RE: Compositions Types:Static and Dynamic

A good way for discussion is to use living Web services to demonstrate the
ideas about static or dynamic service composition. Here is a typical example
for reference:

Do you want to get a 1 or 2 meter resolution arieal photo of your home
place? You can get the photo by aggregating the following living Web
services:

1. ESRI's address geocoding Web service that helps you to get the latitude
and longitude of your home address. Service URL is:

http://www.arcwebservices.com/services/v2006/AddressFinder.wsdl

2. Microsoft's TerraService can give you arieal photos or satellite images
with resolution from 1 m to 2000 km. Service URL is:

http://terraservice.net/TerraService2.asmx?WSDL

Using .NET as an example, for static invocation, programmers has to "Add Web
Reference" first to get a service stub, write OOP program based on the stub
and invoke the service.

For dynamic invocation, without adding any Web references, programmers has
to create a new wsdlService class that has a function InvokeWebService(url,
namespace, ......) which returns an object as the output.

Given the example of AddressFinder Web service, (I am afraid you cannot
figure out how to invoke this service by just reading this WSDL document,
even though you may wish to add semantic annotations into it), the object
returned from invocation is a GeocodeInfo object, which contains
"candidates" that has an array of GeocodeCandidate. Each GeocodeCandidate
has a point class that has x, y coordinates and information about the
coordinate system. 

When you get x, y values through your dynamic composition and invocation
process, then you can use them in TerraService to retrieve the arieal photos
you want.

If anyone can tell us how to use OWL-S, WSMO, WSDL-S or something else to
implement a dynamic composition and invocation to retrieve arieal photos of
your home address from ArcWeb service and TerraService, then we can see the
great achievement in this field. Otherwise, we have to find some other ways
to do this job.

Best wishes,

Xuan

-----Original Message-----
From: Daniela CLARO
To: public-sws-ig@w3.org
Sent: 4/12/06 4:03 AM
Subject: Compositions Types:Static and Dynamic


Hi all, 
 I want to hear from you about composition types. Actually, I classified
the composition of sws in two categories: static compositions and
dynamic compositions. 
>From static composition I mean the compositions that know iin advance
all services that will belong to the composition, for example, the use
of workflows, that we decide before which services will participate to
the compostion. Do you have other examples from static compositions? 

About dynamic composition, it is the use of dynamic workflow, the use of
planning to compose, the use of graphs. I mean that we don't know in
advance which services will participate to the composition. Moreover, if
I have a service s1 that need another service s2 in order to be
executed, so the dynamic composition should find this other service s2
and put s2 in the composition. Isn't that? Do you have other examples of
dynamic compositions? 

So I want to hear from you what do you think about this classification
and examples of static and dynamic compositions. 

Thanks in advance, 
Daniela CLARO

Received on Friday, 14 April 2006 16:11:17 UTC