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Theses and Dissertations

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Articles 2131 - 2160 of 2733

Full-Text Articles in Computer Sciences

Explicit Building Block Multiobjective Evolutionary Computation: Methods And Applications, Richard O. Day Jun 2005

Explicit Building Block Multiobjective Evolutionary Computation: Methods And Applications, Richard O. Day

Theses and Dissertations

This dissertation presents principles, techniques, and performance of evolutionary computation optimization methods. Concentration is on concepts, design formulation, and prescription for multiobjective problem solving and explicit building block (BB) multiobjective evolutionary algorithms (MOEAs). Current state-of-the-art explicit BB MOEAs are addressed in the innovative design, execution, and testing of a new multiobjective explicit BB MOEA. Evolutionary computation concepts examined are algorithm convergence, population diversity and sizing, genotype and phenotype partitioning, archiving, BB concepts, parallel evolutionary algorithm (EA) models, robustness, visualization of evolutionary process, and performance in terms of effectiveness and efficiency. The main result of this research is the development of …

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The Analysis Of A Link Between A Remote Local Area Network And Its Server Resources, Theresa D. Beaver Jun 2005

The Analysis Of A Link Between A Remote Local Area Network And Its Server Resources, Theresa D. Beaver

Theses and Dissertations

As the Air Force transitions to an expeditionary force, the service's ability to provide computer capabilities at remote locations becomes more and more paramount. One way to provide this support is to create a Local Area Network (LAN) in which the workstations are positioned at the deployed location while the servers are maintained at a Main Operating Base (MOB). This saves the military money, because it eliminates the need to purchase and deploy server equipment as well as eliminating the need to deploy personnel to set-up and maintain the servers. There is, however, a tradeoff. As the number of personnel …

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A Framework For Routing And Topological Decision-Making Within A Transformational Communications Architecture, Alexander I. Smith Jun 2005

A Framework For Routing And Topological Decision-Making Within A Transformational Communications Architecture, Alexander I. Smith

Theses and Dissertations

A Transformational Communications Architecture (TCA) has been proposed by the US government with the goal of creating "an Internet in the sky." This thesis presents a framework which places user requirements at the heart of routing and topological decision-making within the TCA. It provides new terminology to describe data transmissions and link characteristics and an approach to formulating cost functions to better meet user needs. The framework is intended to stimulate interest and focus efforts on how to meet military specific requirements by taking advantage of the TCA's diverse capabilities and topology. Cost functions using newly-defined parameters are simulated and …

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Phishing Warden: Enhancing Content-Triggered Trust Negotiation To Prevent Phishing Attacks, James Presley Henshaw Jun 2005

Phishing Warden: Enhancing Content-Triggered Trust Negotiation To Prevent Phishing Attacks, James Presley Henshaw

Theses and Dissertations

Phishing attacks are spam e-mails that attempt to fool recipients into divulging their identifying information by posing as a message from a well known company and using that company's branding and logos. It is estimated that phishing attacks have cost bank and credit card customers $1.2 billion in the U.S. in 2003. Previous work, content-triggered trust negotiation (CTTN), filters Internet traffic for sensitive data, and prevents a user from disclosing sensitive information to an un-trusted server. However, existing CTTN implementations are vulnerable to client-side scripts that obfuscate any data the client's browser sends to the web server in order to …

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Mindshare: A Collaborative Peer-To-Peer System For Small Groups, Gareth Charles Farrington May 2005

Mindshare: A Collaborative Peer-To-Peer System For Small Groups, Gareth Charles Farrington

Theses and Dissertations

We present Mindshare, a system for small group collaboration using Peer to Peer networking technology. This paper details the motivation behind its design, how it benefits users and details of its construction and operation. The solution focuses on the needs of small collaborating groups with limited computing experience and resources. Mindshare allows the group to share an unlimited number of files and visualize them in unified hierarchical file system. Mindshare synchronizes the files between users without user input. Its robust design allows files to be shared even when the owner is offline and allows users to work with files from …

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Learning Implicit User Interest Hierarchy For Web Personalization, Hyoung-Rae Kim May 2005

Learning Implicit User Interest Hierarchy For Web Personalization, Hyoung-Rae Kim

Theses and Dissertations

Most web search engines are designed to serve all users in a general way, without considering the interests of individual users. In contrast, personalized web search engines incorporate an individual user's interests when choosing relevant web pages to return. In order to provide a more robust context for personalization, a user interest hierarchy (UIH) is presented. The UIH extracts a continuum of general to specific user interests from web pages and generates a uniquely personalized order to search results. This dissertation consists of five main parts. First, a divisive hierarchical clustering (DHC) algorithm is proposed to group words (topics) into …

