bluuebunny/crossref_metadata_2025 huggingface dataset:
Torque anomaly detection of nuclear power electric valve actuator based on DAE-WDSVVD
Authors: Peng Junjie , Chen Xin , Li Mingqiang , Zhang Yanhui
Published: February 2022

The abnormal detection of nuclear power electric valve actuator components can effectively improve its operation safety and reliability. With the rise of artificial intelligence technology, data-driven fault diagnosis methods have become more and more popular. However, in practical application, there are few or almost no fault data of valve actuator. For the problem of anomaly detection of actuator components of valve in the scenario of only normal data, anomaly detection method based on the fusion of deep autoencoder (DAE) and weighted deep weighted support vector data description (WDSVVD) is proposed. It uses normal data to train the depth self-encoder, and the reconstruction error of the depth self-encoder to train the support vector data description. Compared with the traditional anomaly detection method, it significantly improves the anomaly detection accuracy and can realize more sensitive and robust component anomaly detection.
Research and Application of a Fast Recovery Strategy for Complex Structure Networks Based on Sorting Multi-objective
Authors: Dang Yijie , He Yunrui , Zhang Shulin , Chen Liang , Liu Guangxu , Zhang Xiangyi , Bai Shuo
Published: February 2022

With the development of information technology, the scale of data centers and the number of equipment are experiencing explosive growth, and the network structure of data centers has also continued to develop and mature. The more complex network structure increases the possibility of network failures and the difficulty of operation and maintenance. When an unpredictable failure occurs in the network, in order to quickly recover the network, a multi-objective complex structure network rapid recovery strategy is proposed. Under the goal of the shortest failure time, minimum reduction of safety protection, and maximum possible restoration of the original method, a restoration plan is given.
Cold-preventing simulation of low-temperature protective clothing based on an unsteady one-dimensional heat conduction model
Authors: Wang Sizhong , Luo Yuhao , Li Zhenyang
Published: February 2022

With the development of science and technology, people are constantly exploring the extreme cold regions. In order to enable people to work normally in extremely cold weather, scientists have been studying low-temperature protective composite materials to protect workers in ultra-low ambient temperatures. This paper studies the cold-proof effect of low-temperature protective clothing composed of three materials. First of all, this paper uses the principle of heat transfer to establish an unsteady one-dimensional heat conduction partial differential equation model for the experimenter, cryogenic protective clothing and the system composed of the external air environment. Secondly, this paper determines the boundary value conditions and boundary value conditions of the definite solution, as well as the continuous conditions of the contact surface between the materials in the protective clothing. On this basis, this paper uses the finite difference method to convert the differential equation into a display format to solve the problem. The final result is that the experimenter’s persistence time with 15°Cas the holding limit outdoors is 662.5s, and 10°Cas the holding limit. It is 675.3s. Finally, the sensitivity analysis of the model is carried out by setting the temper-ature fluctuation.
Firefly optimized particle filter algorithm based on adaptive differential evolution
Authors: Meng Ziwei , Mei Jinjie , Yu Chengjun
Published: February 2022

The improved particle filter algorithm based on fireflies reduces the particle diversity in the later iterations, which is easy to fall into the problem of local optimization. To solve the problem, after firefly position updated, we can integrate the differential evolution algorithm into it. The process can be described like this: firstly, the mutation process is guided by the particle weight adaptively; the crossover process is selecting individuals randomly according to the crossover probability; finally, the selection process takes the observation probability density function as the fitness value, and retains individuals with high fitness. After adding differential evolution, the diversity of individuals has increased and jumped out the process of local optimization. The overall quality of the particle swarm has been improved. Experiments show that the tracking accuracy of the improved algorithm has been improved, as well as the global optimization capabilities.
Production Bottleneck Prediction of Multi-Variety and Small Batch Production Workshop
Authors: Lin Shuo , Liu Junhui , Li Shishi
Published: February 2022

Aiming at the bottleneck dynamic drift problem of production line, a dynamic bottleneck prediction method based on Markov chain was proposed to predict the bottleneck before the bottleneck appeared and predict the bottleneck change state. First, Markov state probability transition matrix is determined by analyzing the past data. Second, the current operation state of the process is brought into the Markov chain to calculate the probability of each process bottleneck at the next moment. Finally, the bottleneck index model is used to accurately locate the bottleneck location, and then get the exact bottleneck process.
Calibration and Target Signal-to-Noise Ratio Enhancement Method of Infrared Camera Array Based on Refocus
Authors: Xie Xiaokai , Yang Jungang , Xiao Chao , Wu Tianhao , Liu Ting , An Wei
Published: February 2022

