不稳地滑动

A new discrete reaching law is presented to improve the reaching process of discrete exponential reaching law.The discrete-time variable structure control system designed by this reaching law can not only weaken the chattering and control the system state approach to zero diminishingly,but also keep the basic property of quasi-sliding mode which can cross the switching surface step by step.This method improves the reaching process and enhances the control quality of the control system.

为了改善离散指数趋近律的趋近过程，提出了一种新的趋近律，利用该趋近律设计的变结构控制器，不仅能够大幅度削弱抖振，使系统运动最终趋于原点不存在稳态振荡，而且能使系统的准滑动模态保持步步穿越切换面的基本属性，有效地改善了趋近过程，提高了控制品质。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。