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Articles 78751 - 78780 of 196417
Full-Text Articles in Engineering
Estimating Defensive Cyber Operator Decision Confidence, Markus M. Borneman
Estimating Defensive Cyber Operator Decision Confidence, Markus M. Borneman
Theses and Dissertations
As technology continues to advance the domain of cyber defense, signature and heuristic detection mechanisms continue to require human operators to make judgements about the correctness of machine decisions. Human cyber defense operators rely on their experience, expertise, and understanding of network security, when conducting cyber-based investigations, in order to detect and respond to cyber alerts. Ever growing quantities of cyber alerts and network traffic, coupled with systemic manpower issues, mean no one has the time to review or change decisions made by operators. Since these cyber alert decisions ultimately do not get reviewed again, an inaccurate decision could cause …
Progressive Network Deployment, Performance, And Control With Software-Defined Networking, Daniel J. Casey
Progressive Network Deployment, Performance, And Control With Software-Defined Networking, Daniel J. Casey
Theses and Dissertations
The inflexible nature of traditional computer networks has led to tightly-integrated systems that are inherently difficult to manage and secure. New designs move low-level network control into software creating software-defined networks (SDN). Augmenting an existing network with these enhancements can be expensive and complex. This research investigates solutions to these problems. It is hypothesized that an add-on device, or "shim" could be used to make a traditional switch behave as an OpenFlow SDN switch while maintaining reasonable performance. A design prototype is found to cause approximately 1.5% reduction in throughput for one ow and less than double increase in latency, …
Assessing The Competing Characteristics Of Privacy And Safety Within Vehicular Ad Hoc Networks, Jacob W. Connors
Assessing The Competing Characteristics Of Privacy And Safety Within Vehicular Ad Hoc Networks, Jacob W. Connors
Theses and Dissertations
The introduction of Vehicle-to-Vehicle (V2V) communication has the promise of decreasing vehicle collisions, congestion, and emissions. However, this technology places safety and privacy at odds; an increase of safety applications will likely result in the decrease of consumer privacy. The National Highway Traffic Safety Administration (NHTSA) has proposed the Security Credential Management System (SCMS) as the back end infrastructure for maintaining, distributing, and revoking vehicle certificates attached to every Basic Safety Message (BSM). This Public Key Infrastructure (PKI) scheme is designed around the philosophy of maintaining user privacy through the separation of functions to prevent any one subcomponent from identifying …
Modeling A Space-Based Quantum Link, Alexander W. Duchane
Modeling A Space-Based Quantum Link, Alexander W. Duchane
Theses and Dissertations
Quantum sources and single photon detectors have improved, allowing quantum algorithms for communication, encryption, computing, and sensing to transition from theory and small-scale laboratory experiments to field experiments. One such quantum algorithm, Quantum Key Distribution, uses optical pulses to generate shared random bit strings between two locations. These shared bit strings can be turned into encryption keys to be used as a one-time-pad or integrated with symmetric encryption techniques such as the Advanced Encryption Standard. This method of key generation and encryption is resistant to future advances in quantum computing which significantly degrade the effectiveness of current asymmetric key sharing …
Assured Android Execution Environments, Brandon P. Froberg
Assured Android Execution Environments, Brandon P. Froberg
Theses and Dissertations
Current cybersecurity best practices, techniques, tactics and procedures are insufficient to ensure the protection of Android systems. Software tools leveraging formal methods use mathematical means to assure both a design and implementation for a system and these methods can be used to provide security assurances. The goal of this research is to determine methods of assuring isolation when executing Android software in a contained environment. Specifically, this research demonstrates security properties relevant to Android software containers can be formally captured and validated, and that an implementation can be formally verified to satisfy a corresponding specification. A three-stage methodology called "The …
Mitigating The Effects Of Boom Occlusion On Automated Aerial Refueling Through Shadow Volumes, Zachary C. Paulson
Mitigating The Effects Of Boom Occlusion On Automated Aerial Refueling Through Shadow Volumes, Zachary C. Paulson
Theses and Dissertations
In flight refueling of Unmanned Aerial Vehicles (UAVs) is critical to the United States Air Force (USAF). However, the large communication latency between a ground-based operator and his/her remote UAV makes docking with a refueling tanker unsafe. This latency may be mitigated by leveraging a tanker-centric stereo vision system. The vision system observes and computes an approaching receiver's relative position and orientation offering a low-latency, high frequency docking solution. Unfortunately, the boom -- an articulated refueling arm responsible for physically pumping fuel into the receiver -- occludes large portions of the receiver especially as the receiver approaches and docks with …
Stereo Vision: A Comparison Of Synthetic Imagery Vs. Real World Imagery For The Automated Aerial Refueling Problem, Nicholas J. Seydel
Stereo Vision: A Comparison Of Synthetic Imagery Vs. Real World Imagery For The Automated Aerial Refueling Problem, Nicholas J. Seydel
Theses and Dissertations
Missions using unmanned aerial vehicles have increased in the past decade. Currently, there is no way to refuel these aircraft. Accomplishing automated aerial refueling can be made possible using the stereo vision system on a tanker. Real world experiments for the automated aerial refueling problem are expensive and time consuming. Currently, simulations performed in a virtual world have shown promising results using computer vision. It is possible to use the virtual world as a substitute environment for the real world. This research compares the performance of stereo vision algorithms on synthetic and real world imagery.
