[Data-modeling] Historical currency

[Danny Hillis]

Another solution to the time span problem would be pair the currency  
with an Historic Period, the time equivalent of Location. Thus the  
currency could be in use during period of Roman Occupation, the Reign  
of Henry the Eighth,  the Civil War or the vaguely-bounded Present.
-Danny

( Due to an injury I am typing with one hand, so please excuse the  
cryptic nature of my message. If there is any confusion, just call me  
at 818 545-1401)






On Apr 1, 2008, at 4:36 PM, Jeff Prucher wrote:
>
>
> > -----Original Message-----
> > From: data-modeling-bounces at freebase.com
> > [mailto:data-modeling-bounces at freebase.com] On Behalf Of Jeff  
> Thompson
> > Sent: Monday, March 31, 2008 11:59 PM
> > To: Freebase data modeling mailing list
> > Subject: Re: [Data-modeling] Historical currency
> >
> > Christopher R. Maden wrote:
> > > we should be
> > > able to capture the distinction without overcomplicating
> > the model -
> > > or indeed without knowing the dates involved. This last point is a
> > > problem with time-valued properties; if I know that
> > something was true
> > > in the past but I don't know *when* it stopped being true,
> > I can either lie (excuse me, "guess" - er, "estimate") or
> > make an assertion that appears to be currently true; neither is  
> ideal.
> >
> > The problem assumes a property can only be true over one
> > continuous time span.  But think of a country occupied by the
> > Romans, then beaten back, then occupied again, then finally
> > defeated.  What is time-value for the property that says the
> > country has Roman currency?  Time-valued properties need to
> > allow for multiple periods.  So in your case above, if you
> > know that something was true in the past, even for a day,
> > then assert that period.  If someone else can show that it
> > was true for some period after that, then that period of
> > validity can be added too.
>
> I don't think Chris was suggesting that a time-valued currency  
> property
> would be unique. The problem is not with representing values that  
> change
> over time, even if they change back and forth; that's very simple and
> implicit in most time-valued properties I can think of (Grover  
> Cleveland's
> two non-contiguous terms as U.S. President are an example of this  
> that I
> know is in the graph). The problem is making assertions about data  
> for which
> we have no time-value information but which is modeled as being time- 
> valued.
> So it's one thing to say a country had Roman currency from M to N,  
> then its
> own currency from O to P, then Roman again from Q to R, and then its  
> own
> currency starting again at S. This is good, clear data. It's another  
> thing
> entirely to say that a country has or had Roman currency and its own
> currency; without dates, you have no way of knowing which (if any)  
> is the
> current currency and which are historical. Since this is the quality  
> of data
> that we currently have (i.e., I think Chris is trying to avoid this  
> issue by
> making the properties binary. So we can assert that certain  
> currencies are
> current, and that certain currencies have been used at a time or  
> times in
> the past but are no longer used.
>
>
>
> Jeff Prucher
>
>
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