Volume 44,Issue 11,2021 Table of Contents

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  • 1  A wide locking range injection-locked frequency divider for high-speed phase-locked loop
    XING Zizhe
    2021, 44(11):1-8. DOI: 10.11835/j.issn.1000-582X.2021.11.001
    [Abstract](497) [HTML](755) [PDF 823.90 K](769)
    Abstract:
    A 30 GHz wide locking range injection-locked frequency divider based on 55 nm CMOS process for millimeter-wave phase-locked loop was proposed to overcome the problem of narrow locking range of traditional injection-locked frequency dividers. Distributed direct injection and high-order transformer resonator were applied to the frequency divider to increase the injection current and injection efficiency, thus achieving wide locking range without tuning mechanisms. Harmonic suppression technique was also adopted to the output buffer to improve the locking range with no penalty in power consumption. The post simulation results show that the locking range of the proposed frequency divider was 22.8-36.3 GHz (45.7%) at the injection power of 0 dBm and the power dissipation of core circuit was 3.54 mW.
    2  A novel magnitude and phase indirect correction technique for active baluns
    LI Shiyuan
    2021, 44(11):9-16. DOI: 10.11835/j.issn.1000-582X.2021.11.002
    [Abstract](560) [HTML](536) [PDF 503.87 K](630)
    Abstract:
    A novel magnitude and phase indirect correction technique for active baluns was proposed to solve the amplitude and phase mismatch between outputs at millimeter wave frequency. With this technique, the input gain and phase errors are equally distributed and recombined by common emitter-common base structure. In the process of distribution and combination, the unknown variable errors between the input signals were transformed into the inherent errors caused by the correction circuits so as to restrict and indirectly correct the input gain and phase errors, resulting in a new ideal differential output signal. The mathematical model and derived formulas confirmed the feasibility of the technique in ideal conditions and the simulation demonstrated the effectiveness of the circuit and validated the theoretical analysis. The simulation results show that the 3 dB bandwidth of the correction circuit was 96-113 GHz and the maximum power gain was 12.7 dB. The differential outputs had gain error less than 0.3 dB and phase error less than 5.3° when the inputs had gain error from 0 dB to 10 dB and phase error from 10° to 110° at 105 GHz. The dc power consumption was 54 mW.
    3  The application of Mel-Frequency Cepstral Coefficients technology based on fundamental frequency in vehicle recognition
    LI Chengjuan YI Qiang LI Baoqing WANG Guohui
    2021, 44(11):17-23. DOI: 10.11835/j.issn.1000-582X.2021.11.003
    [Abstract](705) [HTML](582) [PDF 1.16 M](823)
    Abstract:
    The Mel-Frequency Cepstral Coefficients(MFCC) are susceptible to noise in field vehicle recognition. To enhance the robustness of features, this paper proposed a weighted and adaptive feature extraction algorithm based on the MFCC method. Firstly, the energy to entropy ratio method was used to detect the endpoint of field vehicle's acoustic signal. Then, the fundamental frequency of vehicle's acoustic signal was extracted. The triangular filter bank was adaptively constructed according to the fundamental frequency so as to improve the filter’s sensitivity to the fundamental frequency. Finally, the obtained frequency was weighted with fisher’s ratio. Compared with the traditional MFCCs, the experimental results show that the improved MFCCs improve the recognition accuracy by 7.10%, reduce the false alarm rate by 3.93% and reduce the leakage alarm rate by 7.10% in field vehicle recognition.
    4  The application of composite differential tracker to capacitive position sensor
    WU Hao CHEN Yu
    2021, 44(11):24-30. DOI: 10.11835/j.issn.1000-582X.2021.11.004
    [Abstract](487) [HTML](1104) [PDF 1.33 M](677)
    Abstract:
    The general form of differential tracker cannot properly deal with the problems of signal tracking phase lag, noise amplification, many parameters and complicated debugging when obtaining position information and velocity signals from a capacitive position sensor containing random disturbances. Based on the equivalent linear analysis of differential trackers, a composite form of differential tracker was proposed for position signal tracking and velocity signal estimation of position capacitive sensors. The simulations and experimental tests of MATLAB \\ SIMULINK show that the composite differential tracker can approach the original smoothly and the position signal and the velocity signal can be effectively extracted. Compared with the general form differential tracker, the tracking signal phase lag and the speed signal noise can be better taken into account.
