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Semantic Web and data model

Summary

Resource description framework (RDF) and the semantic web in the data.bnf.fr project

The data.bnf.fr project has to be placed in the context of our move towards open data. This approach has been defined by the W3C, regarding the “semantic web” or “linked data”.
This is about structuring resources in order to make them reusable by machines in a better way. The data.bnf.fr project uses data which have been created in various formats such as InterMarc for the main catalogue, XML-EAD for archives inventories and Dublin Core for the digital library.
Such data is automatically gathered, modeled and enriched and are published in the RDF semantic web language. The result is available on the website, in different RDF syntaxes: RDF-XML, RDF-N3, and RDF-NT.

The Bibliothèque nationale de France provides:

  • URIs for resources: all resources have permanent identifiers, granted via the ARK process which is the way to find all resources of the library.
  • a display of data in RDF as “linked open data”. It is available for every page and for the whole database

    • The software is: CubicWeb

    CubicWeb It is a open source platform for semantic web applications under LGPL licence.

    logo cubicweb

    CubicWeb has won the Dataconnexions 2013 awards , organized by Etalab, the mission for Open Data promotion under the authority of the French Prime Minister.

    How to retrieve data.bnf.fr data (downloading dumps and pages)

    You can retrieve our data, by:

  • by clicking on the RDF icon, at the bottom of the pages
  • by adding the following suffixes to the URL: NT, N3, RDF-XML, according to the format needed. For instance:
    http://data.bnf.fr/11928016/jules_verne/rdf.xml,
    http://data.bnf.fr/11928016/jules_verne/rdf.nt,
    http://data.bnf.fr/11928016/jules_verne/rdf.n3.
  • via content negotiation, using a RDF web browser, from the URL.
  • by using the following URL to retrieve the complete dump:
    • >

    A dump of all data in data.bnf.fr is also available on our FTP server: hôte : echanges.bnf.fr, port : 21
    login : databnf, password : databnf
    et via HTTP: whole dump rdf (rdf/xml)

    This dump is split in dumps for every kind of data :

  • Links to external web sites :dumps rdf-nt, dump rdf-n3, dump rdf-xml.
    Il comprend :
    • Agrovoc matching
    • Thesaurus W matching matching
    • Library of Congress matching
    • German national library (DNB) matching
    • Geonames matching
    • DBpedia matching
    • Wikipedia matching
    • VIAF matching
    • IdReF matching
    • Dewey matching

    The license to use the data is available here ici.


    ftp host : echanges.bnf.fr , port : 21
    login : databnf, mot de passe : databnf

    and HTTP: full rdf dump (rdf/xml)

    The license to use our data is available here.

    Links to external sites and repositories

    Our data is linked to the equivalent pages in other data repositories. They are matched to external datasets.id.loc.gov for languages and country codes, dewey.info for subjects headings, DCMI type for all kinds of documents.
    It is also aligned to data sets that are found in CKAN, in particular dbpedia and VIAF.

    RAMEAU subject headings are matched to:

    A matching between the global categories of the Dewey classification and RAMEAU subject headings has been created(http://dewey.info).
    Example: the RAMEAU subject « Architecture » is matched with the Dewey subject« Architecture ».

    Data about authors is also linked to:

    • VIAF, Virtual Identifier for Authority File
    • IdRef, the authority repository of the higher education libraries.
    • DBpedia et Wikipedia

    URI and URL in data.bnf.fr

    ARK identifiers and URIs

    The BnF identifies bibliographic and authority descriptions and digital documents with ARK identifiers.

    This identifier is build this way:

    For further information about ARK identifiers at the BnF (French).

    This record identifier is also used inside the BnF to link different records and different databases together.
    Example:
    the record http://catalogue.bnf.fr/ark:/12148/cb30625225, is linked to the record « Victor Hugo »:
    100 $311907966 $w.0..b.....$aHugo$mVictor$d1802-1885$40070

    In data.bnf.fr, URIs are built with the ARK of the authority record of the Main catalogue. They identify the concepts that are described in the “skos: concept” class, in our data model.

    Example:
    the authority record Victor Hugo http://catalogue.bnf.fr/ark:/12148/cb11907966z and the "concept" of Victor Hugo in data.bnf.fr http://data.bnf.fr/ark:/12148/cb11907966z are built on the same ARK identifier.
    they are permanent identifiers, HTTP, actionable and enable to display our pages on the semantic Web.

