N3,
Turtle
Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...
, or
JSON-LD
JSON-LD (JavaScript Object Notation for Linked Data) is a method of encoding linked data using JSON. One goal for JSON-LD was to require as little effort as possible from developers to transform their existing JSON to JSON-LD. JSON-LD allows data ...
*
Linked Data Platform Linked Data Platform (LDP) is a linked data specification defining a set of integration patterns for building RESTful HTTP services that are capable of read/write of RDF data.
The Linked Data Platform allows use of RESTful HTTP to consume, create ...
Linked open data
Linked open data are linked data that are
open data
Open data is data that is openly accessible, exploitable, editable and shared by anyone for any purpose. Open data is licensed under an open license.
The goals of the open data movement are similar to those of other "open(-source)" movements ...
. Tim Berners-Lee gives the clearest definition of linked open data in differentiation with linked data.
Large linked open data sets include
DBpedia
DBpedia (from "DB" for " database") is a project aiming to extract structured content from the information created in the Wikipedia project. This structured information is made available on the World Wide Web. DBpedia allows users to semanti ...
,
Wikibase
Wikibase is a set of MediaWiki extensions for working with versioned semi-structured data in a central repository based upon JSON instead of the unstructured data of MediaWiki wikitext. Its primary components are the ''Wikibase Repository'', an ...
,
Wikidata
Wikidata is a collaboratively edited multilingual knowledge graph hosted by the Wikimedia Foundation. It is a common source of open data that Wikimedia projects such as Wikipedia, and anyone else, can use under the CC0 public domain license ...
and
Open Icecat
Open or OPEN may refer to:
Music
* Open (band), Australian pop/rock band
* The Open (band), English indie rock band
* ''Open'' (Blues Image album), 1969
* ''Open'' (Gotthard album), 1999
* ''Open'' (Cowboy Junkies album), 2001
* ''Open'' ( ...
.
5-star linked open data
Tim Berners-Lee
Sir Timothy John Berners-Lee (born 8 June 1955), also known as TimBL, is an English computer scientist best known as the inventor of the World Wide Web. He is a Professorial Fellow of Computer Science at the University of Oxford and a profess ...
has suggested a 5-star scheme for grading the quality of open data on the web, for which the highest ranking is Linked Open Data:
* 1 star: data is openly available in some format.
* 2 stars: data is available in a structured format, such as
Microsoft Excel file format
Microsoft Excel is a spreadsheet developed by Microsoft for Windows, macOS, Android and iOS. It features calculation or computation capabilities, graphing tools, pivot tables, and a macro programming language called Visual Basic for Appl ...
(.xls).
* 3 stars: data is available in a non-proprietary structured format, such as
Comma-separated values
A comma-separated values (CSV) file is a delimited text file that uses a comma to separate values. Each line of the file is a data record. Each record consists of one or more fields, separated by commas. The use of the comma as a field separat ...
(.csv).
* 4 stars: data follows
W3C
The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web. Founded in 1994 and led by Tim Berners-Lee, the consortium is made up of member organizations that maintain full-time staff working to ...
standards, like using
RDF and employing
URIs.
* 5 stars: all of the other, 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 was created. The mailing list was initially hosted by the
SIMILE
A simile () is a figure of speech that directly ''compares'' two things. Similes differ from other metaphors by highlighting the similarities between two things using comparison words such as "like", "as", "so", or "than", while other metaphors cr ...
project at the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
.
Linking Open Data community project
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
Open or OPEN may refer to:
Music
* Open (band), Australian pop/rock band
* The Open (band), English indie rock band
* ''Open'' (Blues Image album), 1969
* ''Open'' (Gotthard album), 1999
* ''Open'' (Cowboy Junkies album), 2001
* ''Open'' (YF ...
dataset A data set (or dataset) is a collection of data. In the case of tabular data, a data set corresponds to one or more database tables, where every column of a table represents a particular variable, and each row corresponds to a given record of the ...
s 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. 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.
