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

KnowledgeOrganization Systems (KOS), in the formof classification systems, thesauri, lexical databases, ontologies, gazetteers, and taxonomies,more than ever play a crucial role in digital information management and applications generally. Carrying semantics in awell-controlled and documented way, Knowledge Organization Systems serve a variety of important functions such as: tools for representation and indexing of information and documents, knowledge-based support to information searchers, semantic road maps to domains and disciplines, communication tools that provide a conceptual framework, and a conceptual underpinning for knowledge-based systems. The European NKOS network has held a long-running series of annual workshops at the International Conference on Theory and Practice of Digital Libraries (TPDL), earlier known as the European Conference on Digital Libraries (ECDL). For details of North American and other NKOS network events, see http://nkos.slis.kent.edu/. Special issues on Networked Knowledge Organization Systems (NKOS) have been published in Journal of Digital Information in 2001 (https://journals.tdl.org/jodi/index.php/ jodi/issue/view/8) [1] and 2004 (https://journals.tdl.org/jodi/ index.php/jodi/issue/view/20) [2], theNewReviewofHypermedia and Multimedia in 2006 (http://www.tandfonline.