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Robust Global Stabilization of Spacecraft Rendezvous System via Gain Scheduling

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International Journal of Automation and computing 2014年第4期11卷 426-433页

作者： qian Wang Guang-Ren duan Center for Control Theory and Guidance Technology Harbin Institute of Technology

The problem of robust global stabilization of a spacecraft circular orbit rendezvous system with input saturation and inputadditive uncertainties is studied in this paper. The relative models with saturation nonlinearity are established based on ClohesseyWiltshire equation. Considering the advantages of the recently developed parametric Lyapunov equation-based low gain feedback design method and an existing high gain scheduling technique, a new robust gain scheduling controller is proposed to solve the robust global stabilization problem. To apply the proposed gain scheduling approaches, only a scalar nonlinear equation is required to be *** from the controller design, simulations have been carried out directly on the nonlinear model of the spacecraft rendezvous operation instead of a linearized one. The effectiveness of the proposed approach is shown.

关键词： Robust global stabilization spacecraft rendezvous system parametric Lyapunov equation input saturation input-additive uncertainties gain scheduling

Output Feedback Stabilization of Spacecraft Autonomous Rendezvous Subject to Actuator Saturation

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International Journal of Automation and computing 2016年第5期13卷 428-437页

作者： qian Wang Guang-Ren duan Center for Control Theory and Guidance Technology Harbin Institute of Technology

This paper studies the output feedback dynamic gain scheduled control for stabilizing a spacecraft rendezvous system subject to actuator saturation. By using the parametric Lyapunov equation and the gain scheduling technique, a new observer-based output feedback controller is proposed to solve the semi-global stabilization problem for spacecraft rendezvous system with actuator saturation. By scheduling the design parameter online, the convergence rates of the closed-loop system are improved. Numerical simulations show the effectiveness of the proposed approaches.

关键词： Dynamic gain scheduling output feedback parametric Lyapunov equation input saturation spacecraft rendezvous.

Exploring sensitive area in the tropical Indian Ocean for El Niño prediction: implication for targeted observation

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Journal of Oceanology and Limnology 2020年第6期38卷 1602-1615页

作者： ZHOU qian duan Wansuo HU Junya National Marine Environmental Forecasting Center Ministry of Natural ResourcesBeijing 100081China Key Laboratory of Research on Marine Hazards Forecasting National Marine Environmental Forecasting CenterBeijing 100081China LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China

Based on initial errors of sea temperature in the tropical Indian Ocean that are most likely to induce spring predictability barrier(SPB)for the El Niño prediction,the sensitive area of sea temperature in the tropical Indian Ocean for El Niño prediction starting from January is identified using the CESM1.0.3(Community Earth System Model),a fully coupled global climate *** sensitive area locates mainly in the subsurface of eastern Indian *** effectiveness of applying targeted observation in the sensitive area is also evaluated in an attempt to improve the El Niño prediction *** results of sensitivity experiments indicate that if initial errors exist only in the tropical Indian Ocean,applying targeted observation in the sensitive area in the Indian Ocean can significantly improve the El Niño *** particular,for SPB-related El Niño events,when initial errors of sea temperature exist both in the tropical Indian Ocean and the Pacific Ocean,which is much closer to the realistic predictions,if targeted observations are conducted in the sensitive area of tropical Pacific,the prediction skills of SPB-related El Niño events can be improved by 20.3%in ***,if targeted observations are conducted in the sensitive area of tropical Indian Ocean in addition,the improvement of prediction skill can be increased by 25.2%.Considering the volume of sensitive area in the tropical Indian Ocean is about 1/3 of that in the tropical Pacific Ocean,the prediction skill improvement per cubic kilometer in the sensitive area of tropical Indian Ocean is competitive to that of the tropical Pacific *** to the sensitive area of the tropical Pacific Ocean,sensitive area of the tropical Indian Ocean is also a very effective and cost-saving area for the application of targeted observations to improve El Niño forecast skills.

