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arXiv 1603.04036math.AP
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分数阶Helmholtz方程逆散射问题的Infinite-dimensional贝叶斯方法

Infinite-dimensional Bayesian approach for inverse scattering problems of a fractional Helmholtz equation

Junxiong Jia, Shigang Yu, Jigen Peng, Jinghuai Gao

摘要:

本文研究了一种新的描述波在衰减介质中传播的波动方程。本文第一部分从时域空间分数阶波动方程出发,推导出频域分数阶Helmholtz方程。根据物理解释,该模型可以分为两个独立的模型:损耗主导模型和色散主导模型。对于损耗主导模型(整数阶和分数阶混合椭圆型方程),建立了适定性理论,并建立了散射场相对于散射体的Lipschitz连续性。由于色散主导模型(整数阶和分数阶混合椭圆型方程组)的复杂性,我们只提供了足够小波数的适定性结果。在本文的第二部分中,我们推广了无限维的贝叶斯逆理论,允许一部分噪声依赖于目标函数(需要估计的函数)。证明了当模型降阶误差和白噪声均为零时,估计函数趋于真函数。最后,将我们的理论应用于具有吸收边界条件的损失控制模型。

英文摘要:

In this paper, we focus on a new wave equation described wave propagation in the attenuation medium. In the first part of this paper, based on the time-domain space fractional wave equation, we formulate the frequency-domain equation named as fractional Helmholtz equation. According to the physical interpretations, this new model could be divided into two separate models: loss-dominated model and dispersion-dominated model. For the loss-dominated model (it is an integer- and fractional-order mixed elliptic equation), a well-posedness theory has been established and the Lipschitz continuity of the scattering field with respect to the scatterer has also been established.Because the complexity of the dispersion-dominated model (it is an integer- and fractional-order mixed elliptic system), we only provide a well-posedness result for sufficiently small wavenumber. In the second part of this paper, we generalize the Bayesian inverse theory in infinite-dimension to allow a part of the noise depends on the target function (the function needs to be estimated). Then, we prove that the estimated function tends to be the true function if both the model reduction error and the white noise vanish. At last, our theory has been applied to the loss-dominated model with absorbing boundary condition.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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