- From: Battle, Steve <steve.battle@hp.com>
- Date: Mon, 21 Jun 2004 14:03:37 +0100
- To: "Public-Sws-Ig (E-mail)" <public-sws-ig@w3.org>
6/10/04 SWSL telecon Attending: David Martin Michael Kifer Sheila McIlraith Rick Hull Steve Battle David: the June SWSL face-to-face will occur. Notes on SWSL-Profile meeting ----------------------------- Four key topic areas 1) what expressiveness? Pretty much determinied - LP with non-monotonicity, and possibly some bells and whistles (e.g., prioritization of rules). Shiela: any notion of subsumption? MichaelK: some notion of frames to give taxonomic structure, but not subsumtion in DL or OWL sense MichaelK: we decided on an intersection of OWL-S and LP paradigm, emphasizing the LP side. i.e., OWL capabilities that can be expressed within LP Sheila: so the basic language will be undecidable MichaelK: right David: so taxonomic info is important for SWSL-Profile? Sheila: yes - it is natural for people to use - we should make sure that we've got reasonable computational machinery to work with this MichaelK: conceptually this is important, but it doesn't add expressive power unless we get into the non-monotonic reasoning about it ------- 2) Surface Language: this has bubbled to the top as a key issue David: it would be a quick win if we could find a surface language that is appealing and easy to work with Sheila: will the surface syntax be "general-purpose" or "services-targeted" MichaelK: no specific keywords for services. Some vocabulary will come from OWL-S. "service" will probably be a class in this Sheila: that the surface syntax is domain-independent, but we will be able to express a services-specific ontology, which would typically be used Dave: analogous to PSL, which uses FOL as surface syntax and then a domain theory which provides a number of domain-specific predicates, etc. Dave: that there are 2 proposals for surface syntax MichaelK: Benjamin's proposal is LP with priorities (based on his work) a second proposal is F-logic MichaelK: that Michael and Benjamin will work to merge the 2 proposals, next week that this might all be embedded somehow into RuleML RuleML continues to grow, eg, to include F-logic David: is the Forum effort developing an XML-based syntax for serialization? MichaelK: there are several F-logic-based languages What Deiter is using what some company is using what MichaelK is using what Stefan Decker is using we are trying to come up with a unified syntax, and also an embedding into RuleML as the XML-ified version ----- 3) Deciding on the domain theory, the core concepts, in which you say things about services, time relationships, policies agreed to adopt a layering approach, analogous to PSL start with a core, and then various modules you can add on David : one thought is to try to tie with the W3C Arch group ontology MichaelK: what about tieing to the SWSA ontology David: do they have a clean, concise listing at present of an ontology? Rick: we should also coordinate this with the SWSL-Process David: XACML was mentioned, Rosetta net, UBL (an update to ebXML) --------- 4) Show some value/apps to web services world at large ------- Steve: that Katia was making a case for exploiting OWL-S profile Dave: yes, to add rules onto profile, and we'll have a new service language which will let us express things in a more appealing fashion. Notes on SWSL process modelling ------------------------------- MK: In the process modelling subgroup we decided to postpone the issue of the surface language to concentrate on core concepts from PSL. We require something more like a constraint language than a pure process composition language. The work for the next few weeks is to decide what we need from the process model. MK: Reified formulae can be used to represent preconditions and postconditions to bridge between the profile and process models. SM: One problem we had was the issue of the closed world assumption. Are preconditions conjunctive, or do we also allow disjunctions? MK: Do you need to make the closed-world assumption for match-making or for planning? SM: For planning. The compilation step from the process model to the profile has the disadvantage that it results in complex formulae. MK: LP can deal with certain kinds of disjunctions. In the body, yes, but not in the head. DM: The OWL-S profile advertises a single process - we want to advertise a service, which may comprise many processes. DM: Both the profile and process models express IOPEs. The difference between them is in the level of description. SB: I see the difference as static verus dynamic service descriptions. MK: Is redundancy of IOPEs inevitable? SM: A major complaint about OWL-S is this redundancy, the lack of a mapping between IOPEs. Originally the plan was that the IOPEs in the profile would be generated from those in the proicess model. DM: Do we really need IOPEs at all in the profile, or are they described at a different level of granularity? In OWL-S the profile is really only for advertisement, it should address what we really mean by 'service'. SM: Even if IOPEs are only used to select services there should be some relationship between them. MK: How does this relate to choreography? SM: The preconditions and effects of a composition can be derived. For a sequential composition A;B the preconditions are those of A and B (modulo the effects of A). The effects are those of A (modulo the effects of B) and B. MK: And for more than simple sequences? SM: Choices are reflected as conditionals. SM: What is the profile being used for? Some complex contracting scenarios seem to require a full process model. SM: What is now the purpose of the Thursday telecon? What commitment is required to join the subgroups? DM: Anybody is welcome at any time - so long as they don't impede progress. MK: External reviewers play a useful role as well.
Received on Monday, 21 June 2004 09:18:16 UTC