In computing, linked data is structured data which is interlinked with other data so it becomes more useful through semantic queries. It builds upon standard Web technologies such as HTTP, RDF and URIs, but rather than using them to serve web pages only for human readers, it extends them to share information in a way that can be read automatically by computers. Part of the vision of linked data is for the Internet to become a global database.[1]
Wikidata in the Linked Open Data Cloud. Databases indicated as circles (with wikidata indicated as ‘WD’), with grey lines linking databases in the network if their data is aligned.DBpedia as the most interlinked LOD dataset and crystallization point of the Linked Open Data Cloud since 2008, generated from https://lod-cloud.net/
Linked open data are linked data that are open data.[5][6][7] Tim Berners-Lee gives the clearest definition of linked open data in differentiation with linked data.
Linked Open Data (LOD) is Linked Data which is released under an open license, which does not impede its reuse for free.
In 2010, Tim Berners-Lee suggested a 5-star scheme for grading the quality of open data on the web, for which the highest ranking is Linked Open Data:[10]
3 stars: data is available in a non-proprietary structured format, such as Comma-separated values (.csv).
4 stars: data follows W3C standards, like using RDF and employing URIs.
5 stars: all of the others, plus links to other Linked Open Data sources.
History
The term "linked open data" has been in use since at least February 2007, when the "Linking Open Data" mailing list[11] was created.[12] The mailing list was initially hosted by the SIMILE project[13] at the Massachusetts Institute of Technology.
Linking Open Data community project
The above diagram shows which Linking Open Data datasets are connected, as of August 2014. This was produced by the Linked Open Data Cloud project, which was started in 2007. Some sets may include copyrighted data which is freely available.[14]The same diagram as above, but for February 2017, showing the growth in just two and a half years.
The goal of the W3C Semantic Web Education and Outreach group's Linking Open Data community project is to extend the Web with a data commons by publishing various opendatasets as RDF on the Web and by setting RDF links between data items from different data sources. In October 2007, datasets consisted of over two billion RDF triples, which were interlinked by over two million RDF links.[15][16] By September 2011 this had grown to 31 billion RDF triples, interlinked by around 504 million RDF links. A detailed statistical breakdown was published in 2014.[17]
European Union projects
There are a number of European Union projects involving linked data. These include the linked open data around the clock (LATC) project,[18] the AKN4EU project for machine-readable legislative data,[19] the PlanetData project,[20] the DaPaaS (Data-and-Platform-as-a-Service) project,[21] and the Linked Open Data 2 (LOD2) project.[22][23][24] Data linking is one of the main goals of the EU Open Data Portal, which makes available thousands of datasets for anyone to reuse and link.
Ontologies
Ontologies are formal descriptions of data structures. Some of the better known ontologies are:
FOAF – an ontology describing persons, their properties and relationships
UMBEL – a lightweight reference structure of 20,000 subject concept classes and their relationships derived from OpenCyc, which can act as binding classes to external data; also has links to 1.5 million named entities from DBpedia and YAGO
Datasets
DBpedia – a dataset containing extracted data from Wikipedia; it contains about 3.4 million concepts described by 1 billion triples, including abstracts in 11 different languages
GeoNames – provides RDF descriptions of more than 7,500,000 geographical features worldwide
Wikidata – a collaboratively-created linked dataset that acts as central storage for the structured data of its Wikimedia Foundation sibling projects
Global Research Identifier Database (GRID) – an international database of 89,506 institutions engaged in academic research, with 14,401 relationships. GRID models two types of relationships: a parent-child relationship that defines a subordinate association, and a related relationship that describes other associations[25][26]
KnowWhereGraph[27] – an integrated 12 billion triples strong knowledge graph of 30 data layers at the intersection between humans and their environment using Semantic Web and Linked Data technologies.[28]
Clickable diagrams that show the individual datasets and their relationships within the DBpedia-spawned LOD cloud (as by the figures to the right) are available.[29][30]
See also
American Art Collaborative - consortium of US art museums committed to establishing a critical mass of linked open data on American art
^Linking open data cloud diagram 2014, by Max Schmachtenberg, Christian Bizer, Anja Jentzsch and Richard Cyganiak. http://lod-cloud.net/
^"SweoIG/TaskForces/CommunityProjects/LinkingOpenData - W3C Wiki". esw.w3.org. Retrieved 22 March 2018.
