Yazar "Akçay, Hüseyin" için listeleme
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Power Spectrum Estimation in Innovation Models by Nuclear Norm Optimization
Akçay, Hüseyin; Türkay, Semiha (IEEE Computer Society, 2018)In this paper, identification of discrete-time power spectra of multi-input/multi-output models in innovation form from output-only time-domain measurements is studied. Two regularized nuclear norm minimization-based ... -
Power spectrum estimation with missing values
Akçay, Hüseyin; Türkay, Semiha (IEEE, 2015)In this paper, we consider estimation of a power spectrum from noise corrupted spectrum samples on uniform grids of frequencies with missing values. A scheme based on regularized nuclear norm optimization and subspace ... -
Rail Track Modelling by Using Identification and Curve Fitting Techniques
Türkay, Semiha; Leblebici, Aslı Soyic; Akçay, Hüseyin (IEEE, 2018)In this paper, a seventeen-degree-of-freedom full-car model of a high speed railway vehicle excited by real track profile is going to be studied. The field measurements are collected by Turkish State Railways (TCDD) on a ... -
Rational interpolation from phase data by subspace methods
Akçay, Hüseyin (IEEE, 2010)In this paper, two simple subspace-based identification algorithms to identify stable linear-time-invariant systems from corrupted phase samples of frequency response function are developed. The first algorithm uses data ... -
Rational interpolation of analytic functions from real or imaginary parts of frequency-response data: A subspace-based approach
Akçay, Hüseyin; Türkay, Semiha (2009)In this letter, construction of analytic functions from evaluations of real or imaginary parts on finite subsets of the unit circle is studied. The points in the subsets are not necessarily uniformly spaced as in the most ... -
Regularized Nuclear Norm Spectrum Estimation in Frequency Domain
Akçay, Hüseyin; Türkay, Semiha (IEEE, 2013)Subspace-based methods have been effectively used to estimate multi-input/multi-output, discrete-time, linear-time invariant systems from spectrum samples. A critical step in these methods is the splitting of causal and ... -
RMS Performance Limitations and Constraints for Quarter-Car Active Suspensions
Akçay, Hüseyin; Türkay, Semiha (IEEE, 2008)In this paper, performance limitations and constraints for an actively controlled quarter-car model subject to white or colored-noise velocity road inputs are investigated. It is demonstrated that tire damping by coupling ... -
Road profile modeling by subspace identification methods
Türkay, Semiha; Akçay, Hüseyin (Institute of Electrical and Electronics Engineers Inc., 2015)In this paper, spectral models of road profiles using nonparametric and subspace identification methods are developed from road elevation measurements. First, power spectra of road profiles are estimated on uniform grids ... -
Road Profile Modeling by Subspace Identification Methods
Türkay, Semiha; Akçay, Hüseyin (IEEE, 2015)In this paper, spectral models of road profiles using nonparametric and subspace identification methods are developed from road elevation measurements. First, power spectra of road profiles are estimated on uniform grids ... -
Road Roughness Evaluation by Curve-Fitting and Subspace-Identification Methods
Türkay, Semiha; Akçay, Hüseyin (Asce-Amer Soc Civil Engineers, 2016)In this paper, for a quarter-car model, root-mean square response variables are calculated for roads classified by the international standard organization, based on the straight-line spectrum models. Covariance expressions ... -
Road Roughness Modelling by Using Spectral Factorization Methods
Türkay, Semiha; Akçay, Hüseyin (IEEE, 2016)In this paper, road roughness model for the right and the left tracks are constructed by utilizing two methods. In the first method, from time-domain measurements the empirical auto and cross-power spectral densities of ... -
Short-Term Wind Speed Forecasting by Spectral Analysis
Akçay, Hüseyin; Filik, Tansu (IEEE, 2018)In this paper, we apply a wind speed forecasting framework developed earlier by the authors to the two-dimensional wind velocity measurements collected from a meteorological station in the Marmara region of Turkey over a ... -
Short-term wind speed forecasting by spectral analysis from long-term observations with missing values
Akçay, Hüseyin; Filik, Tansu (Elsevier Sci LTD, 2017)In this paper, we propose a novel wind speed forecasting framework. The performance of the proposed framework is assessed on the wind speed measurements collected from the five meteorological stations in the Marmara region ... -
The size of the membership-set in a probabilistic framework
Akçay, Hüseyin (Pergamon-Elsevier Science LTD, 2004)In this paper, we study the size of the membership-set for system identification in a probabilistic framework. Assuming that the regressors are persistently exciting and the measurement noise is a sequence of independent, ... -
A spectral estimation case study in frequency-domain by subspace methods
Akçay, Hüseyin; Türkay, Semiha (IEEE, 2013)In this paper, the properties of two recently proposed frequency-domain subspace-based algorithms to estimate discrete-time cross-power spectral density (cross-PSD) and auto-power spectral density (auto-PSD) matrices of ... -
Spectral estimation in frequency-domain by subspace techniques
Akçay, Hüseyin (Elsevier Science BV, 2014)In this paper, frequency-domain subspace-based algorithms are proposed to estimate discrete-time cross-power spectral density (cross-PSD) and auto-power spectral density (auto-PSD) matrices from samples of the Welch cross-PSD ... -
Spectral Modeling of Longitudinal Road Profiles
Türkay, Semiha; Akçay, Hüseyin (IEEE, 2015)In this paper, for a quarter-car model, we derive covariance expressions for the MIRA spectrum and calculate the root-mean square outputs for the ISO 8608 classified roads. The derived results are compared with existing ... -
Spectrum estimation in frequency-domain by subspace and regularization-based algorithms: A survey
Akçay, Hüseyin (IEEE, 2015)In this survey article, we study methods to identify multi-input/multi-output, discrete-time, linear time-invariant systems from power spectrum measurements. First, we examine subspace-based identification algorithms. A ... -
Spectrum estimation in innovation models by a nuclear norm optimization based algorithm
Akçay, Hüseyin; Türkay, Semiha (IEEE, 2017)In this paper, identification of multi-input/multioutput (Ml MO) state-space models in the innovation form by a regularized-nuclear norm optimization based subspace algorithm is studied. Parametrization issues arc carefully ... -
Spectrum estimation with missing values: A regularized nuclear norm minimization approach
Akçay, Hüseyin; Türkay, Semiha (World Scientific Publ Co Pte LTD, 2016)In this paper, we consider estimation of a power spectrum from noise corrupted spectrum samples on uniform grids of frequencies with missing values. We propose two schemes based on the regularized nuclear norm minimization ...