Ontology-derived Activity Components for Composing Travel Web Services Matthias Flügge Diana Tourtchaninova

© Fraunhofer Institute FOKUS, Berlin, Overview  The SATINE Project at a Glance  Service Composition in SATINE  Activity Components  Ontologies for Component Generation  Activity Component Architecture  Benefits  Related and Future Work

© Fraunhofer Institute FOKUS, Berlin, The SATINE Project at a Glance  EU 6th Framework Programme – Specific Targeted Research Project  „Semantic-based Interoperability Infrastructure for Integrating Web Service Platforms to Peer-to-Peer Networks“  Partners  Middle East Technical University, Turkey  Fraunhofer Institute FOKUS, Germany  European Dynamics, Greece  Oxymel, France  Intro Solutions, Turkey  Royal Melbourne Institute of Technology, Australia  January 2004 – June 2006 

© Fraunhofer Institute FOKUS, Berlin, SATINE – Project Goals Overall  Develop a semantic-based interoperability framework for the tourism industry Technical  Provide tools and mechanisms for… …publishing, discovering, composing and invoking… Web services through their semantics in peer-to-peer networks Business  Provide alternatives in the centralized travel business – Currently most bookings go through proprietary and expensive “global distribution systems” (GDS)

© Fraunhofer Institute FOKUS, Berlin, SATINE Architecture and Tools  Semantic Wrapper for Existing Information Resources  OTA-compliant Travel Ontologies (Functionality and Domain Ontologies)  P2P Network Deploying Semantic Routing Mechanisms  Semantically Enriched Web Service Registries  Semantic Query Formulation Tool  Service Composition Framework Travel Ontologies (OWL) Travel Ontologies (OWL) SATINE P2P (JXTA) Service Description (OWL-S) Service Description (OWL-S) Service Query (OWL-QL) Registry (ebXML) Registry (ebXML)

© Fraunhofer Institute FOKUS, Berlin, Service Composition in SATINE - Requirements  Compose complex Web services from simple ones  Provide an easy-to-use visual composition environment  Support a business architect‘s rather than a software architect‘s view  Allow for composition on a semantic rather than on a technical level  Reflect characteristics of the travel business  High competition / wide variety  dynamic selection of partners / services  Fixed business relationships  static selection of partners / services  Use stable and industrial suitable workflow engine  Exploit semantic discovery facilities of the SATINE P2P network  Publish and advertise complex services to SATINE network  Support semantic annotation of composed services

© Fraunhofer Institute FOKUS, Berlin, Service Composition in SATINE – Basic Approach  Abstract functional building blocks with (semantically) predefined goals  Compose complex travel business process from building blocks  Configure (fine-tune) semantics  At execution time each building block is responsible for finding and invoking a concrete Web service (agent-like behaviour)  The semantic description of the service matches with the goal of the building block  Building blocks are self-contained and self-describing  semantic activity components Semantics Visual Composition Tool Semantics (Fine-tuned) Configuration & Deployment Tool WS Semantics Match Lookup and Invoke

© Fraunhofer Institute FOKUS, Berlin, Ontologies for Activity Component Generation  Functionality ontology defines a hierarchy of service classes  Each service class is described by an abstract OWL-S service profile  Concepts (of parameters, properties) are defined in specific domain ontologies … … Service Profile TravelService HotelService VehicleService FlightService InsuranceService FlightAvailabilityService FlightBookingService FlightDetailsService … … Functionality Ontology … … Travel Finance Domain Ontologies  For each class in the functionality ontology an activity component may be generated  The goal of the component is defined by  its position in the functional hierarchy  its OWL-S service profile  Global vs. local ontologies (mappings)

© Fraunhofer Institute FOKUS, Berlin, Activity Component Architecture  Activity component is a collection of pre-packaged classes and corresponding files that offer a set of well- defined interfaces  Presentation interface is used by the composition tool in order to display the activity component to the user  Logo, colours, shape…  Through the introspection interface the composition tool receives ontology concepts of input/output parameters  allows for modelling of data flow on a semantic level  tool analyses semantic correspondence of inputs and outputs, makes proposals to user  BPEL4WS is used as representation format for process execution flows Presentation Composition Tool Introspection

© Fraunhofer Institute FOKUS, Berlin, Activity Component Architecture (cont‘d.)  The configuration interface allows for restricting the range of candidate Web services for an activity component.  Set properties (e.g. location, QoS)  Dynamic service selection (late binding) vs. static service selection (early binding)  In case of static service selection:  Matching Web service(s) has to be determined at deployment time  Activity component exposes its search capabilities through the lookup interface Configuration Configuration and Deployment Tool Lookup

© Fraunhofer Institute FOKUS, Berlin, Activity Component Architecture (cont‘d.)  Workflow engine uses invocation interface of activity component  Process has been defined in BPEL4WS -> workflow engine considers activity component as a plain Web service  Invocation interface is described by an appropriate WSDL file  WSDL has been automatically generated during component creation Invocation BPEL Workflow Engine

© Fraunhofer Institute FOKUS, Berlin, Activity Component Architecture (cont‘d.)  Activity component creates an OWL-QL query asking for matching services regarding  Service class  Concepts of inputs/outputs  Property values  Query is issued at the query interface of the SATINE P2P network  OWL-S profiles of matching services are returned and ranked according to a weighing function  Best matching service is being invoked, results are passed back to the workflow engine Invocation BPEL Workflow Engine SATINE Query Interface SATINE P2P Network

© Fraunhofer Institute FOKUS, Berlin, Benefits  Component-based approach (encapsulation of semantic information, configurable properties and executable code)  Simplified exchange of data between different tools, data consistency ensured  Modify/configure activities without redeploying the process  Composition of business processes on a semantic rather than on a technical level  Orchestration of building blocks with well-defined meaning  Intelligent tool support during composition  Dynamic lookup and invocation  Incorporation of new / better matching services without reengineering efforts  Higher reliability  Transferability to other application domains

© Fraunhofer Institute FOKUS, Berlin, Related and Future Work  Concepts presented successfully apply and adapt existing composition approaches  METEOR-S Project (University of Georgia)  Configurable semantic process and activity templates  Generic Web service proxies for dynamic service invocation  MINDSWAP Project (University of Maryland)  Composition tool presents available service choices based on matching of parameter concepts  Future activities  Implementation of the concepts presented  OWL-S based process definition an execution

© Fraunhofer Institute FOKUS, Berlin, Thank you!