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2023 IEEE Far East NDT New Technology and Application Forum, FENDT 2023

作者： Niu, Xiao-Chuan Yang, Wen-Lin Zhu, Li-Qiang Shi, Hong-Mei Zhu, Xing-Hong Beijing Jiaotong University School of Mechanical Electronic and Control Engineering Beijing100044 China Frontiers Science Center for Smart High-speed Railway System Beijing100044 China Beijing Jiaotong University Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control Technology Ministry of Education Beijing100044 China China Railway Lanzhou Group Co. Ltd. Lanzhou730000 China

ISBN: (纸本)9798350303544

Nonlinear ultrasonic guided waves technology has shown excellent application potential in the field of structural stress testing due to its unique nonlinear characteristics and long distance detection range. However, the diversity and complexity of effects about stress on different cumulative second harmonics constrain the development of related research. In this paper, a numerical study about the response Law of different cumulative second harmonics with stress is undertaken based on ABAQUS software. A plate finite element model is established and the corresponding simulation experiment is carried out. The simulation result demonstrates that the variation tendencies of different cumulative second harmonic modes with stress are different, and their relative nonlinear parameters are monotonically increasing or decreasing with the increase of tensile stress. Therefore, in the application of stress detection, it is essential to analyze the response law of the selected cumulative second harmonic mode with stress change in advance. The simulation method proposed in this paper is also applicable to other studies about nonlinear ultrasonic waves and has wide applicability. © 2023 IEEE.

关键词： Ultrasonic waves

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Virtually coupled train set control subject to space-time separation:A distributed economic MPC approach with emergency braking configuration

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High-Speed Railway 2024年第3期2卷 143-152页

作者： Xiaolin Luo Tao Tang Le Wang Hongjie Liu State Key Laboratory of Advanced Rail Autonomous Operation Beijing Jiaotong UniversityBeijing 100044China Department of Electrical and Computer Engineering University of CaliforniaRiversideCA 92521USA Beijing Zongheng Electro-Mechanical Technology Development Co. Ltd.Beijing 100081China School of Automation and Intelligence Beijing Jiaotong UniversityBeijing 100044China National Engineering Research Center of Rail Transportation Operation and Control System Beijing Jiaotong UniversityBeijing 100044China

The emerging virtual coupling technology aims to operate multiple train units in a Virtually Coupled Train Set(VCTS)at a minimal but safe *** guarantee collision avoidance,the safety distance should be calculated using the state-of-the-art space-time separation principle that separates the Emergency Braking(EB)trajectories of two successive units during the whole EB *** this case,the minimal safety distance is usually numerically calculated without an analytic ***,the constrained VCTS control problem is hard to address with space-time separation,which is still a gap in the existing *** solve this problem,we propose a Distributed Economic Model Predictive control(DEMPC)approach with computation efficiency and theoretical ***,to alleviate the computation burden,we transform implicit safety constraints into explicitly linear ones,such that the optimal control problem in DEMPC is a quadratic programming problem that can be solved *** theoretical analysis,sufficient conditions are derived to guarantee the recursive feasibility and stability of DEMPC,employing compatibility constraints,tube techniques and terminal ingredient ***,we extend our approach with globally optimal and distributed online EB configuration methods to shorten the minimal distance among ***,experimental results demonstrate the performance and advantages of the proposed approaches.

关键词： Virtually coupled train set Space-time separation Economic model predictive control Distributed model predictive control Emergency braking configuration

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Design and Practice of Blended Teaching Model of engineering Professional courses based on Outcome-based Education

Design and Practice of Blended Teaching Model of Engineering...

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Educational Technology (ICET), IEEE International Conference on

作者： Jinyou Xu Lei Zhang Chengjie Rui Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) Tianjin China

In the context of engineering education, to improve the practical engineering skills of engineering students, the teaching ideas and implementation methods of the curriculum are designed based on Outcome-based Education. A blended teaching approach was used to design the implementation process to achieve the curriculum objectives. In this paper, we explain the process of blended teaching from the two aspects of basic knowledge and competency training. Active learning of basic knowledge is implemented based on a three-step blended teaching model before, after, and during classes. It adopts the project-driven learning approach of the flipped classroom model and cultivates students' ability to solve complex engineering problems through collaborative group and intra-group mutual assessment. Based on the original objective assessment of the curriculum and under the current teaching model, we design a diversified evaluation approach to comprehensively assess the effectiveness of student competence achievement. Practice has shown that project-based inquiry-based teaching methods based on the flipped classroom model can promote learning outcomes for students and increase their interest in learning. It avoids the blind and aimless theoretical learning process of the student and improves the practical ability of the student. The methods and means of instruction of teachers have been further extended, and the ability of students to learn independently has been improved.

