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Theses and Dissertations

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Articles 1981 - 2010 of 2733

Full-Text Articles in Computer Sciences

Or Best Offer: A Privacy Policy Negotiation Protocol, Daniel David Walker Jul 2007

Or Best Offer: A Privacy Policy Negotiation Protocol, Daniel David Walker

Theses and Dissertations

Users today are concerned about how their information is collected, stored and used by Internet sites. Privacy policy languages, such as the Platform for Privacy Preferences (P3P), allow websites to publish their privacy practices and policies in machine readable form. Currently, software agents designed to protect users' privacy follow a "take it or leave it" approach when evaluating these privacy policies. This approach is inflexible and gives the server ultimate control over the privacy of web transactions. Privacy policy negotiation is one approach to leveling the playing field by allowing a client to negotiate with a server to determine how …

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Extensible Pre-Authentication In Kerberos, Phillip L. Hellewell Jul 2007

Extensible Pre-Authentication In Kerberos, Phillip L. Hellewell

Theses and Dissertations

Organizations need to provide services to a wide range of people, including strangers outside their local security domain. As the number of users grows larger, it becomes increasingly tedious to maintain and provision user accounts. It remains an open problem to create a system for provisioning outsiders that is secure, flexible, efficient, scalable, and easy to manage. Kerberos is a secure, industry-standard protocol. Currently, Kerberos operates as a closed system; all users must be specified upfront and managed on an individual basis. This paper presents EPAK (Extensible Pre-Authentication in Kerberos), a framework that enables Kerberos to operate as an open …

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Obstacle Avoidance And Path Traversal Using Interactive Machine Learning, Jonathan M. Turner Jul 2007

Obstacle Avoidance And Path Traversal Using Interactive Machine Learning, Jonathan M. Turner

Theses and Dissertations

Recently there has been a growing interest in using robots in activities that are dangerous or cost prohibitive for humans to do. Such activities include military uses and space exploration. While robotic hardware is often capable of being used in these types of situations, the ability of human operators to control robots in an effective manner is often limited. This deficiency is often related to the control interface of the robot and the level of autonomy that control system affords the human operator. This thesis describes a robot control system, called the safe/unsafe system, which gives a human operator the …

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Conceptual Xml For Systems Analysis, Reema Al-Kamha Jun 2007

Conceptual Xml For Systems Analysis, Reema Al-Kamha

Theses and Dissertations

Because XML has become a new standard for data representation, there is a need for a simple conceptual model that works well with XML-based development. In this research we present a conceptual model for XML, called C-XML, which meets this new need of systems analysts who store their data using XML. We describe our implementation of an automatic conversion from XML Schema to C-XML that preserves information and constraints. With this conversion, we can view an XML Schema instance graphically at a higher level of abstraction. We also describe our implementation of an automatic conversion from C-XML to XML Schema. …

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Efficient Gps Position Determination Algorithms, Thao Nguyen Jun 2007

Efficient Gps Position Determination Algorithms, Thao Nguyen

Theses and Dissertations

This research is aimed at improving the state of the art of GPS algorithms, namely, the development of a closed-form positioning algorithm for a standalone user and the development of a novel differential GPS algorithm for a network of users. The stand-alone user GPS algorithm is a direct, closed-form, and efficient new position determination algorithm that exploits the closed-form solution of the GPS trilateration equations and works in the presence of pseudorange measurement noise for an arbitrary number of satellites in view. A two-step GPS position determination algorithm is derived which entails the solution of a linear regression and updates …

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Intelligent Rotoscoping: A Semi-Automated Interactive Boundary Tracking Approach To Video Segmentation, Seth R. Holladay Jun 2007

Intelligent Rotoscoping: A Semi-Automated Interactive Boundary Tracking Approach To Video Segmentation, Seth R. Holladay

Theses and Dissertations

Video segmentation is an application of computer vision aimed at automating the extraction of an object from a series of video frames. However, it is a difficult problem, especially to compute at real-time, interactive rates. Although general application to video is difficult because of the wide range of image scenarios, user interaction can help to reduce the problem space and speed up the computation. This thesis presents a fast object-tracking tool that selects an object from a series of frames based on minimal user input. Our Intelligent Rotoscoping tool aims for increased speed and accuracy over other video segmentation tools, …

