Modeling and Publishing of ControlledVocabularies for the UNESKOS ProjectJuan Antonio Pastor Sánchezpastor@um.es

University of Murcia (Spain)

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Structure of the webinar

■ Introduction

■ Semantic Web overview

■ Introduction to SKOS

■ Data model of the ISO-25964 standard

■ The ISO-THES ontology

■ Modelling of the Nomenclature and Thesaurus by appliying SKOS

■ Publishing platform.

■ Conclussions and future works

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Introduction: Context of the UNESKOS project

■ The use of controlled vocabularies (value vocabularies) to describe information resources is esential in Linked Open Data.

■ Controlled vocabularies are linkable, reusable and interoperable datasets.

■ SKOS ontology adopts an general approach, that can be applied to diverse types of Knowledge Organization Sistemas, allowing the mapping between vocabularies.

■ Nomenclature and Thesaurus of UNESCO are knowledge organization system widely used, whose reusability and interoperability can be very useful.

■ The main goal of the UNESKOS project is the application of SKOS and Linked Open Data principles to represent and publish both vocabularies.

■ The project has been developed by the Information Technologies Reseach Group of the University of Murcia in colaboration with the UNESCO Chair of Information Management in Organizations.

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Introduction: about nomenclature and thesaurus

UNESCO Thesaurus

● Used to query database of UNESCO and by other institution, terminological disambuation, development of other thesauri, teaching, etc.

● Conforms ISO-2788:1986 and ISO-5964:1985.

● Multilingual (English, French, Spanish and Russian), multidisciplinary and mono-hierarchical.

● Terminological thesaurus. Equivalence, hierarchical and associative relationships.

● Preferred and Non-preferred terms.

● The number of terms is different for each language:

Spanish and French: 8.664English: 7157Russian: 7013

● Seven major subject domains.

● Terms are grouped into 88 micro-thesauri.

● Avalaible on-line since 2000.

Proposed international standard nomenclature for fields of science and technology

● Clasiffication of information resources related with scientific research

● Created in 70's and proposed by UNESCO in 1988.

● Three level clasiffication:Fields → Disciplines → Sub-disciplines

● The categories of each leve have notations of two, four and six digits notations, i.e.:

22 Physics2202 Electromagnetism2202.05 Gamma rays

● Related categories:2202.09 Propagation of

electromagnetic waves(see 2105 Radiastronomy)

● Multilingual: English, French and Spanish.

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Architecture of the Semantic Web

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RDF Data model

subject objectpredicate

■ The main element of the RDF data model are statements about resources (documents, persons, physical objects, concepts, etc) by defining subject-predicate-object triples.

■ The object of a statement about a resource is another resource (object property) or data (data property).

■ Triples define connected graphs. Subject and Object are the graph nodes and predicates are the graph arcs. Both, nodes and arcs, are identified with URIs.

■ RDF Schema and OWL complements RDF and allow the creation of class taxonomies, as well as the range, domain and restrictions of properties, in order to define metadata schemas and web ontologies.

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RDF graph example

wikidata:Q463313

wikidata: http://www.wikidata.org/entity/

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RDF graph example

dbpedia:Romeo_and_Juliet

cwork:about

wikidata:Q463313

wikidata: http://www.wikidata.org/entity/cworks: http://www.bbc.co.uk/ontologies/creativework/dbpedia: http://dbpedia.org/resource/

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RDF graph example

dbpedia:Romeo_and_Juliet

“Romeoand Juliet”@en

dcterms:titlecwork:about

wikidata:Q463313

wikidata: http://www.wikidata.org/entity/cworks: http://www.bbc.co.uk/ontologies/creativework/dbpedia: http://dbpedia.org/resource/dcterms: http://purl.org/dc/terms/

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RDF graph example

dbpedia:Romeo_and_Juliet

“Romeoand Juliet”@en

dcterms:title

dcterms:creator

cwork:about

wikidata:Q463313

wikidata: http://www.wikidata.org/entity/cworks: http://www.bbc.co.uk/ontologies/creativework/dbpedia: http://dbpedia.org/resource/dcterms: http://purl.org/dc/terms/viaf: http://viaf.org/viaf/

viaf:96994048

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RDF graph example

dbpedia:Romeo_and_Juliet

“Romeoand Juliet”@en

dcterms:title

dcterms:creator

“William Shakespeare”@en

cwork:about

wikidata:Q463313

wikidata: http://www.wikidata.org/entity/cworks: http://www.bbc.co.uk/ontologies/creativework/dbpedia: http://dbpedia.org/resource/dcterms: http://purl.org/dc/terms/viaf: http://viaf.org/viaf/schema: http://schema.org/

viaf:96994048

schema:name

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RDF serializationR

DF

/XM

LJS

ON

-LD

<http://www.wikidata.org/entity/Q83186> dcterms:creator <https://viaf.org/viaf/96994048"> ; dcterms:title "Romeo and Juliet"@en .

@id:"http://www.wikidata.org/entity/Q83186","dcterms:creator":"https://viaf.org/viaf/96994048","dcterms:title":{"@language":"en","@value":"Romeo and Juliet"

<div resource="http://www.wikidata.org/entity/Q83186"> <h1 property="dcterms:title">Romeo and Juliet</h1> <p>Author:<span property="dcterms:creator resource="https://viaf.org/viaf/96994048"> William Shakespeare</span></p></div>

RD

Fa

Tu

rtle

<rdf:Description rdf:about="http://www.wikidata.org/entity/Q83186"> <dcterms:creator rdf:resource="https://viaf.org/viaf/96994048"/> <dcterms:title>Romeo and Juliet</dcterms:title></rdf:Description>

RDF graphs (serialization) are encoded using a format so that machines can exchange and process data.

