As a methodology, UML/UP have two defects in requirement specification:the requirement elicitation and specification capability is not so powerful;

UP作为方法学，在需求方面存在两大不足：需求表达能力不强；

youdao

Describes the principle of use case model technology, discusses the requirement elicitation based on use case modeling, sums up some experience and understanding from practice.

在描述用例建模技术原理的基础上，重点讨论了基于用例建模的需求获取，并对一些经验和体会加以总结。

youdao

A method, in light of the characteristics of requirement elicitation based on the ontology, was offered here to merge, associate, and align domain requirement models with the root domain ontology.

该方法通过领域的根本体对领域不同的需求模型进行合并、关联和修正等操作。

youdao