Multi-resource shop scheduling with resource flexibility

The shop scheduling problem tackled in this paper integrates many features that can be found in practical settings. Every operation may need several resources to be performed, and furthermore, a resource may be selected in a given set of candidates resources. Finally, we also consider that an operation may have more than one predecessor and/or more than one successor on the routing. The problem is then to both assign operations to resources and sequence operations on the resources, in order to minimize the maximum completion time. A disjunctive graph representation of this problem is presented and a connected neighborhood structure is proposed. The latter can be used to derive a local search algorithm such as tabu search. Finally, some numerical experiments are presented and discussed.