Digital Commons Network^™

Synthesizing Time-Evolving Partially-Coherent Schell-Model Sources, Noah R. Van Zandt, Milo W. Hyde Iv, Santasri R. Bose-Pillai, David G. Voelz, Xifeng Xiao, Steven T. Fiorino

Faculty Publications

Time-evolving simulation of sources with partial spatial and temporal coherence is sometimes instructive or necessary to explain optical coherence effects. Yet, existing time-evolving synthesis techniques often require prohibitive amounts of computer memory. This paper discusses three methods for the synthesis of continuous or pulsed time-evolving sources with nearly arbitrary spatial and temporal coherence. One method greatly reduces computer memory requirements, making this type of synthesis more practical. The utility of all three methods is demonstrated via a modified form of Young's experiment. Numerical simulation and laboratory results for time-averaged irradiance are presented and compared with theory to validate the synthesis …

Air Force Institute Of Technology Research Report 2016, Graduate School Of Engineering And Management, Air Force Institute Of Technology

AFIT Documents

This Research Report presents the FY16 research statistics and contributions of the Graduate School of Engineering and Management (EN) at AFIT. AFIT research interests and faculty expertise cover a broad spectrum of technical areas related to USAF needs, as reflected by the range of topics addressed in the faculty and student publications listed in this report. In most cases, the research work reported herein is directly sponsored by one or more USAF or DOD agencies. AFIT welcomes the opportunity to conduct research on additional topics of interest to the USAF, DOD, and other federal organizations when adequate manpower and financial …

Numerical Wave Optics Investigation Of Optical Scatter From Statistically Rough Surface, Ann M. Lanari

Theses and Dissertations

The Bidirectional Reflectance Distribution Function (BRDF) describes optical scatter from rough surfaces. Numerical methods can control incident wavelength and surface features. Utilizing Fourier techniques for propagation to the far field, scatter resulting from Gaussian distributed and correlated surfaces is compared to predictions of physical optics and microfacet BRDF models. For RMS surface heights greater than /2, physical optics models are shown to be consistent with resulting scatter for incident light of wavelength 3μm to 5μm and scattered angles of −2 μrad to 2 μrad illuminated at normal incidence, while microfacet models fail to predict scatter width for shorter wavelengths.

The Fresnel Zone Light Field Spectral Imager, Francis D. Hallada

Theses and Dissertations

This thesis provides a computational model and the first experimental demonstration of a Fresnel zone light field spectral imaging (FZLFSI) system. This type of system couples an axial dispersion binary diffractive optic with light field (plenoptic) camera designs providing a snapshot spectral imaging capability. A computational model of the system was developed based on wave optics methods using Fresnel propagation. It was validated experimentally and provides excellent demonstration of system capabilities. The experimentally demonstrated system was able to synthetically refocus monochromatic images across greater than a 100nm bandwidth. Furthermore, the demonstrated system was modeled to have a full range of …

Whitelisting System State In Windows Forensic Memory Visualizations, Joshua A. Lapso, Gilbert L. Peterson, James S. Okolica

Faculty Publications

Examiners in the field of digital forensics regularly encounter enormous amounts of data and must identify the few artifacts of evidentiary value. One challenge these examiners face is manual reconstruction of complex datasets with both hierarchical and associative relationships. The complexity of this data requires significant knowledge, training, and experience to correctly and efficiently examine. Current methods provide text-based representations or low-level visualizations, but levee the task of maintaining global context of system state on the examiner. This research presents a visualization tool that improves analysis methods through simultaneous representation of the hierarchical and associative relationships and local detailed data …

Modeling, Simulation, And Performance Analysis Of Decoy State Enabled Quantum Key Distribution Systems, Logan O. Mailloux, Michael R. Grimaila, Douglas D. Hodson, Ryan D. Engle, Colin V. Mclaughlin, Gerald B. Baumgartner

Faculty Publications

Quantum Key Distribution (QKD) systems exploit the laws of quantum mechanics to generate secure keying material for cryptographic purposes. To date, several commercially viable decoy state enabled QKD systems have been successfully demonstrated and show promise for high-security applications such as banking, government, and military environments. In this work, a detailed performance analysis of decoy state enabled QKD systems is conducted through model and simulation of several common decoy state configurations. The results of this study uniquely demonstrate that the decoy state protocol can ensure Photon Number Splitting (PNS) attacks are detected with high confidence, while maximizing the system’s quantum …

