Jobshop scheduling problems with fuzzy or flexible durations

The literature dealing with production scheduling assumes all the time parameters to be well-known and precisely defined. This strong assumption prevents the main results in scheduling from being applied in industrial environment. Either the durations are unknown because of unexpected events, or they can be flexible and tunable with some effects on the operations quality. Very few studies are concerned with uncertainties, although the imprecision in the duration is very critical for all the optimization procedures. But it can be shown that fuzzy sets may help to cope with both kinds of uncertainties