A special Class of Stochastic PERT Networks

Considering the network structure is one of the new approaches in studying stochastic PERT networks (SPN). In this paper, planar networks are studied as a special class of networks. Two structural reducible mechanisms titled arc contraction and deletion are developed to convert any planar network to a series-parallel network structure.&#10In series-parallel SPN, the completion time distribution function can be calculated only by means of multiplication and convolution operations. For the first time, series-parallel networks are studied on the basis of the structural viewpoint. These networks belong to planar networks class. A key theorem provides capability of application of these mechanisms for non series-parallel planar networks&#10