- From: Jacek Kopecky <jacek.kopecky@deri.org>
- Date: Mon, 05 Jun 2006 17:49:28 +0200
- To: verma@cs.uga.edu
- Cc: Rama Akkiraju <akkiraju@us.ibm.com>, public-ws-semann@w3.org
Hi Kunal, I'd say that information necessary for both upcasting and downcasting (what we call lifting and lowering in WSMO grounding [1]) should be in the same place. There is potentially an m:n mapping between various schemata and various ontologies - data from one ontology can be expressed in various schemata, and the meaning of one schema can be described by various ontologies. Each of these links between a single ontology and a single schema has to describe both directions for data mapping, so we should put everything in a similar place in SA-WSDL. Best regards, Jacek [1] http://www.wsmo.org/TR/d24/d24.2/v0.1/ On Tue, 2006-05-30 at 15:57 -0400, Kunal Verma wrote: > 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 > > > > > > > >
Received on Monday, 5 June 2006 15:49:40 UTC