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A Novel Frequency Estimation Strategy and Filter Based on the Gearbox Response Mechanism Model

SSRN

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SSRN 2024年

作者： Li, Decai Chen, Jiwei Xie, Ruitong Luo, Zhiweng Sheng, Yanliang Hu, Mantang Wang, Guofeng Zhang, Mian Key Laboratory of Mechanism Theory and Equipment Design Ministry of Education School of Mechanical Engineering Tianjin University Tianjin300072 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

In the gearbox response signal, numerous sideband components generated by different fault characteristic frequencies are interleaved. Coupled with the noise interference, this makes health monitoring based on spectral analysis highly challenging. Traditional filtering methods, such as low-pass, high-pass and band-pass filters, and mode decomposition methods, exhibit limitations in filtering out interference signals over the entire frequency spectrum. Moreover, the absence of speed information complicates the determination of appropriate passbands. Most critically, noise within the passband is entirely retained. To address these issues, this paper proposes a methodology for estimating characteristic frequencies and filtering interference signals based on a novel response mechanism model (RMM) of gearbox. The proposed RMM model takes into account the structural attributes and vibration response mechanism of the gearbox, describing the modulation phenomena of fault characteristic frequencies on the meshing frequency and its harmonics. The proposed model-based frequency estimation (MFE) strategy accurately computes characteristic frequencies even in the absence of speed information. Additionally, the proposed model-based filter (MF) can perform accurate filtering over the entire frequency spectrum or within specified gear train vibration responses. Numerical simulations and experimental data validate the viability and effectiveness of the proposed methods. © 2024, The Authors. All rights reserved.

关键词： Frequency estimation

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Construction and Application of the Teaching Cloud Platform for engineering Drawing course

Construction and Application of the Teaching Cloud Platform ...

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International Conference on Educational and Information Technology (ICEIT)

作者： Yahong Xue Haozhi Mu Lijun Xue Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China

A cloud platform for engineering drawing course teaching was proposed based on cloud station. The cloud station can solve the common problems existed in engineering drawing course, such as the difficulty of teaching, the heavy work of tutorship, the poor teaching effect, the weak spatial imagination of students, as well as the current difficulty to develop the virtual model resource base and the interaction is not strong. The platform uses Solidworks software to build 3D model library, and combines with CADbro's powerful cloud service and 3D file viewing function to realize the interaction and sharing with cloud model by using web browser. At the same time, we choose bilibili, a popular cultural site for teenagers, to release the explanation videos of exercises, and make use of the convenient way to build the cloud station to integrate, release and manage the resources. The platform realizes self-study and self-test at anytime and anywhere on both PC and mobile devices, and fast jumps the corresponding explanation video and cloud virtual model according to the demand. The virtual model in the cloud can be rotated, cut, distance measured, exploded, parts hidden, moved, 2D viewed and so on by touch. The platform is innovative, extensible, interesting and practical, which can greatly enhance the students' enthusiasm for independent learning, and it can be used reference to the development of engineering drawing teaching resources.

关键词： Cloud computing Solid modeling Three-dimensional displays engineering drawings Education Buildings Software

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Teaching Innovation and Practice of Mind Mapping Applied to engineering Drawing course

Teaching Innovation and Practice of Mind Mapping Applied to ...

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International Conference on Educational and Information Technology (ICEIT)

作者： Yahong Xue Haozhi Mu Lijun Xue Xiaofei Wang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China

engineering drawing is a compulsory technical foundation course for mechanical majors. Its main task is to cultivate students' ability to draw and read engineering drawings. The content of this course is complicated and abstract and not easy to understand, which makes it difficult for students to learn. Mind mapping is a visual thinking tool to systematize and organize abstract and complicated knowledge. Taking the application of mind mapping to various teaching processes of engineering drawing course, such as the construction of framework, the sorting out of fragmented knowledge, the solution of drawing geometry and sectional view, and the group project for important and difficult content as examples, we illustrate the importance of mind map in cultivating students' knowledge generalization ability, independent learning ability, enhancing students' logical thinking, creative thinking, divergent thinking, and stimulating students' interest in learning.

关键词： Knowledge engineering Geometry Visualization Technological innovation engineering drawings Education Task analysis

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Logistics Demand Forecasting and Scheduling Optimization Using K-Means Clustering and Deep Q-Network

Logistics Demand Forecasting and Scheduling Optimization Usi...

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Electronics, Energy systems and Power engineering (EESPE), IEEE International Conference on

作者： Kun Liang Hang Zhang School of Management Tianjin University of Technology Tianjin China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China

ISBN: (数字)9798350389579

ISBN: (纸本)9798350389586

With the rapid development of e-commerce and supply chain management, logistics demand forecasting and scheduling optimization have become key links in improving logistics efficiency and service quality. To meet this challenge, this paper proposes a logistics demand forecasting and scheduling optimization method that combines K-Means clustering with deep Q network (DQN). Cluster analysis is used to reduce data complexity, and deep reinforcement learning is used to achieve intelligent scheduling. First, the background, challenges and research motivation of logistics demand forecasting and scheduling optimization are introduced. Secondly, the research results in related fields are reviewed, and the shortcomings of current research are pointed out. Then, the K-Means clustering algorithm, deep $\mathbf{Q}$ network theory and specific models of logistics demand prediction and scheduling optimization are elaborated. Then, the performance of the proposed method is designed and tested. The experimental results show that the proposed method can significantly improve the accuracy of logistics demand prediction, up to 0.93, optimize scheduling strategies, reduce logistics costs, and improve customer satisfaction.

