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Exoskeleton active assistance strategy for human muscle activation reduction during linear and circular walking

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Advances in Manufacturing 2024年第3期12卷 484-496页

作者： wen-Tao Sheng Ke-Yao Liang Hai-Bin Tang School of Intelligent Manufacturing Nanjing University of Science and TechnologyNanjing210094People’s Republic of China School of Mechatronics Engineering Harbin Institute of TechnologyHarbin150001People’s Republic of China

The exoskeleton is employed to assist humans in various domains including military missions,rehabilitation,industrial operation,and activities of daily living(ADLs).Walking is a fundamental ADL,and exoskeletons are capable of reducing the activation and metabolism of lower extremity muscles through active assistance during *** improve the performance of active assistance strategy,this article proposes a framework using an active hip ***,it correlates to an already established Bayesian-based human gait recognition algorithm,with a particular focus on linear and circular walking within industrial and ADL *** theorizing this strategy for exoskeletons,this study further reveals,in part,the activation characteristics of human hip muscles for the instruction and regulation of active assistance duration and onset *** proposed active assistance strategy provides new insights for enhancing the performance of assistive robots and facilitating human robot interaction within the context of ADLs.

关键词： Human-robot interaction Hip exoskeleton Muscle activation Walking assistance

Deformation mechanism and hydrocarbon significance of Eocene organic-rich fine-grained soft sediments in the Leijia Region,Liaohe Depression

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Frontiers of Earth Science 2024年第1期18卷 83-97页

作者： Yijie wen Jianguo ZHANG Shu TAO Chenyu CAI School of Energy Resources China University of Geosciences(Beijing)Beijing 100083China Key Laboratory of Strategy Evaluation for Shale Gas(Ministry of Land Resources) China University of Geosciences(Beijing)Beijing 100083China School of Foreign Languages China University of Geosciences(Beijing)Beijing 100083China

The deformation structure of soft sediments has always been a research hotspot,which is of great significance for analyzing the tectonic and sedimentary evolution background of a basin,as well as the physical properties of *** studies have reported that a large number of soft sediment deformation structures are developed in the western part of Liaohe *** this study,through core observation and thin section identification,various types of deformation structures are identified in the core samples which are collected from the upper Es4 in the Leijia region,western sag of Liaohe depression,such as liquefied dikes,liquefied breccia,convoluted laminae,annular bedding,synsedimentary faults,vein structures,*** on the characteristics of core structure,single well profile and continuous well profile,combined with the regional background,this study clarifies that the deformation structure of soft sediments in the study area is mainly caused by seismic *** is found that the permeability and porosity of deformation layers in the study area are higher than those of the undeformation layers,which proves that the deformation structure of soft sediments has a good effect on improving the physical properties of reservoirs.

关键词： soft sediment deformation structure Liaohe depression organic-rich fine-grained soft sediments hydrocarbon significance

Solvent-free carbon sphere nanofluids towards intelligent lubrication regulation

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Friction 2024年第1期12卷 95-109页

作者： Sheng ZHANG wen LI Xiaoliang MA Xiaoqiang FAN Minhao ZHU Tribology Research Institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

By simply switching the electrical circuit installed on steel/steel contact,the tribological behaviors of nanofluids(NFs)can be regulated in real time,thereby achieving the desired performance of friction reduction and wear ***,solvent-free carbon spherical nanofluids(C-NFs)were successfully prepared for intelligent lubrication regulation.C-NFs with excellent lubrication performance can immediately reduce the coefficient of friction(COF)despite applying a weak electric potential(1.5 V).Moreover,polyethylene glycol 400(PEG400)containing 5.0 wt%C-NFs remained responsive to electrical stimulation under the intermittent voltage application with an average coefficient of friction(ACOF)reduction of 20.8%over *** intelligent lubrication regulation of C-NFs under an external electric field(EEF)mainly depends on the orderly arranged double-electric adsorption film of ion canopy-adsorbed carbon spheres(CSs).The intermittent electrical application can continuously reinforce the adsorption film and its durability for real-time controlling the sliding ***-stimulation-responsive intelligent lubricants provide a new technical support for realizing intelligent stepless control of devices.