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Finding Termination And Time Improvement In Predicate Abstraction With Under-Approximation And Abstract Matching, Dritan Kudra Jun 2007

Finding Termination And Time Improvement In Predicate Abstraction With Under-Approximation And Abstract Matching, Dritan Kudra

Theses and Dissertations

The focus of current formal verification methods is mitigating the state explosion problem. One of these formal methods is predicate abstraction, which reduces concrete states of a system to bitvectors of true/false valuations of a set of predicates. Predicate abstraction comes in two flavors, over-approximation and under-approximation. A drawback of over-approximation is that it produces too many spurious errors for data-intensive applications. A more recent under-approximation technique which does not produce spurious errors, does abstract matching on concrete states (AMCS). AMCS adds behaviors to an abstract system by augmenting the set of initial predicates, making use of a theorem prover. …

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Cognitive And Behavioral Model Ensembles For Autonomous Virtual Characters, Jeffrey S. Whiting Jun 2007

Cognitive And Behavioral Model Ensembles For Autonomous Virtual Characters, Jeffrey S. Whiting

Theses and Dissertations

Cognitive and behavioral models have become popular methods to create autonomous self-animating characters. Creating these models presents the following challenges: (1) Creating a cognitive or behavioral model is a time intensive and complex process that must be done by an expert programmer (2) The models are created to solve a specific problem in a given environment and because of their specific nature cannot be easily reused. Combining existing models together would allow an animator, without the need of a programmer, to create new characters in less time and would be able to leverage each model's strengths to increase the character's …

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Vision-Based Control And Flight Optimization Of A Rotorcraft Uav, David Christian Hubbard Jun 2007

Vision-Based Control And Flight Optimization Of A Rotorcraft Uav, David Christian Hubbard

Theses and Dissertations

A Rotorcraft UAV provides an ideal experimental platform for vision-based navigation. This thesis describes the flight tests of the US Army PALACE pro ject, which implements Moravec's pseudo-normalized correlation tracking algorithm. The tracker uses the movement of the landing site in the camera, a laser range, and the aircraft attitude from an IMU to estimate the relative motion of the UAV. The position estimate functions as a GPS equivalent to enable the rotorcraft to maneuver without the aid of GPS. Flight tests were performed with obstacles and over concrete, asphalt, and grass in daylight conditions with a safe landing area …

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Type Inference, Type Improvement, And Type Simplification In A Language With User-Defined Polymorphic Relational Operators, Lajos Pál Nagy May 2007

Type Inference, Type Improvement, And Type Simplification In A Language With User-Defined Polymorphic Relational Operators, Lajos Pál Nagy

Theses and Dissertations

The overarching goal of the current thesis is to pave the road towards a comprehensive solution to the decades old problem of integrating databases and programming languages. For this purpose, we propose a record calculus as an extension of an ML-style functional programming language core. In particular, we describe: 1. a set of polymorphic record operations that are expressive enough to define the operators of the relational algebra; 2. a type system together with a type inference algorithm, based on the theory of qualified types, to correctly capture the types of said polymorphic record operations; 3. an algorithm for checking …

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Manifold Sculpting, Michael S. Gashler Apr 2007

Manifold Sculpting, Michael S. Gashler

Theses and Dissertations

Manifold learning algorithms have been shown to be useful for many applications of numerical analysis. Unfortunately, existing algorithms often produce noisy results, do not scale well, and are unable to benefit from prior knowledge about the expected results. We propose a new algorithm that iteratively discovers manifolds by preserving the local structure among neighboring data points while scaling down the values in unwanted dimensions. This algorithm produces less noisy results than existing algorithms, and it scales better when the number of data points is much larger than the number of dimensions. Additionally, this algorithm is able to benefit from existing …

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Hop-By-Hop Transport Control For Multi-Hop Wireless Networks, Daniel N. Scofield Apr 2007

Hop-By-Hop Transport Control For Multi-Hop Wireless Networks, Daniel N. Scofield

Theses and Dissertations

TCP can perform poorly in multi-hop wireless networks due to problems with contention and poor feedback from end-to-end control algorithms. This thesis explores the design of a hop-by-hop transport protocol (HxH). By allowing intermediate nodes to actively participate, the protocol can respond more quickly to changing network conditions and exploit the unique characteristics of wireless networks. Results indicate that hop-by-hop transport can achieve throughput rates that are double those of TCP, depending on the speed of the wireless links.

