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Articles 14581 - 14610 of 198078

Full-Text Articles in Engineering

Personalized Persuasion In The Digital Age: A Data-Driven Approach To Effective Communication, Annye Braca Jan 2025

Personalized Persuasion In The Digital Age: A Data-Driven Approach To Effective Communication, Annye Braca

Doctoral

This thesis investigates the potential of Machine Learning (ML) to personalize persuasive marketing messages. It explores the identification of individuals receptive to specific persuasion techniques based on their psychometric profiles. By developing ML models that incorporate these profiles, the thesis aims to predict the impact of tailored messages and improve the effectiveness of marketing communication.


Highly Sensitive Diffractive Optical Structures For Detection Of Volatile Organic Compounds, Faolan Radford Mcgovern Jan 2025

Highly Sensitive Diffractive Optical Structures For Detection Of Volatile Organic Compounds, Faolan Radford Mcgovern

Doctoral

From aerospace to agriculture, sensors play a fundamental role in many aspects of modern life. Sensors form an integral part of the complex systems and devices required for the continued functioning and development of services and industries across society. The use of sensors is paramount in areas affecting human health, one such area being the monitoring of indoor air quality, in particular the detection of volatile organic compounds (VOCs). Human contact with VOCs has been associated with many health complications, including skin and eye irritation, cardiovascular damage, and cancers. Optical, electrical, gravimetric, and chemical sensors have been developed for VOC …


Classification Of Indonesian Sign Language (Sibi) Using Data Mining Algorithms K-Nearest Neighbor And Random Forest, Muhammad Zaki Wirawan, Achmad Afif, Anik Nur Handayani, Imanuel Hitipeuw, Osamu Fukuda Jan 2025

Classification Of Indonesian Sign Language (Sibi) Using Data Mining Algorithms K-Nearest Neighbor And Random Forest, Muhammad Zaki Wirawan, Achmad Afif, Anik Nur Handayani, Imanuel Hitipeuw, Osamu Fukuda

Knowledge Engineering and Data Science

This study aims to address the communication hallenges faced by the Indonesian deaf community by developing an automatic classification model for Sistem Bahasa Isyarat Indonesia (SIBI) using data mining techniques. The main objective is to identify a practical algorithm for recognizing SIBI hand gestures to enhance accessibility and inclusiveness in digital communication. A comprehensive dataset consisting of 32,850 gesture samples representing SIBI alphabet signs was collected and processed through feature extraction, data cleaning, and normalization using Z-Transform and Min-Max methods. Two classification algorithms, K-Nearest Neighbor (KNN) and Random Forest, were implemented and evaluated using metrics such as accuracy, precision, recall, …


A Comparative Study Of Machine Learning Models For Javanese Wuku Classification: Exploring Svm, Naïve Bayes, And Cnn For Cultural Texts, Danang Arbian Sulistyo, Aji Prasetya Wibawa, Didik Dwi Prasetya, Fadhli Almu'iini Ahda, Agung Bella Putra Utama Jan 2025

A Comparative Study Of Machine Learning Models For Javanese Wuku Classification: Exploring Svm, Naïve Bayes, And Cnn For Cultural Texts, Danang Arbian Sulistyo, Aji Prasetya Wibawa, Didik Dwi Prasetya, Fadhli Almu'iini Ahda, Agung Bella Putra Utama

Knowledge Engineering and Data Science

This study rigorously evaluates machine learning models for classifying culturally significant Javanese Wuku texts from the “Keagamaan atau Spiritual” category, a domain challenged by unique linguistic nuances and limited digitized resources. We compared Support Vector Machine (SVM), Naïve Bayes, and Convolutional Neural Network (CNN) on texts from five pivotal Wuku types (Sinta, Galungan, Kuningan, Sungsang, Warigalit) sourced from sastra.org, aiming to identify the most effective computational approach. The dataset comprises N = 1419 documents (T = 751.290 tokens), with per-class document counts reported for all five Wuku types. Our evaluation uses accuracy, precision, recall, F1-score, and …


The International Risk Governance Council: Reflections On A 20-Year Experiment In Support Of Improved Risk Governance, M. Granger Morgan, Marie-Valentine Florin, Igor Linkov, Kenneth A. Oye, Arthur C. Petersen, Ortwin Renn, Jonathan B. Wiener, Lan Xue Jan 2025

