  We present numerical simulations for unpolarized and polarized structure
functions in a chiral soliton model. The soliton is constructed
self-consistently from quark fields from which the structure functions are
extracted. Central to the project is the implementation of regularizing the
Dirac sea (or vacuum) contribution to structure functions from first
principles. We discuss in detail how sum rules are realized at the level of the
quark wave-functions in momentum space. The comparison with experimental data
is convincing for the polarized structure functions but exhibits some
discrepancies in the unpolarized case. The vacuum contribution to the polarized
structure functions is particularly small.
