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Enhanced strength-ductility synergy in a gradient pseudo-precipitates heterostructured Al-2.5%Mg alloy:Design,fabrication,and deformation mechanism

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Journal of Materials science & Technology 2024年第29期196卷 88-100页

作者： Renhao Wu Yeon Taek Choi Qingfeng Wu Xinxi Liu Dayong An Tianle Li Meng Li Hyoung Seop Kim Department of Plasticity Technology School of Materials Science&EngineeringShanghai Jiao Tong UniversityShanghai 200030China Graduate Institute of Ferrous&Eco Materials Technology Pohang University of Science and Technology37673South Korea Department of Materials Science and Engineering Pohang University of Science and Technology(POSTECH)37673South Korea School of Materials Science&Engineering Changsha University of Science&TechnologyChangsha 410114China Advanced Institute for Materials Research(WPI-AIMR) Tohoku UniversitySendai 980-8577Japan Institute for Convergence Research and Education in Advanced Technology Yonsei UniversitySeoul 03722South Korea

Heterostructures of alloyed composites,comprising heterogeneous domains with dramatically different constitutive properties,hold remarkable potential to expand the realm of material design systems and resolve the tradeoffbetween strength and *** study introduces an innovative materials design method for synthesizing gradient pseudo-precipitates heterostructure(GPHS)in non-heat-treatable Al-2.5%Mg *** cost-effective mild steel as both the diffusion source and protective layer,this heterostructure is achieved through pin-less friction stir-assisted cyclic localized deformation *** Fe atoms diffuse across the interface by friction stir-induced heat conduction,forming Fe-Al second-phase particles in the Al alloy matrix.A rapid inter-diffusion mechanism is activated in conjunction with dense dislocation walls,grain boundaries,and sub-structures,resulting in the formation of *** pseudo-precipitates are ultimately dispersed in a gradient distribution throughout the entire thickness of the Al alloy matrix induced by localized incremental *** GPHSed Al-2.5%Mg alloy exhibits an enhanced synergy of strength and ductility,with a uniform elongation increase from 11%to 21.2%,while maintaining the *** strengthening and hardening mechanisms,such as solid solution strengthening,dislocation hardening,and second phase strengthening,work synergistically to promote mechanical ***,the hetero-deformation between hard pseudo-precipitates and soft Al alloy matrix induces additional strain hardening,leading to high *** work provides a fresh perspective on the design and fabrication of high-performance alloys with advanced heterostructures,especially for non-heat-treatable alloys.

关键词： Gradient pseudo-precipitates heterostructure Enhanced strength-ductility synergy Rapid diffusion Hetero-deformation induced strain hardening Al-2.5%Mg alloy

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Unsupervised Episode Generation for Graph Meta-learning 41

Unsupervised Episode Generation for Graph Meta-learning

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41st International Conference on Machine Learning, ICML 2024

作者： Jung, Jihyeong Seo, Sangwoo Kim, Sungwon Park, Chanyoung Department of Industrial & Systems Engineering KAIST Korea Republic of Graduate School of Data Science KAIST Korea Republic of

We propose Unsupervised Episode Generation method called Neighbors as Queries (NAQ) to solve the Few-Shot Node-Classification (FSNC) task by unsupervised Graph Meta-learning. Doing so enables full utilization of the information of all nodes in a graph, which is not possible in current supervised meta-learning methods for FSNC due to the label-scarcity problem. In addition, unlike unsupervised Graph Contrastive Learning (GCL) methods that overlook the downstream task to be solved at the training phase resulting in vulnerability to class imbalance of a graph, we adopt the episodic learning framework that allows the model to be aware of the downstream task format, i.e., FSNC. The proposed NAQ is a simple but effective unsupervised episode generation method that randomly samples nodes from a graph to make a support set, followed by similarity-based sampling of nodes to make the corresponding query set. Since NAQ is model-agnostic, any existing supervised graph meta-learning methods can be trained in an unsupervised manner, while not sacrificing much of their performance or sometimes even improving them. Extensive experimental results demonstrate the effectiveness of our proposed unsupervised episode generation method for graph meta-learning towards the FSNC task. Our code is available at: https://***/JhngJng/NaQ-PyTorch. Copyright 2024 by the author(s)

关键词： Contrastive Learning

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Posture Prediction in Response to Seat Angle Change with Smart Chair

Posture Prediction in Response to Seat Angle Change with Sma...

