Re: Effects in OWL-S

On Apr 28, 2004, at 8:45 AM, Austin Tate wrote:

> At 07:41 28/04/2004 -0400, Bijan Parsia wrote:
>> But it should be easy enough to add another field to our condition 
>> object that indicates timepoint of evaluation/application. Would this 
>> be worth anything to you?
>
> It would indeed.  It would reflect the fact than a service invocation 
> (or any activity in fact) has a tie interval over which it takes place 
> and therefore has an (implicit) begin and end time point associated 
> with it... so both can be referred to in constraints.  Note begin/end 
> as the naming for these time points (as in NIST PSL, etc) not 
> start/end or begin/finish - which I think of as poorly paired named.

Sounds reasonable.

>> We could make the current PEs derived subclasses of the more general 
>> case pretty easily. Rename Effects to PostEffects and it even scans. 
>> I don't think calling out this common case is necessarily so bad.
>
> I agree... and you have got it Bijan... the trick is to give the 
> simple (pre)condition and (post)effect as just one case of the more 
> general model.  but the general model would be what underlies the 
> standard... the others would be simple shorthand or syntactic sugar.  
> this gives a much more minimalist and simultaneously more powerful 
> core model.
>
>> Note that this doesn't have to be rolled into our release. It should 
>> be possible to do smoothly in any case. We should try it, Austin. I'd 
>> like to see what you've already done to accomodate your needs.
>
> We would have to introduce dummy or "no op" activities/services and 
> such tricks.

Really? I don't think so. At least, I was hoping not. Remember that 
OWL-S doesn't really have a fixed syntax...its syntax is enocoded in an 
ontology. So you should be able to define a subclass of conditoin, and 
a superclass of effects pretty easily. Why hack it when you can express 
it (in the canonical hacky way :)).

> Jeff Dalton here is just looking at OWL-S export (of the resulting 
> composite service description) from our web services composition 
> demonstration using O-Plan and the new I-Plan.  I will ask him to 
> provide his solution when it settles down.

Well, I would advise consulting before hand. I don't see a need 
WHATSOEVER for dummy services and the like.

Cheers,
Bijan Parsia.

Received on Wednesday, 28 April 2004 09:24:20 UTC