Semantic Web Technologies for
Service Composition
Dragan Gašević
Athabasca University
Email: dgasevic@acm.org

(How) Are
semantic technologies
related to
service composition?

Topics to discuss about
Semantic Web and Ontologies
Semantic Web Services
Development of Service Compositions
Conclusion

Part I
Ontologies and MDE
- Basics -

Semantic Web
To create a universal medium for the exchange of data.
… to smoothly interconnect
personal information management,
enterprise application integration and
the global sharing of
commercial, scientific and cultural data.
Semantic Web Activity Statement
http://www.w3.org/2001/sw/Activity

Musician
plays records
Instrument plays at Album
attends
Admirer Event
rdf:type
rdf:type
< musician: Musician
rdf:ID="urn:rdf:969914d5ca929194ea18787de32c66
5a-1"> musician:records
RDF …
<musician:name>Eric Clapton</musician:name>
<musician:records rdf:resource =
"http://www.guitar.org/legendaryrecordings/EC#urn:r <album: Album
df:958804d5ca918084ea17676de21c887a-0"/> rdf:ID="urn:rdf:958804d5ca918084ea17676de21
… c887a-0">
</musician:Musician> …
<album:title>Unplugged</album:title>
<album:year>1992</album:year>
…
</album:Album>

What is an ontology?
Important definition (Hendler, 2001)
a set of knowledge terms, including
vocabulary
semantic interconnections
some simple rules of inference and
logic for some particular topic

Semantic Web
Ontologies: Interconnecting applications
Shared domain conceptualizations

Ontology languages
enable reasoning!
Not ontologies themselves.
Logic-based foundation and reasoning
No agreement about reasoning entailment

Part II
Semantic Web Services

Automation of
service discovery,
Semantic Web Services composition,
invocation, and
monitoring
Envisioned evolution of the Web
Computation Web Services Semantic
UDDI, WSDL, SOAP Web Services
Content Web Semantic Web
HTML, HTTP RDF(S), OWL, WSML
Syntax Syntax
http://www.wsmo.org/TR/d17/v0.2/

Semantic Web Services
SWS descriptions languages
Semantic Annotations for WSDL Recommendation
and XML Schema (SAWSDL)
Web Service Semantics (WSDL-S)
W3C Submissions
Ontology Web Language for Services (OWL-S)
Web Service Modeling Ontology (WSMO)
Semantic Web Service Ontology (SWSO)

SAWSDL : An extension of WSDL
http://lsdis.cs.uga.edu/projects/meteor-s/wsdl-s/WSDL-S-W3C-ppt.ppt
<Operation> <Operation>
<Input1> <Input2>
<Output1> <Output2>
SAWSDL Web service 1 Web service 2
Composition
Operation:
buyTicket
Input1:
<Operation>
TravelDetails
Output1:
Confirmation <Input1>
Operation: Semantic UDDI
cancel Ticket Search <Output1>
Input1:
TravelDetails Service Template
Output1: Publish
Confirmation
Annotations

http://www.wsmo.org/TR/d17/v0.2/
Web Service Modeling Ontology
A Conceptual
Model for SWS
A Formal Language for WSMO Execution Environment
A Rule-based Language for SWS for WSMO

Current State
Automation of service
Discovery
WSMO-MX, OWLS-MX, SAWSDL-MX – DFKI
iMatcher – based on iSPARQL
Composition
IRS, WSMO Studio
Invocation
Monitoring

How do we develop
compositions?

Part III
Service Compositions in
Development Processes

End-user development: AMICO
http://amico.sourceforge.net/

End-user Development: AMICO
http://amico.sourceforge.net/
Sequence
Sequence
f
Parallel Split
Exclusive choice
f
Simple merge

Google maps (with AJAX HTTP connection to AMICO)
End-user development
Sequence
Sequence
f
Parallel Split
http://amico.sourceforge.net/
Exclusive choice
f
Simple merge

Not quite Semantic Web!
But, some very useful lessons learned
No discovery – variable names
Ontologies and discovery engines
Mediation is still a problem

Compositions are
part of end-user apps
User interaction and user tasks are involved

Linked Data
http://linkeddata.org/static/images/lod-datasets_2009-03-05-scaled.png

Linked Data
SPARLQ end points are
already services
They enable semantic-rich data mash-ups
http://linkeddata.org/static/images/lod-datasets_2009-03-05-scaled.png

Potluck
From [Huynh et al, 2008]
David F. Huynh, Robert C. Miller, David R. Karger: Potluck: Data mash-up tool for casual users. J. Web Sem. 6(4): 274-282 (2008)

Potluck
From [Huynh et al, 2008]
David F. Huynh, Robert C. Miller, David R. Karger: Potluck: Data mash-up tool for casual users. J. Web Sem. 6(4): 274-282 (2008)

Composing Services: WebML
Start from business processes (in BPMN)
From [Brambilla et al, 2008]
Marco Brambilla, Stefano Ceri, Irene Celino, Dario Cerizza, Emanuele Della Valle, Federico Michele Facca, Andrea Turati,
Christina Tziviskou: Experiences in the Design of Semantic Services Using Web Engineering Methods and Tools. J. Data
Semantics 11: 1-31 (2008)

Composing Services: WebML
End-users interact with discovery engines
From [Brambilla et al, 2008]
Mediation another key challenge
Marco Brambilla, Stefano Ceri, Irene Celino, Dario Cerizza, Emanuele Della Valle, Federico Michele Facca, Andrea Turati,
Christina Tziviskou: Experiences in the Design of Semantic Services Using Web Engineering Methods and Tools. J. Data
Semantics 11: 1-31 (2008)

Software
Language Engineering
Language design and transformations

Context-awareness
Challenges
User modeling – preferences, goals, etc.
Learning from experience of other users

Families of Service Compositions
Domain engineering
Feature modeling
Annotation of features
Services discovery

Families of Service Compositions
Application Engineering
Description logic-based staged configuration
User functional and non-functional requirements
Combining with soft-requirements – fuzzy DL
Transforming configuration into WSMO
Run-time adaptation

Semantic techs can be
useful for automation
But, better understanding is needed
Applications vs. service compositions
Service-oriented app. lifecycles
Adaptivity of service-oriented applications
Software languages are needed

3rd International Conference on
Software Language Engineering
http://planet-sl.org/sle2010/

Thank you!
Questions?