Physical Sciences and Mathematics Commons^™

Three-Dimensional Imaging Of Cold Atoms In A Magneto-Optical Trap With A Light Field Microscope, Gordon E. Lott

Theses and Dissertations

Imaging of trapped atoms in three dimensions utilizing a light field microscope is demonstrated in this work. Such a system is of interest in the development of atom interferometer accelerometers in dynamic systems where strictly defined focal planes may be impractical. A light field microscope was constructed utilizing a Lytro® Development Kit micro-lens array and sensor. It was used to image fluorescing rubidium atoms in a magneto-optical trap. The three-dimensional (3D) volume of the atoms is reconstructed using a modeled point spread function (PSF), taking into consideration the low magnification (1.25) of the system which changed typical assumptions in the …

Analysis Of Ar(1s5) Metastable Populations In High Pressure Argon-Helium Gas Discharges, Daniel J. Emmons Ii

Theses and Dissertations

Simulations of an argon-helium plasma are performed for two high pressure discharge scenarios to find a uniform, large-volume plasma with Ar(1s5) metastable densities on the order of 10¹³ cm^-3 for use as the ground state in an optically pumped rare gas laser. An analysis of a pulsed direct current discharge is performed for a 7% argon in helium mixture at a pressure of 270 Torr using both zero and one-dimensional models. Kinetics of species relevant to the operation of an optically pumped rare gas laser are analyzed throughout the pulse duration to identify key reaction pathways. Simulations are …

A Tree Locality-Sensitive Hash For Secure Software Testing, Camdon J. Cady

Theses and Dissertations

Bugs in software that make it through testing can cost tens of millions of dollars each year, and in some cases can even result in the loss of human life. In order to eliminate bugs, developers may use symbolic execution to search through possible program states looking for anomalous states. Most of the computational effort to search through these states is spent solving path constraints in order to determine the feasibility of entering each state. State merging can make this search more efficient by combining program states, allowing multiple execution paths to be analyzed at the same time. However, a …

Biologically Inspired Network (Bionet) Authentication Using Logical And Pathological Rf-Dna Credential Pairs, Tyrone A.L. Lewis Sr.

Theses and Dissertations

The command and control (C2) of shared space resources are vulnerable to logical credential forgery and impersonation attacks among standardized and interoperable wireless radio frequency (RF) networks. Threats could come from trusted operators (insiders) or from external sources (outsiders). An attacker may gain unauthorized network access and illegally cross into C2 boundaries when conventional network authentication fails. This research proposes an integrated trust management system that uses both application-layer and physical-layer trust markers to authenticate users and their communication sources. In essence, the results from physical-layer RF-DNA fingerprinting techniques are used to improve application-level trust schemes based on command patterns, …

Automated Software Testing In The Dod: Current Practices And Opportunities For Improvement, Darryl K. Ahner, James Wisnowski, James R. Simpson

Faculty Publications

The concept of automating the testing of software-intensive systems has been around for decades, but the practice of automating testing is scarce in many industries, especially in the government defense sector. A one-year project initiated by the Office of the Secretary of Defense (OSD), Scientific Test and Analysis Techniques Center of Excellence (STAT COE) and sponsored by Navy OPNAV N94 set out to:

• study the degree to which the Department of Defense (DoD) has adopted automated software testing (AST);

• share the best software practices used by industry; and

• develop and distribute an AST implementation guide intended for program management and …

  ---

  Go to article

Synthesis Of Non-Uniformly Correlated Partially Coherent Sources Using A Deformable Mirror, Milo W. Hyde Iv, Santasri Bose-Pillai, Ryan A. Wood

Faculty Publications

The near real-time synthesis of a non-uniformly correlated partially coherent source using a low-actuator-count deformable mirror is demonstrated. The statistical optics theory underpinning the synthesis method is reviewed. The experimental results of a non-uniformly correlated source are presented and compared to theoretical predictions. A discussion on how deformable mirror characteristics such as actuator count and pitch affect source generation is also included.

Stochastic Quasilinear Evolution Equations In Umd Banach Spaces, Manil T. Mohan, Sivaguru S. Sritharan

Faculty Publications

In this work we prove the existence and uniqueness up to a stopping time for the stochastic counterpart of Tosio Kato's quasilinear evolutions in UMD Banach spaces. These class of evolutions are known to cover a large class of physically important nonlinear partial differential equations. Existence of a unique maximal solution as well as an estimate on the probability of positivity of stopping time is obtained. An example of stochastic Euler and Navier–Stokes equation is also given as an application of abstract theory to concrete models.

