A Gentle Introduction to Linked Open Data. Linked Data Use Cases

1. Publishing and Using
Linked Open Data
Richard J. Urban, Ph.D.
School of Library and Information Studies
Florida State University
rurban@fsu.edu
@musebrarian
#lod4h

2. January 7, 2013
Monday’s Schedule
• 9:30 - 10:00 Class Session: Participant Introductions
• 10:00- 10:45 Class Session: A Gentle Introduction to Linked Data
• 10:45-11:00 am Break
• 11:00 am- Noon Class Session: Exploring Linked Data Use Cases
• Noon- 1 pm Lunch (on your own)
• 1:00-2:30 pm Class Session: A Gentle Introduction to Linked Data (con't)
• 2:30-2:45 pm Break
• 2:45-3:45pm Class Session: Participant Project Kick-off
• 4:00-5:00 pm Lecture: Seb Chan - Location: Ulrich Recital Hall, Tawes Fine Arts Building
• 5:30 pm-7:00 pm Graduate Student Networking Event
Hosted by CUNY and MITH
Location: MITH
0301 Hornbake Library (inside Non-Print Media)
Refreshments Provided
#lod4h

3. PARTICIPANT
INTRODUCTIONS
#lod4h

4. A GENTLE INTRODUCTION
TO LINKED DATA: PART I
#lod4h

5. A Web of Documents
Berners-Lee, T. (1989)
Information Management: A Proposal
http://goo.gl/xh36K
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6. World Wide Web
WWW - documents with simple relationships
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7. An HTML tree
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8. Document semantics
• XML (and HTML) provides a descriptive
markup for documents (including metadata
records)
• Even for more complex XML, like TEI, the
meaning of many elements is dependent
on it’s context within a document instance.
• Interpreting this context requires human
intervention.
#lod4h

9. Organizing the Web
• Human organization
• Crawl and Index
– Uses many of the methods used by digital
humanities scholars to extract information
from web documents.
• Page Rank
– Inferring importance from links
#lod4h

10. Database-driven Web:
Silos of Data
#lod4h 10

11. Data-driven documents
Data
Data
Data
Data
WWW - documents with simple relationships
#lod4h 11

12. •Federated (Z39.50)
•Aggregated
(Open Archives Initiative – Protocol for Metadata Harvesting)
•Application Programming Interface (API)
(service specific)
#lod4h 12

13. Data Semantics
• Often dependent on human interpretation
of documents/standards.
• Local data-provider interpretations not
always documented or available to data
consumers.
#lod4h

14. LINKED OPEN DATA
A New Vision in Two Parts
#lod4h

15. Linked Data Principles
1. Use URIs as names for things
2. Use HTTP URIs so that people can look up
those names.
3. When someone looks up a URI, provide useful
information, using the standards (RDF,
SPARQL)
4. Include links to other URIs. so that they can
discover more things.
#lod4h 15

16. “Things” = Resources
A resource can be anything that has identity.
Familiar examples include an electronic document, an image, a service
(e.g., "today's weather report for Los Angeles"), and a collection of
other resources. Not all resources are network "retrievable"; e.g.,
human beings, corporations, and bound books in a library can also be
considered resources.
The resource is the conceptual mapping to an entity or set of entities,
not necessarily the entity which corresponds to that mapping at any
particular instance in time. Thus, a resource can remain constant even
when its content---the entities to which it currently corresponds---
changes over time, provided that the conceptual mapping is not
changed in the process.
http://www.ietf.org/rfc/rfc2396.txt
#lod4h

17. Uniform Resource Identifiers
• More than a
Uniform Resource
Locator (URL)
• Proves a
mechanism to
name resources in
a way that works at
Internet scale.
http://en.wikipedia.org/wiki/Uniform_resource_identifier
#lod4h

18. De-referencing URIs
• When someone looks up a URI, provide useful
information, using the standards
(RDF, SPARQL)
• URIs can be used to name non-networked
resources (concepts, people, physical
objects, etc.)
• Useful if information about these objects can be
returned when the name is used.
• CoolURIs for the Semantic Web
http://www.w3.org/TR/cooluris/
#lod4h

