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Re: What's the point in using OWL-S?

From: Xuan Shi <Xuan.Shi@mail.wvu.edu>
Date: Sat, 03 Jun 2006 00:28:46 -0400
Message-Id: <s480d7d6.081@WVUGW01.wvu.edu>
To: <gerhard.austaller@o2online.de>, <public-sws-ig@w3.org>

The OWL-S, as well as WSMO, not only provides the description of a
service, but also stresses and focuses more on the process of service
aggregation (or mediation in case for WSMO). Here we see the problem.
Service providers only have the responsibility to provide a semantic
description about the service. How service requesters use the service is
beyond the control of service providers. When service requesters, or
application developers, utilize multiple services to accomplish a series
of tasks, they have to deal with service aggregation or mediation
processes.

For this reason, OWL-S and WSMO mislead the group by blurring the focus
of SWS research, i.e. to describe the semantics of services (service
providers' responsibility), other than to describe the semantics of
service integration (service requesters' responsibility). 

WSDL-S adds semantic annotation into WSDL. In any W3C document, WSDL is
defined as a document of service interface. Thus the semantics of
service interface is not the same as the semantics of service, because
the same service can have different interfaces (see living examples at:
http://lists.w3.org/Archives/Public/public-ws-semann/2006Apr/0029.html)

As for your question, "do we assume that all airlines agree on one
ontology and further also on the process how to do something?" When I
discussed with Jacek off-the-list, he said that service providers have
absolute right to define their own service interface, definition,
ontology, semantics, etc. and, service providers do not need to care
about how requesters will use the service (I stressed on a
requester-oriented approach). Thus you see, there is NO agreement on the
ontology or semantic definition, and that's why people have to use the
logic-based SW technique to guess the meaning of the service
ontology/semantics for matchmaking. Without agreement and
standardization, we can see the problems as I discussed in
http://lists.w3.org/Archives/Public/public-sws-ig/2006Apr/0048.html

At its best, what a programmer can gain from an owl-s description may be
a service composition document which is supposed to tell you how to
chain varied services together for certain tasks/goals. But the
remaining question is how can you invoke the services according to such
a composition result as I discussed in
http://lists.w3.org/Archives/Public/public-sws-ig/2006Apr/0045.html 

I hope you can get more responses from others in this group soon in the
following days.

Best wishes,

Xuan

>>> "Gerhard Austaller" <gerhard.austaller@o2online.de> 06/02/06 12:30
AM >>>

Hi

I still have not understood what exactly an agent can achieve with the
owl-s
description of a service.

Let's take the Bravo Air example. For an agent to book a ticket it has
to
"understand" the concepts used there. But where's the big advantage in
having an interface (in WSDL) defined or an annotated WSDL like WSDL-S?
I
admit having the exact order of steps defined to achieve something is a
step
in the right direction...

Now I want my agent also to book a ticket at another airline. So if this
airline uses another ontology that ontology also as to be understandable
to
the agent made by an programmer. So do we assume that all airlines agree
on
one ontology and further also on the process how to do something?

Do I miss something? Can please somebody explain or give me pointers
what's
a programmer can gain from an owl-s description?

Thanks
Gerhard
Received on Saturday, 3 June 2006 15:00:15 UTC

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