Input Phase Research Articles

Individual Particle Characteristics, Optical Properties and Evolution of an Extreme Long‐Range Transported Biomass Burning Event in the European Arctic (Ny‐Ålesund, Svalbard Islands)

AbstractThis paper reports an exceptional biomass burning (BB) advection event from Alaska registered at Ny‐Ålesund from 10 to 17 July 2015 with particular interest on the influence of the airborne particle characteristics on the optical properties of the aerosol during the event. To this purpose we considered two DEKATI 12‐stage aerosol samples spanning the entire advection and analyzed them by scanning electron microscopy techniques. Aerosol chemical data and microphysical properties were also evaluated in order to correlate any change of individual particle characteristics with the bulk properties of the aerosol. The results of individual particle analysis depict a complex event characterized by a first phase (P1) of massive input of BB carbonaceous particles (i.e., tar balls, popcorn refractory particles, and organic particles), and by a second phase (P2) dominated by inorganic salts. The peculiar feature of this BB event is the exceptionally large grain size of the subspherical organic particles at the beginning of the event with respect to the background. At these conditions a significant increase of the scattering efficiency may occur even for a small increase of the size parameter. Results of the simulation of the complex refractive indices (n‐ik) confirm this evaluation. Aerosol evolution during the event resulted from the combination of three distinct occurrences: (a) progressive rotation of air mass circulation toward non‐BB source areas, (b) development of a thick fog layer in the planetary boundary layer, and (c) sea salt spray direct advection of local/regional provenance.

Transferring and Optimizing a Laptop-based Learning Environment for the Use on iPads

With the growing presence of laptops, smartphones and tablets, daily life as well as professional needs are changing [1]. However, this means that mobile devices are playing an increasingly important role in schools and classrooms [2,3]. In particular, tablets are seen as a highly promising possibility to implement digital media in schools [4]. In this context, we would like to take a closer look at the use of tablets in initial chemistry classes. Therefore, we transferred a digital learning software, that had been developed for laptops, to iPads in order to optimize the learning environment through the possibilities offered by this latest innovation. This further development especially aims at the integration of experiments and a higher universal accessibility for learners in heterogeneous or inclusive learning groups. The aim of this project is to investigate the effect of the use of tablets in the following two teaching phases: During the input phase, the students work on the iPad-based learning environment. In the internalization phase, working with tablet-based tasks is compared with creating student explanatory videos regarding their impact on knowledge growth and attractiveness. In this paper, we focus the transfer of the laptop-based learning environment to iPads.

Evaluation of Authentic Assessment Implementation in SDN 101775 Sampali, Deli Serdang Regency, Academic Year 2019/2020

This research is an evaluation research with a quantitative descriptive approach. The evaluation model used is the Stake Countenance Model. The subjects of this study were all teachers in SDN 101775 Sampali, Deli Serdang Regency with a total of 12 teachers. Data collection techniques using observation, questionnaires, documentation and interviews. In analyzing data using descriptive methods. From the results of research conducted on the evaluation of the implementation of authentic assessment in SDN 101775 Sampali Deli Serdang Regency with a stake countenance evaluation model that is 90.39%. This is evidenced from the three stages of stakeholder evaluation in the implementation of authentic assessment which consists of an input phase (antecendents phase) which is evaluated consisting of analysis of learning documents, attitude assessment documents, knowledge assessment documents and skills assessment very well complete with a percentage of 89.46% . In the transaction phase that was evaluated, namely how the authentic assessment carried out by the teachers at SDN 101775 Sampali was carried out very well with a percentage of 90.71%. In the evaluated outcome phase which is the reporting of student learning outcomes and teacher understanding of the implementation of authentic assessment in schools has been going very well with a percentage of 91%. The next suggestion for the implementation of authentic assessment is continuously monitored so that the teacher's understanding of the implementation of authentic assessment can be carried out properly.

Fundament of input power distribution and phase shifter functions of a step displacer type two-stage pulse tube refrigerator

Abstract Compared with double inlet type two-stage pulse tube refrigerator, step displacer type has higher efficiency. The step displacer has two functions, input power distribution function and phase shifting function, which are fundamental issues of this type refrigerator. The two functions are discussed by an ideal model, and are investigated by a numerical simulation. Theoretically, the exergy flow ratio to the first stage over the second stage depends on the refrigeration temperature ratio and step ratio, the dead volume at the hot end of the pulse tube can be an additional parameter for adjusting the phase angle difference at the cold end of the regenerator.

