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    Information & Control
    An Improved Root-MUSIC Algorithm with High Precision and Low Complexity
    SHE Li-huang, LIU Ping-fan, ZHANG Shi, XU Fang-han
    2022, 43 (4):  457-463.  DOI: 10.12068/j.issn.1005-3026.2022.04.001
    Abstract ( 1188 )   HTML ( 29)   PDF (581KB) ( 704 )  
    Aiming at the precision loss problem of most low-complexity Root-MUSIC algorithms at present, a low-complexity Root-MUSIC algorithm with precision compensation ability is studied and proposed. The algorithm reconstructs the autocorrelation matrix with Toeplitz shape according to the first row of the approximate data observation matrix obtained by finite snapshots, so that the reconstructed autocorrelation matrix has Hermitian property. After decomposing the reconstructed autocorrelation matrix, the noise subspace is obtained, the noise subspace is flipped and split, a new root-finding polynomial is reconstructed, and then the DOA estimated value is obtained by the root-finding method. The algorithm proposed in this paper using Toeplitz matrix reconstruction and root polynomial reduction effectively improves the DOA estimation accuracy of the improved Root-MUSIC algorithm. And the time complexity of the improved algorithm is no higher than that of previous algorithms. Under different incident sources and sampling snapshots, the algorithm proposed in this paper also shows stronger robustness and stability.
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    Research on Model Counting with Mixed Exactly-One Constraints
    HAN Shu-ting, LAI Yong, LIU Jie
    2022, 43 (4):  463-469.  DOI: 10.12068/j.issn.1005-3026.2022.04.002
    Abstract ( 473 )   HTML ( 2)   PDF (567KB) ( 195 )  
    Model counting is the number of models for a given proposition formula, which is a basic problem in the field of artificial intelligence. There are many exactly-one constraints in many practical problems such as Bayesian networks, bounded model detection, and accurate set coverage. A common processing method is to encode exactly-one constraints as CNF formulas, and then call the model counter to solve them. This method expands the scale of the proposition formula and easily leads to too long solution time. This paper respectively proposes the ECR algorithm that restores exactly-one constraints from the CNF formula and the ECP algorithm that handles exactly-one constraints. The ECR algorithm can significantly improve the solution efficiency of the C2D compiler. Based on the latest model counter ExactMC, this paper improves the model counter ECMC that can recognize and handle exactly-one constraints separately. The experimental results show that the time efficiency of ECMC is significantly improved compared to ExactMC.
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    Image Deraining Based on Adaptive Perceptual Pyramid Network
    YANG Ai-ping, WANG Chao-chen, WANG Jian, ZHANG Teng-fei
    2022, 43 (4):  470-479.  DOI: 10.12068/j.issn.1005-3026.2022.04.003
    Abstract ( 527 )   HTML ( 4)   PDF (4949KB) ( 219 )  
    Although deep learning-based methods have made great progresses in the field of single image deraining, existing methods still have some problems such as loss of detail and residue of rain streaks. To overcome these short-comings, this paper proposed an adaptive perceptual pyramid network to remove dense rain streaks while revising image details at the same time and thus significantly improve the visual quality. Firstly, a multi-scale pyramid network with progressive connected sub-networks is constructed based on wavelet transform to extract and remove rain streaks iteratively. Each sub-network with the adaptive rain streak perceptual block as its core module is constructed through symmetric skip-connection to extract the shallow layer features to deeper layers to be reused. The adaptive rain streak perceptual block uses non-local operation and shared dilated convolution to expand the receptive fields, which can effectively perceive and remove rain streak adaptively. In order to remove rain streaks with different scales and impose some constrains of the network training, a multi-scale loss function is designed so as to gradually remove rain streaks from coarse to fine, which can effectively prevent artifacts. Extensive experimental results on synthetic and real datasets demonstrate the superiority of the proposed method over the state-of-the-art methods, which can remove rain streaks effectively with preserving vivid image details.
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    Research on Distributed Resource Sharing Incentive Mechanism Under Cloud Manufacturing Mode
    CHEN Han-ning, HU Yong-qing, SU Wei-xing, SUN Lin-cheng
    2022, 43 (4):  480-488.  DOI: 10.12068/j.issn.1005-3026.2022.04.004
    Abstract ( 543 )   HTML ( 2)   PDF (1343KB) ( 270 )  
    In response to the urgent need for large-scale open collaboration and resource sharing between distributed enterprises under the cloud manufacturing mode, this paper combines evolutionary game theory to establish an incentive mechanism for resource sharing in a distributed environment, and analyzes the evolutionary game trend of resource sharing in different situations. It can be known through theoretical analysis and simulation experiment that total shareable resources, resource sharing level, resource utilization capacity, synergy benefit coefficient, evaluation benefit coefficient, sharing incentive coefficient and speculative penalty coefficient play positive roles in promoting the resource sharing, while the shared cost coefficient plays a negative role and direct benefit level has no effect. There is an inverted U-shaped relationship between the allocation coefficient of synergy benefit and the stable state of resource sharing evolution. This study provides references for promoting distributed resource sharing and accelerating industrial innovation in the future cloud manufacturing mode.
