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Linked Data as An Element to Support Resource Discovery: The Need for

Harmonization of Metadata Standards

Praveenkumar VaidyaLibrarian, Tolani Maritime Institute, Pune

and Dr. N. S. Harinarayana, Associate Professor,

DOS LIS, University of Mysore, Mysore

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• Introduction• Libraries and Linked Data• Metadata, Interoperability, crosswalks and

harmonization• Conclusion

Preview

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• Information deluge and information overflow.• Challenge in Information Retrieval.• Lee’s vision: Semantic Web may be one of the

solutions, where even machines can answer the queries.

• Bibliographic and subject standards are used in library world are translated into the language of Semantic Web and Linked Data.

Introduction

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• Linked Data is growing body of datasets on the WWW that are interconnected by means of the Resource description Framework (RDF). (W3C, 2004)

• RDF-grammar for a language of data- consists-subject, predicate, object-to form-RDF graph.

• LCSH-2009-Published library standards in RDF. • W3C-2011-Linked Data Incubator group-

accepted-RDF as tool-integration of Library Data.

Introduction…

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• Basically, to create highly structured metadata.• To allow computers to understand the relation

between objects to yield precise web search.• W3C-working on RDF-allows computer to

understand the meaning of the content rather just matching text-Result: Web search engine works like RDBMS-Throws precise search result.

Libraries and Linked Data

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• As Freie Universitat Berlin defined- First, to employ the RDF data model to publish structured data of the Web. Second, to (use http URIs) to set explicit RDF links between data items within different data sources”

• This gives two distinct aspects of Linked Data: exposing data as RDF and linking RDF entities together.

Libraries and Linked Data…

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• Sharable, extensible and easily re-usable. With the concepts like language-agnostic URIs, it supports multilingual functionality for data and user services.

• A query can draw related information from any link that is available on the world wide network of data, to get useful results from the web.

Benefits of Linked Data…

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• Links between libraries and non library services- Wikipedia, Geo names, MusicBrainz, the BBC and The New York Times will connect into larger universe of the information on the Web which seamlessly flow to local user.

• If, information Hub linked between Publishers, Aggregators, Book and Journal vendors, Subject Authorities, Name Authorities and other Libraries

• Can handle selection, ordering, cataloguing, authority control, taxonomy development and search. Can also handle intelligent queries.

Benefits of Linked Data…

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• Despite movements like DCMI and FRBR-Linked Data compatible-Not much has been integrated with web resource-still in databases.

• Existing library standards such as MARC format or information retrieval protocol Z39.50 are developed for library specific context -standards should be broadened and standardized to Linked Data format.

Current Status of Libraries

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• There is disparity in concepts and terminologies used between libraries and Semantic Web communities.

• Essential for both communities to foster mutual understanding to bring their respective expertise.

• Some hiccups like privacy, trust, rights management and collaboration with multiple users exist in full fledge adoption of Linked Data, much effort is required.

Current Status of Libraries…

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• Libraries have four major roles in the Linked Data– Exposing collections- use Semantic Web

technologies to make content available– Webifying thesaurus/mapping /services– Sharing lessons learned– Persistence (Miller, 2004)

Towards standardization

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• W3C Library Linked Data incubator group (W3C, 2011) insists on Semantic Web standardization by using available standards such as Simple Knowledge Organisation System (SKOS), Web Ontology Language (OWL) and RDF.

• However, lack of institutional support for metadata can threaten the long term persistence.

Towards standardization…

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• In the networked information environment, both contents and services are identified as resources

• Linking these resources is crucial• Metadata is the key to identify and link these

resources – Across domains and over time

Metadata interoperability

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Metadata – Fundamental Model

• Definition: (Structured) Data about Data• Description about a resource from a certain

point of view in accordance with the requirements in the domain

resourceMetadata Metadata

Metadata – Fundamental Model

Bibliographic Information Book Reviews

Teaching / Learning Requirements

I want to find a book about history of India.

I want to find a book appropriate for my class.

I want to buy a book about India for my trip.

I want to properly sort my bookshelf.

Book Classification

Different purposes for a single object

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Metadata – Fundamental ModelDifferent objects for a same purpose

I want to find a content to learn history of India.

I want to buy a content appropriate for my class.

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Why Metadata?

• Users search, access, evaluate a resource, and pay money for the resource on the network

• Can we do anything without metadata?

Tasks over the Net17

Metadata Interoperability – Fundamental Issue

• Standards are crucial for interoperability– International / national standards of metadata schemas, e.g.

MARC, MODS, METS, Dublin Core, ISAD(G), PREMIS, OAIS, etc.• Metadata is used on the Web / Internet Open Community, Use/Reuse resource across communities– Conventional standards are designed by and for a specific

community (-ies)• Metadata Interoperability across Communities and over Time

– Need to collect, preserve and provide access to metadata schemas

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Metadata Interoperability…

• Interoperability is a key issue for metadata– Interoperability across communities– Interoperability over time --- Preservation

• A fundamental barrier is the semantic gap between communities– Same word but different concepts– Different words for a same concept– Linked Open Data – Sharing concepts expressed as

data, i.e., terms, phrases, etc.

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Metadata Interoperability…

• Promote sharing and reuse of metadata vocabularies– Metadata vocabulary – a controlled set of terms used

to express metadata – is semantic basis of metadata– “Sharing Metadata Vocabulary” = “Sharing Concepts”

• Application Profile concept of Dublin Core– Mixing and matching metadata vocabularies– Clear separation of metadata vocabularies and

structural constraints in a metadata schema– Share semantics by sharing metadata vocabularies

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Metadata Interoperability…

• Resource Description Framework is a crucial standard to share metadata on the Web.

• Application Profile is separation of– Metadata terms (metadata vocabulary), and– Structure definition (or structural constraints)

• Concrete syntax and other related information should be included in a complete metadata schema definition.– Singapore Framework gives a framework to define

application profileshttp://dublincore.org/documents/singapore-framework/

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• YES, but we have more to do than simply linking.• No panacea for metadata interoperability.• Use standards commonly used on the web.• Do not reinvent the metadata schemas.• Use or reuse the existing one– By sharing Metadata vocabularies and Application

Profiles• Necessity of all available standards to come

together and integrate with different domains.

Is Linked Data the answer?

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• I thank Prof. Shigeo Sugimoto, University of Tsukuba, Japan allowing me to use few of his slides for this presentation.

Acknowledgement

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References:• Berners-Lee, T. (2006), “Linked Data–design issues”, available at:http://www.w3.org/

DesignIssues/LinkedData.html • DCMI Bibliographic Metadata Task Group (2011), available at http://

wiki.dublincore.org/index.php/Bibliographic_Metadata_Task_Group• Library of Congress (2011), “A bibliographic framework for the digital age”, available at: • http://www.loc.gov/marc/transition/news/framework-103111.html• Nilsson,M and Naeve, A. (2010) Metadata harmonization:a roadmap for standardization

available at Nilsson, M. (2010), “From interoperability to harmonization in metadata standardization:Designing an evolvable framework for metadata harmonization,” Kungliga TekniskaHögskolan, Stockholm, available at:http://kmr.nada.kth.se/papers/SemanticWeb/FromInteropToHarm-MikaelsThesis.pdf

• W3C (2010) Semantic Web, available at http://www.w3.org/standards/semanticweb/• W3C (2011) Library Linked Data Incubator Group Final Report, W3C Incubator Group Report

25 October 2011, available at: http://www.w3.org/2005/Incubator/lld/XGR-lld-20111025/

References:

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Thank you very much