Differential Filter Research Articles

Non-Destructive Methodology to Determine Modulus of Elasticity in Static Bending of Quercus mongolica Using Near-Infrared Spectroscopy.

This article presents a non-destructive methodology to determine the modulus of elasticity (MOE) in static bending of wood through the use of near-infrared (NIR) spectroscopy. Wood specimens were obtained from Quercus mongolica growing in Northeast of China. The NIR spectra of specimens were acquired by using a one-chip NIR fiber optic spectrometer whose spectral range was 900~1900 nm. The raw spectra of specimens were pretreated by multiplication scatter correlation and Savitzky-Golay smoothing and differentiation filter. To reduce the dimensions of data and complexity of modeling, the synergy interval partial least squares and successive projections algorithm were applied to extract the characteristic wavelengths, which had closing relevance with the MOE of wood, and five characteristic wavelengths were selected from full 117 variables of a spectrum. Taking the characteristic wavelengths as input values, partial least square regression (PLSR) and the propagation neural network (BPNN) were implemented to establish calibration models. The predictive ability of the models was estimated by the coefficient of determination (rp) and the root mean square error of prediction (RMSEP) and in the prediction set. In comparison with the predicted results of the models, BPNN performed better results with the higher rp of 0.91 and lower RMSEP of 0.76. The results indicate that it is feasible to accurately determine the MOE of wood by using the NIR spectroscopy technique.

Simulasi dan Analisa Performansi Buck Converter Dengan Pengendali Dua Derajat Kebebasan

DC power supply are commonly used to convert DC voltage level to another level. One type of DC power supply is a buck converter that is used to lower a voltage level. In order to have a proper feedback of voltage output in buck converter system, it will be controlled by a Two Degrees of Freedom PID Controller. This research aim to analyze the performance of the buck converter that have a Two Degrees of Freedom PID Controller. Two Degrees of Freedom Controller has proportional, integral and derivative control parameters. The simulation of the system is made with the help of software MATLAB. The first simulation and analysis is buck converter system without controller. From the analysis, the desired criteria is obtained . Then a buck converter system was designed. It is controlled using a parallel type of Two Degrees of Freedom PID Controller as well as feedforward, feedback, and filter. From all these types of controllers, it showed that the first order of Proportional Differential Filter (PDF) feedforward type with the value of Kp = 171, Kd = 0.00545, Tf = 4.88e-07 and the first order of PDF feedback type with the value of Kp = 171, Kd = 0.00545, Tf = 4.88e-07 was considered as the proper controller that matched with the characteristic. Therefore, it could be concluded that the buck converter controlling system with Two Degrees of Freedom PID Controller could produce a buck converter system with a good performance compared to buck converter without any controllers. Keywords: Buck converter, Two Degrees of Freedom PID Controller, control system, time domain performance .

Alexander fractional differential window filter for ECG denoising.

The electrocardiogram (ECG) non-invasively monitors the electrical activities of the heart. During the process of recording and transmission, ECG signals are often corrupted by various types of noises. Minimizations of these noises facilitate accurate detection of various anomalies. In the present paper, Alexander fractional differential window (AFDW) filter is proposed for ECG signal denoising. The designed filter is based on the concept of generalized Alexander polynomial and the R-L differential equation of fractional calculus. This concept is utilized to formulate a window that acts as a forward filter. Thereafter, the backward filter is constructed by reversing the coefficients of the forward filter. The proposed AFDW filter is then obtained by averaging of the forward and backward filter coefficients. The performance of the designed AFDW filter is validated by adding the various type of noise to the original ECG signal obtained from MIT-BIH arrhythmia database. The two non-diagnostic measure, i.e., SNR, MSE, and one diagnostic measure, i.e., wavelet energy based diagnostic distortion (WEDD) have been employed for the quantitative evaluation of the designed filter. Extensive experimentations on all the 48-records of MIT-BIH arrhythmia database resulted in average SNR of 22.014 ± 3.806365, 14.703 ± 3.790275, 13.3183 ± 3.748230; average MSE of 0.001458 ± 0.00028, 0.0078 ± 0.000319, 0.01061 ± 0.000472; and average WEDD value of 0.020169 ± 0.01306, 0.1207 ± 0.061272, 0.1432 ± 0.073588, for ECG signal contaminated by the power line, random, and the white Gaussian noise respectively. A new metric named as morphological power preservation measure (MPPM) is also proposed that account for the power preservance (as indicated by PSD plots) and the QRS morphology. The proposed AFDW filter retained much of the original (clean) signal power without any significant morphological distortion as validated by MPPM measure that were 0.0126, 0.08493, and 0.10336 for the ECG signal corrupted by the different type of noises. The versatility of the proposed AFDW filter is also validated by its application on the ECG signal from MIT-BIH database corrupted by the combination of the noises as well as on the real noisy ECG signals are taken from MIT-BIH ID database. Furthermore, the comparative study has also been done between the proposed AFDW filter and existing state of the art denoising algorithms. The results clearly prove the supremacy of our proposed AFDW filter.

