Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

2013

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 4021 - 4050 of 7293

Full-Text Articles in Engineering

Fate Of Malathion In An Activated Sludge Municipal Wastewater Treatment System, Edward B. Walters Mar 2013

Fate Of Malathion In An Activated Sludge Municipal Wastewater Treatment System, Edward B. Walters

Theses and Dissertations

Organophosphate compounds are used as pesticides and in chemical warfare agents such as nerve agents. VX (O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate) is one of the most toxic and environmentally persistent of these nerve agents. This research examined the fate of malathion, a pesticide and surrogate of VX (O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate), in bench-scale activated sludge (AS) sequencing batch reactors. Sorption kinetics and sorption equilibrium isotherm experiments indicate that sorption to AS biomass was not a statistically important removal mechanism. However, approximately 90% of the initial 4.25 mg L-1 malathion concentration degraded primarily via heterotrophic activity.

Go to article

An Investigation And Analysis Of The Vestibulo-Ocular Reflex In A Vibration Environment, Daniel J. Uribe Mar 2013

An Investigation And Analysis Of The Vestibulo-Ocular Reflex In A Vibration Environment, Daniel J. Uribe

Theses and Dissertations

Forty years of innovations have greatly improved Helmet-Mounted Displays (HMDs) and their integration into military systems. However, a significant issue with HMDs is the effect of vibration and the associated Vestibulo-Ocular Reflex (VOR). When a human’s head is subject to low-frequency vibration, the VOR stabilizes the eye with respect to objects in the external environment. However, this response is inappropriate in HMDs as the display moves with the user’s head and the VOR blurs the image as it is projected on the human retina. Current compensation techniques suggest increasing the size of displayed graphics or text to compensate for the …

Go to article

Calibration And Extension Of A Discrete Event Operations Simulation Modeling Multiple Un-Manned Aerial Vehicles Controlled By A Single Operator, Jonathan W. Welborn Mar 2013

Calibration And Extension Of A Discrete Event Operations Simulation Modeling Multiple Un-Manned Aerial Vehicles Controlled By A Single Operator, Jonathan W. Welborn

Theses and Dissertations

This research improved a simulation that models a single operator responsible for multiple UAV rovers. The improvement calibrated the model by increasing the realism of its expected time that the target will be within the field of view of a UAV's camera and how much of that will be observed by an operator that has multiple tasks to perform throughout the mission. The calibration was derived from multiple flight tests, by using a Field of View Algorithm in MATLAB and by visually recording times for loiter loops by hand. It was determined that the target will be within the field …

Go to article

Evaluating The Effectiveness Of Ip Hopping Via An Address Routing Gateway, Ryan A . Morehart Mar 2013

Evaluating The Effectiveness Of Ip Hopping Via An Address Routing Gateway, Ryan A . Morehart

Theses and Dissertations

This thesis explores the viability of using Internet Protocol (IP) address hopping in front of a network as a defensive measure. This research presents a custom gateway-based IP hopping solution called Address Routing Gateway (ARG) that acts as a transparent IP address hopping gateway. This thesis tests the overall stability of ARG, the accuracy of its classifications, the maximum throughput it can support, and the maximum rate at which it can change IPs and still communicate reliably. This research is accomplished on a physical test network with nodes representing the types of hosts found on a typical, corporate-style network. Direct …

Go to article

A Study Of Dim Object Detection For The Space Surveillance Telescope, Stephen D. Maksim Mar 2013

A Study Of Dim Object Detection For The Space Surveillance Telescope, Stephen D. Maksim

Theses and Dissertations

Current methods of dim object detection for space surveillance make use of a Gaussian log-likelihood-ratio-test-based detector that only considers the probability that a single point in an image resulted from the propagation of a point source through space. This paper proposes the application of a correlating Gaussian log-likelihood-ratio-test-based detector, which makes use of all the pixels in the window, to the arena of dim object detection. The requirements for comparing these detectors using the same threshold of detection are established. The performance of the detectors is compared using images taken by the Space Surveillance Telescope in New Mexico of a …

