From Athenawiki
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Introduction
Regarding the concern of terminology, Europeana requires that the collection digital descriptions of the museums are expressed with a SKOSified resource. Thus what is SKOS is here documented. Then, the Athena Format that the WP4 is currently setting up is detailed as a SKOS-compliant reference format for all the museums' terminologies.
SKOS Reference
SKOS Simple Knowledge Organization System - W3C Recommendation
Here is an abstract from the official documentation (section 1.2 SKOS overview):
The Simple Knowledge Organization System is a common data model for knowledge organization systems such as thesauri, classification schemes, subject heading systems and taxonomies. Using SKOS, a knowledge organization system can be expressed as machine-readable data. It can then be exchanged between computer applications and published in a machine-readable format in the Web.
The SKOS data model is formally defined in this specification as an OWL Full ontology. SKOS data are expressed as RDF triples, and may be encoded using any concrete RDF syntax (such as RDF/XML or Turtle). For more on the relationships between SKOS, RDF and OWL, see the next sub-section below.
The SKOS data model views a knowledge organization system as a concept scheme comprising a set of concepts. These SKOS concept schemes and SKOS concepts are identified by URIs, enabling anyone to refer to them unambiguously from any context, and making them a part of the World Wide Web. See Section 3. The skos:Concept Class for more on identifying and describing SKOS concepts, and Section 4. Concept Schemes for more on concept schemes.
SKOS concepts can be labeled with any number of lexical strings, such as "romantic love" or "れんあい", in any given natural language, such as English or Japanese (written here in hiragana). One of these labels in any given language can be indicated as the preferred label for that language, and the others as alternative labels. Labels may also be "hidden", which is useful where a knowledge organization system is being queried via a text index. See Section 5. Lexical Labels for more on the SKOS lexical labeling properties.
SKOS concepts can be assigned one or more notations, which are lexical codes used to uniquely identify the concept within the scope of a given concept scheme. While URIs are the preferred means of identifying SKOS concepts within computer systems, notations provide a bridge to other systems of identification already in use such as classification codes used in library catalogs. See Section 6. Notations for more on notations.
SKOS concepts can be documented with notes of various types. The SKOS data model provides a basic set of documentation properties, supporting scope notes, definitions and editorial notes, among others. This set is not meant to be exhaustive, but rather to provide a framework that can be extended by third parties to provide support for more specific types of note. See Section 7. Documentation Properties for more on notes.
SKOS concepts can be linked to other SKOS concepts via semantic relation properties. The SKOS data model provides support for hierarchical and associative links between SKOS concepts. Again, as with any part of the SKOS data model, these can be extended by third parties to provide support for more specific needs. See Section 8. Semantic Relations for more on linking SKOS concepts.
SKOS concepts can be grouped into collections, which can be labeled and/or ordered. This feature of the SKOS data model is intended to provide support for node labels within thesauri, and for situations where the ordering of a set of concepts is meaningful or provides some useful information. See Section 9. Concept Collections for more on collections.
SKOS concepts can be mapped to other SKOS concepts in different concept schemes. The SKOS data model provides support for four basic types of mapping link: hierarchical, associative, close equivalent and exact equivalent. See Section 10. Mapping Properties for more on mapping.
Finally, an optional extension to SKOS is defined in Appendix B. SKOS eXtension for Labels (SKOS-XL). SKOS-XL provides more support for identifying, describing and linking lexical entities.
SKOS Essentials
The core of the SKOS model relies on the following components: concepts, labels, relations, documentary notes, consceptSchemes and mapping facility. See the SKOS Primer for more details.
Concepts
The fundamental element of the SKOS vocabulary is the concept. Concepts are the units of thought —ideas, meanings, or (categories of) objects and events—which underlie many knowledge organization system. As such, concepts exist in the mind as abstract entities which are independent of the terms used to label them.
SKOS introduces the class skos:Concept, which allows implementors to assert that a given resource is a concept.
Labels
The first characterizations of concepts are the expressions that are used to refer to them in natural language: their labels. SKOS provides three properties to attach labels to conceptual resources: skos:prefLabel, skos:altLabel and skos:hiddenLabel.
