New Negentropy Optimization Schemes for Blind Signal Extraction of Complex Valued Sources

Blind signal extraction, a hot issue in the field of communication signal processing, aims to retrieve the sources through the optimization of contrast functions. Many contrasts based on higher-order statistics such as kurtosis, usually behave sensitive to outliers. Thus, to achieve robust results, nonlinear functions are utilized as contrasts to approximate the negentropy criterion, which is also a classical metric for non-Gaussianity. However, existing methods generally have a high computational cost, hence leading us to address the problem of efficient optimization of contrast function. More precisely, we design a novel “reference-based” contrast function based on negentropy approximations, and then propose a new family of algorithms (Alg.1 and Alg.2) to maximize it. Simulations confirm the convergence of our method to a separating solution, which is also analyzed in theory. We also validate the theoretic complexity analysis that Alg.2 has a much lower computational cost than Alg.1 and existing optimization methods based on negentropy criterion. Finally, experiments for the separation of single sideband signals illustrate that our method has good prospects in real-world applications

Production of proton-rich nuclei around Z=84-90 in fusion-evaporation reactions

Within the framework of the dinuclear system model, production cross sections of proton-rich nuclei with charged numbers of Z=84-90 are investigated systematically. Possible combinations with the $^{28}$Si, $^{32}$S, $^{40}$Ar bombarding the target nuclides $^{165}$Ho, $^{169}$Tm, $^{170-174}$Yb, $^{175,176}$Lu, $^{174,176-180}$Hf and $^{181}$Ta are analyzed thoroughly. The optimal excitation energies and evaporation channels are proposed to produce the proton-rich nuclei. The systems are feasible to be constructed in experiments. It is found that the neutron shell closure of N=126 is of importance during the evaporation of neutrons. The experimental excitation functions in the $^{40}$Ar induced reactions can be nicely reproduced. The charged particle evaporation is comparable with neutrons in cooling the excited proton-rich nuclei, in particular for the channels with $\alpha$ and proton evaporation. The production cross section increases with the mass asymmetry of colliding systems because of the decrease of the inner fusion barrier. The channels with pure neutron evaporation depend on the isotopic targets. But it is different for the channels with charged particles and more sensitive to the odd-even effect.Comment: 15 pages, 10 figures. arXiv admin note: text overlap with arXiv:0803.1117, arXiv:0707.258

The FEM-Prediction on tensile performance of woven membrane materials under uni and Bi-axial loads

In this study, the mechanical model of the woven PVC-coated membrane materials has been built. By the FEM analysis, it was found out that when tensioned under uni-axial loads, the tensile modulus in the warp and fill direction of woven membrane materials could be predicted nicely, especially after the revision of the properties for the fiber materials. The effect of the tensile moduli of the fiber and the PVC coating materials on the modulus of the woven membrane fabrics has been discussed. It could be consulted that with the proper improvement of the modulus of the fiber materials in the fill direction, the discrepancy between the modulus of woven membrane materials in the warp and fill direction could be reduced to a certain extent. When it comes to the prediction of the modulus of the woven membrane materials under bi-axial loads, large difference could be noticed between the predicted results and the experimental results, especially in warp direction. This was due to the fact that the mechanical analysis model could only show the differences of the geometry configuration between the warp and fill directions. However, the reinforcement of membrane materials in warp direction during weaving and coating processes has been ignored

Artificial intelligence enhances the performance of chaotic baseband wireless communication

Funding Information: This work was supported in part by Shaanxi Provincial Special Support Program for Science and Technology Innovation Leader. Dr Bai was supported in part by China Postdoctoral Science Foundation Funded Project (2020M673349), and Open Research Fund from Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing (2020CP02).Peer reviewedPublisher PD