Using RDF

1. Data integration and
visualization
Ivan Ermilov
University of Leipzig
USING RDF

2. Agenda
• Data discovery
• Data conversion
• Data integration

3. Linked Data Lifecycle
http://stack.lod2.eu/blog/

4. DATA DISCOVERY

5. Data Discovery
• Ontologies
• Vocabularies
• Documents

6. Data Discovery: Ontologies
Specification of a conceptualization

7. Data Discovery: Ontologies

8. Data Discovery: Ontologies
http://swoogle.umbc.edu/
http://watson.kmi.open.ac.uk/WatsonWUI/

9. Data Discovery: Vocabularies
FOAF – Friend of a Friend:
• A Semantic Web Vocabulary used to describe people,
their activities and their relationships between one
another.
• It is becoming very popular for people who discover this
to setup and have their own FOAF profile.
• This vocabulary is the base from which other
vocabularies are extended.

10. Data Discovery: Vocabularies
http://xmlns.com/foaf/spec/

11. Data Discovery: Vocabularies

12. Data Discovery: Vocabularies
http://lov.okfn.org/dataset/lov/

13. Data Discovery: Documents
<http://www.linkedin.com/in/timbl> <http://purl.org/dc/terms/title> "Tim Berners-Lee - LinkedIn"@en .
_:node0 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/2006/vcard/ns#Address> .
_:node0 <http://www.w3.org/2006/vcard/ns#locality> "Greater Boston Area" .
<http://www.linkedin.com/in/timbl> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://www.w3.org/2002/12/cal/icaltzd#vcalendar> .
_:node1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/2002/12/cal/icaltzd#Vevent> .
_:node1 <http://www.w3.org/2002/12/cal/icaltzd#summary> "MIT" .
_:node1 <http://www.w3.org/2002/12/cal/icaltzd#description>
"Director, World Wide Web ConsortiumnnAlso, part time Prof in ECS at Southampton University, UK" .

14. Data Discovery: Documents
http://sindice.com/

15. Data Catalogs
• Community maintained registry exists
• Contains 362 data catalogs (growing)
• Based on CKAN data catalog platform
http://datacatalogs.org/

16. Data Catalogs
http://datacatalogs.org/

17. What is CKAN?
• Metadata repository with crowd-sourcing enabled
• Everybody can register and publish data about their datasets
• Developer-friendly web application
• Provides a well-documented API
• Easy to install, easy to use as your own metadata
repository

18. CKAN Architecture
Packages Resources
contain
And you can search
for them

19. The Data Hub

20. The Data Hub

21. Hub of Data

22. Hub of Data

23. CKAN API
• Well-documented
• http://docs.ckan.org/en/latest/api.html
• Covers everything you can do with the web interface
• You can write your own web interface
• OKFN maintained library for accessing API
• ckanclient (python)

24. CKAN API: Methods
• Retrieving data
• Creating new data
• Update existing data
• Delete existing data
• Data is: packages, resources, groups, tags, users etc.

25. CKAN API: Examples
ckan = CkanClient(base_location=ckan_api_url,
api_key=ckan_api_key)
package_list = ckan.package_list()
formats = []
for package in package_list:
resource_list = package[‘resources’]
for resource in resource_list:
if(not resource['format'] in formats):
formats.append(resource['format'])
return sorted(formats)
https://github.com/okfn/ckanclient

26. Use Case: CSV2RDF Conversion
• Framework for CSV2RDF conversion
• Crowd-sourcing enabled
• RDF Visualizations
https://github.com/earthquakesan/CSV2RDF-WIKI

27. CSV2RDF Conversion: Why CSV?

28. CSV2RDF Conversion: Data Quality

29. Data conversion

30. Data Conversion
• Structured: Relational Databases
• Semi structured: XML, HTML, XLS, CSV, APIs
• Unstructured: Raw text
PublicData.eu Statistics

31. XML
RDB
Spreadsheet
?
How does government
spending in certain sectors
relates to my company’s
earnings?
How does the historic
spending relates to the
current figures?
Give me report about all of
my customers across the
whole organization
Data Conversion

32. Custom
scripts
XML
RDB
Spreadsheet
?
Data Conversion
XPath
SQL
Result
aggregation

33. Merging data with RDF
XML
RDB
Spreadsheet
Once in RDF:
 Easily integrate your
data
 Concepts can be
mapped to one
another
 Query everything with
one W3C standard
language (SPARQL)

