bluuebunny/crossref_metadata_2025 huggingface dataset:
Predict alone, decide together: cardiac abnormality detection based on single lead classifier voting
Authors: Aublin Pierre G , Ben Ammar Mouin , Fix Jeremy , Barret Michel , Behar Joachim A , Oster Julien
Published: April 2022

Objective. A classifier based on weighted voting of multiple single-lead based models combining deep learning (DL) representation and hand-crafted features was developed to classify 26 cardiac abnormalities from different lead subsets of short-term electrocardiograms (ECG). Approach. A two-stage method was proposed for the multilead prediction. First a lead-agnostic hybrid classifier was trained to predict the pathologies from single-lead ECG signals. The classifier combined fully automated DL features extracted through a convolutional neural network with hand-crafted features through a fully connected layer. Second, a voting of the single-lead based predictions was performed. For the 12-lead subset, voting consisted in an optimised weighting of the output probabilities of all available single lead predictions. For other lead subsets, voting simply consisted in the average of the lead predictions. Main results. This approach achieved a challenge test score of 0.48, 0.47, 0.46, 0.46, 0.45 on the 12, 6, 4, 3, 2-lead subsets respectively on the 2021 Physionet/Computing in Cardiology challenge hidden test set. The use of an hybrid approach and more advanced voting layer improved some individual class classification but did not offer better generalization than our baseline fully DL approach. Significance. The proposed approach showed potential at correctly classifying main cardiac abnormalities and dealt well with reduced lead subsets.
Towards a fusion power plant: integration of physics and technology
Authors: Morris A W , Akers R J , Cox M , Militello F , Surrey E , Waldon C W , Wilson H R , Zohm H
Published: April 2022

A fusion power plant can only exist with physics and technology acting in synchrony, over space (angstroms to tens of metres) and time (femtoseconds to decades). Recent experience with the European DEMO programme has shown how important it is to start integration early, yet go deep enough to uncover the integration impact, favourable and unfavourable, of the detailed physical and technological characteristics. There are some initially surprising interactions, for example, the fusion power density links the properties of materials in the components to the approaches to waste and remote maintenance in the context of a rigorous safety and environment regime. In this brief tour of a power plant based on a tokamak we outline the major interfaces between plasma physics and technology and engineering considering examples from the European DEMO (exhaust power handling, tritium management and plasma scenarios) with an eye on other concepts. We see how attempting integrated solutions can lead to discoveries and ways to ease interfaces despite the deep coupling of the many aspects of a tokamak plant. A power plant’s plasma, materials and components will be in new parameter spaces with new mechanisms and combinations; the design will therefore be based to a significant extent on sophisticated physics and engineering models making substantial extrapolations. There are however gaps in understanding as well as data—together these are termed ‘uncertainties’. Early integration in depth therefore represents a conceptual, intellectual and practical challenge, a challenge sharpened by the time pressure imposed by the global need for low carbon energy supplies such as fusion. There is an opportunity (and need) to use emerging transformational advances in computational algorithms and hardware to integrate and advance, despite the ‘uncertainties’ and limited experimental data. We use examples to explore how an integrated approach has the potential to lead to consistent designs that could also be resilient to the residual uncertainties. The paper may stimulate some new thinking as fusion moves to the design of complete power plants alongside an evolving and maturing research programme.
Plasma power balance: methodology and investigations of microwave capillary discharges
Authors: Coquery F , Leroy O , Minea T , Stancu G D
Published: April 2022

Nowadays, where strong energy constraints are set by the environmental and economical context, the real power coupled in plasmas becomes a critical aspect particularly for applications where plasma technologies are facing competition. This issue is enhanced for atmospheric pressures micro-plasmas, where the local power density can be very high (e.g. 105 W cm−3) which implies fast heat exchanges. The precise knowledge of the power coupled to plasma is also a key for fundamental understanding of discharge properties. This is often used as an input parameter for plasma modeling and its inaccuracy can mitigate the predictive quality of plasma simulation tools. In the present paper the macroscopic power balance was established for continuous microwave (MW) plasmas generated in capillaries in argon gas flows. The macroscopic power budgets were performed based on measurements of microwave leak fluxes, heat fluxes (thermal radiation, convection, conduction), optical radiation and chemical powers. It was proven that the traditional power measurements at the MW generator would largely overestimate the real power coupled to plasmas, namely by at least a factor two. An important power fraction is found in the heat transfer through the MW launcher, the impedance mismatching being here better assessed. The proposed methodology, which is based on the physics of transport phenomena, can be employed for characterization of other (micro-) plasma sources.
The muon Smasher’s guide
Authors: Al Ali Hind , Arkani-Hamed Nima , Banta Ian , Benevedes Sean , Buttazzo Dario , Cai Tianji , Cheng Junyi , Cohen Timothy , Craig Nathaniel , Ekhterachian Majid , Fan JiJi , Forslund Matthew , Garcia Isabel Garcia , Homiller Samuel , Koren Seth , Koszegi Giacomo , Liu Zhen , Lu Qianshu , Lyu Kun-Feng , Mariotti Alberto , McCune Amara , Meade Patrick , Ojalvo Isobel , Oktem Umut , Redigolo Diego , Reece Matthew , Sala Filippo , Sundrum Raman , Sutherland Dave , Tesi Andrea , Trott Timothy , Tully Chris , Wang Lian-Tao , Wang Menghang
Published: April 2022

