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Background Error Covariance Statistics of Hydrometeor Control Variables Based on Gaussian Transform

Advances in Atmospheric Sciences 2021年第5期38卷 831-844页

作者： Tao SUN Yaodeng CHEN deming meng Haiqin CHEN Key Laboratory of Meteorological Disaster of Ministry of Education(KLME)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China

Use of data assimilation to initialize hydrometeors plays a vital role in numerical weather prediction(NWP).To directly analyze hydrometeors in data assimilation systems from cloud-sensitive observations,hydrometeor control variables are *** data assimilation systems theoretically require that the probability density functions(PDFs)of analysis,background,and observation errors should satisfy the Gaussian unbiased *** this study,a Gaussian transform method is proposed to transform hydrometeors to more Gaussian variables,which is modified from the Softmax function and renamed as Quasi-Softmax *** Quasi-Softmax transform method then is compared to the original hydrometeor mixing ratios and their logarithmic transform and Softmax *** spatial distribution,the non-Gaussian nature of the background errors,and the characteristics of the background errors of hydrometeors in each method are *** to the logarithmic and Softmax transform,the Quasi-Softmax method keeps the vertical distribution of the original hydrometeor mixing ratios to the greatest *** results of the D′Agostino test show that the hydrometeors transformed by the Quasi-Softmax method are more Gaussian when compared to the other *** Gaussian transform has been added to the control variable transform to estimate the background error *** show that the characteristics of the hydrometeor background errors are reasonable for the Quasi-Softmax *** transformed hydrometeors using the Quasi-Softmax transform meet the Gaussian unbiased assumptions of the data assimilation system,and are promising control variables for data assimilation systems.

关键词： hydrometeors control variables data assimilation background error covariance Gaussian transform

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Characteristics of Fengyun-4A Satellite Atmospheric Motion Vectors and Their Impacts on Data Assimilation

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Advances in Atmospheric Sciences 2020年第11期37卷 1222-1238页

作者： Yaodeng CHEN Jie SHEN Shuiyong FAN deming meng Cheng WANG Key Laboratory of Meteorological Disaster of Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China

The high observation efficiency,scanning speed and observation frequency of the Fengyun-4A(FY-4A)satellite indicates the progress of Chinese geostationary meteorological *** characteristics of FY-4A atmospheric motion vectors(AMVs)derived from the high-level water vapor(WV-High)channel,mid-level water vapor(WV-Mid)channel,and infrared(IR)channel of FY-4A are analyzed,and their corresponding observation errors ***,the impacts of single-channel and multi-channel FY-4A AMVs on RMAPS-ST(the Rapid-refresh Multi-scale Analysis and Prediction System-Short Term)are evaluated based on one-month data assimilation cycling and forecasting *** show that the observation errors of FY-4A AMVs from the three channels have an explicit vertical *** from the cycling experiments indicate that the assimilation of AMVs from WV-High produces more apparent improvement of the wind in the upper layer,while a more positive effect in the lower layer is achieved by the assimilation of AMVs from ***,the assimilation of AMVs from IR is more skillful for medium and moderate precipitation than from other channels owing to the good quality of data in the lower layer in the AMVs from *** of FY-4A AMVs from the three channels could combine the advantages of assimilation from each individual channel to improve the wind in the upper,middle and lower layers simultaneously.

关键词： data assimilation FY-4A satellite atmospheric motion vector observation error

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Variational Assimilation of Satellite Cloud Water/Ice Path and Microphysics Scheme Sensitivity to the Assimilation of a Rainfall Case

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Advances in Atmospheric Sciences 2016年第10期33卷 1158-1170页

作者： Yaodeng CHEN Ruizhi ZHANG deming meng Jinzhong MIN Lina ZHANG Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China China Meteorological Administration Training Center Beijing 100081China

