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Air Force Institute of Technology

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Full-Text Articles in Physical Sciences and Mathematics

Pump Diode Characterization For An Unstable Diode-Pumped Alkali Laser Resonator, Chad T. Taguba Mar 2013

Pump Diode Characterization For An Unstable Diode-Pumped Alkali Laser Resonator, Chad T. Taguba

Theses and Dissertations

Measurements of wavelength tunability, spectral linewidth, minimum spot size, and M2 were made for a rubidium diode-pumped alkali laser (DPAL) containing a volume Bragg grating (VBG) for resonator characterization. The output wavelength of the pump diode was measured as a function of volume Bragg grating temperature. A linear relationship was observed that corresponded to an output wavelength range of 780.08 nm 0.01 nm to 780.49 nm 0.01 nm with a tuning rate of 6.1 pm/ C for a diode chassis temperature of 37 C. Rubidium D1 fuorescence spectra were recorded as the diode wavelength was scanned across its full range …


Multipactor Discharge In High Power Microwave Systems: Analyzing Effects And Mitigation Through Simulation In Icepic, Robert L. Lloyd Mar 2013

Multipactor Discharge In High Power Microwave Systems: Analyzing Effects And Mitigation Through Simulation In Icepic, Robert L. Lloyd

Theses and Dissertations

Single surface multipactor in high power microwave systems was investigated computationally and analytically. The research focused upon understanding the cause and parametric dependence of the multipactor process leading to suggested methods of mitigation. System damage due to reaction was also assessed. All simulations were performed using the PIC code developed by AFRL, known as ICEPIC. In recreating the susceptibility curves that define regions of multipactor growth and decay, a discrepancy was found between previous published results and those observed in the current simulation. This was attributed to previous simulations not accounting for the magnetic component in the electromagnetic radiation incident …


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 …


Distributional Monte Carlo Methods For The Boltzmann Equation, Christopher R. Schrock Mar 2013

Distributional Monte Carlo Methods For The Boltzmann Equation, Christopher R. Schrock

Theses and Dissertations

Stochastic particle methods (SPMs) for the Boltzmann equation, such as the Direct Simulation Monte Carlo (DSMC) technique, have gained popularity for the prediction of flows in which the assumptions behind the continuum equations of fluid mechanics break down; however, there are still a number of issues that make SPMs computationally challenging for practical use. In traditional SPMs, simulated particles may possess only a single velocity vector, even though they may represent an extremely large collection of actual particles. This limits the method to converge only in law to the Boltzmann solution. This document details the development of new SPMs that …


Role Of Excited State Photoionization In The 852.1 Nm Cs Laser Pumped By Cs-Ar Photoassociation, J. D. Hewitt, T. J. Houlahan Jr., Jeffrey E. Gallagher, D. L. Carroll, A. D. Palla, J. T. Verdeyen, Glen P. Perram, J. G. Eden Mar 2013

Role Of Excited State Photoionization In The 852.1 Nm Cs Laser Pumped By Cs-Ar Photoassociation, J. D. Hewitt, T. J. Houlahan Jr., Jeffrey E. Gallagher, D. L. Carroll, A. D. Palla, J. T. Verdeyen, Glen P. Perram, J. G. Eden

Faculty Publications

Photoionization of Cs (6p2P3/2) atoms during the operation of a Cs D2 line (852.1 nm: 6p2P3/2→6s2S1/2) laser, pumped by free→free transitions of thermal Cs-Ar ground state pairs, has been investigated experimentally and computationally. Photoexcitation of Cs vapor/Ar mixtures through the blue satellite of the D2 transition (peaking at 836.7 nm) selectively populates the 2P3/2 upper laser level by the dissociation of the CsAr excited complex. Comparison of laser output energy data, for instantaneous pump powers up to 3 MW, with the …


Insertion Of Lithium Ions Into Tio2 (Rutile) Crystals: An Electron Paramagnetic Resonance Study Of The Li-Associated Ti3+ Small Polaron, A. T. Brant, Nancy C. Giles, Larry E. Halliburton Feb 2013

