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Construction mechanism of whitenization weight function and its application in grey clustering evaluation

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Journal of Systems Engineering and Electronics 2019年第1期30卷 121-131页

作者： XIE Naiming SU Bentao CHEN Nanlei college of Economics and Management Nanjing University of Aeronautics and Astronautics

The clustering evaluation can be used to scientifically classify the objects to be evaluated according to the information aggregation of various evaluation rules. In grey weighted clustering evaluation, the index clustering rule relies on the construction of the whitenization weight function, while the existing construction method of the linear function lacks the construction mechanism analysis and validity explanation. A normative construction principle is put forward by analyzing the construction mechanism of the function. Through proving the normative principle of the function,the basic modal function(BMF) is proposed and characterized by different function forms. Then, a new type of the whitenization weight function and its grey clustering evaluation model algorithm are given by studying the mechanism and nature of the construction of different forms of the function. Finally, the comparative study for self-innovation capability of defense science and technology industry(DSTI) is taken as an example. The results show that the different construction ways of the function have an effect on the clustering result. The proposed construction mechanism can better explain the index clustering rules and evaluation effectiveness,which will perfect the theoretical system of grey clustering evaluation and be applied to practice effectively.

关键词： whitenization weight function grey system theory grey clustering evaluation.

Noncertainty-equivalent observer-based noncooperative target tracking control for unmanned aerial vehicles

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Science China(Information sciences) 2022年第5期65卷 142-156页

作者： Kenan YONG Mou CHEN Qingxian WU college of Automation Engineering Nanjing University of Aeronautics and Astronautics

Target tracking is a typical and challenging scenario that is required to be executed by unmanned aerial vehicles(UAVs) in operational environments. This work investigates the noncooperative target tracking control problem for UAVs. An integrated model is constructed by combining the dynamics of both the line-of-sight variables and the acceleration components. Particularly, the dynamics of the acceleration components, that contain unmeasurable states, characterize the relative motion between the noncooperative target and the UAV. To estimate these states, a globally convergent observer is developed by utilizing the noncertainty-equivalent(NCE) structure. With the integrated model and the NCE observer, an output-feedback target tracking control scheme is proposed using the dynamic surface control technique and the prescribed performance control method. Based on the Lyapunov approach, the relative spatial positions of the target and the UAV are proved to always stay within a specified operation region and ultimately converge to a small terminal region. Finally, simulation results are presented to illustrate the effectiveness of the proposed target tracking control scheme.

关键词： noncooperative target tracking unmanned aerial vehicles noncertainty-equivalent observer prescribed performance control

Response surface methodology-based hybrid robust design optimization for complex product under mixed uncertainties

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Journal of Systems Engineering and Electronics 2019年第2期30卷 308-318页

作者： WAN Liangqi CHEN Hongzhuan OUYANG Linhan college of Economics and Management Nanjing University of Aeronautics and Astronautics

Minimizing the impact of the mixed uncertainties(i.e.,the aleatory uncertainty and the epistemic uncertainty) for a complex product of compliant mechanism(CPCM) quality improvement signifies a fascinating research topic to enhance the ***, most of the existing works in the CPCM robust design optimization neglect the mixed uncertainties, which might result in an unstable design or even an infeasible design. To solve this issue, a response surface methodology-based hybrid robust design optimization(RSM-based HRDO) approach is proposed to improve the robustness of the quality characteristic for the CPCM via considering the mixed uncertainties in the robust design optimization. A bridge-type amplification mechanism is used to manifest the effectiveness of the proposed approach. The comparison results prove that the proposed approach can not only keep its superiority in the robustness, but also provide a robust scheme for optimizing the design parameters.

