Options for RDF Expression of Signal Data

Today's initial meeting of the Data Access Task Force was not a great 
success, since no one else showed up. (I'm interested in hearing 
(perhaps privately) why this was. Perhaps just too-short notice or 
otherwise poorly announced. Ten people confirmed that time slot in general.)

On the upside, I took the time to write up the issue, and maybe this is 
better done in writing anyway.

I'm starting with what basic graph shape to use to represent the n-ary 
relation inherent in the first signal.

See Options for RDF Expression of “Date Website First Archived” 
<https://docs.google.com/document/d/1f7hWNybjYcSFFRT48LcLdmH3KBBoYUeH-lKJypu6zQw/edit#heading=h.cn7f188h2acs>.  
Comments in email or the doc welcome. I think this might just come down 
to taste, but if there are any actual problems with any of the options 
(beyond zero), it would be good to highlight those before making a decision.

      -- Sandro