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T-Spline Simplification, David L. Cardon Apr 2007

T-Spline Simplification, David L. Cardon

Theses and Dissertations

This work focuses on generating approximations of complex T-spline surfaces with similar but less complex T-splines. Two approaches to simplifying T-splines are proposed: a bottom-up approach that iteratively refines an over-simple T-spline to approximate a complex one, and a top-down approach that evaluates existing control points for removal in producing an approximations. This thesis develops and compares the two simplification methods, determining the simplification tasks to which each is best suited. In addition, this thesis documents supporting developments made to T-spline research as simplification was developed.

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In Pursuit Of An Aptitude Test For Potential Cyberspace Warriors, Tiffiny S. Smith Mar 2007

In Pursuit Of An Aptitude Test For Potential Cyberspace Warriors, Tiffiny S. Smith

Theses and Dissertations

The Air Force has officially assumed the cyberspace mission. To perform this mission well, it is important to employ personnel who have the necessary skill sets and motivation to work in a cyberspace environment. The first step in employing the right people is to screen all possible candidates and select those with an aptitude for acquiring the skill sets and with the motivation to perform this work. This thesis attempts to determine the necessary skills and motivations to perform the cyberspace mission and recommends a screening process to select the candidates with the highest probability for success. Since this mission …

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On-The-Fly Dynamic Dead Variable Analysis, Joel P. Self Mar 2007

On-The-Fly Dynamic Dead Variable Analysis, Joel P. Self

Theses and Dissertations

State explosion in model checking continues to be the primary obstacle to widespread use of software model checking. The large input ranges of variables used in software is the main cause of state explosion. As software grows in size and complexity the problem only becomes worse. As such, model checking research into data abstraction as a way of mitigating state explosion has become more and more important. Data abstractions aim to reduce the effect of large input ranges. This work focuses on a static program analysis technique called dead variable analysis. The goal of dead variable analysis is to discover …

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Internet Protocol Geolocation: Development Of A Delay-Based Hybrid Methodology For Locating The Geographic Location Of A Network Node, John M. Roehl Mar 2007

Internet Protocol Geolocation: Development Of A Delay-Based Hybrid Methodology For Locating The Geographic Location Of A Network Node, John M. Roehl

Theses and Dissertations

Internet Protocol Geolocation (IP Geolocation), the process of determining the approximate geographic location of an IP addressable node, has proven useful in a wide variety of commercial applications. Commercial applications of IP Geolocation include market research, redirection for performance enhancement, restricting content, and combating fraud. The potential for military applications include securing remote access via geographic authentication, intelligence collection, and cyber attack attribution. IP Geolocation methods can be divided into three basic categories based upon what information is used to determine the geographic location of the given IP address: 1) Information contained in databases, 2) information that is leaked during …

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Wide Area Search And Engagement Simulation Validation, Michael J. Marlin Mar 2007

Wide Area Search And Engagement Simulation Validation, Michael J. Marlin

Theses and Dissertations

As unmanned aerial vehicles (UAVs) increase in capability, the ability to refuel them in the air is becoming more critical. Aerial refueling will extend the range, shorten the response times, and extend loiter time of UAVs. Executing aerial refueling autonomously will reduce the command and control, logistics, and training efforts associated with fielding UAV systems. Currently, the Air Force Research Lab is researching the various technologies required to conduct automated aerial refueling (AAR). One of the required technologies is the ability to autonomously rendezvous with the tanker. The goal of this research is to determine the control required to fly …

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Geospatial Informational Security Risks And Concerns Of The U.S. Air Force Geobase Program, Scott A. Bryant Mar 2007

Geospatial Informational Security Risks And Concerns Of The U.S. Air Force Geobase Program, Scott A. Bryant

Theses and Dissertations

Technological advancements such as Geospatial Information Systems (GIS) and the Internet have made it easier and affordable to share information, which enables complex and time sensitive decisions to be made with higher confidence. Further, advancements in information technology have dramatically increased the ability to store, manage, integrate, and correlate larger amounts of data to improve operational efficiency. However, the same technologies that enable increased productivity also provide increased capabilities to those wishing to do harm. Today’s military leaders are faced with the challenge of deciding how to make geospatial information collected on military installations and organizations available to authorized communities …