We lay out a comprehensive physics case for a future high-energy muon collider, exploring a range of collision energies (from 1 to 100 TeV) and luminosities. We highlight the advantages of such a collider over proposed alternatives. We show how one can leverage both the point-like nature of the muons themselves as well as the cloud of electroweak radiation that surrounds the beam to blur the dichotomy between energy and precision in the search for new physics. The physics case is buttressed by a range of studies with applications to electroweak symmetry breaking, dark matter, and the naturalness of the weak scale. Furthermore, we make sharp connections with complementary experiments that are probing new physics effects using electric dipole moments, flavor violation, and gravitational waves. An extensive appendix provides cross section predictions as a function of the center-of-mass energy for many canonical simplified models.
Influence of fabrication parameters on the magnetic and structural properties of Mn5Ge3
Authors: Xie Yufang , Li Zichao , Begeza Viktor , Funk Hannes Simon , Fischer Inga Anita , Zeng Yu-Jia , Helm Manfred , Zhou Shengqiang , Prucnal Slawomir
Published: April 2022

Mn5Ge3 is a ferromagnetic material with the high potential for spintronic applications. Usually, it is grown by conventional solid state reaction of manganese with germanium using molecular beam epitaxy. Here, we report the structural and magnetic properties of Mn5Ge3 layers grown on Ge substrates using ultrafast-solid phase epitaxy (SPE) method. We investigate the influence of the substrate orientation, Mn layer thickness and annealing parameters on the crystallographic orientation and magnetization of Mn5Ge3. It is shown that after millisecond range SPE, Mn5Ge3 films always have a preferred (100) orientation whether grown on Ge (001) or (111) substrates, which determines the orientation of the magnetization easy axis lying in the film plane along c axis independent of the layer thickness. The Curie temperature of Mn5Ge3 weakly depends on fabrication parameters.
Single event burnout sensitivity of SiC and Si
Authors: Littlefair Matthew T M , Simdyankin Sergei , Turvey Simon , Groves Chris , Horsfall Alton B
Published: April 2022

Exposure to ionizing radiation has the potential to catastrophically modify the operation, and destroy, electronic components in microseconds. The electrification of aircraft necessitates the need to use the most power dense and lowest loss semiconductor devices available, and the increasing supply voltages results in extremely high electric fields within the devices. These conditions create the worst case environment for the Single Event Effect (SEE), the instantaneous alteration in device response after high energy particle interaction, with a destructive form of SEE, the single event burnout (SEB), resulting in total failure of the device with potentially explosive consequences. To enable circuits to operate with these high supply voltages, SiC is rapidly becoming the semiconductor of choice. However, the radiation response of SiC power devices during operation is unknown. Here we show that SiC offers a 60% reduction in cosmic ray sensitivity in comparison to Si devices with an equivalent voltage rating. The data show that Si fails when subjected to a heavy ion impact with Linear Energy Transfer (LET) equivalent to 0.2% of the silver ions commonly used for SEE testing. In total contrast, we show that SiC does not exhibit failure during exposure to any heavy ion LET up to values three times greater than those commonly used in testing at any bias up to 99% of the breakdown voltage. The data show that SiC is a robust material and therefore has the potential to replace Si as the material of choice for high reliability avionic applications, as it far exceeds the performance of Si in cosmic ray environments, facilitating significant advances in the electrification of aircraft to be made in the near future.
The benefits of CMB delensing
Authors: Hotinli Selim C. , Meyers Joel , Trendafilova Cynthia , Green Daniel , van Engelen Alexander
Published: April 2022

The effects of gravitational lensing of the cosmic microwave
background (CMB) have been measured at high significance with
existing data and will be measured even more precisely in future
surveys. Reversing the effects of lensing on the observed CMB
temperature and polarization maps provides a variety of benefits.
Delensed CMB spectra have sharper acoustic peaks and more prominent
damping tails, allowing for improved inferences of cosmological
parameters that impact those features. Delensing reduces B-mode
power, aiding the search for primordial gravitational waves and
allowing for lower variance reconstruction of lensing and other
sources of secondary CMB anisotropies. Lensing-induced power
spectrum covariances are reduced by delensing, simplifying analyses
and improving constraints on primordial non-Gaussianities. Biases
that result from incorrectly modeling nonlinear and baryonic
feedback effects on the lensing power spectrum are mitigated by
delensing. All of these benefits are possible without any changes
to experimental or survey design. We develop a self-consistent,
iterative, all-orders treatment of CMB delensing on the curved sky
and demonstrate the impact that delensing will have with future
surveys.
The Potential of Detecting Radio-flaring Ultracool Dwarfs at L band in the FAST Drift-scan Survey
Authors: Tang Jing , Tsai Chao-Wei , Li Di
Published: April 2022