A Surprising Symbiosis: Examining The Mutualism In Department Of Defense Conservation Partnerships, Andrew J. Lankow
A Surprising Symbiosis: Examining The Mutualism In Department Of Defense Conservation Partnerships, Andrew J. Lankow
Theses and Dissertations
Because of the DoD’s unique and significant role in the conservation of natural resources, military leaders and natural resource managers need a trail guide to frame interagency collaboration in a way that shapes productive partnerships. The purpose of this research was to examine successful DoD conservation partnerships in order to identify key success factors (KSFs) and the most prominent challenges faced, and how those characteristics enable the accomplishment of each partner’s objectives. The research questions were answered through a comprehensive literature review and the use of the multiple-case study method. 19 key informants from three installations participated in semi-structured interviews, …
Managing Supply Discrepancies: The Effect Of Performance Measurement And Feedback On Order Fulfillment Quality, Michael J. Weber
Managing Supply Discrepancies: The Effect Of Performance Measurement And Feedback On Order Fulfillment Quality, Michael J. Weber
Theses and Dissertations
Extensive research on the impact of shipping and packaging errors in the private sector finds numerous negative outcomes, including reduced customer satisfaction, reduced customer loyalty, and lower profitability. However, little research has been done examining the impact of order fulfillment errors on military operations. The purpose of this research is to quantify the impact of supply discrepancy reports (SDRs) on military aircraft readiness metrics, including cannibalizations, not mission capable supply (NMCS) hours, aircraft availability and MICAP hours. Results show SDRs significantly impact aircraft readiness metrics in seven of the fifteen analyses conducted. Additionally, a quasi-experimental study is implemented at DLA …
Design And Test Of A Uav Swarm Architecture Over A Mesh Ad-Hoc Network, Timothy J. Allen
Design And Test Of A Uav Swarm Architecture Over A Mesh Ad-Hoc Network, Timothy J. Allen
Theses and Dissertations
The purpose of this research was to develop a testable swarm architecture such that the swarm of UAVs collaborate as a team rather than acting as several independent vehicles. Commercial-off-the-shelf (COTS) components were used as they were low-cost, readily available, and previously proven to work with at least two networked UAVs. Initial testing was performed via software-in-the-loop (SITL) demonstrating swarming of three simulated multirotor aircraft, then transitioned to real hardware. The architecture was then tested in an outdoor nylon netting enclosure. Command and control (C2) was provided by software implementing an enhanced version of Reynolds’ flocking rules via an onboard …
United States Air Force Applications Of Unmanned Aerial Systems: Modernizing Airfield Damage Assessment, Samuel M. Clark
United States Air Force Applications Of Unmanned Aerial Systems: Modernizing Airfield Damage Assessment, Samuel M. Clark
Theses and Dissertations
Modernizing airfield damage assessment has long been a priority mission at the Air Force Civil Engineer Center (AFCEC). Previously, AFCEC has made advances to expedite unexploded ordnance (UXO) neutralization and pavement repair. Missing from these initiatives is the initial assessment component. This thesis expands the idea of using Small Unmanned Aerial Systems (SUAS), applies it to the Air Force mission, and provides SUAS vehicle configuration and sensor recommendations. In this study, 25 civil engineer officers reviewed airfield imagery gathered using two small air vehicles. For the first review, participants attempted to identify UXOs and foreign object debris (FOD) in a …
Building Evidence The Federal Aviation Administration's Uas Safety Strategy Needs Improvement, Ryan J. Wallace, Tom Haritos, John Robbins
Building Evidence The Federal Aviation Administration's Uas Safety Strategy Needs Improvement, Ryan J. Wallace, Tom Haritos, John Robbins
