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A comparison on the effects of coal fines and sand fouling on the shear behaviors of railway ballast using large scale direct shear tests

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Journal of Traffic and Transportation Engineering(English Edition) 2025年第1期12卷 52-67页

作者： Xu Zhang Shunying Ji Yang Feng Yongjun Li Chunfa Zhao School of Civil and Transportation Engineering Guangdong University of TechnologyGuangzhou 510006China State Key Laboratory of Rail Transit Vehicle System Southwest jiaotong UniversityChengdu 610031China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

Railway ballast is easily contaminated by different fouling material and the fouled ballast always causes the deterioration of railway *** previous studies focused on the effect of a certain kind of fouling material on ballast performance,but few studies compared the influence of different fouling *** paper presents a series of direct shear tests on the clean ballast and the fouled ballast mixed with coal fines or sand to understand the effects of different fouling material.A unified empirical model is proposed to well capture the shear stress-displacement responses of the clean and fouled *** equations are also obtained to characterize the variation of the nonlinear shear strength envelope of the fouled ballast with the fouling *** on these equations,a simple method is proposed to predict the shear strength of the fouled ballast using the shear test results of clean *** measured results demonstrate significant differences between the effects of coal fines and sand on the shear behaviors of ballast,to which particular attention should be paid in order to take targeted maintenance measures for the fouled *** mechanisms for the different effects of coal fines and sand are also analyzed to understand the roles that various fouling material plays in the fouled ballast.

关键词： Railway ballast Fouled ballast Shear strength Direct shear test Contamination

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D2SFormer: Dual attention-dynamic bidirectional Transformer for semantic segmentation of urban remote sensing images

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IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2025年 18卷 12248-12262页

作者： Yan, Yi Li, Jiafeng Zhang, Jing Wang, Liuqian Zhuo, Li Beijing University of Technology School of Information Science and Technology Chaoyang Beijing100124 China Beijing University of Technology Beijing Key Laboratory of Computational Intelligence and Intelligent System China

Semantic segmentation of urban remote sensing images (URSIs) is crucial for the development of smart cities and the acceleration of urban information. In view of the characteristics of URSIs with intricate backgrounds, dense distributions of feature objects, and varying object scales, we propose a dual attention-dynamic bidirectional Transformer (D2SFormer) for semantic segmentation of URSIs. First, a dual attention Transformer encoder has a global branch of cross-shaped window self-attention (CWSA) and a local branch of convolutional channel attention block (CCAB), which helps to enhance pixel-level semantic discrimination. Then, CCAB combines the local sensitivity of Conv with the non-local modeling capability of ECA for overlapping region resolution. Finally, the decoder dynamically fuses multiscale features to reconstruct boundaries and suppress artifacts by using a bidirectional feature pyramid network (BiFPN) and dysampling. Experimental results demonstrate that our D2SFormer achieves mIoUs of 87.84%, 81.24%, and 53.19% on the Potsdam, Vaihingen, and LoveDA datasets, respectively, which is highly competitive with existing methods. © 2008-2012 IEEE.

关键词： Semantic Segmentation

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Decentralized Federated Learning Algorithm Under Adversary Eavesdropping

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IEEE/CAA Journal of Automatica Sinica 2025年第2期12卷 448-456页

作者： Lei Xu Danya Xu Xinlei Yi Chao Deng Tianyou Chai Tao Yang the State Key Laboratory of Synthetical Automation for Process Industries Northeastern University the Department of Mechanical Engineering University of Victoria Shanghai Institute of Intelligent Science and Technology Tongji University IEEE the Institute of Advanced Technology Nanjing University of Posts and Telecommunications

