Output Amplitude Research Articles

Distributionally Robust Stochastic Optimal Power Flow Considering N-1 Security Constraints with renewable

This paper proposes a data-driven stochastic optimal power flow model considering the uncertainties of renewable energy sources. The proposed model also focuses on the constraints of reactive voltage, aiming at improving the safety of voltage amplitude and reactive power output at each bus. Using data-driven linearization techniques, we simplified the calculation of system. In addition, Wasserstein ambiguity set was used to describe the uncertainties of renewable energy prediction error distribution, and a robust stochastic optimal power flow model considering N-1 security constraints is established. The simulation results on IEEE-39 system showed the accuracy and effectiveness of the distributionally robust optimization model and the reactive voltage constraint model provided a more stable operation schedule.

Research on the error probability distribution of photovoltaic output prediction based on output fluctuation characteristics and Generalized Gaussian Mixture Model

Photovoltaic power output forecast error exists objectively and inevitably, and it can provide a guarantee for safe and stable operation of the power system through analyzing its characteristics. In this paper, the influence of predicted output fluctuation characteristics (predicted output amplitude and power variation) on prediction error was studied based on the analysis of variance (ANOVA) method. The prediction error conditions were classified into six types based on the clustering of numerical characteristics of predicted output. Then, a Generalized Gaussian Mixture Model (GGMM) was proposed to fit the prediction error distribution of each type of photovoltaic output. The mean absolute error (MAE), coefficient of determination (R2), and root mean square error (RMSE) were used as accuracy evaluation indexes. The example analysis showed that the GGMM can satisfy the asymmetry and kurtosis diversity of the error distribution after division by conditions, and the fitting result is better than that of the normal distribution, improved Laplace distribution and t Location-Scale distribution model.

A stop-timing microchannel plate detector for multi-reflection time-of-flight mass analyzer

A stop-timing microchannel detector with an integrated fast amplifier has been developed and its mechanical and electronic structure described in detail. A typical output amplitude of 1.1 V, rise time of 10 ns, noise amplitude of 2.5 mVrms and timing jitter of 23 ps of the detector have been obtained. The detector has tested with 133Cs1+ ions in the multi-reflection time-of-flight mass analyzer at the Spectrometer for Heavy Atom and Nuclear Structure (SHANS) and a mass resolving power of 19500 has been achieved for a total time-of-flight of 5.85 ms.

A Minimum-Voltage Driving Amplifier with Adaptive Three-Stage Open-Loop Gain and Folded Cascade Class-AB Output Current Control

A driving amplifier capable of operating at a minimum voltage is proposed, aiming to subdue the distortion effect caused by large amplitude driving at the hearing aid loudspeaker. Since the linearity of a cascode amplifier usually degrades with the reduced supply voltage, a three-stage cascade amplifier having a parallel cascade second stage, and a folded cascade Class-AB output current control in place are designed. With such an arrangement, the open loop gain should still be maintained at a sufficiently high level even in the presence of increased output amplitude. Also, the minimum supply voltage required can then be reduced to merely [Formula: see text]. Fabricated on a 0.18[Formula: see text][Formula: see text]m complementary metal oxide semiconductor (CMOS) process, the proposed amplifier achieves [Formula: see text][Formula: see text]dB total harmonic distortion [Formula: see text] with a loudspeaker load of 100[Formula: see text]ohm while operating from a 1.2[Formula: see text]V supply and being subject to a 1[Formula: see text]kHz sinusoidal input.

Area- and Energy-Efficient Sub-GHz Impulse Radio UWB Transmitter With Output Amplitude Enhancement for Biomedical Implants

This brief presents an almost fully digital edge-combining impulse radio ultra-wideband (UWB) transmitter. The proposed output amplitude enhancement technique increases the peak-to-peak amplitude of the UWB output pulse to more than two times that of the traditional UWB transmitter. The pulse width adjustment circuit is designed to ensure the robustness of the UWB circuit against process, supply voltage, and temperature variations. The output power spectrum density of this transmitter is primarily concentrated in the range of 0-960 MHz and can satisfy the mask requirement of the Federal Communication Commission for UWB communication. The proposed UWB transmitter is implemented in a 0.18- μm CMOS process and occupies an area of 97.41 × 68.6 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The measurement results of 20 samples indicate that the average output amplitude is 106.02 mV at a supply voltage of 1 V. At the data transmission rate of 50 Mbps, the measured energy consumptions are 11.18 and 3.97 pJ/bit, respectively, at the supply voltages of 1 and 0.8 V.

