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Articles 1 - 30 of 34
Full-Text Articles in Physical Sciences and Mathematics
Steganalysis Embedding Percentage Determination With Learning Vector Quantization, Benjamin M. Rodriguez, Gilbert L. Peterson, Kenneth W. Bauer, Sos S. Agaian
Steganalysis Embedding Percentage Determination With Learning Vector Quantization, Benjamin M. Rodriguez, Gilbert L. Peterson, Kenneth W. Bauer, Sos S. Agaian
Faculty Publications
Steganography (stego) is used primarily when the very existence of a communication signal is to be kept covert. Detecting the presence of stego is a very difficult problem which is made even more difficult when the embedding technique is not known. This article presents an investigation of the process and necessary considerations inherent in the development of a new method applied for the detection of hidden data within digital images. We demonstrate the effectiveness of learning vector quantization (LVQ) as a clustering technique which assists in discerning clean or non-stego images from anomalous or stego images. This comparison is conducted …
Optimizing The Replication Of Multi-Quality Web Applications Using Aco And Wolf, Judson C. Dressler
Optimizing The Replication Of Multi-Quality Web Applications Using Aco And Wolf, Judson C. Dressler
Theses and Dissertations
This thesis presents the adaptation of Ant Colony Optimization to a new NP-hard problem involving the replication of multi-quality database-driven web applications (DAs) by a large application service provider (ASP). The ASP must assign DA replicas to its network of heterogeneous servers so that user demand is satisfied and replica update loads are minimized. The algorithm proposed, AntDA, for solving this problem is novel in several respects: ants traverse a bipartite graph in both directions as they construct solutions, pheromone is used for traversing from one side of the bipartite graph to the other and back again, heuristic edge values …
Fuzzy State Aggregation And Policy Hill Climbing For Stochastic Environments, Dean C. Wardell, Gilbert L. Peterson
Fuzzy State Aggregation And Policy Hill Climbing For Stochastic Environments, Dean C. Wardell, Gilbert L. Peterson
Faculty Publications
Reinforcement learning is one of the more attractive machine learning technologies, due to its unsupervised learning structure and ability to continually learn even as the operating environment changes. Additionally, by applying reinforcement learning to multiple cooperative software agents (a multi-agent system) not only allows each individual agent to learn from its own experience, but also opens up the opportunity for the individual agents to learn from the other agents in the system, thus accelerating the rate of learning. This research presents the novel use of fuzzy state aggregation, as the means of function approximation, combined with the fastest policy hill …
New Tracking Filter Algorithm Using Input Parameter Estimation, Corey M. Broussard
New Tracking Filter Algorithm Using Input Parameter Estimation, Corey M. Broussard
Theses and Dissertations
A new method for the design of tracking filters for maneuvering targets, based on kinematic models and input signals estimation, is developed. The input signal's level, u is considered a continuous variable and consequently the input estimation problem is posed as a purely parameter estimation problem. Moreover, the application of the new tracking filter algorithm is not contingent on distinguishing maneuvering and non-maneuvering targets, and does not require the detection of maneuver onset. The filter will automatically detect the onset of a maneuver. Furthermore, an estimate of the target's acceleration is also obtained with reasonable precision. This opens the door …
Development And Testing Of A High-Speed Real-Time Kinematic Precise Dgps Positioning System Between Two Aircraft, Christopher J. Spinelli
Development And Testing Of A High-Speed Real-Time Kinematic Precise Dgps Positioning System Between Two Aircraft, Christopher J. Spinelli
Theses and Dissertations
This research involves the design, implementation, and testing of a high-speed, real-time kinematic, precise differential GPS positioning system for use in airborne applications such as automated aerial-refueling and close formation flying. Although many of the current ambiguity resolution techniques use the residuals from the least squares position estimation to determine the true ambiguity set, this thesis presents a novel approach to the ambiguity resolution problem, called the minimum indicator. Instead of assuming the ambiguity set with the lowest residuals is the true set, other special characteristics of the residuals are examined. This increases the confidence that the algorithm has selected …
A Multidiscipline Approach To Mitigating The Insider Threat, Jonathan W. Butts, Robert F. Mills, Gilbert L. Peterson
A Multidiscipline Approach To Mitigating The Insider Threat, Jonathan W. Butts, Robert F. Mills, Gilbert L. Peterson
Faculty Publications
Preventing and detecting the malicious insider is an inherently difficult problem that expands across many areas of expertise such as social, behavioral and technical disciplines. Unfortunately, current methodologies to combat the insider threat have had limited success primarily because techniques have focused on these areas in isolation. The technology community is searching for technical solutions such as anomaly detection systems, data mining and honeypots. The law enforcement and counterintelligence communities, however, have tended to focus on human behavioral characteristics to identify suspicious activities. These independent methods have limited effectiveness because of the unique dynamics associated with the insider threat. The …
