Downloaded 12 times
![So, how to lift data ?
How to publish data on the Web as linked-
data ?
● Basic principles Tim Berners Lee [2006] (Design Issues)
– Use URIs to identify things (not only documents)
– Use HTTP URIs
– When dereferecing URIS, return a description of the
ressource
– Include links to other ressources on the Web](https://image.slidesharecdn.com/datalift-a-catalyser-for-the-web-of-data-fosdem-05-02-2011-110207114138-phpapp01/75/Datalift-a-catalyser-for-the-web-of-data-fosdem-05-02-2011-8-2048.jpg)
Uploaded byDatalift
Datalift a-catalyser-for-the-web-of-data-fosdem-05-02-2011
Datalift is a project that aims to catalyze the publication and interconnection of data on the web. It provides tools and services to help with various steps in the data publication process including: - Dataset publication and conversion tools to automate publishing raw data as RDF - Infrastructure for storing and querying published RDF data - Linkage tools to interconnect published datasets by finding equivalence links between resources - Applications that visualize and make use of published and interlinked data The goal is to make it easier for organizations to publish their data on the web in a way that is machine-readable and interoperable through the use of semantic web standards and vocabularies. This will help realize the promises of
More Related Content
Similar to Datalift a-catalyser-for-the-web-of-data-fosdem-05-02-2011
Datalift a-catalyser-for-the-web-of-data-fosdem-05-02-2011
- 1. Datalift: A Catalyserfor the Web of Data François Scharffe LIRMM/CNRS/University of Montpellier [email protected] @lechatpito With the help of the Datalift team And the support of the French National Research Agency FOSDEM 5/02/2011 1
- 2. The data revolutionis on its way ! As Open Data meets the Semantic Web
- 3. The promises oflinked-data
- 4. Richer Applications Linked DataLite | the Web on Steroids 1.0 (iPhone)
- 5. Richer applications BBC Programmes
- 6. More precise searchand QA
- 7. Making your data5 stars http://www.w3.org/DesignIssues/LinkedData.html
- 8. So, how tolift data ? How to publish data on the Web as linked- data ? ● Basic principles Tim Berners Lee [2006] (Design Issues) – Use URIs to identify things (not only documents) – Use HTTP URIs – When dereferecing URIS, return a description of the ressource – Include links to other ressources on the Web
- 9. Welcome aboard thedata lift Published and interlinked data on the Web Applications Interconnexion Publication infrastructure Data convertion Vocabulary selection Raw data
- 10. Datalift Datasets publication R&D toautomate the publication process Tool suite to help publish data Training, tutorials, data publication camps
- 11. st 1 floor - Selection SemWebPro 18/01/2011 11
- 12. Les vocabulaires demes amis … Ø What is a (good) vocabulary for linked data ? § Usability criterias Simplicity, visibility, sustainability, integration, coherence … Ø Differents types of vocabularies § metadata, reference, domain, generalist … § The pillars of Linked Data : Dublin Core, FOAF, SKOS Ø Good and less good practices § Ex : Programmes BBC vs legislation.gov.uk § Vocabulary of a Friend : networked vocabularies Ø Linguistic problems § Existing vocabularies are in English at 99% § Terminological approach :which vocabularies for « Event » « Organization »
- 13. Did you say« vocabulary » … And why not « ontology »? § Or « schema » ou « metadata schema »? § Ou « model » (data ? World ?) Ø All these terms are used and justifiable They are all « vocabularies » § The define types of objects (or classes) and the properties (oo attributes) atttached to these objects. § Types and attributes are logically defined and named using natural language § A (semantic) vocabulary is an explicit formalization of concepts existing in natural language SemWebPro 18/01/2011 13