The accuracy of infrared (IR) camera calibration directly affects the quality of IR imaging results. Many imaging devices have been utilized in infrared dim and small target detection, which is a major research direction in infrared field. Comparing with single-lens cameras, IR camera array can improve the detection capability by adding more imaging units, and is expected to break the limitations of traditional single-lens imaging system in cost, volume and performance. The calibration methods for camera array nowadays are generally applied in visible spectrum instead of IR band. In this paper, we proposed a calibration method based on refocus for IR camera array. Furthermore, the target signal-to-noise ratio enhancement method become effective after calibration of IR camera array. As the camera parameters obtained can be used to correct image distortion and improve the quality of imaging, the calibrating process can support many subsequent tasks such as target detection. Experiments indicate that our method achieves the expected effect.
Aero-engine Model Correction Technology Based on Adaptive Neural Network
Authors: Pu Chenghan , Zhou Wenxiang
Published: February 2022

In this paper, a neural network-based algorithm is proposed to adapt the performance maps of engine component models for the mismatches between aero-engine simulation models and actual engine characteristics. Based on the general characteristics data of rotating components in GasTurb, a neural network capable of calculating the efficiency and mass flow of rotating components is trained. This neural network is introduced into the engine nonlinear component model to calculate the deviation between the output parameter of each section of the engine component model and the real engine performance indicators. The linear relationship between the parameters of the nonlinear model is solved by applying perturbation theory. The error between the output characteristics of the neural network and the real engine component characteristics is derived based on the simulation error, which makes the neural network is further optimized so that it can track the current real engine performance. In this paper, a model of one turboshaft engine is used as the simulation object, and the simulation of component model building and performance maps adaptation is carried out. The simulation results show that the proposed performance maps adaptation algorithm can effectively improve the accuracy of the component-level model of the turboshaft engine, and is applicable to model correction of various types of gas turbine engines.
Balanced Scheduling Method for Big Data of Network Traffic Based on Set-pair Analysis Strategy
Authors: Yang Yijie
Published: February 2022

The continuous surge in the total amount of big data of network traffic leads to excessive data transmission load on the network channel. To effectively alleviate this problem, a scheduling method for regulating big data load is designed and proposed. The link discovery is applied to perform set-pair analysis of network topology awareness; the cloud computing algorithm is used to perform calculations for data transmission; based on the measurement results, traffic routing is controlled and measured to achieve link analysis and reorganization, as well as completing balanced scheduling of traffic big data, which proves that the method can effectively alleviate the big data scheduling load problem and has an important role for research in network optimization fields.
Hardware-in-the-loop simulation of inverter power supply controller based on StarSim and DSP
Authors: Zhou Han , Zhao Yongxin , Chen Guochu
Published: February 2022

Aiming at the contradiction between the requirements for rapid development and verification of inverter power supply controller products and the actual construction of real inverter power supply circuit topology, this paper proposes to build a semi-physical simulation platform based on StarSim and DSP. This paper takes the single-phase full-bridge inverter power supply as an example, use Shanghai ModelingTech company’s StarSim real-time simulator as the hardware platform, establish the circuit model in Matlab/Simulink and select NI PXIe-7846R board to run circuit extensions, and use TMS320F28335 as controller of the phase inverter power supply, based on StarSim HIL host computer program to load the model, configure the IO, and test and verify. The experimental results show that the semi-physical test platform has high accuracy and feasibility, shortens the development cycle of the controller, and greatly reduces the development cost of the controller.
Analysis of Responses of Satellite Honeycomb Panel to Pointwise Explosive Induced Environment
Authors: Liu Gang , Deng Mingle , Zhang Cheng
Published: February 2022

The purpose of this article is to research the pyroshock responses of a satellite honeycomb panel and to find a new method to characterize shock test specifications. The near-field and mid-field pyroshock responses induced by a pointwise explosive of the satellite honeycomb panel were measured using shock sensors. The responses were analyzed with haar continuous wavelet transform method, and a new method of characterizing shock test specifications with wavelet coefficients is proposed.
Research on feature extraction of steam turbine shafting vibration signal
Authors: Niu Qingliang , Gong Yuli , Tian Guocheng , Zhang Deke , Zhang Ming
Published: February 2022

Vibration signal feature extraction is the primary problem of steam turbine condition monitoring and fault diagnosis. This paper focused on the analysis and recognition of vibration signal feature extraction, carried out model innovation on the basis of the existing status, and studied new modeling and solution methods. The vibration fault signals of typical steam turbine shafting were described respectively, and the time-frequency characteristics were studied by wavelet analysis
An analysis of new materials and their effects on improving fuel efficiency
Authors: Li Anran , Qiao Yanchao , Fu Shenghong , Gu Yichen
Published: February 2022

