bluuebunny/crossref_metadata_2025 huggingface dataset:
AIVMAF: Automatic Image Quality Estimation Based on Improved VMAF and YOLOv4
Authors: Du Juan
Published: June 2022

The current most widely used way of image quality estimation relies heavily on the subjective assessment, while majority of past objective estimation methods are not satisfactory on accuracy. To solve them and realize unsupervised image quality estimation with high precision, this paper creates a linear way with “Proportional Partition” controlled by horizontal and vertical rates of extracted pixel to get best representations of the image with patching, balance the uneven distribution of image quality in each source image, and offer dynamic compatibility to images with high resolution. Besides, it estimates the image quality automatically with a model trained by current best artificial intelligence (AI) algorithm for target detection YOLOv4 with 1000 images random selected from ImageNet2013 database. The proposal also uses the spirit of joint indices from the current widely used method named Video Multimethod Assessment Fusion (VMAF). But we replace its Visual Information Fidelity (VIF) with Visual Saliency-induced Index (VSI) and add VSI to our target function because of VIF’s dependence on subjective assessment, and also for VSI’s better performance surpassing most recent IQA estimators as TOP3 best model in recent world. Besides, contrast masking is also included by objective function for the KL-divergence to simulate the human visual perception better. A creative “Batch Learning” way is found to address patches for less calculation and faster speed. All source images are pretreated with colour space transformation and normalization to improve descriptiveness of images and reduce the redundant points, and a threshold is devised to formulate suppression mechanisms. The proposed solution is tested to be a good image quality assessor in many aspects such as correctness, consistency, linearity, monotonicity and speed, and performs well on even HD images.
Athlete Exercise Intensity Recognition Method based on ECG and Convolutional Neural Network
Authors: Zhu Yingbo , Wang Baiyang , Zhang Fuchun , Zhu Haiyan
Published: June 2022

Unreasonable exercise will cause damage to the body. In physical education, coaches only use physiological indicators such as heart rate and breathing to judge the physiological state of athletes, which is highly subjective and is not conducive to accurately judging the physiological state of athletes. In order to effectively monitor athletes in exercises, a method for identifying athletes' exercise intensity based on ECG and convolutional neural network was proposed. In this method, the more informative ECG signal is used as the physiological indicator of the athlete's exercise intensity, combined with the convolutional neural network for feature extraction, and finally the training model is used to monitor and evaluate the athlete's exercise intensity. The method implements automatic feature extraction and recognition of athletes' ECG signals. The simulation results of the dataset show that the method can effectively judge the exercise intensity, and the accuracy can reach 98.6%. At the same time, the algorithm has a small amount of calculation and a fast convergence speed, in the daily training of athletes has a good auxiliary role.
Internet of Things Detection and Location Based on Remote Communication Fault of Power Consumption Acquisition Module
Authors: Zhu Yiqun , Zheng Jijun , Li Zhen , Liu Xiaolei
Published: June 2022

The access of distributed generation makes the single-source radial distribution network become a complex multi-source network. The power flow, network loss, voltage, and so on are also changing. At the same time, it aggravates the complexity of remote communication fault location of remote communication fault power acquisition module based on the Internet of Things. In this paper, a new switching function and evaluation function are used to adapt to the situation of distributed generation access. Considering that the fault section location is a discontinuous problem, the binary particle swarm algorithm is used to make full use of its fast convergence and combine with the operation of diversity preservation to realize the fault section location. The experimental results show that the hybrid algorithm in this paper has a good effect on fault recovery, and has certain advantages and theoretical research value in optimization ability.
An Adaptive Threshold Detection Circuit for Action Potential
Authors: Zhuang Zhilin , Li Xiaolong , Wang Jie , Dai Minghui , Ma Shumiao
Published: June 2022

In order to find the action potential hidden in the neural signal, this study proposes a method of detecting the action potential through adaptive threshold, and designs an adaptive threshold detection circuit which can be used for the action potential. Different from the past, the circuit controls the gain by the current of the input signal itself, so as to generate an appropriate adaptive comparison threshold. This circuit not only retains the advantages of the traditional threshold detection method, but also can quickly respond to the input signal, generate an appropriate comparison threshold and detect the action potential without external supervision. The spectre simulation shows that when the power supply voltage is 1.8V, the adaptive threshold generation circuit can accurately detect the action potential without missing or wrong detection.
Application of BP neural network in on-board charger fault diagnosis
Authors: Duan Xiuzhen , Li Xiaopeng , Liu Yaning
Published: June 2022

