检索结果-南通市图书馆

Journal of Systems Science & Complexity 2023年第3期36卷 909-921页

作者： su Hang cheng Bin LI Zhongkui State Key Laboratory for Turbulence and Complex Systems and Department of Mechanics and Engineering Science College of EngineeringPeking UniversityBeijing 100871China Department of Control Science and Engineering College of Electronics and Information EngineeringTongji UniversityShanghai 201804China Frontiers Science Center for Intelligent Autonomous Systems Shanghai 201210China

This paper investigates the cooperative output regulation problem of heterogeneous linear multi-agent systems over directed graphs with the constraint of communication bandwidth.Given that there exists an exosystem whose state information is not available to all agents,the authors develop distributed adaptive event-triggered observers for the followers based on relative information between neighboring agents.It should be pointed out that,two kinds of time-varying gains are introduced to avoid relying on any global information associated with the network,and dynamic triggering conditions are designed to get rid of continuous communications.On the basis of the designed observers,the authors devise a local controller for each agent.Compared with the existing related works,the main contribution of the current paper is that the cooperative output regulation problem for general directed graphs is solved requiring neither global information nor continuous communications.

关键词： Adaptive control consensus cooperative output regulation directed graph event-triggered control multi-agent systems

Epidemiological Study of Outpatients in Rabies Post-Exposure Prophylaxis Clinics—Tianjin Municipality,China,2020

在线全文

学校读者我要写书评

暂无评论

China CDC weekly 2021年第39期3卷 822-824页

作者： Yifang Liu Lin Li Jie Lyu Cheng Su Tianjin Centers for Disease Control and Prevention TianjinChina.

summary What is already known on this topic?Rabies remains a serious public health problem in China.The only way to prevent the fatal disease was through timely and adequate post-exposure prophylaxis(PEP).What is added by this report?Among all the 126,133 cases visited Tianjin PEP clinics during 2020,more than 90%of the patients were injured by domestic dogs or cats,and about 70%of the animals received vaccination.Most outpatients have knowledge of rabies and show high compatibility with PEP.

关键词： Tianjin compatibility Rabies

非一致地震激励下大跨度桥梁弹塑性随机响应分析研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

振动与冲击 2021年第12期40卷 297-304,310页

作者：刘小璐苏成聂铭广东电网有限责任公司电力科学研究院广州510080 华南理工大学土木与交通学院广州510640

大跨度桥梁地震激励具有明显的非一致性和随机性,且在强震作用下大桥部分构件会进入弹塑性状态,然而目前尚缺乏非一致地震激励下大跨度桥梁弹塑性随机响应的有效计算方法。在大质量法的基础上推导了非一致地震激励下大跨度桥梁弹塑性动... 详细信息

大跨度桥梁地震激励具有明显的非一致性和随机性,且在强震作用下大桥部分构件会进入弹塑性状态,然而目前尚缺乏非一致地震激励下大跨度桥梁弹塑性随机响应的有效计算方法。在大质量法的基础上推导了非一致地震激励下大跨度桥梁弹塑性动力响应的时域显式表达式,利用该表达式的降维列式优势,仅需针对结构弹塑性单元自由度进行迭代计算,进而对大跨度桥梁结构快速开展弹塑性时程分析;结合蒙特卡罗法,高效获取非一致地震激励下大跨度桥梁的弹塑性随机响应。以某主跨为1200 m的悬索桥为工程实例,采用纤维梁柱单元模拟大桥弹塑性构件,开展顺桥向非一致地震激励下的弹塑性时程分析以及弹塑性随机振动分析,验证了该方法的正确性和高效性。研究结果表明,该大桥非一致地震激励下的内力标准差和平均峰值比一致地震激励下的结果既可能偏大也可能偏小。

关键词：大跨度桥梁随机振动非一致地震激励弹塑性降维迭代

Changes in cesarean section rates and its indications among primiparous women during each implementation phase of Chinese two-child policy:a retrospective study

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2022年第18期135卷 2264-2266页

作者： Yumei cheng Shaofei su Shaowen Wu Department of Perinatal Medicine Beijing Obstetrics and Gynecology HospitalCapital Medical UniversityBeijing Maternal and Child Health Care HospitalBeijing 100026China Department of Central Laboratory Beijing Obstetrics and Gynecology HospitalCapital Medical UniversityBeijing Maternal and Child Health Care HospitalBeijing 100026China

To the Editor:Cesarean section(CS)is among the most important and safe procedures in obstetrics.When medically indicated,CS can be a life-saving intervention.During the Chinese one-child policy,couples tended to choose CS for various reasons.In 2010,the CS rate in China rose to among the world’s highest.^([1])Yet,CS can also have various adverse maternal and neonatal consequences.Maternal mortality and maternal and infant complications are higher with CS compared with vaginal delivery.[2]Over the past several decades,CS rates have increased sharply worldwide,and controlling these rates has become among the most prominent obstetric issues.

