=Paper=
{{Paper
|id=Vol-1656/paper4
|storemode=property
|title=Dati.CulturaItalia: a Use Case of Publishing Linked Open Data Based on CIDOC-CRM
|pdfUrl=https://ceur-ws.org/Vol-1656/paper4.pdf
|volume=Vol-1656
|authors=Sara Di Giorgio,Achille Felicetti,Patrizia Martini,Emilia Masci
|dblpUrl=https://dblp.org/rec/conf/ercimdl/GiorgioFMM15
}}
==Dati.CulturaItalia: a Use Case of Publishing Linked Open Data Based on CIDOC-CRM==
https://ceur-ws.org/Vol-1656/paper4.pdf
Dati.CulturaItalia: a Use Case of Publishing
Linked Open Data Based on CIDOC-CRM
Sara Di Giorgio1 , Achille Felicetti2 , Patrizia Martini1 , and Emilia Masci3
1
Central Institute for the Union Catalogue of Italian Libraries (ICCU)
of the Italian Ministry of cultural heritage, activities and Tourism
(MiBACT), Rome, Italy
2
PIN, VAST-LAB, Prato, Italy
3
MIUR, Italy
{sara.digiorgio,patrizia.martini}@beniculturali
{achille.felicetti}@pin.unifi.it
{emilia.masci}@gmail.com
Abstract. In this paper we describe the pilot project dati.culturaitalia.it,
which started in 2012 to build up a Linked Open Data (LOD) Service
that will progressively make available open datasets from the web-portal
CulturaItalia 1 , the Italian national aggregator for Europeana 2 . CIDOC-
CRM Ontology was used for transformation and representation of data
widely pertaining to the cultural domain. RDF triples mapped into Er-
langen CRM were then enriched with links to URIs identifying instances
of internationally established RDF resources for geographic names, and
instances of authority files for personal and corporate names, such as
GeoNames and Virtual International Authority File (VIAF). Cultur-
aItalia is the Portal of Italian Culture, promoted by the Italian Ministry
of cultural heritage, activities and tourism (MiBACT), in which cultural
institutions from all sectors and levels (national, regional and local) are
involved. CulturaItalia also plays an important role for the development
of Europeana, making available cooperative networks and agreements
and coordinating technical activities leading to the establishment of Eu-
ropeana environment.
Keywords: System interoperability, Data integration, Cross domain
portal, CIDOC-CRM, Metadata Crosswalks, Linked Open Data, Seman-
tic Web
1 Introduction
CulturaItalia [1], is the portal of the Italian Culture on-line since April 2008,
managed by the Italian Ministry of cultural heritage, activities and tourism
(MiBACT) through the Central Institute for the Union Catalogue of Italian Li-
braries (ICCU) [2]. The Web-portal indexes the main cultural databases and
1
http://www.culturaitalia.it
2
http://www.europeana.eu
Di Giorgio et al.
gathers the metadata to Europeana, the public digital library promoted by the
European Community. CulturaItalia is targeted to general users, by offering
them a service for retrieving information on Italian culture from one access-
point, and to more expert users, such as the operators in the cultural field,
who can take advantage of a high-quality showcase to promote their own digi-
tal resources. CulturaItalia makes the digital resources interoperability possible,
through a cross-domain Application Profile (PICO AP: PICO is the acronym
for “Portale della Cultura Italiana On-line”), based on the Dublin Core Meta-
data Initiative technical guidelines. The Portal gives access to a rich “metadata”
collection, which gathers and organizes information arriving from the various
providers participating in the project. Users can discover different kinds of dig-
ital resources, describing the country’s extensive cultural heritage (museums,
photographs, libraries, archives, galleries, exhibitions, monuments, audio-visual
works, etc.). The pilot project dati.culturaitalia.it started in 2012 with the aim to
build up a Linked Open Data (LOD) Service that will progressively make avail-
able open datasets from the Web-portal. The application was designed by the
CulturaItalia team with the technical and scientific support of Scuola Normale
Superiore, and was developed by Meta s.r.l., to allow the resources aggregated
by CulturaItalia to be involved into large semantic networks after exposing,
sharing and connecting data according to LOD principles. A first release of this
service is available on-line since 2013 3 as a section, or sub-portal, of Cultur-
aItalia dedicated to LOD. It presently makes available as LOD the Thesaurus
PICO, adopted by the portal for facilitating the browsing of a variety of re-
sources in its domain, and a selection of metadata sets from the Portal. The
CulturaItalia team has chosen CIDOC-CRM, in the implementation of Erlan-
gen CRM/OWL, to foster the interoperability in the cultural heritage sector.
