Linked Open Data Project

M.S.F.Fayaza

114039T

Faculty of Information technology

University of Moratuwa

Outline

• Why we need Semantic web?• Linked Open Data• Open Data • Linked Data

• How does it work?• The important of Linked Open Data• Disadvantages of Linked Open Data• Accessing Linked Open Data Sets• Publishing Linked Open Data• Consuming Linked Open Data

Why we need Semantic web?

• The World Wide Web facilitates the global information spaceby comprising the linked documents.

• The current web is mainly concern the presentation of data.They are links the HTML pages or documents. But machineshave no way to understand these documents and cannotmake any intelligent decision about these documents.

• We need to help machines to understand the web somachines can help us understand things

• They can learn what we are interested in

• They can help us better find what we want

Why we need Semantic web?

• So need to publish something that computers can understand.

• The semantic web isn‘t just about putting data on the web . Itis about making links, so that a person or machine can explorethe semantically connected web of data.

• Semantic web goes beyond the concept of document and linksstructured data. With Linked Open Data, can find morerelated data than traditional web.

• Nowadays World Wide Web moving from the a Web of hyper-linked Documents to opening up and interlinking data.

Linked Open Data

• What is Linked Open Data?

• Open Data + Linked Data = Linked Open Data

Linked Open Data

•What is Open Data?

•What is Linked Data ?

Open Data

• Open data is the data that should be freely available toeveryone to use and republish as they wish, withoutrestrictions from copyright, patents or other mechanismsof control

• Data must also be available in a convenient andmodifiable form

• Everyone must be able to use,reuse and redistribute

Open Data Examples

• Open Government and Open (Government) Data

Linked Data

• “A method of publishing structured data so that it can beinterlinked and become more useful.

• It builds upon standard Web technologies such as HTTP,RDF and URIs, but rather than using them to serve webpages for human readers, it extends them to shareinformal on in a way that can be read atomically bycomputers.

• This enables data from different sources to be connectedand queried”

• [Bizer, Heath, Berners--‐Lee 2009]

Linked Data

• The Semantic Web isn't just about putting data on the web. Itis about making links, so that a person or machine can explorethe web of data.

• With linked data, when we have some of it, you can find other,related data.

• Linked Data builds directly on Web architecture and appliesthis architecture to the task of sharing data on global scale.

• Tim Berners-Lee’s introduced four principles on Linked Dataas best practices for publishing and interlinking structureddata on the Web.

Linked Data Principles

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, using the standards (RDF*, SPARQL)

4. Include links to other URIs so that they can discover

more things

Use URIs as names for things

• The Web is an information space in which the items ofinterest, referred to as resources, are identified by globalidentifiers called Uniform Resource Identifiers (URI).

• Use URIs references to identify, not just Web documents anddigital content, but also real world objects and abstractconcepts.

• To publish data on the Web, the items in a domain of interestmust first be identified. These are the things whose propertiesand relationships will be described in the data, and mayinclude Web documents as well as real-world entities andabstract concepts.

• If it doesn't use the universal URI set of symbols, we don't callit Semantic Web.

Use URIs as names for things

URIs are used to identify people and the relationships between them.

HTTP URIs

• The HTTP protocol is the Web’s universal access mechanism

• Use HTTP URIs to identify objects and abstract concepts, enablingthese URIs to be dereferenced over the HTTP protocol into adescription of the identified object or concept.

• HTTP URIs make good names for two reasons:• They provide a simple way to create globally unique names in a decentralized

fashion, as every owner of a domain name, or delegate of the domain name owner, may create new URI references.

• They serve not just as a name but also as a means of accessing information describing the identified entity.

• It’s all about interoperability

• The RDF data model uses URIs only as logical names.

Return information using the standards

• When someone looks up a URI, provide useful information, using thestandards (RDF*, SPARQL)

• In order to enable a wide range of different applications to processWeb content, it is important to agree on standardized contentformats.

• use of a single data model for publishing structured data on the Web– the Resource Description Framework (RDF), a simple graph-baseddata model that has been designed for use in the context of the Web

• As the resulting Web of Data is based on standards and a commondata model, it becomes possible to implement generic applicationsthat operate over the complete data space

links to other URIs

• Include links to other URIs so that they can discover more things

• When applications can follow these links, they can find interesting new things

• This links are expressed through a triple whose subject and objectlive in different datasets.