International Journal of Aviation, Aeronautics, and Aerospace
The growth of unmanned aircraft operations within the National Airspace System (NAS) reveal an uptick of alarming safety indicators that suggest unmanned aircraft system (UAS) regulatory policy may require adjustment. Recent reports of aircraft collisions with UAS, an increase in pilot-reported near-misses, and research findings that indicate UAS platforms are capable of causing structural damage to aircraft suggest safe and effective UAS integration may not be proceeding as planned. The authors examine several safety indicators within the context of Heinrich’s Triangle to reveal the UAS industry’s susceptibility to evolving safety-related problems.
Assessment Of Drinking Water Quality Management And A Treatment Feasibility Study For Brick By Brick Water Storage Tanks In Rakai Uganda, James V. Murduca
Assessment Of Drinking Water Quality Management And A Treatment Feasibility Study For Brick By Brick Water Storage Tanks In Rakai Uganda, James V. Murduca
USF Tampa Graduate Theses and Dissertations
Reliable access to safe drinking water is one necessity for humans to live without concern for major health risks. The overall goal of this research is to improve the public health, through improved drinking water, for communities in the Rakai District in Uganda, directly, and other communities in the world, indirectly, via dissemination of knowledge. This study specifically assessed the knowledge of drinking water quality in regards to public health, their sanitation measures, and water treatment methods for users of Brick by Brick rainwater harvesting tanks in the Rakai District (N = 28) by using a knowledge, attitudes, and practice …
Promoter Effects On Iron-Based, Sba-15 Supported Ultra-High Temperature Fischer- Tropsch Catalysts, David P. Weber
Promoter Effects On Iron-Based, Sba-15 Supported Ultra-High Temperature Fischer- Tropsch Catalysts, David P. Weber
USF Tampa Graduate Theses and Dissertations
Promoter effects on SBA-15 supported iron Fischer-Tropsch catalysts were investigated for their potential to improve high temperature catalyst performance. FTS catalysts promoted by manganese (0.15%-1.4%), copper (0.15%-1%), and potassium (0.5%-3%), with all percentages stated on the basis of mass percentage of final catalysts, were prepared and tested at 430°C and ambient pressure in a fixed bed reactor. Manganese showed the ability to promote the FT reaction, increasing both the CO conversion and the average chain length of hydrocarbon products. Compared to the unpromoted catalyst composed only of iron supported on SBA-15, 1.4%Mn (mass) promotion of 15% (mass) iron on SBA-15 …
Direct Print Additive Manufacturing Of Optical Fiber Interconnects, Roger B. Tipton
Direct Print Additive Manufacturing Of Optical Fiber Interconnects, Roger B. Tipton
USF Tampa Graduate Theses and Dissertations
High performance communications, sensing and computing systems are growing exponentially as modern life continues to rely more and more on technology. One of the factors that are currently limiting computing and transmission speeds are copper wire interconnects between devices. Optical fiber interconnects would greatly increase the speed of today’s electronic devices. In this study it has been demonstrated that by using a new Direct Print Additive Manufacturing (DPAM) process of Fused Deposition Modeling (FDM) of plastic and micro-dispensing of pastes and inks, we can 3D print single and multi-mode optical fibers in a controlled manner such that compact, 3-dimensional optical …
Graduate Outreach Services: Perspectives From Two University Library Programs, Corinne Bishop Edd, Nashieli Marcano Phd
Graduate Outreach Services: Perspectives From Two University Library Programs, Corinne Bishop Edd, Nashieli Marcano Phd
Transforming Libraries for Graduate Students
This session highlights graduate outreach services at the University of Central Florida and Clemson University libraries and compares institutional program approaches, outreach strategies, and the research needs of student populations in the Social Sciences and Engineering.
