Engineering Commons^™

Assessing The Condition Of Pavements (Road Surfaces) Using Computer Vision & Machine Learning, Syed Ibrahim Hassam

Doctoral

Regular inspections of pavements are conducted by civil infrastructure departments to evaluate the surface condition. Pavement surfaces are subject to deterioration caused by several factors such as traffic, weather, and sunlight. This deterioration becomes evident through various distresses, including potholes, rutting, cracking, bleeding, patching, and ravelling, which gradually affects the surface layer over time. It is essential to assess the condition of pavements as it not only ensures their usability but also maximises public safety. Effective pavement maintenance requires substantial resources and capital investment to carry out the most suitable maintenance treatments at the optimal time. Furthermore, the outcomes of …

Building Integration Of A Solar Air Heating System, Fernando Guerreiro

Doctoral

In order to achieve the global carbon emission target, the high fraction of locally available renewable energy sources will become necessary to meet energy demand. Solar energy is one of the most important renewable sources locally available for use in space heating, cooling, hot water supply and power production. Building integrated solar thermal systems (BISTS) can be a potential solution towards the enhanced energy efficiency and reduced operational cost in built environment. The current research aimed at developing an active solar air heating collector for building integration. This system consisted of several asymmetric compound parabolic concentrating collectors with inverted transpired …

Designing Ris-Assisted Uav 3d Trajectory Using Deep Reinforcement Learning, Linsong Li

Electronic Theses and Dissertations

Unmanned aerial vehicles (UAVs) are increasingly employed as temporary base stations or access points to facilitate data transfer between ground terminals (GTs). However, in urban environments, UAV-GT communication links often face challenges due to obstructions from buildings and other obstacles, resulting in reduced data transfer efficiency. Reconfigurable intelligent surfaces (RIS) provide a promising solution by reflecting signals to enhance communication quality between UAVs and GTs. This thesis addresses the critical challenge of responsive UAV trajectory optimization in RIS-assisted communication networks. A novel approach is proposed, integrating federated learning with reinforcement learning techniques, specifically Double Deep Q-Network (DDQN) and Deep Deterministic …

Molecular Modeling Of Phenolic Resin For Carbon-Carbon Composites, Ivan Gallegos

Dissertations, Master's Theses and Master's Reports

One of the most difficult challenges associated with space exploration is terrestrial atmospheric reentry due to the high thermal loads generated. Carbon carbon (C/C) composites have been used as heat shielding materials due to their high strengthto- weight ratio and thermal properties and their applications include heat shielding for various high temperature environments. C/C composites are manufactured by polymer-infiltration pyrolysis (PIP) via cycles of curing and pyrolysis of a prepreg which can be costly and take up to several days. Thus, C/C composites ideal candidates for computationally-driven optimization techniques, such as a multiscale Integrated Computational Materials Engineering (ICME) approach, by …

F-Temper Vs O-Temper Brazing Of 3003 Aluminum Return Bends, Mieka R. Clark

Dissertations, Master's Theses and Master's Reports

As-extruded (F-temper) 3003 return bends can provide cost savings over annealed (O-temper) return bends in aluminum heat exchangers. To assess if F-temper return bends are an alternative to the baseline O-temper bends, the grain structure, bending performance, and melting behavior were assessed through:

• Quantifying the effect of dispersoids on recrystallization
• Tracking bending behavior through grain morphology and surface texture
• Measuring the number and volume fraction of the α-Al(Mn,Fe)Si intermetallic
• Inducing incipient melting through high temperature thermal exposure.

When homogenized at 620°C and 630°C, the F-temper bends had no orange peel texture, the grain size was equivalent to the annealed product, …

Improving Cast Steel Rail Coupler Fatigue Resistance Through Local Wire-Arc Additive Manufacturing, Andrew M. Bunge

Dissertations, Master's Theses and Master's Reports

Every year, thousands of cast-steel railcar couplers suffer from corrosion-initiated fatigue cracking in similar areas of the coupler’s knuckle; between 2015 and 2018 about 90,000 knuckles were replaced, otherwise these couplers would have been at risk for unexpected failures. These types of couplers have been common in industrial use as early as 1932, hence it is desirable for a countermeasure to the fatigue cracking that does not involve significantly altering the geometry or casting process. Wire arc additive manufacturing (WAM) is a developing technology which boasts the ability to produce complex near-net-shape components; however, less attention has been paid to …

