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    Information & Control
    An Adaptive Density Peak Clustering Algorithm
    MA Shu-hua, YOU Hai-rong, TANG Liang, HE Ping
    2022, 43 (6):  761-768.  DOI: 10.12068/j.issn.1005-3026.2022.06.001
    Abstract ( 707 )   HTML ( 13)   PDF (2772KB) ( 382 )  
    The density peak clustering algorithm cannot adaptively cluster because it cannot adaptively select the clustering center and cutoff distance dc according to data set, so that an adaptive density peak clustering(ADPC) algorithm was proposed. Firstly, a parameter μi that comprehensively considers the local density ρi and cutoff distance δi was proposed, and the cluster center was automatically determined according to the sorting and downtrend of μi. Then, an adaptive selection of dc was made based on the concept of Gini coefficient. Finally, the ADPC algorithm was verified and compared with the DPC and K-means algorithm. The experimental results show that the ADPC algorithm has higher ARI, NMI and AC values, and has a better clustering effect.
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    Channel Estimation Algorithm of OFDM System Based on GSA-BP Neural Network
    JI Ce, ZHANG Xiao
    2022, 43 (6):  769-775.  DOI: 10.12068/j.issn.1005-3026.2022.06.002
    Abstract ( 458 )   HTML ( 13)   PDF (608KB) ( 178 )  
    The nonlinear noise problem in orthogonal frequency division multiplexing(OFDM)system cannot be ignored. In order to understand the channel characteristics better, channel state information is needed by channel estimation. A channel estimation algorithm for OFDM system was proposed based on golden sine algorithm optimized BP neural network(GSA-BP). The problem was overcome that the traditional BP neural network algorithm is easy to fall into local extremum, and the estimation accuracy of channel estimation algorithm was improved. Firstly, the initial estimation of the channel was obtained through the LS channel estimation algorithm. Then, the accurate estimation of channel was obtained by using GSA-BP neural network. Simulation results show that the proposed algorithm has better performance than LS algorithm, and is close to MMSE algorithm, but it does not need channel prior statistics and is easy to implement.
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    A Transfer Learning Algorithm Applied to Human Activity Recognition
    ZHAO Hai, CHEN Jia-wei, SHI Han, WANG Xiang
    2022, 43 (6):  776-782.  DOI: 10.12068/j.issn.1005-3026.2022.06.003
    Abstract ( 442 )   HTML ( 8)   PDF (558KB) ( 177 )  
    Collecting wearable motion sensor signals and using transfer learning to overcome the inconsistency of data distribution to identify the daily behavior of the human body are very popular technologies. Using wearable sensors to collect signals will result in generating noise samples that affect the transfer effect. Traditional algorithms lack the processing of these samples. To solve this problem, the traditional algorithm was improved by introducing a sample screening algorithm based on Mahalanobis distance, and a transfer learning algorithm T-WMD was proposed that can be used for human activity recognition. And compared with other five algorithms on two public human activity recognition data sets, the results show that the algorithm proposed in this paper can effectively improve the effect of transfer learning.
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    High Perceptual Image Compression Based on Conditional GAN
    ZHANG Xue-feng, XU Hua-wen, YANG Mian-zimei
    2022, 43 (6):  783-791.  DOI: 10.12068/j.issn.1005-3026.2022.06.004
    Abstract ( 523 )   HTML ( 7)   PDF (2226KB) ( 291 )  
    A conditional generative adversarial network-based high perceptual image compression(HPIC) model was proposed to obtain a compressed image that conforms to human visual perception. In HPIC, the original image was encoded and quantized based on a hyper prior probability model. A generator based on the conditional additional label and residual module was used for the reconstruction of the compressed image, and a discriminator based on the convolutional neural network was used to distinguish the difference between the compressed image and the real image. Based on the bit rate-distortion-perception optimization theory to design the loss function, the perceptual distortion metric was chosen based on the eigenvalues of the pre-trained inception network to achieve image compression reconstruction with high perceptual quality on the one hand, and use the adversarial generation network loss to eliminate compression artifacts and improve the compression accuracy on the other hand. The experimental results show that HPIC achieves a good balance in the bit rate-distortion-perception tradeoff and outperforms the current common algorithms in all perceptual metrics scores, even though the latter uses twice as much bit rate as ours. HPIC can achieve compression with high perceptual quality.
