Engineering Commons^™

Improved Minimum Variance Channel Estimation Techniques For Ofdm Systems, Kwame S. Ibwe

Tanzania Journal of Engineering and Technology (TJET)

Orthogonal frequency division multiplexing (OFDM) systems face challenges in channel estimation due to noise, variability, and the doubly dispersive nature of wireless channels, which degrade performance. To address these challenges, a multichannel minimum variance double dispersive channel estimator is proposed. The method employs a hybrid approach that combines subspace and minimum variance techniques, optimizing the filter bank output power under a signal-to-noise ratio (SNR) constraint. This design preserves the desired signal while effectively suppressing disturbances, achieving robust performance with reduced computational complexity compared to existing methods. Simulation results demonstrate that the proposed estimator outperforms subspace and asymptotic methods in terms …

Effects Of Thermal Shock Protection Methods On Pressure Measurements In A Rapid Compression Machine, Myeji Materego

Tanzania Journal of Engineering and Technology (TJET)

The study investigates the impact of thermal shock protection methods on pressure measurements in Rapid Compression Machines (RCMs). It focuses on the performance of various pressure transducers, specifically 601A, 701A, 6061B, and 7005, under atmospheric initial conditions. The research emphasizes the importance of mounting techniques and coatings, revealing their significant effects on pressure trace accuracy. Special mounting adaptors for the pressure transducers were designed and manufactured, this enabled simultaneous measurements for all transducers to be made in a single compression stroke. Instantaneous pressure within combustion chamber was measured when air was compressed in RCM from initial pressure and temperatures of …

Efficient Operation Of Direct Coupled Solar Home Pv System: A Case Of Solar Home Pv System Installed In Dodoma, Tanzania, Sarah P. Ayeng'o

Tanzania Journal of Engineering and Technology (TJET)

Direct coupled Photovoltaic (PV) system is a common topology among most of the off-grid communities in the world. This topology has less components hence resulting in low investment costs. However, it suffers much losses when battery operating voltage is far from maximum power point voltage of PV modules. This scenario can be attributed by different factors such as; variation in solar radiation, load profile and temperature. Efficient operation of these systems is required in order to reduce losses. Usually in direct coupled system, PV modules are connected in parallel with batteries through a charge controller hence making PV output to …

Can An Llm Use Work System Axioms When Describing Work Systems For Requirements Analysis?, Steven Alter

Business Analytics and Information Systems

This research-in-progress paper presents part of an ongoing project related to using LLMs for describing, analyzing, and designing work systems (including information systems). General axioms that apply to any non-trivial WS or IS might provide a path toward new tools and methods. This paper identifies 24 work system axioms that extend earlier research. They are organized in five categories: 1) system in context, 2) system operation, 3) system goals and goal attainment, 4) system uncertainties, and 5) system-related change. The axioms potentially address the challenge of helping business and IS/IT professionals understand and collaborate around systems in organization. This preliminary …

Nonconvex Optimization Methods Under Inexact Information, Dat Ba Tran

Wayne State University Dissertations

This thesis focuses on the design and convergence analysis of algorithms for solving nonconvex optimization problems under inexact first-order information. We introduce Inexact Reduced Gradient (IRG) methods for general smooth functions and Inexact Gradient Descent (IGD) methods for $\mathcal{C}^{1,1}_L$ functions with relative and absolute errors. Additionally, we develop Inexact Proximal Point and Inexact Proximal Gradient methods for weakly convex functions. Our methods improve the performance of standard inexact proximal point methods, inexact proximal gradient methods, and inexact augmented Lagrangian methods by approximately 2.5 to 10 times in terms of iteration complexity for image processing tasks. Moreover, we propose new derivative-free …

Crime Theory Informed Agent-Based Modeling For Crime Prediction And Patrolling Route Optimization, Shohreh Moradi

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Crime reduction remains a global priority, demanding both accurate modeling of criminal dynamics and efficient allocation of scarce policing resources. To address these needs, this study presents a two‐fold framework that (1) simulates street‐level crime patterns using an agent‐based model (ABM) grounded in Routine Activity Theory (RAT), Rational Choice Theory (RCT), and Crime Pattern Theory (CPT), and (2) optimizes patrol routing through a time-dependent, multi‐visit mixed‐integer linear programming (MILP) formulation.