Allow the use of XML technologies

(XSLT, XPath, XQuery, etc.)

Compact and light. Perfect for machines.

Designed for consumption by

JavaScript

Allows to insert RDF statements in HTML documents

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SPARQL

The RDF statements, that conform a dataset, can be stored into a text plain file. SPARQL allows to recover sentences that meet certain search conditions. SPARQL is for RDF like SQL is for the Relational Model.

select ?author WHERE { ?book dcterms:title "Romeo and Juliet" . ?book dcterms:creator ?author .}

select ?author WHERE { ?book dcterms:title "Romeo and Juliet" . ?bookdcterms:creator ?author . }

RDF/XMLTurtle

JSON-LDCSV

HTML Table...

A SPARQL Endpoint is a RESTful web service that accepts and processes SPARQL sentences

SPARQL queries retrieve statements stored into a RDF database named “Triplestore”

Results are retrieved into a format (serialization).

Who is the author of “Romeo and Juliet”?

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Linked Open Data = Data on the Web

■ Dereferenceable URIs must be used to identify and access objects and resources. An example would be an URL that identifies a resource and provides an Internet access address.

■ HTTP protocol must be used together Content Negotiation to provide data into a format required by the web client, either a web browser (HTML format) or other type of client that requires RDF/XML, Turtle, JSON-LD, etc.

■ Links to external resources (identified with URIs) should be included. This allows to discover new resources following the links.

■ Datasets must be avalaible for downloading in several RDF formats together a SPARQL Endpoint for selective data retrieval.

■ The dataset must have a use license for its open reusability.

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SKOS: Introduction

■ SKOS (Simple Knowledge Organization System) is an OWL ontology to represent knowledge organizations systems such as thesauri, classifications, subject headings, taxonomies, etc.

■ SKOS consider those systems as sets of concepts identified with URIs and grouped into a concept scheme.

■ SKOS concepts can be labeled with any number of lexical strings in any given natural language. One of these labels in any given language can be indicated as the preferred label for that language, and the others as alternative or hidden labels.

■ SKOS concepts can be linked to each other using hierarchical and associative semantic relations.

■ SKOS concepts can be documented with notes of various types: scope notes, definitions, editorial notes, etc.

■ SKOS concepts can be grouped into collections, which can be labeled and/or ordered.

■ SKOS concepts of different concept schemes can be mapped. SKOS provides four basic types of mapping link: hierarchical, associative, close equivalent and exact equivalent.

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SKOS: Classes

■ skos:ConceptSchemeA SKOS concept scheme can be viewed as an aggregation of one or more SKOS concepts. Concepts can be created and used as stand-alone entities. However, especially in indexing practice, concepts usually come in carefully compiled vocabularies, such as thesauri or classification schemes.

■ skos:ConceptThe fundamental element of the SKOS vocabulary is the concept that exist in the mind as abstract entities which are independent of the terms used to label them. A SKOS concept can be viewed as an idea or notion; a unit of thought.

■ skos:Collection skos:OrderedCollectionSKOS makes it possible to define meaningful groupings or "collections" of concepts. Collections are useful where a group of concepts shares something in common, and it is convenient to group them under a common label, or where some concepts can be placed in a meaningful order.

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SKOS: Labeling properties

■ skos:prefLabelAssign a preferred lexical label to a resource with an optional language tags. A resource can only have one preferred label per language tag. The preferred label of a concept may also be used to unambiguously represent this concept in a language within a KOS. Preferred labels are called “descriptors” in the thesaurus context.

■ skos:altLabelMakes it possible to assign alternative lexical labels, beyond the one that is preferred for the concept. Helpful to represent synonyms, near-synonyms, abbreviations and acronyms. Alternative labels are called “non-descriptor” in the thesaurus context.

■ skos:hiddenLabelA hidden lexical label for a resource is a character string accessible to applications, but not directly visible for users. Hidden labels may, for example, be used to include misspelled variants of other lexical labels. This way, the user will find a relevant concept if mis-spelled query match against a hiden label.

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SKOS: Labeling properties

“Brazil”@en

“FederativeRepublicof Brazil”@en

skos:prefLabel

skos:altLabel

skos:prefLabel

ex:Brasil

“Brasil”@es

“RepúblicaFederativade Brasil”@es

skos:altLabel

@prefix ex : <http://www.example.org/> .@prefix skos : <http://www.w3.org/2004/02/skos/core#> . @prefix rdf : <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

ex:Brasil rdfs:type skos:Concept ; skos:prefLabel "Brazil"@en ; skos:prefLabel "Brasil"@es ; skos:altLabel "Federative Republic of Brazil"@en ; skos:altLabel "República Federativa de Brasil"@es .

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SKOS: Semantic relations

Brasil AméricaSudamé-

rica

skos:broader skos:broader

skos:broader

Brasil AméricaSudamé-rica

skos:broaderTransitive skos:broaderTransitive

skos:broaderTransitive

■ skos:broader skos:narrowerAllow to assert that one concept is broader or narrower in meaning than another. These properties are each other's inverse. According to the SKOS data model, whenever a concept X is broader than another concept Y, then Y is a narrower concept of X.

■ skos:broaderTransitive skos:narrowerTransitiveThe properties skos:broader and skos:narrower, are not defined explicitly as transitive. This means that their semantics do not support inferences. For applications that require such semantics SKOS features skos:broaderTransitive and skos:narrowerTransitive.

■ skos:relatedEnables the representation of associative (non-hierarchical) links, such as relationship between one type of event and entities which typically participate in it. This property is symmetric: whenever a concept X is related with another concept Y, then Y is related with X. SKOS does not define this property as transitive.

