- From: Monika Solanki <monika@dmu.ac.uk>
- Date: Thu, 11 Sep 2003 18:45:18 +0100
- To: www-ws@w3.org
- Message-ID: <3F60B4AE.3050908@dmu.ac.uk>
Sheila McIlraith wrote: >Monika, > >In DAML-S we are able to express conditional effects. These are >the side effects of a web service, as contrasted with its output. >E.g., AcmeBookSeller Web Service: > *output* is purchase receipt > *conditionalEffect* is comprised of a *condition* and an *effect* > the *effect* is that the book is sent to the customer, > I am wondering how would this effect be captured at a lower level of abstraction than an ontology. I understand that conditions can be captured as logical formula ( This is also mentioned in Process.owl). Would the effect be a formula as well ? In that case, the complete definition of a conditional effect would be a conjunction of "condition" and "effect" , which has to be used for the composition. > under the *condition* that the book is in stock. > >Side effects of services are critical to encode for the purposes of >automated WS composition, where such effects must be considered in >composing and executing services. (Something we humans do all the time.) > >As to how this relates to the wschor document you were reading, it would >be helpful to have the citation, but without seeing it, here is a >general answer. > I apologise, I should have mentoined this earlier. Web Services Choreography Requirements 1.0 http://www.w3.org/TR/2003/WD-ws-chor-reqs-20030812/ >In the AI planning literature the term "effect" is often >used synonymously with the term "postcondition". It is used >generically to captures the notion of effects which are either conditional >(i.e., conditional effects) or unconditional. > >I'm guessing that ws-chor's notion of "postcondition" is used in this >context. It is possible that they have done away with the notion of >condition in their "postcondition", because this is simpler, but I would >argue, is not sufficiently expressive to capture the true side effects >of web services. > My understanding was they have just the "condition" as "Post condition" and not the "effect" > > >As for what we need for WS composition, we need both the *effect* >and the *condition*, but the *effect* is the key notion. > >Regards, >Sheila McIlraith > > >On Thu, 11 Sep 2003, Monika Solanki wrote: > > > >>In DAML-S we have Preconditions and Effects(Conditions and Effect). >> >>BPEL4WS does not have the notion of Preconditions and Postconditions( to >>the best of my knowledge). However the ws-chor group have defined >>Precondition and Postcondition for the use cases in their requirement >>document. >> >>I am wondering if the semantics of the "Conditions" for "Effects" as >>defined in DAML-S are different from "Post conditions" in ws-chor doc, >>as what we are really interested in is the condition itself. What >>would be lost (just for the sake of argument) if we were to discard the >>notion of "effect" and retain only the condition part of "Effect" i.e if >>I may call it, "Post condition". I say this because I feel that in some >>way the effect part gets reflected in the output. Maybe "Effect" makes >>it more explicit. I guess even for service composition, what we are >>really interested in apart from input -output is the conditions that are >>captured in Preconditions and Effects. I guess what I am really trying >>to say is can we simplfy the notion of Conditional effects by >>attributing it as "post condition" without compromising anything that is >>not covered in any other property parameter. >> >>Any comments / thoughts well appreciated >> >>Thanks, >> >>Monika >> >>-- >>**>><<**>><<**>><<**>><<**>><<**>><<**>><<** >>Monika Solanki >>Software Technology Research Laboratory(STRL) >>De Montfort University >>Hawthorn building, H00.18 >>The Gateway >>Leicester LE1 9BH, UK >> >>phone: +44 (0)116 250 6170 intern: 6170 >>email: monika@dmu.ac.uk >>web: http://www.cse.dmu.ac.uk/~monika >>**>><<**>><<**>><<**>><<**>><<**>><<**>><<** >> >> >> >> > >============================================================================== > >*** Moving to Dept. Computer Science, University of Toronto *** > >Sheila McIlraith, PhD Phone: 650-723-7932 >Senior Research Scientist Fax: 650-725-5850 >Knowledge Systems Lab >Department of Computer Science >Gates Sciences Building, 2A-248 http://www.ksl.stanford.edu/people/sam >Stanford University E-mail: sam-at-ksl-dot-stanford-dot-edu >Stanford, CA 94305-9020 >
Received on Thursday, 11 September 2003 13:39:11 UTC