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Articles 49471 - 49500 of 196904

Full-Text Articles in Engineering

Residential Bathroom And Tile Shower Addition During Covid-19 Quarantine, Joseph Szillinsky Mar 2021

Residential Bathroom And Tile Shower Addition During Covid-19 Quarantine, Joseph Szillinsky

Construction Management

This paper outlines the design and construction of a new code compliant bathroom including: a low profile shower pan, ceramic-tile shower enclosure, and new plumbing piping and fixtures. One of the main objectives was to complete the new shower which would be easily accessible and maintenance free in order to support a local elderly couple. The selection of this project took place during the COVID-19 pandemic approximately nine months after California issued the first mandatory statewide Stay-at-Home Order. During the early design and development stages an opportunity to collaborate with a local trades-person was identified as well as the need …

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An Examination Of Potential Training Regression Recognition Algorithms For Pilot Training Next, Alex R. Gaines Mar 2021

An Examination Of Potential Training Regression Recognition Algorithms For Pilot Training Next, Alex R. Gaines

Theses and Dissertations

The initiative to reduce the Air Forces serious pilot shortage lead to the Pilot Training Next (PTN) program. Under PTN, student pilots progress at an individual rate while making increased use of simulator-based training resources. A previous thesis used data from the first PTN class to conceptualize and prototype a student training flight scheduler. This scheduler did not consider training events required to bring students back to achieved levels of performance if in fact that student performance had regressed. This thesis examines three classes of PTN student data to determine whether student regression in training progression can be detected. A …

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Improving Manufacturability And Reducing Cracking In Additively Manufactured Tungsten Alloys, Christopher P. Fassio Mar 2021

Improving Manufacturability And Reducing Cracking In Additively Manufactured Tungsten Alloys, Christopher P. Fassio

Theses and Dissertations

Additively Manufactured tungsten suffers from low () densities due to high concentrations of microcracks as the printed layers cool past tungsten's high ductile to brittle transition temperature. In this study, tungsten-rhenium and tungsten rhenium hafnium carbide compositions were evaluated on density and tensile strength. In addition to varying the compositions of each alloy, printing parameters and post-processing methods were also compared. Print parameters varied for all compositions on an MLab 200R C using included the laser scan strategy, hatch spacing, scan speed, laser power, and print bed material. Post processing techniques of the WRe compositions included hot isostatic pressing and …

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Optimizing Critical Values And Combining Axes For Multi-Axial Neck Injury Criteria, Ethan J. Gaston Mar 2021

Optimizing Critical Values And Combining Axes For Multi-Axial Neck Injury Criteria, Ethan J. Gaston

Theses and Dissertations

The Air Force employs ejection seats in its high-performance aircraft. While these systems are intended to ensure aircrew safety, the ejection process subjects the aircrew to potentially injurious forces. System validation includes evaluation of forces against a standard which is linked to the probability of injury. The Muti-Axial Neck Injury Criteria (MANIC) was developed to account for forces in all six degrees of freedom. Unfortunately, the MANIC is applied to each of the three linear input directions separately and applies different criterion values for each direction. These three separate criteria create a lack of clarity regarding acceptable neck loading, leading …

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An Empirical Analysis Of Dod Construction Task Order Performance, Adam B. Teston, Tyler S. Stout Mar 2021

An Empirical Analysis Of Dod Construction Task Order Performance, Adam B. Teston, Tyler S. Stout

Theses and Dissertations

Cost and schedule overrun plague over 50 of all construction projects, engendering diminished available funding that leads to deferred maintenance and impaired award ability for needed projects. Though existing research attempts to identify overruns sources, the results are inconclusive and frequently differ. Accordingly, this research reviews DoD construction contract data from the past ten years to identify the contract attributes of 79,894 projects that correlate with superior performance for use in future project execution. This research starts with creating a database that houses the largest single source of construction contract information. The research then evaluates the data to determine if …

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Supporting Space Domain Awareness Through The Development And Analysis Of Space Object Detection Algorithms Employed By Ground-Based Telescopes, Connor A. Paw Mar 2021

