中文摘要：

结合传统的基于角色访问控制（RBAC）模型和授权管理的实际需求，文章提出了一种在时间和空间维度约束下的分级授权模式，该模式授权粒度中等，可灵活地按角色、岗位、部门和用户实施权限分配操作。

英文摘要：

Considering the characteristic of original RBAC model and the actual demand of authorization management, a kind of multi-level authorization mode confined by time and space dimension is presented, which is of moderate granularity and capable of assigning permissions according to role, post, department and user.