With the accelerated growth of the number of electric vehicles, the frequent occurrence of electric vehicle charging safety accidents has brought some safety hazards to people. The fault diagnosis of on-board charger circuit has gradually become the focus of attention of scholars. This paper uses simulation software to conduct modeling simulation analysis, failure mode analysis and data acquisition for the on-board charger of electric vehicles, and establishes a fault diagnosis model based on BP neural network, which is applied to the fault diagnosis of on-board charger circuits. The optimal fault diagnosis model is obtained by continuously adjusting the number of neurons in the hidden layer of the BP neural network, and the open-circuit faults of diodes and MOSFETs are mainly analyzed experimentally. The simulation results show that the expected effect has been achieved in the fault diagnosis of the on-board charger circuit, and the established simple BP neural network model can be applied in practice. Some feasible solutions are provided for improving the charging safety of electric vehicles.
Analysis of reactive power compensation of railway 20kV primary through line
Authors: Guo Wenlong , Tian Mingxing
Published: June 2022

With the increase of power load along the railway and stations and the popularization and use of 20kV distribution network, it has a great impact on the selection of voltage level of railway power supply. To solve this problem, the capacity rise effect of power through line, reactive power compensation capacity configuration of 10kV and 20kV Voltage levels are calculated and analyzed, and the MATLAB simulation model is established for simulation verification.
A Design of Tunable Filter Integrated SPDT Switch Based on PIN Diode
Authors: Jing Yuxiang , Cui Hengrong
Published: June 2022

In this paper, a tunable filter integrated SPDT switch based on PIN diode is proposed. The band-pass filter response is realized by using microstrip lines with different characteristic impedances, and the filter-integrated SPDT switch with tunable center frequency is designed by loading a varactor diode and PIN diodes. The measured results show that its filter response can be tuned in the range of 1.5 to 2.065 GHz, the insertion loss is 1.53-2.69 dB, and with well return loss and port isolation.
Power Quality Indices Online Prediction Based on VMD-LSTM Residual Analysis
Authors: Xu Da , Hu Xiaoyuan , Hong Wenhui , Li Mengshi , Chen Ziming
Published: June 2022

In order to ensure the provision of high-quality power quality and the smooth operation of the power system, aiming at the problem of low prediction accuracy of power quality indices, this paper proposes an online prediction method of power quality indices based on VMD-LSTM residual analysis. Firstly, the VMD-LSTM is used to simulate and predict the normal power quality signal; then the predicted signal data is different from the actual power quality signal data to obtain the residual signal, and the residual signal is input into the one-dimensional convolutional neural network for training, and finally the power quality indices prediction model is obtained. Finally, taking voltage flicker as an example, simulation experiments compared with other prediction models verify the better effectiveness and accuracy of the proposed method.
Research on thermal resistance Measurement method of high power LED
Authors: Fu Qiang , Zhang Junchao , Zhang Jie
Published: June 2022

Due to the special packaging and working conditions of high-power LEDs, it is a huge challenge to accurately measure the junction-to-case thermal resistance. The traditional transient dual interface and structure function methods have been successfully applied to measure the thermal resistance of high-power LEDs. In this paper, a different interface condition is designed to change the contact thermal resistance between the DUT and the heat sink, making the Z
th curve separation point clearer. More importantly, the structural thermal resistance between multiple layers on the heat flow path of the device is obtained by converting the Z
th curve. Finally, the effectiveness of the method is verified by comparative analysis of experimental data.
Research on a Microwave Filter with Pentagram Grooves
Authors: Hou Y F , Qian J
Published: June 2022

This paper introduces a microwave filter with pentagram grooves, which belongs to an artificial surface plasmon (SSPPs) type microwave bandpass filter.The filter adopts a two-stage structure. The first section is a slot-line waveguide section, and one side of this section adopts an exponential curve structure to prevent sudden changes in electromagnetic impedance and achieve a good connection with the second section.The second segment is the SSPPs segment, which adopts a novel mirror-symmetric pentagram-shaped groove air gap structure. By adjusting the geometric size of the pentagram-shaped groove, the microwave subwavelength confinement effect can be further improved,making the SSPPs filter more excellent in pass-band characteristics and anti-space electromagnetic interference.The filter can be applied to the civil microwave communication system of L∼S band.
Research on Optimization Simulation of Three-level Inverter in UPS Based on PSO Algorithm
Authors: Li Xiaoqian , Zhang Guichen , Zhang Qi
Published: June 2022

As a kind of precision power equipment, the uninterruptible power supply system (UPS) can supply power to the load through a DC-AC converter to ensure the uninterrupted power supply in case of grid failure. The voltage waveform output by the inverter has a decisive effect on the power quality, performance of the UPS system is determined by the power quality. Therefore, this paper aims to optimize the output power of the inverter from two aspects: on the one hand, the three-level space vector pulse-width modulation (SVPWM) technology is combined with the double closed-loop control system to improve the voltage waveform of the inverter; On the other hand, the PI parameters in the double closed loop are optimized by the particle swarm optimization (PSO) algorithm, the dynamic performance of the system is optimized, the adjustment time and overshoot are reduced, thus the control performance of the UPS system is improved.
The online diagnosis of internal insulation fault of capacitance voltage transformers based on machine learning
Authors: Wei Wei , Peng Tao , Fang Yi , Ye Li
Published: June 2022

