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Re: A Question about Agent-based Service Discovery/Selection

From: Francis McCabe <fgm@fla.fujitsu.com>
Date: Fri, 5 Mar 2004 08:55:31 -0800
Message-Id: <E9BE94DF-6EC5-11D8-BC78-000A95DC494A@fla.fujitsu.com>
Cc: public-sws-ig@w3.org
To: Gregory Huczynski <greg@dcs.gla.ac.uk>

Just a quicky response ...
You are partly right.
However, it is not monolithic, and it is also naive to assume that 
there will be *one* airline interface.

The means of interacting with a service *is* part of the semantics of 
that service. So it figures in the discovery process.

A much more interesting and pertinent issue is whether anyone is 
willing to trust such automatic discovery when spending significant 
amounts of money!

Frank McCabe

On Mar 5, 2004, at 3:00 AM, Gregory Huczynski wrote:

> Hi,
> I'm a newcomer to the area of Web Services, and I've recently started 
> investigating the current research into how services are discovered, 
> and a particular one selected that suits the user's (or application's) 
> needs. I'm interested in how these procedures can be done 
> automatically by some agent-like software entity.
> I've read quite a few position-style papers (e.g. Semantic Web 
> Services, McIlraith et al, IEEE Intelligent Systems, 2001), which 
> advocate describing and advertising services using semantic richer 
> descriptions written in DAML+OIL and OWL. The argument is given that 
> these richer descriptions will be more amenable to automated 
> manipulation and reasoning than those currently provided by discovery 
> mechanisms such as UDDI.
> However, from reading these papers, I am slightly confused by a basic 
> issue. Let's consider an example given in McIlraith et al's paper: .. 
> "A user might say, for example, "Find a service that sells airline 
> tickets between San Francisco and Toronto and that accepts payment by 
> Diner's Club credit card"". I assume that with the 
> agent-OWL-description approach, this problem would be solved by an 
> agent reasoning over the semantic markup of the available services, 
> identifying those that meet the user's constraints.
> However, in order for the agent to book a ticket automatically from a 
> service, it must be able to communicate with it: it must know and 
> understand the service's interface (specified, say, in WSDL). So, my 
> question is this - for problems like the example above, before any 
> reasoning can be done to ensure we meet user constraints, is the 
> service search-space first narrowed down to only those services that 
> implement a WSDL (communications) interface understood by the agent?
> For example, in solving the problem above:
> - Assume that a standard BookAirlineTicket WSDL interface has been 
> defined. Lots of airline ticket services export this interface.
> - Assume that the user's agent knows and understands the 
> BookAirlineTicket interface (it could communicate with a 
> BookAirlineTicket service)
> - In solving the problem, the agent first narrows its search to those 
> advertised services that export the BookAirlineTicket interface
> - The agent then reasons over the identified BookAirlineTicket 
> services' descriptions, and identifies those that meet the user's 
> constraints.
> - The agent then offers these matched services to the user, or books 
> the ticket itself.
> Basically, in order for a service to be discovered, selected and used 
> automatically, do we not require an initial search-space constraining 
> step based on the notion of known / previously-defined service 
> function interfaces?
> Apologies for writing such a long email for such a basic question!
> Thanks in advance
> Gregory Huczynski
> Department of Computing Science
> University of Glasgow
Received on Friday, 5 March 2004 11:56:15 UTC

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