Insertion Of Lithium Ions Into Tio2 (Rutile) Crystals: An Electron Paramagnetic Resonance Study Of The Li-Associated Ti3+ Small Polaron, A. T. Brant, Nancy C. Giles, Larry E. Halliburton

Faculty Publications

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) are used to identify a Ti3+-Li+ complex in TiO2 crystals having the rutile structure. This defect consists of an interstitial Li+ ion adjacent to a substitutional Ti3+ ion (the unpaired electron on the Ti3+ ion provides charge compensation for the Li+ ion). The neutral Ti3+-Li+ complex is best described as a donor-bound small polaron and is similar in structure to the recently reported neutral fluorine and hydrogen donors in TiO2 (rutile). Lithium ions are diffused into the crystals at …


Insider Threat Detection Using Virtual Machine Introspection, M. Crawford, Gilbert L. Peterson, Robert F. Mills, Michael R. Grimaila Jan 2013

Insider Threat Detection Using Virtual Machine Introspection, M. Crawford, Gilbert L. Peterson, Robert F. Mills, Michael R. Grimaila

Faculty Publications

This paper presents a methodology for signaling potentially malicious insider behavior using virtual machine introspection (VMI). VMI provides a novel means to detect potential malicious insiders because the introspection tools remain transparent and inaccessible to the guest and are extremely difficult to subvert. This research develops a four step methodology for development and validation of malicious insider threat alerting using VMI. A malicious attacker taxonomy is used to decompose each scenario to aid identification of observables for monitoring for potentially malicious actions. The effectiveness of the identified observables is validated using two data sets. Results of the research show the …


The Road To Deterministic Matrices With The Restricted Isometry Property, Afonso S. Bandeira, Matthew C. Fickus, Dustin G. Mixon, Percy Wong Jan 2013

The Road To Deterministic Matrices With The Restricted Isometry Property, Afonso S. Bandeira, Matthew C. Fickus, Dustin G. Mixon, Percy Wong

Faculty Publications

The restricted isometry property (RIP) is a well-known matrix condition that provides state-of-the-art reconstruction guarantees for compressed sensing. While random matrices are known to satisfy this property with high probability, deterministic constructions have found less success. In this paper, we consider various techniques for demonstrating RIP deterministically, some popular and some novel, and we evaluate their performance. In evaluating some techniques, we apply random matrix theory and inadvertently find a simple alternative proof that certain random matrices are RIP. Later, we propose a particular class of matrices as candidates for being RIP, namely, equiangular tight frames (ETFs). Using the known …


Large-Scale Cooperative Task Distribution On Peer-To-Peer Networks, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins Jan 2013

Large-Scale Cooperative Task Distribution On Peer-To-Peer Networks, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins

Faculty Publications

Large-scale systems are part of a growing trend in distributed computing, and coordinating control of them is an increasing challenge. This paper presents a cooperative agent system that scales to one million or more nodes in which agents form coalitions to complete global task objectives. This approach uses the large-scale Command and Control (C2) capabilities of the Resource Clustered Chord (RC-Chord) Hierarchical Peer-to-Peer (HP2P) design. Tasks are submitted that require access to processing, data, or hardware resources, and a distributed agent search is performed to recruit agents to satisfy the distributed task. This approach differs from others by incorporating design …


Ensemble Forecasting Of Coronal Mass Ejections Using The Wsa-Enlil With Coned Model, D. Emmons, Ariel O. Acebal, A. Pulkkinen, A. Taktakishvili, Peter Macneice, D. Odstrcil Jan 2013

Ensemble Forecasting Of Coronal Mass Ejections Using The Wsa-Enlil With Coned Model, D. Emmons, Ariel O. Acebal, A. Pulkkinen, A. Taktakishvili, Peter Macneice, D. Odstrcil

