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In this paper, the behaviour of a variable-order passive circuit element which is used in Chua chaotic circuit is analysed. Firstly, the behaviour of a circuit with a variable-order memristor is presented. In the generalized Ohm’s law for a memory element, the order of a passive circuit element is defined as a kind of the element, so the circuit shows unusual behaviour. Finally, the chaotic circuit

Normalization and envelope generation of signals are essential pre-processing steps in many signal processing applications. With the emergence of high-performance computing and the need for hardware accelerators in digital signal processing, research for hardware efficient solutions has become a necessity. Interpolation and signal normalization algorithms, though have been implemented in software systems

Energy detection-based spectrum sensing techniques are ideally suited for power-constrained cognitive radio applications because of their lower computational complexity compared to feature detection techniques. However, their detection performance is dependent on multiple factors like accuracy of noise variance estimation and signal-to-noise ratio (SNR). Many variations of energy detection techniques

Non-local mean (NLM) adaptive filtering is a well-explored technique for the denoising of images and electrocardiogram signals. In NLM filtering, the signal value at a particular sample point is estimated by a weighted average of sample points over a search neighborhood. The NLM filter effectively removes the noise when there are similarities among the samples of the signal over the search neighborhood

This paper proposes a spectrum sensing algorithm from one-bit measurements in a cognitive radio sensor network. A likelihood ratio test (LRT) for the one-bit spectrum sensing problem is derived. Different from the one-bit spectrum sensing research work in the literature, the signal is assumed to be a discrete random correlated Gaussian process, where the correlation is only available within immediate

Among other uses, oversampling can be useful for systems that aim to accurately estimate the time delay between two signals. Due to the simplicity of its implementation, \(\varSigma \varDelta \) analog-to-digital converters have been largely used when oversampled signals are required. In this work, two methods for parallel evaluation of the discrete Fourier transform (DFT) of \(\varSigma \varDelta

This paper is devoted to the problem of isomorphism in graphs and proposes a method based on time response of a differential equation. First it is shown that the solution of a differential equation obtaining from a Laplacian matrix can be used as an index and the proof is presented. Then a search algorithm is proposed to find out that the two graphs are isomorphic and there is a permutation matrix

In this paper, we aim to improve traditional DNN x-vector language identification performance by employing wide residual networks (WRN) as a powerful feature extractor which we combine with a novel frequency attention network. Compared with conventional time attention, our method learns discriminative weights for different frequency bands to generate weighted means and standard deviations for utterance-level

In this paper, we propose a configurable rotation matrix for Hyperbolic COordinate Rotation DIgital Computer (CORDIC) to compute any logarithm and inverse logarithm. The rotation matrix of the conventional Hyperbolic CORDIC computes only natural logarithm and natural inverse logarithm whereas the proposed rotation matrix configures the Hyperbolic CORDIC to compute any logarithm and inverse logarithm

In this paper, we investigate the problem of joint direction-of-departure (DOD) and direction-of-arrival (DOA) estimation for bistatic multiple-input multiple-output radar with unknown spatially colored noise. By exploiting the sparse structure of the noise covariance matrix, a new de-noising scheme is designed. The signal covariance matrix is recast as a low-rank matrix with missing entries, which

A foreground calibration technique for switched-current R-2R digital-to-analog converter is proposed. To implement the method, some intermediate nodes are added to the circuit and calibration is done using these nodes to circumvent both current source and resistor mismatches at the output node. A 12-bit, 500-MHz DAC is designed in 0.18 \(\upmu \)m standard CMOS technology with the proposed technique

Underdetermined blind source separation (UBSS) is an important issue for sparse signals, and a novel two-step approach for UBSS based on the law of large numbers and minimum intersection angle rule (LM method) is presented. In the first step, an estimation of the mixed matrix is obtained by using the law of large numbers, and the number of source signals is displayed graphically. In the second step

Image deblurring is a fundamental problem in imaging field which often needs to recover the important structure of images. This paper addresses the image deblurring problem by considering an image as a combination of its cartoon (the piecewise smooth part of the image) and texture (the oscillation part of the image) components. To recover both of these parts, we propose the use of coupled analysis-based

In this paper, we propose a novel parameter-free Landweber iteration (LI) method to improve the robustness of a beamformer based on the LI algorithm and the L-curve criterion. The critical aspect of the proposed method is the automatic parameter selection procedure, which determines the iteration stop number in a scenario-dependent manner. This parameter-free method can flexibly adapt to different

This paper investigates the finite-time robust passive control of nonlinear discrete time-delay systems via static output feedback. The considered discrete time-delay system has uncertain terms which are due to parametric uncertainties and exogenous disturbances. The disturbances are unknown time-varying signals with known upper bounds. In order to design the suitable control law, some sufficient conditions

