Operational Research Commons^™

Classification And Analysis Of Twitter Bot And Troll Accounts, Callan P. Mccormick

Theses and Dissertations

This research trains, tests, and analyzes bot and troll classification models using publicly available, open source datasets. Specifically, it applies decision tree, random forest, feed forward neural networks, and long-short term memory neural networks with hyperparameters tuned via designed experiment to five labeled bot datasets created between 2011 and 2020 and one dataset labeling state-sponsored disinformation accounts or trolls. The first three models utilize account profile features, while the last model applies natural language processing techniques, specifically GloVe embedding, to analyze a user’s Tweet history. Results indicate that the random forest model outperforms the other three models with an average …

An Analysis Of Aircraft Maintenance Leading Indicator Metrics To Unit-Level Aircraft Availability Rates, William C. Hardy

Theses and Dissertations

The purpose of this research is to improve the usefulness of data that is already collected within aircraft maintenance organizations to better identify trends, and outliers, and possibly better explain relationships between leading and lagging indicator metrics. Specifically, this graduate research paper sought to answer two research questions addressing what aircraft maintenance metrics significantly impact aircraft availability, and how to measure those to understand which metrics impact aircraft availability most. The research questions were answered through a comprehensive literature review, and the use of multiple linear regression analysis on data from two specific aircraft maintenance organizations from the same location. …

Optimal Control Of Precision Airdrop Trajectories Using Direct Collocation And Analytical Methods, Edward J. Maxwell

Theses and Dissertations

The work herein investigates the preliminary designs of an optimal navigation controller for a scalable cylindrical airdrop system controlled with grid fins in planar motion. Precision airdrop capabilities are desired for a range of military and humanitarian missions. Fielded airdrop systems have not met desired performance objectives, particularly regarding accuracy. Direct collocation and analytical methods were utilized to solve the optimal control problem for the grid fin controlled precision airdrop system examined in this work. The optimal control problem was comprised of two phases: controlled descent and parachute descent. Minimum and maximum ranges for the system under varying wind fields …

Inducing Sparsity Within High-Dimensional Remote Sensing Modalities For Lightning Prediction, Grace E. Metzgar

Theses and Dissertations

The uncertainty of lightning constantly threatens many weather-sensitive fields where the slightest presence of lightning can endanger valuable personnel and assets. The consequences of delaying operations have incited the research of methods that can accurately predict the location of future lightning strikes from the current weather conditions. High-dimensional remote sensing modalities contain information capable of detecting significant patterns and intensities within storms that could indicate the presence of lightning. This thesis induces sparsity into convolutional neural networks (CNNs) and remote sensing modalities through a combination of regularization and tensor decomposition techniques to call attention to sparse features that are most …

An Approximate Dynamic Programming Approach For Solving An Air Combat Maneuvering Problem With Directed Energy Weapons, Elisha A. Palm

Theses and Dissertations

Performing within visual range (WVR) air combat involves the execution of complex air maneuvers and rapid sequential decision making. The complexity of these decisions can increase even further when including additional weapon capabilities. The advancement of unmanned autonomous vehicle technology and weapon capabilities can help combat the hindrance that comes with human limitations. Autonomous unmanned combat aerial vehicles (AUCAVs) and the implementation of advanced weapon capabilities such as Directed Energy Weapons (DEWs) can prove to be vital in a WVR air combat context. This derives the question – Can AUCAV’s possess the proper artificial intelligence and weapon capabilities to attain …

Information System Availability Status And Its Impact On Customer Wait Times, Joshua A. Cramer

Theses and Dissertations

The Military Personnel Flight relies on Air Force Information Systems, specifically the Defense Enrollment Eligibility and Reporting System (DEERS), to manage the personnel records. When DEERS experiences a failure, then the operational ability of the Military Personnel Flight is affected. This study aims at identifying the impact Air Force information system’s availability status has on customer wait times using linear regression.

