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Theses/Dissertations

Computer Engineering

2008

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Articles 31 - 60 of 73

Full-Text Articles in Engineering

Constellation Design Of Geosynchronous Navigation Satellites Which Maximizes Availability And Accuracy Over A Specified Region Of The Earth, Halil Ibrahim Ozdemir Mar 2008

Constellation Design Of Geosynchronous Navigation Satellites Which Maximizes Availability And Accuracy Over A Specified Region Of The Earth, Halil Ibrahim Ozdemir

Theses and Dissertations

Currently, there are four Global Navigation Satellite Systems (GNSS) either being developed or in existence-GPS, GLONASS, Compass, and Galileo. Additionally, there are several Regional Navigation Satellite Systems (RNSS) planned or in existence, as well as numerous augmentation systems (which require a GNSS for operation). It can be anticipated that there will be interest in developing additional independent regional navigation satellite systems to cover areas of interest to particular countries or regions, who want to have their own system. In this paper, a genetic algorithm is used in an effort to determine near-optimal RNSS constellations. First, a cost function is setup, …

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Dialable Cryptography For Wireless Networks, Marnita T. Eaddie Mar 2008

Dialable Cryptography For Wireless Networks, Marnita T. Eaddie

Theses and Dissertations

The objective of this research is to develop an adaptive cryptographic protocol, which allows users to select an optimal cryptographic strength and algorithm based upon the hardware and bandwidth available and allows users to reason about the level of security versus the system throughput. In this constantly technically-improving society, the ability to communicate via wireless technology provides an avenue for delivering information at anytime nearly anywhere. Sensitive or classified information can be transferred wirelessly across unsecured channels by using cryptographic algorithms. The research presented will focus on dynamically selecting optimal cryptographic algorithms and cryptographic strengths based upon the hardware and …

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Mission Impact Analysis Visualization For Enhanced Situational Awareness, Sean C. M. Carroll Mar 2008

Mission Impact Analysis Visualization For Enhanced Situational Awareness, Sean C. M. Carroll

Theses and Dissertations

This research effort examines the creation of mission impact analysis visualizations to enhance situational awareness. It focuses on using prefuse to create a visualization that allows the user to quickly understand the impact of the failure of any element needed directly or indirectly for a mission. The visualization correctly identifies the direct or indirect impact on physical requirements such as network links and servers as well as non-physical elements such as the generation of a report, or ability to perform a task. The visualization provides an overview of the situation, as well as including enhancements to allow for greater detail …

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Evaluating Security And Quality Of Service Considerations In Critical Infrastructure Communication Networks, Gregory R. Roberts Mar 2008

Evaluating Security And Quality Of Service Considerations In Critical Infrastructure Communication Networks, Gregory R. Roberts

Theses and Dissertations

This thesis demonstrates the benefits of utility communication based on Internet technology, some dangers in using Internet technology in establishing a utility intranet connecting protection and control systems, and compares three different approaches to making reservations for routing traffic in the utility intranet based on different levels of background traffic. A model of expected background traffic on a national utility intranet is presented. The Utility Communication Architecture 2.0 and the International Electrotechnical Commission (IEC) 61850 began laying the groundwork in 2002 in establishing an infrastructure allowing power substations, program logic controllers, remote terminal units, intelligent electronic devices, and other devices …

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Network Visualization Design Using Prefuse Visualization Framework, John Mark Belue Mar 2008

Network Visualization Design Using Prefuse Visualization Framework, John Mark Belue

Theses and Dissertations

Visualization of network simulation events or network visualization is an effective and low cost method to evaluate the health and status of a network and analyze network designs, protocols, and network algorithms. This research designed and developed a network event visualization framework using an open source general visualization toolkit. This research achieved three major milestones during the development of this framework: A robust network simulator trace file parser, multiple network visualization layouts {including user-defined layouts, and precise visualization timing controls and integrated display of network statistics. The parser architecture is extensible to allow customization of simulator trace formats that are …

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Hardware Algorithm Implementation For Mission Specific Processing, Jason W. Shirley Mar 2008

Hardware Algorithm Implementation For Mission Specific Processing, Jason W. Shirley

Theses and Dissertations

There is a need to expedite the process of designing military hardware to stay ahead of the adversary. The core of this project was to build reusable, synthesizeable libraries to make this a possibility. In order to build these libraries, Matlab® commands and functions, such as Conv2, Round, Floor, Pinv, etc., had to be converted into reusable VHDL modules. These modules make up reusable libraries for the Mission Specific Process (MSP) which will support AFRL/RY. The MSP allows the VLSI design process to be completed in a mere matter of days or months using an FPGA or ASIC design, as …

