Characters and States and GUIDs and descriptive data
Roger Hyam
roger at TDWG.ORG
Wed Jan 25 16:40:15 CET 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 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
>>
>
--
-------------------------------------
Roger Hyam
Technical Architect
Taxonomic Databases Working Group
-------------------------------------
http://www.tdwg.org
roger at tdwg.org
+44 1578 722782
-------------------------------------
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