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Lower bound for transient growth of inclined buoyancy layer

Applied Mathematics and Mechanics(English Edition) 2017年第6期38卷 779-796页

作者： Xiangming XIONG Jianjun TAO 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 ofEngineeringPeking University

The relationship between stabilities of the buoyancy boundary layers along an inclined plate and a vertical plate immersed in a stratified medium is studied theoretically and numerically. The eigenvalue problem of energy stability is solved with the method of descending exponentials. The disturbance energy is found to be able to grow to 11.62 times as large as the initial disturbance energy for Pr = 0.72 when the Grashof number is between the critical Grashof numbers of the energy stability and the linear stability. We prove that, with a weighted energy method, the basic flow of the vertical buoyancy boundary layer is stable to finite-amplitude streamwise-independent disturbances.

关键词： natural convection boundary layer energy method transient growth

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Architecture analysis for avionics prognostics and health management system

Architecture analysis for avionics prognostics and health ma...

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2021 CAA Symposium on Fault Detection, Supervision, and Safety for Technical Processes, SAFEPROCESS 2021

作者： Chen, Runfeng Hu, Yang Hou, Yanze Beijing China Science and Technology on Complex Aviation System Simulation Laboratory 9236 Beijing China

ISBN: (纸本)9781665401159

Prognostics and Health Management (PHM) has been researched on for recent years, and extensive studies have been done on hot topics into this field, such as diagnostics, prognostics, and decision making. However, how to evaluate PHM system architecture is still lacking. This is particularly important when designing avionics system equipped with PHM functions. We propose a general, time-variant architecture model that can simulate PHM system. Performance metrics are calculated to quantitatively evaluate the system architecture. This is useful to find differences of architectures in the earlier design stage in engineering. A case study is presented of the use of architecture modelling to show the effectiveness. And future works are discussed. © 2021 IEEE.

关键词： Decision making

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MilChat: A Large Language Model and Application for Military Equipment 7

MilChat: A Large Language Model and Application for Military...

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7th International Conference on Machine Learning and Natural Language Processing, MLNLP 2024

作者： Xue, Liu Jie, Liu Peipei, Zhu Tao, Xiang Southwest China Institute of Electronic Technology National Key Laboratory of Complex Aviation System Simulation Chengdu China

ISBN: (纸本)9798350354973

To offer the military personnel a good service of assisting them to get information about enemy's equipment outside Internet, we build a system named MilChat which includes a large language model that has the ability to generate texts and an application which is easy to use. The model of MilChat is fine-tuned by the method of LoRA with military datasets from the basic model, Qwen-7B-Chat which is opensource and has good performance. After fine-tuning, the new model has higher scores than the basic one. Besides, we use the method of Prompt Learning to limit the answers into a standard format. Therefore, it is more accurate and professional than the basic model. This study has also a value of industrial application. © 2024 IEEE.

关键词： Military equipment

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Architecture transformation research on joint border defense systems-of-systems 2021

Architecture transformation research on joint border defense...

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2021 5th International Conference on Management Engineering, Software Engineering and Service sciences, ICMSS 2021

作者： Zhang, Mengmeng Yi, Shuanghui Lin, Menglong Chen, Honghui Science and Technology on Information Systems Engineering Laboratory China National Key Laboratory for Complex System Simulation China

ISBN: (纸本)9781450389709

Currently, with the deepening of development and open of China's border, issues of border joint defense become increasingly arduous. Traditional means of cooperation and coordination are far from being able to align requirements;information systems of different joint defense units are difficult to interconnect and interoperate;the previous results of joint defense informatization are difficult to inherit. The main reason is the lack of border joint defense information construction with a top-level design approach. Via the lens of top-level design, this paper establishes a multi-viewpoint architecture framework and transformation process, develops the as-is and to-be joint defense architecture, and finally analyzes transformation principles from the as-is architecture to to-be architecture. This paper mainly explores the architecture transformation mechanisms under the border joint defense scenario. © 2021 ACM.

