论文标题

动态网络上的反向传播

Backpropagation on Dynamical Networks

论文作者

Tan, Eugene, Corrêa, Débora, Stemler, Thomas, Small, Michael

论文摘要

动态网络是多功能模型,可以描述各种行为,例如同步和反馈。但是,在现实世界中应用这些模型很难在现实世界中使用,因为与连接结构或局部动态有关的先前信息通常是未知的,并且必须从网络状态的时间序列观察结果中推断出来。另外,节点之间耦合相互作用的影响进一步使局部节点动力学的隔离变得复杂。鉴于动态网络与复发性神经网络(RNN)之间的架构相似性,我们提出了一种基于通过时间(BPTT)算法的反向传播的网络推理方法,通常用于训练复发性神经网络。该方法旨在同时推断出纯粹从节点状态观察的连接性结构和局部节点动力学。首先使用神经网络构建局部节点动力学的近似值。通过基于先前构造的本地模型最小化动力网络的预测误差,直到达到收敛,这是与改编的BPTT算法一起回归相应网络权重来回归相应网络权重的。发现该方法在识别洛伦兹,chua和fitzhugh-nagumo振荡器的耦合网络的连通性结构方面是成功的。发现由此产生的本地模型和权重的Freerun预测性能与具有嘈杂初始条件的真实系统相当。该方法还扩展到非惯性网络耦合,例如不对称的负耦合。

Dynamical networks are versatile models that can describe a variety of behaviours such as synchronisation and feedback. However, applying these models in real world contexts is difficult as prior information pertaining to the connectivity structure or local dynamics is often unknown and must be inferred from time series observations of network states. Additionally, the influence of coupling interactions between nodes further complicates the isolation of local node dynamics. Given the architectural similarities between dynamical networks and recurrent neural networks (RNN), we propose a network inference method based on the backpropagation through time (BPTT) algorithm commonly used to train recurrent neural networks. This method aims to simultaneously infer both the connectivity structure and local node dynamics purely from observation of node states. An approximation of local node dynamics is first constructed using a neural network. This is alternated with an adapted BPTT algorithm to regress corresponding network weights by minimising prediction errors of the dynamical network based on the previously constructed local models until convergence is achieved. This method was found to be succesful in identifying the connectivity structure for coupled networks of Lorenz, Chua and FitzHugh-Nagumo oscillators. Freerun prediction performance with the resulting local models and weights was found to be comparable to the true system with noisy initial conditions. The method is also extended to non-conventional network couplings such as asymmetric negative coupling.

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