Journal of the Operational Research Society

, Volume 50, Issue 7, pp 756–764 | Cite as

Two-machine open shop scheduling with special transportation times

Technical Note


The paper considers a problem of scheduling n jobs in a two-machine open shop to minimise the makespan, provided that preemption is not allowed and the interstage transportation times are involved. In general, this problem is known to be NP-hard. We present a linear time algorithm that finds an optimal schedule if no transportation time exceeds the smallest of the processing times. We also describe an algorithm that creates a heuristic solution to the problem with job-independent transportation times. Our algorithm provides a worst-case performance ratio of 8/5 if the transportation time of a job depends on the assigned processing route. The ratio reduces to 3/2 if all transportation times are equal.


open shop scheduling transportation time two machines 


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Copyright information

© Operational Research Society 1999

Authors and Affiliations

  1. 1.University of Tizi-OuzouTizi-OuzouAlgeria
  2. 2.University of GreenwichLondon

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