A Physical Test Artifact For Evaluating Edge Cases Of Individual And Fused Automated Driving Perception Sensors, Colin Schaefer

Dissertations, Master's Theses and Master's Reports

With the advent of technologies to support autonomous vehicles (AVs), the number of different AV models from a variety of companies and organizations has proliferated. With this increase in options comes the need to physically evaluate their perception systems. However, there is a lack of standard methods to physically evaluate these perception systems. A set of test artifacts can be used to compare the performances of perception systems, but the artifacts must be usable with different types of perception sensors and various sensor fusion systems. This thesis presents the development of an artifact that injects edge case scenarios into the …

High Temperature Strength Reduces Soldering In Aluminum High Pressure Die Casting, Jacob A. Belke

Dissertations, Master's Theses and Master's Reports

Die soldering, an adhesion defect in high pressure die casting (HPDC), is a symptom of localized sticking where a localized portion of the cast material is adhered to the tooling surface causing build up over time. This requires the tooling to be serviced which incurs additional costs to the process that gets passed on to the parts. Historically, soldering has been mitigated using lubricants, coatings, and alloy chemistry modifications but solder persists.

The Tresca friction thermomechanical model suggests soldering occurs when the local interfacial shear stress between the casting and die surface exceeds the local shear strength of the casting. …

Machine Learning For Electronic Structure Prediction, Shashank Pathrudkar

Dissertations, Master's Theses and Master's Reports

Kohn-Sham density functional theory is the work horse of computational material science research. The core of Kohn-Sham density functional theory, the Kohn-Sham equations, output charge density, energy levels and wavefunctions. In principle, the electron density can be used to obtain several other properties of interest including total potential energy of the system, atomic forces, binding energies and electric constants. In this work we present machine learning models designed to bypass the Kohn-Sham equations by directly predicting electron density. Two distinct models were developed: one tailored to predict electron density for quasi one-dimensional materials under strain, while the other is applicable …

Forecasting Of The Next Three (3) Decades Global Lithium Demand And Pricing Using Multivariate Stochastic Model., Enoch Nii- Okai

Dissertations, Master's Theses and Master's Reports

The transition to electric vehicles (EVs) is pivotal in achieving global climate goals, with nations aiming to integrate a significant portion of new passenger vehicles as electric by 2030. This shift towards electric mobility includes a notable rise in battery-electric, plug-in hybrid, and fuel-cell electric vehicles to curb carbon emissions and foster sustainable transportation. Central to this transition is the critical role of lithium, often referred to as the "white gold of the 21st century," in electric vehicle batteries, especially rechargeable lithium-ion batteries renowned for their high energy efficiency, density, and durability. While lithium has historically found extensive use across …

Study Of Nanoparticle Dispersed Phase Change Materials And The Impact Of Temperature Gradient On The Potential For Particle Migration, Udit Sharma

Dissertations, Master's Theses and Master's Reports

Supercooling in phase change materials (PCMs) and the associated challenges in enhancing thermal conductivity through nanoparticle dispersion prompted this investigation. Existing literature exhibits inconsistencies in thermal conductivity improvements, suggesting a potential correlation with nanoparticle migration induced by thermophoresis. To address this, a novel temperature-dependent scaling parameter, \(\xi\), was introduced to predict particle migration propensity. A strong association was observed between higher \(\xi\) values and diminished thermal conductivity enhancements, indicating a significant influence of nanoparticle movement on heat transfer.

To further elucidate this relationship, a Nanoparticle Interaction Parameter \(N_\text{{pl}}\) was developed, incorporating critical fluid properties and interfacial effects. The derived critical …

An Elasto-Plastic Constitutive Model With Phase-Field Fracture For Additively Manufactured Metallic Materials, Nolan Ruble

Dissertations, Master's Theses and Master's Reports

The advent of additive manufacturing (AM), commonly known as 3D printing, has revolutionized the production of metallic components across various industries. This technology, which builds objects layer by layer, has shifted paradigms in manufacturing, allowing for unprecedented design freedom, material efficiency, and rapid prototyping. Metal additive manufacturing, in particular, has shown remarkable promise due to its ability to produce complex geometries that are difficult or impossible to achieve with traditional subtractive methods. In addition, additively manufactured (AM) materials are gaining popularity in thanks to their often superior and controllable properties in comparison to their wrought counterparts. In the present work, …

Performance Characterization And Optimization Of A Point-Cloud-Based Path Planner In Off-Road Terrains, Casey D. Majhor

Dissertations, Master's Theses and Master's Reports

In this dissertation, I present a multifaceted study on the generation of artificial terrains using a multifractal method, and their use in autonomous ground vehicle (AGV) planning and navigation performance characterization in high-fidelity simulations, and automated parameter optimization.

