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2008

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Articles 751 - 780 of 1335

Full-Text Articles in Computer Sciences

A Formal Specification And Proof Of System Safety Using The Schematic Protection Model, Raymond S. Way Mar 2008

A Formal Specification And Proof Of System Safety Using The Schematic Protection Model, Raymond S. Way

Theses and Dissertations

This research formally specifies the Schematic Protection Model (SPM) and provides a sound, flexible tool for reasoning formally about systems that implement a security model like SPM, to prove its ability to provide security services such as confidentiality and integrity. The theory described by the resultant model was logically proved in the Prototype Verification System (PVS), an automated prover. Each component of SPM was tested, as were several anomalous conditions, and each test produced results consistent with the model. The model is internally modular, and therefore easily extensible, yet cohesive since the theory to be proved encompasses the entire specification. …

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A Bittorrent Proxy, Robert Brent Larsen Mar 2008

A Bittorrent Proxy, Robert Brent Larsen

Theses and Dissertations

BitTorrent is a peer-to-peer protocol useful for distributing large files over the Internet. Many organizations use BitTorrent to distribute their software in order to reduce client download time and reduce the load on their servers. While there is a lot of legitimate content available via BitTorrent, some organizations ban BitTorrent usage due to concerns over copyright infringement and the amount of bandwidth that peers can consume. A BitTorrent proxy will allow organizations to control those risks and allow its members to use the BitTorrent protocol for approved uses. It will allow the organization to control the files that are downloaded …

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Deriving Input Syntactic Structure From Execution And Its Applications, Zhiqiang Lin, Xiangyu Zhang Mar 2008

Deriving Input Syntactic Structure From Execution And Its Applications, Zhiqiang Lin, Xiangyu Zhang

Department of Computer Science Technical Reports

No abstract provided.

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Developing A Reference Framework For Cybercraft Trust Evaluation, Shannon E. Hunt Mar 2008

Developing A Reference Framework For Cybercraft Trust Evaluation, Shannon E. Hunt

Theses and Dissertations

It should be no surprise that Department of Defense (DoD) and U.S. Air Force (USAF) networks are the target of constant attack. As a result, network defense remains a high priority for cyber warriors. On the technical side, trust issues for a comprehensive end-to-end network defense solution are abundant and involve multiple layers of complexity. The Air Force Research Labs (AFRL) is currently investigating the feasibility of a holistic approach to network defense, called Cybercraft. We envision Cybercraft to be trusted computer entities that cooperate with other Cybercraft to provide autonomous and responsive network defense services. A top research goal …

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A Hybrid Communications Network Simulation-Independent Toolkit, David M. Dines Mar 2008

A Hybrid Communications Network Simulation-Independent Toolkit, David M. Dines

Theses and Dissertations

Net-centric warfare requires information superiority to enable decision superiority, culminating in insurmountable combat power against our enemies on the battlefield. Information superiority must be attained and retained for success in today’s joint/coalition battlespace. To accomplish this goal, our combat networks must reliably, expediently and completely deliver over a wide range of mobile and fixed assets. Furthermore, each asset must be given special consideration for the sensitivity, priority and volume of information required by the mission. Evolving a grand design of the enabling network will require a flexible evaluation platform to try and select the right combination of network strategies and …

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Multi-Objective Uav Mission Planning Using Evolutionary Computation, Adam J. Pohl Mar 2008

Multi-Objective Uav Mission Planning Using Evolutionary Computation, Adam J. Pohl

Theses and Dissertations

This investigation purports to develop a new model for multiple autonomous aircraft mission routing. Previous research both related and unrelated to this endeavor have used classic combinatoric problems as models for Unmanned Aerial Vehicle (UAV) routing and mission planning. This document presents the concept of the Swarm Routing Problem (SRP) as a new combinatorics problem for use in modeling UAV swarm routing, developed as a variant of the Vehicle Routing Problem with Time Windows (VRPTW). The SRP removes the single vehicle per target restraint and changes the customer satisfaction requirement to one of vehicle on location volume. The impact of …

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Feasibility Study Of Encoding Operational Mission Metadata Into Ipv6 Packet Headers, Timothy R. Policarpio Mar 2008