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Adaptive Gravitational Gossip In Monitoring The Joint Battlespace Infosphere, Edmund Descartes Aban Mar 2007

Adaptive Gravitational Gossip In Monitoring The Joint Battlespace Infosphere, Edmund Descartes Aban

Theses and Dissertations

Future USAF operations will be heavily dependent on having the "right information" at the "right time," and Joint Battlespace Infospheres (JBIs) are poised to fill that role. To do this, JBIs must be ubiquitous -- always accessible, secure and responsive. Of all the literature written regarding JBIs, the most important problem to solve in order to make JBIs work in mobile scenarios are scalability, reliability and adaptability to changing battlefield conditions. This paper explores the use of SBCast, a novel adaptive probabilistic protocol and a delivery mechanism for JBI updates and as a possible solution towards guaranteeing these qualities. It …

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Use Of Tabu Search In A Solver To Map Complex Networks Onto Emulab Testbeds, Jason E. Macdonald Mar 2007

Use Of Tabu Search In A Solver To Map Complex Networks Onto Emulab Testbeds, Jason E. Macdonald

Theses and Dissertations

The University of Utah's solver for the testbed mapping problem uses a simulated annealing metaheuristic algorithm to map a researcher's experimental network topology onto available testbed resources. This research uses tabu search to find near-optimal physical topology solutions to user experiments consisting of scale-free complex networks. While simulated annealing arrives at solutions almost exclusively by chance, tabu search incorporates the use of memory and other techniques to guide the search towards good solutions. Both search algorithms are compared to determine whether tabu search can produce equal or higher quality solutions than simulated annealing in a shorter amount of time. It …

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Improving Machine Learning Through Oracle Learning, Joshua Ephraim Menke Mar 2007

Improving Machine Learning Through Oracle Learning, Joshua Ephraim Menke

Theses and Dissertations

The following dissertation presents a new paradigm for improving the training of machine learning algorithms, oracle learning. The main idea in oracle learning is that instead of training directly on a set of data, a learning model is trained to approximate a given oracle's behavior on a set of data. This can be beneficial in situations where it is easier to obtain an oracle than it is to use it at application time. It is shown that oracle learning can be applied to more effectively reduce the size of artificial neural networks, to more efficiently take advantage of domain experts …

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Obstacle Annotation By Demonstration, Michael David Clement Mar 2007

Obstacle Annotation By Demonstration, Michael David Clement

Theses and Dissertations

By observing human driving with a “digital head" (combined video camera and accelerometers) and taking a few hand annotations, we can automatically annotate regions in a robot's field of view that should be interpreted as obstacles to be avoided. This is accomplished by detecting the movement for a given frame in a video. Some hand annotations of video frames are necessary and they are used to create Probability Grids. Using the movement data and the Probability Grids, it is possible to annotate large amounts of video data quickly in an automated system.

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Observational Studies Of Software Engineering Using Data From Software Repositories, Daniel Pierce Delorey Mar 2007

Observational Studies Of Software Engineering Using Data From Software Repositories, Daniel Pierce Delorey

Theses and Dissertations

Data for empirical studies of software engineering can be difficult to obtain. Extrapolations from small controlled experiments to large development environments are tenuous and observation tends to change the behavior of the subjects. In this thesis we propose the use of data gathered from software repositories in observational studies of software engineering. We present tools we have developed to extract data from CVS repositories and the SourceForge Research Archive. We use these tools to gather data from 9,999 Open Source projects. By analyzing these data we are able to provide insights into the structure of Open Source projects. For example, …

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Hardware Virtualization Applied To Rootkit Defense, Douglas P. Medley Mar 2007

Hardware Virtualization Applied To Rootkit Defense, Douglas P. Medley

Theses and Dissertations

This research effort examines the idea of applying virtualization hardware to enhance operating system security against rootkits. Rootkits are sets of tools used to hide code and/or functionality from the user and operating system. Rootkits can accomplish this feat through using access to one part of an operating system to change another part that resides at the same privilege level. Hardware assisted virtualization (HAV) provides an opportunity to defeat this tactic through the introduction of a new operating mode. Created to aid operating system virtualization, HAV provides hardware support for managing and saving multiple states of the processor. This hardware …

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Implementation And Optimization Of The Advanced Encryption Standard Algorithm On An 8-Bit Field Programmable Gate Array Hardware Platform, Ryan J. Silva Mar 2007

