arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2011.00078math.DS
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随机Koopman算子的鲁棒逼近

Robust Approximation of the Stochastic Koopman Operator

Mathias Wanner, Igor Mezić

摘要:

我们分析了基于动态模式分解(DMD)的随机Koopman算子的随机动力系统的动力学或可观测量受到噪声的影响的近似的性能。对于许多DMD算法,噪声的存在可以在DMD算子中引入偏差,导致动力学的差的近似。特别是,使用时间延迟的观测量,如汉克尔DMD的方法,是有偏见的动态时,是随机的。我们介绍了一种新的,强大的DMD算法,可以近似的随机Koopman算子,尽管存在噪声。然后,我们演示了如何将该算法应用于时间延迟的观测量,这使我们能够从一个单一的观察生成一个Krylov子空间。这使我们能够使用在单个轨迹上测量的单个可观测值来计算随机Koopman算子的实现。我们测试的性能的算法在几个例子。

英文摘要:

We analyze the performance of Dynamic Mode Decomposition (DMD)-based approximations of the stochastic Koopman operator for random dynamical systems where either the dynamics or observables are affected by noise. For many DMD algorithms, the presence of noise can introduce a bias in the DMD operator, leading to poor approximations of the dynamics. In particular, methods using time delayed observables, such as Hankel DMD, are biased when the dynamics are random. We introduce a new, robust DMD algorithm that can approximate the stochastic Koopman operator despite the presence of noise. We then demonstrate how this algorithm can be applied to time delayed observables, which allows us to generate a Krylov subspace from a single observable. This allows us to compute a realization of the stochastic Koopman operator using a single observable measured over a single trajectory. We test the performance of the algorithms over several examples.

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