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    Two-Stage U-Net Coronary Artery Segmentation Based on CTA Images
    WANG Lu, YANG Xiao-fan, WANG Qian-jin, XU Li-sheng
    2022, 43 (6):  792-800.  DOI: 10.12068/j.issn.1005-3026.2022.06.005
    Abstract ( 1295 )   HTML ( 42)   PDF (1747KB) ( 508 )  
    There are many challenges in coronary artery segmentation based on CT angiography(computed tomography angiography)images, such as the complex structure of the coronary artery, the severely unbalanced distribution of the coronary artery and the background, and the susceptibility to interference from the coronary veins and other tissues during segmentation. A two-stage coronary artery segmentation method was proposed. In the first stage, the 3D DRU-Net with dense feature extraction and residual feature correction capabilities was used to ensure the segmentation recall rate. In the second stage, a 2D dual encoding multi-feature fusion U-Net(2D DEMFU-Net)was developed to perform fine segmentation, in which features were extracted from the original image slices and the segmentation results produced by the first stage respectively, and the multi-level semantic features from these two branches were fused using dense skip connections, further improving the accuracy of segmentation. Experimental results show that the proposed two-stage segmentation algorithm outperforms 3D U-Net by 3.83%, 5.31% and 2.23% in terms of Dice similarity coefficient, recall rate and precision, respectively.
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    Materials & Metallurgy
    Experimental and Simulation Study on Deep Drawing of Square Box Made from Tailor Rolled Blank
    ZHANG Si-jia, HU Xian-lei, LIU Xiang-hua
    2022, 43 (6):  801-808.  DOI: 10.12068/j.issn.1005-3026.2022.06.006
    Abstract ( 621 )   HTML ( 3)   PDF (9773KB) ( 229 )  
    The microstructure and mechanical properties of different parts in tailor rolled blanks(TRBs)were studied and the differentiation was explained. A finite element model was established to simulate deep drawing process of the square box from TRB and the effects of the thickness and non-uniformly distributed mechanical properties on the model setup were discussed. After comparison the experimental and simulation results, the reliability of the numerical model was verified. Taking the limit drawing height and the offset of thickness transition zone(TTZ)as the evaluation criteria, the effects of the geometric parameters(i.e. the length and position of the TTZ, and the thickness difference between the thin and thick area)on the formability of TRB were analyzed. The results show that when the TTZ length is longer, the distance between the TTZ and thin area is smaller and the thickness difference between thin and thick areas is smaller, the formability of TRB is better. Therefore, determining the geometric parameters of TRB need to consider the formability and light-weight effect.
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    Diagnosis of Quality Defects in Hot Strip Rolled Products Based on Factor Analysis
    PENG Wen, XIN Hong-san, LI Xu-dong, SUN Jie
    2022, 43 (6):  809-814.  DOI: 10.12068/j.issn.1005-3026.2022.06.007
    Abstract ( 509 )   HTML ( 4)   PDF (672KB) ( 133 )  
    In hot strip rolling process, the relationship between production quality and influencing factors remains unclear, which greatly affects the traceability of product quality defects and subsequent improvement of product quality. Factor analysis(FA)method is introduced to the quality diagnosis. Taking the width quality defects in the threading process as an example, GT2 statistics are used to monitor the production process and the factor scores are used to characterize the parameters in production process. After obtaining the influencing degree of the width quality index and the contribution rate of each factor to the width defect, the defining reason of the width defect is finally realized. The results in-practice show that the correction of the key processing parameters based on the FA diagnosis can improve the width-control accuracy effectively, which guarantees the stability of production process and the improvement of product quality.