Hydrometeor variables （cloud water and cloud ice mixing ratios） are added into the WRF three-dimensional variational assimilation system as additional control variables to directly analyze hydrometeors by assimilating cloud observations. In addition, the background error covariance matrix of hydrometeors is modeled through a control variable transform, and its characteristics discussed in detail. A suite of experiments using four microphysics schemes （LIN, SBU-YLIN, WDM6 and WSM6） are performed with and without assimilating satellite cloud liquid/ice water path. We find analysis of hydrometeors with cloud assimilation to be significantly improved, and the increment and distribution of hydrometeors are consistent with the characteristics of background error covariance. Diagnostic results suggest that the forecast with cloud assimilation represents a significant improvement, especially the ability to forecast precipitation in the first seven hours. It is also found that the largest improvement occurs in the experiment using the WDM6 scheme, since the assimilated cloud information can sustain for longer in this scheme. The least improvement, meanwhile, appears in the experiment using the SBU-YLIN scheme.

关键词： variational data assimilation cloud microphysics scheme satellite

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Assimilation of FY-3D MWTS-Ⅱ Radiance with 3D Precipitation Detection and the Impacts on Typhoon Forecasts

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Advances in Atmospheric Sciences 2023年第5期40卷 900-919页

作者： Luyao QIN Yaodeng CHEN Gang MA Fuzhong WENG deming meng Peng ZHANG Key Laboratory of Meteorological Disaster of Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjing 210044China Earth System Modeling and Prediction Centre China Meteorological AdministrationBeijing 100081China Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites(LRCVES/CMA) National Satellite Meteorological CenterChina Meteorological Administration(NSMC/CMA)Beijing 100081China

Precipitation detection is an essential step in radiance assimilation because the uncertainties in precipitation would affect the radiative transfer calculation and observation *** traditional precipitation detection method for microwave only detects clouds and precipitation horizontally,without considering the three-dimensional distribution of *** precipitation detection from 2D to 3D is expected to bring more useful information to the data assimilation without using the all-sky *** this study,the 3D precipitation detection method is adopted to assimilate Microwave Temperature Sounder-2(MWTS-Ⅱ)onboard the Fengyun-3D,which can dynamically detect the channels above precipitating clouds by considering the near-real-time cloud *** data assimilation and forecasting experiments for Typhoons Lekima(2019)and Mitag(2019)are carried *** with the control experiment,the quantity of assimilated data with the 3D precipitation detection increases by approximately 23%.The quality of the additional MWTS-Ⅱradiance data is close to the clear-sky *** case studies show that the average root-mean-square errors(RMSE)of prognostic variables are reduced by 1.7%in the upper troposphere,leading to an average reduction of4.53%in typhoon track *** detailed diagnoses of Typhoon Lekima(2019)further show that the additional MWTS-Ⅱradiances brought by the 3D precipitation detection facilitate portraying a more reasonable circulation situation,thus providing more precise *** paper preliminarily proves that 3D precipitation detection has potential added value for increasing satellite data utilization and improving typhoon forecasts.

关键词： numerical weather prediction radiance assimilation microwave temperature sounding FY-3D MWTS-II precipitation detection

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Nest-type NCM ■ Pt/C with oxygen capture character as advanced electrocatalyst for oxygen reduction reaction

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Journal of Energy Chemistry 2022年第8期31卷 304-312,I0009页

作者： Teng Chen Yida Xu deming meng Xuefeng Guo Yan Zhu Luming Peng Jianqiang Hu Weiping Ding Key Lab of Mesoscopic Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023JiangsuChina Department of Aviation Oil and Material Air Force Logistics AcademyXuzhou 221000Jiangsu.China

