cluster (version 2.0.4)

pluton: Isotopic Composition Plutonium Batches

Description

The pluton data frame has 45 rows and 4 columns, containing percentages of isotopic composition of 45 Plutonium batches.

Usage

data(pluton)

Format

This data frame contains the following columns:

Pu238

the percentages of $(238)Pu$, always less than 2 percent.

Pu239

the percentages of $(239)Pu$, typically between 60 and 80 percent (from neutron capture of Uranium, $(238)U$).

Pu240

percentage of the plutonium 240 isotope.

Pu241

percentage of the plutonium 241 isotope.

Source

Available as ‘pluton.dat’ from the archive of the University of Antwerpen, ‘..../datasets/clusplot-examples.tar.gz’, no longer available.

Details

Note that the percentage of plutonium~242 can be computed from the other four percentages, see the examples.

In the reference below it is explained why it is very desirable to combine these plutonium patches in three groups of similar size.

References

Rousseeuw, P.J. and Kaufman, L and Trauwaert, E. (1996) Fuzzy clustering using scatter matrices, Computational Statistics and Data Analysis 23(1), 135--151.

Examples

data(pluton)

hist(apply(pluton,1,sum), col = "gray") # between 94% and 100%
pu5 <- pluton
pu5$Pu242 <- 100 - apply(pluton,1,sum) # the remaining isotope.
pairs(pu5)