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Articles 961 - 990 of 5699
Full-Text Articles in Engineering
An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt, James E. Bevins, Stephen H. Baxter
An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt, James E. Bevins, Stephen H. Baxter
Faculty Publications
A 3-D Quarter-Core CANDU-6 is modeled using Serpent 2 for nuclear treaty monitoring. The spatial variation of flux spectra and isotopic concentrations is analyzed to determine the potential isotopic distribution of key radionuclides from standard reactor operations relevant to non-proliferation. The initial results of the model show a 46% difference in overall flux magnitude throughout the core as well as a 2-30% difference in discrete energy flux. The coupled production rate (magnitude) and spectral differences can contribute to significant spatial variations in isotope ratios throughout the core. Initial results indicate 239 Pu/ 240 Pu ratios vary by as much as …
Zynq System-On-Chip Dma Messaging For Processor Monitoring, Daniel F. Koranek, Douglas D. Hodson, Scott R. Graham
Zynq System-On-Chip Dma Messaging For Processor Monitoring, Daniel F. Koranek, Douglas D. Hodson, Scott R. Graham
Faculty Publications
Xilinx Zynq-7000 System-on-Chip architectures combine an ARM Cortex-A9 core with an FPGA fabric. One benefit of this hybrid architecture is that it allows fast prototyping of designs where the security of either the processing system (PS) is monitored by the programmable logic (PL) or vice versa. The choice of implementing a design in the PS or PL is driven by cost-to-benefit analysis across many factors. This effort examines the design process required to construct security monitoring designs that use both the PS and PL. For background, this effort reviews similar security monitoring projects. For the effort, a PL peripheral was …
Photoinduced Trapping Of Charge At Sulfur Vacancies And Copper Ions In Photorefractive Sn2P2S6 Crystals, Timothy D. Gustafson, Eric M. Golden, Elizabeth M. Scherrer, Nancy C. Giles, A. A. Grabar, Sergey A. Basun, Jonathan E. Slagle [*], Larry E. Halliburton
Photoinduced Trapping Of Charge At Sulfur Vacancies And Copper Ions In Photorefractive Sn2P2S6 Crystals, Timothy D. Gustafson, Eric M. Golden, Elizabeth M. Scherrer, Nancy C. Giles, A. A. Grabar, Sergey A. Basun, Jonathan E. Slagle [*], Larry E. Halliburton
Faculty Publications
Electron paramagnetic resonance (EPR) is used to monitor photoinduced changes in the charge states of sulfur vacancies and Cu ions in tin hypothiodiphosphate. A Sn2P2S6 crystal containing Cu+ (3d10) ions at Sn2+ sites was grown by the chemical vapor transport method. Doubly ionized sulfur vacancies (V2+S) are also present in the as-grown crystal (where they serve as charge compensators for the Cu+ ions). For temperatures below 70 K, exposure to 532 or 633 nm laser light produces stable Cu2+ (3d9) ions, as electrons move from Cu+ ions to …
Sparc: Statistical Performance Analysis With Relevance Conclusions, Justin C. Tullos, Scott R. Graham, Jeremy D. Jordan, Pranav R. Patel
Sparc: Statistical Performance Analysis With Relevance Conclusions, Justin C. Tullos, Scott R. Graham, Jeremy D. Jordan, Pranav R. Patel
Faculty Publications
The performance of one computer relative to another is traditionally characterized through benchmarking, a practice occasionally deficient in statistical rigor. The performance is often trivialized through simplified measures, such as the approach of central tendency, but doing so risks a loss of perspective of the variability and non-determinism of modern computer systems. Authentic performance evaluations are derived from statistical methods that accurately interpret and assess data. Methods that currently exist within performance comparison frameworks are limited in efficacy, statistical inference is either overtly simplified or altogether avoided. A prevalent criticism from computer performance literature suggests that the results from difference …
Development Of A Modular Mixed-Radiation Directional Rotating Scatter Mask Detection System, Bryan V. Egner, Darren E. Holland, Larry W. Burggraf, James E. Bevins
Development Of A Modular Mixed-Radiation Directional Rotating Scatter Mask Detection System, Bryan V. Egner, Darren E. Holland, Larry W. Burggraf, James E. Bevins
Faculty Publications
The ability to simultaneously identify the direction of both fast neutrons, above 1 MeV, and gamma rays using a light-weight system consisting of a single 1” EJ-309 organic liquid scintillator and a plastic Spartan rotating scatter mask (RSM) is demonstrated computationally through Monte Carlo simulations and validated with experimental measurements. Two sets of directional measurements were performed with an americium–beryllium source, emitting both neutrons and gamma rays. The RSM identified the direction of the source within one 10° rotational increment in the azimuthal and polar directions based on both the neutron and gamma-ray induced signals discriminated by charge integration pulse-shape …
