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基于上下文感知的强化学习AUV控制器研究

舰船科学技术 2024年第11期46卷 108-114页

作者：徐春晖徐德胜周仕昊杨士霖中国科学院沈阳自动化研究所机器人学国家重点实验室辽宁沈阳110016 中国科学院机器人与智能制造创新研究院辽宁沈阳110169 辽宁省水下机器人重点实验室辽宁沈阳110169 中国科学院大学北京100049

为了提升基于强化学习的自主水下航行器(Autonomous Underwater vehicle,AUV)控制器在复杂海况中对环境干扰的鲁棒性,设计一种利用上下文信息进行环境感知的强化学习控制器。结合水下机器人运动学及动力学方程对深度跟踪任务进行建模,... 详细信息

为了提升基于强化学习的自主水下航行器(Autonomous Underwater vehicle,AUV)控制器在复杂海况中对环境干扰的鲁棒性,设计一种利用上下文信息进行环境感知的强化学习控制器。结合水下机器人运动学及动力学方程对深度跟踪任务进行建模,构建了基于PPO-clip算法的深度控制器,并在算法中融入了上下文变量和域随机化方法。在仿真环境中分别进行海流干扰、暗涌干扰以及两者共同干扰环境的深度跟踪任务,仿真结果表明,本文提出的方法对强化学习控制器的抗干扰能力有明显的提升,在多种环境干扰下更精准地完成深度跟踪任务。

关键词： AUV 深度控制强化学习上下文感知

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城市居民应急避难可达性与公平性分析

科技和产业 2024年第17期24卷 336-340页

作者：李澳徐春辉吉林师范大学地理科学与旅游学院吉林四平136000

城市居民应急避难可达性与公平性分析可探究区域内应急资源布局的均衡性。以长春市城市居民应急避难公平性为研究对象,采用可达性模型与公平性模型,对研究区居民应急避难可达性与公平性进行分析。结果表明:长春市居民应急避难可达性高... 详细信息

城市居民应急避难可达性与公平性分析可探究区域内应急资源布局的均衡性。以长春市城市居民应急避难公平性为研究对象,采用可达性模型与公平性模型,对研究区居民应急避难可达性与公平性进行分析。结果表明:长春市居民应急避难可达性高值位于绿园区、宽城区、朝阳区、南关区、二道区5区交界地带;长春市洛伦兹曲线值很大程度上偏离绝对平均值曲线,基尼系数为0.6682,说明长春市的居民应急避难可达性处于高度不平均的状态。

关键词：应急避难可达性公平性洛伦兹曲线

Squeeze flow of interstitial Herschel-Bulkley fluid between two rigid spheres

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Particuology 2010年第4期8卷 360-364页

作者： chunhui xu Li Yuan Yong xu Wenbin Hang College of Science China Agricultural University Beijing 100083 China

Interaction between two spheres with an interstitial fluid is crucial in discrete element modeling for simulating the behaviors of ＇wet＇ particulate materials. The normal viscous force of squeeze flow between two arbitrary rigid spheres with an interstitial HerscheI-Bulkley fluid was studied on the basis of Reynolds＇ lubrication theory, resulting in analytical integral expressions of pressure distribution and the viscous force between the two spheres. According to the variation of shear stress, the fluid was divided into yielding and unyielding regions, followed by a discussion on the thickness of the two regions. The result of this paper could be reduced to either the power-law fluid or the Bingham fluid case.