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SKOS: Semantic relations example

ex:Brasil

@prefix ex : <http://www.example.org/> .@prefix skos : <http://www.w3.org/2004/02/skos/core#> . @prefix rdf : <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

ex:NAmerica rdfs:type skos:Concept ; skos:broader ex:America .ex:SAmerica rdfs:type skos:Concept ; skos:broader ex:America ; skos:narrower ex:Brazil .ex:America rdfs:type skos:Concept ; skos:narrower ex:NAmerica ; skos:narrower ex:SAmerica .ex:Brasil rdfs:type skos:Concept ; skos:broader ex:SAmerica .

skos:broader

skos:narrower

skos:broader

skos:narrower

skos:broader

skos:narrower

ex:SAmericaex:Americaex:NAmerica

Norteamérica América Sudamérica Brasil

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SKOS: Grouping properties

■ skos:inSchemeConcepts can be linked to one or more concept schemes using skos:inScheme.

■ skos:member skos:memberListTo indicate the concepts that are part of a collection are used skos:member (collections) and skos:memberList (ordered collections). Collections can be nested with these properties.

■ skos:hasTopConceptThe property is used to link a concept scheme to the SKOS concept(s) which are topmost in the hierarchical relations for that scheme.

■ skos:topConceptOfThis is the inverse property of skos:hasTopConcept. It indicates when a concept is at the top of the hierarchical structure of a concept scheme. A top concept should have no broader concepts.

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SKOS: Grouping properties (Top Concepts and skos:inScheme)

@prefix ex : <http://www.example.org/> .

ex:Tesauro rdfs:type skos:ConceptScheme ; skos:hasTopConcept ex:Africa, ex:America, ex:Antartida, ex:Asia, ex:Europa, ex:Oceania .

ex:Africa rdfs:type skos:Concept ; skos:inScheme ex:Thesaurus . skos:topConceptOf ex:Thesaurus

[...]

Geographical Areas, and countries

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skos:member

Countries byInternationalOrganizations

@prefix wikidata : <http://www.example.org/> .

ex:ColOrgInt rdfs:type skos:Collection ; skos:prefLabel "Countries by International Organizations"@es ; skos:member ex:ColOtan, ex:ColEurozona .

ex:ColOtan rdfs:type skos:Collection ; skos:prefLabel "NATO"@es ; skos:member ex:Belgica, ex:Canada, ex:Dinamarca, ex:EEUU, ex:Francia, ex:Islandia, ex:Italia, ex:Luxemburgo, ex:Noruega, ex:PaisesBajos, ex:Portugal, ex:UK, ex:Grecia, ex:Turquia, ex:Alemania, ex:España, ex:Hungria, ex:Polonia, ex:RepCheca, ex:Bulgaria, ex:Eslovaquia, ex:Eslovenia, ex:Estonia, ex:Letonia, ex:Lituania, ex:Rumania, ex:Croacia, ex:Albania.

ex:ColEurozona rdfs:type skos:Collection ; skos:prefLabel "Eurozone"@en ; skos:member ex:Austria, ex:Belgium, ex:Cyprus, ex:Estonia, ex:Finland, ex:France, ex:Germany, ex:Greece, ex:Ireland, ex:Italy, ex:Latvia, ex:Lithuania, ex:Luxembourg, ex:Malta, ex:Netherlands, ex:Portugal, ex:Slovakia, ex:Slovenia, ex:Spain .

Eurozone

ex:ColOrgInt ex:ColEurozonaex:ColOtan

NATO

ex:Austriaex:Bégica

ex:Chipreex:Estonia

ex:España

ex:Francia

ex:Alemania

ex:Grecia

ex: ...ex:Alemania

ex:EEUU

ex:Canada

ex:Bélgica

ex:España

skos:member skos:member skos:member

ex:...

SKOS: Grouping properties (Collections)

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SKOS: Documentation properties

■ skos:ScopeNoteSome, possibly partial, information about the intended meaning of a concept, especially as an indication of how the use of a concept is limited in indexing practice.

■ skos:definitionComplete explanation of the intended meaning of a concept.

■ skos:exampleSpecific examples which refer to a concept.

■ skos:editorialNoteSupplies information that is an aid to administrative housekeeping, such as reminders of editorial work still to be done.

■ skos:historyNoteDescribes significant changes to the meaning or the form of a concept.

■ skos:changeNoteDocuments fine-grained changes to a concept, for the purposes of administration and maintenance.

ex:frecMicroondas skos:scopeNote "Used for frequencies between 1GHz to 300Ghz"@en.

ex:documentation skos:definition "The process of storing and retrieving information"@en.

ex:orgCienciaCultura skos:example "Academies of science, general museums, world fairs"@en.

ex:folksonomia skos:editorialNote "Check spelling with Thomas Vander Wal"@en.

ex:unionEuropea skos:historyNote "Before European Community until the Treaty of Lisbon, 2009"@es.

ex:tomate skos:changeNote "Moved from under 'fruits' to under 'vegetables' by Horace Gray"@en.

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SKOS: Mapping properties

■ Every SKOS concept is unambiguously referenced with an URI in any SKOS application.

■ This is useful for mapping (alignment) links between SKOS concepts in different concept schemes, and their use for information retrieval tools that use several KOSs at the same time.

■ SKOS allows to specify how the meanings of two concepts from differente schemes can be compared.

■ skos:broadMatch skos:narrowMatchUsed to state a hierarchical mapping link between two concepts from different schemes.

■ skos:relatedMatchAllows to state an associative mapping link between two concepts from different schemes.

