Re: [OWL-S] Proposal for Making Progress on Process Modeling esp. Preconditons and Effects

> Bijan Parsia <bparsia@isr.umd.edu> wrote:
> 
> On Jan 15, 2004, at 1:05 AM, Michael Kifer wrote:
> 
> >>>>>> "BP" == Message from Bijan Parsia <<bparsia@isr.umd.edu> > writes:
> >
> >     BP> We're especially
> >     BP> interested if people have *problems* with this approach.
> >
> > Situation calculus is not sufficient for process modeling. You need
> > something like Golog. But Golog is *second order*, not first order.
> 
> I'll let Sheila answer this point.
> 
> > I believe that Concurrent Transaction Logic satisfies your needs and  
> > fits
> > the intuition that Mark had (but couldn't express :-). It is also
> > first-order unless you need default negation.
> 
> I'd be interested in a CTL based axiomization of OWL-S. Are you doing  
> one for SWSL?

I am planning to do it this week as part of my SWSL action item.


> What features would SWRL need to support CTL? How easy is it to combine  
> OWL and CTL?

These are two orthogonal things. CTL extends predicate calculus, while OWL
(at least, OWL-DL) is a subset of predicate calculus. Of course, it is
a different issue whether one can make a useful combination out of the two.
In my view, the most important thing(s) about DLs are the subsumption
algorithms. It is not clear how and where you are going to use subsumption
when it comes to process models (i.e., sequencing, parallel composition,
loops, etc.).


> > But I also believe that at some level process modeling requires  
> > defaults
> > as Benjamin argued in
> > http://ebusiness.mit.edu/bgrosof/paps/beyond-mon-inh-wking-pap 
> > -081603.pdf
> 
>  From what I recall, and from a quick re-skim, the argument there was  
> about *relating* process models, or rather, specializing process models  
> in a variety of ways. There isn't a large emphasis on that in OWL-S, at  
> least at the moment, at least, not the way he discusses. The issue  
> we're trying to face is how to effectively present the semantics of an  
> individual process model.
> 
> It's true that a non-mon approach, from what I understand, helps with,  
> e.g., the frame problem, but that can be handled with various other  
> forms of the sitcalc.
> 
> I think Benjamin's example (in figure 1) can be handled in OWL-S, with  
> simpleprocesses, though perhaps not as elegantly.

You can (almost) always avoid defaults for any particular example by
blowing up specifications and incorporating exceptions directly into the
spec. The problem with this is that this is inelegant, makes it hard to
write the specs, and makes the specs non-compositional. New exceptions
must be re-incorporated into the specs, etc. The reason why
object-oriented programming became so successful is because it offers a
way to avoid all this complexity.


	--michael

Received on Thursday, 15 January 2004 12:41:37 UTC