In the perspective of a future integration with the bibliographic heritage of the
Open Catalogue of the National Librarian System (OPAC SBN), managed by
ICCU, the Institute implemented, in 2014, a mapping activity, with the sup-
port of a team from VAST-LAB (PIN), to convert resources from OPAC SBN,
encoded in UNIMARC format, in FRBRoo, adopting the CIDOC-CRM model.
2 CulturaItalia Application Profile and Thesaurus
CulturaItalia manages a catalog - called Index - which gathers and indexes meta-
data provided by the partners. The original data remain on the Web-site of the
provider, to which the final user is redirected by CulturaItalia, through links,
thus allowing to retrieve the original and complete information. For example, in
the case of a photograph, in the CulturaItalia Index the preview image (thumb-
nail) is visible, together with some identifying data, and a link to the provider’s
website allows the user to visualize the photograph in its original format, accom-
panied by the complete information and services, in order to get the full benefit
of the item. The resources in the Index are classified on the basis of the PICO
Thesaurus, designed to manage and organize heterogeneous information, from
3
http://dati.culturaitalia.it/
45
Dati.CulturaItalia: a Use Case of Publishing Linked Open Data
different cataloging systems. Browsing the Index, the user consults the metadata
through a hierarchical classification of terms (facets). CulturaItalia is an “open”
system: it grows up and develops together with the continuous enrichment of its
metadata Index, through the metadata harvesting according to OAI-PMH, a pro-
tocol which allows the harvesting of metadata from content providers to one or
more harvesters, adding services as indexing system or automatic classification.
The Portal harvests metadata from different repositories and exports metadata
to other national and international portals and repositories. At present Cultur-
aItalia aggregates over 3 million metadata from 32 public and private partners
including thematic aggregators, such as Internet Culturale, the portal of Italian
Libraries, also created and managed by ICCU. Internet Culturale plays a key-
role in guiding the libraries in the production of standardized digital cultural
resources and metadata, according to the Italian standards. Metadata published
in Internet Culturale are automatically transferred to CulturaItalia, and then,
if the providing libraries agree, to Europeana.
Fig. 1. CulturaItalia aggregation workflow
All content from external data sources are integrated in CulturaItalia in
the form of metadata, thanks to the OAI-PMH harvesting protocol and pub-
lished in the portal using a specific Application Profile (PICO AP), based on
the international standard language, Dublin Core, that can describe, in a sin-
gle scheme, every type of cultural resource, both physical and digital. Following
DCMI recommendations, Scuola Normale Superiore di Pisa (SNS), which sup-
ports the ICCU working group engaged in the development of CulturaItalia,
defined an application profile which joins DC Element set, Qualified DC terms
and some further refinements and encoding schemes conceived for the applica-
46
Di Giorgio et al.
tion of CulturaItalia. The PICO AP combines in one metadata schema all DC
Elements, all DC Element Refinements and Encoding Schemes from the Quali-
fied DC, and other refinements and encoding schemes specifically conceived to
retrieve information pertaining to Italian culture. This Application Profile could
be further expanded for harvesting possible unexpected contents in the future,
by adding Refinements and Encoding Schemes that could be suitable for data re-
trieval. The PICO AP can be consulted at: http://purl.org/pico/picoap1.0.xml.
Schemas used for the PICO AP are published on a PURL, under the domain
PICO: http://purl.org/pico/1.1/pico.xsd and http://purl.org/pico/1.
1/picotype.xsd. One of the most relevant encoding schemes introduced in the
PICO AP is a Thesaurus specially conceived for the project itself, which compre-
hends hierarchically structured keywords indicating the topic of all the resources
included into CulturaItalia (PICO Thesaurus 4.3). This ontology is also used to
support the browsing into the Index of resources of Culturaitalia, therefore the
assignment of a value taken from the PICO Thesaurus is mandatory for each
metadata record. During the metadata generation, this assignment can be cre-
ated for a whole repository or for a whole set, while in some other cases it was
necessary to interpret a given value of the original database in order to create
a mapping into the Thesaurus. The PICO Thesaurus is organized in four main
categories: “Who” includes both people and corporate bodies; “What” compre-
hends tangible and intangible heritage, and all digital objects; “Where” covers
Italian places (from regions to towns and villages) and “When” includes a list
of chronological keywords associated to a sharp range of years. In order to be
more compliant with international best practices, it seemed useful to adopt a
SKOS format for the PICO Thesaurus. The SKOS format for Thesaurus PICO
has also been designed to be extended and/or integrated with different thesauri
pertaining to specific domains, managed by institutions that have a role in stan-
dardization, such as ICCD and ICCU, or to support multilingualism through
the mapping between different national KOS.