■ skos:closeMatchUsed to link two concepts sufficiently similar that can be used interchangeably in some information retrieval applications.

■ skos:exactMatchUsed to link two concepts that can be used interchangeably across a wide range of information retrieval applications. It is a transitive property.

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SKOS: Mapping example

skos:prefLabel"Aideéconomique"@fr

rameau:12148/

cb13318537z

"Economicassistance"@en

skos:prefLabel

skos:prefLabel

skos:altLabel

"Ayudaeconómica"@es

"CooperaciónEconómica"@es

lcsh:sh85040767

skos:closeMatchRepertoire d'autorité-matière encyclopédique et

alphabetique unifié

Library of Congress Subject Headings

Lista de Encabezamientos deMateria para las Bibliotecas Públicas

lem:LEM201001188

@Prefix lem: <http://id.sgcb.mcu.es/Autoridades/> .@Prefix rameau: <http://stitch.cs.vu.nl/vocabularies/rameau/ark:/> .@Prefix lcsh: <http://id.loc.gov/authorities/subjects/> .

rameau:12148/cb13318537z rdfs:type skos:Concept; skos:prefLabel "Aide économique"@fr .

lcsh:sh85040767 rdfs:type skos:Concept ; skos:prefLabel "Economic assistance"@en ; skos:closeMatch rameau:12148/cb13318537z .

lem:LEM201001188 rdfs:type skos:Concept ; skos:prefLabel "Ayuda económica"@es ; skos:altLabel "Cooperación económica"@es ; skos:closeMatch rameau:12148/cb13318537z, lcsh:sh85040767 .

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SKOS: SKOS-XL

■ Some applications require the creation of explicit links between the labels associated with concepts.

■ The SKOS lexical labeling properties (skos:preflabel, skos:altLabel, skos:hiddenLabel) cannot be the subject of an RDF statement, because they are just literal strings and not RDF resources. Therefore, and a direct relationship cannot be asserted between them.

■ SKOS eXtension for Labels (SKOS-XL) provides additional support for identifying, describing and linking lexical entities.

■ skosxl:LabelThis class allows labels to be treated as first-order RDF resources.

■ skosxl:literalFormThis property attach a single RDF literal to instances of skos:Label class.

■ skosxl:prefLabel skosxl:altLabel skosxl:hiddenLabelskosxl:Label instances can then be related to concepts using properties.

■ skos:labelRelationThis property allows that skosxl:Label instances can be linked together. It is possible use custom relationships by defining subproperties of skosxl:labelRelation.

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SKOS: SKOS-XL example

"USA"@en

ex:acronym

@Prefix rdf: <http://id.sgcb.mcu.es/Autoridades/> .@Prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .@Prefix skos: <http://www.w3.org/2004/02/skos/core#> .@Prefix skosxl: <http://www.w3.org/2008/05/skos-xl#> .@Prefix ex: <http://www.example.org/>

ex:C04221 rdf:type skos:Concept ; skosxl:prefLabel ex:lab04221_1 ; skosxl:altLabel ex:lab04221_2 .

ex:lab04221_1 rdf:type skosxl:Label ; skosxl:literalForm "USA"@en .ex:lab04221_2 rdf:type skosxl:Label ; skosxl:literalForm "United States of America"@en .

ex:acronym rdfs:subPropertyOf skosxl:labelRelation .ex:lab04221_1 ex:acronym ex:lab04221_2 .

"United Statesof America"@en

skosxl:prefLabel

skosxl:altLabel ex:lab04221_2

ex:lab04221_1

ex:C04221

skosxl:literalForm

skosxl:literalForm

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Norma ISO 25964: Thesauri and interoperability with other vocabularies

■ Update and superseed the previous ISO-5964:1985 and ISO-2788:1986.

■ Part 1: Thesauri for information retrieval (ISO 25964-1:2011).Part 2: Interoperability with other vocabularies (ISO 25964-2:2013).

■ Structure, elements, intra/interlinguistical equivalences, semantic relations, creation and management, formats, mapping and interoperability with other vocabularies, etc.

■ Defines an UML based data model and XML schema XML to represent thesauri.

■ ISO 25964 was published when SKOS had a wide deployment for creating controlled vocabularies datasets as Linked Open Data.

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ISO 25964: Content and context

ISO 25964-1Thesauri for

information retrieval

BS 8723-1Definitions,

symbols andabbreviations

BS 8723-2

ISO 2788

ISO 5964

25964-1 (secciones 5-12)Characteristics and relations of

monolingual thesauri and multilingual

BS 8723-3Other

vocabularies

BS 8723-4Interoperability

betweenvocabularies

BS 8723-5Exchange formatsand protocols forinteroperability

25964-2 (secciones 11-17)Interoperability with other vocabularies,

structural models and mapping.

25964-1 (secciones 13-18)Data model and Computer

Applications

ISO 25964-2Interoperability

with other vocabularies

25964-2 (secciones 5-10)Comparison of Controlled

vocabularies

Source: https://www.reseau-canope.fr/savoirscdi/uploads/pics/image4_01.png

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ISO 25964 UML data model

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ISO 25964 UML data model: Grouping structures

■ A thesaurus (Thesaurus) is formed by concepts (ThesaurusConcept) that can be grouped into groups (ConceptGroup) or sibling concepts lists (ThesaurusArray).

■ Both groups of concepts and terms arrays can be labeled and relate to each other hierarchically

■ It is possible to define different versions of a thesaurus. (VersionHistory).

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ISO 25964 UML data model: Semantic relations

■ The concepts can be related to each other by hierarchical, associative or higher level (top concepts) semantic relationships.

