  Higher-dimensional field theory has been applied to explore various issues in
recent particle physics such as the gauge hierarchy problem. In order for such
approaches to be viable, a crucial ingredient is to fix the sizes of extra
dimensions at some finite values, which sizes are generically free parameters
in the theory. In this paper, we present several schemes to determine the
radius of extra dimension in warped five-dimensional theory. In every case, a
non-vanishing Fayet-Iliopoulos term for abelian gauge factor plays a crucial
role for the radius stabilization. It is radiatively generated in the presence
of charged matter fields and the compactification is therefore spontaneous, not
forced by selected operators. The low-energy supersymmetry is broken or
unbroken, and the radius can be fixed to give a small or large scale hierarchy
without any fine tuning of parameters. We also discuss a model of the radius
stabilization correlated with Yukawa hierarchy and supersymmetry breaking.
