nir {kohonen} | R Documentation |
A data object containing near-infrared spectra of ternary mixtures of ethanol, water and iso-propanol, measured at five different temperatures (30, 40, ..., 70 degrees Centigrade).
F. Wulfert , W.Th. Kok, A.K. Smilde: Anal. Chem. 1998, 1761-1767
data(nir) set.seed(3) nirnet <- xyf(data = nir$spectra[nir$training,], Y = nir$composition[nir$training,], xweight=.75, grid = somgrid(6, 6, "hexagonal"), rlen=500) plot(nirnet, "counts", main="Counts") ## Focus on compound 2 (water): dev.new(width = 14) par(mfrow = c(1,2)) set.seed(13) nirnet <- xyf(data = nir$spectra[nir$training,], Y = nir$composition[nir$training, 2], grid = somgrid(6, 6, "hexagonal"), rlen=500) water.xyf <- predict(nirnet)$prediction plot(nirnet, "property", property = water.xyf, main="Prediction of water content") ## Plot temperatures as circles symbols(nirnet$grid$pts[nirnet$unit.classif,] + matrix(rnorm(sum(nir$training)*2, sd=.1), ncol=2), circles = (nir$temperature[nir$training] - 20)/250, inches = FALSE, add = TRUE) ## Model temperatures set.seed(13) nirnet2 <- xyf(data = nir$spectra[nir$training,], Y = nir$temperature[nir$training], xweight=.25, grid = somgrid(6, 6, "hexagonal"), rlen=500) temp.xyf <- predict(nirnet2)$prediction plot(nirnet2, "property", property = temp.xyf, palette.name = rainbow, main="Prediction of temperatures") ## Plot concentrations of water as circles symbols(nirnet2$grid$pts[nirnet2$unit.classif,] + matrix(rnorm(sum(nir$training)*2, sd=.1), ncol=2), circles = 0.05 + 0.4 * nir$composition[nir$training,2], inches = FALSE, add = TRUE)