Theory of Computing Systems

, Volume 48, Issue 3, pp 577–613 | Cite as

Semi-Online Preemptive Scheduling: One Algorithm for All Variants

  • Tomáš Ebenlendr
  • Jiří SgallEmail author


We present a unified optimal semi-online algorithm for preemptive scheduling on uniformly related machines with the objective to minimize the makespan. This algorithm works for all types of semi-online restrictions, including the ones studied before, like sorted (decreasing) jobs, known sum of processing times, known maximal processing time, their combinations, and so on. Based on the analysis of this algorithm, we derive some global relations between various semi-online restrictions and tight bounds on the approximation ratios for a small number of machines.


Online algorithms Scheduling Preemption Linear program 


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Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Institute of MathematicsAS CR, Žitná 25Praha 1Czech Republic
  2. 2.Dept. of Applied Mathematics, Faculty of Mathematics and PhysicsCharles University, Malostranské nám. 25Praha 1Czech Republic

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