Supporting Space Domain Awareness Through The Development And Analysis Of Space Object Detection Algorithms Employed By Ground-Based Telescopes, Connor A. Paw

Theses and Dissertations

Detection algorithms are instrumental in maintaining space domain awareness, specifically in the observation, monitoring, and categorization of unknown space objects. State of the art detection algorithms utilize a matched filter or a spatial correlator on long exposure image data to make pixel-wise detection decisions. This thesis investigates the advantages and practical potential of two different post-processing detection algorithms that can be employed by ground-based telescopes. The first algorithm explored is based on a long exposure Fourier domain processing technique, while the second is centered around frame selection from a series of short exposure images. The results of the experiments performed …

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Characterizing Security Monitor And Embedded System Performance Across Distinct Risc-V Ip-Cores, Justin C. Tullos Mar 2021

Characterizing Security Monitor And Embedded System Performance Across Distinct Risc-V Ip-Cores, Justin C. Tullos

Theses and Dissertations

Embedded systems have seen a rapid integration into all forms of industry as they continue to shrink in size and cost. The increased demand has highlighted a need for secure systems that are robust to attacks and demonstrate reliable performance, especially if the system operation is time-critical. E orts to characterize the performance of secure systems have been obstructed either by proprietary restrictions or ineffective analysis. Proprietary technology limits a comprehensive validation of a system's security and the implications it might have on performance. Performance analysis that is disclosed often lacks sufficient statistical rigor needed for a complex system. A …

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Commuting Compositions For Quantum Circuit Reduction, Brenna R. Cole Mar 2021

Commuting Compositions For Quantum Circuit Reduction, Brenna R. Cole

Theses and Dissertations

Quantum circuit simplification improves program execution on quantum hardware by reducing error from prolonged environmental interaction and noisy gate operations. One simplification technique is template matching, which repeatedly conducts local optimization by replacing small sequences of gates within a circuit by optimized versions. Underlying this method is the problem of identifying sequences matching templates. This is challenging because some, but not all, gates can commute within a circuit. This means there may not be a subcircuit that matches a template in the original circuit specification, but a match may exist in an equivalent rearrangement of gates. In such cases, certain …

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Development Of A Testbed For Foot Mounted Based Pedestrian Dead Reckoning (Pdr) Systems, Jordan E. Eldridge Mar 2021

Development Of A Testbed For Foot Mounted Based Pedestrian Dead Reckoning (Pdr) Systems, Jordan E. Eldridge

Theses and Dissertations

Over the last several years of research into the field of Pedestrian Dead Reckoning (PDR), there have been varying degrees of success in providing a viable individual navigation system. The PDR solutions developed utilize everything from a single Inertial Measurement Units (IMU) to several IMUs with additional sensors. One specific PDR solution identified that by utilizing a micro-mechanical Inertial Measurement Unit (IMU) on each foot (along with the application of Zero Velocity Updates (ZUPT) and foot-to-foot range measurements) a reliable method of PDR tracking could be accomplished. Their study concludes that further evaluation is required for this foot-mounted solution to …

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A Cyber Threat Taxonomy And A Viability Analysis For False Injections In The Tcas, John W. Hannah Mar 2021

A Cyber Threat Taxonomy And A Viability Analysis For False Injections In The Tcas, John W. Hannah

Theses and Dissertations

This thesis provided background information on the Traffic Collision Avoidance System (TCAS). Additionally, the thesis developed a threat taxonomy for TCAS, resulting in the determination that a false injection attack presents the most comprehensive risk. Moreover, the thesis presents the development of a program to determine what ranges, altitudes, and relative bearings are most vulnerable to a false injection attack. The program includes test for all requirements of a successful false injection. Furthermore, the thesis presents an analysis of results and creates threat maps as situational awareness tools. Lastly, the thesis discusses potential solutions to the false injection attack, covers …

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Spatially Separable Blind Deconvolution Of Long Exposure Astronomical Imagery, Justin S. Lee Mar 2021

