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Fabrication of wear-resistant PA6 composites with superior thermal conductivity and mechanical properties via constructing highly oriented hybrid network of SiC-packed BN platelets

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Journal of Materials Science & Technology 2023年第15期146卷 200-210页

作者： Jing Chen Jiaming Zhu Yang Pan Hong Wu Shaoyun Guo Jianhui Qiu The State Key Laboratory of Polymer Materials Engineering Sichuan Provincial Engineering Laboratory of PlasticRubber Complex Processing TechnologyPolymer Research Institute of Sichuan UniversityChengdu 610065China Jiangsu Industrial Technology Research Institute of Advanced Polymer Materials Nanjing 211899China Department of Mechanical Engineering Faculty of Systems Science and TechnologyAkita Prefectural UniversityAkita 015-0055Japan

Herein,a strong extensional and shearing field was introduced to construct highly oriented hybrid networks of silicon carbide(SiC)-packed boron nitride(BN)platelets to fabricate high-performance wearresistant PA6 *** show that in-plane and through-plane thermal conductivity(TC)of the prepared PA6 composites with a total filler loading of 20 wt.%reached 1.31 and 0.35 W/(m K),352%and 25%higher than those of pure PA6,*** is attributed to the highly oriented hybrid network that facilitates the formation of efficient thermal conductivity *** monitoring results during friction confirm that high TC favors the friction heat dissipation ***,the yield strength of PA6 composites increased by 39.1%and they still have excellent ductility with an elongation at break of 207.1%.Finally,the wear rate of PA6 composites decreased sharply by 92.5%.This method can be used to manufacture advanced linear bearing and guideway parts,etc。

关键词： Polymer-matrix composites(PMCs) Hybrid Wear Thermal properties

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ProCQA: A Large-scale Community-based Programming Question Answering Dataset for Code Search 30

ProCQA: A Large-scale Community-based Programming Question A...

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Joint 30th International Conference on Computational Linguistics and 14th International Conference on Language Resources and Evaluation, LREC-COLING 2024

作者： Li, Zehan Zhang, Jianfei Yin, Chuantao Ouyang, Yuanxin Rong, Wenge State Key Laboratory of Complex & Critical Software Environment Beihang University China Sino-French Engineer School Beihang University China School of Computer Science and Engineering Beihang University China

ISBN: (纸本)9782493814104

Retrieval-based code question answering seeks to match user queries in natural language to relevant code snippets. Previous approaches typically rely on pretraining models using crafted bi-modal and uni-modal datasets to align text and code representations. In this paper, we introduce ProCQA, a large-scale programming question answering dataset extracted from the StackOverflow community, offering naturally structured mixed-modal QA pairs. To validate its effectiveness, we propose a modality-agnostic contrastive pre-training approach to improve the alignment of text and code representations of current code language models. Compared to previous models that primarily employ bimodal and unimodal pairs extracted from CodeSearchNet for pre-training, our model exhibits significant performance improvements across a wide range of code retrieval benchmarks. © 2024 ELRA Language Resource Association: CC BY-NC 4.0.

关键词： Benchmarking

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Vision DualGNN: Semantic Graph Is Not Only You Need 27th

Vision DualGNN: Semantic Graph Is Not Only You Need

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27th International Conference on Pattern Recognition, ICPR 2024

作者： Zheng, Xiaolong Wang, Jianming Xiao, Zhitao Sun, Yukuan School of Software Tiangong University Tianjin China Tianjin Key Laboratory of Autonomous Intelligence Technology and Systems Tiangong University Tianjin China Tianjin Key Laboratory of Optoelectronic Detection Technology and Systems Tiangong University Tianjin China Center for Engineering Intership and Training Tiangong University Tianjin China

ISBN: (纸本)9783031781063

Graph Neural Networks (GNNs) have shown great potential in visual tasks, yet they face challenges in effectively constructing and processing graphs. Vision GNN (ViG) was developed to tackle these issues by segmenting images into patches treated as nodes, with edges formed by connecting the nearest semantic neighbors. However, relying solely on semantic information for graph construction confines itself to a dispersed distribution of object neighbors, leading to inadequate graph processing. To address this issue, we propose Vision DualGNN(VDG), a novel dual graph neural network architecture that leverages both spatial and semantic information to construct and process graph representation of images. We apply a node encoder that transforms image patches into expressive node features. Additionally, we implement a dual-stream GNN that operates on both a spatial graph and a semantic graph. The spatial graph serves as a constraint for the semantic graph, enhancing the node features with spatial awareness. To verify the validity of our architecture, we have conducted our experiments on the ImageNet and CIFAR-100 datasets. And achieved state-of-the-art performance compared to other baseline models. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： dualgnn graph convolution semantic graph spatial graph

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YFLM: An Improved Levenberg-Marquardt Algorithm for Global Bundle Adjustment 41st

YFLM: An Improved Levenberg-Marquardt Algorithm for Global ...

