bluuebunny/crossref_metadata_2025 huggingface dataset:
Interference classification and identification of TDCS based on improved convolutional neural network
Authors: Li Ming , Ren Qinghua , Wu Jialong
Published: November 2020

A classification and recognition algorithm based on short-time Fourier transform and convolutional neural network (STFT-CNN) is proposed to solve the common interference signal classification and recognition problem in transform domain communication systems. In this algorithm, the time-spectrum diagram of interference signals obtained by short-time Fourier transform is input into the vggnet-16 network model improved according to STFT characteristics for feature learning and training, and the classification and recognition of signals are completed. Simulation results show that the proposed algorithm for comprehensive recognition rate reached 97.7%, 6 kinds of jamming signal in low SNR circumstance still can reach more than 93% recognition rate, compared with the traditional algorithm, this method not only improves the classification recognition rate of single interference, but also improves the recognition of mixed interference ability, has the ability to resist low signal-to-noise ratio, makes the transform domain communication system can choose transform domain for anti-interference, provides theoretical basis and support for the application of convolutional neural network in anti-interference of communication system in transform domain.
A Review on Neural Style Transfer
Authors: Li Jiayue , Wang Qing , Chen Hong , An Jiahui , Li Shiji
Published: November 2020

Image style transfer is a method that can output styled images, which can both retain the original image content and add new artistic style. When using neural network, this method is referred as Neural Style Transfer (NST), which is a hot topic in the field of image processing and video processing. This article will provide a comprehensive overview of the current NST methods. Firstly, we introduce the current progress of NST from two aspects: the image-optimisation-based method and model-optimisation-based method. Then we compare and summarize different types of the NST algorithms. The review concludes with a discussion of applications of NST and some proposals for future research.
Ultrasound Image Segmentation of Thyroid Nodules Based On Joint Up-sampling
Authors: Wu Junxia , Zhang Zhenqing , Zhao Juanjuan , Qiang Yan
Published: November 2020

In view of the problem of inaccurate segmentation of thyroid nodule ultrasound images, a method of thyroid nodule ultrasound image segmentation based on joint up-sampling is proposed. In order to solve the problem of serious speckle noise in the original ultrasound data, preprocessing is performed to enhance the contrast between the nodule area and the background area. In order to achieve accurate positioning of the nodule target area, a joint up-sampling module is designed to fuse the context information of ordinary standard convolution and expansion convolution with different expansion coefficients. Experimental results show that the proposed method achieves 93.19% accuracy and dice similarity coefficient is 0.8558, which is better than other existing thyroid nodule segmentation network models.
Improving Convolutional Neural Network Expression via Difference Exponentially Linear Units
Authors: Hu Zhiying , Huang Hongbo , Ran Qinglin , Yuan Mingyang
Published: November 2020

Convolutional Neural Network (CNN) has been applied to various tasks with great success. Adding an activation function is an important way to introduce nonlinearity into convolutional neural networks. The commonly used activation functions mostly use different forms of negative feedback for the negative input, however, some researchers have recently proposed positive feedback methods for the negative input such as Concatenated Rectified Linear Units (CReLU) and Linearly Scaled Hyperbolic Tangent (LiSHT) and achieved better performance. To explore this idea further more, we propose a new activation function called Difference Exponentially Linear Unit (DELU). The proposed DELU activation function can optionally provide positive and negative feedback for different values of negative inputs. Our experimental results on the commonly used datasets such as Fashion Mnist, CIFAR10, and Imagenet show that DELU outperforms other six activation functions, Leaky ReLU, ReLU, ELU, SELU, Swish, SERLU.
Research on HRRP target recognition based on one-dimensional stack convolutional autoencoder
Authors: Zhang Guoling , Wang Xiaodan , Li Rui , Lai Jie , Xiang Qian
Published: November 2020

Extracting key features from the radar high resolution range profile (HRRP) determines the accuracy and reliability of radar target recognition. Aiming at the problem of feature extraction and recognition in HRRP target recognition, a one-dimensional stack convolutional autoencoder (1D-sCAE) recognition method is proposed. Firstly, one-dimensional convolutional autoencoder is constructed to extract the deep features of one-dimensional HRRP signals by unsupervised learning. Then, multiple one-dimensional convolutional autoencoders are stacked to construct 1D-sCAE, and HRRP is classified by fine-tuning the network with label data. At the same time, for the overfitting problem of 1D-sCAE, dropout technology is added to optimize and improve the generalization performance. Through the simulated HRRP data of the target in the middle part of the trajectory, the experiment shows that the proposed algorithm has better feature extraction capabilities, higher recognition accuracy and stronger robustness than the typical deep neural networks.
Accurate Monocular Depth Estimation via Interaction of Hierarchical Features
Authors: Zhang Jiahao , Chen Dan , Lin Ye , Wu You
Published: November 2020