关键词： tropical Indian Ocean El Niño prediction sensitive area targeted observation

Incremental join view maintenance on distributed log-structured storage

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Frontiers of Computer Science 2021年第4期15卷 105-120页

作者： Huichao duan Huiqi HU Weining qian Aoying ZHOU School of Data Science and Engineering East China Normal UniversityShanghai 200062China

Modern database systems desperate for the ability to support highly scalable transactions and efficient queries simultaneously for real-time *** solution is to utilize query optimization techniques on the on-line transaction processing(OLTP)*** materialized view is considered as a panacea to decrease query ***,it also involves the significant cost of maintenance which trades away transaction *** this paper,we examine the design space and conclude several design features for the implementation of a view on a distributed log-structured merge-tree(LSMtree),which is a well-known structure for improving data write *** a result,we develop two incremental view maintenance(IVM)approaches on *** avoids join computation in view maintenance *** with two optimizations is proposed to decouple the view maintenance with the transaction *** the asynchronous update,we also provide consistency queries for *** on TPC-H benchmark show our methods achieve better performance than straightforward methods on different workloads.

关键词： materialized views asynchronous maintenance hybrid transaction and analytical process LSM-tree

Multi-Objective Optimization for an Industrial Grinding and Classification Process Based on PBM and RSM

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IEEE/CAA Journal of Automatica Sinica 2023年第11期10卷 2124-2135页

作者： Xiaoli Wang Luming Liu Lian duan qian Liao School of Automation Central South universityChangsha 410083China Changsha Research Institute of Mining and Metallurgy Changsha 410012China

The grinding and classification process is one of the key sub-processes in mineral processing, which influences the final process indexes significantly and determines energy and ball consumption of the whole plant. Therefore, optimal control of the process has been very important in practice. In order to stabilize the grinding index and improve grinding capacity in the process,a process model based on population balance model(PBM) is calibrated in this study. The correlation between the mill power and the operating variables in the grinding process is modelled by using the response surface method(RSM), which solves the problem where the traditional power modeling method relies on some unobservable mechanism-related parameters. On this basis, a multi-objective optimization model is established to maximize the useful power of the grinding circuit to improve the throughput of the grinding operation and improve the fraction of –0.074 mm particles in the hydrocyclone overflow to smooth the subsequent flotation operation. The elite non-dominated sorting genetic algorithm-II(NSGA-II) is then employed to solve the multi-objective optimization problem. Finally, subjective and objective weighting methods and integrated multi-attribute decision-making methods are used to select the optimal solution on the Pareto optimal solution set. The results demonstrate that the throughput of the mill and the fraction of –0.074 mm particles in the overflow of the cyclone are increased by 3.83 t/h and 2.53%, respectively.

关键词： Decision-making technique grinding process multiobjective optimization response surface method(RSM)

A Frequency Domain Based Signal Combining Method for Distributed Antenna Arraying

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China Communications 2019年第8期16卷 176-184页

作者： Chaowei duan Yafeng Zhan qian Kong Space Center Tsinghua UniversityBeijing 100080China Beijing National Research Center for information Science and Technology (BNRist) Beijing 100080China Guangzhou Haige Communications Group Incorporated Company Guangzhou 510000China

Distributed antenna arraying is a promising technology for weak signal reception. The received signals from different antennas are aligned and combined to improve the receiving signal-to-noise ratio(SNR). However, the combining performance is serious degraded by the difference of sampling frequency between antennas. In this paper, a frequency domain based signal combining method is proposed to solve this problem. The unaligned sampled data in time domain of the received signals are transformed to frequency domain using fast Fourier transform(FFT). The received signals can be aligned in frequency domain when their spectrum resolutions are the same. Therefore the received signals with the same total sampling time can be aligned and combined in frequency domain and then the combined signal is recovered using inverse fast Fourier transform(IFFT). Numerical simulations with two typical modulation types, i.e., PSK and PCM/BPSK/PM, prove the validity and robustness of this method.

关键词： weak signal reception distributed antenna arraying signal combining fast fourier transform

LiF and LiNO_(3) as synergistic additives for PEO-PVDF/LLZTO-based composite electrolyte towards high-voltage lithium batteries with dualinterfaces stability

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Journal of Energy Chemistry 2022年第2期31卷 319-328页

作者： Liansheng Li Yuanfu Deng Huanhuan duan Yunxian qian Guohua Chen The Key Laboratory of Fuel Cell for Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640GuangdongChina Electrochemical Energy Engineering Research Center of Guangdong Province South China University of TechnologyGuangzhou 510640GuangdongChina Shenzhen CAPCHEM Technol Co Ltd. Shenzhen 518118GuangdongChina Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina

