We consider a probabilistic model for the Steiner Tree problem. Under this model the problem is defined in a 2-stage setting over a first-stage complete weighted graph having its vertices associated with a probability of presence (independently each from another) in the second stage. A first-stage feasible solution on the input graph might become infeasible in the second stage, when certain vertices of the graph fail. Therefore, a well defined modification strategy is devised for modifying the remainders of a first-stage solution to render it secondstage feasible. The objective is to minimize the expected weight of the second-stage solution over the distribution of all possible second-stage materializable subgraphs of the input graph. We recognize two complementary computational problems in this setting, one being the a priori computation of first-stage decisions given a particular modification strategy, and the second being the cost-efficient modification of a first-stage f...
Vangelis Th. Paschos, Orestis Telelis, Vassilis Zi