bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on sentiment analysis of short text based on Attention
Authors: Li Haotian , Hui Cao , Xiaxia Zhang
Published: August 2020

In order to classify the short essays, a circulating neural network is used to classify the texts by natural language processing technology. Recurrent neural network has some advantages in processing text sequence with memory function. In this paper, BiLSTM algorithm is used to extract text data features, and self-attention mechanism is introduced to improve the fitting ability of the model. The accuracy of this model algorithm on text emotion classification task is 78.1%, which is improved compared with LSTM and CNN neural network model.
Topic Evolution Analysis of COVID-19 News Articles
Authors: Bai Yun , Jia Suling , Chen Lao
Published: August 2020

Recently, numerous media publishes various news on the latest developments every day due to the global spread of COVID-19. The news provides rich information about COVID-19 and includes a wide range of evolving topics. Our study is intended to develop a dynamic topic analysis system to monitor the evolution of the large-scale text data topics and assist with the social management and policymaking. The system expands the Dynamic Topic Model (DTM) with two modules: data sparsity computing and topic number selecting, which makes the experimental process more natural and generalizable. Data sparsity is designed to determine the length of single time slice. UCI, UMass and NPMI are introduced for choosing the optimal number of topics. This paper explores CBC news articles using DTM and captures the impact of COVID-19 on various aspects and the development of specific events. The experimental results demonstrate the effectiveness of our system for discovering and tracking the evolving topics. This system also plays an important role to improve the awareness of the public and serves as an analysis platform for government.
An Efficient Configuration Scheme of CGRA for Block Ciphers
Authors: Wei Jinghe , Wang Yufeng , Sun Jinjun , Yang Jinjiang
Published: August 2020

An Efficient Configuration Scheme based on Configuration Context (ECSCC) is proposed to decrease the size of configuration memory and the time of configuration transmission. The ECSCC is applied to a coarse-grained reconfigurable architecture (CGRA) which is implemented under TSMC 40nm CMOS technology to compare with similar work. The results show that the proposed ECSCC improves the area efficiency by 21.56 X and the energy efficiency by 3.97X.
Analysis of DNS Security Threats on campus network
Authors: Sha Feng , Wei Ying , Wenzhi Wu
Published: August 2020

DNS, as the entrance to Internet application access, is the only way for all business access. Normal services must access services through DNS, and malicious programs also need to be connected through DNS. In this paper, we focus on the analysis of campus network egress data using traffic analysis technology. And we pay attention to DNS-related data, hoping to find useful information about network attack. Since we collected data for about a month (mainly data about DNS data), we found many attacks and a large number of computer viruses. They are hidden in the normal data stream, but can be recognized by DNS data.
Analysis of identifying COVID-19 with deep learning model
Authors: Fan B B , Yang H
Published: August 2020

Coronary Virus Disease 2019 swept the world and caused serious impact on human society. Doctors usually use CT scan pictures and chest X-ray images to determine whether a patient is infected. Many researchers try to use deep learning methods to test COVID-19 of patients. However, there are many problems when using deep learning methods for feature extraction, such as: fewer data samples, unclear pictures, and pictures containing special marks. This article uses deep learning methods for COVID-19 detection and visual analysis of popular deep learning methods. Experiments verify that when using deep learning in the public small sample COVID-19 dataset, a small part of the test results are not reliable. We propose solutions to the problems of deep learning during COVID-19 detection.
SoS Architectural Requirements Modeling and Analysis
Authors: Dong Qingchao , Xu Junming , Qiao Yongjun , Ren Huifeng
Published: August 2020

Analysing the architectural requirements of System-of-Systems is a daunting task, usually involving a complicated process of enterprise architecture modeling and verifying. So the paper proposes a method of capability-oriented requirements modeling for developing the architecture requirements of System-of-Systems. A multi-layer ontologies framework is suggested to model the architecture requirements. To check the consistency of performance requirements, a formal inference method is designed to verify the requirements models. Finally, a case study is provided to demonstrate the applicability of the method.
Kernel correlation filters based on feature fusion for visual tracking
Authors: Yang Bo , Hu Xiaopeng , Wang Fan
Published: August 2020

This paper presents a CF-based method for robust visual tracking by multiple features fusion. HOG features and high-level CNN features are used to enhance tracking performance. First, different features are extracted from the target. Secondly, the extracted features are employed to learn the corresponding discriminant models, which are used to generate response maps respectively. Finally, an accurate response map can be obtained by fusing multiple response maps. In addition, we propose a model update strategy to reduce model drift under occlusion. The OTB benchmark is used to test the proposed method. Experimental results show that the proposed method can significantly improve tracking performance in complex situations especially in occlusion and fast motion. In addition, compared with several state-of-the-art methods, the proposed method shows competitive accuracy rate and success rate.
X—Ray Digital Image Advanced Processing and Buffer Layer Defect Intelligent Identification of Power Cable
Authors: Liu Sanwei , Zhang Liu , Duan Jianjia , Zhang Jun , Huang Fuyong , Duan X-Iaoli , Zeng Zeyu
Published: August 2020