On-Chip Silicon Photonic Controllable 2 × 2 Four-Mode Waveguide Switch, Cao Dung Truong, Duy Nguyen Thi Hang, Hengky Chandrahalim, Minh Tuan Trinh
On-Chip Silicon Photonic Controllable 2 × 2 Four-Mode Waveguide Switch, Cao Dung Truong, Duy Nguyen Thi Hang, Hengky Chandrahalim, Minh Tuan Trinh
Faculty Publications
Multimode optical switch is a key component of mode division multiplexing in modern high-speed optical signal processing. In this paper, we introduce for the first time a novel 2 × 2 multimode switch design and demonstrate in the proof-of-concept. The device composes of four Y-multijunctions and 2 × 2 multimode interference coupler using silicon-on-insulator material with four controllable phase shifters. The shifters operate using thermo-optic effects utilizing Ti heaters enabling simultaneous switching of the optical signal between the output ports on four quasi-transverse electric modes with the electric power consumption is in order of 22.5 mW and the switching time …
Agile Software Development: Creating A Cost Of Delay Framework For Air Force Software Factories, J. Goljan, Jonathan D. Ritschel, Scott Drylie, Edward D. White
Agile Software Development: Creating A Cost Of Delay Framework For Air Force Software Factories, J. Goljan, Jonathan D. Ritschel, Scott Drylie, Edward D. White
Faculty Publications
The Air Force software development environment is experiencing a paradigm shift. The 2019 Defense Innovation Board concluded that speed and cycle time must become the most important software metrics if the US military is to maintain its advantage over adversaries.1 This article proposes utilizing a cost-of-delay (CoD) framework to prioritize projects toward optimizing readiness. Cost-of-delay is defined as the economic impact resulting from a delaying product delivery or, said another way, opportunity cost. In principle, CoD assesses the negative impacts resulting from changes to the priority of a project.
Integrating Cost As A Decision Variable In Wargames, Joshua N. Reese, Jonathan D. Ritschel, Brent T. Langhals, Ryan D. Engle
Integrating Cost As A Decision Variable In Wargames, Joshua N. Reese, Jonathan D. Ritschel, Brent T. Langhals, Ryan D. Engle
Faculty Publications
The US military can no longer afford to be reactive, leaving critical cost analyses to the months and years following operations or full-scale conflicts. By leveraging cost in wargaming as part of the Joint planning process, DOD can provide Congress and the American taxpayers a range of potential costs associated with various military engagements that reflect fiscal and operational realities.
Understanding Flow Characteristics In Metal Additive Manufacturing, Carl R. Hartsfield, Travis E. Shelton, Gregory R. Cobb, Ryan A. Kemnitz, Joseph Weber
Understanding Flow Characteristics In Metal Additive Manufacturing, Carl R. Hartsfield, Travis E. Shelton, Gregory R. Cobb, Ryan A. Kemnitz, Joseph Weber
Faculty Publications
In fluid flow, the frictional effects from interior surfaces of flow components create pressure loss across the surface. Understanding this inherent pressure loss due to friction and other phenomena is important when designing a flow system. For conventional manufacturing, friction loss has been empirically studied and is well known in the engineering community. However, newer manufacturing techniques, such as laser powder bed fusion (LPBF), an additive manufacturing technique, need to be understood. The inherent flow conditions resulting from the additive processes were studied. Test samples were printed with the flow path oriented in the vertical direction with different channel diameters …
Resilience For Multi-Filter All-Source Navigation Framework With Integrity, Jonathon S. Gipson, Robert C. Leishman
Resilience For Multi-Filter All-Source Navigation Framework With Integrity, Jonathon S. Gipson, Robert C. Leishman
Faculty Publications
The Autonomous and Resilient Management of All-source Sensors (ARMAS) framework monitors residual-space test statistics across unique sensor-exclusion banks of filters, (known as subfilters) to provide a resilient, fault-resistant all-source navigation architecture with assurance. A critical assumption of this architecture, demonstrated in this paper, is fully overlapping state observability across all subfilters. All-source sensors, particularly those that only provide partial state information (altimeters, TDoA, AOB, etc.) do not intrinsically meet this requirement.
