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Quantitative assessment and visualization of flight risk induced by coupled multi-factor under icing conditions

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Chinese Journal of Aeronautics 2020年第8期33卷 2146-2161页

作者： Yang wei Haojun XU Yuan xue Xiaocong Duan School of Aeronautics Engineering Air Force Engineering UniversityXi'an 710038China

Aircraft icing has been proven to be one of the most serious threats to flight safety. During the analysis of flight risk under icing conditions, quantitative assessment and visualization of flight risk are quite essential as they provide safe manipulation strategies in intricate ***, they are rarely studied. Since the icing flight accidents are the result of the coupling of multiple unfavorable factors, in present study, we have proposed a method to quantitatively assess flight risk induced by multi-factor coupling under icing conditions by Monte-Carlo simulation and multivariate extreme value theory. The results demonstrate that the flight risk probability increases with the rise of unfavorable factors. Besides, a flight risk visualization method named flight safety window has been presented to build the flight risk distribution cloud maps in different complex conditions. The cloud maps show that the icing would give rise to atrophy of the safety scope, and the consequence would be even more severe when coupled with other more unfavorable factors. The proposed methods in this study would be useful in flight risk analysis under icing conditions and can enhance the pilot's situational awareness in selecting correct strategies within the safety zone to avoid unsafe manipulation.

关键词： Flight risk Icing Multivariate extreme value theory Quantitative assessment Visualization

Deep eutectic solvent-induced synthesis of Ni-Fe catalyst with excellent mass activity and stability for water oxidation

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Green Energy & Environment 2023年第3期8卷 852-863页

作者： Ruichang xue Mengwei Guo Zhuoming wei Qibo Zhang Key laboratory of Ionic liquids Metallurgy Faculty of Metallurgical and Energy EngineeringKunming University of Science and TechnologyKunming650093China State Key laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan Province Kunming650093China

Ni-Fe bimetallic electrodes are currently recognized as a kind of benchmark transition metal-based oxygen evolution reaction(OER)*** synthesis of Ni-Fe bimetallic electrode materials with excellent catalytic activity and satisfied stability by a simple and low-cost route is still a big ***,well-defined Ni-Fe nanoparticles in-situ developed on a planar Fe substrate(Ni-Fe NPs/Fe)is fabricated via a facile one-step galvanic replacement reaction(GRR)carried out in an Ethaline-based deep eutectic solvent(DES).The prepared Ni-Fe NPs/Fe exhibits outstanding OER performance,which needs an overpotential of only 319 mV to drive a current density of 10 mA cm^(-2),with a small Tafel slope of 41.2 mV dec^(-1) in 1.0 mol l^(-1) KOH,high mass activity(up to 319.78 A g^(-1) at an overpotential of 300 mV)and robust durability for 200 ***,the Ni-Fe bimetallic oxygen-evolution electrode obtained from the Ethaline-based DES is catalytically more active and durable than that of its counterpart derived from the 4.2 mol l^(-1) NaCl aqueous *** reason for this is mainly related to the different morphology and surface state of the Ni-Fe catalysts obtained from these different solvent environments,particularly for the differences in phy-chemical properties,active species formed and deposition kinetics,offered by the Ethaline-based DES.

关键词： Ni-Fe catalysts Galvanic replacement reaction Deep eutectic solvent Oxygen evolution reaction

Data fusing and joint training for learning with noisy labels

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Frontiers of Computer Science 2022年第6期16卷 63-70页

作者： Yi wei Mei xue Xin lIU Pengxiang XU College of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing211816China Beijing Seetatech Technology Co. LtdBeijing100029China

It is well known that deep learning depends on a large amount of clean *** of high annotation cost,various methods have been devoted to annotating the data ***,a larger number of the noisy labels are generated in the datasets,which is a challenging *** this paper,we propose a new method for selecting training data ***,our approach fits a mixture model to the per-sample loss of the raw label and the predicted label,and the mixture model is utilized to dynamically divide the training set into a correctly labeled set,a correctly predicted set,and a wrong ***,a network is trained with these sets in the supervised learning *** to the confirmation bias problem,we train the two networks alternately,and each network establishes the data division to teach the other *** optimizing network parameters,the labels of the samples fuse respectively by the probabilities from the mixture *** on CIFAR-10,CIFAR-100 and Clothing1M demonstrate that this method is the same or superior to the state-of-the-art methods.

