Now showing items 1-20 of 24

    • Algebraic error analysis of collinear feature points for camera parameter estimation 

      Urfalioglu, O.; Thormählen, T.; Broszio, H.; Mikulastik, P.; Cetin, A. E. (Elsevier, 2011-01-04)
      In general, feature points and camera parameters can only be estimated with limited accuracy due to noisy images. In case of collinear feature points, it is possible to benefit from this geometrical regularity by correcting ...
    • Constrained nonlinear programming for volatility estimation with GARCH models 

      Altay-Salih, A.; Pınar, M. Ç.; Leyffer, S. (2003)
      This paper proposes a constrained nonlinear programming view of generalized autoregressive conditional heteroskedasticity (GARCH) volatility estimation models in financial econometrics. These models are usually presented ...
    • A distributed positioning algorithm for cooperative active and passive sensors 

      Gholami, M.R.; Gezici, S.; Rydström, M.; Ström, E.G. (2010)
      The problem of positioning a target node is studied for wireless sensor networks with cooperative active and passive sensors. Two-way time-of-arrival and time-difference-of-arrival measurements made by both active and ...
    • Enhanced position estimation via node cooperation 

      Sahinoglu, Z.; Gezici, S. (2010)
      Two-way time-of-arrival (TW-ToA) is a widely used ranging protocol that can provide the distance between two devices without time synchronization. One drawback of the TW-ToA is poor positioning accuracy in the absence of ...
    • Hybrid TW-TOA/TDOA positioning algorithms for cooperative wireless networks 

      Gholami, M.R.; Gezici, S.; Ström, E.G.; Rydström, M. (2011)
      The problem of positioning an unknown target is studied for a cooperative wireless sensor network using hybrid two-way time-of-arrival and time-difference-of-arrival measurements. A maximum likelihood estimator (MLE) can ...
    • Improved position estimation using hybrid TW-TOA and TDOA in cooperative networks 

      Gholami, M. R.; Gezici, S.; Ström, E. G. (Institute of Electrical and Electronics Engineers, 2012-04-13)
      This paper addresses the problem of positioning multiple target nodes in a cooperative wireless sensor network in the presence of unknown turn-around times. In this type of cooperative networks, two different reference ...
    • Inflation and inflation uncertainty in the G-7 countries 

      Berument, H.; Dincer, N. N. (Elsevier BV, 2005)
      This study examines the relationship between inflation and inflation uncertainty in the G-7 countries for the period from 1957 to 2001. The causality between the inflation and inflation uncertainty is tested by using the ...
    • Interactive training of advanced classifiers for mining remote sensing image archives 

      Aksoy, S.; Koperski, K.; Tusk, C.; Marchisio G. (2004)
      Advances in satellite technology and availability of down-loaded images constantly increase the sizes of remote sensing image archives. Automatic content extraction, classification and content-based retrieval have become ...
    • A locally optimal seasonal unit-root test 

      Caner, M. (Taylor & Francis Inc., 1998)
      This article proposes a locally best invariant test of the null hypothesis of seasonal stationarity against the alternative of seasonal unit roots at all or individual seasonal frequencies. An asymptotic distribution theory ...
    • Location and curvature estimation of spherical targets using multiple sonar time-of-flight measurements 

      Barshan, B. (Institute of Electrical and Electronics Engineers, 1999-12)
      A novel, flexible, three-dimensional multisensor sonar system is described to localize the center of a generalized spherical target and estimate its radius of curvature. Point, line, and planar targets are included as ...
    • Maximum likelihood estimation of Gaussian mixture models using particle swarm optimization 

      Arı, Ç.; Aksoy, S. (IEEE, 2010)
      We present solutions to two problems that prevent the effective use of population-based algorithms in clustering problems. The first solution presents a new representation for arbitrary covariance matrices that allows ...
    • Maximum likelihood estimation of Gaussian mixture models using stochastic search 

      Ar, C.; Aksoy, S.; Arıkan, O. (Elsevier BV, 2012)
      Gaussian mixture models (GMM), commonly used in pattern recognition and machine learning, provide a flexible probabilistic model for the data. The conventional expectationmaximization (EM) algorithm for the maximum likelihood ...
    • On the reliability exponent of the exponential timing channel 

      Arikan, E. (IEEE, 2002)
      We determine the reliability exponent E(R) of the Anantharam-Verdú exponential server timing channel with service rate μ for all rates R between a critical rate R c = (μ/4) log 2 and the channel capacity C = e -1μ. For ...
    • Positioning algorithms for cooperative networks in the presence of an unknown turn-around time 

      Gholami, M.R.; Gezici, S.; Ström, E.G.; Rydström, M. (2011)
      This paper addresses the problem of single node positioning in cooperative network using hybrid two-way time-of-arrival and time-difference-of-arrival where, the turn-around time at the target node is unknown. Considering ...
    • Robust direction-of-arrival estimation in non-Gaussian noise 

      Yardımcı, Y.; Çetin, A. E.; Cadzow, J. A. (Institute of Electrical and Electronics Engineers, 1998-05)
      In this correspondence, a nonlinearly weighted least-squares method is developed for robust modeling of sensor array data. Weighting functions for various observation noise scenarios are determined using maximum likelihood ...
    • Signal denoising by piecewise continuous polynomial fitting 

      Yildiz, A.; Arikan, O. (2010)
      Piecewise smooth signal denoising is cast as a non-linear optimization problem in terms of transition boundaries and a parametric smooth signal family. Optimal transition boundaries for a given number of transitions are ...
    • Successive cancelation approach for doppler frequency estimation in pulse doppler radar systems 

      Soǧanci H.; Gezici, S. (2010)
      In this paper, a successive cancelation approach is proposed to estimate Doppler frequencies of targets in pulse Doppler radar systems. This technique utilizes the Doppler domain waveform structure of the received signal ...
    • A survey on wireless position estimation 

      Gezici, S. (Springer New York LLC, 2008)
      In this paper, an overview of various algorithms for wireless position estimation is presented. Although the position of a node in a wireless network can be estimated directly from the signals traveling between that node ...
    • Time delay estimation in cognitive radio systems 

      Kocak F.; Celebi H.; Gezici, S.; Qaraqe, K.A.; Arslan H.; Poor H.V. (2009)
      In cognitive radio systems, secondary users can utilize multiple dispersed bands that are not used by primary users. In this paper, time delay estimation of signals that occupy multiple dispersed bands is studied. First, ...
    • Time-delay estimation in dispersed spectrum cognitive radio systems 

      Kocak, F.; Celebi, H.; Gezici, S.; Qaraqe, K. A.; Arslan, H.; Poor, H. V. (SpringerOpen, 2010)
      Time-delay estimation is studied for cognitive radio systems, which facilitate opportunistic use of spectral resources. A two-step approach is proposed to obtain accurate time-delay estimates of signals that occupy multiple ...