In this paper, we study the decentralized federated learning problem, which involves the collaborative training of a global model among multiple devices while ensuring data *** classical federated learning, the communication channel between the devices poses a potential risk of compromising private information. To reduce the risk of adversary eavesdropping in the communication channel, we propose TRADE(transmit difference weight) concept. This concept replaces the decentralized federated learning algorithm's transmitted weight parameters with differential weight parameters, enhancing the privacy data against eavesdropping. Subsequently, by integrating the TRADE concept with the primal-dual stochastic gradient descent(SGD)algorithm, we propose a decentralized TRADE primal-dual SGD algorithm. We demonstrate that our proposed algorithm's convergence properties are the same as those of the primal-dual SGD algorithm while providing enhanced privacy protection. We validate the algorithm's performance on fault diagnosis task using the Case Western Reserve University dataset, and image classification tasks using the CIFAR-10 and CIFAR-100 datasets,revealing model accuracy comparable to centralized federated learning. Additionally, the experiments confirm the algorithm's privacy protection capability.

关键词： Adversary eavesdropping decentralized federated learning privacy protection stochastic gradient descent

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Multi-objective concurrent isogeometric topology optimization of multiscale structures

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Frontiers of Mechanical Engineering 2025年第1期20卷 105-127页

作者： Jianli LIU Hongshuo FAN Tao NIE Haobo ZHANG Jingui YU Shuting WANG Zhaohui XIA State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Mechanical and Electronic Engineering Wuhan University of TechnologyWuhan 430070China

Multiscale structures require excellent multiphysical properties to withstand the loads in various complex engineering *** this study,a concurrent isogeometric topology optimization method is proposed to design multiscale structures with high thermal conductivity and low mechanical ***,the mathematical description model of multi-objective topology optimization for multiscale structures is constructed,and a single-objective concurrent isogeometric topology optimization formulation for mechanical and thermal compliance is ***,by combining the isogeometric analysis method,the material interpolation model and decoupled sensitivity analysis scheme of the objective function are established on macro and micro *** solid isotropic material with penalization method is employed to update iteratively the macro and microstructure topologies ***,the feasibility and advantages of the proposed approach are illustrated by several 2D and 3D numerical examples with different volume fractions,while the effects of volume fraction and different boundary conditions on the final configuration and multi-objective performance of the multiscale structure are *** show that the isogeometric concurrent design of multiscale structures through multi-objective optimization can produce better multi-objective performance compared with a single-scale one.

关键词： isogeometric topology optimization multiscale structure multi-objective optimization thermal conductivity mechanical compliance

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Differential Protection Method of Stator and Rotor Current with Different Frequencies for Variable Speed Pumped Storage Units

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IEEE Transactions on Power Delivery 2025年第3期40卷 1531-1539页

作者： Qiao, Jian Yu, Haoyuan Wang, Yikai Wang, Kai Yin, Xin Chen, Linxu State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources Baoding China Wuhan University of Technology School of Automation Wuhan China

Rotor winding short-circuit fault (RWSF) is a common fault type of variable speed pumped storage unit (VSPSU). However, the RWSF protection in engineering typically depends on the integrated over-current protection of the AC excitation system, which has poor sensitivity to reflect the RWSF and makes it difficult to fulfill the requirements of safe operation of VSPSU. Inspired by transformer differential protection, a different frequency differential protection method using both stator and rotor phase currents is proposed. In terms of working principle and structure, the stator and rotor windings of the VSPSU are similar to the primary and secondary windings of the transformer, and there are conditions for differential protection. Furthermore, the Clark transformation is used to analyze the characteristic changes of stator and rotor currents after the RWSF. On this basis, the criterion form of different frequency differential protection is constructed based on the trapezoidal area method. Finally, the effectiveness of the proposed method is verified by dynamic simulation experiments. © 1986-2012 IEEE.

