Hierarchical document signature: A specialized application of fuzzy signature for document computing

We develop document computing procedures for the analysis of discourse structures within a document, represented by hierarchical document signatures. A signature is a string of data characterizing a certain case (e.g. characteristics of a sentence in case of a document). The place of the individual data is fixed within the string, it holds a local value semantics. Fuzzy granulation is a semantic background technique for all kinds of information which originates from human estimation or recorded by human valuation of numerical data. For analysis of such data the development of special procedures is suggested, different from the usual statistical methods. We used a form of fuzzy signature, called hierarchical document signature to modularize an unstructured document in a hierarchical manner, from Document level to sentence level, sentence level to attribute level and then to word level. We used occurrence of words as the information of the lowest module to find the similarity among the next higher module by aggregating the signature values giving sentence pair coherence.