Høgskolen i Oslo Topic maps, a technology for knowledge organisation Presentation at ELAG 2004 Nils Pharo

Schedule l Topic maps is a standard for organising digital content l ISO certified in 2002 (ISO 13250) l Used for structuring web sites, knowledge management…

The basic elements of topic maps Topic maps consist of l Topics l Associations l Occurrences i.e. the TAO of topic maps (Pepper, 2002)

Ontologies l An ontology contains the topic map’s input l Examples of ontologies are thesauri, taxonomies, word-nets, etc l Ontologies are not necessarily structured hierarchically

Topic map technology l XTM – XML Topic Maps l HyTM – SGML based l Topic map engines using databases of various kinds l XTM + XSL

Example of XTM 1

Example of XTM 2

Example of XTM 3

Characteristics of topic maps 1. topics have names 2. topics are knit together using associations 3. a topic may be categorised by an unlimited number of topic types 4. topic types are topics on a higher level of abstraction 5. association types are association on a higher level of abstraction 6. occurrences may be external or internal to the topic map 7. topics can be disambiguated using subject indicators

Topic maps for knowledge organisation Two challenges: l Hierarchical versus associative structuring l Published Subject Indicators

Hierarchies and networks l Hierarchical in the thesaurus tradition with strict rules on what associative relationships should be allowed or l Open up for “unlimited” implementation of associative relationships

Published Subject Indicators l PSIs contain “definitions” of subjects l Who should provide such definitions? l Centralised control or principle of natural selection? l LIS traditionally aimed for control l WWW of anarchistic nature