关键词： Wet granuleDiscrete element method Herschel-Bulldey fluid Viscous force

2D DEM simulation of particle mixing in rotating drum: A parametric study

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Particuology 2010年第2期8卷 141-149页

作者： Yong xu chunhui xu Zhe Zhou Jing Du Daping Hu College of Sdence China Agricultural University Beijing 100083 China

Mixing behaviors of equal-sized glass beads in a rotating drum were investigated by both DEM simula- tions and experiments. The experiments indicated that higher rotation speed can significantly enhance mixing. The particle profiles predicted by 2D DEM simulation were compared with the experimental results from a quasi-2D drum, showing inconsistency due to reduction of contacts in the single-layer 2D simulation which makes the driving friction weaker than that in the quasi-2D test, better results could be reached by specifying a higher frictional coefficient between the particles and the cylinder wall. In order to explore the influences of physical properties （density, size or friction） on mixing behavior, numerical 2D simulations were carried out systematically, in which one examined specific property being examined was exaggerated while the others were kept the same as that in the control group. The DEM simulations reveal that particle density and size are the dominating factors affecting mixing behaviors, while the effect of frictional coefficient is less significant. However, segregation due to any of the factors can be diminished by specifying a proper particle size distribution （multi-size with lower size ratio）. 2009 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

关键词： Discrete Element Method Rotating drum Granule Mixing Mill Segregation

A New Method of Portfolio Optimization Under Cumulative Prospect Theory

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Tsinghua Science and Technology 2018年第1期23卷 75-86页

作者： Chao Gong chunhui xu Masakazu Ando Xiangming Xi Department of Risk Science in Finance and Management Chiba Institute of Technology Chiba 275-0016 Japan Department of Automation Tsinghua University Beijing 100084 China

In this paper, the portfolio selection problem under Cumulative Prospect Theory （CPT） is investigated and a model of portfolio optimization is presented. This model is solved by coupling scenario generation techniques with a genetic algorithm. Moreover, an Adaptive Real-Coded Genetic Algorithm （ARCGA） is developed to find the optimal solution for the proposed model. Computational results show that the proposed method solves the portfolio selection model and that ARCGA is an effective and stable algorithm. We compare the portfolio choices of CPT investors based on various bootstrap techniques for scenario generation and empirically examine the effect of reference points on investment behavior.

关键词： portfolio choice cumulative prospect theory bootstrap method adaptive real-coded genetic algorithm

The squeeze flow of a bi-viscosity fluid between two rigid spheres with wall slip

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Particuology 2023年第8期79卷 153-160页

作者： Tianyi Zhou Da Lin Yujia Shen Wei Yang chunhui xu xuedong Chen College of Science China Agricultural UniversityBeijing100083China Chinese Academy of Agricultural Mechanization Sciences Group Co. LtdBeijing100083China

In this paper,the squeeze flow between two rigid spheres with a bi-viscosity fluid is *** on lubrication theory,the squeeze force is calculated by deriving the pressure and velocity *** results of the normal squeeze force are discussed,and fitting functions of the squeeze and correction coefficients are *** squeeze force between the rigid spheres increases linearly or logarithmically with the velocity when most or part of the boundary fluid reaches the yield state,***,the slip correction coefficient decreases with the increase in the *** investigation may contribute to the further study of bi-viscosity fluids between rigid spheres with wall slip.

关键词： Squeeze flow Bi-viscosity fluid Rigid spheres Wall slip

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基于路网数据的应急避难所可达性分析

科技和产业 2024年第18期24卷 344-348页

作者：于欢欢徐春辉陈鹏吉林师范大学地理科学与旅游学院吉林四平136000

应急避难所的可达性反映了当自然灾害和紧急情况来临时人们紧急避难规避风险的便利程度。通过收集长春市中心城区道路、应急避难所位置以及人口数据,基于ArcGIS桌面软件采用核密度分析、OD(origin-destination)成本矩阵等方法,分析长春... 详细信息

应急避难所的可达性反映了当自然灾害和紧急情况来临时人们紧急避难规避风险的便利程度。通过收集长春市中心城区道路、应急避难所位置以及人口数据,基于ArcGIS桌面软件采用核密度分析、OD(origin-destination)成本矩阵等方法,分析长春市中心城区应急避难所的空间分布特征和可达性水平;对驾驶机动车和步行两种出行方式下不同时段到达避难所的人口进行了统计。结果表明,长春市中心城区的应急避难所设置较于集中,周边地区到应急避难所时间成本较高,区内少数人口受影响,应增设应急避难所。