Genome-wide correlation analysis to identify amplitude regulators of circadian transcriptome output

Cell-autonomous circadian system, consisting of core clock genes, generates near 24-h rhythms and regulates the downstream rhythmic gene expression. While it has become clear that the percentage of rhythmic genes varies among mouse tissues, it remains unclear how this variation can be generated, particularly when the clock machinery is nearly identical in all tissues. In this study, we sought to characterize circadian transcriptome datasets that are publicly available and identify the critical component(s) involved in creating this variation. We found that the relative amplitude of 13 genes and the average level of 197 genes correlated with the percentage of cycling genes. Of those, the correlation of Rorc in both relative amplitude and the average level was one of the strongest. In addition, the level of Per2AS, a novel non-coding transcript that is expressed at the Period 2 locus, was also linearly correlated, although with a much lesser degree compared to Rorc. Overall, our study provides insight into how the variation in the percentage of clock-controlled genes can be generated in mouse tissues and suggests that Rorc and potentially Per2AS are involved in regulating the amplitude of circadian transcriptome output.

Synthetic protein-binding DNA sponge as a tool to tune gene expression and mitigate protein toxicity

Versatile tools for gene expression regulation are vital for engineering gene networks of increasing scales and complexity with bespoke responses. Here, we investigate and repurpose a ubiquitous, indirect gene regulation mechanism from nature, which uses decoy protein-binding DNA sites, named DNA sponge, to modulate target gene expression in Escherichia coli. We show that synthetic DNA sponges can be designed to reshape the response profiles of gene circuits, lending multifaceted tuning capacities including reducing basal leakage by >20-fold, increasing system output amplitude by >130-fold and dynamic range by >70-fold, and mitigating host growth inhibition by >20%. Further, multi-layer DNA sponges for decoying multiple regulatory proteins provide an additive tuning effect on the responses of layered circuits compared to single-layer sponges. Our work shows synthetic DNA sponges offer a simple yet generalizable route to systematically engineer the performance of synthetic gene circuits, expanding the current toolkit for gene regulation with broad potential applications.

A computer-aided design tool for biomedical OBT sensor tuning in cell-culture assays

Background and objectivesThe biomedical engineering must frequently develop sensor designs by including information from performance of bio-samples (cell cultures or tissues), technical specifications of transducers, and constrains from electronic circuits. A computer program for real-time cell culture monitoring system design is developed; analyzing, modelling and integrating into the program design flow the electrodes, cell culture and test circuit's influences. MethodsThe computer tool, first, generates an equivalent electric circuit model for the cell-electrode bio-systems based on the area covered by cells, which also considers the cell culture dynamics. Second, proposes an Oscillation Based Test (OBT) parameterized circuit, for Electrical Cell-Substrate Sensing (ECIS) measurements of the cell culture system bioimpedance. Third, simulates electrically the full system to define the best system parameter values for the sensor. ResultsReported experimental results are based on commercial gold electrodes and the AA8 cell line. Characteristics of the cell lines, as time-division or cell size, are incorporated into the program design flow, showing that for a given assay, the optimal OBT circuit parameters can be selected with the help of the computer tool. The electrical simulations of the full system demonstrate that the can be correctly predicted the output frequency and amplitude ranges of the voltage response, obtaining accurate results when cell culture approaches to confluence phase. ConclusionIt is proposed a computer program for system design of biosensors applied to monitoring cell culture dynamics. The program allows obtaining confident system information by electrical stimulation. All system components (electrodes, cell culture and test circuits) are properly modelled. The employed procedure can be applied to any other 2D electrode layout or alternative circuit technique for ECIS test. Finally, deep insight information on cell size, number, and time-division can be extracted from the comparison with real cell culture assays in the future.

Inter-Stage Output Voltage Amplitude Improvement Circuit Integrated with Class-B Transmit Voltage Amplifier for Mobile Ultrasound Machines.

