您的检索：
学者姓名：王民
精炼检索结果：
年份
成果类型
收录类型
来源
综合
曾用名
合作者
语言
清除所有精炼条件
摘要 ：
With the development of space technology, the large scale space deployable antennas gradually become one of the key research themes of research. The basic requirements for large scale satellite antennas are the characteristics of light in weight and high in profile accuracy. The low-frequency and large-amplitude vibration of the large scale antennas is easily excited when working in an environment with zero gravity. In order to suppress the vibration of large scale deployable satellite antenna, a new type of damping mechanism with resetting capability is presented to improve the ability of vibration energy consumption and ensure the dynamic characteristics of the radial rib structure containing the presented profile accuracy of the antenna. The rod making up the deployment mechanism of the antennas is divided into two parts which connected by using the shape memory alloy (SMA) wires through guiding mechanism. Meanwhile, a metal rubber is fixed and pressed between two parts of the rod by SMA wires. The ability of the friction energy dissipation of the metal rubber is utilized to suppress the axial vibration of the rods. The super elasticity of the SMA wires is used to provide the restoring force for ensuring the dimensional stability of the rod. In this paper, the design principle of the axial self-resetting damping structure is introduced in detail. And, the dynamic characteristics of the radial rib structure containing the presented damping mechanism are investigated by using the software ANSYS. The simulation results show that the vibration amplitude of the radial rib of antennas has been reduced significantly. © Published under licence by IOP Publishing Ltd.
关键词 ：
Scales (weighing instruments) Scales (weighing instruments) Energy utilization Energy utilization Rubber Rubber Energy dissipation Energy dissipation Satellite antennas Satellite antennas Dynamics Dynamics Vibration control Vibration control Satellites Satellites Wire Wire Damping Damping Shape-memory alloy Shape-memory alloy
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | Wang, Min , Liu, Jiaxing , Liu, Qinda et al. Research on Damping Mechanism with Resetting Capability for Axial Vibration Control of Satellite Antenna [C] . 2021 . |
| MLA | Wang, Min et al. "Research on Damping Mechanism with Resetting Capability for Axial Vibration Control of Satellite Antenna" . (2021) . |
| APA | Wang, Min , Liu, Jiaxing , Liu, Qinda , Zhao, Tingting , Zhang, Yunfei . Research on Damping Mechanism with Resetting Capability for Axial Vibration Control of Satellite Antenna . (2021) . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
高速滚珠丝杠副非赫兹接触应力计算
关键词 ：
接触应力 接触应力 最小余能原理 最小余能原理 赫兹接触 赫兹接触 共轭梯度法 共轭梯度法 滚珠丝杠副 滚珠丝杠副
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | 王民 , 孙铁伟 , 董朝阳 et al. 高速滚珠丝杠副非赫兹接触应力计算 [J]. | 王民 , 2021 , 53 (2) : 178-186 . |
| MLA | 王民 et al. "高速滚珠丝杠副非赫兹接触应力计算" . | 王民 53 . 2 (2021) : 178-186 . |
| APA | 王民 , 孙铁伟 , 董朝阳 , 孔德顺 , 高相胜 , 工程科学与技术 . 高速滚珠丝杠副非赫兹接触应力计算 . | 王民 , 2021 , 53 (2) , 178-186 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
It is well-known that second-order optimizer can accelerate the training of deep neural networks, however, the huge computation cost of second-order optimization makes it impractical to apply in real practice. In order to reduce the cost, many methods have been proposed to approximate a second-order matrix. Inspired by KFAC, we propose a novel Trace-based Hardware-driven layer-ORiented Natural Gradient Descent Computation method, called THOR, to make the second-order optimization applicable in the real application models. Specifically, we gradually increase the update interval and use the matrix trace to determine which blocks of Fisher Information Matrix (FIM) need to be updated. Moreover, by resorting the power of hardware, we have designed a hardware-driven approximation method for computing FIM to achieve better performance. To demonstrate the effectiveness of THOR, we have conducted extensive experiments. The results show that training ResNet-50 on ImageNet with THOR only takes 66.7 minutes to achieve a top-1 accuracy of 75.9 % under an 8 Ascend 910 environment with MindSpore, a new deep learning computing framework. Moreover, with more computational resources, THOR can only takes 2.7 minutes to 75.9 % with 256 Ascend 910.