Theoretical and Experimental Analysis of a 4 × 4 Reconfigurable MZI-Based Linear Optical Processor

A 4 × 4 reconfigurable Mach–Zehnder interferometer (MZI)-based linear optical processor is investigated through its theoretical analyses and characterized experimentally. The linear transformation matrix of the structure is theoretically determined using its building block, which is a 2 × 2 reconfigurable MZI. To program the device, the linear transformation matrix of a given application is decomposed into that of the constituent MZIs of the structure. Thus, the required phase shifts for implementing the transformation matrix of the application by means of the optical processor are determined theoretically. Due to random phase offsets in the MZIs resulting from fabrication process variations, they are initially configured through an experimental protocol. The presented calibration scheme allows to straightforwardly characterize the MZIs to mitigate the possible input phase errors and determine the bar and cross states of each MZI for tuning it at the required sate before programming the device. After the configuration process, the device can be programmed to construct the linear transformation matrix of the application. In this regard, using the required bias voltages, the phase shifts obtained from the decomposition process are applied to the phase shifters of the MZIs in the device.

An End-to-End Deep Learning Framework for Recognizing Human-to-Human Interactions Using Wi-Fi Signals

Channel state information (CSI)-based human activity recognition plays an essential role in various application domains, such as security, healthcare, and Internet of Things. Most existing CSI-based activity recognition approaches rely on manually designed features that are classified using traditional classification methods. Furthermore, the use of deep learning methods for CSI-based activity recognition is still at its infancy with most of the existing approaches focus on recognizing single-human activities. The current study explores the feasibility of utilizing deep learning methods to recognize human-to-human interactions (HHIs) using CSI signals. Particularly, we introduce an end-to-end deep learning framework that comprises three phases, which are the input, feature extraction, and recognition phases. The input phase converts the raw CSI signals into CSI images that comprise time, frequency, and spatial information. In the feature extraction phase, a novel convolutional neural network (CNN) is designed to automatically extract deep features from the CSI images. Finally, the extracted features are fed to the recognition phase to identify the class of the HHI associated with each CSI image. The performance of our proposed framework is assessed using a publicly available CSI dataset that was acquired from 40 different pairs of subjects while performing 13 HHIs. Our proposed framework achieved an average recognition accuracy of 86.3% across all HHIs. Moreover, the experiments indicate that our proposed framework enabled significant improvements over the results achieved using three state-of-the-art pre-trained CNNs as well as the results obtained using four different conventional classifiers that employs traditional handcrafted features.

Study on high precision single-pole magnetic encoder based on error analysis and compensation method

This paper introduces the basic principle of single-pole magnetic encoder and its application in industrial field, and analyses three main sources of errors of single-pole magnetic encoder, including unequal amplitude of signal, non-orthogonal phase of input signal, and high order harmonic in input signal. According to the principle of the decoding algorithm of the magnetic encoder, the paper pushed out mathematical expression of each kind of error, and developed the corresponding compensation measures according to these expressions. Finally, we using the STM3232F103 microprocessor as the carrying platform of the algorithm and the 16-bit precision servo motor system as a reference, verified the validity of the error compensation algorithm.

Enhancing gain with multiple beams for four element phased array microstrip antenna using Rogers substrate material for 5G applications

5G wireless systems are improved networks to be deployed recently. The newly specified frequency bands, in which 5G operates, comes in the millimetre wave bands (26, 28, 38, and 60 GHz). In this paper, a four element microstrip antenna having dimensions 27.7 X 27.7 X 1.27 mm3 is designed at a frequency of about 27–28 GHz that shows improved performance over a single element antenna. The antenna works, on a minimum attenuation level of around −38 dB and a gain of around 13.7 dB, with a HPBW of 23.4 degrees at a frequency of 27.74 GHz. The antenna is having 8 ports where each element is fed by two ports and multiple beam patterns can be obtained by changing the relative phase of inputs given at different ports. The designed antenna can be directed in single direction (Theta = 0 degree when phi = 0 degree), two different directions (Theta = ±22 degree when phi = 0 degree), three different directions (phi = 105, −80 and 180 degrees for theta = 90 degrees) and four different directions (phi = 0, −90, 90 and 180 degrees for theta = 90 degrees) at the same time with varying gain and half power beam width. The maximum gain is obtained with a single beam that keeps on decreasing with increasing number of beams. The simulation for antenna is done on CST Microwave Studio using the substrate material Rogers RT5880LZ having dielectric constant 1.96 and a thickness of 1.27 mm.

