005 Day3-semantic te.. - Buffalo Ontology Site

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14 Δεκ 2013 (πριν από 3 χρόνια και 6 μήνες)

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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

Semantic

External

Color Key:

Future

Service

Registration

and Discovery

Integration

of

Federated

Registry

NextGen
Ontology
Community

Ontology
Portal

Integration Layer

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

SOA

Foundation for Service Interoperability

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?


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
Track

Web
Service

HR
Army

HR
Marine

Other
Data
Provider

User

Field Name:

Commercial Flight

Data
:
122

Airline Code Lookup Table

Data:
UA

Field Name
:
Flight of
Interest

Data:
United 122

Field Name:

FlightID

Data:
UA122

Flight
Track
Display

Reference

Developer

SME

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

Alternate

Track Data
Provider

31

SOA

Infrastructure

Service Consumer

FAA

Demo: Semantic Service Provisioning

Original

Track Data
Provider

Google Earth
Client

Air Force

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:
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
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

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

Airline Code Lookup Table

Data:
UA

Field Name:
Flight of
Interest

Data:
UA211

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

Google Earth
Client

Air Force

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

Service
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 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


I
ncorporation
of unanticipated sources in
business intelligence


E
nhancement
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