Now showing items 1-20 of 25

    • Adaptive and efficient nonlinear channel equalization for underwater acoustic communication 

      Kari, D.; Vanli, N. D.; Kozat, S. S. (Elsevier B.V., 2017)
      We investigate underwater acoustic (UWA) channel equalization and introduce hierarchical and adaptive nonlinear (piecewise linear) channel equalization algorithms that are highly efficient and provide significantly improved ...
    • Advanced partitioning and communication strategies for the efficient parallelization of the multilevel fast multipole algorithm 

      Ergül O.; Gürel, Levent (IEEE, 2010)
      Large-scale electromagnetics problems can be solved efficiently with the multilevel fast multipole algorithm (MLFMA) [1], which reduces the complexity of matrix-vector multiplications required by iterative solvers from O(N ...
    • Bağlam ağaçları ile ardışık doğrusal olmayan bağlanım 

      Vanlı, N. Denizcan; Kozat, Süleyman S. (IEEE, 2014-04)
      Bu bildiride, ardışık doğrusal olmayan bağlanım problemi incelenmiş ve bağlam ağaçları kullanarak etkili bir öğrenme algoritması sunulmuştur. Bu amaçla, bağlanım alanı parçalara ayrılmış ve oluşan bölgeler bağlam ağacı ile ...
    • Competitive and online piecewise linear classification 

      Özkan, Hüseyin; Donmez, M.A.; Pelvan O.S.; Akman, A.; Kozat, Süleyman S. (IEEE, 2013)
      In this paper, we study the binary classification problem in machine learning and introduce a novel classification algorithm based on the 'Context Tree Weighting Method'. The introduced algorithm incrementally learns a ...
    • Connectivity-guided adaptive lifting transform for image like compression of meshes 

      Köse, Kıvanç; Çetin, Ahmet Enis; Güdükbay, Uğur; Onural, Levent (IEEE, 2007-05)
      We propose a new connectivity-guided adaptive wavelet transform based mesh compression framework. The 3D mesh is first transformed to 2D images on a regular grid structure by performing orthogonal projections onto the image ...
    • Data imputation through the identification of local anomalies 

      Ozkan, H.; Pelvan, O. S.; Kozat, S. S. (Institute of Electrical and Electronics Engineers Inc., 2015)
      We introduce a comprehensive and statistical framework in a model free setting for a complete treatment of localized data corruptions due to severe noise sources, e.g., an occluder in the case of a visual recording. Within ...
    • A distributed and dynamic data gathering protocol for sensor networks 

      Tan, Hüseyin Özgür; Körpeoğlu, İbrahim; Stojmenović, I. (IEEE, 2007-05)
      In this paper we propose a distributed, self organizing, robust and energy efficient data gathering algorithm for sensor networks operating in environments where all the sensor nodes are not in direct communication range ...
    • Dynamic point-region quadtrees for particle simulations 

      Oğuz, O.; Durupınar, F.; Güdükbay U. (Elsevier Inc., 2013)
      We propose an algorithm for dynamically updating point-region (PR) quadtrees. Our algorithm is optimized for simultaneous update of data points comprising a quadtree. The intended application area focuses on simulating ...
    • An energy efficient scatternet formation algorithm for Bluetooth-based sensor networks 

      Saginbekov, Sain; Körpeoğlu, İbrahim (IEEE, 2005-02)
      In this paper, we propose an energy-efficient scatternet formation algorithm for Bluetooth based sensor networks. The algorithm is based on first computing a shortest path tree from the base station to all sensor nodes and ...
    • An image watermarking algorithm via Zero Assigned Filter Banks 

      Yücel, Zeyep; Özgüler, A. Bülent (IEEE, 2005-12)
      In this paper a new method for digital image watermarking based on Zero Assigned Filter Banks and Embedded Zero Tree Wavelet (EZW) algorithm is presented. An image is partitioned into 128 × 128 subblocks and each block is ...
    • Linear MMSE-optimal turbo equalization using context trees 

      Kim, K.; Kalantarova, N.; Kozat, S. S.; Singer, A. C. (IEEE, 2013)
      Formulations of the turbo equalization approach to iterative equalization and decoding vary greatly when channel knowledge is either partially or completely unknown. Maximum aposteriori probability (MAP) and minimum ...
    • Nonrectangular wavelets for multiresolution mesh analysis and compression 

      Köse, Kıvanç; Çetin, A. Enis; Güdükbay, Uğur; Onural, Levent (IEEE, 2006)
      We propose a new Set Partitioning In Hierarchical Trees (SPIHT) based mesh compression framework. The 3D mesh is first transformed to 2D images on a regular grid structure. Then, this image-like representation is wavelet ...
    • A novel broadband multilevel fast multipole algorithm with incomplete-leaf tree structures for multiscale electromagnetic problems 

      Takrimi, M.; Ergül, Ö.; Ertürk, V. B. (Institute of Electrical and Electronics Engineers Inc., 2016)
      An efficient and versatile broadband multilevel fast multipole algorithm (MLFMA), which is capable of handling large multiscale electromagnetic problems with a wide dynamic range of mesh sizes, is presented. By invoking a ...
    • Novelty detection using soft partitioning and hierarchical models 

      Ergen, Tolga; Gökçesu, Kaan; Şimşek, Mustafa; Kozat, Süleyman Serdar (IEEE, 2017)
      In this paper, we study novelty detection problem and introduce an online algorithm. The algorithm sequentially receives an observation, generates a decision and then updates its parameters. In the first step, to model the ...
    • Piecewise nonlinear regression via decision adaptive trees 

      Vanlı, N. Denizcan; Sayın, Muhammed O.; Ergüt, S.; Kozat, Süleyman S. (IEEE, 2014-09)
      We investigate the problem of adaptive nonlinear regression and introduce tree based piecewise linear regression algorithms that are highly efficient and provide significantly improved performance with guaranteed upper ...
    • The robust spanning tree problem with interval data 

      Yaman, H.; Karaşan, O. E.; Pınar, M. Ç. (Elsevier, 2001)
      Motivated by telecommunications applications we investigate the minimum spanning tree problem where edge costs are interval numbers. Since minimum spanning trees depend on the realization of the edge costs, we de5ne the ...
    • Searching for repeated video sequences 

      Can, Tolga; Duygulu, Pınar (ACM, 2007-09)
      In this paper, we propose a new method to search different instances of a video sequence inside a long video and/or video collection. The proposed method is robust to view point and illumination changes which may occur ...
    • Sequential Decoding of Low-Density Parity-Check Codes by Adaptive Reordering of Parity Checks 

      Radosavljevic, B.; Arikan, E.; Hajek, B. (1992)
      Decoding algorithms are investigated in which unpruned codeword trees are generated from an ordered list of parity checks. The order is computed from the received message, and low-density parity-check codes are used to ...
    • Shortest unique substring query revisited 

      Ileri, Atalay Mert; Külekci, M.O.; Xu, B. (Springer, Cham, 2014)
      We revisit the problem of finding shortest unique substring (SUS) proposed recently by Pei et al. (ICDE'13). We propose an optimal O(n) time and space algorithm that can find an SUS for every location of a string of size ...
    • Stereoscopic view-dependent visualization of terrain height fields 

      Güdükbay U.; Yilmaz, T. (IEEE, 2002)
      Visualization of large geometric environments has always been an important problem of computer graphics. In this paper, we present a framework for the stereoscopic view-dependent visualization of large scale terrain models. ...