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On the use of H-inf criterion in channel estimation and precoding in massive MIMO systems

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Science China(Information Sciences) 2017年第2期60卷 151-164页

作者： peng XU Dongming WANG feng QI School of Computer Science and Engineering Northeastern University National Mobile Communications Research Laboratory Southeast University Key Laboratory of Opto-Electronic Information Processing Institute of AutomationChinese Academy of Science

In this paper, a channel estimation(CE) and precoding scheme by using H-infinity(H-inf) criterion for mitigation of pilot contamination(PC) in massive multiple input multiple output(MIMO) orthogonal frequency division multiplexing(OFDM) systems is investigated. Firstly, different thresholds in H-inf CE and precoding are considered. Secondly, asymptotic analysis is presented to simplify the H-inf precoding, which shows that the complexity of an order of magnitude is reduced. Thirdly, approximate downlink achievable data rates per user are studied for different CE and precoding schemes, such as H-inf and minimum mean square error(MMSE) CE, MMSE, zero-forcing(ZF) and H-inf precoding. The analysis shows that the proposed scheme can provide dual mitigation to the PC. That is, the H-inf CE mitigates the PC by adjusting its thresholds, and the H-inf precoding is utilized to suppress the PC by considering inter-cell interference. The numerical results show that joint use of H-inf CE and H-inf precoding outperforms existing schemes in terms of mitigation to the PC.

关键词： massive MIMO pilot contamination precoding channel estimation H-inf

Structure, characterization, and dynamic performance of a wet air oxidation catalyst Cu–Fe–La/γ-Al_2O_3

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Chinese Journal of Chemical Engineering 2016年第9期24卷 1171-1177页

作者： Yongli Zhang feng peng Yanbo Zhou School of Chemistry and Chemical Engineering South China University of Technology School of Chemical and Environmental Engineering Hanshan Normal University

A Cu–Fe–La/γ-Al_2O_3(CFLA) catalyst was prepared by the excessive impregnation method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results indicate that the catalyst contained mostly Cu^(2+), Fe^(3+), and La^(3+)and a small amount of Cu^+, Fe^(2+), and La. The active components were uniformly distributed in the catalyst, and the particle size of the components was approximately 7.5 nm. The CFLA catalyst was used for the treatment of methyl orange(MO) solution by catalytic wet air oxidation(CWAO), and it exhibited a high catalytic activity. The catalytic reaction involved variable valence states of metals and free-radical reaction mechanism. The CWAO reaction of MO solution was fitted by a segmented first-order dynamic model, and the rapid reaction apparent activation energy was 13.9 k J·mol^(-1).

关键词： Catalytic wet air oxidation Catalyst Activity Reaction mechanism Kinetics Waste water

On extended state Kalman filter-based identification algorithm for aerodynamic parameters

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Control Theory and Technology 2024年第2期22卷 235-243页

作者： Wenyan bai Ruizhe Jia peng Yu Wenchao Xue Beijing Aerospace Automatic Control Institute Beijing100854China School of Automation and Electrical Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of Knowledge Automation for Industrial Processes Ministry of EducationBeijing100083China Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing100190China

In this paper, the problem of time-varying aerodynamic parameters identification under measurement noises is studied. By analyzing the key aerodynamic parameters that affect the aircraft control system, a system model with extended states for identifying equivalent aerodynamic parameters is established, and error parameters are extended to the system state, avoiding the difficulty caused by the unknown dynamic in the system. Furthermore, an identification algorithm based on extended state Kalman filter is designed, and it is proved that the algorithm has quasi-consistency, thus, the estimation error can be evaluated in real time. Finally, the simulation results under typical flight scenarios show that the designed algorithm can accurately identify aerodynamic parameters, and has desired convergence speed and convergence precision.

关键词： Aerodynamic parameters Parameter identification Extended state Kalman filter

UV-Vis-NIR Light-deformable Shape-memory Polyurethane Doped with Liquid-crystal Mixture and GO towards Biomimetic Applications

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Chinese Journal of Polymer Science 2022年第2期40卷 166-174页

作者： peng Zhang feng Cai Guo-Jie Wang Hai-feng Yu School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Institute of New Structural Materials School of Materials Science and Engineeringand Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationPeking UniversityBeijing 100871China

Nature has been inspiring material researchers to fabricate biomimetic functional devices for various applications, and shape-memory polymer materials(SMPMs) have received tremendous attention since the promising intelligent materials possess more advantages over others for the fabrication of biomimetic functional devices. As is well-known, SMPMs can be stimulated by heat, electricity, magnetism, pH, solvent and light. From the viewpoint of practical applications, ultraviolet(UV)-visible(Vis)-near infrared(NIR) light-responsive SMPMs are undoubtedly more advantageous. However, up to now, UV-Vis-NIR light-deformable SMPMs by combining photothermal and photochemical effects are still rarely reported. Here we designed a UV-Vis-NIR light-deformable SMP composite film via incorporating a liquid crystal(LC) mixture and graphene oxide(GO) into a shape-memory polyurethane matrix. The elongated composite films exhibited interesting photomechanical bending deformations with different light-triggered mechanisms,(1) photochemically induced LC phase transition upon UV exposure,(2) photochemically and photothermally induced LC phase transition upon visible-light irradiation,(3) photothermally triggered LC phase transition and partial stress relaxation upon low-intensity NIR exposure. All the deformed objects could recover to their original shapes by high-intensity NIR ***, the biomimetic circadian rhythms of acacia leaves and the biomimetic bending/spreading of fingers were successfully achieved, which could blaze a way in the field of biomimetic functional devices due to the excellent light-deformable and shape-memory properties of the SMP composite films.