With the rapid modernization of the city, power cable has been widely used in the process of urban construction. In the course of cable operation, cable faults become more and more frequent, which has a great impact on national economy and people’s life. The method of digital X-ray imaging can realize the nondestructive testing of power cable body and obtain clear and intuitive X-ray digital image. But it lacks the advanced processing and defect recognition method of X-ray digital image, and can not directly detect and identify the cable body and defect from the original digital image. Therefore, this paper studies the power cable X-ray digital image advanced processing and buffer layer defect intelligent identification technology. By using gray scale processing technology, the original image gray scale range is compressed to the human eye identifiable range, and then the defect identification is carried out. Then the traditional convolution neural network CNN and the full convolution neural network FCN are used to train the image data to realize the intelligent recognition of the power cable buffer layer defect. The research shows that compared with the traditional convolution neural network CNN, the full convolution neural network FCN proposed in this paper has more clear and intuitive recognition effect.
Simulation and Optimization of Flow Field in Jujube Hot Air Drying Room
Authors: Liu Rui , Dong Ji-Xian , Wang Dong , Wen Jia-Hao , Wang Yi
Published: August 2020

Numerical simulation of the flow field of chrysanthemum hot air drying chamber before and after optimization was carried out by using porous media model. To solve this problem, by setting the optimization scheme of the turbulence fan, the wind speed non-uniformity coefficient M in multiple sections was reduced from 125.51%, 149.27%, 144.81%, 135.63% and 106.45% to 90.44%, 116.15%, 86.92%, 77.49% and 76.67%, respectively. After flow field optimization, airflow velocity in the middle and rear of drying chamber increases significantly, and airflow uniformity in the whole space is improved.
Design and Optimization of Extraction Process of Sterile Seed Long Fiber
Authors: Sun Juyan , Liu Jiazhen , Tang Yu , Duan Shiming
Published: August 2020

We carried out research & analysis and development & design on the problems such as unreasonable structure of outdated process equipment and device, imperfect matching process and incomplete process link in the sterile cottonseed long fiber extraction, presented structural schemes for main machine and key fittings, and configured novel processing technology for sterile seed long fiber extraction, which achieves higher flexibility and adaptability of the processing technology and a machine-hour processing capacity of 400kg/h which is 2~3 times that of old model. And we proposed that the linear speed ratio of taker-in roller to roller shall not exceed 2,500, and obtained their reasonable speed at the optimum performance. The promoted application of this technology is of great significance to improve quality and efficiency of textile and cotton tailings treatment.
Analysis of key technologies to achieve autonomous driving on closed roads in the near future
Authors: Yang Guang , Chen Xiaoyue
Published: August 2020

In recent years, autonomous driving has received widespread attention worldwide. Many car companies and Internet companies have been competing for research and development. This article first reviews the current status of autonomous driving at home and abroad, then discusses key technologies for autonomous driving such as environmental perception, high-precision maps and navigation and positioning, path planning, and motion control. At the same time, the current situation, problems and solutions of autonomous driving on closed roads are discussed.
Instantaneous torque control is directly based on sliding mode control of SRM
Authors: Huang Xianghui , He Shuaishuai
Published: August 2020

Since the sliding mode control (SMC) of the sliding mode can be designed, and is independent of parameter variations and disturbances outside of the control target, the sliding mode control has the advantages of fast response, insensitive to the parameter change and external disturbance, and is easy to realize other control systems. It is an effective way to solve nonlinear problems. Characteristics inherent nonlinearity and strong coupling of the switched reluctance motor (SRM) itself, based on the traditional text directly on the instantaneous torque control, the torque distribution function provides a real-time compensation scheme. In Matlab/Simulink environment, the simulation results show that the improved control strategies can reduce torque ripple of SRM, increase the robustness of the system.
Review of Intelligent Development of Cigarette Maker’s Control System
Authors: Zhang Lihong , Yu Yonglong , Li Yuliang , Jin Wenliang
Published: August 2020

In recent years, the electronic control system of cigarette maker has been developed rapidly. The embedded IPC replaces the traditional “PLC+ high-speed processing board card” and is applied in the electronic control system of ultra-high speed winch unit, which solves the problem of poor stability of the original multi-platform. Under the new EtherCAT architecture, the intelligent development of the electronic control system of cigarette maker has become a new trend. In order to better improve the intelligent function of the electronic control system of cigarette maker, the intelligent development trend of the electronic control system of cigarette maker based on embedded IPC will be elaborated in detail.
Research on Intelligent Optimization of Bulk Cargo Terminal Control System
Authors: Wang Xuelin , Shi Hankun
Published: August 2020