My first contribution is a multifractal artificial terrain generation method leveraging the 3D Weierstrass-Mandelbrot function to control terrain roughness. We generate 60 unique off-road terrains while varying the fractal dimension and test the impact on vehicle traversal difficulty. Results show that increasing the fractal dimension decreases low-roughness areas, increases semi-rough and high-roughness areas, and decreases vehicle success rates while increasing vertical accelerations, …

Modeling Pulsatile Flows Using Truly Incompressible Finite Volume Lattice Boltzmann Model, Akshay S. Dongre

Dissertations, Master's Theses and Master's Reports

The present study addresses the compressibility error inherent in the standard Lattice Boltzmann Method (LBM) and LBM’s restriction to uniform Cartesian meshes. To mitigate the compressibility error, an incompressible LBM (iLBM) model has been incorporated into the finite volume framework using a cell-centered finite volume approach, leveraging the simplicity of the LBM algorithm for irregularly shaped flow domains with unstructured meshes. Monotonic Upstream-centered Scheme for Conservation Laws (MUSCL) and linear reconstruction (LR) schemes have been used to compute convective fluxes across the cell interfaces with boundary conditions implemented using the second-order accurate Non-Equilibrium Extrapolation (NEE) method.

The finite volume iLBM …

Sustainable Materials For Environment − Multifunctional Material Made From Dead Leaves And Nanostructured Materials For Antibiotic Degradation, Siyuan Fang

Dissertations, Master's Theses and Master's Reports

As environmental pollution from industrial processes and human activities continues to rise, finding efficient approaches to recycle waste materials and degrade persistent contaminants becomes increasingly critical. Dead leaves, an abundant but underutilized biomass, present an opportunity for creating value-added materials if their biocomponents can be preserved and transformed. Simultaneously, antibiotics such as tetracycline are widely found in water bodies but pose serious ecological and health risks, necessitating effective degradation methods. This dissertation addresses these challenges by leveraging natural and nanostructured materials to develop multifunctional products and advanced photocatalytic processes.

Chapter 3 of this dissertation addresses the challenge of converting waste …

Phase Field Modeling Of Fracture And Phase Separation Using Numerical Methods And Machine Learning, Revanth Mattey

Dissertations, Master's Theses and Master's Reports

Phase field modeling is a crucial tool in scientific and engineering disciplines due to its ability to simulate complex phenomena like phase transitions, interface dynamics, and pattern formation. It plays a vital role in understanding material behavior during processes such as solidification, phase separation, and fracture mechanics. Particularly in fracture mechanics, phase field modeling can be utilized to predict the crack path in complex materials. Understanding the failure behavior is vital for applications of any material. The specific contributions to the field of phase field fracture mechanics, are, Firstly, we propose a novel phase field fracture model to simulate the …

Effective Data Augmentation Techniques For Time Series Classification: An Empirical Evaluation, Pongpanod Sankosik

Chulalongkorn University Theses and Dissertations (Chula ETD)

Time series classification is crucial in fields such as healthcare, finance, and industrial processes, but it faces challenges like temporal data ordering, class im-balance, noise, and limited data. This research explores data augmentation techniques to improve classification performance, focusing on the MiniRocket classifier across 85 UCR datasets. The study identifies conditions under which augmentation techniques, like wDBA, enhance accuracy, though overall performance may vary. A dataset-specific approach is essential for effective augmentation. The research also examines the impact of augmentation on datasets with different characteristics, providing insights into when specific strategies are most benefi-cial. Future work includes optimizing augmentation methods …

Exploring Market Segmentation For Autonomous Ferries, Ashari Fitra Rachmannullah, Taih Cherng Lirn, Kuo Chung Shang

