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Transformer-CNN hybrid network for crowd counting

Journal of Intelligent and Fuzzy Systems 2024年第4期46卷 10773-10785页

作者： Yu, Jiamao Yu, Ying Qian, Jin Han, Xing Zhu, Feng Zhu, Zhiliang State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong University Jiangxi China College of Software East China Jiaotong University Nanchang China

Efficient feature representation is the key to improving crowd counting performance. CNN and Transformer are the two commonly used feature extraction frameworks in the field of crowd counting. CNN excels at hierarchically extracting local features to obtain a multi-scale feature representation of the image, but it struggles with capturing global features. Transformer, on the other hand, could capture global feature representation by utilizing cascaded self-attention to capture remote dependency relationships, but it often overlooks local detail information. Therefore, relying solely on CNN or Transformer for crowd counting has certain limitations. In this paper, we propose the TCHNet crowd counting model by combining the CNN and Transformer frameworks. The model employs the CMT (CNNs Meet Vision Transformers) backbone network as the Feature Extraction Module (FEM) to hierarchically extract local and global features of the crowd using a combination of convolution and self-attention mechanisms. To obtain more comprehensive spatial local information, an improved Progressive Multi-scale Learning Process (PMLP) is introduced into the FEM, guiding the network to learn at different granularity levels. The features from these three different granularity levels are then fed into the Multi-scale Feature Aggregation Module (MFAM) for fusion. Finally, a Multi-Scale Regression Module (MSRM) is designed to handle the multi-scale fused features, resulting in crowd features rich in high-level semantics and low-level detail. Experimental results on five benchmark datasets demonstrate that TCHNet achieves highly competitive performance compared to some popular crowd counting methods. © 2024 – IOS Press. All rights reserved.

关键词： Feature extraction

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A Coupled Simulation Model of the Anode Erosion Process under Vacuum High-Frequency Inrush Current 7

A Coupled Simulation Model of the Anode Erosion Process unde...

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7th International Conference on Electric Power Equipment - Switching Technology, ICEPE-ST 2024

作者： Zhang, Wenxin Yu, Yongxiang Qiu, Nengfei Zuo, Wen Yao, Daojin East China Jiaotong University State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure Nanchang330013 China

ISBN: (纸本)9798350388947

The process of anode erosion exerts a profound effect on the cessation of high-current vacuum arcs. The objective of this paper is to conceptually explore the process of anode surface erosion caused by the combined influence of high-frequency inrush current energy flow density and arc pressure. Using a pure copper anode with a radius of 20mm, a model was established to study the erosion of the anode area due to the impact of high-frequency inrush currents in a vacuum interrupter, using the equivalent arc energy of a typical high-frequency inrush current with a peak of 20 kA and a frequency of 4250 Hz within 2 ms as conditional input. Using the moment when the current crosses zero as the reference point. The results indicate that significant erosion occurs on the anode surface due to the combined effects of inrush energy flow density and the arc pressure generated by the high-frequency inrush current. After 0.3 ms of arc discharge, the temperature reaches the fusion temperature of the anode and forms a molten pool, and the liquid metal begins to flow. Consequently, the maximum temperature of the anode surface did not stay centered on the anode surface. © 2024 IEEE.

关键词： Anodes

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High-speed train positioning based on a combination of Beidou navigation, inertial navigation and an electronic map

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Science China(Information Sciences) 2023年第7期66卷 237-252页

作者： Hui YANG Shuai-Qiang DONG Chun-Hua XIE School of Electrical and Automation Engineering East China Jiaotong University Key Laboratory of Advanced Control & Optimization of Jiangxi Province East China Jiaotong University State Key Laboratory of Performance Monitoring Protecting of Rail Transit Infrastructure East China Jiaotong University

To date, the studies on the combination positioning of high-speed trains have made great progress, but the positioning accuracy of these methods is relatively low. Map-matching positioning can improve positioning accuracy, but information transmission is time-consuming. Few studies incorporate it into combination positioning. To solve the problem, this paper proposes a high-speed train positioning method based on combining a Beidou navigation system, an inertial navigation system, and an electronic map. First, the combination positioning problem is transformed into a multi-objective optimization problem, which weights the direction similarity and distance error to form a fitness function and converts the railway line and the maximum error range of each positioning system into constraints. Second, an improved differential evolution algorithm is proposed to solve this problem. By referencing the gray wolf algorithm,the differential evolution algorithm updates individuals by varying toward the direction of multiple optimal values. Then, a new combination positioning algorithm for high-speed trains is proposed. In the simulation,the increase in positioning speed and accuracy is analyzed and validated. Compared to the current algorithms, the proposed algorithm performs better. The proposed method has practical value for improving the reliability and safety of train operations.

