Rescheduling a permutation flowshop problems under the arrival a new set of jobs

A set of jobs has been scheduled on a machine flowhop, but not yet processed, when a set of new jobs arrives. The problem of shop rescheduling on occurrence of an unforeseen disruption is addressed here. The decision maker needs to insert the new jobs into the existing schedule without excessively changing it. The practical solution requires satisfaction of two often conflicting goals. We propose a method to heuristically obtain a satisfying production schedule. The procedure involves two stages. In a first step, given a fixed order of jobs a conventional heuristic is proposed to successively assign the jobs to the machines. In a second one. the simulated annealing is applied to optimise the order of the jobs.