Split scheduling with uniform setup times
We study a scheduling problem in which jobs may be split into parts, where the parts of a split job may be processed simultaneously on more than one machine. Each part of a job requires a setup time, however, on the machine where the job part is processed. During setup, a machine cannot process or set up any other job. We concentrate on the basic case in which setup times are job-, machine- and sequence-independent. Problems of this kind were encountered when modelling practical problems in planning dis- aster relief operations. Our main algorithmic result is a polynomial-time algorithm for minimising total completion time on two parallel identical machines. We argue, why the same problem with threemachines is not an easy extension of the two-machine case, leaving the complexity of this case as a tantalising open problem. We give a constant-factor approximation algorithm for the general case with any number of machines and a polynomial-time approximation scheme for a fixed number of machines. For the version with the objective to minimise total weighted completion time, we prove NP-hardness. Finally, we conclude with an overview of the state of the art for other split scheduling problems with job-, machine- and sequence-independent setup times.
|THEME||Logistics (theme 3)|
|Journal||Journal of Scheduling|
Schalekamp, F, Sitters, R.A, van der Ster, S.L, Stougie, L, Verdugo, V, & van Zuylen, A. (2015). Split scheduling with uniform setup times. Journal of Scheduling, 18, 119–129. doi:10.1007/s10951-014-0370-4