2011 Volume 97 Issue 6 Pages 352-359
Nowadays steel manufacturing pays a critical attention to on-time delivery and inventory reduction. In our study, we propose a heuristic algorithm to solve the hybrid flow shop scheduling problem (HFSP) considering reducing total tardiness and inventory time. In order to achieve a feasible solution in limited computational time, the algorithm is based on Three-zone Buffer Management (TZBM) approach. TZBM approach combines the Drum Buffer Rope (DBR) method proposed in theory of constraints (TOC), with a contract net protocol in multi-agent system (MAS). The effectiveness of the proposed algorithm is shown by simulation results comparing with the results obtained by a Tabu search (TS) algorithm. In the production field, a shipment buffer is set between the due date and the shipping time in order to avoid possible late shipment. The size of shipment buffer is always decided according to the experience of a system operator who has responsibility to draw up a production schedule. Wherein, an operator needs to take a decision considering trade-off between on-time delivery and inventory reduction. Therefore, a new interactive decision support system is proposed which is based on the two-stage TZBM approach. The operator needs to make his/her judgment whether an optimal solution shown by the system is preferable or not, then to change the trade-off between the two conflicting objectives. The system needs to compute another optimal solution according to judgment given by the operator. Under the result of numerical experiments, to integrate the experience of operators with the computational intelligence of systems proves to be an effective scheduling method.