3 Mapping between PICO Application Profile and
CIDOC Conceptual Reference Model
PICO AP is a Dublin Core Application Profile. As already pointed out in the
literature related to mapping between Dublin Core and CIDOC-CRM, for every
value of the DC element “Type”, specifying a type of a described resource, it
must be specified a different mapping to a main entity of CIDOC CRM [3].
E.g.: IF DCMITipe = Image, THEN the described resource must be mapped
as CIDOC-CRM entity = E38 Image. Consequently, each record encoded ac-
cording to PICO AP will produce one main CIDOC-CRM corresponding entity,
and the mapping of all the other PICO AP elements describing the resource
will depend on the high-level mapping between the type of the resource and the
corresponding CIDOC-CRM entity. Within PICO AP, dc:type element is manda-
tory and repeatable (occurrence: min 1, max unbounded) [4]. As a condition, it
should always contain at least one value from DCMIType Vocabulary [5], (Col-
47
Dati.CulturaItalia: a Use Case of Publishing Linked Open Data
lection, Dataset, Event, Image, InteractiveResource, MovingImage, PhysicalOb-
ject, Service, Software, Sound, StillImage, Text) or from PICOType Vocabulary
[6] (CorporateBody, PhysicalPerson, Project). In the case that one PICO record
contains more than one DCMIType and/or PICOType term, the mapping doc-
ument (main DCMI/PICO Type term) specifies which must be considered the
main term, according to which the mapping must be defined. Those simulations
of complex mapping cases (between a PICO record containing more than one
DCMI/PICO Type term and one CIDOC-CRM corresponding element) are de-
scribed and are formulated on the basis of some real cases that can be found
among CulturaItalia metadata resources (more than on a logic basis). Moreover,
many of those cases are not real, and have been entered for completeness, just in
case that in the future similar cases could occur. On the basis of the digital re-
sources currently aggregated within CulturaItalia and of the PICO AP domain,
the term DCMI Type = Physical Object is mapped to CIDOC-CRM entity =
E22 Man Made Object (and not to E19 Physical Object). When DCMIType =
Collection, the record generally contains many other DCMI/PICO Type terms.
In all the cases, when “Collection” is present as a DCMIType, the PICO resource
will always be mapped to CIDOC-CRM “E78 Collection” entity. On the basis
of the mapping between the terms of DCMI and PICO Type Vocabularies, and
CIDOC CRM entities, CulturaItalia resources encoded according to PICO AP
can correspond to the following 12 CRM Entities:
E5 - - - - - - - Event
E22 - - - - - - Man-Made Object
E78 - - - - - - Collection
E28 - - - - - - Conceptual Object
E73 - - - - - - Information Object
E29 - - - - - - Design or Procedure
E33 - - - - - - Linguistic Object
E36 - - - - - - Visual Item
E38 - - - - - - Image
E39 - - - - - - Actor
E40 - - - - - - Legal Body
E21 - - - - - - Person
From this high-level mapping, based on the type of the described resource,
derive different mappings between the various types of PICO AP resources and
a corresponding CIDOC-CRM entity.
For a PICO resource with DCMIType= “PhysicalObject” (= crm:E22 Man
Made Object), the PICO AP element < pico : author > must be mapped as
shown in figure 2.
For a PICO resource with DCMIType= “StillImage” (= crm:E38 Image),
the same PICO AP element < pico : author > will be mapped as shown in
figure 3.
48
Di Giorgio et al.
Fig. 2. Mapping of the PICO AP element < pico : author > for a PICO resource with
DCMIType= “PhysicalObject”
Fig. 3. Mapping of the PICO AP element < pico : author > for a PICO resource with
DCMIType= “StillImage”
49
Dati.CulturaItalia: a Use Case of Publishing Linked Open Data
As CRM entities are ordered in a poly-hierarchy, and as the properties as-
sociated to each class are inherited by the subclasses, it is possible to group the
12 identified entities (and, consequently, the mapping to be implemented) into
4 main groups:
1. E18 Physical Thing contains the mappings for: E22 Man Made Object and
E78 Collection
2. E28 Conceptual Object contains the mappings for: E73 Information Object,
E29 Design or Procedure, E33 Linguistic Object, E36 Visual Item, E38 Image
3. E39 Actor contains the mappings for: E40 Legal Body, E21 Person
4. E5 Event
The detailed mapping containing four mapping tables (one for each of the
above-listed CRM main entities) is available on-line within the document: “Map-
ping between PICO Application profile and CIDOC Conceptual Reference Model”
[7].