In order to diagnose internal insulation faults of CVT in time, an online diagnosis method for the internal insulation performance of CVT is proposed in this paper. The relationship between CVT insulation performance and measured data is obtained by analyzing CVT internal insulation structure and transfer function. After constructing an appropriate eigenvector by the inter-group correlation amplitude parameter of CVT, three methods of SVM, Bayes, and KNN are used as classifiers for insulation fault diagnosis. The experiment result shows that KNN method can effectively diagnose internal insulation faults with an accuracy rate of 100%.
Analysis and Research on the Reasons for the Increase of Com ponents in 500kV Transformer Oil
Authors: Li Rui , Chen LiangYuan , Li DaJian , Zhang Lei
Published: June 2022

This paper analyzes the cause of the defect of component growth in a 500kV transformer oil. First, the historical operation of the main transformer is analyzed, and then the oil chromatography data is studied. The A-phase online chromatography shows that the acetylene content is in good agreement with the offline chromatography detection, showing an increasing trend. The disintegration inspection of the main phase A phase found that there were two obvious discharge breakdown points in the inner paper tube of the low-voltage coil. According to the analysis results, the A-phase transformer should be managed and controlled, especially the oil chromatography tracking period (once every two weeks) should be shortened, and the load should be controlled if necessary.
Research on cross-region interconnection detection method of abnormal data in power monitoring system
Authors: Bin Dongmei , Ling Ying , Yu Tong , Yang Chunyan , Liu Muxian , Chen Haiguang
Published: June 2022

When conventional methods collect cross region interconnection detection data of power monitoring system, one data has multiple signal strengths, resulting in low detection rate and high false alarm rate of cross region interconnection abnormal data. Therefore, a cross region interconnection detection method of abnormal data in power monitoring system is proposed. Divide the cross region interconnection scene types of power monitoring system, make the detection end send data packets to the security partition corresponding to different scenes, and Gaussian filter the signals received in the security partition, and only retain the signals with probability distribution density function of [0.5,1]; Convert multiple signal strength indications of MAC address into one, so that the security partition only responds to the MAC address, obtains the MAC address detection data, and inputs it into the deep confidence network after preprocessing. If the MAC address matches successfully, it is judged that there is cross region interconnection in the power monitoring system, and the cross region interconnection detection of abnormal data is completed. The cross region interconnection alarm data provided by a power Co., Ltd. is selected as the experimental data, and the comparative experiment is set. The results show that the design method improves the abnormal data detection rate, reduces the false alarm rate, and ensures the detection accuracy of large-scale cross region interconnection data.
Analysis of evaluation index for the electron laminar properties in the electron optical system
Authors: Zhang Jian , Geng Zhihui , Jin Qi
Published: June 2022

In the simulation of the electron optical system of vacuum electronic devices, the evaluation of the electron laminar properties can only be judged by observing the electron trajectories. The quantitative evaluation index parameters for the electron laminar properties is lacking in the electron optical software. To achieve a quantitative analysis of the electron laminar properties in Egun simulations, the crossover rate evaluating the laminar properties of electron properties is presented in this paper. The simulation results show that the crossover rate index can accurately and quantitatively evaluate the quality of the electron laminar properties. When the crossover rate of electron properties is less than 3%, the designed electron optical system meets the engineering requirements. The crossover rate can be used as the target parameters in the automatic optimization of electron optical system.
Research on Plug and Play Implementation Technology for Distribution Network Equipment
Authors: Song Yinghua
Published: June 2022

From the point of view of primary diagram, secondary equipment and Model Association of distribution network, this paper studies Plug and Play technology of distribution network equipment from access to application, describes the advantages and disadvantages of different technologies, and provides development ideas for future construction of distribution automation.
Research on performance parameter degradation of high voltage and high power IGBT module in power cycling test
Authors: Li Cui , Sheng Li Yao , Xu Liu Jun , Qiang Shao Hua , Chen Zhong yuan , Yuan Li Jin
Published: June 2022

In Power cycling test, for low-voltage and low-power modules, it is generally considered that the saturation voltage drop VCE(sat) reaches 105% of the initial value or the thermal resistance Rth reaches 120% of the initial value as the basis for judging the failure of the IGBT module. However, since the high-voltage and high-power IGBT modules are connected in parallel with multiple chips, there are differences in the aging speed of the chips, and the degradation of individual chips has little influence on the parameters of the entire module, so the failure judgment standard may not be applicable. In order to obtain the degradation of the characteristic parameters of the high-voltage and high-power IGBT module in the power cycle test, this paper selects the 6500V/600A IGBT module as the research object, adopts the experimental method of constant junction temperature fluctuation, and tests the module parameters after every cycle 20,000 times until the module fails. Three failure modes were found through the test: GE failure, CE failure, GE and CE failure. And the degradation law of the parameters of the high-voltage and high-power IGBT module during the power cycling test was obtained.
System design and research of multi-channel electroacupuncture instrument
Authors: Liang Chuanqi , Zhang Yulin , Li Yan
Published: June 2022