The International Risk Governance Council: Reflections On A 20-Year Experiment In Support Of Improved Risk Governance, M. Granger Morgan, Marie-Valentine Florin, Igor Linkov, Kenneth A. Oye, Arthur C. Petersen, Ortwin Renn, Jonathan B. Wiener, Lan Xue

Faculty Scholarship

The International Risk Governance Council (IRGC) was a nonprofit foundation, based first as an independent, freestanding Swiss foundation in Geneva from 2003 to 2012, and then affiliated with École Polytechnique Fédérale de Lausanne in Lausanne from 2012 to 2023. IRGC's mission was to identify and improve the governance of emerging and systemic risks that have, or could have, impacts on human and environmental health, the economy and society, and overall sustainability. In this paper, we recount IRGC's history, describe its many reports, workshops, and conference activities (including tables referencing the many published products), and provide six brief case histories of …


The Towering Inferno: Art, Policy, And Legacy, Charles R. Jennings Jan 2025

The Towering Inferno: Art, Policy, And Legacy, Charles R. Jennings

Publications and Research

The Christian Regenhard Center for Emergency Response Studies, leveraging the expertise of its faculty, staff, Advisory Board and colleagues, has consistently programmed activities focused on high-rise fire safety. The upcoming 50th anniversary of the film The Towering Inferno was an inspiration.

We decided this would be more lighthearted and less purely technical than many of our events. We wanted to consider both the film, and use it to reflect on the state of fire safety in tall buildings in New York City.

Of course it does not escape us that the topic of fire safety is a serious one, …


Modeling Neighborhoods As Fuel For Wildfire, Bryce Alan Young Jan 2025

Modeling Neighborhoods As Fuel For Wildfire, Bryce Alan Young

Graduate Student Theses, Dissertations, & Professional Papers

Wildfire models drive billions of dollars in risk mitigation efforts. However, the modeling community currently lacks a representative fuelscape on which to base simulations of fire spread in the built environment and the wildland-urban interface (WUI) where vegetation and structures act together as fuel for wildfire. This thesis advances wildfire risk modeling by addressing the underdeveloped representation of the built environment in existing frameworks. By identifying inconsistencies in how structure and defensible space features are defined and used across empirical studies, predictive indices, and fire spread models, this research lays the groundwork for standardized modeling approaches and feature selection (Chapter …


Lara : A Light And Anti-Overfitting Retraining Approach For Unsupervised Time Series Anomaly Detection, Feiyi Chen, Zhen Qin, Mengchu Zhou, Yingying Zhang, Shuiguang Deng, Lunting Fan, Guansong Pang, Qingsong Wen Jan 2025

Lara : A Light And Anti-Overfitting Retraining Approach For Unsupervised Time Series Anomaly Detection, Feiyi Chen, Zhen Qin, Mengchu Zhou, Yingying Zhang, Shuiguang Deng, Lunting Fan, Guansong Pang, Qingsong Wen

Research Collection School Of Computing and Information Systems

Most of current anomaly detection models assume that the normal pattern remains the same all the time. However, the normal patterns of web services can change dramatically and frequently over time. The model trained on old-distribution data becomes outdated and ineffective after such changes. Retraining the whole model whenever the pattern is changed is computationally expensive. Further, at the beginning of normal pattern changes, there is not enough observation data from the new distribution. Retraining a large neural network model with limited data is vulnerable to overfitting. Thus, we propose a Light Anti-overfitting Retraining Approach (LARA) based on deep variational …


Power To Liquid And Hydrogen Use For Saf Production; A Policy And Techno-Economic Overview For Aviation​, Eva Maleviti Jan 2025

Power To Liquid And Hydrogen Use For Saf Production; A Policy And Techno-Economic Overview For Aviation​, Eva Maleviti

Publications

What is Sustainable Development: The development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

1. Environmental Sustainability

2. Social Sustainability

3. Economic Sustainability


Investigation Of A Busemann Intake At Negative Angle Of Attack, Mark E. Noftz, Andrew N. Bustard, Nicholas J. Bisek, Thomas J. Juliano, Joseph S. Jewell Jan 2025

Investigation Of A Busemann Intake At Negative Angle Of Attack, Mark E. Noftz, Andrew N. Bustard, Nicholas J. Bisek, Thomas J. Juliano, Joseph S. Jewell