For the problem of motion state estimation of mobile target tracked by sensor nodes, the information-weighted Kalman consensus filter (IKCF) is introduced for sensor networks with switching communication topologies. In order to improve the dynamic performance of the IKCF, the low-pass consensus filtering algorithm is used to estimate the motion acceleration of the target. Moreover, an improved low-pass

The design of filter banks with multiple centers of symmetry is very difficult. In this paper, a space decomposition of an orthogonal projection matrix is studied. This decomposition plays a key role in a new complete factorization theory. In addition, the concept of a minimal starting block matrix is proposed and is used to establish a new factorization of a 2m-band paraunitary polyphase matrix with

In this paper, the authors propose a novel model order reduction method integrating evolutionary and conventional approaches for higher-order linear time-invariant single-input–single-output (SISO) and multi-input–multi-output (MIMO) dynamic systems. The proposed method makes use of a differential evolution algorithm with enhanced mutation operation for the determination of reduced order model (ROM)

This paper extends the concept of Karnaugh map from a logical function to a logical system, thereby allowing both the state transition graph and state transition matrix of a logical system, as well as a digital circuit, to be constructed directly. It is found that the Karnaugh map of a logical system is actually a two-dimensional state transition table or, equivalently, a table-like state transition

Image segmentation is a method of subdividing an image into numerous meaningful regions or objects, which makes the image more informative and easy to analyze. Thresholding-based approaches are extensively employed for segmenting the image due to their low computational cost and are easy implementation. However, histogram-based thresholding schemes suffer from high variation that leads to abnormalities

The determination and classification of natural language based on specified content and data set involves a process known as spoken language identification (LID). To initiate the process, useful features of the given data need to be extracted first in a mature process where the standard LID features have been previously developed by employing the use of MFCC, SDC, GMM and the i-vector-based framework

This paper is concerned with the identification of turntable servo system through the usage of a reframed multi-innovation least-squares scheme. A Wiener–Hammerstein model is employed in this paper to depict the dynamic characteristics of the turntable system. In the test bed, the stabilized platform can be considered as a linear dynamic subsystem. The motor is also a linear dynamic subsystem. And

This paper proposes the realization of perceptual wavelet approximation of Bark scale using a linear-phase integer decimated non-uniform filter bank (IDNUFB), designed by merging the channels of a partially cosine-modulated uniform filter bank. In effect, the channels with different sampling factors of the IDNUFB can be derived from the same prototype filter using the proposed method of design. Also

In the recent literature, some practical systems have been modeled as interval systems. In this investigation, an improved approximation technique is first proposed for model reduction in single-input-single-output continuous interval systems; then, the proposed technique is extended to reduce multi-input-multi-output continuous interval systems. The proposed technique is based on a multipoint Padé

With the development of distributed algorithms, many researchers are committed to the goal of maintaining the long-term stability of the network by reducing the communication cost. However, many algorithms that lessen communication costs often result in a significant decrease in estimation accuracy. In order to reduce the communication cost with less performance degradation, the distributed neighbor-partial

In this paper, we propose a new family of algorithms for underdetermined blind identification based on the second generating function (SGF). For the real case, the proposed algorithm first takes advantage of the partial derivatives of the SGF of the observation signals to construct a tensor and then reconstructs this tensor by grouping the parallel factors. The reconstructed tensor, which expands the

In this paper, a low-energy switching scheme based on the asymmetric binary search algorithm for successive approximation register (SAR) analog-to-digital converters (ADCs) is proposed. To reduce switching energy and area, the proposed scheme uses the single-side switching method and the least significant bit (LSB) capacitor is split into two one-half unit capacitors. Using the series capacitance scheme

The \(l_2-l_{\infty }\) filtering problem is studied for a class of discrete-time switched systems under the admissible edge-dependent average dwell time (AED-ADT) switching. Firstly, a new multiple convex Lyapunov function (MCLF) is established as a convex combination form in the context of the \(l_2-l_{\infty }\) filtering problem. Then, corresponding to the MCLF, the quasi-time-dependent switched

Various methods have been proposed to estimate the direction of arrival (DOA) of sources under the assumption of Gaussian noise. This assumption, based on the central limit theorem, has been mainly used because it offers an appropriate model in a homogeneous environment. Nevertheless, under certain conditions, the Gaussian hypothesis cannot fully represent the noisy environment. Consequently, these

A noise optimization method for millimeter-wave RF wideband applications is reported. Intrinsic noise laws in wideband RF systems are discovered, and a noise flatness methodology based on a network quality factor algorithm is proposed. This algorithm aims to reduce the total noise in an RF system and increase the noise flatness over a full operating band. An RF wideband front end is investigated to

