Description Usage Arguments Details Value Author(s) References See Also
generic_ews
is used to estimate statistical
moments within rolling windows along a timeserie
1 2 3 4 5 |
timeseries |
a numeric vector of the observed univariate timeseries values or a numeric matrix where the first column represents the time index and the second the observed timeseries values. Use vectors/matrices with headings. If the powerspectrum is to be plotted as well, the timeseries lenght should be even number. |
winsize |
is the size of the rolling window expressed as percentage of the timeseries length (must be numeric between 0 and 100). Default is 50%. |
bandwidth |
is the bandwidth used for the Gaussian
kernel when gaussian filtering is applied. It is
expressed as percentage of the timeseries length (must be
numeric between 0 and 100). Alternatively it can be given
by the bandwidth selector |
detrending |
the timeseries can be
detrended/filtered prior to analysis. There are four
options: |
logtransform |
logical. If TRUE data are logtransformed prior to analysis as log(X+1). Default is FALSE. |
interpolate |
logical. If TRUE linear interpolation is applied to produce a timeseries of equal length as the original. Default is FALSE (assumes there are no gaps in the timeseries). |
AR_n |
logical. If TRUE the best fitted AR(n) model is fitted to the data. Default is FALSE. |
powerspectrum |
logical. If TRUE the power spectrum within each rolling window is plotted. Default is FALSE. |
see ref below
generic_ews
returns a matrix that contains:
tim |
the time index. |
ar1 |
the |
sd |
the |
sk |
the |
kurt |
the |
cv |
the |
returnrate |
the return rate of the data estimated
as |
densratio |
the |
acf1 |
the |
In addition, generic_ews
returns three plots. The
first plot contains the original data, the
detrending/filtering applied and the residuals (if
selected), and all the moment statistics. For each
statistic trends are estimated by the nonparametric
Kendall tau correlation. The second plot, if asked,
quantifies resilience indicators fitting AR(n) selected
by the Akaike Information Criterion. The third plot, if
asked, is the power spectrum estimated by
spec.ar
for all frequencies within each
rolling window.
Vasilis Dakos vasilis.dakos@gmail.com
Ives, A. R. (1995). "Measuring resilience in stochastic systems." Ecological Monographs 65: 217-233
Dakos, V., et al (2008). "Slowing down as an early warning signal for abrupt climate change." Proceedings of the National Academy of Sciences 105(38): 14308-14312
Dakos, V., et al (2012)."Methods for Detecting Early Warnings of Critical Transitions in Time Series Illustrated Using Simulated Ecological Data." PLoS ONE 7(7): e41010. doi:10.1371/journal.pone.0041010
generic_ews
; ddjnonparam_ews
;
bdstest_ews
; sensitivity_ews
;
surrogates_ews
; ch_ews
;
movpotential_ews
;
livpotential_ews
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