关键词： deep learning noisy labels data fusing

Novel camera calibration method based on invariance of collinear points and pole-polar constraint

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Journal of Systems Engineering and Electronics 2023年第3期34卷 744-753页

作者： wei liang ZHANG Guiyang HUO Ju xue Muyao School of Electrical Engineering and Automation Harbin Institute of TechnologyHarbin 150001China School of Mechanical Engineering Changshu Institute of TechnologySuzhou 215500China Space Propulsion Technology Research Institute Shanghai Academy of Spaceflight TechnologyShanghai 201109China

To address the eccentric error of circular marks in camera calibration,a circle location method based on the invariance of collinear points and pole–polar constraint is proposed in this ***,the centers of the ellipses are extracted,and the real concentric circle center projection equation is established by exploiting the cross ratio invariance of the collinear ***,since the infinite lines passing through the centers of the marks are parallel,the other center projection coordinates are expressed as the solution problem of linear *** problem of projection deviation caused by using the center of the ellipse as the real circle center projection is addressed,and the results are utilized as the true image points to achieve the high precision camera *** demonstrated by the simulations and practical experiments,the proposed method performs a better location and calibration performance by achieving the actual center projection of circular *** relevant results confirm the precision and robustness of the proposed approach.

关键词： camera calibration cross ratio invariance infinite lines eccentricity error compensate

Diffusion coefficient of Ti^4+ in calcium ferrite/calcium titanate diffusion couple

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International Journal of Minerals,Metallurgy and Materials 2020年第9期27卷 1216-1225页

作者： Wang wei Hong-rui Yue Xiang-xin xue School of Metallurgy Northeastern UniversityShenyang 110819China

This study investigated the interdiffusion of calcium ferrite/calcium titanate system in the time range of 0-120 min by the diffusion couple method in a CO/N2 reducing atmosphere at 700℃.The results show that after the diffusion reaction occurred,no longitudinal agglomerations were present on the substrate surface on the calcium titanate *** the diffusion time was increased to 105 min,a net vacancy flow from calcium titanate to calcium ferrite might have occurred,causing the surface of the calcium ferrite substrate to *** thickness of the diffusion layer of the calcium ferrite/calcium titanate system was about 17-48μm,which conforms to the parabolic law of *** diffusion coefficient and the Ti^4+concentration in the calcium ferrite/calcium titanate system are *** shows an increase in the diffusion coefficient with the increase of Ti^4+concentration,and the diffusion coefficient value was in the range of 10^−12-10^−11 cm^2·s^−1.

关键词： vanadium-titanium sinter diffusion couple calcium ferrite calcium titanate diffusion coefficient

Crowd Density Field Estimation Based on Crowd Dynamics Theory and Social Force Model

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Chinese Journal of Electronics 2019年第3期28卷 521-528页

作者： wei Xinlei DU Junping lIANG Meiyu xue Zhe Beijing Key lab of Intelligent Telecommunication Software and Multimedia School of Computer ScienceBeijing University of Posts and Telecommunications

The local crowd density and the crowd distribution estimation tasks are useful but *** are two main problems which limit the performance of existing algorithms. The first one is that there are not enough labeled training samples to build the highperformance estimation model. Another one is that existing methods lack the supports of physical theories of the crowd. To remedy them, a novel crowd density field model is proposed, which is deduced by jointing crowd dynamics theory and social force model. A crowd counting method based on the proposed crowd density field model is introduced to measure the proposed crowd density field model. Extensive experiments confirm the effectiveness of the proposed plan.