Piezoelectric transducers are triggered by the output voltage signal of a transmit voltage amplifier (TVA). In mobile ultrasound instruments, the sensitivity of piezoelectric transducers is a critical parameter under limited power supply from portable batteries. Therefore, the enhancement of the output voltage amplitude of the amplifier under limited power supply could increase the sensitivity of the piezoelectric transducer. Several-stage TVAs are used to increase the voltage amplitude. However, inter-stage design issues between each TVA block may reduce the voltage amplitude and bandwidth because the electronic components of the amplifier are nonlinearly operated at the desired frequency ranges. To compensate for this effect, we propose a novel inter-stage output voltage amplitude improvement (OVAI) circuit integrated with a class-B TVA circuit. We performed fundamental A-mode pulse-echo tests using a 15-MHz immersion-type piezoelectric transducer to verify the design. The echo amplitude and bandwidth when using an inter-stage OVAI circuit integrated with a class-B TVA circuit (696 mVPP and 29.91%, respectively) were higher than those obtained when using only the class-B TVA circuit (576 mVPP and 24.21%, respectively). Therefore, the proposed OVAI circuit could be beneficial for increasing the output amplitude of the class-B TVA circuit for mobile ultrasound machines.

Wideband 4 × 4 Butler Matrix in the Printed Ridge Gap Waveguide Technology for Millimeter-Wave Applications

A wideband printed ridge gap waveguide $4\times 4$ Butler matrix at 30 GHz is presented. The printed ridge gap technology is used as it has very low losses and supports the propagation of quasi-TEM mode. Each component of the Butler matrix has been designed and analyzed where a superior performance is achieved in terms of bandwidth and size. The designed components are combined to form the Butler matrix. The Butler matrix has a wideband performance where the return loss and isolation levels are higher than 10 dB in the frequency range from 26.9 to 33.3 GHz, the output amplitude imbalance is ±1.6 dB, and the phase error is ±10°. The measured radiation patterns are in a good agreement with the simulated ones, beam directions are at ±13° and ±36° at the center frequency. The gain is ranging from 10.2 to 11.35 dBi for excitation from port 1 and ranging from 8.4 to 10.2 dBi for excitation from port 2.

The impact of memory effect on resonance behavior in a fractional oscillator with small time delay

We study stochastic resonance (SR) phenomenon in the fractional oscillator with time delay and damping fluctuation, analyze the impact of time delay and fractional damping as two memory ingredients on SR, and put forward firstly the concept of the robustness of GSR. By moment method, we obtain the analytical expression of the output amplitude gain and find that fluctuations in the output amplitude gain are non-monotonic. Using numerical simulations we verify the accuracy of the analytical results. We find (i) that the length of time delay and system order are parameters related to memory; (ii) that the output amplitude gain could attain a maximum by increasing driving frequency close to system frequency, and small time delay and system order contribute to enhance the resonance intensity; (iii) that the evolution of the output amplitude gain versus the noise intensity exhibits one-peak resonance, and small time delay can enhance the resonance intensity and the robustness of SR regarding to driving frequency and system frequency; (iv) that the evolution of the output amplitude gain versus the noise correlation rate presents one-peak resonance in the presence of small time delay, critical time delay is bigger with the increasing system order when noise intensity is fixed and critical time delay is smaller with the increasing noise intensity when system order is fixed.

A Compact Wideband Millimeter-Wave Quadrature Hybrid Coupler Using Artificial Transmission Lines on a Glass Substrate

In this letter, a compact branch-line-based quadrature hybrid coupler using a line miniaturization technique for a 28-GHz application is presented. Coplanar waveguide-based artificial transmission lines are used in the miniaturization, and T-equivalent circuit models are exploited to elaborate on the optimization method. A multistage T-model is utilized to eliminate the need for lumped elements, improve bandwidth performance, and simplify the fabrication process. To validate the proposed approach, the designed quadrature hybrid coupler was fabricated on a glass substrate. The measured insertion loss and phase difference at 28 GHz were 3.86 dB, 3.94 dB, and 90.4°, respectively. The output amplitude imbalance was within a 1-dB range from 25.3 to 31.0 GHz, and the total device area, excluding the measurement pad, was $1.15\times0.98$ mm2.

