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Full-Text Articles in Engineering

Performance Analysis Of Dynamic Routing Protocols In A Low Earth Orbit Satellite Data Network, Richard F. Janoso Dec 1996

Performance Analysis Of Dynamic Routing Protocols In A Low Earth Orbit Satellite Data Network, Richard F. Janoso

Theses and Dissertations

Modern warfare is placing an increasing reliance on global communications. Currently under development are several Low Earth Orbit (LEO) satellite systems that propose to deliver voice and data traffic to subscribers anywhere on the globe. However, very little is known about the performance of conventional routing protocols under orbital conditions where the topology changes on a scale of minutes rather than days. This thesis compares two routing protocols in a LEO environment. One (Extended Bellman-Ford) is a conventional terrestrial routing protocol, while the other (Darting) is a new protocol which has been proposed as suitable for use in LEO networks. …


Local Area Network Implementation At The 4950th Test Wing: A Study Of The Relationship Between Individual Factors And The Effectiveness Of A Local Area Network, Doyle F. Cone, David J. Donahoo Dec 1993

Local Area Network Implementation At The 4950th Test Wing: A Study Of The Relationship Between Individual Factors And The Effectiveness Of A Local Area Network, Doyle F. Cone, David J. Donahoo

Theses and Dissertations

This research investigated the individual factors which directly impacted the effectiveness of the 4950th Test Wing local area network (LAN). Areas of interest included the relationships between demographic and user attitude factors and LAN effectiveness. A literature review provided the basis for: 1) operationally defining effectiveness as a subjective measure of user satisfaction; 2) identifying specific factors which impact information system effectiveness; and 3) developing a research instrument to measure user attitudes and user satisfaction. A questionnaire was administered to 342 LAN users 173 were returned (a response rate of 51 percent). Sixteen factors (eight demographic factors and eight attitude …


Satcom General Purpose Modem Dscs Iii Sct Beacon Telemetry Display, James D. Coppola Dec 1992

Satcom General Purpose Modem Dscs Iii Sct Beacon Telemetry Display, James D. Coppola

Theses and Dissertations

This thesis documents the design and implementation of a DSCS III single Channel Transponder (SCT) beacon telemetry display. The system is a personal computer based design which interfaces to three SCT beacon receiver/demodulators. The software was designed to decode and display both the DSCS III A and DSCS HI B satellite beacons. Recordings of the SCT beacon display can be made on paper and/or magnetic media when triggered by the user, a watchdog timer, or the SCT command accept telemetry bit. In addition, the system can be configured with an IRIG B Universal Time Coordinates (UTC) card which enables the …


Computer Simulation Of A General Purpose Satellite Modem, William L. Montgomery Jr. Dec 1992

Computer Simulation Of A General Purpose Satellite Modem, William L. Montgomery Jr.

Theses and Dissertations

The purpose of this research was to model and simulate the performance of a digital phase shift keyed satellite modem. The probability of bit error (P sub b) at different levels of energy per bit to noise power ratio (E sub b/N sub o) was the performance measure. The channel was assumed to contribute only additive white Gaussian noise. A second order Costas loop performs demodulation in the modem and was the key part of the simulation. The Costas loop with second order Butterworth arm filters was tested by finding the response to a phase or frequency step. The Costas …