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Mission scheduling of multi-sensor collaborative observation for space surveillance network

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Journal of Systems Engineering and Electronics 2023年第4期34卷 906-923页

作者： LONG Xi cai weiwei YANG Leping WANG Tianyu College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China School of Traffic and Transportation Engineering Central South UniversityChangsha 410073China

With increased dependence on space assets,scheduling and tasking of the space surveillance network(SSN)are vitally important.The multi-sensor collaborative observation scheduling(MCOS)problem is a multi-constraint and high-conflict complex combinatorial optimization problem that is nondeterministic polynomial(NP)-hard.This research establishes a sub-time window constraint satisfaction problem(STWCSP)model with the objective of maximizing observation profit.Considering the significant effect of genetic algorithms(GA)on solving the problem of resource allocation,an evolution heuristic(EH)algorithm containing three strategies that focus on the MCOS problem is proposed.For each case,a task scheduling sequence is first obtained via an improved GA with penalty(GAPE)algorithm,and then a mission planning algorithm(heuristic rule)is used to determine the specific observation time.Compared to the model without sub-time windows and some other algorithms,a series of experiments illustrate the STWCSP model has better performance in terms of total profit.Experiments about strategy and parameter sensitivity validate its excellent performance in terms of EH algorithms.

关键词： multi-sensor observation resource scheduling subtime window evolution heuristic algorithm

Development of a single-camera volumetric thermometry for gas flows based on space division multiplexing

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Science China(Technological Sciences) 2022年第7期65卷 1646-1650页

作者： WANG Qian LIU HeCong cai weiwei Key Laboratory of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Optical imaging methods have been widely applied in combustion diagnostics due to their high sensitivity, versatility, non-intrusiveness, and amenability for implementation in harsh environment [1,2]. Compared with traditional intrusive diagnostics, such as thermometry with thermocouples and manometry with pressure transducers, planar imaging methods provide richer insights into fluid dynamics and complex combustion phenomena.

关键词： planar insight flows

Benchmark evaluation of tomographic algorithms for simultaneous reconstruction of temperature and volume fraction fields of soot and metal-oxide nanoparticles in non-uniform flames

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Science China(Technological Sciences) 2021年第2期64卷 237-250页

作者： SHUI ChongYuan LIU HeCong cai weiwei Key Laboratory for Power Machinery and Engineering of Ministry of Education School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

With the growing applications of nanofluid flame, the monitoring and controlling of its combustion process is of paramount importance. Thus, it is necessary to develop diagnosing methods which can simultaneously image important parameters such as temperature and volume fractions of soot, metal-oxide nanoparticles. Tomographic emission spectroscopy is an effective method which has been proposed for this purpose. However, the inversion process was only reported with least-squares QR decomposition(LSQR) so far and there are numerous well-established reconstruction algorithms which have not been utilized yet.Thus, this work aims to perform systematic comparative studies on several representative algorithms for the inversion process. In the simulative studies, algorithms including Tikhonov regularization, algebraic reconstruction technique(ART), LSQR,Landweber algorithm, maximum likelihood expectation maximization(MLEM), and ordered subset expectation maximization(OSEM) were discussed. The effects of the number of iterations, the signal-to-noise ratio, and the number of projections and the calibration error in projection angles on the performance of the algorithms were investigated. Advice on selecting the suitable algorithms under different application conditions is then provided according to the extensive numerical studies.

关键词： inverse analysis algorithms temperature field soot and metal-oxide volume fraction non-uniform nanofluid flame

Volumetric imaging of flame refractive index, density, and temperature using background-oriented Schlieren tomography

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Science China(Technological Sciences) 2021年第1期64卷 98-110页

作者： LIU HeCong HUANG JianQing LI Lei cai weiwei School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Volumetric imaging represents one of the major development trends of flow diagnostics due to both the advancement in hardware and the requirement for more information to further understand complicated turbulent and/or reactive flows. Backgroundoriented Schlieren tomography(BOST) has become increasingly popular due to its experimental simplicity. It has been demonstrated to be capable of simultaneously recovering the distributions of refractive index, density, and temperature of flows.However, its capability in thermometry has only been demonstrated under the axisymmetric assumption, which greatly limits its applicability. In this work, we dedicated to developing a cost-effective BOST system for the simultaneous retrieval of refractive index, density, and temperature distributions for the asymmetric flame. A few representative tomographic inversion algorithms were assessed as well. Both numerical and experimental demonstrations were conducted and the results show that our implemented BOST can successfully reconstruct the three-dimensional temperature distribution with a satisfactory accuracy.

