Linked Data life cycles

Dr. Michael Hausenblas, Linked Data Research Centre

DERI, NUI Galway

July 2011

What is a dataspace?

• Heterogeneous data sources• Distributed environment - proximity• Find and consume data• Update data

What is a DSSP and why does it matter?

• DSSP == Dataspace Support Platform

• Participants & relationships

• Services– Catalog & Browse– Search & Query– Index– Discovery

• Linked Data ecosystem is an open & standards-based real-world DSSP

Data management solutions

Base

d o

n [

Frankl

in:S

IGM

OD

05

]

Linked Data principles*

1. Use URIs to identify the “things” in your data

2. Use HTTP URIs so people and machines can look them up (on the Web)

3. When a URI is looked up, return a description of the thing

4. Include links to related things

* http://www.w3.org/DesignIssues/LinkedData.html

http://lod-cloud.net/

Linked Open Data cloud

triples distribution

links distribution

http://lod-cloud.net/state/

Linked Open Data cloud stats

The Challenge

• Classical data management approaches assume complete control over schema, data, and data generation

• The Web: distributed & open lacks control

• Requires a new model of life cycles

Linked Data life cycles

opendata.ie

LOD cloud

Neologism

DataCube

prefix.cc

Google Refine

RDB2RDF

VoID

DCAT

Sindice

CKAN

LATC 24/7

duke

Sig.ma

school explorer

data-gov.ie

Linked Data life cycles: data awareness

opendata.ie

LOD cloud

Neologism

DataCube

prefix.cc

Google Refine

RDB2RDF

VoID

DCAT

Sindice

CKAN

LATC 24/7

duke

Sig.ma

school explorer

data-gov.ie

‘database hugging disorder’

htt

p:/

/th

inkq

uart

erl

y.co

.uk/

01

-data

/a-d

ata

-sta

te-o

f-m

ind

/

Hans Rosling

TimBL’s 5-star plan for open data*

★ Make your data available on

the Web under an open license

★★ Make it available as structured data (Excel sheet instead of image scan of a table)

★★★ Use a non-proprietary format (CSV file instead of an Excel sheet)

★★★★ Use Linked Data format (URIs to identify things, RDF to represent data)

★★★★★ Link your data to other people’s data to provide context* http://lab.linkeddata.deri.ie/2010/star-scheme-by-example/

Linked Data life cycles: modeling

opendata.ie

LOD cloud

Neologism

DataCube

prefix.cc

Google Refine

RDB2RDF

VoID

DCAT

Sindice

CKAN

LATC 24/7

duke

Sig.ma

school explorer

data-gov.ie

http://linked-statistics.org/datacube/

http://vocab.deri.ie

http://neologism.deri.ie

http://schema.rdfs.org

Linked Data life cycles: publishing

opendata.ie

LOD cloud

Neologism

DataCube

prefix.cc

Google Refine

RDB2RDF

VoID

DCAT

Sindice

CKAN

LATC 24/7

duke

Sig.ma

school explorer

data-gov.ie

Publishing

http://lab.linkeddata.deri.ie/2010/grefine-rdf-extension/

Linked Data life cycles: discovery

opendata.ie

LOD cloud

Neologism

DataCube

prefix.cc

Google Refine

RDB2RDF

VoID

DCAT

Sindice

CKAN

LATC 24/7

duke

Sig.ma

school explorer

data-gov.ie

Discovery

• Model for dataset description: VoID vocabulary

• Users in industry and governments

• Published as W3C Notehttp://www.w3.org/TR/void

• Significant uptake in research

Describing Datasets

• General dataset metadata• Access metadata• Structural metadata• Describing linksets• Deployment and discovery of voiD files

Linked Data life cycles: integration

opendata.ie

LOD cloud

Neologism

DataCube

prefix.cc

Google Refine

RDB2RDF

VoID

DCAT

Sindice

CKAN

LATC 24/7

duke

Sig.ma

school explorer

data-gov.ie

Why going for the 5th star?

Central Contractor Registration (CCR)

Geonames

http://webofdata.wordpress.com/2011/05/22/why-we-link/

Pay-as-you-go integration

Fix Overall Data Integration

Effort

http://latc-project.eu/

Linked Data life cycles: use cases

opendata.ie

LOD cloud

Neologism

DataCube

prefix.cc

Google Refine

RDB2RDF

VoID

DCAT

Sindice

CKAN

LATC 24/7

duke

Sig.ma

school explorer

data-gov.ie

• Fingal County Council– Raising awareness re open data and demonstrating its value.– ODC2011 submission http://planning-apps.opendata.ie

• Local Government Management Agency (former LGCSB)– Advancing access to Open Data for Local Authorities – LD pilot for Management Service Indicators across Local Authorities

• Central Statistics Office, dissemination group– Boot-strapping data-gov.ie with statistical data.– school explorer - pilot

• Enterprise Ireland: National Cross Industry Working Group on Open Data

27

Use case: eGov Ireland

School explorer

Linked Data life cycles

opendata.ie

LOD cloud

Neologism

DataCube

prefix.cc

Google Refine

RDB2RDF

VoID

DCAT

Sindice

CKAN

LATC 24/7

duke

Sig.ma

school explorer

data-gov.ie

Challenges• Schema mapping, matching, alignment

[Hausenblas:DBKDA10]

• Write-enable the LD world [Berners-Lee:DERITR09]

• Authentication and authorisation in a distributed setuphttp://www.w3.org/2005/Incubator/webid/

• REST-alignment of Linked Data[Wilde:WEWST09]

• Dataset dynamics[Umbrich:LDOW10]

References[Franklin:SIGMOD05] M. J. Franklin, A. Y. Halevy, and D. Maier, From databases to dataspaces: a new

abstraction for information management. SIGMOD Record, 34(4):27–33, 2005.

[Berners-Lee:DERITR09] T. Berners-Lee, R. Cyganiak, M. Hausenblas, J. Presbrey, O. Seneviratne, and O. Ureche.On Integration Issues of Site-Specific APIs into the Web of Data. DERI Technical Report, 2009.

[Hausenblas:DBKDA10] M.Hausenblas and Marcel Karnstedt. Understanding Linked Open Data as a Web-Scale Database. Second International Conference on Advances in Databases, Knowledge, and Data Applications, 2010.

[Wilde:WEWST09] E. Wilde and M. Hausenblas. RESTful SPARQL? You Name It! Aligning SPARQL with REST and Resource Orientation. Fourth Workshop on Emerging Web Services Technology Workshop at European Conference on Web Services, Eindhoven, The Netherlands, 2009.

[Umbrich:LDOW10] J. Umbrich, M. Hausenblas, A. Hogan, A. Polleres, and S. Decker. Towards Dataset Dynamics: Change Frequency of Linked Open Data Sources. Third International Workshop on Linked Data on the Web at 19th International World Wide Web Conference, Raleigh, North Carolina, USA, 2010.

See also ...

• The Linked Open Data cloudhttp://lod-cloud.net

• Linked Data core specificationshttp://linkeddata-specs.info

• Enabling cross-boundary access to data sourceshttp://enable-cors.org

• Linked Open Data 5-star deployment scheme

http://lab.linkeddata.deri.ie/2010/star-scheme-by-example/