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) completed its commissioning and began the Commensal Radio Astronomy FasT Survey (CRAFTS), a multi-year survey to cover 60% of the sky, in 2020. We present predictions for the number of radio-flaring ultracool dwarfs (UCDs) that are likely to be detected by CRAFTS. Based on the observed flaring UCDs from a number of unbiased, targeted radio surveys in the literature, we derive a detection rate of ≥3%. Assuming a flat radio spectrum ν
L

ν
∝ ν

β+1 with β = −1.0 for UCD flares, we construct a flare luminosity function

dN

/

dL
∝

L

−
1.96
±
0.45

(here L = ν
L

ν
). CRAFTS is found to be sensitive enough for flares from UCDs up to ∼180 pc. Considering the Galactic thin disk, we carry out a 3D Monte Carlo simulation of the UCD population, which is then fed to mock CRAFTS observations. We estimate that ∼170 flaring UCDs would be detected through transient searches in circular polarization. Though only marginally sensitive to the scale height of UCDs, the results are very sensitive to the assumed spectral index β. For β from 0 to −2.5, the number of expected detections increases dramatically from ∼20 to ∼3460. We also contemplate the strategies for following up candidates of flaring UCDs, and discuss the implications of survey results for improving our knowledge of UCD behavior at L band and dynamos.
Global saturation physics of ion temperature gradient turbulence in finite normalized pressure tokamaks
Authors: Masui H. , Ishizawa A. , Imadera K. , Kishimoto Y. , Nakamura Y.
Published: April 2022

Nonlinear saturation mechanism of ion-temperature-gradient turbulence at finite normalized pressure is identified by analysis of the nonlinear entropy transfer in global gyrokinetic simulations of the turbulence. Turbulence at such finite normalized pressure is electromagnetic and often exhibits non-saturation due to a lack of zonal flows by the influence of magnetic fluctuations of the turbulence in local gyrokinetic simulations. The present study identifies a new saturation mechanism caused by global entropy transfer due to turbulent E × B flow convection in real space. The convection of the entropy associated with the turbulence in the radial direction produces global zonal flows at the both sides of the most active region of the turbulence to avoid the effect of the magnetic fluctuations, and then global zonal-flow excitation is not suppressed, leading to a steady state of the turbulence.
Gyrokinetic modeling of anisotropic energetic particle driven instabilities in tokamak plasmas
Authors: Rettino B. , Hayward-Schneider T. , Biancalani A. , Bottino A. , Lauber Ph. , Chavdarovski I. , Weiland M. , Vannini F. , Jenko F.
Published: April 2022

Energetic particles produced by neutral beams are observed to excite energetic-particle-driven geodesic acoustic modes in tokamaks. We study the effects of anisotropy of distribution function of the energetic particles on the excitation of such instabilities with ORB5, a gyrokinetic particle-in-cell code. Numerical results are shown for linear electrostatic simulations with ORB5. The growth rate is found to be sensitively dependent on the phase-space shape of the distribution function. The behavior of the instability is qualitatively compared to the theoretical analysis of dispersion relations. Realistic neutral beam energetic particle anisotropic distributions are obtained from the heating solver RABBIT and are introduced into ORB5 as input distribution function. Results show a dependence of the growth rate on the injection angle. A qualitative comparison between the numerical results and experimental measurements is presented. An explanation for the differences is advanced.
Conceptual design and optimization of an ITER-type ICRF antenna on CFETR
Authors: Zhang W. , Liang Q.C. , Qin C.M. , Zhang X.J. , Wang Y.S. , Yang H. , Liu L.N. , Zhu G.H. , Mao Y.Z. , Yuan S. , Cheng Y.
Published: April 2022

The Chinese Fusion Engineering Testing Reactor (CFETR) plans to use an ITER-type antenna and couple ∼30 MW ion cyclotron range of frequencies (ICRF) power to the plasma. In this paper, the physical design of a CFETR antenna in the midplane port is carried out. Parameter scans were performed to study the optimized toroidal and poloidal numbers of straps as well as the optimized geometric sizes of the straps. The coupling resistance, power spectrum, maximum voltage in the resonant transmission line of the strap and parallel electric field in the antenna vicinity are used to determine the performance of the studied antennas. It is shown that four poloidal substraps (i.e. quadruplets) and six toroidal strap columns arranged in half of the antenna allows the antenna to have the best coupling capability. To improve the coupling capability of the proposed antenna model, local gas puffing methods, as well as various antenna phasings, are studied. It is indicated that the coupling resistance can be increased by a factor of three for all studied antenna phasings when applying the midplane gas puffing with a gas puff rate in the order of 4 × 1023 el s-1. The toroidal phasings suitable for heating include (0, pi, 0, pi, 0, pi) and (0, pi, pi, 0, 0, pi).
Divertorlets concept for low-recycling fusion reactor divertor: experimental, analytical and numerical verification
Authors: Saenz F. , Sun Z. , Fisher A.E. , Wynne B. , Kolemen E.
Published: April 2022

