Logic-based web information extraction

The Web wrapping proble, i.e., the problem of extracting structured information from HTML documents, is one of great practical importance. The often observed information overload that users of the Web experience witnesses the lack of intelligent and encompassing Web services that provide high-quality collected and value-added inforamtion. The Web wrapping problem has been addressed by a significant amount of research work. Previous work can be classified into two categories, depending on whether the HTML input is regarded as a sequential character string (e.g., [34, 27, 24, 30, 23]) or a pre-parsed document tree (for instance, [35, 25, 22, 29, 3, 2, 26]). The latter category of work thus assumes that systems may make use of an existing HTML parser as a front and.

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