  In the theory of belief functions, many measures of uncertainty have been
introduced. However, it is not always easy to understand what these measures
really try to represent. In this paper, we re-interpret some measures of
uncertainty in the theory of belief functions. We present some interests and
drawbacks of the existing measures. On these observations, we introduce a
measure of contradiction. Therefore, we present some degrees of non-specificity
and Bayesianity of a mass. We propose a degree of specificity based on the
distance between a mass and its most specific associated mass. We also show how
to use the degree of specificity to measure the specificity of a fusion rule.
Illustrations on simple examples are given.