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2024 IEEE International Conference on systems, Man, and Cybernetics, SMC 2024

作者： Esumi, Tsubasa Takemura, Noriko Graduate School of Computer Science and Systems Engineering Kyushu Institute of Technology Department of Artificial Intelligence Fukuoka Japan

ISBN: (纸本)9781665410205

Long-term desk work with lousy posture causes physical disabilities. To solve this problem, we have developed a smart chair with a controllable seat angle in our previous research. In order to control the seat angle and guide the user to the correct posture using this smart chair, it is necessary to investigate how the posture changes in response to the seat angle change. In this study, we first constructed a dataset by capturing posture data from 30 subjects while changing the seat angle of the smart chair. This dataset trained a model based on a graph neural network to predict posture in response to seat angle changes. We compared the model's prediction performance in the evaluation experiment depending on the training data and the body part. © 2024 IEEE.

关键词： Graph neural networks

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Two-tier control structure design methodology applied to heat exchanger networks

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Chinese Journal of Chemical engineering 2022年第7期35卷 231-244页

作者： Siwen Gu Lei Zhang Yu Zhuang Weida Li Jian Du Cheng Shao Institute of Chemical Process Systems Engineering School of Chemical EngineeringDalian University of TechnologyDalian 116024China Jiangsu Collaborative Innovation Center for Cultural Creativity School of Photoelectric EngineeringChangzhou Institute of TechnologyChangzhou 213032China Institute of Advanced Control Technology School of Control Science and EngineeringDalian University of TechnologyDalian 116024China

Because of its paramount importance in the successful industrial control strategy of a given heat exchanger network(HEN),the control structure designs for providing appropriate manipulated variable(MV)and controlled variable pairings have received considerable ***,quite frequently HENs with such control structures face the problem of hard constraints,typically holding the HENs at less controlled operating *** both the MV pairings and the above control pairings should be considered to design a control *** paper investigates the systematic incorporation of the two pairings,and presents a methodology for designing such two-tier control *** is developed based on the sequential strategy,coupling an indirect-tier with direct-tier control structure design,wherein the intention is realized in the former stage and the latter is implemented for further *** MV identification and pairing are achieved through variations in heat load of heat exchangers to design the indirect-tier control *** the direct-tier control structure is followed the relative gain array pairing *** the proposed methodology,on the one hand,it generates an explicit connection between the MV pairings and the HEN configuration,and the quantitative interaction measure is improved to avoid the multiple solutions to break the relationship among all the control pairings into individuals;on the other hand,a two-tier control structure reveals control potentials and control system design requirements,this may avoid complex and economically unfavourable control and HEN *** application of proposed framework is illustrated with two cases involving the dynamic simulation analysis,the quantitative assessment and the random test.

关键词： Heat exchanger networks(HENs) controllability Two-tier control structure Manipulated variable pairing control pairing

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The Robustness of a Twisted Prisoner's Dilemma for Incorporating Memory and Unlikeliness of Occurrence 9

The Robustness of a Twisted Prisoner's Dilemma for Incorpora...

