在现实的采购运作中，双源采购和后备生产是两种最常见的风险应对策略。本文在考虑信息更新的情况下，探讨了一个两阶段动态采购决策模型：第一阶段，制造商向存在供应风险的一个或两个主供应商订货；第二阶段，制造商根据主供应商风险信息的更新，决定是否向供应可靠但价格较高的后备供应商订货。本文得到了两阶段的最优采购策略，分析发现，当固定采购成本较低时：若潜在市场需求较小，双源采购将排斥后备生产；若潜在市场需求较大，双源采购和后备生产共存；若潜在市场需求适中，后备生产可能排斥双源采购，两者也可能共存。特别地，在潜在市场需求适中时，可靠性改进概率的增大或后备供应商生产成本的降低，将使后备生产趋于排斥双源采购；反之，可靠性改进概率的减小、固定采购成本的降低或后备生产成本的增加，将使两者趋于共存。
Dual sourcing and backup production are two operational strategies that firms most commonly use to mitigate supply risk. In this paper, the updating of information on supplier reliability is considered, and the firm strategic use of dual sourcing and backup options in two stages are examined. In the first stage the firm orders from one or two unreliable primary suppliers, and then in the second stage decides whether to order from a backup supplier with complete reliability contingent on the updated information. The optimal sourcing and ordering decisions of the firm are completely characterized in the two stages. When there is no backup option, the firm prefers dual sourcing to single sourcing if the fixed procurement cost is low. When there is the backup option, the optimal procurement strategy depends on the market potential. Under low fixed procurement cost, the results show that when the market potential is small, dual sourcing excludes backup options from the sourcing strategy due to the high cost of backup; when the market potential is large, dual sourcing and backup production coexist to satisfy the high demand; when the market potential is moderate, dual sourcing may be excluded by backup production, and the two may also contingently coexist. Furthermore, when the market potential is moderate, the firm tends to exercise the backup option rather than using dual sourcing, especially when the probability of reliability improvement increases or the backup cost decreases. Contingent coexistence of both dual sourcing and backup production becomes more likely when reliability improvement probability decreases, fixed procurement cost decreases or backup cost increases. In summary, the choice between exclusive and coexistence of dual sourcing and backup production balances the profit loss from over ordering, the fixed procurement cost and the additional production cost of backup.
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