arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2106.03023stat.MEstat.APstat.ML
收藏

实值时间序列的上下文树加权:基于分层混合模型的贝叶斯推断

Context-tree weighting for real-valued time series: Bayesian inference with hierarchical mixture models

Ioannis Papageorgiou, Ioannis Kontoyiannis

AI总结:

本文提出基于上下文树的分层贝叶斯混合建模框架,将离散上下文状态与底层实值时间序列模型关联,并扩展上下文树加权实现高效精确推断,在自回归模型下构建的非线性AR混合模型在模拟与真实实验中优于现有先进方法。

摘要:

实值时间序列在科学与工程中无处不在。本文开发了一个通用的分层贝叶斯建模框架,用于构建时间序列的混合模型。该开发部分基于上下文树的使用,并包含一系列用于学习与推断的有效算法工具。对每个样本提取一个离散上下文(或“状态”),该上下文由紧邻其之前的部分最近观测值的离散化版本组成。所有相关上下文的集合被表示为一棵离散上下文树。在底层,每个上下文状态(即树的每个叶节点)关联一个不同的实值时间序列模型。这定义了一个非常通用的框架,可以与任何现有模型类结合使用,以构建灵活且可解释的混合模型。扩展上下文树加权的思想可得到允许在该设定下进行高效、精确贝叶斯推断的算法。当底层使用自回归(AR)模型时,详细展示了该通用框架的效用,由此得到一个非线性AR混合模型。在模拟和真实世界实验中,相关方法被发现优于多种最先进的技术。

英文摘要:

Real-valued time series are ubiquitous in the sciences and engineering. In this work, a general, hierarchical Bayesian modelling framework is developed for building mixture models for times series. This development is based, in part, on the use of context trees, and it includes a collection of effective algorithmic tools for learning and inference. A discrete context (or 'state') is extracted for each sample, consisting of a discretised version of some of the most recent observations preceding it. The set of all relevant contexts are represented as a discrete context-tree. At the bottom level, a different real-valued time series model is associated with each context-state, i.e., with each leaf of the tree. This defines a very general framework that can be used in conjunction with any existing model class to build flexible and interpretable mixture models. Extending the idea of context-tree weighting leads to algorithms that allow for efficient, exact Bayesian inference in this setting. The utility of the general framework is illustrated in detail when autoregressive (AR) models are used at the bottom level, resulting in a nonlinear AR mixture model. The associated methods are found to outperform several state-of-the-art techniques on simulated and real-world experiments.

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。

↑