The ‘divertorlets’ concept is a potential non-evaporative liquid metal solution for heat removal at low recycling regime. A toroidal divertorlets  prototype was built and tested in LMX-U at Princeton Plasma Physics Laboratory to evaluate the performance of this configuration. In this paper, details of the design, experimental results, comparison with analytical theory and MHD numerical simulations of toroidal divertorlets are covered. Experiments, analytical model and simulations showed agreement and allowed the projection of operation properties at higher magnetic flux densities (reactor-like operation), proving the concept to be a compelling solution for divertor applications.
A lightweight convolutional network for infrared object detection and tracking
Authors: Xu Yin , Fan Qiang
Published: April 2022

As an important application of computer vision, visual tracking has being a fundamental topic. Compared with visible image, infrared image has the characteristic of low resolution, blurred contour and single color feature. Thus, it is still a challenge for infrared object tracking. Further, it is difficult to balance the real-time performance and accuracy. This paper proposed a method for target detection and tracking, with a deeper and lightweight MobileNet V2 structure as the backbone network. In the end, the tracker is tested on various datasets. Result shows that the tracker can get a balance between tracking accuracy and inference speed, which is crucial for deployment on mobile devices.
Towards efficient quantized inference for convolutional neural network on edge system
Authors: Tan Hai , Wang Nan , Lei Bo
Published: April 2022

Convolutional Neural Networks (CNN) have made splendid achievements in various object detection tasks. To extend the applications of CNN detection models, the implementation of model inference on edge platforms, such as ASIC, FPGA and other embedded systems, has been intensively investigated in recent years. However, the huge model size and its enormous overhead constrain the deployment of detection model on edge platform which always has limited computational capability. Quantized inference of CNN model is one of the efficient approach to running model on edge platform. In this paper, we develop a hardware-friendly quantized inference scheme of detection model that is used for efficient inference on embedded FPGA systems. The proposed method contains several techniques that are able to optimize the quantized inference of detection model on FPGA device. The experimental results demonstrate that not only make the detection model quantized inference more efficient but also maintain the accuracy of object detection.
A deep learning approach for direction of arrival estimation using automotive-grade ultrasonic sensors
Authors: Elamir Mohamed Shawki , Gotzig Heinrich , Zöllner Raoul , Mäder Patrick
Published: April 2022

In this paper, a deep learning approach is presented for direction of arrival estimation using automotive-grade ultrasonic sensors which are used for driving assistance systems such as automatic parking. A study and implementation of the state of the art deterministic direction of arrival estimation algorithms is used as a benchmark for the performance of the proposed approach. Analysis of the performance of the proposed algorithms against the existing algorithms is carried out over simulation data as well as data from a measurement campaign done using automotive-grade ultrasonic sensors. Both sets of results clearly show the superiority of the proposed approach under realistic conditions such as noise from the environment as well as eventual errors in measurements. It is demonstrated as well how the proposed approach can overcome some of the known limitations of the existing algorithms such as precision dilution of triangulation and aliasing.
Application and Research of Elevator Internet of Things-Lifting Robot Using Elevator Scheme
Authors: Zhang Pengzhao , Chen Hu , Lv Qin , Shen XiaYang
Published: April 2022

To satisfy the demand of the handing robot using elevator in automatic workshop, we had finished the communication between the control system RCS of the elevator and the handling robot based on Modbus TCP protocol, so as to realize the interaction between the control robot and the Elevator Internet of Things system. The research of this paper provides a solution for the access and application of the handling robot in the Elevator Internet of Things, which solves the problem of the handling robot in the elevator up and down, and provides a new way for the material transportation efficiently in the three-dimensional industrial plant.
Multi-material 3D-Printing Soft Robot Functional Component
Authors: Ma Kaiqi , Zhang Yin , Jin Guoqing
Published: April 2022

—3D printing has a wide range of applications and addresses many challenges inherited from conventional manufacturing techniques. This paper presents a dual-extrusion 3D printing platform capable of printing soft materials for soft robot functional components. Dow Corning-737 and Dragon Skin-0030 materials are used. Single-line experiment is used to determine the optimization parameters of extrusion pressure, printing speed, and layer thickness of the developed multi-material 3D printing platform. A soft valve consisting of two soft materials has been fabricated, and the printed soft valve is verified by a performance experiment. The results indicate that the developed 3D printing platform can fabricate soft robot functional components at high speed with high accuracy.
A potential fault of circuit breaker found using SF6 decomposition products detection
Authors: Fu Lijun , Guan Yanling , Zhang Liang , Zhang Dewen , Wang Han , Chi Jingyuan , Wei Bing
Published: April 2022

