[foaf-dev] Previous relations and predicate weightings

Hi,

I'm one of the devs on my current project, SerenA (
http://www.serena.ac.uk ). For the last 6 months, we have been
building an RDF store representative of our users.

I am responsible for mapping user profile information into the FOAF
Ontology, and I have 2 questions to ask:
1 - Capturing previous and current work status.

i.e. I may have once worked for the CIA, but I currently work on the
SerenA project. How would I capture that using FOAF? For the latter,
perhaps:
http://www.example.com/Rob_Stewart <foaf:Project> http://www.example.com/serena
or
http://www.example.com/Rob_Stewart <foaf:Organization>
http://www.example.com/serena

But... how would I capture that I worked for the CIA between 2004 and
2006, say ? (and should I be using Organization or Project ? )
-------------------
2 - Strength of the foaf:knows predicate
How would I capture the different levels of my foaf:know
relationships? Say, I shared an office with someone called Tim, and I
stumbled across Alison once a month in the coffee room. I know both,
but I am wanting to know how you would represent this with FOAF? I
*do* want the foaf:knows predicate for both objects, but it's not
telling the full story... ?

Regards,

--
Rob