Automatically Extracting Web Data Using Tree Structure

Extracting data from Web pages using wrappers is a fundamental problem arising in a large variety of applications of vast practical interests Proposed in this paper is a novel approach to the problem of automatically extracting data from Web pages It is based on the proposed page model that the data values are located in the semantic blocks, and semantic blocks are the main differences among HTML pages The approach automatically extracts data in four steps, discovering semantic blocks, differentiating roles on data items, inducing schema and computing extraction rule The intensive experiments on real Web sites show that the proposed approach can effectively extract desired data with high accuracies and with linear complexity