Publications

A high-speed, shape-transitioned, inward-turning intake was tested in Purdue’s Boeing/AFOSR Mach 6 Quiet Tunnel. The inlet model, called the Indiana Inlet (INlet), had a total contraction ratio of 4.68:1 and a design point of Mach 6 at 0° angle of attack. The model was outfitted with a suite of high-frequency pressure transducers, and the external flowfield was imaged with high-speed schlieren photography. The INlet was tested under low freestream disturbance levels for a variety of freestream unit Reynolds numbers and at-4° angle of attack. An unsteady shockwave near the leading edge of the inlet forebody, indicative of boundary layer separation, …


Improving The Operator-Swarm Dynamic Under Mental Fatigue Constraints In Search And Rescue Operations, Jordan Morrow Jan 2025

Improving The Operator-Swarm Dynamic Under Mental Fatigue Constraints In Search And Rescue Operations, Jordan Morrow

Masters Theses

"Human-robot applications that allow for work to be done remotely are largely dependent on the lassitude of the operators. The exhaustion of these operators is a result of work completion and duration. Previous research attempts to evaluate the impact on reaction by quantiying human weariness. This paper examines how human weariness affects the human-robot dynamic in UAV-assisted search and rescue missions. An explanation of the connection between mental exhaustion and operator responsiveness over prolonged durations is provided by the search and rescue operations using UAV swarms (SAROUS) model. Through the use of artificial intelligence, SAROUS is modernized. This allows the …


Implication And Applications Of Machine Learning On Biomedical Images, Jason Hagerty Jan 2025

Implication And Applications Of Machine Learning On Biomedical Images, Jason Hagerty

Doctoral Dissertations

Medical imaging ranges in modality including computer tomography imaging, x-ray imaging, digital microscopy, and macro-focus dermoscopy images. The latter two modalities are the focus of the presented work.

To perform a diagnostic evaluation on the captured dermoscopy image, it begins with what is usually a labor-intensive operation that requires an expert to perform the initial segmentation for localizing a region of interest (ROI). Once that ROI is obtained, a physician with years of training and experience will observe biological markers that can be used to visually differentiate whether a lesion is benign or malignant. A similar process is used for …


Novel Nano-Formulations Based On Flash Nanoprecipitation For Ocular Drug Delivery, Lin Qi Jan 2025

Novel Nano-Formulations Based On Flash Nanoprecipitation For Ocular Drug Delivery, Lin Qi

Doctoral Dissertations

Effective ocular drug delivery has always been a challenge for clinical and research. Although many nanotechnology-based formulations have been developed and showed great potential in ocular drug delivery, this is far from enough to meet clinical requirements. These studies aimed at the design and synthesis of novel nanoparticles using multi-inlet vortex mixer (MIVM) to improve ocular drug delivery efficiency. The first project involves packaging two different anti-glaucoma drugs, brimonidine (BM) and betaxolol (BX), into solid drug nanoparticles (SDNs) by MIVM, which can achieve both functions, reducing aqueous humor production and promoting aqueous humor efflux. The studies demonstrate that the SDNs …


Data-Driven Mulitiscale Modeling Of Electrochemical Transport, Non-Linear Electrical Contact, And Additive Manufacturing Processes, Emmanuel Olugbade Jan 2025

Data-Driven Mulitiscale Modeling Of Electrochemical Transport, Non-Linear Electrical Contact, And Additive Manufacturing Processes, Emmanuel Olugbade

Doctoral Dissertations

The growing demand for high-efficiency energy systems and advanced manufacturing technologies requires predictive frameworks that link atomic-scale physics with engineering-scale performance. This dissertation develops a unified multiscale modeling approach that integrates molecular dynamics, density functional theory, finite-element analysis, and machine learning to connect structure, transport, and performance across materials and processes. Depending on the interactions involved, the framework employs loose coupling for parameter transfer, tight coupling for two-way feedback, and hybrid coupling where machine-learning surrogates accelerate high-fidelity simulations while retaining physical interpretability. In electrochemical systems, an XGBoost-enhanced single-particle model reproduces P2D-level electrolyte potential dynamics at roughly one-hundredth the computational cost, …


Characterization And Modeling Of Properties Of Unsaturated And Partially Damaged Cement-Based Materials, Rezwana Binte Hafiz Jan 2025

Characterization And Modeling Of Properties Of Unsaturated And Partially Damaged Cement-Based Materials, Rezwana Binte Hafiz

Doctoral Dissertations

"Transport properties, governing the resistance of cement-based materials to harmful substances are essential considerations for long-term performance. This study addressed the often-overlooked dimension of transport properties in unsaturated cement-based materials, crucial as most concrete structures face variable environmental conditions, leading to partial saturation. A two-scale model was introduced, enhancing our comprehension of transport properties in conditions reflecting real-world scenarios. Empirical correlation representing bulk paste characteristics was established, facilitating the upscaling of properties to mortar and concrete. The model was extended to predict the transport properties of mortar as well.

