Table of Content

15 April 2021 Volume 34 Issue 4

  

Anonymous Interaction Algorithm of Access Control in Searchable Voice Encryption Mechanism

HE Shaofang,ZHOU Li

Electronic Science and Technology. 2021, 34(4):  1-5.  doi:10.16180/j.cnki.issn1007-7820.2021.04.001

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In view of one-to-many and multi-user single server model of searchable voice encryption mechanism in cloud environment, a public key anonymous interaction algorithm of access control is proposed. Based on the difficulty of discrete logarithm problem, this algorithm constructes a new polynomial using the binary random sequence to generate the user private key information, and realizes the anonymous authentication and symmetric key transfer through the interaction between the user and the cloud server. The analysis shows that the proposed method not only realizes the anonymous authentication of users, symmetric key transfer and dynamic addition and deletion of user safely and effectively, but also has the advantages of complete collusion resistance, fully revoke and recoverability.

Time Domain Parameter Measurement of Aliased Multi-Component LFM Signals Based on HAF

WU Zhenyu,XIA Houpei

Electronic Science and Technology. 2021, 34(4):  6-11.  doi:10.16180/j.cnki.issn1007-7820.2021.04.002

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In view of the problem that the aliasing pulse radar signal parameter measurement method based on HAF could not effectively measure the signal time-domain parameters, this study proposes a time-domain parameter measurement method of aliasing multi-component LFM signal based on HAF. The proposed method uses the phase coefficient estimates obtained by the HAF method to convert each LFM signal component into a single frequency signal component with the same time domain parameters. The single frequency signal component is separated by filtering and a suitable threshold is selected to measure the time domain parameters, so as to realize the time domain parameter measurement of each component of the aliased LFM signal. The experimental results show that this method can effectively measure the time-domain parameters of the signals, and then combined with the results of HAF method, the parameters of the LFM signal can be measured completely. The proposed method has low computational complexity and high accuracy of measurement results, and the measurement error is less than 1% when the signal-to-noise ratio is 3 dB.

Fish Recognition Algorithm Based on Improved AlexNet

XUE Yongjie,JU Zhiyong

Electronic Science and Technology. 2021, 34(4):  12-17.  doi:10.16180/j.cnki.issn1007-7820.2021.04.003

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Due to the various species of fish, and the influence of different light and background environments, the recognition accuracy of some traditional fish recognition algorithms bases on color texture or feature point extraction is reduced, and good classification results cannot be achieved. To solve the problem, based on the existing AlexNet convolutional neural network, this paper proposes one method to speed up model training by reducing redundant convolutional layers. An item-based soft attention algorithm is applied to the improved AlexNet convolutional neural network model, which consists of four convolutional layers, one item-based soft attention layer, and two fully-connected layers. Meanwhile, a fish recognition model is established using transfer learning methods.The test results show that the average recognition accuracy of the proposed algorithm achieves 97.43%, which is 4.08% higher than the original AlexNet model, and the average recognition rate of some fishes achieves 99.31%, and time consumption of fish recognition is reduced by 35%. In conclusion, compared with state-of-the-art fish recognition algorithms, the fish recognition algorithm proposed in this study achieve higher accuracy, lower model complexity, and stronger robustness.

Driver Design of Variable Capacitance Linear Electrostatic Motor

YUAN Yiwen,LI Huafeng,LI Xilong

Electronic Science and Technology. 2021, 34(4):  18-23.  doi:10.16180/j.cnki.issn1007-7820.2021.04.004

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In view of the problems of poor low-speed performance of the variable-capacitance linear electrostatic motor under the sine wave-based driving method and the complicated design of the large-scale converter, a driving method based on the square wave is proposed. The stator electrodes are divided into A-phase electrodes, B-phase electrodes, and C-phase electrodes. Each phase electrode is connected to a square wave drive signal with a magnitude of 1 kV at different timings. The electrostatic force caused by the potential difference between the stator and the mover is used as the driving force of the motor. In order to obtain a compact and efficient power supply and a three-phase square wave with an amplitude of 1 kV, a DC-DC adjustable DC power supply based on a push-pull topology and a drive circuit based on a half bridge are designed. The feasibility of this method is proved by simulation and experiments. At low speeds, the drive waveforms at both ends of the motor are smooth, and the motor can move forward, forward and reverse smoothly. Simulation experiments show that at low speeds, the drive waveforms at both ends of the motor are smooth, and the motor can move forward, forward and reverse smoothly, indicating the feasibility of the proposed method.

