The Accessibility Dimension for Structured Document Retrieval

Structured document retrieval aims at retrieving the document components that best satisfy a query, instead of merely retrieving pre-de ned document units. This paper reports on an investigation of a tf -idf -acc approach, where tf and idf are the classical term frequency and inverse document frequency, and acc, a new parameter called accessibility, that captures the structure of documents. The tf -idf -acc approach is de ned using a probabilistic relational algebra. To investigate the retrieval quality and estimate the acc values, we developed a method that automatically constructs diverse test collections of structured documents from a standard test collection, with which experiments were carried out. The analysis of the experiments provides estimates of the acc values.