关键词： UV-Vis-NIR Light-deformable Shape-memory Liquid-crystal Biomimetic functional device

Machining dynamics and chatters in micro-milling:A critical review on the state-of-the-art and future perspectives

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Chinese Journal of Aeronautics 2024年第7期37卷 59-80页

作者： Qingshun bai peng WANG Kai CHENG Liang ZHAO Yabo ZHANG School of Mechanical and Electrical Engineering Harbin Institute of TechnologyHarbin 150001China Department of Mechanical and Aerospace Engineering Brunel University LondonUxbridge UB83PHUK

Micro-milling technology is widely applied in micro manufacturing,particularly for the fabrication of miniature and micro ***,the chatters and machining dynamics related issues in micro-milling are often the main challenges restricting its machining quality and *** research works have rendered that the machining dynamics and chatters in micro-milling are more complex compared with the conventional macro-milling process,likely because of the size effect and rigidity of the micro-milling system including the tooling,workpiece,process variables,materials involved,and the high-speed milling machines,and further their collective dynamic ***,in this paper,the state of the art focusing on micro-milling chatters and dynamics related issues over the past years are comprehensively and critically reviewed to provide some insights for potential researchers and ***,typical applications and the problems caused by the machining dynamics and chatters in micro-milling have been put forward in this ***,the research on the underlying micro-cutting mechanics and dynamics,stability analysis,chatters detection,and chatter suppression are summarized ***,the underlying scientific and technological challenges are discussed particularly against typical precision engineering ***,the possible future directions and trends in research and development of micro-milling have been discussed.

关键词： Micro-milling Machining dynamics Micro-cutting mechanics Stability lobe diagram(SLD) Chatters suppression Digital twin

Aeroacoustic and aerodynamic optimization of propeller blades

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Chinese Journal of Aeronautics 2020年第3期33卷 826-839页

作者： Peixun YU Jiahui peng Junqiang bai Xiao HAN Xiang SONG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Unmanned System Research Institute Northwestern Polytechnical UniversityXi’an 710072China

It is of great significance to develop a high-efficiency and low-noise propeller optimization method for new-generation propeller aircraft *** with free form deformation method,dynamic mesh interpolation technology,optimization algorithm,surrogate model,aerodynamic calculation and aeroacoustic prediction model module,the integrated aerodynamic and aeroacoustic design method of propeller is *** optimization design for the six-blade propeller is carried *** non-reduction in efficiency,thrust coefficient and the minimum of aerodynamic noise is treated as the optimization design *** spatial vorticity distribution of the propeller before and after the design is also analyzed by using unsteady computational fluid dynamics *** results show that the optimized propeller can effectively reduce the aerodynamic noise *** maximum total sound pressure level can be reduced by 5 dB without reducing its aerodynamic *** developed method has good application potential in low-noise optimization design of propeller and other rotating machinery.

关键词： Aeroacoustic Aerodynamic Dynamic mesh interpolation technology Free form deformation method Optimization algorithm Propeller Sound pressure level Surrogate model

Product platform architecture for cloud manufacturing

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Advances in Manufacturing 2020年第3期8卷 331-343页

作者： Wei Wei feng Zhou peng-Fei Liang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191People’s Republic of China

Cloud manufacturing is emerging as a new manufacturing paradigm and an integrated *** adapt to the increasing challenges of the traditional manufacturing industry transforming toward service-oriented and innovative manufacturing,this paper proposes a product platform architecture based on cloud ***,a framework for the product platform for cloud manufacturing was *** proposed architecture is composed of five layers:resource,cloud technology,cloud service,application,and user ***,several key enabling technologies for forming the product platform were ***,the product platform for cloud manufacturing built by a company was taken as an application example to illustrate the architecture and functions of the *** validity and superiority of the architecture were verified.

关键词： Cloud manufacturing Cloud service Product platform Architecture Product collaborative design

Modelling and Optimizing Motherboard Functional Testing in Laptop Manufacturing

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Journal of Systems Science & Complexity 2024年第6期37卷 2406-2423页

作者： bai peng KANG Yu WANG Kangcheng ZHAO Yunbo DONG Shaojie Department of Automation University of Science and Technology of ChinaHefei 230026China Department of Automation&Institute of Advanced Technology University of Science and Technology of ChinaHefei 230026China Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefei 230088China Institute of Advanced Technology University of Science and Technology of ChinaHefei 230026China

Functional testing is key to fulfill quality control in laptop manufacturing and is of great economic ***,due to the unavailability of practical data,mathematical model and systematic perspective,it has barely been touched from the academic community to *** the first time,this work provides technical understanding of the key principles of functional testing,mathematically models the general framework,elucidates existing testing strategy under the proposed framework and model,and finally proposes a specified optimization strategy which outperforms existing *** work lays the model foundation for the further optimization of functional testing,and can be regarded as a good example of how a systematic approach can solve practical industrial challenges.

关键词： Laptop manufacturing modelling motherboard functional testing optimization

Recognition of Biotin-functionalized Liposomes

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Chinese Chemical Letters 2003年第8期14卷 832-835页

作者： Hai feng ZHU Jun bai LI International Joint Lab The Center for Molecular ScienceInstitute of ChemistryChinese Academy of SciencesBeijing 100080

Functionalized liposomes were prepared by mixing the biotin in the lipid vesicle suspensions. The experiments through immersing streptavidin deposited mica into the biotin modified liposome solution testify the spec... 详细信息

关键词： Recognition liposome TEM AFM.