Spatially Separable Blind Deconvolution Of Long Exposure Astronomical Imagery, Justin S. Lee

Theses and Dissertations

In this thesis, a spatially separable blind deconvolution algorithm is demonstrated that achieves a significantly faster processing time and superior sensitivity when processing long-exposure image data of unresolvable objects from a ground-based telescope. The proposed approach takes advantage of the structure of the long exposure point spread functions radial symmetric characteristics to approximate it as a product of one dimensional horizontal and vertical intensity distributions. Objects at geosynchronous or geostationary orbit also can be well approximated as being spatially separable as they are, in general non-resolvable. The algorithms performance is measured by computing the mean-squared error compared with the true …

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Waste Collection Routing Problem: A Mini-Review Of Recent Heuristic Approaches And Applications, Yun-Chia Liang, Vanny Minanda, Aldy Gunawan Mar 2021

Waste Collection Routing Problem: A Mini-Review Of Recent Heuristic Approaches And Applications, Yun-Chia Liang, Vanny Minanda, Aldy Gunawan

Research Collection School Of Computing and Information Systems

The waste collection routing problem (WCRP) can be defined as a problem of designing a route to serve all of the customers (represented as nodes) with the least total traveling time or distance, served by the least number of vehicles under specific constraints, such as vehicle capacity. The relevance of WCRP is rising due to its increased waste generation and all the challenges involved in its efficient disposal. This research provides a mini-review of the latest approaches and its application in the collection and routing of waste. Several metaheuristic algorithms are reviewed, such as ant colony optimization, simulated annealing, genetic …

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Wind Blade Manufacturing For The Cal Poly Wind Power Club, Benjamin E. Thompson, Jake R. Lund, Claudia C. Angeles Mar 2021

Wind Blade Manufacturing For The Cal Poly Wind Power Club, Benjamin E. Thompson, Jake R. Lund, Claudia C. Angeles

Mechanical Engineering

The Cal Poly Wind Power Club is entering the 2021 Collegiate Wind Competition (CWC) in June. Last year, three senior project teams were assigned to collaborate and assist the club with the pitching mechanism, the rotor balancing, and the manufacturing process. As the manufacturing team, the goal of our project was to design a manufacturing process for the bladegeometry given. The manufacturing process was required to meet the team’s expectations and CWC’s performance requirements to place highly in the competition taking place in June 2021.These expectations included creating a manufacturing process that is repeatable and reliable for future competitions. The …

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Low-Cost Terrestrial Demonstration Of Autonomous Satellite Proximity Operations, Zackary R. Hewitt Mar 2021

Low-Cost Terrestrial Demonstration Of Autonomous Satellite Proximity Operations, Zackary R. Hewitt

Theses and Dissertations

The lack of satellite servicing capabilities significantly impacts the development and operation of current orbital assets. With autonomous solutions under consideration for servicing, the purpose of this research is to build and validate a low-cost hardware platform to expedite the development of autonomous satellite proximity operations. This research aims to bridge the gap between simulation and existing higher fidelity hardware testing with an affordable alternative. An omnidirectional variant of the commercially available TurtleBot3 mobile robot is presented as a 3-DOF testbed that demonstrates a satellite servicing inspection scenario. Reference trajectories for the scenario are generated via optimal control using the …

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Stereo Camera Calibrations With Optical Flow, Joshua D. Larson Mar 2021

Stereo Camera Calibrations With Optical Flow, Joshua D. Larson

Theses and Dissertations

Remotely Piloted Aircraft (RPA) are currently unable to refuel mid-air due to the large communication delays between their operators and the aircraft. AAR seeks to address this problem by reducing the communication delay to a fast line-of-sight signal between the tanker and the RPA. Current proposals for AAR utilize stereo cameras to estimate where the receiving aircraft is relative to the tanker, but require accurate calibrations for accurate location estimates of the receiver. This paper improves the accuracy of this calibration by improving three components of it: increasing the quantity of intrinsic calibration data with CNN preprocessing, improving the quality …

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Predicting F-16 Cause Code H Micap Hours Using Jmp Regression Analysis, Scott E. Carr Mar 2021

