Single-class vs. Multi-classes lines
l Single-class line
¡ Each line with a single element
¡ e.g. <title> Automatic Document Metadata Extraction
using Support Vector Machine </title>
l Multi-classes line
¡ Each line with several elements
¡ e.g. <author> Hui Han, C. Lee Giles, Ere
Manavoglu</author>