Estimation Of Turbulence From Time-Lapse Imagery, Jack E. Mccrae, Santasri Bose-Pillai, Steven T. Fiorino

Faculty Publications

Atmospheric turbulence parameters are estimated for an imaging path based on time-lapse imaging results. Atmospheric turbulence causes frame-to-frame shifts of the entire image as well as parts of the image. The statistics of these shifts encode information about the turbulence strength (as characterized by Cn2, the refractive index structure function constant) along the optical path. The shift variance observed is simply proportional to the variance of the tilt of the optical field averaged over the area being tracked and averaged over the camera aperture. By presuming this turbulence follows the Kolmogorov spectrum, weighting functions, which relate the turbulence strength along …

Simulation Of Anisoplanatic Imaging Through Optical Turbulence Using Numerical Wave Propagation With New Validation Analysis, Russell C. Hardie, Jonathan D. Power, Daniel A. Lemaster, Douglas Droege, Szymon Gladysz, Santasri Bose-Pillai

Faculty Publications

We present a numerical wave propagation method for simulating imaging of an extended scene under anisoplanatic conditions. While isoplanatic simulation is relatively common, few tools are specifically designed for simulating the imaging of extended scenes under anisoplanatic conditions. We provide a complete description of the proposed simulation tool, including the wave propagation method used. Our approach computes an array of point spread functions (PSFs) for a two-dimensional grid on the object plane. The PSFs are then used in a spatially varying weighted sum operation, with an ideal image, to produce a simulated image with realistic optical turbulence degradation. The degradation …

Graduate School Of Engineering And Management Catalog 2017-2018, Graduate School Of Engineering And Management, Air Force Institute Of Technology

AFIT Documents

The Graduate Catalog represents the offerings, programs, and requirements in effect at the time of publication.

Clustering-Based Online Player Modeling, Jason M. Bindewald, Gilbert L. Peterson, Michael E. Miller

Faculty Publications

Being able to imitate individual players in a game can benefit game development by providing a means to create a variety of autonomous agents and aid understanding of which aspects of game states influence game-play. This paper presents a clustering and locally weighted regression method for modeling and imitating individual players. The algorithm first learns a generic player cluster model that is updated online to capture an individual’s game-play tendencies. The models can then be used to play the game or for analysis to identify how different players react to separate aspects of game states. The method is demonstrated on …

Developments In Capture- Γ Libraries For Nonproliferation Applications, A. M. Hurst, R. B. Firestone, B. W. Sleaford, D. L. Bleuel, M. S. Basunia, F. Becvar, T. Belgya, L. A. Bernstein, J. J. Carroll, B. Detwiler, J. E. Escher, C. Genreith, B. L. Goldblum, M. Krticka, A. G. Lerch, David A. Matters, John W. Mcclory, Stephen R. Mchale, Zs. Revay, L. Szentmiklosi, D. Turkoglu, A. Ureche, J. Vulic

Faculty Publications

The neutron-capture reaction is fundamental for identifying and analyzing the γ-ray spectrum from an unknown assembly because it provides unambiguous information on the neutron-absorbing isotopes. Nondestructive-assay applications may exploit this phenomenon passively, for example, in the presence of spontaneous-fission neutrons, or actively where an external neutron source is used as a probe. There are known gaps in the Evaluated Nuclear Data File libraries corresponding to neutron-capture γ-ray data that otherwise limit transport-modeling applications. In this work, we describe how new thermal neutron-capture data are being used to improve information in the neutron-data libraries for isotopes relevant to nonproliferation applications. We …

Generation Of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao

Faculty Publications

A simple and flexible optical system for generating electromagnetic or vector partially coherent sources or beams is presented. The alternative design controls field amplitude (beam shape), coherence, and polarization using only spatial light modulators. This improvement makes the apparatus simpler to construct and significantly increases the flexibility of vector partially coherent source generators by allowing many different types of sources to be produced without changing the physical setup. The system’s layout and theoretical foundations are thoroughly discussed. The utility and flexibility of the proposed system are demonstrated by producing a vector Schell-model and non-Schell-model source. The experimental results are compared …

Reflection Matrix Method For Controlling Light After Reflection From A Diffuse Scattering Surface, Kenneth W. Burgi

Theses and Dissertations

This research focuses on reflective inverse diffusion, which was a proof-of-concept experiment that used phase modulation to shape the wavefront of a laser causing it to refocus after reflection from a rough surface. By refocusing the light, reflective inverse diffusion has the potential to eliminate the complex radiometric model of indirect photography by creating a virtual light source at the first diffuse reflector that satisfies the line-of-sight requirement of dual photography. However, the initial reflective inverse diffusion experiments provided no mathematical background and were conducted under the premise that the process operated similarly to transmissive inverse diffusion.