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Improving And Extending Behavioral Animation Through Machine Learning, Jonathan J. Dinerstein Apr 2005

Improving And Extending Behavioral Animation Through Machine Learning, Jonathan J. Dinerstein

Theses and Dissertations

Behavioral animation has become popular for creating virtual characters that are autonomous agents and thus self-animating. This is useful for lessening the workload of human animators, populating virtual environments with interactive agents, etc. Unfortunately, current behavioral animation techniques suffer from three key problems: (1) deliberative behavioral models (i.e., cognitive models) are slow to execute; (2) interactive virtual characters cannot adapt online due to interaction with a human user; (3) programming of behavioral models is a difficult and time-intensive process. This dissertation presents a collection of papers that seek to overcome each of these problems. Specifically, these issues are alleviated …

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Interactive Image Filling-In, Teryl Lynne Arnold Apr 2005

Interactive Image Filling-In, Teryl Lynne Arnold

Theses and Dissertations

Removing unwanted scratches or objects from an image in an undetectable manner is a technique that has been researched for its many useful and varied applications, such as removing scratches, defects, super-imposed text, or even entire objects from a scene. Currently there is a wide variety of algorithms that fill in unwanted regions, none of which incorporate user preferences into the structure completion process. By building a framework to incorporate user preferences into the filling-in process, user input can be utilized to more effectively fill in damaged regions in an image. User input can influence the filling-in process in a …

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T-Spline Merging, Heather Ipson Apr 2005

T-Spline Merging, Heather Ipson

Theses and Dissertations

Geometric models, such as for use in CAD/CAM or animation, are often constructed in a piece-wise fashion. Historically, these models have been made of NURBS surfaces. For various reasons it is problematic and often times mathematically impossible to combine several NURBS models into one continuous surface. The recent invention of a surface type called T-splines has made the combining of NURBS surfaces into a single continuous surface possible, but much of the mathematics has yet to be explored. This thesis explores the mathematics and algorithms necessary to merge multiple NURBS, T-spline, or T-NURCC surfaces into a single continuous surface. This …

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January: Search Based On Social Insect Behavior, Peter C. Lamborn Apr 2005

January: Search Based On Social Insect Behavior, Peter C. Lamborn

Theses and Dissertations

January is a group of interacting stateless model checkers. Each agent functions on a processor located on a super computer or a network of workstations (NOW). The agent's search pattern is a semi-random walk based on the behavior of the grey field slug (Agriolimax reticulatus), the house fly (Musca domestica), and the black ant (Lassius niger). The agents communicate to lessen the amount of duplicate work being done. Every algorithm has a memory threshold above which they search efficiently. This threshold varies not only by model but also by algorithm. Janaury's threshold is lower than the thresholds of other algorithms …

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Improving Routing Security Using A Decentralized Public Key Distribution Algorithm, Jeremy C. Goold Apr 2005

Improving Routing Security Using A Decentralized Public Key Distribution Algorithm, Jeremy C. Goold

Theses and Dissertations

Today's society has developed a reliance on networking infrastructures. Health, financial, and many other institutions deploy mission critical and even life critical applications on local networks and the global Internet. The security of this infrastructure has been called into question over the last decade. In particular, the protocols directing traffic through the network have been found to be vulnerable. One such protocol is the Open Shortest Path First (OSPF) protocol. This thesis proposes a security extension to OSPF containing a decentralized certificate authentication scheme (DecentCA) that eliminates the single point of failure/attack present in current OSPF security extensions. An analysis …

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Keyword Spotting Using Normalization Of Posterior Probability Confidence Measures, Rachna Vijay Vargiya Apr 2005

Keyword Spotting Using Normalization Of Posterior Probability Confidence Measures, Rachna Vijay Vargiya

Theses and Dissertations

Keyword spotting techniques deal with recognition of predefined vocabulary keywords from a voice stream. This research uses HMM based keyword spotting algorithms for this purpose. The three most important components of a keyword detection system are confidence measure, pruning technique and evaluation of results. We suggest that best match for a keyword would be an alignment in which all constituent states have high emission probabilities. Therefore score of even the worst subsequence must also be better than a threshold and a path can be represented by the score of its worst subsequence match. This confidence measure is called Real Fitting. …

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A Statistical Performance Model Of Homogeneous Raidb Clusters, Brandon Lamar Rogers Mar 2005