Microstrip differential passband filter with high common‐mode suppression using periodically loaded stubs and coupled resonators

In this study, a periodic structure as a passband filter for differential input signals is introduced that suppresses the common-mode noise with a high common-mode rejection ratio on a wide range of frequencies. The unit cell of the periodic structure consists of open-ended stubs under common-mode and short-ended stubs under differential-mode excitation. The proposed design procedure introduced in this paper can be exploited for different microwave frequency bands while the overall shape of the filter remains unchanged. To verify the design approach, the authors designed and fabricated a filter at the centre frequency of 7 GHz on a Rogers RO4003 substrate with a dielectric constant of 3.7 and a loss tangent of 0.0027. Their studies show that for a three-unit-cell structure with the overall size of 18 mm × 40 mm (0.75λ g × 1.66λ g), a differential fractional bandwidth of 8.6% and a rejection ratio over 55 dB are achieved while the differential in band insertion loss is around 2 dB.

Low-Loss Directional Filters Based on Differential Band-Reject Filters With Improved Isolation Using Phase Inverter

In this letter, a novel approach to the design of directional filters (DFs) based on the differential bandstop filter and delay lines is proposed. It is shown that utilization of a phase inverter (PI) and reference line as a mode-converting phase shifter allows for obtaining theoretically ideal bandpass-to-bandstop channels isolation over an infinite bandwidth. The presented theoretical analysis is confirmed by realization of an exemplary low-loss DF with defected ground type PI covering industrial, scientific, and medical, 2.4-GHz band. The obtained measurement results show insertion loss as low as 1.1 dB and almost flat isolation response, better than 27 dB up to 6 GHz proving the validity of the presented approach.

Topology optimization of finite strain viscoplastic systems under transient loads

SummaryA transient finite strain viscoplastic model is implemented in a gradient‐based topology optimization framework to design impact mitigating structures. The model's kinematics relies on the multiplicative split of the deformation gradient, and the constitutive response is based on isotropic hardening viscoplasticity. To solve the mechanical balance laws, the implicit Newmark‐beta method is used together with a total Lagrangian finite element formulation. The optimization problem is regularized using a partial differential equation filter and solved using the method of moving asymptotes. Sensitivities required to solve the optimization problem are derived using the adjoint method. To demonstrate the capability of the algorithm, several protective systems are designed, in which the absorbed viscoplastic energy is maximized. The numerical examples demonstrate that transient finite strain viscoplastic effects can successfully be combined with topology optimization.

Molecular and Bioinformatics Analyses Identify 7 Circular RNAs Involved in Regulation of Oncogenic Transformation and Cell Proliferation in Human Bladder Cancer.

