Linked Data and cultural heritage data: an overview of the approaches from Europeana and The European Library

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2 Linked Data and cultural heritage data: an overview of the approaches from Europeana and The European Library Nuno Freire Chief data officer The European Library Pacific Neighbourhood Consortium 2014 Annual Conference Taipei, October 2014

3 Outline Introduction and Context The European Library Europeana The data model for metadata exchange in the Europeana network Linked Data at The European Library Managing and linking person names Managing and linking place names Managing and linking concepts

4 Introduction and context

5 What is The European Library? Project started 1996, full operational service from 2005 European hub of metadata, collections and increasing amount of full text Membership of national and research libraries of 47 Council of Europe states Non-profit, owned and managed by member libraries

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7 What does The European Library offer? Large-scale aggregation Infrastructure Data and digital content of Europe s libraries Data enrichment Linked open data Experienced European project partner Data distribution

8 Open data distribution

9 EUROPEANA - Europe s cultural heritage portal 32.6m records from 2,300 European galleries, museums, archives and libraries Books, newspapers, journals, letters, diaries, archival papers Paintings, maps, drawings, photographs Music, spoken word, radio broadcasts Film, newsreels, television Curated exhibitions 31 languages

10 The European Library as libraries aggregator to Europeana Domain Aggregators National initiatives Libraries National Aggregators e.g. The European Library Archives Regional Aggregators e.g. Culture Grid, Culture.fr e.g. APEX Audiovisual collections Thematic collections e.g. Musées Lausannois e.g. EUScreen, European Film Gateway e.g. Judaica Europeana, Europeana Fashion

11 Metadata in the Europeana Context Provides a portal for users to access that data Metadata, previews and links to source Makes the metadata freely available for anyone to re-use Under Creative Commons Zero (CC0) -public domain dedication Makes metadata available via an API Makes metadata available as Linked Open Data

12 Europeana Data Model: a Collaborative Effort Cross-community development Involving library, archive and museum experts Ca. 60 participants

13 Europeana Data Model: general principles A cross domain approach Supporting the common semantics of cultural domains Addressing the requirements of the Europeana portal Adheres to the modeling principles of the Web of Data Available as an OWL ontology and XML schema Allows finer-grained models of the different domains to be at least partly interoperable at the semantic level Allows metadata to retain their original expressivity and richness

14 Linked Data at The European Library Managing and linking person names

15 Which data from VIAF is used at The European Library Name variants Various forms of the name of the person or organization. May include the complete name, abbreviated names, acronyms, etc. Date of birth/death The dates of birth and death of the person Nationalities The nationalities of a person or organization.

16 How data from VIAF is used in The European Library Name variants For matching of names across records and data sources Improves the identification of all publications of a work, the identification of publications in books-in-print databases, and the identification of the contributor in the rights-holders databases. Date of birth/death Used for determining the public domain status. Used for matching confirmation and disambiguation of homonyms across data sources Nationalities Used, in some countries, for determining the public domain status of the work.

17 The matching process VIAF data used for matching, disambiguation, and match probability

18 Matching work contributors with VIAF Names are matched by similarity Confirmation of the correctness of a name match is taken from other matching data The dates of birth and death The title of the work is compared against the list of titles available in VIAF All the contributors of the work are matched against the list of known co-authors in VIAF The publisher(s) of the work are matched against the list of known publishers in VIAF A match is only chosen if enough supporting evidence is found

19 Contributor names in statements of responsibility French Canadian freely arranged by Katherine K. Davis. ed. by Peter Noever ; with a forew. by Frank O. Gehry; and contrib. by Coop Himmelblau. W. Lange, A.C. Zeven and N.G. Hogenboom, editors by Pamela and Neal Priestland Vicente Aleixandre ; estudio previo, selección y notas de Leopoldo de Luis

20 The approach To approach the problem as a Named Entity Recognition task in text that may not be grammatically correct, thus lacking lexical evidence Some requirements from the ARROW context Easily applicable to several languages The outcomes of the recognition task must be explainable Design decisions Exploring the structured data within national bibliographies By analysis of the frequency of word occurrences in names of persons, and in other textual data Using word occurrence frequency allows to bypass the need for building training sets be able to provide simpler explanations of the name recognition results