34. Merging Data with RDF: Example
• Blue App has model

35. • Red App has model
• Need to integrate Red & Blue models
Merging Data with RDF: Example

36. • Step 1: Merge RDF
• Same nodes (URIs) join automatically
Merging Data with RDF: Example

37. • Step 2: Add relationships and rules
• (Relationships are also RDF)
Merging Data with RDF: Example

38. • Step 3: Define Green model
• (Making use of Red
• & Blue models)
Merging Data with RDF: Example

39. • What the Blue app sees:
• No difference!
Merging Data with RDF: Example

40. • What the Red app sees
• No difference!
Merging Data with RDF: Example

41. RDF helps bridge other formats/models
• Producers and consumers may use different formats/models
• Rules can specify transformations
• Inference engine finds path to desired result model
RDF
Model
Transform
A1
A2
A3
B1
B2
C1
C2
X
Y
Z Ontologies
& Rules
Ontologies
& Rules
Ontologies
& Rules

42. RDB2RDF

43. Extract, Transform, Load (ETL)

44. Automatic Mapping

45. Semi-Automatic Mapping

46. R2RML

48. Sparqlify: Examples

49. Sparqlify: Examples

50. Sparqlify: Examples

51. Sparqlify: Examples

52. Sparqlify: Examples

53. Sparqlify: CSV2RDF
Prefix pdd: <http://data.publicdata.eu/>
Prefix pdo: <http://wiki.publicdata.eu/ontology/>
Create View Template DefaultMapping As
Construct {
?s ?p1 ?o1 ;
?p2 ?o2 ...
}
With
?s = uri(concat(pdd:,’csv-path/’,?rowId))
?p1 = uri(concat(pdo:, ?headingName1))
?o1 = plainLiteral(?1)
?p2 = ...
http://sparqlify.org/

54. Raw Text Processing: ConTEXT
●
No installation and configuration required.
●
Access content from a variety of sources
●
Instantly show the results of text analysis to users in a variety
of visualizations.
●
Allow refinement of automatic annotations and take feedback
into account
●
Provide a generic architecture where different modules for
content acquisition, natural language processing and
visualization can be plugged together.
http://rdface.aksw.org/nlp/hub.php

55. Processing Raw Text: ConTEXT

56. Data Integration

57. Definition
• In general, integration of multiple information systems
aims at combining selected systems so that they form
a unified new whole and give users the illusion of
interacting with one single information system

58. Semantic Data Integration

59. Federated SPARQL Queries
• Query processing involving multiple distributed data
sources, e.g. Linked Open Data cloud
DBpedia
New York
Times
Query both data collections in an integrated
way

60. Federated Query Processing
Federation mediator at the server
Virtual integration of (remote) data sources
Communication via SPARQL protocol
SPARQL
Data
Source
SPARQL
Data
Source
Federation
Mediator
SPARQL
Data
Source
Query

61. Federated Query Engines
Engine Name Implementation
language
License
FedX Java GNU A.G.P.L
SPLENDID Java L.G.P.L
LHD Java MIT
DARQ Java GPL
ANAPSID Python GNU G.P.L
ADERIS Java Apache

62. Data Visualization

63. LD Visualization Techniques

64. LD Visualization Techniques

65. LD Visualization Techniques

66. LD Visualization Techniques

67. Classification of Visualization
Techniques

68. Comparison of Values/Attributeshttp://goo.gl/IvsGbU
http://goo.gl/JeFhlM

69. Analysis of Relationships and
Hierarchies

70. Analysis of Relationships and
Hierarchies
http://rhizomik.net/dbpedia/treemap.jsp
http://lov.okfn.org/dataset/lov/

71. Analysis of Temporal and
Geographical Events http://lov.okfn.org/dataset/lov/details/vocabulary_dcterms.html

72. Analysis of Multidimensional Data
http://mbostock.github.io/protovis/ex/cars.html

73. Other Visualization Techniques

74. Applications of LD Visualization
Techniques

75. Tool Types

76. Tool Types

77. CubeViz

78. Facete

79. Thank you
Ivan Ermilov
iermilov@informatik.uni-leipzig.de
University of Leipzig
FOR YOUR ATTENTION