Annals of Operations Research

, Volume 26, Issue 1, pp 195–242 | Cite as

Approximation results in parallel machnies stochastic scheduling

  • Gideon Weiss
Multiple-Machine Scheduling


We consider scheduling a batch of jobs with stochastic processing times on parallel machines. We derive various new formulae for the expected flowtime and weighted flowtime under general scheduling rules. Smith's Rule, which orders job starts by decreasing ratio of weight to expected processing time provides a natural heuristic for this problem. We obtain a bound on the worst case difference between the expected weighted flow time under Smith's Rule and under an optimal policy. For a wide class of processing time distributions, this bound is of oderO(1) and does not increase with the number of jobs.


Processing Time Flow Time Time Distribution Optimal Policy Wide Class 
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Copyright information

© J.C. Baltzer AG, Scientific Publishing Company 1990

Authors and Affiliations

  • Gideon Weiss
    • 1
  1. 1.School of Industrial and Systems EngineeringGeorgia Institute of TechnologyAtlantaUSA

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