Feasibility Study Of Encoding Operational Mission Metadata Into Ipv6 Packet Headers, Timothy R. Policarpio

Theses and Dissertations

The purpose of this research is to determine the feasibility of using the header fields and header extensions of IPv6 packets to encode mission metadata into computer network streams. Specifically, this thesis seeks to answer several research questions addressing the performance of different packet header encoding methods, specifically which method provides the least end-to-end delay of a file transfer over a hypothetical network as well as which method produces the least amount of additional network overhead during its operation in the hypothetical network. The research questions are answered through a comprehensive literature review and with the use of several network …

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Establishing The Human Firewall: Reducing An Individual's Vulnerability To Social Engineering Attacks, Jamison W. Scheeres Mar 2008

Establishing The Human Firewall: Reducing An Individual's Vulnerability To Social Engineering Attacks, Jamison W. Scheeres

Theses and Dissertations

Hackers frequently use social engineering attacks to gain a foothold into a target network. This type of attack is a tremendous challenge to defend against, as the weakness lies in the human users, not in the technology. Thus far, methods for dealing with this threat have included establishing better security policies and educating users on the threat that exists. Existing techniques aren’t working as evidenced by the fact that auditing agencies consider it a given that will be able to gain access via social engineering. The purpose of this research is to propose a better method of reducing an individual’s …

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Behavior-Based Power Management In Autonomous Mobile Robots, Charles A. Fetzek Mar 2008

Behavior-Based Power Management In Autonomous Mobile Robots, Charles A. Fetzek

Theses and Dissertations

Current attempts to prolong the life of a robot on a single battery charge focus on lowering the operating frequency of the onboard hardware, or allowing devices to go to sleep during idle states. These techniques have much overhead and do not come built in to the underlying robotic architecture. In this thesis, battery life is greatly extended through development of a behavior-based power management system, including a Markov decision process power planner, thereby allowing future robots increased time to operate and loiter in their required domain. Behavior-based power management examines sensors needed by the currently active behavior set and …

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Dynamic Behavior Sequencing In A Hybrid Robot Architecture, Jeffrey P. Duffy Mar 2008

Dynamic Behavior Sequencing In A Hybrid Robot Architecture, Jeffrey P. Duffy

Theses and Dissertations

Hybrid robot control architectures separate plans, coordination, and actions into separate processing layers to provide deliberative and reactive functionality. This approach promotes more complex systems that perform well in goal-oriented and dynamic environments. In various architectures, the connections and contents of the functional layers are tightly coupled so system updates and changes require major changes throughout the system. This work proposes an abstract behavior representation, a dynamic behavior hierarchy generation algorithm, and an architecture design to reduce this major change incorporation process. The behavior representation provides an abstract interface for loose coupling of behavior planning and execution components. The hierarchy …

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Applying Automated Theorem Proving To Computer Security, Kelly K. Mcelroy Mar 2008

Applying Automated Theorem Proving To Computer Security, Kelly K. Mcelroy

Theses and Dissertations

While more and more data is stored and accessed electronically, better access control methods need to be implemented for computer security. Formal modelling and analysis have been successfully used in certain areas of computer systems, such as verifying the security properties of cryptographic and authentication protocols. However, formal models for computer systems in cyberspace, like networks, have hardly advanced. A highly regarded graduate textbook cites the Take-Grant model created in 1977 as one of the \current" examples of security modelling and analysis techniques. This model is rarely used in practice though. This research implements the Take-Grant Protection model's four de …

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Exploitation Of Self Organization In Uav Swarms For Optimization In Combat Environments, Dustin J. Nowak Mar 2008

Exploitation Of Self Organization In Uav Swarms For Optimization In Combat Environments, Dustin J. Nowak

Theses and Dissertations

This investigation focuses primarily on the development of effective target engagement for unmanned aerial vehicle (UAV) swarms using autonomous self-organized cooperative control. This development required the design of a new abstract UAV swarm control model which flows from an abstract Markov structure, a Partially Observable Markov Decision Process. Self-organization features, bio-inspired attack concepts, evolutionary computation (multi-objective genetic algorithms, differential evolution), and feedback from environmental awareness are instantiated within this model. The associated decomposition technique focuses on the iterative deconstruction of the problem domain state and dynamically building-up of self organizational rules as related to the problem domain environment. Resulting emergent …