In the first component, we integrate real‐world crime, environmental, and census data to reproduce realistic offender, citizen, and Police behaviors, capturing where and when robbery, burglary, and larceny occur across …

The Association Between The Multidimensional Evaluation Of Attitudes Toward Security Recommendations And The Intention Of Following Those Recommendations, Miguel A. Toro-Jarrin, Pilar Pazos, Miguel A. Padilla

Engineering Management & Systems Engineering Faculty Publications

This study focused on the attitudes toward security recommendations as determinants of compliance with these recommendations in the workplace. It aimed to determine whether attitudes toward an overall concept (security recommendations in organizations) are associated with Information Security (IS) actions. We also examined the relationship between various dimensions of attitudes toward security recommendations and IS actions that follow these recommendations. We conducted a national survey of American workers. Six hundred and eighty-two responses were retained. We also collected demographic data to explore their moderating role in the relation between predictors and IS action-intention. The survey included four workplace scenarios and …

Leveraging Intrinsic Properties For Classification Of Coal Seams Towards Spontaneous Combustion Proclivity And Predicting Susceptibility Using Machine Learning: Smart And Sustainable Mining Approach, Siddhartha Agarwal, Pradeep K. Gautam, Yuhao Zou, Rishabh Dwivedi, Durga C. Panigrahi, Cihan H. Dagli, A. Singh

Engineering Management and Systems Engineering Faculty Research & Creative Works

Mine fires and other hazards caused by spontaneous coal combustion are a pervasive and longstanding issue in Jharia coalfields, India. This study proposes a novel approach to classify coal seams based on their propensity to spontaneous combustion using the intrinsic properties of 30 coal samples from different seams. This method eliminates the need for expensive and time-consuming experimental determinations of susceptibility indices (SI) such as crossing point temperature (CPT), critical air blast (CAB), and differential thermal analysis (DTA). All clustering models, viz. hierarchical, k-means, and multidimensional scaling, aptly classify coal seams into three categories: highly risky, medium risky, and low …

Integrating Data Management Plans Into The Unified Architecture Framework Standards Views, Cansu Yalim, Holly A. H. Handley

Engineering Management & Systems Engineering Faculty Publications

System Architecting translates an operational concept into a model of the system to be realized. There is a need for a Data Management Plan (DMP) to be included in the overall system engineering process with the advent of Digital Engineering. Data longevity, accessibility, and integrity can all be improved throughout the system's lifecycle by a well-defined DMP. System engineers use an architecture framework to arrange the system data into several sets of viewpoints. Incorporating a DMP at this point specifies the procedures for gathering, storing, retrieving, and maintaining data to ensure that all interested parties have access to current, correct …

An Impact Analysis Of The 15-Year Capital Program And Budget In The City Of Philadelphia, James K. Lewis

West Chester University Doctoral Projects

Abstract

In order to serve its constituents, the City of Philadelphia has established numerous public service departments and respective public goods in terms of departments facilities and other structures to provide public service. The key departments include the Police Department, Fire Department, Health Department, Libraries, and Parks and Recreation. Additionally, there are departments established to build, renovate, maintain, the public goods provided by the City of Philadelphia in order to achieve successful stewardship of the facilities. In order to carry out facilities stewardship of its public goods, the City has a long-term capital program and budget that utilizes borrowed capital …

Fetal Acidosis Prediction Using Attention Enhanced Convolutional Neural Networks, Anusha Adhikari