关键词： Architecture

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MTL-JER: Meta-Transfer Learning for Low-Resource Joint Entity and Relation Extraction 3

MTL-JER: Meta-Transfer Learning for Low-Resource Joint Entit...

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3rd International Conference on Neural Networks, Information and Communication Engineering, NNICE 2023

作者： Peng, Da Pei, Zhongmin Mo, Delin Space Engineering University Science and Technology on Complex Electronic System Simulation Laboratory Beijing China Institute of War Studies Academy of Military Sciences

ISBN: (纸本)9798350335972

Joint entity and relation extraction has achieved impressive advances in NLP, such as document understanding and knowledge graph construction. The typical methods for entity and relation extraction typically break down the joint task into several smaller components or stages for ease of implementation, but this leads to a loss of the interconnected knowledge in the triple. Hence, we propose to model the triple in one module jointly. Furthermore, the labeling of a joint entity and relation extraction tasks is costly and domain-specific;therefore, it is important to improve its performance on low-resource data and domain adaption. To address this issue, we suggest using two sources that are rich in information, namely pre-trained models on large data and multi-domain text corpora. Pretraining allows us to provide the model with the fundamental ability to perform joint entity and relationship extraction. Second, through meta-learning on multi-domain text, we can improve the model's generalization capabilities, enabling it to perform well even with limited data. We present MTL-JER, a Meta-Transfer Learning method for Joint Entity and Relation Extraction in low-resource settings in this paper. Using exhaustive experiments on five datasets, we prove that our model obtains optimal results. © 2023 IEEE.

关键词： Extraction

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LEO Satellite Network Traffic Forecasting based on ARIMA-BPNN Model 3

LEO Satellite Network Traffic Forecasting based on ARIMA-BPN...

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3rd International Conference on electronic Information Engineering and Computer Communication, EIECC 2023

作者： Han, Chi Xiong, Wei Yu, Ronghuan Fu, Jingyu Space Engineering University Science and Technology on Complex Electronic System Simulation Laboratory Beijing China Jiuquan Satellite Launch Center Jiuquan China

ISBN: (纸本)9798350359961

Satellite network traffic forecasting provides key information for routing and resource allocation, which is important for the efficient operation of satellite network. However, due to the self-similarity and long-range dependence (LRD) of satellite network traffic, traditional linear or non-linear network traffic forecasting models cannot achieve sufficient forecasting accuracy. A combined model of satellite network traffic forecasting based on BPNN and ARIMA is proposed. BPNN is adopted to forecast the residuals. EMD-ARIMA and BPNN forecasting results are combined to achieve satellite network traffic forecasting. Experimental results on the satellite network traffic data generated by the ON/OFF model show that forecast accuracy of the proposed method is better than traditional model, which verifies the effectiveness of the proposed satellite network traffic forecast model. © 2023 IEEE.

关键词： BP neural network empirical mode decomposition intrinsic mode function long-range dependence satellite network

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Optimization of GM (1,1) model based on bilevel programming

Optimization of GM (1,1) model based on bilevel programming

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2013 5th International Conference on Intelligent Human-Machine systems and Cybernetics, IHMSC 2013

作者： Chen, Bolin Ke, Hongfa School of Optoelectronic Engineering Changchun University of Science and Technology Changchun China Laboratory of Complex Electronic System Simulation Academy of Equipment Beijing China

ISBN: (纸本)9780769550114

GM (1, 1) is a biased grey exponential model, whose accuracy depends on the structure of background values and the selection of original conditions. Current literatures optimized GM (1, 1) models just by optimizing background values or original conditions separately, or by combining them jointly. However, these methods all ignored the accumulative errors between the optimization of background value and the optimization of original condition. Besides, they can not reflect the dynamic characteristics of the data sequence. Considering the accumulation and spread of the error between the optimization of background value and that of original condition, a new optimized model of GM (1, 1) Based on bilevel programming is put forward. The bilevel programming model is set up on the basis of two objective functions which minimize the square sum of relative errors. Various weights are optimized for individual data sequence. Furthermore, a validity analysis method Based on the grey relational degree between simulation data sequence and the original one is introduced. The simulation results show that the proposed model has extremely high fitting accuracy regardless of the scale of development coefficient. Both of approachability and similarity of the simulation data sequence to the original one reach the best. © 2013 IEEE.