BackgroundCircular RNAs (circRNAs) have emerged as important regulators in carcinogenesis and metastasis. However, the knowledge of circRNAs in bladder cancer remains limited. This study aimed to investigate the role and mechanism of circRNAs in the development and progression of bladder cancer.Material/MethodsThree pairs of bladder carcinomas (including high- and low-grade tumors) and adjacent normal tissues were collected from patients. The total RNAs were extracted from these samples and subjected to Clariom D microarray assays to detect the differentially expressed circRNAs and mRNAs. The mRNA targets for these circRNAs were predicted by miRanda in combination with stringent differential mRNA filters. The interaction network for the circRNA-mRNA pairs was generated by Cytoscape.ResultsAmong the 1038 circRNAs detected by the Clariom D microarray assay, we identified 7 significantly differentially expressed circRNAs in the tumors (fold change >2, FDR <0.05). Principal component analysis of the differential circRNAs confirmed that the tumor samples were separated from the normal samples. Hierarchical clustering analyses on these RNAs and their predicted mRNA targets showed that the majority of differentially expressed circRNAs and mRNAs had been up-regulated in the bladder tumors. KEGG signaling pathway analysis has indicated that genes involved in cell proliferation, oncogenic transformation, and metastasis are potentially regulated by these circRNAs.ConclusionsThe current study provides a molecular basis for further investigating the mechanisms by which circRNAs regulate bladder cancer. The clinical significance of the identified circRNAs is highlighted by their potentials as diagnostic and prognostic biomarkers for bladder cancer patients.

Low‐loss and highly‐selective differential bandpass filter on integrated passive device process

AbstractThis letter presents a low‐loss and highly‐selective differential bandpass filter (BPF) with high common‐mode rejection ratio (CMRR). The presented integrated passive device process provides high quality lumped elements, and therefore a low insertion loss of the BPF can be obtained. The circuit also uses series‐shunt resonators for controlling its differential‐ and common‐mode transmission zeros. Moreover, with a proper choice of circuit component values, a high common‐mode rejection can be controlled at a specific frequency without alternating properties of the filter. The chip area of the filter is 3.74 mm2 including all testing pads. Additionally, the differential BPF achieves a 1.5‐dB insertion loss and 11‐dB return loss with a 73% 3‐dB bandwidth at 2.2 GHz. Finally, the peak CMRR at the frequency of interest is up to 50 dB.

Design of Compact Coaxial-Like Bandpass Filters Using Dielectric-Loaded Strip Resonator

This paper presents a novel dielectric-loaded strip resonator (DLSR) with coaxial-like characteristic, comprising a metal strip attached on the surface of a high-permittivity dielectric rod. The strip of traditional strip-loaded dielectric resonator only functions as the perturbation for tuning the dielectric resonator mode. In particular, the dominant mode of the proposed DLSR stems from the strip and works as a quasi-λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> /4 resonator. It possesses very low resonant frequency with immense design freedom. The corresponding characteristics and frequency expressions of the strip mode are theoretically deduced and verified on the basis of the E-field distribution of the DLSR. For demonstration, a variety of single-ended inline filters are exploited using single-strip DLSRs with different deployments as well as the generation mechanism of transmission zeros is investigated. Furthermore, a simple modification with twin strips can serve for electrically small differential topology, highlighting the versatile design of the DLSR. Besides desirable differential-mode (DM) response, the differential DLSR filter manifests a large deviation between DM and common-mode (CM) frequencies, resulting in a satisfactory CM suppression in the DM passband. Good agreement between the simulation and the measurement validates the proposed methodology.

Wide digitally tunable lowpass filter for biomedical and wireless applications

A fully differential Gm-C lowpass filter for wireless and biomedical applications is introduced in this Letter. The proposed filter is based on a highly linear CMOS digital programmable operational transconductance amplifier (DPOTA).The filter consists of a parallel connection of three fourth-order Butterworth sections. Each section is optimised for a specific band of frequencies which can be tuned digitally. Switching between the different sections is achieved by controlling the corresponding DPOTAs' transconductance values, hence, this filter design eliminates the need for switches. Simulation results for a 90 nm CMOS technology are given. The third-order harmonic distortion (HD3) of the DPOTA remains below −60 dB up to 0.5 V differential input voltage at 1.2 V supply voltage. The proposed filter exhibits a wide cutoff frequency tuning range, from 100 Hz to 12 MHz, thus it covers many biomedical and wireless communication standards.

