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[Fwd: Re: Model of Concurrency in DAML-S -Reposted]

From: Monika Solanki <monika@dmu.ac.uk>
Date: Mon, 22 Sep 2003 07:48:19 +0100
Message-ID: <3F6E9B33.2050804@dmu.ac.uk>
To: www-ws@w3.org

On Friday, September 19, 2003, at 06:59  AM, Monika Solanki wrote:
[snip description and option 1, as I disscuss it elsewhere]

> Option 2:
> Since communication will actually happen within the atomic services of 
> these composite services and since atomic services can execute 
> sequentially or independently in parallel with each other, the 
>  representation of this problem in DAML-S is possible in terms of 
> atomic services and control constructs.
> I am certain abut option 1, however option 2 may solve this problem. I 
> want a second opinion about option 2. Will the actual solution need 
> new constructs or is option 2 the solution

I'm not sure I understand option 2. I don't see how communication 
happens *within* the atomic services. If you mean that we can notice 
the dataflow dependancy and rewrite the parallel construct as a 
sequential one, that seems right to me.

I'd go further and point out that if we have glass box views of the 
communicating process, we might discover that B needs info for A in 
step 47 of (rather than step 1). So, sequencing all of A before all of 
B would be unfortunate. (It still could be handled. I'm not sure, but I 
think SHOP2 would be able to build this compositoin (well, with 
concurrancy awareness added in.) You should get something like a split 
all of A, steps 1-46 of B, join on 47, etc..

I'll note that this seems to be the kind of composition (coordinating 
message exchanges) folks like Richard Hull are talking about.


Monika Solanki
Software Technology Research Laboratory(STRL)
De Montfort University
Hawthorn building, H00.18
The Gateway
Leicester LE1 9BH, UK

phone: +44 (0)116 250 6170 intern: 6170
email: monika@dmu.ac.uk
web: http://www.cse.dmu.ac.uk/~monika
Received on Monday, 22 September 2003 02:44:15 UTC

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