关键词： Stators

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Effects of Dual Incorporation of Nano-SiO_(2)and Nano-CaCO_(3)on the Abrasion Resistance and Microstructure of Concrete

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Journal of Wuhan University of technology(Materials Science) 2025年第2期40卷 509-518页

作者： SU Jun YANG Haixin WANG Songbo TIAN Jing CAI Xinhua SHUI Farun HUANG Fu XU Ziyang ZENG Qingdian FAN Zikang School of Civil Engineering Architecture and EnvironmentHubei University of TechnologyWuhan 430068China Key Laboratory of Intelligent Health Perception and Ecological Restoration of Rivers and Lakes Ministry of EducationHubei University of TechnologyWuhan 430068China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China

Seven sets of concrete containing different mass ratios of nano-SiO_(2)(0%-5.0%)and nano-CaCO_(3)(0%-1.5%)were designed.A total of 28 concrete cube specimens cured for 7 and 28 days were tested for compressive strength(14 specimens)and split tensile strength(14 specimens),while 7 cylindrical specimens cured for 28 days were tested for impact *** impact resistance of the concrete specimens was quantitatively analyzed by using impact strength(f_(a))and wear rate(L_^(a)),and the effect of dual incorporation of nano-SiO_(2)and nano-CaCO_(3)on the microstructure of concrete was further investigated by XRD and *** experimental results indicate that the incorporation of 5.0%nano-SiO_(2)and 1.5%nano-CaCO_(3)improves the mechanical properties and impact resistance of concrete most significantly,and the compressive strength,split tensile strength,and impact resistance increase by around 37.80%,35.31%,and 183.36%,respectively,compared with that of ordinary *** the microscopic level,nano-SiO_(2)reacts with C-H in a secondary hydration reaction to increase the number of C-S-H gels,which improves the pore structure in the matrix and favorably enhances the adhesion between aggregate and cement paste in the weakened layer,thus improving the abrasion resistance of concrete.

关键词： nano-SiO_(2) nano-CaCO_(3) mechanical properties abrasion resistance microstructure of concrete

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A Method for Abnormality Detection of Lithium-Ion Battery Packs Based on Kullback-Leibler Test and Greenwald-Khanna Clustering 11th

A Method for Abnormality Detection of Lithium-Ion Battery Pa...

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11th Frontier Academic Forum of Electrical Engineering, FAFEE 2024

作者： Wang, Chong Liu, Yajie Song, Yuanming Wang, Yu College of System Engineering National University of Defense Technology Changsha410073 China Hunan Key Laboratory of Multi-Energy System Intelligent Interconnection Technology Changsha410073 China

ISBN: (纸本)9789819788231

During the operation of lithium-ion battery packs, there often exhibit certain abnormalities due to cell faults such as internal short circuit or unavoidable inconsistencies among cells, which affects the operation safety of the battery packs. Therefore, it is of great significance to carry out abnormality detection for the battery packs. Accordingly, this paper proposes a feature selection method based on Kullback-Leibler (K-L) test and an improved Greenwald-Khanna (GK) clustering algorithm. Initially, faults are introduced into the battery pack using the Simulink simulation platform to obtain simulation data. Subsequently, parameter identification is identified based on the Rint equivalent circuit model and the Recursive Least Squares (RLS) algorithm. Finally, better consistency features are selected using the K-L test as inputs to the GK clustering algorithm, and the K-Means++ method is used to optimize the GK algorithm for clustering features. The results demonstrate that this method can effectively distinguish between normal and abnormal batteries, achieving abnormality detection in battery packs. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Clustering algorithms

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Main Protection Optimization Scheme for Generator Parallel Operation of Rotating Asynchronous Machine in Nuclear Power Plants

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IEEE Transactions on Power Delivery 2025年第3期40卷 1480-1492页

作者： Wang, Yikai Xu, Chaozheng Qiao, Jian Dai, Zhihui Tan, Liming Yin, Xianggen State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources Baoding071003 China State Grid Hunan Electric Power Company Limited Research Institute Changsha410208 China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Technology Wuhan430074 China

The Rotating Asynchronous Machine (RAM) system of a nuclear power plant provides a stable and reliable power supply for the control rod drive mechanism (CRDM) through two parallel generators. At present, the main protection of the generators in the RAM system is only configured with longitudinal differential protection, which cannot reflect the interturn short circuit fault and interbranch short circuit fault of the stator winding. Based on the characteristics of parallel connection of RAM generators in nuclear power plants, this article proposes a dual-generator split phase transverse differential protection and a dual-generator incomplete longitudinal differential protection. Through the internal fault set of the generator and the internal fault potential splitting model of the generator, the quantitative analysis of different main protection configuration schemes is carried out. It is concluded that the existing longitudinal differential protection and the incomplete longitudinal differential protection of two parallel generators can correctly reflect the vast majority of internal short-circuit faults. Finally, the dynamic experiment is carried out to prove the feasibility of the protection method in the actual unit operation. © 1986-2012 IEEE.

