WSMO D3.2: Use Case and Testing Part 2: Syntax and Running Example 2nd F2F meeting SDK cluster working group on Semantic Web Services Lausanne, Switzerland, Holger Lausen Digital Enterprise Research Institute

2 Session Structure WSML –Ontologies –Mediators –Goal as ground fact –Capability: pre and post conditions as restrictions Run time environment –Mapping to flora2 –„Demo“

3 Ontologies Use case shows how to apply the meta constructs outlined in D2 Simple meta model with basic concepts: –Concepts, Relations, Instances, Axioms –More complex patterns like transetivity are for the moment encoded as axioms (e.g. inverse, or transetive) Use case also illustrates –modelling consensus is not easy Ontologies try to be as specific as possible (e.g. avoiding unambiguty by assigning a string as range)

4 Ontologies – Meta Information ontology namespace default= dc= wsml= cnt= ad= xsd= non-functional-properties dc:title "Locations Ontology" dc:date " " dc:type dc:language "en-US" dc:relation dc:rights version "$Revision: 1.4 $" usedMediators

5 Ontologies - Signatures Only well typed ontologies have a model, i.e. everything has to be declared explicitly: –Concepts (including attributes & methods) –Relations –Function Symbols –Variables

6 Ontologies – Concepts / Instances concept time hourOfDay oftype hourOfDay minuteOfHour oftype minuteOfHour secondOfMinute oftype secondOfMinute comment: “A link to large set of instances is missing in WSMO. Therefore, in this version of the ontology we only include some example instances. The inclusion of links to large set of instances will be considered in future versions of WSMO“ instance noon hourOfDay hasValue 12 minuteOfHour hasValue 00 secondOfMinute hasValue 00

7 Ontologies – Function & Relation Declarations function julianDayNumber non-functional-properties dc:description "The Julian Day Count is a uniform count of days from a remote epoch in the past (about 4712 BC). At this instant, the Julian Day Number is 0. Once you have the Julian Day Number of a particular date in history, it is easy to calculate time elapsed between it and any other Julian Day Number" dc:source parameter instant oftype instant range oftype xsd:integer relation contains non-functional-properties dc:description "(interval, intervalOrInstant) is a tuple of the binary relation if and only if interval contains intervalOrInstant and below typing constraints are not violated" parameter interval oftype interval parameter intervalOrInstant oftype (instant or interval) Note: The actual range respectively truth value is defined via axioms.

8 Ontologies – Axioms / Variables Some variable declarations from the data and time ontology: variable X, Y, Z, D1, D2 oftype topConcept variable A, B, C, D, E, F, JDN, JDN_D1, JDN_D2, SFM_T1, SFM_T2 oftype xsd:integer variable T, T1, T2 oftype time variable JulianDayNumber, Difference, SecondsFromMidnight oftype xsd:integer variable Instant, Instant1, Instant2 oftype instant Axioms: axiom intervalContainment logical-expression contains(X, Y) <- X memberOf interval and Y memberOf interval and X.start = Y.end. axiom instantContainment logical-expression contains(X, Y) <- X memberOf interval and Y memberOf instant and X.start = Y.

9 Axioms as integrity constraints Are written in WSML as rules with empty heads axiom depatureBeforeArrival non-functional-properties dc:description "Integrity Constraint: that the departure of a trip has to be before the arrival date" logical-expression <- T memberOf trip[ departure hasvalue D, arrival hasvalue A] and A > D.

10 Ontologies – Use Case Results Revisited The use case as test bed for WSMO –Introduced namespaces Everything is a Literal or a Resource –Introduced XSD data types Literal / value-space mapping and facets (e.g. ordering) –Introduced function symbols –Introduced variable declerations –Introduced anonymous IDs

11 Session Structure WSML –Ontologies –Mediators –Goal as ground fact –Capability: pre and post conditions as restrictions Run time environment –Mapping to flora2 –„Demo“

12 OO-Mediators Mediators that import ontologies and resolve possible representation mismatches between ontologies. In the Use Case: –Converting between different syntaxes (e.g. importing OWL ontology into WSML) –Aligning specifications (e.g. refining or dropping a concept) Declerative description of the latter out of the scope of the use case

13 OO Mediator ooMediator namespace dc= wsml= sourceComponent ontology targetComponent ontology mediationService comment: not yet implemented. mediationService comment: This source ontology might overlap with the owl person ontology. comment: Not yet checked. In case, we should have one mediator importing both comment: and resolving possible overlaps/conflicts.