European Union projects
There are a number of
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
projects involving linked data. These include the linked open data around the clock (LATC) project, the PlanetData project, the DaPaaS (Data-and-Platform-as-a-Service) project, and the Linked Open Data 2 (LOD2) project. Data linking is one of the main goals of the
EU Open Data Portal
Before data.europa.eu, the EU Open Data Portal was the point of access to public data published by the EU institutions, agencies and other bodies. On April 21, 2021 it was consolidated to the data.europa.eu portal, together with the European Data ...
, which makes available thousands of datasets for anyone to reuse and link.
Ontologies
Ontologies
In computer science and information science, an ontology encompasses a representation, formal naming, and definition of the categories, properties, and relations between the concepts, data, and entities that substantiate one, many, or all domains ...
are formal descriptions of data structures. Some of the better known ontologies are:
*
FOAF
FOAF (an acronym of friend of a friend) is a machine-readable ontology describing persons, their activities and their relations to other people and objects. Anyone can use FOAF to describe themselves. FOAF allows groups of people to describe soc ...
– an ontology describing persons, their properties and relationships
*
UMBEL
In botany, an umbel is an inflorescence that consists of a number of short flower stalks (called pedicels) that spread from a common point, somewhat like umbrella ribs. The word was coined in botanical usage in the 1590s, from Latin ''umbella'' "p ...
– a lightweight reference structure of subject concept classes and their relationships derived from
OpenCyc
Cyc (pronounced ) is a long-term artificial intelligence project that aims to assemble a comprehensive ontology and knowledge base that spans the basic concepts and rules about how the world works. Hoping to capture common sense knowledge, Cyc f ...
, which can act as binding classes to external data; also has links to 1.5 million named entities from DBpedia and
YAGO
Datasets
*
DBpedia
DBpedia (from "DB" for " database") is a project aiming to extract structured content from the information created in the Wikipedia project. This structured information is made available on the World Wide Web. DBpedia allows users to semanti ...
– 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
GeoNames (or GeoNames.org) is a user editable geographical database available and accessible through various web services, under a Creative Commons attribution license. The project was founded in late 2005.
The GeoNames dataset differs from ...
– provides RDF descriptions of more than geographical features worldwide
*
Wikidata
Wikidata is a collaboratively edited multilingual knowledge graph hosted by the Wikimedia Foundation. It is a common source of open data that Wikimedia projects such as Wikipedia, and anyone else, can use under the CC0 public domain license ...
– a collaboratively-created linked dataset that acts as central storage for the structured data of its
Wikimedia Foundation
The Wikimedia Foundation, Inc., or Wikimedia for short and abbreviated as WMF, is an American 501(c)(3) nonprofit organization headquartered in San Francisco, California and registered as a charitable foundation under local laws. Best kno ...
sibling projects
*
Global Research Identifier Database (''GRID'') – an international database of institutions engaged in academic research, with relationships. GRID models two types of relationships: a parent-child relationship that defines a subordinate association, and a related relationship that describes other associations
* KnowWhereGraph
– an integrated 12 billion triples strong
knowledge graph
The Google Knowledge Graph is a knowledge base from which Google serves relevant information in an infobox beside its search results. This allows the user to see the answer in a glance. The data is generated automatically from a variety of sou ...
of 30 data layers at the intersection between humans and their environment using Semantic Web and Linked Data technologies.
*
Open Icecat
Open or OPEN may refer to:
Music
* Open (band), Australian pop/rock band
* The Open (band), English indie rock band
* ''Open'' (Blues Image album), 1969
* ''Open'' (Gotthard album), 1999
* ''Open'' (Cowboy Junkies album), 2001
* ''Open'' ( ...
- a
multilingual
Multilingualism is the use of more than one language, either by an individual speaker or by a group of speakers. It is believed that multilingual speakers outnumber monolingual speakers in the world's population. More than half of all E ...
open catalogue Open catalogue is an open content catalogue or free content catalogue, a structured database with information about products or other stored items in a standardized format. A catalogue implies categorization or classification of the items involved ...
containing product
datasheets
A datasheet, data sheet, or spec sheet is a document that summarizes the performance and other characteristics of a product, machine, component (e.g., an electronic component), material, subsystem (e.g., a power supply), or software in suffici ...