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | Chen, Mengyun , Gao, Kaixin , Liu, Xiaolei et al. THOR, Trace-Based Hardware-Driven Layer-Oriented Natural Gradient Descent Computation [C] . 2021 : 7046-7054 . |
| MLA | Chen, Mengyun et al. "THOR, Trace-Based Hardware-Driven Layer-Oriented Natural Gradient Descent Computation" . (2021) : 7046-7054 . |
| APA | Chen, Mengyun , Gao, Kaixin , Liu, Xiaolei , Wang, Zidong , Ni, Ningxi , Zhang, Qian et al. THOR, Trace-Based Hardware-Driven Layer-Oriented Natural Gradient Descent Computation . (2021) : 7046-7054 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
Mild cognitive impairment (MCI) detection using magnetic resonance image (MRI), plays a crucial role in the treatment of dementia disease at an early stage. Deep learning architecture produces impressive results in such research. Algorithms require a large number of annotated datasets for training the model. In this study, we overcome this issue by using layer-wise transfer learning as well as tissue segmentation of brain images to diagnose the early stage of Alzheimer's disease (AD). In layer-wise transfer learning, we used the VGG architecture family with pre-trained weights. The proposed model segregates between normal control (NC), the early mild cognitive impairment (EMCI), the late mild cognitive impairment (LMCI), and the AD. In this paper, 85 NC patients, 70 EMCI, 70 LMCI, and 75 AD patients access form the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Tissue segmentation was applied on each subject to extract the gray matter (GM) tissue. In order to check the validity, the proposed method is tested on preprocessing data and achieved the highest rates of the classification accuracy on AD vs NC is 98.73%, also distinguish between EMCI vs LMCI patients testing accuracy 83.72%, whereas remaining classes accuracy is more than 80%. Finally, we provide a comparative analysis with other studies which shows that the proposed model outperformed the state-of-the-art models in terms of testing accuracy.
关键词 ：
Alzheimer’s disease Alzheimer’s disease Early diagnosis Early diagnosis Image classification Image classification Transfer learning Transfer learning
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | Mehmood Atif , Yang Shuyuan , Feng Zhixi et al. A Transfer Learning Approach for Early Diagnosis of Alzheimer's Disease on MRI Images. [J]. | Neuroscience , 2021 , 460 : 43-52 . |
| MLA | Mehmood Atif et al. "A Transfer Learning Approach for Early Diagnosis of Alzheimer's Disease on MRI Images." . | Neuroscience 460 (2021) : 43-52 . |
| APA | Mehmood Atif , Yang Shuyuan , Feng Zhixi , Wang Min , Ahmad Al Smadi , Khan Rizwan et al. A Transfer Learning Approach for Early Diagnosis of Alzheimer's Disease on MRI Images. . | Neuroscience , 2021 , 460 , 43-52 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
When the stress wave propagates through rock mass with different wave impedances on two sides. It shows different reflection tendencies compared with the traditional study of wave propagation. A characteristic line method combined with the displacement discontinuity model was proposed to study the wave reflection through such rock mass. The effects of incident frequency, joint stiffness and wave impedance ratio on the reflection coefficient were discussed. The results show that the reflection coefficient increases as the wave impedance ratio increases. The traditional study of wave reflection can be regarded as a special case of the present study when the wave impedance ratio equals 1.0. Moreover, the difference of reflection coefficients decreases as the incident frequency increases, while increases as the joint stiffness and wave impedance ratio increase when the wave impedance ratio is larger than 1.0. When the wave impedance ratio is smaller than 1.0, the difference of reflection coefficients increases firstly and then decreases with the increase of incident frequency and joint stiffness, while decreases as the wave impedance ratio increases. For the cases of large incident frequency or small joint stiffness, the effects of wave impedance ratio can be neglected for the approximated prediction of wave reflection.