19. Resource Description Framework
• A model for representing data
– An artificial language with a formal semantic
model
– Can be expressed using multiple syntaxes
– Simple grammar
• RDF “Triple”
– <subject> <predicate> <object>
– NAME verb Object
– Mona Lisa painted by Leonardo da Vinci
#lod4h

20. It’s a graph!
• That uses URIs
http://ex.org/monaLisa#
http://purl.org/dc/terms/creator/
http://ex.org/daVinci#
#lod4h 20

21. From a simple language, we can say complex things.
#lod4h 21

22. RDF Data Modeling
• RDF can be used with multiple tools for
modeling data
• Simple: RDF Schema (RDFS)
• Robust: Web Ontology Language (OWL)
– OWL-Lite
– OWL-Full
#lod4h

23. Limitations
• Best used for simple declarative
statements
– Difficult to express meta-assertions
i.e. “john believes that sally is 5’ tall”
– Data provenance/trust
– Negation “sally is not 5’ tall”
– Tenseless (need to explicitly model time)
– Modeling a “record” (named graphs)
#lod4h

24. SPARQL
• SPARQL Protocol and RDF Query
Language
– A query language for RDF
– Similar to SQL
– Implemented by RDF publication software
(Triplestore)
#lod4h

25. Link to Other Resources
• Include links to other URIs. so that they can
discover more things.
– Link to controlled vocabularies/ontologies
– Use existing RDFS/OWL schemas
– link different representations of the same
resources together
• Associate annotations with resources
#lod4h

26. The Linked Data so far
#lod4h 26

27. Linked Open Data Criteria
★ Available on the web (whatever format), but
with an open license
★★ Available as machine-readable structured data
(e.g. excel instead of image scan of a table)
★★★ as (2) plus non-proprietary format (e.g. CSV
instead of excel)
★★★★ All the above plus, Use open standards from
W3C (RDF and SPARQL) to identify things, so
that people can point at your stuff
★★★★★ All the above, plus: Link your data to other
people’s data to provide context
#lod4h

28. LINKED DATA USE CASES
#lod4h

29. Use Cases
• Linked Library Use Cases
http://www.w3.org/2005/Incubator/lld/XGR-
lld-usecase-20111025/
• DHWI Examples
http://www.diigo.com/user/musebrarian/dh
wi_example
#lod4h

30. A GENTLE INTRODUCTION
TO LINKED DATA: PART II
#lod4h

31. A Simple Start
• Friend of a Friend (FOAF)
http://www.foaf-project.org/
• A simple RDF vocabulary for describing
people and their relationships.
#lod4h

32. FOAF (Turtle) Syntax
@prefix : <http://xmlns.com/foaf/0.1/> .
<http://chi.cci.fsu.edu/person/rurban#>
:name "Richard J. Urban" ;
:givenname “Richard” ;
:familyname “Urban” ;
:website <http://chi.cci.fsu.edu/> ;
:workplacehomepage <http://slis.fsu.edu> ;
:workplacedirectory <http://directory.cci.fsu.edu/richard-urban/> ;
:publications <http://chi.cci.fsu.edu/person/rurban/publications> ;
:mbox_sha1sum <e122ce3b5475f25d5824e02574806b5e116b2662> ;
:weblog <http://www.inherentvice.net> .
#lod4h

33. • http://goo.gl/PgdqN
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34. FOAF <XML> Syntax
<?xml version="1.0"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:foaf="http://xmlns.com/foaf/0.1/">
<rdf:Description rdf:about="http://chi.cci.fsu.edu/person/rurban#">
<foaf:name>Richard J. Urban</foaf:name>
<foaf:givenname>Richard</foaf:givenname>
<foaf:familyname>Urban</foaf:familyname>
<foaf:website rdf:resource="http://chi.cci.fsu.edu/" />
<foaf:workplacehomepage rdf:resource="http://slis.fsu.edu" />
<foaf:workplacedirectory rdf:resource="http://directory.cci.fsu.edu/richard-urban/" />
<foaf:publications rdf:resource="http://chi.cci.fsu.edu/person/rurban/publications" />
<foaf:mbox_sha1sum rdf:resource="e122ce3b5475f25d5824e02574806b5e116b2662" />
<foaf:weblog rdf:resource="http://www.inherentvice.net" />
</rdf:Description>
</rdf:RDF>
#lod4h