This paper presents a two-dimensional (2-D) eigenfilter technique to design 2-D perfect reconstruction (PR) filterbanks with directional vanishing moment (DVM). In this paper, we first introduce the DVM constraint for 2-D directional filterbank design. The proposed DVM constraint is imposed in 2-D eigenfilter formulation to obtain maximally flat 2-D low-pass analysis filter. Then, we use this designed

This paper develops a bias correction-based recursive estimation algorithm for dual-rate output-error systems. The system output is subjected to both output noise and sampling noise. Using the polynomial transformation technique, the dual-rate output-error system is converted into an identification model where the sampled data can be directly applied. The noise variances of output noise and sampling

The quaternion linear canonical transform (QLCT), as a generalized form of the quaternion Fourier transform, is a powerful analyzing tool in image and signal processing. In this paper, we propose three different forms of uncertainty principles for the two-sided QLCT, which include Hardy’s uncertainty principle, Beurling’s uncertainty principle and Donoho–Stark’s uncertainty principle. These consequences

This paper develops an efficient adaptive filtering algorithm for active impulsive noise control (AINC) systems. For AINC systems, the filtered-x least mean square (FxLMS) algorithm fails to converge due to the impulsive nature of the noise source. In previous work, the step-size of the FxLMS algorithm was normalized using the power estimate of the error as well as the reference signals, resulting

This paper presents a method for multi-speaker voiced/unvoiced decision in the case of monaural speech. This approach is based on the multi-scale product (MP) analysis of a composite signal. It consists in calculating the distances between the maxima and the minima of our proposed MP analysis technique. Then, we analyze these distances in order to make the voicing decision for both speech signals forming

Zero frequency filtering (ZFF) is a well-explored technique for detecting glottal closure instants (GCIs) from the speech signal. The features extracted from the ZFF of the speech signal have also been used for many speech-based applications. Zero frequency resonators used in the infinite impulse response (IIR) realization of ZFF are unstable filters. Consequently, the filter output grows or decays

Reconfigurability is an important capability that provides flexibility in computing architecture and low-power technique. It is challenging in digital-in-concept for designing smart analog circuits operated on low power. This work presents a low-power, low-noise, and high-speed multistage feed-forward reconfigurable comparator for medium-to-high-speed analog-to-digital converter. A power-efficient

In this paper, a novel robust Student’s t-based Kalman filter (RSTKF) is proposed to solve the problem of a linear system with heavy-tailed process and measurement noises (HPMN) and colored measurement noise (CMN). The above problem is transformed into the filtering problem of a linear system with HPMN and white measurement noise after using the measurement differencing method and state augmentation

In this paper, we develop a robust algorithm for improving the accuracy of direction-of-arrival estimation under non-Gaussian noise and insufficient sample support. (The number of sensors is large, while the number of samples is relatively small.) Unlike the traditional peak-search techniques, our approach is based on an enhanced covariance matrix estimation, where we exploit the thoughts of the M-estimator

The problem of DOA and polarization parameter estimation is considered in this paper from a perspective of sparse reconstruction. We present a novel off-grid hierarchical block-sparse Bayesian method for DOA and polarization parameter estimation to improve the estimation accuracy. Firstly, an off-grid model is formulated via the first-order Taylor expansion of the source steering vector. Then, a block-sparse

This paper presents a new on–off keying modulation circuit for a Class-E power transmitter used in high-data-rate wireless links used for powering medical implants. A circuit technique is proposed to keep the current of the RF choke of the power transmitter constant, while the transmitter turns on and off. This allows the transmitter to quickly turn on and off. To prove the feasibility of the proposed

This paper presents a novel simple 4-D dissipative autonomous hyperchaotic system with a saddle-point index-2 equilibrium point. The dynamics of the new system consists of nine terms with two nonlinear terms. Thus, the proposed system is one of the simplest 4-D hyperchaotic systems. The new system also shows multistability behavior for some range of its parameters. Bifurcation diagrams, Lyapunov spectrum

This paper presents a novel architecture for phase frequency detector (PFD) which eliminates the blind zone effect as well as the dead zone for a charge-pump phase-locked loop (CP-PLL). This PFD is designed in 65 nm CMOS technology, and its functionality is verified across process, voltage and temperature variations. Achieved maximum frequency of operation (\(F_{\max }\)) is 3.44 GHz which is suitable

The modified filtered-x affine projection (MFxAP) algorithm is effective for active noise control owing to its good convergence behavior and medium computational burden. The transient and steady-state performances of the MFxAP algorithm have been analyzed in previous studies, which presented a relatively good agreement between the theory and measured results. However, the correlation between the weight-error