Predicting F-16 Cause Code H Micap Hours Using Jmp Regression Analysis, Scott E. Carr

Theses and Dissertations

Emergency demands for aircraft parts, MICAPs (Mission Impaired Capability Awaiting Parts) are one of the leading issues affecting mission capability supply rates for fighter aircraft. Cause code H MICAPS, those with a known demand level, but no supply available, are particularly troublesome and difficult to resolve. These MICAPS are due to failures by the supply chain to replenish stock levels within acceptable time limits. Numerous studies have identified a clear need for proactive measures to reduce MICAP hours. This would significantly improve aircraft availability. This study uses regression analysis implemented in JMP software to build models with a goal of …

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Application Of Game Theory Based Design To U.S. Space Systems, Benjamin C. Donohoo Mar 2021

Application Of Game Theory Based Design To U.S. Space Systems, Benjamin C. Donohoo

Theses and Dissertations

Modern defense systems are designed to static sets of requirements and specifications. This process has worked well in the past but fails to account for the strategic interdependence of design choices made prior to operating systems. However, as the world becomes increasingly competitive, and as the space domain becomes increasingly congested and contested, such interdependence of design can be described using Game Theory. Game Theory is the mathematical study of strategy, actions and payoffs between rational, self-interested actors. Limited extant research has applied Game Theory to system design but focused on a single system being designed cooperatively within a single …

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Model Based Systems Engineering Demonstrator For Air Worthiness With Performance Data Of Department Of Defense Rotorcraft, Bretton M. Bethel Mar 2021

Model Based Systems Engineering Demonstrator For Air Worthiness With Performance Data Of Department Of Defense Rotorcraft, Bretton M. Bethel

Theses and Dissertations

Airworthiness is a process of certifying that an aircraft can be safety operated within specified bounds. This process is essential to ensuring the safety of the aircraft, its personnel, and the surrounding assets. A Model-Based Systems Engineering (MBSE) approach can be utilized as a method to improve the airworthiness process. MBSE is the methodology of creating and utilizing domain models as a means of exchanging and presenting information for a wide variety of disciplines to understand and replacing previous document-based exchange. The objective of this research is to develop a reference architecture with a MBSE approach to perform the airworthiness …

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A Fuzzy Framework For The Air Force Mission Dependency Index, Devin M. Depalmer Mar 2021

A Fuzzy Framework For The Air Force Mission Dependency Index, Devin M. Depalmer

Theses and Dissertations

AFIMSC completed an MDI modernization to support better risk-based decision-making by utilizing tactical mission-owner knowledge to quantify the relationship between facilities and the missions they enable. The resulting facility-mission risk scores leave room for improvement for better use of their intended purposes due to (1) the vulnerability of cognitive biases affecting survey responses due to the use of a traditional risk matrix (2) the lack of resolution between scores from risk ties and (3) the failure to include information from the operational and strategic organizational hierarchy level. This research addresses these concerns through the novel implementation of a fuzzy logic …

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Optimizing Cost And Performance Of Infrastrucure Alternatives At Contingency Bases In A Hub-And-Spoke Network, Kyle J. Rodriguez Mar 2021

Optimizing Cost And Performance Of Infrastrucure Alternatives At Contingency Bases In A Hub-And-Spoke Network, Kyle J. Rodriguez

Theses and Dissertations

Military contingency bases require substantial resources and funding sustain and are often not connected to an infrastructure grid. Infrastructure assets produce the required outputs for sustainment, but are often expensive and inefficient, producing a significant logistical burden. With the increasing near-peer threats of opposing military forces, there is a need for more self-sufficient contingency bases with alternatives that reduce resources usage and the cost of sustainment. Accordingly, the goal of this research is to develop an optimization model capable of selecting infrastructure alternative combinations that minimize the overall resource usage and cost of sustainment at the contingency base level.