Luminescence In Lithium Borates, Brant E. Kananen

Theses and Dissertations

Spectrometry methods are used to identify and characterize point defects in single crystals of lithium tetraborate (Li₂B₄O₇) and lithium triborate (LiB₃O₅) doped with silver or copper, and explore the role of these point defects in luminescence. New defects are identified in Ag-doped including: lithium vacancy substitutional-silver-ion defect-pairs (hole trap); isolated lithium vacancies (hole trap); isolated oxygen vacancies (electron trap); interstitial-silver-ion substitutional-silver-ion defect pairs (electron trap); isolated interstitial silver ions (electron trap); and interstitial-silver-ion lithium-vacancy defect pairs (electron trap). Defect models are proposed, and adjustments made to defect models known defects. …

A Brief Introduction To Equi-Chordal And Equi-Isoclinic Tight Fusion Frames, Matthew C. Fickus, John Jasper, Dustin G. Mixon, Cody E. Watson

Faculty Publications

Equi-chordal and equi-isoclinic tight fusion frames (ECTFFs and EITFFs) are both types of optimal packings of subspaces in Euclidean spaces. In the special case where these subspaces are one-dimensional, ECTFFs and EITFFs both correspond to types of optimal packings of lines known as equiangular tight frames. In this brief note, we review some of the fundamental ideas and results concerning ECTFFs and EITFFs.

Fresnel Spatial Filtering Of Quasihomogeneous Sources For Wave Optics Simulations, Milo W. Hyde Iv, Santasri Bose-Pillai

Faculty Publications

High-spatial-frequency optical fields or sources are often encountered when simulating directed energy, active imaging, or remote sensing systems and scenarios. These spatially broadband fields are a challenge in wave optics simulations because the sampling required to represent and then propagate these fields without aliasing is often impractical. To address this, two spatial filtering techniques are presented. The first, called Fresnel spatial filtering, finds a spatially band-limited source that, after propagation, produces the exact observation plane field as the broadband source over a user-specified region of interest. The second, called statistical or quasihomogeneous spatial filtering, finds a spatially band-limited source that, …

Anomalydetection: Implementation Of Augmented Network Log Anomaly Detection Procedures, Robert J. Gutierrez, Bradley C. Boehmke, Kenneth W. Bauer, Cade M. Saie, Trevor J. Bihl

Faculty Publications

As the number of cyber-attacks continues to grow on a daily basis, so does the delay in threat detection. For instance, in 2015, the Office of Personnel Management discovered that approximately 21.5 million individual records of Federal employees and contractors had been stolen. On average, the time between an attack and its discovery is more than 200 days. In the case of the OPM breach, the attack had been going on for almost a year. Currently, cyber analysts inspect numerous potential incidents on a daily basis, but have neither the time nor the resources available to perform such a task. …

On-Chip, High-Sensitivity Temperature Sensors Based On Dye-Doped Solid-State Polymer Microring Lasers, Lei Wan, Hengky Chandrahalim, Cong Chen, Qiushu Chen, Ting Mei, Yuji Oki, Naoya Nishimura, Lingjie Jay Guo, Xudong Fan

Faculty Publications

We developed a chip-scale temperature sensor with a high sensitivity of 228.6 pm/°C based on a rhodamine 6G (R6G)-doped SU-8 whispering-gallery mode microring laser. The optical mode was largely distributed in a polymer core layer with a 30 μm height that provided detection sensitivity, and the chemically robust fused-silica microring resonator host platform guaranteed its versatility for investigating different functional polymer materials with different refractive indices. As a proof of concept, a dye-doped hyperbranched polymer (TZ-001) microring laser-based temperature sensor was simultaneously developed on the same host wafer and characterized using a free-space optics measurement setup. Compared to TZ-001, the …

Electron Paramagnetic Resonance Study Of Neutral Mg Acceptors In Β-Ga2O3 Crystals, Brant E. Kananen [*], Larry E. Halliburton, Elizabeth M. Scherrer [*], K. T. Stevens, G. K. Foundos, K. B. Chang, Nancy C. Giles