Development Of A Methodology For Customizing Insider Threat Auditing On A Microsoft Windows Xp® Operating System, Terry E. Levoy
Development Of A Methodology For Customizing Insider Threat Auditing On A Microsoft Windows Xp® Operating System, Terry E. Levoy
Theses and Dissertations
Most organizations are aware that threats from trusted insiders pose a great risk to their organization and are very difficult to protect against. Auditing is recognized as an effective technique to detect malicious insider activities. However, current auditing methods are typically applied with a one-size-fits-all approach and may not be an appropriate mitigation strategy, especially towards insider threats. This research develops a 4-step methodology for designing a customized auditing template for a Microsoft Windows XP operating system. Two tailoring methods are presented which evaluate both by category and by configuration. Also developed are various metrics and weighting factors as a …
Robot Localization Using Visual Image Mapping, Carrie D. Crews
Robot Localization Using Visual Image Mapping, Carrie D. Crews
Theses and Dissertations
One critical step in providing the Air Force the capability to explore unknown environments is for an autonomous agent to be able to determine its location. The calculation of the robot's pose is an optimization problem making use of the robot's internal navigation sensors and data fusion of range sensor readings to find the most likely pose. This data fusion process requires the simultaneous generation of a map which the autonomous vehicle can then use to avoid obstacles, communicate with other agents in the same environment, and locate targets. Our solution entails mounting a Class 1 laser to an ERS-7 …
Mitigating Insider Threat Using Human Behavior Influence Models, Anthony J. Puleo
Mitigating Insider Threat Using Human Behavior Influence Models, Anthony J. Puleo
Theses and Dissertations
Insider threat is rapidly becoming the largest information security problem that organizations face. With large numbers of personnel having access to internal systems, it is becoming increasingly difficult to protect organizations from malicious insiders. The typical methods of mitigating insider threat are simply not working, primarily because this threat is a people problem, and most mitigation strategies are geared towards profiling and anomaly detection, which are problematic at best. As a result, a new type of model is proposed in this thesis, one that incorporates risk management with human behavioral science. The new risk-based model focuses on observable influences that …
Afit Uav Swarm Mission Planning And Simulation System, James N. Slear
Afit Uav Swarm Mission Planning And Simulation System, James N. Slear
Theses and Dissertations
The purpose of this research is to design and implement a comprehensive mission planning system for swarms of autonomous aerial vehicles. The system integrates several problem domains including path planning, vehicle routing, and swarm behavior. The developed system consists of a parallel, multi-objective evolutionary algorithm-based path planner, a genetic algorithm-based vehicle router, and a parallel UAV swarm simulator. Each of the system's three primary components are developed on AFIT's Beowulf parallel computer clusters. Novel aspects of this research include: integrating terrain following technology into a swarm model as a means of detection avoidance, combining practical problems of path planning and …
Development Of A Malicious Insider Composite Vulnerability Assessment Methodology, William H. King
Development Of A Malicious Insider Composite Vulnerability Assessment Methodology, William H. King
Theses and Dissertations
Trusted employees pose a major threat to information systems. Despite advances in prevention, detection, and response techniques, the number of malicious insider incidents and their associated costs have yet to decline. There are very few vulnerability and impact models capable of providing information owners with the ability to comprehensively assess the effectiveness an organization's malicious insider mitigation strategies. This research uses a multi-dimensional approach: content analysis, attack tree framework, and an intent driven taxonomy model are used to develop a malicious insider Decision Support System (DSS) tool. The DSS tool's utility and applicability is demonstrated using a notional example. This …
Mitigating Tcp Degradation Over Intermittent Link Failures Using Intermediate Buffers, M. Brent Reynolds
Mitigating Tcp Degradation Over Intermittent Link Failures Using Intermediate Buffers, M. Brent Reynolds
Theses and Dissertations
This thesis addresses the improvement of data transmission performance in a challenged network. It is well known that the popular Transmission Control Protocol degrades in environments where one or more of the links along the route is intermittently available. To avoid this degradation, this thesis proposes placing at least one node along the path of transmission to buffer and retransmit as needed to overcome the intermittent link. In the four-node, three-link testbed under particular conditions, file transmission time was reduced 20 fold in the case of an intermittent second link when the second node strategically buffers for retransmission opportunity.