■ Hierarchical and associative relationships may specialize through the attribute “role” that allows to define different sub-types of semantic relationships.

■ Custom attributes may be defined for concepts, so that additional features can be set for them.

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ISO 25964 UML data model: Terminological equivalences

■ Preferred and Non-preferred terms can label a concept directly. Equivalences between terms can be defined.

■ Is possible to define compound equivalences for cases where a non-preferred term has more than one preferred term.

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ISO-THES ontology

http://pub.tenforce.com/schemas/iso25964/skos-thes

■ There are similarities between SKOS and the data model ISO 25964: conceptual and and terminological levels, grouping structures, identical documentation elements.

■ SKOS lacks native elements for compound equivalences, groups and arrays of concepts and customization of semantic relations.

■ ISO-THES ontology reuses SKOS and SKOS-XL and define new properties and classes to represent thesauri according to the data model established by the ISO 25964 standard.

■ Thesauri are represented with skos:ConceptScheme and concepts with skos:Concept. Two classes are defined, iso-thes:ConceptGroup and iso-thes:ThesaurusArray.

■ The SKOS labeling properties are reused for simple labeling of concepts and SKOS-XL is used to define simple or compound equivalences between labels and assign them to concepts.

■ The hierarchical relations (instantial, partitive and generic) are defined as sub-properties of skos:broader and skos:narrower.

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Application example of SKOS and ISO-THES

■ Thesaurus → skos:ConceptScheme

■ Knowledge field → iso-thes:ConceptGroup

■ Micro-thesaurus → iso-thes:ConceptGroup

■ Top concept → skos:Concept

■ Concept → skos:Concept

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@prefix ex : <http://www.example.org/> .@prefix skos : <http://www.w3.org/2004/02/skos/core#> . @prefix iso-thes: <http://purl.org/iso25964/skos-thes#> .@prefix rdf : <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

ex:UnescoThesaurus rdfs:type skos:ConceptScheme .

ex:areaCiencia rdfs:type skosthes:ConceptGroup ; iso-thes:microThesaurusOf ex:UnescoThesaurus iso-thes:subGroup ex:microthesBiology .

ex:microthesBiology rdfs:type iso-thes:ConceptGroup ; iso-thes:superGroup ex:fieldCiencia .

→UNESCO THESAURUS

SCIENCE(field)

BIOLOGY(micro-thesaurus)

→

Application example of SKOS and ISO-THES

■ A classic scenario for the application of ISO-THES ontology is the modeling of micro-thesauri and fields or knowledge areas (Eurovoc Thesaurus UNESCO):

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Terminological equivalence in ISO-THES

@prefix ex : <http://www.example.org/> .@prefix skos : <http://www.w3.org/2004/02/skos/core#> . @prefix iso-thes: <http://purl.org/iso25964/skos-thes#> .@prefix rdf : <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .@Prefix skosxl: <http://www.w3.org/2008/05/skos-xl#> .

ex:coal rdfs:type iso-thes:PreferredTerm ; skosxl:literalForm "Coal"@en ; iso-thes:plusUFTerm ex:coalMining .

ex:mining rdfs:type iso-thes:PreferredTerm ; skosxl:literalForm "Mining"@en ; iso-thes:plusUFTerm ex:coalMining .

ex:coalMining rdfs:type iso-thes:SplitPreferredTerm ; skosxl:literalForm "Coal Mining"@en ; iso-thes:plusUseTerm ex:coal ; iso-thes:plusUseTerm ex:mineria .

Coal MiningUSE Coal+ Mining

CoalUP+ Coal Mining

MiningUP+ Coal Mining→

■ ISO 25964 allows to compound complex concepts by combining terms. The ISO-THES ontology reuses SKOS-XL to define classes and properties that develop this functionality.

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Modeling of the Nomenclature

■ The nomenclature can be represented perfectly with SKOS.

■ One concept scheme (skos:ConceptScheme) to represent the vocabulary.

■ One concept (skos:Concept) to represent every category.

■ One preferred label (skos:prefLabel) per language for every concept.

■ Hierarchical relationships represented with skos:broader and skos:narrower.

■ Related categories represented with skos:related.

■ Digits represented with skos:notation

■ There are 201 concepts that share the same preferred label in one of the languages of these cases 192 correspond to labels containing the literal "Other (specify)".

1105 Metodology 610701 Metodologíy110499 Other (specify) 332999 Other (specify)

This is consistent with the SKOS recommendation, but is a problem in the search processes of concepts and for evaluating the quality of vocabulary.

May 18, 2016 40 / 64

Modeling of the Nomenclature

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix skos: <http://www.w3.org/2004/02/skos/core#> . <http://skos.um.es/unesco6/2105> rdf:type skos:Concept ; skos:prefLabel "Radio-astronomie"@fr ; skos:prefLabel "Radioastronomy"@en ; skos:prefLabel "Radioastronomía "@es ; skos:inScheme <http://skos.um.es/unesco6/00> ; skos:narrower <http://skos.um.es/unesco6/210599> ; skos:narrower <http://skos.um.es/unesco6/210502>; skos:narrower <http://skos.um.es/unesco6/210501> ; skos:notation "2105" ; skos:broader <http://skos.um.es/unesco6/21> ; skos:related <http://skos.um.es/unesco6/220209> .

■ 20820 triples■ 2504 concepts (skos:Concept)■ 1 concept scheme (skos:ConceptScheme)■ 7315 preferred labels (skos:prefLabel)■ 3 languages (Spanish, English, French)■ 3 Dublin Core title (dc:title)■ 2480 narrower relations (skos:narrower)■ 2480 broader relations (skos:broader)■ 780 associative relations (skos:related)

http://skos.um.es/unesco6

May 18, 2016 41 / 64

Modelling of the Thesaurus

■ The main difficulty of modeling is the representation of the structure of the 7 knowledge fields and 88 micro-thesauri.

