Re: Characters and States and GUIDs and descriptive data

25 Jan 2006

      Continuous characters might be something like this:
mytaxa:rose myterms:has _:att1 .
_:att1 rdf:type myterms:leaf .
_:att1 myterms:length _.att2
_:att2 rdf:value "22" .
_:att2 rdf:type myterms:oneMilPrecisionMeasurement .
The blank nodes in this mean it would probably be easier to read in XML
syntax.  I am sure there are vocabularies out there that could be used
for measurement stuff.
Do we need GUIDs for the resources in this or can we just do this with
old fashioned URIs? Who else used LSIDs or DOIs to do this kind of
thing? I just seem to see the use of namespace type URIs.
Roger
Ricardo Scachetti Pereira wrote:
...
Bob Morris wrote:
...
I think the most debilitating issue is that  GUIDs could only go on
categorical characters (== 'enumerated' to informaticists), and maybe
not even all of those. Absent a compelling reason, I hate to see an
abstraction that can only be applied to certain classes of what one
needs to talk
Couldn't you describe (to machines), the semantics of continuous
variables (or characters) in an ontology? Still, you won't be able to
assign GUIDs to continuous characters, but does it make sense to do it?
Wouldn't it be enough to describe the character and the range of values
it can assume? I guess there must be various ontologies that model
continuous variables (measurements for example) out there.
...
I am about to leave for Costa Rica but will continue participating in
such discussion as develops. I BEG, PLEAD, and IMPLORE that it be
memorialized on a wiki. It is really hopeless to follow an email
argument 6 months later....
You got it.
Have a nice trip, Bob!
...
Bob
Roger Hyam wrote:
...
Hi Robert,
Characters and States are the building blocks of the DEscription
Language for TAxonomy (DELTA). This has been around since the 1980s and
is being updated as Structure of Descriptive Data (SDD) - which I am
fairly ignorant on but believe has the same basic notion of characters
and states but one of the SDD guys would be better talking about that.
The DELTA home page is here: http://biodiversity.bio.uno.edu/delta/ but
seems to be down now. There is plenty on Google.
The SDD wiki here: http://wiki.cs.umb.edu/twiki/bin/view/SDD/WebHome
(SDD also uses class in a different sense.)
I think what I was saying is that the usage of classes and states does
not fit well with the use of a thesaurus like approach as the
'traditional' meaning of these things is not clear in an open world and
that this may not just be a problem with DELTA style data but we may
come across it in other places.
Hope this clarifies things.
Roger
Robert Huber wrote:
...
Dear Roger,
I could not reall yunderstand what you and Kevin mean by Characters
and States.
From the example you gave, it appears to be  like  classes
(character) and attributes (states) or you want to assign GUIDs to
something like Thesaurus entries? But maybe I completely misunderstood
what you meant..
best regards,Robert
-----Ursprüngliche Nachricht-----
*Von:* Taxonomic Databases Working Group GUID Project
[mailto:TDWG-GUID@LISTSERV.NHM.KU.EDU]*Im Auftrag von *Roger Hyam
*Gesendet:* Mittwoch, 25. Januar 2006 12:35
*An:* TDWG-GUID@LISTSERV.NHM.KU.EDU
*Betreff:* Characters and States and GUIDs and descriptive data

Kevin mentioning Characters and States and GUIDs got me thinking
and I was wondering if we could cover something along these lines
before the meeting. Please excuse me if this has been dealt with
on the list. I will use a Delta type illustration to my point.
This may not apply to SDD so much - apologies if it doesn't but I
am trying to get at a general point. My comments may be more
general to GUIDs though...

When we are dealing with GUIDs we are talking in an Open World
model as opposed to a Closed World model. If I search Google (open
world) and don't find something it isn't because it doesn't exist
- it may exist but not be found for a host of reasons. If I search
my local SQL DB (closed world) and I don't find something then I
can safely assume it isn't there. (This may be a naive description
of Open vs Close worlds but it illustrates the point).

Taking this to the Characters/States model. We have a character
that looks like this:

Flower Colour (GUID_c01)
- red (GUID_s01)
- white (GUID_s02)
- yellow (GUID_s03)

And I score a taxon as  "Rose *has* flower colour red". If I have
given GUIDs to the states then I don't need to use the GUID for
the character. "Rose has s01" is fine as the character is implied.

Can we assume from this statement that my rose does not have white
or yellow flowers? Yes - but only if it is a closed world and we
know that the character never changes (or hasn't changed since the
date of the assertion). If the choice when scoring had been:

Flower Colour (GUID_c01)
- red (GUID_s01)
- white (GUID_s02)
- yellow (GUID_s03)
- dark pink (GUID_s99)

I may have chosen "Rose has s99" of "Rose has s99 and s01" but I
simply didn't have that choice before.

So the thing that is troubling me is that Character/State uses a
closed world model where not finding something implies that it
doesn't have that attribute. In an open world system one can only
draw conclusions from presence not absence. We could give GUIDs to
characters and states but it doesn't get us very far as it doesn't
permit us to re-use or extend them in a simple way. (sure you
could build an inheritance model for characters and states but
this rapidly becomes a complete ontology language of which there
are a few already available!).

My gut feeling is that in the long term the Character/State model
doesn't transfer well into an open world model. I suspect this
problem may occur in other descriptive areas where the existing
model specifies noun-adjective pairs that I don't have experience
of. Perhaps we could explore this a little. Perhaps my guts need
straightening out!

Your thoughts greatly appreciated.

Roger

--

-------------------------------------
 Roger Hyam
 Technical Architect
 Taxonomic Databases Working Group
-------------------------------------
 http://www.tdwg.org
 roger@tdwg.org
 +44 1578 722782
-------------------------------------

--

Roger Hyam
Technical Architect
Taxonomic Databases Working Group

http://www.tdwg.org
roger@tdwg.org
+44 1578 722782
--
Robert A. Morris
Professor of Computer Science
UMASS-Boston
ram@cs.umb.edu
http://www.cs.umb.edu/efg
http://www.cs.umb.edu/~ram
phone (+1)617 287 6466
--
-------------------------------------
 Roger Hyam
 Technical Architect
 Taxonomic Databases Working Group
-------------------------------------
 http://www.tdwg.org
 roger@tdwg.org
 +44 1578 722782
-------------------------------------

Roger Hyam

+44 1578 722782

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