transformseries: Transformation of series of data

In mem: The Moving Epidemic Method

Transformation of series of data

Description

Function transformseries transforms whole datasets.

Usage

transformseries(i.data, i.transformation = 1, ...)

Arguments

i.data	Historical data series.
i.transformation	Transformation to apply to the dataset.
...	other paramaters to be used by functions to fit two waves.

Details

Input data must be a data.frame with each column a surveillance season and each row a week.

Transformation options:

• 1 No transformation

• 2 Odd

• 3 Fill missing data

• 4 Smoothing regression

• 5 Two waves (observed)

• 6 Two waves (expected)

• 7 Loess

• 8 Spline

• 9 Moving Average

Fill missings sustitute missing values with predicted values from a loess regression fit. If does not impute leading or trailing missings, only missings in the middle of the season.

Odd calculates the odd: p divided by 1-p.

Loess substitute the dataset with predicted values from a loess regression fit.

Spline fits a cubic smoothing spline to the supplied data.

Two waves (observed) is used when there are two waves per season. It divides the original dataset in two using a mixture of two normal distributions. The expected option uses the same procedure but also substitutes all data with predicted values of the mixture fit.

Moving Average has an additional parameter i.number for the number of observation to calculate the average.

Value

transformseries The transformed dataset.

Author(s)

Jose E. Lozano [e-mail]

References

Vega T, Lozano JE, Ortiz de Lejarazu R, Gutierrez Perez M. Modelling influenza epidemic - can we detect the beginning and predict the intensity and duration? Int Congr Ser. 2004 Jun;1263:281-3.

Vega T, Lozano JE, Meerhoff T, Snacken R, Mott J, Ortiz de Lejarazu R, et al. Influenza surveillance in Europe: establishing epidemic thresholds by the moving epidemic method. Influenza Other Respir Viruses. 2013 Jul;7(4):546-58. DOI:10.1111/j.1750-2659.2012.00422.x.

Vega T, Lozano JE, Meerhoff T, Snacken R, Beaute J, Jorgensen P, et al. Influenza surveillance in Europe: comparing intensity levels calculated using the moving epidemic method. Influenza Other Respir Viruses. 2015 Sep;9(5):234-46. DOI:10.1111/irv.12330.

Lozano JE. lozalojo/mem: Second release of the MEM R library. Zenodo [Internet]. [cited 2017 Feb 1]; Available from: https://zenodo.org/record/165983. DOI:10.5281/zenodo.165983

Examples

# Castilla y Leon Influenza Rates data
data(flucyl)
# Data of the last season
transformseries(flucyl, 2)

mem documentation built on July 9, 2023, 6:34 p.m.