This paper presents a novel method to monitor real-time overlapping position state observability and introduces an "observability bank" within the ARMAS framework, known as Stable Observability Monitoring (SOM). SOM …
Quantifying The Effects Of Aircraft Engine Upgrades On Operating And Support Costs, Bradford A. Myers, Edward D. White, Jonathan D. Ritschel, R. David Fass
Quantifying The Effects Of Aircraft Engine Upgrades On Operating And Support Costs, Bradford A. Myers, Edward D. White, Jonathan D. Ritschel, R. David Fass
Faculty Publications
For fixed wing aircraft within the U.S. Air Force, Operating and Support (O&S) costs encompass a large portion of total life cycle costs. O&S costs include fuel, maintenance, and engine upgrades. To the authors’ knowledge, no study to date has attempted to empirically quantify the realized effects of new aircraft engines on sustainment costs. Utilizing the Air Force Total Ownership Cost database, they focused on new engines appearing on the C-5s, C-130s, and C-135s. Although narrow in scope, results suggest newer engines have lower fuel costs. Maintenance costs for newer engines were not consistently higher or lower than the engines …
Impact Of Neutron Energy On Asteroid Deflection Performance, Lansing S. Horan Iv, Darren E. Holland, Megan Bruck Syal, James E. Bevins, Joseph W. Wasem
Impact Of Neutron Energy On Asteroid Deflection Performance, Lansing S. Horan Iv, Darren E. Holland, Megan Bruck Syal, James E. Bevins, Joseph W. Wasem
Faculty Publications
In the future, a hazardous asteroid will find itself on a collision course with Earth. For asteroids of moderate size or larger, a nuclear device is one of humanity's only technologies capable of mitigating this threat via deflection on a timescale of less than a decade. This work examined how the output neutron energy from a nuclear device standoff detonation affects the deflection of a notional asteroid that is 300 meters in diameter and composed of silicon dioxide at a bulk density of 1.855 g/cm3. 14.1 MeV and 1 MeV neutron energy sources were modeled in MCNP to …
Comparing Greedy Constructive Heuristic Subtour Elimination Methods For The Traveling Salesman Problem, Petar Jackovich, Bruce A. Cox, Raymond R. Hill
Comparing Greedy Constructive Heuristic Subtour Elimination Methods For The Traveling Salesman Problem, Petar Jackovich, Bruce A. Cox, Raymond R. Hill
Faculty Publications
Purpose — This paper aims to define the class of fragment constructive heuristics used to compute feasible solutions for the traveling salesman problem (TSP) into edge-greedy and vertex-greedy subclasses. As these subclasses of heuristics can create subtours, two known methodologies for subtour elimination on symmetric instances are reviewed and are expanded to cover asymmetric problem instances. This paper introduces a third novel subtour elimination methodology, the greedy tracker (GT), and compares it to both known methodologies. Design/methodology/approach — Computational results for all three subtour elimination methodologies are generated across 17 symmetric instances ranging in size from 29 vertices to 5,934 …
Modified C-17 Taxi Procedures: A Fuel Cost Savings Exploration, Michael Wells, Michael Krester, Benjamin Hazen, Jeffery D. Weir
Modified C-17 Taxi Procedures: A Fuel Cost Savings Exploration, Michael Wells, Michael Krester, Benjamin Hazen, Jeffery D. Weir
Faculty Publications
Purpose — This study aims to explore the viability of using C-17 reduced-engine taxi procedures from a cost savings and capability perspective. Design/methodology/approach — This study model expected engine fuel flow based on the number of operational engines, aircraft gross weight (GW) and average aircraft groundspeed. Using this model, the research executes a cost savings simulation estimating the expected annual savings produced by the proposed taxi methodology. Operational and safety risks are also considered. Findings — The results indicate that significant fuel and costs savings are available via the employment of reduced-engine taxi procedures. On an annual basis, the mobility …
A Computational Investigation Of The Interstitial Oxidation Thermodynamics Of A Mo-Nb-Ta-W High Entropy Alloy Beyond The Dilute Regime, Adib J. Samin
A Computational Investigation Of The Interstitial Oxidation Thermodynamics Of A Mo-Nb-Ta-W High Entropy Alloy Beyond The Dilute Regime, Adib J. Samin
Faculty Publications
High entropy alloys (HEAs) are promising candidates for high-temperature structural material applications. Oxidation is a major factor that must be accounted for when designing such materials and it is thus important to study the oxidation behavior of HEAs to enable the optimum design of next generation materials. In this study, the thermodynamic behavior of interstitial oxygen in a Mo-Nb-Ta-W high entropy alloy was explored beyond the dilute limit. This was accomplished by sampling configurations of the HEA and HEA-oxygen systems from an isothermal–isobaric ensemble using a series of first-principle-based Monte Carlo simulations. It was found that the interstitial oxygen had …
