We consider a scheduling problem where n jobs have to be carried out by m parallel identical machines. The attributes of a job j are a fixed start time sj, a fixed finish time fj, a resource requirement rj, and a value vj. Every machine owns R units of a renewable resource necessary to carry out jobs. A machine can process more than one job at a time, provided the resource consumption does not exceed R. The jobs must be processed in a non-preemptive way.Within this setting, we ask for a subset of jobs that can be feasibly scheduled with the maximum total value. For this strongly NP-hard problem, we first discuss an approximation result. Then, we propose a column generation scheme for the exact solution. Finally, we suggest some greedy heuristics and a restricted enumeration heuristic. All proposed algorithms are implemented and tested on a large set of randomly generated instances. It turns out that the column generation technique clearly outperforms the direct resolution of a natural compact formulation; the greedy algorithms produce good quality solutions in negligible time, whereas the restricted enumeration averages the performance of the greedy methods and the exact technique.

Optimal interval scheduling with a resource constraint

ANGELELLI, Enrico;BIANCHESSI, Nicola;FILIPPI, Carlo
2014-01-01

Abstract

We consider a scheduling problem where n jobs have to be carried out by m parallel identical machines. The attributes of a job j are a fixed start time sj, a fixed finish time fj, a resource requirement rj, and a value vj. Every machine owns R units of a renewable resource necessary to carry out jobs. A machine can process more than one job at a time, provided the resource consumption does not exceed R. The jobs must be processed in a non-preemptive way.Within this setting, we ask for a subset of jobs that can be feasibly scheduled with the maximum total value. For this strongly NP-hard problem, we first discuss an approximation result. Then, we propose a column generation scheme for the exact solution. Finally, we suggest some greedy heuristics and a restricted enumeration heuristic. All proposed algorithms are implemented and tested on a large set of randomly generated instances. It turns out that the column generation technique clearly outperforms the direct resolution of a natural compact formulation; the greedy algorithms produce good quality solutions in negligible time, whereas the restricted enumeration averages the performance of the greedy methods and the exact technique.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11379/371506
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