Faculty Publications

The combination of the Wang‐Sheeley‐Arge (WSA) coronal model, ENLIL heliospherical model version 2.7, and CONED Model version 1.3 (WSA‐ENLIL with CONED Model) was employed to form ensemble forecasts for 15 halo coronal mass ejections (halo CMEs). The input parameter distributions were formed from 100 sets of CME cone parameters derived from the CONED Model. The CONED Model used image processing along with the bootstrap approach to automatically calculate cone parameter distributions from SOHO/LASCO imagery based on techniques described by Pulkkinen et al. (2010). The input parameter distributions were used as input to WSA‐ENLIL to calculate the temporal evolution of the …


Passive Ranging Using A Dispersive Spectrometer And Optical Filters, Jacob A. Martin Dec 2012

Passive Ranging Using A Dispersive Spectrometer And Optical Filters, Jacob A. Martin

Theses and Dissertations

Monocular passive ranging using atmospheric oxygen absorption has been demonstrated in the past using an FTS. These instruments are very sensitive to vibration making them di cult to use on an airborne platform. This work focuses on whether passive ranging can be done with instruments that are easier to deploy. Two potential instruments are tested and compared: a diffraction grating spectrometer and optical filters. A grating spectrometer was able to estimate range to within 5% for a static solid rocket motor ring at a distance of 910 m using the NIR absorption band of oxygen. Testing at shorter ranges produced …


Epr And Endor Studies Of Point Defects In Lithium Tetraborate Crystals, Douglas A. Buchanan Dec 2012

Epr And Endor Studies Of Point Defects In Lithium Tetraborate Crystals, Douglas A. Buchanan

Theses and Dissertations

Lithium tetraborate (Li2B4O7 or LTB) is a promising material for both radiation dosimetry and neutron detection applications. LTB crystals can be grown pure or doped with different impurities including transition-metal and rare-earth ions. Research in this dissertation focuses on undoped LTB crystals and LTB crystals doped with copper and silver. Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) are used to characterize point defects in the lithium tetraborate crystals. Thermoluminescence (TL), photoluminescence (PL), photoluminescence excitation (PLE), and optical absorption (OA) are also used. An intrinsic hole trap associated with lithium vacancies is characterized with EPR and ENDOR and its …


Parametrizing Finite Frames And Optimal Frame Completions, Miriam J. Poteet Dec 2012

Parametrizing Finite Frames And Optimal Frame Completions, Miriam J. Poteet

Theses and Dissertations

Frames are used in many signal processing applications. We consider the problem of constructing every frame whose frame operator has a given spectrum and whose vectors have prescribed lengths. For a given spectrum and set of lengths, we know when such a frame exists by the Schur-Horn Theorem; it exists if and only if its spectrum majorizes its squared lengths. We provide a more constructive proof of Horn's original result. This proof is based on a new method for constructing any and all frames whose frame operator has a prescribed spectrum and whose vectors have prescribed lengths. Constructing all such …


Emulation-Based Software Protection, William B. Kimball, Rusty O. Baldwin Oct 2012

Emulation-Based Software Protection, William B. Kimball, Rusty O. Baldwin

AFIT Patents

A method of emulation-based page granularity code signing comprising the steps of: copying guest operating system instructions and associated hash message authentication codes and/or digital signatures of each guest operating instruction from an untrusted guest operating system memory into a trusted host operating system memory; recomputing the hash message authentication codes using a secret key in the trusted host operating system memory; maintaining the secret key in the trusted host operating system memory and inaccessible by the untrusted guest operating system instructions; translating each guest operating system instruction that has a valid hash message authentication code to a set of …


Degenerate Parallel Conducting Layer And Conductivity Type Conversion Observed From P-Ge1 - YSnY (Y = 0.06%) Grown On N-Si Substrate, Mee-Yi Ryu, Yung Kee Yeo, M. Ahoujja, Thomas R. Harris, Richard T. Beeler, John Kouvetakis Sep 2012

Degenerate Parallel Conducting Layer And Conductivity Type Conversion Observed From P-Ge1 - YSnY (Y = 0.06%) Grown On N-Si Substrate, Mee-Yi Ryu, Yung Kee Yeo, M. Ahoujja, Thomas R. Harris, Richard T. Beeler, John Kouvetakis