Research Development of Initial Rotor Position Detection of Permanent Magnet Synchronous Motors

LI Yifei,JIANG Quan

Electronic Science and Technology. 2021, 34(4):  24-33.  doi:10.16180/j.cnki.issn1007-7820.2021.04.005

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Permanent magnet synchronous motors are widely used in the field of motor drives because of their high efficiency and small moment of inertia. In the field of high-performance drive control, there is a high demand of reliable and fast startup of the motor, so the speed and position information of the rotor is essential. The accuracy of the initial position estimation of the permanent magnet synchronous motor will directly determine whether the motor can be started and the performance of the motor control. Position sensors are bulky, costly, and sensitive to the environment, which limits the application range of permanent magnet synchronous motors. Sensorless technology has gradually become a research hotspot. In this study, the detection methods of initial rotor position of permanent magnet synchronous motor are discussed. The study respectively introduces the rotor position detection method based on the salient pole effect of the magnetic circuit structure of the motor or the non-linear saturation characteristic of the stator core and the specific implementation scheme. Finally, the initial position detection methods of permanent magnet synchronous motor are summarized and predicted.

Design of Efficiency Parallel HDMI 2.0 Encoder Based on FPGA

GONG Jialiang,TANG Qingshan,BAI Chuang

Electronic Science and Technology. 2021, 34(4):  34-40.  doi:10.16180/j.cnki.issn1007-7820.2021.04.006

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An efficient parallel HDMI 2.0 encoder is designed to solve the problems of poor scalability and large circuit area in the design of multi-channel video display system. The compatibility of HDMI 2.0 encoder has been improved through the compatibility design of HDMI version 1.4 and 2.0 standards. The scalability and portability of HDMI 2.0 encoder are improved by simplifying functions and providing user-friendly data interfaces. Through parallel design, the ECC circuit and the scramble circuit are kept at the same data rate as the entire encoder, and a pipelined design method was used to implement the parallel encoding of the video data encoding circuit. The result analysis, function simulation and on-board test are carried out and their results show that the HDMI 2.0 encoder conforms to the HDMI standard and can stably perform encoding and output. The results also showed that the coding ability of ultra-HD video is possessed by HDMI 2.0 encoder designed in parallel, which can reach the maximum coding bandwidth of HDMI 2.0 standard.

An Improved Image Shadow Removal Method

HU Chen,HU Demin,HU Yuyuan,CHU Chengwei

Electronic Science and Technology. 2021, 34(4):  41-46.  doi:10.16180/j.cnki.issn1007-7820.2021.04.007

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In view of the problems of illumination unsaturation and texture inconsistency after shadow removal, a shadow removal method based on Retinex is proposed in this study. Based on the relationship between incident light and reflected light in Retinex theory, this method reevaluates the incident light map, assignes the average value of pixels in the three RGB channels to the target pixel point, and improves the gradient descent method. By adjusting the adaptive weight, the problem of illumination unsaturation and texture inconsistency after shadow removal is improved. The experiments on the UIUC data set prove that the root mean square error ratio of the experimental results is reduced to 0.4106, which verifies the effectiveness of the proposed method.

Research on Human Sitting Posture Recognition Test Based on Pressure Sensor

SUN Mingyang,MENG Cairu

Electronic Science and Technology. 2021, 34(4):  47-51.  doi:10.16180/j.cnki.issn1007-7820.2021.04.008

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Sit recognition is of great significance to sit monitoring. In view of the problems of low accuracy, complex debugged and high cost of the existing sitting recognition device, a method of sitting posture recognition based on pressure sensor is introduced in this study. The method realizes the recognition of different sitting postures according to the difference of the pressure values of the pressure sensors at 8 monitoring positions on the upper body of the human body under different sitting postures. The test results show that the proposed method can identify four sitting positions, and under the same height, the pressure value is positively related to the weight. In the four sitting positions, the pressure values of the thoracic and lumbar vertebrae are significantly higher. These obtained results indicate that this method can be applied to sit sitting posture monitoring equipment, to realize the recognition and monitoring of sitting posture.

Research on Dynamic Reconfiguration of Distribution Network with DG Based on Game Theory

WANG Yumei,YANG Wenliang

Electronic Science and Technology. 2021, 34(4):  52-58.  doi:10.16180/j.cnki.issn1007-7820.2021.04.009

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In this study, the problem of clean energy output power dissipation in distribution network with DG in invertigated. The multi-objective cooperative game is used to reconstruct the distribution network in each period. A multi-objective dynamic reconstruction model is established on the basis of cooperative games with multiple reconstruction targets as players. The model is solved by the route exchange method of the drosophila optimization algorithm improved by the idea of simulated annealing method to obtain the optimal solution in each time period, and then the most dynamic reconstruction scheme of the research object is obtained according to the time period division.The IEEE33-node power distribution system including wind power station and photovoltaic power station is simulated, and the optimal dynamic reconfiguration scheme of power distribution network considering both operation cost and clean energy utilization rate is obtained. During the whole reconfiguration process, only 14 actions are taken, the network loss is reduced by 31% and the DG consumption is increased by 115%, which verifies the effectiveness of the proposed mathematical model and solution scheme.