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41st Computer Graphics International Conference, CGI 2024

作者： Peng, Jiaxin Li, Tao Jiang, Qin Liu, Jie Wang, Ruibo Laboratory of Software Engineering for Complex Systems School of Computer Science National University of Defense Technology Hunan Changsha410073 China Parallel and Distributed Processing Laboratory School of Computer Science National University of Defense Technology Hunan Changsha410073 China

ISBN: (纸本)9783031820205

The conventional Levenberg-Marquardt (LM) algorithm is a state-of-the-art trust-region optimization method for solving bundle adjustment problems in the Structure-from-Motion community, which not only takes advantage of the fast convergence of the Gauss-Newton method, but also the stability of the gradient descent method when approaching optimal solutions. However, the damping ratio of LM is simply provided by trial-and-error, which causes slow convergence rate for large-scale problems. This paper proposes the Yamashita-Fukushima LM (YFLM) algorithm to reduce the time complexity for global bundle adjustment, where the damping factor is determined by Yamashita and Fukushima’s method. YFLM dynamically calculates a more reasonable and optimal damping ratio according to the newest reprojection error. The experimental results show that the YFLM algorithm outperforms the conventional LM algorithm for most public bundle adjustment datasets. Besides this, the convergence of the YFLM algorithm is also evaluated with different σ∈(0,2]. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Damping

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Analytic derivation of Monin-Obukhov similarity function for open atmospheric surface layer

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Science China(Physics,Mechanics & Astronomy) 2021年第3期64卷 73-83页

作者： Yong Ji Zhen-Su She State Key Laboratory for Turbulence and Complex Systems and Department of Mechanics and Engineering Science College of EngineeringPeking UniversityBeijing100871China

The Monin-Obukhov(MO)similarity functionφm of the atmospheric surface layer(ASL)describing the deviation from the log law of the canonical turbulent boundary layer because of thermal stratification has been traditionally determined *** study presents a unified analytic expression derived from a symmetry-based theory of wall turbulence,called structural ensemble dynamics(SED),which postulates a generalized dilation symmetry principle expressing the effect of the wall on turbulence,leading to an analytic multi-regimes expression for the mixing *** ASL in unstable and stable conditions(i.e.,UC and SC),a unified two-regime formula of the mixing length is proposed,leading to aφm,similar to the Businger-Dyer(BD)formula;with a simplified model energy balance equation,φm is completely specified with no free ***,the theory allows the study of the open ASL’s underlying additional physical processes such as bottom-up or top-down flux due to pressure variations *** that Tp is decomposed into shear-like and buoyancy-like components,we propose new explanations for two important features of typical ASL:a significantly smaller Karman constant of 0.36 and a varyingφm for SC mean speed *** theory is validated by the data obtained at Kansas and also at Qingtu Lake Observation Array in Northern China for a variety of heat flux *** conclusion,due to pressure variations,we assert that ASL is intrinsically open and that the current theory offers a new basis for its quantification.

关键词： Monin-Obukhov similarity theory open atmospheric surface layer boundary layer turbulence symmetry-based analysis

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Multiple AMR Rigid Formation Control With Collision Avoidance Based On MADDPG 41

Multiple AMR Rigid Formation Control With Collision Avoidanc...

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第41届中国控制会议

作者： Kaiqi Wu Qing Wang YongBao Wu Jian Liu Lei Xue The College of Software Engineering Southeast University SEU-Monash Joint Graduate school Southeast University School of Automation Southeast UniversityKey Laboratory of Measurement and Control of Complex Systems of EngineeringMinistry of Education

ISBN: (数字)9789887581536

ISBN: (纸本)9781665482561

Recently,the formation control of multiple autonomous mobile robots(AMRs) have gained significant attention,and autonomous mobile robots(AMRs) have applied to all aspects of our ***-agent reinforcement learning is used to solve the autonomously sequential decision-making problem of agents in a common environment with competition or ***,we present a utility function and a reward function to achieve formation control with collision avoidance for a rigid AMRs system,and build a simulation environment to meet environmental requirements based on MPE.

关键词： Formation control Reinforcement learning Rigid system Collision avoidance

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DMGA: A Directional-Mutation Genetic Algorithm for CDMS Problem of Kafka 21

DMGA: A Directional-Mutation Genetic Algorithm for CDMS Prob...