Aiming at the problems of lagging automation and low informationization of bulk cargo terminals, this paper has optimized the control system of bulk cargo terminals, and improved the characteristics and functions of the control system. Based on the completion of the existing remote start and stop processes and equipment, the database, fault diagnosis and information management of the bulk cargo terminal control system are optimized, which improves the control efficiency and operability of the control system. The transformation and upgrading of the control system has played a good role in promoting the development and construction of smart ports.
Research on the design of intelligent cognitive training products for the elderly
Authors: Xue Yanmin , Zhang Yuanle
Published: August 2020

The purpose of this article is to design and study the smart cognitive training products for the elderly.This paper mainly studies how to prevent and improve the cognitive decline of the elderly in the market,analyzes the current situation and problems of the products in the market,studies the needs of users, finds out the functional needs, emotional needs and interactive experience needs of users, and further designs the intelligent cognitive training which is helpful to the cognitive training of the elderly according to the research result.
Design and application of double closed loop weight control system for cigarette maker
Authors: Li Yuliang , Zhou Xiaozhong , Zhang Lihong
Published: August 2020

In order to solve the problem that the precision of cigarette weight control system is not high enough in cigarette machine production, a double closed loop weight control system of cigarette machine is designed according to the characteristics of cigarette machine control system. This system takes IPC as the control core. Firstly, the current cigarette weight is obtained, then the weight deviation is calculated, and then the distance to be moved by the actuator is calculated based on the deviation. Then the current position of the actuator is obtained, and the target position of the actuator is calculated. The results show that the long-term deviation of the weight control system using the double closed-loop control method can be reduced to less than 4.0mg during the production of the target weight of 490mg cigarette, which is 0.8mg lower than that of the single closed-loop control method. This technology can improve the quality of cigarette process and reduce the overall consumption.
A Robust Beamforming Algorithm Based on Covariance Matrix Reconstruction and Steering Vector Estimation
Authors: Liang Jian , Jiang Defu , Han Yan , Zhang Yujie , Xie Zaipeng
Published: August 2020

Adaptive beamforming algorithms often suffer from performance degradation due to the presence of the desired signal component in the interference-plus-noise covariance matrix (IPNCM) and mismatch of steering vector. In order to improve the robustness of the beamforming algorithm performance, a new robust adaptive beamforming algorithm is proposed in this paper. In the proposed algorithm, Capon spatial spectrum is first used to reconstruct the IPNCM. Then, based on the robust Capon beamforming algorithm based on the steering vector uncertain set, new constraints are added so that the steering vector does not converge to the interference direction. The proposed beamforming algorithm is a non-convex quadratic constraint quadratic programming (QCQP) problem that is solved using semidefinite programming (SDP) relaxation. Simulation results show that the proposed algorithm is more robust than some other existing algorithms and is closest to the optimal solution.
Harm and control of hydraulic oil pollution in coal mine machinery
Authors: Zhang Huirong , Yao Zhongfu
Published: August 2020

Coal mining machinery such as shearer is one of the most important comprehensive mining equipment in coal mine. Once it breaks down, the consequences cannot be estimated. The data shows that about 2 / 3 of the faults in the hydraulic system of coal mine machinery are caused by the pollution of hydraulic oil. Therefore, this paper first analyzes the types and properties of various pollutants, then describes the harm of pollutants to the hydraulic system, and finally puts forward a comprehensive control scheme of hydraulic oil pollution, which provides a reference for engineering practice.
Development of real-time prediction module for precision and error of CNC system finishing
Authors: Lei Liang , Zhang Ning , Cai Peng
Published: August 2020

High speed and high precision are the important trends in the development of CNC machine tools. In order to improve the machining accuracy of CNC machine tools, the errors of CNC machine tools must be reduced as much as possible. Generally speaking, the errors of CNC machine tools include spatial errors, thermal errors, cutting force errors, tool wear errors, etc., in which spatial errors account for a large part of CNC machine tool errors, so reasonable control of reducing spatial errors is of great significance to improve the accuracy of CNC machine tools. Methods commonly used to reduce spatial errors include error prevention methods and error compensation methods. Error prevention is a method to eliminate and reduce error sources through design, manufacturing, assembly, etc. Although this method can reduce the original error, it is limited by improving manufacturing and assembly accuracy to reduce errors, and it is economically expensive. The error compensation method is to artificially create a new error to offset the current original error to achieve the purpose of improving machining accuracy. This method is easy to implement and has low cost. Therefore, the error compensation method is the most economical and effective method to improve the accuracy of the machine tool.
Design and implementation of temperature and humidity monitoring system for small cold storage of fruit and vegetable based on Arduino
Authors: Tang Xiuying , Tan Chao , Chen Aibin , Li Zhenghong , Shuai Renzheng
Published: August 2020

