Time tradeoff transportation problems in case change of costs in certain intervals

Objective function has constant cofficient in most of transportation problems. However in problems which comes to face in real life, costs can not be constant. Also, it is fact that, in transportation problems time is important. [2] In this paper, we propose a solution with time-tradeoff in case change of costs in certain intervals, making transportation problems as a multiobjective transportation problem by order relations.