Re: question: relation between WS-CDL and WSCI

Titi Roman wrote:

>
>>Fair question Titi.
>>
>>Okay where do I start....
>>First of all WSCI was an executable language.
>>    
>>
>
>I am a little bit confused here...In the WSCI 1.0
>(http://www.w3.org/TR/wsci/) in section 1.6.2 it says that WSCI "is
>declarative and cannot, by itself, be executed." (I also haven't heared
>about amy execution environments for WSCI). I understood that WSCI possess
>an operational semantics, did you refer to this when you said that WSCI was
>an executable language?
>  
>
WSCI was definitely not intended to be executable, but describe the 
observable message exchange between the participants. It did focus on a 
level of abstraction that some other proposals would consider 
"operational", but any language can be viewed as operational compared to 
a more abstract language.

>>Secondly WSCI has no formal basis at all.
>>    
>>
>
>I have recently read a paper (A. Brogi, C. Canal, E. Pimentel, A.
>Vallecillo: "Formalizing Web Services Choreographies.",  First International
>Workshop on Web Services and Formal Methods (WS-FM 2004), Pisa February
>23-24, 2004.) in which the authors propose a logical formalism based on
>process algebra as a formal basis for WSCI (mainly for reasoning about the
>compatibility of the WSCI descriptions of 2 or more web services).
>  
>
The model for describing the behavior of any one participant/process and 
the composition of that behavior into larger processes is based on 
mobile process calculus.

>Why do you need a formalism in the choreography context (where can be seen
>the usefulness of using such a fomalism for a choreography language)? Where
>is it actually needed?
>  
>
Formalism allows you to make a lot of proofs about the language itself, 
but more interesting, about the specifications you produce using that 
language. In the case of WSCI, formalism becomes more important as a way 
to derive conclusions about compositions, and it allows you to leverage 
the extensive work done in the field of process calculus.

Assaf

>Which is the reason for choosing pi-calculus and not other formalism (e.g.
>Abstract States Machines)?
>  
>
>Where can be seen the usefulness of using pi-calculus as an underlying
>fromalizm for WS-CDL?
>
>
>Thanks a lot!
>Regards,
>Titi Roman
>
>
>
>
>  
>


-- 
"Those who can, do; those who can't, make screenshots"

----------------------------------------------------------------------
Assaf Arkin                                          arkin@intalio.com
Intalio Inc.                                           www.intalio.com
The Business Process Management Company                 (650) 577 4700


This message is intended only for the use of the Addressee and
may contain information that is PRIVILEGED and CONFIDENTIAL.
If you are not the intended recipient, dissemination of this
communication is prohibited. If you have received this communication
in error, please erase all copies of the message and its attachments
and notify us immediately.