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15 June 2021 Volume 34 Issue 6
  
    Animal Disease Diagnosis Algorithm Based on Covering Rough Vague Soft Expert Set
    CHEN Penggang,FENG Xiaoyi
    Electronic Science and Technology. 2021, 34(6):  1-10.  doi:10.16180/j.cnki.issn1007-7820.2021.06.001
    Abstract ( 374 )   HTML ( 216 )   PDF (1020KB) ( 71 )  
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    In view of the shortcomings of the existing Vague soft set extension model, three models including covering rough set, Vague soft set and soft expert set are merged and expanded, and a new mathematical model for dealing with uncertain problems is proposed in this study, namely covering rough Vague soft expert set, and related properties are studied. On this basis, this study presents an assisted diagnosis algorithm for animal diseases based on a rough set of Vague soft experts. The algorithm calculates the upper and lower approximation operators covering the rough Vague soft expert set, establishes the relationship between the disease degree and the disease level through the membership function, and makes an auxiliary diagnosis. The diagnostic results of African swine fever disease show that the ADADA_CRVSES algorithm proposed in the study is an effective auxiliary diagnosis algorithm for animal diseases, and the accuracy rate of disease diagnosis is more than 90%.

    Staging Diagnosis of Liver Fibrosis Based on Transfer Learning Strategy
    ZHAI Yuexian,LIU Xiang,SONG Jialin
    Electronic Science and Technology. 2021, 34(6):  11-16.  doi:10.16180/j.cnki.issn1007-7820.2021.06.002
    Abstract ( 221 )   HTML ( 17 )   PDF (1197KB) ( 40 )  
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    In view of the problem that the accuracy of classification of liver fibrosis into four stages is low, and the difficulties in distinguishing S2 and S3 stages, a method of liver fibrosis’s diagnosis based on transfer learning strategy is proposed in this study. This method is based on a pre-trained deep residual network model, randomly initializes the weight parameters of each layer, and adds a dataset expanded by the method of rotation and cutting patch blocks to fine-tune various parameters. After the softmax classifier combined with the patch block voting principle, the accuracy rates of liver fibrosis S0~S1S2S3 and S4 stages are 93.75%、90.63%、87.50% and 86.96%, respectively. The proposed method achieves good results in the quantitative diagnosis of liver fibrosis based on high-frequency ultrasound images. The comparative analysis reveales that this method is superior to other existing methods, and provides a more effective solution for clinical computer-aided diagnosis of liver fibrosis diseases.

    Simulation Analysis of Induced Current Density of Transcranial Magnetic-Acoustical Electrical Stimulation Based on Realistic Human Head Model
    LIU Yaze,ZHANG Shuai,GUO Liang,CHEN Xintong,WU Jiankang
    Electronic Science and Technology. 2021, 34(6):  17-22.  doi:10.16180/j.cnki.issn1007-7820.2021.06.003
    Abstract ( 386 )   HTML ( 23 )   PDF (1239KB) ( 61 )  
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    The focusing characteristics of the induced current density is the key to precise neural regulation. The structure of the skull has an important influence on the induced current density distribution of TMAES. Therefore, a realistic human head model based on the CT data of the human head is established using the 3D calculating method. The finite element method is used to simulate the model during TMAES. The distribution of induced current density is obtained and subsequently evaluated. In order to further explore the relationship between the stimulus effect and the ultrasound frequency, ultrasonic waves with frequencies of 300 kHz, 400 kHz and 500 kHz are applied on the realistic human head model during TMAES. The results show that the increase of the frequency of the ultrasonic signal can increase the stimulation intensity, the stimulation length and the focus area. These results indicate that TMAES has good depth stimulation and focusing characteristics, and has the potential to noninvasively modulate neurons deep in the brain.

    A Vital Sign Detection Radar Based on Complex Signal Demodulation
    TAI Fanbin,LIU Yun,ZHOU Wen,HANG Xuelian,QIAN Zhicheng,LIU Jixuan,WANG Xingshuai,MA Jiaju
    Electronic Science and Technology. 2021, 34(6):  23-27.  doi:10.16180/j.cnki.issn1007-7820.2021.06.004
    Abstract ( 311 )   HTML ( 18 )   PDF (809KB) ( 43 )  
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    The radar sensor system has a good prospect in the detection of vital signs of special objects such as infants and burned patients for its advantages of non-contact, concealment and all-weather measurement. In this paper, a design of Doppler radar system based on complex signal demodulation is proposed for the effect of null point issue and the dc offset. The complex signal consisted of the two baseband signals output from the zero-IF quadrature demodulation structure is performed fast Fourier transform to obtain the vital sign of the object. The test shows that when the system works at the center frequency of 2.45 GHz, the frequency of respiration and heartbeat are respectively about 0.3 Hz and 1.1 Hz, which meet the design expectation.

