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Articles 31 - 60 of 69
Full-Text Articles in Physical Sciences and Mathematics
Context Aware Routing Management Architecture For Airborne Networks, Joan A. Betances
Context Aware Routing Management Architecture For Airborne Networks, Joan A. Betances
Theses and Dissertations
This thesis advocates the use of Kalman filters in conjunction with network topology information derived from the Air Tasking Order (ATO) during the planning phase for military missions. This approach is the basis for an algorithm that implements network controls that optimize network performance for Mobile Ad hoc Networks (MANET). The trajectories of relevant nodes (airborne platforms) participating in the MANET can be forecasted by parsing key information contained in the ATO. This information is used to develop optimum network routes that can significantly improve MANET performance. Improved MANET performance in the battlefield enables decision makers to access information from …
Understanding How Reverse Engineers Make Sense Of Programs From Assembly Language Representations, Adam R. Bryant
Understanding How Reverse Engineers Make Sense Of Programs From Assembly Language Representations, Adam R. Bryant
Theses and Dissertations
This dissertation develops a theory of the conceptual and procedural aspects involved with how reverse engineers make sense of executable programs. Software reverse engineering is a complex set of tasks which require a person to understand the structure and functionality of a program from its assembly language representation, typically without having access to the program's source code. This dissertation describes the reverse engineering process as a type of sensemaking, in which a person combines reasoning and information foraging behaviors to develop a mental model of the program. The structure of knowledge elements used in making sense of executable programs are …
Detector Design Considerations In High-Dimensional Artificial Immune Systems, Jason M. Bindewald
Detector Design Considerations In High-Dimensional Artificial Immune Systems, Jason M. Bindewald
Theses and Dissertations
This research lays the groundwork for a network intrusion detection system that can operate with only knowledge of normal network traffic, using a process known as anomaly detection. Real-valued negative selection (RNS) is a specific anomaly detection algorithm that can be used to perform two-class classification when only one class is available for training. Researchers have shown fundamental problems with the most common detector shape, hyperspheres, in high-dimensional space. The research contained herein shows that the second most common detector type, hypercubes, can also cause problems due to biasing certain features in high dimensions. To address these problems, a new …
Towards Quantifying Programmable Logic Controller Resilience Against Intentional Exploits, Henry W. Bushey
Towards Quantifying Programmable Logic Controller Resilience Against Intentional Exploits, Henry W. Bushey
Theses and Dissertations
Supervisory Control and Data Acquisition (SCADA) systems control and monitor services for the nation's critical infrastructure. Recent cyber induced events (e.g., Stuxnet) provide an example of a targeted, covert cyber attack against a SCADA system that resulted in physical effects. Of particular note is how Stuxnet exploited the trust relationship between the human machine interface (HMI) and programmable logic controllers (PLCs). Current methods for validating system operating parameters rely on message exchange and network communications protocols, generally observed at the HMI. Although sufficient at the macro level, this method does not provide detection of malware that exhibits physical effects via …
Obfuscating Against Side-Channel Power Analysis Using Hiding Techniques For Aes, Austin W. Fritzke
Obfuscating Against Side-Channel Power Analysis Using Hiding Techniques For Aes, Austin W. Fritzke
Theses and Dissertations
The transfer of information has always been an integral part of military and civilian operations, and remains so today. Because not all information we share is public, it is important to secure our data from unwanted parties. Message encryption serves to prevent all but the sender and recipient from viewing any encrypted information as long as the key stays hidden. The Advanced Encryption Standard (AES) is the current industry and military standard for symmetric-key encryption. While AES remains computationally infeasible to break the encrypted message stream, it is susceptible to side-channel attacks if an adversary has access to the appropriate …
Magnesium Object Manager Sandbox, A More Effective Sandbox Method For Windows 7, Martin A. Gilligan
Magnesium Object Manager Sandbox, A More Effective Sandbox Method For Windows 7, Martin A. Gilligan
Theses and Dissertations
A major issue in computer security is limiting the affects a program can have on a computer. One way is to place the program into a sandbox, a limited environment. Many attempts have been made to create a sandbox that maintains the usability of a program and effectively limits the effects of the program. Sandboxes that limit the resources programs can access, have succeeded. To test the effectiveness of a sandbox that limits the resources a program can access on Windows 7, the Magnesium Object Manager Sandbox (MOMS) is created. MOMS uses a kernel mode Windows component to monitor and …
