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Chinese Journal of Aeronautics 2007年第6期20卷 511-517页

作者： Wang Xinjun Feng zhenzhou Wang Fusheng Yue Zhufeng Department of Engineering Mechanics Northwestern Polytechnical University Xi ＇an 710072 China

Damage-modified nonlinear viscoelastic constitutive equation and failure criterion are introduced and the three-dimensional incremental forms are deduced based on the updated Lagrangian approach. A simple tensile test model and a split Hopkinson pressure bar model are built to verify the accuracy of the subroutine implemented within the non-linear finite element program LS-DYNA. A numerical model of bird strike on windshield is established to study the responses of windshield under three different bird velocities at three sites. The bird is represented by a cylinder with a hemisphere at each end and the contact-impact coupling algorithm is used in this study. It is found that the implemented subroutine can properly describe the mechanical behavior of polymethyl methaerylate under low and high strain rates and large deformation, and can be used validly.

关键词： bird strike damage-modified non-linear viscoelastic constitutive relation material subroutine windshield strain rate

An efficient algorithm for calculating Profust failure probability

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Chinese Journal of Aeronautics 2019年第7期32卷 1657-1666页

作者： Xiaobo ZHANG zhenzhou LYU Kaixuan FENG Chunyan LING School of Aeronautics Northwestern Polytechnical University

For efficiently estimating the Profust failure probability based on probability input variables and fuzzy-state assumption, a General Performance Function(GPF) expression is established under the strict mathematical derivation for the Profust reliability model. By constructing the GPF,the calculation of the Profust failure probability can be transformed into the calculation of the traditional failure probability. Then various existing methods for the traditional failure probability can be used to estimate the Profust failure probability. Due to the high efficiency of the Adaptive Kriging(AK) model and the universality of the Monte Carlo Simulation(MCS), AK inserted MCS(abbreviated as AK-MCS) has been proven to be an efficient method for estimating the failure probability. Therefore, the AK-MCS combined with the GPF(abbreviated as AK-MCS + GPF)is proposed for estimating Profust failure probability. The proposed method greatly reduces the computational cost while ensuring the accuracy. Finally, four examples are given to validate the proposed AK-MCS + GPF. The results of the examples show the rationality and the efficiency of the proposed AK-MCS + GPF.

关键词： Failure probability Fuzzy-state assumption General performance function Kriging model Profust reliability Reliability

Safety lifetime analysis method for multi-mode time-dependent structural system

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Chinese Journal of Aeronautics 2022年第11期35卷 294-308页

作者： Yingshi HU zhenzhou LU Ning WEI Xia JIANG Changcong ZHOU School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

It is important to determine the safety lifetime of Multi-mode Time-Dependent Structural System(MTDSS). However, there is still a lack of corresponding analysis ***, this paper establishes MTDSS safety lifetime model firstly, and then proposes a Kriging surrogate model based method to estimate safety lifetime. The first step of proposed method is to construct the Kriging model of MTDSS performance function by using extremum learning function. By identifying possible extremum mode of MTDSS, the performance function of MTDSS can be equivalently transformed into the one of Single-mode Time-Dependent Structure(STDS).The second step is to use the Advanced First Failure Instant Learning Function(AFFILF) to train the Kriging model constructed in the first step, so that the convergent Kriging model can identify the possible First Failure Instant(FFI) of STDS. Then safety lifetime can be searched quickly by dichotomy search. By using AFFILF, the minimum instant that the state is not accurately identified by the current Kriging model is selected as the training point, which avoids the unnecessary calculation which may be introduced into the existing First Failure Instant Learning Function(FFILF).In addition, the Candidate Sample Pool(CSP) reduction strategy is also adopted. By adaptively deleting the random candidate sample points whose FFI have been accurately identified by the current Kriging model, the training efficiency is further improved. Three cases show that the proposed method is accurate and efficient.

关键词： Kriging Learning function Lifetime System reliability Time-dependent reliability analysis

The Shaping of Citizenship Education in a Chinese Context

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Frontiers of Education in China 2013年第1期8卷 105-122页

作者： zhenzhou ZHAO Department of Social Sciences The Hong Kong Institute of EducationHong KongChina

The global flow of citizenship education in China has spurred much discussion in Chinese academic *** study explores the interaction between citizenship education and China’s the existing political-ideological education and moral education as a space is negotiated a space in the current“ideoscape.”A qualitative approach is adopted to synthesize the literature coming from China on citizenship education from an interpretive and critical *** research findings suggest:(a)The territory of orthodox political-ideological education is being narrowed down as its relationship with citizenship education is configured;(b)citizenship education and moral education are represented using different images to delineate their distinctions;and(c)the introduction of“global citizenship education”includes many new topics and competencies that expands the current *** study argues that the ongoing debates on citizenship education are deeply rooted in China’s structural transformation,in which society tends to be separated from *** negotiating its own territory,citizenship education reshapes China’s ideoscape in the education *** paper concludes by suggesting that citizenship education should make a unique contribution to facilitating young citizens in a reexamination of the values imbedded in political-ideological education and moral education with a new social consensus being reached through the communication of ideas.