Journal of Marine Science and Technology–Taiwan

This study aims to investigate the determinants that underlie psychographic segmentation in the domain of autonomous ferries (AFs) by using the theory of planned behaviour (TPB) as a guiding theoretical construct. The paper focuses on Indonesian individuals who had previously utilised conventional ferry services. TPB was applied as a catalyst to identify possible market segmentation among potential AF passengers. In this study, cluster analysis is used to differentiate passengers by their perception of using AFs. The results identified three market segments through cluster analysis based on passengers’ perceptions of using AFs: Resource-Limited, Resource-Capable, and Value-Optimistic. Among these segments, the Resource-Capable …

Adaptive Prediction Horizon Energy-Saving Collision-Free Mpc Of Ships Based On Ship-Shore Cooperation, Han Xue, Enjie Yang

Journal of Marine Science and Technology–Taiwan

ABSTRACT:In order to perform the close association between ship maneuvering control and energy consumption through the control strategy, this paper designs an adaptive prediction horizon based energy-saving robust nonlinear model predictive control (APHERNMPC) for underactuated ships to deal with the actual control and state constraints during berthing based on ship-shore cooperation. An improved Emperor Penguin Optimizer (EPO) method is proposed for collision avoidance decision. To solve the problems of falling into local optimum and reducing the convergence speed, the traditional EPO is improved based on Sobol sequence in order to enhance the diversity and ergodicity of the population. The multi-ship …

Research And Design A Lifeboat Virtual Reality Simulation System For Maritime Safety Training In Vietnam, Nguyen Dinh Thach, Nguyen Van Hung

Journal of Marine Science and Technology–Taiwan

Ensuring maritime safety and security is crucial for all nations. Training trainees and operational officers in this field aims to enhance their professional skills and ability to manage and resolve incidents at sea. This article outlines the development of a lifeboat simulation system that integrates Virtual Reality (VR) technology in accordance with international maritime regulations. It describes the creation of an algorithm designed to optimize data transmission between simulation systems using the ant colony optimization technique in conjunction with intelligent control algorithms on Unity 3D software for human interaction. In particular, the system combines training with a maritime simulation framework …

Preliminary Remote Identification Of Unstable Zone On Large-Scale Waste Dump At Mae Moh Mine Using Insar Technique, Chitra Buth

Chulalongkorn University Theses and Dissertations (Chula ETD)

Mae Moh Mine is one of the largest lignite mine in Southeast Asia, operated by the Electricity Generating Authority of Thailand (EGAT). It is located in the northern part of Thailand, in Mae Moh district, Lampang province. In March 2018, a significant sliding incidence occurred at a waste dump site with sliding area of 1.56 km2 approximately, highlighting the pressing issue of instability within this large-scale waste dump area. This study aims to address this concern in the future and demonstrate an innovative method for investigating the failure by employing Interferometric Synthetic Aperture Radar (InSAR) technology. The methodology involves the …

Sales Forecasting For Retail Business Using Xgboost Algorithm And Timesfm, Prathana Dankorpho

Chulalongkorn University Theses and Dissertations (Chula ETD)

The retail industry is continuously evolving with the expansion of sales channels and the diversification of product assortments. However, current forecasting methods, relying on simplistic statistical models, frequently encounter difficulties in adjusting to the dynamic environment. This limitation leads to challenges in accurately predicting sales. Consequently, there is a critical need to improve the accuracy and frequency of sales predictions to enable timely decision-making for business strategies. Through a comprehensive analysis of datasets from 2019 to 2023, this study illustrates the advantages of integrating XGBoost and TimesFM to gain deeper insights into sales patterns. Results demonstrate a significant enhancement in …

Adaptive Trust Management For Data Poisoning Attacks In Mec-Based Fl Infrastructures, Abeer Hamdy Dr.

