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arXiv 2103.04159math.NAcs.NAmath.AP
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用于求解拟线性偏微分方程边值问题及一类系数反问题的凸化梯度下降法

The gradient descent method for the convexification to solve boundary value problems of quasi-linear PDEs and a coefficient inverse problem

University of North Carolina at Charlotte(北卡罗来纳大学夏洛特分校)

Thuy T. Le, Loc. H. Nguyen

AI总结:

该研究证明了希尔伯特空间有界开集上严格凸泛函最小化的梯度下降法全局收敛性,结合Carleman权函数凸化框架求解带噪拟线性PDE边值问题与背散射反问题,验证了Lipschitz收敛速率与实际应用价值。

摘要:

我们研究了在希尔伯特空间的有界开集上,针对严格凸泛函最小化的梯度下降法的全局收敛性。与整个希尔伯特空间的情况不同,这类集合下的相关收敛结果此前尚不明确。随后,我们利用该结果建立了一个通用框架,用于数值求解含噪声柯西数据的拟线性偏微分方程(PDE)边值问题。该流程借助Carleman权函数对由给定边值问题导出的代价泛函进行凸化,从而保证上述梯度下降法的收敛性。我们证明了当噪声趋于0时该方法具有全局收敛性,收敛速率为Lipschitz型。接下来,我们将该方法应用于求解一个高度非线性且严重病态的系数反问题,即所谓的背散射反问题,该问题具有诸多实际应用。文中还给出了数值算例。

英文摘要:

We study the global convergence of the gradient descent method of the minimization of strictly convex functionals on an open and bounded set of a Hilbert space. Such results are unknown for this type of sets, unlike the case of the entire Hilbert space. Then, we use our result to establish a general framework to numerically solve boundary value problems for quasi-linear partial differential equations (PDEs) with noisy Cauchy data. The procedure involves the use of Carleman weight functions to convexify a cost functional arising from the given boundary value problem and thus to ensure the convergence of the gradient descent method above. We prove the global convergence of the method as the noise tends to 0. The convergence rate is Lipschitz. Next, we apply this method to solve a highly nonlinear and severely ill-posed coefficient inverse problem, which is the so-called back scattering inverse problem. This problem has many real-world applications. Numerical examples are presented.

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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