1. A method for determining document structure similarity, comprising: segmenting, by a computing device, path sequences of Document Object Model (DOM) trees from a number of web pages into B components; determining path signals corresponding to the path sequences based on a count of the occurrences of particular paths in the B th component, wherein determining path signals comprises weighting the path signals based on path sequence characteristics of a DOM tree; transforming unique path signals into discrete wavelet signals; analyzing the discrete wavelet signals at multiple DOM tree resolution level, wherein analyzing the discrete wavelet signals comprises: computing a distance value for every common signal path of two DOM trees; and summing the distance values as a final tree distance for each of the two DOM trees; and outputting a document structure similarity decision based on the analyses of the discrete wavelet signals.