document: Data extraction from the Web based on pre-defined schema With the development of the Internet , the World Wide Web has become an invaluable information source for most organizations . However , most documents available from the Web are in HTML form which is originally designed for document formatting with little consideration of its contents . Effectively extracting data from such documents remains a nontrivial task . In this paper , we present a schema-guided approach to extracting data from HTML pages . Under the approach , the user defines a schema specifying what to be extracted and provides sample mappings between the schema and the HTML page . The system will induce the mapping rules and generate a wrapper that takes the HTML page as input and produces the required data in the form of XML conforming to the user-defined schema . A prototype system implementing the approach has been developed . The preliminary experiments indicate that the proposed semi-automatic approach is not only easy to use but also able to produce a wrapper that extracts required data from inputted pages with high accuracy
doc_bio_tags: B I O O O O O O B O O O O O B O O O O O O O O O B I O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
extractive_keyphrases: data extraction internet information source schema html
abstractive_keyphrases: wrapper generation data integration distributed database queries