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Conceptual Study Of Rotary-Wing Microrobotics, Kelson D. Chabak Mar 2008

Conceptual Study Of Rotary-Wing Microrobotics, Kelson D. Chabak

Theses and Dissertations

This thesis presents a novel rotary-wing micro-electro-mechanical systems (MEMS) robot design. Two MEMS wing designs were designed, fabricated and tested including one that possesses features conducive to insect level aerodynamics. Two methods for fabricating an angled wing were also attempted with photoresist and CrystalBond™ to create an angle of attack. One particular design consisted of the wing designs mounted on a gear which are driven by MEMS actuators. MEMS comb drive actuators were analyzed, simulated and tested as a feasible drive system. The comb drive resonators were also designed orthogonally which successfully rotated a gear without wings. With wings attached …

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A Secure Group Communication Architecture For A Swarm Of Autonomous Unmanned Aerial Vehicles, Adrian N. Phillips Mar 2008

A Secure Group Communication Architecture For A Swarm Of Autonomous Unmanned Aerial Vehicles, Adrian N. Phillips

Theses and Dissertations

This thesis investigates the application of a secure group communication architecture to a swarm of autonomous unmanned aerial vehicles (UAVs). A multicast secure group communication architecture for the low earth orbit (LEO) satellite environment is evaluated to determine if it can be effectively adapted to a swarm of UAVs and provide secure, scalable, and efficient communications. The performance of the proposed security architecture is evaluated with two other commonly used architectures using a discrete event computer simulation developed using MatLab. Performance is evaluated in terms of the scalability and efficiency of the group key distribution and management scheme when the …

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Field Guide To Genetic Programming, Nicholas Freitag Mcphee, Riccardo Poli, William B. Langdon Mar 2008

Field Guide To Genetic Programming, Nicholas Freitag Mcphee, Riccardo Poli, William B. Langdon

Computer Science Publications

No abstract provided.

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Traveling The Semantic Web Through Space, Time, And Theme, Amit P. Sheth, Matthew Perry Mar 2008

Traveling The Semantic Web Through Space, Time, And Theme, Amit P. Sheth, Matthew Perry

Kno.e.sis Publications

In this installment of Semantics and Services, we further develop the idea of spatial, temporal, and thematic (STT) processing of semantic Web data and describe the Web infrastructure needed to support it. Starting from Ramesh Jain's vision of the EventWeb as a view of what's possible with a Web that better accommodates all three dimensions of event-related information (thematic, spatial, and temporal), we outline the architecture needed to support it and current research that aims to realize it.

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Does Test-Driven Development Really Improve Software Design Quality?, David S. Janzen, Hossein Saiedian Mar 2008

Does Test-Driven Development Really Improve Software Design Quality?, David S. Janzen, Hossein Saiedian

Computer Science and Software Engineering

Software developers are known for adopting new technologies and practices on the basis of their novelty or anecdotal evidence of their promise. Who can blame them? With constant pressure to produce more with less, we often can’t wait for evidence before jumping in. We become convinced that competition won’t let us wait. Advocates for test-driven development claim that TDD produces code that’s simpler, more cohesive, and less coupled than code developed in a more traditional test-last way. Support for TDD is growing in many development contexts beyond its common association with Extreme Programming. Examples such as Robert C. Martin’s bowling …

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Test-Driven Learning In Early Programming Courses, David S. Janzen, Hossein Saiedian Mar 2008

Test-Driven Learning In Early Programming Courses, David S. Janzen, Hossein Saiedian

Computer Science and Software Engineering

Coercing new programmers to adopt disciplined development practices such as thorough unit testing is a challenging endeavor. Test-driven development (TDD) has been proposed as a solution to improve both software design and testing. Test-driven learning (TDL) has been proposed as a pedagogical approach for teaching TDD without imposing significant additional instruction time. This research evaluates the effects of students using a test-first (TDD) versus test-last approach in early programming courses, and considers the use of TDL on a limited basis in CS1 and CS2. Software testing, programmer productivity, programmer performance, and programmer opinions are compared between test-first and test-last programming …