The Aerial Refueling Asset Basing And Assignment Problem, Camryn E. Deames

Theses and Dissertations

With growing tensions in the European theatre and Indo-Pacific theatre, the constraints of aerial refueling impede the missions of Air Mobility Command and USTRANSCOM in their execution of both the National Security Strategy and National Defense Strategy. Introducing and integrating semi-autonomous aerial refueling aircraft is a logical next step due to advantages in endurance, survivability, runway requirements, and fuel offloading capacity. This research frames the Aerial Refueling Asset Basing and Assignment Problem with two model approaches: a baseline model and a fuel shuttle concept model. Whereas the former model considers instances with only manned refuelers or only semi-autonomous refuelers, the …

U.S. Army Force Structure Optimization And Sufficiency Analysis, Francis P. Gargin

Theses and Dissertations

The United States Army perpetually deploys rotational forces across the globe in support of the National Security Strategy. These forces meet a set of discrete mission demands over an extended time period before redeploying, modernizing, and preparing for the next deployment. The U.S. Army now utilizes the Regionally Aligned Readiness and Modernization Model to execute these cyclical stages for unit deployments. Specific emphasis is placed on aligning forces against a Geographic Combatant Command, which allows units to build readiness and lethality oriented towards the same series of threats, physical terrain, and civilian considerations. This research provides an Integer Programming model …

Hierarchical Federated Learning On Healthcare Data: An Application To Parkinson's Disease, Brandon J. Harvill

Theses and Dissertations

Federated learning (FL) is a budding machine learning (ML) technique that seeks to keep sensitive data private, while overcoming the difficulties of Big Data. Specifically, FL trains machine learning models over a distributed network of devices, while keeping the data local to each device. We apply FL to a Parkinson’s Disease (PD) telemonitoring dataset where physiological data is gathered from various modalities to determine the PD severity level in patients. We seek to optimally combine the information across multiple modalities to assess the accuracy of our FL approach, and compare to traditional ”centralized” statistical and deep learning models.

Designing A Counter-Iads Drone Swarm: Using Evolution To Evaluate Combat Assumptions Underpinning Drone Swarm Target Assignment, Olin H. Kennedy

Theses and Dissertations

The original research goal was to combine the best techniques in the drone swarm literature and model a functional combat drone swarm that conducts a Suppression of Enemy Air Defense (SEAD) mission. However, the body of literature regarding Drone Swarm Target Assignment (DSTA) does not model enemy counteraction and assumes that the drones’ targets are compliant against destruction. Therefore, a model of enemy counteraction against drone swarms is developed, and Novel DSTA (NDSTA) is proposed to respond to the weaknesses of the current DSTA. Both methods of target assignment are combined with a tunable trajectory generation model, and the performance …

Air Force Cadet To Career Field Matching Problem, Ian P. Macdonald

Theses and Dissertations

This research examines the Cadet to Air Force Specialty Code (AFSC) Matching Problem (CAMP). Currently, the matching problem occurs annually at the Air Force Personnel Center (AFPC) using an integer program and value focused thinking approach. This paper presents a novel method to match cadets with AFSCs using a generalized structure of the Hospitals Residents problem with special emphasis on lower quotas. This paper also examines the United States Army Matching problem and compares it to the techniques and constraints applied to solve the CAMP. The research culminates in the presentation of three algorithms created to solve the CAMP and …

Advancing Autonomous Swarm Behavior In A Simulated Anti-Access Area Denial (A2ad) Environment, Chad P. Macwilkinson

Theses and Dissertations

Advancements in modern IADS have bolstered A2AD environments and subsequently degraded the advantages that the Air Force once held, prompting a call to reform the nature of warfare in order to challenge these threats. A solution is weapon swarming technology, which has the ability to overwhelm IADS by engagement of a large numbers of low-cost, but lethal air assets that have autonomous functionalities. This research proposes the application of a four dimensional framework for autonomy to a swarm of cruise missiles. A virtual A2AD environment of two opposing forces is constructed using the AFSIM, wherein a manned bomber seeks to …

Simulating Autonomous Drone Swarm Behaviors In An Anti-Access Area Denial (A2ad) Environment, Alexander L. Martinez

Theses and Dissertations

Army senior military leaders are invested in acquiring modernized aerial platforms and equipment to augment the U.S. Army’s ability to overcome A2AD threats imposed by modern IADS. A prominent element of this modernization effort is the employment of autonomous drones to defeat IADS threats while minimizing risk to Army Soldiers. This research utilizes a framework for classifying the levels of autonomous capability along three dimensions: the ability to act alone, the ability to cooperate, and the ability to adapt. A virtual combat model, created using the AFSIM, simulates the engagement between an enemy IADS and a friendly formation comprised of …