This paper introduces the development history, working principle, curative effect under different output waveforms and the hardware and software design of the system. The proportional constant current output circuit is analyzed in detail. A system structure of electroacupuncture instrument based on modular design is proposed. The system structure mainly includes multi-channel electroacupuncture control module and display control module, which are connected through CAN bus. Multi-channel electroneedle control module adopts embedded processor and real-time operating system design, display control module is application level processor, running embedded Linux system design. The system has reasonable structure design and high expansibility, which is convenient for further research.
Design of Parallel Hybrid Active Power Filter
Authors: Wang Yan , Yang Ruijie
Published: June 2022

With the rapid development of social economy, electric energy plays an indispensable role in social life and has become an important symbol of the country’s comprehensive national strength. However, with the rapid development of power electronic technology, many nonlinear loads appear in the power system, which has become the most important harmonic source in the power system. Harmonics will not only affect the normal operation of various electrical equipment, but also damage the peripheral communication system and equipment of public power grid. Therefore, we must control the harmonics in the power grid. The traditional treatment scheme is to use LC passive filter (PF), but it can only filter out harmonics of a specific number of times. In addition,it is sensitive to power grid parameters, may produce resonance, so that the harmonics are amplified, and the volume of the filter device is huge. In order to overcome the above problems, active power filter (APF) appears, which can dynamically compensate harmonics according to harmonic frequency and size, and has excellent flexibility and practicability. However, in terms of cost, the cost of APF with the same capacity is much higher than that of PF. Therefore, based on the respective characteristics of PF and APF, this paper makes an in-depth research and design of hybrid active power filter (HAPF). In this system, the passive filter completes the main harmonic compensation and reactive power improvement, while the active filter is used to help the passive filter overcome the disadvantage of easy resonance.
Research on Photoelectric Detection Performance Based on Pb Se Quantum Dots
Authors: Liu Hao , Yang Junhong
Published: June 2022

Quantum dot materials have the advantages of low cost, wide spectral response and good photostability, and are widely used in optoelectronic fields such as light-emitting diodes and photodetectors. Quantum dots are the key materials for the next generation of new semiconductor optoelectronic devices. The direct integration of nano-quantum dots with silicon-based materials can simplify the fabrication process of optoelectronic devices. The environmental stability of lead selenide (PbSe) quantum dots is poorer than that of lead sulfide (PbS) quantum dots, which limits its application in optoelectronic devices. In this paper, we combine lead selenide quantum dots with silicon-based photovoltaic junction field effect transistors, and introduce halides in the synthesis process to improve the stability of quantum dots in air. We analyze and study the performance of this new type of near-infrared quantum dot photodetector, and study the influence of factors such as channel area and quantum dot size on the performance of the detector, which provides ideas for further optimizing the photodetection performance.
Analysis of defrosting system failure of ship low temperature cold storage
Authors: Wang Yanyang , Hu Linxiang , Wang Heng , Liu Chongchong
Published: June 2022

The frosting of the evaporator of the ship’s low-temperature cold storage will affect the heat exchange performance of the evaporator operation, the stability of the low-temperature cold storage of the ship’s food security and the effect of food refrigeration. Therefore, the evaporator coil of the low-temperature cold storage needs to be defrosted regularly. The low-temperature refrigeration system of a ship adopts the defrosting mode of electric heating. The lower the temperature of the low-temperature warehouse, the more important the thermal effect of defrosting is. This paper puts forward a technical innovation scheme for the design of the ship’s cold storage and the defrosting control mode, which can provide a reference for the design of the ship’s low-temperature refrigeration system and the defrosting of the low-temperature cold storage.
Study on Single Crystal Holmhertz Underwater Acoustic Transducer
Authors: Chen Geng , Liu Hao
Published: June 2022

According to the theoretical calculation and finite element simulation, a Holm-Hertz transducer is designed. When the resonant frequency of the outer liquid cavity of the transducer is consistent with the resonant frequency of the piezoelectric ceramic stack, the maximum transmit voltage response(TVR) is obtained. After the electrical material was replaced with a new relaxation ferroelectric single crystal piezoelectric material PIN-PMN-PT, the resonant frequency of the transducer was reduced, and the liquid cavity structure was redesigned. Single crystal, can significantly reduce the resonant frequency of the transducer, while significantly increasing the transmit voltage response.
Ultra-Broadband Full-Space Function-Integrated Stealth Antenna System Based on Metasurface
Authors: Wang Zan-Yang , Wang Guang-Ming , Cui Xing-Shuo
Published: June 2022

