Characters and States and GUIDs and descriptive data
Bob Morris
ram at CS.UMB.EDU
Wed Jan 25 10:30:52 CET 2006
I agree with Roger and had a brief skype argument ("skarg"?) with Kevin
about my position which moved me a little, but not much, closer to his.
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
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....
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 at LISTSERV.NHM.KU.EDU]*Im Auftrag von *Roger Hyam
>> *Gesendet:* Mittwoch, 25. Januar 2006 12:35
>> *An:* TDWG-GUID at 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 at tdwg.org
>> +44 1578 722782
>> -------------------------------------
>>
>>
>>
>
>
> --
>
> -------------------------------------
> Roger Hyam
> Technical Architect
> Taxonomic Databases Working Group
> -------------------------------------
> http://www.tdwg.org
> roger at tdwg.org
> +44 1578 722782
> -------------------------------------
>
--
Robert A. Morris
Professor of Computer Science
UMASS-Boston
ram at cs.umb.edu
http://www.cs.umb.edu/efg
http://www.cs.umb.edu/~ram
phone (+1)617 287 6466
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