overview of semantic tools
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Overview of Semantic Tools . Semantic Technology Boot Camp Day 3. Overview. Categories of Semantic Tools Category Overview Purpose & Role in Architecture Example Tools Tradeoffs and Evaluation Criteria. Categories of Semantic Tools. RDF Parsers Triplestores - PowerPoint PPT PresentationTRANSCRIPT
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 PortalWeather
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
Ser
vices
Lay
er
Service Registration and Discovery
Access
Semantic Metadata Catalog and Portal Architecture
Semantic Metadata Catalog
Semantic ExternalColor Key:
Future
Service Registration and Discovery
Integration of Federated Registry
NextGen Ontology
Community Ontology Portal In
tegr
atio
n La
yer
23
Sample Ontology Portals
▼ NCBO BioPortal http://bioportal.bioontology.org/
▼ One Source http://onesource.afc2ic.org/
▼ Marine Metadata Interoperabiligy (MMI) Ontology Registry and Repository (ORR)
▼ http://mmisw.org/
24
Run time application
25
SMB Approach: Semantics to Solutions SOAFoundation for Service Interoperability
SemanticsCommon 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?
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
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 TrackWeb
Service
HR ArmyHR
Marine
Other Data
Provider
User
Field Name:Commercial FlightData: 122
Airline Code Lookup TableData: UA
Field Name: Flight of InterestData: United 122
Field Name:FlightIDData: UA122
Flight Track
DisplayReference
DeveloperSME
AF SME
1
1
Human Communication
Custom Mapping
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
Google Earth Client
Air Force
AlternateTrack Data
Provider
31
SOA Infrastructure
Service Consumer FAA
Demo: Semantic Service Provisioning
Original Track Data
Provider
Google Earth Client
Air Force
AlternateTrack 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 URIXSLT
Services
WSDL REST
Semantics
OWL WSMO-LiteSAWSDL
SOAP
34
Minimal Service Model
Source: http://cms-wg.sti2.org/minimal-service-model/
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=“…”>
<operation name=“getFlightTrack” sawsdl:modelReference=“… …”>
<input message=”…”>
Enterprise Vocabulary
ont:AirTrack a rdfs:Class … …
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 BusTM
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 BusTM
37
Semantic Mediation:
HR Army
FAAWeb
Service
Air ForceWeb
Service
HR ArmyHR
Marine
3rd PartyWeb
Service
User
Semantic Mediation
Bus™
Semantic Lookup
Field Name:Commercial FlightData: 211
Airline Code Lookup TableData: UA
Field Name: Flight of Interest Data: UA211
Field Name:FlightIDData: United 211
Common Air Track Ontology
Message Transformation
Web Service Endpoint
Flight Track
DisplayReference
Dynamically Map Information to User Needs
38
Demo: Semantic Service Mediation
SOA InfrastructureService Consumer FAA
Original Track Data
Provider
Google Earth Client
Air Force
AlternateTrack Data
Provider
Semantic Metadata Catalog
Annotation
Semantic DiscoveryInteroperability Assessment
Alion Semantic Mediation Bus™
Message TransformationDynamic
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 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 RulesLifting 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
nsio
n AP
I
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