Coupled Inductor Based Regenerative Cascaded Multicell Converter for Drives With Multilevel Voltage Operation at Both Input and Output Sides

Cascaded multicell converter (CMC) is proved to be an effective solution for medium voltage drives. Three-phase diode bridge rectifiers are normally used in this converter, which do not have regeneration capability. Pulsewidth-modulated (PWM) rectifier-based power cells enable the drives with regeneration capability. However, due to their two-level voltage operation at the input side, an inductor is required for each cell to filter out the switching frequency components from the input current. In this paper, a new configuration with single-phase PWM rectifier-based power cell is proposed to achieve multilevel voltage operation at both the input and output sides of the converter. Therefore, the devices at the rectifier side are also operated at reduced switching frequency without using any filter inductor for each cell. In the proposed converter, simple modular transformers are used instead of a single large and complex transformer that is used in the conventional CMC. Further, input phase currents of the converter are controlled in the synchronously rotating d–q frame, which requires only two current sensors at the input side instead of individual current sensors for each cell. Experimental validation of the proposed converter configuration is carried out on a 4.5-kVA prototype, and the results are presented.

Simplified Space-Vector Modulation Strategy for Indirect Matrix Converter With Common-Mode Voltage and Harmonic Distortion Reduction

This paper presents a simple space vector modulation (SVM) strategy for a three-phase indirect matrix converter (IMC) to reduce common-mode voltage (CMV) and output harmonic distortion. To suppress the CMV peak value to 57.7% of the input phase voltage, three active voltage vectors are used to generate the desired output voltage with arbitrary amplitude and frequency. However, the output waveform quality of the IMC deteriorates due to the absence of zero voltage vectors. To overcome this problem, this paper proposes to redesign control of the rectifier stage by utilizing three active current vectors instead of two, as is common. Consequently, a constant average DC-link voltage is achieved, which can improve the output performance in terms of output voltage and current harmonic distortion. Compared to the existing strategies, the proposed strategy can reduce the CMV and maintain output harmonic distortion without increasing the computation burden. Implementation of the proposed strategy is also straightforward and simple. Simulated and experimental results are provided to verify the effectiveness of the proposed strategy.

A 951-fsrms Period Jitter 3.2% Modulation Range in-Band Modulation Spread-Spectrum Clock Generator

A spread-spectrum clock generator is proposed based on an in-band phase modulation. In a charge-pump phase-locked loop configuration, the input phase modulation signal is applied to the proposed charge-based discrete-time loop filter. The phase difference between the input phase modulation signal and the output clock feedback phase is sampled and applied to the control voltage of an oscillator. The loop gain of the clock generator pushes the output clock phase to accurately trace the input phase modulation signal. This article achieves 3.2% spread-spectrum modulation range and 26.51-dB spread-spectrum attenuation at 352-MHz output frequency using a 2-MHz reference frequency. The in-band modulation improves a design sensitivity, and a 298-ppm modulation range error is measured with over 140% $K_{\mathrm{ VCO}}$ perturbations. This spread-spectrum clock generator is implemented in a 0.18- $\mu \text{m}$ CMOS, and achieves 951-fsrms period jitter while consuming 9.98 mW from a 1.8-V power supply.

Sparsity-based phase spectrum compensation for single-channel speech source separation

This paper proposes a sparsity-based phase spectrum compensation (SPSC) function to improve the quality of reconstructed signals by using magnitude-based single-channel speech source separation. While conventional approaches to the reconstruction of separated sources use the input phase spectrum, the proposed SPSC function modifies each source's phase spectrum using the estimated magnitude spectra of multiple sources and their spectro-temporal sparsity. In particular, the spectro-temporal sparsity is estimated from the signal-to-interference ratio between the magnitude spectrum of a source to be separated and those of the other sources, including the background noise. The proposed SPSC function is first embedded into the reconstruction stage of magnitude-based speech source separation methods that employ deep recurrent neural network (DRNN) and sparse nonnegative matrix factorization (SNMF), respectively. Then, speech denoising is performed under four different noise conditions with signal-to-noise ratios (SNRs) in the range of 0–15 dB. Both objective and subjective tests show that both DRNN and SNMF-based speech separation methods employing the proposed SPSC function substantially outperform those employing the conventional PSC function for the speech denoising task. Moreover, the DRNN combined with the proposed SPSC function offers higher average perceptual evaluation of speech quality (PESQ) scores for speech denoising than SEGAN, which is based on a very large end-to-end neural networks model. Next, the proposed SPSC method is also applied on the reconstruction stage of a deep clustering-based speech separation method to examine its contribution on a multi-talker speech separation task, where spoken utterances of males and females are mixed at −3, 0, and 3 dB SNR. It is shown from the experiment that the proposed SPSC function further improves SDR and PESQ scores of the magnitude spectra processed by the deep clustering-based single-channel speech separation method.