Preferred Lexical Labels, skos:prefLabel
The skos:prefLabel property makes it possible to assign a preferred lexical label to a resource. Terms used as descriptors in indexing systems (thesauri, ...) will for instance be represented using this property
Alternative Lexical Labels, skos:altLabel
The skos:altLabel property makes it possible to assign an alternative lexical label to a concept. This is especially helpful when assigning labels beyond the one that is preferred for the concept, for instance when synonyms need to be represented.
Hidden Lexical Labels, skos:hiddenLabel
A hidden lexical label, represented by means of the skos:hiddenLabel property, is a lexical label for a resource, where a KOS designer would like that character string to be accessible to applications performing text-based indexing and search operations, but would not like that label to be visible otherwise. Hidden labels may for instance be used to include misspelled variants of other lexical labels.
Athena Format
Presentation
The Athena Format is the format that Athena Thesaurus is expressed with. This format is here proposed to the museums who want to map their own terminology with Athena Thesaurus. In this case, they have to use Athena Format in order to form their descriptions before mapping. As a SKOS-compliant format, Athena Format guarantees to the museums that their descriptions respect the relative Europeana requirement regarding SKOS.
Methodology
The Athena format is based on the SKOS Core and also inspired by the format defined for the MuseumVok vocabularies
Format
| Type | Field | Information | Comments |
|---|---|---|---|
| Concept | Concept | Class : Unit of thought, defined by a unique URI | Main element of the datamodel |
| Label | prefLabel | Term mostly used to express a concept | the attribute @xml:lang should be mandatory |
| Label | altLabel | Alternative term used to express a concept | the attribute @xml:lang should be mandatory |
| Label | hiddenLabel | Hidden term used to express a concept; HiddenLabel can be used to express mispelling or obsolete terms of the concept | the attribute @xml:lang should be mandatory |
| Relation (hierarchy) | broader | Broader concept | |
| Relation (hierarchy) | narrower | Narrower concept | |
| Relation (association) | related | Related concept | |
| Documentary notes | definition | ||
| Documentary notes | note | ||
| Documentary notes | scopeNote | ||
| Documentary notes | historyNote | ||
| Documentary notes | editorialNote | ||
| Documentary notes | example | ||
| Concept Schemes | ConceptScheme | Class | |
| Mapping | exactMatch | ||
| Mapping | broadMatch | ||
| Mapping | majorMatch | ||
| Mapping | minorMatch | ||
| Mapping | narrowMatch | ||
| Metadata | dc:source | Information on the source; property from Dublin Core | |
| Metadata | dc:creator | Information on the creator; property from Dublin Core | |
| Metadata | dc:created | Information on the source; property from Dublin Core | |
| Metadata | status | Status of the term (validated, draft, ...) |
SKOS: some examples
RAMEAU
RAMEAU
RAMEAU Concepts are described here according to the SKOS model to represent knowledge organization systems on the semantic web. Each concept comes with labelling information (either preferred or alternative labels) but also semantic relations to other concepts (broader, related) and various kind of notes.
EuroVoc
EuroVoc
The Eurovoc thesaurus is a multilingual, polythematic thesaurus focusing on the law and legislation of the European Union (EU). It is maintained by the Office for Official Publications of the European Communities and it is accesible in 21 official languages of the EU. Within the EU, the Eurovoc thesaurus is used in the Library of the European Parliament, the Publication Office as well as other information institutions of the EU. Moreover, the Eurovoc thesaurus is used in the libraries and documentation centers of national parliaments e.g. Spanish Senate) as well as other governmental and private organizations of member (and non-member) countries of the EU. Eurovoc exists in 22 official languages of the European Union (Bulgarian, Spanish, Czech, Danish, German, Estonian, Greek, English, French, Italian, Latvian, Lithuanian, Maltese, Hungarian, Dutch, Polish, Portuguese, Romanian, Slovak, Slovene, Finnish and Swedish) and one another language (Croatian).