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Priority Based Buffering Over Multiple Lossy Links Using Tcp Aware Layer Buffering, Kevin J. Savidge Mar 2008

Priority Based Buffering Over Multiple Lossy Links Using Tcp Aware Layer Buffering, Kevin J. Savidge

Theses and Dissertations

Wireless military information systems require high reliability, which is difficult to achieve in adverse conditions. To provide high reliability, one must overcome packet loss across multiple wireless hops. Buffering packets in a lossy environment is well explored; however, the ability to selectively buffer TCP traffic across multiple lossy links is a new area of research. This document seeks to explore the delivery of high priority traffic in a lossy environment and conclude that prioritized buffing can increase the probability that a high priority download will finish, where others will fail. It is shown that buffering provides six times the throughput …

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Hot Swapping Protocol Implementations In The Opnet Modeler Development Environment, Mark E. Coyne Mar 2008

Hot Swapping Protocol Implementations In The Opnet Modeler Development Environment, Mark E. Coyne

Theses and Dissertations

This research effort demonstrates hot swapping protocol implementations in OPNET via the building of a dependency injection testing framework. The thesis demonstrates the externalization (compiling as stand-alone code) of OPNET process models, and their inclusion into custom DLL's (Dynamically Linked Libraries). A framework then utilizes these process model DLL's, to specify, or “inject,” process implementations post-compile time into an OPNET simulation. Two separate applications demonstrate this mechanism. The first application is a toolkit that allows for the testing of multiple routing related protocols in various combinations without code re-compilation or scenario re-generation. The toolkit produced similar results as the same …

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Scripted Mobile Network Routing In A Contested Environment, Anthony R. Otto Mar 2008

Scripted Mobile Network Routing In A Contested Environment, Anthony R. Otto

Theses and Dissertations

Mobile wireless network protocols currently run on optimistic routing algorithms, adjusting node connectivity only when the chosen connectivity metrics, such as signal strength, pass beyond minimum thresholds. Optimistic routing has several weaknesses. Optimistic routing suffers from increased network overhead during increased frequency of node movement and increased node density per area, and optimistic routing also suffers from non-optimistic access change for individual nodes. The overall communication throughput of a network may be increased if the network topology change is scripted; a scripted plan can allow messages to travel along a more efficient topological path while creating less topology control traffic. …

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Semantic Components: A Model For Enhancing Retrieval Of Domain- Specific Information, Susan Loucette Price Mar 2008

Semantic Components: A Model For Enhancing Retrieval Of Domain- Specific Information, Susan Loucette Price

Dissertations and Theses

Despite the success of general Internet search engines, information retrieval remains an incompletely solved problem. Our research focuses on supporting domain experts when they search domain-specific libraries to satisfy targeted information needs. The semantic components model introduces a schema specific to a particular document collection. A semantic component schema consists of a two-level hierarchy, document classes and semantic components. A document class represents a document grouping, such as topic type or document purpose. A semantic component is a characteristic type of information that occurs in a particular document class and represents an important aspect of the document’s main topic. …

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Mobile User Movement And Service Usage Prediction Using Bayesian Learning For Neural Networks, Sherif Hany Akoush Feb 2008

Mobile User Movement And Service Usage Prediction Using Bayesian Learning For Neural Networks, Sherif Hany Akoush

Archived Theses and Dissertations

No abstract provided.

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Aspectization Of Web Applications Quality Of Service Measures, Lamya Atef Othman Tantawy Feb 2008

Aspectization Of Web Applications Quality Of Service Measures, Lamya Atef Othman Tantawy

Archived Theses and Dissertations

No abstract provided.

