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arXiv 2210.04792math.DS
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Koopman算子的非线性数据驱动逼近

Nonlinear Data-Driven Approximation of the Koopman Operator

Dan Wilson

摘要:

Koopman分析提供了一个通用的框架,从该框架中可以用作用于无限维可观测空间的线性算子来分析非线性动力系统。这个理论框架为广泛使用的动态模式分解算法提供了严格的基础。虽然这种方法已被证明是非常有用的时间序列数据的分析,得到的线性模型通常必须是高阶的,以准确地近似基本上非线性行为。这个问题带来了过度拟合训练数据的固有风险,从而限制了预测能力。相比之下,这项工作探讨了非线性数据驱动的估计Koopman算子的行动的策略。一般策略,产量非线性模型的系统与无控制。随后将得到的非线性方程投影到低秩基上,得到底层动力系统的低阶表示。在这两个计算和实验的例子中,考虑在这项工作中,Koopman算子的线性估计一般只能提供短期的预测可观察到的动态,而可比的非线性估计提供准确的预测,在相当长的时间尺度和复制无限的时间行为,线性预测不能。

英文摘要:

Koopman analysis provides a general framework from which to analyze a nonlinear dynamical system in terms of a linear operator acting on an infinite-dimensional observable space. This theoretical framework provides a rigorous underpinning for widely used dynamic mode decomposition algorithms. While such methods have proven to be remarkably useful in the analysis of time-series data, the resulting linear models must generally be of high order to accurately approximate fundamentally nonlinear behaviors. This issue poses an inherent risk of overfitting to training data thereby limiting predictive capabilities. By contrast, this work explores strategies for nonlinear data-driven estimation of the action of the Koopman operator. General strategies that yield nonlinear models are presented for systems both with and without control. Subsequent projection of the resulting nonlinear equations onto a low-rank basis yields a low order representation for the underlying dynamical system. In both computational and experimental examples considered in this work, linear estimators of the Koopman operator are generally only able to provide short-term predictions for the observable dynamics while comparable nonlinear estimators provide accurate predictions on substantially longer timescales and replicate infinite-time behaviors that linear predictors cannot.

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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