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A guidance method for coplanar orbital interception based on reinforcement learning

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Journal of Systems Engineering and Electronics 2021年第4期32卷 927-938页

作者： zeng xin ZHU Yanwei YANG Leping ZHANG chengming College of Aeronautics and Astronautics National University of Defense TechnologyChangsha 410073China

This paper investigates the guidance method based on reinforcement learning(RL)for the coplanar orbital interception in a continuous low-thrust *** problem is formulated into a Markov decision process(MDP)model,then a welldesigned RL algorithm,experience based deep deterministic policy gradient(EBDDPG),is proposed to solve *** taking the advantage of prior information generated through the optimal control model,the proposed algorithm not only resolves the convergence problem of the common RL algorithm,but also successfully trains an efficient deep neural network(DNN)controller for the chaser spacecraft to generate the control *** simulation results show that the proposed algorithm is feasible and the trained DNN controller significantly improves the efficiency over traditional optimization methods by roughly two orders of magnitude.

关键词： orbital interception reinforcement learning(RL) Markov decision process(MDP) deep neural network(DNN)

An optimal guidance method for free-time orbital pursuit-evasion game

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Journal of Systems Engineering and Electronics 2022年第6期33卷 1294-1308页

作者： ZHANG chengming ZHU Yanwei YANG Leping zeng xin College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410000China

With the development of space rendezvous and proximity operations(RPO)in recent years,the scenarios with noncooperative spacecraft are attracting the attention of more and more researchers.A method based on the costate normalization technique and deep neural networks is presented to generate the optimal guidance law for free-time orbital pursuit-evasion ***,the 24-dimensional problem given by differential game theory is transformed into a three-parameter optimization problem through the dimension-reduction method which guarantees the uniqueness of solution for the specific ***,a close-loop interactive mechanism involving feedback is introduced to deep neural networks for generating precise initial *** the optimal guidance law is obtained efficiently and stably with the application of optimization algorithm initialed by the deep neural ***,the results of the comparison with another two methods and Monte Carlo simulation demonstrate the efficiency and robustness of the proposed optimal guidance method.

关键词： orbital pursuit-evasion differential game dimension-reduction deep neural networks

A DNN based trajectory optimization method for intercepting non-cooperative maneuvering spacecraft

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Journal of Systems Engineering and Electronics 2022年第2期33卷 438-446页

作者： YANG Fuyunxiang YANG Leping ZHU Yanwei zeng xin College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

Current successes in artificial intelligence domain have revitalized interest in neural networks and demonstrated their potential in solving spacecraft trajectory optimization problems. This paper presents a data-free deep neural network(DNN) based trajectory optimization method for intercepting noncooperative maneuvering spacecraft, in a continuous low-thrust scenario. Firstly, the problem is formulated as a standard constrained optimization problem through differential game theory and minimax principle. Secondly, a new DNN is designed to integrate interception dynamic model into the network and involve it in the process of gradient descent, which makes the network endowed with the knowledge of physical constraints and reduces the learning burden of the network. Thus, a DNN based method is proposed, which completely eliminates the demand of training datasets and improves the generalization capacity. Finally, numerical results demonstrate the feasibility and efficiency of our proposed method.

关键词： non-cooperative maneuvering spacecraft neural network differential game trajectory optimization

Intelligent Diagnosis Method for Typical Co-frequency Vibration Faults of Rotating Machinery Based on SAE and Ensembled ResNet-SVM

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 215-230页

作者： Xiancheng Zhang xin Pan Hao zeng Haofu Zhou Beijing Key Laboratoryof Health Monitoring and Self-recovery for High-end Mechanical Equipment Beijing University of Chemical TechnologyBeijing 100029China Engineering Research Center of Chemical Safety(Ministry of Education) Beijing University of Chemical TechnologyBeijing 100029China Engineering Management Department of China Three Gorges New Energy(Group)Co. Ltd.Beijing 101199China

Intelligent fault diagnosis is an important method in rotating machinery fault diagnosis and equipment health *** deal with co-frequency vibration faults,a type of typical fault in rotating machinery,this paper proposes a fault diagnosis method based on the stacked autoencoder(SAE)and ensembled ***,the time-and frequency-domain features of several co-frequency vibration faults are summarized based on the mechanism analysis and calculated using actual vibration *** realize and validate the high-precision diagnosis method of rotating equipment with co-frequency faults proposed in this study,the following three criteria are required:First,to improve the effectiveness and robustness of the ensembled model and the sliding window using data augmentation,adding noise,autoencoder(AE)and SAE methods are analyzed in terms of principle and practical ***,ResNet is used as the feature extractor for the ensembled ResNet-SVM *** extraction is carried out twice,and the extracted co-frequency fault features are more ***,the data augmentation method and ensemble ResNet-SVM are combined for fault diagnosis and compared with other *** experimental results show that the accuracy of the proposed method can exceed 99.9%.

