Overview of Semantic Tools Semantic Technology Boot Camp Day 3

2 Overview ▼ Categories of Semantic Tools ▼ Category Overview  Purpose & Role in Architecture  Example Tools  Tradeoffs and Evaluation Criteria

3 Categories of Semantic Tools ▼ RDF Parsers ▼ Triplestores ▼ Ontology Editors & Workbenches ▼ SPARQL Query Engines ▼ Reasoners ▼ Middleware & Servers ▼ Ontology Documentation Tools ▼ Web Development Kits ▼ Specialty Libraries

4 RDF Parsers Like an XML parser, an RDF parser is a software library that will interpret an RDF dataset (or ontology) and construct a memory model of the graph described. ▼ Open Source: Jena, OWLAPI, Raptor.

5 Triplestores A triplestore (also “triple store”) is a type of database optimized for the storage and retrieval of RDF data. ▼ Commercial stores: Allegrograph, Stardog ▼ Open Source stores: Virtuoso, Sesame, Mulgara

6 Ontology Editors & Workbenches An ontology editor offers a visual interface for the composition of OWL ontologies. Many editors go further and offer facilities for ontology publishing, batch operations and script processing over a set of ontologies. ▼ Commercial: TopBraid Composer ▼ Open Source: Protégé, NeOn Toolkit

7 SPARQL Query Engines A SPARQL query engine will evaluate a SPARQL expression over a specified graph and return an appropriate response for the expression type (ASK, CONSTRUCT, DELETE, SELECT, etc.). ▼ OpenSource: ARQ

8 Reasoners A semantic reasoner (aka “rules engine”) will apply inherent and specified rules to infer new facts (as triples) from a given set of asserted triples. ▼ OpenSource: OWLIM, Pellet ▼ Commercial: RacerPro, OntoBroker

9 Ontology Documentation Tools Ontology documentation tools will parse an ontology file and produce formatted documentation generally in HTML or PDF form. ▼ Open Source: Neologism ▼ Commercial: UISPIN

10 Web Development Kits Web development kits for RDF datasets and ontology provide dynamic interfaces to a triplestore to facilitate search and exploration of RDF content. ▼ Open Source: Open Semantic Framework

Leveraging existing (non-RDF) data Day 3 - Basics

12 Overview ▼ Mapping relational data to RDF using D2RQ ▼ Mapping Excel Documents to RDF ▼ Mapping XML to RDF/OWL ▼ Other Mappings (JSON, UML, Java/EMF Objects)

13 Mapping relational data to RDF using D2RQ ▼ Problem Description ▼ Custom Importers ▼ The D2RQ Approach ▼ Related Mappers ▼ Mapping SPARQL to SQL

14 Mapping Excel Documents to RDF ▼ Similar to the RDBMS conversion problem. ▼ Spreadsheets lend themselves to complex tabular structures. ▼ Schema and data can appear anywhere. ▼ One sheet may have any number of independent tables. ▼ Meaning given to style. I.E. bold, italic, font color or cell color may encode meaning. ▼ Multiple cells and formulas.

15 Mapping XML to RDF/OWL ▼ The XML Data Model ▼ Mapping Between Data Models  Finding Meaning between XML Nodes ▼ Custom Conversion ▼ Tools and Toolkits

16 Mapping XML to RDF/OWL Differences in XML The XML model is a tree structure. XML provides structure to a document. The XML utility is data packaging for transmission as messages. Uses schema for conformance validation. Provides a standard that allows parsers to interpret any XML document.