The presenters coordinate graduate outreach services at their institutions, and the first part of the presentation will include a discussion of each institution’s service model and each librarian’s role. Details about collaborations with campus partners and networking, f2f workshops and use of online platforms (Canvas LMS) to promote services, recruiting outreach advocates, and marketing programs will also be discussed.
The second part of the …
Measuring The Creep Behaviour Of Corrugated Board By Cascade And Individual Test Rig, Viktoria Köstner, Jörg B. Ressel, Bernd Sadlowsky, Péter Böröcz
Measuring The Creep Behaviour Of Corrugated Board By Cascade And Individual Test Rig, Viktoria Köstner, Jörg B. Ressel, Bernd Sadlowsky, Péter Böröcz
Journal of Applied Packaging Research
In this paper static and quasi-static test are conducted to determine the creep behaviour of corrugated board. This study shows a possible way to take the real loads occurring in container shipping into account. The aim of the measurements is to develop a new test option, which is in keeping with the loads occurring. Two test rigs have been developed and constructed for this purpose. These make it possible to measure the creep of corrugated board extremely precisely over a longer period in the aspect of climate chamber size and relative humidity (RH) distribution in the chamber. To increase the …
Selective Laser Melting Of Ni-Rich Niti: Selection Of Process Parameters And The Superelastic Response, Narges Shayesteh Moghaddam, Soheil Saedi, Amirhesam Amerinatanzi, Ehsan Saghaian, Ahmadreza Jahadakbar, Haluk E. Karaca, Mohammad Elahinia
Selective Laser Melting Of Ni-Rich Niti: Selection Of Process Parameters And The Superelastic Response, Narges Shayesteh Moghaddam, Soheil Saedi, Amirhesam Amerinatanzi, Ehsan Saghaian, Ahmadreza Jahadakbar, Haluk E. Karaca, Mohammad Elahinia
Mechanical Engineering Faculty Publications
Material and mechanical properties of NiTi shape memory alloys strongly depend on the fabrication process parameters and the resulting microstructure. In selective laser melting, the combination of parameters such as laser power, scanning speed, and hatch spacing determine the microstructural defects, grain size and texture. Therefore, processing parameters can be adjusted to tailor the microstructure and mechanical response of the alloy. In this work, NiTi samples were fabricated using Ni50.8Ti (at.%) powder via SLM PXM by Phenix/3D Systems and the effects of processing parameters were systematically studied. The relationship between the processing parameters and superelastic properties were investigated …
Influence Of Slm On Compressive Response Of Niti Scaffolds, Narges Shayesteh Moghaddam, Soheil Saedi, Amirhesam Amerinatanzi, Ahmadreza Jahadakbar, Sayed Ehsan Saghaian, Haluk E. Karaca, Mohammad Elahinia
Influence Of Slm On Compressive Response Of Niti Scaffolds, Narges Shayesteh Moghaddam, Soheil Saedi, Amirhesam Amerinatanzi, Ahmadreza Jahadakbar, Sayed Ehsan Saghaian, Haluk E. Karaca, Mohammad Elahinia
Mechanical Engineering Faculty Publications
Porous Nickel-Titanium shape memory alloys (NiTi-SMAs) have attracted much attention in biomedical applications due to their high range of pure elastic deformability (i.e., superelasticity) as well as their bone-level modulus of elasticity (E≈12-20 GPa). In recent years, Selective Laser Melting (SLM) has been used to produce complex NiTi components. The focus of this study is to investigate the superelasticity and compressive properties of SLM NiTi-SMAs. To this aim, several NiTi components with different level of porosities (32- 58%) were fabricated from Ni50.8Ti (at. %) powder via SLM PXM by Phenix/3D Systems, using optimum processing parameter (Laser power-P=250 W, …
Adaptive Navigation Control Primitives For Multirobot Clusters: Extrema Finding, Contour Following, Ridge/Trench Following, And Saddle Point Station Keeping, Christopher A. Kitts, Robert T. Mcdonald, Michael A. Neumann
Adaptive Navigation Control Primitives For Multirobot Clusters: Extrema Finding, Contour Following, Ridge/Trench Following, And Saddle Point Station Keeping, Christopher A. Kitts, Robert T. Mcdonald, Michael A. Neumann
Mechanical Engineering
Adaptive navigation is the process of modifying a vehicle's direction or motion path based on measurements taken while moving. When exploring a scalar field, such as the temperature or the concentration level of a pollutant across a region of interest, adaptive navigation may allow the identification of locations of interest-like the maximum temperature or the source of the pollutant-without exhaustively mapping the entire region. Adaptive navigation has been hailed as a powerful capability, and significant work has been performed to explore how such techniques can be used to find the local extreme points and follow contour levels in a field. …
