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Image categorization with resource constraints： introduction, challenges and advances

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Frontiers of Computer Science 2017年第1期11卷 13-26页

作者： jian-hao LUO Wang ZHOU jianxin WU National Key Laboratory for Novel Software Technology Nanjing University Nanjing 210023 China

As one of the most classic fields in computer vi- sion, image categorization has attracted widespread interests. Numerous algorithms have been proposed in the community, and many of them have advanced the state-of-the-art. How- ever, most existing algorithms are designed without consider- ation for the supply of computing resources. Therefore, when dealing with resource constrained tasks, these algorithms will fail to give satisfactory results. In this paper, we provide a comprehensive and in-depth introduction of recent develop- ments of the research in image categorization with resource constraints. While a large portion is based on our own work, we will also give a brief description of other elegant algo- rithms. Furthermore, we make an investigation into the re- cent developments of deep neural networks, with a focus on resource constrained deep nets.

关键词： image categorization resource constraints,large scale classification deep neural networks

Electronic transport properties of Co cluster-decorated graphene

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Chinese Physics B 2018年第6期27卷 81-86页

作者： Chao-Yi Cai jian-hao Chen International Center for Quantum Materials Peking UniversityCollaborative Innovation Center of Quantum Matte

Interactions of magnetic elements with graphene may lead to various electronic states that have potential *** report an in-situ experiment in which the quantum transport properties of graphene are measured with increasing cobalt coverage in continuous ultra-high vacuum environment. The results show that e-beam deposited cobalt forms clusters on the surface of graphene, even at low sample temperatures. Scattering of charge carriers by the absorbed cobalt clusters results in the disappearance of the Shubnikov–de Haas（Sd H） oscillations and the appearance of negative magnetoresistance（MR）which shows no sign of saturation up to an applied magnetic field of 9 T. We propose that these observations could originate from quantum interference driven by cobalt disorder and can be explained by the weak localization theory.

关键词： in situ quantum transport negative magnetoresistance weak localization

Influence of thermal ageing on high-field polarisation characteristics and conductivity behaviour of submarine polymeric cables insulation

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High Voltage 2023年第1期8卷 138-148页

作者： Xize Dai jian hao Gian Carlo Montanari Zheng jian Ruijin Liao Xinlong Zheng State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina Department of Energy Aalborg UniversityAalborgDenmark Center for Advanced Power Systems Florida State UniversityTallahasseeFloridaUSA Shinan Power Supply Branch Company of State Grid Chongqing Electric Power Company NananChina Zhoushan Power Supply Branch Company of State Grid Zhejiang Electric Power Company ZhoushanChina

Diagnosing insulation intrinsic ageing is essential for preventing insulation failure of submarine cables,and in case of failure,helping in any decision about maintenance *** this study,a novel aged cable diagnosis approach based on high-voltage frequency domain spectroscopy(HV-FDS)with broader frequency width is proposed to analyse the high-field polarisation characteristics and conductivity behaviour of 500 kV submarine polymeric cables insulation,aiming to support the evaluation of overall insulation *** measurement principle of HV-FDS and relaxation mechanism are stated,and then focus is on studying the extent of change of polarisation and conduction properties of submarine cables insulation as a function of ageing stress and ***,the high-field polarisation characteristics and conductivity behaviour are discussed in-depth based on the carrier transport and trap ***,the novel diagnostic indicator based on the high-field characteristics is extracted to quantify the thermal ageing state of submarine cables *** show that the high-field polarisation characteristics and conductivity behaviour seem to become sensitive diagnostic quantities if measured at reasonably high voltage,which are able to reveal mechanisms associated with thermo-oxidative ageing as that generated in the testing procedure considered in this *** is considerably higher than that experienced in typical dielectric spectroscopy approaches.

