为了使海运冷藏集装箱空箱调运的净收益最大化,在提供免费用箱的情况下,考虑订单收益、运输费用、在途库存费用、违约赔偿费用、租箱费用及买箱费用等因素,建立基于租买的海运冷藏空箱调运优化模型。由于冷藏箱造价高,利用普通空箱调运模型求解易造成只租不买使买箱决策失去意义。为避免此情况,引入自有箱系数、实际自有箱量等参数来控制租、买箱量,设置租买决策优先级,保证合理买箱与资源利用。运用整数规划求解,经算例计算结果显示,应优先考虑买箱,在购箱4次达到最低自有箱量后才开始租箱,此临界点出现在第2天购箱40 TEU后。周期中租买决策同时存在保证了买箱决策的存在意义,说明设置自有箱系数和最低自有箱量是合理的,模型是有效的,可应用于日常空箱调运业务中提高收益和得到空箱调运方案。
To maximize the repositioning yield of empty reefer container by sea transportation,the factors such as order revenue,transportation cost,in-transit inventory cost,punishment cost,rent cost and buy cost are considered,and an optimization model of repositioning in sea transportation for empty reefer on the basis of buy and rent for buy or rent is established,based on free container providing. As the high cost of refrigerated containers,the ordinary empty container repositioning model can easily lead to rent only,and this makes the decision to buy meaninglessly. To avoid this situation,the parameters include the volume of practical carrier's own container,the coefficient of carrier's own container,etc.,are introduced. They control the volume of buy and rent,and let buy and rent have the priority to avoid an unreasonable buy that will affect the normal operation. The model is solved by the integer programming optimizing and is demonstrated effectively by the calculated example. The results show that priority to buy,in the purchase of four times to reach theminimum amount before renting,the critical point in the second day after the purchase of 40 TEU.The existence of renting and buying in the cycle ensures the meaning of the decision of buying,therefore it is reasonable to set the coefficient of carrier's own container and the minimum carrier's own container. The model is applied to optimize daily container repositioning with a better revenue and plan.