Environmental factors can contribute to the degradation of cement-based materials, with …


Additive Manufacturing Of Multifunctional Materials And Composites, John Michael Pappas Jan 2025

Additive Manufacturing Of Multifunctional Materials And Composites, John Michael Pappas

Doctoral Dissertations

"This research focused on developing fundamental knowledge of process-material interactions for additive manufacturing of multifunctional materials that are highly desirable in high-tech industries for potential weight and space savings. Multifunctional materials are very sensitive to defects, which severely hinder performance. Thus, defect formation was systematically studied to develop strategies and methodologies to efficiently fabricate high-performance materials and composites. Blown-powder-based laser additive manufacturing of transparent spinel ceramics was investigated to reduce porosity and cracking, defects that hindered transparency and mechanical properties. A systematic study of processing parameters revealed that laser power and powder flow rate had the largest effects on defect …


Exploring The Feasibility Of Innovative Integration Of Phase Change Materials For Thermo-Adaptive Asphalt Pavements, Farshad Saberi Kerahroudi Jan 2025

Exploring The Feasibility Of Innovative Integration Of Phase Change Materials For Thermo-Adaptive Asphalt Pavements, Farshad Saberi Kerahroudi

Doctoral Dissertations

"Current research examined the feasibility and efficiency of employing phase change materials (PCMs) in asphalt pavement materials to result in thermo-adaptive asphalt pavement. The PCM was introduced to the asphalt materials in three different scales, including asphalt binder, asphalt mastic, and asphalt mixture. After investigating asphalt at different scales, mix blending method was found as the easiest method without any complexity to mix asphalt binder with PCM. The testing results could reveal an improvement in the high temperature performance of asphalt binder without sacrificing the low temperature performance with the presence of PCM and Gilsonite. Also, introducing PCM to asphalt …


การแปลและตรวจสอบคุณภาพของแบบสอบถามวัดจิตสำนึกความยั่งยืนฉบับภาษาไทย และการศึกษาระดับจิตสำนึกของเยาวชนไทย, สุทธิแดน พลวัติจรัสวัฒน์ Jan 2025

การแปลและตรวจสอบคุณภาพของแบบสอบถามวัดจิตสำนึกความยั่งยืนฉบับภาษาไทย และการศึกษาระดับจิตสำนึกของเยาวชนไทย, สุทธิแดน พลวัติจรัสวัฒน์

