What Is Linked Data, and What Does it Mean for Libraries? ALAO TEDSIG Spring Meeting

What is Linked Data,

and What Does It Mean for Libraries?

Emily Dust NimsakontALAO TEDSIG Spring

MeetingMay 27, 2011

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This is an overview…

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• What is Linked Data?• How do we create Linked Data?• Examples of Linked Data• What does Linked Data mean for libraries?• Are there drawbacks to Linked Data?• What’s next?• What can I do?

What is Linked Data?

Wikipedia says…

“Linked Data describes a method of publishing structured data, so that it can be interlinked

and become more useful. It builds upon standard web technologies, such as HTTP and

URIs - but rather than using them to serve web pages for human readers, it extends them to share information in a way that can be read

automatically by computers.”

http://en.wikipedia.org/wiki/Linked_Data

The inventor of the Web said…

“I have a dream for the Web [in which computers] become capable of analyzing all

the data on the Web – the content, links, and transactions between people and computers.”

Tim Berners-Lee, 1999

Linked Datavs.

Semantic Webvs.

Web 3.0

web of documentsvs.

web of data

resource

resource

resource

resource

resource links to

links to

links to

links to

data links to

links to

links to

links to

data data

data

datadata

datadata

datadata

data

data

hypertextvs.

hyperdata

HTML

<h1>This is a heading.</h1>

<p>This is a paragraph.</p>

RDF/XML

<rdf:Descriptionrdf:about="http://www.recshop.fake/cd/Empire Burlesque"> <cd:artist>Bob Dylan</cd:artist> <cd:country>USA</cd:country> <cd:company>Columbia</cd:company> <cd:price>10.90</cd:price> <cd:year>1985</cd:year></rdf:Description>

http://www.w3schools.com/rdf/rdf_example.asp

Relationships are key

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People can understand relationships between things.

But machines should be able to understand these relationships too.

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We are used to connecting pieces of information based on their context.

Title: A Christmas CarolAuthor: Charles Dickens

Linked Data makes the relationships explicit.

1. Data instead of documents2. Encoded meaning3. Relationships are key

So what?

Linked Data makes the Web into a database.

“Linked Open Data turns the Web into an API.”

Corey A. Harperas quoted in

http://www.slideshare.net/eby/why-libraries-should-embrace-linked-data

Linked Data allows you to customize the Web.

“Link your data to other people’s data to provide context.”

Michael Hausenblashttp://webofdata.wordpress.com/2011/05/22/why-we-link/

Questions?

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How do we create Linked Data?

Linked Data principles

Tim Berners-Lee, “Linked Data-Design Issues.” http://www.w3.org/DesignIssues/LinkedData.html

Use URIs as names for

things

Use HTTP URIs so people can look up these names

When someone looks up a URI, provide

useful information, using the standards

Include links to other URIs, so that they can discover more

things

URIs

For Linked Data, we need to be able to identify things uniquely

Uniform Resource Identifiers do this already

URIs

Using HTTP URIs is one of the principles of Linked Data

http://www.example.com/thing1

URIs

URIs are like control numbers (LCCN, ISBN, etc.).

RDF

Resource Description Framework

Describes relationships based on triples (statements):

subject-predicate-object

http://www.w3.org/RDF

RDF

subject object

A Christmas Carol

Charles Dickens

has author

predicate

RDF statements

The subject and predicate must be URIs.

The object can be a URI or a value.

RDF graphs

Charles Dickens

A Christmas

Carol

has author has

publisher

Penguin

RDF

<rdf:Descriptionrdf:about="http://www.recshop.fake/cd/Empire Burlesque"> <cd:artist>Bob Dylan</cd:artist> <cd:country>USA</cd:country> <cd:company>Columbia</cd:company> <cd:price>10.90</cd:price> <cd:year>1985</cd:year></rdf:Description>

http://www.w3schools.com/rdf/rdf_example.asp

Vocabularies

Specific terms to be used to describe resources

Sound familiar?

Vocabularies

• Dublin Core• Simple Knowledge Organization System (SKOS)• RDF Schema (RDFS)• Friend of a Friend (FOAF)• Web Ontology Language (OWL)

<rdf:RDF xmlns:dcterms="http://purl.org/dc/terms/" xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:skos="http://www.w3.org/2004/02/skos/core#">

<skos:prefLabel> Knitting</skos:prefLabel>

SPARQL

• SPARQL is a query language (like SQL) used to search the semantic web

• SPARQL endpoints are provided for Linked Data resources

Link to other resources

1. Relationship Links2. Identity Links3. Vocabulary Links

Questions?

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Are there examples of Linked Data/

Semantic Web?

DBpedia

http://dbpedia.org

Faviki

http://www.faviki.com

Zemanta

http://www.zemanta.com

FreeBase

http://www.freebase.com

Questions?