Differential Bandpass Filters Based on Dumbbell-Shaped Defected Ground Resonators

This letter presents a dumbbell-shaped defected ground resonator and its application in the design of differential filters. The operation principle of the dumbbell-shaped resonator (DSR) coupled to differential microstrip lines is studied through a circuit model analysis. The proposed circuit model is validated through the comparison with the electromagnetic simulation results. It is shown that the bandpass configuration of microstripline- coupled DSR can be used to design higher order bandpass filters. The design procedure is explained by developing a thirdorder filter prototype. The designed filter shows more than 57 dB common mode rejection within the differential passband.

Robust adaptive output feedback tracking control for flexible-joint robot manipulators based on singularly perturbed decoupling

SUMMARYThis paper presents a robust adaptive output feedback tracking controller for the flexible-joint robot manipulators to deal with the unknown upper bounds of parameter uncertainties and external disturbances. With applying the singular perturbation theory and integral manifold concept, the complex nonlinear coupled system of the flexible-joint robot manipulators is divided into a slow subsystem and a fast subsystem. A robust adaptive control scheme based on an improved linear parameterization expression is designed for the slow subsystem, and a saturation function is applied in the robust control term to make the torque output smooth. In the meantime, different from the previous approaches, the second-order derivative term of elastic torque is avoided by using the proposed computed torque method, which simplifies the implementation of the fast control law. Moreover, to carry out the whole control system with only position measurements, an approximate differential filter is involved to generate pseudo velocity signals for links and joint motors. In addition, an explicit but strict stability proof of the control system based on the theory of singularly perturbed systems is presented. Finally, simulation results verify the superior dynamic performance of the proposed controller.

Configuration for Realizing a Push-Push Parallel-Feedback Oscillator Through a Differential Bandpass Filter

A push–push parallel-feedback oscillator constructed through a differential bandpass filter (BPF) is investigated in this paper. For the first time, the differential filter has been utilized as the parallel-feedback element to provide differential outputs in designing the push–push oscillator. Low phase noise performance and easy design process can be obtained due to the parallel feedback circuits compared with series feedback ones. The complex quality factor ( $Q_{\textrm {sc}}$ )-peak frequency of the BPF is chosen as the half final output frequency to further improve the phase noise performance. Also, the improvement of the odd harmonic suppression and even harmonic enhancement can be easily obtained. Moreover, due to the existence of the common mode suppression, only 180° out-of-phase mode will be achieved which makes the oscillator run in a stable condition. To validate the design concept, a push–push oscillator based on a microstrip differential BPF has been achieved which is operating at 8.37 GHz. The measured results show that the output power is −5.4 dBm with a phase noise of −134.6 dBc/Hz at 1-MHz offset.

Target Tracking Based on Incremental Center Differential Kalman Filter With Uncompensated Biases

To mitigate the negative effects of the sensor measurement biases for the maneuvering target, a novel incremental center differential Kalman filter (ICDKF) algorithm is proposed. Based on the principle of independent incremental random process, the incremental measurement equation is modeled to preprocess the sensor measurement biases. Then, a general ICDKF algorithm is proposed by augmenting the process and measurement noises into the state vector to mitigate the negative effects of the sensor biases. For the system with additive noises, an additive ICDKF algorithm is derived by introducing the incremental measurement equation to reduce the measurement biases. Numerical simulations for four types of sensor biases are designed to demonstrate that the proposed ICDKF can effectively mitigate the measurement biases compared to the CDKF.

