Schema extraction for multimedia XML document retrieval

Multimedia XML data is a collection of multiple types of data sets tagged by XML elements. Such XML data can be retrieved not only by a Boolean connection with keywords but also by tag element-based query languages. In many cases, however, keyword-based queries result in either too many hits or too few results. It is not clear either what query to formulate in order to obtain a "good" size of query results. This paper proposes a method of schema extraction for multimedia XML data. Schemas are then leveled with respect to the frequency of topological document structures in a database. The topological structural information of these schemas is used to formulate queries and to rewrite queries for relaxation and restriction.