Masters Theses

This study explores the integration of spectral mixtures of fetal heart rate (FHR) and uterine contraction (UC) signals to enhance the prediction of fetal acidosis, utilizing the CTU-CHB dataset. Several classification models were trained using two distinct oversampling techniques and inputs, demonstrating that models incorporating spectral mixtures significantly outperform those using raw signals. These models, particularly when combined with convolutional neural networks (CNNs) and attention mechanisms, achieved a notable F1-score of 0.98, with the highest model achieving an area under the Receiver Operating Characteristic (ROC) curve of 0.95. The research employs a variety of techniques including short-time Fourier transform and …

Long Short-Term Memory (Lstm) -Based Neural Network Model For Optimizing Composite Manufacturing Process Using Autoclave, Sourav P. Bolar

Masters Theses

The combination of high pressure and controlled heat plays a critical role in ensuring the uniform curing of composite materials, leading to parts with superior mechanical properties. In this study, three composite samples of IM7/CYCOM 5320-1, each cut into 12x12-inch squares, were placed in an autoclave at three different locations, spaced 6 inches apart. Sixteen thermocouples were randomly distributed across the setup to monitor the curing process as the autoclave temperature was systematically ramped up and down while maintaining constant pressure, creating a fully controlled curing environment. The primary objective was to optimize the curing locations to reduce machine runtime …

Application Of Artificial Intelligence Techniques To Improve Leadership Decision Making With Uncertainty, Michael David Parrish

Doctoral Dissertations

"Every good leader is a good manager, but not every good manager is a good leader. The difference between the leader and the manager is critical decision-making. Today’s decision-making environment is characterized as Volatile, Uncertain, Complex, and Ambiguous (VUCA). With the exponential increase in the technical capabilities of systems, the human has become the weakest link in the use of such systems. To remain relevant, good leaders must continuously adapt to new advances in technology and processes.

The research contributions of this work provide several unique and novel solutions for leaders to utilize artificial intelligence tools to improve and optimize …

Enhanced Load Detection With Data-Driven Appliance Signatures Using Mixed Integer Linear Programming In Non-Intrusive Load Monitoring, Marina Materikina

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Despite the numerous research studies and interest in the non-intrusive load monitoring (NILM) area to improve energy efficiency, the problem of accurate and precise disaggregation of electrical devices has not been solved yet. The goal of our research is to build a method with a focus on higher accuracy on complex state-based appliances, which most approaches struggle to detect due to their power signal complexity and low consumption. Our approach is NILM with data-driven signatures (DS), with the ability to potentially predict power usage over time that would work great for suitable applications such as demand response, anomaly detection, and …

Enhancing The Mechanical Properties Of Sla 3d-Printed Bio-Resin From Linseed Oil Using Cellulose And Lignin Biopolymers, Chukwunonso A. Ikedionu

College of Graduate Studies: Theses & Dissertations

Abstract

This research explores the development of bio resin from linseed oil by the process of epoxidation and acrylation to produce acrylated epoxidized linseed oil (AELO). Lignin and cellulose biopolymers were added as reinforcement at varying weight fractions of 1 wt.%, 2.5 wt.%, and 5 wt.%, and their mechanical performance was compared against pure AELO. The formulations were printed using an Elegoo SLA 3D printer to create standardized test specimens like tensile bars, compression cylinders, and hardness blocks, which were all prepared according to the ASTM testing standard.