Figure 4 presents the main elements of the mapping related to E18 Physical
Thing that contains the rules for E22 Man Made Object and E78 Collection.
Fig. 4. Mapping of E18 Physical Thing
4 Dati.CulturaItalia
The pilot project dati.culturaitalia.it started in 2012 to build up a Linked Open
Data (LOD) Service that will progressively make available open datasets from
the web-portal CulturaItalia. A first release of this service is available on-line
50
Di Giorgio et al.
since March 2013 [8] as a section of CulturaItalia dedicated to LOD. It presently
makes available as LOD the Thesaurus PICO and metadata aggregated by the
portal and licensed under CC0 1.0 - Universal Public Domain Dedication. These
are data coming from: Accademia di Santa Cecelia, ArtPast Project, Digibess,
ICCU, Internet Culturale, Michael Italia, Polo Museale Fiorentino, Regione
Marche and Anagrafe delle Biblioteche Italiane. More datasets will be increas-
ingly published as LOD, as soon as they will be delivered under CC0. Cultur-
aItalia platform extracts the datasets, encoded in XML PICO format, that have
been submitted by providers agreeing to take part of the pilot and to convert the
PICO metadata into CIDOC [9] standard, according to the mapping document
elaborated by M. E. Masci (Pisa, SNS). The mapping is implemented in an XML
stylesheet and the result is an RDF/XML representation of each data provider’s
metadata. Then the CulturaItalia repository allows for the semantic enrichment
with four types of reference resources (authority files):
– VIAF (Virtual International Authority File: www.viaf.org)
– GeoNames (www.geonames.org/)
– PICO Thesaurus in SKOS
– DCMI Type vocabulary
The SPARQL endpoint provides access to RDF metadata structured ac-
cording to the CIDOC - Conceptual Reference Model in the implementation
of Erlangen CRM/OWL. Data can be searched over three querying interfaces,
corresponding to three sections of dati.culturaitalia.it:
– Text search: here it is possible to perform free text searches over all triples
contained in dati.culturaitalia.it.
– SPARQL query: here you can try your hand at a SPARQL query. There are
also some examples of queries.
– iSPARQL query: here there is an even more complex querying interface for
advanced users.
Dati.culturaItalia.it exposes an OAI Provider that makes available XML or
RDF metadata structured according to different schemas:
– oai-dc (xml): OAI-PMH schema adopted by Open Archives Initiative Pro-
tocol for Metadata Harvesting
– pico (xml): PICO Application Profile, the CulturaItalia Application Profile
– edm (rdf): Europeana Data Model, adopted by the portal Europeana EDM
[10]
– cidoc (rdf): CIDOC - Conceptual Reference Model in the implementation of
Erlangen CRM / OWL
5 Mapping between UNIMARC Bibliographic Format /
SBN MARC and FRBRoo and next steps
ICCU is moving another step towards the Italian Linked Cultural Data Cloud
by starting the mapping study of data from the OPAC SBN (On line Public
51
Dati.CulturaItalia: a Use Case of Publishing Linked Open Data
Access Catalog of National Library Service) in UNIMARC format to the class
and the properties of FRBRoo, on the base of the model CIDOC CRM.
The collective catalogue of National Library Service provides access to 13.759.767
bibliographic records that contains:
– descriptions of documents acquired from SBN libraries starting from the ’90s
or since single libraries entered the SBN
– descriptions “book in hand” of documents of XVI - XX centuries
– descriptions obtained from catalogues on paper previous to 1990
In 2014 a working group formed by experts from ICCU and VAST-LAB
(PIN) was established with the objective to analyze and test the publication
of a subset of significant data in UNIMARC format as LOD according to the
document FRBR object-oriented definition and mapping to FRBR-ER (version
0.9). In particular, this activity focused on:
– analyzing and defining a basic methodology for creating Linked Open Data
from bibliographic archives according to the international standards and
cataloguing rules adopted by SBN;
– designing a schema with the conceptual description of how to relate SBN
bibliographic information in a semantic way. FRBRoo, an harmonization
between FRBR original conceptual model and CIDOC CRM, has been cho-
sen as the reference intellectual guide for this activity
– selecting a first set of bibliographic records to be exported from OPAC SBN
in UNIMARC format
– defining all the required namespaces and URI mechanisms to create mean-
ingful identifiers for the converted UNIMARC entities
Activities performed by the working team lead to the definition of a map-
ping document describing the conceptual mapping between UNIMARC fields
and FRBRoo entities and properties, with specific definition of mapping paths
for every possible combination or special use cases of UNIMARC encoded in-
formation available in the SBN archive. The selected records subset was used
for testing the conceptual coherence of the model in order to identify possible
conflicts and to fix co-reference and cross-reference issues that might have arose.