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในช่วงหลายปีที่ผ่านมา ประเด็นด้านความยั่งยืนได้รับความสำคัญเพิ่มมากขึ้นทั้งในระดับโลกและระดับประเทศ เนื่องจากสังคมกำลังเผชิญปัญหาสิ่งแวดล้อม สังคม และเศรษฐกิจที่ทวีความซับซ้อน ส่งผลให้การเสริมสร้างความตระหนักรู้และพฤติกรรมที่สอดคล้องกับการพัฒนาที่ยั่งยืน โดยเฉพาะในกลุ่มเยาวชน กลายเป็นองค์ประกอบสำคัญในการขับเคลื่อนเป้าหมายการพัฒนาที่ยั่งยืน (SDGs) ของประเทศ เครื่องมือวัดจิตสำนึกความยั่งยืน เช่น Sustainability Consciousness Questionnaire (SCQ) ได้รับการพัฒนาและใช้ในหลายประเทศ อย่างไรก็ตาม ในบริบทประเทศไทยยังไม่มีฉบับภาษาไทยที่ผ่านกระบวนการแปลและตรวจสอบคุณภาพเชิงประจักษ์อย่างเป็นระบบ จึงจำเป็นต้องพัฒนาเครื่องมือที่มีความถูกต้อง เหมาะสม และใช้ได้จริงกับเยาวชนไทยการศึกษานี้มีวัตถุประสงค์ 3 ประการ ได้แก่(1) แปลและตรวจสอบคุณภาพของแบบสอบถามวัดจิตสำนึกความยั่งยืนฉบับภาษาไทย (2) เปรียบเทียบความสอดคล้องและความคู่ขนานของโครงสร้างการวัดระหว่างเครื่องมือต้นฉบับและฉบับภาษาไทย (3) ศึกษาระดับจิตสำนึกความยั่งยืนของเยาวชนไทยอายุ 18–19 ปีในมิติของความรู้ เจตคติ และพฤติกรรมด้านความยั่งยืน การศึกษาใช้แนวทางการพัฒนาเครื่องมือ โดยดำเนินงาน 2 ขั้นตอน ได้แก่(1) การแปลและตรวจสอบคุณภาพของ SCQ ฉบับยาวและฉบับสั้นผ่านกระบวนการแปลสองทิศทาง (forward–backward translation) การตรวจสอบความตรงเชิงเนื้อหาโดยผู้เชี่ยวชาญ 3 ท่าน และการทดสอบความเข้าใจของกลุ่มตัวอย่างเป้าหมายด้วย Cognitive Debriefing (2) การศึกษาระดับจิตสำนึกความยั่งยืนของเยาวชนไทยจำนวน 800 คน ผลการตรวจสอบคุณภาพของเครื่องมือพบว่า แบบสอบถามฉบับภาษาไทยมีค่าดัชนีความสอดคล้อง (IOC) ระหว่าง 0.66–1.00 อยู่ในเกณฑ์ดีมาก และมีค่าความเที่ยงภายใน (Cronbach’s Alpha) เท่ากับ 0.90 สำหรับฉบับยาว และ 0.93 สำหรับฉบับสั้น ผลการวิเคราะห์องค์ประกอบเชิงยืนยัน (CFA) แสดงให้เห็นว่าโมเดลทั้งสองรูปแบบมีความสอดคล้องกับข้อมูลเชิงประจักษ์ โดยฉบับยาวมีค่า χ² = 577, df = 1068, χ²/df = 0.54, CFI = 0.93, RMSEA = 0.03 และฉบับสั้นมีค่า χ² = 160, df = 54, χ²/df = 2.96, CFI = …


Automated Infinite Combos Detection System For Collectible Card Game, Amornpong Trakarnkulphun Jan 2025

Automated Infinite Combos Detection System For Collectible Card Game, Amornpong Trakarnkulphun

Chulalongkorn University Theses and Dissertations (Chula ETD)

In Collectible Card Games, resources management is one of the most effective strategy. However, there are some combinations of cards which produce unlimited resources called infinite combos. Too-cheap infinite combos that can be played early in the game break game environment, because the player who executes the combo immediately wins. To solve the problem, game designers usually restrict a part of the combos from being played. Due to the large number of cards in the card pool, it is difficult to search for these combos and solve this problem before a release date of a card set. This research aims …


Effect Of Solvent On Nonanoic And Azelaic Acids Yield Enhancement From Oxidative Cleavage Of Oleic Acid, Chakreeya Santhadklang Jan 2025

Effect Of Solvent On Nonanoic And Azelaic Acids Yield Enhancement From Oxidative Cleavage Of Oleic Acid, Chakreeya Santhadklang

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study investigates the effect of solvent choice on the oxidative cleavage of oleic acid using hydrogen peroxide (H2O2) as the oxidant, with a focus on improving the yields of nonanoic acid (NA) and azelaic acid (AA). Solvent selection was found to play a critical role due to polarity differences between the reactants and oxidants. tert-Butanol was unsuitable because of its low boiling point, leading to the evaluation of higher-boiling solvents including guaiacol, acetoin, ethyl lactate, and isobutyric acid. Guaiacol and acetoin exhibited undesirable chemical reactivity, while ethyl lactate resulted in low yields due to hydrogen bonding with intermediate species. …


Experimental Investigation Of Surfactant Impact On Surfactant-Oil-Brine System For Surfactant Enhanced Oil Recovery, Chananpat Worpattanaluk Jan 2025

Experimental Investigation Of Surfactant Impact On Surfactant-Oil-Brine System For Surfactant Enhanced Oil Recovery, Chananpat Worpattanaluk

Chulalongkorn University Theses and Dissertations (Chula ETD)