A 126kV circuit breaker was found to have latent fault by SF6 decomposition product detection method. It was found that the sulfur hexafluoride gas decomposition products of the circuit breaker contained a large amount of CO gas, a certain amount of SO2 and H2S, and a small amount of HF gas. The characteristic components and their contents of the decomposition products were analyzed, it is preliminarily concluded that there is insulation material fault in the circuit breaker, and the potential fault is further confirmed by the disassembly inspection that the MoS2 lithium base grease is overcoated at the metal tie rod joint.
Design and Implementation of WSN-based Warehouse Temperature Sensor Monitoring System
Authors: Wang Qijian , Xia Mengqin , Chen Yehui , Yu Yuting
Published: April 2022

China is a large agricultural country. As an important part of the national economic foundation, the scientific storage of grain is particularly important in the process of grain production. This system uses STC89C52, nRF24L01, DHT11, etc. to form a WSN-based wireless temperature and humidity sensor monitoring system. The system monitors the humidity and temperature in the granary in real time. If the set point is exceeded, it will give an alarm. The timeliness and accuracy of environmental monitoring data on granary management will be improved, and human resources will be saved.
Simulation Analysis and Fabrication of a Silicon Carbide-Based Piezoresistive Accelerometer
Authors: Zhai Yanxin , Li Haiwang , Tao Zhi , Yang Chunhui , Cao Xiaoda , Che Zhizhao , Xu Tiantong
Published: April 2022

This paper proposes a Micro Electro Mechanical Systems piezoresistive accelerometer based on a whole SiC substrate. Compared with Si-based sensors, SiC-based sensors have stronger mechanical advantages and unique advantages for applications in ultra-high temperature environments. The characteristics of the accelerometer are designed and numerically simulated, and the accelerometer is evaluated in terms of stress load and working frequency band. An innovative design is carried out to eliminate the stress concentration phenomenon in the corner area of the sensor, which guarantees the working safety of the fragile structure of SiC. After fabrication, packaging and vibration experiment, it is found that the sensor’s working sensitivity can reach 0.21mv/g, and its linearity can reach 98%.
Research on Manufacturing Technology of New Energy Vehicle Based on NDT
Authors: Wang Yiyun , Fan Guangfa , Feng Ling
Published: April 2022

For the detection of laser welding defects of new energy vehicles, the traditional detection methods are inefficient and have limited accuracy. The existing visual detection methods mainly use area array cameras and image processing algorithms for detection. The image acquisition efficiency of the area array camera is low. The traditional image processing methods are vulnerable to the strong reflection on the surface of new energy vehicles, and the recognition speed and accuracy are limited. Therefore, in this paper, the linear array high-resolution camera is used for two-dimensional image acquisition, and the deep learning method is used for the recognition of weld defects. Based on the single-stage target detection network, the YOLO network is optimized according to the particularity of weld defects. The weld data set and defect data set are prepared, and the data set is used to train the optimized YOLO model. The feasibility of the method is verified by experiments, which can meet the mainstream weld length detection standards in the automotive industry.
Seismo-acoustic signal extraction from shallow sea seabed seimic wave field based on F-K method
Authors: Tang Kun , Cheng GuangLi , Liu Bao
Published: April 2022

Aiming at the numerical simulation of shallow sea seismic wave field, the finite element theory is used to establish the sea water and seabed models respectively, and then the boundary conditions of the sea water and the seabed fluid-solid coupling are constructed according to the fluid-solid coupling theory. This method can be used to quickly predict the shallow sea seismic wave field, based on this method, the vertical displacement of seabed seismic wavefield is carried out. On this basis, adopt F-K(frequency-wavenumber) method, one kind of two-dimesional Fourier transforn, to analyze wave components. Lastly, according to the principle of apparent velocity filtering, the seismo-acoustic signal (Scholte wave) in shallow sea seismic wave field is extracted.
Based on Arduino Design of Intelligent Exploration Vehicles
Authors: Liu Zhijun , Yang Chenglong , Xi Wen
Published: April 2022

This paper details the design and implementation of the hardware circuit of the intelligent cart motion control system, and uses a variety of virtual reality and visual sensing technologies to design an environmental detection and search and rescue robot under complex conditions. Infrared technology is used to achieve the function of automatic obstacle avoidance of the trolley, ultrasonic technology is used to achieve the function of distance measurement, Bluetooth is used to achieve the function of wireless remote control of the trolley, GPS technology is used to display the geographical position of the trolley, a homemade bionic robotic arm is installed, and the robotic arm servo can be controlled by PC upper computer, Bluetooth and homemade body remote sensing controller to work to achieve the removal of obstacles and unknown environment and dangerous areas The information is collected through a PC, Bluetooth and a home-made body telemetry controller.
Pipeline Laser Methane Detector Based on TDLAS Technology for In-situ Direct Measurement
Authors: Wang Yao
Published: April 2022

