoretically infinite orthogonal states of an OAM signal …