关键词： solvent-free carbon spherical nanofluids(C-NFs) intelligent lubrication regulation lubrication performance adsorption film

Asymmetric Drying and Wetting Trends in Eastern and Western China

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Advances in Atmospheric Sciences 2024年第2期41卷 221-232页

作者： wen WU Fei JI Shujuan HU Yongli HE College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000China Collaborative Innovation Center for Western Ecological Safety Lanzhou UniversityLanzhou 730000China

As an important factor that directly affects agricultural production, the social economy, and policy implementation,observed changes in dry/wet conditions have become a matter of widespread concern. However, previous research has mainly focused on the long-term linear changes of dry/wet conditions, while the detection and evolution of the non-linear trends related to dry/wet changes have received less attention. The non-linear trends of the annual aridity index, obtained by the Ensemble Empirical Mode Decomposition(EEMD) method, reveal that changes in dry/wet conditions in China are asymmetric and can be characterized by contrasting features in both time and space in China. Spatially, most areas in western China have experienced transitions from drying to wetting, while opposite changes have occurred in most areas of eastern China. Temporally, the transitions occurred earlier in western China compared to eastern China. Research into the asymmetric spatial characteristics of dry/wet conditions compensates for the inadequacies of previous studies, which focused solely on temporal evolution;at the same time, it remedies the inadequacies of traditional research on linear trends over centennial timescales. Analyzing the non-linear trend also provides for a more comprehensive understanding of the drying/wetting changes in China.

关键词： aridity index EEMD dry/wet conditions asymmetric evolution

An Adaptive Hybrid Optimization Strategy for Resource Allocation in Network Function Virtualization

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Computer Modeling in Engineering & Sciences 2024年第2期138卷 1617-1636页

作者： Chumei wen Delu Zeng School of Mathematics South China University of TechnologyGuangzhou510640China School of Electronic and Information Engineering South China University of TechnologyGuangzhou510640China

With the rapid development of Network Function Virtualization(NFV),the problem of low resource utilizationin traditional data centers is gradually being ***,existing research does not optimize both localand global allocation of resources in data ***,we propose an adaptive hybrid optimization strategy thatcombines dynamic programming and neural networks to improve resource utilization and service quality in *** approach encompasses a service function chain simulation generator,a parallel architecture servicesystem,a dynamic programming strategy formaximizing the utilization of local server resources,a neural networkfor predicting the global utilization rate of resources and a global resource optimization strategy for bottleneck andredundant *** the implementation of our local and global resource allocation strategies,the systemperformance is significantly optimized through simulation.

关键词： NFV resource allocation decision-making optimization service function

Monte Carlo Simulation-Based Robust Workflow Scheduling for Spot Instances in Cloud Environments

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Tsinghua Science and Technology 2024年第1期29卷 112-126页

作者： Quanwang Wu Jianzhao Fang Jie Zeng Junhao wen Fengji Luo College of Computer Science Chongqing UniversityChongqing 400044China National Experimental Teaching Demonstration Center Chongqing UniversityChongqing 400044China College of Big Data and Software Engineering Chongqing UniversityChongqing 400044China School of Civil Engineering The University of SydneySydney 2006Australia

When deploying workflows in cloud environments,the use of Spot Instances(SIs)is intriguing as they are much cheaper than on-demand ***,Sls are volatile and may be revoked at any time,which results in a more challenging scheduling problem involving execution interruption and hence hinders the successful handling of conventional cloud workflow scheduling *** some scheduling methods for Sls have been proposed,most of them are no more applicable to the latest Sls,as they have evolved by eliminating bidding and simplifying the pricing *** study focuses on how to minimize the execution cost with a deadline constraint when deploying a workflow on volatile Sls in cloud *** on Monte Carlo simulation and list scheduling,a stochastic scheduling method called MCLS is devised to optimize a utility function introduced for this *** the Monte Carlo simulation framework,MCLS employs sampled task execution time to build solutions via deadline distribution and list scheduling,and then returns the most robust solution from all the candidates with a specific evaluation mechanism and selection *** results show that the performance of MCLS is more competitive comparedwithtraditionalalgorithms.

