dublin core -> mods

There are two types of keywords used as metadata: controlled terms and free terms. Free terms have the advantage that metadata creators can freely select keywords, but there also exists a disadvantage that the information retrieval recall ratio might be reduced. The recall ratio can be improved by using controlled terms. But creating and maintaining controlled vocabularies has an enormous cost. In addition, many existing controlled vocabularies are published in formats less suitable for programming. We introduce a JavaScript library called “covo.js” that enables us to make use of controlled vocabularies as metadata for the organization of web pages.

blogs.loc.gov