In this research, …

Integrated Circuit Wear-Out Prediction And Recycling Detection Using Radio-Frequency Distinct Native Attribute Features, Randall D. Deppensmith

Theses and Dissertations

Radio Frequency Distinct Native Attribute (RF-DNA) has shown promise for detecting differences in Integrated Circuits(IC) using features extracted from a devices Unintentional Radio Emissions (URE). This ability of RF-DNA relies upon process variation imparted to a semiconductor device during manufacturing. However, internal components in modern ICs electronically age and wear out over their operational lifetime. RF-DNA techniques are adopted from prior work and applied to MSP430 URE to address the following research goals: 1) Does device wear-out impact RF-DNA device discriminability?, 2) Can device age be continuously estimated by monitoring changes in RF-DNA features?, and 3) Can device age state …

An Information Theoretic Investigation Of Complex Adaptive Supply Networks With Organizational Topologies, Joshua V. Rodewald

Theses and Dissertations

Supply networks exist throughout society in manufacturing and knowledge-intensive industries as well as many service industries. Organizations have been noted to behave as complex adaptive systems or information supply networks with both formal and informal structures. Thoroughly understanding supply network structure and behavior are critical to managing such organizations effectively, but their properties of complex adaptive systems make them more difficult to analyze and assess, forcing researchers to rely on unrealistic data or assumptions of behavior. This research proposes an information theoretic methodology to discover such complex network structures and dynamics while overcoming the difficulties historically associated with their study. …

Simulation Of Aircraft Sortie Generation Under An Autonomic Logistics System, Gunduz Bingol

Theses and Dissertations

Parallel to the developments in diagnostic and prognostic technology, autonomic logistics systems (ALS) have been a potential improvement for the aircraft sortie generation process. Currently, Lockheed Martin and the Joint Program Office are developing a new autonomic logistics system for the multibillion F-35 Lightning Joint Strike Fighter project, which is named the Autonomic Logistics Information System (ALIS). Generally, researchers make an analogy between the ALS and the human bodys autonomic nervous system since both of them monitor, control, and adjust autonomic responses to external stimuli. Based on this perspective, ALS aims to switch the Air Force logistics mentality from a …

Improvements To Micro-Contact Performance And Reliability, Tod V. Laurvick

Theses and Dissertations

Microelectromechanical Systems (MEMS) based devices, and specifically microswitches, continue to offer many advantages over competing technologies. To realize the benefits of micro-switches, improvements must be made to address performance and reliability shortfalls which have long been an issue with this application. To improve the performance of these devices, the micro-contacts used in this technology must be understood to allow for design improvements, and offer a means for testing to validate this technology and determine when such improvements are ready for operational environments. To build devices which are more robust and capable of continued operation after billions of cycles requires that …

Passively Estimating Index Of Refraction For Specular Reflectors Using Polarimetric Hyperspectral Imaging, Jacob A. Martin

Theses and Dissertations

As off-nadir viewing platforms becoming increasingly prevalent in remote sensing, material classification and ID techniques robust to changing viewing geometries must be developed. Traditionally, either reflectivity or emissivity are used for classification, but these quantities vary with viewing angle. Instead, estimating index of refraction may be advantageous as it is invariant with respect to viewing geometry. This work focuses on estimating index of refraction from LWIR (875-1250 wavenumbers) polarimetric hyperspectral radiance measurements.