^Fensel, Dieter; Facca, Federico Michele; Simperl, Elena; Ioan, Toma (2011). Semantic Web Services. Springer. p. 99. ISBN978-3642191923.
^Max. "State of the LOD Cloud". linkeddatacatalog.dws.informatik.uni-mannheim.de. Retrieved 22 March 2018.
^. latc-project.eu. Archived from the original on 19 September 2018. Retrieved 22 March 2018.
^Flatt, Amelie; Langner, Arne; Leps, Olof (2022), "Model-Driven Development of AKN Application Profiles: Background and Requirements", Model-Driven Development of Akoma Ntoso Application Profiles, Cham: Springer International Publishing, pp. 5–12, doi:10.1007/978-3-031-14132-4_2, ISBN978-3-031-14131-7, retrieved 2023-01-07
^. planet-data.eu. Archived from the original on 21 April 2021. Retrieved 22 March 2018.
^. project.dapaas.eu. Archived from the original on 18 December 2020. Retrieved 22 March 2018.
^Krzysztof Janowicz; Pascal Hitzler; Wenwen Li; Dean Rehberger; Mark Schildhauer; Rui Zhu; Cogan Shimizu; Colby K. Fisher; Ling Cai; Gengchen Mai; Joseph Zalewski; Lu Zhou; Shirly Stephen; Seila Gonzalez Estrecha; Bryce D. Mecum; Anna Lopez-Carr; Andrew Schroeder; Dave Smith; Dawn J. Wright; Sizhe Wang; Yuanyuan Tian; Zilong Liu; Meilin Shi; Anthony D'Onofrio; Zhining G; Kitty Currier (2022). "Know, Know Where, Knowwheregraph: A Densely Connected, Cross-Domain Knowledge Graph and Geo-Enrichment Service Stack for Applications in Environmental Intelligence". AI Magazine. 43 (1): 30–39. doi:10.1609/aimag.v43i1.19120.
^. fu-berlin.de. Archived from the original on 2012-10-17. Retrieved 22 March 2018.
^. Archived from the original on 28 August 2011. Retrieved 22 March 2018.
Further reading
Ahmet Soylu, Felix Mödritscher, and Patrick De Causmaecker. 2012. "Ubiquitous Web Navigation through Harvesting Embedded Semantic Data: A Mobile Scenario." 2018-09-19 at the Wayback Machine Integrated Computer-Aided Engineering 19 (1): 93–109.
Linked Data: Evolving the Web into a Global Data Space (2011) by Tom Heath and Christian Bizer, Synthesis Lectures on the Semantic Web: Theory and Technology, Morgan & Claypool
How to Publish Linked Data on the Web 2021-04-19 at the Wayback Machine, by Chris Bizer, Richard Cyganiak and Tom Heath, Linked Data Tutorial at Freie Universität Berlin, Germany, 27 July 2007.
The Web Turns 20: Linked Data Gives People Power, part 1 of 4, by Mark Fischetti, Scientific American 2010 October 23
– Prateek Jain, Pascal Hitzler, Peter Z. Yeh, Kunal Verma, and Amit P. Sheth. In: Dan Brickley, Vinay K. Chaudhri, Harry Halpin, and Deborah McGuinness: Linked Data Meets Artificial Intelligence. Technical Report SS-10-07, AAAI Press, Menlo Park, California, 2010, pp. 82–86.
– Prateek Jain, Pascal Hitzler, Kunal Verma, Peter Z. Yeh, Amit Sheth. In: Proceedings of the 23rd ACM Hypertext and Social Media conference (HT 2012), Milwaukee, WI, USA, June 25–28, 2012.
Freitas, André, Edward Curry, João Gabriel Oliveira, and Sean O’Riain. 2012. "Querying Heterogeneous Datasets on the Linked Data Web: Challenges, Approaches, and Trends." IEEE Internet Computing 16 (1): 24–33.
