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The Relationship between Deterministic and Ensemble Mean Forecast Errors Revealed by Global and Local Attractor Radii

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Advances in Atmospheric sciences 2019年第3期36卷 271-278,339页

作者： Jie FENG Jianping LI Jing ZHANG Deqiang LIU Ruiqiang DING School of Meteorology University of Oklahoma College of Global Change and Earth System Science (GCESS) Beijing Normal University Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology Cooperative Institute for Research in the Atmosphere GSD/ESRL/OAR/NOAA Fujian Meteorological Observatory Wuyishan National Park Meteorological Observatory State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology

It has been demonstrated that ensemble mean forecasts, in the context of the sample mean, have higher forecasting skill than deterministic(or single) forecasts. However, few studies have focused on quantifying the relationship between their forecast errors, especially in individual prediction cases. Clarification of the characteristics of deterministic and ensemble mean forecasts from the perspective of attractors of dynamical systems has also rarely been involved. In this paper, two attractor statistics—namely, the global and local attractor radii(GAR and LAR, respectively)—are applied to reveal the relationship between deterministic and ensemble mean forecast errors. The practical forecast experiments are implemented in a perfect model scenario with the Lorenz96 model as the numerical results for verification. The sample mean errors of deterministic and ensemble mean forecasts can be expressed by GAR and LAR, respectively, and their ratio is found to approach2^(1/2) with lead time. Meanwhile, the LAR can provide the expected ratio of the ensemble mean and deterministic forecast errors in individual cases.

关键词： attractor radius ensemble forecasting ensemble mean forecast error saturation

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Study of RF structure and Beam Wave Interaction system for a W-band Sheet Beam EIK

Study of RF structure and Beam Wave Interaction system for a...

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International Conference on Radar Systems

作者： Shuyuan Chen Jiaqi Liu Lu Gao Jinliang Bai Zhiye Jiang Feng Xu Peng Qin Hongyan Liu Xin Liu Hu Li Jingpeng Gao National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing 100076 P. R. China

ISBN: (纸本)9781785616723

Sheet beam Extended Interaction Klystron (EIK) is an attractive Millimeter Waves (MMW) amplifier because of its high gain per unit length and compact configuration, which can be used in radar transmission system. In this paper, RF structure and beam wave interaction system of W band sheet beam EIK has been designed. A new and effective method of designing and studying the beam wave interaction system is presented in this paper. The whole tube consists of one single-gap cavity, six tri-gaps cavities and one five-gaps cavity. By optimizing the position of cavities, the output power can achieve 30 kW and high gain of 50 dB, which is calculated by three dimensional particle in cell (3D-PIC) software. It provides a powerful basis for the subsequent study of sheet beam EIK.

关键词： RF EIK Dumbbell cavity Interaction system

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A MULTI-AGENT JAMMING DECISION-MAKING METHOD BASED ON SP-HASAC

A MULTI-AGENT JAMMING DECISION-MAKING METHOD BASED ON SP-HAS...

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IET International Radar Conference 2023, IRC 2023

作者： Gao, Jingpeng Shen, Chen Gao, Lu Jiang, Zhiye College of Information and Communication Engineering Harbin Engineering University Harbin China Beijing Institute of Electronic System Engineering Beijing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

ISBN: (纸本)9781839539954

In the study of the multi-UAV penetration mission decision method, the Heterogeneous Agent Soft Actor-Critic algorithm uses the HAML framework and the maximum entropy principle to enable UAVs to have stronger anti-jamming capability and exploration capability. However, it is difficult to accurately evaluate the action value of UAVs and the training stability is poor. To address this issue, this paper proposes a multi-agent based on the state prediction-HASAC(SP-HASAC) jamming decision method. Based on the idea of advantage function decomposition and environmental dynamics model, the state prediction network is designed to extract more abundant spatial information of penetration battlefield and achieve accurate evaluation of the action value of multi-UAV. Combining with the negative domain activation theory, the ReLU function is improved to realize the stable training of multi-UAV. The simulation results show that in the electronic penetration scenario of three UAVs against a single radar, the training convergence time of the proposed improved algorithm is reduced by 22% compared with the original algorithm. Three UAVs penetration to twice the burn-through distance still has more than 70% penetration success rate. © The Institution of Engineering & technology 2023.