Scalable Wavelet-Based Active Network Stepping Stone Detection, Joseph I. Gilbert
Scalable Wavelet-Based Active Network Stepping Stone Detection, Joseph I. Gilbert
Theses and Dissertations
Network intrusions leverage vulnerable hosts as stepping stones to penetrate deeper into a network and mask malicious actions from detection. This research focuses on a novel active watermark technique using Discrete Wavelet Transformations to mark and detect interactive network sessions. This technique is scalable, nearly invisible and resilient to multi-flow attacks. The watermark is simulated using extracted timestamps from the CAIDA 2009 dataset and replicated in a live environment. The simulation results demonstrate that the technique accurately detects the presence of a watermark at a 5% False Positive and False Negative rate for both the extracted timestamps as well as …
An Analysis Of Error Reconciliation Protocols For Use In Quantum Key Distribution, James S. Johnson
An Analysis Of Error Reconciliation Protocols For Use In Quantum Key Distribution, James S. Johnson
Theses and Dissertations
Quantum Key Distribution (QKD) is a method for transmitting a cryptographic key between a sender and receiver in a theoretically unconditionally secure way. Unfortunately, the present state of technology prohibits the flawless quantum transmission required to make QKD a reality. For this reason, error reconciliation protocols have been developed which preserve security while allowing a sender and receiver to reconcile the errors in their respective keys. The most famous of these protocols is Brassard and Salvail's Cascade, which is effective, but suffers from a high communication complexity and therefore results in low throughput. Another popular option is Buttler's Winnow protocol, …
Evaluation Of Traditional Security Solutions In The Scada Environment, Robert D. Larkin
Evaluation Of Traditional Security Solutions In The Scada Environment, Robert D. Larkin
Theses and Dissertations
Supervisory Control and Data Acquisition (SCADA) systems control and monitor the electric power grid, water treatment facilities, oil and gas pipelines, railways, and other Critical Infrastructure (CI). In recent years, organizations that own and operate these systems have increasingly interconnected them with their enterprise network to take advantage of cost savings and operational benefits. This trend, however, has introduced myriad vulnerabilities associated with the networking environment. As a result, the once isolated systems are now susceptible to a wide range of threats that previously did not exist. To help address the associated risks, security professionals seek to incorporate mitigation solutions …
Evaluation Of Malware Target Recognition Deployed In A Cloud-Based Fileserver Environment, G. Parks Masters
Evaluation Of Malware Target Recognition Deployed In A Cloud-Based Fileserver Environment, G. Parks Masters
Theses and Dissertations
Cloud computing, or the migration of computing resources from the end user to remotely managed locations where they can be purchased on-demand, presents several new and unique security challenges. One of these challenges is how to efficiently detect malware amongst files that are possibly spread across multiple locations in the Internet over congested network connections. This research studies how such an environment will impact the performance of malware detection. A simplified cloud environment is created in which network conditions are fully controlled. This environment includes a fileserver, a detection server, the detection mechanism, and clean and malicious file sample sets. …
Binary Disassembly Block Coverage By Symbolic Execution Vs. Recursive Descent, Jonathan D. Miller
Binary Disassembly Block Coverage By Symbolic Execution Vs. Recursive Descent, Jonathan D. Miller
Theses and Dissertations
This research determines how appropriate symbolic execution is (given its current implementation) for binary analysis by measuring how much of an executable symbolic execution allows an analyst to reason about. Using the S2E Selective Symbolic Execution Engine with a built-in constraint solver (KLEE), this research measures the effectiveness of S2E on a sample of 27 Debian Linux binaries as compared to a traditional static disassembly tool, IDA Pro. Disassembly code coverage and path exploration is used as a metric for determining success. This research also explores the effectiveness of symbolic execution on packed or obfuscated samples of the same binaries …
Computer Aided Multi-Data Fusion Dismount Modeling, Juan L. Morales
Computer Aided Multi-Data Fusion Dismount Modeling, Juan L. Morales
Theses and Dissertations
Recent research efforts strive to address the growing need for dismount surveillance, dismount tracking and characterization. Current work in this area utilizes hyperspectral and multispectral imaging systems to exploit spectral properties in order to detect areas of exposed skin and clothing characteristics. Because of the large bandwidth and high resolution, hyperspectral imaging systems pose great ability to characterize and detect dismounts. A multi-data dismount modeling system where the development and manipulation of dismount models is a necessity. This thesis demonstrates a computer aided multi-data fused dismount model, which facilitates studies of dismount detection, characterization and identification. The system is created …
