The system includes a flexible and interactive approach for optimal selection of manufacturing partners. Within this design evaluation approach, the partner selection follows the generation and evaluation of manufacturing alternatives described above.
An explicit enumeration technique constructs from the process-plant pairs in the PPDS the alternative high-level process plans. Each plan is evaluated with respect to cost, quality, lead time, and the transportation cost between consecutive plants in the process plan. The performance of each process plan depends upon the cost, quality, and lead time for the component process-plant pairs. The transportation cost depends upon the location of the candidate manufacturing plants.
The designer may reduce the number of alternatives under consideration by excluding those alternatives that are dominated by some other alternative with respect to any combination of criteria and by excluding those alternatives that are inferior with respect to user-specified thresholds for one or more criteria.
The designer can sort the remaining alternatives on a linear combination of some criteria. The designer provides a weight for each performance criterion, and the weighted combination of the criteria forms the new performance criterion. For example, these weights allow the designer to convert all criteria to dollars or to give relative weights to the criteria.
Alternatively, the designer can specify preferences
in the form of natural language expressions
about the importance of each performance attribute (cost, quality, lead time).
The system combines these preferences using Fuzzy-AHP,
a fuzzy extension of AHP [30,31],
with existing data (from industrial surveys
and statistical analysis) to re-emphasize attribute priorities.
These redefined attribute priorities reflect the specific needs of the
firm for this product.
In the Fuzzy-AHP procedure, the pairwise comparisons
in the judgment matrix are fuzzy numbers that are modified
by the designer's emphasis.
Using fuzzy arithmetic and 
-cuts, the procedure
calculates a sequence of weight vectors that will be used to
combine the process plan's scores on each attribute.
The procedure calculates a corresponding set of scores
and determines one composite score that is the average of these fuzzy scores.
The high-level process planning and partner selection modules produce many types of feedback for the designer. The feasibility and manufacturability assessment routines give the designer suggestions on the specific factors that affect the cost, quality, and lead time of the product design. The partner selection module combines the results of these stages to estimate the overall cost, quality, and lead time of the product design. In addition, the partner selection module allows the designer to identify the superior manufacturing processes, which may affect the detailed product design, and the superior candidate manufacturing plants, which may become partners in the virtual enterprise.