In this paper, parameters of Coulomb satellite formation process are derived based on two sets of coordinate systems, and the relative motion equations of the formation is obtained by substituting the energy function ...
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ISBN:
(纸本)9781665409841
In this paper, parameters of Coulomb satellite formation process are derived based on two sets of coordinate systems, and the relative motion equations of the formation is obtained by substituting the energy function of the system into the Lagrange equation. A control scheme to stabilize the formation process of Coulomb satellites is designed by combining a Kahnan filter with a LQG controller. At the same time, a signal is designed from the perspective of the attackers so that the residue related value captured by the detector can be maintained in a small range while a significant state estimation error is achieved. At the same time, a coding matrix scheme is proposed from the perspective of the defender to destroy the stealthiness of the attack by properly encoding/decoding the data transmitted/received, so that the attack can be successfully detected. Finally, stealthiness of the false data injection attack and the method of encryption matrix detection are verified through simulation.
Single-pixel Passive Millimeter Wave (PMMW) imaging system has drawn much attention for its low cost and low complexity. Nowadays, researchers put more effort into the study of the single-pixel PMMW imaging technology...
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ISBN:
(纸本)9781538616208
Single-pixel Passive Millimeter Wave (PMMW) imaging system has drawn much attention for its low cost and low complexity. Nowadays, researchers put more effort into the study of the single-pixel PMMW imaging technology as the wide application of Compressive Sensing technology. Previous studies have indicated that the key of the single-pixel imaging technology is the design of coding template. In most studies, a large number of single-templates are applied for coding sampling. These kinds of methods are not suitable for engineering applications due to their low imaging speed. Therefore, a coding method based on quasi cyclic S matrix is proposed, and a novel coding template is designed to improve the imaging speed in this paper. The algorithms of OMP and TVAL3 simulation results in MATLAB verify the effectiveness of the proposed method.
The 2-bit digital anisotropic impedance metasurfaces (MSs) consisting of four types of anisotropic modules and differing by orientation of anisotropy are examined. Modules are coded by the matrix which consists of dig...
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ISBN:
(纸本)9781538627822
The 2-bit digital anisotropic impedance metasurfaces (MSs) consisting of four types of anisotropic modules and differing by orientation of anisotropy are examined. Modules are coded by the matrix which consists of digital bits: "00", "01", "10", and "11". An asymptotic representation of the polarization scattering matrix of digital impedance surface is obtained. A block principle of the construction of 2-bit digital coatings with coding orientation of anisotropy is offered. Monostatic and bistatic RCS for different models of anisotropy are computed and analyzed. The possibilities of considered models of digital MSs for reduction of RCS on co- and cross-polarizations are compared between themselves.
Due to the limitation of high sampling rate and large coding matrix, it often takes a long time to decode and reconstruct millimeter-wave radiometric images, which becomes a difficult problem for Compressed Sensing (C...
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ISBN:
(数字)9781510646629
ISBN:
(纸本)9781510646629;9781510646612
Due to the limitation of high sampling rate and large coding matrix, it often takes a long time to decode and reconstruct millimeter-wave radiometric images, which becomes a difficult problem for Compressed Sensing (CS) theory in the field of millimeter-wave radiometric imaging. In order to effectively reconstruct millimeter-wave images within the framework of block-based CS, the adaptive sampling methods based on visual saliency and block information weight are proposed in this paper. In view of the irrationality of allocating the same amount of encoded data to different image blocks in the traditional block-based CS, both the adaptive sampling method based on visual saliency and local variance weighted adaptive allocation, and the adaptive sampling method based on visual saliency and two-dimensional information entropy weighted adaptive allocation, are put forward and compared with other allocation methods. Some experimental results demonstrate that the proposed method can effectively improve the PSNR value of the reconstructed image. In addition, the reconstructed images with a low sampling rate are also in conformity with human vision.
In order to solve the problem that the period of designing metasurface with specific functions is too long by using electromagnetic simulation software, this paper proposes a metasurface design method based on artific...
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ISBN:
(纸本)9798350353129;9798350353136
In order to solve the problem that the period of designing metasurface with specific functions is too long by using electromagnetic simulation software, this paper proposes a metasurface design method based on artificial neural network, which can accurately predict the far-field pattern. In the training process, the root-mean-square error decreases with the increase of the number of iterations, the minimum root-mean-square error is 0.01, and the training time is 21 s. After the training is completed, the model can quickly predict the far-field pattern according to the coding matrix. The single prediction time of the neural network is 0.0065 s, while the single simulation time of the full-wave simulation software is 4 min, which is far more than that of the neural network. The accuracy of the predicted data is verified by comparing the predicted results with the results of the full-wave simulation. By combining the neural network with particle swarm optimization algorithm, the metasurface coding matrix corresponding to the target pattern can be designed. Compared with the traditional metasurface design method, this design method greatly reduces the design time and solves the problems of time consuming and cost in the traditional design method.
In this paper we review second order homophonic ciphers and their relevance to the three ciphers attributed to Thomas J. Beale. We provide a few examples of such ciphers, to demonstrate how they are encoded and how th...
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