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Abstract

Web archives include both archives of contents originally published on the Web (e.g., the Internet Archive) but also archives of contents published long ago that are now accessible on the Web (e.g., the archive of The Times). Thanks to the increased awareness that web-born contents are worth preserving and to improved digitization techniques, web archives have grown in number and size. To unfold their full potential, search techniques are needed that consider their inherent special characteristics. This work addresses three important problems toward this objective and makes the following contributions: * We present the Time-Travel Inverted indeX (TTIX) as an efficient solution to time-travel text search in web archives, allowing users to search only the parts of the web archive that existed at a user's time of interest. * To counter negative effects that terminology evolution has on the quality of search results in web archives, we propose a novel query-reformulation technique, so that old but highly relevant documents are retrieved in response to today's queries. * For temporal information needs, for which the user is best satisfied by documents that refer to particular times, we describe a retrieval model that integrates temporal expressions (e.g., ``in the 1990s'') seamlessly into a language modeling approach. Experiments for each of the proposed methods show their efficiency and effectiveness, respectively, and demonstrate the viability of our approach to search in web archives.