Monocular depth estimation is a challenging task, which assists in understanding 3D scene geometry from the same 2D scene. The ordinal-regression-method demonstrates superior performance in this issue but naive ordinal inference strategy for inferring the final depth values and naive operations to up-sample to the desired space scale introduce significant discretization errors and object boundary confusion. Firstly, we come up with a novel inference strategy to reduce the discretization errors. And then a specifically designed decoder that completes the fusion of different hierarchical features under guidance and the fusion feature reconstruction. We evaluate on a public monocular depth-estimation benchmark dataset (NYU Depth V2). The experimental results show that the method proposed outperforms other ordinal regression methods.
Method for extracting crack area on structure surface based on digital image processing technology
Authors: Jiang Song , Zhang Hua
Published: November 2020

According to the characteristics of the surface crack of the wall structure, the method of extracting and marking the surface crack area of the wall mechanism is studied by using the digital image processing technology. In this paper, the wall structure crack is taken as the research object, firstly, the nonlinear Bilateral Filters algorithm is used to suppress the noise and smooth the image; then the crack edge is extracted by Canny operator, all the crack edges are closed by mathematical morphology opening operation, and some non-crack contours are eliminated; finally, the non-crack area is deleted to realize the real mark of crack connected region. The analysis of the experimental results shows that the method proposed in this paper can realize the safe line monitoring of the cracks in the wall structure and mark the area where the real cracks are located.
Image Classification of Chicken Embryo Based on Matched Filter and Skeleton Curvature Feature
Authors: Jin Xue-Song , Li Jing , Du Xin
Published: November 2020

To solve the problem of nondestructive detection of egg formation activity in vaccine preparation, a new method based on matching filter for chicken embryo image blood vessels segmentation algorithm combined with the curvature feature of the blood vessels skeleton was proposed. Gaussian matching filter was used to enhance the contrast between the blood vessels and the background of the green channel image and the blood vessels were segmented from the background. Morphological methods was used to process the binary images to extract the vascular skeleton feature. The curvature of the vascular skeleton was calculated by using the least square method. Finally, the activity of chicken embryo was judged by combining the shape feature of blood vessel with the texture feature of chicken embryo extracted by gray level co-occurrence matrix algorithm. The experimental results show that this method has high accuracy in the classification experiment of chicken embryo images affected by spot noise, and meets the quality requirements of producing virus species in vaccine preparation.
Slave Coordinated Speed Analysis and Coordinated Control Method
Authors: Yan Hang , Sun Xuan , Ai Changsheng , Ren Gangchang , Zhang Baixing
Published: November 2020

When the container is being repaired, it is necessary to transfer the container to be repaired between the temporary storage area and the repair area. Due to the large size, when manually transported by forklift, the line of sight is blocked, there is a great safety hazard and efficiency. It is relatively low, and it is inconvenient to use a single mobile robot to carry it. Therefore, to solve this problem, a dual-mobile robot collaborative operation system is developed, and two mobile robots are used to move containers together to complete container maintenance and handling. Through the analysis of the cooperative handling of the dual mobile robots, a mathematical model of the cooperative movement of the dual mobile robots is established, and kinematics analysis is carried out to provide a theoretical basis for controlling the cooperative operation of the dual mobile robots.
A surface defect detection system for railway track based on machine vision
Authors: Zhao Kang , Luo Laizhen , Ren Zhengmin , Fu Qingchen
Published: November 2020

In order to detect rail surface defects more quickly and effectively, a rail surface defect detection system based on machine vision was constructed. A perfect lighting system is built to obtain high quality image information. At the same time, the linear CCD camera is used to collect the rail information, which is uploaded by FPGA, and the image information is processed and analyzed by MATLAB software in the upper computer. Through the methods of image denoising and image enhancement, the image quality is improved, and the image information suitable for operation is obtained; then, the rail positioning is completed by threshold segmentation, gray compensation and image binarization to simplify the image operation; finally, the final positioning of defects is realized through edge detection and feature extraction. By building a test platform on the rail maintenance vehicle, the rail surface defect information collected by the rail maintenance vehicle is analyzed and processed.
A novel scissor-type anti-shock seat employing rotary magnetorheological damper
Authors: Wang Tao , Dong Xiaomin , Yu Jianqiang , Li Xin , Yan Maosen
Published: November 2020

In order to improve the cushioning performance of anti-shock seat in an impact environment and protect the lives of occupant to the greatest extent, the cushioning performance of a new type of anti-shock seat combining a rotary magnetorheological (MR) damper and a scissor seat was studied. Aiming at the “bottoming out” characteristic of scissor seats after the cushioning stroke is exhausted, and the dynamic model of scissor seats with MR damper is established. In order to test the cushioning performance of the new anti-shock seat in an impact environment, a prototype MR damper was processed and assembled, and the cushioning performance of the seat under different impact speeds was tested using a drop impact test platform. The test results show that the new anti-shock seat can adjust the cushion stroke and cushion force value to keep the acceleration limit of the occupant within the tolerance range, thereby effectively reducing the risk of injury.
A hardware-in-the-loop simulation platform for distributed UAV swarms
Authors: Wang Zhenbei , Li Jie , Yang Chengwei , Yang Yu
Published: November 2020