关键词 ：
jointed rock mass jointed rock mass > > wave impedance ratio wave impedance ratio reflection coefficient<break reflection coefficient<break amplitude attenuation amplitude attenuation Wave reflection Wave reflection
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | Wang, L. J. , Wu, C. Q. , Fan, L. F. et al. Investigation of wave reflection at the joint with different wave impedances on two sides [J]. | WAVES IN RANDOM AND COMPLEX MEDIA , 2021 . |
| MLA | Wang, L. J. et al. "Investigation of wave reflection at the joint with different wave impedances on two sides" . | WAVES IN RANDOM AND COMPLEX MEDIA (2021) . |
| APA | Wang, L. J. , Wu, C. Q. , Fan, L. F. , Wang, M. . Investigation of wave reflection at the joint with different wave impedances on two sides . | WAVES IN RANDOM AND COMPLEX MEDIA , 2021 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
Second-order optimization methods have the ability to accelerate convergence by modifying the gradient through the curvature matrix. There have been many attempts to use second-order optimization methods for training deep neural networks. In this work, inspired by diagonal approximations and factored approximations such as Kronecker-factored Approximate Curvature (KFAC), we propose a new approximation to the Fisher information matrix (FIM) called Trace-restricted Kronecker-factored Approximate Curvature (TKFAC), which can hold the certain trace relationship between the exact and the approximate FIM. In TKFAC, we decompose each block of the approximate FIM as a Kronecker product of two smaller matrices and scaled by a coefficient related to trace. We theoretically analyze TKFAC's approximation error and give an upper bound of it. We also propose a new damping technique for TKFAC on convolutional neural networks to maintain the superiority of second-order optimization methods during training. Experiments show that our method has better performance compared with several state-of-the-art algorithms on some deep network architectures.
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | Gao, Kaixin , Liu, Xiaolei , Huang, Zhenghai et al. A Trace-restricted Kronecker-factored Approximation to Natural Gradient [C] . 2021 : 7519-7527 . |
| MLA | Gao, Kaixin et al. "A Trace-restricted Kronecker-factored Approximation to Natural Gradient" . (2021) : 7519-7527 . |
| APA | Gao, Kaixin , Liu, Xiaolei , Huang, Zhenghai , Wang, Min , Wang, Zidong , Xu, Dachuan et al. A Trace-restricted Kronecker-factored Approximation to Natural Gradient . (2021) : 7519-7527 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
Thermal error of ball screws seriously affects the machining precision of computerized numerical control (CNC) machine tools especially in high speed and precision machining. Compensation technology is one of the most effective methods to address the thermal issue, and the effect of compensation depends on the accuracy and robustness of the thermal error model. Traditional modeling approaches have major challenges in time series thermal error prediction. In this paper, a novel thermal error model based on long short-term memory (LSTM) neural network and particle swarm optimization (PSO) algorithm is proposed. A data-driven model based on LSTM neural network is established according to the time series collected data. The hyperparameters of LSTM neural network are optimized by PSO, and then a PSO-LSTM model is established to precisely predict the thermal error of ball screws. In order to verify the effectiveness and robustness of the proposed model, two thermal characteristic experiments based on step and random speed are conducted on a self-designed test bench. The results show that the PSO-LSTM model has higher accuracy compared with the radial basis function (RBF) model and back propagation (BP) model with high robustness. The proposed method can be implemented to predict the thermal error of ball screws and provide a foundation for thermal error compensation.