关键词： response surface methodology (RSM) hybrid robust design optimization (HRDO) uncertainty complex product of compliant mechanism (CPCM)

Study on segmented distribution for reliability evaluation

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Chinese Journal of aeronautics 2017年第1期30卷 310-329页

作者： Li Huaiyuan Zuo Hongfu Su Yan Xu Juan Yin Yibing School of Software Engineering Jinling Institute of Technology college of Civil Aviation Nanjing University of Aeronautics and Astronautics

In practice, the failure rate of most equipment exhibits different tendencies at different stages and even its failure rate curve behaves a multimodal trace during its life cycle. As a result,traditionally evaluating the reliability of equipment with a single model may lead to severer ***, if lifetime is divided into several different intervals according to the characteristics of its failure rate, piecewise fitting can more accurately approximate the failure rate of equipment. Therefore, in this paper, failure rate is regarded as a piecewise function, and two kinds of segmented distribution are put forward to evaluate reliability. In order to estimate parameters in the segmented reliability function, Bayesian estimation and maximum likelihood estimation（MLE） of the segmented distribution are discussed in this paper. Since traditional information criterion is not suitable for the segmented distribution, an improved information criterion is proposed to test and evaluate the segmented reliability model in this paper. After a great deal of testing and verification,the segmented reliability model and its estimation methods presented in this paper are proven more efficient and accurate than the traditional non-segmented single model, especially when the change of the failure rate is time-phased or multimodal. The significant performance of the segmented reliability model in evaluating reliability of proximity sensors of leading-edge flap in civil aircraft indicates that the segmented distribution and its estimation method in this paper could be useful and accurate.

关键词： Bayesian estimates Gibbs sampling method Maximum likelihood estima-tion Proximity sensors in leadingedge flap in aircraft Reliability Segmented distribution Weibull distribution

Thermodynamics of Molten Pool Predicted by Computational Fluid Dynamics in Selective Laser Melting of Ti6Al4V:Surface Morphology Evolution and Densification Behavior

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Computer Modeling in Engineering & sciences 2020年第9期124卷 1085-1098页

作者： Donghua Dai Dongdong Gu Qing Ge Chenglong Ma Xinyu Shi Han Zhang college of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing210016China Jiangsu Provincial Engineering Laboratory for Laser Additive Manufacturing of High-Performance Metallic Components Nanjing University of Aeronautics and AstronauticsNanjing210016China

The three-dimensional physical model of the randomly packed powder material irradiated by the laser beam was established,taking into account the transformation of the material phase,the melt spreading and the interaction of the free surface of the molten pool and the recoiling pressure caused by the material evaporation during the selective laser *** of the processing parameters on the thermal behavior,the material evaporation,the surface morphology and the densification behavior in the connection region of the molten pool and the substrate was *** was shown that the powder material underwent the transformation from the partial melting state to the complete melting state and finally to the overheating state with the applied laser energy density increasing from 167 J/mm^(3) to 417 J/mm^(3).Therefore,the solidified track ranged from the discontinuous tracks with the rough surface to the continuous tracks with residual porosities,then to the continuous and dense tracks and terminally to the fluctuated tracks with the increase in the laser energy ***,the laser energy effect depth was maintained the positive relationship with the laser energy *** vortex velocity obtained in the free surface of the molten pool towards to the rear region in the opposite laser scan direction promoted the melt convection to the edge region of the molten pool as the laser energy density was higher than 277 J/mm^(3),demonstrating the efficient energy dissipation from the center of the irradiation region to the whole part of the molten pool and the attendant production of the sufficient melt ***,the efficient spreading of the molten pool and the metallurgical bonding ability of the melt with the substrate was obtained at the optimized laser energy density of 277 J/mm^(3).However,the severe material evaporation would take place as the melt was overheated,resulting in the formation of the residual pores and poor surface quality.

关键词： Additive manufacturing melt convection surface morphology densification behavior numerical simulation

A self-adaptive grey forecasting model and its application

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Journal of Systems Engineering and Electronics 2022年第3期33卷 665-673页

作者： TANG Xiaozhong XIE Naiming college of Economics and Management Nanjing University of Aeronautics and AstronauticsNanjing 211106China Department of Industry and Finance Huangshan Vocational and Technical CollegeHuangshan 245000China

GM(1,1)models have been widely used in various fields due to their high performance in time series ***,some hypotheses of the existing GM(1,1)model family may reduce their prediction performance in some *** solve this problem,this paper proposes a self-adaptive GM(1,1)model,termed as SAGM(1,1)model,which aims to solve the defects of the existing GM(1,1)model family by deleting their modeling ***,a novel multi-parameter simultaneous optimization scheme based on firefly algorithm is proposed,the proposed multi-parameter optimization scheme adopts machine learning ideas,takes all adjustable parameters of SAGM(1,1)model as input variables,and trains it with firefly *** Sobol’sensitivity indices are applied to study global sensitivity of SAGM(1,1)model parameters,which provides an important reference for model parameter ***,forecasting capability of SAGM(1,1)model is illustrated by Anhui electricity consumption *** show that prediction accuracy of SAGM(1,1)model is significantly better than other models,and it is shown that the proposed approach enhances the prediction performance of GM(1,1)model significantly.