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    ECG P Wave Detection Combining Particle Swarms and Energy Difference Between Bilateral Long and Short Windows
    XU Li-sheng, SU Yu-jian, TAN Jun-yi, FANG Xi-dong
    2022, 43 (4):  488-495.  DOI: 10.12068/j.issn.1005-3026.2022.04.005
    Abstract ( 436 )   HTML ( 2)   PDF (1082KB) ( 102 )  
    The ECG P wave contains abundant physiological and pathological information of the human body, but the P wave amplitude is small and the shape is changeable, which is very difficult to detect. This paper proposes a bilateral long-short-window energy difference method to detect multi-modal P wave boundaries, and uses the particle swarm algorithm to optimize its parameters. 4363 and 1936 ECG beats are selected from the LUE database and QT database respectively, with 70% and 30% of them used as the training set and the test set, respectively. Compared with the parameter-mixed Gaussian fitting method based on dynamic programming and the phase-free stationary wavelet transform method, the error of the results of positive and negative P waves is significantly smaller than the above two methods, and the algorithm can detect bidirectional P waves, and it also has anti-noise ability.
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    Improved Iris Locating Algorithm Based on YOLOV3
    YU Zhe-zhou, LIU Yan, LIU Yuan-ning
    2022, 43 (4):  496-501.  DOI: 10.12068/j.issn.1005-3026.2022.04.006
    Abstract ( 488 )   HTML ( 8)   PDF (1119KB) ( 400 )  
    Aiming at the problem of inaccurate locating of traditional iris locating algorithms, an improved YOLOV3 iris locating model is proposed to improve the accuracy of iris locating and make it better applied to production practice. Using the Densenet-121 model as the feature extraction module, and on the basis of it, the auxiliary network is obtained by copying the backbone network to make it more conducive to the detection of small targets, and the non-local attention mechanism is used to enhance the semantic information of the features obtained by the image. The YOLOV3 model, Daugman model and Wilde model based on DarkNet-53 are used for comparative experiments. The experimental results show that the accuracy of the experimental model in this paper is as high as 97.1% in iris locating, which has obvious advantages compared with other iris locating models.
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    Materials & Metallurgy
    Research on Fine Characterization of Microstructure Difference of High Carbon Galvanized Steel Wire
    ZHI Wei-jun , YAO Zan, JIANG Zhou-hua
    2022, 43 (4):  501-508.  DOI: 10.12068/j.issn.1005-3026.2022.04.007
    Abstract ( 502 )   HTML ( 2)   PDF (4864KB) ( 218 )  
    The fine microstructure in high carbon galvanized steel wires from different manufacturers at domestic and abroad were experimentally characterized and compared. The results show that the microstructure of the domestic steel wires has apparently difference with that of the imported ones, in terms of the distribution of inclusion sizes, the thickness of galvanized layer, the spacing of sorbite lamella, cementite morphology, dislocation density, and etc. For instance, the percentage of the inclusions with the equivalent diameter less than 5 μm can be up to 90.6% in the imported wire, compared with 85.4% and 88.0% in the domestic ones. The Zn-Fe alloy layer in the galvanized layer of the domestic wire is thicker and the coated layer is more loose. Moreover, the sorbite lamellar spacing of the domestic wire is larger and the distribution is more dispersed. It is also found that in the domestic wire, the dissolution of cementite is more serious, the number of granular and short-rod cementite particles increase significantly, and the dislocation density is 10 times than that of the imported one. The microstructural differences above lead to the poor performance and unstable quality of the domestic steel wire.
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    Numerical Simulation of Spray Characteristics of Chromium-Free Passivation Solution for Tin Plate
    LI Shu-xian, NIU Wen-yong, HUANG Yu-di, LI Jian-ping
    2022, 43 (4):  509-516.  DOI: 10.12068/j.issn.1005-3026.2022.04.008
    Abstract ( 418 )   HTML ( 1)   PDF (2677KB) ( 110 )  
    Combining numerical simulation with computational fluid dynamics software and physical experiment, the effects of spray disc rotation speed, spacing between discs, distance between spray disc and steel strip and the number of spray discs on the particle size distribution and atomization result of spraying for steel passivation were studied. The results show that, the faster the disc speed is, the faster is the atomized droplet speed, the smaller is the size of the droplets, and the better is the atomization effect. The disc speed is selected as 6000r/min. When the distance between spray disc and steel strip is 100mm, the droplets size distribution on strip is the best. When the spacing between spraying discs changes, the droplets interference area and collision between droplets will change accordingly, and 80mm is the best spacing. The chromium-free passivation product prepared by using the selected parameters is better than the original passivation product, showing the rationality of the parameter selection.