At present, the utilization rate of small cold storage for fruit and vegetable in Yunnan is low, and it is necessary to carry out regional management of cold storage in order to save energy and improve the utilization rate. Because different fruits and vegetables need different refrigeration temperatures, so real-time temperature and humidity monitoring is particularly important. For meeting this requirement, this paper designs an arduino-based temperature and humidity monitoring system for small cold storage of fruit and vegetable. The system mainly includes hardware and software parts. Handware component includes Arduino Mega2560, ESP8266, Zigbee, DHT11 temperature and humidity sensor, and OLED display and the software component includes the Arduino IDE, UartAssist serial debugging assistant, Lighting. Blinker. Finally, the whole system is tested, and the test results show that the system has the characteristics of remote viewing, high measuring accuracy and convenient use, and the system could meet the needs of temperature and humidity management for small cold storage.
Hybrid Position/Force Control with Virtual Impedance Model of Robot Manipulators
Authors: Hu Guanhua , Huang Qingjiu , Hanafusa Takuya
Published: August 2020

Industrial robots require force control in applications such as grinding, and impedance control is a representative method of force control. However, the current impedance control has no clear solution to the hybrid control of position and force for robot manipulators. Therefore, this paper distinguished the position control and force control of the top of robot according to the axis, converted the desired force to position compensation based on the kinematics and dynamics of the robot, and proposed a hybrid position/force control with virtual impedance model of robot manipulators. Moreover, this paper established a grinding simulation model of a three-joint robot manipulator on Matlab/Simulink, and verified the effectiveness of the control method proposed in this paper by a numerical analysis of grinding simulation.
Road elevation map estimation based on affine transformation and stereo matching
Authors: Feng Y H , Zhang R H , Zhai S
Published: August 2020

This paper presents a road elevation map estimation method based on affine transformation. A geometric model of reference plane and stereo rig is proposed. The model showed that the height of 3-D points relative to the reference plane can be described by the proposed disparity relative to the reference plane. The reference plane is implicitly established by performing an affine transformation on target image. A local based stereo matching is applied to estimate subpixel disparity map. The elevation map can be easily estimated from subpixel disparity map using proposed elevation computation model. The experimental results on real-word road scenes show that the proposed method can provide accurate road elevation estimation.
Low-cost Detection of Surface Defects on Ultra-smooth Optical Substrates
Authors: Chen Shiyi , Nie Xiaoming , Tan Zhongqi , Zhang Bin
Published: August 2020

In order to better measure the surface processing quality of ultra-smooth optical substrates, an image acquisition system of laser scattering microscope is built based on the principle of microscopic dark-field scattering imaging, which can help acquire a substrate sample scattering image within 10 seconds. Various kinds of defects on the surface of the optical substrates can be observed, and in this way, the simple and qualitative analysis of the surface quality of the substrates is realized.
Simulation Research on Decoupling Control of Active-disturbance-rejection of Omnidirectional Robot
Authors: Shen T , Xie X Y , Li J Y , Dong X B , Gao X H
Published: August 2020

Active-disturbance-rejection controlling method is proposed in this essay aiming at the problems of omnidirectional robots, such as complex model, strong coupling and controlling difficulty caused by internal and external stochastic disturbance. Taking eight-wheel omnidirectional robots as the example, the coupling method based on active-disturbance-rejection is designed by analysing the kinematic-dynamic model of the robot. Non-linear function is used as the state feedback of the components of the active-disturbance rejection controller, and extended state observe is adopted to estimate the internal and external stochastic disturbances and to provide active disturbance compensation. Through simulation experiment comparing with traditional PID controller, the decoupled active-disturbance-rejection controller can control omnidirectional robots better inhibit the unknown disturbance and improve the performance of the system.
Reform of mechanical manufacturing experiment teaching based on Excellence in Engineer Program
Authors: Liang Yanmei , Zhao Rui , Bao Jiading
Published: August 2020

This paper will expound the new demand of talent training based on Excellent engineer education and the significance of experimental teaching, as well as analyze the current situation of experimental teaching. Then, the reform countermeasures of mechanical manufacturing experimental teaching based on “Excellent Engineer Education” have been put forward, so as to provide reliable reference for relevant teachers.
Design of dual band common aperture continuous zoom optical system
Authors: Jia Bing , Zhao Yuchen , Yuan Xie
Published: August 2020

