中文摘要：

针对不完全语义条件下的非单调授权和权限判决问题进行形式化研究，提出了一种新的基于逻辑的非单调授权与访问控制框架——AACF。该框架通过扩展型分层逻辑程序表达授权与访问控制策略，支持不完全语义条件下的非单调授权、权限传播及冲突检测与消解等高级特性，此外，AACF的语义查询／权限判决算法的计算复杂度证明是多项式级的。因而，AACF比现有的访问控制框架具有更好的表达能力和计算特性，且具有更好的实用性。

英文摘要：

On the basis of researching formally on the complex security policies with nonmonotonic authorization and access control logic under incomplete context knowledge, this paper proposes a unified logic-based framework for nonmonotonic authorization and access control, called AACF. The AACF declares nonmonotonic authorization and access control logic through the extended and stratified logic program. With the proposed syntax structure in this paper, as a full-fledged authorization and access control framework, the AACF naturally possesses some advantages such as nonmonotonic authorization, authorization propagation, and conflict checking and resolution. Furthermore, the computational complexity of the semantic query evaluation （ i. e. , access control decision） algorithm of the AACF proved to be polynomial. Hence, the AACF has the better expression ability and computing characteristic than the existinz ones.