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Articles 1 - 30 of 2659
Full-Text Articles in Engineering
Real-Time Synthesis Of A Nonuniformly Correlated, Partially Coherent Beam Using An Optical Coordinate Tansformation, Milo W. Hyde Iv
Real-Time Synthesis Of A Nonuniformly Correlated, Partially Coherent Beam Using An Optical Coordinate Tansformation, Milo W. Hyde Iv
Faculty Publications
We design, build, and validate an optical system for generating light beams with complex spatial coherence properties in real time. Beams of this type self-focus and are resistant to turbulence degradation, making them potentially useful in applications such as optical communications. We begin with a general theoretical analysis of our proposed design. Our approach starts by generating a Schell-model (uniformly correlated or shift-invariant) source by spatially filtering incoherent light. We then pass this light through an optical coordinate transformer, which converts the Schell-model source into a nonuniformly correlated field. After the general analysis, we discuss system engineering, including trade-offs among …
Production Box Cost Estimating Relationships For Dod Avionics, Carla J. Cisneros, Edward D. White, Brandon M. Lucas, Jonathan D. Ritschel, Robert D. Fass, Shawn M. Valentine
Production Box Cost Estimating Relationships For Dod Avionics, Carla J. Cisneros, Edward D. White, Brandon M. Lucas, Jonathan D. Ritschel, Robert D. Fass, Shawn M. Valentine
Faculty Publications
The authors use historical information obtained from the Cost Assessment Data Enterprise to estimate recurring production unit cost for DoD avionics via cost estimating relationships (CERs). The specific modeled responses include mean unit cost, median unit cost, and the 100th production unit cost (T100) utilizing learning curve theory. For T100, the authors adopt both a multiplicative and an additive error for CER comparison. Recommended CERs consist of the mean unit cost and the T100 utilizing a multiplicative error. Moreover, results reveal that weight has a significant effect on cost as well as a potential underaccounting of real price change or …
High-Fidelity Machine Learning Techniques For Driver Drowsiness Detection, Yasser Ismail, Ebenezer Essel, Abeer Abdelhamid, Mahmoud Darwich, Fahmi Khalifa, Fred Lacy
High-Fidelity Machine Learning Techniques For Driver Drowsiness Detection, Yasser Ismail, Ebenezer Essel, Abeer Abdelhamid, Mahmoud Darwich, Fahmi Khalifa, Fred Lacy
Faculty Publications
It is devastating that daily, there is an ample number of car crashes that cause damage to automobiles, onboard passengers get injured, and others tend to lose their lives. Road crashes are fast rising across the globe and have drawn many road safety commissions and concerned individuals to discuss ways to reduce this menacing situation drastically. With the introduction of artificial intelligence and technological advancement, the government and state commissions have beckoned on the various universities and research institutions to develop methods to curb the rise of automobile crashes. Some causes of these crashes include drunk driving and drowsiness, the …
A Panel Data Regression Model For Defense Merger And Acquisition Activity, Corey D. Mack, Clay Koschnick, Michael Brown, Jonathan D. Ritschel, Brandon M. Lucas
A Panel Data Regression Model For Defense Merger And Acquisition Activity, Corey D. Mack, Clay Koschnick, Michael Brown, Jonathan D. Ritschel, Brandon M. Lucas
Faculty Publications
Excerpt: This paper examines the relationship between a prime contractor's financial health and its mergers and acquisitions (M&A) spending in the defense industry. It aims to provide models that give the United States Department of Defense (DoD) indications of future M&A activity, informing decision-makers and contributing to ensuring competitive markets that benefit the consumer.