Covariance Analysis Of Vision Aided Navigation By Bootstrapping, Andrew L. Relyea
Covariance Analysis Of Vision Aided Navigation By Bootstrapping, Andrew L. Relyea
Theses and Dissertations
Inertial Navigation System (INS) aiding using bearing measurements taken over time of stationary ground features is investigated. A cross country flight, in two and three dimensional space, is considered, as well as a vertical drop in three dimensional space. The objective is to quantify the temporal development of the uncertainty in the navigation states of an aircraft INS which is aided by taking bearing measurements of ground objects which have been geolocated using ownship position. It is shown that during wings level flight at constant speed and a fixed altitude, an aircraft that tracks ground objects and over time sequentially …
Security Verification Of Secure Manet Routing Protocols, Matthew F. Steele
Security Verification Of Secure Manet Routing Protocols, Matthew F. Steele
Theses and Dissertations
Secure mobile ad hoc network (MANET) routing protocols are not tested thoroughly against their security properties. Previous research focuses on verifying secure, reactive, accumulation-based routing protocols. An improved methodology and framework for secure MANET routing protocol verification is proposed which includes table-based and proactive protocols. The model checker, SPIN, is selected as the core of the secure MANET verification framework. Security is defined by both accuracy and availability: a protocol forms accurate routes and these routes are always accurate. The framework enables exhaustive verification of protocols and results in a counter-example if the protocol is deemed insecure. The framework is …
Mfire-2: A Multi Agent System For Flow-Based Intrusion Detection Using Stochastic Search, Timothy J. Wilson
Mfire-2: A Multi Agent System For Flow-Based Intrusion Detection Using Stochastic Search, Timothy J. Wilson
Theses and Dissertations
Detecting attacks targeted against military and commercial computer networks is a crucial element in the domain of cyberwarfare. The traditional method of signature-based intrusion detection is a primary mechanism to alert administrators to malicious activity. However, signature-based methods are not capable of detecting new or novel attacks. This research continues the development of a novel simulated, multiagent, flow-based intrusion detection system called MFIRE. Agents in the network are trained to recognize common attacks, and they share data with other agents to improve the overall effectiveness of the system. A Support Vector Machine (SVM) is the primary classifier with which agents …
Turbulence Measurement In The Atmospheric Boundary Layer Using Cellular Telephone Signals, Lee R. Burchett
Turbulence Measurement In The Atmospheric Boundary Layer Using Cellular Telephone Signals, Lee R. Burchett
Theses and Dissertations
This thesis investigated a new method for measuring the intensity of turbulence in the planetary boundary layer that shows a high correlation with measurements from weather radar. The method takes measurements of cell phone signal strength and uses scintillation in the signal to estimate the strength of local turbulence. Using cell phone signals provides unique measurement advantages: it is a passive measurement method, it is not strongly affected by precipitation, and one device can potentially measure several paths at once. The measurements were taken using an Android® cell phone running a custom built application. The strength of turbulence was quantified …
3-D Scene Reconstruction From Aerial Imagery, Jared M. Ekholm
3-D Scene Reconstruction From Aerial Imagery, Jared M. Ekholm
Theses and Dissertations
3-D scene reconstructions derived from Structure from Motion (SfM) and Multi-View Stereo (MVS) techniques were analyzed to determine the optimal reconnaissance flight characteristics suitable for target reconstruction. In support of this goal, a preliminary study of a simple 3-D geometric object facilitated the analysis of convergence angles and number of camera frames within a controlled environment. Reconstruction accuracy measurements revealed at least 3 camera frames and a 6 convergence angle were required to achieve results reminiscent of the original structure. The central investigative effort sought the applicability of certain airborne reconnaissance flight profiles to reconstructing ground targets. The data sets …
Collisional Dynamics, Lasing And Stimulated Raman Scattering In Optically Pumped Cesium And Potassium Vapors, Kirk C. Brown
Collisional Dynamics, Lasing And Stimulated Raman Scattering In Optically Pumped Cesium And Potassium Vapors, Kirk C. Brown
Theses and Dissertations