    5  Design and implementation of RISC-V microcontroller for stepper motor control
    TANG Chuan LIU Yu ZENG Lin
    2021, 44(11):31-39. DOI: 10.11835/j.issn.1000-582X.2021.11.005
    [Abstract](541) [HTML](630) [PDF 2.52 M](817)
    Abstract:
    To explore a flexible control and design scheme in the field of stepper motor control, a RISC-V microcontroller for stepper motor control was designed and developed, based on the open source innovation of the RISC-V (reduced instruction set computer-five) architecture in the hardware field. By integrating the processor, memory, peripherals and debugging interface modules into a single FPGA (field-programmable gate array) chip, the configurable microcontroller platform was constructed. By building simulation debugging environment and joint debugging of software and hardware, the correctness of microcontroller design was verified. In the test of stepper motor control system, pulse width modulation (PWM) module produced control pulses, quadrature coded pulse circuit (QEP) detected position of the rotor, the hardware system worked normally and the relative error of the experiment was controlled in the order of one thousandth.
    6  BaaS resource load balancing scheduling algorithm based on spectral clustering
    XIONG Yanjie GAO Zhen LI Gen YANG Jinsheng
    2021, 44(11):40-47. DOI: 10.11835/j.issn.1000-582X.2021.11.006
    [Abstract](504) [HTML](500) [PDF 902.01 K](705)
    Abstract:
    As one of the core frameworks of the Hyperledger, Fabric provides users with private transaction space with its multi-channel design. In order to solve the problem of multi-channel resource load balancing based on distributed architecture, a Blockchain as a Service (BaaS) load balancing scheduling algorithm SC-channel based on NJW spectral clustering was proposed. The proposed algorithm took the number of platform sub-nodes as the basis for classifying the number of clusters. Firstly, based on channel the Jaccard coefficient between peer was used to construct the similarity matrix. Secondly, the Laplacian matrix was calculated to obtain the first k eigenvalues and eigenvectors, and the eigenvectors were unitized. Finally, the feature clustering was done using the classical weight-based k-means algorithm. The proposed algorithm was validated on the Kubernetes platform and its resource balance degree was compared with those of the NJW algorithm using the classic k-means and the default scheduling algorithm. Theoretical analysis and experimental results show that the BaaS resource load balancing scheduling algorithm based on spectral clustering can improve the balance of resource utilization and enhance the usability and reliability of the platform.
    7  Server load balancing strategy using OpenFlow switch
    ZENG Youwen LI Shuangqing ZOU Dongsheng
    2021, 44(11):48-56. DOI: 10.11835/j.issn.1000-582X.2021.201
    [Abstract](586) [HTML](1093) [PDF 970.12 K](749)
    Abstract:
    Massive concurrent access to servers is very common in cloud data centers. It is difficult for traditional network architecture to control traffic forwarding globally, and expensive load balancers are needed to deal with this application scenario. The SDN(software defined network) can globally control the network status through the controller, and use the switch as a load balancer, thereby reducing deployment costs. A server load balancing strategy based on OpenFlow switches was proposed in this paper. Service requests were partitioned and mapped through multi-address directed flow table, and the number of active connections was used as a load evaluation parameter. The optimal load redirection scheme was found through ant colony algorithm. During load migration, single-address directed flow table was used to ensure orderly forwarding of traffic at different stages. Experimental results show that the proposed strategy can effectively control the size of flow table and has better performance than traditional equalization strategies.
    8  Unsupervised domain adaptive person re-identification guided by low-rank priori
    LI Lingli XIE Minghong LI Fan ZHANG Yafei LI Huafeng TAN Tingting
    2021, 44(11):57-70. DOI: 10.11835/j.issn.1000-582X.2021.11.008
    [Abstract](727) [HTML](787) [PDF 8.55 M](670)
    Abstract:
    Unsupervised domain adaptive person re-identification plays an important role in intelligent monitoring, but the domain shift among different datasets brings great challenges to person re-identification. Studies have reported that the pedestrian images captured from the same camera view have same style in continuous time. If this style information is separated from the pedestrian image, the domain shift problem caused by image style difference will be effectively alleviated. In this paper, a low rank prior guided dictionary learning scheme with domain invariant information separation was proposed. Firstly, according to the low rank priori of the style information, style information and pedestrian identity information in the pedestrian image features were separated. Secondly, according to the domain invariance of the pedestrian attributes of the same identity, the relationship between the visual features and the attributes was established to alleviate the impact of domain shift. Finally, self-training strategy was used to adjust the learning parameters. Experimental results show that the proposed method outperforms the traditional unsupervised domain adaptive person re-identification methods and some unsupervised domain adaptive person re-identification methods based on deep learning in many datasets.
