Rothkopf Morse Code Data

Description

A standard data set for Multidimensional Scaling (MDS) obtained by Rothkopf based on the confusion rates observed by exposing subjects to pairs of morse codes.

Usage

data(morsecodes)

Format

9 data sets used for analyzing the data in XGvis and XGobi.

Details

The raw data from the XGvis directory may be read as
mc.raw <- as.matrix(read.table("....xgobi/data_xgvis/morsecodes.raw"))
dimnames(mc.raw) <- NULL; storage.mode(mc.raw) <- "integer"
morsecodes.raw <- mc.raw.

The *.dist matrix is produced from the raw data by
mc.sim <- (mc.raw + t(mc.raw))/2 ; ds <- diag(mc.sim)
morsecodes.dist <- rep(ds,36) + rep(ds,rep(36,36)) - 2*mc.sim,
i.e., d[i,j] := s[i,i] + s[j,j] - 2 * s[i,j].

Source

Contained in the ‘data_xgvis’ subdirectory of the XGobi and XGvis source bundle, available via http://www.research.att.com/areas/stat/xgobi/index.html#download.

References

A. Buja, D. F. Swayne, M. Littman, & N. Dean (1998). XGvis: Interactive Data Visualization with Multidimensional Scaling. http://www.research.att.com/areas/stat/xgobi/xgvis98.ps.gz.

Examples

data(morsecodes)
ls.str(pat="^morsecode")
morsecodes.row # remember what you learned in...
## real row names
(mc.row <- paste(morsecodes.row[,1], morsecodes.row[,2]))[1:8]

image(1:36, 1:36, morsecodes.raw, main="`morsecodes' raw confusion rates")
text(1:36,1:36, morsecodes.row[,1])

##--> help(xgvis) for running multidimensional scaling (MDS) and XGobi on these

Results