Multiple Masks-Based Pixel Comparison Steganalysis Method For Mobile Imaging, Sos S. Agaian, Gilbert L. Peterson, Benjamin M. Rodriguez
Multiple Masks-Based Pixel Comparison Steganalysis Method For Mobile Imaging, Sos S. Agaian, Gilbert L. Peterson, Benjamin M. Rodriguez
Faculty Publications
No abstract provided.
Fuzzy State Aggregation And Off-Policy Reinforcement Learning For Stochastic Environments, Dean C. Wardell, Gilbert L. Peterson
Fuzzy State Aggregation And Off-Policy Reinforcement Learning For Stochastic Environments, Dean C. Wardell, Gilbert L. Peterson
Faculty Publications
Reinforcement learning is one of the more attractive machine learning technologies, due to its unsupervised learning structure and ability to continually learn even as the environment it is operating in changes. This ability to learn in an unsupervised manner in a changing environment is applicable in complex domains through the use of function approximation of the domain’s policy. The function approximation presented here is that of fuzzy state aggregation. This article presents the use of fuzzy state aggregation with the current policy hill climbing methods of Win or Lose Fast (WoLF) and policy-dynamics based WoLF (PD-WoLF), exceeding the learning rate …
An Interactive Relaxation Approach For Anomaly Detection And Preventive Measures In Computer Networks, Garrick A. Bell
An Interactive Relaxation Approach For Anomaly Detection And Preventive Measures In Computer Networks, Garrick A. Bell
Theses and Dissertations
It is proposed to develop a framework of detecting and analyzing small and widespread changes in specific dynamic characteristics of several nodes. The characteristics are locally measured at each node in a large network of computers and analyzed using a computational paradigm known as the Relaxation technique. The goal is to be able to detect the onset of a worm or virus as it originates, spreads-out, attacks and disables the entire network. Currently, selective disabling of one or more features across an entire subnet, e.g. firewalls, provides limited security and keeps us from designing high performance net-centric systems. The most …
Factors Impacting Key Management Effectiveness In Secured Wireless Networks, Yongjoo Shin
Factors Impacting Key Management Effectiveness In Secured Wireless Networks, Yongjoo Shin
Theses and Dissertations
The use of a Public Key Infrastructure (PKI) offers a cryptographic solution that can overcome many, but not all, of the MANET security problems. One of the most critical aspects of a PKI system is how well it implements Key Management. Key Management deals with key generation, key storage, key distribution, key updating, key revocation, and certificate service in accordance with security policies over the lifecycle of the cryptography. The approach supported by traditional PKI works well in fixed wired networks, but it may not appropriate for MANET due to the lack of fixed infrastructure to support the PKI. This …
Type Ii Quantum Computing Algorithm For Computational Fluid Dynamics, James A. Scoville
Type Ii Quantum Computing Algorithm For Computational Fluid Dynamics, James A. Scoville
Theses and Dissertations
An algorithm is presented to simulate fluid dynamics on a three qubit type II quantum computer: a lattice of small quantum computers that communicate classical information. The algorithm presented is called a three qubit factorized quantum lattice gas algorithm. It is modeled after classical lattice gas algorithms which move virtual particles along an imaginary lattice and change the particles’ momentums using collision rules when they meet at a lattice node. Instead of moving particles, the quantum algorithm presented here moves probabilities, which interact via a unitary collision operator. Probabilities are determined using ensemble measurement and are moved with classical communications …
Formal Mitigation Strategies For The Insider Threat: A Security Model And Risk Analysis Framework, Jonathan W. Butts
Formal Mitigation Strategies For The Insider Threat: A Security Model And Risk Analysis Framework, Jonathan W. Butts
Theses and Dissertations
The advancement of technology and reliance on information systems have fostered an environment of sharing and trust. The rapid growth and dependence on these systems, however, creates an increased risk associated with the insider threat. The insider threat is one of the most challenging problems facing the security of information systems because the insider already has capabilities within the system. Despite research efforts to prevent and detect insiders, organizations remain susceptible to this threat because of inadequate security policies and a willingness of some individuals to betray their organization. To investigate these issues, a formal security model and risk analysis …
Toward The Static Detection Of Deadlock In Java Software, Jose E. Fadul
Toward The Static Detection Of Deadlock In Java Software, Jose E. Fadul
Theses and Dissertations