关键词： Co-frequency vribation Data argumentation Ensembeled ResNet-SVM High precision fault diagnosis

Screening of Highly Effective Sinorhizobium meliloti Strains for 'Vector' Alfalfa and Testing of Its Competitive Nodulation Ability in the Field

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Pedosphere 2007年第2期17卷 219-228页

作者： zeng Zhao-Hai chen Wen-xin HU Yue-Gao SUI xin-Hua chen Dan-Ming College of Agronomy and Biotechnology China Agricultural University Beijing 100094 （China） College of Biology/Key Laboratory of Agro-Microbial Resource and Application Ministry of Agriculture China Agricultural University Beijing 100094 （China）

Seventeen Sinorhizobium meliloti strains from seven provinces in China were used to screen highly effective strains for alfalfa cultivar in a greenhouse study and their symbiotic relationship and competitive ability were studied in the field. CCBAU30138 was the most effective strain, as evidenced by increase in dry weights. A field experiment showed that the inoculation of alfalfa with CCBAU30138 resulted in increases of 11.9% and 19.6% of dry matter production and crude protein production, respectively, in forage of monocultured plants. The total dry matter yields of alfalfa and tall fescue in binary culture were increased by 16.3% by inoculation of alfalfa with this strain. These results showed that S. rneliloti strain CCBAU30138 was an effective inoculant both in the greenhouse and in the field. The analysis of randomly amplified polymorphic DNA （RAPD） by polymerase chain reaction （PCR） from nodule extracts showed that the strain CCBAU30138 had high competitiveness in the field. It occupied 47.5% of nodules in alfalfa monoculture and 44.4% of nodules in alfalfa-tall fescue binary culture after 20 weeks of growth. In conclusion, a simple system to select highly effective and competitive symbiotic strains specific to alfalfa was established. Using this system, a *** suitable for the alfalfa cultivar ‘Vector＇ grown in Wuqiao County of Hebei Province was obtained.

关键词： alfalfa inoculant selection Sinorhizobium meliloti tall fescue

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开展全科教育干预研究:从设计到发表

中国全科医学 2025年第4期28卷 413-419,426页

作者：邹川欧健铭曾欣彭涛周燕肖纯瑶陶洪霞陈庆奇林恺四川省成都市第五人民医院全科医学科 611130 成都中医药大学医学与生命科学学院四川省成都市611137 联合医务中国广东省深圳市518000 汕头大学医学院第一附属医院全科医学科广东省汕头市515041

随着中国基层医疗的发展,近10年中国将培养近40万全科医生,其中培养具有胜任力的全科医生至关重要,这需要全科教育者探索大量适合中国且基于证据的全科教育理念、方法和内容。目前,国内全科教育干预研究的质量较差,大部分全科教育师资... 详细信息

随着中国基层医疗的发展,近10年中国将培养近40万全科医生,其中培养具有胜任力的全科医生至关重要,这需要全科教育者探索大量适合中国且基于证据的全科教育理念、方法和内容。目前,国内全科教育干预研究的质量较差,大部分全科教育师资和研究者尚缺乏教育干预研究的相关培训。本文旨在介绍全科教育干预研究,按照从设计到发表的流程将研究分为4个阶段,共13个步骤:4个阶段分别为构建研究问题(产生研究灵感、文献综述、融入理论/概念框架、精炼研究问题)、研究设计(试验设计、干预措施、结果评估)、研究执行(建立研究团队、获取研究资源、申请研究伦理、项目实施)、发表和评价阶段(文章撰写、反思与评价),以期为全科教育研究者与实践者开展教育干预研究提供研究方法和思路,产生高质量的教育研究“证据”,进一步改善全科教育培训质量,培养具有胜任力的全科医生。

关键词：全科医学教育,医学教育研究干预性研究研究方法

维普期刊数据库博看期刊

Physical origins of ruled surfaces on the reduced density matrices geometry

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Science China(Physics,Mechanics & Astronomy) 2017年第2期60卷 1-8页