Faculty Publications

Electron paramagnetic resonance (EPR) is used to directly observe and characterize neutral Mg acceptors (Mg⁰_Ga) in a β-Ga₂O₃ crystal. These acceptors, best considered as small polarons, are produced when the Mg-doped crystal is irradiated at or near 77 K with x rays. During the irradiation, neutral acceptors are formed when holes are trapped at singly ionized Mg acceptors (Mg−Ga). Unintentionally present Fe³⁺ (3d⁵) and Cr³⁺ (3d³) transition-metal ions serve as the corresponding electron traps. The hole is localized in a nonbonding p orbital on a threefold-coordinated oxygen ion …

Estimating Index Of Refraction For Specular Reflectors Using Passive Polarimetric Hyperspectral Radiance Measurements, Jacob A. Martin, Kevin C. Gross

Faculty Publications

Results of a method of estimating index of refraction from passive, polarimetric hyperspectral imaging radiance measurements are presented. As off-nadir viewing hyperspectral imaging platforms gain prominence, estimating index of refraction, which is invariant to viewing angle, may prove advantageous to estimating the emissivity, which is not. Results show that index of refraction can be retrieved to within 8% rms error for fused silica and sapphire glass targets, while simultaneously estimating object temperature. The accuracy and self-consistency of this technique for estimating index of refraction are shown to compare favorably to the maximum smoothness temperature–emissivity separation algorithm. Additionally, the results show …

Real-Time Camera Tracking System Using Optical Flow Feature Points, Daniel D. Doyle, Alan L. Jennings, Jonathan T. Black

AFIT Patents

A new apparatus and method for tracking a moving object with a moving camera provides a real-time, narrow field-of-view, high resolution and on target image by combining commanded motion with an optical flow algorithm for deriving motion and classifying background. Commanded motion means that movement of the pan, tilt and zoom (PTZ) unit is “commanded” by a computer, instead of being observed by the camera, so that the pan, tilt and zoom parameters are known, as opposed to having to be determined, significantly reducing the computational requirements for tracking a moving object. The present invention provides a single camera pan …

In-Beam Γ-Ray Spectroscopy Studies Of Medium-Spin States In The Odd-Odd Nucleus 186Re, David A. Matters, F. G. Kondev, N. Aoi, Y. Ayyad, A. P. Byrne, M. P. Carpenter, J. Carroll, C. J. Chiara, P. M. Davidson, G. D. Dracoulis, Y. D. Fang, C. R. Hoffmann, R. O. Hughes, E. Ideguchi, R. V. F. Janssens, S. Kanaya, B. P. Kay, T. Kibedi, G. J. Lane, T. Lauritsen, John W. Mcclory, P. Nieminen, S. Noji, A. Odahara, H. J. Ong, A. E. Stuchbery, D. T. Tran, H. Watanabe, A. N. Wilson, Y. Yamamoto, S. Zhu

Faculty Publications

Excited states in ¹⁸⁶Re with spins up to J=12ℏ were investigated in two separate experiments using 186W(d,2n) reactions at beam energies of 12.5 and 14.5 MeV. Two- and threefold γ-ray coincidence data were collected using the CAESAR and CAGRA spectrometers, respectively, each composed of Compton-suppressed high-purity germanium detectors. Analysis of the data revealed rotational bands built on several two-quasiparticle intrinsic states, including a long-lived K^π=(8⁺) isomer. Configuration assignments were supported by an analysis of in-band properties, such as |gK−gR| values. The excitation energies of the observed intrinsic states were compared with results from multi-quasiparticle blocking …

Improved Atmospheric Characterization For Hyperspectral Exploitation, Nathan P. Wurst

Theses and Dissertations

Airborne hyperspectral imaging (HSI) in the LWIR has shown utility in material detection and identification. This research seeks to determine the most effective methods to perform model-based atmospheric compensation of LWIR HSI data by comparing results obtained from different atmospheric profiles. The standard model for mid-latitude summer (MLS) and radiosonde data are compared to the National Operational Model Archive and Distribution System (NOMADS) numerical weather predictions and the Extreme and Percentile Environmental Reference Tables (ExPERT). The two latter atmospheric profiles are generated using the Laser Environmental Effects Definition and Reference (LEEDR) software. MLS has been a standard starting point for …

