n.稀疏；稀少

Because the data it used was not users' rating but users' browse route, the problem of data sparseness and initial rating was resolved. 由于数据不是简单的用户评分，而是用户浏览网页的路径，这样就解决了数据稀疏问题和最初评价问题。

Based on the clustering method, the mixing matrix was first estimated by a new potential function using the sparseness of sources. 首先，利用变换后信源的稀疏特征，采用一新的势函数通过聚类算法估计混叠矩阵。