Operator->Junior Technician->Technician->Senior Technician & Specialist->Senior Specialist
Specialist 只能算中级技术水平的
到高级技术水平和专家的时候，就是
Junior Analyst->Analyst(等于 Senior Technician)->Senior Analyst (等于 Senior Specialist)->Expert->Senior Expert->Principal Expert
所以，其实应该没有 Intermediate 这个级别，而 Senior 反而是 Specialist 的一个“冠名”
从技能论
Operator -> Technician -> Specialist -> Analyst -> Expert
从管理论
Supervisor -> Team Manager -> Manager -> Senior Manager -> Director
