The paper raises and proves an essential condition of volumetric property of nonnegative secondary estimation of deviation and variance in linear model.
文中给出并证明了在椭球约束条件下线性模型中，误差方差的非负二次估计的可容许性问题的一个必要条件。
Detecting rate of the secondary gauge along with the variance of water quantity is analyzed, therefore, leakage can be identified. This method can reduce water consumption.
经过对二级表监测率随用水量变化的情况以及其它测试数据的科学分析，可判断漏水点存在与否，以节约水资源，达到节能降耗的目的。
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