Faculty Publications

Electrical properties of p-Ge1−ySny (y = 0.06%) grown on n-Si substrate were investigated through temperature-dependent Hall-effect measurements. It was found that there exists a degenerate parallel conducting layer in Ge1−ySny/Si and a second, deeper acceptor in addition to a shallow acceptor. This parallel conducting layer dominates the electrical properties of the Ge1−ySny layer below 50 K and also significantly affects those properties at higher temperatures. Additionally, a conductivity type conversion from p to n was observed around 370 K for this sample. A two-layer conducting model was used …


Utilizing Graphics Processing Units For Network Anomaly Detection, Jonathan D. Hersack Sep 2012

Utilizing Graphics Processing Units For Network Anomaly Detection, Jonathan D. Hersack

Theses and Dissertations

This research explores the benefits of using commonly-available graphics processing units (GPUs) to perform classification of network traffic using supervised machine learning algorithms. Two full factorial experiments are conducted using a NVIDIA GeForce GTX 280 graphics card. The goal of the first experiment is to create a baseline for the relative performance of the CPU and GPU implementations of artificial neural network (ANN) and support vector machine (SVM) detection methods under varying loads. The goal of the second experiment is to determine the optimal ensemble configuration for classifying processed packet payloads using the GPU anomaly detector. The GPU ANN achieves …


Effects Of Architecture On Information Leakage Of A Hardware Advanced Encryption Standard Implementation, Eric A. Koziel Sep 2012

Effects Of Architecture On Information Leakage Of A Hardware Advanced Encryption Standard Implementation, Eric A. Koziel

Theses and Dissertations

Side-channel analysis (SCA) is a threat to many modern cryptosystems. Many countermeasures exist, but are costly to implement and still do not provide complete protection against SCA. A plausible alternative is to design the cryptosystem using architectures that are known to leak little information about the cryptosystem's operations. This research uses several common primitive architectures for the Advanced Encryption Standard (AES) and assesses the susceptibility of the full AES system to side-channel attack for various primitive configurations. A combined encryption/decryption core is also evaluated to determine if variation of high-level architectures affects leakage characteristics. These different configurations are evaluated under …


Creating Network Attack Priority Lists By Analyzing Email Traffic Using Predefined Profiles, Eric J. Merrit Sep 2012

Creating Network Attack Priority Lists By Analyzing Email Traffic Using Predefined Profiles, Eric J. Merrit

Theses and Dissertations

Networks can be vast and complicated entities consisting of both servers and workstations that contain information sought by attackers. Searching for specific data in a large network can be a time consuming process. Vast amounts of data either passes through or is stored by various servers on the network. However, intermediate work products are often kept solely on workstations. Potential high value targets can be passively identified by comparing user email traffic against predefined profiles. This method provides a potentially smaller footprint on target systems, less human interaction, and increased efficiency of attackers. Collecting user email traffic and comparing each …


Quantifying Performance Bias In Label Fusion, Alexander M. Venzin Sep 2012

Quantifying Performance Bias In Label Fusion, Alexander M. Venzin

Theses and Dissertations

Classification systems are employed to remotely assess whether an element of interest falls into a target class or non-target class. These systems have uses in fields as far ranging as biostatistics to search engine keyword analysis. The performance of the system is often summarized as a trade-off between the proportions of elements correctly labeled as target plotted against the number of elements incorrectly labeled as target. These are empirical estimates of the true positive and false positive rates. These rates are often plotted to create a receiver operating characteristic (ROC) curve that acts as a visual tool to assess classification …


Mapping Nuclear Fallout Using The Weather Research & Forecasting (Wrf) Model, Joseph C. Schofield Sep 2012

Mapping Nuclear Fallout Using The Weather Research & Forecasting (Wrf) Model, Joseph C. Schofield

Theses and Dissertations

There are many models that attempt to predict transport & dispersion (T&D) of particulate matter in the sensible atmosphere. The majority of these existing models are unable to incorporate atmospheric processes such wet deposition through scavenging and cloud condensation nuclei (CCN) formation. To this end, the numerical weather prediction (NWP) model known as the Weather Research & Forecasting with Chemistry (WRF/Chem) Model is studied to determine its suitability as a potential tool for predicting particulate T&D following an atmospheric nuclear detonation. This is done by modifying relevant modules, originally designed to predict the settling of volcanic ash, such that a …