关键词： electronic map multi-objective optimization differential evolution algorithm Beidou navigation system high-speed train positioning

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Current-carrying tribological behavior of C/Cu contact pairs in extreme temperature and humidity environments for railway catenary systems

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Science China(Technological Sciences) 2024年第8期67卷 2537-2548页

作者： SHEN MingXue JI DeHui HU Qiang XIAO Li LI QiuPing State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013China School of Materials Science and Engineering East China Jiaotong UniversityNanchang 330013China Institute of Applied Physics Jiangxi Academy of SciencesNanchang 330095China

Many current-carrying contact pairs, such as those found in pantograph-catenary systems, operate in open environments and are susceptible to significant external interference from temperature and humidity variations. This study investigated the evolution of the friction coefficient and contact resistance of C/Cu contact pairs under alternating temperature, humidity, and current conditions. Through experimentation, the wear rate and microtopography of the worn surface were analyzed under various constant parameters. Subsequently, the differences in tribological behavior and current-carrying characteristics of the contact pairs under these three parameters were explored. The results revealed that the decrease in temperature resulted in a significant increase in the friction coefficient of the contact pairs, carbon wear, and copper surface roughness. Additionally, the surface oxidation rate was lower at lower temperatures. Moreover, contact resistance did not consistently increase with decreasing temperature, owing to the combined action of the contact area and the oxide film. Compared with temperature, humidity fluctuations at room temperature exerted less influence on the friction coefficient and contact resistance of the contact pairs. Dry environments rendered carbon materials vulnerable to oxidation and cracking, while excessive humidity fostered abrasive wear and arcing. High-current conditions generally degraded the tribological properties of C/Cu contacts. In the absence of current, the friction coefficient was extremely high, and the copper transfer was high. Under excessive current, copper was susceptible to plowing by carbon micro-bumps and abrasive particles, resulting in a decrease in the friction coefficient. The release of lipids from the carbon surface due to temperature elevation weakened the electrical contact performance and increased the occurrence of arc erosion, thereby exacerbating carbon wear.

关键词： temperature/humidity pantograph-catenary system C/Cu wear current-carrying friction sliding electrical contact

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Model-free adaptive robust control method for high-speed trains

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Transportation Safety and Environment 2024年第1期6卷 93-102页

作者： Zhongqi Li Liang Zhou Hui Yang Yue Yan School of Electrical and Automation Engineering East China Jiaotong UniversityNanchang 330013JiangxiChina State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013JiangxiChina

Aiming at the robustness issue in high-speed trains(HSTs)operation control,this article proposes a model-free adaptive control(MFAC)scheme to suppress ***,the dynamic linearization data model of train system under the action of measurement disturbance is given,and the Kalman filter(KF)based on this model is derived under the minimum variance estimation ***,according to the KF,an anti-interference MFAC scheme is *** scheme only needs the input and output data of the controlled system to realize the MFAC of the train under strong ***,the simulation experiment of CRH380A HSTs is carried out and compared with the traditional MFAC and the MFAC with attenuation *** proposed control algorithm can effectively suppress the measurement disturbance,and obtain smaller tracking error and larger signal to noise ratio with better applicability.

关键词： automatic train operation(ATO) model-free adaptive control(MFAC) disturbance suppression minimum variance estimation Kalman filtering(KF) partial format data model

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Effect of powder feeding rate and size on critical velocity and mechanical properties of cold sprayed Al_(2)O_(3)/2024 deposit

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Chinese Journal of Aeronautics 2024年第12期37卷 544-559页

作者： Dong WU Jiaju ZHANG Yu SU Wenya LI Yaxin XU Xiawei YANG Chunjie HUANG School of Materials Science and Engineering East China Jiaotong UniversityNanchang330013China State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Friction Welding Technologies Northwestern Polytechnical UniversityXi’an 710072China

The particle acceleration behavior and deposition mechanism of cold spraying aluminum matrix composites(Al_(2)O_(3)/2024)are complicated by the addition of ceramic *** effects of different feeding rates and particle diameters on critical velocity and mechanical properties were studied by numerical simulation and *** results indicate that as the powder feeding rate increases,the impact velocity of gas and particles gradually decreases,and the temperature of gas and particles increases,resulting in an increase in the difference between particle impact velocity and critical *** highest tensile strength of the deposit is achieved at a powder feeding rate of 1 r/min,which is 343 *** the powder feeding rate increases,the performance of the deposits decreases,but it significantly saves time and *** the particle diameter increases,the impact temperature first increases and then decreases,resulting in the critical velocity first decreasing and then increasing,and the mechanical performance first increasing and then *** some extent,the best performance of the deposit is achieved when the size of the metal particle is close to that of the ceramic particle.

