Extending SOA Infrastructure for Semantic Interoperability
Extending SOA Infrastructure for Semantic Interoperability Wen Zhu Sumeet Vij firstname.lastname@example.org email@example.com Annual DoD SOA & Semantic Technology SymposiumJuly 14, 2011 www.alionscience.com
SLIDE 2Agenda• Background: SOA and Semantic Technology• Alion Semantic Mediation Bus™• Foundation for a Semantic Enterprise
SLIDE 3Semantics to SolutionsSOAFoundation for Service Interoperability Semantics Mediation Bus™ Runtime infrastructure enables semanticSemantics interoperability through commonCommon Understanding of Business Concepts ontologies, even if the services are implemented using different data models and message standards.Problems• Can Semantics help implement system integration solutions, quickly?• Can Semantics help reduce service development cost?• How I can leverage my investment in SOA infrastructure for Semantic Interoperability?
SLIDE 4 SOA: Benefits and Limitations• Service Oriented Architecture (SOA) • Key Benefits: • Provides standards based mechanism to access Services at the transport and protocol level • Promotes re-use of existing services • Enables fast adaptation to business needs • Aligns information resources to business goals • Limitations: • Current Web Service standards provide the syntactic description of the service interface, but do not describe the meaning or the semantics of the data or behavior. Hence the consumer of the service; whether another service or a human, needs to have intimate knowledge and awareness about the data and its elements • Current Enterprise Service Buses (ESBs) don’t have an out of the box ability to perform Semantic Mediation, that is the transformation and co-relation of data elements and services based on a pre-defined vocabulary • Manual intervention and deep domain knowledge is required to develop custom mappings to correctly use data exposed by these related but different Web Services
Sample Problem: Acquiring Vaccination Info SLIDE 5 from Different DoD HR Systems Vaccinations Lookup Table Data: HEP-B Mission Army HR Field Name: HR Army Vaccinations Reference Plannin Web Army g Service Data: 236R2 SystemArmy Planner 1 Human Communication 3 ARNG HR 1 Specialist ARNG Field Name: Medical Custom HR Web Shots Mappin ARNG g Service Data: HEP-B 2 3 Custom System Integration Marine HR Development Specialist Army 2 Custom Marine HR Field Name:Developer Mappin Web HR HR Army Inoculations g Service Marine Marine Data: Hepatitis-B Shot Excess time is spent interpreting data from different sources despite the usage of advanced IT techniques like Web Services
Semantic Mediation: Dynamically Map SLIDE 6 Information to User Needs Vaccinations Lookup Table Data: HEP-B Semantic Army HR Field Name: Mission HR Army Vaccinations Mediation Web Plannin Army Reference g Bus™ Service Data: 236R2 Army SystemPlanner Semantic Lookup ARNG Field Name: Medical HR Shots Web ARNG Service Data: HEP-B Message Transformation Common DoD HR Ontology Web Service Marine HR Field Name: Endpoint Web HR HR Army Inoculations Service Marine Marine Data: Hepatitis-B ShotAlready under development underBTA’s Leadership
SLIDE 7Semantic Mediation Bus™ Overview• An ontology-based web services mediation bus that enables services with different message formats to interoperate• Implemented as a thin semantic mediation layer on top of a traditional infrastructure Common Ontology Semantic Mediation Bus™ Registry/ Repository Message Schema Web Service Proxy Semantic Lookup and Semantic Mapping Interoperability Annotation Assessment Metadata Management Enterprise Service Bus Protocol Message Message Security Service Adaption Transformation Routing Discovery Traditional SOA Semantic Mediation infrastructure Infrastructure
SLIDE 8Key Characteristics• Cooperation through federation, instead of standardization • The ontology driven approach avoids imposing a standard that has to be agreed by everybody, thus allowing the agencies to select the formats best suited for their business needs, while still being able to use services offered by other agencies.• Increased ability to adapt to the ever changing business needs in a timely and cost effective manner • The semantic mediation approach encourages transformation logic to be declaratively defined in the ontology, instead of buried in the code, often in multiple places.• No need for rigid conformance • Through loose coupling, the SMB allows transformation between message formats which might not be a complete match.• Building on SOA infrastructure, instead of replacing it • By extending ESB infrastructure, organization can leverage their SOA investment and the existing expertise of their personnel.
