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Model-free method for LQ mean-field social control problems with one-dimensional state space

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Control Theory and Technology 2024年第3期22卷 479-486页

作者： Zhenhui xu Tielong shen School of Engineering Tokyo Institute of TechnologyTokyo 152-8550Japan Department of Engineering and Applied Sciences Sophia UniversityTokyo 102-8554Japan

This paper presents a novel model-free method to solve linear quadratic(LQ)mean-field control problems with one-dimensional state space and multiplicative *** focus is on the infinite horizon LQ setting,where the conditions for solution either stabilization or optimization can be formulated as two algebraic Riccati equations(AREs).The proposed approach leverages the integral reinforcement learning technique to iteratively solve the drift-coefficient-dependent stochastic ARE(SARE)and other indefinite ARE,without requiring knowledge of the system dynamics.A numerical example is given to demonstrate the effectiveness of the proposed algorithm.

关键词： Mean-field control Social optima Infinite horizon Reinforcement learning

Feedback of Efficient Shock Acceleration on Magnetic-field Structure Inside Young Type Ia Supernova Remnants

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Research in Astronomy and Astrophysics 2024年第6期24卷 234-244页

作者： Jun-Yu shen Bi-Wen bao Li Zhang Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan UniversityKunming 650091China Key Laboratory of Statistical Modeling and Data Analysis of Yunnan Province Yunnan UniversityKunming 650091China

Using an effective adiabatic index γ_(eff) to mimic the feedback of efficient shock acceleration,we simulate the temporal evolution of a young type Ia supernova remnant (SNR) with two different background magnetic field(BMF) topologies:a uniform and a turbulent *** density distribution and magnetic-field characteristics of our benchmark SNR are studied with two-dimensional cylindrical magnetohydrodynamic *** γ_(eff)is considered,we find that:(1) the two-shock structure shrinks and the downstream magnetic-field orientation is dominated by the Rayleigh–Taylor instability structures;(2) there exists more quasi-radial magnetic fields inside the shocked region;and (3) inside the intershock region,both the quasi-radial magnetic energy density and the total magnetic energy density are enhanced:in the radial direction,with γ_(eff)=1.1,they are amplified about 10–26 times more than those with γ_(eff)=5/*** in the angular direction,the total magnetic energy densities could be amplified about 350 times more than those with γ_(eff)=5/3,and there are more grid cells within the intershock region where the magnetic energy density is amplified by a factor greater than 100.

关键词： methods:numerical ISM:magnetic fields ISM:supernova remnants magnetohydrodynamics(MHD)

Bioinspired 3D flexible devices and functional systems

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National Science Review 2024年第3期11卷 271-295页

作者： xu Cheng Zhangming shen Yihui Zhang Applied Mechanics Laboratory Department of Engineering Mechanics Tsinghua University Laboratory of Flexible Electronics Technology Tsinghua University

Flexible devices and functional systems with elaborated three-dimensional(3D) architectures can endow better mechanical/electrical performances, more design freedom, and unique functionalities, when compared to their two-dimensional(2D) counterparts. Such 3D flexible devices/systems are rapidly evolving in three primary directions, including the miniaturization, the increasingly merged physical/artificial intelligence and the enhanced adaptability and capabilities of heterogeneous *** challenges exist in this emerging research area, such as relatively poor controllability in the locomotion of soft robotic systems, mismatch of bioelectronic interfaces, and signal coupling in multi-parameter sensing. By virtue of long-time–optimized materials, structures and processes, natural organisms provide rich sources of inspiration to address these challenges, enabling the design and manufacture of many bioinspired 3D flexible devices/systems. In this Review, we focus on bioinspired 3D flexible devices and functional systems, and summarize their representative design concepts, manufacturing methods, principles of structure-function relationship and broad-ranging applications. Discussions on existing challenges, potential solutions and future opportunities are also provided to usher in further research efforts toward realizing bioinspired 3D flexible devices/systems with precisely programmed shapes,enhanced mechanical/electrical performances, and high-level physical/artificial intelligence.

