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Viscous Rayleigh-Taylor instability with and without diffusion effect

Applied Mathematics and Mechanics(English Edition) 2017年第2期38卷 263-270页

作者： Chenyue XIE Jianjun TAO Ji LI Center for Applied Physics and Technology (CAPT)-MOE Key Laboratory of High Energy Density Physics Simulation (HEDPS) State Key Laboratory for Turbulence and Complex System (SKLTCS) Department of Mechanics and Engineering ScienceCollege of Engineering Peking University Department of Engineering University of Cambridge

The approximate but analytical solution of the viscous Rayleigh-Taylor insta- bility （RTI） has been widely used recently in theoretical and numerical investigations due to its clarity. In this paper, a modified analytical solution of the growth rate for the viscous RTI of incompressible fluids is obtained based on an approximate method. Its accuracy is verified numerically to be significantly improved in comparison with the previous one in the whole wave number range for different viscosity ratios and Atwood numbers. Fur- thermore, this solution is expanded for viscous RTI including the concentration-diffusion effect.

关键词： viscous Rayleigh-Taylor instability （RTI） dispersion relation diffusioneffect

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Effectiveness Evaluation of Reconnaissance Satellite system based on Analytic Hierarchy Process and Cloud Model 5

Effectiveness Evaluation of Reconnaissance Satellite System ...

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5th IEEE Information technology, Networking, electronic and Automation Control Conference, ITNEC 2021

作者： Han, Chi Xiong, Wei Xiong, Minghui Liu, Zhen Liu, Wenwen Yu, Xiaolan Jian, Ping Space Engineering University Aerospace Information Institute Beijing China Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing China

ISBN: (纸本)9781665415989

Considering the complexity of effectiveness evaluation index of reconnaissance satellite system (RSS), the cloud model theory and AHP method are combined. A fuzzy evaluation method of combat effectiveness based on cloud model is proposed. A multi-layer evaluation index system is constructed through the AHP method, and the weight of each level index is calculated. Combining the multi-dimensional cloud model with the AHP method, a quantitative fuzzy evaluation method for qualitative indicators and quantitative data is designed, and the qualitative evaluation results are obtained. The experimental results show that the proposed evaluation method can effectively realize the fuzzy quantitative evaluation under the complex evaluation index system with good performance in terms of calculation accuracy and fuzziness. © 2021 IEEE.

关键词： Analytic hierarchy process

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Research on flame classification and recognition based on object detection and similarity fusion

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The Journal of China Universities of Posts and Telecommunications 2021年第5期28卷 59-67页

作者： He Xin Zhou Junhua Liao Zhonghua Zhai Xiang Sun Siyuan School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Beijing Complex Product Advanced Manufacturing Engineering Research Center Beijing Simulation CenterBeijing 100854China State Key Laboratory of Intelligent Manufacturing System Technology Beijing Institute of Electronic System EngineeringBeijing 100854China

The color, shape, and other appearance characteristics of the flame emitted by different flame engines are different. In order to make a preliminary judgment on the category of the device to which it belongs through studying exterior characteristics of the flame, this paper uses the flame of matches, lighters, and candles to simulate different types of flames. It is hoped that the flames can be located and classified by detecting the characteristics of flames using the object detection algorithm. First, different types of fire are collected for the dataset of experiments. The mmDetection toolbox is then used to build several different object detection frameworks, in which the dataset can be trained and tested. The object detection model suitable for this kind of problem is obtained through the evaluation index analysis. The model is ResNet50-based faster-region-convolutional neural network(Faster R-CNN), whose mean average-precision(mAP) is 93.6%. Besides, after clipping the detected flames through object detection, a similarity fusion algorithm is used to aggregate and classify the three types of flames. Finally, the color components are analyzed to obtain the red, green, blue(RGB) color histograms of the three flames.

关键词： flame classification object detection similarity fusion

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A Multi-objective optimization model for simulation-based acquisition 7

A Multi-objective optimization model for simulation-based ac...