The results indicate that reinforcement effects depend on both filler type and …

Transplant Surgeon Fuzzy Associative Memory (Tsfam): Model For Capturing Surgeon Perspective, Rachel Dzieran, Cihan H. Dagli, Robert J. Marley

Engineering Management and Systems Engineering Faculty Research & Creative Works

AI-driven healthcare decision-making is multi-faceted, requiring complex logic to adapt to evolving policies and societal demands. Effective change implementation by healthcare providers and multidisciplinary organ transplant teams depends on adaptive decision-making. The proposed Transplant Surgeon Fuzzy Associative Memory (TSFAM) model introduces a novel approach to Human-AI Teaming, keeping human expertise central while dynamically adjusting to changing requirements. TSFAM employs fuzzy logic to manage imperfect data and human ambiguity, integrating the transplant surgeon perspective with the AI deep learning decision-making tool, creating a resilient solution in this critical domain. By embedding adaptive capabilities into the architecture, TSFAM exemplifies the adaptability of …

Understanding The Determinants Of Blockchain Adoption: An Empirical Study, Amarpreet Kohli, Nihar Kumthekar, Piyush Shah, Rebecca Jauch

Journal of International Technology and Information Management

Blockchain technology (BT) has the potential to enhance security and robustness of transactions through a distributed ledger bookkeeping process. This study employs technology-organization-environment (TOE) framework and threat-rigidity theory (TRT) to examine whether perceived disruption caused by COVID-19 pandemic significantly impacted the adoption of BT, and inclination to adopt BT in the US. The COVID-19 pandemic provided a unique backdrop, as it affected businesses across all industries, sizes, and geographies. Results show a non-significant effect of perceived pandemic disruption on the current stage of BT adoption and intention to adopt BT. However, disruption readiness positively influences the current stage of BT …

Molecular Dynamics-Based Two-Dimensional Simulation Of Powder Bed Additive Manufacturing Process For Unimodal And Bimodal Systems, Yeasir Mohammad Akib, Ehsan Marzbanrad, Farid Ahmed

Manufacturing & Industrial Engineering Faculty Publications

The trend of adapting powder bed fusion (PBF) for product manufacturing continues to grow as this process is highly capable of producing functional 3D components with micro-scale precision. The powder bed’s properties (e.g., powder packing, material properties, flowability, etc.) and thermal energy deposition heavily influence the build quality in the PBF process. The packing density in the powder bed dictates the bulk powder behavior and in-process performance and, therefore, significantly impacts the mechanical and physical properties of the printed components. Numerical modeling of the powder bed process helps to understand the powder spreading process and predict experimental outcomes. A two-dimensional …

Fault Tree Analysis For Robust Design, Jonathan Degroff, Gene Jean-Win Hou

Mechanical & Aerospace Engineering Faculty Publications

The objective of this research is to incorporate system failure into a robust design formation and solution process. The system failure referred to here will be built using fault tree analysis (FTA), which will take all lower-level failure events into consideration. Two examples are investigated here. One will directly treat the probabilities of the basis events as design variables, The other will be formulated in five different models: deterministic design optimization, the reliability index-based, the “and” gate-based, the “or” gate-based and the “inhibit” gate-based robust design. Their corresponding optimization solutions will be compared with each other. The post-optimality analysis of …

Mitigating Out-Of-Plane Fiber Waviness In Afp Laminates With Tow-Gaps Via Selective Placement Of Thermoplastic Veils, Ahmadreza Ravangard, Kuthan Celebi, Sergii G. Kravchenko, Oleksandr G. Kravchenko

Mechanical & Aerospace Engineering Faculty Publications

Fiber tow-gaps and overlaps formed during the Automated Fiber Placement (AFP) process pose a significant challenge by introducing non-uniform composite morphologies, often characterized by resin-rich regions and fiber waviness. These defects occur as deposited fibers sink into the gap regions during consolidation, with gap geometry determined during path planning. Such morphological inconsistencies can compromise structural reliability by initiating premature failure, particularly through localized out-of-plane waviness and resin accumulation. This study investigates the integration of high melting temperature thermoplastic veils, specifically polyetherimide (PEI), into fiber tow-gaps as a method to prevent ply sinking and reduce fiber waviness on both internal and …

Introducing Sustainable Development Goals In College Curricula: A Way Forward, Christy Ashley, Jason D. Oliver, Hillary Leonard