21 The process bibliographic record processing The named entity recognition is performed for a record as follows: Statement of responsibility is tokenized The person names are recognized by comparing the tokens with the dictionaries The recognized names are compared against the names of the contributors present in the structured fields of the record. If no similar name exists in the record, the contributor is added to the record in a structured data field

22 Evaluation data set (size of bibliographies and evaluation samples) National Bibliography Total records Main language Evaluation sample Statements of responsibility Referred Persons British Library 13.4 million English German National Library National Library of the Netherlands National Library of Greece Central Institute for the Union Catalogue of Italian Libraries Royal Library of Belgium 9.4 million German million Dutch million Greek million Italian million French and Dutch Total:

23 Evaluation results Dataset Exact match metric Partial match metric Precision Recall Precision Recall British Library German National Library National Library of the Netherlands National Library of Greece Central Institute for the Union Catalogue of Italian Libraries Royal Library of Belgium Overall:

24 Linked Data at The European Library Managing and linking place names

25 The approach for place name linking We process the complete metadata elements The alignment is performed with Geonames Using the RDF dump of Geonames A generic approach not using any language specific information The words themselves are not used as evidence We use only characteristics of the words (capitalization, size, etc) Wordnets, part-of-speech analysis, morphological analysis, etc., are not used. in order to allow the use of this approach in a language independent manner

26 Resolution of the place names This task aims to find a single entity in the geographic ontology for aligning with the place name The first step of this task is to find all possible candidates for the resolution in the geographic ontology Uses a heuristic based predictive model: Assigns a probability for each resolution candidate as match or non_match An alignment is established if a minimum probability threshold for the class match is achieved.

27 Which information supports the place name resolution Feature Number of words Description The number of words in the place name. Name match Exact name match Relative population Geographic feature type Related places found Relative related places If the recognized place name matched: the main name of the place, an alternate name, etc. If the recognized place name matched exactly the place name. Relative population of the candidate in comparison with other candidates. The type of geographic feature: continent, country, city, etc. The number of other place names found in the administrative hierarchy. The relative number of administrative divisions found in the subject heading In source country If it is located in one of the source countries of the subject heading system.

28 Linked Data at The European Library Managing and linking concepts

29 Linking Subject Indexing and Classification Data The context The centralization of bibliographic metadata enables resource access under a unified knowledge organization system The challenges Diversity of languages Diversity of knowledge organization systems in use across European libraries Heterogeneous levels of details in subject information Current status at The European Library Use of alignments between ontologies: Alignments were created manually or semi-automatically Alignments in use include: CERIF, MACS (LCSH, RAMEAU, SWD), UDC and DDC

30 References Further details may be consulted in the following publications: Freire, N, 2014, 'Word Occurrence Based Extraction of Work Contributors from Statements of Responsibility'. International Journal on Digital Libraries: Volume 14, Issue 3 (2014), Page DOI: /s Charles, V., Freire, N, Antoine, I., 2014, 'Links, languages and semantics: linked data approaches in The European Library and Europeana', in 'Linked Data in Libraries: Let's make it happen!' IFLA 2014 Satellite Meeting on Linked Data in Libraries. Freire, N, Muhr, M, 2013, 'Use of Authorities Open Data in the ARROW Rights Infrastructure' in proceeding of the DC-2013 Linking to the Future Conference, Freire, N, 2013, 'Visualization and navigation of knowledge in pan-european resources: the case of The European Library' in proceedings of International UDC Seminar on Classification & Visualization: interfaces to knowledge. N. Freire, et al., "Author Consolidation across European National Bibliographies and Academic Digital Repositories", 11th International Conference on Current Research Information Systems, N. Freire, J. Borbinha, P. Calado, "A Language Independent Approach for Aligning Subject Heading Systems with Geographic Ontologies", International Conference on Dublin Core and Metadata Applications 2011, N. Freire, J. Borbinha, P. Calado, B. Martins, "A Metadata Geoparsing System for Place Name Recognition and Resolution in Metadata Records", ACM/IEEE Joint Conference on Digital Libraries, 2011.

31 Thank you Nuno Freire Chief data officer