Dữ liệu liên kết

Tập tin:Linked-open-data-Europeana-video.ogv

Tổng quan về dữ liệu liên kết mở trong bối cảnh của các tổ chức văn hóa.

Trong hoạt động tính toán máy tính, Dữ liệu Liên kết mô tả một phương thức tạo ra dữ liệu có cấu trúc để có thể liên kết được với nhau và trở nên có ích. Dữ liệu liên kết được xây dựng dựa trên các tiêu chuẩn công nghệ Web như HTTP và URI để mở rộng khả năng chia sẻ thông tin theo cách có thể được đọc tự động từ các máy tính hơn là việc chia sẻ nội dung trên các trang web để phục vụ cho người dùng. Điều này cho phép các nguồn tài nguyên khác nhau được kết nối và truy vấn.

Ông Tim Berners-Lee, cha đẻ của World Wide Web Consortium, đặt ra thuật ngữ trong thảo luận lưu ý thiết kế xoay quanh dự án Semantic Web.

Principles

Tim Berners-Lee liệt kê 4 nguyên lý dữ liệu liên kết trong vấn đề thảo luận của mình: Ghi chú Dữ liệu Liên kết, paraphrased along the following lines:

1. Dùng URI để nhận dạng mọi thứ.
2. Sử dụng HTTP URI các thứ này được tham khảo và tìm kiếm ("dereferenced") bởi mọi người hay user agents.
3. Provide useful information about the thing when its URI is dereferenced, using standard formats such as RDF/XML.
4. Include links to other, related URIs in the exposed data to improve discovery of other related information on the Web.

Tim Berners-Lee gave a presentation on linked data at the TED 2009 conference. In it, he restated the linked data principles as three "extremely simple" rules:

1. All kinds of conceptual things, they have names now that start with HTTP.
2. I get important information back. I will get back some data in a standard format which is kind of useful data that somebody might like to know about that thing, about that event.
3. I get back that information it's not just got somebody's height and weight and when they were born, it's got relationships. And when it has relationships, whenever it expresses a relationship then the other thing that it's related to is given one of those names that starts with HTTP.

Note that although the second rule mentions "standard formats", it does not require any specific standard, such as RDF/XML.

Components

• URIs (specifically, of the dereferenceable variety)
• HTTP
• Resource Description Framework (RDF)
• Serialization formats (RDFa, RDF/XML, N3, Turtle, and others)

Linking open-data community project

Instance linkages within the linking open data datasets

Tập tin:Linking-Open-Data-class-diagram 2008-10-05.png

Class linkages within the linking open data datasets

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. By September 2011 this had grown to 31 billion RDF triples, interlinked by around 504 million RDF links. There is also an interactive visualization of the linked data sets to browse through the cloud.

EU Projects

There a number of EU projects involving linked data. These include the linked open data around the clock (LATC) project, the PlanetData project, and the Linked Open Data 2 (LOD2) project.

Datasets

• CKAN – registry of open data and content packages provided by the Open Knowledge Foundation
• 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.
• 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
• FOAF – a dataset describing persons, their properties and relationships

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:

• Instance relationships amongst datasets [1]
• Class relationships amongst datasets [2]

See also

• Dữ liệu mở
• Wikidata
• Dự án Callimachus

Nghiên cứu thêm

• 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
• 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, 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.
• Linked Data on the Web – Chris Bizer, Tom Heath, Kingsley Uyi Idehen, Tim Berners-Lee. In Proceedings WWW2008, Beijing, China
• 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, 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)

Liên kết ngoài

• LinkedData at the W3C Wiki
• LinkedData.org
• OpenLink Software white papers

Các trường hợp thử nghiệm

• Data from Northwind SQL schema as linked data
• Linked data for the discipline of numismatics