Knowledge Organization System (KOS)

Marcia Lei Zeng. Knowledge Organization System (KOS). Knowledge Organization[J]. 2008(35): 160-182

This paper is a review about different types of KOS and their applications.

1. Overview of types of Knowledge Organization Systems
The Class of KOS has four major groups
(1) Term List: List (pick list), Dictionaries, Glossaries, Synonym Rings
(2) Metadata-like Models: Authority Files, Directories, Gazetteers
(3) Classification and Categorization: Subject Headings, Categorization Schemes, Taxonomies, Classification Schemes
(4) Relationship Models: Thesauri, Semantic Networks, Ontology

2. Structure and characteristics of common KOS
(1) Structures that focus on eliminating ambiguity (eg. Using lists for browsing and searching).

(2) Structures that focus on controlling synonyms or equivalents (eg. Using authority files,  gazetteers or synonym rings).

(3) Structure that focus on making explicit semantic relationships.

a. Hierarchical Relationships: each class may have parents, siblings and children. There are three conditions of this relationship, including generic relationships, instance relationships, and whole-part relationships (eg. Using taxonomy).
b. Associative Relationships: cover relationships that are neither equivalent nor hierarchical, like cause-effect, process- agent, action-product, and so on (eg. Using thesauri).

Visualization applications for semantic relationships:
Visual Concept Explorer (

(4) Structure that present both semantic relationships and properties
eg. Using ontology to show relations of objects as well as properties, rules and so on

Visualization applications for ontology:
Foundational Model Explorer (

3. Conclusion
Future Trend: Machine-understandable, not just machine-readable

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