Concurrency is the source of many real-world software reliability and security problems. Concurrency defects are difficult to detect because they defy conventional software testing techniques due to their non-local and non-deterministic nature. We focus on one important aspect of this problem: static detection of the possibility of deadlock - a situation in which two or more processes are prevented from continuing while each waits for resources to be freed by the continuation of the other. This thesis proposes a flow-insensitive interprocedural static analysis that detects the possibility that a program can deadlock at runtime. Our analysis proceeds in two steps. …
An Adaptable Energy-Efficient Medium Access Control Protocol For Wireless Sensor Networks, Justin T. Kautz
An Adaptable Energy-Efficient Medium Access Control Protocol For Wireless Sensor Networks, Justin T. Kautz
Theses and Dissertations
Wireless networks have become ubiquitous recently and therefore their usefulness has also become more extensive. Wireless sensor networks (WSN) detect environmental information with sensors in remote settings. One problem facing WSNs is the inability to resupply power to these energy-constrained devices due to their remoteness. Therefore to extend a WSN's effectiveness, the lifetime of the network must be increased by making them as energy efficient as possible. An energy efficient medium access control (MAC) can boost a WSN's lifetime. This research creates a MAC protocol called Adaptive sensor Medium Access Control (AMAC) which is based on Sensor Medium Access Control …
Evolving Self-Organized Behavior For Homogeneous And Heterogeneous Uav Or Ucav Swarms, Ian C. Price
Evolving Self-Organized Behavior For Homogeneous And Heterogeneous Uav Or Ucav Swarms, Ian C. Price
Theses and Dissertations
This investigation uses a self-organization (SO) approach to enable cooperative search and destruction of retaliating targets with swarms of homogeneous and heterogeneous unmanned aerial vehicles (UAVs). To facilitate specific system design, a facilitating SO algebraic framework is created that emphasizes scalability, robustness, and flexibility. This framework is then used to implement a UAV behavior architecture relying upon rules governing formation and target interaction. Sets of applicable behaviors are created by weighted summation of the rules where different weights act as distinct behavior archetypes. Appropriate behavior archetypes are based upon sense information distilled from the environment and a simple perceptron mapping. …
Multiframe Shift Estimation, Stephen A. Bruckart
Multiframe Shift Estimation, Stephen A. Bruckart
Theses and Dissertations
The purpose of this research was to develop a fundamental framework for a new approach to multiframe translational shift estimation in image processing. This thesis sought to create a new multiframe shift estimator, to theoretically prove and experimentally test key properties of it, and to quantify its performance according to several metrics. The new estimator was modeled successfully and was proven to be an unbiased estimator under certain common image noise conditions. Furthermore its performance was shown to be superior to the cross correlation shift estimator, a robust estimator widely used in similar image processing cases, according to several criteria. …
Mitigating Distributed Denial Of Service Attacks In An Anonymous Routing Environment: Client Puzzles And Tor, Nicholas A. Fraser
Mitigating Distributed Denial Of Service Attacks In An Anonymous Routing Environment: Client Puzzles And Tor, Nicholas A. Fraser
Theses and Dissertations
Online intelligence operations use the Internet to gather information on the activities of U.S. adversaries. The security of these operations is paramount, and one way to avoid being linked to the Department of Defense (DoD) is to use anonymous communication systems. One such system, Tor, makes interactive TCP services anonymous. Tor uses the Transport Layer Security (TLS) protocol and is thus vulnerable to a distributed denial-of-service (DDoS) attack that can significantly delay data traversing the Tor network. This research uses client puzzles to mitigate TLS DDoS attacks. A novel puzzle protocol, the Memoryless Puzzle Protocol (MPP), is conceived, implemented, and …
Verification Of A Decision Level Fusion Algorithm Using A Proven Atr System And Measured Sar Data, James Douglas Thompson
Verification Of A Decision Level Fusion Algorithm Using A Proven Atr System And Measured Sar Data, James Douglas Thompson
Theses and Dissertations
Decision level fusion (DLF) algorithms combine outputs of multiple single sensors to make one confident declaration of a target. This research compares performance results of a DLF algorithm using measured data and a proven ATR system with results from simulated data and a modeled ATR system. This comparison indicates that DLF offers significant performance improvements over single sensor looks. However, results based on simulated data and a modeled ATR are slightly optimistic and overestimate results from measured data and a proven ATR system by nearly 10% over all targets tested.
