sparsity

collaborative filtering is becoming a popular technique for reducing information overload. however, most of current collaborative filtering algorithms have several major limitations: accuracy, data sparsity and cold start problem.

协同过滤是一种常用的减少信息过载的技术，已经成为了个性化推荐系统的一种主要工具，然而现有大多数协同过滤算法存在着几个主要问题：精确性，数据稀疏和冷启动问题。

its sparsity and spissitude is in good order, just like the arrangement by the genius.

这种稀疏和密集的分布错落有序，就如同聪明人设计出来的一样。

This overstress phenomenon is related to stress hysteresis of debris flow which consists of shear sparsity at beginning of deformation from viscous drag and internal friction from mutual extrusion of granulae with different sizes.

这种应力过冲特征，与由粘性介质阻力形变初期的剪切稀化和高浓度粗细颗粒相互挤压的内摩擦力共同组成的泥石流体的应力滞后特性（抗剪强度）有关。