The results show a significant relationship between efficiency and M&A spending, indicating that companies with lower efficiency tend to spend more on M&As. However, there was no significant relationship between M&A spending and a company's profitability or solvency. These results were consistent with previous research and …
Enhancing Crossflow Dynamics Through The Gas Injection From Multiple Cylinders, Sahrish B. Naqvi, Sadia Siddiqa, Maciej Matyka, Rama S. R. Gorla, Md. Mamum Molla
Enhancing Crossflow Dynamics Through The Gas Injection From Multiple Cylinders, Sahrish B. Naqvi, Sadia Siddiqa, Maciej Matyka, Rama S. R. Gorla, Md. Mamum Molla
Faculty Publications
We investigate unsteady, two-dimensional laminar fluid flow around cylinders, focusing on understanding the impact of injecting methane gas through two diametrically opposite arcs on the cylinder in the crossflow of the second fluid. This study encompasses applications in mixing and dispersion, which are crucial in various technological and natural processes. Our analysis addresses velocity field’s contribution to the spatiotemporal distribution of transported quantities. We observed that mixing induces a transition from laminar to turbulent flow. Depending on the injected-to-crossflow velocity ratios, the wake vortices downstream of cylinder arrays separate from or connect to the injected gas. This phenomenon significantly impacts …
Comparing Gas Composition From Fast Pyrolysis Of Live Foliage Measured In Bench-Scale And Fire-Scale Experiments, David R. Weise, Thomas H. Fletcher, Timothy J. Johnson, Wei Min Hao, Mark Dietenberger, Marko Princevac, Bret W. Butler, Sara S. Mcallister, Joseph J. O'Brien, E Louise Loudermilk, Roger D. Ottmar, Andrew T. Hudak, Akira Kato, Babak Shotorban, Shankar Mahalingham, Tanya L. Myers, Javier Palarea-Albaladejo, Stephen P. Baker
Comparing Gas Composition From Fast Pyrolysis Of Live Foliage Measured In Bench-Scale And Fire-Scale Experiments, David R. Weise, Thomas H. Fletcher, Timothy J. Johnson, Wei Min Hao, Mark Dietenberger, Marko Princevac, Bret W. Butler, Sara S. Mcallister, Joseph J. O'Brien, E Louise Loudermilk, Roger D. Ottmar, Andrew T. Hudak, Akira Kato, Babak Shotorban, Shankar Mahalingham, Tanya L. Myers, Javier Palarea-Albaladejo, Stephen P. Baker
Faculty Publications
Background. Fire models have used pyrolysis data from oxidising and non-oxidising environments for flaming combustion. In wildland fires pyrolysis, flaming and smouldering combustion typically occur in an oxidising environment (the atmosphere). Aims. Using compositional data analysis methods, determine if the composition of pyrolysis gases measured in non-oxidising and ambient (oxidising) atmospheric conditions were similar. Methods. Permanent gases and tars were measured in a fuel-rich (non-oxidising) environment in a flat flame burner (FFB). Permanent and light hydrocarbon gases were measured for the same fuels heated by a fire flame in ambient atmospheric conditions (oxidising environment). Log-ratio balances of the measured gases …
Magnetic Sensor Compensation Utilizing Factor Graph Estimation, Frederic W. Lathrop, Clark N. Taylor, Aaron Nielsen
Magnetic Sensor Compensation Utilizing Factor Graph Estimation, Frederic W. Lathrop, Clark N. Taylor, Aaron Nielsen
Faculty Publications
Recently, there has been significant interest in the ability to navigate without GPS using the magnetic anomaly field of the Earth (magnav). One of the key technical bottlenecks to achieving magnav is obtaining an accurate magnetic sensor calibration, taking into account own-ship and sensor effects. The Tolles-Lawson magnetic calibration method continues to be the industry standard and was developed when airborne magnetic survey aircraft were first employed over 70 years ago. In this paper, we present a magnetic calibration algorithm based on a factor graph optimization using inertial measurements as well as inputs from both a vector and scalar magnetometer. …
Tension–Compression Fatigue Of A Hybrid Polymer-Matrix/Ceramic-Matrix Composite At Elevated Temperature, Marina B. Ruggles-Wrenn, Joshua Schmidt
Tension–Compression Fatigue Of A Hybrid Polymer-Matrix/Ceramic-Matrix Composite At Elevated Temperature, Marina B. Ruggles-Wrenn, Joshua Schmidt
Faculty Publications
Fully reversed tension–compression fatigue of a hybrid material comprising polymer matrix composite (PMC) co-cured with a ceramic matrix composite (CMC) was investigated. The PMC portion had a polyimide matrix reinforced with 15 plies of carbon fibers woven in an eight-harness satin weave (8HSW). The CMC portion had three plies of a quartz-fiber 8HSW fabric in a zirconia-based ceramic matrix. The hybrid PMC/CMC was developed for use in aerospace thermal protection systems (TPS). Hence, the experimental setup aimed to simulate the TPS service environment—the CMC side was kept at 329 °C, whereas the PMC side was open to laboratory air. Compression …
