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RE: service type and the Semantic Web

From: <simon.2.thompson@bt.com>
Date: Wed, 7 May 2003 00:05:14 +0100
Message-ID: <B5E87B043D4C514389141E2661D255EC013680E5@i2km41-ukdy.nat.bt.com>
To: sambrosz@IPIPAN.Waw.PL, public-ws-chor@w3.org

Hi Guys,

	I agree with Stanislaw.

	Clearly the interface of a service doesn't tell us what it does.
For example we can have two services double sqr(double) and double
sqtrt(double) that have the same interface but do radically different
things; of course we can have another service : double arbitary(double)
that does anything at all!

	On the other hand I would say that there is another alternative,
which is to write the interface declaratively; this permits
interpretation on the fly of the semantic of the service interface. 


> -----Original Message-----
> From: Stanislaw Ambroszkiewicz [mailto:sambrosz@IPIPAN.Waw.PL] 
> Sent: Tuesday, May 06, 2003 6:18 PM
> To: public-ws-chor@w3.org
> Cc: Stanislaw Ambroszkiewicz
> Subject: service type and the Semantic Web
>  >> Jon Dart wrote:
> > >> So service type is just a more generic term and a WSDL 
> interface is 
> > >> just part of the definition of that type.
> Consider two services; each of them performs one operation. 
> Suppose that input data types of the two services are the 
> same as well as the output data types. Is it possible that 
> these services perform different operations?
> If the answer is NO, then service type is hard-coded in the 
> input and output data types. It means that the pair of input 
> and output data types determines the type of service. It is a 
> solution to the problem of service type. The solution is of 
> particular interest for procedural (imperative) approach to 
> service composition, like BPEL. Then, the type of composite 
> service as well as the interface can be created automatically 
> from BPEL code. Please note that if the service type 
> (proposed by Sanjiva Weerawarna) had been included in WSDL 
> 1.2, then it would be hard or even impossible to create the 
> interface of composite service automatically. If I am not 
> right, please let me know it.
> If the answer is YES, then it is clear that the service type 
> is necessary, and there must be another means to express the 
> type of service. The solution proposed by Sanjiva Weerawarna 
> seems to be insufficient, i.e., something more is needed than 
> just giving a name to a service type. IMO the concept of 
> service type is related to the more fundamental concept of 
> meaning on the Web. However, it seems that DAML-S did not 
> succeed in achieving its ambitious goal; it was reduced more 
> or less to WSDL + UDDI + BPEL. Perhaps it is the high time to 
> come back to the roots of the Semantic Web.
> Best regards,
> Stanislaw
> ---
> Stanislaw Ambroszkiewicz
> Polish Academy of Sciences          http://www.ipipan.waw.pl/mas/
Received on Tuesday, 6 May 2003 19:05:33 UTC

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