The U.S. Army Officer-To-Unit Assignment Problem, Andrea L. Phillips

Theses and Dissertations

Every two to three years, U.S. Army officers must change duty stations, which entails a selection process based on preferences. Currently, officers are assigned to units using a stable-marriage algorithm. Two impracticalities occur within this process. First, officers are required to submit strictly ranked preferences, not allowing indifference among units. Second, the stable-marriage algorithm does not give flexibility to alternative priorities. This research focuses on two modifications to the current model. First, a mixed integer program is created that allows the user, U.S. Army Human Resources Command, to consider other priorities: unit preferences and maximum officer disappointment. Second, generated data …

Simulation And Analysis Of Dynamic Threat Avoidance Routing In An Anti-Access Area Denial (A2ad) Environment, Dante C. Reid

Theses and Dissertations

This research modeled and analyzed the effectiveness of different routing algorithms for penetration assets in an A2AD environment. AFSIM was used with different configurations of SAMs locations and numbers to compare the performance of AFSIM’s internal zone and shrink algorithm routers with a Dijkstra algorithm router. Route performance was analyzed through computational and operational metrics, including computational complexity, run-time, mission survivability, and simulation duration. This research also analyzed the impact of the penetration asset’s ingress altitude on those factors. Additionally, an excursion was conducted to analyze the Dijkstra algorithm router’s grid density holding altitude constant to understand its impact on …

Analysis And Optimization Of Contract Data Schema, Franklin Sun

Theses and Dissertations

agement, development, and growth of U.S Air Force assets demand extensive organizational communication and structuring. These interactions yield substantial amounts of contracting and administrative information. Over 4 million such contracts as a means towards obtaining valuable insights on Department of Defense resource usage. This set of contracting data is largely not optimized for backend service in an analytics environment. To this end, the following research evaluates the efficiency and performance of various data structuring methods. Evaluated designs include a baseline unstructured schema, a Data Mart schema, and a snowflake schema. Overall design success metrics include ease of use by end …

Probability Of Agreement As A Simulation Validation Methodology, Matthew C. Ledwith

Theses and Dissertations

Determining whether a simulation model is operationally valid requires the rigorous assessment of agreement between observed functional responses of the simulation model and the corresponding real world system or process of interest. This research seeks to extend and formulate the probability of agreement approach to the operational validation of simulation models. The first paper provides a methodological approach and an initial demonstration which leverages bootstrapping to overcome situations where one’s ability to collect real-world data is limited. The second paper extends the probability of agreement approach to account for second-order heteroscedastic variability structures and establishes a weighted probability of agreement …

Factors Influencing Users’ Attitudes Towards Using Brain Computer Interface (Bci) For Non Medical Uses: An Application Of The Technology Acceptance Model (Tam), Yichin Wu, Leila Halawi

National Training Aircraft Symposium (NTAS)

While brain-computer interfaces (BCI) are gaining popularity in assisting people with illnesses, there is also increased technical research on incorporating BCI into healthy people’s lives. So far, not much research has focused on user attitudes, although some research has pointed out privacy and trust issues. Understanding potential users’ attitudes, expectations, and concerns early in the technology development stage is crucial for the novelty's success. For this reason, this study aims to understand the general publics’ attitude towards BCI for nonmedical uses using the technology acceptance model (TAM). The study will offer insights into how external factors including technology optimism, familiarity, …

The Sensitivity Of A Laplacian Family Of Ranking Methods, Claire S. Chang

HMC Senior Theses

Ranking from pairwise comparisons is a particularly rich subset of ranking problems. In this work, we focus on a family of ranking methods for pairwise comparisons which encompasses the well-known Massey, Colley, and Markov methods. We will accomplish two objectives to deepen our understanding of this family. First, we will consider its network diffusion interpretation. Second, we will analyze its sensitivity by studying the "maximal upset" where the direction of an arc between the highest and lowest ranked alternatives is flipped. Through these analyses, we will build intuition to answer the question "What are the characteristics of robust ranking methods?" …

A Holistic Work System Approach To Creating Flow During Transactional Work, Steven Clapp

