The support of constructs in thesaurus tools from a Semantic Web perspective: Framework to assess standard conformance

15 p.Thesauri are conceptual tools useful to achieve semantic interoperability and reusability, which are relevant goals in the Semantic Web. Thesaurus standards establish, among other issues, the constructs that can appear in a thesaurus. The ISO 25964 standard for thesauri, which supersedes ISO 2788, is the evolution of the ISO thesauri standard to a conceptual approach closer to the Semantic Web. However, it appeared when SKOS -the W3C Recommendation- was already consolidated as the standard for KOS (Knowledge Organization System) representation in the Semantic Web, including thesauri. The evolution from ISO 2788 to ISO 25964, and the relationships between constructs in ISO 2788/ISO 25964 and SKOS, are studied in this paper. From the analysis of this comparison, a methodological framework, that focuses on the construct support, is proposed to evaluate the conformance quality of thesaurus management tools. Target readers are professionals in charge of thesauri edition. A Semantic Web perspective is taken to characterize the effect that using SKOS to represent thesauri can have on the results of the assessment. A proof of concept for the model’s feasibility was performed on two tools and the analysis of the results of this experimental validation is presented. The conclusions highlight the model’s suitability for assessing conformance to the standards concerning support for thesaurus constructs

Recent applications of Knowledge Organization Systems: introduction to a special issue

This special issue of the International Journal of Digital Libraries evolved from the 13th Networked Knowledge Organization Systems (NKOSs) workshop held at the joint Digital Libraries conference 2014 in London. The focus of the workshop was 'Mapping between Linked Data vocabularies of KOS' and ‘Meaningful Concept Display and Meaningful Visualization of KOS’. The issue presents six papers on the general theme on both conceptual aspects and technical implementation of NKOS. We dedicate this special issue to our long-term colleague and friend Johan De Smedt who died in June 2015 while we were editing the special issue. (author's abstract

Thesauri and Semantic Web: Discussion of the Evolution of Thesauri toward their Integration With the Semantic Web

15 p.Thesauri are Knowledge Organization Systems (KOS), that arise from the consensus of wide communities. They have been in use for many years and are regularly updated. Whereas in the past thesauri were designed for information professionals for indexing and searching, today there is a demand for conceptual vocabularies that enable inferencing by machines. The development of the Semantic Web has brought a new opportunity for thesauri, but thesauri also face the challenge of proving that they add value to it. The evolution of thesauri toward their integration with the Semantic Web is examined. Elements and structures in the thesaurus standard, ISO 25964, and SKOS (Simple Knowledge Organization System), the Semantic Web standard for representing KOS, are reviewed and compared. Moreover, the integrity rules of thesauri are contrasted with the axioms of SKOS. How SKOS has been applied to represent some real thesauri is taken into account. Three thesauri are chosen for this aim: AGROVOC, EuroVoc and the UNESCO Thesaurus. Based on the results of this comparison and analysis, the benefits that Semantic Web technologies offer to thesauri, how thesauri can contribute to the Semantic Web, and the challenges that would help to improve their integration with the Semantic Web are discussed.S

A Semantic Web methodological framework to evaluate the support of integrity in thesaurus tools

12 p.With the Semantic Web, thesauri recover a relevant role supporting semantic searches and other added-value services. Thesaurus standards define what constructs a thesaurus can have and the integrity rules it must comply with. Thesaurus editors can be helped in their work if thesaurus tools offer them support for integrity, warning when integrity rules are violated and/or helping them to correct these mistakes. The most recent thesaurus standard is ISO 25964, which supersedes ISO 2788, evolving towards concept-based thesauri, better aligned with the Semantic Web approach than the term-based thesauri of ISO 2788. However, the W3C recommendation for KOS (Knowledge Organization System) representation in the semantic web context is SKOS, which is in fact prior to ISO 25964. This paper focuses on thesaurus integrity and the evolution from ISO 2788 to ISO 25964. Its effect on integrity issues is analyzed. A methodological proposal for evaluating integrity support in thesaurus tools, arising from the results of this work, is presented. Its target audience is professionals in charge of thesaurus edition. Besides being adapted to the most recent thesaurus standard, ISO 25964, it also includes the comparison of ISO standards with SKOS. The paper is completed with the presentation of the results of applying it to three thesaurus tools

Representación de tesauros en SKOS: tendencias y desafíos para su integración en la Web Semántica

27(2), 13-20Los tesauros se han adaptado progresivamente a los entornos digitales demostrando su capacidad de integración con las tecnologías de la Web Semántica. No obstante, la convergencia de tesauros y Web Semántica no es tan directa como aparentemente pudiera parecer. Este trabajo analiza y contrasta los constructos y reglas de integridad de ISO 25964 y SKOS (Simple Knowledge Organization System). Se examinan igualmente las representaciones en SKOS de los tesauros AGROVOC, EuroVoc y Unesco con el fin de estudiar las soluciones llevadas a cabo. Por último, se abordan los retos percibidos, considerando particularmente la integración de los tesauros con los datos enlazados y el desarrollo de ontologías.S

On the composition of ISO 25964 hierarchical relations (BTG, BTP, BTI)

Knowledge organization systems (KOS) can use different types of hierarchical relations: broader generic (BTG), broader partitive (BTP), and broader instantial (BTI). The latest ISO standard on thesauri (ISO 25964) has formalized these relations in a corresponding OWL ontology (De Smedt et al., ISO 25964 part 1: thesauri for information retrieval: RDF/OWL vocabulary, extension of SKOS and SKOS-XL. http://purl.org/iso25964/skos-thes, 2013) and expressed them as properties: broaderGeneric, broaderPartitive, and broaderInstantial, respectively. These relations are used in actual thesaurus data. The compositionality of these types of hierarchical relations has not been investigated systematically yet. They all contribute to the general broader (BT) thesaurus relation and its transitive generalization broader transitive defined in the SKOS model for representing KOS. But specialized relationship types cannot be arbitrarily combined to produce new statements that have the same semantic precision, leading to cases where inference of broader transitive relationships may be misleading. We define Extended properties (BTGE, BTPE, BTIE) and analyze which compositions of the original “one-step” properties and the Extended properties are appropriate. This enables providing the new properties with valuable semantics usable, e.g., for fine-grained information retrieval purposes. In addition, we relax some of the constraints assigned to the ISO properties, namely the fact that hierarchical relationships apply to SKOS concepts only. This allows us to apply them to the Getty Art and Architecture Thesaurus (AAT), where they are also used for non-concepts (facets, hierarchy names, guide terms). In this paper, we present extensive examples derived from the recent publication of AAT as linked open data