IKM stands for Integration Knowledge Module. IKM is one of the KM types supported in ODI.
It is for populating the data in the target database from the ODI staging area.
An ODI task consists of two phases: Loading Phase and Integration Phase. This concept is similar to BI Apps ETL concept of SDE and SIL. However, these two phases are WITHIN an ODI task.
If the source table and the target table are in the same database, you almost do not need LKM, only IKM is needed.
IKM typically is a single technology KM. In some cases, they are multiple technology KM.