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    Dy Thermal Diffusion Process of NdFeB Magnets and Its Coercive Force Improvement Mechanism
    LIU Fu-gang, ZHAO Dong, XIANG Ling, PEI Wen-li
    2022, 43 (4):  517-523.  DOI: 10.12068/j.issn.1005-3026.2022.04.009
    Abstract ( 608 )   HTML ( 5)   PDF (2627KB) ( 183 )  
    The commercial 35M magnet prepared from recycled materials was used as the research object, and a self-made new DyF3 coating was used to conduct thermal diffusion treatment on the magnets. The results show that the new coating has the characteristics of quick-drying, good adhesion and uniform coating, which effectively improves the stability of thermal diffusion process. The magnet subjected to thermal diffusion treatment at 920℃×10h, has a good performance on the magnetic properties, where the coercive force of the magnet reaches 1710.2kA/m with an increase of 37.9%. Microstructure analysis reveals the diffusion process of Dy element and the mechanism of coercive force improvement of the magnet. It is found that Dy element diffuses along the grain boundary and a Dy-rich shell of(Nd, Dy)2Fe14B with a higher anisotropy field can be formed around the grains of main phase, which makes the Nd-rich phase of the grain boundary more continuous and clear, resulting in a substantial increase in the coercive force of the magnet.
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    Prediction and Control of Oxygen Content in Steel During Electroslag Remelting Process
    HUANG Xue-chi, LI Bao-kuan, DUAN Yi-ru, LIU Zhong-qiu
    2022, 43 (4):  524-534.  DOI: 10.12068/j.issn.1005-3026.2022.04.010
    Abstract ( 595 )   HTML ( 2)   PDF (2624KB) ( 277 )  
    In order to reduce the total wO in electroslag remelting(ESR)ingots, a thermo-kinetic model of simultaneous reaction is established to predict the interface mass transfer rate. The oxygen transfer behavior in ESR process coupled with electromagnetic-flow-heat-mass transfer was analyzed, and the control methods for wO of molten steel were proposed. The results show that with the progress of the remelting process, both the w○FeO of the molten slag and the wO of the molten steel increase, showing the phenomenon of "deoxidation" in the early stage of remelting and "reoxidation" in the later stage. The slag pool-electrode end and slag pool-metal droplet interface are the main locations where the wO increases. As the current increases from 1200~1800 A, the wO decreases from 82.4 ×10-6 to 70.6 ×10-6. The implementation of inert gas protection can decrease the wO from 78.7 ×10-6 to 15.3 ×10-6. Using 70% CaF2+30% Al2O3 slag system to control wO of molten steel has the best effect. The slag system with low w○Al▲2O▲3 is beneficial to reduce the wO of molten steel.
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    Mechanical Engineering
    Influencing Factors of Grinding Surface Quality of TiC-Coated Micro-grinding Tools
    WEN Xue-long, LI Jia-yu, LI Xin-yan
    2022, 43 (4):  534-540.  DOI: 10.12068/j.issn.1005-3026.2022.04.011
    Abstract ( 452 )   HTML ( 2)   PDF (2785KB) ( 148 )  
    The grinding experiment of soda-lime glass was carried out to study the effects of grinding parameters on the surface roughness and morphology of the glass. The surface morphology was compared after grinded by different coated micro-grinding tools and surface roughness under different cooling conditions were also analyzed. The results show that when the grinding speed increases and the grinding depth and feed rate decrease, the surface roughness decreases and the surface morphology becomes smoother and better. Under different cooling conditions, the level of surface roughness after wet grinding is lower and the surface quality is better. In comparison with the CBN-coated micro-grinding with the same granularity, the diamond-coated micro-grinding can perform a better surface quality and more suitable for hard and brittle materials, such as glass.