关键词：应急避难所可达性 OD成本矩阵长春市中心城区

An unbalanced PD-L1/CD86 ratio in CD14^＋＋CD16^＋ monocytes is correlated with HCV viremia during chronic HCV infection

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Cellular & Molecular Immunology 2014年第3期11卷 294-304页

作者： Jiajia Zheng Hua Liang chunhui xu Qiang xu Ting Zhang Tao Shen Fengmin LU Department of Microbiology Peking University Health Science Center Beijing China Department of Laboratory Medicine Peking University Third Hospital Beijing China State Key Laboratory for infectious Disease Prevention and Control National Center for AIDS/STD Control and Prevention China CDC Beijing China Center of Infectious Diseases Peking University Beijing China These authors contributed equally to this work

Circulating monocyte subsets with distinct functions play important roles in hepatitis C virus （HCV） infection. However, the mechanisms have not been well studied. In this study, we analyzed the distributions and phenotypic characteristics of three circulating monocyte subsets--CD14^＋＋CD16^-, CD14^＋＋CD16^＋ and CD14^＋＋mCD16^——in chronic HCV-infected patients, HCV spontaneous resolvers and healthy controls, and we evaluated the possible link between HCV viremia and disease progression. Our results indicated that the frequency of the CD 14^＋＋CD 16^＋ monocyte subset was decreased, and negatively correlated with HCV RNA and core antigen levels during chronic HCV infection. PD-L1 expression and the PD-L1/CD86 ratio in CD14^＋＋CD16^＋ monocytes were higher during chronic HCV infection than in spontaneous HCV resolvers and healthy controls. The PD-L1/CD86 ratio positively correlated with HCV viral load and core antigen levels. Finally, PD-L1 was significantly increased, while cytokine secretions were dramatically decreased upon Toll-like receptor （TLR） ligand binding and HCV JFH-lstimulation. These findings indicates the compromised immune status of the CD14^＋＋CD16^＋ monocytes during chronic HCV infection and provides new insights into the specific role of the CD14^＋＋CD16^＋ monocytes and their significance in chronic HCV infection.

关键词： core antigen hepatitis C virus monocytes PD-L1/CD86 viral load

水性雾润纸张脱酸方法中的古书画字迹洇化扩散研究

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文物保护与考古科学 2024年第2期36卷 45-51页

作者：王思浓徐春辉金姗姗陈炳铨张红东施文正复旦大学图书馆中华古籍保护研究院上海200433 杭州众材科技股份有限公司浙江杭州310013 复旦大学高分子科学系上海200433

水溶液脱酸法是酸化纸张常用的脱酸方法,然而水相脱酸容易导致字迹,特别是水溶性字迹的洇化扩散(或称晕染、跑墨),这种现象一直是学术和行业研究的难点与痛点。本工作研究了纸张的浸润性质和字迹颜料的扩散性质,讨论了不同纸张、字迹颜... 详细信息

水溶液脱酸法是酸化纸张常用的脱酸方法,然而水相脱酸容易导致字迹,特别是水溶性字迹的洇化扩散(或称晕染、跑墨),这种现象一直是学术和行业研究的难点与痛点。本工作研究了纸张的浸润性质和字迹颜料的扩散性质,讨论了不同纸张、字迹颜料在脱酸过程中的防洇化安全性,提出了洇化临界加湿量的概念。研究表明洇化临界加湿量与字迹的溶解性、纸张浸润性直接相关:字迹的水溶性越好、纸张的浸润性越好(k值越大),则字迹越易洇化扩散、临界加湿量越小。雾润脱酸方法具有加湿量精确可调控、雾滴颗粒尺寸小且分布均匀的特点,能够根据纸张浸润性(k值)和字迹材料的溶解性,精确调控脱酸剂用量,使其低于洇化临界加湿量,进而避免字迹洇化现象的发生。研究结果为纸张文献的安全脱酸提供了可以选择的方法,为脱酸设备的开发和使用提供了科学依据。

关键词：脱酸字迹洇化雾润脱酸方法