This paper introduces the use of new materials in the replacement of traditional materials in automotive vehicles. Firstly, the properties such as tensile strength, elongation at break, Young’s modulus, density were discussed and analyzed. Also, the benefits of using new materials are discussed by comparing the physical properties. Then the advantages of AZ91D magnesium alloy, T1000G carbon fiber were compared with traditional automotive materials and the improvements that were achieved where the new materials were proven to have increased strength and decreased weight. Furthermore, the concept of automotive lightweight is applied to demonstrate the relationship between new materials and fuel economy. Finally, the internal and external structures of the materials are analyzed such as the anisotropy of carbon fiber, and it was found that the benefits outweigh the drawbacks like the high production cost of carbon fiber, then suggestions are given for future investigations.
Determination of 11 kinds of ultraviolet absorbents in plastic food contact materials by high performance liquid chromatography
Authors: Qiu Yue , Zhang Qing , Yang Qian , Tan Chanlan , Zhang Lu
Published: February 2022

A method for the determination of 11 kinds of ultraviolet (UV) absorbents in food contact materials was established based on high performance liquid chromatography. The target compounds were separated on a Agilent SB C18 (250 mm×4.6 mm×5 μm) column with gradient elution using acetonitrile and water as mobile phase, which analyzed by diode array detector and quantified by external standard method. The results showed that the linear range of the 11 UV absorbents was between 0.2 and 50.0 mg/L (R2≥0.9985), the limits of detection (LODs) were in the range of 0.01-0.05 mg/L, and the limits of quantification (LOQs) were 0.05-0.20 mg/L. The recoveries (R) of blank samples at 0.2, 10 and 50 mg/kg were from 80.2% to 97.5%, and the relative standard deviations (RSD) were ranged from 0.37% to 4.15%. The method had low detection limit, high stability and good repeatability, which could be used for daily detection of UV absorbents in food contact materials.
Progress and trend of PbTe based Thermoelectric Materials
Authors: Zhou Yeshiyuan
Published: February 2022

Energy shortage and environmental pollution have become severe problems that can not be ignored in every country. As a new energy conversion material, thermoelectric material can realize thermoelectric conversion with the advantages of safety, energy saving and environmental protection. This paper summarizes the progress of some PbTe based thermoelectric materials in recent ten years, including the influence of doping elements such as Na, S, Sr and I on their thermoelectric properties, and introduces a method to balance their mechanical and thermoelectric properties. It can be seen that PbTe based thermoelectric materials have good development and broad application prospects in the future.
The formation mechanism of the line segregation in twin-roll casting (TRC) 3003 aluminium alloy
Authors: Qian Xiaoming , Meng Longzhou , Sheng Xue , Li Yong , Wang Zhaodong
Published: February 2022

The formation mechanism of the line segregation in twin-roll casting (TRC) 3003 aluminium alloy was investigated. Results revealed that line segregations exhibited in the as-cast microstructures of 3003 TRC strips, depending on the different electromagnetic parameters, the position of the line segregations appeared at the center, lower, upper layers of the strips. The formation of the line segregations took place during the solidification, alloying elements were pushed towards and gathered at the center line and the resulted in the formation of the center line segregation. The dual-wave interference was the reason the changes of the position of the line segregation, when the weakened zone of the dual-wave interference appeared at the lower or upper layer of the melts, the position of the line segregation changed accordingly, when the weakened zone of the dual-wave interference appeared at the center line, the line segregation diminished.
Mn doped graphene aerogels for high capacity and long-life supercapacitor
Authors: Chen Zhi , Shan Shuang , Liao Jiaxuan
Published: February 2022

The pure graphene aerogel material is a double-layer capacitor material which provides capacitance by the surface area. Its conductivity and specific capacitance require further improvement. In this work, manganese doped graphene aerogels were synthesized by hydrothermal method using manganese chloride as a source of manganese. The effect of manganese content on the structure and properties of the material was studied. It is found that the specific surface area and pore volume of aerogels decrease with the increase of Mn content. The Mn doped graphene aerogel prepared at the current density of 0.1 A/g shows a capacitance of 180 F/g and exhibits pseudo capacitance performance in the three-electrode test. After assembling the button capacitor, the capacity retention rate is 93% after 1000 cycles at a current density of 0.5 A/g.
Analysis of microstructure and protective performance of melt-blown materials for medical protective masks
Authors: Zhang Jin , Wang Huipeng , Chen Chunliang , Gui An , Zhang Xiaoyu , Wang Yumin , Xiong Yi , Zeng Wei
Published: February 2022

Since the end of 2019, the Corona Virus Disease 2019 (COVID-19) pandemic has led to a surge in the use of all kinds of medical supplies, especially surgical masks. Based on the microstructure and anti-virus mechanism of melt-blown materials used for medical masks, this paper introduces the research status of nonwoven filter materials used for protective masks. At the same time, the surface interface structure of four disposable medical protective masks from different manufacturers was analyzed by scanning electron microscope, and the difference of melt-blown materials of these masks was studied. The results show that the fiber diameter of melt-blown mask with better protective effect is fine and compact, and the aperture formed between fibers is smaller. This reasearch provides new ideas for further research and development of non-woven materials for medical masks.
Effect of concrete viscosity on apparent quality of fair faced concrete
Authors: You Renliang , Zhang Pan , Qiu Yuetao , Zheng Qing
Published: February 2022