关键词 ：
Thermal error Thermal error PSO-LSTM PSO-LSTM Data-driven Data-driven Modeling Modeling Ball screw Ball screw
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | Gao, Xiangsheng , Guo, Yueyang , Hanson, Dzonu Ambrose et al. Thermal error prediction of ball screws based on PSO-LSTM [J]. | INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY , 2021 , 116 (5-6) : 1721-1735 . |
| MLA | Gao, Xiangsheng et al. "Thermal error prediction of ball screws based on PSO-LSTM" . | INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 116 . 5-6 (2021) : 1721-1735 . |
| APA | Gao, Xiangsheng , Guo, Yueyang , Hanson, Dzonu Ambrose , Liu, Zhihao , Wang, Min , Zan, Tao . Thermal error prediction of ball screws based on PSO-LSTM . | INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY , 2021 , 116 (5-6) , 1721-1735 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
A new analytical method for the modeling of the thermal contact resistance of ball screws considering the load distribution of balls is proposed in this research. The load on balls is analyzed by the force analysis of ball screws, and then, the thermal contact resistance is obtained by the minimum excess principle and Majumdar-Bhushan (MB) fractal theory. The proposed method is validated by experimental results. The comparison with experimental and former results indicates that it is an effective method to evaluate the thermal contact resistance of ball screws. On that basis, effects of axial load, axial pretension, and geometry error of balls are discussed. It is concluded that the thermal contact resistance of ball screws increases along with axial load increase. The load on balls all decreases with axial pretension increase, and the thermal contact resistance of ball screws decreases with the axial pretension increase as well. When the axial load is applied on the nut in an axial-pretension ball screw, the load distribution in Nut A or B becomes less homogenized when the nut moves from nut position parameter xi = 0 to 1. When the nut moves to xi = 0.25, the thermal contact resistance will reach a minimum value, and it gets a maximum value at the nut position xi = 1. The interval range of load and thermal contact resistance are obtained via uncertain analysis. It is concluded that the geometry error has much greater effects on the balls far away from the spacer.
关键词 ：
axial load axial load axial pretension axial pretension ball screw ball screw geometry error geometry error load distribution load distribution thermal contact resistance thermal contact resistance
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | Gao, Xiangsheng , Ma, Jiqian , Li, Qi et al. Modeling of Thermal Contact Resistance of Ball Screws Considering the Load Distribution of Balls [J]. | JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS , 2021 , 13 (4) . |
| MLA | Gao, Xiangsheng et al. "Modeling of Thermal Contact Resistance of Ball Screws Considering the Load Distribution of Balls" . | JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS 13 . 4 (2021) . |
| APA | Gao, Xiangsheng , Ma, Jiqian , Li, Qi , Wang, Min , Zan, Tao . Modeling of Thermal Contact Resistance of Ball Screws Considering the Load Distribution of Balls . | JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS , 2021 , 13 (4) . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
A dual-mesh three characteristic lines method was proposed for stress wave propagation through a microdefected rock mass containing a thin-layer filled macrojoint. The dual-mesh three characteristic lines are composed of five basic elements that are used to calculate stress wave propagation at the boundary and the interior of the microdefected rock mass and the left side, interior and right side of the filled macrojoint. The results of the present study were compared with that of available analytical results that do not consider microdefects and do not consider microdefects and macrojoint thickness. The results show that the proposed method can be used to efficiently investigate the effect of microdefects and filled macrojoints on wave propagation. The results also show that the viscosity coefficient in the equivalent viscoelastic model of the microdefected rock mass, the viscosity coefficient in the equivalent viscoelastic model of the filled macrojoint and the thickness of the filled macrojoint have significant effects on stress wave attenuation. The transmission coefficient initially decreases and then increases as the viscosity coefficient in the equivalent viscoelastic model of the microdefected rock mass increases. The transmission coefficient increases and then tends to flatten as the viscosity coefficient in the equivalent viscoelastic model of the filled macrojoint increases. The transmission coefficient decreases as the thickness of the filled macrojoint increases.
