In this master thesis we investigate implications of the Domain-Wall/Cosmology (DW/C) correspondence on one-point functions of holographic RG-flows. The thesis gives a detailed computation of linearized gauge-invariant Einstein equations in (d+1) dimensions while making the DW/C correspondence explicit. Although holographic renormalization has previously been studied on Lorentzian manifolds, we extend its study to Lorentzian domain-wall solutions with a parameter η. This parameter is introduced to easily travel from domain-walls to cosmologies in the context of the DW/C correspondence. We present the calculation of the vacuum expectation value of general scalar boundary operators of conformal weight Δ dual to a (d+1)-dimensional bulk theory...