    Research on the Defect Method of Detection Circular Ceramic Metal Coating
    MA Ding,WU Dingxiang,TANG Lijun
    Electronic Science and Technology. 2021, 34(6):  28-33.  doi:10.16180/j.cnki.issn1007-7820.2021.06.005
    Abstract ( 214 )   HTML ( 15 )   PDF (1741KB) ( 21 )  
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    In view of the problems in the surface inspection of annular devices, the current study takes the annular metal-coated ceramics as the research object and proposes a surface inspection method based on machine vision. The proposed method uses Canny edge detection and Hough transform to quickly locate concentric circles, and then extracts metal-coated areas. In order to convert polar coordinates to rectangular coordinates, the radial projection method is used to convert the ring-shaped metal coating map to a rectangular shape. Finally, the area and perimeter of the connected domain are analyzed to determine whether the circular ceramic metal coating has defects. The experimental results show that the detection accuracy of the algorithm is 98% for samples with a defect area greater than 0.5 mm×0.5 mm.

    Dual-Exposure Fusion Algorithm for Low-Light Image Enhancement
    LIU Tingting,ZHANG Yujin,XIONG Shiting
    Electronic Science and Technology. 2021, 34(6):  34-39.  doi:10.16180/j.cnki.issn1007-7820.2021.06.006
    Abstract ( 335 )   HTML ( 23 )   PDF (1617KB) ( 53 )  
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    Image enhancement techniques can improve the visibility of low-light image effectively. In view of the problem of over-enhancement and under-enhancement of contrast introduced by existing image enhancement methods, a dual-exposure fusion algorithm for low-light image enhancement is proposed. The weight matrix of image fusion is obtained by the illumination estimation techniques. The dual-exposure image is synthesized by the camera response model. The best exposure ratio is identified so that the synthetic image is well-exposed in the regions where the original image is under-exposed. The enhanced result is obtained by fusing the input image and the synthetic image according to the weight matrix. The scene illumination map of low illuminated pixels is reflected differently in different channels. In order to avoid the inaccuracy of brightness component caused by too large difference, the low illuminated pixels and brightness component are defined to calculate the optimal exposure ratio. Experiments show that compared with the existing methods, the proposed method has less brightness distortion and running time.

    Study on the Consistency of Electric Field Sensors in Arrays
    YU Yangyang,SUN Dongming,LI Peng,ZHOU Nianrong
    Electronic Science and Technology. 2021, 34(6):  40-44.  doi:10.16180/j.cnki.issn1007-7820.2021.06.007
    Abstract ( 209 )   HTML ( 15 )   PDF (1347KB) ( 17 )  
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    Array electric field sensors that work in an electric field produce interference with each other, affecting the accuracy of electric field measurement. The traditional solution is to increase the sensor spacing, but not in limited space. In view of this problem, an electric field sensor with shielding ring is proposed, which can reduce the interference between sensors, thus improving the consistency of the sensor. First, by simulating the two sensors with shielded rings under the uniform electric field, the difference between the average field strength of the upper plate is obtained, and then the sensor is changed to the sensor without the shielding ring in the equal area. The simulation results show that the sensor consistency with shielded ring is higher than that without the shielding ring. By changing the width of the shield ring from 1~6 mm simulation, the shield ring width with the highest sensor consistency is 5 mm. According to the simulation results, the sensor is made by PCB process, and the conditioning circuit is designed. Finally, the sensor is calibrated to obtain a higher sensitivity of 43.215 mV/kV·m-1, and a fitting degree of 0.999 1.

    Angle Disambiguation Algorithm for Distributed Sub-Array Antennas Radar Based on Adaptive Spatial Selection Filter
    JIANG Jie
    Electronic Science and Technology. 2021, 34(6):  45-49.  doi:10.16180/j.cnki.issn1007-7820.2021.06.008
    Abstract ( 193 )   HTML ( 17 )   PDF (1036KB) ( 39 )  
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    Distributed sub-array radar has been widely used in the integrated weapon platform. In order to solve the problem of target angle ambiguity caused by the main beam of long baseline distributed sub-array radar, an adaptive and differential beam spatial selective filtering method is proposed. In this method, the spatial filter is constructed by the sum and difference signals of the separated single array to optimize the receiving pattern. On the premise of effectively suppressing the gate lobe, the robustness of the main lobe power and the beam width of the receiving beam are guaranteed, the angle fuzzy suppression is realized, and the accurate estimation of the target angle is guaranteed. The results show that the proposed method can effectively suppress the grating lobe and ensure the accuracy of parameter estimation in tracking, thus improving the continuity and stability of the distributed array radar in target tracking.

    Research on Ship Target Recognition Method of Narrowband Radar
    ZHANG Pengfei,WEI Cunwei,LIU Xiankang,LIU Anran,YANG Ou,LIN Yonglin
    Electronic Science and Technology. 2021, 34(6):  50-55.  doi:10.16180/j.cnki.issn1007-7820.2021.06.009
    Abstract ( 184 )   HTML ( 17 )   PDF (716KB) ( 37 )  
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    A ship target recognition method based on narrowband radar is proposed in the present study. This method extracts the region of interest of the target from the echo signal of narrowband radar, then extracts the characteristics of expectation, standard deviation, variance and central moment of the target based on the region of interest. According to the track information of the radar ship target, the proposed method extracts the attitude angle of the target and introduces the attitude angle as the feature into the classifier. Finally, the narrowband radar ship target is classified using the support vector machine. The results show that the method has a high recognition rate for large, medium and small ship classification, and it has a certain engineering application value.