A Statistical Performance Model Of Homogeneous Raidb Clusters, Brandon Lamar Rogers

Theses and Dissertations

The continual growth of the Internet and e-commerce is driving demand for speed, reliability and processing power. With the rapid development and maturation of e-commerce, the need for a quick access to large amounts of information is steadily rising. Traditionally, database systems have been used for information storage and retrieval. However, with online auctions, rapid Internet searches, and data archival, the need for more powerful database systems is also growing. One type of distributed database is called Redundant Arrays of Inexpensive Databases (RAIDb). RAIDb clusters are middleware-driven to promote interoperability and portability. RAIDb clusters allow for multiple levels of data …

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Thor: The Hybrid Online Repository, Timothy W. Van Der Horst Mar 2005

Thor: The Hybrid Online Repository, Timothy W. Van Der Horst

Theses and Dissertations

Digital credentials enable users to perform secure interactions by proving either their identity or that they posses certain attributes. Special care is taken to protect these credentials and their associated private keys during transaction time. However, protection of these items outside of the transaction is often delegated to a secure credential repository. A mobile environment creates significant challenges for secure repositories. We examine these challenges with respect to existing repository practices and produce a set of requirements that a repository must meet in order to cope with the harshness of a mobile environment. We also present the design and implementation …

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Web Usability Guidelines For Air Force Knowledge Now Web Site, Gary A. Felax Mar 2005

Web Usability Guidelines For Air Force Knowledge Now Web Site, Gary A. Felax

Theses and Dissertations

The Department of Defense Net-Centric Data Strategies number one key attribute is to ensure data is visible, available, and usable when and where needed to accelerate decision-making. The Internet provides opportunities for quick and efficient disseminating of information to the public, distributing information throughout the Air Force, and accessing information from a variety of sources. In 2002, the Air Force CIO designated the Air Force Knowledge Now (AFKN) as the center of excellence for Knowledge Management. The site is a one-stop resource, providing access to a great depth and breadth of information. This study seeks to determine how usable and …

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Assessing The Usefulness Of Visualization Tools To Investigate Hidden Patterns With Insider Attack Cases, Amy M. Rammel Mar 2005

Assessing The Usefulness Of Visualization Tools To Investigate Hidden Patterns With Insider Attack Cases, Amy M. Rammel

Theses and Dissertations

The insider threat is a major concern for organizations. Open markets, technological advances, and the evolving definition of employee have exacerbated the insider threat. Insider threat research efforts are focusing on both prevention and detection techniques. However, recent security violation trends highlight the damage insider attacks cause organizations and illuminate why organizations and researchers must develop new approaches to this challenge. Although fruitful research is being conducted and new technologies are being applied to the insider threat problem, companies remain susceptible to the costly damage generated by insider threat actions. This research explored how visualization tools may be useful in …

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Passwords: A Survey On Usage And Policy, Kurt W. Martinson Mar 2005

Passwords: A Survey On Usage And Policy, Kurt W. Martinson

Theses and Dissertations

Computer password use is on the rise. Passwords have become one of the primary authentication methods used today. It is because of their high use that organizations have started to place parameters on passwords. Are password restrictions a nuisance? What are some of the consequences that result as organizations place the burden of their computer security on passwords? This thesis analyzes the results of a survey instrument that was used to determine if individuals are using similar techniques or patterns when choosing or remembering their passwords. It also looks at how individuals feel about using passwords. In addition, the authors …

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Assessing Information Trustability In A Secure Web Services Environment, Charles G. Penner Mar 2005

Assessing Information Trustability In A Secure Web Services Environment, Charles G. Penner

Theses and Dissertations

Decisions are made based on available information. A decision support system endeavors to provide information that is timely, accurate, and trustable. Information gathered from secure web service transactions has attributes that can be used to assess a level of trustability. The trust assessments enable a decision maker to determine a basis for confidence in the information presented from the web service. Existing trust assessment models do not provide a way to determine from a particular trust assessment what information attributes contributed to its computation. The present work creates trust values that retain and denote meaning, allowing a decision maker to …

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A Three Dimensional Helmet Mounted Primary Flight Reference For Paratroopers, Jason I. Thompson Mar 2005

A Three Dimensional Helmet Mounted Primary Flight Reference For Paratroopers, Jason I. Thompson

