Doubt about expressing partial order plan in OWL-S 1.1

If the resulting plan is in partial order manner, I'm wondering 
whether we can directly use the constructs (such as Sequence,
Unordered,Split-join) in OWL-S process model to express the plan. 

For example:
OperationB<OperationEnd,
OperationC<OperationEnd,
OperationD<OperationB,
OperationD<OperationC,
OperationE<OperationC
OperationBegin<OperationD
OperationBegin<OperationE
(Note: OperationBegin, OperationB, ... mean performs of 
the processes)

If "Unordered" construct allows interleaving,
can we express the above plan as following ?
-------------------------------------------------
X1=(Sequence OperationB OperationEnd)
X2=(Sequence OperationC OperationEnd)
...
X7=(Sequence OperationBegin OperationE)
Y=(Unorder X1 X2 X3 X4 X5 X6 X7)
-------------------------------------------------
***I don't know whether the same perform instance can appear
in two or more constructs.***

However, from the previous discussion about "Unordered" construct,
it seems that the construct does not allow interleaving, which is 
a little different with the technical report of OWL-S 1.1. I guess
the reason may be: some processes' performs do not allow concurrency
(Is it because their intermedia states when performing may interfere 
with each other? If it's the case, how can we know that from their 
service descriptions), but they can be performed in any order.

Can you offer some situations when it must use "Unordered", not 
"Split-join" construct?

-- 
Best regards!

Manshan Lin (林满山)
Email: lmshill@hotmail.com;lms-hill@21cn.com;lmshill@gmail.com
Affiliation: School of Computer Science and Engineering, the South
China University of Technology
Phone: (+86)13711287277
2004-12-27
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Received on Monday, 27 December 2004 03:04:11 UTC