– Chris Bizer, Tom Heath, Danny Ayers, Yves Raimond. In Proceedings Poster Track, ESWC2007, Innsbruck, Austria
– Prateek Jain, Pascal Hitzler, Amit Sheth, Kunal Verma, Peter Z. Yeh. In proceedings of the 9th International Semantic Web Conference, ISWC 2010, Shanghai, China
Linked open drug data for pharmaceutical research and development - J Cheminform. 2011; 3: 19. Samwald, Jentzsch, Bouton, Kallesøe, Willighagen, Hajagos, Marshall, Prud'hommeaux, Hassenzadeh, Pichler, and Stephens (May 2011)
Interview with Sören Auer, head of the LOD2 project about the continuation of LOD2 in 2011, June 2011
Linked Open Data: The Essentials - Florian Bauer and Martin Kaltenböck (January 2012)
linked, data, computing, linked, data, structured, data, which, interlinked, with, other, data, becomes, more, useful, through, semantic, queries, builds, upon, standard, technologies, such, http, uris, rather, than, using, them, serve, pages, only, human, rea. In computing linked data is structured data which is interlinked with other data so it becomes more useful through semantic queries It builds upon standard Web technologies such as HTTP RDF and URIs but rather than using them to serve web pages only for human readers it extends them to share information in a way that can be read automatically by computers Part of the vision of linked data is for the Internet to become a global database 1 Wikidata in the Linked Open Data Cloud Databases indicated as circles with wikidata indicated as WD with grey lines linking databases in the network if their data is aligned DBpedia as the most interlinked LOD dataset and crystallization point of the Linked Open Data Cloud since 2008 generated from https lod cloud net Tim Berners Lee director of the World Wide Web Consortium W3C coined the term in a 2006 design note about the Semantic Web project 2 Linked data may also be open data in which case it is usually described as Linked Open Data 3 Contents 1 Principles 2 Components 3 Linked open data 3 1 5 star linked open data 3 2 History 3 3 Linking Open Data community project 3 4 European Union projects 3 5 Ontologies 3 6 Datasets 3 7 Dataset instance and class relationships 4 See also 5 References 6 Further reading 7 External linksPrinciples EditIn his 2006 Linked Data note Tim Berners Lee outlined four principles of linked data paraphrased along the following lines 2 Uniform Resource Identifiers URIs should be used to name and identify individual things HTTP URIs should be used to allow these things to be looked up interpreted and subsequently dereferenced Useful information about what a name identifies should be provided through open standards such as RDF SPARQL etc When publishing data on the Web other things should be referred to using their HTTP URI based names Tim Berners Lee later restated these principles at a 2009 TED conference again paraphrased along the following lines 4 All conceptual things should have a name starting with HTTP Looking up an HTTP name should return useful data about the thing in question in a standard format Anything else that that same thing has a relationship with through its data should also be given a name beginning with HTTP Components EditURIs HTTP Structured data using controlled vocabulary terms and dataset definitions expressed in Resource Description Framework serialization formats such as RDFa RDF XML N3 Turtle or JSON LD Linked Data PlatformLinked open data EditLinked open data are linked data that are open data 5 6 7 Tim Berners Lee gives the clearest definition of linked open data in differentiation with linked data Linked Open Data LOD is Linked Data which is released under an open license which does not impede its reuse for free Tim Berners Lee Linked Data 2 8 Large linked open data sets include DBpedia Wikibase Wikidata and Open Icecat 5 star linked open data Edit Deployment scheme for Linked Open Data 9 In 2010 Tim Berners Lee suggested a 5 star scheme for grading the quality of open data on the web for which the highest ranking is Linked Open Data 10 1 star data is openly available in some format 2 stars data is available in a structured format such as Microsoft Excel file format xls 3 stars data is available in a non proprietary structured format such as Comma separated values csv 4 stars data follows W3C standards like using RDF and employing URIs 5 stars all of the others plus links to other Linked Open Data sources History Edit The term linked open data has been in use since at least February 2007 when the Linking Open Data mailing list 11 was created 12 The mailing list was initially hosted by the SIMILE project 13 at the Massachusetts Institute of Technology