In this paper, concrete with different viscosity was prepared by adjusting the water binder ratio of concrete. The floating time of table tennis was used to characterize the viscosity of concrete, and the effect of concrete viscosity on the apparent quality of fair faced concrete was studied. The test results show that with the increase of concrete viscosity, the apparent porosity of concrete decreases first and then increases. When the water binder ratio is 0.37 and the floating time of table tennis is 40s, the appearance quality of concrete components is the best.
Microstructure characteristic of hot formed 22MnB5 steel and its relationship with delayed hydride cracking property
Authors: Wang Hua , Hao Shiyu , Wang Baolei , Kuang Chunfu
Published: February 2022

Hydrogen-induced delayed cracking is an important factor leading to the failure of ultra-high strength steels during service, thus in this study, the mechanical properties and hydrogen trapping of hot formed 22MnB5 steel considering different content of V (0, 0.05, 0.09 wt.%) and corresponding microstructure were investigated. Slow strain rate tensile tests (SSRT) were applied to obtain the tensile strength and elongation of samples under different medium conditions (air, HCl immersion and electrolytic hydrogen charging). Besides, microstructure and atomic distribution morphology of the samples were detected and analyzed by transmission electron microscope (TEM) and atomic probe tomography (APT) technique. Results showed that both resistances of hydrogen-induced delayed cracking in MnB-V5 and MnB-V9 samples were obviously better than that in MnB-V0 sample, besides, the delayed cracking resistances of MnB-V9 and MnB-V5 samples did not improve with the increase of V content, but basically remained the same. Lamellar residual austenite was found in all samples, but no hydrogen was grasped in the same area according to APT result. There was intragranular cementite in all samples, and it has grasped H in the same position. The carbides formed by V, Ti and other alloying elements were found in MnB-V5 and MnB-V9 and were considered to be an important factor in improving the anti-hydrogen delayed cracking performance of the steel.
Synthesis and performance study of a highly dispersed HPEG-type polycarboxylate superplasticizer
Authors: Lin Zeyu
Published: February 2022

HPEG has long been widely used as an alternative to TPEG. In this study, a new high-performance HPEG-type polycarboxylate superplasticizer PCE-A was synthesized by using H2O2 and sodium hypophosphite/Vc redox initiation system to provide free radicals under aqueous polymerization conditions with HPEG and acrylic acid as the main raw materials. The results showed that the best performance of the synthetic polycarboxylate superplasticizer was achieved when the acid to ether ratio was 4.50, Vc was 0.25%, H2O2 was 0.80% and sodium hypophosphite was 1.7%, which could effectively reduce the amount of admixture without affecting the working performance of concrete, and the concrete strength was higher.
Preparation Process and Quality Characterization of High Density Fine Grain Osmium Target for Coated Cathode
Authors: Ma Junda , Xia Yang , Xie Yuanfeng , Lv Hong , Zhang Chao
Published: February 2022

High quality osmium targets are the key influence in improving the emission performance, lifetime and reliability of M-type cathodes. In this experiment, oxidative distillation was used to prepare osmium powder with a purity greater than 99.99%. The effect of hydrogen sintering and hot pressing sintering processes on the densities and grain size of the targets was investigated. The results show that the oxidation distillation process can effectively separate Os from Si, Fe, Ni, Zn and other impurity elements, and the purity of osmium powder prepared by multiple oxidation distillation was not less than 99.99%. Both hydrogen sintering and hot pressing sintering processes can be used to obtain osmium targets with a density of not less than 95%. However, the sintering temperature and time used in the hot pressing sintering process under pressure assistance are significantly lower than those of hydrogen sintering, which is more conducive to inhibiting grain growth during the high densification sintering process. By optimizing the parameters of the hot pressing sintering process, the sintering temperature of 1500°C and the holding time of 1.5h resulted in an osmium target with a density of 99.11% and a grain size of ≤12. XPS analysis of the highly dense fine crystalline osmium targets prepared by hot pressing sintering showed that the C and O mass fractions on the surface of the targets were 0.85% and 4.43% respectively, and the C and O contents gradually decreased with increasing etching depth. The above highly dense and fine crystalline osmium targets can be used in the M-type cathode standard coating process to obtain high purity, dense and strong bonded osmium films.
Effect of shear thickening property of polymer on relative permeability
Authors: Zhang Wenlong , Hou Jian , Liu Yongge , Du Qingjun
Published: February 2022

The relative permeability at a high Darcy velocity was estimated by combining a numerical simulation model that considers the rheology of polymer in shear thickening region. After verifying the robustness of the method, the effect of shear thickening property of polymer on relative permeability was studied. The results show that when Darcy velocity exceeds 17.61 m/d, the apparent relative viscosity of polymer solution begins to increase, and the rheology of polymer changes from shear thinning to shear thickening behavior, which reduces water relative permeability. For water relative permeability model, as Darcy velocity increases, water relative permeability at residual oil decreases in a power function and exponent of water relative permeability model increases linearly.
Study on performance stability of Polycarboxylate Superplasticizer prepared at different temperatures
Authors: Zhong Lina , Wang Zhaopeng , Lin Zeyu , Fang Yunhui
Published: February 2022