■ For the first version four options for modeling, were analyzed.

May 18, 2016 42 / 64

Modelling of the Thesaurus → Discarded options

Represent the Thesaurus, knowledge field and micro-thesauri as concept schemes and hierarchize them with skos:inScheme

<S> rdf:type skos:ConceptScheme<S1> rdf:type skos:ConceptScheme<S105> rdf:type skos:ConceptScheme<S1> skos:inScheme <S><S105> skos:inScheme <S1>O

PC

IÓN

A skos: Concept Scheme is used in common practice for represent the entire vocabulary. Micro-thesauri are subsets of the vocabulary.

Define properties with different semantics of skos:inScheme to define hierarchies of concept schemes: ex:subScheme and ex:subSchemeOf.

<S> rdf:type skos:ConceptScheme<S1> rdf:type skos:ConceptScheme<S105> rdf:type skos:ConceptScheme<S> ex:subScheme <S1><S1> ex:subScheme <S105><S1> ex:subSchemeOf <S><S105> ex:subSchemeOf <S1>

OP

CIÓ

N B The UNESCO team avoided

define an ad hoc vocabulary and used only native classes and properties offered by SKOS.

Application of the correspondences between ISO 25964 and SKOS / SKOS-XL (ISO-THES).

<S> rdf:type skos:ConceptScheme<S1> rdf:type iso-thes:ConceptGroup<S105> rdf:type iso-thes:ConceptGroup<S1> iso-thes:microThesaurusOf <S><S1> iso-thes:subGroup <S105><S105> iso-thes:subGroupOf <S1>O

PC

IÓN

C Proposal under development, which did not even have a namespace to reference the vocabulary elements.

<S> UNESCO Thesaurus<S1> Knowledge field "1 Education"<S105> Micro-thesaurus "1.05 Educational sciences and enviroment"

May 18, 2016 43 / 64

Modelling of the Thesaurus → Implemented option (1st version)

■ Thesaurus is represent as a concept scheme (skos:ConceptScheme).

■ Knowledge fields and micro-thesauri are represented as collections (skos:Collection).

■ Field are related to concept scheme through skos:inScheme.

■ Micro-thesauri are related with knowledge fields through skos:member.

■ Concepts are related with concept scheme through skos:inScheme.

■ Concepts are related with micro-thesauri through skos:member.

■ Descriptor terms are represented with skos:prefLabel.

■ Non-descriptors are represented with skos:altLabel.

■ Hierarchical relations are defined with skos:broader and skos:narrower.

■ Associative relations are defined with skos:related.

■ Other complementary labeling properties: dcterms:title y rdfs:label (thesaurus, fields and micro-thesauris labeling)

■ Detected some inconsistencies:■ Russian non-descriptors without equivalent descriptors and hierarchically interrelated.

■ Four terms without associated micro-thesaurus.

■ Communicated to managers of the UNESCO thesaurus to solve errors using the solutions adopted by UNESKOS.

May 18, 2016 44 / 64

Modelado del Tesauro → Opción implementada (1ª versión)

<S> rdf:type skos:ConceptScheme<S1> rdf:type skos:Collection<S105> rdf:type skos:Collection<S1> skos:inScheme <S><S1> skos:member <S105><C> rdf:type skos:Concept<S105> skos:member <C>

■ 78680 triples■ 4 languages (English, Spanish, French and Russian)■ 1 concept scheme (skos:ConceptScheme)■ 96 collections (skos:Collection)■ 4408 concepts (skos:Concept)■ 17980 preferred label (skos:prefLabel)■ 13868 alternative label (skos:altLabel)■ 4244 narrower relations (skos:narrower)■ 4244 broader relations (skos:broader)■ 12196 associative relations (skos:related)■ 583 top concepts (skos:hasTopConcept,

skos:topConceptOf)

http://skos.um.es/unescothes

May 18, 2016 45 / 64

NO

YES

NO

YES

NO

YES

YES

NO

Non-standardform

NO

One way

NO

NO

NO

Limitations of SKOS and ISO-THES

Represent micro-thesauri or otherconcept scheme subdivisions

Compound labels ofconcepts

Link from a concept toward the colection to which belong

Explicit definition of collections of hierarchies

Link from the concept scheme toward the colections that contains

Link from a colection toward the concept scheme to which belong

Explicit definition of concept as access point of a collection

Aspect analized SKOS ISO-THES

■ Both SKOS and ISO-TES, have important limitations to RDF-consumption by applications based on data discovery from relationships between resources.

May 18, 2016 46 / 64

Implications of the limitations of SKOS and ISO-THES

■ Limitations of SKOS in modeling the UNESKOS vocabularies:

■ SKOS is adequate to represent the Nomenclature ...

■ … but is limited to represent the Thesaurus, since there is not an unique and immediate solution for modeling the knowledge fields and micro-thesauri.

■ Limitations of SKOS and ISO-THES for Linked Open Data

■ It is impossible to directly represent links from a concept or collection to the collection to which they belong.

■ It is impossible to identify the micro-thesaurus to which a concept belong following the links from the concepts to other resources.

■ It is impossible to directly represent the top concepts of micro-thesauri and it is necessary the use of SPARQL.

■ The inclusion of additional RDF statements outside the described resource (Concise Bounded Symmetric Description) is not a standard and efficient technique.

■ The proposal of ISO-THES not solve these problems.

