Flow-shop problems with transportation delays

In a flow-shop problem with transportation delays additionally transportation delays (time-lags between the operations) are considered which arise when a job changes from one machine to another.

If job i changes from machine Mk to Mk+1, a job- and machine-dependent transportation delay t ik occurs. If these times are job-independent or machine-independent, we write t k or t i. Constant tranportation delays are denoted by t ik=T and t i {T 1,T 2} means that the transportation delays may take only two values.