关键词： citizenship global citizens ideoscape moral education political education ideology

Application of RS Codes in Decoding QR Code

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High Technology Letters 2003年第4期9卷 67-69页

作者：朱素霞 Ji zhenzhou Cao Zhiyan Computer Science Academy Harbin Institute of Technology Harbin 150001 P.R.China

The QR Code is a 2 dimensional matrix code with high error correction capability. It employs RS codes to generate error correction codewords in encoding and recover errors and damages in decoding. This paper presents several QR Code’s virtues, analyzes RS decoding algorithm and gives a software flow chart of decoding the QR Code with RS decoding algorithm.

关键词： QR Code RS codes decoding flow chart

NUMERICAL SIMULATION ALGORITHM FOR RELIABILITY ANALYSIS OF COMPLEX STRUCTURAL SYSTEM BASED ON INTELLIGENT OPTIMIZATION

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Chinese Journal of Mechanical Engineering 2006年第1期19卷 67-71页

作者： LUE zhenzhou LIU Chengli FU Lin School of Aeronautics Northwestern Polytechnical University Xi＇ an 710072 China

An efficient importance sampling algorithm is presented to analyze reliability of complex structural system with multiple failure modes and fuzzy-random uncertainties in basic variables and failure modes. In order to improve the sampling efficiency, the simulated annealing algorithm is adopted to optimize the density center of the importance sampling for each failure mode, and results that the more significant contribution the points make to fuzzy failure probability, the higher occurrence possibility the points are sampled. For the system with multiple fuzzy failure modes, a weighted and mixed importance sampling function is constructed. The contribution of each fuzzy failure mode to the system failure probability is represented by the appropriate factors, and the efficiency of sampling is improved furthermore. The variances and the coefficients of variation are derived for the failure probability estimations. Two examples are introduced to illustrate the rationality of the present method. Comparing with the direct Monte-Carlo method, the improved efficiency and the precision of the method are verified by the examples.

关键词： Importance sampling Simulated annealing algorithm Randomness Fuzziness

Churning loss characteristics of a wet three-phase high-speed reluctance motor

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第3期25卷 251-267页

作者： zhenzhou ZHANG Mingzhu DAI Chenchen ZHANG Yi CHEN Bin MENG College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China

With the increasing requirements of electro-hydrostatic actuators(EHAs)for power,volume,and pressure,there is a growing tendency in the industry to combine the motor and pump to form a so-called'motor pump'to improve the *** this paper,a novel structure for a wet three-phase high-speed reluctance motor pump is proposed,which can further improve integration by removing the dynamic seal on the pump shaft,thereby avoiding the problems of dynamic seal wear and oil leakage and improving heat dissipation under high-speed working ***,after the motor is wetted,the churning loss caused by immersion of the rotor in the oil causes additional fluid resistance *** on fundamental fluid mechanics,an analytical model of the churning torque of a wet motor was *** verify the accuracy of the analytical model,a simulation model of churning loss was established based on computational fluid dynamics(CFD),and the churning torque and flow field state were ***,an experimental prototype was designed and manufactured,and a test bench for churning loss was *** oil churning torque was measured at different speeds and *** results from the analytical,simulation,and experimental models agreed *** experimental results validated the analytical model and CFD *** research provides a practical method for calculating the churning loss and serves as guidance for future optimization of churning loss reduction.