关键词： Schlieren tomography combustion diagnostics temperature

Li-ion battery temperature estimation based on recurrent neural networks

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Science China(Technological Sciences) 2021年第6期64卷 1335-1344页

作者： JIANG YuHeng YU YiFei HUANG JianQing cai weiwei MARCO James Key Laboratory of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China University of Warwick-Warwick Manufacturing Group(WMG) Coventry CV47ALUK

The monitoring of Li-ion battery temperatures is essential to ensure high efficiency and safety.In this work,two types of recurrent neural networks (RNNs),which are long short-term memory-RNN (LSTM-RNN) and gated recurrent unit-RNN(GRU-RNN),are proposed to estimate the surface temperature of 18650 Li-ion batteries during the discharging processes under different ambient temperatures.The datasets acquired from the Prognostics Center of Excellence (PCo E) of NASA are used to train,validate and test the networks.In previous work,temperature has been set as the output of the networks;however,here the temperature difference along the time axis is adopted as the output.The net heat generated results in net temperature change,which is more closely aligned with electrochemical and thermodynamic laws.Extensive simulation results show that the two RNNs can achieve accurate real-time battery temperature estimation.The maximum absolute error in temperature estimation is approximately 0.75°C and the correlation coefficient between the estimated and measured temperature curves is greater than 0.95.The influences of three crucial parameters,which are the number of hidden neurons,initial learning rate and maximum number of iterations,are also assessed in terms of training time,root mean square error and mean absolute error.

关键词： battery temperature estimation model recurrent neural network long short-term memory gated recurrent unit

Formation keeping control through inter-satellite electromagnetic force

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Science China(Technological Sciences) 2013年第5期56卷 1102-1111页

作者： cai weiwei YANG LePing ZHU YanWei ZHANG YuanWen College of Aerospace Science and Engineering National University of Defense Technology

Satellite formation keeping through inter-satellite electromagnetic force provides an attractive alternative for future space missions due to its distinct advantages of no propellant consumption or plume contamination as compared to conventional approaches.However,the internal force nature as well as the high nonlinearity and coupling of electromagnetic force brings new control challenges for this novel technique.In this paper,analysis on the dynamics characteristics and special control issues in the presence of electromagnetic force is carried out on the basis of the derived relatively translational dynamics.Considering the model uncertainties,external disturbances and sensor noise,a combined nonlinear control scheme involving feed-forward and feedback control components is proposed for electromagnetic-force-based formation keeping.The feed-forward component is directly obtained through desired configuration and dynamics under nominal conditions while the feedback component is realized utilizing active disturbance rejection control methodology with some reasonable improvement.Numerical simulation is presented to verify the feasibility and validity of the combined control scheme.

关键词：耦合控制队形保持电磁力卫星间反馈元件卫星编队太空任务羽流污染

儿童感染新型冠状病毒后第3周行日间手术的可行性

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中华麻醉学杂志 2024年第1期44卷 31-35页

作者：宋玉婷蔡巍维顾伟仲山南京医科大学附属儿童医院麻醉科南京210000 南京医科大学附属儿童医院医务处南京210000

目的回顾性分析儿童感染新型冠状病毒后第3周行日间手术的可行性。方法收集2022年11月1日至2023年2月28日行日间手术患儿的临床资料,手术时间≤1 h,ASA分级Ⅰ或Ⅱ级,性别不限,年龄≤14岁,BMI 10~30 kg/m^(2)。根据是否感染过新型冠状病... 详细信息