Dual Role Of Sb Ions As Electron Traps And Hole Traps In Photorefractive Sn2P2S6 Crystals, Brant E. Kananen, Eric M. Golden, Sergey A. Basun, D. R. Evans, A. A. Grabar, I. M. Stoika, John W. Mcclory, Nancy C. Giles, Larry E. Halliburton

Faculty Publications

Doping photorefractive single crystals of Sn₂P₂S₆ with antimony introduces both electron and hole traps. In as-grown crystals, Sb³⁺ (5s²) ions replace Sn²⁺ ions. These Sb³⁺ ions are either isolated (with no nearby perturbing defects) or they have a charge-compensating Sn²⁺ vacancy at a nearest-neighbor Sn site. When illuminated with 633 nm laser light, isolated Sb³⁺ ions trap electrons and become Sb²⁺ (5s²5p¹) ions. In contrast, Sb³⁺ ions with an adjacent Sn vacancy trap holes during illumination. The hole is primarily …

Reflective Inverse Diffusion, Kenneth W. Burgi, Jessica Ullom, Michael A. Marciniak, Mark E. Oxley

Faculty Publications

Phase front modulation was previously used to refocus light after transmission through scattering media. This process has been adapted here to work in reflection. A liquid crystal spatial light modulator is used to conjugate the phase scattering properties of diffuse reflectors to produce a converging phase front just after reflection. The resultant focused spot had intensity enhancement values between 13 and 122 depending on the type of reflector. The intensity enhancement of more specular materials was greater in the specular region, while diffuse reflector materials achieved a greater enhancement in non-specular regions, facilitating non-mechanical steering of the focused spot. Scalar …

Using Timing-Based Side Channels For Anomaly Detection In Industrial Control Systems, Stephen Dunlap, Jonathan W. Butts, Juan L. Lopez Jr., Mason J. Rice, Barry E. Mullins

Faculty Publications

The critical infrastructure, which includes the electric power grid, railroads and water treatment facilities, is dependent on the proper operation of industrial control systems. However, malware such as Stuxnet has demonstrated the ability to alter industrial control system parameters to create physical effects. Of particular concern is malware that targets embedded devices that monitor and control system functionality, while masking the actions from plant operators and security analysts. Indeed, system security relies on guarantees that the assurance of these devices can be maintained throughout their lifetimes. This paper presents a novel approach that uses timing-based side channel analysis to establish …

High Pressure Line Shapes Of The Rb D1 And D2 Lines For 4He And 3He Collisions, Wooddy S. Miller, Christopher A. Rice, Gordon D. Hager, Matthew D. Rotondaro, Hamid Berriche, Glen P. Perram

Faculty Publications

Line shapes for the Rb D₁ (5²S_1/2 ↔ 5²P_1/2) and D₂ (5²S_1/2 ↔ 5²P_3/2) transitions with ⁴He and ³He collisions at pressures of 500–15,000 Torr and temperatures of 333–533 K have been experimentally observed and compared to predictions from the Anderson–Talman theory. The ground X²Σ⁺_1/2 and excited A²Π_1/2, A²Π_3/2, and B²Σ⁺_1/2 potential energy surfaces required for the line shape predictions have been calculated using a one-electron …

A Method For Revealing And Addressing Security Vulnerabilities In Cyber-Physical Systems By Modeling Malicious Agent Interactions With Formal Verification, Dean C. Wardell, Robert F. Mills, Gilbert L. Peterson, Mark E. Oxley

Faculty Publications

Several cyber-attacks on the cyber-physical systems (CPS) that monitor and control critical infrastructure were publically announced over the last few years. Almost without exception, the proposed security solutions focus on preventing unauthorized access to the industrial control systems (ICS) at various levels – the defense in depth approach. While useful, it does not address the problem of making the systems more capable of responding to the malicious actions of an attacker once they have gained access to the system. The first step in making an ICS more resilient to an attacker is identifying the cyber security vulnerabilities the attacker can …

Sn Vacancies In Photorefractive Sn2P2S6 Crystals: An Electron Paramagnetic Resonance Study Of An Optically Active Hole Trap, Eric M. Golden, Sergey A. Basun, D. R. Evans, A. A. Grabar, I. M. Stoika, Nancy C. Giles, Larry E. Halliburton

Faculty Publications

Electron paramagnetic resonance (EPR) is used to identify the singly ionized charge state of the Sn vacancy (V⁻_Sn) in single crystals of Sn₂P₂S₆ (often referred to as SPS). These vacancies, acting as a hole trap, are expected to be important participants in the photorefractive effect observed in undoped SPS crystals. In as-grown crystals, the Sn vacancies are doubly ionized (V²⁻_Sn) with no unpaired spins. They are then converted to a stable EPR-active state when an electron is removed (i.e., a hole is trapped) during an illumination below 100 K …