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Training Subject Matter Experts To Make Better Estimates, Cameron R. Scott Mar 2021

Training Subject Matter Experts To Make Better Estimates, Cameron R. Scott

Theses and Dissertations

Subject Matter Expert (SME) Elicitation is commonly used as a cost-estimation method when no historical data exists. The elicitation process assumes Subject Matter Experts are the resident experts in their individual fields of study. In addition, the process assumes SMEs provide reasonably trustworthy cost estimates that follow the tenets of probability theory. This last assumption is the subject of this study. A Navy sponsored e-learning course was created to help train SMEs in understanding probability distributions (O'Hagan, 2019). We conducted a study hypothesizing that taking the e-learning course would improve study participant accuracy in estimating confidence intervals for probability distributions.

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The Effect Of Molar Peroxide Ratio On The Oxidation Of 2,4-Dinitroanisole In An Ultraviolet Light Emitting Diode Advanced Oxidation Process, Troy M. Searcy Mar 2021

The Effect Of Molar Peroxide Ratio On The Oxidation Of 2,4-Dinitroanisole In An Ultraviolet Light Emitting Diode Advanced Oxidation Process, Troy M. Searcy

Theses and Dissertations

Insensitive munitions (IMs) are increasingly employed by the U.S. military to prevent unintended detonations associated with conventional munitions. One IM used extensively is 2,4 dinitroanisole (DNAN). This research employed an ultraviolet light emitting diode (LED) and hydrogen peroxide advanced oxidation process (AOP) to treat DNAN-contaminated water at the laboratory scale. Five molar peroxide ratios (50:1, 100:1, 250:1, 500:1, 1000:1) were evaluated using the observed pseudo first-order rate constant as the performance metric. Both peroxide-limiting reactions and radical scavenging were observed over the range of ratios tested, with overall removal of DNAN decreasing above a ratio of 500:1.

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Climate-Informed Prediction And Forecast Modeling Of Installation Total Energy Consumption, Scott C. Weiss Mar 2021

Climate-Informed Prediction And Forecast Modeling Of Installation Total Energy Consumption, Scott C. Weiss

Theses and Dissertations

Climate variability is an external and stochastic factor that causes energy demand uncertainty. Energy managers can use climate-based models to understand future trends of energy demand and to adjust operations, policy, and budgets accordingly. This research focuses on 1) identifying how climate attributes impact energy use, 2) creating a historically informed statistical modeling framework to skillfully predict energy use, and 3) forecasting future changes to energy use and costs, using CMIP5 temperature projections, at the campus level. After synthesizing the existing breadth of research on climate-informed energy modeling, a skillful, unbiased, climate-informed total energy consumption prediction model is developed for …

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Aircraft Inspection By Multirotor Uav Using Coverage Path Planning, Patrick H. Silberberg Mar 2021

Aircraft Inspection By Multirotor Uav Using Coverage Path Planning, Patrick H. Silberberg

Theses and Dissertations

All military and commercial aircraft must undergo frequent visual inspections in order to identify damage that could pose a danger to safety of flight. Currently, these inspections are primarily conducted by maintenance personnel. Inspectors must scrutinize the aircraft’s surface to find and document defects such as dents, hail damage, broken fasteners, etc.; this is a time consuming, tedious, and hazardous process. The goal of this work is to develop a visual inspection system which can be used by an Unmanned Aerial Vehicle (UAV), and to test the feasibility of this system on military aircraft. Using an autonomous system in place …

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Characterization And Analysis Of Bomarc Accident Debris, Aaron J. Heffelfinger Mar 2021

Characterization And Analysis Of Bomarc Accident Debris, Aaron J. Heffelfinger

Theses and Dissertations

Accidents involving nuclear weapons, such as the Boeing Michigan Aeronautical Research Center (BOMARC) accident in 1960, always pose a significant risk of allowing particles composed of nuclear materials to enter the environment. These particles often differ in characteristics and can be of greatly varying sizes. Gamma ray analysis was conducted on the soil sample and radioisotopes within the sample were identified. Two non-destructive methods for locating actinide bearing particles within the sample were testing, resulting in 70 actinide bearing particles ranging from 1-34 microns being identified. These 70 particles underwent both morphological and elemental characterization, indicating uranium and other elements.