To improve the functional verification efficiency of intelligent UAV swarm systems, this paper proposes a distributed UAV swarm hardware-in-loop (HIL) simulation platform. The proposed platform uses fine-grained 3D scenes and real aircraft aerodynamic models as inputs to simulate the control and mission decision-making process of the UAV swarm by building a swarm data interaction network. The simulation platform is equipped with real on-board electrical equipments, which can fully verify the compatibility between software and hardware in the UAV swarm system and is able to shorten the research cycle effectively. The platform supports the addition and deletion of all-digital virtual simulation nodes and can be used for large-scale swarms. The tests on individual strap-down terminal guidance and multi-aircraft coordinated search show that the platform has good simulation results for features such as data interaction, autonomous decision-making, and control of UAV swarms.
Research on Aerial Robot Based on Visual Servo
Authors: Deng Tianchen
Published: November 2020

Towards target grasping by an aerial manipulator, an aerial manipulator system is presented, for which a separated control strategy is adopted. In this paper, a suitable adaptive visual servo controller is proposed based on the original aerial manipulator system, and a visual servo controller is designed based on the depth independent image Jacobian matrix. Thus, the grasping motion of the manipulator is controlled by the visual servo of the monocular camera, which can greatly enhance the functionality and speed of the aerial manipulator system. Furthermore, a unique single degree of freedom joint collocation camera is designed to enable the camera to lock the target object at any time during the motion of aircraft. Finally, this paper designs a unique state machine system, which can make the control system switch into any state.
Design of AGV human-machine interactive control system
Authors: Wang Zhe , Ai Chang Sheng , Wang Zhiyong , Zheng Lei
Published: November 2020

The outdoor intelligent transportation of a pharmaceutical factory requires the workshop to put forward task requirements according to the situation and provide multiple AGVs that can meet both man-machine control and networked scheduling. On the basis of existing AGV, an AGV control method based on human-computer interaction is proposed. First, design the overall architecture of the control system, use the touch screen to design and develop the AGV mobile client and task request client to form an industrial wireless network. The establishment of a network enables the AGV mobile client, task request client and vehicle management system to achieve cross-platform communication. Based on this, the client system sets and controls the AGV, which effectively solves the AGV’s man-machine control and networking scheduling problems. After functional testing and performance verification, the system works stably, with good flexibility and scalability.
Investigation of an Automobile magnetorheological damper with asymmetric mechanical characteristics
Authors: Song Xianyu , Dong Xiaomin , Yan Maosen , Li Xin
Published: November 2020

In order to reduce the cost of sensors in automotive magnetorheological suspension systems and improve system reliability, a structural design scheme of automotive magnetorheological dampers with asymmetric mechanical characteristics is proposed. In this structure, the rebound damping coefficient with or without the action of the magnetic field will be greater than the compression damping coefficient, which solves the influence of the traditional magnetorheological damper limited by its own adjustable range, and continuously outputs the passive damper under different working conditions. According to the structural design plan, the mechanical output characteristics of the system are analysed theoretically, and the prototype machine is processed and tested. The research results show that the designed magnetorheological damper has the working characteristics of continuously outputting asymmetric damping force, which verifies the effectiveness of the design ideas and methods.
Research And Analysis Of Three Degree Of Freedom Drivetrain Model For Wind Turbine
Authors: Du Jing , Wang Yan
Published: November 2020

According to the characteristics of the drivetrain shaft system of large-scale wind turbines, a three-degree-of-freedom wind turbine drivetrain dynamic model is established using Lagrangian equations and dynamic equations, and the drivetrain torsion mathematical model and multi-mass simplified model are extended to Three-degree-of-freedom multi-body dynamics mathematical model. Using this mathematical model can effectively carry out theoretical analysis on the vibration model of wind power generators, and provide a theoretical reference for the design and simulation of the drivetrain. Taking this three-degree-of-freedom mathematical model as a prototype, a three-degree-of-freedom(3-DOF) rigid-flexible coupling multi-body dynamics simulation model is established in Simpack. Perform frequency domain analysis in the dynamic equilibrium state of the drivetrain model to obtain frequency characteristics such as the natural frequency and energy distribution of the drivetrain. According to the frequency characteristics, the potential resonance frequency is identified, and the dynamic response characteristics of the transmission chain are analyzed to determine the dangerous resonance frequency of the dynamic model.
Simulation of Multi-robot Cooperative Scheduling System Based on ROS
Authors: He Yiming , Quan Yanming
Published: November 2020

