CPU % usage per user

1- Would anyone please confirm if "database resource manage" comes only with Enterprise Edition or can run on Standard Edition ?

2- How can I set a profile for a user in a way that he/she uses only a percentage of the CPU:
In other word: I need to have 3 differents profiles for 3 differents users and need to limit each to cpu usage:

user1 (profile1): 50 % CPU Usage
user2 (profile2): 30 % CPU Usage
user2 (profile3): 20 % CPU Usage

Thanks alot.

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