    9  An encoder-decoder multi-step traffic flow prediction model based on long short-time memory network
    WANG Bowen WANG Jingsheng WANG Tongyi ZHANG Ziquan LIU Yu YU Hao
    2021, 44(11):71-80. DOI: 10.11835/j.issn.1000-582X.2021.160
    [Abstract](846) [HTML](1340) [PDF 7.78 M](920)
    Abstract:
    Most of the traffic flow sequences are single-step prediction. To realize multi-step prediction of traffic flow sequence, a long short-term memory (LSTM) model based on encoder-decoder (ED) framework was proposed. To verify the proposed encoder-decoder LSTM multi-step traffic flow prediction model (ED LSTM), autoregressive moving average, support vector regression machine, XGBOOST, recurrent neural network, convolutional neural network and LSTM were used as control groups for the experiment. Experimental results show that when the prediction time step increased, ED framework could slow down the decline of model performance, and LSTM could fully mine the nonlinear relationship in time series. In addition, under the condition of univariate input, the root mean squard error (RMSE) and mean absolute error (MAE) of ED LSTM model decreased by about 0.210-5.422 and 0.061-0.192, respectively, on PEMS-04 dataset with 12 time steps from t+1 to t+12. Compared with single-factor input, the ED LSTM model with multi-factor input decreased RMSE and MAE by about 0.840 and 0.136 respectively under 12 prediction time steps, demonstrating that ED LSTM model can be effectively applied to multi-step and single-factor and multi-factor forecasting of traffic flow series.
    10  Network intrusion detection method based on Transformer neural network model
    GUO Zhimin ZHOU Jieying WANG Dan LV Zhuo YANG Wen
    2021, 44(11):81-88. DOI: 10.11835/j.issn.1000-582X.2021.11.010
    [Abstract](1326) [HTML](2929) [PDF 1.47 M](1095)
    Abstract:
    Network intrusion detection has always been one of the key tasks in network security. Traditional network intrusion detection methods mainly use machine learning method to construct detection models by extracting multi-dimensional features, while most of them ignore the time correlation of intrusion behaviors. In this paper, a Transformer network model with multi-head self-attention mechanism based on dimension reduction feature was designed by extracting the time sequence features of network intrusion behavior. The proposed model solved the problems that traditional serial sequential neural network models are difficult to converge and have a large time consumption. The optimal loss function and training parameters were selected to implement the network intrusion detection. The experimental results show that the network intrusion detection method based on Transformer network model achieves the accuracy and the detection rate of over 99% in multiple datasets.
    11  A design method of multi-output forward converter with low crossover regulation
    CHENG Hongli TIAN Futao LI Yong
    2021, 44(11):89-100. DOI: 10.11835/j.issn.1000-582X.2021.11.011
    [Abstract](676) [HTML](971) [PDF 2.05 M](936)
    Abstract:
    The multi-output forward converter has many advantages, including simple structure, high reliability, and wide application, but there is a problem of cross regulation. To fundamentally improve the cross regulation rate, a target average current control strategy was proposed. Firstly, the real-time load was obtained by sampling the real-time voltage and real-time current of each output terminal with ARM-STM32(Acorn RISC Machine - STMicroelectronics 32). Then the target average current was calculated by combining the real-time load with the expected output voltage. According to the target average current and the hardware parameters of the multi-output forward converter, the conduction time of the main circuit switching transistor and each secondary side rectifier switching transistor was calculated. The program automatically controlled the conduction time of each switching transistor to achieve the goal that the average output current of each output circuit equals the target average current. The experimental results show that the multiple output forward converter using output average current control has a cross regulation rate of less than 1.6%. The multiple output forward converter controlled by this strategy can not only achieve a low cross regulation rate, but also has a higher voltage accuracy.
    12  Denoising of seismic signals based on non-local mean in Shearlet domain
    LI Min ZHOU Yatong LI Mengyao WENG Liyuan
    2021, 44(11):101-114. DOI: 10.11835/j.issn.1000-582X.2020.246
    [Abstract](669) [HTML](564) [PDF 5.38 M](756)
    Abstract:
    Due to the limitations of the acquisition environment and instrument performance, the collected seismic signals contain strong random noise, which presents great challenges for subsequent processing and interpretation. Multi-scale geometric analysis has attracted attention in recent years. This paper introduces non-local mean algorithm (NLM) into the Shearlet transform domain to denoise seismic signals. The algorithm firstly performs non-subsampled Shearlet transform on seismic signals, and approximates the generalized Gaussian distribution. The Shearlet coefficients are subjected to principal component analysis (PCA), and then the non-local mean processing Shearlet coefficients are used. Finally, the new Shearlet coefficients are inversely transformed by Shearlet to obtain the denoised seismic signals. The experimental results show that under low noise the proposed algorithm can achieve better denoising effect than the non-local mean algorithm. Therefore, the proposed algorithm is feasible for denoising seismic signals.

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