A subspace-based deterministic identification method is proposed for MIMO linear systems with time delay in their state variables. This method can estimate the matrices of the state-delayed system, its order and the amount of time delay. First, by extending the orthogonal decomposition subspace method for state-delayed systems, the augmented system matrices which include the original system matrices

To better capture the phase information of single-phase power grids, a novel single-phase phase-locked loop method is proposed in this paper. The method uses a tracking differentiator as an orthogonal signal generator. Because the generator is sensitive to the input signal’s frequency, the amplitudes of the tracking and differential signals may not be equivalent, causing a failed phase tracking. Therefore

This paper addresses the joint time difference of arrival (TDOA), frequency difference of arrival (FDOA) and differential Doppler rate estimation problem for high-speed maneuvering targets in passive location systems, involving linear range migration (LRM), quadratic range migration (QRM) and linear Doppler frequency migration (LDFM) within observation time. A noise-resistant estimation algorithm based

Robust principal component analysis (RPCA) has recently seen ubiquitous activity for dimensionality reduction in image processing, visualization and pattern recognition. Conventional RPCA methods model the low-rank component as regularizing each singular value equally. However, in numerous modern applications, each singular value has different physical meaning and should be treated differently. This

This paper aimed at investigating the exponential synchronization problem for a Markovian jump complex dynamical network through designing a state feedback controller. In this paper, it is supposed that both time delay and coefficient matrices switch between finite modes governed by a time-varying Markov process. The transition rate (TR) matrix of the Markov process is supposed to vary with time, and

This paper studies adaptive radar detection of a subspace signal embedded in two disturbance sources. The former is thermal noise with known power. The latter is a Gaussian subspace interference with zero mean and unknown covariance matrix (CM). It is assumed that the signal and interference subspaces are known and partially related. As customary, several secondary data containing only interference

In the recent years, extensive researches have been performed on various possible implementations of speaker diarization systems. These systems require efficient clustering algorithms in order to improve their performances in real-time processing. Teaching–learning-based optimization (TLBO) is such clustering algorithm which can be used to resolve the problem to the optimum clustering in a reasonable

In this study, a novel synthetic transformer (ST), namely mutually coupled circuit, using commercially available active components such as current feedback operational amplifiers (CFOAs) is proposed. The proposed ST uses four CFOAs, two grounded capacitors and five resistors. It possesses only resistors but no capacitors attached in series to W/X terminals of the CFOAs; consequently, its high-frequency

This work aims to study the problem of output strictly passive \(H_\infty \) control for discrete-time linear switched singular systems. By using multiple storage functions and iteration technique, some sufficient conditions are obtained based on output strict passivity and proportional plus derivative state feedback, which can guarantee that the closed-loop systems are normal and stable and satisfy

The problem of joint angle and frequency estimation is considered in this paper. An algorithm using spatial–temporal nested sampling and one-bit quantization is developed. It is shown that under moderate condition when the signal-to-noise ratio is low enough, the defined one-bit correlation matrix has linear relationship with the unquantized one, and therefore, subspace-based algorithms can be applied

Electrocardiogram (ECG) is one of the major methods for the diagnosis of heart malfunctions. ECG signals are susceptible to both high-frequency and low-frequency noises such as electromyography (EMG), power line interference (PLI) and baseline wander noises, respectively. These noises deteriorate the quality of ECG signals and challenge the proper identification of heart illnesses. In this article

This paper proposes an audio multi-watermarking scheme based on Gram–Schmidt orthogonalization. A random signal generator is applied to the host audio signal to generate the target segment for the local watermarking, thus improving the imperceptibility compared with the conventional global watermarking. The discrete cosine transform low-frequency coefficients of high stability are selected as watermark

In the past years, several QRS complex (Q, R and S wave) detecting algorithms have been implemented in software, but they are not applicable for real-time operation due to their mathematical complexity. Hence, this paper focuses on developing an algorithm which enables detection of QRS complex in real time. Here, Integer Haar Wavelet Transform is employed which is used for the purpose of filtering

There are DAC structures available in the literature for radix r = 2, 3 and 4, but how they are arrived at is missing. Author’s generalized DAC of any radix reported recently removes this gap, but requires r − 2 references sources. This paper gives three methods of replacing all the reference sources, except one. Comparison of all the three methods is given.

To reduce the computational complexity and enhance the convergence rate, this article presents set-membership least mean square adaptive algorithms based on an error-estimation time-varying bound method. The bound is constituted by the estimation error for the previous iteration and a time-varying error adjustment factor. The set-membership (SM) method utilizes the estimation error for the current