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581.
Xuhui Zheng Ziyan Liu Jing Liang Yingyu Wu Yunlei Chen Qian Zhang 《Entropy (Basel, Switzerland)》2022,24(2)
Channel estimation is a challenging task in a millimeter-wave (mm Wave) massive multiple-input multiple-output (MIMO) system. The existing deep learning scheme, which learns the mapping from the input to the target channel, has great difficulty in estimating the exact channel state information (CSI). In this paper, we consider the quantized received measurements as a low-resolution image, and we adopt the deep learning-based image super-resolution technique to reconstruct the mm Wave channel. Specifically, we exploit a state-of-the-art channel estimation framework based on residual learning and multi-path feature fusion (RL-MFF-Net). Firstly, residual learning makes the channel estimator focus on learning high-frequency residual information between the quantized received measurements and the mm Wave channel, while abundant low-frequency information is bypassed through skip connections. Moreover, to address the estimator’s gradient dispersion problem, a dense connection is added to the residual blocks to ensure the maximum information flow between the layers. Furthermore, the underlying mm Wave channel local features extracted from different residual blocks are preserved by multi-path feature fusion. The simulation results demonstrate that the proposed scheme outperforms traditional methods as well as existing deep learning methods, especially in the low signal-to-noise-ration (SNR) region. 相似文献
582.
Takashi Fukutomi Hiroki Oomori Yoshibumi Sugito 《Journal of polymer science. Part A, Polymer chemistry》1996,34(13):2729-2735
Poly(methyl methacrylate) microgels covered with poly(hydroxyethyl methacrylate) thin layer was dispersed in poly(vinyl alcohol) matrix. Homogeneous and regular arrangement of the microgel particles was suggested by Bragg diffraction for the films prepared by varying the PVA/microgel ratio (from 6/4 to 3/7 (w/w)). It was proved that the regular arrangement and connection of the microgels by seeded polymerization in poly(vinyl alcohol) were possible. © 1996 John Wiley & Sons, Inc. 相似文献
583.
584.
A generalized Yang-Mills model, which contains, besides the vector part
Vμ, also a scalar part S, is constructed and the dynamical breaking of gauge symmetry in the model is also discussed. It is shown, in terms of Nambu-Jona-Lasinio (NJL) mechanism, that the gauge symmetry breaking can be realized
dynamically in the generalized Yang-Mills model. The combination of the
generalized Yang-Mills model and the NJL mechanism provides a way to overcome
the difficulties related to the Higgs field and the Higgs mechanism in the
usual spontaneous symmetry breaking theory. 相似文献
585.
采用有限元程序ABAQUS进行仿真分析,探讨了钢框架节点的非线性连接性能。针对几种典型节点,包括焊接连接、外伸式端板螺栓连接、平齐式端板螺栓连接、双腹板顶底角钢连接等,分别建立了相应的精化有限元分析模型,实现了结构非线性行为的真实再现和连接性能的准确评估。数值结果还给出了钢框架节点的弯矩-相对转角、弯矩-剪切转角及弯矩-节点转角三种关系曲线,并针对弯矩-节点转角曲线进行了回归分析,从而得到了四种钢框架节点的弯矩-节点转角关系式。建立的有限元分析模型可真实地模拟钢框架节点的非线性行为,分析得到了半刚性节点弯矩-转角关系的一般规律,可为钢框架梁柱连接节点的计算理论和设计方法提供重要参考和依据。 相似文献
586.
Geometric structures of Cosserat or micropolar continuum are discussed based on geometric objects in a non-Riemannian space. A microrotation is described in a microscopic level than a macroscopic displacement level. In this case, a microscopic rotation can be expressed as a nonlocal internal variable attached to each point in a generalized Finsler space. Such non-local hierarchy is geometrically realized by using a second-order vector bundle viewpoint. Then, two kinds of torsion tensor in the second-order vector bundle are obtained. One is characterized by the macroscopic displacement. The other is characterized by the microscopic rotation. These torsion tensors are equivalent to nonintegrability conditions for multivalued macroscopic displacement and microscopic rotation. Especially, a path dependency of the displacement and the microscopic rotation is represented by a non-vanishing condition of torsion tensors. Moreover, the concept of non-locality of the Finsler geometry implies that the approach of higher-order geometry is applicable to a finite deformation in nonlinear mechanics. The singularity given by the multivalued function is also described as a boundary value problem. An application of the generalized Finsler geometry to a gradient theory is also discussed. 相似文献
587.
In this paper, we introduce a modified small-world network added with
new links with preferential connection instead of adding randomly,
then we apply Bak-Sneppen (BS) evolution model on this network.
Several dynamical character of the model such as the evolution
graph, f0 avalanche, the critical exponent D and τ, and
the distribution of mutation times of all the nodes, show
particular behaviors different from those of the model based on
the regular network and the small-world network. 相似文献
588.
Susan A. van Aardt Christoph Brause Alewyn P. Burger Marietjie Frick Arnfried Kemnitz Ingo Schiermeyer 《Discrete Mathematics》2017,340(11):2673-2677
An edge-coloured graph is called properly connected if any two vertices are connected by a path whose edges are properly coloured. The proper connection number of a connected graph denoted by , is the smallest number of colours that are needed in order to make properly connected. Our main result is the following: Let be a connected graph of order and . If , then except when and where and 相似文献
589.
In this paper, the classical Galois theory to the H*-Galois case is developed. Let H be a semisimple and cosemisimple Hopf algebra over a field k, A a left H-module algebra,and A/AHa right H*-Galois extension. The authors prove that, if AHis a separable kalgebra, then for any right coideal subalgebra B of H, the B-invariants A~B= {a ∈ A |b · a = ε(b)a, b∈ B} is a separable k-algebra. They also establish a Galois connection between right coideal subalgebras of H and separable subalgebras of A containing AHas in the classical case. The results are applied to the case H =(kG)*for a finite group G to get a Galois 1-1 correspondence. 相似文献
590.
Zhang Rongye 《应用数学和力学(英文版)》1996,17(8):751-764
In this paper we discuss Newtonian Mechanics on Kahler Manifold, and also givefoe complex mathematical aspects of Newton’s law, the law of kinetic energy, the lawof kinetic quantity,the equation of motion and the "general equation of dynamics",and so on. 相似文献