Computer Science

Federated Learning (FL) has emerged as a powerful paradigm, allowing multiple decentralized clients to collaboratively train a machine learning model without sharing their raw data. When combined with Multi-access Edge Computing (MEC), it enhances the utilization of computation and storage resources at the edge, enabling local data training on edge nodes. Such integration reduces latency and facilitates real time processing and decision-making while ensuring data privacy. However, this decentralized approach introduces security and trust challenges, as models can be compromised through data poisoning attacks, such as label flipping attacks. The trustworthiness of these edge nodes and the integrity of their …

Evaluation Of Aashto Seismic Design For Reinforced Concrete Bridge Columns, Andrew Leroy Grismer

Electronic Theses and Dissertations

Bridge failure can be catastrophic resulting in casualties and limiting the accessibility and emergency response efforts. Ensuring a high level of ductility for bridge columns through sufficient design methods and detailing is the most important aspect of the modern seismic codes. Reinforced concrete (RC) bridge columns are widely used in multi-span bridges located in seismic regions of the nation due to their controlled ductility and durability. The objective of this study was to systematically evaluate the AASHTO seismic design requirements for RC bridge columns and to comment on whether current bridge code is sufficient and safe. An extensive literature review …

Optimizing Large Language Models And Multimodal Approaches For Biomedical Publication And Satellite Imagery, Youngsun Jang

Electronic Theses and Dissertations

This dissertation comprises two main sections: the first focuses on natural language processing (NLP) for extracting key information from scientific literature using large language models (LLMs), and the second addresses remote sensing for detecting natural disasters, such as floods, from satellite imagery using a multimodal approach. The first section investigates methods to enhance Transformer-based models in classifying and extracting information from biomedical scientific publications. Key contributions include the development of a custom dataset for classification and Question and Answering (Q&A) tasks, fine-tuning Transformer models like the Bidirectional Encoder Representations from Transformers (BERT) and addressing multi-span answer issues with the TAg-based …

Development Of Bed Shear Stress In Open Channel Flow In Smooth-To-Rough And Rough-To-Smooth Transitions, Linet Chietunda Paul

Electronic Theses and Dissertations

The study of flows over sudden change in bed roughness in open channels is important in understanding the flow dynamics of a developing boundary layer. Parameters such as shear velocity, mean flow velocity, turbulence intensity and the Reynolds stress distribution are critical in channel design optimization and predicting sediment transport. In this thesis, a detailed examination of the distribution of these parameters is undertaken in a rough-to-smooth and smooth-to-rough transition. Laboratory experiments were conducted on rough-to-smooth transition (Case A) and smooth-to-rough transition (Case B) in an open channel flume. Measurements of the fluid velocity fields at the centerline of the …

Incorporating Evidence-Based Teaching Practices In A Civil/Environmental Engineering Course To Improve Learning, Julie Anne Wildschut

University Faculty Publications and Creative Works

The most important goal of teaching is student learning, passing on information from the instructor to the student so they can apply those concepts and skills months and years after instruction. However, this goal is not easily accomplished. Thinking and learning take significant effort and students often resist putting in the required work. Additionally, the increasingly diverse student population and recent disruptions to traditional classroom learning require instructional design to meet learning outcomes. Three evidence-based teaching practices including retrieval practice, spaced (distributed) practice, and interleaving were incorporated into a hydraulics course to improve student learning and evaluated for their effectiveness. …

Height Adjustable Kitchen Work And Dining Surface, Jay Van Voorhis , '24

Senior Theses, Projects, and Awards

No abstract provided.

Tokyo-Bot: Emulating Industrial Automation, Erebus Oh , '24, Aaron Omadutt , '24, Dzineon Gyaltsen , '24

Senior Theses, Projects, and Awards

Our E90 project was to design, assemble, and program an omni-directional robot that integrated a web camera to intelligently sort (and ideally transfer from one location to another) colored boxes. The purpose of this project was to simulate an industrial workplace setting where similar types of sorting processes occur, and be able to optimize them. Developing a robot with high maneuverability combined with object detection capabilities could prove to be useful in optimizing workflows in warehouses and processing factories where items constantly need to be located and transported. With three group members, each with their own specializations, the project was …

Elm Avenue Storm Drain Outfall Surge Control, Jasper Ferncrombie , '24

Senior Theses, Projects, and Awards

I designed a control structure just past the storm drain outfall at the end of Elm Avenue near Swarthmore College’s North entrance. This structure will allow the large, fast-moving flow from the outfall to be discharged in a more controlled manner after rain events, preventing erosion and damage to the Crum Woods downstream of the outfall. To create my design, I consulted with experienced professionals and created a model of the contributing drainage area to determine the site needs and characteristics to decide an appropriate design. For the design itself, I used CAD and GIS software to model the size, …