Linked Open DataMartin NečaskýFaculty of Mathematics and Physics, Charles University in Prague

Web Applications Eco-system Linked Data helps to create an eco-system of web

applications which publish, enrich and consume data about things in one shared global data space

Shared Global Data Space on the Web (Web of Data)

App 1

App 2

App 3

App 4

App 5

App 4

Web of Documents

Current Web (of Documents) provides lot of data about Prague. Problems• Data about Prague encoded in documents

(HTML, XLS, CSV, XML, PDF, ...) distributed across the Web

• Most documents intended for humans not computers

• Data about Prague and related things not linked

• Therefore, automated processing of data about Prague published on the Web is hard

http://monitor.statnipokladna.cz

Prague budget

http://registry.czso.cz

Basic info about Prague

http://www.praha.eu

Prague public contracts

http://www.czso.cz

Demography of Prague

http://www.risy.cz

EU funded projects in Prague

Web of Documents

Try to search for this information on the current Web• Top 100 suppliers of Prague with

headquarters outside of Prague region.• Money spent in Prague for new children

playgrounds in the last 5 years per one child.

• Organizations in Prague funded by EU structural funds and their top 100 suppliers. http://monitor.statnipokladna.cz

Prague budget

http://registry.czso.cz

Basic info about Prague

http://www.praha.eu

Prague public contracts

http://www.czso.cz

Demography of Prague

http://www.risy.cz

EU funded projects in Prague

Linked Data data published on the Web according to four

simple principles (introduced by sir T. B. Lee)1. Use URIs as names for things2. Use HTTP URIs so that people can look up those

names.3. When someone looks up a URI, provide useful

information encoded in RDF, SPARQL4. Include links to other URIs so that they can

discover more things.

Things as first-class citizens

ProjectCZ.2.16/2.1.00/22189

Prague City

Prague Council

Prague Demography

Prague Budget

ContractDIL/23/07/007302/2010

HTTP URIs for Things

ProjectCZ.2.16/2.1.00/22189

praha.eu (Prague)http://

praha.eu/contract/7302

http://praha.eu/council

http://praha.eu/city

mfcr.cz (Ministry of Finance)

http://mfcr.cz/prague/budget

http://mfcr.cz/prague

risy.cz (Regional Information Service)

http://risy.cz/location/prague

http://risy.cz/contract/22189-

01

http://risy.cz/project/22189

czso.cz (Czech Statistical Office)

http://registry.czso.cz/prague

http://czso.cz/prague

http://czso.cz/prague/

demogstat

Data about Things in RDF

Client

Playground RevitalizationAuthority: PragueDelivery date: 31.8.2011Price: 28 444 000 CZK...

Playground Revitalization

28444000 CZK

dcterms:titlepc:contracting

Authority

pc:agreedPrice

gr:hasCurrencygr:hasCurrencyValue

31.8.2011

pc:estimatedEndDate

http://praha.eu/

contract/7302

http://praha.eu/

contract/7302

http://praha.eu/contract/7302/price

http://praha.eu/council

<http://www.praha.eu/contract/7302> dcterms:title "Playground Revitalization" ;pc:estimatedEndDate "31.8.2011" ;pc:agreedPrice <http://www.praha.eu/contract/7302/price> ;pc:contractingAuthority <http://www.praha.eu/council> .

<http://www.praha.eu/contract/7302/price>gr:hasCurrency "CZK" ;gr:hasCurrencyValue "28444000" .

Data about Things in RDF

Client

Playground RevitalizationAuthority: PragueDelivery date: 31.8.2011Price: 28 444 000 CZK...

http://praha.eu/

contract/7302

Vocabularies published RDF data would be hardly interpretable when

each publisher would use proprietary predicates therefore, standardized (or at least widely used) predicates

should have priority before proprietary ones e.g. Dublin Core, Good Relations, FOAF, schema.org, ... or more specific ones for public procurement

• e.g., Public Contracts Ontology (http://purl.org/procurement/public-contracts )

predicates are defined in so called vocabularies (or ontologies) note: ontology is a special case of vocabulary, it contains more detailed reasoning

rules which is out of scope of this lecture note: not only predicates but also classes (= types of things) are defined in

vocabularies/ontologies

Linking URIs of Related Thingspraha.eu (Prague)

http://praha.eu/

contract/7302

http://praha.eu/city

mfcr.cz (Ministry of Finance)

http://mfcr.cz/prague/budget

http://mfcr.cz/prague

risy.cz (Regional Information Service)

http://risy.cz/location/prague

http://risy.cz/contract/22189-

01

http://risy.cz/project/22189

czso.cz (Czech Statistical Office)

http://registry.czso.cz/prague

http://czso.cz/prague

http://czso.cz/prague/

demogstat

c: hasBeneficiary

a:fundedBy

b:hasBudgethttp://praha.eu/council

d:hasDemography

d:hasDemography

Linking URIs of Related Thingspraha.eu (Prague)

http://praha.eu/

contract/7302

mfcr.cz (Ministry of Finance)

http://mfcr.cz/prague/budget

http://mfcr.cz/prague

risy.cz (Regional Information Service)

http://risy.cz/contract/22189-

01

http://risy.cz/project/22189

czso.cz (Czech Statistical Office)

http://czso.cz/prague/

demogstat

c:hasBeneficiary

a:fundedBy

http://praha.eu/city

http://risy.cz/location/prague

http://registry.czso.cz/prague

http://czso.cz/prague

http://praha.eu/council

owl:sameAs

owl:sameAs

b:hasBudget

Other examples linked.opendata.cz lekovaencyklopedie.cz

Thank You for Your Attention