The effects of initial dropping temperature, amount of ferrous sulfate and dropping time on the performance of Polycarboxylate Superplasticizer were studied, and the measures to maintain the performance stability of Polycarboxylate Superplasticizer from 15 °C to 40 °C were discussed. The results show that the stability of the process is better when the initial dropping temperature is 20°C-30°C. When the temperature is higher than 30 °C, the stability of the process can be achieved by prolonging the dropping time or reducing the amount of FeSO4; When the temperature is lower than 15 C, the performance can be improved by increasing the amount of FeSO4, so as to achieve the stability of the process.
Analysis on Influencing Factors and Control Measures of Metal Materials Heat Treatment Deformation
Authors: Yu Yanli
Published: February 2022

The scientific application of heat treatment technology is aimed at improving the performance of metal materials, which is very important for improving the utilization rate of metal materials. In the process of h meat treatment, metals are easily affected by factors and deform, which leads to theetal materials can’t be used normally. Therefore, it is necessary to deeply analyze the factors affecting heat treatment, and then formulate effective control measures to reduce the probability of metal material deformation and improve the service performance of metal materials. Based on this, this paper explores the influencing factors and control measures of heat treatment deformation of metal materials.
Study on Illumination Measurement Method of Lighting Environment Based on RBF Neural Network
Authors: Zhang Yujie , Li Si
Published: February 2022

In order to better measure the indoor light environment, evaluate the quality of the indoor lighting environment, and improve the requirements of lighting comfort, a camera image measurement illuminance method based on RBF(Radial basis function)neural network is proposed, and the camera sensor imaging theory is derived and analyzed to obtain the environmental illuminance and camera sensor The relationship between the parameters, the establishment of the RBF neural network model, by building an experimental system platform, collecting data sets to train the network model, fitting the neural network model parameters to obtain the illuminance measurement model, and use the image gray level and the reference point illuminance as the neural network Input and ambient illuminance as output. The prediction result shows that the error between the illuminance value predicted by the neural network and the actual measured value of the illuminance meter is within 10lx, and the relative error is less than 8%, which meets the requirements of lighting building design standards. Therefore, this method can achieve rapid measurement of the illuminance in the environment, and has a relatively high High precision.
The Design of Low-concentration Dust Detection System Based on Mie Scattering Theory
Authors: Zhang Zhaopeng
Published: February 2022

According to the requirement of low-concentration dust emission in China, this paper designed a low-cost and high-precision dust detection system based on Mie scattering. Through theoretical analysis, the relationship between the intensity of scattered light and the concentration of soot is obtained. The laser emitting unit, signal receiving unit and STM32 data processing unit are designed. The driving principle of laser modulation and the principle of selective signal amplification of weak signal are analyzed. The host computer program is written with LabVIEW software, and the test data are displayed on the front panel of the host computer. The experimental results show that this system has high sensitivity, fast response, good repeatability, and can be measured online for a long time, which means this system has good practicability.
Research on the Method of Measuring Soil Water Content by Time Domain Reflectometry
Authors: Cui Jiawei , Kong Saibo
Published: February 2022

Time domain reflectometry (TDR) can calculate the water content by testing the dielectric constant of the rock and soil medium, but the TDR measurement results under time domain conditions are susceptible to the influence of soil conductivity. This article introduces the basic theory of TDR measurement, then uses the transmission scattering matrix to describe the transmission equation, analyzes the dielectric constant in the frequency domain, simulates the TDR waveform with matlab based on the Debye model, and fits the simulated waveform to the measured waveform, and then according to the simulated waveform The matching degree proves the feasibility of calibrating the dielectric constant of the soil. Taking clay as the measurement object, finally fitting a simulation waveform with a higher degree of matching with the measurement waveform, which proves the feasibility of the method and has certain reference value for the study of the TDR method of measuring soil dielectric constant and water content.
Analysis on harmonic characteristic of transformer DC bias caused by metro stray current
Authors: Cheng Xinxiang , Ni Yanru , Yu Kun , Zeng Xiangjun , Zhuo Chao , Han Wei
Published: February 2022

