The most important one is the systems engineering

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Unformatted text preview: al portion. Combining the selection rule with the results of the analytical activity should enable the system engineer to array the alternatives from most preferred to least, in essence making a tentative selection. This tentative selection should not be accepted blindly. In most trade studies, there is a need to subject the results to a "reality check" by considering a number of questions. Have the goals, objectives, and constraints truly been met? Is the tentative selection heavily dependent on a particular set of input values to the measurement methods, or does it hold up under a range of reasonable input values? (In the latter case, the tentative selection is NASA Systems Engineering Handbook Systems Analysis and Modeling Issues said to be robust.) Are there sufficient data to back up the tentative selection? Are the measurement methods sufficiently discriminating to be sure that the tentative selection is really better than other alternatives? Have the subjective aspects of the problem been fully addressed? If the answers support the tentative selection, then the system engineer can have greater confidence in a recommendation to proceed to a further resolution of the system design, or to the implementation of that design. The estimates of system effectiveness, its underlying performance or technical attributes, and system cost generated during the trade study process serve as inputs to that further resolution. The analytical portion of the trade study process often provide the means to quantify the performance or technical (and cost) attributes that the system's lower levels must meet. These can be formalized as performance requirements. If the reality check is not met, the trade study process returns to one or more earlier steps. This iteration may result in a change in the goals, objectives, and constraints, a new alternative, or a change in the selection rule, based on the new information generated during the trade study. The reality check may, at times, lead instead to a decision to first impr...
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This document was uploaded on 02/26/2014 for the course E 515 at University of Louisiana at Lafayette.

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