DIRECT DETERMINATION OF THE DERIVATIVES OF CONDUCTIVITY AT THE BOUNDARY FROM THE LOCALIZED DIRICHLET TO NEUMANN MAP

We consider the problem of determining conductivity of the medium from the measurements of the electric potential on the boundary and the corresponding current flux across the bound- ary. We give a formula for reconstructing the conductivity and its normal derivative at the point of the boundary simultaneously from the localized Dirichlet to Neumann map around that point.