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26th IEEE Signal Processing and Communications Applications Conference, SIU 2018; Altın Yunus Resort ve Thermal Hotel, Izmir; Turkey; 2 May 2018 through 5 May 2018, Previously, the concept of Pilot Assisted Synchronization (PAS) and Fractional Lower Order Covariance (FLOC) has been incorporated together to synchronize alpha-stable noise based communication system which gave birth to Synchronized Random Communication Systems (SRCS). In this paper, an optimization criterion, i.e. FLOC Margin, has been proposed to improve the efficiency of the Fractional Lower Order Covariance based Correlators (FLOCCs) at the receiver side, hence, resulting in enhanced Bit Error Rate (BER) performance of SRCS. Since, the characteristic exponent and impulsiveness parameter are mainly responsible in generating and shaping up the required pilot sequence, therefore, the effects of these parameters on BER performance has also been observed by fluctuating them in their respective ranges. It has been shown that the proposed optimization criterion increases the BER efficiency of SRCS and also reveals the specific range of the characteristic exponent and impulsiveness parameter which can be exploited to achieve the optimum performance.

24th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2017; Hilton BatumiBatumi; Georgia; 5 December 2017 through 8 December 2017, In this study, we investigate the changes in the dynamics of generalized Chua's circuit through a-stable Levy noise in the framework of stochastic bifurcation concept. By choosing the noise intensity, characteristic exponent (impulsiveness parameter) and the skewness parameter of the a-stable Levy noise as the bifurcation parameters we have observed the qualitative changes in the stationary probability distributions and in the structures of the stochastic attractors.

The digital communication system is based on the skewed alpha-stable ([Formula: see text]-stable) noise sequence which is chosen as the random carrier to modulate the binary message at the transmitter side. Antipodal characteristic of the skew parameter beta ([Formula: see text]) is exploited for decoding information at the receiver side to obtain a secure communication system. A fast estimator used in this paper is based on Modified Extreme Value Method (MEVM) to extract the binary message from the signal received through the Additive White Gaussian Noise (AWGN) channel. Our proposed receiver is achieving better bit error rate (BER) versus Mixed Signal to Noise Ratio (MSNR) than previously introduced receivers which are based on Sinc and Logarithmic estimators. MEVM estimator is indeed less complex compared to the Sinc and Logarithmic estimators and hence more fast. Additionally, the criterion to measure the security level of random communication system, which is based on [Formula: see text]-stable noise sequence, has also been introduced.

The system modelling and the circuit implementation of the nonlinear circuits using the wavelet domain techniques has been accomplished in this study. When the time-frequency domain specifications have been given as the wavelet ridges, the signal with the given ridges, has been synthesized. Then, the dynamical wavelet network has been trained for the synthesized signal. The circuit of the wavelet network has been designed and simulated. (c) 2007 Elsevier GmbH. All rights reserved.

In this paper, the nonstationary signals have been recovered using the skeleton along the wavelet ridges in the noisy case and the attractors of the cleaned signals are reconstructed in the phase space by time-delay embedding. In order to verify the signal recovery and reconstruction procedure, the similarity measure Hausdorff distance between cleaned, noise-free original attractors have been calculated. The computations show that the procedure reduces the noise level acceptably and the reconstructed attractors are more similar to the original attractors.

The ridges obtained from chaotic signals can give the relevant information about the phase structures of the dynamical systems. Therefore, a new wavelet ridge determination method for the noisy signals and nonstationary signals, which is based on the singular value decomposition (SVD) has been proposed in this paper. The proposed method has been compared with Carmona method for monocomponent signals, and multicomponent signals. The proposed method is computationally more effective than the Carmona method to determine the actual ridges. Also, the ridges of the periodic limit cycles and chaotic attractors have been determined by using the SVD-based method to find the degree of chaoticity.

