The present balanced two-layer sample rotation system is applicable only to the monthly survey with two-stagesample designs and with small primary sampling units.
目前的平衡两层次样本轮换模式只适用于一级单元规模较小时的两阶段抽样月度调查。
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Twostage search and sample match are emphasized in the paper. Then the final BOM is created on base of product model by knowledge and rule base which may decrease plenty of redundant information i…