The majority of flow shop studies focused so far on permutation schedules, even though non-permutation schedules might offer better results at the expense however of additional computational effort. It is therefore crucial to determine whether the use of non-permutation schedules is justified by...

This paper addresses the problem of scheduling unit-time operations with integral and non-negative time delay considerations on a two-machine open-shop environment. The criterion to minimize is the makespan. Two well solvable cases and two approximation algorithms, with their worst-case...