دانلود کتاب Classifying and Searching Hidden-Web Text Databases

The World-Wide Web continues to grow rapidly, which makes exploiting all available information a challenge. Search engines such as Google index an unprecedented amount of information, but still do not provide access to valuable content in text databases "hidden" behind search interfaces. For example, current search engines largely ignore the contents of the Library of Congress, the US Patent and Trademark database, newspaper archives, and many other valuable sources of information because their contents are not "crawlable." However, users should be able to find the information that they need with as little effort as possible, regardless of whether this information is crawlable or not. As a significant step towards this goal, we have designed algorithms that support browsing and searching-the two dominant ways of finding information on the web-over "hidden-web" text databases.