May 18, 2016 47 / 64

Modeling approaches for the second version of the Thesaurus

■ The first versions of the UNESKOS vocabularies were completed in December 2012.

■ In 2015 it began to develop a second version under the following principles:

■ Update the contents of both vocabularies.

■ Fix errors due to serialization errors of the script for the creation of RDF/XML and Turtle files.

■ Apply ISO-THES to represent the knowledge areas and micro-thesauri of the UNESCO Thesaurus.

■ Development of a small vocabulary that solves the limitations of SKOS/ISO-THES regarding the publication of Linked Open Data. Native classes of SKOS / ISO-THES are used along with ad-hoc complementary properties.

■ Improve the HTML interface:■ Loading speed of pages.■ Web accesibility.■ Responsive design.

■ Improve the system search by modifying the conversion of user queries to SPARQL queries.

■ Two new browsing tools:■ Hierarchical browsing.■ Alfabetical browsing.

May 18, 2016 48 / 64

UNESKOS Vocabulary

uneskos:contains <http://purl.org/umu/uneskos#contains>Links a concept scheme with any SKOS element SKOS.Inverse of: skos:inScheme Domain: skos:ConceptScheme

uneskos:hasMainConcept <http://purl.org/umu/uneskos#hasMainConcept>Identifies from a collection those concepts that are access points of a collection.Inverse of: uneskos:mainConceptOf Domain: skos:Collection Range: skos:Concept

uneskos:hasMicroThesaurus <http://purl.org/umu/uneskos#hasMicroThesaurus>Identifies from a concept scheme the concept groups that belong to the concept scheme.Inverse of: iso-thes:microThesaurusOf / Domain: skos:ConceptScheme / Range: iso-thes:ConceptGroup

uneskos:mainConceptOf <http://purl.org/umu/uneskos#mainConceptOf>Identifies from a concept those collections for which is an access point.Inverse of: uneskos:hasMainConcept Domain: skos:Concept Range: skos:Collection

uneskos:memberOf <http://purl.org/umu/uneskos#memberOf>Idesde un concepto identifica aquellas colecciones a las que pertenece.Inverse of: skos:member Domain: skos:Concept Range: skos:Collection

Namespace and RDF vocabulary: http://purl.org/umu/uneskos

Especification: http://skos.um.es/TR/uneskos

May 18, 2016 49 / 64

Application of SKOS, ISO-THES and UNESKOS Vocabulary

● Thesaurus → skos:ConceptScheme

● Knowledge field → iso-thes:ConceptGroup

● Micro-thesaurus → iso-thes:ConceptGroup

● Top concept → skos:Concept

● Concept → skos:ConceptSKOS / ISO-THES

PropertiesUNESKOSProperties

May 18, 2016 50 / 64

Platform for Linked Open Data publishing

■ The publishing platform is self-developed with PHP along MYSQL and ARC2 library functions for serialization, triplestore, SPARQL Endpoint, etc. The application retrieves data directly from triplestore.

■ Dereferencable URINamespaces: <http://skos.um.es/unesco6> <http://skos.um.es/unescothes> generic URIs to identify the resource and specific URIs for every format:<http://skos.um.es/unescothres/C04305> → generic URI<http://skos.um.es/unescothes/C04305/rdfxml> → URI for RDF/XML format.

■ Content negotiationWhen a web client request a generic URI the server returns the status code “303 See others” along with the specific URI of the requested format.

■ Formats and open standardsRDFa 1.1 for HTML version, RDF/XML, Turtle, JSON y JSON-LD

■ Availability of datasetsThe datasets of both vocabularies are avalaible in RDF/XML and Turtle files.

■ SPARQL EndpointAvailability of a SPARQL Endpoint (recommendation SPARQL 2008).

■ Datasets licenseCreative Commons BY-NC-SA 3.0 license, compatible with generic copyright of UNESCO

May 18, 2016 51 / 64

System Architecture

HTML + RDFaRDF

RDF/XML, Turtle,JSON, etc...

SPARQLEndpoint

HTMLClient

RDFClient

SPARQLClient

MySQL

HTTP Server (Apache)

PHP Application + ARC2

Contentnegotiation

rules

Web Server

May 18, 2016 52 / 64

Content negotiation

Example of request / response with content negotiation

GET [http://skos.um.es/unescothes/C00019] Accept: text/html

HTMLClient

Server303 See OtherLocation:

[http://skos.um.es/unescothes/C00019/html]

Server

200 OK

<html>

GET [http://skos.um.es/unescothes/C00019/rdf] Accept: application/rdf+xml

RDFClient

Server200 OK

<rdf>

Example of request / response

HTMLClient

May 18, 2016 53 / 64

...<ul rel="skos:narrower"> <li resource="http://skos.um.es/unescothes/C03519"><strong>NT</strong> <a href="http://skos.um.es/unescothes/C03519/html">School mapping</a> </li></ul>...

Semantic Markup with RDFa

...<ul rel="skos:related"> <li resource="http://skos.um.es/unescothes/C01269"><strong>RT</strong> <a href="http://skos.um.es/unescothes/C01269/html">Educational programmes</a></li></ul>...

...<div id="node" about="http://skos.um.es/unescothes/C01270" typeof="skos:Concept"> <h2><span property="skos:prefLabel" xml:lang="en">Educational projects</span></h2>...

...<li><strong property="skos:prefLabel" xml:lang="es"> Proyecto de educación</strong> (Término español)</li><li><strong property="skos:prefLabel" xml:lang="fr">Projet d'éducation</strong> (Terme français)</li><li><strong property="skos:prefLabel" xml:lang="ru">Образовательные проекты</strong> (Русский термин)</li>...

