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On Dynamic Channel Emulation in Sector MPAC for Over-the-Air Testing of Beamformed Massive MIMO Devices

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China Communications 2023年第4期20卷 41-56页

作者： Xiaochen Chen Heng wang Weimin WANG Zheng Liu Yuanan Liu China Academy of Information and Communications Technology Beijing 100191China Beijing Key Laboratory of Work Safety Intelligent Monitoring Department of Electronic EngineeringBeijing University of Posts and TelecommunicationsBeijing 100876China

In this article,novel emulation strategies for the sectored multiple probe anechoic chamber(SMPAC)are proposed to enable the reliable evaluation of the massive multiple-input multiple-output(MIMO)device operating at beamforming mode,which requires a realistic non-stationary channel environment.For the dynamic propagation emulation,an efficient closed-form probe weighting strategy minimizing the power angular spectrum(PAS)emulation errors is derived,substantially reducing the associated computational complexity.On the other hand,a novel probe selection algorithm is proposed to reproduce a more accurate fading environment.Various standard channel models and setup configurations are comprehensively simulated to validate the capacity of the proposed methods.The simulation results show that more competent active probes are selected with the proposed method compared to the conventional algorithms.Furthermore,the derived closedform probe weighting strategy offers identical accuracy to that obtained with complicated numerical optimization.Moreover,a realistic dynamic channel measured in an indoor environment is reconstructed with the developed methodologies,and 95.6%PAS similarity can be achieved with 6 active probes.The satisfactory results demonstrate that the proposed algorithms are suitable for arbitrary channel emulation.

关键词： beamforming channel emulation massive MIMO device multiple probe anechoic chamber(MPAC) over-the-air testing

A multi-level approach to highly efficient recognition of Chinese spam short messages

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Frontiers of Computer Science 2018年第1期12卷 135-145页

作者： Weimin WANG Dan ZHOU School of Computer Science & Engineering Jiangsu University of Science and Technology Jiangsu 212003 China School of Computer and Control Engineering University of Chinese Academy of Sciences Beijing 100190 China

The problem of spam short message （SMS） recognition involves many aspects of natural language pro- cessing. A good solution to solving the problem can not only improve the quality of people experiencing the mobile life, but also has a positive role on promoting the analysis of short text occurring in current mobile applications, such as We- bchat and microblog. As spam SMSes have characteristics of sparsity, transformation and real-timedness, we propose three methods at different levels, i.e., recognition based on sym- bolic features, recognition based on text similarity, and recog- nition based on pattern matching. By combining these meth- ods, we obtain a multi-level approach to spam SMS recog- nition. In order to enrich the pattern base to reduce manual labor and time, we propose a quasi-pattern learning method, which utilizes quasi-pattern matching results in the pattern matching process. The method can learn many interesting and new patterns from the SMS corpus. Finally, a comprehensive analysis indicates that our spare SMS recognition approach achieves a precision rate as high as 95.18%, and a recall rate of 95.51%.

关键词： spam short message spam recognition similar-ity computing pattern learning

Bioprocess inspired formation of calcite mesocrystals by cation-mediated particle attachment mechanism

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National Science Review 2023年第4期10卷 159-168页

作者： Qihang wang Bicheng Yuan Wenyang Huang Hang Ping Jingjing Xie Kun wang Weimin WANG Zhaoyong Zou Zhengyi Fu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Hubei Longzhong Laboratory

Calcite mesocrystals were proposed, and have been widely reported, to form in the presence of polymer additives via oriented assembly of nanoparticles. However, the formation mechanism and the role of polymer additives remain elusive. Here, inspired by the biomineralization process of sea urchin spine comprising magnesium calcite mesocrystals, we show that calcite mesocrystals could also be obtained via atachment of amorphous calcium carbonate(ACC) nanoparticles in the presence of inorganic zinc ions.Moreover, we demonstrate that zinc ions can induce the formation of temporarily stabilized amorphous nanoparticles of less than 20 nm at a significantly lower calcium carbonate concentration as compared to pure solution, which is energetically beneficial for the atachment and occlusion during calcite growth. The cation-mediated particle atachment crystallization significantly improves our understanding of mesocrystal formation mechanisms in biomineralization and offers new opportunities to bioprocess inspired inorganic ions regulated materials fabrication.

