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Physical Sciences and Mathematics Commons

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Articles 1 - 9 of 9

Full-Text Articles in Physical Sciences and Mathematics

A Taxonomy For And Analysis Of Anonymous Communications Networks, Douglas J. Kelly Mar 2009

A Taxonomy For And Analysis Of Anonymous Communications Networks, Douglas J. Kelly

Theses and Dissertations

Any entity operating in cyberspace is susceptible to debilitating attacks. With cyber attacks intended to gather intelligence and disrupt communications rapidly replacing the threat of conventional and nuclear attacks, a new age of warfare is at hand. In 2003, the United States acknowledged that the speed and anonymity of cyber attacks makes distinguishing among the actions of terrorists, criminals, and nation states difficult. Even President Obama’s Cybersecurity Chief-elect recognizes the challenge of increasingly sophisticated cyber attacks. Now through April 2009, the White House is reviewing federal cyber initiatives to protect US citizen privacy rights. Indeed, the rising quantity and ubiquity …


Using Covert Means To Establish Cybercraft Command And Control, Bradley D. Sevy Mar 2009

Using Covert Means To Establish Cybercraft Command And Control, Bradley D. Sevy

Theses and Dissertations

With the increase in speed and availability of computers, our nation's computer and information systems are being attacked with increased sophistication. The Air Force Research Laboratory (AFRL) Information Directorate (RI) is researching a next generation network defense architecture, called Cybercraft, that provides automated and trusted cyber defense capabilities for AF network assets. This research we consider the issues to protect or obfuscate command and control aspects of Cybercraft. In particular, we present a methodology to hide aspects of Cybercraft platform initialization in context to formation of hierarchical, peer-to-peer groups that collectively form the Cybercraft network. Because malicious code networks (known …


Low Probability Of Intercept Waveforms Via Intersymbol Dither Performance Under Multipath Conditions, Jonathan K. Keen Mar 2009

Low Probability Of Intercept Waveforms Via Intersymbol Dither Performance Under Multipath Conditions, Jonathan K. Keen

Theses and Dissertations

This thesis examines the effects of multipath interference on Low Probability of Intercept (LPI) waveforms generated using intersymbol dither. LPI waveforms are designed to be difficult for non-cooperative receivers to detect and manipulate, and have many uses in secure communications applications. In prior research, such a waveform was designed using a dither algorithm to vary the time between the transmission of data symbols in a communication system. This work showed that such a method can be used to frustrate attempts to use non-cooperative receiver algorithms to recover the data. This thesis expands on prior work by examining the effects of …


Image Processing For Multiple-Target Tracking On A Graphics Processing Unit, Michael A. Tanner Mar 2009

Image Processing For Multiple-Target Tracking On A Graphics Processing Unit, Michael A. Tanner

Theses and Dissertations

Multiple-target tracking (MTT) systems have been implemented on many different platforms, however these solutions are often expensive and have long development times. Such MTT implementations require custom hardware, yet offer very little flexibility with ever changing data sets and target tracking requirements. This research explores how to supplement and enhance MTT performance with an existing graphics processing unit (GPU) on a general computing platform. Typical computers are already equipped with powerful GPUs to support various games and multimedia applications. However, such GPUs are not currently being used in desktop MTT applications. This research explores if and how a GPU can …


The Modular Clock Algorithm For Blind Rendezvous, Nicholas C. Theis Mar 2009

The Modular Clock Algorithm For Blind Rendezvous, Nicholas C. Theis

Theses and Dissertations

This thesis examines the problem in initializing communications whereby cognitive radios need to find common spectrum with other cognitive radios, a process known as frequency rendezvous. It examines the rendezvous problem as it exists in a dynamic spectrum access cognitive network. Specifically, it addresses the problem of rendezvous in an infrastructureless environment. A new algorithm, the modular clock algorithm, is developed and analyzed as a solution for the simple rendezvous environment model, coupled with a modified version for environment models with less information. The thesis includes a taxonomy of commonly used environment models, and analysis of previous efforts to solve …


Numerical Analysis For Relevant Features In Intrusion Detection (Narfid), Jose Andres Gonzalez Mar 2009

Numerical Analysis For Relevant Features In Intrusion Detection (Narfid), Jose Andres Gonzalez

Theses and Dissertations

Identification of cyber attacks and network services is a robust field of study in the machine learning community. Less effort has been focused on understanding the domain space of real network data in identifying important features for cyber attack and network service classification. Motivations for such work allow for anomaly detection systems with less requirements on data “sniffed” off the network, extraction of features from the traffic, reduced learning time of algorithms, and ideally increased classification performance of anomalous behavior. This thesis evaluates the usefulness of a good feature subset for the general classification task of identifying cyber attacks and …


Automated Virtual Machine Introspection For Host-Based Intrusion Detection, Brett A. Pagel Feb 2009

Automated Virtual Machine Introspection For Host-Based Intrusion Detection, Brett A. Pagel

Theses and Dissertations

This thesis examines techniques to automate configuration of an intrusion detection system utilizing hardware-assisted virtualization. These techniques are used to detect the version of a running guest operating system, automatically configure version-specific operating system information needed by the introspection library, and to locate and monitor important operating system data structures. This research simplifies introspection library configuration and is a step toward operating system independent introspection. An operating system detection algorithm and Windows virtual machine system service dispatch table monitor are implemented using the Xen hypervisor and a modified version of the XenAccess library. All detection and monitoring is implemented from …


Adaptive Control Of Woofer-Tweeter Adaptive Optics, Jimmie J. Perez Feb 2009

Adaptive Control Of Woofer-Tweeter Adaptive Optics, Jimmie J. Perez

Theses and Dissertations

Adaptive optics applies advanced sensing and control to improve the ability of optical systems to collect images through a turbulent atmosphere. The results of this research effort demonstrate that the combination of two recent approaches improves the performance of adaptive optics in directed energy and laser communication scenarios. The first approach is adaptive control, which offers improved performance over fixed-gain controllers in the presence of rapidly changing turbulence. The second approach incorporated into the study is a dual-mirror system. The two mirrors are a high-bandwidth, low-actuator-stroke (tweeter) mirror and a low-bandwidth, large actuator-stroke (woofer) mirror. The woofer-tweeter combination allows for …


An Fpga-Based System For Tracking Digital Information Transmitted Via Peer-To-Peer Protocols, Karl R. Schrader Feb 2009

An Fpga-Based System For Tracking Digital Information Transmitted Via Peer-To-Peer Protocols, Karl R. Schrader

Theses and Dissertations

This thesis addresses the problem of identifying and tracking digital information that is shared using peer-to-peer file transfer and Voice over IP (VoIP) protocols. The goal of the research is to develop a system for detecting and tracking the illicit dissemination of sensitive government information using file sharing applications within a target network, and tracking terrorist cells or criminal organizations that are covertly communicating using VoIP applications. A digital forensic tool is developed using an FPGA-based embedded software application. The tool is designed to process file transfers using the BitTorrent peer-to-peer protocol and VoIP phone calls made using the Session …