derivative approach meaning in English

用导数图版进行试井解释的方法

Th ere are three approaches to deal with this problem , which are introduced and compared in this thesis : one is to throw off the absent observations ; second is to replace the absent observations with the average of other observations ; and third can be called first derivative approach
即观测值缺失问题，文章介绍并比较了三种处理这一问题的方法，分别是：去掉丢失观测值法、平均值替代法(零阶法)和一阶法。