bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic characteristics analysis of nonlinear suspension system of automobile with seven degree of freedom
Authors: Jia Hongyu , Yun Chao , Wang Ying 
Published: September 2019

Abstract
The application of MATLAB/SIMULINK to establish the mechanical simulation model of seven-degree-of-freedom vehicle linear and non-linear suspension system. Realization of system response under simulated road excitation, the dynamic characteristics of the non-linear suspension are studied, the non-linear spring and damping are simulated, and the parameter ε is introduced to change the degree of nonlinearity. The root mean square values of acceleration and displacement of linear suspension, non-linear stiffness suspension and non-linear damping suspension are analyzed and compared under different pavement conditions. The results show that: The mean square root of the acceleration of the body mass center and the pitch angle of the non-linear suspension are reduced by 14.3% and 17.0% respectively compared with the linear acceleration of the body mass center and the pitch angle; The root mean square value of pitch acceleration of non-linear suspension damping is 31.2% less than that of linear acceleration, which improves ride comfort and safety to a certain extent.
Heat transfer characteristics in channel with square rib at different Mach numbers
Authors: Li Heng , Wang Duo , Yu Ting , Xu Hongyi 
Published: September 2019

Abstract
The detailed flow structures and closely-related heat transfer characteristics were investigated along the wall of a cooling channel with rib tabulator by computation. The two-dimensional Navier-Stokes equations were solved using the density-based algorithm and strongly-coupled with the heat-transfer equation. Three typical Reynolds numbers defined by rib height and Mach numbers were set at 500, 750, 1000 and at 0.2, 0.3, 0.4, respectively. Results show that, As the Mach numbers changing from 0.2 to 0.4, the local Nusselt numbers increase and the average heat transfer effects are enhanced. Based on the instantaneous field of vortices evolvement, the vortexes are first generated near the top surface of the rib by the strong shear effects. Then the vortexes are shed and intensified gradually downstream. Particularly, an important phenomenon is, for the first time, discovered that the high Nusselt number has a consistent correlation with the positive and negative sign alteration of the shear layer on the wall, which satisfactorily explains the mechanisms of heat transfer enhancement due to the flow.
Obstacle contour extraction method based on improved Grabcut algorithm
Authors: Mao Jiateng , Hu Yueli 
Published: September 2019

Abstract
Obstacle distance measurement has an important role in the design of mobile robots, which allows the robot to timely complete the movement steering to avoid damage caused by crushing. The accurate segmentation and edge detection of the target obstacle in the image is the premise of completing the measurement. In this paper, based on the classification and location of specific obstacles, a method of obstacle segmentation based on improved Grabcut algorithm is proposed, and the edge contour is extracted by Canny operator. The method classifies the image’s background pixels using a Laplacian Mixture Model and modifies the covariance matrix to change the probability density function of that model, thereby reducing the misclassification probability of the pixels. In addition, the method crops the input image in advance to reduce the running time of the algorithm. This paper also introduces a way to initialize the image’s Trimap, considering the visual angle of the sweeper. The above four improvements enable the method to accurately segment obstacle targets and extract contour curves. The accuracy of the method and the good real-time performance on the embedded platform are verified by comparison experiments.
Design of the desktop vapor polisher with acetone vapor absorption mechanism
Authors: Xu Kaiwen , Xi Tao , Liu Chunrong 
Published: September 2019

AbstractAcrylonitrile butadiene styrene (ABS) parts fabricated by fused deposition modeling (FDM) usually have high surface roughness due to the stair-step effect. The vapor smoothing method gives ABS parts a smooth and shiny appearance. However, the organic solvents used for vapor smoothing such as acetone could be toxic to operators. This paper proposed the design of a desktop vapor polisher with acetone vapor absorption mechanism. It prevents acetone vapor from leaking into the outside environment during the smoothing process in a technically feasible and economical way by using water. The polisher also includes other innovations such as the modular design and induction heating method. The benefits of the design include environmental friendly, economy saving, energy saving and user friendly. Finally, a full-scale model has been made to illustrate the layout of the design, and verification experiments have been done with a miniature prototype.
Design of an application which computes the Bistatic coverage zone for The Republic of Cabo Verde
Authors: Lopes Dias Ricardo Yannick Cabral , Liu Tao 
Published: September 2019

