求翻译：由于模型(4-25)得到的最优加权系数向量W可能出现负分量，在实际应用中为了避免出现负权重，增加非负约束，得到模型(4-26)，从而求出非负最优加权系数。是什么意思？

Model (4-25) is the optimal weighting coefficient vector w may be a negative component in the practical application in order to avoid negative weights to increase the non-negative constraints, the model (4-26), which obtained the non-negative optimal weighting coefficients.

Because the model (4 - 25) is the best weighted coefficient vector W may have a negative component, in the actual application in order to avoid a negative weight, increase the number of non-negative constraints, model (4-26, and thus the non-negative optimal weighting factor.

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Because models (4-25) are optimally weighted coefficient vector w can occur a negative component, in practice in order to avoid negative weights, increased non-negative constraints, are models (4-26), so as to derive the optimal weighted non-negative coefficients.

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