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    Research on Real-Time Overload Prediction Method of in-Service Structures
    YANG Bo-wen, HUO Jun-zhou, ZHANG Wei, ZHANG Zhan-ge
    2022, 43 (4):  541-550.  DOI: 10.12068/j.issn.1005-3026.2022.04.0012
    Abstract ( 497 )   HTML ( 5)   PDF (4383KB) ( 166 )  
    In order to ensure the real-time monitoring of the fatigue life of key structures, the dynamic random load is used as the monitoring condition to accurately predict the importance of the advanced load spectrum for actual engineering analysis.Aiming at the difficulty of real-time monitoring of in-service equipment and accurately responding to the real laws of load, a probability density prediction method based on numerical analysis is proposed, combined with machine learning BP neural network intelligent algorithm to establish a prediction model. The random load is collected by the strain sensor for preprocessing to obtain random load spectra, and the Monte Carlo method is used to analyze the model load waveform trend and the prediction accuracy of the fluctuation range. The results show that the nuclear density fitting curve of the advanced prediction load spectrum has a high similarity to the real value, which provides theoretical support and practical engineering application for the advanced load monitoring of large and complex in-service structures.
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    Vibration Characteristics of Multi-layer Winding Drum of Mine Hoists
    GE Jian-bing , GONG Xian-sheng, PENG Xia, LIU Jin-jun
    2022, 43 (4):  551-559.  DOI: 10.12068/j.issn.1005-3026.2022.04.013
    Abstract ( 373 )   HTML ( 0)   PDF (1857KB) ( 75 )  
    In order to reveal the vibration characteristics of the multi-layer winding drum and the influence of relevant parameters of the mine hoisting system on its dynamic response, a double folding line drum of the mine hoist experimental platform was taken as the research object, the vibration equations with coupling terms of the drum with slowly varying mass under rope transiting excitation were established by using Lagrange equation of variable mass holonomic mechanical system. The numerical analysis and experimental verification of the model were carried out. The results showed that the deduced equation reflects the vibration characteristics of the drum well. The acceleration amplitude of the two directions of the drum is slightly different. The amplitude of vibration acceleration in both directions of the drum fluctuates and is characterized by synchronization. The effects of such system parameters as drum speed, drum asymmetric angle, center angle of the crossover arc, wire rope diameter and density on drum vibration acceleration were discussed. The research results are helpful to optimize the drum structure, and have some reference value for the safe operation of the system.
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    Resources & Civil Engineering
    Mechanism of Surface Subsidence Propagation Based on Structural Instability Characteristics of Combined Rock Strata
    YU Jian-yang, JING Hong-di, LIU Xiao-bo , SHAN Chuan
    2022, 43 (4):  559-566.  DOI: 10.12068/j.issn.1005-3026.2022.04.014
    Abstract ( 485 )   HTML ( 2)   PDF (1395KB) ( 111 )  
    By dividing the overlying strata of the stope into a number of combined rock strate, and analyzing the mechanism of surface subsidence expansion through the instability characteristics of the combined rock strate, the internal relationships between failure sequences of the beam and support of the combined rock strate, as well as the expansion of the surface subsidence were analyzed respectively. It is believed that the failure of the rear support of the combined rock strate and the subsequent slipping into the goaf is the fundamental reason for the expansion of the surface subsidence. A quantitative method for describing the collapse of the combined rock strate till to the surface subsidence process was proposed. Based on the plastic softening and damage theory of the coal and rock mass, the calculation formula for the failure width of the support body at the rear of the structure is deduced. According to the subsidence expansion mechanism and quantitative formula, the engineering example calculation of SW4102 and SW4103 working faces of Tiefa Xiaonan Mine is carried out.
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    Simulation and Parameters Optimization of Medium Deep Hole Blasting in Steeply Narrow Vein Mine Under Confinement
    AN Long, ZHANG Jia-hua, LI Yuan-hui, HAN Lin
    2022, 43 (4):  567-574.  DOI: 10.12068/j.issn.1005-3026.2022.04.015
    Abstract ( 512 )   HTML ( 0)   PDF (8143KB) ( 270 )  
    Taking the medium deep hole mining in steeply narrow vein of a gold mine in Inner Mongolia as the engineering background, through empirical analogies, numerical simulation and field tests methods, the evolution law of cracks in narrow veins of deep hole blasting under different blasting parameters was analyzed, and the relationship between the blasting parameters and the over-under-excavation percentage of blasting, the density of blasting cracks and the vibration velocity of the surrounding rock particles is obtained. The results show that: when the hole spacing is 1.2~1.4m, the over-under-excavation blasting area tends to be zero. When the burdern is 0.8~1.0m, the blasting fragmentation is more uniform. A burden of 1.0m and a hole spacing of 1.2m can be taken as optimal parameters during deep hole blasting. The field blasting test also verifies the research results of this paper.
