Now showing items 1-20 of 29

    • Calculation of the scalar diffraction field from curved surfaces by decomposing the three-dimensional field into a sum of Gaussian beams 

      Şahin, E.; Onural, L. (Optical Society of America, 2013)
      We present a local Gaussian beam decomposition method for calculating the scalar diffraction field due to a twodimensional field specified on a curved surface. We write the three-dimensional field as a sum of Gaussian beams ...
    • Capacity bounds for an ultra-wideband channel model 

      Ankan, E. (2004)
      There is an ongoing effort by the IEEE 802.15.3a subcommittee to reach a UWB personal area network standard. We estimate the achievable rates for such networks using a channel model specified by the same group. The analysis ...
    • Compressive sampling and adaptive multipath estimation 

      Pilanci, M.; Arikan, O. (2010)
      In many signal processing problems such as channel estimation and equalization, the problem reduces to a linear system of equations. In this proceeding we formulate and investigate linear equations systems with sparse ...
    • Computing moments of first passage times to a subset of states in Markov chains 

      Dayar T.; Akar, N. (SIAM, 2005)
      This paper presents a relatively efficient and accurate method to compute the moments of first passage times to a subset of states in finite ergodic Markov chains. With the proposed method, the moment computation problem ...
    • Continuous and discrete fractional fourier domain decomposition 

      Kutay, M. A.; Özaktaş, H. M.; Yetik, İ. Ş.; Özaktaş, H. (IEEE (Institute of Electrical and Electronics Engineers), 2000)
      We introduce the fractional Fourier domain decomposition for continuous and discrete signals and systems. A procedure called pruning, analogous to truncation of the singular-value decomposition, underlies a number of ...
    • Cost-efficient approximation of linear systems with repeated and multi-channel filtering configurations 

      Kutay, M. A.; Erden, M. F.; Ozaktas, H. M.; Arikan, O.; Candan, Ç.; Güleryüz, Ö. (IEEE, Piscataway, NJ, United States, 1998)
      It is possible to obtain either exact realizations or useful approximations of linear systems or matrix-vector products arising in many different applications, by synthesizing them in the form of repeated or multi-channel ...
    • Electromagnetic modeling of split-ring resonators 

      Gürel, L.; Ünal, A.; Ergül, Ö. (2007)
      In this paper, we report our efforts to model splitring resonators (SRRs) and their large arrays accurately and efficiently in a sophisticated simulation environment based on recent advances in the computational electromagnetics. ...
    • The fractional Fourier domain decomposition 

      Kutay, M. A.; Özaktaş, H.; Ozaktas, H. M.; Arikan, O. (Elsevier, 1999)
      We introduce the fractional Fourier domain decomposition. A procedure called pruning, analogous to truncation of the singular-value decomposition, underlies a number of potential applications, among which we discuss fast ...
    • Incomplete LU preconditioning for the electric-field integral equation 

      Malas, T.; Gürel, L. (2006)
      Linear systems resulting from the electric-field integral equation (EFIE) become ill-conditioned, particularly for large-scale problems. Hence, effective preconditioners should be used to obtain the iterative solution with ...
    • Inverse optimal control and positive real systems 

      Ünal Yılmaz (Bilkent University, 1997)
      In this thesis an inverse optimal control problem for constant output feedbacks is investigated. Necessary and sufficient conditions for optimality of an output feedback are derived for single-input, single-output systems. ...
    • Measurement strategies for input estimation in linear systems 

      Òzçelikkale, A.; Özaktas H.M.; Artkan, E. (2007)
      In this work, we present a mathematical approach for some of the measurement problems arising in optics, which is also applicable to other contexts. We see the measurement problem as the problem of determining the best ...
    • Model based anticontrol of discrete-tiime systems 

      Morgül, Ö. (Institute of Electrical and Electronics Engineers, 2003)
      We will consider a model-based approach for the anticontrol of some discrete-time systems. We first assume the existence of a chaotic model in an appropriate form. Then by using an appropriate control input we try to match ...
    • Nonlinear laser lithography for indefinitely large-area nanostructuring with femtosecond pulses 

      Öktem, B.; Pavlov, I.; Ilday, S.; Kalaycıoǧlu, H.; Rybak, A.; Yavaş, S.; Erdoǧan, M.; Ilday F. Ö. (Nature publishing group, 2013)
      Dynamical systems based on the interplay of nonlinear feedback mechanisms are ubiquitous in nature. Well-understood examples from photonics include mode locking and a broad class of fractal optics, including self-similarity. ...
    • A novel technique for a linear system of equations applied to channel equalization 

      Pilanci, M.; Arikan, O.; Oǧuz, B.; Pinar, M.Ç. (2009)
      In many inverse problems of signal processing the problem reduces to a linear system of equations. Accurate and robust estimation of the solution with errors in both measurement vector and coefficient matrix is a challenging ...
    • On Switching H ∞ Controllers for a Class of LPV Systems 

      Yan, P.; Özbay, H. (Institute of Electrical and Electronics Engineers, 2003)
      We consider switching H ∞ controllers for a class of LPV systems scheduled along a measurable parameter trajectory. The candidate controllers are selected from a given controller set according to the switching rules based ...
    • On the discrete adaptive posicast controller 

      Abidi, K.; Yildiz, Y. (IFAC Secretariat, 2015)
      In this paper, we present the discrete version of the Adaptive Posicast Controller (APC) that deals with parametric uncertainties in systems with input time-delays. The continuous-time APC is based on the Smith Predictor ...
    • On the Set of All Stabilizing First-Order Controllers 

      Saadaoui, K.; Özgüler, A.B. (2003)
      A computational method is given for determining the set of all stabilizing proper first-order controllers for finite dimensional, linear, time invariant, scalar plants. The method is based on a generalized Hermite-Bie ...
    • Parallel minimum norm solution of sparse block diagonal column overlapped underdetermined systems 

      Torun, F. S.; Manguoglu, M.; Aykanat, C. (Association for Computing Machinery, 2017)
      Underdetermined systems of equations in which the minimum norm solution needs to be computed arise in many applications, such as geophysics, signal processing, and biomedical engineering. In this article, we introduce a ...
    • Parallel preconditioners for solutions of dense linear systems with tens of millions of unknowns 

      Malas, T.; Ergül Ö.; Gürel, L. (2007)
      We propose novel parallel preconditioning schemes for the iterative solution of integral equation methods. In particular, we try to improve convergence rate of the ill-conditioned linear systems formulated by the electric-field ...
    • Parametric identification of Hybrid Linear-Time-Periodic Systems 

      Uyanık, İ.; Saranlı U.; Morgϋl, Ö.; Ankaralı, M. M. (Elsevier B.V., 2016)
      In this paper, we present a state-space system identification technique for a class of hybrid LTP systems, formulated in the frequency domain based on input-output data. Other than a few notable exceptions, the majority ...