19,699 research outputs found
Anti-dark and Mexican-hat solitons in the Sasa-Satsuma equation on the continuous wave background
In this letter, via the Darboux transformation method we construct new
analytic soliton solutions for the Sasa-Satsuma equation which describes the
femtosecond pulses propagation in a monomode fiber. We reveal that two
different types of femtosecond solitons, i.e., the anti-dark (AD) and
Mexican-hat (MH) solitons, can form on a continuous wave (CW) background, and
numerically study their stability under small initial perturbations. Different
from the common bright and dark solitons, the AD and MH solitons can exhibit
both the resonant and elastic interactions, as well as various
partially/completely inelastic interactions which are composed of such two
fundamental interactions. In addition, we find that the energy exchange between
some interacting soliton and the CW background may lead to one AD soliton
changing into an MH one, or one MH soliton into an AD one.Comment: 12 pages, 6 figure
High-Resolution Remotely Sensed Small Target Detection by Imitating Fly Visual Perception Mechanism
The difficulty and limitation of small target detection methods for high-resolution remote sensing data have been a recent research hot spot. Inspired by the information capture and processing theory of fly visual system, this paper endeavors to construct a characterized model of information perception and make use of the advantages of fast and accurate small target detection under complex varied nature environment. The proposed model forms a theoretical basis of small target detection for high-resolution remote sensing data. After the comparison of prevailing simulation mechanism behind fly visual systems, we propose a fly-imitated visual system method of information processing for high-resolution remote sensing data. A small target detector and corresponding detection algorithm are designed by simulating the mechanism of information acquisition, compression, and fusion of fly visual system and the function of pool cell and the character of nonlinear self-adaption. Experiments verify the feasibility and rationality of the proposed small target detection model and fly-imitated visual perception method
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