In the beginning, the city had a name, Urm, a smell (strong), and scarce anything else.

起初，这座城市有一个名字，Urm，有气味(很重)，但是没有其他任何东西。

It explains a user role mapping (URM) method, designs and implements a rule engine which has been adopted by a real access control system.

描述了一种用户角色映射(urm)的方法，设计实现一种规则引擎，并将其应用于实际访问控制系统。