Geometrically Exact Beam Theory For Gradient-Based Optimization, Taylor Mcdonnell, Andrew Ning
Geometrically Exact Beam Theory For Gradient-Based Optimization, Taylor Mcdonnell, Andrew Ning
Faculty Publications
Decades of research have progressed geometrically exact beam theory to the point where it is now an invaluable resource for analyzing and modeling highly flexible slender structures. Large-scale optimization using geometrically exact beam theory remains nontrivial, however, due to the inability of gradient-free optimizers to handle large numbers of design variables in a computationally efficient manner and the difficulties associated with obtaining smooth, accurate, and efficiently calculated design sensitivities for gradient-based optimization. To overcome these challenges, this paper presents a finite-element implementation of geometrically exact beam theory which has been developed specifically for gradient-based optimization. A key feature of this …
An Integrated Space Test Lexicon: A Taxonomy For The Integrated Test And Evaluation Of Space Systems, Stephen Tullino, Andrew Keys, Robert A. Bettinger, Amy M. Cox, David R. Jacques
An Integrated Space Test Lexicon: A Taxonomy For The Integrated Test And Evaluation Of Space Systems, Stephen Tullino, Andrew Keys, Robert A. Bettinger, Amy M. Cox, David R. Jacques
Faculty Publications
The proposed Integrated Space Test Lexicon is intended to amalgamate the numerous definitions of integrated (IT or IT&E), development test (DT or DT&E), and operational test (OT or OT&E) into unified, service-wide definitions, aligned with the Space Test Enterprise Vision. Refining such definitions will help distill the core characteristics of these fundamental test types to first identify space system activities composing what is traditionally known as DT and OT, then to provide a means of how these activities fit into the IT paradigm and support space system development. In forging a common understanding of how DT and OT support space …
Derivative Propagation Through Vortex Particle Method Simulation, Eric Green, Andrew Ning
Derivative Propagation Through Vortex Particle Method Simulation, Eric Green, Andrew Ning
Faculty Publications
Automatic differentiation (AD) is a powerful tool for evaluating numerical derivatives. In particular, reverse-mode AD provides numerical gradients in a way that is insensitive to the number of input variables. This makes reverse-mode AD well-suited for solving large optimization problems. However, reverse-mode AD has a particularly large associated memory cost because most intermediate values in operations need to be cached. This is problematic for large problems such as aerodynamics simulations, though, since the memory requirements can quickly become impractical. The solution implemented in this work is to provide analytic pullback expressions for functions for which many of the intermediate values …
Trajectory Optimization Of Evtol And Conventional Aircraft: A Comparative Analysis Of Vortex Particle Method And Vortex Lattice + Blade Element Momentum Theory, Andrew Tagg, Ryan Anderson, Cibin Joseph, Andrew Ning
Trajectory Optimization Of Evtol And Conventional Aircraft: A Comparative Analysis Of Vortex Particle Method And Vortex Lattice + Blade Element Momentum Theory, Andrew Tagg, Ryan Anderson, Cibin Joseph, Andrew Ning
Faculty Publications
Trajectory optimization of aircraft transition maneuvers can significantly influence the design of these systems, particularly when making decisions about aircraft geometry, propulsion sizing, and control system design. This paper presents the trajectory optimization of air vehicles including electric vertical takeoff and landing (eVTOL) as well as conventional aircraft. The study evaluates the influence of fidelity in trajectory design by comparing the use of two aerodynamic methods in the context of trajectory optimization. The mid-fidelity method utilizes a vortex lattice method (VLM) to model lifting surfaces while employing blade element momentum theory (BEMT) to model rudimentary rotor-wing interactions. The high-fidelity approach …
Solving Unsteady Potential Flow Problems In O(N) Time, Ryan Anderson, Andrew Ning
Solving Unsteady Potential Flow Problems In O(N) Time, Ryan Anderson, Andrew Ning
Faculty Publications