关键词： Social force model Crowd dynamics Crowd density field Computer vision

Joint Sample Position Based Noise Filtering and Mean Shift Clustering for Imbalanced Classification learning

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Tsinghua Science and Technology 2024年第1期29卷 216-231页

作者： lilong Duan wei xue Jun Huang Xiao Zheng School of Computer Science and Technology Anhui University of TechnologyMaanshan 243032China Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefei 230088China

The problem of imbalanced data classification learning has received much *** classification algorithms are susceptible to data skew to favor majority samples and ignore minority *** weighted minority oversampling technique(MWMOTE)is an effective approach to solve this problem,however,it may suffer from the shortcomings of inadequate noise filtering and synthesizing the same samples as the original minority *** this end,we propose an improved MWMOTE method named joint sample position based noise filtering and mean shift clustering(SPMSC)to solve these ***,in order to effectively eliminate the effect of noisy samples,SPMsC uses a new noise filtering mechanism to determine whether a minority sample is noisy or not based on its position and distribution relative to the majority *** that MWMOTE may generate duplicate samples,we then employ the mean shift algorithm to cluster minority samples to reduce synthetic replicate ***,data cleaning is performed on the processed data to further eliminate class *** on extensive benchmark datasets demonstrate the effectiveness of SPMsC compared with other sampling methods.

关键词： imbalanced data classification oversampling noise filtering clustering

Analysis of blockchain protocol against static adversarial miners corrupted by long delay attackers

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Science China(Information Sciences) 2020年第3期63卷 49-63页

作者： Quan YUAN Puwen wei Keting JIA Haiyang xue Key laboratory of Cryptologic Technology and Information Security Ministry of EducationShandong University Department of Computer Science and Technology Tsinghua University State Key laboratory of Information Security Institute of Information EngineeringChinese Academy of Sciences Data Assurance and Communication Security Research Center Chinese Academy of Sciences

Bitcoin, which was initially introduced by Nakamoto, is the most disruptive and impactive cryptocurrency. The core Bitcoin technology is the so-called blockchain protocol. In recent years, several studies have focused on rigorous analyses of the security of Nakamoto’s blockchain protocol in an asynchronous network where network delay must be considered. wei, Yuan, and Zheng investigated the effect of a long delay attack against Nakamoto’s blockchain protocol. However, their proof only holds in the honest miner setting. In this study, we improve wei, Yuan and Zheng’s result using a stronger model where the adversary can perform long delay attacks and corrupt a certain fraction of the miners. We propose a method to analyze the converge event and demonstrate that the properties of chain growth, common prefix, and chain quality still hold with reasonable parameters in our stronger model.

关键词： blockchain bitcoin random oracle delay consensus protocol

A Fusion Kalman Filter and UFIR Estimator Using the Influence Function Method

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IEEE/CAA Journal of Automatica Sinica 2022年第4期9卷 709-718页

作者： wei xue Xiaoli luan Shunyi Zhao Fei liu IEEE the Key laboratory of Advanced Process Control for light Industry(Ministry of Education) Institute of AutomationJiangnan University

In this paper,the Kalman filter(KF)and the unbiased finite impulse response(UFIR)filter are fused in the discrete-time state-space to improve robustness against *** avoid the problem where fusion filters may give up some advantages of UFIR filters by fusing based on noise statistics,we attempt to find a way to fuse without using noise *** fusion filtering algorithm is derived using the influence function that provides a quantified measure for disturbances on the resulting filtering outputs and is termed as an influence finite impulse response(IFIR)*** main advantage of the proposed method is that the noise statistics of process noise and measurement noise are no longer required in the fusion process,showing that a critical feature of the UFIR filter is *** numerical example and a practice-oriented case are given to illustrate the effectiveness of the proposed *** is shown that the IFIR filter has adaptive performance and can automatically switch from the Kalman estimate to the UFIR estimates according to operating ***,the proposed method can reduce the effects of optimal horizon length on the UFIR estimate and can give the state estimates of best accuracy among all the compared methods.

关键词： Fusion filter influence function Kalman filter(KF) robustness unbiased finite impulse response(FIR)