Experiments on Element and Document Statistics for XML Retrieval based on tree matching

This paper presents an information retrieval model on XML documents based on tree matching. Queries and documents are represented by extended trees. An extended tree is built starting from the original tree, with additional weighted virtual links between each node and its indirect descendants allowing to directly reach each descendant. Therefore only one level separates between each node and its indirect descendants. This allows to compare the user query and the document with flexibility and with respect to the structural constraints of the query. The content of each node is very important to decide weither a document element is relevant or not, thus the content should be taken into account in the retrieval process. We separate between the structure-based and the contentbased retrieval processes. The content-based score of each node is commonly based on the well-known Tf × Idf criteria. In this paper, we compare between this criteria and another one we call Tf× Ief . The comparison is based on some experiments, this model is used for content only queries (CO) and content and structure ones (CAS). Some experiments have been undertaken into 2 datasets provided by INEX to show the effectiveness of our approach on one hand and those of both weighting functions on the other. Keywords—XML retrieval, INEX’04, INEX’05, Tf × Idf , Tf × Ief