  Acyclic networks are a class of complex networks in which links are directed
and don't have closed loops. Here we present an algorithm for transforming an
ordinary undirected complex network into an acyclic one. Further analysis of an
acyclic network allows finding structural properties of the network. With our
approach one can find the communities and key nodes in complex networks. Also
we propose a new parameter of complex networks which can mark most vulnerable
nodes of the system. The proposed algorithm can be applied to finding
communities and bottlenecks in general complex networks.