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7th IEEE International Conference on Progress in Informatics and Computing, PIC 2020

作者： Zhang, Xue Xue, Junjie Zhou, Junhua Shi, Guoqiang Yu, Yan Nanjing University of Science and Technology School of Computer Science and Engineering Nanjing China Beijing Simulation Center Beijing Complex Product Advanced Manufacturing Engineering Research Center Beijing China State Key Laboratory of Intelligent Manufacturing System Technology Beijing Institute of Electronic System Engineering Beijing China Science and Technology on Space System Simulation Laboratory Beijing Simulation Center Beijing China

ISBN: (纸本)9781728170862

Large-scale equipment presents the characteristics of technology-intensive, knowledge-intensive and complex, which brings high investment and high risk to equipment acquisition. This paper analyzes the various components of equipment acquisition to fully apply modeling and simulation technology to each stage of it. On the basis of multi-objective optimization theory, the objective function of the lowest risk and lowest cost of simulation-based acquisition (SBA) is proposed. Then establishing a multi-objective optimization model for simulation-based acquisition according to the corresponding constraints. The nondominated sorting genetic algorithm II (NSGA II) and multi-objective particle swarm optimization (MOPSO) algorithms are used to optimize the model, and the majority voting method is used for integration. The comparison of simulation examples proves that the multi-objective optimization model oriented to SBA designed in this paper can effectively realize the optimization of each objective of SBA under cost constraints. And the feasibility and efficiency of optimization solution are guaranteed. © 2020 IEEE.

关键词： Multiobjective optimization

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Innovative design of cassegrain solar concentrator system for indoor illumination utilizing chromatic aberration to filter out ultraviolet and infrared in sunlight

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Solar Energy 2009年第8期83卷 1115-1122页

作者： Whang, Allen Jong-Woei Chen, Yi-Yung Wu, Bo-Yi Photonics System Simulation Design Laboratory Department of Electronic Engineering National Taiwan University of Science and Technology 43 Sec.4 Keelung Rd Taipei 106 Taiwan

Many applications and related studies of solar energy have been focused on guiding sunlight into the indoors for illumination purposes. To achieve this objective, one of the approaches is the use of a high efficiency solar concentrator based on cassegrain construction with sun tracking system. However, exposure to UV in sunlight has been proved to be hazardous to humans, and the heat content of IR degrades illumination quality. In order to solve the two problems, we develop an innovative cassegrain solar concentrator system utilizing the theory of chromatic aberration by a chromatic lens to reduce UV and IR. A dispersion model to consider the impact between the chromatic lens and a guiding fiber is also proposed. As a result, the system can filter out UV completely and reduce IR by half. Further, the chromaticity coordinates of collected light for illumination is almost equal to sunlight, and the color difference is so small that the two appear equal to the human eye. © 2009.

关键词： Solar concentrators

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The way to analysis of spatial association

The way to analysis of spatial association

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2013 International Conference on Vehicle and Mechanical Engineering and Information technology, VMEIT 2013

作者： Guo, Jing Liu, De Sheng Guo, Qin Science and Technology on Complex Electronic System Simulation Laboratory The Academy of Equipment Huairou Beijing China School of Humanities and Social Sciences National University of Defense Technology Changsha Hunan China

ISBN: (纸本)9783037858202

Following the continual development and maturation of the technology of association analysis, it can be used to mine the relation between spatial data. The paper introduced definition and classification of association analysis technology. It analyses the spatial Association from physics layer, link layer and act layer. Based on above, it provides the process of association analysis about spatial data. © (2013) Trans Tech Publications, Switzerland.

关键词： Data mining

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Research on hall for workshop of meta-synthetic engineering for demonstration on weapon equipment system of system

Research on hall for workshop of meta-synthetic engineering ...

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3rd International Conference on Materials science and Information technology, MSIT 2013

ISBN: (纸本)9783037857700

Aimed to the complexity of and weapon equipment 'system of system'(SoS) and demonstration process, we demonstrated the building needs of hall for workshop of meta-synthetic engineering(HWME) for demonstration on weapon equipment SoS from the angle of function and application. Based on the process of demonstration, the framework of HWME for demonstration of weapon equipment system was built. Based on the mechanism of message transferring, arithmetic and mutual ability, the discussion system of weapon equipment SoS was designed by intelligent decision, group decision, parallel engineering. At last, the paper gave the mutual relation on each composing of the discussion system. © (2013) Trans Tech Publications, Switzerland.