Enhanced Oil Recovery (EOR) is a vital technique for improving hydrocarbon extraction efficiency from mature or low-production reservoirs. Among various EOR methods, chemical flooding, particularly surfactant-based EOR, has gained attention due to its ability to reduce interfacial tension (IFT), to alter rock wettability, and to mobilize trapped oil. However, the performance of surfactant systems is highly sensitive to reservoir salinity, temperature, and rock-fluid interactions, leading to surfactant precipitation, adsorption losses, and interfacial tension reduction. Therefore, understanding the effects of salinity, surfactant concentration, and the role of scale inhibitors on the physicochemical stability of surfactant-oil-brine systems is essential for designing robust …


Enhancing Performance Of Lstm For Water Level Forecasting In Lower Mekong River With Feature Selection Strategy, Chanreng Sey Nhim Jan 2025

Enhancing Performance Of Lstm For Water Level Forecasting In Lower Mekong River With Feature Selection Strategy, Chanreng Sey Nhim

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study addresses key research gaps, including the lack of systematic feature selection, structured hyperparameter optimization, and comprehensive long-term and cross-location performance evaluation in the Lower Mekong River Basin to enhance the water level forecasting performance. The research has utilized a Vanilla Long Short-Term Memory (LSTM) network trained on 22 years of historical water level data from the Mekong River Commission (MRC) and 16 localization meteorological features from Open-Meteo. The methodology uses Grid Search optimization for hyperparameter tuning and employs the Spearman rank correlation coefficient as a filter feature selection technique to identify relevant input variables and minimize redundancy. Performance …


Efficient Photocatalytic Hydrogen Evolution Via Novel Syntheses Of Srtio₃/G-C₃N₄ Heterojunction Photocatalysts, Chiramet Thatsanakunlaphan Jan 2025

Efficient Photocatalytic Hydrogen Evolution Via Novel Syntheses Of Srtio₃/G-C₃N₄ Heterojunction Photocatalysts, Chiramet Thatsanakunlaphan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Strontium titanate/graphitic carbon nitride (SrTiO3/g-C3N4) heterojunctions are widely used as photocatalysts. However, traditional multistep synthesis methods for these photocatalysts often involve complexity, long processing times, and high energy consumption. To address these issues, a systematic comparison of various simplified synthesis approaches was conducted, emphasizing the influence of synthesis parameters on the structural properties and hydrogen evolution performance. Six comparative studies were conducted to illustrate the roles of solvent choice, thermal post-treatment, and synthesis route. Results showed that ethylene glycol consistently produced more active photocatalysts than ethanol in both one-pot and two-step solvothermal methods. Non-calcined samples exhibited superior hydrogen evolution activity …


Quality Of Life Prediction For Driving Route Planning System Using Image Recognition And Deep Learning, Intouch Prakaisak Jan 2025

Quality Of Life Prediction For Driving Route Planning System Using Image Recognition And Deep Learning, Intouch Prakaisak

Chulalongkorn University Theses and Dissertations (Chula ETD)

Assessing travel-related Quality of Life (QoL) is a significant challenge due to its reliance on subjective human perception, which is difficult to measure. Traditional studies are often constrained by the limited scope of costly, manual data collection. The significant contribution of this research is the introduction of a new framework that can analyze tourist perception on a large and systematic scale. The novelty of this work lies in the utilization of Google Street View (GSV) as a large-scale visual data source, coupled with the use of a sequence-based model to analyze travel routes, which allows for the simulation of the …


Improving The Availability Of Aluminium Sheath Extrusion Machines In The Cable Industry, Jirathana Vasinyont Jan 2025

Improving The Availability Of Aluminium Sheath Extrusion Machines In The Cable Industry, Jirathana Vasinyont

Chulalongkorn University Theses and Dissertations (Chula ETD)

Aluminium sheath extrusion machines (AL Seamless) play a critical role in the production of high-voltage cables, ensuring the integrity and quality of electrical transmission infrastructure. However, after commissioning such machines at PD Company was fraught with challenges, including frequent breakdowns, limited machine availability, and production inefficiencies. The underlying issues stemmed from inadequate standard operating procedures (SOPs), insufficient knowledge transfer during commissioning, and suboptimal maintenance practices. To address these challenges, this research applied structured methodologies, including Failure Mode and Effects Analysis (FMEA) to identify critical failure points and root causes, and Total Productive Maintenance (TPM) to improve operational reliability. Knowledge transfer …


Out-Of-Domain Tuberculosis Detection From Chest X-Ray Images Using Meta Learning With Soft Labels, Kanokphat Jinanarong Jan 2025

