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Friction 2024年第6期12卷 1283-1298页

作者： Junhyeon SEO Prahalada RAO Bart RAEYMAEKERS department of Mechanical Engineering Virginia TechBlacksburgVA 24061USA Grado department of Industrial and systems Engineering Virginia TechBlacksburgVA 24061USA

Numerically generating synthetic surface topography that closely resembles the features and characteristics of experimental surface topography measurements reduces the need to perform these intricate and costly ***,existing algorithms to numerically generated surface topography are not well-suited to create the specific characteristics and geometric features of as-built surfaces that result from laser powder bed fusion(LPBF),such as partially melted metal particles,porosity,laser scan lines,and ***,we present a method to generate synthetic as-built LPBF surface topography maps using a progressively growing generative adversarial *** qualitatively and quantitatively demonstrate good agreement between synthetic and experimental as-built LPBF surface topography maps using areal and deterministic surface topography parameters,radially averaged power spectral density,and material ratio *** ability to accurately generate synthetic as-built LPBF surface topography maps reduces the experimental burden of performing a large number of surface topography ***,it facilitates combining experimental measurements with synthetic surface topography maps to create large data-sets that facilitate,*** as-built surface topography to LPBF process parameters,or implementing digital surface twins to monitor complex end-use LPBF parts,amongst other applications.

关键词： additive manufacturing surface topography synthetic surface topography generative adversarial networks

Exact Box-Constrained Economic Operating Region for Power Grids Considering Renewable Energy Sources

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Journal of Modern Power systems and Clean Energy 2024年第2期12卷 514-523页

作者： Huating Xu Bin Feng Chutong Wang Chuangxin Guo Jian Qiu Mingyang Sun College of Electrical Engineering Zhejiang UniversityHangzhou 310027China department of control Science and Engineering Zhejiang UniversityHangzhou 310027China

The growing integration of renewable energy sources manifests as an effective strategy for reducing carbon emissions. This paper strives to efficiently approximate the set of optimal scheduling plans(OSPs) to enhance the performance of the steady-state adaptive cruise method(SACM) of power grid, improving the ability of dealing with operational uncertainties. Initially, we provide a mathematical definition of the exact boxconstrained economic operating region(EBC-EOR) for the power grid and its dispatchable components. Following this, we introduce an EBC-EOR formulation algorithm and the corresponding bi-level optimization models designed to explore the economic operating boundaries. In addition, we propose an enhanced big-M method to expedite the computation of the EBCEOR. Finally, the effectiveness of the EBC-EOR formulation, its economic attributes, correlation with the scheduling plan underpinned by model predictive control, and the significant improvement in computational efficiency(over twelvefold) are verified through case studies conducted on two test systems..

关键词： Exact box-constrained economic operating region(EBC-EOR) big-M method intelligent scheduling steady-state adaptive cruise uncertainty renewable energy source

Multi-carrier Tb/s silicon photonic coherent receiver

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Science China(Information Sciences) 2024年第1期67卷 284-291页

作者： Zhen WANG Xingfeng LI Jingchi LI Jian SHEN Yong ZHANG Yikai SU State Key Lab of Advanced Optical Communication systems and Networks Department of Electronic EngineeringShanghai Jiao Tong University

We propose a silicon polarization-diversity coherent receiver for wavelength-multiplexing transmission without using the large-footprint arrayed waveguide grating(AWG).We have integrated our proposed coherent receiver on the silicon-on-insulator(SOI) platform for high-capacity *** the proposed coherent receiver,high-frequency photocurrent signals from other wavelengths are suppressed by electrical low-pass ***,the signal-signal beat interference(SSBI) generated from each wavelength is eliminated by the balanced *** two features lend to the proposed coherent receiver being free of the mm-scale *** have demonstrated our proposed coherent receiver to detect a 1.12-Tb/s wavelength-division-multiplexed and polarization-division-multiplexed 16-ary quadrature amplitude modulation(PDM-16-QAM) *** compact footprint of the silicon chip promises small-form-factor receivers for future ultra-high-capacity coherent communication systems that require a high integration level and low fabrication cost.

