Scaling API-first – The story of a global engineering organization
Extending SOA Infrastructure for Semantic Interoperability
1. Extending SOA Infrastructure for Semantic
Interoperability
Wen Zhu Sumeet Vij
wzhu@alionscience.com svij@alionscience.com
3rd Annual DoD SOA & Semantic Technology Symposium
July 14, 2011 www.alionscience.com
2. SLIDE 2
Agenda
• Background: SOA and Semantic Technology
• Alion Semantic Mediation Bus™
• Foundation for a Semantic Enterprise
3. SLIDE 3
Semantics to Solutions
SOA
Foundation for Service Interoperability Semantics Mediation
Bus™
Runtime infrastructure enables semantic
Semantics interoperability through common
Common 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?
4. 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
5. 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
System
Army 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
6. 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 System
Planner
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 Shot
Already under development under
BTA’s Leadership
7. SLIDE 7
Semantic 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
8. SLIDE 8
Key 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.
9. SLIDE 9
Open 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
10. SLIDE 10
Semantic Annotations for WSDL and XML
Schema (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=”…”>
11. SLIDE 11
Extensibility 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
12. 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 from
Service Consumer Provider multiple
ESB API
Service providers based
Service Endpoint on the need of
Endpoint consumer.
Service
Enterprise Service Bus Endpoint
13. SLIDE 13
Building 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
14. SLIDE 14
SMB 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 reflecting
Shared understanding of Technology Capabilities
business concepts is
developed by engaging
the established Service Oriented Infrastructure
Communities of Interest
(COI) and Subject Matter
Experts (SME), consistent
with the Department of Secure and effective IT
Defense (DoD) Net- infrastructure is the
Centric Data Strategy. foundation for Net-Centric
information sharing.
15. SLIDE 15
Summary
• 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