[tdwg-content] DSW questions

Steve Baskauf steve.baskauf at vanderbilt.edu
Fri Jan 27 04:49:33 CET 2012

Cam summarized the situation with DSW 
(http://code.google.com/p/darwin-sw/) pretty accurately.  Additional 

It has been suggested that the way forward on Darwin Core is not to try 
to rewrite the standard to do everything that everyone wants, but to 
build on it in a layered fashion.  The first layer might be to simply 
define terms for the purpose of standardization.  The second layer might 
be to nail down the relationships among the class and property terms of 
the first layer and to establish how they could be represented in RDF to 
allow for data transmission.  A third layer (based on the framework laid 
out in the second layer) might be to describe more complex semantics 
that could be used for reasoning.  As I've described this, the first 
layer is already in place in the form of the current standard.  DSW is 
an attempt to create a second layer.  Although we didn't put much in the 
way of complex semantics into DSW, we hoped that we did not do anything 
that would prevent someone from using it as the basis for a third layer. 

Again, recapitulating what others have said previously, there wouldn't 
necessarily have to be single "upper" layers on this cake that I 
described.  Particularly on layer three, people might create different 
ontologies to accomplish different things.  But minimizing the number of 
second layers to the smallest possible number would be desirable if the 
goal is data interchange.  That's one reason why I took great pains to 
try to document what I thought I was hearing as far as community 
consensus was concerned.  You can look at the various wiki pages to 
judge for your self the extent to which I was successful.  There were 
certain decisions that Cam and I made (such as creating those object 
properties to connect the DwC classes rather than trying to make use of 
the various existing DwC ID terms, and assigning ranges and domains to 
some of the terms) which may or may not have been good ideas.  As Cam 
said, we were hoping for discussion and constructive criticism on our 
approach, which we would still welcome. 

Bob was correct in his post that I (but perhaps not Cam) have pretty 
much reached my limits as far as my ability to add meaningfully to what 
we've put into DSW (and Bob was also basically correct in his outline of 
design criteria).  DSW does for me what I need - provides a way to 
structure RDF describing my images.  At this point I'm trying to focus 
my efforts on the work of the TDWG RDF/OWL task group, in particular 
coming up with a beginner's guide to RDF and to try to compile a list of 
issues that have been raised in the past to complement whatever Joel has 
gotten from his survey.  So I probably won't be putting much further 
effort into DSW development.


Cam Webb wrote:
> Dear Hilmar,
> Thanks for your questions about DSW.  Steve will have more to add, but the 
> simple answer is that DSW was not indented to say anything new about the 
> existing DwC classes themselves, other than offering a suggestion, based 
> on Steve's extensive search for community consensus on usage in the 
> tdwg-content list, of how the classes best relate to one another.  These 
> relations are indicated by the coining of a set of predicates that offer 
> more semantic content than the generic dwc:relatedResourceID, and permit 
> more succinct SPARQL searches, as Bob pointed out.
> Based on Steve's review, the range of ways of using the dwc:Occurrence 
> class has been wide, and we suggested a restricted usage in this ontology: 
> the documented presence of an individual organism at a particular event (= 
> space x time); a specimen/photo/observation is in this case not the 
> occurrence itself, but provides evidence for the occurrence.
> This all depends on the one new class in DSW, the IndividualOrganism, 
> which Steve and others have been proposing as a fundamental class for 
> modeling biodiversity data.  With an IndividualOrganism class, we can 
> easily link from the knowledge domain of biological specimens to that of 
> population biology, where observed/remeasured individuals are the core 
> unit.
> We developed DSW to serve our pragmatic need for a semantic template with 
> which to serve data as RDF. Reasoning with it is possible, as you and Bob 
> noted, but I agree, the range of discoveries is limited, because of the 
> few logical restrictions currently in DSW. Perhaps we should not have used 
> the word `ontology' to describe it?
> As is still the case now as when Steve announced DSW to tdwg-content, we 
> consider DSW primarily a suggestion for further discussion, and hopefully 
> for further community development (i.e. via the nascent TDWG RDF/OWL Task 
> Group).  It `makes sense' to us, and we're using it to model data, but 
> would appreciate significant comment and criticism, including the need to 
> add more logical restrictions.
> Best,
> Cam
> [ There's more on our rationale behind DSW at:
>    http://code.google.com/p/darwin-sw/wiki/Rationale ]
> On Wed, 25 Jan 2012, Hilmar Lapp wrote:
>> Hi Steve and Cam,
>> I have a question re: your design of the current Semantic Darwin Core 
>> ontology. (And this is assuming that with the published 0.2 version I 
>> have the latest one in hand.)
>> My understanding is that all classes in DSW are imported from either DwC 
>> or DC (or FOAF), in order to reuse those terms. While that's a good idea 
>> in principle, it seems that DSW is actually not saying much new (in a 
>> semantic sense) about them, except to declare them to be OWL classes, 
>> and to assert them as disjoint from each other (or equivalent in one 
>> case). DSW then adds a variety of object (and some data) properties, 
>> which distinguish themselves from those in DwC by declaring domain and 
>> range axioms for them. But that doesn't say anything about the classes 
>> either, nor does it, I would argue, about the properties - domain and 
>> range constraint really only say something about the instances for which 
>> one asserts those properties.
>> So by itself the DSW won't allow me to infer anything about the classes 
>> and properties in the ontology (aside from disjointness), though it will 
>> allow me to make more inferences about instance data to which it is 
>> applied than DwC would. And those additional inferences would consist 
>> only of the instances' class memberships (and their non-memberships).
>> I'm wondering a) whether I'm missing something here and am in error, and 
>> if not, b) whether the above was indeed the extent of what you wanted to 
>> achieve with DSW. Either way, what are your current plans with the 
>> ontology? It doesn't seem to have changed for a while.
>> (And please forgive me if this isn't the right list to post to - I 
>> couldn't find a DSW-specific one on the Google code homepage.)
>> Cheers,
>> 	-hilmar
>> -- 
>> ===========================================================
>> : Hilmar Lapp  -:- Durham, NC -:- informatics.nescent.org :
>> ===========================================================
> .

Steven J. Baskauf, Ph.D., Senior Lecturer
Vanderbilt University Dept. of Biological Sciences

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