SLIDE 9Open Standard Compliance• Web Ontology Language (OWL)• Semantic Annotations for WSDL and XML Schema (SAWSDL)• Extensible Stylesheet Language Transformations (XSLT)• Web Service Definition Language (WSDL) Semantics OWL SAWSDL WSMO Services WSDL SOAP REST Data XML XSLT URI
SLIDE 10Semantic Annotations for WSDL and XMLSchema (SAWSDL)• Relate the Service and Message description to the meaning captured in an Ontology. • Annotations can be applied to all WSDL elements and XML Schema types.• Define transformation between wired message format and the ontology representation. XML Schema Enterprise Vocabulary <xsd:ComplexType name=“Vaccination” ont:Vaccination sawsdl:modelReference=“… …” a rdf:Class sawsdl:liftingSchemaMapping=“…” … … sawsdl:loweringSchemaMapping=“…”> XSLT Import SPARQL+XSLT WSDL Service Ontology <operation name=“getVaccinationInfo” sawsdl:modelReference=“… …”> svc:vaccinationInfoRetrival svc:payload ont:Vaccination … … <input message=”…”>
SLIDE 11Extensibility Considerations• Pluggable to SOA Platforms • Integrate with existing Enterprise Service Buses (ESB) • Interact with Service Registry (ebXML, UDDI, proprietary)• Adaptable to Service Design Choices • Mediate SOAP-based Web Services • Support REST and Plain XML Data • Service Metadata• Provide Intelligent Mediation • Assess service compatibilities based on semantics
Technical Architecture SLIDE 12 Traditional SOA infrastructure Service Consumer cannot Semantic process the WSDL as Mediation implemented by the provider Registry/Repository Infrastructure WSDL WSDL Initial implementation uses However, the WSDL SAWSDL lifting and lowering messages can be traced to XML XML rules, which define how XML an ontology understood by Schema Schema messages are transformed to the consumer. and created from an ontology SAWSDL SAWSDL Annotation Annotation Lifting and OWL Lifting and Lowering Rules Ontology Lowering Rules Semantic Mediation Bus Extension Framework XML/WSDL-OWL Semantic Lookup Extension API The engine Mapping dynamically Mediation Engine exposes a web is implemented Message Interoperability as component of service endpoint as Transformation Assessment Algorithm a proxy to the the ESB. service. The endpoint expose a Web Service ESB Adapter WSDL that can be Aggregation Proxy The service accepted by the proxy may consumer aggregate Service service fromService Consumer Provider multiple ESB API Service providers based Service Endpoint on the need of Endpoint consumer. Service Enterprise Service Bus Endpoint
SLIDE 13Building Block for Enterprise Solutions• Enterprise Challenge: Data integration is as much an issue as in the inter-organizational context • Data mash up solution from disparate systems • Incorporation of unanticipated sources in business intelligence • Enhancement of situational awareness through on-demand integration of data• Opportunity: Ontology is not only a tool for understanding, but also a basis for executable solutions
SLIDE 14SMB as Part of a Semantic Enterprise Continuous Business Process Improvement SMB is part of the technology capability that extends traditional SOA to enable semantic service discoverability Shared Understanding and interoperability.Ontologies reflectingShared understanding of Technology Capabilitiesbusiness concepts isdeveloped by engagingthe established Service Oriented InfrastructureCommunities of Interest(COI) and Subject MatterExperts (SME), consistentwith the Department of Secure and effective ITDefense (DoD) Net- infrastructure is theCentric Data Strategy. foundation for Net-Centric information sharing.
SLIDE 15Summary• Put Ontologies to Work • Enhance service understandability at design time • Facilitate service interoperability at runtime• Leverage Existing SOA Investment • Increase service discoverability and interoperability through semantic annotation • Build on existing services • Use in-house expertise• Streamline Service Integration • Shorten development lifecycle by eliminating the need for custom message mapping • Reduce maintenance cost by leveraging existing infrastructure