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Prostate Segmentation On Pelvic Ct Images Using A Genetic Algorithm, Payel Ghosh, Melanie Mitchell Mar 2008

Prostate Segmentation On Pelvic Ct Images Using A Genetic Algorithm, Payel Ghosh, Melanie Mitchell

Computer Science Faculty Publications and Presentations

A genetic algorithm (GA) for automating the segmentation of the prostate on pelvic computed tomography (CT) images is presented here. The images consist of slices from three-dimensional CT scans. Segmentation is typically performed manually on these images for treatment planning by an expert physician, who uses the “learned” knowledge of organ shapes, textures and locations to draw a contour around the prostate. Using a GA brings the flexibility to incorporate new “learned” information into the segmentation process without modifying the fitness function that is used to train the GA. Currently the GA uses prior knowledge in the form of texture …

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Enhancing Jswat For Monitor-Based Executions, Arun Ramani Mar 2008

Enhancing Jswat For Monitor-Based Executions, Arun Ramani

Computer Science and Engineering Theses - Archive

Concurrent programs contain more than one thread that executes concurrently to accomplish a particular task. Since the threads in a concurrent program work together to accomplish a common goal, they share the data, code, resources and address space of their process. This reduces the overhead involved in creating and managing the threads but leads to side effects like race conditions, critical section problem and deadlocks. There are several operating system constructs to solve these issues such as locks, semaphores, monitors etc. Locks are associated with each object to control access of shared resources. Semaphores can be described as counters used …

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Visualization Of Monitor-Based Executions, Keerthika Koteeswaran Mar 2008

Visualization Of Monitor-Based Executions, Keerthika Koteeswaran

Computer Science and Engineering Theses - Archive

Concurrent programs play a vital role in the world of software engineering. Concurrent programs are used in various fields such as safety critical applications, applications involving advanced graphical user interface, operating system implementation etc. Concurrent programs due to their inherent multi-threaded nature pose a challenge to software engineers not only in coding but also in ensuring data consistency and accuracy. One of the important software constructs used by concurrent programmers to handle critical sections and data synchronization is monitors. A monitor is an encapsulation of shared data, operations on the data and any synchronization required to access the data~\cite{CarTai06:ModMulti}. Monitors …

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Output Feedback Controller For Operation Of Spark Ignition Engines At Lean Conditions Using Neural Networks, Jonathan B. Vance, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier Mar 2008

Output Feedback Controller For Operation Of Spark Ignition Engines At Lean Conditions Using Neural Networks, Jonathan B. Vance, Brian C. Kaul, Jagannathan Sarangapani, J. A. Drallmeier

Electrical and Computer Engineering Faculty Research & Creative Works

Spark ignition (SI) engines operating at very lean conditions demonstrate significant nonlinear behavior by exhibiting cycle-to-cycle bifurcation of heat release. Past literature suggests that operating an engine under such lean conditions can significantly reduce NO emissions by as much as 30% and improve fuel efficiency by as much as 5%-10%. At lean conditions, the heat release per engine cycle is not close to constant, as it is when these engines operate under stoichiometric conditions where the equivalence ratio is 1.0. A neural network controller employing output feedback has shown ability in simulation to reduce the nonlinear cyclic dispersion observed under …

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Digital Signal Processing Leveraged For Intrusion Detection, Theodore J. Erickson Mar 2008

Digital Signal Processing Leveraged For Intrusion Detection, Theodore J. Erickson

Theses and Dissertations

This thesis describes the development and evaluation of a novel system called the Network Attack Characterization Tool (NACT). The NACT employs digital signal processing to detect network intrusions, by exploiting the Lomb-Scargle periodogram method to obtain a spectrum for sampled network traffic. The Lomb-Scargle method for generating a periodogram allows for the processing of unevenly sampled network data. This method for determining a periodogram has not yet been used for intrusion detection. The spectrum is examined to determine if features exist above a significance level chosen by the user. These features are considered an attack, triggering an alarm. Two traffic …

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Dod Role For Securing United States Cyberspace, Jane J. Griffin Mar 2008