关键词： constrained optimization Monte Carlo simulation robustness Spot Instances(Sls) workflow scheduling

Exploring deep learning for landslide mapping:A comprehensive review

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China Geology 2024年第2期7卷 330-350页

作者： Zhi-qiang Yang wen-wen Qi Chong Xu Xiao-yi Shao College of Surveying and Geo-Informatics Tongji UniversityShanghai 200092China National Institute of Natural Hazards Ministry of Emergency ManagementBeijing 100085China Key Laboratory of Compound and Chained Natural Hazards Dynamics Ministry of Emergency Management of ChinaBeijing 100085China

A detailed and accurate inventory map of landslides is crucial for quantitative hazard assessment and land *** methods relying on change detection and object-oriented approaches have been criticized for their dependence on expert knowledge and subjective *** advancements in highresolution satellite imagery,coupled with the rapid development of artificial intelligence,particularly datadriven deep learning algorithms(DL)such as convolutional neural networks(CNN),have provided rich feature indicators for landslide mapping,overcoming previous *** this review paper,77representative DL-based landslide detection methods applied in various environments over the past seven years were *** study analyzed the structures of different DL networks,discussed five main application scenarios,and assessed both the advancements and limitations of DL in geological hazard *** results indicated that the increasing number of articles per year reflects growing interest in landslide mapping by artificial intelligence,with U-Net-based structures gaining prominence due to their flexibility in feature extraction and ***,we explored the hindrances of DL in landslide hazard research based on the above research *** such as black-box operations and sample dependence persist,warranting further theoretical research and future application of DL in landslide detection.

关键词： Landslide Mapping Quantitative hazard assessment Deep learning Artificial intelligence Neural network Big data Geological hazard survery engineering

Controlling underestimation bias in reinforcement learning via minmax operation

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Chinese Journal of Aeronautics 2024年第7期37卷 406-417页

作者： Fanghui HUANG Yixin HE Yu ZHANG Xinyang DENG wen JIANG School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China College of Information Science and Engineering Jiaxing UniversityJiaxing 314001China

Obtaining the accurate value estimation and reducing the estimation bias are the key issues in reinforcement ***,current methods that address the overestimation problem tend to introduce underestimation,which face a challenge of precise decision-making in many *** address this issue,we conduct a theoretical analysis of the underestimation bias and propose the minmax operation,which allow for flexible control of the estimation ***,we select the maximum value of each action from multiple parallel state-action networks to create a new state-action value ***,a minimum value is selected to obtain more accurate value ***,based on the minmax operation,we propose two novel algorithms by combining Deep Q-Network(DQN)and Double DQN(DDQN),named minmax-DQN and ***,we conduct theoretical analyses of the estimation bias and variance caused by our proposed minmax operation,which show that this operation significantly improves both underestimation and overestimation biases and leads to the unbiased ***,the variance is also reduced,which is helpful to improve the network training ***,we conduct numerous comparative experiments in various environments,which empirically demonstrate the superiority of our method.

关键词： Reinforcement learning Minmax operation Estimation bias Underestimation bias Variance

Regulating ion transport behaviors toward dendrite-free potassium metal batteries:recent advances and perspectives

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Rare Metals 2024年第4期43卷 1435-1460页

作者： Lu-Kang Zhao Xuan-wen Gao Tian-Zhen Ren Da Wang Da-Wei Wang Zhao-Meng Liu Hong Chen wen-Bin Luo School of Metallurgy Northeastern UniversityShenyang110819China School of Chemical Engineering The University of New South WalesSydneyNSW2052Australia

With abundant potassium resources and high capacity,potassium metal batteries(PMBs)present a compelling option for the next generation of energy storage ***,PMBs suffer from an unstable anode interface caused by uncontrolled dendrite growth,which results in unsatisfactory cyclability and safety *** investigations suggest that significant progress has been made in enhancing the interfacial stability of *** various effective strategies for stabilizing interfaces can ultimately be attributed to the regulation of the sluggish ion transfer kinetics and irregular deposition,i.e.,the arrangement of ion transport behaviors at the *** modulation of ions transport rate and ions deposition directions makes it possible to obtain a dendrite-free and smooth deposition ***,the influencing factors and action mechanism of K^(+)interface transport behaviors are discussed to understand the nature of material design for constructing stable anode interfaces,including regulating the solvation and desolvation structures,accelerating K^(+)transport kinetics and controlling K^(+)deposition *** addition,the deficiencies and prospects of the research on electrolyte,separators and designed electrode involved in the manufacturing and testing and ion transport process of PMBs are *** review is expected to provide some possible directions for constructing dendrite-free interfaces in advanced PMBs-related research and offer significant insights for prospective experimental research and commercial applications.

关键词： Ion transport rate Ion transport direction Interface Potassium metal batteries Dendrites growth