关键词： Errors

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Fast measurement and prediction method for electromagnetic susceptibility of receiver

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Journal of systems Engineering and electronics 2024年第2期35卷 275-285页

作者： CHEN Yan LU Zhonghao LIU Yunxia State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and TechnologyNational University of Defense TechnologyChangsha 410073China State Key Laboratory of Astronautic Dynamics Xi’an 710043China

Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequency is proposed to improve the traditional two-tone ***,two signal generators are used to generate signals at the radio frequency(RF)by frequency scanning,and then a rapid measurement at the intermediate frequency(IF)output port is carried out to obtain a huge amount of sample data for the subsequent ***,the IF output response data are modeled and analyzed to construct the linear and nonlinear response constraint equations in the frequency domain and prediction models in the power domain,which provide the theoretical criteria for interpreting and predicting electromagnetic susceptibility(EMS)of the *** experiment performed on a radar receiver confirms the reliability of the method proposed in this *** shows that the interference of each harmonic frequency and each order to the receiver can be identified and predicted with the sensitivity *** on this,fast and comprehensive evaluation and prediction of the receiver’s EMS in complex environment can be efficiently realized.

关键词： electromagnetic susceptibility(EMS) receiver dualchannel multi-frequency nonlinear response frequency domain power domain

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Research on modeling and simulation of complex adaptive systems based on multi-agent

Research on modeling and simulation of complex adaptive syst...

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

作者： Liao, Shan Liang Lai, Jia Zhe Company of Postgraduate Management The Academy of Equipment Beijing China Science and Technology on Complex Electronic System Simulation Laboratory The Academy of Equipment Beijing China

ISBN: (纸本)9783037857700

With the rapid development of complex adaptive systems, traditional modeling and simulation methods have been unable to meet the need of accurate modeling of complex adaptive systems. Therefore, we need a way to accurately describe the characteristics of complex adaptive systems modeling and simulation. Multi-Agent modeling and simulation methods focus on the study of the interaction between multiple subjects. It is an effective way to study complex adaptive system. This paper analyzes the multi-agent modeling process, sets up a rumor spreading model of a small social network through multi-agent modeling and simulation methods,. The simulation results verify the correctness and accuracy of the model. © (2013) Trans Tech Publications, Switzerland.

关键词： Adaptive systems

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A matching algorithm based on global viewpoint difference rectification for framework imagery

A matching algorithm based on global viewpoint difference re...

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IEEE International Conference on Communication Problem-Solving, ICCP 2015

作者： Shibing, Zhu Changqing, Li Sheng, Yang Chi, Zhou Department of Information Equipment Academy of Equipment Beijing101416 China Science and Technology on Complex Electronic System Simulation Laboratory Beijing101416 China

ISBN: (纸本)9781467365437

Matching precision is very important and difficult in accurate photography, remote sensing and 3D reconstruction. After analyzing the advantages and shortcomings of current matching algorithms and the epipolar geometry, a new matching algorithm based on global viewpoint difference rectification for framework imagery is devised. Without the aid of orientation parameters, this algorithm contains three parts, the scale rectification for an overall comfortable of the image, the viewport rectification for compensating the bias between the vertical plane of the primary optical axis and the main plane of the scene, and the consistent transformation of two images with different viewports. Following, the details of the implementation of our methods are also given. The validation experiments of the matching precision show that, the new algorithm can improve the precision dramatically, which is better than many other good matching algorithms. © 2015 IEEE.

关键词： Computer vision

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