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What could Linked Data

mean for Libraries?

Part I:What could Linked Data

mean for Library Data?

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Getting rid of silos

“Our services must not only be on the Web, but need to be of the

Web.”- Karen Coyle

RDA Vocabularies for a Twenty-First-Century Data EnvironmentLibrary Technology Reports

February 2010

Library Catalogs

World Wide Web

More open standards

bibliographic recordsvs.

bibliographic data

In traditional cataloging, a record is one package.

Author

Title

Bibliographic Record

Bibliographic Record

Records can be exchanged, but there is no way to exchange the individual pieces of information within a record.

Bibliographic Record

Bibliographic Record

Person

Is author of

Title

Bibliographic Record

With Linked Data, a bibliographic record is made up of many pieces of data.

And the relationships between these pieces of data are defined.

Person

Is author of

Title

Bibliographic RecordThe boundaries of the record can be dissolved…

Person

Is author of

Title

Bibliographic Record…and the data can interact with other information on the Web.

Are there examples of Linked Data in

libraries?

Library of Congress Authorities and Vocabularies

http://id.loc.gov/

Library of Congress Authorities and Vocabularies

http://id.loc.gov/

RDA Metadata Registry

http://metadataregistry.org/rdabrowse.htm

Virtual International Authority File

http://viaf.org

Dewey Summaries

http://dewey.info

So there’s a bunch of data out there.

Now what?

http://richard.cyganiak.de/2007/10/lod/

Extensible Catalog

http://www.extensiblecatalog.org

What does Linked Data look like?

“That is kind of like asking what electricity looks like: it doesn’t so much look like anything, as it makes certain things possible.”

Karen CoyleVisualizing Linked Data

http://kcoyle.blogspot.com/2011/04/visualizing-linked-data.html

What does Linked Data look like?

http://openlibrary.org

Civil War Data 150

http://www.civilwardata150.net

Part II:What Could Linked Data

Mean for Librarians?

Different workflows

Catalogers could use URIs for things like authors’ names or subject headings.

If information changed, the URI could be changed and automatically update the

information in our catalogs.

Evaluating metadata

Metadata could come from various sources.

“Professional cataloging might be more of a job of aggregating and improving harvested or

contributed metadata, rather than developing new metadata, like MARC records, for

resources.”-Virginia Schilling

“The Catalogers’ Revenge: Unleashing the Semantic Web”PNLA Quarterly 74:3, 2010

http://unllib.unl.edu/LPP/PNLA%20Quarterly/schilling74-3.pdf

Federated searching

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New homes for librarians’ skills?

“Someday there will be a Dewey Decimal number for everything – not just for books.”

http://www.pcworld.com/businesscenter/article/206230/the_internet_needs_a_dewey_decimal_system.html

Are There Drawbacks to Linked

Data?

Training and Software Development

“Nobody but the geekily inclined is going to be willing to invest the time and effort necessary to code semantically tagged web pages from

scratch.”

Virginia Schilling“The Catalogers’ Revenge: Unleashing the Semantic Web.”

PNLA Quarterly 74:3 (Spring 2010).

Access to the Data

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Different Standards and Vocabularies

http://www.dlib.indiana.edu/~jenlrile/metadatamap/

Reliability of Data

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What’s next?

Library Linked Data Incubator Group

http://www.w3.org/2005/Incubator/lld/

International Linked Open Data in Libraries, Archives, and Museums Summit - June 2-3, 2011

http://lod-lam.net

Linked Data at ALA Annual 2011

What can I do?

5 Stars of Open Linked Data

★ Available on the web (whatever format), but with an open license

★★ Available as machine-readable structured data (e.g. Excel instead of image scan of a table)

★★★ Available as (2) plus non-proprietary format (e.g. CSV instead of Excel)

★★★★ All the above plus, Use open standards from W3C (RDF and SPARQL) to identify things, so that people can point at your stuff

★★★★★ All the above, plus: Link your data to other people’s data to provide context

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

Laura Smart, California Institute of TechnologyManaging Metadata

http://library.caltech.edu/laura/

Resources• Jeffrey T. Pollock. Semantic Web for Dummies.• Toby Segaran, Colin Evans, and Jamie Taylor.

Programming the Semantic Web.• Tom Heath and Christian Bizer. Linked Data:

Evolving the Web into a Global Data Space.• Karen Coyle. “Understanding the Semantic

Web: Bibliographic Data and Metadata” and “RDA Vocabularies for a Twenty-First-Century Data Environment.” Library Technology Reports, ALA TechSource.

Linked Data is on the horizon.

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And it has the potential to greatly change how libraries work.

Thank you!

Emily Dust Nimsakontemily.dust.nimsakont@nebraska.gov

http://www.delicious.com/enimsakont/linkeddata+tedsighttp://www.slideshare.net/enimsakont