Keynote at JISBD 2011

1. Towards The Next Wave Of
Services
Linked Services For The Web Of Data
Dr. Carlos Pedrinaci
Knowledge Media Institute - The Open University

2. Acknowledgements
• J. Domingue, J. Kopecky, D. Liu, M.
Maleshkova, H. Q. Yu, N. Li (OU)
• Jose Manuel Gómez Pérez, Guillermo
Alvaro (iSOCO)
• Irene Celino (CEFRIEL)
• SOA4All Project

3. Taken from the Introduction to Web Services by Oracle

4. Taken from the Introduction to Web Services by Oracle

5. What are the semantics
of every service?
... and most importantly ...
Where are they captured
for being processed?

6. Excerpt of OWL-S Excerpt of WSMO
Semantic Web SAWSDL, OWL-S and WSMO among
others have been proposed
Service Ontologies They have failed to gain adoption on the
Web

7. Semantic Web Services
• Predicated upon existing Web Services
which are not prevalent on the Web
• Complex to model
• Complex to process
• Hardly applicable
• Missing data in ontological terms

8. Web Services have
nothing to do with
the Web

9. Number of Web Services found by Seekda.com in the last 52 Months
... but Verizon has about 1,500
Services Internally ...

10. Web APIs are the Widely used and reused
Publicly available
new WEB services With a real business model behind them
Although harder automation!

13. Reality Check
• Survey based on 220 Web APIs from
ProgrammableWeb from 21 categories
• Types of Web APIs
– 45.5% REST, RPC 33.8%, Hybrid 20.7%
• 40% of Web APIs do not state the used HTTP method!
• Input and Output information
– 72% do not state the data type of the input
parameters
– 61% use optional parameters, 45% use default
values
– 90% have as output XML, 42% JSON
– 84% provide example request and 75% example
response

14. Linked Services
Exploiting the complementarity of
Services and Linked Data

15. “Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/”

16. 256 Datasets
30+ Billion Triples
Covering many diverse domains:
- Media
- Government
- Geography
- Life Sciences
...
“Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/”

17. Linked Data Principles
• Create a Web of Data by these 4 principles:
• Use URIs as names for things
• Use HTTP URIs so that people can look up
those names.
• When someone looks up a URI, provide
useful information, using the standards
(RDF*, SPARQL)
• Include links to other URIs

18. Taken from Steve Bratt - W3C

19. How can
Services help
Linked Data?

20. Developing Applications
The development of Linked Data
Applications is more an art than an
engineering discipline

21. Linked Services
• Linked Services are services described as
Linked Data (inputs, outputs, functionality...)
• In other words, it is Linked Data describing
reusable functionality
• With supporting machinery Linked Services are
Linked Data consumers and/or producers
• Core building blocks for Linked Data
Applications

22. 22

23. vi ce
S er

24. Where can I find
Linked Services?

25. Web of Documents Web of Data
http://iserve.kmi.open.ac.uk

26. Web of Documents Web of Data
http://iserve.kmi.open.ac.uk

27. Web of Documents Web of Data
http://iserve.kmi.open.ac.uk

28. Web of Documents Web of Data
http://iserve.kmi.open.ac.uk

29. “Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/”

30. “Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/”

33. How can I build a
Linked Data
application?
What’s the benefit?

34. SOA4RE
Mashes Linked Data and
Web APIs
Finds and Invokes Linked
Services on the Fly
Modularity and
Extensibility as a core
built-in feature

36. How can
Linked Data help
Services?

38. Issues with Services on
the Web
• Their semantics are unclear
• The data they consume and produce is
modelled in heterogeneous formats
• They are not Web-ready
• Their results are not globally
identified
• Their results are not de-referenceable

39. A typical Web API Pain HTML
Not machine processable
description Missing semantics

40. 36

41. 37

42. From Legacy Services to
Linked Services
• Services can be annotated using the
Web of Data as background knowledge
• This description makes the services
• More accessible (semantics)
• More applicable as they are expressed
in terms of existing vocabularies used
on the Web of Data

44. Supporting
Infrastructure

45. SOA4All Studio Combining distributed sources of data
about services to better support the life-
cycle of service-oriented applications

46. Related Tooling
SOA4All Studio

47. SWEET - MicroWSMO Editor
Related Tooling
SOA4All Studio

48. SWEET - MicroWSMO Editor
Related Tooling SOWER - WSMO-Lite Editor
Mashups Editor
SOA4All Studio

49. SWEET - MicroWSMO Editor
Related Tooling SOWER - WSMO-Lite Editor
Mashups Editor
SOA4All Studio SPICES - Invocation Interface

50. SWEET - MicroWSMO Editor
Related Tooling SOWER - WSMO-Lite Editor
Mashups Editor
SOA4All Studio SPICES - Invocation Interface

51. ... and the entire Covering the entire life-cycle of service-
based applications:
infrastructure - Composition, Execution, etc

52. Reflections
&
Outlook

54. Reflections
• Services need to be (in principle)
commercially profitable for a public
deployment
• Trust and fault tolerance will be
essential for their adoption
• Current climate favours openness for
creative collaborative innovation

55. Outlook
• Service-orientation can provide the
necessary engineering principles for
advanced Linked Data Applications
• Existing Linked Data and its principles
may provide the necessary support for
a Web-scale adoption of services
• Service-orientation is subject to the
network effect so ...

56. Put your piece in
the puzzle

57. Thanks for your
attention
Interested on an Internship, PhD?
Contact: c.pedrinaci@open.ac.uk