    URL, Web redirection and content negotiation

    To facilitate pages indexing by search engines, data.bnf.fr URL have explicit labels.
    The URL of work, author and themes pages is made this way: http://data.bnf.fr/ID/label

    Example:
    Person: http://data.bnf.fr/ ID / first name (100$m) _ name (100$a)
    Organization: http://data.bnf.fr / ID /name(110$a)
    Work : http://data.bnf.fr/ ID /title (245$a or 14X$a)_secondary elements of the title ($i)
    For Victor Hugo:
    http://data.bnf.fr/11907966/victor_hugo/

    there is a HTTP redirection mechanism from ARK identifiers and URIs to URL:


    http://data.bnf.fr/ark:/12148/cb11907966z via HTTP 303 leads to http://data.bnf.fr/11907966/victor_hugo/
    http://data.bnf.fr/11907966 via HTTP 303 leads to http://data.bnf.fr/11907966/victor_hugo/
    http://data.bnf.fr/11907966/victor_hugo via HTTP 301 leads to http://data.bnf.fr/11907966/victor_hugo/

    We have a content negotiation mechanism:
    http://data.bnf.fr/11907966/victor_hugo/” brings a representation of the page that depends on the HTTP header.
    For instance :


    http://data.bnf.fr/11907966/victor_hugo/fr.html
    http://data.bnf.fr/11907966/victor_hugo/en.html
    http://data.bnf.fr/11907966/victor_hugo/rdf.xml
    http://data.bnf.fr/11907966/victor_hugo/rdf.n3
    http://data.bnf.fr/11907966/victor_hugo/fr.pdf
    http://data.bnf.fr/11907966/victor_hugo/en.pdf
    There isn’t any language for the RDF files.

    We also use redirection for URLs that are likely to be used, for instance: data/1234/victor_hugo.html => data/1234/victor_hugo/fr.html data/1234/victor_hugo.rdf => data/1234/victor_hugo/rdf.xml data/1234/victor_hugo.n3 => data/1234/victor_hugo/rdf.n3 data/1234/victor_hugo.pdf => data/1234/victor_hugo/fr.pdf

    The FRBR construction and author, work and subject concepts

    The FRBR model

    Data.bnf.fr is carried out in the context of the recent evolutions of bibliographic description, by experimenting and adapting the FRBR (Functional requirements for Bibliographic Records) model, elaborated by the IFLA (International Federation for Library Associations).
    The model has three entity groups which are linked together by relationships: information about documents, persons and organisations, and subjects.

    • “Work” pages

    The first group of the FRBR model describes the different aspects of an intellectual or art creation, and discerns 4 levels: work, expression, manifestation and item.

    The work level is about the intellectual and artistic creation. For instance: Le colonel Chabert by Honoré de Balzac. “Work” pages are created using the related authority records from the BnF Main Catalogue.

    The expression level (different versions of this work such as a translation, an adaptation or an abridgment) does not appear in the html pages but can be seen in the corresponding RDF pages.

    The manifestation level is the physical embodiment of a work. For instance an edition of Les Misérables like “Nouvelle impression illustrée. 1879-1882. Paris. E. Hugues”. The manifestations are listed in the documentary unit and gathered in the section entitled “Vie et éditions de l’œuvre” (Life and editions of the work). This level corresponds to the bibliographic record in the BnF Main catalogue, or to a manuscript that is identified by a label in the Archives and Manuscript Catalogue (BnF archives et manuscrits).

    There can be a part-whole relationship between:
  • a work and another work. For example: Le Père Goriot (Honoré de Balzac), is part of the work Scenes de la vie privée, by the same author, and both are considered as works and have a page in data.bnf.fr.
  • a manifestation and another one. For example: a specific edition of Le Père Goriot (Honoré de Balzac) is part of the manifestation Etudes de moeurs which is an edition gathering several texts by Balzac.
    • “Author” pages:

    A person or an organisation can be either the “author” of a work (then there is a link between the “author” page and the related “work” page) or “contributor” of an expression (translator, preface writer, librettist…).
    Nevertheless, as the expression level is not different from the manifestation level in the html pages of data.bnf.fr, contributors do only appear at the manifestation level. The different creation or contribution roles are listed in a BnF repository, in the Intermarc format, and in the Library of Congress repository, in Marc. This kind of data enriches the RDF of the pages.

    Link to the Intermarc code list for relators and creators (BnF).

    Link to the Marc code list for relators of the Library of Congress.

    • “Subject” pages

    Among retrievable data, there are subjects records from the Bibliothèque nationale de France (RAMEAU, which is the French indexation language). They have been converted into the RDF language SKOS (Simple Kowledge Organisation), in the context of the European project TELplus. This repository is now updated on data.bnf.fr with the whole current database from the Bibliothèque nationale de France.
    In order to get dereferenceable URIs in our website, URIs from the initial project such as http://stitch.cs.vu.nl/vocabularies/rameau/ark:/12148/cb12650268p, have to be converted to simple and uniform URIs with: the root: http://data.bnf.fr and the ARK identifier of the authority subject record.
    For instance:
    The URI http://stitch.cs.vu.nl/vocabularies/rameau/ark:/12148/cb12650268p, the subject “ornithologie”, will be replaced by: http://data.bnf.fr/ark:/12148/cb12650268p.
    Manifestations which have a RAMEAU term as a subject are brought together in the appropriate “subject” page.