With the continuous improvement of the economic level, urban rail transit has been vigorously developed. However, the metro stray current will be generated during the actual operation of urban rail, which will cause transformer DC bias along the metro line. In order to effectively evaluate the influence of the transformer on the DC bias under urban rail operation, the stray current distribution model with single and double-ended power supply mode was established, and the numerical calculation of the stray current was realized. Based on the real-time dynamic change characteristics of the stray current, a synchronous simulation model of the transformer DC bias was established, and the harmonic characteristics of the transformer excitation current were further analyzed. The simulation test shows that when the direct current is injected into the neutral point of the transformer, the excitation current waveform is asymmetrical along the positive and negative semi-axes, and the odd and even harmonics coexist. And the influence of transformer DC bias is weakened when transformer air core reactance is increased. The characteristic quantities such as excitation current amplitude, waveform characteristics, and harmonic content have been quantitatively analyzed in this paper, which has certain guiding significance for evaluating the influence of transformer DC bias.
Research on Ultrasonic Quantitative Evaluation Technology of Complex Defects Based on Neural Network
Authors: Li Xinglong , Liu Shengguo , Cheng Shuo , Lin Jindi , Liu Rongchun , Wang Leyu , Zhou Zhilin
Published: February 2022

As one of the five non-destructive testing methods, ultrasonic testing is widely used because of its accurate positioning, high sensitivity and simple operation, but the method is still difficult to locate and quantify complex shape defects. The large amount of data required for ultrasonic imaging leads to low detection efficiency. Based on this, the article establishes an inversion system for evaluating complex shape defects, which includes ultrasonic A-scan technology, BP neural network, image processing technology and signal processing technology. The system is verified by simulation and experiment. The results of the defect inversion are as follows: the similarity coefficients are all greater than 0.89, the maximum value can reach 0.95; the area error is less than 11%, the minimum value can reach 1.2%; the centroid x error is less than 12%, the minimum value can reach 1.58%; the centroid y error is less than 11%, the minimum value can reach 2.15%. The result of defect inversion further verifies the accuracy and reliability of the complex defect inversion system.
Sharing VSG Operation with Synchronous Generator
Authors: Hasabelrasul Hashim , Cai Zhenjiang , Sun Lei , Suo Xuesong
Published: February 2022

While several synchronous generators (SGs) are substituted through virtual synchronous generators (VSGs), some SGs remain in today’s microgrids. And the majority of the research assumes that VSG mimics SG characteristics, allowing it to function in parallel among SGs. However, few studies have gone to great lengths to study this concept. As a result, the paper’s goal system is a microgrid that runs both VSG and regular SG in parallel. In this article, new parameters for the VSG are designed in parallel with the SG. Then, in an independent microgrid, identical VSG-VSG and scenario SG-VSG configurations are fixed to equate the complex activity. The emotional responses contrasted when the load requirement is shared fairly and proportionally.
An integrated method of system maintainability, testability and supportability design and evaluation
Authors: Zhang Huazhao , Liu Baoding , Yu Jinsong , Liang Guozhu
Published: February 2022

General quality characteristics of equipment system have a guiding role for the design, production and use of equipment and are vital for the evaluation of these characteristics. They are important indicators to measure whether the equipment meets the established standard. Aiming at the problem that the design and evaluation process of equipment general quality characteristics are independent and unrelated, this paper proposes an integrated and continuous maintainability, testability and supportability design and evaluation process based on FMECA and MSFG, and designs corresponding evaluation parameters. An impact-based fault mode rating method is also proposed to better evaluate the general quality characteristics of equipment.
Research on Real-time Simulation of Power Electronic Circuits Based on Simscape
Authors: Xu Baohe , Lu Li , Gong Dawei
Published: February 2022

In order to realize hardware-in-the-loop simulation of commonly used power electronic circuits, a method of joint simulation using Simcape and field programmable gate array (FPGA) is proposed. This article adopts a switch modeling method suitable for high-frequency characteristics, namely the switch function method. It effectively solves the problem of rigidity non-convergence in the modeling of the binary resistance method, as well as the transient error caused by the binary LC method when the system state is switched with the increase of the switching frequency, which reduces the simulation accuracy. Taking the single-phase full-bridge inverter circuit as an example, a Simscape model based on the state-space averaging method was established, and the HDL code was automatically generated using the Simscape HDL Workflow Advisor tool, and the hardware-in-the-loop simulation was completed with FPGA. Finally, the simulation results with Simulink comparison verify the effectiveness and feasibility of the method.
Intelligent control of flexible joint based on cooperative learning theory
Authors: Shi Qun , Jia Xiangjie
Published: February 2022

It is complex and time-consuming for obtaining accurate dynamics of industrial robots. The flexibility of the joint not only increases the adverse effects of nonlinear factors, but also makes the controller design of robot significantly difficult. In order to improve the performance of robots containing joint flexibility, cooperative learning (COL) theory is proposed in this paper. Based on this theory, a model-free intelligent controller is trained and successfully applied to the flexible joints. Compared with the conventional PID controller and RBF controller, the cumulative tracking error produced by the cooperative learning intelligent controller is reduced by 38.25% and 31.08%, respectively, and the robustness is improved in the trajectory tracking experiment and the robustness experiment. The experimental results demonstrate the feasibility and effectiveness of the cooperative learning theory.
Influence of Public Mobile Communication System on the Frequency of S-Band Radars
Authors: Yang Jian , Chang Zengtian , Su Dongchu , Li Chenyong , Luo Siwei , Chang BoWei , Qiang Lu
Published: February 2022

