提出一套形式化地描述时间特性的模型，使之能够描述带时间特性的授权约束。

A formal model is proposed to describe time character of constraint in this paper.

youdao

提出一套形式化地描述时间特性的模型，使之能够描述带时间特性的授权约束。

A formal model is proposed to describe time character of constraint in this paper.

youdao