Independently Tunable/Controllable Differential Dual-Band Bandpass Filters Using Element-Loaded Stepped-Impedance Resonators

This paper presents a new approach for designing differential bandpass filter (BPF) with independently tunable/controllable dual passbands using the element-loaded stepped-impedance resonators (SIRs). The frequency-agile ability of the fundamental and third-harmonic resonant frequencies ( $f_{1}$ and $f_{3})$ of the element-loaded SIR against the value of the loaded element under different loading positions on the SIR is theoretically analyzed. It can be found that there must be a position that could be utilized to load element to realize the independent control of $f_{1}$ without affecting $f_{3}$ . This feature is successfully applicable to design independently tunable differential dual-band BPF when the loaded elements are tunable capacitors. Furthermore, by making the loaded elements to be shunt stubs, a new coupling path can be constructed for $f_{1}$ , and then the coupling coefficients for the two bands can be separately varied. Both the operational frequencies and bandwidths of the two bands can be separately adjusted. As a result, the traditional design procedure for the differential dual-band BPF can be simplified significantly. For demonstration, two examples are designed, implemented, and measured, and their simulation and measured results are presented, showing good accordance.

Compact differential bandpass filter using one-sixth mode and novel one-third mode triangular SIW resonators

Compact differential bandpass filter using one-sixth mode and novel one-third mode triangular SIW resonators

Magnetoencephalogram recording during simulated driving: Towards an ecologically-valid paradigm

Magnetoencephalogram recording during simulated driving: Towards an ecologically-valid paradigm

Compact Dual-Band Differential Bandpass Filter Using Quadruple-Mode Stepped-Impedance Square Ring Loaded Resonators

In this paper, a new quadruple-mode stepped-impedance square ring loaded resonator (SI-SRLR) is proposed, and a high-performance dual-band differential bandpass filter (BPF) is developed. Resonant characteristics of the SI-SRLR are investigated by the even-/odd-mode method and simulation techniques. Two differential-modes (DMs) of the SI-SRLR are used to form the dual differential passbands. The admittance ratio $K$ of the SI-SRLR is chosen appropriately to prevent the common-mode (CM) interference with DM operations. Moreover, an open-circuited stub is added to enhance the CM suppression, while a source-load coupling is introduced to produce multiple transmission zeros and improve significantly the frequency selectivity of DM passbands. Finally, a dual-band differential BPF is designed, fabricated, and measured. Good agreement between the simulated and measured results verifies well the proposed structure and design method.

Electrocardiogram analysis using the multi-scale Savitzky-Golay differential filter

Electrocardiogram analysis using the multi-scale Savitzky-Golay differential filter

RETRACTED ARTICLE: Edge detection of satellite image using fuzzy logic

Edge detection plays an important role in the field of image processing. Various edge detection techniques are obtained like Sobel, PSO Preweitt, Laplacian and Laplacian of Gaussian. These techniques consume some restrictions such as fixed edge thickness and some parameter like threshold is problematic to implement. Although many different edge-detection methods have been proposed for gray-scale, color, and multispectral images, they still face difficulties when extracting edge features from hyperspectral images (HSIs) that contain a large number of bands with very narrow gap in the spectral domain. High performance computing (HPC) is a technique used to assemble process and analyze more quantity of remote sensing (satellite) data which needs less processing time. HPC method is used in distributed & cluster Computing, parallel computing and following satellite data analyzing & processing approaches like geo-referencing, image edge detection, image classification, image mosaicking, Morphological/neural approach and image fusion for hyperspectral satellite data. Stimulated by means of the specific clustering of theory called gravitational theory, an original edge detection process. The conservative methods include the usage of linear time invariant filters. Recognition of edge is done by these filters as a These filters recognize an edge as a sudden conversion of grey scale pixel intensity. These techniques are well recognized and computationally effective. Canny, Sobel, Robert, Kirsch, Prewitt and LOG, on idea of spatial differential filters by using local grade. Within the less time these filters process the data and are inclined to noise. But in fuzzy technique, it does not include like this restriction, by altering the rules and output parameters, it is possible to change the thickness of the edge. In this paper, a new technique is created on fuzzy logic, which is suggested for detection of edge in digital images deprived of finding the threshold value. This method starts through segmenting the images into sections by means of fluctuating 3 $$\times $$ 3 binary matrixes. The pixels of edge are planned to a range of standards separated from each other. The results of this proposed technique is compared with the results obtained from PSO and neural network methods. This suggested technique provides a permanent effect in the lines smoothness and straightness for the straight lines and good roundness for the curved lines. And sharpness in the curves.