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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Analysis and comparison of DoDAF and ZACHMAN framework for use as the architecture for the United States Coast Guard's maritime patrol (WPC)

Griffin, Latan K. 09 1900 (has links)
WMSM ) and Maritime Patrol Coastal (WPC). The System Architecture Description Document (SADD), which describes architectural framework that is used to establish the rules, guidance, and product descriptions for developing and presenting architecture descriptions that ensure a common denominator for understanding, comparing, and integrating architectures needs to be written for the WPC. The SADD has been written, established and contractual agreed upon for both the Large and Medium Cutters. However, their missions dictate that they have littoral capabilities and the capacity to conduct missions with naval vessels; therefore the C4ISR architecture was chosen for their SADD as it fits their mission statements. The mission of the WPC is of a different nature. It is not expected to carry out the same functions as the larger cutters and its capabilities will be more of a littoral function. Therefore the application of its architectural Framework will enable architectures to contribute most effectively to building an interoperable and cost effective system subject to the needs of the WPC mission. This thesis proposes to compare two different architectural frameworks for use by the WPCâ s SADD: 1) DoD Architecture Framework and 2) Zachman Architecture Framework. The thesis will compare and recommend the architectural framework that will at most enhance the mission statement set forth by the Original Requirements Document (ORD) of the WPC.
42

Frequency and polarization diversity jamming of communications in urban environments

Ulama, Tuncay 09 1900 (has links)
The purpose of this research is to investigate how to exploit frequency and polarization techniques in reducing the effects of jamming against UAV relay communication links in an urban warfare environment. There have been early studies investigating the diversity techniques against multipath and fading problems in urban environments. A medium without any jamming issues seems almost impossible to exist in today's warfare. Basically, noise jamming issues were taken into consideration. Urbana Wireless Toolset was used as the computer simulation. Even though it is a powerful tool to predict the radio wave propagation in urban environments, due to the problems about modeling the cities (lack of detail, like the shapes of the buildings, objects and vehicles that could be found in the streets, and other details that would contribute to the propagation mechanisms), it can only give us a trend with some guidelines instead of an exact mapping of propagation.
43

Full spectrum information operations and the information professional officer intermediate qualification process filling the gap to ensure the continued leadership of the information professional community in the area of information dominance

Velasco, Diego. 09 1900 (has links)
There currently exists a major effort within the United States Navy's Information Professional (IP) Community to overhaul and improve the qualification process for its officers. The overall effort has included the addition of technical refresher courses, re-examination of the Continuing Education Units (CEU) system, and the improvement of the Basic, Intermediate, and Advanced Qualification programs. This thesis specifically addresses the Intermediate Qualification (IQ) and the lack of Information Operations (IO) concepts therein. While some portions of the IQ that address highly technical areas exist, there is little to no mention of the importance of and concepts contained within IO, as defined by Joint Doctrine. The IP Community has a unique opportunity to train its officers in the concepts, competencies, and supporting activities of IO. This will ensure that the IP Community continues to be the Navy's leaders in the area of information dominance. This thesis provides recommended line items for injection into the IP IQ in the appropriate format with discussions and definitions that address the specific line items. The thesis also provides further recommendations for the continuing improvement and refinement of the IP qualification process, especially in the area of IO.
44

Data set simulation and RF path modeling of a QPSK radio communication system

Sun, Wei-Long. 09 1900 (has links)
This project simulates QPSK modulation signals and uses a laboratory environment to create deteriorating effects of real-world high frequency (HF) transmissions that may modify the ideal QPSK waveform. These modifications may be identifiable in order to "fingerprint" the source of the modifications. To simulate the transmission path in the real world a signal generator is used to create the QPSK I/Q signal at the HF operating frequencies and a digital sampling oscilloscope acts as a receiver and records the data for analysis. A computer with MATLAB Instrument-control Toolbox is used to generate a random-input data stream as an input to the signal generator, which modulates the RF signal. The RF signal was chosen to be at HF (5-15 MHz) and the QPSK modulation was at 9600 baud. The deterioration effects of a real-world transmitter site were chosen to be associated with the output amplifier linearity and with the transmission line condition between the transmitter and antenna.
45

Scattering from multi-layered metamaterials using wave matrices

Cotuk, Umit. 09 1900 (has links)
The complex permittivity ( )Ì and permeability ( æ) of a material determine the response of the material to electromagnetic radiation. Usually, the real parts of Ì and æ are positive for naturally occurring materials at microwave frequencies. Metamaterials are engineered media that are designed to have either a negative permittivity or permeability or both. Negative permeability and negative permittivity would cause electromagnetic waves traveling through this medium to exhibit unusual characteristics such as power flow in a direction opposite to the phase velocity. In this thesis, the wave matrix approach is used to calculate the total reflection and transmission coefficients of a multilayered structure. The method is applicable to all types of materials, including metamaterials. Several layered configurations are studied including both metamaterial and conventional dielectric layers. A MATLAB program is developed to examine the effects of frequency, angle of incidence and polarization. The results are compared to published data. Potential applications of metamaterials are also discussed.
46

Performance analysis of IEEE 802.11g signals under different operational environments