Given the interference between public mobile communication system and S-band radars, an applicable interference analysis model was established, the typical frequency parameters of radar and the key parameters of the base station were sorted out, the radiation parameters of the mobile terminal (MT) were tested practically, and the interferences of the base station and MT to radar were calculated. Further, the Monte Carlo method was taken to simulate the system-level lumped interference of the communication system to radar, and an analysis was made on the influence of the communication system on the frequency of radar. The results revealed that the public mobile communication system had severe lumped interference with radar, which may affect radar frequency. Therefore, it is necessary to take measures to protect radar.
Lightweight IT Operation and Maintenance Integrated Monitoring Method for APP System
Authors: Wang Xuyong , Chen Rui
Published: February 2022

Through the operation and maintenance system, the centralized control of the operation state of enterprise equipment can be realized. In order to solve the problem of unstable monitoring effect of traditional methods, untimely risk early warning and high error rate of early warning information, a lightweight it operation and maintenance integrated monitoring method for APP system is proposed. Analyze the actual needs of the monitoring function of the lightweight IT operation and maintenance system, design a targeted IT operation and maintenance monitoring function module according to the analysis results, and give the lightweight IT operation and maintenance process. A lightweight IT operation and maintenance database is established based on fuzzy theory, and data with similar characteristics is simulated to minimize the dispersion of sample data. Finally, in order to achieve integrated monitoring of lightweight IT operation and maintenance, and to improve monitoring efficiency and monitoring accuracy, it is necessary to reduce the dimensionality of multi-dimensional data, which is mainly achieved through principal component analysis. The experimental results show that compared with the traditional method, the method in this paper can obtain accurate early warning information in time in monitoring, indicating that its monitoring effect is better, and it has a certain positive effect on ensuring the safe operation of the IT operation and maintenance system.
IBM Small-Scale Superconducting Quantum Computer Not Gate Error Test
Authors: He Ming , Liu Xiaonan , Wang Junchao , An Jiale
Published: February 2022

Quantum NOT gates play an important role in the process of quantum information conversion. However, when the X-gate operation is executed on a real quantum computer, there is a large deviation between the actual operation result and the theory, which will lead to inaccurate results when the quantum algorithm containing the X-gate operation is executed. In order to facilitate users to understand the error fluctuations of the X gate in time before executing the quantum algorithm containing the X gate operation on the IBM quantum cloud platform, this paper proposes a method to measure the X gate error. By measuring the X-gate error of four small-scale superconducting quantum computers on the back end of the IBM quantum cloud platform, analyze the degree of fluctuation of the actual measurement value of the quantum device; at the same time, under different execution times shots, the influence of the X-gate test is analyzed. The test results show that the measured value of each qubit of different quantum devices fluctuates to different degrees; the execution times of shots are different, and the test results of X-gate error will be affected to different degrees. This test method helps users select the optimal performance of the qubits before executing quantum algorithms with X gate on IBM's small-scale quantum computers.
Object detection based on Yolov4-Tiny and Improved Bidirectional feature pyramid network
Authors: Liu Qi , Fan Xiaoyu , Xi Zhipeng , Yin Zhijian , Yang Zhen
Published: February 2022

In the field of small object detection, Yolov4-Tiny is inadequate in feature extraction and does not make best of multi-scale features. In this paper, an improved BiFPN framework is proposed based on Yolov4-Tiny to increase object detection precision. Moreover, the Yolov4-Tiny is taken as the backbone network and introduce spatial pyramid pooling (SPP) to connect and merge multi-scale regions. Finally, our method can achieve 79.53% map on Pascal VOC dataset, which is 2.12% higher than the original Yolov4-Tiny model.
Finding Discriminative Regions with More Subtle Granularities for Fine-grained Image Classification
Authors: Liu Qi , Xi Zhipeng , Fan Xiaoyu , Yin Zhijian , Yang Zhen
Published: February 2022

Classifying subcategories of the same category (such as birds, cars, airplanes) is mainly to find discriminative features and accuracy regional positions in the fine-grained visual classification (FGVC). In this article, we propose to use global average pooling slice feature maps to find significant discriminative regions without complicated network designs or training operations and use Drop-Block mechanisms to solve the problem of network overfitting. Specially, we use the feature maps of the multi-branches as inputs, and average-pooling them with different sizes of convolution kernels to obtain feature maps that containing deeper and shallow information for getting more accuracy granularities. Our methods are called as More Accurate Multi-Granular Convolutional Neural Network (MAG-CNN). Compared with other networks with more complex designs, the network only requires common operations such as pooling and convolution to achieve higher accuracy. The MAG-CNN can be trained end-to-end, without any bounding-box, and our method has reached the most advanced performance on three common fine-grained image classification benchmark datasets (CUB-Birds, FGVC-Aircraft, and Stanford-Cars).
Dynamic Analysis of the influence of the Rotor Centroid Offset of Gyrowheel
Authors: Liu Xiaokun , Yang Guanglie , Mo Chaoming , Tan Minglang , Gu Dongqing , Song Bin , Wu Shufan
Published: February 2022