Theses and Dissertations

This thesis seeks to develop a Heads Up Display (HUD) presented on a Helmet Mounted Display (HMD), which presents a three-dimensional, graphical, predictive navigational reference to a paratrooper during a High Altitude, High Opening (HAHO) parachute jump. A Path Generating Algorithm (PGA) takes as input the Landing Zone's (LZ) location, the wind profile, and the paratrooper's parachute's performance characteristics, and returns a set of waypoints for the paratrooper to follow. The PGA attempts to maximize the distance that the paratrooper travels. The PGA's output is used to build a path to the LZ from a Release Point (RP). During the …

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An Evolutionary Algorithm To Generate Ellipsoid Detectors For Negative Selection, Joseph M. Shapiro Mar 2005

An Evolutionary Algorithm To Generate Ellipsoid Detectors For Negative Selection, Joseph M. Shapiro

Theses and Dissertations

Negative selection is a process from the biological immune system that can be applied to two-class (self and nonself) classification problems. Negative selection uses only one class (self) for training, which results in detectors for the other class (nonself). This paradigm is especially useful for problems in which only one class is available for training, such as network intrusion detection. Previous work has investigated hyper-rectangles and hyper-spheres as geometric detectors. This work proposes ellipsoids as geometric detectors. First, the author establishes a mathematical model for ellipsoids. He develops an algorithm to generate ellipsoids by training on only one class of …

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Robot Mapping With Real-Time Incremental Localization Using Expectation Maximization, Kevin L. Owens Mar 2005

Robot Mapping With Real-Time Incremental Localization Using Expectation Maximization, Kevin L. Owens

Theses and Dissertations

This research effort explores and develops a real-time sonar-based robot mapping and localization algorithm that provides pose correction within the context of a single room, to be combined with pre-existing global localization techniques, and thus produce a single, well-formed map of an unknown environment. Our algorithm implements an expectation maximization algorithm that is based on the notion of the alpha-beta functions of a Hidden Markov Model. It performs a forward alpha calculation as an integral component of the occupancy grid mapping procedure using local maps in place of a single global map, and a backward beta calculation that considers the …

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Determination Of Structure From Motion Using Aerial Imagery, Paul R. Graham Mar 2005

Determination Of Structure From Motion Using Aerial Imagery, Paul R. Graham

Theses and Dissertations

The structure from motion process creates three-dimensional models from a sequence of images. Until recently, most research in this field has been restricted to land-based imagery. This research examines the current methods of land-based structure from motion and evaluates their performance for aerial imagery. Current structure from motion algorithms search the initial image for features to track though the subsequent images. These features are used to create point correspondences between the two images. The correspondences are used to estimate the motion of the camera and then the three-dimensional structure of the scene. This research tests current algorithms using synthetic data …

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Analysis Of Effects Of Bgp Black Hole Routing On A Network Like The Niprnet, Michael D. Kleffman Mar 2005

Analysis Of Effects Of Bgp Black Hole Routing On A Network Like The Niprnet, Michael D. Kleffman

Theses and Dissertations

The Department of Defense (DoD) relies heavily on the Non-secure Internet Protocol Router Network (NIPRNET) to exchange information freely between departments, services, bases, posts, and ships. The NIPRNET is vulnerable to various attacks, to include physical and cyber attacks. One of the most frequently used cyber attacks by criminally motivated hackers is a Distributed Denial of Service (DDoS) attack. DDoS attacks can be used to exhaust network bandwidth and router processing capabilities, and as a leveraging tool for extortion. Border Gateway Protocol (BGP) black hole routing is a responsive defensive network technique for mitigating DDoS attacks. BGP black hole routing …

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An Analysis Of Perturbed Quantization Steganography In The Spatial Domain, Matthew D. Spisak Mar 2005

An Analysis Of Perturbed Quantization Steganography In The Spatial Domain, Matthew D. Spisak

Theses and Dissertations

Steganography is a form of secret communication in which a message is hidden into a harmless cover object, concealing the actual existence of the message. Due to the potential abuse by criminals and terrorists, much research has also gone into the field of steganalysis - the art of detecting and deciphering a hidden message. As many novel steganographic hiding algorithms become publicly known, researchers exploit these methods by finding statistical irregularities between clean digital images and images containing hidden data. This creates an on-going race between the two fields and requires constant countermeasures on the part of steganographers in order …

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Accelerating Missile Threat Engagement Simulations Using Personal Computer Graphics Cards, Sean E. Jeffers Mar 2005

Accelerating Missile Threat Engagement Simulations Using Personal Computer Graphics Cards, Sean E. Jeffers