Abstract
The purpose of this paper is to design an application which can compute the bistatic system coverage zone for the archipelago of Cabo Verde, where a specific study of bistatic geometry was made. From its triangular configuration, known as bistatic triangle (transmitter, target, receiver), we obtained the parameters, and subsequently, the equations necessary to obtain the Oval of Cassini that delimits the coverage zone that it guarantees. The direct synchronization method was chosen, and the line of sight between transmitting and receiving antennas was required, permitting us to measure the distances from the transmitter to the target and from the target to the receiver. After obtaining all the theoretical validities, a tool was created, for the user to choose the positions of the antennas. Then, the software will paint the coverage zone with the qualities index required in accordance with the chosen data and technical parameters.
Propagation characters of PD UHF signal in a prefabricated joint of XLPE cable
Authors: Wang Luliang , Yang Xu , Cheng Lin , Fu Fangda , Jiang Yi , Pan Zijun 
Published: September 2019

AbstractInvestigating the propagation characters of UHF partial discharge (PD) signals in cable joint is helpful to the application of UHF method in XLPE PD monitoring. In this paper, a propagation model about UHF signal in a prefabricated joint is constructed. Based on it, it effects of some factors, i.e. longitudinal distance of detection location, lateral location of detection, detecting angle, pulse width, pulse amplitude, the size of metal shield and the thickness of semiconductive layer, on the PD signal propagation are studied. It is found that the signal amplitude decays faster in the joint than that in the body, and the signal intensity is much stronger inside the metal shield than that outside. The maximum amplitude of electromagnetic wave radiated by the PD source appears in the radial direction along the radius of the cross-section. The short duration of discharge pulse contributes to the appearance of high-order modes, while the response signal is proportional to the PD source. The metal shield and semiconductive layer increase the signal attenuation. These results provide insight into some design parameters of UHF antenna and its installation location.
Effect of absorbing materials on shielding effectiveness of incomplete cavity
Authors: Chen Xin , Huang Xuegong 
Published: September 2019

Abstract
With the deterioration of electromagnetic environment, the electronic devices are seriously affected by the electromagnetic interference in high frequency, which makes it especially important to find protective methods. In this paper, a wireless transmission equipment was taken as an example to analyze the effect of absorbing materials on shielding effectiveness of cavity by numerical simulation. The results show that the absorbing performance is little affected by the position of absorber, but greatly affected by the direction. Furthermore, absorbing materials can effectively reduce the electromagnetic coupling of penetrating wire and increase the shielding effectiveness at resonant frequencies, but have little effect on interference transmitted by conduction, which indicates that the absorbing materials is an effective but deficient solution for electromagnetic protection of electronic equipment with complete circuit.
Research on IPMSM position decoupling control without filter
Authors: Li Wu , Chen Jing 
Published: September 2019

Abstract
In this paper, a new method of decoupling sensorless and filterless IPMSM (Interior permanent magnet synchronous motor) high frequency square wave is proposed, which is a new method of decoupling the rotor position of the motor and forming a stable control system by injecting high frequency square wave into the static shafts and computing the signal delay. Due to the high frequency square wave injection method, the influence of rotor resistance is reduced and the estimation accuracy is improved. At the same time, the decoupling method without filter is adopted to avoid filter interference and improve system bandwidth. In this paper, a better observer than PI observer is adopted, so that the system estimation accuracy is higher and the anti-interference performance is stronger. Finally, the simulation is realized by matlab.
Quantifying the harmonic impact for multi-harmonic sources
Authors: Tan Meng , Li Yaqiong , Geng Xiaohong , Wen Jun 
Published: September 2019

