Queue Management in Mikrotik

I created a queue for each user with max download of 2M and upload of 512K. Now, I want to make these Queues automatically upon these parameters using scripts:

1- At any given time, one user can only use 2 Mbps for some specific period of time (e.g 120 to 180 seconds)
2- If user is using 2 Mbps for more then defined time then he will be limited to 100K/ for next 15 mins.

Please tell me some solution to achieve this goal … thanks

go to WIKI and search BURSTS