Rule-Based approach is adopted in case modification of the system. Algorithms are worked out to decide feature whose process needs to be deleted and whose process needs to be added.

• 确定了本系统实例修改采用基于规则的方法,给出了确定工艺需要删除的特征和工艺需要增加的特征的算法,并介绍了如何实现工艺实例的修改。