    Moreover the site holds pages that gather works and manifestations about a work or an author. These pages are not indexed by search engines and are available from the “work” or “author” pages.
    For instance: on the page “Napoleon”, there is a link towards a page presenting documents about Napoleon such as Vie de Napoléon Buonaparte, 1827.

    Alignments and clustering by work

    In “work” and “author” pages, all manifestations by a single author are gathered around his works, thanks to the explicit link to title authority record (Titre Conventionnel or TIC, in French) , inside the original bibliographic record.

    In the meantime some manifestations are not linked to the title authority record and remain “orphan”. In order to improve the way our data is translated in FRBR and to bring a better service to the public, it is important to align these orphan manifestations, which means bringing them together around the corresponding work.

    Example:
    Bibliographic record (BnF) with a link to the title authority record “Fables” and the author authority record “Jean de La Fontaine”.
    Bibliographic record (BnF)without any link to the title authority record “La cigale et la fourmi” but with a link to the author authority record “Jean de La Fontaine”.

    That is why we have already produced simple alignments in data.bnf.fr . When a manifestation is explicitly linked to an author authority record in the bibliographic record, and when the character string of this manifestation is exactly the same as the work’s title, then the manifestation is aligned with the work.

    Yet, after this simple alignment, many manifestations remain orphan. In the long term two solutions are possible:

  • alignment: : It means attaching manifestations to a work which has its own title authority record and, thus, its own page. These manifestations do not have any link to the title authority record: they come from bibliographic records of the Main catalogue or from descriptions of “BnF Archives et Manuscrits”.
    We use a simple and advanced alignment algorithm (word beginning with, exact match, words with a X distance, Levenstein distance, matching algorithm) to determine whether two character strings correspond to the same work. The link to the author authority record remains essential to align works.
  • clustering: if there is no title authority record, some manifestations are gathered around a new documentary unit

    • RDF datamodel

    The data model is presented here:

    schema ontologie

    Example 1 : Victor Hugo, author of Les Contemplations.

    Example 1 : Victor Hugo, author of Les Contemplations.


    Example 2 : Charles Baudelaire, writer of the preface of an edition of the "Gold-Bug" by Edgar Allan Poe.

    Exemple de graphe 2 : Charles Baudelaire, préfacier d’une édition du Scarabée d’or d’Edgar Poe.

    The full data model is available here.

    Consulter le schéma complet du modèle de donnée.

    Ontologies and vocabularies

    We preferred to reuse existing vocabularies in order to foster interoperability.
    rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns;
    rdfs: http://www.w3.org/2000/01/rdf-schema;
    skos: http://www.w3.org/2004/02/skos/core;
    dc: http://purl.org/dc/dcmitype/";
    foaf: http://xmlns.com/foaf/0.1/;
    RDAgroup2elements http://RDVocab.info/ElementsGr2/;
    RDVocab: http://RDVocab.info/Elements;

    Nevertheless some properties and classes have to be expressed by an ontology specific to the BnF: bnf-onto. To publish the ontology, the BnF has chosen the harmonized namespace http://data.bnf.fr/ontology/.

    Presentation of the BnF ontology: bnf-onto

    The ontology "bnf-onto" can be seen at this address : http://data.bnf.fr/ontology-en".
    List of properties:

  • isbn = International standard book number). http://data.bnf.fr/ontology/bnf-onto/isbn.
  • imgAlt = alternative text for images. http://data.bnf.fr/ontology/bnf-onto/imgAlt.
  • ean = EAN, European article numbering (Bar Code). http://data.bnf.fr/ontology/bnf-onto/ean.
  • cote = shelfmark of an archival document: unique number identifying the item which is kept in the collections.http://data.bnf.fr/ontology/bnf-onto/cote.
  • depiction = The preferred thumbnail for a page, chosen manually.http://data.bnf.fr/ontology/bnf-onto/depiction.
  • issn = International standard serial number.http://data.bnf.fr/ontology/bnf-onto/issn.
  • ismn = International standard music number (printed music).http://data.bnf.fr/ontology/bnf-onto/ismn.
  • expositionVirtuelle = URL for a virtual exhibition of the BnF.http://data.bnf.fr/ontology/bnf-onto/expositionVirtuelle.
  • anl = an ANL stands for a sub-record that gives access to a specific part of document (illustration of a book, text embedded in a book…).http://data.bnf.fr/ontology/bnf-onto/anl.
  • ouvrageJeunesse = an adapted edition of a work for the younger public. Meant to sort editions, which often offer a different content even though the title is the same.http://data.bnf.fr/ontology/bnf-onto/ouvrageJeunesse.
  • code_role = coded role describing a contribution of a person/organisation in a work.
    Numeric values are used to describe relators.
    Completed by the mark-up related to the code list for contributors and creators of the Library of Congress. http://data.bnf.fr/ontology/bnf-onto/code_role.
  • role = the French label of contribution roles.http://data.bnf.fr/ontology/bnf-onto/role.

