Table of Content

15 June 2020 Volume 33 Issue 6

  

Human Gait Recognition and Identification with Passive RFID

WANG Ge,XI Wei,DING Han,ZHAO Kun,ZHAO Jizhong

Electronic Science and Technology. 2020, 33(6):  1-7.  doi:10.16180/j.cnki.issn1007-7820.2020.06.001

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As a rising biometric features recognition technology, human gait recognition has the advantages of long distance and difficult to be forged. As a result, human gait recognition has been widely used in many applications, including smart monitoring system. Current human gait recognition methods have their own problems of complex algorithms calculation, high user participation and extra hardware requirements. Aiming at these problems, a new method for user gait recognition based on passive radio frequency technology was proposed in this study. This method used the passive radio frequency tags that have been widely deployed in the access control system. The proposed method calculated the dynamic moving speed of the user by analyzing the phase profiles of tags, compensated the samples by considering multiple signal profiles of tags, and extracted the frequency domain recognition features. The experiments showed that this method could achieve an accuracy up to 91.87% , and the time delay was only 0.129 s. In conclusion, this method realized a highly efficient and accurate human gait recognition and identification with limited training data and user participation.

Design of Chipless RFID Tag Based on Hybrid Coding

SUN Haijing,CHEN Qiang,YANG Jiao,ZHOU Ling

Electronic Science and Technology. 2020, 33(6):  8-12.  doi:10.16180/j.cnki.issn1007-7820.2020.06.002

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In order to reduce the cost of traditional RFID tags and improve the tag coding capacity, by using the method of mixed coding of amplitude and frequency position, a chipless RFID tag with large capacity coding function was designed, which was composed of microstrip main transmission line, ultra-wideband antenna with orthogonal transceiver and resonator with different length. Simulation and test results showed that in the 2.37 6.17 GHz frequency band, the encoding capacity of 20 bit could be obtained, and the encoding capacity of 60 bits could be obtained after mixed encoding. The 8 bit chip-less label of the three coding states measured in the field showed that the position of the resonance point only fluctuates within a small range of 10 MHz, which ensured the accurate identification of the resonance point and realized the preset coding function. This kind of chipless label with large capacity coding function could reduce the cost of the IOT system and replace the laser bar code in the field of logistics.

Fabrication of Flexible RFID Metal Antenna Based on Paper Substrate

YAN Chuan,CHENG Siyuan,WANG Kang

Electronic Science and Technology. 2020, 33(6):  13-17.  doi:10.16180/j.cnki.issn1007-7820.2020.06.003

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The porous characteristic of the paper substrate causes penetration and diffusion of the liquid material on the surface. Therefore, it is extremely difficult to form an RFID tag metal antenna by electroless deposition on the surface of the paper substrate. Aiming at this problem, the stannous chloride colloid solution was applied to avoid the catalytic ink penetration in the paper-based substrate. Moreover, paper substrate was immersed in chitosan solution, which could bring functional group and improve the conductivity and adhesion of RFID metal antenna. The SEM, XRD, EDS and adhesion test of the metal layer antenna of the RFID tag proved that the surface of the metal layer of the tag antenna had advantages including dense surface, high crystallinity, good adhesion, low resistivity (2.58×10 ^-8 Ω·cm), good mechanical properties (1 000 bending test).

Application of Particle Swarm Optimization Based on Beetle Antennae Search Algorithm in PID Parameter Tuning

WU Qiang,ZHANG Wei,YANG Huiting,WANG Chaoying

Electronic Science and Technology. 2020, 33(6):  18-23.  doi:10.16180/j.cnki.issn1007-7820.2020.06.004

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PSO is widely used in various optimization events, including PID parameter tuning. However, the traditional particle swarm optimization has a slow convergence speed in some cases and is easy to fall into local optimum values. Aiming at this problem, this study proposed a new efficient BAS integrated into the PSO algorithm. The BAS algorithm was applied to the global optimization process of the traditional PSO algorithm, so that it can jump out of the local optimum better. At the same time, because the BAS algorithm is a single individual algorithm, it is easy to fall into local optimum because of premature convergence. By combining with traditional PSO, the richness of BAS was significantly enriched. After 20 independent tests on Schaffer function, compared with the traditional PSO, BAS and the cited references studies, the proposed algorithm achieved better optimization results. Finally, the algorithm was applied to the optimization of the PID parameters of unstable objects. Compared with the PSO and the improved PSO, the indexes such as ts, tr, IAE and ISE had achieved better improvement.

Design of a Automotive Voltage Regulator Chip Based on BCD Process

YANG Renjing,WANG Yi,ZHANG Yugui,SHI Chuanfei

Electronic Science and Technology. 2020, 33(6):  24-28.  doi:10.16180/j.cnki.issn1007-7820.2020.06.005

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Aiming at the problems of large volume, poor stability and short service life of automotive voltage regulator, a voltage regulator chip for automobile was proposed in this paper. In order to stabilize the output voltage of generator, the chip adjusted the average excitation current of the generator by using pulse-width modulation technology. Meanwhile, a low-temperature drift, high-precision voltage reference source and protection circuits were integrated in the chip. This chip was designed based on 0.5 μm BCD process and simulated by Cadence Spectre. The simulation results showed that the operate voltage range of chip was 720 V, the quiescent current of chip was 472 μA, the voltage regulation range was 1020 V, the reference voltage was 1.16 V, the operating temperature range was -40125 ℃, and the temperature coefficient of reference voltage was 8.4 ppm·℃ ^-1. In addition, when the voltage at the output of the generator fluctuated, the chip could stabilize the voltage.