• Links across the boundaries of datasets support the reuse, the integration and the discovery of data

• Hyperlinks in the Linked Data context are called RDF links in order to distinguish them from hyperlinks between classic Web documents.

Linked Open Data

ALL DATA

Linked Open Data

Linked Data

OpenData

Linked Open Data

• Linked open data is linked data that is open content.

• Open Data refers to data freely available without anyrestrictions. Linked Data refers to semantically linkedmachine-readable data.

• Therefore data can be open but not linked or linked butnot open, however if data is open and linked it thenbecomes Linked Open Data.

• The example for large Linked Open Data is DBpedia.

Linked Open Data project

• Linked Open Data facilitates innovation and knowledge creationfrom interlinked data, it is an important mechanism for informationmanagement and integration.

• To fully benefit from Open Data, it is crucial to put information anddata into a context that creates new knowledge and enablespowerful services and applications.

• The goal of the W3C SWEO Linking Open Data community project isto extend the Web with a data commons by publishing various opendata sets as RDF on the Web and by setting RDF links between dataitems from different data sources.

• Linked Open Data makes the web appear as one giant huge globaldatabase

Linked Open Data

5-star rating scheme

• ★ - Data available on the web in any format, even using PDF or image scan, but with an Open license.

• ★★ - Data delivered as machine-readable structured data

• ★★★-Data available in a non-proprietary format

• ★★★★ - All the above plus, data using open standards from W3C, e.g. RDF and SPARQL, to identify things and properties, so that people can point at other data

• ★★★★★- All the above, plus, to link data to other people’s data to provide context

How does it work?

• Use Resource Description Framework (RDF) to linked dataacross web.

• Resource Description Framework (RDF) enables meaning ofconnection between the items distributed across the web.

• RDF is based on the idea of declaring resources using theexpression in the form subject-predicate-object. This form isknown as RDF triple.

• To create Linked Open Data it is necessary to create automaticlinks between RDF triple stores on the web

Importance of Linked Open Data

• If all the data on the Web were open and linked, it would be easier to establish information systems combining different distributed data repositories

• Linked Open Data enable access and sharing of data and knowledge without barriers.

Disadvantages of Linked Open Data

• Usages of Linked Data increases therefore some the dataavailable might be either irregularly updated, or alreadyavailable in other formats and APIs might become an issue

• Lack of applications and tools to exploit Linked Data.

• Existing open issues make the development of Linked Databased applications a challenge, due to the difficulties tointegrate data in different formats and from multiple sources,the discovery of data or the usability of user interfaces.

Publishing Linked Open Data

• Publishing Linked Open Data provides a powerful mechanism for sharing your own data and information along with your metadata and the respective data models for efficient re-use.

• The essential steps to publishing your own LOD are:

• Identify & analyze your data

• Clean the data

• Model your data (URI schema, vocabularies)

• Select & specify license(s)

• Convert data to RDF

• Link your data to other data

• Publish and promote your Linked Open Data

Publishing LOD

• Official UK Legislation: http://www.legislation.gov.uk

Consuming Linked Open Data

• Consuming LOD enables you to integrate and provide high quality information and data collections to mix your own data and third party information.

• Organizations can benefit and reach competitive advantage through the possibility to:

• spontaneously generate dossiers and information mash ups from distributed information sources;

• create applications based on real time data with less replication;

• create new knowledge out of this interlinked data.

Consuming Linked Open Data

• most important issues and milestones to consider when consuming LOD:

1. Specify concrete use cases

2. Evaluate relevant data sources and data sets

3. Check the respective licenses

4. Create consumption patterns

5. Manage alignment, caching and updating mechanisms

6. Create mash ups, GUIs, services and applications on top

7. Establish sustainable new partnerships

Consuming LOD from LOD players

• UK Organograms:http://data.gov.uk/organogram/hm-treasury

Consuming LOD from LOD players

• reegle.info country profiles: http://www.reegle.info/countries

Linked Data Publishers

• UK Government

• US Government

• BBC

• Open Calais – Thomson Reuters

• Freebase

• NY Times

• Best Buy

• CNET

• Dbpedia

Reference

1. http://en.wikipedia.org/wiki/Linked_open_data

2. http://lod-cloud.net/

3. http://www.w3.org/wiki/SweoIG/TaskForces/CommunityProjects/LinkingOpenData

4. http://www.w3.org/DesignIssues/LinkedData.html

5. http://linkeddata.org/guides-and-tutorials

6. http://linkeddatabook.com/editions/1.0/

Thank You !