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Difficulty with DAML-S

From: Charlie Abela <abcharl@maltanet.net>
Date: Thu, 10 Jan 2002 17:25:51 -0000
To: <www-ws@w3.org>
Message-ID: <HGEBLIDFMBJHNGBAOLIKAEFECCAA.abcharl@maltanet.net>
Hi All

I am trying to understand some fundamental issues associated with DAML-S and
am hoping that someone out there can help me clarify them.

As regards the IOPEs,
When a requester agent queries a matchmaker then as a result the latter
would return information regarding a matched web service. This information
would include the IOPEs which come from the service Profile and which the
provider would have advertised with the matchmaker earlier. Correct?

As regards a service requester:
So in practice the requester would already know about these IOPEs, what it
doesn't know is the type of process, be it atomic or composite. If it is
atomic then no intermediary steps are needed, and presented with the input
he provider agent should present the output, but if it is composite then
there has to be a continuous "consultation" with the process model to
identify the workflow from the input to the output (with the possibility
that the intermediary output of one atomic service is used as an output to
the next atomic process in the sequence) until all the processes involved
are executed.
Is this correct?

So the process model would be a guide for the requester agent that indicates
to it which inputs it (requester) has to present and which outputs to
pretend from an atomic process (from the provider). So in practice the
requester must avail itself of an interpreter and a parser, so that with one
it parses the process ontology and with the other it understands what to
make out of this parsed structure. Correct?
Any suggestions of already available interpreters to use?
Is it sensible to think of an interpreter as for example a group of java
classes specializing in giving meaning to DAML constructs?

So the parser/interpreter would be able to lead an agent to discover that
the input for a certain service is a string and is referred to for example
“bookName”. But how is the autonomous agent going to “understand” that the
required output is the book’s name and not it’s ISBN? Also such a
description in the requester’s KB would not be described as bookName but as
for example: “bookTitle”. How is this mapping handled? Or is this not in the
scope of the DAML-S ontologies? Is there a solution for this problem? Or is
this a million dollar question?

As regards the service provider:
the work of the provider is to advertise the service profile with a
matchmaker, pass the required inputs into the web service's methods and pass
the computed outputs to the requester. Is it not? Have I left something out?

Regards

Charlie
Received on Thursday, 10 January 2002 12:38:31 GMT

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