Direction reconfigurable nonreciprocal acousto-optic modulator on chip

Nonreciprocal components are essential in photonic systems for protecting light sources and for signal routing functions. Acousto-optic methods to produce nonreciprocal devices offer a foundry-compatible alternative to magneto-optic solutions and are especially important for photonic integration. In this paper, we experimentally demonstrate a dynamically reconfigurable nonreciprocal acousto-optic modulator at the telecom wavelength with a peak contrast of 8 dB and a 3 dB bandwidth of 1.1 GHz. The modulator can be arranged in a multitude of reciprocal and nonreciprocal configurations by means of an external RF input. The dynamic reconfigurability of the device is enabled by a new cross-finger interdigitated piezoelectric transducer that can change the directionality of the reciprocity-breaking acoustic excitation based on the phase of the RF input. The methodology we demonstrate here may enable new avenues for direction dependent signal processing and optical isolation.

Timescale Ensemble Performance Enhancement through use of Artificial Neural Network

AbstractA timescale is the estimate of phase and frequency of the “perfect” clock derived from the phase and frequency of the clocks which participate in the ensemble. An ensemble of clocks is the first step towards the realization of a timescale. In the past, several methodologies have been developed to solve the timescale problem such as KAS‐2, Multi‐scale Ensemble Timescale (METS), ALGOS (BIPM), AT1 (NIST) and algorithm for UTC (CRL). An adaptive ensemble algorithm based on Artificial Neural Network (ANN) has been developed which shows improvements in terms of betterment of frequency stability of the ensemble. The Neural Network in the ensemble algorithm learns differently for different sample spaces of the input phase data that is provided. The weights of the participating clocks are derived from their respective Allan deviations. The weights formulated for the ensemble undergo a regressive iteration to obtain the training data set for parameterization of weights. A single‐layer perceptron feedback Neural Network that is proposed in this paper, dynamically adapts the weights assigned to the participating clocks based on the paper clock performance.This paper dwells on the comparison of performances between the ANN‐based algorithms with that of two other algorithms, namely Reduced Kalman filter based algorithm and METS. Results of ANN‐based algorithm for different clock combinations are also presented. The behavior of this algorithm in the event of measurement data outage has also been presented in the paper.

A Fully Digital Semirotational Frequency Detection Algorithm for Bang–Bang CDRs

This brief presents a new frequency acquisition method using a semirotational frequency detection (SRFD) algorithm for referenceless clock and data recovery (CDR) in a serial-link receiver. The proposed SRFD algorithm classifies the bang–bang phase detector (BBPD) outputs to estimate the current phase state and detects the frequency mismatch between the input data and the sampling clock. The voltage-controlled oscillator (VCO)-track path in a digital loop filter (DLF) enables online calibration of a drifted frequency of the VCO caused by temperature or voltage variation after a frequency acquisition. The proposed algorithm can be implemented as a digitally synthesized circuit, lowering design efforts for referenceless CDRs. A 10-Gb/s transceiver IC with the proposed algorithm, fabricated in a 65-nm CMOS process, demonstrates successful recovery of the input phase without any reference clock.

QSMGAN: Improved Quantitative Susceptibility Mapping using 3D Generative Adversarial Networks with increased receptive field

Quantitative susceptibility mapping (QSM) is a powerful MRI technique that has shown great potential in quantifying tissue susceptibility in numerous neurological disorders. However, the intrinsic ill-posed dipole inversion problem greatly affects the accuracy of the susceptibility map. We propose QSMGAN: a 3D deep convolutional neural network approach based on a 3D U-Net architecture with increased receptive field of the input phase compared to the output and further refined the network using the WGAN with gradient penalty training strategy. Our method generates accurate QSM maps from single orientation phase maps efficiently and performs significantly better than traditional non-learning-based dipole inversion algorithms. The generalization capability was verified by applying the algorithm to an unseen pathology--brain tumor patients with radiation-induced cerebral microbleeds.