Electro-Optic Satellite Constellation Design Using Multi-Objective Genetic Algorithm, Yasin Tamer
Electro-Optic Satellite Constellation Design Using Multi-Objective Genetic Algorithm, Yasin Tamer
Theses and Dissertations
Satellite constellation design is a complex, highly constrained, and multidisciplinary problem. Unless optimization tools are used, tradeoffs must be conducted at the subsystem level resulting in feasible, but not necessarily optimal, system designs. As satellite technology advances, new methods to optimize the system objectives are developed. This study is based on the development of a representative regional remote sensing constellation design. This thesis analyses the design process of an electrooptic satellite constellation with regional coverage considerations using system-level optimization tools. A multi objective genetic algorithm method is used to optimize the constellation design by utilizing MATLAB and STK integration. Cost, …
Continuous Integration/Continuous Delivery Pipeline For Air Force Distributed Common Ground System (Af Dcgs), Carolyn W. Fuller
Continuous Integration/Continuous Delivery Pipeline For Air Force Distributed Common Ground System (Af Dcgs), Carolyn W. Fuller
Theses and Dissertations
AF DCGS has a recognized need to improve speed of delivery for modification and sustainment of the weapon system. Given that the program office implemented a Continuous Integration/Continuous Delivery (CI/CD) process for the sole purpose of delivering capability to the field faster, there is a need to measure and report the pipeline throughput. This research conducts an independent evaluation of the newly implemented pipeline within AF DCGS’s existing integration and test laboratories. Actual project data from the agile development work environments is studied and hypothesis tests are conducted to substantiate that the CI/CD pipeline improved the speed of delivery. The …
Experimental And Computational Analysis Of Progressive Failure In Bolted Hybrid Composite Joints, John S. Brewer
Experimental And Computational Analysis Of Progressive Failure In Bolted Hybrid Composite Joints, John S. Brewer
Theses and Dissertations
Composite materials are strong, lightweight, and stiff making them desirable in aerospace applications. However, a practical issue arises with composites in that they behave unpredictably in bolted joints, where damage and cracks are often initiated. This research investigated a solution to correcting the problem with composite bolted joints. A novel hybrid composite material was developed, where thin stainless steel foils were placed between and in place of preimpregnated composite plies during the cure cycle to reinforce stress concentrations in bolted joints. This novel composite was compared to control samples experimentally in quasi-static monotonic loading in double shear configuration in 9-ply …
An Analysis Of The Benefits And Difficulties Of Aerial Magnetic Vector Navigation, Aaron J. Canciani, Christopher J. Brennan
An Analysis Of The Benefits And Difficulties Of Aerial Magnetic Vector Navigation, Aaron J. Canciani, Christopher J. Brennan
Faculty Publications
Recent successful flight tests have demonstrated scalar magnetic anomaly navigation to be a viable GPS-alternative navigation system. These flight tests matched magnetic field measurements to maps of the Earth's crustal magnetic field in order to navigate. Scalar magnetic navigation uses only the magnetic field intensity, not direction, in order to navigate. While it appears obvious to extend aerial magnetic navigation to use the full vector field, in practice there are substantial obstacles to doing so. This article explores the key challenges of magnetic vector navigation including current sensor limitations, lack of high frequency magnetic vector maps of the Earth's crust, …
The Effects Of Aircraft Use And Available Repar Spares On Aircraft Sortie Generaiton: A Long-Duration Logistical Wargaming Simulationtool, Nathaniel M. Choo
The Effects Of Aircraft Use And Available Repar Spares On Aircraft Sortie Generaiton: A Long-Duration Logistical Wargaming Simulationtool, Nathaniel M. Choo
Theses and Dissertations
A long-duration logistical wargame simulation tool that can provide quick insights into the daily aircraft availability and the daily number of missions accomplished for a variety of operational scenarios is developed. This simulation tool is designed to be a stepwise wargaming support tool for adjudication within long-duration logistical wargames and provides the user many capabilities including, but not limited to, the ability to have multiple bases and types of aircraft. Additionally, the user has the ability to control types of part failures, control parts availability, control maintenance capabilities, and control number of mission scheduled. Finally, the user can account for …