Electronic Theses and Dissertations, 2020-2023

Psychological flow is a positive mental state where one is so fully concentrated in a challenging task that self-consciousness falls away, time seems to stand still, and the reward is the experience of meeting the challenge. Previous research on flow in the workplace has been performed on how to create conditions to promote its occurrence in workers, to describe its attendant individual and organizational benefits, and to measure it through self-reported means and physiologically. Such research has been focused on creative endeavors (such as the arts, sports, medicine, teaching), where individuals have high agency over the execution of activities needed …

Understanding Outgroup Aversion Effects On Innovation Adoption And Polarization In Network Environments, Bruce G. Miller

Graduate Thesis and Dissertation 2023-2024

Individuals' decisions to adopt an innovation can be influenced by the group identity of previous adopters or non-adopters in their social network. Previous research in innovation diffusion considered initial innovators and word-of-mouth imitator effects using analytical models. Simulations and agent-based models have been developed to address the heterogeneity of decision makers and the non-linearity of the process. A further refinement modeled adoption based on networks of social relationships between potential decision makers, analogous to the spread of disease on networks. In addition, adoption or non-adoption of some innovations has been characterized as a means of signaling identification with or aversion …

Understanding Workforce Agility At Nasa Kennedy Space Center, Ledlyne H. Vazquez

Graduate Thesis and Dissertation 2023-2024

This study aims to define workforce agility via a literature review and a conducted research survey of the Kennedy Space Center (KSC) Engineering workforce. The survey results will help us determine the workforce agility of the KSC engineering team and understand what has allowed them to transition from the Space Shuttle Program to the new Exploration Ground System (EGS) program. Structural Equation Modeling was used to develop a model of relationships to test the hypotheses. The results show that organizational practices and psychological empowerment significantly support workforce agility. The implications of this study for understanding the characteristics of workforce agility …

Stochastic Optimization To Reduce Aircraft Taxi-In Time At Igia, New Delhi, Rajib Das, Saileswar Ghosh, Rajendra Desai, Pijus Kanti Bhuin, Stuti Agarwal

International Journal of Aviation, Aeronautics, and Aerospace

Since there is an uncertainty in the arrival times of flights, pre-scheduled allocation of runways and stands and the subsequent first-come-first-served treatment results in a sub-optimal allocation of runways and stands, this is the prime reason for the unusual delays in taxi-in times at IGIA, New Delhi.

We simulated the arrival pattern of aircraft and utilized stochastic optimization to arrive at the best runway-stands allocation for a day. Optimization is done using a GRG Non-Linear algorithm in the Frontline Systems Analytic Solver platform. We applied this model to eight representative scenarios of two different days. Our results show that without …

Ant Colony-Based Approach For Solving An Unmanned Aerial Vehicle Routing Problem, Youssef Harrath Dr., Jihene Kaabi Dr.

Research & Publications

Waste management issues are affecting the economic and environmental aspects of modern societies. Thus, growing the interest of academic and industrial research and development in optimizing the process of waste management. As these issues greatly impact human health and environmental aspects and impose a threat, hazardous waste management requires even much more attention. The problem studied in this research is a variant of the vehicle routing problem using an unmanned aerial vehicle (UAV). The focus of this research is on planning the routes for waste collection and disposal using a UAV. The aim is to collect all the waste as …

The Need For International Ai Activities Monitoring, Parviz Partow-Navid, Ludwig Slusky

Journal of International Technology and Information Management

This paper focuses primarily on the need to monitor the risks arising from the dual-use of Artificial Intelligence (AI). Dual-use AI technology capability makes it applicable for defense systems and consequently may pose significant security risks, both intentional and unintentional, with the national and international scope of effects. While domestic use of AI remains the prerogative of individual countries, the unregulated and nonmonitored use of AI with international implications presents a specific concern. An international organization tasked with monitoring potential threats of AI activities could help defuse AI-associated risks and promote global cooperation in developing and deploying AI technology. The …

Determinants Of Continuance Intention To Use Mobile Wallets Technology In The Post Pandemic Era: Moderating Role Of Perceived Trust, Shailja Tripathi