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    Study on Plate Angular Rolling Process Using Pattern Prediction Model
    JIAO Zhi-jie, WANG Zhi-qiang, LUO Jun-yi, XU Zhi-peng
    2022, 43 (6):  815-820.  DOI: 10.12068/j.issn.1005-3026.2022.06.008
    Abstract ( 367 )   HTML ( 7)   PDF (828KB) ( 91 )  
    The steel plate with large weight or small aspect ratio can be produced by angular rolling technology, which overcome the disadvantage of equipment limitation or low production efficiency derived from multiple turnings. Based on the principle of constant volume and the relationship of trigonometric function, the formula for the pattern and dimension change of the plate are deduced and the relationship between the turning angle and reduction for making the plate rectangular is obtained. A model for predicting the angle, reduction and width spread in angular rolling process is established. The program procedure of pattern prediction for angular rolling process is designed, the width spread calculation is simplified, and a program for angular rolling pattern prediction is developed. The pattern prediction model is verified by the angular rolling experiment. The maximum error between the calculated dimension data and actual rolling dimension data is 6.22 %, which proves that the accuracy of the pattern prediction model for angular rolling process.
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    Simulation Study on the Effect of Venturi Pyrolysis Reactor Structure on Flow Field
    LYU Chao, SUN Ming-he, YIN Hong-xin, LIU Fang
    2022, 43 (6):  821-826.  DOI: 10.12068/j.issn.1005-3026.2022.06.009
    Abstract ( 566 )   HTML ( 8)   PDF (916KB) ( 163 )  
    Due to uneven particle size in cerium oxide products prepared by Venturi pyrolysis reactor, it is necessary to optimize the structure of Venturi pyrolysis reactor to further strengthen the gas-solid mixing effect and the suction effect while improve the particle size distribution. The pyrolysis process of cerium chloride in Venturi reactor with nine different structures was studied by Euler-Euler multiphase flow and standard k-ε model with Fluent19.0 software. The gas-solid mixing and suction effect in Venturi reactor were analyzed. The results showed that the gas-solid mixing effect is best when the length of drainage tube is 35mm. The best suction capacity is obtained when the length of the drainage tube is 45mm. The gas-solid mixing effect is the best if the length of the throat tube is 150mm. The best suction capacity is achieved when the length of the throat tube is 100mm. When the ratio of diameter of expansion section to diameter of contraction section is 2∶2, the gas-solid mixing effect is the best, and the suction capacity is the best.
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    Construction and Optimization of CCHP System Coupled with LNG Pressure Energy
    FENG Ming-jie, WANG Deng-liang, ZHAO Mei-yu, ZHOU Le
    2022, 43 (6):  827-834.  DOI: 10.12068/j.issn.1005-3026.2022.06.010
    Abstract ( 392 )   HTML ( 4)   PDF (1299KB) ( 97 )  
    A novel type of combined cooling,heating and power(CCHP)system coupled with LNG pressure energy has been proposed. Taking an industrial park in Xi ′an as the research object, an optimization model with the objective of economic optimization was established by using simplex algorithm. In addition, some parameters, such as energy efficiency, exergy efficiency and CO2 emission per unit output value were taken as evaluation indexes to comprehensively evaluate the new system, and the influence of feed-in tariff on the output of various equipment and system performance was analyzed. The performance of the novel CCHP system was compared with that of conventional CCHP system, and the CO2 emission per unit output value and annual cost of the system were reduced by 29.82g/(kW·h) and 2.9×106 CNY, respectively. Primary energy utilization and exergy efficiency increased by 4.05% and 0.44%, respectively.