Eliciting A Sensemaking Process From Verbal Protocols Of Reverse Engineers, Adam R. Bryant, Robert F. Mills, Gilbert L. Peterson, Michael R. Grimaila Aug 2012

Eliciting A Sensemaking Process From Verbal Protocols Of Reverse Engineers, Adam R. Bryant, Robert F. Mills, Gilbert L. Peterson, Michael R. Grimaila

Faculty Publications

A process of sensemaking in reverse engineering was elicited from verbal protocols of reverse engineers as they investigated the assembly code of executable programs. Four participants were observed during task performance and verbal protocols were collected and analyzed from two of the participants to determine their problem-solving states and characterize likely transitions between those states. From this analysis, a high-level process of sensemaking is described which represents hypothesis generation and information-seeking behaviors in reverse engineering within a framework of goal-directed planning. Future work in validation and application of the process is discussed.


Using Modeling And Simulation To Examine The Benefits Of A Network Tasking Order, Matthew D. Compton, Kenneth M. Hopkinson, Gilbert L. Peterson, James T. Moore Jul 2012

Using Modeling And Simulation To Examine The Benefits Of A Network Tasking Order, Matthew D. Compton, Kenneth M. Hopkinson, Gilbert L. Peterson, James T. Moore

Faculty Publications

The Global Information Grid (GIG) is the military’s computer and communications network which supports the myriad of military missions. Military missions are highly planned, passing through many hands in the strategy-to-task methodology to ensure completeness, accuracy, coordination, cohesion, and appropriateness. A benefit of this planning is the possibility to collect knowledge of future conditions that could be of use to network designers whose goals include optimizing and protecting the GIG. This advanced knowledge includes which networked military equipment will be involved, what their capabilities are, where they will be, when they will be there, and particulars on the required data …


Design And Analysis Of A Dynamically Configured Log-Based Distributed Security Event Detection Methodology, Michael R. Grimaila, Justin Myers, Robert F. Mills, Gilbert L. Peterson Jul 2012

Design And Analysis Of A Dynamically Configured Log-Based Distributed Security Event Detection Methodology, Michael R. Grimaila, Justin Myers, Robert F. Mills, Gilbert L. Peterson

Faculty Publications

Military and defense organizations rely upon the security of data stored in, and communicated through, their cyber infrastructure to fulfill their mission objectives. It is essential to identify threats to the cyber infrastructure in a timely manner, so that mission risks can be recognized and mitigated. Centralized event logging and correlation is a proven method for identifying threats to cyber resources. However, centralized event logging is inflexible and does not scale well, because it consumes excessive network bandwidth and imposes significant storage and processing requirements on the central event log server. In this paper, we present a flexible, distributed event …


Enhancing Trust In The Smart Grid By Applying A Modified Exponentially Weighted Averages Algorithm, Andrew T. Kasperek Jun 2012

Enhancing Trust In The Smart Grid By Applying A Modified Exponentially Weighted Averages Algorithm, Andrew T. Kasperek

Theses and Dissertations

The main contribution of this thesis is the development and application of a modified Exponentially Weighted Moving Algorithm (EWMA) algorithm, and its ability to robustly function in the face varying numbers of bad (malicious or malfunctioning) Special Protection System (SPS) nodes. Simulation results support the use of the proposed modified EWMA reputation based trust module in SPSs within a smart grid environment. This modification results in the ability to easily maintain the system above the minimum acceptable frequency of 58.8 Hz at the 95% confidence interval, when challenged with test cases containing 5, 10 and 15 bad node test cases …


Cross Hallway Detection And Indoor Localization Using Flash Laser Detection And Ranging, Istvan M. Prileszky Jun 2012

Cross Hallway Detection And Indoor Localization Using Flash Laser Detection And Ranging, Istvan M. Prileszky