17 Other Mappings ▼ Converting JSON ▼ Importing UML ▼ Importing EMF Objects

18 Sample Applications

19 Design time applications

20 ▼ Completed Work on  Weather  Integrated Surveillance ▼ Started Work on  Unmanned Aircraft System  Flight and Flow ▼ Key Deliverables  COI Ontology  Business Context (DoDAF Artifacts)  Other Artifacts ▼ Consistent with DoD Net-Centric Data Strategy Process for Inter-Agency Shared Understanding Service Description (WSDL) Message Schema (XSD) Transformation Rules (XSLT) Business Process Analysis (OV-2) Systems Communications Description (SV-2) Operational Activity Model (OV-5b) Requirements Document (SV-4) Architectural Impact Report Business Rules Service Constraints Information Exchange Description (OV-3) COI Ontology (RDF/OWL)

21 ▼ Purpose:  To be a collaborative web application through which users can publish, access, search, browse, map, and update ontologies and their terms.  Reference Implementation only ▼ Supports:  COI participants (e.g., ontologists, SMEs, and enterprise architects), developers and managers. Ontology Portals National Center for Biomedical Ontology BioPortal Marine Metadata Interoperability Ontology Registry and Repository Air Force Vocabulary OneSource Open Biomedical Ontologies Foundry Example Portals

22 Semantic Metadata Catalog and Portal Weather Community Integrated Surveillance Community JPDO User Interface Layer Semantic Metadata Portal External Systems GIIEP SWIM Semantic Processing Layer Artifact Catalog Existing SOA Registry ebXML UDDI Web Services Layer Service Registration and Discovery Access Semantic Metadata Catalog and Portal Architecture Semantic Metadata Catalog SemanticExternal Color Key: Future Service Registration and Discovery Integration of Federated Registry NextGen Ontology Community Ontology Portal Integration Layer

23 Sample Ontology Portals ▼ NCBO BioPortal  ▼ One Source  ▼ Marine Metadata Interoperabiligy (MMI) Ontology Registry and Repository (ORR) ▼

24 Run time application

25 SMB Approach: Semantics to Solutions SOA Foundation for Service Interoperability SOA Foundation for Service Interoperability Semantics Common Understanding of Business Concepts Semantics Common Understanding of Business Concepts Problems How I can improve Interoperability between different services and reduce system integration costs? I have already invested a lot in my SOA infrastructure, how do I leverage it for for Semantic Interoperability? How can Semantics help reduce service development cost and help my enterprise operations? Problems How I can improve Interoperability between different services and reduce system integration costs? I have already invested a lot in my SOA infrastructure, how do I leverage it for for Semantic Interoperability? How can Semantics help reduce service development cost and help my enterprise operations? Semantics Mediation Bus™ Runtime infrastructure enables semantic interoperability through common ontologies, even if the services are implemented using different data models and message standards. Semantics Mediation Bus™ Runtime infrastructure enables semantic interoperability through common ontologies, even if the services are implemented using different data models and message standards.

26 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

27 Service Consumer FAA Demo: Traditional SOA Original Track Data Provider Original Track Data Provider Google Earth Client

28 SOA Silos SLIDE 28 Excess time is spent interpreting data from different sources despite the usage of advanced IT techniques like Web Services FAA Flight Track Web Service AF Flight Track Web Service HR Army HR Marine Other Data Provider User Field Name: Commercial Flight Data : 122 Field Name: Commercial Flight Data : 122 Airline Code Lookup Table Data: UA Airline Code Lookup Table Data: UA Field Name: Flight of Interest Data: United 122 Field Name: Flight of Interest Data: United 122 Field Name: FlightID Data: UA122 Field Name: FlightID Data: UA122 Flight Track Display Reference Developer SME AF SME 1 1 Human Communication Custom Mapping 2 2 Custom Development 3 3 System Integration

29 Problem with Custom Development ▼ Discovery of Relevant Information ▼ Human in the Loop for Interoperability Assessment ▼ Custom Mapping and Custom Development  Often requires significant resources and takes a long time ▼ Change Management  Transformation often embed in code  Code and ontology could become disconnected

30 Service Consumer FAA Demo: SOA Silo Original Track Data Provider Original Track Data Provider Google Earth Client Air Force Alternate Track Data Provider Alternate Track Data Provider

31 SOA Infrastructure Service Consumer FAA Demo: Semantic Service Provisioning Original Track Data Provider Original Track Data Provider Google Earth Client Air Force Alternate Track Data Provider Alternate Track Data Provider Semantic Metadata Catalog Annotation Discover