关键词： Nuclear power plants

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A Novel Large-Scale 3D Printing Apparatus for Complex Geological Models and Its Application

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Rock Mechanics and Rock Engineering 2025年 1-22页

作者： Mei, Shi-Ming Li, Zheng-Wei He, Ben-Guo Song, Jia-Qi Zhang, Ming-Yu Zhang, Wei State Key Laboratory of Intelligent Deep Metal Mining and Equipment Northeastern University Shenyang 110819 China Key Laboratory of Liaoning Province on Deep Engineering and Intelligent Technology Northeastern University Shenyang 110819 China

This paper presents a novel large-scale 3D printing apparatus for fabricating complex geological models. The 3D printing apparatus is designed based on the wet-material extrusion deposition molding process, which comprises a mechanical frame, a feeding subsystem, a transportation device, and a control subsystem. During the development of this 3D printing apparatus, some key technical difficulties were solved. 3D printing materials with good physical and mechanical similarity to natural rocks were developed. Continuous printing of large-scale complex geological models was achieved using a gantry frame and a fixed printing platform. Automated transportation of the large volume and weight geological models from the 3D printing apparatus to the loading system was completed. To verify the effectiveness of this apparatus, a 2 m × 2 m × 1.5 m complex geological model with two faults was successfully printed. Based on this printed model, true triaxial geomechanical model tests were performed to simulate the step-by-step excavation process of a deep tunnel in southwestern China. The test captured the macroscopic failure process of the surrounding rock caused by high in situ stress, two faults, and excavation unloading. The model test results show good consistency with the failure characteristics of the surrounding rock in the field. This 3D printing apparatus offers a novel approach to preparing complex geological models. © The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature 2025.

关键词： 3D printing apparatus Complex geological structures Failure mechanism of deep tunnels Large-scale geological model True triaxial loading tests

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Adaptive multi-segment pseudospectral sequential convex programming for satellite cluster reconfiguration trajectory optimization

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Advances in Space Research 2025年第8期75卷 6317-6341页

作者： Wang, Lixiang Ye, Dong Kong, Xianren Xiao, Yan Research Center of Satellite Technology Harbin Institute of Technology Harbin150001 China State Key Laboratory of Micro-Spacecraft Rapid Design and Intelligent Cluster Harbin Institute of Technology Harbin150001 China

This paper presents an adaptive pseudospectral sequential convex programming method aimed at enhancing computational efficiency and safety in large-scale satellite cluster reconfiguration trajectory optimization. First, a multi-segment pseudospectral discretization technique is combined with successive linearization to transform the nonconvex optimal control problem into a series of convex subproblems. Second, an adaptive segmentation strategy based on collision warnings divides the entire orbital transfer process into collision-warning and non-collision-warning phases, with varying grid densities applied. This strategy improves satellite safety without increasing the total number of discretization points. Third, a filtering strategy is introduced to accurately identify the collision avoidance objects and periods, eliminating a large number of inactive collision avoidance constraints. This reduces the complexity of the convex subproblems and alleviates the computational burden. Finally, numerical simulation results demonstrate that the proposed method outperforms the traditional sequential convex programming and GPOPS methods in terms of efficiency, accuracy, and safety in scenarios involving 2 to 100 satellites. For the 8-satellite case, the proposed method improves computational efficiency by 99% over GPOPS and 65% over trapezoidal discretization sequential convex programming. © 2025 COSPAR

关键词： Orbital transfer

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