Time-dependent identities

Me too (adding to the "identity complications")...

The discussion on "Tim Berners-Lee on the Semantic Web" gives me the opportunity to share some of my practical problems 
related to identities.

The triggers:

<snip id="1">
From: Alexander Johannesen <alexander.johannesen_at_nyob> 
Date: Fri, 30 Oct 2009 16:25:38 +1100

An example of this complexity is what semantics are
being applied at the time of use of the identifier. If we use the
un.org one, we must encompass the whole of UN's history in that
identifier, the ever-changing organisation. But if OCLC used theirs,
what semantics are within? The first era? The era after the cold war?
What it is now? This is about bias of identifiers.
</snip>

<snip id="2">
From: McDonald, Stephen <Steve.McDonald_at_nyob> 
Date: Fri, 30 Oct 2009 11:30:18 -0400

>  1. http://www.un.org/    (controlled by themselves)
>  2. http://id.oclc.org/org/d8445    (controlled by third-party)

How about a counter-example?  Try www.digital.com.  Digital Equipment
Corporation used to be very important.  You could have used
www.digital.com as a URI in the 90's, but the company went out of
business in 1998.  Today that address takes you to a portion of Hewlett
Packard's sales pages.  What do we use as a URI for nations and
organizations which don't exist any more?  Yes, you might expect the
United Nations to be a fairly stable site, but the USSR is gone,  a
number of countries in Europe are gone, hundreds of corporations are
gone, just since the beginning of the web era.  What about URI's for
subjects and concepts which don't have an associated organization which
can create a website?  For those cases the only possibility is a URI
created by some trusted organization, isn't it?
</snip>

<snip id="3">
From: Alexander Johannesen <alexander.johannesen_at_nyob> 
Date: Sat, 31 Oct 2009 07:56:22 +1100

In other words, identifiers will change with the times, and
www.digital.com would probably not be used anymore. This is why
distributed identity management services, such as www.subj3ct.com is
so important.
</snip>

NB. I'm concerned here only with "subject identifiers" (not with "resource identifiers/locators").

Case 1.

In our archaeological database we have (sometimes) to distinguish a geo-political entity (as a legal body) from its 
territory. E.g. The Habsburg Empire. Its territory was (very) time-dependent. So, when we locate a historical site we 
have to be very careful with the jurisdiction. How to identify conveniently the Habsburg Empire's territory ?

Besides: one identifier also for the "Austrian Empire" (i.e. ante 1867) and one for "Austria-Hungary (1867 - 1918) ? 
That is, 3 in totto ?

The case applies also to the birth/death places of persons in authority files, no ?

Case 2.

In our movable heritage database, we have - of course - to record the "is keeper of" in CRM terms) relationship between 
the object and the museum. But, for instance, the local authorities of my home town periodically change the 
organisation of the city museum. So from time to time, the art museum, the history museum and the ethnographic museum 
are merged in one museum, and after a couple of years, they are made autonomous again. Of course, always for a better 
management :-)

So we keep identifiers for 4 entities and try to keep track of the time spans for each.

The same case applies to the many reorganizations of our brave government. The ministries are combined and recombined 
many times. (Is that a Romanian peculiarity ? :-) What to identify ? Only the legal entities (the ministries) or also 
the "functions", say "central cultural administration" which sometimes is performed by the Ministry of Culture and 
sometimes by the Ministry of Education and Culture ?

Case 3 (not encountered in my current job).

We speak about:

a)	Wittgenstein I and Wittgenstein II;
b)	Marx and Young Marx;

not to mention Saul/Paul :-)


I do not have a decent solution to this kind of time-dependent identities. Any ideas ?

Dan


-----------------------------------------------------------------------
Dan Matei, director
CIMEC - Institutul de Memorie Culturala [Institute for Cultural Memory]
Piata Presei Libere nr. 1, CP 33-90
013701 București [Bucharest], Romania, www.cimec.ro
tel. (+4)021 317 90 72; fax (+4)021 317 90 64
www.cimec.ro