Carrier wave optimization for multi-level photovoltaic system to improvement of power quality in industrial environments based on Salp swarm algorithm

The use of multi-level inverters is increasing in different structures, high power and medium power applications due to advantages such as low switching losses, harmonic distortion and electromagnetic interference at the output which could be used in microgrid systems. A microgrid can be defined as groups of renewable energy sources such as photovoltaic and wind turbine i.e. The switching technique for inverter control plays a significant role in reducing or eliminating the harmonics of inverter output voltage and reducing the switching losses. To minimize the distortion of the output voltage of the cascaded H bridge multi-level inverter due to low-order harmonics, an optimization method used for frequency selection, i.e. the carrier wave amplitude in the SPWM strategy within this study. The proposed method is called OSPWM, which employs a new optimization method based on the Salp swarm algorithm. The proposed method applied to a cascade H bridge five-level inverter. The simulation results show the reduction of the low-frequency harmonics amplitude and THD output voltage by optimizing the OSPWM carrier wave parameters with the optimization algorithm. The proposed method also compared with the classical SPWM method.

Design and Finite Element Analysis of Axial Low-frequency Vibration Tool-holder

Vibration-assisted drilling can significantly reduce the drilling force and cutting heat during deep hole machining, improve tools life and hole machining quality. As a branch of vibration drilling technology, axial low-frequency vibration-assisted drilling has a broad application prospect in the field of drilling because of its simple structure and easy implementation. A mechanical axial low-frequency vibrating tool-holder (ALVT) is designed, and the overall structure layout and working principle of the vibrating tool-holder are analyzed. The rotary motion of the machine tool spindle is used as the power input to drive the sinusoidal surface to rotate to achieve the amplitude output. The vibrating tool-holder model is simplified, and the ABAQUS finite element software is used to simulate the titanium alloy material for ordinary drilling and axial low-frequency vibration drilling (ALVD), and the axial force and cutting temperature changes are compared and analyzed. The results show that ALVD of titanium alloy can reduce the average axial force by about 47% and the cutting temperature by about 11%, which can significantly improve the drilling conditions and the quality of hole machining.

Stochastic resonance in two coupled fractional oscillators with potential and coupling parameters subjected to quadratic asymmetric dichotomous noise

Exact analytical expressions for the average output amplitude gains in the very long-time limit for two coupled oscillators governed by fractional-order intrinsic and external damping, under the influence of a multiplicative quadratic asymmetric dichotomous noise affecting the two potential parameters and the coupling factors, and subjected to a noise-free or noise-modulated external periodic force with same frequency, have been derived. The trustworthiness of the analytical expressions has been checked by comparing the numerical results obtained using these for some typical cases with corresponding findings based on numerical simulations. The numerical simulations have also been used to investigate the time-evolution of a representative system in the transient state by studying the probability density and displacements of the two oscillators at different times and for different values of noise intensity. Analytical expressions have been used to obtain plots for gains versus noise intensity to study the effect of (i) variation in mass parameter of one oscillator keeping that of other the same, and (ii) change in the relative values of the two coupling coefficients. Furthermore, the special case where both the potential parameters are taken to be zero, which corresponds to rectilinear motion of the two particles in the absence of fluctuations, has been examined under the influence of the second-order noise and stochastic resonance has been found to occur at lower frequencies of the applied force. This highlights the importance of nonlinear term in the noise, which makes the rectilinear motion to be oscillatory. Also, the key role played by the coupling in this has been brought out.

Why the natural frequency and the damping coefficient do not evaluate the dynamic response of clinically used pressure monitoring circuits correctly.

The dynamic response of pressure monitoring circuits must be evaluated to obtain true invasive blood pressure values. Since Gardner's recommendations in 1981, the natural frequency and the damping coefficient have become standard parameters for anesthesiologists. In 2006, we published a new dynamic response evaluation method (step response analysis) that can plot frequency spectrum curves instantly in clinical situations. We also described the possibility of the defect of the standard parameters. However, the natural frequency and the damping coefficient are considered the gold standard and are even included in a major anesthesiology textbook. Therefore, we attempted to clarify the issues of these parameters with easy-to-understand pressure waves and basic numerical formulae. A blood pressure wave calibrator, a single two-channel pressure amplifier, and personal computer were used to analyze blood pressure monitoring circuits. All data collection and analytical processes were performed using our step response analysis program. We compared two different circuits with almost the same natural frequency and damping coefficients. However, their amplitude spectrum curves and input/output pressure values were significantly different. The natural frequency and the damping coefficient are inadequate for the dynamic response evaluation. These parameters are primarily obtained from the phase spectrum curve and not from the amplitude spectrum curve. We strongly recommend an evaluation using the amplitude spectrum curve with our step response analysis method. It is crucial to maintain an amplitude gain of 1 (input amplitude = output amplitude) in the pressure wave frequency range of 0-20Hz.