In order to quickly detect methane gas in real time, solve the defects of the traditional “extraction method” methane concentration measurement of gas pipeline based on pump suction or differential pressure sampling, and ensure the sensor’s performance requirements for resolution, a pipeline laser methane detector for in-situ direct measurement, based on TDLAS technology, has been developed. By studying effect of different chamber length on the resolution of different concentrations of methane gas, the gas chamber with length in the range of 4∼6cm can meet the performance requirements as much as possible, and the detector combine with the processing circuit designed with low power consumption for concentration demodulation. Test has shown that the measurement error in the range of 0%∼10% is less than ±0.05%CH4, and the measurement error is less than ±5% of the true value in the range of 10%∼100%.
Research on excavation and identification method of typical interference signal during transformer partial discharge test
Authors: Liu Rui , Lu Yangze , Huang Meng , Xie Qijia , Tu Yalong
Published: April 2022

—In order to remove interference signal and external discharge signal during partial discharge test and get the effective signal of partial discharge, this paper carries out the research of typical interference signal mining and identification method for transformer partial discharge test. Firstly, based on the experience of previous researchers in partial discharge research, 47 feature parameters including statistical, texture and shape features are extracted, and the original feature space is constructed based on them, which provides the data basis for the optimization of the feature space and signal classification identification later. Next, the random forest algorithm is used to measure and rank the importance of the feature parameters, and the original feature space is optimized according to the ranking results to obtain the optimized feature space. Finally, the optimized feature space is used as the input of linear discriminant analysis algorithm and K-nearest neighbor algorithm to classify and identify the local discharge signal and typical interference signal, and the recognition accuracy of these two classification and identification algorithms is compared and analyzed, and the K-nearest neighbor algorithm is selected as the final classification and identification algorithm.
A logical reasoning-based method for sensing the operating status of equipment
Authors: Li YongSheng , Duo XiangYang , Yang Ming , Liu ShengNan , Yu Yang , Zhou Ming
Published: April 2022

Grid equipment monitoring is to achieve comprehensive perception, rapid analysis and accurate disposal of grid operation status. As the scale of the grid continues to expand, many problems such as low efficiency in single point-based alarming, complicated and difficult process, irregular work norms, etc., have occurred in the current operating mode, which greatly restricts the improvement of management level of monitoring operation. Based on the correlation between substation monitoring information and monitoring equipment operation, we establish the correspondence between primary equipment such as main transformer, busbar, line and capacitor and the corresponding telemetry such as current, voltage, active power, reactive power and frequency. Then we analyze the occurrence mechanism of power grid equipment operation events, sense the equipment operation status, and realize timely and accurate sense and push of equipment operation defects and faults, thereby improving operational efficiency of monitoring devices.
Highly Efficient Low Noise Solutions in ECG Signals
Authors: Liu Fengru , Xu Yijie , Yao Yuan
Published: April 2022

This paper aims at helping researchers develop low-noise ECG monitors and analyze existing solutions for eliminating noise in ECG signals. A brief introduction of ECG signal, main kinds of noise in ECG signal and a summary of different kinds of low noise solutions is given. The components of the ECG signal and the origin of noise in the ECG signal are analyzed first. In order to find optimized solutions for eliminating the noise, highly effective solutions are listed and analyzed. Solutions are divided into three main directions, which are circuit design, signal processing and machine learning. Specific practical examples from former research and analyses for each direction help the reader understand and select different ways of eliminating noise in ECG signals. After introducing three directions, a summary and further improvement are given to help readers have a horizontal comparison between solutions.
Thompson-Lampard Theorem for Dielectric Characteristics Detection of Generator Stator Insulation
Authors: Liu Boyan , Lei Yu , Sun Shitao , Zhang Jie
Published: April 2022

The insulation of large generator stator winding will be gradually aging in the long-term operation process. The traditional aging test method cannot accurately locate the non-penetrating local defects of winding. Interdigital electrode is widely used in the fields of environmental monitoring and food detection because of its excellent characteristics such as self-closing and unidirectional penetration, but it has not been popularized in the identification of generator insulation aging. The paper proposes an interdigital electrode structure based on the Thompson-Lampard theory. The electrode suitable for dielectric characteristic detection of stator winding, and the electrode structure is optimized by using the finite element method from the parameters of signal strength, sensitivity and penetration depth. With the help of optimising, the measuring accuracy of the electrode can reach 0.1 level. Then, the different moisture conditions of water-cooled generator and air-cooled generator are simulated to verify the feasibility that interdigital electrode can detect insulation moisture which is an important factor in accelerating insulation aging. Finally, the moisture depth detection results show that the electrode combination based on the Thompson-Lampard theory can be used to locate moisture depth accurately, it is of great significance for the prevention of insulation aging and the pre-diagnosis.
Method of Cogging Torque Reduction for Built-in Permanent Magnet Synchronous Motor
Authors: Yang Yong , Wang Xudong
Published: April 2022