Solid electrolytes with desirable properties such as high ionic conductivity,wide electrochemical stable window,and suitable mechanical strength,and stable electrode-electrolyte interfaces on both cathode and anode side are essential for high-voltage all-solid-state lithium batteries(ASSLBs)to achieve excellent cycle *** this work,a novel strategy of using LiF and LiNO_(3) as synergistic additives to boost the performance of PEO-PVDF/LLZTO-based composite solid electrolytes(CSEs)is developed,which also promotes the assembled high-voltage ASSLBs with dual-interfaces stability ***,LiF as an inactive additive can increase the electrochemical stability of the CSE under high cut-off voltage,and improve the high-voltage compatibility between cathode and CSE,thus leading to a stable cathode/CSE ***_(3) as an active additive can lead to an enhanced ionic conductivity of CSE due to the increased free-mobile Li+and ensure a stable CSE/Li interface by forming stable solid electrolyte interphase(SEI)on Li anode *** from the improved performance of CSE and stable dualinterfaces,the assembled NCM622/9[PEO_(15)-LiTFSI]-PVDF-15 LLZTO-2 LiF-3 LiNO_(3)/Li cell delivers a high rate capacity of 102.1 mAh g^(-1) at 1.0 C and a high capacity retention of 77.4%after 200 cycles at 0.5 C,which are much higher than those of the ASSLB assembled with additive-free CSE,with only 60.0 mAh g^(-1) and 52.0%,***,novel cycle test modes of resting for 5 h at different charge states after every 5 cycles are designed to investigate the high-voltage compatibility between cathode and CSE,and the results suggest that LiF additive can actually improve the high-voltage compatibility of cathode and *** the obtained results confirm that the strategy of using synergistic additives in CSE is an effective way to achieve high-voltage ASSLBs with dual-interfaces stability.

关键词： Synergistic additives Composite solid electrolyte Dual-interfaces stability High-voltage cathode Lithium metal battery

Community-Based User Domain Model Collaborative Recommendation Algorithm

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Tsinghua Science and Technology 2013年第4期18卷 353-359页

作者： Fulan qian Yanping Zhang Yuan Zhang Zhen duan the School of Computer Science and Technology Anhui University the School of Electronic and Information Engineering Anhui Jianzhu University

Collaborative Filtering （CF） is a commonly used technique in recommendation systems. It can promote items of interest to a target user from a large selection of available items. It is divided into two broad classes： memory-based algorithms and model-based algorithms. The latter requires some time to build a model but recommends online items quickly, while the former is time-consuming but does not require pre-building time. Considering the shortcomings of the two types of algorithms, we propose a novel Community-based User domain Collaborative Recommendation Algorithm （CUCRA）. The idea comes from the fact that recommendations are usually made by users with similar preferences. The first step is to build a user-user social network based on users＇ preference data. The second step is to find communities with similar user preferences using a community detective algorithm. Finally, items are recommended to users by applying collaborative filtering on communities. Because we recommend items to users in communities instead of to an entire social network, the method has perfect online performance. Applying this method to a collaborative tagging system, experimental results show that the recommendation accuracy of CUCRA is relatively good, and the online time-complexity reduces to O.（n）.

关键词： collaborative recommendation tagging system community-based recommendation system

CORRESPONDENCE ANALYSIS ON IMAGES OF JIANGXI PROVINCE AS A TOURIST DESTINATION

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Chinese Geographical Science 2005年第3期15卷 275-280页

作者： MAO duan-qian ZHANG Jie BAO Hao-sheng Department of Urban and Resources Sciences Nanjing University Nanjing 210093 P. R. China Department of Geography Jiangxi Normal University Nanchang 330027 P. R. China

This paper delineates the images of Jiangxi Province as tourist destination perceived by about 2000 sample visitors at Lushan Mountain and other 3 famous resorts (Jinggangshan Mountains, Longhushan Mountain, and Sanqingshan Mountain), with a result that the most common image is the famous scenic mountain image with partial attribute of image of religious culture destination. In order to reveal the similarities and dissimilarities of images among the four destinations, a correspondence analysis on 16 image attributes was employed. The results indicate that the tourists’ images on Longhushan Mountain, Sanqingshan Mountain and Lushan Mountain are very similar: having a lot of good tourist sites, famous mountain scenery, being close to nature and having good guide service, and others, but religious culture and good shopping facilities having not made deep impression on tourist, while Jinggangshan Mountains is famous for its red culture. The correspondence analysis visualizes the strengths and weaknesses of the destinations, which is useful for market positioning among the competitive places. Finally, some marketing suggestions for the four destinations were provided.

关键词： tourist destination image cognitive attribute evaluative attribute correspondence analysis