Markets, Globalization & Development Review

The commentary proposes a blueprint to help guide curriculum innovations, partnerships, and teaching interventions that incorporate the United Nations sustainable development goals (SDGs) into the curriculum. It suggests the utilization of AACSB’s Societal Impact Canvas with Ancona et al.’s (2007) Leadership Capabilities (Sensemaking, Relating, Visioning, Inventing) to provide a blueprint for mission-aligned SDG integration at a local level. It provides an illustrative example from the University of Rhode Island (USA), where the focus is on the Blue Economy. It aims to provide practical guidance for how a college or university can efficiently organize to gain stakeholder input that helps enhance …

Systematic Analysis Of Fatal Collisions Between Mobile Equipment And Pedestrian Workers To Inform The Use Of Proximity Detection Devices, Damien Burlet-Vienney, François Gauthier, Chantal Gauvin

Articles dans des actes de congrès

Context.

Collisions between mobile industrial equipment and pedestrian workers (PWs) are a major occupational health and safety concern, particularly on construction sites (e.g., during earth-moving operations). The use of driver aids, such as proximity warning devices designed to alert workers and drivers of potential collisions, is a growing and constantly developing avenue of prevention (e.g., AI-enhanced cameras; RFID tags). However, structured feedback to guide the implementation of these technologies on mobile equipment remains rare (e.g., technology choice, installation and settings).

Objective/Methodology.

 In this context, a systematic analysis of all fatal accident reports related to this issue for the province of …

How Inclusive Are Degree Programs In Operations Research And Analytics In The U.S.?, Michael P. Johnson Jr., Tayo Fabusuyi, Elham Hesari, Salina Chu

Public Policy and Public Affairs Faculty Publication Series

Academic programs in colleges and universities in the United States have increasingly embraced principles of equity and inclusion to support student success and diversity within professions. Innovations in diversity, equity, and inclusion (DEI) in university programs require baseline data on students, faculty and administrators, curricula, and programmatic support. A review of data shows that underrepresented groups in the US workforce have limited visibility in operations research and analytics. A review of DEI-related research reveals some relevant insights including a gap in studies specific to operations research and analytics.

To provide evidence in support of DEI initiatives in OR/analytics, we describe …

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 …

Risk Management For Irrigation Water Pumping Project In Myin Gyan District, Myanmar, Ye Lin Aung

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study evaluates risk and performance management in the Si Mee Khon irrigation water pumping project in Myin Gyan District, Myanmar. Although intended to supply irrigation to 5,000 acres of farmland, the project has fallen short of planned targets. By Q3 2025, 53.62% of the budget had been spent while only 44% of the intended coverage had been completed, signalling significant delays and cost inefficiencies. The research identifies and prioritises key risks, assesses their effects on schedule and cost performance, and proposes mitigation strategies. A mixed-method approach was used, combining interviews with twenty MOALI officials and quantitative analysis based on …

การวิเคราะห์ความสามารถในการขับขี่และพฤติกรรมจากความเหนื่อยล้าโดยใช้สัญญาณภาพ, ภาสวิชญ์ บุญนุช

Chulalongkorn University Theses and Dissertations (Chula ETD)