Overview of Sensorless Control Technology for Full Speed Range Permanent Magnet Synchronous Motors

ZHOU Tao,JIANG Quan

Electronic Science and Technology. 2021, 34(4):  59-69.  doi:10.16180/j.cnki.issn1007-7820.2021.04.010

Abstract ( 1632 )   HTML ( 49 )   PDF (1498KB) ( 403 )  

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Currently, the control system of permanent magnet synchronous motor is developing towards high efficiency and low cost. In view of the problems of the conventional mechanical position or speed sensors, such as large size, high cost, inconvenient installation and low reliability in special applications, sensorless control technology is widely used in the field of electric drives. The key to realize sensorless control is to detect the rotor position or speed of the motor. This study classifies and summarizes the various methods of sensorless control technology of permanent magnet synchronous motors in the range of zero low speed, medium high speed and full speed. The principle and characteristics of various methods are introduced, and their advantages and disadvantages are analyzed and compared. Finally, the research focus and development trends of sensorless control methods for permanent magnet synchronous motors are prospected.

Geomagnetic Matching Localization Algorithm Based on Affine Transformation

YAN Yuling,TANG Qingshan,BAI Chuang

Electronic Science and Technology. 2021, 34(4):  70-74.  doi:10.16180/j.cnki.issn1007-7820.2021.04.011

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For the problem that the positioning error of inertial navigation system accumulated with time, a geomagnetic matching positioning algorithm based on affine transformation is proposed. The correlation constraint between the matched trajectory and the measured geomagnetic field eigenvalue is established by the square difference algorithm. The constraint function is expanded and discretized by Taylor, and the affine transformation model is introduced. The constraint function is transformed into a multivariate index function of the displacement, angle and contraction error of the curve. According to the relativity principle, the geomagnetic matching problem is transformed into solving nonlinear equations. The iterative and numerical method in Mathematica is used to solve the nonlinear equations. The obtained solutions are input into MATLAB for matching and positioning. Experiments show that the final registration point of the matched track differs from the end point of the real track by 293.3 m, and the longitude and latitude errors between the matched track and the real track are 0.003° and 0.000 4° respectively, which verifies the feasibility of the proposed algorithm.

Bearing Fault Diagnosis Algorithm Based on One-Dimensional WConv-BiLSTM

YAN Shuhao,QIAO Meiying

Electronic Science and Technology. 2021, 34(4):  75-82.  doi:10.16180/j.cnki.issn1007-7820.2021.04.012

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In view of bearing fault diagnosis under different signal-to-noise ratio noise interference, a bearing fault diagnosis model based on one-dimensional wide convolution kernel convolutional neural network and bidirectional long short-term memory neural network is established. The bearing vibration signals are used as input to the proposed model, and the short-time Fourier transform is used to transform the vibration signal into the time-frequency figures. Convolutional neural networks with wide convolution kernels and bidirectional long short-term memory neural networks are applied to extract the spatial and temporal characteristics of data, and classification is achieved through dense layers. Data augmentation, mini-batch, and batch normalization methods are utilized to enhance the anti-noise performance of the model. The test uses the CWRU bearing fault data set, and adds noise with different SNR to construct noise interference tests. The experiments show that proposed model has great noise resistance, and can achieve 98% accuracy of fault recognition with a signal-to-noise ratio of 2 dB.

Publication and Development of Academic Journals in the Context of High-Speed Communication

CHEN Xiaoyun,LI Qingjun

Electronic Science and Technology. 2021, 34(4):  83-86.  doi:10.16180/j.cnki.issn1007-7820.2021.04.013

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In 2019, China officially entered the "5G first year", and China has been the promoter and builder of 5G technology. In the future, 5G technology will also comprehensively drive the product flow and information flow on the Internet, and change the shape of the whole information society. The publishing industry is the first to take the lead. 5G has strengthened the communication channel of periodicals with its advanced technology and brought the latest experience to users, which strongly changes the future market trend of academic journals. In this sutdy, the development prospect of academic journals publishing industry is discussed and analyzed according to the current situation of academic journals development in China and the application of high-speed communication technology.