A Unified Framework for Wrapping, Mediating and Restructuring Information from the Web

The goal of information extraction from the Web is to provide an integrated view on heterogeneous information sources via a common data model and query language. A main problem with current approaches is that they rely on very different formalisms sind tools for wrappers and mediators, thus leading to an "impedance mismatch" between the wrapper and mediator level. In contrast, our approach integrates wrapping and mediation in a unified framework based on an object-oriented data model which represents both the Web structure and the data of the application domain. Wrappers and mediators are written in a rule-based object-oriented language which is augmented with features for Web access and structured document analysis, i.e., pattern matching by regular expressions and SGML parsing. In this paper, we develop generic, reusable rule patterns for typical extraction, integration, and restructuring tasks using this framework. We show the practicability of our approach by using the FLORID system [10].