Parametric study of gamma-type free piston stirling engine using nonlinear thermodynamic-dynamic coupled model

A reliable thermodynamic-dynamic coupled model for a gamma-type FPSE possessing nonlinear load damping coefficient has been proposed in this study. Simultaneously, the experimental results are compared with the model and a satisfactory agreement is obtained. The output power is predicted with less than 5% error under different hot-end temperatures. Then the amplitude of displacer and piston with time at different pistons’ positions are obtained, and the effects of load damping and nonlinear coefficients on the amplitude values of two pistons and output power are presented. Finally, a simulation study is carried out to investigate the sensitivity of thermodynamic-dynamic parameters to the amplitude of two pistons, operating frequency and output power, and the fitting formulas for evaluating the performance of FPSE are presented. It is found that the initial positions of two pistons have little effect on pistons’ amplitude in the FPSE nonlinear system. High charge pressure, hot-end temperature, and spring stiffness of the displacer can increase the output power and amplitude of the pistons while other parameters have a negative effect on them. The fitting equations have high accuracy. This work provides a reliable model and theoretical guidance for improving the FPSE’s performance.

Optimization design of a new type of high-frequency piezoelectric ultrasonic transducer with the compliant hinge-based mounting clamp

Piezoceramic-based ultrasonic transducers are widely used in the fabrication and packaging of the microelectronic device and their performance largely depends on the ultrasonic energy delivery efficiency (UEDE) which can be reflected by the tip vibration amplitude output (TVAO) of the transducer indirectly. Recently, it was reported that a new type of flexure hinge-based mounting clamp could enhance the TVAO of the transducer significantly. To get the best effect, this research aimed at developing an optimization method for this newly proposed mounting clamp. For the purpose, a series of researches were performed against a self-developed transducer equipped with a pair of circular notched hinge-based mounting clamps. Firstly, the influential rules of several key geometric parameters of the flexure hinge on the TVAO of the ultrasonic transducer were explored. Then, an optimization objective function together with a group of constraints was constructed. Next, the Particle Swarm Optimization (PSO) algorithm was used to optimize the geometric parameters of the circular hinge-based mounting clamp. Finally, the performance of the optimized mounting clamp was tested based on a measurement and evaluation system. The results show the optimized mounting clamp can enhance the TVAO of the transducer greatly, presenting a good improvement effect of the UEDE, and manifesting the feasibility and effectiveness of the developed method.

Static Gain Estimation for Automatic Generation Control Systems From Historical Ramp Responses

This brief proposes an approach to estimate static gains of dynamic models for automatic generation control systems in coal-fired power generation units. The main idea is to infer static gains of dynamic models from amplitude changes of model inputs and outputs in finite-time ramp responses. First, input and output time sequences are approximated by a few straight lines as piecewise linear representations. Second, finite-time ramp responses are detected as the data segments where inputs and outputs simultaneously move along straight lines with significant amplitude changes. Third, estimated static gains are obtained by solving linear equations of significant amplitude changes in the ramp responses. One technical challenge of selecting the thresholds of significant amplitude changes is resolved by exploiting a relationship among the amplitude change, noise variance, and signal-to-noise ratio. Comparing with a standard system identification approach, the obtained results from the proposed approach can be validated in a convincing manner: ramp responses being found from historical data samples can be confirmed by checking whether data segments of inputs and outputs are actually in straight lines; estimated static gains can be verified by comparing output amplitude changes in the ramp responses with their estimated values. Numerical and industrial examples are provided to support the proposed approach.

Simulation of measuring transducers based on interconnected piezoresonators

The article presents the results of simulation of the operating modes of measuring transducers based on interconnected piezoresonators. The article discusses modulation options as a function of the measured effects of the parameters of equivalent electrical equivalent circuits of piezoresonators and coupling elements between them. The article describes the features of using coupled oscillations in systems with two degrees of freedom for constructing differential-type sensors with a frequency and amplitude output. The article gave examples of the practical implementation of measuring devices based on coupled oscillations of piezoresonators.