Go to article

The Miniaturization Of The Afit Random Noise Radar, Aaron T. Myers Mar 2013

The Miniaturization Of The Afit Random Noise Radar, Aaron T. Myers

Theses and Dissertations

Advances in technology and signal processing techniques have opened the door to using an UWB random noise waveform for radar imaging. This unique, low probability of intercept waveform has piqued the interest of the U.S. DoD as well as law enforcement and intelligence agencies alike. While AFIT's noise radar has made significant progress, the current architecture needs to be redesigned to meet the space constraints and power limitations of an aerial platform. This research effort is AFIT's first attempt at RNR miniaturization and centers on two primary objectives: 1) identifying a signal processor that is compact, energy efficient, and capable …

Go to article

Modeling Cyber Situational Awareness Through Data Fusion, Evan L. Raulerson Mar 2013

Modeling Cyber Situational Awareness Through Data Fusion, Evan L. Raulerson

Theses and Dissertations

Cyber attacks are compromising networks faster than administrators can respond. Network defenders are unable to become oriented with these attacks, determine the potential impacts, and assess the damages in a timely manner. Since the observations of network sensors are normally disjointed, analysis of the data is overwhelming and time is not spent efficiently. Automation in defending cyber networks requires a level of reasoning for adequate response. Current automated systems are mostly limited to scripted responses. Better defense tools are required. This research develops a framework that aggregates data from heterogeneous network sensors. The collected data is correlated into a single …

Go to article

Detection Optimization Of The Progressive Multi-Channel Correlation Algorithm Used In Infrasound Nuclear Treaty Monitoring, Anthony M. Runco Mar 2013

Detection Optimization Of The Progressive Multi-Channel Correlation Algorithm Used In Infrasound Nuclear Treaty Monitoring, Anthony M. Runco

Theses and Dissertations

This thesis develops methods to determine optimum detection thresholds for the Progressive Multi-Channel Correlation (PMCC) algorithm used by the International Data Centre (IDC) to perform infrasound station-level nuclear-event detection. Receiver Operating Characteristic (ROC) curve analysis is used with real ground truth data to determine the trade-off between the probability of detection (P sub D) and the false alarm rate (FAR) at various consistency detection thresholds. Further, statistical detection theory via maximum a posteriori and Bayes cost approaches is used to determine station-level optimum family size thresholds of grouped detection pixels with similar signal attributes (i.e. trace velocity, azimuth, time of …

Go to article

Characterization And Dynamic Analysis Of Long-Cavity Multi-Section Gain-Levered Quantum-Dot Lasers, John R. Schmidt Mar 2013

Characterization And Dynamic Analysis Of Long-Cavity Multi-Section Gain-Levered Quantum-Dot Lasers, John R. Schmidt

Theses and Dissertations

This research investigates the impact of different device architectures on the frequency response of long-cavity multi-section quantum-dot lasers. This work focused on a novel 8.3-mm multi-section quantum-dot device which possessed the flexibility to be configured either as a single- or multi-section device having gain-to-modulation section ratios of 14:2 and 15:1. The long-cavity device design facilitated the testing of increased gain-to-modulation section length ratios previously unexplored in the context of the gain-lever effect. The investigation of the gain-lever effect showed improvements to both the modulation efficiency and modulation bandwidth of the device under test. The modulation efficiency and modulation bandwidth were …

Go to article

Rf Emitter Tracking And Intent Assessment, Benjamin J. Kuhar Mar 2013

Rf Emitter Tracking And Intent Assessment, Benjamin J. Kuhar

Theses and Dissertations

Current research in employing pattern recognition techniques in a wireless sensor network (WSN) to detect anomalous or suspicious behavior is limited. The purpose of this research was to determine the feasibility of an accurate tracking and intent assessment system of unknown or foreign radio frequency (RF) emitters in close proximity to and within military installations as a method for physical security. 22 position tracks were collected using a hand-held Global Positioning System (GPS) unit and a training data set from five different features was generated for each position track. Each collected position track was individually classified as suspicious or non-suspicious …

