Answer: A replenishment policy consists of decisions regarding when to reorder and how much to reorder. These decisions determine the cycle and safety inventories along with the fr and the CSL. There are several forms that replenishment policies may take. We restrict attention to two instances:
1. Continuous review: Inventory is continuously tracked and an order for a lot
size Q is placed when the inventory declines to the reorder point (ROP). The time between orders may fluctuate given variable demand. When using a continuous review policy, a manager has to account only for the uncertainty of demand during the lead time (L).
2. Periodic review: Inventory status is checked at regular periodic intervals and an order is placed to raise the inventory level to a specified threshold. In this case, the time between orders is fixed. The size of each order, however, can fluctuate given variable demand. Periodic review replenishment policies require more safety inventory than continuous review policies for the same lead time and level of product availability, because the safety inventory has to cover for
demand uncertainty over the lead time and the review interval (L + T). Periodic review policies are simpler to implement for retailers because they do not require that the retailer have the capability of continuously monitoring inventory. Given that higher uncertainty must be accounted for, periodic review policies will require a higher level of safety inventory. Difficulty: Moderate
答：补货政策包括决定何时重新排序和多少排序。这些决定的周期、安全库存随着神父和俊。有几种形式，补货政策可能。我们限制注意实例：
1。连续审查：库存不断跟踪和订购了很多大小是当库存下降到订货点（人事）。之间的时间可能波动不同需求订单。当使用一个不断审查政策，经理必须考虑只对需求的不确定性在前置时间（我）。
2。定期审查：库存检查周期的间隔和顺序放置提高库存水平到一个指定的阈值。在这种情况下，之间的时间是固定的订单。各大小订单，然而，由于需求波动变。定期审查补充政策需要更多的安全库存连续审查政策为同一时间和的产品可用性水平，因为安全库存已经覆盖需求不确定性的时间和审查间隔（1 +）。定期审查政策是简单的执行，因为他们不需要为零售商，零售商有能力不断监测库存。鉴于较高的不确定性都必须加以核算，定期审查政策将需要更高水平的安全库存。 难度：中等
4.
Explain the impact of supplier lead time on safety inventory.
Answer: The required safety inventory increases with an increase in the lead time and the standard deviation of periodic demand. Reducing the supplier lead time (L) will reduce the need for safety inventory. If lead time decreases by a factor of k, the required safety inventory decreases by a factor of ?k. The only caveat here
is that reducing the supplier lead time requires significant effort from the supplier, while reduction in safety inventory occurs at the retailer. Thus it is important for the retailer to share some of the resulting benefits. A reduction in supply
uncertainty can help dramatically reduce safety inventory required without hurting product availability.
Often, safety inventory calculations in practice do not include any measure of supply uncertainty, resulting in levels that may be lower than required. This hurts product availability. Difficulty: Moderate
答：所要求的安全库存量的增加而增加的时间和标准差的周期性需求。减少供应商的时间（我）将减少需要安全库存。如果时间下降的一个因素，需要安全库存减少的一个因素?K唯一需要注意的是，减少供应商的时间需要很大的努力从供应商，同时减少安全库存量发生在零售商。因此，重要的是零售商共享一些由此产生的效益。减少供应的不确定性可以大大减少所需的安全库存不损害产品的可用性。 通常，安全库存计算在实践中不包括任何衡量供应的不确定性，导致水平可能低于要求。这伤害了产品的可用性。 难度：中等