Assessing Observer Stations For Cislunar Space Domain Awareness, Michael S. Rosenof
Assessing Observer Stations For Cislunar Space Domain Awareness, Michael S. Rosenof
Theses and Dissertations
With renewed worldwide interest in cislunar space, the need for reliable domain awareness in that extended region of space is clear. This investigation quantifies the suitability of several possible stations for observer satellites in cislunar space by calculating the specific irradiance each would observe as they track satellites in various realistic lunar free-return trajectories across a decade, using reflected sunlight. This investigation includes one class of free return trajectories for target satellites, eleven distinct observer stations, and three different metrics for comparing the effectiveness of each observer station or combination of observer stations for sensing targets using reflected sunlight. The …
Sparse Bases And Bayesian Inference Of Electromagnetic Scattering, John Lee
Sparse Bases And Bayesian Inference Of Electromagnetic Scattering, John Lee
Theses and Dissertations
Many approaches in CEM rely on the decomposition of complex radiation and scattering behavior with a set of basis vectors. Accurate estimation of the quantities of interest can be synthesized through a weighted sum of these vectors. In addition to basis decompositions, sparse signal processing techniques developed in the CS community can be leveraged when only a small subset of the basis vectors are required to sufficiently represent the quantity of interest. We investigate several concepts in which novel bases are applied to common electromagnetic problems and leverage the sparsity property to improve performance and/or reduce computational burden. The first …
Electromagnetic Interference Estimation Via Conditional Neural Processing, Edgar E. Gomez
Electromagnetic Interference Estimation Via Conditional Neural Processing, Edgar E. Gomez
Theses and Dissertations
The goal of this thesis is to determine the efficacy of employing Machine Learning (ML) to solve Joint Urgent Operational Need (JUON) CC-0575, which aims to develop a Common Operating Picture (COP) of the Global Positioning System (GPS) Electromagnetic Interference (EMI) environment. With the growing popularity of Artificial Neural Networks (ANNs), ML solutions are quickly gaining traction in businesses, academia and government. This in turn allows for problem solutions that were previously inconceivable using the classical programming paradigm. This thesis proposes a method to develop a COP of the battlefield via ANN ingestion of multiple-source signals and sensors. We conduct …
Deep Learning-Based, Passive Fault Tolerant Control Facilitated By A Taxonomy Of Cyber-Attack Effects, Dean C. Wardell
Deep Learning-Based, Passive Fault Tolerant Control Facilitated By A Taxonomy Of Cyber-Attack Effects, Dean C. Wardell
Theses and Dissertations
In the interest of improving the resilience of cyber-physical control systems to better operate in the presence of various cyber-attacks and/or faults, this dissertation presents a novel controller design based on deep-learning networks. This research lays out a controller design that does not rely on fault or cyber-attack detection. Being passive, the controller’s routine operating process is to take in data from the various components of the physical system, holistically assess the state of the physical system using deep-learning networks and decide the subsequent round of commands from the controller. This use of deep-learning methods in passive fault tolerant control …
Analysis For Hybrid Rocket Fuel Regression Using Stereolithographic Geometry, Michael P. King
Analysis For Hybrid Rocket Fuel Regression Using Stereolithographic Geometry, Michael P. King
Theses and Dissertations
Hybrid Rocket Engines (HRE) have characteristically low fuel regression that limits their performance. Additive manufacturing and rapid prototyping can possibly solve some of the problems with Hybrid propulsion regression by creating geometry not possible with conventional manufacturing. This work is attempting to make geometric regression simulation of HRE easier by using STereoLithography (STL files) as the geometry. This analysis sets flow conditions, boundary conditions, propellant selection, and allows for fuel geometry to be altered to simulate geometry’s effects on regression rate and propellant performance. This model can be used for more advanced geometric analysis to improve and predict performance.