Linking Open Data community project Edit The above diagram shows which Linking Open Data datasets are connected as of August 2014 This was produced by the Linked Open Data Cloud project which was started in 2007 Some sets may include copyrighted data which is freely available 14 The same diagram as above but for February 2017 showing the growth in just two and a half years The goal of the W3C Semantic Web Education and Outreach group s Linking Open Data community project is to extend the Web with a data commons by publishing various open datasets as RDF on the Web and by setting RDF links between data items from different data sources In October 2007 datasets consisted of over two billion RDF triples which were interlinked by over two million RDF links 15 16 By September 2011 this had grown to 31 billion RDF triples interlinked by around 504 million RDF links A detailed statistical breakdown was published in 2014 17 European Union projects Edit There are a number of European Union projects involving linked data These include the linked open data around the clock LATC project 18 the AKN4EU project for machine readable legislative data 19 the PlanetData project 20 the DaPaaS Data and Platform as a Service project 21 and the Linked Open Data 2 LOD2 project 22 23 24 Data linking is one of the main goals of the EU Open Data Portal which makes available thousands of datasets for anyone to reuse and link Ontologies Edit Ontologies are formal descriptions of data structures Some of the better known ontologies are FOAF an ontology describing persons their properties and relationships UMBEL a lightweight reference structure of 20 000 subject concept classes and their relationships derived from OpenCyc which can act as binding classes to external data also has links to 1 5 million named entities from DBpedia and YAGODatasets Edit DBpedia a dataset containing extracted data from Wikipedia it contains about 3 4 million concepts described by 1 billion triples including abstracts in 11 different languages GeoNames provides RDF descriptions of more than 7 500 000 geographical features worldwide Wikidata a collaboratively created linked dataset that acts as central storage for the structured data of its Wikimedia Foundation sibling projects Global Research Identifier Database GRID an international database of 89 506 institutions engaged in academic research with 14 401 relationships GRID models two types of relationships a parent child relationship that defines a subordinate association and a related relationship that describes other associations 25 26 KnowWhereGraph 27 an integrated 12 billion triples strong knowledge graph of 30 data layers at the intersection between humans and their environment using Semantic Web and Linked Data technologies 28 Open Icecat a multilingual open catalogue containing product datasheets related digital assets and usage statistics Dataset instance and class relationships Edit Clickable diagrams that show the individual datasets and their relationships within the DBpedia spawned LOD cloud as by the figures to the right are available 29 30 See also EditAmerican Art Collaborative consortium of US art museums committed to establishing a critical mass of linked open data on American art Authority control about controlled headings in library catalogs Citation analysis for citations between scholarly articles Hyperdata Network model an older type of database management system Open data Schema org VoID Vocabulary of Interlinked Datasets Web Ontology Language List of datasets for machine learning researchReferences Edit Linked Data as JSON Linked Data as JSON Retrieved 2020 12 04 a b c Tim Berners Lee 2006 07 27 Linked Data Design Issues W3C Retrieved 2010 12 18 What are Linked Data and Linked Open Data Ontotext Retrieved 2019 05 08 Tim Berners Lee on the next Web Archived from the original on 2011 04 10 Retrieved 2009 03 15 Frequently Asked Questions FAQs Linked Data Connect Distributed Data across the Web Archived from the original on 2015 11 18 Retrieved 2014 12 29 COAR 7 things you should know about Linked Data Archived from the original on 2015 11 18 Retrieved 2015 12 29 Linked Data Basics for Techies Archived from the original on 2021 05 05 Retrieved 2015 12 29 5 Star Open Data 5 star Open Data 5stardata info Retrieved 2021 03 07 What is 5 Star Linked Data Webize Everything Community Group www w3 org Retrieved 2021 03 07 public lod w3 org Mail Archives SweoIG TaskForces CommunityProjects LinkingOpenData NewsArchive SIMILE Project Mailing Lists Linking open data cloud diagram 2014 by Max Schmachtenberg Christian Bizer Anja Jentzsch and Richard Cyganiak http lod cloud