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xs6525(未真实交易用户) 发表于 2012-5-20 14:31:39

太贵了吧

322楼

林烨(真实交易用户) 发表于 2012-6-16 00:35:01

谢谢分享

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coveychen(未真实交易用户) 发表于 2012-7-3 15:22:22

神啊这么贵结果据说还打不开黑不黑

宠辱不惊看庭前花开花落
去留无意望天上云卷云舒

324楼

tilapia(未真实交易用户) 发表于 2012-7-4 23:36:13

顺便在这问个问题，有人能帮忙解答一下吗？
The replenishment lead time is different from the standard time period (For example, weekly or monthly) used to collect demand data. We need a way to compute σm from σ1, where σ1 refers to the standard deviation of demand over the standard time period. For example, the lead time is three weeks and the standard time period is one week. Consider the lead time demands as the sum of three weekly random demands. Then if the weekly demands are independent, the variances of the sum equals to the sum of the variances:

(σm)^2=(σ1)^2+(σ1)^2+(σ1)^2=3(σ1)^2

So that: σm=3^(1/2)σ1

If L is the length of lead time, then general formula is:

σL=L^(1/2)σ1