Control, Characterization, And Cooling Of An Ultra-Compact Combustor, Kevin J. Demarco
Control, Characterization, And Cooling Of An Ultra-Compact Combustor, Kevin J. Demarco
Theses and Dissertations
An Ultra-Compact Combustor (UCC) is novel alternative to axial flow combustors commonly used in gas turbine engines. The UCC offers multiple benefits to engine design. First, the UCC aims to increase the thrust-to-weight ratio of an aircraft gas turbine engine by decreasing the size, and thus weight, of the engine's combustor. This is done by utilizing a Circumferential Cavity (CC) wrapped around the main core flow which hosts the combustion event, allowing a shortened combustor length. Second, within the CC, the combusting mixture is subjected to a high centrifugal loading which aids combustion by improving both flame propagation and residence …
Analytical Determination Of A Helicopter Height Velocity Diagram, Michael J. Harris
Analytical Determination Of A Helicopter Height Velocity Diagram, Michael J. Harris
Theses and Dissertations
A helicopter height velocity (HV) diagram was analytically constructed using optimal control techniques. A three degree of freedom, point-mass, dynamic model was developed and validated with flight test data. An induced velocity calculation was incorporated which addressed the effects of vortex ring state. The problem was posed as an open final time, constrained initial state, constrained final state problem, with the objective function as a weighted sum of the initial altitude and quadratic controls. This formulation was solved using direct pseudo-spectral collocation and adaptive mesh refinement as implemented by the GPOPS-II® software suite. Proper adjustment of path constraints was crucial …
Algorithms For Small Satellite Formation Flying, Robert B. Larue
Algorithms For Small Satellite Formation Flying, Robert B. Larue
Theses and Dissertations
This thesis presents algorithms for spacecraft formation flying using impulsive thrust and low-thrust methods. The general circular orbit formation initial conditions are derived in terms of equinoctial elements. Physical significance of the bounded relative motion parameters is presented for the case of general circular orbits. The developed algorithms are posed in terms of equinoctial elements for a singularity-free approach. The algorithms are assessed by numerical propagation of the inertial equations of motion with J2 and drag perturbations. Methods are presented for minimizing the ΔV required for formation initialization. An examination of the performance of open-loop and closed-loop control is provided …
Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 1000°C In Air And In Silicic Acid-Saturated Steam, Brian G. Kroeger
Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 1000°C In Air And In Silicic Acid-Saturated Steam, Brian G. Kroeger
Theses and Dissertations
Advanced SiC/SiC ceramic matrix composites (CMCs) are being considered for a variety of applications. Of interest is their ability to withstand exposure to high temperature in an aggressive oxidizing environment. The presence of steam creates such an environment. As steam traverses across a SiC/SiC composite and through cracks in the SiC matrix, it becomes saturated with silicic acid, Si(OH)4. It is essential to understand the long-term impacts and durability of SiC/SiC CMCs that have been exposed to such a demanding environment. The present research investigated creep of Hi-Nicalon™ S SiC fibers at 1000°C in air and in silicic …
Variable Speed Simulation For Accelerated Industrial Control System Cyber Training, Luke M. Bradford
Variable Speed Simulation For Accelerated Industrial Control System Cyber Training, Luke M. Bradford
Theses and Dissertations
It is important for industrial control system operators to receive quality training to defend against cyber attacks. Hands-on training exercises with real-world control systems allow operators to learn various defensive techniques and see the real-world impact of changes made to a control system. Cyber attacks and operator actions can have unforeseen effects that take a significant amount of time to manifest and potentially cause physical harm to the system, making high-fidelity training exercises time-consuming and costly. This thesis presents a method for accelerating training exercises by simulating and predicting the effects of a cyber event on a partially-simulated control system. …