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    Coupling Effects of Thermodynamics in Co-precipitation on Electrochemical Performance of Cathode Materials
    ZHAO He, GAO Xuan-wen , LI Jian-zhong , DING Xue-yong
    2022, 43 (6):  835-843.  DOI: 10.12068/j.issn.1005-3026.2022.06.011
    Abstract ( 526 )   HTML ( 8)   PDF (2085KB) ( 174 )  
    The sodium ion layered oxide cathode material NaNi0.4Mn0.4Fe0.2O2 was synthesized by the co-precipitation method, and Al3+was used to effectively control and balance the co-precipitation reaction process. The thermodynamic coupling effect brought by the addition of Al element and its influence on electrochemical performance of cathode materials were investigated. In an environment where Mn2+, Ni2+ and Fe3+ ions coexist, owing to the thermodynamic coupling effect, the superior high supersaturation of Al3+ and the more negative change in the Gibbs free energy(ΔG)can efficiently changes the precipitation driving force between the solution ions, accelerating the precipitation of Ni2+and Mn2+ ions and inhibiting the precipitation of Fe3+ ions. The obtained Na[Ni0.4Mn0.4Fe0.20.995Al0.005O2 cathode material has demonstrated excellent electrochemical performance which can be attributed to the high quality precursor([0.4MnCO3·0.4NiCO3·0.2Fe(OH)30.995·0.005Al(OH)3) brought about by the introduction of Al3+.
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    Effect of Residual Gas Collection System on the Emission of Fugitive Emission Gas
    LI Xue-jiao, YANG Hong-ying, HU Hong-sheng, SONG Hai-chen
    2022, 43 (6):  844-849.  DOI: 10.12068/j.issn.1005-3026.2022.06.012
    Abstract ( 412 )   HTML ( 4)   PDF (1385KB) ( 95 )  
    Fugitive emission during residual anode cooling is the main way for aluminum electrolytic HF entering the atmosphere. In response to this problem, a residual gas collection system was developed. Besides, the residual temperature, HF emission and the fugitive emission reduction effect of the system were studied under different gas flow rates. The results show that the residual gas collection system can reduce HF fugitive emission effectively. The initial temperature of the residual anode is 920℃. The temperature drops quickly and then slowly. The HF concentration increases with the increase of the flue gas flow, and decreases with the decrease of the flue gas temperature. Correlation analysis is carried out through the fitting function. After 4h, the cumulative HF emission reaches more than 95% of the total emission. HF fugitive emission is reduced by 0.201kg/t at the optimal gas flow rate(4000m3/h), compared with no HF emission reduction measures.
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    Mechanical Engineering
    Influence of Friction Parameters on Vibration Characteristics of Piezoelectric Actuator
    WANG Peng, SUN Zhi-li, WU Nan, LUO Hai-tao
    2022, 43 (6):  850-856.  DOI: 10.12068/j.issn.1005-3026.2022.06.013
    Abstract ( 308 )   HTML ( 3)   PDF (1902KB) ( 97 )  
    A friction vibration model considering kinematics and vibration solution was proposed, and the vibration response of a piezoelectric actuator under friction force from a moving object was solved by the iterative method. The influences of the moving object velocity v, normal pressure FN, delay rate of relative sliding velocity control coefficient C, static friction coefficient μS and its lower limit μD,damping ratio ξ on the dynamic friction force and vibration characteristics were studied by numerical simulation and parameter analysis. The results showed that the amplitude of the piezo electric stack increases with the rise of FN, v, μS and C, and decreases with the increase of μD and ξ.FN and μS affect the maximum static friction, μD affects the sliding friction, v and C obviously affect the transformation between the sticking and sliding friction status and the friction force variation during the conversion of friction status.
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    Effect of Deposition Time on the Surface Properties of Vacuum Ion Plating TiC Coated Micro-grinding Tools
    WEN Xue-long, HAN Feng-bing, GONG Ya-dong, HUANG Xiong-jun
    2022, 43 (6):  857-863.  DOI: 10.12068/j.issn.1005-3026.2022.06.014
    Abstract ( 376 )   HTML ( 3)   PDF (2053KB) ( 148 )  
    The vacuum arc ion plating method is utilized to conduct experimental research on the preparation of micro-grinding tools surface coatings, and the single factor experiment is conducted to prepare the coating at different deposition time. The phase composition of the coating at different deposition time is analyzed, the effect of different deposition time on the surface morphology of the coating is studied, the changes in friction coefficient and roughness, as well as the effect on the thickness of the coating are discussed, and the reasonable deposition time is selected to prepare coated micro-grinding tools. The experimental results show that the interface reaction between the titanium coating and the diamond forms a stable titanium carbide layer, and as the deposition time increases, the friction coefficient continues to increase, and the roughness gradually decreases, and the coating thickness gradually increases. The research results provide a theoretical reference and experimental basis for the preparation and improvement of wear resistance and service life of coated micro-grinding tools.