关键词： nonclassical crystallization mesocrystal calcium carbonate zinc ion particle attachment

Multi-probe linear fitting and time of arrival linear correction method to analyze blade vibration based on blade tip timing without once-per-revolution

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Chinese Journal of Aeronautics 2023年第1期36卷 290-310页

作者： Sanqun REN Xiaorong XIANG Qingjun ZHAO Weimin WANG Wei ZHAO Chuanlin ZHAN Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China School of Aeronautics and Astronautics University of Chinese Academy of SciencesBeijing 100049China Innovation Academy for Light-duty Gas Turbine Chinese Academy of SciencesBeijing 100190China Beijing University of Chemical Technology Beijing 100029China

Blade vibration monitoring can ensure the safe operation of aeroengine rotor blades.Among the methods of blade vibration monitoring,Blade Tip Timing(BTT)method has attracted more and more attention because of its advantages of non-contact measurement.However,it is difficult to install the Once-Per-Revolution(OPR)probe in the confined space of aeroengine,and the failure and instability of the OPR signal will reduce the reliability of the blade vibration analysis results,which directly affects the accuracy of the blade vibration parameters identification.The Multi-Probe linear fitting and Time of Arrival(ToA)Linear Correction method based on the BTT(MP-LC-BTT)without OPR is proposed to reduce the errors of single probe linear fitting method for blade vibration displacement analysis.The proposed method can also correct the calculation error of blade vibration displacement due to the nonlinear change of rotation speed,which can improve the analysis accuracy of the blade vibration displacement.A new blade vibration model conforming to the actual vibration characteristics is established,and the effectiveness of the proposed method is verified by numerical simulation.Finally,the reliability and accuracy of the MP-LC-BTT method have been verified by the experiments which include two high-speed blade test-benches and an industrial axial fan.This method can be used in the actual aero-engine monitoring instead of the BTT method with OPR.

关键词： Blade Tip Timing(BTT) Linear correction Multi-probe linear fitting Once-Per-Revolution(OPR) Rotor blades Vibration analysis

Strong earthquake clustering around the eastern Tibetan Plateau after the 2008 MW7.9 Wenchuan earthquake

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Science China Earth Sciences 2020年第7期63卷 999-1012页

作者： Duyuan XU Jie XIAO Jiankun HE Weimin WANG Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

After the 2008 M_W7.9 Wenchuan earthquake,the eastern Tibetan Plateau experienced a series of M_W>6.0 earthquakes,including the 2013 M_W6.6 Lushan,2014 M_W6.1 Kangding and 2017 M_W6.5 Jiuzhaigou events.Based on available constraints,we build a three-dimensional viscoelastic finite element model to calculate Coulomb failure stress caused by these strong earthquakes.In this model,the geometry and slip vector of the initial rupture zone of each earthquake are used to better evaluate the earthquake-related stress projection.Considering reasonable ranges of viscosities for the crust and upper mantle in different tectonic units,numerical results show that after the Wenchuan earthquake,the coseismic Coulomb failure stress change at the hypocenters of the subsequent earthquakes increased to approximately+0.012–+0.040,+0.01–+0.03,and+0.008–+0.015 MPa,respectively.With viscoelastic relaxation of the lower crust and upper mantle,the Coulomb failure stress change at the hypocenters of these earthquakes accumulated to about+0.014–+0.042,+0.016–+0.036,and+0.003–+0.007 MPa just before their occurrence.This suggests that the Wenchuan earthquake indeed triggered or hastened the occurrence of the Lushan,Kangding and Jiuzhaigou events,supporting that strong earthquake clustering around the eastern Tibetan Plateau could be related to stress interaction between the seismogenic faults.Besides,~94%and^6%of the stress increase around(and before the occurrence of)the Kangding earthquake were contributed by the Wenchuan event and the Lushan event,respectively;the positive Coulomb failure stress change at the Jiuzhaigou earthquake hypocenter was related to coseismic slip partitioning of the Wenchuan earthquake.This means that stress interaction among the earthquakes could be controlled by the combined effect of stress of the previous events and by the complexity of earthquake ruptures.Thus,in researches on the earthquake-triggering mechanism,special attentions should be paid on both details of the rupture model and multiple factors of prev

关键词： Earthquake clustering Viscoelastic stress triggering Finite element modeling Wenchuan earthquake Eastern Tibetan Plateau

Risk of second primary lung cancer in patients with thyroid cancer:a meta-analysis based on big population studies

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Chinese Medical Journal 2023年第13期136卷 1532-1538页

作者： Haoyu wang Yan wang Ruiyuan Yang Dan Liu weimin Li Department of Respiratory and Critical Care Medicine West China HospitalSichuan UniversityChengduSichuan 610041China Institute of Respiratory Health Frontiers Science Center for Disease-related Molecular NetworkWest China HospitalSichuan UniversityChengduSichuan 610041China Department of Thoracic Surgery West China HospitalSichuan UniversityChengduSichuan 610041China Precision Medicine Center Precision Medicine Key Laboratory of Sichuan ProvinceWest China HospitalSichuan UniversityChengduSichuan 610041China The Research Units of West China Chinese Academy of Medical SciencesWest China HospitalChengduSichuan 610041China

