Re: [xml-dev] RE: Caution using XML Schema backward- or forward-compatib

["Stephen Green" <stephengreenubl@gmail.com>]

Mmm. But then the combination itself will probably
be a new one again - and won't necessarily achieve take-up.

Plus it looks like we've exhausted the possibilities for
some combination of popular technologies applied to
semantic drift. Surely if an existing one works, even if
unpopular, it is better than devising yet another way
to do the same thing and having to standardise that
almost from scratch.

On 07/01/2008, bryan rasmussen <rasmussen.bryan@gmail.com> wrote:
> The idea of Semantic web services is a recurrent theme that doesn't
> seem to have made any big headway. I think it may be because they are
> based on two technologies that have not achieved a lot of uptake among
> the broad range of developers. Perhaps if one wants a new idea to work
> it should be composed of equal parts broadly accepted technologies and
> new technologies.
>
>
> Cheers,
> Bryan Rasmussen
>
> On Jan 7, 2008 10:17 AM, Stephen Green <stephengreenubl@gmail.com> wrote:
> > Interestingly this already exists. I easily found it with a search on OWL WSDL
> >
> > http://www.daml.org/services/owl-s/1.0/owl-s-wsdl.html
> > http://www.daml.org/services/owl-s/1.0/
> >
> > OWL-S
> >
> >
> >
> > On 04/01/2008, Stephen Green <stephengreenubl@gmail.com> wrote:
> > > I'm thinking of something along either of these lines:
> > > Plan (A):
> > > Just as there are advocates of dual purpose urls for semantic web
> > > - a single url which the server detects as being called by human or
> > > by machine and returns either the human-readable content or the
> > > machine-readable metadata (e.g. RDF/S) accordingly, so I would
> > > envisage a special case, perhaps, for WSDL. There might be an
> > > HTTP header attribute, say, that says 'give me WSDL' and another
> > > which say (perhaps in the same header) 'I can also understand
> > > RDF/S' (or OWL-DS or OWL-Lite, say). The semantically equipped
> > > server might return WSDL (or even SOAP at runtime) along with,
> > > perhaps in the HTTP header (until WSDL/SOAP acquire the right
> > > semantics, say), a pointer to a semantic metadata resource or
> > > somehow the resource itself. That resource might be like this
> > >
> > > RDF/S classes and properties
> > > RDF/S descriptions - perhaps 'graphs' of endpoint + XPath + metadata
> > >                              - perhaps a pointer to or inclusion of Schematron
> > >                                or OWL or genericode (for, say, code values)
> > > With some kind of profile or ontology limiting all this for web service
> > > capabilities (perhaps one for WSDL/design time and another for SOAP
> > > /runtime) similar order of complexity to Dublin Core, say, it should
> > > be (am I wrong?) feasible to have tools detect semantic changes
> > > such as the addition of a new code value so the consuming software
> > > 'knows' to look out for it or throw an error if it can't handle new codes.
> > > Phew! Sorry for long sentences (no time for shorter ones!).
> > >
> > > Plan (B): use BPSS with CPPA - ingredients already there in standards
> > > - just add software.
> > >
> > > In both cases, I don't know enough about it but maybe a semantic
> > > reasoner is needed. So combine knowledgebase and WS software
> > > and some kind of profile and special stuff on servers for HTTP.
> > >
> > > Plan (C): find something like this but doable now, e.g. just using
> > > WSDL + SOAP + XML Schema + Schematron and some codelists
> > > defined in Schematron with a way to interpret new code values (like
> > > UBL proposes) without breaking anything (using XSLT to trim stuff
> > > not understood too).
> > >
> > > Plan (D): extend both WSDL and SOAP to include a url to a particular
> > > type of RDF or OWL or Schematron metadata file
> > > (e.g. with codes/values) which can be updated at any time without
> > > new schema or new url - where updates can be detected by equipped
> > > consumer software if need be and exceptions or appropriate action
> > > taken.
> > >
> > > On 04/01/2008, Fraser Goffin <goffinf@googlemail.com> wrote:
> > > > > - each specifying within the WSDL the meaning of the distance
> > > >
> > > > What mechanism in WSDL are you expecting to be able to define semantics ?
> > > >
> > > > Accepting the idea that it might be possible to define schemata that
> > > > provide sufficient meta-data to ensure that semantics are [less]
> > > > ambiguous (i.e. your idea that the introduction of the 'method'
> > > > attribute') is fair enough, but we also need to consider the case that
> > > > Michael [Kay] outlined, that of 'semantic drift'. An information item