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Kerberos Phone Secure Messenger, Nabeel Al-Saber Jan 2008

Kerberos Phone Secure Messenger, Nabeel Al-Saber

Theses

Security is becoming vital in today's open insecure Internet. While popular Internet enabled mobile devices are spreading widely, the security of such platforms is not maturely addressed. This research extends the popular Kerberos authentication protocol to run on mobile phones and builds a novel Kerberos Secure Phone Messenger (KSPM) on top of the protocol. Moreover, the Kerberos network authentication protocol provides user authentication and message privacy with the convenience of secret key cryptography. Such an advantage in mobile phones helps reduce the computational burden and power consumption if compared with public key cryptography. KSPM achieves high standards in terms of …

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Retransmission Strategies For Moving Networks Over Ricean Fading Channels, Alex Ruiz Lee Jan 2008

Retransmission Strategies For Moving Networks Over Ricean Fading Channels, Alex Ruiz Lee

Theses

The problem of designing retransmission protocols based on Hybrid Automatic Repeat reQuest (HARQ) for moving networks over Ricean fading channels has been considered. The scenario of interest consists of one receiver traveling at a given speed while connected to a wireless network based on OFDM (e.g., WiMax) through several base stations located along the path. Five different retransmission protocols that combine HARQ with handover between adjacent base stations are considered. Their performance in terms of number of retransmissions per packet via numerical simulations, considering both frequency selective and nonselective channels are presented. The results obtained show the relevant advantage that …

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Proactive Methods For Measurement Of Available Bandwidth And Link Capacity, Khondaker Musfakus Salehin Jan 2008

Proactive Methods For Measurement Of Available Bandwidth And Link Capacity, Khondaker Musfakus Salehin

Theses

With the continuous expansion of network infrastructure and deployment of applications sensitive to Quality-of-Service, network measurement plays a major role in both network planning and management. Accurate measurement of various network parameters, e.g., available bandwidth, link capacity, delay, packet loss and jitter, provides a positive impact for effective traffic engineering, Quality-of-Service (QoS) routing, optimization of end-to-end transport performance, and link capacity planning. For network measurement, there exists several proactive estimation tools based on either probe-gap model or probe-rate model that estimate path related attributes. Most of these tools that have been implemented can measure tight-link capacity (smallest available bandwidth) and/or …

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Two Factor Authentication And Authorization In Ubiquitous Mobile Computing, Qing Zhu Jan 2008

Two Factor Authentication And Authorization In Ubiquitous Mobile Computing, Qing Zhu

Theses

Handheld devices, such as mobile phones, PDAs and others, have become an integrated part of our lives. They are perfectly suitable to become the first real-life platforms for mobile computing applications. A lightweight holistic authentication and authorization scheme is presented for this typical wireless scenario. It is shown that either SIM or Kerberos authentication has its limitations. A two-factor authentication method SIM-based Kerberos authentication is developed to implement the Secure Single Sign-on function with LDAP protocol realization for authorization and mobile directory services. Performance analysis and power consumption analyses for this protocol are presented as well. Our results show that …

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Implementación De Una Interfaz Hmi Para La Operación Del Módulo Control De Procesos Del Laboratorio De Robótica, Jhon Jairo Grueso Delgado Jan 2008

Implementación De Una Interfaz Hmi Para La Operación Del Módulo Control De Procesos Del Laboratorio De Robótica, Jhon Jairo Grueso Delgado

Ingeniería en Automatización

Para poder implementar una interfaz humano-máquina en el modulo control de procesos, se deben conocer los distintos tipos de software diseñados para el diseño de esta aplicación así como el estándar utilizado para la comunicación entre PLC y computador. Antes de entrar a implementar la interfaz se realizó una descripción del modulo para conocer sus componentes y realizar pruebas a los mismos. Se hizo una revisión a los planos existentes, realizando algunos cambios en las conexiones eléctricas para poner en funcionamiento el equipo, después de estar funcionando se procedió a realizar la configuración del PLC que es uno de los …

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Threat-Driven Security Architecture Modeling And Analysis Of Web Services-Based Systems, Yomna Mostafa El-Sayed Aly Jan 2008

Threat-Driven Security Architecture Modeling And Analysis Of Web Services-Based Systems, Yomna Mostafa El-Sayed Aly

Archived Theses and Dissertations

No abstract provided.

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Dynamic Task Allocation In Mobile Robot Systems Using Utility Funtions, Scott Vander Weide Jan 2008

Dynamic Task Allocation In Mobile Robot Systems Using Utility Funtions, Scott Vander Weide

Electronic Theses and Dissertations

We define a novel algorithm based on utility functions for dynamically allocating tasks to mobile robots in a multi-robot system. The algorithm attempts to maximize the performance of the mobile robot while minimizing inter-robot communications. The algorithm takes into consideration the proximity of the mobile robot to the task, the priority of the task, the capability required by the task, the capabilities of the mobile robot, and the rarity of the capability within the population of mobile robots. We evaluate the proposed algorithm in a simulation study and compare it to alternative approaches, including the contract net protocol, an approach …