关键词： silicon photonics optical receivers coherent communication wavelength-division-multiplexing(WDM) polarization-division-multiplexing(PDM)

LFM Radar Source Passive Localization Algorithm Based on Range Migration

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Journal of Beijing Institute of Technology 2024年第2期33卷 130-140页

作者： Dandan Li Deyi Wang Hao Huan Beijing Key Laboratory of Fractional Signals and systems School of Information and ElectronicsBeijing Institute of TechnologyBeijing 100081China Beijing Aerospace Automatic control Institute Beijing 100854China

Traditional single-satellite passive localization algorithms are influenced by frequency and angle measurement accuracies,resulting in error estimation of emitter position on the order of ***,a single-satellite localization algorithm based on passive synthetic aper-ture(PSA)was introduced,enabling high-precision ***,its estimation of azimuth and range distance is considerably affected by the residual frequency offset(RFO)of uncoopera-tive system ***,it requires data containing a satellite flying over the radia-tion source for RFO *** estimating the RFO,an accurate estimation of azimuth and range distance can be carried out,which is difficult to achieve in practical *** LFM radar source passive localization algorithm based on range migration is proposed to address the dif-ficulty in estimating frequency *** algorithm first provides a rough estimate of the pulse repetition time(PRT).It processes intercepted signals through range compression,range interpola-tion,and polynomial fitting to obtain range migration ***,it uses the changing information of range migration and an accurate PRT to formulate a system of nonlinear equations,obtaining the emitter position and a more accurate PRT through a two-step localization *** offset only induces a fixed offset in range migration,which does not affect the changing *** algorithm can also achieve high-precision localization in squint ***,the effectiveness of this algorithm is verified through simulations.

关键词： passive localization range migration residual frequency offset

An Online Q-Learning Method for Linear-Quadratic Nonzero-Sum Stochastic Differential Games with Completely Unknown Dynamics

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Journal of systems Science & Complexity 2024年第5期37卷 1907-1922页

作者： ZHANG Bao-Qiang WANG Bing-Chang CAO Ying School of control Science and Engineering Shandong University

In this paper, the authors design a reinforcement learning algorithm to solve the adaptive linear-quadratic stochastic n-players non-zero sum differential game with completely unknown dynamics. For each player, a critic network is used to estimate the Q-function, and an actor network is used to estimate the control input. A model-free online Q-learning algorithm is obtained for solving this kind of problems. It is proved that under some mild conditions the system state and weight estimation errors can be uniformly ultimately bounded. A simulation with five players is given to verify the effectiveness of the algorithm.

关键词： Actor-critic algorithm model-free adaptive control nonzero-sum stochastic game reinforcement learning

Value iteration algorithm for continuous-time linear quadratic stochastic optimal control problems

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Science China(Information Sciences) 2024年第2期67卷 170-180页

作者： Guangchen WANG Heng ZHANG School of control Science and Engineering Shandong University

In this study, we investigate a continuous-time infinite-horizon linear quadratic stochastic optimal control problem with multiplicative noise in control and state variables. Using the techniques of stochastic stability, exact observability, and stochastic approximation, a value iteration algorithm is developed to solve the corresponding generalized algebraic Riccati equation. Unlike the existing policy iteration algorithm, this algorithm does not rely on an initial stabilizing control. Further, this algorithm can also be used to compute policy evaluation steps that arise in the policy iteration algorithm. Herein, a simulation example is provided to validate the obtained results.

关键词： stochastic systems optimal control linear quadratic stochastic problem generalized algebraic Riccati equation value iteration algorithm

An Outbreak of Serogroup Y Meningococcal Meningitis in a Private Secondary Vocational School-Guangzhou City,Guangdong Province,China,2023

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China CDC weekly 2024年第12期6卷 242-246,I0005页