Out-Of-Domain Tuberculosis Detection From Chest X-Ray Images Using Meta Learning With Soft Labels, Kanokphat Jinanarong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Automated tuberculosis screening from chest x-ray images could greatly benefit regions with limited medical resources. However, currently available methods could not handle this problem well due to the difference in chest x-ray images in each region caused by the difference in machine and demographics, the possible noise in the available labels, and other reasons. We therefore propose a new machine learning algorithm that could detect tuberculosis with great accuracy on any other data sources by learning from completely different data sources. We used a model-agnostic meta-learning together with a soft label approach, utilizing the meta-gradient to dynamically adjust the soft …


A Study On The Impact Of Superconducting Fault Current Limiteron Arc Flash Hazard In An Industrial System, Kittipong Anantanasap Jan 2025

A Study On The Impact Of Superconducting Fault Current Limiteron Arc Flash Hazard In An Industrial System, Kittipong Anantanasap

Chulalongkorn University Theses and Dissertations (Chula ETD)

The increasing integration of distributed generation raises short-circuit current levels, which lead to concerns about equipment overheating, insulation deterioration, and system stability issues. The Resistive Superconducting Fault Current Limiter (R-SCFCL) offers an effective solution by dynamically increasing circuit impedance during faults without affecting normal operation. However, its integration may alter the fault-clearing time of the protection system, which is crucial for arc-flash safety. This study evaluates the impact of R-SCFCL integration on arc-flash hazards in an industrial power system, utilizing DIgSILENT PowerFactory and calculations based on IEEE 1584. Results indicate that while the R-SCFCL effectively reduces arcing current, the incident …


Vehicle Routing Problem With Time Constraint From Multiple Origins To Selective Destinations By Using Genetic Algorithm, Manocha Kruetet Jan 2025

Vehicle Routing Problem With Time Constraint From Multiple Origins To Selective Destinations By Using Genetic Algorithm, Manocha Kruetet

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis addresses the vehicle routing problem with time constraints from multiple origins to selective destinations by using a genetic algorithm for efficient path planning. The focus is on optimizing field collection and repossession activities in the financial industry to enhance operational efficiency and customer satisfaction. The proposed approach integrates two main components: a tailored genetic algorithm for multi-objective optimization and a graph neural network for precise travel time estimation. The genetic algorithm is designed to minimize total travel distance or travel time and balance the workload among field collectors, while the graph neural network provides travel time estimates to …


Development Of Defective Tiox And Hfo2-X For Efficient Visible-Light-Driven Photocatalytic Degradation Of Organic Pollutants, Mohammad Rahim Pour Jan 2025

Development Of Defective Tiox And Hfo2-X For Efficient Visible-Light-Driven Photocatalytic Degradation Of Organic Pollutants, Mohammad Rahim Pour

Chulalongkorn University Theses and Dissertations (Chula ETD)

The development of efficient photocatalysts capable of operating under visible light is critical for addressing persistent organic contaminants in wastewater. In this thesis, two complementary strategies are presented that exploit defect engineering and heterojunction construction to enhance charge separation, light absorption, and pollutant degradation. In the first study, titanium oxide quantum dots with a high density of oxygen vacancies were dispersed onto H-Beta zeolite supports via a sono-deposition approach. The zeolite substrate not only enabled uniform distribution of sub-5 nm TiOx particles, but also promoted pre-accumulation of cationic dyes, which significantly improved their subsequent oxidation. Structural and spectroscopic analyses confirmed …


Feasibility Study Of Utilization Of Calcium-Based Material For Integrated Methane Dry Reforming And Co2 Absorption-Mineralization Processes, Nattanan Watcharasawat Jan 2025

Feasibility Study Of Utilization Of Calcium-Based Material For Integrated Methane Dry Reforming And Co2 Absorption-Mineralization Processes, Nattanan Watcharasawat

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis investigates an integrated absorption-mineralization and dry reforming of methane (IAM-DRM) loop. The aim is to demonstrate the feasibility of using CaCO3 derived from amine scrubbing both as a CO2 sink and as reactive support for in situ Ni activation during DRM, while simultaneously regenerating the MEA solvent and calcium material for repeated use. CO2 absorption of monoethanolamine (MEA) yield equilibrium loadings of 0.66 mol CO2 mol-1 MEA with regenerated MEA maintaining identical performance. Mineralization on CaCl2 and Ca(OH)2 produced different phases product. Temperature programmed DRM demonstrated that mineralized CaCO3 can activate Ni in situ and sustain CH4 conversion. …