关键词： bioinspired designs biomimetic 3D structures 3D flexible electronics 3D functional systems direct 3D manufacture 2D-to-3D assembly

Barrier Option Pricing in Regime Switching Models with Rebates

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 849-861页

作者： Yue-xu ZHAO Jia-yong bao School of Economics Hangzhou Dianzi UniversityHangzhou 310018China School of Sciences Hangzhou Dianzi UniversityHangzhou 310018China

This paper is concerned with the valuation of single and double barrier knock-out call options in a Markovian regime switching model with specific *** integral formulas of the rebates are derived via matrix Wiener-Hopf factorizations and Fourier transform techniques,also,the integral representations of the option prices are ***,the first-passage time density functions in two-state regime model are *** applications,several numerical algorithms and numerical examples are presented.

关键词： option pricing Markovian regime switching Wiener-Hopf factorization Fourier transform

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Effects of the mineral phase and valence of vanadium on vanadium extraction from stone coal

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International Journal of Minerals,Metallurgy and Materials 2012年第10期19卷 893-898页

作者： Yang-jia Hu Yi-min Zhang shen-xu bao Tao Liu College of Resources and Environmental Engineering Wuhan University of Technology Wuhan 430070 China Hubei Key Laboratory of Mineral Resources Processing and Environment Wuhan 430070 China

The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when the raw ore is leached by 4 moUL H2SO4 at 90℃ for 2 h. After the sample is roasted at 900℃ for 2 h, the leaching rate of vanadium reaches the maximum, and more than 70% of vanadium can be leached. The crystal of vanadium-bearing mica minerals decomposes and the Content of V（V） increases with the rise of roasting temperature from 600 to 900℃, therefore the leaching rate of vanadium increases significantly with the decomposition of the mica minerals. Some new phases, anorthite for example, form when the roasting temperature reaches 1000℃. A part of vanadium may be enwrapped in the sintered materials and newly formed phases, which may impede the oxidation of low valent vanadium and make the leaching rate of vanadium drop dramatically. The leaching rate of vanadium is not only determined by the valence state of vanadium but also controlled by the decomposition of vanadium-bearing minerals and the existence state of vanadium to a large extent.

关键词： vanadium metallurgy stone coal leaching ore roasting

Multi-level coarse-grained discrete element method modeling of cylinder particle flow in a rotating drum

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Particuology 2024年第5期88卷 218-238页

作者： Lei xu Xiukai Wu Shuai Wang Shiyi bao Institute of Process Equipment and Control Engineering Zhejiang University of TechnologyHangzhou 310023China Engineering Research Center of Process Equipment and Remanufacturing Ministry of EducationZhejiang University of TechnologyHangzhou 310023China College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China

The coarse-grained discrete element method(DEM)is probably a feasible option for simulating an actual drum-type biomass boiler,which contains over 10 million cylinder particles.A multi-level study was conducted based on particle and coarse-grained level data to evaluate the adequacy of the coarse-grained approach in terms of geometrical characteristics,kinematic features,and dynamic *** scaling laws for contact parameters were used and compared during the *** results show that the coarse-grained approach can accurately predict the positions of the free surface and active-passive interface,the mixing index,and the orientation *** in the velocity fields may occur due to the worse flowability of coarse-grained particles near the free *** efficiency is significantly improved by the coarse-grained model compared with the corresponding original case(the same DEM code without a coarse-grained model was used for the original simulations).

关键词： Coarse-grained method Discrete element method(DEM) Cylinder particle Rotating drum Granular flow

Hybrid tri-memristor hyperchaotic map and application in Wasserstein Generative Adversarial Nets

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Science China(Technological Sciences) 2024年第6期67卷 1855-1865页

作者： GU Yang bao Han YU XiHong HUA ZhongYun bao BoCheng xu Quan School of Microelectronics and Control Engineering Changzhou UniversityChangzhou213159China School of Computer Science and Technology Harbin Institute of TechnologyShenzhen518055China

Inspired by basic circuit connection methods,memristors can also be utilized in the construction of complex discrete chaotic *** investigate the dynamical effects of hybrid memristors,we propose two hybrid tri-memristor hyperchaotic(HTMH)mapping structures based on the hybrid parallel/cascade and cascade/parallel operations,*** the HTMH mapping structure with hybrid parallel/cascade operation as an example,this map possesses a spatial invariant set whose stability is closely related to the initial states of the *** distributions and bifurcation behaviours dependent on the control parameters are explored with numerical ***,the memristor initial offset-boosting mechanism is theoretically demonstrated,and memristor initial offset-boosting behaviours are numerically *** results clarify that the HTMH map can exhibit hyperchaotic behaviours and extreme multistability with homogeneous coexisting infinite *** addition,an FPGA hardware platform is fabricated to implement the HTMH map and generate pseudorandom numbers(PRNs)with high ***,the generated PRNs can be applied in Wasserstein generative adversarial nets(WGANs)to enhance training stability and generation capability.