Aiming at improving the management and scheduling efficiency of multi-robot in warehouse environment, a simulation method based on ROS system using 3D model and virtual activities to realize multi-robot collaborative scheduling was proposed and a multi-robot cooperating and scheduling system based on ROS was established, which includes building multi-robot simulation model, designing warehouse simulation environment, building multi-robot architecture and communication, task allocation and scheduling based on the minimum cost method. The system has the functions of map building, automatic navigation and obstacle avoidance, as well as the optimal scheduling of multi-objective points. The simulation results showed that the multi-robot collaborative scheduling system can reduce the workload of managers and improve the work efficiency of multi-robot.
Mechanical structure optimization of energy storage tank group in MEES system
Authors: Zheng Xiaoming , Liu Lihua , Ren Aiping , Yu Yang , Zhi Shenglong
Published: November 2020

The energy storage component of the MEES system is mechanical elastic energy storage tank group. Whether the mechanical structure design of energy storage tank is reasonable or not directly determines the performance of the whole system. In this paper, the structural design scheme of series linkage energy storage tank group is proposed, which can take into account the energy storage capacity and power demand. Firstly, the structural group of energy storage tank group is analyzed. Secondly, the operation mode of energy storage and power generation process of energy storage tank group is described in detail. Finally, the mathematical model of energy storage/generation operation is established, which provides theoretical guidance for the configuration of capacity and power of energy storage tank group.
An Empirical Study on Transmission Performance of IPv6 over WAN Latency
Authors: Meijia Liu , Qing Zhang
Published: November 2020

Compared to IPv4, IPv6 provides more internet protocol (IP) addresses and higher security and has easier routing capability; and these advantages lead to tendency of the IP protocol used by a network to be upgraded from IPv4 to IPv6. With the global transmission requirements of Big Data increasing rapidly, wide area network (WAN) will play a crucial role in data transfer, but majority of previous research studies are limited to local area network (LAN). Therfore, in this study, a WAN experiment is implemented to estimate the transmission control protocol (TCP) throughput of IPv4 and IPv6, which is used as an index to evaluate the efficiency of data transmission. Four latest operating systems were tested to assess performance, and a pair of operating systems was chosen to estimate the transmission efficiency of WAN by time delay. In this experiment, performance degradation in latency was quantified. The results will be a useful reference for followup research in the future.
Dual-Wavelength Self-Similar Pulse Fiber Laser Based On Topological Insulator
Authors: Liu Weici , Qi Lei
Published: November 2020

Multi wavelength ultrashort pulse is of great significance in the scientific field. The dual-wavelength self-similar (SS) pulse mode-locked fiber laser with topological insulator (TI) is studied in this paper. The study on evolution of dual-wavelength SS pulse is based on Ginzburg-Landau equation (GLE) by split-step Fourier transforms (SSFT). The results have a high theoretical significance and value in practice.
Test Research on Vibration State of Transformer in High Speed EMU
Authors: Deng Hai , Shi Huailong , Qi Yayun
Published: November 2020

Transformers are important under-vehicle equipment for high-speed EMUs and play an important role in ensuring the power transmission of EMUs. This article first introduces the vibration reduction theory of the equipment under the EMU, and then briefly introduces the structure of the transformer and the arrangement of the measuring points. Afterwards, The vibration data of the transformer in the middle and late stages of wear are analyzed. It can be obtained that: some line sections of the vehicle have hunting movement, and the lateral acceleration of the frame has harmonics, the main frequency is 7Hz, and the amplitude is 0.6g (3-9Hz band-pass filter). The bogie vibration will be transmitted to the carbody and the equipment under the carbody, which has a greater impact on the vibration of the auxiliary converter body, that is, the lateral main frequency of the auxiliary converter is about 7Hz.
The Evaluation and Research of step profiler about the measurement uncertainty
Authors: Hu Chang’an , Yang Li , Lv Fei , Li Jieji , Zhao Tao , Wu Yu , Xue Liang
Published: November 2020

The step profiler has the advantages of excellent repeatability and high resolution. However, as a new contact measurement equipment, it has specific measurement errors. This paper proposes a novel method to evaluate a step profiler’s accuracy by measuring the nano grating standard structure. These standard step height and pitch samples are used in the measurement process. The samples’ morphological characteristics were obtained by Fourier transformation, phase modulation, and phase splicing of the sampled data. The experimental results show that the step profiler’s vertical and horizontal relative measurement uncertainty is 4.0% and 1.2%.
Application of Machine Vision Technology in Intelligent Manufacturing
Authors: Peng Chen
Published: November 2020