The time-varying frequency structure of musical signals have been analyzed using wavelets by either extracting the instantaneous frequency of signals or building features from the energies of sub-band coefficients. We propose to benefit from a combination of these two approaches and use the time-frequency domain energy localization curves, called as wavelet ridges, in order to build features for classification of musical instrument sounds. We evaluated the representative capability of our feature in different musical instrument classification problems using support vector machine classifiers. The comparison with the features based on parameterizing the wavelet sub-band energies confirmed the effectiveness of the proposed feature. © 2011 Springer Science+Business Media, LLC.

Music information retrieval and particularly musical instrument classification has become a very popular research area for the last few decades. Although in the literature many feature sets have been proposed to represent the musical instrument sounds, there is still need to find a superior feature set to achieve better classification performance. In this paper, we propose to use the parameters of skewed alpha-stable distribution of sub-band wavelet coefficients of musical sounds as features and show the effectiveness of this new feature set for musical instrument classification. We compare the classification performance with the features constructed from the parameters of generalized Gaussian density and some of the state-of-the-art features using support vector machine classifiers.

In this paper, the continuous time wavelet entropy (CTWE) of auditory evoked potentials (AEP) has been characterized by evaluating the relative wavelet energies (RWE) in specified EEG frequency bands. Thus, the rapid variations of OWE due to the auditory stimulation could be detected in post-stimulus time interval. This approach removes the probability of missing the information hidden in short time intervals. The discrete time and continuous time wavelet based wavelet entropy variations were compared on non-target and target AEP data. It was observed that CTWE can also be an alternative method to analyze entropy as a function of time. (C) 2009 Elsevier Ltd. All rights reserved.

ECCTD 2009 - European Conference on Circuit Theory and Design Conference Program; Antalya; Turkey; 23 August 2009 through 27 August 2009, In this study, the synchronization of the master-slave systems has been achieved and implemented on Field Programmable Gate Array (FPGA). In this paper, the master system and the slave system have been chosen as Lorenz and Rossler systems, respectively. The feedback control rule has been derived by feedback linearization method. By feedback linearization, the coordinate transformation has been achieved then the control command for synchronization has been obtained. In order to implement designed synchronized system, Matlab Simulink design of the system has been translated to Xilinx System Generator design to generate Very-High-Speed Integrated Circuits Hardware Description Language (VHDL) code which is used to produce bitstream file. By Xilinx Integrated Software Environment (ISE) program, VHDL code is converted to bitstream file which has been embedded into FPGA by Field Upgradeable Systems Environment (FUSE). Finally, the designed synchronized system has been observed on the HP 54540C oscilloscope.

In this paper, the probability density functions (PDFs) of the states of Generalized Chua's Circuit (GCC) have been modeled by Finite Mixture α-Stable (FMαS) distributions which is a Bayesian mixture model of α-stable distributions and it provides semiparametric characterization for the distributions of multiscroll chaotic attractors. Fully Bayesian approach has been applied to estimate the mixture parameters of multimodal distributions corresponding to the multiscroll chaotic attractors.

The stationary state probability densities appear not only in the study of dynamical systems with random vector fields, but also in the deterministic dynamical systems exhibiting chaotic behavior when the uncertainties in the initial conditions are represented with the probability densities. But since it is very hard problem to determine these densities, in this paper the new efficient method to obtain an approximate solution of Fokker-Planck-Kolmogorov equation which arises in the determination of the stationary state probability densities has been given by representing the densities with compactly supported functions. With specific choice of the compactly supported functions as piecewise multivariable polynomials which are supported on the ellipsoidal regions, the parameters to be calculated for determining the densities can be considerably decreased compared to Multi-Gaussian Closure scheme, in which the stationary densities are assumed to be the weighted average of the Gaussian densities. The main motivation to choose the compactly supported functions is that, in the chaotic dynamics the states are trapped in a specific compact subspace of the state space. The stationary state densities of two basic examples commonly considered in the literature have been estimated using the Parzen's estimator, and the densities obtained using the newly proposed method have been compared with these estimated densities and the densities obtained with the Multi-Gaussian Closure scheme. The results indicate that the presented compactly supported piecewise polynomial scheme can be successful compared to Multi-Gaussian scheme, when the system is highly nonlinear., Research Council KUL: GOA-AMBioRICS, CoE EF/05/006 Optimization in Engineering, Flemish Government: FWO: G.0211.05 (Nonlinear Systems), G.0226.06 (Cooperative Systems) Belgian Federal Science Policy Office IUAP P5/22 and Turkish Scientific Research and Development Council.