...<a href="http://skos.um.es/unescothes/COL115" rel="uneskos:memberOf uneskos:mainConceptOf">1.15 Educational planning</a>...

May 18, 2016 54 / 64

Semantic Markup with RDFa

@prefix skos: <http://www.w3.org/2004/02/skos/core#> .@prefix unescothes: <http://skos.um.es/unescothes/> .@prefix uneskos: <http://purl.org/umu/uneskos#> .

unescothes:C01270 a skos:Concept; uneskos:mainConceptOf unescothes:COL115; uneskos:memberOf unescothes:COL115; skos:altLabel "Proyecto educativo"@es; skos:narrower unescothes:C03519; skos:prefLabel "Educational projects"@en, "Projet d'éducation"@fr, "Proyecto de educación"@es, "Образовательные проекты"@ru; skos:related unescothes:C01269 .

https://www.w3.org/2012/pyRdfa/

May 18, 2016 55 / 64

Concept search by label

■ The system performs multilingual searches in the preferred and alternative labels (vocabularies does not use hidden tags).

■ The search is case insensitive and flexible with respect to the use of special characters, accented vowels, etc.

■ Matches with alternative labels are shown with a forwarding links with the preferred label of the concept.

■ The results page displays additional information such as the URL of the concept, preferred labels in other languages and micro-thesaurus to which the concept belongs.

May 18, 2016 56 / 64

Alphabetical and hierarchical presentations and breadcrumbs

■ The hierarchical representation shows the areas, microthesauri with corresponding concepts with drop-down lists.

■ The alphabetical list includes both preferred and alternative labels.

■ A breadcrumbs navigation system is included in each concept displaying the path within the hierarchical structure of micro-thesaurus to reach the concept.

May 18, 2016 57 / 64

SPARQL Endpoint

■ For both vocabularies it is available a fully functional SPARQL endpoint.

■ This service allows SPARQL queries and retrieve the results in various formats.

■ Because ARC2 only implements SPARQL 1.0, the SPARQL Endpoint does not apply the new recommendation of the W3C SPARQL 1.1

http://skos.um.es/sparql

May 18, 2016 58 / 64

Conforms to W3C standards

■ W3C standards have been respected, especially XHTML + RDFa marking 1.1 and using CSS3 style sheets.

■ This ensures compatibility with any browser that includes such standards.

http://validator.w3.org/

https://jigsaw.w3.org/css-validator/

May 18, 2016 59 / 64

Web accessibility

■ The website design follows the guidelines of WCAG 2.0

■ Javascript not be used practically.

■ Visual effects and transitions were generated with XHTML and CSS3, being compatible with all web browsers for desktop and mobile devices.

■ The HTML code generated by the application is simple and efficient, facilitating the fluidity of use from the web browser.

http://examinator.ws

May 18, 2016 60 / 64

Responsive design

■ The interface is adapted to any type of device with a responsive design that adapts font sizes, layout and collapses the navigation menu into an icon in the top left.

May 18, 2016 61 / 64

Design optimized for fast loading

https://developers.google.com/speed/pagespeed/insights/

May 18, 2016 62 / 64

Conclusions and Future Work

■ ISO-THES is still in development but has enough elements to model thesauri according to ISO 25964.

■ SKOS has limitations to represent composite mapping between concepts in different vocabularies. The data model of ISO 25964 does not explicitly provide for such relationships.

■ SKOS offers several ways to represent the same vocabulary. It would be interesting to define a set of best practices and an analysis of alternatives to model certain elements of different types of vocabulary.

■ The UNESCO project is currently focused on automatic mapping vocabularies.

■ The platform is migrating to an environment consisting of Apache Jena Fuseki (allows SPARQL 1.1. for the SPARQL Endpoint) and Apache Solr.

May 18, 2016 63 / 64

Correspondence between ISO 25964 and SKOS/SKOS XL Models. ‐http://www.niso.org/schemas/iso25964/correspondencesSKOS/

Data on the Web Best Practices. W3C Working Draft 25 June 2015. http://www.w3.org/TR/dwbp/

ISO. ISO 25964-1:2011. Thesauri and interoperability with other vocabularies. Part 1: Thesauri for information retrieval. Geneva: International Organization for Standarization, 2011.

ISO. ISO/DIS 25964-1:2013 Thesauri and interoperability with other vocabularies. Part 2: Interoperability with other vocabularies. Geneva: International Organization for Standarization, 2013.

ISO 25964 SKOS extension (iso-thes). http://pub.tenforce.com/schemas/iso25964/skos-thes/

Mader, C. & Suominen, O. (2014). Assessing and Improving the Quality of SKOS Vocabularies. Journal on Data Semantics, 3(1), 47-73. http://prints.cs.univie.ac.at/3707/1/skosquality.pdf

Pastor-Sánchez, J.A.; Martínez-Méndez, F.J.; López-Carreño, R.; Rodríguez-Muñoz, J.V. (2013). UNESKOS: publicación como Linked Open Data de la Nomenclatura Internacional de Ciencia y Tecnología y del Tesauro UNESCO. I CONGRESSO ISKO ESPANHA E PORTUGAL/XI CONGRESSO ISKO ESPANHA, 2013. http://eprints.rclis.org/24272

SKOS Simple Knowledge Organization System Primer. W3C Working Group Note 18 August 2009. http://www.w3.org/TR/skos-primer/

SKOS Simple Knowledge Organization System Reference. W3C Recommendation 18 August 2009. http://www.w3.org/TR/skos-reference/

References

Thank you very much for your attentionQuestions?Suggestions?Criticisms?Congratulations?