RDF/architecture/ontology - migration

Ricardo Scachetti Pereira ricardo at TDWG.ORG
Mon Nov 21 22:25:57 CET 2005


    You've raised a very important issue. Deciding whether our community
should continue to use XML Schema or adopt RDF, (or anything else for
that matter) is a sizeable discussion. Although it is intrinsically
related to GUIDs, the discussion is well beyond the scope and timeframe
of this group.
    What that tells us is that whatever GUID solution we come up with,
it should leave some flexibility to support either one of the approaches
(i.e., this is a new requirement). So, answering your question (and
Chuck's), it shouldn't matter much. At least not if we are talking about
the underlying GUID infrastructure (the boring part, as some of us say ;)
    To make it more concrete, take LSID for example. It already offers a
hook to solve this kind of problem. Roughly, that's the protocol to
resolve a GUID using LSIDs:

1) Client has a LSID and wants to resolve it. It queries a authority
discovery service (implemented using DNS) to know who can resolve that LSID
2) Client discovers who can resolve that LSID. Client then queries the
resolving authority to find out how to get data or metadata regarding
that LSID.
3) When requesting metadata, the client can specify what kinds of
metadata it wants back. Those types can be any IANA media type (i.e.
HTTP Content-types), such as x-application/rdf+xml,
x-application/xmi+xml, xml, xml-dtd, etc.

    Using that feature one can implement metadata services responding
using XML Schema or RDF independently. So, at least for LSIDs, we have
the hook that will allow GUID group to progress without the need to
answer to your original question. But that will buy us only little time.
At some point, when we turn back to the metadata part of our GUID
solutions and the onthologies (remember, those discussions about what
gets GUIDs for specimens and taxon?). That's when we need to address the
XML Schema vs. RDF question. But at least, we can still separate the
basic GUID framework from the implementation details of the metadata layer.
    Then, depending on how the discussion progresses in other forums
(TAG, probably), we can implemen either one (or both).
    Finally, to address Matt's comments, I'm not suggesting we leave the
resolution loose. I'm just proposing that we leave it open until we get
a clearer map of how to progress.


Roger Hyam wrote:

> This is carrying on from Steve's comments under the "Taxon debate
> synthesis?" thread. I started a new thread as it seemed to be getting a
> little deep and no longer fitting the title.
> Steve's comments are hitting the nail right on the head. From the
> conversations and thoughts I am having about architecture of TDWG
> standards all roads are leading to RDF - which is annoying because it
> makes writing balanced documents that compare the alternatives
> difficult :)
> Steve outlined one of the most promising  paths forward for TDWG
> standards. Taking this route is not a matter of just saying "lets do it
> all in RDF" there would be a long way to go if we went this way - but at
> least we would be doing things the same way the rest of the semantic web
> world and that means there are tools and people out there to help.
> The one point Steve didn't stress is that RDF is the "bees knees" for
> data handshaking - i.e. combining data from different domains. This
> means that the extensibility and version problems that are our main
> hurdles as the moment will tend to go away. But have no fear there will
> be other problems to replace them.
> I am comfortable talking about GUIDs in terms of moving towards
> representing TDWG data in RDF. It certainly makes more sense of the GUID
> discussions to me. But...
> What we need to bear in mind is that there is a great deal of knowledge
> captured in  XML Schema within the TDWG community and that knowledge (or
> at least the good bits of it) need to be migrated forwards. People have
> also invested a great deal of effort in developing XML Schemas and may
> be reluctant to move on.
> This is all leading to TAG stuff rather than GUID stuff but as Steve and
> Rod and others point out the two are very closely connected - along with
> the protocol stuff...
> How much should the GUID debate assume that we are using current XML
> Schema based standards and how much should it assume a move to an RDF
> style approach - or doesn't it matter?
> Roger
> --
> -------------------------------------
> Roger Hyam
> Technical Architect
> Taxonomic Databases Working Group
> -------------------------------------
> http://www.tdwg.org
> roger at tdwg.org
> +44 1578 722782
> -------------------------------------

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