关键词： Training Accuracy Costs Computational modeling Customer satisfaction Demand forecasting Clustering algorithms Predictive models Scheduling Logistics

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UWB Non-Line-of-Sight Recognition and Suppression Methodology

UWB Non-Line-of-Sight Recognition and Suppression Methodolog...

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International Conference on Communication Software and Networks, ICCSN

作者： Zhengshuai Ni Haibo Zhou Guozheng Zhang Wangbei Xu National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University Tianjin China

Ultra-Wide Band (UWB) positioning system has become the main research object in indoor positioning field due to its superior positioning performance. Accuracy at the scale of centimeters is achievable in an ideal positioning scenario. Nonetheless, the intricate and changeable indoor surroundings may cause UWB signals to propagate beyond the line-of-sight (LOS) and weaken in signal strength, resulting in a considerable reduction in the precision of positioning. In this paper, methods for identifying non-line-of-sight (NLOS) errors, alleviating NLOS errors, and integrating multi-sensor information are analyzed and studied to provide reference for improving the NLOS positioning accuracy of UWB.

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Pressure-assisted Silver Sintering Structure Optimization for Power Modules 5

Pressure-assisted Silver Sintering Structure Optimization fo...

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5th International Conference on Optoelectronic Science and Materials, ICOSM 2023

作者： Zhang, Hao Xing, Yulong Gao, Lilan Liu, Zheng Tan, Yansong Lu, Guoquan Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin300384 China National Demonstration Center or Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China Tianjin Yixunyuan New Material Technology Co. Ltd. Tianjin300380 China School of Chemical Engineering Tianjin University Tianjin300350 China School of Materials Science and Engineering Virginia Polytechnic Institute and State University BlacksburgVA24061 United States

ISBN: (纸本)9781510674547

As mobile technology evolves from 5G to 6G, the demand for third-generation semiconductors such as SiC with higher power and frequency capabilities is increasing. Silicon Carbide power modules generate significant heat during operation, requiring large-area nano-silver sintering technology to improve module performance and reliability. However, in large-area sintering processes, low exhaust efficiency of solder paste by-products and uneven sintering pressure of the nano-silver paste result in poor sintering quality of the silver layer. This study aims to improve the sintering quality of interconnected silver layers by optimizing the sintering pressure distribution and adding rubber spacers to the sintering structure. ABAQUS was used to quantitatively analyze the effects of pressure methods and gasket material, diameter, and thickness on the stress distribution in the silver layer. Finally, based on the simulation results, an optimized sintering structure was proposed to unify the pressure and reduce the stress concentration in the silver layer, and verified experimentally by sintering tests. Compared with the traditional sintering structure, the application of a 2 mm thick fluoro rubber gasket with the same surface area as the silver layer in the optimized structure reduced the porosity to 2.15% and achieved a more dense sintered silver layer. © 2024 SPIE.

关键词： Finite element method

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Point-Plane Better than Point-Point – for Embedding-based USAD 8

Point-Plane Better than Point-Point – for Embedding-based U...

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8th International Conference on Video and Image Processing, ICVIP 2024

作者： Zhao, Zhirong Zhang, Yuanhao Yu, Zujun Zhu, Liqiang Science and-Technology Department Guoneng Shuohuang Railway Development Co Ltd. Cangzhou Cangzhou062350 China Frontiers Science Center for Smart High-Speed Rail System Beijing Jiaotong University Beijing100044 China State Key Laboratory of Advanced Rail Autonomous Operation Beijing Jiaotong University Beijing100044 China School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing100044 China

ISBN: (数字)9781510689244

ISBN: (纸本)9781510689237

As deep neural networks (DNNs) have advanced, high-quality pre-trained models have provided excellent feature extraction methods for embedding-based unsupervised anomaly detection (EUSAD). However, when calculating anomaly scores, common EUSAD models often rely on point-to-point distance computations between test features and reference features. This approach not only fails to fully utilize the carefully integrated reference feature library but may also increase pixel-level false positives due to the incorrect selection of reference points. To address this issue, this paper adopts the least squares method, evaluating anomalies by calculating the distance between test feature points and the reference feature plane. Experimental results demonstrate that this method not only performs well in global image detection but also significantly reduces pixel-level false positives, showing strong performance across many anomaly detection datasets. © 2025 SPIE.

关键词： Pixels

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