To rapidly accommodate social demands and the requirements of imaging system under increasingly complex application environment, and to optimize the complex and bulky existing multi-spectrum continuous zoom optical systems, a short-wave(0.9μm to 1.7μm) and long-wave(7.7μm to 9.3μm) infrared radiation common aperture continuous zoom optical system was designed, the focal lengths of short-wave and long-wave infrared radiation were 8mm to 32mm and 30mm to 120mm respectively, the zoom ratio was 4.The system was analysed according to the theory of positive group compensated zoom, powers of the zoom group and the compensation group were well matched, only ZNSE and ZNS materials were applied in the common group. The results of the experiment show that the optical system is compact in structure, and has good image quality in different spectrums, can work around the clock under complex environment.
Research on Erection System of a Vehicle Missile
Authors: Yang Minbo , Ji Yueyue , Ma Cong , Wu Qipeng
Published: August 2020

The defects of existing erection system of a vehicle missile mainly include long erection time, large volume and poor adaptability to harsh environmental condition, so a new type of gas-fired electric erection system is designed. After the structure and working principle are introduced, the similar model of a missile is established according to the similarity theory. Through the analysis of the working process of the system, the mathematical model is established and the simulation model is also established by using Matlab / Simulink. Finally, the simulation analysis is carried out. The result shows that the erection system can achieve the quick erection of a heavy vehicle missile, which lays the foundation for the subsequent engineering application.
Construction of hydraulic chuck reliability test platform by ARM DSP dual-core system
Authors: Liu Haitao , Du Hubing , Wang Jianhua
Published: August 2020

To improve the data acquisition speed and accuracy of hydraulic chuck reliability test, a dual-core data acquisition system with ARM and DSP is constructed in combination with their respective characteristics. Taking full advantage of DSP’s fast operation speed, arm is suitable for interface, control and display, so as to realize high-speed and high-precision data acquisition and real-time online data processing, as well as various real-time data acquisition and information exchange functions.
Research on Transmission Performance of A Seven-gear Three-degree-of-freedom Planetary Gear Automatic Transmission Based on Graph Theory and Matrix Equation
Authors: Fan Yi
Published: August 2020

The transmission performance analysis of planetary gear automatic transmission is helpful for the following structural size optimization, hydraulic design and electric control design. The current graphic method has the disadvantages of low calculation accuracy and lack of intuition in numerical analysis method. This paper proposes a method to analyze the transmission performance based on graph theory and matrix equation. Firstly, a graph theory analysis model is established for the self-designed seven-gear three-degree-of-freedom planetary gear automatic transmission, and the structural characteristics of the transmission are analyzed. Then, on the basis of analyzing the shift actuator worksheet, the motion analysis model and torque analysis model of typical gears are designed by taking the first gear and the reverse gear as examples, and the speed and torque values of all gears of the transmission are calculated by using the corresponding matrix equation. Finally, the power flow diagram of the typical gear is established by taking the first gear and the fourth gear as examples, and the direction and numerical value of power flow are identified on the diagram. The results show that the method can realize the combination of qualitative and quantitative analysis for the transmission performance analysis of the planetary gear automatic transmission with multiple gears and multiple degrees of freedom, which is more intuitive, accurate and efficient.
Motion Simulation of Bionic Hexapod Robot Based on ADAMS/MATLAB Co-simulation
Authors: Liu Tao , Zhang Zhipeng , Liu Yiqun , Fan Xuanxia
Published: August 2020

This paper mainly studies the kinematic simulation of hexapod robot when going straight, turning and climbing stairs based on MATLAB and ADAMS. First, the kinematic model of the robot was established based on the D-H method. On this basis, the compound cycloid and half-wave sine function were used to plan the foot trajectory of the robot during straight and turning. Through ADAMS/ MATLAB co-simulation, the hexapod robot has completed the tasks of straight, turning and climbing the stepped terrain. The simulation results show that the planned gait can be more flexible to complete the turning and climbing the stepped ground, and the related results can help the small hexapod robot to quickly verify the gait algorithm and reduce the design development cycle.
Design & Simulation of a Superimposed Hydraulic Back Pressure Valve with Adaptive Back Pressure
Authors: Mao Xuyao , Ding Hongyuan , Li Bin , Wu Chao , Wang Nei
Published: August 2020

A superimposed hydraulic back pressure valve with adaptive back pressure was designed. The back pressure of the valve changes as the diving depth of underwater vehicles changes, and is always higher than outboard environmental pressure by an adjustable value, preferred 0.5MPa, to avoid leakage of environmental medium to the inboard hydraulic system. The valve was designed in a pilot-operated style with a flat valve port of main valve. Variable damping plugs were used to easily regulate the dynamic performance of the valve. And an isolation device was adopted to isolate the contact between the inboard and outboard media. The static mathematic models of the valve were established and simulations were carried out. The simulation results show the valve has good pressure stability and flow adaptability, and its back pressure changes with the change of outboard pressure well.
Research on Modeling of Satellite On-orbit Operation Procedure
Authors: Lv Wei , He Xiaoyu , Qin Wei
Published: August 2020