Gyrowheel is a new electromechanical servo device which can realize the integration of spacecraft attitude control and attitude measurement. Due to the existence of machining and assembly errors, there must be a deviation between the rotor centroid of the gyrowheel and the support center, that is, the centroid offset. Firstly, to solve this problem, the dynamic modeling of rotor center of mass offset is carried out from the perspective of vector mechanics by using D'Alembert principle. Secondly, the established dynamic model is simplified, and the influence of rotor center of mass offset on the micro vibration of gyrowheel is analyzed. Finally, the correctness of this method is verified by simulation.
Improvement and Research of Collaborative Filtering Algorithm Based on Penalty Factor
Authors: Li Panying , Han Yuxuan , Wen Xiumei , Meng Fanxing
Published: February 2022

The rapid development of the Internet has pushed society into the era of information explosion, and people are faced with more and more information screening and choices. A recommendation system is an effective way to process massive amounts of information, and it is also a tool that can make recommendations based on user behavior. Traditional collaborative filtering algorithms generally use the cosine similarity formula to calculate the similarity between users or items to make recommendations. Due to the popularity of the Internet, more and more popular items have appeared. The appearance of popular items not only affects the recommendation results, but also fails to reflect the real needs of users. This paper proposes an improved formula for cosine similarity with a penalty factor, which can restrain the influence of popular items on the recommendation result. Finally, the Movie Lens data set is used to verify that the recommended performance indicators have been improved to a certain extent.
Overview of Energy Consumption Optimization in Mobile Edge Computing
Authors: Hu Bingyi , Gao Jixun , Hu Yanxin , Wang Huaichen , Liu Jialei
Published: February 2022

The energy consumption of traditional mobile network is mainly reflected by task calculation and data transmission. The edge server in mobile edge computing is placed at the edge of the network closer to the mobile terminal device. When the computing resources of the mobile terminal device are insufficient, the task can be offloaded to the edge server for processing. This paper discusses the energy consumption optimization in the Mobile Edge Computing (MEC) system, which is composed of the edge server and mobile devices at the edge of the network. Firstly, the system model of MEC is elaborated. Secondly, the energy consumption optimization for mobile devices and base stations is studied. Which oriented to the mobile device energy consumption optimization is divided into multiple users - single MEC server scenarios of energy consumption optimization and multiple users - the energy optimization of MEC server scenario, and enumerate the oriented to the base station and a new method for the optimization of energy consumption for mobile equipment energy consumption optimization method, in addition to the insufficiencies of these methods and the prospect of the future are also explained.
The Improved Quantum Secret Sharing Protocol Based on Grover Algorithm
Authors: Yu Zhuo
Published: February 2022

Quantum secret sharing(QSS) is a cryptographic protocol based on the uncertainty principle and quantum no-cloning theorem and is an essential aspect in quantum computing. This paper describes the Grover search algorithm and how to improve QSS protocol by Grover Algorithm. The QSS based on the Grover algorithm is more secure and easier to operate compared to old QSS protocols. Some scientists improved the security of the first QSS protocol based on QSA by changing the check mode. After that, a protocol with quite different procedures was proposed. The improved one enhances the feasibility of the protocol and it could also make sure that the communication is secure from the attacks.
Ecological resilience: what to measure and how
Authors: Dakos Vasilis , Kéfi Sonia
Published: February 2022

The question of what and how to measure ecological resilience has been troubling ecologists since Holling 1973s seminal paper in which he defined resilience as the ability of a system to withstand perturbations without shifting to a different state. This definition moved the focus from studying the local stability of a single attractor to which a system always converges, to the idea that a system may converge to different states when perturbed. These two concepts have later on led to the definitions of engineering (local stability) vs ecological (non-local stability) resilience metrics. While engineering resilience is associated to clear metrics, measuring ecological resilience has remained elusive. As a result, the two notions have been studied largely independently from one another and although several attempts have been devoted to mapping them together in some kind of a coherent framework, the extent to which they overlap or complement each other in quantifying the resilience of a system is not yet fully understood. In this perspective, we focus on metrics that quantify resilience following Holling’s definition based on the concept of the stability landscape. We explore the relationships between different engineering and ecological resilience metrics derived from bistable systems and show that, for low dimensional ecological models, the correlation between engineering and ecological resilience can be high. We also review current approaches for measuring resilience from models and data, and we outline challenges which, if answered, could help us make progress toward a more reliable quantification of resilience in practice.