Browsing by Subject "Web searches"

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    Diversity and novelty in web search, recommender systems and data streams
    (Association for Computing Machinery, 2014-02) Santos, R. L. T.; Castells, P.; Altingovde, I. S.; Can, Fazlı
    This tutorial aims to provide a unifying account of current research on diversity and novelty in the domains of web search, recommender systems, and data stream processing.
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    Evolution of web search results within years
    (ACM, 2011-07) Altıngövde, İsmail Şengör; Özcan, Rıfat; Ulusoy, Özgür
    We provide a first large-scale analysis of the evolution of query results obtained from a real search engine at two distant points in time, namely, in 2007 and 2010, for a set of 630,000 real queries.
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    Space efficient caching of query results in search engines
    (IEEE, 2008-10) Özcan, Rıfat; Altıngövde, İsmail Şengör; Ulusoy Özgür
    Web search engines serve millions of query requests per day. Caching query results is one of the most crucial mechanisms to cope with such a demanding load. In this paper, we propose an efficient storage model to cache document identifiers of query results. Essentially, we first cluster queries that have common result documents. Next, for each cluster, we attempt to store those common document identifiers in a more compact manner. Experimental results reveal that the proposed storage model achieves space reduction of up to 4%. The proposed model is envisioned to improve the cache hit rate and system throughput as it allows storing more query results within a particular cache space, in return to a negligible increase in the cost of preparing the final query result page. © 2008 IEEE.
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    Timestamp-based result cache invalidation for web search engines
    (ACM, 2011) Alıcı, Sadiye; Altingovde I.S.; Özcan, Rıfat; Cambazoglu, B.B.; Ulusoy, Özgür
    The result cache is a vital component for efficiency of large-scale web search engines, and maintaining the freshness of cached query results is the current research challenge. As a remedy to this problem, our work proposes a new mechanism to identify queries whose cached results are stale. The basic idea behind our mechanism is to maintain and compare generation time of query results with update times of posting lists and documents to decide on staleness of query results. The proposed technique is evaluated using a Wikipedia document collection with real update information and a real-life query log. We show that our technique has good prediction accuracy, relative to a baseline based on the time-to-live mechanism. Moreover, it is easy to implement and incurs less processing overhead on the system relative to a recently proposed, more sophisticated invalidation mechanism.