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Optimizing Dynamic Logic Realizations For Partial Reconfiguration Of Field Programmable Gate Arrays, Matthew Parris Jan 2008

Optimizing Dynamic Logic Realizations For Partial Reconfiguration Of Field Programmable Gate Arrays, Matthew Parris

Electronic Theses and Dissertations

Many digital logic applications can take advantage of the reconfiguration capability of Field Programmable Gate Arrays (FPGAs) to dynamically patch design flaws, recover from faults, or time-multiplex between functions. Partial reconfiguration is the process by which a user modifies one or more modules residing on the FPGA device independently of the others. Partial Reconfiguration reduces the granularity of reconfiguration to be a set of columns or rectangular region of the device. Decreasing the granularity of reconfiguration results in reduced configuration filesizes and, thus, reduced configuration times. When compared to one bitstream of a non-partial reconfiguration implementation, smaller modules resulting in …

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Sustainable Fault-Handling Of Reconfigurable Logic Using Throughput-Driven Assessment, Carthik Sharma Jan 2008

Sustainable Fault-Handling Of Reconfigurable Logic Using Throughput-Driven Assessment, Carthik Sharma

Electronic Theses and Dissertations

A sustainable Evolvable Hardware (EH) system is developed for SRAM-based reconfigurable Field Programmable Gate Arrays (FPGAs) using outlier detection and group testing-based assessment principles. The fault diagnosis methods presented herein leverage throughput-driven, relative fitness assessment to maintain resource viability autonomously. Group testing-based techniques are developed for adaptive input-driven fault isolation in FPGAs, without the need for exhaustive testing or coding-based evaluation. The techniques maintain the device operational, and when possible generate validated outputs throughout the repair process. Adaptive fault isolation methods based on discrepancy-enabled pair-wise comparisons are developed. By observing the discrepancy characteristics of multiple Concurrent Error Detection (CED) configurations, …

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A Competitive Reconfiguration Approach To Autonomous Fault Handling Using Genetic Algorithms, Kening Zhang Jan 2008

A Competitive Reconfiguration Approach To Autonomous Fault Handling Using Genetic Algorithms, Kening Zhang

Electronic Theses and Dissertations

In this dissertation, a novel self-repair approach based on Consensus Based Evaluation (CBE) for autonomous repair of SRAM-based Field Programmable Gate Arrays (FPGAs) is developed, evaluated, and refined. An initial population of functionally identical (same input-output behavior), yet physically distinct (alternative design or place-and-route realization) FPGA configurations is produced at design time. During run-time, the CBE approach ranks these alternative configurations after evaluating their discrepancy relative to the consensus formed by the population. Through runtime competition, faults in the logical resources become occluded from the visibility of subsequent FPGA operations. Meanwhile, offspring formed through crossover and mutation of faulty and …

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A Reinforcement Learning Technique For Enhancing Human Behavior Models In A Context-Based Architecture, David Aihe Jan 2008

A Reinforcement Learning Technique For Enhancing Human Behavior Models In A Context-Based Architecture, David Aihe

Electronic Theses and Dissertations

A reinforcement-learning technique for enhancing human behavior models in a context-based learning architecture is presented. Prior to the introduction of this technique, human models built and developed in a Context-Based reasoning framework lacked learning capabilities. As such, their performance and quality of behavior was always limited by what the subject matter expert whose knowledge is modeled was able to articulate or demonstrate. Results from experiments performed show that subject matter experts are prone to making errors and at times they lack information on situations that are inherently necessary for the human models to behave appropriately and optimally in those situations. …

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An Adaptive Multiobjective Evolutionary Approach To Optimize Artmap Neural Networks, Assem Kaylani Jan 2008

An Adaptive Multiobjective Evolutionary Approach To Optimize Artmap Neural Networks, Assem Kaylani

Electronic Theses and Dissertations

This dissertation deals with the evolutionary optimization of ART neural network architectures. ART (adaptive resonance theory) was introduced by a Grossberg in 1976. In the last 20 years (1987-2007) a number of ART neural network architectures were introduced into the literature (Fuzzy ARTMAP (1992), Gaussian ARTMAP (1996 and 1997) and Ellipsoidal ARTMAP (2001)). In this dissertation, we focus on the evolutionary optimization of ART neural network architectures with the intent of optimizing the size and the generalization performance of the ART neural network. A number of researchers have focused on the evolutionary optimization of neural networks, but no research has …

