文章主要介绍代数式求值的几种常用方法。

This essay mainly introduces several evaluation methods of algebraic expression in common use.

接着，分析过程代数式，提出流程的评价指标；

Then, by analyzing the process algebra, the evaluation criterions and the approach of BPR are made;

文中导出了五次代数式缓和曲线的参数方程和曲线各元素的公式；

The parameter equation and the formula of each element of the curve are set up and compared with that of clothoid.