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9th International Conference on Complexity, Future Information systems and Risk, COMPLEXIS 2024

作者： Takahara, Akihiro Sakiyama, Tomoko Graduate School of Science and Engineering Soka University Hachioji Japan Department of Information Systems Science Soka University Hachioji Japan

ISBN: (纸本)9789897586989

In classical game theory, because players having Defector (D) strategy tend to survive, many studies have been conducted to determine the survival of players with Cooperator (C) strategy. Recently, we have tackled the problem of the evolution of cooperators by proposing a new model called the twisted prisoner's dilemma (TPD) model. In the proposed model, each player is given a memory length. In situations where neighbors had the same strategy as a player and a higher score than that of the player, the player updated their strategy by ignoring the classical SPD update rule. This new strategy was difficult to choose before the update. Consequently, cooperators could survive even if their memory length was small. In this study, by focusing on the system sizes, performance of the TPD model was determined. Similar results were obtained for various system sizes, except when the system size was extremely small. Copyright © 2024 by SCITEPRESS - science and Technology Publications, Lda.

关键词： Game theory

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Reinforcement learning-based unknown reference tracking control of HMASs with nonidentical communication delays

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science China(Information sciences) 2023年第7期66卷 46-57页

作者： Yong XU Zheng-Guang WU Wei-Wei CHE Deyuan MENG School of Automation Beijing Institute of Technology Institute of Cyber-Systems and Control Zhejiang University College of Mathematics and Computer Science Zhejiang Normal University Department of Automation Qingdao University School of Automation Science and Electrical Engineering Beihang University(BUAA)

This paper focuses on the optimal output synchronization control problem of heterogeneous multiagent systems(HMASs) subject to nonidentical communication delays by a reinforcement learning *** with existing studies assuming that the precise model of the leader is globally or distributively accessible to all or some of the followers, the leader's precise dynamical model is entirely inaccessible to all the followers in this paper. A data-based learning algorithm is first proposed to reconstruct the leader's unknown system matrix online. A distributed predictor subject to communication delays is further devised to estimate the leader's state, where interaction delays are allowed to be nonidentical. Then, a learning-based local controller, together with a discounted performance function, is projected to reach the optimal output synchronization. Bellman equations and game algebraic Riccati equations are constructed to learn the optimal solution by developing a model-based reinforcement learning(RL) algorithm online without solving regulator equations, which is followed by a model-free off-policy RL algorithm to relax the requirement of all agents' dynamics faced by the model-based RL algorithm. The optimal tracking control of HMASs subject to unknown leader dynamics and communication delays is shown to be solvable under the proposed RL algorithms. Finally, the effectiveness of theoretical analysis is verified by numerical simulations.

关键词： heterogeneous multiagent systems HMAS reinforcement learning RL optimal output synchronization communication delays

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Exploring Respiratory Parameters Related to Psychophysiological Indexes of Mental Health

Exploring Respiratory Parameters Related to Psychophysiologi...

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2023 IEEE International Symposium on Medical Measurements and Applications, MeMeA 2023

作者： Suzuki, Miyu Sato, Hiroki Shibaura Institute of Technology Saitama Systems Engineering and Science Graduate School of Engineering and Science Japan Shibaura Institute of Technology Saitama College of Systems Engineering and Science Department of Bioscience and Engineering Japan

ISBN: (纸本)9781665493840

Psychophysiological indexes based on questionnaire scores and heart rate variability analysis are widely used as mental health indexes. In this study, we focused on respiratory information and aimed to explore respiratory parameters related to psychophysiological indexes of mental health. Seven respiratory parameters were used: respiratory rate, inhalation time, exhalation time, exhalation-inhalation ratio, inhalation time variability, exhalation time variability, and exhalation-inhalation ratio variability. Furthermore, the seven respiratory parameters were analyzed using representative psychophysiological indexes: relaxation scale, anxiety scale (STAI), sleep scale (PSQI-J), and pulse wave, EEG. Twenty-eight university students participated in the experiment. Simultaneous measurements with a band-type respiration sensor, an optical pulse wave sensor, and an electrode-type EEG sensor were performed for 5 min in a resting state after obtaining answers to each questionnaire, and finally, answers to the questionnaires were obtained again. A correlation analysis of the respiratory parameters and psychophysiological indexes revealed a positive correlation (r=0.41 and r=0.44, respectively) between state anxiety and the variability of inhalation and exhalation times (p © 2023 IEEE.