关键词： section policy among

Fundamental Limits of Doppler Shift-Based, ToA-Based,and TDoA-Based Underwater Localization

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2023年第7期10卷 1637-1639页

作者： Zijun Gong cheng Li Ruoyu su Hong Kong University of Science and Technology(Guangzhou) IOT ThrustGuangzhou 511400 Department of Electronic and Computer Engineering The Hong Kong University of Science and TechnologyHong Kong 999077China Faculty of Engineering and Applied Science Memorial University of NewfoundlandNewfoundland A1B 3X5Canada School of Internet of Things Nanjing University of Posts and TelecommunicationsNanjing 210003China

Dear Editor,This paper is concerned with the underwater localization based on acoustic signals. Specifically, we will focus on the search of an underwater target that can constantly broadcast a beacon signal, such as a black box. Common measurements for localization are Doppler shift [1], time of arrival(ToA) [2]–[4], time difference of arrival(TDoA) [5], [6], angle of arrival(AoA) [7], etc.

关键词： TDoA ToA underwater

Establishment of a metric to characterize retroreflector properties using a consumer-grade colour camera

在线全文

学校读者我要写书评

暂无评论

Transportation Safety and Environment 2023年第1期5卷 31-40页

作者： Huayang He Wenying su Qiutong cheng National Center of Metrization for Equipments of Roads and Bridges Research Institute of Highway Ministry of TransportBeijing 100088China Division of Optical Metrology National Institute of MetrologyBeijing 100029China

The coefficients of retroreflection and chromaticity coordinates are critical metrics for determining the quality of a retroreflector.However,conventional retroreflection measurement techniques rely heavily on the night-time colour,size and characteristics of thesample being measured.This complicates the measurement process and leads to deviations in the test results.In addition,chromaticitycannot be determined using this approach.Therefore,it is necessary to improve the measurement accuracy,simplify themeasurement process and achieve themeasurement of the traffic sign RA and chromaticity coordinates simultaneously.In this study,an improved method for retroreflector characterization using imaging was proposed.This allowed for the measurement of the coefficientsof retroreflection and the chromaticity coordinates simultaneously,and only a white standard sample was required for calibration.The primary components of the proposed system included a lighting projector,a receiver,two motorized rotational stages,a retroreflective sample holder and customized software that using scaling factors to convert a digital signal into sample retroreflectioncoefficients and retroreflective chromaticity coordinates.The experimental results indicated that the raw data output from thecamera exhibited a positive correlation relationship with the luminous flux from the surface of the retroreflector.The maximummeasurementerrors for the retroreflection and chromaticity were−12.2 cd/(lx·m2)and−2.09%,respectively.Thismethod was inexpensiveand convenient,used a commercially available digital camera,could help to identify defects in retroreflection and chromaticity forretroreflective sheeting and led to increased accessibility for the quality control of retroreflective sheeting.

关键词： camera chromaticity coordinates coefficient of retroreflection retroreflective sheeting retroreflector

Synthesis and characterization of a novel collector for the desulfurization of fine high-sulfur bauxite via reverse flotation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2023年第8期79卷 64-77页

作者： Gan cheng Jianqiang Zhang Huanhuan su Zhanyun Zhang Zhengzhou Non-ferrous Metals Research Institute Co.Ltd. Aluminum Corporation of ChinaZhengzhou450041China College of Chemistry and Chemical Engineering Henan Polytechnic UniversityJiaozuo454000China Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization Henan Polytechnic UniversityJiaozuo454000China

