IntroductionThe topology optimization has more than 100 years of history and still it is an expanding field in structural optimization. The numerical procedure for FE (finite element) based topology optimization of continuum type of structures was elaborated first by Rossow and Taylor [19] in 1973, but the real expansion started at the end of 80-s [4,20]. The majority of the papers still deal with deterministic problems. During these years several optimal topologies were numerically calculated but the analytical confirmations -which have come recently (Rozvany [21], Sokółet. al [22]) -are mostly missing. Until the end of the last century almost one could not find any publication on topology optimization considering uncertainties.During the last years before the millennium almost there were no publications in the topic of probability based topology optimization. The stochastic optimization works of Marti and Stöckl [16,17] provide early information about this topic. The paper of Duan et al. [5] is among the very first publications in the field of uncertainty based topology optimization. This work presents an entropy-based topological optimization method for truss structures by the use of iteration technique. Also a truss topology optimization (layout optimization) of the object of the paper of Alvarez and Carrasco [1] in case stochastic loading. They showed mathematically that a problem of finding the truss of minimum expected compliance (stability of the members are not considered) under stochastic loading conditions is equivalent to the dual of a special convex minimax problem. Dunning et al. [6,7] introduce an efficient and accurate approach to robust structural topology optimization for continuum type of problems. The objective is to minimize expected compliance with uncertainty in loading magnitude and applied direction, where uncertainties are assumed normally distributed and statistically independent. This approach is analogous to a multiple load case problem where load cases and weights are derived analytically to accurately and efficiently compute expected compliance and sensitivities. Illustrative examples using a level-set-based topology optimization method are then used to demonstrate the proposed approach.Topology optimization with uncertainty in the magnitude and