arXiv:2412.02215cs.LGcs.AI2024-12被引 10

从真实世界数据中恢复隐式物理模型,解决采样率低与扰动时间误差问题。

Recovering implicit physics model under real-world constraints

  • 基于液态时间常数神经网络,自动处理低采样率下的动态建模。
  • 在四个基准系统上比现有方法更准确恢复隐式物理模型系数。
  • 适用于医疗等实际场景,可容忍传感器时间不同步误差。

从真实世界数据中恢复由物理驱动的模型(即底层动力系统的控制方程)是近期研究热点。现有方法大多依赖高采样率仿真数据或需测量所有系统变量,难以应用于真实场景;且通常假设外部扰动的时间戳已知且无误差,忽略了传感器时间不同步或人工报告误差。本文提出一种基于液态时间常数神经网络(LTC-NN)的新架构,利用LTC-NN节点的自动微分特性克服低采样率问题;隐藏层中输入依赖的时间常数构建了大规模隐式物理动态搜索空间;基于物理模型求解器的数据重建损失引导寻找正确的隐式动力学;密集层中的丢弃正则化确保提取最稀疏模型。为应对扰动时间误差,引入密集层节点搜索使重建损失最低的输入偏移。在四个基准动力系统(三个仿真,一个真实数据)上的实验表明,LTC-NN在恢复隐式物理模型系数方面优于当前最先进的稀疏模型恢复方法。此外,通过八个案例研究(四个仿真、四个临床真实数据)验证了该方法在医疗等实际应用中的有效性。

原文摘要 · Abstract (English)

Recovering a physics-driven model, i.e. a governing set of equations of the underlying dynamical systems, from the real-world data has been of recent interest. Most existing methods either operate on simulation data with unrealistically high sampling rates or require explicit measurements of all system variables, which is not amenable in real-world deployments. Moreover, they assume the timestamps of external perturbations to the physical system are known a priori, without uncertainty, implicitly discounting any sensor time-synchronization or human reporting errors. In this paper, we propose a novel liquid time constant neural network (LTC-NN) based architecture to recover underlying model of physical dynamics from real-world data. The automatic differentiation property of LTC-NN nodes overcomes problems associated with low sampling rates, the input dependent time constant in the forward pass of the hidden layer of LTC-NN nodes creates a massive search space of implicit physical dynamics, the physics model solver based data reconstruction loss guides the search for the correct set of implicit dynamics, and the use of the dropout regularization in the dense layer ensures extraction of the sparsest model. Further, to account for the perturbation timing error, we utilize dense layer nodes to search through input shifts that results in the lowest reconstruction loss. Experiments on four benchmark dynamical systems, three with simulation data and one with the real-world data show that the LTC-NN architecture is more accurate in recovering implicit physics model coefficients than the state-of-the-art sparse model recovery approaches. We also introduce four additional case studies (total eight) on real-life medical examples in simulation and with real-world clinical data to show effectiveness of our approach in recovering underlying model in practice.

物理建模神经网络真实数据稀疏恢复

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