Machine vision technology refers to the use of computers to mimic human visual functions. In the simulation process, a part of the human brain function is also added. Information can be read from the image of the objective and analyzed and processed accordingly, which is widely used in machinery manufacturing. However, in practical applications, problems have arisen in which the application in the precise measurement of workpiece is not reasonable and the application of detection needs to be improved. This article will study its application in mechanical manufacturing, and give some opinions and suggestions on how to promote the application of machine vision technology in the intelligentization of mechanical manufacturing.
Research on Air Flight Simulation Control Law of Large Aircraft
Authors: You Junbin
Published: November 2020

The air flight simulator, also known as the variable stability aircraft, can make the dynamic characteristics of the machine change or simulate the response characteristics of different objects in a large range through the variable stability telex system. This paper is devoted to the research of the air flight simulation control law of large aircraft, and designs the five degree of freedom variable stability control law: to control the elevator, rudder and aileron of the basic aircraft, and to design the three-degree-of-freedom variable stability control law. The control of the direct lift surface and the automatic throttle was added, and the five-degree-of-freedom variable stability control law was designed to simulate the trajectory characteristics and velocity characteristics. Finally, the variable stability control law is verified based on the target aircraft simulator.
Research on influence of Web spacing of bogie side member on welding deformation
Authors: Liyana  , Suliang
Published: November 2020

In the production process of bogie, welding is one of the important production technologies. To study and control the welding deformation of bogie frame side beam to make the deformation value within a reasonable range has very important practical significance for the production of bogie side beam. The research content of this paper will take high-speed EMU bogie frame side beam as the research object. Set different web spacing, compare the welding deformation value, explore the influence of structural stiffness on the welding deformation of side beam, and use MATLAB software to curve fitting the welding deformation value, the research shows the distribution law of transverse, longitudinal, vertical and comprehensive welding deformation, and fits the mathematical equation between the web spacing L and longitudinal deformation SX, vertical deformation SY, transverse deformation SZ In this paper.
Classification Research on DEM Resolution Determination Method Based On Slope Topographic Factor
Authors: Su Dandan
Published: November 2020

The determination of optimum DEM resolution is helpful to improve the accuracy of the research results. The classification of DEM resolution based on topographic factor is studied. This paper classifies and expounds DEM resolution determination method from four aspects of "micro topographic factor", "macro topographic factor", "micro and macro composite slope topographic factor" and "slope topographic factor extension factor", which provides reference for the quantitative determination of optimal DEM spatial resolution in the future.
Study on seal of the hydraulic lock with high pressure-resistance and leakage-free
Authors: Qiao Jing , Wang Li Peng , Li Guo Qiang , Hou Ding Qi , Wang Xiang Ling
Published: November 2020

In order to solve the sealing problem between the two cavities of the servo actuator in harsh environment, the high pressure resistant hydraulic lock with integrated cone soft seal technology is designed by using nonmetal rolling molding and self-balanced technology of a integrated valve core. Its life and sealing effect were tested; the results showed that this new type hydraulic lock has reliable open and shut characteristic as well as reliable sealing effect. It can ensure the servomechanism is fully close anywhere. The new type design has been applied to certain model of carrier rocket.
Experimental and simulation analysis of the influence of moisture on dielectric and breakdown properties of insulation pressboard used in power transformer
Authors: Wen Hao , Cheng Lin , Jiang Yi , Zhao Zhigang , Ye Wenyu , Hao Jian
Published: November 2020

The influence of water molecules on cellulose has attracted much attention. The influence of water molecules on the dielectric property and breakdown property of cellulose requires in-depth research. In this paper, firstly, the effect of water on the dielectric spectrum in the frequency domain dielectric spectrum and the breakdown voltage of cellulose were studied. Then the parameters such as free volume, hydrogen bond, energy level and state density of cellulose under different moisture content were analysed by molecular simulation. The changes of dielectric properties and breakdown properties of cellulose under different water content were studied and summarized. The variation mechanism of dielectric property and breakdown property of different moisture content was explained by molecular simulation.
Laser thermal lens measurement based on Newton ring interferometry
Authors: Qi Lei , Huang Jinzhi , Zhan Shuyun , Liu Weici , Zhu Hongjie , Liu Yuwang
Published: November 2020

Thermal lens technology has attracted much attention because of its high sensitivity, low detection limit and being suitable for the analyses of minute samples. Thermal lens technology has been widely used in many fields, such as chemistry, physics, environmental monitoring, electronics, material science and life science. In this paper, the laser thermal lens measurement is studied based on Newton’s ring interferometry, especially for the case of low-power laser. The application of this method in the measurement of small samples is also discussed. It is helpful to study the micro deformation of thin film and lens under low power laser at room temperature. The results are very important for the future research on the micro deformation of optical elements.
Thermal design and optimization of the stratospheric airship equipment module
Authors: Ke Mei , Xueyin Sun , Yuanzhu Pu , Cheng Li , Xinying Li , Jingjing Di , Zhegui Hou
Published: November 2020