Cogging torque is one of the main factors that deteriorate the performance of permanent magnet motor. In order to reduce the cogging torque of built-in permanent magnet motor, a method of optimizing Rib and DminMag to reduce groove torque of built-in permanent magnet motor was proposed. Firstly, the relationship between Rib and DminMag and groove torque is analyzed through the expression of groove torque. Secondly, the optimal Rib and DminMag were found by finite element parametric calculation, and compared with the pre-optimization groove torque, the groove torque was significantly reduced. Finally, the main performance of motor before and after optimization is not significantly reduced.
High-speed train speed tracking control based on active disturbance rejection control strategy
Authors: Feng Chenjiang , Kuang Wenzhen
Published: April 2022

The speed tracking control of high-speed trains has the characteristics of nonlinearity, time delay, and multi-factor interference. Aiming at this, a train speed tracking algorithm based on active disturbance rejection control strategy is proposed. First, establish a train control model based on the train dynamics model. Secondly, design a second-order active disturbance rejection controller to set and compensate for unknown disturbances, and then convert the known train parameters to the controlled object for system simulation, the target speed curve is tracked, which proves the feasibility of the auto disturbance rejection control algorithm. Finally, compare traditional PD control algorithms in terms of anti-jamming performance and tracking error. The results show that the high-speed train speed controller based on active disturbance rejection control has greatly improved the tracking speed accuracy and the robustness of the control system.
Research on urban rail train control system based on train to train communication
Authors: Ma Yuanyuan , He Tao
Published: April 2022

The new train control system VBTC based on train to train communication adopts the idea of on-board centralization, regards switches and sections as trackside resources, integrates the functions of interlocking and zone controller into on-board, and the train independently manages line resources and determines the train operation control scheme. Compared with the existing CBTC system, VBTC system not only simplifies trackside equipment, but also improves operation efficiency, reduces operation and maintenance costs, and can better solve the problems of shortage of commissioning time and limited room space during overhaul and reconstruction of old lines. This paper analyzes the key technologies of train control system under train to train communication technology, designs the structure of VBTC system on-board module and object controller, and analyzes the control line resource flow of trackside object controller. VBTC train control system breaks through the inherent mode that all rail transit train control systems rely on station and trackside equipment to realize train operation control, and completely relies on on-board train control, which is in line with the development trend and direction of train control system.
Analysis and design of precise testing instrument chassis considering electromagnetic shielding
Authors: Hou Xuwei , You Li , Li Jingjing , Wang Huiyuan
Published: April 2022

In this work, the issues regarding the mechanism and structural design of electromagnetic shielding technology are introduced. In accordance with the use requirements of precise testing instruments, the precautions in the chassis design with respect to electromagnetic shielding are determined. Moreover, the approach to improve the chassis through experiments is proposed, and the test shows that the improved chassis can meet the requirements of shielding.
Design of UAV target tracking controller based on visual servo
Authors: Wang Hongfei , Shi Yongkang
Published: April 2022

The task of tracking a moving target by the UAV has two major challenges: one is that the multi-angle and multi-scale changes caused by the target’s movement make the target detection more difficult, the other is that the stability and accurate of target tracking are difficult to guarantee. In order to solve these problems, using monocular vision to get the image information of the target and YOLOv4 is used to detect multi-angle and multi-scale moving targets. Then based on the image visual servo control method, the PID controller is designed, and the deviation between the target pixel and the ideal pixel is used as the input, the output of the controller is the desired pixel speed of the UAV in image coordinate system. the tracking speed of the UAV under the machine system is solved according to the image Jacobian matrix, and a tracking strategy is designed to improve the tracking accurate and stability. In the process of target tracking, the difference between the x-axis and Y-axis coordinates of the target center point and the image center point is less than 30 pixels. The results show that the proposed algorithm can keep the target in the center of the image.
Design and research of electromagnetic generator based on Helmholtz coil
Authors: Chen Jinshan , Shi Yongkang
Published: April 2022

According to the technical requirements of electromagnetic-eddy current spin-off test for space targets, an electromagnetic generator is designed based on the working principle of the Helmholtz coil, the utility model is composed of a pair of square coils of the same structural size and turns of the coils. The magnetic field generated by the electromagnetic generator is simulated and analyzed by using the Maxwell electromagnetic simulation software, and the distribution of the magnetic field on the X axis, Z axis and the surface of the square coil is observed, the Tesla Meter was used to measure the magnetic field at 27 locations in the central region of the electromagnetic generator. The results show that the uniform magnetic field range, the magnetic induction and the uniformity of the magnetic field produced by the electromagnetic generator can meet the requirements of the electromagnetic eddy current damping test.
Development and application of a double-break vacuum on-load tap-changer
Authors: Zhou Kai , Jin Lei , Luo Wei
Published: April 2022