In this paper, an ultra-broadband full-space function-integrated stealth antenna is proposed based on metasurface (MS). After x-polarized and y-polarized spherical wave passing through the MS, the MS converts the y-polarized spherical wave into the x-polarized vortex wave in transmission space, deflects and focus the x-polarized spherical wave into x-polarized plane wave in reflection space simultaneously. Moreover, when y-polarized wave illuminates the MS in transmission space, the MS achieves scattering control on the y-polarized reflected wave to realize the diffuse scattering function. Exciting the MS with a horn antenna, the broadband antenna system with full-space function-integration and low backward RCS is realized. The antenna system achieves high-gain vortex wave radiation in transmission space, and high-gain beam frequency scanning in reflection space. Besides, when y-polarized wave illuminates the antenna array in transmission space, diffuse scattering stealth is achieved. Experimental results show that the 3 dB gain relative bandwidth of the vortex wave antenna in the transmission space is 67% (10∼20 GHz), the 3 dB gain relative bandwidth of the frequency scanning antenna in the reflection space is 54% (11.5∼20GHz), and the scanning angle covers 31°. The antenna backward RCS reduces more than 10dB between 11.7 GHz to 20 GHz.
A Low Profile, Broadband Circularly Polarized Beam Scanning Array
Authors: Zhao Ming-Yang , Lei Xue , Zhu Yi-Jun , Peng Qiang , Tang Zhao-ying , Fu Yi-yuan
Published: June 2022

Based on the idea of tightly coupled dipole array, a low profile, broadband circularly polarized array is designed in this paper. The circularly polarized phased array element consists of dual polarized dipoles with the same phase center and orthogonal arrangement, grounded coupling patches, resistive frequency selective surfaces (RFSS), and a 90° phase shifter network. In order to realize broadband scanning, the effect of RFSS on the input active voltage standing wave ratio and radiation axial ratio (AR) of the element is studied. The results show that the element can operate at 5-11.5GHz, within a ±45° angle scanning range, the AR of each scanning plane is less than 3dB, and the profile height is only 0.33 λ
high.
An Improved Method for Antenna and Probe Alignment in Auto-calibration of Millimeter-Wave Digital Monopulse Radar
Authors: Zheng Yu , Yao Chen , Zhao Guoqiang
Published: June 2022

Calibration is an effective method for improving digital monopulse radar tracking performance since it can eliminate the amplitude-phase imbalance between channels. Fast and accurate alignment between the antenna under test and the probe is an important part of the calibration. however, the narrow beam and high gain of a millimetre-wave band antenna pose a challenge to the alignment. To tackle this problem, we propose an improved alignment method based on the gradient feature of the radar radiation pattern. The method incorporates adaptive moment estimation to resist noise in the iteration process of the alignment. The high-accuracy alignment of the proposed method is verified by simulation and experiment. The root mean squared error of the alignment of the proposed method is 0.0046 degree in the absence of noise. At the SNR of 30 dB, the root mean squared error of the alignment is 0.008 degree. The proposed method improves the calibration efficiency and thus has a broad application prospect.
Research on Maximum Efficiency Output Control of Voltage Controlled Adjustable Constant Current Source
Authors: Yu Yingbo , Kang Zhongjian
Published: June 2022

Voltage controlled adjustable constant current source has simple structure and high output precision, but its high switching power consumption and low output power efficiency under current variation hinder the development of its high current application. A maximum efficiency output control method of constant current source based on small signal model is presented to reduce switching loss and achieve high efficiency output. A 0-4A adjustable constant current source prototype was built to verify the theory, and the experimental results show that when the setting current changes from 1 to 4A, the output dynamic response of the experimental group is rapid, the instantaneous peak power of MOS transistor is only 6.04w, and compared with the control group, the average efficiency of the system is from 85.85% up to 92.86%, which indicate a better power consumption control ability.
Design of a Novel Dual-band Dual-circularly Polarized Waveguide Slot Array Antenna
Authors: Tian Si-Yu , Lei Xue , Wang Hai , Zhao Ming-Yang , Gao Jun , Li Tian-Peng
Published: June 2022

A novel dual-band dual-circularly polarized waveguide slot array antenna is designed. The antenna opens two orthogonal slots with different lengths on the standard waveguide and is excited at two frequencies. The electric fields of TE10
and TE01
modes are obtained. To achieve the purpose of dual-band dual-circular polarization. Two orthogonal slots can not only make the antenna elements have slow-wave properties and delay phase, but also make the antenna elements in different frequency bands have the same virtual short-circuit wall, which simplifies the difficulty of design and processing. The antenna can achieve an equidistant array and become an array antenna. Through simulation verification, the S11<-10 dB in the two frequency bands from 11 GHz to 11.3 GHz and from 13.1 GHz to 13.8 GHz. In this bandwidth, the axial ratio bandwidth is less than 3 dB, respectively. The isolation between the two ends is better than 12 dB, and it has left and right circular polarization. The problem of the deterioration of the axial ratio of the circular polarization of the antenna caused by the different phases between the waveguide slot antennas is solved.
Research on the Propagation Characteristics of High Frequency Partial Discharge Signal in Transformer
Authors: Li Yang , Tang Zhiguo
Published: June 2022

