RBAC, Description Method, Looking for Examples

Hi All,

I'm looking for a concise method to define roles/permission structure for an organisation (rbac). I
ve already looked at some UML- and XML-based (e.g. secureUML)proposals, but none of them convinced me.

Can anybody recommend me a good (feasible) method for rbac description with some examples? Are there any common standards for rbac-defintion?

Thanks in advance,

Michael