Define object level security? | OBIEE

In general, there two types of object level security, they are:
Web level and repository level
Web level:
Here, security is given for the objects which are stored in the web catalog of Siebel analytics such as folder, dashboards pages and reports you view objects for which you are given authorization. Example: manager at the middle level is not given access to dashboard which includes summary information for complete department.
Repository level:
The repository level security is provided in the presentation level by denying or given permission to the users to see specific column or table.