What is Qualified Dublin Core?
“Qualified Dublin Core” is a term applied to Dublin Core metadata that employs additional information to increase the specificity of the metadata by refining the meaning , by specifying encoding schemes or controlled vocabularies, or to indicate a metadata value is a compound, or structured value. For example, a date may be further identified as a particular variety of date (date last modified, date published, etc.) and might be encoded according to a particular scheme that assures that it can be interpreted unambiguously. A subject term that is the value of the Subject element might be specified as having been selected from a particular controlled vocabulary such as the Dewey Decimal Classification. Qualifiers allow applications to increase the specificity or precision of the metadata, but also introduces complexity that can impair interoperability. Thus, designers of metadata systems are well advised to be conservative about deploying qualifiers in cases where interoperability is one
