Coordinated Machine Scheduling and Conveyance Problems of a Steel Works

The objective to study on is to minimize the overall cost of both production and in-situ conveyance that should not be ignored in the supply chain scheduling of a steel works.Limited capacity of transporters and limited waiting time of jobs before their processing should be taken into account.To simplify the problem,it is assumed that the machine to use is just a single machine on which the job to be processed has limited time to await with unlimited number of transporters ready for use.Thus,the objective function for scheduling becomes the conventional scheduling function plus conveyance cost.For different objective function,the problem of scheduling is proved strongly NP-hard if a job has limited waiting time before processed on a single machine.As to the solvable case that the capacity of transporters is limited,some polynomial time algorithms are given.