Theses and Dissertations

A flash LADAR is investigated as a source of navigation information to support cross-hallway detection and relative localization. To accomplish this, a dynamic, flexible simulation was developed that simulated the LADAR and the noise of a LADAR system. Using simulated LADAR data, algorithms were developed that were shown to be effective at detecting cross hallways in simulated ideal environments and in simulated environments with noise. Relative position was determined in the same situations. A SwissRanger SR4000 flash LADAR was then used to collect real data and to verify algorithm performance in real environments. Hallway detection was shown to be possible …


Decentralized Riemannian Particle Filtering With Applications To Multi-Agent Localization, Martin J. Eilders Jun 2012

Decentralized Riemannian Particle Filtering With Applications To Multi-Agent Localization, Martin J. Eilders

Theses and Dissertations

The primary focus of this research is to develop consistent nonlinear decentralized particle filtering approaches to the problem of multiple agent localization. A key aspect in our development is the use of Riemannian geometry to exploit the inherently non-Euclidean characteristics that are typical when considering multiple agent localization scenarios. A decentralized formulation is considered due to the practical advantages it provides over centralized fusion architectures. Inspiration is taken from the relatively new field of information geometry and the more established research field of computer vision. Differential geometric tools such as manifolds, geodesics, tangent spaces, exponential, and logarithmic mappings are used …


Vulnerability Analysis Of The Player Command And Control Protocol, John T. Hagen Jun 2012

Vulnerability Analysis Of The Player Command And Control Protocol, John T. Hagen

Theses and Dissertations

The Player project is an open-source effort providing a control interface specification and software framework for abstracting robot hardware. This research presents five exploits that compromise vulnerabilities in Player's command and control protocol. The attacks exploit weaknesses in the ARP, IP, TCP and Player protocols to compromise the confidentially, integrity, and availability of communication between a Player client and server. The attacks assume a laptop is connected in promiscuous mode to the same Ethernet hub as the client and server in order to sniff all network traffic between them. This work also demonstrates that Internet Protocol Security (IPsec) is capable …


Forensic Memory Analysis For Apple Os X, Andrew F. Hay Jun 2012

Forensic Memory Analysis For Apple Os X, Andrew F. Hay

Theses and Dissertations

Analysis of raw memory dumps has become a critical capability in digital forensics because it gives insight into the state of a system that cannot be fully represented through traditional disk analysis. Interest in memory forensics has grown steadily in recent years, with a focus on the Microsoft Windows operating systems. However, similar capabilities for Linux and Apple OS X have lagged by comparison. The volafox open source project has begun work on structured memory analysis for OS X. The tool currently supports a limited set of kernel structures to parse hardware information, system build number, process listing, loaded kernel …


Process Flow Features As A Host-Based Event Knowledge Representation, Benhur E. Pacer Jun 2012

Process Flow Features As A Host-Based Event Knowledge Representation, Benhur E. Pacer

Theses and Dissertations

The detection of malware is of great importance but even non-malicious software can be used for malicious purposes. Monitoring processes and their associated information can characterize normal behavior and help identify malicious processes or malicious use of normal process by measuring deviations from the learned baseline. This exploratory research describes a novel host feature generation process that calculates statistics of an executing process during a window of time called a process flow. Process flows are calculated from key process data structures extracted from computer memory using virtual machine introspection. Each flow cluster generated using k-means of the flow features represents …


Calibration Of A Silver Detector Using A Pube Source, Melanie E. Mace Jun 2012

Calibration Of A Silver Detector Using A Pube Source, Melanie E. Mace

Theses and Dissertations

During the initial design of the Field Reversed Compression and Heating Experiment (FRCHX), magnetohydrodynamic simulations performed by Los Alamos National Laboratory using MACH2 predicted a neutron yield on the order of 1012 neutrons. However, Air Force Research Laboratory (AFRL) measurements indicate a total of 107-108 neutrons are generated from the FRCHX. A PuBe source was used to create a burst of neutrons to calibrate an AFRL silver detector based on distance to determine if the four order of magnitude discrepancy was cause by an improperly calibrated detector. It was determined that the calibration equation in use …