[Data-modeling] Adding a date/time CVT to organization members

[Jeff Prucher]

Jeff Thompson wrote:
>
> Jeff Prucher wrote:
> > Most properties on creative works -- author of a poem, 
> performer on a 
> > musical track, media of a painting, cover artist for an 
> edition of a 
> > book, director of a film, etc.
>  > Contents of a magazine issue
>  > Vineyard a vintage of wine's grapes were from
> 
> These properties are fixed because they are exactly what the 
> creator of the work says they are.  The author of a poem 
> publishes a book of poems and says "I'm the author", etc.  
> Unlike natural phenomena, or uncertain data, these 
> tautologically track human-generated information which is 
> what the information source says they are, hence they are 
> fixed.  And also arguably not that interesting for data mining.

Ah, it wasn't clear to me that you were only asking about CVTs on natural
phenomena and uncertain data, let alone those properties which might be
interesting for data-mining! That's a different kettle of fish entirely. 

> > Parent/Child/siblings (of a person or other organism)
> 
> If I may niggle, sibling is already a relation CVT, I assume 
> because it needs to be an N-way relation, not just a binary 
> relation which is all that a "normal" property can handle.

Niggling is pretty much always permitted. And the issue of what constitutes
parenthood has been discussed elsewhere recently, so these were perhaps bad
examples.

> > Maximum force of a (past) cyclone's winds
> 
> For measurements of natural phenomena like this, new 
> techniques improve the measurements even of past events.  I 
> understand that many just want Freebase to have the "one 
> correct approved consensus answer".  But this would be to 
> decide up front (even before Freebase leaves Alpha) that no 
> information needs to be captured about the refinement of 
> these measurements over time, or the honest disagreements of 
> different groups who use different measurement techniques.  
> Fortunately, I think the fate of Freebase will be better than 
> that, once those technical details are worked out.

I chose hurricane force precisely because I think it's unlikely that future
measurements will be able to more accurately determine an ephemeral
phenomenon like windspeed over a certain area and time (although the meaning
of different wind forces could easily change). But I completely agree that
the question of whether and how to record different understandings of
information is one that is well worth asking.

Jeff Prucher