Started with the conception of equipment renewal, several equipment renewal methods are introduced briefly, including lowest-feemethod, MAPI method and economic lifetime method.
从装备更新的概念入手，简要介绍了几种装备更新的分析方法，如最低费用法、MAPI法、经济寿命法等。
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From a personal standpoint I would be willing to pay a small monthly fee for unlimited download access and the ability to continue using BitTorrent websites - as I prefer that method of downloading.
With the modify model of ZTD we can apply a new method for ZTD calculation of none auxiliary stations which can decrease the fee of the network and calculated time of GPS ZTD.