作者： Xiang Zeng Qing He Yilan Li Yong Zhou Xiaoping Shao Pei Hu Jian Liang Yudan Song Chao Ma Lijie Zhang Limei Sun Lei Luo Chinese Field Epidemiology Training Program Chinese Center for Disease Control and PreventionBeijingChina Zhuhai Center for Disease control and Prevention Zhuhai CityGuangdong ProvinceChina Guangdong Center for Disease control and Prevention Guangzhou CityGuangdong ProvinceChina Guangzhou Center for Disease control and Prevention Guangzhou CityGuangdong ProvinceChina Institute of Public Health Guangzhou Medical University&Guangzhou Center for Disease Control and PreventionGuangzhou CityGuangdong ProvinceChina department of the National Immunization Programme Chinese Center for Disease Control and PreventionBeijingChina

What is already known about this topic?The inclusion of meningococcal vaccines in the National Immunization Program(NIP)over several years has significantly reduced the incidence of meningococcal meningitis in China to historic ***,there has been a diversification of meningococcal serogroups,leading to a shift in dominant serogroups in China from serogroup A to serogroups C and B,accompanied by a rise in reports of serogroups Y and *** is added by this report?An outbreak of serogroup Y Neisseria meningitidis(Nm)in a secondary vocational school involved a single confirmed severe case and 24 individuals with laboratory-confirmed Nm *** investigation revealed that the outbreak was localized to the classroom of the confirmed *** close contact within a confined space was identified as a significant risk factor for Nm *** genotype sequence identified was type 1655(ST-1655),which is categorized under clonal complex 23(CC-23)and bears resemblance to 8 previously confirmed cases of serogroup Y meningococcal meningitis within Guangdong *** suggests that serogroup Y infections continue to sporadically emerge and have become prevalent *** are the implications for public health practice?This outbreak underscores the critical need to enhance surveillance of meningococcal serogroups and population carrier,and advocate for vaccination with MenY-containing vaccines.

关键词： break Secondary Guangdong

A Scholar of Dignity:Remembering Peter Luh

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IEEE/CAA Journal of Automatica Sinica 2024年第9期11卷 1895-1897页

作者： Fei-Yue Wang Macao University of Science and Technology Macao 999078China Beijing Engineering Research Center of Intelligent systems and Technology Chinese Academy of SciencesBeijing 100190China State Key Laboratory for Management and control of Complex systems Chinese Academy of SciencesBeijing 100190China

It was a shock and disbelief to learn of Peter's death last *** me,he was so fit in his figure,so healthy in his lifestyle,so mild and mindful in his social behavior,and so devout in his religious belief,......,I had ... 详细信息

关键词： religious Scholar belief

Global adaptive output-feedback tracking with prescribed performance for uncertain nonlinear systems

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Science China(Information Sciences) 2024年第5期67卷 150-164页

作者： Yuan WANG Yungang LIU School of control Science and Engineering Shandong University

At present, one typical control strategy for guaranteeing transient and steady-state performance is funnel control and prescribed performance control. The strategy features completely discarding the system nonlinearities, even if they are completely known and available. Such an intrinsic feature requires the controller to produce a larger control effect to eliminate the negative impact caused by the high nonlinearities, leading to a conservative controller. In this paper, we fully take advantage of known information on nonlinearities in control design, instead of completely discarding it as done in funnel control. Particularly, we leverage adaptive techniques(i.e., high-gain dynamic compensation) to deal with unknown system nonlinearities. Meanwhile, we integrate the tools of output feedback, tracking control, and the performance *** such, an adaptive output-feedback scheme is developed for global tracking with spatiotemporal performance specifications: arbitrarily given tracking accuracy and accuracy-ensured time. A simulation example supports the developed approach.

关键词： uncertain nonlinear systems output feedback prescribed performance unknown control direction dynamic high gain global tracking

Object Helps U-Net Based Change Detectors

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 548-550页

作者： Lan Yan Qiang Li Kenli Li College of Computer Science and Electronic Engineering Hunan UniversityChangsha 410082China State Key Laboratory for Management and control of Complex systems Institute of AutomationChinese Academy of SciencesBeijing 100190China

Dear Editor,This letter focuses on leveraging the object information in images to improve the performance of the U-Net based change *** detection is fundamental to many computer vision *** existing solutions based on ... 详细信息

关键词： Net computer networks