关键词： memristor hybrid tri-memristor map spatial invariant set hyperchaos extreme multistability generative adversarial nets

Towards the performance limit of catenary meta-optics via field-driven optimization

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Opto-Electronic Advances 2024年第5期7卷 33-42页

作者： Siran Chen Yingli Ha Fei Zhang Mingbo Pu Hanlin bao Mingfeng xu Yinghui Guo Yue shen Xiaoliang Ma Xiong Li Xiangang Luo National Key Laboratory of Optical Field Manipulation Science and Technology Chinese Academy of SciencesChengdu 610209China State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering Institute of Optics and ElectronicsChinese Academy of SciencesChengdu 610209China College of Materials Science and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China Research Center on Vector Optical Fields Institute of Optics and ElectronicsChinese Academy of SciencesChengdu 610209China Department of Electrical and Computer Engineering University of California Los Angeles(UCLA)Los AngelesCalifornia 90095USA

Catenary optics enables metasurfaces with higher efficiency and wider bandwidth,and is highly anticipated in the imaging system,super-resolution lithography,and broadband ***,the periodic boundary approximation without considering aperiodic electromagnetic crosstalk poses challenges for catenary optical devices to reach their performance ***,perfect control of both local geometric and propagation phases is realized through field-driven optimization,in which the field distribution is calculated under real boundary *** from other optimization methods requiring a mass of iterations,the proposed design method requires less than ten iterations to get the efficiency close to the optimal *** on the library of shape-optimized catenary structures,centimeter-scale devices can be designed in ten seconds,with the performance improved by ~15%.Furthermore,this method has the ability to extend catenary-like continuous structures to arbitrary polarization,including both linear and elliptical polarizations,which is difficult to achieve with traditional design *** provides a way for the development of catenary optics and serves as a potent tool for constructing high-performance optical devices.

关键词： catenary optics catenary structures field-driven optimization

Improving the accuracy of precipitation estimates in a typical inland arid area of China using a dynamic Bayesian model averaging approach

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Journal of Arid Land 2024年第3期16卷 331-354页

作者： xu Wenjie DING Jianli bao Qingling WANG Jinjie xu Kun College of Geography and Remote Sensing Sciences Xinjiang UniversityUrumqi 830017China Key Laboratory of Smart City and Environment Modelling of Higher Education Institute Xinjiang UniversityUrumqi 830017China

Xinjiang Uygur Autonomous Region is a typical inland arid area in China with a sparse and uneven distribution of meteorological stations,limited access to precipitation data,and significant water *** and integrating precipitation datasets from different sources to accurately characterize precipitation patterns has become a challenge to provide more accurate and alternative precipitation information for the region,which can even improve the performance of hydrological *** study evaluated the applicability of widely used five satellite-based precipitation products(Climate Hazards Group InfraRed Precipitation with Station(CHIRPS),China Meteorological Forcing Dataset(CMFD),Climate Prediction Center morphing method(CMORPH),Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record(PERSIANN-CDR),and Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis(TMPA))and a reanalysis precipitation dataset(ECMWF Reanalysis v5-Land Dataset(ERA5-Land))in Xinjiang using ground-based observational precipitation data from a limited number of meteorological *** on this assessment,we proposed a framework that integrated different precipitation datasets with varying spatial resolutions using a dynamic Bayesian model averaging(DBMA)approach,the expectation-maximization method,and the ordinary Kriging interpolation *** daily precipitation data merged using the DBMA approach exhibited distinct spatiotemporal variability,with an outstanding performance,as indicated by low root mean square error(RMSE=1.40 mm/d)and high Person's correlation coefficient(CC=0.67).Compared with the traditional simple model averaging(SMA)and individual product data,although the DBMA-fused precipitation data were slightly lower than the best precipitation product(CMFD),the overall performance of DBMA was more *** error analysis between DBMA-fused precipitation dataset and the more advanced Inte

关键词： precipitation estimates satellite-based and reanalysis precipitation dynamic Bayesian model averaging streamflow simulation Ebinur Lake Basin Xinjiang