关键词： behaviour insulation characteristics

Terminal Sliding Mode Control for Cyber Physical System Based on Filtering Backstepping

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International Journal of Automation and computing 2015年第5期12卷 497-502页

作者： Fei Li jian-Bo Hu Lei Zheng jian-hao Wang Equipment Management and Safety Engineering College Air Force Engineering University Unit 93286 People's Liberation Army

Based on a nonlinear flight dynamic model with aerodynamic coefficients and external disturbance uncertainties, which is a typical cyber physical system, a filtering backstepping terminal sliding mode control method is proposed for a robust *** tracking differentiator can provide the capability of solving the problem of 'complexity explosion' in backstepping controllers to simplify the backstepping implementation. Nonlinear disturbance observers are used to observe the uncertainties of the nonlinear flight dynamic system. The terminal sliding mode controller is designed to improve its convergence rate and the tracking accuracy. Finally,nonlinear 6-degree-of-freedom simulation results for an F-16 aircraft model elaborate the effectiveness of the proposed control system.

关键词： Cyber-physical system(CPS) disturbance uncertainti

A boundary layer model for capture of inclusions by steel-slag interface in a turbulent flow

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Journal of Iron and Steel Research International 2023年第6期30卷 1101-1108页

作者： Yi-peng Sun hao-jian Duan Li-feng Zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

A boundary layer model was developed to predict the capture of inclusions by steel-slag interface in a turbulent fluid flow,which is based on the detailed analysis of inclusion *** effective boundary layer for inclusion removal was proposed by a statistical *** is noticed that the capture of inclusions by steel-slag interface is not only dependent on the diameter of inclusions but also related to the local turbulent *** high turbulent flow fields,the transport of inclusions is mainly dominated by the turbulent flow,and thus,the effective boundary layer thickness is mainly affected by the level of turbulent kinetic energy and is almost independent of the inclusion *** inertia of inclusions gradually takes over the stochastic effect of turbulent flow,and the effect of inclusion diameter on effective boundary layer thickness becomes more noticeable with the decrease in the level of turbulent kinetic ***,the effective boundary layer thickness is more susceptible to the inclusion diameter for larger inclusions due to its greater inertia under the same turbulent condition while it principally depends on the level of turbulent kinetic energy for smaller *** the characteristic velocity increases,the time for inclusions transport and interaction with steel-slag interface decreases,and thus,the effective boundary layer thickness ***,the graphical user interface was developed by using the cubic spline interpolation for ease of coupling the current boundary layer model with the macro-scale model of a turbulent fluid flow in the metallurgical vessel.

关键词： Boundary layer model Capture of inclusions steel–slag interface Turbulent flow

Efficient Multiagent Policy Optimization Based on Weighted Estimators in Stochastic Cooperative Environments

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Journal of Computer Science & Technology 2020年第2期35卷 268-280页

作者： Yan Zheng jian-Ye hao Zong-Zhang Zhang Zhao-Peng Meng Xiao-Tian hao College of Intelligence and Computing Tianjin UniversityTianjin 300350China National Key Laboratory for Novel Software Technology Nanjing UniversityNanjing 210023China

Multiagent deep reinforcement learning (MA-DRL) has received increasingly wide attention. Most of the existing MA-DRL algorithms, however, are still inefficient when faced with the non-stationarity due to agents changing behavior consistently in stochastic environments. This paper extends the weighted double estimator to multiagent domains and proposes an MA-DRL framework, named Weighted Double Deep Q-Network (WDDQN). By leveraging the weighted double estimator and the deep neural network, WDDQN can not only reduce the bias effectively but also handle scenarios with raw visual inputs. To achieve efficient cooperation in multiagent domains, we introduce a lenient reward network and scheduled replay strategy. Empirical results show that WDDQN outperforms an existing DRL algorithm (double DQN) and an MA-DRL algorithm (lenient Q-learning) regarding the averaged reward and the convergence speed and is more likely to converge to the Pareto-optimal Nash equilibrium in stochastic cooperative environments.