Go to article

Sensitivity Analysis Of An Automated Calibration Routine For Airborne Cameras, Philip E. Lorenzini Mar 2013

Sensitivity Analysis Of An Automated Calibration Routine For Airborne Cameras, Philip E. Lorenzini

Theses and Dissertations

Given a known aircraft location, a set of camera calibration parameters can be used to correlate features in an image with ground locations. Previously, these calibration parameters were obtained during preflight with a lengthy calibration process. A method to automate this calibration using images taken with an aircraft mounted camera and position and attitude data is developed. This thesis seeks to determine a partial set of circumstances that affect the accuracy of the calibration results through simulation and experimental flight test. A software simulator is developed in which to test an array of aircraft maneuvers, camera orientations, and noise injection. …

Go to article

Error Characterization Of Vision-Aided Navigation Systems, Daniel A . Marietta Mar 2013

Error Characterization Of Vision-Aided Navigation Systems, Daniel A . Marietta

Theses and Dissertations

The goal of this work is to characterize the errors committed by an Image Aided Navigation (IAN) algorithm that has been developed for use as a navigation tool in GPS denied areas. The filter under study was developed by the Air Force Institute of Technology's Advanced Navigation Technology center, and has been the focus of numerous research efforts. Unfortunately, these studies have all been based on single runs or simulations, and such results may not be indicative of the true filter performance. This problem extends to IAN publications in general; no analysis of IAN based upon a sizable real world …

Go to article

Rootkit Detection Using A Cross-View Clean Boot Method, Bridget N. Flatley Mar 2013

Rootkit Detection Using A Cross-View Clean Boot Method, Bridget N. Flatley

Theses and Dissertations

In cyberspace, attackers commonly infect computer systems with malware to gain capabilities such as remote access, keylogging, and stealth. Many malware samples include rootkit functionality to hide attacker activities on the target system. After detection, users can remove the rootkit and associated malware from the system with commercial tools. This research describes, implements, and evaluates a clean boot method using two partitions to detect rootkits on a system. One partition is potentially infected with a rootkit while the other is clean. The method obtains directory listings of the potentially infected operating system from each partition and compares the lists to …

Go to article

Improving Bandwidth Utilization In A 1 Tbps Airborne Mimo Communications Downlink, Jonathan D. Hill Mar 2013

Improving Bandwidth Utilization In A 1 Tbps Airborne Mimo Communications Downlink, Jonathan D. Hill

Theses and Dissertations

FEC techniques are compared for different MIMO configurations of a high altitude, extremely wide bandwidth radio frequency downlink. Monte Carlo simulations are completed in MATLAB® with the aim of isolating the impacts of turbo codes and LDPC codes on system throughput and error performance. The system is modeled as a transmit-only static array at an altitude of 60,000 feet, with no interferers in the channel. Transmissions are received by a static receiver array. Simulations attempt to determine what modulation types should be considered for practical implementation, and what FEC codes enable these modulation schemes. The antenna configurations used in this …

Go to article

Automatic Modulation Classification Of Common Communication And Pulse Compression Radar Waveforms Using Cyclic Features, John A . Hadjis Mar 2013

Automatic Modulation Classification Of Common Communication And Pulse Compression Radar Waveforms Using Cyclic Features, John A . Hadjis

Theses and Dissertations

This research develops a feature-based MAP classification system and applies it to classify several common pulse compression radar and communication modulations. All signal parameters are treated as unknown to the classifier system except SNR and the signal carrier frequency. The features are derived from estimated duty cycle, cyclic spectral correlation, and cyclic cumulants. The modulations considered in this research are BPSK, QPSK, 16-QAM, 64-QAM, 8-PSK, and 16-PSK communication modulations, as well as Barker coded, Barker coded, Barker coded, Frank coded, Px49 coded, and LFM pulse compression modulations. Simulations show that average correct signal modulation type classification %C 90% is achieved …

