Anthropometry (version 1.1)

accommodation: Data preprocessing before computing archetypes

Description

This function allows us to preprocess the data before computing archetypes and archetypoids. First, depending on the problem, it is possible to standardize the data or not. Second, it is possible to use the Mahalanobis distance or a depth procedure to select the accommodated subsample of data.

Usage

accommodation(dataRaw,stand,percAccomm,mahal=TRUE)

Arguments

dataRaw

Raw data. Each row corresponds to an observation and each column corresponds to an anthropometric variable. All variables are numeric.

stand

A logical value. If TRUE (FALSE) the data are (not) standardized. This option will depend on the problem.

percAccomm

Percentage of the population to accommodate (value between 0 and 1). When this percentage is equal to 1 all the individuals will be accommodated.

mahal

If percAccom is different from 1, then mahal=TRUE (mahal=FALSE) indicates that the Mahalanobis distance (a depth procedure) will be used to select the accommodated subsample of data.

Value

• A list with the following elements:

  data: Database after preprocessing.

  indivYes: Individuals who belong to data.

  indivNo: Individuals discarded in the accommodation procedure.

Details

In somes cases, the depth procedure has the disadvantage that the desired percentage of accommodation is not under control of the analyst and it could not coincide exactly with percAccomm.

References

Epifanio, I., Vinue, G., and Alemany, S., (2013). Archetypal analysis: contributions for estimating boundary cases in multivariate accommodation problem, Computers & Industrial Engineering 64, 757--765.

Genest, M., Masse, J.-C., and Plante, J.-F., (2012). depth: Depth functions tools for multivariate analysis. R package version 2.0-0.

Examples

m <- dataUSAF
#Variable selection:
sel <- c(48,40,39,33,34,36)
#Changing to inches: 
mpulg <- m[,sel] / (10 * 2.54)

#Data pre-processing:
preproc <- accommodation(mpulg,TRUE,0.95,TRUE) 
preproc <- accommodation(mpulg,TRUE,0.95,FALSE)