Re: schemaMapping issues breakdown (issue 6)

Rama,

We may not have explicity stated it in the paper, but the inherent
assumption is that schemaMapping is used to store both upcast and
downcast. From a SAWSDL perspective, you could think of two attributes
- schemaMapping.upCast and schemaMapping.downCast or some better way
of achieving this.

I know that having mapping both ways adds more complexity to the
spec., but as you correctly pointed out, ontologies are not a good
place either, so there may be no other option.

Thanks,
Kunal

On 5/30/06, Rama Akkiraju <akkiraju@us.ibm.com> wrote:
>
> Kunal,
>
> In the paper you referenced below, you talk about upcasting and
> downcasting. Upcasting information is stored in the WSDL. Where would
> downcasting information be stored? In the ontology? If so, how can we
> burden an ontology to have pointers to elements in individual WSDLs? there
> could many such WSDLs that may need downcasting. By this, may be you are
> inferring that the concepts in the ontology have to updated to accommodate
> enough information abou the terms used in WSDLs that are being matched. Is
> this right? I am just guessing here. Can you please clarify where the
> downcasting information be stored in your work?
>
> Thank you.
>
> Regards
> Rama Akkiraju
>
>
>
>
>
>              "Kunal Verma"
>              <verma@cs.uga.edu
>              >                                                          To
>              Sent by:                  "Jacek Kopecky"
>              public-ws-semann-         <jacek.kopecky@deri.org>,
>              request@w3.org            public-ws-semann@w3.org
>                                                                         cc
>
>              05/29/2006 01:45                                      Subject
>              PM                        Re: schemaMapping issues breakdown
>                                        (issue 6)
>
>              Please respond to
>              verma@cs.uga.edu
>
>
>
>
>
>
>
> Hi all,
>
> We worked on this issue when we were writing the WSDL-S spec. I agree with
> Jacek's comments (especially option 1c). Comments are inline.
>
>   Hi all,
>
>   here's an attempt to break down what I think are the separate issues in
>
>   clarifying schemaMapping (issue 6 [1]). This email is written with my
>   chair hat off. 8-)
>
>   I assume that schemaMapping attribute points to a document that
>
>
>   specifies a transformation. It seems that there are two orthogonal sets
>
>   of options that we need to consider. Wherever I use RDF below I mean any
>   ontological data language (can be RDF, WSML or any such language of
>
>
>   choice).
>
>   1) The transformation is a) between an XML Schema on one side and an
>
>   ontology on the other side (schema-level mapping) or b) between XML
>   document conforming to the XML Schema on one side and RDF data that uses
>
>
>   some ontology on the other side (data-level, runtime mapping).
>
>
>   I believe option a) above is not useful because the XML Schema in WSDL
>   is given and static, the transformation is as static, so the result is
>
>   also static, and therefore it can be saved somewhere and pointed to
>   using modelReference, as opposed to requiring the processor to take the
>   schema, run the transformation, and arrive at the same result every
>   time.
>
>   herefore I assume 1b for the formulation and discussion of the
>
>
>
>   following aspect:
>
>   2) The transformation goes a) from XML to RDF, b) from RDF to XML, or
>   c) both ways.
>
>   Since I dismissed the option 1a above, schemaMapping cannot be used
>   easily for discovery, instead it could be used when a service is
>
>
>
>   discovered to work with the necessary semantic terms, and then the
>   client that has instances of those terms wants to invoke the service so
>   it has to transform between its semantic data and the XML that the
>
>
>   service requires.
>
>
>   I believe that we need to consider both directions because the service
>   both consumes and produces XML messages, so messages for the service
>   have to be created from semantic data, and messages from the service
>
>
>
>   need to be parsed back into semantic data.
>
>   Depending on whether SAWSDL wants to enable invocation or only discovery
>   (and composition, which uses similar data), we may keep or drop
>   schemaMapping, and if we keep it, we may need to talk about which
>
>
>
>   directions of the mapping it should handle.
>
>   The conclusion is that we have to decide whether we want schema-level
>   mapping and whether we want data-level mapping, then what directions for
>   the mapping(s) we want to handle. (I'd say "no, yes, both".)
>
>
> I totally agree with this and I think that modelReference is sufficient if
> providing a semantic match is the only concern. SchemaMapping becomes
> important only during invocation, when the heterogeneties between the XML
> data and the OWL instances have to be considered. Hence, I think that
> option 1c) makes the most sense.
>
>
> We have been working on the issue of providing mapping both ways. We call
> it upcast (XML to ontological language) and downcast (ontological language
> to XML).  I would like to share this paper that discusses some of the
> heterogeneity that may arise and discusses as scenario that uses upcast and
> downcast.
>
> Meenakshi Nagarajan, Kunal Verma, Amit P. Sheth, John A. Miller, Jonathan
> Lathem, Semantic Interoperability of Web Services - Challenges and
> Experiences, Proceedings of the 4th IEEE Intl. Conference on Web Services,
> Chicago, IL, September 2006 (to appear).
> http://lsdis.cs.uga.edu/library/download/techRep2-15-06.pdf
>
> Thanks,
> Kunal
>
> --
> Kunal Verma,
> LSDIS Lab, Dept. of Computer Science,
> University of Georgia.
> URI: http://lsdis.cs.uga.edu/~kunal
>
>
>


-- 
Kunal Verma,
LSDIS Lab, Dept. of Computer Science,
University of Georgia.
URI: http://lsdis.cs.uga.edu/~kunal

Received on Tuesday, 30 May 2006 19:57:43 UTC