Go to article

File Carving And Malware Identification Algorithms Applied To Firmware Reverse Engineering, Karl A . Sickendick Mar 2013

File Carving And Malware Identification Algorithms Applied To Firmware Reverse Engineering, Karl A . Sickendick

Theses and Dissertations

Modern society depends on critical infrastructure (CI) managed by Programmable Logic Controllers (PLCs). PLCs depend on firmware, though firmware security vulnerabilities and contents remain largely unexplored. Attackers are acquiring the knowledge required to construct and install malicious firmware on CI. To the defender, firmware reverse engineering is a critical, but tedious, process. This thesis applies machine learning algorithms, from the le carving and malware identification fields, to firmware reverse engineering. It characterizes the algorithms' performance. This research describes and characterizes a process to speed and simplify PLC firmware analysis. The system partitions binary firmwares into segments, labels each segment with …

Go to article

Adaptations And Analysis Of The Afit Noise Radar Network For Indoor Navigation, Russell D. Wilson Iv Mar 2013

Adaptations And Analysis Of The Afit Noise Radar Network For Indoor Navigation, Russell D. Wilson Iv

Theses and Dissertations

After several years of development, the AFIT Noise Radar Network (NoNET) has proven to be an extremely versatile system for many standard radar functions. This pallet of capabilities includes through the wall target tracking capabilities due to its wide bandwidth and UHF operations. Utilizing White Gaussian Noise as its waveform, the NoNET can operate at much lower power levels than other comparable systems while remaining extremely covert. In an effort to explore new applications, the question arose could the NoNET provide a viable option for navigation capability in GPS denied and indoor environments? This research aims to provide proof of …

Go to article

Feasibility Analysis On The Utilization Of The Iridium Satellite Communications Network For Resident Space Objects In Low Earth Orbit, John R. Claybrook Mar 2013

Feasibility Analysis On The Utilization Of The Iridium Satellite Communications Network For Resident Space Objects In Low Earth Orbit, John R. Claybrook

Theses and Dissertations

In recent years, space has become more congested and contested, particularly in low Earth orbit (LEO), generating the need for a low-latency capability to provide precise orbital knowledge and accurate space situational awareness information. This thesis investigates the feasibility of resident space objects (RSOs) in LEO communicating continuously with ground operators or users through the Iridium Satellite Communications Network. Due to the problem's complexity and required time for computation, a test-industry technique called Design of Experiments is implemented in order to efficiently study the feasibility of the communication link. Specifically, an optimal response surface method is chosen to design the …

Go to article

Biaxial (Tension-Torsion) Testing Of An Oxide/Oxide Ceramic Matrix Composite, Joseph M. Derienzo Mar 2013

Biaxial (Tension-Torsion) Testing Of An Oxide/Oxide Ceramic Matrix Composite, Joseph M. Derienzo

Theses and Dissertations

High temperatures and structural loads in advanced aerospace structures often result in complex loading conditions. This study is focused on biaxial (tension-torsion) testing of an oxide-oxide porous matrix ceramic matrix composite (CMC) (NextelTM 720/AS) thin wall tube with a novel involute layup. Tests included pure torsion and biaxial (tension- torsion) loading. Strain gages were used in addition to digital image correlation (DIC) to measure strains and to detect crack initiation and propagation. Room temperature and 1100°C uniaxial tests were performed in a build up approach prior to biaxial (tension-torsion) testing. Double-notch shear (DNS) specimens were tested at 1100°C in air …

Go to article

Application Of Finite Element To Evaluate Material With Small Modulus Of Elasticity, Boyce H. Dauby Mar 2013

Application Of Finite Element To Evaluate Material With Small Modulus Of Elasticity, Boyce H. Dauby

Theses and Dissertations

This thesis describes the development of a series of models utilizing the commercial finite element suite ABAQUS specifically to apply towards the study of biological tissue. The end goal is to be able to obtain the material properties of the Manducca Sexta, a biological inspiration for flapping wing micro-air vehicles. Two finite element models were used to analyze the results of two prior studies of other researchers. A flat punch elastic model examined boundary effects and confirmed that the point of indentation was far enough removed from the boundary. The hyperelastic spherical indentation experiment examined the effects of coefficient of …

