Content-based Navigation in a Mini-World Web

Abstract

Several database query languages have recently been developed to locate and retrieve documents in the vast network of World-Wide Web pages. These languages combine path expressions, which specify the structure of a path through the network to the desired information, with content predicates, which force the path to pass through pages with particular content. The straightforward implementation of these languages is based on breadth-first search of the network, with heavy reliance placed on the user's understanding of network topology to both direct and constrain the search via the appropriate use of the path expressions. In this paper we describe a system that removes the reliance on path expressions to safeguard the search during a query and enables the user to navigate by refining content rather than by specifying structure. Our system uses a cost-constrained model for query evaluation. Links between pages are assigned costs. The user controls how far a query can navigate by specify..