—At present, the mainstream large-capacity vacuum on-load tap-changer generally only uses a single resistance transition and there is a risk of breaking inter-stage short-circuit current. In order to improve the operational reliability of the vacuum tap-changer, this paper innovatively developed a double-break vacuum on-load tap-changer using dual transition resistances, which avoids the problem of inconsistent loads between the main vacuum tube and the transition vacuum tube, and theoretically avoids the inter-stage short-circuit accident, and completed the development, type test and trial run of the tap changer.
Calibration analysis of gas relay
Authors: Ma Chunlong
Published: April 2022

—Gas relay is the main protective element of transformer internal fault, which can sensitively respond to transformer short-circuit fault, core fault, internal turn to turn short-circuit of winding, insulation deterioration and oil level drop. Therefore, it is necessary to regularly compare and verify the gas relay. This paper briefly introduces the operation principle and calibration method of gas relay, analyzes in detail the reason why there is no specific standard for the calibration of gas relay setting value, and analyzes the factors affecting the flow rate setting value.
Security control of unstructured data in the power IoT for isolation network between internal and external
Authors: Yang Ruxia , Wang Di , Liang Fei
Published: April 2022

As a key national infrastructure, the safety of the power grid is an overall and strategic issue that affects the development of the national economy and society. With the popularization and development of the Internet of Things in the power industry, power Internet of Things terminal equipment has become a key target of network attacks. Using network attacks to damage power Internet of Things equipment has a strong detrimental power. As the main data storage method of the power Internet of Things, the security management and control of unstructured data has become the focus of the power Internet of Things security. This paper proposes a reformulation of access control policies based on the different attribute states and trust levels of power Internet of Things terminal equipment to reduce its access control authority, and on this basis, proposes a dynamic access control based on the isolation of internal and external networks. The detailed function design of each core security protection component is given, and the component module is explained.
Design of Flexible Spherical Fruit and Vegetable Picking End-effector Based on Vision Recognition
Authors: Chen Meng , Chen Feng , Zhou Wen , Zuo Ruoyu
Published: April 2022

In order to solve the problems of poor versatility and high clamping damage rate faced by the end-effector of picking robots in today’s picking operation, a universal spherical fruit and vegetable picking die end-effector based on vision recognition with adaptive flexible force clamping is designed. This end-effector is a pneumatic three structure, while integrating a small air source device, in the control of a variety of sensors, through the fusion of multiple sensing and algorithm improvement and other ways, so that the mold end-effector in the picking operation, through visual recognition to determine the type of fruit and vegetables, and then provide the optimal gripping force. At the same time, the fingertip is equipped with a pressure sensor to adjust the pressure output in real time to achieve the overall picking process, the pressure is kept constant, and in the judgment of the completion of fruit and vegetable picking, a torque sensor is equipped to presume the completion of the picking operation by twisting the fruit strength. Finally, the actual product was made and several fruit and vegetable simulation experiments were carried out. The experimental structure is good, which verifies that the end-effector has good versatility and flexibility.
Development and application of AC section power loss protection device
Authors: Zhang Hongyue , Zhou Qiang , Fan Zhanfeng , Song Hongtao , Liu Zhiwen , Niu Zhilei , Deng Maojun , Shuai Jiang , Li Wenzheng , Li Xinwen
Published: April 2022

—The so-called AC section power loss refers to the loss of all AC power supplies of the system on this side. After the AC section at the receiving end of the converter station loses power, it will lead to serious AC overvoltage, and the energy of the arrester will increase sharply at the same time, which will seriously affect the safety of the equipment. In view of this situation, this paper studies the action mechanism of AC section power loss protection, and gives the design scheme of AC section power loss protection device. The developed protection device has been verified by RTDS simulation test, passed the third-party detection test of a detection and Research Institute, and is running on site. The field operation is good. The device is not only suitable for conventional DC system and flexible DC system, but also for some occasions where regional stability needs to be considered.
Design of Permanent Magnet Synchronous Motor Power-assisted System Based on Field Oriented Control Algorithm
Authors: Huang Weiqiang , Lu Kai , Huang Weiqiang
Published: April 2022

Aiming at the integrated surgical robot, a set of power-assisted control system is designed to overcome the transmission resistance between master and slave hands, so that the operator feels light and comfortable during operation. The system includes permanent magnet synchronous motor, driver, controller, torque sensor, upper computer. The field oriented control algorithm is discussed and is used to control the permanent magnet synchronous motor. STM32 is used as the main control chip, DRV8301 is used as the driving chip, and the upper computer software, which has human-computer interaction interface and real-time torque signal display interface, is written by C#. A non-contact torque sensor and corresponding signal processing module is designed. The experimental results show that with the operator’s start-stop and reversing action, the q-axis current of the motor changes rapidly, and the amplitude of steady-state changes is small. This means that the designed system has the advantages of stable assist torque and fast response.