UP	Paper 666	US-W-R	DOWN
A Methodology for Making Performance-Based Comparisons with Architectural Information
Doyle,Gerald		Defense Information Systems Agency
White,Elizabeth		George Mason University
Abstract —This paper demonstrates an approach to making early life cycle comparative performance assessments of alternative system architectures. Early problem identification reduces the likelihood of implementing designs that fail to meet performance goals. We restrict our technique to estimating performance differences early in the development phase, which is a critical step in identifying performance limitations. Designers routinely make assumptions both about the performance of the hardware platform and the software that will be used. Our approach simulates a queuing network model to provide a basis for making comparative performance assessments of architectures considered for system implementation, incorporating relevant known performance estimates. We will present results from the application of this technique to a case study that includes two ALOHA satellite network architectures. In this case, our early lifecycle assessment technique achieved a high degree of agreement with similar theoretical performance analysis models. The technique has the potential to allow a designer to investigate more easily "what-if" questions, enabling them to better understand the performance implications of alternative architectural proposals.
Mr. Gerald S. Doyle was born January 25, 1951, in Morristown, NJ. He was awarded a Bachelor of Science degree from the United States Military Academy in 1973, a Masters Degree in Electrical Engineering from the Naval Postgraduate School in 1980, and a Masters Degree in Computer Science from George Mason University in 2000. He is currently a doctoral candidate at George Mason University in Computer Science where he conducts research in methods for making comparative architecture-based performance evaluations of software intensive systems. Prior to entering the civil service, Mr. Doyle served in the United States Army for twenty years after receiving his commission in 1973. He returned to the Defense Information Systems Agency in 1991. During his service in a variety of satellite and space related assignments, he helped engineer technical standards for communication and network control for the SATCOM environment. As part of a recent DISA transformational effort he was selected to be the Chief Engineer and Deputy of the Transport Division. In October of 2004, he was chosen to be the Chief of the DISA Systems Engineering Architecture and Integration Center. He currently heads the DISA Systems Engineering Center.