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2020 7th International Conference on Computer-Aided design, Manufacturing, Modeling and Simulation, CDMMS 2020

作者： Yao, Jinling Liu, Jie College of Electronic Information and Engineering Tianjin Vocational Institute Tianjin300000 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China Tianjin300384 China

This article introduces computer network intrusion detection systems and their classification based on artificial intelligence technology, and points out the challenges that intrusion detection systems (IDS) are facing in wireless sensor computer networks. On this basis, a hierarchical multi-layer wireless sensor network intrusion detection system and technology based on artificial intelligence technology Agent is proposed, and its network structure, working principle and performance are analysed. © Published under licence by IOP Publishing Ltd.

关键词： Intrusion detection

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Elucidating the Rate Limitation of Lithium-Ion Batteries Under Different Charging Conditions Through Polarization Analysis

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SSRN 2023年

作者： Xie, Wenlong Guo, Peng Gao, Xinlei Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China Dyson School of Design Engineering Imperial College London London United Kingdom

The charging performance of lithium-ion batteries is significantly affected by the polarization effect, which leads to increased resistance and prolonged charging time. this paper combines experimental testing with numerical simulation to qualitatively and quantitatively investigate the polarization effects under different charging conditions. The results indicate that the proportions of positive and negative polarization to cell polarization are comparable and basically constant with variations in the charging rate. The polarization voltages of different categories within the electrode are positively correlated with the charging rate. At high charging rates, electrochemical polarization accounts for the majority, followed by solid-phase and liquid-phase concentration polarization, while solid-phase and liquid-phase ohmic polarization is relatively negligible. On the other hand, the cell polarization exhibits a non-linear trend with temperature. The lower the temperature, the greater the proportion of negative polarization, while positive polarization is insensitive to temperature. At low temperature charging, the solid-phase concentration polarization of the negative electrode accounts for the majority of electrode polarization, which can be attributed to the larger lithium ion concentration gradient induced by the sluggish diffusion of ions in the active material. In-depth investigation of the polarization effect will provide guidance for achieving more efficient charging under different operating conditions. © 2023, The Authors. All rights reserved.

关键词： Lithium-ion batteries

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Structural Optimization of a Magnetically Operated Actuator Mechanism for 10kV Circuit Breaker

Structural Optimization of a Magnetically Operated Actuator ...

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system Simulation Technology and its Application (CCSSTA), IEEE China Conference on

作者： Chao Liang He Tian Guanqiao Zhao Jiangping Li Ziliang Zhu Ruixuan Shen 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 Tianjin Sanyuan Power Equipment Manufacturing Co. Ltd Tianjin China

ISBN: (数字)9798350366600

ISBN: (纸本)9798350366617

As the demand for reliable power supply in power systems grows, ensuring the performance of circuit breaker operating mechanisms is crucial. This performance is pivotal to the stability of the power grid, the speed of fault recovery, and the equipment’s lifespan. In this paper, we introduce a structural optimization plan for a new magnetic control operating mechanism designed for 10kV circuit breakers. Employing three-dimensional and mathematical modeling, complemented by finite element analysis with Maxwell software, we delved into an in-depth study of the mechanism’s structure, performance, and materials. We further conducted a parametric design and comparative analysis of key components. The simulation results, which exclude the spring load, demonstrate that the optimized circuit breaker can achieve a closing velocity of 3.07 m/s, an electromagnetic force peaking at 2.7 kN, and a closure time minimized to 8.5 ms. These enhancements notably improve the mechanism’s closing efficiency. Consequently, our research introduces a novel perspective to the field of reliability studies for magnetic control operating mechanisms.

关键词： Magnetic cores Circuit breakers Magnetic domains Power system stability Power system reliability Magnetic analysis Magnetosphere Integrated circuit reliability Magnetic circuits Optimization

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Exploration and Practice of Hierarchical Graduation Project under the Background of Science Collaborative Education and Engineering Education Accreditation 21

Exploration and Practice of Hierarchical Graduation Project ...

