Toronto Semantic Web Meetup

1. Sharing Data on The Web
A Semantic Web Tutorial
James Leigh
@jamesrdf
james@3roundstones.com
February 2013

2. Towards Linked Open Data
●
On the Web with an open license ★
“It's great to have the data accessible on
the Web under an open license, however,
the data is locked-up in a document.
Other than writing a custom scraper, it's
hard to get the data out of the
document.”

3. Towards Linked Open Data
On the Web with an open license
●
★
Machine-readable data
★
●
“Splendid! The data is accessible on the
Web in a structured way (that is,
machine-readable), however, the data is
still locked-up in a document. To get the
data out of the document you depend on
proprietary software.”

4. Towards Linked Open Data
On the Web with an open license
●
★
Machine-readable data
★
●
Non-proprietary format
★
●
“Excellent! The data is not only available
via the Web but now everyone can use
the data easily. On the other hand, it's
still data on the Web and not data in the
Web.”

5. Towards Linked Open Data
●
On the Web with an open license ★
Machine-readable data
★
●
Non-proprietary format
★
●
●
RDF standards
“Wonderful! Now it's data in the Web. The★
(most important) data items have a URI and
can be shared on the Web. A native way to
represent the data is using RDF, however
other formats such as Atom can be
converted/mapped, if required.”

6. Towards Linked Open Data
On the Web with an open license
●
★
Machine-readable data
★
●
Non-proprietary format
★
●
●
RDF standards
●
Linked RDF
★
★
“Brilliant! Now it's data, in the Web linked to
other data. Both the consumer and the
publisher benefit from the network effect. ”

7. Path to Success
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Start easy
– Well curated
– Small dataset
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Reach out to developers
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Get others involved early
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Ensure internal benefit
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Maximize productivity
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Integrate related dataset

8. Choosing a License
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Allow modification?
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Require attribution?
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Permit commercial uses?
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Must others share alike?
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What jurisdiction?

9. Address Data Quality
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Completeness
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Conformity
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Consistency
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Accuracy
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Integrity
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Eliminate duplication

10. Put It On The Web
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Upload it and share ★
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Document what is available
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Document how to use it
– Solve a consumer need
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Encourage feedback
– Continues improvement

11. Make It Machine-readable
Simplify data structure
●
★
Don't include unstable identifiers
★
●
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Automate publishing

12. Use a Non-proprietary Format
Standardized formats
★
●
– CSV instead of excel
– XML instead of MDB ★
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Benefits: ★
– Accessibility
– Interoperability
– Reduce risk of
●
Confidential info
●
Software viruses

13. API Service
Data access layer
●
★
Atom Publishing Protocol
★
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Google Data Protocol
★
●
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Open Data Protocol
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Facebook Graph API
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Linked Data

14. The Web
Universal unidirectional links using URLs
●
★
Graph of nodes identified by URL
★
–
●
Cooperation without coordination
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It's simple nodes and Links
★

15. The Semantic Web
A universal scalable interconnection bus
●
★
Share and reuse data across
★
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– Community boundaries
– Application
★
– Enterprise

16. (re)Model the Data
Identify existing model
●
★
Reuse common vocabularies
★
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Model data relationships
★
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– Put aside particular needs of any application
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Diagram relationships
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Test assumptions with subject matter experts

17. Universal Identifiers
Others can reference things
★
●
●
The Web uses URL for
★
downloadable things
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Uses URI for real world things and
●
abstract concepts
Two references with the same URI
★
are the same thing
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Quick, easy and scalable look-up

18. Publish RDF
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RDF connects better than any other model ★
Cooperation without coordination
★
●
Data can be combined safely
★
●
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Mix of vocabularies
★

19. VoID Description
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De facto standard for describing Linked Data ★
Used in linked data catalogues
★
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Include provenance and attributions
★
●
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Associate consumers' license
★

20. RDF Schema
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Understand structure ★
of the graph
– Self-describing ★
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Define terms and ★
relationships ★
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Classes of things

21. Simple Knowledge Organization
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Controlled vocabularies ★
Taxonomies
★
●
Thesauri
★
●
★

22. Controlled Vocabularies
Strongly agree Mr. AB
★
● ●
●
●
BC
●
Agree
Ms. MB
★
●
●
●
Somewhat agree ●
NB
Neither agree nor Mrs. NL
★
● ● ●
disagree ●
NS
●
Miss. ON
Somewhat disagree
★
●
●
●
PE
●
Disagree ●
Dr. ●
QC
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Strongly disagree ●
SK
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NT
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NU
●
YT

23. Taxonomies
★
★
★
★

24. Thesauri
★
★
★
★

25. Web Ontology Language
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Property restrictions ★
Equivalences across
★
●
ontologies
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Constraints ★
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Automatic reasoners ★
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Annotations

26. Linked RDF
Linked your data to others
●
★
Adds more related data
★
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Add value to the data
★
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– By joining it to other data
★
★

27. Generating Data Websites
Give ordinary users direct access the data
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★
Templates to generate HTML
★
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– Generate static HTML offline
– Produce HTML on-demand
★
★
★

28. Social Responsibility
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Responsibility to maintain published data
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Publish frequency of data updates
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Have a persistence strategy
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Ensure data is accurate as possible
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Respond to reports of problematic data

29. Comments or Questions?