A unique nest-type catalyst has been designed with a nest of oxygen capture surrounding catalytic Pt centers, which shows much promoted performance, on the base of Pt/C catalyst, for oxygen reduction reaction(ORR). The nest is constructed with nitrogen-doped carbon matrix(NCM), derived from the controlled carbonization of PANI precursor, to cover Pt/C catalyst. The unique structure of the catalyst(denoted as NCM■ Pt/C) has many merits. Firstly, it can capture oxygen both in air and in acidic electrolyte. Compared with naked Pt/C, it is found that, in air, the oxygen concentration within the porous nest of NCM surrounding Pt/C particles is ~13 times higher than atmospheric oxygen concentration and, in acidic electrolyte, the concentration of activated oxygen over the catalyst NCM■ Pt/C rise to~1.9 times. Secondly, the NCM nest offers a special electronic modulation on Pt centers toward modified ORR kinetics and then catalytic performances. With these merits, compared with Pt/C, the NCM■ Pt/C catalyst shows 3.2 times higher turnover frequency value and 2.9 times enhanced specific activity for ORR with half-wave potential at 0.894 V. After 50,000 sweeping cycles, the NCM■ Pt/C catalyst retains~66% mass activity and still has advantages over the fresh Pt/C catalyst. We envision that the nest-type catalyst provides a new idea for progress of practical Pt/C ORR catalyst.

关键词： Oxygen reduction reaction Surrounding environment Nest-type catalyst Oxygen capture Electronic modulation

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A Cooperated Imperialist Competitive Algorithm for Unrelated Parallel Batch Machine Scheduling Problem

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Computers, Materials & Continua 2024年第5期79卷 1855-1874页

作者： deming Lei Heen Li College of Automation Wuhan University of TechnologyWuhan430070China

This study focuses on the scheduling problem of unrelated parallel batch processing machines(BPM)with release times,a scenario derived from the moulding process in a *** this process,a batch is initially formed,placed in a sandbox,and then the sandbox is positioned on a BPM *** complexity of the scheduling problem increases due to the consideration of BPM capacity and sandbox *** minimize the makespan,a new cooperated imperialist competitive algorithm(CICA)is *** CICA,the number of empires is not a parameter,and four empires aremaintained throughout the search *** types of assimilations are achieved:The strongest and weakest empires cooperate in their assimilation,while the remaining two empires,having a close normalization total cost,combine in their assimilation.A new form of imperialist competition is proposed to prevent insufficient competition,and the unique features of the problem are effectively *** experiments are conducted across several instances,and a significant amount of experimental results show that the newstrategies of CICAare effective,indicating promising advantages for the considered BPMscheduling problems.

关键词： Release time assimilation imperialist competitive algorithm batch processing machines scheduling

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Swimming velocity of spherical squirmers in a square tube at finite fluid inertia

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1481-1498页

作者： Tongxiao JIANG deming NIE Jianzhong LIN Institute of Fluid Mechanics China Jiliang UniversityHangzhou 310008China Key Laboratory of Impact and Safety Engineering(Ningbo University) Ministry of EducationNingbo 315211China Institute of Fluid Engineering Zhejiang UniversityHangzhou 310027China

The three-dimensional lattice Boltzmann method(LBM)is used to simulate the motion of a spherical squirmer in a square tube,and the steady motion velocity of a squirmer with different Reynolds numbers(Re,ranging from 0.1 to 2)and swimming types is investigated and analyzed to better understand the swimming characteristics of microorganisms in different ***,as the Reynolds number increases,the effect of the inertial forces becomes significant,disrupting the squirmer's ability to maintain its theoretical ***,as the Reynolds number increases,the structure of the flow field around the squirmer changes,affecting its velocity of ***,the swimming velocity of the squirmer exhibits a quadratic relationship with the type of swimming and the Reynolds ***,the narrow tube exerts a significant inhibitory effect on the squirmer *** addition,although chirality does not directly affect the swimming velocity of the squirmer,it can indirectly affect the velocity by changing its motion mode.