- 14. Vocabularies for linkeddata Ø Are meant to describe resources in RDF Ø Are based on one of the standard W3C language § RDF Schema (RDFS) • For vocabulaires without too much logical complexity § OWL • For more complex ontological constructs § These two languages are compatible (almost) Ø The can be composed « ad libitum » § One can reuse a few elements of a vocabulary § The original semantics have to be followed
- 15. What makes agood vocabulary ? Ø A good vocabulary is a used vocabulary § Data published on CKAN give an idea of vocabulary usage § Exemple : v list of datasets using FOAF http://xmlns.com/foaf/0.1/ Ø Other usability criterias § Simplicity and readability in natural language § Elements documentation (definition in natural language) § Visibility and sustainability of the publication § Flexibility and extensibility § Sémantique integration (with other vocabularies) § Social integration (with the user community)
- 16. A vocabulary isalso a community Ø Bad (but common) practice ● Build a lonely vocabulary – For example as a research project – Without basing it on any existing vocabulary § To publish it (or not) and then to forget about it § Not to care about its users Ø A good vocabulary has an organic life § Users and use cases § Revisions and extensions § Like a « natural » vocabulary
- 17. Types of vocabularies ØMetadata vocabularies § Allowing to annotate other vocabularies • Dublin Core, Vann, cc REL, Status Ø Reference vocabularies § Provide « common » classes and properties • FOAF, Event, Time, Org Ontology Ø Domain vocabularies § Specific to a domain of knowledge • Geonames, Music Ontology, WildLife Ontology Ø « general » vocabularies § Describe « everything » at an arbitrary detail level • DBpedia Ontology, Cyc Ontology, SUMO
- 18. Vocabulary of aFriend Ø http://www.mondeca.com/foaf/voaf Ø A simple vocabulary... Ø To represent interconnexions between vocabularies Ø A unique entry point to vocabularies and Datasets of the linked-data cloud Linked Data Cloud Ø Ongoing work in Datalift
- 19. nd 2 floor - Conversion SemWebPro 18/01/2011 19
- 20. URL Design etURL Pattern Ø Good practices for linked-data § Ressource: http://dbpedia.org/resource/Paris § Document: http://dbpedia.org/page/Paris § Data: http://dbpedia.org/data/Paris Ø … served using content negociation
- 21. URI Pattern inREST Ø Les services REST (Representational State Transfer) manipulent des ressources et les URLs sont principalement utilisés pour adresser ces ressources Ø Une URI de base: § http://www.example.com/bookstore/ Ø Une ressource à un URL unique: (retrieve, update, create, delete) § http://www.example.com/bookstore/books/ISBN123 Ø Notion de collection: (list, replace, create, delete) § http://www.example.com/bookstore/books
- 22. Convertion tools toRDF Ø How is the raw data to be converted ? § Relational Database ? § (Semi-)structured formats ? § Programmatic acces (API) ? Ø There are solutions for all cases
- 23.
- 24. Triplify: Relational datato JSON/RDF Ø Extract a folder in your Webapp: http://sourceforge.net/projects/triplify/ Ø Modify a config file: § SQL query … URI pattern § PHP lover!
- 25.
- 26.
- 27. RDF extension forGoogle Refine Ø A graphical extension for Google Refine allowing to export the clean data as RDF http://lab.linkeddata.deri.ie/2010/grefine-rdf-extension/ Annual pay rate - including Name Job Title Grade Organization Notes taxable benefits and allowances Chief Executive Asset Protection £150,000 - Stephan Wilcke Officer Agency £154,999 Asset Protection £165,000 - Jens Bech Chief Risk Officer No pension Agency £169,999 Chief Invesment Asset Protection £165,000 - Ion Dagtoglou No pension Officer Agency £169,999 Chief Credit Asset Protection £130,000 - Brian Scammell 4 days per week Officer Agency £134,999
- 28.