作者： Ji-Yao chen Zhengfeng Ji Zheng-xin Liu Xiaofei Qi Nengkun Yu Bei zeng Duanlu Zhou State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing 100084 China Perimeter Institute for Theoretical Physics Waterloo N2L 2Y5 Canada Centre for Quantum Computation ＆ Intelligent Systems School of Software Faculty of Engineering and Information Technology University of Technology Sydney Sydney 2007 Australia State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China Department of Physics Renmin University of China Beijing 100872 China Department of Mathematics Shanxi University Taiyuan 030000 China Institute for Quantum Computing University of Waterloo Waterloo N2L 3G1 Canada Department of Mathematics ＆ Statistics University of Guelph Guelph N1G 2W1 Canada Institute of Physics Chinese Academy of Sciences Beijing 100190 China

The reduced density matrices （RDMs） of many-body quantum states form a convex set. The boundary of low dimensional projections of this convex set may exhibit nontrivial geometry such as ruled surfaces. In this paper, we study the physical origins of these ruled surfaces for bosonic systems. The emergence of ruled surfaces was recently proposed as signatures of symmetry- breaking phase. We show that, apart from being signatures of symmetry-brealdng, ruled surfaces can also be the consequence of gapless quantum systems by demonstrating an explicit example in terms of a two-mode Ising model. Our analysis was largely simplified by the quantum de Finetti＇s theorem--in the limit of large system size, these RDMs are the convex set of all the symmetric separable states. To distinguish ruled surfaces originated from gapless systems from those caused by symmetry- breaking, we propose to use the finite size scaling method for the corresponding geometry. This method is then applied to the two-mode XY model, successfully identifying a ruled surface as the consequence of gapless systems.

关键词： ruled surfaces reduced density matrices bosonic system geometry

Robust trajectory planning for UAV communication systems in the presence of jammers

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Chinese Journal of Aeronautics 2022年第10期35卷 265-274页

作者： Lingyun ZHOU Xiaotong ZHAO xin GUAN Enbin SONG xin zeng Qingjiang SHI School of Software Engineering Tongji UniversityShanghai 200092China College of Mathematics and School of Aeronautics and Astronautics Sichuan UniversityChengdu 610064China Department of Information and Communication Engineering Tongji UniversityShanghai 200092China

Unmanned Aerial Vehicle(UAV)has emerged as a promising novel application for the Sixth-Generation(6G)wireless communication by leveraging more favorable Line-of-Sight(Lo S)***,the jamming resistance by exploiting UAV’s mobility is a new challenge in the UAV-ground *** paper investigates the trajectory planning problem in an UAV communication system,where the UAV is operated by a Ground Control Unit(GCU)to perform certain tasks in the presence of multiple jammers with imperfect power and location *** ensure the reliability of the GCU-to-UAV link,we formulate the problem as a non-convex semi-infinite optimization,aiming to maximize the average worst-case Signal-toInterference-plus-Noise Ratio(SINR)over a given flight duration by designing the robust trajectory of the UAV under stringent energy availability *** handle this problem efficiently,we develop an iterative algorithm for the solution with the aid of S-procedure and Successive Convex Approximation(SCA)*** results demonstrate the efficacy of our proposed algorithm and offer some useful design insights to practical system.

关键词： 6G UAV communications Jamming resistance Trajectory optimization Robust design Non-convex optimization

Body attributes of both parents jointly affect offspring sex allocation in a socially monogamous, size-monomorphic passerine

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Current Zoology 2013年第2期59卷 271-277页

作者： xin LU Xianhai zeng Bo DU Department of Zoology College of Life Sciences Wtthan University Wuhan 430072 China

Theory predicts that because males are more variable in reproductive success than females, a mother should produce more sons to maximize fitness return from the sex allocation if she is of high-quality （the female quality hypothesis） or mates with a high-quality male （the male quality hypothesis）. While most previous studies have looked at each hypothesis, we tested both of them simultaneously in the white-rumped snowfinch Montifringilla taczanowskii, a socially monogamous, sexually monomorphic passerine where body size is a potential indicator of individual quality in intrasexual competition and territory de- fense. Brood sex ratios at the population level did not deviate from random expectation. Among individual broods, the proportion of sons did not depend on body size of either male or female parent, but on interaction of this trait of both parents. Further analy- ：~es revealed that brood sex ratios were independent of body size of male or female parents when their mates were smaller, but positively related with body size of male or female parents when their mates were larger. These results suggest that mechanisms underlying the two hypotheses may act jointly on offspring sex allocation. The mechanisms are expected to evolve through size-assortative mating which is often reached by sexual selection [Current Zoology 59 （2）： 271-277, 2013].

关键词： Brood sex ratio Parental quality Size-assortative mating White-rumped snowfinch