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arXiv 2001.06966math.STstat.TH
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高斯和惠特尔李克图的近似及其在频域估计中的应用

Reconciling the Gaussian and Whittle Likelihood with an application to estimation in the frequency domain

Suhasini Subba Rao, Junho Yang

摘要:

在时间序列分析中,时域和频域方法之间存在明显的二分法。本文的目的是绘制频率和时域方法之间的联系。我们的重点将是调和高斯似然和惠特尔似然。我们得到一个精确的,可解释的,二阶平稳时间序列的高斯和惠特尔之间的可能性的界限。该推导基于获得与时间序列的离散傅里叶变换双正交的变换。这样的变换产生了一个新的分解的逆Toeplitz矩阵,并使高斯似然的频域内的表示。我们表明,高斯和惠特尔之间的差异可能是由于省略的最佳线性预测域外的观察周期图与惠特尔可能性。在此基础上,我们得到了一个近似的差异高斯和Whittle似然的最佳拟合,有穷级自回归参数。这些近似被用来定义两个新的频域准似然准则。我们表明,这些新的标准可以产生一个更好的近似的谱发散标准相比,高斯和惠特尔似然。在模拟中,我们证明了所提出的估计具有令人满意的有限样本性质。

英文摘要:

In time series analysis there is an apparent dichotomy between time and frequency domain methods. The aim of this paper is to draw connections between frequency and time domain methods. Our focus will be on reconciling the Gaussian likelihood and the Whittle likelihood. We derive an exact, interpretable, bound between the Gaussian and Whittle likelihood of a second order stationary time series. The derivation is based on obtaining the transformation which is biorthogonal to the discrete Fourier transform of the time series. Such a transformation yields a new decomposition for the inverse of a Toeplitz matrix and enables the representation of the Gaussian likelihood within the frequency domain. We show that the difference between the Gaussian and Whittle likelihood is due to the omission of the best linear predictions outside the domain of observation in the periodogram associated with the Whittle likelihood. Based on this result, we obtain an approximation for the difference between the Gaussian and Whittle likelihoods in terms of the best fitting, finite order autoregressive parameters. These approximations are used to define two new frequency domain quasi-likelihoods criteria. We show that these new criteria can yield a better approximation of the spectral divergence criterion, as compared to both the Gaussian and Whittle likelihoods. In simulations, we show that the proposed estimators have satisfactory finite sample properties.

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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