关键词： Motor pump Wet motor Churning loss Analytical model Computational fluid dynamics(CFD)

Underwater Terrain Image Stitching Based on Spatial Gradient Feature Block

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Computers, Materials & Continua 2022年第8期72卷 4157-4171页

作者： zhenzhou Wang Jiashuo Li Xiang Wang Xuanhao Niu School of Information Science and Engineering Hebei University of Science and TechnologyShijiazhuang050018China Case Western Reserve University Cleveland44106USA

At present,underwater terrain images are all strip-shaped small fragment images preprocessed by the side-scan sonar imaging ***,the processed underwater terrain images have inconspicuous and few feature *** order to better realize the stitching of underwater terrain images and solve the problems of slow traditional image stitching speed,we proposed an improved algorithm for underwater terrain image stitching based on spatial gradient feature ***,the spatial gradient fuzzy C-Means algorithm is used to divide the underwater terrain image into feature blocks with the fusion of spatial gradient *** accelerated-KAZE(AKAZE)algorithm is used to combine the feature block information to match the reference image and the target ***,the random sample consensus(RANSAC)is applied to optimize the matching ***,image fusion is performed with the global homography and the optimal seam-line method to improve the accuracy of image overlay *** experimental results show that the proposed method in this paper effectively divides images into feature blocks by combining spatial information and gradient information,which not only solves the problem of stitching failure of underwater terrain images due to unobvious features,and further reduces the sensitivity to noise,but also effectively reduces the iterative calculation in the feature point matching process of the traditional method,and improves the stitching *** and shape warping are significantly eliminated by re-optimizing the overlap of the image.

关键词： Underwater terrain images image stitching feature block fuzzy C-means spatial gradient information A-KAZE

Research on Facial Expression Capture Based on Two-Stage Neural Network

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Computers, Materials & Continua 2022年第9期72卷 4709-4725页

作者： zhenzhou Wang Shao Cui Xiang Wang JiaFeng Tian School of Information Science and Engineering Hebei University of Science and TechnologyShijiazhuang050000China School of Engineering Newcastle UniversityNewcastle Upon TyneNE98United Kingdom

To generate realistic three-dimensional animation of virtual character,capturing real facial expression is the primary *** to diverse facial expressions and complex background,facial landmarks recognized by existing strategies have the problem of deviations and low ***,a method for facial expression capture based on two-stage neural network is proposed in this paper which takes advantage of improved multi-task cascaded convolutional networks(MTCNN)and high-resolution ***,the convolution operation of traditional MTCNN is *** face information in the input image is quickly filtered by feature fusion in the first stage and Octave Convolution instead of the original ones is introduced into in the second stage to enhance the feature extraction ability of the network,which further rejects a large number of false *** model outputs more accurate facial candidate windows for better landmarks recognition and locates the *** the images cropped after face detection are input into high-resolution ***-scale feature fusion is realized by parallel connection of multi-resolution streams,and rich high-resolution heatmaps of facial landmarks are ***,the changes of facial landmarks recognized are tracked in *** expression parameters are extracted and transmitted to Unity3D engine to drive the virtual character’s face,which can realize facial expression synchronous *** experimental results obtained on the WFLW database demonstrate the superiority of the proposed method in terms of accuracy and robustness,especially for diverse expressions and complex *** method can accurately capture facial expression and generate three-dimensional animation effects,making online entertainment and social interaction more immersive in shared virtual space.

关键词： Facial expression capture facial landmarks multi-task cascaded convolutional networks high-resolution network animation generation

An Image Edge Detection Algorithm Based on Multi-Feature Fusion

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Computers, Materials & Continua 2022年第12期73卷 4995-5009页

作者： zhenzhou Wang Kangyang Li Xiang Wang Antonio Lee School of Information Science and Engineering Hebei University of Science and TechnologyShijiazhuang050000China Department of Geophysical Engineering Karadeniz Technical UniversityTrabzon61080Turkey

Edge detection is one of the core steps of image processing and computer *** and fine image edge will make further target detection and semantic segmentation more ***-Nested edge detection(HED)edge detection network has been proved to be a deep-learning network with better performance for edge ***,it is found that when the HED network is used in overlapping complex multi-edge scenarios for automatic object *** will be detected edge incomplete,not smooth and other *** solve these problems,an image edge detection algorithm based on improved HED and feature fusion is *** the one hand,features are extracted using the improved HED network:the HED convolution layer is *** residual variable convolution block is used to replace the normal convolution enhancement model to extract features from edges of different sizes and ***,the empty convolution is used to replace the original pooling layer to expand the receptive field and retain more global information to obtain comprehensive feature *** the other hand,edges are extracted using Otsu algorithm:Otsu-Canny algorithm is used to adaptively adjust the threshold value in the global scene to achieve the edge detection under the optimal threshold ***,the edge extracted by improved HED network and Otsu-Canny algorithm is fused to obtain the final *** results show that on the Berkeley University Data Set(BSDS500)the optimal data set size(ODS)F-measure of the proposed algorithm is 0.793;the average precision(AP)of the algorithm is 0.849;detection speed can reach more than 25 frames per second(FPS),which confirms the effectiveness of the proposed method.

关键词： Computer vision edge detection deep learning feature fusion residual convolution