Homotopy Simulation Of Dissipative Micropolar Flow And Heat Transfer From A Two-Dimensional Body With Heat Sink Effect: Applications In Polymer Coating, O. A. Bég, B. Vasu, A. K. Ray, T. A. Beg, A. Kadir, H. J. Leonard, Rama S. R. Gorla
Homotopy Simulation Of Dissipative Micropolar Flow And Heat Transfer From A Two-Dimensional Body With Heat Sink Effect: Applications In Polymer Coating, O. A. Bég, B. Vasu, A. K. Ray, T. A. Beg, A. Kadir, H. J. Leonard, Rama S. R. Gorla
Faculty Publications
Non-Newtonian flow from a wedge constitutes a fundamental problem in chemical engineering systems and is relevant to processing of polymers, coating systems, etc. Motivated by such applications, the homotopy analysis method (HAM) was employed to obtain semi-analytical solutions for thermal convection boundary layer flow of incompressible micropolar fluid from a two-dimensional body (wedge). Viscous dissipation and heat sink effects were included. The non-dimensional boundary value problem emerges as a system of nonlinear coupled ordinary differential equations, by virtue of suitable coordinate transformations. The so-called Falkner-Skan flow cases are elaborated. Validation of the HAM solutions was achieved with earlier simpler models, …
Specifying Space Defense Operator Interfaces Through The Application Of Cognitive Systems Engineering And Prototyping, Justin E. Oryschak
Specifying Space Defense Operator Interfaces Through The Application Of Cognitive Systems Engineering And Prototyping, Justin E. Oryschak
Theses and Dissertations
The Department of Defense needs better tools to support its operators as they strive to defend its space assets. The growing sophistication of anti-satellite weapons increasingly challenges the nation’s orbital communications and surveillance infrastructure. Operators face difficulties gathering useful information and dealing with the complexity of potential enemy actions. This research applied cognitive systems engineering and ecological interface design (EID) methodologies to create a prototype space mission management tool that enhances operator situation awareness and decision-making ability. Applied cognitive task analysis interviews were used to document space operator decision-making in their domain. Model-based systems engineering was applied to integrate work …
Hexakis Icosahedron Frame-Skin Vacuum Lighter Than Air Vehicle, Brian Cranston, Anthony N. Palazotto
Hexakis Icosahedron Frame-Skin Vacuum Lighter Than Air Vehicle, Brian Cranston, Anthony N. Palazotto
AFIT Patents
A vacuum lighter than air vehicle (VLTAV) includes a rigid frame of rods connected together to form a hexakis icosahedron. A membrane skin covers the rigid frame and defines therewith a vessel configured to hold an internal vacuum that allows the vessel to float in the air. The plurality of rods and membrane skin have weights and dimensions that result in a neutral and/or positive buoyancy for the vessel while preventing geometric instability.
Temporally Multiplexed Ladar Polarimeter, Christian Keyser, Richard Kenneth Martin
Temporally Multiplexed Ladar Polarimeter, Christian Keyser, Richard Kenneth Martin
AFIT Patents
In a polarimeter, a polarization modulator changes a polarization phase of an output optical pulse with a modulation function that varies in time over the duration of the optical pulse. A static polarization state analyzer, which includes a one or more static polarization component analyzers and detectors, receives the modulated optical pulse after interaction with a target medium and provides time varying intensities of the polarization components of the received pulse. A signal processing module determines a polarization property of the target medium, such as a Mueller matrix, dependent upon time varied intensities over the duration of the received optical …
Cost Estimating Using A New Learning Curve Theory For Non-Constant Production Rates, Dakotah Hogan, John J. Elshaw, Clay M. Koschnick, Jonathan D. Ritschel, Adedeji B. Badiru, Shawn M. Valentine
Cost Estimating Using A New Learning Curve Theory For Non-Constant Production Rates, Dakotah Hogan, John J. Elshaw, Clay M. Koschnick, Jonathan D. Ritschel, Adedeji B. Badiru, Shawn M. Valentine
Faculty Publications
Traditional learning curve theory assumes a constant learning rate regardless of the number of units produced. However, a collection of theoretical and empirical evidence indicates that learning rates decrease as more units are produced in some cases. These diminishing learning rates cause traditional learning curves to underestimate required resources, potentially resulting in cost overruns. A diminishing learning rate model, namely Boone’s learning curve, was recently developed to model this phenomenon. This research confirms that Boone’s learning curve systematically reduced error in modeling observed learning curves using production data from 169 Department of Defense end-items. However, high amounts of variability in …