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Proceedings of the 5th International Conference on Advances in Artificial Intelligence

作者： Lilan Gao Yansong Tan Yanfang Sun Linwei Lv Bin Li Qijun Gao Xiaofei Wang Yijiao Zhao School of Mechanical Engineering_Tianjin Key Laboratory for Advanced Mechatronic System Design and intelligent Control_National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China School of Mechanical Engineering_Tianjin Key Laboratory for Advanced Mechatronic System Design and intelligent Control Tianjin University of Technology China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China

ISBN: (纸本)9781450390699

Graduation project is an important integrated practice segment for undergraduate education, since the quality of undergraduate education can be directly evaluated by the quality of graduation project. Under the background of science collaborative education and engineering education accreditation, it is necessary to explore an intelligent and integrated graduation project system to train students by all sorts of engineering and research projects, thus improve students' practical ability and innovation ability. This paper first analyzed the problems of the graduation project in the major of process equipment and control engineering, then introduced a novel hierarchical graduation project system to adapt to the concept of science collaborative education and engineering education. By putting the novel graduation project system into effect, the quality of graduation project has significantly improved.

关键词： Science collaborative education Hierarchical graduation project Engineering education accreditation Education reform

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Location IoU: A New Evaluation and Loss for Bounding Box Regression in Object Detection

Location IoU: A New Evaluation and Loss for Bounding Box Reg...

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International Joint Conference on Neural Networks (IJCNN)

作者： Lu Yang Kai Zhang Jiaqi Liu Chongke Bi Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China Autobrain (Tianjin) Technology LTD Tianjin China College of Intelligence and Computing Tianjin University Tianjin China

ISBN: (数字)9798350359312

ISBN: (纸本)9798350359329

In the field of object detection bounding box regression, IoU (Intersection over Union) is a commonly used evaluation metric for measuring the overlap between predicted and ground truth bounding boxes. One limitation of IoU, however, is that the gradient goes to zero when there is no intersection between bounding boxes. Recent evaluation metrics have been developed to overcome this problem by incorporating penalty terms and other techniques for improving IoU. Despite these advances, existing methods still suffer to some degree from the problems of small gradients and slow rate of convergence. In this paper, a new evaluation method named LIoU (Location IoU) is proposed to address these issues. It can maximize the shared area of the intersection when used as the loss function and incorporate a variable gradient parameter to fit to datasets of different sizes. The experimental results indicate that we achieve 0.27% and 3.48% accuracy improvements respectively in SSD and YOLOv5 network on the VOC dataset, and 2.23% in the YOLOv5 network on the COCO dataset. The results of this study highlight the effectiveness of LIoU in improving the performance of object detection models.

关键词： YOLO Measurement Location awareness Accuracy Shape Neural networks Benchmark testing

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Adversarial Learning Network for Recovering Rppg Signals from Low-Resolution Images for Remote Heart Rate Measurement

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SSRN 2024年

作者： Zhai, Dezhao Chen, Wei Li, Qinwei Yu, Ming Wu, Hang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China Systems Engineering Institute Academy of Military Sciences People's Liberation Army Tianjin300161 China Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin300300 China School of Artificial Intelligence Nankai University Tianjin300381 China

Remote Photoplethysmography (rPPG) is a non-contact method for measuring heart rate (HR) through facial video, which has significant research value and application potential. However, in long-distance vital sign measurement tasks, the low resolution of facial images and insufficient pixels in the facial region severely degrade the quality of the rPPG signals, leading to a sharp decline in HR accuracy. To address this issue, this paper proposes an adversarial learning network for recovering rPPG signals from low-resolution images (ALRSL-HR). First, arbitrary resolution face images are fed into multi-channel network to extract rPPG signal features capturing rich rPPG information, generating rPPG feature blocks, and temporally aggregating for richer feature representation. These features are then inputted into the backbone network to generate adversarial examples of rPPG signals of varying qualities. Finally, a two-stage adversarial loss function is employed to enable the low-quality rPPG signals to learn the periodic characteristics of high-quality rPPG signals, recover the low-quality signals, and narrow the quality gap between rPPG signals from low-resolution images. Extensive experiments were conducted in this paper to validate the effectiveness of our model on the public COHFACE, UBFC-Phys and UBFC-rPPG datasets. The results of the experiments demonstrate that the proposed ALRSL-HR model can effectively recover degraded rPPG signals from low-resolution images. © 2024, The Authors. All rights reserved.

关键词： Photoplethysmography

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An Improved Task Planning Method for Unmanned Swarms with Coupled Physical and Logical Constraints

An Improved Task Planning Method for Unmanned Swarms with Co...

