Based on the theory of coherence, the model of multi-Gaussian Schell-model(MGSM) beams carrying an edge dislocation generated by the MGSM source is introduced. The analytical cross-spectral density of MGSM beams carry...Based on the theory of coherence, the model of multi-Gaussian Schell-model(MGSM) beams carrying an edge dislocation generated by the MGSM source is introduced. The analytical cross-spectral density of MGSM beams carrying an edge dislocation propagating in oceanic turbulence is derived, and used to study the evolution properties of the MGSM beams carrying an edge dislocation. The results indicate that the MGSM beam carrying an edge dislocation propagating in oceanic turbulence will evolve from the profile with two intensity peaks into a flat-topped beam caused by the MGSM source, and the beam will evolve into the Gaussian-like beam due to the influences of oceanic turbulence in the far field.As the propagation distance increases, the MGSM beam carrying an edge dislocation propagating in oceanic turbulence with the larger rate of dissipation of mean-squared temperature(χT) and ratio of temperature to salinity contribution to the refractive index spectrum(?) or the smaller rate of dissipation of kinetic energy per unit mass of fluid(ε) evolves into the flat-topped beam or a Gaussian beam faster.展开更多
With the help of the extended Huygens-Fresnel principle and the short-term mutual coherence function, the analytical formula of short-term average intensity for multi-Gaussian beam （MGB） in the turbulent a^mosphere ...With the help of the extended Huygens-Fresnel principle and the short-term mutual coherence function, the analytical formula of short-term average intensity for multi-Gaussian beam （MGB） in the turbulent a^mosphere has been derived. The intensity in the absence of turbulence and the long-term average intensity in turbulence can both also be expressed in this formula. As special cases, comparisons among short-term average intensity, long-term average intensity, and the intensity in the absence of turbulence for flat topped beam and annular beam are carried out. The effects of the order of MGB, propagation distance and aperture radius on beam spreading are analysed and discussed in detail.展开更多
为了降低无人机(Unmanned Aerial Vehicle,UAV)的能量消耗,提出基于用户流量预测的UAV功耗最小化算法(Power Minimization Algorithm of UAV based on Traffic Prediction of User,PMTP)。PMTP算法先建立关于资源分配、UAV传输功率和用...为了降低无人机(Unmanned Aerial Vehicle,UAV)的能量消耗,提出基于用户流量预测的UAV功耗最小化算法(Power Minimization Algorithm of UAV based on Traffic Prediction of User,PMTP)。PMTP算法先建立关于资源分配、UAV传输功率和用户位置的多目标联合的优化问题。考虑到优化问题的非线性和非凸性,利用块坐标下降法将目标问题拆解成多个子问题,再分步解之,进而获取资源分配、UAV传输功率和用户位置的次优解,并利用高斯过程回归算法预测流量。通过仿真实验分析PMTP算法在预测流量的准确性、用户平均传输速率以及UAV能耗方面的性能。仿真结果表明,利用高斯过程回归方法能准确度地预测用户流量。PMTP算法提升了用户平均传输速率。在带宽为50MHz、10个用户的平均传输速率达到250Mbps。相比于Maximum power和Random算法,PMTP算法降低了UAV的能耗。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11604038,11875096,and 11404048)the Fundamental Research Funds for the Central Universities,China(Grant Nos.3132019182 and 3132019184)
文摘Based on the theory of coherence, the model of multi-Gaussian Schell-model(MGSM) beams carrying an edge dislocation generated by the MGSM source is introduced. The analytical cross-spectral density of MGSM beams carrying an edge dislocation propagating in oceanic turbulence is derived, and used to study the evolution properties of the MGSM beams carrying an edge dislocation. The results indicate that the MGSM beam carrying an edge dislocation propagating in oceanic turbulence will evolve from the profile with two intensity peaks into a flat-topped beam caused by the MGSM source, and the beam will evolve into the Gaussian-like beam due to the influences of oceanic turbulence in the far field.As the propagation distance increases, the MGSM beam carrying an edge dislocation propagating in oceanic turbulence with the larger rate of dissipation of mean-squared temperature(χT) and ratio of temperature to salinity contribution to the refractive index spectrum(?) or the smaller rate of dissipation of kinetic energy per unit mass of fluid(ε) evolves into the flat-topped beam or a Gaussian beam faster.
文摘With the help of the extended Huygens-Fresnel principle and the short-term mutual coherence function, the analytical formula of short-term average intensity for multi-Gaussian beam （MGB） in the turbulent a^mosphere has been derived. The intensity in the absence of turbulence and the long-term average intensity in turbulence can both also be expressed in this formula. As special cases, comparisons among short-term average intensity, long-term average intensity, and the intensity in the absence of turbulence for flat topped beam and annular beam are carried out. The effects of the order of MGB, propagation distance and aperture radius on beam spreading are analysed and discussed in detail.
文摘为了降低无人机(Unmanned Aerial Vehicle,UAV)的能量消耗,提出基于用户流量预测的UAV功耗最小化算法(Power Minimization Algorithm of UAV based on Traffic Prediction of User,PMTP)。PMTP算法先建立关于资源分配、UAV传输功率和用户位置的多目标联合的优化问题。考虑到优化问题的非线性和非凸性,利用块坐标下降法将目标问题拆解成多个子问题,再分步解之,进而获取资源分配、UAV传输功率和用户位置的次优解,并利用高斯过程回归算法预测流量。通过仿真实验分析PMTP算法在预测流量的准确性、用户平均传输速率以及UAV能耗方面的性能。仿真结果表明,利用高斯过程回归方法能准确度地预测用户流量。PMTP算法提升了用户平均传输速率。在带宽为50MHz、10个用户的平均传输速率达到250Mbps。相比于Maximum power和Random算法,PMTP算法降低了UAV的能耗。
