Since the pioneering work of Wiener and Shannon in the field of inform
ation processing, many developments have focused on the definition of
uncertainty measures and their applications to various fields, which c
ould be considered as numerical rather than symbolic. During the past
twelve years, the researchers in artificial intelligence, who are usua
lly preferring symbolic methods, have rediscovered the importance of t
hese works and used them to manage the information in knowledge-based
systems. We present a brief survey of the different approaches in this
framework.