Measuring The Reflection Matrix Of A Rough Surface, Kenneth W. Burgi, Michael A. Marciniak, Mark E. Oxley, Stephen E. Nauyoks

Faculty Publications

Phase modulation methods for imaging around corners with reflectively scattered light required illumination of the occluded scene with a light source either in the scene or with direct line of sight to the scene. The RM (reflection matrix) allows control and refocusing of light after reflection, which could provide a means of illuminating an occluded scene without access or line of sight. Two optical arrangements, one focal-plane, the other an imaging system, were used to measure the RM of five different rough-surface reflectors. Intensity enhancement values of up to 24 were achieved. Surface roughness, correlation length, and slope were examined …

Stereoscopic 3-D Presentation For Air Traffic Control Digital Radar Displays, Jason G. Russi, Brent T. Langhals, Michael E. Miller, Eric L. Heft

AFIT Patents

An apparatus and method of presenting air traffic data to an air traffic controller are provided. Air traffic data including a two dimensional spatial location and altitude for a plurality of aircraft is received. A disparity value is determined based on the altitude for each aircraft of the plurality of aircraft. Left and right eye images are generated of the plurality of aircraft where at least one of the left and right eye images is based on the determined disparity value. The left and right eye images are simultaneously displayed to the air traffic controller on a display. The simultaneously …

Gallium Vacancies In Β-Ga2O3 Crystals, Brant E. Kananen [*], Larry E. Halliburton, K. T. Stevens, G. K. Foundos

Faculty Publications

The gallium vacancy, an intrinsic acceptor, is identified in β-Ga₂O₃ using electron paramagnetic resonance (EPR). Spectra from doubly ionized (V²⁻_Ga) and singly ionized (V⁻_Ga) gallium vacancies are observed at room temperature, without photoexcitation, after an irradiation with high-energy neutrons. The V²⁻_Ga centers (with S = 1/2) have a slight angular variation due to a small anisotropy in the g matrix (principal values are 2.0034, 2.0097, and 2.0322). The V²⁻_Ga centers also exhibit a resolved hyperfine structure due to equal and nearly isotropic interactions with the …

Analysis Of Beam Deflection Measurements In The Presence Of Linear Absorption, Manuel R. Ferdinandus, Jennifer Reed, Kent L. Averett, F. Kenneth Hopkins, Augustine Urbas

Faculty Publications

We develop a series of analytical approximations allowing for rapid extraction of the nonlinear parameters from beam deflection measurements. We then apply these approximations to the analysis of cadmium silicon phosphide and compare the results against previously published parameter extraction methods and find good agreement for typical experimental conditions.

Kinetics Of High Pressure Argon-Helium Pulsed Gas Discharge, Daniel J. Emmons, David E. Weeks

Faculty Publications

Simulations of a pulsed direct current discharge are performed for a 7% argon in helium mixture at a pressure of 270 Torr using both zero- and one-dimensional models. Kinetics of species relevant to the operation of an optically pumped rare-gas laser are analyzed throughout the pulse duration to identify key reaction pathways. Time dependent densities, electron temperatures, current densities, and reduced electric fields in the positive column are analyzed over a single 20 μs pulse, showing temporal agreement between the two models. Through the use of a robust reaction rate package, radiation trapping is determined to play a key role …

Periodic Traveling Interfacial Hydroelastic Waves With Or Without Mass, Benjamin F. Akers, David M. Ambrose, David W. Sulon

Faculty Publications

We study the motion of an interface between two irrotational, incompressible fluids, with elastic bending forces present; this is the hydroelastic wave problem. We prove a global bifurcation theorem for the existence of families of spatially periodic traveling waves on infinite depth. Our traveling wave formulation uses a parameterized curve, in which the waves are able to have multi-valued height. This formulation and the presence of the elastic bending terms allows for the application of an abstract global bifurcation theorem of "identity plus compact" type. We furthermore perform numerical computations of these families of traveling waves, finding that, depending on …

Increasing Cyber Resiliency Of Industrial Control Systems, Andrew J. Chaves

Theses and Dissertations

Industrial control systems (ICS) are designed to be resilient, capable of recovering from process faults and failures with limited impact to operations. Current ICS resiliency strategies use redundant PLCs. However, these redundant PLCs, being of similar make and model, can be exploited by the same cyber attack, defeating the ICS's resiliency strategy. This research proposes a resiliency strategy for ICS that employs an active defense technique to remove the cyber common cause failure. The resiliency of the active defense strategy is compared to traditional ICS resiliency by implementing both strategies in a semi-simulated wastewater treatment plant aeration basin that experiences …

