Il Semantic web nelle biblioteche e nel patrimonio culturale

Oreste Signore, <>

Summer School LDA
Libraries in the digital age: linked data technologies for a global knowledge sharing
Pula (Cagliari), 29 agosto - 1° settembre 2016

Documento pdf:

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Dublin Core in RDF

Il text retrieval

Naturalis Historia - frontespizio
Plinio il Vecchio-immagine

In principio fu lo scriptorium…

miniatura di un amanuense

stat rosa pristina nomine, nomina nuda tenemus

…poi venne Gutenberg…

Gutenberg - la Bibbia


…e infine i calcolatori

Dublin Core Metadata Initiative

Il portale Dublin Core

Dublin Core: la grammatica


Dublin Core in RDF


Dublin Core: due esempi


Thesaurus vs ontology

(from: Fausto Giunchiglia and Ilya Zaihrayeu: LIGHTWEIGHT ONTOLOGIES - October 2007 - Technical Report DIT-07-071)

Beware of false friends!

Faceted thesauri

Faceted thesauri are similar in many ways to faceted classification systems. There are potentially differences in the intended use, as discussed in Sect. 4. However there is scope for using both in combination. Faceted thesauri can be used in both pre- and post-coordinated systems and can underpin both search and browsing applications.
Faceted thesauri belong to the family of KOS, which has been used by the library community in modelling for purposes associated with information retrieval applications. They provide a semantic structure at a suitable granularity for the general problem of search and retrieval. In such applications, where a fuzzy notion of “aboutness“ is the basis for indexing or classifying a document, as opposed to an assertion of fact, the lightweight semantics of faceted thesauri and related KOS may be more suited than the formal semantics provided by AI ontologies, designed for precisely modelling the objects of interest in a domain. The SKOS standard representation, combined with other developments in standard identifiers and service protocols, now affords the combination of formal syntax and informal semantics, in Semantic Web applications and online applications generally. This offers a cost effective approach for annotation, search and browsing oriented applications that don't require first order logic.

(Douglas Tudhope & Ceri Binding: Faceted Thesauri, Axiomathes (2008) 18:211–222 DOI DOI 10.1007/s10516-008-9031-6)

Limitations of existing KOS

Lack of conceptual abstraction
thesauri and other traditional KOS are collections of terms (generic or domain-specific), ordered in a polyhierarchic lattice structure or a monohierarchic tree structure and interlinked with some very broad and basic relationships. The distinction between a concept (meaning) and its lexicalizations (words) is not made consistently, if at all, in such a system, and as such it does not reflect the ways humans understand the world in terms of meaning and language
Limited semantic coverage
most thesauri do not differentiate concepts into types or categories (such as living organism, substance, or process) and have a very limited set of relationships between concepts, distinguishing only between hierarchical relationships, i.e. NT/BT, and associative relationships, i.e. RT. These very rudimentary relationships are not powerful enough to guide a user in meaningful information discovery on the Web or to support inference. They do not reflect the conceptual relationships that people know and that can be used by a system to suggest concepts for expanding the query or making it more specific.
Lack of consistency
since the relationships in thesauri lack precise semantics, they are applied inconsistently, both creating ambiguity in the interpretation of the relationships and resulting in an overall internal semantic structure that is irregular and unpredictable. Many of the NT/BT hierarchical relationships could, for example, be resolved to the non-hierarchical RT relationship, and vice versa
Limited automated processing
traditionally thesauri were designed for indexing and query formulation by people and not for automated processing. The ambiguous semantics that characterizes many thesauri makes them unsuitable for automated processing

Brian Vickery: A note on knowledge organisation, [web] [local]


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