Design of vertical takeoff and landing aircraft is challenging in part due to significant aerodynamic interactions between rotors and wings. Computational models can aid in their design, but are computationally expensive. 3-D panel methods coupled with vortex particle wakes offer an attractive solution, but solving for the panel strengths scales poorly for large problems. Multigrid methods, such as Krylov subspace methods in conjunction with the fast multipole method (FMM), have been demonstrated to reduce the scaling to O(𝑁). We explore the performance and limitations of the Krylov-FMM method, traditional matrix-powered GMRES, LU decomposition, and a novel O(𝑁) multigrid approach to …
Characteristics Of Pyrolysis Products Of California Chaparral And Their Potential Effect On Wildland Fires, Mahsa Alizadeh, David R. Weise, Thomas H. Fletcher
Characteristics Of Pyrolysis Products Of California Chaparral And Their Potential Effect On Wildland Fires, Mahsa Alizadeh, David R. Weise, Thomas H. Fletcher
Faculty Publications
The aim of this study was to investigate the pyrolysis of selected California foliage and estimate the energy content of the released volatiles to show the significance of the pyrolysis of foliage and its role during wildland fires. While the majority of the volatiles released during the pyrolysis of foliage later combust and promote fire propagation, studies on the energy released from combustion of these compounds are scarce. Samples of chamise (Adenostoma fasciculatum), Eastwood’s manzanita (Arctostaphylos glandulosa), scrub oak (Quercus berberidifolia), hoaryleaf ceanothus (Ceanothus crassifolius), all native to southern California, and sparkleberry …
Ductape: A Steady-State, Axisymmetric Ducted Fan Analysis Code Designed For Gradient-Based Optimization, Judd Mehr, Andrew Ning
Ductape: A Steady-State, Axisymmetric Ducted Fan Analysis Code Designed For Gradient-Based Optimization, Judd Mehr, Andrew Ning
Faculty Publications
Electric ducted fans have become an intriguing option for the propulsion systems of clean, quiet advanced air mobility technologies due to their potential benefits in both aerodynamic efficiency and reduced noise profiles compared to open rotor systems. Exploration of conceptual electric ducted fan design in the context of novel, and often complex, applications may be greatly aided by the use of optimization techniques. Specifically, gradient-based optimization lends itself to the exploration of large, complex, multi-disciplinary systems due to its inherent scalability. Despite ducted fans/propellers having been relatively well studied for the last century, modern, gradient-based, optimization-ready analysis tools for ducted …
Probabilistic Estimation Of Cadence And Walking Speed From Floor Vibrations, Yohanna Mejiacruz, Juan M. Caicedo, Zhaoshuo Jiang, Jean M. Franco
Probabilistic Estimation Of Cadence And Walking Speed From Floor Vibrations, Yohanna Mejiacruz, Juan M. Caicedo, Zhaoshuo Jiang, Jean M. Franco
Faculty Publications
Objective: This research aims to extract human gait parameters from floor vibrations. The proposed approach provides an innovative methodology on occupant activity, contributing to a broader understanding of how human movements interact within their built environment. Methods and Procedures: A multilevel probabilistic model was developed to estimate cadence and walking speed through the analysis of floor vibrations induced by walking. The model addresses challenges related to missing or incomplete information in the floor acceleration signals. Following the Bayesian Analysis Reporting Guidelines (BARG) for reproducibility, the model was evaluated through twenty-seven walking experiments, capturing floor vibration and data from Ambulatory Parkinson’s …
A First Step Towards Understanding Thermomechanical Behavior Of The Nb-Cr System Through Interatomic Potential Development And Molecular Dynamics Simulations, Lucas A. Heaton, Adib J. Samin
A First Step Towards Understanding Thermomechanical Behavior Of The Nb-Cr System Through Interatomic Potential Development And Molecular Dynamics Simulations, Lucas A. Heaton, Adib J. Samin
Faculty Publications
Utilizing a preliminary interatomic potential, this work represents an initial exploration into the thermomechanical behavior of NbCr solid solutions. Specifically, it examines the effect of different amounts of Cr solute, for which information in the literature is limited. The employed interatomic potential was developed according to the embedded atom model (EAM), and was trained on data derived from density functional theory calculations. While the potential demonstrated reasonable accuracy and predictive power when tested, various results highlight deficiencies and encourage further development and training. Mechanical strength, heat capacities, thermal expansion coefficients, and thermal conductivities were found to decrease with Cr content. …