Specific exporting scripts have been developed to encode the UNIMARC bib-
liographic information in a standard RDF format, to transform it in a machine-
readable version using a formal language. Bibliographic information created in
this way was afterward enriched with entities coming from VIAF, GeoNames,
Linked Heritage, DBPedia, and other available online Linked Open Data re-
sources.
A web tool has also been created to store semantic records and to query and
retrieve relevant bibliographic data according with given semantic criteria. The
tool is composed of various modules efficiently interacting with each other and
based on open source technology. The modules include:
52
Di Giorgio et al.
– an online triple store based on Sesame to accommodate the RDF triples
created by the exporting framework and to manage the complex network of
relationships defined by means of it;
– a set of responsive web interfaces based on Ajax/JQuery technologies and
implementing the various features of semantic query and presentation of the
relevant results. A basic faceted system for a more efficient browsing of the
results was also implemented within the same interfaces.
The web tool also offers the possibility to download the full Linked Open
Data network of bibliographic information in an RDF compatible format for
local use. Further work on this topic will necessarily require a data clean-
ing phase for consolidating the legacy database in order to create a better
representation of its content during the mapping and conversion process.
Additional activities will concern the creation of a SPARQL end point for
advanced semantic queries, the improvement of the web interface to allow
connection of various libraries to the SBN index, to facilities retrieving and
FRBRoo encoded triples representing entities of interest (work, expression,
etc.) and the export of the same information in a standard Linked Open
Data format for them to be used by other bibliographic tools and in other
similar contexts. Data validation cycles to ensure the full compatibility of
the formats with the fundamental principles of Linked Open Data and Se-
mantic Web philosophy will be also performed, as well as multiple tests on
the internal coherence of the newly created dataset.
References
1. http://www.culturaitalia.it/
2. http://www.iccu.sbn.it/opencms/opencms/it/
3. Main references for the present mapping: M. Doerr, Mapping of the
Dublin Core Metadata Element Set to the CIDOC CRM, Technical Re-
port 274, ICS-FORTH, July 2000: http://www.cidoccrm.org/docs/dc_to_
crm_mapping.pdf; K. Kakali, M. Doerr, C. Papatheodorou, T. Stasinopoulou,
DC.type mapping to CIDOC/CRM, DELOS WP5-Task5.5, Department of
Archives and Library Science / Ionian University, 26/01/2007: http://www.
cidoc-crm.org/docs/WP5-T5_5-DC2CRMmapping-060728v0_2-final.doc ; I.
Lourdi, C. Papatheodorou, M. Doerr, Semantic Integration of Collection De-
scription. Combining CIDOC/CRM and Dublin Core Collections Applica-
tion Profile, D-Lib magazine, July/August 2009, vol. 15 n. 7/8, ISSN: 1082-
9873: http://www.dlib.org/dlib/july09/papatheodorou/07papatheodorou.
html; M. Doerr, Updated graphical representation of the harmonized EDM-
CRM-FRBRoo-DC-ORE models, September 2011: http://www.cidoc-crm.
org/docs/EDM-DC-ORE-CRM-FRBR_Integration_ORE_fix.ppt
4. PICOAP/dc:type: http://www.culturaitalia.it/opencms/export/sites/
culturaitalia/attachments/documenti/picoap/picoap1.0.xml#type
5. DCMI Type Vocabulary: http://dublincore.org/documents/
dcmi-type-vocabulary/
53
Dati.CulturaItalia: a Use Case of Publishing Linked Open Data
6. PICO Type Vocabulary: http://www.culturaitalia.it/opencms/export/
sites/culturaitalia/attachments/documenti/picoap/picoap1.0.xml#
PICOType
7. M. E. Masci, Mapping between PICO Application Profile and CIDOC Concep-
tual reference Model version 1.0, 2013-01-24
8. See at http://dati.culturaitalia.it
9. See the document at http://www.culturaitalia.it/opencms/export/sites/
culturaitalia/attachments/documenti/mapping/pico_cidoc/mapping_
PICO_CIDOC-CRM_ITA-ENG.pdf
10. See the document at http://www.culturaitalia.it/opencms/export/
sites/culturaitalia/attachments/documenti/mapping/pico_edm/
Mapping-PICO-EDM-2.0.pdf
54