Aiming at the demand of the TT&C system for the on-orbit satellite to automatically perform various operations, the paper proposes a modeling technology for on-orbit operation procedures. Based on the formal method, a grammer specification of operating rules is formulated, and modeling rules of operating rules are defined by XML Schema. The process of graphical editing, serialization and deserialization of operating rules is presented. Practical application shows that it can improve the design and execution efficiency of operating procedures.
System and Design of a AGV for Flexible Production Line
Authors: Xu Shuyang , Cao Shukun , Gao Kuizeng , Cao Wenlong
Published: August 2020

Automated guided vehicles (AGV) are future products that can provide driverless transportation and can transport a variety of products without manual intervention in production, logistics, warehouse and distribution environments. The main advantage of AGV is that they can operate as independent systems with higher efficiency. The proposed work has the main function of AGV, of which EPROM is used to save data. Taking advantage of EPROM, the robot can maintain and continue to execute the current program even if the system returns to the power-on state after a period of power failure in a crisis situation. Compared with manual functions, AGV provides higher efficiency for many industries. The ultrasonic sensor assists the controller, which can realize the obstacle detection function in the robot. Through the artificial intelligence controlled by Bluetooth/Wi-Fi, AGV can be further improved to the level of automation.
Hexapod robot fault tolerant gait on slope and simulation verification
Authors: Liu Tao , Fan Xuanxia , Liu Yiqun , Jia Xiaowei , Deng Yuguo
Published: August 2020

Currently, hexapod robot has been widely used in the field of outdoor detection and nuclear power disaster relief because of its adaptability to terrain, excellent movement performance and redundant fault tolerance. In this paper, fault-tolerant gait and motion planning method on the slope are researched. Firstly, the kinematics model of the robot on the slope is established, and the Jacobian matrix mapping the foot end velocity and joint velocity is derived, which is the basis of the robot movement. Then the phase sequence of the robot with one leg fault is planned to solve the problem of leg phase coordination. After then, the adjustment strategy of the centre of gravity on the slope is planned, which can effectively improve the stability of the robot. Finally, a simulation is demonstrated to verify the research.
Study on the influence of the vehicle rear plan on wake flow field
Authors: Wu L L , Fu Y , Bu X B , Zhang X L , Ma X L
Published: August 2020

The rear plan is one of the key factors that affect the separation of air flow at the vehicle rear.It has important theoretical guidance and engineering significance to study the influence of the rear plan on wake flow field for the early development and design of vehicle shape.Based on a simplified SUV model, the drag coefficients of the models with different rear plans are calculated. The velocity separation, pressure distribution and energy dissipation of air flow at the vehicle rear are compared and analyzed,demonstrating that the rear plan has influence on air separation and the formation of wake vortex at the vehicle rear.It is found that with the decrease of the rear plan, the separation of the air flow at the vehicle rear becomes weaker, the wake vortex gets smaller, and the drag coefficient reduces.
Innovative design of side mould structure based on TRIZ theory
Authors: Chen Jiwen , Yu Yongpeng , Ji Shuai , Yang Peiwu
Published: August 2020

In order to meet the requirements of domestic prefabricated buildings and PC production lines, taking the side mould structure as the research object, an innovative design of the side mould structure based on TRIZ theory is proposed. The tools of TRIZ’s nine-screen method and conflict matrix are used to complete the innovation of the plugging device for the side mould reinforcement hole,and by using steel wire connection, the aluminum alloy sealing device can complete synchronous action and solve the problem of reinforcement hole leakage. Through the object field analysis tool in the TRIZ theory, to establish the function related to the existing system or new technology system problems, the double rocker mechanism is used to make the reset action and the demolding action of the side mould sealing device complete in a linked manner, to realize the design of the demoulding device and the side mould fixing device. The calculation and verification of the side mould structure verify that the side mould stiffness meets the production requirements, and improves the accuracy and placement accuracy of the side mould.
Research on obstacle detection and path planning based on visual navigation for mobile robot
Authors: Zheng Yixiao , Yan Bixi , Ma Chao , Wang Xinyu , Xue Haoyang
Published: August 2020

Both obstacle and path planning are of significance for autonomous visual navigation of a mobile robot which is able to realize free movement and obstacle avoidance. In this paper, a scheme of obstacle detection which is based on binocular vision to identify obstacles is constructed and it is combined with improved A* algorithm for obstacle avoidance motion for mobile robot platform. First, a binocular vision system to detect the robot’s perception of the environment is used and the visual information is obtained. Then a Gaussian filter is used to reduce the noise in the image, and the grayscale image is obtained through the binocular vision system. The gray scale map is matched with SAD (Sum of Absolute Differences) in order to obtain the disparity image with comparison. Second, the location information of the obstacle is extracted through the environmental depth information contained in the disparity image, and the improved A* algorithm is used as the path planning algorithm in this paper, which can modify the path of the planning error. Furthermore, the detection experiment of the robot visual obstacle avoidance system was established and the optimal path was obtained. The examples show that, the obstacle avoidance system can complete the task of obstacle detection and give a better path for the mobile robot.
Design of the Unsteady Vibrating Signals Order Analysis System for the Rotating Machinery
Authors: Liu Qihe
Published: August 2020

