1. Linked Open Data Martin Nečaský Faculty of Mathematics and Physics, Charles University in Prague

2. 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

3. 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

4. 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

5. Linked Data  data published on the Web according to four simple principles (introduced by sir T. B. Lee) 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 encoded in RDF, SPARQL 4.Include links to other URIs so that they can discover more things.

6. Things as first-class citizens Project CZ.2.16/2.1.00/22189 Prague City Prague Council Prague Demography Prague Budget Contract DIL/23/07/007302/2010

7. HTTP URIs for Things Project CZ.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/con tract/22189-01 http://risy.cz/ project/22189 czso.cz (Czech Statistical Office) http://registry. czso.cz/prague http://czso.cz/ prague http://czso.cz/pr ague/demogstat

8. Data about Things in RDF Client Playground Revitalization Authority: Prague Delivery date: 31.8.2011 Price: 28 444 000 CZK... Playground Revitalization 28444000 CZK dcterms:title pc:contracting Authority pc:agreedPrice gr:hasCurrency Value 31.8.2011 pc:estimated EndDate http://praha.eu/ contract/7302 http://praha.eu/ contract/7302/price http://praha.eu/ council

9. dcterms:title "Playground Revitalization" ; pc:estimatedEndDate "31.8.2011" ; pc:agreedPrice ; pc:contractingAuthority. gr:hasCurrency "CZK" ; gr:hasCurrencyValue "28444000". Data about Things in RDF Client Playground Revitalization Authority: Prague Delivery date: 31.8.2011 Price: 28 444 000 CZK... http://praha.eu/ contract/7302

10. 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 )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

11. Linking URIs of Related Things praha.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/con tract/22189-01 http://risy.cz/ project/22189 czso.cz (Czech Statistical Office) http://registry. czso.cz/prague http://czso.cz/ prague http://czso.cz/pr ague/demogstat c: hasBeneficiary a:fundedBy b:hasBudget http://praha.eu/ council d:hasDemography

12. Linking URIs of Related Things praha.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/con tract/22189-01 http://risy.cz/ project/22189 czso.cz (Czech Statistical Office) http://czso.cz/pr ague/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 b:hasBudget

13. Other examples  linked.opendata.cz  lekovaencyklopedie.cz

14. Thank You for Your Attention