关键词： Cold spray Aluminum matrix composites Critical velocity Feeding rate Particle size Mechanical property

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Wind power forecasting based on improved variational mode decomposition and permutation entropy

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Clean Energy 2023年第5期7卷 1032-1045页

作者： Zhijian Qu Xinxing Hou Wenbo Hu Rentao Yang Chao Ju State Key Laboratory of Performance Monitoring Protecting of Rail Transit Infrastructure East China Jiaotong University330013JiangxiChina College of Electrical and Automation Engineering East China Jiaotong University330013JiangxiChina

Due to the significant intermittent,stochastic and non-stationary nature of wind power generation,it is difficult to achieve the desired prediction ***,a wind power prediction method based on improved variational modal decomposition with permutation entropy is ***,based on the meteorological data of wind farms,the Spearman correlation coefficient method is used to filter the meteorological data that are strongly correlated with the wind power to establish the wind power prediction model data set;then the original wind power is decomposed using the improved variational modal decomposition technique to eliminate the noise in the data,and the decomposed wind power is reconstructed into a new subsequence by using the permutation entropy;with the meteorological data and the new subsequence as input variables,a stacking deeply integrated prediction model is developed;and finally the prediction results are obtained by optimizing the hyperparameters of the model algorithm through a genetic *** validity of the model is verified using a real data set from a wind farm in north-west *** results show that the mean absolute error,root mean square error and mean absolute percentage error are improved by at least 33.1%,56.1%and 54.2%compared with the autoregressive integrated moving average model,the support vector machine,long short-term memory,extreme gradient enhancement and convolutional neural networks and long short-term memory models,indicating that the method has higher prediction accuracy.

关键词： wind power prediction improved variational mode decomposition permutation entropy stacking deep learning

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Piecewise model-based adaptive compensation control for high-speed trains with unknown actuator failures

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Transportation Safety and Environment 2023年第4期5卷 172-181页

作者： Chang Tan Junhui Zhang Hui Yang Leilei Zhang School of Electrical and Automation Engineering East China Jiaotong UniversityNanchangJiangxi 330013China State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure NanchangJiangxi 330013China

In order to deal with the uncertainties caused by different operation conditions and unknown actuator failures of high-speedtrains,an adaptive failures compensation control scheme is designed based on the piecewise model.A piecewise constant model is introduced to describe the variable system parameters caused by the variable operation environments,and a multiple-particle plecewise model of high-speed trains,with unknown actuator failures,is then *** adaptive failure compensation controller is developed for the multiple-particle piecewise constant model,by using a direct model refering to the adaptive control *** an adaptive controller can not only compensate the uncertainties from unknown actuator failures,but also effectively deal with the uncertainties caused by different operating ***,a CRH380A high-speed train model is taken as the controlled object for the simulation *** simulation results show that the proposed controller ensures the desired system performance in the presence of unknown actuator failures and uncertain operation conditions.

关键词： actuator failures adaptive compensation piecewise model high-speed train multiple-particle model

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Helical streamers guided by surface electromagnetic standing waves

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Plasma Science and Technology 2023年第7期25卷 1-5页

作者：邹丹旦涂忱胜崔春梅 State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013Peopleʼs Republic of China School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072Peopleʼs Republic of China

The streamer that is driven by the specific pulse DC discharge parameters can stably form a three-dimensional helical plasma channel in a long dielectric tube in the low-temperature plasma experiment,in cases when there were neither external background magnetic field or other factors that destroyed the poloidal symmetry of the *** formation mechanism and chirality of helical streamers are discussed according to the surface electromagnetic standing wave *** shape of the helical streamers and the characteristics of helical branches are quantitatively analyzed to further expand the application of plasma and streamer theory in the helix problem and chiral catalytic synthesis.

关键词： low-temperature plasma streamers surface electromagnetic standing wave helix

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Tribochemistry of alcohols and their tribological properties: a review

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Frontiers of Materials Science 2023年第1期17卷 111-128页

作者： Liping Xiong Xiaoya Sun Qi Chen Mengyue Zhu Zhongyi He Lili Li School of Materials Science and Engineering East China Jiaotong UniversityNanchang 330013China Jiangxi Railway Transit Key Materials Engineering Technology Research Center Nanchang 330013China State Key Laboratory of Rail Transit Infrastructure Performance Monitoring and Guarantee East China Jiaotong UniversityNanchang330013China

Recently,alcohols have attracted more attention due to their excellent tribological performance,especially superlubricity under low *** solution,as a liquid lubricant,can easily reach the superlubricity state under low loads because of the formed low shear hydroxylation interfaces induced by the tribochemical reactions.A general picture and its influencing factors have been elucidated,not only at the macroscopic scale but also at the nanoscale,which is sufficient to provide effective guidance for lubrication design and tribology research in ***,we provide a review on the recent applications of alcohols in *** addition,the material transformation caused by alcohols in friction is a key factor affecting the tribological *** an important two-dimensional material,the growth mechanisms of graphene are variable,and the most famous is the formation of carbon radicals under the action of metal ***,based on the formation mechanism of carbon friction film(such as amorphous carbon and graphene),the main content of this review also includes the transformation of graphene in alcohol solution friction process.

关键词： alcohol tribochemistry graphene carbon-based material

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