What is the difference between SUA and SAA? I would like to understand the difference between Special Use Airspace (SUA) and Special Activity Airspace (SAA). I found the following definitions.

Eurocontrol Lexicon for SUA (from FAA):


  Airspace of defined dimensions identified by an area on the surface of
  the earth wherein activities must be confined because of their nature
  and/or wherein limitations may be imposed upon aircraft operations
  that are not a part of those activities.


Eurocontrol Lexicon for SAA (from FAA):


  [U.S.] Any airspace with defined dimensions within the National
  Airspace System wherein limitations may be imposed upon aircraft
  operations. This airspace may be restricted areas, prohibited areas,
  military operations areas, air ATC assigned airspace, and any other
  designated airspace areas.


Can you please help me to understand what the difference is?
SAA is a project being undertaken to unify how SUA's (and ATCAA's) are defined, managed, and shared.


  
  [SAA will] define SUAs and ATCAAs in a consistent manner using an editing tool
  Use a Service Oriented Architecture (SOA) to distribute that data to interested users
  Manage the schedule and status of those airspaces through a SOA.
  


SAA is part of the System Wide Information Management (SWIM).

In short, SAA encompasses SUA, ATCAA, etc.



Source: SAA Modernization (.ppt file)