Cross-correlation Time Delay Estimation Optimization Algorithm Based on LMS Adaptive Filtering

WEI Wenliang,MAO Yulong

Electronic Science and Technology. 2020, 33(6):  29-34.  doi:10.16180/j.cnki.issn1007-7820.2020.06.006

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In multi-station time difference positioning system, when using the cross-correlation method based on LMS adaptive filtering for time delay estimation, the fixed step factor has a large contradiction between convergence speed and steady-state offset, which affects the accuracy of delay estimation. Aiming at this problem, a cross-correlation time delay estimation optimization algorithm based on piecewise variable step size LMS adaptive filtering and Hilbert difference was proposed in this study. Firstly, the piecewise variable step size LMS adaptive filtering was used to filter the signal, then the filtered signal was cross-correlated, and finally the peak of the correlation function was sharpened by the Hilbert difference method to obtain higher delay estimation accuracy. Under the same conditions, the time delay estimation accuracy of different algorithms was simulated and analyzed. The results showed that the proposed optimization algorithm had higher delay estimation accuracy, and the prediction accuracy could be improved by 2.2% compared with the traditional method under different SNR, indicating proposed algorithm presented good anti-noise performance.

Dual Master-Slave Output Strategy Based on Switching Capacitor DC-DC Converter

WU Hanhan,BU Gang

Electronic Science and Technology. 2020, 33(6):  35-39.  doi:10.16180/j.cnki.issn1007-7820.2020.06.007

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The linear regulation and load regulation of traditional DC-DC converter is not ideal. Aiming at this problem, this paper adopted a output method of dual output time division multiplexing. In the case of control switch phase interleaving, the master-slave output were transmitted respectively, and the specific modulation strategy was proposed. PFM was adopted for the master output and PSM was utilized for the slave output. Meanwhile, the concept of average frequency was introduced to realize the quantitative characterization of driving capability. Circuit design and simulation were carried out under Cadence software. The simulation results showed that the linear regulation of master output was 3.01% and the load regulation was 3.54%; the linear regulation of slave output was 3.75% and the load regulation was 4.28%.

Design of A Composite Equalization System for Lithium-ion Battery Modules

HUANG Peng,ZHENG Yuejiu,GAO Han,LAI Xin

Electronic Science and Technology. 2020, 33(6):  40-45.  doi:10.16180/j.cnki.issn1007-7820.2020.06.008

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The vehicle power battery pack is prone to deterioration in consistency during charge and discharge cycles, which may cause battery capacity attenuation and even cause security problems. In this paper, a multi-equalizer composite equalization system based on CAN communication was proposed. The system could cascade multiple equalizer, and each equalizer included an active equalization part which used the charge chip to charge low power cell. The passive equalization part which composed of resistor arrays was used to discharge high power cell. In addition, each equalizer was equipped with a high-power resistance for battery module overall fast discharge. In order to achieve the purpose of composite equalization, effective control strategy and equalization algorithm were designed. The simulation and physical experiments were set up to validate control strategy and equalization algorithm. In the physical experiment, the voltage range of the battery pack was reduced from 200 mV before equalization to 20 mV after equalization, indicating that the consistency of the battery pack was obviously improved with the equalization system.

Research on A Multi-area Air-cooled Precise Temperature Control System with High and Low Temperature

CHEN Mingfang,ZANG Jiaxiu,ZHANG Yongxia

Electronic Science and Technology. 2020, 33(6):  46-51.  doi:10.16180/j.cnki.issn1007-7820.2020.06.009

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In order to solve the problem of high-temperature and high-temperature control of multi-zone air-cooling, this study designed a new large-space and multi-area control method. The method adopted PLC as the control core, using PT100 temperature sensor as the temperature measuring component, and the temperature as the temperature of the cooling and heating unit. Adjusting components, combined with macro PID control algorithm, fast PWM regulation and hybrid control of the heating and cooling unit to achieve precise control of multi-zone temperature. The user login function was developed based on MCGS configuration software. The experimental prototype test showed that the system could achieve temperature accuracy of ±0.5 ℃ in the range of -520 ℃ and temperature accuracy of ±0.1 ℃ in the range of 2060 ℃.The practical application verified that the proposed method had higher control precision, better reliability and simple operation than the conventional PID algorithm, indicating it had good promotional value.

