- From: Bijan Parsia <bparsia@isr.umd.edu>
- Date: Thu, 24 Jun 2004 11:49:16 -0400
- To: Dónal Murtagh <domurtag@cs.tcd.ie>
- Cc: public-sws-ig@w3.org
On Jun 24, 2004, at 11:33 AM, Dónal Murtagh wrote: > >>> However, there doesn't appear to be any consensus about how >> bindings >>> should be specified. >> >> There is, in broad detail. At least, we hashed it around a few times, >> even on this list, I believe. There will be something. The basic >> outlines are similar to PDDL. The exact syntax was still in the air >> last I checked. > > Any idea where I can find more details about this? See Drew's reply. It will be in the technical overview. [snip] >> It's the other way round. If there *is* such an input, it binds the >> variable in the precondition. If not, it (IIRC) must have only one >> possible binding and is bound against the world state. >> > > er, what's IIRC? Abbreviation for "If I Recall Correctly". >>> Another matter which wasn't addressed during the recent >> discussion is >>> how a preconditon is tested/executed/evaluated - once the condition >>> itself and its bindings have been correctly specified? >> >> Well, it wasn't asked, either. Some of that will be application >> dependent. It does depend on the specification of a KB (or >> the like) to >> evaluate the preconditions against (even after known bindings are >> made). > > If I recall correctly, you suggested that Pellet's conjunctive ABox > query answering module could be used to evaluate such preconditions. Yes. > Is > this true, and if so, what syntax should they be expressed in if Pellet > were to be used for this purpose? We will support, via the OWL-S API, the standard OWL-S precondition language, which will be "SWRLlike" as mentioned before. We'll have RDQL syntax support as well...so I guess you could use that if you really wanted to. >>> Finally, for the purpose of service composition it is necessary to >>> find processes which are compatible from the point of view of their >>> preconditions and effects. For example, a process which has >> an effect >>> such as: >> [snip] >>> could never be executed immediately before a process which has a >>> precondition such as that shown earlier, assuming #cc is >> bound to the >>> same instance in both cases. The point is that the compatibility of >>> some preconditions and effects can be determined without binding >>> information and it might be useful to distinguish these from >>> preconditons and effects whose compatibility cannot be determined >>> without binding information. >> >> In what way? I mean, with some syntax? I would think you (the system) >> could (would) just analyze it. > > What I'd really like to know is whether there exists a tool which can > determine whether two conditional expressions are compatible. I was thinking that a planner could do this. Of course, it wouldn't do precisely what you were asking for, since it doesn't determine compatibility in the general case of the *expressions*. But for the purposes of finding compatible *processes* for *composition* it seems sufficiently useful. Cheers, Bijan Parsia.
Received on Thursday, 24 June 2004 11:50:00 UTC