Abstract
Accurately dividing the harmonic impact of each harmonic source on the PCC bus is an important prerequisite for implementing the ‘reward and punishment scheme’. At first, the equivalent circuit model of multi-linear load harmonic source in PCC bus is obtained by using circuit theory, and the method of quantifying the harmonic impact for multi-harmonic sources is derived. Secondly, the M-estimated robust regression method is introduced into quantifying the harmonic impact for multi-harmonic sources. The method uses the iteratively weighted least squares iterative method to solve the regression coefficients, and calculates the harmonic impact of each harmonic source in the multi-harmonic source system according to the regression coefficient. In order to verify the effectiveness of the method, the simulation analysis is carried out in the power system analysis software ETAP. The results show that the method can effectively evaluate quantifying the harmonic impact for multi-harmonic sources.
Design of monitoring system for marine power station based on DSP
Authors: Li Neng , Wu Zhiliang 
Published: September 2019

Abstract
Based on the experimental platform of marine power station, the design of the collection circuit was presented and the electrical parameters such as voltage, current, frequency and phase were collected by taking digital signal processor (DSP) in type of TMS320F2812 as the core controller. As regards the site jamming signal existed in power system, the full-wave differential Fourier algorithm was applied to improve the sampling process. It could completely eliminate the DC component and suppress the aperiodic component, while obtaining the accurate fundamental component. Furthermore, the necessary conditions for establishing an effective monitoring system were provided. Combined with the touch screen in type of WEINVIEW MT8100i, the data monitoring and alarm display of the marine power station were realized. The designed data collection and monitoring system can be continuously and stably operated on the experimental platform, which verifies the feasibility of the design.
The Electrical and mechanical simulation and computer-aided geometric optimization of high voltage post-insulator based on RBF neural network and finite element method
Authors: Zhang Shiling 
Published: September 2019

Abstract
The High-voltage post insulators are widely used in power systems. The electrical and mechanical properties of post insulators are closely related to the operation stability of power system. Based on the three-dimensional finite element method (FEM), the mechanical and electrical properties of post insulator are modeled and analyzed. The results show that the maximum electric field strength of the insulator is located on the surface of the voltage-equalizing ring near the high voltage side, and the first principal stress maximum value of 150MPa is mainly concentrated on flange supporting side. The PSO-RBF hybrid algorithm is proposed to optimize nonlinear inversion structural parameters of the post insulator. The results show that the PSO-RBF neural network has good effect on the nonlinear fitting mapping of the original finite element calculation data, and the algorithm has good convergence. The mechanical and electrical properties of the post insulators and the configuration of the post insulator-related voltage sharing ring and shielding ring are obtained, which can provide the theoretical basis for the insulation structure design and fittings configuration of UHV and below post composite insulators.
Simulation study on commutation failure control and recovery of UHVDC with hierarchical connection mode
Authors: Wang Sichao , Wen Jun , He Dongshan , Geng Xiaohong 
Published: September 2019

Abstract
UHVDC transmission projects with hierarchical receivers are connected in series on the DC side. When a single voltage level of AC system fails, commutation failure may occur in both hierarchies of DC system, and the impact will be more serious when the electrical connection is strong. In the process of fault recovery, inappropriate control strategy will also lead to successive commutation failures. In this paper, a commutation failure control and recovery strategy based on real-time fault detection and determination is proposed. In view of the instantaneous faults of AC system, the starting time is determined according to the predicted results of commutation failure, so as to reduce the starting times and prevent the continuous commutation failure in the recovery process. When the single-hierarchy AC system is permanently severely faulted, the fault hierarchy is isolated and the non-fault layer operates normally. The PSCAD/EMTDC simulation model of an UHVDC transmission project is built. Instantaneous and permanent faults are set up to simulate. It is verified that the proposed strategy can effectively reduce the number of successive commutation failures and improve transmission reliability.
An approach for constructing the S-box using the CML system
Authors: Liu Liyan , Lei Zhiyi 
Published: September 2019

