Discrete element method is used to analyze the roof stability in accordance with the variation of its loading, rock frictional Angle, bolt spacing, rock properties and bolt orientation.
采用离散单元法，分析了当荷载、岩体的摩擦角、锚杆间距、锚杆方向和岩体的性质变化时，顶板的稳定性。
2
As one of the branches of statistics, time series analysis focuses on the variation characters and trend of discrete ordered data series mainly.
时间序列分析是统计学的分支之一，它的研究对象是离散有序数列的变化特征和变化趋势。
3
Start-up process is a kind of complicated dynamic variation system, which exists not only continuous dynamic variables but also gone with discrete logic variables.