net SweoIG TaskForces CommunityProjects LinkingOpenData W3C Wiki esw w3 org Retrieved 22 March 2018 Fensel Dieter Facca Federico Michele Simperl Elena Ioan Toma 2011 Semantic Web Services Springer p 99 ISBN 978 3642191923 Max State of the LOD Cloud linkeddatacatalog dws informatik uni mannheim de Retrieved 22 March 2018 Linked open data around the clock LATC latc project eu Archived from the original on 19 September 2018 Retrieved 22 March 2018 Flatt Amelie Langner Arne Leps Olof 2022 Model Driven Development of AKN Application Profiles Background and Requirements Model Driven Development of Akoma Ntoso Application Profiles Cham Springer International Publishing pp 5 12 doi 10 1007 978 3 031 14132 4 2 ISBN 978 3 031 14131 7 retrieved 2023 01 07 Welcome to PlanetData PlanetData planet data eu Archived from the original on 21 April 2021 Retrieved 22 March 2018 DaPaaS project dapaas eu Archived from the original on 18 December 2020 Retrieved 22 March 2018 Linking Open Data 2 LOD2 CORDIS FP7 ICT Projects LOD2 European Commission 2010 04 20 LOD2 Project Fact Sheet Project Summary PDF 2010 09 01 Archived from the original PDF on 2011 07 20 Retrieved 2010 12 18 GRID Statistics grid ac stats Retrieved 2018 10 26 GRID Policies grid ac Retrieved 2018 10 26 KnowWhereGraph knowwheregraph org Retrieved 2022 05 16 Krzysztof Janowicz Pascal Hitzler Wenwen Li Dean Rehberger Mark Schildhauer Rui Zhu Cogan Shimizu Colby K Fisher Ling Cai Gengchen Mai Joseph Zalewski Lu Zhou Shirly Stephen Seila Gonzalez Estrecha Bryce D Mecum Anna Lopez Carr Andrew Schroeder Dave Smith Dawn J Wright Sizhe Wang Yuanyuan Tian Zilong Liu Meilin Shi Anthony D Onofrio Zhining G Kitty Currier 2022 Know Know Where Knowwheregraph A Densely Connected Cross Domain Knowledge Graph and Geo Enrichment Service Stack for Applications in Environmental Intelligence AI Magazine 43 1 30 39 doi 10 1609 aimag v43i1 19120 Instance relationships amongst datasets fu berlin de Archived from the original on 2012 10 17 Retrieved 22 March 2018 Class relationships amongst datasets Archived from the original on 28 August 2011 Retrieved 22 March 2018 Further reading EditAhmet Soylu Felix Modritscher and Patrick De Causmaecker 2012 Ubiquitous Web Navigation through Harvesting Embedded Semantic Data A Mobile Scenario Archived 2018 09 19 at the Wayback Machine Integrated Computer Aided Engineering 19 1 93 109 Linked Data Evolving the Web into a Global Data Space 2011 by Tom Heath and Christian Bizer Synthesis Lectures on the Semantic Web Theory and Technology Morgan amp Claypool How to Publish Linked Data on the Web Archived 2021 04 19 at the Wayback Machine by Chris Bizer Richard Cyganiak and Tom Heath Linked Data Tutorial at Freie Universitat Berlin Germany 27 July 2007 The Web Turns 20 Linked Data Gives People Power part 1 of 4 by Mark Fischetti Scientific American 2010 October 23 Linked Data Is Merely More Data Prateek Jain Pascal Hitzler Peter Z Yeh Kunal Verma and Amit P Sheth In Dan Brickley Vinay K Chaudhri Harry Halpin and Deborah McGuinness Linked Data Meets Artificial Intelligence Technical Report SS 10 07 AAAI Press Menlo Park California 2010 pp 82 86 Moving beyond sameAs with PLATO Partonomy detection for Linked Data Prateek Jain Pascal Hitzler Kunal Verma Peter Z Yeh Amit Sheth In Proceedings of the 23rd ACM Hypertext and Social Media conference HT 2012 Milwaukee WI USA June 25 28 2012 Freitas Andre Edward Curry Joao Gabriel Oliveira and Sean O Riain 2012 Querying Heterogeneous Datasets on the Linked Data Web Challenges Approaches and Trends IEEE Internet Computing 16 1 24 33 Interlinking Open Data on the Web Chris Bizer Tom Heath Danny Ayers Yves Raimond In Proceedings Poster Track ESWC2007 Innsbruck Austria Ontology Alignment for Linked Open Data Prateek Jain Pascal Hitzler Amit Sheth Kunal Verma Peter Z Yeh In proceedings of the 9th International Semantic Web Conference ISWC 2010 Shanghai China Linked open drug data for pharmaceutical research and development J Cheminform 2011 3 19 Samwald Jentzsch Bouton Kallesoe Willighagen Hajagos Marshall Prud hommeaux Hassenzadeh Pichler and Stephens May 2011 Interview with Soren Auer head of the LOD2 project about the continuation of LOD2 in 2011 June 2011 Linked Open Data The Essentials Florian Bauer and Martin Kaltenbock January 2012 The Flap of a Butterfly Wing semanticweb com Richard Wallis February 2012 External links Edit Scholia has a topic profile for Linked data LinkedData at the W3C Wiki LinkedData org OpenLink Software white papers Retrieved from https en wikipedia org w index php title Linked data amp oldid 1162429734 Linked open data, wikipedia, wiki, book, books, library,
