Abstract: The relations of the dependencies are found and formalized. The scope of impact raised by requirements change is confirmed by backtracing algorithm, and the impact is quantitively described by using impact factor. Then the algorithm is presented to evaluate the impact of this quantitive description. An example of case study shows the feasibility of this evaluation algorithm.

Key words: Requirement change, Dependency, Evaluation algorithm

摘要： 通过对需求依赖关系的分析与归纳，给出了需求依赖关系的依赖形式；采用回溯法来搜索和界定需求变更的影响范围，给出了变更影响的量化方法；从需求依赖关系的视角，设计了一个可以量化评估需求变更影响的算法。通过一个“样例学习”的例子，展现了该评估算法的稳定性。

关键词: 需求变更, 依赖关系, 评估算法