To eliminate the spectral ambiguity generated by FFT analysis method, the computational order tracking (COT) method is adopted to process the unsteady vibrating signals acquired from the rotating machinery. In this paper, the Lagrange 7-point interpolation algorithm is proposed to calculate the speed profile, the subsection interpolation method is developed based on the given angular acceleration threshold to obtain resampling time, and the sliding low-pass filtering interpolation method is adopted for angular resampling. According to these algorithms, the order analysis system is developed based on LabVIEW, and it is verified by the tests of simulation signals.
Analysis and Optimization of a Radial Flux Variable Reluctance Resolver
Authors: Pan Haihong , Wang Le , Yin Dejun
Published: August 2020

Variable Reluctance resolver as a shaft position detection unit has been wildly used in harsh environments because of high reliability. This paper uses the finite element method to analyze the influence of the harmonic components in the magnetic field on the accuracy of the resolver, and proposes a method to add slots at stator combined with optimizing the output winding distributions to reduce the harmonic content in the output voltage. Finally, the sinusoidal of output voltage turned out to be improved and the resolver met the measurement accuracy of ±30’.
Position Based Impedance Control of Electro-Hydrostatic Actuator
Authors: Zhou Guozhe , Lv Xin , Feng Tieshan , Gan Luoning
Published: August 2020

This paper presents a method for implementing position based impedance control (PBIC) in an electro-hydraulic actuator (EHA). Impedance control provides the actuator with compliance and facilitates the interaction with environment. Whereas most impedance control applications utilize electrical or valve-controlled hydraulic actuators, this work enables impedance control in a compact and efficient EHA. The selection of target impedance parameters is analysed and illustrated via root locus technique. The effectiveness of PBIC used in EHA and compliance of cylinder is shown in the impact test with several experimental results.
Tibetan-Chinese Neural Machine Translation Combining Attention Mechanism
Authors: Jiang Tao , Sun Hao , Dai Yu Gang , Liu Ding
Published: August 2020

Neural Machine Translation (NMT) has developed rapidly in recent years, and translation effects in most languages have surpassed statistical machine translation methods. The Seq2Seq framework has brought great advantages to machine translation, but the model still has great limitations in the ability to capture long-distance information. Recurrent neural networks (RNN) and LSTM networks are proposed to improve this problem, but the effect is not obvious. However, the proposal and application of the attention mechanism effectively compensated for this defect. This paper uses the attention mechanism as the basis to construct the encoder-decoder framework. This method analyzes the mechanism and principle of the attention model to implement the Tibetan-Chinese neural machine translation system. Compared with the previous neural network translation models, the results show that the translation model that incorporates the attention mechanism can obtain better translation results.
The principle and practice of measuring the sensitivity of power line spike pulse interference
Authors: Gao Tongguo , TaoWang  , Tang Daokui , Yang Jiaping
Published: August 2020

The measurement of power line spike interference sensitivity is an important item of EMC test. In this paper, the focus of the item and the principle of measurement are described. Combined with the engineering practice of cs06 project, a new way to solve the peak pulse interference of power line is given.
Research on the Determination Method of Acceleration Coefficient in Accelerated Reliability Test of Electronic Equipment
Authors: Yang Man , Yi Ming , Luo Gengxing , Huang Yuanmin
Published: August 2020

This paper analyzes the relationship between environmental stress and electronic equipment failure, studies the determination method of stress type, combination mode and stress value in reliability accelerated test of electronic equipment. Under given reliability accelerated test section, the acceleration coefficient calculation method of the reliability of electronic equipment are given, it can realize rapid assessment of highly reliable electronic equipment reliability, significantly reduce test time and test cycles, overcome traditional electronic equipment reliability test time is long, high cost, difficult to quickly evaluate the level of reliability of faults.
Multi-Model Stacking Ensemble Learning for Dropout Prediction in MOOCs
Authors: Zhou Ya , Xu Zhixiang
Published: August 2020

In recent years, with the rapid development of streaming media technology, massive open online courses (MOOC) have attracted unprecedented attention. Compared with the traditional offline teaching mode, the MOOC of online teaching has a higher degree of openness. Users can arbitrarily interrupt the study of a course according to their own interests, and have a higher dropout rate. The existing single machine learning model needs to be improved in terms of prediction accuracy. In this paper, a dropout prediction model based on multi-model stacking ensemble learning (MMSE) is proposed to further improve the accuracy of MOOC dropout prediction. The model mainly includes two parts: data preprocessing and model building. In the data preprocessing part, the student’s log records are used to design data features in weeks. In the model building part, a two-layer ensemble learning model is established. In the first layer, 5-fold cross-validation is used to train five different base classifiers. The second layer uses the XGBoost algorithm to combine the prediction results of the first layer to predict MOOC dropout. The experimental results on the KDDcup2015 real data set show that the MMSE model has achieved better results than the single model.
Research on the Characteristics of Wireless Power Transfer in Non-ferromagnetic Metal Pipe
Authors: Li Changsheng , Liu Yong , Hu Defu , Sun Wei
Published: August 2020