A Multicore System Improved List Scheduling Algorithm

LUO Le,WANG Chunhua,ZHANG Duoli,SONG Yukun

Electronic Science and Technology. 2020, 33(6):  52-57.  doi:10.16180/j.cnki.issn1007-7820.2020.06.010

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The list-based task scheduling algorithm has been widely used in the field of task scheduling. The classic list scheduling algorithm randomly sorts the task nodes with the same weight in the node sorting stage. But the sorting method is rough and difficult to achieve better results. In view of this defect, this study proposed an improved list scheduling algorithm. This algorithm integrated tasks with consistent weights through special list fragments, and traversed the scheduling solution space of special list fragments to iteratively generate better scheduling lists to obtain a better scheduling results. The results of random DAG graph test showed that the proposed algorithm had excellent scheduling effect, and the average algorithm enhancement ratio was up to 15.3%, indicating the proposed method was not only suitable for multiple task map scales, but also had better scheduling performance under the condition of higher CCR and higher average access.

A Prediction Method of Receiving Signal for Ground Station Based on the Real-time Telemetry Data of Rockets

PANG Yuefeng,GU Suolin,LI Lisan,YANG Bingxian,CHU Fuyong

Electronic Science and Technology. 2020, 33(6):  58-62.  doi:10.16180/j.cnki.issn1007-7820.2020.06.011

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Flame decay is a key consideration of distributed telemetry stations in the selection of ground measurement points. The traditional method is to determine the influence of rocket flame on received signal from telemetry ground station by using β angle. In the launch of new solid rocket, the angle analysis method is inaccurate to predict the received signal of telemetry ground station. To solve this problem, a prediction model of received signal condition was proposed. The model was realized by characterizing the directivity of signal attenuation. Parameters of the model were determined by analyzing the actual flight attitude, position and actual tracking signal of ground telemetry equipment. Additionally, a practical calculation was given in this study to verify the method superior to the traditional method.

Design of Living Face Recognition System Based on Web Camera

WANG Chunjiang,ZHANG Meng,ZHANG Jianfei

Electronic Science and Technology. 2020, 33(6):  63-68.  doi:10.16180/j.cnki.issn1007-7820.2020.06.012

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ing at the problems of large size, single function and high cost of the current monitoring system platform, this paper designs an online living face recognition system based on the HiSilicon 3518E platform. The system includes five parts: image pre-processing, image acquisition, face detection, face live detection, and face recognition. It also improved and optimized the deficiencies of traditional algorithms in embedded platforms. The system collected the face image through the camera and preprocessed the image to provided guarantee for subsequent image feature extraction. The extended Haar feature was used to train the classifier and the Adaboost algorithm was used to cascade face detection. The detected face used HSV and Ycbcr multi-color space the COALBP and LPQ fusion features extracted below were used to train the SVM model, perform live face detection, and finally extract LBP features from the face image to perform face recognition, and the recognition results were displayed through the WeChat applet. The experimental results showed that the feasibility of the face recognition system based on the HiSilicon web camera had certain practical value.

Simulation Study on Influence of Spiral Groove Position Characteristics on Gas Film Sealing Performance

WAN Xing,LIU Meihong,SUN Junfeng,WANG Xueliang

Electronic Science and Technology. 2020, 33(6):  69-73.  doi:10.16180/j.cnki.issn1007-7820.2020.06.013

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In order to effectively select the position of the spiral groove and determine the factors affecting the gas film sealing performance, the influence of the position characteristics of the spiral groove on the performance of the film seal was simulated in this study. With theoretical analysis and ANSYS modeling software, this paper modeled the pressure field model in two states and the two kinds of gas film structure models, including static ring slotting and dynamic ring slotting. On this basis, the static pressure distribution and shear stress distribution under static ring groove and dynamic ring groove structure were studied by FLUENT software simulation, and the influence of different operating parameters on cylindrical gas film sealing performance was further analyzed. The simulation results showed that the gas film model of the static ring groove was slightly better than the gas film model of the dynamic ring groove, and the pressure difference and air viscosity had a significant effect on the gas film sealability.

Enhanced Electrocatalytic Activity from MoS₂ for Efficient Hydrogen Evolution

LI Peizhen,CHEN Long

Electronic Science and Technology. 2020, 33(6):  74-78.  doi:10.16180/j.cnki.issn1007-7820.2020.06.014

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In view of the current problem of low number of active sites and poor conductivity of materials when MoS₂ is used as a hydrogen evolution catalyst, MoS₂/PVP composite catalyst was prepared by liquid-phase ultrasonic stripping method and centrifugal treatment in this study. PVP increased the concentration of MoS2 in the dispersion and increased the amount of catalytic active sites. 2H phase to 1T phase transition occurred during the process, which enhanced the catalytic activity. The PI substrate containing the conductive copper layer was selected as the electrode substrate, which improved the transmission efficiency of electrons between the catalyst and the electrode. The MoS₂/PVP composite catalyst was immobilized on the surface of the PI-based electrode by inkjet printing technology to prepare a catalytic hydrogen evolution electrode with an overpotential of 77 mV at 10 mA·cm ^-2 and a Tafel slope of 65 mV·dec ^-1. The above results indicated that the MoS₂/PVP catalytic electrode had excellent catalytic activity.