更好的模型可能是使用以1天和1年为周期的正弦和余弦函数。
A better model might be to use sine and cosine functions with a periods of 1 day and 1 year. This we can do by changing the formula to.
提出了同轴度误差的数学模型，其中给出一种高效的优化方法一余弦移位相加法。
The mathematic model of concentricity error and a advanced optimal method - "cosine shift plus" are put forward.
针对基于向量夹角余弦准则下组合预测模型，研究它的基本结构特征。
In this paper, the basic structural characteristics of combination forecasting model is studied under the criterion of vectorial Angle cosine.
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