With the development of various electronics, the way of transmitting energy by wire has brought increasingly negative effects on the operability and convenience of products. As wireless power transfer (WPT) technology requires no transmission lines, it has received increasingly wide attention. Most of the previous research on the technology of magnetic resonant coupling WPT mainly focused on the transmission of energy in the air. This paper establishes the wireless power transfer system model under non-ferromagnetic metallic environment and studies the effect of non-ferromagnetic metallic environment on coil self-inductance L, mutual inductance M and coil resistance R of WPT system. On this basis, the study on the relationship between coil diameter and mutual inductance is carried out for aluminium pipe, and the relationship between coil diameter and diameter of metal pipe at the maximum mutual inductance is fitted. Besides, experimental verification is conducted for the change of mutual inductance between the coils of WPT system in the aluminium pipe, presenting that the actual measurement results of mutual inductance in the aluminium pipe are consistent with the theory.
Research on the Accuracy Control Technology of Automated Peritoneal Dialysis
Authors: Ge Shiqiang
Published: August 2020

The automated peritoneal dialysis is accepted increasingly. The automated peritoneal dialysis makes use of a device called automated peritoneal dialysis cycler to realize the automated treatment. The liquid quantity of dialysis treatment is an important index of peritoneal dialysis. Thus the flow calculation accuracy of the automated peritoneal dialysis cycler is one of the most important performances. However, due to the complex usage situations, the cyclers based on different principles are extremely affected by touching, flow resistance fluctuating, etc., which causes inaccuracy and instability. This paper investigated an accurate calculation model and a control algorithm to address these issues. Based on the State Equation of Ideal Gas, a calculation model is established. By analyzing the influence factors of time-varying flow resistance, a control algorithm is designed. A prototype with our method is developed and tested by experiments. The results show that the flow calculation errors are reduced significantly and the accuracy and stability are improved obviously. It proves that our method can realize an accurate flow calculating and effectively reduce errors and keep accuracy stable.
A Ka-band Balanced Feed Antenna with High Selectivity
Authors: Sun Yuanchen
Published: August 2020

In order to obtain a high-selectivity antenna array, a filter antenna based on balanced feed system is investigated in the paper. The balanced feed structure excites the each sub-array with the same phase and amplitude so that the radiation beam is stable steering to normal direction over the entire working bandwidth. Meanwhile, in order to reduce the overall size of the system and improve the selectivity of the antenna array, the filter will be integrated into the input port of the antenna array. The simulated bandwidth of VSWR less than 1.5 is 28.2 GHz∼31.2GHz, and the maximum gain of the antenna is 16.43 dB.
Analysis of Factors Affecting the Accuracy Evaluation of Range Estimation of Pure Electric Vehicles Based on CLTC-P
Authors: Wang Feifei , Dai Tianlu , Zheng Xiaobing , Pan Xiaolong , Lei Ligang
Published: August 2020

The estimation accuracy of the cruising range of electric vehicles is an important performance index of electric vehicles. Improving the accuracy of cruising range estimation is of great significance for improving the user acceptance of electric vehicles. This paper carried out vehicle tests under normal temperature environment based on China light-duty vehicle test cycle for passenger car (CLTC-P) under different battery state of charge and long-distance constant-speed driving, and use the determination coefficient to analyze and evaluate the accuracy of the metered range mileage. At the same time the paper deeply study the impact of different data collection frequencies and the vehicle’s metered range self-learning mode on the accuracy of the range mileage. This study provides theoretical support for the use of certain coefficients to study the accuracy of the estimated range of pure electric vehicles under unified scenarios and specific working conditions, and to establish a test and evaluation method for the accuracy of range of electric vehicles
Research on Development and Application of Mechanical Engineering Based on CNC Machining Technology
Authors: Zeng Hao
Published: August 2020

The machinery industry is an important foundation for the development of a country. It is very important and necessary to do a good job in the development of the machinery industry. In the new era, with the development and application of information technology and automation technology, it has provided a powerful boost for the development of modern machinery industry. By applying information technology and automatic control technology to the machinery industry, the technology to improve the information and automation level of the machinery industry is called CNC technology. Based on the analysis of the characteristics of CNC technology, the article analyzes and introduces the important influence it brings to the machining technology, and prospects the future development and intelligent trend of CNC technology.