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resolution), and constraints
The measures and measurement methods
All data sources used
The alternatives chosen for analysis
uncertainty ranges and sensitivity analyses
The selection rule used
The recommended alternative. Trade study reports should be maintained
as part of the system archives so as to ensure
traceability of decisions made through the systems
engineering process. Using a generally consistent
format for these reports also makes it easier to review
and assimilate them into the formal change control
process. should also spell out the general contents of trade study
reports, which form part of the decision support
packages (i.e., documentation submitted in conjunction
with formal reviews and change requests).
A second mechanism for controlling the trade
study process is the selection of the study team leaders
and members. Because doing trade studies is part art
and part science, the composition and experience of the
teams is an important determinant of the study's ultimate
usefulness. A useful technique to avoid premature focus
on a specific technical designs is to include in the study
team individu als with differing technology backgrounds.
Another mechanism is limiting the number of
alternatives that are to be carried through the study.
This number is usually determined by the time and
resources available to do the study because the work
required in defining additional alternatives and obtaining
the necessary data on them can be considerable.
However, focusing on too few or too similar alternatives
defeats the purpose of the trade study process.
A fourth mechanism for controlling the trade
study process can be exercised through the use (and
misuse) of models. Lastly, the choice of the selection
rule exerts a considerable influence on the results of the
trade study process. These last two issues are discussed
in Sections 5.1.2 and 5.1.3, respectively. 5.1.2 Using Models Models play important and diverse roles in
systems engineering. A model can be defined in several
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