A Monocular Vision Based Approach To Flocking, Brian Kirchner
A Monocular Vision Based Approach To Flocking, Brian Kirchner
Theses and Dissertations
Flocking is seen in nature as a means for self protection, more efficient foraging, and other search behaviors. Although much research has been done regarding the application of this principle to autonomous vehicles, the majority of the research has relied on GPS information, broadcast communication, an omniscient central controller, or some other form of "global" knowledge. This approach, while effective, has serious drawbacks, especially regarding stealth, reliability, and biological grounding. This research effort uses three Pioneer P2-AT8 robots to achieve flocking behavior without the use of global knowledge. The sensory inputs are limited to two cameras, offset such that the …
Cryptanalysis Of Pseudorandom Number Generators In Wireless Sensor Networks, Kevin M. Finnigin
Cryptanalysis Of Pseudorandom Number Generators In Wireless Sensor Networks, Kevin M. Finnigin
Theses and Dissertations
This work presents a brute-force attack on an elliptic curve cryptosystem implemented on UC Berkley's TinyOS operating system for wireless sensor networks. The attack exploits the short period of the pseudorandom number generator (PRNG) used by the cryptosystem to generate private keys. The attack assumes a laptop is listening promiscuously to network traffic for key messages and requires only the sensor node?s public key and network address to discover the private key. Experimental results show that roughly 50% of the address space leads to a private key compromise in 25 minutes on average. Furthermore, approximately 32% of the address space …
Detecting Potential Insider Threats Through Email Datamining, James S. Okolica
Detecting Potential Insider Threats Through Email Datamining, James S. Okolica
Theses and Dissertations
No abstract provided.
Application Of Fuzzy State Aggregation And Policy Hill Climbing To Multi-Agent Systems In Stochastic Environments, Dean C. Wardell
Application Of Fuzzy State Aggregation And Policy Hill Climbing To Multi-Agent Systems In Stochastic Environments, Dean C. Wardell
Theses and Dissertations
Reinforcement learning is one of the more attractive machine learning technologies, due to its unsupervised learning structure and ability to continually even as the operating environment changes. Applying this learning to multiple cooperative software agents (a multi-agent system) not only allows each individual agent to learn from its own experience, but also opens up the opportunity for the individual agents to learn from the other agents in the system, thus accelerating the rate of learning. This research presents the novel use of fuzzy state aggregation, as the means of function approximation, combined with the policy hill climbing methods of Win …
Bda Enhancement Methodology Using Situational Parameter Adjustments, Michael V. Carras Jr.
Bda Enhancement Methodology Using Situational Parameter Adjustments, Michael V. Carras Jr.
Theses and Dissertations
In the context of close ground combat, the perception of Battle Damage Assessment (BDA) is closely linked with a soldier’s engagement decisions and has significant effects on the battlefield. Perceived BDA is also one of the most complex and uncertain processes facing the soldier in live combat. As a result, the modeling and simulation community has yet to adequately model the perceived BDA process in combat models. This research effort examines the BDA process from a perception standpoint and proposes a methodology to collect the pertinent data and model this perception in the Army’s current force-on-force model, CASTFOREM. A subject …
A Comparison Of Main Rotor Smoothing Adjustments Using Linear And Neural Network Algorithms, Nathan A. Miller
A Comparison Of Main Rotor Smoothing Adjustments Using Linear And Neural Network Algorithms, Nathan A. Miller
Theses and Dissertations
Helicopter main rotor smoothing is a maintenance procedure that is routinely performed to minimize airframe vibrations induced by non-uniform mass and/or aerodynamic distributions in the main rotor system. This important task is both time consuming and expensive, so improvements to the process have long been sought. Traditionally, vibrations have been minimized by calculating adjustments based on an assumed linear relationship between adjustments and vibration response. In recent years, artificial neural networks have been trained to recognize non-linear mappings between adjustments and vibration response. This research was conducted in order observe the character of the adjustment mapping of the Vibration Management …