  We study the low energy evolution of coupling constants of the standard model
and show that gauge coupling unification can be achieved at the electroweak
scale with a suitable normalization. We choose the grand unification group to
be the semidirect product of Spin(8) by S_3. In this case the three low energy
gauge couplings and the two scalar self-couplings are determined in terms of
two independent parameters. In particular, it gives a precise prediction for
the mass of the Higgs boson.
