Extending SOA Infrastructure for Semantic Interoperability

3rd Annual DoD SOA & Semantic Technology SymposiumJuly 14, 2011

Sumeet Vijsvij@alionscience.com

Wen Zhuwzhu@alionscience.co

m

www.alionscience.com

Agenda

• Background: SOA and Semantic Technology• Alion Semantic Mediation Bus™• Foundation for a Semantic Enterprise

SLIDE 2

Semantics to Solutions SLIDE 3

SOAFoundation for Service Interoperability

SemanticsCommon Understanding of Business Concepts

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?

Semantics Mediation Bus™

Runtime infrastructure enables semantic interoperability through common ontologies, even if the services are implemented using different data models and message standards.

SOA: Benefits and LimitationsSLIDE 4

• 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 from Different DoD HR Systems

SLIDE 5

HR ArmyHR

Army

ArmyWeb

Service

ARNGWeb

Service

HR ArmyHR

Marine

MarineWeb

Service

Army Planner

Field Name:VaccinationsData: 236R2

Vaccinations Lookup TableData: HEP-B

Field Name: Medical ShotsData: HEP-B

Field Name:InoculationsData: Hepatitis-B Shot

HRARNG

HR Marine

Mission

Planning

System

Reference

Excess time is spent interpreting data from different sources despite the usage of advanced IT techniques like Web Services

Army Developer

Marine HR Specialist

ARNG HR Specialist

1

1

Human Communication

Custom

Mapping

Custom

Mapping

2

2

Custom Development

3

3System Integration

Semantic Mediation: Dynamically Map Information to User Needs

SLIDE 6

HR ArmyHR

Army

ArmyWeb

Service

ARNGWeb

Service

HR ArmyHR

Marine

MarineWeb

Service

Army Planner

Semantic Mediation

Bus™

Semantic Lookup

Field Name:VaccinationsData: 236R2

Vaccinations Lookup TableData: HEP-B

Field Name: Medical ShotsData: HEP-B

Field Name:InoculationsData: Hepatitis-B Shot

HRARNG

HR Marine

Already under development under BTA’s Leadership

Common DoD HR Ontology

Message Transformatio

n

Web Service Endpoint

Mission

Planning

System

Reference

SLIDE 7

Enterprise Service Bus

Registry/ Repository

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

Traditional SOA infrastructure

Semantic Mediation

Infrastructure

Semantic Mediation Bus™

Protocol Adaption

Message Transformatio

n

Message Routing

Security Service Discovery

Semantic Lookup and Interoperability

Assessment

Message Schema Mapping

Semantic Annotation

Metadata Management

Web Service Proxy

Common Ontology

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.

SLIDE 8

Data

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)

SLIDE 9

XML URIXSLT

Services

WSDL REST

Semantics

OWL WSMOSAWSDL

SOAP

Service Ontology

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.

SLIDE 10

WSDL

XML Schema

Import

<xsd:ComplexType name=“Vaccination” sawsdl:modelReference=“… …”sawsdl:liftingSchemaMapping=“…”sawsdl:loweringSchemaMapping=“…”>

<operation name=“getVaccinationInfo” sawsdl:modelReference=“… …”>

<input message=”…”>

Enterprise Vocabulary

ont:Vaccination a rdf:Class … …

svc:vaccinationInfoRetrival svc:payload ont:Vaccination … …

SPARQL+XSLT

XSLT

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

SLIDE 11

Enterprise Service Bus

Technical Architecture SLIDE 12

Semantic Mediation Bus

Service EndpointService

Endpoint

Registry/Repository

OWL Ontology

XML Schema

SAWSDL Annotation

Web Service Aggregation

Proxy

Semantic Lookup

XML Schema

WSDL WSDL

SAWSDL Annotation Lifting and

Lowering Rules

Lifting and Lowering

Rules

Service ConsumerService Provider

Service Consumer cannot process the WSDL as implemented by the provider

Mediation Engine is implemented as component of the ESB.

However, the WSDL messages can be traced to an ontology understood by the consumer.

Initial implementation uses SAWSDL lifting and lowering rules, which define how XML messages are transformed to and created from an ontology

The engine dynamically exposes a web service endpoint as a proxy to the service. The endpoint expose a WSDL that can be accepted by the consumer

Extension Framework

XML/WSDL-OWL Mapping

Interoperability Assessment Algorithm

ESB Adapter

ESB API

Exte

nsi

on A

PI

Message Transformation

Service Endpoint

The service proxy may aggregate service from multiple providers based on the need of consumer.

Traditional SOA infrastructure

Semantic Mediation

Infrastructure

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

SLIDE 13SLIDE 13

SMB as Part of a Semantic Enterprise

SLIDE 14

Shared Understanding

Technology Capabilities

Service Oriented Infrastructure

Continuous Business Process Improvement

Ontologies reflecting Shared understanding of business concepts is developed by engaging the established Communities of Interest (COI) and Subject Matter Experts (SME), consistent with the Department of Defense (DoD) Net-Centric Data Strategy.

Secure and effective IT infrastructure is the foundation for Net-Centric information sharing.

SMB is part of the technology capability that extends traditional SOA to enable semantic service discoverability and interoperability.

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

SLIDE 15

SLIDE 16

www.alionscience.com