- 29. rd 3 floor - Publication SemWebPro 18/01/2011 29
- 30. Publication components Querying Browsing SPARQL REST endpoint Alimentation Inference Engine RDF storage Alimentation Alimentation A few products Virtuoso, Sesame, Mulgara, 4store OWLIM, AllegroGraph, Big Data,Jena
- 31. Named graphs Ø Rdfgraphs are bags of triples, everything is mixed 1 Ø Delete on a graph 2 Ø SPARQL queries define 3 5 graphs 9 6 11 10 8 12 4 7 13 16 14 15
- 32. Inference 1 3 2 5 Ø Generating triples from other triples 9 6 10 11 8 Ø Deduction mechanism 12 4 7 13 § Men are mortals, Socrates is a man, so Socrates is 16 mortal 14 15 Ø Allows to avoid exhaustivity, give sense to defining hierarchies Ø Constraints: cardinality, NFPs, ...
- 33. Analyse des RDFStore : la méthode QSOS Ø Qualification and Selection of Open Source Software § Projet Open Source sur des solutions open source § http://www.qsos.org Ø Objectifs de QSOS § Qualifier des logiciels § Comparer des solutions après avoir défini des exigences et en pondérant les critères § Sélectionner le produit le plus adapté par rapport à un besoin Ø QSOS fournit § Une méthode objective et formalisée § Un référentiel d’études disponibles § Des outils facilitant le déroulement de la méthode
- 34. th 4 floor - Interconnexion SemWebPro 18/01/2011 34
- 35. Linked data andinterconnexions Ø Without links there is no Web but data silos Ø Links can be part of the datasets design (reference datasets) Ø Links can be found after the publication: equivalence links between resources
- 36. Comment interconnecter sesdonnées ?
- 37. Tools Ø RKB-CRS Acoreference resolution service for the RKB knowledge base Ø LD-mapper A linkage tool for datasets described using the Music Ontology Ø ODD Linker A linkage tool based on SQL Ø RDF-AI Multi purpose data linkage and fusion Ø Silk et Silk LSL Linkage tool and linkage specification language Ø Knofuss architecture Datasets linkage and fusion
- 38. Exemple Silk specification <Silk> <Interlink id="cities"> <Prefix id="rdfs" namespace= <LinkType>owl:sameAs</LinkType> "http://www.w3.org/2000/01/rdf-schema#" /> <SourceDataset dataSource="dbpedia" var="a"> <Prefix id="dbpedia" namespace= <RestrictTo> "http://dbpedia.org/ontology/" /> ?a rdf:type dbpedia:City <Prefix id="gn" namespace= </RestrictTo> "http://www.geonames.org/ontology#" /> </SourceDataset> <TargetDataset dataSource="geonames" var="b"> <DataSource id="dbpedia"> <RestrictTo> <EndpointURI>http://demo_sparql_server1/sparql ?b rdf:type gn:P </EndpointURI> </RestrictTo> <Graph>http://dbpedia.org</Graph> </TargetDataset> </DataSource> <LinkCondition> <AVG> <DataSource id="geonames"> <Compare metric="jaroSimilarity"> <EndpointURI>http://demo_sparql_server2/sparql <Param name="str1" path="?a/rdfs:label" /> </EndpointURI> <Param name="str2" path="?b/gn:name" /> <Graph>http://sws.geonames.org/</Graph> </Compare> </DataSource> <Compare metric="numSimilarity"> <Param name="num1" <Thresholds accept="0.9" verify="0.7" /> path="?a/dbpedia:populationTotal" /> <Output acceptedLinks="accepted_links.n3" <Param name="num2" path="?b/gn:population" /> verifyLinks="verify_links.n3" </Compare> mode="truncate" /> </AVG> </LinkCondition> </Interlink> </Silk>
- 39. Where to findlinks ?
- 40. Towards automated interconnexionservices Ø The linkage specification could be simplified § Using alignments between vocabularies § Detection of discriminating properties § Indicating comparison methods by attaching metadata to ontologies Ø Work in progress in Datalift
- 41. 5th floor -Applications SemWebPro 18/01/2011 41
- 42. Data visualization Tabulator (CSAIL, MIT)
- 43.
- 44.
- 46.
- 47. A few examplesfrom US http://data-gov.tw.rpi.edu/demo/USForeignAid/demo-1554.html
- 48. Mashups … Mashups… Mashups …
- 49. That's it ! ● Datalift.org ● We're looking for a Datageek !