Theses and Dissertations

The 453rd Electronic Warfare Squadron supports on-going military operations by providing battlefield commanders with aircraft ingress and egress routes that minimize the risk of shoulder or ground-fired missile attacks on our aircraft. To determine these routes, the 453rd simulates engagements between ground-to-air missiles and allied aircraft to determine the probability of a successful attack. The simulations are computationally expensive, often requiring two-hours for a single 10-second missile engagement. Hundreds of simulations are needed to perform a complete risk assessment which includes evaluating the effectiveness of countermeasures such as flares, chaff, jammers, and missile warning systems. Thus, the need for faster …

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A Genetic Algorithm For Uav Routing Integrated With A Parallel Swarm Simulation, Matthew A. Russell Mar 2005

A Genetic Algorithm For Uav Routing Integrated With A Parallel Swarm Simulation, Matthew A. Russell

Theses and Dissertations

This research investigation addresses the problem of routing and simulating swarms of UAVs. Sorties are modeled as instantiations of the NP-Complete Vehicle Routing Problem, and this work uses genetic algorithms (GAs) to provide a fast and robust algorithm for a priori and dynamic routing applications. Swarms of UAVs are modeled based on extensions of Reynolds' swarm research and are simulated on a Beowulf cluster as a parallel computing application using the Synchronous Environment for Emulation and Discrete Event Simulation (SPEEDES). In a test suite, standard measures such as benchmark problems, best published results, and parallel metrics are used as performance …

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National Security Agency (Nsa) Systems And Network Attack Center (Snac) Security Guides Versus Known Worms, Matthew W. Sullivan Mar 2005

National Security Agency (Nsa) Systems And Network Attack Center (Snac) Security Guides Versus Known Worms, Matthew W. Sullivan

Theses and Dissertations

Internet worms impact Internet security around the world even though there are many defenses to prevent the damage they inflict. The National Security Agency (NSA) Systems and Network Attack Center (SNAC) publishes in-depth configuration guides to protect networks from intrusion; however, the effectiveness of these guides in preventing the spread of worms hasn't been studied. This thesis establishes how well the NSA SNAC guides protect against various worms and exploits compared to Microsoft patches alone. It also identifies the aspects of the configuration guidance that is most effective in the absence of patches and updates, against network worm and e-mail …

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An Analysis Of Biometric Technology As An Enabler To Information Assurance, Darren A. Deschaine Mar 2005

An Analysis Of Biometric Technology As An Enabler To Information Assurance, Darren A. Deschaine

Theses and Dissertations

The use of and dependence on, Information technology (IT) has grown tremendously in the last two decades. Still, some believe the United States is only in the infancy of this growth. This explosive growth has opened the door to capabilities that were only dreamed of in the past. As easy as it is to see how advantageous this technology is, it also is clear that with its advantages come distinct responsibilities and new problems that must be addressed. For instance, the minute one begins using information processing systems, the world of information assurance (IA) becomes far more complex. As a …

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Modeling Information Quality Expectation In Unmanned Aerial Vehicle Swarm Sensor Databases, Patrick D. Baldwin Mar 2005

Modeling Information Quality Expectation In Unmanned Aerial Vehicle Swarm Sensor Databases, Patrick D. Baldwin

Theses and Dissertations

Swarming Unmanned Aerial Vehicles (UAVs) are the future of Intelligence, Surveillance and Reconnaissance (ISR). Swarms of hundreds of these vehicles, each equipped with multiple sensors, will one day fill the skies over hostile areas. As the sensors collect hundreds of gigabytes of data, telemetry data links will be unable to transmit the complete data picture to the ground in real time. The collected data will be stored on board the UAVs and selectively downloaded through queries issued from analysts on the ground. Analysts expect to find relevant sensor data within the collection of acquired sensor data. This expectation is not …

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Real-Time Mapping Using Stereoscopic Vision Optimization, Kevin M. Biggs Mar 2005

Real-Time Mapping Using Stereoscopic Vision Optimization, Kevin M. Biggs

Theses and Dissertations

This research focuses on efficient methods of generating 2D maps from stereo vision in real-time. Instead of attempting to locate edges between objects, we make the assumption that the representative surfaces of objects in a view provide enough information to generate a map while taking less time to locate during processing. Since all real-time vision processing endeavors are extremely computationally intensive, numerous optimization techniques are applied to allow for a real-time application: horizontal spike smoothing for post-disparity noise, masks to focus on close-proximity objects, melding for object synthesis, and rectangular fitting for object extraction under a planar assumption. Additionally, traditional …

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