Go to article

Computational Simulation Of Explosively Generated Pulsed Power Devices, Mollie C. Drumm Mar 2013

Computational Simulation Of Explosively Generated Pulsed Power Devices, Mollie C. Drumm

Theses and Dissertations

Technology and size constraints have limited the development of the end game mechanisms of today's modern military weapons. A smaller, more efficient means of powering these devices is needed, and explosive pulsed power devices could be that answer. While most prior research has been in the experimental field, there is a need for more theory-based research and a computer modeling capability. The objective of this research was to use experimental data collected by the US Army at Redstone Arsenal from their ferroelectric generator (FEG) design in combination with the ALEGRA-EMMA code to develop a computer model that can accurately represent …

Go to article

Effects Of Temperature On The Performance Of A Small Internal Combustion Engine At Altitude, Travis D. Husaboe Mar 2013

Effects Of Temperature On The Performance Of A Small Internal Combustion Engine At Altitude, Travis D. Husaboe

Theses and Dissertations

The effects of atmospheric pressure and temperature variations on the performance of small internal combustion (IC) engines operating at altitudes significantly above sea level are not widely documented. Using an altitude chamber and fuel-injected twostroke engine, data were collected while varying air temperature along with pressure. The peak engine power was 4.1 kW at roughly sea level standard conditions and dropped to 3.5 kW at the standard conditions for an altitude of 1.5 km. At a combination of pressure and temperature corresponding to an altitude of 3 km, peak power fell further to 2.5 kW. The combined effects of standard …

Go to article

A Study Of The Thermal Environment Developed By A Traveling Slipper At High Velocity, Kathleen H. Le Mar 2013

A Study Of The Thermal Environment Developed By A Traveling Slipper At High Velocity, Kathleen H. Le

Theses and Dissertations

The research presented in this thesis is developed from the relative sliding motion of a traveling slipper and stationary rail at the Holloman High Speed Test Track located at Holloman AFB, NM. The high velocity condition of the slipper traveling down the rail creates a thermal environment that is of interest to the researchers at the Air Force Institute of Technology. The high temperatures coupled with high velocity leads to a non-linear problem known as melt wear. The goal of this research is to characterize the amount of heat flow going into the slipper as it traverses the rail and …

Go to article

Experimental Characterization Of The Structural Dynamics And Aero-Structural Sensitivity Of A Hawkmoth Wing Toward The Development Of Design Rules For Flapping Wing Micro Air Vehicles, Aaron G. Norris Mar 2013

Experimental Characterization Of The Structural Dynamics And Aero-Structural Sensitivity Of A Hawkmoth Wing Toward The Development Of Design Rules For Flapping Wing Micro Air Vehicles, Aaron G. Norris

Theses and Dissertations

A case is made for why the structures discipline must take on a more central role in the research and design of flapping-wing micro-air-vehicles, especially if research trends continue toward bio-inspired, insect-sized flexible wing designs. In making the case, the eigenstructure of the wing emerges as a key structural metric for consideration. But with virtually no structural dynamic data available for actual insect wings, both engineered and computational wing models that have been inspired by biological analogs have no structural truth models to which they can be anchored. An experimental framework is therefore developed herein for performing system identification testing …

Go to article

Porous Emitter Colloid Thruster Performance Characterization Using Optical Techniques, Eric T. Wolf Mar 2013

Porous Emitter Colloid Thruster Performance Characterization Using Optical Techniques, Eric T. Wolf

Theses and Dissertations

This research focuses on experimentally characterizing the performance parameters of a colloid thruster with porous emitters through optical techniques. Porous emitters are different than traditional needle emitters in how they allow a variation in the number and size of Taylor Cones throughout a range of propellant volumetric flow rate conditions. An algorithm is created to calculate the estimated minimum and maximum number of emitter sites based on magnified images of the porous emitter heads. Theoretical thruster performance parameters are then established from the estimated number of emitter sites. Experimental techniques for measuring the thrust and exhaust exit velocity are proposed. …