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    Connection of Precast Profiled Steel Sheet Concrete Composite Plate and Steel Beam and Its Finite Element Analysis
    WANG Lian-guang, MENG Yu-qi, WANG Zi-qing
    2022, 43 (4):  575-581.  DOI: 10.12068/j.issn.1005-3026.2022.04.016
    Abstract ( 619 )   HTML ( 7)   PDF (1713KB) ( 191 )  
    In order to meet the load-bearing and deformation requirements of precast composite plate and steel beam connection joints, a new type of flange plate-bolt connection joint with integral precast of profiled steel sheet concrete composite plate and steel beam was proposed. The cast-in-place and precast joint models were established by using ABAQUS respectively, the stress performance of which under the same conditions was compared, and the influence of the number of studs, the thickness and length of the composite plate, the number of bolts and the thickness of the flange plate on the stress performance of the precast joint model was analyzed. The results show that the stress performance of the precast joints is similar to that of the cast-in-place joints. The precast joints with 96 studs, 8 bolts, 200mm thick, 5.1~6.6m long composite plate and 10mm thick flange plate are suggested to be used when design.
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    Experimental Study on Multi-Factor Influence Law and Energy Criterion of Coal and Gas Outburst
    WANG Wei, WANG Han-peng, ZHANG Bing, XU Fei
    2022, 43 (4):  582-590.  DOI: 10.12068/j.issn.1005-3026.2022.04.017
    Abstract ( 404 )   HTML ( 1)   PDF (3649KB) ( 241 )  
    In order to analyze the coupling influence law of multi-factors of coal and gas outburst, the outburst simulation test for rapid exposure of gas-containing coal under multiple conditions was carried out. Combining the simulation test results with the outburst energy model to calculate the quantitative relationship between outburst potential and outburst energy consumption, the results shows that the outburst critical gas pressure is positively correlated with coal strength and negatively correlated with the axial stress, which verifies the necessity of the energy criterion for outburst excitation. Based on coal elastic energy, gas expansion energy, coal strength and density and other parameters to establish two dimensionless parameters, and then fit the energy criterion formula for severe outburst. The results show that: the greater the gas pressure and axial stress, the smaller the coal strength and the higher the outburst risk. The order of importance of the influence of various factors on the risk of coal and gas outburst is: gas pressure> coal strength> axial stress.
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    Management Science
    Matching Model for Private Idle Parking Spaces and Demanders Between Dual-Role Agents
    JIANG Yan-ping, SONG Xin-chao, SHAO Xin-ran
    2022, 43 (4):  591-599.  DOI: 10.12068/j.issn.1005-3026.2022.04.018
    Abstract ( 407 )   HTML ( 4)   PDF (685KB) ( 127 )  
    Sharing economy provides a new way to solve the problem of “parking difficulty”. A matching problem between private idle parking spaces agents and demanders of dual-role agents was studied. A dual-role agent not only needs parking spaces near the destination, but also intends to share its own parking spaces. According to the acceptable price, time window and maximum allowable walking distance of the matching subjects, the regional heat priority as a supplier and demander of private parking spaces was calculated respectively. A multi-objective optimization model is constructed with the goal of maximizing platform revenue, maximizing the number of subject matches and the highest subject priority.The multi-objective optimization model was solved by the improved NSGA-II algorithm, the matching plan between private idle parking spaces and demanders was determined, and the feasibility of the proposed method was illustrated by a calculation example. The research results may provide reference for the research on matching between private parking spaces and demanders.
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    Analysis of Macroeconomic Motivations of Cross-Border Mergers and Acquisitions in China Based on EEMD Model
    XIAO Ming, GUO Ying, ZHU Jia-hui
    2022, 43 (4):  599-608.  DOI: 10.12068/j.issn.1005-3026.2022.04.019
    Abstract ( 410 )   HTML ( 5)   PDF (1533KB) ( 164 )  
    Taking the cross-border mergers and acquisitions (M&As) implemented by China’s A-share listed companies from 2008 to 2018 as a sample, the ensemble empirical mode decomposition (EEMD) model is used to examine the relationship between the macroeconomic environment and cross-border M & As from two time scales: short-term and long-term. The results show that in recent years, the sustained and high-speed development of China’s macro-economy is the main reason for the long-term fluctuations in cross-border M&As, and the rising uncertainty of domestic economic policies will also promote it. Short-term fluctuations in the stock market and economic policy adjustments are important factors driving short-term fluctuations in cross-border M&As. Regardless of the long-term and short-term scales, economic expectations have a negative inhibitory effect on the fluctuation of cross-border M&As. When the domestic stock market index is at a high level and future economic expectations deteriorate or economic policy uncertainty rises, it is more likely for Chinese companies to conduct cross-border M&As.
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