Adsorption Of Perfluorinated Compounds From Post-Emergency Response Wastewater, Christopher T. Schmidt

Theses and Dissertations

This research investigated the efficacy of granular activated carbon (GAC) as a method to treat water impacted with aqueous film forming foam (AFFF) after a firefighting response. Bench-top experiments were conducted and compared to field scale adsorber performance removing mg/L concentrations of PFAS in water contaminated with Military Specification AFFF. Batch tests compared four adsorbents, and determined Calgon F600 GAC and Rembind Plus mixed carbon media had the greatest perfluorooctane sulfonate (PFOS) capacities. Additional batch isotherm experiments using AFFF and higher PFOS concentrations (mg/L) indicated larger amounts of GAC are required (>30mg/L) for effective removal. Full-scale testing simulated an …

Multi-Plc Exercise Environments For Training Ics First Responders, Joseph K. Daoud

Theses and Dissertations

When systems are targeted by cyber attacks, cyber first responders must be able to react effectively, especially when dealing with critical infrastructure. Training for cyber first responders is lacking and most existing exercise platforms are expensive, inaccessible or ineffective. This paper presents a mobile training platform which incorporates a variety of programmable logic controllers into a single system which facilitates the development of the unique skills required of cyber first responders operating in the realm of industrial control systems. The platform is modeled after a jail in the northeastern United States and was developed to maximize realism. Example training scenarios …

Autoprov: An Automated File Provenance Collection Tool, Ryan A. Good

Theses and Dissertations

A file's provenance is a detailing of its origins and activities. There are tools available that are useful in maintaining the provenance of a file. Unfortunately for digital forensics, these tools require prior installation on the computer of interest while provenance generating events happen. The presented tool addresses this by reconstructing a file's provenance from several temporal artifacts. It identifies relevant temporal and user correlations between these artifacts, and presents them to the user. A variety of predefined use cases and real world data are tested against to demonstrate that this software allows examiners to draw useful conclusions about the …

A Computational Study: The Effect Of Hypersonic Plasma Sheaths On Radar Cross Section For Over The Horizon Radar, Zachary W. Hoeffner

Theses and Dissertations

In this study radar cross sections were calculated for an axial symmetric 6-degree half angle blunted cone with a nose radius of 2.5 cm and length of 3.5 m including and excluding the effects of an atmospheric hypersonic plasma sheath for altitudes of 40 km, 60 km and 80 km and speeds of 5 km/s, 6 km/s and 7 km/s. LAURA, was used to determine the plasma characteristics for the hypersonic flight conditions using a 11-species 2-temperature chemical model. Runs were accomplished first with a super-catalytic surface boundary condition without a turbulence model and then for some cases with an …

Modeling The White Sands Missile Range Fast Burst Reactor Using A Discrete Ordinates Code, Pentran, Taylor R. Schulmeister

Theses and Dissertations

The goal of this research was to develop and characterize a deterministic model of a fast burst reactor (FBR) using a discrete ordinates neutral particle transport code, PENTRAN. The White Sands Missile Range FBR design was chosen for this research because this FBR is important to the DoD due to its short duration, high energy neutron flux which is representative of the neutron flux output created by a nuclear weapon. One, two, and three dimensional PENTRAN models of the FBR were developed and neutron transport based eigenvalue calculations were performed. These eigenvalue calculations were conducted using two different set of …

The Air Force Fitness Test: Creating New Fitness Assessment Charts Using Waist To Height Ratios, John R. Griffith

Theses and Dissertations

The Air Force currently uses AFI 36-2905 for fitness standards and evaluation, but no study to our knowledge has evaluated these standards using large databases. Using a 5.38 million record database from the Air Force Fitness Management System, we evaluated how the abdominal circumference, body mass index (BMI), waist to height ratio (WtHR), and height to weight ratio correlated to fitness as assessed by the 1.5 mile aerobic run in the Air Force Fitness Test. Whether individually or adjusting for age group and gender, WtHR performed better that the rest with an average rank score of 1.1 with a relative …