关键词： Sleep research

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Mobile Robot Manipulator Localization in Indoor Environments for Object Picking Tasks 6

Mobile Robot Manipulator Localization in Indoor Environments...

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6th International Conference on control and Robotics, ICCR 2024

作者： Xie, Yunfan Pongthanisorn, Goragod Kaneko, Shin-Ichiro Capi, Genci Graduate School of Science and Engineering Hosei University Dept. of Mechanical Eng. Tokyo Japan National Institute of Technology Toyama College Department of Electrical and Control Systems Engineering Toyama Japan

ISBN: (纸本)9798331518158

In dynamic and unpredictable work environments such as manufacturing, logistics, and automated warehouses, achieving high-precision self-localization estimation for efficient object picking are critical challenges for mobile robots. Ensuring accuracy and adaptability is essential for their successful operation. This paper presents a new method that integrates RGB cameras with Contrastive Learning (CL) for self-localization estimation and advanced object picking for mobile manipulators. The effectiveness of the proposed method for location estimation in object picking is verified in indoor environments. © 2024 IEEE.

关键词： Contrastive Learning

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Event-triggered consensus control of heterogeneous multi-agent systems: model-and data-based approaches

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science China(Information sciences) 2023年第9期66卷 151-167页

作者： Xin WANG Jian SUN Fang DENG Gang WANG Jie CHEN School of Automation Beijing Institute of Technology National Key Lab of Autonomous Intelligent Unmanned Systems Beijing Institute of Technology Chongqing Innovation Center Department of Control Science and Engineering Tongji University

This article addresses the model-and data-based event-triggered consensus of heterogeneous leader/follower multi-agent systems(MASs). A dynamic periodic transmission protocol is developed to alleviate the communication and computational burden, where the followers can interact locally with neighbors to approach the dynamics of the leader. Capitalizing on a discrete-time looped-functional, a model-based consensus condition for the closed-loop MASs is derived as linear matrix inequalities(LMIs), along with a design method for obtaining distributed event-triggered controllers and the associated triggering *** collecting noise-corrupted state-input measurements in offline open-loop experiments, a data-based leader/follower MAS representation is derived and employed to address the data-driven consensus control problem without explicit MAS models. This result is subsequently generalized to guarantee an H∞-consensus control performance. Finally, a simulation example is given to corroborate the efficiency of the proposed distributed triggering scheme and the data-driven consensus controller.

关键词： data-driven control multi-agent system consensus looped-functional LMI

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Impact of Competition on the Relationship Between Relative Performance and Motivation to Develop Radical Technology

Impact of Competition on the Relationship Between Relative P...

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2024 IEEE International Conference on Industrial engineering and engineering Management, IEEM 2024

作者： Meguro, S. Takahashi, N. Ouchi, N. Graduate School of Science and Engineering Aoyama Gakuin University Sagamihara Japan Department of Industrial and Systems Engineering Aoyama Gakuin University Sagamihara Japan

ISBN: (纸本)9798350386097

Two types of technology development are conducted by firms: radical and incremental. While many studies have focused on the circumstances when firms actively conduct high-risk radical technology development, they have demonstrated that the more a firm’s technological performance rises above or falls below its aspiration, the more reluctant it is to try radical technology development. Moreover, some studies have suggested that the propensity of a firm’s technology development varies with the intensity of competition. Given these findings, our study aimed to clarify the following: 1) the impact of the difference between a firm’s technological performance and its aspiration on the firm’s effort to radical technology development;2) how this impact varies with the intensity of competition, using patent data. Firms’ efforts to radical technology development were measured by the number of radical patents extracted using patent citation relationships. The performance and aspiration of firms were measured by the number of forward citations of their patents. This study revealed that the negative impact that occurs when performance falls below aspiration was stronger in more competitive technology areas. © 2024 IEEE.

关键词： competition patent data Radical technology

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