Stratospheric airship is a special air vehicle which suspended in the stratosphere for a long period of time, it can be used for military and civil investigation,observation, communication and other purposes to the Earth’s surface. Because its altitude is about 20 km,its thermal environment is different from normal aircrafts or spacecrafts. On the one hand,the solar heat flux during daytime and the heat source of the equipment require a good heat dissipation design of the airship;on the other hand,the radiation and convective heat exchange at night require a good thermal insulation design of the airship. The key thermal design of the airship is how to balance daytime heat dissipation and nighttime insulation. In this paper,the convective and radiative heat transfer model of a certain stratospheric airship is established based on the CFD simulation method,and the daytime and nighttime operating modes are analyzed. Three thermal design optimization schemes including compartmentalization,cooling holes, and fans are proposed and evaluated by simulation methods. The calculation results show that the thermal design margin in different operating modes of the airship can be effectively improved by controlling the fan operating, which provides a reference for future development of corresponding models.
Optimization of Monolithic Gilbert Cell Mixer for Frequency Band 935-960 MHz
Authors: Shi Daoling , Wang Jing
Published: November 2020

This paper presents the electrical and layout design and optimization of Gilbert Cell mixer for frequency band of 935-960 MHz with LO-frequency of 915 MHz. The obtained maximum conversion gain is 22.2 dB, IM3 is -11.5 dBm, and ICP is -25.5 dBm, respectively. The design consist of generic Gilbert Cell mixer with differential RF input and IF amplifier with differential output. The technology of choice is VTT08 with bipolar junction transistors (BJT).
A comparative study of several boundary conditions on the body surface for the meshless electromagnetic scattering method
Authors: Gao Yukun , Chen Hongquan , Xu Shengguan , Zhang Jiale , Cao Cheng , Gao Huanqin
Published: November 2020

In order to accurately calculate the radar cross sections (RCS) of stealth aircrafts by using the meshless method, several typical body surface boundary conditions from finite-volume time-domain (FVTD) methods, which are suitable for the meshless method, have been compared. The bistatic RCS of a 2-D cylinder irradiated by transverse magnetic wave (TM wave) or transverse electric wave (TE wave) and a 3-D sphere irradiated by different polarization waves are calculated by the meshless method based on different boundary conditions. The numerical results show that the bistatic RCS calculated by the first boundary condition is closest to the series solution, which indicates that the scattering electric field on the surface of perfect conductors is only related to the incident electric field, and the scattering magnetic field is related to the scattering magnetic field near the body surface and the variation of the normal scattering electric field on the body surface. Finally, based on the selected optimal body surface boundary condition, the paper present the electromagnetic scattering field and the bistatic RCS for a 3-D stealth aircraft model, which shows the ability of the meshless method in dealing with 3-D practical problems to a certain extent.
Pitch Control of Wind Turbines Based on BP Neural Network PI
Authors: Du Jing , Wang Bo
Published: November 2020

For wind turbine operating above the rated wind speed, the output power of the generator is maintained near the rated power through pitch control. Due to the non-linear relationship between the pitch angle and the wind speed, the traditional PI controller is not ideal for control above the rated wind speed. Therefore, the currently used PI controller generally incorporates gain scheduling technology. A wind turbine pitch controller based on BP neural network PI is proposed in this paper, which optimizes PI parameters and has better control effects. First, the PI control strategy with gain scheduling is briefly introduced, and then the principle and implementation steps of BP neural network PI are given. Finally, compared the control effects of the two control strategies of PI with gain scheduling and BP neural network PI, a new co-simulation between Simpack and MATLAB/Simulink is built, and it is proved that the BP neural network PI can improve the effect of pitch control.
Design of auto disturbance rejection control system for pneumatic manipulator based on PLC Technology
Authors: Xu Hang , Tian Jiule
Published: November 2020

Aiming at the coupling effect between joints of two degree of freedom pneumatic mechanism in reciprocating motion, and the reciprocating motion problem caused by the imprecision and jitter of dynamic model in high-speed motion, an auto disturbance rejection control system of Pneumatic Manipulator Based on PLC technology is designed, and the parameter model of flexible joint manipulator system is established, and the cubic spline interpolation is optimized by PLC technology, The effective control mode of operation space is realized. The correctness and stability of the active disturbance rejection control system of Pneumatic Manipulator Based on PLC technology are verified by simulation experiment.
Evaluation Model of Automobile Users Satisfaction Based on AHP
Authors: Li Lanyou , Lu Jingui
Published: November 2020