Background:Previous studies have revealed that the number of cancer survivors developing a second primary malignancy is increasing,especially among thyroid cancer patients,and lung cancer is still the main cause of cancer death.Therefore,we aimed to investigate the risk of second primary lung cancer(SPLC)in patients with thyroid cancer.Methods:We searched the PubMed,Web of Science,Embase,and Scopus databases up to November 24,2021,for relevant research and merged the standardized incidence ratios(SIRs)and 95%confidence intervals(95%CIs)to evaluate the risk of developing SPLC in patients with thyroid cancer.Results:Fourteen studies involving 1,480,816 cases were included in our meta-analysis.The pooled result demonstrated that thyroid cancer patients may have a higher risk of SPLC than the general population(SIR=1.21,95%CI:1.07-1.36,P<0.01,I^(2)=81%,P<0.01).Subgroup analysis stratified by sex indicated that female patients may have a markedly higher risk of SPLC than male patients(SIR=1.65,95%CI:1.40-1.94,P<0.01,I^(2)=75%,P<0.01).Conclusions:Thyroid cancer patients are more likely to develop SPLC than the general population,especially women.However,other risk factors must be investigated,and more prospective studies are needed to confirm our results.Registration:International Prospective Register of Systematic Reviews:No.CRD42021285399.

关键词： Second primary lung cancer Thyroid cancer Risk Meta-analysis

Creating Distinctive Connections between Multifunctional Microwave Circuits and Mobile-Terminal Radio-Frequency Integrated Chips Using Integrated Passive Device Technology

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China Communications 2021年第8期18卷 121-132页

作者： Yongle Wu Mengdan Kong Zheng Zhuang Weimin WANG School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

In this review,the advanced microwave devices based on the integrated passive device(IPD)technology are expounded and discussed in detail,involving the performance breakthroughs and circuit innovations.Then,the development trend of IPD-based multifunctional microwave circuits is predicted further by analyzing the current research hot spots.This paper discusses a distinctive research area for microwave circuits and mobile-terminal radio-frequency integrated chips.

关键词： chips integrated passive device(IPD) multifunctional microwave circuit

Exhaust hood performance and its improvement technologies in industrial buildings:A literatu rereview

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Building Simulation 2024年第1期17卷 23-40页

作者： Jing Zhang Jian wang Jun Gao weimin Zhang Architectural Engineering Institute Jinhua PolytechnicJinhua 321017China Institute of HVAC Engineering Schoolof Mechanical EngineeringTongji UniversityShanghai 200092China Tongji Architectural Design(Group)Co .LtdShanghai 200092China

The pollutant control performance of exhaust hoods plays a crucial role in the indoor air quality and energy consumption of ventilation systems in industrial buildings.To better understand the impact of local ventilation on the industrial indoor environment,this paper presents a literature review of exhaust hood performance and its improvement technologies.To create an index for evaluating the performance of exhaust hoods,the capture velocity,capture efficiency,flow ratio of pollutant emissions and exhaust airflow and energy consumption are first introduced.A number of factors affecting exhaust hood performance are assessed such as hood type,hood opening size,exhaust rate,installation distance,pollution source emission and environmental disturbance.Compared to structural improvement methods,the use of active airflow is a more effective way to improve the exhaust hood performance.The most commonly used methods for determining the exhaust rate are the controlled speed method and the flow ratio method.The use of an exhaust hood with an appropriate exhaust rate and jet parameters(for an active air-assisted hood)can effectively improve the pollutant control performance and reduce the energy consumption that would be wasted on the redundant exhaust rate.With more information focused on exhaust hood performance,this work suggests more effective strategies for improving indoor air quality and reducing energy consumption in industrial buildings.

关键词： industrial ventilation exhaust hood capture efficiency exhaust rate performance improvement

Partition-based Network Equivalent Method for Power System Subsynchronous Oscillation Analysis

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 313-320页

作者： Chenxuan wang weimin Zheng Zhen wang Yangqing Dan Ping Ju the Department of Electrical Engineering Zhejiang UniversityHangzhou 310027China the Economic Research Institute of State Grid Zhejiang Electric Power Co. Ltd.Hangzhou 310016China the College of Energy and Electrical Engineering Hohai UniverstiyNanjing 211100China

Given large-scale modern power systems with pow er electronic converters,the numerical simulation with subsyn chronous oscillation(SSO)faces great challenges in engineering practice due to sharply enlarged modeling scale and high com putational burden.To reduce the modeling scale,network parti tion and equivalent becomes a vital technique in numerical sim ulations.Although several methods have been developed for net work equivalent,a generally accepted rule for network parti tion is still required.This paper proposes that the system can be partitioned into three parts,i.e.,the internal,the middle,and the external subsystems,in which the internal subsystem consists of all power electronic components,the middle subsys tem includes those selected AC dynamic components with de tailed models,and the remaining components and buses consti tute the external subsystem.The external subsystem is further represented by an equivalent RLC network determined by the frequency dependent network equivalent(FDNE)method.In the proposed method,the observability index and the electrical distance index are used to identify the interface between the middle and the external subsystems.Case studies based on a modified Hydro-Quebec system are used to verify the effective ness of the proposed method.

关键词： Electrical distance network equivalent subsyn chronous oscillation observability index