W3C home > Mailing lists > Public > public-sws-ig@w3.org > March 2006

RE: Semantics of WSDL vs. semantics of service

From: Shi, Xuan <xshi@GEO.WVU.edu>
Date: Fri, 17 Mar 2006 19:21:25 -0500
Message-ID: <D81F456794C18B4DA3E2ABC47DBBEEF2094FC5@www.geo.wvu.edu>
To: "'Josh@oklieb '" <josh@oklieb.net>, "'public-sws-ig@w3.org '" <public-sws-ig@w3.org>
Cc: "'drew.mcdermott@yale.edu '" <drew.mcdermott@yale.edu>

We are outsiders anyway as Dr. McDermott said. We who get involved with OGC
services have to also consider how our users to understand the meaning of
the services, how to use the services after we developed them, and we
generated lots of standards for the community to share the meaning of the
services. That means, if we follow the standards, we can consume the
services without question.

The insiders of this community, however, concerns more about machine other
than human. They focus on the logic relationship among the varied components
in their systems, other than the meaning or semantics of the services.
That's why my European friend told me there is no other semantics in the
eyes of such people except logics. Unfortunately I am more concerned about
something besides logics inside the services. That's why I am an outsider
for this community. If you have no such interest focusing on the machines,
you are an outsider too.

However, I have to remind such people to consider why we need anti-monopoly
laws in this country and the world. Those giant companies that have monopoly
control in the domain have to adjust their behavior to cope with such law.
Since once someone has the vested interests through monopoly control in one
domain, it is easy for such person or company to cheat the public community
to raise the price for its product or service unreasonably. 

That's the same analogy to SWS community. If anyone who can do something by
an easy and simple way, but this person just tell the customers that he or
she has to use a complex system to do the same thing, how can you judge such
behavior? By simple approach, it may cost $50k while by complex approach, it
may cost more than $500K. 

Besides research and debate, we also need public hearing to tell the general
community how can they do something in an easy, simple and understandable
way without those more and more complex frameworks and systems. In this
case, there is no way to charge $500k for a $50k cloth.

Xuan



-----Original Message-----
From: Josh@oklieb
To: public-sws-ig@w3.org
Cc: drew.mcdermott@yale.edu
Sent: 3/17/06 12:28 PM
Subject: Re: Semantics of WSDL vs. semantics of service

This discussion is also giving me an inclination towards preemptive
deletion of sws-id emails, which is unfortunate. Between the confusion
of terms (as pointed out, using composition for binding) and "descent"
to XML Schema arguments, it can't be said to advance the cause.

It is rather amazing (heartening or disheartening, I'm not sure) to see
arguments rehashed which have been going on in the OGC (Open Geospatial
Consortium) for years. For example, the use of private XML message
schemas versus SOAP formulations, whether URLencoded service invocations
using HTTP GET are still important, equating SOAP/WSDL with RPC and in
turn with the full spectrum of Web service possibilities, the idea that
the useful information abstractions of WSDL should command  slavish
devotion to its syntax (as well as claim to completeness). 

In truth, and disjoint vocabulary aside, we are all fairly well agreed
on the general information which is needed to productively discover,
bind, and consume a remote service over the Web. We should focus on  the
substantive general questions that remain. For instance, is it advisable
to abstract away all knowledge that an operation is being invoked on a
remote service over the Web (probably not)? Should services be
self-describing (probably so)? Is coupled content an important part of
service semantics (yes and yes)? Does WSDL impart all the information
needed (for a machine) to use a remote service outside of a small circle
of friends (no). Is it important to represent in service information how
a service processes inputs to generate outputs (yes, different geocoding
services for example have their own idiosyncratic heuristics
irrespective of the syntax)? Where are syntax standards useful for
interoperability? Should we get all wound up about whether this
additional service information is contained in a WSDL <definitions>
element, referenced from within a WSDL <definitions>, outside of a WSDL
<definitions>  (not really that important a question)?

Cheers,

Josh


Joshua Lieberman, Ph.D.

Principal, Traverse Technologies Inc.

mailto:jlieberman@traversetechnologies.com

tel +1 (617) 395-7766

fax +1 (775) 514-6621


On Mar 16, 2006, at 11:20 PM, Drew McDermott wrote:




[Shi, Xuan]


... I know I said something different from the others. Such as what is
service composition? My definition is different from the so-called
"standard" meaning, but I think it is more realistic and understandable
for
all users who are not programmers and AI professionals to consume Web
services. 


This admission is simply astonishing.  I pointed this discrepancy out
to Xuan months ago in private correspondence.  The SW community
disagrees about many aspects of the "service composition problem," but
everyone agrees it involves computers doing some sort of combination
of solutions of small web-service problems in order to solve bigger
problems.  Because the English word "compose" is ambiguous, and
because Xuan came into this area as an outsider, he originally thought
it meant human composition of web-service requests (as one would
compose an SQL request, for instance).  An honest misunderstanding.

But it is not an acceptable response to such a revelation to continue
to use the semi-standard term in one's nonstandard way.  To do so is
to guarantee that any discussion using the term will be meaningless,
chaotic, and ultimately acrimonious.  (The more so if there are
_other_ terms that are being used in nonstandard ways; who knows?)

I don't see why anyone would pursue this any further.

-- 

                                         -- Drew McDermott
                                            Yale University
                                            Computer Science Department
Received on Saturday, 18 March 2006 00:21:44 UTC

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