In order to study the information contained in the high frequency partial discharge and the influence of transformer winding on the propagation of partial discharge signal, this paper injects high frequency small signals into the external leads, internal winding and enclosing screen of 110kV three-phase double-winding transformer to simulate the external discharge, inside and outside of the winding discharge to study the propagation characteristics of transformer partial discharge signal. The study shows that the partial discharge signal is coupled from one to others, and the signal can be detected at each detection end when partial discharge occurs; the partial discharge signal consists of high-frequency component and low-frequency component, the high-frequency component is mainly propagated through the capacitance between the windings, and the low-frequency component is mainly propagated through the windings; The polarity of the first wave of the time domain signal is different when the discharge of the internal winding of the transformer propagates to each detection point, the polarity of the first wave of the time domain signal is the same when the discharge of the outside winding propagates to each detection point. Among them, the discharge of the outside winding mainly propagates through the capacitor, and the low-frequency components of each detection terminal are seriously attenuated.
Design of an Aerospace Langmuir Probe Volt-ampere Characteristic Load Simulator
Authors: Zhao Zhendong , Wang Yi , Zhou Ying , Chen Guangfeng , Hu Xiangyu , Zhang Haiyan
Published: June 2022

The development process of space Langmuir probe needs to complete a large number of tests and calibration tests on the ground. Due to the long calibration period, complexity and high cost of plasma environment calibration, calibration tests are usually carried out after the instrument has been developed, in order to conduct preliminary tests on Langmuir probe during the instrument development process to verify the performance, as well as to save the cost of calibration tests and increase the reliability of the instrument, An advanced spatial Langmuir probe volt-ampere(I-V) load simulator was designed in this paper. Based on the positive and negative polarity of the external bias voltage, the I-V characteristic curve of the Langmuir probe was divided into positive and negative characteristic curves, which were realized by the combination of the output characteristic curves of NPN and PNP transistors, and the diode switching selectivity. The laboratory test results were consistent with the theoretical curve, verifying the validity and compliance of the design, which can play an important role in supporting the development of the space Langmuir probe and the calibration of the plasma environment.
Multi-sensor time synchronization algorithm based on Gaussian process regression
Authors: Yang Quan , Zhao XuanZhi , Zhang Wen , Jin WenJun
Published: June 2022

In order to address the problem of inconsistent sampling frequency and accuracy of each sensor in multi-sensor data fusion technology, the algorithm of Gaussian Process Regression (GPR) is proposed for time alignment, and in the scenario where the target motion model is uniform linear motion and uniform turning motion, the simulation is compared and analyzed respectively. The simulation results show that the proposed algorithm can effectively improve the accuracy of time synchronization.
Application of two spectrum refinement methods in frequency estimation
Authors: Deng Leilei , Leng Kaijing
Published: June 2022

Considering the limitation of FFT frequency estimation method in resolution, this paper briefly introduces the complex modulation ZOOM-FFT and Chirp-Z transform spectrum zooming methods. The simulation results show that the ZOOM-FFT method has better anti spectrum leakage and interference effect. Furthermore, the two methods are applied to the frequency estimation of underwater high-speed maneuvering target, and it is found that Chirp-Z transform method can obtain smoother and stable frequency history, and has more flexible frequency resolution.
Research on attitude control strategy of unmanned helicopter based on hybrid particle swarm optimization algorithm
Authors: Liu Zhiqiang , Ye Xi , Qian Tonghui , Yu Linwen
Published: June 2022

For the unmanned helicopter attitude control problem, an optimal control strategy based on hybrid particle swarm optimization (PSO) algorithm has been proposed. Firstly, a coupled dynamics model of the system has been established based on the structural characteristics of the unmanned helicopter system; secondly, a gain scheduling control method has been adopted to select multiple system stable operating points with real-time error as the scheduling variable, and a gain scheduling attitude controller has been designed; further, the inertia weights and learning factors are dynamically adjusted on the basis of the traditional PSO algorithm, and a hybrid PSO algorithm has been proposed for unmanned helicopter attitude control; finally, the improved controller has been compared and verified by the semi-physical. The experimental results show that the improved algorithm improves the attitude control effect and anti-interference capability of the unmanned helicopter, resulting in a reduction of the adjustment time by about 3.8s and the maximum steady-state amplitude by about 0.154°.
Identity and body temperature detection system based on image registration
Authors: Yao K , Chen Y , Zhang Z D , Li G , Zhai J B , Liu Y H , Zhou J L
Published: June 2022

In view of the normalization of epidemic prevention and control work, the low detection efficiency of traditional temperature measurement methods, and the existence of infection risks, an infrared thermal imaging temperature measurement system that can measure and identify the temperature of more than two people is designed. The system uses the Raspberry Pi as the core controller, using visible light and infrared cameras to capture identity and body temperature information. Identity recognition is based on OpenCv, using the Face Recognition face recognition framework to complete the identity recognition; body temperature detection is based on image registration, and the face position is mapped to the infrared image in real time through affine transformation, and finally the temperature of the human face area is obtained and displayed on the screen. The final experimental results show that it can simultaneously identify multiple people and detect body temperature with high accuracy, which can basically meet the requirements of rapid body temperature screening in intensive situations.
LADRC Based Digital Control DC-DC ASIC Design
Authors: Zhang Wangdong , Fan Bo , Lu Chao , Liu Huimin
Published: June 2022