Go to article

Training Maneuver Evaluation For Reduced Order Modeling Of Stability & Control Properties Using Computational Fluid Dynamics, Craig C. Porter Mar 2013

Training Maneuver Evaluation For Reduced Order Modeling Of Stability & Control Properties Using Computational Fluid Dynamics, Craig C. Porter

Theses and Dissertations

System identification has long been used as a tool for flight test engineers to characterize systems under test; however, the inputs to these characterization activities have previously been limited to wind tunnel and flight test data. There has been a recent effort to incorporate computational fluid dynamics (CFD) into the system identification process. An integral piece of the process is the simulation of training maneuvers utilizing CFD. Up until now, the suitability of particular training maneuvers has been assessed by comparing the reduced model to known results. This research strives to recommend a set of parameters to be used in …

Go to article

Computer Based Behavioral Biometric Authentication Via Multi-Modal Fusion, Kyle O. Bailey Mar 2013

Computer Based Behavioral Biometric Authentication Via Multi-Modal Fusion, Kyle O. Bailey

Theses and Dissertations

Biometric computer authentication has an advantage over password and access card authentication in that it is based on something you are, which is not easily copied or stolen. One way of performing biometric computer authentication is to use behavioral tendencies associated with how a user interacts with the computer. However, behavioral biometric authentication accuracy rates are much larger then more traditional authentication methods. This thesis presents a behavioral biometric system that fuses user data from keyboard, mouse, and Graphical User Interface (GUI) interactions. Combining the modalities results in a more accurate authentication decision based on a broader view of the …

Go to article

High Frequency Magnetic Field Direction Finding Using Mgl-S8a B-Dot Sensors, Michael D. Archer Mar 2013

High Frequency Magnetic Field Direction Finding Using Mgl-S8a B-Dot Sensors, Michael D. Archer

Theses and Dissertations

Aircraft based direction finding (DF) in the high frequency (HF) band is difficult due to the aircraft's size with respect to wavelength and limited azimuthal resolution. A B-dot sensor is useful for detection of the time varying magnetic field and offers improved integration into an aircraft. What the B-dot sensor gains in integration it gives up in sensitivity because it is designed for frequencies above 5 GHz. Design of an airborne HFDF array using Bdot sensors is based in maximizing the physical extent of the array and eliminating multiple main beams. The goals of this research are to complete a …

Go to article

Machine Conscious Architecture For State Exploitation And Decision Making, Mark M. Derriso Mar 2013

Machine Conscious Architecture For State Exploitation And Decision Making, Mark M. Derriso

Theses and Dissertations

This research addressed a critical limitation in the area of computational intelligence by developing a general purpose architecture for information processing and decision making. Traditional computational intelligence methods are best suited for well-defined problems with extensive, long-term knowledge of the environmental and operational conditions the system will encounter during operation. These traditional approaches typically generate quick answers (i.e., reflexive responses) using pattern recognition methods. Most pattern recognition techniques are static processes which consist of a predefined series of computations. For these pattern recognition approaches to be effective, training data is required from all anticipated environments and operating conditions. The proposed …

Go to article

Laser Illuminated Imaging: Multiframe Beam Tilt Tracking And Deconvolution Algorithm, David J. Becker Mar 2013

Laser Illuminated Imaging: Multiframe Beam Tilt Tracking And Deconvolution Algorithm, David J. Becker

Theses and Dissertations

A laser-illuminated imaging system operating in the presence of atmospheric turbulence will encounter several sources of noise and diffraction induced errors. As the beam propagates, turbulence induced tilt will cause the beam to wander off axis from the target. This is especially troublesome when imaging satellites, since most turbulence is closer to the Earth's surface and greatly affects the beam in the early stages of propagation. Additionally, the returning beam convolved with the target will encounter turbulence induced tilt that appears as apparent movement of the target between image frames. This results in varying beam intensities at the target surface …

Go to article

First Prev Next Last