Evaluation Of Resiliency In A Wide-Area Backup Protection System Via Model Checking, Kolby H. Elliot
Evaluation Of Resiliency In A Wide-Area Backup Protection System Via Model Checking, Kolby H. Elliot
Theses and Dissertations
Modern civilization relies heavily on having access to reliable power sources. Recent history has shown that present day protection systems are not adequate. Numerous backup protection (BP) systems have been proposed to mitigate the impact of primary protection system failures. Many of these novel BP systems rely on autonomous agents communicating via wide-area networks. These systems are highly complex and their control logic is based on distributed computing. Model checking has been shown to be a powerful tool in analyzing the behavior of distributed systems. In this research the model checker SPIN is used to evaluate the resiliency of an …
Securing Critical Infrastructure: A Ransomware Study, Blaine M. Jeffries
Securing Critical Infrastructure: A Ransomware Study, Blaine M. Jeffries
Theses and Dissertations
This thesis reviews traditional ransomware attack trends in order to present a taxonomy for ransomware targeting industrial control systems. After reviewing a critical infrastructure ransomware attack methodology, a corresponding response and recovery plan is described. The plan emphasizes security through redundancy, specifically the incorporation of standby programmable logic controllers. This thesis goes on to describe a set of experiments conducted to test the viability of defending against a specialized ransomware attack with a redundant controller network. Results support that specific redundancy schemes are effective in recovering from a successful attack. Further experimentation is conducted to test the feasibility of industrial …
Bandwidth Analysis Of A Tightly-Packed Crossed-Dipole Array For Satellite Communications, Lawrence J. Lee
Bandwidth Analysis Of A Tightly-Packed Crossed-Dipole Array For Satellite Communications, Lawrence J. Lee
Theses and Dissertations
A bandwidth analysis of a tightly-packed crossed-dipole array antenna is presented in this thesis. A parametric study is described which varies the element spacing in the array and the resulting change in the terminal impedances is reported. The increased mutual coupling seen by the elements as a result of smaller element spacings is shown to minimize the variation in the value of the elements terminal currents across a 0.3 GHz to 3.0 GHz frequency range. This small variation in current translates into a minimal variation in the terminal impedances for a fixed excitation voltage. This is shown to be an …
Assessment Of Structure From Motion For Reconnaissance Augmentation And Bandwidth Usage Reduction, Jonathan B. Roeber
Assessment Of Structure From Motion For Reconnaissance Augmentation And Bandwidth Usage Reduction, Jonathan B. Roeber
Theses and Dissertations
Modern militaries rely upon remote image sensors for real-time intelligence. A typical remote system consists of an unmanned aerial vehicle, or UAV, with an attached camera. A video stream is sent from the UAV, through a bandwidth-constrained satellite connection, to an intelligence processing unit. In this research, an upgrade to this method of collection is proposed. A set of synthetic images of a scene captured by a UAV in a virtual environment is sent to a pipeline of computer vision algorithms, collectively known as Structure from Motion. The output of Structure from Motion, a three-dimensional model, is then assessed in …
Flightline Heroics And The Façade Of A Healthy Common Support Equipment Fleet, Benjamin D. Bobic
Flightline Heroics And The Façade Of A Healthy Common Support Equipment Fleet, Benjamin D. Bobic
Theses and Dissertations
Access to serviceable support equipment enables aircraft maintenance crews the ability to efficiently keep assigned aircraft safe and mission capable. Current Air Force policy does not require formal management and enterprise fleet health reporting of serialized support equipment. As such, articulating funding requirements to replace equipment has been a challenge for equipment managers. To better articulate support equipment requirements, equipment managers need quantifiable support equipment data. A previous study examined the relationship between aircraft availability and support equipment availability. While finding no significant correlation, the author identifies the practices of "Frankensteining" and "Beg-Borrow-Steal" as possible reasons for the absence of …