, related
digital assets
A digital asset is anything that exists only in digital form and comes with a distinct usage right. Data that do not possess that right are not considered assets.
''Digital assets'' include but are not exclusive to: digital documents, audible ...
and usage
statistics
Statistics (from German language, German: ''wikt:Statistik#German, Statistik'', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of ...
.
Dataset instance and class relationships
Clickable diagrams that show the individual datasets and their relationships within the DBpedia-spawned LOD cloud (as shown by the figures to the right) are available.
See also
*
American Art Collaborative
The American Art Collaborative (AAC) is a consortium of 14 art museums in the United States, whose mission is the establishment of "a critical mass of linked open data (LOD) on the semantic web."
Membership
As of 2018, the 14 members were:
* Amo ...
- consortium of US art museums committed to establishing a critical mass of linked open data on American art
*
Authority control
In information science, authority control is a process that organizes information, for example in library catalogs, by using a single, distinct spelling of a name (heading) or a numeric identifier for each topic. The word ''authority'' in ''au ...
– about ''controlled headings'' in library catalogs
*
Citation analysis
Citation analysis is the examination of the frequency, patterns, and graphs of citations in documents. It uses the directed graph of citations — links from one document to another document — to reveal properties of the documents. A t ...
– for citations between scholarly articles
*
Hyperdata
Hyperdata are data objects linked to other data objects in other places, as hypertext indicates text linked to other text in other places. Hyperdata enables formation of a web of data, evolving from the "data on the Web" that is not inter-related ...
*
Network model
The network model is a database model conceived as a flexible way of representing objects and their relationships. Its distinguishing feature is that the schema, viewed as a graph in which object types are nodes and relationship types are arcs, ...
– an older type of database management system
*
Open data
Open data is data that is openly accessible, exploitable, editable and shared by anyone for any purpose. Open data is licensed under an open license.
The goals of the open data movement are similar to those of other "open(-source)" movements ...
*
Schema.org
Schema.org is a reference website that publishes documentation and guidelines for using structured data mark-up on web-pages (called microdata). Its main objective is to standardize HTML tags to be used by webmasters for creating rich results (di ...
*
VoID
Void may refer to:
Science, engineering, and technology
* Void (astronomy), the spaces between galaxy filaments that contain no galaxies
* Void (composites), a pore that remains unoccupied in a composite material
* Void, synonym for vacuum, a ...
– Vocabulary of Interlinked Datasets
*
Web Ontology Language
The Web Ontology Language (OWL) is a family of knowledge representation languages for authoring ontologies. Ontologies are a formal way to describe taxonomies and classification networks, essentially defining the structure of knowledge for variou ...
References
Further reading
* Ahmet Soylu, Felix Mödritscher, and Patrick De Causmaecker. 2012
“Ubiquitous Web Navigation through Harvesting Embedded Semantic Data: A Mobile Scenario.”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 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
''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...
'' 2010 October 23
Linked Data Is Merely More Data– Prateek Jain,
Pascal Hitzler
Pascal Hitzler is a German American computer scientist specializing in Semantic Web and Artificial Intelligence. He is endowed Lloyd T. Smith Creativity in Engineering Chair and Director of the Center for Artificial Intelligence and Data Science ...
, 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
Pascal Hitzler is a German American computer scientist specializing in Semantic Web and Artificial Intelligence. He is endowed Lloyd T. Smith Creativity in Engineering Chair and Director of the Center for Artificial Intelligence and Data Science ...
, 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.
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
Pascal Hitzler is a German American computer scientist specializing in Semantic Web and Artificial Intelligence. He is endowed Lloyd T. Smith Creativity in Engineering Chair and Director of the Center for Artificial Intelligence and Data Science ...
, 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)
The Flap of a Butterfly Wing- semanticweb.com Richard Wallis (February 2012)
External links
LinkedDataat the W3C Wiki
LinkedData.orgOpenLink Software white papers
{{Authority control
Computer-related introductions in 2007
Cloud standards
Data management
Distributed computing architecture
Hypermedia
Internet terminology
Open data
Semantic Web