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dCovTS (version 1.0)

ADCFplot: Auto-distance correlation plot

Description

The function plots the estimated auto-distance correlation function obtained by ADCF.

Usage

ADCFplot(x, MaxLag = 15, ylim = NULL, main = NULL, method = c("Wild Bootstrap", "Subsampling"), b = 499)

Arguments

x
numeric vector or univariate time series.
MaxLag
maximum lag order at which to plot ADCF. Default is 15.
ylim
numeric vector of length 2 indicating the y limits of the plot. The default value, NULL, indicates that the range $(0,v)$, where $v$ is the maximum number between 1 and the empirical critical values, should be used.
main
title of the plot.
method
character string indicating the method to use for obtaining the 95% critical values. Possible choices are "Wild Bootstrap" (the default) and "Subsampling".
b
the number of Wild bootstrap replications for constructing the 95% empirical critical values. Default is 499.

Value

A plot of the estimated ADCF values. It also returns a list with
ADCF
The sample auto-distance correlation function for all lags specified by MaxLag.
method
The method followed for computing the 95% confidence intervals of the plot.
critical.value
The critical value shown in the plot.

Details

Fokianos and Pitsillou (2016) showed that the sample auto-distance covariance function ADCV (and thus ADCF) can be expressed as a V-statistic of order two, which under the null hypothesis of independence is degenerate. Thus, constructing a plot analogous to the traditional autocorrelation plot where the confidence intervals are obtained simultaneously, turns to be a complicated task. To overcome this issue, the 95% confidence intervals shown in the plot (dotted blue horizontal line) are computed simultaneously via Monte Carlo simulation, and in particular via the Independent Wild Bootstrap approach (Shao, 2010; Leucht and Neumann, 2013). The reader is referred to Fokianos and Pitsillou (2016, Section 6.2) for the steps followed. mADCFplot returns an analogous plot of the estimated auto-distance correlation function for a multivariate time series.

In addition, one can compute the pairwise 95% critical values via the subsampling approach suggested by Zhou (2012, Section 5.1). That is, the critical values are obtained at each lag separately. The block size of the procedure is based on the minimum volatility method proposed by Politis et al. (1999, Section 9.4.2).

References

Fokianos K. and M. Pitsillou (2016). On multivariate auto-distance covariance and correlation functions. Submitted for publication.

Leucht, A. and M. H. Neumann (2013). Dependent wild bootstrap for degenerate U- and V- statistics. Journal of Multivariate Analysis $\textbf{117}$, 257-280, http://dx.doi.org/10.1016/j.jmva.2013.03.003.

Politis, N. P., J. P. Romano and M. Wolf (1999). Subsampling. New York: Springer.

Shao, X. (2010). The dependent wild bootstrap. Journal of the American Statistical Association $\textbf{105}$, 218-235, http://dx.doi.org/10.1198/jasa.2009.tm08744.

Zhou, Z. (2012). Measuring nonlinear dependence in time series, a distance correlation approach. Journal of Time Series Analysis $\textbf{33}$, 438-457, http://dx.doi.org/10.1111/j.1467-9892.2011.00780.x.

See Also

ADCF, ADCV, mADCFplot

Examples

Run this code
## Not run: ADCFplot(rnorm(100),ylim=c(0,0.4),method="Subs")

ADCFplot(mdeaths,method="Wild",b=100)

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