อาการเหนื่อยล้ายังคงเป็นประเด็นด้านความปลอดภัยที่สำคัญในกลุ่มผู้ขับรถบรรทุก ซึ่งมักจะส่งผลให้ระดับความสามารถในการขับขี่ลดลงและเพิ่มความเสี่ยงต่อการเกิดอุบัติเหตุ การศึกษาในครั้งนี้นำเสนอแนวทางการใช้แบบจำลองการเรียนรู้ของเครื่อง (Machine Learning) โดยมีการรวมข้อมูลเหตุการณ์การเกิดพฤติกรรมของผู้ขับขี่ที่ตรวจจับได้จากระบบ AI Camera และข้อมูลด้านประชากรศาสตร์และลักษณะการทำงาน เพื่อทำนายระดับความสามารถในการขับขี่ที่ลดลงที่มีสาเหตุมาจากอาการเหนื่อยล้า โดยทำการศึกษาจากข้อมูลจำนวน 600 วัน ซึ่งประกอบไปด้วยผู้ขับขี่จำนวน 105 คน โดยแบ่งระดับความสามารถในการขับขี่ออกเป็น 3 ระดับ ได้แก่ ความสามารถปกติ ความสามารถลดลง และความสามารถที่มีความเสี่ยงสูง โดยสังเกตจากพฤติกรรมการตอบสนองขณะขับขี่ การวิเคราะห์จะพิจารณาการรวมข้อมูลด้านประชากรศาสตร์และลักษณะการทำงาน วิธีการพัฒนาเกณฑ์ในการระบุระดับความสามารถในการขับขี่ กรอบเวลาในการสังเกตอาการเหนื่อยล้า และคุณภาพของข้อมูลเชิงพฤติกรรม โดยใช้แบบจำลองการเรียนรู้ของเครื่องภายใต้กรอบเวลาในการสังเกตที่แตกต่างกันก่อนเกิดที่ระดับความสามารถในการขับขี่ลดลง ผลการศึกษาแสดงให้เห็นว่าปัจจัยด้านประชากรศาสตร์และปัจจัยที่แสดงลักษณะการทำงานช่วยเพิ่มความแม่นยำในการทำนาย โดยสำหรับการศึกษานี้ แบบจำลองชนิด LightGBM ให้ผลการทำนายที่ดีที่สุดที่ค่าความแม่นยำ 90% ภายใต้เงื่อนไขเหตุการณ์ที่ผ่านการตรวจสอบและใช้กรอบเวลา 8 นาที ซึ่งสะท้อนให้เห็นถึงประโยชน์ของการใช้กรอบเวลาสั้นในการตรวจจับอาการเหนื่อยล้า การวิเคราะห์ความสำคัญของแต่ละปัจจัย (Feature Importance) พบว่า การหาว การปฏิบัติงานต่อเนื่องเกิน 4 ชม. และการหลับตา เป็นตัวบ่งชี้ทางพฤติกรรมที่สำคัญที่สุดตามลำดับ ในขณะที่อายุ การยกของก่อนขับรถ ช่วงเวลาในการทำงาน ประสบการณ์ในการทำงาน เป็นปัจจัยด้านประชากรศาสตร์และการทำงานที่มีอิทธิพลต่อการลดลงของระดับความสามารถในการขับขี่ ผลการศึกษานี้ชี้ให้เห็นถึงความสำคัญของการรวมข้อมูลเหตุการณ์ที่ผ่านการตรวจสอบเข้ากับลักษณะเฉพาะของผู้ขับขี่ และกรอบเวลาในการสังเกตอาการเหนื่อยล้าที่เหมาะสม เพื่อใช้ในการประเมินระดับความสามารถที่ลดลงที่มีสาเหตุจากอาการเหนื่อยล้าได้อย่างมีประสิทธิภาพในงานขนส่ง

การเปรียบเทียบขนาดของรอยฝ่าเท้าที่ได้จากเครื่องพิมพ์รอยฝ่าเท้า 3 มิติ แบบพกพาและโฟมพิมพ์เท้า, วรัญญา รัตนสุมาวงศ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

