RE: FWD [Work in Progress on Semantics for Web Services (Advance Notice)]

Hello Shi,

In fact you have given a good example whiy more semantics in web services 
is needed with your example. That "reverse engineering" approaches will 
not work out is quite clear. Once you have removed explicit semantics it 
is very difficult to imposible to reconstruct it. I also agree that 
reconstructing frame-based or object-oriented data structures into OWL 
does not help to express semantics. Anyway the help you in creating a 
semantic model for your application - as a first step. This model anyway 
has to be extended by a human user. explaining in more detail what this 
service does. Just from the WSDL it cannot be extracted that the location 
information is the location of the given address. This is also implicit 
information. A semantic information model can help to express this 
meaning.

Reverse engineering anyway is only one side of the medal. The more 
interesting question is how do we design, model, and implement the more 
complex system we will build in the future. Today we use UML to create an 
object-oriented conceptual model of our application. We use an ERP diagram 
to model our data structures. Lateron we implement the system in an object 
oriented language like C#, Java whatever. The initial conceptual model we 
developed in UML however is only implicit later-on in the code. Although 
we have a sound data model we later-on struggle with mapping of relational 
data to object oriented representations. The question now is how to we 
want to develop tomorrow and how semantic technologies can help us 
there.Can we build more self-explainatory application with more explicit 
semantics?


____________________________________________

  Alois Reitbauer
  Multi Agent Systems

  Profactor Produktionsforschungs GmbH
  Im Stadtgut A2
  A-4407 Steyr/Gleink
  Austria

  Tel.       +43 (7252) 885-170
  Fax:      +43 (7252) 885-101
  E-Mail: Alois.Reitbauer@profactor.at
  Web:    www.profactor.at
____________________________________________

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"Shi, Xuan" <xshi@GEO.WVU.edu> 
Sent by: public-sws-ig-request@w3.org
01.09.05 14:55

To
"'Carine Bournez '" <carine@w3.org>, "'Battle, Steven Andrew '" 
<steve.battle@hp.com>
cc
"'public-sws-ig@w3.org '" <public-sws-ig@w3.org>
Subject
RE: FWD [Work in Progress on Semantics for Web Services (Advance Notice)]







Dear Dr. Bournez:

I joined this working group and mailing list but cannot add my comments 
into
the archive. Maybe my opinion is not welcome but I hope more and more 
people
can understand what' wrong for those research approaches on semantic Web
services research when they are used in real world development. I think I
contacted you and many other W3C staffs, directors and writers of OWL-S,
WSMO, WSDL-S. I hope people in this working group will not keep silence on
those known problems.

In my opinion, the mechanism of OWL-S looks like a backward-engineering
process. Since WSDL is the outcome of OOP, then what OWL-S can do is only
restore the object hierarchy and relationship in the development process 
of
OOP. In this way, every object used in the Web services can be associated
with others under such framework but OWL-S cannot describe the meaning of
the objects used in the OOP. 

WSDL-S makes things worse since it only “adds” semantics onto certain
objects while remains the others undefined, that is to say, given the
example of Address Finder Web Service (URL can be accessed at:
http://arcweb.esri.com/services/v2/AddressFinder.wsdl ), WSDL-S would only
add semantics onto such WSDL elements like street, intersection, city,
state_prov, zone, country, user name, password, but ignore the other
elements such LocationInfo, ArrayOfLocation, Location[], description1,
description2, addressFinderOptions, token, matchType, etc. just because 
they
are not meaningful. Thus the whole WSDL file will be a mess for requesters
to understand and use. 

WSMO creates a conceptual model to describe the meaning of the service and
probably can be a useful approach to develop semantic Web services.
Unfortunately, WSMO by now has to “ground” to WSDL to connect both systems
together and to derive the service semantics. If WSDL is NOT the 
appropriate
source from which to derive data and service semantics, WSMO just 
associates
with a wrong object and thus cannot get the correct result. Thus if there 
is
no way to “ground” to WSDL, WSMO is useless as a stand-alone framework.

In conclusion, the source of the problem in their research on semantic Web
services is that researchers just used some simple business transaction
models and then the whole process is simplified. That is to say, all WSDL
elements used in such simple models are intuitive and self-understandable.
However, given the example in Address Finder Web Service, most of WSDL
elements are meaningless, redundant, and irrelevant to the users to set up 
a
direct relation between the input variables and output results. When we 
try
to use such real-life cases to test those mechanisms, then we can find the
true problems. I tried to CMU's WSDL2OWLS tool to convert the WSDL file of
Address Finder Web Service into OWL-S, the result is almost meaningless 
and
users still cannot understand the meaning of the service. Unfortunately,
CMU's Web site for testing their tool is down and maybe they just knew 
OWL-S
approach cannot solve the problem.

What's the semantics for Address Finder Web Service? The direct and 
explicit
meaning of this Web service is: if the user can provide user name, 
password,
and address information on street, city, state (or province), zip/post 
code,
then the service will return the location of the input address.

I suggest that researchers should give up dealing with those simple 
business
transaction models. I know SWS now is a big "business" but please test 
your
approaches and see if your approach can describe the meaning of "Address
Finder Web Service". If it fails, you have to consider what's wrong and
reformat your approach. Don't tell people that your approach can work find
with credit card transaction, buy book, ticket, purchase order, etc. 
etc....
They are just meaningless in the real world.

Any comments and suggestions will be greatly appreciated. I hope W3C and 
SWS
committee members will not keep silence any more to this challenge since
many of them already knew the content of this message for a rather long
time. I look forward to hearing from you.

Best wishes,

Xuan



-----Original Message-----
From: Carine Bournez
To: Battle, Steven Andrew
Cc: public-sws-ig@w3.org
Sent: 9/1/05 6:11 AM
Subject: Re: FWD [Work in Progress on Semantics for Web Services (Advance
Notice)]


On Thu, Sep 01, 2005 at 10:50:47AM +0100, Battle, Steven Andrew wrote:
> 
> Carine,
> Can you shed any light on the decision here to establish a charter for
a
> new working group rather than - or perhaps in addition to - a lighter
> weight incubator activity. The attendee poll at the FSWS workshop
found
> little enthusiasm for such a working group. What caused this shift in
> opinion at the W3C?
> Steve.

Steve, all,

This "Advance Notice" is precisely aiming at gathering feedback about
the
way to go. W3C Members are aware of lightweight process and should react
on member-ws@w3.org about this process.
Thank you for raising this point.

Received on Thursday, 1 September 2005 14:22:50 UTC