Security Realms are an Oracle Platform Security Services concept and bring together sets of users, groups, providers and so on for a WebLogic domain.

Explanation
Pull the table and column definition into the physical layer
Use the OBIEE "import metadata" wizard to pull the table and column definition into the physical layer. The wizard is used so that all of the column definitions do not need to be manually added into the physical layer.
Figure:

Note: The physical layer is the layer of the Logical Business Model where you define the physical data model of your data source. It contains information about the physical data sources.

Explanation
Dynamic Repository Variables:
You initialize dynamic repository variables in the same way as static variables, but the values are refreshed by data returned from queries. When defining a dynamic repository variable, you will create an initialization block or use a pre-existing one that contains a SQL query. You will also set up a schedule that the Oracle BI Server will follow to execute the query and periodically refresh the value of the variable.
Note: The value of a static repository value is initialized in the Variable dialog box. This value persists, and does not change until an Oracle BI Administrator decides to change it.

Explanation
Note 1: There are four types of variables that you can use:
Session
Repository
Presentation
Request
Note 2: Session Variables
A session variable is a variable that is initialized at login time for each user. When a user begins a session, the Oracle BI Server creates a new instance of a session variable and initializes it.
There are as many instances of a session variable as there are active sessions on the Oracle BI Server. Each instance of a session variable could be initialized to a different value.
There are two types of session variables:
System - A session variable that the Oracle BI Server and Oracle BI Presentation Services use for specific purposes.
System session variables have reserved names that cannot be used for other kinds of variables (such as static or dynamic repository variables and non-system session variables).
Non-system - A system variable that the administrator creates and names. For example, the administrator might create a SalesRegion non-system variable that initializes the name of a user's sales region.
The administrator creates non-system session variables using the Oracle BI Administration Tool.

Explanation
BIEE 11g Install High level Steps :
Software Required
1. Database (Oracle, IBM DB2 or MS-SQL)
2. Repository Creation Utility (RCU)
3. OBIEE 11g (11.1.1.3 is latest OBIEE as of 30 April 2011)
4. WebLogic 10.3.3 (Optional - Only required for 64 bit machine or IBM AIX)
5. JDK 1.6 64 bit (Optional - Only required for 64 bit machine)