Filtikakis, Stefanos 09 1900 (has links)
A modern military environment requires flexible, capable and robust communications systems. Wireless communications infrastructures can provide all these services that are absolutely necessary to the soldiers on the battlefield or to the mission planners. The IEEE 802.11g wireless LAN seems to fit the military needs since it can provide data rates up to 54 Mbps and it is backward compatible with the earlier 802.11b specification. The purpose of this thesis was to implement, analyze and evaluate the performance of an outdoor point-to-point 802.11g WLAN under different operational environments. The implementation was achieved using two low-cost commercially available wireless bridges and directional external antennas from a well-known manufacturer, Cisco. As part of the analysis, the effective throughput of this standard, the packet error rate and the received signal strength were measured in each of the following three environments: suburban area, medium density vegetation, and coastal. The signal path loss was then calculated from the recorded results and was compared to theoretical results from common outdoor propagation models. A new path loss exponent, n, was also estimated for each case. Based on this exponent, the free space path loss model was properly modified in order to fit the measured path loss results.
47

Systems analysis of alternative architectures for Riverine Warfare in 2010

Oliveria, Tristan V., Beaver, James W., Mercado, Pedro R., Bucher, Andrew D., Free, Jennifer M., Byers, Richard W. 12 1900 (has links)
Student Integrated Project / Includes supplementary material. / This thesis analyzed the Navy's proposed Riverine Force (RF) structure and capabilities of 2006. Systems Engineering and Analysis cohort 10 (SEA10) developed a cost-effective system of systems which increased battlespace awareness and situational responsiveness for 2010. Riverine missions were decomposed into their functional, physical, and operational architectures using the detect-to-engage sequence. This analysis determined critical RF functions. Critical functions detect and engage were then physically represented by feasible force package alternatives that augmented the baseline RF. SEA10 analyzed these alternatives using agent based models to identify baseline RF capability gaps and provide insights into possible solutions. Reduction of modeling data indicated the baseline force was as effective as some upgraded force packages depending on the measure of performance (MOP) or scenario structure under scrutiny. Sensor augmentation demonstrated significant improvements to baseline performance by increasing battlespace awareness. Weapon augmentation alone did not significantly improve baseline performance by increasing situational responsiveness. Combined sensor-weapon augmentation performed well across all MOP and scenarios. The Unmanned Surface Vehicle (USV) was the most cost-effective alternative. Dedicated helicopter support demonstrated the best performance overall, but was the most costly alternative.
48

Analysis and comparison of various requirements management tools for use in the shipbuilding industry

Clark, Eric D. 09 1900 (has links)
Requirements are the cornerstone of all contracts for products and services. If requirements are not well defined and managed, the product or service may fail to meet the customer's needs and costs may go up. This is especially true in the shipbuilding industry where the customer has many requirements. Some are clearly defined while many more are undefined. Some requirements have to be generated from the implication of other requirements while even more have to be pulled from other industry or military standards. This amounts to hundreds or thousands of requirements. Without the proper tools, managing all these requirements would be next to impossible. This thesis investigates requirements management "Best Practices" and relate them to the needs of Systems Engineering in shipbuilding. This thesis also compares and analyzes several requirements management tools to see what may be the best fit for the shipbuilding industry in vessel design. This thesis provides recommendation of a specific requirements management tool and its suggested use.
49

Extracting material constitutive parameters from scattering parameters

Feng, Bo-Kai 09 1900 (has links)
In the frequency domain all materials can be described electrically by their complex permittivity and permeability. These constitutive parameters determine the response of the material to electromagnetic (EM) radiation. The precise knowledge of complex permittivity and permeability is required not only for scientific but also for industrial applications. Due to the uncertainties in manufacturing processes, often the only way to find a material's parameters is to measure them. The concept of metamaterials, exhibiting negative permittivity and permeability, is attracting a lot of attention. Such materials are also termed left-handed materials (LHMs). This thesis examines several methods to determine the effective permittivity and permeability of both normal materials and metamaterials. CST Microwave Studio is used to model the materials in both free space and rectangular waveguide environments to calculate the S-parameters (S11 and S21) from which the constitutive parameters can be extracted.
50

Propagation modeling of wireless systems on shipboard external decks

Rodriguez Gallo, Luis E. 09 1900 (has links)
Many onboard ship operations demand full radio coverage over the entire ship, not only indoor, but also from the interior spaces to the other decks. Onboard a ship, specifically in the upper decks, radio wave propagation is subjected to fading that would impede the quality and reliability of data links and communication. One example is the performance of unmanned aerial vehicle (UAV) data and communications links. The purpose of this thesis is to analyze, model, and simulate some communication scenarios that occur on naval ships using Urbana. Starting from known inputs (frequency, ship compartment geometry, material properties, propagation computation model, and antenna type), analytical results reflecting the propagation mechanisms and coverage area are presented. Variable inputs can then be optimized to achieve a desired signal distribution for a specific shipboard environment. The ship models were created by Rhino, a well-known Windows-based computer drawing software. The values of the signals received on the different points in the main deck are computed for different frequencies and powers. The results are used to draw conclusions of the deployment of antennas on the ship as well as operational aspects such as UAV flight paths.

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