The Internet of Things (IoT) systems require power management modules to have the characteristics of low power consumption, high conversion efficiency, high integration, stable output, and good dynamic response. Due to its ease of tuning and superior control performance, linear active disturbance rejection control (LADRC) is an attractive design option. Yet, to date, due to its high complexity, LADRC has been used in software systems, while little effort has been made in its hardware implementation. In this work, we investigate and explore efficient hardware implementation of the LADRC algorithm. A fully integrated digital LADRC controller for DC-DC Buck converters is synthesized with UMC 55 nm CMOS process. Its input voltage is 5V, stable output voltage is 2V, and rated operating current is 100mA. To our best knowledge, this is the first work to implement LADRC algorithms in hardware. Simulation results show that the LADRC controller is superior to the PID controller in the terms of start-up time, line regulation, load regulation.
Detection of Weak Pulse Signal under Chaotic Noise based on Fractional Maximum Correlation Entropy Algorithm
Authors: Su Liyun , Shi Lin , Li Fenglan , Quan Jing , Zhao Shengli
Published: June 2022

How to improve the detection accuracy of target weak signal is always the difficulty of signal processing. In this paper, based on fractional maximum correlation entropy algorithm and combined with the local linear model, a method for detecting weak pulse signal in chaotic noise background is proposed. Firstly, for the sensitivity of chaotic signal to initial values and short-term predictability, reconstruct the phase space of the observation signal, establish a local linear model, use the fractional maximum correlation entropy algorithm for parameter estimation, and perform a single-step prediction to obtain the prediction error. Then, in order to accurately detect the submerged weak pulse signal, a threshold is given. Finally, the simulation results show that the proposed model in this paper can effectively detect the weak pulse signal under the background of chaotic noise, and it is suitable for signals of different intensities, and the detection speed and accuracy are much better than other models.
Radio Frequency Identification target location based on the Unmanned Aerial Vehicle
Authors: Liu Yulin , Zhou Jian , Wang Lin , Wang Yu , Yin Yong , Ding Zhongjun
Published: June 2022

Due to the complex environment, the traditional Radio Frequency Identification (RFID) localization algorithm is cumbersome, the system localization accuracy is low, and the calculation time is relatively complex, an RFID localization algorithm based on sequential Kalman filtering has been proposed in this paper. Through the flight of sequential points, The Unmanned Aerial Vehicle (UAV) with the reader collects the Received Signal Strength Indication (RSSI) data dealt with mixed filtering of the target in the scene, after obtaining the coordinates according to the three-ball intersection method, and then using the Unscented Kalman Filter (UKF) algorithm to generate the estimation equation, thereby determining the position trajectory information to estimate. The results show that compared with other positioning methods the system has higher mobility and improved positioning accuracy with an average of 13.15%. At the same time, due to the real-time and flexibility of drones, this system can also be applied to more diverse scenarios. And the algorithm operation time is 1.15 s and it is suitable for UAVs scenarios.
A strategy dedicated to the concise and efficient development of the customized large-signal model for GaAs HEMTs
Authors: Zhu Huabing , Yan Zhihai , Tian Weiqian , Zhao Hong , Song Cheng , Zhang Lin , Hu Bin
Published: June 2022

In this letter, a strategy dedicated to the concise and efficient development of the customized large-signal models for GaAs HEMTs is proposed, which is specialized for MMIC designers. The core concepts of the strategy are a deconstruction of the original thought of model construction and dimension reduction of the objective functions of optimization algorithms. The development of an Angelov-based customized large-signal model following this strategy has been successfully applied to GaAs HEMTs in 70nm process. The results show that it takes less than five minutes to execute such a parameter extraction algorithm with a one-button extraction function and good agreement is achieved between the model simulation and device measurement up to 65GHz.
MIMO Radar Imaging Based on Two-dimensional Compressive Sensing Recovery Algorithm
Authors: Feng Junjie
Published: June 2022

Conventional sparse signal recovery-based MIMO radar imaging method rearranges the received two-dimensional (2D) signals into a vector, However, transforming the two dimensional equation to one dimensional equation then solving linear equation based sparse signal recovery problem requires huge memory and computational budget. A two-dimensional compressed sensing MIMO radar imaging algorithm based on improved smooth L0 norm is proposed in this paper. Firstly, a two-dimensional MIMO radar imaging model is established to transform the imaging problem into a sparse optimization problem. Then, the two-dimensional negative exponential function sequence is used as the smoothed function sequence to approximate the L0 norm. The two-dimensional imaging of MIMO radar is realized by cyclic iteration and gradient projection algorithm. Simulation results show that the proposed algorithm has advantages over the traditional compressed sensing algorithms.
A test method for active reflection coefficient of array antenna
Authors: Zhao Hongyi , Shi Guangqin , Ma Fengjun , Zhang Yi , Wei Yinyu
Published: June 2022