Aiming at the uncertainty problem of obtaining automobile users satisfaction, evaluation models which combine the objective evaluation methods such as entropy weight method(EWM) and the subjective evaluation methods such as analytic hierarchy process(AHP) are given. With power, fuel consumption, space, control, comfort, appearance, automotive interior and cost performance as the performance evaluation indicators, the comprehensive coefficient weight for each indicator is determined with both AHP and other objective evaluation methods. Taking the SUV users satisfaction as an example, the satisfaction corresponding to each model is given. The results show that the satisfaction evaluation model based on the combination of AHP and objective evaluation method is more effective, which provides a reference evaluation model for the automobile enterprises that make decisions or seek for design innovation.
Feature Extraction Method of Radiation Source in Deep Learning Based on Square Integral Bispectrum
Authors: Yao Yanyan , Yu Lu , Chen Yiming
Published: November 2020

The feature extraction method of radiation source based on deep learning is a hotspot of specific emitter identification research. In the selection of the initial radiation source data for feature extraction, there are mainly two kinds of time series IQ data and frequency domain bispectral data. Both the IQ signal and the signal bispectrum contain the information that can characterize the fingerprint of the radiation source, and the deep learning methods mostly use different deep network structures to obtain better classification performance. This paper proposes a feature extraction method of radiation source based on bispectral data, and designs a deep network structure combining convolution and long short memory network, which has a better classification and recognition rate than a single convolution network and a single LSTM network.
Study on Crack Propagation Characteristics of Pitch Bearing Based on Sub-model
Authors: Zhao Qiang , Du Jing , Huang Zong Ping
Published: November 2020

The pitch bearing is one of the key components of the wind turbine. The complex stress state, manufacturing process and harsh environment can all produce cracks that will lead to the final failure of the pitch bearing. Since there are few papers on cracked pitch bearings, the paper uses ANSYS and Franc3D co-simulation, and innovatively proposes a sub-model method to study the stress intensity factor and crack growth characteristics of the bolt hole defects of pitch bearings. From two aspects of crack length-depth ratio c/a and its propagation, the distribution of the stress intensity factor at the crack tip is explored. It is found that as the length-to-depth ratio c/a increases, the crack propagation trend gradually changes from extending along the crack length to the crack depth direction; as the crack propagation length increases, the intensity factor at the end of the crack surface is greater than that at the tip of the crack depth. The intensity factor indicates that when the crack expands to a certain size, the trend of crack growth along the surface is greater than the trend along the depth direction, and the propagation path is similar to the actual crack propagation path, which verifies the accuracy of the numerical simulation.
A Method Based on Functional Reconstruction of Product Innovation Design
Authors: Xi-qiang Yan , Yi-sheng Yang , Zong-zheng Liu
Published: November 2020

The purpose of product innovation design is functional innovative, and the functional reconstructed could be able to change the combination between product functions. First the product functional activities is used for functional modeling, then the model is checked with principles of functional modeling, After reduced functionality of the checked functional modeling under reduction rules, the function is expanded with expansion principles, Finally the new functional model is optimized with functional constraint, in order to build new products functional model and get product innovative solutions.
A teaching assistant system for big data analysis
Authors: Liu Pengfei , Chen Peidan , Yuan Yunling , Zhang Weifeng , He Xiaxu
Published: November 2020

With the rapid development of big data analysis, cloud computing and mobile computing, the demand of teaching auxiliary processing and students’ online learning in colleges and universities depends more and more on information system. According to the latest view of pedagogy, teaching evaluation is gradually turning to the "accompanying" education which is data-based and tracking the whole teaching process. In order to improve the current situation that the function of single teaching assistant system is limited, the information island caused by the expansion of multiple teaching auxiliary systems, and the situation that process data is not paid attention to, this research develops a complete educational administration and teaching auxiliary system, so as to promote the collection, processing and analysis of more, more detailed and higher frequency teaching real-time data.
Estimate method research at working life of wireless sensor network nodes
Authors: Chen D. M. , Dai X. N. , Tang Z. B.
Published: November 2020

Process deep research at disposable lithium sulfite chloride battery discharge characteristics and current-voltage characteristics when wireless sensor panel point working. Test the voltage-current time domain signal during the disposable lithium sulfite chloride battery discharge process and wireless sensor panel point working process through high precision power consume test instrument. Research and design one calculate method of wireless sensor panel point power consume. Build the estimate model for wireless sensor used battery power. Develop the wireless sensor network battery working life estimate and early warning method which based on the power consume calculate method of wireless sensor and wireless sensor used battery power estimate model, make users able to real time and accurately grasp all wireless sensor network panel point’s working life through this method, at the same time, can real time monitored whether battery of wireless sensor network panel points or the relate electric circuit of power supply exist problems, do well at wireless sensor panel point running and maintain works in advance. Finally, use high precision instrument process test and verify pulse voltage characteristics at wireless sensor panel point actual work which supply power by disposable lithium sulfite chloride battery, the test results are unanimous with theory research.
Fire Simulation Research on a Bus Based on Pyrosim
Authors: Zhang Jian , Tao Yiwen , Liu Xiaoying , Zhao Hao
Published: November 2020

