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3.3.2: Classifications

Used to organize the objects of a domain into disjoint sets of related or similar objects.

Especially useful for physical objects:

ZUGANG3.3.2.1: Classification

Hierarchical classification systems yield tree structures with varying levels of generalization

Besides strongly hierarchical classification system there are systems with weaker hierarchies, allowing an object to be in several classes or to have several generalizations.

Example: The seat of a car may be seen as a sitting device or as part of a car.

ZUGANG3.3.2.2: Dewey Decimal Classification (DDC)

Hierarchical classifications are build before objects (instances) are classified (they are pre-coordinated) This means that they offer little flexibility for new developments, little expressive power. Means to add more expressiveness: Add information that is not specific to a class using suffixes to the code of a class: 860=20: "Spanish and Portuguese literatures in English language" (860: Spanish and Portuguese literatures) 622.33(493): coal mining in Belgium (622.33: coal mining)

(Examples adapted from Manecke, 1997 [->])

This allows to construct a suitable classification code when a object is classified ( post-coordination).


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