Quantifying Variation Across 16s Rrna Gene Sequencing Runs In Human Microbiome Studies, Andrew J. Hoisington, Christopher E. Stamper, Joseph C. Ellis, Christopher A. Lowry, Lisa A. Brenner
Quantifying Variation Across 16s Rrna Gene Sequencing Runs In Human Microbiome Studies, Andrew J. Hoisington, Christopher E. Stamper, Joseph C. Ellis, Christopher A. Lowry, Lisa A. Brenner
Faculty Publications
Recent microbiome research has incorporated a higher number of samples through more participants in a study, longitudinal studies, and metanalysis between studies. Physical limitations in a sequencing machine can result in samples spread across sequencing runs. Here we present the results of sequencing nearly 1000 16S rRNA gene sequences in fecal (stabilized and swab) and oral (swab) samples from multiple human microbiome studies and positive controls that were conducted with identical standard operating procedures. Sequencing was performed in the same center across 18 different runs. The simplified mock community showed limitations in accuracy, while precision (e.g., technical variation) was robust …
Business Process Anomaly Detection And Root Cause Analysis Using Blstm-Vae With Attention, Yasser Ismail, Eman El-Aziz, Radwa Fathalla, Mohamed Shaheen
Business Process Anomaly Detection And Root Cause Analysis Using Blstm-Vae With Attention, Yasser Ismail, Eman El-Aziz, Radwa Fathalla, Mohamed Shaheen
Faculty Publications
Detecting anomalous executions in business process data is crucial for safeguarding the efficiency and success of an organization. Unsupervised approaches are commonly used for business process anomaly detection because of the scarcity of labeled anomaly data. However, these approaches often encounter a notable decline in performance because they lack prior knowledge about the anomalies. Additionally, most of them do not perform root cause analysis on the detected anomalies. This study proposes a variational autoencoder-based approach to overcome the performance limitations of existing unsupervised methods and determine the root causes of the detected anomalies. The learning of the variational autoencoder from …
Effects Of Rf Signal Eventization Encoding On Device Classification Performance, Michael J. Smith, Michael A. Temple, James W. Dean
Effects Of Rf Signal Eventization Encoding On Device Classification Performance, Michael J. Smith, Michael A. Temple, James W. Dean
Faculty Publications
The results of first-step research activity are presented for realizing an envisioned “event radio” capability that mimics neuromorphic event-based camera processing. The energy efficiency of neuromorphic processing is orders of magnitude higher than traditional von Neumann-based processing and is realized through synergistic design of brain-inspired software and hardware computing elements. Relative to event-based cameras, the development of event-based hardware devices supporting Radio Frequency (RF) applications is severely lagging and considerable interest remains in obtaining neuromorphic efficiency through event-based RF signal processing. In the Operational Technology (OT) protection arena, this includes efficient software computing capability to provide reliable device classification. A …
Analysis Of Modeled 3d Solar Magnetic Field During 30 X/M-Class Solar Flares, Seth H. Garland, Vasyl B. Yurchyshyn, Robert D. Loper, Benjamin F. Akers
Analysis Of Modeled 3d Solar Magnetic Field During 30 X/M-Class Solar Flares, Seth H. Garland, Vasyl B. Yurchyshyn, Robert D. Loper, Benjamin F. Akers
Faculty Publications
Using non-linear force free field (NLFFF) extrapolation, 3D magnetic fields were modeled from the 12-min cadence Solar Dynamics Observatory Helioseismic and Magnetic Imager (HMI) photospheric vector magnetograms, spanning a time period of 1 hour before through 1 hour after the start of 18 X-class and 12 M-class solar flares. Several magnetic field parameters were calculated from the modeled fields directly, as well as from the power spectrum of surface maps generated by summing the fields along the vertical axis, for two different regions: areas with photospheric |Bz|≥ 300 G (active region—AR) and areas above the photosphere with the …