关键词： deep reinforcement learning multiagent system weighted double estimator lenient reinforcement learning cooperative Markov game

Tensile and compressive behavior of Ti-based bulk metallic glass composites

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 582-588页

作者： Yong-sheng Wang Guo-jian hao Jun-pin Lin State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

This article focuses on the tensile and compressive characteristics of a Ti-based bulk metallic glass composite （BMGC）. It is found that the yield stress, maximum strength, and fracture strain are 1380 MPa, 1516 MPa, and 4.3% for uniaxial tension, but 1580 MPa, 4010 MPa, and 29% for uniaxial compression, respectively. The composite displays a linear ＂work hardening＂ capacity under compression; however, the ＂work softening＂ behavior is observed in the true engineering stress-strain curve upon tensile loading. The fracture surfaces of specimens also exhibit dissimilar properties under the different loadings.

关键词： metallic glass composite materials tensile testing compression testing fracture

Snowpack variations and their hazardous effects under climate warming in the central Tianshan Mountains

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Advances in Climate Change Research 2024年第3期15卷 442-451页

作者： jian-Sheng hao Yan WANG Lan-Hai LI Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences(CAS)Beijing 100101China Xinjiang Key Laboratory of Water Cycle and Utilization in Arid Zone Urumqi 830011China State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China Tianshan Snowcover and Avalanche Observation and Research Station of Xinjiang Xinyuan 835800China CAS Research Center for Ecology and Environment of Central Asia Urumqi 830011China

Climate change alters snowpack evolution,which in turn influences the likelihood of snow avalanches and flood *** lack of systemic observational data on key snow characteristics in high mountains remains a scientific challenge in terms of systematically elucidating the dynamic chain of variations in climate-snowpack-snow *** restricts our understanding and poses challenges in the prediction of snow-related disaster *** such,this study analysed the variations of temperature and snowfall and the physical characteristics of snowpacks based on ground-based observations from the Kunse River Valley situated in the Tianshan Mountains from 1967 to *** results reveal that the temperature increased significantly by 0.32°C per decade(p<0.01)during the snow season,along with more extreme snowfall *** snow-cover duration was observed to have been shortened by 4.77 d per decade(p<0.01)from 1967 to 2021,which is characterised by later snow-cover onset and earlier ***,average and maximum snow depths increased along with an increase in peak snow water equivalent,thus indicating a higher frequency of extremely scarce or abundant snow *** low snowpack temperature gradient and earlier snowmelt dates in spring lead to earlier occurrences of snowmelt floods and wet *** the risks of these events increase,they pose greater threats to farmlands,road transportation,water-electricity infrastructure and several other human ***,these insights are critical for providing vital information that can deepen our understanding of the impact of climate change on snowpack characteristics and improve management strategies for snow-related disaster prevention and mitigation.

关键词： Climate change Snowpack variations Snow-related disaster Tianshan Mountains

Numerical Studies on the Generation and Propagation of Tsunami Waves Based on the High-Order Spectral Method

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China Ocean Engineering 2022年第2期36卷 268-278页

作者： hao jian LI Jin-xuan LIU Shu-xue WANG Lei State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

An effective numerical model for wave propagation over three-dimensional(3D)bathymetry was developed based on the High-Order Spectral(HOS)method and combined with a moving bottom *** on this model,tsunami waves caused by various mechanisms were simulated and ***-dimensional bed upthrust and the effect of the uplift velocity of the bathymetry on the wave profiles of tsunami waves were ***,tsunami waves caused by 3D submarine slides were generated and the effects of the slide velocity,slide dimension and water depth on the tsunami waves were *** on wavelet analysis,the properties of the tsunami wave propagation were *** results show that the bottom movement can significantly affect the generation and propagation of tsunami waves and the studies could help understand the mechanisms of tsunamis caused by a moving bottom boundary.

关键词： tsunami waves High-Order Spectral(HOS)method moving bottom boundary wavelet analysis