This dissertation explores collisional dynamics, lasing and stimulated Raman scattering in cesium and potassium vapors. The spin orbit mixing and quenching cross sections of several buffer gas species are measured. The ne-structure mixing cross sections for He, CH4 and C2H6 are 14±3, 35±6 and 73±10 °A2, respectively. The 2P3/2 state is quenched more rapidly than the 2P1/2 state. A pulsed blue laser operating via direct excitation of the cesium 72P3/2 state is demonstrated. A theoretical model is extended and compared with experimental results. The maximum output …
Ensemble Forecasting Of Coronal Mass Ejections Using The Wsa-Enlil With Coned Model, Daniel J. Emmons Ii
Ensemble Forecasting Of Coronal Mass Ejections Using The Wsa-Enlil With Coned Model, Daniel J. Emmons Ii
Theses and Dissertations
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 (CME's). The input parameter distributions were formed from 100 sets of CME cone parameters derived from the Coned Model. The Coned Model employed 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 …
Matrix Determination Of Reflectivity Of Hidden Object Via Indirect Photography, Simon S. Ferrel
Matrix Determination Of Reflectivity Of Hidden Object Via Indirect Photography, Simon S. Ferrel
Theses and Dissertations
Indirect photography is a recently demonstrated technique which expands on the principles of dual photography and allows for the imaging of hidden objects. A camera and light source are collocated with neither having line-of-sight access to the hidden object. Light from the source, a laser, is reflected off a visible non-specular surface onto the hidden object, where it is reflected back to the initial non-specular surface and collected by the camera. This process may be repeated numerous times for various laser spot positions to yield slightly different camera images due to a variation in the illumination of the object. These …
Design And Characterization Of A Three-Dimensional Positron Annihilation Spectroscopy System Using A Low-Energy Positron Beam, Stephen M. Jimenez
Design And Characterization Of A Three-Dimensional Positron Annihilation Spectroscopy System Using A Low-Energy Positron Beam, Stephen M. Jimenez
Theses and Dissertations
Previous forays by AFIT into positron research have resulted in the development of a new positron annihilation spectroscopy (PAS) technique and the procurement of a low-energy positron beam system. The primary purpose of this research was to design and build a state-of-the-art PAS laboratory at AFIT capable to address a myriad of DoD solid-state and surface physics questions. The main objectives were to acquire and assemble utilities to operate a positron beam, assemble and configure an ultra-high vacuum (UHV) system for samples, design and build an interface with a magnetic field to propagate positrons onto samples, and create a new …
Positron Lifetime Modulation By Electric Field Induced Positronium Formation On A Gold Surface, Daniel J. Higgins
Positron Lifetime Modulation By Electric Field Induced Positronium Formation On A Gold Surface, Daniel J. Higgins
Theses and Dissertations
The purpose of this project is to study the lifetime and annihilation mode of positrons, the antimatter counterpart to electrons, and the formation rate of positronium on a gold surface modified by gold nanoparticles under the influence of radial electric fields measured using two independent systems. The positron annihilation photon pair/triplet spectroscopy system uses a sodium iodide ring detector segmented into six detection regions providing rough position sensitivity to measure the ratio of two to three photon positron annihilation events. An increased rate of three photon annihilation events and a decreased rate of two photon annihilation events are observed when …
Comparative Statistical Analysis Of Auroral Models, Cory T. Lane
Comparative Statistical Analysis Of Auroral Models, Cory T. Lane
Theses and Dissertations
The location of the equatorward boundary of the auroral oval provides an appropriate means to measure the accuracy of auroral models. In this study, the equatorward boundary is represented by the location at which the energy flux data measured by DMSP satellites exceeds 0.4 erg/cm2/s. The MLAT coordinates obtained from more than 4,000 orbits through the polar region of the Northern Hemisphere comprise the data set used to compare to the outputs of five auroral models. These models are: the original Hardy auroral model of 1985 (OH), the OVATION Prime model (OP), the 2008 adaptation to the Hardy …
Durability Of Mwcnt Composites Under Electron And Neutron Irradiation, Quan-Hai T. Lu
Durability Of Mwcnt Composites Under Electron And Neutron Irradiation, Quan-Hai T. Lu
Theses and Dissertations
Electromagnetic interference shielding effectiveness and conductive properties of carbon nanotube containing composites intended for use as satellite surface materials have been investigated following electron and neutron irradiation. The MWCNT composites were irradiated to fluence levels of 1016 electrons/cm2 with 500 keV electrons. Increase in EMI-SE and conductivity was observed following electron irradiation in two of the samples. The sample with alternating layers of MWCNT and glass had a decrease in conductivity and an increase in EMI-SE post irradiation. This would suggest that the different layered configuration does play a role in the durability of the composite. Having multiple …
Spectral And Spatial Coherent Emission Of Thermal Radiation From Metal-Semiconductor Nanostructures, Shane N. Mcconnell