ความแม่นยำของเครื่องมือใหม่ที่ถูกพัฒนามาใช้ทดแทนเครื่องมือเดิม เป็นปัจจัยสำคัญต่อความน่าเชื่อถือ ได้มีการพัฒนาเครื่องพิมพ์รอยฝ่าเท้า 3 มิติแบบพกพาเพื่อทดแทนการใช้โฟมพิมพ์เท้า และใช้ iPhone 12 mini เป็นอุปกรณ์สแกนรอยฝ่าเท้าเพื่อทดแทนเครื่อง 3D scanner เพื่อประเมินให้เห็นว่าสามารถนำเครื่องพิมพ์รอยฝ่าเท้า 3 มิติแบบพกพาและ iPhone 12 mini มาใช้ทดแทนได้ จึงได้มีการออกแบบการทดลองแบบ Randomized Complete Block Design (RCBD) โดยศึกษาปัจจัยของประเภทเครื่องมือที่ใช้พิมพ์รอยฝ่าเท้า ได้แก่ โฟมพิมพ์เท้า และ เครื่องพิมพ์รอยฝ่าเท้า 3 มิติ แบบพกพา และประเภทเครื่องสแกน 3 มิติ ได้แก่ 3D scanner และ iPhone 12 mini การทดสอบได้เก็บข้อมูลเท้า 18 ข้าง จากผู้เข้าร่วมวิจัย 9 คน โดยพิมพ์ลงบนเครื่องพิมพ์รอยฝ่าเท้า 3 มิติ แบบพกพาและโฟมพิมพ์เท้า และทำซ้ำ 3 ครั้ง รอยฝ่าเท้าที่ได้ถูกสร้างรูปร่างรอยฝ่าเท้าดิจิตอลด้วย iPhone 12 mini และ 3D scanner เพื่อเก็บข้อมูลตัวชี้วัดทั้ง 7 ตัว ได้แก่ ความกว้างรอยฝ่าเท้า ความยาวรอยฝ่าเท้า ความสูงรอยฝ่าเท้าในพื้นที่บริเวณอุ้งเท้า 4 ตำแหน่ง และความสูง Metatarsal head ที่ 3 จากผลการวิเคราะห์ทางสถิติแบบ Randomized Complete Block Design (RCBD) ที่ระดับความเชื่อมั่น 95% พบว่าตัวชี้วัดทั้ง 7 ตัว ของเครื่องพิมพ์รอยฝ่าเท้า 3 มิติ แบบพกพากับโฟมพิมพ์เท้าไม่มีความแตกต่างกันอย่างมีนัยสำคัญ และการใช้ iPhone 12 กับ 3D scanner ไม่มีความแตกต่างกันอย่างมีนัยสำคัญเช่นกัน ผลการวิจัยสรุปได้ว่า …

Optimal Control Of Queueing Systems With Error-Prone Servers, Junqi Hu, Sigrún Andradóttir, Hayriye Ayhan

Information Technology & Decision Sciences Faculty Publications

Consider a Markovian tandem line with finite intermediate buffers and an equal number of stations and servers. Servers are flexible but noncollaborative, so that a job can be processed by at most one server at any time. When a job is being processed, it can be damaged and wasted depending on the proficiency of the server. We identify the dynamic server assignment policy that maximizes the long-run average throughput of the system with two stations and two servers. We find that the optimal policy is either a single or a double threshold policy on the number of jobs in the …

A System To Test Selective Directional Laser Melting Of 3d Printed Metal Surfaces, Daniel A. Marasco

Open Access Master's Theses

This thesis contains Controlled Unclassified Information (CUI). CUI has been removed from this copy of the thesis.

Machining-Induced Residual Stress Modeling Using Physics-Informed Neural Networks, Md Mehedi Hasan

Theses and Dissertations--Mechanical and Aerospace Engineering

Process-induced residual stress (RS) plays a critical role in determining the structural integrity, fatigue life, corrosion resistance, and dimensional stability of manufactured components. Tensile residual stress can be harmful to the machined workpiece by lowering fatigue strength, while compressive residual stress helps to prevent such issues. Therefore, accurate prediction and control of machining-induced residual stresses are essential for optimizing manufacturing processes and enhancing component performance. However, existing modeling approaches—empirical, analytical, and numerical—often have limited predictive accuracy, demand extensive calibration, or involve high computational costs. Traditional finite element analysis (FEA) provides modeling insights but is constrained by its high computational cost …