Bauxite is one of the main raw materials in the alumina industry.Fine high-sulfur bauxite flotation desulfurization is a great challenge presently.This study aims to synthesize nanoparticle collectors(NPCs)by emulsion polymerization to improve the abovesaid flotation desulfurization process.The physicochemical properties of high-sulfur bauxite were analyzed,and the experimental conditions for the synthesis of NPCs were optimized.The interaction mechanism between NPCs and pyrite was studied via fundamental analyses including SEM(Scanning Electron Microscope),FT-IR(Fourier Transform Infrared spectoscopy),Zeta-potential,XPS(X-ray Photoelectron Spectroscopy),and wettability.Under the closed-circuit flotation flowsheet of"one roughing-two cleaning-three scavenging",aluminum concen-trate with a yield of 85.91%and sulfur content of 0.56%were obtained using a common collector.However,with the addition of the novel NPC,aluminum concentrate with a yield of 85.70%and sulfur content of 0.36%could be obtained by a simpler flowsheet of"one roughing-one cleaning-two scav-enging".The improvement in flotation performance is suggested to be contributed by the addition of spherical NPC,which induced a rougher and more hydrophobic pyrite surface.

关键词： Bauxite Flotation desulfurization Nanoparticle collector Pyrite

Static workspace analysis of a multi-robot collaborative towing system with floating base

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Modeling, Simulation, and Scientific Computing 2021年第2期12卷 66-79页

作者： Cheng Su Jinghang Li Wangcai Ding Zhigang Zhao School of Mechatronic Engineering Lanzhou Jiaotong University Lanzhou Gansu730070P.R.China

The static workspace of the multi-robot collaborative towing system with floating base was analyzed.The spacial configuration of the system was built,and the system was divided into three types according to the actuation.The kinematic and dynamic models of the floating base and the towing system were established,respectively,by using the Newton-Euler equation.Then the static workspace of the system was analyzed,and the specific steps to solve the workspace with the improved Monte Carlo method were obtained.Finally,the static workspaces of three types of systems were solved though actual simulation calculation,the simulation results show that the improved Monte Carlo method can get a workspace with higher precision compare to the traditional Monte Carlo method.Results of this study lay a basis for the subsequent trajectory plan,stability analysis and configuration optimization of the system.

关键词： Multi-robot cable-driven Monte Carlo method workspace simulation

Adaptive time-space resource and waveform control for collocated MIMO radar with simultaneous multi-beam

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2022年第1期33卷 47-59页

作者： cheng Ting LI Xi TAN Qianqian su Yang School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

Collocated multiple input multiple output(MIMO)radar,which has agile multi-beam working mode,can offer enhanced multiple targets tracking(MTT)ability.In detail,it can illuminate different targets simultaneously with multi-beam or one wide beam among multi-beam,providing greater degree of freedom in system resource control.An adaptive time-space resource and waveform control optimization model for the collocated MIMO radar with simultaneous multi-beam is proposed in this paper.The aim of the proposed scheme is to improve the overall tracking accuracy and meanwhile minimize the resource consumption under the guarantee of effective targets detection.A resource and waveform control algorithm which integrates the genetic algorithm(GA)is proposed to solve the optimization problem.The optimal transmitting waveform parameters,system sampling period,sub-array number,binary radar tracking parameterχ_i(t_k),transmitting energy and multi-beam direction vector combination are chosen adaptively,where the first one realizes the waveform control and the latter five realize the timespace resource allocation.Simulation results demonstrate the effectiveness of the proposed control method.

关键词： multiple targets tracking(MTT) collocated multiple input multiple output(MIMO)radar time-space resource allocation waveform control

Stochastic transient analysis of thermal stresses in solids by explicit time-domain method

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2019年第5期9卷 293-296,I0004页

作者： Houzuo Guo Cheng Su Jianhua Xian School of Civil Engineering and Transportation South China University of TechnologyGuangzhou 510640China State Key Laboratory of subtropical Building Science South China University of TechnologyGuangzhou 510640China

Stochastic heat conduction and thermal stress analysis of structures has received considerable attention in recent years.The propagation of uncertain thermal environments will lead to stochastic variations in temperature fields and thermal stresses.Therefore,it is reasonable to consider the variability of thermal environments while conducting thermal analysis.However,for ambient thermal excitations,only stationary random processes have been investigated thus far.In this study,the highly efficient explicit time-domain method(ETDM)is proposed for the analysis of non-stationary stochastic transient heat conduction and thermal stress problems.The explicit time-domain expressions of thermal responses are first constructed for a thermoelastic body.Then the statistical moments of thermal displacements and stresses can be directly obtained based on the explicit expressions of thermal responses.A numerical example involving non-stationary stochastic internal heat generation rate is investigated.The accuracy and efficiency of the proposed method are validated by comparison with the Monte-Carlo simulation.

关键词： Stochastic Non-stationary Heat conduction Thermal stress Explicit time-domain method