价格不确定条件下多阶段一次性采购策略研究

Research on the Optimal Strategy for a Multistage One-time Procurement when Price Distribution is Discrete and Uncertain

价格不确定条件下多阶段一次性采购的最低成本支出,需要采购决策人员对当前阶段的报价以及未来阶段可能的报价进行科学地预测与比较,决定当期采购还是推迟采购。针对每阶段由高价、中间价、低价分别按不变概率出现组成的离散型不确定价格结构,应用动态规划模型通过逆向求解法,并考虑三种价格之间的关系,运用归纳法对N阶段最优采购策略进行探讨。研究结果得出,当三种价格期望值低于中间价,以及高于中间价时多阶段一次性采购的最优策略。此最优策略通用性强,具有较高的实践意义。

The optimal cost of multistage one-time procurement with uncertain prices depends on the purchasing manager＇s scientific prediction and comparison on the present price and future might-be price to decide whether buy now or delay to the next period. A discrete-stochastic price structure is studied which is composed of high price, median price and low price in each period of quotation with unchangeable probability. Using dynamic pro-gramming model as well as considering the relations of the three different prices, the optimal purchase strategies for N-periods are under discussed. The results show that, there exist general optimal strategies for multistage one-time procurement when the expectations of the three prices are below or above the median price. It possesses high practical significance.