关键词： Jamming

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Factors contributing to rapid decline of Arctic sea ice in autumn

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Advances in Polar science 2021年第2期32卷 96-104页

作者： LI Shuyao CUI Hongyan XU Junli GONG Xiang QIAO Fangli YANG Yanzhao WANG Ping HAN Yuqun SHAN Feng College of Mathematics and Physics Qingdao University of Science and TechnologyQingdao 266061China Research Institute for Mathematics and Interdisciplinary Sciences Qingdao University of Science and TechnologyQingdao 266061China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and TechnologyQingdao 266061China The First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China

Autumn Arctic sea ice has been declining since the beginning of the era of satellite sea ice *** this study,we examined the factors contributing to the decline of autumn sea ice *** the Beaufort Sea to the Barents Sea,autumn sea ice concentration has decreased considerably between 1982 and 2020,and the rates of decline were the highest around the Beaufort *** calculated the correlation coefficients between sea ice extent(SIE)anomalies and anomalies of sea surface temperature(SST),surface air temperature(SAT)and specific humidity(SH).Among these coefficients,the largest absolute value was found in the coefficient between SIE and SAT anomalies for August to October,which has a value of−*** second largest absolute value was found in the coefficient between SIE and SH anomalies for September to November,which has a value of−*** the correlation coefficients between SIE and SST anomalies,the largest absolute value was found in the coefficient for August to October,which has a value of−*** conducted empirical orthogonal function(EOF)analyses of sea ice,SST,SAT,SH,sea level pressure(SLP)and the wind field for the months where the absolute values of the correlation coefficient were the *** first EOFs of SST,SAT and SH account for 39.07%,63.54%and 47.60%of the total variances,respectively,and are mainly concentrated in the area between the Beaufort Sea and the East Siberian *** corresponding principal component time series also indicate positive *** first EOF of SLP explains 41.57%of the total *** is mostly negative in the central *** the Beaufort,Chukchi and East Siberian seas,the zonal wind weakened while the meridional wind *** from the correlation and EOF analyses further verified the effects of the ice-temperature,ice-SH and ice-SLP feedback mechanisms in the *** mechanisms accelerate melting and decrease the rate of formation of sea *** addition,stronger m

关键词： Arctic sea ice rapid decline empirical orthogonal function feedback mechanisms

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Preliminary analysis of echolocation signals produced by fleeing Irrawaddy dolphins(Orcaella brevirostris)

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Acta Oceanologica Sinica 2019年第1期38卷 85-89页

作者： Ying Jiang Xuelei Zhang Zhiguo Yang Saifullah Arifin Jaaman Qinzeng Xu Azmi Marzuki Muda Hairul Masrini Muhamad First Institute of Oceanography Ministry of Natural Resources Laboratory for Regional Oceanography and Numerical Modeling Pilot National Laboratory for Marine Science and Technology (Qingdao) Laboratory for Marine Ecology and Environmental Science Pilot National Laboratory for Marine Science and Technology (Qingdao) China National Deep Sea Center Ministry of Natural Resources Institute of Oceanography & Environment University Malaysia Terengganu Key Laboratory of Underwater Acoustics and Marine Information Technology Department of Applied Marine Physics & Engineering College of Ocean and Earth Xiamen University

In this study, echolocation signals were recorded from a wild Irrawaddy dolphin(Orcaella brevirostris) in shallow water in the Bay of Brunei. During sound recording, a small fishing boat engine startled a nearby Irrawaddy dolphin and began chasing it on two occasions. Variations in the acoustic parameters were detected. When the Irrawaddy dolphin was startled and chased, the sound pressure level, number of click trains per minute, pulse number, and average inter-pulse interval(PI) per click train were all affected. The PI increased and exhibited a slight downward trend during the chase. The increase in PI indicated an increase in the inspection distance as the dolphin escaped. Thus, Irrawaddy dolphins may adapt their echolocation signals to stand out from ambient noise in the wild and to improve their search efforts in potentially risky situations. Appropriate management of the burst noise around the dolphins is important.

