. Author manuscript; available in PMC: 2009 Oct 6.

Published in final edited form as: Chem Res Toxicol. 2008 May 8;21(6):1304–1314. doi: 10.1021/tx800063r

Table 2.

Classification of hERG Active and Nonactive Compounds Using Shape Signatures Descriptors with Different Methods

			leave-20-out testing^d
classification method^a	descriptors^b	10-fold cross-validation^c (%)	SE (%)	SP (%)	Q (%)	C
SVM	shape only	77	70	68	69	0.390
UFS-SVM	shape + charges	78	73	74	74	0.488
k-NN (k = 7)	shape only	68	79	53	66	0.343
k-NN (k = 3)	shape + charges	69	79	56	67	0.367

The specified values of k for k-NN classifications are those that yield the maximum average overall prediction accuracies Q for the leave-20-out experiments.

“Shape only” label descriptor sets derived from the 1D Shape Signatures histograms, and “shape + charges” designates descriptors sets based on the 2D Shape Signatures histograms.

This column lists prediction accuracies estimated from 10-fold cross-validations performed on the entire data set.

The tabulated values of SE, SP, Q, and C are averaged over 30 different hold-out test sets.