PBAC, in the context of OMII InformationSecurity aspects, stands for ProcessBasedAccessControl. Other Google matches are "Policy Based AC" and "Provision Based AC", and there is also a term of "Probe Based Admission Control" that is used in the vicinity of the above context.
Earlier I was looking to understand how PBAC links to PolicyBasedManagement?, and how SecurityManagement intersects with SystemsManagement intersects with SoaSystemsManagement, MessageLevelSecurity etc.
Could be a CategorySecurity CategorySoa if more information comes out from SelfTalk or heaven forbid, a CollaborateForSuccess case.
An irrelevant link on "PBAC OMII" (Trivial Google search link, 1st match at http://www.omii.ac.uk/docs/2.0.0/omii_2_user_guide/services/omii_services_do_for_me.htm ) . Other MarkeTectures exist.