    • Bibliothèque nationale de France vocabularies

    BnF specific vocabularies are displayed at this address : http://data.bnf.fr/vocabulary-en.
    List of vocabularies:

  • Country codes list: http://data.bnf.fr/vocabulary/countrycodes
  • Relator codes list: http://data.bnf.fr/vocabulary/roles
  • Types of RAMEAU subject headings: http://data.bnf.fr/vocabulary/scheme

    • Embedded data: schema.org and Opengraph Protocol

    “Author”, “work” and “subject” pages are open on the Web and can be reached by search engines.
    This is why, except from the traditional methods used for indexing the homepage, we have chosen to embed two kinds of data to structure these pages:

  • Schema.org, provides a vocabulary to add information to the HTML content, with a microdata format, to foster the indexing by search engines.

    • The following elements are used:

    itemtype=http://schema.org/Person
    itemprop="description" itemprop="birthdate" itemprop="deathdate" itemprop="nationality" itemprop="memberOf"

    itemtype=http://schema.org/Book
    itemprop="description" itemprop="inLanguage" itemprop="datePublished" itemprop="genre"

    itemtype= http://schema.org/Organization
    itemprop="description" itemprop="image" itemprop="name" itemprop="url" itemprop="members" itemprop="founding date" itemprop="founders"

    And for sub groups of the organizations:
    itemscope itemtype= http://schema.org/PerformingGroup itemscope itemtype= http://schema.org/DanceGroup itemscope itemtype= http://schema.org/TheaterGroup itemscope itemtype= http://schema.org/MusicGroup

  • Opengraph Protocol (OG), so that the pages can be represented in social networks.

    • It is a very simple vocabulary to encode in RDFa metadata to be retrieved when the user adds the resource to its Facebook profile. The following metadata is embedded in the HTML header, thanks to META markups:

    og: title (title of the page)
    og: description (description of the page content)
    og: type (type of resource)
    og: url (page URL)
    og: image (URL of the image that illustrates page)
    og: author (name of the author in the “work” page)

    How bibliographic and authority data is transformed and handled in data.bnf.fr?

    Data.bnf.fr relies on bibliographic data that is structured and linked together, on order to build pages about authors, works and themes. In particular:

    • The structure: fields and sub-fields in the MARC format.

    For instance the page gathering all documents about an author or a work is created automatically, using all bibliographic records that are linked in the field 6XX to the authority record of a person or a work (which is the field for subject indexing in Intermarc, the a MARC adapted for the BnF).
    • The links: between bibliographic records (main catalogue) or Finding aids (for archives and manuscripts) and the authority records.

    Thanks to reliable links to person and works authority data we can gather the bibliographic descriptions of documents in pages about authors and works.
    Example: the description of the edition « l’Alchimiste » (http://catalogue.bnf.fr/ark:/12148/cb31009441) by Alexandre is linked to the authority record of Alexandre Dumas (http://catalogue.bnf.fr/ark:/12148/cb119010630), in the field 100 $3 (Intermarc).
    In Intermarc: 100 $311901063 $w.0.2b.....$aDumas$mAlexandre$d1802-1870$40070
    • Role codes specifying these links:

    The different activities that can be found in pages about an author correspond to different types of roles of persons or organizations on a document (translator, author of a preface, illustrator…).
    They come from the role codes that specify the link between a bibliographic record and an authority record.
    These codes are displayed here: http://data.bnf.fr/vocabulary/roles.
    Example: Baudelaire translated « Dix contes d'Edgar Poe » (http://catalogue.bnf.fr/ark:/12148/cb311263053).
    The bibliographic record of the document is linked to the authority record of Charles Baudelaire, with the role code « 0680 », which means « translator ».
    700 $311890582 $w 0 b.....$aBaudelaire$mCharles$d1821-1867$40680

    Mappings between the InterMarc format and the RDF

    We provide mappings between the Intermarc format used at the BnF for bibliographic records, the Unimarc format, commonly used to exchange data between libraries and the RDF vocabularies that are used in data.bnf.fr.

    You will find:

    • the mapping from RAMEAU subject headings to RDF
    • the mapping from title (text and music), person, organisation authority records to RDF.
    • the mapping from the bibliographic records to RDF