关键词： spherical squirmer swimming characteristics swimming velocity fow structure

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An Elite-Class Teaching-Learning-Based Optimization for Reentrant Hybrid Flow Shop Scheduling with Bottleneck Stage

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Computers, Materials & Continua 2024年第4期79卷 47-63页

作者： deming Lei Surui Duan Mingbo Li Jing Wang College of Automation Wuhan University of TechnologyWuhan430070China

Bottleneck stage and reentrance often exist in real-life manufacturing processes;however,the previous research rarely addresses these two processing conditions in a scheduling *** this study,a reentrant hybrid flow shop scheduling problem(RHFSP)with a bottleneck stage is considered,and an elite-class teaching-learning-based optimization(ETLBO)algorithm is proposed to minimize maximum completion *** produce high-quality solutions,teachers are divided into formal ones and substitute ones,and multiple classes are *** teacher phase is composed of teacher competition and teacher *** learner phase is replaced with a reinforcement search of the elite *** adjustment on teachers and classes is established based on class quality,which is determined by the number of elite solutions in *** experimental results demonstrate the effectiveness of new strategies,and ETLBO has a significant advantage in solving the considered RHFSP.

关键词： Hybrid flow shop scheduling reentrant bottleneck stage teaching-learning-based optimization

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Design of Low-Power Turbo Encoder and Decoder for NB-IoT

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Chinese Journal of Electronics 2024年第2期33卷 403-414页

作者： Chong ZHANG Yuhang LIN deming WANG Jianguo HU School of Microelectronics Science and Technology Sun Yat-sen University School of Physics and Telecommunication Engineering South China Normal University School of Electronics and Information Engineering South China Normal University Development Research Institute of Guangzhou Smart City Shenzhen Research Institute of Sun Yat-sen University

Turbo code is an error correction coding scheme close to the Shannon limit, usually used in wireless data transmission. Based on the parallel Turbo code algorithm, a parallel Turbo code circuit design scheme is *** the encoder, the recursive systematic convolutional encoder is multiplexed. The decoder is divided into branch metric, recursive, maximum likelihood ratio, and external information calculation modules. The decoding algorithm is based on Max-Log-MAP, controlling the component decoder in parallel. And the state metric calculation in the decoding circuit is combined to reduce the overall power consumption effectively, enabling the encoder and decoder to be used in narrowband Internet of things(NB-IoT). Finally, the hardware scheme of the main functional modules of Turbo code encoding and decoding is designed and implemented. The results show that the dynamic power consumption is less than 50 m W. The overall on-chip power consumption is reduced by 40% at the frequency of 125 MHz compared with previous jobs.

关键词： Measurement Wireless communication Power demand Systematics Turbo codes System-on-chip Power dissipation

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Overhead-free Noise-tolerant Federated Learning: A New Baseline

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Machine Intelligence Research 2024年第3期21卷 526-537页

作者： Shiyi Lin deming Zhai Feilong Zhang Junjun Jiang Xianming Liu Xiangyang Ji Department of Computer Science and Technology Harbin Institute of TechnologyHarbin150000China Department of Automation Tsinghua UniversityBeijing100084China

Federated learning (FL) is a promising decentralized machine learning approach that enables multiple distributed clients to train a model jointly while keeping their data private. However, in real-world scenarios, the supervised training data stored in local clients inevitably suffer from imperfect annotations, resulting in subjective, inconsistent and biased labels. These noisy labels can harm the collaborative aggregation process of FL by inducing inconsistent decision boundaries. Unfortunately, few attempts have been made towards noise-tolerant federated learning, with most of them relying on the strategy of transmitting overhead messages to assist noisy labels detection and correction, which increases the communication burden as well as privacy risks. In this paper, we propose a simple yet effective method for noise-tolerant FL based on the well-established co-training framework. Our method leverages the inherent discrepancy in the learning ability of the local and global models in FL, which can be regarded as two complementary views. By iteratively exchanging samples with their high confident predictions, the two models “teach each other” to suppress the influence of noisy labels. The proposed scheme enjoys the benefit of overhead cost-free and can serve as a robust and efficient baseline for noise-tolerant federated learning. Experimental results demonstrate that our method outperforms existing approaches, highlighting the superiority of our method.

关键词： Federated learning noise-label learning privacy-preserving machine learning edge intelligence distributed machine learning

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