Now showing items 1-11 of 11

    • Joint mixability of some integer matrices 

      Bellini, F.; Karaşan, O. E.; Pınar, M. Ç. (Elsevier B.V.Elsevier BV, 2016)
      We study the problem of permuting each column of a given matrix to achieve minimum maximal row sum or maximum minimal row sum, a problem of interest in probability theory and quantitative finance where quantiles of a random ...
    • The latest arrival hub location problem 

      Kara, B. Y.; Tansel, B. Ç. (Institute for Operations Research and the Management Sciences (INFORM), 2001)
      The traditionally studied hub location problems in the literature pay attention to flight times but not to transient times spent at hubs for unloading, loading, and sorting operations. The transient times may constitute a ...
    • Noise enhanced detection in the restricted Bayesian framework 

      Bayram, S.; Gezici, S.; Poor H.V. (2010)
      Effects of additive independent noise are investigated for sub-optimal detectors according to the restricted Bayes criterion. The statistics of optimal additive noise are characterized. Also, sufficient conditions for ...
    • Noise-enhanced M-ary hypothesis-testing in the minimax framework 

      Bayram, S.; Gezici, S. (2009)
      In this study, the effects of adding independent noise to observations of a suboptimal detector are studied for M-ary hypothesis-testing problems according to the minimax criterion. It is shown that the optimal additional ...
    • Optimal detector randomization for multiuser communications systems 

      Tutay, M. E.; Gezici, S.; Arikan, O. (IEEE, 2013)
      Optimal detector randomization is studied for the downlink of a multiuser communications system, in which users can perform time-sharing among multiple detectors. A formulation is provided to obtain optimal signal amplitudes, ...
    • Optimal randomization of signal constellations on downlink of a multiuser DS-CDMA system 

      Tutay, M. E.; Gezici, S.; Arikan, O. (IEEE, 2013-10)
      In this study, the jointly optimal power control with signal constellation randomization is proposed for the downlink of a multiuser communications system. Unlike a conventional system in which a fixed signal constellation ...
    • Robust estimation in flat fading channels under bounded channel uncertainties 

      Donmez, M. A.; Inan, H. A.; Kozat, S. S. (Elsevier, 2013-09)
      We investigate channel equalization problem for time-varying flat fading channels under bounded channel uncertainties. We analyze three robust methods to estimate an unknown signal transmitted through a time-varying flat ...
    • Robust least squares methods under bounded data uncertainties 

      Vanli, N. D.; Donmez, M. A.; Kozat, S. S. (Academic Press, 2015)
      We study the problem of estimating an unknown deterministic signal that is observed through an unknown deterministic data matrix under additive noise. In particular, we present a minimax optimization framework to the least ...
    • Signal and detector randomization for multiuser and multichannel communication systems 

      Tutay, Mehmet Emin (Bilkent University, 2013)
      Randomization can be considered as a possible approach to enhance error performance of communication systems subject to average power constraints. In the first part of this dissertation, we consider downlink of a multiuser ...
    • Stochastic signal design on the downlink of a multiuser communications system 

      Tutay, Mehmet Emin; Gezici, Sinan; Arıkan, Orhan (IEEE, 2012-06)
      Stochastic signal design is studied for the downlink of a multiuser communications system. First, a formulation is proposed for the joint design of optimal stochastic signals. Then, an approximate formulation, which can ...
    • Stochastic signaling in the presence of channel state information uncertainty 

      Goken, C.; Gezici, S.; Arikan, O. (Elsevier, 2013)
      In this paper, stochastic signaling is studied for power-constrained scalar valued binary communications systems in the presence of uncertainties in channel state information (CSI). First, stochastic signaling based on the ...