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

["bryan rasmussen" <rasmussen.bryan@gmail.com>]

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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