  In an open, constantly changing and collaborative environment like the
forthcoming Semantic Web, it is reasonable to expect that knowledge sources
will contain noise and inaccuracies. It is well known, as the logical
foundation of the Semantic Web, description logic is lack of the ability of
tolerating inconsistent or incomplete data. Recently, the ability of
paraconsistent approaches in Semantic Web is weaker in this paper, we present a
tableau algorithm based on sign transformation in Semantic Web which holds the
stronger ability of reasoning. We prove that the tableau algorithm is decidable
which hold the same function of classical tableau algorithm for consistent
knowledge bases.