In this paper, the harmonic balance analysis of Generalized Chua's circuit exhibiting n-scroll attractors has been accomplished. The dual-input describing functions of the piecewise-linear characteristics of Chua's diode have been obtained and based on the harmonic balance principle, the existence and the locations of the n-scrolls have been verified.

A dynamic wavelet network circuit implementation for modelling the nonlinear dynamical networks has been proposed in this study. The dynamical wavelet network includes static wavelet network with Mexican hat wavelet function, the voltage-controlled switches and capacitors. The circuit simulations have been done in Spice for the period-1 limit cycle, the spiral and double scroll attractors of the Chua's circuit. (c) 2005 Elsevier GmbH. All rights reserved.

A wavelet network circuit implementation for Mexican Hat mother wavelet has been proposed for nonlinear function approximation which can also be used for the realization of the algebraic nonlinear components. The Mexican Hat mother wavelet function has been implemented with discrete circuit components and it has been observed that the experimental waveform obtained from the realized circuit is approximately same as the Spice simulation of the original function. The circuit simulations of exemplar functions implemented in Spice are also given. (C) 2004 Elsevier GrnbH. All rights reserved.

IEEE International Symposium on Circuits and Systems 2005, ISCAS 2005; Kobe; Japan; 23 May 2005 through 26 May 2005, In this paper, obtaining approximate solution of Fokker-Planck-Kolmogorov (FPK) Equation using compactly supported functions has been discussed. With specific choice of such functions as piecewise multivariable polynomials which are supported on ellipsoidal regions, the parameters to be determined can be considerably decreased compared to Multi- Gaussian Closure scheme [1]. An example commonly considered in the literature has been analyzed and the proposed method has been compared with the Multi-Gaussian Closure scheme. The simulation results indicate that the new scheme is quite successful even if the driving noise is not white Gaussian, but has an exponential correlation function with small correlation time.

In this paper, an algorithm which performs the singular values decomposition of a noisy matrix has been presented in order to make noise reduction by rank estimation of the noise free data matrix. In this study the rank estimation methodis done by finding ratios of among all consecutive singular values and selecting the maximum of these ratios as the noise threshold.

In this paper, nonlinearly coupled identical Chua's circuits, when driven by sinusoidal signal have been analyzed in the time-domain by using the steady-state analysis techniques of piecewise-linear dynamic systems. With such techniques, it has become possible to obtain analytical expressions for the transfer functions in terms of the circuit parameters. The proposed system under consideration has also been studied by analog simulations of the overall system on a hardware realization using off-the-shelf components as well as by a time-domain analysis of the synchronization error.

This paper describes the analog synthesis of a wavelet function approximator using sigmoidal mother wavelet. Any finite energy multivariate function can be approximated by this analog circuit using the multiresolution approximation property of the wavelet decomposition. The approximator circuit includes bipolar junction transistors, operational amplifiers and linear passive circuit elements.

n this paper, first the probability density functions (PDFs) of the states of Chua's circuit have been estimated using B-spline functions and then the state entropies of Chua's circuit with respect to the bifurcation parameter have been obtained. The results of the proposed B-spline density estimator have been compared with the results obtained from the Parzen density estimator. © 2012 World Scientific Publishing Company.

The parameter of the stable non-Gaussian noise sequence is modulated by the binary message sequence to achieve a secure communication system. The characteristic exponent 'alpha' of a stable non-Gaussian noise sequence carries the binary information. The receiver of the proposed random communication system demodulates the received signal by estimating the parameters of the transmitted noise sequence to recover the binary message sequence.