  Recently, we have introduced a unified theory to deal with perturbative and
non-perturbative QCD contributions to hadronic structure functions in deep
inelastic scattering. This formulation is realized by combining the coordinate
space approach based on light-front current algebra techniques and the momentum
space approach based on Fock space expansion methods in the Hamiltonian
formalism of light-front field theory. In this work we show how a perturbative
analysis in the light-front Hamiltonian formalism leads to the factorization
scheme we have proposed recently. The analysis also shows that the scaling
violations due to perturbative QCD corrections can be rather easily addressed
in this framework by simply replacing the hadron target by dressed parton
target and then carrying out a systematic expansion in the coupling constant
$\alpha_s$ based on the perturbative QCD expansion of the dressed parton
target. The tools employed for this calculation are those available from
light-front old-fashioned perturbation theory. We present the complete set of
calculations of unpolarized and polarized deep inelastic structure functions to
order $\alpha_s$. We extract the relevant splitting functions in all the cases.
We explicitly verify all the sum rules to order $\alpha_s$. We demonstrate the
validity of approximations made in the derivation of the new factorization
scheme. This is achieved with the help of detailed calculations of the
evolution of structure function of a composite system carried out using
multi-parton wavefunctions.
