Re: Execution of Split

Hi Lihui,

    According to my understanding, the execution sequence in your example is independent of the data flow among AB and CD.  C, D won't get to be executed until A, B have all finished execution in any case. The following illustration ought to be clear enough:
        _ A_
    _ /        \_C_D_
       \_ B_/

    Scenarios using Split can be seen in many papers. For example, a composite service might be designed to booking airline tickets and hotel rooms in target city for travelers(e.g. a researcher to attend a conference in remote cities). If the traveling dates are specified,  the order of two kinds of booking won't make sense. Therefore the two process, BookingAirline() and BookingHotel() are appropriately comosed by "Split".

----- Original Message ----- 
From: "lei lihui" <lei_li_hui_2003@yahoo.com.cn>
To: <public-sws-ig@w3.org>
Sent: Tuesday, May 16, 2006 1:33 PM
Subject: Execution of Split


> 
> Dear all,
> 
> I do not understand the execution of composite services combined with Split .
> Could you give me a scenario that can be implemented with a composite service combined with Split . 
> 
> 
>>From the OWL-S process model (http://www.w3.org/Submission/OWL-S/#5), 
> I know that " the components of a Split process are a bag of process components to be executed concurrently and Split completes as soon as all of its component processes have been scheduled for execution".
> 
> Suppose there is a composite process E which is executed as follows: 
>  Split(A, B), afterwards, Sequence(C,D)
>   
>  Process E
>     <sequence> 
>      <first>
>            <split> 
>                  <process> A </process>
>                  <process> B</process>
>            </split>
>      </fist>
>      <rest> 
>               <sequene>
>                   <process> C </process>
>                   <process> D </process>
>               </sequene>
>      <rest>
>   
>  There are two scenarios may occur:
> 1. A and B do not return any information to E, 
> 2. A and B return some information to E at any time.
> What is the temporal relationship between A, B, C and D? 
>   
>  I think that:
>   
>  If A and B do not return any information to E, then A, B, C, and D are executed in parallel. If A and B return some information to E, suppose the outputs of A is the part of inputs of C and the outputs of B is the part of inputs of D, then  
> A, B, C, and D are executed in parallel with some constraints (A is before C, B is before D, and C is before D)  such that the temporal relationship may be (ABCD), (BACD), and (ACBD). 
>   
>  Please send me comments and discuss with me.Thanks.
>   
>  Best regards.
> 
> Lihui Lei
> 
------------
ZHAO, Wenfeng
PhD. Candidate in CS
Beijing University of Posts and Telecommunications(BUPT )
zhaowenfeng@gmail.com

Received on Wednesday, 17 May 2006 02:51:53 UTC