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IEEE International Conference on Unmanned systems (ICUS)

作者： Xiubin Chen Lei Zhang Fang Xu Weiran Yao School of Astronautics Harbin Institude of Technology Harbin China Wuhan 2nd Ship Design and Research Institute Wuhan China Marine Military Intelligence Innovation Institute CSSC Systems Engineering Research Institute Beijing China National Key Laboratory of Complex System Control and Intelligent Agent Cooperation Beijing China

ISBN: (数字)9798350384185

ISBN: (纸本)9798350384192

Traditional task allocation methods for unmanned swarm systems ignore the effects of actual paths, resulting in estimation accuracy reduction. This paper formulates task planning problem by incorporating physical and logical constraints, and establishes an integrated framework of task allocation and path planning. Conflict-based search method is used to address path planning with physical constraints. A genetic algorithm is employed to solve multi-traveling salesman allocation problem. A bounded suboptimal optimization, a data dictionary, and an island model are introduced to accelerate the convergence speed of the genetic algorithm. The experiments verify that compared to the decoupled task planning methods, the proposed method improves task execution efficiency and remains adaptability to various complex spatial maps.

关键词： Dictionaries Search methods Estimation Path planning Data models Planning Resource management Optimization Genetic algorithms Convergence

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Newly Developed Universal Analytical Approach to Incomplete Spherical Conformal Contact Problems: Application to Spherical Plain Bearings with Self-Lubricating Fabric Liner

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SSRN 2024年

作者： Xue, Yahong Kang, Dongzhuang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China College of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

To address the conformal contact problem in self-lubricating spherical plain bearings bonded with a self-lubricating layer, a universal analytical model for normal contact between friction-less spheres is established. The accuracy and generality of this new model are verified through numerous finite element analyses. Our model overcomes the limitations of elastic half-space and small deformation assumptions. It can accurately calculate the contact stress distribution of self-lubricating spherical bearings bonded with a self-lubricating layer. Based on the new model, the complex non-linear relationship between the variables is being investigated. The model can be extended and applied to the conformal contact problem of spherical contact surfaces in biomechanics and other fields. © 2024, The Authors. All rights reserved.

关键词： Analytical models

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Study on the amplitude-frequency characteristics of a non-planar complex structure

Study on the amplitude-frequency characteristics of a non-pl...

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第八届国际振动工程会议

作者： Ruiqin Wu Wei Zhu Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System School of Mechanical EngineeringTianjin University of Technology

The amplitude-frequency characteristics of a non-planar complex structure composed of a flexible beam and a ring are systematically investigated. The kinetic and strain potential energy expressions are theoretically calculated for the beam-ring system. Hamilton's principle is employed to derive the nonlinear governing equations of motion of the beam-ring structure. The nonlinear partial governing differential equation of motion for the beam-ring system is discretized into two coupled ordinary differential equations including quadratic and cubic nonlinearities by using Galerkin's technique. The method of multiple scales is utilized to approximately analyze the dynamical system and yield a set of autonomous equations. The amplitude-frequency characteristics and the stability of the steady-state solution are studied numerically. The frequency-response curves show that there exist multi-value solution and jump phenomenon in the system and some parameters of the amplitude-frequency equations have significant contributions to the nonlinear responses of the beam-ring system.

关键词： the beam-ring structure amplitude-frequency characteristics steady-state solution jump phenomenon

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Simulation of crystal plasticity of P92 heat resistant steel considering martensitic lath structure

Simulation of crystal plasticity of P92 heat resistant steel...

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2021 International Conference on Materials Genetic Engineering and Information Science, MGEIS 2021

作者： Wang, Xinyu Shen, Junjie Guo, Xiangru Qiao, Jixin Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China

Based on the theory of crystal plasticity, coupled with dislocation and lath hardening models, this paper establishes a crystal plasticity finite element model describing the high temperature creep of P92 steel. Open source software was used to generate lath models with an average size of 350nm, 650nm and 950nm to explore the effect of lath coarsening on the high-temperature creep behavior of P92 steel. The results show that the roughening of the slats increases the rate of creep deformation, resulting in a decrease in the service life of the material. Observing the slat model, it can be seen that the roughening of the slats enlarges the numerical gradient of stress and strain, and aggravates the overall plastic strain of the model. The coarsening of the slats accelerates the movement of dislocations, causing the density of movable dislocations to increase, and at the same time the shear strain amplitude of the slip system increases, thereby reducing the hardening behavior of the material. © Journal of Physics: Conference Series 2021.

关键词： Coarsening

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