Dod Role For Securing United States Cyberspace, Jane J. Griffin

Theses and Dissertations

The cyber attacks on Estonia in late April and the early weeks of May 2007 significantly crippled the country, preventing it from performing banking, communications, news reporting, government transactions and command and control activities. Estonia is considered a “Wired Society”, much like the United States. Both countries rely on the cyberspace infrastructure economically and politically. Estonia sought assistance outside the country to recover from and to address the attacks. The cyber attacks on Estonia focused world-wide attention on the effects that cyberspace attacks could have on countries. If a cyber attack of national significance occurred against the United States, what …

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Obfuscation Framework Based On Functionally Equivalent Combinatorial Logic Families, Moses C. James Mar 2008

Obfuscation Framework Based On Functionally Equivalent Combinatorial Logic Families, Moses C. James

Theses and Dissertations

This thesis aims to be a few building blocks in the bridge between theoretical and practical software obfuscation that researchers will one day construct. We provide a method for random uniform selection of circuits based on a functional signature and specific construction specifiers. Additionally, this thesis includes the first formal definition of an algorithm that performs only static analysis on a program; that is analysis that does not rely on the input and output behavior of the analyzed program. This is analogous to some techniques used in real-world software reverse engineering. Finally, this thesis uses the equivalent circuit library to …

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An Investigation Into The Advantages, Mechanisms, And Developmental Challenges Of Scripted Mobile Routing, Boyeon Jang Mar 2008

An Investigation Into The Advantages, Mechanisms, And Developmental Challenges Of Scripted Mobile Routing, Boyeon Jang

Theses and Dissertations

Mobile Ad Hoc Network (MANET) routing protocols provide routing solutions in mobile wireless networks, without assuming any prior knowledge of topology nor any prediction of future topology. However, the resulting routes suffer from delay and consume precious bandwidth. Perfectly scripted routing could theoretically be optimal, (i.e., introduce no delay and cost no additional bandwidth), but would naturally be very fragile. This thesis explores a merging of these approaches, following a routing script if and when available, but reverting to a robust recovery approach otherwise. Script-Assisted Ad Hoc On-demand Distance Vector (S-AODV) routing protocol is designed to take advantage of prior …

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Symbolic Links In The Open Directory Project, Saverio Perugini Mar 2008

Symbolic Links In The Open Directory Project, Saverio Perugini

Computer Science Faculty Publications

We present a study to develop an improved understanding of symbolic links in web directories. A symbolic link is a hyperlink that makes a directed connection from a web page along one path through a directory to a page along another path. While symbolic links are ubiquitous in web directories such as Yahoo!, they are under-studied, and as a result, their uses are poorly understood. A cursory analysis of symbolic links reveals multiple uses: to provide navigational shortcuts deeper into a directory, backlinks to more general categories, and multiclassification. We investigated these uses in the Open Directory Project (ODP), the …

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At Issue, Bill Feireisen, George K. Thiruvathukal Mar 2008

At Issue, Bill Feireisen, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

In this installment of At Issue, two of CiSE's editorial board members describe the magazine's current and future Web presence. We start with Bill Feiereisen's discussion of science on the Web and what it could mean for CiSE ("Are We There Yet?") and end with George Thiruvathukal's discussion of the challenges therein ("If We Build It, Will They Come?"). CiSE's official homepage is www.computer.org/cise; we gladly welcome comments with suggestions or feedback. You can contact lead editor (Jenny Stout; [email protected]) or write to either Bill or George (their email addresses appear at the end of their respective essays).

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A Virtual Computing Laboratory, Joseph P. Kaylor, George K. Thiruvathukal Mar 2008

A Virtual Computing Laboratory, Joseph P. Kaylor, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

Many institutions choose to do periodic imaging of computers, which is both painstaking and limiting in terms of keeping software up to date. The authors describe an approach that builds on existing virtualization technologies.

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Grid Vertex-Unfolding Orthogonal Polyhedra, Mirela Damian Mar 2008

Grid Vertex-Unfolding Orthogonal Polyhedra, Mirela Damian

Computer Science: Faculty Publications

No abstract provided.

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