关键词： click train echolocation signal Irrawaddy dolphin signal change

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Study of RF structure for W band sheet beam EIK

Study of RF structure for W band sheet beam EIK

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IET International Radar Conference 2015

作者： Shuyuan Chen Zhiye Jiang Jiaqi Liu Lu Gao Jingliang Bai Hongyan Liu Gang Meng Feng Xu Hu Li Chengguo Liu Guangsheng Zhu National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing 100076 P. R. China

Microwave tubes are vacuum electron devices used for the generation and amplification of radio frequencies in the microwave frequency range. Klystron is a kind of microwave tubes which is used in radar. A sheet-beam Extended Interaction Klystron (SBEIK) is an attractive MMW amplifier because of its high gain per unit length and compact configuration. The RF structure is an important part of the whole tube, which is used for beam wave interaction. In this paper, two kinds of barbell cavity has been studied. The difference between the separating multi-gap barbell resonant cavity and the strong coupling multi-gap barbell cavity has been discussed. RF parameters have been calculated by 3D simulations.

关键词： EIK Klystron Microwave RF barbell cavity radiofrequency MICROWAVE microwave tubes Barbells Klystrons Electron devices high gain

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Adaptive feed-forward control for seeker based on the disturbance observer

Adaptive feed-forward control for seeker based on the distur...

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IEEE Advanced Information technology, Electronic and Automation Control Conference (IAEAC)

作者： Xin Liu Zhenhong Niu Yi Shu Lian Xue Mingchao Zhu National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences

In order to improve the tracking and stabilization performance, a control method combining disturbance observer and adaptive feed-forward control using parameterization is proposed for seeker stabilized platforms. The system identification algorithm is used to identify dynamic model of the true plant. Then the discrete-time disturbance observer is designed. The feedback loop controller is designed using pole-placement techniques. The recursive least square (RLS) adaptive filter is used to build the inverse model of the feedback control loop and in this way, the feed-forward control is constructed. The adaptive filter and the feedback loop constitute a control scheme with two degrees-of-freedom (DOF). Tracking experiments conducted on velocity command inputs verify the validity of the adaptive feed-forward controller. Experimental results show that this method responses quickly to commands. For a sinusoidal signal at the frequency of 30Hz, the adaptive feed-forward controller can obtain an amplitude response without attenuation and the phase lag is reduced to 11° in contrast with the feedback control whose phase lag is 60°. This method significantly improves the transient performance and is superior to the feedback control alone.

关键词： Adaptive filters Feedback control Disturbance observers Feedforward systems Low pass filters Tracking loops Stability analysis

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Summer Persistence Barrier of Sea Surface Temperature Anomalies in the Central Western North Pacific

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Advances in Atmospheric sciences 2012年第6期29卷 1159-1173页

作者：赵霞李建平张文君 Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Science State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of Sciences Key Laboratory of Meteorological Disaster of Ministry of Education and College of Atmospheric Sciences Nanjing University of Information Science and Technology