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Efficient And Scalable Network Security Protocols Based On Lfsr Sequences, Saikat Chakrabarti Jan 2008

Efficient And Scalable Network Security Protocols Based On Lfsr Sequences, Saikat Chakrabarti

University of Kentucky Doctoral Dissertations

The gap between abstract, mathematics-oriented research in cryptography and the engineering approach of designing practical, network security protocols is widening. Network researchers experiment with well-known cryptographic protocols suitable for different network models. On the other hand, researchers inclined toward theory often design cryptographic schemes without considering the practical network constraints. The goal of this dissertation is to address problems in these two challenging areas: building bridges between practical network security protocols and theoretical cryptography. This dissertation presents techniques for building performance sensitive security protocols, using primitives from linear feedback register sequences (LFSR) sequences, for a variety of challenging networking applications. …

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Matrix Decomposition For Data Disclosure Control And Data Mining Applications, Jie Wang Jan 2008

Matrix Decomposition For Data Disclosure Control And Data Mining Applications, Jie Wang

University of Kentucky Doctoral Dissertations

Access to huge amounts of various data with private information brings out a dual demand for preservation of data privacy and correctness of knowledge discovery, which are two apparently contradictory tasks. Low-rank approximations generated by matrix decompositions are a fundamental element in this dissertation for the privacy preserving data mining (PPDM) applications. Two categories of PPDM are studied: data value hiding (DVH) and data pattern hiding (DPH). A matrix-decomposition-based framework is designed to incorporate matrix decomposition techniques into data preprocessing to distort original data sets. With respect to the challenge in the DVH, how to protect sensitive/confidential attribute values without …

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Asynchronous Nanowire Crossbar Architecture For Manufacturability, Modularity And Robustness, Ravi Bonam Jan 2008

Asynchronous Nanowire Crossbar Architecture For Manufacturability, Modularity And Robustness, Ravi Bonam

Masters Theses

"This thesis spotlights the dawn of a promising new nanowire crossbar architecture, the Asynchronous crossbar architecture, in the form of three different articles. It combines the reduced size of the nanowire crossbar architecture with the clock-free nature of Null Conventional Logic, which are the primary advantages. The first paper explains the proposed architecture with illustrations, including the design of an optimized full adder. This architecture has an elementary structure termed as a Programmable Gate Macro Block (PGMB) which is analogous to a threshold gate in NCL. The other two papers concentrate on mapping and placement techniques which are important due …

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Development And Validation Of A Microcontroller Emissions Model, Shaohua Li Jan 2008

Development And Validation Of A Microcontroller Emissions Model, Shaohua Li

Masters Theses

"A model of the power delivery network of a microcontroller was developed to predict the radiated and conducted emissions from the integrated circuit (IC). A SPICE model of the power delivery network, similar to the ICEM model, was developed for a microcontroller running a typical program and used to predict the noise voltage between the power and return planes of a printed circuit board (PCB).

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An Approach For Human Swarm Interaction, Shishir Bashyal Jan 2008

An Approach For Human Swarm Interaction, Shishir Bashyal

Masters Theses

"This study shows that appropriate human interaction can benefit a swarm of robots to reach to goal more efficiently. The common belief in swarm robotics that user intervention adversely affects intelligence of the swarm is studied carefully to show that the traditional human-robot interaction approaches are not suitable for human swarm interaction. A set of desirable features for human swarm interaction is identified and an interaction architecture is proposed that has all of the desirable features. A swarm simulation environment is then created that allows simulating a swarm behavior in an indoor environment. Three different applications of the swarm are …

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Probabilistic Analysis Of Defect Tolerance In Asynchronous Nano Crossbar Architecture, Shikha Chaudhary Jan 2008

Probabilistic Analysis Of Defect Tolerance In Asynchronous Nano Crossbar Architecture, Shikha Chaudhary

Masters Theses

"Among recent advancements in technology, nanotechnology is particularly promising. Most researchers have begun to focus their efforts on developing nano scale circuits. Nano scale devices such as carbon nano tubes (CNT) and silicon nano wires (SiNW) form the primitive building blocks of many nano scale logic devices and recently developed computing architecture. One of the most promising nanotechnologies is crossbar-based architecture, a two-dimensional nanoarray, formed by the intersection of two orthogonal sets of parallel and uniformly-spaced CNTs or SiNWs. Nanowire crossbars offer the potential for ultra-high density, which has never been achieved by photolithography. In an effort to improve these …

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