Abstract
We propose an approach for constructing S-box by using the CML chaotic system. The chaotic sequences produced by the CML chaotic system are used to permute and diffuse the elements of the S-box randomly. The obtained S-box has a strong randomness property due to the high dimensional feature of the CML chaotic system. We analyze bijective property, nonlinearity, strict avalanche criterion, outputs bit independence criterion, input/output XOR distribution and linear approximation probability of the constructed S-box. The experimental results show that the proposed approach for constructing S-box is effective.
Lens rim points stitching algorithm based coaxial alignment micro assembly
Authors: Zhang Heng , Ye Xin , Yu Xinhai , Shao Chao , Wu Feifei , Zhao Yijin , Wang Lei 
Published: September 2019

Abstract
Optical lens assemblies are used more and more widely, and assembly and alignment processes are key to affecting lens accuracy. Considering that the common way of assembling lenses was manual, the coaxial alignment for intermediate-scale parts was considered to be a good alternative, which could improve the accuracy of assembly effectively. But it was difficult to capture the full edge of the lens in one image because of the limit of the CCD camera field of view. To solve this problem, a rim points stitching algorithm was proposed, and the barrel and lens were imaged by the camera at three different position. After the rim points were extracted from the three images, all the rim points were stitched according to the position of the camera at three locations. The rim points stitched were fitted to two circles by using the least squares method. Finally, according to the adjustment algorithm, the adjustment amount of the lens with respect to the lens barrel was calculated. Experimental results showed that this method could align lenses with the diameter greater than 60mm. The technique has the potential to be applied in automated alignment of lens assemblies.
Research on unbalanced training samples based on SMOTE algorithm
Authors: Li Kai , Hu Yueli 
Published: September 2019

Abstract
In the classification tasks of deep learning, unbalanced data distribution of training samples is a serious problem. In this case, the deep neural networks will bias to the majority-class samples and can not learn data characteristics of the minority-class samples well, making it difficult to identify the minority-class samples. To improve the performance of deep neural networks on minority-class samples, this paper proposes a novel scheme based on SMOTE algorithm, which generates new minority-class samples to balance the training dataset. Compared with the traditional over-sampling operations commonly used in image classification tasks such as copying images simply, image flipping, color adjustment etc, our scheme generates new minority-class samples, which improves the features of minority-class samples and avoids the over-fitting problem in classification. The workflow of image preprocessing and SMOTE over-sampling operation are introduced in this paper. The selection basis of the network model and the comprehensive model indicators are also presented. Comparative experiments are performed by testing models trained respectively on unbalanced dataset and balanced dataset after SMOTE over-sampling operation. Results shows that the proposed scheme is feasible and effective to improve the neural network’s ability of identifying minority-class samples in classification tasks.
An embedded wide-band sensor for PD on-line monitoring of XLPE cable joint
Authors: Fu Fangda , Yang Xu , Cheng Lin , Wang Luliang , Zhang Jing , Pan Zijun 
Published: September 2019

AbstractMonitoring partial discharge (PD) activities in the joint of cross-linked polyethylene (XLPE) cables has attracted much attention due to its extensive application and high fault rate. In this paper, we designed a wide-band sensor with simple configuration, which was embedded in the outer semi-conductive layer of the cable. Based on the analysis of circuit and antenna models, the structural parameters of sensor were determined, and it was found that the effective bandwidth reached up to 500 MHz. In addition, the sensor had a quick response to the pulse with a rising time longer than 2 ns by testing its square response, as well as a linear input-output characteristic and a sensitivity of 3 pC. At last, the sensor was applied to insulation defect type identification in the cable joint. As for three common defects, both the single PD pulse and PD patterns showed distinct. These indicated that the sensor had a potential application prospect in the PD online detection for cable joint.
A real-time gas turbine simulation model for control logic evaluation
Authors: Tao Ye , Pan Yining , Xin Xiaopeng , Xu Yunbing , Sui Yongfeng 
Published: September 2019