Spectral And Spatial Coherent Emission Of Thermal Radiation From Metal-Semiconductor Nanostructures, Shane N. Mcconnell
Theses and Dissertations
The spectral and spatial radiative properties of coherent thermal emission in the mid- and far-IR through the use of micro and nano-structured metal-semiconductor materials were designed and demonstrated experimentally. Using an implementation of the Rigorous Coupled Wave Analysis and Computer Simulation Technology (CST), two structures were designed to selectively emit at mid- and far-IR wavelengths, a 1-D truncated multilayer resonator and a 3-D hybrid photonic crystal (PC)-multilayer. A High Impulse Power Magnetron Sputtering (HIPIMS) deposition technique was used to fabricate two silver-germanium-silver (Ag-Ge-Ag) resonating structures with layer thicknesses of 6-240-160 nm for one sample and 6-700-200 nm for the other. …
Cesium Absorption Spectrum Perturbed By Argon: Observation Of Non-Lorentzian Far Wings, Gordon E. Lott
Cesium Absorption Spectrum Perturbed By Argon: Observation Of Non-Lorentzian Far Wings, Gordon E. Lott
Theses and Dissertations
The purpose of this research was to observe the core and far wing absorption spectra of the D1 and D2 lines of cesium (Cs) perturbed by argon (Ar). A 1.33 m scanning monochromator with a PMT detector was used to measure the spectra from 8300 Å to 9100 Å. A heat pipe was used to control the Cs concentration and Ar pressure allowing for a broad range of spectra to be collected. Spectra were collected for heat pipe temperatures of 50, 75, 100, 125, 150 and 175 °C, corresponding to Cs concentrations of approximately 6×1011, 4×10 …
Neutron Detection Using Amorphous Boron-Carbide Hetero-Junction Diodes, Thomas P. Mcquary
Neutron Detection Using Amorphous Boron-Carbide Hetero-Junction Diodes, Thomas P. Mcquary
Theses and Dissertations
The high energy products of the 10B(n,α)7Li neutron capture reaction were explored as a means of thermal neutron detection in thin film amorphous boron carbide (a--B5C:Hx) on n-type silicon hetero-junction diodes. Pulse height spectroscopy was conducted on the diodes while they were subjected to a moderated plutonium-beryllium (PuBe) source. Neutron capture could not be confirmed experimentally in any of the devices tested. Device modeling was performed to investigate the cause for the diode detector's negative response. A 1.47 MeV α particle produced transient current of 10-7 A and the induced was 4.7 …
The Focusing Of Light Scattered From Diffuse Reflectors Using Phase Modulation, Jessica M. Schafer
The Focusing Of Light Scattered From Diffuse Reflectors Using Phase Modulation, Jessica M. Schafer
Theses and Dissertations
“Indirect photography" was recently demonstrated for imaging hidden scene information through the collection and radiometric modeling of light reflecting off of visible reflecting surfaces. The ability to focus the beam that reflects off the visible surface to a tight spot on the hidden object is theorized to simulate a direct line of sight from the light source to the object, reducing the radiometric model to that of the previously demonstrated dual photography. Experiments involving the focusing of light transmitted through highly scattering media have been adapted to the case of reflection. The focusing of a HeNe laser reflected off diffusely …
Ladar Performance Simulations With A High Spectral Resolution Atmospheric Transmittance And Radiance Model- Leedr, Benjamin D. Roth
Ladar Performance Simulations With A High Spectral Resolution Atmospheric Transmittance And Radiance Model- Leedr, Benjamin D. Roth
Theses and Dissertations
In this study of atmospheric effects on Geiger Mode laser ranging and detection (LADAR), the parameter space is explored primarily using the Air Force Institute of Technology Center for Directed Energy's (AFIT/CDE) Laser Environmental Effects Definition and Reference (LEEDR) code. The LADAR system is assessed at operationally representative wavelengths of 1.064, 1.56 and 2.039 μm with several up and down looking engagement geometries at locations worldwide. Results computed with LEEDR are compared to standard atmosphere and Fast Atmospheric Signature Code (FASCODE) assessments. Results show significant climate dependence, but large variances between climatological and standard atmosphere assessments. An overall average absolute …
Using Multiattribute Utility Copulas In Support Of Uav Search And Destroy Operations, Beau A. Nunnally
Using Multiattribute Utility Copulas In Support Of Uav Search And Destroy Operations, Beau A. Nunnally
Theses and Dissertations
The multiattribute utility copula is an emerging form of utility function used by decision analysts to study decisions with dependent attributes. Failure to properly address attribute dependence may cause errors in selecting the optimal policy. This research examines two scenarios of interest to the modern warfighter. The first scenario employs a utility copula to determine the type, quantity, and altitude of UAVs to be sent to strike a stationary target. The second scenario employs a utility copula to examine the impact of attribute dependence on the optimal routing of UAVs in a contested operational environment when performing a search and …