Evaluation of Authentic Assessment Implementation in Public Elementary School 101775 Sampali, Deli Serdang Regency Academic Year 2019/2020

This research is a type of evaluation research with a quantitative descriptive approach. The evaluation model used is the Stake Countenance Model. The subjects of this study were all teachers in Public Elementary School 101775 Sampali, Deli Serdang Regency with a total of 12 teachers. Data collection techniques using observation, questionnaires, documentation and interviews. In analyzing data using descriptive methods. From the results of research conducted on the evaluation of the implementation of authentic assessment in Public Elementary School 101775 Sampali Deli Serdang Regency with a stake count maintenance evaluation model of 90.39%. This is evidenced from the three stages of stakeholder evaluation in the implementation of authentic assessment which consists of an input phase (Antecedents phase) which is evaluated consisting of analysis of learning documents, attitude assessment documents, knowledge assessment documents and skills assessment very well complete with a percentage of 89.46% . In the transaction phase that was evaluated, namely how the authentic assessment carried out by the teachers at Public Elementary School 101775 Sampali was carried out very well with a percentage of 90.71%. In the evaluated outcome phase which is the reporting of student learning outcomes and teacher understanding of the implementation of authentic assessment in schools has been going very well with a percentage of 91%. The next suggestion for the implementation of authentic assessment is continuously monitored so that the teacher's understanding of the implementation of authentic assessment can be carried out properly.

Interference of Spin Waves in Arrays of Microwaveguides Based on Yttrium-Iron Garnet Films

Effects of propagation and interference of spin waves in an eight-port magnonic structure in the form of a 2 × 2 array of microwaveguides based on yttrium-iron garnet films with microantennas placed at the waveguide ends are studied experimentally and numerically. It is shown that conditions for a constructive and destructive interference of spin waves, which is necessary for creating spin-wave logic devices, can be implemented at output transducers by changing the phase of input signals.

Fully nonlinear investigation of focused wave slamming on a freely rotating flap

This paper concerns the focused wave slamming induced by a freely rotating flap using domain-decomposition higher-order boundary element method (HOBEM) with fully nonlinear conditions through which the process of jet detaching from body is successfully captured. The stable results of splash jet are obtained through linearly-varying-potential hypothesis. The time derivative of velocity potential on the body surface is calculated through the auxiliary function method, and the strong mutual dependence between the flap and the fluid flow is further decoupled accordingly. The non-uniform mesh scheme is adopted in the computational domain to guarantee both efficiency and accuracy, i.e., using fine meshes in the slamming region with strong nonlinearity. The abilities of present model to generate the focused wave and simulate wave slamming on a rotating flap, are respectively, verified. Relatively comprehensive parametric studies are performed, and the results based on flap's motion states, free surface profiles and pressure distributions point out the effects of frequency bandwidth, focused position, input wave amplitude, water depth and phase angle on the slamming specifically. It has been found the slamming occurs before wave groups focus completely and focused trough further enlarges the slamming pressure compared with focused crest.

Control Strategy for Single-Phase Open-Circuit Operation of a Modular Solid-State Transformer

The solid-state transformer (SST) has the ability to operate with only two input phases, which can be called single-phase open-circuit (SPO) operation. With this ability, the SST can maintain operation under permanent single-phase-to-ground faults, where the fault phase must be isolated, providing a better power supply sustainability than that of the conventional low-frequency transformer. In the absence of research on the SPO operation of an SST, this paper presents a study of it. The influence of SPO operation on the grid and the SST itself is analyzed. Under the SPO state, the SST will inject the negative-sequence current to the grid; meanwhile, the maximum load power will decline; thus, the optimized power factor under the SPO state is unity. The maximum power of △-SST is higher than that of the Y-SST under the SPO state owing to the △ connection. A control strategy for the SST medium-voltage cascaded H-bridge stage is proposed. SPO current control can be achieved by controlling the positive-sequence current. A proper negative-sequence voltage can be injected to synchronize the cluster voltages to obtain a lower current total harmonic distortion and smaller dc voltage ripple. In the △-SST, a proper zero-sequence current can be injected to fully use the power rating of the double-cluster branch.