14 Session Structure WSML –Ontologies –Mediators –Goal as ground fact –Capability: pre and post conditions as restrictions Run time environment –Mapping to flora2 –„Demo“

15 Goal & Capability We achieved discovery by: –Formulating a query out of the restriction given in the pre- and post condition of the service capability –Formulating the goal as a (possible incomplete) ground fact (an instance) Set of facts constrained by the restrictions given in the pre- and post condition of the capability The goal describes one fact, if it is within the restrictions defined by pre- and post condition the service might fulfill the users desire

16 Goal postcondition axiom buyATicketForItinerary logical-expression someItinerary memberOf tc:itinerary[ tc:passenger hasvalue _# memberOf prs:person[ prs:firstName hasvalue "Tim", prs:lastName hasvalue "Berners-Lee", prs: hasvalue ], tc:trip hasvalue _# memberOf tc:trainTrip[ tc:start hasvalue tc:innsbruckHbf, tc:end hasvalue tc:frankfurtHbf, tc:departure hasvalue _# memberOf dt:dateAndTime[ dt:date hasvalue _# memberOf dt:date[ dt:dayOfMonth hasvalue 17, dt:monthOfYear hasvalue 7, dt:year hasvalue 2004 ], dt:time hasvalue _# memberOf dt:time[ dt:hourOfDay hasvalue 18 ] ].

17 Capability – Pre Condition precondition axiom capPrecondition logical-expression InputBuyer memberOf po:buyer[ po:shipTo hasvalue BuyerAddress memberOf loc:address, po:billTo hasvalue BuyerAddress memberOf loc:address, po:purchaseIntention hasvalue X1 and X1 memberOf tc:itinerary[ tc:trip hasvalue X2 and X2 memberOf tc:trainTrip[ tc:start hasvalue X3 and X3 memberOf tc:station[ tc:locatedIn hasvalue StartCountry ], tc:end hasvalue X4 and X4 memberOf tc:station[ tc:locatedIn hasvalue EndCountry ], tc:departure hasvalue X5 and X5 memberOf dt:dateAndTime[dt:date hasvalue DepartureDate ] ] ], po:hasPayment Payment memberOf po:creditCard ] and (StartCountry=tc:austria or StartCountry=tc:germany) and (EndCountry=tc:austria or EndCountry=tc:germany) and DepartureDate > currentDate and ( (currentDate.date.year < Payment.expYear) or ( (currentDate.date.year = Payment.expYear) and ((currentDate.date.monthOfyear <= Payment.expMonth)))

18 Capability Post Condition postcondition axiom capPostcondition non-functional-properties dc:description "the output of the service is an itinerary with a trainTrip for which the start and end locations, and the departure date, are the ones in the precondition. The constraints on the start and end locations, and on the departure date, are, therefore, the ones in the precondition" logical-expression OutputItinerary memberOf tc:itinerary[ tc:trip hasvalue InputBuyer.purchaseIntention.trip ].

19 Session Structure WSML –Ontologies –Mediators –Goal as ground fact –Capability: pre and post conditions as restrictions Run time environment –Mapping to flora2 –„Demo“

20 FLORA-goal mygoal[postcondition-> myTicket:ticket[ itinerary -> _#:itinerary[ startLocation -> innsbruckHbf, endLocation -> frankfurtHbf, departure -> _#:dateAndTime[ date -> _#:date[ dayOfMonth->17, monthOfYear->5, year->2004 ], time.hourOfDay -> 18:hourOfDay ] ], traveller->_#:traveller[name -> 'Dieter Fensel'] ] ].

21 FLORA-capability oebbCap[postcondition] :- X:ticket[ itinerary->Y:itinerary[ startLocation -> StartLoc, endLocation -> EndLoc, departure -> Departure ], (StartLoc..locatedIn=austria ; StartLoc..locatedIn=germany), (EndLoc..locatedIn=austria ; EndLoc..locatedIn=germany), after(Departure, currentDate). Discovery: ?- X:capability[postcondition], X:capability[effect].

22 Further Resources Flora2 implementation: – Latest flora2 encodings: – bin/viewcvs.cgi/wsmo/d3/d32/resources/ bin/viewcvs.cgi/wsmo/d3/d32/resources/

Next: Michael Kiefer „Discovery using transaction logic reasoning“