Deep Selenium Donors In Zngep2 Crystals: An Electron Paramagnetic Resonance Study Of A Nonlinear Optical Material, Timothy D. Gustafson, Larry E. Halliburton, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, J. Jesenovec, Kent L. Averett, Jonathan E. Slagle [*]
Deep Selenium Donors In Zngep2 Crystals: An Electron Paramagnetic Resonance Study Of A Nonlinear Optical Material, Timothy D. Gustafson, Larry E. Halliburton, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, J. Jesenovec, Kent L. Averett, Jonathan E. Slagle [*]
Faculty Publications
Zinc germanium diphosphide (ZnGeP2) is a ternary semiconductor best known for its nonlinear optical properties. A primary application is optical parametric oscillators operating in the mid-infrared region. Controlled donor doping provides a method to minimize the acceptor-related absorption bands that limit the output power of these devices. In the present study, a ZnGeP2 crystal is doped with selenium during growth. Selenium substitutes for phosphorus and serves as a deep donor. Significant concentrations of native defects (zinc vacancies, germanium-on-zinc antisites, and phosphorous vacancies) are also present in the crystal. Electron paramagnetic resonance (EPR) is used to establish the …
Effect Of Fabrication Parameters On The Ferroelectricity Of Hafnium Zirconium Oxide Films: A Statistical Study, Guillermo A. Salcedo, Ahmad E. Islam, Elizabeth Reichley, Michael Dietz, Christine M. Schubert Kabban, Kevin D. Leedy, Tyson C. Back, Weison Wang, Andrew Green, Timothy S. Wolfe, James M. Sattler
Effect Of Fabrication Parameters On The Ferroelectricity Of Hafnium Zirconium Oxide Films: A Statistical Study, Guillermo A. Salcedo, Ahmad E. Islam, Elizabeth Reichley, Michael Dietz, Christine M. Schubert Kabban, Kevin D. Leedy, Tyson C. Back, Weison Wang, Andrew Green, Timothy S. Wolfe, James M. Sattler
Faculty Publications
Ferroelectricity in hafnium zirconium oxide (Hf1−xZrxO2) and the factors that impact it have been a popular research topic since its discovery in 2011. Although the general trends are known, the interactions between fabrication parameters and their effect on the ferroelectricity of Hf1−xZrxO2 require further investigation. In this paper, we present a statistical study and a model that relates Zr concentration (x), film thickness (tf), and annealing temperature (Ta) with the remanent polarization (Pr) in tungsten (W)-capped Hf1−xZrxO2. …
Technical Data Package For Sysmlv2 Vignettes, Allen W. Dukes
Technical Data Package For Sysmlv2 Vignettes, Allen W. Dukes
Faculty Publications
This Technical Data Package (TDP) thoroughly compiles instructions, concepts, and solutions for eight SysMLv2 vignettes. Each vignette illustrates methods to solve complex system modeling challenges. The initial concept for each vignette can drive the use and evaluation of a custom SysMLv2 modeling tool as shown in [1]. They can support a baseline set of tasks to compare usability with other SysMLv2 modeling software tools.
The document starts with three pairs of vignettes for modeling a hypothetical Unmanned Aerial Vehicle (UAV) operated with a Virtual Reality (VR) headset derived from AFIT WKSP 696. The final pair of vignettes focus on two …
Laboratory Exercise For The Radiometry Student, Michael A. Marciniak
Laboratory Exercise For The Radiometry Student, Michael A. Marciniak
Faculty Publications
The U.S. Air and Space Forces require optical expertise among their personnel. The Air Force Institute of Technology offers a graduate optics curriculum, which includes a three-course sequence to educate students in the optical concepts of radiometry and radiometric instrumentation. We find radiometry is often a deceptively difficult concept for students to master. To address this, we have developed an experiment in our optics-laboratory coursework to help them gain this mastery. A Fourier-transform infrared spectrometer (FTS) is used to collect spectral data from an unknown sample. FTS calibration and data collection are discussed here, as are the two specific samples …
Relative Vectoring Using Dual Object Detection For Autonomous Aerial Refueling, Derek B. Worth, Jeffrey L. Choate, James Lynch, Scott L. Nykl, Clark N. Taylor
Relative Vectoring Using Dual Object Detection For Autonomous Aerial Refueling, Derek B. Worth, Jeffrey L. Choate, James Lynch, Scott L. Nykl, Clark N. Taylor
Faculty Publications
