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arXiv 1104.3073math.STstat.MEstat.TH
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时间序列建模中的特征匹配

Feature Matching in Time Series Modeling

Yingcun Xia, Howell Tong

摘要:

使用时间序列模型来模拟观测到的时间序列有很长的历史。然而,对于这个目标,传统的离散时间动态模型的估计方法经常被发现是想要的。事实上,他们至少在两个方面被典型地误导了:(i)假设有一个真实的模型;(ii)评估估计的有效性,好像假设的模型是真实的。有许多例子表明,当用传统方法拟合时,模型无法捕捉到数据的一些最基本的全球特征,例如具有良好匹配周期的周期、谱密度函数的奇异性(特别是在原点)等。我们认为,这些缺点并不总是由于模型的制定,但传统的拟合方法的不足。毕竟,所有的模型都是错误的,但有些模型是有用的,如果它们适合的话。实际问题变成了如何使模型与数据最佳拟合。因此,在没有真实模型的情况下,我们更喜欢传统模型拟合的替代方法,传统模型拟合通常涉及提前一步的预测误差。我们的主要目标是匹配可观测的时间序列的联合概率分布,包括支撑数据的动态的长期特征,如周期、长记忆等,而不是短期预测。由于没有更好的名称,我们称之为特定目标特征匹配。

英文摘要:

Using a time series model to mimic an observed time series has a long history. However, with regard to this objective, conventional estimation methods for discrete-time dynamical models are frequently found to be wanting. In fact, they are characteristically misguided in at least two respects: (i) assuming that there is a true model; (ii) evaluating the efficacy of the estimation as if the postulated model is true. There are numerous examples of models, when fitted by conventional methods, that fail to capture some of the most basic global features of the data, such as cycles with good matching periods, singularities of spectral density functions (especially at the origin) and others. We argue that the shortcomings need not always be due to the model formulation but the inadequacy of the conventional fitting methods. After all, all models are wrong, but some are useful if they are fitted properly. The practical issue becomes one of how to best fit the model to data. Thus, in the absence of a true model, we prefer an alternative approach to conventional model fitting that typically involves one-step-ahead prediction errors. Our primary aim is to match the joint probability distribution of the observable time series, including long-term features of the dynamics that underpin the data, such as cycles, long memory and others, rather than short-term prediction. For want of a better name, we call this specific aim feature matching.

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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