Now showing items 1-18 of 18

    • Algorithms for within-cluster searches using inverted files 

      Altıngövde, İsmail Şengör; Can, Fazlı; Ulusoy, Özgür (Springer, 2006-11)
      Information retrieval over clustered document collections has two successive stages: first identifying the best-clusters and then the best-documents in these clusters that are most similar to the user query. In this paper, ...
    • An automatic approach to construct domain-specific web portals 

      Altıngövde, İsmail Şengör; Özcan, Rıfat; Çetintaş, Süleyman; Yılmaz, Hakan; Ulusoy, Özgür (ACM, 2007-11)
      We describe the architecture of an automatic domain-specific Web portal construction system. The system has three major components: i) a focused crawler that collects the domain-specific pages on the Web, ii) an information ...
    • Efficient processing of category-restricted queries for web directories 

      Altıngövde, İsmail Şengör; Can, Fazlı; Ulusoy, Özgür (Springer, 2008-03-04)
      We show that a cluster-skipping inverted index (CS-IIS) is a practical and efficient file structure to support category-restricted queries for searching Web directories. The query processing strategy with CS-IIS improves ...
    • Evolution of web search results within years 

      Altıngövde, İsmail Şengör; Özcan, Rıfat; Ulusoy, Özgür (ACM, 2011-07)
      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.
    • Exploiting index pruning methods for clustering XML collections 

      Altıngövde, İsmail Şengör; Atılgan, Duygu; Ulusoy, Özgür (Springer, Berlin, Heidelberg, 2010)
      In this paper, we first employ the well known Cover-Coefficient Based Clustering Methodology (C3M) for clustering XML documents. Next, we apply index pruning techniques from the literature to reduce the size of the document ...
    • Exploiting query views for static index pruning in web search engines 

      Altıngövde, İsmail Şengör; Özcan, Rıfat; Ulusoy, Özgür (ACM, 2009-11)
      We propose incorporating query views in a number of static pruning strategies, namely term-centric, document-centric and access-based approaches. These query-view based strategies considerably outperform their counterparts ...
    • How k-12 students search for learning?: analysis of an educational search engine log 

      Usta, Arif; Altıngövde, İsmail Şengör; Vidinli, İ. B.; Özcan, R.; Ulusoy, Özgür (ACM, 2014-07)
      In this study, we analyze an educational search engine log for shedding light on K-12 students' search behavior in a learning environment. We specially focus on query, session, user and click characteristics and compare ...
    • Large-scale cluster-based retrieval experiments on Turkish texts 

      Altıngövde, İsmail Şengör; Özcan, Rıfat; Öcalan Hüseyin C.; Can, Fazlı; Ulusoy, Özgür (ACM, 2007)
      We present cluster-based retrieval (CBR) experiments on the largest available Turkish document collection. Our experiments evaluate retrieval effectiveness and efficiency on both an automatically generated clustering ...
    • Osmanlı arşivleri içerik-bazlı sorgulama (İBS) sistemi 

      Altıngövde, İsmail Şengör; Şaykol, Ediz; Ulusoy, Özgür; Güdükbay, Uğur; Çetin, A. Enis; Göçmen, M. (2006-04)
      We propose a content-based retrieval (CBR) system for digital Ottoman archive documents. In this system, the symbols extracted from the documents are matched with the most similar one in the symbol library, which is created ...
    • A practitioner's guide for static index pruning 

      Altıngövde, İsmail Şengör; Özcan, Rıfat; Ulusoy, Özgür (Springer, 2009-04)
      We compare the term- and document-centric static index pruning approaches as described in the literature and investigate their sensitivity to the scoring functions employed during the pruning and actual retrieval stages. ...
    • Space efficient caching of query results in search engines 

      Özcan, Rıfat; Altıngövde, İsmail Şengör; Ulusoy Özgür (IEEE, 2008-10)
      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 ...
    • Static query result caching revisited 

      Özcan, Rıfat; Altıngövde, İsmail Şengör; Ulusoy, Özgür (ACM, 2008-04)
      Query result caching is an important mechanism for search engine efficiency. In this study, we first review several query features that are used to determine the contents of a static result cache. Next, we introduce a new ...
    • Strategies for setting time-to-live values in result caches 

      Sazoğlu, Fethi Burak; Cambazoğlu, B. B.; Özcan, R.; Altıngövde, İsmail Şengör; Ulusoy, Özgür (ACM, 2013-10-11)
      In web query result caching, staleness of queries are often bounded via a time-to-live (TTL) mechanism, which expires the validity of cached query results at some point in time. In this work, we evaluate the performance ...
    • Timestamp-based cache invalidation for search engines 

      Alıcı, Sadiye; Altıngövde, İsmail Şengör; Özcan, Rıfat; Cambazoglu, B.B.; Ulusoy, Özgür (ACM, 2011)
      We propose a new mechanism to predict stale queries in the result cache of a search engine. The novelty of our approach is in the use of timestamps in staleness predictions. We show that our approach incurs very little ...
    • Topic-Centric Querying of Web Information Resourcest 

      Altıngövde, İsmail Şengör; Özel, Selma A.; Ulusoy, Özgür; Özsoyoğlu G.; Özsoyoğlu, Z.M. (Springer, Berlin, Heidelberg, 2001)
      This paper deals with the problem of modeling web information resources using expert knowledge and personalized user information, and querying them in terms of topics and topic relationships. We propose a model for web ...
    • Towards detecting media bias by utilizing user comments 

      Yigit-Sert, S.; Altıngövde, İsmail Şengör; Ulusoy, Özgür (ACM, 2016-05)
      Automatic detection of media bias is an important and challenging problem. We propose to leverage user comments along with the content of the online news articles to automatically identify the latent aspects of a given ...
    • Utilization of navigational queries for result presentation and caching in search engines 

      Özcan, Rıfat; Altıngövde, İsmail Şengör; Ulusoy, Özgür (ACM, 2008-10)
      We propose result page models with varying granularities for navigational queries and show that this approach provides a better utilization of cache space and reduces bandwidth requirements.
    • XML retrieval using pruned element-index files 

      Altıngövde, İsmail Şengör; Atılgan, Duygu; Ulusoy, Özgür (Springer, Berlin, Heidelberg, 2010)
      An element-index is a crucial mechanism for supporting content-only (CO) queries over XML collections. A full element-index that indexes each element along with the content of its descendants involves a high redundancy and ...