Aiming at the problem of automobile fire simulation, a common model bus is taken as the research object, and the Pyrosim software is used as a tool to realize the fire simulation. In this study, Auto CAD was used to establish a three-dimensional bus model, and then it was imported into Pyrosim software, and Pyrosim software was used to simulate the fire of the bus model. Through research, it is found that the fire of a bus has its own characteristics, which can be divided into four stages: initiation, flashback, deflagration, and stability. According to the simulation results, the flue gas simulation analysis and thermal power analysis were done, and the simulation results were analyzed and discussed in depth. During the research, it was found that although the application of Pyrosim software has certain limitations in the simulation of automobile fire simulation, the research results can still provide a reference for automobile fire simulation and automobile fire prevention and control.
Design of Fungi Fermentation Cultivation System Based on Single-Chip Microcomputer
Authors: Zhong Lingling , Cao Jianan , Li Changkai
Published: November 2020

With the development of science and technology, the application field of fungi fermentation production is becoming wide than ever before. In view of the strict requirements of high-quality fungi fermentation on the cultivation environment, a fungi fermentation cultivation based on STC89C52 single-chip microcomputer is designed. The system uses STC89C52 single-chip microcomputer as the control unit. The sensor detects the temperature, humidity and alcohol content of the cultivation environment. Then the data is analyzed and adjusted by the single-chip microcomputer in real time. Thus, the temperature, humidity and alcohol content in the cultivation environment can be in the optimal range and the parameters control of cultivation environment is realized. The system can monitor and adjust the parameters of cultivation environment in real time and improve the efficiency and productivity of fungi cultivation through the preliminary test. It can be predicted that the comprehensive research of electronic science and technology and technique of microorganisms cultivation will inevitably become the important matter and research aspect in the future.
Deeplabv3+ semantic segmentation model based on feature cross attention mechanism
Authors: Zeng Haibo , Peng Siqi , Li Dongxiang
Published: November 2020

Aiming at the problem that the deeplabv3+ model is not accurate in segmentation of the image target edge, the image feature fitting is slow, and the attention information cannot be effectively used. It is proposed to add a feature cross attention module (FCA) to the model. The cross-attention network is composed of two branches and a feature cross attention module. Among them, the shallow branch is used to extract low-level spatial information, and the deep branch is used to extract high-level context features to make important feature extraction more refined. This paper designs and realizes the connection between Feature Cross Attention module and Deeplabv3+ coding module, input the output features of the Deeplabv3+ encoding module into the feature cross attention module for convolution operation to realize the recalibration of the original features. The decoding module of Deeplabv3+ obtains spatial features and channel features from two branches respectively, and then merges the obtained features to obtain more important features. The improved model was validated by the Pascal Voc2012 data set, and the results showed that the ratio of average intersection and the average pixel accuracy were increased by 1.96% and 2.84%, respectively. The model added with FCA can effectively improve the shortcomings of the original model, can segment the target more finely, and better solve the problem of rough segmentation boundary.
Research on the Applicability of Weather Forecast Model—Based on Logistic Regression and Decision Tree
Authors: Deng Feiyang
Published: November 2020

With the continuous development of meteorological technology, weather forecast has become an indispensable part of human in agriculture and life. Regardless of whether it is a climate forecast on rainfall in agriculture or a weather forecast on mobile phones or TV, a variety of climate forecasts bring great convenience to people’s production and life. For ordinary people, the prediction of whether it will rain the next day seems to be more practical. Many people determine the clothing and whether to bring an umbrella to go out for the next day by checking the weather forecast on mobile phones and TVs. It can be said that the prediction of rain directly affects people’s living habits. On such basis, this article studies the question of whether it will rain tomorrow in life. Based on about 140,000 meteorological data from the Australian Meteorological Bureau, this article studies and analyzes the influential effect of whether it will rain tomorrow by establishing a logistic regression and decision tree model, and sets up a prediction model to predict whether it will rain tomorrow.
Region-level Ride-hailing Demand Prediction with Deep Learning
Authors: Lan Ruohui
Published: November 2020

The exponential growth of ride-hailing demand has disrupted the urban transportation and changing the way people travel. To alleviate the shortage problem, many researchers have done numerous experiments to predict the region-level ride-hailing demand which can arrange the vehicles more efficiently. In this paper, we use the online ride-hailing order dataset of Haikou, Hainan Province, China, released by Didi Chuxing. We apply historical models, MLP, CNN and ConvLSTM model for region-level ride-hailing demand prediction in the next hour. Compared to the traditional deep learning models, ConvLSTM has a better performance with the lowest RMSE (4.796) when the input historical length is 24 hours.