关键词： Demonstrations

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Study on photoelectric anti-interference technology of Optical Detecting system used in Surface-to-air Missiles 6

Study on photoelectric anti-interference technology of Optic...

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6th Conference on Frontiers in Optical Imaging and technology: Imaging Detection and Target Recognition

作者： Li-Qin, Zhang Lei, Chen Wei, Shen Jin-Dong, Fei Beijing Institute of Electronic System Engineering Peking100854 China Science and Technology on Special System Simulation Laboratory Peking100854 China

ISBN: (数字)9781510679733

ISBN: (纸本)9781510679726

As the battlefield environment becomes more complex, optical guided weapons will face increasingly complex photoelectric interference environment. This paper analyzes the photoelectric interference and interference mode faced by the optical detection system used in surface-to-air missiles, also gives anti-interference methods and simulation results, aiming at providing reference for anti-interference design of surface-to-air missiles. © 2024 SPIE. All rights reserved.

关键词： Surface to air missiles

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Tailoring conductive network Zn@NPC@MWCNTs nanocomposites derived from ZIF-8 as high-performance electromagnetic absorber for the whole X-Band

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Defence technology（防务技术） 2023年第5期23卷 189-200页

作者： Shi-bin Lu Ying Meng Hai-bo Wang Xian-wei Jiang Jin Yang Ning Wei Lin Jin Li-juan Wan Hao Tang Qian-qian Hou Anhui Province Key Laboratory of Simulation and Design for Electronic Information System Hefei Normal UniversityHefei230601PR China Universities Joint Key Laboratory of Photoelectric Detection Science and Technology in Anhui Province Hefei Normal UniversityHefei230601PR China

A porous 3D cross-linked conductive network pierced by multi-wall carbon nanotubes(MWCNTs) was successfully designed from zeolitic imidazolate framework-8(ZIF-8). Zn@NPC@MWCNTs composites were tailored by the facile regulating the mass ratios and thermal annealing treatment. Due to the combination of less eddy current loss and dielectric loss together with multiple reflection attenuation caused by a unique structure. With a 10 wt% filler loading, the Zn@NPC@MWCNTs composites carbonized at 800℃ show two high reflection loss(RL) values with different thicknesses. An RL value is-53.18 dB with 4.09 mm thickness in the C-Band(4-8 GHz), and a minimum RL can reach-74.83 d B(10.8 GHz)with a matching thickness of 2.749 mm. The effective absorption bandwidth is 4 GHz(from 8 to 12 GHz,RL ≤-10 d B), which just covers the full X-band. Low cost and easy preparation can also provide advantages to develop MOF-based materials as effective EMW absorbents.

关键词： ZIF-8 Electromagnetic wave absorption X-band C-Band

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Machine Learning Security Analysis Framework Based on Threat Matrix 8

Machine Learning Security Analysis Framework Based on Threat...

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8th International Conference on Data science in Cyberspace, DSC 2023

作者： Li, Hu Ma, Qiongmin Zhang, Ming Kuang, Xiaohui National Key Laboratory of Science and Technology on Information System Security Beijing China National Key Laboratory for Complex Systems Simulation Beijing China

ISBN: (纸本)9798350331035

Machine Learning and Artificial Intelligence technology accelerates technological progress and promotes social development, but also brings many security problems. Machine learning models may be affected, deceived, controlled or destroyed at different stages, e.g. training and inference, which may lead to serious consequences. In view of the main stages of the life cycle of machine learning, we summarizes the related attack and defense technologies based on threat matrix, makes a comprehensive and systematic analysis on the security issues of machine learning, and puts forward several security protection suggestions for intelligent information systems. © 2023 IEEE.

关键词： Artificial Intelligence Machine Learning Security Analysis Threat Matrix

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