IIn an open-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 Ml, a job- and
machine-dependent
transportation delay
t ikl
occurs. If these delays are job-independent or machine-independent, we write
t kl
or
t i.
Constant tranportation delays are denoted by
t ikl=T
and
t i
{T 1,T 2}
means that the transportation delays may take only two values.
The transportation delays may be symmetric, which is indicated by
t ikl=t ilk.