Now showing items 1-20 of 123

    • Adaptive schemes for location update generation in execution location-dependent continuous queries 

      Lam, Kam-Yiu; Ulusoy, Özgür (Elsevier Inc., 2006-04)
      An important feature that is expected to be owned by today's mobile computing systems is the ability of processing location-dependent continuous queries on moving objects. The result of a location-dependent query depends ...
    • Adaptive time-to-live strategies for query result caching in web search engines 

      Alıcı, Sadiye; Altıngövde, I. Ş.; Rıfat, Özcan; Cambazoğlu, B. Barla; Ulusoy, Özgür (2012)
      An important research problem that has recently started to receive attention is the freshness issue in search engine result caches. In the current techniques in literature, the cached search result pages are associated ...
    • 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, ...
    • Analysis of concurrency control protocols for real-time database systems 

      Ulusoy, Özgür (Elsevier, 1998)
      This paper provides an approximate analytic solution method for evaluating the performance of concurrency control protocols developed for real-time database systems (RTDBSs). Transactions processed in a RTDBS are associated ...
    • An analysis of social networks based on tera-scale telecommunication datasets 

      Aksu, Hidayet; Körpeoğlu, İbrahim; Ulusoy, Özgür (IEEE Computer Society, 2019)
      With the popularization of mobile phone usage, telecommunication networks have turned into a socially binding medium. Considering the traces of human communication held inside these networks, telecommunication networks are ...
    • An approximate analysis of a real-time database concurrency control protocol via Markov modeling 

      Ulusoy, Özgür (Association for Computing Machinery (ACM), 1993-03)
    • Association rules for supporting hoarding in mobile computing environments 

      Saygın, Yücel; Ulusoy, Özgür; Elmagarmid, A. K. (IEEE, 2000)
      One of the features that a mobile computer should provide is disconnected operation which is performed by hoarding. The process of hoarding can be described as loading the data items needed in the future to the client cache ...
    • Automated construction of fuzzy event sets and its application to active databases 

      Saygin, Y.; Ulusoy, Özgür (IEEE, 2001)
      Fuzzy sets and fuzzy logic research aims to bridge the gap between the crisp world of math and the real world. Fuzzy set theory was applied to many different areas, from control to databases. Sometimes the number of events ...
    • 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 ...
    • Automatic detection of salient objects and spatial relations in videos for a video database system 

      Sevilmiş, T.; Baştan M.; Güdükbay, Uğur; Ulusoy, Özgür (Elsevier BV, 2008-10)
      Multimedia databases have gained popularity due to rapidly growing quantities of multimedia data and the need to perform efficient indexing, retrieval and analysis of this data. One downside of multimedia databases is the ...
    • Bilkent University Multimedia Database Group at TRECVID 2008 

      Küçüktunç, Onur; Baştan, Muhammet; Güdükkbay, Uğur; Ulusoy, Özgür (National Institute of Standards and Technology, 2008-11)
      Bilkent University Multimedia Database Group (BILMDG) participated in two tasks at TRECVID 2008: content-based copy detection (CBCD) and high-level feature extraction (FE). Mostly MPEG-7 [1] visual features, which are also ...
    • Bilvideo-7: an MPEG-7-compatible video indexing and retrieval system 

      Baştan M.; Çam, H.; Güdükbay, Uğur; Ulusoy, Özgür (Institute of Electrical and Electronics Engineers, 2010-07)
      BilVideo-7 is an MPEG-7-compatible, distributed, video indexing and retrieval system that supports complex multimodal queries in a unified framework.
    • BilVideo: a video database management system 

      Dönderler, M. E.; Şaykol, E.; Ulusoy, Özgür; Güdükbay, Uğur (IEEE, 2003)
      The BilVideo video database management system provides integrated support for spatiotemporal and semantic queries for video. BilVideo can support any application with video data searching needs. It's query language provides ...
    • BilVideo: Design and implementation of a video database management system 

      Dönderler, M. E.; Şaykol, E.; Arslan, U.; Ulusoy, Özgür; Güdükbay, Uğur (Springer, 2005)
      With the advances in information technology, the amount of multimedia data captured, produced, and stored is increasing rapidly. As a consequence, multimedia content is widely used for many applications in today's world, ...
    • Cache-based query processing for search engines 

      Cambazoglu, B. B.; Altıngovde, I. S.; Ozcan, R.; Ulusoy, Özgür (Association for Computing Machinery, 2012-11-01)
      In practice, a search engine may fail to serve a query due to various reasons such as hardware/network failures, excessive query load, lack of matching documents, or service contract limitations (e.g., the query rate limits ...
    • Characterizing Gnutella network properties for peer-to-peer network simulation 

      Çıracı, Selim; Körpeoğlu, İbrahim; Ulusoy, Özgür (Springer, Berlin, Heidelberg, 2005)
      A P2P network that is overlayed over Internet can consist of thousands, or even millions of nodes. To analyze the performance of a P2P network, or an algorithm or protocol designed for a P2P network, simulation studies ...
    • Characterizing web search queries that match very few or no results 

      Altıngövde, İ. Ş.; Blanco, R.; Cambazoğlu, B. B.; Özcan, Rıfat; Sarıgil, Erdem; Ulusoy, Özgür (ACM, 2012-11)
      Despite the continuous efforts to improve the web search quality, a non-negligible fraction of user queries end up with very few or even no matching results in leading web search engines. In this work, we provide a detailed ...
    • Characterizing, predicting, and handling web search queries that match very few or no results 

      Sarıgil, Erdem; Altıngövde, I. S.; Blanco, R.; Cambazoğlu, B. B.; Özcan, R.; Ulusoy, Özgür (John Wiley & Sons, 2018)
      A non‐negligible fraction of user queries end up with very few or even no matching results in leading commercial web search engines. In this work, we provide a detailed characterization of such queries and show that search ...
    • Cluster searching strategies for collaborative recommendation systems 

      Altingovde, I. S.; Subakan, Ö. N.; Ulusoy, Özgür (2013)
      In-memory nearest neighbor computation is a typical collaborative filtering approach for high recommendation accuracy. However, this approach is not scalable given the huge number of customers and items in typical commercial ...
    • Clustering mobile trajectories for resource allocation in mobile environments 

      Katsaros, D.; Nanopoulos, A.; Karakaya, M.; Yavas, G.; Ulusoy, Özgür; Manolopoulos, Y. (Springer, 2003)
      The recent developments in computer and communication technologies gave rise to Personal Communication Systems. Due to the nature of the PCS, the bandwidth allocation problem arises, which is based on the notion of ...