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RE: Web Services Architecture Document

From: Ugo Corda <UCorda@SeeBeyond.com>
Date: Fri, 30 Jan 2004 14:27:34 -0800
Message-ID: <EDDE2977F3D216428E903370E3EBDDC9032B8A36@MAIL01.stc.com>
To: "Katia Sycara" <katia@cs.cmu.edu>, "Stephane Fellah" <fellah@pcigeomatics.com>, <www-ws-arch@w3.org>

Katia,
This is a very simple example, but I already have a problem with its
practical usefulness. How would I verify that the service has a URI?
Since we have not defined exactly what a service's URI is (is it the
port address? Is it some document describing the service? etc.), then
the compliance criterion derived from that reasoning does not buy us
much.

I suspect the same problem would surface with most other logical
conclusions we could derive from the WSA ontology. (That's why the
concept of WSA-compliance has a much more fuzzy meaning than the usual
concept of standard compliance - this, by the way, is not the fault of
WSA, it just comes from its special nature of being an architecture
document instead of, for instance, the definition of a specific
vocabulary).

What I am challenging is the practical benefit of using the semantic
machinery in the context of the WSA ontology, not the abstract concept
itself.

Ugo

> -----Original Message-----
> From: Katia Sycara [mailto:katia@cs.cmu.edu] 
> Sent: Friday, January 30, 2004 1:55 PM
> To: Ugo Corda; 'Stephane Fellah'; www-ws-arch@w3.org
> Subject: RE: Web Services Architecture Document
> 
> 
> Ugo, 
>  If you define an X as a Web service then, since a Web 
> service is a service and since a service is a resource, then 
> this X has to have a URI (this is a very simple example, but 
> if this X does not have a URI, then it is not compliant with 
> what the wsa document calls a Web service). 
>   --Katia
>    
> 
> -----Original Message-----
> From: Ugo Corda [mailto:UCorda@SeeBeyond.com] 
> Sent: Friday, January 30, 2004 4:44 PM
> To: Stephane Fellah; Katia Sycara; www-ws-arch@w3.org
> Subject: RE: Web Services Architecture Document
> 
> Stephane,
> I understand the idea of "automating the search of services 
> based on the agent criteria and perform semantic translation 
> of parameters between the services" (the UDDI TC has being 
> discussing exactly this kind of issues recently). I just 
> don't see how all that would relate to the WSA ontology and 
> leverage it.
> 
> Ugo
> 
> > -----Original Message-----
> > From: Stephane Fellah [mailto:fellah@pcigeomatics.com]
> > Sent: Friday, January 30, 2004 1:35 PM
> > To: Ugo Corda; Katia Sycara; www-ws-arch@w3.org
> > Subject: RE: Web Services Architecture Document
> > 
> > 
> > Ugo,
> > 
> > I have been actively involved in different OpenGIS web
> > services testbeds 
> > (http://www.opengis.org/initiatives/?iid=79). The goal is to 
> > enable the integration of different information communities 
> > using geospatial information and services (map, feature, 
> > coverage, processing services...).
> > 
> > One of the most obvious need for a web service ontology is to
> > enable web-agent to perform automatic (read intelligent) web 
> > service discovery and choregraphy of services. 
> > Let's suppose you want to perform a complex task such as 
> > create a 3D map on a specific area. Your 3D Map agent will 
> > need to find the map from some Web Map Server (WMS) and the 
> > DEM from a Web Coverage Service (WCS) and use a Web Terrain 
> > Service (WTS) to create a 3D view from the data retrieved 
> > from the WMS and WCS. 
> > To be able to automate this task, there are two approaches. 
> > The first one is a syntaxic one. You define XML schema to 
> > describe each service and data information. The problem with 
> > this approach ? It does not scale. You have to write code to 
> > parse each schema and make semantic mapping  between the 
> > terms of different XML schema. With the floraison of XML 
> > schema standards that exist out there, you can be sure that 
> > integration of different systems is impossible. 
> > The second approach is a semantic approach , which deal with 
> > heterogeity. You describe the services and data with metadata 
> > using a common metamodel (read RDF/OWL). Using inferencing 
> > and rules and common upper ontologies, you can automate the 
> > search of services based on the agent criteria and perform 
> > semantic translation of parameters between the services. WSDL 
> > is far to be sufficient to be able to automate service 
> > chaining. In my scenario, you need to find geospatial 
> > information within a specific location. The information 
> > generated by the service will need to be provided in 
> > compatible formats for the WTS. 
> > 
> > To enable the semantic web, all the backend services and
> > information needs to be viewed by agent as RDF graphs. Using 
> > semantic protocol, the web becomes a huge semantic bus and 
> > expert system. Instead of relying on specific protocols and 