The persistence barrier of sea surface temperature anomalies （SSTAs） in the North Pacific was investigated and compared with the ENSO spring persistence barrier. The results show that SSTAs in the central western North Pacific （CWNP） have a persistence barrier in summer： the persistence of SSTAs in the CWNP shows a significant decline in summer regardless of the starting month. Mechanisms of the summer persistence barrier in the CWNP are different from those of the spring persistence barrier of SSTAs in the central and eastern equatorial Pacific. The phase locking of SSTAs to the annual cycle does not explain the CWNP summer persistence barrier. Remote ENSO forcing has little linear influence on the CWNP summer persistence barrier, compared with local upper-ocean process and atmospheric forcing in the North Pacific. Starting in wintertime, SSTAs extend down to the deep winter mixed layer then become sequestered beneath the shallow summer mixed layer, which is decoupled from the surface layer. Thus, wintertime SSTAs do not persist through the following summer. Starting in summertime, persistence of summer SSTAs until autumn can be explained by the atmospheric forcing through a positive SSTAs-cloud/radiation feedback mechanism because the shallow summertime mixed layer is decoupled from the temperature anomalies at depth, then the following autumnwinter-spring, SSTAs persist. Thus, summer SSTAs in the CWNP have a long persistence, showing a significant decline in the following summer. In this way, SSTAs in the CWNP show a persistence barrier in summer regardless of the starting month.

关键词： SST anomalies persistence barrier oceanic mixed layer atmospheric forcing positive cloudfeedback on SSTAs

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A Jamming Decision-Making Method Based on Next State Prediction SAC 6

A Jamming Decision-Making Method Based on Next State Predict...

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6th IEEE International Conference on Electronic Information and Communication technology, ICEICT 2023

作者： Chen, Geng Gao, Jingpeng Zhang, Tianran Jiang, Zhiye Shen, Chen College of Information and Communication Engineering Harbin Engineering University Harbin China Beijing Institute of Electronic System Engineering Beijing100854 China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (纸本)9798350399059

In light of the growing complexity of the electromagnetic environment, traditional jamming decision-making methods have become less effective due to poor generalization and inefficient jamming performance. This paper proposes a jamming decision-making method based on next state prediction SAC (Soft Actor-Critic) to address this issue. Firstly, we design the state, action, and reward elements under electronic warfare scenarios. Secondly, a next state prediction critic network is proposed to accurately estimate the value function by modeling the environment dynamics and extracting richer representational information. Finally, a negative activation ReLU is introduced to improve the utilization ratio of network parameters. Simulation results show that the proposed method achieves a 98.4% success rate at a distance of 90 km from the radar and a 70.0% success rate at 30 km. Therefore, this method exhibits good adaptability and jamming performance in the field of jamming decision-making. © 2023 IEEE.

关键词： Decision making

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A novel non-enzymatic hydrogen peroxide sensor based on Co:ZnO modified electrodes

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Progress in Natural science:Materials International 2018年第1期28卷 24-27页

作者： Long Wang Tong Wu Han Wu Jun Zhong Ning Wang Rongming Wang Department of Equipment Manufacture Zhongshan Torch Polytechnic National Institute of Metrology China National Computer Products Quality Supervising Test Center Beijing Key Laboratory for Carbon-Based Functional Materials and Devices Institute of Functional Nano and Soft Materials Laboratory (FUNSOM) Soochow University Center for Green Innovation School of Mathematics and Physics University of Science and Technology Beijing

There is currently intense interest in the use of nanoparticles for a wide range of biomedical and technological applications. In this paper, the hierarchical Co doped ZnO nanoflowers were synthesized by a facile wet chemical method and explored as biosensing material. The as-modified novel hydrogen peroxide sensor exhibited a wide linear range（0.25–20 mM）, highly reproducible response（R.S.D. of 2.7%） and long-term stability. The doping Co2+ions carried out the oxidations rapidly and efficiently for the catalysis of hydrogen peroxide（H2O2）. A high activity toward H2O2in the presence of ascorbic acid（AA） and NaNO2, which are only common for natural enzymes, has also been demonstrated. The good analytical performance, low cost and straightforward preparation method makes this doped semiconductor promising for a wide range of potential applications in medicine, biotechnology and environmental chemistry.

关键词： Nonenzymatic H2O2 sensor Co:ZnO Nanoflowers Electrocatalysis

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