35. #lod4h

36. Basic Turtle
• Terse RDF Triple Language
http://www.w3.org/TeamSubmission/turtle/
• Always start with a @prefix to declare a
namespace for each schema you will use
in your graph
– Can mix/match any published RDF schema
@prefix : <http://xmlns.com/foaf/0.1/> .
#lod4h

37. FOAF Properties
http://xmlns.com/foaf/spec/
• FOAF Core • Social Web – publications
– Agent – nick
– Person – currentProject
– mbox
– name – pastProject
– title – homepage
– img – weblog – account
– depiction (depicts) – openid – OnlineAccount
– familyName
– jabberID – accountName
– givenName
– knows – mbox_sha1sum – accountServiceHomepage
– based_near – interest
– PersonalProfileDocument
– age – topic_interest
– made (maker) – topic (page) – tipjar
– primaryTopic (primaryTopicOf)
– Project
– workplaceHomepage – sha1
– Organization – workInfoHomepage – thumbnail
– Group – schoolHomepage – logo
– member
– Document
– Image
#lod4h

38. Get Yourself a URI
• Can use a CoolURI based on your
homepage
• A mailto:email@org.org
• A “blank node”
_:me
(although these are discouraged for
Linked Data)
#lod4h

39. @prefix : <http://xmlns.com/foaf/0.1/> .
<http://chi.cci.fsu.edu/person/rurban#> URIs are always
enclosed in brackets
:name “Richard Urban” ;
Statements end with
a semi-colon…..
Properties start with
a colon. Strings are in quotes. Except the last
statement ends in a
period.
:homepage <http://chi.cci.fsu.edu> .
#lod4h

40. Hands-on
• Open a text editor.
• Write a FOAF description for yourself
using the Turtle Syntax.
– http://xmlns.com/foaf/spec/
– http://www.w3.org/TeamSubmission/turtle/
• Save the file with .ttl extension
– yourName.ttl
#lod4h

41. Publishing Your FOAF
• Put the file online, link it from your website.
• Publish using an RDF Triplestore
• Using FOAF-based plugins for
Wordpress/Drupal, etc.
#lod4h

42. Sesame Triple Store
• Let’s use my sandbox for this week:
– http://goo.gl/PgdqN
• Select the DHWI repository
• Select ADD
• Context baseURL: http://chi.cci.fsu/dhwi
• Past your Turtle into the RDF box.
• All of us together:
#lod4h

43. Linking our FOAF together.
• I know we just met, and this is crazy, but…
:knows <http://chi.cci.fsu.edu/person/rurban#>
• Add the URI of anyone else in the class
you know.
#lod4h

44. Some FOAF Humanities Use Cases
• Virtual International Authority File
http://www.viaf.org
• Social Networks and Archival Context
http://socialarchive.iath.virginia.edu/
• Linking Lives
http://data.archiveshub.ac.uk/page/person/nc
arules/skinnerbeverley1938-1999artist
• dbPedia
http://dbpedia.org/data/Abraham_Lincoln.n3
#lod4h

45. Beyond FOAF
• Organization Ontology
http://www.w3.org/TR/vocab-org/
• Encoded Archival Context-
Corporate, Personas, Families Ontology
http://goo.gl/oFIkW
• Other domain ontologies with
representations of people.
#lod4h

46. BREAK
#lod4h

47. Participant Projects
• What’s a small linked data project you can
complete in the next few days?
– Explore modeling questions
• Identify existing models
– Create/transform some data
• What data is already out there?
– Publish some examples
– Explore potential applications
#lod4h

48. Tonight’s Events
• 4:00-5:00pm Lecture: Seb Chan
– Location: Ulrich Recital Hall in Tawes Fine
Arts Building
• 5:30pm-7:00pm Graduate Student
Networking Event
– Hosted by CUNY and MITH; Location: MITH,
0301 Hornbake Library inside Non-Print
Media
– Refreshments Provided
#lod4h