关键词： grey forecasting model GM(1,1)model firefly algo-rithm Sobol’sensitivity indices electricity consumption prediction

Ranking grey numbers based on dominance grey degrees

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Journal of Systems Engineering and Electronics 2014年第4期25卷 618-626页

作者： Yong Liu Jeffrey Forrest Naiming Xie college of Economics and Management Nanjing University of Aeronautics and Astronautics School of Business Jiangnan University Mathematics Department Slippery Rock University of USA

With respect to the decision making problems where a lot of fuzzy and grey information always exists in the real-life decision making information system methods as fuzzy mathematics, it is difficult for such uncertainty probability, and interval numbers to deal with. To this end, based on the thought and method of grey numbers, grey degrees and interval numbers, the concept of dominance grey degree is defined. And then a method of ranking interval grey numbers based on the dominance grey degree is proposed. After discussing the relevant properties, the paper finally uses an example to demonstrate the effectiveness and applicability of the model. The result shows that the proposed model can more accurately describe uncertainty decision making problems, and realize the total ordering process for multiple-attribute decision-making problems.

关键词： grey information dominance grey degree intervalgrey number total ordering.

The Online Political Participation and the Role of Chinese Government

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The Online Political Participation and the Role of Chinese G...

Effects of stimulating frequency of NIR LEDs light irradiation on forehead as quantified by EEG measurements

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作者： HUANG Xiao-ru MA Jie college of humanities and social sciences Nanjing University of Aeronautics and Astronautics

The Internet offers a new opportunity for political participation and civic engagement. The thesis tries to discuss the role of the government based on the analysis of the forms of online political participation in China. As a new political phenomenon, there are various forms of online political participation such as offering suggestions online, anticorruption online, online mass incidents and political apathy. But the side effects of online political participation, including the ambiguity of the participants, the difficulty of information screening, the power asymmetry and the tragedy of the commons, may bring about new challenges to the government. Therefore, the government should try its best to be a listener of the online public opinion, a participant of network politics and a guide of cyber democracy.

关键词： Internet Online political participation Challenges Government role

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Journal of Innovative Optical Health sciences 2021年第2期4卷 19-30页

作者： Liuye Yao Zhiyu Qian Yangyang Liu Zhou Fang Weitao Li Lidong Xing college of Automation Nanjing University of Aeronautics and AstronauticsNanjingJiangsu 210016P.R.China college of Information and Communication Engineering Nanjing Institute of TechnologyNanjing Jiangsu 211167P.R.China

Near-infrared(NIR)light has been shown to produce a range of physiological effects in hunans,however,there is still no agreement on whether and how a single parameter,like the flicker frequency of NIR light,affects the *** 810 nm NIR LED was used as the *** subjects participated in this *** subjects were randomly divided into four *** group underwent a 30-minute NIR LED radiation with four different frequencies(i.e.,0 Hz,5 Hz,10 Hz and 20 Hz,respectively)on the *** remaining 10 subjects formed the control group,in which they underwent a 30-minute rest period without light *** signals of all subjects during each test were *** frequency(GF),relative energy change,and sample entropy were *** experimental groups had larger GF values compared to the control *** stimulation frequency would cause larger growth of GF(F=14.75,P<0.001).The amplitude of alpha waves relative energy increased,while theta waves decreased remarkably in the experimental groups(p<0.02),and the extent of increase/decrease was larger at higher stimulation frequency,compared to that of the *** entropy of electrodes in the frontal areas were much larger than those in other brain areas in the experimental groups(p<0.001).Larger frequency of the NIR LED light would cause more distinct brain activities in the stimulated *** indicates that NIR LED light may have a positive effect on modulating brain *** results may help improve the design of photobiomodulation treatments in the future.

关键词： Photobiomodulation LED light therapy near-infrared light gravity frequency relative energy