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arXiv 1901.10568stat.MLcs.LGstat.CO
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用于非线性状态空间模型的随机梯度 MCMC

Stochastic Gradient MCMC for Nonlinear State Space Models

University of Washington(华盛顿大学);Lancaster University(兰卡斯特大学);Stanford University(斯坦福大学)

Christopher Aicher, Srshti Putcha, Christopher Nemeth, Paul Fearnhead, Emily B. Fox

AI总结:

本文针对非线性非高斯状态空间模型在长时间序列上的推断难题,结合粒子方法与缓冲随机梯度估计扩展随机梯度 MCMC,并给出误差界及实验验证。

摘要:

状态空间模型(SSM)通过潜在随机过程为复杂时间序列建模提供了灵活框架。非线性、非高斯 SSM 的推断通常采用粒子方法处理,但这类方法难以扩展到长时间序列。挑战有两方面:不仅计算量如线性情形一样随时间线性增长,而且粒子滤波还会随着序列变长而出现日益严重的粒子退化。随机梯度 MCMC 方法已被用于扩展有限状态隐马尔可夫模型和线性 SSM 的贝叶斯推断,其利用缓冲随机梯度估计来考虑时间依赖关系。我们使用粒子方法将这些随机梯度估计器扩展到非线性 SSM。对于在潜在过程上具有对数凹性的非线性 SSM,我们给出了同时考虑缓冲误差和粒子误差的误差界。我们通过随机梯度 MCMC 评估所提出的粒子缓冲随机梯度,在长序列合成数据和分钟级金融收益数据上进行推断,证明了这类方法的重要性。

英文摘要:

State space models (SSMs) provide a flexible framework for modeling complex time series via a latent stochastic process. Inference for nonlinear, non-Gaussian SSMs is often tackled with particle methods that do not scale well to long time series. The challenge is two-fold: not only do computations scale linearly with time, as in the linear case, but particle filters additionally suffer from increasing particle degeneracy with longer series. Stochastic gradient MCMC methods have been developed to scale Bayesian inference for finite-state hidden Markov models and linear SSMs using buffered stochastic gradient estimates to account for temporal dependencies. We extend these stochastic gradient estimators to nonlinear SSMs using particle methods. We present error bounds that account for both buffering error and particle error in the case of nonlinear SSMs that are log-concave in the latent process. We evaluate our proposed particle buffered stochastic gradient using stochastic gradient MCMC for inference on both long sequential synthetic and minute-resolution financial returns data, demonstrating the importance of this class of methods.

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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