Logistics Optimization Of Self-organization Problem In Slab Warehouse And Load Planning Problem With Multi-steel Products

With the development of logistics technology in recent years, the efficiency of logistics operations becomes an effective means by improving the logistics operation management level to reduce the logistics cost and increase the enterprise competitiveness. The paper focuses on two practical problems above as the research contents, logistics self-organization optimization (LSO) problem in slab warehouse and load planning problem with multi-steel products. The research can promote the management level of production and logistic in steel making enterprises, and decrease the logistics operation cost. The paper mainly has done three parts of work, as follows:(1) Considering practical stacking and shuffling constraints, LSO problem is to cluster some slab clusters in slab warehouse.Decide the shuffling order and assign shuffled slabs to suitable storage positions, aiming to minimize the regularity penalty, the total number of shuffles and the overall crane traveling distances in the process. A concept named "regularity of slab warehouse" is introduced to capture the practicality of the solution and a regularity measure is presented. Adding the regularity measure as an additional objective function, this paper formulates a model for LSO problem in slab warehouse and use tabu search algorithm (TS) to solve it. The experimental results with practical data indicate that the improvement of regularity have been increased to36.5%in average compared with the solution obtained from the manual schedule.(2) Load planning problem is to assign many kinds of steel products to suitable stowage positions, considering the constraints of ship-loading standards and all kinds of steel products loading standards, aiming at minimize the port balance punishment and the number of lifting. For the specialization of the load planning problem, an integer programming model based on the practical requirement is established. The paper proposes a tabu search algorithm which is developed to obtain near-optimal solutions for this problem. In the process, a three-stage heuristic algorithm according to the specialty is proposed to obtain an initial solution. Based on this initial solution, a speed-up strategy and an improvement strategy are developed to accelerate the search procedure of the algorithm.The experimental results show that the proposed mathematical model and the tabu search algorithm can obtain satisfactory solutions in an allowable time and resolve the problem more effectively than currently manual method. (3) For the two problems described above in application, the LSO decision support system and the load planning optimization function module for many kinds of steel products have been designed and developed based on the algorithm mentioned above.