%0 Journal Article %A Pogoruі, А. А. %A Rodríguez-Dagnіno, Ramón М. %D 2010 %F zu2:13404 %J Theor. Probability and Math. Statist. %N 83 %T Asymptotic expansion for transport processes in semi-Markov media %U http://eprints.zu.edu.ua/13404/ %X In this paper we study asymptotic expansions for a solution of the singularly perturbed equation for a functional of a semi-Markov random evolution on the line. By using the method for solutions of singularly perturbed equations, we obtain the solution in the form of a series of regular and singular terms. The first regular term satisfies a diffusion-type equation, and the first singular term is a semigroup with the infinitesimal operator of the respective related bivariate process. Each regular and singular term can be calculated recursively.