Effect Of Stress Ratio On Fatigue Crack Growth Rate At Notched Hole In 7075-T6 Aluminum Alloy Under Biaxial Fatigue, Reja Alshahrani

Theses and Dissertations

This research investigates the behavior of fatigue crack growth rate in both laboratory air and saltwater (3.5% NaCl) environments for notched cruciform specimen made from 7075-T6 aluminum alloy sheet at different stress ratios. With biaxility ratio of 1, and frequency of applied load of 10 Hz, the crack growth behavior was investigated under in-plane biaxial tension-tension fatigue with 0.1, 0.5, 0.7 stress ratios and then compared them to study the effect of stress ratio on the crack growth rate. Finite Element Analysis (FEA) was used to calculate cyclic variation of stress intensity factors (delta K) at the crack tips. The …

Conceptual Architecture To Measure The Effects Of Subauroral Polarization Streams On Radar Operations, Shayla K. Redmond

Theses and Dissertations

This thesis provides the initial conceptual development of taking into account subauroral polarization streams when preparing for a radar operation. The DoDAF views created to portray the architecture consisted of operational, capabilities, data and information, and finally system views to ensure consistency and realistic outcomes. OV-2 was the significant view because it set the baseline for required actions necessary for the proposed results the Flow Integration of Ionospheric Activity and Radar Evaluation (FIIARE) system would produce. FIIARE is a computer based system concept that performs consolidations and produce predictions using algorithms from the International Reference Ionosphere (IRI). The data portrayed …

Cavity Geometric Features And Entrainment Characterization Resulting From A Ballistically Induced Hydrodynamic Ram Event, Andrew J. Lingenfelter

Theses and Dissertations

Hydrodynamic Ram can cause damage to industrial and aircraft systems. The resulting transient spray increases the probability of fire. To better understand the driving mechanisms behind transient spray, internal, and external measurements of the cavity geometry, and entrained flow field were accomplished. Research determined cavity contraction and separation are pre-cursors to the initiation of the transient spray phases. The entrained flow measurement required development of a new and novel technique using a continuous wave laser and atomized water particles. The peak mass flow correlated well with cavity geometric features, such as cavity contraction. Using the mass flow, cavity diameter at …

A Temporal Framework For Hypergame Analysis Of Cyber Physical Systems In Contested Environments, Nicholas S. Kovach

Theses and Dissertations

Game theory is used to model conflicts between one or more players over resources. It offers players a way to reason, allowing rationale for selecting strategies that avoid the worst outcome. Game theory lacks the ability to incorporate advantages one player may have over another player. A meta-game, known as a hypergame, occurs when one player does not know or fully understand all the strategies of a game. Hypergame theory builds upon the utility of game theory by allowing a player to outmaneuver an opponent, thus obtaining a more preferred outcome with higher utility. Recent work in hypergame theory has …

Optimal Control Of An Uninhabited Loyal Wingman, Clay J. Humphreys

Theses and Dissertations

As researchers strive to achieve autonomy in systems, many believe the goal is not that machines should attain full autonomy, but rather to obtain the right level of autonomy for an appropriate man-machine interaction. A common phrase for this interaction is manned-unmanned teaming (MUM-T), a subset of which, for unmanned aerial vehicles, is the concept of the loyal wingman. This work demonstrates the use of optimal control and stochastic estimation techniques as an autonomous near real-time dynamic route planner for the DoD concept of the loyal wingman. First, the optimal control problem is formulated for a static threat environment and …

A Statistical Approach To Characterize And Detect Degradation Within The Barabasi-Albert Network, Mohd-Fairul Mohd-Zaid

Theses and Dissertations

Social Network Analysis (SNA) is widely used by the intelligence community when analyzing the relationships between individuals within groups of interest. Hence, any tools that can be quantitatively shown to help improve the analyses are advantageous for the intelligence community. To date, there have been no methods developed to characterize a real world network as a Barabasi-Albert network which is a type of network with properties contained in many real-world networks. In this research, two newly developed statistical tests using the degree distribution and the L-moments of the degree distribution are proposed with application to classifying networks and detecting degradation …