基于随机规划模型的弹性木材供应链网络优化

Cost optimization of resilient timber supply chain networks based on stochastic programming

为提高木材供应链网络的弹性和可靠性,揭示随机事件发生概率对木材供应链网络弹性的影响,针对木材供应链网络特点,综合运用概率分析和情景树分析法,对可能发生不确定性事件的木材供应链网络的优化问题进行研究。构建了考虑节点失效的弹性供应链网络随机规划模型,通过模型求解得出最优网络方案;引入供应链网络弹性评价指标对求解得到的供应链网络的弹性进行测度量化,并与确定性优化模型的结果进行比较;进行了随机事件发生概率的敏感性分析。基于实例的数值计算结果表明,在不发生随机事件的情景下,提出的模型所得解的网络总成本比确定性模型的解高出1.75%,而在其他情景下,前者的网络总成本均小于后者,就网络总成本的期望值而言,提出的模型比确定性模型低19.92%;同时,供材点失效概率及对应的供材量与供应链网络期望总成本成正比。因此,提出的随机规划模型是科学有效的,能作为弹性木材供应链网络优化的决策工具;构建木材供应链网络时,应避免所有供材点均受到同一随机事件影响,并尽可能降低供应量大的供材点发生失效的概率。

To increase the reliability of timber supply chain networks,we examined the probability of stochastic events on their resilience and where these events cause the failure of supply points.Considering the characteristics of the timber supply chain network,a stochastic programming model was proposed to address the scenario of node failure based on the results of a probability analysis and scenario tree.The results were compared with those of a deterministic model,and the resilience metrics of both networks were measured by the introduced resilience assessment indicator for the supply chain network.Finally,sensitivity analysis was conducted on the probabilities of the stochastic events and the expected total cost of the supply chain network.It was shown that although the proposed model resulted in a total cost that was 1.75%greater than that of the deterministic model with no stochastic events,the expected total costs derived by the former model were 19.92%lower.Furthermore,the probability of stochastic events causing failure of the supply points,and the scale of the corresponding supply volume,are directly proportional to the expected total cost.The proposed model was proven to be valid and effective;therefore,it can be used as a decision-making tool to ensure resilient timber supply chains.Meanwhile,it was shown that all supply points are also subject to the same stochastic events that should be avoided;further,the failure probability of supply points that provide the largest timber volumes should be limited when configuring a timber supply chain.