Journal of International Technology and Information Management

The Covid-19 pandemic amplified the volume and importance of mobile payments using digital wallets and placed a basis for their continued adoption. The objective of the study is to formulate and test a comprehensive model by integration of the technology acceptance model (TAM) and expectation confirmation model (ECM) with the addition of three constructs, namely perceived trust, perceived risk, and subjective norm, to identify the determinants of continuance intention to use mobile wallets. Questionnaire-based survey method was used to gather the data from 550 users having experience using mobile wallets for more than six months. The data were analyzed using …

การประเมินราคาเครื่องจักรโดยใช้เทคนิคเดลฟายและกระบวนการวิเคราะห์เชิงลำดับชั้น, นัจนันท์ เลี่ยงทรชน

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อหาเกณฑ์การประเมินราคาเครื่องจักรที่เหมาะสม สำหรับการประเมินราคาเครื่องจักรตามแนวทางการเปรียบเทียบราคาตลาด โดยใช้กระบวนการวิเคราะห์เชิงลำดับชั้นในการกำหนดเกณฑ์และน้ำหนักความสำคัญ และใช้เทคนิคเดลฟายในการหาระดับของแต่ละเกณฑ์ การดำเนินงานวิจัยได้เริ่มจาก 1) ทำการสำรวจเกณฑ์การประเมินราคา 2) การสอบถามเชิงลึกถึงเกณฑ์ที่เกี่ยวข้องจากนักประเมินอาชีพ 3) สร้างผังโครงสร้างการตัดสินใจเชิงลำดับชั้นสำหรับการหาเกณฑ์ในการประเมินราคา 4) วิเคราะห์น้ำหนักความสำคัญจากกระบวนการวิเคราะห์เชิงลำดับชั้น 5) วิเคราะห์ระดับคุณสมบัติของเกณฑ์จากเทคนิคเดลฟาย 6) เปรียบเทียบผลการประเมินราคาเครื่องจักรด้วยวิธีเปรียบเทียบราคาตลาด งานวิจัยนี้ได้เลือกเครื่องกลึงโลหะ เครื่องผสมยาง ห้องเย็น เครื่องฉีดพลาสติก และเครื่องสีข้าว มาเป็นตัวแทนของกลุ่มอุตสาหกรรมในงานวิจัย โดยสร้างผังโครงสร้างการตัดสินใจเชิงลำดับชั้นการประเมินราคาประกอบด้วยเกณฑ์หลักทั้งหมด 6 เกณฑ์ เกณฑ์รอง 15 เกณฑ์ ผลจากการหาน้ำหนักความสำคัญของเกณฑ์ พบว่าเกณฑ์หลักที่มีน้ำหนักความสำคัญสูงในทุกเครื่องจักร คือ สภาพเครื่องจักร และประสิทธิภาพ ส่วนเกณฑ์รอง คือ สภาพความพร้อมใช้งาน เมื่อนำเกณฑ์หลักและเกณฑ์รองมาพิจารณาร่วมกัน ทำให้ได้เกณฑ์การประเมินราคาเครื่องจักรทั้งหมด 17 เกณฑ์ ที่มีค่าน้ำหนักความสำคัญของแต่ละเกณฑ์ในแต่ละเครื่องจักรแตกต่างกัน โดยน้ำหนักความสำคัญของเกณฑ์จะสัมพันธ์วัตถุประสงค์ของเครื่องจักรนั้นๆ อาจปรับเปลี่ยนมีความแตกต่างกันตามหน้าที่ของเครื่องจักร จากนั้นใช้เทคนิคเดลฟายในการหาระดับของแต่ละเกณฑ์ ซึ่งนักประเมินทั้งกลุ่มมีความเห็นชอบต่อการแบ่งระดับของแต่ละเกณฑ์ดังกล่าว เมื่อนำเกณฑ์ที่ได้นี้ไปใช้ในการประเมินมูลค่าของเครื่องกัดแนวตั้งและเครื่องฉีดพลาสติกเพื่อเป็นตัวอย่างการสร้างเกณฑ์ในงานวิจัยนี้ พบว่าสามารถลดความแตกต่างของมูลค่าเครื่องกัดแนวตั้งและเครื่องฉีดพลาสติก ของนักประเมินแต่ละคนได้ถึง 83.05% และ 97.56% ตามลำดับ