Once realized, autonomous aerial refueling will revolutionize unmanned aviation by removing current range and endurance limitations. Previous attempts at establishing vision-based solutions have come close but rely heavily on near perfect extrinsic camera calibrations that often change midflight. In this paper, we propose dual object detection, a technique that overcomes such requirement by transforming aerial refueling imagery directly into receiver aircraft reference frame probe-to-drogue vectors regardless of camera position and orientation. These vectors are precisely what autonomous agents need to successfully maneuver the tanker and receiver aircraft in synchronous flight during refueling operations. Our method follows a common 4-stage process …
The Behavior Of ½⟨111⟩ Screw Dislocations In W–Mo Alloys Analyzed Through Atomistic Simulations, Lucas A. Heaton, Kevin Chu, Adib J. Samin
The Behavior Of ½⟨111⟩ Screw Dislocations In W–Mo Alloys Analyzed Through Atomistic Simulations, Lucas A. Heaton, Kevin Chu, Adib J. Samin
Faculty Publications
Analyzing plastic flow in refractory alloys is relevant to many different commercial and technological applications. In this study, screw dislocation statics and dynamics were studied for various compositions of the body-centered cubic binary alloy tungsten–molybdenum (W–Mo). The core structure did not appear to change for different alloy compositions, consistent with the literature. The pure tungsten and pure molybdenum samples had the lowest plastic flow, while the highest dislocation velocities were observed for equiatomic, W0.5Mo0.5 alloys. In general, dislocation velocities were found to largely align with a well-established dislocation mobility phenomenological model supporting two discrete dislocation mobility regimes, …
Improving The Practical Skills Of Stem Students At A Historically Black College And University (Hbcu), Yasser Ismail, Phyllis Okwan, Fred Lacy
Improving The Practical Skills Of Stem Students At A Historically Black College And University (Hbcu), Yasser Ismail, Phyllis Okwan, Fred Lacy
Faculty Publications
Improving the practical skills of Science, Technology, Engineering and Mathematics (STEM) students at a historically black college and university (HBCU) was done by implementing a transformative teaching model. The model was implemented on undergraduate students of different educational levels in the Electrical Engineering (EE) Department at HBCU. The model was also extended to carefully chosen high and middle schools. These middle and high school students serve as a pipeline to the university, with a particular emphasis on fostering growth within the EE Department. The model aligns well with the core mission of the EE Department, aiming to enhance the theoretical …
Detecting Substance Use Disorder Using Social Media Data And Dark Web: Time And Knowledge Aware Study, Usha Lokala, Orchid Chetia Phukan, Triyasha Ghosh Dastidar, Francois Lamy, Raminta Daniulaityte, Amit Sheth
Detecting Substance Use Disorder Using Social Media Data And Dark Web: Time And Knowledge Aware Study, Usha Lokala, Orchid Chetia Phukan, Triyasha Ghosh Dastidar, Francois Lamy, Raminta Daniulaityte, Amit Sheth
Faculty Publications
Opioid and substance misuse is rampant in the United States today, with the phenomenon known as the "opioid crisis". The relationship between substance use and mental health has been extensively studied, with one possible relationship being: substance misuse causes poor mental health. However, the lack of evidence on the relationship has resulted in opioids being largely inaccessible through legal means. This study analyzes the substance use posts on social media with opioids being sold through crypto market listings. We use the Drug Abuse Ontology, state-of-the-art deep learning, and knowledge-aware BERT-based models to generate sentiment and emotion for the social media …
Residual Stress Generation In Additive Manufacturing Of Complex Lattice Geometries, Katie Bruggeman, Nathan Klingbeil, Anthony N. Palazotto
Residual Stress Generation In Additive Manufacturing Of Complex Lattice Geometries, Katie Bruggeman, Nathan Klingbeil, Anthony N. Palazotto
Faculty Publications
Residual stresses developed during additive manufacturing (AM) can influence the mechanical performance of structural components in their intended applications. In this study, thermomechanical residual stress simulations of the laser powder bed fusion (LPBF) process are conducted for both simplified (plate and cube-shaped) geometries as well as five complex lattice geometries fabricated with Inconel 718. These simulations are conducted with the commercial software package Simufact Additive©, which uses a nonlinear finite element analysis and layer-by-layer averaging approach in determining residual stresses. To verify the efficacy of the Simufact Additive© simulations, numerical results for the plate and cube-shape geometries are analyzed for …