Abstract
During our development of a gas turbine control system, we need to evaluate the correctness and completeness of the control logic before conducting a hardware-in-the-loop (HIL) test. For this purpose, a pure software simulation framework which includes virtual DPU (VDPU) and gas turbine model interfacing through OPC protocol was proposed. A real-time gas turbine simulation model for this framework was developed. This gas turbine model was written in C++ and employs the object-oriented philosophy for maintenance and further development and it uses a non-iterative method to ensure the real-time capability to run simultaneously with the control logic. From the result of preliminary tests on this model, it shows to be able to simulate the response of real gas turbine to the instructions from the control system and suitable to evaluate the control logic.
A study on reducing power consumption of the centrifugal fan for the negative pressure adsorption wall climbing robot
Authors: Yang Yongkai , Zhang Hu , Song Qiuzhi 
Published: September 2019

Abstract
In order to solve the problems of ship wall climbing robot’s great power consumption and high noises, a new approach to reducing power consumption and noises of the centrifugal fan was investigated. Firstly, the relationship between the air volume of a centrifugal fan and ship’s dip angle of the outer wall is obtained by analyzing force condition of the robot and the theory of negative pressure adsorption. Furthermore, by means of researching the process of fan’s speed-regulation through changing DC 0-3.3 of fan’s driver. We get the relationship between speed-regulation voltage after D/A convert of fan’s driver and ship’s dip angle of the outer wall. We proposed a control system that can automatically detect ship’s dip angle of the outer wall and adjust the output power of the centrifugal fan. Finally, the result of reducing power consumption and noises was tested effectively.
Influencing factors of water recycle device in cooling tower of thermal power plant based on corona discharge principle
Authors: Zhang Mingkun , Wang Yinyi , Liu Jieyu 
Published: September 2019

Abstract
The water loss in the wet cooling tower of thermal power plants is serious. There is a lack of high-efficiency recycling method for water mist with a small particle size until now. Based on the principle of electrostatic deposition, this paper analyses the principle of water mist recovery based on corona discharge. The water recovery device based on corona discharge was designed. The equivalent flow model was used to calculate the ion flow field distribution in the device, and the influence of the size of the water collecting plate on the ion flow field was analysed. By using the finite element analysis (FEA), the influence of the shape of the water collecting plate and the structure of the discharge electrode on the electric field in the device is calculated. A device optimization program is proposed. The results of this study provide theoretical guidance for the recycle of water mist in thermal power plant cooling towers.
Comparison between suppressing approaches of very fast transient over voltages in gas insulated substation
Authors: Almenweer Reem A , Su Yixin , Wu Xixiu 
Published: September 2019

Abstract
Very Fast Transient Over-Voltage (VFTO), which is a unique electromagnetic transient phenomenon generated by SF6 gas discharge in disconnector gap in Gas Insulated-Substation (GIS), could bring damage to power devices, especially to power transformers. The peak magnitude and high-frequency oscillations of VFTO cause reduction of dielectric of gas insulation, high inter-turn voltages and internal resonance in the transformer windings. Due to all of these disadvantages related to VFTO, VFTO becomes a criterion to determine the insulation level of the GIS, and VFTO damping is rising as an essential issue to be solved. However, the researchers concern on finding the optimum technique for suppressing VFTO, this paper aims to discuss the most feasible methods for mitigation of the overvoltage magnitude of VFTO and determine the most efficient approach for VFTOs attenuation by presenting the advantages and disadvantages of each approach. In this review paper, some suppression methods of very fast transients in GIS are presented, including adopting a resistor-fitted disconnector, ferrite rings, surge arresters, and high-frequency resonator. The results show that the peak value of VFTOs can be decreased to a great level by employing the proposed damping methods. Finally, the best approach for the suppression of VFTOs is chosen based on deep discussion for each method with its features.