ตัวแบบการวางแผนจัดโปรโมชันลดราคาหลายช่วงเวลา สำหรับสินค้าร้านค้าปลีก, ชนิกานต์ ทั่งทอง

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อพัฒนาแบบจำลองทางคณิตศาสตร์ สำหรับการวางแผนจัดโปรโมชันลดราคาหลายช่วงเวลาสำหรับสินค้าในร้านค้าปลีกกรณีศึกษา ซึ่งปัจจุบันวางแผนการจัดโปรโมชัน โดยใช้ผู้มีประสบการณ์ ทำให้การจัดโปรโมชันแต่ละครั้งใช้เวลานาน ดังนั้นผู้วิจัยจึงนำเสนอแบบจำลองโปรแกรมเชิงเส้นจํานวนเต็มไบนารี ในการแก้ปัญหาภายใต้ข้อจำกัดต่างๆ โดยมีวัตถุประสงค์เพื่อเพิ่มผลกำไรรวมสูงที่สุด งานวิจัยนี้ใช้ตัวแบบการประมาณการยอดขายแบบลอการิทึม ในการประมาณการยอดขายรายเดือนและจำแนกกลุ่มสินค้าตามค่าความยืดหยุ่นของอุปสงค์ต่อราคา ผลการวิจัยพบว่าการจัดโปรโมชันโดยพิจารณารวมทุกกลุ่มกำไรพร้อมกัน สามารถให้ผลกำไรรวมได้ดีที่สุด โดยพัฒนาผลกำไรรวมเพิ่มขึ้น 1,194,517.75 บาท หรือคิดเป็น 3.94 เปอร์เซ็นต์ เมื่อเทียบกับการจัดโปรโมชันของร้านค้าปลีกกรณีศึกษาในปัจจุบัน และใช้เวลาประมวลผลได้เหมาะสม นอกจากนั้นผู้วิจัยได้ใช้วิธีจำลองสถานการณ์มอนติคาร์โล เพื่อจำลองสถานการณ์ค่าสัมประสิทธ์ของความยืดหยุ่นของอุปสงค์ต่อราคาเพื่อใช้ในการศึกษาผลกระทบของปัจจัยต่างๆ ผลจากการทดลองเชิงคำนวณพบว่าปัจจัยความยืดหยุ่นของอุปสงค์ต่อราคา เป็นปัจจัยที่สำคัญที่ต่อการเลือกประเภทความลึกของการลดราคาที่เหมาะสม นอกจากนั้นผู้วิจัยได้ทำการพัฒนาและสร้างแม่แบบในโปรแกรมเอ็กเซล เพื่อใช้ในการรับข้อมูลเพื่อส่งต่อไปยังโปรแกรม IBM ILOG CPLEX Optimization จากนั้นก็ทำการแปลงข้อมูลผลลัพธ์ของตัวแปรตัดสินใจกลับมาใน Excel ให้อยู่ในรูปแบบตารางที่ง่ายต่อการนำไปใช้งาน

Managing The Success Of Tpm Deployment & Sustainment In The Automotive Industry, Kevin Gembel

Wayne State University Dissertations

Maintenance has assumed increased importance in manufacturing as companies look for ways to gain an advantage over their competitors. The philosophical benefits of jointly implementing Total Productive Maintenance (TPM) programs in concert with other lean and quality programs have been discussed in the manufacturing literature. However, there is an absence of real-life implementation studies for objective assessment. To the best of our knowledge, this is the very first longitudinal study to investigate the implementation of TPM programs at a large global OEM across several regions and facilities using objective data collected across all key functions and outcomes. We study a …

Mitigating Supply Chain Disruptions In Retail Discount Department Stores, Anthony T. Patton

Walden Dissertations and Doctoral Studies

Supply chain disruptions can have adverse effects on business outcomes. Retail industry supply chain leaders are concerned with supply chain disruptions because supply chain disruptions can lead to dissatisfied customers and loss of profits. Grounded in game theory, the purpose of this multiple case study was to explore strategies four retail industry supply chain leaders in Northern Illinois and Northwest Indiana implemented to mitigate the effects of supply chain disruptions. Data were collected using semistructured virtual interviews with four retail industry supply chain leaders and a review of company documents. Through thematic analysis, four themes emerged: (a) choosing appropriate inventory …