Kumar and Takai have proposed an architecture for the decentralized prognosis of discrete-event systems (DES), where several local prognosers cooperate to predict failures in a DES. In this paper, we first present the proposition (Kumar and Takai, "Decentralized prognosis of failures in discrete event systems," IEEE Trans. Autom. Control, vol. 55, no. 1, pp. 48-59, Jan. 2010) as a disjunctive architecture, and then we develop a conjunctive architecture which is dual and complementary to the disjunctive one. We also propose a mixed architecture that combines and generalizes the disjunctive and conjunctive architectures. We finally show that our work can be easily extended to predict a failure at least k steps before its occurrence, for a given k >; 1.