Efficient Wrapper Reinduction from Dynamic Web Sources

This paper investigates wrapper induction from web sites whose layout may change over time. We formulate the reinduction as an incremental learning problem and identify that wrapper induction from an incomplete label is a key problem to be solved. We propose a novel algorithm for incrementally inducing LR wrappers and show that this algorithm asymptotically identifies the correct wrapper as the number of tuples is increased. This property is used to propose a LR wrapper reinduction algorithm. This algorithm requires examples to be provided exactly once and there-after the algorithm can detect the layout changes and reinduce wrappers automatically. In experimental studies, we observe that the reinduction algorithm is able to achieve near perfect performance.