    Effect of Leakage Voltage on On-Resistance and Threshold Voltage of P-GaN HEMT
    LIU Xi,YE Xingning
    Electronic Science and Technology. 2021, 34(6):  56-60.  doi:10.16180/j.cnki.issn1007-7820.2021.06.010
    Abstract ( 503 )   HTML ( 15 )   PDF (1905KB) ( 62 )  
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    In order to study the influence of drain bias on the reliability of P-GaN devices, the drain stress tests of P-GaN commercial devices is conducted. By changing the drain stress bias voltage and bias time, the on resistance and threshold voltage of GaN device are observed and recorded. The test results show that the on resistance of devices without P-GaN drain structure increases first and then decreases with the change of drain voltage, while the threshold voltage is almost unaffected. The on resistance of devices with P-GaN drain structure is almost unaffected, while the threshold voltage decreases first and then increases with the change of drain voltage. In addition, through the test of different pressurization time, it is found that with the increase of time, the device without P-GaN drain structure has obvious degradation, and the device with P-GaN drain structure has relatively stable performance. The reliability of commercial GaN devices with different structures is affected by the change of drain bias conditions,and the appropriate devices should be selected according to the application conditions.

    Electromagnetic Simulation Analysis of Asynchronous Motor Starting
    FANG Xin,WU Yaohui,SONG He
    Electronic Science and Technology. 2021, 34(6):  61-66.  doi:10.16180/j.cnki.issn1007-7820.2021.06.011
    Abstract ( 346 )   HTML ( 20 )   PDF (1849KB) ( 34 )  
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    In view of the calculation of starting characteristics of small asynchronous motor in different starting modes,the two-dimensional electromagnetic model is constructed based on the finite element method to simulate the starting characteristics of the motor. Considering the effect of the motor end on the overall electromagnetic simulation in the two-dimensional model, the parameterization of the resistance and leakage inductance of the stator and rotor end are equivalently processed to the model by the method of field circuit combination. The power models of direct starting, Y-△ step-down starting and constant frequency voltage ratio starting are established by MagNet and Simulink software according to the starting circuit structure. The starting time, starting current and starting speed of the motor under different starting modes are compared and analyzed. The results show that the model can accurately simulate the characteristics of asynchronous motors under common starting methods.

    Maximizing the Cumulative Charging Utility of Wireless Sensor Networks Based on Directional Charging Model
    ZHANG Hao,WANG Ran
    Electronic Science and Technology. 2021, 34(6):  67-72.  doi:10.16180/j.cnki.issn1007-7820.2021.06.012
    Abstract ( 174 )   HTML ( 11 )   PDF (994KB) ( 25 )  
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    Under the condition of guaranteeing the permanent operation of the wireless chargeable sensor, based on the directional charging model, the optimal scheduling problem to maximize the cumulative charging utility of wireless sensor networks is studied. Approximation algorithms for selecting the docking spots and planning the moving path for mobile chargers are proposed to solve this problem, the direction selection algorithm based on maximizing charging coverage utility selects the best charging direction for charging mobile. The docking spots selection algorithm based on maximizing the sum of charging coverage utility selects the docking spots for charging mobile. The path planning algorithm based on TSP plans the moving path for mobile chargers. By comparing the effects of different factors through simulation experiments, the experimental results show that compared with omnidirectional charging, the proposed charging strategy can improve the cumulative charging utility of wireless sensor networks by 10%~60% under different network sizes and sensing densities.

    Redundant Network of Underground Power Monitoring System Based on EtherCAT
    LIU Jingyan,WANG Yumei
    Electronic Science and Technology. 2021, 34(6):  73-78.  doi:10.16180/j.cnki.issn1007-7820.2021.06.013
    Abstract ( 357 )   HTML ( 11 )   PDF (2647KB) ( 25 )  
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    In view of the problem that the reliability and maintainability of the coal mine underground monitoring system are reduced when emergency occurs, a redundant network of the coal mine underground monitoring system based on industrial Ethernet EtherCAT communication is proposed in the present study. By studying the composition, working principle and message structure of industrial Ethernet EtherCAT, the characteristics of EtherCAT communication network with or without redundant structure are compared. The link redundancy mechanism is added to the regular EtherCAT master driver. The redundant frame propagation mechanism, fault point location and recovery strategy in network port fault, link fault and node fault are planned, respectively. Under laboratory conditions, a simulation test platform for the underground power monitoring system is established based on the EtherCAT communication network and the underground coal mine power supply network, and a redundant mechanism is added to test its performance. The results show that the system has superior performance and the reliability of the system is markedly improved.

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