32 Benefits of Semantic Service Provisioning ▼ Discovery of Relevant Information  Beyond traditional keyword search ▼ No Need for Human in the Loop for Interoperability Assessment  Machine readable ontologies describe relationships among concept ▼ Avoid Custom Mapping and Custom Development  Faster Development Lifecycle  Reduced Development Cost ▼ Built for Change  Allow transformations and business rules to be managed independent of the code  Consistent with Model Driven Architecture principals

33 Data Open Standard Compliance ▼ Web Ontology Language (OWL) ▼ Semantic Annotations for WSDL and XML Schema (SAWSDL) ▼ Minimal Service Model (MSM) and WSMO-Lite ▼ Extensible Stylesheet Language Transformations (XSLT) ▼ Web Service Definition Language (WSDL) XML URI XSLT Services WSDL REST Semantics OWL WSMO-Lite SAWSDL SOAP

34 Minimal Service Model Source:

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 35 WSDL XML Schema Import <xsd:ComplexType name=“FlightTrack” sawsdl:modelReference=“… …” sawsdl:liftingSchemaMapping=“…” sawsdl:loweringSchemaMapping=“…”> <xsd:ComplexType name=“FlightTrack” sawsdl:modelReference=“… …” sawsdl:liftingSchemaMapping=“…” sawsdl:loweringSchemaMapping=“…”> <operationname=“getFlightTrack” sawsdl:modelReference=“… …”> <operationname=“getFlightTrack” sawsdl:modelReference=“… …”> Enterprise Vocabulary ont:AirTrack a rdfs:Class … … ont:AirTrack a rdfs:Class … … svc:airTrackProvider svc:payload ont:AirTrack … … svc:airTrackProvider svc:payload ont:AirTrack … … SPARQL+XSLT XSLT

36 Alion Semantic Mediation Bus™ An ontology-based web services mediation component (Semantic Mediator) that enables services with different message formats to interoperate Embedding the Semantic Mediator in an Enterprise Service Bus (ESB) enables runtime semantic mediation within traditional SOA infrastructure, creating a Semantic Mediation Bus TM Enterprise Service Bus Registry/ Repository Traditional SOA infrastructure Semantic Mediation Infrastructure Semantic Mediator Protocol Adaption Message Transformation Message Routing Security Service Discovery Semantic Lookup and Interoperability Assessment Message Schema Mapping Semantic Annotation Metadata Management Web Service Proxy Common Ontology Semantic Mediation Bus TM

37 Semantic Mediation: HR Army FAA Web Service FAA Web Service Air Force Web Service HR Army HR Marine 3 rd Party Web Service User Semantic Mediation Bus™ Semantic Lookup Field Name: Commercial Flight Data : 211 Field Name: Commercial Flight Data : 211 Airline Code Lookup Table Data: UA Airline Code Lookup Table Data: UA Field Name: Flight of Interest Data: UA211 Field Name: Flight of Interest Data: UA211 Field Name: FlightID Data: United 211 Field Name: FlightID Data: United 211 Common Air Track Ontology Message Transformation Web Service Endpoint Flight Track Display Reference Dynamically Map Information to User Needs

38 Demo: Semantic Service Mediation SOA Infrastructure Service Consumer FAA Original Track Data Provider Original Track Data Provider Google Earth Client Air Force Alternate Track Data Provider Alternate Track Data Provider Semantic Metadata Catalog Annotation Semantic Discovery Interoperability Assessment Alion Semantic Mediation Bus™ Message Transformation Dynamic Service Endpoint

39 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.

40 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

41 Technical Architecture Enterprise Service Bus Semantic Mediation Bus Service Endpoint Registry/Repository OWL Ontology XML Schema SAWSDL Annotation Web Service Aggregation Proxy Semantic Lookup XML Schema WSDL SAWSDL Annotation Lifting and Lowering Rules Service Consumer Service 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 Extension API 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

42 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

43 The SMB Message ▼ 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  Ready to deployed now ▼ Streamline Service Integration  Shorten development lifecycle by eliminating the need for custom message mapping  Reduce maintenance cost by leveraging existing infrastructure