Document clustering involves the use of descriptors and descriptor extraction. The HOG descriptor has a few key advantages over other descriptors. The interface devices are also defined with subclass descriptors. The parameters are normalised slope descriptors (NSDs) used in EEG. Special programs are available to override the standard timing descriptors from EDID data. Most adjectives can also be used as personality descriptors. The PCA-SIFT descriptors and shape context descriptors both performed fairly poorly on both data sets. Note that these descriptors are merely commonly used examples. This includes manipulation of its file descriptors, memory, and registers. The "descriptors" or "subject headings" are arranged in a hierarchy. A given index can have multiple possible descriptors. It currently consists of five age categories and nine content descriptors. Channels are analogous to "file descriptors" found in Unix-like operating systems. The ShapeDNA is one of the first spectral shape descriptors. These features may include molecular surface / complementary surface descriptors.