Here from the CrissCross site is a brief description:
In CrissCross the subject headings of the German subject headings authority file (SWD) are mapped to notations of the Dewey Decimal Classification (DDC). The method chosen for the mapping procedure is a directional one: the German subject headings function as initial vocabulary, the DDC as target classification. Appropriate DDC numbers are added directly to the particular SWD data record. The SWD Subject Groups serve as a starting point for the creation of work packages.
The mapping is carried out as specific as possible (Deep level mapping); if necessary, institutional notations are built according to the DDC number building instructions. Due to the referential polysemy of many subject headings, one subject heading can be assigned to several DDC classes (One-to-many mapping). The strength of correspondence of SWD terms and DDC classes is expressed by a code, the so-called "Degree of Determinacy" (abbreviated: Det). In future retrieval systems the Degrees of Determinacy shall be used for ranking as well as for regulation of recall and precision of search results.
The CrissCross web site has more information and many links to publications, presentations, and related projects.
If you can be in the home of CrissCross in July, you are invited to a conference.
Concepts in Context – Cologne Conference on Interoperability and Semantics in Knowledge Organization
Cologne University of Applied Sciences, Cologne, Germany
Date: July 19th and 20th, 2010
Short conference description:
In cooperation with the German National Library (DNB), the Institute of Information Management (IIM) at the Cologne University of Applied Sciences would like to invite you to attend the Cologne Conference on Interoperability and Semantics in Knowledge Organization Concepts in Context on July 19th and 20th at the Cologne University of Applied Sciences in Cologne, Germany. The first day gives a review of the CrissCross project. The attendance of the event is free of charge. You will find the programme as well as further information and a registration form on the conference website: http://linux2.fbi.fh-koeln.de/cisko2010/index_en.html.