The mutual coupling effect of array antenna can usually be characterized by the dominance of active reflection coefficient. A test method of active reflection coefficient is proposed in this paper. the theory of antenna active reflection coefficient is analyzed, and the array antenna modeling and active reflection coefficient simulation results are introduced by HFSS. the hardware composition and function of antenna active reflection coefficient test system are introduced. the comparison between test results and simulation results is analyzed. The results are in good agreement. Compared with the traditional test methods, the designed test system has the characteristics of intuitive test results, fast measurement speed, high sensitivity, large dynamic range, small measurement error and strong expansibility.
Compensation of Position Estimation Error in PMSM Sensor-less Control Based on High Frequency Square Wave Injection
Authors: Zhao Xince , Su Jianyong , Wang Shuai , Yang Guijie
Published: June 2022

The high-frequency square-wave injection method is widely used to estimate rotor position at low speed. However, the accuracy and reliability of the method are greatly affected by the dead-time effect. The specific expression of position error is deduced. On this basis, a dead zone error reduction method based on second-order general integrator (SOGI) is adopted to improve the accuracy of position estimation. Besides, low-pass filter needs to be introduced into the current loop, which will bring delay to the system. Aiming at this problem, a delay compensation algorithm is adopted, which can effectively improve the accuracy of position estimation. Results of simulation verify the effectiveness of the methods and their applicability to PMSM sensorless control systems.
An Efficient Multi-dimensional Data Aggregation Scheme for Fog-Assisted Wireless Body Area Network
Authors: Fan Hongbin , Luo Yiheng
Published: June 2022

The rapid development of wireless body area network and monitoring technology has brought new opportunities for the later rehabilitation of patients. Due to the limited computing power and power of wireless body area network (WBAN) sensor nodes, combining WBAN with fog computing is one of the feasible solutions for remote monitoring. Wireless body area network can exchange medical information in real time, which is an effective way to improve medical services. The WBAN is inefficient and vulnerable to attacks, leading to leakage of user privacy information. This paper proposes an efficient data aggregation scheme for fog-assisted WBAN. The analysis shows that the scheme can resist the existing attack. The security analysis shows that the scheme meets the privacy and security requirements of data aggregation in WBAN. Compared with existing schemes, this scheme has an efficiency advantage.
Numerical Calculation of Vibration Characteristics of Transformer Core under Inter-harmonics
Authors: He Qiang , Fan Chao , Yang Guang , Li Huiqi , Li Jiadong , Chen Xiaogang
Published: June 2022

In this paper, a numerical model that can simulate the vibration of the transformer core under arbitrary inter-harmonic excitation is established. On this basis, the influence of interharmonics on core vibration is studied. First, based on the multi-physics coupling software, by deriving the differential equations of the physical fields, a coupling model of the circuit, magnetic field and solid mechanics is established. Then the magnetostriction curve is used to calculate the magnetic flux density and vibration displacement of the transformer core model under power frequency sine and interharmonic excitation. The work of this paper lays a theoretical foundation for studying the vibration problems of power transformers and other equipment under inter-harmonics.
Research on Short-term Load Forecasting Based on GWO-BILSTM
Authors: Liu Zhaosu , Yang Jianfeng
Published: June 2022

In short-term power load forecasting, changes in external multi-dimensional factors will have a certain impact on the accuracy of load forecasting. In response to this problem, this paper proposes a prediction model GWO-BILSTM that combines the Grey Wolf Optimizer (GWO) and the bi-directional long short-term memory (BILSTM) network. Taking the real power load data as the data set, the high correlation parameters are selected as the input through the Pearson correlation analysis, the hyperparameters of BILSTM are optimized by the GWO algorithm, and finally the GWO-BILSTM prediction model is established based on the optimized parameters to predict the data set. The experimental results show that the mean absolute percentage error, root mean square error and mean absolute error index of the GWO-BILSTM model are better than other comparison models, which effectively improves the prediction accuracy of multi-dimensional power load data.
Analysis and calculation of beam-wave interaction in 220GHz gyrotron resonator
Authors: Su YunFeng , Zhao Ding , Liu Qiang
Published: June 2022

In this paper, the beam-wave interaction of the 220GHz gyrotron resonator is analyzed. The design scheme of the physical structure of the TE36,17 cylindrical open resonator is given. According to the beam-wave coupling coefficient, the center radius of the electron beam guidance of the resonator is obtained, and the working parameters of the resonator are determined by the start current. The single-mode self-consistent nonlinear theory in the frequency domain of the resonator is deduced, and the output characteristics of the resonator are studied by using MATLAB.