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    Fatigue Life Assessment of a Vehicle Steering Knuckle and Probability Distribution of Its Local Crack Size
    ZHOU Yi-fu, LI He
    2022, 43 (6):  864-871.  DOI: 10.12068/j.issn.1005-3026.2022.06.015
    Abstract ( 386 )   HTML ( 2)   PDF (2509KB) ( 143 )  
    The steering knuckle is used to transfer and bear the front load of the vehicle, support and drive the front wheel to rotate around the kingpin to make the automotive turn. Aimed at the fatigue failure of a McPherson-type steering knuckle which is still at the development stage, a method is proposed to evaluate the rig test results based on its actual connection situation in the system, and the fatigue rig test is carried out under multiple working conditions. The failure cycle number distribution of the steering knuckle is evaluated by using Weibull distribution theory and N50% and N90% criteria. At the same time, a probability distribution prediction model of local fatigue crack size is derived, and the applicability of the proposed prediction model is verified by the experimental data.
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    Analysis on the Walking Ability of Dual-arm Inspection Robots Along Catenary Lines with Posture Changes
    LI Xiao-peng, LI Kai, FAN Xing, ZHANG Ling-yue
    2022, 43 (6):  872-880.  DOI: 10.12068/j.issn.1005-3026.2022.06.016
    Abstract ( 461 )   HTML ( 10)   PDF (2423KB) ( 135 )  
    A dual-arm inspection robot walking along catenary lines has such problems as the uneven force of the robot’s wheels and slipping on the lines, an active adjustment method of the moving joints is proposed to solve these problems. The force models of the robot walking wheels are established respectively, which are the traditional dual-arm inspection robot, the dual-arm inspection robot with flexible cables and the dual-arm inspection robot with moving joints. The comparative analysis shows that when the robot is in the best position and posture, the walking wheels have the best stress, and the robot is not likely to slip. The dynamic model of the inspection robot’s joint changes is established and the joint controller is designed. Simulations are carried out on two working conditions of obstacle crossing and line walking. The designed controller can assist the robot to complete the tasks of obstacle crossing and large-slope cruise. The application of the controller can effectively handle the joint vibration problem and shorten the response time. Finally, experiments of robot walking over obstacles and walking on different slopes are carried out. The results show that the designed controller can assist the robot to complete the inspection task and handle the walking slip problem.
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    Numerical Simulation Study of Stress Fields in the Additive Manufacturing and Micro-forging Process
    REN Zhao-hui, WANG Yun-he, LI Zhu-hong, WANG Chen
    2022, 43 (6):  881-887.  DOI: 10.12068/j.issn.1005-3026.2022.06.017
    Abstract ( 447 )   HTML ( 4)   PDF (1763KB) ( 128 )  
    In the laser fuse additive manufacturing process, the residual stress of the cladding layer is disadvantageous to the surface strength because of the rapid heating and cooling of the material, and the additive manufacturing-micro-forging processing technology can improve the processing quality of laser fuse additives, mechanical properties and microstructures. TC4 is taken as the research object, and the material surface is improved and strengthened by high frequency impact and rolling on the surface of the cladding layer through the feeding movement of the ultrasonic micro-forging tool head and molten pool at a certain relative distance. A model is established to conduct the numerical simulation study on the sequential thermal structure coupling of the additive and micro-forging process, and analyze the variation of the stress field of the cladding layer during the processing. The results show that the residual tensile stress of the cladding layer due to heat source loading is transformed into beneficial residual compressive stress by ultrasonic micro-forging on the surface of the uncooled cladding layer, and the probability of surface defects is reduced. The parameters of ultrasonic amplitude, feed rate and forging temperature have great influence on the residual compressive stress and normal deformation.