> > syntax, the agents are communicating using semantic information. 
> > 
> > Best regards
> >  
> > Stephane Fellah
> > Senior Software Engineer
> >  
> > PCI Geomatics
> > 490, Boulevard St Joseph
> > Hull, Quebec
> > Canada J8Y 3Y7
> > Tel: 1 819 770 0022 Ext. 223
> > Fax 1 819 770 0098
> > Visit our web site:  www.pcigeomatics.com
> >  
> > 
> > 
> > -----Original Message-----
> > From: Ugo Corda [mailto:UCorda@SeeBeyond.com]
> > Sent: Friday, January 30, 2004 2:47 PM
> > To: Katia Sycara; Stephane Fellah; www-ws-arch@w3.org
> > Subject: RE: Web Services Architecture Document
> > 
> > 
> > Katia,
> > I am trying to think of examples of how your idea of spec
> > compliance verification could be applied.
> > 
> > Are you saying, for example, that if the WSDL 2.0 spec were
> > to be rewritten using OWL, then I could run a compliance 
> > verifier against the WSA ontology and find out that WSDL 2.0 
> > lacks intermediaries support? This seems rather far fetched to me.
> > 
> > Ugo
> > 
> > > -----Original Message-----
> > > From: Katia Sycara [mailto:katia@cs.cmu.edu]
> > > Sent: Friday, January 30, 2004 11:34 AM
> > > To: Ugo Corda; 'Stephane Fellah'; www-ws-arch@w3.org
> > > Cc: katia@cs.cmu.edu
> > > Subject: RE: Web Services Architecture Document
> > > 
> > > 
> > > Ugo, for one, as Stephen suggests the OWL formalization can
> > be used as
> > > an upper ontology for the work of groups such as the OWL-S
> > coalition
> > > or the Semantic Web Services Language committee (SWSL) 
> and Semantic
> > > Web Services Architecture committee (SWSA). The upper OWL 
> ontology 
> > > could be further specialized by these groups, constraints 
> could be 
> > > added etc. In a long term view, one could imagine that if a 
> > new spec
> > > for example were to be expressed in such an ontology, then 
> > > inferences about compliance of the new spec with the architecture 
> > > could be inferred.  Cheers, Katia
> > > 
> > > -----Original Message-----
> > > From: Ugo Corda [mailto:UCorda@SeeBeyond.com]
> > > Sent: Friday, January 30, 2004 11:34 AM
> > > To: Katia Sycara; Stephane Fellah; www-ws-arch@w3.org
> > > Subject: RE: Web Services Architecture Document
> > > 
> > > What I have not been able to figure out so far is the "then what?"
> > > part. In other words, what is the goal for the OWL 
> formalization of 
> > > WSA (besides being a showcase of semantic technologies)? 
> Is there a 
> > > plan to do anything with that formalization? What kind of results 
> > > would you like to achieve once you apply a reasoning 
> engine to that 
> > > information?
> > > 
> > > Ugo
> > > 
> > > > -----Original Message-----
> > > > From: www-ws-arch-request@w3.org
> > [mailto:www-ws-arch-request@w3.org]
> > 
> > > > On Behalf Of Katia Sycara
> > > > Sent: Friday, January 30, 2004 7:52 AM
> > > > To: 'Stephane Fellah'; www-ws-arch@w3.org
> > > > Cc: katia@cs.cmu.edu
> > > > Subject: RE: Web Services Architecture Document
> > > > 
> > > > 
> > > > 
> > > > Staphane,
> > > >  We are working on an OWL formalization of the concepts and 
> > > > relationships in the Web Services Architecture. It will
> > be published
> > 
> > > > along with the final Working Group product by end of next
> > week.  As
> > > > for OWL-S it is not a Working Group of the W3C, though 
> some of us
> > > > would like it to become one.
> > > >   Cheers, Katia
> > > > 
> > > > -----Original Message-----
> > > > From: www-ws-arch-request@w3.org
> > [mailto:www-ws-arch-request@w3.org]
> > 
> > > > On Behalf Of Stephane Fellah
> > > > Sent: Thursday, January 29, 2004 5:27 PM
> > > > To: www-ws-arch@w3.org
> > > > Subject: Re: Web Services Architecture Document
> > > > 
> > > > 
> > > > Hi,
> > > > 
> > > > I have a couple of questions related to the scope of 
> your working 
> > > > group. Is there any chance to see an OWL formalization of the 
> > > > different concepts and relationships exposed in the WS
> > Architecture
> > > > Document ? What would be the next step for W3C : define 
> again new
> > > > XML schemas (syntaxic
> > > > approach) or using semantic web technologies (OWL). I clearly
> > > > favor the last option because the syntaxic approach is too 
> > > > brittle to scale on the web. The OWL-S effort seems to 
> > > > address the same problem, but uses different terms. Is there 
> > > > any harmonization effort between the working groups ? 
> > > > 
> > > > Thanks in advance.
> > > >  
> > > > Best regards
> > > >  
> > > > Stephane Fellah
> > > > Senior Software Engineer
> > > >  
> > > > PCI Geomatics
> > > > 490, Boulevard St Joseph
> > > > Hull, Quebec
> > > > Canada J8Y 3Y7
> > > > Tel: 1 819 770 0022 Ext. 223
> > > > Fax 1 819 770 0098
> > > > Visit our web site:  www.pcigeomatics.com
> > > >  
> > > > 
> > > > 
> > > > 
> > > 
> > > 
> > 
> 
> 
Received on Friday, 30 January 2004 17:27:56 GMT

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