关键词 ：
Dual-mesh three characteristic lines method Dual-mesh three characteristic lines method Filled macrojoint Filled macrojoint Microdefect Microdefect Rock mass Rock mass Stress wave propagation Stress wave propagation
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | Fan, L. F. , Wang, M. , Du, X. L. . Dual-Mesh Three Characteristic Lines Method for Stress Wave Propagation Through a Microdefected Rock Mass with a Thin-Layer Filled Macrojoint [J]. | ROCK MECHANICS AND ROCK ENGINEERING , 2021 . |
| MLA | Fan, L. F. et al. "Dual-Mesh Three Characteristic Lines Method for Stress Wave Propagation Through a Microdefected Rock Mass with a Thin-Layer Filled Macrojoint" . | ROCK MECHANICS AND ROCK ENGINEERING (2021) . |
| APA | Fan, L. F. , Wang, M. , Du, X. L. . Dual-Mesh Three Characteristic Lines Method for Stress Wave Propagation Through a Microdefected Rock Mass with a Thin-Layer Filled Macrojoint . | ROCK MECHANICS AND ROCK ENGINEERING , 2021 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
In this paper we propose and analyze a second order accurate (in time) numerical scheme for the square phase field crystal equation, a gradient flow modeling crystal dynamics at the atomic scale in space but on diffusive scales in time. Its primary difference with the standard phase field crystal model is an introduction of the 4-Laplacian term in the free energy potential, which in turn leads to a much higher degree of nonlinearity. To make the numerical scheme linear while preserving the nonlinear energy stability, we make use of the scalar auxiliary variable (SAV) approach, in which a second order backward differentiation formula is applied in the temporal stencil. Meanwhile, a direct application of the SAV method faces certain difficulties, due to the involvement of the 4-Laplacian term, combined with a derivation of the lower bound of the nonlinear energy functional. In the proposed numerical method, an appropriate decomposition for the physical energy functional is formulated, so that the nonlinear energy part has a well-established global lower bound, and the rest terms lead to constant-coefficient diffusion terms with positive eigenvalues. In turn, the numerical scheme could be very efficiently implemented by constant-coefficient Poisson-like type solvers (via FFT), and energy stability is established by introducing an auxiliary variable, and an optimal rate convergence analysis is provided for the proposed SAV method. A few numerical experiments are also presented, which confirm the efficiency and accuracy of the proposed scheme.
关键词 ：
Energy stability Energy stability Fourier pseudo-spectral approximation Fourier pseudo-spectral approximation Optimal rate convergence analysis Optimal rate convergence analysis Second order BDF stencil Second order BDF stencil Square phase field crystal equation Square phase field crystal equation The Scalar auxiliary variable (SAV)method The Scalar auxiliary variable (SAV)method
引用：
复制并粘贴一种已设定好的引用格式，或利用其中一个链接导入到文献管理软件中。
| GB/T 7714 | Wang, Min , Huang, Qiumei , Wang, Cheng . A Second Order Accurate Scalar Auxiliary Variable (SAV) Numerical Method for the Square Phase Field Crystal Equation [J]. | JOURNAL OF SCIENTIFIC COMPUTING , 2021 , 88 (2) . |
| MLA | Wang, Min et al. "A Second Order Accurate Scalar Auxiliary Variable (SAV) Numerical Method for the Square Phase Field Crystal Equation" . | JOURNAL OF SCIENTIFIC COMPUTING 88 . 2 (2021) . |
| APA | Wang, Min , Huang, Qiumei , Wang, Cheng . A Second Order Accurate Scalar Auxiliary Variable (SAV) Numerical Method for the Square Phase Field Crystal Equation . | JOURNAL OF SCIENTIFIC COMPUTING , 2021 , 88 (2) . |
| 导入链接 | NoteExpress RIS BibTex |
导出
| 数据： |
选中 到 |
| 格式： |