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Contract Information Extraction Using Machine Learning, Zachary E. Butcher Mar 2021

Contract Information Extraction Using Machine Learning, Zachary E. Butcher

Theses and Dissertations

The Air Force Sustainment Center assisted by the Data Analytics Resource Team and the Defense Logistics Agency collected four million contracts onto one of the Air Force Research Laboratory’s high power computers. This thesis focuses on the effort to determine if parts are available through those contracts. Some information is extracted using machine learning in combination with natural language processing. Where machine learning methods are unsuccessful or inappropriate, text mining techniques, such as pattern recognition and rules, are used. Upon completion, the information is combined into a Gantt chart for quick evaluation. Only 21% of the contracts have their information …

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Error Reduction For The Determination Of Transverse Moduli Of Single-Strand Carbon Fibers Via Atomic Force Microscopy, Joshua D. Frey Mar 2021

Error Reduction For The Determination Of Transverse Moduli Of Single-Strand Carbon Fibers Via Atomic Force Microscopy, Joshua D. Frey

Theses and Dissertations

The transverse modulus of single strand carbon fibers is measured using PeakForce Atomic Force Microscopy - Quantitative Nanomechanical Measurement to less than 5 percent error for 11 types of carbon fiber with longitudinal moduli between 924-231 GPA, including export-controlled fibers. Statistical methods are employed to improve the quality of data to exclude outliers within an measurement and within the sample set. A positive linear correlation between the longitudinal and transverse modulus with an R2=0.76 is found. Pitch-based fibers exhibit lower measurement error than PAN-based fibers, while PAN fibers exhibited no apparent modulus correlation when the Pitch fibers are …

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Examining The Impact Of Logistics On Military Strength Among East Asian Nations Using Data Envelopment Analysis, Meaghan E. Crandell Mar 2021

Examining The Impact Of Logistics On Military Strength Among East Asian Nations Using Data Envelopment Analysis, Meaghan E. Crandell

Theses and Dissertations

The current narrative in logistics revolves around modernization and the rapid development and deployment of capabilities, which is a sentiment echoed across the Air Force and the DoD alike. However, the combination of intangible and tangible aspects of logistics can make it challenging to find a foundational place to start the process. The purpose of this study is to evaluate logistical factors to include land area, infrastructure, labor force, and GDP and their relationship to military power. This foundation will provide a baseline of areas for improvement and replication. Data Envelopment Analysis (DEA) and linear regression were leveraged to analyze …

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Enumerating And Locating Bluetooth Devices For Casualty Recovery In A First-Responder Environment, Justin M. Durham Mar 2021

Enumerating And Locating Bluetooth Devices For Casualty Recovery In A First-Responder Environment, Justin M. Durham

Theses and Dissertations

It is difficult for first-responders to quickly locate casualties in an emergency environment such as an explosion or natural disaster. In order to provide another tool to locate individuals, this research attempts to identify and estimate the location of devices that would likely be located on or with a person. A variety of devices, such as phones, smartwatches, and Bluetooth-enabled locks, are tested in multiple environments and at various heights to determine the impact that placement and interference played in locating the devices. The hypothesis is that most Bluetooth devices can be successfully enumerated quickly, but cannot be accurately located …

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Stochastic Programming Design For West Africa Logistics Networks, Julius C. Walker Mar 2021

Stochastic Programming Design For West Africa Logistics Networks, Julius C. Walker

Theses and Dissertations

The USAFRICOM is studying methods to increase the resiliency of its West African Logistic Network, a hub-and-spoke network design responsible for sustaining long term humanitarian and security missions in the West Africa region. This paper employs a two-stage stochastic programming network design modeled on the WALN that builds a flexible supply chain capable of responding to periodic disruptions while maintaining peak resiliency. Elements such as cost, probability, and event-based disruption are integrated into the model to mirror challenges the WALN faces. We demonstrate that incorporating resilient based response mechanism provide a 90% reduction in cost compared to meeting the logistical …

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