目的回顾性分析儿童感染新型冠状病毒后第3周行日间手术的可行性。方法收集2022年11月1日至2023年2月28日行日间手术患儿的临床资料,手术时间≤1 h,ASA分级Ⅰ或Ⅱ级,性别不限,年龄≤14岁,BMI 10~30 kg/m^(2)。根据是否感染过新型冠状病毒将患儿分为新冠组和对照组,主要结局指标为患儿术后30 d内呼吸系统相关并发症发生率。次要结局指标包括患儿术后30 d内非计划通气、延迟出院和二次入院率,患儿术前肌酸激酶同工酶(CK-MB)、AST、ALT、Hb、白细胞计数、CRP水平、口咽黏膜炎症分级、手术时间、苏醒时间、术中呼吸抑制、喉痉挛、低氧血症、低血压、窦性心动过缓发生率和追加抢救药物率。结果新冠组337例,对照组1396例。与对照组比较,新冠组患儿术前CK-MB浓度升高,Hb浓度降低(P0.05)。结论儿童在感染新型冠状病毒后第3周行日间手术的可行性良好。

关键词：儿童新型冠状病毒手术时间可行性研究

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采用可达域覆盖的多航天器协同护卫策略

国防科技大学学报 2024年第3期46卷 12-20页

作者：张润德蔡伟伟杨乐平朱彦伟国防科技大学空天科学学院湖南长沙410073

针对高轨高价值目标护卫问题,提出了一种基于可达域覆盖的多航天器协同护卫策略。从相对运动视角对协同护卫任务进行了描述,并将威胁源多脉冲机动可达域问题建模为凸优化问题求解。在滚动优化框架下,根据动态更新的威胁源终端可达域,设... 详细信息

针对高轨高价值目标护卫问题,提出了一种基于可达域覆盖的多航天器协同护卫策略。从相对运动视角对协同护卫任务进行了描述,并将威胁源多脉冲机动可达域问题建模为凸优化问题求解。在滚动优化框架下,根据动态更新的威胁源终端可达域,设计协同护卫平面及护卫点,以此为终端位置约束构建多航天器协同轨迹规划模型,生成相应护卫轨迹。仿真结果表明,所提出的可达域分析方法能够快速计算威胁源终端可达域,协同护卫策略在多个场景下均能有效阻止威胁源,且护卫成功率随护卫航天器机动能力增强而增大。

关键词：协同护卫策略凸优化滚动优化可达域

数字技能如何影响农民电商参与行为?--基于信息获取的中介效应分析

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中国农业大学学报 2024年第4期29卷 81-93页

作者：蒋洁洁青平蔡炜炜黄帆华中农业大学经济管理学院武汉430070

为探究数字技能对农民电商参与行为的影响及作用机制,基于2020年中国乡村振兴综合调查(CRRS)数据,立足“手段-自由-成就”的可行信息能力理论,构建“数字技能-信息获取-电商参与”的理论分析框架,采用二元Probit、Tobit和中介效应等分... 详细信息

为探究数字技能对农民电商参与行为的影响及作用机制,基于2020年中国乡村振兴综合调查(CRRS)数据,立足“手段-自由-成就”的可行信息能力理论,构建“数字技能-信息获取-电商参与”的理论分析框架,采用二元Probit、Tobit和中介效应等分析方法,从信息获取的中介视角实证检验数字技能对农民电商参与决策及程度的影响,并进行稳健性检验和异质性分析。结果表明:1)数字技能对农民电商参与决策和程度均具有显著正向影响;2)信息获取在数字技能对农民电商参与决策和程度的影响中存在部分中介效应,中介效应占总效应的比重分别为11.76%和11.73%;3)数字技能对收入水平较高、受教育水平较高的农民,电商参与决策和参与程度的正向影响更为显著。政府应从有效提升农民数字技能水平,稳步实现信息获取自由,加强关注农民内部分化3方面提升农民电商参与率和程度。

关键词：数字技能电商参与决策电商参与程度信息获取