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21st International Conference on Networking, Sensing and Control, ICNSC 2024

作者： Ma, Hanbo Ma, Yaofei Yuan, Haitao Wang, Meijia Hu, Jingwei Wang, Yihuan Yang, Hanbo School of Automation Science and Electrical Engineering Beihang University Beijing100191 China Beijing Simulation Center National Key Laboratory of Modeling and Simulation for Complex Systems Beijing China

ISBN: (纸本)9798350365221

With the increasing role of distributed message systems (DMS) represented by Kafka in handling large-scale data streams, it is critical to improve system performance by optimizing configuration parameters in different production environments. Due to the target system possessing numerous configuration parameters and the complex interactions between them, parameter optimization becomes a complex and time-consuming process that relies heavily on human effort and an iterative trial-and-error approach. At present, this type of configuration parameter problem has been classified as the Configuration of Distributed Message systems (CDMS) problem, for which the goal is to obtain the optimal set of parameters for achieving the best performance. In order to deal with this complex problem, an automatic optimization method is proposed in this paper, which combines an automatic script-based deployment and running framework with an improved Genetic Algorithm (GA) in cooperation with the Random Forest (RF) and statistical methods, named the Directional-Mutation Genetic Algorithm (DMGA). The framework and algorithm are designed to find the best configuration efficiently, obtaining optimal parameters accurately without human supervision. Actual results of comparison experiments based on the Kafka system show that the DMGA algorithm significantly improves the data throughput performance of Kafka, and its optimization speed is more efficient than the basic GA, highlighting its potential to quickly optimize Kafka's operational efficiency in different scenarios. © 2024 IEEE.

关键词： Genetic algorithms

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Instability-Induced Origami Design by Topology Optimization

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Acta Mechanica Solida Sinica 2023年第4期36卷 506-513页

作者： Weiwei Wang Ke Liu Meiqi Wu Hongyuan Li Pengyu Lv Huiling Duan State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering ScienceBIC-ESATCollege of EngineeringPeking UniversityBeijing 100871China Department of Advanced Manufacturing and Robotics College of EngineeringPeking UniversityBeijing 100871China CAPT HEDPS and IFSACollaborative Innovation Center of MoEPeking UniversityBeijing 100871China

Instability-induced wrinkle patterns of thin sheets are ubiquitous in nature,which often result in origami-like patterns that provide inspiration for the engineering of origami *** by instability-induced origami patterns,we propose a computational origami design method based on the nonlinear analysis of loaded thin sheets and topology *** bar-and-hinge model is employed for the nonlinear structural analysis,added with a displacement perturbation strategy to initiate out-of-plane *** ideas from topology optimization,a continuous crease indicator is introduced as the design variable to indicate the state of a crease,which is penalized by power functions to establish the mapping relationships between the crease indicator and hinge *** the structural strain energy with a crease length constraint,we are able to evolve a thin sheet into an origami structure with an optimized crease *** examples with different initial setups are illustrated,demonstrating the effectiveness and feasibility of the method.

关键词： Origami structure Instability Topology optimization Bar-and-hinge model

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Apollonius Partitions Based Pursuit-evasion Game Strategies by Q-Learning Approach 41

Apollonius Partitions Based Pursuit-evasion Game Strategies ...

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第41届中国控制会议

作者： Qing Wang KaiQi Wu JianFeng Ye YongBao Wu Lei Xue SEU-Monash Joint Graduate school Southeast University The College of Software Engineering Southeast University School of Automation Southeast UniversityKey Laboratory of Measurement and Control of Complex Systems of EngineeringMinistry of Education

ISBN: (数字)9789887581536

ISBN: (纸本)9781665482561

This paper studies a classical single pursuer and single evader pursuit-evasion *** pursuer attempts to capture the slower evader who aims to extend its lifetime during the *** simplify this question,requiring the evader to take fixation strategy which is choosing the farthest point in its current dominant region as aimpoint and moving at a constant *** the pursuer is faster than the ***,the speed ratio is a *** instaneous state space will be partitioned into pursuer's dominant zone and evader's dominant zone by the generalized Apollonius *** pursuit strategy is based on minimizing the area of the evader's dominant ***,we propose a supermodular game for this ***,the existence of the Nash equilibrium is *** results based on Q-learning are presented to solve the problem,which shows the effectiveness of this method.

关键词： Pursuit-evasion game Nash equilibrium Q-learning

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Optimized Hybrid Control for Attitude Adjustment of Downhole Directional Drilling Tools 50

Optimized Hybrid Control for Attitude Adjustment of Downhole...

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50th Annual Conference of the IEEE Industrial Electronics Society, IECON 2024

作者： Xiao, Jing Wang, She Cai, Zhen School of Information Engineering Wuhan City Polytechnic University Wuhan430064 China Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems Wuhan430074 China

ISBN: (纸本)9781665464543

This study delves into the critical role of attitude control in downhole directional drilling tools, focusing on the complex coupling between inclination and azimuth in the motion model, particularly the time-varying nature of azimuth adjustments. By implementing separate control strategies for inclination and azimuth, the research integrates a comprehensive hybrid control system. It rigorously examines the stability of the closed-loop systems and validates the effectiveness and applicability of the hybrid control method through extensive simulations. The system demonstrates significant robustness and adaptability, enhancing drilling precision and efficiency. © 2024 IEEE.

关键词： State feedback

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