> > > > that starts out with one purpose and over time drifts into other uses,
> > > > and of course that very often we don't create a perfect schema in
> > > > version 1.0 with all future needs catered for :-)
> > > >
> > > > As far as the approach of creating a new URL for what in some cases
> > > > should be considered as minor revision changes (note: I don't include
> > > > a semantic change as one of those), I agree, this seems to be an
> > > > un-necessary overhead. Thats why I prefer to categorize changes as
> > > > breaking and non-breaking where non-breaking should provide at least
> > > > backwards compatibility and ideally forwards as well.
> > > >
> > > > Fraser.
> > > >
> > > > On 04/01/2008, Stephen Green <stephengreenubl@gmail.com> wrote:
> > > > > > Not using a codelist but using a method attribute seems to solve
> > > > > > the problem with no need for new url. That seems to be the key.
> > > > > > Add metadata everywhere in version 1. I still wonder: Is RDF/S
> > > > > > going to be a valid way to do this? Would it work? It does seem
> > > > > > to be becoming the standard way to add metadata for semantics.
> > > > > >
> > > > > P.S.
> > > > >
> > > > > With example
> > > > > <distance>100</distance>
> > > > > what meaning does this have? If it isn't clear what distance is meant
> > > > > then maybe there is a need for *two* new web services:
> > > > > - each specifying within the WSDL the meaning of the distance
> > > > > - one for the first meaning and another for the second
> > > > > - both being a distinct improvement on the first
> > > > > - the original being preserved for consumer compatibility where
> > > > >   an attribute like 'method' might break the WSDL consumers
> > > > > This just isn't likely to happen though because there might be
> > > > > all sorts of similarly vague elements throughout the WSDL, each
> > > > > perhaps needing new versions at some point - and a new url
> > > > > or several new urls for each case just doesn't seem acceptable.
> > > > >
> > > > > Maybe if the attribute was not added in the first place then there
> > > > > is a way to add the metadata it would have contained in another
> > > > > way which doesn't break the WSDL consumers. The missing
> > > > > piece seems to me to be 'tool support'.
> > > > >
> > > > > Maybe if OWL were used to add the metadata (as an afterthought
> > > > > if an attribute like 'method' was missed from version 1) there might
> > > > > be a way for a change in such metadata to trigger a signal in the
> > > > > web service consumer. Perhaps that needs to be added to tools
> > > > > and maybe standardization is needed too. I would love to be on the
> > > > > committee deciding what to call any possible extension of WSDL
> > > > > or combination of WSDL and OWL say - maybe there is a way
> > > > > to call it WSDL-OWL and switch letters to make it WS-LD-OWL,
> > > > > pronounced 'wise-old-owl' :-)
> > > > >
> > > > > I don't know enough about WSDL but when working with ebXML
> > > > > I asked for an attribute 'externalDocumentDefRef' to be added to
> > > > > ebXML BPSS. This, were there the tool support, could perhaps
> > > > > allow a pointer to semantic metadata to be linked to a web service
> > > > > via CPP/A and ebBP definitions. I would think tools would have to
> > > > > detect any changes in the metadata and signal that something has
> > > > > to be looked into as a thrown exception (fatal or otherwise). So
> > > > > with the right ingredients in the web service, it is possible for
> > > > > semantic changes to be automatically picked up by suitable tools.
> > > > >
> > > > > --
> > > > > Stephen Green
> > > > >
> > > > > Partner
> > > > > SystML, http://www.systml.co.uk
> > > > > Tel: +44 (0) 117 9541606
> > > > >
> > > > > http://www.biblegateway.com/passage/?search=matthew+22:37 .. and voice
> > > > >
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> > >
> > >
> > > --
> > > Stephen Green
> > >
> > > Partner
> > > SystML, http://www.systml.co.uk
> > > Tel: +44 (0) 117 9541606
> > >
> > > http://www.biblegateway.com/passage/?search=matthew+22:37 .. and voice
> > >
> >
> >
> > --
> > Stephen D. Green
> >
> >
> > Partner
> > SystML, http://www.systml.co.uk
> > Tel: +44 (0) 117 9541606
> >
> > http://www.biblegateway.com/passage/?search=matthew+22:37 .. and voice
> >
> > _______________________________________________________________________
> >
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-- 
Stephen D. Green

Partner
SystML, http://www.systml.co.uk
Tel: +44 (0) 117 9541606

http://www.biblegateway.com/passage/?search=matthew+22:37 .. and voice