You can use DBA_HIST_ACTIVE_SESS_HISTORY to show details about the PeopleSoft operator id (OPRID) and which part of the online application they were in. I was just looking at a Query Manager issue and found that DBA_HIST_ACTIVE_SESS_HISTORY populated these three columns with PeopleSoft specific information like this:
CLIENT_ID=OPRID of user running query manager
Pretty cool. This is on HRMS 9.1 PeopleTools 8.50 Oracle database 220.127.116.11.