Implementation And Optimization Of The Advanced Encryption Standard Algorithm On An 8-Bit Field Programmable Gate Array Hardware Platform, Ryan J. Silva

Theses and Dissertations

The contribution of this research is three-fold. The first is a method of converting the area occupied by a circuit implemented on a Field Programmable Gate Array (FPGA) to an equivalent as a measure of total gate count. This allows direct comparison between two FPGA implementations independent of the manufacturer or chip family. The second contribution improves the performance of the Advanced Encryption Standard (AES) on an 8-bit computing platform. This research develops an AES design that occupies less than three quarters of the area reported by the smallest design in current literature as well as significantly increases area efficiency. …

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Beyond Passswords: Usage And Policy Transformation, Alan S. Alsop Mar 2007

Beyond Passswords: Usage And Policy Transformation, Alan S. Alsop

Theses and Dissertations

The purpose of this research is to determine whether the transition to a two-factor authentication system is more secure than a system that relied only on what users “know” for authentication. While we found that factors that made passwords inherently vulnerable did not transfer to the PIN portion of a two-factor authentication system, we did find significant problems relating to usability, worker productivity, and the loss and theft of smart cards. The new authentication method has disrupted our ability to stay connected to ongoing mission issues, forced some installations to cut off remote access for their users and in one …

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Using Concept Maps To More Efficiently Create Intelligence Information Models, Christopher E. Coryell Mar 2007

Using Concept Maps To More Efficiently Create Intelligence Information Models, Christopher E. Coryell

Theses and Dissertations

Information models are a critical tool that enables intelligence customers to quickly and accurately comprehend U.S. intelligence agency products. The Knowledge Pre-positioning System (KPS) is the standard repository for information models at the National Air and Space Intelligence Center (NASIC). The current approach used by NASIC to build a KPS information model is laborious and costly. Intelligence analysts design an information model using a manual, butcher-paper-based process. The output of their work is then entered into KPS by either a single NASIC KPS "database modeler" or a contractor (at a cost of roughly $100K to the organization). This thesis proposes …

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Use Of Thrust Vectors In Support Of The Cybercraft Initiative, Michael Stevens Mar 2007

Use Of Thrust Vectors In Support Of The Cybercraft Initiative, Michael Stevens

Theses and Dissertations

The CyberCraft Initiative is designing a framework for command and control of future Air Force Cyber-weapon systems, that autonomously operate and defend the Air Force networks and information systems to provide Cyberspace Superiority in support of the defense of the United States. The fundamental research question of the CyberCraft Initiative is "What is required for a commander to trust a CyberCraft to autonomously defend military information systems?" The Trust Vector model is one method of integrating trust into the CyberCraft fleet. Trust Vectors define trust and distrust between agents based on three components; current and historical data, intrinsic knowledge of …

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Locating Encrypted Data Hidden Among Non-Encrypted Data Using Statistical Tools, Walter J. Hayden Mar 2007

Locating Encrypted Data Hidden Among Non-Encrypted Data Using Statistical Tools, Walter J. Hayden

Theses and Dissertations

This research tests the security of software protection techniques that use encryption to protect code segments containing critical algorithm implementation to prevent reverse engineering. Using the National Institute of Standards and Technology (NIST) Tests for Randomness encrypted regions hidden among non-encrypted bits of a binary executable file are located. The location of ciphertext from four encryption algorithms (AES, DES, RSA, and TEA) and three block sizes (10, 100, and 500 32-bit words) were tested during the development of the techniques described in this research. The test files were generated from the Win32 binary executable file of Adobe's Acrobat Reader version …

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Stylized Hatching For 3d Animation, Trent Fielding Crow Mar 2007

Stylized Hatching For 3d Animation, Trent Fielding Crow

Theses and Dissertations

Much research has been done in creating non-photorealistic renderings of objects that mimic the look of hand-made drawings by traditional artists. This thesis extends work in this area by presenting an NPR hatching method that can be applied to 3D animated films to help them feel more hand drawn. In contrast to most other NPR methods, this method preserves the 3D lighting and effects of the film that make it interesting to watch. This process includes a procedural algorithm to create a hatching pattern that can be easily integrated into any film's pipeline that uses Renderman. In addition, we create …

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