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    Resources & Civil Engineering
    Identification and Grouping Method of Strike Information of Rock Mass Based on the HDBSCAN Algorithm
    WANG Shu-hong, WEI Wei, CHEN Hao, YIN Hong
    2022, 43 (6):  888-896.  DOI: 10.12068/j.issn.1005-3026.2022.06.018
    Abstract ( 529 )   HTML ( 10)   PDF (7903KB) ( 293 )  
    Accurate acquisition of the strike information of the rock discontinuities is the first and key step in rock stability analysis. To solve the problems of insufficient clustering criteria and strong parameter sensitivity of the basic DBSCAN algorithm in processing the point cloud data, the HDBSCAN algorithm was proposed to extend the clustering criteria based on additional attributes of point clouds to improve the accuracy and robustness of the clustering algorithm. Meanwhile, based on the color and density attributes of the point cloud, the segmentation and extraction of the studied area of non-fully exposed rock in natural state were realized and the influence of the point cloud at non-rock structural planes on the identification and grouping of rock discontinuities production was reduced. The method was applied to a typical overburden rock slope of Dashidong tuff mine, and the results show that the method proposed can effectively eliminate non-target point cloud data, while the maximum relative error is less than 0.59% compared with the manual method, the method of rock discontinuities strike extraction and grouping are satisfactory and has practical engineering value.
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    Parameter Inversion Method of Close Multi-coalseam Based on Time Series InSAR
    LIU Cui-zhi, WANG Xing-jie, HE Li-ming, TANG Yong-liang
    2022, 43 (6):  897-904.  DOI: 10.12068/j.issn.1005-3026.2022.06.019
    Abstract ( 369 )   HTML ( 6)   PDF (5803KB) ( 214 )  
    Ground subsidence caused by close multi-coalseam mining occupies a large proportion in current mining activities. Due to the significant advantages of space-based InSAR technique in large-scale deformation monitoring, the subsidence caused by the close multi-coalseam mining in Kangping coalfield was monitored based on the 43 scenes C-band Sentinel-1B SAR data from January 2018 to August 2019. Considering the distribution characteristics of the close multi-coalseam, a close multi-coalseam parameter inversion method using superposition theory based on multi-source Okada model was proposed. By quantitatively calculating the accuracy of inversion results of dual-source model and three-source model of close multi-coalseam in elastic half space, it is found that the three-source model has a higher accuracy, which is consistent with the actual characteristics of the close multi-coalseam of the Xiaokang mine. This study provides some references to the subsidence monitoring and parameter inversion of close multi-coalseam mining.
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    Management Science
    Impact of Positive Followership Characteristics on Employees’ Innovation Behavior: The Role of Perceived Human Resources Management Strength and Job Embeddedness
    JIA Jian-feng, ZHAO Yang, LIU Qiu-yu
    2022, 43 (6):  905-912.  DOI: 10.12068/j.issn.1005-3026.2022.06.020
    Abstract ( 535 )   HTML ( 10)   PDF (508KB) ( 246 )  
    Based on social cognitive theory, the influence from positive followership characteristics on employees’ innovation behavior is focused upon, and the mediating effect of perceived human resources management strength and the moderating effect of job embeddedness are verified. Based on the 415 survey data, the conclusions are as follows. Firstly, positive followership characteristics have positive influence on perceived human resources management strength. Secondly, perceived human resources management strength has positive influence on employees’ innovation behavior. Thirdly, perceived human resources management strength partially mediates the relationship between positive followership characteristics and employees’ innovation behavior. Fourthly, job embeddedness plays a positive moderating role between perceived human resources management strength and employees’ innovation behavior. The result provides new ideas for enterprises to guide employee innovation.
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